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Fulltext Effect of Polymethylmethacrylate-Hydroxyapatite Composites on Callus Formation and Compressive Strength in Goat Vertebral Body

Komang-Agung IS, Hydravianto L, Sindrawati O, William PS

Malays Orthop J, 2018 Nov;12(3):6-13.
PMID: 30555640 DOI: 10.5704/MOJ.1811.002

Introduction: Percutaneous vertebroplasty (PV) is one of the available treatments for vertebral compression fracture (VCF). Polymethylmethacrylate (PMMA) is the most common bone substitute used in the procedure, but it has several disadvantages. Bioceramic material, such as hydroxyapatite (HA), has better biological activity compared to PMMA. The aim of this study was to find an optimal biomaterial compound which offers the best mechanical and biological properties to be used in PV. Materials and Methods: This was an experimental study with goat (Capra aegagrus hircus) as an animal model. The animals' vertebral columns were injected with PMMA-HA compound. Animal samples were divided into four groups, and each group received a different proportion of PMMA:HA compound. The mechanical and biological effects of the compound on the bone were then analysed. The mechanical effect was assessed by measuring the vertebral body's compressive strength. Meanwhile, the biological effect was assessed by analysing the callus formation in the vertebral body. Results: The optimal callus formation and compressive strength was observed in the group receiving PMMA:HA with a 1:2 ratio. Conclusion: A mixture of PMMA and HA increases the quality of callus formation and the material's compressive strength. The optimum ratio of PMMA:HA in the compound is 1:2.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Histological changes of immediate skin expansion of the distal limb of rats

Ali AK, Abubakar AA, Kaka U, Radzi Z, Khairuddin NH, Yusoff MSM, et al.

Vet World, 2018 Dec;11(12):1706-1711.
PMID: 30774262 DOI: 10.14202/vetworld.2018.1706-1711

Aim: Tissue expansion is an applicable technique to reconstruct many surgical defects. The aim of this research was to evaluate the histological changes caused by immediate skin tissue expansion in rats as an animal model.
Materials and Methods: Immediate skin tissue expansion in 18 adult female rats was performed using three different sizes (small, medium, and big) of polymethylmethacrylate tissue expanders at the dorsal surface of the metatarsal area of the right limb. The contralateral limb was served as the control. The tissue expanders were surgically implanted and kept for 15 days.
Results: The immediate skin expansion resulted in histological changes such as the increased thickness of the epidermal layer, the reduction of the dermal layer, an elevated number of fibroblast as well as increased vascularity. Furthermore, skin adnexal structures such as hair follicles and sebaceous glands were farther apart.
Conclusion: The rat skin was able to rapidly adjust and compensate against a specific range of immediate mechanical expansion. The histological changes suggest that the tissues were prepared to withstand the increased external forces, in addition to create possibly additional skin in a relatively short-term period.

Matched MeSH terms: Polymethyl Methacrylate
Characterization of MOSkin detector for in vivo dose verification during Cobalt-60 high dose-rate intracavitary brachytherapy

Jamalludin Z, Jong WL, Abdul Malik R, Rosenfeld A, Ung NM

Phys Med, 2019 Feb;58:1-7.
PMID: 30824140 DOI: 10.1016/j.ejmp.2019.01.010

In vivo dosimetry in high dose-rate (HDR) intracavitary brachytherapy (ICBT) is important for assessing the true dose received by surrounding organs at risk during treatment. It also serves as part of the treatment delivery quality assurance and verification program with the use of a suitable dosimeter. Such a dosimeter should be characterized under brachytherapy conditions before clinical application to ensure the accuracy of in vivo measurement. In this study, a MOSFET-based detector, MOSkin, was calibrated and characterized under HDR Cobalt-60 (Co-60) brachytherapy source. MOSkin possessed the major advantages of having small physical and dosimetric sizes of 4.8 × 10-6 mm3 with the ability to provide real-time measurements. Using solid water and polymethyl methacrylate (PMMA) phantom, the detectors' reproducibility, linearity, angular and distance dependency was tested for its suitability as an in vivo detector. Correction factors to account for differences in depth measurements were determined. The MOSkin detector showed a reliable response when tested under Co-60 brachytherapy range of doses with an excellent linearity of R2 = 0.9997 and acceptable reproducibility. A phantom verification study was also conducted to verify the differences between MOSkin responses and treatment planning (TPS) calculated doses. By taking into account several correction factors, deviations ranging between 0.01 and 0.4 Gy were found between MOSkin measured and TPS doses at measurement distance of 20-55 mm. The use of MOSkin as the dosimeter of choice for in vivo dosimetry under Co-60 brachytherapy condition is feasible.

Matched MeSH terms: Polymethyl Methacrylate
Application of polymethylmethacrylate-grafted cellulose as reinforcement for compatibilised polylactic acid/natural rubber blends

Rosli NA, Ahmad I, Anuar FH, Abdullah I

Carbohydr Polym, 2019 Jun 01;213:50-58.
PMID: 30879689 DOI: 10.1016/j.carbpol.2019.02.074

In this study, modified agave cellulose fibre combined by graft copolymerisation with methylmethacrylate was tested as a potential reinforcement for polylactic acid (PLA)-natural rubber/liquid natural rubber blends. Mechanical, morphological, thermal, wetting, and biodegradation characterisations were performed to assess the influence of cellulose-graft-polymethylmethacrylate (cell-g-PMMA) content on the properties of biocomposites. The addition of cell-g-PMMA improved the mechanical properties of the composites because of the chemical interaction between PLA and PMMA. Thermal stability decreased slightly upon cell-g-PMMA addition because of the low thermal stability of PMMA. A soil burial test revealed that the degradation of composites decreased with an increase in the cell-g-PMMA content. However, the weight loss after burial, which directly affected the water absorption capacity, was still higher for the cell-g-PMMA composites than for the polymer alone.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Transparent Blend of Poly(Methylmethacrylate)/Cellulose Acetate Butyrate for the Protection from Ultraviolet

Mahmood Raouf R, Abdul Wahab Z, Azowa Ibrahim N, Abidin Talib Z, Chieng BW

Polymers (Basel), 2016 Apr 14;8(4).
PMID: 30979233 DOI: 10.3390/polym8040128

The use of transparent polymers as an alternative to glass has become widespread. However, the direct exposure of these materials to climatic conditions of sunlight and heat decrease the lifetime cost of these products. The aim of this study was to minimize the harm caused by ultraviolet (UV) radiation exposure to transparent poly(methylmethacrylate) (PMMA), which usually leads to changes in the physical and chemical properties of these materials and reduced performance. This was achieved using environmentally friendly cellulose acetate butyrate (CAB). The optical, morphological, and thermal properties of CAB blended with transparent PMMA was studied using UV-VIS spectrophotometry, scanning electron microscopy, X-ray diffraction, dynamic mechanical analysis, and thermal gravimetric analysis. The results show that CAB was able to reduce the effects of UV radiation by making PMMA more transparent to UV light, thereby preventing the negative effects of trapped radiation within the compositional structure, while maintaining the amorphous structure of the blend. The results also show that CAB blended with PMMA led to some properties commensurate with the requirements of research in terms of a slight increase in the value of the modulus and the glass transition temperature for the PMMA/CAB blend.

Matched MeSH terms: Polymethyl Methacrylate
Effect of space holders on fabrication of porous titanium alloy-hydroxyapatite composite through powder injection molding

Farrahshaida Mohd Salleh, Abu Bakar Sulong, Muhammad Rafi Raza, Norhamidi Muhamad, Lim TF

Sains Malaysiana, 2017;46:1651-1657.

owder injection molding (PIM) is able to produce porous titanium alloy/hydroxyapatite composite through the space holder technique. Thermal debinding and sintering processes were the main challenges due to different properties of metal and ceramic in producing such composite. This study focused on the effect of different space holders on the physical and mechanical properties of debound and sintered porous titanium aloi/hydroxyapatite composite. The feedstock is containing of 80 wt. % of titanium alloy/hydroxyapatite with 20 wt. % of space holders such as sodium chloride (NaCl) and polymethylmethacrylate (PMMA), respectively. The binders were then removed from the injected samples by two stages of debinding; solvent and thermal debinding. The sintering was performed at three different temperatures 1100oC, 1200oC and 1300oC at a heating rate of 10oC /min and holding time of 5 h. It was found that the samples containing PMMA space holder was fractured after sintering. While, the samples containing NaCl space holder successfully formed pores and not fractured. At sintering temperature of 1300oC, the density, compressive strength and porosity volume percentages for the sintered sample containing NaCl space holder were 3.05 g/cm3, 91.7 MPa. and 11.9 vol%, respectively.

Matched MeSH terms: Polymethyl Methacrylate
Patient-Specific Reconstruction Utilizing Computer Assisted 3D Modelling for Partial Bone Flap Defect in Hybrid Cranioplasty

Low PH, Abdullah JY, Abdullah AM, Yahya S, Idris Z, Mohamad D

J Craniofac Surg, 2019 Jun 28.
PMID: 31261343 DOI: 10.1097/SCS.0000000000005713

PURPOSE: Decompressive craniectomy is a life-saving procedure in the setting of malignant brain swelling. Patients who survive require cranioplasty for anatomical reconstruction and cerebral protection. Autologous cranioplasty remains the commonest practice nowadays, but partial bone flap defects are frequently encountered. The authors, therefore, seek to develop a new technique of reconstruction for cranioplasty candidate with partial bone flap defect utilizing computer-assisted 3D modeling and printing.
METHODS: A prospective study was conducted to evaluate the outcome of a new reconstruction technique that produces patient-specific hybrid polymethyl methacrylate-autologous cranial implant. Computer-assisted 3D modeling and printing was utilized to produce patient-specific molds, which allowed real-time reconstruction of bone flap with partial defect intra-operatively.
RESULTS: Outcome assessment for 11 patients at 6 weeks and 3 months post-operatively revealed satisfactory implant alignment with favorable cosmesis. The mean visual analog scale for cosmesis was 91. Mean implant size was 50cm, and the mean duration of intra-operative reconstruction was 30 minutes. All of them revealed improvement in quality of life following surgery as measured by the SF-36 score. Cost analysis revealed that this technique is more cost-effective compared to customized cranial prosthesis.
CONCLUSION: This new technique and approach produce hybrid autologous-alloplastic bone flap that resulted in satisfactory implant alignment and favorable cosmetic outcome with relatively low costs.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Manufacture of Contact Lens of Nanoparticle-Doped Polymer Complemented with ZEMAX

Shaker LM, Al-Amiery AA, Kadhum AAH, Takriff MS

Nanomaterials (Basel), 2020 Oct 15;10(10).
PMID: 33076278 DOI: 10.3390/nano10102028

Many people suffer from myopia or hyperopia due to the refractive errors of the cornea all over the world. The use of high refractive index (RI), Abbe number (νd), and visible light transmittance (T%) polymeric contact lenses (CLs) holds great promise in vision error treatment as an alternative solution to the irreversible laser-assisted in situ keratomileusis (LASIK) surgery. Titanium dioxide nanoparticles (TiO2 NPs) have been suggested as a good candidate to rise the RI and maintain high transparency of a poly(methyl methacrylate) (PMMA)-TiO2 nanocomposite. This work includes a preparation of TiO2 NPs using the sol gel method as well as a synthesis of pure PMMA by free radical polarization and PMMA-TiO2 CLs using a cast molding method of 0.005 and 0.01 w/v concentrations and a study of their effect on the aberrated human eye. ZEMAX optical design software was used for eye modeling based on the Liou and Brennan eye model and then the pure and doped CLs were applied. Ocular performance was evaluated by modulation transfer function (MTF), spot diagram, and image simulation. The used criteria show that the best vision correction was obtained by the CL of higher doping content (p < 0.0001) and that the generated spherical and chromatic aberrations in the eye had been reduced.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Inhibition Of Stain By Some Commercially Available Oral Hygiene Products

Swaminathan, D., Moran, John, Addy, Martin

Ann Dent, 1996;3(1):-.
MyJurnal

Side effects such as abrasion of the dental hard tissue have been frequently observed following the extensive use of mechanical cleansing. As promising antiseptics like chlorhexidine produces extrinsic dental staining on long term usage, there has been increasing interest and research generated towards chemically based stain removing agents. This invitro studyexamined whether some commercial oral hygiene products could inhibit chlorhexidine derived stain independent of any mechanical cleansing action. Perspex blocks were soaked in triplicate in chlorhexidine solution for 2 minutesand stain inhibition by these products was determined by further soaking the blocks in productl water slurries for 2 minutes and finally in tea solution for I hourly periods. The optical density (OD) of each specimen was determined at each hourly interval by spectrophotometry at 395 nm and the mean values obtained. At the end of the study, most of the products inhibited stain compared to water control and there was a variation in the stain inhibitingefficacyof the products. It is thus concluded that oral hygiene products like dentifricesand mouthrinses can inhibit chlorhexidine derived extrinsic dental stain to a variable degree through a chemical action by contained ingredients.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Ionic conductivity and morphological studies of plasticized poly (methyl methacrylate) polymer electrolyte films

Osman, Z., Othman, L., Md Isa, K.B., Ahmad, A., Kamarulzaman, N.

ASM Science Journal, 2010;4(1):55-61.
MyJurnal

In this study polymer electrolytes composed of poly(methyl methacrylate) (PMMA) as a host polymer and ethylene carbonate (EC) as a plasticizer complexed with different lithium salts, i.e. lithium tetrafluoroborate (LiBF4) and lithium triflate (LiCF3SO3) were prepared by the solution casting technique. The conductivities of the films were characterized by impedance spectroscopy. At room temperature, the highest conductivities were 4.07 × 10–7S cm–1 and 3.40 × 10–5 S cm–1 achieved, respectively from the films containing 30 wt% LiBF4 in the PMMA-EC-LiBF4 system and 35 wt% LiCF3SO3 in the PMMA-EC-LiCF3SO3 system. The conductivity-temperature dependence of the films seemed to obey the Arrhenius equation in which the ion transport in these materials was thermally assisted. Scanning electron microscopy analysis showed that the surface of PMMA-EC-LiCF3SO3 film was smooth and homogeneous, hence lithium ions could traverse through the PMMA-EC-LiCF3SO3 film more easily compared to the PMMA-EC-LiBF4 film. X-Ray diffraction studies revealed that complexation had occurred and the complexes formed were amorphous.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext 13-year-old exposed interlocking nail: a case report

Chua, Y.C.J., Lim, L.A., Hudzairy, A.

Malays Orthop J, 2009;3(1):91-94.
MyJurnal

We are reporting a case of post-traumatic chronic osteomyelitis of the tibia with an open wound exposing an intra medullar nail implant for 13 years. The patient presented with fresh ipsilateral tibia plateau fracture. He was treated by removal of the implant, debridement and local placement of Gentamicin-impregnated PMMA beads according to guidelines of two-stage Belfast technique . After five months of wound treatment, the exposed bone was covered by healthy granulation tissue and the patient was able to fully bear weight.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext The Use of PROSTALAC in Two-stage Reimplantation of Septic Total Knee and Hip Arthroplasty

Wam, B.L., Chee, E.K., Ewe, T.W.

Malays Orthop J, 2010;4(3):11-15.
MyJurnal

The PROSTALAC (PROSThesis Antibiotic Loaded Acrylic Cement) functional spacer is made with antibiotic-loaded acrylic cement. We use it as an interim spacer in two-stage exchange arthroplasty in cases of infected total knee or total hip replacement. PROSTALAC allows continuous rehabilitation between stages as it maintains good alignment and stability of the joint with a reasonable range of movement. It also helps to maintain the soft-tissue planes, thereby facilitating the second-stage procedure. We report here early outcomes of the use of PROSTALAC in 5 patients - 3 in total knee replacements, 1 in a total hip replacement and 1 in a bipolar hemiarthroplasty.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext A custom made phantom for dosimetric audit and quality assurance of three-dimensional conformal radiotherapy

Radaideh, K.M., Matalqah, L.M., Tajuddin, A.A., Lee Luen, F.W., Bauk, S., Abdel Munem, E.M.E

Jurnal Sains Nuklear Malaysia, 2012;24(1):0-0.
MyJurnal

The ultimate check of the actual dose delivered to a patient in radiotherapy can be achieved by using dosimetric measurements. The aims of this study were to develop and evaluate a custom handmade head and neck phantom for evaluation of Three-Dimensional Conformal Radiation Therapy (3D-CRT) dose planning and delivery. A phantom of head and neck region of a medium built male patient with nasopharyngeal cancer was constructed from Perspex material. Primary and secondary Planning Target Volume (PTV) and twelve Organs at Risk (OAR) were delineated using Treatment Planning System (TPS) guided by computed tomography printout transverse images. One hundred and seven (107) holes distributed among the organs were loaded with Rod-shaped Thermoluminescent dosimeters (LiF:Mg,Ti TLDs) after common and individual calibration. Head and neck phantom was imaged, planned and irradiated conformally (3D-CRT) by linear accelerator (LINAC Siemens Artiste). The planned predicted doses by TPS at PTV and OAR regions were obtained and compared with the TLD measured doses using the phantom. Repeated TLD measurements were reproducible with a percent standard deviation of < 3.5%. Moreover, the average of dose discrepancies between TLDs reading and TPS predicted doses were found to be < 5.3%. The phantom’s preliminary results have proved to be a valuable tool for 3D-CRT treatment dose verification.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Synthesis and characterization of β-tricalcium phosphate ceramic via sol-gel method

Mohd Al Amin Muhamad Nor, Maryam Mohd Ridzuan, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2009;2009(1):199-205.
MyJurnal

Ceramic materials play key role in several biomedical applications. One of them is bone graft which is use in treating bone defect which caused by injury or osteoporosis. Calcium phosphates based ceramic are preferred as bone grafts in hard tissue engineering because of their chemical compositions are similar to the composition of human bone, superior bioresorbable and bioactivity. In this study, β-tricalcium phosphate (β-TCP) ceramic was synthesized by using sol-gel method. Phosphorous pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as calcium and phosphate precursors. The effects of calcination temperature on the synthesis powder were studied using the XRD, SEM-EDS and FTIR techniques. It was found that calcination temperature greatly influence the purity of the synthesized powders. The β-TCP was the dominant phase with the formation of α-TCP at calcination temperature from 600 to 800°C. Pure β-TCP was obtained at calcination of 900°C. As the temperature increased to 1000°C, the β-TCP was decomposed to for calcium phosphate oxide (CPO). The sol-gel method has some advantages over other methods, mainly its simplicity and ability to produce pure β-TCP at lower calcination temperature.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Mechanical activation of ultrafine cordierite: effect of grinding time

Affendi, A.F., Hasmaliza, M., Srimala, S.

Journal of Nuclear and Related Technologies, 2009;2009(1):247-254.
MyJurnal

In these studies, cordierite was mechanically synthesized after a sol-gel process. The effect of milling time of cordierite was investigated. Aluminium nitrate nonahydrate, magnesium nitrate hexahydrate and tetraethylorthosilicate (TEOS) were used as starting materials. Gels obtained were mechanically activated in planetary ball mill by at 300rpm grinding speed and grinding time (15min, 30min, 45min and 60min). Powders produced were characterized by X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray (EDX). XRD analysis proved that α-cordierite was formed at lower temperature (1200°C) as compliment to without grinding, whereby it is formed at1300°C. FESEM analysis shows the size of the cordierite were in submicron scale. EDX analysis proved that magnesium, aluminium, silicon and oxygen are elements existed in cordierite.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Evaluation and characterization of β-tricalcium phosphate powder prepared by CACO3/H3PO4 system

Shah Rizal Kasim, Yeong, Meng Yee, Hazizan Md. Akil, Zainal Arifin Ahmad, Hazman Seli

Journal of Nuclear and Related Technologies, 2007;2007(1):93-100.
MyJurnal

Many attempts have been focused in the past on preparing of synthetic E-tricalcium (E-TCP), which being employed as bone substitute due to its biocompatibility and resorbability. Low temperature synthesize such as sol-gel method become popular due to the high product purity and homogenous composition. Sol-gel method is less economical towards commercialization because the cost of raw materials and the yield of the product that can be achieved. This paper describes the synthesis of ETCP via mixing of CaCO3 and H3PO4 followed by calcinations process at 750qC – 1050qC. X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), fourier transformation infra-red (FTIR) were used for characterization and evaluation of the phase composition, morphology, particle size and thermal behavior of the product. E-TCP phase start to occur after calcinations at 750qC.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Structural and electrical characteristic of BA0.7SR0.3TIO3 with a secondary phase BATI2O5

Sreekantan, Srimala, Ahmad Fauzi Mohd Noor, Zainal Arifin Ahmad, Radzali Othman, West, Anthony, Sinclair, Derek

Journal of Nuclear and Related Technologies, 2007;2007(1):115-126.
MyJurnal

Barium strontium titanate (Ba0.7Sr0.3TiO3) powder was processed at temperature 80 o C by reacting titania sol in aqueous solutions that contained BaCl2, SrCl2 and NaOH at atmospheric pressure.
The structural characteristic of the powder and sintered pellet were studied using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) whereas the electrical characteristic was determined via Impedance Spectroscopy (IS) and LCR meter. The synthesized powder was found to have a tetragonal phase after heating at 1300 o C. XRD pattern also showed the presence of secondary phase BaTi2O5 (BT2). The SEM results shows the fine grain size was in the range of 0.2 Pm to 0.4 Pm whereas the large ones are approximately 0.8 Pm to 1.2 Pm The ac response of sample sintered at 1300 o C indicated that three electrically different regions. Element 1 can be assigned as a ferroelectric grain boundary region and it is actually BT2, element 2 as a ferroelectric bulk region and the third element is a conductive core which has a low resistance (200 :) and capacitance value.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Phase formation study of CuAlO2 transparent conductive oxide thin films

Hutagalung, Sabar D., Woon, Wu S., Khatijah A. Yaacob, Lockman, Zainovia

Journal of Nuclear and Related Technologies, 2007;2007(1):165-170.
MyJurnal

P-type transparent conductive oxide of copper aluminum oxide (CuAlO2) thin films were prepared by using sol-gel method with nitrate solutions as starting precursor. Copper nitrate and aluminum nitrate were selected as raw materials that provide the copper and aluminum source. The CuAlO2 thin films were deposited on pre-cleaned silicon substrate by spin-coating technique. To study of phase formation of CuAlO2, as prepared sample was dried and subjected to heat treatment at various temperatures. The heat-treated samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray (EDX). From XRD analysis result found that CuAlO2 phase was formed after annealing at 1100 o C for 4 hrs. EDX result of annealed sample at 1100 o C shows composition of Cu and Al that indicate the possibility of forming CuAlO2.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Photoprotective measures of selected sunscreens and their antioxidant adjuvantion effects in the Malaysian Climate

Khamsiah, N., Lai, N.S., Nurfarhanim, M., Nor Aimi, A.R., Mohd Syazwan, C. S., Goon, J.A.

Medicine & Health, 2012;7(2):84-96.
MyJurnal

The Malaysian skincare industry is growing rapidly with a vast number of new sunscreens being produced annually. Inadequate skincare regulations and lack of enforcement have resulted in the overrating of sunscreens’ quality. The objectives of this study were to evaluate the efficacy and safety of the local and international sunscreens and to determine the effects of adding concentrated antioxidants into them. Three local and three internationally manufactured sunscreens were tested for the in vitro Ultraviolet A protection factor (UVAPF), Sun Protection Factor (SPF) and photostability. The creams were spread onto roughened polymethylmethacrylate plates where the absorbance was measured using a spectrophotometer before and after two hours of sunlight irradiation. The procedure was repeated combining available concentrated vitamin C and E creams. International sunscreens were found to have more accurate SPF labels (p=0.009) while local sunscreens were found to be more photostable (p=0.003). However, both sunscreens had inadequate UVAPF (p=0.471). Vitamin C enhanced the SPF values (p= 0.04) of both groups of sunscreens while vitamin E enhanced their photostability (p=0.000). Interestingly, combining vitamins C and E rich creams with the sunscreens had no effect on the SPF and UVAPF values as compared to the use of a single vitamin. More importantly, the combination of vitamins decreased the photostability (p=0.002) of sunscreens as compared to the addition of vitamin E alone. In conclusion, photoprotection is best achieved when sunscreens are used together with creams containing either vitamin C or E alone.

Matched MeSH terms: Polymethyl Methacrylate
Fulltext Simultaneous Co(II)-Titanium(IV) substitution in magnetoplumbite-type barium ferrite nanoparticles

Teh, G.B., Wong, Y.C., Tilley, R.D.

ASM Science Journal, 2014;8(1):21-28.
MyJurnal

Co(II)-Ti(IV)-substituted magnetoplumbite-type (M-type) barium ferrite nanoparticles were synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. Structural and magnetic properties were characterised via X-ray diffraction (XRD), high resolution transmission electron microscopy and superconducting quantum interference device magnetometry. The particle sizes of the M-type BaCoXTiXFe12-2XO19 (0.2 ≤  ≤ 1.0) were found to be 900 Å – 1500 Å. The XRD results confirmed that the Co(II)-Ti(IV) substituted ferrites in the range of 0.2 ≤  ≤ 1.0 substitution had the M-type ferrite as the dominant phase. The hysteresis loss per-cycle decreased with increasing Co(II)-Ti(IV) substitution in M-type ferrites which showed reduced values in coercivity and remnant magnetisation with moderate effect on the saturation magnetisation.

Matched MeSH terms: Polymethyl Methacrylate

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