Displaying publications 1 - 20 of 141 in total

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  1. Rajeev V, Arunachalam R, Nayar S, Arunima PR, Ganapathy S, Vedam V
    Eur J Dent, 2017 4 25;11(1):58-63.
    PMID: 28435367 DOI: 10.4103/ejd.ejd_113_16
    OBJECTIVE: This in vitro study was designed to assess shear bond strength (SBS) of ormocer flowable (OF) resin as a luting agent, ormocer as an indirect veneer material with portrayal of modes of failures using scanning electron microscope (SEM).

    MATERIALS AND METHODS: Sixty maxillary central incisors were divided into Group I, II, and III with 20 samples each based on luting cement used. They were OF, self-adhesive (SA) cement, and total etch (TE) cement. These groups were subdivided into "a" and "b" of ten each based on the type of veneering materials used. Veneer discs were fabricated using Ormocer restorative (O) and pressable ceramic (C). Specimens were thermocycled and loaded under universal testing machine for SBS. The statistical analysis was done using one-way ANOVA post hoc Tukey honest significant difference method.

    RESULTS: A significant difference was observed between the Groups I and II (P < 0.05). The highest mean bond strength when using ormocer veneer was obtained with the Group Ia (19.11 ± 1.92 Mpa) and lowest by Group IIa (8.1 ± 1.04 Mpa), whereas the highest mean bond strength while using ceramic veneer was of similar range for Group Ib (18.04 ± 4.08 Mpa) and Group IIIb (18.07 ± 1.40 Mpa). SEM analysis revealed OF and TE presented mixed type of failure when compared with SA where failure mode was totally adhesive.

    CONCLUSION: OF was found equally efficient like TE. Bond strength of ormocer as a veneer was not inferior to ceramic making it one of the promising additions in the field of dentistry.

    Matched MeSH terms: Ceramics; Organically Modified Ceramics
  2. Al-Maqtari AA, Razak AA, Hamdi M
    Dent Mater J, 2014;33(4):458-65.
    PMID: 25087658
    This study aimed at investigating and establishing stress distributions in graded multilayered zirconia/alumina ceramic cores and at veneer-core-cement-dentin interfaces, using finite element analysis (FEA), to facilitate the structural design of ceramic cores through computer modeling. An intact maxillary premolar was digitized using CT scanning. An imaging software, Mimics, was used to reconstruct 3D models based on computed tomography (CT) data saved in DICOM format. Eight different 3D models were created for FEA, where each 3D model was meshed and its bottom boundaries constrained. A static load was applied in the oblique direction. The materials were assumed to be isotropic and homogeneous. Highest von Mises stress values were found in areas directly below the load application point, and stress gradually decreased in occlusal loading direction from the external surface toward the dentin. Stress levels occurring at veneer-ceramic core-cement-dentin interfaces were shown to be lower in multilayered ceramic cores than in single-layer models.
    Matched MeSH terms: Ceramics*
  3. Ullah MH, Islam MT, Faruque MRI
    Materials (Basel), 2013 Nov 06;6(11):5058-5068.
    PMID: 28788376 DOI: 10.3390/ma6115058
    A new meta-surface structure (MSS) with a near-zero refractive index (NZRI) is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating the planar NZRI MSS at the back of the antenna structure. The proposed NZRI MSS-loaded CPW-fed (Co-Planar Waveguide) four-element array antenna is designed on ceramic-bioplastic-ceramic sandwich substrate using high-frequency structure simulator (HFSS), a finite-element-method-based simulation tool. The gain and directivity of the antenna are significantly enhanced by incorporating the NZRI MSS with a 7 × 6 set of elements at the back of the antenna structure. Measurement results show that the maximum gains of the antenna increased from 6.21 dBi to 8.25 dBi, from 6.52 dBi to 9.05 dBi and from 10.54 dBi to 12.15 dBi in the first, second and third bands, respectively. The effect of the slot configuration in the ground plane on the reflection coefficient of the antenna was analyzed and optimized. The overall performance makes the proposed antenna appropriate for UHFFM (Ultra High Frequency Frequency Modulation) telemetry-based space applications as well as mobile satellite, microwave radiometry and radio astronomy applications.
    Matched MeSH terms: Ceramics
  4. Islam MT, Ullah MH, Singh MJ, Faruque MRI
    Materials (Basel), 2013 Jul 31;6(8):3226-3240.
    PMID: 28811432 DOI: 10.3390/ma6083226
    A new metasurface superstrate structure (MSS)-loaded dual band microstrip line-fed small patch antenna is presented in this paper. The proposed antenna was designed on a ceramic-filled bioplastic sandwich substrate with a high dielectric constant. The proposed 7 × 6 element, square-shaped, single-sided MSS significantly improved the bandwidth and gain of the proposed antenna. The proposed MSS incorporated a slotted patch antenna that effectively increased the measured operating bandwidth from 13.3% to 18.8% and from 14.8% to 23.2% in the lower and upper bands, respectively. Moreover, the average gain of the proposed MSS-based antenna was enhanced from 2.12 dBi to 3.02 dBi in the lower band and from 4.10 dBi to 5.28 dBi in the upper band compared to the patch antenna alone. In addition to the bandwidth and gain improvements, more directive radiation characteristics were also observed from the MSS antenna compared to the patch itself. The effects of the MSS elements and the ground plane length on the reflection coefficient of the antenna were analyzed and optimized. The overall performance makes the proposed antenna appropriate for RFID and WLAN applications.
    Matched MeSH terms: Ceramics
  5. Choo TF, Mohd Salleh MA, Kok KY, Matori KA, Abdul Rashid S
    Materials (Basel), 2020 Nov 18;13(22).
    PMID: 33218206 DOI: 10.3390/ma13225218
    Grog is an additive material that plays important roles in ceramic making. It improves the fabrication process of green bodies as well as the physical properties of fired bodies. Few low-cost materials and wastes have found their application as grog in recent years, thus encouraging the replacement of commercial grogs with cost-saving materials. Coal fly ash, a combustion waste produced by coal-fired power plant, has the potential to be converted into grog owing to its small particle sizes and high content of silica and alumina. In this study, grog was derived from coal fly ash and mixed with kaolin clay to produce ceramics. Effects of the grog addition on the resultant ceramics were investigated. It was found that, to a certain extent, the grog addition reduced the firing shrinkage and increased the total porosity of the ceramics. The dimensional stability of the ceramics at a firing temperature of 1200 °C was also not noticeably affected by the grog. However, the grog addition in general had negative effects on the biaxial flexural strength and refractoriness of the ceramics.
    Matched MeSH terms: Ceramics
  6. Tan TJ, Wang D, Moraru CI
    J Dairy Sci, 2014;97(8):4759-71.
    PMID: 24881794 DOI: 10.3168/jds.2014-7957
    The main challenge in microfiltration (MF) is membrane fouling, which leads to a significant decline in permeate flux and a change in membrane selectivity over time. This work aims to elucidate the mechanisms of membrane fouling in cold MF of skim milk by identifying and quantifying the proteins and minerals involved in external and internal membrane fouling. Microfiltration was conducted using a 1.4-μm ceramic membrane, at a temperature of 6±1°C, cross-flow velocity of 6m/s, and transmembrane pressure of 159kPa, for 90min. Internal and external foulants were extracted from a ceramic membrane both after a brief contact between the membrane and skim milk, to evaluate instantaneous adsorption of foulants, and after MF. Four foulant streams were collected: weakly attached external foulants, weakly attached internal foulants, strongly attached external foulants, and strongly attached internal foulants. Liquid chromatography coupled with tandem mass spectrometry analysis showed that all major milk proteins were present in all foulant streams. Proteins did appear to be the major cause of membrane fouling. Proteomics analysis of the foulants indicated elevated levels of serum proteins as compared with milk in the foulant fractions collected from the adsorption study. Caseins were preferentially introduced into the fouling layer during MF, when transmembrane pressure was applied, as confirmed both by proteomics and mineral analyses. The knowledge generated in this study advances the understanding of fouling mechanisms in cold MF of skim milk and can be used to identify solutions for minimizing membrane fouling and increasing the efficiency of milk MF.
    Matched MeSH terms: Ceramics/chemistry
  7. Aytekin K, Esenyel CZ
    Malays Orthop J, 2018 Mar;12(1):45-47.
    PMID: 29725513 DOI: 10.5704/MOJ.1803.010
    Hip arthroplasty is an extremely satisfying treatment method for coxarthrosis which is in increasing use throughout the world. However, loosening of the prosthesis is a significant complication and to overcome this, ceramic liners are increasingly being selected. If the survival of ceramic surfaces is prolonged, there is a risk of fracture of the ceramic materials. New ceramic materials developed to overcome this problem are more resistant. The case presented here is of a patient in whom liner fracture developed following ceramic-ceramic hip arthroplasty. The ceramic femoral head was observed to have protruded into the defect created in the acetabular component. Acetabular revision was applied to the patient.
    Matched MeSH terms: Ceramics
  8. Jhajharia K, Shah HH, Paliwal A, Parikh V, Patel S
    J Clin Diagn Res, 2015 Jun;9(6):ZD28-30.
    PMID: 26266231 DOI: 10.7860/JCDR/2015/12542.6108
    Tooth discolouration is a common problem and affects people of all ages. Apart from the conventional treatment modalities for the same, newer options are available today with better techniques and materials. The present case report describes a 17-year-old girl who had stained and pitted teeth, attributable to dental fluorosis and she desired aesthetic treatment for the same. The pros and cons of all treatment options were carefully weighed and a multistep treatment process involving ceramic veneers and direct bonding were planned. The execution of the planned treatment yielded a good aesthetic and functional outcome.
    Matched MeSH terms: Ceramics
  9. Khan, A., Mohd Noor, N.S., Sukumaran, P., Sheikh Aladin, S.H.A., Wai Ying, Y.
    Ann Dent, 2016;22(2):1-8.
    MyJurnal
    This clinical audit is aimed to provide an insight into the performance of dental technicians in rendering
    fixed prosthodontics services at Faculty of Dentistry, University of Malaya. A retrospective audit was
    carried out between 1st of November 2014 and 31st January 2015 using data derived from records and
    monthly returns of the technicians, which are kept at the ceramic laboratory. Retrospective data on
    cases of diagnostic wax-ups, full metal crowns, metal ceramic crowns, all ceramic crowns and bridges
    that were sent to ceramic laboratory for fabrication from 1st of September 2013 to 31st of August 2014
    was systematically extracted from the record and tabulated categorically in SPSS version 22.0. The
    turnaround time in workings day for diagnostic wax-ups and the prostheses was calculated by deducting
    exit date from entry date. Subsequently, the turnaround time and the complexity of cases were categorized
    accordingly. The association of turnaround time and the complexity of the cases was analysed using
    Fisher Exact test with p value < 0.05. Within this time frame, a total of 102 cases of diagnostic waxups,
    36 cases of crown and 18 cases of bridges were fabricated. 57.8% of diagnostic wax-ups were
    completed within 3 days. 100% of 1 unit crown were completed within 7 days and 94.4% of bridges were
    completed within 14 days. There was a significant association of turnaround time and the complexity of
    the cases for diagnostic wax-ups and crowns with p value
    Matched MeSH terms: Ceramics
  10. Idris B, Rusnah M, Reusmaazran YM, Rohaida CH
    Med J Malaysia, 2004 May;59 Suppl B:67-8.
    PMID: 15468822
    Matched MeSH terms: Ceramics/analysis; Ceramics/chemical synthesis*
  11. Akram Hassan, Swaminathan D
    Hydroxyapatite (HA) used for bone replacement is one of the most active areas of ceramic biomaterials research currently. It has been used clinically for the last 20 years due to its excellent biocompatibility, osseoconduction and osseointegration. Many modifications have been done to develop a stronger, tougher and biocompatible ceramic biomaterial because pure HA is brittle. Researchers in Universiti Sains Malaysia had developed this value added HA that is stronger and less brittle compared to pure HA. The objective of this in vitro study was to evaluate the genotoxic characteristic of the value added HA based material by using Bacterial Reverse Mutation Assay (Ames test). The Bacterial Reverse Mutation Assay of HA was performed on Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 and Escherichia coli strain WP2 uvrA using the preincubation method in the presence and absence of an exogenous metabolic activation system. All the bacterial tester strains treated with and without S9 Mix showed no increase of revertant colonies with increase in concentration of test substance for both the dose finding test and the main test. The number of revertant colonies was less than twice that of the solvent control for all the five bacterial strains and this was reproducible for both the dose finding test and the main test. The numbers of revertant colonies in the negative and positive controls were within the background data of our laboratory. In conclusion the results of the tests showed that the value added HA was considered to have no reverse mutagenic potential under the present test conditions.
    Matched MeSH terms: Ceramics
  12. Zeimaran E, Pourshahrestani S, Djordjevic I, Pingguan-Murphy B, Kadri NA, Wren AW, et al.
    J Mater Sci Mater Med, 2016 Jan;27(1):18.
    PMID: 26676864 DOI: 10.1007/s10856-015-5620-2
    Bioactive glasses may function as antimicrobial delivery systems through the incorporation and subsequent release of therapeutic ions. The aim of this study was to evaluate the antimicrobial properties of a series of composite scaffolds composed of poly(octanediol citrate) with increased loads of a bioactive glass that releases zinc (Zn(2+)) and gallium (Ga(3+)) ions in a controlled manner. The antibacterial activity of these scaffolds was investigated against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The ability of the scaffolds to release ions and the subsequent ingress of these ions into hard tissue was evaluated using a bovine bone model. Scaffolds containing bioactive glass exhibited antibacterial activity and this increased in vitro with higher bioactive glass loads; viable cells decreased to about 20 % for the composite scaffold containing 30 % bioactive glass. The Ga(3+) release rate increased as a function of time and Zn(2+) was shown to incorporate into the surrounding bone.
    Matched MeSH terms: Ceramics*
  13. Philip, Y., Mohd Fadzelly, A. B.
    MyJurnal
    Honey is a sweet substance that can be obtain from flower nectar and secretes through transformations process by honey bees. The aim of this study was to compare the antioxidant and anti-cholinesterase activities of 4 wild honey (wild honey produced by different species of bees: Apis cerana, Apis andreniformis, Apis koschevnikovi and Apis nuluensis) collected from the secondary forest and 6 commercial (young and old Mangrove, young and old Upper mountain, Tropical, Potiukan) honey of Sabah, Malaysian Borneo. Antioxidant activities were determined using FRAP (Ferric Reducing Antioxidant Power), DPPH free radical scavenging and ABTS decolourization assays. Acetylcholinesterase inhibition effect was determined by enzyme inhibition method. The results of this study showed that wild honey produced by A.cerana collected from the Acacia tree extracted using 80% methanol displayed the highest DPPH free radical scavenging activity and ABTS decolorization assays. Whereas wild honey produced by A.nuluensis collected from the Chestnut tree extracted using 80% methanol displayed the highest FRAP activity. The wild honey produced by A. nuluensis also displayed the highest acetylcholinesterase properties as the antioxidant compounds contributed to the inhibitory properties of the enzyme. Manuka honey (produced from tea tree) found to be higher in antioxidant and acetylcholinesterase properties as compared to all other samples. The same trend of bioactivity was also observed in absolute methanol extracts. Strong positive correlation was found between antioxidant and acetylcholinesterase activity. Therefore, honey has the potential as natural antioxidant and acetylcholinesterase inhibition sources with promising potential benefits to human’s health.
    Matched MeSH terms: Ceramics
  14. Nor, M. Z. M., Ramchandran, L., Duke, M., Vasiljevic, T.
    MyJurnal
    About 60% of world’s commercial enzyme products are proteases, giving promising opportunity
    to derive such enzymes sustainably from waste sources. Bromelain is a crude protease occurring
    naturally in pineapple, and it possesses properties of benefit for pharmaceutical, medical and food products. The production of bromelain involves a purification stage, normally performed by small-scale conventional operations which lead to high operating cost and low product recovery, while being difficult to scale up and produce polluting by-products. Membrane-based technology offers an alternative to produce high quality purified bromelain in a more efficient and sustainable process. This review identified the current state and future needs for utilising membrane processes for sustainable bromelain production at larger scales. It was found that declining membrane flux due to fouling have been reported, but may be effectively overcome with more appropriate (and advanced) membrane types and/or processing conditions. For example, interactions between macromolecules present in the pineapple derived bromelain mixture (particularly polysaccharides) and the membrane may cause performance limiting fouling, but can be overcome by enzymatic pre-treatment. Membrane fouling can be further reduced by the employment of ceramic membrane filters operating at optimised trans-membrane pressure, cross-flow velocity, feed pH and temperature. Two-stage ultrafiltration together with diafiltration or gas sparging was suggested as a means to reduce fouling and improve enzyme purity. Despite these promising technical findings, the review identified the need for a valid economic assessment to properly guide further work towards purifying bromelain from pineapple waste for sustainable production of commercial proteases.
    Matched MeSH terms: Ceramics
  15. Deja M, Zieliński D, Kadir AZA, Humaira SN
    Materials (Basel), 2021 Mar 09;14(5).
    PMID: 33803424 DOI: 10.3390/ma14051318
    High requirements imposed by the competitive industrial environment determine the development directions of applied manufacturing methods. 3D printing technology, also known as additive manufacturing (AM), currently being one of the most dynamically developing production methods, is increasingly used in many different areas of industry. Nowadays, apart from the possibility of making prototypes of future products, AM is also used to produce fully functional machine parts, which is known as Rapid Manufacturing and also Rapid Tooling. Rapid Manufacturing refers to the ability of the software automation to rapidly accelerate the manufacturing process, while Rapid Tooling means that a tool is involved in order to accelerate the process. Abrasive processes are widely used in many industries, especially for machining hard and brittle materials such as advanced ceramics. This paper presents a review on advances and trends in contemporary abrasive machining related to the application of innovative 3D printed abrasive tools. Examples of abrasive tools made with the use of currently leading AM methods and their impact on the obtained machining results were indicated. The analyzed research works indicate the great potential and usefulness of the new constructions of the abrasive tools made by incremental technologies. Furthermore, the potential and limitations of currently used 3D printed abrasive tools, as well as the directions of their further development are indicated.
    Matched MeSH terms: Ceramics
  16. Al-Makramani BM, Razak AA, Abu-Hassan MI
    J Appl Oral Sci, 2010 Dec;18(6):607-12.
    PMID: 21308292
    Advances in all-ceramic systems have established predictable means of providing metal-free aesthetic and biocompatible materials. These materials must have sufficient strength to be a practical treatment alternative for the fabrication of crowns and fixed partial dentures.

    OBJECTIVES: The aim of this study was to compare the biaxial flexural strength of three core ceramic materials.

    MATERIAL AND METHODS: Three groups of 10 disc-shaped specimens (16 mm diameter x 1.2 mm thickness - in accordance with ISO-6872, 1995) were made from the following ceramic materials: Turkom-Cera Fused Alumina [(Turkom-Ceramic (M) Sdn Bhd, Puchong, Selangor, Malaysia)], In-Ceram (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany) and Vitadur-N (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany), which were sintered according to the manufacturer's recommendations. The specimens were subjected to biaxial flexural strength test in an universal testing machine at a crosshead speed of 0.5 mm/min. The definitive fracture load was recorded for each specimen and the biaxial flexural strength was calculated from an equation in accordance with ISO-6872.

    RESULTS: The mean biaxial flexural strength values were: Turkom-Cera: 506.8 ± 87.01 MPa, In-Ceram: 347.4 ± 28.83 MPa and Vitadur-N: 128.7 ± 12.72 MPa. The results were analyzed by the Levene's test and Dunnett's T3 post-hoc test (SPSS software V11.5.0 for Windows, SPSS, Chicago, IL, USA ) at a preset significance level of 5% because of unequal group variances (P<0.001). There was statistically significant difference between the three core ceramics (P<0.05). Turkom-Cera showed the highest biaxial flexural strength, followed by In-Ceram and Vitadur-N.

    CONCLUSIONS: Turkom-Cera core had significantly higher flexural strength than In-Ceram and Vitadur-N ceramic core materials.

    Matched MeSH terms: Ceramics/chemistry*
  17. Mohd Zain N.S., Tajudin S.S., Mohd Noor S.N.F., Mohamad H.
    MyJurnal
    Thisstudy aim tocharacterize melt-derivedbioactive glass and to determinethe bioactive glass (BG) suitability for dental usagethrough proliferative activity assessment of stem cells from human exfoliated deciduous teeth (SHED)when exposed to bioactive glass conditioned medium. Bioglass 45S5 in mole percentages (46.13% SiO2, 26.91% CaO, 24.35% Na2O and 2.60% P2O5)was synthesizedthrough melt-derived and characterized usingX-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR)to confirm and identify its properties.SHEDwere used to evaluate the biocompatibility of 45S5 by exposing the cells to various concentration of BG-conditioned medium (1-10 mg/ml) using alamarBlue assay. The BG produced has an amorphous structureas shown by XRD analysis. TheSi-O-Si bending, asymmetric Si-O stretching and asymmetricSi-O-Si stretchingbands were observed in the BG structure supporting the presenceof silicate network. For alamarBlue assay, SHED cultured in BG-conditioned medium showed high proliferation rate when subjected to minimal powder content in the DMEM cell culture medium.Hence, it can be concluded that SHED cultured in lower powder content of the BG-conditioned media showedhigh proliferative activity suggesting the potential of the BG for dental usage.
    Matched MeSH terms: Ceramics
  18. Rizwan M, Hamdi M, Basirun WJ
    J Biomed Mater Res A, 2017 Nov;105(11):3197-3223.
    PMID: 28686004 DOI: 10.1002/jbm.a.36156
    Bioglass® 45S5 (BG) has an outstanding ability to bond with bones and soft tissues, but its application as a load-bearing scaffold material is restricted due to its inherent brittleness. BG-based composites combine the amazing biological and bioactive characteristics of BG with structural and functional features of other materials. This article reviews the composites of Bioglass® in combination with metals, ceramics and polymers for a wide range of potential applications from bone scaffolds to nerve regeneration. Bioglass® also possesses angiogenic and antibacterial properties in addition to its very high bioactivity; hence, composite materials developed for these applications are also discussed. BG-based composites with polymer matrices have been developed for a wide variety of soft tissue engineering. This review focuses on the research that suggests the suitability of BG-based composites as a scaffold material for hard and soft tissues engineering. Composite production techniques have a direct influence on the bioactivity and mechanical behavior of scaffolds. A detailed discussion of the bioactivity, in vitro and in vivo biocompatibility and biodegradation is presented as a function of materials and its processing techniques. Finally, an outlook for future research is also proposed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3197-3223, 2017.
    Matched MeSH terms: Ceramics/metabolism; Ceramics/chemistry*
  19. Gunarajah DR, Samman N
    J Oral Maxillofac Surg, 2013 Mar;71(3):550-70.
    PMID: 23422151 DOI: 10.1016/j.joms.2012.10.029
    To evaluate the reported use and outcomes of implant materials used for the restoration of post-traumatic orbital floor defects in adults.
    Matched MeSH terms: Ceramics
  20. Siti Mariam Ab Ghani, Ahmad Syahir Ahmad Zu Saifudin, Muhammad Aliff Ikram Noor Zari, Teh Adilla Mustaza
    Compendium of Oral Science, 2015;2(1):47-51.
    MyJurnal
    Dental fluorosis incidence had been reported to be affecting children widely, especially in water-fluoridated ar-ea. As these children grow into young adults, perceived aesthetic problems arise mainly due to their concern with generalized mottled and stained teeth appearance. Fixed prosthodontics treatment involving single anterior tooth in patients with generalized fluorosis condition had been found challenging due to aesthetic restorability to blend with fluorosis condition. Clinical considerations: A simplified procedural direct chair-side technique of mimicking fluorosis condition onto anterior all-ceramic crowns are discussed in this paper. The mimicked fluoro-sis is reversible and has the opportunity to be adjusted according to the patient’s fluorosis condition thus hinder-ing the need to redo the crown in the future. Conclusions: The appearance of anterior all-ceramic crowns with direct chair-side staining technique provided blended and harmonized well with the dental fluorosis condition in both patients thus, giving natural looking smile.
    Matched MeSH terms: Ceramics
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