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Fulltext Investigations on the Mechanical Properties of Glass Fiber/Sisal Fiber/Chitosan Reinforced Hybrid Polymer Sandwich Composite Scaffolds for Bone Fracture Fixation Applications

Arumugam S, Kandasamy J, Md Shah AU, Hameed Sultan MT, Safri SNA, Abdul Majid MS, et al.

Polymers (Basel), 2020 Jul 06;12(7).
PMID: 32640502 DOI: 10.3390/polym12071501

This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications. The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as the inner layers. The composite plate resembles the human bone structure (spongy internal cancellous matrix and rigid external cortical). The mechanical properties of the prepared hybrid sandwich composites samples were evaluated using tensile, flexural, micro hardness, and compression tests. The scanning electron microscopic (SEM) images were studied to analyze the failure mechanism of these composite samples. Besides, contact angle (CA) and water absorption tests were conducted using the sessile drop method to examine the wettability properties of the SF/CTS/epoxy and GF/SF/CTS/epoxy composites. Additionally, the porosity of the GF/SF/CTS composite scaffold samples were determined by using the ethanol infiltration method. The mechanical test results show that the GF/SF/CTS hybrid composites exhibit the bending strength of 343 MPa, ultimate tensile strength of 146 MPa, and compressive strength of 380 MPa with higher Young's modulus in the bending tests (21.56 GPa) compared to the tensile (6646 MPa) and compressive modulus (2046 MPa). Wettability study results reveal that the GF/SF/CTS composite scaffolds were hydrophobic (CA = 92.41° ± 1.71°) with less water absorption of 3.436% compared to the SF/CTS composites (6.953%). The SF/CTS composites show a hydrophilic character (CA = 54.28° ± 3.06°). The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future.

Matched MeSH terms: Hardness
Fulltext EFFECT OF DIFFERENT RATIOS OF LOW PROTEIN FLOUR TO OYSTER MUSHROOM (Pleurotus sajor-caju) POWDER ON THE PHYSICOCHEMICAL PROPERTIES AND SENSORY ACCEPTABILITY OF EDIBLE TABLESPOON

Au Jee Yuan, Faridah Yahya

UMT Journal of Undergraduate Research, 2020;2(1):37-46.
MyJurnal

The aim of this study was to determine the effect of different ratios of low protein flour to oyster mushroom (Pleurotus sajor-caju) powder on the physicochemical properties and sensory acceptability of edible tablespoon. Fresh grey oyster mushroom was dried in a convection oven at temperature of 55.0˚C ± 2.0˚C for 20 h prior to the grinding process. The low protein flour (LPF) was then incorporated with oyster mushroom powder (OMP) at different ratios of 100:0, 96:4, 92:8, 88:12 and 84:16, before being with vegetable oil, sugar, egg white and water in formulating the edible tablespoon. The proximate analyses were carried out in triplicate for calorie content, colour profile, hardness value and morphological structure of edible tablespoon. This study revealed that with decreasing LPF and increasing OMP in the formulation, the ash content (1.24% to 1.92%), crude fat content (8.98% to 10.40%) and fiber content (0.13% to 1.24%) were observed to have increased as well as the hardness value (2042.03g to 2844.57g) and pore’s size of the morphological structure of edible tablespoon. However, the carbohydrate content (78.64% to 75.56%) significantly decreased (p>0.05) together with L* value (from 68.47 to 61.71) when the decrease was in the the percentage of LPF and an increase the percentage of OMP. The calorie content, moisture content and protein content of edible tablespoon were not significantly (p>0.05) affected by different ratios of LPF to OMP. The edible tablespoon formulated with up to 8% of OMP was accepted by the sensory panelists but further increase in OMP addition significantly decreased the degree of likeness in terms of colour, odour, taste and overall acceptability of edible tablespoon. This study suggested that oyster mushroom edible tablespoon could be potential alternative disposable cutlery which will help to reduce the use of huge amount of non-biodegradable materials for environmental conservation.

Matched MeSH terms: Hardness
Fulltext Physicochemical Properties, Nutritional Composition and Sensory Acceptance of Chicken Meat Sausages with Chia Seed Powder Substitution

Nurhani Fatihah Mohd Hanifah, Hanis Nadia Yahya, Norlelawati Arifin

Malaysian Journal of Science, Health & Technology, 2021;7(1):34-42.
MyJurnal

Chia seed has a high content of fibres and polyunsaturated fatty acids. Chia seed also holds numerous amounts of minerals and vitamins, including calcium and phosphorus. Chia seed offers a great potential of gel-forming ability and good water and oil holding capacities. Therefore, this study aims to determine the effect of chia seed powder substitution in chicken meat sausage formulations on the physicochemical characteristics and sensory acceptance. In the study, the chicken meat sausages were produced in four formulations; sample A as the control (100% chicken meat), sample B (5% substitution of chia seed powder to chicken meat), sample C (10% substitution of chia seed powder to chicken meat) and sample D (15% substitution of chia seed powder to chicken meat). The sausages were analysed for colour, texture, water holding capacity, cooking loss, proximate analysis, crude fibre content, and sensory acceptability. As for the findings, the substitution of chia seed powder resulted in low ‘L’ values of chicken meat sausage due to the dark colour of the chia seed. On the other hand, chia seed powder's substitution decreased the hardness and cohesiveness values. However, it increased the adhesiveness, springiness, and chewiness. Water holding capacity and a cooking loss percentage of the chicken meat sausages with chia seed powder substitution were observed to improve compared to control sausage (100% chicken meat), resulting in juicier sausages. The chia seed powder substitution increased the carbohydrate, ash, fat, and fibre contents for the chemical composition. On a 9-point hedonic scale, sample B (5% chia seed powder substitution) exhibited the highest sensory scores in all attributes evaluated (colour, texture, taste, juiciness, and overall acceptance). Thus, it can be concluded that chia seed powder can be substituted in chicken meat sausage to produce better quality products.

Matched MeSH terms: Hardness
Fulltext Effect of different hydrocolloids on the physicochemical properties, microbiological quality and sensory acceptance of fermented cassava ( tapai ubi ) ice cream

Halim, N.R.A., Shukri, W.H.Z., Lani, M.N., Sarbon, N.M.

International Food Research Journal, 2014;21(5):1825-1836.
MyJurnal

The aim of this work is to study the effect of hydrocolloids; guar gum (GG), xanthan gum (XG) and carboxymethyl cellulose (CMC) on the physicochemical properties, microbiological quality and sensory properties in order to investigate the potential of applying fermented cassava (tapai ubi) in ice cream. Fermented cassava ice cream (FCI) incorporated with the three types of hydrocolloid was prepared and the protein content, pH value, overrun, colour, hardness, microstructure, FTIR spectrum and sensory acceptance of all samples were determined. Fermented cassava ice cream incorporated with XG showed the highest protein content (14.88%), pH value (pH 6.07), and overrun value (4.27%) as compared to the fermented cassava ice cream incorporated with GG and CMC. Meanwhile, ice cream incorporated with GG possessed the highest L* (94.43) and hardness (3693.15 g) value as compared to XG and CMC. The microstructure study showed that the difference in uniformity at the interface obtained with different types of the hydrocolloids added demonstrated the effect of fat absorption at the air interfaces. The FTIR spectrum investigated indicated that the addition of the fermented cassava to FCI had increased the OH group in the ice cream as compared to the control. All samples were microbial safe as the total plate counts in all samples were below the standard as prescribed in Food Act 1983 with no presence of E. coli . In conclusion, fermented cassava ice cream with XG showed the good quality in terms of its pH value, overrun, total plate count and overall acceptability.

Matched MeSH terms: Hardness
Fulltext Effects of resin cements on hardness and thickness around titanium post: an intraradicular assessment

Lim, Siau Peng, Fazal Reza, Zaihan Ariffin

Archives of Orofacial Sciences, 2011;6(2):1-10.
MyJurnal

The purpose of this study was to evaluate hardness (indicator for polymerization) and thickness of two types of resin cement at coronal, middle and apical level of tooth root canal. Ten extracted maxillary incisors were instrumented and post space was prepared for cementation of titanium post. Samples were divided into two groups and each group was cemented either of the two types of resin cements; Panavia F [dual-cured (PF)] and Rely X Luting 2 [self-cured (RL)]. The teeth were longitudinally sectioned; hardness and thickness was measured using Vickers hardness tester and a microscope (Leica DMLM). SEM observations along the cement line at the 3 different root levels were performed. Statistical analysis was performed to test significance of differences in hardness and thickness of the two types of cement (t-test; p= 0.05) and at different levels of the same type (one-way ANOVA followed by multiple comparison; p= 0.05). Significant difference of hardness was found at the apical level between the two groups and between the coronal and apical level of PF (p0.05). Moreover, voids were more obvious within the dual-cured group of cement. Dual-cured resin cement was found to be less polymerized than self-cured type at apical level. Increased thicknesses of resin cements in comparison to post space size were observed in both groups. Use of metallic post with resin cements needs further evaluation.

Matched MeSH terms: Hardness
Fulltext Quality evaluation of steamed wheat bread substituted with green banana flour

Noor Aziah, A. A., Ho, L. H., Noor Shazliana, A. A., Rajeev, B.

International Food Research Journal, 2012;19(3):869-876.
MyJurnal

Quality attributes of steamed bread without green banana flour (BF) (CON), substituted with 30%
BF (BBFI) and 30% BF + 8% gluten (BBFII) were determined. The green banana flour (BF) and the mixture of wheat flour (WF) substituted with 30% BF + 8% gluten (FBFII) was significantly highest in water holding capacity and oil holding capacities, respectively. Potassium, calcium and magnesium were significantly higher in BBFI and BBFII than CON. Significantly highest insoluble dietary fibre and total dietary fibre shown in BBFI. Steaming resulted significant reduction in resistant starch content in BBFI as compared with the dough of BBFI I. The specific volume of BBFII and CON showed significant different compared to the BBFI. The BBFII spread ratio was significantly highest and steamer spring lowest than CON. BBFII showed significantly highest in hardness and adhesiveness values but CON was significantly highest in cohesiveness, elasticity and chewiness. L and Hue values was shown highest in CON. BBFII indicated highest acceptability score than other samples.

Matched MeSH terms: Hardness
Fulltext Effects of two cycle heat treatment on the microstructure and hardness of Ductile Iron

Mohd Faizul Idham, Bulan Abdullah, Khalissah Muhammad Yusof

Pertanika Journal of Science & Technology, 2017;25(103):99-106.
MyJurnal

Austempering is one of the trendiest heat treatment processes to promote the strength and toughness of ductile iron. However, such practice is complex because it involves using aqueous solutions as quenchant (salt bath solution). This study was conducted to analyse the heat treatment of the combination processes of annealing-austenitising and evaluate the correlation between microstructure constituent and hardness of the ductile iron. Ductile iron samples in form of double cylinder was produced by conventional CO2 sand casting method. The new heat treatment process was started by annealed at 873 K for 1.8 ks before being oil quenched. Subsequently, the samples were austenitised at austenitising temperatures 1123 K, 1173 K and 1223 K for 3.6 ks respectively before being immediately oil quenched to room temperature. A series of microstructure analysis tests, including optical microscopy and X-ray diffraction (XRD) was applied. Vickers microhardness tester was used to measure the hardness for each microstructure constituent. The results showed that ductile iron matrix transforms to martensitic during heat treatment of annealing-austenitising combination processes, which in turn contributes to increasing microhardness of martensite and the bulk hardness of ductile iron.

Matched MeSH terms: Hardness
Fulltext Development and evaluation of Ketoprofen sustained release matrix tablet using Hibiscus rosa-sinensis leaves mucilage

Kaleemullah M, Jiyauddin K, Thiban E, Rasha S, Al-Dhalli S, Budiasih S, et al.

Saudi Pharm J, 2017 Jul;25(5):770-779.
PMID: 28725150 DOI: 10.1016/j.jsps.2016.10.006

Currently, the use of natural gums and mucilage is of increasing importance in pharmaceutical formulations as valuable drug excipient. Natural plant-based materials are economic, free of side effects, biocompatible and biodegradable. Therefore, Ketoprofen matrix tablets were formulated by employing Hibiscus rosa-sinensis leaves mucilage as natural polymer and HPMC (K100M) as a synthetic polymer to sustain the drug release from matrix system. Direct compression method was used to develop sustained released matrix tablets. The formulated matrix tablets were evaluated in terms of physical appearance, weight variation, thickness, diameter, hardness, friability and in vitro drug release. The difference between the natural and synthetic polymers was investigated concurrently. Matrix tablets developed from each formulation passed all standard physical evaluation tests. The dissolution studies of formulated tablets revealed sustained drug release up to 24 h compared to the reference drug Apo Keto® SR tablets. The dissolution data later were fitted into kinetic models such as zero order equation, first order equation, Higuchi equation, Hixson Crowell equation and Korsmeyer-Peppas equation to study the release of drugs from each formulation. The best formulations were selected based on the similarity factor (f2) value of 50% and more. Through the research, it is found that by increasing the polymers concentration, the rate of drug release decreased for both natural and synthetic polymers. The best formulation was found to be F3 which contained 40% Hibiscus rosa-sinensis mucilage polymer and showed comparable dissolution profile to the reference drug with f2 value of 78.03%. The release kinetics of this formulation has shown to follow non-Fickian type which involved both diffusion and erosion mechanism. Additionally, the statistical results indicated that there was no significant difference (p > 0.05) between the F3 and reference drug in terms of MDT and T50% with p-values of 1.00 and 0.995 respectively.

Matched MeSH terms: Hardness
Fulltext Fermented Brown Rice Flour as Functional Food Ingredient

Ilowefah M, Chinma C, Bakar J, Ghazali HM, Muhammad K, Makeri M

Foods, 2014 Feb 12;3(1):149-159.
PMID: 28234309 DOI: 10.3390/foods3010149

As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker's yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to obtain fermented brown rice flour (FBRF). The FBRF was added to white rice flour at 0%, 10%, 20%, 30%, 40% and 50% levels to prepare steamed rice bread. Based on the sensory evaluation test, steamed rice bread containing 40% FBRF had the highest overall acceptability score. Thus, pasting properties of the composite rice flour, rheological properties of its batter, volume and texture properties of its steamed bread were determined. The results showed that peak viscosity of the rice flour containing 40% FBRF was significantly increased, whereas its breakdown, final viscosity and setback significantly decreased. Viscous, elastic and complex moduli of the batter having 40% FBRF were also significantly reduced. However, volume, specific volume, chewiness, resilience and cohesiveness of its steamed bread were significantly increased, while hardness and springiness significantly reduced in comparison to the control. These results established the effectiveness of yeast fermentation in reducing the detrimental effects of bran on the sensory properties of steamed white rice bread and encourage the usage of brown rice flour to enhance the quality of rice products.

Matched MeSH terms: Hardness
Fulltext 3D Printing of UV-Curable Polyurethane Incorporated with Surface-Grafted Nanocellulose

Mohan D, Sajab MS, Kaco H, Bakarudin SB, Noor AM

Nanomaterials (Basel), 2019 Dec 03;9(12).
PMID: 31817002 DOI: 10.3390/nano9121726

The recognition of nanocellulose has been prominent in recent years as prospect materials, yet the ineffectiveness of nanocellulose to disperse in an organic solvent has restricted its utilization, especially as a reinforcement in polymer nanocomposite. In this study, cellulose has been isolated and defibrillated as cellulose nanofibrils (CNF) from oil palm empty fruit bunch (EFB) fibers. Subsequently, to enhance its compatibility with UV-curable polyurethane (PU)-based resin, the surface hydrophilicity of CNF has been tailored with polyethylene glycol (PEG), as well as reduced graphene oxide (rGO). The dispersibility of reinforced modified CNF in UV-curable PU was examined through the transmittance interruption of resin, chemical, and mechanical properties of the composite printed using the stereolithographic technique. Evidently, the enhanced compatibility of modified CNF and UV-curable PU was shown to improve the tensile strength and hardness of the composites by 37% and 129%, respectively.

Matched MeSH terms: Hardness
ENR-50 compatibilized natural rubber/recycled acrylonitrile-butadiene rubber blends

Hazwani Syaza Ahmad, Hanafi Ismail, Azura Abd Rashid

Sains Malaysiana, 2015;44:835-842.

Epoxidized natural rubber (ENR-50) has been used as a compatibilizer for natural rubber-recycled acrylonitrile-butadiene
rubber (NR/NBRr) blends, vulcanized by sulfur. NBR gloves have excellent resistance to punctures, tear and many types
of chemicals, while NR has good physical and mechanical properties. Incorporation of ENR-50 into the rubber blends
has improved processability, stiffness, resilience and excellent oil resistance. NR/NBRr blends were prepared by two-roll
mill with five different compositions with the ENR-50 content fixed at 10 phr. Cure characteristics, mechanical properties
and morphology (SEM) studies were performed to determine the compatibility of NR/NBRr blends in the presence of ENR-
50. The cure characteristics showed that NR/NBRr blends with the presence of ENR-50 have lower scorch time (ts2) and
cure time (t90) than NR/NBRr blends without ENR-50. However, the NR/NBRr blends with ENR-50 exhibited higher minimum
torque (ML
) and maximum torque (MH) which indicated difficult processability of the blends after compatibilization.
Incorporation of ENR-50 into NR/NBRr blends improved all the tensile properties (tensile strength, tensile modulus and
elongation at break) compared with NR/NBRr blends without ENR-50. The improvement in hardness upon compatibilization
is due to an increase in crosslink density. Scanning electron microscopy (SEM images) of the fracture surfaces indicates
that, with the addition of ENR-50 in NR/NBRr blends, better adhesion between NR and NBRr was obtained, thus improving
the compatibility of NR/NBRr blends.

Matched MeSH terms: Hardness
Muscle spindles provide servo-assistance to jaw-closing muscles for chewing hard foods

Zakir H, Fathilah A, Bakri M, Kitagawa J

Sains Malaysiana, 2015;44:593-597.

The fundamental pattern of chewing induced by the network of neurons called central pattern generator has been reported
to be modified by the information arising from the various oro-facial sensory receptors including muscle spindles of jaw
closing muscles. The cell bodies of primary afferent neurons from these muscle spindles lie in mesencephalic trigeminal
nucleus (MTN) in the brainstem. The aim of the study was to understand whether muscle spindles from jaw-closing
muscles play any role in hard food chewing. Single neuronal discharge of muscle spindle afferents was recorded from the
MTN simultaneous with jaw-movement and electromyograpic (EMG) activities of the left masseter (jaw-closing) muscle
during chewing soft and hard foods (apple and pellet) in awake rabbits. Ten consecutive chewing cycles were taken for
analysis. Discharge of nineteen muscle spindles from seven rabbits was successfully recorded. Muscle-spindle discharge
was significantly higher during the closing phase of jaw-movement for the hard food chewing than for the soft food. The
jaw-closing muscle EMG activity was significantly higher during hard food chewing compared to soft food. The spindle
discharge was higher when the masseter muscle activity was greater for chewing hard food. Significant positive (r=0.822,
p=<0.001) correlation was found between the difference of muscle activity between apple and pellet and the difference
of spindle discharge between apple and pellet. Above findings suggest that the increase of spindle discharge during
hard food chewing may play a role for facilitating jaw-closing muscle activities and thereby provides servo-assistance
to jaw-closing muscles to compensate the hardness of food.

Matched MeSH terms: Hardness
Quantity and quality of groundwater in fractured metasedimentary rocks of the west coast of Peninsular Malaysia

Nasiman Sapari, Hisyam Jusoh, Raja Zainariah Raja Azie

Sains Malaysiana, 2011;40:1179-1186.

Groundwater in fractured metasedimentary rock in Malaysia is a potential source of water for drinking and industrial uses. Industries including agricultural processing, mineral water bottling, manufacturing and golf courses pumped the water from the underlying fractured rocks. Fifty eight tubewells belong to private companies operating in various places in West Coast of Peninsular Malaysia were evaluated for their yield and quality of water. Rotary percussion methods were used for the drilling to a maximum depth of 200 m. The productivity of the wells and the characteristics of the aquifer were evaluated by pumping test using both the constant discharge rate and steps drawdown methods. The average yield of the wells at allowable drawdown of 40 m was found to be 416 m3 per day. Results from water quality analysis indicated that the water was fresh with an average total dissolved solids (TDS) concentration of 101 to 150 mg/L. The hardness of the water varies from as low as 13 mg/L to a maximum of 353 mg/L. On the average, the water was moderately hard with the average hardness value of 80 mg/L. The water facies of the groundwater was found to be of calcium-sodium-bicarbonate water.

Matched MeSH terms: Hardness
Fulltext Nonprescription Bleaching versus Home Bleaching with Professional Prescriptions: Which One is Safer? A Comprehensive Review of Color Changes and Their Side Effects on Human Enamel

Omar F, Ab-Ghani Z, Rahman NA, Halim MS

Eur J Dent, 2019 Oct;13(4):589-598.
PMID: 31891975 DOI: 10.1055/s-0039-1700659

OBJECTIVES: This study evaluates the efficacy and safety of the professionally prescribed and nonprescription over-the-counter (OTC) bleaching agents.
MATERIALS AND: METHODS: Extracted human upper central incisors were prepared and stained with red wine for 14 days before being subjected to four different bleaching agents: professionally prescribed opalescence PF 15%, VOCO Perfect Bleach 10%, nonprescription OTC Crest 3D Whitestrips, and Whitelight Teeth Whitening System. Colorimetric measurement was performed with Vita Easyshade Handheld Spectrophotometer, enamel surface microhardness measured using Vickers Hardness machine, and surface roughness was evaluated with profilometer, before and after bleaching. Scanning electron microscope (SEM) evaluation and atomic force microscopy were conducted postbleaching.
STATISTICAL ANALYSIS: The data were analyzed with t-test, two-way ANOVA, one-way ANOVA, and Turkey's test at a significance level of 5%.
RESULTS: All bleaching products have the same efficacy to whiten stained enamel. Opalescence PF 15% showed significant increase in the microhardness (92.69 ± 68.316). All groups demonstrated significant increase in surface roughness (p < 0.05). SEM evaluation showed that Opalescence PF 15% resulted in same microscopic appearance as unbleached enamel, while VOCO Perfect Bleach 10%, Whitelight Teeth Whitening System and Crest 3D Whitestrips demonstrated mild to moderate irregularities and accentuated irregularities, respectively.
CONCLUSION: Professionally prescribed bleaching agent of Opalescence PF 15% is effective tin whitening the teeth, while the other bleaching products may be effective but also have deleterious effects on the enamel.

Matched MeSH terms: Hardness
Assessment of masticatory performance by geometric measurement of the mixing ability with 2-color chewing gum

Yousof Y, Salleh NM, Yusof F

J Prosthet Dent, 2019 Jun;121(6):916-921.
PMID: 30745100 DOI: 10.1016/j.prosdent.2018.09.005

STATEMENT OF PROBLEM: The 2-color mixing ability test has been recently introduced for objective assessment of masticatory performance. However, the ideal bicolor specimens have not yet been identified, and the color analysis of digital images requires improvement.
PURPOSE: The purpose of this clinical study was to formulate a custom-made, 2-color chewing gum for the mixing ability test and to develop an image-processing method for color mixing analysis.
MATERIAL AND METHODS: Specimens of red-green (RG) chewing gum were prepared as a test food. Twenty dentate participants (10 men, 10 women; mean age 21 years) took part in this study. Each participant masticated 1 piece of RG gum for 3, 6, 9, 15, and 25 cycles, and this task was repeated 3 times consecutively (total n=15 for each participant). The boluses were retrieved and flattened to 1-mm-thick wafers and scanned with a flatbed scanner. The digital images were analyzed using ImageJ software equipped with a custom-built plug-in to measure the geometric dispersion (GD) of baseline red segment. The predictive criterion validity of this method was determined by correlating GD to the number of mastication cycles. The hardness and mass of RG chewing gum were measured before and after mastication. Hardness loss (%) and mass loss (%) were then calculated and compared with those of a commercially available chewing gum.
RESULTS: The 2-way repeated-measures ANOVA with post hoc Bonferroni test showed that GD was able to discriminate among the groups of different numbers of mastication cycles (P

Matched MeSH terms: Hardness
Comparison of Disintegrant-addition Methods on the Compounding of Orodispersible Tablets

Mahesparan VA, Bin Abd Razak FS, Ming LC, Uddin AH, Sarker MZI, Bin LK

Int J Pharm Compd, 2020 3 21;24(2):148-155.
PMID: 32196477

Orodispersible tablets disintegrate rapidly (within 3 minutes) in the oral cavity and release the medicament before swallowing. The mode of disintegrant addition might affect the properties of orodispersible tablets. The objective of this study was to formulate and evaluate orodispersible tablets by studying different modes of disintegration addition with varying concentrations of disintegrants. The wet granulation method was used to produce the orodispersible tablets. Two methods of disintegration addition were compared (i.e., intragranular, extragranular). Three disintegrants (i.e., cornstarch, sodium starch glycolate, crospovidone) were used at three levels (5%, 10%, and 15%) in the study. The formulations were tested for the powder flowability (angle of repose) and characterized physically (hardness, weight, thickness, friability, disintegration time). The mangosteen pericarp extract was used as a model active pharmaceutical ingredient to be incorporated into the optimum formulation. It was observed that the extragranular method produced granules with better flowability compared to that of the intragranular method. Crospovidone was found as the most efficient disintegrant among the three. The optimum formulation selected was one with the highest concentration of crospovidone (15%), which showed the fastest disintegration time. The mode of disintegrant addition into the orodispersible tablets formulation was found to show a marked difference in the disintegration, as well as other physical characteristics of the orodispersible tablets where the extragranular mode of addition showed better property, which caused the orodispersible tablets to disintegrate the fastest.

Matched MeSH terms: Hardness
Study on the relation between mineral compositions of rock and construction characteristics of tunnel in cold regions: a case

Yanliang shang, Shouji du, Honghong gao, Tongyin han

Sains Malaysiana, 2017;46:2241-2250.

Mineral composition of rock has a very important influence on the physical and mechanical properties of tunnel surrounding rock. Take Dangjianshan tunnel in cold regions for example, the rock specimens in different parts of tunnel were taken to carry out the detection test of mineral composition. By the detail qualitative and quantitative analysis, the relationship between mineral composition and surrounding rock engineering properties was explored. First of all, the composition and content of minerals contained in in the rock specimens were detected by X ray fluorescence spectrometer and X ray powder diffraction. The detection results show that rock of tunnel contains high hardness minerals such as quartz and feldspar which were proven by initial engineering geological investigation report, in addition, it also contains several kinds of low hardness minerals including inclined chlorite and illite which may exhibit large deformation characteristic of soft rock after the tunnel excavation in case of meeting water and weathering conditions. The total content of inclined chlorite and illite accounted for a considerable component in main tunnel, inclined shaft and parallel pilot respectively and the influence on surrounding rock engineering properties cannot be ignored. Therefore, mineral composition detection must be paid attention to after tunnel excavation. Secondly, the effects of mineral composition on surrounding rock were analyzed in aspects of rock strength, weathering resistance, water softening property and excavation deformation through comparing the rock samples in different parts of tunnel. The comparative results showed that when the mineral contents is high with high hardness and poor hydrophilicity, tunnel surrounding rock plays a better performance of physical and mechanical properties, vice versa. Finally, according to the specific geological and construction parameters of the tunnel, the correlation analysis was studied about the vault settlement after tunnel excavation and the hydrophilicity mineral content in main cave. The logarithmic relationship between them was found and the correlation coefficient was 0.98. It can provide a useful reference for the settlement prediction of Dangjinshan tunnel construction.

Matched MeSH terms: Hardness
Effect of various infection-control methods for light-cure units on the cure of composite resins

Chong SL, Lam YK, Lee FK, Ramalingam L, Yeo AC, Lim CC

Oper Dent, 1998 Mar-Apr;23(3):150-4.
PMID: 9656927

This study (1) compared the curing-light intensity with various barrier infection-control methods used to prevent cross contamination, (2) compared the Knoop hardness value of cured composite resin when various barrier control methods were used, and (3) correlated the hardness of the composite resin with the light-intensity output when different infection-control methods were used. The light-cure unit tips were covered with barriers, such as cellophane wrap, plastic gloves, Steri-shields, and finger cots. The control group had no barrier. Composite resins were then cured for each of the five groups, and their Knoop hardness values recorded. The results showed that there was significant statistical difference in the light-intensity output among the five groups. However, there was no significant statistical difference in the Knoop hardness values among any of the groups. There was also no correlation between the Knoop hardness value of the composite resin with the light-intensity output and the different infection-control methods. Therefore, any of the five infection-control methods could be used as barriers for preventing cross-contamination of the light-cure unit tip, for the light-intensity output for all five groups exceeded the recommended value of 300 W/m2. However, to allow a greater margin of error in clinical situations, the authors recommend that the plastic glove or the cellophane wrap be used to wrap the light-cure tip, since these barriers allowed the highest light-intensity output.

Matched MeSH terms: Hardness
Fulltext Multi-Objective Optimization of Friction Stir Welding Process Parameters of AA6061-T6 and AA7075-T6 Using a Biogeography Based Optimization Algorithm

Tamjidy M, Baharudin BTHT, Paslar S, Matori KA, Sulaiman S, Fadaeifard F

Materials (Basel), 2017 May 15;10(5).
PMID: 28772893 DOI: 10.3390/ma10050533

The development of Friction Stir Welding (FSW) has provided an alternative approach for producing high-quality welds, in a fast and reliable manner. This study focuses on the mechanical properties of the dissimilar friction stir welding of AA6061-T6 and AA7075-T6 aluminum alloys. The FSW process parameters such as tool rotational speed, tool traverse speed, tilt angle, and tool offset influence the mechanical properties of the friction stir welded joints significantly. A mathematical regression model is developed to determine the empirical relationship between the FSW process parameters and mechanical properties, and the results are validated. In order to obtain the optimal values of process parameters that simultaneously optimize the ultimate tensile strength, elongation, and minimum hardness in the heat affected zone (HAZ), a metaheuristic, multi objective algorithm based on biogeography based optimization is proposed. The Pareto optimal frontiers for triple and dual objective functions are obtained and the best optimal solution is selected through using two different decision making techniques, technique for order of preference by similarity to ideal solution (TOPSIS) and Shannon's entropy.

Matched MeSH terms: Hardness
Fulltext Comparative evaluation of application of different fluoride varnishes on artificial early enamel lesion: An in vitro study

Majithia U, Venkataraghavan K, Choudhary P, Trivedi K, Shah S, Virda M

Indian J Dent Res, 2016 Sep-Oct;27(5):521-527.
PMID: 27966511 DOI: 10.4103/0970-9290.195642

INTRODUCTION: In an attempt to manage noncavitated carious lesions noninvasively through remineralization, a range of novel fluoride varnishes with additional remineralizing agents have been made available for clinical application.

AIM AND OBJECTIVES: The aim of this study was to compare and evaluate the remineralization potential of three commercially available varnishes on artificial enamel lesions.

MATERIALS AND METHODS: This in vitro study involves eighty intact enamel specimens prepared from premolars extracted for orthodontic purposes. After specimen preparation, the eighty samples were divided randomly into two groups (n = 40) for measurement of baseline surface Vickers microhardness and baseline calcium/phosphorus ratio (% weight) through EDAX testing. Thereafter, the specimens were subjected to demineralization for 96 h to induce initial enamel lesions and the measurements were repeated. Following demineralization, each of the two groups was divided randomly into four subgroups (n = 10) from which one was used as the control group and the others three were allotted to each of the three test varnishes. After varnish application, all the specimens were subjected to a pH cycling regimen that included alternative demineralization (3 h) and remineralization (21 h) daily, for 5 consecutive days. The Vickers microhardness and EDAX measurements were then repeated.

RESULTS: One-way ANOVA and post hoc Tukey's tests were conducted for multiple group comparison. All the three commercially available varnishes were capable of remineralizing initial enamel lesions that were induced artificially. No difference was noted in the remineralizing efficacy of the varnishes despite their different compositions. MI Varnish™ (casein phosphopeptide-amorphous calcium phosphate fluoride varnish) showed slightly better recovery in surface microhardness as compared to the other two varnishes.

CONCLUSION: All the varnishes used in this in vitro study are capable of reversing early enamel lesions.

Matched MeSH terms: Hardness/drug effects

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