Displaying publications 1 - 20 of 31 in total

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  1. Flexible microfluidic cloth-based analytical devices using a low-cost wax patterning technique
    Nilghaz A, Wicaksono DH, Gustiono D, Abdul Majid FA, Supriyanto E, Abdul Kadir MR
    Lab Chip, 2012 Jan 7;12(1):209-18.
    PMID: 22089026 DOI: 10.1039/c1lc20764d
    This paper describes the fabrication of microfluidic cloth-based analytical devices (μCADs) using a simple wax patterning method on cotton cloth for performing colorimetric bioassays. Commercial cotton cloth fabric is proposed as a new inexpensive, lightweight, and flexible platform for fabricating two- (2D) and three-dimensional (3D) microfluidic systems. We demonstrated that the wicking property of the cotton microfluidic channel can be improved by scouring in soda ash (Na(2)CO(3)) solution which will remove the natural surface wax and expose the underlying texture of the cellulose fiber. After this treatment, we fabricated narrow hydrophilic channels with hydrophobic barriers made from patterned wax to define the 2D microfluidic devices. The designed pattern is carved on wax-impregnated paper, and subsequently transferred to attached cotton cloth by heat treatment. To further obtain 3D microfluidic devices having multiple layers of pattern, a single layer of wax patterned cloth can be folded along a predefined folding line and subsequently pressed using mechanical force. All the fabrication steps are simple and low cost since no special equipment is required. Diagnostic application of cloth-based devices is shown by the development of simple devices that wick and distribute microvolumes of simulated body fluids along the hydrophilic channels into reaction zones to react with analytical reagents. Colorimetric detection of bovine serum albumin (BSA) in artificial urine is carried out by direct visual observation of bromophenol blue (BPB) colour change in the reaction zones. Finally, we show the flexibility of the novel microfluidic platform by conducting a similar reaction in a bent pinned μCAD.
    Matched MeSH terms: Waxes/chemistry*
  2. Bacteria consortia enhanced hydrocarbon degradation of waxy crude oil
    Rahman RNZRA, Latip W, Adlan NA, Sabri S, Ali MSM
    Arch Microbiol, 2022 Nov 12;204(12):701.
    PMID: 36370212 DOI: 10.1007/s00203-022-03316-8
    Waxy crude oil is a problem to the oil and gas industry because wax deposition in pipelines reduces the quality of the crude oil. Currently, the industry uses chemicals to solve the problem but it is not environmentally friendly. As an alternative, the biodegradation approach is one of the options. Previously eleven thermophilic bacteria were isolated and exhibited high ability to degrade hydrocarbon up to 70% of waxy crude oil. However, despite the successful study on these single bacteria strains, it is believed that biodegradation of paraffin wax requires more than a single species. Five consortia were developed based on the biodegradation efficiency of 11 bacterial strains. Consortium 3 showed the highest biodegradation (77.77%) with more long-chain alkane degraded throughout the incubation compared to other consortia. Enhancement of hydrocarbon degradation was observed for all consortia especially in long chain alkane (C18-C40). Consortium 3 exhibited higher alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase activities. Moreover, the dominant bacteria in the consortia were determined by denaturing gradient gel electrophoresis (DGGE), which showed the domination of genera Geobacillus, Parageobacillus, and Anoxybacillus. It can be concluded that the bacterial consortia showed higher biodegradation and improved degrading more long-chain hydrocarbon compared to a single isolate.
    Matched MeSH terms: Waxes/metabolism
  3. Fulltext A review on plant importance, biotechnological aspects, and cultivation challenges of jojoba plant
    Al-Obaidi JR, Halabi MF, AlKhalifah NS, Asanar S, Al-Soqeer AA, Attia MF
    Biol Res, 2017 Aug 24;50(1):25.
    PMID: 28838321 DOI: 10.1186/s40659-017-0131-x
    Jojoba is considered a promising oil crop and is cultivated for diverse purposes in many countries. The jojoba seed produces unique high-quality oil with a wide range of applications such as medical and industrial-related products. The plant also has potential value in combatting desertification and land degradation in dry and semi-dry areas. Although the plant is known for its high-temperature and high-salinity tolerance growth ability, issues such as its male-biased ratio, relatively late flowering and seed production time hamper the cultivation of this plant. The development of efficient biotechnological platforms for better cultivation and an improved production cycle is a necessity for farmers cultivating the plant. In the last 20 years, many efforts have been made for in vitro cultivation of jojoba by applying different molecular biology techniques. However, there is a lot of work to be done in order to reach satisfactory results that help to overcome cultivation problems. This review presents a historical overview, the medical and industrial importance of the jojoba plant, agronomy aspects and nutrient requirements for the plant's cultivation, and the role of recent biotechnology and molecular biology findings in jojoba research.
    Matched MeSH terms: Waxes*
  4. Fulltext Carnauba Wax/Halloysite Nanotube with Improved Anti-Wetting and Permeability of Hydrophobic PVDF Membrane via DCMD
    AbdulKadir WAFW, Ahmad AL, Boon Seng O
    Membranes (Basel), 2021 Mar 23;11(3).
    PMID: 33807017 DOI: 10.3390/membranes11030228
    The hydrophobic membranes have been widely explored to meet the membrane characteristics for the membrane distillation (MD) process. Inorganic metal oxide nanoparticles have been used to improve the membrane hydrophobicity, but limited studies have used nano clay particles. This study introduces halloysite nanotube (HNT) as an alternative material to synthesis a hydrophobic poly(vinylidene fluoride) (PVDF)-HNT membrane. The PVDF membranes were fabricated using functionalized HNTs (e.g., carnauba wax and 1H,1H,2H,2H-perfluorooctyl-trichlorosilane (FOTS)). The results were determined by Fourier transform infrared-attenuated total reflection, scanning electron microscope, goniometer and porometer to determine the desired hydrophobic membrane for direct contact membrane distillation (DCMD). The addition of FOTS-HNT (fs-HNT) and carnauba wax-HNT (fw-HNT) in the PVDF membrane enhanced the water contact angle (CA) to 127° and 137°, respectively. The presence of fw-HNT in the PVDF membrane exhibited higher liquid entry pressure (LEP) (2.64 bar) compared to fs-HNT in the membrane matrix (1.44 bar). The PVDF/fw-HNT membrane (Pfw-HNT) obtained the highest flux of 7.24 L/m2h with 99.9% salt removal. A stable permeability in the Pfw-HNT membrane was obtained throughout 16 h of DCMD. The incorporation of fw-HNT in the PVDF membrane had improved the anti-wetting properties and the membrane performance with the anti-fouling effect.
    Matched MeSH terms: Waxes
  5. A novel cultivation platform of duckweed (Lemna minor) via application of beeswax superhydrophobic coatings
    Chua MX, Cheah YT, Tan WH, Chan DJC
    Environ Res, 2023 May 01;224:115544.
    PMID: 36822535 DOI: 10.1016/j.envres.2023.115544
    Conventional establishment of laboratory cultures of duckweed Lemna minor are prepared in beakers, Erlenmeyer flasks or Schott bottles. These conventional cultivation methods limit the available surface area for growth which then causes layering of fronds that reduces the efficiency of plants in sunlight capturing. Here, acrylic sheets were spray-coated with a superhydrophobic (SHP) beeswax suspension and these coated acrylic sheets were used as a novel cultivation platform for L. minor. L. minor was grown for 7 days in conventional glass jar which acted as the control and were compared to SHP coated acrylic (SHPA) and SHP coated acrylic with aluminium mesh centrally placed (SHPAM) at similar duration and cultivation conditions. Addition of mesh was to entrap the plantlets and fixed the plantlets' position on the growing platform. The effects of cultivation platforms on growth rate and biochemical compositions of L. minor were monitored. The highest biomass growth was obtained from SHPA cultivation where the relative growth rate (RGR) was 0.0909 ± 0.014 day-1 and the RGR was 2.17 times higher than the control. Moreover, L. minor harvested from SHPA displayed the highest values in total protein content, total carbohydrates content and crude lipid percentage. The values were 156.04 ± 12.13 mg/g, 94.75 ± 9.02 mg/g and 7.09 ± 1.14% respectively. However, the control showed the highest total chlorophyll content which was 0.7733 ± 0.042 mg/g FW. Although SHPA obtained a slightly lower chlorophyll content than the control, this growing platform is still promising as it displayed the highest growth rate as well as other biochemical composition. Hence, this study proved that the proposed method that applied superhydrophobic properties in cultivation of L. minor provided a larger surface area for L. minor to grow, which then resulted in a greater biomass production while simultaneously maintaining the quality of the biochemical compositions of duckweeds.
    Matched MeSH terms: Waxes/metabolism; Waxes/pharmacology
  6. Synergistic interactions between lecithin and fruit wax in oleogel formation
    Okuro PK, Tavernier I, Bin Sintang MD, Skirtach AG, Vicente AA, Dewettinck K, et al.
    Food Funct, 2018 Mar 01;9(3):1755-1767.
    PMID: 29508864 DOI: 10.1039/c7fo01775h
    In this study, the effect of lecithin (LEC) on the crystallization and gelation of fruit wax (FW) with sunflower oil was researched. A synergistic effect on the gel strength was observed at FW : LEC ratios of 75 : 25 and 50 : 50, compared to the corresponding single component formulations (100 : 0 and 0 : 100). Even below the critical gelling concentration (Cg) of FW, the addition of lecithin enabled gel formation. Lecithin affected the thermal behavior of the structure by delaying both crystallization and gel formation. The phospholipid acted as a crystal habit modifier changing the microstructure of the oleogel, as was observed by polarized light microscopy. Cryo-scanning electron microscopy revealed a similar platelet-like arrangement for both FW as a single oleogelator and FW in combination with LEC. However, a denser structure could be observed in the FW : LEC oleogelator mixture. Both the oil-binding capacity and the thixotropic recovery were enhanced upon lecithin addition. These improvements were attributed to the hydrogen bonding between FW and LEC, as suggested by Raman spectroscopy. We hypothesized that lecithin alters the molecular assembly properties of the FW due to the interactions between the polar moieties of the oleogelators, which consequently impacts the hydrophobic tail (re)arrangement in gelator-gelator and solvent-gelator interactions. The lipid crystal engineering approach followed here offered prospects of obtaining harder self-standing structures at a lower oleogelator concentration. These synergistic interactions provide an opportunity to reduce the wax concentration and, as such, the waxy mouthfeel without compromising the oleogel properties.
    Matched MeSH terms: Waxes/chemistry*
  7. Fulltext The Effect of Cavity Design on Fracture Resistance and Failure Pattern in Monolithic Zirconia Partial Coverage Restorations - An In vitro Study
    Harsha MS, Praffulla M, Babu MR, Leneena G, Krishna TS, Divya G
    J Clin Diagn Res, 2017 May;11(5):ZC45-ZC48.
    PMID: 28658906 DOI: 10.7860/JCDR/2017/25305.9856
    INTRODUCTION: Cavity preparations of posterior teeth have been frequently associated with decreased fracture strength of the teeth. Choosing the correct indirect restoration and the cavity design when restoring the posterior teeth i.e., premolars was difficult as it involves aesthetic, biomechanical and anatomical considerations.

    AIM: To evaluate the fracture resistance and failure pattern of three different cavity designs restored with monolithic zirconia.

    MATERIALS AND METHODS: Human maxillary premolars atraumatically extracted for orthodontic reasons were chosen. A total of 40 teeth were selected and divided into four groups (n=10). Group I-Sound teeth (control with no preparation). Group II-MOD Inlay, Group III-Partial Onlay, Group IV-Complete Onlay. Restorations were fabricated with monolithic partially sintered zirconia CAD (SAGEMAX- NexxZr). All the 30 samples were cemented using Multilink Automix (Ivoclar) and subjected to fracture resistance testing using Universal Testing Machine (UTM) (Instron) with a steel ball of 3.5 mm diameter at crosshead speed of 0.5 mm/minute. Stereomicroscope was used to evaluate the modes of failure of the fractured specimen. Fracture resistance was tested using parametric one way ANOVA test, unpaired t-test and Tukey test. Fracture patterns were assessed using non-parametric Chi-square test.

    RESULTS: Group IV (Complete Onlay) presented highest fracture resistance and showed statistical significant difference. Group II (MOD Inlay) and Group III (Partial Onlay) showed significantly lower values than the Group I (Sound teeth). However, Groups I, II and III presented no significant difference from each other. Coming to the modes of failure, Group II (MOD Inlay) and Group III (Partial Onlay) presented mixed type of failures; Group IV (Complete Onlay) demonstrated 70% Type I failures.

    CONCLUSION: Of the three cavity designs evaluated, Complete Onlay had shown a significant increase in the fracture resistance than the Sound teeth.

    Matched MeSH terms: Waxes
  8. Improvement of wheat straw anaerobic digestion through alkali pre-treatment: Carbohydrates bioavailability evaluation and economic feasibility
    Romero-Güiza MS, Wahid R, Hernández V, Møller H, Fernández B
    Sci Total Environ, 2017 Oct 01;595:651-659.
    PMID: 28402918 DOI: 10.1016/j.scitotenv.2017.04.006
    Lignocellulosic biomasses such as wheat straw are widely used as a feedstock for biogas production. However, these biomasses are mainly composed of a compact fibre structure and therefore, it is recommended to treat them prior to its usage for biogas production in order to improve their bioavailability. The aim of this work is to evaluate, in terms of performance stability, methane yield and economic feasibility, two different scenarios: a mesophilic codigestion of wheat straw and animal manure with or without a low-energy demand alkaline pre-treatment (0.08gKOHgTS-1of wheat straw, for 24h and at 25°C). Besides this, said pre-treatment was also analysed based on the improvement of the bioavailable carbohydrate content in the untreated versus the pre-treated wheat straw. The results pointed out that pre-treated wheat straw prompted a more stable performance (in terms of pH and alkalinity) and an improved methane yield (128% increment) of the mesophilic codigestion process, in comparison to the "untreated" scenario. The pre-treatment increased the content of cellulose, hemicellulose and other compounds (waxes, pectin, oil, etc.) in the liquid fraction, from 5% to 60%, from 11.5% to 39.1% TS and from 57% to 79% of the TS in the liquid fraction for the untreated and pre-treated wheat straws, respectively. Finally, the pre-treated scenario gained an energy surplus of a factor 13.5 and achieved a positive net benefit of 90.4€tVS-WS-1d-1, being a favourable case for an eventual scale-up of the combined process.
    Matched MeSH terms: Waxes
  9. Fulltext Optimization of natural lipstick formulation based on pitaya (Hylocereus polyrhizus) seed oil using D-optimal mixture experimental design
    Kamairudin N, Gani SS, Masoumi HR, Hashim P
    Molecules, 2014;19(10):16672-83.
    PMID: 25325152 DOI: 10.3390/molecules191016672
    The D-optimal mixture experimental design was employed to optimize the melting point of natural lipstick based on pitaya (Hylocereus polyrhizus) seed oil. The influence of the main lipstick components-pitaya seed oil (10%-25% w/w), virgin coconut oil (25%-45% w/w), beeswax (5%-25% w/w), candelilla wax (1%-5% w/w) and carnauba wax (1%-5% w/w)-were investigated with respect to the melting point properties of the lipstick formulation. The D-optimal mixture experimental design was applied to optimize the properties of lipstick by focusing on the melting point with respect to the above influencing components. The D-optimal mixture design analysis showed that the variation in the response (melting point) could be depicted as a quadratic function of the main components of the lipstick. The best combination of each significant factor determined by the D-optimal mixture design was established to be pitaya seed oil (25% w/w), virgin coconut oil (37% w/w), beeswax (17% w/w), candelilla wax (2% w/w) and carnauba wax (2% w/w). With respect to these factors, the 46.0 °C melting point property was observed experimentally, similar to the theoretical prediction of 46.5 °C. Carnauba wax is the most influential factor on this response (melting point) with its function being with respect to heat endurance. The quadratic polynomial model sufficiently fit the experimental data.
    Matched MeSH terms: Waxes/chemistry*
  10. Fulltext Influence of exposure time to coffee on color stability of selected composite resin veneers
    Thiyab, Amar M., Mahmood, Nik Zarina N., Hassan, Mohamed Ibrahim A.
    Compendium of Oral Science, 2016;3(1):9-16.
    MyJurnal
    Objectives: The aim of the study is to evaluate the effect of the time and instant coffee solution on the color stability of three types of composite resin based veneer systems. Materials and Methods: 24 composite resin veneer samples were selected and divided into three groups: two groups of prefabricated veneers (Edelweiss, Ultradent Inc™ (EDL) and Componeer, Coltène/ Whaledent AGTM (CMP)) and one group of laboratory made (Nexco, Ivoclar Vivadent (NEX)) veneer system were tested (n=8). Specimens were prepared and stored in staining solution (instant coffee) and assessed color changes with Minolta spectrophotometer every three days for a period of 27 days, after which color differences (ΔE*) were calculated. Data collection and analysis was done using one-way ANOVA and Student’s t-test (α=0.05). Results: One-way ANOVA revealed a significant difference in color stability between the two veneer systems. NEX group veneer system exhibited the highest color stability (ΔE*= 0.73 ± 0.5) as compared to prefabricated veneer groups (EDL 10.07 ± 5.15, CMP 7.41 ± 4.64) with p value
    Matched MeSH terms: Waxes
  11. Fulltext Nanoemulsification of Rice Bran Wax Policosanol Enhances Its Cardio-protective Effects via Modulation of Hepatic Peroxisome Proliferator-activated Receptor gamma in Hyperlipidemic Rats
    Ishaka A, Imam MU, Ismail M
    J Oleo Sci, 2020;69(10):1287-1295.
    PMID: 33028753 DOI: 10.5650/jos.ess20098
    Policosanol, a mixture of long-chain alcohols found in animal and plant waxes, has several biological effects including lipid-lowering that have been extensively studied. However, its bioavailability is low. To investigate the effect of nanoemulsified rice bran wax policosanol (NPOL) on plasma homocysteine, heart and liver histology in hyperlipidemic rats, high-fat diet containing 2.5% cholesterol was used to induce hyperlipidemia in Sprague Dawley rats. The hyperlipidemic rats were treated with NPOL and rice bran wax policosanol (POL) in comparison with normal diet (ND), high-cholesterol diet (HCD) and simvastatin-treated rats. Plasma homocysteine, heart and liver histology, and hepatic mRNA expression of peroxisome proliferator-activated receptor gamma (PPARG) were evaluated. The NPOL group, similar to the simvastatin group, showed reduced plasma homocysteine, preserved heart and liver histology, and down-regulated hepatic PPARG mRNA in comparison to the control group, and was better than the POL group. The results suggest that the modest effect of NPOL on homocysteine and preservation of heart and liver histology could be through the regulation of PPARG expression on a background of increased assimilation of rice bran wax policosanol.
    Matched MeSH terms: Waxes/chemistry*
  12. Fulltext Diabetic hidden gem: high amylose content in Sabah’s traditional rice germplasm [Abstract]
    Tyng CF, Fui LF, Abdul Latip M, Kumar V
    Malaysian Journal of Medicine and Health Sciences, 2019;15(106):17.
    MyJurnal
    ABSTRACTS FOR THE 1ST INTERNATIONAL BORNEO HEALTHCARE AND PUBLIC HEALTH CONFERENCE AND 4TH BORNEO TROPICAL MEDICINE AND INFECTIOUS DISEASE CONGRESS. New Frontiers in Health: Expecting the Unexpected. Held at the Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia. 3rd-5th September 2019
    Introduction: Rice is classified as waxy, very low, low, intermediate and high based on its amylose content (AC). Most people prefer to consume intermediate AC rice because of its texture which tends to appear in between low (moist and sticky) and high (dry and less tender). Although rice with high AC appears dry and less tender, it usually possesses a low glycemic index (GI) i.e. a slower increase in blood glucose level after the consumption of food. Consequently, people with diabetes are recommended to eat low and intermediate GI foods. Although, rice is generally categorised as a high GI staple food there are some exceptions to it. For example, the premium Basmati aromatic rice possesses a low GI and is recommended for diabetic patients. The study aimed to identify Sabah’s traditional rice germplasm with low GI via AC that may be used as a replacement to commercial rice varieties.
    Methods: A total of 110 traditional rice samples were obtained from rice fields located in the Tuaran and Kota Belud districts of Sabah. The AC in each sample was determined via I:KI method (ISO AACC-6647).
    Results: We found that 46 (41.8%), 51 (46.4%), 7 (6.4%) and 6 (5.5%) Sabah’s traditional rice samples possess high, intermediate, low and very low AC, respectively. The intermediate AC type is predominant in Sabah’s traditional rice germplasm as it is the preferred rice texture by the general population. We have identified 46 rice germplasm with high AC type (i.e. with low GI value). The AC content in these is comparable to the Basmati rice and may be suitable candidates for diabetic patients.
    Conclusion: The present study showed Sabah’s traditional rice germplasm has the potential to be promoted as a low GI rice cultivar based on AC for diabetic patients in order to prevent spikes in blood glucose levels while still enjoying the staple food
    Matched MeSH terms: Waxes
  13. Gamma irradiation of corn starches with different amylose-to-amylopectin ratio
    Chung KH, Othman Z, Lee JS
    J Food Sci Technol, 2015 Oct;52(10):6218-29.
    PMID: 26396368 DOI: 10.1007/s13197-014-1700-4
    Corn starches with different amylose-to-amylopectin ratio (waxy, normal, Hylon V, and Hylon VII) were treated with five doses of gamma irradiation (1, 5, 10, 25, and 50 kGy). The effects of gamma irradiation on the physicochemical properties of starch samples were investigated. Waxy samples showed an increase of amylose-like fractions when irradiated at 10 kGy. The reduction in apparent amylose content increased with amylose content when underwent irradiation at 25 and 50 kGy. Low amylose starches lost their pasting ability when irradiated at 25 and 50 kGy. Results from thermal behavior and pasting profile suggested that low level of cross-linking occurred in Hylon VII samples irradiated at 5 kGy. Severe reduction in pasting properties, gelatinization temperatures and relative crystallinity with increasing irradiation intensity revealed that waxy samples were affected more by gamma irradiation; this also indicated amylopectin was the starch fraction most affected by gamma irradiation. Alteration level was portrayed differently when different kind of physicochemical properties were investigated, in which the pasting properties and crystallinity of starches were more immensely influenced by gamma irradiation while thermal behavior was less affected. Despite the irradiation level, the morphology and crystal pattern of starch granules were found remain unchanged by irradiation.
    Matched MeSH terms: Waxes
  14. A practical three visit complete denture system
    Ling BC
    Ann R Australas Coll Dent Surg, 2000 Oct;15:66-8.
    PMID: 11709981
    Standard prosthodontic procedures require five visits to construct a set of complete maxillary and mandibular dentures. Various attempts have been made to reduce these procedures to four or three appointments. However, most of these techniques require the use of visible light polymerized resin as the final denture base materials. Visible light-cured resin materials have inferior physical properties and biocompatibility problems as compared with heat cured polymethylmethacrylate. This paper describes a system of complete denture construction which requires three clinical appointments instead of the usual five visits. This system is made possible by using the VLC base/tray material as the preliminary impression material as well as the application of a new biometric wax occlusion rim. It retains the use of polymethylmethacrylate as the denture base material. This system also utilizes all the procedures used in the conventional five appointment system of complete denture construction.
    Matched MeSH terms: Waxes/chemistry
  15. A three-visit, complete-denture technique utilizing visible light-cured resin for tray and base plate construction
    Ling BC
    Quintessence Int, 2004 Apr;35(4):294-8.
    PMID: 15119715
    This article describes a technique of constructing a set of maxillary and mandibular complete dentures in three visits instead of the usual five clinical appointments. This system of complete-denture construction is made possible because of the combined use of visible light-cured material as an impression tray and record base material, as well as the use of new biometric wax occlusion rims. Unlike some earlier techniques that use light-cured resin composites as the denture base materials, this method retains the use of heat-cured polymethylmethacrylate as the denture base material.
    Matched MeSH terms: Waxes/chemistry
  16. Fulltext Vacuum/compression valving (VCV) using parrafin-wax on a centrifugal microfluidic CD platform
    Al-Faqheri W, Ibrahim F, Thio TH, Moebius J, Joseph K, Arof H, et al.
    PLoS One, 2013;8(3):e58523.
    PMID: 23505528 DOI: 10.1371/journal.pone.0058523
    This paper introduces novel vacuum/compression valves (VCVs) utilizing paraffin wax. A VCV is implemented by sealing the venting channel/hole with wax plugs (for normally-closed valve), or to be sealed by wax (for normally-open valve), and is activated by localized heating on the CD surface. We demonstrate that the VCV provides the advantages of avoiding unnecessary heating of the sample/reagents in the diagnostic process, allowing for vacuum sealing of the CD, and clear separation of the paraffin wax from the sample/reagents in the microfluidic process. As a proof of concept, the microfluidic processes of liquid flow switching and liquid metering is demonstrated with the VCV. Results show that the VCV lowers the required spinning frequency to perform the microfluidic processes with high accuracy and ease of control.
    Matched MeSH terms: Waxes*
  17. Fulltext Characterization of rice bran wax policosanol and its nanoemulsion formulation
    Ishaka A, Umar Imam M, Mahamud R, Zuki AB, Maznah I
    Int J Nanomedicine, 2014;9:2261-9.
    PMID: 24872689 DOI: 10.2147/IJN.S56999
    Policosanol, a mixture of long-chain alcohols found in animal and plant waxes, has several biological effects; however, it has a bioavailability of less than 10%. Therefore, there is a need to improve its bioavailability, and one of the ways of doing this is by nanoemulsion formulation. Different droplet size distributions are usually achieved when emulsions are formed, which solely depends on the preparation method used. Mostly, emulsions are intended for better delivery with maintenance of the characteristics and properties of the leading components. In this study, policosanol was extracted from rice bran wax, its composition was determined by gas chromatography mass spectrophotometry, nanoemulsion was made, and the physical stability characteristics were determined. The results showed that policosanol nanoemulsion has a nanosize particle distribution below 100 nm (92.56-94.52 nm), with optimum charge distribution (-55.8 to -45.12 mV), pH (6.79-6.92) and refractive index (1.50); these were monitored and found to be stable for 8 weeks. The stability of policosanol nanoemulsion confers the potential to withstand long storage times.
    Matched MeSH terms: Waxes/chemistry*
  18. Fulltext Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage
    Silakhori M, Naghavi MS, Metselaar HSC, Mahlia TMI, Fauzi H, Mehrali M
    Materials (Basel), 2013 Apr 29;6(5):1608-1620.
    PMID: 28809232 DOI: 10.3390/ma6051608
    Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.
    Matched MeSH terms: Waxes
  19. Fulltext Utilisation of palm – based and beeswax coating on the postharvest-life of guava (Psidium guajava L.) during ambient and chilled storage
    Ruzaina, I., Norizzah, A.R., Halimahton Zahrah, M.S., Cheow, C.S., Adi, M.S., Noorakmar, A.W., et al.
    International Food Research Journal, 2013;20(1):265-274.
    MyJurnal
    Guava is a climacteric fruit which has high nutritional content. It is a highly perishable fruit, undergoes rapid postharvest ripening in a few days under ambient condition. This paper aims to determine the effect of palm stearin and palm kernel olein blends on maintaining the quality of guava during storage. Two different coating formulations of palm stearin (PS) and palm kernel olein (PKOo) blends (1:1 and 3:2) were analysed for their slip melting point (SMP), cohesiveness, viscosity and density. Beeswax was used as a commercial coating for comparison whiles the uncoated guava was used as control. These coatings were applied onto guavas by hand-wipe technique using a sponge. Guavas were dried in corrugated fibre board boxes and stored in an air-conditioned room maintained at 20°C while a chiller maintained at 10°C was used for chilled temperature. Coating pick up, thickness and surface area were measured while guava properties were analysed for coating effect on weight loss, O2 and CO2 gases, firmness and glossiness during storage at ambient temperature (20°C) for 21 days and chilled temperature (10ºC) for 30 days. Microstructure analysis was conducted within 2 days of coating at ambient temperature (20ºC). The results obtained indicated that 1:1 PSPKOo blends had higher cohesiveness compared to beeswax. Both PSPKOo blends significantly (p
    Matched MeSH terms: Waxes
  20. Fulltext Fluid-solid phase transition of n-alkane mixtures: Coarse-grained molecular dynamics simulations and diffusion-ordered spectroscopy nuclear magnetic resonance
    Shahruddin S, Jiménez-Serratos G, Britovsek GJP, Matar OK, Müller EA
    Sci Rep, 2019 Jan 30;9(1):1002.
    PMID: 30700804 DOI: 10.1038/s41598-018-37799-7
    Wax appearance temperature (WAT), defined as the temperature at which the first solid paraffin crystal appears in a crude oil, is one of the key flow assurance indicators in the oil industry. Although there are several commonly-used experimental techniques to determine WAT, none provides unambiguous molecular-level information to characterize the phase transition between the homogeneous fluid and the underlying solid phase. Molecular Dynamics (MD) simulations employing the statistical associating fluid theory (SAFT) force field are used to interrogate the incipient solidification states of models for long-chain alkanes cooled from a melt to an arrested state. We monitor the phase change of pure long chain n-alkanes: tetracosane (C24H50) and triacontane (C30H62), and an 8-component surrogate n-alkane mixture (C12-C33) built upon the compositional information of a waxy crude. Comparison to Diffusion Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) results allows the assessment of the limitations of the coarse-grained models proposed. We show that upon approach to freezing, the heavier components restrict their motion first while the lighter ones retain their mobility and help fluidize the mixture. We further demonstrate that upon sub-cooling of long n-alkane fluids and mixtures, a discontinuity arises in the slope of the self-diffusion coefficient with decreasing temperature, which can be employed as a marker for the appearance of an arrested state commensurate with conventional WAT measurements.
    Matched MeSH terms: Waxes
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