Displaying publications 181 - 200 of 597 in total

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  1. Effects of silica on the formation of epoxidised natural rubber/polyvinyl chloride membrane
    Nazwa Jon, Ibrahim Abdullah, Rizafizah Othaman
    Sains Malaysiana, 2013;42:469-473.
    The presence of pores plays an important role for many membrane processes especially in ultrafiltration and microfiltration. Epoxidised natural rubber (ENR)/polyvinyl chloride (PVC) membranes filled with two types of silica fillers were prepared via simultaneous solvent exchange and evaporation of solvent technique. Two types of silica, i.e. microsilica (microcrystalline
    silica powder) and nanosilica (generated from tetraethoxysilane (TEOS)) were used. The chemical composition, morphology and mechanical stability of the membranes were studied. Both types of silica showed good interaction with the membrane matrix. The formation of pores depended on the size of silica particles added. Microsilica produced large pores while insitu generated nanosilica produced nanosized pores. The mechanical properties of membrane improved with the addition
    of silica. The tensile strength increased from 10.6 MPa to 17.8 MPa and 14.5 MPa for nanosilica and microsilica filled membrane while the tensile modulus increased from 1.6 MPa to 3.8 MPa and 3.4 MPa, respectively. Thus, both types of silica acted as a filler as well as pore forming agent for the ENR/PVC membrane.
    Matched MeSH terms: Solvents
  2. In vitro regeneration and comparison of phenolic content, antioxidant and antityrosinase activity of in vivo and in vitro grown asparagus officinalis
    Esmaeili AK, Rosna Mat Taha, Mohajer S, Banisalam B
    Sains Malaysiana, 2016;45:373-381.
    Asparagus officinalis as a valuable medicinal plant has a low multiplication rate using the conventional methods. This study was carried out to establish an efficient in vitro propagation protocol and also to compare some biological activities of in vivo and in vitro grown Asparagus. The nodal explants were cultured on MS medium supplemented with different concentrations of 6-benzylaminopurine (BAP) and 1-Naphthaleneacetic acid (NAA) or kinetin (Kn) and Indolebutyric acid (IBA), under light and dark conditions. After 6 weeks of culture, the highest percentage (100%) of callus formation was found in 17 of treatments under dark condition and 3 treatments under light condition. Also between the two groups of hormones, Kn +IBA showed better results in promoting callus formation. The highest average number of shoots (4.25) of size 4 mm or more per explant, formed under dark condition using 1.5 mg/L BAP mixed with 0.05 mg/L NAA. Rooting was best induced in shoots excised from shoot cultures which were proliferated on MS medium supplemented with an optimal concentration of 0.4 mg/L IBA (2 roots per explant). In the second part of the study, the extracts of in vivo and in vitro grown plants as well as callus tissue were tested for their total phenolic and flavonoid content, antioxidant and antityrosinase activities, using two different extraction solvents (methanol and hexane). The methanol extract of in vivo grown plants showed a significantly higher amount of total phenolic and flavonoid content. The antioxidant activity of tested samples followed this order; in vivo plant > callus > in vitro plant.
    Matched MeSH terms: Solvents
  3. Penentuan Isotop Uranium dan Torium dalam Monazit, Xenotim dan Zirkon Menggunakan Spektrometri Alfa
    Amran B. Ab. Majid, Mohd Zahari Abdullah, Zaharuddin Ahmad
    Sains Malaysiana, 1996;25.
    The determination technique for U (238U, 235U, 234U) and Th (232Th, 230Th, 228Th) isotopes using alpha spectrometry was developed. The developed technique involved digestion, dissolution, coprecipitation, solvent extraction and electrodeposition methods. The NBS River Sediment and Rocky Flats Soil Standard Reference Materials were analysed to determine the accuracy of the technique. A good accuracy and high percentage recovery of the carrier (70 - 90%) indicated that the developed technique was suitable for U and Th isotopes determination. The technique was used to determine the U and Th concentration in monazite, xenotime and zircon samples. The results showed that the U and Th total concentrations were in the range of 21.03 to 171.25 Bq/g and 27.48 to 242.87 Bq/g respectively.
    Kaedah penguraian, pemelarutan, pemendakan bersama, ekstraksi pelarut dan pemendapan elektrik telah dikaji dan digunakan untuk mendapatkan suatu teknik yang terbaik dalam penentuan isotop uranium 234U, 235U & 238U) dan torium 228Th, 230Th & 232Th) menggunakan sistem spektrometri alfa. Kepekatan isotop U dan Th dalam bahan rujukan piawai River Sediment dan Rocky Flats Soil (NBS) telah dianalisis untuk menentukan kejituan teknik yang dibangunkan. Kajian ini mendapati kepekatan isotop yang diperolehi adalah menghampiri nilai teraku (sijil) dan peratus perolehan semula pembawa yang besar (70-90%). Ini menunjukkan teknik yang dibangunkan sesuai digunakan untuk penentuan isotop uranium dan torium. Seterusnya teknik yang dibangunkan telah digunakan untuk menentukan kandungan uranium dan torium dalam sampel monazit, xenotim dan zirkon tempatan. Kepekatan jumlah isotop uranium yang diperolehi didapati berada dalam julat 21.03 - 171.25 Bq/g manakala kepekatan jumlah isotop torium pula terletak antara 27.48 - 242.87 Bq/g.
    Matched MeSH terms: Solvents
  4. Tuning the optical band gap of DH6T by Alq3 dopant
    Fahmi Fariq Muhammad, Khaulah Sulaiman
    Sains Malaysiana, 2011;40.
    Dihexyl-sexithiophene (DH6T) was doped with tris (8-hydroxyquinolinate) aluminum (Alq3) to prepare blends of DH6T/ Alq3 by dissolving the mixture in the chloroform/hexane co-solvent. Solid films with different thickness deposited on quartz substrates were obtained from the blends via casting process. Optical absorption spectroscopy has been performed to measure the optical band gap of pure and doped DH6T as well as variations in the band gap with dopant concentration (weight %). This variation in optical band gap with dopant concentration was determined quantitatively with fitted and extrapolated techniques and observed qualitatively from the red shift appeared along the optical absorption spectra. The results showed that within a specific dopant content, the optical energy gap, Eg of DH6T decreases from 2.69 eV to 1.8 eV with increasing dopant concentration to 23.1%.
    Matched MeSH terms: Solvents
  5. Antioxidant properties of three banana cultivars (Musa Acuminata ‘Berangan’, ‘Mas’ and ‘Raja’) extracts
    Tan ES, Aminah Abdullah, Khalid Hamid Musa, Mohammad Yusof Maskat, Maaruf Abd Ghani
    Sains Malaysiana, 2012;41:319-324.
    The effect of solvent type in antioxidant compounds extraction from banana tissues was studied. The solvent system used was pure methanol, ethanol, acetone and their aqueous solution at 50% and 70% concentrations. Comparison among three common cultivars of banana in Malaysia (Berangan, Mas and Raja) had been done and their antioxidant activities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging system, ferric reducing ability in plasma (FRAP)
    assays and total phenolic content (TPC) assays. Acetone 70% had the strongest antioxidant compounds extraction power as compared to other solvent. All banana samples were found to be low in primary antioxidant but powerful secondary antioxidant source of fruit. The ascending order of banana cultivars in term of their antioxidant activities in all antioxidant assays carried out were Berangan < Mas < Raja. FRAP-TPC assays were highly correlated (R2>0.70) than FRAP-DPPH
    and TPC-DPPH assays due to the same mechanism that occurred in the reaction of FRAP and TPC assays.
    Matched MeSH terms: Solvents
  6. Optimization of injection molding and solvent debinding parameters of stainless steel powder (SS316L) based feedstock for metal injection molding
    MUHAMMAD ILMAN HAKIMI CHUA, ABU BAKAR SULONG, MOHD FAZURI ABDULLAH, NORHAMIDI MUHAMAD
    Sains Malaysiana, 2013;42:1743-1750.
    In this study, injection molding parameters, including green strength, surface quality and green part density, were optimized using the L18 Taguchi orthogonal array. The L25 Taguchi method was used to optimize the green density of solvent debinding parameters. The feedstock consisted of stainless steel powder (SS316L), with powder loading fractions of 63, 63.5 and 64 v/o. The binder compositions used in the study were polyethelene glycol (PEG-73 wt. %), polymethyl methacrilate (PMMA-25 wt. %) and stearic acid (2 wt. %). The Taguchi method was used to optimize the injection parameters. The obtained optimum parameters were as follows: mold temperature of 65oC, injection temperature of 145oC, injection pressure of 650 bar, injection flow rate of 20 m3/s, holding time of 5 s and powder loading of 64% v/o. Analysis of variance results showed that mold temperature has the greatest influence in the production of good green part surface quality and that powder loading gave the best green part strength. Immersion time and temperature were used to optimize for solvent debinding parameters. By optimizing the solvent debinding parameters, an immersion temperature of 61oC and immersion time of 5 h produced the highest density which is the optimum value gain in this study.
    Matched MeSH terms: Solvents
  7. Preparation of palm oil methyl esters for alkenyl succinic anhydride production
    Nur Azreena Idris, Loh SK, Choo YM, Boey PL
    Sains Malaysiana, 2010;39.
    The fractions of fatty acid methyl esters (FAME) i.e. crude palm oil methyl esters (CPOME), RBD palm olein methyl esters (RBD Palm Olein ME) and used frying oil methyl esters (UFOME) rich in unsaturated fatty esters were used to prepare alkenyl succinic anhydrides (ASA). The fractions were obtained via fractional distillation that separated the unsaturated fatty esters from the saturated fatty esters. The fractions with the highest content of unsaturated fatty esters were reacted with maleic anhydride (MA) for 8 hours at 240oC with the MA/FAME ratio of 1.5. The reaction was conducted without catalyst and solvent. The crude alkenyl succinic anhydride (ASA) obtained was purified by column chromatography. The purified compound was characterised by FTIR.
    Matched MeSH terms: Solvents
  8. Preparation of Spectroscopy Study on Organistannum (IV) Compound with Dicarboxylic Acids
    Yip FW, Yang Farina, Ibrahim Baba, Abdul Hamid Othman
    Sains Malaysiana, 2004;33.
    Organostannum(IV) complexes derived from dicarboxylic acids have been successfully synthesised from triphenylstannum(IV) hydroxide (Ph3SnOH). The complexes were obtained by refluxing Ph3SnOH and the respective dicarboxylic acids (malonic, succinic, glutaric and adipic acids) using a Dean and Stark apparatus in the appropriate solvent. The free ligands and complexes were characterised by C, Hand Sn elemental analysis and spectroscopic methods such as infrared and nuclear magnetic resonance (1H, 13C NMR). Structure determination of triphenylstannum(IV) succinate, 2, showed that each dicarboxylate anion was bonded monodentatically to two triphenylstannum(IV) moieties. The geometry surrounding each stannum atom is close to a tetrahedron. Spectroscopic data obtained for all complexes were found to be similar and thus it may be concluded that all complexes have the same structure as 2.
    Matched MeSH terms: Solvents
  9. Electrochemical behaviour of Ni and Ni-PVC electrodes for the electroxidation of ethanol
    Mohd Syafiq Hamdan, Norazzizi Nordin, Fathrita Mohd Amir, Mohamed Rozali Othman
    Sains Malaysiana, 2011;40:1421-1427.
    In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50oC for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/cm2. From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde.
    Matched MeSH terms: Solvents
  10. Properties of immobilized Candida Antarctica lipase B on highly macroporous copolymer
    Handayani N, Achmad S, Miletic N, Loos K, Wahyuningrum D
    Sains Malaysiana, 2011;40.
    In spite of their excellent catalytic properties, enzymes should be improved before their implementation both in industrial and laboratorium scales. Immobilization of enzyme is one of the ways to improve their properties. Candida antarctica lipase B (Cal-B) has been reported in numerous publications to be a particularly useful enzyme catalizing in many type of reaction including regio- and enantio- synthesis. For this case, cross-linking of immobilized Cal-B with 1,2,7,8 diepoxy octane is one of methods that proved significantly more stable from denaturation by heat, organic solvents, and proteolysis than lyophilized powder or soluble enzymes. More over, the aim of this procedure is to improve the activity and reusability of lipase. Enzyme kinetics test was carried out by transesterification reaction between 4-nitrophenyl acetate (pNPA) and methanol by varying substrate concentrations, and the result is immobilized enzymes follows the Michaelis-Menten models and their activity is match with previous experiment. Based on the Vmax values, the immobilized enzymes showed higher activity than the free enzyme. Cross-linking of immobilized lipase indicate that cross-linking by lower concentration of cross-linker, FIC (immobilized lipase that was incubated for 24 h) gave the highest activity and cross-linking by higher concentration of cross-linker, PIC (immobilized lipase that was incubated for 2 h) gives the highest activity. However, pore size and saturation level influenced their activity.
    Matched MeSH terms: Solvents
  11. Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry
    Mustarichie R, Salsabila T, Iskandar Y
    J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
    PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19
    Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.

    Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.

    Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.

    Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.

    Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

    Matched MeSH terms: Solvents
  12. Fulltext Improving Performance of Electrospun Nylon 6,6 Nanofiber Membrane for Produced Water Filtration via Solvent Vapor Treatment
    Abd Halim NS, Wirzal MDH, Bilad MR, Md Nordin NAH, Adi Putra Z, Sambudi NS, et al.
    Polymers (Basel), 2019 Dec 17;11(12).
    PMID: 31861059 DOI: 10.3390/polym11122117
    Electrospun nanofiber membrane (NFM) has a high potential to be applied as a filter for produced water treatment due to its highly porous structure and great permeability. However, it faces fouling issues and has low mechanical properties, which reduces the performance and lifespan of the membrane. NFM has a low integrity and the fine mat easily detaches from the sheet. In this study, nylon 6,6 was selected as the polymer since it offers great hydrophilicity. In order to increase mechanical strength and separation performance of NFM, solvent vapor treatment was implemented where the vapor induces the fusion of fibers. The fabricated nylon 6,6 NFMs were treated with different exposure times of formic acid vapor. Results show that solvent vapor treatment helps to induce the fusion of overlapping fibers. The optimum exposure time for solvent vapor is 5 h to offer full retention of dispersed oil (100% of oil rejection), has 62% higher in tensile strength (1950 MPa) compared to untreated nylon 6,6 NFM (738 MPa), and has the final permeability closest to the untreated nylon 6,6 NFM (733 L/m2.h.bar). It also took more time to get fouled (220 min) compared to untreated NFM (160 min).
    Matched MeSH terms: Solvents
  13. Kinetics studies on effects of extraction techniques on bioactive compounds from Vernonia cinerea leaf
    Alara OR, Abdurahman NH
    J Food Sci Technol, 2019 Feb;56(2):580-588.
    PMID: 30906015 DOI: 10.1007/s13197-018-3512-4
    Recently, unconventional methods especially microwave-assisted hydrodistillation extraction (MAHE) is being used as an alternative technique for extracting bioactive compounds from plant materials due to its advantages over conventional methods such as Soxhlet extraction (SE). In this study, bioactive compounds were extracted from Vernonia cinerea leaf using both MAHE and SE methods. In addition, the kinetic study of MAHE and SE methods were carried out using first- and second-order kinetic models. The results obtained showed that MAHE can extract higher yield of bioactive compounds from V. cinerea leaf in a shorter time and reduced used of extracting solvent compared with SE method. Based on the results obtained, second-order kinetic models can actually describe the extraction of bioactive compounds from V. cinerea leaf through MAHE with extraction rate coefficient of 0.1172 L/gmin and extraction capacity of 1.0547 L/g as compared to SE with 0.0157 L/gmin and 1.1626 L/g of extraction rate coefficient and extraction capacity, respectively. The gas chromatography-mass spectrometry analysis of the oil showed the presence of numerous heavy fractions in the oil obtained through MAHE as compared with the SE method. Moreover, the electric consumption and environmental impacts analysis of the oil suggested that MAHE can be a suitable green technique for extracting bioactive compounds from V. cinerea leaf.
    Matched MeSH terms: Solvents
  14. Fulltext Real Time Microwave Biochemical Sensor Based on Circular SIW Approach for Aqueous Dielectric Detection
    Mohd Bahar AA, Zakaria Z, Md Arshad MK, Isa AAM, Dasril Y, Alahnomi RA
    Sci Rep, 2019 04 02;9(1):5467.
    PMID: 30940843 DOI: 10.1038/s41598-019-41702-3
    In this study, a critical evaluation of analyte dielectric properties in a microvolume was undertaken, using a microwave biochemical sensor based on a circular substrate integrated waveguide (CSIW) topology. These dielectric properties were numerically investigated based on the resonant perturbation method, as this method provides the best sensing performance as a real-time biochemical detector. To validate these findings, shifts of the resonant frequency in the presence of aqueous solvents were compared with an ideal permittivity. The sensor prototype required a 2.5 µL volume of the liquid sample each time, which still offered an overall accuracy of better than 99.06%, with an average error measurement of ±0.44%, compared with the commercial and ideal permittivity values. The unloaded Qu factor of the circular substrate-integrated waveguide (CSIW) sensor achieved more than 400 to ensure a precise measurement. At 4.4 GHz, a good agreement was observed between simulated and measured results within a broad frequency range, from 1 to 6 GHz. The proposed sensor, therefore, offers high sensitivity detection, a simple structural design, a fast-sensing response, and cost-effectiveness. The proposed sensor in this study will facilitate real improvements in any material characterization applications such as pharmaceutical, bio-sensing, and food processing applications.
    Matched MeSH terms: Solvents
  15. A clean approach for functionalized carbon nanotubes by deep eutectic solvents and their performance in the adsorption of methyl orange from aqueous solution
    Ibrahim RK, El-Shafie A, Hin LS, Mohd NSB, Aljumaily MM, Ibraim S, et al.
    J Environ Manage, 2019 Apr 01;235:521-534.
    PMID: 30716672 DOI: 10.1016/j.jenvman.2019.01.070
    In this study two deep eutectic solvents (DESs) were prepared using ethylene glycol (EG) and two different ammonium-based salts. The potential of these DESs as novel agents for CNTs functionalization was examined by performing a comprehensive characterization study to identify the changes developing after the functionalization process. The impact of DESs was obvious by increasing the surface area of CNTs to reach 197.8 (m2/g), and by adding new functional groups to CNTs surface without causing any damage to the unique structure of CNTs. Moreover, CNTs functionalized with DESs were applied as new adsorbents for the removal of methyl orange (MO) from water. The adsorption conditions were optimized using RSM-CCD experimental design. The kinetics and the equilibrium adsorption data were analyzed using different kinetic and isotherm models. According to the regression results, adsorption kinetics data were well described by pseudo-second order model, whereas adsorption isotherm data were best represented by Langmuir isotherm model. The highest recorded maximum adsorption capacity (qmax) value was found to be 310.2 mg/g.
    Matched MeSH terms: Solvents
  16. Fulltext A comparative study on foliage and peels of Hylocereus undatus (white dragon fruit) regarding their antioxidant activity and phenolic content
    Som AM, Ahmat N, Abdul Hamid HA, Azizuddin N
    Heliyon, 2019 Feb;5(2):e01244.
    PMID: 30828665 DOI: 10.1016/j.heliyon.2019.e01244
    Hylocereus undatus foliage is believed to contain antioxidants similar to its peel. Numerous studies have been conducted to determine the total phenolic content (TPC) and antioxidant activity on the Hylocereus undatus pulps and peels; however, similar studies on its foliage have yet to be investigated. In this study, Hylocereus undatus foliage and peels were extracted using two different solvents namely; chloroform and methanol through Folin-Ciocalteu method and Diphenyl-1-Ipicrylhydrazyl (DPPH) free radical scavenging assay for TPC and antioxidant activity, respectively. As for TPC, results revealed that the peels gave higher TPC in both methanol (48.15 mg GAE/100g extract) and chloroform (18.89 mg GAE/100g extract) extractions than foliage (30.3 mg GAE/100g extract and 5.92 mg GAE/100g extract, respectively). However, when a comparison was made between foliage and peels in terms of its scavenging effects in DPPH assay, the peels contained more antioxidants (18.71%) than foliage (38.3%) in the chloroform solvent extracts. This study shows that Hylocereus undatus foliage has a similar antioxidant activity as its peels and is potentially a natural antioxidant in food applications.
    Matched MeSH terms: Solvents
  17. One-pot furfural production using choline chloride-dicarboxylic acid based deep eutectic solvents under mild conditions
    Lee CBTL, Wu TY, Ting CH, Tan JK, Siow LF, Cheng CK, et al.
    Bioresour Technol, 2019 Apr;278:486-489.
    PMID: 30711220 DOI: 10.1016/j.biortech.2018.12.034
    The performances of various anhydrous and aqueous choline chloride-dicarboxylic acid based deep eutectic solvents (DESs) were evaluated for furfural production from oil palm fronds without any additional catalyst. The effects of different carbon chain length dicarboxylic acids and water content in each DES on furfural production were investigated. Oil palm fronds, DES and water (0-5 ml) were mixed and reacted in an oil bath (60-300 min). Reacted oil palm fronds had the potential to be reused as cellulose-rich-valuable by-products. At 100 °C, aqueous choline chloride-oxalic acid (16.4 wt% H2O) produced the highest furfural yield of 26.34% and cellulose composition up to 72.79% in the reacted oil palm fronds. Despite operating at suitable reaction duration for dicarboxylic acid with longer carbon chain length, aqueous choline chloride-malonic acid and aqueous choline chloride-succinic acid performed poorly with furfural yield of less than 1%.
    Matched MeSH terms: Solvents
  18. Fulltext Dataset on controlled production of polyhydroxyalkanoate-based microbead using double emulsion solvent evaporation technique
    Govindasamy S, Syafiq IM, Amirul AA, Amin RM, Bhubalan K
    Data Brief, 2019 Apr;23:103675.
    PMID: 30788397 DOI: 10.1016/j.dib.2019.01.023
    A significant source of microplastics is from the usage of microbeads in the market since petrochemical plastic bead is a material used in cosmetic scrubs. A possible way to counteract the problem is by the substitution of synthetic plastic to natural biodegradable polymer. Polyhydroxyalkanoate (PHA) is a general class of thermoplastic microbial polymer and it is the best alternative to some petrochemical plastics due to its biodegradability. Some PHA has earned its way into cosmetic application due to its biocompatibility. This data article reports data on the development of biodegradable microbeads by using the double emulsion solvent evaporation technique. Our data describe the extraction of biopolymer from marine bacteria that was cultivated in shaken flask culture, removal of endotoxins using oxidizing agent, the production of microbeads using a peristaltic pump with a specific flowrate and silicon tubing, and the cytotoxicity of the microbeads.
    Matched MeSH terms: Solvents
  19. Production and characterization of the defatted oil palm shell nanoparticles
    Abdul Khalil HPS, Md. Sohrab Hossain, Nur Amiranajwa AS, Nurul Fazita MR, Mohamad Haafiz MK, Suraya N, et al.
    Sains Malaysiana, 2016;45:833-839.
    This present study was conducted to produce defatted oil palm shell (OPS) nanoparticles. Wherein, the OPS nanoparticles
    were defatted by solvent extraction method. Several analytical methods including transmission electron microscope (TEM),
    X-ray diffraction (XRD), particle size analyzer, scanning electron microscope (SEM), SEM energy dispersive X-ray (SEM-EDX)
    and thermal gravimetric analyzer (TGA) were used to characterize the untreated and defatted OPS nanoparticles. It was
    found that 75.3% OPS particles were converted into nanoparticles during ball milling. The obtained OPS nanoparticles had
    smaller surface area with angular, irregular and crushed shapes under SEM view. The defatted OPS nanoparticles did not
    show any agglomeration during TEM observation. However, the untreated OPS nanoparticles had higher decomposition
    temperature as compared to the defatted OPS nanoparticles. Based on the characterization results of the OPS nanoparticles,
    it is evident that the defatted OPS nanoparticles has the potentiality to be used as filler in biocomposites
    Matched MeSH terms: Solvents
  20. Fluorescence quenching reaction of chlorophyll a by tris(acetylacetonate)iron(iii) in various solvents
    Leesakul N, Masen D, Grampp G
    Sains Malaysiana, 2017;46:1369-1377.
    hlorophyll a is known as the prevailing light absorbing pigment giving a strong absorption and fluorescence emission in visible region. Quenching reactions of the chlorophyll a fluorescence by Fe(acac)3 were precisely investigated in various organic solvents which are benzene toluene, ethanol, methanol, dmf, dmso and acetonitrile. Electron transfer performance of chlorophyll a by Fe(acac)3 was investigated from oxidative quenching reaction. Herein, the simplified Rehm-Weller relationship was used to calculate the free energy change of the photo-induced electron transfer reaction. Emission intensity decreased when the concentration of Fe(acac)3 quencher was increased. Non-linear Stern-Volmer plots are found to be affected by inner filter effect more than the ground state complex formation. Rate of quenching reactions (kq) were determined from the Stern-Volmer equation with corrected inner filter effect. The rates of quenching reactions occurred faster in high viscous solvents.
    Matched MeSH terms: Solvents
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