Displaying publications 1 - 20 of 47 in total

Abstract:
Sort:
  1. Ahmad Saat, Zaini Hamzah
    MyJurnal
    Clay has been regarded as very important natural industrial materials. All these industries exploit the properties that clay can be molded into any shape and fired to dry without losing its form. A study was carried out on clay samples from eight sites in the north-eastern part of Peninsular Malaysia. The study was accomplished by using X-ray diffraction (XRD) technique. The x-ray diffraction spectra obtained enable the determination of the lattice spacing associated with the types of clay and nonclay minerals present in the samples. Results of the study shows that the major components of clay minerals present in all samples studied are kaolinite and illite. The presence of kaolinite is confirmed by firing test in which the kaolinite diffraction peaks disappeared upon heating the samples at 600 o C. The presence of non-clay minerals such as quartz, mica, feldspar and chlorite are also observed.
    Matched MeSH terms: Potassium Compounds
  2. Al-Maqtari AA, Lui JL
    J Prosthodont, 2010 Jul;19(5):347-56.
    PMID: 20456026 DOI: 10.1111/j.1532-849X.2010.00593.x
    The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging.
    Matched MeSH terms: Potassium Compounds/chemistry
  3. Ali LG, Nulit R, Ibrahim MH, Yien CYS
    Sci Rep, 2021 Feb 16;11(1):3864.
    PMID: 33594103 DOI: 10.1038/s41598-021-83434-3
    Rice is an important staple crop produced and consumed worldwide. However, poor seed emergence is one of the main impediments to obtaining higher yield of rice especially in hot and dry ecosystems of the world that are ravaged by drought. Therefore, this study was carried out to evaluate the effects of potassium nitrate (KNO3), salicylic acid (SA) and silicon dioxide (SiO2) priming in improving emergence, seedling growth, biochemical attributes and antioxidant activities of FARO44 rice under drought conditions. Rice seedlings primed with 2.5% and 5% KNO3, 3% and 3.5% SiO2, and 1 mM and 2.5 mM SA were subjected to three drought levels of low, moderate and severe under the greenhouse. Seed emergence, seedling growth, biochemical attributes and antioxidant activities were thereafter evaluated. Seed priming experiments were laid in a completely randomized design with five replicates per treatment. The results found that rice seedlings responded differently to different priming treatments. However, all primed rice seedlings had significantly (P ≤ 0.05) improved emergence percentage (72-92%), seedling growth, seedling vigor, seedling fresh and dry biomass and shorter emergence time compared with controls. Likewise, total soluble protein content, activities of catalase, ascorbate peroxidase and superoxide dismutase, carbohydrate, soluble sugar and total chlorophyll contents of rice seedlings were increased by more than two-folds by seed priming compared with control. Salicylic acid showed less effect in increasing emergence, seedling growth, antioxidant activities and biochemical attributes of rice. Thus, this study established that seed priming with KNO3 (2.5% and 5%) and SiO2 (3% and 3.5%) were more effective in improving emergence, seedling growth, biochemical attributes and antioxidant activities of FARO44. Thus, priming of FARO44 rice with this chemical is recommended for fast emergence, seedling growth and drought resistance in dry ecosystems.
    Matched MeSH terms: Potassium Compounds/pharmacology*
  4. Amid M, Abdul Manap MY, Mustafa S
    PMID: 23770734 DOI: 10.1016/j.jchromb.2013.05.009
    As a novel method of purification, an aqueous organic phase system (AOPS) was employed to purify pectinase from mango waste. The effect of different parameters, such as the alcohol concentration (ethanol, 1-propanol, and 2-propanol), the salt type and concentration (ammonium sulfate, potassium phosphate and sodium citrate), the feed stock crude load, the aqueous phase pH and NaCl concentration, were investigated in the recovery of pectinase from mango peel. The partition coefficient (K), selectivity (S), purification factor (PF) and yield (Y, %) were investigated in this study as important parameters for the evaluation of enzyme recovery. The desirable partition efficiency for pectinase purification was achieved in an AOPS of 19% (w/w) ethanol and 22% (w/w) potassium phosphate in the presence of 5% (w/w) NaCl at pH 7.0. Based on the system, the purification factor of pectinase was enhanced 11.7, with a high yield of 97.1%.
    Matched MeSH terms: Potassium Compounds
  5. Atif M, Khalid SH, Onn Kit GL, Sulaiman SA, Asif M, Chandersekaran A
    J Young Pharm, 2013 Mar;5(1):26-9.
    PMID: 24023449 DOI: 10.1016/j.jyp.2013.01.005
    A simple, sensitive and selective HPLC method with UV detection for determination of Glipizide in human plasma was developed. Liquid-liquid extraction method was used to extract the drug from the plasma samples. Chromatographic separation of Glipizide was achieved using C18 column (ZORBAX ODS 4.6 × 150 mm). The mobile phase was comprised of 0.01 M potassium dihydrogen phosphate and acetonitrile (65:35, v/v) adjusted to pH 4.25 with glacial acetic acid. The analysis was run at a flow rate of 1.5 mL/min with an injection volume was 20 μL. The detector was operated at 275 nm. The calibration curve was linear over a concentration range of 50-1600 ng/mL. Intra-day and inter-day precision and accuracy values were below 15%. The limit of quantification was 50 ng/mL and the mean recovery was above 98%. Freeze-thaw, short-term, long-term and post-preparative stability studies showed that Glipizide in plasma sample was stable. The method may be successfully applied to analyze the Glipizide concentration in plasma samples for bioavailability and bioequivalence studies.
    Matched MeSH terms: Potassium Compounds
  6. Baroutian S, Aroua MK, Raman AA, Sulaiman NM
    Bioresour Technol, 2011 Jan;102(2):1095-102.
    PMID: 20888219 DOI: 10.1016/j.biortech.2010.08.076
    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.
    Matched MeSH terms: Potassium Compounds/chemistry
  7. Chew KW, Chia SR, Krishnamoorthy R, Tao Y, Chu DT, Show PL
    Bioresour Technol, 2019 Sep;288:121519.
    PMID: 31128541 DOI: 10.1016/j.biortech.2019.121519
    Liquid biphasic flotation (LBF), an integrated process of liquid biphasic system (LBS) and adsorptive bubbles flotation, was used for the purification of C-phycocyanin from S. platensis microalgae. Various experimental parameters such as type of phase forming polymer and salt, concentration of phase forming components, system pH, volume ratio, air flotation time and crude extract concentration were evaluated to maximise the C-phycocyanin recovery yield and purity. The optimal conditions for the LBF system achieving C-phycocyanin purification fold of 3.49 compared to 2.43 from the initial LBF conditions was in polyethylene glycol (PEG) 4000 and potassium phosphate combination, with 250 g/L of polymer and salt concentration each, volume ratio of 1:0.85, system pH of 7.0, air flotation duration of 7 min and phycocyanin crude extract concentration of 0.625 %w/w. The LBF has effectively enhanced the purification of C-phycocyanin in a cost effective and simple processing.
    Matched MeSH terms: Potassium Compounds
  8. Dailin DJ, Elsayed EA, Othman NZ, Malek R, Phin HS, Aziz R, et al.
    Saudi J Biol Sci, 2016 Jul;23(4):495-502.
    PMID: 27298582 DOI: 10.1016/j.sjbs.2015.06.003
    Lactobacillus kefiranofaciens is non-pathogenic gram positive bacteria isolated from kefir grains and able to produce extracellular exopolysaccharides named kefiran. This polysaccharide contains approximately equal amounts of glucose and galactose. Kefiran has wide applications in pharmaceutical industries. Therefore, an approach has been extensively studied to increase kefiran production for pharmaceutical application in industrial scale. The present work aims to maximize kefiran production through the optimization of medium composition and production in semi industrial scale bioreactor. The composition of the optimal medium for kefiran production contained sucrose, yeast extract and K2HPO4 at 20.0, 6.0, 0.25 g L(-1), respectively. The optimized medium significantly increased both cell growth and kefiran production by about 170.56% and 58.02%, respectively, in comparison with the unoptimized medium. Furthermore, the kinetics of cell growth and kefiran production in batch culture of L. kefiranofaciens was investigated under un-controlled pH conditions in 16-L scale bioreactor. The maximal cell mass in bioreactor culture reached 2.76 g L(-1) concomitant with kefiran production of 1.91 g L(-1).
    Matched MeSH terms: Potassium Compounds
  9. Dehzangi A, Larki F, Hutagalung SD, Goodarz Naseri M, Majlis BY, Navasery M, et al.
    PLoS One, 2013;8(6):e65409.
    PMID: 23776479 DOI: 10.1371/journal.pone.0065409
    In this letter, we investigate the fabrication of Silicon nanostructure patterned on lightly doped (10(15) cm(-3)) p-type silicon-on-insulator by atomic force microscope nanolithography technique. The local anodic oxidation followed by two wet etching steps, potassium hydroxide etching for silicon removal and hydrofluoric etching for oxide removal, are implemented to reach the structures. The impact of contributing parameters in oxidation such as tip materials, applying voltage on the tip, relative humidity and exposure time are studied. The effect of the etchant concentration (10% to 30% wt) of potassium hydroxide and its mixture with isopropyl alcohol (10%vol. IPA ) at different temperatures on silicon surface are expressed. For different KOH concentrations, the effect of etching with the IPA admixture and the effect of the immersing time in the etching process on the structure are investigated. The etching processes are accurately optimized by 30%wt. KOH +10%vol. IPA in appropriate time, temperature, and humidity.
    Matched MeSH terms: Potassium Compounds/chemistry
  10. Faezah Sabirin
    MyJurnal
    Blood pressure (BP) measurement was first recorded in 1700's by Hales who concluded that it was due to a pressure in the blood (1 , 2]. This is his well renowned discovery besides his other experiments on the capacity of ventricles and many other feature of circulatory system. The development of BP measurement was then rather quiet until about a century later. The accurate study of BP started with the introduction of mercury manometer by Poiseuille in 1800's who demonstrated that the arterial pressure was maintained in smaller arteries and that the blood flow through mesenteric bed did not depend on development of the venous change but varied directly with arterial pressure [3]. In the year of 1928, Poiseuille work was recognised when he won the gold medal of Royal Academy of Medicine for his doctoral dissertation on the measurement of BP using mercury manometer that was directly inserted with cannula filled with potassium bicarbonate as anticoagulant into an artery [3]. Later, his invention has enabled Carl Ludwig to develop kymograph, a method to record clinical physiological data including the BP measurements [3]. (Copied from article).
    Matched MeSH terms: Potassium Compounds
  11. Foo KY, Hameed BH
    Bioresour Technol, 2011 Oct;102(20):9814-7.
    PMID: 21871796 DOI: 10.1016/j.biortech.2011.07.102
    Rice husk (RH), an abundant by-product of rice milling, was used for the preparation of activated carbon (RHAC) via KOH and K(2)CO(3) chemical activation. The activation process was performed at the microwave input power of 600 W for 7 min. RHACs were characterized by low temperature nitrogen adsorption/desorption, scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption behavior was examined using methylene blue as adsorbate. The K(2)CO(3)-activated sample showed higher yield and better pore structures and adsorption capacity development than the KOH-activated sample, with a BET surface area, total pore volume and monolayer adsorption capacity of 1165 m(2)/g, 0.78 cm(3)/g and 441.52 mg/g, respectively. The results revealed the feasibility of microwave heating for preparation of high surface area activated carbons from rice husks via K(2)CO(3) activation.
    Matched MeSH terms: Potassium Compounds/chemistry*
  12. Foo KY, Hameed BH
    Bioresour Technol, 2013 Feb;130:696-702.
    PMID: 23334029 DOI: 10.1016/j.biortech.2012.11.146
    In this work, preparation of granular activated carbon from oil palm biodiesel solid residue, oil palm shell (PSAC) by microwave assisted KOH activation has been attempted. The physical and chemical properties of PSAC were characterized using scanning electron microscopy, volumetric adsorption analyzer and elemental analysis. The adsorption behavior was examined by performing batch adsorption experiments using methylene blue as dye model compound. Equilibrium data were simulated using the Langmuir, Freundlich and Temkin isotherm models. Kinetic modeling was fitted to the pseudo-first-order, pseudo-second-order and Elovich kinetic models, while the adsorption mechanism was determined using the intraparticle diffusion and Boyd equations. The result was satisfactory fitted to the Langmuir isotherm model with a monolayer adsorption capacity of 343.94mg/g at 30°C. The findings support the potential of oil palm shell for preparation of high surface area activated carbon by microwave assisted KOH activation.
    Matched MeSH terms: Potassium Compounds/chemistry*
  13. Hosseini S, Han SJ, Arponwichanop A, Yonezawa T, Kheawhom S
    Sci Rep, 2018 Jul 26;8(1):11273.
    PMID: 30050161 DOI: 10.1038/s41598-018-29630-0
    Zinc-air flow batteries exhibit high energy density and offer several appealing advantages. However, their low efficiency of zinc utilization resulted from passivation and corrosion of the zinc anodes has limited their broad application. In this work, ethanol, which is considered as an environmentally friendly solvent, is examined as an electrolyte additive to potassium hydroxide (KOH) aqueous electrolyte to improve electrochemical performance of the batteries. Besides, the effects of adding different percentages of ethanol (0-50% v/v) to 8 M KOH aqueous electrolyte were investigated and discussed. Cyclic voltammograms revealed that the presence of 5-10% v/v ethanol is attributed to the enhancement of zinc dissolution and the hindrance of zinc anode passivation. Also, potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that adding 5-10% v/v ethanol could effectively suppress the formation of passivating layers on the active surface of the zinc anodes. Though the addition of ethanol increased solution resistance and hence slightly decreased the discharge potential of the batteries, a significant enhancement of discharge capacity and energy density could be sought. Also, galvanostatic discharge results indicated that the battery using 10% v/v ethanol electrolyte exhibited the highest electrochemical performance with 30% increase in discharge capacity and 16% increase in specific energy over that of KOH electrolyte without ethanol.
    Matched MeSH terms: Potassium Compounds
  14. Ilias, N.N., Jamal, P., Sulaiman, S., Jaswir, I., Ansari, A.H., Azmi, A.S., et al.
    MyJurnal
    Bioprotein is one of the useful products obtained from biotechnology invention. It is a promising replacement for the commercial fish feed supplement. In this study, the enrichment of the bioprotein content after solid state fermentation using palm kernel cake and seaweed by the white rot fungus: Phanerochaete chrysoporium and yeast: Candida utilis was carried out. The growth media components were selected from 11 types of media using Plackett-Burman design (hereinafter PBD) and were optimized by one-factor-at-a-time (OFAT) method with bioprotein concentration (mg/g) as the response. From the screening result using PBD, three media components, namely K2HPO4, CuSO4.5H2O and MnSO4.H2O were selected for further optimization using OFAT method because of their positive contributions to the response. The final results showed that 5.0 g/L K2HPO4, 3.0 g/L CuSO4.5H2O and 0.1 g/L MnSO4.H2O were there to be the optimum media constituents with 9.0 g/L, MgSO4.7H2O, 0.1 g/L, CaCl2.H2O, 3.0 g/L FeSO4.7H2O and 3.0 g/L peptone as fixed compositions. At this optimum concentration, the protein increment of 11% was observed as compared to the results determined in the screening using PBD. The study revealed the benefits of using mixed cultures in improving the protein concentrations which can be used as nutritious fish feed.
    Matched MeSH terms: Potassium Compounds
  15. Jamil SNAM, Daik R, Ahmad I
    Materials (Basel), 2014 Sep 01;7(9):6207-6223.
    PMID: 28788187 DOI: 10.3390/ma7096207
    A synthesis of acrylonitrile (AN)/butyl acrylate (BA)/fumaronitrile (FN) and AN/EHA (ethyl hexyl acrylate)/FN terpolymers was carried out by redox polymerization using sodium bisulfite (SBS) and potassium persulphate (KPS) as initiator at 40 °C. The effect of comonomers, BA and EHA and termonomer, FN on the glass transition temperature (Tg) and stabilization temperature was studied using Differential Scanning Calorimetry (DSC). The degradation behavior and char yield were obtained by Thermogravimetric Analysis. The conversions of AN, comonomers (BA and EHA) and FN were 55%-71%, 85%-91% and 76%-79%, respectively. It was found that with the same comonomer feed (10%), the Tg of AN/EHA copolymer was lower at 63 °C compared to AN/BA copolymer (70 °C). AN/EHA/FN terpolymer also exhibited a lower Tg at 63 °C when compared to that of the AN/BA/FN terpolymer (67 °C). By incorporating BA and EHA into a PAN system, the char yield was reduced to ~38.0% compared to that of AN (~47.7%). It was found that FN reduced the initial cyclization temperature of AN/BA/FN and AN/EHA/FN terpolymers to 228 and 221 °C, respectively, in comparison to that of AN/BA and AN/EHA copolymers (~260 °C). In addition, FN reduced the heat liberation per unit time during the stabilization process that consequently reduced the emission of volatile group during this process. As a result, the char yields of AN/BA/FN and AN/EHA/FN terpolymers are higher at ~45.1% and ~43.9%, respectively, as compared to those of AN/BA copolymer (37.1%) and AN/EHA copolymer (38.0%).
    Matched MeSH terms: Potassium Compounds
  16. Johari K, Alias AS, Saman N, Song ST, Mat H
    Waste Manag Res, 2015 Jan;33(1):81-8.
    PMID: 25492720 DOI: 10.1177/0734242X14562660
    The preparation of chars and activated carbon as low-cost elemental mercury adsorbents was carried out through the carbonisation of coconut husk (pith and fibre) and the activation of chars with potassium hydroxide (KOH), respectively. The synthesised adsorbents were characterised by using scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption/desorption analysis. The elemental mercury removal performance was measured using a conventional flow type packed-bed adsorber. The physical and chemical properties of the adsorbents changed as a result of the carbonisation and activation process, hence affecting on the extent of elemental mercury adsorption. The highest elemental mercury (Hg°) adsorption capacity was obtained for the CP-CHAR (3142.57 µg g(-1)), which significantly outperformed the pristine and activated carbon adsorbents, as well as higher than some adsorbents reported in the literature.
    Matched MeSH terms: Potassium Compounds/chemistry*
  17. Khezri R, Hosseini S, Lahiri A, Motlagh SR, Nguyen MT, Yonezawa T, et al.
    Int J Mol Sci, 2020 Oct 02;21(19).
    PMID: 33023274 DOI: 10.3390/ijms21197303
    Zinc-air batteries (ZABs) offer high specific energy and low-cost production. However, rechargeable ZABs suffer from a limited cycle life. This paper reports that potassium persulfate (KPS) additive in an alkaline electrolyte can effectively enhance the performance and electrochemical characteristics of rechargeable zinc-air flow batteries (ZAFBs). Introducing redox additives into electrolytes is an effective approach to promote battery performance. With the addition of 450 ppm KPS, remarkable improvement in anodic currents corresponding to zinc (Zn) dissolution and limited passivation of the Zn surface is observed, thus indicating its strong effect on the redox reaction of Zn. Besides, the addition of 450 ppm KPS reduces the corrosion rate of Zn, enhances surface reactions and decreases the solution resistance. However, excess KPS (900 and 1350 ppm) has a negative effect on rechargeable ZAFBs, which leads to a shorter cycle life and poor cyclability. The rechargeable ZAFB, using 450 ppm KPS, exhibits a highly stable charge/discharge voltage for 800 cycles. Overall, KPS demonstrates great promise for the enhancement of the charge/discharge performance of rechargeable ZABs.
    Matched MeSH terms: Potassium Compounds/pharmacology; Potassium Compounds/chemistry*
  18. Kupaei RH, Alengaram UJ, Jumaat MZ
    ScientificWorldJournal, 2014;2014:898536.
    PMID: 25531006 DOI: 10.1155/2014/898536
    This paper presents the experimental results of an on-going research project on geopolymer lightweight concrete using two locally available waste materials--low calcium fly ash (FA) and oil palm shell (OPS)--as the binder and lightweight coarse aggregate, respectively. OPS was pretreated with three different alkaline solutions of sodium hydroxide (NaOH), potassium hydroxide, and sodium silicate as well as polyvinyl alcohol (PVA) for 30 days; afterwards, oil palm shell geopolymer lightweight concrete (OPSGPC) was cast by using both pretreated and untreated OPSs. The effect of these solutions on the water absorption of OPS, and the development of compressive strength in different curing conditions of OPSGPC produced by pretreated OPS were investigated; subsequently the influence of NaOH concentration, alkaline solution to FA ratio (A/FA), and different curing regimes on the compressive strength and density of OPSGPC produced by untreated OPS was inspected. The 24-hour water absorption value for OPS pretreated with 20% and 50% PVA solution was about 4% compared to 23% for untreated OPS. OPSGPC produced from OPS treated with 50% PVA solution produced the highest compressive strength of about 30 MPa in ambient cured condition. The pretreatment with alkaline solution did not have a significant positive effect on the water absorption of OPS aggregate and the compressive strength of OPSGPC. The result revealed that a maximum compressive strength of 32 MPa could be obtained at a temperature of 65°C and curing period of 4 days. This investigation also found that an A/FA ratio of 0.45 has the optimum amount of alkaline liquid and it resulted in the highest level of compressive strength.
    Matched MeSH terms: Potassium Compounds/chemistry
  19. Leong HY, Su CA, Lee BS, Lan JC, Law CL, Chang JS, et al.
    Bioresour Technol, 2019 Jan;271:30-36.
    PMID: 30261334 DOI: 10.1016/j.biortech.2018.09.093
    Microalgae biorefinery is presently receiving a lot of attention as driven by its production of high value-added products. In this study, an oleaginous microalga Aurantiochytrium limacinum SR21 was cultured for docosahexaenoic acid (DHA) production using 20% (w/v) of K2HPO4-waste feedstock to replace 0.005% (w/v) of KH2PO4 in the flask culture. DHA is an essential nutrient for human's brain functionalities. Collectively, the K2HPO4-waste feedstock with working concentration of 0.005% (w/v) in the cultivation prompted a higher lipid content (8.29%) and DHA production (128.81 mg.L-1). Moreover, natural plant pigment products containing stabilised betacyanins were utilised as natural red colourants for hard candy production. This study develops microalgal cultivation using salt-rich waste feedstock for a higher lipid and DHA content as well as application of natural colouring agents in food products.
    Matched MeSH terms: Potassium Compounds
  20. Lin YK, Show PL, Yap YJ, Ariff AB, Mohammad Annuar MS, Lai OM, et al.
    J Biosci Bioeng, 2016 Jun;121(6):692-696.
    PMID: 26702953 DOI: 10.1016/j.jbiosc.2015.11.001
    Aqueous two-phase system (ATPS) extractive bioconversion provides a technique which integrates bioconversion and purification into a single step process. Extractive bioconversion of gamma-cyclodextrin (γ-CD) from soluble starch with cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) enzyme derived from Bacillus cereus was evaluated using polyethylene glycol (PEG)/potassium phosphate based on ATPS. The optimum condition was attained in the ATPS constituted of 30.0% (w/w) PEG 3000 g/mol and 7.0% (w/w) potassium phosphate. A γ-CD concentration of 1.60 mg/mL with a 19% concentration ratio was recovered after 1 h bioconversion process. The γ-CD was mainly partitioned to the top phase (YT=81.88%), with CGTase partitioning in the salt-rich bottom phase (KCGTase=0.51). Repetitive batch processes of extractive bioconversion were successfully recycled three times, indicating that this is an environmental friendly and a cost saving technique for γ-CD production and purification.
    Matched MeSH terms: Potassium Compounds/chemistry*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links