Displaying publications 81 - 100 of 190 in total

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  1. Fulltext Impact of pre-dilution and flushing on continuous renal replacement therapy
    Koh KH
    Singapore Med J, 2006 Sep;47(9):785-95.
    PMID: 16924361
    Infusing the replacement solution before the filter (pre-dilution) and regular flushing have not been accounted for in conventional mathematical equations. Their effects on various continuous renal replacement therapy (CRRT) parameters, such as ultrafiltration fraction and urea clearance, have not been well studied. We incorporated these parameters into mathematical equations to help in understanding and prescribing CRRT.
    Matched MeSH terms: Urea/blood
  2. The fetal sex ratio and metabolic, biochemical, haematological and clinical indicators of severity of hyperemesis gravidarum
    Tan PC, Jacob R, Quek KF, Omar SZ
    BJOG, 2006 Jun;113(6):733-7.
    PMID: 16709219
    The association between female fetal sex and hyperemesis gravidarum is well established in European and North American populations. The association between female fetuses and severity of hyperemesis remains uncertain. A retrospective study based on case notes review of 166 Asian women hospitalised for hyperemesis was performed. Female fetuses were significantly associated with hyperemesis in our population (P= 0.004, OR 1.6, 95% CI 1.2-2.2) as well as associated with severe ketonuria and high urea. When both severe ketonuria and high urea were present at initial hospital admission for hyperemesis, 83% (95% CI 66-93) of the fetuses were female.
    Matched MeSH terms: Urea/blood
  3. Targeting chemical and thermal stability of ovalbumin by simulated honey sugar cocktail
    Wong YH, Kadir HA, Tayyab S
    Int J Biol Macromol, 2015 Feb;73:207-14.
    PMID: 25434804 DOI: 10.1016/j.ijbiomac.2014.11.015
    Effect of simulated honey sugar cocktail (SHSC) on chemical and thermal stability of ovalbumin (OVA) was investigated using multiple-spectroscopic techniques. Urea-induced denaturation of OVA produced a transition, characterized by the start-, the mid- and the end-points at 3.2 M, 5.9/5.6 M and 8.5/8.0 M urea, respectively, when studied by MRE222nm and tryptophan fluorescence measurements. Presence of 10% or 20% (w/v) SHSC in the incubation mixture shifted the transition curve towards higher urea concentration in a concentration dependent manner. A comparison of far- and near-UV CD, UV-difference, ANS fluorescence and 3-D fluorescence spectral results of native OVA and 5.9 M urea-denatured OVA (U-OVA), obtained in the absence and the presence of 20% (w/v) SHSC suggested SHSC-induced stabilization of U-OVA. Furthermore, a significant shift towards higher denaturant concentration was also noticed in the GdnHCl and thermal transition curves of OVA in the presence of 20% (w/v) SHSC. Taken together, all these results suggested stabilization of OVA against chemical and thermal denaturations by SHSC.
    Matched MeSH terms: Urea/pharmacology
  4. Stabilization of Human Serum Albumin against Urea Denaturation by Diazepam and Ketoprofen
    Manoharan P, Wong YH, Tayyab S
    Protein Pept Lett, 2015;22(7):611-7.
    PMID: 25961707
    Stabilizing effect of diazepam and ketoprofen, Sudlow's site II markers on human serum albumin (HSA) against urea denaturation was studied using fluorescence spectroscopy. The two-step, three-state urea transition of HSA was transformed into a single-step, two-state transition with the abolishment of the intermediate state along with a shift of the transition curve towards higher urea concentrations in the presence of diazepam or ketoprofen. Interestingly, a greater shift in the transition curve of HSA was observed in the presence of ketoprofen compared to diazepam. A comparison of the intrinsic fluorescence and three-dimensional fluorescence spectra of HSA and partially-denatured HSAs, obtained in the absence and the presence of diazepam or ketoprofen suggested significant retention of native-like conformation in the partially-denatured states of HSA in the presence of Sudlow's site II markers. Taken together, all these results suggested stabilization of HSA in the presence of diazepam or ketoprofen, being greater in the presence of ketoprofen.
    Matched MeSH terms: Urea/pharmacology*
  5. Fulltext Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes
    Omar L, Ahmed OH, Ab Majid NM
    ScientificWorldJournal, 2015;2015:574201.
    PMID: 25793220 DOI: 10.1155/2015/574201
    Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-) losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 (+) and NO3 (-) release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 (-) leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 (+) retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 (+) and NO3 (-) release from urea.
    Matched MeSH terms: Urea/chemistry*
  6. Effect of acid hydrolysis on regenerated kenaf core membrane produced using aqueous alkaline-urea systems
    Padzil FN, Zakaria S, Chia CH, Jaafar SN, Kaco H, Gan S, et al.
    Carbohydr Polym, 2015 Jun 25;124:164-71.
    PMID: 25839807 DOI: 10.1016/j.carbpol.2015.02.013
    Bleached kenaf core pulps (BKC) were hydrolyzed in H2SO4 (0.5M) at different time (0min to 90min) at room temperature. After the hydrolysis process, the viscosity average molecular weight (Mŋ) for BKC sample has reduced from 14.5×10(4) to 2.55×10(4). The hydrolyzed BKC was then dissolved in NaOH:urea:water and in LiOH:urea:water mixed solvent at the ratio of 7:12:81 and 4.6:15:80.4, respectively. The increased in hydrolysis time has decreased Mŋ of cellulose leading to easy dissolution process. Higher porosity and transparency with lower crystallinity index (CrI) of regenerated membrane produced can be achieved as the Mŋ reduced. The properties of membrane were observed through FESEM, UV-vis spectrophotometer and XRD. This study has proven that acid hydrolysis has reduced the Mŋ of cellulose, thus, enhanced the properties of regenerated membrane produced with assisted by alkaline/urea system.
    Matched MeSH terms: Urea/chemistry*
  7. Fulltext Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate
    Saeedfar K, Heng LY, Ling TL, Rezayi M
    Sensors (Basel), 2013;13(12):16851-66.
    PMID: 24322561 DOI: 10.3390/s131216851
    A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.
    Matched MeSH terms: Urea/chemistry; Urease/chemistry*
  8. Conformational analysis of champedak galactose-binding lectin under different urea concentrations
    Kameel NI, Wong YH, Shuib AS, Tayyab S
    Plant Physiol Biochem, 2016 Jan;98:57-63.
    PMID: 26642433 DOI: 10.1016/j.plaphy.2015.11.007
    Conformational analysis of champedak galactose-binding (CGB) lectin under different urea concentrations was studied in phosphate-buffered saline (pH 7.2) using far-ultraviolet circular dichroism (far-UV CD), tryptophan (Trp) fluorescence and ANS fluorescence. In all cases, CGB lectin displayed a two-step, three-state transition. The first transition (from the native state to the intermediate state) started at ∼2.0 M urea and ended at ∼4.5 M urea, while the second transition (from the intermediate state to the completely denatured state) was characterized by the start- and end-points at ∼5.75 M and ∼7.5 M urea, respectively, when analyzed by the emission maximum of Trp fluorescence. A marked increase in the Trp fluorescence, ANS fluorescence and -CD values at 218 nm (-CD218 nm) represented the first transition, whereas a decrease in these parameters defined the second transition. On the other hand, emission maximum of the Trp fluorescence showed a continuous increase throughout the urea concentration range. Transformation of tetramer into monomer represented the first transition, whereas the second transition reflected the unfolding of monomer. Far-UV CD, Trp fluorescence and ANS fluorescence spectra were used to characterize the native, the intermediate and the completely denatured states of CGB lectin, obtained at 0.0 M, 5.0 M and 9.0 M urea, respectively. The intermediate state was characterized by the presence of higher secondary structures, increased ANS binding as well as increased Trp fluorescence intensity. A gradual decrease in the hemagglutination activity of CGB lectin was observed with increasing urea concentrations, showing complete loss at 4.0 M urea.
    Matched MeSH terms: Urea/pharmacology*
  9. Fulltext Effects of Nephrolithiasis on Serum DNase (Deoxyribonuclease I and II) Activity and E3 SUMO-Protein Ligase NSE2 (NSMCE2) in Malaysian Individuals
    Yusof F, Mehde AA, Mehdi WA, Raus RA, Ghazali H, Rahman AA
    Biomed Environ Sci, 2015 Sep;28(9):660-5.
    PMID: 26464253 DOI: 10.3967/bes2015.092
    OBJECTIVE: Nephrolithiasis is one of the most common disorders of the urinary tract. The aim of this study was to examine a possible relationship between DNase I/II activity and E3 SUMO-protein ligase NSE2 in the sera of nephrolithiasis patients to evaluate the possibility of a new biomarker for evaluating kidney damage.
    METHODS: Sixty nephrolithiasis patients and 50 control patients were enrolled in a case-control study. Their blood urea, creatinine, protein levels and DNase I/II activity levels were measured by spectrometry. Serum NSMCE2 levels were measured by ELISA. Blood was collected from patients of the government health clinics in Kuantan-Pahang and fulfilled the inclusion criteria.
    RESULTS: The result indicated that mean levels of sera NSMCE2 have a significantly increase (P<0.01) in patients compared to control group. Compared with control subjects, activities and specific activities of serum DNase I and II were significantly elevated in nephrolithiasis patients (P$lt;0.01).
    CONCLUSION: This study suggests that an increase in serum concentrations of DNase I/II and E3 SUMO-protein ligase NSE2 level can be used as indicators for the diagnosis of kidney injury in patients with nephrolithiasis.
    Matched MeSH terms: Urea/blood
  10. Fulltext New triple therapy for the diagnosis of CKD-MBD: a cross-sectional study in Shanxi province
    Zhao Z, Gao Y, Sui W, Zhang Z, Feng L, Wang Z, et al.
    BMJ Open, 2024 Aug 17;14(8):e081485.
    PMID: 39153776 DOI: 10.1136/bmjopen-2023-081485
    OBJECTIVES: To seek a triple combination of biomarkers for early diagnosis of chronic kidney disease-mineral and bone metabolic disorder and to explore the diagnostic efficacy of β2-microglobulin, parathyroid hormone and blood urea nitrogen in chronic kidney disease-mineral and bone metabolic disorder.

    PARTICIPANTS: We collected medical records of 864 patients with chronic kidney disease (without direct contact with patients) and divided them into two groups based on the renal bone disease manifestations of all patients.

    PRIMARY AND SECONDARY OUTCOME MEASURES: There were 148 and 716 subjects in the Chronic kidney disease-mineral and bone metabolic disorder and the control groups, respectively. The aggregated data included basic information and various clinical laboratory indicators, such as blood lipid profile, antibody and electrolyte levels, along with renal function-related indicators.

    RESULTS: It was observed that most renal osteopathy occurs in the later stages of chronic kidney disease. In the comparison of two clinical laboratory indicators, 16 factors were selected for curve analysis and compared. We discovered that factors with high diagnostic values were β2-microglobulin, parathyroid hormone and blood urea nitrogen.

    CONCLUSIONS: The triple combination of β2-microglobulin+parathyroid hormone+blood urea nitrogen indicators can play the crucial role of a sensitive indicator for the early diagnosis of chronic kidney disease-mineral and bone metabolic disorder and in preventing or delaying the progress of chronic kidney disease-mineral and bone metabolic disorder.

    Matched MeSH terms: Blood Urea Nitrogen*
  11. Fulltext Kinetic modeling of bacteriocin-like inhibitory substance secretion by Pediococcus acidilactici Kp10 and its stability in food manufacturing conditions
    Abbasiliasi S, Tan JS, Ibrahim TAT, Ramanan RN, Kadkhodaei S, Mustafa S, et al.
    J Food Sci Technol, 2018 Apr;55(4):1270-1284.
    PMID: 29606741 DOI: 10.1007/s13197-018-3037-x
    This paper deliberates the modelling and validation of bacteriocin-like inhibitory substance (BLIS) secretion by Pediococcus acidilactici Kp10 at different agitation speeds in a stirred tank bioreactor. A range of models namely the re-parameterised logistic, Luedeking-Piret and maintenance energy were assessed to predict the culture performance of the said bacterium. Growth of P. acidilactici Kp10 was enhanced with increased agitation speed up to 600 rpm while BLIS secretion was maximum at 400 rpm but decreased at higher agitation speed. Growth of P. acidilactici aptly subscribed to the re-parameterised logistic model while BLIS secretion and lactose consumption fitted well with the Luedeking-Piret model. The models revealed a relationship between growth of the bacterium and BLIS secretion. Bacterial growth and BLIS secretion were largely affected by the agitation speed of the stirred tank bioreactor which regulated the oxygen transfer to the culture. BLIS secretion by P. acidilactici Kp10 was however enhanced in oxygen-limited culture. The study also assessed BLIS from the perspective of its stability when subjected to factors such as temperature, pH and detergents. Results showed that BLIS produced by this strain was not affected by heat (at 25-100 °C for 20 min and at 121 °C for 15 min), surfactant (Tween 40, 60 and 80 and urea), detergents (up to 1% SDS), organic solvents (50% each of acetone, methanol and ethanol) and stable in a wide range of pH (2-10). The above information are pertinent with reference to commercial applications of this bacterial product in food manufacturing which invariably involve various sterilization processes and subjected to a wide pH range.
    Matched MeSH terms: Urea
  12. Fulltext Inclusion of 2-Mercaptoethanol in Lysis Buffer Could Interfere with Isolation of High Molecular Weight DNA from Freshwater Microalgae
    Yee W, Kumar JN, Muthusamy PD
    Indian J Microbiol, 2018 Mar;58(1):109-113.
    PMID: 29434405 DOI: 10.1007/s12088-017-0698-5
    2-mercaptoethanol (2-ME), alongside polyvinylpyrrolidone is commonly used in plant DNA extractions to deal with polyphenols, which could interfere with extraction and downstream applications. 2-ME is also commonly used to denature proteins and nucleases, especially RNAses. On the contrary, we found that the presence of 2-ME in lysis buffer interfered with DNA extraction from 12 strains of freshwater microalgae, resulting in DNA with poor integrity. We also found that the TNES-urea buffer, commonly used for preservation and DNA extraction from fish, appears as effective as the SDS and CTAB buffer for some microalgae strains. Results from our study suggests that the inclusion of 2-ME in DNA extraction protocols may be detrimental for isolation of good quality DNA from freshwater microalgae, and therefore recommend eliminating it or testing varying concentrations of 2-ME when developing species-specific extraction protocols for microalgae.
    Matched MeSH terms: Urea
  13. Fulltext Protein improvement of banana peel through sequential solid state fermentation using mixed-culture of Phanerochaete chrysosporium and Candida utilis
    Olorunnisola KS, Jamal P, Alam MZ
    3 Biotech, 2018 Oct;8(10):416.
    PMID: 30237963 DOI: 10.1007/s13205-018-1435-4
    Banana peel (BP) is a major waste produced by fruit processing industries. Pre-treatment of BP at different temperatures led to 40% reduction in saponin at 100 °C (from 9.5 to 5.7 mg/g). Sequential mixed culture of Phanerochaete chrysosporium (P. chrysosporium) and Candida utilis (C. utilis) gave highest protein enrichment (88.93 mg/g). There is 26% increase in protein synthesis (from 88.93 to 111.78 mg/g) after media screening. Inclusion of KH2PO4, FeSO4·7H2O, wheat flour and sucrose in the media contributed positively to protein synthesis, while elevated concentration of urea, peptone, K2HPO4, KCl, NH4H2PO4, and MgSO4.7H2O are required to reach optimum protein synthesis. Total soluble sugar (TSS), total reducing sugar (TRS) and total carbohydrate (CHO) consumption varied with respect to protein synthesis in all experimental runs. Optimum protein synthesis required 6 days and inclusion of 5% sucrose, 0.6% NH4H2PO4, 0.4% KCl, and 0.5% MgSO4·7H2O as concentration media constituents to reach 140.95 mg/g protein synthesis equivalent to 300% increase over the raw banana peel protein content (35.0 mg/g).
    Matched MeSH terms: Urea
  14. Fulltext Enhancement of bioplastic polyhydroxybutyrate P(3HB) production from glucose by newly engineered strain Cupriavidus necator NSDG-GG using response surface methodology
    Biglari N, Ganjali Dashti M, Abdeshahian P, Orita I, Fukui T, Sudesh K
    3 Biotech, 2018 Aug;8(8):330.
    PMID: 30073115 DOI: 10.1007/s13205-018-1351-7
    This study aimed to enhance production of polyhydroxybutyrate P(3HB) by a newly engineered strain of Cupriavidus necator NSDG-GG by applying response surface methodology (RSM). From initial experiment of one-factor-at-a-time (OFAT), glucose and urea were found to be the most significant substrates as carbon and nitrogen sources, respectively, for the production of P(3HB). OFAT experiment results showed that the maximum biomass, P(3HB) content, and P(3HB) concentration of 8.95 g/L, 76 wt%, and 6.80 g/L were achieved at 25 g/L glucose and 0.54 g/L urea with an agitation rate of 200 rpm at 30 °C after 48 h. In this study, RSM was applied to optimize the three key variables (glucose concentration, urea concentration, and agitation speed) at a time to obtain optimal conditions in a multivariable system. Fermentation experiments were conducted in shaking flask by cultivation of C. necator NSDG-GG using various glucose concentrations (10-50 g/L), urea concentrations (0.27-0.73 g/L), and agitation speeds (150-250 rpm). The interaction between the variables studied was analyzed by ANOVA analysis. The RSM results indicated that the optimum cultivation conditions were 37.70 g/L glucose, 0.73 g/L urea, and 200 rpm agitation speed. The validation experiments under optimum conditions produced the highest biomass of 12.84 g/L, P(3HB) content of 92.16 wt%, and P(3HB) concentration of 11.83 g/L. RSM was found to be an efficient method in enhancing the production of biomass, P(3HB) content, and P(3HB) concentration by 43, 21, and 74%, respectively.
    Matched MeSH terms: Urea
  15. Assessing ureolytic bacteria with calcifying abilities isolated from limestone caves for biocalcification
    Omoregie AI, Ong DEL, Nissom PM
    Lett Appl Microbiol, 2019 Feb;68(2):173-181.
    PMID: 30537001 DOI: 10.1111/lam.13103
    Biocalcification through the use of ureolytic bacteria and biochemical activities has evolved in recent decades into a fervent resourceful effective technology suitable for soil stabilization, crack repair and bioremediation. Extensive studies have been carried out on numerous ureolytic bacterial species isolated from soils and sewage samples. However, very limited attention has been given to limestone caves with natural calcite formations as a possible source for isolation of ureolytic bacteria. In this study, bacterial isolates were recovered from limestone cave samples to determine their suitability for biocalcification. Twenty-seven morphologically distinct bacterial isolates were identified by partial 16S rRNA gene sequencing and their various genetic diversity was characterized according to their phylogenetic affiliations. Based on the molecular identification, Sporosarcina was the most abundant genus among all the ureolytic isolates, while the rest belonged to Pseudogracilibacillus and Bacillus genera. Analytical analysis on urease measurement showed that urease activities for the isolates ranged from 1·130 to 21·513 mol urea hydrolysed per minute, with isolate NB33 achieving the highest value and TSB4 achieving the lowest value. The estimated CaCO3 precipitates for the isolates ranged from 4·04 to 17·26 mg ml-1 , with isolate NB30 achieving the highest value and TSB20 achieving the lowest value. The findings in this study demonstrated that the ureolytic bacteria from limestone caves are promising bio-calcifying agents. SIGNIFICANCE AND IMPACT OF THE STUDY: Ureolytic bacteria continues to play an important role as microbial tools used in geotechnical engineering for soil biocalcification. Microbial strains with the ability to produce urease enzyme and induce calcium carbonate mineral are often isolated from soil, water and sludge samples. However, screening for these essential microbes from extreme regions such as caves are rarely investigated. In this study, native bacteria which were isolated from limestone cave samples are identified and characterized. The findings suggested that these ureolytic bacterial isolates have the potential to serve as suitable alternative microbial agents for soil strengthening and stabilization.
    Matched MeSH terms: Urea; Urease
  16. Fulltext Effects of Quercetin on Tubular Cell Apoptosis and Kidney Damage in Rats Induced by Titanium Dioxide Nanoparticles
    Alidadi H, Khorsandi L, Shirani M
    Malays J Med Sci, 2018 Mar;25(2):72-81.
    PMID: 30918457 DOI: 10.21315/mjms2018.25.2.8
    Background: Recent studies have demonstrated that many nanoparticles have an adverse or toxic effect on the kidney.

    Objective: To investigate the nephroprotective effect of quercetin (QT) against renal injury induced by titanium dioxide nanoparticles (NTiO2) in rats.

    Methods: NTiO2-intoxicated rats received 50 mg/kg of NTiO2 for seven days. The QT + NTiO2 group was pretreated with QT for seven days before being administered NTiO2. Uric acid, creatinine, and blood urea nitrogen were considered to be biomarkers of nephrotoxicity. Catalase (CAT) and superoxide dismutase (SOD) activities and renal levels of malondialdehyde (MDA) were measured to assess the oxidative stress caused by NTiO2.

    Results: NTiO2 significantly increased the plasma level of the biomarkers. It also significantly decreased the activities of CAT (P = 0.008) and SOD (P = 0.004), and significantly increased the MDA levels (P = 0.007). NTiO2 caused proximal tubule damage, the accumulation of red blood cells, the infiltration of inflammatory cells, and reduced the glomerular diameters, as well as induced apoptosis in the proximal tubules. Pre-treatment with QT attenuated the histological changes, normalised the plasma biomarkers, suppressed oxidative stress, ameliorated the activities of CAT (P = 0.007) and SOD (P = 0.006), and reduced apoptosis (P < 0.001).

    Conclusion: QT was found to have a potent protective effect against nephrotoxicity induced by NTiO2 in rats. It also reduced apoptosis caused by NTiO2.

    Matched MeSH terms: Blood Urea Nitrogen
  17. Comparison of deep eutectic solvents (DES) on pretreatment of oil palm empty fruit bunch (OPEFB): Cellulose digestibility, structural and morphology changes
    Thi S, Lee KM
    Bioresour Technol, 2019 Jun;282:525-529.
    PMID: 30898410 DOI: 10.1016/j.biortech.2019.03.065
    In this work, a novel solvent, deep eutectic solvent (DES) was applied to examine its effectiveness in pretreating OPEFB. Three types of DESs, i.e. choline chloride-lactic acid (ChCl-LA), choline chloride-urea (ChCl-U) and choline chloride-glycerol (ChCl-G) were investigated. The pretreatment performance was based on cellulose digestibility, structural and morphology changes. At molar ratio of 1:2, ChCl-LA attained the highest reducing sugars yield of 20.7%, followed by ChCl-G (20.0%) and ChCl-U (16.9%). FT-IR and SEM results further confirmed the outstanding ability of ChCl-LA due of its ability in cellulose, hemicellulose and lignin disruption, exposing its cellulose fraction to enzymatic hydrolysis. ChCl-LA is also more favorable compare to acid and alkaline solvents as it could prevent sugars loss, use of expensive corrosion resistant equipment and ease products separation.
    Matched MeSH terms: Urea
  18. Fulltext Microcapsules Filled with a Palm Oil-Based Alkyd as Healing Agent for Epoxy Matrix
    Shahabudin N, Yahya R, Gan SN
    Polymers (Basel), 2016 Apr 06;8(4).
    PMID: 30979216 DOI: 10.3390/polym8040125
    One of the approaches to prolong the service lifespan of polymeric material is the development of self-healing ability by means of embedded microcapsules containing a healing agent. In this work, poly(melamine-urea-formaldehyde) (PMUF) microcapsules containing a palm oil-based alkyd were produced by polymerization of melamine resin, urea and formaldehyde that encapsulated droplets of the suspended alkyd particles. A series of spherical and free-flowing microcapsules were obtained. The chemical properties of core and shell materials were characterized by Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and proton nuclear magnetic resonance spectroscopy (¹H-NMR). Differential scanning calorimetry (DSC) analysis showed a glass transition around -15 °C due to the alkyd, and a melting temperature at around 200 °C due to the shell. Thermogravimetric analysis (TGA) results showed that the core and shell thermally degraded within the temperature range of 200⁻600 °C. Field emission scanning electron microscope (FESEM) examination of the ruptured microcapsule showed smooth inner and rough outer surfaces of the shell. Flexural strength and microhardness (Vickers) of the cured epoxy compound were not affected with the incorporation of 1%⁻3% of the microcapsules. The viability of the healing reactions was demonstrated by blending small amounts of alkyd with epoxy and hardener at different ratios. The blends could readily cure to non-sticky hard solids at room temperature and the reactions could be verified by ATR-FTIR.
    Matched MeSH terms: Urea
  19. Field evaluation of newly-developed controlled release fertilizer on rice production and nitrogen uptake
    Mohammad Mu'az Hashim, Mohd Khanif Yusop, Radziah Othman, Samsuri Abd. Wahid
    Sains Malaysiana, 2017;46:925-932.
    Implementation of sound fertilizer management in rice cultivation is essential in optimizing productivity and profitability. The use of controlled release fertilizer (CRF) to improve crop production in various cropping systems has been widely explored, with new approaches and materials continually being studied to produce new CRF. A field study was carried out to determine the efficiency of local CRFs on rice production and N uptake using MR220 CL1 rice variety. Ten different types of CRFs consisting of two groups namely biochar impregnated urea (BIU 300-5, BIU 300-10, BIU 700-5 and BIU 700-10) and palm stearin (PS) coated urea with nitrification inhibitors (PS, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150, PS+Cu and PS+Zn) were used as treatments. Plant height, SPAD reading, 1000-grain weight and harvest index (HI) showed significant improvement in rice treated with both biochar impregnated and palm stearin coated urea. With respect to grain yield, BIU 300-10, BIU 700-5, BIU 700-10, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150 and PS+Cu treatments significantly increased rice yield. The CRFs mostly showed significantly higher N uptake in rice, especially in rice grains, however, there was no significant difference among treatments in soil residual ammonium (NH4+-N). The newly-developed CRFs showed huge potential as an alternative for common urea, especially BIU 700-5, BIU 700-10, PS+DMPP-100 and PS+DMPP-50, in increasing rice grain yield. With proper approaches, these CRFs can contribute in improving rice production to provide sufficient food for ever increasing population.
    Matched MeSH terms: Urea
  20. Effects of different doses of fertilizers on growth and yield components of biodiesel plant (jatropha curcas l.)
    Inam Ali Shah, Sultan Mehmod Wazir, Rahmat Ali Khan
    Sains Malaysiana, 2017;46:117-122.
    Effects of different doses of fertilizers on growth and yield components of biodiesel plant (Jatropha curcas L.), was
    made in the prevailing environment of University of Science and Technology Bannu. The experiment was carried out in
    randomized complete block design (RCBD) with three replications. Nitrogen, phosphorus and potassium were applied
    in the form of urea, single super phosphate and potash in the shape of combined NPK, respectively, during sprouting
    of leaves and thereafter with each irrigation in split doses. The analysis of variance for number of branches per plant
    showed significant results indicated in ANOVA. Significantly the number of primary branches per plant 8.07 was recorded
    in T4 with the application of dose of (N P K: 2507.5 gm: 1091.5 gm: 501.5 gm). Maximum No. of secondary branches
    per plant (9.100) were recorded in T1 especially at both plots. Flower per inflorescence showed that maximum value
    (122.810) was recorded in T5 of especially at both plots. Inflorescence plant-1 showed that maximum value (39.477) were
    recorded in T1 and minimum value were noted as (12.733) at T3 on both the flats. The data for fruits per plant showed
    that maximum value (143.300) was recorded in T1. The seed index, which was the output of the aim of this research work,
    reflects highly significant differences in mean value observed for both subplots. Mean values showed that maximum seeds
    weight 45.86 was recorded in T1 of especially at both plots while low seed index was noted as 22.84 at T5 (N: 3400 gm,
    P: 1480 gm, K: 680 gm) at both the subplots.
    Matched MeSH terms: Urea
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