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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*
Fulltext Nitrogen Pollution Impact and Remediation through Low Cost Starch Based Biodegradable polymers

Ibrahim KA, Naz MY, Shukrullah S, Sulaiman SA, Ghaffar A, AbdEl-Salam NM

Sci Rep, 2020 Apr 03;10(1):5927.
PMID: 32246028 DOI: 10.1038/s41598-020-62793-3

The world does not have too much time to ensure that the fast-growing population has enough land, food, water and energy. The rising food demand has brought a positive surge in fertilizers' demand and agriculture-based economy. The world is using 170 million tons of fertilizer every year for food, fuel, fiber, and feed. The nitrogenous fertilizers are being used to meet 48% of the total food demand of the world. High fertilizer inputs augment the reactive nitrogen levels in soil, air, and water. The unassimilated reactive nitrogen changes into a pollutant and harms the natural resources. The use of controlled-release fertilizers for slowing down the nutrients' leaching has recently been practiced by farmers. However, to date, monitoring of the complete discharge time and discharge rate of controlled released fertilizers is not completely understood by the researchers. In this work, corn starch was thermally processed into a week gel-like coating material by reacting with urea and borate. The granular urea was coated with native and processed starch in a fluidized bed reactor having bottom-up fluid delivery system. The processed starch exhibited better thermal and mechanical stability as compared to the native starch. Unlike the pure starch, the storage modulus of the processed starch dominated the loss modulus. The release time of urea, coated with processed starch, remained remarkably larger than the uncoated urea.

Matched MeSH terms: Urea
13C-Urea Breath Test Accuracy for Helicobacter pylori Infection in the Asian Population: A Meta-Analysis

Abd Rahim MA, Johani FH, Shah SA, Hassan MR, Abdul Manaf MR

Ann Glob Health, 2019 Jul 24;85(1).
PMID: 31348624

BACKGROUND: Helicobacter pylori (H. pylori) infection is known to be associated with peptic ulcer and gastric cancer. Detection of H. pylori infection is a significant part of peptic ulcer and gastric cancer prevention and management. 13C-urea breath test (UBT) provides a good option for the pathogen detection due to its accuracy and safety.
OBJECTIVE: This review aims to evaluate the 13C-UBT diagnostic accuracy studies conducted among Asian population and validate its use for the Asian population.
METHODS: Original articles were systematically searched in PubMed, Scopus, and Google Scholar using the PICOS strategy by applying relevant keywords. Only studies published in English and conducted in Asia were included. Our search returned 276 articles. After assessment, 11 articles which answered our research question and met the criteria set for systematic review and meta-analysis were accepted. A total of 15 study protocols were extracted from the 11 accepted articles.
FINDINGS: Majority of the studies were conducted in Hong Kong (six), followed by Taiwan (five), Japan (two), and one each in Singapore and Israel. All studies had used histology as part of its gold standard of reference. All but one study was performed on adult populations. The summary estimate for sensitivity was 97% (95% CI: 96, 98%), and specificity was 96% (95% CI: 95, 97%), with significant heterogeneity between studies. Adjusting for the dose (50 mg) and breath sample collection time (20 minutes) had improved both accuracy estimates and significantly reduced heterogeneity.
CONCLUSION: This review supports the test-and-treat strategy for H. pylori infection management. Prevalence and cost-effectiveness studies are mandatory for health authorities to adopt this strategy into national policy.

Matched MeSH terms: Urea/analysis*
Fulltext Effects of Supplementation of Mulberry (Morus alba) Foliage and Urea-rice Bran as Fermentable Energy and Protein Sources in Sheep Fed Urea-treated Rice Straw Based Diet

Yulistiani D, Jelan ZA, Liang JB, Yaakub H, Abdullah N

Asian-Australas J Anim Sci, 2015 Apr;28(4):494-501.
PMID: 25656207 DOI: 10.5713/ajas.14.0406

A digestibility study was conducted to evaluate the effects of supplementing mulberry foliage and urea rice-bran as a source of fermentable energy and protein to 12 sheep fed diets based on urea-treated rice straw (TRS). The three dietary treatments were: T1, TRS with mulberry; T2, TRS with 50% mulberry replaced with rice bran and urea; and T3, TRS with rice bran and urea. The study was arranged in a completely randomized design with four replications for each treatment. The sheep were fed one of the three diets and the supplements were offered at 1.2% of the body weight (BW) and the TRS was provided ad libitum. There were no differences (p>0.05) among the three treatment groups with respect to dry matter (DM) intake (76.8±4.2 g/kg BW(0.75)) and DM, organic matter (OM), and crude protein (CP) digestibility (55.3±1.22; 69.9±0.85; 46.3±1.65% respectively for DM, OM, and CP). The digestibility of fiber (neutral detergent fiber [NDF] and acid detergent fiber) was significantly lower (p<0.05) for T3 (46.2 and 46.6 respectively) compared to T1 (55.8 and 53.7 respectively) and T2 (54.1 and 52.8 respectively). Nitrogen (N) intake by sheep on diet T3 was significantly (p<0.05) higher than sheep fed diet T1. However, N balance did not differ among the three diets (3.0±0.32 g/d). In contrast, the rumen ammonia (NH3-N) concentrations in sheep fed T2 and T3 were significantly (p<0.05) higher than in sheep fed T1. The NH3-N concentrations for all three diets were above the critical value required for optimum rumen microbial growth and synthesis. Total volatile fatty acid concentrations were highest (p<0.05) in T1 (120.3 mM), whilst the molar proportion of propionic acid was highest in T3 (36.9%). However, the microbial N supply in sheep fed T1 and T3 was similar but was significantly (p<0.05) higher than for sheep fed T2. It was concluded that mulberry foliage is a potential supplement of fermentable energy and protein for sheep fed TRS based diet. The suggested level of supplementation is 1.2% of BW or 32% of the total diet since it resulted in similar effects on the intake of DM, OM, and NDF, digestibility of DM, OM, and CP, N utilization and microbial supply when compared to rice bran and urea supplementation.

Matched MeSH terms: Urea
Blood parameters and electroencephalographic responses of goats to slaughter without stunning

Sabow AB, Goh YM, Zulkifli I, Sazili AQ, Kaka U, Kadi MZAA, et al.

Meat Sci, 2016 Nov;121:148-155.
PMID: 27317849 DOI: 10.1016/j.meatsci.2016.05.009

The study compared changes in blood biochemistry, hormonal and electroencephalographic indices associated with possible noxious stimuli following neck cut slaughter in conscious, non-anaesthetized versus minimally-anaesthetized goats. Ten male Boer crossbreed goats were assigned into two groups and subjected to either slaughter conscious without stunning (SWS) or slaughter following minimal anaesthesia (SMA). Hormonal responses and changes in electroencephalographic (EEG) parameters were not influenced by slaughter method. The SWS goats had higher glucose and lactate than did SMA goats. It can be concluded that the noxious stimulus from the neck cut is present in both conscious and minimally anaesthetized goats. The application of slaughter without stunning causes changes in the EEG activities that are consistent with the presence of post slaughter noxious sensory input associated with tissue damage and would be expected to be experienced as pain in goats.

Matched MeSH terms: Urea/blood
Fulltext A biosensor for urea from succinimide-modified acrylic microspheres based on reflectance transduction

Ulianas A, Heng LY, Ahmad M

Sensors (Basel), 2011;11(9):8323-38.
PMID: 22164078 DOI: 10.3390/s110908323

New acrylic microspheres were synthesised by photopolymerisation where the succinimide functional group was incorporated during the microsphere preparation. An optical biosensor for urea based on reflectance transduction with a large linear response range to urea was successfully developed using this material. The biosensor utilized succinimide-modified acrylic microspheres immobilized with a Nile blue chromoionophore (ETH 5294) for optical detection and urease enzyme was immobilized on the surface of the microspheres via the succinimide groups. No leaching of the enzyme or chromoionophore was observed. Hydrolysis of the urea by urease changes the pH and leads to a color change of the immobilized chromoionophore. When the color change was monitored by reflectance spectrophotometry, the linear response range of the biosensor to urea was from 0.01 to 1,000 mM (R2 = 0.97) with a limit of detection of 9.97 μM. The biosensor response showed good reproducibility (relative standard deviation = 1.43%, n = 5) with no interference by major cations such as Na+, K+, NH4+ and Mg2+. The use of reflectance as a transduction method led to a large linear response range that is better than that of many urea biosensors based on other optical transduction methods.

Matched MeSH terms: Urea/chemistry*; Urease/chemistry
A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

Alqasaimeh MS, Heng LY, Ahmad M

Sensors (Basel), 2007 Oct 11;7(10):2251-2262.
PMID: 28903225 DOI: 10.3390/s7102251

An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294) and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R² = 0.982, n = 6). The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

Matched MeSH terms: Urea; Urease
Fulltext Development of seed treatments biofertilizer and nutrient uptake study using tracer technique for okra plants

Hoe, Phua Choo Kwai, Khairuddin Abdul Rahim, Ahmad Nazrul Abd Wahid

Jurnal Sains Nuklear Malaysia, 2013;25(1):16-23.
MyJurnal

Development of biofertilizer seed treatments for okra seeds were carried out by mixing phosphate
solubilising bacteria (AP 3) and plant growth promoter (AP 2) with adhesives. The seeds were
coated with inoculums and four types of adhesives namely, Gum Arabic; Polyethylene Glycol
(PEG); Sodium Alginate and Methycellulose respectively. From eight seed treatments, all seed
treatments significantly increased seed germinations except treatment T4 (Gum Arabic and AP3).
In general, maximum germination rates and log of viable cells were observed when treated with
polyethylene glycol 4000 (PEG) mixed with AP2 (T7) and AP3 (T8). These results show that using
PEG as adhesive enhanced the germination rates and log of viable cells of AP2 and AP3. Thus,
PEG could be a good adhesive for seed treatment. In greenhouse experiment, okra seeds treatment
with AP2 and PEG (T1) showed the highest dry weight compared to other treatments. Seeds
treatment with AP3 and PEG (T2) showed higher contribution of N compare to seeds treatment
(T1). There were no significant different within seed treatments and urea treatment in okra yield.
All treatments significantly increased yields compared with control

Matched MeSH terms: Urea
Fulltext Pharmacological Evaluation of Safoof-e-Pathar Phori- A Polyherbal Unani Formulation for Urolithiasis

Ahmad W, Khan MA, Ashraf K, Ahmad A, Daud Ali M, Ansari MN, et al.

Front Pharmacol, 2021;12:597990.
PMID: 33935697 DOI: 10.3389/fphar.2021.597990

Safoof-e-Pathar phori (SPP) is an Unani poly-herbomineral formulation, which has for a long time been used as a medicine due to its antiurolithiatic activity, as per the Unani Pharmacopoeia. This powder formulation is prepared using six different plant/mineral constituents. In this study, we explored the antiurolithiatic and antioxidant potentials of SPP (at 700 and 1,000 mg/kg) in albino Wistar rats with urolithiasis induced by 0.75% ethylene glycol (EG) and 1% ammonium chloride (AC). Long-term oral toxicity studies were performed according to the Organization for Economic Co-operation and Development (OECD) guidelines for 90 days at an oral dose of 700 mg/kg of SPP. The EG urolithiatic toxicant group had significantly higher levels of urinary calcium, serum creatinine, blood urea, and tissue lipid peroxidation and significantly (p < 0.001 vs control) lower levels of urinary sodium and potassium than the normal control group. Histopathological examination revealed the presence of refractile crystals in the tubular epithelial cell and damage to proximal tubular epithelium in the toxicant group but not in the SPP treatment groups. Treatment of SPP at 700 and 1,000 mg/kg significantly (p < 0.001 vs toxicant) lowered urinary calcium, serum creatinine, blood urea, and lipid peroxidation in urolithiatic rats, 21 days after induction of urolithiasis compared to the toxicant group. A long-term oral toxicity study revealed the normal growth of animals without any significant change in hematological, hepatic, and renal parameters; there was no evidence of abnormal histology of the heart, kidney, liver, spleen, or stomach tissues. These results suggest the usefulness of SPP as an antiurolithiatic and an antioxidant agent, and long-term daily oral consumption of SPP was found to be safe in albino Wistar rats for up to 3 months. Thus, SPP may be safe for clinical use as an antiurolithiatic formulation.

Matched MeSH terms: Urea
Fulltext Toxicity Evaluation of the Naphthalen-2-yl 3,5-Dinitrobenzoate: A Drug Candidate for Alzheimer Disease

Anwar F, Saleem U, Rehman AU, Ahmad B, Froeyen M, Mirza MU, et al.

Front Pharmacol, 2021;12:607026.
PMID: 34040515 DOI: 10.3389/fphar.2021.607026

The presented study was designed to probe the toxicity potential of newly identified compound naphthalen-2-yl 3,5-dinitrobenzoate (SF1). Acute, subacute toxicity and teratogenicity studies were performed as per Organization of economic cooperation and development (OECD) 425, 407, and 414 test guidelines, respectively. An oral dose of 2000 mg/kg to rats for acute toxicity. Furthermore, 5, 10, 20, and 40 mg/kg doses were administered once daily for 28 days in subacute toxicity study. Teratogenicity study was performed with 40 mg/kg due to its excellent anti-Alzheimer results at this dose. SF1 induced a significant rise in Alkaline Phosphatases (ALP), bilirubin, white blood cells (WBC), and lymphocyte levels with a decrease in platelet count. Furthermore, the reduction in urea, uric acid, and aspartate transaminase (AST) levels and an increase in total protein levels were measured in subacute toxicity. SF1 increased spermatogenesis at 5 and 10 mg/kg doses. Teratogenicity study depicted no resorptions, early abortions, cleft palate, spina bifida and any skeletal abnormalities in the fetuses. Oxidative stress markers (Superoxide dismutase (SOD), Catalase (CAT), and glutathione (GSH) were increased in all the experiments, whereas the effect on melanoaldehyde Malondialdehyde (MDA) levels was variable. Histopathology further corroborated these results with no change in the architectures of selected organs. Consequently, a 2000 mg/kg dose of SF1 tends to induce minor liver dysfunction along with immunomodulation, and it is well below its LD
50
. Moreover, it can be safely used in pregnancy owing to its no detectable teratogenicity.

Matched MeSH terms: Urea
Azostix: a rapid test for blood urea

Buttery JE, de Witt GF, Ahmad UO

Med J Malaya, 1969 Jun;23(4):265-8.
PMID: 4242173
Matched MeSH terms: Blood Urea Nitrogen*
Fulltext Mefenamic Acid induced nephrotoxicity: an animal model

Somchit MN, Sanat F, Hui GE, Wahab SI, Ahmad Z

Adv Pharm Bull, 2014 Dec;4(4):401-4.
PMID: 25436198 DOI: 10.5681/apb.2014.059

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are used for the treatment of many joint disorders, inflammation and to control pain. Numerous reports have indicated that NSAIDs are capable of producing nephrotoxicity in human. Therefore, the objective of this study was to evaluate mefenamic acid, a NSAID nephrotoxicity in an animal model.
METHODS: Mice were dosed intraperitoneally with mefenamic acid either as a single dose (100 or 200 mg/kg in 10% Dimethyl sulfoxide/Palm oil) or as single daily doses for 14 days (50 or 100 mg/kg in 10% Dimethyl sulfoxide/Palm oil per day). Venous blood samples from mice during the dosing period were taken prior to and 14 days post-dosing from cardiac puncture into heparinized vials. Plasma blood urea nitrogen (BUN) and creatinine activities were measured.
RESULTS: Single dose of mefenamic acid induced mild alteration of kidney histology mainly mild glomerular necrosis and tubular atrophy. Interestingly, chronic doses induced a dose dependent glomerular necrosis, massive degeneration, inflammation and tubular atrophy. Plasma blood urea nitrogen was statistically elevated in mice treated with mefenamic acid for 14 days similar to plasma creatinine.
CONCLUSION: RESULTS from this study suggest that mefenamic acid as with other NSAIDs capable of producing nephrotoxicity. Therefore, the study of the exact mechanism of mefenamic acid induced severe nephrotoxicity can be done in this animal model.

Matched MeSH terms: Blood Urea Nitrogen
Impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations among patients with acetaminophen overdose

Zyoud SH, Awang R, Sulaiman SA, Al-Jabi SW

Pharmacoepidemiol Drug Saf, 2011 Feb;20(2):203-8.
PMID: 21254292 DOI: 10.1002/pds.2060

Acetaminophen overdose may be accompanied by electrolyte disturbances. The basis for electrolyte change appears to be due to increased fractional urinary electrolyte excretion.

Matched MeSH terms: Urea/blood*
Diallyl sulphide, a component of garlic, abrogates ferric nitrilotriacetate-induced oxidative stress and renal damage in rats

Ansar S, Iqbal M, AlJameil N

Hum Exp Toxicol, 2014 Dec;33(12):1209-16.
PMID: 24596035 DOI: 10.1177/0960327114524237

Ferric nitrilotriacetate (Fe-NTA) induces tissue necrosis as a result of lipid peroxidation (LPO) and oxidative damage that leads to high incidence of renal carcinomas. The present study was undertaken to evaluate the effect of diallyl sulphide (DAS) against Fe-NTA-induced nephrotoxicity. A total of 30 healthy male rats were randomly divided into 5 groups of 6 rats each: (1) control, (2) DAS (200 mg kg(-1)), (3) Fe-NTA (9 g Fe kg(-1)), (4) DAS (100 mg kg(-1)) + Fe-NTA (9 mg Fe kg(-1)) and (5) DAS (200 mg kg(-1)) + Fe-NTA (9 mg Fe kg(-1)). Fe-NTA + DAS-treated groups were given DAS for a period of 1 week before Fe-NTA administration. The intraperitoneal administration of Fe-NTA enhanced blood urea nitrogen and creatinine levels with reduction in levels of antioxidant enzymes. However, significant restoration of depleted renal glutathione and its dependent enzymes (glutathione reductase and glutathione-S-transferase) was observed in DAS pretreated groups. DAS also attenuated Fe-NTA-induced increase in LPO, hydrogen peroxide generation and protein carbonyl formation (p < 0.05). The results indicate that DAS may be beneficial in ameliorating the Fe-NTA-induced renal oxidative damage in rats.

Matched MeSH terms: Blood Urea Nitrogen
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
Fulltext Statistical optimisation of process parameters on the efficiency of N-TiO2 dye sensitised solar cell using response surface methodology (RSM)

Samaila, Buda, Suhaidi Shafie, Suraya Abdul Rashid, Haslina Jafaar, Ali Khalifa

Pertanika Journal of Science & Technology, 2017;25(101):111-118.
MyJurnal

In this study, nitrogen doped titanium dioxide-based dye-sensitised solar cell was successfully fabricated
using screen printing technique to discover the optimisation of process parameters for the solar cell
efficiency using response surface methodology (RSM). Parameter optimisation has been a major concern
in solar cell fabrication. The selected parameters were: nitrogen concentration (15-25 mg of urea), the
film thickness (25-60 µm) and dye loading time (12-24 hours), the optimum condition which yields the
highest efficiency of 3.5% was at 15 mg nitrogen concentration, 25 µm film thickness and 24-hours dye
loading time. Film thickness was found to have a significant influence on efficiency while the loading
time exceeding 18 hours has the least significant effect.

Matched MeSH terms: Urea
Chemically crosslinked hydrogel and its driving force towards superabsorbent behaviour

Salleh KM, Zakaria S, Sajab MS, Gan S, Chia CH, Jaafar SNS, et al.

Int J Biol Macromol, 2018 Oct 15;118(Pt B):1422-1430.
PMID: 29964115 DOI: 10.1016/j.ijbiomac.2018.06.159

Dissolved oil palm empty fruit bunch (EFB) cellulose in NaOH/urea solvent was mixed with sodium carboxymethylcellulose (NaCMC) to form a green regenerated superabsorbent hydrogel. The effect of concentration of epichlorohydrin (ECH) as the crosslinker on the formation, physical, and chemical properties of hydrogel was studied. Rapid formation and higher gel content of hydrogel were observed at 10% concentration of ECH. The superabsorbent hydrogel was successfully fabricated in this study with the swelling ability >100,000%. Hydrogel with higher concentration of ECH showed opposite trend by having higher superabsorbent property than that of lower concentration. The covalent bond of COC was observed with Attenuated total reflectance fourier transform infrared (ATR-FT-IR) spectroscopy to confirm the occurrence of crosslinking. The physical and chemical properties of hydrogel were affected by swelling phenomenon. Hydrogel with higher degree of swelling exhibited lower moisture retention and higher transparency. Moreover, the weight of the superabsorbent hydrogel increased with the decrement of pH value of external media (distilled water). This study provided substantial information on the effect of different percentage of ECH as crosslinker on hydrogel basic properties. Furthermore, this study affords correlation of many essential driving forces that affected hydrogel superabsorbent property.

Matched MeSH terms: Urea/chemistry
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
Correlation between serum urea and salivary urea

Sein KT, Arumainayagam G

Clin Chem, 1987 Dec;33(12):2303-4.
PMID: 3690853
Matched MeSH terms: Urea/analysis*; Urea/blood
Fulltext Physico-mechanical properties and formaldehyde emission of rubberwood particleboard made with UF resin admixed with ammonium and aluminium-based hardeners

Abd Ghani Aizat, Paiman, Bawon, Lee, Seng Hua, Ashaari Zaidon

Pertanika Journal of Science & Technology, 2019;27(1):473-488.
MyJurnal

In this study, the effects of addition of ammonium and aluminium-based hardeners into
urea formaldehyde resin (UF) on the physico-mechanical properties and formaldehyde
emission of the rubberwood particleboard were investigated. Four types of hardeners,
namely ammonium chloride (AC), ammonium sulphate (AS), aluminium chloride (AlC)
and aluminium sulphate (AlS), were added into UF resin. The acidity, gelation time,
viscosity and free formaldehyde content of the UF/hardener mixtures were determined.
Particleboard made with the UF/hardener mixtures were tested for physico-mechanical
properties and formaldehyde emission. The pH values of the resin after addition of
aluminium-based hardeners were higher and resulted in higher viscosity and shorter
gelation time. Consequently, despite lower formaldehyde emission was recorded, the
physico-mechanical properties of the resulted particleboard were inferior compared to
that of ammonium-based hardeners. The best quality particleboard in terms of mechanical,
physical and formaldehyde emission were obtained from the particleboard made with AS,
followed by AC.

Matched MeSH terms: Urea

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