Displaying publications 21 - 40 of 406 in total

Abstract:
Sort:
  1. Direct recovery of cyclodextringlycosyltransferase from Bacillus cereus using aqueous two-phase flotation
    Lin YK, Show PL, Yap YJ, Tan CP, Ng EP, Ariff AB, et al.
    J Biosci Bioeng, 2015 Dec;120(6):684-9.
    PMID: 26111602 DOI: 10.1016/j.jbiosc.2015.04.013
    Purification of cyclodextrin glycosyl transferase (CGTase) from Bacillus cereus using polyethylene glycol (PEG)-potassium phosphates aqueous two-phase flotation (ATPF) system was studied in this paper. The effects of varying PEG molecular weight, tie-line length (TLL) value, volume ratio (VR), pH value, crude concentration and gas nitrogen flotation time were investigated. The optimal condition for purification of CGTase was attained at 18.0% (w/w) PEG 8000, 7.0% (w/w) potassium phosphates, VR of 3.0, 20% (w/w) crude load at pH 7, and 80 min nitrogen flotation time at a flow rate of 5 L/min. With this optimal condition, purification factor (PFT) of 21.8 and a yield (YT) of 97.1% were attained. CGTase was successfully purified in a single downstream processing step using the ATPF.
    Matched MeSH terms: Potassium; Potassium Compounds
  2. Community-level dietary intake of sodium, potassium, and sodium-to-potassium ratio as a global public health problem: a systematic review and meta-analysis
    Farapti F, Maulia PH, Fadilla C, Yogiswara N, Rejeki PS, Miftahussurur M, et al.
    F1000Res, 2022;11:953.
    PMID: 40190487 DOI: 10.12688/f1000research.122560.2
    Background: Widespread adoption of a westernized diet represents a major lifestyle change characterized by substantially higher sodium consumption and lower potassium intake, which is related to cardiovascular morbidity. Methods: We performed a systematic review and meta-analysis over published studies in accordance with quantifying the dietary intake of sodium and potassium of the universal population across the world. The PubMed, EMBASE, Cochrane Library, and Google Scholar databases were used to find research that pronounced 24-hour urinary sodium or potassium excretion (reference period: 2014-2021). The effect size was estimated using the fixed-effect model; sub-group analysis become accomplished to determine urinary sodium and potassium excretion disaggregated by geographical location. Publication bias became evaluated the usage of graphical funnel plot. Data analysis was performed using STATA 16. Results: Forty-three studies (n= 62,940) qualified the selection criteria. The mean urinary excretion of sodium and potassium was 156.73 mmol/24h [95% confidence interval (CI), 148.98-164.47] and 48.89 mmol/24 h (95% CI, 43.61-54.17), respectively; the mean urinary sodium/potassium ratio was 3.68 (95% CI, 2.96-4.40). Conclusions: This updated systematic review highlights excessively high dietary intake of sodium and low intake of potassium at the community level in most parts of the world. The urinary Na/K ratio exceeded the level recommended by the WHO guidelines.
    Matched MeSH terms: Potassium, Dietary*
  3. The status of natural radioactivity in Nigerian environments
    Olatunji MA, Khandaker MU, Nwankwo VUJ, Idris AM
    Radiat Environ Biophys, 2022 Nov;61(4):597-608.
    PMID: 36175773 DOI: 10.1007/s00411-022-00993-3
    Proper documentation of baseline radiation data of different environments is an important step toward adequate environmental monitoring, and it provides quick means to quantitatively check and determine possible radionuclide contamination by anthropogenic sources. Besides, such documentation is useful for decision making processes, assessment of dose rates to the public, epidemiological studies, and environmental regulations. This review summarizes the results of studies conducted on radioactivity in Nigerian environments. For most soil samples, the levels of radioactivity are well within the world averages of 33, 45, and 420 Bq kg-1 for 226Ra, 232Th and 40K, respectively. Other soil samples from regions such as Abeokuta in the southwest, and Jos in the northcentral have been described as high background radiation areas with radioactivity values comparable with those obtained from known high background radiation areas such as the Odisha (formerly Orissa) coast in India (with values reported as 350, 2,825, and 180 Bq kg-1 for 238U/226Ra, 232Th, and 40K, respectively). In some parts of Nigeria, surface and underground water sources used for drinking and other purposes also present elevated levels of 226Ra above the world range of 0.01 to 0.1 Bq l-1 and the tolerable levels recommended by the World Health Organization and U.S. Environmental Protection Agency. Corresponding radiation doses due to measured radioactivities from different environments were estimated and compared with those reported in similar studies around the world. More so, the human and environmental health hazards that might be associated with the reported radioactivity in different environmental settings are discussed. The present report is expected to support authorities in developing appropriate regulations to protect the public from radiation exposure arising from environmental radioactivity. The report also examines other areas of consideration for future studies to ensure adequate radiation monitoring in Nigeria.
    Matched MeSH terms: Potassium Radioisotopes/analysis
  4. Fulltext Controlled image-based prediction of soil nutrient concentrations (NPK) using machine and deep learning
    Maqsood U, Karamat Ullah Khan T, Jhanjhi NZ, Sattar K, Iftikhar F, Imtiaz Ali N, et al.
    PLoS One, 2026;21(10):e0360517.
    PMID: 42945351 DOI: 10.1371/journal.pone.0360517
    Soil nutrient analysis is essential for sustainable agriculture and precision farming. Traditional chemical tests for nitrogen, phosphorus, and potassium are reliable but costly, time-consuming, and often unavailable in remote areas. The objective of this study is to develop a novel approach that combines laboratory chemical extraction, controlled image acquisition, image processing, machine learning, and deep learning to classify soil nitrogen, phosphorus, and potassium levels. 50 independent soil samples were analyzed, chemically extracted, and classified as Low, Medium, or High for each nutrient. A specially designed black-box prototype was developed to capture high-quality images of soil extract samples under consistent lighting conditions. The images were used to extract color and texture information, which was evaluated using multiple classical machine-learning algorithms, such as K-nearest neighbours, support vector machines, logistic regression, random forest, extra trees, gradient boosting, and Gaussian naive Bayes. A convolutional neural network-based model was also used for comparison. To minimize data leakage, all validation procedures were performed at the physical-sample level, and augmented images were restricted to the training data. The best models obtained using nested cross-validation for nitrogen, phosphorus, and potassium were KNN, Random Forest, and Logistic Regression, respectively, with accuracies of 60%, 82%, and 48%. The nitrogen model correctly identified the High category, and the phosphorus model correctly identified the dominant Low category each time. For potassium, Logistic Regression made predictions of all three classes and outperformed the majority class baseline. The Classical machine-learning models slightly outperformed the compact CNN for nitrogen and potassium, while both achieved the same accuracy for phosphorus; however, overall performance remained limited by the small and imbalanced dataset. The findings suggest that the proposed framework could contribute to image-assisted decision-making in smart farming and support improved soil management practices, particularly in regions where laboratory testing facilities are limited.
    Matched MeSH terms: Potassium/analysis
  5. A Survey on Nutrition Labeling for Sodium, Potassium, and Phosphorus of Packaged Food and Beverages
    Asan NB, Wei Kun DW, Ooi YBH, Khor BH
    J Ren Nutr, 2025 Jan;35(1):229-233.
    PMID: 38848805 DOI: 10.1053/j.jrn.2024.05.006
    OBJECTIVES: Nutrition labeling is important to guide patients with chronic kidney disease to make informed choices. This study aimed to evaluate the extent and accessibility of nutrition labeling for sodium, potassium, and phosphorus on food and beverage products in a supermarket.

    METHODS: A cross-sectional survey was conducted in a Malaysian supermarket. Information on sodium, potassium, and phosphorus contents was collected from the nutrition fact panel, while information on food additives containing sodium, potassium, and phosphorus was collected from the ingredient list.

    RESULTS: The survey included 2,577 foods and beverages, and 79.4% of the products included sodium information in nutrition fact panels, but only 11.7% and 2.0% disclosed potassium and phosphorus content, respectively. Sodium-containing additives were found in 78.6% of products; potassium- and phosphorus-containing additives were reported in 28.5% and 46.9% of products, respectively. Sodium-containing additives were typically listed as "salt," potassium-containing additives as "alternative names," and phosphorus-containing additives as "starch" and "E numbers." Imported products were more likely to include sodium (P potassium and phosphorus information on nutrition labels in Malaysia food and beverage products, which presents significant challenges for individuals with chronic kidney disease in choosing appropriate products for their dietary needs.

    Matched MeSH terms: Potassium/analysis
  6. Investigation of natural radionuclide and associated radiological parameters of selected construction materials used in Nepal
    Upadhyay DR, Shah BR, Tajudin SM, Khanal R
    Environ Monit Assess, 2025 May 08;197(6):639.
    PMID: 40338326 DOI: 10.1007/s10661-025-14099-y
    The present study investigated the natural radioactivity levels of 226 Ra, 232 Th, and 40 K in various construction and building materials commonly used in Central Nepal, expressed in Bq kg - 1 , and analyzed the associated 13 radiological parameters for the evaluation of risks. Activity concentrations were determined using a thallium-activated sodium iodide crystal NaI(Tl) 3" × 3" scintillator detector. Multivariate statistical analysis was used to discern trends and depict the data. Among the material studied, granites, sand, and bricks exhibited concentrations and associated radiological parameters that exceeded world average. However, remaining aggregate, cement, concrete bricks, marble, and tiles showed activity concentrations and hazard indices comparable to or lower than the global average value reported by UNSCEAR, 1993 for building materials. The overall revealed mean ± S.D. concentration of 226 Ra, 232 Th and 40 K across 41 different materials as 43.2 ± 1.0 Bq kg - 1 , 56.8 ± 1.4 Bq kg - 1 , and 281.1 ± 5.3 Bq kg - 1 , respectively. The average values 226 Ra, 232 Th were above the world population average values of 50 and 50 Bq kg - 1 whereas the concentration of 40 K was well below the average value 500 Bq kg - 1 respectively. From this, it is concluded that the studied samples are safe to use. However, regulations are needed to evaluate the natural activity concentrations of radionuclides in geologically derived samples and the associated health implications related to materials utilized from the internal resources of the country and imported materials from a different country.
    Matched MeSH terms: Potassium Radioisotopes/analysis
  7. Determination of radiation hazard arising from the 40K content of bottled mineral water in Malaysia
    Samat S, Evans C
    Sains Malaysiana, 2011;40:1355-1358.
    Eleven different brands of mineral water available in Malaysia were assessed in comparison with two criteria for ingested radiation dose. It is concluded that mineral water can only contribute a very small fraction of the typical daily intake of potassium, and that the radiation dose acquired from any of the brands can never exceed a small fraction of the recommended limits.
    Matched MeSH terms: Potassium
  8. Analisis prestasi nutrien pengkomposan sisa industri sawit bagi skala industri dalam tempoh tiga tahun
    Asis T, Zahrim AY, Assis K
    Sains Malaysiana, 2017;46:1201-1210.
    Pengkomposan tandan buah kosong (EFB) dan sisa efluen kilang (POME) merupakan pendekatan lestari bagi menukarkan EFB dan POME kepada baja kompos. Pengkomposan adalah satu proses biologi yang memerlukan pengawalan yang optimum agar nutrien yang terhasil adalah tinggi dan stabil. Cabaran utama yang dihadapi oleh industri kompos ialah untuk menghasilkan kompos yang bernutrien tinggi dan stabil. Objektif kajian ini ialah untuk menganalisis prestasi jangka panjang bagi loji kompos terpilih melalui kandungan nutrien kompos yang dihasilkan. Penyelidikan ini mengkaji prestasi tiga tahun bagi empat loji kompos di Malaysia iaitu loji kompos Merotai, loji kompos Binuang, loji kompos Tanah Merah dan loji kompos Elphil. Prestasi kandungan nutrien yang diambil kira termasuklah nitrogen, kalium, nisbah karbon kepada nitrogen, kandungan kelembapan dan agregat kompos. Sebanyak 1,465 set data nutrien dianalisis secara deskriptif. Secara keseluruhannya, prestasi kandungan nutrien kesemua loji kompos yang dikaji berjaya memenuhi keperluan minimum industri sawit. Namun terdapat kes kompos yang dihasilkan mengandungi nutrien kalium yang tidak mencapai keperluan minimum industri dan kandungan kelembapan kompos yang tinggi. Kesimpulannya, masih terdapat ruang untuk penambahbaikan dalam proses pengkomposan agar kompos yang dihasilkan mengandungi nutrien yang stabil dan memenuhi keperluan minimum industri
    Matched MeSH terms: Potassium
  9. Hypokalaemic periodic paralysis secondary to subclinical hyperthyroidism: an uncommon cause of acute muscle paralysis
    Payus AO, Liew SL, Tiong N, Mustafa N
    BMJ Case Rep, 2021 Jun 24;14(6).
    PMID: 34167974 DOI: 10.1136/bcr-2020-240666
    Hypokalaemic periodic paralysis secondary to subclinical hyperthyroidism is an uncommon clinical phenomenon characterised by lower limb paralysis secondary to hypokalaemia in the background of subclinical hyperthyroidism. In this article, we report a patient who presented with progressive lower limb muscle weakness secondary to hypokalaemia that was refractory to potassium replacement therapy. He has no diarrhoea, no reduced appetite and was not taking any medication that can cause potassium wasting. Although he was clinically euthyroid, his thyroid function test revealed subclinical hyperthyroidism. His 24-hour urine potassium level was normal, which makes a rapid transcellular shift of potassium secondary to subclinical hyperthyroidism as the possible cause. He was successfully treated with potassium supplements, non-selective beta-blockers and anti-thyroid medication. This case report aimed to share an uncommon case of hypokalaemic periodic paralysis secondary to subclinical hyperthyroidism, which to our knowledge, only a few has been reported in the literature.
    Matched MeSH terms: Potassium
  10. Fulltext Rationale and Design of the Efficacy of a Standardized Diuretic Protocol in Acute Heart Failure Study
    Dauw J, Lelonek M, Zegri-Reiriz I, Paredes-Paucar CP, Zara C, George V, et al.
    ESC Heart Fail, 2021 Dec;8(6):4685-4692.
    PMID: 34708555 DOI: 10.1002/ehf2.13666
    AIMS: Although acute heart failure (AHF) with volume overload is treated with loop diuretics, their dosing and type of administration are mainly based upon expert opinion. A recent position paper from the Heart Failure Association (HFA) proposed a step-wise pharmacologic diuretic strategy to increase the diuretic response and to achieve rapid decongestion. However, no study has evaluated this protocol prospectively.

    METHODS AND RESULTS: The Efficacy of a Standardized Diuretic Protocol in Acute Heart Failure (ENACT-HF) study is an international, multicentre, non-randomized, open-label, pragmatic study in AHF patients on chronic loop diuretic therapy, admitted to the hospital for intravenous loop diuretic therapy, aiming to enrol 500 patients. Inclusion criteria are as follows: at least one sign of volume overload (oedema, ascites, or pleural effusion), use ≥ 40 mg of furosemide or equivalent for >1 month, and a BNP > 250 ng/L or an N-terminal pro-B-type natriuretic peptide > 1000 pg/L. The study is designed in two sequential phases. During Phase 1, all centres will treat consecutive patients according to the local standard of care. In the Phase 2 of the study, all centres will implement a standardized diuretic protocol in the next cohort of consecutive patients. The protocol is based upon the recently published HFA algorithm on diuretic use and starts with intravenous administration of two times the oral home dose. It includes early assessment of diuretic response with a spot urinary sodium measurement after 2 h and urine output after 6 h. Diuretics will be tailored further based upon these measurements. The study is powered for its primary endpoint of natriuresis after 1 day and will be able to detect a 15% difference with 80% power. Secondary endpoints are natriuresis and diuresis after 2 days, change in congestion score, change in weight, in-hospital mortality, and length of hospitalization.

    CONCLUSIONS: The ENACT-HF study will investigate whether a step-wise diuretic approach, based upon early assessment of urinary sodium and urine output as proposed by the HFA, is feasible and able to improve decongestion in AHF with volume overload.

    Matched MeSH terms: Sodium Potassium Chloride Symporter Inhibitors
  11. Fulltext Durian induced hyperkalaemia
    Leo CL, Leong WS, Tieh CS, Liew CK
    Med J Malaysia, 2011 Mar;66(1):66-7.
    PMID: 23765149 MyJurnal
    Hyperkalaemia is a life threatening acute medical emergency. Patients with end stage renal failure are more prone to get hyperkalaemia as potassium is normally excreted via the kidneys. Therefore, patients with end stage renal failure should avoid food with high potassium contents. Bananas are well known to have high potassium content. However, the 'king of fruits' the durian, has higher potassium content compared to bananas. We describe a case of life threatening hyperkalaemia in a lady with end stage renal failure who ate durians prior to her presentation.
    Matched MeSH terms: Potassium
  12. Utilization of rice husks as a feedstock for preparation of activated carbon by microwave induced KOH and K2CO3 activation
    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/chemistry*; Potassium Compounds/chemistry*
  13. Concentration of radiocaesium 137Cs and 134Cs in sediments of the Malaysian marine environment
    Yii MW, Zaharudin A, Norfaizal M
    Appl Radiat Isot, 2007 Dec;65(12):1389-95.
    PMID: 17697782
    The concentrations of 137Cs and 134Cs in Malaysian marine sediments were measured by gamma-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyzer. In general, the 137Cs concentration in Malaysian marine sediments has been found to be very low and less than 5 Bq/kg dry weight with the exception of those from a few sampling locations. The concentration of 134Cs was found to be less than the minimum detectable activity for the measuring condition used. Data reported in this paper were found to be comparable with results from within the region and thus can be used as reference data for the country.
    Matched MeSH terms: Potassium Radioisotopes
  14. A Patient with Hypokalemia and Hypoxemia-What Is the Culprit?
    Lai YY, Lim CH, Nazli MS, Samsudin IN, Thambiah SC
    Clin Chem, 2023 Nov 02;69(11):1220-1225.
    PMID: 37932109 DOI: 10.1093/clinchem/hvad158
    Matched MeSH terms: Potassium
  15. Fulltext Drug utilization review of potassium chloride injection formulations available in a private hospital in kuching, sarawak, malaysia
    Melissa MH, Azmi S
    Malays J Med Sci, 2013 Jul;20(4):47-55.
    PMID: 24043996 MyJurnal
    The concentrated potassium chloride injection is a high-alert medication and replacing it with a pre-mixed formulation can reduce the risks associated with its use. The aim of this study was to determine the clinical characteristics of patients receiving different potassium chloride formulations available at a private institution. The study also assessed the effectiveness and safety of pre-mixed formulations in the correction of hypokalaemia.
    Matched MeSH terms: Potassium Chloride
  16. Fulltext Cardiac Potassium Channels: Physiological Insights for Targeted Therapy
    Jeevaratnam K, Chadda KR, Huang CL, Camm AJ
    J Cardiovasc Pharmacol Ther, 2018 03;23(2):119-129.
    PMID: 28946759 DOI: 10.1177/1074248417729880
    The development of novel drugs specifically directed at the ion channels underlying particular features of cardiac action potential (AP) initiation, recovery, and refractoriness would contribute to an optimized approach to antiarrhythmic therapy that minimizes potential cardiac and extracardiac toxicity. Of these, K+ channels contribute numerous and diverse currents with specific actions on different phases in the time course of AP repolarization. These features and their site-specific distribution make particular K+ channel types attractive therapeutic targets for the development of pharmacological agents attempting antiarrhythmic therapy in conditions such as atrial fibrillation. However, progress in the development of such temporally and spatially selective antiarrhythmic drugs against particular ion channels has been relatively limited, particularly in view of our incomplete understanding of the complex physiological roles and interactions of the various ionic currents. This review summarizes the physiological properties of the main cardiac potassium channels and the way in which they modulate cardiac electrical activity and then critiques a number of available potential antiarrhythmic drugs directed at them.
    Matched MeSH terms: Potassium Channels/drug effects; Potassium Channels/metabolism*; Potassium Channel Blockers/therapeutic use
  17. Fulltext Multiple targets for flecainide action: implications for cardiac arrhythmogenesis
    Salvage SC, Chandrasekharan KH, Jeevaratnam K, Dulhunty AF, Thompson AJ, Jackson AP, et al.
    Br J Pharmacol, 2018 Apr;175(8):1260-1278.
    PMID: 28369767 DOI: 10.1111/bph.13807
    Flecainide suppresses cardiac tachyarrhythmias including paroxysmal atrial fibrillation, supraventricular tachycardia and arrhythmic long QT syndromes (LQTS), as well as the Ca2+ -mediated, catecholaminergic polymorphic ventricular tachycardia (CPVT). However, flecainide can also exert pro-arrhythmic effects most notably following myocardial infarction and when used to diagnose Brugada syndrome (BrS). These divergent actions result from its physiological and pharmacological actions at multiple, interacting levels of cellular organization. These were studied in murine genetic models with modified Nav channel or intracellular ryanodine receptor (RyR2)-Ca2+ channel function. Flecainide accesses its transmembrane Nav 1.5 channel binding site during activated, open, states producing a use-dependent antagonism. Closing either activation or inactivation gates traps flecainide within the pore. An early peak INa related to activation of Nav channels followed by rapid de-activation, drives action potential (AP) upstrokes and their propagation. This is diminished in pro-arrhythmic conditions reflecting loss of function of Nav 1.5 channels, such as BrS, accordingly exacerbated by flecainide challenge. Contrastingly, pro-arrhythmic effects attributed to prolonged AP recovery by abnormal late INaL following gain-of-function modifications of Nav 1.5 channels in LQTS3 are reduced by flecainide. Anti-arrhythmic effects of flecainide that reduce triggering in CPVT models mediated by sarcoplasmic reticular Ca2+ release could arise from its primary actions on Nav channels indirectly decreasing [Ca2+ ]i through a reduced [Na+ ]i and/or direct open-state RyR2-Ca2+ channel antagonism. The consequent [Ca2+ ]i alterations could also modify AP propagation velocity and therefore arrhythmic substrate through its actions on Nav 1.5 channel function. This is consistent with the paradoxical differences between flecainide actions upon Na+ currents, AP conduction and arrhythmogenesis under circumstances of normal and increased RyR2 function.

    LINKED ARTICLES: This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.

    Matched MeSH terms: Potassium Channels/physiology; Potassium Channel Blockers/pharmacology*; Potassium Channel Blockers/therapeutic use
  18. Genetic polymorphisms in KCNQ1, HERG, KCNE1 and KCNE2 genes in the Chinese, Malay and Indian populations of Singapore
    Koo SH, Ho WF, Lee EJ
    Br J Clin Pharmacol, 2006 Mar;61(3):301-8.
    PMID: 16487223
    To determine the genetic variability of long QT syndrome (LQTS)-associated genes (KCNQ1, HERG, KCNE1 and KCNE2) among three distinct ethnic groups in the Singapore population.
    Matched MeSH terms: Potassium Channels, Voltage-Gated/genetics*; Ether-A-Go-Go Potassium Channels/genetics; KCNQ1 Potassium Channel/genetics
  19. Fulltext Removal of hydrogen sulfide from a biogas mimic by using impregnated activated carbon adsorbent
    Zulkefli NN, Masdar MS, Wan Isahak WNR, Md Jahim J, Md Rejab SA, Chien Lye C
    PLoS One, 2019;14(2):e0211713.
    PMID: 30753209 DOI: 10.1371/journal.pone.0211713
    Adsorption technology has led to the development of promising techniques to purify biogas, i.e., biomethane or biohydrogen. Such techniques mainly depend on the adsorbent ability and operating parameters. This research focused on adsorption technology for upgrading biogas technique by developing a novel adsorbent. The commercial coconut shell activated carbon (CAC) and two types of gases (H2S/N2 and H2S/N2/CO2) were used. CAC was modified by copper sulfate (CuSO4), zinc acetate (ZnAc2), potassium hydroxide (KOH), potassium iodide (KI), and sodium carbonate (Na2CO3) on their surface to increase the selectivity of H2S removal. Commercial H2S adsorbents were soaked in 7 wt.% of impregnated solution for 30 min before drying at 120°C for 24 h. The synthesized adsorbent's physical and chemical properties, including surface morphology, porosity, and structures, were characterized by SEM-EDX, FTIR, XRD, TGA, and BET analyses. For real applications, the modified adsorbents were used in a real-time 0.85 L single-column adsorber unit. The operating parameters for the H2S adsorption in the adsorber unit varied in L/D ratio (0.5-2.5) and feed flow rate (1.5-5.5 L/min) where, also equivalent with a gas hourly space velocity, GHSV (212.4-780.0 hour-1) used. The performances of H2S adsorption were then compared with those of the best adsorbent that can be used for further investigation. Characterization results revealed that the impregnated solution homogeneously covered the adsorbent surface, morphology, and properties (i.e., crystallinity and surface area). BET analysis further shows that the modified adsorbents surface area decreased by up to 96%. Hence, ZnAc2-CAC clarify as the best adsorption capacity ranging within 1.3-1.7 mg H2S/g, whereby the studied extended to adsorption-desorption cycle.
    Matched MeSH terms: Potassium Iodide; Potassium Compounds
  20. Study of Primordial 226Ra, 228Ra, and 40K Concentrations in Dietary Palm Dates and Concomitant Radiological Risk
    Khandaker MU, Shuaibu HK, Alklabi FAA, Alzimami KS, Bradley DA
    Health Phys, 2019 06;116(6):789-798.
    PMID: 30889102 DOI: 10.1097/HP.0000000000001042
    The presence of natural radionuclides in the food chain point to a need to assess concentration levels and concomitant radiological risk. Highly popular and forming a staple part of the diet in North Africa, the Arabian Peninsula, and West Asia, palm dates growing naturally there have even greater marketability than simple satisfaction of domestic demand, the palm dates representing a valuable export item. Accurate knowledge of the levels of natural radioactivity in the fruit is thus of importance. In this study, using high-purity germanium gamma-ray spectrometry, quantification has been made of natural radionuclide concentrations in imported dates originating from Iran, Saudi Arabia, and Tunisia. Sample analyses reveal respective mean activity concentrations of 1.4 ± 0.3, 0.8 ± 0.4, and 186 ± 9 Bq kg dry weight for Ra, Ra, and K. For each nuclide, the mean concentration varies little between the dates of the three represented regions. The estimated committed effective dose resulting from the consumption of date fruits for a typical adult was found to be 29.9 μSv y, well below the global internal dose of 290 μSv y assessed by the United Nations Scientific Committee on the Effects of Atomic Radiation to be due to food and water intake. Similarly, the excess lifetime cancer risk due to naturally occurring radioactive material exposure via date fruit consumption is seen to be below the International Commission on Radiological Protection cancer risk factor of 2.5 × 10 based on the additional annual dose limit of 1 mSv for a member of the general public. The results show no significant uptake in the analyzed date fruits.
    Matched MeSH terms: Potassium Radioisotopes/analysis*
Related Terms
Filters
Contact Us

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

External Links