Displaying publications 81 - 100 of 640 in total

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  1. Hidayat T, Ahmad A, Ngo HC
    PeerJ Comput Sci, 2024;10:e1806.
    PMID: 38435549 DOI: 10.7717/peerj-cs.1806
    An implicational base is knowledge extracted from a formal context. The implicational base of a formal context consists of attribute implications which are sound, complete, and non-redundant regarding to the formal context. Non-redundant means that each attribute implication in the implication base cannot be inferred from the others. However, sometimes some attribute implications in the implication base can be inferred from the others together with a prior knowledge. Regarding knowledge discovery, such attribute implications should be not considered as new knowledge and ignored from the implicational base. In other words, such attribute implications are redundant based on prior knowledge. One sort of prior knowledge is a set of constraints that restricts some attributes in data. In formal context, constraints restrict some attributes of objects in the formal context. This article proposes a method to generate non-redundant implication base of a formal context with some constraints which restricting the formal context. In this case, non-redundant implicational base means that the implicational base does not contain all attribute implications which can be inferred from the others together with information of the constraints. This article also proposes a formulation to check the redundant attribute implications and encoding the problem into satisfiability (SAT) problem such that the problem can be solved by SAT Solver, a software which can solve a SAT problem. After implementation, an experiment shows that the proposed method is able to check the redundant attribute implication and generates a non-redundant implicational base of formal context with constraints.
  2. Ahmad A, Little M, Piernas C, Jebb S
    Arch Dis Child, 2022 Jul 18;107(10):896-901.
    PMID: 35851294 DOI: 10.1136/archdischild-2021-323493
    OBJECTIVES: To describe trends in reported weight loss attempts among school-aged children and to investigate its sociodemographic determinants.

    DESIGN: We analysed data of children who participated in the Health Survey for England from 1997 to 2016 (n=34 235). This repeated cross-sectional survey reported weight loss attempts and sociodemographic characteristics. Body weight and height were measured by trained interviewers, and body mass index for age z-score was calculated. Multivariable logistic regression was used to investigate the sociodemographic determinants.

    SETTING: England.

    PARTICIPANTS: Children (8-17 years).

    MAIN OUTCOME MEASURES: Weight loss attempts by year, age group, gender, BMI for age z-score, ethnicity and household income.

    RESULTS: The prevalence of reported weight loss attempts increased significantly from 21.4% (1997-1998) to 26.5% (2015-2016). The increase was significant for boys, older children, Asian children, children from lower income households and in all categories of BMI for age z-score. Significant predictors of weight loss attempts included having overweight (8-12 years old, OR 4.01 (%CI 3.47 to 4.64); 13-17 years old, OR 1.96 (%CI 1.58 to 2.42)) or obesity (8-12 years old, OR 13.57 (%CI 11.94 to 15.43); 13-17 years old, OR 4.72 (%CI 3.94 to 5.66)) as well as being older, girls, from ethnic minority groups or low household income.

    CONCLUSION: The prevalence of reported weight loss attempts among children is increasing at a faster rate than the rise in excess weight and includes an increasing proportion of children with a 'healthy' weight. The increase in the prevalence of reported weight loss attempts among children is greatest among subgroups with lower baseline prevalence.

  3. Kheirollahpour MM, Danaee MM, Merican AFAF, Shariff AAAA
    ScientificWorldJournal, 2020;2020:4194293.
    PMID: 32508538 DOI: 10.1155/2020/4194293
    The importance of eating behavior risk factors in the primary prevention of obesity has been established. Researchers mostly use the linear model to determine associations among these risk factors. However, in reality, the presence of nonlinearity among these factors causes a bias in the prediction models. The aim of this study was to explore the potential of a hybrid model to predict the eating behaviors. The hybrid model of structural equation modelling (SEM) and artificial neural networks (ANN) was applied to evaluate the prediction model. The SEM analysis was used to check the relationship of the emotional eating scale (EES), body shape concern (BSC), and body appreciation scale (BAS) and their effect on different categories of eating behavior patterns (EBP). In the second step, the input and output required for ANN analysis were obtained from SEM analysis and were applied in the neural network model. 340 university students participated in this study. The hybrid model (SEM-ANN) was conducted using multilayer perceptron (MLP) with feed-forward network topology. Moreover, Levenberg-Marquardt, which is a supervised learning model, was applied as a learning method for MLP training. The tangent/sigmoid function was used for the input layer, while the linear function was applied for the output layer. The coefficient of determination (R2) and mean square error (MSE) were calculated. Using the hybrid model, the optimal network happened at MLP 3-17-8. It was proved that the hybrid model was superior to SEM methods because the R2 of the model was increased by 27%, while the MSE was decreased by 9.6%. Moreover, it was found that BSC, BAS, and EES significantly affected healthy and unhealthy eating behavior patterns. Thus, a hybrid approach could be suggested as a significant methodological contribution from a machine learning standpoint, and it can be implemented as software to predict models with the highest accuracy.
  4. Musa H, Hafiz Kasim F, Nagoor Gunny AA, Gopinath SCB, Azmier Ahmad M
    J Basic Microbiol, 2019 Jan;59(1):87-100.
    PMID: 30270443 DOI: 10.1002/jobm.201800382
    An approach was made to enhance the halophilic lipase secretion by a newly isolated moderate halophilic Marinobacter litoralis SW-45, through the statistical optimization of Plackett-Burman (PB) experimental design and the Face Centered Central Composite Design (FCCCD). Initially, PB statistical design was used to screen the medium components and process parameters, while the One-factor-at-a-time technique was availed to find the optimum level of significant parameters. It was found that MgSO4  · 7H2 O, NaCl, agitation speed, FeSO4  · 7H2 O, yeast extract and KCl positively influence the halophilic lipase production, whereas temperature, carbon source (maltose), inducer (olive oil), inoculum size, and casein-peptone had a negative effect on enzyme production. The optimum level of halophilic lipase production was obtained at 3.0 g L-1 maltose, 1% (v/v) olive oil, 30 °C growth temperature and 4% inoculum volume (v/v). Further optimization by FCCCD was revealed 1.7 folds improvement in the halophilic lipase production from 0.603 U ml-1 to 1.0307 U ml-1 . Functional and biochemical characterizations displayed that the lipase was significantly active and stable in the pH ranges of 7.0-9.5, temperature (30-50 °C), and NaCl concentration (0-21%). The lipase was maximally active at pH 8.0, 12% (w/v) NaCl, and 50 °C temperature. Besides, M. litoralis SW-45 lipase was found to possess the promising industrial potential to be utilized as a biocatalyst for the esterification.
  5. Oglat AA, Matjafri MZ, Suardi N, Oqlat MA, Abdelrahman MA, Oqlat AA
    J Med Ultrasound, 2018 03 28;26(1):3-13.
    PMID: 30065507 DOI: 10.4103/JMU.JMU_11_17
    Medical Doppler ultrasound is usually utilized in the clinical adjusting to evaluate and estimate blood flow in both the major (large) and the minor (tiny) vessels of the body. The normal and abnormal sign waveforms can be shown by spectral Doppler technique. The sign waveform is individual to each vessel. Thus, it is significant for the operator and the clinicians to understand the normal and abnormal diagnostic in a spectral Doppler show. The aim of this review is to explain the physical principles behind the medical Doppler ultrasound, also, to use some of the mathematical formulas utilized in the medical Doppler ultrasound examination. Furthermore, we discussed the color and spectral flow model of Doppler ultrasound. Finally, we explained spectral Doppler sign waveforms to show both the normal and abnormal signs waveforms that are individual to the common carotid artery, because these signs are important for both the radiologist and sonographer to perceive both the normal and abnormal in a spectral Doppler show.
  6. Oglat AA, Matjafri MZ, Suardi N, Abdelrahman MA, Oqlat MA, Oqlat AA
    J Med Ultrasound, 2018 09 14;26(3):134-142.
    PMID: 30283199 DOI: 10.4103/JMU.JMU_7_18
    Background: To examine the blood flow and detection of the issues related to it by medical ultrasound, it is extremely important to have suitable blood mimicking fluid (BMF) to be used in vitro and to have a movable or portable Doppler flow phantom to use it as a standardizing tool. As known, the main drawbacks of the currently commercial BMF used in the research studies are high in cost and the long time needed for preparation, which is at least 5-7 h. Moreover, there are only two common scatter particles using in BMF as suspension materials such as nylon (Orgasol) and polystyrene. Thus, we need to prepare BMF with both a new mixture fluid and new scatter particle to be as a reflecting factor of ultrasonic waves, for evaluating the speed of sound of the blood flow in the same method like in the research study of ultrasound with relatively low-cost and less consuming time of preparation. However, both the acoustical and physical features of the Doppler flow phantom components (BMF and tissue mimicking material) must correspond the features of the human tissues to make the examination significance. In addition, the BMF must also represent the hemodynamic features of real human blood.

    Methods: In this experiment, a new adequate ternary mixture liquid for preparation of BMF applied and suspended with a new scatter particle material, this scatter particle material called poly (4-methylstyrene), it used to be adequate with the mixture density and for saving neutrally buoyant. This BMF was prepared for use in the test objects or Doppler flow phantom. The poly (4-methylstyrene) particles were applied for suspension in a mixture liquid or fluid based on three items, which were distilled water, propylene glycol (PG), and polyethylene glycol (PEG) (200 Mw). The diameter of poly (4-methylstyrene) particles is 3-8 μm, which determined by specific sieve in a unit of μm, and the density is 1.040 g/ml.

    Results: Speed of sound, viscosity, density, Backscatter power and attenuation features of mixture fluid or liquid which used for preparing a BMF were measured, discussed, and agreed with draft International Electrotechnical Commission values.

    Conclusions: There are three various types of ternary items of mixture fluid (water, PG, and PEG [200 Mw]), and a new type of scatter particle material poly (4-methylstyrene) was utilized for preparing the BMF. The scatter particles and mixture fluid prepared and measured at a temperature that simulates the body temperature 37°C. Moreover, one of the advantages of this new blood that is being cheaper than the commercially available BMF products because the PG and the polyethylene glycol (200 Mw) are much cheaper and more available than glycerol and the Dextran that used usually. In addition, new BMF needs less time for preparation compared to the commercial one.

  7. Oglat AA, Suardi N, Matjafri MZ, Oqlat MA, Abdelrahman MA, Oqlat AA
    J Med Ultrasound, 2018;26(2):68-76.
    PMID: 30065522 DOI: 10.4103/JMU.JMU_1_17
    Doppler ultrasound imaging system description and calibration need blood-mimicking fluids (BMFs) for the test target of medical ultrasound diagnostic tools, with known interior features and acoustic and physical properties of this fluid (BMF). Physical and acoustical properties determined in the International Electrotechnical Commission (IEC) standard are specified as constant values, the materials used in the BMF preparation should have values similar to the IEC standard values. However, BMF is ready-made commercially from a field of medical usage, which may not be appropriate in the layout of ultrasound system or for an estimate of novel imaging mechanism. It is often eligible to have the capability to make sound properties and mimic blood arrangement for specific applications. In this review, sufficient BMF materials, liquids, and measures are described which have been generated by utilizing diverse operation mechanism and materials that have sculptured a range of biological systems.
  8. Jawi ZM, Deros BM, Rashid AAA, Isa MHM, Awang A
    Sultan Qaboos Univ Med J, 2017 Aug;17(3):e277-e285.
    PMID: 29062549 DOI: 10.18295/squmj.2017.17.03.004
    This review article aimed to analyse existing literature regarding the roles and performance of professional driving instructors (PDIs) in novice driver education (DE). A systematic classification scheme was adopted to analyse identified articles to determine the study context of PDIs in novice DE, the competency level of PDIs in relation to experienced and learner drivers and the contributions of PDIs to the novice driver learning process. A total of 14 original research articles were identified, with no systematic reviews or meta-analyses available. Overall, all of the articles were found to be inadequate in providing an in-depth understanding of the roles and performance of PDIs in novice DE. There is an urgent need to improve current understanding of the roles of PDIs in novice DE and to work towards an internationally recognised PDI management approach.
  9. Khan MU, Shah S, Ahmad A, Fatokun O
    BMC Public Health, 2014;14:1281.
    PMID: 25510239 DOI: 10.1186/1471-2458-14-1281
    BACKGROUND: With the increase in prevalence of Middle East Respiratory Syndrome (MERS), healthcare workers (HCWs) are at risk of acquiring and subsequently transmitting this lethal virus. In view of this, HCWs were evaluated for their knowledge of and attitude towards MERS in Saudi Arabia.
    METHODS: A cross sectional study was performed in two hospitals of Qassim region in Saudi Arabia. A total of 280 healthcare workers were selected to participate in this study. Knowledge and attitude were assessed by using self-administered and pretested questionnaire. Descriptive statistics were carried out to express participants' demographic information, mean knowledge score and mean attitude score of HCWs. Inferential statistics (Mann-Whitney U test and Kruskal Wallis tests, p < 0.05) were used to examine differences between study variables. Chi squares tests were used to assess the association between study variables and attitude questions. Spearman's rho correlation was used to identify the association between the knowledge, attitude scores.
    RESULT: Participants demonstrated good knowledge and positive attitude towards MERS. The mean scores of knowledge and attitude were 9.45 ± 1.69 (based on 13 knowledge questions) and 1.82 ± 0.72 (based on 7 attitude questions). The correlation between knowledge and attitude was significant (correlation coefficient: 0.12; P <0.001). HCWs were less educated about the management (42.4%), source (66%) and consequences of MERS (67.3%), while a majority of them were well aware of the hallmark symptoms (96%), precautionary measures (96%) and hygiene issues (94%). Although the majority of respondents showed positive attitude towards the use of protective measures (1.52 ± 0.84), their attitude was negative towards their active participation in infection control program (2.03 ± 0.97). Gender and experience were significantly associated with knowledge and attitude (P < 0.05).
    CONCLUSIONS: The findings of this study showed that healthcare workers in Qassim region of Saudi Arabia have good knowledge and positive attitude towards MERS. Yet there are areas where low knowledge and negative attitude of HCWs was observed. However, studies are required to assess the knowledge and attitude of HCWs at national level so that effective interventions could be designed as surveillance and infection control measures are critical to global public health.
  10. Ahmad A, Ramasamy K, Majeed AB, Mani V
    Pharm Biol, 2015 May;53(5):758-66.
    PMID: 25756802 DOI: 10.3109/13880209.2014.942791
    Soybean and its fermented products are the most common source of isoflavones in human food.
  11. Rabbani G, Khan MJ, Ahmad A, Maskat MY, Khan RH
    Colloids Surf B Biointerfaces, 2014 Nov 1;123:96-105.
    PMID: 25260221 DOI: 10.1016/j.colsurfb.2014.08.035
    The primary objective of this study is to explore the interaction of β-galactosidase with copper oxide nanoparticles (CuO NPs). Steady-state absorption, fluorescence and circular dichroism (CD) spectroscopic techniques have been employed to unveil the conformational changes of β-galactosidase induced by the binding of CuO NPs. Temperature dependent fluorescence quenching results indicates a static quenching mechanism in the present case. The binding thermodynamic parameters delineate the predominant role of H-bonding and van der Waals forces between β-galactosidase and CuO NPs binding process. The binding was studied by isothermal titration calorimetry (ITC) and the result revealed that the complexation is enthalpy driven, the ΔH°<0, ΔS°<0 indicates the formation of hydrogen bonds between β-galactosidase and CuO NPs occurs. Disruption of the native conformation of the protein upon binding with CuO NPs is reflected through a reduced functionality (in terms of hydrolase activity) of the protein CuO NPs conjugate system in comparison to the native protein and CuO NPs exhibited a competitive mode of inhibition. This also supports the general belief that H-bond formation occurs with NPs is associated with a lesser extent of modification in the native structure. Morphological features and size distributions were investigated using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Additionally the considerable increase in the Rh following the addition of CuO NPs accounts for the unfolding of β-galactosidase. Chemical and thermal unfolding of β-galactosidase, when carried out in the presence of CuO NPs, also indicated a small perturbation in the protein structure. These alterations in functional activity of nanoparticle bound β-galactosidase which will have important consequences should be taken into consideration while using nanoparticles for diagnostic and therapeutic purposes.
  12. Ahmad A, Dada AC, Usup G, Heng LY
    Mar Pollut Bull, 2014 May 15;82(1-2):26-38.
    PMID: 24725825 DOI: 10.1016/j.marpolbul.2014.03.028
    Median enterococci counts of beach water samples gradually increased at statistically significant levels (χ2: 26.53, df: 4; p<0.0001) with increasing proximity to river influx. The difference in proportion of antibiotic resistant enterococci in beach water and river water samples was statistically significant (p<0.05) for the tested antibiotics with river isolates generally presenting higher resistance frequencies. Virulence genes cyl, esp, gelE and asa were detected at varying frequencies (7.32%, 21.95%, 100% and 63.41% respectively) among river isolates. On the other hand, the prevalence of these genes was lower (0%, 20%, 67.27% and 41.82% respectively) among beach water isolates. Multi-Locus-Sequence-Typing analysis of Enterococcus faecalis presented four sequence types (ST) one of which shared six out of seven tested loci with ST6, a member of the clonal complex of multi-drug resistant strains associated with hospital outbreaks.
  13. Jafarzade M, Yahya NA, Shayesteh F, Usup G, Ahmad A
    J Microbiol, 2013 Jun;51(3):373-9.
    PMID: 23812818 DOI: 10.1007/s12275-013-2440-2
    This study was undertaken to investigate the influence of culture conditions and medium components on production of antibacterial compounds by Serratia sp. WPRA3 (JX020764) which was isolated from marine water of Port Dickson, Malaysia. Biochemical, morphological, and molecular characteristics suggested that the isolate is a new candidate of the Serratia sp. The isolate showed strong antimicrobial activity against fungi, Gram-negative and Gram-positive bacteria. This bacterium exhibited optimum antibacterial compounds production at 28°C, pH 7 and 200 rev/min aeration during 72 h of incubation period. Highest antibacterial activity was obtained when sodium chloride (2%), yeast extract (0.5%), and glucose concentration (0.75%) were used as salt, nitrogen, and carbon sources respectively. Different active fractions were obtained by Thin-Layer Chromatography (TLC) and Flash Column Chromatography (FCC) from ethyl acetate crude extracts namely OCE and RCE in different culture conditions, OCE (pH 5, 200 rev/min) and RCE (pH 7/without aeration). In conclusion, the results suggested different culture conditions have a significant impact on the types of secondary metabolites produced by the bacterium.
  14. Ahmad A, Hamid R, Dada AC, Usup G
    Probiotics Antimicrob Proteins, 2013 Sep;5(3):165-75.
    PMID: 26782985 DOI: 10.1007/s12602-013-9140-4
    Bacteriocin-producing Pseudomonas putida strain FStm2 isolated from shark showed broad range of antibacterial activity against all pathogens tested except Bacillus subtilis ATCC11774, MRSA N32064, Proteus mirabilis ATCC12453, Enterococcus faecalis ATCC14506, Salmonella typhimurium ATCC51312, Salmonella mutan ATCC25175, and Aeromonas hydrophila Wbf314. Of the three growth media tested in this study, TSB was observed to support the bacteriocin activity the most. While the highest bacteriocin activity was observed for media supplemented with 1 % NaCl, there was an observed reduction in bacteriocin activity with increasing salt concentration. Although the least bacteriocin activity was observed for marine broth, addition of increasing amounts of tryptone, glucose, or yeast extract increased bacteriocin activity. This was, however, contrary to the effect observed when MgSO4 and MnSO4 were added as supplements. In the presence of α-amylase, lipase, DNase, and RNase, a positive effect on bacteriocin production was observed. Proteinase K strongly inhibited bacteriocin production. Furthermore, the bacteriocins produced were heat stable within the temperature range of 30-70 °C. Bacteriocin activity also was not affected within a wide pH range of 3-9. Exposure to detergents did not inhibit the activity of the bacteriocin at the concentrations tested. Instead, a positive effect on the relative activity of produced bacteriocin was observed as sodium dodecyl sulfate (SDS), EDTA, and Tween 20 at 1 % concentration all improved bacteriocin activity when the cell-free supernatant was tested against Serratia marcescens ATCC 13880. The bacteriocin was purified by ammonium sulfate precipitation and gel filtration on a Superdex-200 column. SDS-PAGE analysis of the partially purified bacteriocin revealed an apparent molecular weight of ~32 kDa.
  15. Junaidi MU, Leo CP, Kamal SN, Ahmad AL
    Water Sci Technol, 2013;67(9):2102-9.
    PMID: 23656955 DOI: 10.2166/wst.2013.098
    Although ultrafiltration (UF) membranes are applicable in wastewater and water treatment, most UF membranes are hydrophobic and susceptible to severe fouling by natural organic matter. In this work, polysulfone (PSf) membrane was blended with silicaluminophosphate (SAPO) nanoparticles, SAPO-34, to study the effect of SAPO-34 incorporation in humic acid (HA) fouling mitigation. The casting solution was prepared by blending 5-20 wt% of SAPO-34 nanoparticles into the mixture of PSf, 1-methyl-2-pyrrolidinone and polyvinyl alcohol at 75 °C. All membrane samples were then prepared using the phase inversion method. Blending SAPO-34 zeolite into PSf membranes caused augmentation in surface hydrophilicity and pore size, leading to higher water permeation. In the HA filtration test, mixed matrix membranes (MMMs) with SAPO-34 zeolite showed reduced HA fouling initiated from pore blocking. The MMM with 20 wt% SAPO-34 loading exhibited the highest increment of water permeation (83%) and maintained about 75% of permeate flux after 2.5 h. However, the SAPO-34 fillers agglomerated in the PSf matrix and induced macrovoid formation on the membrane surface when excessive zeolite was added.
  16. Low SC, Shaimi R, Thandaithabany Y, Lim JK, Ahmad AL, Ismail A
    Colloids Surf B Biointerfaces, 2013 Oct 1;110:248-53.
    PMID: 23732801 DOI: 10.1016/j.colsurfb.2013.05.001
    Protein adsorption onto membrane surfaces is important in fields related to separation science and biomedical research. This study explored the molecular interactions between protein, bovine serum albumin (BSA), and nitrocellulose films (NC) using electrokinetic phenomena and the effects of these interactions on the streaming potential measurements for different membrane pore morphologies and pH conditions. The data were used to calculate the streaming ratios of membranes-to-proteins and to compare these values to the electrostatic or hydrophobic attachment of the protein molecules onto the NC membranes. The results showed that different pH and membrane pore morphologies contributes to different protein adsorption mechanisms. The protein adsorption was significantly reduced under conditions where the membrane and protein have like-charges due to electrostatic repulsion. At the isoelectric point (IEP) of the protein, the repulsion between the BSA and the NC membrane was at the lowest; thus, the BSA could be easily attached onto the membrane/solution interface. In this case, the protein was considered to be in a compact layer without intermolecular protein repulsions.
  17. Dada AC, Ahmad A, Usup G, Heng LY
    Environ Monit Assess, 2013 Feb;185(2):1583-99.
    PMID: 22592782 DOI: 10.1007/s10661-012-2653-6
    We report the first study on the occurrence of antibiotic-resistant enterococci in coastal bathing waters in Malaysia. One hundred and sixty-five enterococci isolates recovered from two popular recreational beaches in Malaysia were speciated and screened for antibiotic resistance to a total of eight antibiotics. Prevalence of Enterococcus faecalis and Enterococcus faecium was highest in both beaches. E. faecalis/E. faecium ratio was 0.384:1 and 0.375:1, respectively, for isolates from Port Dickson (PD) and Bagan Lalang (BL). Analysis of Fisher's exact test showed that association of prevalence of E. faecalis and E. faecium with considered locations was not statistically significant (p < 0.05). Chi-square test revealed significant differences (χ(2) = 82.630, df = 20, p < 0.001) in the frequency of occurrence of enterococci isolates from the considered sites. Resistance was highest to nalidixic acid (94.84 %) and least for chloramphenicol (8.38 %). One-way ANOVA using Tukey-Kramer multiple comparison test showed that resistance to ampicillin was higher in PD beach isolates than BL isolates and the difference was extremely statistically significant (p < 0.0001). Frequency of occurrence of multiple antibiotic resistance (MAR) isolates were higher for PD beach water (64.29 %) as compared to BL beach water (13.51 %), while MAR indices ranged between 0.198 and 0.48. The results suggest that samples from Port Dickson may contain MAR bacteria and that this could be due to high-risk faecal contamination from sewage discharge pipes that drain into the sea water.
  18. Syafalni, Lim HK, Ismail N, Abustan I, Murshed MF, Ahmad A
    J Environ Manage, 2012 Dec 15;112:353-9.
    PMID: 22964042 DOI: 10.1016/j.jenvman.2012.08.001
    In this research, the capability of lateritic soil used as coagulant for the treatment of stabilized leachate from the Penang-Malaysia Landfill Site was investigated. The evaluation of lateritic soil coagulant in comparison with commercialized chemical coagulants, such as alum, was performed using conventional jar test experiments. The optimum pH and coagulant dosage were identified for the lateritic soil coagulant and the comparative alum coagulant. It was found that the application of lateritic soil coagulant was quite efficient in the removal of COD, color and ammoniacal-nitrogen content from the landfill leachate. The optimal pH value was 2.0, while 14 g/L of lateritic soil coagulant was sufficient in removing 65.7% COD, 81.8% color and 41.2% ammoniacal-nitrogen. Conversely, the optimal pH and coagulant dosage for the alum were pH 4.8 and 10 g/L respectively, where 85.4% COD, 96.4% color and 47.6% ammoniacal-nitrogen were removed from the same leachate sample. Additionally, the Sludge Volume Index (SVI) ratio of alum and lateritic soil coagulant was 53:1, which indicated that less sludge was produced and was an environmentally friendly product. Therefore, lateritic soil coagulant can be considered a viable alternative in the treatment of landfill leachate.
  19. Ahmad A, Othman I, Md Zain AZ, Chowdhury EH
    Curr Drug Deliv, 2015;12(2):210-22.
    PMID: 22452407
    Diabetes mellitus is a chronic disease accompanied by a multitude of problems worldwide with subcutaneously administered insulin being the most common therapy currently. Controlledrelease insulin is assumed to be of high importance for long-term glycaemic control by reducing the number of daily injections. Long-acting insulin also mimics the basal insulin levels in normal individuals that may be lacking in diabetic patients. Nanoparticles of carbonate apatite as established for efficient intracellular transport of DNA and siRNA have the potential to be used for sustained release of insulin as responsive nano-carriers. The flexibility in the synthesis of the particles over a wide range of pHs with eventual adjustment of pH-dependent particle dissolution and the manageable variability of particle-integrity by incorporating selective ions into the apatite structure are the promising features that could help in the development of sustained release formulations for insulin. In particular strontium-incorporated carbonate apatite particles were formulated and compared with those of unsubstituted apatite in the context of insulin binding and subsequent release kinetics in DMEM, simulated buffer and finally human blood over a period of 20 hours. Clearly, the former demonstated to have a stronger electrostatic affinity towards the acidic insulin molecules and facilitate to some extent sustained release of insulin by preventing the initial burst effect at physiological pH in comparison with the latter. Thus, our findings suggest that optimization of the carbonate apatite particle composition and structure would serve to design an ideal insulin nano-carrier with a controlled release profile.
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