A stability-indicating HPLC-UV method for the simultaneous determination of sildenafil citrate and dapoxetine hydrochloride in solution and tablet was developed. The mobile phase was comprised of acetonitrile and 0.2M ammonium acetate buffer. The analyte was eluted at 3.392min and 7.255min for sildenafil citrate and dapoxetine HCl respectively using gradient system at a flow rate of 1.5mL/min. The theoretical plates count was>2000, tailing factor
Drug nanosuspensions have gained tremendous attraction as a platform in drug delivery. In the present work, a nanosuspension was prepared by a wet milling approach in order to increase saturation solubility and dissolution of the water insoluble drug, hydrocortisone. Size of the generated particeles was 290 nm ± 9 nm having a zeta potential of -1.9 mV ± 0.6 mV. Nanosized particles were found to have a rod shape with a narrow particle size distribution (PDI =0.17). Results of differential scanning calorimetry and X-ray diffraction analyses revealed minor modifications of crystallinity of hydrocortisone following the milling process. Solubility of hydrocortisone was enhanced by nanonization to 875µg/ml ±2.5, an almost 2.9-fold compared to the raw hydrocortisone. Moreover, the nanosuspension formulation substabtially enhanced the dissolution rate of hydrocortisone where >97% of the hydrocortisone was dissolved within 10 minutes opposed to 22.3% for the raw 50% for the raw hydrocortisone and the commercial tablet, respectively. The bioavailability study resulted in AUC 0-9h for HC nanosuspensions (31.50±2.50), which is significantly (p<0.05) higher compared to the AUC 0-9h (14.85±3.25) resulted for HC solution. The nanosuspension was physically stable at room temperature for 24 months.
Microbial keratitis is one of the most challenging complications of contact lens (CL) wear. Proper CL practice plays an important role to reduce the risk for contact lens related microbial keratitis (CLRMK). Methods: This multi-centre case-control study was conducted from January 2008 until June 2009 to determine the risk factors associated with CLRMK. Cases were defined as respondents who were treated for CLRMK, whilst controls were respondents who were contact lens wearers without microbial keratitis. Ninety four cases were compared to 94 controls to determine the risk factors for
CLRMK. Results: The predictors for CLRMK were: Not washing hands with soap before handling CL (aOR 2.979, CI 1.020, 8.701 p=0.046), not performing rubbing technique whilst cleaning the CL (aOR 3.006, CI 1.198, 7.538 p=0.019) and, not cleaning the lens case with multipurpose solution daily (aOR 3.242 CI 1.463, 7.186 p=0.004). Sleeping overnight with the CL in the eye (aOR 2.864, CI 0.978, 8.386 p=0.049) and overall non-compliance with lens care procedures (aOR 2.590, CI 1.003, 6.689 p=0.049) contributed significantly to CLRMK. Conclusion: Health education and promotion in contact lens care are important and should be conducted by eye care practitioners to reduce the occurrence of CLRMK.
This paper presents on ionic conductivity of MG30-PEMA blend solid polymer electrolytes (SPEs) prepared by solution cast technique. The analysis has shown that conductivity increases with the increasing salt composition. It is observed via x-ray diffraction analysis that the crystallinity of the sample decreased with the amount of salt composition as expected. It is also observed that the dielectric value increases with increasing amount of LiCF3SO3 in the sample. Surface morphology revealed that ion aggregation occurred after optimum conductivity which has lowered the conductivity.
Many studies have been carried out using different metaheuristic algorithms on optimisation problems in various fields like engineering design, economics and routes planning. In the real world, resources and time are scarce. Thus the goals of optimisation algorithms are to optimise these available resources. Different metaheuristic algorithms are available. The firefly algorithm is one of the recent metaheuristic algorithms that is used in many applications; it is also modified and hybridised to improve its performance. In this paper, we compare the Standard Firefly Algorithm, the Elitist Firefly Algorithm, also called the Modified Firefly Algorithm with the Chaotic Firefly Algorithm, which embeds chaos maps in the Standard Firefly Algorithm. The Modified Firefly Algorithm differs from the Standard Firefly Algorithm in such a way that the global optimum solution at a particular iteration will not move randomly but in a direction that is chosen from randomly generated directions that can improve its performance. If none of these directions improves its performance, then the algorithm will not be updated. On the other hand, the Chaotic Firefly Algorithm tunes the parameters of the algorithms for the purpose of increasing the global search mobility i.e. to improve the attractiveness of fireflies. In our study, we found that the Chaotic Firefly Algorithms using three different chaotic maps do not perform as well as the Modified Firefly Algorithms; however, at least one or two of the Chaotic Firefly Algorithms outperform the Standard Firefly Algorithm under the given accuracy and efficiency tests.
Dye-sensitized solar cell (DSSC) is the third generation of thin film solar cell. In this work, carrot fruit dye was prepared and used in DSSC as a sensitizer. TiO2–ZrO2 fine binary oxide was mechanochemically prepared and made paste. TiO2–ZrO2 paste (colloidal) was deposited onto FTO/glass in two ways, i.e. as single and double coatings by rolling method. It was immersed in the carrot solution to get dyed cell. The dyed TiO2-ZrO2-FTO/glass cell was offset with the FTO/glass cell coated with adhesive carbon paste. Photovoltaic properties of prepared TiO2–ZrO2 DSSC cell were measured. Results showed that the efficiency of double coating cell was greater than that of the single coating cell. According to the fill factor from the experiments, both the DSSC cells were acceptable for industrial requirement. Hence, it can be concluded that the results obtained were acceptable in the use of cost-effective and eco-favourable dye-sensitized solar cell.
In this paper, a mathematical model is developed based on mass and momentum balance for carbon dioxide absorption into aqueous ammonia solution. The model is simplified based on the assumption that the CO2 absorption into aqueous ammonia is a pseudo-first-order reaction. Laplace transform method is applied in order to solve the partial differential model equation. Finally, the CO2 molar flux is expressed as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area. Variation of CO2 molar flux with partial pressure of CO2 and temperature is discussed and a comparison is performed with experimental data from literature. Variation of CO2 molar flux is also shown with gas-liquid contact area. The calculated flux from the model follows the same trend as that of the experimental data reported in literature and the accuracy is within the accepted limit. The mathematical model is very helpful to predict the CO2 molar flux as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area.
Oil blending has been recognized as one of the most potent solution in producing vegetable oils with good storage stabilities and optimum fatty acids compositions. This study was conducted to identify the best oil blends in terms of physicochemical properties between canola, olive and palm olein oil. Canola and olive oils were blended at different ratios of 80:20, 60:40, 50:50, 40:60, and 20:80. Palm olein is stable against rancidity and oxidation thus the above blends were mixed with 20% palm olein. The 80:20 canola: olive blend shows the best properties after being mixed with 20% palm olein compared to other blends. It passed the cold stability test and has significantly the lowest cloud point of 6.0oC (p
Introduction: Knowledge, attitude as well as adoption of pharmacogenomics in clinical practice among the pharmacists and physicians in Malaysia have not been reported. This cross-sectional study explores various facets of the two professions as related to pharmacogenomics to determine the need and preferred method to improve education among them. This study also aims to identify the current state of pharmacogenomics practice in Malaysia to help identify barrier and solution to reap advantages from pharmacogenomics practices. Methods: A questionnaire consisting of 38 questions in five parts was adopted and validated. It explores the respondents’ characteristics, attitude, knowledge, adoption and education. It was distributed online to 1500 pharmacists and physicians over five months. Results: Pharmacists differed from the physicians in terms of attitude, knowledge, adoption and education. Overall, adoption rate of pharmacogenomics was found to be low but its anticipation for future adoption is high, and benefits were reported by healthcare professionals who have used the test in a clinical setting. Majority of respondents had poor to fair knowledge and nearly half have had no prior formal teaching on pharmacogenomics. Interest in the education is very high, and most of them preferred to learn pharmacogenomics via continuous professional education programs. Conclusion: Pharmacogenomics is a field that promises many benefits, but to reap these benefits require its implementation in clinical setting. Pharmacists and physicians need to be equipped with adequate knowledge and positive attitude towards pharmacogenomics.
This paper presents the solution to a calculation of the pH of a very dilute solution of a weak acid, taking into account the effect of the hydroxonium ions generated from the ionization of the acid on the ionization of water, also a very weak acid. To be solved successfully, this calculation involves the concepts of conservation of charge, pH, equilibria and the application of the general solution to a cubic equation. Such an exercise requires the application of skills in algebra, and can provide a core of understanding that can prepare advanced students for many different sorts of calculations that represent real-life problems in the chemical sciences. A programme is presented in C++ which enables the work of students to be individualized so that each student in a class can work through a slightly different pH calculation, in such a way that a class supervisor can quickly check each student’s result for accuracy.This exercise is presented as a potential means of enabling students to undertake and master similar types of calculations involving the application of complex algebra to problems related to equilibria and solution dynamics.
The effect of ribose-induced Maillard reaction on the physical and mechanical properties of gelatin films was investigated. Bovine gelatin solution (5 g/100 mL) containing glycerol and sorbitol (1:1) was mixed with 20% (R20), 40% ribose (R40), or 40% sucrose (S40) (weight % is based on gelatin dry weight) followed by heating (90ºC, 2 h) and oven drying to produce dried gelatin films. R20 and R40 films were brownish in color with lower light transparency, while CF (control film; without sugars) and S40 were colorless and had higher transparency. Tensile strength and Young Modulus values of the films were in the order; CF > R20 > R40 > S40, while elongation at break was in the order; R40 > S40 > R20 > CF. Water solubility and swelling percentages of the films were in the order; CF > S40 > R20 > R40, indicating the occurrence of insoluble “Maillard complexes” within R20 and R40 films. R20 and R40 films showed maximum light absorption at wavelength of 200 − 350 nm, whilst S40 and CF showed maximum absorbance at 200 − 250 nm. The addition of ribose yielded gelatin films with increased protection against UV light, even though the presence of sugars might had disrupted the inter connection of junction zones and decrease in mechanical properties. Occurrence of the Maillard reaction within R20 and R40 films could be the main reason for differences in physical and mechanical properties of films containing ribose that were formed from heated film-forming solutions.
This study is carried out to determine the physical properties of green pepper berries and to
improve the existing retting technique in white pepper production using the Viscozyme and
Celluclast as the enzymes. Effects of blanched and non-blanched pepper berries, acidic solution
and non-acidic solution, and different temperature of 28, 35, 42, and 49°C are determined to
obtain the optimum conditions for enzymatic retting. The physical properties of green pepper
berries such as dimension (5.21 mm), weight (0.11 g per berry), true density (1319.33 kg/m3),
bulk density (596.9 kg/m3), sphericity (0.976), angle of repose (6.87°) and flow ability with
funnel flow time of 5.27 seconds were determined. The enzymatic retting in 42oC can fully
soften the pericarp of pepper berries from 15 days to 7 days. The enzymatic decortication has
the efficiency in acidic solution (pH 4) and temperature of 42°C with non-blanched pepper
berries. The enzymatic retting reached constant fracture force (20.98N) at the ninth soaking
days while the non-enzymatic retting reached constant fracture force (21.89N) at the fifteenth
soaking days.
Carbon-11 labeled radiotracers, such as 11C-acetate and
11C-palmitate are widely used in positron
emission tomography (PET) for noninvasive evaluation of myocardial metabolism under varied
physiological conditions.These tracers are attractive probes of tissue physiology, because they are
simply radiolabled versions of the native biochemical substrates. One of the major metabolites
generated by these tracers upon the administration is 11CO2 produced via the citric acid cycle. In
quantitative modeling of
11C-acetate and
11C-palmitate PET data, the fraction of blood
11C
radioactivity present as
11CO2 needs to be measured to obtain a correct radiotracer arterial
input function. Accordingly, the literature describes a method whereby the total blood
11C-activity
is counted in blood samples treated with base solution, while the fraction of
1 1CO2 is measured
after the blood is treated with acid followed by a 10 minutes gas-purge. However, a detailed
description of the experimental validation of this method was not provided. The goal of this study
was to test the reliability of a 10 minute gas purging method used to assay
11CO2 radioactivity in
blood
In the current research, osmotic dehydration of red pitaya (Hylocereus polyrhizusis) cubes using sucrose solution at mild temperature (35ºC) was investigated. Sucrose solution (40, 50 and 60% w/w) was employed for osmotic dehydration process. Responses of weight reduction (WR), solid gain (SG), water loss (WL), color (L*, a* and b*) and texture (hardness) were evaluated. It was found that sucrose concentration significantly (p < 0.05) affected the mass transfer terms during osmosis process. The results obtained revealed an increase in yellowness (b*), decrease in lightness (L*) and redness (a*) as the sucrose concentration increased. Furthermore, osmotically dehydrated samples were considerably softer than untreated samples. Increasing of sucrose concentration and dehydration time caused softer tissue of dehydrated product compared with the fresh red pitaya.
The Short Form Health Survey SF-36 is a well-known generic health-related quality of life measure that has widely been used worldwide. However, given the cultural, social and ethnic differences in some countries, it might not follow the intended structure of the instrument. Hence, this study aims to determine the psychometric properties of the Malay version of Short Form Health Survey (SF-12) among postpartum mothers. A cross-sectional study was conducted among 1-month postpartum mothers attending Obstetric and Gynecology clinic, Universiti Sains Malaysia Hospital, Kelantan, Malaysia. Reliability was estimated using internal consistency and the factor structure was extracted by performing confirmatory factor analysis using SPSS v. 20 and AMOS v. 20. A total of 108 women responded. The mean (SD) score for the Physical Component Summary (PCS) score and Mental Component Summary (MCS) score were 43.3 (7.08) and 42.4 (6.87) respectively. The Cronbach alpha for PCS-12 was 0.749 and MCS-12 was 0.701. Spearman correlations of individual items and the SF-12 component summary scores showed PF, RP, BP and GH items correlated higher with the PCS score, whereas the VT, SF, RE, and MH items correlated higher with the MCS score lending support to its good convergent validity. The confirmatory factor solution showed final model with two factors structure and six items each with acceptable factor loadings, satisfactory absolute and parsimonious fitness (RMSEA=0.1, x2/df=2.4). The psychometric tests of the Malay version of SF-12 generally showed acceptable validity and reliability among postpartum women.
Study site: Obstretic and gynecology Hospital Universiti Sains Malaysia (HUSM)
This study is an attempt to investigate the adsorption of petroleum hydrocarbon (toluene) from aqueous solutions using granular activated carbon (GAC) synthesized from oil palm shell (OPS) (referred as OPSbased GAC). This study involved a series of batch experiments to determine the adsorption equilibrium and kinetics. The batch experiments were conducted by shaking 200 mL toluene solution containing 0.4 g GAC (initial concentrations of 5, 15, 25 and 30 mg/L) at 180 rpm at 30°C. The OPS-based GAC achieved more than 80% toluene removal in all the experiments. The adsorption capacity of the OPSbased GAC estimated using Freundlich isotherm was 6.039 mg/g (L/mg)1/n. The adsorption kinetic study showed that the adsorption of toluene was of chemisorption as the experimental data fitted better to the pseudo-second-order kinetic model than the pseudo-first-order kinetic model.
The modelling of a three-dimensional (3-D) molten carbonate fuel cell (MCFC) was developed to study the effects of gas flow direction (co-flow and counter-flow) in anode and cathode on the generated power density by solving the mass and momentum conservation equations, electrochemical reaction and heat transfer. The simulation result of the co-flow temperature distribution was compared with the experimental data obtained from open literature. The molar fraction distribution of gases in the anode and cathode gas channels and temperature distribution across the cell were compared between two different flow directions. Furthermore, the performance of MCFC, which operates in the temperature range of 823 - 1023 K, was analysed by comparing the generated power density. The results showed that MCFC with co-flow attained higher power density compared to that of counter-flow at 873 K. However, at higher temperature of 1023 K, the generated power density was the same for both gas flow directions.
HCFCs, in addition to destroying the ozone layer, have been recognized as a contributing factor that increases global warming. It is widely used as working fluid in window air-conditioning system, where capillary tube serves as an expansion device. Literature reports have shown that no single refrigerant can solve the problem of ozone layer depletion and global warming. Refrigerant HC290/HC600a/HFC407C mixture, an eco-friendly refrigerant, has been recognized as an alternative to HCFC22. The objective of this study is to, for cost effectiveness, develop an empirical correlation to predict the refrigerant HC290/ HC600a/HFC407C mixture mass flow rate using statistical experimental design approach. A review of relevant literature shows that refrigerant’s mass flow rate depends on condensing temperature, degree of subcooling, inner diameter and length of capillary tube. The relationship between the mass flow rate and the four independent variables was established as an empirical mathematical correlation using central composite design (CCD), a response surface methodology (RSM). This empirical correlation was examined using analysis of variance (ANOVA) of 5% level of significance. The results of these analysis showed that the correlation fitted well with the experimental data yielding an average and standard deviation of 1.05% and 2.62%, respectively. The validity of the present correlation was further assessed by comparing it with published empirical correlation in literature and the result showed that the present correlation is consistent.
This study was conducted using crab shells as a biosorbent to remove Cu and Cd with different initial concentrations of 1, 5, 10, 15, and 20 mg/L in a biosorption treatment process. Crab shells were selected as biosorbents due to their abundance in the environment and ready availability as waste products from the market place. This study aimed to determine the ability of Scylla Serrata shells to remove Cu and Cd in an aqueous solution, as well as to provide a comparison of the removal rate between the two metals. The data were incorporated into hydrochemical software, PHREEQC, to investigate the chemical speciation distribution of each heavy metal. The shells of S. serrata were found to have a significant (p< 0.05) ability to remove Cu and Cd following the treatment. After six hours of treatment, the crab shells had removed 60 to 80% of both metals. However, the highest removal percentage was achieved for Cu with up to 94.7% removal rate in 5 mg/L initial Cu concentration, while 85.1% of Cd was removed in 1 mg/L initial solution, respectively. It can be concluded that the shells of S. serrata could remove Cu and Cd better with significant results (p
In the moving layer of particles with variable concentration, the shear estimation is not directly predictable and there is no existing clear mathematical or empirical formula to achieve this objective. This paper presents a developed approach to estimate the shear forces in a flow having suspended and moving layers of solid particles in liquid flow. The two-layer approach was taken whereby the flow consisting of one upper suspended layer of particles in the liquid, and the bottom layer was the moving bed of particles. In the present work, the method of finding the force acting on the pipe wall by the particles in the layer, termed as the ‘dry force’, was presented using a “pseudo hydrostatic pressure” method. To attain the equation for the dry force, a mathematical approach is taken with the assumptions that the flow is horizontal, two-phase pipe flow (solid in Newtonian liquid), incompressible and it is at steady-state. The analysis was conducted considering various particles densities, various concentrations in the suspended layer and different thicknesses of the moving bed. Changing the concentration in the suspended layer from 0.00001 up to 0.001 didn’t showed significant changes in the dry force evaluation. The dry friction force is increasing with increasing moving bed thickness. The developed mathematical model can be
applicable in solving for the shear force in horizontal solid liquid two-phase flows.