Malaysian Journal of Science

OPTIMIZATION OF ENZYMATIC HYDROLYSIS CONDITIONS FOR ANTIBACTERIAL PEPTIDES PRODUCTION AGAINST PANTOEA SPP. CAUSING RICE LEAF BLIGHT

2023-09-18T13:09:57+08:00

The Central Composite Design (CCD) within the Response Surface Methodology (RSM) was applied to optimize the enzymatic hydrolysis process. This process used Alcalase® to hydrolyze Bactronophorus thoracites protein with the goal of maximizing its antimicrobial effects. Four distinct parameters were identified as independent variables: pH (A: 8.5–10.5), temperature (B: 45–65 °C), hydrolysis time (C: 120–360 min), and enzyme-to-substrate ratio (D: 1.45%–2.65% w/v). Meanwhile, the antimicrobial activity was chosen as the response variable, specifically against Pantoea ananatis (Y₁) and Pantoea stewartii (Y₂). According to the findings, the constructed quadratic polynomial model showed a significant correlation with the experimental data, as evidenced by the coefficient of determination (R²) values for antimicrobial activity: Y₁ being 0.9893 (p < 0.0001) and Y₂ at 0.9848 (p < 0.0001). Optimal antimicrobial activity for Bactronophorus thoracites protein hydrolysates (BTPH) was recorded at 46.748% against P. ananatis and 40.768% against P. stewartii. This result was observed under the optimal conditions of pH 9.5, temperature 55ºC, hydrolysis duration of 240 minutes, and 2.05% w/v enzyme-to-substrate ratio. There was a notable alignment between the actual and predicted values from our models, with the Residual Standard Error (RSE) values falling under 5%. Furthermore, the established Minimum Inhibitory Concentration (MIC) was 250µg/mL, and the Minimum Bactericidal Concentration (MBC) was 500µg/mL for both P. ananatis and P. stewartii. In conclusion, the findings suggest that the refined BTPH has great promise as an effective bioactive component for agricultural use.

HYDROTHERMAL SYNTHESIS OF NITROGEN-DOPED CQDS OF RUBUS NIVEUS LEAVES FOR FLUORESCENT pH SENSING AND PHOTOCATALYTIC APPLICATIONS

2023-09-19T14:43:57+08:00

The development of a fluorescent pH sensor and the treatment of wastewater with nanoparticles are both critical topics. The variation in pH impacts the morphology and subsequent properties of the nanoparticles, which are used for their utilization in various fields and the second one gives a better treatment approach for industrial waste entities.

The present study examines the effects of these variables on the biologically produced nitrogen-doped carbon quantum dots (NCQDs). Hydrothermal process was performed for the synthesis of the same by using Rubus-niveus leaf extract as a precursor. The UV-Vis spectroscopy analysis shows absorption spectra in the wide range of 200 nm to 800 nm and shows prominent peaks at 236 nm and 392 nm, respectively. Further, the direct energy band gap of 3.65eV was analysed for NCQDs. The SEM image shows flower-shaped particles, and FT-IR analysis indicates the existence of amide, CHO, N-H, and C-N functional groups. XRD pattern showed that the surface morphology of NCQDs is amorphous in nature. A good response was found in the variation of fluorescence intensity with the pH values, confirming the possibility of NCQDs serving as pH sensors. Rhodamine-B (Rh-B) dye's reaction kinetics was revealed for the purpose of analyzing the potential of NCQDs for the degradation of commercial dyes and found to be followed by pseudo-first order kinetics with the correlation coefficient of 0.80.

GREEN ROUTE SYNTHESIS OF COPPER OXIDE (CuO) NANOPARTICLES FOR THE DEGRADATION OF COMMERCIAL DYES USING VICIA FABA LEAF EXTRACT

2023-06-22T15:41:55+08:00

The release of toxic dyes into water effluents by various industries has become a global concern. Therefore, developing novel, straightforward, and economically viable methods or materials for purifying these hazardous pigments is imperative. This study aims to synthesize copper oxide nanoparticles (CuO-NPs) through a green route using Vicia faba leaf extract. UV-Vis spectroscopy reveals an absorption band ranging from 200 nm to 300 nm, with a major absorption peak at 212 nm and an energy band gap of 5.29 eV. FTIR, SEM, EDX, and XRD techniques characterise the synthesised CuO nanoparticles. FTIR analysis identifies functional groups including hydroxyl (OH), aromatic C-H, C=C stretching, carbonyl (C=O), and Cu-O stretching vibrations. Scanning electron microscopy reveals flower-like particles, while EDX analysis confirms the formation of CuO nanoparticles. The XRD pattern indicates a crystalline structure with an average particle size of 27.44 nm. A plot of (αhν)² versus photon energy (hν) was generated to determine the energy band gap, yielding a value of 5.29 eV. Rhodamine-B and methylene blue (MB) dyes were employed to evaluate the photocatalytic degradation of the synthesized CuO-NPs, resulting in correlation coefficients of 0.7154and 0.9702, respectively. Furthermore, the rate constants of these dye reactions were found to be 0.0406min^-¹ and0.0343 min^-¹.

DEVELOPMENT OF A SPECTROPHOTOMETRIC DETERMINATION OF PREDNISOLONE IN DIFFERENT DOSAGE FORMS

2023-08-01T10:31:07+08:00

A sensitive, accurate, and affordable colorimetric method was developed for assaying prednisolone (PRZ) in various medicinal forms. The procedure involves the oxidation of PRZ by ferric ions, followed by complexation of the resulting ferrous ions with ferricyanide to produce a greenish-blue product. Common complexation conditions were thoroughly investigated. The mole ratio of FeCl₃·6H₂O to K₃Fe(CN)₆ was 8:1. The proposed mechanism of complexation was suggested and considered. Various parameters were optimized, including the reduction of the colorimetric reaction temperature to 50°C and the duration of heating and analysis to 20-30 minutes. The calibration curve was linear over the range of 1-60 µg/mL. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.5 μg/mL and 1 μg/mL, respectively. Spiking actual samples with standard PRZ showed recoveries within the 97.3-100.1% range. The method exhibited high precision, with an RSD% of less than 1.5%. Additionally, the study confirmed that common pharmaceutical excipients did not interfere. Real medicinal samples, including tablets, syrup, eye drops, and creams, were successfully examined for direct analysis of PRZ using the developed methodology, demonstrating its suitability for routine analysis of various PRZ-containing drug formulations.

MULTI-ENTITY STOCK DEPENDENT MODEL WITH CAPACITY AND MANUFACTURE COST RESTRAINT’S

2023-03-15T21:05:01+08:00

Inventory has an impact on the manufacturing process as well as supply chain operations. The fundamental goal of this research paper is to optimize the cost associated with inventories and to provide flow less continuous production process in time. Normally, demand rate of any entity in inventory control model are treated as predictable and at the same time constant too, and that the cost associated to unit inventory must be independent and non-variable in nature. Nevertheless, in practical circumstances, the unit price and demand rate of an entity may be interconnected. When the asking for an article is enormous, an entity is manufactured in huge quantities and the static charges of manufacturing being diffused over a multiple component. Henceforth, per unit article cost decreases significantly. i.e., per unit article cot and the demand of an article are related under inverse variation. So, better to consider the demand rate of an article as a variable constraint than to fixed one. In this research article, a mathematical model for multiple articles through permitted and restricted shortage and per article cost based on demand accompanied by upper and lower limits viz restricted storage space and manufacturing expenses has been constructed. Overall, investigating the simultaneous effect of storage space and manufacturing expenses in an inventory model provides valuable insights that enable cost optimization, resource allocation, capacity planning, and risk mitigation. It helps companies make informed decisions and improve their overall operational efficiency and profitability. The Multi-Entity Stock Dependent Model with Capacity and Manufacture Cost Restraints can be customized and used in a variety of sectors that include managing inventory across numerous entities and complicated supply chain networks. Here are a few examples of industries that can benefit from such a model: manufacturing industry, the retail and distributor sector, e-commerce companies, pharmaceutical and healthcare industry, automotive industry and food and beverage industry. The article cost is explored at this juncture in a fuzzy atmosphere and solutions of the model being obtained through KKT condition. Finally, a conclusion is offered in the final portion.

ANALYTIC STUDY OF THERMOHALINE CONVECTIVE STABILITY IN A COUPLE-STRESS FLUID

2023-03-20T19:11:57+08:00

This work investigates nonlinear analysis for thermohaline convective stability in a steady, viscous, incompressible couple-stress fluid by performing a generalized energy method. It is observed that the linear and nonlinear threshold that reflects the physics of the onset of convection is the same. The couple stress and solute gradient are seen to have a stabilizing impact on the system.

CONSTRUCTING QUANTUM ANGULAR MOMENTUM L3 IN SPECIFIC DIRECTION BY USING U(1) GROUP

2023-07-13T16:50:18+08:00

The purpose of this work is to investigate the mathematical structure of finite quantum angular momentum in a specific direction L₃which can be constructed from the representation of the U(1) group. The angular momentum eigenstate is invariant under Abelian rotation symmetry. The character group of U(1) is constructed to show that there exists an additive unitary operator for the angular momentum eigenstate, and the rotation eigenstate is invariant under it. The Weyl relation is proved by showing that the angle and angular momentum L₃ are the canonical conjugate pair of observables.

MATHEMATICAL MODEL OF NICKEL-GRAPHENE COMPOSITE INKS FOR JETTING PROPERTIES IN INKJET PRINTING

2023-08-13T11:11:17+08:00

The droplet formation process in inkjet printing is studied numerically and verified through a simulation model. The droplet formation process decides the printing quality of the coating, and a mathematical model is developed to understand the complete process from droplet formation to detachment. The Navier-Stokes equation is used to mathematically derive the droplet radius (r_numerical). COMSOL multiphysics is used for simulation and the radius (r_simulation) is calculated from the droplet mass. The r_numerical and r_simulation are compared for inks containing nickel, graphene, and nickel-graphene composite ink it is observed that the composite ink radiuses have the lowest difference (r_simulation- r_numerical =0.085µm). A droplet is formed at 1.47mm from the nozzle inlet, for nickel-graphene ink, and after 1.5mm for other pristine inks. The results are verified through Z number, velocity profile, and droplet mass. The droplet formation observed from the velocity profile is earliest at 120µs. It is seen that a stable droplet is generated at 100µs for nickel-graphene ink and at 200 µs for individual inks.

NUMERICAL ASSESSMENT OF SOME SEMI-ANALYTICAL TECHNIQUES FOR SOLVING A FRACTIONAL-ORDER LEPTOSPIROSIS MODEL

2023-11-20T03:53:22+08:00

This research aims to apply and compare two semi-analytical techniques, the Variational Iterative Method (VIM) and the New Iterative Method (NIM), for solving a pre-formulated mathematical model of Fractional-order Leptospirosis. Leptospirosis is a significant bacterial infection affecting humans and animals. By implementing the VIM and NIM algorithms, numerical experiments are conducted to solve the leptospirosis model. Comparing the obtained findings demonstrates that VIM and NIM are effective semi-analytical methods for solving systems of fractional differential equations. Notably, our study unveils a crucial dynamic in the disease's spread. The application of VIM and NIM offers a refined depiction of the biological dynamics, highlighting that the susceptible human population gradually decreases, the infectious human population declines, the recovered human population increases, and a significant rise in the infected vector population is observed over time. This nuanced portrayal of the disease's dynamics is crucial for understanding the intricate interplay of Leptospirosis among human and vector populations. The study's outcomes contribute valuable insights into the applicability and performance of the methods in solving the Fractional Leptospirosis model. Results indicate rapid convergence and comparable outcomes for both methods.

INVESTIGATION OF WETTABILITY, ANTIBACTERIAL ACTIVITY, THERMAL INSULATION, AND MECHANICAL CHARACTERISTICS OF ELASTOMER BLEND ADHESIVES WITH HIGH-DENSITY FIBERBOARD WOOD AND ALUMINUM

2023-08-25T23:51:39+08:00

Attention has recently been given to finding alternative and sustainable raw material sources for wood and metal adhesives, such as polyvinyl alcohol (PVA), corn starch (CS), arabic gum (AG), and dextrins (D). Modifying polymer dispersion using unique substances, such as modifying reactive elastomer liquid (EL) using PVA, CS, AG, or D results in sufficiently moisture-resistant adhesive joins. In the present study, the physical characteristics of EL/blended with the natural polymers PVA, CS, AG, and D, based on high-density fiberboard (HDF) wood and aluminum (Al) adhesives and coatings, were investigated and compared to those of pure EL. The EL was blended with PVA, CS, AG, or D at a ratio of 60/40 (w/w) to form EL/blends. The chemical structures, surface and interface morphology, adhesion strengths (including shear strength and pull-off strength), surface roughness, wettings, color intensity, and thermal insulation of the prepared EL and EL/blends were investigated. A scanning electron microscopy (SEM) investigation confirmed filler dispersion and adhesion between the blends, and coated HDF wood, or Al. The developed EL/AG blend had a pull-off strength of 144±5 and 102±3 MPa and a shear strength of 771±11, and 52±3 N with HDF wood and Al substrate, respectively. The EL/PVA blend had a maximum surface roughness value 4.57 µm, and its average water contact angle (WCA) was 85.6°. A plasma jet was used to treat the surface roughness and hence the wettability of the pure EL and the EL/blends, for example, plasma treatment decreased the roughness of the EL/AG blend from 4.36 to 3.28 μm. WCA, and hence wettability, was also significantly influenced by plasma treatment, for example, plasma treatment decreased the WCA of the pure EL from 71.7±0.4° to 30.7±0.7°. The lightness value of the EL/blends was less than that of the pure EL, indicating that (the color adhesives have darkened). Similarly, the yellowness-blueness and redness-greenness values of the EL/blends were greater than those of the pure EL,( rendering the blended adhesives more reddish and bluish). The EL/AG blend was found to have a minimum thermal conductivity (of 0.27 W/m.K), indicating maximum insulation.

AUTOMATED LEAK AND WATER QUALITY DETECTION SYSTEM FOR PIPED WATER SUPPLY

2023-11-05T21:44:26+08:00

The volume of water loss because of leakage in the conveyance pipe has been alarming. Old and poorly constructed pipelines, inadequate corrosion protection, poorly maintained valves, and mechanical damage contribute to leakage. Water-carrying pipes were buried underground, so tracing leak points manually could be tasking, if not impossible. This work was to report on the effectiveness of a developed Automated Leak and Water Quality Detection (ALWQD) system. This device can detect leaks in the piped water system automatically and can also report any deterioration in the quality of water that flows through affected pipes. The ALWQD consisted of several drainpipe connections, pipe accessories, electronic components, and sensors to monitor water quality impairment. The control signal was the solenoid valves that interfaced with the ESP-32 microcontroller boards placed on the pipe manifold at intervals, along with water quality monitoring sensors of turbidity, Total Dissolved Solids (TDS), and pH. The fabrication and testing of the device followed standard procedures. Testing of ALWQD was done at 0, 5, and 10 minutes under load and no-load conditions, with average variation in reading recorded after three trials. The findings indicated that the efficiency of ALWQD was between 70% and 80%, which could be improved upon. The trend in the results of the monitored parameters was not different from that of similar previous work. Leaks caused pressure drops and disallowed the full flow of water found at pipe joints, which could be a pathway for the intrusion of contaminants into the water conveyance system.

DETERMINATION RISK OF BREMSSTRAHLUNG RADIATION PRODUCED BY BETA-RAY

2023-09-08T21:52:47+08:00

When interacting with absorption materials, beta rays, which are emitted by isotopes, are harmful because bremsstrahlung (braking) radiation is produced. Therefore, the efficiency of a shielding material can be improved by considering the bremsstrahlung radiation generated by the material’s beta ray absorption. In this study, to determine the risk of bremsstrahlung radiation produced by beta rays, the fractions of beta energy transformed into bremsstrahlung radiation were calculated for beta emitters in the energy ranges of 0.0026–0.1734, 0.205–0.694, and 0.9345–2.640 MeV, using five different absorption materials (₁₃Al, ₂₆Fe, ₄₈Cd, ₇₄W, and ₈₂Pb). The relationship between the fractions of beta energy transformed into bremsstrahlung radiation by the five shielding materials and the maximum energies of some beta emitters was studied to determine the most suitable beta-ray shielding materials to effectively minimize bremsstrahlung radiation. The results showed that the fractions of beta energy transformed into bremsstrahlung radiation increased as the beta energy and the atomic number of the shielding material increased. The fraction of beta energy transformed into bremsstrahlung radiation in ₁₃Al ˂ ₂₆Fe ˂ ₄₈Cd ˂ ₇₄W ˂ ₈₂Pb.Therefore, beta ray shields should be made with low atomic number materials to reduce the generation of bremsstrahlung radiation. Practically, beta shields made from materials with atomic numbers greater than 13 are rarely employed; notably, aluminum successfully decreased the production of bremsstrahlung radiation. However, it is also necessary to use materials with medium and high atomic numbers as secondary beta shields to reduce the effect of the bremsstrahlung radiation photons formed by the interaction between beta rays and shielding materials.

COMPUTATION OF RAIN-INDUCED ATTENUATION AT CENTIMETRIC WAVE BAND FOR SLANT PATH COMMUNICATION IN NORTH CENTRAL NIGERIA

2023-03-01T08:18:47+08:00

In this paper, five globally recognised rain attenuation models for slant path communication are considered in order to compute the amount of attenuation and obtain the optimal rain attenuation models for North Central region of Nigeria. The models are Bryant, Garcia-Lopez, ITU-R P.618-9, Simple Attenuation and Svjatogor. These models were evaluated at Ku and Ka-bands and at three elevation angles of 55^o, 42.5^o and 23^o. 5-minute integration time rainfall data obtained from the Tropospheric Data Acquisition Network (TRODAN), Anyigba, Nigeria was converted to 1-minute integration time using Lavergnat and Gole rain rate model. Predictions were made for circularly polarised signals at different percentages of time of the year. The cumulative distribution of rain attenuation computed showed that attenuation values generally ranged between 9 and 19 dB at time percentage exceedance of 0.01% for the Ku-band, while it ranged between 21 and 41 dB at 0.01% for the Ka-band. Also, computations by the Garcia-Lopez and Bryant models were in agreement with the ITU-R P.618-9 model, while the Simple Attenuation and Svjatogor models underestimated the computed rain attenuation values at every percentage of time in all the stations considered.