Browsing by Author "Rezaul Islam, Md."

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Analysis of lossy dielectric optical waveguides
(Department of Electrical and Electronic Engineering, BUET, 2006-03) Rezaul Islam, Md.; Alam, Dr. Md. Shah
An efficient vector finite element method with the hybrid edge/nodal triangular element is described in this thesis for the analysis of dielectric optical waveguides with an emphasis to the analysis of loss. The hybrid type element (a combination of linear edge elements and quadratic nodal elements) are used in' the work. The edge element models the transverse fields and nodal element model axial component of field variable. Thus, in the approach a true hybrid mode analysis is ensured. The undesired spurious (non-physical) solutions do not appear anywhere and the approach provides a direct solution for the propagation constant. Since the eigenvalue corresponds to propagation constant rather than frequency, the method can be easily applied to the analysis of lossy waveguides. However in this work, an indirect approach based on perturbation technique is employed for the calculation of loss in optical waveguides. Here, lossless field solutions obtained from the finite element method are used in the perturbation equation to calculate loss in optical rib waveguides and r.ectangular dielectric waveguides. Furthermore, the method is very flexible and can handle a wide variety of problems having sharp metal and/or dielectric edges. The most important is that the sparsity and the bandedness of the matrices are maintained, so high speed computation with large sparse generalized complex eigenvalue problem is possible. But in the work, the need for solving complex eigenvalue problem is eliminated by using the perturbation formula. Finally, the accuracy of this approach is checked by comparing the propagation characteristics of step index dielectric optical waveguides with and without loss.
Green Synthesis of Iron Oxide NPs (IONPs) by Using Aqueous Extract of Parthenium hysterophorus Linnaeus for the In-vitro Antidiabetic and Anti-inflammatory Activities
(2024-11-13) Abdur Rauf; Ahmad, Zubair; Raisham; Ibrahim, Muhammad; Rezaul Islam, Md.; A. Hemeg, Hassan; S. Al-Awthan, Yahya; Bahattab, Omar; Abdur Rahman; Umar, Muhammad; Muhammad, Naveed
The Parthenium hysterophorus Linnaeus is one of the anti-inflammatory and antidiabetic ethnomedicine. Therefore the formulation of this plant as nanoparticles will be fruitful anti-inflammatory and antidiabetic as compared to conventional extract. In the current study, the aqueous kernel extract from Parthenium hysterophorus Linnaeus was subjected to synthesize iron oxide nanoparticles (IONPs) and explored their anti-inflammatory and anti-diabetic potentials. The results indicate that the aqueous kernel extract effectively produced IONPs, which were verified using standard analytical methods. UV-visible spectrophotometer analysis was used to check the formation of IONPs. The Fourier-transform infrared spectroscopy (FTIR) was used to check numerous functional groups from the valuable phytochemicals present in the extract. These functional groups play crucial roles as reducing, capping, and stabilizing agents during the synthesis of IONPs. Additionally, scanning electron microscopy (SEM) were utilized to investigate the surface characteristics of the nanoparticles. Notably, the IONPs fabricated from the extract demonstrated promising anti-inflammatory activity, inhibiting Human RBC by 79% and Heat Induced Hemolysis by 72%, as well as showing anti-diabetic potential with 60% inhibition of yeast glucose uptake and 72% inhibition of α-amylase activity, all at a concentration of 100 μg mL-1. These effects were partly comparable to standard drugs with anti-inflammatory activity of 85% inhibition of Human RBC and 78% inhibition of Heat Induced Hemolysis, and anti-diabetic activity of 67% inhibition of yeast glucose uptake and 78% inhibition of alpha amylase.
Ligand-based drug design against Herpes Simplex Virus-1 capsid protein by modification of limonene through in silico approaches
(2024-05-08) Rezaul Islam, Md.; Shafiqul Islam Sovon, Md.; Amena, Ummy; Miadur Rahman; Hosen, Md. Eram; Kumer, Ajoy; Bourhia, Mohammed; A. Bin Jardan, Yousef; Ibenmoussa, Samir; Fentahun Wondmie, Gezahign
The pharmacological effects of limonene, especially their derivatives, are currently at the forefront of research for drug development and discovery as well and structure-based drug design using huge chemical libraries are already widespread in the early stages of therapeutic and drug development. Here, various limonene derivatives are studied computationally for their potential utilization against the capsid protein of Herpes Simplex Virus-1. Firstly, limonene derivatives were designed by structural modification followed by conducting a molecular docking experiment against the capsid protein of Herpes Simplex Virus-1. In this research, the obtained molecular docking score exhibited better efficiency against the capsid protein of Herpes Simplex Virus-1 and hence we conducted further in silico investigation including molecular dynamic simulation, quantum calculation, and ADMET analysis. Molecular docking experiment has documented that Ligands 02 and 03 had much better binding affinities (− 7.4 kcal/mol and − 7.1 kcal/mol) to capsid protein of Herpes Simplex Virus-1 than Standard Acyclovir (− 6.5 kcal/mol). Upon further investigation, the binding affinities of primary limonene were observed to be slightly poor. But including the various functional groups also increases the affinities and capacity to prevent viral infection of the capsid protein of Herpes Simplex Virus-1. Then, the molecular dynamic simulation confirmed that the mentioned ligands might be stable during the formation of drug-protein complexes. Finally, the analysis of ADMET was essential in establishing them as safe and human-useable prospective chemicals. According to the present findings, limonene derivatives might be a promising candidate against the capsid protein of Herpes Simplex Virus-1 which ultimately inhibits Herpes Simplex Virus-induced encephalitis that causes interventions in brain inflammation. Our findings suggested further experimental screening to determine their practical value and utility.
Modified oxymatrine as novel therapeutic inhibitors against Monkeypox and Marburg virus through computational drug design approaches
(2024-09-28) Rezaul Islam, Md.; Biswas, Suvro; Amena, Ummy; Rahman, Miadur; Islam, Shirmin; Ariful Islam, Md.; Abu Saleh, Md.; Hassan, Hesham M.; Al-Emam, Ahmed; Zaki, Magdi E. A.
Global impact of viral diseases specially Monkeypox (mpox) and Marburg virus, emphasizing the urgent need for effective drug interventions. Oxymatrine is an alkaloid which has been selected and modified using various functional groups to enhance its efficacy. The modifications were evaluated using various computatioanal analysis such as pass prediction, molecular docking, ADMET, and molecular dynamic simulation. Mpox and Marburg virus were chosen as target diseases based on their maximum pass prediction spectrum against viral disease. After that, molecular docking, dynamic simulation, DFT, calculation and ADMET prediction were determined. The main objective of this study was to enhance the efficacy of oxymatrine derivatives through functional group modifications and computational analyses to develop effective drug candidates against mpox and Marburg viruses. The calculated binding affinities indicated strong interactions against both mpox virus and Marburg virus. After that, the molecular dynamic simulation was conducted at 100 ns, which confirmed the stability of the binding interactions between the modified oxymatrine derivatives and target proteins. Then, the modified oxymatrine derivatives conducted theoretical ADMET profiling, which demonstrated their potential for effective drug development. Moreover, HOMO-LUMO calculation was performed to understand the chemical reactivity and physicochemical properties of compounds. This computational analysis indicated that modified oxymatrine derivatives for the treatment of mpox and Marburg virus suggested effective drug candidates based on their binding affinity, drug-like properties, stability and chemical reactivity. However, further experimental validation is necessary to confirm their clinical value and efficacy as therapeutic candidates.
Molecular insights into withaferin A: A holistic approach to cancer therapy
(2024-12-15) Rezaul Islam, Md.; Abdur Rauf; Rakesh, M. Meenakshi; Akash, Shopnil; Fakir, M. Naeem Hossain; Islam, Samiul; Naba, Afifa Farzana; Al-Imran, Md. Ibrahim Khalil; AlOmar, Taghrid S.; Ogaly, Hanan A.; Alzahrani, Hayat E.; Thiruvengadam, Rekha; Thiruvengadam, Muthu
Withaferin A (WA), a significant phytoconstituent of Withania somnifera, belongs to the triterpenoid class of C28-steroidal lactones found in nature. It has been utilized in traditional and native medical systems to treat various diseases such as cancers. It also has pro-apoptotic, anti-inflammatory, metabolic, and anticancer properties. In addition, it interacts with NF-κB, STAT, Hsp90, ER, and p53, thereby suppressing cancer cell growth and reducing the cell cycle at the G2/M stage. This review discusses the pro-apoptotic properties of WA, such as the generation of ROS, activation of PAR-4, development of ER stress, and activation of p53. This provides a comprehensive analysis of the molecular mechanisms of WA, highlighting its intricate effects on cancer cell signaling pathways, apoptosis, and tumor microenvironment (TME) regulation. Moreover, the ability to modify the TME through immune response modulation underscores its importance in comprehensive cancer treatment. The involvement of WA in oncogenic pathways that lead to malignant neoplasms and its potential therapeutic effects when combined with other cancer treatments are promising. This review indicates that WA's strong pharmacological profile, especially in combating cancer, could be advantageous for developing new cancer therapy medications. Furthermore, it emphasizes the potential of WA as a supplement to standard medications and encourages further clinical trials to assess its efficacy and safety in various cancer types. Moreover, it indicates a growing understanding of natural chemicals in cancer therapy, which can be integrated into various treatment methods.
Seismic loss estimation for Sylhet city
(Department of Civil Engineering, 2005-02) Rezaul Islam, Md.; Ansary, Dr. Mehedi Ahmed
For accomplishing comprehensive regional seismic loss estimation, geographic information system (GIS) provides a perfect environment. A GIS has the capability to store, manipulate, analyze, and display the large amount of required spatial and tabular data. By using geographic information system to carry out regional multi-hazard seismic loss estimation for study area where reflection of ground shaking and the secondary site attributes of soil amplification, liquefaction and landslide arc the salient features. The method to combine the different hazards is based on a weighted average approach. This dissertation also covers the development of a comprehensive inventory of building for the Sylhet City. Sylhet City Corporation has twenty-seven Wards in its jurisdiction. Initially a GIS based Ward map is developed. 3611 buildings (14% of the total) arc surveyed in the study area and water pipelines data arc collected from City Corporation office. For mierozonation purpose 167 boreholes with SPT data are collected from different relevant organizations. To verify those data nine boreholes up to a depth of 30m arc carried out. Three past historical earthquakes 1885 Bengal earthquake, 1918 Srimangal Earthquake and 1897 Great Indian earthquake arc used as scenario events for this study. Intensity value obtained for these events is calibrated against attenuation laws to check the applicability of the laws for the study area. Using these laws, bedrock Peak Ground Acceleration (PGA) values arc obtained for study area for different earthquakes. Finally, a bedrock PGA value for the scenario events is selected. PGA in the bedrock level in the study area and boreholes SPT data are used to develop a regional combined seismic hazard map based on site amplification as well as liquefaction and landslide potential hazard. This hazard map is then overlaid and combined with structural inventory maps to produce maps of regional damage distributions. Combining the map of damage distributions with a map of population distributions for the area results in linal regional estimates of direct monetary loss such as building and water line distribution and non-monetary loss such as fatalities and mutinies. The investigations arc carried out for two cases such as based on combined seismic hazard considering local site effects and based on hazard due to ground shaking alone. The expected damage factor for all building decreases from about 59% to about 51% when the effects of liquefaction and landslide arc ignored. The total direct monetary loss decreases by about 9'%. However, there is a tremendous effect of liquefaction and landslide hazards over direct non-monetary loss as Fatalistic and injuries increases by 49% and 43% respectively during night. The final seismic loss estimation appears to be reasonable when compared to recent large earthquakes in urban areas of the world. The GIS-based analysis is useful to engineers, planners, emergency personnel, government officials, and anyone else who may be concerned with the potential consequences of seismic activity in a given region.