Proceedings of the Pakistan Academy of Sciences: A. Physical and Computational Sciences

Study of Newly Synthesized Pyridinium-based Cationic Surfactants for Drug Interaction and Antibacterial Activity

Sat, 28 Dec 2024 00:00:00 +0000

Two pyridinium-based new cationic surfactants have been synthesized by the reaction of 2-methylpyridine and 3-methylpyridine with an alkyl halide (1-bromoctadecane) using dry toluene as a solvent to get the compounds, N-(n-octadecyl)-2-methylpyridinium bromide (A1) and N-(n-octadecyl)-3-methylpyridinium bromide (A2), respectively. The synthesized samples were characterized by using various spectroscopic techniques. The synthesized compounds showed a critical micelle concentration in a very low-value range (0.111 mM to 0.125 mM), proving the synthesized compounds' best surface-acting ability. Both compounds exhibited limited antibacterial activity across various bacterial strains, with inhibition zones ranging from 3 to 7 mm. The change in Gibb’s free energy (ΔG) was also calculated from their binding constant (K_b) for samples A1 (-10.0 kJ/mol) and A2 (-19.37 kJ/mol). The samples demonstrated spontaneous interactions with the drug molecules, which proved the efficient bioavailability of the drug due to the best incorporation of drug molecules with the aggregated monomers of surfactant molecules.

Measurement of Uranium Concentrations in the Soil Samples of Nineveh Province, Iraq Using CR-39 Detector

Malik H. Kheder, Hanaa N. Azeez — Fri, 27 Dec 2024 00:00:00 +0000

The physiological influence of radiation, which may induce cancer, makes the radioactive field vital to human health. Radon, which is hazardous to both humans and the environment, is deposited in soil via uranium decay. Extended exposure to elevated levels of alpha radiation, primarily radon, causes lung cancer. Thus, research is necessary to observe how the levels of human exposure vary. In evaluating natural exposure radiation, it is essential to control the quantity of radionuclides in the soil by determining the radioactivity level from these sources. Twenty samples of soil from different places in the Nineveh province in northern Iraq were analyzed for uranium content by the CR-39 nuclear track detector. These samples had radon concentrations ranging from 27.221 to 59.407 Bq.m^-3, and the mean is 38.917 Bq.m^-3. This mean value is below the level of reference limits 100 Bq.m^-3of the World Health Organization (WHO). Uranium levels ranged values from 0.129 to 0.281 ppm, with a mean of 0.182 ppm. Findings demonstrate that the natural radiations in the region are within the permissible range, as shown when comparing the results to global averages, the uranium concentration levels fell below the average of global value 2.8 ppm, and below the acceptable limit of 11.7 ppm.

Theoretical Evaluation of Silicon Crystal Growth Using Gallium Solvent

Alijon Razzokov, Khushnudbek Eshchanov — Sat, 28 Dec 2024 00:00:00 +0000

Semiconductor materials are of great importance throughout the world. Silicon crystals are this field's most widely used and relatively inexpensive material. Obtaining low-dislocation and defect-free silicon crystals is one of the current issues, and we theoretically investigated the production of low-defect silicon crystals from silicon-gallium melt. We considered the defects that appear in the silicon crystals grown from the solution related to the large-sized silicon nanoclusters involved in the crystal formation based on the obtained results, we showed the conditions for obtaining silicon crystals with few defects from the silicon-gallium solution.

Atomistic Simulation of Temperature-Dependent Interfacial Diffusion between Solid Nickel and Liquid Aluminum

Fri, 27 Dec 2024 00:00:00 +0000

The performance and durability of welded joints are directly influenced by interfacial diffusion between the metals involved, making it essential to investigate the effect of temperature on these processes. The present research examines temperature-dependent diffusion mechanisms at the interface between solid nickel and liquid aluminum using molecular dynamics simulations. Investigations were conducted at 1200, 1300, 1400, and 1500 K to explore the influence of temperature on atomic mobility and interfacial mixing. Radial distribution function analysis revealed a significant increase in the diffusion of nickel atoms into the aluminum phase with increasing temperature, indicating enhanced atomic interactions at the interface. The mean square displacement analysis supported these findings, showing that aluminum atoms were more mobile than nickel atoms at lower temperatures, while nickel atoms exhibited a faster diffusion rate with increasing temperature, surpassing aluminum in mobility. This trend is reflected in the diffusion coefficients, which exhibit a temperature-dependent increase in the diffusion rate of the nickel atoms. These results emphasize the role of temperature in controlling the diffusion dynamics at the solid–liquid interface. The insights gained from this study are critical for optimizing processes, such as dissimilar metal welding, where precise control over interfacial diffusion is essential for achieving the desired material properties and ensuring the structural integrity of nickel–aluminum joints in high-temperature applications.

Uranium, Polonium-218, and Polonium-214 Concentrations in Serum Samples of Cancer Patients at Al-Najaf Governorate

Sat, 28 Dec 2024 00:00:00 +0000

This research examines the concentrations of uranium (U_C), polonium of POW (²¹⁸Po and ²¹⁴Po on the wall of the irradiation container), and polonium of POS (²¹⁸Po and ²¹⁴Po on the surface of the irradiation container) in serum samples of male and female cancer patients and health human in the Al-Najaf Governorate of Iraq. U_C, ²¹⁸Po, and ²¹⁴Po were determined using a track detector technique with a CR-39 detector. The mean values of U_C for male and female cancer patients were 0.110 ± 0.024 ppb and 0.099 ± 0.013 ppb, respectively. The POW's average values for male and female cancer patients were 3.885 ± 2.132 Bqm^-3and 2.958 ± 1.146 Bqm^-3, respectively while the mean values of POS for male and female cancer patients were 0.702 ± 0.386 Bqm^-3 and 0.535 ± 0.207 Bqm^-3, respectively. The results show that the mean concentrations of U_C, ²¹⁸Po, and ²¹⁴Po are significantly higher (p < 0.001) in male and female cancer patient groups compared with the healthy group. Also, the mean values of U_C, ²¹⁸Po, and ²¹⁴Po concentrations do not correlate with variables for male and female patient groups. Therefore, the concentrations of U_C, ²¹⁸Po, and ²¹⁴Po in cancer patients and healthy groups in the present study were not significant in terms of gender. According to the ICRP and WHO report, the concentrations of uranium and polonium in all samples of the current study were within the accepted limits (uranium = 0.810 ppb) and (polonium = 550 Bqm^-3), So the serum samples of male and female cancer patients and healthy in the Al-Najaf Governorate of Iraq were not contaminated with uranium.

Study of Newly Synthesized Pyridinium-based Cationic Surfactants for Drug Interaction and Antibacterial Activity

Sat, 28 Dec 2024 00:00:00 +0000

Two pyridinium-based new cationic surfactants have been synthesized by the reaction of 2-methylpyridine and 3-methylpyridine with an alkyl halide (1-bromoctadecane) using dry toluene as a solvent to get the compounds, N-(n-octadecyl)-2-methylpyridinium bromide (A1) and N-(n-octadecyl)-3-methylpyridinium bromide (A2), respectively. The synthesized samples were characterized by using various spectroscopic techniques. The synthesized compounds showed a critical micelle concentration in a very low-value range (0.111 mM to 0.125 mM), proving the synthesized compounds' best surface-acting ability. Both compounds exhibited limited antibacterial activity across various bacterial strains, with inhibition zones ranging from 3 to 7 mm. The change in Gibb’s free energy (ΔG) was also calculated from their binding constant (K_b) for samples A1 (-10.0 kJ/mol) and A2 (-19.37 kJ/mol). The samples demonstrated spontaneous interactions with the drug molecules, which proved the efficient bioavailability of the drug due to the best incorporation of drug molecules with the aggregated monomers of surfactant molecules.

Fractional Order ANFIS Sliding Mode Controller for Two-Time Scale Dynamics in PWR

Arshad Habib Malik, Feroza Arshad, Aftab Ahmad Memon — Sat, 28 Dec 2024 00:00:00 +0000

In this research work, a novel model of Pressurized Water Reactor (PWR) dynamics is developed with special emphasis on nuclear fuel burn-up or fuel depletion dynamics. PWR dynamics is identified and decomposed into fast and slow dynamic modes for the first time in this research work. The stiff two-time scale reactor dynamics problem is addressed, and a new sophisticated fractional order two-time scale sliding mode controller is designed. The PWR dynamics is uncertain due to three distinct operating conditions of nuclear reactor core as Beginning of Core (BOC), Middle of Core (MOC) and End of Core (EOC) synthesizing a variable structure model. The model uncertainties are estimated using Adaptive Neuro-Fuzzy Inference System (ANFIS) while different reactivity components are addressed as active disturbance or measurement noise. The novel robust control design problem is a big challenge in this research. The proposed controller is designed, tested and validated against benchmark data and found excellent in performance.

Resilience of Antibiotic Usage and Vital Signs in COVID-19 Patients: A Post-Pandemic Analysis in Pakistan

Muhammad Islam, Imtiaz Ahmed, Muhammad Shehzad, Kashif Nadeem — Fri, 27 Dec 2024 00:00:00 +0000

COVID-19 has had a profound global impact, wreaking havoc on economies and causing a significant loss of lives. Pakistan has also faced severe consequences from the pandemic. To combat the virus, antibiotics such as Azithromycin, Ceftriaxone, Cefixime, Clarithromycin, Levofloxacin, Moxifloxacin, Meropenem, Tazobactam, Tienam, and Vancomycin have been administered to COVID-19 patients. Various vital signs such as temperature, respiratory rate, oxygen saturation, pulse rate, and blood pressure have been closely linked to the symptoms of COVID-19. This study examines the impact of antibiotic usage and vital signs on the survival and mortality of COVID-19 patients using a dataset collected from four major hospitals in Pakistan. The analytical approach includes descriptive analysis, a t-test, and a chi-square test of independence. The originality of this research lies in its comprehensive exploration of the relationship between specific antibiotics and the monitoring of vital signs in the context of COVID-19. It offers a systematic analysis of existing information to derive meaningful insights. Azithromycin emerged as the predominant antibiotic used to treat COVID-19 patients in Pakistan, with other antibiotics showing varying usage patterns. Strong, significant associations were identified between Azithromycin, Tazobactam (Tanzo), and the binary response variable (died/alive). Regarding vital signs, significant relationships were observed for patient age, systolic blood pressure, and diastolic blood pressure when compared to the response variable. This study's findings underscore the importance of Azithromycin and Tazobactam in COVID-19 treatment and highlight the role of vital signs in predicting patient outcomes.

Geostatistical Model Development and Assessment of Tidal Stream Energy Resources: A Case Study of Indus Delta, Pakistan

Mirza Salman Baig, Ambreen Insaf, Saba Javaid, Zaheer Uddin — Fri, 27 Dec 2024 00:00:00 +0000

In this paper, an approach is applied by using the Geographical Information System for the development of geostatistical models to assess available tidal stream energy resources of the Indus Delta Creek system. The mean spring tidal current of twelve different locations in the Indus Delta Creek system (Pakistan) is utilized to develop geostatistical models for the prediction of tidal currents at different locations where no data was available. Models are validated and an investigation of prediction error is carried out to select the best model. For the prediction of tidal stream data, various models are collated namely (i) Circular (ii) K-Bessel (iii) Stable, and (iv) Exponential. These models show the range of mean spring ebb current between 1.9 m/s and 2.12 m/s and the range of mean spring flood current between 1.4 m/s and 1.65 m/s. The stable model for mean spring flood current and circular model for mean spring ebb current agreed with the observed ones. Furthermore, the tidal kinetic power density model and bathymetry model are also developed for the selection of potential sites within the study area. Based on results achieved from geostatistical and bathymetry models; deployment of the suitable turbine at the study area is proposed and generation of 2754.7 MW electric power is estimated.

Investigating the Effects of Horizontal Transition with Student-Preferred Learning Materials in a Virtual Biology Laboratory

Asad Ullah Khan, Aftab Alam, Shah Khalid, Sehat Ullah, Fakhr ud Din — Sat, 28 Dec 2024 00:00:00 +0000

Adaptive Virtual Learning Environments (VLEs) present customized teaching materials to individual students which help them to achieve their learning goals and serve quite a vital role in virtual learning environments. In this paper, we present a new student-centered learning approach in a three-dimensional (3D) virtual biology laboratory (VBIOLAB). The approach is based on the concept of horizontal transition with student preference (HTWSP) implemented with the help of VBIOLAB. The HTWSP is based on the concept of allowing students to choose their preferred learning styles according to their needs and pace instead of automatically adapted aids. HTWSP allows students to stay in a certain module and attain more information about that learning module through various aids of their choice. To go to the next learning module there is a mechanism of vertical transition which allows a student to make quick progress by skipping the details about a certain module. Intermediate-level students participated in experiments that compared the proposed system with an adaptive virtual laboratory. Experimental results indicated that 75% of students improved their examination scores through the use of VBIOLAB. Data from the system usability scale (SUS) and the subjective rating supported greater participation, motivation, and effectiveness in learning using VBIOLAB. The experimental results reveal that this approach is effective and vital to utilize to enhance students’ learning in 3D-VLEs.