Comparative Assessment of Ambient Air Quality of Major Cities of Pakistan

The deterioration of ambient air quality is one of the emerging environmental problems in developing countries of South Asia. Unplanned urbanization, population growth, degradation of vegetation cover and industrial and vehicular emissions, particularly in urban areas, have resulted in substantial rise in the level of air pollutants and emission sources. This study focused on monitoring of different cities as per traffic volume and flow. Air quality monitoring was conducted on hourly basis to determine the major parameters; i.e. PM₁₀, NO_x, SO₂, CO by using fixed station for 8 h from 1:30 pm to 9:30 pm. All the measuring values were then compared with the National Environment Quality Standards (NEQS) and Air Quality Index (AQI). Results revealed that the concentration of PM₁₀ at the selected areas of these cities ranged from 156 to 390 μg/m³, CO ranged from 1.18 to 6.01 mg/m³, and NO_x ranged from 32.65 to 129.47 μg/m³. It was evident that all these concentration had been higher than the permissible limits of NEQS, whereas only SO₂ was found within the permissible limits (15.60–110.52 μg/m³⁾. Air Quality Index (AQI) of all the designated points of cities was also assessed, and most of the vehicular and commercial areas had shown unhealthy and severe conditions ranging from 191 to 320, respectively.

     

Hiding in Plain Sight: Virtually Unrecognizable Memory Phenotype CD8+ T cells

Virtual memory T (T_VM) cells are a recently described population of conventional CD8⁺ T cells that, in spite of their antigen inexperience, express markers of T cell activation. T_VM cells exhibit rapid responsiveness to both antigen-specific and innate stimuli in youth but acquire intrinsic antigen-specific response defects in the elderly. In this article, we review how the identification of T_VM cells necessitates a re-evaluation of accepted paradigms for conventional memory T (T_MEM) cells, the potential for heterogeneity within the T_VM population, and the defining characteristics of T_VM cells. Further, we highlight recent literature documenting the development of T_VM cells as a distinct CD8⁺ T cell lineage as well their biological significance in the context of disease.     

Refuse-derived fuels as a renewable energy source in comparison to coal,rice husk,and sugarcane bagasse

The calorific potential of refuse-derived fuels (RDFs) was investigated with different coals, rice husk, and sugarcane bagasse. Carbon-sulfur analysis, gross calorific value (kJ/kg), and proximate analysis (%) were carried out. Total carbon of coal samples was found to be in the range from 62.65 to 79.19%, while RDF samples were ranged from 40.21 to 57.34% which were almost similar to rice husk (49.13%) and sugarcane bagasse (46.13%). Comparison of the total sulfur content of the coal (Duki) (10.52%) was very high as compared to RDF samples ranged from 0.17 to 0.46% and almost similar to rice husk (0.34%) and sugarcane bagasse (0.187%), while other coal samples ranged from 2.1 to 4.5%. The gross calorific value of the coal (Duki) (6,163 kJ/kg) was higher to other coal samples ranged from 4,935 to 4,972 kJ/kg, while found to be almost double to rise husk (3,518 kJ/kg), sugarcane bagasse (3,285 kJ/kg), and RDF samples (3,125–4,689 kJ/kg). The moisture content, volatile matter, and ash content were found higher in RDF 1 (42.14%), RFD 2 (66.55%), and coal (stone) (33.14%), respectively. Appropriate gross calorific value and very low sulfur content of the RDFs, especially RDF 2, appeared adequate to be used as a fuel with a lesser pollution potential and as an alternative fuel in mega cement industry of Pakistan.     

A cost-effective approach to synthesize NiFe2O4/MXene heterostructures for enhanced photodegradation performance and anti-bacterial activity

A cost-effective ultrasonication approach was employed to synthesize NiFe₂O₄/MXene heterostructures. The as-synthesized heterostructures demonstrated outstanding photodegradation performance and anti-bacterial activity as compared to individual NiFe₂O₄ (NiFe) or MXene. The NiFe nanoparticles (NPs) helped in effectively preventing the re-stacking of MXene flakes and in increasing the surface area of the heterostructure. The obtained sheet-sheet linkage provided an admirable opportunity for excellent wastewater treatment and antibacterial activity. The photocatalytic degradation of organic pollutants by the introduced photocatalyst NiFe/MXene heterostructures has been observed to be about 4 and 6.72 times boosted compared to MXene and NiFe, respectively. Furthermore, the heterostructure materials demonstrated outstanding anti-bacterial activity against gram negative E-coli bacteria, while the mechanism of methylene blue dye degradation by NiFe/MXene was clarified through kinetic studies of the degradation process. We hope this work will be considered a significant scientific contribution for young researchers dealing with water desalination.     

Determination and dispersion of pollutants from different fuel types used in brick kilns by using Gaussian’s plume model

The present study was conducted to compare the concentration of pollutants and their level of dispersion in the atmosphere from the plume of brick kilns using different types of fuels. For this purpose, two brick kilns were selected based on their fuel type. One type of fuel was good quality coal (F1) and the other was low-quality coal mixed with wood (F2). The air emissions data illustrated that carbon monoxide concentration was more (108 ± 0.90 ppm) in the plume of F1 than in the plume of F2 (82 ± 0.98 ppm) and sulfur dioxide was more (1955 ± 3.76 ppm) in the plume of F2 than in the plume of F1 (6 ± 0.07 ppm). The Gaussian plume model showed that plume from good quality coal as fuel (F1) disperses 0.7 ± 0.01 km horizontally and 4 ± 0.03 km vertically whereas the plume from low-quality coal mixed with wood (F2) disperse 1 ± 0.01 km horizontally and 2 ± 0.02 km vertically. Pearson correlation also showed a significant (p < 0.05) difference between both fuel types. These high concentrations can have negative impacts on the atmospheric environment as well as community health.     

Effects of Donor Cell Types on the Development of Bovine Embryos Using Cytoplasm Injection Cloning Technology

Cytoplasm injection cloning technology (CICT) is an efficient technique for evaluating the developmental potential of cloned embryos. In this study, we investigated the effects of donor cell type on the developmental potential and quality of cloned bovine embryos. Adult fibroblasts (AFs) and embryonic cells (ECs) were used as donor cells to clone bovine embryos using CICT. We initially used AF cells to develop cloned embryos and then cultured the cloned day-8 blastocysts for 10 days to obtain ECs as donor cells for second embryo cloning. We found that the bovine blastocysts cloned using AF cells had significantly reduced developmental rates, embryo quality, and ratios of inner cell mass (ICM) to the total number of cells compared to those using ECs as donor cells. Furthermore, there were significant differences in the DNA methyltransferase-, histone deacetylation-, apoptosis-, and development-related genes at the blastocyst stage in embryos cloned from AFs compared to those in embryos cloned from ECs. Our results suggest that using ECs as donor cells for nuclear transfer enhances the quantity and quality of cloned embryos. However, further investigation is required in terms of determining pregnancy rates and developing cloned embryos from different donor cell types.     

Bioenergy recovery analysis from various waste substrates by employing a novel industrial scale AD plant

In this novel industrial scale case study, the bioenergy recovery based on sole and mixed cow-buffalo (CBM) and potato waste (PW) substrates has been analyzed in real time, i.e., on-site on a full-scale operational anaerobic digestion (AD) plant. The plant employed in this study is a novel design, consisting of tri-digesters connected via an underground upflow anaerobic sludge blanket (UASB) type lagoon allowing it to function as a continuous-flow reactor. The system has been further equipped with CSTR, microwave heating, gas scrubbers, compression, and storage systems. The highest energy recovery readings were 123.9 m³/1,000 kg, 77 m³/1,000 kg, and 151.6 kWh/1,000 kg in terms of biogas, bio-methane, and electricity generated, respectively, with 75:25 ratio of CBM:PW. Operating with 100% CBM, yields of 79.9 m³/1,000 kg, 47 m³/1,000 kg, and 95 kWh/1,000 kg were obtained. The percentage of recovery in bio-methane production increased on using the mixed substrates, but it was the lowest with a 25:75 ratio of CBM:PW. The electrical power generation efficiency was found to be significantly increased, but not distinctively with the plant aggregate power rating that was probably associated with the variable quality of biogas which was fed to the power generator. A linear regression analysis had shown a significant and positive correlation between the rate of VS removal and biogas yield.     

A novel hybrid spreading and scrambling based multiple access (SSMA) technique for capacity improvement

Telecommunication Systems - Future wireless networks and 5G communication technology aims to provide seamless connectivity for geographical areas having thousands of users within hundreds of meter...