[en] Objective: To explore the association of gender with risk factors for cardiovascular diseases among adolescents. Method: The cross-sectional study was conducted 2016-2019 in low-income schools in Karachi after approval from the ethics review board of Dow University of Health Sciences, and comprised adolescents of both genders aged 11-17 years. Anthropometric measurements and lifestyle behaviours were used to generate risk profile for cardiovascular diseases. Data was analysed using SPSS 16. Results: Of the 1195 subjects, 468(39.2%) were boys and 727(60.8%) were girls. The mean age was 13.9±1.6 years. Mean family size was 5.9±3.64. Overall, 989(91.3%) participants consumed soft drinks, 44(4%) were smokers, 340(48.4%) consumed betel nut, 215(32.9%) Pan, 125(21.2%) Gutka and 9(1.7%) Bidi. Of the total, 867(83.3%) participants were physically less active than recommended, and daily screen time was >2 hours among 513(45.7%) participants. Body mass index and body fat percentage were significantly higher among girls (p<0.05). Higher rates of diastolic and systolic blood pressure and hand grip strength were observed in boys compared to girls (p<0.05). Conclusion: Interventional programmes in schools should emphasise the need for healthy lifestyle behaviours, increased physical activity, good eating habits and smoking cessation. (author)

[en] The need of introducing innovative power generation methods is increasing rapidly. The conventional fuel driven methods not only require heavy financial investments, they have also been held responsible for many natural calamities faced by the human population. While the research on better utilizing the renewable resources such as wind, tidal and wave energy etc is underway, the Osmotic Power has been commercially introduced as a new fuel-free energy resource. The energy in the osmotic power is derived from the difference in salt concentration between the fresh water and the salt water. In an osmotic power plant, the river water is used as the fresh water and the sea water is treated as the salt water for getting electric power through osmosis. While the hydroelectric dams can threat irrigation activities in some areas by blocking the water supply, the osmotic plants are situated at locations where the river water falls into the sea and hence cause no water hold-ups. In this paper, we take an in-depth look into the technical methods and the associated challenges of the osmotic power generation. We highlight the scope of osmotic power in Pakistan. We identify important geographical locations in the country which can be ideal for setting up an osmotic power station. (author)

[en] The synthesis of a bis-zwitterionic lamellar hybrid material containing ammonium carboxylate groups is described. Cation-exchange properties of this material towards transition metal and lanthanide ions were studied as well as the regeneration and reuse of the material. (authors)

[en] EPR investigations are performed on mesoporous silica (SBA15) functionalized by Nickel-cyclam complexes (1,4,8,11-tetraazacyclotetradecane groups chelating nickel ions) and on mesoporous titanium dioxide with nitrogen doping. For functionalized silica, the magnetic behaviour of organometallic groups, their mutual interactions and dispersion in the host matrices are compared with respect to the doping rates and the synthesis procedures. The relaxation processes were analyzed from the thermal evolution of the paramagnetic spin susceptibilities and EPR line-widths. Particularly, some samples show the formation of clusters where phonon assisted one dimensional (1D) ferromagnetic ordering occurs below 45 K. For the mesoporous TiO₂, systematic EPR investigations were performed on two main classes of materials with regard to the porosity degrees. The EPR experiments point out the efficiency of EPR method to probe the degree of functionalization of mesoporous silica or the nitrogen doping achievement in TiO₂, and in general to give a valuable feedback to improve the synthesis routes of smart materials.

[en] In this research paper, a comprehensive thermodynamic modeling of a combined cycle power plant is first conducted and the effects of gas turbine inlet fogging system on the first and second law efficiencies and net power outputs of combined cycle power plants are investigated. The combined cycle power plant (CCPP) considered for this study consist of a double pressure heat recovery steam generator (HRSG) to utilize the energy of exhaust leaving the gas turbine and produce superheated steam to generate electricity in the Rankine cycle. In order to enhance understanding of this research and come up with optimum performance assessment of the plant, a complete optimization is using a genetic algorithm conducted. In order to achieve this goal, a new objective function is defined for the system optimization including social cost of air pollution for the power generation systems. The objective function is based on the first law efficiency, energy cost and the external social cost of air pollution for an operational system. It is concluded that using inlet air cooling system for the CCPP system and its optimization results in an increase in the average output power, first and second law efficiencies by 17.24%, 3.6% and 3.5%, respectively, for three warm months of year. - Highlights: • To model the combined cycle power plant equipped with fog inlet air cooling method. • To conduct both exergy and economic analyses for better understanding. • To conduct a complete optimization using a genetic algorithm to determine the optimal design parameters of the system

[en] Electron paramagnetic resonance (EPR) investigations are carried out on mesoporous silica (SBA15) functionalized by Ni-cyclam complexes (1,4,8,11-tetraazacyclotetradecane groups chelating nickel ions). The magnetic behaviour of nickel-cyclam groups, their mutual interactions and dispersions in the mesoporous silica are compared with respect to the doping rates and the synthesis procedures. The spin-spin interactions and the relaxation processes were clarified from the thermal evolution in the temperature range (4 K, 300 K) of the paramagnetic spin susceptibilities and EPR line widths. Thus, the relaxation mechanisms seem marked by the Jahn-Teller effect on the nickel ions mediated by exchange interactions between nearest spins. Isolated Ni-cyclam molecules are involved in some samples while others show the formation of clusters where phonon-assisted one-dimensional (1D) ferromagnetic ordering occurs below 45 K. The performed experiments point out the efficiency of the EPR technique to probe the degree of functionalization of mesoporous silica by Ni-cyclam molecules and to give valuable feedback to improve the synthesis routes.

[en] Mesoporous silica SBA-15 functionalized by (1,4,8,11-tetraazacyclotetradecane) cyclam groups chelating nickel ions (Ni-cyclam) were synthesized by two different approaches. Characterizations by transmission electron microscopy TEM and UV-VIS absorption spectroscopy were performed to monitor the structure and optical properties of the material with regard to the used synthesis methods. The assignment of the experimental UV-VIS absorption spectra is carried out by using the support of suitable numerical simulations based on quantum chemistry DFT codes developed on the modelled (Ni-cyclam) system as free molecule and also constrained in the pores of mesoporous silica matrices.

[en] We have used grazing incidence small angle X-ray scattering (GISAXS) experiments to probe the mesoscopic organization of cetyltrimethyl ammonium bromide (CTAB) templated silica thin films combined to optical interferometry to monitor the macroscopic evolution of these films as a function of relative humidity (RH). The combination of these two experiments permits to address how water can penetrate or quit the silica network during cycling the RH. We report both the fast and the long time responses of these hybrid materials upon cycling the RH. We show that at high RH a hydration layer of one water molecule covers the micelles. Long time response evidences that the silica network remains flexible along the normal to the films for several hours

[en] Mesoporous silica thin films have been prepared through evaporation-induced self-assembly in the presence of non-ionic PEO-PPO-PEO surfactants. We investigated the effects of acid-base post-synthesis treatments on the structure of SBA-15 by immersing the samples into diluted HCl or HNO₃ solutions at ambient temperature and by exposing them to NH₃ atmosphere. The evolution of the 2D hexagonal structure was investigated by X-ray reflectivity (XR) before and after removing the surfactant from the silica matrix. XR curves analyzed were evaluated by the matrix technique to obtain the average electron density of the films, the wall thickness, the electron density of the walls