Dengue Fever: A Continuous Threat

Dengue fever is a vector borne disease and is caused by DEN Virus. This virus has four different serotypes. The vectors are two mosquitoes known as Aedesaegypti (the yellow fever mosquito) and Aedesalbopictus(the Asian tiger mosquito).  First case of dengue fever was reported back in 1994 in Karachi. A complete outbreak of this epidemic shook the whole nation in 2012. Uptill now, Lahore a city full of culture, witnessed about 16,580 confirmed cases and 257 deaths. About 5000 confirmed cases with 60 deaths were reported from the rest of the provinces. Under guidelines of WHO, Government has made efforts to combat this epidemic. Although the overall efforts have minimized the outbreak on controllable levels but dengue fever is a continuous threat. Since no permanent cure is available, the transmission of DEN virus is controlled indirectly. So the prime focus is to control mosquito population and decrease the possible hot spots i.e. Mosquito breeding sites in human habitations. Every year, the country witnesses monsoon season which brings vast areas full of clear standing waters providing breeding sites for mosquitoes which ultimately leads to increased number of patients suffering from dengue fever. Efforts have been made to fight against dengue including formation of dengue wards in hospitals, vector surveillance, community education, reactive vector control etc. A study has shown prevalence of four mosquito genera in Pakistan including Aedes, Culex, Armigeresand Anopheles. All of the above mentioned genera are associated with disease transmissions as they are the vectors of different viruses and parasites. It is the need of hour to do a collaborative effort stressing the community mobilization and management in war against dengue.

Ab-Initio Investigation of Pristine and Intrinsic Vacancy Defect-Containing A3sno and A3pbo A: Ca, Sr and Ba Inverse Perovskites

The A3SnO and A3PbO (A: Ca, Sr and Ba) inverse perovskite oxides have gained immense research attention as they exhibit physical properties suitable for thermoelectric, superconducting and magnetic devices. The emergence of stoichiometry dependent stable ferromagnetism in these inverse perovskites has recently made these materials potential candidates for utilization in spintronic and quantum computing devices. In the present work, DFT based first principles total energy calculations have been employed using the full-potential linearized augmented plane-wave method to explore the electronic, magnetic and thermodynamic properties of pristine and intrinsic vacancy defect containing A3SnO and A3PbO (A: Ca, Sr and Ba) compounds. The electronic structures of these compounds are computed with the inclusion of spin orbit coupling interactions which plays an important role in topological nature of these compounds. Furthermore, the spin-polarization calculations have been carried out to investigate the impact of vacancy defects on magnetic and electronic properties of these inverse perovskites. The thermodynamic stability analysis indicated that these materials can be synthesized under Ca/Sr/Ba rich and Sn/Pb intermediate-rich conditions. Moreover, the defect formation energies revealed that Ca/Ba/Sr vacancies are the most stable form of vacancy defect under oxidation (O-rich) conditions, while O and Sn/Pb vacancies are found to have stableunder reduction (O-poor) and Sn/Pb-poor conditions, respectively. Our calculations reveal that charge neutral Sn or O vacancies can give rise to stable ferromagnetism in non-stoichiometric A3SnO and A3PbO (A: Ca, Sr and Ba) compounds.