Extraintestinal Seeding of Salmonella enterica Serotype Typhi,Pakistan

We evaluated Salmonella enterica serotype Typhi strains isolated from all body sites in Pakistan during 2013–2018. Despite an increase in overall number of localized, extensively drug-resistant Salmonella Typhi in organ infections during 2018, there was no increase in the proportion of such isolates in comparison with non–extensively drug-resistant isolates.     

Molecular basis of non-alcoholic fatty liver disease and metabolic syndrome in a subset of South Asians

International Journal of Diabetes in Developing Countries - Metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD) are emerging threats in Pakistan. The prevalence of MetS is...     

Size-dependent magnetic and magnetothermal properties of gadolinium silicide nanoparticles

Gadolinium silicide (Gd₅Si₄) nanoparticles are an interesting class of materials due to their high magnetization, low Curie temperature, low toxicity in biological environments and their multifunctional properties. We report the magnetic and magnetothermal properties of gadolinium silicide (Gd₅Si₄) nanoparticles prepared by surfactant-assisted ball milling of arc melted bulk ingots of the compound. Using different milling times and speeds, a wide range of crystallite sizes (13–43 nm) could be produced and a reduction in Curie temperature (T_C) from 340 K to 317 K was achieved, making these nanoparticles suitable for self-controlled magnetic hyperthermia applications. The magnetothermal effect was measured in applied AC magnetic fields of amplitude 164–239 Oe and frequencies 163–519 kHz. All particles showed magnetic heating with a strong dependence of the specific absorption rate (SAR) on the average crystallite size. The highest SAR of 3.7 W g⁻¹ was measured for 43 nm sized nanoparticles of Gd₅Si₄. The high SAR and low T_C, (within the therapeutic range for magnetothermal therapy) makes the Gd₅Si₄ behave like self-regulating heat switches that would be suitable for self-controlled magnetic hyperthermia applications after biocompatibility and cytotoxicity tests.

Gadolinium silicide (Gd₅Si₄) nanoparticles prepared by surfactant-assisted ball milling exhibit a size-dependent reduction in magnetic ordering temperature and a high magnetothermal effect making them suitable for magnetic hyperthermia applications.     

Molecularly imprinted polymeric coatings for sensitive and selective gravimetric detection of artemether

Monitoring antimalarial drugs is necessary for clinical assays, human health, and routine quality control practices in pharmaceutical industries. Herein, we present the development of sensor coatings based on molecularly imprinted polymers (MIPs) combined with quartz crystal microbalance (QCM) for sensitive and selective gravimetric detection of an antimalarial drug: artemether. The MIP coatings are synthesized by using artemether as the template in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) matrix. Artemether-MIP and the non-imprinted polymer (NIP) control or reference layers are deposited on 10 MHz dual-electrode QCM by spin coating (187 ± 9 nm layer thickness after optimization). The coatings are characterized by FTIR spectroscopy and atomic force microscopy that reveal marked differences among the MIP and NIP. The MIP-QCM sensor exhibits high sensitivity (0.51 Hz ppm⁻¹) with sub-10 ppm detection and quantification limits. The MIP-QCM sensor also exhibits a 6-fold higher sensitivity compared to the NIP-QCM, and a dynamic working range of 30–100 ppm. The response time of MIP-QCM devices for a single cycle of analyte adsorption, signal saturation, and MIP regeneration is less than 2.5 min. The sensor also demonstrates selectivity factors of artemether-MIP of 2.2 and 4.1 compared to artemisinin and lumefantrine, respectively. Reversibility tests reveal less than 5% variation in sensor responses over three cycles of measurements at each tested concentration. The MIP-QCM showed lower detection limits than conventional HPLC-UV, and faster response time compared to HPLC-UV and liquid chromatography-mass spectrometry (LC-MS).

Chemical structures of the antimalarial drugs: artemisinin, artemether (a methyl ether derivative of artemisinin), and lumefantrine.