RESUMO
The shielding effectiveness (SE) against the electromagnetic interference (EMI) of polyvinyl alcohol/multiwall carbon nanotubes (PVA/MWCNTs) composite nanofibers is characteristic of higher absorptivity of the radiation that enhances with the increasing concentration of MWCNTs content in these composites. However, by enriching the content of conductive fillers (MWCNTs), the conductivity of the composites is also stirred up. Concomitantly, the conductivity of these composites contributes toward the reflectivity of the EM radiation from them. Certain applications of the EMI shielding material require a lower level of reflectivity of the EM radiation. This study intends to see how SE of the PVA/MWCNTs composite nanofibers is affected vis-a-vis their conductivity for S-band radiation. Samples of nanofibers, with (5, 10, 15, and 20) wt % of MWCNTs loading in 10 wt % of PVA solution, were prepared through electrospinning and studied for their electrical conductivity and EMI SE. It is observed that by increasing the content of MWCNTs in PVA solution from 5 to 20 wt % the conductivity of the composites tends to increase from 21 to 866 times that of PVA, while the SE increases from 10 db to 25 db over the S-band range of frequencies.
RESUMO
Gas-forming bacteria like Staphylococcus aureus (SA), along with the worrisome infections it causes, can lead to a fairly overlooked but lethal complication, called emphysematous osteomyelitis (EO). It is a condition characterized by the infection of bones complicated by the presence of gas-forming organisms. Here, we present a 50-year-old woman with insulin-dependent type 2 diabetes, who presented with cough, high-grade fevers, rigors, chills, and back pain from the last seven days. Laboratory tests revealed elevated inflammatory markers and a hyperosmolar hyperglycemic state. Sputum smear and blood cultures both reported the presence of SA. The presence of air foci in the third lumbar spine vertebra (L3) and the surrounding soft tissue was confirmed by computed tomography (CT). The posterior elements were spared, and the vertebral height and intervertebral disc were preserved. The extent of the damage done to the bone was analyzed by magnetic resonance imaging (MRI). The findings showed transverse relaxation time (T2) and short tau inversion recovery (STIR) sequences, consistent with the diagnosis of EO. She was put on strict glucose monitoring and a combination of intravenous antibiotics for three weeks followed by two weeks of oral therapy. Her symptoms improved with conservative management and reported no recurrence of any symptom of such type ever since.
