Correlation among the structural, electric and magnetic properties of Al3+ substituted Ni-Zn-Co ferrites.

This study explored the structural, electrical, and magnetic properties of diamagnetic aluminium (Al3+) substituted nickel-zinc-cobalt (Ni-Zn-Co) mixed spinel ferrites, though the research on this area is in the infancy stage. Single-phase cubic spinel structures with the Fd3̄m space group of the synthesized Ni0.4Zn0.35Co0.25Fe(2-x)Al x O4 (0 ≤ x ≤ 0.12) ferrite samples were confirmed by X-ray diffraction (XRD) analysis. The average particle size ranged from 0.67 to 0.39 µm. Selected area electron diffraction (SAED) patterns were indexed according to the space group Fd3m, representing the particle's crystallinity. The optical band gaps ranged from 4.784 eV to 4.766 eV. Frequency-dependent dielectric constants and ac conductivity measurement suggested that the prepared ferrites were highly resistive. Relaxation times were reduced to a low value from 45.45 µs to 1.54 µs with the composition x. The Curie temperatures (T c) were 615-623 K for all samples. Real part permeabilities (µ /) were relatively stable up to an extended frequency range of 106 Hz with relative quality factors (RQF) of around 103. Tuning of the properties indicates that the fabricated ferrites may be promising for high-frequency electronic devices.

Efficacy and Safety of the Awake Prone Positioning in Patients with COVID-19 Related Respiratory Distress: A Scoping Review.

Prone positioning (PP) is becoming an important treatment modality for the management of COVID-19 related respiratory distress syndrome. The aim of this scoping review was to evaluate effectiveness and safety of awake PP in non-intubated patients with COVID-19 related acute respiratory distress at different care settings. The study was conducted during December 1, 2019 to August 30, 2020 using health science electronic databases and grey literature. A PRISMA flow diagram was used and finally 06 studies with 187 patients were included for review. Male patients were predominating with the mean age of approximately 55 years. Oxygenation was improved in 79.14% patients. One hundred fifty seven (83.95%) patients with COVID-19-related hypoxemic respiratory distress tolerated the procedure. Intubations required 25.41% of the patients or mechanical ventilation and 6(3.2%) patients expired. Number of patients in the reported studies could tolerate more than 3 hours of PP without a major side effect. Awake proning improved oxygenation of the patients suffering from COVID-19 related respiratory hypoxia in different care settings. Early instituted prone positioning may be an effective alternative method of treating COVID-19 related respiratory distress. Patient compliance and small size cohort studies are the limitations of this review. Multicenter controlled studies are warranted before conclusions are made about safety and the settings.

Evaluation of sulbactam and colistin/sulbactam efficacy against multiple resistant Acinetobacter baumannii blood isolates.

PURPOSE: We aimed to compare the results of the BD Phoenix (TM) M50 ID/AST system and the gold standard broth microdilution method. We also evaluated the potential of a new therapeutic combination (colistin/sulbactam) for colistin resistance among Acinetobacter baumanni strains. METHODS: Growth in blood samples was detected with the BACTEC (BD Becton Dickinson, ABD) continuous monitoring blood culture system. Strains were identified by Phoenix (BD Phoenix™ M50, ABD) automated bacterial identification system and antimicrobial susceptibility results were obtained. A total of 92 A. baumannii complex isolates showing resistance to at least three antibiotic classes were included in the study. Colistin susceptibility results (both susceptible and resistant strains) detected by the Phoenix device were confirmed by the reference method, the liquid microdilution method. The concentration index (FIC) was used to determine the efficacy of fractional inhibitor drug combinations, the efficacy of colistin/sulbactam combination against 50 multiresistant A. baumannii complex strains was investigated using the checkerboard method. RESULTS: 10 (10.9%) of 92 isolates were resistant to colistin and 80 (86.9%) to sulbactam. With the automation system, only 2 of 10 isolates were found resistant to colistin, while 8 isolates were susceptible. For this reason, the very major error rate of the Phoenix M50 automatic system among resistant isolates was determined as 8/10. It was determined that 6 (12%) of the colistin/sulbactam combination had a synergistic effect and 44 (88%) had an additive interaction. No antagonistic interaction was detected with the colistin-sulbactam combination in this study. CONCLUSION: A. baumannii strains should be confirmed by the broth microdilution method, which is the reference method, against the MIC results detected by automated systems. It was concluded that the use of colistin alone should be avoided in the treatment of A. baumannii infections.

Investigation of Morphological, Optical, and Dielectric Properties of RF Sputtered WOx Thin Films for Optoelectronic Applications.

Tungsten oxide (WOx) thin films were synthesized through the RF magnetron sputtering method by varying the sputtering power from 30 W to 80 W. Different investigations have been conducted to evaluate the variation in different morphological, optical, and dielectric properties with the sputtering power and prove the possibility of using WOx in optoelectronic applications. An Energy Dispersive X-ray (EDX), stylus profilometer, and atomic force microscope (AFM) have been used to investigate the dependency of morphological properties on sputtering power. Transmittance, absorbance, and reflectance of the films, investigated by Ultraviolet-Visible (UV-Vis) spectroscopy, have allowed for further determination of some necessary parameters, such as absorption coefficient, penetration depth, optical band energy gap, refractive index, extinction coefficient, dielectric parameters, a few types of loss parameters, etc. Variations in these parameters with the incident light spectrum have been closely analyzed. Some important parameters such as transmittance (above 80%), optical band energy gap (~3.7 eV), and refractive index (~2) ensure that as-grown WOx films can be used in some optoelectronic applications, mainly in photovoltaic research. Furthermore, strong dependencies of all evaluated parameters on the sputtering power were found, which are to be of great use for developing the films with the required properties.

Extraction, optical properties, and aging studies of natural pigments of various flower plants.

In this paper, we reported the extraction process of five different flowering plants utilizing different dye extraction methods and solvents (ethanol and water) to choose the best dye removal process. The FTIR spectra revealed the presence of several clear functional groups for all five natural dyes. The analytical studies such as UV spectroscopy, column chromatography, and vacuum evaporation were performed to isolate the dyes from their solutions. The UV-Vis studies on the pigments of flower extracts indicated broad absorption peaks in the visible region including clear bandgaps. Among the studied pigments, Alternanthera ficoidea showed the lowest direct bandgap of 1.69 eV and an Urbach energy value of 6.33 meV. The dye extraction yield rate improvement was extended from 11.7 to 24.7% (water solvent) and 11.3-32.4% (ethanol solvent). Throughout the studies, it was observed that ethanol produced a better extraction for organic dyes than water as a solvent. Aging studies revealed that all the dyes at the room temperature showed better stability with minor changes in the observed optical parameters in oxygen-rich conditions; however, these parameters have shown significant variations at a 60 °C temperature.

Bi0.9Ho0.1FeO3/TiO2 Composite Thin Films: Synthesis and Study of Optical, Electrical and Magnetic Properties.

A visible light active Bi0.9Ho0.1FeO3 nanoparticles/TiO2 composite thin films with different mol.% of Bi0.9Ho0.1FeO3 were successfully prepared via non-aqueous sol-gel method. The incorporation of 5, 10 and 20 mol.% Bi0.9Ho0.1FeO3 nanoparticles in the precursor solution of TiO2 brings modifications in the functional properties of the composite thin films. XPS analysis indicates that interdiffusion of Fe3+, Ho3+, Bi3+/Ti4+ ions through the interfaces between Bi0.9Ho0.1FeO3 nanoparticles and TiO2 matrix reduces the concentration of Ti3+ ions. X-ray diffraction analysis affirms that TiO2 and Bi0.9Ho0.1FeO3 retain anatase and orthorhombic phase respectively in composite films. The composite thin film containing 20 mol.% Bi0.9Ho0.1FeO3 nanoparticles exhibits the most prominent absorption phenomenon in visible region and has significantly reduced indirect band gap of 2.46 eV compared to that of pure TiO2 (3.4 eV). Hall effect measurements confirm that the resistivity of composite film increases by ∼2.33 orders of magnitude and its carrier concentration decreases by 1.8 orders of magnitude at 5 mol.% Bi0.9Ho0.1FeO3 nanoparticles addition compared to those of pure TiO2 film. Moreover, the pure film exhibits diamagnetism, whereas the composite films have both large ferromagnetic and small diamagnetic components. The findings in this research justify that the composite film can be a potential candidate for making improved photocatalyst, resistors and spintronic devices.