Comparison of chest HRCT severity score in PCR positive and PCR negative clinically suspected COVID-19 Patients

Background: The limitations and false-negative results of Real-time Polymerase chain reaction (RT PCR) in diagnosing COVID-19 infection demand the need for imaging modalities such as chest HRCT to improve the diagnostic accuracy andassess the severity of the infection. Objectives: The study aimed to compare the chest HRCT severity scores in RT-PCR positive and negative cases of COVID-19. Methods: This cross-sectional study included 50 clinically suspected COVID-19 patients. Chest HRCT and PCR testing of all 50 patients were done and the chest HRCT severity scores for each lung and bronchopulmonary segments were compared in patients with positive and negative PCR results. Chi-square and Mann Whitney U test were used to assess differences among study variables. Results: Chest HRCT severity score was more in PCR negative patients than in those with PCR positive results . However, the difference was not significant (p=0.11). There was a significant association in severity scores of the anterior basal segment of the left lung (p=0.022) and posterior segment upper lobe of right lung (p=0.035) with PCR results. This association was insignificantfor other bronchopulmonary segments (p>0.05). Conclusion: CR negativity does not rule out infection in clinically suspected COVID-19 patients. The use of chest HRCT helps to determine the extent of lung damage in clinically suspected patients irrespective of PCR results. Guidelines that consider clinical symptoms, chest HRCT severity score and PCR results for a confirmed diagnosis of COVID-19 in suspected patientsare needed. Keywords: Chest High resolution computed tomography (HRCT); COVID-19; Polymerase Chain Reaction (PCR)

Formulation, characterization and optimization of nebivolol-loaded sustained release lipospheres

Purpose: To formulate, characterize and optimize nebivolol-loaded sustained release lipospheres (LPs) using beeswax (BW) as the drug carrier.Methods: Nebivolol-loaded LPs were formulated using solvent evaporation technique (SET) and characterized. The impact of independent variables on responses such as percentage yield (PY), entrapment efficiency (EE) and drug release after 12 h (DR12) was assessed using central composite design (CCD). Numerical and graphical optimization techniques were also used to evaluate outcomes of the measured responses.Results: Twenty micron-sized (20 - 100 μm), smooth spherical LPs with good rheological properties were produced. The yield ranged from 33 (F10) to 81 % (F6), while EE ranged from 32 (F4 and F9) to 69 % (F6). The results of rheological evaluation revealed angle of repose > 24 o, Hausner’s ratio > 1.5, and Carr’s index ranging from 13 to 19 %. Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and x-ray diffraction (XRD) revealed nebivolol and BW compatibility, and the absence of possible interactions between formulation components. Duration of nebivolol release was strongly associated with BW concentration and formulation F15 showed minimum drug release (46%). Drug release was significantly higher in formulations with similar BW concentrations and low Tween-20 (T-20) concentrations (F1 and F11) than in formulations with high T-20 concentrations (F2, p < 0.05). The zeta potential of deflocculated LPs ranged from +15 to +35 mV. Nebivolol release (46 - 85 %) at pH 6.8 was significantly affected by BW concentration and it followed zero order model.Conclusion: The results obtained in this study have shown that BW is a suitable material for producing an effective sustained release formulation. The mechanism of drug release in nebivolol- loaded LPs is diffusion accompanied by erosion.Keywords: Lipospheres, Nebivolol, Beeswax, Formulation, Central composite desig

Sustained release biodegradable solid lipid microparticles: Formulation, evaluation and statistical optimization by response surface methodology

For preparing nebivolol loaded solid lipid microparticles (SLMs) by the solvent evaporation microencapsulation process from carnauba wax and glyceryl monostearate, central composite design was used to study the impact of independent variables on yield (Y1), entrapment efficiency (Y2) and drug release (Y3). SLMs having a 10–40 µm size range, with good rheological behavior and spherical smooth surfaces, were produced. Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry pointed to compatibility between formulation components and the zeta-potential study confirmed better stability due to the presence of negative charge (–20 to –40 mV). The obtained outcomes for Y1 (29–86 %), Y2 (45–83 %) and Y3 (49–86 %) were analyzed by polynomial equations and the suggested quadratic model were validated. Nebivolol release from SLMs at pH 1.2 and 6.8 was significantly (p ˂ 0.05) affected by lipid concentration. The release mechanism followed Higuchi and zero order models, while n ˃ 0.85 value (Korsmeyer-Peppas) suggested slow erosion along with diffusion. The optimized SLMs have the potential to improve nebivolol oral bioavailability

DESIGN AND OPTIMIZATION OF THIN FILM MULTILAYER STRUCTURES FOR ACOUSTO-OPTIC DEVICES

Wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is a popular technique

Green vegetation: a promising source of color dyes

The present study aimed for the extraction of color dyes from different sources, such as Brassica oleracea, Brassica campestris, Citrus limon, Citrus limetta, Tagetes erecta, Spinacea oleracea, Beta vulgaris, Rosa indica and Curcuma longa. The leftovers of such plants were mainly used for color dye extraction and their confirmation using spectrophotometric analysis. The specific color pigments like carotenoids, anthocyanin, chlorophyll and betanin were found to be the main coloring agents that impart specific color to the samples. Among all these samples, the maximum yield was obtained from C. limetta aqueous peel extract, and among all the temperatures employed room temperature was found out to be the most suitable temperature for the stability of color extracts. The extracted colors were utilized in candy making and sugar syrup making and were also used for coloring various foods stuffs. Moreover, the extracted color dyes were applied for dyeing purposes on cotton cloth with alum showing better and more enhancing color fastness results than the lime

FEM Analysis of Various Multilayer Structures for CMOS Compatible Wearable Acousto-Optic Devices

Lately, wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is seen to be a popular technique. This paper undertakes the study of different multilayer structures that can be fabricated for realizing an acousto-optic device, the objective being to obtain a high acousto-optic figure of merit (AOFM). By varying the thicknesses of the layers of these materials, several properties are discussed. The study shows that the multilayer thin film structure-based devices can give a high value of electromechanical coupling coefficient (k2) and a high AOFM as compared to the bulk piezoelectric/optical materials. The study is conducted to find the optimal normalised thickness of the multilayer structures with a material possessing the best optical and piezoelectric properties for fabricating acousto-optic devices. Based on simulations and studies of SAW propagation characteristics such as the electromechanical coupling coefficient (k2) and phase velocity (v), the acousto-optic figure of merit is calculated. The maximum value of the acousto-optic figure of merit achieved is higher than the AOFM of all the individual materials used in these layer structures. The suggested SAW device has potential application in wearable and small footprint acousto-optic devices and gives better results than those made with bulk piezoelectric materials

Design and Optimization of High Performance P3HT: PCBM Polymer Solar Cell Using P3HT Buffer Layer

In this paper, a novel structure of multilayer organic photovoltaic cell has been designed and simulated. The integration of Poly(3-hexylthiophene-2,5-diyl) (P3HT) buffer layer and Poly(9,9-bis(3’-(N,N-dimethyl) N- ethylammoinium propyl-2,7-fluorene)-alt-2,7-(9,9 dioctyl fluorene)) dibromide (PFN:BR) electron transport layer (ETL) in the proposed solar cell has improved the performance significantly. The various performance measuring parameters like power conversion efficiency (PCE), short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), quantum efficiency (QE) have improved significantly. Furthermore, the effect of different layer thickness, the density of traps $N_{t}$ and temperature on the proposed solar cell has been studied and the optimum value has been obtained. It has been observed that after optimizing the different parameters of the proposed structure, the performance measuring parameters shows an improvement of 14%, 33.3%, 200% and 300% in Voc FF, Jsc and PCE respectively over the reported organic solar cells. Further, a QE of about 90% is achieved in the proposed structure