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Frequency estimation is often the basis of various measurement techniques, among which optical distance measurement stands out. One of the most used techniques is interpolated fast Fourier transform due to its simplicity, combined with good performance. In this work, we study the limits of this technique in the case of real signals, with reference to a particular interferometric technique known as self-mixing interferometry. The aim of this research is the better understanding of frequency estimation performances in real applications, together with guidance on how to improve them in specific optical measurement techniques. An optical rangefinder, based on self-mixing interferometry, has been realized and characterized. The simulation results allow us to explain the limits of the interpolated fast Fourier transform applied to the realized instrument. Finally, a method for overcoming them is proposed by decorrelating the errors between the measurements, which can provide a guideline for the design of frequency-modulated interferometric distance meters. [ABSTRACT FROM AUTHOR]

Malignant melanoma of the sinonasal area is a rare tumor that arises from melanocytes in the nasal mucosa and is more aggressive than the cutaneous type with a poor prognosis. We report a 60-year-old female with the initial chief complaint of nasal cavity fullness, continuous epistaxis, and nasal bone deformity in the past two months. In a primary examination, a black mass was found, and in an excisional biopsy, the pathologist reported sinonasal malignant melanoma, which was confirmed after IHC staining. In spindle cell tumors of the head and neck area, we should be aware of mucosal malignant melanoma as a differential diagnosis. [ABSTRACT FROM AUTHOR]

Background & Objective: Since December 2019 in Wuhan, China there is a new form of pneumonia and after expansion in other countries, World Health Organization (WHO) called it Coronavirus Disease 2019 (COVID-19). Since the clinical laboratory findings have played an important role in the progression of the disease, this study aimed to evaluate the laboratory findings in COVID-19 patients (before vaccination). Methods: In this case-control study that was conducted from February to August 2020; the laboratory test status in 101 positive COVID-19 patients was evaluated and compared with 101 healthy individuals. Results: The results of our study showed that 21% of patients had low WBC, 24.75% low RBC, 37.62%, low Hb, 18.81% with low HCT, 29.7%, low Plt, 41.58% had High PT, 71.29% high CRP, 17.82% high urea, 11.88% high CR, 15.84% high LDH, 10.89% low sodium, 14.75% low potassium (K). The quantitative examination of blood factors showed that lymph%, mixed%, PLT, HCT, Hb, and RBC were higher in the control group than in the case group. While Neu%, WBC, PTT, CRP, UREA, LDH, K in the patient group were higher than in the control group. Conclusion: According to the results of the study, it can be concluded that in the clinical treatment of COVID-19 patients, much attention should be paid to the laboratory indicators to identify and intervene early in critically ill patients. [ABSTRACT FROM AUTHOR]

Background: To gain insight into the pathogenesis and clinical course of COVID-19 from a historical perspective, we reviewed paraclinical diagnostic tools of this disease and prioritized the patients with a more severe form of disease admitted to intensive care units (ICUs). The objective was to better predict the course and severity of the disease by collecting more paraclinical data, specifically by examining the relationship between hematological findings and cytological variation of blood neutrophils and monocytes. Methods: This retrospective study was conducted on 112 patients with confirmed COVID-19 admitted to Imam Hossein Hospital (Tehran, Iran) from August to September 2020. Peripheral blood smears of these patients were differentiated according to several cytological variations of neutrophils and monocytes, and the correlation to the severity of the disease was specified. Results: The mean percentages of degenerated monocytes, degenerated granulocytes, and spiky biky neutrophils were significantly different among critical and non-critical patients (P<0.05). Degenerated monocytes and granulocytes were higher in critical patients as opposed to spiky biky neutrophils, which were higher among non-critical ones. Comparing the peripheral blood smears of COVID-19 patients (regarding pulmonary involvement in chest computed tomography [CT] scans [subtle, mild, moderate, and severe groups]), the twisted form of neutrophils was significantly higher in the subtle group than in the mild and moderate groups (P=0.003). Conclusion: Different cytological morphologies of neutrophils and monocytes, including degenerated monocytes, degenerated granulocytes, and spiky biky and twisted neutrophils, could help to predict the course and severity of the disease. [ABSTRACT FROM AUTHOR]

Background & Objective: Mucormycosis (also called black fungus) is an opportunistic serious fungal infection caused by mucormycetes. It can occur in diabetes mellitus patients and other immunosuppressive conditions with recent predisposing factors such as maxillofacial surgery and corticosteroid usage. Methods: In this study, 14 patients were referred to the otorhinolaryngology or ophthalmology ward of Shafa Hospital (Kerman, Iran) with primary symptoms of nasal fullness and facial nerve dysfunction; they were admitted to the hospital to rule out the fungal infection. An endoscopic biopsy was taken from facial sinuses or orbit, and a microscopic evaluation was performed using hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining methods to rule out mucormycosis. Results: In the histopathological examination, broad-based nonseptate branching fungal hyphae were found in nasal sinuses through the endoscopic biopsy. Most of the patients had diabetes mellitus with a primary symptom of facial nerve palsy; also, most of them received corticosteroids (intravenous [IV] or intramuscular [IM] injection). All patients have recently been infected with COVID-19 (less than 1 month ago). Conclusion: COVID-19 infection might be a predisposing factor for many opportunistic infections, such as fungal elements); thus, the physician should be aware of the dosage and duration of corticosteroid therapy to prevent the development of these infections. [ABSTRACT FROM AUTHOR]

Optical rangefinders based on Self-Mixing Interferometry are widely described in literature, but not yet on the market as commercial instruments. The main reason is that it is relatively easy to propose new elaboration techniques and get results in controlled conditions, while it is very difficult to develop a reliable instrument. In this paper, we propose a laser distance sensor with improved reliability, realized through a wavelength modulation at a different frequency, able to decorrelate single measurement errors and obtain improvement by averages. A dedicated software is implemented to automatically calculate the modulation pre-emphasis, needed to linearize the wavelength modulation. Finally, data selection algorithms allow to overcome signal fading problems due to the speckle effect. A prototype demonstrates the approach with about 0.1 mm accuracy up to 2 m of distance at 200 measurements per second. [ABSTRACT FROM AUTHOR]

The presence of liquid slightly changes the local properties of submerged transmission line. A dedicated sensor is presented in this paper to estimate the level of liquid, through two different determinations: measurement of the overall capacitance of a bi-wires and time of flight estimation of electromagnetic radiation. Since two measurement methods are physically independent, the proposed sensor has an intrinsic redundancy. The level of liquid is measured through phase shift: the signals are sampled at a sufficiently high frequency and then phase differences is evaluated by calculating the coefficients of the digital Fourier transform. Both measurements are performed directly in baseband without requiring frequency conversions. In contrast with typical TDR system where the end of the cable is open or short-circuited, the bi-wires fold and return to the measurement electronics. The characterization of the proposed sensor is determined experimentally for water and diesel fuel, in good agreement with simulation results. As results show, both phase-shifting measurements are linear with the liquid level, providing a resolution in the order of 0.1 mm through a compact and low-cost realization. [ABSTRACT FROM AUTHOR]

Introduction: Probiotics, including lactobacilli, have immunomodulatory activities with promising effects on inflammatory diseases. In this study, we evaluate the effect of Enterococcus durans (Edu) and three various strains of lactobacilli (Lacto-mix), including L. rhamnosus, L. casei, and L. plantarum, to prevent Experimental Autoimmune Encephalomyelitis (EAE) features Methods: C57BL/6 female mice were inoculated with Myelin Oigodendrocyte Glycoprotein (MOG35-55) in CFA (complete Freund's adjuvant) to induce EAE. Five groups (n=6 in each group) of animals received saline or probiotics by oral gavage with 200 µL of lactobacilli (1.5×108 CFU/mL) for 2 weeks before the immunization and during the test for one month. Results: Histopathological studies showed an increase in infiltration of inflammatory cells and destruction of the myelin membrane in the EAE group but a decrease in inflammatory cells in the probiotic-treated animals. Pro-inflammatory cytokines (Interleukin [IL]-17 and Interferon [IFN]-1) concentration in the supernatant of the brain and spinal cord tissues showed a significant increase in the EAE compared with the normal saline group (P<0.01). While in the spinal cord tissue, there was a decrease in IL-17 in those animals treated with the Lactomix and Edu + Lacto-mix (P<0.01) and a significant decrease in IFN-1 in those animals that received Edu (P<0.05). Western blot analysis of matrix metalloproteinase-9 and myelin basic protein showed a decrease and increase in treatment and EAE groups, respectively, compared to the normal control group. Conclusion: Our data suggest that probiotic Enterococcus durans and Lacto-mix prevents EAE, but further studies are needed to clarify the exact mechanisms and their application in preclinical and clinical trials. [ABSTRACT FROM AUTHOR]

In this research, aluminum (Al) thin films were deposited on SiO2/Si substrates using RF magnetron sputtering technique for analyzing the influence of RF sputtering power on microstructural surface morphologies. Different sputtering RF powers (100–400 W) were employed to form Al thin films. The characteristics of deposited Al thin films are investigated using X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier-transforms infrared (FTIR) spectroscopy. The X-ray diffraction (XRD) results demonstrate that the deposited films in low sputtering power have amorphous nature. By increasing the sputtering power, crystallization is observed. AFM analysis results show that the RF power of 300 W is the optimum sputtering power to grow the smoothest Al thin films. FTIR results show that the varying RF power affect the chemical structure of the deposited films. The SEM results show that by increasing the sputtering power leads to the formation of isolated texture on the surface of substrate. In conclusion, RF power has a significant impact on the properties of deposited films, particularly crystallization and shape. [ABSTRACT FROM AUTHOR]

Change in density will cause errors in measurement for indirect-based level sensing approaches, such as capacitive sensors. In addition, there is growing attention in measuring density accurately not only in laboratory conditions but also in a real-time dynamic environment. To address the above-mentioned issues, an independent instrument based on differential pressure sensors is proposed in this article. Synchronous detection is used to detect the desired signal by calculating the coefficients of the digital Fourier transform. The characterization of the sensor is experimentally determined under a steady-state condition, where a linear response is observed. The thermal behavior of the proposed sensor is studied and compensated using the polynomial fitting technique. Evaluating the uncertainty due to reference values, linearity, and repeatability, the obtained results show a combined uncertainty lower than 7.5 (mg/cm3), mainly limited by observed asymmetric hysteresis at higher temperatures. [ABSTRACT FROM AUTHOR]

Silver doped Indium sulphide thin films with different [Ag/In] molar ratio concentrations (0, 0.9, 1.0, 1.1) were deposited on glass substrates using chemical bath deposition method. The structural, morphological, optical and electrical properties are characterized using XRD, EDAX, SEM, AFM, spectrophotometer and Hall measurement system, respectively. Kramers-Kronig method was used to obtain optical constants of the films. It is found that Ag can change physical properties of Indium sulfide thin films, depending on the Ag concentration. XRD results show the incorporation of Ag concentration did not change the structure of In2S3. Doped films had rough surfaces. As the [Ag/In] molar ratio increased, conductivity increases and optical direct band gap energy decreases from 2.75 to 2.38 eV. [ABSTRACT FROM AUTHOR]

To achieve a reliable and accurate liquid-level detection, a differential pressure-based instrument is proposed in this article. The phase-sensitive demodulation of the signal is performed by the discrete Fourier transform (DFT) through a microcontroller. A good linearity in both ac and dc measurements has been observed. AC-based-level sensing demonstrated reliable and robust-level detection compared with dc, in both steady state conditions and while experiencing turbulence on the surface. In addition, thermal behavior of the proposed instrument is characterized and compensated, in order to evaluate its uncertainty as a liquid-level sensor. The obtained results show a combined uncertainty lower than 1 mm, which is mainly limited by sloshing conditions. [ABSTRACT FROM AUTHOR]

An aqueous colloidal solution was prepared at 80 °C and pH = 9 from suitable chemical compounds to produce zinc oxide (ZnO) crystals and thin films. The ZnO crystals were grown in the colloidal solution under special conditions. Their micrographs showed ZnO rods with hexagonal structure. The number of the rods, increased over time. The ZnO thin films were produced on glass substrates in the same colloidal solution using the chemical bath deposition (CBD) method in different deposition times. The produced films were post-annealed for about one hour at 400 °C. Crystalline structure, phase transitions and nanostructure of the films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). ZnO wurtzite structure was dominant, and by increasing the deposition time, the films became more crystalline. Nanostructure of the films changed from rod to wire and transformed into pyramid-like structures. Also, morphology of the films changed and re-nucleation ocurred. Optical reflectance was measured in the wavelength of 300 nm to 800 nm with a spectrophotometer. Other optical properties and optical band gaps were calculated using Kramers-Kronig relation on reflectivity curves. Second harmonic generation was calculated by Z-scan technique. Nonlinear refraction and real part of susceptibilities were obtained. Both positive and negative nonlinear refractions appeared in the ZnO films. It is important for the use in optoelectronic devices. Electronic properties were assessed by the full potential linearized augmented plane wave (FP-LAPW) method, within density functional theory (DFT). In this approach, the generalized gradient approximation (GGA) was used for the exchange-correlation potential calculation. The band gap structure and density of states were calculated. [ABSTRACT FROM AUTHOR]

A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured. [ABSTRACT FROM AUTHOR]