139 results match your criteria: "Institute of Atomic Physics and Spectroscopy[Affiliation]"

A practical assessment of the general health and microvascular function of the palm muscle, abductor pollicis brevis (APB), is important for the diagnosis of different conditions. In this study, we have developed a protocol and a probe to study microvascular blood flow using near-infrared diffuse correlation spectroscopy (DCS) in APB during and after thumb abduction at 55% of maximum voluntary contraction (MVC). Near-infrared time resolved spectroscopy (TRS) was also used to characterize the baseline optical and hemodynamic properties.

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Article Synopsis
  • Melanoma is the deadliest form of skin cancer, while seborrheic keratosis (SK) is a common benign skin lesion that can look like melanoma.
  • Researchers used a multispectral imaging device that utilizes autofluorescence and reflectance to analyze images of these skin lesions and found that SK had higher intensity values compared to melanoma.
  • They developed an SK index to help differentiate between the two, achieving 91.9% sensitivity but only 57% specificity, suggesting this imaging method could aid general physicians in screening for skin lesions in practice.
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Sonoporation is the process of cell membrane permeabilization, due to exposure to ultrasounds. There is a lack of consensus concerning the mechanisms of sonoporation: Understanding the mechanisms of sonoporation refines the choice of the ultrasonic parameters to be applied on the cells. Cells' classical exposure systems to ultrasounds have several drawbacks, like the immersion of the cells in large volumes of liquid, the nonhomogeneous acoustic pressure in the large sample, and thus, the necessity for magnetic stirring to somehow homogenize the exposure of the cells.

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Affinity Sensors for the Diagnosis of COVID-19.

Micromachines (Basel)

April 2021

NanoTechnas-Center of Nanotechnology and Materials Science, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko str. 24, 03225 Vilnius, Lithuania.

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required.

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The biodegradable metals, including magnesium (Mg), are a convenient alternative to permanent metals but fast uncontrolled corrosion limited wide clinical application. Formation of a barrier coating on Mg alloys could be a successful strategy for the production of a stable external layer that prevents fast corrosion. Our research was aimed to develop an Mg stable oxide coating using plasma electrolytic oxidation (PEO) in silicate-based solutions.

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From Microorganism-Based Amperometric Biosensors towards Microbial Fuel Cells.

Sensors (Basel)

April 2021

NanoTechnas-Center of Nanotechnology and Material Science, Faculty of Chemistry and Geosciences, Vilnius University, LT-03225 Vilnius, Lithuania.

This review focuses on the overview of microbial amperometric biosensors and microbial biofuel cells (MFC) and shows how very similar principles are applied for the design of both types of these bioelectronics-based devices. Most microorganism-based amperometric biosensors show poor specificity, but this drawback can be exploited in the design of microbial biofuel cells because this enables them to consume wider range of chemical fuels. The efficiency of the charge transfer is among the most challenging and critical issues during the development of any kind of biofuel cell.

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We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator.

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In this study, an optical contactless laser speckle imaging technique for the early identification of bacterial colony-forming units was tested. The aim of this work is to compare the laser speckle imaging method for the early assessment of microbial activity with standard visual inspection under white light illumination. In presented research, the growth of bacterial colonies on the solid medium was observed and analyzed.

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Evaluation of Erythema Severity in Dermatoscopic Images of Canine Skin: Erythema Index Assessment and Image Sampling Reliability.

Sensors (Basel)

February 2021

Department of Clinical Sciences, College of Veterinary Medicine, NC State University, 1060 William Moore Dr., Raleigh, NC 27607, USA.

The regular monitoring of erythema, one of the most important skin lesions in atopic (allergic) dogs, is essential for successful anti-allergic therapy. The smartphone-based dermatoscopy enables a convenient way to acquire quality images of erythematous skin. However, the image sampling to evaluate erythema severity is still done manually, introducing result variability.

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Remote Photoplethysmography for Evaluation of Cutaneous Sensory Nerve Fiber Function.

Sensors (Basel)

February 2021

Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas St. 3, LV-1004 Riga, Latvia.

About 2% of the world's population suffers from small nerve fiber dysfunction, neuropathy, which can result in severe pain. This condition is caused by damage to the small nerve fibers and its assessment is challenging, due to the lack of simple and objective diagnostic techniques. The present study aimed to develop a contactless photoplethysmography system using simple instrumentation, for objective and non-invasive assessment of small cutaneous sensory nerve fiber function.

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Pseudoxanthoma elasticum (PXE) is a rare multisystemic autosomal recessive connective tissue disease. In most cases, skin manifestations of PXE are the first to develop, followed later by severe ocular and cardiovascular complications. In our present study, in addition to dermoscopy, we introduced novel techniques, autofluorescence (AF) and diffuse reflectance (DR) imaging for the assessment of affected skin sites of five PXE patients.

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Keratins are one of the main fluorophores of the skin. Keratinization disorders can lead to alterations in the optical properties of the skin. We set out to investigate a rare form of keratinopathic ichthyosis caused by mutation with two different optical imaging methods.

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Evaluation of skin erythema severity by dermatoscopy in dogs with atopic dermatitis.

Vet Dermatol

April 2021

Department of Clinical Sciences, College of Veterinary Medicine, NC State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA.

Background: To estimate the extent and severity of atopic dermatitis (AD)-related skin lesions, clinical trials enrolling dogs with AD often use categorical scales such as the Canine Atopic Dermatitis Extent and Severity Index, 4 iteration (CADESI-04) and Canine Atopic Dermatitis Lesion Index (CADLI). Despite recent progress in the standardization of these AD-grading scales, the evaluation of the severity of skin lesions (including erythema) remains subjective.

Objectives: To validate an optical set-up with a smartphone and a dermatoscope for the objective estimation of skin erythema severity in atopic dogs.

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Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors.

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In a present paper, we demonstrate novel approach to form ceramic coatings with incorporated ZnO nanoparticles (NPs) on low modulus TiZrNb alloy with enhanced biocompatibility and antibacterial parameters. Plasma Electrolytic Oxidation (PEO) was used to integrate ZnO nanoparticles (average size 12-27 nm), mixed with Ca(HPO) aqueous solution into low modulus TiZrNb alloy surface. The TiZrNb alloys with integrated ZnO NPs successfully showed higher surface porosity and contact angle.

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Accuracy of an Affordable Smartphone-Based Teledermoscopy System for Color Measurements in Canine Skin.

Sensors (Basel)

October 2020

Vetamplify SIA, Veterinary Services, 57/59-32 Krišjāņa Valdemāra Str., LV-1010 Rīga, Latvia.

Quality smartphone cameras and affordable dermatoscopes have enabled teledermoscopy to become a popular medical and veterinary tool for analyzing skin lesions such as melanoma and erythema. However, smartphones acquire images in an unknown RGB color space, which prevents a standardized colorimetric skin analysis. In this work, we supplemented a typical veterinary teledermoscopy system with a conventional color calibration procedure, and we studied two mid-priced smartphones in evaluating native and erythematous canine skin color.

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In the present work, we report on the modelling of processes at the zinc oxide and polydopamine (ZnO/PDA) interface. The PDA layer was deposited onto ZnO nanorods (NRs) chemical bath deposition. The defect concentrations in ZnO before and after PDA deposition were calculated and analysed.

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Because dogs tolerate conventional rectal temperature measurements poorly, a calibrated infrared thermometer was tested for assessing canine body surface temperature. Body surface temperature of 204 dogs was estimated on various sites (digit, snout, axilla, eye, gum, inguinal region, and anal verge). Having rectal temperature as the gold standard, temperature difference, Spearman's correlation coefficient, hyperthermia and hypothermia detection sensitivity and specificity, and stress response score was calculated for each measurement site.

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The precise detection of cancer cells currently remains a global challenge. One-dimensional (1D) semiconductor nanostructures (e.g.

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Microcirculation and mean arterial pressure: friends or foes?-reply.

Ann Transl Med

June 2020

Laboratory of Biophotonics, Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga, Latvia.

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Kinetics of TiO photochromic response in different hole scavenging solvents.

Photochem Photobiol Sci

August 2020

Research Laboratory of Functional Materials Technologies, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena 3/7, 1048 Riga, Latvia, USA.

There has recently been a renewed interest in the photochromic properties and uses of TiO as a potential candidate for smart windows. However, the surrounding medium of TiO nanoparticles (NPs) is of equal importance, as it facilitates hole scavenging and, in turn, photochromism. Here, we investigated the impact of scavenging power on the photochromic properties of TiO.

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Zinc oxide nanoparticles were prepared from Zn(CO)(OH) precursor, capped with poly(vinylpyrrolidone) (PVP), and annealed at 600 °C. The obtained powders were characterized by a powder X-ray diffraction (PXD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible spectroscopy (UV-vis), Raman spectroscopy, infrared spectroscopy (IR), thermal analysis (TGA/DTA), and third-order nonlinear (NL) optical measurement. Morphological evaluation by TEM and SEM measurements indicated that the precursor micro-particles are ball-shaped structures composed of plates with a thickness of approximately 10 nm.

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Remitted photon path lengths in human skin: measurement data.

Biomed Opt Express

May 2020

Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Raina Blvd 19, Riga, LV-1586, Latvia.

The remitted photon path lengths in human skin can be estimated by modelling; however, there are very few experimental data available to validate the simulations. This study exploited the photon time of flight method where picosecond laser pulses at seven wavelength bands in the spectral range 560-800 nm were launched into forearm skin of 10 volunteers via an optical fiber. The pulses of back-scattered light were detected via another optical fiber placed at variable distance (1, 8, 12, 16 or 20 mm) from the input fiber, with subsequent analysis of their shapes for all 35 spectral-spatial combinations.

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Operating a cesium sputter source in a pulsed mode.

Rev Sci Instrum

February 2020

Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden.

A scheme is presented for pulsing of a cesium sputter negative ion source by periodically switching on and off the high voltage driving the sputtering process. We demonstrate how the pulsed ion beam can be used in combination with a pulsed laser (6 ns pulse length) that has a 10 Hz repetition rate to study the photodetachment process, where a negative ion is neutralized due to the absorption of a photon. In such experiments, where the ion beam is used only for a small fraction of the time, we show that the pulsed mode operation can increase the lifetime of a cathode by two orders of magnitude as compared with DC operation.

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ZnO/polyaniline composite based photoluminescence sensor for the determination of acetic acid vapor.

Talanta

May 2020

University of Latvia, Institute of Atomic Physics and Spectroscopy, 19 Rainis Blvd., Riga, LV, 1586, Latvia; Sumy State University, Center for Collective Use of Research Equipment, 31 Sanatorna Street, 40000, Sumy, Ukraine. Electronic address:

In this study, we report a novel ZnO/polyaniline (PANI) nanocomposite optical gas sensor for the determination of acetic acid at room temperatures. ZnO nanorods, synthesized in powder form were coated by PANI (ZnO/PANI) by chemical polymerization method. The obtained nanocomposites were deposited on glass substrate and dried overnight at room temperature.

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