EC-SERS detection of thiabendazole in apple juice using activated screen-printed electrodes

Thiabendazole (TBZ), a benzimidazole fungicide used for post-harvest treatment, may be a trace contaminant of food matrices. In this work, we report the first EC-SERS (electrochemical-surface enhanced Raman spectroscopy) detection of TBZ in spiked apple juice using electrochemically (EC) roughened, gold-based screen-printed electrodes (AuSPEs) and portable instrumentation. Polarizing the substrate (−0.8 V vs Ag/AgCl) improves the recorded SERS signal of TBZ, allowing to reach a limit of detection (LOD) in juice of 0.061 ppm with a relatively wide linear range (0.5–10 μM) and good intermediate precision (%RSD < 10). The recovery of TBZ from unprocessed juice was found to be more than 82 %. Furthermore, a proof-of-concept integration of AuSPEs with a miniaturized flow cell for the preconcentration of TBZ and the controlled delivery of sample and reagents has been demonstrated. This approach paves the way for integrated, portable analytical systems applicable for on-site sample collection, processing, and analysis.publishedVersio

Inclusion of preschool children into organized activity in leisure time

All physical activity of preschool children during the day occurs while they are in kindergarten or during their leisure time. The aim of the study was to present the results related to the participation of children in organized activities during leisure time and what is the perception of parents about the scope of their children’s physical activity and the time spent on watching TV, using computers and playing video games (as a part of wider study). The research was conducted in 2017 in the Preschool institution “Naša Radost” in Subotica. The survey questionnaire was filled in by 135 parents for children of the average age of 5.14 years (+0.91). The survey questionnaire contained questions about children’s nutrition (NutriStep survey) and their involvement in organized activities with educational and sports-recreational content during leisure time, as well as parent’s opinion on quantity in child’s sedentary activities. 65.9% of children aged 5 to 7 was found to attend some kind of organized activity, most often within programs of foreign language schools, sports schools and programs with aesthetic presentation of skills is important (ballet, dance and folklore). The largest number of parents reported that their child spent one hour watching TV, using a computer or playing games. About 71% of parents reported that their child was physically active enough. In both cases, a statistically significant difference was found between boys and girls. Within the family circle and within the educational institution, where children spend most of the time, it is necessary to provide conditions for undisturbed growth and development. One of the best ways is through exercising physical activity

Multiple Light Coupling and Routing via a Microspherical Resonator Integrated in a T-Shaped Optical Fiber Configuration System

We demonstrate a three-port, light guiding and routing T-shaped configuration based on the combination of whispering gallery modes (WGMs) and micro-structured optical fibers (MOFs). This system includes a single mode optical fiber taper (SOFT), a slightly tapered MOF and a BaTiO3 microsphere for efficient light coupling and routing between these two optical fibers. The BaTiO3 glass microsphere is semi-immersed into one of the hollow capillaries of the MOF taper, while the single mode optical fiber taper is placed perpendicularly to the latter and in contact with the equatorial region of the microsphere. Experimental results are presented for different excitation and reading conditions through the WGM microspherical resonator, namely, through single mode optical fiber taper or the MOF. The experimental results indicate that light coupling between the MOF and the single mode optical fiber taper is facilitated at specific wavelengths, supported by the light localization characteristics of the BaTiO3 glass microsphere, with spectral Q-factors varying between 4.5 &times; 103 and 6.1 &times; 103, depending on the port and parity excitation

Multiple light coupling and routing via a microspherical resonator integrated in a T-shaped optical fiber configuration system

We demonstrate a three-port, light guiding and routing T-shaped configuration based on the combination of whispering gallery modes (WGMs) and micro-structured optical fibers (MOFs). This system includes a single mode optical fiber taper (SOFT), a slightly tapered MOF and a BaTiO3 microsphere for efficient light coupling and routing between these two optical fibers. The BaTiO3 glass microsphere is semi-immersed into one of the hollow capillaries of the MOF taper, while the single mode optical fiber taper is placed perpendicularly to the latter and in contact with the equatorial region of the microsphere. Experimental results are presented for different excitation and reading conditions through the WGM microspherical resonator, namely, through single mode optical fiber taper or the MOF. The experimental results indicate that light coupling between the MOF and the single mode optical fiber taper is facilitated at specific wavelengths, supported by the light localization characteristics of the BaTiO3 glass microsphere, with spectral Q-factors varying between 4.5 × 103 and 6.1 × 103, depending on the port and parity excitation

TELESNA KOMPOZICIJA, STRUKTURIRANA FIZIČKA AKTIVNOST I KVALITET ISHRANE U ODNOSU NA TEŽINSKI STATUS PREDŠKOLSKE DECE

The aim of this study was to investigate the differences in body composition, involvement in structured PA and nutritional quality habits of normal weight and overweight preschool children from Serbia. Overall, 207 children (5 ± 0.87 year) participated in the study, of which 16 were excluded from the study because of incomplete data. Based on the BMI calculation, the children were divided into two groups: N1=168 normal weight (5.19 ± 0.87 year) and N2=23 overweight children (4.93 ± 0.86 year). There was no statistically significant difference between the observed groups regarding structured PA. Furthermore, no differences in nutritional status were found, underlying the importance of parents promoting good nutritional habits to their children. The preschool age provides a good opportunity for children to develop healthy eating habits in order to maintain healthy growth and development. Nutritional status monitoring in children, along with adequate physical activity, represent  good preventive measures against obesity in a population. Developing and maintaining good overall lifestyle habits at this age could prevent development of some modern diseases at later stages in life.Cilj ovog istraživanja bio je da se ispitaju razlike u telesnoj kompoziciji, uključenosti dece u strukturiranu fizičku aktivnost (FA), kao i kvalitet ishrane dece predškolskog uzrasta sa normalnom i prekomernom telesnom težinom sa područja Srbije. U istraživanju je učestvovalo ukupno 207 dece (5 ± 0,87 godina), od kojih je 16 isključeno iz studije zbog nepotpunih podataka. Na osnovu izračunatog ITM (indeksa telesne mase), deca su podeljena u dve grupe: N1=168 normalne težine (5,19 ± 0,87 godina) i N2=23 dece sa prekomernom telesnom težinom (4,93 ± 0,86 godina). Nisu pronađene statistički značajne razlike između posmatranih grupa u pogledu strukturirane FA, ni razlike u statusu uhranjenosti posmatrane dece, što ukazuje na važnost roditelja i promocije dobrih prehrambenih navika svojoj deci. Predškolski uzrast pruža dobru priliku deci da steknu zdrave navike u ishrani kako bi održali zdrav rast i razvoj. Praćenje nutritivnog statusa kod dece, uz adekvatnu fizičku aktivnost, predstavljaju dobre preventivne mere protiv gojaznosti u populaciji. Razvijanje i održavanje dobrih opštih životnih navika u ovom uzrastu može sprečiti razvoj nekih savremenih bolesti u kasnijim fazama života

Dataset for "Micro-lensed negative-curvature fibre probe for Raman spectroscopy"

This dataset contains data supporting the results presented in the paper "Micro-lensed negative-curvature fibre probe for Raman spectroscopy". It includes the data used to plot each figure (in .txt format). We have developed a novel miniature micro-lensed fibre probe for Raman spectroscopy. The fibre probe consists of a single negative-curvature fibre (NCF) and a spliced, cleaved, micro-lensed fibre cap. Using a single NCF, we have minimized the generated Raman background from the silica and maintained the diameter of the probe to be less than 0.5 mm. In addition, the cap provided fibre closure by blocking the sample from entering the hollow parts of the fibre, enabling the use of the probe in in-vivo applications. Moreover, the micro-lensed cap poses an improved collection efficiency (1.5 times increase) compared to a cleaved end cap. The sensing capabilities of the micro-lensed probe are demonstrated by measuring different concentrations of glucose in aqueous solutions.The different data collection methods used for the collection of the data are described in the paper "Micro-lensed negative-curvature fibre probe for Raman spectroscopy"

Surface-Enhanced Absorption Spectroscopy for Optical Fiber Sensing

Visible and near-infrared spectroscopy are widely used for sensing applications but suffer from poor signal-to-noise ratios for the detection of compounds with low concentrations. Enhancement by surface plasmon resonance is a popular technique that can be utilized to increase the signal of absorption spectroscopy due to the increased near-field created close to the plasmons. Despite interest in surface-enhanced infrared absorption spectroscopy (SEIRAS), the method is usually applied in lab setups rather than real-life sensing situations. This study aimed to achieve enhanced absorption from plasmons on a fiber-optic probe and thus move closer to applications of SEIRAS. A tapered coreless fiber coated with a 100 nm Au film supported signal enhancement at visible wavelengths. An increase in absorption was shown for two dyes spanning concentrations from 5 × 10−8 mol/L to 8 × 10−4 mol/L: Rhodamine 6G and Crystal Violet. In the presence of the Au film, the absorbance signal was 2–3 times higher than from an identically tapered uncoated fiber. The results confirm that the concept of SEIRAS can be implemented on an optical fiber probe, enabling enhanced signal detection in remote sensing applications

Temperature-sensitive photonic liquid crystal fiber modal interferometer

In this paper, we present an experimental investigation of the photonic crystal fiber (PCF) and photonic liquid crystal fiber (PLCF) modal interferometers. The PLCF interferometer is fabricated by infiltrating a liquid crystal (LC) into the PCF and then splicing the effective PLCF between two single-mode fibers (SMF). By heating the PLCF interferometer, we present a possibility to tune optical properties of the propagating light. We also compare PCF- and PLCF-interferometer responses in the presence of changing external temperature conditions

Micro-lensed negative-curvature fibre probe for raman spectroscopy

We developed a novel miniature micro-lensed fibre probe for Raman spectroscopy. The fibre probe consists of a single negative-curvature fibre (NCF) and a spliced, cleaved, micro-lensed fibre cap. Using a single NCF, we minimized the Raman background generated from the silica and maintained the diameter of the probe at less than 0.5 mm. In addition, the cap provided fibre closure by blocking the sample from entering the hollow parts of the fibre, enabling the use of the probe in in vivo applications. Moreover, the micro-lensed cap offered an improved collection efficiency (1.5-times increase) compared to a cleaved end-cap. The sensing capabilities of the micro-lensed probe were demonstrated by measuring different concentrations of glucose in aqueous solutions