2-OXO-1,2,3,4-tetrahydropyrimidine-azo-pyridone dye : a potential application as new green-emitting fluorescent probe

Molecular imaging is a relatively new research field, which has demonstrated great potential, especially in clinical oncology – from drug development to cancer early detection. The key of fluorescence imaging is the construction of fluorescent probe which is composed of two parts, the recognition groups to recognize cancer cells, and fluorophores to signal the recognition events. In this research, the structure of new fluorescent azo dye based on 2-oxo-1,2,3,4-tetrahydropyrimidin and 2-pyridone moieties has been reported. The absorption and emission properties of the investigated azo dye have been studied using UV-Vis and fluorescence spectroscopy. The obtained results suggest that studied dye meets the requirements for new green-emitting fluorescent probe, suitable for further application in biomedical researches

Friction Force Microscopy of Deep Drawing Made Surfaces

Aim of this paper is to contribute to micro-tribology understanding and friction in micro-scale interpretation in case of metal beverage production, particularly the deep drawing process of cans. In order to bridging the gap between engineering and trial-and-error principles, an experimental AFM-based micro-tribological approach is adopted. For that purpose, the can’s surfaces are imaged with atomic force microscopy (AFM) and the frictional force signal is measured with frictional force microscopy (FFM). In both techniques, the sample surface is scanned with a stylus attached to a cantilever. Vertical motion of the cantilever is recorded in AFM and horizontal motion is recorded in FFM. The presented work evaluates friction over a micro-scale on various samples gathered from cylindrical, bottom and round parts of cans, made of same the material but with different deep drawing process parameters. The main idea is to link the experimental observation with the manufacturing process. Results presented here can advance the knowledge in order to comprehend the tribological phenomena at the contact scales, too small for conventional tribology

First Report on Natural Infection of Paeonia tenuifolia by 'Candidatus Phytoplasma solani' in Serbia

Peony (Paeonia tenuifolia L.) is a herbaceous perennial plant known for its beautiful and showy flowers. In Serbia it is native to the Deliblato Sands and is used as an ornamental and medicinal plant in folk medicine. This plant species has become a rarity and for that reason peony was introduced into a botanical collection near Backi Petrovac (northern Serbia), where it has been maintained since 1988. Reddening of lower leaves observed on 10% of plants (5 of 50) in the collection at flowering in May 2012 gradually progressed throughout affected plants by the seed maturation stage. Five leaves from each of three reddened and three symptomless plants were sampled at the end of July 2012. Total nucleic acid was extracted separately from individual leaves (30 samples) using the CTAB (cetyltrimethylammonium bromide) method (2). A nested PCR assay using universal primer pairs P1/P7, followed by R16F2n/R16R2 (4), amplified 16S rDNA fragments of 1.8 and 1.2 kb, respectively. DNA from all three reddened plants (15 samples) yielded 1.2-kb amplicons after nested PCRs. Restriction fragment length polymorphism (RFLP) patterns obtained by digestion of nested products with endonucleases AluI, TruI, HpaII, or HhaI (Thermo Scientific, Lithuania) (4) were identical to those of the STOL reference strain included for comparative purposes, indicating that symptoms were consistently associated with plant infection by ‘Ca. Phytoplasma solani’ (Stolbur) phytoplasma. The 16S rDNA amplicons from two peony plants (1.2 kb from B15 and 1.8 from B18) were sequenced (GenBank Accession No. KC960487 and KF614623, respectively). BLAST analysis revealed a 100% identity between the sequences and GenBank sequences of Stolbur phytoplasma, subgroup 16SrXII-A phytoplasma, previously detected in maize (JQ730750) in Serbia and red clover (EU814644.1) in the Czech Republic. Phytoplasma associated diseases of other species of the genus Paeonia (P. lactiflora Pall. and P. suffruticosa Andrews) have been described elsewhere. Disease symptoms on P. lactiflora from Chile were associated with the phytoplasma that belongs to the ribosomal subgroup 16SrVII-A (‘Ca. Phytoplasma fraxini’) (1). Also, Stolbur phytoplasma from the 16SrXII group was detected on P. suffruticosa plants in China, manifesting yellowing symptoms (3). To our knowledge, this is the first report of naturally occurring Stolbur phytoplasma disease of P. tenuifolia L. in Serbia

Results of IMS participation in international intercomparisons for whole body dosemeters – 10 years of study

The regular participation of an accredited individual monitoring service (IMS) in the international and/or interlaboratory intercomparisons (IC) is required according to ISO/IEC 17025:2017 standard, General requirements for the competence of testing and calibration laboratories. By taking the part in an IC, IMS shows competence, reliability, and has an opportunity to learn further and improve its measurement method. The European Dosimetry Group (EURADOS) Working Group 2 (WG2) has acknowledged the value of the regular IC and also found that data and results from it are fundamental for the harmonization of the measurement process [1]. Thus, EURADOS started a self-sustained program of IC for IMS for external radiation on a biannual basis. The results of an accredited IMS at the Department of Radiation and Environmental Protection, “VINČA” Institute of Nuclear Sciences, Belgrade, Serbia (IMS VINS) in the EURADOS IC for the period 2010-2020 (excluding 2014) are presented. IMS VINS use thermoluminescent whole body dosemeters based on two TLD-100TM (Thermo Scientific™ Harshaw™, USA) detectors. The readouts are done on the Harshaw TLD™ Model 6600 Plus Automated Reader (Thermo Fisher Scientific, USA). The whole glow curve is used for dose estimation (all of 200 channels). The calibration of the dosimetric system is done twice a year in S-Cs (previously in S-Co) field at the secondary standard dosimetry laboratory (SSDL VINS), according to ISO 4037-3:2019. The IC had 40 different reference values of personal dose equivalent, Hp(10) in noted period ranging from 0.431 mSv to 501 mSv. There were 20, 16, 22, 22, 20 dosemeters irradiated in year 2010, 2012, 2016, 2018, 2020, respectively. The radiations were done in 12 different fields: N-60, S-Co, S-Cs, N-40, N-150, S-Cs+Sr90, S-Cs+N-40, W-110, S-Cs+W-250, W-60, S-Cs+W-80, and S-Cs+N-150. The relative response (R) range is from 0.23 to 2.26. Quantile values for R are: 0.23, 0.79, 0.90, 1.1, and 2.26, respectively for (0%, 25 %, 50 %, 75 % and 100 % of points). Mean and standard deviation of R are 0.97 and 0.30, respectively. The performance limits are established according to ISO 14146 trumpet-curve [1]. Due to trumpet-curve there were 6 outliers (2 in 2010, 4 in 2016). All of the outliers were for reference dose around 1 mSv and lower. One outlier from 2010 was irradiated in N-40 field and 30° of incident angle. The other outlier was irradiated in the S-Cs field, without any rotation, and thus should have had a satisfying response. The possible explanation is an insensitive TL detector. The outliers in 2016 were all for N-40 quality and ±60° angle. Thus, considering the low number of outliers (only one true outlier) and expected dosemeters faulty response for given irradiation parameters, we conclude that the IMS VINS dosimetry system had satisfactory behavior during IC from 2010-2020.X JUBILEE International Conference on Radiation in Various Fields of Research : RAD 2022 (Spring Edition) : book of abstracts; June 13-17, 2022; Herceg Novi, Montenegr

First Report of 16SrXII-A Subgroup Phytoplasma (Stolbur) Associated with Reddening of Oenothera biennis in Serbia

Evening primrose (Oenothera biennis L.) is a biennial medicinal, edible, and ornamental plant species. It has attracted great interest for its seed oil that contains gamma linolenic acid, thus distinguishing this plant as a main commercial source of this essential fatty acid (4). This species has been grown as a permanent member of a medicinal plant collection established near Backi Petrovac (northern Serbia) for 22 years. The first disease symptoms were recognized as red spots on leaf rosette in July 2011, spreading gradually during vegetative growth and covering 1/3 to 1/2 of the leaf surface. Symptoms, observed on 16% of the plants (32 of 200) in the second half of May 2012 and on 23% (69 of 300) at the beginning of May 2013, appeared as reddening of lower leaves of flower-bearing stems. Affected plants exhibited stunted growth, while reddening spread over other leaves of flower-bearing stems. In severely affected plants, the flower-bearing stems were poorly developed, frequently forming witches' brooms. For that reason, 30 reddened and 20 symptomless leaves (2 leaves per plant) were sampled in both July 2012 and 2013 and total nucleic acids were extracted. Direct PCR assays were performed using phytoplasma universal primer pair P1/P7 (2) to amplify 1,800-bp fragments (the 16S rRNA gene, the 16S-23S intergenic spacer region, and a part of the 5′ region of the 23S rRNA gene). PCR products were used in nested PCR with primers R16F2n/R2 (2) to amplify 1,200-bp fragments. The identification of phytoplasmas was done using RFLP (restriction fragments length polymorphisms) analyses of R16F2n/R2 amplicons digested with AluI, Kpn I, HpaII, TruI1, or HhaI endonucleases (Thermo Scientific, Lithuania) (2). RFLP patterns were identical to that of STOL reference strain of the 16SrXII-A subgroup, indicating that symptomatic plants were infected with phytoplasma (2). The 16S rDNA nucleotide sequence of representative strain E7 was deposited in GenBank under accession number KF850526. The BLASTn search showed 100% homology to an Iranian strain (KF263684.1) from peach and Serbian strains JQ730742.1 and JQ730750 from valerian and corn, respectively, all belonging to ‘Candidatus Phytoplasma solani’ (Stolbur). Sequencing data confirmed the association of Stolbur phytoplasma with affected O. biennis plants. It has already been reported that phytoplasma infection caused yellows disease of O. biennis (1). Also, the virescence of O. hookeri was associated with phytoplasma strain OAY from aster yellows (AY) group (subgroups 16SrI-B), and selected as the reference strain for the novel taxon ‘Ca. P. asteris’ (3). Here we provide the first report of naturally occurring Stolbur phytoplasma disease of O. biennis in Serbia

2-oxo-1,2,3,4-tetrahydropyrimidine-azo-pyridone Dye: A Potential Application as New Green-Emitting Fluorescent Probe

Molecular imaging is a relatively new research field, which has demonstrated great potential, especially in clinical oncology – from drug development to cancer early detection. The key of fluorescence imaging is the construction of fluorescent probe which is composed of two parts, the recognition groups to recognize cancer cells, and fluorophores to signal the recognition events. In this research, the structure of new fluorescent azo dye based on 2-oxo-1,2,3,4-tetrahydropyrimidin and 2-pyridone moieties has been reported. The absorption and emission properties of the investigated azo dye have been studied using UV-Vis and fluorescence spectroscopy. The obtained results suggest that studied dye meets the requirements for new green-emitting fluorescent probe, suitable for further application in biomedical researches

LiF:Mg,Ti TLD angular dependence evaluation at low energy incident radiation

Accuracy of measurement in individual dosimetry monitoring service is achieved by performing calibration of dosemeters, ensuring that the measured values are traceable to the primary standard for the quantity of interest. Even though a dosemeter can exhibit remarkable performance in the reference calibration radiation field (e.g. 137Cs), its performance can greatly differ under certain conditions. Effects of different influence quantities need to be examined to ensure that the dosemeters are reliable for use in a specific ionizing radiation practice. The most significant radiation characteristic influence quantities are the radiation energy, angle of incidence and dose (rate). International standards issued by IEC and ISO define radiation conditions and procedures for dosemeter type testing under effects of different radiation, environmental and mechanical influence quantities. Dosemeter performance is expressed in terms of relative response and is evaluated by comparing with defined limits of variation, taking into account the measurement uncertainty, according to [IEC 62387:2020, IEC, 2020]. A passive dosimetry system based on LiF:Mg,Ti thermoluminescent dosemeters (TLD) was tested for the effects of photon energy and angle of incidence in two dosemeter orientations, horizontal (up/down) and vertical (left/right), for the measurement of personal dose equivalent (Hp(10) and Hp(0.07)). The dosemeters were read out on the Harshaw TLD™ Model 6600 Plus Automated Reader (Thermo Fisher Scientific, USA), calibrated in 137Cs reference field. Low-energy X-ray reference field N-40, established according to ISO 4037-1:2019 [ISO 4037, ISO, 2019] and ±45°, ±60° angles of incidence were used to examine the passive dosimetry system performance. Limits of variation from -29 % to +67 %, defined in [IEC 62387:2020, IEC, 2020] for energy and angular relative response, were used for performance evaluation. The overresponses for Hp(10) for 45° and 60° were (51 – 62) % and (76 – 88) %, respectively. The results for Hp(0.07) for 45° and 60° were (66 – 69) % and (79 – 95) %, respectively. Thus, for both quantities it was observed that the criteria are met for the angle of ±45°, while for ±60° neither comply with the standard, for both dosemeter orientations, when uncertainties are taken into account. This shows that tested TLD system has high overresponse in low energy photon fields when larger angle of incidence values is encountered. The response could be improved if dosemeters are calibrated using appropriate reference calibration field or if different dosemeter holder is employed.RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts; May 29 - June 2, 2023, Anavyssos, Greec

Isolation, Characterization, Genome Analysis and Host Resistance Development of Two Novel Lastavirus Phages Active against Pandrug-Resistant Klebsiella pneumoniae

Klebsiella pneumoniae is a global health threat and bacteriophages are a potential solution in combating pandrug-resistant K. pneumoniae infections. Two lytic phages, LASTA and SJM3, active against several pandrug-resistant, nosocomial strains of K. pneumoniae were isolated and characterized. Their host range is narrow and latent period is particularly long; however, their lysogenic nature was refuted using both bioinformatic and experimental approaches. Genome sequence analysis clustered them with only two other phages into the new genus Lastavirus. Genomes of LASTA and SJM3 differ in only 13 base pairs, mainly located in tail fiber genes. Individual phages, as well as their cocktail, demonstrated significant bacterial reduction capacity in a time-dependent manner, yielding up to 4 log reduction against planktonic, and up to 2.59 log on biofilm-embedded, cells. Bacteria emerging from the contact with the phages developed resistance and achieved numbers comparable to the growth control after 24 h. The resistance to the phage seems to be of a transient nature and varies significantly between the two phages, as resistance to LASTA remained constant while resensitization to SJM3 was more prominent. Albeit with very few differences, SJM3 performed better than LASTA overall; however, more investigation is needed in order to consider them for therapeutic application

Contact Lenses Characterization by AFM/MFM and Optomagnetic Fingerprint

Polymers conformation states of contact lenses surface are changed during contact lenses production. Since, quality of contact lenses depend of conformation state of surface molecules and its orientation, we investigate contact lenses surface by AFM/MFM and optomagnetic fingerprint techniques. We find out that surface quality and magnetic properties of contact lenses have influence on light transmission. Bearing in mind this result biomedical investigation of surface state and magnetic property of contact lenses on human vision is next step in our research programme