A FIRST RECORD OF THE ALIEN MANTIS SPECIES HIERODULA TENUIDENTATA (MANTODEA: MANTIDAE) IN SERBIA

An alien mantis species, Hierodula tenuidentata, has expanded its areal in Europe in the last few years. It was registered in several European countries, including some on the Balkan Peninsula. Herein are presented for the first time records of H. tenuidentata on the territory of Serbia, several from the capital city of Belgrade, and one from Novi Kneževac, a town in the northern part of country. The species was recognized for the first time in photos posted in a Facebook group of insect lovers and enthusiasts in 2019, but positive identification only took place in 2020 after group members collected specimens. Social networks can be a very important tool for the monitoring of invasive species in general, and invasive mantids in particular, especially due to their size and attractiveness

Lateral-Directional Aerodynamic Optimization of a Tandem Wing UAV Using CFD Analyses

This paper presents the second stage of a tandem fixed-wing unmanned aerial vehicle (UAV) aerodynamic development. In the initial stage, the UAV was optimized by analyzing its characteristics only in symmetrical flight conditions. Posted requirements were that both wings should produce relevant positive lift, the initial stall must occur on the front wing first, the center of pressure should be close to the center of gravity, and longitudinal static stability should be in the optimum range. Computational fluid dynamic (CFD) analyses were performed, where the applied calculation model was derived from the authors’ previous successful projects. The eighth version TW V8 has satisfied all longitudinal requirements. Lateral-directional CFD analyses of V8 showed that the ratio of the lateral and directional stability at the nominal cruising regime was optimal, but both lateral and directional static stabilities were too high. On further development versions, the lower vertical tail was eliminated, a negative dihedral was implemented on the front wing, and four inverted blended winglets were added. Version TW V14 has largely improved lateral and directional stability characteristics, while their optimum ratio at the cruising regime was preserved. Longitudinal characteristics were also well preserved. Maximum lift coefficient and lift-to-drag ratio were increased, compared to the V8

C Tutor usage in relation to student achievement and progress: a study of introductory programming courses in Portugal and Serbia

Previous research studies on introductory programming courses in engineering education in Portugal and Serbia have indicated that although high motivation and high expectations seem to be reported by students, many students may fail the course. This prompted a further inquiry into student attitudes, behavior, and achievement, and it also led to the introduction of C Tutor, a widely known program visualization tool, into courses in both countries. As a result, in the present study, self‐reported student achievement (grades), self‐reported student progress (knowledge improvement and confidence), and self‐reported usage and helpfulness of C Tutor were investigated. Anonymous data about students and their experience in the course, which also included the usage of C Tutor, were collected in a survey in Portugal and Serbia. Quantitative methods, including descriptive statistics, clustering, statistical testing of independence, and partial correlation analysis, were applied in analyses of survey data. The distribution of grades differed between the two countries, but overall attitudes were similar. Various uncovered patterns involving student attitudes and usage of C Tutor may serve as a starting point for new research studies.info:eu-repo/semantics/publishedVersio

Shortened Daily Photoperiod Alleviates Anxiety-like Behaviour by Antioxidant Effect and Changes Serum Fatty Acid Profile in Diabetic Rats

The aim of our study was to investigate the effects of a shortened daily photoperiod on anxiety-like behaviour, brain oxidative stress, lipid status and fatty acid composition of serum lipids in a streptozotocin (STZ)-induced model of diabetes mellitus in rats. Male Wistar rats were divided into the following groups: first group—control group (C12/12); second group—diabetic group (DM12/12; 100 mg/kg STZ); third group—control group exposed to a light/dark cycle 6/18 h (C6/18); fourth group—diabetic group exposed to a light/dark cycle 6/18 h (DM6/18). Anxiety-like behaviour was tested three weeks following STZ injection by elevated plus maze (EPM) and open-field test (OFT). Oxidative stress parameters were measured in the cortex, hippocampus and thalamus, while lipid status and fatty acid methyl esters (FAMEs) were measured in the serum. Both EPM and OFT showed a lower degree of anxiety-like behaviour in the DM6/18 vs. DM12/12 group. Lipid peroxidation in the cortex, hippocampus and thalamus was significantly lower in the DM6/18 vs. DM12/12 group (p < 0.05), associated with an increased level of antioxidant enzymes and protein thiols in the cortex and thalamus. In the DM6/18 group, oleic, vaccenic, dihomo-γ-linolenic and docosahexaenoic acid concentrations were significantly higher in comparison to the DM12/12 group. A shortened daily photoperiod alleviates anxiety-like behaviour in diabetic rats by reduced lipid peroxidation and changes in the serum fatty acids profile

The effect of light/dark cycle changes on vascular permeability, inflammation and visual cycle in streptoyotocin-induced diabezic retinophaty in rats

Introduction: Diabetic retinopathy (DR) is not cured efficiently and changes of lifestyle measures may alleviate its course. The aim of our study was to investigate the effects of shortened daily photoperiod on inflammation and visual cycle in rat retina and retinal pigment epithelium (RPE) in DR. Methodology: Male Wistar rats were divided into the following groups: 1. control; 2. diabetic group (DM) treated with a single intraperitoneal injection of streptozotocin (100 mg/kg); 3. group exposed to light/dark cycle 6/18h for 3 months (6/18); 4. diabetic group exposed to light/dark cycle 6/18h (DM+6/18). Retinal blood vessel permeability was estimated immunohistochemically based on lectin staining, while the expression of genes involved in the visual cycle (SOX9, LRAT, RPE65, OTX2), and inflammation (IL-1, TNF-α) was determined by qRT-PCR in the retina and RPE. Results: Shortened photoperiod reduced neovascularisation and the expression of IL-1 and TNF-α in both retina and RPE. The expression of IL-1 and TNF-α genes in the retina was significantly higher in DM vs. control group (P=0.001). In contrast, retinal IL-1 and TNF-α expressions were significantly lower in DM+6/18 vs. DM group (P=0.001). The expression of IL-1 and TNF-α in RPE was significantly higher in DM vs. control group, however the expression of these genes was significantly lower in DM+6/18 vs. DM group (PIL-1=0.008 and PTNF-α=0.002). The expression of visual cycle genes was significantly up-regulated in RPE in DM+6/18 vs. DM group (P=0.001). Conclusion: Shortened daily photoperiod reduces blood vessel permeability in DR via its anti-inflammatory effect associated with accelerated visual cycle in the retina.Poster Session: Neuroimmunoendocrine Interaction

Direct Separation of Clopidogrel Enantiomers by Reverse-Phase Planar Chromatography Method Using beta-Cyclodextrin as a Chiral Mobile Phase Additive

A simple and rapid TLC method using beta-cyclodextrin as a chiral mobile phase additive (CMPA) was developed for direct separation of S-clopidogrel and its impurity R-clopidogrel. The influence of different factors (stationary phases, organic modifiers, chiral selectors and their concentrations in the mobile phase, and optimal saturation time of the chamber) on enantioseparation was studied. The best resolution of clopidogrel enantiomers was achieved on Polygram (R) cel 300 Ac-10% plates using isopropanol-0.5 mM beta-cyclodextrin (6: 4, v/v) as mobile phase in TLC chamber previously equilibrated with the mobile phase for 20 min. The spots were detected under UV light and using iodine vapours. The method enables rapid separation of clopidogrel enantiomers and can be successfully used in control of stereoselective synthesis of clopidogrel and in control of its purity. Finally, the molecular modelling of the inclusion complexes between the analytes and alpha-, beta-, and gamma-cyclodextrin was performed to investigate the mechanism of the enantiorecognition

Antimicrobial activity of novel chalcones and modulation of virulence factors in hospital strains of Acinetobacter baumannii and Pseudomonas aeruginosa

Acinetobacter baumannii and Pseudomonas aeruginosa are frequent multiresistant nosocomial pathogens that cause wound and pulmonary infections in hospitalized patients. As being increasingly resistant to most clinically available antibiotics, there is a constant need for exploration of new substances that could kill them or inhibit their growth, or alternatively inhibit some of their essential virulence factors. Chalcones are chemical compounds with well-documented antimicrobial potential. The aim of this study was to examine effectiveness of four newly-synthesized chalcones against the multiresistant clinical strains of A. baumannii and P. aeruginosa. Antibacterial activity of chalcones was investigated with broth-microdilution test and time-dependent killing assay. Synergistic effects of tested compounds with antibiotics (meropenem, amikacin and ciprofloxacin) were determined by checkerboard assay. The effects of chalcones on expression of virulence factors in P. aeruginosa (pyocyanin production, swimming and swarming motility) and A. baumannii (twitching and surface-associated motility), along with their biofilm production, were also examined. The obtained results indicate substantial antimicrobial activity of the tested chalcones (MICs = 100-175 mu g/mL) and several synergistic interactions with antibiotics, as well as notable reduction in expression of all investigated virulence factors. These promising results may constitute a good basis for further research

Diet Selection in Finishing Lambs

In a total mixed ration (TMR) feeding system, lambs, as well as other animals, tend to exhibit dietary preferences. The purpose of this paper is to examine differences in the feed selection behavior between lambs previously accustomed to TMR feeding and lambs newly introduced to TMR diets

Antimicrobial activity of novel chalcones and modulation of virulence factors in hospital strains of Acinetobacter baumannii and Pseudomonas aeruginosa

Acinetobacter baumannii and Pseudomonas aeruginosa are frequent multiresistant nosocomial pathogens that cause wound and pulmonary infections in hospitalized patients. As being increasingly resistant to most clinically available antibiotics, there is a constant need for exploration of new substances that could kill them or inhibit their growth, or alternatively inhibit some of their essential virulence factors. Chalcones are chemical compounds with well-documented antimicrobial potential. The aim of this study was to examine effectiveness of four newly-synthesized chalcones against the multiresistant clinical strains of A. baumannii and P. aeruginosa. Antibacterial activity of chalcones was investigated with broth-microdilution test and time-dependent killing assay. Synergistic effects of tested compounds with antibiotics (meropenem, amikacin and ciprofloxacin) were determined by checkerboard assay. The effects of chalcones on expression of virulence factors in P. aeruginosa (pyocyanin production, swimming and swarming motility) and A. baumannii (twitching and surface-associated motility), along with their biofilm production, were also examined. The obtained results indicate substantial antimicrobial activity of the tested chalcones (MICs = 100–175 μg/mL) and several synergistic interactions with antibiotics, as well as notable reduction in expression of all investigated virulence factors. These promising results may constitute a good basis for further research

Targeting outer membrane protein A (OmpA) – inhibitory effect of 2′-hydroxychalcone derivatives on Acinetobacter baumannii and Candida albicans dual-species biofilm formation

Biofilm production facilitates microbial colonization of wounds and catheters. Acinetobacter baumannii produces high levels of biofilm and causes difficult-to-treat nosocomial infections. Candida albicans is another strong biofilm producer which may facilitate A. baumannii adhesion by providing hyphae-mediated OmpA-binding sites. Here we tested the potential of 2′-hydroxychalcones to inhibit dual-species biofilm production of A. baumannii and Candida spp., and further predicted the mechanism of structure-related difference in activity. The results suggest that 2′-hydroxychalcones exhibit potent activity against Candida spp./A. baumannii dual-species biofilm production. Particularly active was trifluoromethyl-substituted derivative (p-CF3), which decreased C. albicans/A. baumannii biomass produced on vein-indwelling parts of the central venous catheterization set by up to 99%. Further, higher OmpA-binding affinity was also calculated for p-CF3, which together with demonstrated significant ompA-downregulating activity, suggests that superior antibiofilm activity of this chalcone against the tested dual-species community of A. baumannii is mediated through the OmpA