Environmentally friendly method for S, N functionalization of graphene quantum dots

Graphene quantum dots (GQDs) show exceptional optical and physical properties. To enable their wider application and improve their optical properties, it is usually necessary to modify them with different functional groups and heteroatoms. Toxic reagents that are potentially harmful to human health and the environment are often used for these procedures. One of the methods that have been successfully used is gamma radiation. In this study, gamma irradiation was employed to achieve structural modification of GQDs without the usage of reactive, toxic chemicals. In this way, an eco-friendly and simple procedure for the incorporation of S and N atoms into the GQDs structure is developed

Association of Leptin and Adiponectin Levels with Somatic and Metabolic Parameters in Discordant Twins

Intrauterusni zastoj rasta (IUZR) je jedan od vodećih uzroka perinatalnog morbiditeta i mortaliteta. Hipertenzija, insulinska rezistencija (IR), dijabetes mellitus tip 2 (T2DM), metabolički sindrom (MS), nizak rast i osteoporoza se dovode u vezu sa IUZR. Skorašnje kliničke i eksperimentalne studije su rasvetlile ulogu koju masno tkivo igra u razvoju insulinske rezistencije i MS kao posledica fetalnog programiranja in utero Cilj ove studije je bio da ispita da li je koncentracija adipokina u krvi pupčanika (P) i u trećem danu (d3) povezana sa usporenim fetalnim rastom i nivoom lipida kod blizanaca sa IUZR. Testirana je povezanost nivoa leptina i adiponektina sa somatskim parametrima i IR na roĎenju i u d3 kod diskordantnih i konkordantnih blizanaca. U studiju je uključeno 36 diskordantnuh (razlika u poroĎajnoj telesnoj masi-TM≥20% računato u odnosu na većeg blizanca) i 42 konkordantna para blizanaca (razlika u TM≤10%), roĎenih≥32 gestacionih nedelja (GN). TM manjeg blizanca je bila ispod 10. percentila (IUZR blizanac) udruženo sa abnormalnim protocima u umbilikalnoj arteriji. Iz venske krvi iz pupčanika kao i iz venske krvi uzete u trećem danu pre jela (d3) su odreĎivani nivoi hormona (leptin, adiponektin, insulin) i bihemijski parametri (glukoza, ukupni holesterol-TC, high density lipoprotein holesterol –HDL C, low density lipoprotein holesterol-LDL C i trigliceridi-TG). Indeksi body mass index-BMI, ponderalni indeks-PI, homeostasis model assesment insulin resistance index-HOMA IR, TG/HDL C i glukoza/insulin (G/I) su izračunati a poslednja tri predstavljaju markere insulinske rezistencije/senzitivnosti. Rezultati: U diskordantnoj grupi nivoi leptina i leptina/TM u krvi iz pupčanika i d3 bili su uporedivi izmeĎu IUZR i blizanaca sa odgovarajućim rastom (appropriate for gestational age-AGA). Kada smo poredili blizance roĎene posle 35 GN koncentracije leptina su bile značajno niže kod IUZR blizanaca u d3 (p=0,011). Nivoi leptina i L/TM u d3 su bili značajno viši kod diskordantnih u odnosu na konkordantne blizance (razlike izmeĎu grupa) (AGA vs. veći, p=0,001 i IUGR vs. manji p=0,004; p=0,001 i p=0,001 respektivno). Koncentracije adiponektina i insulina izmerene na roĎenju i u d3 kao i u podgrupi≥35 GN nisu se statistički značajno razlikovale izmeĎu IUZR i AGA blizanaca. MeĎutim adiponektin/TM je bio viši kod IUZR blizanaca kako u odnosu na AGA blizance tako i u odnosu na manje konkordantne blizance u oba merenja (p=0,002 i p=0,035 respektivno unutar parova i p=0.022 i p=0.002 izmeĎu parova)...Intrauterine growth restriction (IUGR) is one of the leading causes of perinatal morbidity and mortality. Hypertension, insulin resistance (IR), type 2 diabetes mellitus (T2DM), metabolic syndrome (MS), short stature and osteoporosis were found to be associated with IUGR. The recent clinical and experimental studies have highlighted the role of adipose tissue (AT) in the development of insulin resistance and MS as consequences of fetal programming in utero. The aim of this study was to explore whether adipokines concentrations in cord blood (CB) and on day3 (d3) were related to impaired fetal growth and lipids in IUGR twins. The relationship between leptin and adiponectin levels with somatic parameters and IR at birth and on d3 in discordant and concordant twins were tested. Patients and methods: 36 discordant (birth weight BW discordance ≥20% calculated in relation to the heavier cotwins) and 42 concordant (birth weight discordance ≤10%) twin pairs≥32 gestational weeks (GW) were included. BW of the smaller twins was less than 10th percentile (IUGR twins) with abnormal umbilical artery Doppler velocimetry. Umbilical venous CB and venous blood samples on d3 were obtained from each pair of twins in the fasting state both for hormone determination (leptin, adiponectin and insulin) and biochemical analysis (glucose, total cholesterol-TC, high density lipoprotein cholesterol –HDL C, low density lipoprotein cholesterol-LDL C and triglyceride-TG). Indices body mass index-BMI and ponderal index- PI,. homeostasis model assessment insulin resistance index HOMA IR, TG/HDL C and glucose/insulin (G/I) ratio were calculated as a markers of insulin resistance/sensitivity. Results: Within the discordant group leptin and leptin/PTM levels in cord blood and on d3 were comparable between AGA (appropriate for gestational age) twins and IUGR twins. When we compared late preterm and term twins (≥35 GW) on d3 leptin concentration was significantly lower in IUGR twins (p=0,011). Leptin levels and L/BW were higher in discordant as compared to concordant twins (interpair difference) on day 3 (AGA vs. larger, p=0.001 and IUGR vs. smaller, p=0.004; p=0,001 and p=0,001 respectively). Adiponectin and insulin concentration measured in AGA and IUGR twins as well as in≥35 GW discordant twins at birth and on d3 showed no statistically significant differences. However, adiponectin/BW was higher in IUGR twins as compared to AGA cotwins and to smaller concordant twins in CB and on d3 (p=0,002 and p=0,035 respectively for intrapair and p=0.022 and p=0.002 for interpair difference)..

Innovative modifications of graphene quantum dots for improved photodynamic therapy in antibacterial treatment

Considering the rising concern of antibiotic resistance, developing advanced antibacterial solutions is highly needed. The ability of graphene quantum dots (GQDs) to generate reactive oxygen species (ROS) upon light exposure made them promising candidates as agents in photodynamic therapy for combatting infections, including antibiotic-resistant strains. GQDs show versatile chemical, physical, and biological properties such as high fluorescent activity, resistance to photo-bleaching, low toxicity, excellent solubility, and biocompatibility. This research focused on exploring the ability of GQDs to produce singlet oxygen under blue light exposure. We used two singlet oxygen probes, 9,10-anthracenediylbis(methylene) dimalonic acid and 1,3-diphenylisobenzofuran to study photoinduced production radicals from several GQDs. To tune the ability of GQDs to generate ROS, we used gamma irradiation in two different media, the presence of L-cysteine and cyclopentanone. The results showed improvements in singlet oxygen production in both cases. However, the modification conducted with cyclopentanol showed notably higher efficacy in promoting singlet oxygen production. This research demonstrates the increasing significance of GQDs in discovering new methods to combat bacteria. The modification of GQDs with gamma irradiation leads to increased production of singlet oxygen enhancing the effectiveness of photodynamic therapy for treating infections.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Analysis of consumers' willingness to pay for organic and local honey in Serbia

In times of increased concern for human health and care for the environment, it is important to investigate the consumer behavior models in order to better manage the product supply. From the perspective of our research, it is important to learn about consumer attitudes, of a specific product, such as honey, so as to potentially strengthen the economic position of honey producers. The purpose of this article was to explore the consumers' perceptions of organic and local honey in the Republic of Serbia and identify factors that contribute to predicting consumers' willingness to pay (WTP) for organic and local honey. The ordinal regression was used to determine which factors influence the WTP for organic and local honey, and the findings show that the consumers were WTP more for organic honey than for local honey. Socio-economic characteristics of respondents and honey attributes affect consumers' WTP. The higher monthly household income positively influences the WTP for organic honey, while on the other hand, the higher level of education has a positive influence on the WTP for local honey. The WTP for organic honey positively affected by the perceived importance of honey attributes, such as food safety and support for the local community. The frequency of the purchase of the local honey, the recommendations for the local honey purchase and the perceived importance of attributes, such as the care for the environment and nutritional properties, have a positive influence on the consumers' WTP for local honey. From this, we can conclude that our understanding of all the factors that influence a consumer's decision to allocate budget expenses for honey can help all stakeholders in creating an adequate pricing and promotional strategy for honey products

Environmentally Friendly Method for S, N Functionalization of Graphene Quantum Dots

Graphene quantum dots (GQDs) show exceptional optical and physical properties. To enable their wider application and improve their optical properties, it is usually necessary to modify them with different functional groups and heteroatoms. Toxic reagents that are potentially harmful to human health and the environment are often used for these procedures. One of the methods that have been successfully used is gamma radiation. In this study, gamma irradiation was employed to achieve structural modification of GQDs without the usage of reactive, toxic chemicals. In this way, an eco-friendly and simple procedure for the incorporation of S and N atoms into the GQDs structure is developed

MOLECULAR DOCKING ANALYSES OF SOME CYCLOHEXADIENE DERIVATIVES

The molecular docking study was performed with aim to examine the inhibitory potency of two selected cyclohexadiene derivatives (cis-(1S)-3-Fluoro-3,5-cyclohexadiene-1,2-diol (1), and 1,1'-(3,5-Cyclohexadiene-1,3-diyl)dibenzene (2)). The inhibitory potency of compounds 1 and 2 was investigated toward Urokinase Type Plasminogen Activator (uPa). For this purpose AutoDock 4.0 software was used. The thermodynamic parameters achieved from molecular docking simulations, free energy of binding (ΔGbind) and inhibition constant (Ki), are analyzed and discussed. The compound 2 shows better inhibitory potency through uPa, than compound 1.Publishe

Graphene oxide-silver nanowires composites for protection against modern pollution - electromagnetic waves

With the development of the electronic industry, telecommunication, transportation, energy storage devices, and wireless technologies, the need for materials that are able to block electromagnetic waves (EMWs) in low-frequency regions of the spectrum is increasing. A new type of pollution named pollution by EMWs is an inevitable component of modern life. Although materials efficient in blocking the propagation of EMWs are developed, these materials show drawbacks regarding durability and mechanical properties, as well as a high production price and processability. Thus, new eco-friendly and durable materials are needed. Herein, we produced composites based on graphene oxide and silver nanowires to create an efficient shielding barrier for low frequencies (0-15 GHz) EMWs

Supplementary data for article: Romanović, M. Č.; Čobeljić, B.; Pevec, A.; Turel, I.; Anđelković, K.; Milenković, M.; Radanović, D.; Belošević, S.; Milenković, M. R. Synthesis, Crystal Structures and Antimicrobial Activity of Azido and Isocyanato Zn(II) Complexes with the Condensation Product of 2-Quinolinecarboxaldehyde and Girard’s T Reagent. Journal of Coordination Chemistry 2017, 70 (14), 2425–2435. https://doi.org/10.1080/00958972.2017.1343945

Supplementary material for: [https://doi.org/10.1080/00958972.2017.1343945]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/2493

Middle ear tuberculosis: Diagnostic criteria

Introduction. Tuberculous otitis is a diagnostic problem due to the difficulty to obtain microbiological, histomorphological and cytological confirmation of the disease. Objective. Our objective was to compare clinical and radiological characteristic and development of otogenic complications in patients with tuberculous otitis and otitis with cholesteatoma as the most destructive form of chronic nonspecific otitis in the purpose of establishing the diagnostic criteria for tuberculous otitis. Methods. Medical records of 12 patients with tuberculous otitis and 163 patients with cholesteatoma treated at the Institute of Otorhinolaryngology and Maxillofacial Surgery in Belgrade during the eight-year period were analyzed. All of the patients underwent otomicroscopic, audiological and radiological examination of the thorax and temporal bone, microbiological examination of the secretion and histomorphological examination of the tissue taken during middle ear surgery. Statistical analysis was done using χ2 test with Yates correction. Results. Otogenic complication as facial palsy and sensorineural hearing loss were more frequent in tuberculous otitis patients, than in cholesteatoma. Also, fistulas of the labyrinth and facial canal bone destruction were also more frequent in tuberculous otitis than in cholesteatoma. A larger extent of temporal bone destruction was noticed on CT scans of the temporal bone in half of the patents with tuberculous otitis. Coexistence with miliary pulmonary tuberculosis was detected in one third of the patients. There were no microbiological or histomorphological confirmations of the disease, except in one case with positive Ziehl-Neelsen staining. Conclusion. Tuberculous otitis media should be considered in patients with serious otogenic complications and with shorter duration of ear discharge, and in association with diagnosed miliary pulmonary tuberculosis and extensive temporal bone destruction. Polymerase chain reaction still is not reliable for diagnosis