Akutna toksičnost maneba u punoglavaca smeđe i zelene krastače

Pesticides used in agriculture can have hazardous effects on aquatic organisms, and amphibians are even more threatened than other aquatic vertebrates. Maneb is widely used to control fungal diseases on crops, fruits, and vegetables. The aim of this study was to investigate the acute toxic effects of maneb on the common (Bufo bufo) and green toad (Pseudepidalea viridis) tadpoles. Tadpoles at the development stage 21 were exposed to maneb (0-5 mg L-1) for 120 h. Maneb LC50 values at hour 120 were 1.966 mg L-1 for B. bufo and 0.332 mg L-1 for P. viridis. To the best of our knowledge, these are the first published LC50 findings for the two species. Visceral oedema and tail deformations were observed in both species. We also observed liver necrosis, pronephric tubule deformations, somite deteriorations, and visceral oedema at maneb concentrations ≥0.1 mg L-1 for B. bufo and ≥0.05 mg L-1 for P. viridis. Our results show that B. bufo tadpoles have a much higher resilience to maneb than P. viridis tadpoles. This resilience seems to be related to the larger size of the B. bufo tadpoles and their ability to metamorphose faster in adverse conditions. Future research should look into the mechanisms of toxic action of maneb in anurans.Pesticidi u poljoprivrednoj uporabi mogu biti opasni za vodene organizme, a najugroženiji među vodenim kralježnjacima su vodozemci. Maneb se rabi za suzbijanje gljivičnih bolesti usjeva, voća i povrća. Cilj ovog istraživanja bio je utvrditi akutnu toksičnost maneba u punoglavaca smeđe (Bufo bufo) i zelene krastače (Pseudepidalea viridis). U tu smo svrhu punoglavce u 21. stadiju razvoja izložili manebu (0-5 mg L-1). Po svršetku izloženosti (120 h), LC50 maneba iznosio je 1,966 mg L-1 u B. bufo te 0,332 mg L-1 u P. viridis. Koliko znamo, ove vrijednosti dosada nisu objavljene za ove dvije vrste. Osim letalne koncentracije, pri koncentracijama maneba ≥0.1 mg L-1 za B. bufo odnosno ≥0.05 mg L-1 za P. viridis utvrdili smo i nekrozu jetara, deformacije predbubrežnoga kanalića, propadanje somita te visceralni edem. Naši rezultati pokazuju da su punoglavci smeđe krastače značajno otporniji na maneb od punoglavaca zelene krastače

Akutna toksičnost maneba u punoglavaca smeđe i zelene krastače

Pesticides used in agriculture can have hazardous effects on aquatic organisms, and amphibians are even more threatened than other aquatic vertebrates. Maneb is widely used to control fungal diseases on crops, fruits, and vegetables. The aim of this study was to investigate the acute toxic effects of maneb on the common (Bufo bufo) and green toad (Pseudepidalea viridis) tadpoles. Tadpoles at the development stage 21 were exposed to maneb (0-5 mg L-1) for 120 h. Maneb LC50 values at hour 120 were 1.966 mg L-1 for B. bufo and 0.332 mg L-1 for P. viridis. To the best of our knowledge, these are the first published LC50 findings for the two species. Visceral oedema and tail deformations were observed in both species. We also observed liver necrosis, pronephric tubule deformations, somite deteriorations, and visceral oedema at maneb concentrations ≥0.1 mg L-1 for B. bufo and ≥0.05 mg L-1 for P. viridis. Our results show that B. bufo tadpoles have a much higher resilience to maneb than P. viridis tadpoles. This resilience seems to be related to the larger size of the B. bufo tadpoles and their ability to metamorphose faster in adverse conditions. Future research should look into the mechanisms of toxic action of maneb in anurans.Pesticidi u poljoprivrednoj uporabi mogu biti opasni za vodene organizme, a najugroženiji među vodenim kralježnjacima su vodozemci. Maneb se rabi za suzbijanje gljivičnih bolesti usjeva, voća i povrća. Cilj ovog istraživanja bio je utvrditi akutnu toksičnost maneba u punoglavaca smeđe (Bufo bufo) i zelene krastače (Pseudepidalea viridis). U tu smo svrhu punoglavce u 21. stadiju razvoja izložili manebu (0-5 mg L-1). Po svršetku izloženosti (120 h), LC50 maneba iznosio je 1,966 mg L-1 u B. bufo te 0,332 mg L-1 u P. viridis. Koliko znamo, ove vrijednosti dosada nisu objavljene za ove dvije vrste. Osim letalne koncentracije, pri koncentracijama maneba ≥0.1 mg L-1 za B. bufo odnosno ≥0.05 mg L-1 za P. viridis utvrdili smo i nekrozu jetara, deformacije predbubrežnoga kanalića, propadanje somita te visceralni edem. Naši rezultati pokazuju da su punoglavci smeđe krastače značajno otporniji na maneb od punoglavaca zelene krastače

Managing health and safety risks in restoration/renovation of historic buildings

Restoration and renovation of historic buildings aim to preserve and sustain those buildings with their original state. This fact is important to conserve historical values for a society as well as for sustainable city planning. Restoration projects have their own occupational health and safety risks and differ from ordinary construction projects. Additionally, implementation of safety measures according to the current regulations are very difficult due to geometrical structure, type of material used and preservation consideration for the structural and architectural elements of the historic buildings. Since the risks as well as mitigation and abatement techniques differ from conventional buildings, restoration projects require paying attention to establish safety and health plan and risk management system to implement safety and health measures. In this paper, different health and safety risks of the restoration projects are discussed. Different safety and health practices are dealt with ordinary structures, risk assessment is made according to specific risks, findings are revealed in some certain restoration projects in Turkey and a new approach for health and safety management in restoration projects is introduced.Publisher's Versio

In situ copper (I) formation in atom transfer radical polymerization

Atom Transfer Radikal Polimerizasyon (ATRP) yakın dönemde birçok akademik araştırmaya konu olmuş kontrollü/”yaşayan” radikal polimerizasyon (LRP) yöntemlerindendir. Yüksek maliyetli ve hazırlık esnasında kolaylıkla oksitlenebilen düşük oksidasyon basamağındaki metal tuzları katalizliğinde gerçekleşmesi ATRP’nin en büyük dezavantajlarındandır. Bu çalışmada stiren (St) ve metil metakrilatın (MMA) ATRP’si Cu (II)/ N,N,N’,N”,N”-pentametildietilentriamin (PMDETA)/ p-metoksitiyofenol ya da sodyum tiyofenolat (PhSNa) katalizliğinde belirli miktarda hava varlığında sırasıyla 110 ve 90 oC’de gerçekleştirilmiştir. Normal ATRP’den farklı olan bu yeni yaklaşım, tiyofenol türevi gibi elektron transfer bileşiklerinden Cu (II)’ye (deaktivatör) elektron transferi sonucu Cu(I)’in (aktivatör) in situ oluşumuna dayanmaktadır. In situ Cu(I) oluşumu CuCl2/PMDETA/PhSNa’nın N,N-dimetilformamid içindeki karışımından belirli zaman aralıklarında alınan örneklerin UV-VIS ölçümleriyle izlenmiştir. Bunun yanında p-metoksitiyofenol ve PhSNa’nın elektron transfer bileşiği olarak polimerizasyon kinetiği üzerine etkileri incelenmiştir. Polimerizasyonların monomer konsantrasyonuna göre 1. dereceden kinetik izlediği ve sayıca ortalama molekül ağırlıklarının % dönüşümle orantılı olarak arttığı gözlenmiştir. Ayrıca CuBr2/PMDETA/p-metoksitiyofenol katalizliğinde belirli miktarda hava varlığında gerçekleştirilen ATRP ile sentezlenen polistiren (PS) homopolimeri MMA ile zincir uzatma polimerizasyonunda makrobaşlatıcı olarak kullanılıp PS-PMMA blok kopolimeri sentezlenmiştir. Yapılan zincir uzatma polimerizasyonu ve kinetik çalışmalar ile Cu(II)/PMDETA/p-metoksitiyofenol ya da PhSNa katalizli polimerizasyonların yaşayan karakterde olduğu kanıtlanmıştır. ATRP'de in situ Cu(I) oluşumu metodu normal ATRP’nin bütün avantajlarını taşımasının yanı sıra düşük maliyetli ve hava koşullarında kararlı Cu(II) tuzlarının kullanılmasına ve polimerizasyonun sınırlı miktarda hava varlığında gerçekleştirilmesine olanak tanımaktadır. Böylelikle ATRP’nin uygulanabilirliğini kısıtlayan en önemli dezavantajlardan biri ortadan kaldırılmıştır. Anahtar Kelimeler: Atom Transfer Radikal Polimerizasyon, stiren, metilmetakrilat, tiyofenol.Radical polymerization is industrially the most widespread method to produce polymeric materials. This is due to its tolerance to protic compounds (such as water), a high reaction rate, convenient temperature range and very minimal requirements for purification of monomers, solvents. Furthermore, radical polymerizations can be carried out in bulk, in solution, aqueous suspension, emulsion, and dispersion. The major drawback of conventional radical polymerization is the lack of control over polymer structure. Due to slow initiation fast propagation, and subsequent transfer or termination, polymers with high molecular weight and broad molecular weight distribution are generally produced. These features are reflected in the physical and mechanical properties of the produced polymers. Living polymerization is free from side reactions such as termination and chain transfer and can thus generate polymers of well-defined architectures and molecular weights. However, ionic polymerization is limited to a handful of monomers; it also requires very stringent drying, exclusion of moisture, and also very low temperatures. The recent development of the living (or controlled/"living") radical polymerization (LRP) opened up a new and versatile route to the synthesis of well-defined, polymers with low polydispersities and various possible architectures. Among them atom transfer radical polymerization (ATRP) is the most convenient and useful method to synthesize polymers with well-controlled molecular weight and molecular weight distribution from a wide range of monomers. The advantages of ATRP, in comparison with other LRP processes, include the large range of available monomers and (macro)initiators, the simplicity of reaction setup, and the ability to conduct the process over a large range of temperatures, solvents, and dispersed media. However, major disadvantages of ATRP are high cost and easy oxidation of metal salt in lower oxidation state. These can be overcome by in situ Cu(I) generation via an electron transfer from a reducing agent to a more stable higher oxidation state metal salt. This approach is different than the normal ATRP in two respects: In this system, reactive Cu(I) species are formed in situ via redox process between Cu(II) and reducing agents. Therefore, the small concentration of Cu(I) promotes the low concentration of transient radicals, in addition, the initial presence of Cu(II) (persistent radical) facilitates the deactivation process and thus suppresses undesirable radical-radical coupling reaction. The unavoidable oxidation of catalyst or the oxygen induced polymerization by the diffused oxygen as it was reported in normal ATRP does not play detrimental role in this system. In this study ATRP of styrene (St) and methylmethacrylate (MMA) were conducted in the presence of limited amount of air using Cu(II)/PMDETA as catalyst, sodium thiophenolate (PhSNa) or p-methoxythiophenol as reducing agent. Electron transfer to higher oxidation state metal salts from reducing agents such as PhSNa or p-methoxythiophenol provided the in situ formation of copper (I) species which is activator in copper catalyzed LRP. During the in situ generation of activator, thiophenol derivative is oxidized to yield disulfide. In this respect, UV-VIS measurements were performed to prove the electron transfer reaction between PhSNa and Cu(II)/PMDETA complex. Secondly, polymerization kinetics were followed to compare the efficiency of p-methoxythiophenol and PhSNa as reducing agent. Besides, to investigate chain-end functionality of synthesized polymers, PS macroinitiator prepared by this method was used as macroinitiator for chain extension polymerization with MMA under similar conditions. In summary a new method for conducting ATRP was developed. The procedure used to generate copper (I) species relies on electron transfer from reducing agents to copper (II) species rather than reduction by organic radicals. This novel procedure has all the benefits of a normal ATRP process combined with the additional benefit of adding the catalyst complex to the reaction mixture in its more stable higher oxidation state. It is anticipated that in situ copper (I) formation method will facilitate the commercial application of ATRP. Keywords: Atom Transfer Radical Polymerization (ATRP), styrene, methyl methacrylate, thiophenol. 

Modelling Shared Bicycle Demand Using Artificial Neural Networks

Since bicycles are based entirely on muscle power, they are the transportation vehicles with the lowest negative impact on the environment. In addition, since they are an active mode of transportation, they are also named among the leading modes in terms of sustainability. They are also the leading vehicles types among the micromobility systems, which can be considered as small-sized and individual transportation modes, in terms of their historical background as well as purchasing and operating costs. Today, bicycle ridership rates are increasing thanks to the bike-sharing or rental services provided by both local governments and companies in the private sector. Traveling by bicycle, rather than using a motor vehicle, has a positive effect on the natural environment as it does not cause pollutant gas emissions and effects the traffic jams minimally. It is crucial to investigate the periodic changes in the use of shared bicycle systems, especially in order to define the factors that affect this modal shift and to predict the demand for bicycle use in the future. Within the scope of the developed study, the changes in bicycle use and various factors affecting it were investigated in 4 of the cities in which one of Turkey's leading companies in micromobility provides bicycle sharing services. The values regarding bicycle use were then modelled using artificial neural networks. Thanks to the developed model, it will be possible to predict the number of future trips in the cities where bike sharing service is provided and the periodic changes of these trips, as well as to make estimations about the passenger demand that will arise in a city where the new service will be provided.This study has been prepared with the contribution of Yapidrom Technology JSC and with the support from the European Union's H2020 research and innovation programme under the RECIPROCITY Project (Grant NO 101006576)

Akutni toksični učinci kadmija na ličinke zelene žabe, Pseudepidalea variabilis (Pallas, 1769) (Amphibia: Anura)

The environmental impact of cadmium use and its accumulation in nature have increased to alarming levels. This study aimed to morphologically and histologically investigate the acute toxic effects of cadmium on green toad, Pseudepidalea variabilis (Pallas, 1769) larvae. Embryos were obtained from specimens collected in amplexus from nature and kept under laboratory conditions until stage 26, when they were exposed to cadmium (0, 1, 5, 10, 25, and 50 μg L-1) for 96 h. The LC10, LC50, and LC90 values of cadmium were calculated to be 26.98, 35.35, and 46.31 μg L-1, respectively. Our results showed that cadmium had a negative effect on the body size of P. variabilis larvae (over 1 μg L-1). Histological examination detected a fusion of gill lamellae, liver haemorrhage, oedema in the abdominal cavity, and deformations of pronephric tubules (over 10 μg L-1). Our findings suggest that the green toad was sensitive to the cadmium treatment, with LC50 values lower than those reported by other studies. Thus, this species could be considered a reliable indicator species of environmental stress in aquatic ecosystem.Štetni utjecaji kadmija na okoliš i njegovo nakupljanje u prirodi posljednjih su godina poprimili zabrinjavajuće razmjere. U okviru ove studije istražili smo akutne toksične učinke kadmija na morfologiju i histologiju ličinaka zelene žabe, Pseudepidalea variabilis (Pallas, 1769). Embriji žabe dobiveni su od jedinki koje su u fazi ampleksusa prikupljene u prirodi. U laboratorijskim uvjetima embriji su bili držani do razvojnog stadija 26, kada su izloženi kadmiju u koncentracijama od 0, 1, 5, 10, 25 i 50 μg L-1 tijekom 96 sati. U pokusu smo odredili sljedeće letalne koncentracije kadmija: LC10 26,98 μg L-1, LC50 35,35 μg L-1 i LC90 46,31 μg L-1. Izloženost kadmiju u koncentracijama većim od 1 μg L-1 negativno je utjecala na veličinu tijela ličinaka. Histološke analize upućuju na sljepljivanje škržnih listića, krvarenja u jetrima, pojavu edema u trbušnoj šupljini i deformacije pronefričkih kanalića (pri koncentracijama većim od 10 μg L-1). Dobiveni rezultati pokazali su da je zelena žaba vrlo osjetljiva na kadmij, na što upućuje vrijednost LC50 koja je u našem pokusu bila niža od vrijednosti zabilježenih u drugim istraživanjima. Prema tome, ta se vrsta može smatrati pouzdanim pokazateljem okolišnog stresa u slatkovodnim ekosustavima

Improving the Surface Quality and Mechanical Properties of Selective Laser Sintered PA2200 Components by the Vibratory Surface Finishing Process

This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the asbuilt state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials

Case Report of An Incidental Unicentric Castleman Disease

DergiPark: 889347tmsjAims: To emphasize the hardship of diagnosing Castleman disease and present a potential treatment method. Case Report: A sixty-three-year-old male patient was admitted to the outpatient clinic with an attack of acute cholecystitis. The patient’s abdominal computed tomography revealed an incidentally detected lipid dense solid mass (64x53x37 mm) at the level of right renal hilum with 29x13 mm solid components in the middle. The patient was admitted to the urology department and underwent surgery where the mass was totally excised due to suspicion of a malignancy (liposarcoma). Histopathological examination later on resulted with unicentric Castleman disease, hyaline vascular subtype. Conclusion: Since unicentric Castleman disease has an asymptomatic clinical course and is quite rare, it is necessary to rule out many potential possibilities before reaching a proper diagnosis. However, unicentric Castleman disease usually exhibits a good prognosis after the removal of the affected lymph node. Still, Castleman disease should be a candidate considered in the differential diagnosis of patients with incidentally discovered lymphadenopathy. On the whole, for a better understanding of underlying pathophysiology, there still lies a gap to be filled with knowledge acquired through further studies

The evaluation of vitamin K status in children with febrile seizure

Background: Febrile seizure is the most common neurological disorder in childhood. The exact pathophysiology of febrile seizures is unknown. Recent studies showed the role of vitamin K in nonhematological and inflammatory disorders. This study aimed to investigate the serum vitamin K levels in children with febrile seizures. Aims: To evaluate vitamin K levels in children with febrile seizures. Study Design: Prospective case-control study. Methods: This multicenter study examined representative populations in 8 different cities in Turkey between April 1, 2018 and April 1, 2019. Blood samples were taken from all children at presentation. Vitamin K1, vitamin K2, tumor necrosis factor-alpha, interleukin 1 beta, and interleukin 6 levels were determined by enzyme-linked immunosorbent assay. Results: A total of 155 children were included in the study—84 children with febrile seizures and 71 children in febrile control group. Serum vitamin K1 and vitamin K2 levels were also higher in children with febrile seizures than in the controls. The results of statistical analysis showed that vitamin K1 and vitamin K2 levels were correlated with tumor necrosis factor-alpha, interleukin 1 beta, and interleukin 6 levels. The median vitamin K1 and vitamin K2 levels of children experiencing their first febrile seizure were higher than those in children with recurrent febrile seizures. Type of febrile seizure has no effect on serum vitamin K1 and vitamin K2 levels. Conclusion: In children with febrile seizures, vitamin K levels are higher than those in the control group. These new findings may contribute to elucidating the etiopathogenesis of febrile seizures