Biofuels - Top Subject

Velik broj predavanja u sekciji B Primjena goriva i zahtjevi kvalitete i zaštite okoliša na prošlogodišnjem 39. stručno-znanstvenom simpoziju GORIVA 2006 obrađivao je teme o biogorivima. Autori su se u radovima bavili aktualnom temom uvođenja biogoriva kao zamjene ili komponente u mineralnim gorivima u uporabi u prometu. O biogorivima su govorili i proizvođači goriva i proizvođači aditiva i kolege s fakulteta baveći se tim gorivima sa strane primjene u vozilima. Tema je aktualna u svijetu, Europi, a postaje i kod nas u Hrvatskoj. Europska komisija je 2003. godine donijela uredbu 2003/30/EC o promociji uporabe biogoriva u prijevozu. Rastom životnog standarda upravo sektor prometa bilježi neprestani porast motornih vozila i potrošnje motornih goriva. Ključni pokretači europskih političara kod donošenja ove uredbe su bili: 1. traženje veće sigurnosti opskrbe energijom u Europi - oslobađanje od dijela uvoza energije iz naftom bogatih zemalja zahvaćenih stalnim ratnim prijetnjama, 2. briga za razvoj poljoprivrede i zbrinjavanje viškova poljoprivrednih proizvoda, kako bi se sačuvala radna mjesta u poljoprivrednom sektoru, te 3. nadasve briga za smanjenje emisije stakleničkih plinova, kako bi se ublažio intenzitet klimatskih promjena.A number of lectures in section B Fuel application, quality and environmental protection requirements on last year’s 39th scientific symposium FUELS 2006 has treated the subject of biofuels. The authors have in their papers treated the topical subject of introducing biofuels as replacement or component in mineral fuels used in traffic and transportation. Biofuels were the topic of both fuel and additive producers, as well as colleagues from the faculty, approaching the subject from the aspect of application in vehicles. The subject has been topical globally, in Europe, and has been becoming so also in Croatia. European Comission has in 2003 passed the regulation 2003/30/EC on promoting biofuel use in transportation. Owing to the growth of the living standard, it is the traffic sector that records a constant increase of motor vehicles and motor fuels consumption. Key motivators of the European politicians in passing the regulation were: 1. seeking greater energy supply safety in Europe – freeing it in part from importing energy from oil-rich countries involved in constant war threats, 2. concern for agricultural development and management of excess agricultural products, in order to preserve workplaces in the agricultural sector, and 3. most of all concern for reducing the emission of greenhouse gases, in order to bring down the intensity of climatic changes

Laccase catalysed biotransformation of phenolic compounds performed in a microreactor in aqueous phase-organic solvent systems

Mikroreaktori sa svojim tipičnim dimenzijama mikrokanala u području 10 μm – 500 μm karakterizirani su mnogo većom međufaznom površinom u odnosu na konvencionalne reaktorske sustave. Posljedično se zbog ovoga ostvaruje intenzivniji prijenos tvari i topline što doprinosi povećanju konverzije te nastajanje manje količine sporednih produkata. Također su zbog malog reaktorskog volumna za provedbu eksperimenta potrebne male količine kemikalija. Osim ovoga upotrebom mikroreaktora povećavaju se doseg reakcije i sigurnost provedbe procesa. U ovom radu provedena je biotransformacija fenola enzimom lakaza porijeklom iz Trametes versicolor u mikroreaktoru. Konverzija i kinetički parametri jednosupstratne Michaelis-Menteničine kinetike procijenjeni u mikroreaktoru uspoređeni su s onima dobivenim pokusima provedenim u kotlastom reaktoru. Biotransformacija fenola provedena je u tri različita dvofazna sustava voda-organsko otapalo (diklormetan, heksan i toluen) pri čemu je enzim lakaza bio u vodenoj fazi, a fenol u organskom otapalu. U svakom od promatranih sustava provedena je analiza stabilnosti enzima lakaze. Za svaki od analiziranih sustava voda-organsko otapalo provedena je i analiza profila strujanja u mikrokanalu pri različitim protocima i omjerima vode i organskog otapala. Zaključeno je da je kod malih vrijednosti Reynoldsova broja do Re = 1,2 i kapilarnog broja do Ca = 1,3∙10-4 dominantno segmentirano strujanje, dok se kod Reynoldsovih brojeva većih od Re = 1,3 i kapilarnih brojeva većih od Ca = 2,1∙10-4 razvija paralelno strujanje. U šaržnom reaktoru postignute su sljedeće maksimalne konverzije: Xvoda-diklormetan = 28,49 %, Xvoda-heksan = 23,46 % i Xvoda-toulen = 32,79 % dok su u mikroreaktoru za vrijeme zadržavanja τ = 240 s postignute sljedeće konverzije: Xvoda-diklormetan = 79,28 %, Xvoda-heksan = 77,05 % i Xvoda-toulen = 79,28 %. Procijenjene vrijednosti maksimalnih brzina reakcije biotransformacije fenola enzimom lakaza u mikroreaktoru su približno 100 puta veće od onih procijenjenih u kotlastom reaktoru za pojedino otapalo. Kao najpogodnije otapalo za provedbu reakcije u kotlastom reaktoru i mikroreaktoru pokazao se toluen jer su u pokusima provedenim u sustavu voda-toluen procijenjeni najveća maksimalna brzina reakcije i najveći afinitet prema enzimu lakazi te je postignuta najveća konverzija.Microreactors with typical dimension of microchannels in range of 10 μm to500 μm are characterized with much greater interfacial area in comparison to conventional reactors. As a result there is much more intense mass and heat transfer what leads to larger conversions and smaller quantities of byproducts. Also, because of small reaction volume conducting the experiment requires small quantities of chemicals. Additionally, the use of microreactors increases conversion and process safety. In this work biotransformation of phenol using laccase from Trametes versicolor in a microreactor was performed. Conversion and kinetic parameter of single substrate Michaelis-Menten kinetics were estimated for microreactor experiments and compared with those obtained in a batch reactor. Biotransformation of phenol was conducted in three different two-phase systems water-organic solvent (dichloromethane, hexane, and toluene). Enzyme laccase was in aqueous phase and toluene in organic solvent. In every system analysis of laccase stability was performed. For every of the analyzed water-organic solvent systems flow patterns in microchannel with different flows and different water to organic solvent ratio were analyzed. It was concluded that in small Reynolds numbers up to Re = 1.2 and capillary numbers up to Ca = 1.3∙10-4 segmented flow patterns are dominant, while parallel profile is developed at Reynolds numbers larger than Re = 1.3 and capillary numbers larger than Ca = 2.1∙10-4 . In batch rector maximal conversion of Xwater-dichloromethane = 28.49 %, Xwater-hexane = 23.46 % and Xwater -toluene = 32.79 % were reached while in a microreactor for residence time τ = 240 s conversion of X water-dichloromethane = 79.28 %, X water-hexane = 77.05 % and Xwater-toluene = 79.28 % were reached. Values of estimated maximal reaction rate of laccase catalyzed phenol biotransformation were approximately 100 fold higher than ones estimated in a batch reactor for every solvent. Toluene was the most suitable solvent for the reaction in the batch and the microreactor because in performed experiments in water-toluene systems maximal reaction rate was estimated, the affinity of enzyme laccase was also maximal and consequently the maximal conversion was achieved

Diagnostic Accuracy of Ultrasound T-staging of the Urinary Bladder Cancer in Comparison with Histology in Elderly Patients

Urinary bladder cancer (UBC) is dominantly the cancer of the elderly occurring primarily in the 6th, 7th and 8th decade of life. The aim of this study was to evaluate diagnostic accuracy of ultrasound T-staging (UTS) of UBC in the group of elderly patients. In 152 elderly patients referred to transabdominal ultrasound examination in two different facilities (76 each) due to various symptoms (primarily painless gross or microscopic haematuria) UBC was diagnosed. Initial UTS at the moment of detection was performed and compared with fi nal histological T-staging (HTS). A high level of conformity between UTS and HTS was detected. In a total of 152 patients with UBC there were 115 (75.66%) patients with complete match between the UTS and HTS, 24 (15.79%) patients with minimal variation within one stage, and 13 (8.55%) patients with one stage difference between the UTS and HTS. The best result was established for the stage T1, where the accuracy was 94.5%. In other stages the accuracy was between 84.9% and 91.8%. The Youden’s index for all the stages was over 0.6. UTS has a high diagnostic accuracy, especially for stages T1 and T2. It is extremely useful tool in differentiating the superfi cial UBC from the muscle-invasive one, being of signifi cant importance in planning the further treatment of elderly patients and having important role in choosing appropriate surgical approach

Production of microreactor systems by additive manufacturing technology

Microreactor systems are reactors with three-dimensional structures which are under a millimeter in size. They are commonly fabricated by wet and dry etching, precision machining, laser treatment, blasting and lithographic tech- niques. Additive manufacturing technologies have been overlooked in this area. This paper presents a part of research related to fabrication of microstructured reactors (microreactors and millireactors) by using two additive manufac- turing technologies (fused filament fabrication and stereolithography). One example of static mixer used in a milli- reactor and one reactor designed for uniform droplet production are also presented

PRIKAZ RADA 39. STRUČNO-ZNANSTVENOG SIMPOZIJA GORIVA 2006

Osnovna poruka simpozija jest da hrvatske rafinerije danas kvalitetom motornih goriva zadovoljavaju zahtjeve proizvođača motornih vozila koja se kreću u Hrvatskoj. Završetkom modernizacije rafinerija do 2009. godine proizvodnja motornih goriva bit će usklađena s uvjetima koji će tada biti obvezni u Europskoj uniji

Efficacy of a fixed combination of insulin degludec and GLP-1 receptor agonist liraglutide (Xultophy) in patient with type 2 diabetes

The fixed combination of insulin degludec and liraglutide- Xultophy is a newer therapy available for treatment of type 2 diabetes (DM2). Insulin degludec is an ultralong-basal insulin analogue and liraglutide is a glucagon-like peptide-1 receptor agonist. In this case we monitor values of HbA1c as a marker of glycemia regulation and predictor of vascular incidents, but also fasting glucose, HDL, LDL and triglycerides were observed

Glycemic Control in Diabetes Type 2 Patients in Foster Families of Brod-Posavina County During the COVID-19 Pandemic

COVID-19 pandemic has changed everyday life and medical supervision of chronically ill patients. Epidemiological measures, social distancing, and limited access to medical care impair glycemic control in patients with diabetes. Also, type 2 diabetes is a risk factor for more severe form of coronavirus disease. A large proportion of diabetic patients are placed in foster families who also adapt to the new situation. The purpose of this study was to examine the manner and frequency of glycemic control in patients with type 2 diabetes who are placed in foster families in the region of Brod- Posavina County. We established contact with patients suffering from type 2 diabetes situated in foster families and their caregivers. Measurement of glycemia was performed several times a day with regular notes and the data were supplemented by an insight into the medical documentation of patients in the hospital information system. The study included 33 patients with type 2 diabetes. The relationship between HbA1C with fasting and postprandial glycemia was linear. There were no statistically significant differences in HbA1C regulation by type of therapy. There was a significant difference in the number of complications according to the level of HbA1C (Hi square test = 25.982, p <.001). The number of complications generally increased as HbA1C regulation was poorer. During current COVID-19 pandemic, care for patients with type 2 diabetes is significantly limited. Improved medical care for patients can be achieved by establishing cooperation and daily communication between caregivers, family physicians and, if necessary, diabetologists, especially through the use of online platforms and telephone communication, all with the aim of early detection of diabetes complications and adequate treatment of patients in current conditions

Glycemic and Extraglycemic Effects of Metformin in Patients with Diabetes

For several decades, metformin has been the mainstay of treatment of type 2 diabetes (T2D), not only due to its remarkable efficacy in both monotherapy and combination therapy regimens, but also due to its favorable safety profile, weight neutrality, and low cost. Other advantages have been reported, including improvements in lipid profile and inflammatory markers and reports of cardioprotective effects, albeit with scant evidence. The modification of the cellular energy metabolism is the core of metformin’s mode of action. Metformin works to lower serum glucose concentration by inhibiting hepatic gluconeogenesis and countering the action of glucagon. Secondarily, it enhances glucose uptake in peripheral tissues, predominantly in the muscles. Long-term and widespread use of metformin has shed light on its other potential uses mediated by its effects on deranged metabolic pathways. Moreover, metformin is gaining research interest by demonstrating its potential in the treatment of multiple disorders other than diabetes and has been proven to have anti-cancer, immunoregulatory, and anti-aging properties. As a result, metformin is currently being researched as a potential treatment option for various diseases