Ocjena primjenjivosti frikcijskih pumpi u ljudskom krvotoku

U ovom radu opisana je problematika i proračunavane su radne karakteristike srčanih pumpi. U uvodnom poglavlju opisana je opća problematika modernog društva vezanog za srčane bolesti i rastuća potreba za srčanim pumpama koje će pružiti potporu srcu, ili ga u potpunosti zamijeniti. U prvom poglavlju je opisana krv i njezine karakteristike, kao i problemi koji su vezani uz krv. Također su opisani mehanizmi hemolize i tromboze, temeljem koje su definirani kriteriji za rad pumpi (dopušteno područje smičnih naprezanja i indeks oštećenja crvenih krvnih zrnaca). U drugom poglavlju je opisano srce i njegov rad. Isto tako su analizirane srčane pumpe koje se koriste u praksi.U nastavku rada definiranoje radno područje srčane pumpe na temelju fizioloških podataka vezanih uz stvarno srce. Za dva tipa frikcijskih pumpi: cilindrične frikcijske pumpe i frikcijske pumpe s rotirajućim diskom su izvedeni analitički izrazi koji povezuju prirast tlaka i protok kroz pumpu, te definiraju potrebnu snagu za pogon pumpe, te minimalna i maksimalna smična naprezanja, stupanj korisnosti pumpe i indeks oštećenja crvenih krvnih stanica. Definirane su dvije vrste dijagrama: jedni koji služe za izbor pumpe (gabarita i brzine vrtnje), a drugi za analizu karakteristike odabrane pumpe (zadanih gabarita) u zadanom radnom području. Usporedbom dvaju pumpi zaključilo se da bi pumpa s rotirajućim diskom bila povoljnija, ali taj bi zaključak bilo nužno provjeriti kroz numeričko rješavanje potpunih Navier-Stokesovih jednadžbi koje opisuju strujanje kroz ove dvije pumpe, budući da je korišteno analitičko rješenje za pumpu s rotirajućim diskom vjerojatno fizikalno nerealno, zbog pretpostavki koje je bilo nužno uvesti da bi se rješenje moglo naći

Otpornost na eroziju brzoreznog čelika PM S390 MC

U ovom radu opisana je problematika trošenja brzoreznog čelika. U uvodu su opisani mehanizmi trošenja erozijom, kao i parametri koji utječu na erozijsko trošenje. \Nakon opisa trošenja erozijom slijedi opis brzoreznih čelika, kao i mikrostruktura, toplinske obrade volumena, te nitriranje i kakav učinak te obrade imaju na mikrostrukturu i fizikalna svojstva brzoreznog čelika, naročito otpornost na trošenje. U eksperimentalnom dijelu je opisano ispitivanje uzoraka brzoreznog čelika PM S390 MC, te su dijagramski prezentirani rezultati dobiveni ispitivanjima uzorka erozivnom djelovanju čestica pod kutovima 90° i 30°, i dvjema različitim vrstama erozivnih čestica

Assesment of applicability of friction pumps in human circulatory system

U ovom radu opisana je problematika i proračunavane su radne karakteristike srčanih pumpi. U uvodnom poglavlju opisana je opća problematika modernog društva vezanog za srčane bolesti i rastuća potreba za srčanim pumpama koje će pružiti potporu srcu, ili ga u potpunosti zamijeniti. U prvom poglavlju je opisana krv i njezine karakteristike, kao i problemi koji su vezani uz krv. Također su opisani mehanizmi hemolize i tromboze, temeljem koje su definirani kriteriji za rad pumpi (dopušteno područje smičnih naprezanja i indeks oštećenja crvenih krvnih zrnaca). U drugom poglavlju je opisano srce i njegov rad. Isto tako su analizirane srčane pumpe koje se koriste u praksi.U nastavku rada definiranoje radno područje srčane pumpe na temelju fizioloških podataka vezanih uz stvarno srce. Za dva tipa frikcijskih pumpi: cilindrične frikcijske pumpe i frikcijske pumpe s rotirajućim diskom su izvedeni analitički izrazi koji povezuju prirast tlaka i protok kroz pumpu, te definiraju potrebnu snagu za pogon pumpe, te minimalna i maksimalna smična naprezanja, stupanj korisnosti pumpe i indeks oštećenja crvenih krvnih stanica. Definirane su dvije vrste dijagrama: jedni koji služe za izbor pumpe (gabarita i brzine vrtnje), a drugi za analizu karakteristike odabrane pumpe (zadanih gabarita) u zadanom radnom području. Usporedbom dvaju pumpi zaključilo se da bi pumpa s rotirajućim diskom bila povoljnija, ali taj bi zaključak bilo nužno provjeriti kroz numeričko rješavanje potpunih Navier-Stokesovih jednadžbi koje opisuju strujanje kroz ove dvije pumpe, budući da je korišteno analitičko rješenje za pumpu s rotirajućim diskom vjerojatno fizikalno nerealno, zbog pretpostavki koje je bilo nužno uvesti da bi se rješenje moglo naći.This paper describes the issues and calculated the performance of the heart pumps. The introductory chapter describes the general problems of modern society related to heart disease and a growing need for cardiac pumps that will support the heart, or completely replaced it. The first chapter describes the blood and its characteristics, as well as problems related to blood. It also describes mechanisms of hemolysis and thrombosis, which are based on defined criteria for the operation of the pump (permissible area of the shear stress and damage index of red blood cells). The second chapter describes the heart and how it works. Heart pumps that are used in practice are also analyzed in this chapter. Further in this work working fieldof heart pump is defined based on physiological data related to the actual heart. For two types of friction pumps: cylindrical friction pump and friction pump with rotating disc are derived by analytical expressions that connect the growth pressure and flow through the pump, define the power required to drive the pump, the minimum and maximum shear stress, efficiency pump and damage index of red blood cells. There are two types of diagrams defined: one that is used for selection of the pump (size and speed), and the second to analyze the characteristics of the selected pump (of selected dimensions) in the default working field. Comparing the two pump types it was found that pump with a rotating disc was favorable, but it would be necessary to check this conclusion with complete numerical solution of the Navier-Stokes equations for the flow through the two pumps, since the used analytical solution of a pump with a rotating disc is probably physically unrealistic, because of the introduction of assumptions that was necessary to find a solution

Cycling Corridors in the Republic of Croatia

Današnje poimanje biciklizma kao aktivnosti je nešto što za sve veći broj ljudi donosi slobodu i pustolovinu, bijeg od svakidašnjeg ritma, sredstvo za opuštanje i mentalno i fizičko ozdravljenje. Sve više osoba koristi bicikl kao glavno sredstvo za razgledavanje svijeta oko sebe. Bicikl je kao prijevozno sredstvo iznimno učinkovit: utrošak energije je malen, omogućuje fizičku aktivnost, ne ovisi o dostupnosti ili cijeni energenata i ne stvaraju buku ili zagađenje. Posebno su pogodni u urbanim krajevima gdje se korištenjem bicikla smanjuju prometne gužve i problemi s parkiranjem. U radu se prikazuje sadašnje stanje cikloturizma na području Ličko-senjske županije te se analiziraju daljnje mogućnosti razvoja cikloturizma na tom području. Cikloturizam spada u rastuće oblike turističke aktivnosti i predstavlja jedan od turističkih proizvoda sa najvećom perspektivom razvoja. Ličko-senjska županija bogata je prirodnim i antropogenim turističkim resursima koji privlače velik broj turista. U praktičnom dijelu rada opisuju se biciklističke rute na području Ličko-senjske županije. Svaka od ruta nudi svoj specifičan doživljaj upotpunjen ugostiteljskom ponudom. Rute uglavnom prate manje prometne lokalne ceste, a prolaze predivnim krajolicima i dotiču vrijednu povijesno kulturnu baštinu. Potencijal za razvoj cikloturizma u Ličko-senjskoj županiji je velik, a proizlazi iz značajki prostora, odnosno atrakcijske osnove županije. Razvoj biciklističkog prometa planiran je u strateškim dokumentima Republike Hrvatske i Europske unije, koji određuju dugoročne razvojne ciljeve te mjere i aktivnosti za ostvarivanje tih ciljeva, kao jedne od mjera za očuvanje zdravlja stanovništva i okoliša. Između ostalog želi se potaknuti razvoj biciklističkog prometa i povećati udio vozača bicikala u svakodnevnom prometu obuhvativši sve čimbenike koji mogu doprinijeti stvaranju uvjeta za održiv, zdrav i siguran način kretanja biciklom i povećati broj putovanja biciklom ostvarujući pritom dostupnost razvojem biciklističke infrastrukture, poboljšavajući sigurnost vozača bicikala, osiguravajući prostor za odlaganje i sigurnost bicikala i opreme, mijenjajući svijest o vožnji bicikla kao poželjnom načinu prometovanja te osiguravajući financijska sredstva za ostvarenje ovih ciljeva.Today's understanding of cycling as an activity is something that for an increasing number of people brings freedom and adventure, escape from everyday rhythm, a means of relaxation and mental and physical healing. More and more people use the bicycle as the main means of sightseeing around the world. The bicycle is extremely efficient as a means of transport: energy consumption is low, it allows physical activity, does not depend on availability or cost of energy sources and does not create noise or pollution. They are particularly suitable in urban areas where bicycle use reduces traffic jams and parking problems. This paper presents the present state of cyclotourism in the Ličko-Senjska County and analyzes further possibilities of cyclotourism development in this area. Cyclotourism is part of the growing forms of tourist activity and is one of the tourism products with the greatest prospect of development. Ličko-Senjska County is rich in natural and anthropogenic tourism resources attracting a large number of tourists. In the practical part of the work, cycling routes are described in the Ličko-Senjska County. Each of the routes offers its specific experience complemented by a catering offer. Routes mostly follow less busy local roads, and pass through beautiful landscapes and touch on valuable historic cultural heritage. The potential for cyclotourism development in Ličko-Senjska County is great, and it derives from the features of the area, ie the county's attractions. The development of bicycle traffic is planned in the strategic documents of the Republic of Croatia and the European Union, which determine the long-term development goals and measures and activities for achieving these goals as one of the measures to preserve the health of the population and the environment. Among other things, it wants to encourage the development of bicycle traffic and increase the proportion of bicycle drivers in daily traffic, including all factors that can contribute to the creation of conditions for a sustainable, healthy and safe way of cycling and to increase the number of bicycle trips, thereby achieving the availability of bicycling infrastructure, providing storage space and safety for bicycles and equipment, changing the awareness of bicycle driving as a preferred mode of transport and providing financial means for achieving these goals

Cycling Corridors in the Republic of Croatia

Današnje poimanje biciklizma kao aktivnosti je nešto što za sve veći broj ljudi donosi slobodu i pustolovinu, bijeg od svakidašnjeg ritma, sredstvo za opuštanje i mentalno i fizičko ozdravljenje. Sve više osoba koristi bicikl kao glavno sredstvo za razgledavanje svijeta oko sebe. Bicikl je kao prijevozno sredstvo iznimno učinkovit: utrošak energije je malen, omogućuje fizičku aktivnost, ne ovisi o dostupnosti ili cijeni energenata i ne stvaraju buku ili zagađenje. Posebno su pogodni u urbanim krajevima gdje se korištenjem bicikla smanjuju prometne gužve i problemi s parkiranjem. U radu se prikazuje sadašnje stanje cikloturizma na području Ličko-senjske županije te se analiziraju daljnje mogućnosti razvoja cikloturizma na tom području. Cikloturizam spada u rastuće oblike turističke aktivnosti i predstavlja jedan od turističkih proizvoda sa najvećom perspektivom razvoja. Ličko-senjska županija bogata je prirodnim i antropogenim turističkim resursima koji privlače velik broj turista. U praktičnom dijelu rada opisuju se biciklističke rute na području Ličko-senjske županije. Svaka od ruta nudi svoj specifičan doživljaj upotpunjen ugostiteljskom ponudom. Rute uglavnom prate manje prometne lokalne ceste, a prolaze predivnim krajolicima i dotiču vrijednu povijesno kulturnu baštinu. Potencijal za razvoj cikloturizma u Ličko-senjskoj županiji je velik, a proizlazi iz značajki prostora, odnosno atrakcijske osnove županije. Razvoj biciklističkog prometa planiran je u strateškim dokumentima Republike Hrvatske i Europske unije, koji određuju dugoročne razvojne ciljeve te mjere i aktivnosti za ostvarivanje tih ciljeva, kao jedne od mjera za očuvanje zdravlja stanovništva i okoliša. Između ostalog želi se potaknuti razvoj biciklističkog prometa i povećati udio vozača bicikala u svakodnevnom prometu obuhvativši sve čimbenike koji mogu doprinijeti stvaranju uvjeta za održiv, zdrav i siguran način kretanja biciklom i povećati broj putovanja biciklom ostvarujući pritom dostupnost razvojem biciklističke infrastrukture, poboljšavajući sigurnost vozača bicikala, osiguravajući prostor za odlaganje i sigurnost bicikala i opreme, mijenjajući svijest o vožnji bicikla kao poželjnom načinu prometovanja te osiguravajući financijska sredstva za ostvarenje ovih ciljeva.Today's understanding of cycling as an activity is something that for an increasing number of people brings freedom and adventure, escape from everyday rhythm, a means of relaxation and mental and physical healing. More and more people use the bicycle as the main means of sightseeing around the world. The bicycle is extremely efficient as a means of transport: energy consumption is low, it allows physical activity, does not depend on availability or cost of energy sources and does not create noise or pollution. They are particularly suitable in urban areas where bicycle use reduces traffic jams and parking problems. This paper presents the present state of cyclotourism in the Ličko-Senjska County and analyzes further possibilities of cyclotourism development in this area. Cyclotourism is part of the growing forms of tourist activity and is one of the tourism products with the greatest prospect of development. Ličko-Senjska County is rich in natural and anthropogenic tourism resources attracting a large number of tourists. In the practical part of the work, cycling routes are described in the Ličko-Senjska County. Each of the routes offers its specific experience complemented by a catering offer. Routes mostly follow less busy local roads, and pass through beautiful landscapes and touch on valuable historic cultural heritage. The potential for cyclotourism development in Ličko-Senjska County is great, and it derives from the features of the area, ie the county's attractions. The development of bicycle traffic is planned in the strategic documents of the Republic of Croatia and the European Union, which determine the long-term development goals and measures and activities for achieving these goals as one of the measures to preserve the health of the population and the environment. Among other things, it wants to encourage the development of bicycle traffic and increase the proportion of bicycle drivers in daily traffic, including all factors that can contribute to the creation of conditions for a sustainable, healthy and safe way of cycling and to increase the number of bicycle trips, thereby achieving the availability of bicycling infrastructure, providing storage space and safety for bicycles and equipment, changing the awareness of bicycle driving as a preferred mode of transport and providing financial means for achieving these goals

BEHAVIOUR ANALYSIS OF TRAFFIC PARTICIPANTS AT LEVEL CROSSINGS

Sa stajališta sigurnosti željezničko-cestovni prijelaz (ŽCP) kao mjesto neposrednog sučeljavanja željezničkog i cestovnog prometa točka je visokog rizika. Namjerno ili nenamjerno rizično ponašanje korisnika ŽCP-a glavni je uzrok izvanrednih događaja. Cilj ovoga rada jest utvrditi uzroke nepropisnog prelaženja pješaka i biciklista preko ŽCP-a te predložiti mjere prevencije. Istraživanjem se željelo utvrditi u kojim će situacijama pješaci i biciklisti nepropisno prelaziti preko pruge. Kako će na poštivanje prometnih propisa utjecati prisustvo službene osobe? Kako na poštivanje propisa utječe videonadzor? Utječu li edukativne kampanje na promjenu obrazaca ponašanja korisnika ŽCP-a? U ovome je istraživanju prvi su put primjenjivani kontinuirano videosnimanje i promatranje ponašanja korisnika željezničko-cestovnih prijelaza te anketno istraživanje, a u cilju utvrđivanja ponašanja sudionika u prometu na ŽCP-ima. Metodologija istraživanja primjenjena je na ŽCP-u Republike Austrije.From the aspect of traffic safety, level crossings (LC) are areas with increased risk for severe accidents. Intentional or unintentional risky behaviour of level crossing users is the main cause for all accidents. The main objective of this study is to determine the reasons for illegal pedestrian and cyclist crossing over LC and accordingly propose prevention measures. The study aim is to identify in which situations will pedestrians and cyclists illegally cross the tracks. How to road users affected by the presence of officials? How to road users affected by the presence of video surveillance? Do the educational campaigns can change behavior patterns of LC users? This is the first time for using survey and video surveillance for studying, describing and analysing correlation of nonmotorized LC users behaviour and TS on Croatian LCs. Research metodology is applyed on LC Republike Austrije

Survey-based Impact of Influencing Parameters on Level Crossings Safety

Level crossing (LC) accidents are a significant safety challenge worldwide and for that reason they have been subject of numerous research activities. Joint conclusion is that human behaviour is the main cause of accidents. This study examines how and to which extent certain influential parameters cause accident mechanisms on level crossings. To gain the necessary data we used an on-line survey questionnaire that was sent internationally to key experts in the field of road and railway safety. A total of 185 experts were asked to rank how much certain parameters influence level crossings accident mechanisms and what are the best countermeasures for diminishing accidents at level crossings. To our knowledge, this is the first time that an international survey among key experts was used to gain necessary data about influential parameters regarding level crossings safety. The results of this study could be used by road and railway traffic engineers and policy makers for further enhancement of LC’s safety.</p

Experimental and Computational Study of the Antioxidative Potential of Novel Nitro and Amino Substituted Benzimidazole/Benzothiazole-2- Carboxamides with Antiproliferative Activity

We present the synthesis of a range of benzimidazole/benzothiazole-2-carboxamides with a variable number of methoxy and hydroxy groups, substituted with nitro, amino, or amino protonated moieties, which were evaluated for their antiproliferative activity in vitro and the antioxidant capacity. Antiproliferative features were tested on three human cancer cells, while the antioxidative activity was measured using 1, 1- diphenyl-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing/antioxidant power (FRAP) assays . Trimethoxy substituted benzimidazole-2-carboxamide 8 showed the most promising antiproliferative activity (IC50 = 0.6– 2.0 µM), while trihydroxy substituted benzothiazole-2-carboxamide 29 was identified as the most promising antioxidant, being significantly more potent than the reference butylated hydroxytoluene BHT in both assays. Moreover, the latter also displays antioxidative activity in tumor cells. The measured antioxidative capacities were rationalized through density functional theory (DFT) calculations, showing that 29 owes its activity to the formation of two [O•∙∙∙H–O] hydrogen bonds in the formed radical. Systems 8 and 29 were both chosen as lead compounds for further optimization of the benzazole-2-carboxamide scaffold in order to develop more efficient antioxidants and/or systems with the antiproliferative activit

Oxytetracycline hyper-production through targeted genome reduction of Streptomyces rimosus

Most biosynthetic gene clusters (BGC) encoding the synthesis of important microbial secondary metabolites, such as antibiotics, are either silent or poorly expressed; therefore, to ensure a strong pipeline of novel antibiotics, there is a need to develop rapid and efficient strain development approaches. This study uses comparative genome analysis to instruct rational strain improvement, using Streptomyces rimosus, the producer of the important antibiotic oxytetracycline (OTC) as a model system. Sequencing of the genomes of two industrial strains M4018 and R6-500, developed independently from a common ancestor, identified large DNA rearrangements located at the chromosome end. We evaluated the effect of these genome deletions on the parental S. rimosus Type Strain (ATCC 10970) genome where introduction of a 145 kb deletion close to the OTC BGC in the Type Strain resulted in massive OTC overproduction, achieving titers that were equivalent to M4018 and R6-500. Transcriptome data supported the hypothesis that the reason for such an increase in OTC biosynthesis was due to enhanced transcription of the OTC BGC and not due to enhanced substrate supply. We also observed changes in the expression of other cryptic BGCs; some metabolites, undetectable in ATCC 10970, were now produced at high titers. This study demonstrated for the first time that the main force behind BGC overexpression is genome rearrangement. This new approach demonstrates great potential to activate cryptic gene clusters of yet unexplored natural products of medical and industrial value

Hydroxybenzothiazoles as New Nonsteroidal Inhibitors of 17β-Hydroxysteroid Dehydrogenase Type 1 (17β-HSD1)

17β-estradiol (E2), the most potent estrogen in humans, known to be involved in the development and progession of estrogen-dependent diseases (EDD) like breast cancer and endometriosis. 17β-HSD1, which catalyses the reduction of the weak estrogen estrone (E1) to E2, is often overexpressed in breast cancer and endometriotic tissues. An inhibition of 17β-HSD1 could selectively reduce the local E2-level thus allowing for a novel, targeted approach in the treatment of EDD. Continuing our search for new nonsteroidal 17β-HSD1 inhibitors, a novel pharmacophore model was derived from crystallographic data and used for the virtual screening of a small library of compounds. Subsequent experimental verification of the virtual hits led to the identification of the moderately active compound 5. Rigidification and further structure modifications resulted in the discovery of a novel class of 17β-HSD1 inhibitors bearing a benzothiazole-scaffold linked to a phenyl ring via keto- or amide-bridge. Their putative binding modes were investigated by correlating their biological data with features of the pharmacophore model. The most active keto-derivative 6 shows IC50-values in the nanomolar range for the transformation of E1 to E2 by 17β-HSD1, reasonable selectivity against 17β-HSD2 but pronounced affinity to the estrogen receptors (ERs). On the other hand, the best amide-derivative 21 shows only medium 17β-HSD1 inhibitory activity at the target enzyme as well as fair selectivity against 17β-HSD2 and ERs. The compounds 6 and 21 can be regarded as first benzothiazole-type 17β-HSD1 inhibitors for the development of potential therapeutics