Influence of chlorides on corrosion resistance of stainless steels in water

Korozijski postojani čelici imaju iz dana u dan sve veću primjenu u suvremenoj proizvodnji, jer se područje njihove uporabe sve više proširuje.Koriste se sve više i u građevinarstvu, nautici, brodogradnji, itd. Predstavljaju jednu od najvažnijih skupina konstrukcijskih postojanih materijala. Istodobno ovi konstrukcijski materijali u određenim uvjetima postaju vrlo skloni posebno lokalnim korozijskim oštećenjima. U teorijskom dijelu prikazana je podjela nehrđajućih čelika. Također je opisana korozijska postojanost nehrđajućih čelika te čimbenici koji utječu na korozijsku postojanost. Opisani su svi mehanizmi korozije, a posebno je obrađena problematika nastanka rupičaste korozije, te utjecaj vanjskih faktora na mehanizam rupičaste korozije. Poseban naglasak je dan na utjecaj promjene udjela klorida u vodenim otopinama na pojavu rupičaste korozije. U eksperimentalnom dijelu rada provedena su elektrokemijska korozijska ispitivanja utjecaja klorida na korozijsku postojanost nehrđajućih čelika. U ispitivanjima su korišteni austenitni nehrđajući čelici AISI 321, AISI 316L i UNS S31050, te duplex čelik AISI 2304 i superduplex nehrđajući čelik AISI 2507 koji su ispitivani u vodama sa različitim udjelima klorida (50 ppm Cl - , 1900 ppm Cl - te19000 ppm Cl - ) te su određeni elektrokemijski korozijski parametri. Nakon eksperimentalnog dijela analizirani su rezultati, te je na temelju rezultata izveden zaključak.Corrosion resistant steels have been increasingly used in modern manufacturing day by day, as their use area is increasingly expanding. They are increasingly used in construction, nautical, shipbuilding, etc. They represent one of the most important groups of structure corrosion resistant materials. At the same time these materials become very prone to local corrosion damage in certain conditions. The theoretical part shows the various types of stainless steels. The corrosion resistance of stainless steel and the factors that influence corrosion resistance are also described as well as corrosionmechanisms. Special emphasis was given on the problems of the pitting corrosion, as well as the influence of external factors on the perforation corrosion mechanism. Particular emphasis was given to the effect of changing the chloride content in aqueous solutions on occurrence of pitting corrosion. In the experimental part, electrochemical corrosion tests have been carried out on chloride corrosion on the corrosion resistance of stainless steels. Austenitic stainless steels AISI 321 and AISI 316L, supeaustenitic stainless steel UNS S31050, duplex stainless steel AISI 2304 and superduplex stainless steel AISI 2507 steel were tested in in waters with different chloride contents (50 ppm CI - , 1900 ppm CI - and 19000 ppm CI - )and electrochemical corrosion parameters were defined. After the experimental part, the results were analyzed and based on the results the conclusion was drawn

Animal migrations

Migracije životinja su kretanja pojedinih životinja na relativno velike udaljenosti, obično na sezonskoj osnovi. Migracija je pojava koju dijele gotovo sve vrste životinja, ribe, sisavci, ptice, pa i ljudi. Teško je pronaći neku životinjsku vrstu koja to ne čini, pa čak i u nekim razvojnim stadijima dok još ne dosegnu razinu odrasle jedinke. Životinje putuju u sve krajeve svijeta kako bi pronašle hranu ili pogodnije klimatske uvjete za svoj opstanak. Ovaj primarni instinkt za preživljavanjem i produljenjem vrste tjera ih na teške i veoma dugačke putove. Jedini razlog za migracije je taj što prednosti udaljenog putovanja višestruko nadmašuju uloženi trud i gubitke koji se dogode na putovanju. Ptice su jedna od tri skupine životinja koja je razvila sposobnost aktivnog leta. Ptice su poznate po svojim dnevnim, godišnjim ili sezonskim migracijama. U radu su opisane anatomske i fiziološke prilagodbe ptica na let te prilagodbe ponašanja za vrijeme migracija.Animal migration is the movement of individual animals over relatively long distances, usually on a seasonal basis. Migration is a phenomenon shared by virtually all species of animals, fish, mammals, birds, and even humans. It is difficult to find an animal species that does not do it, even in some developmental stages, until it reaches the adulthood. Animals all over the world travel to find food or better climactic conditions for their survival. This primary instinct for survival and prolongation of the species is what drives them to difficult and very long journeys. The only reason for migration is that the benefits of distance travel are many times greater than the efforts and losses that occur on the journey. Birds are one of three groups of animals that have developed the ability of an active flight. Birds are known for their daily, annually or seasonal migrations. The paper describes anatomical and physiological adaptations of bird’s flight and behavioural adaptation during migrations

Utjecaj morfologije druza na sloj fotoreceptora u senilnoj makularnoj degeneraciji [Influence of drusen morphology on disruption of photoreceptor layer in age-related macular degeneration]

INTRODUCTION: Age related macular degeneration (ARMD) is progressive neurodegenerative disease and one of the major causes of irreversible vision loss in developed countries. Dry form of ARMD is characterized with presence of abnormal pigment changes and drusen in macula which may lead to decrease in vision quality. Drusen are made of extracellular material situated between Bruch membrane and retinal pigment epithelium. With their position and growth they cause disturbance in their surroundings. OCT enables insight in drusen morphology as well in morphology of surrounding structures, first of all photoreceptors and retinal pigment epithelium. Although many papers that confirm presence of outer nuclear photoreceptor layer atrophy and atrophy of ellipsoid zone above drusen have been published, so far the relation between drusen morphology and photoreceptor atrophy has not been established. AIM OF STUDY: To determine which morphologic characteristics of drusen are related to photoreceptor atrophy as well to establish progression of photoreceptor atrophy in 2 years interval MATERALS AND METHOD: In this prospective study we analyzed and compared OCT scans of 44 eyes patients having dry drusiform ARMD in 2 years period. We used Optopol Copernicus 6x6 milimeter 3D scan of macular area. In every OCT scan we analyzed all drusen for their: number, shape, reflectivity, homogeneity, outer nuclear layer thickness, height, width, and central retinal thickness (CRT). RESULTS: Comparison of number of drusen related to photoreceptor atrophy on the beginning and the end of study revealed that there is statistically significant increase of drusen related to photoreceptor atrophy in 2 years period. On the other hand, decrease of drusen number not related to photoreceptor atrophy was noticed in the same period. Analysis of drusen height to ellipsoid zone and outer nuclear layer atrophy showed that the higher are the drusen the more significant atrophy above drusen exists. Analysis of drusen width to ellipsoid zone and outer nuclear layer atrophy showed that the wider are the drusen the more significant atrophy above drusen exists. Very interesting result occurred when we compared the eyes in which there was increase in number of drusen related to photoreceptor atrophy in to 2 years period to the eyes in which those kind of drusen were not present. The results showed, that eyes in which increase of drusen number related to photoreceptor atrophy was present, had statically higher values of CRT, average height and total drusen number. CONCLUSION: Interpretation of OCT scans in patients having drusiform ARMD should not be limited only to confirmation of dry form of disease or excluding wet form of disease. Every patient, after being diagnosed with certain disease is interested in their prognosis. Results of this study enable individual interpretation of drusen morphologic characteristics and provide more precise evaluation of stage and progression of disease for individual patient diagnosed with dry ARMD. With duration of dry ARMD there is increase of drusen number related to photoreceptor atrophy. The higher and wider in average the drusen are, the photoreceptor atrophy is more pronounced. Patients having higher total drusen number, higher average drusen height and higher CRT value have more chance for increase of drusen related to photoreceptor atrophy in period of 2 years and therefore probably more chance for vision deterioration

Animal migrations

Migracije životinja su kretanja pojedinih životinja na relativno velike udaljenosti, obično na sezonskoj osnovi. Migracija je pojava koju dijele gotovo sve vrste životinja, ribe, sisavci, ptice, pa i ljudi. Teško je pronaći neku životinjsku vrstu koja to ne čini, pa čak i u nekim razvojnim stadijima dok još ne dosegnu razinu odrasle jedinke. Životinje putuju u sve krajeve svijeta kako bi pronašle hranu ili pogodnije klimatske uvjete za svoj opstanak. Ovaj primarni instinkt za preživljavanjem i produljenjem vrste tjera ih na teške i veoma dugačke putove. Jedini razlog za migracije je taj što prednosti udaljenog putovanja višestruko nadmašuju uloženi trud i gubitke koji se dogode na putovanju. Ptice su jedna od tri skupine životinja koja je razvila sposobnost aktivnog leta. Ptice su poznate po svojim dnevnim, godišnjim ili sezonskim migracijama. U radu su opisane anatomske i fiziološke prilagodbe ptica na let te prilagodbe ponašanja za vrijeme migracija.Animal migration is the movement of individual animals over relatively long distances, usually on a seasonal basis. Migration is a phenomenon shared by virtually all species of animals, fish, mammals, birds, and even humans. It is difficult to find an animal species that does not do it, even in some developmental stages, until it reaches the adulthood. Animals all over the world travel to find food or better climactic conditions for their survival. This primary instinct for survival and prolongation of the species is what drives them to difficult and very long journeys. The only reason for migration is that the benefits of distance travel are many times greater than the efforts and losses that occur on the journey. Birds are one of three groups of animals that have developed the ability of an active flight. Birds are known for their daily, annually or seasonal migrations. The paper describes anatomical and physiological adaptations of bird’s flight and behavioural adaptation during migrations

Utjecaj klorida na korozijsku postojanost nehrđajućih čelika u vodi

Korozijski postojani čelici imaju iz dana u dan sve veću primjenu u suvremenoj proizvodnji, jer se područje njihove uporabe sve više proširuje.Koriste se sve više i u građevinarstvu, nautici, brodogradnji, itd. Predstavljaju jednu od najvažnijih skupina konstrukcijskih postojanih materijala. Istodobno ovi konstrukcijski materijali u određenim uvjetima postaju vrlo skloni posebno lokalnim korozijskim oštećenjima. U teorijskom dijelu prikazana je podjela nehrđajućih čelika. Također je opisana korozijska postojanost nehrđajućih čelika te čimbenici koji utječu na korozijsku postojanost. Opisani su svi mehanizmi korozije, a posebno je obrađena problematika nastanka rupičaste korozije, te utjecaj vanjskih faktora na mehanizam rupičaste korozije. Poseban naglasak je dan na utjecaj promjene udjela klorida u vodenim otopinama na pojavu rupičaste korozije. U eksperimentalnom dijelu rada provedena su elektrokemijska korozijska ispitivanja utjecaja klorida na korozijsku postojanost nehrđajućih čelika. U ispitivanjima su korišteni austenitni nehrđajući čelici AISI 321, AISI 316L i UNS S31050, te duplex čelik AISI 2304 i superduplex nehrđajući čelik AISI 2507 koji su ispitivani u vodama sa različitim udjelima klorida (50 ppm Cl - , 1900 ppm Cl - te19000 ppm Cl - ) te su određeni elektrokemijski korozijski parametri. Nakon eksperimentalnog dijela analizirani su rezultati, te je na temelju rezultata izveden zaključak

Animal migrations

Migracije životinja su kretanja pojedinih životinja na relativno velike udaljenosti, obično na sezonskoj osnovi. Migracija je pojava koju dijele gotovo sve vrste životinja, ribe, sisavci, ptice, pa i ljudi. Teško je pronaći neku životinjsku vrstu koja to ne čini, pa čak i u nekim razvojnim stadijima dok još ne dosegnu razinu odrasle jedinke. Životinje putuju u sve krajeve svijeta kako bi pronašle hranu ili pogodnije klimatske uvjete za svoj opstanak. Ovaj primarni instinkt za preživljavanjem i produljenjem vrste tjera ih na teške i veoma dugačke putove. Jedini razlog za migracije je taj što prednosti udaljenog putovanja višestruko nadmašuju uloženi trud i gubitke koji se dogode na putovanju. Ptice su jedna od tri skupine životinja koja je razvila sposobnost aktivnog leta. Ptice su poznate po svojim dnevnim, godišnjim ili sezonskim migracijama. U radu su opisane anatomske i fiziološke prilagodbe ptica na let te prilagodbe ponašanja za vrijeme migracija.Animal migration is the movement of individual animals over relatively long distances, usually on a seasonal basis. Migration is a phenomenon shared by virtually all species of animals, fish, mammals, birds, and even humans. It is difficult to find an animal species that does not do it, even in some developmental stages, until it reaches the adulthood. Animals all over the world travel to find food or better climactic conditions for their survival. This primary instinct for survival and prolongation of the species is what drives them to difficult and very long journeys. The only reason for migration is that the benefits of distance travel are many times greater than the efforts and losses that occur on the journey. Birds are one of three groups of animals that have developed the ability of an active flight. Birds are known for their daily, annually or seasonal migrations. The paper describes anatomical and physiological adaptations of bird’s flight and behavioural adaptation during migrations

Valorization of the newly discovered European snake-eyed skink population (Ablepharus kitaibelii) on Stinice, Papuk Mountain in Croatia

The European snake-eyed skink (Ablepharus kitaibelii) is an endangered lizard species in Croatia, limited to a very small area in Papuk Nature Park, and several localities in the town of Ilok and the surrounding area. On Mt Papuk, the species is limited to an area of the warm southern slopes of the Turjak-Mališćak-Pliš peaks, above Velika. In the year 2019, the species was documented in a new location, on Stinice. The aim of this study is to analyse morphometric measures, relative density, predatory pressure, and to determine the sustainability of this population. Data obtained were compared with the previous research into the European snake-eyed skink on Turjak, the most researched European snake-eyed skink site on Papuk so far. The population on Stinice has lower density, and is under higher predatory pressure than the population on Turjak. Also, there are differences in some morphometric measures between these two populations that should be further explored

Analiza programa specijalističke izobrazbe iz oftalmologije

The aim of the study was to perform qualitative and quantitative analysis of residency curriculum in ophthalmology. A structured anonymous questionnaire was distributed to 73 medical doctors who were at least on the second year of their residency training in ophthalmology or young ophthalmologists with maximum 4 years of experience. The questionnaire consisted of 52 questions covering every segment of education from the current Protocol for Residency Education of Health Care Professionals in Ophthalmology. Forty-two (58%) doctors answered the questionnaire. Qualitative analysis showed that most of the procedures were mastered by residents. Diagnostic and/or examination procedures were mastered better than surgical and/or interventional procedures. Quantitative analysis showed that the majority of residents failed to reach the prescribed number of surgical procedures. Thirty-three (79%) participants were not satisfied with the current residency curriculum. Although residents mastered most of the prescribed procedures, current residency curriculum is far from being perfect and needs improvements. We think that objective assessment tools for monitoring the progress and competencies of residents during their residency training need to be developed.Cilj rada bio je provesti kvalitativnu i kvantitativnu analizu programa specijalističkog usavršavanja iz oftalmologije metodom anonimne ankete. O anonimnoj anketi obaviještena su ukupno 73 doktora medicine koji su bili najmanje na drugoj godini specijalizacije iz oftalmologije, odnosno oftalmolozi s maksimalno 4 godine specijalističkog staža. Anketa se sastojala od 52 pitanja vezana uza sve dijelove izobrazbe iz aktualnog Pravilnika o specijalističkom usavršavanju zdravstvenih djelatnika iz oftalmologije. Anketu su ispunila 42 (58%) doktora. Kvalitativna analiza pokazala je kako je većina predviđenih zahvata uspješno svladana za vrijeme specijalizacije. Dijagnostički zahvati i/ili razne metode pregleda svladani su bolje nego kirurški i/ili interventni postupci. Prema kvantitativnoj analizi većina specijalizanata nije ispunila predviđeni broj kirurških zahvata. Trideset troje (78%) sudionika nije zadovoljno trenutnim programom specijalističkog usavršavanja. Dakle, premda su specijalizanti ovladali većinom predviđenih zahvata, sadašnji program specijalističkog usavršavanja daleko je od savršenog i potrebna su poboljšanja. Smatramo da je potrebno razviti kvalitetne metode za objektivnu procjenu napretka i kompetentnosti specijalizanata za vrijeme specijalizacije

Analiza programa specijalističke izobrazbe iz oftalmologije

The aim of the study was to perform qualitative and quantitative analysis of residency curriculum in ophthalmology. A structured anonymous questionnaire was distributed to 73 medical doctors who were at least on the second year of their residency training in ophthalmology or young ophthalmologists with maximum 4 years of experience. The questionnaire consisted of 52 questions covering every segment of education from the current Protocol for Residency Education of Health Care Professionals in Ophthalmology. Forty-two (58%) doctors answered the questionnaire. Qualitative analysis showed that most of the procedures were mastered by residents. Diagnostic and/or examination procedures were mastered better than surgical and/or interventional procedures. Quantitative analysis showed that the majority of residents failed to reach the prescribed number of surgical procedures. Thirty-three (79%) participants were not satisfied with the current residency curriculum. Although residents mastered most of the prescribed procedures, current residency curriculum is far from being perfect and needs improvements. We think that objective assessment tools for monitoring the progress and competencies of residents during their residency training need to be developed.Cilj rada bio je provesti kvalitativnu i kvantitativnu analizu programa specijalističkog usavršavanja iz oftalmologije metodom anonimne ankete. O anonimnoj anketi obaviještena su ukupno 73 doktora medicine koji su bili najmanje na drugoj godini specijalizacije iz oftalmologije, odnosno oftalmolozi s maksimalno 4 godine specijalističkog staža. Anketa se sastojala od 52 pitanja vezana uza sve dijelove izobrazbe iz aktualnog Pravilnika o specijalističkom usavršavanju zdravstvenih djelatnika iz oftalmologije. Anketu su ispunila 42 (58%) doktora. Kvalitativna analiza pokazala je kako je većina predviđenih zahvata uspješno svladana za vrijeme specijalizacije. Dijagnostički zahvati i/ili razne metode pregleda svladani su bolje nego kirurški i/ili interventni postupci. Prema kvantitativnoj analizi većina specijalizanata nije ispunila predviđeni broj kirurških zahvata. Trideset troje (78%) sudionika nije zadovoljno trenutnim programom specijalističkog usavršavanja. Dakle, premda su specijalizanti ovladali većinom predviđenih zahvata, sadašnji program specijalističkog usavršavanja daleko je od savršenog i potrebna su poboljšanja. Smatramo da je potrebno razviti kvalitetne metode za objektivnu procjenu napretka i kompetentnosti specijalizanata za vrijeme specijalizacije

Intralezijska injekcija triamcinolon acetonida u liječenju halaziona

The aim of the study was to evaluate the efficacy of intralesional triamcinolone acetonide injection in primary and recurrent chalazion. The study included 30 patients with primary and recurrent chalazion (37 cases) and 24 patients as a control group. Patients with primary and recurrent chalazion received intralesional injection of 0.1 to 0.2 mL triamcinolone acetonide (40 mg/mL). Control group received intralesional injection of 0.1 to 0.2 mL 0.9% NaCl. Data on the lesion size, including digital color photography, lesion regression or recurrence, and complete ophthalmic examination were recorded at the time of injection and after a week or two until resolution or surgical excision. Success was defined as at least 80% decrease in size with no recurrence. Resolution of the lesion was found in 35 cases after one or two injections, with a mean time to resolution of15.27±6.12 days. Subcutaneous injection of the steroid triamcinolone acetonide in primary and recurrent chalazion appears to be a simple and efficacious therapeutic option for chalazion.Cilj studije bio je procijeniti učinkovitost intralezijskog injektiranja triamcinolon acetonida kod primarnog i recidivirajućeg halaziona. U ispitivanje je bilo uključeno 30 bolesnika s primarnim i recidivirajućim halazionom (37 slučajeva) i 24 bolesnika kao kontrolna skupina. Bolesnici s primarnim i recidivirajućim halazionom primili su intralezijsku injekciju 0,1 do 0,2 mL triamcinolon acetonida (40 mg/mL), dok su bolesnici kontrolne skupine primili intralezijsku injekciju 0,1 do 0,2 mL 0,9%-tne NaCl. Podatci o veličini lezije, uključujući digitalnu fotografiju u boji, regresiji ili recidivu lezije te o cjelokupnom oftalmološkom pregledu bilježili su se u vrijeme injektiranja te nakon jednog ili dva tjedna do povlačenja ili kirurškog odstranjenja lezije. Uspješnost je definirana kao najmanje 80%-tno smanjenje veličine lezije bez recidiva. Povlačenje lezije utvrđeno je u 35 slučajeva nakon jedne ili dvije injekcije, srednje vrijeme do povlačenja od 15,27±6,12 dana. Potkožno injektiranje steroida triamcinolon acetonida kod primarnog i recidivirajućeg halaziona pokazalo se jednostavnom i učinkovitom terapijom za halazion