Direct Potentiometric Measurements of Cysteine by Using Iodide-Selective Electrode

Potentiometric determination of cysteine (Cys) in aqueous solution by using iodide-selective electrode with (Ag2S + Agl) membrane is described. The analytical behaviour of this electrode is discussed in terms of the potential vs. concentration curve, potential vs. pH curve, and potential-time response. The equilibrium potentials observed during serial dilution or standard addition, under constant pH and ionic strenght, are plotted against log c(Cys). The linear response with a slope 58 mV {p(Cys)}-1 has been obtained in the concentration range from 3 x 10-3 to under 10"5 M. The change in potential in the tested concentration range of Cys (also designated as RSH) indicates RSAg coating formation at the exposed membrane surface. On the basis of potentiometric experiments, the solubility product of RSAg precipitate has been determined. The calculated mean value was pffsp(RSAg) = 18.66 ± 0.08

The demographic development of Nin in the 20th century

U ovom radu analizira se demografski razvoj naselja Nin u razdoblju 1900. – 1999. godine, na što su utjecali povijesni i društveni procesi. Povijesno promatrajući, to je razdoblje vladavina Druge austrijske uprave, Kraljevine SHS/Jugoslavije, Federativne Narodne Republike Jugoslavije, Socijalističke Federativne Republike Jugoslavije i samostalne Republike Hrvatske. To razdoblje obilježila su također dva svjetska rata i oslobodilački Domovinski rat u Hrvatskoj, što je imalo utjecaj na ukupne demografske procese.The paper addresses the demographic development of Nin during the 20th century. The study was conducted for the following settlements: Nin, Grbe and Ninski Stanovi. Thereby, these demographic indicators were followed: birth rate, death rate, migration saldo and nuptiality. The demographic development of Nin has been pictured through the usual demographic indicators, together with other Croatian land settlements in the first 70 years of the 20th century. At the beginning of the analysed period, Nin underwent the second, transitional phase described in the Theory of demographic transition, with high birth rate and low death rate, which resulted in population growth. However, in the last quarter of the 20th century, demographic processes untypical of littoral land settlements took place. In the period between the censuses in 1971 and 1981, the number of inhabitants decreased significantly, while in the following period between the censuses in 1981 and 1991, it increased strongly. Finally, in the last studied period between the censuses in 1991 and 2001, it decreased again remarkably. The causes for this kind of demographic changes differed and have not been explained entirely. However, one of the major causes thereof were various census coverages taken into consideration in 1981 and 1991, to which fact demographers had been indicating earlier. This paper has confirmed two theses. The first thesis is that the number of inhabitants in the historic centre had decreased, following thereby the trends of Croatian and European tourist towns and cities and their historic centres. The second thesis is that Nin, though being a littoral tourist town, did not undergo the (beneficiary) process of littoralisation – at least not in the demographic sense, as in the last studied period there was a significant decrease in the number of inhabitants: nearly 634, or 30%

Renesansa elektroda s ugljikovom pastom; njihove modifikacije i primjene u potenciometrijskim određivanjima farmaceutika

Razvoj elektroda s ugljikovom pastom (CPE, engl. carbon paste electrode) sedamdesetih godina prošlog stoljeća privukao je velik interes znanstvene zajednice budući da je otkriveno da one nude nekoliko prednosti u odnosu na konvencionalne membranske elektrode. Početkom novog tisućljeća dodatni impuls njihovom razvoju dala je primjena ugljikovih nanomaterijala kao novog trenda u njihovu razvoju. Nakon što su uspješno razvijene CPE za potenciometrijsko određivanje više od 70 kemijskih elemenata, te su elektrode privukle dodatno zanimanje za primjenu u farmaciji i medicini. Ovim radom dat je pregled znanstvene literature u posljednjih desetak godina vezan za razvoj CPE za kvantitativno određivanje djelatnih tvari farmaceutika i njihovu primjenu u realnim uzorcima

MARINE SEDIMENTS CHARACTERISTICS IN THE SPLIT AREA

The distributions of granulometric composition, organic matter and carbonate content were determined in the sediment core at three stations and in the samples from surface sediment at eight stations in Split area (eastern Adriatic Sea). According to average values, clay and silt particles prevail in the sediment core and surface sediment. Average values of organic matter content for the three stations were 7.6 ± 0.9%, with range from 4.9 to 9.9%. In the surface sediment, average values were 6.2 ± 1.8%, with range from 3.9 to 8.9%. In the sediment core samples average values of carbonate were 45.1 ± 4.6%, with the range from 36.6 to 71.7%, while average values of carbonate in surface sediment were 52.5 ± 8.2%, with range from 41.1 to 66.5%. According to the Folk classification, the sediment type at Stations 1 and 2 is mud, and at Station 3 slightly gravelly sandy muds. In the surface sediment, at the four stations, prevailing sediment type is mud, following slightly gravelly sandy mud (at three stations), while sandy mud was determined only at one station According to the Shepard classification in sediment core prevailing sediment type is silty clay, while in surface sediment, sediment type vary from silty clay (clayey silt mixture to silt). Very poorly (2.08) to extremely poorly sorted (6.85) sediment indicated different origin of settled particles (terrigenous and biogenous). The relationship between determined parameters in the sediment was established using the regression analysis (Spearman correlation and Cluster analysis). Results of the Cluster Analysis, using all the investigated parameters (granulometric composition, organic matter and carbonate content) confirmed the granulometric composition as a leading differentiation parameter between investigated sediments

Sensitive Electrochemical Determination of Folic Acid Using ex–situ Prepared Bismuth Film Electrodes

The electrochemical behavior of folic acid (FA), at the electrochemically prepared ex situ bismuth film (BiF) on glassy carbon electrode, clearly indicates electrocatalytic nature of the prepared film toward FA reduction (at –0.55 V). Scanning electron microscopy is used for morphological characterization of the prepared BiF. Accordingly, we establishing an electrochemical procedure based on square wave cathodic stripping voltammetry, preceded by accumulation of FA on the BiF electrode (BiFE). This analytical method is optimized and its analytical performance is presented. This electrode displays a two linear response range: 0.1 to 1.0 μmol L–1 and 1.0–10.0 μmol L–1 with sensitivity of 20.10 μA μmol–1 L and 2.28 μA μmol–1 L, respectively. Developed method was validated in compliance with spectrophotometric method. Excellent recovery and standard deviation obtained with BiFE revealed great analytical potential of the proposed method which was applied for the determination of FA in pharmaceuticals formulation. This work is licensed under a Creative Commons Attribution 4.0 International License

Comparative Study of the Total Acidity Determination in Wine by Potentiometric and Volumetric Titration

Total acidity was determined in thirty-seven samples of Croatian red, white and rosé wines by potentiometric titration. In order to find the effect of the corresponding rate of the automatic titrant added, several procedures were employed. For different rates of titration, the aberrances were found from 0.1 to 0.4 g L–1 for some wines. The value of the total acid content in wine determined by the automatic potentiometric titration method was compared to that obtained by the conventional volumetric titration method. The ANOVA and cluster analysis (CA) were applied to detect possible resemblance. The results of total acidity depended on the methods used. However, a good correlation between the results by these methods was found

MULTIVARIATE ANALYSIS OF POLLUTION INDICATORS OF MUNICIPAL WASTEWATER IN SPLIT AREA

This paper presents the results of continuous monitoring of 11 pollution indicators of municipal wastewater that were discharged into the natural recipient (the sea) at three locations in the Split area during four years (2006-2009). Experimental data were analyzed by basic statistical methods for determination of mean and median values, standard deviations, minimal and maximal value of the measured parameters and their mutual correlation coefficients, normality test for all parameters and by different chemometric methods, such as cluster analysis (CA), factor analysis (FA) and principal component analysis (PCA). Multivariate statistical techniques for evaluation and interpretation of large complex data sets used in this study provide better insight into the information about water quality and make a decision concerning the design of monitoring network for effective management of water resources much easier

Monthly and Seasonal Variations of NO2, SO2 and Black-smoke Located Within the Sport District in Urban Area, City of Split, Croatia

This paper represents, for the first time, scientific data as a part of monitoring air quality in the city of Split. The city has a problem with the air pollution mostly caused by anthropogenic activities and partly by natural origin activities. This study presents results of monthly and seasonal variations of NO2, SO2 and black-smoke as well as the influence of meteorological parameters on observed concentration levels. Average seasonal values for SO2 ranged from 22.54 to 54.81 g m–3, for NO2 from 48.24 to 56.38 g m–3 and for black-smoke from 4.15 to 5.64 g m–3. The results obtained for SO2 and black-smoke were below, while for NO2 were above the limit value of pollutants in the air recommended by Croatian Government (Air Protection Act (OG 178/04); Regulation on limit values of pollutants in air (OG 133/05)). As the result of stable meteorological conditions (high temperatures and drought), the increase in SO2 concentration was significant in summer period, while the concentrations of NO2 and black-smoke were not significantly changed during year and did not depend on other parameters. (doi: 10.5562/cca1966

CHILD IN CONTEMPORARY CROATIAN SOCIETY

U Zagrebu je 12. prosinca 2009. održan simpozij »Dijete u suvremenome hrvatskom društvu«, koji su organizirali Hrvatsko pedijatrijsko društvo, Hrvatska akademija znanosti i umjetnosti, Ministarstvo zdravstva i socijalne skrbi i UNICEF za Hrvatsku. Predavači su prikazali važne podatke o teškoćama kojima su izložena djeca u Hrvatskoj. Naime, nove bolesti, koje su u suvremenom svijetu sve češće u djece, zahtijevaju od svih koji su uključeni u zdravstvenu zaštitu djece nove pristupe radu, što podrazumijeva i dodatnu edukaciju. To nisu bolesti uobičajene u svakodnevnoj liječničkoj praksi. Pristup društva, zbog raznolikosti teškoća s kojima se djeca suočavaju, može biti samo multidisciplinaran. Temeljni nacionalni interes društva je usmjeriti više pozornosti i financijska sredstva na zdravstvenu zaštitu djece, jer to osigurava opstanak i zdravu budućnost društva. Taj pristup zahtijeva nacionalni konsenzus i jasnu političku odluku svih odgovornih službi.The symposium on the topic »Child in contemporary Croatian society«, organized by Croatian Pediatric Society, Croatian Academy of Sciences and Arts, Ministry of health and social welfare and UNICEF Croatia Office, was held in Zagreb on December 12, 2009. The lecturers have shown important information on difficulties the children in Croatia are exposed to. Namely, diseases of the so called »new morbidity«, which are becoming more and more frequent in the contemporary world, demand a new approach of work from all who participate in healthcare for children, including additional education. These diseases are not part of a practitioner’s routine activity. Due to variety of problems children are exposed to, the approach can be only multidisciplinary. Basic national interest of every country (basic interest of every human society) should be to direct more attention and financial resources to the healthcare of children, which would ensure the existence and healthy future of the society. This approach requires a national consensus and clear political decision of all responsible official services

CHILD IN CONTEMPORARY CROATIAN SOCIETY

U Zagrebu je 12. prosinca 2009. održan simpozij »Dijete u suvremenome hrvatskom društvu«, koji su organizirali Hrvatsko pedijatrijsko društvo, Hrvatska akademija znanosti i umjetnosti, Ministarstvo zdravstva i socijalne skrbi i UNICEF za Hrvatsku. Predavači su prikazali važne podatke o teškoćama kojima su izložena djeca u Hrvatskoj. Naime, nove bolesti, koje su u suvremenom svijetu sve češće u djece, zahtijevaju od svih koji su uključeni u zdravstvenu zaštitu djece nove pristupe radu, što podrazumijeva i dodatnu edukaciju. To nisu bolesti uobičajene u svakodnevnoj liječničkoj praksi. Pristup društva, zbog raznolikosti teškoća s kojima se djeca suočavaju, može biti samo multidisciplinaran. Temeljni nacionalni interes društva je usmjeriti više pozornosti i financijska sredstva na zdravstvenu zaštitu djece, jer to osigurava opstanak i zdravu budućnost društva. Taj pristup zahtijeva nacionalni konsenzus i jasnu političku odluku svih odgovornih službi.The symposium on the topic »Child in contemporary Croatian society«, organized by Croatian Pediatric Society, Croatian Academy of Sciences and Arts, Ministry of health and social welfare and UNICEF Croatia Office, was held in Zagreb on December 12, 2009. The lecturers have shown important information on difficulties the children in Croatia are exposed to. Namely, diseases of the so called »new morbidity«, which are becoming more and more frequent in the contemporary world, demand a new approach of work from all who participate in healthcare for children, including additional education. These diseases are not part of a practitioner’s routine activity. Due to variety of problems children are exposed to, the approach can be only multidisciplinary. Basic national interest of every country (basic interest of every human society) should be to direct more attention and financial resources to the healthcare of children, which would ensure the existence and healthy future of the society. This approach requires a national consensus and clear political decision of all responsible official services