Kinetic Determination of Arsenic(III) as Inhibitor of Victoria Blue 4R Oxidation in Strong Acid Solution

A new selective, sensitive and simple kinetic method was developed for the determination of As3+ traces in solution on the basis of their inhibiting effect on Victoria blue 4R (VB) oxidation by KBrO3 in the presence of HCl. The reaction was followed spectrophotometrically at 596.3 nm. The detection limit was 50.00 ng cm–3. The relative error vas 4.2 % to 1.5 % for As3+ in the concentration range from 80.00 to 350.00 ng cm–3. Also, appropriate kinetic equations were formulated and the influence of different ions upon the reaction rate was studied. The developed procedure was successfully applied to the determination of As3+ in various model and real samples

Macroelements versus toxic elements in selected wild edible mushrooms of the Russulacea family from Serbia

Three edible mushrooms of the Russulacea family (Lactarius deliciosus, Lactarius sanguifluus and Lactarius semisanguifluus), most frequently consumed in Serbia, were analyzed using the ICP-OES technique to evaluate the content of K, P, Ca, Mg, Na, Al, As, Cd and Pb, both in cap and stipe. Corresponding soils were analyzed, too. Based on the obtained values for the elemental composition of the mushrooms and the soil, bioaccumulation and translocation factors were calculated. All the examined mushrooms species were recognized as bioexclusors of analyzed toxic elements, but bioaccumulators of K, P and Ca. The studied mushrooms are good sources of macroelements. One portion of 300 g of fresh mushrooms had a significant contribution of K and P, exceeding 15 % of the recommended daily intake for the elements. On the contrary, mushrooms had a low potential to bioaccumulate toxic elements, and presented results indicated the regular consumption of wild edible mushrooms is safe for human health. Correlation analysis was applied to determine phosphorus’s influence on the elements’ content in the mushrooms and corresponding soils, demonstrating the most remarkable mushrooms' tendency to accumulate phosphorus.Циљ овог рада било је одређивање садржаја K, P, Ca, Mg, Na, Al, As, Cd и Pb у три јестиве, самоникле печурке (Lactarius deliciosus, Lactarius sanguifluus и Lactarius semisanguifluus) које припадају породици Russulacea. Такође, одређен је и садржај поменутих елемената у земљишту на коме су расле анализиране печурке. На основу добијених резултата, за сваки елемент је израчунат биоакумулациони и транслокациони фактор. Будући да је утврђено да печурке акумулирају одговарајуће макроелементе, резултати су приказани и као унос (%) одговарајућих елемената на основу препоручене дневне дозе, прерачунато на порцију од 300 g свежих печурака. За токсичне елементе израчунат је садржај уноса елемената на основу прихватљивог недељног уноса. Корелациона ана- лиза је коришћена како би се утврдио утицај фосфора на садржај елемената у печур- кама и одговарајућим земљиштима, обзиром да је фосфор показао најзначајнију тен- денцију акумулације

Ramalina capitata (Ach.) Nyl. acetone extract

In the present investigation, effects of Ramalina capitata acetone extract on micronucleus distribution on human lymphocytes, on cholinesterase activity and antioxidant activity (by the CUPRAC method) were examined, for the first time as well as its HPLC profile. Additionally, total phenolic compounds (TPC), antioxidant properties (estimated via DPPH, ABTS and TRP assays) and antibacterial activity were determined. The predominant phenolic compounds in this extract were evernic, everninic and obtusatic acids. Acetone extract of R. capitata at concentration of 2 μg mL-1 decreased a frequency of micronuclei (MN) for 14.8 %. The extract reduces the concentration of DPPH and ABTS radicals for 21.2 and 36.1 % (respectively). Values for total reducing power (TRP) and cupric reducing capacity (CUPRAC) were 0.4624 ± 0.1064 μg ascorbic acid equivalents (AAE) per mg of dry extract, and 6.1176 ± 0.2964 μg Trolox equivalents (TE) per mg of dry extract, respectively. The total phenol content was 670.6376 ± 66.554 μg galic acid equivalents (GAE) per mg of dry extract. Tested extract at concentration of 2 mg mL-1 exhibited inhibition effect (5.2 %) on pooled human serum cholinesterase. The antimicrobial assay showed that acetone extract had inhibition effect towards Gram-positive strains. The results of manifested antioxidant activity, reducing the number of micronuclei in human lymphocytes, and antibacterial activity recommends R. capitata extract for further in vivo studies

Enzimska kinetička metoda za određivanje propranolol-hidrohlorida u farmaceutskim preparatima zasnovana na njegovom inhibitorskom delovanju na holinesterazu

Propranolol, a widely used beta-blocker, inhibits the hydrolysis reaction of enzyme cholinesterase. Measurements of the difference in rate of hydrolysis rate between uninhibited and inhibited reactions allow the development of a kinetic method for its determination. Both systems, enzyme-substrate-chromogen and enzyme-substrate-chromogen-inhibitor, were characterized through biochemical kinetic parameters (K-M, 0.326-0.330 mmol/L; V-max, 40.0-43.0 mu mol/Lmin). The inhibition type was recognized as competitive and the inhibition constant, Ki, was determined to be 22.60 mu mol/L. The detection and quantification limits were calculated as 0.004 and 0.0136 mu mol/L, respectively. Accuracy and precision of proposed methods were tested. The proposed method showed good sensitivity, selectivity, simplicity and rapidity, thus it is convenient for clinical applications.Za propranolol, često propisivani neselektivni beta blokator, utvrđeno je da inhibira reakciju enzimske hidrolize butiriltioholin-jodida, koja je katalizovana serumskom holinesterazom. Merenjem razlike u brzini osnovne i inhibitorske reakcije hidrolize u prisustvu propranolola kao inhibitora, moguće je razviti kinetičku metodu za određivanje propranolola. Oba sistema, enzim-supstrat-hromogen kao i enzim-supstrat-hromogen-inhibitor, okarakterisani su biohemijskim kinetičkim parametrima (KM, 0,326-0,330 mmol/L; Vmax, 40-42,99 μmol/L min), inhibicija je definisana kao kompetitivna i određena je konstanta inhibicije 22,60 μmol/L. Da bi se u potpunosti iskoristile sve mogućnosti predložene metode u pogledu osetljivosti, tačnosti, preciznosti i selektivnosti, optimizovani su reakcioni uslovi. Konstruisana je kalibraciona prava, izračunata odgovarajuća jednačina i određeni granica detekcije i kvantifikacije i to 0,004 i 0,0136 μmol/L, redom. Tačnost i preciznost predložene metode su ispitane za tri koncentracije propranolola u oblasti kalibracione prave (0,082-21,120 μmol/L) u pet ponavljanja. Takođe, ispitan je uticaj većeg broja supstanci koje se mogu naći u uzorku na brzinu reakcije. Optimizovana metoda je primenjena za određivanje propranolola u farmaceutskim preparatima. Tačnost predložene metode je ispitana primenom metode standardnog dodatka. Predložena metoda ima dobru osetljivost, selektivnost, jednostavna je i brza, i nadasve lako dostupna, i na taj način primenljiva u velikom broju laboratorija

TWO-DIMENSIONAL FLUID MODELING OF DC GLOW DISCHARGE IN ARGON AT LOW PRESSURE

The modeling of DC glow discharge in argon at the pressure and inter-electrode distance was performed for different voltages and glow currents. For the first time, argon glow discharge is modeled using a two dimensional (2D) fluid model with non-local ionization. A detailed numerical procedure for 2D fluid modeling is given. The 2D profiles of particles number densities and electric potential obtained from the fluid model with non-local ionization and the simple fluid model are presented and compared. DVODIMENZIONI FLUIDNI MODEL JEDNOSMERNOG TINJAVOG PRAŽNJENJA U ARGONU NA NISKOM PRITISKUU radu je izvršeno modelovanje jednosmernog tinjavog pražnjenja u argonu na pritisku i medjuelektrodnom rastojanjupri različitim vrednostima primenjenih napona i radnih struja tinjavog pražnjenja. Po prvi put je modelovano tinjavo pražnjenje u argonu dvodimenzionim fluidnim modelom sa nelokalnom jonizacijom. U radu je data detaljna procedura za 2D fluidni model. Osim toga, izračunate su i  uporedjene 2D raspodele koncentracija čestica i električnog potencijala dobijenih pomoću fluidnog modela sa nelokalnom jonizacijom i  jednostavnog  fluidnog modela. HIGHLIGHTSThe modeling of DC glow discharge in argon was performed for different voltages and glow currents;Glow discharge was modeled using the two-dimensional (2D) simple fluid model and the fluid model with non-local ionization;A detailed numerical procedure for 2D fluid modeling is given;2D profiles of the particle number densities and the electric potential obtained from the fluid model with non-local ionization and the simple fluid model are presented and compared

TWO-DIMENSIONAL FLUID MODELING OF DC GLOW DISCHARGE IN ARGON AT LOW PRESSURE

The modeling of DC glow discharge in argon at the pressure and inter-electrode distance was performed for different voltages and glow currents. For the first time, argon glow discharge is modeled using a two dimensional (2D) fluid model with non-local ionization. A detailed numerical procedure for 2D fluid modeling is given. The 2D profiles of particles number densities and electric potential obtained from the fluid model with non-local ionization and the simple fluid model are presented and compared. DVODIMENZIONI FLUIDNI MODEL JEDNOSMERNOG TINJAVOG PRAŽNJENJA U ARGONU NA NISKOM PRITISKUU radu je izvršeno modelovanje jednosmernog tinjavog pražnjenja u argonu na pritisku i medjuelektrodnom rastojanjupri različitim vrednostima primenjenih napona i radnih struja tinjavog pražnjenja. Po prvi put je modelovano tinjavo pražnjenje u argonu dvodimenzionim fluidnim modelom sa nelokalnom jonizacijom. U radu je data detaljna procedura za 2D fluidni model. Osim toga, izračunate su i  uporedjene 2D raspodele koncentracija čestica i električnog potencijala dobijenih pomoću fluidnog modela sa nelokalnom jonizacijom i  jednostavnog  fluidnog modela. HIGHLIGHTSThe modeling of DC glow discharge in argon was performed for different voltages and glow currents;Glow discharge was modeled using the two-dimensional (2D) simple fluid model and the fluid model with non-local ionization;A detailed numerical procedure for 2D fluid modeling is given;2D profiles of the particle number densities and the electric potential obtained from the fluid model with non-local ionization and the simple fluid model are presented and compared

A regional survey of current practices on destination marketing organizations' Facebook pages: The case of EU and U.S.

Constantly changing nature of social network sites creates the need for continuous process of online benchmarking for identifying practices used by other parties. Facebook as the most used SNS still plays an increasingly important role as a marketing channel for destination marketing organizations (DMO). This paper explores basic characteristics of the official DMO Facebook Pages in order to quantify and present those characteristics in a regional context on the case of two travel markets (EU countries and U.S. states). The results show inconsistent practices in the EU and the USA. When comparing those two markets most similarities in practices are present in general usage of Facebook Pages, while indicative differences are recorded in terms of Page popularity, some posts' characteristics and most evidently in users' engagement. Understanding the Facebook usage practice under the regional spotlight can help DMOs and other service providers to evaluate their activities and if necessary to harmonize it to regional usage practice

Ethnomedicinal application of species from genus Thymus in the Pirot County (Southeastern Serbia)

The species from genus Thymus are polymorphous plants from the family Lamiaceae, spread in Serbia in many species, subspecies, varieties, and forms. The aerial parts of species from genus Thymus have a long tradition of being used worldwide. The subject of this study was the research of ethnomedicinal application of thyme in Pirot County (Southeastern Serbia). Ethnomedicinal surveys were conducted among the population in four municipalities: Pirot, Babušnica, Bela Palanka, and Dimitrovgrad. It was noticed that 56.9 % of interviewed persons use the species of genus Thymus in the Pirot County. They are usually used in the county’s folk medicine in the form of herbal tea against colds to relieve dry and spastic cough, especially in bronchitis and asthma, and for sedation

Total content of organic acids in plants from fire affected forest

In 2007 catastrophic fire on Vidlič Mountain had been occurred. It had been burned down nearly 1000 hectares of forest. That year vegetation was totally destroyed. Ecosystems affected by fire are those with great changes in variety of ecological parameters and they can recover by natural succession. Post fire areas are being occupied by pioneer plants which start one natural cycle. Total organic acids content in plants from fire affected forest was studied and the same plant species from forest which had not been affected by fire were taken as a control. Total organic acids content for all plants from forest affected by fire was higher than for plants from fire non affected forest except one plant (Aegopodium podagraria)

Traditional knowledge on the medicinal use of plants from genus Gentiana in the Pirot County (Serbia)

The paper provides an insight into the traditional use of medicinal plant species from the genus Gentiana in the Pirot County in Southeastern Serbia. The ethnopharmacological study was conducted in the form of interviews among the population in four municipalities: Pirot, Babušnica, Bela Palanka, and Dimitrovgrad. Among the population of Pirot County, it was noticed the use of two species from the genus Gentiana: G. cruciata and G. lutea. It was recorded that cross gentian (G. cruciata) has great popularity and versatile aspects on traditional usage, that was mentioned by 53 respondents, and that includes the treatment of cancer diseases, improving the immune system, diabetes, blood purification, for appetite, gastric and duodenal ulcer, for high blood pressure, inflammation, lung diseases. cold, cough, disease prevention, diseases of internal organs, high cholesterol, and leaking breast. The usage of the root of yellow gentian (G. lutea) was mentioned by 30 respondents, and that includes improving the immune system, appetite, for the stomach, blood purification, circulation, as an aphrodisiac, against cancer diseases, diabetes, and gastric and duodenal ulcer. It is important to note that yellow gentian, recorded in the study area, is the first species on the list of illegally collected species in Serbia