The reduction of nitroaromatic compaunds on the platinum electrode

The reduction of 2,4,6-trinitrotoluene (TNT),as an example of nitroaromatic compounds with three nitro groups, was investigated by cyclic voltammetry on a platinum electrode in aqueous sodium chloride solutions with acetonitrile. The obtained cyclic voltammograms showed three well-pronounced reduction peaks in the potential range of –0.43 to –0.8 V (vs. Ag/AgCl reference electrode). The potentials of the peaks were dependant on the potential scan rate as well as on the TNT concentration, indicating the irreversibility of the reduction process. A calibration curve as a linear dependence of the first peak current on the TNT concentration was obtained in the range 4.4 – 638.4 μM L–1.The platinum electrode exhibited an electrochemically stabile behavior for the TNT reduction process. Hence, a Pt electrode could be a suitable material for TNT sensing.Belgrade, Serbia, June 6-10, 201

Application of new polymer-clay nanocomposite materials in purification of water containing phenol derivatives.

Predmet rada ove doktorske disertacije bio je sinteza i karakterizacija aminofunkcionalizovanog makroporoznog nanokompozita polimera i gline, koji je u laboratorijskim uslovima ispitan kao sorbens za uklanjanje derivata fenola iz vodenih rastvora. Nanokompozit poli(glicidilmetakrilata-ko-etilenglikoldimetakrilata) i kiselomodifikovanog bentonita dobijen je postupkom suspenzione kopolimerizacije preko slobodnih radikala. Zatim je nanokompozit funkcionalizovan reakcijom sa dietilentriaminom (deta). Funkcionalizacija je od ključnog značaja za sorpcionu sposobnost i selektivnost kompozita. Ispitivani kompozit je upoređen sa kopolimerom poli(glicidilmetakrilata-koetilenglikoldimetakrilatom). Urađena je karakterizacija nefunkcionalizovanih i funkcionalizovanih uzoraka (kopolimera i kompozita) hemijskom analizom, infracrvenom spektroskopijom, skenirajućom elektronskom mikroskopijom (SEM), transmisionom elektronskom mikroskopijom (TEM) i određivanjem teksturalnih svojstava. TEM analizom potvrđeno je da sintetisani kompozit ima nanokompozitnu strukturu i da se najbolje može opisati kao disperzija interkalisanih i razlistanih agregata u polimernoj matrici. Pored prisustva funkcionalnih grupa i teksturalna svojstva uzoraka su značajna za sorpcionu efikasnost. Uočeno je da se kod nanokompozita, za razliku od kopolimera, koji je dominantno makroporozan (sa prečnikom pora > 50 nm), javlja i značajan udeo mezopora (sa prečnikom pora od 2 do 50 nm). Prisustvo mezopora uslovljava da nanokompozit ima veću specifičnu površinu i ukupnu zapreminu pora. Određivanjem sadržaja amino grupa funkcionalizovanih uzoraka dobijena je nešto niža vrednost za kompozit u odnosu na kopolimer što može biti posledica manje dostupnosti epoksidnih grupa kod nanokompozita...Amino-functionalized macroporous polymer-clay nanocomposite was synthesized and fully characterized. This material was investigated under laboratory conditions as a sorbent for removal of phenol derivatives from water solutions. Nanocomposite of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and acid modified bentonite was prepared by radical suspension copolymerization and functionalized with diethylenetriamine (deta). The purpose of functionalization was to enable sorption and selectivity of the composite. Investigated composite was compared with copolymer poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate). Nonfunctionalized and functionalized samples (copolymer and composite) were characterized by chemical analysis, Infrared Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and their textural properties were determined. TEM analysis confirmed that the synthesized composite had nanocomposite structure which can be best described as a dispersion of intercalated and exfoliated aggregates in polymeric matrix. Besides functional groups, textural properties of samples are also important for sorption efficiency. It was observed that besides macropores (pore diameter: > 50 nm) which are characteristics of copolymers, nanocomposite contained a significant amount of mesopores (pore diameter: 2-50 nm). The presence of mesopores led to higher specific surface area and total pore volume of nanocomposite. The content of amino groups in the functionalized composite (CP-SA-deta) was slightly lower than in the functionalized copolymer (CP-deta). This could be the consequence of the lower accessibility of epoxy groups in CP-SA-deta..

The galvanostatic reduction on modified platinum electrode and determination of trinitrotoluene in neutral solution

The study of the electrochemical reduction on acetonitrile modified platinum electrode and determination of trinitrotoluene (TNT) in neutral solution by simple galvanostatic technique is presented here. The obtained potential-time responses on the applied constant cathodic current pulses showed two potential transitions before achieving the steady-states, referring to the multi-step reduction process of nitro groups in TNT molecule. The calibration curves of the dependence of the square root of the first transition time (τ 0.5) on the TNT concentration were linear in the ranges 4.4 – 303.8 μM and 0.09 – 4.40 μM for applied constant current of 0.1 mA. The detection limit was 0.09 μM. The method was tested in the river water. The results indicated the sensitivity of the galvanostatic method for TNT determination in the environmental samples. From the first transition on the E-t curves the characteristics important for the understanding the mechanism of the reduction process were obtained. It was found that four electrons are involved in the reduction process of the first nitro group, indicating that the reduction product in a neutral electrolyte is hydroxylamine.\ud Keywords

Masivna tromboza abdominalne aorte s distalnom embolijom kao jedina klinička manifestacija COVID-19 infekcije

COVID-19 infection usually presents with respiratory symptoms and fever however several unusual initial presentations of this infection were reported in literature. We report a case of arterial thrombosis as a presenting features of this disease without any other COVID-19-related symptoms. This might lead to delayed COVID-19 diagnosis and isolation of suspected patient causing epidemiologic consequences and increased risk of transmission of the virus inside the hospital in time of pandemic unless timely recognized.Infekcija COVID-19 se obično manifestira respiratornim simptomima i vrućicom, no u literaturi je opisano nekoliko neuobi-čajenih početnih simptoma bolesti. Prikazujemo slučaj bolesnice s trombozom arterije kao jedinom kliničkom prezentacijom ove bolesti, bez drugih uobičajenih simptoma vezanih uz COVID-19. Ukoliko se pravovremeno ne prepozna, to može rezultirati odgo-đenim dijagnosticiranjem i izolacijom suspektnog bolesnika te uzrokovati epidemiološke posljedice i povećani rizik prijenosa virusa unutar bolnice u doba pandemije

Neuroimaging Techniques in Modern Forensic Psychiatry

Applied neuroscientific knowledge such as brain neuroimaging has widespread application in the medical diagnostic and treatment areas. Neuroscientific progress such as cognitive neuroscience has strong implications in specific medical fields such as forensic psychiatry. Significant progress in forensic psychiatry has affected the practice of law, in which an understanding of the complex relationship among mind, brain, and behavior is becoming necessary. Forensic psychiatry is concerned with the relationship between psychiatric abnormalities and legal violations and crimes. Due to the lack of available biological criteria, assessment, evaluation and therapy in forensic psychiatry have so far been restricted to psychosocial and mental criteria of offender personality. Recent advances in nuclear radiology such as brain imaging techniques (fMRI, DT-MRI, PET, SPECT) allow a closer approach to the neural correlates of personality, moral judgments and decision-making. Introduction of neurobiological criteria (based on advanced neuroimaging techniques) in the field of forensic psychiatry and establishing the rules to what extent such biological criteria will be more reliable choice in evaluating mentally ill offenders would be of fundamental value in the modern forensic psychiatry. Psychosocial and subjective criteria in forensic evaluation will be more accomplished by biopsychosocial and objective criteria. Advances in the neuroimaging techniques bring specificity to the problems underlying the application of neuroscience to criminal law

Sunlight and Incidence of Pterygium on Croatian Island Rab – Epidemiological Study

The aim of this epidemiologic study, on small island Rab, in North Adriatic Sea, is to estimate correlation between climatic factors, specially chronic exposure to strong visible and UV light, and appearance of pterygium and exfoliation syndrome. In the first group of population which live in a village and who are agriculturists and fishermen (480 persons) appearance of pterygium is in 23% (16% in males and 7% in females), but 0.0% in urban people (61 people). The appearance of exfoliation syndrome was in the first group of agriculturists and fishermen population in 21%, of which 19% of males and 2% of females, and in urban people 0.0%. The higher intraocular pressure in exfoliation syndrome was 92%. All population in this examination were in the highest age (mean age is 65–80 years). Chronic exposure to sunlight caused the high percentage appearance of pterygium and exfoliation syndrome

ALLERGOLOGIC EMERGENCIES IN DERMATOLOGY DIAGNOSTIC AND THERAPEUTIC PROCEDURES

Hitna stanja u alergologiji i kliničkoj imunologiji sve su češći medicinski javno zdravstveni problem u nas i u svijetu. Česte su alergijske reakcije od blagih simptoma kao što je svrbež do generaliziranih kožnih, gastrointestinalnih, respiratornih simptoma do anafilaksije i zatajenja kardiovaskularnog sustava. Pri tom su moguće reakcije na različite udisajne tvari, hranu i aditive u hrani, strane tvari (krv, lateks i drugo) te brojne poznate antigene i lijekove koji putem imunskih kompleksa i reakcija posredovanih oslobađanjem komplementa ili direktnim oslobađanjem histamina (opijati ili dekstran) te zbog modulatora metabolizma arahidonske kiseline (npr. NSAID) i drugo. NSAID često uzrokuju astmu, urtikarijski osip, angioedem i još 35 različitih dermatoloških reakcija, posebice kod primjene lijekova koji zahtijevaju hitan terapijski postupak. Reakcije od uboda insekata pojavljuju se ne samo s bolnim infiltratima, nego i diseminiranim osipima i edemom. Suvremene dijagnostičke metode, a posebice hitni terapijski postupci, sukladno internacionalnom k oncenzusu (npr. European Allergy White Paper) ukazuju na potrebu ujednačavanja stavova u kliničkoj praksi. Velik broj bolesnika se liječi zbog alergijskih kožnih bolesti neadekvatno, upućuje na testiranja često u fazi aktivne bolesti i kad su pod terapijom, a liječe se kortikosteroidima i antihistaminicima duže no što je potrebno. Suvremeno liječenje hitnih stanja zahtijeva izobraženu osobu, no svaki liječnik treba odgovarati za liječenje akutnih simptoma u svojoj ordinaciji i poznavati postupak za hitno liječenje točno određenim lijekovima. Anafilaktične reakcije su rijetke, ali svaki liječnik treba biti pripravan na najteže situacije i poznavati liječenje u hitnom postupku. U radu navodimo najčešće bolesti za koje je potreban hitan postupak liječenja, a u fazi regresije bolesti dijagnostički postupci.Emergencies in allergology and clinical immunology are quite common and pose a public health problem in Croatia and worldwide. Allergic reactions ranging from mild symptoms such as pruritus to generalized skin eruptions, gastrointestinal and respiratory symptoms to anaphylaxis with cardiovascular emergencies are very common. Reaction develops to inhalant substances, food and food ingredients, various foreign substances (blood, latex, etc.) and many other well known antigens and drugs which are frequent causes of anaphylactic reactions, asthma, generalized urticaria, angioedema. There are 35 different skin reactions induced by drugs through immune complexes, complement mediated reactions and direct histamine liberation (by opiates or dextran) and modulators of arachidonic acid metabolism (such as NSAID). Along with painful infiltrates, insect venom allergy manifests with disseminated exanthema and angioedema. Current diagnostic methods, especially therapeutic procedures for emergencies in concordance with the international consensus of the European Allergy White Paper, require the same procedure in clinical practice. Many patients with different allergic skin diseases are treated inappropriately, some are tested in active phase of the disease, during anti-allergic therapy, and some are administered corticosteroids and antihistamines longer than necessary. Sometimes, the treatment of emergencies requires a person experienced in intensive care medicine. However, any physician might be responsible for the treatment of acute symptoms in his office, and thus has to know the modalities and relevant drugs and treatment essentials. Anaphylactic reactions are rare, but every physician should be prepared for the worst. Due knowledge of the correct management should be a must for all of us. The most common emergencies require emergency treatment and diagnostic procedures upon disease regression

Personal Identification by Eyes

Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems using iris recognition are among the most secure biometric systems