Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

Materials with disordered structures have a crucial role in the rapid development of new technologies. Improvement of these materials for particular application, as well as preparation of novel composites is based on a thorough understanding of the basic mechanisms of charge carrier transport. Among various classes of structurally disordered materials, a family of iron phosphate glasses attracts special attention due to their unique combination of structural, electrical and mechanical properties. Generally, iron phosphate glasses are electronically conducting glasses with polaronic conduction mechanism where conduction takes place by electrons hopping from Fe2+ to Fe3+. Consequently, polaron transport directly depends on Fe2+/Fetot ratio and overall Fe2O3 content. However, by altering composition (addition of Cr2O3, MoO3, PbO, Na2O) and preparation conditions, the electrical conductivity of iron phosphate based glasses may vary over many orders of magnitude. This paper gives an overview of our recent studies of electronic and ionic transport in iron phosphate based glasses. (doi: 10.5562/cca1989

Aerobni anoksigeni fototrofi Jadranskog mora

Aerobic anoxygenic phototrophs are a newly discovered member of the bacterial community in the Adriatic Sea. During the last seven years, when we started to study these organisms, we have collected a considerable number of samples from different environments, from the coast, the estuary, and the open sea. Here we have compiled data from 34 georeferenced study sites from four studies that summarize all that is known about aerobic anoxygenic phototrophs and examine the spatial and vertical distribution and environmental factors affecting this community in the Adriatic Sea. We found horizontal and vertical influences on AAP distribution, mainly salinity, nitrates, chlorophyll a, ammonium, temperature, and soluble reactive phosphorus. Much is known about their ecology in the Adriatic, and with a new survey underway, we will expand our knowledge of their community composition and their role in carbon flux to higher trophic levels.Aerobni anoksigeni fototrofi relativno su novi član bakterijske zajednice u Jadranskom moru. U posljednjih sedam godina, od kada smo započeli proučavati ove organizme, prikupili smo znatan broj uzoraka iz različitih okoliša, obalnog, estuarnog i područja otvorenog mora. U ovom radu objedinili smo podatke s 34 georeferencirane lokacije istraživanja iz četiri studije koje sažimaju sva saznanja o aerobnim anoksigenim fototrofima te istražili prostornu i vertikalnu raspodjelu, kao i okolišne čimbenike koji utječu na ovu zajednicu u Jadranskom moru. Utvrdili smo čimbenike koji utječu na horizontalnu i vertikalnu raspodjelu AAP, uglavnom salinitet, nitrate, klorofil a, amonijeve ione, temperaturu te topljivi reaktivni fosfor. Iako se dosta zna o njihovoj ekologiji u Jadranu, aktualnim istraživanjem proširit ćemo naše znanje o sastavu ove zajednice i njihovoj ulozi u protoku ugljika prema višim trofičkim razinama

Pokušaj suicida u bolnički liječenih bolesnika s epilepsijom

Persons suffering from epilepsy are in the group of patients at an increased suicide risk. The basis of every suicidal behavior, including patients suffering from epilepsy, is depression, and to explore the causes of suicidal behavior in epileptics it is necessary to find the causes responsible for the development of depression. Depression is caused by numerous factors divided into psychosocial factors, factors of the illness, and antiepileptic medication factors. The aim of the study was to identify the causes of suicidal behavior in epileptics treated in our hospital. The study included patients suffering from epilepsy treated at our Department from January 1 to December 31, 2009. Based on medical history, patients having attempted suicide were allocated to the experimental group and those without a history of suicidal attempt in the control group. Characteristics of the groups in relation to age and sex were defined first, followed by defining variables used in both groups, i.e. psychosocial factors (marital status, employment status, family environment, psychiatric comorbidity) and disease factors (etiology, type of seizures, duration of the disease, attitude towards treatment, attitude towards illness). Statistical significance was recorded in two psychosocial variables, i.e. family environment, which was significantly better in control group, and psychiatric comorbidity, which was more frequently present in patients having attempted suicide. Study results showed even 14.6% of epilepsy patients to have attempted suicide. Poor family atmosphere and psychiatric comorbidity had a significant role in suicidal behavior. In our study, the variables associated with the disease had no effect on suicidal behavior in epilepsy patients.Oboljeli od epilepsije ubrajaju se u skupinu s povećanim rizikom samoubojstva. Depresija leži u osnovi svakog suicidnog ponašanja, pa tako i kod oboljelih od epilepsije, te je u traženju uzroka suicidnog ponašanja ovih bolesnika nužno iznaći uzroke odgovorne za razvoj depresije. Uzroci depresije oboljelih su mnogobrojni i mogu se podijeliti u pretežito psihosocijalne, čimbenike vezane uza samu bolest i čimbenike medikacije. Cilj istraživanja bio je utvrditi uzroke suicidnog ponašanja osoba oboljelih od epilepsije liječenih u našoj ustanovi. Ispitivanjem su obuhvaćeni oboljeli od epilepsije liječeni na našem Odjelu od 1. siječnja do 31. prosinca 2009. godine. Uvidom u povijesti bolesti izdvojeni su bolesnici s pokušajem suicida u anamnezi koji su činili ipitivanu skupinu, a bolesnici koji nisu pokušali suicid kontrolnu skupinu. Najprije su opisane značajke skupina u odnosu na dob i spol, a zatim definirane varijable primijenjene na obje skupine: psihosocijalne (bračno stanje, radni status, obiteljsko ozračje, psihičke promjene prije početka bolesti, tj. psihijatrijski komorbiditet) i čimbenici bolesti (etiologija bolesti, vrsta napadaja, trajanje bolesti, odnos prema liječenju, odnos prema bolesti). Rezultati su pokazali statističku značajnost u dvjema psihosocijalnim varijablama: u obiteljskom ozračju koje je bilo značajno bolje u kontrolnoj skupini i u varijabli psihijatrijskog komorbiditeta. Ova varijabla je bila češća u oboljelih od epilepsije koji su pokušali suicid. Ispitivanje je pokazalo da je čak 14,6% oboljelih od epilepsije pokušalo suicid. Loše obiteljsko ozračje i psihijatrijski komorbiditet imali su znatnog udjela u suicidnom ponašanju. U provedenom ispitivanju varijable vezane uz bolest nisu imale utjecaja na suicidno ponašanje oboljelih od epilepsije

Povezanost bolesti covid-19 i poremećaja glasa

Utjecaj COVID-19 na fonatorni sustav još uvijek nije moguće metodološki konačno sumirati zbog premalog broja znanstvenih i/ili stručnih radova koji ih obrađuju.Cilj ovoga rada je dati preliminaran pregled za sada dostupnih spoznaja o fonijatrijskim posljedicama COVID-19 temeljem pregleda baza podataka. Infekcija SARS-Cov-2 virusom u visokom je omjeru praćena tegobama vezanim uz upalne procese larinksa, te simptomima kao što su disfonija, osjećaj suhoće u grkljanu, zamor glasa ili afonija. Stopa prevalencije disfonije uzrokovane SARS-Cov-2 infekcijom kreće se čak do 79%, a kao glavni uzroci izdvajaju se intubacija, postviralne paralize i pareze glasnica, te postviralna laringalna senzorna neuropatija. Čini se da COVID-19, zbog utjecaja na larinks i pluća, također posredno utječe na akustičke karakteristike glasa, pa se kod bolesnika primjećuju smanjenje maksimalnog vremena fonacije, povećana šumnost u glasu, povećan jitter i shimmer, te povećan broj prekida glasa tijekom fonacije. S obzirom na to da je disfonija kod mnogih bolesnika prisutna i nakon otpusta s bolničkoga liječenja, važno je poznavati i multidimenzionalno procijeniti moguće postojanje poremećaja glasa kod bolesnika koji imaju ili su preboljeli COVID-19. Osim toga, za odgovarajuće liječenje, kao i funkcionalni i socioemocionalni oporavak bolesnika s disfonijom, potrebna je sveobuhvatna multidisciplinarna dijagnostika koja se ponajprije odnosi na uporabu vizualizacijskih dijagnostičkih metoda, ali ju je potrebno dopuniti objektivnom i subjektivnom analizom glasa, te samoprocjenom utjecaja kvalitete glasa na svakodnevni život. Imajući u vidu ozbiljnost posljedica poremećaja glasa na kvalitetu života, u liječenju i rehabilitaciji perzistirajuće disfonije neophodna je uska suradnja otorinolaringologa, odnosno fonijatra, te logopeda

Utjecaj ekoloških čimbenika na raspodjelu dva ekotipa roda Synechococcus u obalnom moru Jadrana

Distribution and abundance of two Synechococcus ecotypes, phycocyanin-rich cells (PC-SYN) and phycoerythrin-rich cells (PE-SYN) were studied in the surface layer of the central Adriatic Sea during the 2015-2016 period. The studied area included several estuarine areas and coastal to open sea trophic gradients, covering a wide range of seawater temperatures ((11.82 - 20.75 ^oC)), salinity (4.47 - 38.84) and nutrient concentration. The abundance of PC-SYN ranged from ( 0 to 79.79 x 10^ 3 cell mL^-1) and that of PE-SYN from (5.01 x 10^3 to 76.74 x 10^3 cell mL^-1). Both ecotypes coexisted in the studied waters with PC-SYN cells dominating during spring and PE-SYN during winter and autumn. PC-SYN showed a significant positive relationship with temperature and strong positive responses to nitrogen nutrients, whereas PE-SYN positively responded to phosphate availability. The relative ratio of phosphorus availability and total inorganic nitrogen nutrients (N/P ratio) affects the spatial distribution of the two Synechococcus ecotypes.U radu je istražena raspodjela i brojnost dva ekotipa roda Synechococcus, tzv. stanice bogate fikocijaninom (PC-SYN) i stanice bogate fikoeritrinom (PE-SYN) u površinskom sloju vodenog stupca, tijekom 2015. i 2016. godine. Područje istraživanja obuhvaćalo je nekoliko estuarijskih područja te područje trofičkog gradijenta od obale prema otvorenom moru, širokog raspona temperature mora ((11.82 - 20.75 ^oC)), saliniteta (4.47-38.84) i koncentracije hranjiva. Brojnost PC-SYN bila je u rasponu od ( 0 to 79.79 x 10^ 3 cell mL^-1), a PE-SYN od (5.01 x 10^3 to 76.74 x 10^3 cell mL^-1). Utvrđeno je istovremeno obitavanje oba ekotipa na istraživanom području, s prevladavanjem PC-SYN tijekom proljeća te PE-SYN tijekom zime i jeseni. Pokazana je statistički značajna povezanost između PC-SYN i temperature te njegova jaka pozitivna povezanost s dušikovim spojevima, dok su PE-SYN stanice pozitivno odgovorile na dostupnost fosfata. Relativni omjer dostupnosti fosfora i ukupnih hranjiva dušika (N/P omjer) utjecao je na prostornu raspodjelu oba ekotipa roda Synechococcus

Mixed Ion-Polaron Glasses as New Cathode Materials

Electrical transport in mixed ion-polaron glasses has been investigated in four series of glasses containing transition metal oxides (TMO) namely WO3/MoO3, and Na+/Ag+ ions with the composition xWO3- (30-0.5x)Na2O-(30-0.5x)ZnO-40P2O5, xWO3-(30- 0.5x)Ag2O-(30-0.5x)ZnO-40P2O5, xMoO3-(30-0.5x)Na2O- (30-0.5x)ZnO-40P2O5, and xMoO3-(30-0.5x)Ag2O-(30- 0.5x)ZnO-40P2O5, 0 ≤ x ≤ 60 (mol%). The DC conductivity of Na-glasses up to 30 mol% of WO3 and MoO3 is almost identical due to the dominance of ionic conductivity. In this compositional region, the introduction of tungstate and molybdate units increases the mobility of sodium ions and compensates the decrease in sodium number density. On the other hand, with increasing WO3 and MoO3 content and decreasing Ag+ ion concentration in Ag-glasses the DC conductivity decreases for few orders of magnitude. A significant difference in conductivity is observed for glasses with higher WO3 and MoO3 content. While for glasses containing WO3 the conductivity rapidly increases due to a huge polaronic contribution indicating a turnover from predominantly ionic to polaronic transport, the conductivity for MoO3- glasses decreases in the entire mixed compositional range suggesting dominant ionic transport. The changes in the conduction mechanism with the systematic alternation of the glass composition have been analyzed in correlation with the structural modifications and variations of molybdenum and tungsten in different oxidation states

Structural Properties and Crystallization of Sodium Tellurite Glasses

The structural properties and crystallization behaviour of xNa(2)O-(100-x)TeO(2) (0 <= x <= 33.3, x-% mole fraction) glasses have been investigated by Raman spectroscopy. X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The Raman spectra of glasses show systematic changes in structural units. from TeO(4) trigonal bypiramids ((bps) to TeO(3) trigonal pyramids (tps) with increasing Na(2)O content in glass. These structural changes are result of Te-(eq)O(ax)-Te disruption and the formation of non-bridging oxygens (NBOs) in glass network. When heated at 623 K for 10 h glasses crystallized to different phases: alpha-TeO(2), Na(2)Te(4)O(9) and a new crystalline phase which is believed to be a polymorph of Na(2)Te(2)O(5)

Structural Properties and Crystallization of Sodium Tellurite Glasses

The structural properties and crystallization behaviour of xNa2O-(100-x)TeO2 (0 <= x <= 33.3, x-% mole fraction) glasses have been investigated by Raman spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The Raman spectra of glasses show systematic changes in structural units, from TeO4 trigonal bypiramids (tbps) to TeO3 trigonal pyramids (tps) with increasing Na2O content in glass. These structural changes are result of Te–eqOax–Te disruption and the formation of non-bridging oxygens (NBOs) in glass network. When heated at 623 K for 10 h glasses crystallized to different phases: alpha-TeO2, Na2Te4O9 and a new crystalline phase which is believed to be a polymorph of Na2Te2O5