Feasibility study of a current mode gamma radiation dosimeter based on a commercial pin photodiode and a custom made auto-ranging electrometer

An experimental study has been conducted to evaluate the feasibility of a current mode gamma radiation dosimeter, consisting of a commercial PIN photodiode as a radiation sensor, and a custom made auto-ranging electrometer for real-time measurement of the PIN photodiode’s response under radiation exposure. The radiation induced direct current response for single PIN photodiodes with different active areas, as well as for multiple PIN photodiodes connected in parallel, has been investigated. Three types of commercial silicon PIN photodiodes have been chosen for evaluation - S1223, BPW34, and PS100-6-CER2 PIN. During the experiment, five samples have been tested - three samples made of single PIN photodiodes (one sample of each photodiode type) and two samples formed by connecting multiple photodiodes in parallel (two BPW34 photodiodes in parallel and four BPW34 photodiodes in parallel). The samples have been irradiated with a 60Co gamma ray source and the relations between the induced photocurrent and the dose rate, and between the accumulated charge and the absorbed dose, have been determined. For measuring the photodiodes response, a custom made auto-ranging electrometer controlled by a personal computer, and capable of measuring direct currents from 50 pA to 10 mA with relative error less than 2.5%, has been used. Obtained results have shown very good linearity between the dose rate and the induced photocurrent for dose rates ranging from 0.93 Gy/h to 67 Gy/h. Also, very good linearity has been observed between the accumulated charge and the absorbed dose for all tested samples, within the investigated range of absorbed doses from 472 mGy to 3.3 Gy. On the basis of the obtained results, a simple model has been derived, enabling the estimation of the photodiode’s current response as a function of the dose rate and the photodiode’s geometry (active area and depletion layer width). [Projekat Ministarstva nauke Republike Srbije, br. 43011

Schizotypy: Current concepts and future research implications

Shizotipija je konstrukt koji se koristi kako bi se opisala grupa osoba sa simptomima koji ne ispunjavaju kriterijume za postavljanje dijagnoze shizofrenije, ali imaju sličnosti sa ovim kompleksnim i heterogenim psihiajtrijskim oboljenjem. MKB-10 opisuje shizotipiju kao privremeno stanje (shizotipalni poremećaj), dok je DSM-5 opisuje kao trajniji poremećaj (shizotipalni poremećaj ličnosti). S obzirom da se shizotipija prostire kroz normalnu, supkliničku i kliničku populaciju, temeljno teorijsko razumevanje ovog koncepta može biti od pomoći prilikom razvijanja mera procene shizotipije. Do sada, najveći deo psihometrijske evaluacije shizotipije bazirao se na varijetetima individualnih razlika (poremećaja) ličnosti. Ovaj članak se fokusira na evoluciju termina shizotipije, na razumevanje ovog fenomena, mogućnosti psihometrijske procene u skladu sa trenutnim modelima ličnosti i na klinička razmatranja koja bi dovela do poboljšane detekcije i intervencije u ovoj oblasti.Schizotypy is a construct used to describe a group of persons with symptoms which do not fulfill criteria for schizophrenia, but have some similarities with this complex and heterogeneous psychiatric disorder. ICD-10 describes schizotypy as a state (schizotypal disorder), while DSM-5 labels it as a trait marker (schizotypal personality disorder). Considering how schizotypy encompasses through the normal, subclinical and clinical population, a thorough theoretical understanding of this concept could be helpful in developing measures of assessment. So far, most of the tools for psychometric evaluation of schizotypy have focused only on abnormal personality. The present article focuses on the evolution of the term schizotypy, its current understanding, the possibilities of psychometric assessment in relation to contemporary constructs of personality and on clinical considerations for improved detection and intervention in this field

Experimental and numerical study of super-critical flow around the rough sphere

Rad predstavlja eksperimentalno i numeričko istraživanje modela sfere sa ciljem predviđanja ponašanja strujanja u prisustvu hrapavosti površina. Rezultati ukazuju na probleme i predlažu rešenje za inžinjersku primenu. Sličnost između strujnih slika dobijenih numeričkim putem i u aerotunelu je postignuta kombinovanim uvođenjem turbulencije u numeričkoj slobodnoj struji hrapavosti površine, zbog ograničavajućih zahteva turbulentnih modela.This paper presents the experimental and numerical research on the sphere model with the goal of prediction of a flow behaviour in a presence of the surface roughness. Results indicate the problems and suggest the solution for engineering practice. The similarity of the numerical and wind tunnel flows was reached by an application of a combination of the intentionally introduced turbulence intensity in a numerical flow as well the artificial roughness of the model, for a reason of restricted requirements of the turbulence modelling

Experimental and numerical study of super-critical flow around the rough sphere

Rad predstavlja eksperimentalno i numeričko istraživanje modela sfere sa ciljem predviđanja ponašanja strujanja u prisustvu hrapavosti površina. Rezultati ukazuju na probleme i predlažu rešenje za inžinjersku primenu. Sličnost između strujnih slika dobijenih numeričkim putem i u aerotunelu je postignuta kombinovanim uvođenjem turbulencije u numeričkoj slobodnoj struji hrapavosti površine, zbog ograničavajućih zahteva turbulentnih modela.This paper presents the experimental and numerical research on the sphere model with the goal of prediction of a flow behaviour in a presence of the surface roughness. Results indicate the problems and suggest the solution for engineering practice. The similarity of the numerical and wind tunnel flows was reached by an application of a combination of the intentionally introduced turbulence intensity in a numerical flow as well the artificial roughness of the model, for a reason of restricted requirements of the turbulence modelling

Degree of Conversion and Temperature Measurement of Composite Polymerised with Halogen and LED-Curing Unit

Današnji kompozitni materijali polimeriziraju se vidljivim plavim svjetlom valne duljine oko 468 nm. Komercijalni uređaji za polimerizaciju kompozitnih materijala emitiraju plavo svjetlo različite jakosti. Uporaba uređaja za polimerizaciju jačega intenziteta sa svrhom da se postigne veći stupanj konverzije neminovno povećava zagrijavanje i temperaturu u materijalu tijekom stvrdnjavanja te polimerizacijski skuplja materijal. Svrha rada bila je utvrditi postoji li razlika između stupnja konverzije i porasta temperature triju ispitivanih kompozitnih materijala: Amelogen (Akeda Dental, Danska), Pertac II (ESPE, Seefeld, Germany), Z100 (3M Dental Products, St. Paul, Minessotta, USA), polimeriziranih eksponencijskim programom Elipar Trilight (ESPE, Seefeld, Njemačka) polimerizatora i Lux-o-Max (Akeda Dental, Danska) uređajem za polimerizaciju temeljenog na LED (light emitting diodes) tehnologiji. Rezultati su pokazali tek nešto niži stupanj konverzije pri polimerizaciji Lux-o-Max uređajem u odnosu prema eksponencijskome programu Elipar Trilight polimerizatora. Temperaturni porast znatno je niži pri polimerizaciji Lux-o-Max uređajem za sve ispitivane kompozitne materijale u usporedbi s rezultatima dobivenima pri polimerizaciji eksponencijskim programom Elipar Trilight polimerizatora.Today available composite materials are polymerized by blue light, with a wavelength of about 468 nm. Commercially available curing units for composite resin polymerization emit blue light of different intensity. Using curing units of higher light intensity to reach a higher degree of conversion unavoidably leads to higher temperature rise in material during hardening, and also to polymerization shrinkage of material. The aim of this study was to determine if there is any difference between the degree of conversion and temperature rise in three composite materials: Amelogen (Akeda Dental, Denmark), Pertac II (ESPE, Seefeld, Germany) and Z100 (3M Dental Products, St. Paul, Minessotta, USA) polymerized with exponential program of Elipar Trilight curing unit (ESPE, Seefeld, Germany) and Lux-o-Max curing unit (Akeda Dental, Denmark) based on LED (light emitting diodes) technology. The results showed only a slightly lower degree of conversion, in the case of polymerization with Lux-o-Max curing unit. The temperature rise was significantly lower in the case of polymerization with Lux-o-Max curing unit for all tested composite materials

Electroclinical characteristics of MRI negative focal epilepsy: A video-EEG study

Background/Aim. Epileptogenic lesions carry intrinsic epileptogenicity or epileptogenic potential in their close vicinity. One third of patients with focal epilepsy have no epileptogenic lesions magnetic resonance imaging [MRI(-)]. The aim of this study was to determine the epileptogenic zone investigating electrical and clinical properties of MRI-patients. Methods. In 180 patients with focal epilepsy we analyzed 1,712 seizures for interictal and ictal electroencephalography (EEG) and seizure semiology. If multiple seizures occurred we took the best seen on video as an example, with secondary generalized tonic-clonic seizures (GTCS) if it occurred. Brain MRI was focused to investigate the zone of ictal EEG onset. Electroclinical properties of the MRI-patients were compared to lesion positive patients [MRI(+)]. Results. A single epileptogenic lesion was identified in 68.89% [hippocampal sclerosis (HS) in 58, focal cortical dysplasia (FCD) in 28 and other pathologies in 38 patients]. MRI(-) patients had significantly less interictal epileptiform abnormalities, and presented more often (p lt 0.001) with secondary GTCS as the only seizure. Eye opening, hypermotor seizure, bilateral asymmetric clonic seizure, vocalization, and contralateral body turning occurred more frequently in the MRI-group compared to the MRI+ one. MRI-patients share some semiological features with FCD as opposed to HS patients. Conclusion. MRIepilepsy patients frequently present with electroclinical features seen in frontal lobe epilepsy or in epilepsy associated with FCD

Intraoperacijska primjena autotransfuzije kao metoda smanjenja potrošnje homologne krvi kod operacije aneurizme abdominalne aorte Intraoperative use of autotransfusion as a method of saving homologous blood during abdominal aortic aneurysm repai

Uvod: Otvorena rekonstrukcija aneurizme abdominalne aorte pripada skupini kirurških zahvata tijekom kojih se očekuju veliki gubici krvi. Postoji potreba za razvojem strategija čija je svrha smanjenje korištenja homologne krvi. Cilj rada: Cilj rada opis je epidemiološke analize bolesnika operiranih zbog abdominalne aneurizme metodom otvorene rekonstrukcije, uz analizu koristi intraoperacijske primjene stroja za autotransfuziju u sklopu primjene strategije smanjenja potrošnje homologne krvi u perioperacijskom periodu. Metode i ispitanici: Provedena je retrospektivna studija bolesnika koji su operacijski liječeni metodom otvorene rekonstrukcije abdominalne aorte u Kliničkoj bolnici Dubrava od 1.1. do 31.12.2015. godine. Uključeno je 59 bolesnika. Postupak intraoperacijske autotransfuzije primijenjen je u svih bolesnika prema standardiziranom protokolu za Medtronic AutoLog System. Obrađena krv transfundirana je bolesnicima u intraoperacijskom periodu. Analizirana je demografska struktura bolesnika, ukupna količina krvi aspirirane i obrađene uređajem za autotransfuziju, količina primijenjene homologne krvi te transfuzija krvnih pripravaka u formi svježe smrznute plazme. Rezultati: Prosječna starost ispitanika iznosila je 66,79 godina, 71% bolesnika bilo je starije od 65 godina, 80% bolesnika bilo je muškog spola. Kod ukupno 6,8% bolesnika nije bilo dovoljno krvi aspirirane iz operacijskog polja za daljnje procesuiranje strojem za autotransfuziju, dok je kod 93,2% bolesnika prosječna količina aspirirane krvi iznosila 2383 ml. (288-8420). Analizom povezanosti opsežnosti krvarenja i starosti bolesnika utvrđena je slabo pozitivna povezanost, r= 0,101 uz p= 0,33. Prosječna količina krvi koja je retransfundirana bolesnicima iznosila je 800 ml (0-3160). Homolognu krv dobilo je ukupno 17% bolesnika, prosječne količine 1072 (460-1800). Od ukupnog broja bolesnika 18% ih je dobilo svježe smrznutu plazmu, u prosjeku 877 ml (460-1030). Zaključak: Intraoperacijska autotransfuzija je učinkovita metoda uštede autologne i smanjenja potrošnje homologne krvi

Antifungalana aktivnost biljnih etarskih ulja i odabranih sojeva Pseudomonas spp. na Phomopsis theicola

Development of natural plant protection products as an alternative to synthetic fungicides is of significant importance regarding the environment. This study was carried out with an objective to investigate in vitro antifungal activities of several essential oils extracted from oregano, basil, myrtle and Turkish pickling herb, and the plant growth-promoting rhizobacteria in the genus Pseudomonas, against the phytopathogenic fungus Phomopsis theicola. Microdilution methods were used to determine the minimum inhibitory concentrations (MIC) of selected antimicrobial essential oils (EOs). All EOs exhibited significant levels of antifungal activity against the tested fungal isolates. The oregano EO was found the most potent one (MIC - 5.5 µg/mL), followed by basil (MIC - 75.0µg/mL), myrtle (MIC - 775 µg/mL) and Turkish pickling herb (MIC - 7750 µg/mL). Inhibition of Ph. theicola mycelial growth was observed for all tested Pseudomonas spp. strains. K113 and L1 strains were highly effective and achieved more than 60% of fungal growth inhibition using the overnight culture and more than 57% inhibition by applying cell-free supernatants of both strains. A future field trial with K113 and L1 cultures and cell-free supernatants, containing extracellular metabolites toward Ph. theicola, will estimate their effectiveness and applicability as an alternative to chemical protection of apple trees.U novije vreme intezivno se radi na razvoju bioloških sredstava za zaštitu bilja, koja bi se uvodila kao zamena za sintetičke fungicide. U ovom radu ispitivan je in vitro antifungalni uticaj nekih etarskih ulja (EU) i odabranih rizobakterija koje stimulišu rast biljaka iz roda Pseudomonas na fitopatogenu gljivu Phomopsis theicola. Minimalne inhibitorne koncentracije (MIC) etarskih ulja su određene mikrodilucionom metodom. Sva primenjena EU su ispoljila značajni antifungalni efekat na ispitivani izolat gljive. EU origana je ispoljilo najnižu MIC od 5.5±0.51 µg/mL, zatim ulje bosiljka od 75.0±5.7 µg/mL, mirte 775±45.0 µg/mL i turske kisele biljke od 7750±4.5 µg/mL. Proučavan je stepen inhibicije porasta micelije Ph. theicola primenom različitih sojeva Pseudomonas spp. sojevi K113 i L1 su ispoljili visoku efikasnost inhibicije od preko 60% primenom dvadesetčetvoročasovnih kultura i preko 57% primenom filtrata supernatanta. U narednim ogledima u polju primenom kulture i supernatanta K113 i L1, koji sadrže ekstracelularne metabolite, proceniće se njihova efikasnost i mogućnost korišćenja kao alternative hemijskim sredstvima u zaštiti jabuke od Ph. theicola