Investigation of abrasive wear resistance of ferrous-based coatings with scratch tester

Abrasive wear resistance is very important in many applications and in most cases it is directly correlated with hardness of materials. Possible solutions for overcoming poor abrasive wear resistance of light metals, like Al-alloys, is using of coatings. In this paper the investigated results of the two types of ferrous-based coatings were presented and compared with gray cast iron, known as a material with good abrasive wear resistance. Process used for coating deposition on an Al-Si alloy substrate was Atmospheric Plasma Spraying (APS). Scratch tests with diamond indenter were used to simulate abrasive wear process. The indenter velocity of 10 mm/min was used over a wear tracks of 10 mm, with different normal loads applied. Both, coefficient of friction and wear rate of the samples were investigated and analyzed in correlation with its mechanical properties.

Investigation of abrasive wear resistance of ferrous-based coatings with scratch tester

Abrasive wear resistance is very important in many applications and in most cases it is directly correlated with hardness of materials. Possible solutions for overcoming poor abrasive wear resistance of light metals, like Al-alloys, is using of coatings. In this paper the investigated results of the two types of ferrous-based coatings were presented and compared with gray cast iron, known as a material with good abrasive wear resistance. Process used for coating deposition on an Al-Si alloy substrate was Atmospheric Plasma Spraying (APS). Scratch tests with diamond indenter were used to simulate abrasive wear process. The indenter velocity of 10 mm/min was used over a wear tracks of 10 mm, with different normal loads applied. Both, coefficient of friction and wear rate of the samples were investigated and analyzed in correlation with its mechanical properties.

LAMOTRIGINE VERSUS LITHIUM AUGMENTATION OF ANTIDEPRESSANT THERAPY IN TREATMENT-RESISTANT DEPRESSION: EFFICACY AND TOLERABILITY

Background: Mood stabilizer augmentation of standard antidepressant drugs has been shown to be effective in treatment-resistant depression. Despite the reported high overall efficacy, lithium has been relatively underused in recent years. Lamotrigine, a novel anticonvulsant recently recognized as a mood stabilizer, seems to have putative antidepressive properties. The aim of the study was to investigate lamotrigine efficacy and tolerability as antidepressant augmentation for unipolar treatment-resistant depression compared to lithium. Subjects and methods: 88 patients suffering from treatment-resistant Major depressive disorder, having acute recurrent depressive episodes according to DSMIV criteria, were enrolled in the study. This was an open-label trial with a flexible dosing regimen. All patients, received antidepressants in full therapeutic doses. They were divided into two augmentation groups: 46 patients received 50-200 mg/day lamotrigine, and 42 patients received 600-1200 mg/day lithium. The Hamilton Rating Scale for Depression (HAM-D) and The Clinical Global Impression scale (CGI) were used to monitor therapeutic efficacy. Patients were evaluated weekly for an 8 week treatment period. Results: The HAM-D total score was significantly reduced in both treatment groups at the study endpoint, without any difference between the groups. However, significant clinical improvement was reached within the second treatment week in the lamotrigine group compared to the lithium group (p=0.01 vs. lithium). Lamotrigine showed significant efficacy on the HAM-D item 1(depressed mood; p=0.01), item 7 (work and interest; p=0.01) and CGI-Improvement scale (p=0.02). The drop-out rate due to treatment failure was lower in the lamotrigine group (n=1) compared to the lithium (n=4) group. Also, the incidence of side effects did not differ between the groups. Conclusions: Our results suggest that lamotrigine could be useful as augmentation of antidepressants for treatment-resistant unipolar depression. Also, lamotrigine may accelerate the onset of antidepressant action, and therefore might be useful in treatment of major depression in general

Arhuska konvencija kao putokaz za zaštitu od jonizujućeg zračenja pomoću slobodnog pristupa informacijama

Доступност инфомрација свим грађанима и омогућавање њиховог учешћа у процесима заштите, укључујући заштиту од јонизујућих зрачења представља неминовност савременог доба и прихватљив модел поступања. То је законом прописана обавеза органа јавне власти и организација које врше јавна овлашћења. Обавеза информисања јавности је утемељена уставом који ово право прокламује као људско право новије генерације. Право на слободан приступ информацијама од јавног значаја у које недвосмислено потпадају еколошке информације разрађују закони, укључујући Закон о заштити од јонизујућих зрачења и о нуклеарној сигурности. Ради се о праву појединаца које истовремено представља обавезу органа јавне власти у области заштите животне средине. Ово право је пуну афирмацију добило кроз одредбе Архуске конвенције усвојене у јуну 1998.године, коју је Република Србија ратификовала 2009.године. Након њеног доношења и ратификације, национална законодавства по правилу садрже одредбе о слободном приступу еколошким информацијама. Архуска конвенција је значајна не само са аспекта слободног приступа еколошким информацијама већ и у домену еколошке едукације и развијању свести о чувању и заштити природе и њеног окружења. Њена улога је немерљива и у области заштите од јонизујућих зрачења имајући у виду да ће појединци најбоље заштитити своје здравље али и животну средину ако поседују потпуна сазнања и благовремене иноформације о изворима јонизујућих зрачења и опасностима која они са собом носе. Из тога произлази потреба за слободан приступ информацијама о изворима јонизујућих зрачења, дозама зрачења и механизмима заштите у случају прекомерних доза.The availability of information related to the protection of citizens from the sources of ionizing radiation has everyday application. This is a statutory obligation of state organs and other entities that carry out these tasks. Informing the public is prescribed by the Constitution, and this is a human rights law foreseen in the Constitution. This law contains a number of laws including the Law on the Protection of Ionizing Radiation and on Nuclear Safety. It is the right of individuals and at the same time the obligation of state authorities. It is of great importance in the field of environmental protection. In this area, it is most comprehensive in the provisions of the Aarhus Convention adopted in June 1998. This Convention was ratified in 2009 in the Republic of Serbia. After that, all environmental laws contain provisions on free access to environmental information. The Aarhus Convention is important for the environmental education of individuals and for developing awareness of environmental protection. In the case of ionizing radiation protection, it is important that individuals have information about the dangers and possibilities of protection. It is therefore important to have information about sources of ionizing radiation, radiation doses and protection mechanisms in case of overdoses.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Arhuska konvencija kao putokaz za zaštitu od jonizujućeg zračenja pomoću slobodnog pristupa informacijama

Доступност инфомрација свим грађанима и омогућавање њиховог учешћа у процесима заштите, укључујући заштиту од јонизујућих зрачења представља неминовност савременог доба и прихватљив модел поступања. То је законом прописана обавеза органа јавне власти и организација које врше јавна овлашћења. Обавеза информисања јавности је утемељена уставом који ово право прокламује као људско право новије генерације. Право на слободан приступ информацијама од јавног значаја у које недвосмислено потпадају еколошке информације разрађују закони, укључујући Закон о заштити од јонизујућих зрачења и о нуклеарној сигурности. Ради се о праву појединаца које истовремено представља обавезу органа јавне власти у области заштите животне средине. Ово право је пуну афирмацију добило кроз одредбе Архуске конвенције усвојене у јуну 1998.године, коју је Република Србија ратификовала 2009.године. Након њеног доношења и ратификације, национална законодавства по правилу садрже одредбе о слободном приступу еколошким информацијама. Архуска конвенција је значајна не само са аспекта слободног приступа еколошким информацијама већ и у домену еколошке едукације и развијању свести о чувању и заштити природе и њеног окружења. Њена улога је немерљива и у области заштите од јонизујућих зрачења имајући у виду да ће појединци најбоље заштитити своје здравље али и животну средину ако поседују потпуна сазнања и благовремене иноформације о изворима јонизујућих зрачења и опасностима која они са собом носе. Из тога произлази потреба за слободан приступ информацијама о изворима јонизујућих зрачења, дозама зрачења и механизмима заштите у случају прекомерних доза.The availability of information related to the protection of citizens from the sources of ionizing radiation has everyday application. This is a statutory obligation of state organs and other entities that carry out these tasks. Informing the public is prescribed by the Constitution, and this is a human rights law foreseen in the Constitution. This law contains a number of laws including the Law on the Protection of Ionizing Radiation and on Nuclear Safety. It is the right of individuals and at the same time the obligation of state authorities. It is of great importance in the field of environmental protection. In this area, it is most comprehensive in the provisions of the Aarhus Convention adopted in June 1998. This Convention was ratified in 2009 in the Republic of Serbia. After that, all environmental laws contain provisions on free access to environmental information. The Aarhus Convention is important for the environmental education of individuals and for developing awareness of environmental protection. In the case of ionizing radiation protection, it is important that individuals have information about the dangers and possibilities of protection. It is therefore important to have information about sources of ionizing radiation, radiation doses and protection mechanisms in case of overdoses.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Predicting violence in veterans with posttraumatic stress disorder

Background/Aim. Frequent expression of negative affects, hostility and violent behavior in individuals suffering from posttraumatic stress disorder (PTSD) were recognized long ago, and have been retrospectively well documented in war veterans with PTSD who were shown to have an elevated risk for violent behavior when compared to both veterans without PTSD and other psychiatric patients. The aim of this study was to evaluate the accuracy of clinical prediction of violence in combat veterans suffering from PTSD. Methods. The subjects of this study, 104 male combat veterans with PTSD were assessed with the Historical, Clinical and Risk Management 20 (HCR-20), a 20-item clinicianrated instrument for assessing the risks for violence, and their acts of violence during one-year follow-up period were registered based on bimonthly check-up interviews. Results. Our findings showed that the HCR-20, as an actuarial measure, had good internal consistency reliability (α = 0.82), excellent interrater reliability (Interaclass Correlation ICC = 0.85), as well as excellent predictive validity for acts of any violence, non-physical violence or physical violence in the follow-up period (AUC = 0.82-0.86). The HCR-20 also had good interrater reliability (Cohen's kappa = 0.74), and acceptable predictive accuracy for each outcome criterion (AUC = 0.73-0.79). Conclusion. The results of this research confirm that the HCR-20 may also be applied in prediction of violent behavior in the population of patients suffering from PTSD with reliability and validity comparable with the results of previous studies where this instrument was administered to other populations of psychiatric patients

3D tehnika digitalne obrade svetlosti (DLP) primenjena u izradi dvoslojnih tableta: koncept kombinovane polipilule

Ever since 3D printing was introduced to the field of pharmacy, it has caused a paradigm shift from the manufacturing of large-scale to small batches of medicines tailored accordingly to the specific needs of patients. This study aimed to formulate and fabricate two-layered 3D tablets using the digital light processing (DLP) technique. Hydrochlorothiazide (HHT,5%,w/w) and warfarin sodium (WS,5%,w/w) were selected as model drugs. The printing process was initiated with 0.1% of photoinitiator, at a constant ratio of poly(ethylene glycol)diacrylate and poly(ethylene glycol) 400, 1:1, with the addition of water (10%,w/w). Single-layered tablets of 8.00 mm diameter and 1.50 mm thickness, containing HHT and WS respectively, were successfully printed, as well as combined two-layered 3D tablets, with each of the active substances in separate layers. Dissolution tests of single-layered tablets showed immediate, but incomplete release of WS (81.47±1.47%, after 45min), and prolonged and complete release of HHT (98.17±3.11%, after 8h), while significantly slower and incomplete release of both drugs from the combined two-layered 3D tablets was observed. The absence of drug-polymer interaction and presence of a layered cross-sectional tablet structure were confirmed. DLP technique enables simple and rapid fabrication of combined two-layered 3D tablets, while further optimization of formulation factors is necessary to achieve complete drug release.Uvođenje tehnologije 3D štampe u oblasti farmacije uslovilo je razvoj fundamentalnih promena, pri čemu serijska proizvodnja velikih šarži pretenduje da bude zamenjena malim serijama lekova prilagođenih prema specifičnim potrebama pacijenata. Cilj istraživanja bio je da se formulišu i izrade dvoslojne tablete primenom tehnike digitalne obrade svetlosti (DLP). Hidrohlortiazid (HHT, 5%, m/m) i varfarin-natrijum (WS, 5%, m/m) odabrani su kao model lekovite supstance. Proces štampanja sproveden je u prisustvu 0,1% fotoinicijatora, pri konstantnom masenom odnosu poli(etilen glikol)diakrilata i poli(etilen glikola) 400, 1:1, uz dodatak 10% vode. Jednoslojne 3D tablete prečnika 8,00 mm i debljine 1,50 mm, koje sadrže HHT, odnosno WS, kao i kombinovane dvoslojne 3D tablete, sa svakom od aktivnih supstanci u posebnom sloju, uspešno su odštampane. Prilikom ispitivanja brzine rastvaranja lekovite supstance iz jednoslojnih tableta, došlo je do trenutnog (81,47±1,47%, nakon 45 min), ali nepotpunog oslobađanja WS, i produženog i potpunog oslobađanja HHT (98,17±3,11%, nakon 8 h), dok je iz kombinovanih tableta zapaženo znatno sporije i nepotpuno oslobađanje obe lekovite supstance. Potvrđeno je odsustvo interakcija i prisustvo slojevite strukture. DLP tehnika pruža mogućnost jednostavne i brze izrade kombinovanih tableta, pri čemu je dalja optimizacija formulacionih faktora neophodna u cilju postizanja potpunog oslobađanja lekovite supstance

Intramolekulska Barbier-ova reakcija u vodi - sinteza petočlanih i šestočlanih prstenova

Zinc or indium promoted intramolecular Barbier reactions of aldehydes containing a suitably positioned allylic or propargylic halide unit afford unsaturated cyclic alcohols in moderate yields.Aldehidi koji u pogodnom položaju poseduju alil-halogenidnu ili propargil halogenidnu strukturnu jedinicu reaguju u vodenim uslovima sa cinkom ili indijumom, pri čemu nastaju nezasićeni ciklični alkoholi u umerenim prinosima

Halkoni potencijalni inhibitori HIV‐1 proteaze

The discovery of HIV and the study of molecular mechanisms crucial for the virus replication cycle have led to the identification of important protein structures - potential targets of drug action in AIDS therapy. One of the most significant discoveries is HIV-1 protease (PR), an enzyme that plays a key role in the HIV replication cycle (1). This study aimed to test and demonstrate the interactions of newly synthesized chalcones (1,3-diaryl-2- propen-1-one) as well as three commercial drugs (lopinavir, ritonavir and darunavir) in the active site of HIV-1 protease using in sillico methods. and that the results obtained correlate with the results of in vitro tests on the enzyme itself. The twenty structurally similar chalcone derivatives were synthesized and their physico-chemical characterization was performed. Docking calculations were performed using the Autodock Wine program in the 3D structure of the enzime catalytic site (pdb code: 6B36). The inhibition of enzyme activity was monitored by fluorimetric method (2). The obtained results revealed that all compounds showed anti-HIV-1 protease activity. Compound C1 showed the highest inhibitory activity with an IC 50 values of 0.001 μM which is comparable with commercial product Darunavir. The results obtained indicate that the synthesized compounds can be classified as potential anti-HIV-1 protease inhibitors. Further research is focused on testing the ADMET properties of the synthesized compounds as well as the synthesis of their analogues for which in silico tests have shown satisfactory results.Otkrić e HIV-a i istraživanje molekularnih mehanizama ključnih za ciklus replikacije virusa dovelo je do identifikacije važnih proteinskih struktura - potencijalnih ciljnih mesta dejstva lekova u terapiji AIDS-a. Jedno od najznačajnijih otkrića je HIV-1 proteaza (PR), enzim koji ima ključnu ulogu u ciklusu replikacije HIV-a (1). Ova studija imala je za cilj da primenom in sillico metoda ispita i prikaže interakcije novosintetisanih halkona (1,3-diaril-2- propen-1-ona) kao i tri komercijalna leka (lopinavira, ritonavira i darunavira) u aktivnom mestu HIV-1 proteaze i da dobijene rezultate koreliše sa rezultatima in vitro testova na samom enzimu. Sintetisano je dvadeset strukturno sličnih derivata halkona i izvršena njihova fizičko-hemijska karakterizacija. Docking studije izvedene su u programu Autodock Vine u 3D strukturi enzimskog katalitičkog mesta (pdb kod: 6B36). Inhibicija enzimske aktivnosti određena je primenom fluorimetrijske metode (2). Dobijeni rezultati ukazuju da svih 20 jedinjenja ispoljava anti-HIV-1 proteaznu aktivnost. Jedinjenje HNT1 je pokazalo najveć u inhibitornu aktivnost sa vrednostima IC50 od 0,001 μM što je uporedivo sa komercijalnim proizvodom darunavirom. Dobijeni rezultati ukazuju da se sitetisana jedinjenja mogu klasifikovati kao potencijalni anti-HIV-1 proteazni inhibitori. Dalje istraživanje je usmereno na ispitivanju ADMET osobina sintetisanih jedinjenja kao i sintezi njihovih analoga za koje su in silico ispitivanja pokazala zadovoljavajuće rezultate.VIII Kongres farmaceuta Srbije sa međunarodnim učešćem, 12-15.10.2022. Beogra

Radijacioni rizik

Једно од основних питања у области заштите од зрачења је процена прихватљивости ризика од зрачења, што је формулисано и кроз три принципа заштите од зрачења: оправданост, оптимизација и ограничење дозе. Спровођење ових принципа је сложен процес који захтева примену низа активности и вештина из различитих области од правно регулаторних до уско стручних тј. природно техничких или хуманитарно медицинских наука. Почетне тачке у разматрању примене извора зрачења су процена користи тј. добробити од примене извора зрачења и процена радијационог ризика коју та примена носи. У овом раду су такође разматране и вредности доза тј. шта сматрамо високим а шта ниским дозама, приступ процени радијационог ризика као и преглед вредности за неке границе излагања.Having in mind that all human activities carry some sort of risks, one of the main issue of radiation protection is assessment of the acceptability of risks of using radiation sources. This is also, the first step of applying ALARA principle. Risk is a synonym for probability of harmful effect and takes into account probability of happening some events and severity of consequences. This is complicated task in which have to be involved many specialist and skills from different parts of science. The paper discussed some effective dose values, the way of calculation risks from low doses and connection of dose and risks with terms from regular usage such as: high doses, low doses and very low doses.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин