Simulation of crack propagation in titanium mini dental implants (MDI)

Unapređenja u proizvodnji mini dentalnih implantata (MDI) su uglavnom usmerena ka povećanju njihove biokompatibilnosti i, u isto vreme, izdržljivosti i bezbednosti, ali i ka smanjenju njihovih dimenzija u odnosu na postojeće implantate. Međutim, tokom ugradnje MDI-a može doći do njegovog loma ili nastanka prsline koja kasnije može prouzrokovati lom. Da bi se analiziralo širenje prsline u titanijumskom MDI-u, korišćeni su softveri za primenu metode konačnih elemenata (MKE) ANSYS v13 i FRANC3D v5. Korišćenjem FRANC3D programa izmodelirane su prsline različitih veličina i oblika na 3D geometriji MDI-a i izvršeno je simuliranje njihovog širenja. Na osnovu rezultata simulacije izračunat je približan zamorni vek oštećenog MDI-a.Developments in mini dental implants (MDI) manufacturing are aimed at making them more biocompatible and, at the same time, lighter, more durable and simultaneously safer than the existing implants. But, occasionally, during installation the failure of MDI may occur or cracks may appear, which could lead to the later failure of MDI. In order to understand and assess crack growth in titanium MDI, Finite Element (FE) software packages ANSYS v13 and FRANC3D v5 have been used. Using FRANC3D software different crack sizes and shapes have been modeled and simulations of crack propagations in three-dimensional model of MDI have been performed. Based on simulation results, the approximate fatigue life of damaged MDI was calculated

Simulation of crack propagation in titanium mini dental implants (MDI)

Unapređenja u proizvodnji mini dentalnih implantata (MDI) su uglavnom usmerena ka povećanju njihove biokompatibilnosti i, u isto vreme, izdržljivosti i bezbednosti, ali i ka smanjenju njihovih dimenzija u odnosu na postojeće implantate. Međutim, tokom ugradnje MDI-a može doći do njegovog loma ili nastanka prsline koja kasnije može prouzrokovati lom. Da bi se analiziralo širenje prsline u titanijumskom MDI-u, korišćeni su softveri za primenu metode konačnih elemenata (MKE) ANSYS v13 i FRANC3D v5. Korišćenjem FRANC3D programa izmodelirane su prsline različitih veličina i oblika na 3D geometriji MDI-a i izvršeno je simuliranje njihovog širenja. Na osnovu rezultata simulacije izračunat je približan zamorni vek oštećenog MDI-a.Developments in mini dental implants (MDI) manufacturing are aimed at making them more biocompatible and, at the same time, lighter, more durable and simultaneously safer than the existing implants. But, occasionally, during installation the failure of MDI may occur or cracks may appear, which could lead to the later failure of MDI. In order to understand and assess crack growth in titanium MDI, Finite Element (FE) software packages ANSYS v13 and FRANC3D v5 have been used. Using FRANC3D software different crack sizes and shapes have been modeled and simulations of crack propagations in three-dimensional model of MDI have been performed. Based on simulation results, the approximate fatigue life of damaged MDI was calculated

Urban deciduous tree leaves as biomonitors of trace element (As, V and Cd) atmospheric pollution in Belgrade, Serbia

Leaves of common deciduous trees: horse chestnut (Aesculus hippocastanum) and linden (Tilia spp.) from three parks within the urban area of Belgrade were studied as biomonitors of trace element (As, V, and Cd) atmospheric pollution. The May–September trace element accumulation in the leaves, and their temporal trends, were assayed in a multi-year period (2002–2006). Significant accumulation in the leaves was evident for As and V, but not so regularly for Cd. Slightly decreasing temporal trends of V and As ac-cumulated in the leaf tissues were observed over the years. During the time span, the concentrations of Cd remained approximately on the same level, except in May 2002 and September 2005, when a rapid increase was observed. The May–September accumulations of As and V were higher in horse chestnut than in linden, although both may be used as biomonitors for these elements, and optionally for Cd in conditions of its high atmospheric loadings

Experimental Model for Assessing the Possible Radioprotective Effect of Plant Extract

Tc-99m-radiofarmaceutici se koriste u različitim dijagnostičkim procedurama u nuklearnoj medicini. Da bi se minimizirali štetni efekti jonizujućeg zračenja na zdrava tkiva, intenzivno se istražuju radioprotektivne osobine biljnih ekstrakata. Ljuska ploda crnog oraha sadrži mešavinu različitih farmakološki aktivnih jedinjenja kojа imaju antioksidativno dejstvo i za koje se pretpostavlja da mogu imati i potencijalno radioprotektivno dejstvo. U tom kontekstu, cilj rada je bio da se proceni radioprotektivni efekat ekstrakta ljuske ploda crnog oraha. U ovoj studiji primenjen je eksperimentalni model koji se zasnivao na proceni uticaja ekstrakta na biodistribuciju Tc-99m-radiofarmaceutika po organima eksperimentalnih životinja (pacovi). Ekstrakt ljuske crnog oraha doveo je do smanjenognakupljanja Tc-99m-radiofarmaceutika u pojedinim organimapacova. Rezultati dobijeni na osnovu eksperimentalnog modela sugerišu moguću upotrebu ekstrakta ljuske ploda crnog oraha kao radioprotektivnog sredstva u slučajevima planiranog izlaganja jonizujućem zračenju u nuklearnoj medicini.Tc-99m-radiopharmaceuticals are used in various diagnostic procedures in nuclear medicine. In order to minimize the harmful effects of ionizing radiation on healthy tissues, the radioprotective properties of plant extracts are intensively researched. J. nigra husk contains a mixture of various pharmacologically active compounds that have an antioxidant effect and which are assumed to have a potential radioprotective effect. In this context, the aim of the work was to evaluate the radioprotective effect of black walnut husk extract. In this study, an experimental model was applied, which was based on the assessment of the effect of the extract on the biodistribution of Tc-99m-radiopharmaceuticals in the organs of experimental animals (rats). Black walnut husk extract led to a decrease in the accumulation of Tc-99m-radiopharmaceutical in certain organs of rats. The results obtained on the basis of the experimental model suggest that it is possible to use black walnut husk extract as a radioprotective agent in cases of planned exposure to ionizing radiation in diagnosticsnuclear medicine.XXXII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, 4-6. oktobar 2023; Budva, Crna GoraProceedings: [https://vinar.vin.bg.ac.rs/handle/123456789/11602

Comparative analisys of clinical and microbiological finding in patients with denture stomatitis

Protezni stomatitis je često oboljenje kod pacijenata koji koriste totalne zubne proteze. Uglavnom protezni stomatitis nije praćen simptomima i pacijenti nisu svesni prisutnog oboljenja. Etiologija proteznog stomatitisa je multifaktorijalna. Kao dominantan faktor ističe se infekcija gljivama roda Candida. Totalne zubne proteze podležu kolonizaciji i formiranju biofilma Candida spp. Protezni plak (biofilm) je sličan dentalnom plaku i služi kao rezervoar potencijalno infektivnih mikroorganizama. Mikroorganizmi iz proteznog plaka, (najviše Candida spp.) su odgovorni za nastanak proteznog stomatitisa. Kontinuirano gutanje mikroorganizama iz proteznog plaka izlaže pacijente riziku od neočekivane infekcije. ajčešća izolovana vrsta gljive na protezama je C. albicans. Prisutni su opšti i lokalni kontributivni faktori. Lokalni faktori su: lezije oralne sluzokože uzrokovane neadekvatnim protezama, neprekidno nošenje zubne proteze, smanjen protok pljuvačke, loša higijena zubne proteze, vrsta materijala od koga je izrađena proteza, starost proteze, slaba retencija proteze, neizbalansirana okluzija. Opšti faktori su: diabetes mellitus, pušenje, dugotrajna primena antibiotika i kortikosteroida, radio i hemoterapija, faktori ishrane – nedostatak vitamina B12, folata i gvožđa, psihotropni lekovi, hiposalivatori. Cilj ovog istraživanja je bio da se pouzdano dijagnostikuje i odredi učestalost proteznog stomatitisa gljivične etiologije i ispita antifungalna aktivnost etarskih ulja. Za potrebe ovog istraživanja dizajniran je poseban upitnik, koji sadrži generalije, medicinsku i stomatološku istoriju i podatke dobijene kliničkim pregledom. Klinički pregled se sastojao od inspekcije usne duplje, na osnovu koga se dijagnostikovala inflamacija mekih tkiva, kao i stepen i lokacija inflamacije. Analizom postojećeg stanja totalne zubne proteze u ustima pacijenta utvrđivan je stepen retencije zubne proteze, očuvanost vertikalne dimenzije okluzije i okluzalni odnosi sa antagonistima. Deo istraživanja je sproveden u laboratoriji...Denture stomatitis is a common disease in patients with dentures. Generally, denture stomatitis is not followed by any symptoms and patients are usually not aware of the disease. Etiology of denture stotmatitis is multifactorial. As a dominant factor is the fungal infection by Candida spp. Complete dentures are susceptible to colonization and biofilm formation of Candida spp. Denture plaque (biofilm) is similar to a dental plaque and it is a reservoir of potential infective microorganisms. Microorganisms in denture plaque, (mostly Candida spp.) are responsible for the emergence of denture stomatitis. A continual swallowing of microorganism from denture plaque exposes patients to a risk of unexpected infection. The most common isolated species of fungus on dentures is C. albicans. There are some general and local contributory factors. The local factors are: trauma of oral mucosa caused by inadequate dentures, continuous dentures wearing, reduced saliva flow, bad dentures hygiene, type of the material dentures are made of, detures’age, poor dentures retention, unbalanced occlusion. The general factors are: diabetes mellitus, smoking, long antibiotics and corticosteroids application and radio or chemotherapy, diet factors, - lack of vitamin B12, foliates and iron, psychotropic medications and hyposalivators. The aim of this research has been to diagnose and designate a frequency of denture stomatitis of fungal etiology and examine antifungal activities of essential oils. For the needs of this research there has been designed a special questionnaire which contains .personal data, medical and stomatological history and data obtained by clinical examination. Clinical examination consisted of inspection of oral cavity on the basis of which a soft tissue inflammation has been diagnosed as well as a degree and location of the inflammation. Analysing the present state of complete dentures in patients’ mouth there has been established a degree of denture retention, preservation of vertical dimension of occlusion and occlusal relations with antagonists..

A Prospective Study of Mid-Trimester MCP-1 Levels as a Predictor of Preterm Delivery

Background: The prevention of preterm delivery (PTD) represents one of the major topics in modern obstetrics. The aim was to design a prospective study and investigate if mid-trimester serum and amniotic fluid levels of MCP-1 could predict the occurence of spontaneous PTD. Methods: The study involved 198 women who underwent genetic amniocentesis and blood sampling in the middle of their trimester. After applying the criteria for inclusion in the study, there were 16 respondents in the study group, and 38 respondents in the control group. Level of MCP-1 in amniotic fluid and serum was measured with commercially available enzyme-linked immunosorbent assays (ELISA) and statistical analysis was conducted. Results: There was no statistically significant difference in serum or amniotic fluid MCP1 levels between PTD and the control groups. Conclusion: The results suggest that MCP-1 is probably not the most relevant marker for predicting PTD. This study provides new normative data for MCP-1 levels in amniotic fluid and maternal sera and is a valuable tool for future diagnostic and comparative studies

Antimicrobial and Toxic Effects of Boswellia serrata Roxb. and Mentha piperita Linn. Essential Oils on Vaginal Inhabitants

Commercial essential oils (EOs) of incense, Boswellia serrata Roxb, and mint, Mentha piperita L., were investigated against vaginal bacterial and Candida albicans isolates for antimicrobial potential and safety use. The antimicrobial activity of EOs was investigated through a double-dilution micro-plate assay. A brine shrimp assay was used for the determination of toxicity, while the determination of the chemical composition of EOs was carried out using GS–MS. Obtained minimal inhibitory (MIC) and minimal bactericidal concentration (MBC) point to the activity of mint essential oil (EO) against the multi-resistant P. aeruginosa isolate (MIC/MBC at 6.25 µL/mL), while MIC and MBC values for other isolates were reached at higher concentrations (25–50 µL/mL). According to the toxicity assay, the incense EO reached the LC50 value at 3.07 µL/mL, while mint EO showed higher toxicity at lower concentrations (0.5 µL/mL) and the LC50 could not be determined. The highest antimicrobial potential was obtained for incense against P. aeruginosa. Although the toxicity assay showed high toxicity of mint EO to the eggs of aquatic crustaceans Artemia salina, further testing of EO toxicity is proposed, for example on healthy cell-lines. According to the GC/MS spectrometry, the most represented components of mint EO were the oxygenated hydrocarbons L-menthone (20.86%) and menthol (31.86%), and they could be proposed for further antimicrobial and toxicity investigation

Uticaj PET ambalaže na sadržaj antimona u flaširanim vodama za piće

Antimony trioxide (Sb2O3) is the most frequently used catalyst in the polyethylene terephthalate (PET) manufacture. As a result, antimony is incorporated into PET bottles at concentration level of 100-300 mg/kg. PET containers are used for drinking water and beverages, as well as food packaging and in the pharmaceutical industry. Thus, it is important to understand the factors that may influence the release of antimony from the catalysts into water and other products, since antimony is potentially toxic trace element. In this paper, the antimony content in nine brands of bottled mineral and spring water from Serbia, and seven brands of bottled mineral and spring water from EU countries was analyzed. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS) technique. In the all examined samples the antimony concentration was bellow the maximum contaminant level of 5 μg/L prescribed by the Serbian and EU regulations. Comparison of the content of antimony in PET bottled waters with the content of antimony in water bottled commercially in glass and the natural content of antimony in pristine groundwaters, provides explicit evidence of antimony leaching from PET containers. Since waters bottled in PET have much greater concentration ratio of Sb to Pb than corresponding pristine groundwaters, it can be assumed that bottled waters cannot be used as the relevant source for the study of the natural antimony content in groundwaters. There is a clear relation between the quality of water in bottles (composition, ion strength) and antimony leaching rate. Moreover, while the rate of antimony leaching is slow at temperatures below 60°C, at the temperature range of 60-80°C antimony release occurs and rapidly reaches maximum contaminant level. As antimony can cause both acute and chronic health problems, factors that promote the increase of antimony concentration should be avoided.U ovom radu je ispitivan sadržaj antimona u uzorcima flaširanih mineralnih i izvorskih voda sa domaćeg tržišta, kao i sa tržišta nekih zemalja Evropske Unije, primenom indukovano spregnute plazme sa masenom spektrometrijom. Ispitivanja su vršena sa ciljem da se utvrdi u kojoj meri PET ambalaža utiče na povećanje njegove koncentracije u flaširanim vodama, imajući u vidu da antimon, koji sama ambalaža sadrži, spada u grupu potencijalno toksičnih elemenata. Dobijeni rezultati pokazali su da uzorci voda flaširani u PET ambalaži uvek sadrže antimon u većoj koncentraciji u odnosu na odgovarajuće uzorke koji nisu bili flaširani u PET ambalaži. I pored činjenice da dolazi do otpuštanja antimona iz PET ambalaže, ni u jednom od ispitanih uzoraka voda sadržaj antimona nije prevazilazio maksimalno dozvoljene vrednosti regulisane propisima o kvalitetu vode za piće i kvalitetu flaširanih voda Republike Srbije i Evropske Unije

Thyroid C cells of middle-aged rats treated with estradiol or calcium

The structure and function of C cells of middle-aged female rats (14-months old) treated with estradiol dipropionate (EDP), calcium (Ca) or a combination of EDP+Ca were studied. A stereological method was used to determine the volume of calcitonin (CT)-immunoreactive C cells and their nuclei, and the relative volume density and mean number of the C cells per section were calculated. Serum levels of CT, osteocalcin, parathyroid hormone (PTH), and beta-estradiol were also measured. A significant decrease in body weight of the rats treated with EDP or EDP+Ca was observed. These treatments led to a significant decrease in cellular and nuclear volumes, relative volume density, and mean number of C cells per section, in comparison with the corresponding controls. A reduction of the serum level of CT, PTH, and osteocalcin was also recorded in EDP-and EDP+Ca-treated animals. No statistically significant differences between Ca- and vehicle-injected rats, with regard to all morphometric C cell parameters and biochemical values determined, were seen. However, a conspicuous degranulation of the C cells and decreased immunoreactivity for CT in the Ca-receiving group, which could be interpreted as the signs of increased activity of these cells, were noticed. This effect of Ca was also observed in rats injected with EDP and Ca in combination, when the inhibitory effect of EDP on C cell function was less noticeable than in the group treated with EDP alone.nul

Thyroid C cells of middle-aged rats treated with estradiol or calcium

The structure and function of C cells of middle-aged female rats (14-months old) treated with estradiol dipropionate (EDP), calcium (Ca) or a combination of EDP+Ca were studied. A stereological method was used to determine the volume of calcitonin (CT)-immunoreactive C cells and their nuclei, and the relative volume density and mean number of the C cells per section were calculated. Serum levels of CT, osteocalcin, parathyroid hormone (PTH), and beta-estradiol were also measured. A significant decrease in body weight of the rats treated with EDP or EDP+Ca was observed. These treatments led to a significant decrease in cellular and nuclear volumes, relative volume density, and mean number of C cells per section, in comparison with the corresponding controls. A reduction of the serum level of CT, PTH, and osteocalcin was also recorded in EDP-and EDP+Ca-treated animals. No statistically significant differences between Ca- and vehicle-injected rats, with regard to all morphometric C cell parameters and biochemical values determined, were seen. However, a conspicuous degranulation of the C cells and decreased immunoreactivity for CT in the Ca-receiving group, which could be interpreted as the signs of increased activity of these cells, were noticed. This effect of Ca was also observed in rats injected with EDP and Ca in combination, when the inhibitory effect of EDP on C cell function was less noticeable than in the group treated with EDP alone.nul