59 research outputs found

    Antimicrobial Activities of Essential Oil and Methanol Extract of Teucrium montanum

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    This study was designed to examine the chemical composition of essential oil and the in vitro antimicrobial activities of essential oil and methanol extract of Teucrium montanum. The inhibitory effects of essential oil and methanol extracts of T. montanum were tested against 13 bacterial and three fungal species by using disc-diffusion method. GC/MS analyses revealed that essential oil contains mainly δ-cadinene (17.19%), β-selinene (8.16%) α-calacorene (4.97%), 1,6-dimethyl-4-(1-methylethyl)-naphthalene (4.91%), caryophyllene (4.35%), copaene (4.23%), torreyol (3.91%), 4-terpineol (3.90%), cadina-1,4-diene (3.39%), β-sesquiphellandrene (3.34%), τ-cadinol (3.12%) and γ-curcumene (3.18%). The essential oil has antibacterial as well as antifungal effect

    Computational modeling of shear forces and experimental validation of endothelial cell responses in an orbital well shaker system

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    Vascular endothelial cells are continuously exposed to hemodynamic shear stress. Intensity and type of shear stress are highly relevant to vascular physiology and pathology. Here, we modeled shear stress distribution in a tissue culture well (R = 17.5 mm, fill volume 2 ml) under orbital translation using computational fluid dynamics with the finite element method. Free surface distribution, wall shear stress, inclination angle, drag force, and oscillatory index on the bottom surface were modeled. Obtained results predict nonuniform shear stress distribution during cycle, with higher oscillatory shear index, higher drag force values, higher circular component, and larger inclination angle of the shear stress at the periphery of the well compared with the center of the well. The oscillatory index, inclination angle, and drag force are new quantitative parameters modeled in this system, which provide a better understanding of the hydrodynamic conditions experienced and reflect the pulsatile character of blood flow in vivo. Validation experiments revealed that endothelial cells at the well periphery aligned under flow and increased Kruppel-like Factor 4 (KLF-4), cyclooxygenase-2 (COX-2) expression and endothelial nitric oxide synthase (eNOS) phosphorylation. In contrast, endothelial cells at the center of the well did not show clear directional alignment, did not induce the expression of KLF-4 and COX-2 nor increased eNOS phosphorylation. In conclusion, this improved computational modeling predicts that the orbital shaker model generates different hydrodynamic conditions at the periphery versus the center of the well eliciting divergent endothelial cell responses. The possibility of generating different hydrodynamic conditions in the same well makes this model highly attractive to study responses of distinct regions of the same endothelial monolayer to different types of shear stresses thereby better reflecting in vivo conditions

    Digital image correlation in analysis of stiffness in local zones of welded joints

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    Ponašanje zavarenih spojeva u lokalnim zonama, kao i njihov uzajamni utjecaj, jedan je od glavnih problema u projektu zavarene konstrukcije. Naime, osnovni je problem u određivanju mehaničkih svojstava materijala u zavarenom spoju. Ta su svojstva neophodna za točan proračun zavarenih konstrukcija. Mogućnost dobivanja vrijednosti lokalne deformacije/pomaka čini tehniku "Digital Image Correlation" (DIC) pogodnom za ispitivanje zavarenog spoja i određivanje mehaničkih svojstava. Tijekom ovih ispitivanja za opterećenje je korišten uređaj za vlačnu provjeru, a dvije kamere su korištene za 3D analizu deformacije. Upotrijebljen je uzorak s paralelnim stranama dobiven zavarivanjem V spoja. Prije ispitivanja izvršeno je kalibriranje kako bi se dobili što točniji rezultati. U radu je predstavljena primjena DIC tehnike korištenjem Aramis softvera za mjerenje lokalnog pomaka/deformacije u zavarenom spoju. Dobiveni rezultati pokazuju da je zavareni spoj bio nejednako deformiran s prednje i zadnje strane korijena, u području elastične deformacije, tijekom vlačnog opterećenja. Zbog vlaka u uzorku s V-zavarom (osnovni materijal S235JRG2, žica elektrode - VAC 60), postoji uzajamni utjecaj mehaničkih svojstava lokalnih zona, gdje je krutost korijena zavara najviša.The behaviour of welded joints in local zones, as well as their mutual influence, represents one of the main challenges in welded structure design. Namely, the main issue lies in determining the mechanical properties of materials in a welded joint. These properties are necessary for an accurate calculation of welded structure integrity. The possibility of obtaining local strain/displacement values makes the "Digital Image Correlation" (DIC) technique suitable for welded joint testing and determining of mechanical properties. In this paper a tensile testing machine was used for loading and a two camera system was used for 3D strain analysis. A specimen with parallel sides, obtained by welding of a V joint was used. Calibration was performed prior to testing, in order to ensure dimensional consistency of the system. Application of DIC technique using Aramis software for measuring local displacement/strain in a welded joint is presented in this paper. Due to tension in the V-weld specimen (Base material - S235JRG2, electrode wire - VAC 60), mutual influence of mechanical properties of local zones is present, wherein the root weld had the highest stiffness

    Performance Analysis of Industrial Cooperative Communication System in Generalized Fading Environment

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    This paper considers the performance analysis of M-ary phase shift keying industrial cooperative relaying system in Nakagami-m multipath fading channel with Gamma shadowing, which is known as the Generalized-K composite fading channel. Since the paper deals with the industrial environment, the communication channel is also affected by the additive Middleton\u27s Class-A impulsive noise. The bit error rate is used as a performance measure and the closed-form average bit error rate expression was derived. The influence of different fading and noise parameters on the system performance is investigated. The obtained results may be used for the improvement of the present and future industrial wireless communication systems

    Usability testing of our library’s new website

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    Since the University of Zurich required all departments to use the same content management system, a makeoverof our Main Library’s website was planned for 2017. Following Steve Krug’s book Don’t make me think, revisited,we reduced the contents and tried to build an easy to understand and straightforward navigation for the users. Toverify our concept, we arranged “do-it-yourself” usability tests. Three test sessions with three persons each weresufficient to find out what had to be improved on the website, and were more helpful than hours of discussionamong the team. Usability testing helped us to understand our customers' search behaviour and expectations fornavigation. It was also entertaining and a novel way of interacting with our customers

    A giant exulcerated phyllodes breast tumor a case report

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    © 2020, University of Kragujevac, Faculty of Science. All rights reserved. Phyllodes tumors of the breast can be benign, malignant, or borderline. Benign and borderline tumors are rare tumor types that have a positive outlook and high survival rate, while the risk of recurrence is typical for malignant breast tumors. Giant phyllodes tumors are larger than 10 cm in diameter and demand a serious diagnostic and treatment approach. In this study we present a case of a female patient treated for an exulcerated breast carcinoma-a giant borderline phyllodes tumor of the breast. The patient presented to the department for the right breast lump with ulcerated skin and nipple abnormalities. The core biopsy was performed and the patient was diagnosed with a benign tumor. Simple mastectomy was performed and final histopathological report revealed a borderline phyllodes tumor. Diagnosis and treatment of a giant phyllodes tumor remain a great challenge for the surgeons. Establishing the preoperative diagnosis based on histopathological findings is imperative to disease management. Surgery is the mainstay of treatment and mastectomy has been the traditional procedure; in cases where suspicious findings in the axilla are revealed, radical mastectomy is performed and the axilla is to be dissected

    ANALYSIS OF THE COMPLIANCE OF THE MEDICAL WASTE MANAGEMENT PROCESS IN THE COUNTRIES OF THE WESTERN BALKANS AND THE EU

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    From a global perspective, the negative consequences of the medical waste impact on human health and the environment are becoming increasingly intensified nowadays. On the one hand, these consequences are manifested as infections, injuries and diseases, while on the other hand they cause soil, water and air contamination with pollutants from medical waste. The aim of this paper is to define the principles of a medical waste management programme within medical institutions. By analysing the previous research on medical waste, the paper gives a systematic presentation of the definition, classification and labelling of medical waste, as well as the ecotoxicological risk to the environment and health, thus creating a basis for reviewing the strategies of the management program for this type of waste. Based on the analysis of the available data on generated medical waste in a given territory, the measures of adequate medical waste management can be applied with the aim of eliminating or minimizing the negative consequences of this waste on human health and the environment. A comparative qualitative analysis of medical waste was conducted in the paper. In addition, applying the analysis of the potential methods of medical waste treatments indicated the importance of selecting strategies for medical waste management, which was observed from several perspectives. The defined principles for the implementation of a medical waste management programme represent the key result of this study. The paper provides an overview of the tools for drafting the waste management plan, as well as an example of a diagram intended to support the decision-making on the treatment methods to be used in the absence of appropriate regional infrastructures

    LTE AND WIFI CO-EXISTENCE IN 5 GHZ UNLICENSED BAND

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    Since the future mobile networks will require significantly higher data throughput, and the Long-Term Evolution (LTE) licensed bands are already occupied, the frequency band extension and the data rate increase may be achieved by using some of the available unlicensed bands. The most appropriate unlicensed band for this purpose lies in 5 GHz frequency range. However, this unlicensed band is already occupied by WiFi networks and a special attention has to be paid to coordinate these two different networks in the shared spectrum usage. Therefore, this paper considers the shared access co-existence in 5 GHz unlicensed band between uncoordinated LTE and WiFi networks. More precisely, it considers the influence of the LTE downlink transmission on the performance of the WiFi networks. The experimental results show that the LTE significantly degrades the WiFi network performance, which means that some of the coordination algorithms have to be employed

    Is Balint training associated with the reduced burnout among primary health care doctors?

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    The aim of our study was to examine whether the participation in Balint group is associated with the reducing burnout syndrome among primary health care doctors. This investigation was conducted on a population of 210 doctors employed in primary health centers in Belgrade. Out of 210 doctors, 70 have completed Balint training for a period of at least 1 year, whereas 140 doctors have never attended this training (the Non-Balint group). The level of burnout among physicians was assessed with the Serbian translation of the original 22- item version of the Maslach Burnout Inventory – Human Services Survey which defines burnout in relation to emotional exhaustion, depersonalization and personal accomplishment. We found that 45.0% of the Non-Balint participants and 7.1% of the Balint-trained participants responded with symptoms of high level of emotional exhaustion, with a statistically significant difference (p < 0.001). In relation to depersonalization, 20% of the Non-Balint subjects were highly depersonalized compared to 4.4% of the Balint-trained subjects, with a statistically significant difference (p < 0.001). Regarding the personal accomplishment, 21.4% of the Non-Balint subjects and 7.1% of the Balint-trained subjects had a perception of low personal accomplishment, with a statistical significance (p < 0.001). In the multiple ordinal logistic model, with emotional exhaustion as a dependent variable, statistically significant predictor was female gender (OR = 2.51; p = 0.021), while Balint training was obtained as a protective factor (OR = 0.12; p < 0.001). Non-specialists were detected as a risk factor for depersonalization (OR = 2.14; p = 0.026) while Balint group was found as a protective factor (OR = 0.10; p < 0.001), according to the multiple ordinal logistic regression analysis. Regarding the reduced personal accomplishment, our results indicated that nonspecialists were at risk for this subdimension (OR = 2.09; p = 0.025), whereas Balint participants were protected (OR = 0.18; p < 0.001). Participation in Balint groups is associated with the reduced burnout syndrome among primary health care doctors.Keywords: Doctor-patient relationship; Balint groups; burnout; primary health care; patientcentered; approac

    Three-dimensional biomechanical model of benign paroxysmal positional vertigo in the semi-circular canal

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    Benigna paroksizmalna pozicijska vrtoglavica (BPPV) je najčešći poremećaj vestibularnog sustava koji uzrokuju bazofilne čestice u polukružnom kanalu. Trodimenzijski biomehanički model SCC je opisan s potpunom 3D interakcijom fluid-struktura, čestica, zidova, deformacije kupule i endolimfnog strujanja fluida. Prikazan je model SCC s parametarskim definiranim dimenzijama i trodimenzijskim 3D rekonstrukcijama određenog pacijenta. Korištene su pune Navier-Stokes jednadžbe s jednadžbama kontinuiteta opisuje tok fluida dok je Arbitrary-Lagrangian Eulerian (ALE) formulacija korištena za gibanje mreže. Korištena je interakcija fluid-struktura za spajanje tekućine s deformacijom kupule. Primijenjen je algoritam za praćenje čestica. Korištene su različite veličine i broj čestica sa svojom punom interakcijom između sebe, zida i deformacije kupule. Raspodjela brzina, smičnog naprezanja i sila od strane endolimfe je prikazana kao parametar za jedan SCC kao i za tri SCC od određenog pacijenta. Svi modeli se koriste u korelaciji s istim eksperimentalnim protokolima s pokretima glave i gibanjem očiju - nystagmus. Puna interakcija fluid-struktura, čestica otoconia, zidova, deformacije kupula i endolimfnog fluida u tri dimenzije dat će više detalja za razumijevanje patologije specifičnog pacijenta u standardnoj kliničkoj dijagnostici i proceduri terapije za BPPV.Benign Paroxysmal Positional Vertigo (BPPV) is one of the most common vestibular disorders occuring due to the presence of basophilic particles in the semicircular canals (SCC). Three-dimensional biomechanical model of the SCC is described with full 3D fluid-structure interaction of particles, wall, cupula deformation and endolymph fluid flow. The model of the SCC with parametric defined dimension and fully 3D three SCC from patient specific 3D reconstruction is presented. Navier-Stokes equations with continuity equations described fluid flow while Arbitrary-Lagrangian Eulerian (ALE) formulation is used for mesh motion. Fluid-structure interaction for fluid coupling with cupula deformation is used. Particle tracking algorithm has been used for particle motion. Different size and number of particles with their full interaction between themselves, wall and cupula deformation are used. Velocity distribution, shear stress and force from endolymph side are presented for parametric one SCC and patient specific three SCC. All the models are used for correlation with the same experimental protocols with head moving and nystagmus eye tracking. Full fluid-structure interaction of otoconia particles, wall, cupula deflection and endolymph flow in three-dimension give more details and understanding of the pathology of the specific patient in standard clinical diagnostic and therapy procedure for BPPV
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