1,721,097 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
SINERGISTIC ANTIBIOFILM EFFECT OF SELECTED ESSENTIAL OILS ON LEGIONELLA PNEUMOPHILA
No full textLegionella pneumophila je gram negativna bakterija koju nalazimo u različitim prirodnim vodenim sredinama, kao i u umjetnim vodenim sustavima. Udisanjem aerosola inficiranog legionelama kod čovjeka se razvija pontijačka groznica ili teška legionarska bolest. Uz sve veću svijest o legionelozi povezanoj uz korištenje bazena i jacuzzi bazena, redovito čišćenje i dezinfekcija postaju ključan rizični faktor u širenju infekcije. Osim topline i dezinfekcije klorom, alternativna antibakterijska sredstva kao što su eterična ulja ekstrahirana iz raznih biljaka sve se više procjenjuju. Stoga je cilj ovog istraživanja utvrditi sinergistički antilegionela učinak između odabranih eteričinih ulja te sinergistički učinak eteričnih ulja u sprječavanju formiranja biofilma kako bi se uspostavila alternativna metoda dezinfekcije vode. Korišteno je eterično ulje lavandina, ružmarina i smilja, a ispitivanje je provedeno metodom šahovnice uz upotrebu mikrotitarskih ploča.
Dobiveni rezultati pokazuju sinergističko i aditivno djelovanje navedenih eteričnih ulja. Minimalna inhibicijska koncentracija eteričnog ulja ružmarina iznosi 12,8 mg/mL, dok minimalna inhibicijska koncentracija eteričnih ulja lavandina i smilja iznosi 3,2 mg/mL. Kada su eterična ulja pokazala sinergistički učinak bile su potrebne puno niže koncentracije (0,05 – 0,8 mg/mL) za suzbijanje legionela nego kada je djelovalo samo jedno eterično ulje. Navedena eterična ulja pokazala su i sinergistički učinak kod sprječavanja formiranja biofilma. Zaključno najbolje djelovanje pokazala je kombinacija eteričnog ulja lavandina i ružmarina.Legionella pneumophila is a gram negative bacterium found in different natural water environments, as well as in artificial water systems. Inhalation of aerosol infected with Legionella develops in a man a Pontiac fever or a severe Legionaires disease. With the growing awareness of legionellosis associated with usage of pools and jacuzzi, regular cleaning and disinfection become a key risk factor for spreading infection. In addition to heat and chlorine disinfection, alternative antibacterial agents such as essential oils extracted from various plants are increasingly evaluated. Therefore, the aim of this study is to determine the synergistic anti-Legionella effect between selected essential oils and the synergistic effect of essential oils in preventing biofilm formation in order to establish an alternative water disinfection method. Essential oil of lavender, rosemary and immortelle was used, and the examination was carried out using the chessboard method with the usage of microtiter plates.
The obtained results show the synergistic and additive affect of these essential oils. The minimum inhibitory concentration of rosemary essential oil is 12.8 mg/mL, while the minimum inhibitory concentration of lavender and immortelle essential oils is 3.2 mg/mL. When essential oils produced a synergistic effect, much lower concentrations (0.05 to 0.8 mg/mL) were needed to suppress Legionella than when only one essential oil was in used. These essential oils have also shown a synergistic effect in preventing biofilm formation. In conclusion, the best anti - Legionella effect was shown by a combination of lavender and rosemary essential oil
PHOTOCATALYTIC ACTION OF ZINC OXIDE ON FOODBORNE BACTERIA
No full textHranom prenosive bolesti jedne su od najučestalijih bolesti u svijetu. Uzrokuju ih razni mikroorganizmi koji se prenose hranom i vodom za piće. U ovom istraživanju promatran je antibakterijski učinak fotoaktiviranog cinkovog oksida na šest patogena koji se prenose hranom od kojih su 3 predstavnici gram-pozitivnih, a 3 predstavnici gram – negativnih bakterija. Spektrofotometrijski utvrđene koncentracije bakterijskih suspenzija od 106 CFU/mL izlagane su UV svjetlosti valne duljine 366 nm 3 i 5 minuta u prisustvu cinkovog oksida nanesenog na polimerni nosač, a učinkovitost cinkovog oksida uspoređena je s učinkovitosti samog nosača i UV svjetlosti. Bakterijska suspenzija nasađena je na Mueller Hinton agar tehnikom nakapavanja 2 sata i 24 sata kasnije. Eksperiment je ponovljen kako bi se utvrdio učinak na bakterijsku adheziju na polimerne nosače. Nosači su sonificirani u ultrazvučnoj kupelji i dobivena suspenzija je nasađena na agar. Nakon inkubacije od 24 sata, brojene su kolonije. Rezultati pokazuju da fotoaktivirani cinkov oksid ima statistički značajno bolje djelovanje na gram – negativne bakterije. Najotpornija bakterija je Staphylococcus aureus, a najosjetljivija je Escherichia coli. Usporedba učinka polimernih nosača s cinkovim oksidom sa i bez fotoaktivacije UV svjetlom potvrđuje da je učinak statistički značajan nakon 3 i 5 minuta u preživljavanju i broju adheriranih bakterija. Nakon 24 sata fotokatalitički učinak nije statistički značajan što se može pripisati odgođenim učincima UV – a i oksidacijskog stresa.Foodborne diseases are one of the most common illnesses in the world. They are caused by various microorganisms distributed by food or potable water. In this research, antibacterial effect of photoactivated zinc oxide was observed on six foodborne pathogens, three Gram negative, and three Gram positive. Spectrophotometrically determined bacterial suspension of 106 CFU/mL was exposed to UV light at wavelength 366 nm for 3 and 5 minutes with zinc oxide applied to polymer carrier, and the effectiveness of zinc oxide was compared to the carrier and UV light on their own. Bacterial suspension was plated on Mueller Hinton agar using drop plate technique 2 and 24 hours after exposure. The experiment was repeated to determine the effect on bacterial adhesion to the polymer. Polymer carriers were sonicated in an ultrasound bath and the acquired suspension was plated. After 24 hours of incubation, colonies were counted for results. Results show that photoactivated zinc oxide has a statistically significant effect on Gram negative bacteria. The most resistant bacterium was Staphylococcus aureus, and the most susceptible bacterium was Escherichia coli. Comparison of effect between polymer carriers with zinc oxide with and without UV light photoactivation confirms that the effects of photoactivation are statistically significant after both 3 and 5 minutes in bacterial survival and adherence to carriers. After 24 hours there was no significant effect which could be due to postponed effects of UV radiation and oxidative stress
POTENTIAL ENVIRONMENTAL SOURCES OF LEGIONELLA INFECTIONS
No full textBakterije iz porodice Legionellaceae jedni su od najčešćih uzročnika atipičnih upala pluća. L. pneumophila, zajedno s L. longbeachae, uzročnik je 90% infekcija bakterijama iz roda Legionella. Bakterije iz ove porodice su ubikvitarne pa ih možemo pronaći i u antropogenim i u biogenim sustavima. Izolirane su iz različitih izvora u okolišu poput rijeka, mora i tla. Legioneloze predstavljaju značajan javnozdravstveni problem, a na njihovom suzbijanju se aktivno radi. Unatoč svim naporima legioneloze, u koje ubrajamo legionarsku bolest i pontijačku groznicu, se često ne dijagnosticiraju, a ukoliko se dijagnoza postavi, izvor zaraze u većini slučajeva ostaje nepoznat. Već niz godina poznati su nam klasični izvori infekcije poput rashladnih tornjeva, bazena s pjenom, sljepih završetaka cijevi, ovlaživača zraka i slično. Osobit problem predstavlja biofilm koji se stvara u takvom okruženju. Legionele parazitiraju u amebama, što ih čini otpornijima na dezinfekciju. Postoje mnoge preventivne mjere koje se provode za suzbijanje razmnožavanja legionela i sprječavanje obolijevanja od legioneloza.
U ovom radu skupljeni su podaci iz istraživanja vezanih za prisutnost legionela u kompostu i mješavinama tla, kišnici, termalnim izvorima, moru i otpadnim vodama. Također, kod izvora gdje je zabilježena zaraza, obrađeni su pojedinačni prikazi slučajeva. Za sve navedene izvore, osim mora, zabilježeni su slučajevi obolijevanja. Za razliku od uobičajenih izvora zaraze, točan put prijenosa i mjere suzbijanja za većinu okolišnih izvora nisu detektirani. Ovo istraživanje pokazalo je veliku rasprostranjenost legionela u okolišu te potrebu za daljnim istraživanjima njihovih potencijalnih staništa.Bacteria from the Legionellaceae family are one of the most common causative agents of atypical pneumonia. L. pneumophila, together with L. longbeachae, is the cause of 90% of infections with bacteria of the genus Legionella. Bacteria from these families are ubiquitous and can be found in anthropogenic and biogenic systems. They are isolated from various environmental sources such as rivers, sea and soil. Legionellosis is a significant public health problem, and we are actively working to combat it. Despite all the efforts legionellosis, which includes legionnaires ’disease and pontiac fever, are often undiagnosed, and when a diagnosis is set, the source of the epidemic often remains unknown. For many years, we have known classic sources of infections such as cooling towers, foam pools, blind pipe ends, humidifiers and others. A particular problem is the biofilm that forms in such environment. Legionella parasitize in amoebae, which makes it resistant to disinfection. There are many preventive measures that are implemented to suppress the reproduction of legionela and prevent the disease of legionellosis.
This paper collects data from research related to the presence of legionela in compost and soil mixtures, rainwater, thermal springs, sea and wastewater. Also, for sources where cases were recorded, individual case reports have been explained. For all listed sources, except the sea, cases of the disease have been reported. Unlike conventional sources of legionellosis, accurate transmission pathaways and control measures for most environmental sources are not detected. This research showed the high prevalence of Legionella in the environment and the need for further research into potential Legionella habitats
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Antibacterial effect of Thieves universal cleanser on bacteria of the genus Staphylococcus and Acinetobacter
No full textAlternativna antimikrobna sredstva koja posjeduju dezinfekcijska svojstva zauzimaju sve veću pažnju u usporedbi s tradicionalnim dezinfekcijskim sredstvima. Alternativna sredstva često se smatraju manje toksičnima, ekološki prihvatljivijima i prirodnijima. U ovu skupinu spada i Thieves univerzalno sredstvo za čišćenje. Ključni sastojci ovog sredstva su neionski površinski aktivni agensi, anionski tenzidi i esencijalno ulje Thieves. Eterično ulje Thieves je terapijska kombinacija 5 esencijalnih ulja: Eugenia caryophyllus (klinčić), Citrus limon (limun), Cinnamomum zeylanicum (cimet), Rosmarinus officinalis (ružmarin) i Eucalyptus radiata (eukaliptus). Ova koncentrirana formula pogodna za gotovo svaku površinu uključujući tepihe, podove, staklo i zidove.
Cilj ovoga rada bio je ispitati antibakterijsko djelovanje univerzalnog sredstva za čišćenje Thieves na bakterije roda Staphylococcus aureus i Acinetobacter baumannii.
Korištene su dvije metode: metoda difuzije u agar iz rupica i metoda određivanja antimikrobnog djelovanja u određenom vremenu u kojem je mjerena je djelotvornost tri različito pripremljene otopine u vremenskom rasponu od 1, 3, 5, 10, 15, 20, 30 minuta. ispitivale su se tri različita pripravka, Thieves i ocat, Thieves i voda te voda i ocat. Sva tri pripravka pokazuju različite antimikrobni učinak. Otopina a) (Thieves i voda) pokazuje najslabije antibakterijsko svojstvo, dok otopina b) (Thieves i ocat) pokazuje najjače antibakterijsko svojstvo prema svim sojevima.
Zaključno, Thieves univerzalno sredstvo za čišćenje pokazuje značajni antimikrobni učinak na bakterije roda Staphylococcus i Acinetobacter, posebice kombinacija Thieves-a i octa te samim time ima veliki potencijal kao alternativno sredstvo za čišćenje koje može zamijeniti grube kemikalije.Compared with traditional disinfectants, alternative antimicrobials have been given increasingly more attention. Alternative agents are often considered less toxic, more environmentally friendly and more natural. This group includes Thieves Household Cleaner. The key ingredients of this cleaner are non-ionic surface active agents, anionic surfactants and Thieves Essential Oil. Thieves Essential Oil is a therapeutic combination of 5 essential oils: Eugenia caryophyllus (clove), Citrus limon (lemon), Cinnamomum zeylanicum (cinnamon), Rosmarinus officinalis (rosemary) i Eucalyptus radiata (eucalyptus). This concentrated formula is suitable for almost every surface, including carpets, floors, glass and walls.
The aim of this research was to examine the antibacterial effect of the universal cleaning agent Thieves on bacteria of the genera Staphylococcus aureus and Acinetobacter baumannii.
Two methods were used: the method of diffusion into agar from the holes and the method of determining antimicrobial activity at a given time in which the efficacy of three differently prepared solutions was measured in a time range of 1, 3, 5, 10, 15, 20, and 30 minutes. Three different solutions were used: Thieves and vinegar, Thieves and water, and water and vinegar. All three solutions show different antimicrobial effects. Solution a) (Thieves and water) exhibits the weakest antibacterial property, while solution b) (Thieves and vinegar) exhibits the strongest antibacterial properties for all strains.
In conclusion, Thieves Household Cleaner shows significant antimicrobial effects on bacteria of the genera Staphylococcus and Acinetobacter, especially the combination of Thieves and vinegar, and thus has great potential as an alternative cleaning agent that can replace coarse chemicals
THE INFLUENCE OF ESSENTIAL OILS OF LEMON EUCALYPTUS AND TEA TREE AND THEIR COMBINATIONS ON THE BIOFILM OF LEGIONELLA PNEUMOPHILA
No full textKontrola bakterije legionela u vodoopskrbnim sustavima predstavlja sve veći prioritet za zdravstvo. Tretiranje vode zagađene legionelom je bitno, a obično se koriste brojni pristupi koji nekada nisu unčikoviti protiv samih biofilmova. Legionela je rasprostranjena, patogena bakterija koja svojom virulencijom može uzrokovati niz zaraza od kojih neke mogu biti veoma opasne. Uglavnom se prenosi vodom, točnije aerosolom koji je kontaminiran bakterijama. Najkritičnija polazišta zaraze stoga predstavljaju distribucijski vodovodni sustavi. Eterična ulja su prirodni spojevi dobiveni iz dijelova biljaka koji nalaze sve češću primjenu u svakodnevnom životu ljudi. Osim što svojim mirisom aromatiziraju prostor, istovremeno djeluju antivirusno i antibakterijski.
Kako su saznanja o uporabi eteričnih ulja kao prirodnih dezinficijensa oskudna, cilj ovog rada je odrediti antibakterijski učinak kombinacije eteričnih ulja čajevca i limunskog eukaliptusa na biofilmove koje stvara ova bakterija.
U svrhu ovog istraživanja koristila se L. pneumophila (soj 130b) koja je uzgajana na BCYE podlozi. Ispitivanje se temeljilo na tri odvojena eksperimenta kako bi se ispitala sinergija ulja, inhibicijsko djelovanje ulja na adheziju na polistiren odnosno na prvi korak stvaranja biofilma i na inhibiciju samog stvaranja biofilma. Testirana eterična ulja čajevca i limunskog eukaliptusa su dobivena iz firme Dea Flores d.o.o.
Dobiveni rezultati pokazuju različito, ali učinkovito djelovanje kombinacija eteričnih ulja. Zaključno, možemo reći da antibakterijska svojstva ulja uvelike ovise o sinergističkom djelovanju eteričnih ulja jednog s drugim kao i o samim kemijskim sastavnicama koja čine ta eterična ulja. Na ulja koje smo mi ispitivali legionela je pokazala osjetljivost, stoga spajanjem ugodnog egzotičnog mirisa s korisnim antibakterijskim djelovanjem, eterična ulja pokazuju dobar alternativan način zaštite i prevencije.Control of bacteria Legionella in water supply systems is an increasing priority for healthcare all around the world. Legionella is a widespread, pathogenic bacteria that can cause a variety of infections with its virulence, some of them can be very dangerous. Legionella is mainly transmitted by water, specifically by aerosol contaminated by bacteria. The most critical starting points for this bacteria are the distribution water supply systems. Essential oils are natural compounds obtained from parts of plants and are increasingly used in everyday life. Apart from the fact that their fragrance aromatizes the space, they simultaneously act antivirally and antibacterial. As the knowledge about the use of essential oils as natural disinfectants is scarce, the aim of this study is to determine the antibacterial effect of a combination of essential oils of tea and lemon eucalyptus on the biofilm created by this bacterium. For the purpose of this study, L. pneumophila (strain 130b) was grown on BCYE substrate. The study was based on three separate experiments to investigate the effect of essential oils on the destruction of the created biofilm, the inhibition of adhesion to the polystyrene, the first step in the formation of biofilm and on the inhibition of biofilm formation. Tested essential oils of tea and lemon eucalyptus were obtained from Dea Flores d.o.o. The results obtained show a different but effective effect of a combination of essential oils. In conclusion, we can say that the antibacterial properties of oil depend largely on the synergistic effect of essential oils with each other as well as on the chemical components that make these essential oils. The oils we tested on L. pneumophila showed sensitivity, therefore by combining a pleasant exotic fragrance with useful antibacterial activity, essential oils show a good alternative way of protection and prevention
PHOTODYNAMIC EFFECT OF CATIONIC PORPHYRIN TMPyP3 ON RESISTANT BACTERIA IN MUNICIPAL WASTEWATER
No full textFotodinamička inaktivacija jedna je od obećavajućih metoda suzbijanja širokog spektra osjetljivih, ali i rezistentnih bakterija koje postaju glavnim javnozdravstvenim problemom današnjice. Svrha ovog rada jest ispitati učinkovitost fotodinamičke inaktivacije u suzbijanju otpornih bakterija u komunalnim otpadnim vodama upotrebom kationskog hidrofilnog porfirina TMPyP3 u kombinaciji sa zračenjem ljubičaste LED lampe intenziteta 40 mW/cm2. Fotodinamički učinak ispitan je određivanjem minimalne efektivne koncentracije (MEK) TMPyP3 i provedbom fotoinaktivacijskog testa. Ispitivanje je izvršeno na rezistentnim sojevima Pseudomonas aeruginosa i Burkholderia cepacia izoliranim iz biofilma unutar bolničkih ustanova te P. aeruginosa, Pseudomonas putida i Vibrio parahaemolyticus izoliranim iz uzorka komunalne otpadne vode. Testiranja su provedena na uzorcima sterilne vode iz slavine, sterilne otpadne vode te sirove otpadne vode. Usporedbom rezultata zaključeno je da učinkovitost TMPyP3 ovisi o karakteristikama ispitivanog soja i mehanizmima rezistencije (MEK za multirezistentni P. aeruginosa u uzorku sterilne otpadne vode je ˃100 μM, a MEK za osjetljivi soj P. aeruginosa pri istim uvjetima je ˃12 μM). Osim toga, fotoinaktivacijskim testom utvrđeno je da je učinkovitost TMPyP3 u inhibiciji multirezistentnog P. aeruginosa u sirovoj otpadnoj vodi smanjena zbog prisustva drugih bakterija (% inhibicije P. aeruginosa u sirovoj otpadnoj vodi ≈ 89% u odnosu na ≈ 92% u sterilnoj otpadnoj vodi) te da se produljenjem vremena zračenja učinkovitost ispitivanog porfirina povećava pri nižim koncentracijama.Photodynamic inactivation is one of the promising methods of combating a wide range of suspectible, but also resistant bacteria that are about to become a major problem in field of public health. The aim of this study was to investigate the effectiveness of photodynamic inactivation on resistant bacteria in municipal wastewater using cationic hydrophilic porphyrin TMPyP3 in combination with purple LED lamp with the intensity of 40 mW/cm2. The photodynamic effect was investigated by determining the miminum effective concentration (MEC) of TMPyP3 and photoinactivation testing. The study was carried out on multiresistant strains Pseudomonas aeruginosa and Burkholderia cepacia isolated from biofilm inside of hospital facilities and P. aeruginosa, Pseudomonas putida and Vibrio parahaemolyticus isolated from municipal wastewater. The tests were done on samples of sterile tap water, sterile wastewater and raw wastewater. By comparing the results, it was concluded that the effectiveness of TMPyP3 depends on the characteristics of tested strains and resistance mechanisms ( MEC for multidrug resistant P. aeruginosa in a sterile wastewater sample is ˃ 100 μM and MEC for suspectible P. aeruginosa under the same conditions is ˃ 12 μM). In addition, the results of photoinactivation test revealed that the efficacy of TMPyP3 in inhibition of multidrug resistant P. aeruginosa in raw wastewater sample was reduced due to the presence of other bacteria (% of inhibition of multiresistant P. aeruginosa in raw wastewater sample is ≈89% in comparison to ≈92% of inhibition in sterile wastewater) and that by prolongation of the irradiation time, the efficiency of the tested porphyrin increases at lower concentration
- …
