Circuital and Numerical Models for Calculation of Shielding Effectiveness of Enclosure with Apertures and Monitoring Dipole Antenna Inside

In this paper, circuital and numerical models of metal In this paper, circuital and numerical models of metal enclosure with apertures are considered for the purpose of accurate shielding effectiveness calculation. An improved circuital model is presented to account for the presence of receiving dipole antenna which is often used in practice to measure the level of electromagnetic field at selected points inside the enclosure. Receiving antenna of finite dimensions could significantly change the EM field distribution inside the enclosure and thus affect the results for SE. TLM method incorporating wire node is used to create a numerical model. Both models are compared in terms of their ability to account for receiving antenna impact on shielding effectiveness of rectangular enclosure with aperture. In addition, comparison of both models is carried out for the case when an array of apertures with different aperture separation is present on one of the enclosure walls whereby the numerical TLM model is additionally enhanced with compact air-vent model

[Eine modifizierte arbeitstechnik bei direkter Pulpauberkappung — unsere Erfahrung]

Direktno prekrivanje pulpe je već davno poznati način kojim se pokušava lečiti obolela zubna pulpa. Najpoznatija i ujedno najprihvatljivija tehnika rada je ona kod koje se iz srebrnog lima izrađuje kapica i stavlja iznad eksponiranog mesta pulpe, lako tehnika rada dobro štiti zubnu pulpu od vanjskih pritiska , ipak se ne može reći da je i najidealnija. Ona se može primeniti isključivo kod velikih i pristupačnih kaviteta. Prema tome za eksponirane pulpe u malim i nepristupačnim kavitetima trebalo je pronaći jednostavniji način rada. U uvodu ovog rada su opisane i predradnje, važne za uspešan tretman pulpe. To je priprema kaviteta, odstranjivanja karioznog dentina iznad pulpe, te aplikacija i adaptacija leka na eksponiranu pulpu. Zatim je opisana tehnika rada prekrivanja pulpe izradom metalne kapice, te njena dobra i loša svojstva. Modificirana tehnika rada kod direktnog prekrivanja pulpe navedena u ovom radu izvodi se isključivo mekim fosfatnim cementom. Kod do njih zuba sa velikim i pristupačnim kavitetima se jednostavno prelivanjem cementa prekriva adaptirani lek. Kod kaviteta gornjih zuba i drugih teže pristupačnih kaviteta rad se izvodi tako što se mekim fosfatnim cementom u manjim porcijama izrađuje venac oko samog leka. Zatim se pojedinim porcijama istog cementa premošćuje venac prilepljivanjem tih porcija sa jednog na drugi kraj venca i to sve dotle dok se ne prekrije sav adaptirani lek. Pomenuti venac pričvršćuje lek u kavitetu i omogućuje da se njegovim premošćivanjem i nanašanjem cementa, prekrije lek bez ikakvog pritiska. Ovom modifikacijom tehnike rada se postiže isti efekat kao i kod one sa izradom metalne kapice. Po našem mišljenju ova modifikacija je univerzalnija i za terapeute u praksi prihvatljivija.Direct pulp capping is long used in the treatment of diseased pulps. The best known and at the same time the most acceptable technique is the one where the capping is done with a silver-plate and placed above the exposed pulp. Although this technique protects the dental pulp very well from external pressure, it can not, however, be said that it is the most ideal method. It may be applied exclusive lyiniarge and easily accessible cavities. For exposed pulps in small and inaccessibie cavities, a simpler method had to be found. In the introductory part of the paper prelim inary steps are described which are im portant for the succesful treatment. This is the preparation of cavities, removal of the carious dentin above the pulp and application and adaptation of the drug at the exposed pulp. The technique of pulp capping by means of a metal cap is described and the good and bad sides of this method are listed. The m odified technique in direct pulp capping mentioned ih this paper is carried out w ith soft phosphate cement exclusively. In the lower teeth w ith Iarge and accessible cavities simple pouring over of cement serves to cover the adapted drug. In cavities of the upper jaw and other less accessible cavities the work is done that a ring is first made by adding small portions of soft phosphate cement around the very drug. Subsequently individual portions of the same cement are used to bridge the ring by adhesion of these portions from one to the other end of the ring until the entire quantity of the drug is covered. The aforementioned ring firmly secures the drug in the cavity and renders it possible to cover the drug without the slightest pressure by bridging and adding of cement. This m odification of the technique of work tends to achieve the same defect as the technique of pulp capping by means of a metal cap. In our opinion this modification is more universal and much more acceptable in the dental practice.Eingangs werden alle Vorarbeiten die fur eine erfolgreiche Pulpabehandlung in Betracht kommen, beschrieben. Die bekannteste Arbeitsmethode fur die direkte Pulpauberkappung besteht in der Uberkappung der geoffneten Pulpa mit einer Kappe aus Silberblech. Doch diese Technik ist nur bei grossen und gut zuganglichen Kavitaten anwendbar. Fur exponierte Pulpen in kleinen und schwer zuganglichen Kavitaten musste eine einfachere Arbeitsweise angewendet werden. Die modifizierte Arbeitstechnik besteht in der Anwendung von weichem Phosphatzement, mit welchen das Heilmittel uberdeckt wird. Bei schwer zuganglichen Kavitaten wird das Zement vorerst kranzfomig um das Heilmittel gelegt. Sodann wird der Kranz ebenfalls, mit Phosphatzement von einer Seite zur anderen uberbruckt, bis das Heilmittel vollstandig uberdeckt ist. Auf diese Art und Weise ist es moglich das Heilmittel ganz ohne Druck zu uberdecken. Diese Modifikation ermoglicht den gleichen Effekt wie mit einer Metallkappe, daher sind wir der Meinung, dass sie fur die allgemeine Praxis geeignet ist

Enhancing the spectral gap of networks by node removal

Dynamics on networks are often characterized by the second smallest eigenvalue of the Laplacian matrix of the network, which is called the spectral gap. Examples include the threshold coupling strength for synchronization and the relaxation time of a random walk. A large spectral gap is usually associated with high network performance, such as facilitated synchronization and rapid convergence. In this study, we seek to enhance the spectral gap of undirected and unweighted networks by removing nodes because, practically, the removal of nodes often costs less than the addition of nodes, addition of links, and rewiring of links. In particular, we develop a perturbative method to achieve this goal. The proposed method realizes better performance than other heuristic methods on various model and real networks. The spectral gap increases as we remove up to half the nodes in most of these networks.Comment: 5 figure

[Der Nutzeffekt des phosphatzements als unterlage fur kavitaten]

Ovim se radom želelo osvežiti pitanje podlaganja kaviteta. Poznato je naime da se kaviteti podlažu zato da bi se zubna pulpa zaštitila od hemijskih i termičkih insulta, koji nastaju kod raznih ispuna kaviteta. Cilj rada je bio da se na što jednostavniji način preispita propusnost za tečnost nekih fosfatnih cemenata, koji se koriste za podlaganje kaviteta. Ovim bi se analogno došlo i do toga da se vidi koliko su ti cementi dobri kao hemijski izolatori kod podlaganja kaviteta, koji se ispunjavaju silikatnim cementima ili samovezujućim akrilatima . Ispitivanja su vršena jednostavnim eksperimentima i to: 1. Na sveže ekstrahiranim zubima rađena su podlaganja u pripremljenim lavitetima sa mekom, srednje tvrdom i tvrdom konzistencijom, fosfatnih cemenata Galenika, Harvardi DentalfiIIigsa. Propusnost ovih cemenata kojim su vršena podlaganja, posmatrana su apsorpcijom obojene tečnosti karbol-fuksina kroz cementnu podlogu u dentinu. 2. Na pripremljene blokove iz fosfatnih cemenata stavljana je određena količina (po dve kapi), plavog mastila. Apsorpcijom mastila u samu masu cemenata određivana je propusnost ovih materijala. Ova dva eksperimenta nisu pokazivala identične rezultate, izuzev srednje tvrde konzistencije fosfatnog cementa »Racim« , koja je u oba slučaja bila nepropusna za obojene tečnosti. »Harvard« fosfatni cement se pokazao isto tako dosta dobar. Naime, slabo je propuštao obojene tečnosti (si. 5 a, b ). Fosfatni cement »Galenika« je, naročito kod drugog pokusa, pokazivao veliku propustnost za obojene tečnosti. Dalja istraživanja u ovom pravcu, i istraživanja drugih autora će pokazati potpunije i tačnije rezultate o kvalitetu ovih fosfatnih cemenata .The aim of this work as to review the problem of cavity lining. It is a well known fact that cavities are lined in order to protect the dental pulp from chemical and thermic insults arising in various methods of cavity filling . It was our wish to investigate in the simplest possible manner the permeability for fluid of some phosphate cements which are used for the lining of cavities. This would be analoguos to an investigation as to how good these cements are as chemical isolators in lining cavities which are filled with silicate cements or selfbinding acrylics. The testing was carried out by simple experiments, i. e.: 1. On freshly extracted teeth lining of the prepared cavities was undertaken with phosphate cements of soft, moderately firm and firm consistency, trade mark Galenika , Harvard and Dental Fillings. The permeability of these cements was checked by absorption of the fluid stained with carbolfuchsin through the cement base in the dentin. 2. A certain quantity (about 2 drops) of blue ink was placed on the previously prepared blocks made of phosphate cements. The permeability of these materials was determ ined by means of the absorption of the blue ink into the very mass of the cements. These two experiments did not give identical rezults, exept for the moderately hard consistency of the » Racim « phosphate cement which in both cases was impermeable and no passage of Uained fluid took place. The » Harvard « phosphate cement proved equally good, that is very iittle passage of stained fluids (Figs. 5. a. and b .) was seen » Galenika\u27s « phosphate cement showed great permeability of stained fluids, especially in the second experiment.Further research in this direction, and investigations by other authors will eventually give more complete and more precise results concering the quality of these phosphate cements.Unterlagen sollen die Pulpa vor chemischen und thermischen Schadigungen bei Fullungen schutzen. Die Aufgabe dieser Arbeit ist es die Durchlassigkeit der Zemente, die fur Unterlagen bei Silikat- oder Kunststoffullungen verwendet werden, zu prufen.Es wurden folgende Untersuchungen durchge fuhrt: 1 ) An frisch extrahierten Zahnen wurden Unterlagen mit weich, halbhart und hartangemischten Zementen der Firmen GaIenika , Harvard und Dental - Fillings , gemacht. Die Durchlassigkeit dieser Zemente wurde durch Apsorption der mit Karbol-Fuchsin gefarbten Zementflussigkeit im Dentin beobachtet.2 ) Eine Anzahl von Wurfeln aus Phosphatzement wurde mit 2 Tropfen blauer Tinte versetzt.Durch Apsorption der Tinte in der Zementmasse wurde die Durchlassigkeit bestimmt. Nur das halbhart angemischte Phosphatzement » Racim « zeigte sich in beiden Experimenten als undurchlassig. Das phosphatzement »Harvard« warfur die gefarbte Flussigkeit schwach durchlassig.(A bb 5 a, b ) . Das Phosphatzement »GaIenika « war in beiden Versuchen stark durchlassig.Genauere Angaben sind weiteren Untersuchungen vorbehalten

Spectra of Modular and Small-World Matrices

We compute spectra of symmetric random matrices describing graphs with general modular structure and arbitrary inter- and intra-module degree distributions, subject only to the constraint of finite mean connectivities. We also evaluate spectra of a certain class of small-world matrices generated from random graphs by introducing short-cuts via additional random connectivity components. Both adjacency matrices and the associated graph Laplacians are investigated. For the Laplacians, we find Lifshitz type singular behaviour of the spectral density in a localised region of small $|\lambda|$ values. In the case of modular networks, we can identify contributions local densities of state from individual modules. For small-world networks, we find that the introduction of short cuts can lead to the creation of satellite bands outside the central band of extended states, exhibiting only localised states in the band-gaps. Results for the ensemble in the thermodynamic limit are in excellent agreement with those obtained via a cavity approach for large finite single instances, and with direct diagonalisation results.Comment: 18 pages, 5 figure

Classical and Quantum Cosmology of Multigravity

Recently, a multigraviton theory on a simple closed circuit graph corresponding to the discretization of $S^1$ compactification of the Kaluza-Klein (KK) theory has been considered. In the present paper, we extend this theory to that on a general graph and study what modes of particles are included. Furthermore, we generalize it in a possible nonlinear theory based on the vierbein formalism and study classical and quantum cosmological solutions in the theory. We found that scale factors in a solution for this theory repeat acceleration and deceleration.Comment: 17 pages, 15 figures, RevTeX4.1, revised versio

Hidrolati - nusproizvodi prilikom destilacije etarskih ulja - hemijski sastav, biološka aktivnost i mogućnosti upotrebe

Hydrolates, also referred to as hydrosols, floral or distillate waters, as well as aromatic waters, are produced in the same isolation process with essential oils by steam distillation. A small amount of essential oil constituents is dissolved in hydrolates providing specific organoleptic properties and flavor, as well as biological activity which makes them useful as raw material in many industries. Their popularity is still on the rise, especially in aromatherapy. The objective in this review is to analyze the chemical compositions of hydrolates and their corresponding essential oils, as well as biological activity of hydrolates (antimicrobial, antioxidant and antiinflamatory) and potential uses, not only in food industry for flavoring, and preservation of fresh-cut fruits and vegetables, but also as functional (soft) drinks. However, hydrolates can be used in aromatherapy and cosmetics, as well as in organic agriculture and aquaculture.Hidrolati, koji se takođe nazivaju i hidrosoli, cvetne ili aromatične vode, kao i destilati, proizvode se u procesu destilacije etarskih ulja vodenom parom. Mala količina etarskog ulja nalazi se rastvorena u hidrolatima dajući im specifične organoleptičke osobine i ukus, kao i biološku aktivnost, što ih čini korisnim kao sirovinu u mnogim industrijama. Njihova popularnost poslednjih godina raste, posebno u aromaterapiji. Cilj ovog preglednog rada je da se analizira hemijski sastav hidrolata i njihovih etarskih ulja, kao i biološku aktivnost hidrolata (antimikrobna, antioksidativna i antiinflamatorna), ali i mogućnosti upotrebe, ne samo u prehrambenoj industriji kao prirodnih aroma i konzervanasa sveže isečenog voća i povrća, ali i funkcionalnih (bezalkoholnih) napitaka. Takođe, hidrolat i mogu da se koriste u aromaterapiji i kozmetici kao i u organskoj poljoprivredi i ribarstvu

Antioxidant and Antibacterial Activity of the Beverage Obtained by Fermentation of Sweetened Lemon Balm (Melissa offi cinalis L.) Tea with Symbiotic Consortium of Bacteria and Yeasts

Kombucha je napitak koji se tradicionalno dobiva fermentacijom zaslađenog crnog ili zelenog čaja (Camellia sinensis L.) s pomoću simbiotičke kulture bakterija i kvasaca (engl. SCOBY). U ovom je radu za pripremu napitka kombucha kao izvor dušika pri fermentaciji upotrijebljena melisa (Melissa officinalis L.). Tijekom sedmodnevne fermentacije mjereni su sljedeći parametri: pH-vrijednost, titracijska kiselost, udjeli ukupnih fenola i fenolnih spojeva, te sposobnost uklanjanja hidroksilnog (˙OH) i 1,1-difenil-2-pikrilhidrazilnog (DPPH) radikala da bi se utvrdila povezanost trajanja fermentacije s antioksidativnom i antibakterijskom aktivnošću fermentiranog napitka od melise. Određena je optimalna titracijska kiselost od 4 do 4,5 g/L, koju su potvrdili dugogodišnji konzumenti tog napitka. Ispitan je antibakterijski učinak napitaka povećane kiselosti od 8,12 g/L na jedanaest divljih bakterijskih sojeva. Rezultati pokazuju da se u proizvodnji fermentiranog napitka kombucha čaj (C. sinensis) može uspješno zamijeniti melisom. Udjel ukupnih fenola i sposobnost uklanjanja DPPH radikala bili su veći u podlozi s melisom nego u tradicionalnom napitku kombucha. Za biološku je aktivnost napitka kombucha s melisom najvjerojatnije zaslužna ružmarinska kiselina, glavni fenolni spoj u napitku. Vrijednosti EC50 pokazuju da napitak kombucha ima veću antioksidativnu vrijednost od čajnih infuzija C. sinensis L. i M. officinalis L., čemu vjerojatno pridonose metaboliti simbiotičke kulture bakterija i kvasaca. Kombucha s melisom optimalne i povećane titracijske kiselosti imala je izraženi antibakterijski učinak, ponajprije zbog prisustva octene kiseline, ali i zbog drugih sastojaka čaja te prisustva metabolita simbiotičke kulture.Kombucha is a fermented tea beverage which is traditionally prepared by fermenting sweetened black or green tea (Camellia sinensis L.) with symbiotic consortium of bacteria and yeasts (SCOBY). In this study, lemon balm (Melissa offi cinalis L.) was used as the only nitrogen source for kombucha fermentation. During the seven-day fermentation process, pH value, titratable acidity (TA), total phenolic content, phenolic compounds, and antioxidant activity against hydroxyl (˙OH) and 1,1-diphenyl-2-picrylhydrazil (DPPH) radicals were measured to detect the connection between the fermentation time and antioxidant and antibacterial activities of lemon balm kombucha. Antibacterial activity of fi nished beverages with optimum acidity (TA=4–4.5 g/L), the value which is confi rmed by long-time kombucha consumers, and enhanced acidity (TA=8.12 g/L) was tested against eleven wild bacterial strains. The results showed that lemon balm could be successfully used as an alternative to C. sinensis L. for kombucha fermentation. Total phenolic content and antioxidant activity against DPPH radicals of lemon balm fermentation broth were higher than those of traditional kombucha. Rosmarinic acid is the main phenolic compound of the lemon balm-based kombucha that probably provides biological activity of the beverage. Judging from the EC50 values, kombucha beverages exhibited higher antioxidant activities compared with C. sinensis L. and M. offi cinalis L. infusions, which can probably be ascribed to SCOBY metabolites. Lemon balm kombucha with both optimum and enhanced acidity showed antibacterial activity, which can be primarily ascribed to acetic acid, but also to some other tea components and SCOBY metabolites