On Wheeler's delayed-choice Gedankenexperiment and its laboratory realization

Here, we present an analysis and interpretation of the experiment performed by Jacques et al. (2007 Science 315, 966), which represents a realization of Wheeler's delayed-choice Gedankenexperiment. Our analysis is based on the evolution of the photon state, since the photon enters into the Mach-Zehnder interferometer with a removable beam-splitter until it exits. Given the same incident photon state onto the output beam-splitter, BS_output, the photon's state at the exit will be very different depending on whether BS_output is on or off. Hence, the statistics of photon counts collected by the two detectors, positioned along orthogonal directions at the exit of the interferometer, is also going to be very different in either case. Therefore, it is not that the choice of inserting (on) or removing (off) a beam-splitter leads to a delayed influence on the photon behavior before arriving at the beam-splitter, but that such a choice influences the photon state at and after BS_output, i.e., after it has exited from the Mach-Zehnder interferometer. The random on/off choice at BS_output has no delayed effect on the photon to behave as a wave or a corpuscle at the entrance and inside the interferometer, but influences the subsequent evolution of the photon state incident onto BS_output.Comment: 7 pages, 4 figure

Coherence loss and revivals in atomic interferometry: A quantum-recoil analysis

The coherence effects induced by external photons coupled to matter waves inside a Mach-Zehnder three-grating interferometer are analyzed. Alternatively to atom-photon entanglement scenarios, the model considered here only relies on the atomic wave function and the momentum shift induced in it by the photon scattering events. A functional dependence is thus found between the observables, namely the fringe visibility and the phase shift, and the transversal momentum transfer distribution. A good quantitative agreement is found when comparing the results obtained from our model with the experimental data.Comment: 18 pages, 4 figure

Trajectory-based interpretation of laser light diffraction by a sharp edge

In the diffraction pattern produced by a half-plane sharp edge when it obstructs the passage of a laser beam, two characteristic regions are noticeable. There is a central region, where it can be noticed the diffraction of laser light in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. On both sides of the edge, there are also very long light traces along the normal to the edge of the obstacle. The theoretical explanation to this phenomenon is based on the Fresnel-Kirchhoff diffraction theory applied to the Gaussian beam propagation behind the obstacle. Here we have supplemented this explanation by considering electromagnetic flow lines, which provide a more complete interpretation of the phenomenon in terms of electric and magnetic fields and flux lines, and that can be related, at the same time, with average photon paths.Comment: 13 pages, 5 figure

Neurocognitive mechanisms for processing inflectional and derivational complexity in English

In the current paper we discuss the mechanisms that underlie the processing of inflectional and derivational complexity in English. We address this issue from a neurocognitive perspective and present evidence from a new fMRI study that the two types of morphological complexity engage the language processing network in different ways. The processing of inflectional complexity selectively activates a left-lateralised frontotemporal system, specialised for combinatorial grammatical computations, while derivational complexity primarily engages a distributed bilateral system, argued to support whole-word, stem based lexical access. We discuss the implications of our findings for theories of the processing and representation of morphologically complex words

Radiographic and Prosthetic Assessment Prior to Implantoprosthetic Therapy

Jedan od osnovnih uvjeta uspješnosti terapije oseointegrirajućim usadcima jest dobro predkirurško planiranje. Svrha je ovoga rada prikazati na slučaju djelomične bezubosti u distalnom dijelu mandibule mogućnosti radiološke i protetske ocjene prije kirurškoga tretmana. Na modelu čeljusti učinjeno je dijagnostičko navoštavanje. Nakon toga izrađena je šablona iz vakuum termoplastične folije. Metalne kuglice poznatoga promjera stavljene su u pozicije navoštanih zuba kako bi se radiološkom tehnikom ocijenila mogućnost implantacije u predviđenim pozicijama. Učinjen je klasični ortopantomogram te na temelju njega i slojeviti tomogram s točnim presjecima mandibule na položajima budućih usadaka. Na temelju rendgenskih nalaza određen je položaj i duljina usadaka. Prikazan je klasičan dvofazni kirurški protokol te operacijska tehnika s intraoralnim pretprotetskim šablonama. Uporabljeni su usadci Astratech microthread koničnoga profila kako bi se promjerom usatka što više približili promjeru budućega zuba. Dužina usatka određena je u skladu s navedenom radiološkom raščlambom tako da je usadak na poziciji 35 kraći od usadaka 34 i 37 zbog anatomske pozicije foramena mentale. Pri kirurškome pozicioniranju usatka osim pozicije koja je određena šablonom usadci su u okomitome smjeru pozicionirani u skladu s biološkom širinom sluznice i u konačnici parodontološko estetskim zahtjevima. Rezultati prikazuju uspješnost terapije nakon dobra planiranja i pripreme. Prikazana je prednost slojevite tomografije u planiranju i određivanju anatomsko-morfoloških karakteristika donje čeljusti koja nam daje sigurnost u izboru dužine, a osobito širine usatka. Predkirurško planiranje je postupak kojime možemo predvidjeti položaj usatka i estetiku budućega protetskog rada te tako olakšati kirurški zahvat.One of the fundamental pre-conditions for successful therapy by osseo-integrating implants is good pre-surgical planning. The aim of this work is to present the possibilities of radiographic and prosthetic evaluation prior to surgical treatment in the case of partial edentulousness.in the distal part of the mandibula. Diagnostic wax-up is done on a model of the jaw. After which a pattern is made of vacuum thermoplastic foil. Metal pellets of known diameter are placed in the positions of the waxed-up teeth to enable radiographic evaluation of the possibility of implantation in the planned positions. Classical orthopantomography is performed on the basis of which a multi-layer tomogram is done with exact cross-sections of the mandibula in the positions of future implants. On the basis of radiographic findings the position and length of the implants are determined. The classical two-phase surgical protocol is described and surgical technique with intraoral pre-prosthetic patterns. Astratech microthread implants of conical profile are used to ensure that the implant diameter is as close as possible to the diameter of the future tooth. The length of an implant is determined in accordance with the cited radiographic analysis, so that the implant in position 35 is shorter in relation to implants 34 and 37, due to the anatomic position of the foramen mentale. During surgical positioning of implants, apart from the position which is defined by the pattern, in the vertical direction the implants are positioned in accordance with the biological width of the mucous membrane and finally with periodontal aesthetic requirements. The results show the success of the therapy following good planning and preparation. The advantage is shown of multi-layer tomography in planning and determining the anatomical-morphological characteristics of the lower jaw, which provides assurance in the choice of length and particularly the width of the implant. Pre-surgical planning is a procedure by which it is possible to foresee the position of an implant and aesthetics of future prosthetic work, and thus to facilitate the surgical intervention

Therapy of Advanced Periimplantitis - Case Presentation Clinical and Microbial Results after 10 Months

Sve više bude postavljenih usadaka neizbježno je da će biti više komplikacija u vezi s takvim terapijskim postupkom. Jedna od komplikacija koju je najteže izliječiti i koja posljedično može dovesti do gubitka usatka jest bakterijski uzrokovan periimplantitis. U ovome prikazu slučaja opisat će se uspješna terapija uznapredovala periimplantitisa. Pacijent u dobi od 58 godina poslan je parodontologu zbog smetnji u usnoj šupljini u obliku neugodna zadaha te gnojenja oko zuba i usadaka. Prigodom parodontološkoga pregleda opaženo je da su oba usatka na mjestima 22 i 25 zahvaćena periimplantatnim mukozitisom te da postoji krvarenje i gnojenje pri sondiranju. Kod usatka u području 25 postojao je i problem potpunoga nedostatka keratinizirane gingive. Na temelju kliničkog i rtg nalaza te pozitivnog mikrobiološog nalaza na parodontopatogene dijagnosticiran je periimplatitis oko oba usatka. Inicijalna parodontološka terapija završena je u četiri posjeta. Pacijent je dobio upute kako da održava oralnu higijenu te je uključena antiseptička terapija, ispiranje klorheksidinom i uporaba klorheksidinskoga gela izravno u džepove oko usadaka. Kako i nakon takve terapije gnojenje nije prestalo, uključena je i antibiotska terapija te ispiranje džepova jodom. Nakon što je infektivni proces uspješno stavljen pod nadzor, u daljnjem terapijskom postupku proveden je parodontološki kirurški zahvat kako bi se oko usatka 25 pokušao ispraviti nedostatak keratinizirane gingive i dobiti nov pričvrstak. Pošto je režanj odignut, površina usatka očišćena je sterilnom vatom natopljenom u klorheksidin, a s nepca je uzet vezivni presadak te je postavljen na kosti i na izložene navoje usatka. Preko presatka postavljen je Gengigel (hijaluronska kiselina) radi boljeg cijeljenja rane. Pet mjeseci nakon operacije ponovljena je mikrobiološka raščlamba te više nije bilo parodontnih patogena, a klinička mjerenja su pokazala da je smanjena dubina sondiranja, da ne postoji krvarenje ili gnojenje i da je nastala zona keratinizirane gingive od 2 mm oko usatka 25.With the ever increasing number of placed implants it is inevitable that the number of complications connected with such therapeutic procedure will also increase. One of the complications which is hardest to treat and which consequently can lead to loss of the implant, is bacterial caused periimplantitis. This case presentation describes the successful therapy of advanced periimplantitis. The male patient, aged 58 years, was referred to the periodontist because of problems in the oral cavity in the form of unpleasant breath and suppuration around the tooth and implant. During the periodontal examination it was observed that both implants on places 22 and 25 were affected by periimplantic mucositis and bleeding and suppuration occurred during probing. With regard to the implant in area 25 the problem of complete loss of keratinised gingiva was also present. On the basis of the clinical and X-ray findings, and positive microbial test for periodontopathogens, periimplantitis was diagnosed around both implants. Initial periodontological therapy was carried out in four visits. The patient received instructions on the maintenance of oral hygiene and antiseptic therapy was included, rinsing with chlorhexidine and application of chlorhexidine gel directly into the pockets around the implants. As after this therapy the suppuration did not stop antibiotic therapy was included, with rinsing of the pockets with iodine. After successful control of the infective process, further therapy involved a periodontological surgical operation in order to correct the loss of keratinised gingiva around implant 25 and to obtain new attachment. After lifting the flap the surface of the implant was cleaned with sterile cotton wool soaked in chlorhexidine, and from the palate a connective transplant was taken and placed on the bone and the exposed thread of the implant. Gengigel (hyaluronic acid) was placed over the transplant for better healing of the wound. Five months after the operation microbial analysis was repeated. Periodontal pathogens were no longer present and clinical measurements showed reduced probing depth, absence of bleeding and suppuration, and the occurrence of zones of keratinised gingiva of 2 mm around implant 25

The influence of powder particle size on properties of Cu-Al2O3 composites

Inert gas atomized prealloyed copper powder containing 2 wt.% Al (average particle size ≈ 30 μm) and a mixture consisting of copper (average particle sizes ≈ 15 μm and 30 μm) and 4 wt.% of commercial Al2O3 powder particles (average particle size ≈ 0.75 μm) were milled separately in a high-energy planetary ball mill up to 20 h in air. Milling was performed in order to strengthen the copper matrix by grain size refinement and Al2O3 particles. Milling in air of prealloyed copper powder promoted formation of finely dispersed nano-sized Al2O3 particles by internal oxidation. On the other side, composite powders with commercial micro-sized Al2O3 particles were obtained by mechanical alloying. Following milling, powders were treated in hydrogen at 400 0C for 1h in order to eliminate copper oxides formed on their surface during milling. Hot-pressing (800 0C for 3 h in argon at pressure of 35 MPa) was used for compaction of milled powders. Hot-pressed composite compacts processed from 5 and 20 h milled powders were additionally subjected to high temperature exposure (800°C for 1 and 5h in argon) in order to examine their thermal stability. The results were discussed in terms of the effects of different size of starting powders, the grain size refinement and different size of Al2O3 particles on strengthening, thermal stability and electrical conductivity of copper-based composites

Coherence loss and revivals in atomic interferometry: A quantum-recoil analysis

The coherence effects induced by external photons coupled to matter waves inside a MachZehnder three-grating interferometer are analyzed. Alternatively to atomphoton entanglement scenarios, the model considered here only relies on the atomic wavefunction and the momentum shift induced in it by the photon scattering events. A functional dependence is thus found between the observables, namely the fringe visibility and the phase shift, and the transversal momentum transfer distribution. Good quantitative agreement is found when comparing the results obtained from our model with the experimental data. © 2012 IOP Publishing Ltd.MD, MB and DA acknowledge support from the Ministry of Science of Serbia under Projects OI171005, OI171028 and III45016. ASS acknowledges support from the Ministerio de Econom´ıa y Competitividad (Spain) under Projects FIS2010-22082 and FIS2010-29596-C02-01, as well as for a “Ram´on y Cajal” Research Fellowship.Peer Reviewe

Antimicrobial activity of chalcones and in vitro effect on physiological and biochemical characteristics and expression of virulence factors of methicillin - resistant Staphylococcus aureus

Uvod: Meticilin-rezistentan S. aureus (MRSA) je jedan od glavnih izazivača intrahospitalnih infekcija sa čestim letalnim ishodom i infekcija kod mladih i zdravih ljudi koji dolaze iz vanbolničke sredine. Brz razvoj rezistencije stafilokoka na nove antimikrobne agense i interhumano širenje rezistentnih sojeva su glavni terapijski problemi današnjice. Iz tog razloga je neophodno razviti nove agense koji bi imali primenu u prevenciji ili lečenju stafilokoknih infekcija. Halkoni spadaju u grupu flavonoida, jedinjenja koja se mogu izolovati iz prirodnih izvora kao što su biljke, voće i povrće ili se dobiti metodama klasične i kombinatorne sinteze. Hemijska struktura halkona se sastoji od dva aril prstena koja su povezana α,β-nezasićenim ketonom. Dosadašnja istraživanja su pokazala da različiti halkoni ispoljavaju širok spektar bioloških aktivnosti, kao što su antibakterijska, antivirusna, antigljivična, antiangiogena, antitumorska, antiproliferativna i antiinflamatorna aktivnost. Ciljevi istraživanja: Osnovni cilj istraživanja je bilo ispitivanje osetljivosti genotipski i fenotipski heterogenih MRSA sojeva na tri sintetisana halkona: Bis-(2-hydroxyphenyl)- propenona (u daljem tekstu O-OH), 3-(3-Hydroxy-phenyl)-1-(2-hydroxyphenyl)- propenona (u daljem tekstu M-OH) i 3-(4-Hydroxy-phenyl)-1-(2-hydroxyphenyl)- propenona (u daljem tekstu P-OH) i ispitivanje in vitro uticaja halkona na biohemijsko-fiziološke osobine MRSA sojeva, ekspresiju faktora virulencije (produkciju glikokaliksa, produkciju biofilma i vezivanje za humani fibronektin) i produkciju stafilokoknih hemolizina. Takoñe je izvršeno i ispitivanje efekta kombinovane primene halkona i antibiotika sa različitim mehanizmima delovanja na rast izolovanih MRSA sojeva. Materijal i metode: Izolovani sojevi S. aureus su identifikovani kao MRSA pomoću konvencionalnih metoda, komercijalnim automatizovanim sistemom (VITEK 2 ID karticama) i molekularnim metodama (PCR metod - detekcija nuc i mecA gena). Genotipizacija izolovanih MRSA sojeva je izvršena različitim PCR protokolima na osnovu čega su MRSA sojevi klasifikovani u različite SCCmec tipove, agr tipove, spa tipove i grupisani u spa klonske komplekse...Introduction: Staphylococcus aureus is potentially pathogenic bacterium that causes a broad spectrum of diseases, ranging from minor infections of the skin and soft tissue in the community, to severe nosocomial infections like endocarditis, bacteremia and sepsis. Multiresistance of methicillin-resistant S.aureus (MRSA) is one of the most serious therapeutical problems nowadays, and requires urgent development of new antibacterial compounds. Chalcones belong to a group of naturally occurring flavonoids with chemical structure made of two aryl rings linked by a α,β-unsaturated ketone. Although these compounds are usually isolated from various plant species, they can also be obtained by the methods of classical and combinatorial synthesis. Chalcones are compounds with potent biological activities, amongst which are antibacterial, antiviral, antifungal, antiproliferative and antiinflammatory. The aim of the study: The goal of this study was to evaluate the antibacterial effect of three newly-synthesized chalcones: 1,3- Bis-(2-hydroxy-phenyl)-propenone (further referred as O-OH), 3-(3-hydroxy-phenyl)-1-(2-hydroxy-phenyl)-propenone (further referred as M-OH) and 3-(4-hydroxy-phenyl)-1-(2-hydroxy-phenyl)-propenone (further referred as P-OH) against genetically diverse clinical isolates of MRSA, and the effect on physiological and biochemical characteristics and expression of virulence factors (production of glycocalyx, biofilm and adherence to human fibronectin) and production of α-hemolysin of these bacteria. One of the aims of this study was also to investigate the synergism of chalcones with various β-lactam and non- β-lactam antibiotics. Methods: Clinical isolates of S. aureus were identified as MRSA with classical methods, commercial automated microbiological identification system (VITEK 2 ID test cards) and molecular methods (PCR method for detection of nuc and mecA gene). Genotyping of MRSA was performed with adequate PCR protocols for the detection of SCCmec type, agr type, Panton-Valentin leucocidin (PVL) gene and spa type. Different spa types were clustered into spa clonal complexes (CC)..

Antiinflammatory and antioxidative properties of benfotiamine in activated microglial mouse cell line: role of proinflammatory signaling pathways

Inflamacija je zajedničko obeležje različitih patologija centralnog nervnog sistema (CNS), od traumatskih povreda i ishemije, preko neurodegenerativnih oboljenja, do psihijatrijskih poremećaja. Mikroglijske ćelije su rezidentne imunske ćelije CNS-a koje predstavljaju glavne pokretače i učesnike u inflamaciji. Mikroglija se aktivira u odgovoru na promene u homeostazi CNS-a pri čemu menja svoje morfološke i funkcionalne karakteristike. U aktiviranoj mikrogliji dolazi do reorganizacije citoskeleta što omogućava uvećanje ćelijskog tela, fagocitozu patogena ili ćelijskog otpada, kao i migraciju do mesta infekcije ili povrede. Takođe, aktivirana mikroglija produkuje brojne proinflamatorne medijatore, kao što su proinflamatorni citokini, hemokini, proteaze, reaktivne kiseonične i azotne vrste. Iako ovi molekuli imaju važnu ulogu u odbrani CNS-a od patogena i drugih štetnih stimulusa, oni tokom hronične aktivacije mikroglije dovode do snažnog inflamatornog odgovora, oštećuju i zdrave ćelije i dovode do neurodegeneracije. Stoga je smanjenje prekomerne mikroglijske aktivacije jedna od glavnih strategija u terapiji oboljenja CNS-a koja se odlikuju inflamacijom. Benfotiamin (S-benzoiltiamin O-monofosfat) je analog vitamina B1 sa većom biološkom raspoloživošću i dobrim farmakološkim profilom. Benfotiamin pokazuje povoljne efekte u lečenju neuropatija, nefropatija i retinopatija izazvanih dijabetesom. Pored toga, pokazana su antiinflamatorna i antioksidativna svojstva benfotiamina, ali njegov efekat na aktiviranu mikrogliju do sada nije poznat. Stoga, cilj ove disertacije bio je da se ispita potencijal benfotiamina da smanji aktivaciju mikroglije u in vitro modelu neuroinflamacije. Eksperimenti su rađeni na BV-2 mikroglijskoj ćelijskoj liniji koja je bila stimulisana lipopolisaharidom (LPS), što predstavlja dobro okarakterisan in vitro model aktivacije mikroglije. Rezultati dobijeni u ovoj disertaciji pokazuju da benfotiamin sprečava morfološke promene izazvane stimulacijom BV-2 ćelija LPS-om..