Obrazowanie nadrozdzielcze za pomocą nanoukładów plazmonicznych

Niniejsza rozprawa dotyczy nanostruktur metaliczno-dielektrycznych, w których propagacja światła możliwa jest dzięki wzbudzeniom powierzchniowych plazmonów-polarytonów. W rozpatrywanych układach warstwowych możliwe jest uzyskanie obrazowania nadrozdzielczego. Praca poświęcona jest optymalizacji nadrozdzielczych struktur cienkowarstwowych, ich opisowi przy użyciu teorii ośrodków efektywnych, zastosowaniu teorii układów liniowych do ich projektowania, a także potencjalnym możliwościom ich wykorzystania. W pracy wykazano, że cienkowarstwowe metaliczno-dielektryczne struktury nadrozdzielcze zaprojektowane przy użyciu teorii ośrodków efektywnych są suboptymalne ze względu na uzyskiwaną rozdzielczość i współczynnik transmisji. Wykazano, że w drodze optymalizacji numerycznej możliwa jest poprawa obu tych wielkości, otrzymując ponadto struktury o grubszych warstwach, które z technologicznego punktu widzenia są łatwiejsze do wykonania. Straty propagacyjne dla struktury cienkowarstwowej przewidywane przez teorię ośrodków efektywnych mogą znacznie odbiegać od wyniku obliczonego ściśle, nawet gdy warstwy z których składa się struktura są kilkukrotnie cieńsze od długości fali. W szczególności, wykazano, że w strukturze o skończonej grubości warstw można uzyskać kilkukrotnie niższe straty niż w strukturze o podobnym składzie o infinitezymalnie cienkich warstwach. Ponadto wykazano, że cienkowarstwowe struktury nadrozdzielcze można łączyć w~nanoukłady optyczne pozwalające zmieniać przestrzenny rozkład natężenia wiązki świetlnej bez zaburzania rozkładu fazy pola. Zaproponowano użycie trzech połączonych ze sobą struktur cienkowarstwowych, do utworzenia struktury, która zmienia rozkład natężenia padającej wiązki gaussowskiej, ogniskując wiązkę w obszarze o podfalowych rozmiarach, oraz pozostawia przy tym niezaburzony, płaski kształt powierzchni stałej fazy.The subject of this thesis are metal-dielectric nano-structures, in which light propagation is possible thanks to the excitation of surface plasmon-polaritons. The layered structures considered in the thesis enable imaging with superresolution. The thesis is devoted to optimization of superresolving layered structures, their description with the use of the effective medium theory, the application of the theory of linear systems to their development, and to their potential applications. It has been demonstrated that thin layered metal-dielectric superresolving structures developed with use of the effective medium theory are suboptimal with respect to the attainable resolution and transmittance. It has been proven that these two characteristics can be improved simultaneously by means of numerical optimization, and the resultant structures consist of thicker layers, more feasible from the technological point of view. Propagation losses predicted by the effective medium theory for thin layered structures may differ significantly from the precise result, even in the case of structures with very thin layers - several-fold thinner than the free-space wavelength. In particular, a structure with a finite thickness of layers may show also several-fold smaller losses than a respective one with infinitesimally thin layers. It has also been demonstrated that superresolving layered structures can be combined into optical systems that allow for changing the spatial distribution of intensity of a propagating light beam, while its phase characteristics remains not aberrated. It has been proposed to combine three thin layered stacks to obtain a system capable of focusing the energy of an incident Gaussian beam into a subwavelength area, simultaneously preserving homogeneous and planar phase fronts

HIV infection and sex in sex-on-premises venues are associated with a higher risk of syphilis reinfection among men who have sex with men

Introduction: Recent outbreaks of syphilis occurred predominantly in men who have sex with men (MSM). A significant proportion of syphilis cases occur in MSM who had more than one episode of syphilis. This group may play an important role in syphilis transmission. Aim: To identify factors associated with the risk of syphilis reinfection. Material and methods: Forty-four MSM patients with the first episode of syphilis who were treated at the Department of Dermatology at the Jagiellonian University School of Medicine in Krakow, Poland were included in this study. After completing the treatment, the RPR testing was done every 3 months for 2 years in every patient. In the study period, we identified 12 (22%) cases of syphilis reinfection, eight of which were asymptomatic. Clinical, demographic and behavior data from patients with only one episode of syphilis were compared with those collected from repeaters. Results: Individuals with syphilis reinfection had concomitant HIV infection more frequently, reported a higher number of sexual partners and had sex in sex on premises venues more frequently (p < 0.05). In the multivariate analysis, we found that being HIV-infected MSM and having sex in sex on premises venues independently correlated with a higher risk of syphilis reinfection (OR = 9.6, 95% CI: 2.2-42.5 and OR = 5.6, 95% CI: 1.4-22.5, respectively). Conclusions: Results of our study highlight a strong need for frequent and repeated screening among MSM patients (especially those with concomitant HIV infection) with the first episode of syphilis and taking detailed patient’s history regarding also demographic and behavior data. We should also improve prevention policies to reduce risk behaviors in this population

Expression of metalloproteinases (MMP-2 and MMP-9) in basal-cell carcinoma

The aim of this study was to compare the expressions of mRNA for metalloproteinases (MMP-2 and MMP-9) and type IV collagen in two different histological types of basal-cell carcinoma (BCCs; nodular and infiltrative) and in normal tissues from the tumor interface. The study included biopsy specimens of the skin involved with BCC and normal skin adjacent the lesion. The expressions of mRNA for MMP-2, MMP-9 and type IV collagen were determined by means of RT-PCR (Reverse transcription polymerase chain reaction). The level of type IV collagen mRNA in nodular and infiltrative BCCs turned out to be significantly lower, and the expressions of MMP-2 and MMP-9 mRNA significantly higher than in normal tissues adjacent to these tumors. The expression of mRNA for MMP-9 but not for MMP-2 was significantly higher in infiltrative BCCs than in the nodular BCCs. In turn, normal tissues adjacent to nodular BCCs showed significantly higher levels of mRNA for MMP-2 and significantly lower levels of type IV collagen mRNA than the normal tissues from the interface of infiltrative BCCs. The findings suggest that MMP-2 and MMP-9 could be used as prognostic factors of BCCs