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Proteome Profiling of Breast Tumors by Gel Electrophoresis and Nanoscale Electrospray Ionization Mass Spectrometry

We have conducted proteome-wide analysis of fresh surgery specimens derived from breast cancer patients, using an approach that integrates size-based intact protein fractionation, nanoscale liquid separation of peptides, electrospray ion trap mass spectrometry, and bioinformatics. Through this approach, we have acquired a large amount of peptide fragmentation spectra from size-resolved fractions of the proteomes of several breast tumors, tissue peripheral to the tumor, and samples from patients undergoing noncancer surgery. Label-free quantitation was used to generate protein abundance maps for each proteome and perform comparative analyses. The mass spectrometry data revealed distinct qualitative and quantitative patterns distinguishing the tumors from healthy tissue as well as differences between metastatic and non-metastatic human breast cancers including many established and potential novel candidate protein biomarkers. Selected proteins were evaluated by Western blotting using tumors grouped according to histological grade, size, and receptor expression but differing in nodal status. Immunohistochemical analysis of a wide panel of breast tumors was conducted to assess expression in different types of breast cancers and the cellular distribution of the candidate proteins. These experiments provided further insights and an independent validation of the data obtained by mass spectrometry and revealed the potential of this approach for establishing multimodal markers for early metastasis, therapy outcomes, prognosis, and diagnosis in the future. © 2008 American Chemical Society

Transport and Spectral Properties of Electrons on Curved Three-Dimensional Topological Insulators

Over the last two decades, topological insulators have attracted considerable interest due to their unique ability to robustly conduct charge carriers at their surfaces, while remaining insulating inside. To date, the mechanism by which these surface states arise has been well understood, giving us considerable insight into the massless Dirac particle nature of these states. However, previous studies have focused only on trivial geometries of topological insulators, such as flat slabs or thin films, with no intrinsic or extrinsic curvature. Moreover, experimental progress shows the possibility of growing topological insulating crystalline structures with various complex geometries. Therefore, to fill the theoretical gap and to motivate new experiments, we generalize the description of topological insulators to general curved spaces, and consider the Dirac Hamiltonian on several prominent curved surfaces, such as the cone and the pseudosphere, subjected to a coaxial magnetic field. In the first part of the thesis, we calculate the bound states on these surfaces and find that the energies decompose into two branches, one which is curvature independent and always scales with B^{1/2}, and one which is curvature dependent, giving us, for example, in the case of the pseudosphere, a peculiar scaling of B^{1/4}. Notably, we find a further surface whose curvature dependent part of the spectrum has bound state energies that are independent of the magnetic field. In the second part of the thesis, we perform quantum magnetotransport simulations on the pseudosphere, including a longitudinal conductance and a 4-terminal quantum Hall simulation. For the longitudinal simulation, we reveal the mechanism by which electrons propagate along curved topological insulator surfaces, consisting of resonant tunneling through non-degenerate energy levels that have a non-zero overlap due to disorder effects in the materials, such as impurities. For the quantum Hall transport simulation, we reveal the mechanism by which the edge states give rise to quantum Hall plateaus in a 4 terminal measurement on curved surfaces

HARMONIC FREQUENCY COMB COVERING THE MID-INFRARED MOLECULAR FINGERPRINT REGION

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.25]{frequency_comb_28_02.eps} \end{wrapfigure} We present a multi-channel harmonic frequency comb covering the mid-infrared spectral range between 15 and 85 THz (or 3.5 - 20 $\mu$m, or 500 to 2860 cm$^{-1}$) with a record 1-mW$/$THz-level power spectral density. An Er-fiber-based oscillator is wavelength-shifted to a central wavelength of 1960 nm and a chirped-pulse Tm-fiber amplifier provides a 50-MHz-repetition-rate train of 250-fs pulses with 120 W of average power. Nonlinear self-compression in two fused-silica fibers results in two channels, yielding 11-fs pulses with 4.5 W (Channel 1) and 25-fs pulses with 25 W (Channel 2). Subsequent intrapulse difference-frequency generation (DFG) in 1-mm-thin GaSe crystals results in a coverage of the entire molecular fingerprint region with only two phase matching angles for each channel (see Figure). DFG inherently provides phase-stable pulses, leading to a harmonic frequency comb. The 120-W average power of the near-infrared frontend suffices for the parallel implementation of multiple channels, facilitating broadband spectroscopy

Findings of an experimental study in a rabbit model on posterior capsule opacification after implantation of hydrophobic acrylic and hydrophilic acrylic intraocular lenses

Nikolaos Trakos1, Elli Ioachim2, Elena Tsanou2, Miltiadis Aspiotis1, Konstantinos Psilas1, Chris Kalogeropoulos11University Eye Clinic of Ioannina, Ioannina, Greece; 2Pathology Department, University of Ioannina, Ioannina, GreecePurpose: Study on cell growth on the posterior capsule after implantation of hydrophobic acrylic (Acrysof SA 60 AT) and hydrophilic acrylic (Akreos Disc) intraocular lenses (IOL) in a rabbit model and comparison of posterior capsule opacification (PCO).Methods: Phacoemulsification was performed in 22 rabbit eyes, and two different IOL types (Acrysof SA60 AT and Akreos Disc) were implanted. These IOLs had the same optic geometry (square edged) but different material and design. Central PCO (CPCO), peripheral PCO (PPCO), Sommering’s ring (SR) formation, type of growth, extension of PCO, cell type, inhibition, and fibrosis were evaluated three weeks after surgery. Histological sections of each globe were prepared to document the evaluation of PCO.Results: No statistically significant difference was observed between a hydrophobic acrylic IOL and a hydrophilic acrylic IOL in relation to the CPCO, PPCO, type of growth, extension, cell type, inhibition, and fibrosis. Statistically significant difference was observed in relation to the formation of SR with Acrysof SA 60 AT group presenting more SR than Akreos Disc group.Conclusion: PCO was not influenced by the material of the IOL or the design of the haptics of the IOLs we studied.Keywords: posterior capsule opacification, intraocular lenses, rabbit mode