Cracking the Odor Code: Molecular and Cellular Deconstruction of the Olfactory Circuit of Drosophila Larvae

The Drosophila larva offers a powerful model system to investigate the general principles by which the olfactory system processes behaviorally relevant sensory stimuli. The numerically reduced larval olfactory system relieves the formidable molecular and cellular complexity found in other organisms. This thesis presents a study in four parts that investigates molecular and neuronal mechanisms of larval odor coding. First, the larval odorant receptor (OR) repertoire was characterized. ORs define the olfactory receptive range of an animal. Each of the 21 larval olfactory sensory neurons (OSNs) expresses one or rarely two ORs, along with the highly conserved olfactory co-receptor Or83b. Second, odor response profiles of 11 larval OSNs were characterized by calcium imaging. A subset of larval neurons showed overlapping responses to the set of odorants tested, while other neurons showed either very narrow or very broad tuning. Third, the olfactory circuit for ethyl butyrate was investigated in detail. Three OSNs, expressing Or35a, Or42a and Or42b, responded with different sensitivity to ethyl butyrate. Second order projection neurons synapsing with each of these OSNs showed similar concentration tuning, but inhibitory interneurons showed high response thresholds and were only activated at high odor concentrations. We correlated these concentration-dependent response properties with larval chemotaxis behavior. Fourth, the relevance of olfaction to animals was investigated in competitive rearing experiments. Or83b mutants experienced a selective disadvantage when they had to forage for limiting food sources, particularly when competing against larvae with normal olfactory function. Thus, odor coding is achieved both by peripheral tuning and central circuit modulation

Histopathological Change of Oral Malignant Tumour and Epithelial Dysplasia Subjected to Photodynamic Therapy

Objectives: The purpose of this study is to analyze the morphological change of cell nuclei and the change of proliferating activity of oral malignancy and epithelial dysplasia between before and after photodynamic therapy in order to predict recurrence.Material and Methods: We experienced 14 cases of oral squamous cell carcinoma, one case of verrucous carcinoma and seven cases of epithelial dysplasia treated by photodynamic therapy (PDT). The mean nuclear area (NA) and coefficient of variation of the nuclear area (NACV) of 100 nuclei per slide were calculated using computer-assisted image analysis in hematoxylin and eosin stained biopsy specimens before and after PDT. Additionally, proliferating cell nuclear antigen (PCNA) immunohistochemistry was carried out in each specimen.Results: The mean NA after PDT was significantly lower than that before PDT in the nonrecurrent group. However, there was no significant difference in mean NA before and after PDT in the recurrent group. There were no significance differences in NACV before and after PDT in either the nonrecurrent or recurrent group. Furthermore, the PCNA labelling indices of the specimens after PDT was significantly lower than that before PDT in both the nonrecurrent and the recurrent group.Conclusions: Mean nuclear area in the biopsy specimen after photodynamic therapy is likely to be a predictive marker for the recurrence of oral squamous cell carcinoma or epithelial dysplasia subjected to photodynamic therapy, while coefficient of variation of the nuclear area and proliferating cell nuclear antigen labelling indices are less helpful in predicting the recurrence of such lesions

Absolute elastic differential cross sections for electron scattering by C6H5CH3 and C6H5CF3 at 1.5–200 eV: a comparative experimental and theoretical study with C6H6

We present absolute differential cross sections DCS for elastic scattering from two benzene derivatives C6H5CH3 and C6H5CF3. The crossed-beam method was used in conjunction with the relative flow technique using helium as the reference gas to obtain absolute values. Measurements were carried out for scattering angles 15° –130° and impact energies 1.5–200 eV. DCS results for these two molecules were compared to those of C6H6 from our previous study. We found that 1 these three molecules have DCS with very similar magnitudes and shapes over the energy range 1.5–200 eV, although DCS for C6H5CF3 increase steeply toward lower scattering angles due to the dipole moment induced long-range interaction at 1.5 and 4.5 eV, and 2 that the molecular structure of the benzene ring significantly determines the collision dynamics. From the measured DCS, elastic integral cross sections have been calculated. Furthermore, by employing a corrected form of the independent-atom method known as the screen corrected additive rule, DCS calculations have been carried out without any empirical parameter fittings, i.e., in an ab initio nature. Results show that the calculated DCS are in excellent agreement with the experimental values at 50, 100, and 200 eV

Magneto-hydrodynamic Simulations of a Jet Drilling an HI Cloud: Shock Induced Formation of Molecular Clouds and Jet Breakup

The formation mechanism of the jet-aligned CO clouds found by NANTEN CO observations is studied by magnetohydrodynamical (MHD) simulations taking into account the cooling of the interstellar medium. Motivated by the association of the CO clouds with the enhancement of HI gas density, we carried out MHD simulations of the propagation of a supersonic jet injected into the dense HI gas. We found that the HI gas compressed by the bow shock ahead of the jet is cooled down by growth of the cooling instability triggered by the density enhancement. As a result, cold dense sheath is formed around the interface between the jet and the HI gas. The radial speed of the cold, dense gas in the sheath is a few km/s almost independent of the jet speed. Molecular clouds can be formed in this region. Since the dense sheath wrapping the jet reflects waves generated in the cocoon, the jet is strongly perturbed by the vortices of the warm gas in the cocoon, which breaks up the jet and forms a secondary shock in the HI-cavity drilled by the jet. The particle acceleration at the shock can be the origin of radio and X-ray filaments observed near the eastern edge of W50 nebula surrounding the galactic jet source SS433.Comment: 30 pages, 16 figure

Growth inhibition of HeLa cell by internalization of Mycobacterium bovis Bacillus Calmette-Guérin (BCG) Tokyo

<p>Abstract</p> <p>Background</p> <p>Intravesical BCG immunotherapy is effective for preventing recurrence and progression in none muscle-invasive bladder cancer but the dosing schedule and duration of treatment remain empirical. The mechanisms by which intravesical BCG treatment mediates antitumor activity are currently poorly understood.</p> <p>Results</p> <p>HeLa cell infected with <it>Mycobacterium bovis </it>Bacillus Calmette-Guérin(BCG) Tokyo which were different multiplicity of infection(MOI). Proliferation of HeLa cell reduced in a dose-dependent manner by live BCG. The cytoplasm of the HeLa cell showed variety lysosomal stages by internalized and interacted BCG.</p> <p>Conclusion</p> <p>Proliferated Live BCG secreted the protein and depressed the growth of tumor. The possibility for clinical introduction of BCG therapy for carcinoma reported with review of literature.</p

Processing and mechanical properties of hollow sphere aluminum foams

Hollow sphere metallic foams are a new class of cellular material that possesses the attractive advantages of uniform cell size distribution and regular cell shape. These result in more predictable physical and mechanical properties than those of cellular materials with a random cell size distribution and irregular cell shapes. In the present study, single aluminum hollow spheres with three kinds of sphere wall thickness as 0.1 mm, 0.3 mm and 0.5 mm were processed by a new pressing method. Hollow sphere aluminum foam samples were prepared by bonding together single hollow spheres with simple cubic packing (SC) and body-centered cubic packing (BCC). Compressive tests were carried out to evaluate the deformation behaviors and mechanical properties of the hollow sphere aluminum foams. Effects of the sphere wall thickness and packing style on the mechanical properties were investigated.<br /