974 research outputs found

    Management of erectile dysfunction post-radical prostatectomy

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    © 2015 Saleh et al.Radical prostatectomy is a commonly performed procedure for the treatment of localized prostate cancer. One of the long-term complications is erectile dysfunction. There is little consensus on the optimal management; however, it is agreed that treatment must be prompt to prevent fibrosis and increase oxygenation of penile tissue. It is vital that patient expectations are discussed, a realistic time frame of treatment provided, and treatment started as close to the prostatectomy as possible. Current treatment regimens rely on phosphodiesterase 5 inhibitors as a first-line therapy, with vacuum erection devices and intraurethral suppositories of alprostadil as possible treatment combination options. With nonresponders to these therapies, intracavernosal injections are resorted to. As a final measure, patients undergo the highly invasive penile prosthesis implantation. There is no uniform, objective treatment program for erectile dysfunction post-radical prostatectomy. Management plans are based on poorly conducted and often underpowered studies in combination with physician and patient preferences. They involve the aforementioned drugs and treatment methods in different sequences and doses. Prospective treatments include dietary supplements and gene therapy, which have shown promise with there proposed mechanisms of improving erectile function but are yet to be applied successfully in human patients

    Cuscuton: A Causal Field Theory with an Infinite Speed of Sound

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    We introduce a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a scalar field theory with a non-canonical kinetic term (or k-essence). Even though perturbations of Cuscuton propagate superluminally, we show that they have a locally degenerate phase space volume (or zero entropy), implying that they cannot carry any microscopic information, and thus the theory is causal. Even coupling to ordinary scalar fields cannot lead to superluminal signal propagation. Furthermore, we show that the family of constant field hypersurfaces are the family of Constant Mean Curvature (CMC) hypersurfaces, which are the analogs of soap films (or soap bubbles) in a Euclidian space. This enables us to find the most general solution in 1+1 dimensions, whose properties motivate conjectures for global degeneracy of the phase space in higher dimensions. Finally, we show that the Cuscuton action can model the continuum limit of the evolution of a field with discrete degrees of freedom and argue why it is protected against quantum corrections at low energies. While this paper mainly focuses on interesting features of Cuscuton in a Minkowski spacetime, a companion paper (astro-ph/0702002) examines cosmology with Cuscuton dark energy.Comment: 11 pages, 1 figure, added discussion of "coupled cuscuton", matches the published version in PR

    Ab initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au19_{19} and Au20_{20} Clusters

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    Density functional molecular dynamics simulations have been carried out to understand the finite temperature behavior of Au19_{19} and Au20_{20} clusters. Au20_{20} has been reported to be a unique molecule having tetrahedral geometry, a large HOMO-LUMO energy gap and an atomic packing similar to that of the bulk gold (J. Li et al., Science, {\bf 299} 864, 2003). Our results show that the geometry of Au19_{19} is exactly identical to that of Au20_{20} with one missing corner atom (called as vacancy). Surprisingly, our calculated heat capacities for this nearly identical pair of gold cluster exhibit dramatic differences. Au20_{20} undergoes a clear and distinct solid like to liquid like transition with a sharp peak in the heat capacity curve around 770 K. On the other hand, Au19_{19} has a broad and flat heat capacity curve with continuous melting transition. This continuous melting transition turns out to be a consequence of a process involving series of atomic rearrangements along the surface to fill in the missing corner atom. This results in a restricted diffusive motion of atoms along the surface of Au19_{19} between 650 K to 900 K during which the shape of the ground state geometry is retained. In contrast, the tetrahedral structure of Au20_{20} is destroyed around 800 K, and the cluster is clearly in a liquid like state above 1000 K. Thus, this work clearly demonstrates that (i) the gold clusters exhibit size sensitive variations in the heat capacity curves and (ii) the broad and continuous melting transition in a cluster, a feature which has so far been attributed to the disorder or absence of symmetry in the system, can also be a consequence of a defect (absence of a cap atom) in the structure.Comment: 7 figure

    GaAs-based Self-Aligned Stripe Superluminescent Diodes Processed Normal to the Cleaved Facet

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    We demonstrate GaAs-based superluminescent diodes (SLDs) incorporating a window-like back facet in a self-aligned stripe. SLDs are realised with low spectral modulation depth (SMD) at high power spectral density, without application of anti-reflection coatings. Such application of a window-like facet reduces effective facet reflectivity in a broadband manner. We demonstrate 30mW output power in a narrow bandwidth with only 5% SMD, outline the design criteria for high power and low SMD, and describe the deviation from a linear dependence of SMD on output power as a result of Joule heating in SLDs under continuous wave current injection. Furthermore, SLDs processed normal to the facet demonstrate output powers as high as 20mW, offering improvements in beam quality, ease of packaging and use of real estate. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

    Permanent Draft Genome Sequence of Photorhabdus temperata Strain Hm, an Entomopathogenic Bacterium Isolated from Nematodes

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    Photorhabdus temperata strain Hm is an entomopathogenic bacterium that forms a symbiotic association with Heterorhabditis nematodes. Here, we report a 5.0-Mbp draft genome sequence for P. temperata strain Hm with a G+C content of 44.1% and containing 4,226 candidate protein-encoding genes

    Lymphotoxins and cytomegalovirus cooperatively induce interferon-beta, establishing host-virus détente

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    Tumor necrosis factor (TNF)-related cytokines regulate cell death and survival and provide strong selective pressures for viruses, such as cytomegalovirus (CMV), to evolve counterstrategies in order to persist in immune-competent hosts. Signaling by the lymphotoxin (LT)-β receptor or TNF receptor-1, but not Fas or TRAIL receptors, inhibits the cytopathicity and replication of human CMV by a nonapoptotic, reversible process that requires nuclear factor κB (NF-κB)-dependent induction of interferon-β (IFN-β). Efficient induction of IFN-β requires virus infection and LT signaling, demonstrating the need for both host and viral factors in the curtailment of viral replication without cellular elimination. LTα-deficient mice and LTβR-Fc transgenic mice were profoundly susceptible to murine CMV infection. Together, these results reveal an essential and conserved role for LTs in establishing host defense to CMV

    Draft Genome Sequence of Photorhabdus luminescens subsp. laumondii HP88, an Entomopathogenic Bacterium Isolated from Nematodes

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    Photorhabdus luminescens subsp. laumondii HP88 is an entomopathogenic bacterium that forms a symbiotic association with Heterorhabditis nematodes. We report here a 5.27-Mbp draft genome sequence for P. luminescens subsp. laumondii HP88, with a G+C content of 42.4% and containing 4,243 candidate protein-coding genes

    Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance

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    Chalki basalts as a small body of volcanic rocks have green to grayish green color due to their nearly complete alteration to chlorite. The essential minerals of Chalki basalt to andesitic basalts are plagioclase (labradorite, An51–61; andesine, An35 to An42; and oligoclase, An22). Moreover, there is sodic plagioclase (albite, An0.1 to An04) whose coexistence with the other more calcic plagioclase means that albitization had occurred. The other essential mineral is pyroxene (endiopside, en66–68 wo27–28 fs05–06; and subcalcic augite, en72 wo14 fs14). Olivine (Fo80–81) is also present. According to the NiO content (0.11–0.12 wt%) in olivine grains, they are interpreted to be originated tectonically. The prevalent chlorite in all the samples is mainly diabantite and penninite, indicating chloritization after the ferromagnesian olivine and pyroxene. Serpentine (type lizardite and chrysotile) is also recorded as lesser alteration product after the forsteritic olivine. Rare secondary hornblende (type magnesiohornblende) is also found. The spinel group as accessory minerals is defined as magnetite, chromian magnetite, and chromian spinel giving the imprints of their metamorphic origin due to low temperature sub-sea metamorphism and also of alpine type
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