The inclination to higher ship speed is advancing in recent years. Among others, expectation is great from high speed vessels supporting short distance transportation of highly value added products. ...While the studies on supercavitating propeller and others having been made in late years, their study objects were limited mainly to propeller's propulsive performance. The root cavitation erosion, which is frequently sustained by high speed vessels, is the problem involved not only with deterioration of the propeller's durability or life but also with hindranceof the vessel's operational safety. Despite the fact that the study on its generation mechanism was made, and several countermeasures with some appendages against the phenomenon were devised, no development has been made yet on a method for an effective prevention of the phenomenon with any designing improvement applied to a propeller itself. If the root erosion generation peculiar to high speed vessels could be prevented, we understand that the relative method will surely comply with the need by the shipping industry. Under such a background as above, this study aims at development of the new propeller effective to prevention of root erosion. Our concept of the new blade section for the root erosion prevention is described in the concrete, to be followed by the description about verification of its effectiveness by means of model test and actual vessel test, and successful development of the new propeller with preventive effectiveness against the root erosion for high speed vessels.
Desert dust may be playing an active role in the climate system through its radiative forcing, and changes in the land surfaces due to climate change and human impacts may be modulating the dust ...source. However, these effects are not well understood. Two sets of studies investigate the interactions between North African desert dust and the climate. The first study addresses the question to what degree vegetation change and cultivation are contributing to the total dust source in North Africa. The dust distributions simulated with an off-line atmospheric transport model are converted to Total Ozone Mapping Spectrometer (TOMS) Absorbing Aerosol Indices (AAIs) using radiative transfer calculations, and compared with the actual satellite observations. The AAI gradients between Sahara (north) and Sahel (south) suggest that the optimal fraction of dust sources due to vegetation change and cultivation are 20-25%, while spatial and temporal correlations suggest 0-15% with the upper bound of 25-40%. However, sensitivity studies show that the uncertainties associated with meteorology and source parameterization used in the model may undermine the findings derived from the simulations. Such uncertainties need to be reduced in order to better constrain the roles of different types of dust sources using AAI simulation. The second study investigates the role of direct radiative forcing of dust in the Sahelian drought observed in the last three decades of 20 th century using simulations with an atmospheric general circulation model. Simulations forced by observed sea surface temperatures (SSTs) produce decrease of Sahel rainfall and increase of North African dust from 1950s to 1980s, consistent with the observations, but underestimate the magnitudes of observed changes. The effects of simulated changes in Atlantic and Indian Ocean SSTs, dust, vegetation, and greenhouse gas warming explain about 70% of the precipitation changes in Sahel between wet and dry periods. Dust accounts for about 20% and two thirds of this comes through cooling the troposphere over North Africa. The dust impact on Atlantic SST is of a secondary importance. Each of greenhouse gas warming of Indian Ocean and vegetation loss in Sahel accounts for about 25%. Processes excluded in the simulations such as land use impacts on dust, dynamic vegetation feedbacks, and indirect radiative effects, or errors in the model could be responsible for the remaining differences between observed and simulated precipitations.
Anti-cavitation erosion performances of thermally sprayed cobalt-based alloy coatings were compared with that of aluminum bronze castings, which have been utilized as s substrate for propeller in ...marine vessel because of its formability, endurance against seawater, and the cavitation erosion resistance. Cobalt-based alloy coatings are fabricated by using three thermal spray processes: atmospheric plasma spray, low-pressure plasma spray and high velocity oxygen fuel flame spray. The ultrasonic vibration type cavitation erosion testing apparatus were employed for the cavitation erosion rate measurement. The cavitation erosion performances determined by the specific volume loss rate of low-pressure plasma-sprayed cobalt-based alloy and HVOF sprayed cobalt-based alloy coatings were improved five times and twice compared with that of aluminum bronze castings, respectively. The anti-cavitation erosion performance of atmospheric plasma sprayed cobalt-based alloy coating did not reach the level of aluminum bronze castings.
A 42-year-old man presented with the chief complaint of dysuria which occurred suddenly. He showed a large quantity of post-voiding residue. Abdominal ultrasonography and cystoscope revealed a ...hypo-echoic mass with a diameter of 15 mm at the bladder neck. Transurethral resection of the cyst was performed, and dysuria was markedly improved. Pathological examination showed a retention cyst of the prostate.
We examined the immunopathology and the expression of human immunodeficiency virus type 1 (HIV-1) in lumbosacral dorsal root ganglia (DRGs) from 16 patients with acquired immunodeficiency syndrome ...(AIDS) and 10 HIV-1-seronegative controls. Using in situ hybridization, we detected HIV-1 RNA in a few perivascular cells in DRGs from five of 16 AIDS patients (31%). In addition, using polymerase chain reaction, we detected HIV-1 DNA more frequently in DRGs from four of five AIDS patients (80%) examined. We detected interleukin-6 (IL-6) immunoreactivity in endothelial cells in DRGs from seven of 16 AIDS patients (44%) but from none of 10 HIV-1-seronegative controls (0%). We found more nodules of Nageotte, CD8+ T lymphocytes, and intercellular adhesion molecule-1 (ICAM-1)-positive endothelial cells and mononuclear cells in DRGs from AIDS patients than in DRGs from controls. Increased numbers of nodules of Nageotte in DRGs of AIDS patients were associated with detection of HIV-1 RNA by in situ hybridization and detection of IL-6 by immunohistochemistry. We conclude that low levels of replication of HIV-1, through cytotoxic T lymphocytes or expression of cytokines, may play a role in the subclinical degeneration of sensory neurons frequently observed in DRGs of AIDS patients.
We examined the expression of Fas antigen and Bcl‐2 protein in thymic tissue surgically resected from 10 patients with myasthenia gravis, using immunocytochemical techniques. Histologically, thymic ...tissues from 7 myasthenia gravis patients showed hyperplasia, while 3 other patients had thymomas. In hyperplastic thymic tissue, immunoreactivity for Fas antigen was observed mainly in the network of medullary epithelial cells. In contrast, expression of Fas antigen was rare in the cortex. Fas antigen was also detected to some degree in thymoma tissue from 3 patients. Bcl‐2 protein was highly expressed in the medullary thymocytes in the hyperplastic thymic tissue, whereas its staining was quite low in myasthenia gravis thymomas. The number of Bcl‐2‐positive thymocytes in the medulla was significantly greater in the hyperplastic myasthenia gravis thymic tissue than in the control thymic tissue. These findings suggest that Bcl‐2 protein may be upregulated in the myasthenia gravis thymus and that this phenomenon may be related to impaired apoptotic cell death of autoreactive thymocytes in myasthenia gravis.
The uncertainty in present-day anthropogenic forcing is dominated by uncertainty in the strength of the contribution from aerosol. Much of the uncertainty in the direct aerosol forcing can be ...attributed to uncertainty in the anthropogenic fraction of aerosol in the present-day atmosphere, due to a lack of historical observations. Here we present a robust relationship between total present-day aerosol optical depth and the anthropogenic contribution across two multi-model ensembles and a large single-model perturbed parameter ensemble. Using observations of aerosol optical depth, we determine a reduced likely range of the anthropogenic component and hence a reduced uncertainty in the direct forcing of aerosol.
Tumor necrosis factor (TNF)-alpha-positive cells constituted 1.6-18% and 8.2-23.5% of the total number of cerebrospinal fluid cells from six of 12 patients with HTLV-I-associated myelopathy and in ...all samples obtained from inflammatory cases, respectively. However, in non-inflammatory cases no TNF-alpha-positive cells were detected. These results suggest that some of the infiltrating CSF cells produce TNF-alpha, which plays a role in host immune defenses against causative agents including HTLV-I and in lesion formation within the central nervous system in inflammatory diseases.
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