Sphenoethmoidal mucoceles with intracranial extension--three case reports

Three unusual cases of sphenoethmoidal mucoceles with rare intracranial extension are reported. A 64-year-old female presented with a 7-month history of right visual disturbance. Computed tomography (CT) and magnetic resonance (MR) imaging demonstrated a huge mass in the right middle fossa. She underwent right frontotemporal craniotomy. Postoperatively, her proptosis and cranial nerve dysfunction had improved markedly. A 53-year-old female complained of headache, nausea, and dizziness. CT and MR imaging revealed a cystic mass filling the right sphenoid sinus. The cystic lesion was evacuated through the transnasal approach. She was doing well postoperatively and has been asymptomatic. A 39-year-old male complained of headache, vomiting, and right visual disturbance. CT and MR imaging demonstrated a homogeneous mass occupying the sphenoid sinus. Sphenoidotomy exposed the cyst extending superiorly into the anterior cranial fossa. He recovered from the visual disturbances and has been asymptomatic since. MR imaging provides confirmation of the diagnosis of sphenoethmoidal mucocele and is important for preoperative evaluation.     

A configuration deactivation algorithm for boosting probabilistic roadmap planning of robots

We present a method to improve the execution time used to build the roadmap in probabilistic roadmap planners. Our method intelligently deactivates some of the configurations during the learning phase and allows the planner to concentrate on those configurations that are most likely going to be useful when building the roadmap. The method can be used with many of the existing sampling algorithms. We ran tests with four simulated robot problems typical in robotics literature. The sampling methods applied were purely random, using Halton numbers, Gaussian distribution, and bridge test technique. In our tests, the deactivation method clearly improved the execution times. Compared with pure random selections, the deactivation method also significantly decreased the size of the roadmap, which is a useful property to simplify roadmap planning tasks.     

The effect of mental workload on the visual field size and shape.

Mental workload is known to reduce the area of one's visual field, but little is known about its effects on the shape of the visual field. Considering this, the visual fields of 13 subjects were measured concurrently under three levels of mental workload using a Goldmann visual perimeter. Tone counting tasks were employed to induce mental workload, avoiding interference with visual performance. Various methods of shape measurement and analysis were used to investigate the variation of the shape of the visual field as a function of mental load. As expected, the mean area of visual fields reduced to 92.2% in the medium workload condition and to 86.41% under heavy workload, compared to light load condition. This tunnelling effect was not uniform, but resulted in statistically significant shape distortion as well, as measured by the majority of the 12 shape indices used here. These results have visual performance implications in many tasks that are susceptible to changes in visual fields and peripheral vision. Knowledge of the dynamics of the visual field as a function of mental workload can offer significant advantages also in mathematical modelling of visual search.     

Granulocyte-macrophage colony stimulating factor suppresses lipopolysaccharide-induced osteoclast-like cell formation in mouse bone marrow cultures

Lipopolysaccharide (LPS) is a potent bone resorbing factor. We investigated the effect of LPS on osteoclast formation in three types of cultures. LPS inhibited osteoclast formation induced by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], in a dose-dependent manner, in cultures of whole bone marrow cells without dexamethasone. LPS increased the amount of granulocyte-macrophage colony stimulating factor (GM-CSF) in the culture supernatant, and anti-GM-CSF antiserum almost abolished the inhibition of osteoclast formation by LPS, thereby indicating that GM-CSF generated by treatment with LPS may be responsible for the inhibition of osteoclast formation. In cultures with dexamethasone, the amount of GM-CSF was decreased to one-third of that with 1,25(OH)2D3 alone and was not changed by treatment with LPS. In this culture system, LPS enhanced osteoclast formation. In the coculture system of nonadherent bone marrow cells and a stromal cell line in the presence of 1,25(OH)2D3 and dexamethasone, where no detectable GM-CSF was present in the supernatant, LPS markedly enhanced osteoclast formation, whereas exogenously added GM-CSF (100 pg/ml) almost completely inhibited osteoclast formation. LPS stimulated pit formation on dentin slices by the osteoclast-like cells formed by in vitro culture system.     

Using probabilistic roadmaps in changing environments

In this paper, we examine how a path planning problem can be solved in changing environments using probabilistic roadmap planners. A probabilistic roadmap is built in static environment where all obstacles are known in advance, but we show that a roadmap can be built in such a way that it works well even when new obstacles are added to the workspace. However, our experiments show that the roadmap graph must be built carefully. We compare three different methods that are used to decide which edges are added to the roadmap graph to connect the nodes. One of these is a distance‐based method, which we present in this paper. In the tests, we built a roadmap by using only the static obstacles. Then, we added additional obstacles to the environment and tested how well the roadmap still worked. The tests showed that our distance‐based method worked quickly and that it produced roadmaps, which could be used to find a path amid additional obstacles with a high success rate.Copyright © 2013 John Wiley & Sons, Ltd.