Giant intracranial arteriovenous malformation : a case report

Intracranial arteriovenous malformations (AVMs) occur in 0.5-1% of the population [1]. An arteriovenous malformation is a tangled cluster of vessels, in which arteries connect directly to veins with no intervening capillary bed. Because an intracranial hemorrhage, or, rarely, a seizure are the first clinical symptoms of AVMs, they are the most dangerous congenital vascular malformations [1, 3, 4, 5]. We report a case of a 37-year-old woman with a giant intracranial arteriovenous malformation, who complained of headache attacks. The lesion was diagnosed in computed tomography and computed angiotomography of the head. The first imaging study in patients with suspected AVM is usually CT or angio-CT. These studies are good for depicting an AVM, and they are relatively noninvasive. However, angiography used for the diagnosis and planned treatment is invasive. The authors present also the options for therapy

Magnetization dynamics and coherent spin manipulation of a propeller Gd(III) complex with the smallest helicene ligand

A homoleptic gadolinium(III) complex with the smallest helicene-type ligand, 1,10-phenanthroline-N,N'-dioxide (phendo) [Gd(phendo)(4)](NO3)(3)center dot xMeOH (phendo = 1,10-phenanthroline-N,N'-dioxide, MeOH = methanol), shows slow relaxation of the magnetization characteristic for Single Ion Magnets (SIM), despite negligible magnetic anisotropy, confirmed by ab initio calculations. Solid state dilution magnetic and EPR studies reveal that the magnetization dynamics of the [Gd(phendo)(4)](3+) cation is controlled mainly by a Raman process. Pulsed EPR experiments demonstrate long phase memory times (up to 2.7 mu s at 5 K), enabling the detection of Rabi oscillations at 20 K, which confirms coherent control of its spin state.</p

Obraz radiologiczny dużego potworniaka śródpiersia przedniego

Background: Teratomas belong to germ cell tumors. They are frequently found in gonads, but appear as well in mediastinum and other locations. They are usually benign. Case report: We present a case of a 51-year-old male patient with big teratoma in the anterior mediastinum, which was diagnosed a long time ago. This lesion was found on Computed Tomography examination, surgically resected and histopathologically confirmed. Conclusions: CT findings of teratomas are characteristic enough to allow a diagnosis of high probability. Surgical resection is a sufficient treatment

A queueing model for managing small projects under uncertainties

We consider a situation in which a home improvement project contractor has a team of regular crew members who receive compensation even when they are idle. Because both projects arrivals and the completion time of each project are uncertain, the contractor needs to manage the utilization of his crews carefully. One common approach adopted by many home improvement contractors is to accept multiple projects to keep his crew members busy working on projects to generate positive cash flows. However, this approach has a major drawback because it causes "intentional" (or foreseeable) project delays. Intentional project delays can inflict explicit and implicit costs on the contractor when frustrating customers abandon their projects and/or file complaints or lawsuits. In this paper, we present a queueing model to capture uncertain customer (or project) arrivals and departures, along with the possibility of customer abandonment. Also, associated with each admission policy (i.e., the maximum number of projects that the contractor will accept), we model the underlying tradeoff between accepting too many projects (that can increase customer dissatisfaction) and accepting too few projects (that can reduce crew utilization). We examine this tradeoff analytically so as to determine the optimal admission policy and the optimal number of crew members. We further apply our model to analyze other issues including worker productivity and project pricing. Finally, our model can be extended to allow for multiple classes of projects with different types of crew members

Model-based assessment of energy-efficiency, dependability, and cost-effectiveness of waste heat recovery systems onboard ship

YesTechnological systems are not merely designed with a narrow function in mind. Good designs typically aim at reducing operational costs, e.g. through achieving high energy efficiency and improved dependability (i.e. reliability, availability and maintainability). When there is a choice of alternative design options that perform the same function, it makes sense to compare alternatives so that the variant that minimises operational costs can be selected. In this paper, we examine this issue in the context of the design of Waste Heat Recovery Systems (WHRS) for main engines of large commercial freight vessels. We propose a method that can predict the operational cost of a WHRS via thermodynamic analysis which shows costs related to energy utilisation, and dependability analysis which shows costs related to system unavailability and repair. Our approach builds on recent advances in thermodynamic simulation and compositional dependability analysis techniques. It is a model-based approach, and allows reuse of component libraries, and a high degree of automation which simplify application of the method. Our case study shows that alternative designs can be explored in fast iterations of this method, and that this facilitates the evidence-based selection of a design that minimises operational costs