2,029 research outputs found
Magnetic energy-level diagrams of high-spin (Mn-acetate) and low-spin (V) molecules
The magnetic energy-level diagrams for models of the Mn12 and V15 molecule
are calculated using the Lanczos method with full orthogonalization and a
Chebyshev-polynomial-based projector method. The effect of the
Dzyaloshinskii-Moriya interaction on the appearance of energy-level repulsions
and its relevance to the observation of steps in the time-dependent
magnetization data is studied. We assess the usefulness of simplified models
for the description of the zero-temperature magnetization dynamics
Semaine d'Etude Mathématiques et Entreprises 6 : Représentation des fonctions de réponse radiométrique
Ce rapport rassemble les différentes pistes de réponses apportées au problème posé par l'entreprise Kolor lors de la 6ème Semaine d'Étude Maths-Entreprises de juin 2013. Le problème porte sur la représentation de fonctions de réponse radiométrique utilisées dans de nombreux logiciels de manipulation de photographies. Une grande partie du travail effectué a consisté à comprendre le problème et ses enjeux afin de le formaliser de façon mathématique. Après une description formelle des outils envisagés, nous les évaluons par rapport aux contraintes du problème afin de déterminer leurs avantages et inconvénients. D'un point de vue pratique, les outils sont présentés dans l'objectif d'être éventuellement développés et intégrés à un logiciel existant. Nous avons donc tenté, dans la mesure du possible, de prendre en compte la simplicité de ces outils que ce soit du côté développement ou du côté utilisation. Ce rapport s'articule en six parties. Après une description pratique du problème, nous en détaillons les principales caractéristiques. Dans une troisième partie, nous décrivons les trois outils envisagés. Les deux parties suivantes constituent l'étude des outils par rapport aux contraintes du problème. Finalement nous donnons une conclusion de cette étude
Retroperitoneal liposarcoma associated with small plaque parapsoriasis
<p>Abstract</p> <p>Background</p> <p>Extremely rare cases of paraneoplastic syndromes or ectopic production of proteins associated with liposarcoma are reported in literature. Production of Granulocyte-Colony Stimulating Factor, alpha-fetoprotein, paraneoplastic pemphigus and leucocytosis, Acrokeratosis paraneoplastica (Bazex's syndrome) are reported.</p> <p>The present report describes a case of retroperitoneal liposarcoma associated with small plaque parapsoriasis. Our search in the English literature of such a kind of association did not reveal any case reported.</p> <p>Case presentation</p> <p>A 74 year male patient was admitted to our hospital because of the presence of an abdominal mass in right iliac fossa. He also complained of a two-year history of psoriasiform eruptions. The CT scan showed a retroperitoneal pelvic mass. Therefore surgical resection of the tumor was performed. After surgery, the skin eruptions disappeared completely in seven days and so a diagnosis of parapsoriasis syndrome was done.</p> <p>Conclusion</p> <p>Parallel disappearing of skin eruptions after surgery, typical clinical picture and not specific histology of the cutaneous lesions suggest the diagnosis of small plaque parapsoriasis. Therefore we propose to add Small Plaque Parapsoriasis to the list of paraneoplastic syndromes associated to liposarcoma.</p
An international multicenter retrospective analysis of patients with extranodal marginal zone lymphoma and histologically confirmed central nervous system and dural involvement
Marginal zone lymphoma of the central nervous system (CNS MZL) is rare. The clinical features, treatment, and prognosis are not well characterized. We performed a multicenter retrospective study of CNS MZL. Twenty-six patients were identified: half with primary and half with secondary CNS involvement. The median age was 59 years (range 26-78), 62% female and 79% with ECOG performance status ≤ 1. The most common disease site was the dura (50%). Treatment was determined by the treating physician and varied substantially. After a median follow up of 1.9 years, the estimated 2-year progression-free (PFS) and overall survival (OS) rates were 59% and 80%, respectively. Secondary CNS MZL was associated with 2-year OS of 58%. CNS MZL is rare, but relative to other forms of CNS lymphoma, outcomes appear favorable, particularly among the subset of patients with dural presentation and primary CNS presentation
Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement
<div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div
Influence of deposition strategies on tensile and fatigue properties in a wire + arc additive manufactured Ti-6Al-4V
This paper investigates the influence of two different deposition strategies, oscillation and parallel pass, on the tensile and high cycle fatigue properties of a wire + arc additive manufactured Ti-6Al-4V alloy in the as-built condition. In the oscillation build, the plasma torch and the wire feeder continuously oscillated across the wall thickness direction. In contrast, four single layers were deposited consecutively in the same direction along the wall length in the parallel pass build. Test specimens were manufactured in horizontal and vertical orientation with respect to the deposited layers. Compared with the parallel pass build, the oscillation build had lower static strength due to its coarser transformation microstructure. However, the elongation values were similar. The presence of columnar primary β grains has resulted in anisotropic elongation values. The vertical samples with loading axis parallel to the primary β grains showed 40% higher elongation than the horizontal samples. The fatigue strength was comparable with its wrought counterpart and greater than typical material by casting. At 107 cycles, fatigue strength of 600 MPa was achieved for the oscillation build vertical samples and the parallel pass build in both orientations. Only the oscillation build horizontal samples had lower fatigue strength of 500 MPa. Fractography analysis showed that most of the samples (about 70%) had crack initiation from pores, about 20% samples had crack initiated from microstructural features and the rest did not failed (runouts at 107 cycles)
Critical analysis of salvage radical prostatectomy in the management of radioresistant prostate cancer
The role of microstructure and local crystallographic orientation near porosity defects on the high cycle fatigue life of an additive manufactured Ti-6Al-4V
Titanium alloys such as Ti-6Al-4V built by most of the additive manufacturing processes are known to contain process induced defects, non-conventional microstructure and strong crystallographic texture; all of which can affect the fatigue strength. In this study we evaluated the effect of crystallographic orientation of α and α lath width around gas pore defects on the high cycle fatigue life of Wire + Arc Additive Manufactured Ti-6Al-4V by means of Electron Back Scattered Diffraction. Here we show that variations in crystallographic orientation of α lath and its width in the vicinity of the crack initiating defect were the main reasons for the considerable scatter in fatigue life. Pyramidal slip systems with high Schmid factor active around the defects resulted in longer fatigue life compared to pyramidal slip with lower Schmid factor. In the absence of pyramidal slip, cracks initiated from active prismatic slip systems. When considering the influence of the microstructure, a higher number of smaller α laths around the defect resulted in longer fatigue life, and vice versa. Overall, the fatigue crack initiation stage was controlled collectively by the complex interaction of porosity characteristics, α lath width and its crystallographic orientation at the crack initiation locatio
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