200 research outputs found

    Management of Obstructive Hydrocephalus Associated with Pineal Region Cysts and Tumors and Its Implication in Long-Term Outcome

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    BACKGROUND: Different treatment options have been proposed for obstructive hydrocephalus associated with pineal lesions. We discuss the obstructive hydrocephalus management associated with pineal region tumors and cysts in Helsinki Neurosurgery. METHODS: In this article, hydrocephalus treatment by tumor-cyst removal (n = 40), shunt surgery (n = 25), and endoscopic ventriculostomies (n = 3) is evaluated in 68 patients with obstructive hydrocephalus among 136 patients with pineal region tumor and cyst. Multivariate statistical analysis was followed by univariate and multivariate regression models of last functional status, last tumor-free imaging, and disease-specific mortality of the study population. RESULTS: Preoperative hydrocephalus was linked to higher World Health Organization tumor grades, poor functional status, higher mortality, and incomplete resection of pineal region cysts and tumors. Preoperative hydrocephalus remained a predictor of poor last functional status after multivariate regression. Pineal lesion removal with the posterior third ventricle opening as primary hydrocephalus treatment resulted in better last functional status, fewer postoperative shunts, fewer hydrocephalus related procedures, and fewer postoperative infections than in the shunt-treatment group. Multivariate regression analysis linked higher World Health Organization tumor & nbsp;grade, poor immediate functional status, postoperative complications, and incomplete surgical resection as independent predictors of disease mortality in patients with hydrocephalus. Same variables (except immediate modified Rankin Scale score) and higher number of shunt surgeries became independent predictors of poor last functional status at multivariate analysis. Incomplete resection was the only independent predictor of tumor-free magnetic resonance imaging at the last evaluation. CONCLUSIONS: Direct removal of pineal lesions with the opening of the posterior third ventricle could represent effective and reliable management of the associated obstructive hydrocephalus. Further research is required to generalize our inferences.Peer reviewe

    Water-soluble polyphosphonate-based bottlebrush copolymers via aqueous ring-opening metathesis polymerization

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    Ring-opening metathesis polymerization (ROMP) is a versatile method for synthesizing complex macromolecules from various functional monomers. In this work, we report the synthesis of water-soluble and degradable bottlebrush polymers, based on polyphosphoesters (PPEs) via ROMP. First, PPE-macromonomers were synthesized via organocatalytic anionic ring-opening polymerization of 2-ethyl-2-oxo-1,3,2-dioxaphospholane using N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide as the initiator and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the catalyst. The resulting norbornene-based macromonomers had degrees of polymerization (DPn) ranging from 25 to 243 and narrow molar mass dispersity (Đ ≤ 1.10). Subsequently, these macromonomers were used in ROMP with the Grubbs 3rd-generation bispyridyl complex (Ru-G3) to produce a library of well-defined bottlebrush polymers. The ROMP was carried out either in dioxane or in aqueous conditions, resulting in well-defined and water-soluble bottlebrush PPEs. Furthermore, a two-step protocol was employed to synthesize double hydrophilic diblock bottlebrush copolymers via ROMP in water at neutral pH-values. This general protocol enabled the direct combination of PPEs with ROMP to synthesize well-defined bottlebrush polymers and block copolymers in water. Degradation of the PPE side chains was proven resulting in low molar mass degradation products only. The biocompatible and biodegradable nature of PPEs makes this pathway promising for designing novel biomedical drug carriers or viscosity modifiers, as well as many other potential applications.</p

    Nunduva, a new marine genus of Rivulariaceae (Nostocales, Cyanobacteria) from marine rocky shores

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    Several populations of a non–tapering and tapering, fasciculated, single and geminate false branch- ing heterocytous cyanobacterium were collected from rocky shores in the Pacific Ocean and Gulf of Mexico. The populations were provisionally placed in Brasilonema based on morphology, but upon sequencing of both environmental and culture material it was discovered that the populations/cultures belonged to the Rivulariaceae, in a marine subclade of the family containing Kyrtuthrix huatulcensis. In culture, the taxon exhibited tapering in isopolar filaments, providing further evidence that it was a member of the rivulariacean clade. Based on molecular data for other cyanobacteria within the rivulariacean clade, we identified at least three more species morphologically distinguishable from the Brasilonema–like material, all of which show more pronounced ta- pering. These cyanobacteria include not only tropical marine strains, but also a strain isolated from the English coastline in the Atlantic Ocean. We propose a new genus and four species for members of this distinctive clade, Nunduva fasciculata gen. nov., sp. nov., N. kania sp. nov., N. biania sp. nov., and N. britannica sp. nov. Other strains that others and we have isolated are sister to Nunduva and may eventually be placed within this genus, but at present, we consider the evidence for inclusion in Nunduva to be insufficient

    WHEN WILL TAXONOMIC SATURATION BE ACHIEVED? A CASE STUDY IN NUNDUVA AND KYRTUTHRIX (RIVULARIACEAE, CYANOBACTERIA)1

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    A number of heterocytous, mat-forming, tapering cyanobacteria in Rivulariaceae have recently been observed in both the Atlantic and Pacific coasts in the rocky intertidal and supratidal zones. These belong to the genera Nunduva, Kyrtuthrix, and Phyllonema and have been the subject of several recent studies. Herein, two new species of Nunduva (N. komarkovae and N. sanagustinensis) and two new species of Kyrtuthrix (K. munecosensis and K. totonaca) are characterized and described from the coasts of Mexico. Genetic separation based on the 16S-23S ITS region was pronounced (\u3e10% in all comparisons). Morphological differences between all existing species in these two genera were also observed, but the group is morphologically complex, and these taxa are considered pseudocryptic. Nunduva and Kyrtuthrix remain morphologically and phylogenetically separate even with the addition of new species. However, how long will this remain the case? Many new genera and species of cyanobacteria have recently been described. Will the taxonomy of cyanobacteria eventually become saturated? Will we start to see multiple populations for the same cryptic species, or will future taxonomists collapse multiple species into fewer species, or multiple genera into single genera. The description of even more Nunduva and Kyrtuthrix species causes us to pause and evaluate the future of cyanobacterial taxonomy. These same questions are faced by algal taxonomists studying other phyla, and the resolution may ultimately be similar

    Novel Method for Wind Turbines Blades Damage Classification using Image Processing

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    Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge

    Novel Method for Wind Turbines Blades Damage Classification using Image Processing

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    75-79Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge
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