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[en] Hemangiopericytoma (HPRC) are tumors derived from pericytes, cells normally present around normal capillaries and may involve any part of the body. The intracranial incidence of this tumor is small, and in these cases they derive from the meninges, not invading the brain tissue. Although once considered only an angioblastic variant of meningeoma, immuno-histochemical and ultrastructural studies have put it as a distinct pathological entity. This paper present, the case of a HPRC primary from the clavicle, later metastasizing to the skull. Neuroradiological and histopathological aspects are considered, and compared with those of the literature. This paper concluded: a) the selective angiography of the carotid artery is more useful for the diagnosis and surgical planning; b) HPRC are highly invasive tumors, with high rates of reincidence and metastasis; we consider that surgical excision should be radical, except when there is risk of cerebral vascular impairment or when there is invasion of major dural sinuses; c) there is, yet, no consensus about the use of complementary radiotherapy. (author)
[en] Negative compressibility is the ability to expand in at least one dimension rather than shrinking upon the application of an externally applied hydrostatic pressure. It is shown that, contrary to current perception, negative linear compressibility may be obtained from re-entrant hexagonal truss systems of specific geometric features which deform through non-equal changes in the lengths of the cell walls when deforming through a constrained angle stretching rather than other modes of deformation (such as flexure or hinging, modes of deformation that also lead to auxetic behaviour in honeycombs). Negative compressibility is predicted in the vertical direction for particular re-entrant geometries of this smart hexagonal truss system when the vertical ribs are much stiffer than the inclined ribs. (paper)
[en] The impact of bread fortification with β-glucans and with proteins/proteolytic enzymes from brewers’ spent yeast on physical characteristics was evaluated. β-Glucans extraction from spent yeast cell wall was optimized and the extract was incorporated on bread to obtain 2.02 g β-glucans/100 g flour, in order to comply with the European Food Safety Authority guidelines. Protein/proteolytic enzymes extract from spent yeast was added to bread at 60 U proteolytic activity/100 g flour. Both β-glucans rich and proteins/proteolytic enzymes extracts favoured browning of bread crust. However, breads with proteins/proteolytic enzymes addition presented lower specific volume, whereas the incorporation of β-glucans in bread lead to uniform pores that was also noticeble in terms of higher specific volume. Overall, the improvement of nutritional/health promoting properties is highlighted with β-glucan rich extract, not only due to bread β-glucan content but also for total dietary fibre content (39% increase). The improvement was less noticeable for proteins/proteolytic enzymes extract. Only a 6% increase in bread protein content was noted with the addition of this extract and higher protein content would most likely accentuate the negative impact on bread specific volume that in turn could impair consumer acceptance. Therefore, only β-glucan rich extract is a promising bread ingredient.
[en] Time-lapse X-ray computed microtomography was employed to quantify the deformation behaviour of closed-cell aluminium foam. The specimen was incrementally loaded and tomographically scanned using a custom X-ray tomographic device to capture the deforming microstructure. Because of the very small thickness of the cell walls and the high ratio between pore size and cell wall thickness cone-beam reconstruction procedure was applied. A finite element (FE) model was developed based on the reconstructed three-dimensional data. The FE model was used for two purposes: i) the nodal points were used for tracking the displacements of the deforming structure, ii) verification of the material model for description of the foam's deformational behaviour. Digital volumetric correlation (DVC) algorithm was used on data obtained from the time-lapse tomography to provide a detailed description of the evolution of deformation in the complex structure of aluminium foam. The results from DVC demonstrate the possibility to use the complex microstructure of the aluminium foam as a random pattern for the correlation algorithm. The underlying FE model enables easy comparison between experimental results and results obtained from numerical simulations used for evaluation of proposed constitutive models.
[en] The present work studies the effect of Palygorskite content on the water absorption kinetics and cellular structure of polypropylene. These foams were obtained by a single extrusion process (simultaneous formulation and foaming), using as chemical foaming agent: azodicarbonamide at 1%, and maleic anhydride grafted polypropylene as compatibilizer. The cellular structure of the foams was characterized by scanning electron microscopy; also, the water absorption of the foams was measured at long-terms. It was found that the clay content increases cell size and diminishes the nucleation density of the foams; the cellular structure changes from closed cells to open cells. The absorption kinetics is affected by the cellular structure, the presence of micropores in the cell wall and the Palygorskite content. The foam with 1% of clay absorbed the greatest quantity of water. (paper)
[en] Dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance (NMR) has recently emerged as a powerful technique for the study of material surfaces. In this study, we demonstrate its potential to investigate cell surface in intact cells. Using Bacillus subtilis bacterial cells as an example, it is shown that the polarizing agent 1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol (TOTAPOL) has a strong binding affinity to cell wall polymers (peptidoglycan). This particular interaction is thoroughly investigated with a systematic study on extracted cell wall materials, disrupted cells, and entire cells, which proved that TOTAPOL is mainly accumulating in the cell wall. This property is used on one hand to selectively enhance or suppress cell wall signals by controlling radical concentrations and on the other hand to improve spectral resolution by means of a difference spectrum. Comparing DNP-enhanced and conventional solid-state NMR, an absolute sensitivity ratio of 24 was obtained on the entire cell sample. This important increase in sensitivity together with the possibility of enhancing specifically cell wall signals and improving resolution really opens new avenues for the use of DNP-enhanced solid-state NMR as an on-cell investigation tool. (authors)
[en] Complete text of publication follows. Objective: Low doses of gamma irradiation can induce physiological and biochemical changes, resulting in faster vegetative growth and early flowering. However, there is no report on the relationship between low dose gamma irradiation and cell wall formation. Therefore, it is necessary for investigating the effect of gamma irradiation on cell wall formation. Materials and Methods: Dry seeds (Arabidopsis thaliana L.) were irradiated at 0-200 Gy by gamma-ray irradiator (60Co, ca.150 TBq of capacity, AECL). The plants were grown in the Chungbuk National University green house facilities. The extract free residues were performed various experiments such as germination and growth rates, lignin content, alkaline nitrobenzene oxidation (NBO), neutral sugar composition, and histochemical analyses. Results and Conclusion: The first experiment on seeds exposed to relatively low and high doses of ionizing radiation (0-200 Gy) was performed to select optimum dose of stimulating effect. The optimum dose based on the results of germination and growth rates is 40 Gy. Nineteen days after sowing (DAS), seeds exposed to 40 and 200 Gy showed a departure from the stem height and lignin content of the control. Seeds exposed to 40 Gy were significantly higher stem height and lignin content than control. In contrast, significant decreases occurred in both stem height and lignin content at 200 Gy. These differences continued for up to 31 DAS. Interestingly, all plants return to normal in terms of stem height and lignin content from 34 DAS. These results were confirmed by analyses of lignin units. The predominant lignin units such as guaiacyl and syringyl units were very similar to the trend of stem height and lignin content. In addition, morphological changes at 40 and 200 Gy were performed by histochemical analysis. Seeds exposed to 40 Gy were well developed xylem region, while 200 Gy irradiated samples were relatively inhibited xylem from development.
[en] Human milk has always been considered an ideal source of elemental nutrients to both preterm and full term infants in order to optimally develop the infant's tissues and organs. Recently, hundreds of endogenous milk peptides were identified in human milk. These peptides exhibited angiotensin-converting enzyme inhibition, immunomodulation, or antimicrobial activity. Here, we report the antimicrobial activity and mechanism of a novel type of human antimicrobial peptide (AMP), termed PDC213 (peptide derived from β-Casein 213-226 aa). PDC213 is an endogenous peptide and is present at higher levels in preterm milk than in full term milk. The inhibitory concentration curve and disk diffusion tests showed that PDC213 had obvious antimicrobial against S. aureus and Y. enterocolitica, the common nosocomial pathogens in neonatal intensive care units (NICUs). Fluorescent dye methods, electron microscopy experiments and DNA-binding activity assays further indicated that PDC213 can permeabilize bacterial membranes and cell walls rather than bind intracellular DNA to kill bacteria. Together, our results suggest that PDC213 is a novel type of AMP that warrants further investigation. - Highlights: • PDC213 is an endogenous peptide presenting higher levels in preterm milk. • PDC213 showed obvious antimicrobial against S. aereus and Y. enterocolitica. • PDC213 can permeabilize bacterial membranes and cell walls to kill bacterias. • PDC213 is a novel type of antimicrobial peptides worthy further investigation.