942 research outputs found
In-vitro evaluation of bioactive and biodegradation properties of mesoporous ZnO architectures
No full textCurrently there is strong interest in the development of smart piezoelectric biomaterials for tissue engineering, where piezoelectricity may actively promote the growth, proliferation and differentiation of cells. [1] Piezoelectric Zinc Oxide (ZnO) materials may be easily prepared in high-surface area structures by several techniques, and captured considerable attention due to their biocompatibility and antibacterial properties. [2] Despite being widely investigated for sensors and energy harvesting applications, [3] the study of ZnO-based materials for tissue engineering is still in its infancy. Herein, we propose a preliminary investigation on the in-vitro bioactive and biodegradation behavior of high-surface area mesoporous ZnO layers, after soaking in Simulated Body Fluid (SBF) solution for different times. The ZnO samples were obtained by thermal oxidation of Zn layers sputtered on silicon substrates. The morphology, crystal structure, and chemical composition of the ZnO samples were studied before and after in-vitro tests. Our results show the rapid formation of CaP structures after soaking in SBF for few hours, then resulting into the formation of a CaP-rich layer onto the whole ZnO surface for prolonged soaking times. The mesoporous ZnO architecture was preserved during the overall in-vitro experimental analyses, with negligible release of biodegradation products from the ZnO structure. [1] C. Ribeiro, V. Sencadas, D.M. Correia, and S. Lanceros-Méndez, Colloids. Surf. B, 136 (2015) 46-55. [2] Y. Zhang, T. R. Nayak, H. Hong, and W. Cai, Curr. Mol. Med. 13 (2013) 1633-1645. [3] M. Laurenti, G. Canavese, A. Sacco, M. Fontana, K. Bejtka, M. Castellino, C.F. Pirri, and V. Cauda, Adv. Mater. 27 (2015) 4218-4223
Cauda longa: uma análise para setores
No full textTCC (Graduação) - Universidade Federal de Santa Catarina. Centro Socioeconômico. Curso de Graduação em Ciências Econômicas.O rápido crescimento da Economia Digital está transformando muitos negócios da Economia Tradicional. O que a economia da escassez pode aprender a partir da observação da economia da abundância e o que acontecerá quando tudo no mundo se tornar disponível para todos? Esta pesquisa busca conceituar a Teoria da Cauda Longa, de Chris Anderson (2006), à luz da Economia e da gestão organizacional (Administração e Marketing) para então analisar dois distintos setores tradicionais diante das condições da teoria “digital”. O setor Automobilístico brasileiro e o setor da Aviação Civil brasileira, ambos no ano de 2011, serão analisados sob aspectos mercadológicos para observar se há características em comum entre estes setores e a teoria em questão. O resultado foi avaliado a partir de pesquisa bibliográfica e análise empírica, concluindo que a Economia Tradicional desses setores analisados tem mais em comum com a Economia Digital do que era esperado, mas ainda assim pode explorar melhor a modernidade do estilo de vida atual com conceitos reunidos na Teoria da Cauda Longa.The fast growth of Digital Economy is transforming many Traditional Economy businesses. What shortage economy can learn from observing the abundance economy and what is going to happen when everything in the world becomes available to everyone? This research seeks to conceptualize the Long Tail Theory, from Chris Anderson (2006), at the lights of Economy and organizational management (Business Administration and Marketing) and then analyze two distinct sectors in front of the “digital” theory conditions. The Brazilian Automotive and Commercial Civil Aviation sector, both in 2011 will be analyzed under market aspects in order to observe if there are common characteristics between the sectors and the theory in question. The result was evaluated from the bibliographic search and empiric analysis, concluding that Traditional Economy on these analyzed sectors have more in common with Digital Economy than expected, and can better explore the modernity of present lifestyle with gathered concepts in Long Tail Theory
Interação do zinco com antidepressivos no teste de suspensão da cauda e no teste do campo aberto
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em Neurociências.O efeito tipo-antidepressivo do zinco vem sendo demonstrado em alguns modelos animais de depressão. No presente estudo, cloreto de zinco (ZnCl2) foi administrado, sozinho ou em combinação com diferentes antidepressivos, por via oral (p.o.), em camundongos, e a resposta comportamental no teste de suspensão da cauda (TSC), teste preditivo de atividade antidepressiva, e no teste do campo aberto foi investigada. ZnCl2 administrado nas doses de 10 e 30 mg/kg, p.o., 60 minutos antes dos testes comportamentais, reduziu o tempo de imobilidade no TSC, sem afetar a atividade locomotora no teste do campo aberto. Além disso, ZnCl2 (30 mg/kg, p.o.) apresentou efeito tipo-antidepressivo quando foi administrado 30' antes do TSC. Os antidepressivos fluoxetina, paroxetina, imipramina, desipramina e bupropiona produziram uma significativa redução no tempo de imobilidade no TSC nas doses de 10; 1; 1;1;10 mg/kg, p.o., respectivamente. O tratamento combinado de doses sub-efetivas de ZnCl2 (1 mg/kg) com doses sub-efetivas de fluoxetina (5 mg/kg), paroxetina (0,1 mg/kg), desipramina (0,1 mg/kg), imipramina (0,1 mg/kg), ou bupropiona (1 mg/kg) gerou uma significativa redução no tempo de imobilidade no TSC, quando comparado com grupos tratados com o veículo, ZnCl2 ou antidepressivos sozinhos. O tratamento com ZnCl2 e antidepressivos sozinhos ou em combinação não afetou a locomoção dos animais submetidos ao teste do campo aberto, exceto a desipramina que administrada sozinha reduziu a locomoção dos animais. O tratamento com desipramina (0,1 mg/kg) ou paroxetina (0,1 mg/kg) sozinhos reduziu o número de respostas de levantamento vertical ("rearings") no teste do campo aberto. O tratamento com bupropiona (1 mg/kg) ou desipramina (0,1 mg/kg) sozinhos reduziu o número de respostas de auto-limpeza dos animais submetidos ao teste do campo aberto. Ainda, a administração combinada de ZnCl2 com bupropiona também diminuiu o número de respostas de auto-limpeza, condizente com um efeito semelhante a de benzodiazepínicos (ansiolíticos). Os resultados indicam, inicialmente, que o ZnCl2 administrado por via oral produz um efeito tipo-antidepressivo no TSC. Além disso, efeitos sinérgicos da administração de ZnCl2 com antidepressivos em diferentes classes foi mostrado no TSC, sugerindo que uma melhora na terapia antidepressiva clássica ocorra quando o zinco é acrescentado ao tratamento realizado com antidepressivos. Ainda, a combinação de ZnCl2 com o inibidor da recaptação de dopamina bupropiona diminuiu o número de auto-limpeza de animais submetidos ao teste do campo aberto, sugerindo que esta combinação seja efetiva no tratamento de pacientes aonde a depressão coexista com a ansiedade
Actin localisation and the effect of cytochalasin D on the osmotic tolerance of cauda epedidymidal kangaroo spermatozoa
No full textThis study examined the hypothesis that filamentous actin associated with the complex cytoskeleton of the kangaroo sperm head and tail may be contributing to lack of plasma membrane plasticity and a consequent loss of membrane integrity during cryopreservation. In the first study, the distribution of G and F actin within Eastern Grey Kangaroo (EGK, Macropus giganteus) cauda epididymidal spermatozoa was successfully detected using DNAse-FITC and a monoclonal F-actin antibody (ab205, Abcam), respectively. G-actin staining was most intense in the acrosome but was also observed with less intensity over the nucleus and mid-piece. F-actin was located in the sperm nucleus but was not discernable in the acrosome or sperm tail. To investigate whether cytochalasin D (a known F-actin depolymerising agent) was capable of improving the osmotic tolerance of EGK cauda epididymal spermatozoa, sperm were incubated in hypo-osmotic media (61 and 104 mOsm) containing a range of cytochalasin D concentrations (0-200 mu M). Cytochalasin D had no beneficial effect on plasma membrane integrity of sperm incubated in hypo-osmotic media. However, when EGK cauda epididymidal sperm were incubated in isosmotic media, there was a progressive loss of sperm motility with increasing cytochalasin D concentration. The results of this study indicated that the F-actin distribution in cauda epididymidal spermatozoa of the EGK was surprisingly different from that of the Tammar Wallaby (M. eugenii) and that cytochalasin-D does not appear to improve the tolerance of EGK cauda epididymidal sperm to osmotically induced injury
Treatment of skin and soft tissue infections due to community-associated methicillin-resistant Staphylococcus aureus in Europe: the role of trimethoprim-sulfamethoxazole0010
No full textNo abstract availabl
Intralesional and subarachnoid bleeding of a spinal schwannoma presenting with acute cauda equina syndrome
No full textWe present an unusual case of spinal neurinoma with intralesional and subarachnoid bleeding with acute cauda equina syndrome. A 38-year-old man was admitted to our department after a minor thoracic spinal trauma with right lower limb plegia and urinary retention. MRI showed a T11 intradural tumour with intralesional and subarachnoid haemorrhage. The patient was operated of spinal cord decompression and complete tumour resection. The histological examination documented a schwannoma with large haemorrhagic intratumoural areas. A full neurological recovery was documented at 6-month follow-up
Activation Likelihood Estimation meta-analysis of brain correlates of placebo analgesia in human experimental pain
No full textPlacebo analgesia (PA) is one of the most studied placebo effects. Brain imaging studies published over the last decade, using either positron emission tomography (PET) or functional magnetic resonance imaging (fMRI), suggest that multiple brain regions may play a pivotal role in this process.However, there continues to be much debate as to which areas consistently contribute to placebo analgesia-related networks. In the present study, we used activation likelihood estimation (ALE) meta-analysis, a state-of-the-art approach, to search for the cortical areas involved in PA in human experimental pain models. Nine fMRI studies and two PET studies investigating cerebral hemodynamic changes were included in the analysis. During expectation of analgesia, activated foci were found in the left anterior cingulate, right precentral, and lateral prefrontal cortex and in the left periaqueductal gray (PAG). During noxious stimulation, placebo-related activations were detected in the anterior cingulate and medial and lateral prefrontal cortices, in the left inferior parietal lobule and postcentral gyrus, anteriorinsula, thalamus, hypothalamus, PAG, and pons; deactivations were found in the left mid- and posterior cingulate cortex, superior temporal and precentral gyri, in the left anterior and right posterior insula, in the claustrum and putamen, and in the right thalamus and caudate body. Our results suggest on one hand that the modulatory cortical networks involved in PA largely overlap those involved in the regulation of emotional processes, on the other that brain nociceptive networks are downregulatedin parallel with behavioral analgesia
The Foraging Brain: Evidence of Lévy Dynamics in Brain Networks.
No full textIn this research we have analyzed functional magnetic resonance imaging (fMRI) signals of different networks in the brain under resting state condition. To such end, the dynamics of signal variation, have been conceived as a stochastic motion, namely it has been modelled through a generalized Langevin stochastic differential equation, which combines a deterministic drift component with a stochastic component where the Gaussian noise source has been replaced with α-stable noise. The parameters of the deterministic and stochastic parts of the model have been fitted from fluctuating data. Results show that the deterministic part is characterized by a simple, linear decreasing trend, and, most important, the α-stable noise, at varying characteristic index α, is the source of a spectrum of activity modes across the networks, from those originated by classic Gaussian noise (α = 2), to longer tailed behaviors generated by the more general Lévy noise (1 ≤ α < 2). Lévy motion is a specific instance of scale-free behavior, it is a source of anomalous diffusion and it has been related to many aspects of human cognition, such as information foraging through memory retrieval or visual exploration. Finally, some conclusions have been drawn on the functional significance of the dynamics corresponding to different α values
Temporal and spatial neural dynamics in the perception of basic emotions from complex scenes.
No full textThe different temporal dynamics of emotions are critical to understand their evolutionary role in the regulation of interactions with the surrounding environment. Here, we investigated the temporal dynamics underlying the perception of four basic emotions from complex scenes varying in valence and arousal (fear, disgust, happiness and sadness) with the millisecond time resolution of Electroencephalography (EEG). Event-related potentials were computed and each emotion showed a specific temporal profile, as revealed by distinct time segments of significant differences from the neutral scenes. Fear perception elicited significant activity at the earliest time segments, followed by disgust, happiness and sadness. Moreover, fear, disgust and happiness were characterized by two time segments of significant activity, whereas sadness showed only one long-latency time segment of activity. Multidimensional scaling was used to assess the correspondence between neural temporal dynamics and the subjective experience elicited by the four emotions in a subsequent behavioral task. We found a high coherence between these two classes of data, indicating that psychological categories defining emotions have a close correspondence at the brain level in terms of neural temporal dynamics. Finally, we localized the brain regions of time-dependent activity for each emotion and time segment with the low-resolution brain electromagnetic tomography. Fear and disgust showed widely distributed activations, predominantly in the right hemisphere. Happiness activated a number of areas mostly in the left hemisphere, whereas sadness showed a limited number of active areas at late latency. The present findings indicate that the neural signature of basic emotions can emerge as the byproduct of dynamic spatiotemporal brain networks as investigated with millisecond-range resolution, rather than in time-independent areas involved uniquely in the processing one specific emotion
The shielding effect of phospholipidic bilayers on zinc oxide nanocrystals for biomedical applications
No full textZinc oxide nanocrystals (ZnO NCs), thanks to their unique properties, are receiving much attention for their use in nanomedicine, in particular for therapy against cancer [1]. To be efficiently employed as diagnostic and therapeutic (yet theranostic) tools [2], highly dispersed, stable and non-toxic nanoparticles are required. In the case of ZnO NCs, there is still a lack of knowledge about cytotoxicity mechanisms and stability in the biological context, as well as immunological response and haemocompatible features. Most of these above-mentioned behaviours strongly depends on physico-chemical and surface properties of the nanoparticles. We thus propose a novel approach to stabilize the ZnO NCs in various biological media, focusing on NC aggregation and biodegradation as a function of the surface functionalization. We synthesized bare ZnO NCs, amino-propyl functionalized ones, and lipid bilayer-shielded NCs, and we characterized their morphological, chemical and physical properties. The stability behavior of the three different samples was evaluated, comparing their biodegradation profiles in different media, i.e. organic solvents, water, and different simulated and biological fluids. The studies aim to investigate how the particle surface functionalizations, and thus chemistry and charge, could influence their hydrodynamic size, zeta potential and consequent aggregation and degradation in the different solvents. We demonstrated that bare and amino-functionalized ZnO NCs strongly and rapidly aggregate when suspended in both simulated and biological media. Long-term biodegradation analysis showed small dissolution into potentially cytotoxic Zn-cations, also slightly affecting their crystalline structure. In contrast, high colloidal stability and integrity was retained for lipid-shielded ZnO NCs in all media, rendering them the ideal candidates for further theranostic applications [3]. [1] P. Zhu, Z. Weng, X. Li, X. Liu, S. Wu Adv. Mater. Interfaces 3 (2016) 1500494. [2] E. Lim, T. Kim, S. Paik, S. Haam, Y. Huh, and K. Lee, Chem. Rev. 115 (2015) 327−394. [3] B. Dumontel, M. Canta, H. Engelke, A. Chiodoni, L. Racca, A. Ancona, T. Limongi, G. Canavese and V. Cauda, J. Mater. Chem. B, under review The support from ERC Starting Grant - Project N. 678151 "Trojananohorse" and Compagnia di Sanpaolo are gratefully acknowledged
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