Polymorphic-induced transformations in CaTa2O6 single-crystal fibers obtained by laser-heated pedestal growth

Calcium tantalite (CaTa2O6) single crystal fibers were obtained by the laser-heated pedestal growth method (LHPG). At room temperature, this material can present three polymorphic modifications. The rapid crystallization inherent to the LHPG method produced samples within the Pm3 space group, with some chemical disorder. In order to check for polymorphic-induced transformations, the CaTa2O6 fibers have been submitted to different thermal treatments and investigated by micro-Raman spectroscopy. For short annealing times (15 min) at 1200 °C, the cubic modification was maintained, though with an improved crystalline quality, as evidenced by the enhanced inelastic scattered intensity (by ca. 250%) and narrowing of Raman bands. The polarized Raman spectra respected very well the predicted symmetries and the selection rules for this cubic modification. On the other hand, long annealing times (24 h) at 1200 °C led to a complete (irreversible) polymorphic transformation. The Raman bands became still more intense (ca. 15 times larger than for the as-grown fibers), narrower, and several new modes appeared. Also, the spectra became unpolarized, demonstrating a polycrystalline nature of the transformed crystals. The observed Raman modes could be fully assigned to an orthorhombic modification of CaTa2O6 belonging to the Pnma space group.

A Correlação entre diferentes temperaturas e períodos de preservação sobre as fibras colágenas de meniscos de coelhos

Objetivo: Quantificar as fibras colágenas de meniscos de coelhos submetidos à temperaturas e períodos de preservação variáveis. Métodos: Retirou-se assepticamente 120 meniscos (mediais e laterais) de 30 coelhos (Nova Zelândia), machos, idade entre 6/8 meses, peso médio de 3250g. Os meniscos foram congelados, de dois até trinta dias, a 7,2°Celsius negativos (n=60) e 73°Celsius negativos (n=60). A cada dois dias, de cada temperatura, foram descongelados quatro meniscos que foram encaminhados para o estudo histológico. A descrição morfológica foi feita com os cortes corados por HE, e para o estudo morfométrico os cortes foram corados pelo método de Picrosirius e posteriormente submetidos à polarização. A quntificação de área ocupada pelas fibras colágenas em cada lâmina foi calculada por subtração de imagens à partir do programa de software Image Pro Plus. Resultados: Na análise descritiva das médias percentuais de colágeno foram observadas diferenças maiores e estatisticamente significantes (p<0,001) à temperatura de 73ºCelsius negativos. A análise comparativa das médias percentuais de fibras colágenas ao longo dos períodos de preservação, embora com diferença de valores, apresentaram uma curva simétrica de variação. Também obervou-se que à partir do 14ºdia, em ambas temperaturas, a variação na porcentagem de fibras colágenas em relação aos demais períodos, não apresenta significância estatística, contudo a temperatura de 73ºCelsius negativos mostrou-se superior à 7,2ºCelsius negativos na preservação de fibras colágenas. A análise de regressão polinomial mostrou que a variação das médias percentuais de fibras colágenas é um polinômio de terceiro grau, sugerindo outras variáveis implicadas na preservação do colágeno. Conclusão: A temperatura de 73ºCelsius negativos mostrou médias percentuais de colágeno superiores em todos os períodos observados, porém à partir do 14º até o 30º dia de congelamento, a quantidade de fibras colágenas permanece estável em ambas temperaturas.

Morphological and physiological responses of apple trees under photoselective colored nets

In recent years and thanks to innovative technological advances in supplemental lighting sources and photo-selective filters, light quality manipulation (i.e. spectral composition of sunlight) have demonstrated positive effects on plant performance in ornamentals and vegetable crops. However, this aspect has been much less studied in fruit trees due to the difficulty of conditioning the light environment of orchards. The aim of the present PhD research was to study the use of different colored nets with selective light transmission in the blue (400 – 500 nm), red (600 – 700 nm) and near infrared (700 – 1100 nm) wavelengths as a tool to the light quality management and its morphological and physiological effects in field-grown apple trees. Chapter I provides a review the current status on physiological and technological advances on light quality management in fruit trees. Chapter II shows the main effect of colored nets on morpho-anatomical (stomata density, mesophyll structure and leaf mass area index) characteristics in apple leaves. Chapter III provides an analysis about the effect of micro-environmental conditions under colored nets on leaf stomatal conductance and leaf photosynthetic capacity. Chapter IV describes a study approach to evaluate the impact of colored nets on fruit growth potential in apples. Summing up results obtained in the present PhD dissertation clearly demonstrate that light quality management through photo-selective colored nets presents an interesting potential for the manipulation of plant morphological and physiological traits in apple trees. Cover orchards with colored nets might be and alternative technology to address many of the most important challenges of modern fruit growing, such as: the need for the efficient use of natural resources (water, soil and nutrients) the reduction of environmental impacts and the mitigation of possible negative effects of global climate change.

q-Hook length formulas for colored labeled forests

The major index has been deeply studied from the early 1900s and recently has been generalized in different directions, such as the case of labeled forests and colored permutations. In this thesis we define new types of labelings for forests in which the labels are colored integers. We extend the definition of the flag-major index for these labelings and we present an analogue of well known major index hook length formulas. Finally, this study (which has just apparently a simple combinatoric nature) allows us to show a notion of duality for two particular families of groups obtained from the product G(r,n)×G(r,m).

Early effects of carbachol on the morphology of motor endplates of mammalian skeletal muscle fibers

Long-term disturbance of the calcium homeostasis of motor endplates (MEPs) causes necrosis of muscle fibers. The onset of morphological changes in response to this disturbance, particularly in relation to the fiber type, is presently unknown. Omohyoid muscles of mice were incubated for 1-30 minutes in 0.1 mM carbachol, an acetylcholine agonist that causes an inward calcium current. In these muscles, the structural changes of the sarcomeres and the MEP sarcoplasm were evaluated at the light- and electron-microscopic level. Predominantly in type I fibers, carbachol incubation resulted in strong contractures of the sarcomeres underlying the MEPs. Owing to these contractures, the usual beret-like form of the MEP-associated sarcoplasm was deformed into a mushroom-like body. Consequently, the squeezed MEPs partially overlapped the adjacent muscle fiber segments. There are no signs of contractures below the MEPs if muscles were incubated in carbachol in calcium-free Tyrode's solution. Carbachol induced inward calcium current and produced fiber-type-specific contractures. This finding points to differences in the handling of calcium in MEPs. Possible mechanisms for these fiber-type-specific differences caused by carbachol-induced calcium entry are assessed.

A search for activation of C nociceptors by sympathetic fibers in complex regional pain syndrome

Although the term 'reflex sympathetic dystrophy' has been replaced by 'complex regional pain syndrome' (CRPS) type I, there remains a widespread presumption that the sympathetic nervous system is actively involved in mediating chronic neuropathic pain ["sympathetically maintained pain" (SMP)], even in the absence of detectable neuropathophysiology.

A Simple Visual Demonstration of Phase Diagram Concepts for an Introductory Materials Science Course Using Colored Solvents

A simple and effective demonstration to help students comprehend phase diagrams and understand phase equilibria and transformations is created using common chemical solvents available in the laboratory. Common misconceptions surrounding phase diagram operations, such as components versus phases, reversibility of phase transformations, and the lever rule are addressed. Three different binary liquid mixtures of varying compatibility create contrastive phase equilibrium cases, where colorful dyes selectively dissolved in each of corresponding phases allow for quick and unambiguous perceptions of solubility limit and phase transformations. Direct feedback and test scores from a group of students show evidence of the effectiveness of the visual and active teaching tool.

Abolishing myofibroblast arrhythmogeneicity by pharmacological ablation of α-smooth muscle actin containing stress fibers

Rationale: Myofibroblasts typically appear in the myocardium after insults to the heart like mechanical overload and infarction. Apart from contributing to fibrotic remodeling, myofibroblasts induce arrhythmogenic slow conduction and ectopic activity in cardiomyocytes after establishment of heterocellular electrotonic coupling in vitro. So far, it is not known whether α-smooth muscle actin (α-SMA) containing stress fibers, the cytoskeletal components that set myofibroblasts apart from resident fibroblasts, are essential for myofibroblasts to develop arrhythmogenic interactions with cardiomyocytes. Objective: We investigated whether pharmacological ablation of α-SMA containing stress fibers by actin-targeting drugs affects arrhythmogenic myofibroblast–cardiomyocyte cross-talk. Methods and Results: Experiments were performed with patterned growth cell cultures of neonatal rat ventricular cardiomyocytes coated with cardiac myofibroblasts. The preparations exhibited slow conduction and ectopic activity under control conditions. Exposure to actin-targeting drugs (Cytochalasin D, Latrunculin B, Jasplakinolide) for 24 hours led to disruption of α-SMA containing stress fibers. In parallel, conduction velocities increased dose-dependently to values indistinguishable from cardiomyocyte-only preparations and ectopic activity measured continuously over 24 hours was completely suppressed. Mechanistically, antiarrhythmic effects were due to myofibroblast hyperpolarization (Cytochalasin D, Latrunculin B) and disruption of heterocellular gap junctional coupling (Jasplakinolide), which caused normalization of membrane polarization of adjacent cardiomyocytes. Conclusions: The results suggest that α-SMA containing stress fibers importantly contribute to myofibroblast arrhythmogeneicity. After ablation of this cytoskeletal component, cells lose their arrhythmic effects on cardiomyocytes, even if heterocellular electrotonic coupling is sustained. The findings identify α-SMA containing stress fibers as a potential future target of antiarrhythmic therapy in hearts undergoing structural remodeling.

Endometriosis-associated nerve fibers, peritoneal fluid cytokine concentrations, and pain in endometriotic lesions from different locations

To assess the relationship between endometriotic lesions with associated nerve fibers with both pain and peritoneal fluid (PF) cytokine concentrations based on lesion location.

Effects of changes in colored light on brain and calf muscle blood concentration and oxygenation

Color light therapy is a therapeutic method in complementary medicine. In color therapy, light of two contrasting colors is often applied in a sequential order. The aim of this study was to investigate possible physiological effects, i.e., changes in the blood volume and oxygenation in the brain and calf muscle of healthy subjects who were exposed to red and blue light in sequential order. The hypothesis was that if a subject is first exposed to blue and then red light, the effect of the red light will be enhanced due to the contrastingly different characteristics of the two colors. The same was expected for blue light, if first exposing a subject to red and then to blue light. Twelve healthy volunteers (six male, six female) were measured twice on two different days by near-infrared spectroscopy during exposure to colored light. Two sequences of colored light were applied in a controlled, randomized, crossover design: first blue, then red, and vice versa. For the brain and muscle, the results showed no significant differences in blood volume and oxygenation between the two sequences, and a high interindividual physiological variability. Thus, the hypothesis had to be rejected. Comparing these data to results from a previous study, where subjects were exposed to blue and red light without sequential color changes, shows that the results of the current study appear to be similar to those of red light exposure. This may indicate that the exposure to red light was preponderant and thus effects of blue light were outweighed.