Porosity in ion-exchanged and acid activated clays evaluated using n-nonane pre-adsorption

The applicability of the n-nonane pre-adsorption method for characterising the porosity in clays is presented. Na-SD, a Na+-exchanged purified bentonite, and materials obtained by Al3+-exchange and acid treatments of Na-SD and SAz-1 were used. Nitrogen adsorption isotherms, at -196 ºC, were determined before and after n-nonane pre-adsorption on each of the samples. In all materials, n-nonane remained adsorbed in ultramicropores after outgassing at 25 ºC. Outgassing at higher temperatures (50, 75 and 200 ºC) removed nonane and ultramicropores became available for nitrogen adsorption. All treatments on Na-SD led to increase in micropore volume. Larger ultramicropore and supermicropore volumes were obtained for Na-SD acid activated with HCl at 95 ºC than for treatments at 25 ºC with HCl or following Al3+-exchange (Al-SD), and increased with increasing acid concentration to 3 M. Activation with 4 M HCl led to the largest pore volume with contribution from mesopores. However, the specific external surface area was the same as that obtained for Na-SD, Al-SD and for most of the other acid activated samples. Treatments at 95 ºC with 1 M and 6 M HCl promoted increase in specific external surface area. The micropore volumes and specific external surface area for SAz-1 treated with 1 M HCl at 95 ºC were larger than those of Al-SAz-1, but lower than those obtained for corresponding materials derived from Na-SD. The n-nonane pre-adsorption method enabled micropore volumes and specific external surface areas to be obtained for all samples.

Microstructural-based approach to the interpretation of clays and transitional soils behaviour

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.

Densities, viscosities and derived thermophysical properties of water-saturated imidazolium-based ionic liquids

In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water-saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15 to 363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide-based compounds: the symmetric [C n C n im][NTf2] (with n = 1-8 and 10) and asymmetric [C n C1im][NTf2] (with n = 2-5, 7, 9 and 11) ILs. For water-saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water-saturated ILs, further confirming that for the ILs investigated the volumetric mixing properties of ILs and water follow a near ideal behaviour. The water-saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water-saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier.

Linear and nonlinear thermal instability of Newtonian and non-Newtonian fluid saturated porous media

The present work aims to investigate the influence of different aspects, such as non-standard steady solutions, complex fluid rheologies and non-standard porous-channel geometries, on the stability of a Darcy-Bénard system. In order to do so, both linear and nonlinear stability theories are considered. A linear analysis focuses on studying the dynamics of the single disturbance wave present in the system, while its nonlinear counterpart takes into consideration the interactions among the single modes. The scope of the stability analysis is to obtain information regarding the transition from an equilibrium solution to another one, and also information regarding the transition nature and the emergent solution after the transition. The disturbance governing equations are solved analytically, whenever possible, and numerical by considering different approaches. Among other important results, it is found that a cylinder cross-section does not affect the thermal instability threshold, but just the linear pattern selection for dilatant and pseudoplastic fluid saturated porous media. A new rheological model is proposed as a solution for singular issues involving the power-law model. Also, a generalised class of one parameter basic solutions is proposed as an alternative description of the isoflux Darcy--Bénard problem. Its stability is investigated.

Fatty Acid Synthase Inhibitors Induce Apoptosis In Non-tumorigenic Melan-a Cells Associated With Inhibition Of Mitochondrial Respiration.

The metabolic enzyme fatty acid synthase (FASN) is responsible for the endogenous synthesis of palmitate, a saturated long-chain fatty acid. In contrast to most normal tissues, a variety of human cancers overexpress FASN. One such cancer is cutaneous melanoma, in which the level of FASN expression is associated with tumor invasion and poor prognosis. We previously reported that two FASN inhibitors, cerulenin and orlistat, induce apoptosis in B16-F10 mouse melanoma cells via the intrinsic apoptosis pathway. Here, we investigated the effects of these inhibitors on non-tumorigenic melan-a cells. Cerulenin and orlistat treatments were found to induce apoptosis and decrease cell proliferation, in addition to inducing the release of mitochondrial cytochrome c and activating caspases-9 and -3. Transfection with FASN siRNA did not result in apoptosis. Mass spectrometry analysis demonstrated that treatment with the FASN inhibitors did not alter either the mitochondrial free fatty acid content or composition. This result suggests that cerulenin- and orlistat-induced apoptosis events are independent of FASN inhibition. Analysis of the energy-linked functions of melan-a mitochondria demonstrated the inhibition of respiration, followed by a significant decrease in mitochondrial membrane potential (ΔΨm) and the stimulation of superoxide anion generation. The inhibition of NADH-linked substrate oxidation was approximately 40% and 61% for cerulenin and orlistat treatments, respectively, and the inhibition of succinate oxidation was approximately 46% and 52%, respectively. In contrast, no significant inhibition occurred when respiration was supported by the complex IV substrate N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). The protection conferred by the free radical scavenger N-acetyl-cysteine indicates that the FASN inhibitors induced apoptosis through an oxidative stress-associated mechanism. In combination, the present results demonstrate that cerulenin and orlistat induce apoptosis in non-tumorigenic cells via mitochondrial dysfunction, independent of FASN inhibition.

Obesity Versus Osteoarthritis: Beyond The Mechanical Overload.

Obesity is currently considered a major public health problem in the world, already reaching epidemic characteristics, according to the World Health Organization. Excess weight is the major risk factor associated with various diseases, such as type 2 diabetes mellitus, hypertension, dyslipidemia and osteometabolic diseases, including osteoporosis and osteoarthritis. Osteoarthritis is the most prevalent rheumatic disease and the leading cause of physical disability and reduced quality of life of the population over 65 years. It mainly involves the joints that bear weight - knees and hips. However, along with the cases of obesity, its prevalence is increasing, and even in other joints, such as hands. Thus, it is assumed that the influence of obesity on the development of OA is beyond mechanical overload. The purpose of this review was to correlate the possible mechanisms underlying the genesis and development of these two diseases. Increased fat mass is directly proportional to excessive consumption of saturated fatty acids, responsible for systemic low-grade inflammation condition and insulin and leptin resistance. At high levels, leptin assumes inflammatory characteristics and acts in the articular cartilage, triggering the inflammatory process and changing homeostasis this tissue with consequent degeneration. We conclude that obesity is a risk factor for osteoarthritis and that physical activity and changes in diet composition can reverse the inflammatory and leptin resistance, reducing progression or preventing the onset of osteoarthritis.

Not Simply A Matter Of Fish Intake.

Background and aims: Recent findings have highlighted enhanced fish consumption as a potential measure to increase intake of healthy fatty acids, particularly omega-3. The generalizability of this recommendation, however, may fall short by differences in fish species and cooking techniques. Hence, we investigated how these 2 variables affect the lipid content in fish flesh. Methods and Results: Nine species of freshwater, deep sea or shore fish were grilled, steamed or fried with or without the addition of soybean oil, olive oil or butter. The lipid composition was analysed and a significant difference was observed in cholesterol, saturated fatty acids, polyunsaturated fatty acids, omega-3 fatty acids, and omega-6 fatty acids contents between species (p<0.05). The use of soybean or olive oil was associated with a significant change in flesh concentration of polyunsaturated, omega-3 and omega-6 fatty acids (p<0.05). Conclusion: This study calls attention to the specific lipid content that must be expected from different fish species and cooking techniques.

Mechanisms Of Insulin Resistance In The Amygdala: Influences On Food Intake.

Obesity is increasing worldwide and is triggered, at least in part, by enhanced caloric intake. Food intake is regulated by a complex mechanism involving the hypothalamus and hindbrain circuitries. However, evidences have showing that reward systems are also important in regulating feeding behavior. In this context, amygdala is considered a key extra-hypothalamic area regulating feeding behavior in human beings and rodents. This review focuses on the regulation of food intake by amygdala and the mechanisms of insulin resistance in this brain area. Similar to the hypothalamus the anorexigenic effect of insulin is mediated via PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B) pathway in the amygdala. Insulin decreases NPY (neuropeptide Y) and increases oxytocin mRNA levels in the amygdala. High fat diet and saturated fatty acids induce inflammation, ER (endoplasmic reticulum) stress and the activation of serine kinases such as PKCθ (protein kinase C theta), JNK (c-Jun N-terminal kinase) and IKKβ (inhibitor of nuclear factor kappa-B kinase beta) in the amygdala, which have an important role in insulin resistance in this brain region. Overexpressed PKCθ in the CeA (central nucleus of amygdala) of rats increases weight gain, food intake, insulin resistance and hepatic triglycerides content. The inhibition of ER stress ameliorates insulin action/signaling, increases oxytocin and decreases NPY gene expression in the amygdala of high fat feeding rodents. Those data suggest that PKCθ and ER stress are main mechanisms of insulin resistance in the amygdala of obese rats and play an important role regulating feeding behavior.

Enzymatic Biodiesel Synthesis From Yeast Oil Using Immobilized Recombinant Rhizopus Oryzae Lipase.

The recombinant Rhizopus oryzae lipase (1-3 positional selective), immobilized on Relizyme OD403, has been applied to the production of biodiesel using single cell oil from Candida sp. LEB-M3 growing on glycerol from biodiesel process. The composition of microbial oil is quite similar in terms of saponifiable lipids than olive oil, although with a higher amount of saturated fatty acids. The reaction was carried out in a solvent system, and n-hexane showed the best performance in terms of yield and easy recovery. The strategy selected for acyl acceptor addition was a stepwise methanol addition using crude and neutralized single cell oil, olive oil and oleic acid as substrates. A FAMEs yield of 40.6% was obtained with microbial oils lower than olive oil 54.3%. Finally in terms of stability, only a lost about 30% after 6 reutilizations were achieved.

Ecomateriais: desenvolvimento e aplicação de materiais porosos funcionais para proteção ambiental

Fundamental aspects of the conception and applications of ecomaterials, in particular porous materials in the perspective of green chemistry are discussed in this paper. General recommendations for description and classification of porous materials are reviewed briefly. By way of illustration, some case studies of materials design and applications in pollution detection and remediation are described. It is shown here how different materials developed by our groups, such as porous glasses, ecomaterials from biomass and anionic clays were programmed to perform specific functions. A discussion of the present and future of ecomaterials in green chemistry is presented along with important key goals.

Germinação e crescimento de Calophyllum brasiliense (Clusiaceae), uma espécie típica de florestas inundadas

Soil waterlogging and the subsequent reduction in the amount of oxygen available for the respiration of the root system selected, along the evolutive process, plants able to thrive in seasonally or permanently flooded areas. In neotropical plants there are many types of adaptations to flooding. In this paper we present the results of the work carried out with seeds and seedlings of C brasiliense subjected to hypoxia during germination and early development. C brasiliense seeds are not photoblastic and survive up to three months burried in a water saturated substrate, but germination only takes place in well-drained soils. Soil waterlogging does not inhibit seedling growth and there are no apparent morphological changes of the aerial part of flooded plants. New and aerated roots that make plant survival possible replace old and spoiled roots. In contrast to many typical species of flood-prone areas where growth is inhibited by oxygen stress. C. brasiliense seedlings seem to be well adapted to their waterlogged environment. Seed dispersion, the absence of photoblastic response as well as seed and seedling capacity of surviving and growing in waterlogged soils contribute to the wide geographic distribution of C. brasiliense always associated with areas subjected to soil waterlogging.

Atributos mecânicos e erosão por salpicamento em amostras de latossolo vermelho-amarelo sob efeito de vinhaça

The objective of this study was to quantify the effect of plonk on compressive behavior and mechanical attributes such as consistency, optimum moisture for compaction and maximum density of a Red-Yellow Latosol (Oxisol) to evaluate the effect of plonk and compaction state in splashed particles, from Lavras (MG) region. The plonk was obtained from an artisanal sugarcane brandy alembic. Undisturbed and disturbed soil samples were collected at 0 to 3 cm and 60 to 63 cm depths. Disturbed soil samples were used for soil characterization, determination of consistence limits and Normal Proctor essay after material incubation with plonk. Undisturbed soil samples were saturated with plonk or distilled water (control) during 48 hours for testing the compressibility and resistance to splash by using simulated rainfall. The plonk altered the consistence limits of studied layers. For the 0-3 cm layer, the plonk reduced the friable range, and for the 60-63 cm layer the effect was in the opposite direction. For both layers, the plonk increased Dmax and decreased Uoptimum. Regardless of the plonk treatment, both layers presented the same load support capacity. The compaction degree of samples influenced the splash erosion. The increase of the applied pressure over the samples resulted in increase of splash material quantity. At the 60-63 cm layer, the plonk treatment reduced the splash material quantity by increasing the applied pressure, mainly when the samples were at field capacity.

TEOR DE CAFEÍNA EM CAFÉS BRASILEIROS

Different brands and batches of brazilian regular and instant coffee were purchased in supermarkets of Campinas? city and analysed for caffeine content. The method used involved extraction with boiling water, clarification with saturated basic acetate and determination by high performance liquid cromatography. Analysis was carried out using a Model 6000 A solvent delivery system (Waters associates), and a Model 7125 sample injector system (Reodyne, Inc.) with a 5µl sample loop. The system was also equipped with a Waters Model M440 absorbance detector set at 254 nm. A Merck ODS 5µm column (15 cm x 4.6 mm i.d.) was used to separate the caffeine. The mobile phase was methanol:water (25:75, v/v). The caffeine content varied for different brands and types of coffee and according to the beverage preparation technique. Values in the range of 0.43 to 0.85 mg/ml and 0.61 to 0.82 mg/ml were determined in regular and instant coffee, respectively.