Nanoporous Carbon Synthesis: An Old Story with Exciting New Chapters

Activated carbons are key materials in technological applications of multidisciplinary fields (e.g. adsorption, separation, and catalytic processes). The extensive use of these materials results from the combination of a well-developed pore network (micropores or micro + mesopores) along with the presence of heteroatoms (e.g. oxygen, nitrogen, and sulfur). The large scale production of nanoporous carbons is a well-established process since the first patents date from the beginning of the twentieth century. Conventional activation methodologies are divided between physical, using steam or CO2, and chemical, being KOH, ZnCl2, and H3PO4 the most commonly reported oxidizing agents. Due to the panoply of operational parameters that can be changed or added in the production of activated carbons, there is still room for R&D. In this chapter, both conventional and innovative synthetic processes are reviewed to offer an up-to-date picture regarding raw materials, carbonization step, activation process, and other approaches. Conventional activation of gels and chars obtained by novel approaches (i.e. sol-gel method, hydrothermal carbonization (HTC), and acid-mediated carbonization) and more innovative strategies (i.e. variations of HTC process, carbonization of organic salts and ionothermal approaches) are addressed. Textural, surface chemistry and morphological properties of the derived porous carbons were reviewed and critically rationalized

Factors impacting the microbial production of eicosapentaenoic acid

The increasing applications for eicosapentaenoic acid (EPA) and the potential shortfall in supply due to sustainability and contamination issues related with its conventional sources (i.e., fish oils; seafood) led to an extensive search for alternative and sustainable sources, as well as production processes. The present mini-review covers all the steps involved in the production of EPA from microorganisms, with a deeper focus on microalgae. From production systems to downstream processing, the most important achievements within each area are briefly highlighted. Comparative tables of methodologies are also provided, as well as additional references of recent reviews, so that readers may deepen their knowledge in the different issues addressed. Key points: • Microorganisms are more sustainable alternative sources of EPA than fish. • Due to the costly separation from DHA, species that produce only EPA are preferable. • EPA production can be optimised using non-genetic and genetic tailoring engineering.info:eu-repo/semantics/publishedVersio

Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures

Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizuremouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.Foundation for Science and Technology (FCT, Portugal); COMPETE; FEDER [PTDC/SAU-NEU/102612/2008, PTDC/NEU-OSD/0473/2012, PEst-C/SAU/LA0001/2013-2014, PEst-OE/EQB/LA0023/2013-2014]; FCT, Portugal [SFRH/BPD/78901/2011, SFRH/BD/77903/2011

Removal Processes of Pharmaceuticals in Constructed Wetlands

Over the latest years the occurrence of pharmaceutical residues in the environment has been motivating an increasing concern over the possible harmful effects of many of these pollutants to living organisms. In fact many reports are available in the literature about the detection of several of the most consumed pharmaceuticals, their metabolites and transformation products in wastewaters as well as surface and ground waters and even in drinking waters worldwide. This situation can be attributed to the general inadequacy of the conventional treatment processes used in wastewater treatment plants (WWTPs) in dealing with trace pollutants. The reason for the low efficiencies of conventional WWTPs for removal of pharmaceuticals is the fact that these plants were designed to remove bulk constituents of wastewater such as suspended solids, dissolved biodegradable organic matter, pathogens and nutrients and not for also dealing with trace pollutants in general. Due to the highly variable physical and chemical properties of these organic compounds, the efficiencies by which they are removed may vary substantially. Despite the low concentration levels at which pharmaceuticals are generally present in the environment, there is a significant potential for synergistic effects between compounds with similar modes of action or related therapeutic targets, which is enough to be of serious concern. Therefore, there is an urgent need to find ways of retaining and removing these pollutants before they reach the receiving water bodies. Optimization of the WWTP processes has been tried by increasing hydraulic and solid retention times, for example. In addition, some advanced technologies have been evaluated to decrease their discharge into water bodies. However, despite the sometimes high removal efficiencies attained, these processes are generally not cost-effective on a large scale. In fact, it remains a crucial necessity to find applicable technologies for removing pharmaceuticals from wastewater with higher efficiencies at reasonable cost of operation and maintenance. Constructed wetlands systems (CWS) are being increasingly used as an option to remove micropollutants, in particular organic xenobiotic compounds, from wastewaters. There is a vast range of studies highlighting the high efficiencies of these systems in removing a wide variety of compound types, including some pharmaceuticals. For this reason, this type of systems are being adopted as a tertiary treatment option in domestic wastewater treatment and, also, at least as part of the specialized wastewater treatment plants of some industries (such as chemical, dye, tannery, livestock, etc.). Often CWS have been studied under a “black box” approach where only influent and effluent pollutants concentrations were assessed and no further in-depth investigations were pursued. However, in order to use CWS as a more efficient response to new challenges such as those presented by the more recalcitrant micropollutants, a thorough characterization of the processes involved in pollutants removal in CWS is direly needed, as well as some understanding of the ways the several CWS components (solid matrix, vegetation and microorganisms) may interact with each other synergistically. This, in fact, has been an effort which increasingly has been undertaken in the most recent years as a new trend in CWS research, not only in field studies but also in numerous lab studies as well. As result of the increases knowledge of such processes and interactions, a better guidance in the selection and optimization of the CWS components for more specific applications becomes possible. In this work we intend to present a review of the main pharmaceutical removal and transformation processes in CWS, the roles played by the most important components of CWS in such processes and how the overall treatment system performance is affected by all these. Some attention will be given to the most recent studies published on this subject, especially those involving specific CWS application for the removal of pharmaceuticals and which focus on the characterization/optimization of processes or the selection of CWS components. Some of the questions remaining to be addressed about the removal mechanisms in CWS and the aspects of CWS operation that still require optimization will also be highlighted in this work

Optimization of ω-3 fatty acid production by microalgae: Crossover effects of CO2 and light intensity under batch and continuous cultivation modes

The microalga Pavlova lutheri is a potential source of economically valuable docosahexaenoic and eicosapentaenoic acids. Specific chemical and physical culture conditions may enhance their biochemical synthesis. There are studies relating the effect of CO2 on growth; however, this parameter should not be assessed independently, as its effect strongly depends on the light intensity available. In this research, the combined effects of light intensity and CO2 content on growth and fatty acid profile in P. lutheri were ascertained, in order to optimize polyunsaturated fatty acid production. The influence of the operation mode was also tested via growing the cultures by batch and by continuous cultivation. Higher light intensities associated with lower dilution rates promoted increases in both cell population and weight per cell. Increased levels of CO2 favored the total lipid content, but decreased the amounts of polyunsaturated fatty acids. Mass productivities of eicosapentaenoic acid (3.61 ± 0.04 mg . L⁻¹ . d⁻¹) and docosahexaenoic acid (1.29 ± 0.01 mg . L⁻¹. d⁻¹) were obtained in cultures supplied with 0.5% (v/v) CO2, at a dilution rate of 0.297 d)1 and a light intensity of 120 µE . m-2 . s-1

Why nature has elected Michaelis-Menten kinetics for enzymes: a tentative rationale from variational calculus

The kinetic performance of enzymes, the catalysts designed by nature to accelerate the chemical reactions that support life, has traditionally been described in terms of a rate expression first derived by Michaelis and Menten in the beginning of this century. Why nature has selected such kinetic behaviour remains, however, a mystery. A tentative rationale based on Euler's equation was developed and, after having eliminated functional forms due to physico-chemical unfeasibility, a final open-form objective function (written as an infinite series and including dependencies on the substrate concentration, on the reaction rate, and on the derivative thereof with respect to concentration) is found. The integral of such an objective function is maximized by Michaelis-Menten kinetics and yields its maximum value when the upper integration limit is roughly equal to the Michaelis-Menten constant

Kinetic modeling of the autotrophic growth of pavlova lutheri: Study of the combined influence of light and temperature

The optimization and control of biochemical processes require the previous establishment of mathematical models that can describe the effect of process variables on their actual kinetics. Environmental temperature is a modulating factor to which the algal cells respond continuously by adjusting their rates of cellular reactions, their nutritional requirements, and, consequently, their biomass composition. Light intensity is an exhaustible resource, indispensable to autotrophic organisms. The effects of light intensity and temperature on growth of the microalga Pavlova lutheri, which have hardly been considered to date in a simultaneous fashion, were experimentally assessed using a factorial experimental design; in this way, the effects of each variable independently and their interactions could be quantified, using maximum biomass (Xmax) or maximum specific growth rate (μmax) as objective functions. The preliminary results produced indicated that light intensity plays a more important role on μmax than temperature; in the case of Xmax, both temperature and, to a lesser extent, light intensity do apparently play a role. The highest values of Xmax were associated with low temperatures and high light intensities; a similar behavior could be observed for μmax concerning light intensity, although the dependency on temperature did not seem to be as important. A more complex mechanistic model was then postulated, incorporating light and temperature as input variables, which was successfully fitted to the experimental data generated during batch cultivation of P. lutheri.info:eu-repo/semantics/acceptedVersio

Brand gender and consumer-based brand equity on Facebook: The mediating role of consumer-brand engagement and brand love

Brand gender has been suggested as a relevant source of consumer-based brand equity (CBBE). The purpose of this paper is to deepen understanding of the relationship between brand gender and CBBE by analyzing the mediating roleofconsumer–brandengagement (CBE)andbrandlove(BL)onthisrelationship.Thisresearchwas conducted on Facebook, the dominant global social media platform. The hypotheses were tested using structural equation modeling. Results support 6 of the 9 hypotheses, with a significant relationship between analyzed constructs. This study advances prior work by showing that brand gender has an indirect and relevant impact on CBBE through BL and CBE. Therefore, this research confirms the advantages of clear gender positioning and extends prior research by suggesting that brands with a strong gender identity will encourage BL and CB

Pilot-scale study on the removal of pharmaceuticals by LECA based SSF-constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Some compounds are just resistant to degradation in the sewage treatment plants (STPs) while others, although suffering partial degradation, still end up in receiving water bodies due to the large inputs received in STPs [1]. Clofibric acid (a metabolite from a series of widely used blood lipids lowering agents), ibuprofen (an anti-inflamatory non-prescription drug) and carbamazepine (an anticonvulsant and mood stabilizing drug) are some of the most frequently found PhACs in environmental monitoring studies [1]. Wastewater treatment by sub-surface flow constructed wetland systems (SSF-CWs) is a low-cost technology that has shown some capacity for removal of several organic xenobiotic pollutants, but fewer studies exist on pharmaceuticals behavior. The aim of the present work was to evaluate the efficiency of a pilot SSF-CW assembled with the plants cattail (Typha spp.) and a clay material (LECA 2/4) as support matrix, for the removal of three pharmaceuticals, namely ibuprofen (IB), carbamazepine (CB) and clofibric acid (CA), from contaminated wastewaters. Four beds were planted with pre-grown cattails (density of 80 plants/m2) and four were left unplanted to be used as controls. Experiments were conducted both in batch and in continuous mode with a flooding rate of 100%. Pharmaceutical concentrations were quantified by HPLC with UV detection at 210 nm (CB), 222 nm (IB) and 230 nm (CA). Solid phase extraction was used for sample pre-concentration whenever the measured pharmaceutical concentrations fell under the limit of quantification of the analytical method. The physico-chemical characterization of the support matrix material, LECA, involved the determination of properties such as pH, point of zero charge, electrical conductivity, apparent porosity, bulk density and hydraulic conductivity. In order to shed some light on the tolerance mechanisms developed by Typha spp. in the presence of these pharmaceuticals, biochemical and physiological parameters were evaluated. Typha spp. showed good tolerance to the presence of CA, CB and IB concentrations of 1 mg L-1, which is a value much higher than those usually reported in wastewaters. LECA alone was able to remove about 90% of the initial amounts of CB and IB in solution, and 50% of CA. IB was very susceptible to microbial degradation and up to 80% of the initial concentration could be removed by the microbial population present in the wastewater used. Overall, the CWS shows a higher removal performance for CA, CB and IB than any of its individual components (plants, support matrix, microorganisms) considered separately. CA proved to be the most resilient compound, which comes in agreement with other published data. However, this system enabled the removal of substantially higher amounts of CA than has previously been reported in other studies. The use of systems of this kind for the removal of pharmaceuticals from wastewaters seems like a promising alternative to the less efficient processes of conventional wastewater treatment

Removal of polycyclic aromatic hydrocarbons in water, using byproducts of cork industry

Os Hidrocarbonetos Aromáticos Policíclicos (HAPs) são contaminantes persistentes em meio aquoso. Estes compostos são conhecidos pelas suas propriedades carcinogénicas, mutagénicas e genotóxicas. O principal objetivo deste trabalho consistiu na avaliação das potencialidades de subprodutos da indústria corticeira, como adsorventes alternativos para a remoção de cinco HAPs em meio aquoso: benzo(a)pireno, benzo(ghi)perileno, benzo(b)fluoranteno, benzo(k)fluoranteno e indeno(1,2,3-cd)pireno. A metodologia analítica para quantificar os HAPs envolveu a preparação das amostras, através da técnica de extração em fase sólida (SPE), e a quantificação dos compostos analisados por cromatografia líquida com detetor de fluorescência (LC-FLD). O método foi otimizado e validado, obtendo-se limites de quantificação de 0,004 μg/L para todos os HAPs. Os estudos incidiram na utilização de uma amostra de cortiça, pó de aglomerado de cortiça expandida (PACE), obtida por aglutinação de cortiça em condições hidrotérmicas, a qual nos estudos preliminares revelou desempenho semelhante aos carvões ativados. Com exceção do benzo(ghi)perileno, os resultados mostram que o processo de adsorção dos HAPs na amostra PACE segue uma cinética de pseudo-segunda ordem e as isotérmicas ajustam-se ao modelo de Langmuir.Polycyclic Aromatic Hydrocarbons (PAHs) are persistent contaminants present in aqueous media. These compounds are known for their carcinogenic, mutagenic and genotoxic properties. The main objective of this work was to evaluate the potential of cork industry by-products as alternative adsorbents for the removal of five PAHs in aqueous media: benzo(a)pyrene, benzo(ghi)perylene, benzo(b)fluoranthene, benzo(k)fluoranthene e indeno( 1,2,3-cd)pyrene. The analytical methodology used to quantify PAHs consisted in the first step of sample preparation using solid phase extraction (SPE) technique, followed by quantification by liquid chromatography with a fluorescence detector (LC-FLD). The method was optimized and validated, yielding limits of quantification of 0.004 μg L-1 for all PAHs. The studies have focused on the use of a sample cork (PACE), obtained by agglutination of cork under hydrothermal conditions, which in preliminary studies attained removal efficiencies similar to those of activated carbons. With the exception of benzo(ghi)perylene, the results reveal that adsorption process of PAHs on sample PACE obey to the pseudo-second order kinetic equation and to the Langmuir model.Este trabalho foi suportado financeiramente pelo programa QREN-COMPETE, através do projeto de investigação Watercork (nº 2009/5523)