► The yield of bio-crude form HTL of macro-algae is low (∼20 wt%). ► The HHV of bio-crude from HTL of macro-algae is high (∼36MJ/kg). ► Sugars present in the aqueous phase include mannitol and ...laminarin. ► The majority of the K and Na pass into the water phase. ► The majority of the Ca and Mg pass into the residue.
The brown macro-alga Laminaria saccharina was converted into bio-crude by hydrothermal liquefaction in a batch reactor. The influence of reactor loading, residence time, temperature and catalyst (KOH) loading was assessed. A maximum bio-crude yield of 19.3wt% was obtained with a 1:10 biomass:water ratio at 350°C and a residence time of 15min without the presence of the catalyst. The bio-crude had an HHV of 36.5MJ/kg and is similar in nature to a heavy crude oil or bitumen. The solid residue has high ash content and contains a large proportion of calcium and magnesium. The aqueous phase is rich in sugars and ammonium and contains a large proportion of potassium and sodium.
A range of model biochemical components, microalgae and cyanobacteria with different biochemical contents have been liquefied under hydrothermal conditions at 350
°C, ∼200
bar in water, 1
M Na
2CO
3 ...and 1
M formic acid. The model compounds include albumin and a soya protein, starch and glucose, the triglyceride from sunflower oil and two amino acids. Microalgae include
Chlorella vulgaris,
Nannochloropsis occulata and
Porphyridium cruentum and the cyanobacteria
Spirulina. The yields and product distribution obtained for each model compound have been used to predict the behaviour of microalgae with different biochemical composition and have been validated using microalgae and cyanobacteria. Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition. The yields of bio-crude are 5–25
wt.% higher than the lipid content of the algae depending upon biochemical composition. The yields of bio-crude follow the trend lipids
>
proteins
>
carbohydrates.
The use of gold(I) complexes as catalysts for organic transformations has become increasingly common over the past decade, leading to the development of a number of useful carbon–carbon and ...carbon–heteroatom bond‐forming processes. In contrast, enantioselective catalysis employing gold(I) complexes was, until recently, exceedingly rare, due in large part to the pronounced tendency of gold(I) to form linear, two‐coordinate complexes. However, new approaches and strategies have emerged over the past two years, leading to the development of a number of effective gold(I)‐catalyzed enantioselective transformations, most notably the enantioselective hydrofunctionalization of allenes. Outlined herein is an overview of enantioselective gold(I) catalysis since 2005.
Enantioselective catalysis employing gold(I) complexes was, until recently, exceedingly rare, due in large part to the pronounced tendency of gold(I) to form linear, two‐coordinate complexes. However, new approaches and strategies have emerged over the past two years, leading to the development of a number of effective gold(I)‐catalyzed enantioselective transformations, most notably the enantioselective hydrofunctionalization of allenes.
Excitatory afferents to the nucleus accumbens (NAc) are thought to facilitate reward seeking by encoding reward-associated cues. Selective activation of different glutamatergic inputs to the NAc can ...produce divergent physiological and behavioral responses, but mechanistic explanations for these pathway-specific effects are lacking. Here, we compared the innervation patterns and synaptic properties of ventral hippocampus, basolateral amygdala, and prefrontal cortex input to the NAc. Ventral hippocampal input was found to be uniquely localized to the medial NAc shell, where it was predominant and selectively potentiated after cocaine exposure. In vivo, bidirectional optogenetic manipulations of this pathway attenuated and enhanced cocaine-induced locomotion. Challenging the idea that any of these inputs encode motivationally neutral information, activation of each discrete pathway reinforced instrumental behaviors. Finally, direct optical activation of medium spiny neurons proved to be capable of supporting self-stimulation, demonstrating that behavioral reinforcement is an explicit consequence of strong excitatory drive to the NAc.
► Hippocampal input is predominant in the medial NAc shell and potentiated by cocaine ► Activity in hippocampal axons in the NAc drives cocaine-induced locomotion ► Irrespective of the pathway, mice work for photostimulation of glutamate axons in NAc ► Mice work to obtain direct optogenetic stimulation of NAc shell neurons
Britt et al. characterize hippocampal, amygdala, and prefrontal cortex input to the nucleus accumbens. Hippocampal input is shown to be predominant in the medial accumbens shell, yet photostimulation of axons from each pathway is sufficient to reinforce instrumental behaviors.
The active metabolite of vitamin A, retinoic acid (RA), is a powerful regulator of gene transcription. RA is also a therapeutic drug. The oxidative metabolism of RA by certain members of the ...cytochrome P450 (CYP) superfamily helps to maintain tissue RA concentrations within appropriate bounds. The CYP26 family--CYP26A1, CYP26B1, and CYP26C1--is distinguished by being both regulated by and active toward all-trans-RA (at-RA) while being expressed in different tissue-specific patterns. The CYP26A1 gene is regulated by multiple RA response elements. CYP26A1 is essential for embryonic development, whereas CYP26B1 is essential for postnatal survival as well as germ cell development. Enzyme kinetic studies have demonstrated that several CYP proteins are capable of metabolizing at-RA; however, it is likely that CYP26A1 plays a major role in RA clearance. Thus, pharmacological approaches to limiting the activity of CYP26 enzymes may extend the half-life of RA and could be useful clinically in the future.
Interest in vitamin A as a regulator of immune function goes back to the early 1900s. Recently, several lines of evidence have converged to show that retinoic acid (RA), a major oxidative metabolite ...of vitamin A, plays a key role in the differentiation of T cell subsets, the migration of T cells into tissues, and the proper development of T cell–dependent antibody responses. This review discusses evidence from experimental studies that RA promotes the differentiation of regulatory T cells, which help to suppress inflammatory reactions, and plays a significant role in normal mucosal immunity by modulating T cell activation and regulating cell trafficking. RA also promotes antibody responses to T cell–dependent antigens. Conversely, in a state of vitamin A deficiency, inflammatory T cell reactions may be inadequately opposed and therefore become dominant. Although data from human studies are still needed, the framework now developed from studies in mice and rat models suggests that adequate vitamin A status, whether derived from ingestion of preformed retinol or β-carotene, is important for maintaining a proper balance of well-regulated T cell functions and for preventing excessive or prolonged inflammatory reactions.
Inflammation has a major impact on iron homeostasis. This review focuses on acute and chronic inflammation as it affects iron trafficking and, as a result, the availability of this essential ...micronutrient to the host. In situations of microbial infection, not only the host is affected but also the offending microorganisms, which, in general, not only require iron for their own growth but have evolved mechanisms to obtain it from the infected host. Key players in mammalian iron trafficking include several types of cells important to iron acquisition, homeostasis, and hematopoiesis (enterocytes, hepatocytes, macrophages, hematopoietic cells, and in the case of pregnancy, placental syncytiotrophoblast cells) and several forms of chaperone proteins, including, for nonheme iron, the transport protein transferrin and the intracellular iron-storage protein ferritin, and for heme iron, the chaperone proteins haptoglobin and hemopexin. Additional key players are the cell membrane–associated iron transporters, particularly ferroportin (FPN), the only protein known to modulate iron export from cells, and finally, the iron-regulatory hormone hepcidin, which, in addition to having antibacterial activity, regulates the functions of FPN. Interestingly, the impact of infection on iron homeostasis differs among pathogens whose mode of infection is mainly intracellular or extracellular. Understanding how inflammation affects each of these processes may be crucial for understanding how inflammation affects iron status, indicators of iron sufficiency, and iron supplementation during inflammation and how it may potentially result in a beneficial or detrimental impact on the host.
Summary Huntington's disease is a progressive, fatal, neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin gene, which encodes an abnormally long polyglutamine repeat in the ...huntingtin protein. Huntington's disease has served as a model for the study of other more common neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. These disorders all share features including: delayed onset; selective neuronal vulnerability, despite widespread expression of disease-related proteins during the whole lifetime; abnormal protein processing and aggregation; and cellular toxic effects involving both cell autonomous and cell-cell interaction mechanisms. Pathogenic pathways of Huntington's disease are beginning to be unravelled, offering targets for treatments. Additionally, predictive genetic testing and findings of neuroimaging studies show that, as in some other neurodegenerative disorders, neurodegeneration in affected individuals begins many years before onset of diagnosable signs and symptoms of Huntington's disease, and it is accompanied by subtle cognitive, motor, and psychiatric changes (so-called prodromal disease). Thus, Huntington's disease is also emerging as a model for strategies to develop therapeutic interventions, not only to slow progression of manifest disease but also to delay, or ideally prevent, its onset.
► The use of heterogeneous catalysts during HTL of microalgae results in increased de-oxygenation. ► Triglycerides decompose to fatty acids and are hydrogenated under hydrothermal conditions. ► The ...use of a Ni/Al2O3 catalyst de-oxygenates the lipids to form alkanes and promotes gasification.
Hydrothermal processing of high lipid feedstock such as microalgae is an alternative method of oil extraction which has obvious benefits for high moisture containing biomass. A range of microalgae and lipids extracted from terrestrial oil seed have been processed at 350°C, at pressures of 150–200bar in water. Hydrothermal liquefaction is shown to convert the triglycerides to fatty acids and alkanes in the presence of certain heterogeneous catalysts. This investigation has compared the composition of lipids and free fatty acids from solvent extraction to those from hydrothermal processing. The initial decomposition products include free fatty acids and glycerol, and the potential for de-oxygenation using heterogeneous catalysts has been investigated. The results indicate that the bio-crude yields from the liquefaction of microalgae were increased slightly with the use of heterogeneous catalysts but the higher heating value (HHV) and the level of de-oxygenation increased, by up to 10%.
A preliminary classification of five macroalgae from the British Isles;
Fucus vesiculosus, Chorda filum, Laminaria digitata, Fucus serratus, Laminaria hyperborea, and Macrocystis pyrifera from South ...America, has been presented in terms of a Van Krevelen diagram. The macroalgae have been characterised for proximate and ultimate analysis, inorganic content, and calorific value. The different options for thermal conversion and behaviour under combustion and pyrolysis have been evaluated and compared to several types of terrestrial biomass including
Miscanthus, short rotation Willow coppice and Oat straw. Thermal treatment of the macroalgae has been investigated using thermogravimetry (TGA) and pyrolysis-gc-ms. Combustion behaviour is investigated using TGA in an oxidising atmosphere. The suitability of macroalgae for the different thermal processing routes is discussed. Ash chemistry restricts the use of macroalgae for direct combustion and gasification. Pyrolysis produces a range of pentosans and a significant proportion of nitrogen containing compounds. High char yields are produced.
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