Biomass gasification for the production of methane

Biomass is very promising as a sustainable alternative to fossil resources because it is a renewable source that contains carbon, an essential building block for gaseous and liquid fuels. Methane is the main component of natural gas, which is a fuel used for heating, power generation and transportation. In The Netherlands, the contribution of natural gas to the primary energy consumption is almost 50% (Source: Energy Research Centre of The Netherlands [ECN]) and it is a fuel with a well-developed pipeline distribution network and infrastructure.\ud \ud There are different biomass conversion routes to methane depending on the water content of the biomass feed. The thermochemical conversion route to convert relatively dry biomass into methane is conventionally envisaged in a two-step process: In the first step, biomass is gasified (with heat demand, high T / low P) and in the second step methane is formed (with heat release, low T / high P) in a separate reactor. In this configuration there is no heat integration possible between the two process stages. \ud \ud In this thesis, a new gasification concept is investigated, termed self-gasification, that overcomes, inter alia, the issue of heat integration. The concept entails an intermediate temperature (700-800°C) and pressure (25-35 bar) steam gasifier, where recycled ash components -contained in the biomass itself- serve as potential “catalysts” for char (from biomass pyrolysis) gasification, methane formation, gas conditioning and tar cracking. The focus of the present research lies on process evaluation and study of the influence of biomass ashes on the aforementioned reactions. Ashes are present in different concentrations in targeted biomass feeds for gasification; ranging from ~0.5 wt.% in “clean wood” to ~15 wt.% in chicken litter. For that reason alone, results presented in this thesis are not limited to the self-gasification concept where methane is the final product, but give valuable information for other biomass gasification processes as well. Subjects such as gasification under pressure, methane formation and the effect of naturally occurring ash in biomass are dealt with in this thesis.\ud \ud The concept is now ready to be studied in an integrated bench-scale unit for further evaluation

Viral delivery of antioxidant genes as a therapeutic strategy in experimental models of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with no effective treatment to date. Despite its multi-factorial aetiology, oxidative stress is hypothesized to be one of the key pathogenic mechanisms. It is thus proposed that manipulation of the expression of antioxidant genes that are downregulated in the presence of mutant SOD1 may serve as a therapeutic strategy for motor neuronal protection. Lentiviral vectors expressing either PRDX3 or NRF2 genes were tested in the motor neuronal-like NSC34 cell line, and in the ALS tissue culture model, NSC34 cells expressing the human SOD1(G93A) mutation. The NSC34 SOD1(G93A) cells overexpressing either PRDX3 or NRF2 showed a significant decrease in endogenous oxidation stress levels by 40 and 50% respectively compared with controls, whereas cell survival was increased by 30% in both cases. The neuroprotective potential of those two genes was further investigated in vivo in the SOD1(G93A) ALS mouse model, by administering intramuscular injections of adenoassociated virus serotype 6 (AAV6) expressing either of the target genes at a presymptomatic stage. Despite the absence of a significant effect in survival, disease onset or progression, which can be explained by the inefficient viral delivery, the promising in vitro data suggest that a more widespread CNS delivery is needed

Neuroprotective impact of Ximenia americana aqueous bark extract on Diazepam-induced memory impairment in mice via its antioxidant potential

In traditional medicine, Ximenia americana (XA) is used to treat mental disorders, and headaches. The current study aimed to show the preventive and biochemical impacts of XA aqueou’s extract on diazepam-induced amnesia. Mice were randomized as follows: distilled water (10 mL/kg); diazepam (3 mg/kg); piracetam (PIR) (150 mg/kg); and XA experimental groups (25, 50 and 75 mg/kg). Mice were then treated in groups, 14 straight days. Radial arm maze (RAM) and T-maze were employed to assess different behaviours 30 min after each treatment. After the test was completed, the brains were isolated for histological and biochemical examinations. The results obtained showed that XA extract seriously (p < 0.001) reversed mistakes in working remembrance in the radial arm maze test contrasted to the normal control factions. In the T-maze test, pretreatment of mice with XA extract seriously (p < 0.001) expanded the time spent in the preferred arm when contrasted to the DZP-only treated faction. The XA-treated DZP groups showed subsequent (p < 0.001) improvement in catalase (CAT) and reduced glutathione (GHS). A diminish in malondialdehyde (MDA) level was observed in brain homogenates of mice treated with the extract contrasted with the DZP- group. These few results regarding the neuroprotective and antioxidant effects of XA extract at least partially demonstrate its empirical use in the treatment of certain pathologies

Image analysis technique as a tool to identify morphological changes in Trametes versicolor pellets according to exopolysaccharide or laccase production

Image analysis technique was applied to identify morphological changes of pellets from white-rot fungus Trametes versicolor on agitated submerged cultures during the production of exopolysaccharide (EPS) or ligninolytic enzymes. Batch tests with four different experimental conditions were carried out. Two different culture media were used, namely yeast medium or Trametes defined medium and the addition of lignolytic inducers as xylidine or pulp and paper industrial effluent were evaluated. Laccase activity, EPS production, and final biomass contents were determined for batch assays and the pellets morphology was assessed by image analysis techniques. The obtained data allowed establishing the choice of the metabolic pathways according to the experimental conditions, either for laccase enzymatic production in the Trametes defined medium, or for EPS production in the rich Yeast Medium experiments. Furthermore, the image processing and analysis methodology allowed for a better comprehension of the physiological phenomena with respect to the corresponding pellets morphological stages.The authors acknowledge Portucel-Empresa de Celulose e Papel, Cacia, Portugal, SA for the pulp and paper Kraft effluent used in this work. This work was funded by FEDER Funds through the Programa Operacional Factores de Competitividade-COMPETE, and national funds through FCT-Fundacao para a Ciencia e a Tecnologia under the projects PEst-C/CTM/LA/0011/2013 and PEst-C/EQB/LA0020/2013. A. P. M. Tavares acknowledge the financial support of (Programme Ciencia 2008) FCT, Portugal

Cancer-ID:Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1μm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Self-sustained activity of low firing rate in balanced networks

Self-sustained activity in the brain is observed in the absence of external stimuli and contributes to signal propagation, neural coding, and dynamic stability. It also plays an important role in cognitive processes. In this work, by means of studying intracellular recordings from CA1 neurons in rats and results from numerical simulations, we demonstrate that self-sustained activity presents high variability of patterns, such as low neural firing rates and activity in the form of small-bursts in distinct neurons. In our numerical simulations, we consider random networks composed of coupled, adaptive exponential integrate-and-fire neurons. The neural dynamics in the random networks simulates regular spiking (excitatory) and fast spiking (inhibitory) neurons. We show that both the connection probability and network size are fundamental properties that give rise to self-sustained activity in qualitative agreement with our experimental results. Finally, we provide a more detailed description of self-sustained activity in terms of lifetime distributions, synaptic conductances, and synaptic currents

Circulating Tumor Cells (CTC) and Tumor-Derived Extracellular Vesicles (tdEV)

The observation that increasing circulating tumor cell (CTC) and tumor-derived extracellular vesicle (tdEV) load is directly related to worse clinical outcome of cancer patients is in line with expectations. However, both CTC and tdEV exhibit inter- and intra-patient heterogeneity, and the puzzle is yet to be deciphered in regard to the phenotype of CTC or tdEV that can predict prognosis and response to therapy or an effective treatment. A large variety of different approaches to identify CTC and tdEV have emerged over the last two decades, some of which have been evaluated in the clinic, whereas others not. In the second case, we can just speculate what is the output of these techniques and how it is translated to better understand the metastatic process and guide cancer patient care more effectively. Here, we will review what we have learned from CTC and tdEV identified by the CellSearch system and discuss our initial attempts to further characterize tdEV and explore their potential.</p

High-throughput screening technique for biomass conversion in hot compressed water

The study presented is a follow-up work regarding the quartz capillary technique which was developed in our research group for performing screening tests of different biomass conversion routes. The aspects examined are flushing of the capillary with an inert gas, diffusion of gases through the quartz reactor wall and the catalytic activity of this wall. It was shown that hydrogen diffuses through the quartz reactor wall, which shows slight catalytic activity. This has, however, a negligible effect on previously obtained results for reactions at 250–800 °C up to 60 min reaction time. Flushing of the capillary microreactor with N2 prior to sealing and reaction is essential, especially for low organics concentrations, to avoid partial product combustion by atmospheric O2 in the capillary