Time-lapse 3-D measurements of a glucose biosensor in multicellular spheroids by light sheet fluorescence microscopy in commercial 96-well plates

Light sheet fluorescence microscopy has previously been demonstrated on a commercially available inverted fluorescence microscope frame using the method of oblique plane microscopy (OPM). In this paper, OPM is adapted to allow time-lapse 3-D imaging of 3-D biological cultures in commercially available glass-bottomed 96-well plates using a stage-scanning OPM approach (ssOPM). Time-lapse 3-D imaging of multicellular spheroids expressing a glucose Förster resonance energy transfer (FRET) biosensor is demonstrated in 16 fields of view with image acquisition at 10 minute intervals. As a proof-of-principle, the ssOPM system is also used to acquire a dose response curve with the concentration of glucose in the culture medium being varied across 42 wells of a 96-well plate with the whole acquisition taking 9 min. The 3-D image data enable the FRET ratio to be measured as a function of distance from the surface of the spheroid. Overall, the results demonstrate the capability of the OPM system to measure spatio-temporal changes in FRET ratio in 3-D in multicellular spheroids over time in a multi-well plate format

Combining and Comparing Consumers' Stated Preference Ratings and Choice Responses

In this study we develop and test an econometric model for combining choice and preference ratings data collected from the same set of individuals.Choice data are modeled using a multinomial logit framework, while preference data are modeled using an ordered response equation.Individual heterogeneity is allowed for via random coefficients providing a link between the choice and ratings data.Parameters are estimated by Simulated Maximum Likelihood.An application of the model to consumer yoghurt choice in The Netherlands found that ratings based preference estimates differ significantly from choice based estimates, but the correlation between random coefficients driving the two is very strong.econometric models;preferences;consumer choice;maximum likelihood;JEL classifications;C35;M31

Automatization techniques for processing biomedical signals using machine learning methods

The Signal Processing Group (Department of Signal Theory and Communications, University Carlos III, Madrid, Spain) offers the expertise of its members in the automatic processing of biomedical signals. The main advantages in this technology are the decreased cost, the time saved and the increased reliability of the results. Technical cooperation for the research and development with internal and external funding is sought

Comparisons of Silver Nanoparticle Synthesis Methods by Microwave and Non-Microwave using Hydrogen Gas as a Reducing Agent

Synthesis and characterization of silver nanoparticles are of current interest. This research project describes a simple and rapid synthesis of silver nanoparticles upon reduction of Silver (I) oxide (Ag2O) by molecular hydrogen (H2) at elevated temperature (70 – 100 °C) and a pressure of \u3e 1 atmosphere by heating the aqueous mixture using a common kitchen microwave. This reaction generates naked silver colloids that contain no foreign stabilizers other than metal particles in aqueous media. Its application of an antibacterial effect was monitored by using biological cultures using the Kirby-Bauer Test

Secondary metabolism of the forest pathogen Dothistroma septosporum : a thesis presented in the partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Genetics at Massey University, Manawatu, New Zealand

Dothistroma septosporum is a fungus causing the disease Dothistroma needle blight (DNB) on more than 80 pine species in 76 countries, and causes serious economic losses. A secondary metabolite (SM) dothistromin, produced by D. septosporum, is a virulence factor required for full disease expression but is not needed for the initial formation of disease lesions. Unlike the majority of fungal SMs whose biosynthetic enzyme genes are arranged in a gene cluster, dothistromin genes are dispersed in a fragmented arrangement. Therefore, it was of interest whether D. septosporum has other SMs that are required in the disease process, as well as having SM genes that are clustered as in other fungi. Genome sequencing of D. septosporum revealed that D. septosporum has 11 SM core genes, which is fewer than in closely related species. In this project, gene cluster analyses around the SM core genes were done to assess if there are intact or other fragmented gene clusters. In addition, one of the core SM genes, DsNps3, that was highly expressed at an early stage of plant infection, was knocked out and the phenotype of this mutant was analysed. Then, evolutionary selection pressures on the SM core genes were analysed using the SM core gene sequences across 19 D. septosporum strains from around the world. Finally, phylogenetic analyses on some of the SM core genes were done to find out if these genes have functionally characterised orthologs. Analysis of the ten D. septosporum SM core genes studied in this project showed that two of them were pseudogenes, and five others had very low expression levels in planta. Three of the SM core genes showed high expression levels in planta. These three genes, DsPks1, DsPks2 and DsNps3, were key genes of interest in this project. But despite the different expression levels, evolutionary selection pressure analyses showed that all of the SM core genes apart from the pseudogenes are under negative selection, suggesting that D. septosporum might actively use most of its SMs under certain conditions. In silico predictions based on the amino acid sequences of the proteins encoded by SM core genes and gene cluster analyses showed that four of the SM core genes are predicted to produce known metabolites. These are melanin (DsPks1), cyclosporin (DsNps1), ferricrocin (DsNps2) and cyclopiazonic acid (DsHps1). Gene cluster analyses revealed that at least three of the D. septosporum SMs might be produced by fragmented gene clusters (DsPks1, DsNps1, DsNps2). This suggested that dothistromin might not be the only fragmented SM gene cluster in D. septosporum. According to phylogenetic analyses, some of the D. septosporum SM core genes have no orthologs among its class (Dothideomycetes), suggesting some of the D. septosporum SMs may be unique. One such example is the metabolite produced by DsNps3. Comparison of wild type and ΔDsNps3 D. septosporum strains showed that the ΔDsNps3 strain produces fewer spores, less hyphal surface network at an early stage of plant infection, and lower levels of fungal biomass in disease lesions compared to wild type, suggesting that the DsNps3 SM may be a virulence factor. Attempts to identify a metabolite associated with DsNps3, and to knockout another gene of key interest, DsPks2, for functional characterization were unsuccessful. Further work is required to confirm the gene clusters, characterise the SMs and their roles. However, the findings so far suggest that dothistromin is unlikely to be the only D. septosporum SM that is a virulence factor in since the DsNps3 SM also appears to be involved in virulence. Likewise the fragmented dothistromin cluster may not be the only one in the genome and there may be at least three more fragmented SM gene clusters

Biological patterns: Novel indicators for pharmacological assays

Variable gravity testing using the KC-135 demonstrated clearly that biological pattern formation was definitely shown to result from gravity alone, and not from oxygen gradients in solution. Motile pattern formation of spermatozoa are driven by alternate mechanisms, and apparently not affected by short-term changes in gravity. The chemical effects found appear to be secondary to the primary effect of gravity. Cryopreservation may be the remedy to the problem of 'spare' or 'standing order' biological samples for testing of space lab investigations, but further studies are necessary

Indwelling pleural catheters for non-malignant pleural effusions: report on a single centre's 10 years of experience

BACKGROUND: Recurrent pleural effusion is a common cause of dyspnoea, cough and chest pain during the course of infectious pleurisy and non-malignant diseases like congestive heart failure (CHF) or liver cirrhosis with hepatic hydrothorax (HH). With regard to the chronic character of the underlying diseases, indwelling pleural catheters (IPC) are increasingly used, not only assuring immediate symptom relief but also potentially leading to pleurodesis without sclerosing agents. PATIENTS AND METHODS: In this single-centre retrospective observational study, patient characteristics, procedural variables and outcome in patients with IPC in non-malignant pleural effusion (NMPE) were evaluated and prognostic factors for pleurodesis were identified. RESULTS: From 2006 to 2017, 54 patients received 62 IPC, of whom 48.4% with CHF and 43.5% with HH. The median length of insertion was 1.5 months (IQR 0.6-2.9 months), the median survival time after insertion 3.2 months (IQR 1.1-16.0). An adequate symptom relief was achieved in 93.2% with no need for subsequent interventions. In patients surviving ≥30 days after IPC insertion, pleurodesis was observed in 45.9%, being associated to age (<55 years, p=0.02), the primary diagnosis (p=0.03) and interventions for the underlying disease (p<0.001). Complications occurred in 24.2% of all procedures (n=15), the majority concerning mechanical obstructions (n=10) and infections (n=4). Patients with HH had an excess risk for complications (37.3%). CONCLUSION: Efficacy in symptom relief and a generally manageable safety profile recommend IPC as a first-line treatment option in NMPE, where disease-specific treatments are exhausted. Caution is warranted in patients with HH due to an excess risk for complications

Removal of algae from biological cultures: a challenge for electrocoagulation?

BACKGROUND In the search for novel technologies for the treatment of urban wastewater, combined anaerobic–algae membrane bioreactors have become a very interesting choice. Recovery of algae produced in these reactors has become the key point to obtain a good economic efficiency with this technology. In this work, electrocoagulation is studied as an alternative for the coarse removal of algae from a biological culture. RESULTS Results demonstrate that the electrochemical technology is a suitable technology for this purpose allowing the removal of more than 90% of the algae without modifying significantly the pH and with an operating cost below 0.04 € m−3. The same general trends are observed for applied current charge and current density supplied when aluminum or iron are used as electrodes although aluminum was much more efficient. CONCLUSIONS The dose of coagulant reagents required is very low, indicating that coagulant generated in the process is very efficiently used. The best results in terms of algae and turbidity removals are obtained operating at low current densities with aluminum electrodes. According to pH and z-potential values, insoluble metal hydroxide and anion M(OH)4− seems to be the primary coagulation species involved in the electrocoagulation process.ANTECEDENTES En la búsqueda de nuevas tecnologías para el tratamiento de aguas residuales urbanas, los biorreactores combinados anaerobios-membrana de algas se han convertido en una opción muy interesante. La recuperación de las algas producidas en estos reactores se ha convertido en el punto clave para obtener una buena eficiencia económica con esta tecnología. En este trabajo se estudia la electrocoagulación como alternativa para la remoción gruesa de algas de un cultivo biológico. RESULTADOS Los resultados demuestran que la tecnología electroquímica es una tecnología adecuada para este fin permitiendo eliminar más del 90% de las algas sin modificar significativamente el pH y con un coste operativo inferior a 0,04 € m −3 . Se observan las mismas tendencias generales para la carga de corriente aplicada y la densidad de corriente suministrada cuando se usan aluminio o hierro como electrodos, aunque el aluminio fue mucho más eficiente. CONCLUSIONES La dosis de reactivos coagulantes requerida es muy baja, lo que indica que el coagulante generado en el proceso se utiliza de manera muy eficiente. Los mejores resultados en términos de remoción de algas y turbidez se obtienen operando a bajas densidades de corriente con electrodos de aluminio. De acuerdo con los valores de pH y potencial z, el hidróxido de metal insoluble y el anión M(OH) 4− parecen ser las principales especies de coagulación involucradas en el proceso de electrocoagulación

Low pH, high salinity: too much for Microbial Fuel Cells?

Twelve single chambered, air-cathode Tubular Microbial Fuel Cells (TMFCs) have been filled up with fruit and vegetable residues. The anodes were realized by means of a carbon fiber brush, while the cathodes were realized through a graphite-based porous ceramic disk with Nafion membranes (117 Dupont). The performances in terms of polarization curves and power production were assessed according to different operating conditions: percentage of solid substrate water dilution, adoption of freshwater and a 35mg/L NaCl water solution and, finally, the effect of an initial potentiostatic growth. All TMFCs operated at low pH (pH$=3.0 \pm 0.5$), as no pH amendment was carried out. Despite the harsh environmental conditions, our TMFCs showed a Power Density (PD) ranging from 20 to 55~mW/m$^2 \cdot$kg$_{\text{waste}}$ and a maximum CD of 20~mA/m$^2 \cdot$kg$_{\text{waste}}$, referred to the cathodic surface. COD removal after a $28-$day period was about $45 \%$. The remarkably low pH values as well as the fouling of Nafion membrane very likely limited TMFC performances. However, a scale-up estimation of our reactors provides interesting values in terms of power production, compared to actual anaerobic digestion plants. These results encourage further studies to characterize the graphite-based porous ceramic cathodes and to optimize the global TMFC performances, as they may provide a valid and sustainable alternative to anaerobic digestion technologies.Comment: 13 pages, 10 Figure