The Effect of Diel Temperature and Light Cycles on the Growth of Nannochloropsis oculata in a Photobioreactor Matrix

A matrix of photobioreactors integrated with metabolic sensors was used to examine the combined impact of light and temperature variations on the growth and physiology of the biofuel candidate microalgal species Nannochloropsis oculata. The experiments were performed with algal cultures maintained at a constant 20u C versus a 15°C to 25°C diel temperature cycle, where light intensity also followed a diel cycle with a maximum irradiance of 1920 μmol photons m-2 s-1. No differences in algal growth (Chlorophyll a) were found between the two environmental regimes; however, the metabolic processes responded differently throughout the day to the change in environmental conditions. The variable temperature treatment resulted in greater damage to photosystem II due to the combined effect of strong light and high temperature. Cellular functions responded differently to conditions before midday as opposed to the afternoon, leading to strong hysteresis in dissolved oxygen concentration, quantum yield of photosystem II and net photosynthesis. Overnight metabolism performed differently, probably as a result of the temperature impact on respiration. Our photobioreactor matrix has produced novel insights into the physiological response of Nannochloropsis oculata to simulated environmental conditions. This information can be used to predict the effectiveness of deploying Nannochloropsis oculata in similar field conditions for commercial biofuel production. © 2014 Tamburic et al

Role of protein kinase C and epidermal growth factor receptor signalling in growth stimulation by neurotensin in colon carcinoma cells

<p>Abstract</p> <p>Background</p> <p>Neurotensin has been found to promote colon carcinogenesis in rats and mice, and proliferation of human colon carcinoma cell lines, but the mechanisms involved are not clear. We have examined signalling pathways activated by neurotensin in colorectal and pancreatic carcinoma cells.</p> <p>Methods</p> <p>Colon carcinoma cell lines HCT116 and HT29 and pancreatic adenocarcinoma cell line Panc-1 were cultured and stimulated with neurotensin or epidermal growth factor (EGF). DNA synthesis was determined by incorporation of radiolabelled thymidine into DNA. Levels and phosphorylation of proteins in signalling pathways were assessed by Western blotting.</p> <p>Results</p> <p>Neurotensin stimulated the phosphorylation of both extracellular signal-regulated kinase (ERK) and Akt in all three cell lines, but apparently did so through different pathways. In Panc-1 cells, neurotensin-induced phosphorylation of ERK, but not Akt, was dependent on protein kinase C (PKC), whereas an inhibitor of the β-isoform of phosphoinositide 3-kinase (PI3K), TGX221, abolished neurotensin-induced Akt phosphorylation in these cells, and there was no evidence of EGF receptor (EGFR) transactivation. In HT29 cells, in contrast, the EGFR tyrosine kinase inhibitor gefitinib blocked neurotensin-stimulated phosphorylation of both ERK and Akt, indicating transactivation of EGFR, independently of PKC. In HCT116 cells, neurotensin induced both a PKC-dependent phosphorylation of ERK and a metalloproteinase-mediated transactivation of EGFR that was associated with a gefitinib-sensitive phosphorylation of the downstream adaptor protein Shc. The activation of Akt was also inhibited by gefitinib, but only partly, suggesting a mechanism in addition to EGFR transactivation. Inhibition of PKC blocked neurotensin-induced DNA synthesis in HCT116 cells.</p> <p>Conclusions</p> <p>While acting predominantly through PKC in Panc-1 cells and via EGFR transactivation in HT29 cells, neurotensin used both these pathways in HCT116 cells. In these cells, neurotensin-induced activation of ERK and stimulation of DNA synthesis was PKC-dependent, whereas activation of the PI3K/Akt pathway was mediated by stimulation of metalloproteinases and subsequent transactivation of the EGFR. Thus, the data show that the signalling mechanisms mediating the effects of neurotensin involve multiple pathways and are cell-dependent.</p

Towards a framework for the design of quantitative experiments: Human-computer interaction and accessibility research

Many students and researchers struggle with the design and analysis of empirical experiments. Such issue may be caused by lack of knowledge about inferential statistics and suitable software tools. Often, students and researchers conduct experiments without having a complete plan for the entire lifecycle of the process. Difficulties associated with the statistical analysis are often ignored. Consequently, one may end up with data that cannot be easily analyzed. This paper discusses the concept sketch of a framework that intends to help students and researchers to design correct empirical experiments by making sound design decisions early in the research process. The framework consists of an IDE, i.e., Integrated (statistical experiment) Development Environment. This IDE helps the user structures an experiment by giving continuous feedback drawing the experimenter’s attention towards potential problems. The output of the IDE is an experimental structure and data format that can be imported to common statistical packages such as JASP in addition to providing guidance about what tests to use

Hostage of the Software: Experiences in Teaching Inferential Statistics to Undergraduate Human-Computer Interaction Students and a Survey of the Literature

Students’ knowledge of inferential statistics is lacking in many computer science study programs. Yet, the needs for inferential statistical skills have emerged with new fields of study such as human-computer interaction involving observation of human activity. This paper presents experiences teaching inferential statistics to undergraduate computer science students with a focus on the actual goals of the investigations and not the mechanisms and mathematics of statistics. The teaching framework involves teaching statistics as a set of systematic black-box tools

Statistics-IDE: Supporting the design of empirical experiments for non-experts during early stages of research projects

Empirical experimentation and inferential statistics are often perceived as challenging among students and researchers. Yet, empirical experiments are highly relevant and appropriate methods in several areas of ergonomics and human computer interaction. This paper argues that the traditional research proposal written in prose is an ineffective mechanism for ensuring sound experiments. This paper discusses the idea of tool-based support for the design of quantitative experiments. The objective of an experimental design tool is to help the experimenter make correct and wise decisions early in the process by providing feedback on ideas at early stages. We discuss the benefits of the IDE (Integrated Development Environment) paradigm as a platform for designing quantitative experiments

The impact of gender, level of amputation and diabetes on prosthetic fit rates following major lower extremity amputation

Background: Diabetes Mellitus (DM) is a leading cause of major lower extremity amputation (LEA). Objective: To examine the influence of gender, level of amputation and DM status on being fit with a prosthetic limb following LEA. Study Design: Retrospective analysis of the SPARG dataset. Results: Within the cohort (n=1735) 64% were men (n=1112) and 48% (n=834) had DM. Those with DM were younger than those without: mean 67.5 years and 71.1 years respectively (p&lt;0.001). Trans-Tibial Amputation (TTA): Trans-Femoral Amputation (TFA) ratio was 2.33 in those with DM, and 0.93 in those without. 41% of those with DM were successfully fit with a prosthetic limb compared to 38% of those without DM. Male gender positively predicted fitting with a prosthetic limb at both TTA (p=0.001) and TFA (p=0.001) levels. Bilateral amputations and increasing age were negative predictors of fitting with a prosthetic limb (p&lt;0.001). DM negatively predicted fitting with a prosthetic limb at TFA level (p&lt;0.001). Mortality was 17% for the cohort, 22% when the amputation was at TFA level. Conclusion: Those with DM were younger, with more TTA, both are good predictors of fitting with a prosthetic limb, despite this, successful limb fit rates were no better than those without DM