Teaching Evolution Concepts to Early Elementary School Students

State and national standards call for teaching evolution concepts as early as kindergarten, which provides motivation to continue developing science instruction and curriculum for young learners. The importance of addressing students’ folk theories regarding science justifies teaching evolution early in K-12 education. In this project, we developed, implemented, and researched standards-based lessons to teach elements of evolution (speciation and adaption) to kindergarteners and second graders. Our lessons attended to the students’ prior knowledge, and utilized inquiry and modeling to teach and assess their ability to recognize patterns of similarity and differences among organisms. Using their products and comments as evidence, it was apparent the students were able to communicate recognition of patterns and effectively apply their knowledge in near transfer activities, indicating they achieved our learning objectives. This provides support for teaching evolution concepts in the early grades and evidence of the ability for young children to effectively engage in supported inquiry and modeling for learning science.     

Perineural local anaesthetic catheter after major lower limb amputation trial (PLACEMENT): study protocol for a randomised controlled pilot study

Background

Pain after major lower limb amputation for peripheral arterial disease (PAD) is a significant problem. A perineural catheter (PNC) can be placed adjacent to the major nerve at the time of amputation with a continuous local anaesthetic infusion given postoperatively to try and reduce pain. Although low-quality observational data suggest that PNC usage reduces postoperative opioid requirements, there are limited data regarding its effect on pain. The aim of PLACEMENT is to explore the feasibility of running an effectiveness trial to assess the impact of a PNC with continuous local anaesthetic infusion, inserted at the time of amputation, on short and medium-term postoperative outcomes.

Methods/design

Fifty patients undergoing a major lower limb amputation (below or above the knee) for PAD will be recruited from two centres. Patients will be randomised in a 1:1 ratio to receive standard postoperative analgesia, with or without insertion of a PNC and local anaesthetic infusion for the first 5 postoperative days. Outcome data will be captured for the first 5 days, including pain scores (primary outcome, captured three times a day), opioid use, nausea or vomiting, itching, dizziness and complications. Patients will be contacted 2 and 6 months after surgery to assess quality of life, phantom limb pain, chronic stump pain and total healthcare costs. Semi-structured interviews will be conducted with at least 10 patients (dependent on saturation of analytic themes on preliminary coding) purposefully sampled to achieve variation in site and study arm. Interviews will explore patients’ perception of post-amputation pain and its treatment, and experience of study processes. Semi-structured interviews with 5–10 health professionals will explore feasibility, fidelity, and acceptability of the study. Data from this pilot will be used to assess feasibility of, and estimate parameters to calculate the sample size for an effectiveness trial. Full ethical approval has been granted (Wales Research Ethics Committee 3 reference number 16/WA/0353).

Discussion

PLACEMENT will be the first study to explore the feasibility of running an effectiveness trial on PNC usage for postoperative pain in amputees, and provide parameters to calculate the appropriate sample size for this study.

Trial registration

ISRCTN.com, ISRCTN85710690. Registered on 21 October 2016.European Clinical Trials Database (EudraCT), 2016-003544-37. Registered on 24 August 2016.

     

Effects of trehalose polycation end-group functionalization on plasmid DNA uptake and transfection

In this study, we have synthesized six analogs of a trehalose-pentaethylenehexamine glycopolymer (Tr4) that contain (1A) adamantane, (1B) carboxy, (1C) alkynyl-oligoethyleneamine, (1D) azido trehalose, (1E) octyl, or (1F) oligoethyleneamine end groups and evaluated the effects of polymer end group chemistry on the ability of these systems to bind, compact, and deliver pDNA to cultured HeLa cells. The polymers were synthesized in one-pot azide-alkyne cycloaddition reactions with an adaptation of the Carothers equation for step-growth polymerization to produce a series of polymers with similar degrees of polymerization. An excess of end-capping monomer was added at the end of the polymerizations to maximize functionalization efficiency, which was evaluated with GPC, NMR, and MALDI-TOF. The polymers were all found to bind and compact pDNA at similarly low N/P ratios and form polyplexes with plasmid DNA. The effects of the different end group structures were most evident in the polyplex internalization and transfection assays in the presence of serum as determined by flow cytometry and luciferase gene expression, respectively. The Tr4 polymers end-capped with carboxyl groups (1B) (N/P = 7), octyne (1E) (N/P = 7), and oligoethyleneamine (1F) (N/P = 7), were taken into cells as polyplex and exhibited the highest levels of fluorescence, resulting from labeled plasmid. Similarly, the polymers end-functionalized with carboxyl groups (1E at N/P = 7), octyl groups (1E at N/P = 15), and in particular oligoethyleneamine groups (1F at N/P = 15) yielded dramatically higher reporter gene expression in the presence of serum. This study yields insight into how very subtle structural changes in polymer chemistry, such as end groups can yield very significant differences in the biological delivery efficiency and transgene expression of polymers used for pDNA delivery.     

Composition of the adult digestive tract bacterial microbiome based on seven mouth surfaces, tonsils, throat and stool samples

Background

To understand the relationship between our bacterial microbiome and health, it is essential to define the microbiome in the absence of disease. The digestive tract includes diverse habitats and hosts the human body's greatest bacterial density. We describe the bacterial community composition of ten digestive tract sites from more than 200 normal adults enrolled in the Human Microbiome Project, and metagenomically determined metabolic potentials of four representative sites.

Results

The microbiota of these diverse habitats formed four groups based on similar community compositions: buccal mucosa, keratinized gingiva, hard palate; saliva, tongue, tonsils, throat; sub- and supra-gingival plaques; and stool. Phyla initially identified from environmental samples were detected throughout this population, primarily TM7, SR1, and Synergistetes. Genera with pathogenic members were well-represented among this disease-free cohort. Tooth-associated communities were distinct, but not entirely dissimilar, from other oral surfaces. The Porphyromonadaceae, Veillonellaceae and Lachnospiraceae families were common to all sites, but the distributions of their genera varied significantly. Most metabolic processes were distributed widely throughout the digestive tract microbiota, with variations in metagenomic abundance between body habitats. These included shifts in sugar transporter types between the supragingival plaque, other oral surfaces, and stool; hydrogen and hydrogen sulfide production were also differentially distributed.

Conclusions

The microbiomes of ten digestive tract sites separated into four types based on composition. A core set of metabolic pathways was present across these diverse digestive tract habitats. These data provide a critical baseline for future studies investigating local and systemic diseases affecting human health.     

Net pelagic heterotrophy in mesotrophic and oligotrophic basins of a large, temperate lake

Understanding the effects of trophic status and dissolved organic carbon concentration (DOC) on lake carbon cycling is essential for accurate ecosystem carbon models. Using isotopically labelled substrates we assessed spatial and temporal variability in bacterial respiration (BR) and algal primary production (PP) in two trophically, morphometrically and hydrologically different basins in Loch Lomond, a large temperate lake in Scotland. GIS modelling was used to construct a whole lake balance for bacterial production/respiration and PP, and from this the proportion of heterotrophy fuelled by allochthonous carbon was estimated. We tested the hypotheses that trophic status and DOC concentration affect the balance between PP and BR and examined which is the more significant driving factor. Additionally we estimated the percentage of BR that is fuelled by terrestrial carbon. PP varied seasonally and showed inter-basin homogeneity. BR was greatest in the mesotrophic south basin in autumn, which corresponded to measured peak DOC input, though over an annual cycle no relationship was observed between BR and DOC concentration. The PP:BR ratio was 0.37 ± 0.30 and 0.3 ± 0.45 in the north and south basins, respectively, assuming a bacterial growth efficiency of 0.1. We have found that allochthonous carbon potentially supports a substantial quantity of pelagic production, even during periods of high photosynthesis. Less productive systems are thought to be dominated by heterotrophic processes. However, we have found that the mesotrophic basin of a large lake to be as heterotrophic as its neighbouring oligotrophic basin, an observation that has implications for our understanding of modelling of the role of lakes in linking the terrestrial-atmospheric carbon cycle.     

Control of invertase synthesis in sugar cane. Loci of auxin and glucose effects

In tissue slices from rapidly expanding internodes of sugar cane the vacuolar invertase level is a function of the balance between synthesis and destruction. The enzyme is destroyed in the tissue at an approximately constant rate with a half time of 2 hours. Invertase synthesis is regulated by both auxin and glucose. From studies with inhibitors of protein and RNA synthesis we conclude that auxin alters the rate of synthesis and glucose increases the rate of destruction of messenger RNA required for the production of invertase.