The sublethal salinity tolerance of selected freshwater macroinvertebrate species

Increasing salinity levels pose a threat to freshwater ecosystems in many regions of the world. This study investigated the sublethal effects of salinity on four macroinvertebrate species commonly occurring in Australian freshwater ecosystems. These were; the worm Lumbriculus variegatus (Annelida: Oligochaeta), the snail Physa acuta (Gastropoda: Physidae), the shrimp Paratya australiensis ( Decapoda: Atyidae) and the midge Chironomus tepperi (Diptera: Chironomidae). The effects of salinity on growth, development and reproduction of these species were investigated through a series of laboratory tests. The tolerances of early life stages of these species were also investigated. The effects of salinity on C. tepperi were assessed across a full life-cycle of exposure. The observed sublethal salinity tolerances of the investigated species were compared to their acute salinity tolerances. These relationships were investigated to assess if there is a correlation between the sublethal and acute salinity tolerance of freshwater macroinvertebrate species. With the exception of L. variegatus each of the investigated species displayed life stages with lower salinity tolerances than older aquatic life stages of the species. This was not investigated for L. variegatus . Sublethal effects of salinity were observed for all of the investigated species at salinities significantly lower than those affecting their short term survival. In many cases these effects had obvious implications for the survival ability of the species. Examples include zero reproduction and/or growth at salinities displaying minimal impacts on short term survival. The pattern of effect with increasing salinity varied between different end points. Many of the investigated effects displayed non-threshold responses with increased salinity. This necessitated consideration of the magnitude of effect. Many end points, particularly growth, displayed optimal levels at slightly elevated salinities. Common trends in the relative salinity tolerance of different life stages and sublethal end points were identified. Sublethal responses were generally more salt sensitive than the survival of eggs and juveniles. Growth and reproduction of freshwater macroinvertebrates were found to be highly sensitive to increased salinity. The cumulative effects of salinity on survival, growth, development and reproduction across a full life-cycle of exposure was found to greatly reduce recruitment potential. A 50% reduction in potential recruitment of second generation C. tepperi was observed at a salinity more than 80% lower than the 96-hr LC 50 (the concentration lethal to 50% of test organisms) for the species. The sublethal salinity tolerance of the investigated species was closely related to their acute salinity tolerance. The ratio between the EC50 (the concentration producing a response in 50% of test organisms) for the most sensitive sublethal end point, recruitment of C. tepperi , and the 96-hour LC 50 for the species was 0.17. Mean ratios between EC50 values for growth and reproduction end points and LC50 values observed for this and other studies were around 0.45. While further research is required, the proportional relationship between the sublethal and acute tolerance of macroinvertebrate species observed in this study allows the sublethal effects of salinity to be taken into account in aquatic ecosystem management where only acute tolerance data are available

Student Outcomes from the Collective Design and Delivery of Culturally Relevant Engineering Outreach Curricula in Rural and Appalachian Middle Schools

Middle school is a pivotal time for career choice, and research is rich with studies on how students perceive engineering, as well as corresponding intervention strategies to introduce younger students to engineering and inform their conceptions of engineering. Unfortunately, such interventions are typically not designed in culturally relevant ways. Consequently, there continues to be a lack of students entering engineering and a low level of diverse candidates for this profession. The purpose of this study was to explore how students in rural and Appalachian Virginia conceive of engineering before and after engagement with culturally relevant hands-on activities in the classroom. We used student responses to the Draw an Engineer Test (DAET), consisting of a drawing and several open-ended prompts administered before and after the set of engagements, to answer our research questions related to changes in students’ conceptions of engineering. We used this study to develop recommendations for teachers for the use of such engineering engagement practices and how to best assess their outcomes, including looking at the practicality of the DAET. Overall, we found evidence that our classroom engagements positively influenced students’ conceptions of engineering in these settings

Teaching Chinese to international students in China: political rhetoric and ground realities

This paper presents an on-going study of the enactment of The International Promotion of Chinese Policy (国际汉语推广政策). It explores how Chinese teaching and learning take place in a Chinese university under the Study in China Programme which allows international students, after a period of intensive Chinese language learning, to transfer to academic courses taught in Chinese for Chinese students at the tertiary level. This programme has expanded in recent years in response to the government's goal to enhance China's soft power globally. By studying policy documents, engaging in conversations with students and teachers, and observing classrooms, our study reveals that there are conflicting interests of social actors at national, institutional and individual levels, causing considerable conflicts and tensions in three aspects:1) the divergent goals of internationalisation between the government and the higher education institution; 2) the imperative need of academic Chinese for subject learning and the actual offer of Chinese for everyday communication; and 3) the competing role of English versus Chinese as a lingua franca for communication in the university setting. These conflicts make it difficult for international students to benefit from the subject courses, and for universities to implement successful language programmes for international students, and this renders the political objective of this programme difficult to achieve

The effects of social density, spatial density, noise, and office views on perceived personal space in the virtual workplace

Here we sought to understand how perceived personal space is influenced by a number of variables that could influence Indoor Environmental Quality (IEQ); specifically, we tested how different levels of social density, spatial density, noise presence, and type of view impact the appreciation of personal space in a shared office environment. We employed virtual reality (VR) to simulate shared and single occupancy offices and devised a novel measure of personal space estimation. We also used a traditional personal space satisfaction score. Participants experienced greater perceived personal space when (1) in a sparsely populated rather than a dense office, (2) in a private office rather than an open plan office, and (3) having any view outside of the office. We did not find an effect of the presence of noise or increased social density (with spatial density held constant) on the perception of personal space

Identification and validation of multiple cell surface markers of clinical-grade adipose-derived mesenchymal stromal cells as novel release criteria for good manufacturing practice-compliant production

Background: Clinical translation of mesenchymal stromal cells (MSCs) necessitates basic characterization of the cell product since variability in biological source and processing of MSCs may impact therapeutic outcomes. Although expression of classical cell surface markers (e.g., CD90, CD73, CD105, and CD44) is used to define MSCs, identification of functionally relevant cell surface markers would provide more robust release criteria and options for quality control. In addition, cell surface expression may distinguish between MSCs from different sources, including bone marrow-derived MSCs and clinical-grade adipose-derived MSCs (AMSCs) grown in human platelet lysate (hPL). Methods: In this work we utilized quantitative PCR, flow cytometry, and RNA-sequencing to characterize AMSCs grown in hPL and validated non-classical markers in 15 clinical-grade donors. Results: We characterized the surface marker transcriptome of AMSCs, validated the expression of classical markers, and identified nine non-classical markers (i.e., CD36, CD163, CD271, CD200, CD273, CD274, CD146, CD248, and CD140B) that may potentially discriminate AMSCs from other cell types. More importantly, these markers exhibit variability in cell surface expression among different cell isolates from a diverse cohort of donors, including freshly prepared, previously frozen, or proliferative state AMSCs and may be informative when manufacturing cells. Conclusions: Our study establishes that clinical-grade AMSCs expanded in hPL represent a homogeneous cell culture population according to classical markers,. Additionally, we validated new biomarkers for further AMSC characterization that may provide novel information guiding the development of new release criteria

Loss of histone methyltransferase Ezh2 stimulates an osteogenic transcriptional program in chondrocytes but does not affectcartilage development

Ezh2 is a histone methyltransferase that suppresses osteoblast maturation and skeletal development. We evaluated the roleof Ezh2 in chondrocyte lineage differentiation and endochondral ossification. Ezh2 was genetically inactivated in the mesenchymal, osteoblastic, and chondrocytic lineages in mice using the Prrx1-Cre,Osx1-Cre, and Col2a1-Cre drivers, respectively. Wild-type and conditional knockout mice were phenotypically assessed by grossmorphology, histology, and micro-CT imaging. Ezh2-deficient chondrocytes in micromass culture models were evaluated usingRNA-sequencing, histologic evaluation, and western blotting. Aged mice with Ezh2 deficiency were also evaluated for prematuredevelopment of osteoarthritis using radiographic analysis. Ezh2 deficiency in murine chondrocytes reduced bone density at 4 weeks of age, although caused no other gross developmentaleffects. Knockdown of Ezh2 in chondrocyte micromass cultures resulted in a global reduction in trimethylation of histone 3lysine 27 (H3K27me3) and altered differentiation in vitro. RNA-seq analysis revealed enrichment of an osteogenic gene expressionprofile in Ezh2 deficient chondrocytes. Joint development proceeded normally in the absence of Ezh2 in chondrocytes withoutinducing excessive hypertrophy or premature osteoarthritis in vivo. In summary, loss of Ezh2 reduced H3K27me3 levels, increased expression of osteogenic genes in chondrocytes, and resulted ina transient post-natal bone phenotype. Remarkably, Ezh2 activity is dispensable for normal chondrocyte maturation and endochondralossification in vivo, even though it appears to have a critical role during early stages of mesenchymal lineage-commitment

Protocol for north of England and Scotland study of tonsillectomy and adeno-tonsillectomy in children (NESSTAC). A pragmatic randomised controlled trial comparing surgical intervention with conventional medical treatment in children with recurrent sore throats

BACKGROUND: Uncertainties surrounding the effectiveness and cost-effectiveness of childhood tonsillectomy for recurrent sore throat led the NHS Health Technology Assessment Programme to commission this research to evaluate the effectiveness and cost-effectiveness of tonsillectomy and adeno-tonsillectomy in comparison with standard non-surgical management in children aged under 16 with recurrent throat infections. The aim is to evaluate if tonsillectomy and adeno-tonsillectomy reduces the number of episodes of sore throats among children to a clinically significant extent. METHODS/DESIGN: A simple prospective pragmatic randomised controlled trial with economic analysis and prospective cohort study of non-trial participants comparing surgical intervention with conventional medical treatment. The treatment arm will receive tonsillectomy and adeno-tonsillectomy while in the control arm non-surgical conventional medical treatment only will be used. The primary outcome measure will be reported number of episodes of sore throat over two years with secondary outcomes measures of reported number of episodes of sore throat, otitis media and upper respiratory tract infection which invoke a GP consultation; reported number of symptom-free days; reported severity of sore throats and surgical and anaesthetic morbidity. The study will take place in five hospitals in the UK. The trial population will be 406 children aged 4–15 on their last birthday with recurrent sore throat referred by primary care to the 5 otolaryngology departments. The duration of the study is seven years (July 2001- July 2008). DISCUSSION: As with all pragmatic randomised controlled trials it is impossible to control the external environment in which the research is taking place. Since this trial began a number of factors have arisen which could affect the outcome including; a reduction in the incidence of respiratory tract infections, marked socio-economic differences in consultation rates, the results from the National Prospective Tonsillectomy Audit and the Government's waiting list initiatives

Upregulation of PPARβ/δ Is Associated with Structural and Functional Changes in the Type I Diabetes Rat Diaphragm

Diabetes mellitus is associated with alterations in peripheral striated muscles and cardiomyopathy. We examined diaphragmatic function and fiber composition and identified the role of peroxisome proliferator-activated receptors (PPAR alpha and beta/delta) as a factor involved in diaphragm muscle plasticity in response to type I diabetes.Streptozotocin-treated rats were studied after 8 weeks and compared with their controls. Diaphragmatic strips were stimulated in vitro and mechanical and energetic variables were measured, cross bridge kinetics assessed, and the effects of fatigue and hypoxia evaluated. Morphometry, myosin heavy chain isoforms, PPAR alpha and beta/delta gene and protein expression were also assessed. Diabetes induced a decrease in maximum velocity of shortening (-14%, P<0.05) associated with a decrease in myosin ATPase activity (-49%, P<0.05), and an increase in force (+20%, P<0.05) associated with an increase in the number of cross bridges (+14%, P<0.05). These modifications were in agreement with a shift towards slow myosin heavy chain fibers and were associated with an upregulation of PPARbeta/delta (+314% increase in gene and +190% increase in protein expression, P<0.05). In addition, greater resistances to fatigue and hypoxia were observed in diabetic rats.Type I diabetes induced complex mechanical and energetic changes in the rat diaphragm and was associated with an up-regulation of PPARbeta/delta that could improve resistance to fatigue and hypoxia and favour the shift towards slow myosin heavy chain isoforms