Short communication: The effect of ultrasound at 256 KHz on Microcystis aeruginosa, with and without gas vacuoles

The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily. Furthermore, changes in culture characteristics, e.g., flotation and gas vesicle formation, were determined. The results showed that, in contrast to the control, both ultrasonic-treated cultures had a lower chlorophyll-a concentration and cell aggregates were disrupted. Transmission electron microscopy confirmed a collapse of gas vacuoles in the environmental culture, while the laboratory culture, which did not contain gas vacuoles, showed many membrane-damaged cells. It was concluded that ultrasonic treatment of M. aeruginosa caused the disruption of gas vacuoles and destruction of cell membranes.Keywords: Ultrasound, cyanobacteria, Microcystis aeruginosa, chlorophyll, gas vacuole

The foreign language classroom anxiety scale and academic achievement: an overview of the prevailing literature and a meta-analysis

Foreign language learners experience a unique type of anxiety during the language learning process: Foreign Language Classroom Anxiety (FLCA). This situation-specific anxiety is frequently examined alongside academic achievement in foreign language courses. The present meta-analysis examined the relationship between FLCA measured through the Foreign Language Classroom Anxiety Scale (FLCAS) and five forms of academic achievement: general academic achievement and four competency-specific outcome scores (reading-, writing-, listening-, and speaking academic achievement). A total of k = 99 effect sizes were analysed with an overall sample size of N = 14128 in a random effects model with Pearson correlation coefficients. A moderate negative correlation was found between FLCA and all categories of academic achievement (e.g., general academic achievement: r = -.39; k = 59; N = 12585). The results of this meta analysis confirm the negative association between FLCA and academic achievement in foreign language courses

Discharge of water containing waste emanating from land to the marine environment: A water quality management perspective

The National Water Act, 1998 (Act 36 of 1998) mandates the Department of Water Affairs and Forestry to manage all water containing waste (wastewater), which emanates from land-based sources and which directly impact on the marine environment. These sources include sea outfalls, storm water drains, canals, rivers and diffuse sources of pollution. To date there are many places where wastewater is being discharged into the sea. More than forty sea outfalls are formalised through authorisations issued in terms of the old Water Act, 1956 (Act 54 of 1956) and the National Water Act, 1998 (Act 36 of 1998). In order to protect water quality, effluent standards were applied under the old Water Act to discharges into the water resource. However, the National Water Act, 1998 follows a receiving water quality objectives approach recognising differences in the assimilative capacity of different resources. Both approaches have the same main objective namely to maintain the resource at a quality fit for use by other users. The same principle applies to discharges to the marine environment. In addition, South Africa, as a signatory to a number of international Conventions and treaties such as the London Convention, is committed to certain requirements pertaining to the disposal of waste at sea. To meet such requirements, a very clear policy on what could be allowed for discharge to sea is required for South Africa. Such a policy should be very clear on what is allowed, why it is allowed and the conditions that apply for such discharges in order for this country to retain international credibility. In this paper the authors provide a concise discussion on: • The development of an operational policy providing the strategic view on marine disposal, as well as the goal, basic principles, ground rules and management framework that will be applied to the discharge of land-derived wastewater to the marine environment; and • Overview of procedures to guide authorities and managers in terms of the administrative and institutional responsibilities in dealing with land-derived wastewater discharges to the marine environment of South Africa.br> Water SA Vol. 30 (5) 2005: pp.56-6

The value of medical student hepatitis B immunisation as part of clinical skills training in the Clinical Skills Unit of the University of the Free State

Background: It is compulsory for medical students of the University of the Free State to be immunised against hepatitis B before they have contact with clinical patients. Previously, the students were vaccinated on campus at the student health services. With the implementation of Curriculum 2000 (the revised MBChB programme), hepatitis B immunisation, as an example of an invasive procedure, was incorporated into the medical students’ clinical skills training programme. The aim of this study was to assess the students’ perceptions regarding immunising their peers, being immunised by their peers and the educational value of this process.Methods: Medical students in Phase II of the MBChB programme were included in this observational descriptive study and participation was voluntary. Students immunised their peers with a hepatitis B vaccine in the upper arm under the supervision of medical and nursing personnel in the laboratory of the Skills Unit. After the final immunisation, the students completed an anonymous questionnaire.Results: Sixty-six students completed the questionnaire. Of these, 80% felt that that they had improved their understanding of the theory of immunisation. Some (8%) students preferred to have the immunisation performed at a clinic or by a doctor and 6% had a problem with being vaccinated by a peer. A few (3%) students found it unacceptable to be immunised in a mixed gender group, 5% thought they had suffered complications and 5% indicated that there had been inadequate supervision. Most of the students (98%) responded positively to immunising their peers and 95% felt that it was advantageous to receive the immunisation in the skills laboratory environment. Approximately half (56%) of the students wanted to receive additional important immunisations.Conclusion: Students were positive about practising immunisation techniques on their peers.SA Fam Pract 2005;47(4): 54-5

Breeding for biofuel production

Tese de doutoramento em Ciências Farmacêuticas, na especialidade de Biologia Celular e Molecular, apresentada à Faculdade de Farmácia da Universidade de CoimbraAs sinapses excitatórias são estruturas dinâmicas e a forma como neurónios vizinhos comunicam entre si é ajustada consoante a actividade neuronal. A esta propriedade chama-se plasticidade sináptica e a nível molecular está correlacionada com a aprendizagem e a memória. A potenciação sináptica de longa duração (LTP) é a forma de plasticidade sináptica mais estudada sendo definida como um fortalecimento duradouro na comunicação entre neurónios vizinhos desencadeado pela actividade neuronal. Pelo contrário, a depressão sináptica de longa duração (LTD) é caracterizada por uma diminuição duradoura da potência sináptica. Alterações moleculares nos mecanismos de plasticidade sináptica estão na base de muitas doenças neurológicas e psiquiátricas. Algumas das modificações sinápticas ao nível estrutural, bioquímico e funcional associadas com a plasticidade sináptica requerem a traducão de mRNAs (RNA mensageiros) localizados nas dendrites, resultando em alterações no proteoma sináptico. Várias evidências mostram que a síntese proteica em dendrites desempenha um papel fundamental em várias formas de plasticidade sináptica, incluindo a LTP mediada pelo BDNF (factor neurotrófico derivado do cérebro). Contudo, pouco se sabe sobre a identidade dos mRNA que são traduzidos ao nível da sinapse em resposta ao BDNF e sobre os mecanismos de regulação envolvidos. Além disso, também está ainda por esclarecer de que modo muitas das alterações no proteoma sináptico contribuem para os fenómenos de plasticidade sináptica. Neste trabalho investigámos o papel da Pyk2 (cinase de resíduos de tirosina rica em prolina do tipo 2) na mediação dos efeitos do BDNF na sinapse. A Pyk2 é uma cinase de resíduos de tirosina pertencente à família das FAK (cinases de adesão focal), que desempenha uma grande variedade de funções no sistema nervoso central, incluindo o control da LTP e da LTD por mecanismos que envolvem a regulação dos receptores NMDA (N-metil-D-aspartato). Além disso, pensa-se que esta cinase desempenha um papel importante na remodelação da arquitectura das espículas sinápticas e da arborização dendritica, induzidas pela actividade neuronal. Observámos que a Pyk2 é traduzida ao nível da sinapse e acumulada nas densidades pós-sinápticas de neurónios do hipocampo após a estimulação com BDNF. A acumulação dendritica da Pyk2 em resposta à estimulação com BDNF requer a participação da RBP (proteína que liga RNA), hnRNPK (ribonucleoproteína nuclear heterogénea do tipo K). Estas observações estão de acordo com os resultados anteriores do nosso laboratório mostrando que: (i) a hnRNPK é acumulada nas dendrites dos neurónios do hipocampo após o estimulação com BDNF; (ii) a ligação do mRNA da Pyk2 à hnRNPK é regulada por BDNF. Usando um protocolo químico para aumentar a actividade neuronal e induzir LTP também observámos que a Pyk2 se acumula na sinapse por um mecanismo dependente de BDNF. A principal função da Pyk2 ao nível da densidade pós-sináptica tem sido associada à regulação das correntes mediadas pelos recetores NMDA através da interação direta com a Src, outra cinase de resíduos de tirosina. Neste estudo, observámos que o tratamento com BDNF aumenta a expressão superficial dos receptores NMDA que contêm a subunidade GluN2B, ao nível da sinapse, por um mecanismo dependente da síntese proteica. De acordo com estas observações, observou-se que a estimulação com BDNF aumenta os níveis de Pyk2 fosforilada/activada de forma específica ao nível da sinapse, o que sugere uma regulação diferencial da atividade da cinase. O aumento dos níveis sinápticos dos recetores NMDA induzido pelo BDNF também depende da Pyk2 e da sua actividade de cinase. Por outro lado, também se observou que em condições de repouso a manutenção na membrana celular dos recetores NMDA contendo subunidades GluN2B depende da atividade de cinase da Pyk2. Finalmente, a sobreexpressão da Pyk2 em neurónios do hipocampo foi suficente para mimetizar os efeitos do BDNF na expressão superficial dos receptores NMDA que contêm a subunidade GluN2B. No seu conjunto, os resultados mostram que o BDNF induz a activação/acumulação da Pyk2 por um mecanismo que envolve a hnRNPK e a síntese dendritica da Pyk2, resultando num aumento da expressão superfical dos receptores NMDA que contêm a subunidade GluN2B. Este mecanismo pode mediar os efeitos do BDNF nos défices cognitivos que são característicos de certas doenças do cérebro.Excitatory synapses are dynamic entities and adjust their strength depending on the activity. This property is named synaptic plasticity and is considered the cellular correlate of learning and memory. Long-term potentiation (LTP) is the best studied form of synaptic plasticity and by definition it is considered as an activity-induced sustained increase in synaptic strength. Long-term depression (LTD) is the opposite form of plasticity, and is characterized by an activity-induced sustained decrease in synaptic strength. Alterations in the molecular basis of synaptic plasticity events underlie several neurological and psychiatric disorders. Some of the structural, biochemical and functional modifications of the synapse associated with synaptic plasticity require translation of dendritic-localized mRNAs, with concomitant alterations in the synaptic proteome. Multiple lines of evidence show that dendritic protein synthesis plays a key role in several forms of synaptic plasticity, including in brain-derived neurotrophic factor (BDNF)-mediated LTP. However, the identity of the mRNAs that are synaptically translated in response to BDNF and the regulatory mechanisms involved are poorly understood. Furthermore, how these changes in the proteome contribute to the plastic alterations of the synapse also remains to be uncovered. In this work, we investigated a role for Pyk2 (proline-rich tyrosine kinase 2) as a mediator of the effects of BDNF at the synapse. Pyk2 is a non-receptor tyrosine kinase, belonging to the FAK (focal adhesion kinase) family of proteins, which plays a wide range of functions in the central nervous system (CNS), including the control of LTP and LTD by mechanisms involving the regulation of NMDA (N-methyl-D-aspartate) receptors. Furthermore, this kinase is thought to play an important role in the activity-induced remodeling of spine architecture and dendritic arborization. We found that the protein kinase Pyk2 is synaptically translated in hippocampal neurons and accumulates at post-synaptic density following BDNF treatment. The dendritic accumulation of Pyk2 upon stimulation with BDNF requires the participation of the RNA-binding protein hnRNPK (heterogeneous nuclear ribonucleoprotein K). This is in accordance with previous results from our laboratory showing that (i) hnRNPK is accumulated in dendrites of hippocampal neurons upon BDNF treatment and (ii) the binding of Pyk2 mRNA to hnRNPK is regulated by BDNF. Using a chemical protocol to increase neuronal activity and to induce LTP, we also observed that Pyk2 accumulates at the synapse by a mechanism requiring BDNF. The main function of Pyk2 at the post-synaptic compartment has been attributed to the regulation of NMDA receptor currents through a direct interaction with a different tyrosine kinase, Src. Herein we found that BDNF treatment increases the surface expression of GluN2B-containing NMDA receptors (NMDAR) at synapses, by a mechanism dependent on protein synthesis. In agreement with these observations, the levels of phosphorylated/activated Pyk2 were specifically enhanced at the synapse upon BDNF treatment, suggesting a compartment-specific regulation of Pyk2 activity by BDNF. The BDNF-induced increase on surface NMDARs also requires Pyk2 and its kinase activity. The maintenance of basal levels of GluN2B-containing NMDAR at the cell surface was also dependent on Pyk2 kinase activity. Finally, overexpression of Pyk2 in hippocampal neurons was sufficient, per se, to mimic the BDNF-induced increase in GluN2B-NMDAR surface expression. Taken together, the results show that BDNF induces synaptic activation/accumulation of Pyk2 by a mechanism involving hnRNPK and dendritic Pyk2 synthesis, resulting in an enhancement in the surface levels of GluN2B-containing NMDAR. This mechanism may mediate the effects of BDNF on synaptic plasticity and may constitute a novel therapeutic target to restore the cognitive deficits characteristic of some brain disorders.FCT - SFRH/BD/80332/201

Re-imagining community participation at the district level: Lessons from the DIALHS collaboration.

In South Africa, the value of community participation as one of the central components of a primary health care approach is highlighted in legislation, policy documents and strategic plans. There is widespread acceptance that community participation strengthens community empowerment, disease prevention and access to services. Since 2010, the District Innovation and Action Learning for Health System Development collaboration has co-produced knowledge about how to strengthen district health systems. Nested within this collaboration is a series of engagements seeking to understand and strengthen community participation including a multi-stakeholder health risks and assets mapping activity; ‘Local Action Group’ initiatives; reflective meetings with service colleagues about community participation experiences; and a capacity-development initiative (community participation-related short courses and mentoring). These engagements hold a number of lessons for those interested in enhancing the population orientation of primary health care and the district health system, the first of which is the clear benefit to those interested in community roles and engagement of convening spaces for dialogue. However, it is not easy to generate and sustain these spaces. Through the application of a framework of collective capacity, this chapter aims to shed light on why this is the case, and in so doing, to highlight a second lesson, which is the perhaps unrecognised capacities of certain cadres, particularly environmental health practitioners, in the implementation of community participation. Ultimately, the chapter seeks to stimulate thinking and engagement about the ways in which dialogue and participation can enrich the South African health system

Community-based curriculum in psychiatric nursing science

As community-based health care delivery is now a prominent feature of the health care system in South Africa, nursing curricula are being challenged to prepare student nurses for community based nursing roles and responsibilities. The purpose of this study was to describe guidelines for a community-based curriculum in psychiatric nursing science for a nursing college in KwaZulu-Natal. A qualitative, quantitative, exploratory, descriptive and contextual design was employed. To reach the purpose of the study, a situational analysis was done in three phases to identify the principles for a community-based curriculum for psychiatric nursing science. Phase I: A document analysis of relevant government policies and legislation. Phase II: Statistics from psychiatric hospitals and community psychiatric clinics. Phase III: Focus group interviews with nurse educators and literature control and conceptual framework The principles obtained from the three phases were used to formulate the guidelines for a community-based curriculum in psychiatric nursing science (Phase IV). Eight guidelines with practical implications are described for the implementation of a Community-based curriculum in Psychiatric Nursing Science

The effect of different anaesthetic mask shapes on the anatomical dead space using infant, child and adult part-task trainers

Dead space is the portion of tidal volume that does not participate in alveolar gas exchange. The purpose of this study was to compare the dead space contribution of differently shaped masks, of the same size, by measuring the volume of each mask. The study was conducted in the Clinical Simulation Unit of the School of Medicine, University of the Free State (UFS) using formed masks with inflatable polyvinylchloride (PVC) cuffs and rounded masks with non-inflatable PVC cuffs. The masks were placed on the faces of the infant, child and adult part-task trainers as well as on a flat surface. The cuffs of the formed masks were inflated to 5 cm water and 70 cm water. Masks were filled with water and the volume was measured.The volumes (ml) of the masks on the flat surface were significantly larger than those measured on the part-task trainers’ faces. The volume of the rounded masks was greater than the volume of the formed masks. The amount of cuff inflation pressure (5 cm water vs. 70 cm water) did not lead to a significant change in mask volume: 102.3 ml (standard deviation [SD] 75.9) vs. 110.2 ml (SD 82.3), averaged for all sizes.Formed masks contribute less to anatomical dead space than rounded masks and are thus possibly the better choice. Cuff inflation pressure has insignificant influence on dead space volume.Keywords: anaesthesia, anatomical dead space, inhalation, masks, pulmonary ventilation, respirator

By the old gods and the new: the effect of Foreign Language Classroom Anxiety and Enjoyment Congruence on Self-Perceived Proficiency

The negative emotion of Foreign Language Classroom Anxiety (FLCA) and the positive emotion of Foreign Language Enjoyment (FLE) have both been linked to foreign language (FL) learners’ Self-Perceived Proficiency (SPP). In linear correlational studies, SPP has been found to be negatively affected by FLCA and positively affected by FLE. However, linear correlational research methods are limited in the extent to which they can depict these interrelations. In this study, we examined how different levels of FLCA and FLE influenced SPP in concert in a sample of n = 1039 FL learners by utilising polynomial regression with response surface analysis. The response model generated visually depicted a complex SPP pattern as a result of differing levels of FLCA and FLE. This three-dimensional model provides considerable insight into the interaction of positive and negative emotions above and beyond what could be derived from ‘classical’ methods of correlation and linear regression