530 research outputs found

    A view of evolution by a Christian biologist

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    This paper, which originated as an address to a gathering of Dutch Reformed Ministers in Potchefstroom, deals with the response of a Christian to concepts of evolution. The paper looks at the concept of “the beginning”, the origin of life , genetics, mutation and natural selection, the origin of diversity or speciation, man as a biological species, the missing link (in which attention is given to various theories), and finally theories of human evolution. These include the neoteny theory, the savannah theory and the aquatic theory. Following a discussion of the various aspects of these theories, the authors go on to a discussion of the evolution of intelligence and culture, and reach the conclusion that “for a Christian, evolution may help him to understand more about God and his love and his work, and also then to have more security in the belief in God”

    Quantifying the influence of urban development on runoff in South Africa

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    Characterization of putative Wnt3a-Inducible Enhancers

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    The Wnt signaling pathway has been previously shown to play a major role in regulating bone metabolism and it is emerging as a target for the therapeutic intervention of bone thinning disorders such as osteoporosis. Several Wnt proteins have been shown to be expressed in bone and mutations in Wnt pathway members such as Wnt co-receptor Lrp5 and Wnt inhibitor Sost have been shown to be associated with low or high bone mass disorders, however, very little is known about specific roles played by different Wnt ligands in bone development, repair and remodeling. To identify downstream targets of Wnt signaling we sequence RNA synthesized by Wnt3a treated osteoblasts and found 214 genes to be significantly up-regulated by \u3e2-fold in the presence of Wnt3a ligand. Computational analysis of ChipSeq data in the loci of these 214 genes predicted 163 putative Wnt-inducible enhancers. In this project, we sought to functionally validate these putative enhancer elements that may account for the Wnt3a-dependent activation of these 214 transcripts. Candidate enhancers were cloned, transfected into osteoblast-like cell lines, and examined for transgene expression in the presence and absence of recombinant Wnt3a protein. Preliminary data suggests that several noncoding elements may have enhancer properties both in the absence or presence of Wnt3a, in vitro

    Nanocomposite Scaffold for Chondrocyte Growth and Cartilage Tissue Engineering: Effects of Carbon Nanotube Surface Functionalization

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    The goal of this study was to assess the long-term biocompatibility of single-wall carbon nanotubes (SWNTs) for tissue engineering of articular cartilage. We hypothesized that SWNT nanocomposite scaffolds in cartilage tissue engineering can provide an improved molecular-sized substrate for stimulation of chondrocyte growth, as well as structural reinforcement of the scaffold\u27s mechanical properties. The effect of SWNT surface functionalization (-COOH or -PEG) on chondrocyte viability and biochemical matrix deposition was examined in two-dimensional cultures, in three-dimensional (3D) pellet cultures, and in a 3D nanocomposite scaffold consisting of hydrogels + SWNTs. Outcome measures included cell viability, histological and SEM evaluation, GAG biochemical content, compressive and tensile biomechanical properties, and gene expression quantification, including extracellular matrix (ECM) markers aggrecan (Agc), collagen-1 (Col1a1), collagen-2 (Col2a1), collagen-10 (Col10a1), surface adhesion proteins fibronectin (Fn), CD44 antigen (CD44), and tumor marker (Tp53). Our findings indicate that chondrocytes tolerate functionalized SWNTs well, with minimal toxicity of cells in 3D culture systems (pellet and nanocomposite constructs). Both SWNT-PEG and SWNT-COOH groups increased the GAG content in nanocomposites relative to control. The compressive biomechanical properties of cell-laden SWNT-COOH nanocomposites were significantly elevated relative to control. Increases in the tensile modulus and ultimate stress were observed, indicative of a tensile reinforcement of the nanocomposite scaffolds. Surface coating of SWNTs with -COOH also resulted in increased Col2a1 and Fn gene expression throughout the culture in nanocomposite constructs, indicative of increased chondrocyte metabolic activity. In contrast, surface coating of SWNTs with a neutral -PEG moiety had no significant effect on Col2a1 or Fn gene expression, suggesting that the charged nature of the -COOH surface functionalization may promote ECM expression in this culture system. The results of this study indicate that SWNTs exhibit a unique potential for cartilage tissue engineering, where functionalization with bioactive molecules may provide an improved substrate for stimulation of cellular growth and repair

    Genetic evidence that SOST inhibits WNT signaling in the limb

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    AbstractSOST is a negative regulator of bone formation, and mutations in human SOST are responsible for sclerosteosis. In addition to high bone mass, sclerosteosis patients occasionally display hand defects, suggesting that SOST may function embryonically. Here we report that overexpression of SOST leads to loss of posterior structures of the zeugopod and autopod by perturbing anterior–posterior and proximal–distal signaling centers in the developing limb. Mutant mice that overexpress SOST in combination with Grem1 and Lrp6 mutations display more severe limb defects than single mutants alone, while Sost−/− significantly rescues the Lrp6−/− skeletal phenotype, signifying that SOST gain-of-function impairs limb patterning by inhibiting the WNT signaling through LRP5/6

    The role of Data Transfer Agreements in ethically managing data sharing for research in South Africa

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    A multitude of legislation impacts the use of samples and data for research in South Africa (SA). With the coming into effect of the Protection of Personal Information Act No. 4 of 2013 (POPIA) in July 2021, recent attention has been given to safeguarding research participants' personal information. The protection of participants' privacy in research is essential, but it is not the only risk at stake in the use and sharing of personal information. Other rights and interests that must also be considered and safeguarded include the right to non-discrimination, the right to dignity, and the right to enjoy the benefits of scientific progress. This can be achieved by ensuring that the ethical values and universal principles that underpin the research landscape, namely equity, reciprocity, justice and solidarity, are embedded in the regulatory framework for the management and use of personal information. This paper advocates an integrated bioethics approach to the use of personal information for research in SA. A key feature in embedding such an approach is a Data Transfer Agreement (DTA) that appropriately integrates the safeguards and protections set out by our regulatory framework with bioethical rules and procedures when personal information is used and shared for research purposes. This paper thus calls for the development of a national DTA that is guided by key ethical principles when data are shared for research purposes. This paper will be followed by a webinar on 23 June 2022 hosted by the Department of Science and Innovation and the SA Medical Research Council, where the recommendations and suggestions set out herein will be unpacked, discussed and debated by relevant stakeholders

    Use of sepsis-related diagnostic criteria in primary care:a survey among general practitioners

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    BACKGROUND: Use of sepsis-criteria in hospital settings is effective in realizing early recognition, adequate treatment and reduction of sepsis-associated morbidity and mortality. Whether general practitioners (GPs) use these diagnostic criteria is unknown. OBJECTIVE: To gauge the knowledge and use of various diagnostic criteria. To determine which parameters GPs associate with an increased likelihood of sepsis. METHODS: Two thousand five hundred and sixty GPs were invited and 229 agreed to participate in a survey, reached out to through e-mail and WhatsApp groups. The survey consisted of two parts: the first part aimed to obtain information about the GP, training and knowledge about sepsis recognition, and the second part tested specific knowledge using six realistic cases. RESULTS: Two hundred and six questionnaires, representing a response rate of 8.1%, were eligible for analysis. Gut feeling (98.1%) was the most used diagnostic method, while systemic inflammatory response syndrome (37.9%), quick Sequential Organ Failure Assessment (qSOFA) (7.8%) and UK Sepsis Trust criteria (UKSTc) (1.5%) were used by the minority of the GPs. Few of the responding GPs had heard of either the qSOFA (27.7%) or the UKSTc (11.7%). Recognition of sepsis varied greatly between GPs. GPs most strongly associated the individual signs of the qSOFA (mental status, systolic blood pressure, capillary refill time and respiratory rate) with diagnosing sepsis in the test cases. CONCLUSIONS: GPs mostly use gut feeling to diagnose sepsis and are frequently not familiar with the 'sepsis-criteria' used in hospital settings, although clinical reasoning was mostly in line with the qSOFA score. In order to improve sepsis recognition in primary care, GPs should be educated in the use of available screening tools

    The impacts of social restrictions during the COVID-19 pandemic on the physical activity levels of over 50-year olds: the CHARIOT COVID-19 Rapid Response (CCRR) cohort study

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    Objectives To quantify the associations between shielding status and loneliness at the start of the COVID-19 pandemic, and physical activity (PA) levels throughout the pandemic. Methods Demographic, health and lifestyle characteristics of 7748 cognitively healthy adults aged >50, and living in London, were surveyed from April 2020 to March 2021. The International Physical Activity Questionnaire (IPAQ) short-form assessed PA before COVID-19 restrictions, and up to 6 times over 11 months. Linear mixed models investigated associations between baseline shielding status, loneliness, and time-varying PA. Results Participants who felt ‘often lonely’ at the outset of the pandemic completed an average of 522 and 547 fewer Metabolic Equivalent of Task (MET) minutes/week (95% CI: -809, -236, pConclusions Those shielding or lonely at pandemic onset were likely to have completed low levels of PA during the pandemic. These associations are influenced by co-morbidities and health status
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