290 research outputs found

    Effectiveness of Wholistic Education among SDA Secondary Schools in Arusha and Kilimanjaro Regions, Tanzania

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    This study was conducted among SDA secondary schools in Arusha and Kilimanjaro regions to establish the effectiveness of wholistic Education.  Out of five schools, three were randomly selected for participation. The three schools had a total of 120 Form Four students from whom 92 were selected to fill the questionnaire through simple random sampling. The analysis involved descriptive statistics, t-test and Pearson Correlation. The study concluded that wholistic education is effective in the schools under investigation. This is due to the fact that students, regardless of their religious affiliation, agreed with most of items that measured the variables in the questionnaire. Furthermore, there is significant positive relationship between the physical, the spiritual and mental aspects of the wholistic education. Therefore, there is need for leadership in schools under investigation to improve the quality of food provided to students since they were not satisfied with the quality of food provided. Since the physical, mental and spiritual aspects correlate with one another, there is need to ensure a balanced curricular and extra-curricular programs that accommodate the three aspects so that learners may receive quality and balanced education which prepares them physically, mentally and spiritually for better service in this world and in the world to come

    Effects of Extracurricular Activities on Students’ Motivation to Learn among Seventh - day Adventist Affiliated Secondary Schools in Morogoro, Tanzania

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    This study was pursued to establish the effects of extracurricular activities on students’ motivation to learn among Seventh- day Adventist affiliated Secondary Schools in Morogoro, Tanzania. The study employed the quantitative research approach using the descriptive-correlational design. The targeted population of the study was 398 students from two SDA-affiliated Secondary Schools in Morogogoro. A sample of 199 students was determined through the Taro Yamane’s mathematical formula. Data was collected through a self-constructed questionnaire based on literature review. The first two research questions were analyzed through descriptive statistics while the third was analyzed through Pearson Product Moment Correlation Coefficient. Based on the findings, the study concluded that students actively participated in extracurricular activities and were motivated to learn through various ways. The more students participate in extracurricular activities, the more their learning motivation increased. Therefore, participation in extracurricular activities enhanced the learning motivation for students. The study recommends that students be encouraged to actively participate in various extracurricular activities for betterment of their physical, mental and spiritual wellbeing and for the improved learning motivation. Secondly, schools should improve the quality of extracurricular activities so that students may gain richer experiences as they keep participating in the extra-curricular activities

    Inter-species differences in regulation of the progranulin–sortilin axis in TDP-43 cell models of neurodegeneration

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    Cytoplasmic aggregates and nuclear depletion of the ubiquitous RNA-binding protein TDP-43 have been described in the autoptic brain tissues of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTLD) patients and both TDP-43 loss-of-function and gain-of-function mechanisms seem to contribute to the neurodegenerative process. Among the wide array of RNA targets, TDP-43 regulates progranulin (GRN) mRNA stability and sortilin (SORT1) splicing. Progranulin is a secreted neurotrophic and neuro-immunomodulatory factor whose endocytosis and delivery to the lysosomes are regulated by the neuronal receptor sortilin. Moreover, GRN loss-of-function mutations are causative of a subset of FTLD cases showing TDP-43 pathological aggregates. Here we show that TDP-43 loss-of-function differently affects the progranulin\u2013sortilin axis in murine and human neuronal cell models. We demonstrated that although TDP-43 binding to GRN mRNA occurs similarly in human and murine cells, upon TDP-43 depletion, a different control of sortilin splicing and protein content may determine changes in extracellular progranulin uptake that account for increased or unchanged secreted protein in murine and human cells, respectively. As targeting the progranulin\u2013sortilin axis has been proposed as a therapeutic approach for GRN-FTLD patients, the inter-species differences in TDP-43-mediated regulation of this pathway must be considered when translating studies from animal models to patients

    Information in a network of neuronal cells: Effect of cell density and short-term depression

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    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect

    Relating the rate of growth of metal nanoparticles to cluster size distribution in electroless deposition

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    Electroless deposition on patterned silicon substrates enables the formation of metal nanomaterials with tight control over their size and shape. In the technique, metal ions are transported by diffusion from a solution to the active sites of an autocatalytic substrate where they are reduced as metals upon contact. Here, using diffusion limited aggregation models and numerical simulations, we derived relationships that correlate the cluster size distribution to the total mass of deposited particles. We found that the ratio ξ between the rates of growth of two different metals depends on the ratio γ between the rates of growth of clusters formed by those metals through the linearity law ξ = 14(γ - 1). We then validated the model using experiments. Different from other methods, the model derives k using as input the geometry of metal nanoparticle clusters, decoded by SEM or AFM images of samples, and a known reference

    Vascular endothelial growth factor-A and Poly(A) binding protein-interacting protein 2 expression in human head and neck carcinomas: correlation and prognostic significance

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    Vascular endothelial growth factor-A (VEGF-A) has been demonstrated to play an important role in tumour angiogenesis and to influence prognosis in many cancers. However its prognostic value in head and neck squamous cell carcinomas (HNSCCs) remains controversial. Therefore, we investigated the clinical relevance of VEGF-A expression in HNSCCs and analysed whether its expression was associated with PAIP2 protein levels, a VEGF-A mRNA-binding partner that strongly regulates VEGF-A expression in tissue culture. We determined the correlation of VEGF-A and PAIP2 protein levels, quantitatively evaluated in tumour tissue homogenates from 54 patients with HNSCC, to clinicopathological parameters. We showed that VEGF-A expression in HNSCC is correlated to the stage of tumour differentiation (P=0.050) and is an independent prognostic factor for progression-free survival (P=0.001) and overall survival (P=0.0004). In a pharynx carcinoma cell line, we demonstrated by RNA interference that VEGF-A expression is closely controlled by PAIP2. Moreover, in human HNSCCs, VEGF-A expression is significantly correlated to PAIP2 protein levels (P=0.0018). Nevertheless, PAIP2 expression is associated with neither clinicopathological factors nor patient's survival. Our data suggest that, in contrast to PAIP2 protein levels, which are unrelated to tumour prognosis, VEGF-A expression could serve as a prognostic marker in head and neck cancer and may be helpful for targeted therapies

    Human Cancer Cell Radiation Response Investigated through Topological Analysis of 2D Cell Networks

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    Clonogenic assays are routinely used to evaluate the response of cancer cells to external radiation fields, assess their radioresistance and radiosensitivity, estimate the performance of radiotherapy. However, classic clonogenic tests focus on the number of colonies forming on a substrate upon exposure to ionizing radiation, and disregard other important characteristics of cells such their ability to generate structures with a certain shape. The radioresistance and radiosensitivity of cancer cells may depend less on the number of cells in a colony and more on the way cells interact to form complex networks. In this study, we have examined whether the topology of 2D cancer-cell graphs is influenced by ionizing radiation. We subjected different cancer cell lines, i.e. H4 epithelial neuroglioma cells, H460 lung cancer cells, PC3 bone metastasis of grade IV of prostate cancer and T24 urinary bladder cancer cells, cultured on planar surfaces, to increasing photon radiation levels up to 6 Gy. Fluorescence images of samples were then processed to determine the topological parameters of the cell-graphs developing over time. We found that the larger the dose, the less uniform the distribution of cells on the substrate—evidenced by high values of small-world coefficient (cc), high values of clustering coefficient (cc), and small values of characteristic path length (cpl). For all considered cell lines, >1 for doses higher or equal to 4 Gy, while the sensitivity to the dose varied for different cell lines: T24 cells seem more distinctly affected by the radiation, followed by the H4, H460 and PC3 cells. Results of the work reinforce the view that the characteristics of cancer cells and their response to radiotherapy can be determined by examining their collective behavior—encoded in a few topological parameters—as an alternative to classical clonogenic assays

    Nano-topography Enhances Communication in Neural Cells Networks

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    Abstract Neural cells are the smallest building blocks of the central and peripheral nervous systems. Information in neural networks and cell-substrate interactions have been heretofore studied separately. Understanding whether surface nano-topography can direct nerve cells assembly into computational efficient networks may provide new tools and criteria for tissue engineering and regenerative medicine. In this work, we used information theory approaches and functional multi calcium imaging (fMCI) techniques to examine how information flows in neural networks cultured on surfaces with controlled topography. We found that substrate roughness S a affects networks topology. In the low nano-meter range, S a  = 0–30 nm, information increases with S a . Moreover, we found that energy density of a network of cells correlates to the topology of that network. This reinforces the view that information, energy and surface nano-topography are tightly inter-connected and should not be neglected when studying cell-cell interaction in neural tissue repair and regeneration

    Synthesis of plasmonic gold nanoparticles on soft materials for biomedical applications

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    Plasmonic metal nanomaterials are usually supported by rigid substrates, typically made of silicon or glass. Recently, there has been growing interest in developing soft plasmonic devices. Such devices are low weight, low cost, exhibit elevated flexibility and improved mechanical properties. Moreover, they maintain the features of conventional nano-optic structures, such as the ability to enhance the local electromagnetic field. On account of these characteristics, they show promise as efficient biosensors in biological, medical, and bio-engineering applications. Here, we demonstrate the fabrication of soft polydimethylsiloxane (PDMS) plasmonic devices. Using a combination of techniques, including electroless deposition, we patterned thin membranes of PDMS with arrays of gold nanoparticle clusters. Resulting devices show regular patterns of gold nanoparticles extending over several hundreds of microns and are moderately hydrophilic, with a contact angle of about 80°. At the nanoscale, scanning electron and atomic force microscopy of samples reveal an average particle size of ∼50 nm. The nanoscopic size of the particles, along with their random distribution in a cluster, promotes the enhancement of electromagnetic fields, evidenced by numerical simulations and experiments. Mechanical characterization and the stress-strain relationship indicate that the device has a stiffness of 2.8 MPa. In biological immunoassay tests, the device correctly identified and detected anti-human immunoglobulins G (IgG) in solution with a concentration of 25 μg/ml
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