202 research outputs found
Including the Excluded: The Case of Slow Learners at Buloba Primary School, Uganda
This article describes a study of Mathematics teachers at Buloba Primary School in Uganda. The purpose was to analyse the teachers’ perceptions, essential practices for creating inclusive classroom environments for slow learners, and implementation challenges. This quasi-experimental research included a focus group discussion, an interview with the headteacher, three lesson observations and post-observation focus group discussions. The results indicate that the teachers have mixed perceptions and several practices: peer learning, certain teaching methods, linking teaching to real-world applications, seating environment, and providing a threat -free classroom environment. Highlighted challenges include heavy workloads, limited time, inadequate training, mixed classes of both slow and fast learners, inability to identify slow learners, class size and lack of knowledge. It emphasizes the need to define and develop reference frameworks of teacher competencies and institutionalize in-service teacher education programmes through school-based practices and research.Group C: Teacher Professional Developmen
Kinetic Analysis and Prediction of Thermal Decomposition Behavior of Tertiary Pyridine Resin in the Nitrate Form
AbstractThe thermal decomposition behavior of the tertiary pyridine resin, which was used during the nuclide-separation process in the Advanced Optimization by Recycling Instructive Elements (Advanced ORIENT) cycle, was investigated in its nitrate form (TPR-NO3), in order to determine ways of preventing its runaway reaction. A thermal analysis of TPR-NO3 and an analysis of the gases produced during decomposition were employed for the purpose. In addition, the kinetics parameters were evaluated via a kinetic analysis of the empirical thermal data. Finally, the validity of the reaction model was assessed by comparing the thermal behavior predicted by the estimated reaction model with that determined by the results of a gram-scale heating test performed in our previous study. We found that, when TPR-NO3 was heated, first, nitric acid was removed. Subsequently, TPR-NO3 was oxidized by the removed nitric acid. Under the assumption that it took place an autocatalytic oxidation and nth order thermal decomposition in parallel, the thermogravimetric analysis data could be fitted very well using a nonlinear regression model. The thermal behavior of TPR-NO3 could be predicted by the reaction model determined in this study under conditions where the cooling effect owing to evaporation was ignored. In addition, the maximum temperature and time to maximum rate of a runaway reaction predicted using the determined reaction model gave the result on the side of prudence
Perivascular Nitric Oxide Activates Notch Signaling and Promotes Stem-like Character in PDGF-Induced Glioma Cells
SummaryeNOS expression is elevated in human glioblastomas and correlated with increased tumor growth and aggressive character. We investigated the potential role of nitric oxide (NO) activity in the perivascular niche (PVN) using a genetic engineered mouse model of PDGF-induced gliomas. eNOS expression is highly elevated in tumor vascular endothelium adjacent to perivascular glioma cells expressing Nestin, Notch, and the NO receptor, sGC. In addition, the NO/cGMP/PKG pathway drives Notch signaling in PDGF-induced gliomas in vitro, and induces the side population phenotype in primary glioma cell cultures. NO also increases neurosphere forming capacity of PDGF-driven glioma primary cultures, and enhances their tumorigenic capacity in vivo. Loss of NO activity in these tumors suppresses Notch signaling in vivo and prolongs survival of mice. This mechanism is conserved in human PDGFR amplified gliomas. The NO/cGMP/PKG pathway's promotion of stem cell-like character in the tumor PVN may identify therapeutic targets for this subset of gliomas
Atg9a deficiency causes axon-specific lesions including neuronal circuit dysgenesis
Conditional knockout mice for Atg9a, specifically in brain tissue, were generated to understand the roles of ATG9A in the neural tissue cells. The mice were born normally, but half of them died within one wk, and none lived beyond 4 wk of age. SQSTM1/p62 and NBR1, receptor proteins for selective autophagy, together with ubiquitin, accumulated in Atg9a-deficient neurosoma at postnatal d 15 (P15), indicating an inhibition of autophagy, whereas these proteins were significantly decreased at P28, as evidenced by immunohistochemistry, electron microscopy and western blot. Conversely, degenerative changes such as spongiosis of nerve fiber tracts proceeded in axons and their terminals that were occupied with aberrant membrane structures and amorphous materials at P28, although no clear-cut degenerative change was detected in neuronal cell bodies. Different from autophagy, diffusion tensor magnetic resonance imaging and histological observations revealed Atg9a-deficiency-induced dysgenesis of the corpus callosum and anterior commissure. As for the neurite extensions of primary cultured neurons, the neurite outgrowth after 3 d culturing was significantly impaired in primary neurons from atg9a-KO mouse brains, but not in those from atg7-KO and atg16l1-KO brains. Moreover, this tendency was also confirmed in Atg9a-knockdown neurons under an atg7-KO background, indicating the role of ATG9A in the regulation of neurite outgrowth that is independent of autophagy. These results suggest that Atg9a deficiency causes progressive degeneration in the axons and their terminals, but not in neuronal cell bodies, where the degradations of SQSTM1/p62 and NBR1 were insufficiently suppressed. Moreover, the deletion of Atg9a impaired nerve fiber tract formation
The Institutional Presidency from a Comparative Perspective: Argentina and Brazil since the 1980s
This paper focuses on the evolution of the institutional presidency - meaning the cluster of agencies that directly support the chief of the executive - in Argentina and Brazil since their redemocratization in the 1980s. It investigates what explains the changes that have come about regarding the size of the institutional presidency and the types of agency that form it. Following the specialized literature, we argue that the growth of the institutional presidency is connected to developments occurring in the larger political system - that is, to the political challenges that the various presidents of the two countries have faced. Presidents adjust the format and mandate of the different agencies under their authority so as to better manage their relations with the political environment. In particular, we argue that the type of government (coalition or single-party) has had consequences for the structure of the presidency or, in other words, that different cabinet structures pose different challenges to presidents. This factor has not played a significant role in presidency-related studies until now, which have hitherto mostly been based on the case of the United States. Our empirical references, the presidencies of Argentina and Brazil, typical cases of coalitional as well as single-party presidentialism respectively allow us to show the impact of the type of government on the number and type of presidential agencies
Suppression of autophagy impedes glioblastoma development and induces senescence
The function of macroautophagy/autophagy during tumor initiation or in established tumors can be highly distinct and context-dependent. To investigate the role of autophagy in gliomagenesis, we utilized a KRAS-driven glioblastoma mouse model in which autophagy is specifically disrupted via RNAi against Atg7, Atg13 or Ulk1. Inhibition of autophagy strongly reduced glioblastoma development, demonstrating its critical role in promoting tumor formation. Further supporting this finding is the observation that tumors originating from Atg7-shRNA injections escaped the knockdown effect and thereby still underwent functional autophagy. In vitro, autophagy inhibition suppressed the capacity of KRAS-expressing glial cells to form oncogenic colonies or to survive low serum conditions. Molecular analyses revealed that autophagy-inhibited glial cells were unable to maintain active growth signaling under growth-restrictive conditions and were prone to undergo senescence. Overall, these results demonstrate that autophagy is crucial for glioma initiation and growth, and is a promising therapeutic target for glioblastoma treatment
A De Novo Mouse Model of C11orf95-RELA Fusion-Driven Ependymoma Identifies Driver Functions in Addition to NF-κB.
The majority of supratentorial ependymomas (ST-ependymomas) have few mutations but frequently display chromothripsis of chromosome 11q that generates a fusion between C11orf95 and RELA (RELAFUS). Neural stem cells transduced with RELAFUSex vivo form ependymomas when implanted in the brain. These tumors display enhanced NF-κB signaling, suggesting that this aberrant signal is the principal mechanism of oncogenesis. However, it is not known whether RELAFUS is sufficient to drive de novo ependymoma tumorigenesis in the brain and, if so, whether these tumors also arise from neural stem cells. We show that RELAFUS drives ST-ependymoma formation from periventricular neural stem cells in mice and that RELAFUS-induced tumorigenesis is likely dependent on a series of cell signaling pathways in addition to NF-κB
miR-34a Repression in Proneural Malignant Gliomas Upregulates Expression of Its Target PDGFRA and Promotes Tumorigenesis
Glioblastoma (GBM) and other malignant gliomas are aggressive primary neoplasms of the brain that exhibit notable refractivity to standard treatment regimens. Recent large-scale molecular profiling has revealed distinct disease subclasses within malignant gliomas whose defining genomic features highlight dysregulated molecular networks as potential targets for therapeutic development. The “proneural” designation represents the largest and most heterogeneous of these subclasses, and includes both a large fraction of GBMs along with most of their lower-grade astrocytic and oligodendroglial counterparts. The pathogenesis of proneural gliomas has been repeatedly associated with dysregulated PDGF signaling. Nevertheless, genomic amplification or activating mutations involving the PDGF receptor (PDGFRA) characterize only a subset of proneural GBMs, while the mechanisms driving dysregulated PDGF signaling and downstream oncogenic networks in remaining tumors are unclear. MicroRNAs (miRNAs) are a class of small, noncoding RNAs that regulate gene expression by binding loosely complimentary sequences in target mRNAs. The role of miRNA biology in numerous cancer variants is well established. In an analysis of miRNA involvement in the phenotypic expression and regulation of oncogenic PDGF signaling, we found that miR-34a is downregulated by PDGF pathway activation in vitro. Similarly, analysis of data from the Cancer Genome Atlas (TCGA) revealed that miR-34a expression is significantly lower in proneural gliomas compared to other tumor subtypes. Using primary GBM cells maintained under neurosphere conditions, we then demonstrated that miR-34a specifically affects growth of proneural glioma cells in vitro and in vivo. Further bioinformatic analysis identified PDGFRA as a direct target of miR-34a and this interaction was experimentally validated. Finally, we found that PDGF-driven miR-34a repression is unlikely to operate solely through a p53-dependent mechanism. Taken together, our data support the existence of reciprocal negative feedback regulation involving miR-34 and PDGFRA expression in proneural gliomas and, as such, identify a subtype specific therapeutic potential for miR-34a
A unique missense variant in the E1A-binding protein P400 gene is implicated in schizophrenia by whole-exome sequencing and mutant mouse models
Genetic and epidemiological evidence has suggested that genetic factors are important in schizophrenia, although its pathophysiology is poorly understood. This study used whole-exome sequencing to investigate potential novel schizophrenia-causing genes in a Japanese family containing several members affected by severe or treatment-resistant schizophrenia. A missense variant, chr12:132064747C>T (rs200626129, P2805L), in the E1A-binding protein P400 (EP400) gene completely segregated with schizophrenia in this family. Furthermore, numerous other EP400 mutations were identified in the targeted sequencing of a schizophrenia patient cohort. We also created two lines of Ep400 gene-edited mice, which had anxiety-like behaviours and reduced axon diameters. Our findings suggest that rs200626129 in EP400 is likely to cause schizophrenia in this Japanese family, and may lead to a better understanding and treatment of schizophrenia
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