250 research outputs found

    Penggunaan Media Gambar untuk Meningkatkan Aktivitas Belajar Ilmu Pengetahuan Alam Kelas IV Sekolah Dasar

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    Of Yustina Ladu 2012 using picture media of increasing of students study resuit in science 4 elementary 48 Ketanjak This observation held to know result of study of studenst by science program by picture media. Observations method that used is descriptive by form of research in class oktion.Rresearch subjects are eleven students in SDN 48 Ketanjak Meliau district Sanggau regency. Students indudes five men and six women. Synergy Indiator in this research is seventy percent student increase study activity and result of study with get sexty become eighty grades instrument of score colletion is researchs paper and test of study result

    Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 GHz and 7 GHz

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    Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages of stellar evolution, the properties of the ambient interstellar medium, and the physics of particle acceleration and shocks. For a fraction of SNRs, multi-wavelength coverage from radio to ultra high-energies has been provided, constraining their contributions to the production of Galactic cosmic rays. Although radio emission is the most common identifier of SNRs and a prime probe for refining models, high-resolution images at frequencies above 5 GHz are surprisingly lacking, even for bright and well-known SNRs such as IC443 and W44. In the frameworks of the Astronomical Validation and Early Science Program with the 64-m single-dish Sardinia Radio Telescope, we provided, for the first time, single-dish deep imaging at 7 GHz of the IC443 and W44 complexes coupled with spatially-resolved spectra in the 1.5-7 GHz frequency range. Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling and resulting in accurate continuum flux density measurements. The integrated flux densities associated with IC443 are S_1.5GHz = 134 +/- 4 Jy and S_7GHz = 67 +/- 3 Jy. For W44, we measured total flux densities of S_1.5GHz = 214 +/- 6 Jy and S_7GHz = 94 +/- 4 Jy. Spectral index maps provide evidence of a wide physical parameter scatter among different SNR regions: a flat spectrum is observed from the brightest SNR regions at the shock, while steeper spectral indices (up to 0.7) are observed in fainter cooling regions, disentangling in this way different populations and spectra of radio/gamma-ray-emitting electrons in these SNRs.Comment: 13 pages, 9 figures, accepted for publication to MNRAS on 18 May 201

    Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129

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    We present new observations of the galaxy cluster 3C 129 obtained with the Sardinia Radio Telescope in the frequency range 6000-7200 MHz, with the aim to image the large-angular-scale emission at high-frequency of the radio sources located in this cluster of galaxies. The data were acquired using the recently-commissioned ROACH2-based backend to produce full-Stokes image cubes of an area of 1 deg x 1 deg centered on the radio source 3C 129. We modeled and deconvolved the telescope beam pattern from the data. We also measured the instrumental polarization beam patterns to correct the polarization images for off-axis instrumental polarization. Total intensity images at an angular resolution of 2.9 arcmin were obtained for the tailed radio galaxy 3C 129 and for 13 more sources in the field, including 3C 129.1 at the galaxy cluster center. These data were used, in combination with literature data at lower frequencies, to derive the variation of the synchrotron spectrum of 3C 129 along the tail of the radio source. If the magnetic field is at the equipartition value, we showed that the lifetimes of radiating electrons result in a radiative age for 3C 129 of t_syn = 267 +/- 26 Myrs. Assuming a linear projected length of 488 kpc for the tail, we deduced that 3C 129 is moving supersonically with a Mach number of M=v_gal/c_s=1.47. Linearly polarized emission was clearly detected for both 3C 129 and 3C 129.1. The linear polarization measured for 3C 129 reaches levels as high as 70% in the faintest region of the source where the magnetic field is aligned with the direction of the tail.Comment: 19 pages, 17 figures, accepted for publication in MNRA

    Seroprevalence of parvovirus B19 and its clinical effect among anaemic SCA patients in Northeastern Nigeria

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    ABSTRACT Sickle cell anaemia (SCA) is a globally widespread genetic disorder affecting 5% of the world's over 6 billion people. Parvovirus infection and the resulting aplastic crisis is a recognised complication in individuals with SCA. Aplastic crisis increases the need for blood transfusion and its attendant risk of Transfusion Transmissible Infection (TTI). Hence there is a vicious cycle in which Parvovirus B19 causes aplastic crisis which in turn causes increased transfusion need; and transfusion increases risk of transfusion transmissible infection in which parvovirus B19 is included in certain parts of the world. Sickle cell anaemia is associated with foetal death and infection with parvovirus B19 increases the risk to early mortality. The objective of this study was to determine the seroprevalence of parvovirus B19 among SCA and compare with that of controls in the study area. Furthermore clinical and laboratory profile of subjects were analysed to identify possible correlation with parvovirus B19 seropositivity and explore the possibility of involvement of white cell and platelets. A total of 90 subjects comprising 45 consecutive SCA case subjects and 45 age-and sex-matched non SCA controls were studied in a cross sectional comparative study. Ten millilitres of blood was drawn from the antecubital fossa of each subject after obtaining informed consent. The 10mls of blood was divided into two aliquots, 4.5 mls was added into EDTA anticoagulated bottle and was used for basic complete blood count (CBC), while the remaining 5mls was added into a plain specimen container allowed to clot and serum obtained to test for anti-parvovirus B19 IgG and IgM using an immunochromatography based technique specifically BIOCARD TM Parvo B19 diagnostic test kit. There was male preponderance in the study. The SCA subjects comprised 26 males and 19 females (male to female ratio = 1.4:1), while the non-SCA controls comprised 25 males and 20 females (male to female ratio 1.3:1).. The analysis of anti-parvovirus B19 IgG antibody revealed a prevalence of 23.3% among SCA cases with 18.9% among controls. The haematological profile is not affected by IgG seropositivity. However pregnancy outcome revealed that the total number of stillbirths is 12 among IgG seropositive SCA cases which is higher than the 6 encountered in IgG seronegative SCA subjects; the difference is statistically significant (p=0.04)

    Innovation and the circular economy: A systematic literature review

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    The circular economy emerged as an alternative model to the linear system, which now appears to be reaching its physical limitations. To transition to a circular economy, companies must not only be aware of but also engage in more sustainable practices. For such a transition, companies must rethink and innovate their business models and the ways they propose value to their clients while simultaneously considering environmental and social facets. This systematic literature review sought to map out from the company perspective the key topics interrelated with innovation and the circular economy, describing the internal and external factors to consider in such transition processes. Key lines of research were identified, and suggestions for future research and for facilitating movement toward a circular economy are provided. This work contributes to deepening the literature by identifying the priority areas concerning the circular economy and encouraging future research that meets international standards of excellence.info:eu-repo/semantics/publishedVersio

    E2F1 Regulates Cellular Growth by mTORC1 Signaling

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    During cell proliferation, growth must occur to maintain homeostatic cell size. Here we show that E2F1 is capable of inducing growth by regulating mTORC1 activity. The activation of cell growth and mTORC1 by E2F1 is dependent on both E2F1's ability to bind DNA and to regulate gene transcription, demonstrating that a gene induction expression program is required in this process. Unlike E2F1, E2F3 is unable to activate mTORC1, suggesting that growth activity could be restricted to individual E2F members. The effect of E2F1 on the activation of mTORC1 does not depend on Akt. Furthermore, over-expression of TSC2 does not interfere with the effect of E2F1, indicating that the E2F1-induced signal pathway can compensate for the inhibitory effect of TSC2 on Rheb. Immunolocalization studies demonstrate that E2F1 induces the translocation of mTORC1 to the late endosome vesicles, in a mechanism dependent of leucine. E2F1 and leucine, or insulin, together affect the activation of S6K stronger than alone suggesting that they are complementary in activating the signal pathway. From these studies, E2F1 emerges as a key protein that integrates cell division and growth, both of which are essential for cell proliferation

    Development of Mouse Hepatocyte Lines Permissive for Hepatitis C Virus (HCV)

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    The lack of a suitable small animal model for the analysis of hepatitis C virus (HCV) infection has hampered elucidation of the HCV life cycle and the development of both protective and therapeutic strategies against HCV infection. Human and mouse harbor a comparable system for antiviral type I interferon (IFN) induction and amplification, which regulates viral infection and replication. Using hepatocytes from knockout (ko) mice, we determined the critical step of the IFN-inducing/amplification pathways regulating HCV replication in mouse. The results infer that interferon-beta promoter stimulator (IPS-1) or interferon A receptor (IFNAR) were a crucial barrier to HCV replication in mouse hepatocytes. Although both IFNARko and IPS-1ko hepatocytes showed a reduced induction of type I interferons in response to viral infection, only IPS-1-/- cells circumvented cell death from HCV cytopathic effect and significantly improved J6JFH1 replication, suggesting IPS-1 to be a key player regulating HCV replication in mouse hepatocytes. We then established mouse hepatocyte lines lacking IPS-1 or IFNAR through immortalization with SV40T antigen. Expression of human (h)CD81 on these hepatocyte lines rendered both lines HCVcc-permissive. We also found that the chimeric J6JFH1 construct, having the structure region from J6 isolate enhanced HCV replication in mouse hepatocytes rather than the full length original JFH1 construct, a new finding that suggests the possible role of the HCV structural region in HCV replication. This is the first report on the entry and replication of HCV infectious particles in mouse hepatocytes. These mouse hepatocyte lines will facilitate establishing a mouse HCV infection model with multifarious applications

    In Silico Analysis of the Apolipoprotein E and the Amyloid β Peptide Interaction: Misfolding Induced by Frustration of the Salt Bridge Network

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    The relationship between Apolipoprotein E (ApoE) and the aggregation processes of the amyloid β (Aβ) peptide has been shown to be crucial for Alzheimer's disease (AD). The presence of the ApoE4 isoform is considered to be a contributing risk factor for AD. However, the detailed molecular properties of ApoE4 interacting with the Aβ peptide are unknown, although various mechanisms have been proposed to explain the physiological and pathological role of this relationship. Here, computer simulations have been used to investigate the process of Aβ interaction with the N-terminal domain of the human ApoE isoforms (ApoE2, ApoE3 and ApoE4). Molecular docking combined with molecular dynamics simulations have been undertaken to determine the Aβ peptide binding sites and the relative stability of binding to each of the ApoE isoforms. Our results show that from the several ApoE isoforms investigated, only ApoE4 presents a misfolded intermediate when bound to Aβ. Moreover, the initial α-helix used as the Aβ peptide model structure also becomes unstructured due to the interaction with ApoE4. These structural changes appear to be related to a rearrangement of the salt bridge network in ApoE4, for which we propose a model. It seems plausible that ApoE4 in its partially unfolded state is incapable of performing the clearance of Aβ, thereby promoting amyloid forming processes. Hence, the proposed model can be used to identify potential drug binding sites in the ApoE4-Aβ complex, where the interaction between the two molecules can be inhibited

    A Soluble Acetylcholinesterase Provides Chemical Defense against Xenobiotics in the Pinewood Nematode

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    The pinewood nematode genome encodes at least three distinct acetylcholinesterases (AChEs). To understand physiological roles of the three pinewood nematode AChEs (BxACE-1, BxACE-2, and BxACE-3), BxACE-3 in particular, their tissue distribution and inhibition profiles were investigated. Immunohistochemistry revealed that BxACE-1 and BxACE-2 were distributed in neuronal tissues. In contrast, BxACE-3 was detected from some specific tissues and extracted without the aid of detergent, suggesting its soluble nature unlike BxACE-1 and BxACE-2. When present together, BxAChE3 significantly reduced the inhibition of BxACE-1 and BxACE-2 by cholinesterase inhibitors. Knockdown of BxACE-3 by RNA interference significantly increased the toxicity of three nematicidal compounds, supporting the protective role of BxACE-3 against chemicals. In summary, BxACE-3 appears to have a non-neuronal function of chemical defense whereas both BxACE-1 and BxACE-2 have classical neuronal function of synaptic transmission

    Low-Density Lipoprotein Receptor-Related Protein 1 (LRP1) Mediates Neuronal Aβ42 Uptake and Lysosomal Trafficking

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    Alzheimer's disease (AD) is characterized by the presence of early intraneuronal deposits of amyloid-beta 42 (Abeta42) that precede extracellular amyloid deposition in vulnerable brain regions. It has been hypothesized that endosomal/lysosomal dysfunction might be associated with the pathological accumulation of intracellular Abeta42 in the brain. Our previous findings suggest that the LDL receptor-related protein 1 (LRP1), a major receptor for apolipoprotein E, facilitates intraneuronal Abeta42 accumulation in mouse brain. However, direct evidence of neuronal endocytosis of Abeta42 through LRP1 is lacking.Here we show that LRP1 endocytic function is required for neuronal Abeta42 uptake. Overexpression of a functional LRP1 minireceptor, mLRP4, increases Abeta42 uptake and accumulation in neuronal lysosomes. Conversely, knockdown of LRP1 expression significantly decreases neuronal Abeta42 uptake. Disruptions of LRP1 endocytic function by either clathrin knockdown or by removal of its cytoplasmic tail decreased both uptake and accumulation of Abeta42 in neurons. Finally, we show that LRP1-mediated neuronal accumulation of Abeta42 is associated with increased cellular toxicity.These results demonstrate that LRP1 endocytic function plays an important role in the uptake and accumulation of Abeta42 in neuronal lysosomes. These findings emphasize the central function of LRP1 in neuronal Abeta metabolism
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