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Journal articles on the topic "A3J"
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McDonnell, Mollie M., Suzanne C. Karvonen, Amit Gaba, Ben Flath, Linda Chelico, and Michael Emerman. "Highly-potent, synthetic APOBEC3s restrict HIV-1 through deamination-independent mechanisms." PLOS Pathogens 17, no. 6 (2021): e1009523. http://dx.doi.org/10.1371/journal.ppat.1009523.
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The APOBEC3 (A3) genes encode cytidine deaminase proteins with potent antiviral and anti-retroelement activity. This locus is characterized by duplication, recombination, and deletion events that gave rise to the seven A3s found in primates. These include three single deaminase domain A3s (A3A, A3C, and A3H) and four double deaminase domain A3s (A3B, A3D, A3F, and A3G). The most potent of the A3 proteins against HIV-1 is A3G. However, it is not clear if double deaminase domain A3s have a generalized functional advantage to restrict HIV-1. In order to test whether superior restriction factors could be created by genetically linking single A3 domains into synthetic double domains, we linked A3C and A3H single domains in novel combinations. We found that A3C/A3H double domains acquired enhanced antiviral activity that is at least as potent, if not better than, A3G. Although these synthetic double domain A3s package into budding virions more efficiently than their respective single domains, this does not fully explain their gain of antiviral potency. The antiviral activity is conferred both by cytidine-deaminase dependent and independent mechanisms, with the latter correlating to an increase in RNA binding affinity. T cell lines expressing this A3C-A3H super restriction factor are able to control replicating HIV-1ΔVif infection to similar levels as A3G. Together, these data show that novel combinations of A3 domains are capable of gaining potent antiviral activity to levels similar to the most potent genome-encoded A3s, via a primarily non-catalytic mechanism.
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Takei, Hisashi, Masanori Fujii, Sohei Nakayama, et al. "Alternative Splicing of APOBEC3D Generates Functional Diversity and Its Role As a DNA Mutator." Blood 128, no. 22 (2016): 5107. http://dx.doi.org/10.1182/blood.v128.22.5107.5107.
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Abstract Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC) protein family consists of 11 members: APOBEC1, APOBEC2, seven APOBEC3s (A3s) (A/B/C/D/F/G/H), APOBEC4, and the activation-induced deaminase (AID). APOBEC1, A3s, and AID have cytidine deaminase activity and induce a cytidine (C) to thymidine (T) transition. The main function of A3s is to trigger an innate immune response to viral infection such as human immunodeficiency virus-1. Recently, it was reported that several APOBEC family proteins can induce somatic mutations into genomic DNA and thus promote cancer development. For example, AID-mediated somatic mutations contribute to B-cell lymphoma and A3B can be an enzymatic source in solid tumors such as breast cancer. However, little is known about other A3 member proteins. To determine the expression of A3 in hematopoietic cells, we performed quantitative PCR in leukemia cell lines. A3B, A3C, A3D, A3F and A3G were detected in all cell lines, but not A3A or A3H. Next, we analyzed published The Cancer Genome Atlas data from patients with acute myeloid leukemia to find somatic alterations in A3 genes using cBioPortal (http://www.cbioportal.org/). We found that each A3 was upregulated at 4-7 % of all samples and the total frequency of 23 %. Interestingly, overall survival of patients with A3upregulation was lower than those without upregulation, suggesting an important role of A3s in pathogenesis of leukemia. As it has been shown that A3A, A3B, and A3D show capacity to inflict DNA damage, we decided to investigate whether A3D can induce mutations in foreign and genomic DNA. During our attempt to generate A3D expression constructs, we detected multiple bands in leukemia and lung cancer cell lines. Based on our analysis and previous reports, we confirmed that there are at least 7 transcript variants (v1 to 7). Because A3D v3, v4 and v5 lack cytidine deaminase domains, we decided to examine A3Dv1, v2, v6 and v7. To determine whether A3D variants have foreign DNA editing activity, we performed differential DNA denaturation (3D)-PCR in HEK293T cells co-transfected with expression vectors for EGFP, UNG inhibitor, and pCAG-GS containing A3Dv1, v2, v6, v7, A3B or empty control. Total DNA was isolated 4 days after transfection. PCR products were detected at lower denaturation temperature (Td) in cells expressing A3B and all A3D variants vectors compared to control. Sequences of PCR products at lowest Td revealed that mutation frequencies in EGFP gene were 6.1-10.5 per 103 bps in cells transfected with all A3D variants and 18.7 per 103bps in cells transfected with A3B. Of note, 90 % of mutations were C/G to T/A transition in cells transfected with A3B, but in cells transfected with A3D these were 30-60 %. Next we performed 3D-PCR in HEK293T cells retrovirally infected with MigR1-IRES-EGFP containing A3Dv1, v2, v6, v7, A3B or empty to determine genomic DNA editing activity. Total DNA was isolated 4 weeks after infection. At lower Td, PCR products were detected only in cells expressing A3Dv1 and A3B. PCR products in cells expressing A3Dv2, v6, v7 were detected only at same Td as control. Sequences of the PCR products at lowest Td revealed that the mutation frequency in the EGFP gene was 22.2 per 103 bps in cells expressing A3Dv1, and 56.9 per 103 bps in cells expressing A3B. However mutation frequencies in cells expressing A3Dv6 or v7 were lower than 2 per 103bps and no mutations were detected in cells expressing A3Dv2. All of these mutations were C/G to T/A transition. Interestingly, we found 4 clones with deletion in cells expressing A3Dv1, v6 and A3B. In addition, all clones had several bases of micro homologous sequences in broken ends before joining. These results suggested that double strand breaks in genomic DNA were repaired by microhomology-mediated end joining. These DNA editing assays showed that all A3D variants had ability to induce mutations in foreign DNA, and A3Dv1 was major isoform which had ability to induce mutations in genomic DNA. Taken together, our experiments showed that A3D can be a DNA mutator and alternative splicing generates functional diversity of A3D. These findings suggest that A3D may contribute to development of hematopoietic malignancies. Disclosures Takaori-Kondo: Mochida Pharmaceutical: Research Funding; Astellas Pharma: Research Funding; Merck Sharp and Dohme: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Eisai: Research Funding; Takeda Pharmaceutical: Research Funding; Chugai Pharmaceutical: Research Funding; Alexion Pharmaceuticals: Research Funding; Kyowa Kirin: Research Funding; Pfizer: Research Funding; Janssen Pharmaceuticals: Speakers Bureau; Shionogi: Research Funding; Toyama Chemical: Research Funding; Cognano: Research Funding.
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Marin, Mariana, Sheetal Golem, Kristine M. Rose, Susan L. Kozak, and David Kabat. "Human Immunodeficiency Virus Type 1 Vif Functionally Interacts with Diverse APOBEC3 Cytidine Deaminases and Moves with Them between Cytoplasmic Sites of mRNA Metabolism." Journal of Virology 82, no. 2 (2007): 987–98. http://dx.doi.org/10.1128/jvi.01078-07.
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ABSTRACT VifIIIB, which has been a standard model for the viral infectivity factor of human immunodeficiency virus type 1 (HIV-1), binds the cytidine deaminase APOBEC3G (A3G) and induces its degradation, thereby precluding its lethal incorporation into assembling virions. Additionally, VifIIIB less efficiently degrades A3F, another potent anti-HIV-1 cytidine deaminase. Although the APOBEC3 paralogs A3A, A3B, and A3C have weaker anti-HIV-1 activities and are only partially degraded by VifIIIB, we found that VifIIIB induces their emigration from the nucleus to the cytosol and thereby causes net increases in the cytosolic concentrations and anti-HIV-1 activities of A3A and A3B. In contrast, some other Vifs, exemplified by VifHXB2 and VifELI-1, much more efficiently degrade and thereby neutralize all APOBEC3s. Studies focused mainly on A3F imply that it occurs associated with mRNA-PABP1 in translationally active polysomes and to a lesser extent in mRNA processing bodies (P-bodies). A3F appears to stabilize the P-bodies with which it is associated. A correspondingly small proportion of VifIIIB also localizes in P-bodies in an A3F-dependent manner. Stress causes A3A, A3B, A3C, and A3F to colocalize efficiently with VifIIIB and mRNA-PABP1 complexes in stress granules in a manner that is prevented by cycloheximide, an inhibitor of translational elongation. Coimmunoprecipitation studies suggest that Vifs from different HIV-1 isolates associate with all tested APOBEC3s. Thus, Vifs interact closely with structurally diverse APOBEC3s, with effects on their subcellular localization, degradation rates, and antiviral activities. Cytosolic APOBEC3-Vif complexes are predominantly bound to mRNAs that dynamically move between translationally active and storage or processing pools.
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Vasudevan, Ananda Ayyappan Jaguva, Sander H. J. Smits, Astrid Höppner, Dieter Häussinger, Bernd W. Koenig, and Carsten Münk. "Structural features of antiviral DNA cytidine deaminases." Biological Chemistry 394, no. 11 (2013): 1357–70. http://dx.doi.org/10.1515/hsz-2013-0165.
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Abstract The APOBEC3 (A3) family of cytidine deaminases plays a vital role for innate defense against retroviruses. Lentiviruses such as HIV-1 evolved the Vif protein that triggers A3 protein degradation. There are seven A3 proteins, A3A-A3H, found in humans. All A3 proteins can deaminate cytidines to uridines in single-stranded DNA (ssDNA), generated during viral reverse transcription. A3 proteins have either one or two cytidine deaminase domains (CD). The CDs coordinate a zinc ion, and their amino acid specificity classifies the A3s into A3Z1, A3Z2, and A3Z3. A3 proteins occur as monomers, dimers, and large oligomeric complexes. Studies on the nature of A3 oligomerization, as well as the mode of interaction of A3s with RNA and ssDNA are partially controversial. High-resolution structures of the catalytic CD2 of A3G and A3F as well as of the single CD proteins A3A and A3C have been published recently. The NMR and X-ray crystal structures show globular proteins with six α-helices and five β sheets arranged in a characteristic motif (α1-β1-β2/2′-α2-β3-α3-β4-α4-β5-α5-α6). However, the detailed arrangement and extension of individual structure elements and their relevance for A3 complex formation and activity remains a matter of debate and will be highlighted in this review.
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Talluri, Srikanth, Mehmet Kemal Samur, Leutz Buon, et al. "Dysregulated Aid/Apobec Family Proteins Promote Genomic Instability in Multiple Myeloma." Blood 128, no. 22 (2016): 803. http://dx.doi.org/10.1182/blood.v128.22.803.803.
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Abstract The AID/APOBEC family of cytidine deaminase proteins includes AID (activity induced deaminase), and 10 related APOBEC enzymes (A1, A2, A3A, A3B, A3C, A3D, A3F, A3G, A3H and A4). AID has been well-studied for its role in somatic hyper mutation and class switch recombination of immunoglobulin genes whereas APOBECs (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) have been shown to have roles in mRNA editing and in antiviral immunity. Dysregulated activity of APOBECs causes C >T transitions or C>G, C>A transversions in DNA. We have recently shown APOBEC signature mutation pattern in multiple myeloma (MM) genomes (Bolli et al Nat. Comm. 2014), and interestingly, the APOBEC mutation signature correlates with sub clonal diversity in myeloma. A role for the AID/APOBECs in generation of somatic mutations has also been proposed in a variety of other cancers based on identification of APOBEC signature mutations In order to understand which APOBECs are dysregulated in myeloma, we performed RNA sequencing analysis of primary myeloma cells from 409 newly-diagnosed MM patients and myeloma cell lines. Our analysis showed elevated expression of several APOBEC family members; mainly A3A, A3B, A3C, and A3G. We then optimized a plasmid-based functional assay and found high cytidine deaminase activity in extracts from a number of myeloma cell lines and patient derived CD138+ cells compared to CD138+ cells from healthy donors, suggesting that APOBECs are dysregulated in myeloma. We then investigated the impact of elevated APOBEC expression/function on overall genome maintenance and acquisition of genomic changes (such as amplifications, deletions) overtime. We used shRNA-mediated knockdown of specific APOBEC proteins in myeloma cell lines and investigated the acquisition of genomic changes in control and knockdown cells during their growth in culture, using SNP (Single Nucleotide Polymorphism) arrays and WGS (whole genome sequencing) platforms. Our results with both approaches showed significant reduction in the accumulation of copy number changes (both amplifications and deletions) and overall mutation load after APOBEC knockdown. Evaluation with both the SNP and WGS showed that when control and APOBEC knockdown cells were cultured for three weeks, the acquisition of new copy number and mutational changes throughout genome were reduced by ~50%. We next investigated the relationship between APOBEC expression/activity in MM and other DNA repair pathways. Using an in vitro HR activity assay, we measured HR activity in extracts from control and APOBEC knockdown cells. Depletion of APOBEC proteins resulted in 50-80% reduction in in vitro HR activity of the extracts. We also evaluated correlation between HR activity and gene expression using RNA-seq data from myeloma cells derived from 100 patients at diagnosis and identified the genes whose expression correlated with HR activity. Elevated expression of APOBECs 3D, 3G and 3F significantly correlated with high HR activity (R=0.3; P≤0.02), suggesting their relevance to HR. Analyzing genomic copy number information for each patient we have also observed significant correlation between higher expression of A3G and increased genomic instability in this dataset (P=0.0045). In summary, our study shows that dysregulated APOBECs induce mutations and genomic instability, and inhibiting APOBEC activity could reduce the rate of accumulation of ongoing genomic changes. This data sheds light on biology of the disease as well as clonal evolution. Disclosures Munshi: Amgen: Consultancy; Oncopep: Patents & Royalties; Celgene: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Merck: Consultancy; Pfizer: Consultancy.
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Pery, Erez, Kottampatty S. Rajendran, Andrew Jay Brazier, and Dana Gabuzda. "Regulation of APOBEC3 Proteins by a Novel YXXL Motif in Human Immunodeficiency Virus Type 1 Vif and Simian Immunodeficiency Virus SIVagm Vif." Journal of Virology 83, no. 5 (2008): 2374–81. http://dx.doi.org/10.1128/jvi.01898-08.
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ABSTRACT The APOBEC3 cytidine deaminases are potent antiviral factors that restrict the replication of human immunodeficiency virus type 1 (HIV-1). In HIV-1-infected CD4+ T cells, the viral accessory protein Vif binds to APOBEC3G (A3G), APOBEC3F (A3F), and APOBEC3C (A3C) and targets these proteins for polyubiquitination by forming an E3 ubiquitin ligase with cullin 5. Previous studies identified regions of HIV-1 Vif, 40YRHHY44 and 12QVDRMR17, which are important for interaction with A3G and A3F, respectively, and showed that Vif residues 54 to 71 are sufficient for A3G binding. Here, we identify 69YXXL72 as a novel conserved motif in HIV-1 Vif that mediates binding to human A3G and its subsequent degradation. Studies on other APOBEC3 proteins revealed that Tyr69 and Leu72 are important for the degradation of A3F and A3C as well. Similar to A3F, A3C regulation is also mediated by Vif residues 12QVDRMR17. Simian immunodeficiency virus (SIV) Vif was shown to bind and degrade African green monkey A3G (agmA3G) and, unexpectedly, human A3C. The YXXL motif of SIVagm Vif was important for the inactivation of agmA3G and human A3C. Unlike HIV-1 Vif, however, SIVagm Vif does not require Tyr40 and His43 for agmA3G degradation. Tyr69 in the YXXL motif was critical for binding of recombinant glutathione S-transferase-Vif(1-94) to A3G in vitro. These results suggest that the YXXL motif in Vif is a potential target for small-molecule inhibitors to block Vif interaction with A3G, A3F, and A3C, and thereby protect cells against HIV-1 infection.
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Atchekzaï, Jean, Bernard Bonnetot, Jean-Claude Duplan, Bernard Fenet, Bernard Ferage, and Henri Mongeot. "Unprecedented example of a3J(13C,11B) through a CCNB linkage." Magnetic Resonance in Chemistry 27, no. 7 (1989): 699–701. http://dx.doi.org/10.1002/mrc.1260270719.
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Nakashima, Masaaki, Shingo Kitamura, Teppei Kurosawa, et al. "Crystal structure of the Vif-interaction domain of the anti-viral APOBE3F." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C123. http://dx.doi.org/10.1107/s2053273314098763.
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Human cells express a family of cytidine deaminases, called APOBEC3 (A3) (A3A, B, C, D, F, G, and H). The family enzymes, especially A3G and A3F potentially inhibit replication of retroviruses including HIV-1. However, HIV-1 overcomes the A3-mediated antiviral system by expressing a virus-encoded antagonist, viral infectivity factor (Vif) protein. In HIV-1-infected cells, Vif specifically binds with A3 followed by proteasomal degradation of A3. Hence, inhibition of the interaction between A3 and Vif is an attractive strategy for developing novel anti-HIV-1 drugs. To date, we have determined the first crystal structure of A3 with Vif-binding interface, A3C (PDB ID: 3VOW). In addition, our extensive mutational analysis, based on the A3C structure, revealed that structural features of the Vif-binding interface are highly conserved among A3C, DE, and F [1]. However, more recently, Bohn et al. and Karen et al. have shown the crystal structures of mutant A3F C-terminal domain (CTD) which is responsible for the Vif interaction, and have predicted more extended area, including our identified residues, for the interface on the A3F CTD [2][3]. To clarify the Vif-binding interface of A3F, we sought to determine the crystal structure of the wild-type A3F CTD and evaluated contributions of the additional residues for the Vif-interaction interface by virological method. First, we have successfully determined the crystal structure of A3F CTD at 2.75 Å resolution. Furthermore, we have identified four additional residues unique on the A3F CTD but not A3C for Vif interaction, which are located in the vicinity of our previously reported interface. These results demonstrated that the structural features of Vif-binding interface are indeed conserved between A3C and A3F. Taken together, these results will provide the fine-tuned structure information to understand the binding between A3 and Vif and to facilitate a development of novel anti-HIV-1 compounds targeting A3 proteins.
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Wang, Feng-xiang, Jialing Huang, Hangxiang Zhang, Xinliang Ma, and Hui Zhang. "APOBEC3G upregulation by alpha interferon restricts human immunodeficiency virus type 1 infection in human peripheral plasmacytoid dendritic cells." Journal of General Virology 89, no. 3 (2008): 722–30. http://dx.doi.org/10.1099/vir.0.83530-0.
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APOBEC3G (A3G), a member of cytidine deaminase family, has potent anti-human immunodeficiency virus type 1 (HIV-1) activity. It has been demonstrated that alpha interferon (IFN-α) can significantly enhance the expression of A3G in human primary resting CD4+ T-cells, macrophages and primary hepatocytes, subsequently decreasing their viral susceptibility. Plasmacytoid dendritic cells (pDCs) are key effectors in innate host immunity, mediating adaptive immune responses and stimulating IFN-α production in reaction to various stimuli. In this report, we demonstrate that IFN-α, either exogenously added to- or endogenously secreted by pDCs, can enhance the expression of A3G and its family members such as A3A, A3C and A3F. We have also shown that IFN-α can inhibit HIV-1 expression in pDCs. This inhibitory effect could be countered by addition of an A3G-specific short interfering RNA, indicating that IFN-α-induced A3G plays a key role in mediating pDCs response to HIV-1. Given the central role played by pDCs in orchestrating the IFN-α/A3G intercellular network and intracellular signal pathway, our data indicate that pDCs themselves are also protected by an IFN-α/A3G-mediated innate immunity barrier from HIV-1 infection.
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Krisko, John F., Nurjahan Begum, Caroline E. Baker, John L. Foster, and J. Victor Garcia. "APOBEC3G and APOBEC3F Act in Concert To Extinguish HIV-1 Replication." Journal of Virology 90, no. 9 (2016): 4681–95. http://dx.doi.org/10.1128/jvi.03275-15.
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ABSTRACTThe multifunctional HIV-1 accessory protein Vif counters the antiviral activities of APOBEC3G (A3G) and APOBEC3F (A3F), and some Vifs counter stable alleles of APOBEC3H (A3H). Studies in humanized mice have shown that HIV-1 lacking Vif expression is not viable. Here, we look at the relative contributions of the three APOBEC3s to viral extinction. Inoculation of bone marrow/liver/thymus (BLT) mice with CCR5-tropic HIV-1JRCSF(JRCSF) expressing avifgene inactive for A3G but not A3F degradation activity (JRCSFvifH42/43D) displayed either no or delayed replication. JRCSF expressing avifgene mutated to inactivate A3F degradation but not A3G degradation (JRCSFvifW79S) always replicated to high viral loads with variable delays. JRCSF withvifmutated to lack both A3G and A3F degradation activities (JRCSFvifH42/43DW79S) failed to replicate, mimicking JRCSF without Vif expression (JRCSFΔvif). JRCSF and JRCSFvifH42/43D, but not JRCSFvifW79S or JRCSFvifH42/43DW79S, degraded APOBEC3D. With one exception, JRCSFs expressing mutant Vifs that replicated acquired enforcedvifmutations. These mutations partially restored A3G or A3F degradation activity and fully replaced JRCSFvifH42/43D or JRCSFvifW79S by 10 weeks. Surprisingly, induced mutations temporally lagged behind high levels of virus in blood. In the exceptional case, JRCSFvifH42/43D replicated after a prolonged delay with no mutations invifbut instead a V27I mutation in the RNase H coding sequence. JRCSFvifH42/43D infections exhibited massive GG/AG mutations inpolviral DNA, but in viral RNA, there were no fixed mutations in the Gag or reverse transcriptase coding sequence. A3H did not contribute to viral extinction but, in combination with A3F, could delay JRCSF replication. A3H was also found to hypermutate viral DNA.IMPORTANCEVif degradation of A3G and A3F enhances viral fitness, as virus with even a partially restored capacity for degradation outgrows JRCSFvifH42/43D and JRCSFvifW79S. Unexpectedly, fixation of mutations that replaced H42/43D or W79S in viral RNA lagged behind the appearance of high viral loads. In one exceptional JRCSFvifH42/43D infection,vifwas unchanged but replication proceeded after a long delay. These results suggest that Vif binds and inhibits the non-cytosine deaminase activities of intact A3G and intact A3F, allowing JRCSFvifH42/43D and JRCSFvifW79S to replicate with reduced fitness. Subsequently, enhanced Vif function is acquired by enforced mutations. In infected cells, JRCSFΔvif and JRCSFvifH42/43DW79S are exposed to active A3F and A3G and fail to replicate. JRCSFvifH42/43D Vif degrades A3F and, in some cases, overcomes A3G mutagenic activity to replicate. Vif may have evolved to inhibit A3F and A3G by stoichiometric binding and subsequently acquired the ability to target these proteins to proteasomes.
Dissertations / Theses on the topic "A3J"
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Jaguva, Vasudevan Ananda Ayyappan [Verfasser]. "APOBEC3 DNA deaminases: A mechanistic study of A3A, A3C, and A3G action on retroviruses and counteraction by viral proteins / Ananda Ayyappan Jaguva Vasudevan." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/1148720936/34.
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Domingues, Alexandre Enéas. "Estudo das alterações moleculares do gene ABO em doadores de sangue fenotipados como A3 e A3B." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5136/tde-01082007-141215/.
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O sistema sanguíneo ABO é o mais importante grupo sanguíneo na medicina transfusional. Atualmente, a determinação do tipo sanguíneo dos doadores de sangue é feita através de testes sorológicos rotineiros de laboratório, porém outros testes realizados com o DNA humano obtido de amostra de sangue, tornam-se complementos valiosos para a determinação correta do grupo sanguíneo do doador e do receptor, aumentando a segurança transfusional. Estudos realizados com o grupo sanguíneo A3 e A3B demonstraram que este subgrupo possui um alto grau de heterogeneidade, uma vez que diversos eventos moleculares foram associados a ele, embora apenas um pequeno número de amostras tenha sido testado até hoje. Nesse trabalho, foi investigada a frequência e os tipos de eventos moleculares do grupo sanguíneo A3 e A3B em um grupo de 100 doadores de sangue. Para seleção desse grupo foram analisadas 12.283 amostras de doadores de sangue saudáveis de ambos os sexos do grupo sanguíneo A e AB obtidas na Fundação Pró-Sangue/Hemocentro de São Paulo, pelos métodos teste em tubo e gel teste. Obtiveram-se 13 amostras A3 e 87 amostras A3B. Após extração e quantificação do DNA genômico das amostras utilizou-se amplificação do DNA pela técnica de reação da polimerase em cadeia alelo específico (PCR-ASP) para as regiões 467C>T, 829G>A, 871G>A e 1060C>A (del C) do exon 7 do gene ABO. Os resultados de amplificação das regiões estudadas apontam para um novo genótipo, aqui denominado A30*/ , presente em 30,7% das amostras A3 e em 58,6% das amostras A3B (A30*/B10*) (necessária a confirmação por sequenciamento); detectou-se também o genótipo A302/A301 em 30,7% das amostras A3 e o genótipo A302/B104 em 17,1% das amostras A3B; outros genótipos já descritos para subgrupo A3 (A301/A301, A302/A302, uma amostra de cada) foram também verificados bem como presença da mutação na região 871G>A em 9 amostras A3 ; verificou-se também que mutações nas regiões 467 C>T e 1060 C>A (del C), anteriormente descritas somente em indivíduos A2 e A2B, são muito frequentes em indivíduos A3 e A3B.<br>ABO blood system is the most important blood group in transfusional medicine. Actualy, the blood group type in blood donors and receptors is determined by serological laboratorial tests, complemented by human DNA blood tests that assure the correct blood group determination for the blood donor and receptor, optimizing transfusional safety. Studies on blood subgroup A3 e A3B demonstrated a large subgroup heterogenity, with various associated molecular changes in small sample groups tested. At present study, it was proposed investigation about the frequency and the types of molecular alterations occuring among 100 blood donors samples phenotyped as A3 e A3B. These samples are selected after tub and gel tests analysis of 12.283 A and AB samples of healthy blood donors of both sex from Fundação Pró-Sangue/Hemocentro de São Paulo. Thirteen A3 and 87 A3B samples were selected, each sample genomic DNA was extracted and quantified and it was performed DNA amplification by alellic specific polimerase chain reaction (PCR-ASP). It was studied exon 7 ABO gene mutations 467C>T, 829G>A, 871G>A and 1060C>A (del C). Amplification results pointed that a new genotipe is present at these A3 and A3B subgroup, named in this study as the A30*/ genotipe (sequencing confirmation needed); these genotipe is present in 30.7% A3 samples and in 58.6% A3B samples (A30*/B10*). However, it was detected the ulterior decrived genotipes: A302 present in 30.7% A3 samples (A302/A301) and in 17.1% A3B samples (A302/B104); for subgroup A3 it was observed the genotipes A301/A301, A302/A302 (one sample each) and the presence of 871G>A mutation at 9 A3 samples; 467 C>T and 1060 C>A (del C) exon 7 ABO gene mutations descrived at A2 e A2B samples, are very frequents at these A3 e A3B samples tested.
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Macaluso, Nicholas-Jacomo Maximilian. "Studies on the apelin/APJ system." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609383.
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Nishihara, Anderson. "Montagem assistida por realidade aumentada (A3R)." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-28092016-105248/.
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Processos de montagem em geral necessitam de instruções para serem executados, desde a montagem de simples brinquedos até máquinas complexas. Tradicionalmente, essas instruções vem na forma de manuais em papel ou meio digital. Seja qual for o modo, os manuais de instruções utilizam desenhos, diagramas ou fotos, além de instruções textuais para indicar a sequência de montagem do início até o estado final. Procurando mudar esse paradigma, esse trabalho propõe um sistema para auxílio à montagem que utiliza realidade aumentada para guiar o usuário no processo. Através de processamento de imagens capturadas por uma câmera o sistema reconhece cada peça e por meio de sinais gráficos é indicado ao usuário qual a peça a ser manipulada e onde deve ser posicionada. Em seguida é feito a verificação do posicionamento das peças e o usuário é alertado quando a tarefa de montagem atinge o estado final. Muitos trabalhos na área utilizam algum tipo de dispositivo customizado como \"head mounted display\" (HMD) e marcadores para auxiliar o rastreamento da câmera e identificação das peças, limitando a popularização dessa tecnologia. Tendo esse último ponto em vista, propõe-se um sistema que não utiliza qualquer dispositivo customizado ou marcadores para rastreamento. Além disso, todos os processos do sistema são executados em software embarcado, não necessitando de comunicação com outros computadores para o processamento de imagens. Como o sistema não faz uso de marcadores para a identificação das peças, inicialmente é proposto a implementação do sistema para guiar o usuário na resolução de um quebra-cabeças plano. O sistema proposto é denominado como MARA (Montagem Assistida por Realidade Aumentada).<br>Assembly processes for simple toys or complex machines usually requires instructions to be executed. Traditionally, these instructions are written in the form of paper or digital manuals. These manuals contains descriptive text, photos or diagrams to guide the assembly sequence from the beginning to the final state. To change this paradigm, it is proposed in this work an augmented reality system to guide assembly tasks. The system recognizes each assembly piece through image processing techniques and guides the piece placement with graphic signals. Later, the system checks if the pieces are properly assembled and warns the user when the assembly have been finished. In the field of assembly assisted by augmented reality systems, many works use some kind of customized device, like head mounted displays (HMD). Furthermore, markers have been used to track camera position and identify assembly parts. These two features restrict the spread of the technology, thus in the proposed work customized devices and markers to track and identify parts shall not be used. Besides, all the processing are executed on embedded software without the need of communication with other computers to help image processing. The first implementation of the proposed system assists the user on the assembly of a planar puzzle, as the proposed system do not use markers to recognize assembly pieces. This system is being called A3R (Assembly Assisted by Augmented Reality).
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Lafrance, Mylène. "Relation structure-activité, distribution et fonctions des récepteurs couplés aux protéines G : NTS2 et APJ." Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5396.
Full textAbstract:
Les récepteurs couplés aux protéines G (RCPG) de classe A sont les cibles de plus de 25% des médicaments sur le marché et nombreux sont ceux impliqués dans le traitement de la douleur. Les enjeux dans les traitements de la douleur chronique est énorme puisque nombreux sont ceux qui ne répondent pas à la médication usuelle. La recherche de nouvelles avenues thérapeutiques est indispensable afin d’aider les patients dont le soulagement est limité. Le récepteur de la neurotensine de type 2 (NTS2) et le récepteur APJ de l’apéline sont deux RCPG qui pourraient être des cibles pour deux éventuels traitements contre la douleur. Les objectifs de cette thèse étaient de caractériser des analogues synthétiques ciblant les récepteurs NTS2 ou APJ, examiner la distribution de ces récepteurs dans le cerveau, la moelle épinière et les ganglions spinaux pour ensuite déterminer leur implication dans la régulation du contrôle descendant au niveau spinal et supraspinal dans la région bulbaire rostro-ventrale (RVM) en conditions de douleurs aiguë et tonique. Nous avons observé que l’immunoréactivité du récepteur NTS2 était distribuée dans l’axe rostrocaudal de la substance grise périaqueductal (SGPA) et dans tous les noyaux de la RVM. Les résultats sont similaires avec l’anticorps anti-APJ démontrant que ces deux récepteurs sont impliqués dans le contrôle de la douleur. Aussi, les résultats en immunohistochimie dans la moelle épinière ont illustré la présence du récepteur APJ dans les laminae superficielles. Dans les ganglions spinaux, APJ colocalise dans les neurones substance P. Les résultats aux tests comportementaux avec administration intra-RVM d’analogues modifiés neurotensinergiques ont montré une analgésie impliquée par l’activation de NTS2 dans la RVM. L’analgésie provoquée par le récepteur NTS2 serait médiée via la relâche de sérotonine au niveau de la moelle épinière en conditions de douleurs aiguë et tonique. Les résultats en douleur tonique avec les analogues Apeline-13 modifiés en position carboxy-terminale illustrent que les modifications comportant les groupements 2-naphtalenalanine (2 Nal) et de l’acide aminoisobutyrique (Aib) permettent une plus forte analgésie générale, cependant nos expériences à ce jour ne nous permettent pas de statuer sur les différentes voies de signalisation activées dans ces conditions. La modélisation moléculaire pourrait nous aider davantage afin d’explorer les différentes caractéristiques des ligands biaisés. Ces études sur la relation structure-activité, distribution et fonctions des récepteurs NTS2 et APJ dans la modulation de douleur ne sont qu’un début vers des nouveaux traitements contre la douleur.
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Vignola, Alex. "Abrasive water jet (AWJ): tecnologia, impianto e ruolo dell’abrasivo." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Find full textAbstract:
La tecnologia water jet è una tecnologia piuttosto recente che però, negli ultimi decenni, ha avuto uno sviluppo davvero elevato; uno sviluppo continuo, a partire dagli anni 50, che non accenna ad arrestarsi, e che ha progressivamente migliorata la tecnologia, portandola ad essere una delle più versatili presenti sul mercato odierno. All’inizio fu utilizzata su materiali morbidi e con spessori limitati, come carta o plastica. La successiva introduzione dell’abrasivo, in aggiunta al getto d’acqua pressurizzato, ha portato alla possibilità di lavorare materiali e spessori di interesse ingegneristico.
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Steyn, Abraham Jacobus. "Karakterisering en evaluering van 'n hidrouliese enjinmonteerstuk / Steyn A.J." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7571.
Full textAbstract:
The engine mount system is an important aspect to achieve vibration isolation, and has a very important effect on the ride standards and noise in a vehicle's compartment. In this study a hydraulic engine mount was designed and built and two mathematical models were developed. The first mathematical model was used to determane the dynamic properties of the hydraulic engine mount as well as the rubber engine mountings for various frequencies and amplitudes. The dynamic properties were determined in a test assembly that was designed and build for this application. These dynamic properties were used to evaluate the vibration isolation. The second mathematical model was a two degree of freedom model that was developed and implemented in a computer programme in a Matlab environment. This programme was used to predict the natural frequencies for the vertical bounce and rotational mode by using the dynamic properties of the engine mountings. This second model was also used to predict the engine response and dynamic forces transmitted to the vehicle structure with the help of a computer program. The engine unbalance forces and fluctuating moments were determined with the use of certain parameters. The engine mass and the moment of inertia, as well as the coordinates and dynamic properties of the three engine mountings, were also determined and used as input in the computer programme. The predicted engine response was compared with corresponding measured values for the same conditions. The engine mountings must also be able to support the static weight of the engine, with allowable displacement at each mount. The static and dynamic displacement was determined for various operating conditions.
Two engine mounting systems were evaluated in the test vehicle. The standard engine mounting system consists of three rubber engine mountings. The modified mounting system has two rubber mounts that were replaced with hydraulic engine mounts. Response measurements were taken on each of the engine mounting systems in the vertical direction respectively. The dynamic forces transmitted to the vehicle structure were determined and compared for the two mounting systems, by using this measured values as well as the mounting dynamic properties for different operational conditions. Sound measurements inside the vehicle cabin were also measured separately for the two mounting systems and compared with each other. This study shows that the hydraulic engine mount has a big improvement on the isolation system, and that the biggest benefit was at road inputs as operational conditions.<br>Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Robla, Sánchez Ignacio. "Wheel Wear Simulation of the Light Rail Vehicle A32." Thesis, KTH, Spårfordon, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-261228.
Full textAbstract:
During the last decade, a novel methodology for wheel wear simulation has been developed in Sweden. The practical objective of this simulation procedure is to provide an integratedengineering tool to support rail vehicle design with respect to wheel wear performance and detailed understanding of wheel-rail interaction. The tool is integrated in a vehicle dynamicssimulation environment.The wear calculation is based on a set of dynamic simulations, representing the vehicle, the network, and the operating conditions. The wheel profile evolution is simulated in an iterativeprocess by adding the contribution from each simulation case and updating the profile geometry.The method is being validated against measurements by selected pilot applications. To strengthen the confidence in simulation results the scope of application should be as wide aspossible in terms of vehicle classes. The purpose of this thesis work has been to try to extend the scope of validation of this method into the light rail area, simulating the light rail vehicleA32 operating in Stockholm commuter service on the line Tvärbanan.An exhaustive study of the wear theory and previous work on wear prediction has been necessary to understand the wear prediction method proposed by KTH. The dynamicbehaviour of rail vehicles has also been deeply studied in order to understand the factors affecting wear in the wheel-rail contact.The vehicle model has been validated against previous studies of this vehicle. Furthermore new elements have been included in the model in order to better simulate the real conditionsof the vehicle.Numerous tests have been carried out in order to calibrate the wear tool and find the settings which better match the real conditions of the vehicle.Wheel and rail wear as well as profile evolution measurements were available before this work and they are compared with those results obtained from the simulations carried out.The simulated wear at the tread and flange parts of the wheel match quite well the measurements. However, the results are not so good for the middle part, since themeasurements show quite evenly distributed wear along the profile while the results from simulations show higher difference between extremes and middle part. More tests would benecessary to obtain an optimal solution.
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Hubinger, Adriaan Johannes. "An appropriate leadership model for the banking industry / Hubinger A.J." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7362.
Full textAbstract:
This study aims to measure the managerial skills of managers working in the
banking industry. To do so, the newly developed managerial skills measuring
instrument of Thekiso (2011) was used by to determine skills for managerial
competence in the banking industry. The seven managerial skills that are covered in
the questionnaire are: Self awareness skills; Self directed career planning;
Integrative skills; Planning and controlling skills; Organizing skills; Leading skills;
and Managing change skills.
Even though some skills may appear on a less frequent basis, six of the seven skills
were rated to be of a high importance, with their means ranging between 4.008 and
4.480 on the 5–point Likert scale. Training in the form of mentoring and stewardship
programs, to transfer knowledge and introduce existing relationships to up and
coming leaders, would be of great value for companies in the banking industry to
foster these seven managerial competency skills. By implementing training and
mentoring programs on a much broader scale, organisations can train and use their
leaders’ abilities to gain competitive advantage in the market.<br>Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.
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Laranjeira, Hugo Miguel Marque. "Alternativa à transfusão homóloga, nas cirurgias ortopédicas ATJ e ATA." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9660.
Full textAbstract:
Mestrado em Bioquímica<br>As cirurgias ortopédicas, como a artroplastia total do joelho (ATJ) e a
artroplastia total da anca (ATA) são responsáveis por grande perda de sangue,
sendo necessário recorrer frequentemente a transfusões homólogas para a
compensar. No entanto, para além das transfusões homólogas não serem
isentas de riscos, são um recurso limitado e caro. Assim, como forma de
reduzir as necessidades de transfusões homólogas, tem-se desenvolvido
várias estratégias alternativas. A utilização de dispositivos que permitem a
recuperação do sangue drenado do local cirúrgico e a sua reinfusão depois de
filtrado está na base de uma dessas estratégias. No Centro Hospitalar do
Baixo Vouga, E.P.E. – Aveiro recorre-se a esta abordagem usando os
dispositivos Cell Trans™.
O presente trabalho teve por objetivo verificar a eficácia do Cell Trans™
na ATJ e na ATA. Foram realizados dois estudos: A. Eficácia dos Cell Trans™
na ATJ e na ATA – um estudo retrospetivo e B. Eficácia da utilização do Cell
Trans™ em pacientes submetidos a ATJ – um estudo prospetivo randomizado.
No estudo A, com a implementação do Cell Trans™ 29% dos pacientes
submetidos a ATJ e 38% dos pacientes submetidos a ATA receberam
transfusão homóloga de concentrado de eritrócitos (CE), um número
significativamente menor ao observado antes da sua implementação, 68% e
59%, respetivamente. Concomitantemente, verificou-se uma redução no tempo
de internamento e um aumento nas unidades de CE pedidas e posteriormente
devolvidas com a utilização destes dispositivos. No estudo B verificou-se que a
utilização destes dispositivos mantém os pacientes com níveis de hemoglobina
acima do limiar de transfusão, não exercendo efeitos significativos nas
contagens de leucócitos e plaquetas. No entanto, aumentou o volume médio
de sangue drenado de 1038mL para 1572mL em 48 horas, sendo reinfundidos
em média 1089mL de sangue.
Este estudo sugere que a utilização do Cell Trans™ no Centro Hospitalar
Baixo Vouga, E.P.E. – Aveiro é uma prática positiva, reduzindo
significativamente a necessidade de transfusão de CE e o tempo de
internamento dos pacientes, sendo que a reinfusão de sangue recuperado do
local cirúrgico com Cell Trans™ apresenta efeitos semelhantes à transfusão de
CE. Estudos futuros envolvendo a análise de parâmetros bioquímicos
indicativos de processos como ativação da coagulação, ativação da fibrinólise,
ativação de leucócitos e ativação de plaquetas serão importantes para suportar
a utilização com segurança deste dispositivo na prática clínica.<br>As cirurgias ortopédicas, como a artroplastia total do joelho (ATJ) e a
artroplastia total da anca (ATA) são responsáveis por grande perda de sangue,
sendo necessário recorrer frequentemente a transfusões homólogas para a
compensar. No entanto, para além das transfusões homólogas não serem
isentas de riscos, são um recurso limitado e caro. Assim, como forma de
reduzir as necessidades de transfusões homólogas, tem-se desenvolvido
várias estratégias alternativas. A utilização de dispositivos que permitem a
recuperação do sangue drenado do local cirúrgico e a sua reinfusão depois de
filtrado está na base de uma dessas estratégias. No Centro Hospitalar do
Baixo Vouga, E.P.E. – Aveiro recorre-se a esta abordagem usando os
dispositivos Cell Trans™.
O presente trabalho teve por objetivo verificar a eficácia do Cell Trans™
na ATJ e na ATA. Foram realizados dois estudos: A. Eficácia dos Cell Trans™
na ATJ e na ATA – um estudo retrospetivo e B. Eficácia da utilização do Cell
Trans™ em pacientes submetidos a ATJ – um estudo prospetivo randomizado.
No estudo A, com a implementação do Cell Trans™ 29% dos pacientes
submetidos a ATJ e 38% dos pacientes submetidos a ATA receberam
transfusão homóloga de concentrado de eritrócitos (CE), um número
significativamente menor ao observado antes da sua implementação, 68% e
59%, respetivamente. Concomitantemente, verificou-se uma redução no tempo
de internamento e um aumento nas unidades de CE pedidas e posteriormente
devolvidas com a utilização destes dispositivos. No estudo B verificou-se que a
utilização destes dispositivos mantém os pacientes com níveis de hemoglobina
acima do limiar de transfusão, não exercendo efeitos significativos nas
contagens de leucócitos e plaquetas. No entanto, aumentou o volume médio
de sangue drenado de 1038mL para 1572mL em 48 horas, sendo reinfundidos
em média 1089mL de sangue.
Este estudo sugere que a utilização do Cell Trans™ no Centro Hospitalar
Baixo Vouga, E.P.E. – Aveiro é uma prática positiva, reduzindo
significativamente a necessidade de transfusão de CE e o tempo de
internamento dos pacientes, sendo que a reinfusão de sangue recuperado do
local cirúrgico com Cell Trans™ apresenta efeitos semelhantes à transfusão de
CE. Estudos futuros envolvendo a análise de parâmetros bioquímicos
indicativos de processos como ativação da coagulação, ativação da fibrinólise,
ativação de leucócitos e ativação de plaquetas serão importantes para suportar
a utilização com segurança deste dispositivo na prática clínica.
Books on the topic "A3J"
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Wuppuluri, Shyam, and Newton da Costa, eds. WITTGENSTEINIAN (adj.). Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-27569-3.
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Markaz-i ʻUlūm-i Islāmiyah (Karachi, Pakistan), ред. Auj-i Ẓamīr. Markaz-i ʻUlūm-i Islāmiyah, 2014.
Find full textBook chapters on the topic "A3J"
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Huntley, Jim S. "A30 Tourniquets." In Basic Techniques in Pediatric Surgery. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-20641-2_30.
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"Sonstige bakterielle Krankheiten mit generalisierten Manifestationen [A30–A32, A35]." In Kurzlehrbuch Medizinische Mikrobiologie und Infektiologie, edited by Uwe Groß. Georg Thieme Verlag, 2013. http://dx.doi.org/10.1055/b-0034-96693.
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Newnham, Robert E. "Transformations." In Properties of Materials. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198520757.003.0004.
Full textAbstract:
Many physical properties depend on direction and the resulting anisotropy is best described with the use of tensors. Tensors are classified according to how they transform from one coordinate system to another. Therefore, we begin by describing transformations. There are several reasons why we want to do this: (1) transformations help us define tensors, (2) these tensors can be used to describe physical properties, (3) the effects of symmetry on physical properties can be determined by howthe tensor transforms under a symmetry operation, (4) the magnitude of a property in any arbitrary direction can be evaluated by transforming the tensor, (5) using these numbers, we can draw a geometric representation of the property, and (6) the transformation procedure provides a way of averaging the properties over direction. This is useful when relating the properties of polycrystalline materials to those of the single crystal. Mathematically, there is nothing fancy about these transformations. We are simply converting one set of orthogonal axes (Z1, Z2, Z3) into another (Z'1, Z'2, Z'3). The two sets of axes are related to one another by nine direction cosines: a11, a12, a13, a21, a22, a23, a31, a32, and a33. Collectively all nine can be written as aij where i, j = 1, 2, 3. The axes and direction cosines are illustrated in Fig. 2.1. It is important not to confuse the subscripts of the direction cosines. As defined in the drawing, a12 is the cosine of the angle between Z'1 and Z2, whereas a21 is the cosine of the angle between Z'2 and Z1. The first subscript always refers to the “new” or transformed axis. The second subscript is the “old” or original axis. The original or starting axes is usually a right-handed set, but it need not be. The transformed “new” axes may be either right- or left-handed, depending on the nature of the transformation. This will become clearer when we look at some transformations representing various symmetry operations. In any case, both the old and new axes are orthogonal.
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"Other lesions (Figures A30-A35)." In Handbook of Dermoscopy. CRC Press, 2006. http://dx.doi.org/10.1201/b14613-11.
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"A3a." In Encyclopedia of Signaling Molecules. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_100073.
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"A30." In Drawn after Nature. KNNV Publishing, 2008. http://dx.doi.org/10.1163/9789004278004_042.
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Siddiqui, Tauseef Uddin, and Mukul Shukla. "Modeling and Optimization of Abrasive Water Jet Cutting of Kevlar Fiber-Reinforced Polymer Composites." In Computational Methods for Optimizing Manufacturing Technology. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0128-4.ch011.
Full textAbstract:
This chapter presents a detailed study of abrasive water jet (AWJ) cutting of thin and thick Kevlar fiber-reinforced polymer (FRP) composites used in transport aircraft and anti-ballistic applications. Kevlar composites are considered to be very challenging to machine using traditional techniques. Most of the research conducted in the area of AWJ cutting has been limited to single response optimization. However, in real life machining, the performance of a process/product demands multi-objective optimization (MOO). No work has been reported till now using different MOO techniques for AWJ cutting of Kevlar FRP composites. Experimental modeling of depth of cut and various design of experiments based single and multi-objective optimization studies are presented here. Statistical analysis of variance has been performed to rank the different process parameters and estimate their effects on various AWJ cut kerf quality characteristics. The studies conducted in this chapter are likely to prove beneficial to the AWJ community in performing modeling and simultaneous optimization of multiple quality characteristics.
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"Supervision A34." In The W. R. Bion Tradition, edited by Howard B. Levine and Giuseppe Civitarese. Routledge, 2018. http://dx.doi.org/10.4324/9780429483738-8.
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"WAGNER A.J." In Hydraulicians in the USA 1800-2000. CRC Press, 2015. http://dx.doi.org/10.1201/b18854-459.
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"ACKERMAN A.J." In Hydraulicians in the USA 1800-2000. CRC Press, 2015. http://dx.doi.org/10.1201/b18854-7.
Full textConference papers on the topic "A3J"
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Mei, Le, Junbao Zhang, Yifeng Huang, et al. "Investigation on Deposited Metal Properties of Homemade Nickel and Nickel-Free Electrodes and Fluxes for Submerged Arc Welding of SA-508 Gr.3 Cl.1." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66331.
Full textAbstract:
Up to now, two kinds of filler metal with or without nickel element for submerged arc welding have been largely used in the reactor pressure vessel (RPV) manufacturing. In order to study the effect of nickel element on weld metal properties of SA-508 Gr.3 Cl.1, submerged arc welding material with nickel (AWS classification F8P4-EGN-F2N, F2 for short) and welding material without nickel (F8P4-EA3N-A3N, A3 for short) were used; and conventional mechanical properties, low-cycle fatigue test, and proton irradiation analysis of the two weld metals were studied. Results show that the mechanical properties of the two different weld metals are similar, except that the Charpy V-notch impact property of the weld metal with nickel is better than that without nickel; the micro-structures of F2 and A3 weld metals are both composed of ferrite base and granular bainite, but the columnar grain size of F2 weld metal is smaller relatively, which results in better impact property. In addition, the irradiated A3 weld metal has fewer dislocation loops than the irradiated F2 weld metal after the same proton irradiation dose; the irradiated weld metals both have higher micro-Vickers hardness than before.
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Squicciarini, Anna Cinzia, Smitha Sundareswaran, Dan Lin, and Josh Wede. "A3P." In the 22nd ACM conference. ACM Press, 2011. http://dx.doi.org/10.1145/1995966.1996000.
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Louahed, Jamila, Frederic Lehmann, Fernando Ulloa‐Montoya, et al. "Abstract A37: Identification of a gene expression signature predictive of clinical activity following MAGE‐A3 ASCI treatment." In Abstracts: AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics--Nov 15-19, 2009; Boston, MA. American Association for Cancer Research, 2009. http://dx.doi.org/10.1158/1535-7163.targ-09-a37.
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Nwaonumah, Ezebuugo, and Biswanath Samanta. "Visual Navigation of Wheeled Mobile Robots Using Deep Reinforcement Learning: Simulation to Real-Time Implementation." In ASME 2020 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/dscc2020-3279.
Full textAbstract:
Abstract A study is presented on applying deep reinforcement learning (DRL) for visual navigation of wheeled mobile robots (WMR), both in simulation and real-time implementation under dynamic and unknown environments. The policy gradient based asynchronous advantage actor critic (A3C), has been considered. RGB (red, green and blue) and depth images have been used as inputs in implementation of A3C algorithm to generate control commands for autonomous navigation of WMR. The initial A3C network was generated and trained progressively in OpenAI Gym Gazebo based simulation environments within robot operating system (ROS) framework for a popular target WMR, Kobuki TurtleBot2. A pre-trained deep neural network ResNet50 was used after further training with regrouped objects commonly found in laboratory setting for target-driven visual navigation of Turlebot2 through DRL. The performance of A3C with multiple computation threads (4, 6, and 8) was simulated and compared in three simulation environments. The performance of A3C improved with number of threads. The trained model of A3C with 8 threads was implemented with online learning using Nvidia Jetson TX2 on-board Turtlebot2 for mapless navigation in different real-life environments. Details of the methodology, results of simulation and real-time implementation through transfer learning are presented along with recommendations for future work.
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"A3L-C RF Oscillators." In 2008 15th IEEE International Conference on Electronics, Circuits and Systems. IEEE, 2008. http://dx.doi.org/10.1109/icecs.2008.4675148.
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"A3L-D Embedded Systems." In 2008 15th IEEE International Conference on Electronics, Circuits and Systems. IEEE, 2008. http://dx.doi.org/10.1109/icecs.2008.4675149.
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Liu, H. T., Y. Hovanski, and M. E. Dahl. "Machining of Aircraft Titanium With Abrasive-Waterjets for Fatigue Critical Applications." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25063.
Full textAbstract:
Laboratory tests were conducted to determine the fatigue performance of AWJ-machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results of the titanium specimens not only confirmed our previous findings in aluminum dog-bone specimens but in comparison also further enhanced the fatigue performance of the titanium. In addition, titanium is known to be difficult to cut, particularly for thick parts, however AWJs cut the material 34% faster than stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred combination for processing aircraft titanium that is fatigue critical.
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Liu, H. T., Y. Hovanski, M. E. Dahl, and J. Zeng. "Applications of Abrasive-Waterjets for Machining Fatigue-Critical Aerospace Aluminum Parts." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77003.
Full textAbstract:
Current specifications require AWJ-cut aluminum parts for fatigue critical aerospace structures to go through subsequent processing due to concerns of degradation in fatigue performance. The requirement of secondary process for AWJ-machined parts greatly negates the cost effectiveness of waterjet technology. Some cost savings are envisioned if it can be shown that AWJ net cut parts have comparable durability properties as those conventionally machined. To revisit and upgrade the specifications for AWJ machining of aircraft aluminum, “Dog-bone” specimens, with and without secondary processes, were prepared for independent fatigue tests at Boeing and Pacific Northwest National Laboratory (PNNL). Test results show that the fatigue life is proportional to quality levels of machined edges or inversely proportional to the surface roughness Ra. Even at highest quality level, the average fatigue life of AWJ-machined parts is about 30% shorter than those of conventionally machined counterparts. Between two secondary processes, dry-grit blasting with aluminum oxide abrasives until the striation is removed visually yields excellent result. It actually prolongs the fatigue life of parts at least three times higher than that achievable with conventional machining. Dry-grit blasting is relatively simple and inexpensive to administrate and, equally important, alleviates the concerns of garnet embedment.
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Sadasivam, Balaji, Alpay Hizal, and Dwayne Arola. "Abrasive Waterjet Peening With Elastic Prestress: Subsurface Residual Stress Distribution." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43473.
Full textAbstract:
Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.
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"A3L-B Security and Cryptography." In 2008 15th IEEE International Conference on Electronics, Circuits and Systems. IEEE, 2008. http://dx.doi.org/10.1109/icecs.2008.4675147.
Full textReports on the topic "A3J"
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Hutzler, Scott A. Alcohol-to-Jet (ATJ) Fuel Blending Study. Defense Technical Information Center, 2015. http://dx.doi.org/10.21236/ad1001842.
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Evens, T., S. Bayraktar, P. Lucente, P. Mi, and S. Zhuang. Support for Adj-RIB-Out in the BGP Monitoring Protocol (BMP). RFC Editor, 2019. http://dx.doi.org/10.17487/rfc8671.
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Ravindranath, N. H., A. Meili, and R. Anita. AIJ in the Non-Energy Sector in India: Opportunities and Concerns. Office of Scientific and Technical Information (OSTI), 1998. http://dx.doi.org/10.2172/6482.
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Yost, Douglas M., and Edwin A. Frame. GEP 6.5LT Engine Cetane Window Evaluation for ATJ/JP-8 Fuel Blends. Defense Technical Information Center, 2015. http://dx.doi.org/10.21236/ad1001846.
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Smith, S. M. The Meta-Lax method of stress reduction in welds. [ASTM A36; AISI 4140]. Office of Scientific and Technical Information (OSTI), 1992. http://dx.doi.org/10.2172/7166039.
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Bunce G. M. A3 line tune/beam line information. Office of Scientific and Technical Information (OSTI), 1985. http://dx.doi.org/10.2172/1157435.
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Goheen, S. D., M. McCulloch, and J. L. Daniel. Hanford environmental analytical methods (methods as of March 1990). Appendix A3-O and Appendix A3-I. Office of Scientific and Technical Information (OSTI), 1993. http://dx.doi.org/10.2172/10103265.
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Elderd, R. K., and G. Chasin. Army Awards Analysis (A3) Study. Volume 2. Reserve Components. Defense Technical Information Center, 1985. http://dx.doi.org/10.21236/ada159704.
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Corcoran, Patrick E. Gunner Tracking Models for the BFVS-A3 Combat Vehicle Engineering Simulation. Defense Technical Information Center, 2001. http://dx.doi.org/10.21236/ada396834.
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Hunn, John, and Michael Trammell. Data Compilation for AGC-2 Matrix-only Compact Lot A3-P33. Office of Scientific and Technical Information (OSTI), 2010. http://dx.doi.org/10.2172/1649085.
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