1,011 research outputs found
Predicting wear of UHMWPE: decreasing wear rate following a change in direction
No full textComputational tools are emerging as design tools for the development of total joint replacement with improved wear performance. The current wear models of polyethylene assume that wear is linearly proportional to sliding distance; however, it is hypothesized that the wear rate varies and is higher near a change in direction, but diminishes with continued unidirectional sliding, which eventually exhibits negligible wear. Our goals were to (1) reveal the presence of a variable wear rate in polyethylene; (2) identify the sliding distance required to reestablish unidirectional sliding subsequent to a change in sliding direction. The wear of polyethylene was evaluated in pin-on-disk testing for several different sliding distances (0 mm, 1 mm, 2 mm, 5 mm, 10 mm, and 100 mm) after a 90° change in direction. The results indicate the wear rate immediately following the change in direction is high, but with continued linear sliding the wear rate appears to drop to near zero--returning to the low wearing condition of unidirectional sliding. Furthermore, this transition appears to occur nonlinearly below 5 mm from the change in direction. While more studies are required to explore other paths and uncover the underlying mechanisms, these results should aid the development of computational tools for the design of advanced joint replacement
A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences within the Ventral Striatum
No full textMany children born preterm exhibit frontal executive dysfunction, behavioral problems including attentional deficit/hyperactivity disorder and attention related learning disabilities. Anomalies in regional specificity of cortico-striato-thalamo-cortical circuits may underlie deficits in these disorders. Nonspecific volumetric deficits of striatal structures have been documented in these subjects, but little is known about surface deformation in these structures. For the first time, here we found regional surface morphological differences in the preterm neonatal ventral striatum. We performed regional group comparisons of the surface anatomy of the striatum (putamen and globus pallidus) between 17 preterm and 19 term-born neonates at term-equivalent age. We reconstructed striatal surfaces from manually segmented brain magnetic resonance images and analyzed them using our in-house conformal mapping program. All surfaces were registered to a template with a new surface fluid registration method. Vertex-based statistical comparisons between the two groups were performed via four methods: univariate and multivariate tensor-based morphometry, the commonly used medial axis distance, and a combination of the last two statistics. We found statistically significant differences in regional morphology between the two groups that are consistent across statistics, but more extensive for multivariate measures. Differences were localized to the ventral aspect of the striatum. In particular, we found abnormalities in the preterm anterior/inferior putamen, which is interconnected with the medial orbital/prefrontal cortex and the midline thalamic nuclei including the medial dorsal nucleus and pulvinar. These findings support the hypothesis that the ventral striatum is vulnerable, within the cortico-stiato-thalamo-cortical neural circuitry, which may underlie the risk for long-term development of frontal executive dysfunction, attention deficit hyperactivity disorder and attention-related learning disabilities in preterm neonates. © 2013 Shi et al
LE ROMAN ALGÉRIEN DE L'ENTRE-DEUX-GUERRES À L'ÉPREUVE DU POLITIQUE: en lisant Robert Randau et Abdelkader Hadj Hamou
No full textThe political characterization of Algerian literature under the era of colonialism has been widely discussed. Nevertheless, due to its major political dimension - more sensed than debated - scholars have focused primarily on rigid categorization and interpretive templates, at the exclusion of concepts within the texts deviating from the colonial credo. The objective remains to broaden the scope of the Algerian Interwar novel by proposing a reading cognizant of its literary fundamentals (aesthetic, tone, style, rhetoric) and subsequent interaction with ideological agendas, not necessarily in terms of a historical reinterpretation. The ambiguity inherent in the Algerian novel precludes its classification as solely a thesis novel and demands rigor in its perception as multifaceted in nature. Stemming from this, one questions the concept of a thesis novel, presupposing that intrinsic polyphony will conceive not only one, but multiple theses. Without this presupposition, the Algerian Interwar novel becomes a novel of allegiance with disregard to the subtlety and complexity of the colonial environment from which the novel evolved, leading to deprivation of its essence as a literary piece. Indeed, under the colonial regime, the novels were conscripted into the appareil idéologique d'État (Althusser). Despite apparent endorsement of the colonial ideology, the novels themselves generate their own internal mechanisms of subversion, via the creation of an intellectual movement (Algérianisme) which undermines the state-sponsored politico-artistic body. If the novel can be considered at the least as a breaking point of any univocal interpretation (as characters were not created to be the voice of the author), then one must know "that a text is not simply a line of words, yielding a sole meaning in a theological sense (the "message" of the Author/God), but rather exists as a multidimensional space where varied writings join and compete but yet none can be perceived the original source. " (Roland Barthes).The intention of this work is to render justice to these texts by a literary analysis of the writings of Robert Randau and Abdelkader Hadj Hamou. In so doing, various facets and modalities will emerge from the colonial novel which will reject the traditional interpretative readings
High hemocyte load is associated with increased resistance against parasitoids in Drosophila suzukii, a relative of D. melanogaster.
No full textAmong the most common parasites of Drosophila in nature are parasitoid wasps, which lay their eggs in fly larvae and pupae. D. melanogaster larvae can mount a cellular immune response against wasp eggs, but female wasps inject venom along with their eggs to block this immune response. Genetic variation in flies for immune resistance against wasps and genetic variation in wasps for virulence against flies largely determines the outcome of any fly-wasp interaction. Interestingly, up to 90% of the variation in fly resistance against wasp parasitism has been linked to a very simple mechanism: flies with increased constitutive blood cell (hemocyte) production are more resistant. However, this relationship has not been tested for Drosophila hosts outside of the melanogaster subgroup, nor has it been tested across a diversity of parasitoid wasp species and strains. We compared hemocyte levels in two fly species from different subgroups, D. melanogaster and D. suzukii, and found that D. suzukii constitutively produces up to five times more hemocytes than D. melanogaster. Using a panel of 24 parasitoid wasp strains representing fifteen species, four families, and multiple virulence strategies, we found that D. suzukii was significantly more resistant to wasp parasitism than D. melanogaster. Thus, our data suggest that the relationship between hemocyte production and wasp resistance is general. However, at least one sympatric wasp species was a highly successful infector of D. suzukii, suggesting specialists can overcome the general resistance afforded to hosts by excessive hemocyte production. Given that D. suzukii is an emerging agricultural pest, identification of the few parasitoid wasps that successfully infect D. suzukii may have value for biocontrol
Accelerated Growth Plate Mineralization and Foreshortened Proximal Limb Bones in Fetuin-A Knockout Mice
No full textPMCID: PMC3473050This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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Oriental enlightenment: the problematic military experiences and cultural claims of Count Maurice Auguste comte de Benyowsky in Formosa during 1771
No full textMaurice Benyowsky's colourful version of his global adventures during the heady, expansive days of the late-Enlightenment remains still as an historical account, and is perhaps destined for reification at a time of romantic, postmodernist cultural affirmation. Yet this paper argues that within it there lies a virile and possibly dangerous Orientalism, one at least partially based upon a lurid, opportunistic and self-seeking fabrication of his visit to Taiwan (Formosa) in the year 1771. This paper examines the veracity, provenance and historiography of the Benyowsky account of late-eighteenth century Formosa, both as an exercise in one facet of Taiwanese history and as some exploration of the origin and maintenance of European views of the "other" and of the "orient" as they were transforming during the late-Enlightenment period. Furthermore a principal task is to provide an historiographical analysis that illustrates both the initial reasons for the acceptance of Benyowsky's lurid account as well as the wider contexts of its long life as a seemingly reliable and authentic tale. Questions remain as to the cultural contexts of any general acceptance of otherwise doubtful stories, experiments, claims and "adventures". Here there is little doubt that the original Memoirs were given greater credence by Benyowsky's talent in self-fashioning his character and status as those of a reliable gentleman
Fischer decompositions for entire functions of sufficiently low order
No full textThe existence of decompositions of the form f = P ·q+r with P∗ k(D)r =0, where f is entire, P a polynomial and P∗ k the principal part of P with its coefficients conjugated, was achieved in [1] under certain restrictions on the order of f. Here we prove uniqueness, thereby obtaining Fischer decompositions, under conditions that sometimes match those required for existence, and sometimes are more restrictive, depending on the parameters involvedThe first named author was partially supported by Grant PID2019-106870GB-I00 of the MICINN of Spain, by ICMAT Severo Ochoa project CEX2019-000904-S (MICINN), and by V PRICIT (Comunidad de Madrid - Spain
Broad-Spectrum Antiviral Therapeutics
No full textCurrently there are relatively few antiviral therapeutics, and most which do exist are highly pathogen-specific or have other disadvantages. We have developed a new broad-spectrum antiviral approach, dubbed Double-stranded RNA (dsRNA) Activated Caspase Oligomerizer (DRACO) that selectively induces apoptosis in cells containing viral dsRNA, rapidly killing infected cells without harming uninfected cells. We have created DRACOs and shown that they are nontoxic in 11 mammalian cell types and effective against 15 different viruses, including dengue flavivirus, Amapari and Tacaribe arenaviruses, Guama bunyavirus, and H1N1 influenza. We have also demonstrated that DRACOs can rescue mice challenged with H1N1 influenza. DRACOs have the potential to be effective therapeutics or prophylactics for numerous clinical and priority viruses, due to the broad-spectrum sensitivity of the dsRNA detection domain, the potent activity of the apoptosis induction domain, and the novel direct linkage between the two which viruses have never encountered.National Institute of Allergy and Infectious Diseases (U.S.) (grant AI057159)New England Regional Center of Excellence for Biodefense and Emerging Infectious DiseasesUnited States. Dept. of Defense (Director of Defense Research & Engineering)United States. Defense Threat Reduction AgencyUnited States. Defense Advanced Research Projects Agenc
Surfactant protein D inhibits HIV-1 infection of target cells via interference with gp120-CD4 interaction and modulates pro-inflammatory cytokine production
No full text© 2014 Pandit et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Surfactant Protein SP-D, a member of the collectin family, is a pattern recognition protein, secreted by mucosal epithelial cells and has an important role in innate immunity against various pathogens. In this study, we confirm that native human SP-D and a recombinant fragment of human SP-D (rhSP-D) bind to gp120 of HIV-1 and significantly inhibit viral replication in vitro in a calcium and dose-dependent manner. We show, for the first time, that SP-D and rhSP-D act as potent inhibitors of HIV-1 entry in to target cells and block the interaction between CD4 and gp120 in a dose-dependent manner. The rhSP-D-mediated inhibition of viral replication was examined using three clinical isolates of HIV-1 and three target cells: Jurkat T cells, U937 monocytic cells and PBMCs. HIV-1 induced cytokine storm in the three target cells was significantly suppressed by rhSP-D. Phosphorylation of key kinases p38, Erk1/2 and AKT, which contribute to HIV-1 induced immune activation, was significantly reduced in vitro in the presence of rhSP-D. Notably, anti-HIV-1 activity of rhSP-D was retained in the presence of biological fluids such as cervico-vaginal lavage and seminal plasma. Our study illustrates the multi-faceted role of human SPD against HIV-1 and potential of rhSP-D for immunotherapy to inhibit viral entry and immune activation in acute HIV infection. © 2014 Pandit et al.The work (Project no. 2011-16850) was supported by Medical Innovation Fund of Indian Council of Medical Research, New Delhi, India (www.icmr.nic.in/)
Human surfactant protein D alters oxidative stress and HMGA1 expression to induce p53 apoptotic pathway in eosinophil leukemic cell line
No full textThis article is made available through the Brunel Open Access Publishing Fund. Copyright: © 2013 Mahajan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Surfactant protein D (SP-D), an innate immune molecule, has an indispensable role in host defense and regulation of
inflammation. Immune related functions regulated by SP-D include agglutination of pathogens, phagocytosis,
oxidative burst, antigen presentation, T lymphocyte proliferation, cytokine secretion, induction of apoptosis and
clearance of apoptotic cells. The present study unravels a novel ability of SP-D to reduce the viability of leukemic
cells (eosinophilic leukemic cell line, AML14.3D10; acute myeloid leukemia cell line, THP-1; acute lymphoid leukemia
cell lines, Jurkat, Raji; and human breast epithelial cell line, MCF-7), and explains the underlying mechanisms. SP-D
and a recombinant fragment of human SP-D (rhSP-D) induced G2/M phase cell cycle arrest, and dose and timedependent
apoptosis in the AML14.3D10 eosinophilic leukemia cell line. Levels of various apoptotic markers viz.
activated p53, cleaved caspase-9 and PARP, along with G2/M checkpoints (p21 and Tyr15 phosphorylation of cdc2)
showed significant increase in these cells. We further attempted to elucidate the underlying mechanisms of rhSP-D
induced apoptosis using proteomic analysis. This approach identified large scale molecular changes initiated by SPD
in a human cell for the first time. Among others, the proteomics analysis highlighted a decreased expression of
survival related proteins such as HMGA1, overexpression of proteins to protect the cells from oxidative burst, while a
drastic decrease in mitochondrial antioxidant defense system. rhSP-D mediated enhanced oxidative burst in
AML14.3D10 cells was confirmed, while antioxidant, N-acetyl-L-cysteine, abrogated the rhSP-D induced apoptosis.
The rhSP-D mediated reduced viability was specific to the cancer cell lines and viability of human PBMCs from
healthy controls was not affected. The study suggests involvement of SP-D in host’s immunosurveillance and
therapeutic potential of rhSP-D in the eosinophilic leukemia and cancers of other origins.Department of Biotechnology, Indi
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