Chlorogenic acid induces apoptosis to inhibit inflammatory proliferation of IL-6-induced fibroblast-like synoviocytes through modulating the activation of JAK/STAT and NF-κB signaling pathways

PubMed Central

LOU, LIXIA; ZHOU, JINGWEI; LIU, YUJUN; WEI, YI; ZHAO, JIULI; DENG, JIAGANG; DONG, BIN; ZHU, LINGQUN; WU, AIMING; YANG, YINGXI; CHAI, LIMIN

2016-01-01

Chlorogenic acid (CGA) is the primary constituent of Caulis Lonicerae, a Chinese herb used for the treatment of rheumatoid arthritis (RA). The present study aimed to investigate whether CGA was able to inhibit the proliferation of the fibroblast-like synoviocyte cell line (RSC-364), stimulated by interleukin (IL)-6, through inducing apoptosis. Following incubation with IL-6 or IL-6 and CGA, the cellular proliferation of RSC-364 cells was detected by MTT assay. The ratio of apoptosed cells were detected by flow cytometry. Western blot analysis was performed to observe protein expression levels of key molecules involved in the Janus-activated kinase/signal transducer and activator of transcription 3 (JAK/STAT) signaling pathway [phosphorylated (p)-STAT3, JAK1 and gp130] and the nuclear factor κB (NF-κB) signaling pathway [phosphorylated (p)-inhibitor of κB kinase subunit α/β and NF-κB p50). It was revealed that CGA was able to inhibit the inflammatory proliferation of RSC-364 cells mediated by IL-6 through inducing apoptosis. CGA was also able to suppress the expression levels of key molecules in the JAK/STAT and NF-κB signaling pathways, and inhibit the activation of these signaling pathways in the inflammatory response through IL-6-mediated signaling, thereby resulting in the inhibition of the inflammatory proliferation of synoviocytes. The present results indicated that CGA may have potential as a novel therapeutic agent for inhibiting inflammatory hyperplasia of the synovium through inducing synoviocyte apoptosis in patients with RA. PMID:27168850

Intra-articular administration of xenogeneic neonatal Mesenchymal Stromal Cells early after meniscal injury down-regulates metalloproteinase gene expression in synovium and prevents cartilage degradation in a rabbit model of osteoarthritis.

PubMed

Saulnier, N; Viguier, E; Perrier-Groult, E; Chenu, C; Pillet, E; Roger, T; Maddens, S; Boulocher, C

2015-01-01

The anti-inflammatory and anti-catabolic effects of neonatal Mesenchymal Stromal Cell (MSC) were investigated in a xenogeneic model of mild osteoarthritis (OA). The paracrine properties of MSC on synoviocytes were further investigated in vitro. OA was induced by medial meniscal release (MMR) in 30 rabbit knees. A single early (day 3) or delayed (day 15) intra-articular (IA) injection of MSC isolated from equine Umbilical Cord Wharton's jelly (UC-MSC) was performed. Rabbits were euthanized on days 15 or 56. OA grading was performed and gene expression of inflammatory cytokines and metalloproteinases was measured in synovial tissue. Paracrine effects of UC-MSC were investigated using UC-conditioned vs control medium on rabbit primary synoviocytes stimulated with interleukin 1 beta in vitro. No adverse local or systemic responses were observed clinically after xenogeneic UC-MSC injection. At study end point, cartilage fibrillation was lower in early treatment than in delayed treatment group. Cellular infiltrate was observed in the synovium of both UC-MSC groups. OA synovium exhibited a reduced expression of metalloproteinases-1, -3, -13 in the early cell-treated group at d56. In vitro, UC-conditioned medium exerted anti-inflammatory and anti-catabolic effects on synoviocytes exposed to pro-inflammatory stimulus. Early IA injection of equine UC-MSC was effective in preventing OA signs in rabbit knees following MMR. UC-MSC target the synovium and modulate the gene expression pattern of synoviocytes to promote an anti-catabolic environment. This confirms the synovium is a major target and mediator of MSC therapy, modulating the expression of matrix-degrading enzymes. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Spontaneous establishment of an Epstein-Barr virus-infected fibroblast line from the synovial tissue of a rheumatoid arthritis patient.

PubMed Central

Koide, J; Takada, K; Sugiura, M; Sekine, H; Ito, T; Saito, K; Mori, S; Takeuchi, T; Uchida, S; Abe, T

1997-01-01

An Epstein-Barr virus (EBV)-infected fibroblast line, designated DSEK, was spontaneously established from synovial tissue of a patient with rheumatoid arthritis (RA). DSEK cells expressed EBV nuclear antigens EBNA-1 and EBNA-2 and latent membrane protein LMP-1. Cell surface markers of DSEK cells were similar to those of EBV-negative fibroblast clones derived from synoviocytes and were negative for lymphocyte and macrophage markers. DSEK cells expressed CD44, CD58, and HLA-DR antigens and spontaneously produced interleukin-10 basic fibroblast growth factor and transforming growth factor beta1. These results indicate that rheumatoid synoviocytes can be a target for EBV infection and suggest that EBV may play a role in the pathogenesis of RA. PMID:9032386

Hydrogen sulphide decreases IL-1β-induced activation of fibroblast-like synoviocytes from patients with osteoarthritis

PubMed Central

Sieghart, Daniela; Liszt, Melissa; Wanivenhaus, Axel; Bröll, Hans; Kiener, Hans; Klösch, Burkhard; Steiner, Günter

2015-01-01

Balneotherapy employing sulphurous thermal water is still applied to patients suffering from diseases of musculoskeletal system like osteoarthritis (OA) but evidence for its clinical effectiveness is scarce. Since the gasotransmitter hydrogen sulphide (H2S) seems to affect cells involved in degenerative joint diseases, it was the objective of this study to investigate the effects of exogenous H2S on fibroblast-like synoviocytes (FLS), which are key players in OA pathogenesis being capable of producing pro-inflammatory cytokines and matrix degrading enzymes. To address this issue primary FLS derived from OA patients were stimulated with IL-1β and treated with the H2S donor NaHS. Cellular responses were analysed by ELISA, quantitative real-time PCR, phospho-MAPkinase array and Western blotting. Treatment-induced effects on cellular structure and synovial architecture were investigated in three-dimensional extracellular matrix micromasses. NaHS treatment reduced both spontaneous and IL-1β-induced secretion of IL-6, IL-8 and RANTES in different experimental settings. In addition, NaHS treatment reduced the expression of matrix metallo-proteinases MMP-2 and MMP-14. IL-1β induced the phosphorylation of several MAPkinases. NaHS treatment partially reduced IL-1β-induced activation of several MAPK whereas it increased phosphorylation of pro-survival factor Akt1/2. When cultured in spherical micromasses, FLS intentionally established a synovial lining layer-like structure; stimulation with IL-1β altered the architecture of micromasses leading to hyperplasia of the lining layer which was completely inhibited by concomitant exposure to NaHS. These data suggest that H2S partially antagonizes IL-1β stimulation via selective manipulation of the MAPkinase and the PI3K/Akt pathways which may encourage development of novel drugs for treatment of OA. PMID:25312962

Gastrin-releasing peptide and its receptor increase arthritis fibroblast-like synoviocytes invasiveness through activating the PI3K/AKT pathway.

PubMed

Clarimundo, Vanessa Schuck; Farinon, Mirian; Pedó, Renata Ternus; Teixeira, Vivian Oliveira Nunes; Nör, Carolina; Gulko, Percio S; Xavier, Ricardo Machado; de Oliveira, Patricia Gnieslaw

2017-09-01

Rheumatoid arthritis (RA) is an autoimmune disease that leads to joint destruction. The fibroblast-like synoviocytes (FLS) has a central role on the disease pathophysiology. The present study aimed to examine the role of gastrin-releasing peptide (GRP) and its receptor (GRPR) on invasive behavior of mice fibroblast-like synoviocytes (FLS), as well as to evaluate GRP-induced signaling on PI3K/AKT pathway. The expression of GRPR in FLS was investigated by immunocytochemistry, western blot (WB) and qRT-PCR. The proliferation and invasion were assessed by SRB and matrigel-transwell assay after treatment with GRP and/or RC-3095 (GRPR antagonist), and/or Ly294002 (inhibitor of PI3K/AKT pathway). Finally, AKT phosphorylation was assessed by WB. GRPR protein was detected in FLS and the exposure to GRP increased FLS invasion by nearly two-fold, compared with untreated cells (p<0.05), while RC-3095 reversed that effect (p<0.001). GRP also increased phosphorylated AKT expression in FLS. When Ly294002 was added with GRP, it prevented the GRP-induced increased cell invasiveness (p<0.001). These data suggest that GRPR expression in FLS and that exogenous GRP are able to activate FLS invasion. This effect occurs at least in part through the AKT activation. Therefore, understanding of the GRP/GRPR pathway could be relevant in the development of FLS-targeted therapy for RA. Copyright © 2017 Elsevier Inc. All rights reserved.

Mitomycin C induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes via a mitochondrial-mediated pathway.

PubMed

Yan, Chuqi; Kong, Dechao; Ge, Dong; Zhang, Yanming; Zhang, Xishan; Su, Changhui; Cao, Xiaojian

2015-01-01

Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease characterised by prominent synoviocyte hyperplasia and a potential imbalance between the growth and death of fibroblast-like synoviocytes (FLS). Mitomycin C (MMC) has previously been demonstrated to inhibit fibroblast proliferation and to induce fibroblast apoptosis. However, the effects of MMC on the proliferation and apoptosis of human RA FLS and the potential mechanisms underlying its effects remain unknown. Cell viability was determined using the Cell Counting Kit-8 assay. Apoptotic cell death was analysed via Annexin V-FITC/PI double staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling. The production of intracellular reactive oxygen species (ROS) was assessed via flow cytometry, and the changes in mitochondrial membrane potential (ΔΨm) were visualized based on JC-1 staining via fluorescence microscopy. The expression of apoptosis-related proteins was determined via Western blot. Treatment with MMC significantly reduced cell viability and induced apoptosis in RA FLS. Furthermore, MMC exposure was found to stimulate the production of ROS and to disrupt the ΔΨm compared to the control treatment. Moreover, MMC increased the release of mitochondrial cytochrome c, the ratio of Bax/Bcl-2, the activation of caspase-9 and caspase-3, and the subsequent cleavage of poly(ADP-ribose) polymerase. Our findings suggest that MMC inhibits cell proliferation and induces apoptosis in RA FLS, and the mechanism underlying this MMC-induced apoptosis may involve a mitochondrial signalling pathway. © 2015 S. Karger AG, Basel.

Inhibition of TNF-{alpha}-mediated inflammatory responses by a benzodioxolylacetylamino-linked benzothiazole analog in human fibroblast-like synoviocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Young-Rae; Jin, Guo Hua; Lee, Sang-Myeong

Highlights: {yields} We synthesized SPA0537, a benzothiazole analog. {yields} SPA0537 is a potent NF-{kappa}B inhibitor. {yields} SPA0537 suppresses the production of proinflammatory mediators in human rheumatoid fibroblast-like synoviocytes. {yields} SPA0537 is effective at suppressing osteoclast differentiation. -- Abstract: The pathologic processes of rheumatoid arthritis are mediated by a number of cytokines, chemokines, and matrix metalloproteinases, the expressions of which are controlled by NF-{kappa}B. This study was performed to explore the effects of a benzothiazole analog, SPA0537, on the control of the NF-{kappa}B activation pathway. We also investigated whether SPA0537 had any anti-inflammatory effects in human rheumatoid fibroblast-like synoviocytes (FLS). SPA0537more » inhibited the nuclear translocation and the DNA binding of NF-{kappa}B subunits, which correlated with the inhibitory effects on IKK phosphorylation and I{kappa}B{alpha} degradation in TNF-{alpha}-stimulated rheumatoid FLS. These events further suppressed chemokine production, matrix metalloproteinase secretion, and TNF-{alpha}-induced cell proliferation. In addition, SPA0537 inhibited the osteoclast differentiation induced by macrophage colony-stimulating factor (MCSF) and receptor activator of the NF-{kappa}B ligand (RANKL) in bone marrow macrophages. These findings suggest that SPA0537 exerts anti-inflammatory effects in rheumatoid FLS through the inhibition of the NF-{kappa}B pathway. Therefore, it may have therapeutic value for the treatment of rheumatoid arthritis.« less

Identification of CD4+ T-cell-derived CD161+ CD39+ and CD39+CD73+ microparticles as new biomarkers for rheumatoid arthritis.

PubMed

Fan, Wenqiang; Wang, Wenxiang; Wu, Jie; Ma, Ling; Guo, Jinyan

2017-02-01

This study aimed to identify CD4 + T-cell-derived microparticles (MPs) and investigate their roles in rheumatoid arthritis (RA). Synovial fluids from 34 RA, 33 osteoarthritis patients and 42 healthy individuals were analyzed by flow cytometry. Human fibroblast-like synoviocytes and peripheral blood mononuclear cells were cultured with or without isolated MPs, chemokines and cytokines were measured by ELISA. CD4 + CD161 + CD39 + and CD4 + CD39 + CD73 + MPs were abundantly present in RA patients, which were positively or negatively correlated with RA features, respectively. Chemokines CCL20, CCL17 and CCL22, and cytokines IL-17 and IL-10 were influenced by these MPs in human fibroblast-like synoviocytes (HFLS) or PMBCs. CD4 + T-cell-derived CD161 + CD39 + and CD39 + CD73 + MPs could serve as new reciprocal biomarkers for RA evaluation.

Chondrocytes, synoviocytes and dermal fibroblasts all express PH-20, a hyaluronidase active at neutral pH

PubMed Central

El Hajjaji, Hafida; Cole, Ada Asbury; Manicourt, Daniel-Henri

2005-01-01

Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found in chondrocytes, synoviocytes, and dermal fibroblasts, and its levels were enhanced upon stimulation with IL-1. In cell layers extracted with Triton X-100 – but not with octylglucoside – and in culture media, a polyclonal antipeptide anti-PH-20 antibody identified protein bands with a molecular weight similar to that of sperm PH-20 (60 to 65 kDa) and exhibiting a hyaluronidase activity at neutral pH. Further, upon stimulation with IL-1, the amounts of the neutral-active hyaluronidase increased in both cell layers and culture media. These findings contribute potential important new insights into the biology of connective tissues. It is likely that PH-20 facilitates cell-receptor-mediated uptake of HA, while overexpression or uncontrolled expression of the enzyme can cause great havoc to connective tissues: not only does HA fragmentation compromise the structural integrity of tissues, but also the HA fragments generated are highly angiogenic and are potent inducers of proinflammatory cytokines. On the other hand, the enzyme activity may account for the progressive depletion of HA seen in osteoarthritis cartilage, a depletion that is believed to play an important role in the apparent irreversibility of this disease process. PMID:15987477

Effect of two different preparations of platelet-rich plasma on synoviocytes.

PubMed

Assirelli, Elisa; Filardo, Giuseppe; Mariani, Erminia; Kon, Elizaveta; Roffi, Alice; Vaccaro, Franca; Marcacci, Maurilio; Facchini, Andrea; Pulsatelli, Lia

2015-09-01

To analyse the modifications induced by two different platelet-rich plasma (PRP) preparations on osteoarthritis (OA) synoviocytes, by documenting changes in gene expression of factors involved in joint physiopathology. OA synoviocytes were cultured for 7 days in medium with different concentrations of either P-PRP (a pure platelet concentrate without leucocytes but with a limited number of platelets), L-PRP (a higher platelet concentrate containing leucocytes) or platelet-poor plasma (PPP). Gene expression of interleukin (IL)-1beta, IL-6, IL-8/CXCL8, tumour necrosis factor alpha, IL-10, IL-4, IL-13, metalloproteinase-13, tissue inhibitor of metalloproteinase (TIMP)-1, (TIMP)-3, (TIMP)-4, vascular endothelial growth factor, transforming growth factor beta1, fibroblast growth factor (FGF)-2, hepatocyte growth factor (HGF), hyaluronic acid (HA) synthases (HAS)-1, (HAS)-2, and (HAS)-3 was analysed by RT-PCR. HA production was determined in culture supernatants by ELISA. IL-1β, IL-8 and FGF-2 were significantly induced by L-PRP compared to both P-PRP and PPP; HGF was down-modulated by L-PRP versus both P-PRP and PPP, and an inverse dose-response influence was shown for all preparations. Expression level of TIMP-4 was lower in the presence of L-PRP compared with P-PRP. HA production and HAS gene expression did not seem to be modulated by PRP. L-PRP is able to sustain the up-regulation of proinflammatory factors, (IL-1beta, IL-8 and FGF-2), together with a down-modulation of HGF and TIMP-4 expression, two factors that have been recognized as anti-catabolic mediators in cartilage, thus supporting the need to further optimize the PRP preparations to be applied in clinical practice.

Collagen triple helix repeat containing 1 is a new promigratory marker of arthritic pannus.

PubMed

Shekhani, Mohammed Talha; Forde, Toni S; Adilbayeva, Altynai; Ramez, Mohamed; Myngbay, Askhat; Bexeitov, Yergali; Lindner, Volkhard; Adarichev, Vyacheslav A

2016-07-19

The formation of destructive hypercellular pannus is critical to joint damage in rheumatoid arthritis (RA). The collagen triple helix repeat containing 1 (CTHRC1) protein expressed by activated stromal cells of diverse origin has previously been implicated in tissue remodeling and carcinogenesis. We recently discovered that the synovial Cthrc1 mRNA directly correlates with arthritis severity in mice. This study characterizes the role of CTHRC1 in arthritic pannus formation. Synovial joints of mice with collagen antibody-induced arthritis (CAIA) and human RA-fibroblast-like synoviocytes (FLS) were immunostained for CTHRC1, FLS and macrophage-specific markers. CTHRC1 levels in plasma from patients with RA were measured using sandwich ELISA. The migratory response of fibroblasts was studied with a transwell migration assay and time-lapse microscopy. Velocity and directness of cell migration was analyzed by recording the trajectories of cells treated with rhCTHRC1. Immunohistochemical analysis of normal and inflamed synovium revealed highly inducible expression of CTHRC1 in arthritis (10.9-fold). At the tissue level, CTHRC1-expressing cells occupied the same niche as large fibroblast-like cells positive for α-smooth muscle actin (α-SMA) and cadherin 11 (CDH11). CTHRC1 was produced by activated FLS predominantly located at the synovial intimal lining and at the bone-pannus interface. Cultured RA-FLS expressed CDH11, α-SMA, and CTHRC1. Upon treatment with exogenous rhCTHRC1, embryonic fibroblasts and RA-FLS significantly increased migration velocity, directness, and cell length along the front-tail axis (1.4-fold, p < 0.01). CTHRC1 was established as a novel marker of activated synoviocytes in murine experimental arthritis and RA. The pro-migratory effect of CTHRC1 on synoviocytes is considered one of the mechanisms promoting hypercellularity of the arthritic pannus.

HIF-2α-induced chemokines stimulate motility of fibroblast-like synoviocytes and chondrocytes into the cartilage-pannus interface in experimental rheumatoid arthritis mouse models.

PubMed

Huh, Yun Hyun; Lee, Gyuseok; Lee, Keun-Bae; Koh, Jeong-Tae; Chun, Jang-Soo; Ryu, Je-Hwang

2015-10-29

Pannus formation and resulting cartilage destruction during rheumatoid arthritis (RA) depends on the migration of synoviocytes to cartilage tissue. Here, we focused on the role of hypoxia-inducible factor (HIF)-2α-induced chemokines by chondrocytes in the regulation of fibroblast-like synoviocyte (FLS) migration into the cartilage-pannus interface and cartilage erosion. Collagen-induced arthritis (CIA), K/BxN serum transfer, and tumor necrosis factor-α transgenic mice were used as experimental RA models. Expression patterns of HIF-2α and chemokines were determined via immunostaining, Western blotting and RT-PCR. FLS motility was evaluated using transwell migration and invasion assays. The specific role of HIF-2α was determined via local deletion of HIF-2α in joint tissues or using conditional knockout (KO) mice. Cartilage destruction, synovitis and pannus formation were assessed via histological analysis. HIF-2α and various chemokines were markedly upregulated in degenerating cartilage and pannus of RA joints. HIF-2α induced chemokine expression by chondrocytes in both primary culture and cartilage tissue. HIF-2α -induced chemokines by chondrocytes regulated the migration and invasion of FLS. Local deletion of HIF-2α in joint tissues inhibited pannus formation adjacent to cartilage tissue and cartilage destruction caused by K/BxN serum transfer. Furthermore, conditional knockout of HIF-2α in cartilage blocked pannus formation in adjacent cartilage but not bone tissue, along with inhibition of cartilage erosion caused by K/BxN serum transfer. Our findings suggest that chemokines induced by IL-1β or HIF-2α in chondrocytes regulate pannus expansion by stimulating FLS migration and invasion, leading to cartilage erosion during RA pathogenesis.

Identification of key regulators for the migration and invasion of rheumatoid synoviocytes through a systems approach

PubMed Central

You, Sungyong; Yoo, Seung-Ah; Choi, Susanna; Kim, Ji-Young; Park, Su-Jung; Ji, Jong Dae; Kim, Tae-Hwan; Kim, Ki-Jo; Cho, Chul-Soo; Hwang, Daehee; Kim, Wan-Uk

2014-01-01

Rheumatoid synoviocytes, which consist of fibroblast-like synoviocytes (FLSs) and synovial macrophages (SMs), are crucial for the progression of rheumatoid arthritis (RA). Particularly, FLSs of RA patients (RA-FLSs) exhibit invasive characteristics reminiscent of cancer cells, destroying cartilage and bone. RA-FLSs and SMs originate differently from mesenchymal and myeloid cells, respectively, but share many pathologic functions. However, the molecular signatures and biological networks representing the distinct and shared features of the two cell types are unknown. We performed global transcriptome profiling of FLSs and SMs obtained from RA and osteoarthritis patients. By comparing the transcriptomes, we identified distinct molecular signatures and cellular processes defining invasiveness of RA-FLSs and proinflammatory properties of RA-SMs, respectively. Interestingly, under the interleukin-1β (IL-1β)–stimulated condition, the RA-FLSs newly acquired proinflammatory signature dominant in RA-SMs without losing invasive properties. We next reconstructed a network model that delineates the shared, RA-FLS–dominant (invasive), and RA-SM–dominant (inflammatory) processes. From the network model, we selected 13 genes, including periostin, osteoblast-specific factor (POSTN) and twist basic helix–loop–helix transcription factor 1 (TWIST1), as key regulator candidates responsible for FLS invasiveness. Of note, POSTN and TWIST1 expressions were elevated in independent RA-FLSs and further instigated by IL-1β. Functional assays demonstrated the requirement of POSTN and TWIST1 for migration and invasion of RA-FLSs stimulated with IL-1β. Together, our systems approach to rheumatoid synovitis provides a basis for identifying key regulators responsible for pathological features of RA-FLSs and -SMs, demonstrating how a certain type of cells acquires functional redundancy under chronic inflammatory conditions. PMID:24374632

Effects of linear polarized infrared light irradiation on the transcriptional regulation of IL-8 expression in IL-1beta-stimulated human rheumatoid synoviocytes involves phosphorylation of the NF-kappaB RelA subunit.

PubMed

Shibata, Yasuko; Araki, Hidefumi; Oshitani, Toshiyuki; Imaoka, Asayo; Matsui, Masaru; Miyazawa, Keiji; Abiko, Yoshimitsu

2009-03-03

Although recent clinical studies have shown that laser therapy acts as an anti-inflammatory effector in the treatment of some diseases, little is known about the mechanism by which it acts in rheumatoid arthritis (RA) patients. The purpose of our work was to examine how irradiation with linear polarized infrared light (LPIL) suppresses inflammatory responses in the MH7A rheumatoid fibroblast-like synoviocyte cell line. We initially confirmed the effects of two disease-modifying anti-rheumatic treatments, LPIL irradiation and dexamethasone (Dex) administration, under experimental inflammatory conditions using gene chip technology. We found that LPIL exerted a smaller effect on gene transcription than Dex; however, IL-1beta-inducible target genes such as the CXCL type chemokines IL-8, IL-1beta and IL-6 were all clearly suppressed by LPIL to the same degree as by Dex. We also found that IL-1beta-induced release of IL-8 from MH7A cells was completely blocked by pretreatment with the (IL-8) inhibitor Bay11-7085, indicating that activation of NF-kappaB signaling plays an important role in the secretion of IL-8. Although the levels of NFKB1 and RELA transcription were unaffected by IL-1beta stimulation, phosphorylation of RelA S276 was suppressed by both LPIL and Dex. Thus LPIL likely exerts its anti-inflammatory effects by inhibiting the release of the inflammatory chemokine IL-8. A fuller understanding of the anti-inflammatory mechanism of LPIL in rheumatoid synoviocytes could serve as the basis for improved treatment of RA patients in the future.

Brucella and Osteoarticular Cell Activation: Partners in Crime

PubMed Central

Giambartolomei, Guillermo H.; Arriola Benitez, Paula C.; Delpino, M. Victoria

2017-01-01

Osteoarticular brucellosis is the most common presentation of human active disease although its prevalence varies widely. The three most common forms of osteoarticular involvement are sacroiliitis, spondylitis, and peripheral arthritis. The molecular mechanisms implicated in bone damage have been recently elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and the receptor activator of nuclear factor kappa-B ligand (RANKL)-the natural modulator of bone homeostasis are involved. These processes are driven by inflammatory cells, like monocytes/macrophages, neutrophils, Th17 CD4+ T, and B cells. In addition, Brucella abortus has a direct effect on osteoarticular cells and tilts homeostatic bone remodeling. These bacteria inhibit bone matrix deposition by osteoblasts (the only bone cells involved in bone deposition), and modify the phenotype of these cells to produce matrix metalloproteinases (MMPs) and cytokine secretion, contributing to bone matrix degradation. B. abortus also affects osteoclasts (cells naturally involved in bone resorption) by inducing an increase in osteoclastogenesis and osteoclast activation; thus, increasing mineral and organic bone matrix resorption, contributing to bone damage. Given that the pathology induced by Brucella species involved joint tissue, experiments conducted on synoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits synoviocyte apoptosis. Brucella is an intracellular bacterium that replicates preferentially in the endoplasmic reticulum of macrophages. The analysis of B. abortus-infected synoviocytes indicated that bacteria also replicate in their reticulum suggesting that they could use this cell type for intracellular replication during the osteoarticular localization of the disease. Finally, the molecular mechanisms of osteoarticular brucellosis discovered recently shed light on how the interaction between B. abortus and immune and osteoarticular cells may play an important role in producing damage in joint and bone. PMID:28265268

Baicalin Inhibits IL-17-Mediated Joint Inflammation in Murine Adjuvant-Induced Arthritis

PubMed Central

Yang, Xue; Yang, Ji; Zou, Hejian

2013-01-01

T-helper-17 (Th17) cells are implicated in a number of inflammatory disorders including rheumatoid arthritis. Antagonism of Th17 cells is a treatment option for arthritis. Here, we report that Baicalin, a compound isolated from the Chinese herb Huangqin (Scutellaria baicalensis Georgi), relieved ankle swelling and protected the joint against inflammatory destruction in a murine adjuvant-induced arthritis model. Baicalin inhibited splenic Th17 cell population expansion in vivo. Baicalin prevented interleukin- (IL-) 17-mediated lymphocyte adhesion to cultured synoviocytes. Baicalin also blocked IL-17-induced intercellular adhesion molecule 1, vascular cell adhesion molecule 1, IL-6, and tumor necrosis factor-alpha mRNA expression in cultured synoviocytes. Collectively, these findings suggest that Baicalin downregulates the joint inflammation caused by IL-17, which is likely produced by an expanded population of splenic Th17 cells in experimental arthritis. Baicalin might be a promising novel therapeutic agent for treating rheumatoid arthritis in humans. PMID:23840239

CXCR6-CXCL16 interaction in the pathogenesis of Juvenile Idiopathic Arthritis.

PubMed

Martini, Giorgia; Cabrelle, Anna; Calabrese, Fiorella; Carraro, Samuela; Scquizzato, Elisa; Teramo, Antonella; Facco, Monica; Zulian, Francesco; Agostini, Carlo

2008-11-01

In order to evaluate the role of CXCR6/CXCL16 in driving lymphocyte migration into inflamed joints of children with oligoarticular Juvenile Idiopathic Arthritis (JIA) we analysed CXCR6 expression and functional capability in lymphocytes from synovial fluid (SF) by flow cytometry, by real-time polymerase chain reaction (RT-PCR) and migration assays. Furthermore, CXCR6 and CXCL16 expression in synovial tissue (ST) was analysed by immunohistochemistry. T cells isolated from SF of patients with JIA expressed CXCR6 which was functionally active as shown by chemotactic assays. The same cells expressed CXCR3 and it exerted a migratory activity in response to CXCL10. CXCL16 and CXCR6 were intensively expressed on the synovium cells, respectively on macrophages, synoviocytes and endothelial cells and on lymphocytes, synoviocytes and endothelial cells. Taken together, these data suggest that CXCR6 and CXCR3 act coordinately with respective ligands and are involved in the pathophysiology of JIA-associated inflammatory processes.

Cyclic GMP-AMP Synthase Is Required for Cell Proliferation and Inflammatory Responses in Rheumatoid Arthritis Synoviocytes.

PubMed

Wang, Yan; Su, Guo-Hua; Zhang, Fang; Chu, Jing-Xue; Wang, Yun-Shan

2015-01-01

Rheumatoid arthritis (RA) is characterized by inflammatory cell infiltration, fibroblast-like synoviocytes (FLS) invasive proliferation, and joint destruction. Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that induces immune activation. In this study, we examined whether cGAS plays a role in RA FLS. In this study, cGAS was overexpressed in RA-FLS compared with OA FLS. TNFα stimulation induced cGAS expression in RA FLS. Overexpression of cGAS promoted the proliferation and knockdown of cGAS inhibited the proliferation of RA FLS. cGAS overexpression enhanced the production of proinflammatory cytokines and matrix metalloproteinases (MMPs) as well as AKT and ERK phosphorylation in TNFα-stimulated FLS. In contrast, cGAS silencing inhibited production of proinflammatory cytokines and matrix metalloproteinases (MMPs) as well as AKT and ERK phosphorylation in TNFα-stimulated FLS. These results suggest that cGAS activates the AKT and ERK pathways to promote the inflammatory response of RA FLS, and the development of strategies targeting cGAS may have therapeutic potential for human RA.

Tissue factor expression in rheumatoid synovium: a potential role in pannus invasion of rheumatoid arthritis.

PubMed

Chen, Lujun; Lu, Yahua; Chu, Yang; Xie, Jun; Ding, Wen'ge; Wang, Fengming

2013-09-01

Angiogenesis, as well as pannus formation within the joint, plays an important role in the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). Tissue factor (TF), an essential initiator of the extrinsic pathway of blood coagulation, is also involved in the angiogenesis and the pannus formation of RA progression. In the present study, we used immunofluorescence and confocal scanning methods to characterize TF immunolocalization in RA synovium. We showed that positive staining of TF could be immunolocalized in synoviocytes, CD19(+) B cells and CD68(+) macrophages, whereas weak or negative staining of tissue factor could be found in CD34(+) endothelial cells of neo-vessels, CD3(+) T cells and CD14(+) monocytes in RA synovium tissues. Our study demonstrates a detailed local expression of TF in the rheumatoid synovium, and supports the notion that TF, expressed not only by the synoviocytes themselves, but also the infiltrating CD19(+) B cells and CD68(+) macrophages, is involved in the pannus invasion in the progression of rheumatoid arthritis. Copyright © 2013 Elsevier GmbH. All rights reserved.

Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

NASA Astrophysics Data System (ADS)

Kamau Chapman, Sarah W.; Hassa, Paul O.; Koch-Schneidemann, Sabine; von Rechenberg, Brigitte; Hofmann-Amtenbrink, Margarethe; Steitz, Benedikt; Petri-Fink, Alke; Hofmann, Heinrich; Hottiger, Michael O.

Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocytes, chondrocytes, osteoblasts, melanocytes, macrophages, lung fibroblasts, and embryonic fibroblasts. These cells differed in several properties, and hence were a good representative sample of cells that would be targeted for expression and delivery of therapeutic genes in vivo. The efficiency of gene delivery in all these cells was enhanced using polyethylenimine-coated polyMAG magnetic nanoparticles, and the rates (17-84.2%) surpassed those previously achieved using other methods, especially in cells that are difficult to transfect. The application of permanent and pulsating magnetic fields significantly enhanced the transfection efficiencies in synoviocytes, chondrocytes, osteoblasts, melanocytes and lung fibroblasts, within 5 min of exposure to these magnetic fields. This is an added advantage for future in vivo applications, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.

Comprehensive epigenetic landscape of rheumatoid arthritis fibroblast-like synoviocytes.

PubMed

Ai, Rizi; Laragione, Teresina; Hammaker, Deepa; Boyle, David L; Wildberg, Andre; Maeshima, Keisuke; Palescandolo, Emanuele; Krishna, Vinod; Pocalyko, David; Whitaker, John W; Bai, Yuchen; Nagpal, Sunil; Bachman, Kurtis E; Ainsworth, Richard I; Wang, Mengchi; Ding, Bo; Gulko, Percio S; Wang, Wei; Firestein, Gary S

2018-05-15

Epigenetics contributes to the pathogenesis of immune-mediated diseases like rheumatoid arthritis (RA). Here we show the first comprehensive epigenomic characterization of RA fibroblast-like synoviocytes (FLS), including histone modifications (H3K27ac, H3K4me1, H3K4me3, H3K36me3, H3K27me3, and H3K9me3), open chromatin, RNA expression and whole-genome DNA methylation. To address complex multidimensional relationship and reveal epigenetic regulation of RA, we perform integrative analyses using a novel unbiased method to identify genomic regions with similar profiles. Epigenomically similar regions exist in RA cells and are associated with active enhancers and promoters and specific transcription factor binding motifs. Differentially marked genes are enriched for immunological and unexpected pathways, with "Huntington's Disease Signaling" identified as particularly prominent. We validate the relevance of this pathway to RA by showing that Huntingtin-interacting protein-1 regulates FLS invasion into matrix. This work establishes a high-resolution epigenomic landscape of RA and demonstrates the potential for integrative analyses to identify unanticipated therapeutic targets.

Increased autophagy in fibroblast-like synoviocytes leads to immune enhancement potential in rheumatoid arthritis.

PubMed

Yang, Ru; Zhang, Yingzi; Wang, Lin; Hu, Ji; Wen, Jian; Xue, Leixi; Tang, Mei; Liu, Zhichun; Fu, Jinxiang

2017-02-28

The incidence of rheumatoid arthritis (RA) has been reported to be correlated with a disorder of immunregulation. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) play an important role in regulating the local immune microenvironment. However, the potential mechanism of RA-FLS in regulating the immnue response is not clearly understood. In this study, we demonstrated that the expression of HIF-1α was significantly up-regulated in rheumatoid arthritis tissue which indicated that the hypoxia condition in the microenvironment. We also observed that RA-FLSs demonstrated the potential to up-regulate immune activation. Meanwhile, the level of autophagy increased in RA-FLSs compared with control group. Besides that, the expression of IL-6 was up-regulated not only in RA-FLSs but also in the fibroblasts that treated with hypoxia condition. Accordingly, we found that autophagy inhibitiors could effectively inhibit the immune activation function of RA-FLSs medicated by IL-6. Taken together, the results we demonstrated above indicated that the hypoxia microenvironment could effectively induce the incidence of autophagy and then lead to the immune activation function of RA-FLSs medicated by IL-6.

Evaluation of the effect of polyphenol of escin compared with ibuprofen and dexamethasone in synoviocyte model for osteoarthritis: an in vitro study.

PubMed

Maghsoudi, Hossein; Hallajzadeh, Jamal; Rezaeipour, Mozhghan

2018-04-16

Osteoarthritis (OA) is a chronic degenerative joint disease with inflammatory component. It is associated with progressive histological alterations and disabling symptoms. Today, drugs such as glucocorticoids (GCs) and nonsteroidal anti-inflammatory drugs (NSIADs) are commonly employed for treatment of osteoarthritis, but have serious and life-threatening side effects. The aim of the current study is to evaluate the effects of escin on cyclooxygenase-2 (COX-2, isoform), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor-alpha (TNF-α), and nitric oxide (NO) (1), as well as prostaglandin E2 (PGE2) on inflammatory cells, similar osteoarthritis in synoviocytes, and monocytes/macrophages, and to compare it with dexamethasone (DEX) and ibuprofen (IBP). Synovial cells were isolated from synovial membrane of the radiocarpal joint cartilage of an 8-month-old Holstein cow. THP-1 cells were prepared from Pasteur Institute of Iran. Cells were cultivated and exposed to lipopolysaccharide (LPS) stimulation without, or in the presence of, DEX, IBP, or escin. The gene expressions of IL-1β, TNF-α, IL-18, COX-2, and iNOS were evaluated by real-time PCR. Concentrations of NO and PGE2 were measured by ELISA methods. Our cells secreted an increased amounts of IL-1β, TNF-α, IL-18, COX-2, iNOS, NO, and PGE2 in response to LPS stimulation in all conditions. Escin can quench the gene expression of COX-2, iNOS, IL-1β, IL-18, and TNF-α in synoviocyte cells and production of NO and PGE2 in monocyte/macrophage cells alike DEX and IBP. We can use from escin for the treatment of osteoarthritis as an anti-inflammatory agent in the latter but further studies to support the results from such a model are needed.

The tumour-associated glycoprotein podoplanin is expressed in fibroblast-like synoviocytes of the hyperplastic synovial lining layer in rheumatoid arthritis

PubMed Central

2011-01-01

Introduction Activated fibroblast-like synoviocytes (FLSs) in rheumatoid arthritis (RA) share many characteristics with tumour cells and are key mediators of synovial tissue transformation and joint destruction. The glycoprotein podoplanin is upregulated in the invasive front of several human cancers and has been associated with epithelial-mesenchymal transition, increased cell migration and tissue invasion. The aim of this study was to investigate whether podoplanin is expressed in areas of synovial transformation in RA and especially in promigratory RA-FLS. Methods Podoplanin expression in human synovial tissue from 18 RA patients and nine osteoarthritis (OA) patients was assessed by immunohistochemistry and confirmed by Western blot analysis. The expression was related to markers of synoviocytes and myofibroblasts detected by using confocal immunofluoresence microscopy. Expression of podoplanin, with or without the addition of proinflammatory cytokines and growth factors, in primary human FLS was evaluated by using flow cytometry. Results Podoplanin was highly expressed in cadherin-11-positive cells throughout the synovial lining layer in RA. The expression was most pronounced in areas with lining layer hyperplasia and high matrix metalloproteinase 9 expression, where it coincided with upregulation of α-smooth muscle actin (α-sma). The synovium in OA was predominantly podoplanin-negative. Podoplanin was expressed in 50% of cultured primary FLSs, and the expression was increased by interleukin 1β, tumour necrosis factor α and transforming growth factor β receptor 1. Conclusions Here we show that podoplanin is highly expressed in FLSs of the invading synovial tissue in RA. The concomitant upregulation of α-sma and podoplanin in a subpopulation of FLSs indicates a myofibroblast phenotype. Proinflammatory mediators increased the podoplanin expression in cultured RA-FLS. We conclude that podoplanin might be involved in the synovial tissue transformation and increased migratory potential of activated FLSs in RA. PMID:21385358

Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-{kappa}B ligand (RANKL) expression in rheumatoid arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeshita, Harunori; Kitano, Masayasu, E-mail: mkitano6@hyo-med.ac.jp; Iwasaki, Tsuyoshi

Highlights: Black-Right-Pointing-Pointer MH7A cells and CD4{sup +} T cells expressed S1P1 and RANKL. Black-Right-Pointing-Pointer S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells. Black-Right-Pointing-Pointer The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-{kappa}B ligand (RANKL) in RA synoviocytes and CD4{sup +} T cells. We demonstrated MH7Amore » cells, a human RA synovial cell line, and CD4{sup +} T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-{alpha} in MH7A cells and CD4{sup +} T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4{sup +} T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.« less

Imaging of normal and pathologic joint synovium using nonlinear optical microscopy as a potential diagnostic tool

NASA Astrophysics Data System (ADS)

Tiwari, Nivedan; Chabra, Sanjay; Mehdi, Sheherbano; Sweet, Paula; Krasieva, Tatiana B.; Pool, Roy; Andrews, Brian; Peavy, George M.

2010-09-01

An estimated 1.3 million people in the United States suffer from rheumatoid arthritis (RA). RA causes profound changes in the synovial membrane of joints, and without early diagnosis and intervention, progresses to permanent alterations in joint structure and function. The purpose of this study is to determine if nonlinear optical microscopy (NLOM) can utilize the natural intrinsic fluorescence properties of tissue to generate images that would allow visualization of the structural and cellular composition of fresh, unfixed normal and pathologic synovial tissue. NLOM is performed on rabbit knee joint synovial samples using 730- and 800-nm excitation wavelengths. Less than 30 mW of excitation power delivered with a 40×, 0.8-NA water immersion objective is sufficient for the visualization of synovial structures to a maximum depth of 70 μm without tissue damage. NLOM imaging of normal and pathologic synovial tissue reveals the cellular structure, synoviocytes, adipocytes, collagen, vascular structures, and differential characteristics of inflammatory infiltrates without requiring tissue processing or staining. Further study to evaluate the ability of NLOM to assess the characteristics of pathologic synovial tissue and its potential role for the management of disease is warranted.

Hypoxia-induced autophagy is inhibited by PADI4 knockdown, which promotes apoptosis of fibroblast-like synoviocytes in rheumatoid arthritis

PubMed Central

Fan, Tingting; Zhang, Changsong; Zong, Ming; Fan, Lieying

2018-01-01

Impaired apoptosis of rheumatoid arthritis (RA)-fibroblast-like synoviocytes (FLS) is pivotal in the process of RA. Peptidyl arginine deiminase type IV (PADI4) is associated with autoantibody regulation via histone citrullination in RA. The present study aimed to investigate the role of PADI4 in the apoptosis of RA-FLS. FLS were isolated from patients with RA and a rat model. The effects of PADI4 on RA-FLS were investigated in vitro and in vivo. Hypoxia-induced autophagy was induced by 1% O2 and was detected by immunohistochemical and immunofluorescence analysis; in addition, apoptosis was detected by flow cytometry. RA-FLS obtained from RA rat model exhibited significant proliferation under severe hypoxia conditions. Hypoxia also significantly induced autophagy and elevated the expression of PADI4. Subsequently, short hairpin RNA-mediated PADI4 knockdown was demonstrated to significantly inhibit hypoxia-induced autophagy and promote apoptosis in RA-FLS. The results of these in vitro and in vivo studies suggested that PADI4 may be closely associated with hypoxia-induced autophagy, and the inhibition of hypoxia-induced autophagy by PADI4 knockdown may contribute to an increase in the apoptosis of RA-FLS. PMID:29393388

Incidental synovial myxoma with extensive intermuscular infiltration in a dog.

PubMed

Izawa, Takeshi; Tanaka, Miyuu; Aoki, Mika; Ohashi, Fumihito; Yamate, Jyoji; Kuwamura, Mitsuru

2012-12-01

A 16-year-old male mixed-breed dog was euthanized due to progression of renal failure caused by renal adenocarcinoma in the left kidney. Apart from main symptomatic lesion, accumulation of transparent jelly-like fluid was observed between the right femoral muscles. Gross examination of the right hindlimb revealed multiple nodules in the articular surface and capsule of the stifle joints, which extended into the crural muscles. Histopathologically, the joint and intermuscular masses were characterized by variously-sized hypocellular nodules consisting of spindle to stellate cells suspended in an abundant myxoid matrix. There were cystic structures within the intermuscular masses, lined by synoviocyte-like cells. Based on the gross and histopathologic findings, the case was diagnosed as synovial myxoma with extensive intermuscular infiltration. Synovial myxoma should be considered in the differential diagnosis of dogs with myxomatous tumor between skeletal muscles, even in absence of joint or muscle symptoms.

Development of a Novel Segmental Bone Defect Construct

DTIC Science & Technology

2017-10-01

differentiation, and biological activity of both primary synoviocytes and bone marrow derived connective tissue progenitor cells. During the majority of...halted activity on the project from the dates of 31 May 2016 to 13 July 2017. However, the project is on schedule with the current, revised project...supervised all project activities and participated in the preparation of the manuscript that was produced during this reporting period. Name: Dr

Krüppel-like factor 4 regulates the expression of inducible nitric oxide synthase induced by TNF-α in human fibroblast-like synoviocyte MH7A cells.

PubMed

Mo, Xuanrong; Chen, Jie; Wang, Xinjuan; Pan, Zhenyu; Ke, Yuping; Zhou, Zhidong; Xie, Jiangwen; Lv, Guoju; Luo, Xinjing

2018-01-01

Krüppel-like factor 4 (KLF4), a zinc finger transcription factor, has been implicated in the inflammation mediated by macrophages and endothelial cells by regulating the expression of inflammatory mediators. Here, we investigated whether KLF4 affects the expression of inducible nitric oxide synthase (iNOS), an important inflammatory mediator, in the human RA fibroblast-like synovial cell line MH7A. A pcDNA3.1-KLF4 plasmid or short interfering RNA KLF4 was transfected into MH7A cells, and the iNOS expression and nitric oxide (NO) production were analyzed by quantitative PCR, immunoblotting, and nitrite measurement. The iNOS promoter activity was determined by luciferase assay. The results showed overexpression of KLF4 increased iNOS expression and NO production in the presence or absence of TNF-α. Conversely, KLF4 knockdown markedly reduced iNOS expression and NO production induced by TNF-α. KLF4 activated the transcription activity of iNOS promoter in MH7A cells stimulated by TNF-α. This study indicates that KLF4 is important for regulating the expression of iNOS by TNF-α in human synoviocytes.

15-hydroxyprostaglandin dehydrogenase is upregulated by hydroxychloroquine in rheumatoid arthritis fibroblast-like synoviocytes.

PubMed

Kim, Hak-Jae; Lee, Sora; Lee, Haw-Yong; Won, Hansol; Chang, Sung-Hae; Nah, Seong-Su

2015-09-01

15-Hydroxyprostaglandin dehydrogenase (HPGD) is the key enzyme responsible for the metabolic inactivation of prostaglandin E2 (PGE2) catabolism. PGE2 is one of the predominant catabolic factors involved in rheumatoid arthritis (RA). However, the expression and regulation of HPGD in RA fibroblast‑like synoviocyte (FLS) remain to be elucidated. Disease‑modifying anti‑rheumatic drugs (DMARDs) are the most important anti‑arthritic drugs, which reduce the effect of joint injury. The aim of the present study was to assess the expression of HPGD in RA tissues and cells, and normal synovial tissues and cells. The effect of the most popular DMARDs, hydroxychloroquine, on the expression of HPGD in RA‑FLS was also investigated. Western blotting and immunohistochemical analysis demonstrated that the expression levels of HPGD in human synovium were lower in RA synovium compared with the normal and OA synovium. In RA‑FLS, the expression of HPGD was increased following treatment with several DMARDs, including sulfasalazine, methotrexate, and hydroxychloroquine. Hydroxychloroquine (10 µM) treatment induced the phosphorylation of ERK, SAPK/JNK and p38. Hydroxychloroquine induced a decrease in the release of PGE2, which was restored by mitogen‑activated protein (MAP) kinase pathway inhibitors. Hydroxychloroquine may therefore, affect the pathogenesis of RA through the MAP kinase pathway by regulating the expression of HPGD.

15-Hydroxyprostaglandin dehydrogenase is upregulated by hydroxychloroquine in rheumatoid arthritis fibroblast-like synoviocytes

PubMed Central

KIM, HAK-JAE; LEE, SORA; LEE, HAW-YONG; WON, HANSOL; CHANG, SUNG-HAE; NAH, SEONG-SU

2015-01-01

15-Hydroxyprostaglandin dehydrogenase (HPGD) is the key enzyme responsible for the metabolic inactivation of prostaglandin E2 (PGE2) catabolism. PGE2 is one of the predominant catabolic factors involved in rheumatoid arthritis (RA). However, the expression and regulation of HPGD in RA fibroblast-like synoviocyte (FLS) remain to be elucidated. Disease-modifying anti-rheumatic drugs (DMARDs) are the most important anti-arthritic drugs, which reduce the effect of joint injury. The aim of the present study was to assess the expression of HPGD in RA tissues and cells, and normal synovial tissues and cells. The effect of the most popular DMARDs, hydroxychloroquine, on the expression of HPGD in RA-FLS was also investigated. Western blotting and immuno-histochemical analysis demonstrated that the expression levels of HPGD in human synovium were lower in RA synovium compared with the normal and OA synovium. In RA-FLS, the expression of HPGD was increased following treatment with several DMARDs, including sulfasalazine, methotrexate, and hydroxychloroquine. Hydroxychloroquine (10 µM) treatment induced the phosphorylation of ERK, SAPK/JNK and p38. Hydroxychloroquine induced a decrease in the release of PGE2, which was restored by mitogen-activated protein (MAP) kinase pathway inhibitors. Hydroxychloroquine may therefore, affect the pathogenesis of RA through the MAP kinase pathway by regulating the expression of HPGD. PMID:26082314

Hypoxia‑induced autophagy is inhibited by PADI4 knockdown, which promotes apoptosis of fibroblast‑like synoviocytes in rheumatoid arthritis.

PubMed

Fan, Tingting; Zhang, Changsong; Zong, Ming; Fan, Lieying

2018-04-01

Impaired apoptosis of rheumatoid arthritis (RA)‑fibroblast‑like synoviocytes (FLS) is pivotal in the process of RA. Peptidyl arginine deiminase type IV (PADI4) is associated with autoantibody regulation via histone citrullination in RA. The present study aimed to investigate the role of PADI4 in the apoptosis of RA‑FLS. FLS were isolated from patients with RA and a rat model. The effects of PADI4 on RA‑FLS were investigated in vitro and in vivo. Hypoxia‑induced autophagy was induced by 1% O2 and was detected by immunohistochemical and immunofluorescence analysis; in addition, apoptosis was detected by flow cytometry. RA‑FLS obtained from RA rat model exhibited significant proliferation under severe hypoxia conditions. Hypoxia also significantly induced autophagy and elevated the expression of PADI4. Subsequently, short hairpin RNA‑mediated PADI4 knockdown was demonstrated to significantly inhibit hypoxia‑induced autophagy and promote apoptosis in RA‑FLS. The results of these in vitro and in vivo studies suggested that PADI4 may be closely associated with hypoxia‑induced autophagy, and the inhibition of hypoxia‑induced autophagy by PADI4 knockdown may contribute to an increase in the apoptosis of RA‑FLS.

Identification and suppression of epidermal growth factor receptor variant III signaling in fibroblast-like synoviocytes from aggressive rheumatoid arthritis by the mimotope.

PubMed

Niu, Jianying; Li, Changhong; Jin, Yinji; Xing, Rui; Sun, Lin; Yu, Ruohan; Jian, Leilei; Liu, Xiangyuan; Yang, Lin

2018-06-01

Epidermal growth factor receptor (EGFR) signaling has been reported to play a vital role in the pathogenesis of rheumatoid arthritis (RA). In current study, we sought to observe whether the active immunization induced by the mimotope could recognize EGFR, inhibit their signaling and disrupt the pathogenic behavior of fibroblast-like synoviocytes (FLS) from RA patients. We prepared a linked EGFR mimotope and performed series of experiments to detect whether the mimotope could induce the desired immune responses. To our surprises, we detected the expression of EGFR variant III (EGFRvIII), but not EGFR in the synovial tissues and FLS from patients with aggressive RA by the linked EGFR mimotope-induced antibodies (LEMIA). Meanwhile, LEMIA could inhibit the signaling caused by the autophosphorylation of EGFRvIII in the FLS. The proliferation, migration, invasion and anti-apoptosis capabilities of the EGFRvIII-expressed FLS were disrupted by LEMIA. These results suggest that EGFRvIII signaling may participate in the malignant behaviors of FLS from aggressive RA. Meanwhile, the linked EGFR mimotope could be used to detect the expression of EGFRvIII and developed to be a potential therapy agent against the aggressive FLS. Copyright © 2018 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Intraarticular expression of biologically active interleukin 1-receptor-antagonist protein by ex vivo gene transfer.

PubMed Central

Bandara, G; Mueller, G M; Galea-Lauri, J; Tindal, M H; Georgescu, H I; Suchanek, M K; Hung, G L; Glorioso, J C; Robbins, P D; Evans, C H

1993-01-01

Gene therapy offers a radical different approach to the treatment of arthritis. Here we have demonstrated that two marker genes (lacZ and neo) and cDNA coding for a potentially therapeutic protein (human interleukin 1-receptor-antagonist protein; IRAP or IL-1ra) can be delivered, by ex vivo techniques, to the synovial lining of joints; intraarticular expression of IRAP inhibited intraarticular responses to interleukin 1. To achieve this, lapine synoviocytes were first transduced in culture by retroviral infection. The genetically modified synovial cells were then transplanted by intraarticular injection into the knee joints of rabbits, where they efficiently colonized the synovium. Assay of joint lavages confirmed the in vivo expression of biologically active human IRAP. With allografted cells, IRAP expression was lost by 12 days after transfer. In contrast, autografted synoviocytes continued to express IRAP for approximately 5 weeks. Knee joints expressing human IRAP were protected from the leukocytosis that otherwise follows the intraarticular injection of recombinant human interleukin 1 beta. Thus, we report the intraarticular expression and activity of a potentially therapeutic protein by gene-transfer technology; these experiments demonstrate the feasibility of treating arthritis and other joint disorders with gene therapy. Images Fig. 1 Fig. 2 PMID:8248169

Theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains

NASA Astrophysics Data System (ADS)

Zhu, Ning; Sun, Shou-Guang; Li, Qiang; Zou, Hua

2014-12-01

One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating conditions. This study conducts theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains. The quasistatic load series that corresponds to quasi-static deformation modes are identified according to the structural form and bearing conditions of high-speed train bogie frames. Moreover, a force-measuring frame is designed and manufactured based on the quasi-static load series. The load decoupling model of the quasi-static load series is then established via calibration tests. Quasi-static load-time histories, together with online tests and decoupling analysis, are obtained for the intermediate range of the Beijing—Shanghai dedicated passenger line. The damage consistency calibration of the quasi-static discrete load spectra is performed according to a damage consistency criterion and a genetic algorithm. The calibrated damage that corresponds with the quasi-static discrete load spectra satisfies the safety requirements of bogie frames.

An easily implemented static condensation method for structural sensitivity analysis

NASA Technical Reports Server (NTRS)

Gangadharan, S. N.; Haftka, R. T.; Nikolaidis, E.

1990-01-01

A black-box approach to static condensation for sensitivity analysis is presented with illustrative examples of a cube and a car structure. The sensitivity of the structural response with respect to joint stiffness parameter is calculated using the direct method, forward-difference, and central-difference schemes. The efficiency of the various methods for identifying joint stiffness parameters from measured static deflections of these structures is compared. The results indicate that the use of static condensation can reduce computation times significantly and the black-box approach is only slightly less efficient than the standard implementation of static condensation. The ease of implementation of the black-box approach recommends it for use with general-purpose finite element codes that do not have a built-in facility for static condensation.

Interleukin-22 Secreted by NKp44+ Natural Killer Cells Promotes Proliferation of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

PubMed Central

Zhu, Junqing; Jia, Ertao; Zhou, Yi; Xu, Juan; Feng, Zhitao; Wang, Hao; Chen, Xiaoguang; Li, Juan

2015-01-01

Abstract Although CD3-CD56+NKp44+ natural killer (NKp44+NK) cells have been linked to autoimmune diseases including inflammatory bowel disease, ankylosing spondylitis, and primary Sjogren syndrome, the expansion and role of those cells in patients with rheumatoid arthritis (RA) remain less defined. Here, we investigate the proportion and pathogenesis of NKp44+NK cells in patients with RA. The results show NKp44+NK cells significantly expanded in RA peripheral blood and synovial fluid, which were correlated positively with RA disease activity. They also highly expressed in RA synovial tissues and secreted a high concentration of interleukin-22 (IL-22) in vitro. Further, NKp44+NK cells culture supernatant promoted the proliferation of fibroblast-like synoviocytes (FLS) which was blocked by IL-22 antagonist and AG490. Treated with recombination human IL-22, the proliferation and phosphorylation-STAT3 on RA-FLS increased in a dose-dependent manner and time-dependent manner; the progress of which could be blocked by AG490. The present study clarifies the expansion of NKp44+NK cells in the peripheral blood and synovial fluid of patients with RA, especially in the synovial tissues of RA for the first time. STAT3 is an essential pathway in mediating the effects of IL-22 secreted by NKp44+NK cells on the proliferation of FLS in patients with RA. PMID:26717357

Gelatinase activity in synovial fluid and synovium obtained from healthy and osteoarthritic joints of dogs.

PubMed

Volk, Susan W; Kapatkin, Amy S; Haskins, Mark E; Walton, Raquel M; D'Angelo, Marina

2003-10-01

To determine matrix metalloproteinase (MMP) activity in synovial fluid (SF) obtained from the joints of dogs with degenerative joint disease (DJD) secondary to various underlying conditions. 35 samples of SF obtained from 18 clinically normal (control) dogs and 34 samples of SF obtained from 17 dogs with DJD; dogs with DJD were from 2 populations (client-owned dogs and research dogs that had DJD secondary to the lysosomal storage disease mucopolysaccharidosis VII). MMP activity in samples of SF was semiquantitatively examined by use of gelatin or casein zymography. Western blot analysis was performed by use of antibodies for MMP-2 and MMP-9. In addition, in situ MMP activity was observed in sections of synovial membrane obtained from healthy and osteoarthritic joints. Samples of SF from osteoarthritic joints had higher MMP-2 activity and dramatically increased MMP-9 activity, compared with values for healthy joints. Substrate-overlay analyses indicated minimal gelatin-degrading activity in synoviocytes obtained from control dogs, whereas greater activity was seen in osteoarthritic synoviocytes, with additional activity in the underlying tissue. Higher MMP-2 activity and dramatic increases in MMP-9 activity were associated with the osteoarthritic state, even though MMP-2 activity was detected in healthy joints. This study expands information on MMP production in SF of osteoarthritic joints in other species and documents the similarity of MMP activity patterns regardless of the cause of DJD.

Inhibition of IL-1{beta}-mediated inflammatory responses by the I{kappa}B{alpha} super-repressor in human fibroblast-like synoviocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Young-Rae; Kweon, Suc-Hyun; Kwon, Kang-Beom

The IL-1{beta}-NF-{kappa}B axis is a key pathway in the pathogenesis of rheumatoid arthritis (RA) and is central in the production of proinflammatory mediators in the inflamed synovium. Therefore, we examined whether fibroblast-like synoviocytes (FLS) could be spared from IL-1{beta}-induced toxicity by an overexpressing I{kappa}B super-repressor. Infection of FLS with Ad-I{kappa}B{alpha} (S32A, S36A), an adenovirus-containing mutant I{kappa}B{alpha}, inhibited IL-1{beta}-induced nuclear translocation and DNA binding of NF-{kappa}B. In addition, Ad-I{kappa}B{alpha} (S32A, S36A) prevented IL-1{beta}-induced inflammatory responses; namely, the production of chemokines, such as ENA-78 and RANTES, and activation of MMP-1 and MMP-3. Finally, increased cellular proliferation of FLS after IL-1{beta} treatment wasmore » significantly reduced by Ad-I{kappa}B{alpha} (S32A, S36A). However, Ad-I{kappa}B{beta} (S19A, S23A), the I{kappa}B{beta} mutant, was not effective in preventing IL-1{beta} toxicity. These results suggest that inhibition of I{kappa}B{alpha} degradation is a potential target for the prevention of joint destruction in patients with RA.« less

Influence of static habitat attributes on local and regional Rocky intertidal community structure

USGS Publications Warehouse

Konar, B.; Iken, K.; Coletti, H.; Monson, Daniel H.; Weitzman, Ben P.

2016-01-01

Rocky intertidal communities are structured by local environmental drivers, which can be dynamic, fluctuating on various temporal scales, or static and not greatly varying across years. We examined the role of six static drivers (distance to freshwater, tidewater glacial presence, wave exposure, fetch, beach slope, and substrate composition) on intertidal community structure across the northern Gulf of Alaska. We hypothesized that community structure is less similar at the local scale compared with the regional scale, coinciding with static drivers being less similar on smaller than larger scales. We also hypothesized that static attributes mainly drive local biological community structure. For this, we surveyed five to six sites in each of the six regions in the mid and low intertidal strata. Across regions, static attributes were not consistently different and only small clusters of sites had similar attributes. Additionally, intertidal communities were less similar on the site compared with the region level. These results suggest that these biological communities are not strongly influenced by the local static attributes measured in this study. An alternative explanation is that static attributes among our regions are not different enough to influence the biological communities. This lack of evidence for a strong static driver may be a result of our site selection, which targeted rocky sheltered communities. This suggests that this habitat may be ideal to examine the influence of dynamic drivers. We recommend that future analyses of dynamic attributes may best be performed after analyses have demonstrated that sites do not differ in static attributes.

Contagion processes on the static and activity-driven coupling networks

NASA Astrophysics Data System (ADS)

Lei, Yanjun; Jiang, Xin; Guo, Quantong; Ma, Yifang; Li, Meng; Zheng, Zhiming

2016-03-01

The evolution of network structure and the spreading of epidemic are common coexistent dynamical processes. In most cases, network structure is treated as either static or time-varying, supposing the whole network is observed in the same time window. In this paper, we consider the epidemics spreading on a network which has both static and time-varying structures. Meanwhile, the time-varying part and the epidemic spreading are supposed to be of the same time scale. We introduce a static and activity-driven coupling (SADC) network model to characterize the coupling between the static ("strong") structure and the dynamic ("weak") structure. Epidemic thresholds of the SIS and SIR models are studied using the SADC model both analytically and numerically under various coupling strategies, where the strong structure is of homogeneous or heterogeneous degree distribution. Theoretical thresholds obtained from the SADC model can both recover and generalize the classical results in static and time-varying networks. It is demonstrated that a weak structure might make the epidemic threshold low in homogeneous networks but high in heterogeneous cases. Furthermore, we show that the weak structure has a substantive effect on the outbreak of the epidemics. This result might be useful in designing some efficient control strategies for epidemics spreading in networks.

A static induction device manufactured by silicon direct bonding

NASA Astrophysics Data System (ADS)

Chen, Xin'an; Liu, Su; Huang, Qing'an

2004-07-01

It is always a key problem how to improve the gate-source breakdown voltage (VGK) of static induction devices during manufacturing. By using a silicon direct bonding process to replace the high resistivity epitaxy process, a bonding buried gate structure is formed, which is different from an epitaxy buried gate structure. The new structure can improve the gate-source breakdown voltage from the process and the structure. It is shown that the bonding buried gate structure is a promising structure, that can improve the VGK and other performances of devices, by manufacture of a static induction thyristor.

Structural testing for static failure, flutter and other scary things

NASA Technical Reports Server (NTRS)

Ricketts, R. H.

1983-01-01

Ground test and flight test methods are described that may be used to highlight potential structural problems that occur on aircraft. Primary interest is focused on light-weight general aviation airplanes. The structural problems described include static strength failure, aileron reversal, static divergence, and flutter. An example of each of the problems is discussed to illustrate how the data acquired during the tests may be used to predict the occurrence of the structural problem. While some rules of thumb for the prediction of structural problems are given the report is not intended to be used explicitly as a structural analysis handbook.

Validity of SW982 synovial cell line for studying the drugs against rheumatoid arthritis in fluvastatin-induced apoptosis signaling model

PubMed Central

Chang, Jae-Ho; Lee, Kyu-Jae; Kim, Soo-Ki; Yoo, Dae-Hyun; Kang, Tae-Young

2014-01-01

Background & objectives: To study effects of drugs against rheumatoid arthritis (RA) synoviocytes or fibroblast like synoviocytes (FLS) are used. To overcome the drawbacks of using FLS, this study was conducted to show the validity of SW982 synovial cell line in RA study. Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Annexin V propidium iodide (PI) staining, mitochondrial membrane potential assay, Triton X-114 Phase partitioning, and immunolot for apoptosis signaling in SW982 human synovial cell line were performed. Results: Fluvastatin induced apoptosis in a dose- and time-dependent manner in TNFα -stimulated SW982 human synovial cells. A geranylgeranylpyrophosphate (GGPP) inhibitor, but not a farnesylpyrophosphate (FPP) inhibitor, induced apoptosis, and fluvastatin-induced apoptosis was associated with the translocation of isoprenylated RhoA and Rac1 proteins from the cell membrane to the cytosol. Fluvastatin-induced downstream apoptotic signals were associated with inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Accordingly, 89 kDa apoptotic cleavage fragment of poly (ADP-ribose) polymerase (PARP) was detected. Interpretation & conclusions: Collectively, our data indicate that fluvastatin induces apoptotic cell death in TNFα-stimulated SW982 human synovial cells through the inactivation of the geranylgerenylated membrane fraction of RhoA and Rac1 proteins and the subsequent inhibition of the PI3K/Akt signaling pathway. This finding shows the validity of SW982 cell line for RA study. PMID:24604047

Proteins related to the functions of fibroblast-like synoviocytes identified by proteomic analysis.

PubMed

Zhang, Hui; Fan, Lie Ying; Zong, Ming; Sun, Li Shan; Lu, Liu

2012-01-01

It is well known that the fibroblast-like synoviocytes (FLS) play a key role in pathogenesis of rheumatoid arthritis (RA). This study was performed to separate the differentially expressed proteins of FLS from the patients with RA or osteoarthritis (OA) by two-dimensional electrophoresis (2-DE), and found proteins associated with the functions of FLS by mass spectrometry (MS). Total proteins were extracted and quantified from the primary cultured FLS from patients of RA (n=8) or OA (n=6). Proteins were separated by high-resolution 2-DE, and identified the differentially expressed proteins by MS. Western blot analyses was used to validated the expression of candidate proteins. The mRNA of these proteins was detected by semi-quantitative fluorescent PCR. There are 1147 protein spots from RA and 1324 protein spots from OA showed on 2-DE graphs, respectively. We have selected 84 protein spots for MS analysis, and 27 protein spots were successfully identified. We have found that protein isoaspartyl methyltransferase (PIMT) and pirin (iron-binding nuclear protein, PIR) with lower expression in RA, and thioredoxin 1(Trx-1) only expressed in RA may be associated with functions of FLS. Western Blot confirmed the expression of PIMT and pirin lower in RA, and Trx-1 expressed only in RA. The results of semi-quantitative fluorescent PCR are also consistent with 2-DE graphs. PIMT, pirin and Trx-1 affect the functions of FLS in some style and can be the drug targets of RA.

Disease modifying anti-rheumatic activity of the alkaloid montanine on experimental arthritis and fibroblast-like synoviocytes.

PubMed

Farinon, Mirian; Clarimundo, Vanessa S; Pedrazza, Graziele P R; Gulko, Pércio S; Zuanazzi, José A S; Xavier, Ricardo M; de Oliveira, Patricia G

2017-03-15

Montanine is an alkaloid isolated from Rhodophiala bifida bulb with potential anti-arthritic activity. In this context, we evaluated whether montanine has a disease modifying anti-rheumatic activity in two arthritis models and its effect in vitro on lymphocyte proliferation and on invasiveness of fibroblast-like synoviocytes (FLS). Antigen-induced arthritis (AIA) was performed in Balb/C mice with methylated bovine serum albumin, and nociception and leukocytes migration into the knee joint were evaluated. Collagen-induced arthritis (CIA) was performed in DBA/1J mice, and arthritis development and severity were assessed by clinical and histological scoring and articular nociception. Montanine was administered intraperitoneally twice a day. Lymphocyte proliferation stimulated by concanavalin A in 48h was performed with MTT assay, while FLS invasion in 24h was assayed in a Matrigel-coated transwell system. Administration of montanine decreased nociception (P<0.001) and leukocyte articular migration (P<0.001) in mice with AIA. In mice with CIA, treatment with montanine reduced severity of arthritis and joint damage assessed by clinical (P<0.001) and histological (P<0.05) scores and ameliorated articular nociception (P<0.05). In vitro, montanine inhibited lymphocyte proliferation stimulated with ConA (P<0.001) and decreased FLS invasion (P<0.05) by 54%, with an action independent of cytotoxicity. Our findings suggest that montanine can be further explored as an innovative pharmacological approach for autoimmune diseases such as arthritis. Copyright © 2017 Elsevier B.V. All rights reserved.

Three-dimensional joint inversion for magnetotelluric resistivity and static shift distributions in complex media

NASA Astrophysics Data System (ADS)

Sasaki, Yutaka; Meju, Max A.

2006-05-01

Accurate interpretation of magnetotelluric (MT) data in the presence of static shift arising from near-surface inhomogeneities is an unresolved problem in three-dimensional (3-D) inversion. While it is well known in 1-D and 2-D studies that static shift can lead to erroneous interpretation, how static shift can influence the result of 3-D inversion is not fully understood and is relevant to improved subsurface analysis. Using the synthetic data generated from 3-D models with randomly distributed heterogeneous overburden and elongate homogeneous overburden that are consistent with geological observations, this paper examines the effects of near-surface inhomogeneity on the accuracy of 3-D inversion models. It is found that small-scale and shallow depth structures are severely distorted while the large-scale structure is marginally distorted in 3-D inversion not accounting for static shift; thus the erroneous near-surface structure does degrade the reconstruction of smaller-scale structure at any depth. However, 3-D joint inversion for resistivity and static shift significantly reduces the artifacts caused by static shifts and improves the overall resolution, irrespective of whether a zero-sum or Gaussian distribution of static shifts is assumed. The 3-D joint inversion approach works equally well for situations where the shallow bodies are of small size or long enough to allow some induction such that the effects of near-surface inhomogeneity are manifested as a frequency-dependent shift rather than a constant shift.

Linear and quadratic static response functions and structure functions in Yukawa liquids.

PubMed

Magyar, Péter; Donkó, Zoltán; Kalman, Gabor J; Golden, Kenneth I

2014-08-01

We compute linear and quadratic static density response functions of three-dimensional Yukawa liquids by applying an external perturbation potential in molecular dynamics simulations. The response functions are also obtained from the equilibrium fluctuations (static structure factors) in the system via the fluctuation-dissipation theorems. The good agreement of the quadratic response functions, obtained in the two different ways, confirms the quadratic fluctuation-dissipation theorem. We also find that the three-point structure function may be factorizable into two-point structure functions, leading to a cluster representation of the equilibrium triplet correlation function.

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis.

PubMed

Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

2018-02-07

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20-40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

PubMed Central

Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

2018-01-01

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field. PMID:29414875

An improved EMD method for modal identification and a combined static-dynamic method for damage detection

NASA Astrophysics Data System (ADS)

Yang, Jinping; Li, Peizhen; Yang, Youfa; Xu, Dian

2018-04-01

Empirical mode decomposition (EMD) is a highly adaptable signal processing method. However, the EMD approach has certain drawbacks, including distortions from end effects and mode mixing. In the present study, these two problems are addressed using an end extension method based on the support vector regression machine (SVRM) and a modal decomposition method based on the characteristics of the Hilbert transform. The algorithm includes two steps: using the SVRM, the time series data are extended at both endpoints to reduce the end effects, and then, a modified EMD method using the characteristics of the Hilbert transform is performed on the resulting signal to reduce mode mixing. A new combined static-dynamic method for identifying structural damage is presented. This method combines the static and dynamic information in an equilibrium equation that can be solved using the Moore-Penrose generalized matrix inverse. The combination method uses the differences in displacements of the structure with and without damage and variations in the modal force vector. Tests on a four-story, steel-frame structure were conducted to obtain static and dynamic responses of the structure. The modal parameters are identified using data from the dynamic tests and improved EMD method. The new method is shown to be more accurate and effective than the traditional EMD method. Through tests with a shear-type test frame, the higher performance of the proposed static-dynamic damage detection approach, which can detect both single and multiple damage locations and the degree of the damage, is demonstrated. For structures with multiple damage, the combined approach is more effective than either the static or dynamic method. The proposed EMD method and static-dynamic damage detection method offer improved modal identification and damage detection, respectively, in structures.

13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS STRUCTURE AND OVERHEAD CRANE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Approach to Operational Experimental Estimation of Static Stresses of Elements of Mechanical Structures

NASA Astrophysics Data System (ADS)

Sedov, A. V.; Kalinchuk, V. V.; Bocharova, O. V.

2018-01-01

The evaluation of static stresses and strength of units and components is a crucial task for increasing reliability in the operation of vehicles and equipment, to prevent emergencies, especially in structures made of metal and composite materials. At the stage of creation and commissioning of structures to control the quality of manufacturing of individual elements and components, diagnostic control methods are widely used. They are acoustic, ultrasonic, X-ray, radiation methods and others. The using of these methods to control the residual life and the degree of static stresses of units and parts during operation is fraught with great difficulties both in methodology and in instrumentation. In this paper, the authors propose an effective approach of operative control of the degree of static stresses of units and parts of mechanical structures which are in working condition, based on recording the changing in the surface wave properties of a system consisting of a sensor and a controlled environment (unit, part). The proposed approach of low-frequency diagnostics of static stresses presupposes a new adaptive-spectral analysis of a surface wave created by external action (impact). It is possible to estimate implicit stresses of structures in the experiment due to this approach.

Magnetic field effects on charge structure factors of gapped graphene structure

NASA Astrophysics Data System (ADS)

Rezania, Hamed; Tawoose, Nasrin

2018-02-01

We present the behaviors of dynamical and static charge susceptibilities of undoped gapped graphene using the Green's function approach in the context of tight binding model Hamiltonian. Specially, the effects of magnetic field on the plasmon modes of gapped graphene structure are investigated via calculating correlation function of charge density operators. Our results show the increase of magnetic field leads to disappear high frequency plasmon mode for gapped case. We also show that low frequency plasmon mode has not affected by increase of magnetic field and chemical potential. Finally the temperature dependence of static charge structure factor of gapp graphene structure is studied. The effects of both magnetic field and gap parameter on the static structure factor are discusses in details.

Coulomb structures of charged macroparticles in static magnetic traps at cryogenic temperatures

NASA Astrophysics Data System (ADS)

Vasiliev, M. M.; Petrov, O. F.; Statsenko, K. B.

2015-12-01

Electrically charged (up to 107 e) macroscopic superconducting particles with sizes in the micrometer range confined in a static magnetic trap in liquid nitrogen and in nitrogen vapor at temperatures of 77-91 K are observed experimentally. The macroparticles with sizes up to 60 μm levitate in a nonuniform static magnetic field B ~ 2500 G. The formation of strongly correlated structures comprising as many as ~103 particles is reported. The average particle distance in these structures amounts to 475 μm. The coupling parameter and the Lindemann parameter of these structures are estimated to be ~107 and ~0.03, respectively, which is characteristic of strongly correlated crystalline or glasslike structures.

Structural Analysis Peer Review for the Static Display of the Orbiter Atlantis at the Kennedy Space Center Visitors Center

NASA Technical Reports Server (NTRS)

Minute, Stephen A.

2013-01-01

Mr. Christopher Miller with the Kennedy Space Center (KSC) NASA Safety & Mission Assurance (S&MA) office requested the NASA Engineering and Safety Center's (NESC) technical support on March 15, 2012, to review and make recommendations on the structural analysis being performed for the Orbiter Atlantis static display at the KSC Visitor Center. The principal focus of the assessment was to review the engineering firm's structural analysis for lifting and aligning the orbiter and its static display configuration

The Janus kinase inhibitor tofacitinib inhibits TNF-α-induced gliostatin expression in rheumatoid fibroblast-like synoviocytes.

PubMed

Kawaguchi, Yohei; Waguri-Nagaya, Yuko; Tatematsu, Naoe; Oguri, Yusuke; Kobayashi, Masaaki; Nozaki, Masahiro; Asai, Kiyofumi; Aoyama, Mineyoshi; Otsuka, Takanobu

2018-01-15

Gliostatin (GLS) is known to have angiogenic and arthritogenic activity, and GLS expression levels in serum from patients with rheumatoid arthritis (RA) are significantly correlated with the disease activity. Tofacitinib is a novel oral Janus kinase (JAK) inhibitor and is effective in treating RA. However, the mechanism of action of tofacitinib in fibroblast-like synoviocytes (FLSs) has not been elucidated. The purpose of this study was to investigate the modulatory effects of tofacitinib on serum GLS levels in patients with RA and GLS production in FLSs derived from patients with RA. Six patients with RA who had failed therapy with at least one TNF inhibitor and were receiving tofacitinib therapy were included in the study. Serum samples were collected to measure CRP, MMP-3 and GLS expression. FLSs derived from patients with RA were cultured and stimulated by TNFα with or without tofacitinib. GLS expression levels were determined using reverse transcription-polymerase chain reaction (RT-PCR), EIA and immunocytochemistry, and signal transducer and activator of transcription (STAT) protein phosphorylation levels were determined by western blotting. Treatment with tofacitinib decreased serum GLS levels in all patients. GLS mRNA and protein expression levels were significantly increased by treatment with TNF-α alone, and these increases were suppressed by treatment with tofacitinib, which also inhibited TNF-α-induced STAT1 phosphorylation. JAK/STAT activation plays a pivotal role in TNF-α-mediated GLS up-regulation in RA. Suppression of GLS expression in FLSs has been suggested to be one of the mechanisms through which tofacitinib exerts its anti-inflammatory effects.

A photoelectrochemical biosensor for fibroblast-like synoviocyte cell using visible light-activated NCQDs sensitized-ZnO/CH3NH3PbI3 heterojunction.

PubMed

Pang, Xuehui; Zhang, Yong; Pan, Jihong; Zhao, Yanxia; Chen, Yao; Ren, Xiang; Ma, Hongmin; Wei, Qin; Du, Bin

2016-03-15

Based on ZnO nanorods (NRs)/CH3NH3PbI3/nitrogen-doped carbon quantum dots (NCQDs) nanocomposites, the highly sensitive detection of fibroblast-like synoviocyte (FLS) cell was realized by a photoelectrochemical (PEC) biosensor. ZnO/CH3NH3PbI3/NCQDs nanocomposites were exploited as the photo-to-electron generator to produce the signal. CH3NH3PbI3 was spin-coated on ZnO surface after ZnO NRs grew on ITO electrode then by dropping on the modified electrode, NCQDs were diffused and adhered to the surface of ZnO and CH3NH3PbI3. In the presence of EDC/NHS, the combination of CH3NH3PbI3 and NCQDs was achieved by the carboxyl groups (-COOH) and amino groups (-NH2) in the preparation process. Furthermore, the capture probe of FLS cell, CD95 antibody, can be anchored by -COOH and -NH2 groups through EDC/NHS. The specific recognition between the antibody capture probes and cell targets gained high-sensitive detection for FLS cell for the first time. The developed biosensor showed a wide linear range from 1.0 × 10(4)cell/mL to 10 cell/mL and a low detection limit of 2 cell/mL. This kind of biosensor would provide a novel detection strategy for FLS cell. Copyright © 2015 Elsevier B.V. All rights reserved.

Intracellular delivery of poly(I:C) induces apoptosis of fibroblast-like synoviocytes via an unknown dsRNA sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karpus, Olga N.; Hsiao, Cheng-Chih; Kort, Hanneke de

Fibroblast-like synoviocytes (FLS) express functional membranous and cytoplasmic sensors for double-stranded (ds)RNA. Notably, FLS undergo apoptosis upon transfection with the synthetic dsRNA analog poly(I:C). We here studied the mechanism of intracellular poly(I:C) recognition and subsequent cell death in FLS. FLS responded similarly to poly(I:C) or 3pRNA transfection; however, only intracellular delivery of poly(I:C) induced significant cell death, accompanied by upregulation of pro-apoptotic proteins Puma and Noxa, caspase 3 cleavage, and nuclear segregation. Knockdown of the DExD/H-box helicase MDA5 did not affect the response to intracellular poly(I:C); in contrast, knockdown of RIG-I abrogated the response to 3pRNA. Knockdown of the downstreammore » adaptor proteins IPS, STING, and TRIF or inhibition of TBK1 did not affect the response to intracellular poly(I:C), while knockdown of IFNAR blocked intracellular poly(I:C)-mediated signaling and cell death. We conclude that a so far unknown intracellular sensor recognizes linear dsRNA and induces apoptosis in FLS. - Highlights: • Intracellular poly(I:C) and 3pRNA evoke immune responses in FLS. • Only intracellular delivery of poly(I:C) induces FLS apoptosis. • FLS do not require MDA5 for their response to intracellular poly(I:C). • FLS respond to intracellular poly(I:C) independent of IPS and STING. • An unknown intracellular sensor recognizes linear dsRNA in FLS.« less

MiR-338-5p Promotes Inflammatory Response of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via Targeting SPRY1.

PubMed

Yang, Yan; Wang, Yanfeng; Liang, Qingwei; Yao, Lutian; Gu, Shizhong; Bai, Xizhuang

2017-08-01

Our purpose is to study the roles of microRNA-338-5p (miR-338-5p) on the proliferation, invasion, and inflammatory response of fibroblast-like synoviocytes (SFs) in rheumatoid arthritis patients by regulating SPRY1. The target relationship between miR-338-5p and SPRY1 was validated through luciferase reporter system. The expression of miR-338-5p and SPRY1 in synovial tissues and synovial cells were detected using RT-PCR and western blot. The mimics and inhibitors of miR-338-5p were transfected into SFs. MTT, Transwell, and ELISA assays were used to analyze cell proliferation, invasiveness, and the secreted extracellular pro-inflammatory cytokines (such as IL-1a, IL-6, COX2) levels of SFs. MiR-338-5p was highly expressed in rheumatoid arthritis tissues and cells, and directly down-regulated the expression of SPRY1 in the SFs of rheumatoid arthritis patients. Cell proliferation, invasiveness and the expression level of pro-inflammatory cytokines in synovial cells increased after the transfection of miR-338-5p mimics, while the proliferation, invasion and expression level of pro-inflammatory cytokines decreased after the transfection of miR-338-5p inhibitors. In conclusion,miR-338-5p promoted the proliferation, invasion and inflammatory reaction in SFs of rheumatoid arthritis by directly down-regulating SPRY1 expression. J. Cell. Biochem. 118: 2295-2301, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Static aeroelastic behavior of an adaptive laminated piezoelectric composite wing

NASA Technical Reports Server (NTRS)

Weisshaar, T. A.; Ehlers, S. M.

1990-01-01

The effect of using an adaptive material to modify the static aeroelastic behavior of a uniform wing is examined. The wing structure is idealized as a laminated sandwich structure with piezoelectric layers in the upper and lower skins. A feedback system that senses the wing root loads applies a constant electric field to the piezoelectric actuator. Modification of pure torsional deformaton behavior and pure bending deformation are investigated, as is the case of an anisotropic composite swept wing. The use of piezoelectric actuators to create an adaptive structure is found to alter static aeroelastic behavior in that the proper choice of the feedback gain can increase or decrease the aeroelastic divergence speed. This concept also may be used to actively change the lift effectiveness of a wing. The ability to modify static aeroelastic behavior is limited by physical limitations of the piezoelectric material and the manner in which it is integrated into the parent structure.

Numerical study on static component generation from the primary Lamb waves propagating in a plate with nonlinearity

NASA Astrophysics Data System (ADS)

Wan, Xiang; Tse, Peter W.; Zhang, Xuhui; Xu, Guanghua; Zhang, Qing; Fan, Hongwei; Mao, Qinghua; Dong, Ming; Wang, Chuanwei; Ma, Hongwei

2018-04-01

Under the discipline of nonlinear ultrasonics, in addition to second harmonic generation, static component generation is another frequently used nonlinear ultrasonic behavior in non-destructive testing (NDT) and structural health monitoring (SHM) communities. However, most previous studies on static component generation are mainly based on using longitudinal waves. It is desirable to extend static component generation from primary longitudinal waves to primary Lamb waves. In this paper, static component generation from the primary Lamb waves is studied. Two major issues are numerically investigated. First, the mode of static displacement component generated from different primary Lamb wave modes is identified. Second, cumulative effect of static displacement component from different primary Lamb wave modes is also discussed. Our study results show that the static component wave packets generated from the primary S0, A0 and S1 modes share the almost same group velocity equal to the phase velocity of S0 mode tending to zero frequency c plate . The finding indicates that whether the primary mode is S0, A0 or S1, the static components generated from these primary modes always share the nature of S0 mode. This conclusion is also verified by the displacement filed of these static components that the horizontal displacement field is almost uniform and the vertical displacement filed is antisymmetric across the thickness of the plate. The uniform distribution of horizontal displacement filed enables the static component, regardless of the primary Lamb modes, to be a promising technique for evaluating microstructural damages buried in the interior of a structure. Our study also illustrates that the static components are cumulative regardless of whether the phase velocity of the primary and secondary waves is matched or not. This observation indicates that the static component overcomes the limitations of the traditional nonlinear Lamb waves satisfying phase velocity matching condition to achieve cumulative second harmonic generation. This nature also enables the primary Lamb waves excited at a low center frequency to generate static component used for inspecting large-scale structures with micro-scale damages.

Vibration control in statically indeterminate adaptive truss structures

NASA Technical Reports Server (NTRS)

Baycan, C. M.; Utku, Senol; Wada, Ben K.

1993-01-01

In this work vibration control of statically indeterminate adaptive truss structures is investigated. Here, the actuators (i.e., length adjusting devices) that are used for vibration control, work against the axial forces caused by the inertial forces. In statically determinate adaptive trusses no axial force is induced by the actuation. The control problem in statically indeterminate trusses may be dominated by the actuation-induced axial element forces. The creation of actuation-induced axial forces puts the system to a higher energy state, thus aggravates the controls. It is shown that by the usage of sufficient number of slave actuators in addition to the actual control actuators, the actuation-induced axial element forces can be nullified, and the control problem of the statically indeterminate adaptive truss problem is reduced to that of a statically determinate one. It is also shown that the usage of slave actuators saves a great amount of control energy and provides robustness for the controls.

Device to lower NOx in a gas turbine engine combustion system

DOEpatents

Laster, Walter R; Schilp, Reinhard; Wiebe, David J

2015-02-24

An emissions control system for a gas turbine engine including a flow-directing structure (24) that delivers combustion gases (22) from a burner (32) to a turbine. The emissions control system includes: a conduit (48) configured to establish fluid communication between compressed air (22) and the combustion gases within the flow-directing structure (24). The compressed air (22) is disposed at a location upstream of a combustor head-end and exhibits an intermediate static pressure less than a static pressure of the combustion gases within the combustor (14). During operation of the gas turbine engine a pressure difference between the intermediate static pressure and a static pressure of the combustion gases within the flow-directing structure (24) is effective to generate a fluid flow through the conduit (48).

24. CLOSEUP OF MOUNT FOR F1 ENGINE ON STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. CLOSE-UP OF MOUNT FOR F-1 ENGINE ON STATIC TEST TOWER WITH STRUCTURAL DYNAMICS TEST STAND IN DISTANCE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Static Stability in the Global Upper Troposphere and Lower Stratosphere: Observations of Long-term Mean Structure and Variability using GPS Radio Occultation Data

NASA Astrophysics Data System (ADS)

Grise, K. M.; Thompson, D. W.; Birner, T.

2009-12-01

Static stability is a fundamental dynamical quantity that measures the vertical temperature stratification of the atmosphere. The long-term mean static stability field is characterized by the well-known transition from low values in the troposphere to high values in the stratosphere. However, the magnitude and structure of fine-scale static stability features near the tropopause are difficult to discern in temperature data with low vertical resolution. In this study, the authors apply over six years of high vertical resolution Global Positioning System radio occultation temperature profiles to document the long-term mean structure and variability of static stability in the global upper troposphere and lower stratosphere (UTLS). The results of this study demonstrate that a shallow but pronounced maximum in static stability exists just above the tropopause at all latitudes (i.e., the “tropopause inversion layer,” or TIL). This study also uncovers two novel aspects of static stability in the global UTLS. In the tropical lower stratosphere, the results reveal a unique vertically and horizontally varying static stability structure, with maxima located at ~17 km and ~19 km. The upper feature peaks during the NH cold season and has its largest magnitude between 10 and 15 degrees latitude in both hemispheres; the lower feature exhibits a weaker seasonal cycle and is centered at the Equator. The results also demonstrate that the strength of the TIL is closely tied to stratospheric dynamic variability. The magnitude of the TIL is enhanced following sudden stratospheric warmings in the polar regions and the easterly phase of the quasi-biennial oscillation in the tropics.

Static Stability in the Global Upper Troposphere and Lower Stratosphere: Observations of Long-term Mean Structure and Variability using GPS Radio Occultation Data

NASA Astrophysics Data System (ADS)

Grise, Kevin M.; Thompson, David W. J.; Birner, Thomas

2010-05-01

Static stability is a fundamental dynamical quantity that measures the vertical temperature stratification of the atmosphere. The long-term mean static stability field is characterized by the well-known transition from low values in the troposphere to high values in the stratosphere. However, the magnitude and structure of fine-scale static stability features near the tropopause are difficult to discern in temperature data with low vertical resolution. In this study, the authors apply over six years of high vertical resolution Global Positioning System radio occultation temperature profiles to document the long-term mean structure and variability of static stability in the global upper troposphere and lower stratosphere (UTLS). The results of this study demonstrate that a shallow but pronounced maximum in static stability exists just above the tropopause at all latitudes (i.e., the "tropopause inversion layer," or TIL). This study also uncovers two novel aspects of static stability in the global UTLS. In the tropical lower stratosphere, the results reveal a unique vertically and horizontally varying static stability structure, with maxima located at ~17 km and ~19 km. The upper feature peaks during the NH cold season and has its largest magnitude between 10 and 15 degrees latitude in both hemispheres; the lower feature exhibits a weaker seasonal cycle and is centered at the Equator. The results also demonstrate that the strength of the TIL is closely tied to stratospheric dynamic variability. The magnitude of the TIL is enhanced following sudden stratospheric warmings in the polar regions and the easterly phase of the quasi-biennial oscillation in the tropics.

Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations

PubMed Central

Markhoff, Jana; Wieding, Jan; Weissmann, Volker; Pasold, Juliane; Jonitz-Heincke, Anika; Bader, Rainer

2015-01-01

In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM) or electron beam melting (EBM) varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal) and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration. PMID:28793519

Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations.

PubMed

Markhoff, Jana; Wieding, Jan; Weissmann, Volker; Pasold, Juliane; Jonitz-Heincke, Anika; Bader, Rainer

2015-08-24

In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM) or electron beam melting (EBM) varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal) and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration.

Design and Analysis of AN Static Aeroelastic Experiment

NASA Astrophysics Data System (ADS)

Hou, Ying-Yu; Yuan, Kai-Hua; Lv, Ji-Nan; Liu, Zi-Qiang

2016-06-01

Static aeroelastic experiments are very common in the United States and Russia. The objective of static aeroelastic experiments is to investigate deformation and loads of elastic structure in flow field. Generally speaking, prerequisite of this experiment is that the stiffness distribution of structure is known. This paper describes a method for designing experimental models, in the case where the stiffness distribution and boundary condition of a real aircraft are both uncertain. The stiffness distribution form of the structure can be calculated via finite element modeling and simulation calculation and F141 steels and rigid foam are used to make elastic model. In this paper, the design and manufacturing process of static aeroelastic models is presented and a set of experiment model was designed to simulate the stiffness of the designed wings, a set of experiments was designed to check the results. The test results show that the experimental method can effectively complete the design work of elastic model. This paper introduces the whole process of the static aeroelastic experiment, and the experimental results are analyzed. This paper developed a static aeroelasticity experiment technique and established an experiment model targeting at the swept wing of a certain kind of large aspect ratio aircraft.

Overview of the 6 Meter HIAD Inflatable Structure and Flexible TPS Static Load Test Series

NASA Technical Reports Server (NTRS)

Swanson, Greg; Kazemba, Cole; Johnson, Keith; Calomino, Anthony; Hughes, Steve; Cassell, Alan; Cheatwood, Neil

2014-01-01

To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). At the beginning of 2014, a 6m HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify the designs structural performance. The 6m HIAD structure was constructed in a stacked toroid configuration using nine inflatable torus segments composed of fiber reinforced thin films, which were joined together using adhesives and high strength textile woven structural straps to help distribute the loads throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for displacement of the inflatable structure as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The centerbody of the inflatable structure was attached to a pedestal mount as seen in Figure 1. Using an impermeable membrane seal draped over the test article, partial vacuum was pulled beneath the HIAD, resulting in a uniform static pressure load applied to the outer surface. During the test series an extensive amount of instrumentation was used to provide many data sets including: deformed shape, shoulder deflection, strap loads, cord loads, inflation pressures, and applied static load.In this overview, the 6m HIAD static load test series will be discussed in detail, including the 6m HIAD inflatable structure and flexible TPS design, test setup and execution, and finally initial results and conclusions from the test series.

Unequal density effect on static structure factor of coupled electron layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saini, L. K., E-mail: lks@ashd.svnit.ac.in; Nayak, Mukesh G., E-mail: lks@ashd.svnit.ac.in

In order to understand the ordered phase, if any, in a real coupled electron layers (CEL), there is a need to take into account the effect of unequal layer density. Such phase is confirmed by a strong peak in a static structure factor. With the aid of quantum/dynamical version of Singwi, Tosi, Land and Sjölander (so-called qSTLS) approximation, we have calculated the intra- and interlayer static structure factors, S{sub ll}(q) and S{sub 12}(q), over a wide range of density parameter r{sub sl} and interlayer spacing d. In our present study, the sharp peak in S{sub 22}(q) has been found atmore » critical density with sufficiently lower interlayer spacing. Further, to find the resultant effect of unequal density on intra- and interlayer static structure factors, we have compared our results with that of the recent CEL system with equal layer density and isolated single electron layer.« less

The Demand for Higher Education: A Static Structural Approach Accounting for Individual Heterogeneity and Nesting Patterns

ERIC Educational Resources Information Center

Flannery, Darragh; O'Donoghue, Cathal

2013-01-01

In this paper we estimate a structural model of higher education participation and labour choices in a static setting that accounts for individual heterogeneity and possible nesting structures in the decision process. We assume that young people that complete upper secondary education are faced with three choices, go to higher education, not go to…

The quasi-equilibrium response of MOS structures: Quasi-static factor

NASA Astrophysics Data System (ADS)

Okeke, M.; Balland, B.

1984-07-01

The dynamic response of a MOS structure driven into a non-equilibrium behaviour by a voltage ramp is presented. In contrast to Khun's quasi-static technique it is shown that any ramp-driven MOS structure has some degree of non-equilibrium. A quasi staticity factor μAK which serves as a measure of the degree of quasi-equilibrium, has been introduced for the first time. The mathematical model presented in the paper allows a better explanation of the experimental recordings. It is shown that this model could be used to analyse the various features of the response of the structure and that such physical parameters as the generation-rate, trap activation energy, and the effective capture constants could be obtained.

Quasi-static evolution of coronal magnetic fields

NASA Technical Reports Server (NTRS)

Longcope, D. W.; Sudan, R. N.

1992-01-01

A formalism is developed to describe the purely quasi-static part of the evolution of a coronal loop driven by its footpoints. This is accomplished under assumptions of a long, thin loop. The quasi-static equations reveal the possibility for sudden 'loss of equilibrium' at which time the system evolves dynamically rather than quasi-statically. Such quasi-static crises produce high-frequency Alfven waves and, in conjunction with Alfven wave dissipation models, form a viable coronal heating mechanism. Furthermore, an approximate solution to the quasi-static equations by perturbation method verifies the development of small-scale spatial current structure.

Interaction with macrophages attenuates equine fibroblast-like synoviocyte ADAMTS5 (aggrecanase-2) gene expression following inflammatory stimulation.

PubMed

Morgan, Rhiannon E; Clegg, Peter D; Hunt, John A; Innes, John F; Tew, Simon R

2018-03-09

The joint synovium consists of a heterogeneous cell population, chiefly comprised of macrophages, and fibroblast-like synoviocytes (FLS). An inter-species co-culture model was developed to examine interactions between these cells. Equine FLS and the canine macrophage line DH82 were differentially labeled using fluorescent markers and results from direct co-culture compared with those from both indirect co-culture, and conditioned media experiments. The transcript expression of IL-1β, IL-6, ADAMTS4, and ADAMTS5 in each cell type were determined using species-specific qPCR assays. Lipopolysaccharide stimulation of EFLS rapidly increased IL-1β, IL-6, ADAMTS4, and ADAMTS5 mRNAs. The induction of ADAMTS5 was significantly reduced when equine FLS were cultured with DH82 cells directly or indirectly. Exposure of equine FLS to denatured conditioned media also significantly reduced ADAMTS5 induction. DH82 cells increased interleukin-1β expression substantially following LPS stimulation. However, knockdown of interleukin-1β in DH82 cells, or inhibition of NF-κB in equine FLS prior to co-culture did not change the inhibitory effect on equine FLS ADAMTS5 gene expression. This work indicates that macrophages can influence FLS gene expression through a soluble mediator, and modulate the expression of an enzyme critical in osteoarthritis pathology during inflammatory stimulation. © 2018 The Authors. Journal of Orthopaedic Research® Published by WileyPeriodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 9999:1-8, 2018. © 2018 The Authors. Journal of Orthopaedic Research® Published by WileyPeriodicals, Inc. on behalf of the Orthopaedic Research Society.

Metabolomic Elucidation of the Effects of Curcumin on Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

PubMed Central

Hwang, Jiwon; Kim, Jungyeon; Lee, You Sun; Koh, Eun-Mi; Kim, Kyoung Heon; Cha, Hoon-Suk

2015-01-01

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease characterized by synovial inflammation and joint disability. Curcumin is known to be effective in ameliorating joint inflammation in RA. To obtain new insights into the effect of curcumin on primary fibroblast-like synoviocytes (FLS, N = 3), which are key effector cells in RA, we employed gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS)-based metabolomics. Metabolomic profiling of tumor necrosis factor (TNF)-α-stimulated and curcumin-treated FLS was performed using GC/TOF-MS in conjunction with univariate and multivariate statistical analyses. A total of 119 metabolites were identified. Metabolomic analysis revealed that metabolite profiles were clearly distinct between TNF-α-stimulated vs. the control group (not stimulated by TNF-α or curcumin). Treatment of FLS with curcumin showed that the metabolic perturbation by TNF-α could be reversed to that of the control group to a considerable extent. Curcumin-treated FLS had higher restoration of amino acid and fatty acid metabolism, as indicated by the prominent metabolic restoration of intermediates of amino acid and fatty acid metabolism, compared with that observed in TNF-α-stimulated FLS. In particular, the abundance of glycine, citrulline, arachidonic acid, and saturated fatty acids in TNF-α-stimulated FLS was restored to the control level after treatment with curcumin, suggesting that the effect of curcumin on preventing joint inflammation may be elucidated with the levels of these metabolites. Our results suggest that GC/TOF-MS-based metabolomic investigation using FLS has the potential for discovering the mechanism of action of curcumin and new targets for therapeutic drugs in RA. PMID:26716989

Metabolomic Elucidation of the Effects of Curcumin on Fibroblast-Like Synoviocytes in Rheumatoid Arthritis.

PubMed

Ahn, Joong Kyong; Kim, Sooah; Hwang, Jiwon; Kim, Jungyeon; Lee, You Sun; Koh, Eun-Mi; Kim, Kyoung Heon; Cha, Hoon-Suk

2015-01-01

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease characterized by synovial inflammation and joint disability. Curcumin is known to be effective in ameliorating joint inflammation in RA. To obtain new insights into the effect of curcumin on primary fibroblast-like synoviocytes (FLS, N = 3), which are key effector cells in RA, we employed gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS)-based metabolomics. Metabolomic profiling of tumor necrosis factor (TNF)-α-stimulated and curcumin-treated FLS was performed using GC/TOF-MS in conjunction with univariate and multivariate statistical analyses. A total of 119 metabolites were identified. Metabolomic analysis revealed that metabolite profiles were clearly distinct between TNF-α-stimulated vs. the control group (not stimulated by TNF-α or curcumin). Treatment of FLS with curcumin showed that the metabolic perturbation by TNF-α could be reversed to that of the control group to a considerable extent. Curcumin-treated FLS had higher restoration of amino acid and fatty acid metabolism, as indicated by the prominent metabolic restoration of intermediates of amino acid and fatty acid metabolism, compared with that observed in TNF-α-stimulated FLS. In particular, the abundance of glycine, citrulline, arachidonic acid, and saturated fatty acids in TNF-α-stimulated FLS was restored to the control level after treatment with curcumin, suggesting that the effect of curcumin on preventing joint inflammation may be elucidated with the levels of these metabolites. Our results suggest that GC/TOF-MS-based metabolomic investigation using FLS has the potential for discovering the mechanism of action of curcumin and new targets for therapeutic drugs in RA.

Suppression of complete Freund's adjuvant-induced adjuvant arthritis by cobratoxin.

PubMed

Liu, Yan-Li; Lin, Hai-Ming; Zou, Rong; Wu, Jun-Chao; Han, Rong; Raymond, Laurence N; Reid, Paul F; Qin, Zheng-Hong

2009-02-01

Cobratoxin (CTX), the long-chain alpha-neurotoxin from Thailand cobra venom, has been demonstrated to have analgesic action in rodent pain models. The present study evaluated the anti-inflammatory and anti-nociceptive effects of CTX on adjuvant arthritis (AA) in rats. Arthritis was induced by injection of complete Freund's adjuvant (CFA) in rats. Paw swelling and hyperalgesia of AA rats were measured at various times after CFA administration. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-2 (IL-2) and interleukin-10 (IL-10) levels in serum were determined with ELISA. Histopathological changes in synoviocytes were examined under a microscope. Involvement of the cholinergic system in the effects of CTX was examined by pretreatment of animals with the alpha(7) nicotinic receptor (alpha(7)-nAChR) antagonist methyllycaconitine (MLA). CFA induced marked paw swelling and reduced thresholds of mechanical and cold-induced paw withdrawal. The levels of TNF-alpha, IL-1 and IL-2 in the serum of AA rats were increased, whereas the level of IL-10 was decreased. Histopathological examination of synoviocytes showed pronounced inflammation and accumulation of collagen. The administration of CTX (17.0 microg/kg, ip) significantly reduced paw swelling and mechanical and thermal hyperalgesia. CTX also reduced the production of TNF-alpha, IL-1, and IL-2 but increased the production of IL-10 and altered pathohistological changes. The analgesic and anti-inflammatory efficacy of CTX was significantly reduced by MLA (3 mg/kg, sc). These results indicate that CTX has a beneficial effect on CFA-induced arthritis by modulating the production of inflammatory cytokines. alpha(7)-nAChR appears to mediate the anti-nociceptive and anti-inflammatory actions of CTX.

Cyanidin-3-glucoside inhibits inflammatory activities in human fibroblast-like synoviocytes and in mice with collagen-induced arthritis.

PubMed

Sun, Yan; Li, Lingling

2018-05-19

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint tissue inflammation. Cyanidin-3-glucoside (C3G) is a major component in the flavonoid family and has shown anti-inflammatory, anti-oxidant and anti-tumor activity. In this study, we investigated the effects of C3G on lipopolysaccharides (LPS)-induced inflammation on human rheumatoid fibroblast-like synoviocytes (FLS) and on collagen-induced arthritis (CIA) mice model. We treated FLS with C3G followed by LPS induction, the expressions of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and IL-6 and the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathway were analyzed. CIA was induced in mice and the arthritic mice were treated with C3G for 3 weeks. The disease severity was compared between control and C3G treated mice. The serum levels of TNF-α, IL-1β and IL-6 were analyzed by ELISA. C3G inhibited LPS-induced TNF-α, IL-1β and IL-6 expression in FLS. Moreover, C3G inhibited LPS-induced p65 production and IκBa, p38, ERK and JNK phosphorylation. Administration of C3G significantly attenuated disease in mice with CIA and decreased the serum level of TNF-α, IL-1β and IL-6. C3G inhibited LPS-induced inflammation in human FLS by inhibiting activation of NF-κB and MAPK signaling pathway. C3G exhibited therapeutic effects in mice with CIA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The A3 adenosine receptor agonist CF502 inhibits the PI3K, PKB/Akt and NF-kappaB signaling pathway in synoviocytes from rheumatoid arthritis patients and in adjuvant-induced arthritis rats.

PubMed

Ochaion, A; Bar-Yehuda, S; Cohen, S; Amital, H; Jacobson, K A; Joshi, B V; Gao, Z G; Barer, F; Patoka, R; Del Valle, L; Perez-Liz, G; Fishman, P

2008-08-15

The A(3) adenosine receptor (A(3)AR) is over-expressed in inflammatory cells and was defined as a target to combat inflammation. Synthetic agonists to this receptor, such as IB-MECA and Cl-IB-MECA, exert an anti-inflammatory effect in experimental animal models of adjuvant- and collagen-induced arthritis. In this study we present a novel A(3)AR agonist, CF502, with high affinity and selectivity at the human A(3)AR. CF502 induced a dose dependent inhibitory effect on the proliferation of fibroblast-like synoviocytes (FLS) via de-regulation of the nuclear factor-kappa B (NF-kappaB) signaling pathway. Furthermore, CF502 markedly suppressed the clinical and pathological manifestations of adjuvant-induced arthritis (AIA) in a rat experimental model when given orally at a low dose (100 microg/kg). As is typical of other G-protein coupled receptors, the A(3)AR expression level was down-regulated shortly after treatment with agonist CF502 in paw and in peripheral blood mononuclear cells (PBMCs) derived from treated AIA animals. Subsequently, a decrease in the expression levels of protein kinase B/Akt (PKB/Akt), IkappaB kinase (IKK), I kappa B (IkappaB), NF-kappaB and tumor necrosis factor-alpha (TNF-alpha) took place. In addition, the expression levels of glycogen synthase kinase-3 beta (GSK-3beta), beta-catenin, and poly(ADP-ribose)polymerase (PARP), known to control the level and activity of NF-kappaB, were down-regulated upon treatment with CF502. Taken together, CF502 inhibits FLS growth and the inflammatory manifestations of arthritis, supporting the development of A(3)AR agonists for the treatment of rheumatoid arthritis.

Interleukin-35 upregulates OPG and inhibits RANKL in mice with collagen-induced arthritis and fibroblast-like synoviocytes.

PubMed

Li, Y; Li, D; Li, Y; Wu, S; Jiang, S; Lin, T; Xia, L; Shen, H; Lu, J

2016-04-01

IL-35 is a novel anti-inflammatory cytokine, but the exact role of IL-35 in the progression of RA remains unclear, especially associated with osteoporosis and bone erosion. The present research has not been reported. Our purpose is to study how IL-35 affects RA bone destruction. This study investigated the effect of interleukin-35 (IL-35) on OPG and RANKL expression in collagen-induced arthritis (CIA) in rats and in cultured fibroblast-like synoviocytes (FLS). Thirty DBA/1J mice were randomly assigned to three groups (n = 10 per group): the control group, the CIA group, and the CIA + IL-35 group. Collagen-induced arthritis was induced by immunization with collagen. IL-35 was intraperitoneally injected daily for 10 days, starting from the 24(th) day after immunization. FLS cells were isolated and cultured from CIA. The expression of IL-17, RANKL, and OPG was determined by RT-PCR and Western blot. Each experiment was repeated three times. CIA mice exhibited arthritis symptoms on day 24, followed by a rapid progression of arthritis. The expression of IL-17 and RANKL was increased and the expression of OPG was decreased in CIA mice compared with control mice. IL-35 treatment inhibited the development of arthritis in CIA mice, accompanied by a decrease in the expression of IL-17 and RANKL and an increase in the expression of OPG. Furthermore, IL-35 dose-dependently inhibited the expression of RANKL and increased the expression of OPG in cultured FLS cells. IL-35 inhibits RANKL expression and increases OPG expression in CIA mice. IL-35 may be used for treating rheumatoid arthritis.

Prior to extension, Transcriptomes of fibroblast-like Synoviocytes from extended and Polyarticular juvenile idiopathic arthritis are indistinguishable.

PubMed

Brescia, AnneMarie C; Simonds, Megan M; McCahan, Suzanne M; Sullivan, Kathleen E; Rose, Carlos D

2018-01-08

Our intent was to identify differences between the transcriptome of fibroblast-like synoviocytes (FLS) in oligoarticular juvenile idiopathic arthritis (JIA) before extension when compared to persistent subtype of JIA, when the two are clinically indistinguishable. Additionally, we sought to determine if differences between the transcriptomes of FLS from extended-to-be and polyarticular course JIA could be detected. Our hypothesis was that intrinsic differences in the transcriptome of the FLS from extended-to-be JIA would distinguish them from persistent oligoarticular JIA, before the course is clinically apparent. Global gene expression was defined in cultured FLS from 6 controls, 12 JIA with persistent course, 7 JIA prior to extension (extended-to-be), 4 JIA with extended course and 6 polyarticular onset, using Affymetrix Human GeneChips 133plus2.0. Bioconductor Linear Models for Microarray Analysis revealed 22 probesets with differential expression between persistent and extended-to-be FLS at 15% FDR, however only 2 probesets distinguished extended-to-be from extended and none distinguished extended-to-be and polyarticular at 15% FDR. Differences in extended and polyarticular gene expression profiles were not detected. Confirmation of select genes was done on the RNA level by RT-qPCR and on the protein level in synovial fluid by ELISA. The transcriptome of FLS from extended-to-be juvenile idiopathic arthritis is distinct from persistent course before a clinical distinction can be made. Additionally, the transcriptome of extended-to-be and polyarticular course, including those who have already extended, are indistinguishable. These gene expression data suggest that FLS already reflect a polyarticular behavior early in disease course, suggesting that extended-to-be may be "latent polyarticular" at onset. These differences can be used to develop early biomarkers of disease course, allowing for better-informed treatment decisions.

A novel NF-κB/YY1/microRNA-10a regulatory circuit in fibroblast-like synoviocytes regulates inflammation in rheumatoid arthritis

PubMed Central

Mu, Nan; Gu, Jintao; Huang, Tonglie; Zhang, Cun; Shu, Zhen; Li, Meng; Hao, Qiang; Li, Weina; Zhang, Wangqian; Zhao, Jinkang; Zhang, Yong; Huang, Luyu; Wang, Shuning; Jin, Xiaohang; Xue, Xiaochang; Zhang, Wei; Zhang, Yingqi

2016-01-01

The main etiopathogenesis of rheumatoid arthritis (RA) is overexpressed inflammatory cytokines and tissue injury mediated by persistent NF-κB activation. MicroRNAs widely participate in the regulation of target gene expression and play important roles in various diseases. Here, we explored the mechanisms of microRNAs in RA. We found that microRNA (miR)-10a was downregulated in the fibroblast-like synoviocytes (FLSs) of RA patients compared with osteoarthritis (OA) controls, and this downregulation could be triggered by TNF-α and IL-1β in an NF-κB-dependent manner through promoting the expression of the YingYang 1 (YY1) transcription factor. Downregulated miR-10a could accelerate IκB degradation and NF-κB activation by targeting IRAK4, TAK1 and BTRC. This miR-10a-mediated NF-κB activation then significantly promoted the production of various inflammatory cytokines, including TNF-α, IL-1β, IL-6, IL-8, and MCP-1, and matrix metalloproteinase (MMP)-1 and MMP-13. In addition, transfection of a miR-10a inhibitor accelerated the proliferation and migration of FLSs. Collectively, our data demonstrates the existence of a novel NF-κB/YY1/miR-10a/NF-κB regulatory circuit that promotes the excessive secretion of NF-κB-mediated inflammatory cytokines and the proliferation and migration of RA FLSs. Thus, miR-10a acts as a switch to control this regulatory circuit and may serve as a diagnostic and therapeutic target for RA treatment. PMID:26821827

MDM4 overexpression contributes to synoviocyte proliferation in patients with rheumatoid arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Nanwei; Wang, Yuji, E-mail: yujiwang@sohu.com; State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433

Research highlights: {yields} Elevated MDM4 mRNA and protein levels in FLS from patients with RA and OA. {yields} Strong MDM4 staining in synovial cells of inflammatory synovium. {yields} MDM4 knockdown increased p53 and p21 levels, and inhibited the proliferation of RA FLS. {yields} MDM4 overexpression increased p53 while decreased p21 levels, and promoted the growth of RA FLS. -- Abstract: Rheumatoid arthritis (RA) is a chronic autoimmune disease with features of inflammatory cell infiltration, synovial cell invasive proliferation, and ultimately, irreversible joint destruction. It has been reported that the p53 pathway is involved in RA pathogenesis. MDM4/MDMX is a majormore » negative regulator of p53. To determine whether MDM4 contributes to RA pathogenesis, MDM4 mRNA and protein expression were assessed in fibroblast-like synoviocytes (FLS) by real-time PCR, western blotting, and in synovial tissues by immunohistochemistry. Furthermore, MDM4 was knocked down and overexpressed by lentivirus-mediated expression, and the proliferative capacity of FLS was determined by MTS assay. We found that cultured FLS from RA and osteoarthritis (OA) patients exhibited higher levels of MDM4 mRNA and protein expression than those from trauma controls. MDM4 protein was highly expressed in the synovial lining and sublining cells from both types of arthritis. Finally, MDM4 knockdown inhibited the proliferation of RA FLS by enhancing functional p53 levels while MDM4 overexpression promoted the growth of RA FLS by inhibiting p53 effects. Taken together, our results suggest that the abundant expression of MDM4 in FLS may contribute to the hyperplasia phenotype of RA synovial tissues.« less

The effects of arctigenin on human rheumatoid arthritis fibroblast-like synoviocytes.

PubMed

Liu, Hongbin; Yang, Yang; Cai, Xiaosong; Gao, Yunlong; Du, Jun; Chen, Shuo

2015-08-01

Rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) play an important role in the initiation and progression of RA, which are resistant to apoptosis and proliferate in an anchorage-independent manner. The effects of arctigenin on the proliferation and apoptosis of RAFLSs were explored. Arctigenin (0-160 µM) was used to treat RAFLSs for 48 h. Cell viability and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay and annexin V/propidium iodide staining. Western blot analysis was performed to detect the changes in apoptosis-related genes. Arctigenin decreased cell viability by 23, 30, and 38% at the dose of 10, 20, and 30 µM, respectively. The half maximal inhibitory concentration (IC50) of arctignein on RAFLSs was about 38 µM. Moreover, 9, 15, and 21% of RAFLSs are induced apoptosis by 10, 20, and 30 µM of arctigenin. The apoptotic response was due to the loss of mitochondrial membrane potential, coupled with the release of cytochrome C into cytoplasm, the up-regulation of pro-apoptotic protein, Bax, and down-regulation of antiapoptotic protein, B cell lymphoma 2 (Bcl-2). The activation of mitochondrial pathway in arctigenin-treated RAFLSs induced the cleavage of caspase-9, caspase-3, and poly (ADP-ribose) polymerase (PARP). Additionally, arctigenin inhibited the nuclear translocation of p65, decreased the degradation of inhibitor of kappa B alpha (IκBα), and attenuated the phosphorylation of Akt. Our results reveal that arctigenin inhibits cell proliferation and induces mitochondrial apoptosis of RAFLSs, which is associated with the modulation of NF-κB and Akt signaling pathways.

Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

PubMed

Hetsroni, Iftach; Nyska, Meir; Ben-Sira, David; Mann, Gideon; Segal, Ofer; Maoz, Guy; Ayalon, Moshe

2010-03-01

In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

An Aeroelastic Analysis of a Thin Flexible Membrane

NASA Technical Reports Server (NTRS)

Scott, Robert C.; Bartels, Robert E.; Kandil, Osama A.

2007-01-01

Studies have shown that significant vehicle mass and cost savings are possible with the use of ballutes for aero-capture. Through NASA's In-Space Propulsion program, a preliminary examination of ballute sensitivity to geometry and Reynolds number was conducted, and a single-pass coupling between an aero code and a finite element solver was used to assess the static aeroelastic effects. There remain, however, a variety of open questions regarding the dynamic aeroelastic stability of membrane structures for aero-capture, with the primary challenge being the prediction of the membrane flutter onset. The purpose of this paper is to describe and begin addressing these issues. The paper includes a review of the literature associated with the structural analysis of membranes and membrane utter. Flow/structure analysis coupling and hypersonic flow solver options are also discussed. An approach is proposed for tackling this problem that starts with a relatively simple geometry and develops and evaluates analysis methods and procedures. This preliminary study considers a computationally manageable 2-dimensional problem. The membrane structural models used in the paper include a nonlinear finite-difference model for static and dynamic analysis and a NASTRAN finite element membrane model for nonlinear static and linear normal modes analysis. Both structural models are coupled with a structured compressible flow solver for static aeroelastic analysis. For dynamic aeroelastic analyses, the NASTRAN normal modes are used in the structured compressible flow solver and 3rd order piston theories were used with the finite difference membrane model to simulate utter onset. Results from the various static and dynamic aeroelastic analyses are compared.

Experimental thermal mechanics of deployable boom structures

NASA Technical Reports Server (NTRS)

Predmore, R.

1972-01-01

An apparatus was developed for thermal distortion measurements on deployable boom structures. The calibration procedure and thermal static bending plus twist measurements are considered. The thermal mechanics test facility is described. A table is presented for several examples of spacecraft applications of thermal static distortion measurements on 3-m deployable booms.

Quark structure of static correlators in high temperature QCD

NASA Astrophysics Data System (ADS)

Bernard, Claude; DeGrand, Thomas A.; DeTar, Carleton; Gottlieb, Steven; Krasnitz, A.; Ogilvie, Michael C.; Sugar, R. L.; Toussaint, D.

1992-07-01

We present results of numerical simulations of quantum chromodynamics at finite temperature with two flavors of Kogut-Susskind quarks on the Intel iPSC/860 parallel processor. We investigate the properties of the objects whose exchange gives static screening lengths by reconstructing their correlated quark-antiquark structure.

14 CFR 29.610 - Lightning and static electricity protection.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

14 CFR 29.610 - Lightning and static electricity protection.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

14 CFR 29.610 - Lightning and static electricity protection.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

14 CFR 29.610 - Lightning and static electricity protection.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

14 CFR 29.610 - Lightning and static electricity protection.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Lightning and static electricity protection... § 29.610 Lightning and static electricity protection. (a) The rotorcraft structure must be protected... electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk of electric...

Static aeroelastic analysis and tailoring of a single-element racing car wing

NASA Astrophysics Data System (ADS)

Sadd, Christopher James

This thesis presents the research from an Engineering Doctorate research programme in collaboration with Reynard Motorsport Ltd, a manufacturer of racing cars. Racing car wing design has traditionally considered structures to be rigid. However, structures are never perfectly rigid and the interaction between aerodynamic loading and structural flexibility has a direct impact on aerodynamic performance. This interaction is often referred to as static aeroelasticity and the focus of this research has been the development of a computational static aeroelastic analysis method to improve the design of a single-element racing car wing. A static aeroelastic analysis method has been developed by coupling a Reynolds-Averaged Navier-Stokes CFD analysis method with a Finite Element structural analysis method using an iterative scheme. Development of this method has included assessment of CFD and Finite Element analysis methods and development of data transfer and mesh deflection methods. Experimental testing was also completed to further assess the computational analyses. The computational and experimental results show a good correlation and these studies have also shown that a Navier-Stokes static aeroelastic analysis of an isolated wing can be performed at an acceptable computational cost. The static aeroelastic analysis tool was used to assess methods of tailoring the structural flexibility of the wing to increase its aerodynamic performance. These tailoring methods were then used to produce two final wing designs to increase downforce and reduce drag respectively. At the average operating dynamic pressure of the racing car, the computational analysis predicts that the downforce-increasing wing has a downforce of C[1]=-1.377 in comparison to C[1]=-1.265 for the original wing. The computational analysis predicts that the drag-reducing wing has a drag of C[d]=0.115 in comparison to C[d]=0.143 for the original wing.

Dynamic Breaking Tests of Airplane Parts

NASA Technical Reports Server (NTRS)

Hertel, Heinrich

1933-01-01

The static stresses of airplane parts, the magnitude of which can be determined with the aid of static load assumptions, are mostly superposed by dynamic stresses, the magnitude of which has been but little explored. The object of the present investigation is to show how the strength of airplane parts can best be tested with respect to dynamic stresses with and without superposed static loading, and to what extent the dynamic strength of the parts depends on their structural design. Experimental apparatus and evaluation methods were developed and tried for the execution of vibration-strength tests with entire structural parts both with and without superposed static loading. Altogether ten metal spars and spar pieces and two wooden spars were subjected to vibration breaking tests.

A procedure obtaining stiffnesses and masses of a structure from vibration modes and substructure static test data

NASA Technical Reports Server (NTRS)

Edighoffer, H. H.

1979-01-01

A component mode desynthesis procedure is developed for determining the unknown vibration characteristics of a structural component (i.e., a launch vehicle) given the vibration characteristics of a structural system composed of that component combined with a known one (i.e., a payload). At least one component static test has to be performed. These data are used in conjunction with the system measured frequencies and mode shapes to obtain the vibration characteristics of each component. The flight dynamics of an empty launch vehicle can be determined from measurements made on a vehicle/payload combination in conjunction with a static test on the payload.

Static shape control for flexible structures

NASA Technical Reports Server (NTRS)

Rodriguez, G.; Scheid, R. E., Jr.

1986-01-01

An integrated methodology is described for defining static shape control laws for large flexible structures. The techniques include modeling, identifying and estimating the control laws of distributed systems characterized in terms of infinite dimensional state and parameter spaces. The models are expressed as interconnected elliptic partial differential equations governing a range of static loads, with the capability of analyzing electromagnetic fields around antenna systems. A second-order analysis is carried out for statistical errors, and model parameters are determined by maximizing an appropriate defined likelihood functional which adjusts the model to observational data. The parameter estimates are derived from the conditional mean of the observational data, resulting in a least squares superposition of shape functions obtained from the structural model.

Structural integrity of a confinement vessel for testing nuclear fuels for space propulsion

NASA Astrophysics Data System (ADS)

Bergmann, V. L.

Nuclear propulsion systems for rockets could significantly reduce the travel time to distant destinations in space. However, long before such a concept can become reality, a significant effort must be invested in analysis and ground testing to guide the development of nuclear fuels. Any testing in support of development of nuclear fuels for space propulsion must be safely contained to prevent the release of radioactive materials. This paper describes analyses performed to assess the structural integrity of a test confinement vessel. The confinement structure, a stainless steel pressure vessel with bolted flanges, was designed for operating static pressures in accordance with the ASME Boiler and Pressure Vessel Code. In addition to the static operating pressures, the confinement barrier must withstand static overpressures from off-normal conditions without releasing radioactive material. Results from axisymmetric finite element analyses are used to evaluate the response of the confinement structure under design and accident conditions. For the static design conditions, the stresses computed from the ASME code are compared with the stresses computed by the finite element method.

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

NASA Astrophysics Data System (ADS)

Belov, Nikolay; Yugov, Nikolay; Kopanitsa, Dmitry; Kopanitsa, Georgy; Yugov, Alexey; Kaparulin, Sergey; Plyaskin, Andrey; Kalichkina, Anna; Ustinov, Artyom

2016-01-01

When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

Static structure of a pointed charged drop

NASA Astrophysics Data System (ADS)

Fernandez de La Mora, Juan

2017-11-01

The static equilibrium structure of an equipotential drop with two symmetric Taylor cones is computed by assigning a charge distribution along the z axis q (z) = ∑Bn (L2 -z2)n + 1 / 2 . Taylor's local equilibrium at the poles z = L , - L fixes two of the Bn coefficients as a function of the other, determined by minimizing stress imbalance. Just two optimally chosen terms in the Bn expansion yield imperceptible errors. Prior work has argued that an exploding drop initially carrying Rayleigh's charge qR is quasi static. Paradoxically, quasi-static predictions on the size of the progeny drops emitted during a Coulombic explosion disagree with observations. The static drop structure found here also models poorly a Coulomb explosion having an equatorial over polar length ratio (0.42) and the a drop charge exceeding those observed (0.28-0.36 and qR / 2). Our explanation for this paradox is that, while the duration tc of a Coulomb explosion is much larger than the charge relaxation time, the dynamic time scale for drop elongation is typically far longer than tc. Therefore, the pressure distribution within the exploding drop is not uniform. A similar analysis for a drop in an external field fits well the experimental shape.

Optimum structural design with static aeroelastic constraints

NASA Technical Reports Server (NTRS)

Bowman, Keith B; Grandhi, Ramana V.; Eastep, F. E.

1989-01-01

The static aeroelastic performance characteristics, divergence velocity, control effectiveness and lift effectiveness are considered in obtaining an optimum weight structure. A typical swept wing structure is used with upper and lower skins, spar and rib thicknesses, and spar cap and vertical post cross-sectional areas as the design parameters. Incompressible aerodynamic strip theory is used to derive the constraint formulations, and aerodynamic load matrices. A Sequential Unconstrained Minimization Technique (SUMT) algorithm is used to optimize the wing structure to meet the desired performance constraints.

Fatigue tests on big structure assemblies of concorde aircraft

NASA Technical Reports Server (NTRS)

Nguyen, V. P.; Perrais, J. P.

1972-01-01

Fatigue tests on structural assemblies of the Concorde supersonic transport aircraft are reported. Two main sections of the aircraft were subjected to pressure, mechanical load, and thermal static tests. The types of fatigue tests conducted and the results obtained are discussed. It was concluded that on a supersonic aircraft whose structural weight is a significant part of the weight analysis, many fatigue and static strength development tests should be made and fatigue and thermal tests of the structures are absolutely necessary.

A discourse on sensitivity analysis for discretely-modeled structures

NASA Technical Reports Server (NTRS)

Adelman, Howard M.; Haftka, Raphael T.

1991-01-01

A descriptive review is presented of the most recent methods for performing sensitivity analysis of the structural behavior of discretely-modeled systems. The methods are generally but not exclusively aimed at finite element modeled structures. Topics included are: selections of finite difference step sizes; special consideration for finite difference sensitivity of iteratively-solved response problems; first and second derivatives of static structural response; sensitivity of stresses; nonlinear static response sensitivity; eigenvalue and eigenvector sensitivities for both distinct and repeated eigenvalues; and sensitivity of transient response for both linear and nonlinear structural response.

Isolation of xanthone and benzophenone derivatives from Cyclopia genistoides (L.) Vent. (honeybush) and their pro-apoptotic activity on synoviocytes from patients with rheumatoid arthritis.

PubMed

Kokotkiewicz, Adam; Luczkiewicz, Maria; Pawlowska, Justyna; Luczkiewicz, Piotr; Sowinski, Pawel; Witkowski, Jacek; Bryl, Ewa; Bucinski, Adam

2013-10-01

A fast and efficient method for the isolation of the C-glucosidated xanthones mangiferin and isomangiferin from the South-African plant Cyclopia genistoides was developed for the first time. The procedure involved extraction, liquid-liquid partitioning with ethyl acetate and subsequent precipitation of mangiferin and isomangiferin from methanol and acetonitrile-water fractions, respectively. Additionally, two benzophenone derivatives: 3-C-β-glucosides of maclurin and iriflophenone, were isolated from C. genistoides extracts using semi-preparative HPLC. Apart from the above, the isolation procedure also yielded hesperidin and small amounts of luteolin. The structures of the compounds were determined by 1D and 2D NMR experiments and/or LC-DAD-ESI-MS. The selected Cyclopia constituents were screened for pro-apoptotic activity on TNF-α-stimulated synovial cells isolated from rheumatoid arthritis patients. The strongest effect, measured as percent of apoptotic cells, was recorded for isomangiferin (75%), followed by iriflophenone 3-C-β-glucoside (71%), hesperidin (67%) and mangiferin (65%). The results are encouraging for further studies on the use of the above compounds in the treatment of rheumatoid arthritis. © 2013.

Modeling the Car Crash Crisis Management System Using HiLA

NASA Astrophysics Data System (ADS)

Hölzl, Matthias; Knapp, Alexander; Zhang, Gefei

An aspect-oriented modeling approach to the Car Crash Crisis Management System (CCCMS) using the High-Level Aspect (HiLA) language is described. HiLA is a language for expressing aspects for UML static structures and UML state machines. In particular, HiLA supports both a static graph transformational and a dynamic approach of applying aspects. Furthermore, it facilitates methodologically turning use case descriptions into state machines: for each main success scenario, a base state machine is developed; all extensions to this main success scenario are covered by aspects. Overall, the static structure of the CCCMS is modeled in 43 classes, the main success scenarios in 13 base machines, the use case extensions in 47 static and 31 dynamic aspects, most of which are instantiations of simple aspect templates.

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

Test stand for Titan 34D SRM static firing

NASA Technical Reports Server (NTRS)

Glozman, Vladimir; Shipway, George

1988-01-01

An existing liquid engine test stand at the AF Astronautics Laboratory was refurbished and extensively modified to accommodate the static firing of the Titan 34D solid rocket motor (SRM) in the vertical nozzle down orientation. The main load restraint structure was designed and built to secure the SRM from lifting off during the firing. In addition, the structure provided weather protection, temperature conditioning of the SRM, and positioning of the measurement and recording equipment. The structure was also used for stacking/de-stacking of SRM segments and other technological processes. The existing stand, its foundation and anchorage were thoroughly examined and reanalyzed. Necessary stand modifications were carried out to comply with the requirements of the Titan 34D SRM static firing.

Evaluation of flawed composite structural components under static and cyclic loading. [fatigue life of graphite-epoxy composite materials

NASA Technical Reports Server (NTRS)

Porter, T. R.

1979-01-01

The effects of initial defects on the fatigue and fracture response of graphite-epoxy composite laminates are presented. The structural laminates investigated were a typical angle ply laminate, a polar/hoop wound pressure vessel laminate, and a typical engine fan blade laminate. Defects investigated were full and half penetration circular holes, full and half penetration slits, and countersink holes. The effects of the defect size and type on the static fracture strength, fatigue performance, and residual static strength are shown as well as the results of loadings on damage propagation in composite laminates. The data obtained were used to define proof test levels as a qualification procedure in composite structure subjected to cyclic loading.

Adaptive wing static aeroelastic roll control

NASA Astrophysics Data System (ADS)

Ehlers, Steven M.; Weisshaar, Terrence A.

1993-09-01

Control of the static aeroelastic characteristics of a swept uniform wing in roll using an adaptive structure is examined. The wing structure is modeled as a uniform beam with bending and torsional deformation freedom. Aerodynamic loads are obtained from strip theory. The structure model includes coefficients representing torsional and bending actuation provided by embedded piezoelectric material layers. The wing is made adaptive by requiring the electric field applied to the piezoelectric material layers to be proportional to the wing root loads. The proportionality factor, or feedback gain, is used to control static aeroelastic rolling properties. Example wing configurations are used to illustrate the capabilities of the adaptive structure. The results show that rolling power, damping-in-roll and aileron effectiveness can be controlled by adjusting the feedback gain. And that dynamic pressure affects the gain required. Gain scheduling can be used to set and maintain rolling properties over a range of dynamic pressures. An adaptive wing provides a method for active aeroelastic tailoring of structural response to meet changing structural performance requirements during a roll maneuver.

8. STATIC TEST TOWER NORTHWEST ELEVATION FROM THE POWER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. STATIC TEST TOWER - NORTHWEST ELEVATION FROM THE POWER PLANT TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Correcting for static shift of magnetotelluric data with airborne electromagnetic measurements: a case study from Rathlin Basin, Northern Ireland

NASA Astrophysics Data System (ADS)

Delhaye, Robert; Rath, Volker; Jones, Alan G.; Muller, Mark R.; Reay, Derek

2017-05-01

Galvanic distortions of magnetotelluric (MT) data, such as the static-shift effect, are a known problem that can lead to incorrect estimation of resistivities and erroneous modelling of geometries with resulting misinterpretation of subsurface electrical resistivity structure. A wide variety of approaches have been proposed to account for these galvanic distortions, some depending on the target area, with varying degrees of success. The natural laboratory for our study is a hydraulically permeable volume of conductive sediment at depth, the internal resistivity structure of which can be used to estimate reservoir viability for geothermal purposes; however, static-shift correction is required in order to ensure robust and precise modelling accuracy.We present here a possible method to employ frequency-domain electromagnetic data in order to correct static-shift effects, illustrated by a case study from Northern Ireland. In our survey area, airborne frequency domain electromagnetic (FDEM) data are regionally available with high spatial density. The spatial distributions of the derived static-shift corrections are analysed and applied to the uncorrected MT data prior to inversion. Two comparative inversion models are derived, one with and one without static-shift corrections, with instructive results. As expected from the one-dimensional analogy of static-shift correction, at shallow model depths, where the structure is controlled by a single local MT site, the correction of static-shift effects leads to vertical scaling of resistivity-thickness products in the model, with the corrected model showing improved correlation to existing borehole wireline resistivity data. In turn, as these vertical scalings are effectively independent of adjacent sites, lateral resistivity distributions are also affected, with up to half a decade of resistivity variation between the models estimated at depths down to 2000 m. Simple estimation of differences in bulk porosity, derived using Archie's Law, between the two models reinforces our conclusion that the suborder of magnitude resistivity contrasts induced by the correction of static shifts correspond to similar contrasts in estimated porosities, and hence, for purposes of reservoir investigation or similar cases requiring accurate absolute resistivity estimates, galvanic distortion correction, especially static-shift correction, is essential.

CP-25 attenuates the inflammatory response of fibroblast-like synoviocytes co-cultured with BAFF-activated CD4(+) T cells.

PubMed

Jia, Xiaoyi; Wei, Fang; Sun, Xiaojing; Chang, Yan; Xu, Shu; Yang, Xuezhi; Wang, Chun; Wei, Wei

2016-08-02

Total glucosides of paeony (TGP) is the first anti-inflammatory immune regulatory drug approved for the treatment of rheumatoid arthritis in China. A novel compound, paeoniflorin-6'-O-benzene sulfonate (code CP-25), comes from the structural modification of paeoniflorin (Pae), which is the effective active ingredient of TGP. The aim of the present study is to investigate the effect of CP-25 on adjuvant arthritis (AA) fibroblast-like synoviocytes (FLS) co-cultured with BAFF-activated CD4(+) T cells and the expression of BAFF-R in CD4(+) T cells. The mRNA expression of BAFF and its receptors was assessed by qPCR. The expression of BAFF receptors in CD4(+) T cells was analyzed by flow cytometry. The effect of CP-25 on AA rats was evaluated by their joint histopathology. The cell culture growth of thymocytes and FLS was detected by cell counting kit (CCK-8). The concentrations of IL-1β, TNF-α, and IL-6 were measured by Enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of BAFF and BAFF-R were enhanced in the mesenteric lymph nodes of AA rats, TACI expression was reduced, and BCMA had no change. The expression of BAFF-R in CD4(+) T cells was also enhanced. CP-25 alleviated the joint histopathology and decreased the expression of BAFF-R in CD4(+) T cells from AA rats in vivo. In vitro, CP-25 inhibited the abnormal cell culture growth of BAFF-stimulated thymocytes and FLS. In the co-culture system, IL-1β, IL-6 and TNF-α production was enhanced by FLS co-cultured with BAFF-activated CD4(+) T cells. Moreover, BAFF-stimulated CD4(+) T cells promoted the cell culture growth of FLS. The addition of CP-25 decreased the expression of BAFF-R in CD4(+) T cells and inhibited the cell culture growth and cytokine secretion ability of FLS co-cultured with BAFF-activated CD4(+) T cells. The present study indicates that CP-25 may repress the cell culture growth and cytokine secretion ability of FLS, and its inhibitory effects might be associated with its ability to inhibit the expression of BAFF-R in CD4(+) T cells in a co-culture. These observations might provide a scientific basis for the development of new drugs for the treatment of autoimmune diseases by CP-25. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Performance tradeoffs in static and dynamic load balancing strategies

NASA Technical Reports Server (NTRS)

Iqbal, M. A.; Saltz, J. H.; Bokhart, S. H.

1986-01-01

The problem of uniformly distributing the load of a parallel program over a multiprocessor system was considered. A program was analyzed whose structure permits the computation of the optimal static solution. Then four strategies for load balancing were described and their performance compared. The strategies are: (1) the optimal static assignment algorithm which is guaranteed to yield the best static solution, (2) the static binary dissection method which is very fast but sub-optimal, (3) the greedy algorithm, a static fully polynomial time approximation scheme, which estimates the optimal solution to arbitrary accuracy, and (4) the predictive dynamic load balancing heuristic which uses information on the precedence relationships within the program and outperforms any of the static methods. It is also shown that the overhead incurred by the dynamic heuristic is reduced considerably if it is started off with a static assignment provided by either of the other three strategies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darling, Jeremy, E-mail: jdarling@colorado.edu

Objects and structures gravitationally decoupled from the Hubble expansion will appear to shrink in angular size as the universe expands. Observations of extragalactic proper motions can thus directly reveal the cosmic expansion. Relatively static structures such as galaxies or galaxy clusters can potentially be used to measure the Hubble constant, and test masses in large scale structures can measure the overdensity. Since recession velocities and angular separations can be precisely measured, apparent proper motions can also provide geometric distance measurements to static structures. The apparent fractional angular compression of static objects is 15 μas yr{sup –1} in the local universe;more » this motion is modulated by the overdensity in dynamic expansion-decoupled structures. We use the Titov et al. quasar proper motion catalog to examine the pairwise proper motion of a sparse network of test masses. Small-separation pairs (<200 Mpc comoving) are too few to measure the expected effect, yielding an inconclusive 8.3 ± 14.9 μas yr{sup –1}. Large-separation pairs (200-1500 Mpc) show no net convergence or divergence for z < 1, –2.7 ± 3.7 μas yr{sup –1}, consistent with pure Hubble expansion and significantly inconsistent with static structures, as expected. For all pairs a 'null test' gives –0.36 ± 0.62 μas yr{sup –1}, consistent with Hubble expansion and excludes a static locus at ∼5-10σ significance for z ≅ 0.5-2.0. The observed large-separation pairs provide a reference frame for small-separation pairs that will significantly deviate from the Hubble flow. The current limitation is the number of small-separation objects with precise astrometry, but Gaia will address this and will likely detect the cosmic recession.« less

Magnets for Pain Relief

MedlinePlus

... NCCIH NCCIH At a Glance Mission and Vision Organizational Structure ... been studied for pain. Static or permanent magnets : Static magnets have magnetic fields that do not change. The activity of electrons in the metal causes ...

Structural Finite Element Model Updating Using Vibration Tests and Modal Analysis for NPL footbridge - SHM demonstrator

NASA Astrophysics Data System (ADS)

Barton, E.; Middleton, C.; Koo, K.; Crocker, L.; Brownjohn, J.

2011-07-01

This paper presents the results from collaboration between the National Physical Laboratory (NPL) and the University of Sheffield on an ongoing research project at NPL. A 50 year old reinforced concrete footbridge has been converted to a full scale structural health monitoring (SHM) demonstrator. The structure is monitored using a variety of techniques; however, interrelating results and converting data to knowledge are not possible without a reliable numerical model. During the first stage of the project, the work concentrated on static loading and an FE model of the undamaged bridge was created, and updated, under specified static loading and temperature conditions. This model was found to accurately represent the response under static loading and it was used to identify locations for sensor installation. The next stage involves the evaluation of repair/strengthening patches under both static and dynamic loading. Therefore, before deliberately introducing significant damage, the first set of dynamic tests was conducted and modal properties were estimated. The measured modal properties did not match the modal analysis from the statically updated FE model; it was clear that the existing model required updating. This paper introduces the results of the dynamic testing and model updating. It is shown that the structure exhibits large non-linear, amplitude dependant characteristics. This creates a difficult updating process, but we attempt to produce the best linear representation of the structure. A sensitivity analysis is performed to determine the most sensitive locations for planned damage/repair scenarios and is used to decide whether additional sensors will be necessary.

Local time dependence of the thermal structure in the Venusian equatorial region revealed by Akatsuki radio occultation measurements

NASA Astrophysics Data System (ADS)

Ando, H.; Fukuhara, T.; Takagi, M.; Imamura, T.; Sugimoto, N.; Sagawa, H.

2017-12-01

The radio occultation technique is one of the most useful methods to retrieve vertical temperature profiles in planetary atmospheres. Ultra-Stable Oscillator (USO) onboard Venus Climate Orbiter, Akatsuki, enables us to investigate the thermal structure of the Venus atmosphere between about 40-90 km levels. It is expected that 35 temperature profiles will be obtained by the radio occultation measurements of Akatsuki until August 2017. Static stability derived from the temperature profiles shows its local time dependence above the cloud top level at low-latitudes equatorward of 25˚. The vertical profiles of the static stability in the dawn and dusk regions have maxima at 77 km and 82 km levels, respectively. A general circulation model (GCM) for the Venus atmosphere (AFES-Venus) reproduced the thermal structures above the cloud top qualitatively consistent with the radio occultation measurements; the maxima of the static stability are seen both in the dawn and dusk regions, and the local maximum of the static stability in the dusk region is located at a highler level than in the dawn region. Comparing the thermal structures between the radio occultation measurements and the GCM results, it is suggested that the distribution of the static stability above the cloud top could be strongly affected by the diurnal tide. The thermal tide influences on the thermal structure as well as atmospheric motions above the cloud level. In addition, it is shown that zonally averaged zonal wind at about 80 km altitude could be roughly estimated from the radio occultation measurements using the dispersion relation of the internal gravity wave.

Deformation effect simulation and optimization for double front axle steering mechanism

NASA Astrophysics Data System (ADS)

Wu, Jungang; Zhang, Siqin; Yang, Qinglong

2013-03-01

This paper research on tire wear problem of heavy vehicles with Double Front Axle Steering Mechanism from the flexible effect of Steering Mechanism, and proposes a structural optimization method which use both traditional static structural theory and dynamic structure theory - Equivalent Static Load (ESL) method to optimize key parts. The good simulated and test results show this method has high engineering practice and reference value for tire wear problem of Double Front Axle Steering Mechanism design.

Static and Dynamical Structural Investigations of Metal-Oxide Nanocrystals by Powder X-ray Diffraction: Colloidal Tungsten Oxide as a Case Study

DOE PAGES

Caliandro, Rocco; Sibillano, Teresa; Belviso, B. Danilo; ...

2016-02-02

In this study, we have developed a general X-ray powder diffraction (XPD) methodology for the simultaneous structural and compositional characterization of inorganic nanomaterials. The approach is validated on colloidal tungsten oxide nanocrystals (WO 3-x NCs), as a model polymorphic nanoscale material system. Rod-shaped WO 3-x NCs with different crystal structure and stoichiometry are comparatively investigated under an inert atmosphere and after prolonged air exposure. An initial structural model for the as-synthesized NCs is preliminarily identified by means of Rietveld analysis against several reference crystal phases, followed by atomic pair distribution function (PDF) refinement of the best-matching candidates (static analysis). Subtlemore » stoichiometry deviations from the corresponding bulk standards are revealed. NCs exposed to air at room temperature are monitored by XPD measurements at scheduled time intervals. The static PDF analysis is complemented with an investigation into the evolution of the WO 3-x NC structure, performed by applying the modulation enhanced diffraction technique to the whole time series of XPD profiles (dynamical analysis). Prolonged contact with ambient air is found to cause an appreciable increase in the static disorder of the O atoms in the WO 3-x NC lattice, rather than a variation in stoichiometry. Finally, the time behavior of such structural change is identified on the basis of multivariate analysis.« less

Improved fatigue performance for wood-based structural panels using slot and tab construction

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2016-01-01

This paper presents static and fatigue bending behavior for a wood-based structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated panels without the S/T construction technique. Experimental results showed that both types of panels had similar bending properties in the static tests. However, the panels with S/T...

Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belov, Nikolay, E-mail: n.n.belov@mail.ru; Kopanitsa, Dmitry, E-mail: kopanitsa@mail.ru; Yugov, Alexey, E-mail: yugalex@mail.ru

When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved usingmore » software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.« less

18. STATIC TEST TOWER VIEW FROM REMOVABLE LEVEL DOWN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. STATIC TEST TOWER - VIEW FROM REMOVABLE LEVEL DOWN TOWARDS GANTRY CRANE AND THREE TEST CELLS. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Sawja: Static Analysis Workshop for Java

NASA Astrophysics Data System (ADS)

Hubert, Laurent; Barré, Nicolas; Besson, Frédéric; Demange, Delphine; Jensen, Thomas; Monfort, Vincent; Pichardie, David; Turpin, Tiphaine

Static analysis is a powerful technique for automatic verification of programs but raises major engineering challenges when developing a full-fledged analyzer for a realistic language such as Java. Efficiency and precision of such a tool rely partly on low level components which only depend on the syntactic structure of the language and therefore should not be redesigned for each implementation of a new static analysis. This paper describes the Sawja library: a static analysis workshop fully compliant with Java 6 which provides OCaml modules for efficiently manipulating Java bytecode programs. We present the main features of the library, including i) efficient functional data-structures for representing a program with implicit sharing and lazy parsing, ii) an intermediate stack-less representation, and iii) fast computation and manipulation of complete programs. We provide experimental evaluations of the different features with respect to time, memory and precision.

Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head

PubMed Central

Li, Jinghao; Hunt, John F; Gong, Shaoqin; Cai, Zhiyong

2017-01-01

This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite structural panels using a spherical load head. Panels were made having different core and face configurations. The results showed that panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial structural core; the core with a smaller structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite structural panels for potential impact applications. PMID:28772542

Control Augmented Structural Synthesis

NASA Technical Reports Server (NTRS)

Lust, Robert V.; Schmit, Lucien A.

1988-01-01

A methodology for control augmented structural synthesis is proposed for a class of structures which can be modeled as an assemblage of frame and/or truss elements. It is assumed that both the plant (structure) and the active control system dynamics can be adequately represented with a linear model. The structural sizing variables, active control system feedback gains and nonstructural lumped masses are treated simultaneously as independent design variables. Design constraints are imposed on static and dynamic displacements, static stresses, actuator forces and natural frequencies to ensure acceptable system behavior. Multiple static and dynamic loading conditions are considered. Side constraints imposed on the design variables protect against the generation of unrealizable designs. While the proposed approach is fundamentally more general, here the methodology is developed and demonstrated for the case where: (1) the dynamic loading is harmonic and thus the steady state response is of primary interest; (2) direct output feedback is used for the control system model; and (3) the actuators and sensors are collocated.

Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

NASA Astrophysics Data System (ADS)

Schilder, Constanze; Kohlhoff, Harald; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang R.; Baeßler, Matthias; Niederleithinger, Ernst; Georgi, Steven; Herten, Markus

2013-05-01

Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load tests and pile integrity tests.

29. SATURN ROCKET ENGINE LOCATED ON NORTH SIDE OF STATIC ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. SATURN ROCKET ENGINE LOCATED ON NORTH SIDE OF STATIC TEST STAND - DETAILS OF THE EXPANSION NOZZLE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

22. STATIC TEST TOWER VIEW OF TEST CELLS AND F1 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. STATIC TEST TOWER VIEW OF TEST CELLS AND F-1 TEST LOCK DOWN FOR ENGINE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Operating System Support for Shared Hardware Data Structures

DTIC Science & Technology

2013-01-31

Carbon [73] uses hardware queues to improve fine-grained multitasking for Recognition, Mining , and Synthesis. Compared to software ap- proaches...web transaction processing, data mining , and multimedia. Early work in database processors [114, 96, 79, 111] reduce the costs of relational database...assignment can be solved statically or dynamically. Static assignment deter- mines offline which data structures are assigned to use HWDS resources and at

The Seismic Design of Waterfront Retaining Structures

DTIC Science & Technology

1993-01-01

of elastic backfill behind a rigid wall .... .......... .. 134 5.2 Pressure distributions on smooth rigid wall for l-g static horizontal body force...135 5.3 Resultant force and resultant moment on smooth rigid wall for l-g static horizontal body force...distributions on smooth rigid wall for 1-g static horizontal body force clearly showed the limitations of Woods simplified procedure when this condi- tion is not

Static Aeroelastic and Longitudinal Trim Model of Flexible Wing Aircraft Using Finite-Element Vortex-Lattice Coupled Solution

NASA Technical Reports Server (NTRS)

Ting, Eric; Nguyen, Nhan; Trinh, Khanh

2014-01-01

This paper presents a static aeroelastic model and longitudinal trim model for the analysis of a flexible wing transport aircraft. The static aeroelastic model is built using a structural model based on finite-element modeling and coupled to an aerodynamic model that uses vortex-lattice solution. An automatic geometry generation tool is used to close the loop between the structural and aerodynamic models. The aeroelastic model is extended for the development of a three degree-of-freedom longitudinal trim model for an aircraft with flexible wings. The resulting flexible aircraft longitudinal trim model is used to simultaneously compute the static aeroelastic shape for the aircraft model and the longitudinal state inputs to maintain an aircraft trim state. The framework is applied to an aircraft model based on the NASA Generic Transport Model (GTM) with wing structures allowed to flexibly deformed referred to as the Elastically Shaped Aircraft Concept (ESAC). The ESAC wing mass and stiffness properties are based on a baseline "stiff" values representative of current generation transport aircraft.

Microrheology: Structural evolution under static and dynamic conditions by simultaneous analysis of confocal microscopy and diffusing wave spectroscopy

NASA Astrophysics Data System (ADS)

Nicolas, Yves; Paques, Marcel; Knaebel, Alexandra; Steyer, Alain; Munch, Jean-Pierre; Blijdenstein, Theo B. J.; van Aken, George A.

2003-08-01

An oscillatory shear configuration was developed to improve understanding of structural evolution during deformation. It combines an inverted confocal scanning laser microscope (CSLM) and a special sample holder that can apply to the sample specific deformation: oscillatory shear or steady strain. In this configuration, a zero-velocity plane is created in the sample by moving two plates in opposite directions, thereby providing stable observation conditions of the structural behavior under deformation. The configuration also includes diffusion wave spectroscopy (DWS) to monitor the network properties via particle mobility under static and dynamic conditions. CSLM and DWS can be performed simultaneously and three-dimensional images can be obtained under static conditions. This configuration is mainly used to study mechanistic phenomena like particle interaction, aggregation, gelation and network disintegration, interactions at interfaces under static and dynamic conditions in semisolid food materials (desserts, dressings, sauces, dairy products) and in nonfood materials (mineral emulsions, etc.). Preliminary data obtained with this new oscillatory shear configuration are described that demonstrate their capabilities and the potential contribution to other areas of application also.

Structural Testing of a 6m Hypersonic Inflatable Aerodynamic Decelerator System

NASA Technical Reports Server (NTRS)

Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.

2015-01-01

NASA is developing low ballistic coefficient technologies to support the Nations long-term goal of landing humans on Mars. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current and future launch vehicle fairing limitations. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) are being developed to circumvent this limitation and are now considered a leading technology to enable landing of heavy payloads on Mars. At the beginning of 2014, a 6m diameter HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify its structural performance under flight-relevant loads. The inflatable structure was constructed into a 60 degree sphere-cone configuration using nine inflatable torus segments composed of fiber-reinforced thin films. The inflatable tori were joined together using adhesives and high-strength textile woven structural straps. These straps help distribute the load throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials that are designed to protect the inflatable structure from heat loads that would be seen in flight during atmospheric entry. A custom test fixture was constructed to perform the static load test series. The fixture consisted of a round structural tub with enough height and width to allow for displacement of the HIAD test article as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The rigid centerbody of the HIAD was mounted to a pedestal in the center of the structural tub. Using an impermeable membrane draped over the HIAD test article, an airtight seal was created with the top rim of the static load tub. This seal allowed partial vacuum to be pulled beneath the HIAD resulting in a uniform static pressure load applied to the outer surface. Using this technique, the test article was subjected to loads of up to 50,000lbs. During the test series an extensive amount of instrumentation was used to provide a rich data set, including deflected shape, structural strap loads, torus cord loads, inflation pressures, and applied static load. In this paper the 2014 6m HIAD static load test series will be discussed in detail, including the design of the 6m HIAD test article, the test setup, and test execution. Analysis results will be described supporting the conclusions that were drawn from the test series..

Overview of the 2nd Gen 3.7m HIAD Static Load Test

NASA Technical Reports Server (NTRS)

Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.; Cheatwood, F. M.; Cassell, A. M.; Anderson, P.; Lowery, A.

2015-01-01

To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for human class payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). In October of 2014, a 3.7m HIAD inflatable structure with an integrated flexible thermal protection sys-tem (F-TPS) was subjected to a static load test series to verify the designs structural performance. The 3.7m HIAD structure was constructed in a 70 deg sphere-cone stacked-toroid configuration using eight inflatable tori, which were joined together using adhesives and high strength textile webbing to help distribute the loads throughout the inflatable structure. The inflatable structure was fabricated using 2nd generation structural materials that permit an increase in use temperature to 400 C+ as compared to the 250 C limitation of the 1st generation materials. In addition to the temperature benefit, these materials also offer a 40 reduction in structure mass. The 3.7m F-TPS was fabricated using high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. The F-TPS was constructed of 2nd generation TPS materials increasing its heating capability from 35W sq cm to over 100W sq cm. This test article is the first stacked-torus HIAD to be fabricated and tested with a 70 deg sphere-cone. All previous stacked-torus HIADs have employed a 60o sphere-cone. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for dis-placement of the inflatable structure as loads were applied. The tub rim was attached to the floor to provide an airtight seal. The center body of the inflatable structure was attached to a pedestal mount as seen in Figure 1. Using an impermeable membrane seal draped over the test article, partial vacuum was pulled beneath the HIAD, resulting in a uniform static pressure load applied to the outer surface. During the test series an extensive amount of instrumentation was used to characterize deformed shape, shoulder deflection, strap loads, and cord loads as a function of structural configuration and applied static load. In this overview, the 3.7m HIAD static load test series will be discussed in detail, including the 3.7m HIAD inflatable structure and flexible TPS design, test setup and execution, and finally results and conclusions from the test series.

Static Structural Analysis of a Variable Span Morphing Wing for Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Bashir, M.; Rajendran, P.

2018-05-01

While the primary reason to develop an adaptive wing is the aerodynamic benefits, the primary hindrance is the structural and vibrational considerations due to the unsteady nature of the airflow during the flight. Hence this study forms an important part of the morphable wing technology. In this paper, the design of a moderate aspect ratio variable span wing will be performed. The morphing wing is modeled structurally to observe the effect of spanwise load distribution on the wing structure. For the structural design and analysis of the unmanned aerial vehicle (UAV) under this study, commercial software Solidworks and Ansys/Static Structural/Modal are used. The static structural analyses of the wing are performed under different load conditions. The results of these analyses show that the designed structure is safe within the flight envelope. It is observed that the wing-root bending moment increases drastically due to an increase in the wingspan. Thus, the bending moment along the wingspan of the morphing wing is much larger than that of the conventional wing which results in an increase in the deflection of the free-end. The maximum stress for the un-extended wing configuration increases for the extended wing configuration.

Photogrammetry and Videogrammetry Methods for Solar Sails and Other Gossamer Structures

NASA Technical Reports Server (NTRS)

Black, Jonathan T.; Pappa, Richard S.

2004-01-01

Ultra-lightweight and inflatable gossamer space structures are designed to be tightly packaged for launch, then deploy or inflate once in space. These properties will allow for in-space construction of very large structures 10 to 1000 meters in size such as solar sails, inflatable antennae, and space solar power stations using a single launch. Solar sails are of particular interest because of their potential for propellantless propulsion. Gossamer structures do, however, have significant complications. Their low mass and high flexibility make them very difficult to test on the ground. The added mass and stiffness of attached measurement devices can significantly alter the static and dynamic properties of the structure. This complication necessitates an alternative approach for characterization. This paper discusses the development and application of photogrammetry and videogrammetry methods for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, noncontact, dynamic characterization using dot projection videogrammetry.

20. UNCOVERED TEST CELL AT THE STATIC TEST TOWER ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. UNCOVERED TEST CELL AT THE STATIC TEST TOWER ON THE WEST SIDE WHERE F-1 ENGINE WAS TESTED. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Asymmetric ratchet effect for directional transport of fog drops on static and dynamic butterfly wings.

PubMed

Liu, Chengcheng; Ju, Jie; Zheng, Yongmei; Jiang, Lei

2014-02-25

Inspired by novel creatures, researchers have developed varieties of fog drop transport systems and made significant contributions to the fields of heat transferring, water collecting, antifogging, and so on. Up to now, most of the efforts in directional fog drop transport have been focused on static surfaces. Considering it is not practical to keep surfaces still all the time in reality, conducting investigations on surfaces that can transport fog drops in both static and dynamic states has become more and more important. Here we report the wings of Morpho deidamia butterflies can directionally transport fog drops in both static and dynamic states. This directional drop transport ability results from the micro/nano ratchet-like structure of butterfly wings: the surface of butterfly wings is composed of overlapped scales, and the scales are covered with porous asymmetric ridges. Influenced by this special structure, fog drops on static wings are transported directionally as a result of the fog drops' asymmetric growth and coalescence. Fog drops on vibrating wings are propelled directionally due to the fog drops' asymmetric dewetting from the wings.

Damage Instability and Transition From Quasi-Static to Dynamic Fracture

NASA Technical Reports Server (NTRS)

Davila, Carlos G.

2015-01-01

In a typical mechanical test, the loading phase is intended to be a quasi-static process, while the failure and collapse is usually a dynamic event. The structural strength and modes of damage can seldom be predicted without accounting for these two aspects of the response. For a proper prediction, it is therefore essential to use tools and methodologies that are capable of addressing both aspects of responses. In some cases, implicit quasi-static models have been shown to be able to predict the entire response of a structure, including the unstable path that leads to fracture. However, is it acceptable to ignore the effect of inertial forces in the formation of damage? In this presentation we examine aspects of the damage processes that must be simulated for an accurate prediction of structural strength and modes of failure.

Correlation between temperature variations of static and dynamic properties in glass-forming liquids

DOE PAGES

Voylov, D. N.; Griffin, P. J.; Mercado, B.; ...

2016-12-29

In this detailed analysis of the static structure factor S(Q) in several glass-forming liquids we show that the temperature variations of the width of the main diffraction peak Q(T ) correlate with the fragility of these liquids. Our observation suggests a direct connection between rather subtle structural changes and sharp slowing down of structural relaxation in glass-forming liquids. We also show that this observation can be rationalized using the Adam-Gibbs approach, through a connection between temperature variations of structural correlation length, lc 2 /Q, and the size of cooperatively rearranging regions.

Effect of ion-beam treatment on structure and fracture resistance of 12Cr1MoV steel under static, cyclic and dynamic loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panin, S. V., E-mail: svp@ispms.tsc.ru; Vlasov, I. V., E-mail: good0@yandex.ru; Sergeev, V. P., E-mail: retc@ispms.tsc.ru

2015-10-27

Features of the structure and properties modification of 12Cr1MoV steel subjected to irradiation by zirconium ion beam have been investigated with the use of optical and electron microscopy as well as microhardness measurement. It has been shown that upon treatment the structure modification occurred across the entire cross-section of specimens with the thickness of 1 mm. Changes in the mechanical properties of these specimens under static, cyclic and impact loading are interpreted in terms of identified structure changes.

Static structure of active Brownian hard disks

NASA Astrophysics Data System (ADS)

de Macedo Biniossek, N.; Löwen, H.; Voigtmann, Th; Smallenburg, F.

2018-02-01

We explore the changes in static structure of a two-dimensional system of active Brownian particles (ABP) with hard-disk interactions, using event-driven Brownian dynamics simulations. In particular, the effect of the self-propulsion velocity and the rotational diffusivity on the orientationally-averaged fluid structure factor is discussed. Typically activity increases structural ordering and generates a structure factor peak at zero wave vector which is a precursor of motility-induced phase separation. Our results provide reference data to test future statistical theories for the fluid structure of active Brownian systems. This manuscript was submitted for the special issue of the Journal of Physics: Condensed Matter associated with the Liquid Matter Conference 2017.

Theory for solubility in static systems

NASA Astrophysics Data System (ADS)

Gusev, Andrei A.; Suter, Ulrich W.

1991-06-01

A theory for the solubility of small particles in static structures has been developed. The distribution function of the solute in a frozen solid has been derived in analytical form for the quantum and the quasiclassical cases. The solubility at infinitesimal gas pressure (Henry's constant) as well as the pressure dependence of the solute concentration at elevated pressures has been found from the statistical equilibrium between the solute in the static matrix and the ideal-gas phase. The distribution function of a solute containing different particles has been evaluated in closed form. An application of the theory to the sorption of methane in the computed structures of glassy polycarbonate has resulted in a satisfactory agreement with experimental data.

Structural features that predict real-value fluctuations of globular proteins.

PubMed

Jamroz, Michal; Kolinski, Andrzej; Kihara, Daisuke

2012-05-01

It is crucial to consider dynamics for understanding the biological function of proteins. We used a large number of molecular dynamics (MD) trajectories of nonhomologous proteins as references and examined static structural features of proteins that are most relevant to fluctuations. We examined correlation of individual structural features with fluctuations and further investigated effective combinations of features for predicting the real value of residue fluctuations using the support vector regression (SVR). It was found that some structural features have higher correlation than crystallographic B-factors with fluctuations observed in MD trajectories. Moreover, SVR that uses combinations of static structural features showed accurate prediction of fluctuations with an average Pearson's correlation coefficient of 0.669 and a root mean square error of 1.04 Å. This correlation coefficient is higher than the one observed in predictions by the Gaussian network model (GNM). An advantage of the developed method over the GNMs is that the former predicts the real value of fluctuation. The results help improve our understanding of relationships between protein structure and fluctuation. Furthermore, the developed method provides a convienient practial way to predict fluctuations of proteins using easily computed static structural features of proteins. Copyright © 2012 Wiley Periodicals, Inc.

Structural features that predict real-value fluctuations of globular proteins

PubMed Central

Jamroz, Michal; Kolinski, Andrzej; Kihara, Daisuke

2012-01-01

It is crucial to consider dynamics for understanding the biological function of proteins. We used a large number of molecular dynamics trajectories of non-homologous proteins as references and examined static structural features of proteins that are most relevant to fluctuations. We examined correlation of individual structural features with fluctuations and further investigated effective combinations of features for predicting the real-value of residue fluctuations using the support vector regression. It was found that some structural features have higher correlation than crystallographic B-factors with fluctuations observed in molecular dynamics trajectories. Moreover, support vector regression that uses combinations of static structural features showed accurate prediction of fluctuations with an average Pearson’s correlation coefficient of 0.669 and a root mean square error of 1.04 Å. This correlation coefficient is higher than the one observed for the prediction by the Gaussian network model. An advantage of the developed method over the Gaussian network models is that the former predicts the real-value of fluctuation. The results help improve our understanding of relationships between protein structure and fluctuation. Furthermore, the developed method provides a convienient practial way to predict fluctuations of proteins using easily computed static structural features of proteins. PMID:22328193

Anti-Arthritic Effects of Magnolol in Human Interleukin 1β-Stimulated Fibroblast-Like Synoviocytes and in a Rat Arthritis Model

PubMed Central

Wang, Jyh-Horng; Shih, Kao-Shang; Liou, Jing-Ping; Wu, Yi-Wen; Chang, Anita Shin-Yuan; Wang, Kang-Li; Tsai, Ching-Lin; Yang, Chia-Ron

2012-01-01

Fibroblast-like synoviocytes (FLS) play an important role in the pathologic processes of destructive arthritis by producing a number of catabolic cytokines and metalloproteinases (MMPs). The expression of these mediators is controlled at the transcriptional level. The purposes of this study were to evaluate the anti-arthritic effects of magnolol (5,5′-Diallyl-biphenyl-2,2′-diol), the major bioactive component of the bark of Magnolia officinalis, by examining its inhibitory effects on inflammatory mediator secretion and the NF-κB and AP-1 activation pathways and to investigate its therapeutic effects on the development of arthritis in a rat model. The in vitro anti-arthritic activity of magnolol was tested on interleukin (IL)-1β-stimulated FLS by measuring levels of IL-6, cyclooxygenase-2, prostaglandin E2, and matrix metalloproteinases (MMPs) by ELISA and RT-PCR. Further studies on how magnolol inhibits IL-1β-stimulated cytokine expression were performed using Western blots, reporter gene assay, electrophoretic mobility shift assay, and confocal microscope analysis. The in vivo anti-arthritic effects of magnolol were evaluated in a Mycobacterium butyricum-induced arthritis model in rats. Magnolol markedly inhibited IL-1β (10 ng/mL)-induced cytokine expression in a concentration-dependent manner (2.5–25 µg/mL). In clarifying the mechanisms involved, magnolol was found to inhibit the IL-1β-induced activation of the IKK/IκB/NF-κB and MAPKs pathways by suppressing the nuclear translocation and DNA binding activity of both transcription factors. In the animal model, magnolol (100 mg/kg) significantly inhibited paw swelling and reduced serum cytokine levels. Our results demonstrate that magnolol inhibits the development of arthritis, suggesting that it might provide a new therapeutic approach to inflammatory arthritis diseases. PMID:22359588

Regulatory effect of calcineurin inhibitor, tacrolimus, on IL-6/sIL-6R-mediated RANKL expression through JAK2-STAT3-SOCS3 signaling pathway in fibroblast-like synoviocytes

PubMed Central

2013-01-01

Introduction This study investigated whether the calcineurin inhibitor, tacrolimus, suppresses receptor activator of NF-κB ligand (RANKL) expression in fibroblast-like synoviocytes (FLS) through regulation of IL-6/Janus activated kinase (JAK2)/signal transducer and activator of transcription-3 (STAT3) and suppressor of cytokine signaling (SOCS3) signaling. Methods The expression of RANKL, JAK2, STAT3, and SOCS3 proteins was assessed by western blot analysis, real-time PCR and ELISA in IL-6 combined with soluble IL-6 receptor (sIL-6R)-stimulated rheumatoid arthritis (RA)-FLS with or without tacrolimus treatment. The effects of tacrolimus on synovial inflammation and bone erosion were assessed using mice with arthritis induced by K/BxN serum. Immunofluorescent staining was performed to identify the effect of tacrolimus on RANKL and SOCS3. The tartrate-resistant acid phosphatase staining assay was performed to assess the effect of tacrolimus on osteoclast differentiation. Results We found that RANKL expression in RA FLS is regulated by the IL-6/sIL-6R/JAK2/STAT3/SOCS3 pathway. Inhibitory effects of tacrolimus on RANKL expression in a serum-induced arthritis mice model were identified. Tacrolimus inhibits RANKL expression in IL-6/sIL-6R-stimulated FLS by suppressing STAT3. Among negative regulators of the JAK/STAT pathway, such as CIS1, SOCS1, and SOCS3, only SOCS3 is significantly induced by tacrolimus. As compared to dexamethasone and methotrexate, tacrolimus more potently suppresses RANKL expression in FLS. By up-regulating SOCS3, tacrolimus down-regulates activation of the JAK-STAT pathway by IL-6/sIL-6R trans-signaling, thus decreasing RANKL expression in FLS. Conclusions These data suggest that tacrolimus might affect the RANKL expression in IL-6 stimulated FLS through STAT3 suppression, together with up-regulation of SOCS3. PMID:23406906

Transcription Factor SOX5 Promotes the Migration and Invasion of Fibroblast-Like Synoviocytes in Part by Regulating MMP-9 Expression in Collagen-Induced Arthritis.

PubMed

Shi, Yumeng; Wu, Qin; Xuan, Wenhua; Feng, Xiaoke; Wang, Fang; Tsao, Betty P; Zhang, Miaojia; Tan, Wenfeng

2018-01-01

Fibroblast-like synoviocytes (FLS) exhibit a unique aggressive phenotype in rheumatoid arthritis (RA). Increased FLS migration and subsequent invasion of the extracellular matrix are essential to joint destruction in RA. Our previous research reported that transcription factor SOX5 was highly expressed in RA-FLS. Here, the effects of SOX5 in RA-FLS migration and invasion will be investigated. The migration and invasion of RA-FLS were evaluated using a transwell chamber assay. The expression of several potential SOX5-targeted genes, including matrix metalloproteinases (MMP-1, 2, 3 and 9), chemokines (CCL4, CCL2, CCR5 and CCR2), and pro-inflammatory cytokines (TNF-α and IL-6), were examined in RA-FLS using SOX5 gain- and loss-of-function study. The molecular mechanisms of SOX5-mediated MMP-9 expressions were assayed by luciferase reporter gene and chromatin immunoprecipitation (ChIP) studies. The in vivo effect of SOX5 on FLS migration and invasion was examined using collagen-induced arthritis (CIA) in DBA/1J mice. Knockdown SOX5 decreased lamellipodium formation, migration, and invasion of RA-FLS. The expression of MMP-9 was the only gene tested to be concomitantly affected by silencing or overexpressing SOX5. ChIP assay revealed that SOX5 was bound to the MMP-9 promoter in RA-FLS. The overexpression of SOX5 markedly enhanced the MMP-9 promoter activity, and specific deletion of a putative SOX5-binding site in MMP-9 promoter diminished this promoter-driven transcription in FLS. Locally knocked down SOX5 inhibited MMP-9 expression in the joint tissue and reduced pannus migration and invasion into the cartilage in CIA mice. SOX5 plays a novel role in mediating migration and invasion of FLS in part by regulating MMP-9 expression in RA.

Anti-inflammatory and apoptotic effects of the polyphenol curcumin on human fibroblast-like synoviocytes.

PubMed

Kloesch, Burkhard; Becker, Tatjana; Dietersdorfer, Elisabeth; Kiener, Hans; Steiner, Guenter

2013-02-01

It has recently been reported that the polyphenol curcumin has pronounced anti-carcinogenic, anti-inflammatory and pro-apoptotic properties. This study investigated possible anti-inflammatory and apoptotic effects of curcumin on the human synovial fibroblast cell line MH7A, and on fibroblast-like synoviocytes (FLS) derived from patients with rheumatoid arthritis (RA). MH7A cells and RA-FLS were stimulated either with interleukin (IL)-1β or phorbol 12-myristate 13 acetate (PMA), and treated simultaneously or sequentially with increasing concentrations of curcumin. Release of interleukin (IL)-6 and vascular endothelial growth factor (VEGF)-A was quantified by enzyme-linked immunosorbent assays (ELISAs). In MH7A cells, modulation of the transcription factor nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinases (MAPKs) such as p38 and extracellular-signal regulated kinase (ERK1/2) were analysed by a reporter gene assay and Western blot, respectively. Pro-apoptotic events were monitored by Annexin-V/7-AAD based assay. Cleavage of pro-caspase-3 and -7 was checked with specific antibodies. Curcumin effectively blocked IL-1β and PMA-induced IL-6 expression both in MH7A cells and RA-FLS. VEGF-A expression could only be detected in RA-FLS and was induced by PMA, but not by IL-1β. Furthermore, curcumin inhibited activation of NF-κB and induced dephosphorylation of ERK1/2. Treatment of FLS with high concentrations of curcumin was associated with a decrease in cell viability and induction of apoptosis. The natural compound curcumin represents strong anti-inflammatory properties and induces apoptosis in FLS. This study provides an insight into possible molecular mechanisms of this substance and suggests it as a natural remedy for the treatment of chronic inflammatory diseases like RA. Copyright © 2013 Elsevier B.V. All rights reserved.

Inhibition of NF-κB pathway in fibroblast-like synoviocytes by α-mangostin implicated in protective effects on joints in rats suffering from adjuvant-induced arthritis.

PubMed

Zuo, Jian; Yin, Qin; Wang, Yu-Wei; Li, Yan; Lu, Lin-Ming; Xiao, Zhan-Gang; Wang, Guo-Dong; Luan, Jia-Jie

2018-03-01

α-Mangostin (MG) is a bioactive compound isolated from mangosteen. This study was aimed to investigate effects of MG on adjuvant-induced arthritis (AA) in rats and decipher the underlying mechanisms. Clinical severity of AA was evaluated by paw oedema, arthritis score, and hematological parameters. Digital radiography (DR) and histological examinations were employed to assess joints destructions. Immune functions were evaluated by T cell subsets distribution. Effects on NF-κB pathway were investigated by immunohistochemical, western-blot and immunofluorescence methods both in vivo and vitro. It was found MG possessed superior anti-inflammatory effects in vivo, suggested by attenuated paw swelling, reduced inflammatory cells infiltration and decreased the secretion of TNF-α and IL-1β in serum. Meanwhile MG inhibited fibrous hyperplasia, synovial angiogenesis, cartilage and bone degradation in AA rats. Although MG exerted little effects on CD4 + population, it greatly decreased IFN-γ positive cells and promoted expression of FOXP3 in immune organs, indicating restoration of Th1/Treg cells ratio and recovery of immune homeostasis in vivo. Inhibition of NF-κB induced by MG was indicated by reduced the expression of p-p65 and VEGF in synovium. In vitro experiments found MG at 10 μg/ml significantly suppressed the expression and phosphorylation of key proteins implicated in NF-κB pathway and inhibited nucleus translocation of p65. These changes led to increased apoptosis and proliferation inhibition of HFLS-RA cells. The results demonstrated regulation of immune functions was deeply involved in the therapeutic actions of MG on AA, and it's inhibition on NF-κB in fibroblast-like synoviocytes was associated to the protective effects on joints. Copyright © 2018 Elsevier B.V. All rights reserved.

Oxygen and indocyanine green loaded phase-transition nanoparticle-mediated photo-sonodynamic cytotoxic effects on rheumatoid arthritis fibroblast-like synoviocytes.

PubMed

Tang, Qin; Cui, Jianyu; Tian, Zhonghua; Sun, Jiangchuan; Wang, Zhigang; Chang, Shufang; Zhu, Shenyin

2017-01-01

Photodynamic therapy and sonodynamic therapy are developing, minimally invasive, and site-specific modalities for cancer therapy. A combined strategy PSDT (photodynamic therapy followed by sonodynamic therapy) has been proposed in this study. Here, we aimed to develop novel biodegradable poly(DL-lactide- co -glycolic acid) phase-transition nanoparticles simultaneously loaded with oxygen and indocyanine green (OI-NPs) and to investigate the cytotoxic effects and the potential mechanisms of OI-NP-mediated PSDT on MH7A synoviocytes. The OI-NPs were prepared using a modified double emulsion method and the physicochemical properties were determined. The cellular uptake of OI-NPs was detected by confocal microscopy and flow cytometry. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay, flow cytometry, and Hoechst 33342/propidium iodide double staining were used to determine the cytotoxic effect of OI-NP-mediated PSDT on MH7A cells. Fluorescence microscope and fluorescence microplate reader were used to detect reactive oxygen species (ROS) generation. The OI-NPs were a stable and efficient carrier to deliver oxygen and indocyanine green, and enhanced cellular uptake was observed in MH7A cells with the nanoparticles. OI-NP-mediated PSDT caused more serious cell damage and more evident cell apoptosis, compared with other groups. Furthermore, increased generation of intracellular ROS was detected in MH7A cells treated with PSDT. Interestingly, the OI-NP-mediated PSDT-induced cell viability loss was effectively rescued by pretreatment with the ROS scavenger N -acetylcysteine. Multifunctional OI-NPs were successfully developed and characterized for the combined delivery of oxygen and indocyanine green, and OI-NP-mediated PSDT would be a potential cytotoxic treatment for MH7A cells. This study may provide a novel strategy for the treatment of RA and develop a model of theranostic application through phase-transition nanoparticle-mediated PSDT in the future.

Cyr61 induces IL-6 production by fibroblast-like synoviocytes promoting Th17 differentiation in rheumatoid arthritis.

PubMed

Lin, Jinpiao; Zhou, Zhou; Huo, Rongfen; Xiao, Lianbo; Ouyang, Guilin; Wang, Li; Sun, Yue; Shen, Baihua; Li, Dangsheng; Li, Ningli

2012-06-01

Cysteine-rich protein 61 (Cyr61)/CCN1 is a product of an immediate early gene and functions in mediating cell adhesion and inducing cell migration. We previously showed that increased production of Cyr61 by fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) promotes FLS proliferation and participates in RA pathogenesis with the IL-17-dependent pathway. However, whether Cyr61 in turn regulates Th17 cell differentiation and further enhances inflammation of RA remained unknown. In the current study, we explored the potential role of Cyr61 as a proinflammatory factor in RA pathogenesis. We found that Cyr61 treatment dramatically induced IL-6 production in FLS isolated from RA patients. Moreover, IL-6 production was attenuated by Cyr61 knockdown in FLS. Mechanistically, we showed that Cyr61 activated IL-6 production via the αvβ5/Akt/NF-κB signaling pathway. Further, using a coculture system consisting of purified CD4(+) T cells and RA FLS, we found that RA FLS stimulated Th17 differentiation, and the pro-Th17 differentiation effect of RA FLS can be attenuated or stimulated by Cyr61 RNA interference or addition of exogenous Cyr61, respectively. Finally, using the collagen-induced arthritis animal model, we showed that treatment with the anti-Cyr61 mAb led to reduction of IL-6 levels, decrease of Th17 response, and attenuation of inflammation and disease progression in vivo. Taken together, our results reveal a novel role of Cyr61 in promoting Th17 development in RA via upregulation of IL-6 production by FLS, thus adding a new layer into the functional interplay between FLS and Th17 in RA pathogenesis. Our study also suggests that targeting of Cyr61 may represent a novel strategy in RA treatment.

Invasiveness of fibroblast-like synoviocytes is an individual patient characteristic associated with the rate of joint destruction in patients with rheumatoid arthritis.

PubMed

Tolboom, Tanja C A; van der Helm-Van Mil, Annette H M; Nelissen, Rob G H H; Breedveld, Ferdinand C; Toes, René E M; Huizinga, Tom W J

2005-07-01

Rheumatoid arthritis (RA) is characterized by inflammation and destruction of synovial joints. Fibroblast-like synoviocytes (FLS) harvested from synovial tissue of patients with RA can invade normal human cartilage in severe combined immunodeficient (SCID) mice and Matrigel basement membrane matrix in vitro. This study was undertaken to investigate the association of these in vitro characteristics with disease characteristics in patients with RA. Synovial tissue samples from 72 RA and 49 osteoarthritis (OA) patients were obtained. Samples of different joints were collected from 7 patients with RA. The FLS invasiveness in Matrigel was studied, and the intraindividual and interindividual differences were compared. From the patients with FLS who exhibited the most extreme differences in in vitro ingrowth (most and least invasive FLS), radiographs of the hands and feet were collected and scored according to the Sharp/van der Heijde method to determine the relationship between in vitro invasion data and estimated yearly joint damage progression. FLS from patients with RA were more invasive than FLS from patients with OA (P < 0.001). The mean intraindividual variation in FLS invasion was much less than the mean interindividual variation (mean +/- SD 1,067 +/- 926 and 3,845 +/- 2,367 for intraindividual and interindividual variation, respectively; P = 0.035), which shows that the level of FLS invasion is a patient characteristic. The mean +/- SEM Sharp score on radiographs of the hands or feet divided by the disease duration was 4.4 +/- 1.1 units per year of disease duration in patients with the least invasive FLS (n = 9), which was much lower compared with the 21.8 +/- 3.1 units per year of disease duration in patients with the most invasive FLS (n = 9) (P < 0.001). The ex vivo invasive behavior of FLS from RA patients is associated with the rate of joint destruction and is a patient characteristic, given the much smaller intraindividual than interindividual FLS variation.

Inflammatory response of cultured rat synoviocytes challenged with synovial fluid from osteoarthritis patients correlates with their radiographic grading: a pilot study.

PubMed

Koppikar, Soumya J; Kulkarni, Priya G; Ingale, Dhanashri R; Shinde, Dattatray; Wagh, NarendraKumar; Deshpande, Shantanu; Moghe, Alpana S; Ranjekar, Prabhakar K; Harsulkar, Abhay M

2015-09-01

The inflammatory nature of synovial fluid (SF) of varying grade osteoarthritis (OA) patients was estimated by measuring pro-inflammatory factors and through a unique cell-challenge experiment. SF samples were collected from six OA and one non-OA patient; spanning Kellgren-Lawrence (KL) grades were analyzed for interlukin-1-beta (IL-1β), nitric oxide (NO) and its derivatives, and glycosaminoglycan (GAG). Levels of IL-1β, NO, and GAG in SF did not correlate with KL grades of the patients studied. In the cell-challenge experiment, cultured rat synoviocyte fibroblasts (RSFs) were challenged by the patient's SFs with and without pre-treatment of IL-1β and lipopolysaccharide (LPS). NO released by the cells was taken as an indicator of inflammation. SFs from KL grades 2 and 3 induced maximum inflammation in cultured RSFs (grade 2 64.61 ± 4.8 and 89.51 ± 5.6 μM/ml after 48 and 72 h, grade 3 58.27 ± 2.7 and 64.22 ± 2.8 μM/ml after 48 and 72 h, respectively). Similar trend was observed in RSF pretreated with either recombinant IL-1β or LPS suggesting that SF from patients KL grades 2 and 3 accumulates more pro-inflammatory factors. IL-1β-pre-treated RSFs challenged by SF for 72 h showed 234.41 ± 17.6 μM/ml increase (patient 3, grade 3), whereas higher NO after LPS pre-treatment was recorded (118.92 ± 6.2 μM/ml; patient 3, grade 3). Interestingly, SFs from grade 1 and non-OA patient could reduce released NO to 27.10 ± 2.2 μM/ml showing potency to alleviate inflammation. These interesting findings, however, need to be confirmed on a wider number of patients, which may offer significant therapeutic application in treatment of OA.

Aciculatin Inhibits Granulocyte Colony-Stimulating Factor Production by Human Interleukin 1β-Stimulated Fibroblast-Like Synoviocytes

PubMed Central

Shih, Kao-Shang; Wang, Jyh-Horng; Wu, Yi-Wen; Teng, Che-Ming; Chen, Chien-Chih; Yang, Chia-Ron

2012-01-01

The expression of granulocyte colony-stimulating factor (G-CSF), the major regulator of neutrophil maturation, by human fibroblast-like synoviocytes (FLS) can be stimulated by the inflammatory cytokine interleukin-1β (IL-1β). G-CSF is known to contribute to the pathologic processes of destructive arthritis, but the induction mechanism remains unknown. The aims of this study were to identify the signaling pathways involved in IL-1β-stimulated G-CSF production and to determine whether this process was inhibited by aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), the major bioactive component of Chrysopogon aciculatus. IL-1β-induced cytokine expression was evaluated by measuring mRNA and protein levels by RT-PCR, ELISA, and Milliplex® assay. Whether aciculatin inhibited IL-1β-stimulated G-CSF expression, and if so, how, were evaluated using western blot assay, an electrophoretic mobility shift assay, and a reporter gene assay. Neutrophil differentiation was determined by Wright-Giemsa staining and flow cytometry. Aciculatin markedly inhibited G-CSF expression induced by IL-1β (10 ng/mL) in a concentration-dependent manner (1–10 µM). In clarifying the mechanisms involved, aciculatin was found to inhibit the IL-1β-induced activation of the IκB kinase (IKK)/IκB/nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways by suppressing the DNA binding activity of the transcription factors NF-κB and activator protein (AP)-1. Furthermore, aciculatin significantly inhibited the G-CSF-mediated phosphorylation of Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Akt and neutrophil differentiation from precursor cells. Our results show that aciculatin inhibits IL-1β-stimulated G-CSF expression and the subsequent neutrophil differentiation, suggesting that it might have therapeutic potential for inflammatory arthritis. PMID:22860122

C5a aggravates dysfunction of the articular cartilage and synovial fluid in rats with knee joint immobilization.

PubMed

Lu, Wei; Wang, Lin; Yao, Jing; Wo, Chunxin; Chen, Yu

2018-06-22

Degenerative alterations in articular cartilage are involved in the pathogenesis of osteoarthritis. The present study aimed to evaluate the role of complement component 5a (C5a) in osteoarthritic alterations in the articular cartilage and synovialis via a joint immobilization (IM) rat model. Rats were assigned to three groups: Control, IM and IM+anti‑C5a antibody (IM+anti‑C5a) groups. A terminal deoxynucleotidyl transferase dUTP nick end labeling assay and hematoxylin and eosin staining were used to evaluate the morphological alterations in the articular cartilage and synovialis. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis, immunohistochemical analysis and western blotting were used to evaluate C5a expression in the articular cartilage and synovialis. An ELISA was used to evaluate C5a‑induced alterations in interleukin (IL)‑1β, IL‑17A and tumor necrosis factor (TNF)‑α levels in the serum and joint fluid. The results demonstrated that knee joint immobilization induced destruction of knee joint synovial fluid and cartilage in the IM and IM+anti‑C5a antibody groups. Immobilization significantly increased the expression levels of C5a in serum and joint fluid in the IM group. Immunohistochemistry, western blotting and RT‑qPCR analysis illustrated markedly increased expression of C5a in the IM group. Immobilization markedly increased the IL‑1β, IL‑17A and TNF‑α expression levels in the serum and joint fluid in the IM group. Anti‑C5a was able to decrease immobilization‑induced alterations in morphology and cytokines compared with the IM group. The expression of C5a was increased in synoviocytes and joint cartilage in the IM model. Pro‑inflammatory cytokines, including TNF‑α and IL‑1β were released in the activated synoviocytes via the induction of C5a, suggesting that C5a serves an important role in joint inflammatory processes.

Oxygen and indocyanine green loaded phase-transition nanoparticle-mediated photo-sonodynamic cytotoxic effects on rheumatoid arthritis fibroblast-like synoviocytes

PubMed Central

Tang, Qin; Cui, Jianyu; Tian, Zhonghua; Sun, Jiangchuan; Wang, Zhigang; Chang, Shufang; Zhu, Shenyin

2017-01-01

Background Photodynamic therapy and sonodynamic therapy are developing, minimally invasive, and site-specific modalities for cancer therapy. A combined strategy PSDT (photodynamic therapy followed by sonodynamic therapy) has been proposed in this study. Here, we aimed to develop novel biodegradable poly(DL-lactide-co-glycolic acid) phase-transition nanoparticles simultaneously loaded with oxygen and indocyanine green (OI-NPs) and to investigate the cytotoxic effects and the potential mechanisms of OI-NP–mediated PSDT on MH7A synoviocytes. Methods The OI-NPs were prepared using a modified double emulsion method and the physicochemical properties were determined. The cellular uptake of OI-NPs was detected by confocal microscopy and flow cytometry. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay, flow cytometry, and Hoechst 33342/propidium iodide double staining were used to determine the cytotoxic effect of OI-NP–mediated PSDT on MH7A cells. Fluorescence microscope and fluorescence microplate reader were used to detect reactive oxygen species (ROS) generation. Results The OI-NPs were a stable and efficient carrier to deliver oxygen and indocyanine green, and enhanced cellular uptake was observed in MH7A cells with the nanoparticles. OI-NP–mediated PSDT caused more serious cell damage and more evident cell apoptosis, compared with other groups. Furthermore, increased generation of intracellular ROS was detected in MH7A cells treated with PSDT. Interestingly, the OI-NP–mediated PSDT-induced cell viability loss was effectively rescued by pretreatment with the ROS scavenger N-acetylcysteine. Conclusion Multifunctional OI-NPs were successfully developed and characterized for the combined delivery of oxygen and indocyanine green, and OI-NP–mediated PSDT would be a potential cytotoxic treatment for MH7A cells. This study may provide a novel strategy for the treatment of RA and develop a model of theranostic application through phase-transition nanoparticle-mediated PSDT in the future. PMID:28123298

Histone deacetylase 3 regulates the inflammatory gene expression programme of rheumatoid arthritis fibroblast-like synoviocytes

PubMed Central

Angiolilli, Chiara; Kabala, Pawel A; Van Baarsen, Iris M; Ferguson, Bradley S; García, Samuel; Malvar Fernandez, Beatriz; McKinsey, Timothy A; Tak, Paul P; Fossati, Gianluca; Mascagni, Paolo; Baeten, Dominique L; Reedquist, Kris A

2017-01-01

Objectives Non-selective histone deacetylase (HDAC) inhibitors (HDACi) have demonstrated anti-inflammatory properties in both in vitro and in vivo models of rheumatoid arthritis (RA). Here, we investigated the potential contribution of specific class I and class IIb HDACs to inflammatory gene expression in RA fibroblast-like synoviocytes (FLS). Methods RA FLS were incubated with pan-HDACi (ITF2357, givinostat) or selective HDAC1/2i, HDAC3/6i, HDAC6i and HDAC8i. Alternatively, FLS were transfected with HDAC3, HDAC6 or interferon (IFN)-α/β receptor alpha chain (IFNAR1) siRNA. mRNA expression of interleukin (IL)-1β-inducible genes was measured by quantitative PCR (qPCR) array and signalling pathway activation by immunoblotting and DNA-binding assays. Results HDAC3/6i, but not HDAC1/2i and HDAC8i, significantly suppressed the majority of IL-1β-inducible genes targeted by pan-HDACi in RA FLS. Silencing of HDAC3 expression reproduced the effects of HDAC3/6i on gene regulation, contrary to HDAC6-specific inhibition and HDAC6 silencing. Screening of the candidate signal transducers and activators of transcription (STAT)1 transcription factor revealed that HDAC3/6i abrogated STAT1 Tyr701 phosphorylation and DNA binding, but did not affect STAT1 acetylation. HDAC3 activity was required for type I IFN production and subsequent STAT1 activation in FLS. Suppression of type I IFN release by HDAC3/6i resulted in reduced expression of a subset of IFN-dependent genes, including the chemokines CXCL9 and CXCL11. Conclusions Inhibition of HDAC3 in RA FLS largely recapitulates the effects of pan-HDACi in suppressing inflammatory gene expression, including type I IFN production in RA FLS. Our results identify HDAC3 as a potential therapeutic target in the treatment of RA and type I IFN-driven autoimmune diseases. PMID:27457515

The effect of multimeric adiponectin isoforms and leptin on the function of rheumatoid fibroblast-like synoviocytes.

PubMed

Kontny, E; Janicka, I; Skalska, U; Maśliński, W

2015-01-01

To evaluate the effects of physiologically relevant concentrations of multimeric adiponectin isoforms and leptin on the function of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). FLS, isolated from the synovial tissue of 21 RA patients, were stimulated for 24 h with interleukin (IL)-1β (1 ng/mL) and adiponectin isoforms [fraction enriched with high-molecular-weight (HMW) oligomers and middle-molecular-weight (MMW) hexamers or low-molecular-weight (LMW) trimers, 10 μg/mL each], or leptin (10 ng/mL), either separately or in a combination of IL-1β and the respective adipokine. Moreover, cells were pre-treated for 24 h with adipokines, then stimulated for 8 h with IL-1β. The concentrations of IL-6, IL-8, matrix metalloproteinase (MMP)-3, and dickkopf (DKK)-1, an inhibitor of osteoblastogenesis, in culture supernatants, as well as the concentrations of leptin, HMW, MMW, and LMW adiponectin in sera and synovial fluid (SF) samples, were measured by specific enzyme-linked immunosorbent assays (ELISAs). In comparison with sera, SF samples contained similar amounts of leptin, lower amounts of total adiponectin but a higher proportion of the LMW isoform. Separately added IL-1β and HMW/MMW adiponectin, but not LMW adiponectin or leptin, up-regulated the release of IL-6, IL-8, and MMP-3 from FLS but no synergy was observed in co-stimulation experiments. However, pre-treatment of FLS with HMW/MMW or LMW significantly raised the IL-1β-triggered secretion of MMP-3 and IL-6 or MMP-3, respectively. Adiponectin not only triggers pro-inflammatory and pro-destructive activities of rheumatoid FLS but also pre-disposes these cells to a stronger response to IL-1β. Thus, it is likely that adiponectin is more important in the initiation phase than in the chronic phase of RA.

Hyaluronic acid synthase-2 gene transfer into the joints of Beagles by use of recombinant adeno-associated viral vectors.

PubMed

Kyostio-Moore, Sirkka; Berthelette, Patricia; Cornell, Cathleen Sookdeo; Nambiar, Bindu; Figueiredo, Monica Dias

2018-05-01

OBJECTIVE To evaluate gene transfer of recombinant adeno-associated viral (rAAV) vectors with AAV2 or AAV5 capsid and encoding hyaluronic acid (HA) synthase-2 (HAS2) into joints of healthy dogs. ANIMALS 22 purpose-bred Beagles. PROCEDURES Plasmid expression cassettes encoding canine HAS2 (cHAS2) were assessed in vitro for concentration and molecular size of secreted HA. Thereafter, rAAV2-cHAS2 vectors at 3 concentrations and rAAV5-cHAS2 vectors at 1 concentration were each administered intra-articularly into the left stifle joint of 5 dogs; 2 dogs received PBS solution instead. Synovial fluid HA concentration and serum and synovial fluid titers of neutralizing antibodies against AAV capsids were measured at various points. Dogs were euthanized 28 days after treatment, and cartilage and synovium samples were collected for vector DNA and mRNA quantification and histologic examination. RESULTS Cell transfection with plasmids encoding cHAS2 resulted in an increase in production and secretion of HA in vitro. In vivo, the rAAV5-cHAS2 vector yielded uniform genome transfer and cHAS2 expression in collected synovium and cartilage samples. In contrast, rAAV2-cHAS2 vectors were detected inconsistently in synovium and cartilage samples and failed to produce clear dose-related responses. Histologic examination revealed minimal synovial inflammation in joints injected with rAAV vectors. Neutralizing antibodies against AAV capsids were detected in serum and synovial fluid samples from all vector-treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE rAAV5-mediated transfer of the gene for cHAS2 into healthy joints of dogs by intra-articular injection appeared safe and resulted in vector-derived cHAS2 production by synoviocytes and chondrocytes. Whether this treatment may increase HA production by synoviocytes and chondrocytes in osteoarthritic joints remains to be determined.

The fluence effects of low-level laser therapy on inflammation, fibroblast-like synoviocytes, and synovial apoptosis in rats with adjuvant-induced arthritis.

PubMed

Hsieh, Yueh-Ling; Cheng, Yu-Jung; Huang, Fang-Chuen; Yang, Chen-Chia

2014-12-01

The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) operating at low and high fluences on joint inflammation, fibroblast-like synoviocytes (FLS), and synovial apoptosis in rats with adjuvant-induced arthritis. Rheumatoid arthritis (RA) is characterized by pronounced inflammation and FLS proliferation within affected joints. Certain data indicate that LLLT is effective in patients with inflammation caused by RA; however, the fluence effects of LLLT on synovium are unclear. Monoarthritis was induced in adult male Sprague-Dawley rats (250-300 g) via intraarticular injection of complete Freund's adjuvant (CFA) into the tibiotarsal joint. Animals were irradiated 72 h after CFA administration with a 780 nm GaAlAs laser at 4.5 J/cm2 (30 mW, 30 sec/spot) and 72 J/cm2 (80 mW, 180 sec/spot) daily for 10 days. After LLLT, the animals were euthanized and their arthritic ankles were collected for histopathological analysis, immunoassays of tumor necrosis factor (TNF)-α, matrix metallopeptidase (MMP)3 and 5B5, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. LLLT at a fluence of 4.5 J/cm2 significantly reduced infiltration of inflammatory cells and expressions of TNF-α-, MMP3- and 5B5-like immunoreactivities, as well as resulting in more TUNEL-positive apoptotic cells in the synovium. No significant changes were observed in these biochemicals and inflammation in arthritic animals treated with 72 J/cm2. LLLT with low fluence is highly effective in reducing inflammation to sites of injury by decreasing the numbers of FLS, inflammatory cells, and mediators in the CFA-induced arthritic model. These data will be of value in designing clinical trials of LLLT for RA.

The Fluence Effects of Low-Level Laser Therapy on Inflammation, Fibroblast-Like Synoviocytes, and Synovial Apoptosis in Rats with Adjuvant-Induced Arthritis

PubMed Central

Hsieh, Yueh-Ling; Cheng, Yu-Jung; Huang, Fang-Chuen

2014-01-01

Abstract Objective: The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) operating at low and high fluences on joint inflammation, fibroblast-like synoviocytes (FLS), and synovial apoptosis in rats with adjuvant-induced arthritis. Background data: Rheumatoid arthritis (RA) is characterized by pronounced inflammation and FLS proliferation within affected joints. Certain data indicate that LLLT is effective in patients with inflammation caused by RA; however, the fluence effects of LLLT on synovium are unclear. Methods: Monoarthritis was induced in adult male Sprague–Dawley rats (250–300 g) via intraarticular injection of complete Freund's adjuvant (CFA) into the tibiotarsal joint. Animals were irradiated 72 h after CFA administration with a 780 nm GaAlAs laser at 4.5 J/cm2 (30 mW, 30 sec/spot) and 72 J/cm2 (80 mW, 180 sec/spot) daily for 10 days. After LLLT, the animals were euthanized and their arthritic ankles were collected for histopathological analysis, immunoassays of tumor necrosis factor (TNF)-α, matrix metallopeptidase (MMP)3 and 5B5, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. Results: LLLT at a fluence of 4.5 J/cm2 significantly reduced infiltration of inflammatory cells and expressions of TNF-α-, MMP3- and 5B5-like immunoreactivities, as well as resulting in more TUNEL-positive apoptotic cells in the synovium. No significant changes were observed in these biochemicals and inflammation in arthritic animals treated with 72 J/cm2. Conclusions: LLLT with low fluence is highly effective in reducing inflammation to sites of injury by decreasing the numbers of FLS, inflammatory cells, and mediators in the CFA-induced arthritic model. These data will be of value in designing clinical trials of LLLT for RA. PMID:25394331

Follistatin-like protein 1 induction of matrix metalloproteinase 1, 3 and 13 gene expression in rheumatoid arthritis synoviocytes requires MAPK, JAK/STAT3 and NF-κB pathways.

PubMed

Ni, Su; Li, Chenkai; Xu, Nanwei; Liu, Xi; Wang, Wei; Chen, Wenyang; Wang, Yuji; van Wijnen, Andre J

2018-06-22

Elevated levels of follistatin-like protein 1 (FSTL1) have been found both in mouse models for human rheumatoid arthritis (RA) and collagen-induced arthritis (CIA). In this study, we elucidated the potential mechanisms by which FSTL1 contributes to the pathogenesis of RA. Fibroblast-like synoviocytes (FLSs) were established from synovial tissues of RA patients and stimulated with human recombinant FSTL1. Protein and mRNA expression levels of select matrix metalloproteinases (i.e., MMP1, MMP3, MMP13) in FLS were measured by, respectively, real-time RT-qPCR and ELISA. Activation of MAPK and other pathways that affect MMPs were evaluated by Western blotting. We also compared concentrations of MMPs in plasma in RA patients versus healthy controls (HC). Expression levels of MMP1, MMP3, and MMP13 were clearly stimulated by FSTL1 in vitro. FSTL1 activated the inflammation-related NF-κB signaling pathway, as well as all three mitogen-activated protein kinase (MAPK) pathways and the JAK/STAT3 pathway. Moreover, select chemical inhibitors that target p38 (SB203580), Erk1/2 (SP600125), JNK (SCH772984), STAT3 (AG490), and NF-κB (BAY 11-7082) significantly attenuated MMP expression. Inhibition of Toll-like receptor 4 by compound TAK-242 significantly abolished those effects of FSTL1. Importantly, elevated plasma concentrations of MMP3 were found to correlate with plasma FSTL1 levels in RA patients. These findings suggest that FSTL1 accelerates RA progression by activating MAPK, JAK/STAT3, and NF-κB pathways to enhance secretion of different MMPs and this enhancement is via TLR4. Targeting FSTL1 may provide a promising pharmacological drug therapy to ameliorate RA symptoms and perhaps reverse disease progression. © 2018 Wiley Periodicals, Inc.

A new rational-based optimal design strategy of ship structure based on multi-level analysis and super-element modeling method

NASA Astrophysics Data System (ADS)

Sun, Li; Wang, Deyu

2011-09-01

A new multi-level analysis method of introducing the super-element modeling method, derived from the multi-level analysis method first proposed by O. F. Hughes, has been proposed in this paper to solve the problem of high time cost in adopting a rational-based optimal design method for ship structural design. Furthermore, the method was verified by its effective application in optimization of the mid-ship section of a container ship. A full 3-D FEM model of a ship, suffering static and quasi-static loads, was used as the analyzing object for evaluating the structural performance of the mid-ship module, including static strength and buckling performance. Research results reveal that this new method could substantially reduce the computational cost of the rational-based optimization problem without decreasing its accuracy, which increases the feasibility and economic efficiency of using a rational-based optimal design method in ship structural design.

Investigations of formation of quasi-static vortex-structures in granular bodies using DEM

NASA Astrophysics Data System (ADS)

Kozicki, Jan; Tejchman, Jacek

2017-06-01

The paper presents some two-dimensional simulation results of vortex-structures in cohesionless initially dense sand during quasi-static passive wall translation. The sand behaviour was simulated using the discrete element method (DEM). Sand grains were modelled by spheres with contact moments to approximately capture the irregular grain shape. In order to detect vortex-structures, the Helmholtz-Hodge decomposition of a flow displacement field from DEM calculations was used. This approach enabled us to distinguish both incompressibility and vorticity in the granular displacement field.

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST TOWER VIEW INCLUDES STRUCTURAL DYNAMICS TEST STAND COLD CALIBRATION TEST STAND AND COMPONENTS TEST LAB. - Marshall Space Flight Center, East Test Area, Dodd Road, Huntsville, Madison County, AL

[Expression of CXCL16/CXCR6 in fibroblast-like synoviocytes in rheumatoid arthritis and its role in synoviocyte proliferation].

PubMed

Zhang, X; Zhao, J X; Sun, L; Liu, X Y

2017-08-18

It has been found that serum CXCL16 concentration in rheumatoid arthritis (RA) patients are significantly higher than those in osteoarthritis (OA) and normal subjects, and are positively correlated with disease activity and bone erosion. However, how is CXCL16 involved in the pathogenesis of RA is unclear. To evaluate the expression of CXCL16 and its receptor CXCR6 in fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) patients, and to explore the role of CXCL16 in the proliferation of RA-FLS. FLS were isolated from knee synovial tissues obtained from 8 patients of RA, 7 osteoarthritis (OA) and 3 normal controls. The diagnosis of RA was in line with the 1987 American Rheumatology Association (ACR) RA classification criteria, osteoarthritis met the 1996 ACR revised knee osteoarthritis classification criteria. Control synovium were obtained from trauma caused knee joint injury in healthy individuals who required surgery. Human knee FLS were cultured by tissue explants adherent method.FLS between passages 3 and 5 were used in the experiment. Expression of CXCL16 and its receptor CXCR6 were performed in Western blot analysis. FLS proliferation following stimulation with TNF-α and different concentrations of CXCL16 was examined by cell counting kit-8 (CCK-8). Expression of phosphorylated AKT (pAKT) in RA-FLS stimulated by CXCL16 was quantified by Western blot. Different concentrations of recombinant human CXCL16 were added to the culture medium of RA-FLS. After 48 h culture, supernantants were collected, and TNF-α, IL-6, RANKL and MMP3 in culture supernatants of RA-FLS were determined by enzyme-linked immunosorbent assays (ELISA) operated following the kit instructions. Expression of CXCL16 and CXCR6 in RA-FLS was significantly higher than that of OA and controls (P<0.05), but no significant difference was found between OA-FLS and control FLS. Proliferation of RA-FLS was markedly up-regulated after stimulation of CXCL16 (P <0.05). In the case of the CXCL16 stimulated OA-FLS and control FLS, the FLS proliferation remained basically unchanged. Expression of phosphorylated AKT in RA-FLS increased remarkably in condition of CXCL16 (50,100, 200 μg/L) stimulation. The levels of IL-6 and RANKL in culture supernatants of RA-FLS were obviously increased under CXCL16 (200 μ g/L) stimulation, while TNF-α and MMP-3 levels in the culture supernatants remained unchanged after CXCL16 (200 μg/L) stimulation. This study shows that the expression of CXCL16 and its receptor was highly elevated in RA-FLS. Recombinant CXCL16 promoted RA-FLS proliferation and activation in vitro. All these indicate that CXCL16 play an important role in the pathogenesis of RA, anti-CXCL16 treatment may help to relieve inflammation and bone damage of RA patients. However, due to the limitations of this study, the role of CXCL16 and its receptors in RA-FLS remains to be elucidated by further research.

Bias field tunable magnetic configuration and magnetization dynamics in Ni80Fe20 nano-cross structures with varying arm length

NASA Astrophysics Data System (ADS)

Adhikari, K.; Choudhury, S.; Mandal, R.; Barman, S.; Otani, Y.; Barman, A.

2017-01-01

Ferromagnetic nano-cross structures promise exotic static magnetic configurations and very rich and tunable magnetization dynamics leading towards potential applications in magnetic logic and communication devices. Here, we report an experimental study of external magnetic field tunable static magnetic configurations and magnetization dynamics in Ni80Fe20 nano-cross structures with varying arm lengths (L). Broadband ferromagnetic resonance measurements showed a strong variation in the number of spin-wave (SW) modes and mode frequencies (f) with bias field magnitude (H). Simulated static magnetic configurations and SW mode profiles explain the rich variation of the SW spectra, including mode softening, mode crossover, mode splitting, and mode merging. Such variation of SW spectra is further modified by the size of the nano-cross. Remarkably, with decreasing arm length of nano-cross structures, the onion magnetization ground state becomes more stable. Calculated magnetostatic field distributions support the above observations and revealed the non-collective nature of the dynamics in closely packed nano-cross structures. The latter is useful for their possible applications in magnetic storage and memory devices.

Learning Enterprise Malware Triage from Automatic Dynamic Analysis

DTIC Science & Technology

2013-03-01

Kolter and Maloof n-gram method, Dube’s malware target recognition (MaTR) static method performs significantly more accurately at the 95% confidence...from the static method as in Kolter and Maloof. The MIST approach with behavior sequences 9 allows researchers to tailor the level of analysis to the...citations, none publish work that implements it. Only Kolter and Maloof use nearly as long gram structures, although that research uses static grams rather

Effects of combustibles on internal quasi-static loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandoval, N.R.; Hokanson, J.C.; Esparza, E.D.

1984-08-01

The phenomenon of quasi-static pressure enhancement produced when combustible materials are placed near HE sources has been recently discovered. The effects of placing solid and liquid combustible materials near detonating explosives on internal blast loading was measured during tests conducted in a one-eighth scale model of a containment structure. In many cases, dramatic increases in gas pressures resulted. Principal conclusions of this study are: combustible materials near explosives can markedly increase gas pressures in enclosed structures; there is a lack of data on HE-combustible combinations; quasi-static loading calculations should include estimates of contributions from the burning of combustible materials whenevermore » such materials are expected to be in intimate contact with HE sources; and effects of combustibles should be investigated further to determine methods for prediction. Variations in charge to combustible mass, charge type, structure volume, degree of venting and degree of contact between HE and combustible sbould be studied.« less

Thermophysical properties of liquid Ni around the melting temperature from molecular dynamics simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozas, R. E.; Department of Physics, University of Bío-Bío, Av. Collao 1202, P.O. Box 5C, Concepción; Demiraǧ, A. D.

Thermophysical properties of liquid nickel (Ni) around the melting temperature are investigated by means of classical molecular dynamics (MD) simulation, using three different embedded atom method potentials to model the interactions between the Ni atoms. Melting temperature, enthalpy, static structure factor, self-diffusion coefficient, shear viscosity, and thermal diffusivity are compared to recent experimental results. Using ab initio MD simulation, we also determine the static structure factor and the mean-squared displacement at the experimental melting point. For most of the properties, excellent agreement is found between experiment and simulation, provided the comparison relative to the corresponding melting temperature. We discuss themore » validity of the Hansen-Verlet criterion for the static structure factor as well as the Stokes-Einstein relation between self-diffusion coefficient and shear viscosity. The thermal diffusivity is extracted from the autocorrelation function of a wavenumber-dependent temperature fluctuation variable.« less

Thermodynamic properties and static structure factor for a Yukawa fluid in the mean spherical approximation.

PubMed

Montes-Perez, J; Cruz-Vera, A; Herrera, J N

2011-12-01

This work presents the full analytic expressions for the thermodynamic properties and the static structure factor for a hard sphere plus 1-Yukawa fluid within the mean spherical approximation. To obtain these properties of the fluid type Yukawa analytically it was necessary to solve an equation of fourth order for the scaling parameter on a large scale. The physical root of this equation was determined by imposing physical conditions. The results of this work are obtained from seminal papers of Blum and Høye. We show that is not necessary the use the series expansion to solve the equation for the scaling parameter. We applied our theoretical result to find the thermodynamic and the static structure factor for krypton. Our results are in good agreement with those obtained in an experimental form or by simulation using the Monte Carlo method.

Scaling effects in the static and dynamic response of graphite-epoxy beam-columns. Ph.D. Thesis - Virginia Polytechnic Inst. and State Univ.

NASA Technical Reports Server (NTRS)

Jackson, Karen E.

1990-01-01

Scale model technology represents one method of investigating the behavior of advanced, weight-efficient composite structures under a variety of loading conditions. It is necessary, however, to understand the limitations involved in testing scale model structures before the technique can be fully utilized. These limitations, or scaling effects, are characterized. in the large deflection response and failure of composite beams. Scale model beams were loaded with an eccentric axial compressive load designed to produce large bending deflections and global failure. A dimensional analysis was performed on the composite beam-column loading configuration to determine a model law governing the system response. An experimental program was developed to validate the model law under both static and dynamic loading conditions. Laminate stacking sequences including unidirectional, angle ply, cross ply, and quasi-isotropic were tested to examine a diversity of composite response and failure modes. The model beams were loaded under scaled test conditions until catastrophic failure. A large deflection beam solution was developed to compare with the static experimental results and to analyze beam failure. Also, the finite element code DYCAST (DYnamic Crash Analysis of STructure) was used to model both the static and impulsive beam response. Static test results indicate that the unidirectional and cross ply beam responses scale as predicted by the model law, even under severe deformations. In general, failure modes were consistent between scale models within a laminate family; however, a significant scale effect was observed in strength. The scale effect in strength which was evident in the static tests was also observed in the dynamic tests. Scaling of load and strain time histories between the scale model beams and the prototypes was excellent for the unidirectional beams, but inconsistent results were obtained for the angle ply, cross ply, and quasi-isotropic beams. Results show that valuable information can be obtained from testing on scale model composite structures, especially in the linear elastic response region. However, due to scaling effects in the strength behavior of composite laminates, caution must be used in extrapolating data taken from a scale model test when that test involves failure of the structure.

The European Spacelab structural design evolution

NASA Technical Reports Server (NTRS)

Thirkettle, A. J.

1982-01-01

Spacelab is a manned, reusable laboratory which is being developed for the European Space Agency (ESA). In its working mode it will fly in low earth orbit in the cargo bay of the Shuttle Transportation System (STS) Orbiter. A description is presented of the structural development of the various features of Spacelab. System requirements are considered along with structural requirements, quasi-static loads, acoustic loads, pressure loads, crash loads, ground loads, and the fatigue profile. Aspects of thermal environment generation are discussed, and questions regarding the design evolution of the pallet structure are examined. Details of pallet structure testing are reported, taking into account static strength tests, acoustic tests, the modal survey test, crash tests, and fatigue/fracture mechanics testing.

NASTRAN/FLEXSTAB procedure for static aeroelastic analysis

NASA Technical Reports Server (NTRS)

Schuster, L. S.

1984-01-01

Presented is a procedure for using the FLEXSTAB External Structural Influence Coefficients (ESIC) computer program to produce the structural data necessary for the FLEXSTAB Stability Derivatives and Static Stability (SD&SS) program. The SD&SS program computes trim state, stability derivatives, and pressure and deflection data for a flexible airplane having a plane of symmetry. The procedure used a NASTRAN finite-element structural model as the source of structural data in the form of flexibility matrices. Selection of a set of degrees of freedom, definition of structural nodes and panels, reordering and reformatting of the flexibility matrix, and redistribution of existing point mass data are among the topics discussed. Also discussed are boundary conditions and the NASTRAN substructuring technique.

Correlating Structural Order with Structural Rearrangement in Dusty Plasma Liquids: Can Structural Rearrangement be Predicted by Static Structural Information?

NASA Astrophysics Data System (ADS)

Su, Yen-Shuo; Liu, Yu-Hsuan; I, Lin

2012-11-01

Whether the static microstructural order information is strongly correlated with the subsequent structural rearrangement (SR) and their predicting power for SR are investigated experimentally in the quenched dusty plasma liquid with microheterogeneities. The poor local structural order is found to be a good alarm to identify the soft spot and predict the short term SR. For the site with good structural order, the persistent time for sustaining the structural memory until SR has a large mean value but a broad distribution. The deviation of the local structural order from that averaged over nearest neighbors serves as a good second alarm to further sort out the short time SR sites. It has the similar sorting power to that using the temporal fluctuation of the local structural order over a small time interval.

Soya-cerebroside, an extract of Cordyceps militaris, suppresses monocyte migration and prevents cartilage degradation in inflammatory animal models

PubMed Central

Liu, Shan-Chi; Chiu, Ching-Peng; Tsai, Chun-Hao; Hung, Chun-Yin; Li, Te-Mao; Wu, Yang-Chang; Tang, Chih-Hsin

2017-01-01

Pathophysiological events that modulate the progression of structural changes in osteoarthritis (OA) include the secretion of inflammatory molecules, such as proinflammatory cytokines. Interleukin-1beta (IL-1β) is the prototypical inflammatory cytokine that activates OA synovial cells to release cytokines and chemokines in support of the inflammatory response. The monocyte chemoattractant protein-1 (MCP-1/CCL2) is one of the key chemokines that regulate migration and infiltration of monocytes in response to inflammation. We show in this study that IL-1β-induced MCP-1 expression and monocyte migration in OA synovial fibroblasts (OASFs) is effectively inhibited by soya-cerebroside, an extract of Cordyceps militaris. We found that soya-cerebroside up-regulated of microRNA (miR)-432 expression via inhibiting AMPK and AKT signaling pathways in OASFs. Soya-cerebroside also effectively decreased monocyte infiltration and prevented cartilage degradation in a rat inflammatory model. Our findings are the first to demonstrate that soya-cerebroside inhibits monocyte/macrophage infiltration into synoviocytes, attenuating synovial inflammation and preventing cartilage damage by reducing MCP-1 expression in vitro and in vivo. Taken together, we suggest a novel therapeutic strategy based on the use of soya-cerebroside for the management of OA. PMID:28225075

How does tissue regeneration influence the mechanical behavior of additively manufactured porous biomaterials?

PubMed

Hedayati, R; Janbaz, S; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

2017-01-01

Although the initial mechanical properties of additively manufactured porous biomaterials are intensively studied during the last few years, almost no information is available regarding the evolution of the mechanical properties of implant-bone complex as the tissue regeneration progresses. In this paper, we studied the effects of tissue regeneration on the static and fatigue behavior of selective laser melted porous titanium structures with three different porosities (i.e. 77, 81, and 85%). The porous structures were filled with four different polymeric materials with mechanical properties in the range of those observed for de novo bone (0.7GPa

Homogentisate 1,2 dioxygenase is expressed in human osteoarticular cells: implications in alkaptonuria.

PubMed

Laschi, Marcella; Tinti, Laura; Braconi, Daniela; Millucci, Lia; Ghezzi, Lorenzo; Amato, Loredana; Selvi, Enrico; Spreafico, Adriano; Bernardini, Giulia; Santucci, Annalisa

2012-09-01

Alkaptonuria (AKU) results from defective homogentisate1,2-dioxygenase (HGD), causing degenerative arthropathy. The deposition of ochronotic pigment in joints is so far attributed to homogentisic acid produced by the liver, circulating in the blood and accumulating locally. Human normal and AKU osteoarticular cells were tested for HGD gene expression by RT-PCR, mono- and 2D-Western blotting. HGD gene expression was revealed in chondrocytes, synoviocytes, osteoblasts. Furthermore, HGD expression was confirmed by Western blotting, that also revealed the presence of five enzymatic molecular species. Our findings indicate that AKU osteoarticular cells produce the ochronotic pigment in loco and this may strongly contribute to induction of ochronotic arthropathy. Copyright © 2011 Wiley Periodicals, Inc.

Evaluation of High-Precision Sensors in Structural Monitoring

PubMed Central

Erol, Bihter

2010-01-01

One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant. PMID:22163499

University Engineering Design Challenge

DTIC Science & Technology

2015-01-02

strength its members provide. Trusses are common load - bearing structures, and are found in many modern-day applications due to their simple, strong, and...we ran simulations on was one of the member arms. We applied a bearing load on the surfaces of the holes on one side and tested it for static stress...73.24 ksi yield strength as shown figures 17 below. Figure 17: von Mises stress under static bearing load of 8750 lb. Under the static bearing load

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE A JUPITER MISSILE IS BEING POSITIONED ONTO THE TEST TOWER. DATE AND PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Static, Dynamic, and Fatigue Analysis of the Mechanical System of Ultrasonic Scanner for Inservice Inspection of Research Reactors

NASA Astrophysics Data System (ADS)

Awwaluddin, Muhammad; Kristedjo, K.; Handono, Khairul; Ahmad, H.

2018-02-01

This analysis is conducted to determine the effects of static and dynamic loads of the structure of mechanical system of Ultrasonic Scanner i.e., arm, column, and connection systems for inservice inspection of research reactors. The analysis is performed using the finite element method with 520 N static load. The correction factor of dynamic loads used is the Gerber mean stress correction (stress life). The results of the analysis show that the value of maximum equivalent von Mises stress is 1.3698E8 Pa for static loading and value of the maximum equivalent alternating stress is 1.4758E7 Pa for dynamic loading. These values are below the upper limit allowed according to ASTM A240 standards i.e. 2.05E8 Pa. The result analysis of fatigue life cycle are at least 1E6 cycle, so it can be concluded that the structure is in the high life cycle category.

Flow motifs reveal limitations of the static framework to represent human interactions

NASA Astrophysics Data System (ADS)

Rocha, Luis E. C.; Blondel, Vincent D.

2013-04-01

Networks are commonly used to define underlying interaction structures where infections, information, or other quantities may spread. Although the standard approach has been to aggregate all links into a static structure, some studies have shown that the time order in which the links are established may alter the dynamics of spreading. In this paper, we study the impact of the time ordering in the limits of flow on various empirical temporal networks. By using a random walk dynamics, we estimate the flow on links and convert the original undirected network (temporal and static) into a directed flow network. We then introduce the concept of flow motifs and quantify the divergence in the representativity of motifs when using the temporal and static frameworks. We find that the regularity of contacts and persistence of vertices (common in email communication and face-to-face interactions) result on little differences in the limits of flow for both frameworks. On the other hand, in the case of communication within a dating site and of a sexual network, the flow between vertices changes significantly in the temporal framework such that the static approximation poorly represents the structure of contacts. We have also observed that cliques with 3 and 4 vertices containing only low-flow links are more represented than the same cliques with all high-flow links. The representativity of these low-flow cliques is higher in the temporal framework. Our results suggest that the flow between vertices connected in cliques depend on the topological context in which they are placed and in the time sequence in which the links are established. The structure of the clique alone does not completely characterize the potential of flow between the vertices.

Effects of bio-functionalizing surface treatments on the mechanical behavior of open porous titanium biomaterials.

PubMed

Amin Yavari, S; Ahmadi, S M; van der Stok, J; Wauthle, R; Riemslag, A C; Janssen, M; Schrooten, J; Weinans, H; Zadpoor, A A

2014-08-01

Bio-functionalizing surface treatments are often applied for improving the bioactivity of biomaterials that are based on otherwise bioinert titanium alloys. When applied on highly porous titanium alloy structures intended for orthopedic bone regeneration purposes, such surface treatments could significantly change the static and fatigue properties of these structures and, thus, affect the application of the biomaterial as bone substitute. Therefore, the interplay between biofunctionalizing surface treatments and mechanical behavior needs to be controlled. In this paper, we studied the effects of two bio-functionalizing surface treatments, namely alkali-acid heat treatment (AlAcH) and acid-alkali (AcAl), on the static and fatigue properties of three different highly porous titanium alloy implants manufactured using selective laser melting. It was found that AlAcH treatment results in minimal mass loss. The static and fatigue properties of AlAcH specimens were therefore not much different from as-manufactured (AsM) specimens. In contrast, AcAl resulted in substantial mass loss and also in significantly less static and fatigue properties particularly for porous structures with the highest porosity. The ratio of the static mechanical properties of AcAl specimens to that of AsM specimen was in the range of 1.5-6. The fatigue lives of AcAl specimens were much more severely affected by the applied surface treatments with fatigue lives up to 23 times smaller than that of AsM specimens particularly for the porous structures with the highest porosity. In conclusion, the fatigue properties of surface treated porous titanium are dependent not only on the type of applied surface treatment but also on the porosity of the biomaterial. Copyright © 2014 Elsevier Ltd. All rights reserved.

Broadband polarizing beam splitter based on the form birefringence of a subwavelength grating in the quasi-static domain.

PubMed

Yi, Deer; Yan, Yingbai; Liu, Haitao; Lu, Si; Jin, Guofan

2004-04-01

We propose a novel broadband polarizing beam splitter with a compact sandwich structure that has a subwavelength grating in the quasi-static domain as the filling. The design is based on effective-medium theory an anisotropic thin-film theory, and the performance is investigated with rigorous coupled-wave theory. The design results show that the structure can provide a high polarization extinction ratio in a broad spectral range.

Control of the surface quality parameters of machine components during static pulsed treatment

NASA Astrophysics Data System (ADS)

Komkov, V. A.; Rabinskii, L. N.; Kokoreva, O. G.; Kuprikov, N. M.

2016-12-01

A technique is developed to determine the homogeneity of the structure in a surface layer subjected to strain hardening. Static pulsed treatment is found to be one of the most effective surface plastic deformation methods that can be used to control the uniformity of hardening a surface layer. This treatment makes it possible to create a hardened surface layer to a depth of 10 mm with a homogeneous or heterogeneous structure.

Ab initio study of several static and dynamic properties of bulk liquid Ni near melting

NASA Astrophysics Data System (ADS)

del Rio, B. G.; González, L. E.; González, D. J.

2017-01-01

Several static and dynamic properties of bulk liquid Ni at a thermodynamic state near its triple point have been evaluated by ab initio molecular dynamics simulations. The calculated static structure shows very good agreement with the available experimental data, including an asymmetric second peak in the static structure factor, which underlines a marked local icosahedral short-range order in the liquid. The dynamical structure reveals propagating density fluctuations, and the calculated dynamic structure factors, S (q ,ω ) , show a good agreement with the inelastic x-ray scattering measurements. The obtained dispersion relation closely follows that obtained from the inelastic x-ray scattering measurements; moreover we analyze the possible reasons behind its discrepancy with respect to the dispersion relation derived from the inelastic neutron scattering data. The dynamical processes behind the S (q ,ω ) have been analyzed by using a model with two decay channels (a fast and a slow) associated with the relaxations of the collective excitations. We have found that the transverse current spectral functions exhibit some features which, so far, had previously been shown by high pressure liquid metals only. Furthermore, the calculated S (q ,ω ) show, within some q-range, the appearance of transverse-like excitation modes, similar to those recently found in other liquid metals. Finally, results are also reported for several transport coefficients.

The surface and deep structure of the waterfall illusion.

PubMed

Wade, Nicholas J; Ziefle, Martina

2008-11-01

The surface structure of the waterfall illusion or motion aftereffect (MAE) is its phenomenal visibility. Its deep structure will be examined in the context of a model of space and motion perception. The MAE can be observed following protracted observation of a pattern that is translating, rotating, or expanding/contracting, a static pattern appears to move in the opposite direction. The phenomenon has long been known, and it continues to present novel properties. One of the novel features of MAEs is that they can provide an ideal visual assay for distinguishing local from global processes. Motion during adaptation can be induced in a static central grating by moving surround gratings; the MAE is observed in the static central grating but not in static surrounds. The adaptation phase is local and the test phase is global. That is, localised adaptation can be expressed in different ways depending on the structure of the test display. These aspects of MAEs can be exploited to determine a variety of local/global interactions. Six experiments on MAEs are reported. The results indicated that relational motion is required to induce an MAE; the region adapted extends beyond that stimulated; storage can be complete when the MAE is not seen during the storage period; interocular transfer (IOT) is around 30% of monocular MAEs with phase alternation; large field spiral patterns yield MAEs with characteristic monocular and binocular interactions.

Effects of scaffold architecture on mechanical characteristics and osteoblast response to static and perfusion bioreactor cultures.

PubMed

Bartnikowski, Michal; Klein, Travis J; Melchels, Ferry P W; Woodruff, Maria A

2014-07-01

Tissue engineering focuses on the repair and regeneration of tissues through the use of biodegradable scaffold systems that structurally support regions of injury while recruiting and/or stimulating cell populations to rebuild the target tissue. Within bone tissue engineering, the effects of scaffold architecture on cellular response have not been conclusively characterized in a controlled-density environment. We present a theoretical and practical assessment of the effects of polycaprolactone (PCL) scaffold architectural modifications on mechanical and flow characteristics as well as MC3T3-E1 preosteoblast cellular response in an in vitro static plate and custom-designed perfusion bioreactor model. Four scaffold architectures were contrasted, which varied in inter-layer lay-down angle and offset between layers, while maintaining a structural porosity of 60 ± 5%. We established that as layer angle was decreased (90° vs. 60°) and offset was introduced (0 vs. 0.5 between layers), structural stiffness, yield stress, strength, pore size, and permeability decreased, while computational fluid dynamics-modeled wall shear stress was increased. Most significant effects were noted with layer offset. Seeding efficiencies in static culture were also dramatically increased due to offset (∼ 45% to ∼ 86%), with static culture exhibiting a much higher seeding efficiency than perfusion culture. Scaffold architecture had minimal effect on cell response in static culture. However, architecture influenced osteogenic differentiation in perfusion culture, likely by modifying the microfluidic environment. © 2014 Wiley Periodicals, Inc.

Investigation of Gearbox Vibration Transmission Paths on Gear Condition Indicator Performance

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Islam, AKM Anwarul; Feldman, Jason; Larsen, Chris

2013-01-01

Helicopter health monitoring systems use vibration signatures generated from damaged components to identify transmission faults. For damaged gears, these signatures relate to changes in dynamics due to the meshing of the damaged tooth. These signatures, referred to as condition indicators (CI), can perform differently when measured on different systems, such as a component test rig, or a full-scale transmission test stand, or an aircraft. These differences can result from dissimilarities in systems design and environment under dynamic operating conditions. The static structure can also filter the response between the vibration source and the accelerometer, when the accelerometer is installed on the housing. To assess the utility of static vibration transfer paths for predicting gear CI performance, measurements were taken on the NASA Glenn Spiral Bevel Gear Fatigue Test Rig. The vibration measurements were taken to determine the effect of torque, accelerometer location and gearbox design on accelerometer response. Measurements were taken at the housing and compared while impacting the gear set near mesh. These impacts were made at gear mesh to simulate gear meshing dynamics. Data measured on a helicopter gearbox installed in a static fixture were also compared to the test rig. The behavior of the structure under static conditions was also compared to CI values calculated under dynamic conditions. Results indicate that static vibration transfer path measurements can provide some insight into spiral bevel gear CI performance by identifying structural characteristics unique to each system that can affect specific CI response.

Development of Static Balance Measurement and Correction Compound Platform for Single Blade of Controllable Pitch Propeller

NASA Astrophysics Data System (ADS)

Chao, Zhang; Shijie, Su; Yilin, Yang; Guofu, Wang; Chao, Wang

2017-11-01

Aiming at the static balance of the controllable pitch propeller (CPP), a high efficiency static balance method based on the double-layer structure of the measuring table and gantry robot is adopted to realize the integration of torque measurement and corrected polish for controllable pitch propeller blade. The control system was developed by Microsoft Visual Studio 2015, and a composite platform prototype was developed. Through this prototype, conduct an experiment on the complete process of torque measurement and corrected polish based on a 300kg class controllable pitch propeller blade. The results show that the composite platform can correct the static balance of blade with a correct, efficient and labor-saving operation, and can replace the traditional method on static balance of the blade.

Criteria for structural test

NASA Technical Reports Server (NTRS)

1973-01-01

The results of a study to define criteria and techniques of design, analysis and test which permit the use of a single major structural test article for performing dynamic, fatigue, and static testing are presented. The criteria developed is applicable to both space vehicles and aircraft structures operating in the subsonic or supersonic regime. The feasibility of such an approach was demonstrated by defining test interactions, compatibilities and incompatibilities between the three different types of tests. The results of the study indicate that the single test article concept is feasible with a testing sequence of dynamic test followed by a fatigue and static test.

Acoustic structure and propagation in highly porous, layered, fibrous materials

NASA Technical Reports Server (NTRS)

Lambert, R. F.; Tesar, J. S.

1984-01-01

The acoustic structure and propagation of sound in highly porous, layered, fine fiber materials is examined. Of particular interest is the utilization of the Kozeny number for determining the static flow resistance and the static structure factor based on flow permeability measurements. In this formulation the Kozeny number is a numerical constant independent of volume porosity at high porosities. The other essential parameters are then evaluated employing techniques developed earlier for open cell foams. The attenuation and progressive phase characteristics in bulk samples are measured and compared with predicted values. The agreements on the whole are very satisfactory.

Recent advances in reduction methods for nonlinear problems. [in structural mechanics

NASA Technical Reports Server (NTRS)

Noor, A. K.

1981-01-01

Status and some recent developments in the application of reduction methods to nonlinear structural mechanics problems are summarized. The aspects of reduction methods discussed herein include: (1) selection of basis vectors in nonlinear static and dynamic problems, (2) application of reduction methods in nonlinear static analysis of structures subjected to prescribed edge displacements, and (3) use of reduction methods in conjunction with mixed finite element models. Numerical examples are presented to demonstrate the effectiveness of reduction methods in nonlinear problems. Also, a number of research areas which have high potential for application of reduction methods are identified.

A Progression of Static Equilibrium Laboratory Exercises

ERIC Educational Resources Information Center

Kutzner, Mickey; Kutzner, Andrew

2013-01-01

Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…

GENERAL VIEW LOOKING SOUTH AT THE SATURN I STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW LOOKING SOUTH AT THE SATURN I STATIC TEST STAND. NOTE THE FIRST STAGE OF THE SATURN I ROCKET ON DISPLAY TO THE LEFT OF THE TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

solveTruss v1.0: Static, global buckling and frequency analysis of 2D and 3D trusses with Mathematica

NASA Astrophysics Data System (ADS)

Ozbasaran, Hakan

Trusses have an important place amongst engineering structures due to many advantages such as high structural efficiency, fast assembly and easy maintenance. Iterative truss design procedures, which require analysis of a large number of candidate structural systems such as size, shape and topology optimization with stochastic methods, mostly lead the engineer to establish a link between the development platform and external structural analysis software. By increasing number of structural analyses, this (probably slow-response) link may climb to the top of the list of performance issues. This paper introduces a software for static, global member buckling and frequency analysis of 2D and 3D trusses to overcome this problem for Mathematica users.

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS VIEW SHOWS TWO MAJOR CHANGES TO THE STATIC TEST TOWER: THE ADDITION OF THE NASA LOGO TO THE FACADE AND THE ADDITION OF THE UPPER STAGES TO THE JUPITER MISSILE IN THE WEST POSITION ON THE TOWER TO REPRESENT THE JUNO II CONFIGURATION. 1961, PHOTOGRAPHER UNKNOWN, FRED ORDWAY COLLECTION, U. S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Structural design and static analysis of a double-ring deployable truss for mesh antennas

NASA Astrophysics Data System (ADS)

Xu, Yan; Guan, Fuling; Chen, Jianjun; Zheng, Yao

2012-12-01

This paper addresses the structural design, the deployment control design, the static analysis and the model testing of a new double-ring deployable truss that is intended for large mesh antennas. This deployable truss is a multi-DOF (degree-of-freedom), over-constrained mechanism. Two kinds of deployable basic elements were introduced, as well as a process to synthesise the structure of the deployable truss. The geometric equations were formulated to determine the length of each strut, including the effects of the joint size. A DOF evaluation showed that the mechanism requires two active cables and requires deployment control. An open-loop control system was designed to control the rotational velocities of two motors. The structural stiffness of the truss was assessed by static analysis that considered the effects of the constraint condition and the pre-stress of the passive cables. A 4.2-metre demonstration model of an antenna was designed and fabricated. The geometry and the deployment behaviour of the double-ring truss were validated by the experiments using this model.

A Numerical Study of Automated Dynamic Relaxation for Nonlinear Static Tensioned Structures.

DTIC Science & Technology

1987-10-01

sytem f dscree fnit element equations, i.e., an algebraic system. The form of these equa- tions is the same for all nonlinear kinematic structures that...the first phase the solu- tion to the static, prestress configuration is sought. This phase is also referred to as form finding, shape finding, or the...does facilitate stability of the numerical solution. The system of equations, which is the focus of the solution methods presented, is formed by a

Estimation of Time Dependent Properties from Surface Pressure in Open Cavities

DTIC Science & Technology

2008-02-01

static pressure of the cavity. The stagnation and static pressures are measured separately with Druck Model DPI 145 pressure transducers (with a quoted...interacting with the ZNMF actuator jets, the 2D shape of the vortical structures transform to a 3D shape with spanwise vortical structures. These...Therefore, the pressure gradient in the d direction is dd ° 3d Substituting Equation (5.3) into Equation (5.5) results in ^l = PJk(e^-Re^)/c^ (5.6

Crashworthy airframe design concepts: Fabrication and testing

NASA Technical Reports Server (NTRS)

Cronkhite, J. D.; Berry, V. L.

1982-01-01

Crashworthy floor concepts applicable to general aviation aircraft metal airframe structures were investigated. Initially several energy absorbing lower fuselage structure concepts were evaluated. Full scale floor sections representative of a twin engine, general aviation airplane lower fuselage structure were designed and fabricated. The floors featured an upper high strength platform with an energy absorbing, crushable structure underneath. Eighteen floors were fabricated that incorporated five different crushable subfloor concepts. The floors were then evaluated through static and dynamic testing. Computer programs NASTRAN and KRASH were used for the static and dynamic analysis of the floor section designs. Two twin engine airplane fuselages were modified to incorporate the most promising crashworthy floor sections for test evaluation.

User document for computer programs for ring-stiffened shells of revolution

NASA Technical Reports Server (NTRS)

Cohen, G. A.

1973-01-01

A user manual and related program documentation is presented for six compatible computer programs for structural analysis of axisymmetric shell structures. The programs apply to a common structural model but analyze different modes of structural response. In particular, they are: (1) Linear static response under asymmetric loads; (2) Buckling of linear states under asymmetric loads; (3) Nonlinear static response under axisymmetric loads; (4) Buckling nonlinear states under axisymmetric (5) Imperfection sensitivity of buckling modes under axisymmetric loads; and (6) Vibrations about nonlinear states under axisymmetric loads. These programs treat branched shells of revolution with an arbitrary arrangement of a large number of open branches but with at most one closed branch.

Dynamic Investigation of Static Divergence: Analysis and Testing

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

2000-01-01

The phenomenon known as aeroelastic divergence is the focus of this work. The analyses and experiment presented here show that divergence can occur without a structural dynamic mode losing its oscillatory nature. Aeroelastic divergence occurs when the structural restorative capability or stiffness of a structure is overwhelmed by the static aerodynamic moment. This static aeroelastic coupling does not require the structural dynamic system behavior to cease, however. Aeroelastic changes in the dynamic mode behavior are governed not only by the stiffness, but by damping and inertial properties. The work presented here supports these fundamental assertions by examining a simple system: a typical section airfoil with only a rotational structural degree of freedom. Analytical results identified configurations that exhibit different types of dynamic mode behavior as the system encounters divergence. A wind tunnel model was designed and tested to examine divergence experimentally. The experimental results validate the analytical calculations and explicitly examine the divergence phenomenon where the dynamic mode persists. Three configurations of the wind tunnel model were tested. The experimental results agree very well with the analytical predictions of subcritical characteristics, divergence velocity, and behavior of the noncritical dynamic mode at divergence.

Dynamic and static structure studies of colloidal suspensions with XPCS, SAXS and XNFS

NASA Astrophysics Data System (ADS)

Lu, Xinhui

In the first project, I studied the onset of structural arrest and glass formation in a suspension of silica nanoparticles in a water-lutidine binary mixture near its consolute point using X-ray Photon Correlation Spectroscopy (XPCS) and Small Angle X-ray Scattering (SAXS). I obtained the temperature evolution of the static and dynamic structure, revealing that glass transitions occur both on cooling and on heating, and an unusual logarithmic relaxation within the intermediate liquid between the two glasses, as predicted by mode-coupling theory. In another project, I implemented and exploited the recently-introduced, coherence-based technique of X-ray Near-Field Speckle (XNFS) to characterize the structure and dynamics of micrometer-sized particles. In XNFS, the measured speckles originate from the interference between the incident and scattered beams, and enable truly ultra-small angle x-ray scattering measurements with a simple setup. We built a micrometer-resolution XNFS detector with a high numerical aperture microscope objective and demonstrated its capability of studying static structures and dynamics in longer length scale than traditional far field x-ray techniques by measuring dilute silica and polystyrene samples. We also discussed the limitation of this technique.

Determination of Structural Topology of a Membrane Protein in Lipid -Bilayers using Polarization Optimized Experiments (POE) for Static and MAS Solid State NMR Spectroscopy

PubMed Central

Mote, Kaustubh R.; Gopinath, T.; Veglia, Gianluigi

2013-01-01

The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments (POE), for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD ∼ 0.44 Å, a tilt angle of 24° ± 1°, and an azimuthal angle of 55° ± 6°. This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional O-ssNMR and MAS-ssNMR. PMID:23963722

Fluorescent lamp with static magnetic field generating means

DOEpatents

Moskowitz, Philip E.; Maya, Jakob

1987-01-01

A fluorescent lamp wherein magnetic field generating means (e.g., permanent magnets) are utilized to generate a static magnetic field across the respective electrode structures of the lamp such that maximum field strength is located at the electrode's filament. An increase in efficacy during operation has been observed.

Fluorescent lamp with static magnetic field generating means

DOEpatents

Moskowitz, P.E.; Maya, J.

1987-09-08

A fluorescent lamp wherein magnetic field generating means (e.g., permanent magnets) are utilized to generate a static magnetic field across the respective electrode structures of the lamp such that maximum field strength is located at the electrode's filament. An increase in efficacy during operation has been observed. 2 figs.

Structural modeling of aircraft tires

NASA Technical Reports Server (NTRS)

Clark, S. K.; Dodge, R. N.; Lackey, J. I.; Nybakken, G. H.

1973-01-01

A theoretical and experimental investigation of the feasibility of determining the mechanical properties of aircraft tires from small-scale model tires was accomplished. The theoretical results indicate that the macroscopic static and dynamic mechanical properties of aircraft tires can be accurately determined from the scale model tires although the microscopic and thermal properties of aircraft tires can not. The experimental investigation was conducted on a scale model of a 40 x 12, 14 ply rated, type 7 aircraft tire with a scaling factor of 8.65. The experimental results indicate that the scale model tire exhibited the same static mechanical properties as the prototype tire when compared on a dimensionless basis. The structural modeling concept discussed in this report is believed to be exact for mechanical properties of aircraft tires under static, rolling, and transient conditions.

A Procedure for Modeling Structural Component/Attachment Failure Using Transient Finite Element Analysis

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Jegley, Dawn C. (Technical Monitor)

2007-01-01

Structures often comprise smaller substructures that are connected to each other or attached to the ground by a set of finite connections. Under static loading one or more of these connections may exceed allowable limits and be deemed to fail. Of particular interest is the structural response when a connection is severed (failed) while the structure is under static load. A transient failure analysis procedure was developed by which it is possible to examine the dynamic effects that result from introducing a discrete failure while a structure is under static load. The failure is introduced by replacing a connection load history by a time-dependent load set that removes the connection load at the time of failure. The subsequent transient response is examined to determine the importance of the dynamic effects by comparing the structural response with the appropriate allowables. Additionally, this procedure utilizes a standard finite element transient analysis that is readily available in most commercial software, permitting the study of dynamic failures without the need to purchase software specifically for this purpose. The procedure is developed and explained, demonstrated on a simple cantilever box example, and finally demonstrated on a real-world example, the American Airlines Flight 587 (AA587) vertical tail plane (VTP).

Static heterogeneities in liquid water

NASA Astrophysics Data System (ADS)

Stanley, H. Eugene; Buldyrev, Sergey V.; Giovambattista, Nicolas

2004-10-01

The thermodynamic behavior of water seems to be closely related to static heterogeneities. These static heterogeneities are related to the local structure of water molecules, and when properly characterized, may offer an economical explanation of thermodynamic data. The key feature of liquid water is not so much that the existence of hydrogen bonds, first pointed out by Linus Pauling, but rather the local geometry of the liquid molecules is not spherical or oblong but tetrahedral. In the consideration of static heterogeneities, this local geometry is critical. Recent experiments suggested more than one phase of amorphous solid water, while simulations suggest that one of these phases is metastable with respect to another, so that in fact there are only two stable phases.

Pheromone Static Routing Strategy for Complex Networks

NASA Astrophysics Data System (ADS)

Hu, Mao-Bin; Henry, Y. K. Lau; Ling, Xiang; Jiang, Rui

2012-12-01

We adopt the concept of using pheromones to generate a set of static paths that can reach the performance of global dynamic routing strategy [Phys. Rev. E 81 (2010) 016113]. The path generation method consists of two stages. In the first stage, a pheromone is dropped to the nodes by packets forwarded according to the global dynamic routing strategy. In the second stage, pheromone static paths are generated according to the pheromone density. The output paths can greatly improve traffic systems' overall capacity on different network structures, including scale-free networks, small-world networks and random graphs. Because the paths are static, the system needs much less computational resources than the global dynamic routing strategy.

Non-crossbridge calcium-dependent stiffness in slow and fast skeletal fibres from mouse muscle.

PubMed

Nocella, Marta; Colombini, Barbara; Bagni, Maria Angela; Bruton, Joseph; Cecchi, Giovanni

2012-03-01

We showed previously that force development in frog and FDB mouse skeletal muscle fibres is preceded by an increase of fibre stiffness occurring well before crossbridge attachment and force generation. This stiffness increase, referred to as static stiffness, is due to a Ca(2+)-dependent stiffening of a non-crossbridge sarcomere structure which we suggested could be attributed to the titin filaments. To investigate further the role of titin in static stiffness, we measured static stiffness properties at 24 and 35°C in soleus and EDL mouse muscle fibres which are known to express different titin isoforms. We found that static stiffness was present in both soleus and EDL fibres, however, its value was about five times greater in EDL than in soleus fibres. The rate of development of static stiffness on stimulation increased with temperature and was slightly faster in EDL than in soleus in agreement with previously published data on the time course of the intracellular Ca(2+) transients in these muscles. The present results show that the presence of a non-crossbridge Ca(2+)-dependent stiffening of the muscle fibre is a physiological general characteristic of skeletal muscle. Static stiffness depends on fibre type, being greater and developing faster in fast than in slow fibres. Our observations are consistent with the idea that titin stiffening on contraction improves the sarcomere structure stability. Such an action in fact seems to be more important in EDL fast fibre than in soleus slow fibres.

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed Central

Schröter, Tobias J.; Johnson, Shane B.; John, Kerstin; Santi, Peter A.

2011-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. PMID:22254177

Resolution of structural heterogeneity in dynamic crystallography

PubMed Central

Ren, Zhong; Chan, Peter W. Y.; Moffat, Keith; Pai, Emil F.; Royer, William E.; Šrajer, Vukica; Yang, Xiaojing

2013-01-01

Dynamic behavior of proteins is critical to their function. X-­ray crystallography, a powerful yet mostly static technique, faces inherent challenges in acquiring dynamic information despite decades of effort. Dynamic ‘structural changes’ are often indirectly inferred from ‘structural differences’ by comparing related static structures. In contrast, the direct observation of dynamic structural changes requires the initiation of a biochemical reaction or process in a crystal. Both the direct and the indirect approaches share a common challenge in analysis: how to interpret the structural heterogeneity intrinsic to all dynamic processes. This paper presents a real-space approach to this challenge, in which a suite of analytical methods and tools to identify and refine the mixed structural species present in multiple crystallographic data sets have been developed. These methods have been applied to representative scenarios in dynamic crystallography, and reveal structural information that is otherwise difficult to interpret or inaccessible using conventional methods. PMID:23695239

Resolution of structural heterogeneity in dynamic crystallography.

PubMed

Ren, Zhong; Chan, Peter W Y; Moffat, Keith; Pai, Emil F; Royer, William E; Šrajer, Vukica; Yang, Xiaojing

2013-06-01

Dynamic behavior of proteins is critical to their function. X-ray crystallography, a powerful yet mostly static technique, faces inherent challenges in acquiring dynamic information despite decades of effort. Dynamic `structural changes' are often indirectly inferred from `structural differences' by comparing related static structures. In contrast, the direct observation of dynamic structural changes requires the initiation of a biochemical reaction or process in a crystal. Both the direct and the indirect approaches share a common challenge in analysis: how to interpret the structural heterogeneity intrinsic to all dynamic processes. This paper presents a real-space approach to this challenge, in which a suite of analytical methods and tools to identify and refine the mixed structural species present in multiple crystallographic data sets have been developed. These methods have been applied to representative scenarios in dynamic crystallography, and reveal structural information that is otherwise difficult to interpret or inaccessible using conventional methods.

Control of Flexible Structures (COFS) Flight Experiment Background and Description

NASA Technical Reports Server (NTRS)

Hanks, B. R.

1985-01-01

A fundamental problem in designing and delivering large space structures to orbit is to provide sufficient structural stiffness and static configuration precision to meet performance requirements. These requirements are directly related to control requirements and the degree of control system sophistication available to supplement the as-built structure. Background and rationale are presented for a research study in structures, structural dynamics, and controls using a relatively large, flexible beam as a focus. This experiment would address fundamental problems applicable to large, flexible space structures in general and would involve a combination of ground tests, flight behavior prediction, and instrumented orbital tests. Intended to be multidisciplinary but basic within each discipline, the experiment should provide improved understanding and confidence in making design trades between structural conservatism and control system sophistication for meeting static shape and dynamic response/stability requirements. Quantitative results should be obtained for use in improving the validity of ground tests for verifying flight performance analyses.

Synovial fibroblasts self-direct multicellular lining architecture and synthetic function in three-dimensional organ culture.

PubMed

Kiener, Hans P; Watts, Gerald F M; Cui, Yajun; Wright, John; Thornhill, Thomas S; Sköld, Markus; Behar, Samuel M; Niederreiter, Birgit; Lu, Jun; Cernadas, Manuela; Coyle, Anthony J; Sims, Gary P; Smolen, Josef; Warman, Matthew L; Brenner, Michael B; Lee, David M

2010-03-01

To define the intrinsic capacity of fibroblast-like synoviocytes (FLS) to establish a 3-dimensional (3-D) complex synovial lining architecture characterized by the multicellular organization of the compacted synovial lining and the elaboration of synovial fluid constituents. FLS were cultured in spherical extracellular matrix (ECM) micromasses for 3 weeks. The FLS micromass architecture was assessed histologically and compared with that of dermal fibroblast controls. Lubricin synthesis was measured via immunodetection. Basement membrane matrix and reticular fiber stains were performed to examine ECM organization. Primary human and mouse monocytes were prepared and cocultured with FLS in micromass to investigate cocompaction in the lining architecture. Cytokine stimuli were applied to determine the capacity for inflammatory architecture rearrangement. FLS, but not dermal fibroblasts, spontaneously formed a compacted lining architecture over 3 weeks in the 3-D ECM micromass organ cultures. These lining cells produced lubricin. FLS rearranged their surrounding ECM into a complex architecture resembling the synovial lining and supported the survival and cocompaction of monocyte/macrophages in the neo-lining structure. Furthermore, when stimulated by cytokines, FLS lining structures displayed features of the hyperplastic rheumatoid arthritis synovial lining. This 3-D micromass organ culture method demonstrates that many of the phenotypic characteristics of the normal and the hyperplastic synovial lining in vivo are intrinsic functions of FLS. Moreover, FLS promote survival and cocompaction of primary monocytes in a manner remarkably similar to that of synovial lining macrophages. These findings provide new insight into inherent functions of the FLS lineage and establish a powerful in vitro method for further investigation of this lineage.

A comparative study of the microstructures observed in statically cast and continuously cast Bi-In-Sn ternary eutectic alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sengupta, S.; Soda, H.; McLean, A.

2000-01-01

A ternary eutectic alloy with a composition of 57.2 pct Bi, 24.8 pct In, and 18 pct Sn was continuously cast into wire of 2 mm diameter with casting speeds of 14 and 79 mm/min using the Ohno Continuous Casting (OCC) process. The microstructures obtained were compared with those of statically cast specimens. Extensive segregation of massive Bi blocks, Bi complex structures, and tin-rich dendrites was found in specimens that were statically cast. Decomposition of {radical}Sn by a eutectoid reaction was confirmed based on microstructural evidence. Ternary eutectic alloy with a cooling rate of approximately 1 C/min formed a doublemore » binary eutectic. The double binary eutectic consisted of regions of BiIn and decomposed {radical}Sn in the form of a dendrite cell structure and regions of Bi and decomposed {radical}Sn in the form of a complex-regular cell. The Bi complex-regular cells, which are a ternary eutectic constituent, existed either along the boundaries of the BiIn-decomposed {radical}Sn dendrite cells or at the front of elongated dendrite cell structures. In the continuously cast wires, primary Sn dendrites coupled with a small Bi phase were uniformly distributed within the Bi-In alloy matrix. Neither massive Bi phase, Bi complex-regular cells, no BiIn eutectic dendrite cells were observed, resulting in a more uniform microstructure in contrast to the heavily segregated structures of the statically cast specimens.« less

Refraction traveltime tomography based on damped wave equation for irregular topographic model

NASA Astrophysics Data System (ADS)

Park, Yunhui; Pyun, Sukjoon

2018-03-01

Land seismic data generally have time-static issues due to irregular topography and weathered layers at shallow depths. Unless the time static is handled appropriately, interpretation of the subsurface structures can be easily distorted. Therefore, static corrections are commonly applied to land seismic data. The near-surface velocity, which is required for static corrections, can be inferred from first-arrival traveltime tomography, which must consider the irregular topography, as the land seismic data are generally obtained in irregular topography. This paper proposes a refraction traveltime tomography technique that is applicable to an irregular topographic model. This technique uses unstructured meshes to express an irregular topography, and traveltimes calculated from the frequency-domain damped wavefields using the finite element method. The diagonal elements of the approximate Hessian matrix were adopted for preconditioning, and the principle of reciprocity was introduced to efficiently calculate the Fréchet derivative. We also included regularization to resolve the ill-posed inverse problem, and used the nonlinear conjugate gradient method to solve the inverse problem. As the damped wavefields were used, there were no issues associated with artificial reflections caused by unstructured meshes. In addition, the shadow zone problem could be circumvented because this method is based on the exact wave equation, which does not require a high-frequency assumption. Furthermore, the proposed method was both robust to an initial velocity model and efficient compared to full wavefield inversions. Through synthetic and field data examples, our method was shown to successfully reconstruct shallow velocity structures. To verify our method, static corrections were roughly applied to the field data using the estimated near-surface velocity. By comparing common shot gathers and stack sections with and without static corrections, we confirmed that the proposed tomography algorithm can be used to correct the statics of land seismic data.

Structural Influence on the Mechanical Response of Adolescent Gottingen Porcine Cranial Bone

DTIC Science & Technology

2016-10-01

specimens were then loaded in quasi -static compression to measure their mechanical response. The surface strain distribution on the specimen face was...13 Fig. 10 Apparent stress-strain responses of a sample of specimens loaded in quasi -static compression...modulus-BVF experimental results shown in Fig. 15 ..................................................................................19 Fig. 17 The

30 CFR 784.16 - Reclamation plan: Siltation structures, impoundments, and refuse piles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Resources Conservation Service's Web site athttp://www.info.usda.gov/scripts/lpsiis.dll/TR/TR_210_60.htm... State program approval process engineering design standards that ensure stability comparable to a 1.3 minimum static safety factor in lieu of engineering tests to establish compliance with the minimum static...

33. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER DURING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER DURING A TEST OF THE PROPULSION SYSTEM OF A JUPITER MISSILE. DATE AND PHOTOGRAPHER UNKNOWN. FRED ORDWAY COLLECTION, U.S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Laboratory and field performance of FOS sensors in static and dynamic strain monitoring in concrete bridge decks

NASA Astrophysics Data System (ADS)

Benmokrane, B.; Debaiky, A.; El-Ragaby, A.; Roy, R.; El-Gamal, S.; El-Salakawy, E.

2006-03-01

There is a growing need for designing and constructing innovative concrete bridges using FRP reinforcing bars as internal reinforcement to avoid the corrosion problems and high costs of maintenance and repair. For efficient use and to increase the lifetime of these bridges, it is important to develop efficient monitoring systems for such innovative structures. Fabry-Perot and Bragg fibre optic sensors (FOS) that can measure the strains and temperature are promising candidates for life-long health monitoring of these structures. This article reports laboratory and field performance of Fabry-Perot and Bragg FOS sensors as well as electrical strain gauges in static and dynamic strain monitoring in concrete bridge decks. The laboratory tests include tensile testing of glass FRP bars and testing of full-scale concrete bridge deck slabs reinforced with glass and carbon FRP bars under static and cyclic concentrated loads. The field tests include static and dynamic testing of two bridges reinforced with steel and glass FRP bars. The obtained strain results showed satisfactory agreement between the different gauges.

A minimalistic approach to static and dynamic electron correlations: Amending generalized valence bond method with extended random phase approximation correlation correction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatterjee, Koushik; Jawulski, Konrad; Pastorczak, Ewa

A perfect-pairing generalized valence bond (GVB) approximation is known to be one of the simplest approximations, which allows one to capture the essence of static correlation in molecular systems. In spite of its attractive feature of being relatively computationally efficient, this approximation misses a large portion of dynamic correlation and does not offer sufficient accuracy to be generally useful for studying electronic structure of molecules. We propose to correct the GVB model and alleviate some of its deficiencies by amending it with the correlation energy correction derived from the recently formulated extended random phase approximation (ERPA). On the examples ofmore » systems of diverse electronic structures, we show that the resulting ERPA-GVB method greatly improves upon the GVB model. ERPA-GVB recovers most of the electron correlation and it yields energy barrier heights of excellent accuracy. Thanks to a balanced treatment of static and dynamic correlation, ERPA-GVB stays reliable when one moves from systems dominated by dynamic electron correlation to those for which the static correlation comes into play.« less

Study of Geometric Porosity on Static Stability and Drag Using Computational Fluid Dynamics for Rigid Parachute Shapes

NASA Technical Reports Server (NTRS)

Greathouse, James S.; Schwing, Alan M.

2015-01-01

This paper explores use of computational fluid dynamics to study the e?ect of geometric porosity on static stability and drag for NASA's Multi-Purpose Crew Vehicle main parachute. Both of these aerodynamic characteristics are of interest to in parachute design, and computational methods promise designers the ability to perform detailed parametric studies and other design iterations with a level of control previously unobtainable using ground or flight testing. The approach presented here uses a canopy structural analysis code to define the inflated parachute shapes on which structured computational grids are generated. These grids are used by the computational fluid dynamics code OVERFLOW and are modeled as rigid, impermeable bodies for this analysis. Comparisons to Apollo drop test data is shown as preliminary validation of the technique. Results include several parametric sweeps through design variables in order to better understand the trade between static stability and drag. Finally, designs that maximize static stability with a minimal loss in drag are suggested for further study in subscale ground and flight testing.

Structural characterization of a first-generation articulated-truss joint for space crane application

NASA Technical Reports Server (NTRS)

Sutter, Thomas R.; Wu, K. Chauncey; Riutort, Kevin T.; Laufer, Joseph B.; Phelps, James E.

1992-01-01

A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection response is also presented for one of the linear actuators used in the articulated-truss joint. Finally, an assessment is presented for the predictability of the truss hardware used in the reference truss and articulated-truss joint based upon hardware stiffness properties that were previously obtained during the Precision Segmented Reflector (PSR) Technology Development Program.

ER Stress: A Therapeutic Target in Rheumatoid Arthritis?

PubMed

Rahmati, Marveh; Moosavi, Mohammad Amin; McDermott, Michael F

2018-04-22

Diverse physiological and pathological conditions that impact on protein folding of the endoplasmic reticulum (ER) cause ER stress. The unfolded protein response (UPR) and the ER-associated degradation (ERAD) pathway are activated to cope with ER stress. In rheumatoid arthritis (RA), inflammation and ER stress work in parallel by driving inflammatory cells to release cytokines that induce chronic ER stress pathways. This chronic ER stress may contribute to the pathogenesis of RA through synoviocyte proliferation and proinflammatory cytokine production. Therefore, ER stress pathways and their constituent elements are attractive targets for RA drug development. In this review, we integrate current knowledge of the contribution of ER stress to the overall pathogenesis of RA, and suggest some therapeutic implications of these discoveries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Homogentisate 1,2 Dioxygenase is Expressed in Human Osteoarticular Cells: Implications in Alkaptonuria

PubMed Central

Laschi, Marcella; Tinti, Laura; Braconi, Daniela; Millucci, Lia; Ghezzi, Lorenzo; Amato, Loredana; Selvi, Enrico; Spreafico, Adriano; Bernardini, Giulia; Santucci, Annalisa

2012-01-01

Alkaptonuria (AKU) results from defective homogentisate1,2-dioxygenase (HGD), causing degenerative arthropathy. The deposition of ochronotic pigment in joints is so far attributed to homogentisic acid produced by the liver, circulating in the blood and accumulating locally. Human normal and AKU osteoarticular cells were tested for HGD gene expression by RT-PCR, mono- and 2D-Western blotting. HGD gene expression was revealed in chondrocytes, synoviocytes, osteoblasts. Furthermore, HGD expression was confirmed by Western blotting, that also revealed the presence of five enzymatic molecular species. Our findings indicate that AKU osteoarticular cells produce the ochronotic pigment in loco and this may strongly contribute to induction of ochronotic arthropathy. J. Cell. Physiol. 227: 3254–3257, 2012. © 2011 Wiley Periodicals, Inc. PMID:22105303

Stable static structures in models with higher-order derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bazeia, D., E-mail: bazeia@fisica.ufpb.br; Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB; Lobão, A.S.

2015-09-15

We investigate the presence of static solutions in generalized models described by a real scalar field in four-dimensional space–time. We study models in which the scalar field engenders higher-order derivatives and spontaneous symmetry breaking, inducing the presence of domain walls. Despite the presence of higher-order derivatives, the models keep to equations of motion second-order differential equations, so we focus on the presence of first-order equations that help us to obtain analytical solutions and investigate linear stability on general grounds. We then illustrate the general results with some specific examples, showing that the domain wall may become compact and that themore » zero mode may split. Moreover, if the model is further generalized to include k-field behavior, it may contribute to split the static structure itself.« less

An ab initio study of the structure and dynamics of bulk liquid Ag and its liquid-vapor interface

NASA Astrophysics Data System (ADS)

Gonzalez Del Rio, Beatriz; Gonzalez Tesedo, Luis Enrique; Gonzalez Fernandez, David Jose

Several static and dynamic properties of bulk liquid Ag at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation which points to a small positive dispersion. Results are also reported at a slightly higher temperature in order to study the structure of the free liquid surface. The ionic density profile shows an oscillatory behaviour with two different wavelenghts, as the spacing between the outer and first inner layer is different from that between the other inner layers.

The acoustical structure of highly porous open-cell foams

NASA Technical Reports Server (NTRS)

Lambert, R. F.

1982-01-01

This work concerns both the theoretical prediction and measurement of structural parameters in open-cell highly porous polyurethane foams. Of particular interest are the dynamic flow resistance, thermal time constant, and mass structure factor and their dependence on frequency and geometry of the cellular structure. The predictions of cell size parameters, static flow resistance, and heat transfer as accounted for by a Nusselt number are compared with measurement. Since the static flow resistance and inverse thermal time constant are interrelated via the 'mean' pore size parameter of Biot, only two independent measurements such as volume porosity and mean filament diameter are required to make the predictions for a given fluid condition. The agreements between this theory and nonacoustical experiments are excellent.

Ab-initio study of several static and dynamic properties of liquid palladium and platinum

NASA Astrophysics Data System (ADS)

González, L. E.; González, D. J.; Molla, Mohammad Riazuddin; Ahmed, A. Z. Ziauddin; Bhuiyan, G. M.

2017-08-01

We report a study on several static and dynamic properties of liquid Pd and Pt metals at thermodynamic conditions near their respective triple points. The calculations have been carried out by an ab initio molecular dynamics simulation technique. Results are reported for several static structural magnitudes which are compared with the available X-ray diffraction. As for the dynamic properties, results have been obtained for both single and collective dynamical magnitudes as well as for some transport coeffcients which are compared with the corresponding experimental data.

Static and dynamic strain energy release rates in toughened thermosetting composite laminates

NASA Technical Reports Server (NTRS)

Cairns, Douglas S.

1992-01-01

In this work, the static and dynamic fracture properties of several thermosetting resin based composite laminates are presented. Two classes of materials are explored. These are homogeneous, thermosetting resins and toughened, multi-phase, thermosetting resin systems. Multi-phase resin materials have shown enhancement over homogenous materials with respect to damage resistance. The development of new dynamic tests are presented for composite laminates based on Width Tapered Double Cantilevered Beam (WTDCB) for Mode 1 fracture and the End Notched Flexure (ENF) specimen. The WTDCB sample was loaded via a low inertia, pneumatic cylinder to produce rapid cross-head displacements. A high rate, piezo-electric load cell and an accelerometer were mounted on the specimen. A digital oscilloscope was used for data acquisition. Typical static and dynamic load versus displacement plots are presented. The ENF specimen was impacted in three point bending with an instrumented impact tower. Fracture initiation and propagation energies under static and dynamic conditions were determined analytically and experimentally. The test results for Mode 1 fracture are relatively insensitive to strain rate effects for the laminates tested in this study. The test results from Mode 2 fracture indicate that the toughened systems provide superior fracture initiation and higher resistance to propagation under dynamic conditions. While the static fracture properties of the homogeneous systems may be relatively high, the apparent Mode 2 dynamic critical strain energy release rate drops significantly. The results indicate that static Mode 2 fracture testing is inadequate for determining the fracture performance of composite structures subjected to conditions such as low velocity impact. A good correlation between the basic Mode 2 dynamic fracture properties and the performance is a combined material/structural Compression After Impact (CAI) test is found. These results underscore the importance of examining rate-dependent behavior for determining the longevity of structures manufactured from composite materials.

Static and dynamic stability analysis of the space shuttle vehicle-orbiter

NASA Technical Reports Server (NTRS)

Chyu, W. J.; Cavin, R. K.; Erickson, L. L.

1978-01-01

The longitudinal static and dynamic stability of a Space Shuttle Vehicle-Orbiter (SSV Orbiter) model is analyzed using the FLEXSTAB computer program. Nonlinear effects are accounted for by application of a correction technique in the FLEXSTAB system; the technique incorporates experimental force and pressure data into the linear aerodynamic theory. A flexible Orbiter model is treated in the static stability analysis for the flight conditions of Mach number 0.9 for rectilinear flight (1 g) and for a pull-up maneuver (2.5 g) at an altitude of 15.24 km. Static stability parameters and structural deformations of the Orbiter are calculated at trim conditions for the dynamic stability analysis, and the characteristics of damping in pitch are investigated for a Mach number range of 0.3 to 1.2. The calculated results for both the static and dynamic stabilities are compared with the available experimental data.

Study of the influence of hole quality on composite materials

NASA Technical Reports Server (NTRS)

Pengra, J. J.

1980-01-01

The influence of hole quality on the structural behavior of composite materials was investigated. From an industry survey it was determined that the most frequent imperfections encountered during hole fabrication are chipout, delamination, and oversize conditions. These hole flaw types were generated in critical areas of static, compression, and fatigue specimens fabricated from T300/5208 graphite/epoxy system. The specimens were tested in static and cyclic pin bearing modes in addition to compression loading. Results of these tests are presented and discussed. The hole chipout defect reduced the static and cyclic endurance characteristics. Oversize holes also lowered the cyclic pin bearing endurance, but had no influence of the static pin bearing characteristics. Delamination had no insignificant influence on the static tension and cyclic pin bearing characteristics. Compression tests demonstrated a deleterious effect for chipout of delamination defects. Hole quality requirements proposed are discussed.

Residual strength and crack propagation tests on C-130 airplane center wings with service-imposed fatigue damage

NASA Technical Reports Server (NTRS)

Snider, H. L.; Reeder, F. L.; Dirkin, W. J.

1972-01-01

Fourteen C-130 airplane center wings, each containing service-imposed fatigue damage resulting from 4000 to 13,000 accumulated flight hours, were tested to determine their fatigue crack propagation and static residual strength characteristics. Eight wings were subjected to a two-step constant amplitude fatigue test prior to static testing. Cracks up to 30 inches long were generated in these tests. Residual static strengths of these wings ranged from 56 to 87 percent of limit load. The remaining six wings containing cracks up to 4 inches long were statically tested as received from field service. Residual static strengths of these wings ranged from 98 to 117 percent of limit load. Damage-tolerant structural design features such as fastener holes, stringers, doublers around door cutouts, and spanwise panel splices proved to be effective in retarding crack propagation.

Reduction in static friction by deposition of a homogeneous diamond-like carbon (DLC) coating on orthodontic brackets.

PubMed

Akaike, Shun; Hayakawa, Tohru; Kobayashi, Daishiro; Aono, Yuko; Hirata, Atsushi; Hiratsuka, Masanori; Nakamura, Yoshiki

2015-01-01

In orthodontics, a reduction in static friction between the brackets and wire is important to enable easy tooth movement. The aim of this study was to examine the effects of a homogeneous diamond-like carbon (DLC) coating on the whole surfaces of slots in stainless steel orthodontic brackets on reducing the static friction between the brackets and the wire. The DLC coating was characterized using Raman spectroscopy, surface roughness and contact angle measurements, and SEM observations. Rectangular stainless steel and titanium-molybdenum alloy wires with two different sizes were employed, and the static friction between the brackets and wire was measured under dry and wet conditions. The DLC coating had a thickness of approximately 1.0 μm and an amorphous structure was identified. The results indicated that the DLC coating always led to a reduction in static friction.

NASA LeRC/Akron University Graduate Cooperative Fellowship Program and Graduate Student Researchers Program

NASA Technical Reports Server (NTRS)

Fertis, D. G.; Simon, A. L.

1981-01-01

The requisite methodology to solve linear and nonlinear problems associated with the static and dynamic analysis of rotating machinery, their static and dynamic behavior, and the interaction between the rotating and nonrotating parts of an engine is developed. Linear and nonlinear structural engine problems are investigated by developing solution strategies and interactive computational methods whereby the man and computer can communicate directly in making analysis decisions. Representative examples include modifying structural models, changing material, parameters, selecting analysis options and coupling with interactive graphical display for pre- and postprocessing capability.

A nonlinear auxetic structural vibration damper with metal rubber particles

NASA Astrophysics Data System (ADS)

Ma, Yanhong; Scarpa, Fabrizio; Zhang, Dayi; Zhu, Bin; Chen, Lulu; Hong, Jie

2013-08-01

The work describes the mechanical performance of a metal rubber particles (MRP) damper design based on an auxetic (negative Poisson’s ratio) cellular configuration. The auxetic damper configuration is constituted by an anti-tetrachiral honeycomb, where the cylinders are filled with the MRP material. The MRP samples have been subjected to quasi-static loading to measure the stiffness and loss factor from the static hysteresis curve. A parametric experimental analysis has been carried out to investigate the effect of relative density and filling percentage on the static performance of the MRP, and to identify design guidelines for best use of MRP devices. An experimental assessment of the integrated auxetic-MRP damper concept has been provided through static and dynamic force response techniques.

Shape effect of ultrafine-grained structure on static fracture toughness in low-alloy steel.

PubMed

Inoue, Tadanobu; Kimura, Yuuji; Ochiai, Shojiro

2012-06-01

A 0.4C-2Si-1Cr-1Mo steel with an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 773 K and subsequent annealing at 973 K. A static three-point bending test was conducted at ambient temperature and at 77 K. The strength-toughness balance of the developed steels was markedly better than that of conventionally quenched and tempered steel with a martensitic structure. In particular, the static fracture toughness of the UFEG steel, having a yield strength of 1.86 GPa at ambient temperature, was improved by more than 40 times compared with conventional steel having a yield strength of 1.51 GPa. Furthermore, even at 77 K, the fracture toughness of the UFEG steel was about eight times higher than that of the conventional and UFG steels, despite the high strength of the UFEG steel (2.26 GPa). The UFG steel exhibited brittle fracture behavior at 77 K, as did the conventional steel, and no dimple structure was observed on the fracture surface. Therefore, it is difficult to improve the low-temperature toughness of the UFG steel by grain refinement only. The shape of crystal grains plays an important role in delamination toughening, as do their refinement and orientation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caliandro, Rocco; Sibillano, Teresa; Belviso, B. Danilo

In this study, we have developed a general X-ray powder diffraction (XPD) methodology for the simultaneous structural and compositional characterization of inorganic nanomaterials. The approach is validated on colloidal tungsten oxide nanocrystals (WO 3-x NCs), as a model polymorphic nanoscale material system. Rod-shaped WO 3-x NCs with different crystal structure and stoichiometry are comparatively investigated under an inert atmosphere and after prolonged air exposure. An initial structural model for the as-synthesized NCs is preliminarily identified by means of Rietveld analysis against several reference crystal phases, followed by atomic pair distribution function (PDF) refinement of the best-matching candidates (static analysis). Subtlemore » stoichiometry deviations from the corresponding bulk standards are revealed. NCs exposed to air at room temperature are monitored by XPD measurements at scheduled time intervals. The static PDF analysis is complemented with an investigation into the evolution of the WO 3-x NC structure, performed by applying the modulation enhanced diffraction technique to the whole time series of XPD profiles (dynamical analysis). Prolonged contact with ambient air is found to cause an appreciable increase in the static disorder of the O atoms in the WO 3-x NC lattice, rather than a variation in stoichiometry. Finally, the time behavior of such structural change is identified on the basis of multivariate analysis.« less

Shape effect of ultrafine-grained structure on static fracture toughness in low-alloy steel

PubMed Central

Inoue, Tadanobu; Kimura, Yuuji; Ochiai, Shojiro

2012-01-01

A 0.4C-2Si-1Cr-1Mo steel with an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 773 K and subsequent annealing at 973 K. A static three-point bending test was conducted at ambient temperature and at 77 K. The strength–toughness balance of the developed steels was markedly better than that of conventionally quenched and tempered steel with a martensitic structure. In particular, the static fracture toughness of the UFEG steel, having a yield strength of 1.86 GPa at ambient temperature, was improved by more than 40 times compared with conventional steel having a yield strength of 1.51 GPa. Furthermore, even at 77 K, the fracture toughness of the UFEG steel was about eight times higher than that of the conventional and UFG steels, despite the high strength of the UFEG steel (2.26 GPa). The UFG steel exhibited brittle fracture behavior at 77 K, as did the conventional steel, and no dimple structure was observed on the fracture surface. Therefore, it is difficult to improve the low-temperature toughness of the UFG steel by grain refinement only. The shape of crystal grains plays an important role in delamination toughening, as do their refinement and orientation. PMID:27877493

Static network structure can stabilize human cooperation.

PubMed

Rand, David G; Nowak, Martin A; Fowler, James H; Christakis, Nicholas A

2014-12-02

The evolution of cooperation in network-structured populations has been a major focus of theoretical work in recent years. When players are embedded in fixed networks, cooperators are more likely to interact with, and benefit from, other cooperators. In theory, this clustering can foster cooperation on fixed networks under certain circumstances. Laboratory experiments with humans, however, have thus far found no evidence that fixed network structure actually promotes cooperation. Here, we provide such evidence and help to explain why others failed to find it. First, we show that static networks can lead to a stable high level of cooperation, outperforming well-mixed populations. We then systematically vary the benefit that cooperating provides to one's neighbors relative to the cost required to cooperate (b/c), as well as the average number of neighbors in the network (k). When b/c > k, we observe high and stable levels of cooperation. Conversely, when b/c ≤ k or players are randomly shuffled, cooperation decays. Our results are consistent with a quantitative evolutionary game theoretic prediction for when cooperation should succeed on networks and, for the first time to our knowledge, provide an experimental demonstration of the power of static network structure for stabilizing human cooperation.

Static network structure can stabilize human cooperation

PubMed Central

Rand, David G.; Nowak, Martin A.; Fowler, James H.; Christakis, Nicholas A.

2014-01-01

The evolution of cooperation in network-structured populations has been a major focus of theoretical work in recent years. When players are embedded in fixed networks, cooperators are more likely to interact with, and benefit from, other cooperators. In theory, this clustering can foster cooperation on fixed networks under certain circumstances. Laboratory experiments with humans, however, have thus far found no evidence that fixed network structure actually promotes cooperation. Here, we provide such evidence and help to explain why others failed to find it. First, we show that static networks can lead to a stable high level of cooperation, outperforming well-mixed populations. We then systematically vary the benefit that cooperating provides to one’s neighbors relative to the cost required to cooperate (b/c), as well as the average number of neighbors in the network (k). When b/c > k, we observe high and stable levels of cooperation. Conversely, when b/c ≤ k or players are randomly shuffled, cooperation decays. Our results are consistent with a quantitative evolutionary game theoretic prediction for when cooperation should succeed on networks and, for the first time to our knowledge, provide an experimental demonstration of the power of static network structure for stabilizing human cooperation. PMID:25404308

Effect of 3-D viscoelastic structure on post-seismic relaxation from the 2004 M = 9.2 Sumatra earthquake

USGS Publications Warehouse

Pollitz, F.; Banerjee, P.; Grijalva, K.; Nagarajan, B.; Burgmann, R.

2008-01-01

The 2004 M=9.2 Sumatra-Andaman earthquake profoundly altered the state of stress in a large volume surrounding the ???1400 km long rupture. Induced mantle flow fields and coupled surface deformation are sensitive to the 3-D rheology structure. To predict the post-seismic motions from this earthquake, relaxation of a 3-D spherical viscoelastic earth model is simulated using the theory of coupled normal modes. The quasi-static deformation basis set and solution on the 3-D model is constructed using: a spherically stratified viscoelastic earth model with a linear stress-strain relation; an aspherical perturbation in viscoelastic structure; a 'static'mode basis set consisting of Earth's spheroidal and toroidal free oscillations; a "viscoelastic" mode basis set; and interaction kernels that describe the coupling among viscoelastic and static modes. Application to the 2004 Sumatra-Andaman earthquake illustrates the profound modification of the post-seismic flow field at depth by a slab structure and similarly large effects on the near-field post-seismic deformation field at Earth's surface. Comparison with post-seismic GPS observations illustrates the extent to which viscoelastic relaxation contributes to the regional post-seismic deformation. ?? Journal compilation ?? 2008 RAS.

The influence of computational assumptions on analysing abdominal aortic aneurysm haemodynamics.

PubMed

Ene, Florentina; Delassus, Patrick; Morris, Liam

2014-08-01

The variation in computational assumptions for analysing abdominal aortic aneurysm haemodynamics can influence the desired output results and computational cost. Such assumptions for abdominal aortic aneurysm modelling include static/transient pressures, steady/transient flows and rigid/compliant walls. Six computational methods and these various assumptions were simulated and compared within a realistic abdominal aortic aneurysm model with and without intraluminal thrombus. A full transient fluid-structure interaction was required to analyse the flow patterns within the compliant abdominal aortic aneurysms models. Rigid wall computational fluid dynamics overestimates the velocity magnitude by as much as 40%-65% and the wall shear stress by 30%-50%. These differences were attributed to the deforming walls which reduced the outlet volumetric flow rate for the transient fluid-structure interaction during the majority of the systolic phase. Static finite element analysis accurately approximates the deformations and von Mises stresses when compared with transient fluid-structure interaction. Simplifying the modelling complexity reduces the computational cost significantly. In conclusion, the deformation and von Mises stress can be approximately found by static finite element analysis, while for compliant models a full transient fluid-structure interaction analysis is required for acquiring the fluid flow phenomenon. © IMechE 2014.

Local Nash equilibrium in social networks.

PubMed

Zhang, Yichao; Aziz-Alaoui, M A; Bertelle, Cyrille; Guan, Jihong

2014-08-29

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.

Local Nash Equilibrium in Social Networks

PubMed Central

Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

2014-01-01

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures. PMID:25169150

Local Nash Equilibrium in Social Networks

NASA Astrophysics Data System (ADS)

Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

2014-08-01

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.

Organic Xenobiotics

NASA Astrophysics Data System (ADS)

Coleman, William F.

2005-02-01

Fully manipulable (Chime) versions of these molecules appear below. These and other molecules are available at Only@ JCE Online . Figure 1. Atrazine molecule. Interactive Chime-based structure (top); static structure graphic (bottom).

Evaluation of engineering plastic for rollover protective structure (ROPS) mounting.

PubMed

Comer, R S; Ayers, P D; Liu, J

2007-04-01

Agriculture has one of the highest fatality rates of any industry in America. Tractor rollovers are a significant contributor to the high death rate. Rollover protective structures (ROPS) have helped lower these high fatality rates on full-size tractors. However, a large number of older tractors still do not use ROPS due to the difficulty of designing and creating a mounting structure. To help reduce this difficulty, engineering plastics were evaluated for use in a ROPS mounting structure on older tractors. The use of engineering plastics around axle housings could provide a uniform mounting configuration as well as lower costs for aftermarket ROPS. Various plastics were examined through shear testing, scale model testing, and compressive strength testing. Once a material was chosen based upon strength and cost, full-scale testing of the plastic's strength on axle housings was conducted. Finally, a mounting structure was tested in static ROPS tests, and field upset tests were performed in accordance with SAE Standard J2194. Initial tests revealed that the ROPS mounting structure and axle housing combination had higher torsional strength with less twisting than the axle housing alone. An engineering plastic ROPS mounting structure was easily successful in withstanding the forces applied during the static longitudinal and lateral ROPS tests. Field upset testing revealed that the mounting structure could withstand the impact loads seen during actual upsets without a failure. During both static testing and field upset testing, no permanent twisting of the mounting structure was found. Engineering plastic could therefore be a viable option for a universal ROPS mounting structure for older tractors.

Characterization of Structural Rebuilding and Shear Migration in Cementitious Materials in Consideration of Thixotropy

NASA Astrophysics Data System (ADS)

Qian, Ye

Characterization of structural rebuilding and shear migration in cementitious materials in consideration of thixotropy Ye Qian From initial contact with water until hardening, and deterioration, cement and concrete materials are subjected to various chemical and physical transformations and environmental impacts. This thesis focuses on the properties during the fresh state, shortly after mixing until the induction period. During this period flow history, including shearing and resting, and hydration both play big roles in determining the rheological properties. The rheological properties of cement and concrete not only affect the casting and pumping process, but also very critical for harden properties and durability properties. Compared with conventional concrete, self-consolidating concrete (SCC) can introduce many advantages in construction application. These include readiness to apply, decreasing labor necessary for casting, and enhancing hardened properties. However, challenges still remain, such as issues relating to formwork pressure and multi-layer casting. Each of these issues is closely related to the property of thixotropy. From the microstructural point of view, thixotropy is described as structural buildup (flocculation) under rest and breakdown (deflocculation) under flow. For SCC, as well as other concrete systems, it is about balancing sufficient flowability during casting and rate of structural buildup after placement for the application at hand. For instance, relating to the issue of SCC formwork, it is ideal for the material to be highly flowable to achieve rapid casting, but then exhibit high rate of structural buildup to reduce formwork pressure. This can reduce the cost of formwork and reduce the risk of formwork failure. It is apparent that accurately quantifying the two aspects of thixotropy, i.e. structuration and destructuration, is key to tackling these challenges in field application. Thus, the overall objective of my doctoral study is to improve quantification of key parameters tied to thixotropy that we have identified to be important: static yield stress, cohesion and degree of shear-induced particle migration. The two main contributions are as follows: Firstly, I quantified structuration of fresh paste and mortar systems by measuring static yield stress. After an extensive review of various rheological methods to probe viscoelastic properties of yield stress fluids, I selected, developed, and implemented a creep recovery protocol. Creep results were supplemented by low-amplitude oscillatory shear results, and supported that the measured static yield stress corresponds to the solid-liquid transition. This improved quantification of static yield stress can help better understand the effect of mix composition on SCC formwork pressure development, as well as static segregation and stability. Since the static yield stress is measured before the structure is broken down, the effects of sand migration are eliminated. This study also analyzed effects of other supplementary cementitous materials such as nanoclay and fly ash. Results showed that nanoclay effectively increases static yield stress and structuration rate, while fly ash decreases static yield stress. To complement this investigation, I studied cohesion using the probe tack test, as cohesion is widely cited to be closely related to formwork pressure. I verified that probe tack test is a quick and useful method to measure static cohesion. Results showed that nanoclay increased cohesion dramatically while fly ash did not have an apparent effect on cohesion. Secondly, I developed an empirical model to fit the stress decay process under constant shear rate, For mortar systems, the stress decay can be attributed to two mechanisms: colloidal destructuration and sand migration. Such a model could be used to characterize particle migration and dynamic segregation, a critical issue for casting applications. In addition, shear induced particle migration is a widely recognized challenge in characterizing mortars and concretes through shear rheological methods. Therefore this model can help determine the range of shear rates within which migration can be minimized to guide the design of protocols for dynamic rheological characterization and to ultimately develop design strategies to minimize mitigation. Compared with currently existing methods, this model provides a faster approach to quantify the sand migration process, including kinetics.

Static properties and moisture content properties of polyester fabrics modified by plasma treatment and chemical finishing

NASA Astrophysics Data System (ADS)

Kan, C. W.; Yuen, C. W. M.

2008-01-01

Low temperature plasma treatment has been conducted in textile industry and has some success in the dyeing and finishing processes. In this paper, an attempt was made to apply low temperature plasma treatment to improve the anti-static property of polyester fabric. The polyester fabrics were treated under different conditions using low temperature plasma. An Orthogonal Array Testing Strategy was employed to determine the optimum treatment condition. After low temperature plasma treatment, the polyester fabrics were evaluated with different characterisation methods. Under the observation of scanning electron microscope, the surface structure of low temperature plasma-treated polyester fabric was seriously altered. This provided more capacity for polyester to capture moisture and hence increase the dissipation of static charges. The relationship between moisture content and half-life decay time for static charges was studied and the results showed that the increment of moisture content would result in shortening the time for the dissipation of static charges. Moreover, there was a great improvement in the anti-static property of the low temperature plasma-treated polyester fabric after comparing with that of the polyester fabric treated with commercial anti-static finishing agent.

35. VIEW LOOKING NORTHWEST AT THE STATIC TEST TOWER. A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. VIEW LOOKING NORTHWEST AT THE STATIC TEST TOWER. A 'DUMMY' SATURN I BOOSTER IS BEING HOISTED INTO THE TEST STAND TO TEST THE MATING OF THE BOOSTER AND THE TEST STAND. EARLY 1960, PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Effect of Ankle Range of Motion (ROM) and Lower-Extremity Muscle Strength on Static Balance Control Ability in Young Adults: A Regression Analysis

PubMed Central

Kim, Seong-Gil

2018-01-01

Background The purpose of this study was to investigate the effect of ankle ROM and lower-extremity muscle strength on static balance control ability in young adults. Material/Methods This study was conducted with 65 young adults, but 10 young adults dropped out during the measurement, so 55 young adults (male: 19, female: 36) completed the study. Postural sway (length and velocity) was measured with eyes open and closed, and ankle ROM (AROM and PROM of dorsiflexion and plantarflexion) and lower-extremity muscle strength (flexor and extensor of hip, knee, and ankle joint) were measured. Pearson correlation coefficient was used to examine the correlation between variables and static balance ability. Simple linear regression analysis and multiple linear regression analysis were used to examine the effect of variables on static balance ability. Results In correlation analysis, plantarflexion ROM (AROM and PROM) and lower-extremity muscle strength (except hip extensor) were significantly correlated with postural sway (p<0.05). In simple correlation analysis, all variables that passed the correlation analysis procedure had significant influence (p<0.05). In multiple linear regression analysis, plantar flexion PROM with eyes open significantly influenced sway length (B=0.681) and sway velocity (B=0.011). Conclusions Lower-extremity muscle strength and ankle plantarflexion ROM influenced static balance control ability, with ankle plantarflexion PROM showing the greatest influence. Therefore, both contractile structures and non-contractile structures should be of interest when considering static balance control ability improvement. PMID:29760375

Effect of Ankle Range of Motion (ROM) and Lower-Extremity Muscle Strength on Static Balance Control Ability in Young Adults: A Regression Analysis.

PubMed

Kim, Seong-Gil; Kim, Wan-Soo

2018-05-15

BACKGROUND The purpose of this study was to investigate the effect of ankle ROM and lower-extremity muscle strength on static balance control ability in young adults. MATERIAL AND METHODS This study was conducted with 65 young adults, but 10 young adults dropped out during the measurement, so 55 young adults (male: 19, female: 36) completed the study. Postural sway (length and velocity) was measured with eyes open and closed, and ankle ROM (AROM and PROM of dorsiflexion and plantarflexion) and lower-extremity muscle strength (flexor and extensor of hip, knee, and ankle joint) were measured. Pearson correlation coefficient was used to examine the correlation between variables and static balance ability. Simple linear regression analysis and multiple linear regression analysis were used to examine the effect of variables on static balance ability. RESULTS In correlation analysis, plantarflexion ROM (AROM and PROM) and lower-extremity muscle strength (except hip extensor) were significantly correlated with postural sway (p<0.05). In simple correlation analysis, all variables that passed the correlation analysis procedure had significant influence (p<0.05). In multiple linear regression analysis, plantar flexion PROM with eyes open significantly influenced sway length (B=0.681) and sway velocity (B=0.011). CONCLUSIONS Lower-extremity muscle strength and ankle plantarflexion ROM influenced static balance control ability, with ankle plantarflexion PROM showing the greatest influence. Therefore, both contractile structures and non-contractile structures should be of interest when considering static balance control ability improvement.

Reaction trajectory revealed by a joint analysis of protein data bank.

PubMed

Ren, Zhong

2013-01-01

Structural motions along a reaction pathway hold the secret about how a biological macromolecule functions. If each static structure were considered as a snapshot of the protein molecule in action, a large collection of structures would constitute a multidimensional conformational space of an enormous size. Here I present a joint analysis of hundreds of known structures of human hemoglobin in the Protein Data Bank. By applying singular value decomposition to distance matrices of these structures, I demonstrate that this large collection of structural snapshots, derived under a wide range of experimental conditions, arrange orderly along a reaction pathway. The structural motions along this extensive trajectory, including several helical transformations, arrive at a reverse engineered mechanism of the cooperative machinery (Ren, companion article), and shed light on pathological properties of the abnormal homotetrameric hemoglobins from α-thalassemia. This method of meta-analysis provides a general approach to structural dynamics based on static protein structures in this post genomics era.

Reaction Trajectory Revealed by a Joint Analysis of Protein Data Bank

PubMed Central

Ren, Zhong

2013-01-01

Structural motions along a reaction pathway hold the secret about how a biological macromolecule functions. If each static structure were considered as a snapshot of the protein molecule in action, a large collection of structures would constitute a multidimensional conformational space of an enormous size. Here I present a joint analysis of hundreds of known structures of human hemoglobin in the Protein Data Bank. By applying singular value decomposition to distance matrices of these structures, I demonstrate that this large collection of structural snapshots, derived under a wide range of experimental conditions, arrange orderly along a reaction pathway. The structural motions along this extensive trajectory, including several helical transformations, arrive at a reverse engineered mechanism of the cooperative machinery (Ren, companion article), and shed light on pathological properties of the abnormal homotetrameric hemoglobins from α-thalassemia. This method of meta-analysis provides a general approach to structural dynamics based on static protein structures in this post genomics era. PMID:24244274

Outer planet probe engineering model structural tests

NASA Technical Reports Server (NTRS)

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Validation of Laser-Induced Fluorescent Photogrammetric Targets on Membrane Structures

NASA Technical Reports Server (NTRS)

Jones, Thomas W.; Dorrington, Adrian A.; Shortis, Mark R.; Hendricks, Aron R.

2004-01-01

The need for static and dynamic characterization of a new generation of inflatable space structures requires the advancement of classical metrology techniques. A new photogrammetric-based method for non-contact ranging and surface profiling has been developed at NASA Langley Research Center (LaRC) to support modal analyses and structural validation of this class of space structures. This full field measurement method, known as Laser-Induced Fluorescence (LIF) photogrammetry, has previously yielded promising experimental results. However, data indicating the achievable measurement precision had not been published. This paper provides experimental results that indicate the LIF-photogrammetry measurement precision for three different target types used on a reflective membrane structure. The target types were: (1) non-contact targets generated using LIF, (2) surface attached retro-reflective targets, and (3) surface attached diffuse targets. Results from both static and dynamic investigations are included.

Computational Simulation of Composite Structural Fatigue

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

2005-01-01

Progressive damage and fracture of composite structures subjected to monotonically increasing static, tension-tension cyclic, pressurization, and flexural cyclic loading are evaluated via computational simulation. Constituent material properties, stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for composites. Damage initiation, growth, accumulation, and propagation to fracture due to monotonically increasing static and cyclic loads are included in the simulations. Results show the number of cycles to failure at different temperatures and the damage progression sequence during different degradation stages. A procedure is outlined for use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of results with insight for design decisions.

Computational Simulation of Composite Structural Fatigue

NASA Technical Reports Server (NTRS)

Minnetyan, Levon

2004-01-01

Progressive damage and fracture of composite structures subjected to monotonically increasing static, tension-tension cyclic, pressurization, and flexural cyclic loading are evaluated via computational simulation. Constituent material properties, stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for composites. Damage initiation, growth, accumulation, and propagation to fracture due to monotonically increasing static and cyclic loads are included in the simulations. Results show the number of cycles to failure at different temperatures and the damage progression sequence during different degradation stages. A procedure is outlined for use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of results with insight for design decisions.

Static and dynamic structural-sensitivity derivative calculations in the finite-element-based Engineering Analysis Language (EAL) system

NASA Technical Reports Server (NTRS)

Camarda, C. J.; Adelman, H. M.

1984-01-01

The implementation of static and dynamic structural-sensitivity derivative calculations in a general purpose, finite-element computer program denoted the Engineering Analysis Language (EAL) System is described. Derivatives are calculated with respect to structural parameters, specifically, member sectional properties including thicknesses, cross-sectional areas, and moments of inertia. Derivatives are obtained for displacements, stresses, vibration frequencies and mode shapes, and buckling loads and mode shapes. Three methods for calculating derivatives are implemented (analytical, semianalytical, and finite differences), and comparisons of computer time and accuracy are made. Results are presented for four examples: a swept wing, a box beam, a stiffened cylinder with a cutout, and a space radiometer-antenna truss.

Stress Analysis of Columns and Beam Columns by the Photoelastic Method

NASA Technical Reports Server (NTRS)

Ruffner, B F

1946-01-01

Principles of similarity and other factors in the design of models for photoelastic testing are discussed. Some approximate theoretical equations, useful in the analysis of results obtained from photoelastic tests are derived. Examples of the use of photoelastic techniques and the analysis of results as applied to uniform and tapered beam columns, circular rings, and statically indeterminate frames, are given. It is concluded that this method is an effective tool for the analysis of structures in which column action is present, particularly in tapered beam columns, and in statically indeterminate structures in which the distribution of loads in the structures is influenced by bending moments due to axial loads in one or more members.

1, 25-dihydroxy-vitamin D3 with tumor necrosis factor-alpha protects against rheumatoid arthritis by promoting p53 acetylation-mediated apoptosis via Sirt1 in synoviocytes

PubMed Central

Gu, Xin; Gu, Bingjie; Lv, Xianhui; Yu, Zhenzhen; Wang, Rong; Zhou, Xiaoli; Qiao, Wanxin; Mao, Zhiyuan; Zuo, Guoping; Li, Qing; Miao, Dengshun; Jin, Jianliang

2016-01-01

Impaired apoptosis of fibroblast-like synoviocytes (FLSs) causes synovial hyperplasia, facilitating destruction of cartilage and bone in rheumatoid arthritis (RA). Tumor necrosis factor (TNF)-α, a dominant inflammatory mediator in RA pathogenesis, promotes progression of RA symptoms. Prevalence of 1, 25-dihydroxy-vitamin D3 (hereafter termed VD) deficiency is 30–63% in patients with RA. Whether VD leads to apoptosis or enhances TNF-α-mediated apoptosis in FLSs to ameliorate RA is unclear. To determine this, 10-week-old CYP27B1-deficient (CYP27B1−/−) mice with collagen-induced arthritis (CIA) were intraperitoneally treated with 1 μg/kg VD every other day for 9 weeks. RA phenotypes were compared between vehicle-treated CYP27B1−/− and wild-type CIA mice. Human rheumatoid FLS-MH7A cells were treated with Dulbecco's modified Eagle's medium (DMEM) without fetal bovine serum (FBS) for 24 h, then with different concentrations of VD and TNF-α, human vitamin D receptor (VDR) siRNA or the p53 pro-apoptotic inhibitor pifithrin-α. Apoptosis and p53 pro-apoptotic signaling were analyzed. The 19-week-old vehicle-treated CYP27B1−/− CIA mice had increased cumulative arthritis scores and levels of serous rheumatoid factors and C-reactive protein. They had exacerbated articular cartilage and bone destruction, joint space narrowing, joint stiffness, deformity and dysfunction, synovitis and TNF-α secretion, FLS hyperplasia with increased proliferation and decreased apoptosis compared to CIA mice. These RA phenotypes that were aggravated in CIA mice by CYP27B1 deficiency were largely rescued by VD treatment. In vitro, VD with TNF-α treatment upregulated p53 acetylation-mediated apoptosis in MH7A cells by promoting Sirt1 translocation from the nucleus to the cytoplasm. These findings indicated that VD with TNF-α protected against RA by promoting apoptosis of FLSs. The results indicated that clinical administration of VD could be a specific therapy to promote FLS apoptosis and prevent RA progression. PMID:27763638

MicroRNA-146a suppresses rheumatoid arthritis fibroblast-like synoviocytes proliferation and inflammatory responses by inhibiting the TLR4/NF-kB signaling

PubMed Central

Liu, Wei; Wu, Yuan-Hao; Zhang, Lei; Xue, Bin; Wang, Yi; Liu, Bin; Liu, Xiao-Ya; Zuo, Fang; Yang, Xiao-Yan; Chen, Fu-Yu; Duan, Ran; Cai, Yue; Zhang, Bo; Ji, Yang

2018-01-01

This study investigated whether microRNA-146a (miR-146a) mediating TLR4/NF-κB pathway affected proliferation and inflammatory responses of rheumatoid arthritis fibroblast-like synoviocytes from 12 RA patients (RA-FLSs). FLSs in the logarithmic growth phase were assigned into the control, miR-146a mimic miR-146a inhibitor, Tak-242 (treated with TLR4/NF-κB pathway inhibitor) and mimic + lipopolysaccharide (LPS) groups. Cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry. The expression of miR-146a, TLR4/NF-κB pathway-related proteins and cytokines were determined by RT-qPCR, western blotting and ELISA, and the release of NO by Greiss reaction. RA rat models were constructed and the primary cells were classified into the control, negative control (NC), miR-146a mimic, miR-146a inhibitor, Tak-242, mimic + LPS, and TLR4 groups. Immunohistochemistry was used to detect the expression of proliferating cell nuclear antigen (PCNA) and intercellular adhesion molecular-1 (ICAM-1). The results showed that miR-146a levels were lower in RA-FLSs than control fibroblasts. miR-146a mimic and Tak-242 decreased RA-FLS proliferation and increased RA-FLS apoptosis, while miR-146a inhibitor had an opposite trend. miR-146a mimic and Tak-242 also decreased expression of TLR4, NF-κB, IL-1β, IL-6, IL-8, IL-17, COX-2, MMP-3, Seprase, and iNOS, as well as reduced NO level in RA-FLSs while miR-146a inhibitor and TLR4 increased them. TLR4 and NF-κB levels and the positive rates of PCNA and ICAM-1 expressions were lower in RA-FLSs from RA rats given miR-146a mimic from control or miR-146a inhibitor-treated rats. These results suggest that miR-146a inhibits the proliferation and inflammatory response of RA-FLSs by down-regulating TLR4/NF-κB pathway.

Advanced oxidation protein products induce inflammatory response in fibroblast-like synoviocytes through NADPH oxidase -dependent activation of NF-κB.

PubMed

Zheng, Shuai; Zhong, Zhao-Ming; Qin, Shuai; Chen, Guo-Xian; Wu, Qian; Zeng, Ji-Huan; Ye, Wen-Bin; Li, Wei; Yuan, Kai; Yao, Ling; Chen, Jian-Ting

2013-01-01

Advanced oxidation protein products (AOPPs), a marker of oxidative stress, are prevalent in many kinds of disorders. Rheumatoid arthritis (RA), mainly resulting from the dysfunction of fibroblast-like synoviocytes (FLSs), is related to oxidative stress. Although the increased levels of AOPPs in RA patients were reported, the effect of AOPPs on FLSs function still remains unclear. Therefore, our study aims to investigate whether AOPPs have an effect on the inflammatory response of FLSs in vitro. FLSs obtained from both knees of rats were treated with or without AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. The mRNA and protein expression of tumor necrosis factor (TNF)-α, interleukin(IL)-1β, matrix metalloproteinases(MMP)-3, MMP-13 and vascular endothelial growth factor (VEGF) were measured by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA), respectively. Reactive oxygen species (ROS) generation was detected by fluorescent microscope and fluorescence microplate reader. Immunoprecipitation, Co-Immunoprecipitation and western blot were performed to examine the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and nuclear factor kappa B (NF-κB). Exposure of FLSs to AOPPs upregulated the mRNA and protein expression of TNF-α, IL-1β, MMP-3, MMP-13 and VEGF in a concentration dependent manner. AOPPs treatment triggered ROS production in FLSs, which was significantly abolished by ROS scavenger N-acetyl-L-cysteine (NAC), superoxide dismutase (SOD), NADPH oxidase inhibitors diphenyleneiodonium (DPI) and apocynin. Challenged AOPPs induced phosphorylation of p47(phox), triggered an interaction between p47(phox), p22(phox) and gp91(phox), and significantly upregulated expression of NADPH oxidase subunits p47(phox), p22(phox) and gp91(phox). IκB degradation and nuclear translocation of NF-κB p65 induced by AOPPs were significantly blocked by SOD, NAC, DPI and apocynin. These data indicate that AOPPs induce inflammatory response in FLSs is medicated through NADPH oxidase-dependent activation of NF-κB. © 2013 S. Karger AG, Basel

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed

Schröter, Tobias J; Johnson, Shane B; John, Kerstin; Santi, Peter A

2012-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. 2011 Optical Society of America

Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading

NASA Astrophysics Data System (ADS)

Armaghani, Seyamend Bilind

Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences between static and dynamic behavior, Preliminary three point bending testing was conducted to determine the parameters for the final experiments. Static bending testing was conducted on the bare, plywood composite, and fiberglass composite steel tubing. The point of these experiments was to produce a Moment vs. Rotation plot to determine the specimens' maximum moments and their associated rotation, as that is when the steel buckles and fails. The dynamic three point bending experiments were conducted using the impact loading apparatus and had the same purpose as the static experiments. For both static and dynamic experiments, the performances of the different types of specimens were compared based upon their Moment vs. Rotation plots. This will determine the effect that the composite has on the rotation and maximum moment at which the tubing fails. After conducting these experiments, amplification factors were established for each specimen by comparing the maximum moment and their associated rotation between static and dynamic testing. lambda was calculated to quantify the ratio between the static and dynamic maximum moments. beta was used to quantify the ratio between the rotation needed to produce the maximum moment between static and dynamic events. A small amplification factor denotes that material performs well under impact loading and the material doesn't experience dramatic change in behavior during dynamic events. Amplification factors were compared between the bare, plywood, and fiberglass composite steel tubing in order to evaluate the performance of the composites. After comparing the amplification factors of the different types of tubing, recommendations can be made. Fiberglass and plywood composite were shown to be valuable because it decreased the effect of dynamic forces as beta was reduced by a factor of 2 in comparison to bare tubing. Based upon the amplification factors, it was recommended to use 14 gauge fiberglass composite tubing as Paratransit bus structural members because it was affected the least by dynamic loading.

Relationship between Alfvén Wave and Quasi-Static Acceleration in Earth's Auroral Zone

NASA Astrophysics Data System (ADS)

Mottez, Fabrice

2016-02-01

There are two main categories of acceleration processes in the Earth's auroral zone: those based on quasi-static structures, and those based on Alfvén wave (AW). AWs play a nonnegligible role in the global energy budget of the plasma surrounding the Earth because they participate in auroral acceleration, and because auroral acceleration conveys a large portion of the energy flux across the magnetosphere. Acceleration events by double layers (DLs) and by AW have mostly been investigated separately, but many studies cited in this chapter show that they are not independent: these processes can occur simultaneously, and one process can be the cause of the other. The quasi-simultaneous occurrences of acceleration by AW and by quasi-static structures have been observed predominantly at the polar cap boundary of auroral arc systems, where often new bright arcs develop or intensify.

An ab initio study of the structure and atomic transport in bulk liquid Ag and its liquid-vapor interface

NASA Astrophysics Data System (ADS)

del Rio, Beatriz G.; González, David J.; González, Luis E.

2016-10-01

Several static and dynamic properties of bulk liquid Ag at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals propagating excitations whose dispersion at long wavelengths is compatible with the experimental sound velocity. Results are also reported for other transport coefficients. Additional simulations have also been performed so as to study the structure of the free liquid surface. The calculated longitudinal ionic density profile shows an oscillatory behaviour, whose properties are analyzed through macroscopic and microscopic methods. The intrinsic X-ray reflectivity of the surface is predicted to show a layering peak associated to the interlayer distance.

Flutter Sensitivity to Boundary Layer Thickness, Structural Damping, and Static Pressure Differential for a Shuttle Tile Overlay Repair Concept

NASA Technical Reports Server (NTRS)

Scott, Robert C.; Bartels, Robert E.

2009-01-01

This paper examines the aeroelastic stability of an on-orbit installable Space Shuttle patch panel. CFD flutter solutions were obtained for thick and thin boundary layers at a free stream Mach number of 2.0 and several Mach numbers near sonic speed. The effect of structural damping on these flutter solutions was also examined, and the effect of structural nonlinearities associated with in-plane forces in the panel was considered on the worst case linear flutter solution. The results of the study indicated that adequate flutter margins exist for the panel at the Mach numbers examined. The addition of structural damping improved flutter margins as did the inclusion of nonlinear effects associated with a static pressure difference across the panel.

Analysis of SMA Hybrid Composite Structures in MSC.Nastran and ABAQUS

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Patel, Hemant D.

2005-01-01

A thermoelastic constitutive model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures was recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilever beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilever beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

NASA Technical Reports Server (NTRS)

Kohlman, Lee W.; Ruggeri, Charles R.; Roberts, Gary D.; Handschuh, Robert Frederick

2013-01-01

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests

Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

NASA Technical Reports Server (NTRS)

Kohlman, Lee; Ruggeri, Charles; Roberts, Gary; Handshuh, Robert

2013-01-01

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.

Analysis of SMA Hybrid Composite Structures using Commercial Codes

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Patel, Hemant D.

2004-01-01

A thermomechanical model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures has been recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilevered beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilevered beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

Optimal Multi-Type Sensor Placement for Structural Identification by Static-Load Testing

PubMed Central

Papadopoulou, Maria; Vernay, Didier; Smith, Ian F. C.

2017-01-01

Assessing ageing infrastructure is a critical challenge for civil engineers due to the difficulty in the estimation and integration of uncertainties in structural models. Field measurements are increasingly used to improve knowledge of the real behavior of a structure; this activity is called structural identification. Error-domain model falsification (EDMF) is an easy-to-use model-based structural-identification methodology which robustly accommodates systematic uncertainties originating from sources such as boundary conditions, numerical modelling and model fidelity, as well as aleatory uncertainties from sources such as measurement error and material parameter-value estimations. In most practical applications of structural identification, sensors are placed using engineering judgment and experience. However, since sensor placement is fundamental to the success of structural identification, a more rational and systematic method is justified. This study presents a measurement system design methodology to identify the best sensor locations and sensor types using information from static-load tests. More specifically, three static-load tests were studied for the sensor system design using three types of sensors for a performance evaluation of a full-scale bridge in Singapore. Several sensor placement strategies are compared using joint entropy as an information-gain metric. A modified version of the hierarchical algorithm for sensor placement is proposed to take into account mutual information between load tests. It is shown that a carefully-configured measurement strategy that includes multiple sensor types and several load tests maximizes information gain. PMID:29240684

The analysis of dynamic characteristics and wind-induced displacement response of space Beam String Structure

NASA Astrophysics Data System (ADS)

Chen, Yong Jian; Feng, Zhen Fa; Qi, Ai; Huang, Ying

2018-06-01

The Beam String Structure structural system, also called BSS, has the advantages of lighter dead weight and greater flexibility. The wind load is the main design control factor. The dynamic characteristics and wind-induced displacement response of BSS are studied by the finite element method. The roof structure of the stadium roof of the Fuzhou Olympic Sports Center is the engineering background. 1)The numerical model was built by ANSYS, by shape finding, determine the initial stress state of structural members such as external cables; 2)From the analysis of dynamic characteristics, the main mode of vibration is the vibration of cables; 3)The wind speed spectrum of MATLAB generation structure is obtained by AR method, the structural response of the structure under static wind load and fluctuating wind load is calculated. From the analysis result, considering the equivalent static wind load of BSS , the design of adverse wind is not safe, and the fluctuating wind load should be taken into account.

Additive-manufactured sandwich lattice structures: A numerical and experimental investigation

NASA Astrophysics Data System (ADS)

Fergani, Omar; Tronvoll, Sigmund; Brøtan, Vegard; Welo, Torgeir; Sørby, Knut

2017-10-01

The utilization of additive-manufactured lattice structures in engineered products is becoming more and more common as the competitiveness of AM as a production technology has increased during the past several years. Lattice structures may enable important weight reductions as well as open opportunities to build products with customized functional properties, thanks to the flexibility of AM for producing complex geometrical configurations. One of the most critical aspects related to taking AM into new application areas—such as safety critical products—is currently the limited understanding of the mechanical behavior of sandwich-based lattice structure mechanical under static and dynamic loading. In this study, we evaluate manufacturability of lattice structures and the impact of AM processing parameters on the structural behavior of this type of sandwich structures. For this purpose, we conducted static compression testing for a variety of geometry and manufacturing parameters. Further, the study discusses a numerical model capable of predicting the behavior of different lattice structure. A reasonably good correlation between the experimental and numerical results was observed.

Finite element modeling of ROPS in static testing and rear overturns.

PubMed

Harris, J R; Mucino, V H; Etherton, J R; Snyder, K A; Means, K H

2000-08-01

Even with the technological advances of the last several decades, agricultural production remains one of the most hazardous occupations in the United States. Death due to tractor rollover is a prime contributor to this hazard. Standards for rollover protective structures (ROPS) performance and certification have been developed by groups such as the Society of Automotive Engineers (SAE) and the American Society of Agricultural Engineers (ASAE) to combat these problems. The current ROPS certification standard, SAE J2194, requires either a dynamic or static testing sequence or both. Although some ROPS manufacturers perform both the dynamic and static phases of SAE J2194 testing, it is possible for a ROPS to be certified for field operation using static testing alone. This research compared ROPS deformation response from a simulated SAE J2194 static loading sequence to ROPS deformation response as a result of a simulated rearward tractor rollover. Finite element analysis techniques for plastic deformation were used to simulate both the static and dynamic rear rollover scenarios. Stress results from the rear rollover model were compared to results from simulated static testing per SAE J2194. Maximum stress values from simulated rear rollovers exceeded maximum stress values recorded during simulated static testing for half of the elements comprising the uprights. In the worst case, the static model underpredicts dynamic model results by approximately 7%. In the best case, the static model overpredicts dynamic model results by approximately 32%. These results suggest the need for additional experimental work to characterize ROPS stress levels during staged overturns and during testing according to the SAE standard.

Degradation of learned skills. Static practice effectiveness for visual approach and landing skill retention

NASA Technical Reports Server (NTRS)

Sitterley, T. E.

1974-01-01

The effectivess of an improved static retraining method was evaluated for a simulated space vehicle approach and landing under instrument and visual flight conditions. Experienced pilots were trained and then tested after 4 months without flying to compare their performance using the improved method with three methods previously evaluated. Use of the improved static retraining method resulted in no practical or significant skill degradation and was found to be even more effective than methods using a dynamic presentation of visual cues. The results suggested that properly structured open loop methods of flight control task retraining are feasible.

Convergent beam electron-diffraction investigation of lattice mismatch and static disorder in GaAs/GaAs1-xNx intercalated GaAs/GaAs1-xNx:H heterostructures

NASA Astrophysics Data System (ADS)

Frabboni, S.; Grillo, V.; Gazzadi, G. C.; Balboni, R.; Trotta, R.; Polimeni, A.; Capizzi, M.; Martelli, F.; Rubini, S.; Guzzinati, G.; Glas, F.

2012-09-01

Hydrogen incorporation in diluted nitride semiconductors dramatically modifies the electronic and structural properties of the crystal through the creation of nitrogen-hydrogen complexes. We report a convergent beam electron-diffraction characterization of diluted nitride semiconductor-heterostructures patterned at a sub-micron scale and selectively exposed to hydrogen. We present a method to determine separately perpendicular mismatch and static disorder in pristine and hydrogenated heterostructures. The roles of chemical composition and strain on static disorder have been separately assessed.

A domain decomposition approach to implementing fault slip in finite-element models of quasi-static and dynamic crustal deformation

USGS Publications Warehouse

Aagaard, Brad T.; Knepley, M.G.; Williams, C.A.

2013-01-01

We employ a domain decomposition approach with Lagrange multipliers to implement fault slip in a finite-element code, PyLith, for use in both quasi-static and dynamic crustal deformation applications. This integrated approach to solving both quasi-static and dynamic simulations leverages common finite-element data structures and implementations of various boundary conditions, discretization schemes, and bulk and fault rheologies. We have developed a custom preconditioner for the Lagrange multiplier portion of the system of equations that provides excellent scalability with problem size compared to conventional additive Schwarz methods. We demonstrate application of this approach using benchmarks for both quasi-static viscoelastic deformation and dynamic spontaneous rupture propagation that verify the numerical implementation in PyLith.

Thermal static bending of deployable interlocked booms

NASA Technical Reports Server (NTRS)

Staugaitis, C. L.; Predmore, R. E.

1973-01-01

Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

Elevated-Temperature Tests Under Static and Aerodynamic Conditions on Honeycomb-Core Sandwich Panels

NASA Technical Reports Server (NTRS)

Groen, Joseph M.; Johnson, Aldie E., Jr.

1959-01-01

Stainless-steel honeycomb-core sandwich panels which differed primarily in skin thicknesses were tested at elevated temperatures under static and aerodynamic conditions. The results of these tests were evaluated to determine the insulating effectiveness and structural integrity of the panels. The static radiant-heating tests were performed in front of a quartz-tube radiant heater at panel skin temperatures up to 1,5000 F. The aerodynamic tests were made in a Mach 1.4 heated blowdown wind tunnel. The tunnel temperature was augmented by additional heat supplied by a radiant heater which raised the panel surface temperature above 8000 F during air flow. Static radiant-heating tests of 2 minutes duration showed that all the panels protected the load-carrying structure about equally well. Thin-skin panels showed an advantage for this short-time test over thick-skin panels from a standpoint of weight against insulation. Permanent inelastic strains in the form of local buckles over each cell of the honeycomb core caused an increase in surface roughness. During the aero- dynamic tests all of the panels survived with little or no damage, and panel flutter did not occur.

Quasi-Static Magnetic Field Shielding Using Longitudinal Mu-Near-Zero Metamaterials.

PubMed

Lipworth, Guy; Ensworth, Joshua; Seetharam, Kushal; Lee, Jae Seung; Schmalenberg, Paul; Nomura, Tsuyoshi; Reynolds, Matthew S; Smith, David R; Urzhumov, Yaroslav

2015-08-03

The control of quasi-static magnetic fields is of considerable interest in applications including the reduction of electromagnetic interference (EMI), wireless power transfer (WPT), and magnetic resonance imaging (MRI). The shielding of static or quasi-static magnetic fields is typically accomplished through the use of inherently magnetic materials with large magnetic permeability, such as ferrites, used sometimes in combination with metallic sheets and/or active field cancellation. Ferrite materials, however, can be expensive, heavy and brittle. Inspired by recent demonstrations of epsilon-, mu- and index-near-zero metamaterials, here we show how a longitudinal mu-near-zero (LMNZ) layer can serve as a strong frequency-selective reflector of magnetic fields when operating in the near-field region of dipole-like sources. Experimental measurements with a fabricated LMNZ sheet constructed from an artificial magnetic conductor - formed from non-magnetic, conducting, metamaterial elements - confirm that the artificial structure provides significantly improved shielding as compared with a commercially available ferrite of the same size. Furthermore, we design a structure to shield simultaneously at the fundamental and first harmonic frequencies. Such frequency-selective behavior can be potentially useful for shielding electromagnetic sources that may also generate higher order harmonics, while leaving the transmission of other frequencies unaffected.

Active Polar Two-Fluid Macroscopic Dynamics

NASA Astrophysics Data System (ADS)

Pleiner, Harald; Svensek, Daniel; Brand, Helmut R.

2014-03-01

We study the dynamics of systems with a polar dynamic preferred direction. Examples include the pattern-forming growth of bacteria (in a solvent, shoals of fish (moving in water currents), flocks of birds and migrating insects (flying in windy air). Because the preferred direction only exists dynamically, but not statically, the macroscopic variable of choice is the macroscopic velocity associated with the motion of the active units. We derive the macroscopic equations for such a system and discuss novel static, reversible and irreversible cross-couplings connected to this second velocity. We find a normal mode structure quite different compared to the static descriptions, as well as linear couplings between (active) flow and e.g. densities and concentrations due to the genuine two-fluid transport derivatives. On the other hand, we get, quite similar to the static case, a direct linear relation between the stress tensor and the structure tensor. This prominent ``active'' term is responsible for many active effects, meaning that our approach can describe those effects as well. In addition, we also deal with explicitly chiral systems, which are important for many active systems. In particular, we find an active flow-induced heat current specific for the dynamic chiral polar order.

Static and Vibration Analyses of General Wing Structures Using Equivalent Plate Models

NASA Technical Reports Server (NTRS)

Kapania, Rakesh K.; Liu, Youhua

1999-01-01

An efficient method, using equivalent plate model, is developed for studying the static and vibration analyses of general built-up wing structures composed of skins, spars, and ribs. The model includes the transverse shear effects by treating the built-up wing as a plate following the Reissner-Mindlin theory, the so-called First-order Shear Deformation Theory (FSDT). The Ritz method is used with the Legendre polynomials being employed as the trial functions. This is in contrast to previous equivalent plate model methods which have used simple polynomials, known to be prone to numerical ill-conditioning, as the trial functions. The present developments are evaluated by comparing the results with those obtained using MSC/NASTRAN, for a set of examples. These examples are: (i) free-vibration analysis of a clamped trapezoidal plate with (a) uniform thickness, and (b) non-uniform thickness varying as an airfoil, (ii) free-vibration and static analyses (including skin stress distribution) of a general built-up wing, and (iii) free-vibration and static analyses of a swept-back box wing. The results obtained by the present equivalent plate model are in good agreement with those obtained by the finite element method.

The limp flywheel

NASA Astrophysics Data System (ADS)

Lerner, R. M.

1984-06-01

It is proposed to design and construct energy storage flywheel rotors as statically limp tubes containing liquid mass, and to drive and support this rotating system (at least in part) directly, rather than through separately engineered subsystems. If the liquid is presumed thixotropic or viscous, nominally stiff structures subject to plastic flow are included. At one extreme of the design range, nearly all the mass is in the liquid and the only significant stresses are those in the wall of the containment; at the other extreme, the statically limp structure is nearly dry and is formed into an oblate surface by the centrifugal force of its own mass.

Electronic structure and static dipole polarizability of C60@C240

NASA Astrophysics Data System (ADS)

Zope, Rajendra R.

2008-04-01

The electronic structure of C60@C240 and its first-order response to a static electric field is studied by an all-electron density functional theory calculation using large polarized Gaussian basis sets. Our results show that the outer C240 shell almost completely shields the inner C60 as inferred from the practically identical values of dipole polarizability of the C60@C240 onion (449 Å3) and that of the isolated C240 fullerene (441 Å3). The C60@C240 is thus a near-perfect Faraday cage.

Poroelastic metamaterials with negative effective static compressibility

NASA Astrophysics Data System (ADS)

Qu, Jingyuan; Kadic, Muamer; Wegener, Martin

2017-04-01

We suggest a three-dimensional metamaterial structure exhibiting an isotropic expansion in response to an increased hydrostatic pressure imposed by a surrounding gas or liquid. We show that this behavior corresponds to a negative absolute (rather than only differential) effective compressibility under truly static and stable conditions. The poroelastic metamaterial is composed of only a single ordinary constituent solid. By detailed numerical parameter studies, we find that a pressure increase of merely one bar can lead to a relative increase in the effective volume exceeding one percent for geometrical structure parameters that should be accessible to fabrication by 3D printing.

Static strain tuning of quantum dots embedded in a photonic wire

NASA Astrophysics Data System (ADS)

Tumanov, D.; Vaish, N.; Nguyen, H. A.; Curé, Y.; Gérard, J.-M.; Claudon, J.; Donatini, F.; Poizat, J.-Ph.

2018-03-01

We use strain to statically tune the semiconductor band gap of individual InAs quantum dots (QDs) embedded in a GaAs photonic wire featuring very efficient single photon collection. Thanks to the geometry of the structure, we are able to shift the QD excitonic transition by more than 25 meV by using nano-manipulators to apply the stress. Moreover, owing to the strong transverse strain gradient generated in the structure, we can relatively tune two QDs located in the wire waveguide and bring them in resonance, opening the way to the observation of collective effects such as superradiance.

On vibrational imperfection sensitivity of Augusti's model structure in the vicinity of a non-linear static state

NASA Technical Reports Server (NTRS)

Elishakoff, Isaac; Marcus, S.; Starnes, J. H., JR.

1998-01-01

In this paper we present a closed-form solution for vibrational imperfection sensitivity the effect of small imperfections on the vibrational frequencies of perturbed motion around the static equilibrium state of Augusti's model Structure (a rigid link, pinned at one end to a rigid foundation and supported at the other by a linear extensional spring that retains its horizontality, as the system deflects). We also treat a modified version of that model with attendant slightly different dynamics. It is demonstrated that the vibrational frequencies decreases as the initial imperfections increase.

14 CFR 23.572 - Metallic wing, empennage, and associated structures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... principal structural element, and that the remaining structure is able to withstand a static ultimate load... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES... experience: (1) A fatigue strength investigation in which the structure is shown by tests, or by analysis...

14 CFR 23.572 - Metallic wing, empennage, and associated structures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... principal structural element, and that the remaining structure is able to withstand a static ultimate load... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES... experience: (1) A fatigue strength investigation in which the structure is shown by tests, or by analysis...

14 CFR 23.572 - Metallic wing, empennage, and associated structures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... principal structural element, and that the remaining structure is able to withstand a static ultimate load... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES... experience: (1) A fatigue strength investigation in which the structure is shown by tests, or by analysis...

14 CFR 23.572 - Metallic wing, empennage, and associated structures.

Code of Federal Regulations, 2011 CFR

2011-01-01

... principal structural element, and that the remaining structure is able to withstand a static ultimate load... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES... experience: (1) A fatigue strength investigation in which the structure is shown by tests, or by analysis...

14 CFR 23.572 - Metallic wing, empennage, and associated structures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... principal structural element, and that the remaining structure is able to withstand a static ultimate load... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES... experience: (1) A fatigue strength investigation in which the structure is shown by tests, or by analysis...

Study on Finite Element Model Updating in Highway Bridge Static Loading Test Using Spatially-Distributed Optical Fiber Sensors

PubMed Central

Wu, Bitao; Lu, Huaxi; Chen, Bo; Gao, Zhicheng

2017-01-01

A finite model updating method that combines dynamic-static long-gauge strain responses is proposed for highway bridge static loading tests. For this method, the objective function consisting of static long-gauge stains and the first order modal macro-strain parameter (frequency) is established, wherein the local bending stiffness, density and boundary conditions of the structures are selected as the design variables. The relationship between the macro-strain and local element stiffness was studied first. It is revealed that the macro-strain is inversely proportional to the local stiffness covered by the long-gauge strain sensor. This corresponding relation is important for the modification of the local stiffness based on the macro-strain. The local and global parameters can be simultaneously updated. Then, a series of numerical simulation and experiments were conducted to verify the effectiveness of the proposed method. The results show that the static deformation, macro-strain and macro-strain modal can be predicted well by using the proposed updating model. PMID:28753912

Study on Finite Element Model Updating in Highway Bridge Static Loading Test Using Spatially-Distributed Optical Fiber Sensors.

PubMed

Wu, Bitao; Lu, Huaxi; Chen, Bo; Gao, Zhicheng

2017-07-19

A finite model updating method that combines dynamic-static long-gauge strain responses is proposed for highway bridge static loading tests. For this method, the objective function consisting of static long-gauge stains and the first order modal macro-strain parameter (frequency) is established, wherein the local bending stiffness, density and boundary conditions of the structures are selected as the design variables. The relationship between the macro-strain and local element stiffness was studied first. It is revealed that the macro-strain is inversely proportional to the local stiffness covered by the long-gauge strain sensor. This corresponding relation is important for the modification of the local stiffness based on the macro-strain. The local and global parameters can be simultaneously updated. Then, a series of numerical simulation and experiments were conducted to verify the effectiveness of the proposed method. The results show that the static deformation, macro-strain and macro-strain modal can be predicted well by using the proposed updating model.

Interaction mechanisms and biological effects of static magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenforde, T.S.

1994-06-01

Mechanisms through which static magnetic fields interact with living systems are described and illustrated by selected experimental observations. These mechanisms include electrodynamic interactions with moving, ionic charges (blood flow and nerve impulse conduction), magnetomechanical interactions (orientation and translation of molecules structures and magnetic particles), and interactions with electronic spin states in charge transfer reactions (photo-induced electron transfer in photosynthesis). A general summary is also presented of the biological effects of static magnetic fields. There is convincing experimental evidence for magnetoreception mechanisms in several classes of lower organisms, including bacteria and marine organisms. However, in more highly evolved species of animals,more » there is no evidence that the interactions of static magnetic fields with flux densities up to 2 Tesla (1 Tesla [T] = 10{sup 4} Gauss) produce either behavioral or physiolocical alterations. These results, based on controlled studies with laboratory animals, are consistent with the outcome of recent epidemiological surveys on human populations exposed occupationally to static magnetic fields.« less

Static and dynamic removal of aquatic natural organic matter by carbon nanotubes.

PubMed

Ajmani, Gaurav S; Cho, Hyun-Hee; Abbott Chalew, Talia E; Schwab, Kellogg J; Jacangelo, Joseph G; Huang, Haiou

2014-08-01

Carbon nanotubes (CNTs) were investigated for their capability and mechanisms to simultaneously remove colloidal natural organic matter (NOM) and humic substances from natural surface water. Static removal testing was conducted via adsorption experiments while dynamic removal was evaluated by layering CNTs onto substrate membranes and filtering natural water through the CNT-layered membranes. Analyses of treated water samples showed that removal of humic substances occurred via adsorption under both static and dynamic conditions. Removal of colloidal NOM occurred at a moderate level of 36-66% in static conditions, independent of the specific surface area (SSA) of CNTs. Dynamic removal of colloidal NOM increased from approximately 15% with the unmodified membrane to 80-100% with the CNT-modified membranes. Depth filtration played an important role in colloidal NOM removal. A comparison of the static and dynamic removal of humic substances showed that equilibrium static removal was higher than dynamic (p < 0.01), but there was also a significant linear relationship between static and dynamic removal (p < 0.05). Accounting for contact time of CNTs with NOM during filtration, it appeared that CNT mat structure was an important determinant of removal efficiencies for colloidal NOM and humic substances during CNT membrane filtration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nonlinear static and dynamic finite element analysis of an eccentrically loaded graphite-epoxy beam

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Jones, Lisa E.

1991-01-01

The Dynamic Crash Analysis of Structures (DYCAT) and NIKE3D nonlinear finite element codes were used to model the static and implulsive response of an eccentrically loaded graphite-epoxy beam. A 48-ply unidirectional composite beam was tested under an eccentric axial compressive load until failure. This loading configuration was chosen to highlight the capabilities of two finite element codes for modeling a highly nonlinear, large deflection structural problem which has an exact solution. These codes are currently used to perform dynamic analyses of aircraft structures under impact loads to study crashworthiness and energy absorbing capabilities. Both beam and plate element models were developed to compare with the experimental data using the DYCAST and NIKE3D codes.

Layerwise mechanics and finite element for the dynamic analysis of piezoelectric composite plates

NASA Technical Reports Server (NTRS)

Saravanos, Dimitris A.; Heyliger, Paul R.; Hopkins, Dale A.

1996-01-01

Laminate and structural mechanics for the analysis of laminated composite plate structures with piezoelectric actuators and sensors are presented. The theories implement layerwise representations of displacements and electric potential, and can model both the global and local electromechanical response of smart composite laminates. Finite-element formulations are developed for the quasi-static and dynamic analysis of smart composite structures containing piezoelectric layers. Comparisons with an exact solution illustrate the accuracy, robustness and capability of the developed mechanics to capture the global and local response of thin and/or thick laminated piezoelectric plates. Additional correlations and numerical applications demonstrate the unique capabilities of the mechanics in analyzing the static and free-vibration response of composite plates with distributed piezoelectric actuators and sensors.

Family Structure Changes during High School and College Selectivity

ERIC Educational Resources Information Center

An, Brian P.; Sorensen, Kia N.

2017-01-01

Research has shown that family structure changes negatively influence educational attainment, but they overlook qualitative distinctions in college choice, such as college selectivity. Yet, college choice research has largely focused on static measures of family structure, failing to account for year-to-year family structure changes that occur…

Investigation of Quasi-Static Indentation Response of Inkjet Printed Sandwich Structures under Various Indenter Geometries

PubMed Central

Dikshit, Vishwesh; Nagalingam, Arun Prasanth; Yap, Yee Ling; Sing, Swee Leong; Yeong, Wai Yee; Wei, Jun

2017-01-01

The objective of this investigation was to determine the quasi-static indentation response and failure mode in three-dimensional (3D) printed trapezoidal core structures, and to characterize the energy absorbed by the structures. In this work, the trapezoidal sandwich structure was designed in the following two ways. Firstly, the trapezoidal core along with its facesheet was 3D printed as a single element comprising a single material for both core and facesheet (type A); Secondly, the trapezoidal core along with facesheet was 3D printed, but with variation in facesheet materials (type B). Quasi-static indentation was carried out using three different indenters, namely standard hemispherical, conical, and flat indenters. Acoustic emission (AE) technique was used to capture brittle cracking in the specimens during indentation. The major failure modes were found to be brittle failure and quasi-brittle fractures. The measured indentation energy was at a maximum when using a conical indenter at 9.40 J and 9.66 J and was at a minimum when using a hemispherical indenter at 6.87 J and 8.82 J for type A and type B series specimens respectively. The observed maximum indenter displacements at failure were the effect of material variations and composite configurations in the facesheet. PMID:28772649

Investigation of Quasi-Static Indentation Response of Inkjet Printed Sandwich Structures under Various Indenter Geometries.

PubMed

Dikshit, Vishwesh; Nagalingam, Arun Prasanth; Yap, Yee Ling; Sing, Swee Leong; Yeong, Wai Yee; Wei, Jun

2017-03-14

The objective of this investigation was to determine the quasi-static indentation response and failure mode in three-dimensional (3D) printed trapezoidal core structures, and to characterize the energy absorbed by the structures. In this work, the trapezoidal sandwich structure was designed in the following two ways. Firstly, the trapezoidal core along with its facesheet was 3D printed as a single element comprising a single material for both core and facesheet (type A); Secondly, the trapezoidal core along with facesheet was 3D printed, but with variation in facesheet materials (type B). Quasi-static indentation was carried out using three different indenters, namely standard hemispherical, conical, and flat indenters. Acoustic emission (AE) technique was used to capture brittle cracking in the specimens during indentation. The major failure modes were found to be brittle failure and quasi-brittle fractures. The measured indentation energy was at a maximum when using a conical indenter at 9.40 J and 9.66 J and was at a minimum when using a hemispherical indenter at 6.87 J and 8.82 J for type A and type B series specimens respectively. The observed maximum indenter displacements at failure were the effect of material variations and composite configurations in the facesheet.

The Flow Field Downstream of a Dynamic Low Aspect Ratio Circular Cylinder: A Parametric Study

NASA Astrophysics Data System (ADS)

Gildersleeve, Samantha; Dan, Clingman; Amitay, Michael

2015-11-01

Flow past a static, low aspect ratio cylinder (pin) has shown the formation of vortical structures, namely the horseshoe and arch-type vortex. These vortical structures may have substantial effects in controlling flow separation over airfoils. In the present experiments, the flow field associated with a low aspect ratio cylinder as it interacts with a laminar boundary layer under static and dynamic conditions was investigated through a parametric study over a flat plate. As a result of the pin being actuated in the wall-normal direction, the structures formed in the wake of the pin were seen to be a strong function of actuation amplitude, driving frequency, and aspect ratio of the cylinder. The study was conducted at a Reynolds number of 1875, based on the local boundary layer thickness, with a free stream velocity of 10 m/s. SPIV data were collected for two aspect ratios of 0.75 and 1.125, actuation amplitudes of 6.7% and 16.7%, and driving frequencies of 175 Hz and 350 Hz. Results indicate that the presence and interactions between vortical structures are altered in comparison to the static case and suggest increased large-scale mixing when the pin is driven at the shedding frequency (350 Hz). Supported by the Boeing Company.

Results of application of automatic computation of static corrections on data from the South Banat Terrain

NASA Astrophysics Data System (ADS)

Milojević, Slavka; Stojanovic, Vojislav

2017-04-01

Due to the continuous development of the seismic acquisition and processing method, the increase of the signal/fault ratio always represents a current target. The correct application of the latest software solutions improves the processing results and justifies their development. A correct computation and application of static corrections represents one of the most important tasks in pre-processing. This phase is of great importance for further processing steps. Static corrections are applied to seismic data in order to compensate the effects of irregular topography, the difference between the levels of source points and receipt in relation to the level of reduction, of close to the low-velocity surface layer (weathering correction), or any reasons that influence the spatial and temporal position of seismic routes. The refraction statics method is the most common method for computation of static corrections. It is successful in resolving of both the long-period statics problems and determining of the difference in the statics caused by abrupt lateral changes in velocity in close to the surface layer. XtremeGeo FlatironsTM is a program whose main purpose is computation of static correction through a refraction statics method and allows the application of the following procedures: picking of first arrivals, checking of geometry, multiple methods for analysis and modelling of statics, analysis of the refractor anisotropy and tomography (Eikonal Tomography). The exploration area is located on the southern edge of the Pannonian Plain, in the plain area with altitudes of 50 to 195 meters. The largest part of the exploration area covers Deliblato Sands, where the geological structure of the terrain and high difference in altitudes significantly affects the calculation of static correction. Software XtremeGeo FlatironsTM has powerful visualization and tools for statistical analysis which contributes to significantly more accurate assessment of geometry close to the surface layers and therefore more accurately computed static corrections.

Static shape control for adaptive wings

NASA Astrophysics Data System (ADS)

Austin, Fred; Rossi, Michael J.; van Nostrand, William; Knowles, Gareth; Jameson, Antony

1994-09-01

A theoretical method was developed and experimentally validated, to control the static shape of flexible structures by employing internal translational actuators. A finite element model of the structure, without the actuators present, is employed to obtain the multiple-input, multiple-output control-system gain matrices for actuator-load control as well as actuator-displacement control. The method is applied to the quasistatic problem of maintaining an optimum-wing cross section during various transonic-cruise flight conditions to obtain significant reductions in the shock-induced drag. Only small, potentially achievable, adaptive modifications to the profile are required. The adaptive-wing concept employs actuators as truss elements of active ribs to reshape the wing cross section by deforming the structure. Finite element analyses of an adaptive-rib model verify the controlled-structure theory. Experiments on the model were conducted, and arbitrarily selected deformed shapes were accurately achieved.

Polarizability of acetanilide and RDX in the crystal: effect of molecular geometry

NASA Astrophysics Data System (ADS)

Tsiaousis, D.; Munn, R. W.; Smith, P. J.; Popelier, P. L. A.

2004-10-01

Density-functional theory with the B3LYP functional at the 6-311++G** level is used to calculate the dipole moment and the static polarizability for acetanilide and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) in their in-crystal structures. For acetanilide the dipole moment is 2{1}/{2}% larger than for the gas-phase structure and for RDX (where there is a gross geometry change) it is 15% larger. The polarizability for the in-crystal structure is smaller than for the gas-phase structure by 3% for both species, whereas the in-crystal effective optical polarizability is larger than the gas-phase static polarizability for both crystals. Hence, effects in addition to the molecular geometry change in the crystal must be considered in order to interpret the effective polarizability completely.

Dynamic Structure of a Molecular Liquid S0.5Cl0.5: Ab initio Molecular-Dynamics Simulations

NASA Astrophysics Data System (ADS)

Ohmura, Satoshi; Shimakura, Hironori; Kawakita, Yukinobu; Shimojo, Fuyuki; Yao, Makoto

2013-07-01

The static and dynamic structures of a molecular liquid S0.5Cl0.5 consisting of Cl--S--S--Cl (S2Cl2) type molecules are studied by means of ab initio molecular dynamics simulations. Both the calculated static and dynamic structure factors are in good agreement with experimental results. The dynamic structures are discussed based on van-Hove distinct correlation functions, molecular translational mean-square displacements (TMSD) and rotational mean-square displacements (RMSD). In the TMSD and RMSD, there are ballistic and diffusive regimes in the sub-picosecond and picosecond time regions, respectively. These time scales are consistent with the decay time observed experimentally. The interaction between molecules in the liquid is also discussed in comparison with that in another liquid chalcogen--halogen system Se0.5Cl0.5.

Plastic and Large-Deflection Analysis of Nonlinear Structures

NASA Technical Reports Server (NTRS)

Thomson, R. G.; Hayduk, R. J.; Robinson, M. P.; Durling, B. J.; Pifko, A.; Levine, H. S.; Armen, H. J.; Levy, A.; Ogilvie, P.

1982-01-01

Plastic and Large Deflection Analysis of Nonlinear Structures (PLANS) system is collection of five computer programs for finite-element static-plastic and large deflection analysis of variety of nonlinear structures. System considers bending and membrane stresses, general three-dimensional bodies, and laminated composites.

Effect of specific surface microstructures on substrate endothelialisation and thrombogenicity: Importance for stent design.

PubMed

Lutter, Christoph; Nothhaft, Matthias; Rzany, Alexander; Garlichs, Christoph D; Cicha, Iwona

2015-01-01

In coronary artery disease, highly stenosed arteries are frequently treated by stent implantation, which thereafter necessitates a dual-antiplatelet therapy (DAPT) in order to prevent stent-thrombosis. We hypothesized that specific patterns of microstructures on stents can accelerate endothelialisation thereby reducing their thrombogenicity and the DAPT duration. Differently designed, 2-5 μm high elevations or hollows were lithographically etched on silicon plates, subsequently coated with silicon carbide. Smooth silicon plates and bare metal substrates were used as controls. To assess attachment and growth of human umbilical vein endothelial cells under static or flow conditions, actin cytoskeleton was visualised with green phalloidin. Endothelial migration was assessed in a modified barrier assay. To investigate surface thrombogenicity, platelets were incubated on the structured surfaces in static and flow conditions, and visualised with fluorescein-conjugated P-selectin antibody. Images were taken with incident-light fluorescent microscope for non-transparent objects. Compared to smooth surface, flat cubic elevations (5 μm edge length) improved endothelial cell attachment and growth under static and dynamic conditions, whereas smaller, spiky structures (2 μm edge length) had a negative influence on endothelialisation. Endothelial cell migration was fastest on flat cubic elevations, hollows, and smooth surfaces, whereas spiky structures and bare metal had a negative effect on endothelial migration. Thrombogenicity assays under static and flow conditions showed that platelet adhesion was reduced on the flat elevations and the smooth surface, as compared to the spiky structures, the hollow design and the bare metal substrates. Surface microstructures strongly influence endothelialisation of substrates. Designing stents with surface topography which accelerates endothelialisation and reduces thrombogenicity may be of clinical benefit by improving the safety profile of coronary interventions.

Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 4: Full scale ground test

NASA Technical Reports Server (NTRS)

Jackson, A. C.; Dorwald, F.

1982-01-01

The ground tests conducted on the advanced composite vertical fin (ACVF) program are described. The design and fabrication of the test fixture and the transition structure, static test of Ground Test Article (GTA) No. 1, rework of GTA No. 2, and static, damage tolerance, fail-safe and residual strength tests of GTA No. 2 are described.

Weak interactions in Graphane/BN systems under static electric fields—A periodic ab-initio study.

PubMed

Steinkasserer, Lukas Eugen Marsoner; Gaston, Nicola; Paulus, Beate

2015-04-21

Ab-initio calculations via periodic Hartree-Fock (HF) and local second-order Møller-Plesset perturbation theory (LMP2) are used to investigate the adsorption properties of combined Graphane/boron nitride systems and their response to static electric fields. It is shown how the latter can be used to alter both structural as well as electronic properties of these systems.

Static and Fatigue Strength Evaluations for Bolted Composite/Steel Joints for Heavy Vehicle Chassis Components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Xin; Stephens, Elizabeth V.; Herling, Darrell R.

2004-09-14

In May 2003, ORNL and PNNL began collaboration on a four year research effort focused on developing joining techniques to overcome the technical issues associated with joining lightweight materials in heavy vehicles. The initial focus of research is the development and validation of joint designs for a composite structural member attached to a metal member that satisfy the structural requirements both economically and reliably. Huck-bolting is a common joining method currently used in heavy truck chassis structures. The initial round of testing was conducted to establish a performance benchmark by evaluating the static and fatigue behavior of an existing steel/steelmore » chassis joint at the single huck-bolt level. Both tension and shear loading conditions were considered, and the resulting static and fatigue strengths will be used to guide the joint design for a replacement composite/steel joint. A commercially available, pultruded composite material was chosen to study the generic issues related to composite/steel joints. Extren is produced by STRONGWELL, and it is a combination of fiberglass reinforcement and thermosetting polyester or vinyl ester resin systems. Extren sheets of 3.2 mm thick were joined to 1.4 mm SAE1008 steel sheets with a standard grade 5 bolt with 6.35 mm diameter. Both tension and shear loading modes were considered for the single hybrid joint under static and fatigue loading conditions. Since fiberglass reinforced thermoset polymer composites are a non-homogenous material, their strengths and behavior are dependent upon the design of the composite and reinforcement. The Extren sheet stock was cut along the longitudinal direction to achieve maximum net-section strength. The effects of various manufacturing factors and operational conditions on the static and fatigue strength of the hybrid joint were modeled and experimentally verified. It was found that loading mode and washer size have significant influence on the static and fatigue strength of the hybrid joint. The effect of different fatigue test frequencies on the sample temperature and the resulting fatigue life was also examined.« less

Static strain and vibration characteristics of a metal semimonocoque helicopter tail cone of moderate size

NASA Technical Reports Server (NTRS)

Bielawa, Richard L.; Hefner, Rachel E.; Castagna, Andre

1991-01-01

The results are presented of an analytic and experimental research program involving a Sikorsky S-55 helicopter tail cone directed ultimately to the improved structural analysis of airframe substructures typical of moderate sized helicopters of metal semimonocoque construction. Experimental static strain and dynamic shake-testing measurements are presented. Correlation studies of each of these tests with a PC-based finite element analysis (COSMOS/M) are described. The tests included static loadings at the end of the tail cone supported in the cantilever configuration as well as vibrational shake-testing in both the cantilever and free-free configurations.

Minimum constitutive relation error based static identification of beams using force method

NASA Astrophysics Data System (ADS)

Guo, Jia; Takewaki, Izuru

2017-05-01

A new static identification approach based on the minimum constitutive relation error (CRE) principle for beam structures is introduced. The exact stiffness and the exact bending moment are shown to make the CRE minimal for given displacements to beam damages. A two-step substitution algorithm—a force-method step for the bending moment and a constitutive-relation step for the stiffness—is developed and its convergence is rigorously derived. Identifiability is further discussed and the stiffness in the undeformed region is found to be unidentifiable. An extra set of static measurements is complemented to remedy the drawback. Convergence and robustness are finally verified through numerical examples.

Molecular Static Third-Order Polarizabilities of Carbon-Cage Fullerenes and their Correlation with Three Geometric Parameters: Group Order, Aromaticity, and Size

NASA Technical Reports Server (NTRS)

Moore, Craig E.; Cardelino, Beatriz H.; Frazier, Donald O.; Niles, Julian; Wang, Xian-Qiang

1997-01-01

Calculations were performed on the valence contribution to the static molecular third-order polarizabilities (gamma) of thirty carbon-cage fullerenes (C60, C70, five isomers of C78, and twenty-three isomers of C84). The molecular structures were obtained from B3LYP/STO-3G calculations. The values of the tensor elements and an associated numerical uncertainty were obtained using the finite-field approach and polynomial expansions of orders four to eighteen of polarization versus static electric field data. The latter information was obtained from semiempirical calculations using the AM1 hamiltonian.

Static and dynamic crush testing and analysis of a rail vehicle corner structural element

DOT National Transportation Integrated Search

1999-11-01

This paper presents the results of an experimental study to establish the strength and energy absorption capability of cab car rail vehicle corner structures built to current strength requirements and for structures modified to carry higher loads and...

14 CFR 25.307 - Proof of structure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... load tests may be inadequate. (b)-(c) [Reserved] (d) When static or dynamic tests are used to show... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... condition. Structural analysis may be used only if the structure conforms to that for which experience has...

14 CFR 25.307 - Proof of structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... load tests may be inadequate. (b)-(c) [Reserved] (d) When static or dynamic tests are used to show... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... condition. Structural analysis may be used only if the structure conforms to that for which experience has...

14 CFR 25.307 - Proof of structure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... load tests may be inadequate. (b)-(c) [Reserved] (d) When static or dynamic tests are used to show... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... condition. Structural analysis may be used only if the structure conforms to that for which experience has...

14 CFR 25.307 - Proof of structure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... load tests may be inadequate. (b)-(c) [Reserved] (d) When static or dynamic tests are used to show... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... condition. Structural analysis may be used only if the structure conforms to that for which experience has...

14 CFR 25.307 - Proof of structure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... load tests may be inadequate. (b)-(c) [Reserved] (d) When static or dynamic tests are used to show... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... condition. Structural analysis may be used only if the structure conforms to that for which experience has...

Spherical harmonics analysis of surface density fluctuations of spherical ionic SDS and nonionic C12E8 micelles: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Yoshii, Noriyuki; Nimura, Yuki; Fujimoto, Kazushi; Okazaki, Susumu

2017-07-01

The surface structure and its fluctuation of spherical micelles were investigated using a series of density correlation functions newly defined by spherical harmonics and Legendre polynomials based on the molecular dynamics calculations. To investigate the influence of head-group charges on the micelle surface structure, ionic sodium dodecyl sulfate and nonionic octaethyleneglycol monododecylether (C12E8) micelles were investigated as model systems. Large-scale density fluctuations were observed for both micelles in the calculated surface static structure factor. The area compressibility of the micelle surface evaluated by the surface static structure factor was tens-of-times larger than a typical value of a lipid membrane surface. The structural relaxation time, which was evaluated from the surface intermediate scattering function, indicates that the relaxation mechanism of the long-range surface structure can be well described by the hydrostatic approximation. The density fluctuation on the two-dimensional micelle surface has similar characteristics to that of three-dimensional fluids near the critical point.

Spherical harmonics analysis of surface density fluctuations of spherical ionic SDS and nonionic C12E8 micelles: A molecular dynamics study.

PubMed

Yoshii, Noriyuki; Nimura, Yuki; Fujimoto, Kazushi; Okazaki, Susumu

2017-07-21

The surface structure and its fluctuation of spherical micelles were investigated using a series of density correlation functions newly defined by spherical harmonics and Legendre polynomials based on the molecular dynamics calculations. To investigate the influence of head-group charges on the micelle surface structure, ionic sodium dodecyl sulfate and nonionic octaethyleneglycol monododecylether (C 12 E 8 ) micelles were investigated as model systems. Large-scale density fluctuations were observed for both micelles in the calculated surface static structure factor. The area compressibility of the micelle surface evaluated by the surface static structure factor was tens-of-times larger than a typical value of a lipid membrane surface. The structural relaxation time, which was evaluated from the surface intermediate scattering function, indicates that the relaxation mechanism of the long-range surface structure can be well described by the hydrostatic approximation. The density fluctuation on the two-dimensional micelle surface has similar characteristics to that of three-dimensional fluids near the critical point.

Static and dynamic response of a sandwich structure under axial compression

NASA Astrophysics Data System (ADS)

Ji, Wooseok

This thesis is concerned with a combined experimental and theoretical investigation of the static and dynamic response of an axially compressed sandwich structure. For the static response problem of sandwich structures, a two-dimensional mechanical model is developed to predict the global and local buckling of a sandwich beam, using classical elasticity. The face sheet and the core are assumed as linear elastic orthotropic continua in a state of planar deformation. General buckling deformation modes (periodic and non-periodic) of the sandwich beam are considered. On the basis of the model developed here, validation and accuracy of several previous theories are discussed for different geometric and material properties of a sandwich beam. The appropriate incremental stress and conjugate incremental finite strain measure for the instability problem of the sandwich beam, and the corresponding constitutive model are addressed. The formulation used in the commercial finite element package is discussed in relation to the formulation adopted in the theoretical derivation. The Dynamic response problem of a sandwich structure subjected to axial impact by a falling mass is also investigated. The dynamic counterpart of the celebrated Euler buckling problem is formulated first and solved by considering the case of a slender column that is impacted by a falling mass. A new notion, that of the time to buckle, "t*" is introduced, which is the corresponding critical quantity analogous to the critical load in static Euler buckling. The dynamic bifurcation buckling analysis is extended to thick sandwich structures using an elastic foundation model. A comprehensive set of impact test results of sandwich columns with various configurations are presented. Failure mechanisms and the temporal history of how a sandwich column responds to axial impact are discussed through the experimental results. The experimental results are compared against analytical dynamic buckling studies and finite element based simulation of the impact event.

Development of highly reliable static random access memory for 40-nm embedded split gate-MONOS flash memory

NASA Astrophysics Data System (ADS)

Okamoto, Shin-ichi; Maekawa, Kei-ichi; Kawashima, Yoshiyuki; Shiba, Kazutoshi; Sugiyama, Hideki; Inoue, Masao; Nishida, Akio

2015-04-01

High quality static random access memory (SRAM) for 40-nm embedded MONOS flash memory with split gate (SG-MONOS) was developed. Marginal failure, which results in threshold voltage/drain current tailing and outliers of SRAM transistors, occurs when using a conventional SRAM structure. These phenomena can be explained by not only gate depletion but also partial depletion and percolation path formation in the MOS channel. A stacked poly-Si gate structure can suppress these phenomena and achieve high quality SRAM without any defects in the 6σ level and with high affinity to the 40-nm SG-MONOS process was developed.

Development of technology for the fabrication of reliable laminar flow control panels on subsonic transports

NASA Technical Reports Server (NTRS)

1976-01-01

The feasibility of using porous composite materials (Kevlar, Doweave, and Leno Weave) as lightweight, efficient laminar flow control (LFC) surface materials is compared to the metallic 319L stainless Dynapore surfaces and electron beam drilled composite surfaces. Areas investigated include: (1) selection of the LFC-suitable surface materials, structural materials, and fabrication techniques for the LFC aircraft skins; (2) aerodynamic static air flow test results in terms of pressure drop through the LFC panel and the corresponding effective porosity; (3) structural design definition and analyses of the panels, and (4) contamination effects on static drop and effective porosity. Conclusions are presented and discussed.

Instability of meridional axial system in f( R) gravity

NASA Astrophysics Data System (ADS)

Sharif, M.; Yousaf, Z.

2015-05-01

We analyze the dynamical instability of a non-static reflection axial stellar structure by taking into account the generalized Euler equation in metric f( R) gravity. Such an equation is obtained by contracting the Bianchi identities of the usual anisotropic and effective stress-energy tensors, which after using a radial perturbation technique gives a modified collapse equation. In the realm of the gravity model, we investigate instability constraints at Newtonian and post-Newtonian approximations. We find that the instability of a meridional axial self-gravitating system depends upon the static profile of the structure coefficients, while f( R) extra curvature terms induce the stability of the evolving celestial body.

Implementation of structural response sensitivity calculations in a large-scale finite-element analysis system

NASA Technical Reports Server (NTRS)

Giles, G. L.; Rogers, J. L., Jr.

1982-01-01

The methodology used to implement structural sensitivity calculations into a major, general-purpose finite-element analysis system (SPAR) is described. This implementation includes a generalized method for specifying element cross-sectional dimensions as design variables that can be used in analytically calculating derivatives of output quantities from static stress, vibration, and buckling analyses for both membrane and bending elements. Limited sample results for static displacements and stresses are presented to indicate the advantages of analytically calculating response derivatives compared to finite difference methods. Continuing developments to implement these procedures into an enhanced version of SPAR are also discussed.

Manufacturing technology of integrated textile-based sensor networks for in situ monitoring applications of composite wind turbine blades

NASA Astrophysics Data System (ADS)

Haentzsche, Eric; Mueller, Ralf; Huebner, Matthias; Ruder, Tristan; Unger, Reimar; Nocke, Andreas; Cherif, Chokri

2016-10-01

Based on in situ strain sensors consisting of piezo-resistive carbon filament yarns (CFYs), which have been successfully integrated into textile reinforcement structures during their textile-technological manufacturing process, a continuous load of fibre-reinforced plastic (FRP) components has been realised. These sensors are also suitable for structural health monitoring (SHM) applications. The two-dimensional sensor layout is made feasible by the usage of a modular warp yarn path manipulation unit. Using a functional model of a small wind turbine blade in thermoset composite design, the sensor function for basic SHM applications (e.g. static load monitoring) are demonstrated. Any mechanical loads along the pressure or suction side of the wind turbine blade can be measured and calculated via a correlative change in resistance of the CFYs within the textile reinforcement plies. Performing quasi-static load tests on both tensile specimen and full-scale wind turbine blade, elementary results have been obtained concerning electro-mechanical behaviour and spatial resolution of global and even local static stresses according to the CFY sensor integration length. This paper demonstrates the great potential of textile-based and textile-technological integrated sensors in reinforcement structures for future SHM applications of FRPs.

A review of wave celerity in frictionless and axisymmetrical steel-lined pressure tunnels

NASA Astrophysics Data System (ADS)

Hachem, F. E.; Schleiss, A. J.

2011-02-01

Generally applicable approaches for estimating the “quasi-static”, which means without fluid-structure interaction and frequency-dependent water-hammer wave speed in steel-lined pressure tunnels are analyzed. The external constraints and assumptions of these approaches are discussed in detail. The reformulated formulas are then compared to commonly used expressions. Some special cases of wave speed calculation such as unlined pressure tunnels and open-air penstocks are investigated. The quasi-static wave speed is significantly influenced by the state of the backfill concrete and the near-field rock zone (cracked or uncracked). In the case when these two layers are cracked, the quasi-static wave speed is overestimated in between 1% and 8% compared to uncracked concrete and near-field rock layers. Depending on the stiffness of steel liner and penstock, the fluid-structure interaction leads to significant difference in wave speeds values. Compared to the quasi-static case, the fluid-structure interaction approach, applied to steel-lined tunnels, results up to 13% higher wave speed values in the high-frequency range (higher than 600 Hz) and up to 150% lower values for frequencies between 150 and 300 Hz in the considered test case.

Supporting Structures for Flat Solar-Cell Arrays

NASA Technical Reports Server (NTRS)

Wilson, A. H.

1986-01-01

Strong supporting structures for flat solar photovoltaic arrays built with such commonly available materials as wood and galvanized steel sheet. Structures resist expected static loads from snow and ice as well as dynamic loads from winds and even Earthquake vibrations. Supporting structure uses inexpensive materials. Parts prefabricated to minimize assembly work in field.

Dynamic Risk Assessment of Sexual Offenders: Validity and Dimensional Structure of the Stable-2007.

PubMed

Etzler, Sonja; Eher, Reinhard; Rettenberger, Martin

2018-02-01

In this study, the predictive and incremental validity of the Stable-2007 beyond the Static-99 was evaluated in an updated sample of N = 638 adult male sexual offenders followed-up for an average of M = 8.2 years. Data were collected at the Federal Evaluation Center for Violent and Sexual Offenders (FECVSO) in Austria within a prospective-longitudinal research design. Scores and risk categories of the Static-99 (AUC = .721; p < .001) and of the Stable-2007 (AUC = .623, p = .005) were found to be significantly related to sexual recidivism. The Stable-2007 risk categories contributed incrementally to the prediction of sexual recidivism beyond the Static-99. Analyzing the dimensional structure of the Stable-2007 yielded three factors, named Antisociality, Sexual Deviance, and Hypersexuality. Antisociality and Sexual Deviance were significant predictors for sexual recidivism. Sexual Deviance was negatively associated with non-sexual violent recidivism. Comparisons with latent dimensions of other risk assessment instruments are made and implications for applied risk assessment are discussed.

Effect of structural factors on mechanical properties of the magnesium alloy Ma2-1 under quasi-static and high strain rate deformation conditions

NASA Astrophysics Data System (ADS)

Garkushin, G. V.; Razorenov, S. V.; Krasnoveikin, V. A.; Kozulin, A. A.; Skripnyak, V. A.

2015-02-01

The elastic limit and tensile strength of deformed magnesium alloys Ma2-1 with different structures and textures were measured with the aim of finding a correlation between the spectrum of defects in the material and the resistance to deformation and fracture under quasi-static and dynamic loading conditions. The studies were performed using specimens in the as-received state after high-temperature annealing and specimens subjected to equal-channel angular pressing at a temperature of 250°C. The anisotropy of strength characteristics of the material after shock compression with respect to the direction of rolling of the original alloy was investigated. It was shown that, in contrast to the quasi-static loading conditions, under the shock wave loading conditions, the elastic limit and tensile strength of the magnesium alloy Ma2-1 after equal-channel angular pressing decrease as compared to the specimens in the as-received state.

Interactive Structure (EUCLID) For Static And Dynamic Representation Of Human Body

NASA Astrophysics Data System (ADS)

Renaud, Ch.; Steck, R.

1983-07-01

A specific software (EUCLID) for static and dynamic representation of human models is described. The data processing system is connected with ERGODATA and used in interactive mode by intrinsic or specific functions. More or less complex representations in 3-D view of models of the human body are developed. Biostereometric and conventional anthropometric raw data from the data bank are processed for different applications in ergonomy.

High temperature static strain measurement with an electrical resistance strain gage

NASA Technical Reports Server (NTRS)

Lei, Jih-Fen

1992-01-01

An electrical resistance strain gage that can supply accurate static strain measurement for NASP application is being developed both in thin film and fine wire forms. This gage is designed to compensate for temperature effects on substrate materials with a wide range of thermal expansion coefficients. Some experimental results of the wire gage tested on one of the NASP structure materials, i.e., titanium matrix composites, are presented.

Static aeroelastic behavior of a subsonic plate wing

NASA Astrophysics Data System (ADS)

Berci, M.

2017-07-01

The static aeroelastic behavior of a subsonic plate wing is here described by semi-analytical means. Within a generalised modal formulation, any distribution of the plate's properties is allowed. Modified strip theory is employed for the aerodynamic modelling and a linear aeroelastic model is eventually derived. Numerical results are then shown for the plate's aeroelastic stability in terms of divergence speed, with respect to the most relevant aero-structural parameters.

MHD Simulation for Investigating the Dynamic State Transition Responsible for a Solar Eruption in Active Region 12158

NASA Astrophysics Data System (ADS)

Lee, Hwanhee; Magara, Tetsuya

2018-06-01

We present a magnetohydrodynamic model of solar eruption based on the dynamic state transition from the quasi-static state to the eruptive state of an active region (AR) magnetic field. For the quasi-static state before an eruption, we consider the existence of a slow solar wind originating from an AR, which may continuously make the AR magnetic field deviate from mechanical equilibrium. In this model, we perform a three-dimensional magnetohydrodynamic simulation of AR 12158 producing a coronal mass ejection, where the initial magnetic structure of the simulation is given by a nonlinear force-free field derived from an observed photospheric vector magnetic field. We then apply a pressure-driven outflow to the upper part of the magnetic structure to achieve a quasi-static pre-eruptive state. The simulation shows that the eruptive process observed in this AR may be caused by the dynamic state transition of an AR magnetic field, which is essentially different from the destabilization of a static magnetic field. The dynamic state transition is determined from the shape evolution of the magnetic field line according to the κH-mechanism. This work demonstrates how the mechanism works to produce a solar eruption in the dynamic solar corona governed by the gravitational field and the continuous outflows of solar wind.

Static Strength of Adhesively-bonded Woven Fabric Kenaf Composite Plates

NASA Astrophysics Data System (ADS)

Hilton, Ahmad; Lee, Sim Yee; Supar, Khairi

2017-06-01

Natural fibers are potentially used as reinforcing materials and combined with epoxy resin as matrix system to form a superior specific strength (or stiffness) materials known as composite materials. The advantages of implementing natural fibers such as kenaf fibers are renewable, less hazardous during fabrication and handling process; and relatively cheap compared to synthetic fibers. The aim of current work is to conduct a parametric study on static strength of adhesively bonded woven fabric kenaf composite plates. Fabrication of composite panels were conducted using hand lay-up techniques, with variation of stacking sequence, over-lap length, joint types and lay-up types as identified in testing series. Quasi-static testing was carried out using mechanical testing following code of practice. Load-displacement profiles were analyzed to study its structural response prior to ultimate failures. It was found that cross-ply lay-up demonstrates better static strength compared to quasi-isotropic lay-up counterparts due to larger volume of 0° plies exhibited in cross-ply lay-up. Consequently, larger overlap length gives better joining strength, as expected, however this promotes to weight penalty in the joining structure. Most samples showed failures within adhesive region known as cohesive failure modes, however, few sample demonstrated interface failure. Good correlations of parametric study were found and discussed in the respective section.

Fatigue performance of variable message sign & luminaire support structures : volume II, fatigue related wind loads on highway support structures.

DOT National Transportation Integrated Search

1998-05-01

In Order to determine equivalent static pressures for fatigue loads on cantilevered highway support structures a : cantilevered Variable Message Sign(VMS) located along Interstate westbound at mile marker 48.5 in northern : New Jersey was continuousl...

Fatigue performance of variable message sign & luminaire support structures : volume I, fatigue related wind loads on highway support structures

DOT National Transportation Integrated Search

1998-04-01

In Order to determine equivalent static pressures for fatigue loads on cantilevered highway support structures a : cantilevered Variable Message Sign(VMS) located along Interstate westbound at mile marker 48.5 in northern : New Jersey was continuousl...

Quasi-Static Probabilistic Structural Analyses Process and Criteria

NASA Technical Reports Server (NTRS)

Goldberg, B.; Verderaime, V.

1999-01-01

Current deterministic structural methods are easily applied to substructures and components, and analysts have built great design insights and confidence in them over the years. However, deterministic methods cannot support systems risk analyses, and it was recently reported that deterministic treatment of statistical data is inconsistent with error propagation laws that can result in unevenly conservative structural predictions. Assuming non-nal distributions and using statistical data formats throughout prevailing stress deterministic processes lead to a safety factor in statistical format, which integrated into the safety index, provides a safety factor and first order reliability relationship. The embedded safety factor in the safety index expression allows a historically based risk to be determined and verified over a variety of quasi-static metallic substructures consistent with the traditional safety factor methods and NASA Std. 5001 criteria.

Selection of actuator locations for static shape control of large space structures by heuristic integer programing

NASA Technical Reports Server (NTRS)

Haftka, R. T.; Adelman, H. M.

1984-01-01

Orbiting spacecraft such as large space antennas have to maintain a highly accurate space to operate satisfactorily. Such structures require active and passive controls to mantain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.

Electromagnon in the Y-type hexaferrite BaSrCoZnFe11AlO22

NASA Astrophysics Data System (ADS)

Vít, Jakub; Kadlec, Filip; Kadlec, Christelle; Borodavka, Fedir; Chai, Yi Sheng; Zhai, Kun; Sun, Young; Kamba, Stanislav

2018-04-01

We investigated static and dynamic magnetoelectric properties of single crystalline BaSrCoZnFe11AlO22 , which is a room-temperature multiferroic with Y-type hexaferrite crystal structure. Below 300 K, a purely electric-dipole-active electromagnon at ≈1.2 THz with the electric polarization oscillating along the hexagonal axis was observed by THz and Raman spectroscopies. We investigated the behavior of the electromagnon with applied dc magnetic field and linked its properties to static measurements of the magnetic structure. Our analytical calculations determined selection rules for electromagnons activated by the magnetostriction mechanism in various magnetic structures of Y-type hexaferrite. Comparison with our experiment supports that the electromagnon is indeed activated by the magnetostriction mechanism involving spin vibrations along the hexagonal axis.

Structural design significance of tension-tension fatigue data on composites

NASA Technical Reports Server (NTRS)

Grimes, G. C.

1977-01-01

Constant cycle tension-tension fatigue and related static tension data have been generated on six single composite material/orientation combinations and twenty-one hybrid composite material/orientation combinations. Anomalies are related to the temperature rise and stopped interval creep, whereas endurance limit stresses (runouts) are associated with static proportional limit values, when they occur, and internal damage. The significance of these room temperature-dry data on the design allowables and weight of aerodynamic structueres is discussed. Such structures are helicopter rotor blades and wing and horizontal stabilizer lower surfaces. Typical criteria for turning these data into preliminary allowables are shown, as are examples of such allowables developed from the data. These values are then compared to those that might be used if the structures were made of metal.

Operational experience with VAWT blades. [structural performance

NASA Technical Reports Server (NTRS)

Sullivan, W. N.

1979-01-01

The structural performance of 17 meter diameter wind turbine rotors is discussed. Test results for typical steady and vibratory stress measurements are summarized along with predicted values of stress based on a quasi-static finite element model.

An ab initio study of the structure and dynamics of bulk liquid Cd and its liquid-vapor interface.

PubMed

Calderín, L; González, L E; González, D J

2013-02-13

Several static and dynamic properties of bulk liquid Cd at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation which points to a small positive dispersion. Results are also reported for several transport coefficients. Additional simulations have also been performed at a slightly higher temperature in order to study the structure of the free liquid surface. The ionic density profile shows an oscillatory behavior with two different wavelengths, as the spacing between the outer and first inner layer is different from that between the other inner layers. The calculated reflectivity shows a marked maximum whose origin is related to the surface layering, along with a shoulder located at a much smaller wavevector transfer.

Static characteristics design of hydrostatic guide-ways based on fluid-structure interactions

NASA Astrophysics Data System (ADS)

Lin, Shuo; Yin, YueHong

2016-10-01

With the raising requirements in micro optical systems, the available machines become hard to achieve the process dynamic and accuracy in all aspects. This makes compact design based on fluid/structure interactions (FSI) important. However, there is a difficulty in studying FSI with oil film as fluid domain. This paper aims at static characteristic design of a hydrostatic guide-way with capillary restrictors based on FSI. The pressure distribution of the oil film land is calculated by solving the Reynolds-equation with Galerkin technique. The deformation of structure is calculated by commercial FEM software, MSC. Nastran. A matlab program is designed to realize the coupling progress by modifying the load boundary in the submitting file and reading the deformation result. It's obvious that the stiffness of the hydrostatic bearing decreases with the weakening of the bearing structure. This program is proposed to make more precise prediction of bearing stiffness.

Self-adaptive predictor-corrector algorithm for static nonlinear structural analysis

NASA Technical Reports Server (NTRS)

Padovan, J.

1981-01-01

A multiphase selfadaptive predictor corrector type algorithm was developed. This algorithm enables the solution of highly nonlinear structural responses including kinematic, kinetic and material effects as well as pro/post buckling behavior. The strategy involves three main phases: (1) the use of a warpable hyperelliptic constraint surface which serves to upperbound dependent iterate excursions during successive incremental Newton Ramphson (INR) type iterations; (20 uses an energy constraint to scale the generation of successive iterates so as to maintain the appropriate form of local convergence behavior; (3) the use of quality of convergence checks which enable various self adaptive modifications of the algorithmic structure when necessary. The restructuring is achieved by tightening various conditioning parameters as well as switch to different algorithmic levels to improve the convergence process. The capabilities of the procedure to handle various types of static nonlinear structural behavior are illustrated.

Brownian dynamics of sterically-stabilized colloidal suspensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

TeGrotenhuis, W.E.; Radke, C.J.; Denn, M.M.

1994-02-01

One application where microstructure plays a critical role is in the production of specialty ceramics, where colloidal suspensions act as precursors; here the microstructure influences the structural, thermal, optical and electrical properties of the ceramic products. Using Brownian dynamics, equilibrium and dynamic properties are calculated for colloidal suspensions that are stabilized through the Milner, Witten and Cates (1988) steric potential. Results are reported for osmotic pressures, radial distributions functions, static structure factors, and self-diffusion coefficients. The sterically-stabilized systems are also approximated by equivalent hard spheres, with good agreement for osmotic pressure and long-range structure. The suitability of the potential tomore » model the behavior of a real system is explored by comparing static structure factors calculated from Brownian dynamics simulations to those measured using SANS. Finally, the effects of Hamaker and hydrodynamic forces on calculated properties are investigated.« less

MSC/NASTRAN DMAP Alter Used for Closed-Form Static Analysis With Inertia Relief and Displacement-Dependent Loads

NASA Technical Reports Server (NTRS)

1996-01-01

Solving for the displacements of free-free coupled systems acted upon by static loads is a common task in the aerospace industry. Often, these problems are solved by static analysis with inertia relief. This technique allows for a free-free static analysis by balancing the applied loads with the inertia loads generated by the applied loads. For some engineering applications, the displacements of the free-free coupled system induce additional static loads. Hence, the applied loads are equal to the original loads plus the displacement-dependent loads. A launch vehicle being acted upon by an aerodynamic loading can have such applied loads. The final displacements of such systems are commonly determined with iterative solution techniques. Unfortunately, these techniques can be time consuming and labor intensive. Because the coupled system equations for free-free systems with displacement-dependent loads can be written in closed form, it is advantageous to solve for the displacements in this manner. Implementing closed-form equations in static analysis with inertia relief is analogous to implementing transfer functions in dynamic analysis. An MSC/NASTRAN (MacNeal-Schwendler Corporation/NASA Structural Analysis) DMAP (Direct Matrix Abstraction Program) Alter was used to include displacement-dependent loads in static analysis with inertia relief. It efficiently solved a common aerospace problem that typically has been solved with an iterative technique.

A 'Quad-Disc' static pressure probe for measurement in adverse atmospheres - With a comparative review of static pressure probe designs

NASA Astrophysics Data System (ADS)

Nishiyama, Randall T.; Bedard, Alfred J., Jr.

1991-09-01

There are many areas of need for accurate measurements of atmospheric static pressure. These include observations of surface meteorology, airport altimeter settings, pressure distributions around buildings, moving measurement platforms, as well as basic measurements of fluctuating pressures in turbulence. Most of these observations require long-term observations in adverse environments (e.g., rain, dust, or snow). Currently, many pressure measurements are made, of necessity, within buildings, thus involving potential errors of several millibars in mean pressure during moderate winds, accompanied by large fluctuating pressures induced by the structure. In response to these needs, a 'Quad-Disk' pressure probe for continuous, outdoor monitoring purposes was designed which is inherently weather-protected. This Quad-Disk probe has the desirable features of omnidirectional response and small error in pitch. A review of past static pressure probes contrasts design approaches and capabilities.

Development of GENOA Progressive Failure Parallel Processing Software Systems

NASA Technical Reports Server (NTRS)

Abdi, Frank; Minnetyan, Levon

1999-01-01

A capability consisting of software development and experimental techniques has been developed and is described. The capability is integrated into GENOA-PFA to model polymer matrix composite (PMC) structures. The capability considers the physics and mechanics of composite materials and structure by integration of a hierarchical multilevel macro-scale (lamina, laminate, and structure) and micro scale (fiber, matrix, and interface) simulation analyses. The modeling involves (1) ply layering methodology utilizing FEM elements with through-the-thickness representation, (2) simulation of effects of material defects and conditions (e.g., voids, fiber waviness, and residual stress) on global static and cyclic fatigue strengths, (3) including material nonlinearities (by updating properties periodically) and geometrical nonlinearities (by Lagrangian updating), (4) simulating crack initiation. and growth to failure under static, cyclic, creep, and impact loads. (5) progressive fracture analysis to determine durability and damage tolerance. (6) identifying the percent contribution of various possible composite failure modes involved in critical damage events. and (7) determining sensitivities of failure modes to design parameters (e.g., fiber volume fraction, ply thickness, fiber orientation. and adhesive-bond thickness). GENOA-PFA progressive failure analysis is now ready for use to investigate the effects on structural responses to PMC material degradation from damage induced by static, cyclic (fatigue). creep, and impact loading in 2D/3D PMC structures subjected to hygrothermal environments. Its use will significantly facilitate targeting design parameter changes that will be most effective in reducing the probability of a given failure mode occurring.

Numerical simulations (2D) on the influence of pre-existing local structures and seismic source characteristics in earthquake-volcano interactions

NASA Astrophysics Data System (ADS)

Farías, Cristian; Galván, Boris; Miller, Stephen A.

2017-09-01

Earthquake triggering of hydrothermal and volcanic systems is ubiquitous, but the underlying processes driving these systems are not well-understood. We numerically investigate the influence of seismic wave interaction with volcanic systems simulated as a trapped, high-pressure fluid reservoir connected to a fluid-filled fault system in a 2-D poroelastic medium. Different orientations and earthquake magnitudes are studied to quantify dynamic and static stress, and pore pressure changes induced by a seismic event. Results show that although the response of the system is mainly dominated by characteristics of the radiated seismic waves, local structures can also play an important role on the system dynamics. The fluid reservoir affects the seismic wave front, distorts the static overpressure pattern induced by the earthquake, and concentrates the kinetic energy of the incoming wave on its boundaries. The static volumetric stress pattern inside the fault system is also affected by the local structures. Our results show that local faults play an important role in earthquake-volcanic systems dynamics by concentrating kinetic energy inside and acting as wave-guides that have a breakwater-like behavior. This generates sudden changes in pore pressure, volumetric expansion, and stress gradients. Local structures also influence the regional Coulomb yield function. Our results show that local structures affect the dynamics of volcanic and hydrothermal systems, and should be taken into account when investigating triggering of these systems from nearby or distant earthquakes.

Comparative static curing versus dynamic curing on tablet coating structures.

PubMed

Gendre, Claire; Genty, Muriel; Fayard, Barbara; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

2013-09-10

Curing is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24h of static curing and 4h of dynamic curing, both performed at 60°C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Moment measurements in dynamic and quasi-static spine segment testing using eccentric compression are susceptible to artifacts based on loading configuration.

PubMed

Van Toen, Carolyn; Carter, Jarrod W; Oxland, Thomas R; Cripton, Peter A

2014-12-01

The tolerance of the spine to bending moments, used for evaluation of injury prevention devices, is often determined through eccentric axial compression experiments using segments of the cadaver spine. Preliminary experiments in our laboratory demonstrated that eccentric axial compression resulted in "unexpected" (artifact) moments. The aim of this study was to evaluate the static and dynamic effects of test configuration on bending moments during eccentric axial compression typical in cadaver spine segment testing. Specific objectives were to create dynamic equilibrium equations for the loads measured inferior to the specimen, experimentally verify these equations, and compare moment responses from various test configurations using synthetic (rubber) and human cadaver specimens. The equilibrium equations were verified by performing quasi-static (5 mm/s) and dynamic experiments (0.4 m/s) on a rubber specimen and comparing calculated shear forces and bending moments to those measured using a six-axis load cell. Moment responses were compared for hinge joint, linear slider and hinge joint, and roller joint configurations tested at quasi-static and dynamic rates. Calculated shear force and bending moment curves had similar shapes to those measured. Calculated values in the first local minima differed from those measured by 3% and 15%, respectively, in the dynamic test, and these occurred within 1.5 ms of those measured. In the rubber specimen experiments, for the hinge joint (translation constrained), quasi-static and dynamic posterior eccentric compression resulted in flexion (unexpected) moments. For the slider and hinge joints and the roller joints (translation unconstrained), extension ("expected") moments were measured quasi-statically and initial flexion (unexpected) moments were measured dynamically. In the cadaver experiments with roller joints, anterior and posterior eccentricities resulted in extension moments, which were unexpected and expected, for those configurations, respectively. The unexpected moments were due to the inertia of the superior mounting structures. This study has shown that eccentric axial compression produces unexpected moments due to translation constraints at all loading rates and due to the inertia of the superior mounting structures in dynamic experiments. It may be incorrect to assume that bending moments are equal to the product of compression force and eccentricity, particularly where the test configuration involves translational constraints and where the experiments are dynamic. In order to reduce inertial moment artifacts, the mass, and moment of inertia of any loading jig structures that rotate with the specimen should be minimized. Also, the distance between these structures and the load cell should be reduced.

Synovitis biomarkers: ex vivo characterization of three biomarkers for identification of inflammatory osteoarthritis.

PubMed

Kjelgaard-Petersen, Cecilie; Siebuhr, Anne Sofie; Christiansen, Thorbjørn; Ladel, Christoph; Karsdal, Morten; Bay-Jensen, Anne-Christine

2015-01-01

Characterize biomarkers measuring extracellular matrix turnover of inflamed osteoarthritis synovium. Human primary fibroblast-like synoviocytes and synovial membrane explants (SMEs) treated with various cytokines and growth factors were assessed by C1M, C3M, and acMMP3 in the conditioned medium. TNFα significantly increased C1M up to seven-fold (p = 0.0002), C3M up to 24-fold (p = 0.0011), and acMMP3 up to 14-fold (p < 0.0001) in SMEs. IL-1β also significantly increased C1M up to five-fold (p = 0.00094), C3M four-fold (p = 0.007), and acMMP3 18-fold (p < 0.0001) in SMEs. The biomarkers C1M, C3M, and acMMP-3 were synovitis biomarkers ex vivo and provide a translational tool together with the SME model.

Galectins in the Pathogenesis of Rheumatoid Arthritis

PubMed Central

Li, Song; Yu, Yangsheng; Koehn, Christopher D; Zhang, Zhixin; Su, Kaihong

2013-01-01

Rheumatoid arthritis (RA) is a complex and common systemic autoimmune disease characterized by synovial inflammation and hyperplasia. Multiple proteins, cells, and pathways have been identified to contribute to the pathogenesis of RA. Galectins are a group of lectins that bind to β-galactoside carbohydrates on the cell surface and in the extracellular matrix. They are expressed in a wide variety of tissues and organs with the highest expression in the immune system. Galectins are potent immune regulators and modulate a range of pathological processes, such as inflammation, autoimmunity, and cancer. Accumulated evidence shows that several family members of galectins play positive or negative roles in the disease development of RA, through their effects on T and B lymphocytes, myeloid lineage cells, and fibroblast-like synoviocytes. In this review, we will summarize the function of different galectins in immune modulation and their distinct roles in RA pathogenesis. PMID:24416634

Nonlinear mechanics of non-rigid origami: an efficient computational approach

NASA Astrophysics Data System (ADS)

Liu, K.; Paulino, G. H.

2017-10-01

Origami-inspired designs possess attractive applications to science and engineering (e.g. deployable, self-assembling, adaptable systems). The special geometric arrangement of panels and creases gives rise to unique mechanical properties of origami, such as reconfigurability, making origami designs well suited for tunable structures. Although often being ignored, origami structures exhibit additional soft modes beyond rigid folding due to the flexibility of thin sheets that further influence their behaviour. Actual behaviour of origami structures usually involves significant geometric nonlinearity, which amplifies the influence of additional soft modes. To investigate the nonlinear mechanics of origami structures with deformable panels, we present a structural engineering approach for simulating the nonlinear response of non-rigid origami structures. In this paper, we propose a fully nonlinear, displacement-based implicit formulation for performing static/quasi-static analyses of non-rigid origami structures based on `bar-and-hinge' models. The formulation itself leads to an efficient and robust numerical implementation. Agreement between real models and numerical simulations demonstrates the ability of the proposed approach to capture key features of origami behaviour.

Nonlinear mechanics of non-rigid origami: an efficient computational approach.

PubMed

Liu, K; Paulino, G H

2017-10-01

Origami-inspired designs possess attractive applications to science and engineering (e.g. deployable, self-assembling, adaptable systems). The special geometric arrangement of panels and creases gives rise to unique mechanical properties of origami, such as reconfigurability, making origami designs well suited for tunable structures. Although often being ignored, origami structures exhibit additional soft modes beyond rigid folding due to the flexibility of thin sheets that further influence their behaviour. Actual behaviour of origami structures usually involves significant geometric nonlinearity, which amplifies the influence of additional soft modes. To investigate the nonlinear mechanics of origami structures with deformable panels, we present a structural engineering approach for simulating the nonlinear response of non-rigid origami structures. In this paper, we propose a fully nonlinear, displacement-based implicit formulation for performing static/quasi-static analyses of non-rigid origami structures based on 'bar-and-hinge' models. The formulation itself leads to an efficient and robust numerical implementation. Agreement between real models and numerical simulations demonstrates the ability of the proposed approach to capture key features of origami behaviour.

Static Aeroelastic Analysis with an Inviscid Cartesian Method

NASA Technical Reports Server (NTRS)

Rodriguez, David L.; Aftosmis, Michael J.; Nemec, Marian; Smith, Stephen C.

2014-01-01

An embedded-boundary Cartesian-mesh flow solver is coupled with a three degree-offreedom structural model to perform static, aeroelastic analysis of complex aircraft geometries. The approach solves the complete system of aero-structural equations using a modular, loosely-coupled strategy which allows the lower-fidelity structural model to deform the highfidelity CFD model. The approach uses an open-source, 3-D discrete-geometry engine to deform a triangulated surface geometry according to the shape predicted by the structural model under the computed aerodynamic loads. The deformation scheme is capable of modeling large deflections and is applicable to the design of modern, very-flexible transport wings. The interface is modular so that aerodynamic or structural analysis methods can be easily swapped or enhanced. This extended abstract includes a brief description of the architecture, along with some preliminary validation of underlying assumptions and early results on a generic 3D transport model. The final paper will present more concrete cases and validation of the approach. Preliminary results demonstrate convergence of the complete aero-structural system and investigate the accuracy of the approximations used in the formulation of the structural model.

Interfacial ionic 'liquids': connecting static and dynamic structures

DOE PAGES

Uysal, Ahmet; Zhou, Hua; Feng, Guang; ...

2014-12-05

It is well known that room temperature ionic liquids (RTILs) often adopt a charge-separated layered structure, i.e. with alternating cation- and anion-rich layers, at electrified interfaces. However, the dynamic response of the layered structure to temporal variations in applied potential is not well understood. For this research, we used in situ, real-time x-ray reflectivity to study the potential-dependent electric double layer (EDL) structure of an imidazolium-based RTIL on charged epitaxial graphene during potential cycling as a function of temperature. The results suggest that the graphene–RTIL interfacial structure is bistable in which the EDL structure at any intermediate potential can bemore » described by the combination of two extreme-potential structures whose proportions vary depending on the polarity and magnitude of the applied potential. This picture is supported by the EDL structures obtained by fully atomistic molecular dynamics simulations at various static potentials. Lastly, the potential-driven transition between the two structures is characterized by an increasing width but with an approximately fixed hysteresis magnitude as a function of temperature. The results are consistent with the coexistence of distinct anion- and cation-adsorbed structures separated by an energy barrier (~0.15 eV).« less

Interfacial ionic 'liquids': connecting static and dynamic structures.

PubMed

Uysal, Ahmet; Zhou, Hua; Feng, Guang; Lee, Sang Soo; Li, Song; Cummings, Peter T; Fulvio, Pasquale F; Dai, Sheng; McDonough, John K; Gogotsi, Yury; Fenter, Paul

2015-01-28

It is well known that room temperature ionic liquids (RTILs) often adopt a charge-separated layered structure, i.e. with alternating cation- and anion-rich layers, at electrified interfaces. However, the dynamic response of the layered structure to temporal variations in applied potential is not well understood. We used in situ, real-time x-ray reflectivity to study the potential-dependent electric double layer (EDL) structure of an imidazolium-based RTIL on charged epitaxial graphene during potential cycling as a function of temperature. The results suggest that the graphene-RTIL interfacial structure is bistable in which the EDL structure at any intermediate potential can be described by the combination of two extreme-potential structures whose proportions vary depending on the polarity and magnitude of the applied potential. This picture is supported by the EDL structures obtained by fully atomistic molecular dynamics simulations at various static potentials. The potential-driven transition between the two structures is characterized by an increasing width but with an approximately fixed hysteresis magnitude as a function of temperature. The results are consistent with the coexistence of distinct anion- and cation-adsorbed structures separated by an energy barrier (∼0.15 eV).

NMR evidence for static local nematicity and its cooperative interplay with low-energy magnetic fluctuations in FeSe under pressure

DOE PAGES

Wiecki, P.; Nandi, M.; Bohmer, Anna; ...

2017-11-13

Here, we present 77Se -NMR measurements on single-crystalline FeSe under pressures up to 2 GPa. Based on the observation of the splitting and broadening of the NMR spectrum due to structural twin domains, we discovered that static, local nematic ordering exists well above the bulk nematic ordering temperature, T s. The static, local nematic order and the low-energy stripe-type antiferromagnetic spin fluctuations, as revealed by NMR spin-lattice relaxation rate measurements, are both insensitive to pressure application. Our NMR results provide clear evidence for the microscopic cooperation between magnetism and local nematicity in FeSe.

NMR evidence for static local nematicity and its cooperative interplay with low-energy magnetic fluctuations in FeSe under pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiecki, P.; Nandi, M.; Bohmer, Anna

Here, we present 77Se -NMR measurements on single-crystalline FeSe under pressures up to 2 GPa. Based on the observation of the splitting and broadening of the NMR spectrum due to structural twin domains, we discovered that static, local nematic ordering exists well above the bulk nematic ordering temperature, T s. The static, local nematic order and the low-energy stripe-type antiferromagnetic spin fluctuations, as revealed by NMR spin-lattice relaxation rate measurements, are both insensitive to pressure application. Our NMR results provide clear evidence for the microscopic cooperation between magnetism and local nematicity in FeSe.

Does a Growing Static Length Scale Control the Glass Transition?

NASA Astrophysics Data System (ADS)

Wyart, Matthieu; Cates, Michael E.

2017-11-01

Several theories of the glass transition propose that the structural relaxation time τα is controlled by a growing static length scale ξ that is determined by the free energy landscape but not by the local dynamic rules governing its exploration. We argue, based on recent simulations using particle-radius-swap dynamics, that only a modest factor in the increase in τα on approach to the glass transition may stem from the growth of a static length, with a vastly larger contribution attributable, instead, to a slowdown of local dynamics. This reinforces arguments that we base on the observed strong coupling of particle diffusion and density fluctuations in real glasses.

Experimental and numerical investigation of a RC wall loaded by snow-like avalanche pressure signal

NASA Astrophysics Data System (ADS)

Ousset, Isabelle; Bertrand, David; Brun, Michaël; Limam, Ali; Naaïm, Mohamed

2013-04-01

Nowadays, civil engineering structures exposed to snow avalanches are mostly designed considering static loadings involving large safety factors. These latters highlight the lack of knowledge about the effects of the loading generated by a snow flow, and generally lead to oversize the civil structure. Indeed, the transient nature of the loading signal and also the composition of the snow flow can generate dynamic phenomena which cannot be taken into account considering only static loadings. The case of the avalanche of the Taconnaz (France), which occurred in 1999 and where important parts of the defense structure were destroyed, showed that static design approaches can lead to underestimate the potential effect of the snow flow. Thus, in order to give some new insights about this issue, the effect of the temporal variations of the snow loading on the mechanical behavior of an idealized defense structure is investigated. Therefore, a reinforced concrete (RC) wall with a L-like shape has been considered which is supposed to represent a part of the defense structure situated in Taconnaz. Static pushover tests, carried out in laboratory conditions on 1/6 scale physical model of the RC structure, allowed obtaining the capacity of the tested structure (Berthet-Rambaud et al. (2007)). Finite Element (FE) models have been developed and calibrated from the previous experimental data. The FE approach allows simulating the dynamic mechanical response of the structure. The effect of the transient nature of the loading of the avalanche has been explored applying out-of-plan dynamic loadings on the RC wall. In order to be as close as possible of a "field" snow avalanche, the imposed time evolution of the loading has been generated from in situ measurements recorded at the French experimental site "le col du Lautaret" (Thibert et al. (2008)). The RC mechanical behaviour has been described by four nonlinear constitutive laws. The four behaviour laws are compared and analyzed for specific loading situations. Next, the influences of typical parameters characterizing the avalanche loading signal are proposed. In particular, a special focused is presented on the effect of the loading rate. Finally, the vulnerability of the RC wall is studied in a reliability framework. Damage index are proposed and the probability of failure of the RC wall is derived. These relations might be useful for risk analysis.

Revealing Hidden Structural Order Controlling Both Fast and Slow Glassy Dynamics in Supercooled Liquids

NASA Astrophysics Data System (ADS)

Tong, Hua; Tanaka, Hajime

2018-01-01

The dynamics of a supercooled liquid near the glass transition is characterized by two-step relaxation, fast β and slow α relaxations. Because of the apparently disordered nature of glassy structures, there have been long debates over whether the origin of drastic slowing-down of the α relaxation accompanied by heterogeneous dynamics is thermodynamic or dynamic. Furthermore, it has been elusive whether there is any deep connection between fast β and slow α modes. To settle these issues, here we introduce a set of new structural order parameters characterizing sterically favored structures with high local packing capability, and then access structure-dynamics correlation by a novel nonlocal approach. We find that the particle mobility is under control of the static order parameter field. The fast β process is controlled by the instantaneous order parameter field locally, resulting in short-time particle-scale dynamics. Then the mobility field progressively develops with time t , following the initial order parameter field from disorder to more ordered regions. As is well known, the heterogeneity in the mobility field (dynamic heterogeneity) is maximized with a characteristic length ξ4, when t reaches the relaxation time τα. We discover that this mobility pattern can be predicted solely by a spatial coarse graining of the initial order parameter field at t =0 over a length ξ without any dynamical information. Furthermore, we find a relation ξ ˜ξ4, indicating that the static length ξ grows coherently with the dynamic one ξ4 upon cooling. This further suggests an intrinsic link between τα and ξ : the growth of the static length ξ is the origin of dynamical slowing-down. These we confirm for the first time in binary glass formers both in two and three spatial dimensions. Thus, a static structure has two intrinsic characteristic lengths, particle size and ξ , which control dynamics in local and nonlocal manners, resulting in the emergence of the two key relaxation modes, fast β and slow α processes, respectively. Because the two processes share a common structural origin, we can even predict a dynamic propensity pattern at long timescale from the fast β pattern. The presence of such intrinsic structure-dynamics correlation strongly indicates a thermodynamic nature of glass transition.

Evaluation of structural design concepts for an arrow-wing supersonic cruise aircraft

NASA Technical Reports Server (NTRS)

Sakata, I. F.; Davis, G. W.

1977-01-01

An analytical study was performed to determine the best structural approach for design of primary wing and fuselage structure of a Mach 2.7 arrow wing supersonic cruise aircraft. Concepts were evaluated considering near term start of design. Emphasis was placed on the complex interactions between thermal stress, static aeroelasticity, flutter, fatigue and fail safe design, static and dynamic loads, and the effects of variations in structural arrangements, concepts and materials on these interactions. Results indicate that a hybrid wing structure incorporating low profile convex beaded and honeycomb sandwich surface panels of titanium alloy 6Al-4V were the most efficient. The substructure includes titanium alloy spar caps reinforced with boron polyimide composites. The fuselage shell consists of hat stiffened skin and frame construction of titanium alloy 6Al-4V. A summary of the study effort is presented, and a discussion of the overall logic, design philosophy and interaction between the analytical methods for supersonic cruise aircraft design are included.

Evaluation of superplastic forming and co-diffusion bonding of Ti-6Al-4V titanium alloy expanded sandwich structures

NASA Technical Reports Server (NTRS)

Arvin, G. H.; Israeli, L.; Stolpestad, J. H.; Stacher, G. W.

1981-01-01

The application of the superplastic forming/diffusion bonding (SPF/DB) process to supersonic cruise research is investigated. The capability of an SPF/DB titanium structure to meet the structural requirements of the inner wing area of the NASA arrow-wing advanced supersonic transport design is evaluated. Selection of structural concepts and their optimization for minimum weight, SPF/DB process optimization, fabrication of representative specimens, and specimen testing and evaluation are described. The structural area used includes both upper and lower wing panels, where the upper wing panel is used for static compression strength evaluation and the lower panel, in tension, is used for fracture mechanics evaluations. The individual test specimens, cut from six large panels, consist of 39 static specimens, 10 fracture mechanics specimens, and one each full size panel for compression stability and fracture mechanics testing. Tests are performed at temperatures of -54 C (-65 F), room temperature, and 260 C (500 F).

Oriented Scintillation Spectrometer Experiment (OSSE). Revision A. Volume 1

DTIC Science & Technology

1988-05-19

SYSTEM-LEVEL ENVIRONMENTAL TESTS ................... 108 3.5.1 OPERATION REPORT, PROOF MODEL STRUCTURE TESTS.. .108 3.5.1.1 PROOF MODEL MODAL SURVEY...81 3-21 ALIGNMENT ERROR BUDGET, FOV, A4 ................ 82 3-22 ALIGNMENT ERROR BUDGET, ROTATION AXIS, A4 ...... 83 3-23 OSSE PROOF MODEL MODAL SURVEY...PROOF MODEL MODAL SURVEY .................. 112 3-27-1 OSSE PROOF MODEL STATIC LOAD TEST ............. 116 3-27-2 OSSE PROOF MODEL STATIC LOAD TEST

Reference Manual for the Ada Programming Language

DTIC Science & Technology

1983-01-01

Convercions 4-21 4.7 Qualified Expresclions 4-24 4.8 Allocators 4-24 4.9 Static Expressions and Static Subtypes 4-26 , 4.10 Universal Expressions 4-27 5...record type.•: • 2 Access types allow the construction of linked data structures created by the evaluation of / allocators . They allow several...the following: A * An assignment (In assignment statements and Initializations), an allocator , a membership test, or a short-circuit control form, * A

Numerical analysis of stiffened shells of revolution. Volume 1: Theory manual for STARS-2S, 2B, 2V digital computer programs

NASA Technical Reports Server (NTRS)

Svalbonas, V.

1973-01-01

The theoretical analysis background for the STARS-2 (shell theory automated for rotational structures) program is presented. The theory involved in the axisymmetric nonlinear and unsymmetric linear static analyses, and the stability and vibrations (including critical rotation speed) analyses involving axisymmetric prestress are discussed. The theory for nonlinear static, stability, and vibrations analyses, involving shells with unsymmetric loadings are included.

Structural DNA Nanotechnology: Artificial Nanostructures for Biomedical Research.

PubMed

Ke, Yonggang; Castro, Carlos; Choi, Jong Hyun

2018-06-04

Structural DNA nanotechnology utilizes synthetic or biologic DNA as designer molecules for the self-assembly of artificial nanostructures. The field is founded upon the specific interactions between DNA molecules, known as Watson-Crick base pairing. After decades of active pursuit, DNA has demonstrated unprecedented versatility in constructing artificial nanostructures with significant complexity and programmability. The nanostructures could be either static, with well-controlled physicochemical properties, or dynamic, with the ability to reconfigure upon external stimuli. Researchers have devoted considerable effort to exploring the usability of DNA nanostructures in biomedical research. We review the basic design methods for fabricating both static and dynamic DNA nanostructures, along with their biomedical applications in fields such as biosensing, bioimaging, and drug delivery.

Static and Dynamic Model Update of an Inflatable/Rigidizable Torus Structure

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Reaves, mercedes C.

2006-01-01

The present work addresses the development of an experimental and computational procedure for validating finite element models. A torus structure, part of an inflatable/rigidizable Hexapod, is used to demonstrate the approach. Because of fabrication, materials, and geometric uncertainties, a statistical approach combined with optimization is used to modify key model parameters. Static test results are used to update stiffness parameters and dynamic test results are used to update the mass distribution. Updated parameters are computed using gradient and non-gradient based optimization algorithms. Results show significant improvements in model predictions after parameters are updated. Lessons learned in the areas of test procedures, modeling approaches, and uncertainties quantification are presented.

Shape determination and control for large space structures

NASA Technical Reports Server (NTRS)

Weeks, C. J.

1981-01-01

An integral operator approach is used to derive solutions to static shape determination and control problems associated with large space structures. Problem assumptions include a linear self-adjoint system model, observations and control forces at discrete points, and performance criteria for the comparison of estimates or control forms. Results are illustrated by simulations in the one dimensional case with a flexible beam model, and in the multidimensional case with a finite model of a large space antenna. Modal expansions for terms in the solution algorithms are presented, using modes from the static or associated dynamic mode. These expansions provide approximated solutions in the event that a used form analytical solution to the system boundary value problem is not available.

The visual framing of graphics when used in preventative health digital news packages: exploring the use of a narrative structure as the message infrastructure.

PubMed

Sontag, Jennah M; Barnes, Spencer R

2017-09-26

Visual framing can improve health-message effectiveness. Narrative structure provides a template needed for determining how to frame visuals to maximise message effectiveness. Participants (N = 190) were assigned to a message condition determined by segments (establisher, initial, peak), graphic (static, animated) and cancer (lung, melanoma). ANOVAs revealed that melanoma was more believable than lung cancer with static graphics at the establisher and peak; narratives were more believable with animated graphics at the peak segment; melanoma elicited greater positive attitudes; graphics in the peak influenced greatest intentions. Animated graphics visually framed to emphasise information at the establisher and peak segments suggest maximum effectiveness.

Optimal design of high-speed loading spindle based on ABAQUS

NASA Astrophysics Data System (ADS)

Yang, Xudong; Dong, Yu; Ge, Qingkuan; Yang, Hai

2017-12-01

The three-dimensional model of high-speed loading spindle is established by using ABAQUS’s modeling module. A finite element analysis model of high-speed loading spindle was established by using spring element to simulate bearing boundary condition. The static and dynamic performance of the spindle structure with different specifications of the rectangular spline and the different diameter neck of axle are studied in depth, and the influence of different spindle span on the static and dynamic performance of the high-speed loading spindle is studied. Finally, the optimal structure of the high-speed loading spindle is obtained. The results provide a theoretical basis for improving the overall performance of the test-bed

Necessity of Grammar Teaching

ERIC Educational Resources Information Center

Zhang, Jianyun

2009-01-01

Grammar is often misunderstood in the language teaching field. The misconception lies in the view that grammar is a collection of arbitrary rules about static structures in the language. Further questionable claims are that the structures do not have to be thought, learners will acquire them on their own, or if the structures are taught, the…

ATM/cable arch and beam structural test program

NASA Technical Reports Server (NTRS)

Housley, J. A.

1972-01-01

The structural testing is described of an Apollo Telescope Mount (ATM) cable arch and beam assembly, using static loads to simulate the critical conditions expected during transportation and launch of the ATM. All test objectives were met. Stress and deflection data show that the assembly is structurally adequate for use in the ATM.

Intra-articular Enzyme Replacement Therapy with rhIDUA is Safe, Well-Tolerated, and Reduces Articular GAG Storage in the Canine Model of Mucopolysaccharidosis Type I

PubMed Central

Wang, Raymond Y; Aminian, Afshin; McEntee, Michael F; Kan, Shih-Hsin; Simonaro, Calogera M; Lamanna, William; Lawrence, Roger; Ellinwood, N. Matthew; Guerra, Catalina; Le, Steven Q; Dickson, Patricia I; Esko, Jeffrey D

2014-01-01

Background Treatment with intravenous enzyme replacement therapy and hematopoietic stem cell transplantation for mucopolysaccharidosis (MPS) type I does not address joint disease, resulting in persistent orthopedic complications and impaired quality of life. A proof-of-concept study was conducted to determine the safety, tolerability, and efficacy of intra-articular recombinant human iduronidase (IA-rhIDUA) enzyme replacement therapy in the canine MPS I model. Methods Four MPS I dogs underwent monthly rhIDUA injections (0.58 mg/joint) into the right elbow and knee for six months. Contralateral elbows and knees concurrently received normal saline. No intravenous rhIDUA therapy was administered. Monthly blood counts, chemistries, anti-rhIDUA antibody titers, and synovial fluid cell counts were measured. Lysosomal storage of synoviocytes and chondrocytes, synovial macrophages and plasma cells were scored at baseline and one month following the final injection. Results All injections were well-tolerated without adverse reactions. One animal required prednisone for spinal cord compression. There were no clinically significant abnormalities in blood counts or chemistries. Circulating anti-rhIDUA antibody titers gradually increased in all dogs except the prednisone-treated dog; plasma cells, which were absent in all baseline synovial specimens, were predominantly found in synovium of rhIDUA-treated joints at study-end. Lysosomal storage in synoviocytes and chondrocytes following 6 months of IA-rhIDUA demonstrated significant reduction compared to tissues at baseline, and saline-treated tissues at study-end. Mean joint synovial GAG levels in IA-rhIDUA joints was 8.62±5.86 μg/mg dry weight and 21.6±10.4 μg/mg dry weight in control joints (60% reduction). Cartilage heparan sulfate was also reduced in the IA-rhIDUA joints (113±39.5 ng/g wet weight) compared to saline-treated joints (142±56.4 ng/g wet weight). Synovial macrophage infiltration, which was present in all joints at baseline, was abolished in rhIDUA-treated joints only. Conclusions Intra-articular rhIDUA is well-tolerated and safe in the canine MPS I animal model. Qualitative and quantitative assessments indicate that IA-rhIDUA successfully reduces tissue and cellular GAG storage in synovium and articular cartilage, including cartilage deep to the articular surface, and eliminates inflammatory macrophages from synovial tissue. PMID:24951454

Development of the Main Wing Structure of a High Altitude Long Endurance UAV

NASA Astrophysics Data System (ADS)

Park, Sang Wook; Shin, Jeong Woo; Kim, Tae-Uk

2018-04-01

To enhance the flight endurance of a HALE UAV, the main wing of the UAV should have a high aspect ratio and low structural weight. Since a main wing constructed with the thin walled and slender components needed for low structural weight can suffer catastrophic failure during flight, it is important to develop a light-weight airframe without sacrificing structural integrity. In this paper, the design of the main wing of the HALE UAV was conducted using spars which were composed of a carbon-epoxy cylindrical tube and bulkheads to achieve both the weight reduction and structural integrity. The spars were sized using numerical analysis considering non-linear deformation under bending moment. Static strength testing of the wing was conducted under the most critical load condition. Then, the experimental results obtained for the wing were compared to the analytical result from the non-linear finite-element analysis. It was found that the developed main wing reduced its structural weight without any failure under the ultimate load condition of the static strength testing.

Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures

NASA Technical Reports Server (NTRS)

Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

2013-01-01

Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading. Keywords: fiber optic, distributed strain sensing, Rayleigh scatter, optical frequency domain reflectometry

Symptom and structure modification in osteoarthritis with pharmaceutical-grade chondroitin sulfate: what's the evidence?

PubMed

Hochberg, M; Chevalier, X; Henrotin, Y; Hunter, D J; Uebelhart, D

2013-03-01

Osteoarthritis is a chronic disease characterized by irreversible damage to joint structures, including loss of articular cartilage, osteophyte formation, alterations in the subchondral bone and synovial inflammation. It has been shown that chondroitin sulfate interferes with the progression of structural changes in joint tissues and is used in the management of patients with osteoarthritis. This review summarizes data from relevant reports describing the mechanisms of action of chondroitin sulfate that may explain the beneficial effects of the drug and examines the evidence for clinical efficacy of oral chondroitin sulfate in osteoarthritis. Data included in the review were derived from a literature search in PubMed. Literature searches were performed in PubMed using the search terms 'chondroitin sulfate', 'pharmaceutical-grade', 'osteoarthritis', 'randomized clinical trials', 'humans'. The MEDLINE database was searched from January 1996 through August 2012 for all randomized controlled trials, meta-analyses, systematic reviews, and review articles of chondroitin sulfate in osteoarthritis. Chondroitin sulfate exerts in vitro a beneficial effect on the metabolism of different cell lines: chondrocytes, synoviocytes and cells from subchondral bone, all involved in osteoarthritis. It increases type II collagen and proteoglycan synthesis in human articular chondrocytes and is able to reduce the production of some pro-inflammatory factors and proteases, to reduce the cellular death process, and improve the anabolic/catabolic balance of the extracellular cartilage matrix (ECM). Clinical trials have reported a beneficial effect of chondroitin sulfate on pain and function. The structure-modifying effects of chondroitin sulfate have been reported and analyzed in recent meta-analyses. The results in knee osteoarthritis demonstrate a small but significant reduction in the rate of decline in joint space width. Because chondroitin sulfate quality of several nutraceuticals has been found to be poor, it is recommended that pharmaceutical-grade chondroitin sulfate is used rather than food supplements in the treatment of OA. Chondroitin sulfate is recommended by several guidelines from international societies in the management of knee and hip OA. Furthermore, its safety profile is favorable when compared with many other therapies used in OA. Chondroitin sulfate is an effective and safe treatment option for patients with osteoarthritis.

The behavior of Aluminium Carbon/Epoxy fibre metal laminate under quasi-static loading

NASA Astrophysics Data System (ADS)

Romli, N. K.; Rejab, M. R. M.; Bachtiar, D.; Siregar, J.; Rani, M. F.; Harun, W. S. W.; Salleh, Salwani Mohd; Merzuki, M. N. M.

2017-10-01

One of major concerns that related to the flight safety is impact of birds. To minimize the risks, there is need to increase the impact resistance of aircraft by developing a new material and has the good structural design of aircraft structures. The hybrid laminates are potential candidate material to be applied for the aircraft structures susceptible to bird strikes. The fibre metal laminate was fabricated by a compression moulding technique. The carbon fibre and aluminium alloy 2024-0 was laminated by using thermoset epoxy. A compression moulding technique was used for the FML fabrication. The aluminium sheet metal has been roughening by a metal sanding method which to improve the bonding between the fibre and metal layer. The main objective of this paper is to determine the failure response of the laminate under five variations of the crosshead displacement in the quasi-static loading. The FML was modelled and analysed by using Explicit solver. Based on the experimental data of the quasi-static test, the result of 1 mm/min was 11.85 kN and higher than 5, 10, 50 and 100 mm/min which because of the aluminium ductility during the impact loading response. The numerical simulations were generally in good agreement with the experimental measurements.

Development of an Atlas of Strengths and Establishment of an Appropriate Model Structure

DTIC Science & Technology

1981-11-01

exercise hyperaemic response was greater for a given duration of contraction in water at 34 and 42*C than at lower temperatures. The rate of blood flow...Lambie, D.G. and Johnson, R.H. Ventilatory responses to sustained static forearm exercise in man. New Zealand Med. Journal; 1978, 88(618), 169...KEYWORDS: Static exercise , ventilatory responses . METHODS: Five healthy subjects were used to study the stimulus for hyperventilation which occurs during

Review of Aircraft Crash Structural Response Research.

DTIC Science & Technology

1982-08-01

structures consisting of conventional built-up metallic construction and those consisting of advanced composite materials were of interest. The latter...increasing importance. Some recent theoretical and experimental studies of the behavior of composite - material structures subjected to severe static...dynamic, and/or impact conditions are noted. Such topics as crashworthiness testing ot composite fuselage structures, the impact resistance of graphite and

Study on embedding fiber Bragg grating sensor into the 3D printing structure for health monitoring

NASA Astrophysics Data System (ADS)

Li, Ruiya; Tan, Yuegang; Zhou, Zude; Fang, Liang; Chen, Yiyang

2016-10-01

3D printing technology is a rapidly developing manufacturing technology, which is known as a core technology in the third industrial revolution. With the continuous improvement of the application of 3D printing products, the health monitoring of the 3D printing structure is particularly important. Fiber Bragg grating (FBG) sensing technology is a new type of optical sensing technology with unique advantages comparing to traditional sensing technology, and it has great application prospects in structural health monitoring. In this paper, the FBG sensors embedded in the internal structure of the 3D printing were used to monitor the static and dynamic strain variation of 3D printing structure during loading process. The theoretical result and experimental result has good consistency and the characteristic frequency detected by FBG sensor is consistent with the testing results of traditional accelerator in the dynamic experiment. The results of this paper preliminary validate that FBG embedded in the 3D printing structure can effectively detecting the static and dynamic stain change of the 3D printing structure, which provide some guidance for the health monitoring of 3D printing structure.

Structure of Room Temperature Ionic Liquids on Charged Graphene: An integrated experimental and computational study

NASA Astrophysics Data System (ADS)

Uysal, Ahmet; Zhou, Hua; Lee, Sang Soo; Fenter, Paul; Feng, Guang; Li, Song; Cummings, Peter; Fulvio, Pasquale; Dai, Sheng; McDonough, Jake; Gogotsi, Yury

2014-03-01

Electrical double layer capacitors (EDLCs) with room temperature ionic liquid (RTIL) electrolytes and carbon electrodes are promising candidates for energy storage devices with high power density and long cycle life. We studied the potential and time dependent changes in the electric double layer (EDL) structure of an imidazolium-based room temperature ionic liquid (RTIL) electrolyte at an epitaxial graphene (EG) surface. We used in situ x-ray reflectivity (XR) to determine the EDL structure at static potentials, during cyclic voltammetry (CV) and potential step measurements. The static potential structures were also investigated with fully atomistic molecular dynamics (MD) simulations. Combined XR and MD results show that the EDL structure has alternating anion/cation layers within the first nanometer of the interface. The dynamical response of the EDL to potential steps has a slow component (>10 s) and the RTIL structure shows hysteresis during CV scans. We propose a conceptual model that connects nanoscale interfacial structure to the macroscopic measurements. This material is based upon work supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science (SC), Office of Basic Energy

Expelled grains from an unseen parent body around AU Microscopii

NASA Astrophysics Data System (ADS)

Sezestre, É.; Augereau, J.-C.; Boccaletti, A.; Thébault, P.

2017-11-01

Context. Recent observations of the edge-on debris disk of AU Mic have revealed asymmetric, fast outward-moving arch-like structures above the disk midplane. Although asymmetries are frequent in debris disks, no model can readily explain the characteristics of these features. Aims: We present a model aiming to reproduce the dynamics of these structures, more specifically their high projected speeds and their apparent position. We test the hypothesis of dust emitted by a point source and then expelled from the system by the strong stellar wind of this young M-type star. In this model we make the assumption that the dust grains follow the same dynamics as the structures, I.e., they are not local density enhancements. Methods: We perform numerical simulations of test particle trajectories to explore the available parameter space, in particular the radial location R0 of the dust producing parent body and the size of the dust grains as parameterized by the value of β (ratio of stellar wind and radiation pressure forces over gravitation). We consider the cases of a static and of an orbiting parent body. Results: We find that for all considered scenarios (static or moving parent body), there is always a set of (R0,β) parameters able to fit the observed features. The common characteristics of these solutions is that they all require a high value of β, of around 6. This means that the star is probably very active, and the grains composing the structures are submicronic in order for observable grains to reach such high β values. We find that the location of the hypothetical parent body is closer in than the planetesimal belt, around 8 ± 2 au (orbiting case) or 28 ± 7 au (static case). A nearly periodic process of dust emission appears, of 2 yr in the orbiting scenarios and 7 yr in the static case. Conclusions: We show that the scenario of sequential dust releases by an unseen point-source parent body is able to explain the radial behavior of the observed structures. We predict the evolution of the structures to help future observations discriminate between the different parent body configurations that have been considered. In the orbiting parent body scenario, we expect new structures to appear on the northwest side of the disk in the coming years.

Redundant Asynchronous Microprocessor System

NASA Technical Reports Server (NTRS)

Meyer, G.; Johnston, J. O.; Dunn, W. R.

1985-01-01

Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

Radiative-Transfer Modeling of Spectra of Densely Packed Particulate Media

NASA Astrophysics Data System (ADS)

Ito, G.; Mishchenko, M. I.; Glotch, T. D.

2017-12-01

Remote sensing measurements over a wide range of wavelengths from both ground- and space-based platforms have provided a wealth of data regarding the surfaces and atmospheres of various solar system bodies. With proper interpretations, important properties, such as composition and particle size, can be inferred. However, proper interpretation of such datasets can often be difficult, especially for densely packed particulate media with particle sizes on the order of wavelength of light being used for remote sensing. Radiative transfer theory has often been applied to the study of densely packed particulate media like planetary regoliths and snow, but with difficulty, and here we continue to investigate radiative transfer modeling of spectra of densely packed media. We use the superposition T-matrix method to compute scattering properties of clusters of particles and capture the near-field effects important for dense packing. Then, the scattering parameters from the T-matrix computations are modified with the static structure factor correction, accounting for the dense packing of the clusters themselves. Using these corrected scattering parameters, reflectance (or emissivity via Kirchhoff's Law) is computed with the method of invariance imbedding solution to the radiative transfer equation. For this work we modeled the emissivity spectrum of the 3.3 µm particle size fraction of enstatite, representing some common mineralogical and particle size components of regoliths, in the mid-infrared wavelengths (5 - 50 µm). The modeled spectrum from the T-matrix method with static structure factor correction using moderate packing densities (filling factors of 0.1 - 0.2) produced better fits to the laboratory measurement of corresponding spectrum than the spectrum modeled by the equivalent method without static structure factor correction. Future work will test the method of the superposition T-matrix and static structure factor correction combination for larger particles sizes and polydispersed clusters in search for the most effective modeling of spectra of densely packed particulate media.

Epidemics Modelings: Some New Challenges

NASA Astrophysics Data System (ADS)

Boatto, Stefanella; Khouri, Renata Stella; Solerman, Lucas; Codeço, Claudia; Bonnet, Catherine

2010-09-01

Epidemics modeling has been particularly growing in the past years. In epidemics studies, mathematical modeling is used in particular to reach a better understanding of some neglected diseases (dengue, malaria, …) and of new emerging ones (SARS, influenza A,….) of big agglomerates. Such studies offer new challenges both from the modeling point of view (searching for simple models which capture the main characteristics of the disease spreading), data analysis and mathematical complexity. We are facing often with complex networks especially when modeling the city dynamics. Such networks can be static (in first approximation) and homogeneous, static and not homogeneous and/or not static (when taking into account the city structure, micro-climates, people circulation, etc.). The objective being studying epidemics dynamics and being able to predict its spreading.

Piezoelectric control of columns prone to instabilities and nonlinear modal interaction

NASA Astrophysics Data System (ADS)

Sridharan, Srinivasan; Kim, Sunjung

2008-06-01

This paper attempts to unravel the issues of piezoelectric control of structures prone to nonlinear static and dynamic instabilities. A simple yet typical example is considered, namely the problem of a simply supported axially compressed imperfect column on an elastic softening foundation. Here the significant nonlinearity arises from the softening foundation. The column is so designed as to have coincident critical loads for the first two modes of buckling. Piezoelectric actuators/sensors are deemed to be attached to a column in regions of maximum strain at several locations along the length of the column. The issues involved in (i) enhancing the static buckling load, (ii) suppression of vibrations as the column is compressed to a load close to its dynamic instability load and (iii) enhancing the dynamic instability load are investigated and discussed. It is shown that there is a premium price to pay for enhancing the buckling capacity of the column, be it static or dynamic. The paper concludes by alluding to the possibility of a failure of patch control if a higher-order shortwave mode happens to be the governing principal mode of the structure.

A Multiscale Model for the Quasi-Static Thermo-Plastic Behavior of Highly Cross-Linked Glassy Polymers

DOE PAGES

Vu-Bac, N.; Bessa, M. A.; Rabczuk, Timon; ...

2015-09-10

In this paper, we present experimentally validated molecular dynamics predictions of the quasi- static yield and post-yield behavior for a highly cross-linked epoxy polymer under gen- eral stress states and for different temperatures. In addition, a hierarchical multiscale model is presented where the nano-scale simulations obtained from molecular dynamics were homogenized to a continuum thermoplastic constitutive model for the epoxy that can be used to describe the macroscopic behavior of the material. Three major conclusions were achieved: (1) the yield surfaces generated from the nano-scale model for different temperatures agree well with the paraboloid yield crite- rion, supporting previous macroscopicmore » experimental observations; (2) rescaling of the entire yield surfaces to the quasi-static case is possible by considering Argon’s theoretical predictions for pure compression of the polymer at absolute zero temperature; (3) nano- scale simulations can be used for an experimentally-free calibration of macroscopic con- tinuum models, opening new avenues for the design of materials and structures through multi-scale simulations that provide structure-property-performance relationships.« less

In Vitro Mimetic Models for the Bone-Cartilage Interface Regeneration.

PubMed

Bicho, Diana; Pina, Sandra; Oliveira, J Miguel; Reis, Rui L

2018-01-01

In embryonic development, pure cartilage structures are in the basis of bone-cartilage interfaces. Despite this fact, the mature bone and cartilage structures can vary greatly in composition and function. Nevertheless, they collaborate in the osteochondral region to create a smooth transition zone that supports the movements and forces resulting from the daily activities. In this sense, all the hierarchical organization is involved in the maintenance and reestablishment of the equilibrium in case of damage. Therefore, this interface has attracted a great deal of interest in order to understand the mechanisms of regeneration or disease progression in osteoarthritis. With that purpose, in vitro tissue models (either static or dynamic) have been studied. Static in vitro tissue models include monocultures, co-cultures, 3D cultures, and ex vivo cultures, mostly cultivated in flat surfaces, while dynamic models involve the use of bioreactors and microfluidic systems. The latter have emerged as alternatives to study the cellular interactions in a more authentic manner over some disadvantages of the static models. The current alternatives of in vitro mimetic models for bone-cartilage interface regeneration are overviewed and discussed herein.

Characteristics on electodynamic suspension simulator with HTS levitation magnet

NASA Astrophysics Data System (ADS)

Lee, J.; Bae, D. K.; Sim, K.; Chung, Y. D.; Lee, Y.-S.

2009-10-01

High- Tc superconducting (HTSC) electrodynamic suspension (EDS) system basically consists of the HTSC levitation magnet and the ground conductor. The levitation force of EDS system is forms by the interaction between the moving magnetic field produced by the onboard levitation magnet and the induced magnetic field produced by eddy current in the ground conductor. This paper deals with the characteristics of the EDS simulators with high- Tc superconducting (HTS) levitation magnet. Two EDS simulator systems, rotating type EDS simulator and static type EDS simulator, were studied in this paper. The rotating type EDS simulator consists of a HTS levitation magnet and a 1.5 m diameter rotating ground conductor, a motor, the supporting structure and force measuring devices. In the static type EDS simulator, instead of moving magnetic field, AC current was applied to the fixed HTS levitation magnet to induce the eddy current. The static type EDS simulator consists of a HTS levitation magnet, a ground conductor, force measuring devices and supporting structure. The double-pancake type HTSC levitation magnet was designed, manufactured and tested in the EDS simulator.

Structural relaxation in a binary metallic melt: Molecular dynamics computer simulation of undercooled Al80Ni20

NASA Astrophysics Data System (ADS)

Das, Subir K.; Horbach, Jürgen; Voigtmann, Thomas

2008-08-01

Molecular dynamics computer simulations are performed to study structure and structural relaxation in the glassforming metallic alloy Al80Ni20 . The interactions between the particles are modeled by an effective potential of the embedded atom type. Our model of Al80Ni20 exhibits chemical short-range order (CSRO) that is reflected in a broad prepeak around a wave number of 1.8Å-1 in the partial static structure factor for the Ni-Ni correlations. The CSRO is due to the preference of Ni atoms to have Al rather than Ni atoms as nearest neighbors. By analyzing incoherent and coherent intermediate scattering functions as well as self-diffusion constants and shear viscosity, we discuss how the chemical ordering is reflected in the dynamics of the deeply undercooled melt. The q dependence of the α relaxation time as well as the Debye-Waller factor for the Al-Al correlations show oscillations at the location of the prepeak in the partial static structure factor for the Ni-Ni correlations. The latter feature of the Debye-Waller factor is well reproduced by a calculation in the framework of the mode coupling theory (MCT) of the glass transition, using the partial static structure factors from the simulation as input. We also check the validity of the Stokes-Einstein-Sutherland formula that relates the self-diffusion coefficients with the shear viscosity. We show that it breaks down already far above the mode coupling critical temperature Tc . The failure of the Stokes-Einstein-Sutherland relation is not related to the specific chemical ordering in Al80Ni20 .

Exploring the structure and function of temporal networks with dynamic graphlets

PubMed Central

Hulovatyy, Y.; Chen, H.; Milenković, T.

2015-01-01

Motivation: With increasing availability of temporal real-world networks, how to efficiently study these data? One can model a temporal network as a single aggregate static network, or as a series of time-specific snapshots, each being an aggregate static network over the corresponding time window. Then, one can use established methods for static analysis on the resulting aggregate network(s), but losing in the process valuable temporal information either completely, or at the interface between different snapshots, respectively. Here, we develop a novel approach for studying a temporal network more explicitly, by capturing inter-snapshot relationships. Results: We base our methodology on well-established graphlets (subgraphs), which have been proven in numerous contexts in static network research. We develop new theory to allow for graphlet-based analyses of temporal networks. Our new notion of dynamic graphlets is different from existing dynamic network approaches that are based on temporal motifs (statistically significant subgraphs). The latter have limitations: their results depend on the choice of a null network model that is required to evaluate the significance of a subgraph, and choosing a good null model is non-trivial. Our dynamic graphlets overcome the limitations of the temporal motifs. Also, when we aim to characterize the structure and function of an entire temporal network or of individual nodes, our dynamic graphlets outperform the static graphlets. Clearly, accounting for temporal information helps. We apply dynamic graphlets to temporal age-specific molecular network data to deepen our limited knowledge about human aging. Availability and implementation: http://www.nd.edu/∼cone/DG. Contact: tmilenko@nd.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26072480

Influences of posterior-located center of gravity on lumbar extension strength, balance, and lumbar lordosis in chronic low back pain.

PubMed

Kim, Dae-Hun; Park, Jin-Kyu; Jeong, Myeong-Kyun

2014-01-01

In patients with chronic low back pain, the center of gravity (COG) is abnormally located posterior to the center in most cases. The purpose of this study was to examine the effects of posterior-located COG on the functions (lumbar extension strength, and static and dynamic balance) and structure (lumbar lordosis angle and lumbosacral angle) of the lumbar spine. In this study, the COG of chronic low back pain patients who complained of only low back pain were examined using dynamic body balance equipment. A total of 164 subjects participated in the study (74 males and 90 females), and they were divided into two groups of 82 patients each. One group (n=82) consisted of patients whose COG was located at the center (C-COG); the other group (n=82) consisted of patients whose COG was located posterior to the center (P-COG). The following measures assessed the lumber functions and structures of the two groups: lumbar extension strength, moving speed of static and dynamic COGs, movement distance of the static and dynamic COGs, lumbar lordosis angle, and lumbosacral angle. The measured values were analyzed using independent t-tests. The group of patients with P-COG showed more decreases in lumbar extension strength, lumbar lordosis angle, and lumbosacral angle compared to the group of patients with C-COG. Also this group showed increases in moving speed and movement distance of the static COG. However, there were no differences in moving speed and movement distance of the dynamic COG between the two groups. These findings suggest that chronic LBP patients with P-COG have some disadvantages to establish lumbar extension strength and static and dynamic balance, which require specific efforts to maintain a neutral position and to control posture.

A 3D inversion for all-space magnetotelluric data with static shift correction

NASA Astrophysics Data System (ADS)

Zhang, Kun

2017-04-01

Base on the previous studies on the static shift correction and 3D inversion algorithms, we improve the NLCG 3D inversion method and propose a new static shift correction method which work in the inversion. The static shift correction method is based on the 3D theory and real data. The static shift can be detected by the quantitative analysis of apparent parameters (apparent resistivity and impedance phase) of MT in high frequency range, and completed correction with inversion. The method is an automatic processing technology of computer with 0 cost, and avoids the additional field work and indoor processing with good results. The 3D inversion algorithm is improved (Zhang et al., 2013) base on the NLCG method of Newman & Alumbaugh (2000) and Rodi & Mackie (2001). For the algorithm, we added the parallel structure, improved the computational efficiency, reduced the memory of computer and added the topographic and marine factors. So the 3D inversion could work in general PC with high efficiency and accuracy. And all the MT data of surface stations, seabed stations and underground stations can be used in the inversion algorithm.

Numerical Modeling of Sliding Stability of RCC dam

NASA Astrophysics Data System (ADS)

Mughieda, O.; Hazirbaba, K.; Bani-Hani, K.; Daoud, W.

2017-06-01

Stability and stress analyses are the most important elements that require rigorous consideration in design of a dam structure. Stability of dams against sliding is crucial due to the substantial horizontal load that requires sufficient and safe resistance to develop by mobilization of adequate shearing forces along the base of the dam foundation. In the current research, the static sliding stability of a roller-compacted-concrete (RCC) dam was modelled using finite element method to investigate the stability against sliding. A commercially available finite element software (SAP 2000) was used to analyze stresses in the body of the dam and foundation. A linear finite element static analysis was performed in which a linear plane strain isoperimetric four node elements was used for modelling the dam-foundation system. The analysis was carried out assuming that no slip will occur at the interface between the dam and the foundation. Usual static loading condition was applied for the static analysis. The greatest tension was found to develop in the rock adjacent to the toe of the upstream slope. The factor of safety against sliding along the entire base of the dam was found to be greater than 1 (FS>1), for static loading conditions.

Student Leadership in Small Group Science Inquiry

ERIC Educational Resources Information Center

Oliveira, Alandeom W.; Boz, Umit; Broadwell, George A.; Sadler, Troy D.

2014-01-01

Background: Science educators have sought to structure collaborative inquiry learning through the assignment of static group roles. This structural approach to student grouping oversimplifies the complexities of peer collaboration and overlooks the highly dynamic nature of group activity. Purpose: This study addresses this issue of…

16 CFR 1207.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... means members providing structural support to the assembled, installed slide. (5) Casual contact means...) Performance test means a test to measure the functional or structural characteristics of the slide and may... measurements of the slide's response to dynamic and static loads. (20) [Reserved] (21) Pinching hazard means...

Dynamic tests of composite panels of an aircraft wing

NASA Astrophysics Data System (ADS)

Splichal, Jan; Pistek, Antonin; Hlinka, Jiri

2015-10-01

The paper describes the analysis of aerospace composite structures under dynamic loading. Today, it is common to use design procedures based on assumption of static loading only, and dynamic loading is rarely assumed and applied in design and certification of aerospace structures. The paper describes the application of dynamic loading for the design of aircraft structures, and the validation of the procedure on a selected structure. The goal is to verify the possibility of reducing the weight through improved design/modelling processes using dynamic loading instead of static loading. The research activity focuses on the modelling and testing of a composite panel representing a local segment of an aircraft wing section, investigating in particular the buckling behavior under dynamic loading. Finite Elements simulation tools are discussed, as well as the advantages of using a digital optical measurement system for the evaluation of the tests. The comparison of the finite element simulations with the results of the tests is presented.

A nonlinear vibration isolator achieving high-static-low-dynamic stiffness and tunable anti-resonance frequency band

NASA Astrophysics Data System (ADS)

Sun, Xiuting; Jing, Xingjian

2016-12-01

This study investigates theoretically and experimentally a vibration isolator constructed by an n-layer Scissor-Like Structure (SLS), focusing on the analysis and design of nonlinear stiffness and damping characteristics for advantageous isolation performance in both orthogonal directions. With the mathematical modeling, the influence incurred by different structural parameters on system isolation performance is studied. It is shown that, (a) nonlinear high-static-low-dynamic stiffness and damping characteristics can be seen such that the system can achieve good isolation performance in both directions, (b) an anti-resonance frequency band exists due to the coupling effect between the linear and nonlinear stiffness in the two orthogonal directions within the structure, and (c) all these performances are designable with several structural parameters. The advantages of the proposed system are shown through comparisons with an existing quasi-zero-stiffness vibration isolator (QZS-VI) and a traditional mass-spring-damper vibration isolator (MSD-VI), and further validated by experimental results.

High Temperature Composite Analyzer (HITCAN) demonstration manual, version 1.0

NASA Technical Reports Server (NTRS)

Singhal, S. N; Lackney, J. J.; Murthy, P. L. N.

1993-01-01

This manual comprises a variety of demonstration cases for the HITCAN (HIgh Temperature Composite ANalyzer) code. HITCAN is a general purpose computer program for predicting nonlinear global structural and local stress-strain response of arbitrarily oriented, multilayered high temperature metal matrix composite structures. HITCAN is written in FORTRAN 77 computer language and has been configured and executed on the NASA Lewis Research Center CRAY XMP and YMP computers. Detailed description of all program variables and terms used in this manual may be found in the User's Manual. The demonstration includes various cases to illustrate the features and analysis capabilities of the HITCAN computer code. These cases include: (1) static analysis, (2) nonlinear quasi-static (incremental) analysis, (3) modal analysis, (4) buckling analysis, (5) fiber degradation effects, (6) fabrication-induced stresses for a variety of structures; namely, beam, plate, ring, shell, and built-up structures. A brief discussion of each demonstration case with the associated input data file is provided. Sample results taken from the actual computer output are also included.

Magnetic structure and excitation spectrum of the hyperhoneycomb Kitaev magnet β -Li2IrO3

NASA Astrophysics Data System (ADS)

Ducatman, Samuel; Rousochatzakis, Ioannis; Perkins, Natalia B.

2018-03-01

We present a theoretical study of the static and dynamical properties of the three-dimensional, hyperhoneycomb Kitaev magnet β -Li2IrO3 . We argue that the observed incommensurate order can be understood in terms of a long-wavelength twisting of a nearby commensurate period-3 state, with the same key qualitatively features. The period-3 state shows very different structure when either the Kitaev interaction K or the off-diagonal exchange anisotropy Γ is dominant. A comparison of the associated static spin structure factors with reported scattering experiments in zero and finite fields gives strong evidence that β -Li2IrO3 lies in the regime of dominant Kitaev coupling, and that the Heisenberg exchange J is much weaker than both K and Γ . Our predictions for the magnon excitation spectra, the dynamical spin structure factors, and their polarization dependence provide additional distinctive fingerprints that can be checked experimentally.

A first step towards a consensus static in vitro model for simulating full-term infant digestion.

PubMed

Ménard, O; Bourlieu, C; De Oliveira, S C; Dellarosa, N; Laghi, L; Carrière, F; Capozzi, F; Dupont, D; Deglaire, A

2018-02-01

In vitro alternatives to clinical trials are used for studying human food digestion. For simulating infant digestion, only a few models, lacking physiological relevance, are available. Thanks to an extensive literature review of the in vivo infant digestive conditions, a gastrointestinal static in vitro model was developed for infants born at term and aged 28days. The model was applied to the digestion of a commercial infant formula. Kinetics of digestion, as well as the structural evolution, were compared with those obtained while submitting the same formula to the adult international consensus protocol of in vitro static digestion. The kinetics of proteolysis and lipolysis differed according to the physiological stage resulting mainly from the reduced level of enzymes and bile salts, as well as the higher gastric pH in the infant model. This in vitro static model of infant digestion is of interest for scientists, food or pharmaceutical manufacturers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Terapascal static pressure generation with ultrahigh yield strength nanodiamond.

PubMed

Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

2016-07-01

Studies of materials' properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications.

Terapascal static pressure generation with ultrahigh yield strength nanodiamond

PubMed Central

Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A.; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B.; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

2016-01-01

Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications. PMID:27453944

Static and Dynamic Facial Cues Differentially Affect the Consistency of Social Evaluations.

PubMed

Hehman, Eric; Flake, Jessica K; Freeman, Jonathan B

2015-08-01

Individuals are quite sensitive to others' appearance cues when forming social evaluations. Cues such as facial emotional resemblance are based on facial musculature and thus dynamic. Cues such as a face's structure are based on the underlying bone and are thus relatively static. The current research examines the distinction between these types of facial cues by investigating the consistency in social evaluations arising from dynamic versus static cues. Specifically, across four studies using real faces, digitally generated faces, and downstream behavioral decisions, we demonstrate that social evaluations based on dynamic cues, such as intentions, have greater variability across multiple presentations of the same identity than do social evaluations based on static cues, such as ability. Thus, although evaluations of intentions vary considerably across different instances of a target's face, evaluations of ability are relatively fixed. The findings highlight the role of facial cues' consistency in the stability of social evaluations. © 2015 by the Society for Personality and Social Psychology, Inc.

Stylized facts in social networks: Community-based static modeling

NASA Astrophysics Data System (ADS)

Jo, Hang-Hyun; Murase, Yohsuke; Török, János; Kertész, János; Kaski, Kimmo

2018-06-01

The past analyses of datasets of social networks have enabled us to make empirical findings of a number of aspects of human society, which are commonly featured as stylized facts of social networks, such as broad distributions of network quantities, existence of communities, assortative mixing, and intensity-topology correlations. Since the understanding of the structure of these complex social networks is far from complete, for deeper insight into human society more comprehensive datasets and modeling of the stylized facts are needed. Although the existing dynamical and static models can generate some stylized facts, here we take an alternative approach by devising a community-based static model with heterogeneous community sizes and larger communities having smaller link density and weight. With these few assumptions we are able to generate realistic social networks that show most stylized facts for a wide range of parameters, as demonstrated numerically and analytically. Since our community-based static model is simple to implement and easily scalable, it can be used as a reference system, benchmark, or testbed for further applications.

Characteristics of middle and upper tropospheric clouds as deduced from rawinsonde data

NASA Technical Reports Server (NTRS)

Starr, D. D. O.; Cox, S. K.

1982-01-01

The static environment of middle and upper tropospheric clouds is characterized. Computed relative humidity with respect to ice is used to diagnose the presence of cloud layer. The deduced seasonal mean cloud cover estimates based on this technique are shown to be reasonable. The cases are stratified by season and pressure thickness, and the dry static stability, vertical wind speed shear, and Richardson number are computed for three layers for each case. Mean values for each parameter are presented for each stratification and layer. The relative frequency of occurrence of various structures is presented for each stratification. The observed values of each parameter and the observed structure of each parameter are quite variable. Structures corresponding to any of a number of different conceptual models may be found. Moist adiabatic conditions are not commonly observed and the stratification based on thickness yields substantially different results for each group.

Design of a compact static Fourier transform spectrometer in integrated optics based on a leaky loop structure.

PubMed

Martin, Bruno; Morand, Alain; Benech, Pierre; Leblond, Gregory; Blaize, Sylvain; Lerondel, Gilles; Royer, Pascal; Kern, Pierre; Le Coarer, Etienne

2009-01-15

A compact static Fourier transform spectrometer for integrated optics is proposed. It is based on a plane leaky loop structure combined with a plane waveguide. The interference pattern produced in the loop structure leaks outside of it and is guided in the plane waveguide to the photodetector array. This configuration allows one to control the shape of the field pattern at the end of the plane waveguide. A large fringe pattern with a high interference fringe contrast is obtained. A two-dimensional model based on an aperiodic Fourier modal method is used to modelize the coupling between the bent and the plane waveguides, completed with the Helmholtz-Kirchhoff propagation. This concept gives access to plan and compact spectrometers requiring only a single low-cost realization process step. The simulation has been done to realize a spectrometer in glass integrated optics (Deltalambda=6.1 nm at 1500 nm).

Static and Dynamic Behaviour Assessment of the Trajan Arch by Means of New Monitoring Technologies

NASA Astrophysics Data System (ADS)

Petti, L.; Barone, F.; Mammone, A.; Giordano, G.

2017-08-01

An effective assessment of the static and dynamic structural behavior of historical monuments requires the development and validation of suitable adaptive structural models using high-quality experimental data acquired with an effectively continuous and distributed monitoring. Furthermore, the adaptive strategy allows an efficient evaluation of the health status and of the evolution along the time of a historical monument, providing relevant information to plan appropriate actions for its long-term preservation. The Trajan Arch in Benevento chosen as a case of study to develop and apply this new adaptive strategy in cultural heritage conservation. The paper, after a description of the innovative monitoring system, based on state-of-the-art mechanical sensors, presents and discusses the results of two tests, comparing the measurements with the predictions of an adaptive structural FEM model developed for the dynamical simulation of the Trajan Arch.

Optical methods for non-contact measurements of membranes

NASA Astrophysics Data System (ADS)

Roose, S.; Stockman, Y.; Rochus, P.; Kuhn, T.; Lang, M.; Baier, H.; Langlois, S.; Casarosa, G.

2009-11-01

Structures for space applications very often suffer stringent mass constraints. Lightweight structures are developed for this purpose, through the use of deployable and/or inflatable beams, and thin-film membranes. Their inherent properties (low mass and small thickness) preclude the use of conventional measurement methods (accelerometers and displacement transducers for example) during on-ground testing. In this context, innovative non-contact measurement methods need to be investigated for these stretched membranes. The object of the present project is to review existing measurement systems capable of measuring characteristics of membrane space-structures such as: dot-projection videogrammetry (static measurements), stereo-correlation (dynamic and static measurements), fringe projection (wrinkles) and 3D laser scanning vibrometry (dynamic measurements). Therefore, minimum requirements were given for the study in order to have representative test articles covering a wide range of applications. We present test results obtained with the different methods on our test articles.

Cooperative macromolecular device revealed by meta-analysis of static and time-resolved structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Zhong; Šrajer, Vukica; Knapp, James E.

2013-04-08

Here we present a meta-analysis of a large collection of static structures of a protein in the Protein Data Bank in order to extract the progression of structural events during protein function. We apply this strategy to the homodimeric hemoglobin HbI from Scapharca inaequivalvis. We derive a simple dynamic model describing how binding of the first ligand in one of the two chemically identical subunits facilitates a second binding event in the other partner subunit. The results of our ultrafast time-resolved crystallographic studies support this model. We demonstrate that HbI functions like a homodimeric mechanical device, such as pliers ormore » scissors. Ligand-induced motion originating in one subunit is transmitted to the other via conserved pivot points, where the E and F' helices from two partner subunits are 'bolted' together to form a stable dimer interface permitting slight relative rotation but preventing sliding.« less

How to Obtain Accurate Equations-of-State by Eliminating the Effects of Deviatoric Stresses

NASA Astrophysics Data System (ADS)

Chesnut, Gary; Schiferl, David

2003-03-01

In the field of static high-pressure research, it is common to find disagreements in the data between individual experiments. For example, there are many disagreements about crystal structures and volume discontinuities at phase transitions. Of course, there are many causes that give rise to these problems. The intrinsic properties of some materials can be the source of the confusion. However, there is another source, which affects every static high-pressure experiment - deviatoric stress. This problem has been well defined in the last decade. In particular, A. K. Singh et al has derived the equations of the deviatoric stresses for all the crystallographic structures. However, it only takes a moment to realize the difficulty in solving these equations for all but the simplest structures. Fortunately, there is a way around the problem of deviatoric stress - Magic Angle X-ray Diffraction.

A numerical formulation and algorithm for limit and shakedown analysis of large-scale elastoplastic structures

NASA Astrophysics Data System (ADS)

Peng, Heng; Liu, Yinghua; Chen, Haofeng

2018-05-01

In this paper, a novel direct method called the stress compensation method (SCM) is proposed for limit and shakedown analysis of large-scale elastoplastic structures. Without needing to solve the specific mathematical programming problem, the SCM is a two-level iterative procedure based on a sequence of linear elastic finite element solutions where the global stiffness matrix is decomposed only once. In the inner loop, the static admissible residual stress field for shakedown analysis is constructed. In the outer loop, a series of decreasing load multipliers are updated to approach to the shakedown limit multiplier by using an efficient and robust iteration control technique, where the static shakedown theorem is adopted. Three numerical examples up to about 140,000 finite element nodes confirm the applicability and efficiency of this method for two-dimensional and three-dimensional elastoplastic structures, with detailed discussions on the convergence and the accuracy of the proposed algorithm.

Structural signal of a dynamic glass transition

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sudeshna; Uysal, Ahmet; Stripe, Benjamin; Evmenenko, Guennadi; Dutta, Pulak; Ehrlich, Steven; Karapetrova, Evguenia A.

2010-03-01

Conventional wisdom states that there is no significant difference between the static structures of the glass and liquid states of a given material. Using x-ray reflectivity, we have studied pentaphenyl trimethyl trisiloxane, an isotropic liquid at room temperature with a dynamic glass transition at 224K. Surface density oscillations (surface layers) develop below 285K, similar to those seen in other metallic and dielectric liquids and in computer simulations [1]. Upon cooling further, there is a sharp increase in the penetration of the surface layers into the bulk material, i.e. an apparently discontinuous change in the static structure, exactly at the glass transition (224K) [2]. [4pt] [1]. e.g. O. M. Magnussen et al., PRL 74, 4444 (1995); H. Mo et al. PRL 96, 096107 (2006); E. Chac'on et al., PRL 87, 166101 (2001) [0pt] [2] S. Chattopadhyay et al, PRL 103, 175701 (2009)

Design, analysis, and testing of the Phase 1 CSI Evolutionary Model erectable truss

NASA Technical Reports Server (NTRS)

Gronet, M. J.; Davis, D. A.; Kintis, D. H.; Brillhart, R. D.; Atkins, E. M.

1992-01-01

This report addressed the design, analysis, and testing of the erectable truss structure for the Phase 1 CSI Evolutionary Model (CEM) testbed. The Phase 1 CEM testbed is the second testbed to form part of an ongoing program of focused research at NASA/LaRC in the development of Controls-Structures Integration (CSI) technology. The Phase 1 CEM contains the same overall geometry, weight, and sensor locations as the Phase 0 CEM, but is based in an integrated controller and structure design, whereby both structure and controller design variables are sized simultaneously. The Phase 1 CEM design features seven truss sections composed of struts with tailored mass and stiffness properties. A common erectable joint is used and the strut stiffness is tailored by varying the cross-sectional area. To characterize the structure, static tests were conducted on individual struts and 10-bay truss assemblies. Dynamic tests were conducted on 10-bay truss assemblies as well as the fully-assembled CEM truss. The results indicate that the static and dynamic properties of the structure are predictable, well-characterized, and within the performance requirements established during the Phase 1 CEM integrated controller/structure design analysis.

Structural studies on choline-carboxylate bio-ionic liquids by x-ray scattering and molecular dynamics.

PubMed

Tanzi, Luana; Ramondo, Fabio; Caminiti, Ruggero; Campetella, Marco; Di Luca, Andrea; Gontrani, Lorenzo

2015-09-21

We report a X-ray diffraction and molecular dynamics study on three choline-based bio-ionic liquids, choline formate, [Ch] [For], choline propanoate, [Ch][Pro], and choline butanoate, [Ch][But]. For the first time, this class of ionic liquids has been investigated by X-ray diffraction. Experimental and theoretical structure factors have been compared for each term of the series. Local structural organization has been obtained from ab initio calculations through static models of isolated ion pairs and dynamic simulations of small portions of liquids through twelve, ten, and nine ion pairs for [Ch][For], [Ch][Pro], and [Ch][But], respectively. All the theoretical models indicate that cations and anions are connected by strong hydrogen bonding and form stable ion pairs in the liquid that are reminiscent of the static ab initio ion pairs. Different structural aspects may affect the radial distribution function, like the local structure of ion pairs and the conformation of choline. When small portions of liquids have been simulated by dynamic quantum chemical methods, some key structural features of the X-ray radial distribution function were well reproduced whereas the classical force fields here applied did not entirely reproduce all the observed structural features.

Structural studies on choline-carboxylate bio-ionic liquids by x-ray scattering and molecular dynamics

NASA Astrophysics Data System (ADS)

Tanzi, Luana; Ramondo, Fabio; Caminiti, Ruggero; Campetella, Marco; Di Luca, Andrea; Gontrani, Lorenzo

2015-09-01

We report a X-ray diffraction and molecular dynamics study on three choline-based bio-ionic liquids, choline formate, [Ch] [For], choline propanoate, [Ch][Pro], and choline butanoate, [Ch][But]. For the first time, this class of ionic liquids has been investigated by X-ray diffraction. Experimental and theoretical structure factors have been compared for each term of the series. Local structural organization has been obtained from ab initio calculations through static models of isolated ion pairs and dynamic simulations of small portions of liquids through twelve, ten, and nine ion pairs for [Ch][For], [Ch][Pro], and [Ch][But], respectively. All the theoretical models indicate that cations and anions are connected by strong hydrogen bonding and form stable ion pairs in the liquid that are reminiscent of the static ab initio ion pairs. Different structural aspects may affect the radial distribution function, like the local structure of ion pairs and the conformation of choline. When small portions of liquids have been simulated by dynamic quantum chemical methods, some key structural features of the X-ray radial distribution function were well reproduced whereas the classical force fields here applied did not entirely reproduce all the observed structural features.

Dynamic Fracture Toughness Evaluation by Measurement of CTOD (Crack Tip Opening Displacement).

DTIC Science & Technology

1988-03-15

fracture toughness of structural steels were reported by Shoemaker and Rolfe [1]; these and similar results are also presented in the text by Rolfe and...8217 MPaV/-m/s. Following the dynamic tests of Shoemaker and Rolfe , extensions of the familiar ASTM E-399 static fracture toughness tests were examined. This...s.V.: **.4* .4 5, -~ 5 5 - 𔃿 .4.4 References [1] Shoemaker, A.K. and Rolfe , S.T., "The Static and Dynamic Low-Temperature Crack-Toughness

Experimental Investigation of Stiffness Characteristics and Damping Properties of a Metallic Rubber Material

NASA Astrophysics Data System (ADS)

Lu, Ch. Zh.; Li, Jingyuan; Zhou, Bangyang; Li, Shuang

2017-09-01

The static stiffness and dynamic damping properties of a metallic rubber material (MR) were investigated, which exhibited a nonlinear deformation behavior. Its static stiffness is analyzed and discussed. The effects of structural parameters of MR and experimental conditions on its shock absorption capacity were examined by dynamic tests. Results revealed excellent elastic and damping properties of the material. Its stiffness increased with density, but decreased with thickness. The damping property of MR varied with its density, thickness, loading frequency, and amplitude.

Proceedings of the conference on energy conservation: Retrofit of Municipal Wastewater Treatment Facilities

NASA Astrophysics Data System (ADS)

1982-02-01

The concepts of the roles of heat and temperature, ventilation and water removal when organic material is assembled into a self insulating mass are summarized. The practical application of these concepts in static pile configuration or the Rutgers process are outlined. The concepts and means of application are relevant to all design approaches whether or not a reactor structure is involved, whether the process is batch or continuous, and whether the mass is agitated or static.

Evaluation of Aero Commander sidewall vibration and interior acoustic data: Static operations

NASA Technical Reports Server (NTRS)

Piersol, A. G.; Wilby, E. G.; Wilby, J. F.

1980-01-01

Results for the vibration measured at five locations on the fuselage structure during static operations are presented. The analysis was concerned with the magnitude of the vibration and the relative phase between different locations, the frequency response (inertance) functions between the exterior pressure field and the vibration, and the coherent output power functions at interior microphone locations based on sidewall vibration. Fuselage skin panels near the plane of rotation of the propeller accept propeller noise excitation more efficiently than they do exhaust noise.

Implementation of structural response sensitivity calculations in a large-scale finite-element analysis system

NASA Technical Reports Server (NTRS)

Giles, G. L.; Rogers, J. L., Jr.

1982-01-01

The implementation includes a generalized method for specifying element cross-sectional dimensions as design variables that can be used in analytically calculating derivatives of output quantities from static stress, vibration, and buckling analyses for both membrane and bending elements. Limited sample results for static displacements and stresses are presented to indicate the advantages of analytically calclating response derivatives compared to finite difference methods. Continuing developments to implement these procedures into an enhanced version of the system are also discussed.

Some studies on the use of NASTRAN for nuclear power plant structural analysis and design

NASA Technical Reports Server (NTRS)

Setlur, A. V.; Valathur, M.

1973-01-01

Studies made on the use of NASTRAN for nuclear power plant analysis and design are presented. These studies indicate that NASTRAN could be effectively used for static, dynamic and special purpose problems encountered in the design of such plants. Normal mode capability of NASTRAN is extended through a post-processor program to handle seismic analysis. Static and dynamic substructuring is discussed. Extension of NASTRAN to include the needs in the civil engineering industry is discussed.

Radio jet refraction in galactic atmospheres with static pressure gradients

NASA Technical Reports Server (NTRS)

Henriksen, R. N.; Vallee, J. P.; Bridle, A. H.

1981-01-01

A theory based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy, is proposed for double radio sources with a Z or S morphology. The model describes a collimated jet of supersonic material that bends self-consistently under the influence of external static pressure gradients, and may alternatively be seen as a continuous-jet version of the buoyancy model proposed by Gull (1973). Emphasis is placed on (1) S-shaped radio sources identified with isolated galaxies, such as 3C 293, whose radio structures should be free of distortions resulting from motion relative to a cluster medium, and (2) small-scale, galaxy-dominated rather than environment-dominated S-shaped sources such as the inner jet structure of Fornax A.

Drawing simulation by static implicit analysis with the artificial damping method

NASA Astrophysics Data System (ADS)

Oide, K.; Mihara, Y.; Kobayashi, T.; Takizawa, H.; Amaishi, T.; Umezu, Y.

2016-08-01

Wrinkling during draw is typically a local instability problem. When the structural instability is localized, there will be a local transfer of strain energy from one part of the structure to neighboring parts, and global solution methods, which is typically represented by the arc length method, may not work. So, this type of problems has to be solved either dynamically or with the artificial damping. On the other hand, the essential nature of the buckling behavior can be regarded as a static problem, even though it may be possible to raise some side issues due to the inertia effect. In this study, we traced the local buckling behavior of anisotropic elasto-plastic thin shells in Numisheet2014 BM4 using the artificial damping method.

Photogrammetry and Videogrammetry Methods Development for Solar Sail Structures. Masters Thesis awarded by George Washington Univ.

NASA Technical Reports Server (NTRS)

Pappa, Richard S. (Technical Monitor); Black, Jonathan T.

2003-01-01

This report discusses the development and application of metrology methods called photogrammetry and videogrammetry that make accurate measurements from photographs. These methods have been adapted for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, non-contact, dynamic characterization using dot projection videogrammetry. The accuracy of the measurement of the resonant frequencies and operating deflection shapes that were extracted surpassed expectations. While other non-contact measurement methods exist, they are not full-field and require significantly more time to take data.

Chemical complexity induced local structural distortion in NiCoFeMnCr high-entropy alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Fuxiang; Tong, Yang; Jin, Ke

In order to study chemical complexity-induced lattice distortion in high-entropy alloys, the static Debye–Waller (D-W) factor of NiCoFeMnCr solid solution alloy is measured with low temperature neutron diffraction, ambient X-ray diffraction, and total scattering methods. Here, the static atomic displacement parameter of the multi-element component alloy at 0 K is 0.035–0.041 Å, which is obvious larger than that of element Ni (~0 Å). The atomic pair distance between individual atoms in the alloy investigated with extended X-ray absorption fine structure (EXAFS) measurements indicates that Mn has a slightly larger bond distance (~0.4%) with neighbor atoms than that of others.

Chemical complexity induced local structural distortion in NiCoFeMnCr high-entropy alloy

DOE PAGES

Zhang, Fuxiang; Tong, Yang; Jin, Ke; ...

2018-06-16

In order to study chemical complexity-induced lattice distortion in high-entropy alloys, the static Debye–Waller (D-W) factor of NiCoFeMnCr solid solution alloy is measured with low temperature neutron diffraction, ambient X-ray diffraction, and total scattering methods. Here, the static atomic displacement parameter of the multi-element component alloy at 0 K is 0.035–0.041 Å, which is obvious larger than that of element Ni (~0 Å). The atomic pair distance between individual atoms in the alloy investigated with extended X-ray absorption fine structure (EXAFS) measurements indicates that Mn has a slightly larger bond distance (~0.4%) with neighbor atoms than that of others.

Targeted Maximum Likelihood Estimation for Dynamic and Static Longitudinal Marginal Structural Working Models

PubMed Central

Schwab, Joshua; Gruber, Susan; Blaser, Nello; Schomaker, Michael; van der Laan, Mark

2015-01-01

This paper describes a targeted maximum likelihood estimator (TMLE) for the parameters of longitudinal static and dynamic marginal structural models. We consider a longitudinal data structure consisting of baseline covariates, time-dependent intervention nodes, intermediate time-dependent covariates, and a possibly time-dependent outcome. The intervention nodes at each time point can include a binary treatment as well as a right-censoring indicator. Given a class of dynamic or static interventions, a marginal structural model is used to model the mean of the intervention-specific counterfactual outcome as a function of the intervention, time point, and possibly a subset of baseline covariates. Because the true shape of this function is rarely known, the marginal structural model is used as a working model. The causal quantity of interest is defined as the projection of the true function onto this working model. Iterated conditional expectation double robust estimators for marginal structural model parameters were previously proposed by Robins (2000, 2002) and Bang and Robins (2005). Here we build on this work and present a pooled TMLE for the parameters of marginal structural working models. We compare this pooled estimator to a stratified TMLE (Schnitzer et al. 2014) that is based on estimating the intervention-specific mean separately for each intervention of interest. The performance of the pooled TMLE is compared to the performance of the stratified TMLE and the performance of inverse probability weighted (IPW) estimators using simulations. Concepts are illustrated using an example in which the aim is to estimate the causal effect of delayed switch following immunological failure of first line antiretroviral therapy among HIV-infected patients. Data from the International Epidemiological Databases to Evaluate AIDS, Southern Africa are analyzed to investigate this question using both TML and IPW estimators. Our results demonstrate practical advantages of the pooled TMLE over an IPW estimator for working marginal structural models for survival, as well as cases in which the pooled TMLE is superior to its stratified counterpart. PMID:25909047

Ab initio study of the structure and dynamics of bulk liquid Fe

NASA Astrophysics Data System (ADS)

Marqués, M.; González, L. E.; González, D. J.

2015-10-01

Several static and dynamic properties of bulk liquid Fe at a thermodynamic state near its triple point have been evaluated by ab initio molecular dynamics simulations. The calculated static structure shows very good agreement with the available experimental data, including an asymmetric second peak in the structure factor which underlines a substantial local icosahedral short-range order in the liquid. The dynamical structure reveals propagating density fluctuations, with an associated dispersion relation which closely follows the experimental data. The dynamic structure factors S (q ,ω ) show a good agreement with their experimental counterparts which have been recently measured by an inelastic x-ray scattering experiment. The dynamical processes behind the S (q ,ω ) have been analyzed by using a model with two decay channels (a fast and a slow) associated with the relaxations of the collective excitations. The recent finding of transverselike excitation modes in the IXS data is analyzed by using the present ab initio simulation results. Several transport coefficients have been evaluated and the results are compared with the available experimental data.

Dynamic analysis of the BMW tower in Munich

NASA Astrophysics Data System (ADS)

Indacochea-Beltran, Joaquin; Elgindy, Pearl; Lee, Elaine; Vignesh, Thiviya; Ansourian, Peter; Tahmasebinia, Faham; Marroquín, Fernando Alonso

2016-08-01

In the 1970s, world famous Austrian architect Karl Schwanzer designed an avant-garde suspended skyscraper for the new BMW headquarters. The BMW Tower was envisioned to resemble a four-cylinder motor and become a symbol for the recent flourishing success of BMW. Throughout its four decades, the BMW Tower has become the main architectural feature of modern Munich and a pride for one of the World leading car manufacturers. The structural design of the BMW Tower represented a major challenge to Germany's finest engineers because the suspended 99.5m-high structure had to whitstand not only static loading but large wind dynamic loading while having deflections within appropriate serviceability limits. Strand7 has been used to determine the stresses and deflections the structure is subjected to in order to analyse its behavior under static and dynamic loadings. Ultimately, this analysis helps to understand the nature of suspended structures in relation to the Eurocode building standards. Finally, thermal resistance has also been analysed using Strand7 to simulate a fire scenario and analyse the behaviour of the cable structure, which is the most critical building component.

Analysis of frame structure of medium and small truck crane

NASA Astrophysics Data System (ADS)

Cao, Fuyi; Li, Jinlong; Cui, Mengkai

2018-03-01

Truck crane is an important part of hoisting machinery. Frame, as the support component of the quality of truck crane, determines the safety of crane jib load and the rationality of structural design. In this paper, the truck crane frame is a box structure, the three-dimensional model is established in CATIA software, and imported into Hyperworks software for finite element analysis. On the base of doing constraints and loads for the finite element model of the frame, the finite element static analysis is carried out. And the static stress test verifies whether the finite element model and the frame structure design are reasonable; then the free modal analysis of the frame and the analysis of the first 8 - order modal vibration deformation are carried out. The analysis results show that the maximum stress value of the frame is greater than the yield limit value of the material, and the low-order modal value is close to the excitation frequency value, which needs to be improved to provide theoretical reference for the structural design of the truck crane frame.

Modeling, estimation and identification methods for static shape determination of flexible structures. [for large space structure design

NASA Technical Reports Server (NTRS)

Rodriguez, G.; Scheid, R. E., Jr.

1986-01-01

This paper outlines methods for modeling, identification and estimation for static determination of flexible structures. The shape estimation schemes are based on structural models specified by (possibly interconnected) elliptic partial differential equations. The identification techniques provide approximate knowledge of parameters in elliptic systems. The techniques are based on the method of maximum-likelihood that finds parameter values such that the likelihood functional associated with the system model is maximized. The estimation methods are obtained by means of a function-space approach that seeks to obtain the conditional mean of the state given the data and a white noise characterization of model errors. The solutions are obtained in a batch-processing mode in which all the data is processed simultaneously. After methods for computing the optimal estimates are developed, an analysis of the second-order statistics of the estimates and of the related estimation error is conducted. In addition to outlining the above theoretical results, the paper presents typical flexible structure simulations illustrating performance of the shape determination methods.

NASTRAN: User's Experiences

NASA Technical Reports Server (NTRS)

1976-01-01

The application of NASTRAN to a wide variety of static and dynamic structural problems is discussed. The following topics are focused upon: (1) methods of analysis; (2) hydroelastic methods; (3) complete analysis of structures; (4) elements and material studies; (5) critical comparisons with other programs; and (6) pre- and post-processor operations.

MaxEnt-Based Ecological Theory: A Template for Integrated Catchment Theory

NASA Astrophysics Data System (ADS)

Harte, J.

2017-12-01

The maximum information entropy procedure (MaxEnt) is both a powerful tool for inferring least-biased probability distributions from limited data and a framework for the construction of complex systems theory. The maximum entropy theory of ecology (METE) describes remarkably well widely observed patterns in the distribution, abundance and energetics of individuals and taxa in relatively static ecosystems. An extension to ecosystems undergoing change in response to disturbance or natural succession (DynaMETE) is in progress. I describe the structure of both the static and the dynamic theory and show a range of comparisons with census data. I then propose a generalization of the MaxEnt approach that could provide a framework for a predictive theory of both static and dynamic, fully-coupled, eco-socio-hydrological catchment systems.

An investigation into the probabilistic combination of quasi-static and random accelerations

NASA Technical Reports Server (NTRS)

Schock, R. W.; Tuell, L. P.

1984-01-01

The development of design load factors for aerospace and aircraft components and experiment support structures, which are subject to a simultaneous vehicle dynamic vibration (quasi-static) and acoustically generated random vibration, require the selection of a combination methodology. Typically, the procedure is to define the quasi-static and the random generated response separately, and arithmetically add or root sum square to get combined accelerations. Since the combination of a probabilistic and a deterministic function yield a probabilistic function, a viable alternate approach would be to determine the characteristics of the combined acceleration probability density function and select an appropriate percentile level for the combined acceleration. The following paper develops this mechanism and provides graphical data to select combined accelerations for most popular percentile levels.

Reactivity of seismicity rate to static Coulomb stress changes of two consecutive large earthquakes in the central Philippines

NASA Astrophysics Data System (ADS)

Dianala, J. D. B.; Aurelio, M.; Rimando, J. M.; Taguibao, K.

2015-12-01

In a region with little understanding in terms of active faults and seismicity, two large-magnitude reverse-fault related earthquakes occurred within 100km of each other in separate islands of the Central Philippines—the Mw=6.7 February 2012 Negros earthquake and the Mw=7.2 October 2013 Bohol earthquake. Based on source faults that were defined using onshore, offshore seismic reflection, and seismicity data, stress transfer models for both earthquakes were calculated using the software Coulomb. Coulomb stress triggering between the two main shocks is unlikely as the stress change caused by Negros earthquake on the Bohol fault was -0.03 bars. Correlating the stress changes on optimally-oriented reverse faults with seismicity rate changes shows that areas that decreased both in static stress and seismicity rate after the first earthquake were then areas with increased static stress and increased seismicity rate caused by the second earthquake. These areas with now increased stress, especially those with seismicity showing reactivity to static stress changes caused by the two earthquakes, indicate the presence of active structures in the island of Cebu. Comparing the history of instrumentally recorded seismicity and the recent large earthquakes of Negros and Bohol, these structures in Cebu have the potential to generate large earthquakes. Given that the Philippines' second largest metropolitan area (Metro Cebu) is in close proximity, detailed analysis of the earthquake potential and seismic hazards in these areas should be undertaken.

Framework for Querying and Analysis of Evolving Graphs

ERIC Educational Resources Information Center

Moffitt, Vera Zaychik

2017-01-01

Graph representations underlie many modern computer applications, capturing the structure of such diverse networks as the Internet, personal associations, roads, sensors, and metabolic pathways. While the static structure of graphs is a well-explored field, a new emphasis is being placed on understanding and representing the way these networks…

Sixteenth NASTRAN (R) Users' Colloquium

NASA Technical Reports Server (NTRS)

1988-01-01

These are the proceedings of the Sixteenth NASTRAN Users' Colloquium held in Arlington, Virginia from 25 to 29 April, 1988. Technical papers contributed by participants review general application of finite element methodology and the specific application of the NASA Structural Analysis System (NASTRAN) to a variety of static and dynamic structural problems.

Meteorological Satellites (METSAT) and Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) Stress Analysis Report

NASA Technical Reports Server (NTRS)

Heffner, Robert

1996-01-01

Stress analysis of the primary structure of the Meteorological Satellites Project (METSAT) Advanced Microwave Sounding Units-A, A1 Module using static loads is presented. The structural margins of safety and natural frequency predictions for the METSAT design are reported.

77 FR 19567 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... aeroplanes listed in the applicability section of this [EASA] AD. Static, fatigue and corrosion tests were... detect and correct cracked nuts on the fuselage which could result in reduced structural integrity of the... products. The MCAI states: During structural part assembly in Airbus production line, some nuts Part Number...

Sensitivity analysis for large-scale problems

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Whitworth, Sandra L.

1987-01-01

The development of efficient techniques for calculating sensitivity derivatives is studied. The objective is to present a computational procedure for calculating sensitivity derivatives as part of performing structural reanalysis for large-scale problems. The scope is limited to framed type structures. Both linear static analysis and free-vibration eigenvalue problems are considered.

Noninvasive metabolic imaging of engineered 3D human adipose tissue in a perfusion bioreactor.

PubMed

Ward, Andrew; Quinn, Kyle P; Bellas, Evangelia; Georgakoudi, Irene; Kaplan, David L

2013-01-01

The efficacy and economy of most in vitro human models used in research is limited by the lack of a physiologically-relevant three-dimensional perfused environment and the inability to noninvasively quantify the structural and biochemical characteristics of the tissue. The goal of this project was to develop a perfusion bioreactor system compatible with two-photon imaging to noninvasively assess tissue engineered human adipose tissue structure and function in vitro. Three-dimensional (3D) vascularized human adipose tissues were engineered in vitro, before being introduced to a perfusion environment and tracked over time by automated quantification of endogenous markers of metabolism using two-photon excited fluorescence (TPEF). Depth-resolved image stacks were analyzed for redox ratio metabolic profiling and compared to prior analyses performed on 3D engineered adipose tissue in static culture. Traditional assessments with H&E staining were used to qualitatively measure extracellular matrix generation and cell density with respect to location within the tissue. The distribution of cells within the tissue and average cellular redox ratios were different between static and perfusion cultures, while the trends of decreased redox ratio and increased cellular proliferation with time in both static and perfusion cultures were similar. These results establish a basis for noninvasive optical tracking of tissue structure and function in vitro, which can be applied to future studies to assess tissue development or drug toxicity screening and disease progression.

NASA-approved rotary bioreactor enhances proliferation of human epidermal stem cells and supports formation of 3D epidermis-like structure.

PubMed

Lei, Xiao-hua; Ning, Li-na; Cao, Yu-jing; Liu, Shuang; Zhang, Shou-bing; Qiu, Zhi-fang; Hu, Hui-min; Zhang, Hui-shan; Liu, Shu; Duan, En-kui

2011-01-01

The skin is susceptible to different injuries and diseases. One major obstacle in skin tissue engineering is how to develop functional three-dimensional (3D) substitute for damaged skin. Previous studies have proved a 3D dynamic simulated microgravity (SMG) culture system as a "stimulatory" environment for the proliferation and differentiation of stem cells. Here, we employed the NASA-approved rotary bioreactor to investigate the proliferation and differentiation of human epidermal stem cells (hEpSCs). hEpSCs were isolated from children foreskins and enriched by collecting epidermal stem cell colonies. Cytodex-3 micro-carriers and hEpSCs were co-cultured in the rotary bioreactor and 6-well dish for 15 days. The result showed that hEpSCs cultured in rotary bioreactor exhibited enhanced proliferation and viability surpassing those cultured in static conditions. Additionally, immunostaining analysis confirmed higher percentage of ki67 positive cells in rotary bioreactor compared with the static culture. In contrast, comparing with static culture, cells in the rotary bioreactor displayed a low expression of involucrin at day 10. Histological analysis revealed that cells cultured in rotary bioreactor aggregated on the micro-carriers and formed multilayer 3D epidermis structures. In conclusion, our research suggests that NASA-approved rotary bioreactor can support the proliferation of hEpSCs and provide a strategy to form multilayer epidermis structure.

Rapid iterative reanalysis for automated design

NASA Technical Reports Server (NTRS)

Bhatia, K. G.

1973-01-01

A method for iterative reanalysis in automated structural design is presented for a finite-element analysis using the direct stiffness approach. A basic feature of the method is that the generalized stiffness and inertia matrices are expressed as functions of structural design parameters, and these generalized matrices are expanded in Taylor series about the initial design. Only the linear terms are retained in the expansions. The method is approximate because it uses static condensation, modal reduction, and the linear Taylor series expansions. The exact linear representation of the expansions of the generalized matrices is also described and a basis for the present method is established. Results of applications of the present method to the recalculation of the natural frequencies of two simple platelike structural models are presented and compared with results obtained by using a commonly applied analysis procedure used as a reference. In general, the results are in good agreement. A comparison of the computer times required for the use of the present method and the reference method indicated that the present method required substantially less time for reanalysis. Although the results presented are for relatively small-order problems, the present method will become more efficient relative to the reference method as the problem size increases. An extension of the present method to static reanalysis is described, ana a basis for unifying the static and dynamic reanalysis procedures is presented.

Assimilating uncertain, dynamic and intermittent streamflow observations in hydrological models

NASA Astrophysics Data System (ADS)

Mazzoleni, Maurizio; Alfonso, Leonardo; Chacon-Hurtado, Juan; Solomatine, Dimitri

2015-09-01

Catastrophic floods cause significant socio-economical losses. Non-structural measures, such as real-time flood forecasting, can potentially reduce flood risk. To this end, data assimilation methods have been used to improve flood forecasts by integrating static ground observations, and in some cases also remote sensing observations, within water models. Current hydrologic and hydraulic research works consider assimilation of observations coming from traditional, static sensors. At the same time, low-cost, mobile sensors and mobile communication devices are becoming also increasingly available. The main goal and innovation of this study is to demonstrate the usefulness of assimilating uncertain streamflow observations that are dynamic in space and intermittent in time in the context of two different semi-distributed hydrological model structures. The developed method is applied to the Brue basin, where the dynamic observations are imitated by the synthetic observations of discharge. The results of this study show how model structures and sensors locations affect in different ways the assimilation of streamflow observations. In addition, it proves how assimilation of such uncertain observations from dynamic sensors can provide model improvements similar to those of streamflow observations coming from a non-optimal network of static physical sensors. This can be a potential application of recent efforts to build citizen observatories of water, which can make the citizens an active part in information capturing, evaluation and communication, helping simultaneously to improvement of model-based flood forecasting.

HCV RNA traffic and association with NS5A in living cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiches, Guillaume N.; Eyre, Nicholas S.; Aloia, Amanda L.

The spatiotemporal dynamics of Hepatitis C Virus (HCV) RNA localisation are poorly understood. To address this we engineered HCV genomes harbouring MS2 bacteriophage RNA stem-loops within the 3′-untranslated region to allow tracking of HCV RNA via specific interaction with a MS2-Coat-mCherry fusion protein. Despite the impact of these insertions on viral fitness, live imaging revealed that replication of tagged-HCV genomes induced specific redistribution of the mCherry-tagged-MS2-Coat protein to motile and static foci. Further analysis showed that HCV RNA was associated with NS5A in both static and motile structures while a subset of motile NS5A structures was devoid of HCV RNA.more » Further investigation of viral RNA traffic with respect to lipid droplets (LDs) revealed HCV RNA-positive structures in close association with LDs. These studies provide new insights into the dynamics of HCV RNA traffic with NS5A and LDs and provide a platform for future investigations of HCV replication and assembly. - Highlights: • HCV can tolerate can bacteriophage MS2 stem-loop insertions within the 3′ UTR. • MS2 stem-loop containing HCV genomes allow for real-time imaging of HCV RNA. • HCV RNA is both static and motile and associates with NS5A and lipid droplets.« less

Dispersed Sensing Networks in Nano-Engineered Polymer Composites: From Static Strain Measurement to Ultrasonic Wave Acquisition

PubMed Central

Li, Yehai; Wang, Kai

2018-01-01

Self-sensing capability of composite materials has been the core of intensive research over the years and particularly boosted up by the recent quantum leap in nanotechnology. The capacity of most existing self-sensing approaches is restricted to static strains or low-frequency structural vibration. In this study, a new breed of functionalized epoxy-based composites is developed and fabricated, with a graphene nanoparticle-enriched, dispersed sensing network, whereby to self-perceive broadband elastic disturbance from static strains, through low-frequency vibration to guided waves in an ultrasonic regime. Owing to the dispersed and networked sensing capability, signals can be captured at any desired part of the composites. Experimental validation has demonstrated that the functionalized composites can self-sense strains, outperforming conventional metal foil strain sensors with a significantly enhanced gauge factor and a much broader response bandwidth. Precise and fast self-response of the composites to broadband ultrasonic signals (up to 440 kHz) has revealed that the composite structure itself can serve as ultrasound sensors, comparable to piezoceramic sensors in performance, whereas avoiding the use of bulky cables and wires as used in a piezoceramic sensor network. This study has spotlighted promising potentials of the developed approach to functionalize conventional composites with a self-sensing capability of high-sensitivity yet minimized intrusion to original structures. PMID:29724032

Method of thermally processing superplastically formed aluminum-lithium alloys to obtain optimum strengthening

NASA Technical Reports Server (NTRS)

Anton, Claire E. (Inventor)

1993-01-01

Optimum strengthening of a superplastically formed aluminum-lithium alloy structure is achieved via a thermal processing technique which eliminates the conventional step of solution heat-treating immediately following the step of superplastic forming of the structure. The thermal processing technique involves quenching of the superplastically formed structure using static air, forced air or water quenching.

Post-earthquake relaxation using a spectral element method: 2.5-D case

USGS Publications Warehouse

Pollitz, Fred

2014-01-01

The computation of quasi-static deformation for axisymmetric viscoelastic structures on a gravitating spherical earth is addressed using the spectral element method (SEM). A 2-D spectral element domain is defined with respect to spherical coordinates of radius and angular distance from a pole of symmetry, and 3-D viscoelastic structure is assumed to be azimuthally symmetric with respect to this pole. A point dislocation source that is periodic in azimuth is implemented with a truncated sequence of azimuthal order numbers. Viscoelasticity is limited to linear rheologies and is implemented with the correspondence principle in the Laplace transform domain. This leads to a series of decoupled 2-D problems which are solved with the SEM. Inverse Laplace transform of the independent 2-D solutions leads to the time-domain solution of the 3-D equations of quasi-static equilibrium imposed on a 2-D structure. The numerical procedure is verified through comparison with analytic solutions for finite faults embedded in a laterally homogeneous viscoelastic structure. This methodology is applicable to situations where the predominant structure varies in one horizontal direction, such as a structural contrast across (or parallel to) a long strike-slip fault.

Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches

NASA Astrophysics Data System (ADS)

Chróścielewski, Jacek; Schmidt, Rüdiger; Eremeyev, Victor A.

2018-05-01

This paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite rotations of the normal. The finite element model can be applied to static, stability, and transient analysis of smart structures consisting of a master structure and integrated piezoelectric actuator layers or patches attached to the upper and lower surfaces. Two problems are studied extensively: (i) FE analyses of a clamped semicircular ring shell that has been used as a benchmark problem for linear vibration control in several recent papers are critically reviewed and extended to account for the effects of structural nonlinearity and (ii) a smart circular arch subjected to a hydrostatic pressure load is investigated statically and dynamically in order to study the shift of bifurcation and limit points, eigenfrequencies, and eigenvectors, as well as vibration control for loading conditions which may lead to dynamic loss of stability.

Volatile release from self-assembly structured emulsions: effect of monoglyceride content, oil content, and oil type.

PubMed

Mao, Like; Roos, Yrjö H; Miao, Song

2013-02-20

Monoglycerides (MGs) can form self-assembled structures in emulsions, which can be used to control volatile release. In this study, initial headspace concentrations (C(initial)), maximum headspace concentrations (C(max)), release rates, and partition coefficients of propanol, diacetyl, hexanal, and limonene were determined in MG structured oil-in-water emulsions using dynamic and static headspace analyses. For all of the volatile compounds, C(initial) values above structured emulsions were significantly lower than those above unstructured emulsions and decreased with increasing MG contents (p < 0.05). However, volatiles had higher release rates in emulsions with higher MG contents. When oil content was reduced from 20 to 10%, C(initial) and C(max) increased for limonene and hexanal and decreased for propanol and diacetyl. When different oils were applied, both C(initial) and C(max) were significantly lower in medium-chain triglyceride emulsions than in soybean oil emulsions (p < 0.05). Static headspace analysis revealed that volatile compounds had significantly lower air-emulsion partition coefficients in the structured emulsions than in unstructured emulsions (p < 0.05). These results indicated that MG structured emulsions can be potentially used as delivery systems to modulate volatile release.

Coda Wave Interferometry Method Applied in Structural Monitoring to Assess Damage Evolution in Masonry and Concrete Structures

NASA Astrophysics Data System (ADS)

Masera, D.; Bocca, P.; Grazzini, A.

2011-07-01

In this experimental program the main goal is to monitor the damage evolution in masonry and concrete structures by Acoustic Emission (AE) signal analysis applying a well-know seismic method. For this reason the concept of the coda wave interferometry is applied to AE signal recorded during the tests. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced masonry walls under variable amplitude loading and strengthening reinforced concrete (RC) beams under monotonic static load has been carried out. In the reinforced masonry wall, cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of masonry under static long-time loading. During the tests, the evaluation of fracture growth is monitored by coda wave interferometry which represents a novel approach in structural monitoring based on AE relative change velocity of coda signal. In general, the sensitivity of coda waves has been used to estimate velocity changes in fault zones, in volcanoes, in a mining environment, and in ultrasound experiments. This method uses multiple scattered waves, which travelled through the material along numerous paths, to infer tiny temporal changes in the wave velocity. The applied method has the potential to be used as a "damage-gauge" for monitoring velocity changes as a sign of damage evolution into masonry and concrete structures.

Do dynamic cement-on-cement knee spacers provide better function and activity during two-stage exchange?

PubMed

Jaekel, David J; Day, Judd S; Klein, Gregg R; Levine, Harlan; Parvizi, Javad; Kurtz, Steven M

2012-09-01

Implantation of an antibiotic bone cement spacer is used to treat infection of a TKA. Dynamic spacers fashioned with cement-on-cement articulating surfaces potentially facilitate patient mobility and reduce bone loss as compared with their static counterparts, while consisting of a biomaterial not traditionally used for load-bearing articulations. However, their direct impact on patient mobility and wear damage while implanted remains poorly understood. We characterized patient activity, surface damage, and porous structure of dynamic cement-on-cement spacers. We collected 22 dynamic and 14 static knee antibiotic cement spacers at revision surgeries at times ranging from 0.5 to 13 months from implantation. For these patients, we obtained demographic data and UCLA activity levels. We characterized surface damage using the Hood damage scoring method and used micro-CT analysis to observe the internal structure, cracking, and porosity of the cement. The average UCLA score was higher for patients with dynamic spacers than for patients with static spacers, with no differences in BMI or age. Burnishing was the only prevalent damage mode on all the bearing surfaces. Micro-CT analysis revealed the internal structure of the spacers was porous and highly inhomogeneous, including heterogeneous dispersion of radiopaque material and cavity defects. The average porosity was 8% (range, 1%-29%) and more than ½ of the spacers had pores greater than 1 mm in diameter. Our observations suggest dynamic, cement-on-cement spacers allow for increased patient activity without catastrophic failure. Despite the antibiotic loading and internal structural inhomogeneity, burnishing was the only prevalent damage mode that could be consistently classified with no evidence of fracture or delamination. The porous structure of the spacers varied highly across the surfaces without influencing the material failure.

The NASTRAN theoretical manual

NASA Technical Reports Server (NTRS)

1981-01-01

Designed to accommodate additions and modifications, this commentary on NASTRAN describes the problem solving capabilities of the program in a narrative fashion and presents developments of the analytical and numerical procedures that underlie the program. Seventeen major sections and numerous subsections cover; the organizational aspects of the program, utility matrix routines, static structural analysis, heat transfer, dynamic structural analysis, computer graphics, special structural modeling techniques, error analysis, interaction between structures and fluids, and aeroelastic analysis.