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Sample records for ire1p er-stress transducer

  1. Stress sensing in plants by the ER stress sensor/transducer, bZIP28

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    Renu eSrivastava

    2014-02-01

    Full Text Available Two classes of ER stress sensors are known in plants, membrane associated bZIP transcription factors and RNA splicing factors. ER stress occurs under adverse environmental conditions and results from the accumulation of misfolded or unfolded proteins in the ER lumen. One of the membrane-associated transcription factors activated by heat and ER stress agents is bZIP28. In its inactive form, bZIP28 is a type II protein with a single pass transmembrane domain, residing in the ER. bZIP28’s N-terminus, containing a transcriptional activation domain, is oriented towards the cytoplasm and its C-terminal tail is inserted into the ER lumen. In response to stress, bZIP28 exits the ER and moves to the Golgi where it is proteolytically processed, liberating its cytosolic component which relocates to the nucleus to upregulate stress-response genes. bZIP28 is thought to sense stress through its interaction with the major ER chaperone, BIP. BiP binds to bZIP28’s lumenal domain under unstressed conditions and retains it in the ER. BIP binds to the intrinsically disordered regions on bZIP28’s lumen-facing tail. A truncated form of bZIP28, without its C-terminal tail is not retained in the ER but migrates constitutively to the nucleus. Upon stress, BiP releases bZIP28 allowing it to exit the ER. One model to account for the release of bZIP28 by BiP is that BiP is competed away from bZIP28 by the accumulation of misfolded proteins in the ER. However, other forces such as changes in energy charge levels, redox conditions or interaction with DNAJ proteins may also promote release of bZIP28 from BiP. Movement of bZIP28 from the ER to the Golgi is assisted by the interaction of elements of the COPII machinery with the cytoplasmic domain of bZIP28. Thus, the mobilization of bZIP28 in response to stress involves the dissociation of factors that retain it in the ER and the association of factors that mediate its further organelle-to-organelle movement.

  2. ER Stress and Lipid Metabolism in Adipocytes

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    Beth S. Zha

    2012-01-01

    Full Text Available The role of endoplasmic reticulum (ER stress is a rapidly emerging field of interest in the pathogenesis of metabolic diseases. Recent studies have shown that chronic activation of ER stress is closely linked to dysregulation of lipid metabolism in several metabolically important cells including hepatocytes, macrophages, β-cells, and adipocytes. Adipocytes are one of the major cell types involved in the pathogenesis of the metabolic syndrome. Recent advances in dissecting the cellular and molecular mechanisms involved in the regulation of adipogenesis and lipid metabolism indicate that activation of ER stress plays a central role in regulating adipocyte function. In this paper, we discuss the current understanding of the potential role of ER stress in lipid metabolism in adipocytes. In addition, we touch upon the interaction of ER stress and autophagy as well as inflammation. Inhibition of ER stress has the potential of decreasing the pathology in adipose tissue that is seen with energy overbalance.

  3. Endoplasmic Reticulum (ER Stress and Endocrine Disorders

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    Daisuke Ariyasu

    2017-02-01

    Full Text Available The endoplasmic reticulum (ER is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR, which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI, Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2 are discussed in this article.

  4. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

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    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-01-01

    The endoplasmic reticulum (ER) is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR), which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI), Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2) are discussed in this article. PMID:28208663

  5. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

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    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  6. Arctigenin alleviates ER stress via activating AMPK

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    Gu, Yuan; Sun, Xiao-xiao; Ye, Ji-ming; He, Li; Yan, Shou-sheng; Zhang, Hao-hao; Hu, Li-hong; Yuan, Jun-ying; Yu, Qiang

    2012-01-01

    Aim: To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms. Methods: A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKβ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels. Results: ATG (2.5, 5 and 10 μmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 μmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 μmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 μmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 μmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 β cells. Conclusion: ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load. PMID:22705729

  7. Coronavirus infection, ER stress and Apoptosis

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    TO SING eFUNG

    2014-06-01

    Full Text Available The replication of coronavirus, a family of important animal and human pathogens, is closely associated with the cellular membrane compartments, especially the endoplasmic reticulum (ER. Coronavirus infection of cultured cells was previously shown to cause ER stress and induce the unfolded protein response (UPR, a process that aims to restore the ER homeostasis by global translation shutdown and increasing the ER folding capacity. However under prolonged ER stress, UPR can also induce apoptotic cell death. Accumulating evidence from recent studies has shown that induction of ER stress and UPR may constitute a major aspect of coronavirus-host interaction. Activation of the three branches of UPR modulates a wide variety of signaling pathways, such as mitogen-activated protein (MAP kinases activation, autophagy, apoptosis and innate immune response. ER stress and UPR activation may therefore contribute significantly to the viral replication and pathogenesis during coronavirus infection. In this review, we summarize current knowledge on coronavirus-induced ER stress and UPR activation, with emphasis on their cross-talking to apoptotic signaling.

  8. ER Stress: A Therapeutic Target in Rheumatoid Arthritis?

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    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.

  9. ER stress, autophagy, and RNA viruses

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    Jia-Rong eJheng

    2014-08-01

    Full Text Available Endoplasmic reticulum (ER stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR, which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell’s response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host’s defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment.

  10. AAV delivery of GRP78/BiP promotes adaptation of human RPE cell to ER stress.

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    Ghaderi, Shima; Ahmadian, Shahin; Soheili, Zahra-Soheila; Ahmadieh, Hamid; Samiei, Shahram; Kheitan, Samira; Pirmardan, Ehsan R

    2018-02-01

    Adeno associated virus (AAV)-mediated gene delivery of GRP78 (78 kDa glucose-regulated protein) attenuates the condition of endoplasmic reticulum (ER) stress and prevents apoptotic loss of photoreceptors in Retinitis pigmentosa (RP) rats. In the current study we overexpressed Grp78 with the help of AAV-2 in primary human retinal pigmented epithelium (hRPE) cell cultures and examined its effect on cell response to ER stress. The purpose of this work was studying potential stimulating effect of GRP78 on adaptation/pro-survival of hRPE cells under ER stress, as an in vitro model for RPE degeneration. To investigate the effect of Grp78 overexpression on unfolded protein response (UPR) markers under ER stress, hRPE primary cultures were transduced by recombinant virus rAAV/Grp78, and treated with ER stressor drug, tunicamycin. Expression changes of four UPR markers including GRP78, PERK, ATF6α, and GADD153/CHOP, were assessed by real-time PCR and western blotting. We found that GRP78 has a great contribution in modulation of UPR markers to favor adaptive response in ER-stressed hRPE cells. In fact, GRP78 overexpression affected adaptation and apoptotic phases of early UPR, through enhancement of two master regulators/ER stress sensors (PERK and ATF6α) and down-regulation of a key pro-apoptotic cascade activator (GADD153/CHOP). Together these findings demonstrate the promoting effect of GRP78 on adaptation/pro-survival of hRPE cells under ER stress. This protein with anti-apoptotic actions in the early UPR and important role in cell fate regulation, can be recruited as a useful candidate for future investigations of RPE degenerative diseases. © 2017 Wiley Periodicals, Inc.

  11. Mechanisms of ER Stress-Mediated Mitochondrial Membrane Permeabilization.

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    Gupta, Sanjeev

    2010-01-01

    During apoptosis, the process of mitochondrial outer membrane permeabilization (MOMP) represents a point-of-no-return as it commits the cell to death. Here we have assessed the role of caspases, Bcl-2 family members and the mitochondrial permeability transition pore on ER stress-induced MOMP and subsequent cell death. Induction of ER stress leads to upregulation of several genes such as Grp78, Edem1, Erp72, Atf4, Wars, Herp, p58ipk, and ERdj4 and leads to caspase activation, release of mitochondrial intermembrane proteins and dissipation of mitochondrial transmembrane potential (DeltaPsim). Mouse embryonic fibroblasts (MEFs) from caspase-9, -2 and, -3 knock-out mice were resistant to ER stress-induced apoptosis which correlated with decreased processing of pro-caspase-3 and -9. Furthermore, pretreatment of cells with caspase inhibitors (Boc-D.fmk and DEVD.fmk) attenuated ER stress-induced loss of DeltaPsim. However, only deficiency of caspase-9 and -2 could prevent ER stress-mediated loss of DeltaPsim. Bcl-2 overexpression or pretreatment of cells with the cell permeable BH4 domain (BH4-Tat) or the mitochondrial permeability transition pore inhibitors, bongkrekic acid or cyclosporine A, attenuated the ER stress-induced loss of DeltaPsim. These data suggest a role for caspase-9 and -2, Bcl-2 family members and the mitochondrial permeability transition pore in loss of mitochondrial membrane potential during ER stress-induced apoptosis.

  12. Dietary toxins, endoplasmic reticulum (ER) stress and diabetes.

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    Hettiarachchi, Kalindi D; Zimmet, Paul Z; Myers, Mark A

    2008-05-01

    The incidence of Type 1 diabetes has been increasing at a rate too rapid to be due to changes in genetic risk. Instead changes in environmental factors are the likely culprit. The endoplasmic reticulum (ER) plays an important role in the production of newly synthesized proteins and interference with these processes leads to ER stress. The insulin-producing beta cells are particularly prone to ER stress as a result of their heavy engagement in insulin production. Increasing evidence suggests ER stress is central to initiation and progression of Type 1 diabetes. An early environmental exposure, such as toxins and viral infections, can impart a significant physiological load on beta cells to initiate abnormal processing of proinsulin, ER stress and insulin secretory defects. Release of altered proinsulin from the beta cells early in life may trigger autoimmunity in those with genetic susceptibility leading to cytokine-induced nitric oxide production and so exacerbating ER stress in beta cells, ultimately leading to apoptosis of beta cells and diabetes. Here we suggest that ER stress is an inherent cause of beta cell dysfunction and environmental factors, in particular dietary toxins derived from Streptomyces in infected root vegetables, can impart additional stress that aggravates beta cell death and progression to diabetes. Furthermore, we propose that the increasing incidence of Type 1 diabetes may be accounted for by increased dietary exposure to ER-stress-inducing Streptomyces toxins.

  13. Aging induced ER stress alters sleep and sleep homeostasis

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    Brown, Marishka K.; Chan, May T.; Zimmerman, John E.; Pack, Allan I.; Jackson, Nicholas E.; Naidoo, Nirinjini

    2014-01-01

    Alterations in the quality, quantity and architecture of baseline and recovery sleep have been shown to occur during aging. Sleep deprivation induces endoplasmic reticular (ER) stress and upregulates a protective signaling pathway termed the unfolded protein response (UPR). The effectiveness of the adaptive UPR is diminished by age. Previously, we showed that endogenous chaperone levels altered recovery sleep in Drosophila melanogaster. We now report that acute administration of the chemical chaperone sodium 4-phenylbutyrate (PBA) reduces ER stress and ameliorates age-associated sleep changes in Drosophila. PBA consolidates both baseline and recovery sleep in aging flies. The behavioral modifications of PBA are linked to its suppression of ER stress. PBA decreased splicing of x-box binding protein 1 (XBP1) and upregulation of phosphorylated elongation initiation factor 2 α (p-eIF2α), in flies that were subjected to sleep deprivation. We also demonstrate that directly activating ER stress in young flies fragments baseline sleep and alters recovery sleep. Alleviating prolonged/sustained ER stress during aging contributes to sleep consolidation and improves recovery sleep/ sleep debt discharge. PMID:24444805

  14. Induction of ER stress in macrophages of tuberculosis granulomas.

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    Tracie A Seimon

    2010-09-01

    Full Text Available The endoplasmic reticulum (ER stress pathway known as the Unfolded Protein Response (UPR is an adaptive survival pathway that protects cells from the buildup of misfolded proteins, but under certain circumstances it can lead to apoptosis. ER stress has been causally associated with macrophage apoptosis in advanced atherosclerosis of mice and humans. Because atherosclerosis shares certain features with tuberculosis (TB with regard to lesional macrophage accumulation, foam cell formation, and apoptosis, we investigated if the ER stress pathway is activated during TB infection.Here we show that ER stress markers such as C/EBP homologous protein (CHOP; also known as GADD153, phosphorylated inositol-requiring enzyme 1 alpha (Ire1α and eukaryotic initiation factor 2 alpha (eIF2α, and activating transcription factor 3 (ATF3 are expressed in macrophage-rich areas of granulomas in lungs of mice infected with virulent Mycobacterium tuberculosis (Mtb. These areas were also positive for numerous apoptotic cells as assayed by TUNEL. Microarray analysis of human caseous TB granulomas isolated by laser capture microdissection reveal that 73% of genes involved in the UPR are upregulated at the mRNA transcript level. The expression of two ER stress markers, ATF3 and CHOP, were also increased in macrophages of human TB granulomas when assayed by immunohistochemistry. CHOP has been causally associated with ER stress-induced macrophage apoptosis. We found that apoptosis was more abundant in granulomas as compared to non-granulomatous tissue isolated from patients with pulmonary TB, and apoptosis correlated with CHOP expression in areas surrounding the centralized areas of caseation.In summary, ER stress is induced in macrophages of TB granulomas in areas where apoptotic cells accumulate in mice and humans. Although macrophage apoptosis is generally thought to be beneficial in initially protecting the host from Mtb infection, death of infected macrophages in

  15. Rab7a modulates ER stress and ER morphology.

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    Mateus, Duarte; Marini, Elettra Sara; Progida, Cinzia; Bakke, Oddmund

    2018-05-01

    The Endoplasmic Reticulum (ER) is a membranous organelle with diverse structural and functional domains. Peripheral ER includes interconnected tubules, and dense tubular arrays called "ER matrices" together with bona fide flat cisternae. Transitions between these states are regulated by membrane-associated proteins and cytosolic factors. Recently, the small GTPases Rab10 and Rab18 were reported to control ER shape by regulating ER dynamics and fusion. Here, we present evidence that another Rab protein, Rab7a, modulates the ER morphology by controlling the ER homeostasis and ER stress. Indeed, inhibition of Rab7a expression by siRNA or expression of the dominant negative mutant Rab7aT22 N, leads to enlargement of sheet-like ER structures and spreading towards the cell periphery. Notably, such alterations are ascribable neither to a direct modulation of the ER shaping proteins Reticulon-4b and CLIMP63, nor to interactions with Protrudin, a Rab7a-binding protein known to affect the ER organization. Conversely, depletion of Rab7a leads to basal ER stress, in turn causing ER membrane expansion. Both ER enlargement and basal ER stress are reverted in rescue experiments by Rab7a re-expression, as well as by the ER chemical chaperone tauroursodeoxycholic acid (TUDCA). Collectively, these findings reveal a new role of Rab7a in ER homeostasis, and indicate that genetic and pharmacological ER stress manipulation may restore ER morphology in Rab7a silenced cells. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Aging induced ER stress alters sleep and sleep homeostasis

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    Brown, Marishka K.; Chan, May T.; Zimmerman, John E.; Pack, Allan I.; Jackson, Nicholas E.; Naidoo, Nirinjini

    2013-01-01

    Alterations in the quality, quantity and architecture of baseline and recovery sleep have been shown to occur during aging. Sleep deprivation induces endoplasmic reticular (ER) stress and upregulates a protective signaling pathway termed the unfolded protein response (UPR). The effectiveness of the adaptive UPR is diminished by age. Previously, we showed that endogenous chaperone levels altered recovery sleep in Drosophila melanogaster. We now report that acute administration of the chemical ...

  17. ER stress proteins in autoimmune and inflammatory diseases

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    Daisuke eMorito

    2012-03-01

    Full Text Available Over the past two decades, heat shock proteins (HSPs have been implicated in inflammatory responses and autoimmunity. HSPs were originally believed to maintain protein quality control in the cytosol. However, they also exist extracellularly and appear to act as inflammatory factors. Recently, a growing body of evidence suggested that the other class of stress proteins such as, endoplasmic reticulum (ER stress proteins, which originally act as protein quality control factors in the secretory pathway and are induced by ER stress in inflammatory lesions, also participate in inflammation and autoimmunity. The immunoglobulin heavy-chain binding protein (Bip/glucose-regulated protein 78 (Grp78, homocysteine-induced ER protein (Herp, calnexin, calreticulin, glucose-regulated protein 94 (Grp94/gp96, oxygen-regulated protein 150 (ORP150 and heat shock protein 47 (Hsp47/Serpin H1, which are expressed not only in the ER but also occasionally at the cell surface play pathophysiological roles in autoimmune and inflammatory diseases as pro- or anti-inflammatory factors. Here we describe the accumulating evidence of the participation of ER stress proteins in autoimmunity and inflammation and discuss the critical differences between the two classes of stress proteins.

  18. Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy

    International Nuclear Information System (INIS)

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng

    2015-01-01

    Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressive ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy. - Highlights: • Oroxin B selectively induces tumor-suppressive ER stress in B-lymphoma cells. • Oroxin B significantly prolonged overall survival of lymphoma-xenografted mice.

  19. Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng, E-mail: zhouqs@suda.edu.cn

    2015-10-15

    Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressive ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy. - Highlights: • Oroxin B selectively induces tumor-suppressive ER stress in B-lymphoma cells. • Oroxin B significantly prolonged overall survival of lymphoma-xenografted mice.

  20. ER Stress and β-Cell Pathogenesis of Type 1 and Type 2 Diabetes and Islet Transplantation

    OpenAIRE

    Kataoka, Hitomi Usui; Noguchi, Hirofumi

    2013-01-01

    Endoplasmic reticulum (ER) stress affects the pathogenesis of diabetes. ER stress plays important roles, both in type 1 and type 2 diabetes, because pancreatic β-cells possess highly developed ER for insulin secretion. This review summarizes the relationship between ER stress and the pathogenesis of type 1 and type 2 diabetes. In addition, the association between islet transplantation and ER stress is discussed.

  1. ER stress-induced protein, VIGG, disturbs plant cation homeostasis, which is correlated with growth retardation and robustness to ER stress

    International Nuclear Information System (INIS)

    Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki; Ogawa, Atsushi; Suzuki, Shunji

    2011-01-01

    Highlights: → VIGG is an ER stress-induced protein in plant. → We examine the characteristics of VIGG-overexpressing Arabidopsis plants. → VIGG-overexpressing plants reveal growth retardation and robustness to ER stress. → VIGG disturbs cation homeostasis in plant. -- Abstract: VIGG is a putative endoplasmic reticulum (ER) resident protein induced by virus infection and ER stress, and is correlated with fruit quality in grapevine. The present study was undertaken to determine the biological function of VIGG in grapevine. Experiments using fluorescent protein-VIGG fusion protein demonstrated that VIGG is localized in ER and the ER targeting sequence is in the N-terminus. The overexpression of VIGG in Arabidopsis plant led to growth retardation. The rosette leaves of VIGG-overexpressing plants were smaller than those of the control plants and rolled at 42 days after seeding. VIGG-overexpressing plants revealed robustness to ER stress as well as the low expression of ER stress marker proteins, such as the luminal binding proteins. These characteristics of VIGG-overexpressing plants were supported by a microarray experiment that demonstrated the disruption of genes related to ER stress response and flowering, as well as cation mobility, in the plants. Finally, cation homeostasis in the plants was disturbed by the overexpression of VIGG. Taken together, these results suggest that VIGG may disturb cation homeostasis in plant, which is correlated with the robustness to ER stress and growth retardation.

  2. ER stress-induced protein, VIGG, disturbs plant cation homeostasis, which is correlated with growth retardation and robustness to ER stress

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki [Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005 (Japan); Ogawa, Atsushi [Department of Biological Production, Akita Prefectural University, Shimosinjyou-nakano 241-438, Akita 010-0195 (Japan); Suzuki, Shunji, E-mail: suzukis@yamanashi.ac.jp [Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005 (Japan)

    2011-02-18

    Highlights: {yields} VIGG is an ER stress-induced protein in plant. {yields} We examine the characteristics of VIGG-overexpressing Arabidopsis plants. {yields} VIGG-overexpressing plants reveal growth retardation and robustness to ER stress. {yields} VIGG disturbs cation homeostasis in plant. -- Abstract: VIGG is a putative endoplasmic reticulum (ER) resident protein induced by virus infection and ER stress, and is correlated with fruit quality in grapevine. The present study was undertaken to determine the biological function of VIGG in grapevine. Experiments using fluorescent protein-VIGG fusion protein demonstrated that VIGG is localized in ER and the ER targeting sequence is in the N-terminus. The overexpression of VIGG in Arabidopsis plant led to growth retardation. The rosette leaves of VIGG-overexpressing plants were smaller than those of the control plants and rolled at 42 days after seeding. VIGG-overexpressing plants revealed robustness to ER stress as well as the low expression of ER stress marker proteins, such as the luminal binding proteins. These characteristics of VIGG-overexpressing plants were supported by a microarray experiment that demonstrated the disruption of genes related to ER stress response and flowering, as well as cation mobility, in the plants. Finally, cation homeostasis in the plants was disturbed by the overexpression of VIGG. Taken together, these results suggest that VIGG may disturb cation homeostasis in plant, which is correlated with the robustness to ER stress and growth retardation.

  3. Pharmacologic inhibition of S1P attenuates ATF6 expression, causes ER stress and contributes to apoptotic cell death.

    Science.gov (United States)

    Lebeau, Paul; Byun, Jae Hyun; Yousof, Tamana; Austin, Richard C

    2018-04-22

    Mammalian cells express unique transcription factors embedded in the endoplasmic reticulum (ER) membrane, such as the sterol regulatory element-binding proteins (SREBPs), that promote de novo lipogenesis. Upon their release from the ER, the SREBPs require proteolytic activation in the Golgi by site-1-protease (S1P). As such, inhibition of S1P, using compounds such as PF-429242 (PF), reduces cholesterol synthesis and may represent a new strategy for the management of dyslipidemia. In addition to the SREBPs, the unfolded protein response (UPR) transducer, known as the activating transcription factor 6 (ATF6), is another ER membrane-bound transcription factor that requires S1P-mediated activation. ATF6 regulates ER protein folding capacity by promoting the expression of ER chaperones such as the 78-kDa glucose-regulated protein (GRP78). ER-resident chaperones like GRP78 prevent and/or resolve ER polypeptide accumulation and subsequent ER stress-induced UPR activation by folding nascent polypeptides. Here we report that pharmacological inhibition of S1P reduced the expression of ATF6 and GRP78 and induced the activation of UPR transducers inositol-requiring enzyme-1α (IRE1α) and protein kinase RNA-like ER kinase (PERK). As a consequence, S1P inhibition also increased the susceptibility of cells to ER stress-induced cell death. Our findings suggest that S1P plays a crucial role in the regulation of ER folding capacity and also identifies a compensatory cross-talk between UPR transducers in order to maintain adequate ER chaperone expression and activity. Copyright © 2018. Published by Elsevier Inc.

  4. Overexpressed cyclophilin B suppresses apoptosis associated with ROS and Ca2+ homeostasis after ER stress.

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    Kim, Jinhwan; Choi, Tae Gyu; Ding, Yan; Kim, Yeonghwan; Ha, Kwon Soo; Lee, Kyung Ho; Kang, Insug; Ha, Joohun; Kaufman, Randal J; Lee, Jinhwa; Choe, Wonchae; Kim, Sung Soo

    2008-11-01

    Prolonged accumulation of misfolded proteins in the endoplasmic reticulum (ER) results in ER stress-mediated apoptosis. Cyclophilins are protein chaperones that accelerate the rate of protein folding through their peptidyl-prolyl cis-trans isomerase (PPIase) activity. In this study, we demonstrated that ER stress activates the expression of the ER-localized cyclophilin B (CypB) gene through a novel ER stress response element. Overexpression of wild-type CypB attenuated ER stress-induced cell death, whereas overexpression of an isomerase activity-defective mutant, CypB/R62A, not only increased Ca(2+) leakage from the ER and ROS generation, but also decreased mitochondrial membrane potential, resulting in cell death following exposure to ER stress-inducing agents. siRNA-mediated inhibition of CypB expression rendered cells more vulnerable to ER stress. Finally, CypB interacted with the ER stress-related chaperones, Bip and Grp94. Taken together, we concluded that CypB performs a crucial function in protecting cells against ER stress via its PPIase activity.

  5. Wolfram syndrome 1 gene negatively regulates ER stress signaling in rodent and human cells.

    Science.gov (United States)

    Fonseca, Sonya G; Ishigaki, Shinsuke; Oslowski, Christine M; Lu, Simin; Lipson, Kathryn L; Ghosh, Rajarshi; Hayashi, Emiko; Ishihara, Hisamitsu; Oka, Yoshitomo; Permutt, M Alan; Urano, Fumihiko

    2010-03-01

    Wolfram syndrome is an autosomal-recessive disorder characterized by insulin-dependent diabetes mellitus, caused by nonautoimmune loss of beta cells, and neurological dysfunctions. We have previously shown that mutations in the Wolfram syndrome 1 (WFS1) gene cause Wolfram syndrome and that WFS1 has a protective function against ER stress. However, it remained to be determined how WFS1 mitigates ER stress. Here we have shown in rodent and human cell lines that WFS1 negatively regulates a key transcription factor involved in ER stress signaling, activating transcription factor 6alpha (ATF6alpha), through the ubiquitin-proteasome pathway. WFS1 suppressed expression of ATF6alpha target genes and repressed ATF6alpha-mediated activation of the ER stress response element (ERSE) promoter. Moreover, WFS1 stabilized the E3 ubiquitin ligase HRD1, brought ATF6alpha to the proteasome, and enhanced its ubiquitination and proteasome-mediated degradation, leading to suppression of ER stress signaling. Consistent with these data, beta cells from WFS1-deficient mice and lymphocytes from patients with Wolfram syndrome exhibited dysregulated ER stress signaling through upregulation of ATF6alpha and downregulation of HRD1. These results reveal a role for WFS1 in the negative regulation of ER stress signaling and in the pathogenesis of diseases involving chronic, unresolvable ER stress, such as pancreatic beta cell death in diabetes.

  6. Reduced α-MSH Underlies Hypothalamic ER-Stress-Induced Hepatic Gluconeogenesis.

    Science.gov (United States)

    Schneeberger, Marc; Gómez-Valadés, Alicia G; Altirriba, Jordi; Sebastián, David; Ramírez, Sara; Garcia, Ainhoa; Esteban, Yaiza; Drougard, Anne; Ferrés-Coy, Albert; Bortolozzi, Analía; Garcia-Roves, Pablo M; Jones, John G; Manadas, Bruno; Zorzano, Antonio; Gomis, Ramon; Claret, Marc

    2015-07-21

    Alterations in ER homeostasis have been implicated in the pathophysiology of obesity and type-2 diabetes (T2D). Acute ER stress induction in the hypothalamus produces glucose metabolism perturbations. However, the neurobiological basis linking hypothalamic ER stress with abnormal glucose metabolism remains unknown. Here, we report that genetic and induced models of hypothalamic ER stress are associated with alterations in systemic glucose homeostasis due to increased gluconeogenesis (GNG) independent of body weight changes. Defective alpha melanocyte-stimulating hormone (α-MSH) production underlies this metabolic phenotype, as pharmacological strategies aimed at rescuing hypothalamic α-MSH content reversed this phenotype at metabolic and molecular level. Collectively, our results posit defective α-MSH processing as a fundamental mediator of enhanced GNG in the context of hypothalamic ER stress and establish α-MSH deficiency in proopiomelanocortin (POMC) neurons as a potential contributor to the pathophysiology of T2D. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  7. ZmbZIP60 mRNA is spliced in maize in response to ER stress

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    Li Yanjie

    2012-03-01

    Full Text Available Abstract Background Adverse environmental conditions produce ER stress and elicit the unfolded protein response (UPR in plants. Plants are reported to have two "arms" of the ER stress signaling pathway-one arm involving membrane-bound transcription factors and the other involving a membrane-associated RNA splicing factor, IRE1. IRE1 in yeast to mammals recognizes a conserved twin loop structure in the target RNA. Results A segment of the mRNA encoding ZmbZIP60 in maize can be folded into a twin loop structure, and in response to ER stress this mRNA is spliced, excising a 20b intron. Splicing converts the predicted protein from a membrane-associated transcription factor to one that is targeted to the nucleus. Splicing of ZmbZIP60 can be elicited in maize seedlings by ER stress agents such as dithiothreitol (DTT or tunicamycin (TM or by heat treatment. Younger, rather than older seedlings display a more robust splicing response as do younger parts of leaf, along a developmental gradient in a leaf. The molecular signature of an ER stress response in plants includes the upregulation of Binding Protein (BIP genes. Maize has numerous BIP-like genes, and ER stress was found to upregulate one of these, ZmBIPb. Conclusions The splicing of ZmbZIP60 mRNA is an indicator of ER stress in maize seedlings resulting from adverse environmental conditions such as heat stress. ZmbZIP60 mRNA splicing in maize leads predictively to the formation of active bZIP transcription factor targeted to the nucleus to upregulate stress response genes. Among the genes upregulated by ER stress in maize is one of 22 BIP-like genes, ZmBIPb.

  8. SIRT7 Represses Myc Activity to Suppress ER Stress and Prevent Fatty Liver Disease

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    Jiyung Shin

    2013-11-01

    Full Text Available Nonalcoholic fatty liver disease is the most common chronic liver disorder in developed countries. Its pathogenesis is poorly understood, and therapeutic options are limited. Here, we show that SIRT7, an NAD+-dependent H3K18Ac deacetylase, functions at chromatin to suppress ER stress and prevent the development of fatty liver disease. SIRT7 is induced upon ER stress and is stabilized at the promoters of ribosomal proteins through its interaction with the transcription factor Myc to silence gene expression and to relieve ER stress. SIRT7-deficient mice develop chronic hepatosteatosis resembling human fatty liver disease. Myc inactivation or pharmacological suppression of ER stress alleviates fatty liver caused by SIRT7 deficiency. Importantly, SIRT7 suppresses ER stress and reverts the fatty liver disease in diet-induced obese mice. Our study identifies SIRT7 as a cofactor of Myc for transcriptional repression and delineates a druggable regulatory branch of the ER stress response that prevents and reverts fatty liver disease.

  9. Lycopene Protects against Hypoxia/Reoxygenation Injury by Alleviating ER Stress Induced Apoptosis in Neonatal Mouse Cardiomyocytes

    Science.gov (United States)

    Xu, Jiqian; Hu, Houxiang; Chen, Bin; Yue, Rongchuan; Zhou, Zhou; Liu, Yin; Zhang, Shuang; Xu, Lei; Wang, Huan; Yu, Zhengping

    2015-01-01

    Endoplasmic reticulum (ER) stress induced apoptosis plays a pivotal role in myocardial ischemia/reperfusion (I/R)-injury. Inhibiting ER stress is a major therapeutic target/strategy in treating cardiovascular diseases. Our previous studies revealed that lycopene exhibits great pharmacological potential in protecting against the I/R-injury in vitro and vivo, but whether attenuation of ER stress (and) or ER stress-induced apoptosis contributes to the effects remains unclear. In the present study, using neonatal mouse cardiomyocytes to establish an in vitro model of hypoxia/reoxygenation (H/R) to mimic myocardium I/R in vivo, we aimed to explore the hypothesis that lycopene could alleviate the ER stress and ER stress-induced apoptosis in H/R-injury. We observed that lycopene alleviated the H/R injury as revealed by improving cell viability and reducing apoptosis, suppressed reactive oxygen species (ROS) generation and improved the phosphorylated AMPK expression, attenuated ER stress as evidenced by decreasing the expression of GRP78, ATF6 mRNA, sXbp-1 mRNA, eIF2α mRNA and eIF2α phosphorylation, alleviated ER stress-induced apoptosis as manifested by reducing CHOP/GADD153 expression, the ratio of Bax/Bcl-2, caspase-12 and caspase-3 activity in H/R-treated cardiomyocytes. Thapsigargin (TG) is a potent ER stress inducer and used to elicit ER stress of cardiomyocytes. Our results showed that lycopene was able to prevent TG-induced ER stress as reflected by attenuating the protein expression of GRP78 and CHOP/GADD153 compared to TG group, significantly improve TG-caused a loss of cell viability and decrease apoptosis in TG-treated cardiomyocytes. These results suggest that the protective effects of lycopene on H/R-injury are, at least in part, through alleviating ER stress and ER stress-induced apoptosis in neonatal mouse cardiomyocytes. PMID:26291709

  10. Endoplasmic reticulum (ER) stress and cAMP/PKA pathway mediated Zn-induced hepatic lipolysis.

    Science.gov (United States)

    Song, Yu-Feng; Hogstrand, Christer; Wei, Chuan-Chuan; Wu, Kun; Pan, Ya-Xiong; Luo, Zhi

    2017-09-01

    The present study was performed to determine the effect of Zn exposure influencing endoplasmic reticulum (ER) stress, explore the underlying molecular mechanism of Zn-induced hepatic lipolysis in a fish species of significance for aquaculture, yellow catfish Pelteobagrus fulvidraco. We found that waterborne Zn exposure evoked ER stress and unfolded protein response (UPR), and activated cAMP/PKA pathway, and up-regulated hepatic lipolysis. The increase in ER stress and lipolysis were associated with activation of cAMP/PKA signaling pathway. Zn also induced an increase in intracellular Ca 2+ level, which could be partially prevented by dantrolene (RyR receptor inhibitor) and 2-APB (IP3 receptor inhibitor), demonstrating that the disturbed Ca 2+ homeostasis in ER contributed to ER stress and dysregulation of lipolysis. Inhibition of ER stress by PBA attenuated UPR, inhibited the activation of cAMP/PKA pathway and resulted in down-regulation of lipolysis. Inhibition of protein kinase RNA-activated-like ER kinase (PERK) by GSK2656157 and inositol-requiring enzyme (IRE) by STF-083010 differentially influenced Zn-induced changes of lipid metabolism, indicating that PERK and IRE pathways played different regulatory roles in Zn-induced lipolysis. Inhibition of PKA by H89 blocked the Zn-induced activation of cAMP/PKA pathway with a concomitant inhibition of ER stress-mediated lipolysis. Taken together, our findings highlight the importance of the ER stress-cAMP/PKA axis in Zn-induced lipolysis, which provides new insights into Zn toxicology in fish and probably in other vertebrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Transcription regulator TRIP-Br2 mediates ER stress-induced brown adipocytes dysfunction.

    Science.gov (United States)

    Qiang, Guifen; Whang Kong, Hyerim; Gil, Victoria; Liew, Chong Wee

    2017-01-09

    In contrast to white adipose tissue, brown adipose tissue (BAT) is known to play critical roles for both basal and inducible energy expenditure. Obesity is associated with reduction of BAT function; however, it is not well understood how obesity promotes BAT dysfunction, especially at the molecular level. Here we show that the transcription regulator TRIP-Br2 mediates ER stress-induced inhibition of lipolysis and thermogenesis in BAT. Using in vitro, ex vivo, and in vivo approaches, we demonstrate that obesity-induced inflammation upregulates brown adipocytes TRIP-Br2 expression via the ER stress pathway and amelioration of ER stress in mice completely abolishes high fat diet-induced upregulation of TRIP-Br2 in BAT. We find that increased TRIP-Br2 significantly inhibits brown adipocytes thermogenesis. Finally, we show that ablation of TRIP-Br2 ameliorates ER stress-induced inhibition on lipolysis, fatty acid oxidation, oxidative metabolism, and thermogenesis in brown adipocytes. Taken together, our current study demonstrates a role for TRIP-Br2 in ER stress-induced BAT dysfunction, and inhibiting TRIP-Br2 could be a potential approach for counteracting obesity-induced BAT dysfunction.

  12. ER stress is the initial response to polyglutamine toxicity in PC12 cells

    International Nuclear Information System (INIS)

    Nakayama, Hitoshi; Hamada, Masashi; Fujikake, Nobuhiro; Nagai, Yoshitaka; Zhao, Jing; Hatano, Osamu; Shimoke, Koji; Isosaki, Minoru; Yoshizumi, Masanori; Ikeuchi, Toshihiko

    2008-01-01

    Persistent endoplasmic reticulum (ER) stress and impairment of the ubiquitin-proteasome system (UPS) cause neuronal cell death. However, the relationship between these two phenomena remains controversial. In our current study, we have utilized an expanded polyglutamine fusion protein (polyQ81) expression system in PC12 cells to further examine the involvement of ER stress and UPS impairment in cell death. The expression of polyQ81-induced ER stress and cell death. PolyQ81 also induced the activation of c-Jun N-terminal kinase (JNK) and caspase-3 and an increase in polyubiquitin immunoreactivity, suggesting UPS impairment. ER stress was induced prior to the accumulation of polyubiquitinated proteins. Low doses of lactacystin had almost similar effects on cell viability and on the activation of JNK and caspase-3 between normal cells and polyQ81-expressing cells. These results suggest that ER stress mediates polyglutamine toxicity prior to UPS impairment during the initial stages of these toxic effects.

  13. Acute Lung Injury Results from Innate Sensing of Viruses by an ER Stress Pathway

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    Eike R. Hrincius

    2015-06-01

    Full Text Available Incursions of new pathogenic viruses into humans from animal reservoirs are occurring with alarming frequency. The molecular underpinnings of immune recognition, host responses, and pathogenesis in this setting are poorly understood. We studied pandemic influenza viruses to determine the mechanism by which increasing glycosylation during evolution of surface proteins facilitates diminished pathogenicity in adapted viruses. ER stress during infection with poorly glycosylated pandemic strains activated the unfolded protein response, leading to inflammation, acute lung injury, and mortality. Seasonal strains or viruses engineered to mimic adapted viruses displaying excess glycans on the hemagglutinin did not cause ER stress, allowing preservation of the lungs and survival. We propose that ER stress resulting from recognition of non-adapted viruses is utilized to discriminate “non-self” at the level of protein processing and to activate immune responses, with unintended consequences on pathogenesis. Understanding this mechanism should improve strategies for treating acute lung injury from zoonotic viral infections.

  14. Cocaine induces astrocytosis through ER stress-mediated activation of autophagy

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    Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

    2016-01-01

    ABSTRACT Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation. PMID:27337297

  15. New insights on the functional role of URG7 in the cellular response to ER stress.

    Science.gov (United States)

    Armentano, Maria Francesca; Caterino, Marianna; Miglionico, Rocchina; Ostuni, Angela; Pace, Maria Carmela; Cozzolino, Flora; Monti, Maria; Milella, Luigi; Carmosino, Monica; Pucci, Piero; Bisaccia, Faustino

    2018-04-28

    Up-regulated Gene clone 7 (URG7) is an ER resident protein, whose expression is up-regulated in the presence of hepatitis B virus X antigen (HBxAg) during HBV infection. In virus-infected hepatocytes, URG7 shows an anti-apoptotic activity due to the PI3K/AKT signalling activation, does not seem to have tumorigenic properties, but it appears to promote the development and progression of fibrosis. However, the molecular mechanisms underlying URG7 activity remain largely unknown. To shed light on URG7 activity, we first analysed its interactome in HepG2 transfected cells: this analysis suggests that URG7 could have a role in affecting protein synthesis, folding and promoting proteins degradation. Moreover, keeping into account its subcellular localisation in the ER and that several viral infections give rise to ER stress, a panel of experiments was performed to evaluate a putative role of URG7 in ER stress. Our main results demonstrate that in ER-stressed cells URG7 is able to modulate the expression of Unfolded Protein Response (UPR) markers towards survival outcomes, up-regulating GRP78 protein and down-regulating the pro-apoptotic protein CHOP. Furthermore, URG7 reduces the ER stress by decreasing the amount of unfolded proteins, by increasing both the total protein ubiquitination and the AKT activation and reducing Caspase 3 activation. All together these data suggest that URG7 plays a pivotal role as a reliever of ER stress-induced apoptosis. This is the first characterisation of URG7 activity under ER stress conditions. The results presented here will help to hypothesise new strategies to counteract the antiapoptotic activity of URG7 in the context of the viral infection. © 2018 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  16. ER stress affects processing of MHC class I-associated peptides

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    Meloche Sylvain

    2009-02-01

    Full Text Available Abstract Background Viral infection and neoplastic transformation trigger endoplasmic reticulum (ER stress. Thus, a large proportion of the cells that must be recognized by the immune system are stressed cells. Cells respond to ER stress by launching the unfolded protein response (UPR. The UPR regulates the two key processes that control major histocompatibility complex class I (MHC I-peptide presentation: protein synthesis and degradation. We therefore asked whether and how the UPR impinges on MHC I-peptide presentation. Results We evaluated the impact of the UPR on global MHC I expression and on presentation of the H2Kb-associated SIINFEKL peptide. EL4 cells stably transfected with vectors coding hen egg lysozyme (HEL-SIINFEKL protein variants were stressed with palmitate or exposed to glucose deprivation. UPR decreased surface expression of MHC I but did not affect MHC I mRNA level nor the total amount of intracellular MHC I proteins. Impaired MHC I-peptide presentation was due mainly to reduced supply of peptides owing to an inhibition of overall protein synthesis. Consequently, generation of H2Kb-SIINFEKL complexes was curtailed during ER stress, illustrating how generation of MHC I peptide ligands is tightly coupled to ongoing protein synthesis. Notably, the UPR-induced decline of MHC I-peptide presentation was more severe when the protein source of peptides was localized in the cytosol than in the ER. This difference was not due to changes in the translation rates of the precursor proteins but to increased stability of the cytosolic protein during ER stress. Conclusion Our results demonstrate that ER stress impairs MHC I-peptide presentation, and that it differentially regulates expression of ER- vs. cytosol-derived peptides. Furthermore, this work illustrates how ER stress, a typical feature of infected and malignant cells, can impinge on cues for adaptive immune recognition.

  17. Altered methylation and expression of ER-associated degradation factors in long-term alcohol and constitutive ER stress-induced murine hepatic tumors

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    Hui eHan

    2013-10-01

    Full Text Available Mortality from liver cancer in humans is increasingly attributable to heavy or long-term alcohol consumption. The mechanisms by which alcohol exerts its carcinogenic effect are not well understood. In this study, the role of alcohol-induced endoplasmic reticulum (ER stress response in liver cancer development was investigated using an animal model with a liver knockout of the chaperone BiP and under constitutive hepatic ER stress. Long-term alcohol and high fat diet (HFD feeding resulted in higher levels of serum alanine aminotransferase (ALT, impaired ER stress response, and higher incidence of liver tumor in older (aged 16 months knockout females than in either middle-aged (6 months knockouts or older (aged 16 months wild type females. In the older knockout females, stronger effects of the alcohol on methylation of CpG islands at promoter regions of genes involved in the ER associated degradation (ERAD were also detected. Altered expression of ERAD factors including derlin 3, Creld2 (cysteine-rich with EGF-like domains 2, Herpud1 (ubiquitin-like domain member, Wfs1 (wolfram syndrome gene, and Yod1 (deubiquinating enzyme 1 was co-present with decreased proteasome activities, increased estrogen receptor alpha variant (ERa36, and enhanced phosphorylations of ERK1/2 (extracellular signal-regulated protein kinases 1 and 2 and STAT3 (the signal transducers and activators of transcription in the older knockout female fed alcohol. Our results suggest that long-term alcohol consumption and ageing may promote liver tumorigenesis in females through interfering with DNA methylation and expression of genes involved in the ER associated degradation.

  18. Acid-induced autophagy protects human lung cancer cells from apoptosis by activating ER stress.

    Science.gov (United States)

    Xie, Wen-Yue; Zhou, Xiang-Dong; Li, Qi; Chen, Ling-Xiu; Ran, Dan-Hua

    2015-12-10

    An acidic tumor microenvironment exists widely in solid tumors. However, the detailed mechanism of cell survival under acidic stress remains unclear. The aim of this study is to clarify whether acid-induced autophagy exists and to determine the function and mechanism of autophagy in lung cancer cells. We have found that acute low pH stimulated autophagy by increasing LC3-positive punctate vesicles, increasing LC3 II expression levels and reducing p62 protein levels. Additionally, autophagy was inhibited by the addition of Baf or knockdown of Beclin 1, and cell apoptosis was increased markedly. In mouse tumors, the expression of cleaved caspase3 and p62 was enhanced by oral treatment with sodium bicarbonate, which can raise the intratumoral pH. Furthermore, the protein levels of ER stress markers, including p-PERK, p-eIF2α, CHOP, XBP-1s and GRP78, were also increased in response to acidic pH. The antioxidant NAC, which reduces ROS accumulation, alleviated acid-mediated ER stress and autophagy, and knocking down GRP78 reduced autophagy activation under acidic conditions, which suggests that autophagy was induced by acidic pH through ER stress. Taken together, these results indicate that the acidic microenvironment in non-small cell lung cancer cells promotes autophagy by increasing ROS-ER stress, which serves as a survival adaption in this setting. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Increased intracellular proteolysis reduces disease severity in an ER stress-associated dwarfism.

    Science.gov (United States)

    Mullan, Lorna A; Mularczyk, Ewa J; Kung, Louise H; Forouhan, Mitra; Wragg, Jordan Ma; Goodacre, Royston; Bateman, John F; Swanton, Eileithyia; Briggs, Michael D; Boot-Handford, Raymond P

    2017-10-02

    The short-limbed dwarfism metaphyseal chondrodysplasia type Schmid (MCDS) is linked to mutations in type X collagen, which increase ER stress by inducing misfolding of the mutant protein and subsequently disrupting hypertrophic chondrocyte differentiation. Here, we show that carbamazepine (CBZ), an autophagy-stimulating drug that is clinically approved for the treatment of seizures and bipolar disease, reduced the ER stress induced by 4 different MCDS-causing mutant forms of collagen X in human cell culture. Depending on the nature of the mutation, CBZ application stimulated proteolysis of misfolded collagen X by either autophagy or proteasomal degradation, thereby reducing intracellular accumulation of mutant collagen. In MCDS mice expressing the Col10a1.pN617K mutation, CBZ reduced the MCDS-associated expansion of the growth plate hypertrophic zone, attenuated enhanced expression of ER stress markers such as Bip and Atf4, increased bone growth, and reduced skeletal dysplasia. CBZ produced these beneficial effects by reducing the MCDS-associated abnormalities in hypertrophic chondrocyte differentiation. Stimulation of intracellular proteolysis using CBZ treatment may therefore be a clinically viable way of treating the ER stress-associated dwarfism MCDS.

  20. The ER stress inducer DMC enhances TRAIL-induced apoptosis in glioblastoma

    NARCIS (Netherlands)

    van Roosmalen, Ingrid A. M.; Dos Reis, Carlos R; Setroikromo, Rita; Yuvaraj, Saravanan; Joseph, Justin V.; Tepper, Pieter G.; Kruyt, Frank A. E.; Quax, Wim J.

    2014-01-01

    Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumour in humans and is highly resistant to current treatment modalities. We have explored the combined treatment of the endoplasmic reticulum (ER) stress-inducing agent 2,5-dimethyl-celecoxib (DMC) and TNF-related

  1. Mitofusin 2 in POMC neurons connects ER stress with leptin resistance and energy imbalance

    DEFF Research Database (Denmark)

    Schneeberger, Marc; Dietrich, Marcelo O; Sebastián, David

    2013-01-01

    Mitofusin 2 (MFN2) plays critical roles in both mitochondrial fusion and the establishment of mitochondria-endoplasmic reticulum (ER) interactions. Hypothalamic ER stress has emerged as a causative factor for the development of leptin resistance, but the underlying mechanisms are largely unknown....

  2. Inflammation and ER Stress Downregulate BDH2 Expression and Dysregulate Intracellular Iron in Macrophages

    Directory of Open Access Journals (Sweden)

    Susu M. Zughaier

    2014-01-01

    Full Text Available Macrophages play a very important role in host defense and in iron homeostasis by engulfing senescent red blood cells and recycling iron. Hepcidin is the master iron regulating hormone that limits dietary iron absorption from the gut and limits iron egress from macrophages. Upon infection macrophages retain iron to limit its bioavailability which limits bacterial growth. Recently, a short chain butyrate dehydrogenase type 2 (BDH2 protein was reported to contain an iron responsive element and to mediate cellular iron trafficking by catalyzing the synthesis of the mammalian siderophore that binds labile iron; therefore, BDH2 plays a crucial role in intracellular iron homeostasis. However, BDH2 expression and regulation in macrophages have not yet been described. Here we show that LPS-induced inflammation combined with ER stress led to massive BDH2 downregulation, increased the expression of ER stress markers, upregulated hepcidin expression, downregulated ferroportin expression, caused iron retention in macrophages, and dysregulated cytokine release from macrophages. We also show that ER stress combined with inflammation synergistically upregulated the expression of the iron carrier protein NGAL and the stress-inducible heme degrading enzyme heme oxygenase-1 (HO-1 leading to iron liberation. This is the first report to show that inflammation and ER stress downregulate the expression of BDH2 in human THP-1 macrophages.

  3. Shikonin ameliorates isoproterenol (ISO)-induced myocardial damage through suppressing fibrosis, inflammation, apoptosis and ER stress.

    Science.gov (United States)

    Yang, Jun; Wang, Zhao; Chen, Dong-Lin

    2017-09-01

    Shikonin, isolated from the roots of herbal plant Lithospermum erythrorhizon, is a naphthoquinone. It has been reported to exert beneficial anti-inflammatory effects and anti-oxidant properties in various diseases. Isoproterenol (ISO) has been widely used to establish cardiac injury in vivo and in vitro. However, shikonin function in ISO-induced cardiac injury remains uncertain. In our study, we attempted to investigate the efficiency and possible molecular mechanism of shikonin in cardiac injury treatment induced by ISO. In vivo, C57BL6 mice were subcutaneously injected with 5mg/kg ISO to induce heart failure. And mice were given a gavage of shikonin (2 or 4mg/kg/d, for four weeks). Cardiac function, fibrosis indices, inflammation response, apoptosis and endoplasmic reticulum (ER) stress were calculated. Pathological alterations, fibrosis-, inflammation-, apoptosis- and ER stress-related molecules were examined. In ISO-induced cardiac injury, shikonin significantly ameliorated heart function, decreased myocardial fibrosis, suppressed inflammation, attenuated apoptosis and ER stress through impeding collagen accumulation, Toll like receptor 4/nuclear transcription factor κB (TLR4/NF-κB), Caspase-3 and glucose-regulated protein 78 (GRP78) signaling pathways activity, relieving heart failure in vivo. Also, in vitro, shikonin attenuated ISO-induced cardiac muscle cells by reducing fibrosis, inflammation, apoptosis and ER stress. Our findings indicated that shikonin treatment attenuated ISO-induced heart injury, providing an effective therapeutic strategy for heart failure treatment for future. Copyright © 2017. Published by Elsevier Masson SAS.

  4. Feedback regulation on PTEN/AKT pathway by the ER stress kinase PERK mediated by interaction with the Vault complex

    DEFF Research Database (Denmark)

    Zhang, Wei; Neo, Suat Peng; Gunaratne, Jayantha

    2015-01-01

    The high proliferation rate of cancer cells, together with environmental factors such as hypoxia and nutrient deprivation can cause Endoplasmic Reticulum (ER) stress. The protein kinase PERK is an essential mediator in one of the three ER stress response pathways. Genetic and pharmacological inhi...

  5. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

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    Takushi Namba

    2013-10-01

    Full Text Available Resolved endoplasmic reticulum (ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31 as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  6. Chemical chaperones reduce ER stress and adipose tissue inflammation in high fat diet-induced mouse model of obesity.

    Science.gov (United States)

    Chen, Yaqin; Wu, Zhihong; Zhao, Shuiping; Xiang, Rong

    2016-06-08

    Obesity, which is characteristic by chronic inflammation, is defined as abnormal or excessive fat accumulation in adipose tissues. Endoplasmic reticulum (ER) stress is increased in adipose tissue of obese state and is known to be strongly associated with chronic inflammation. The aim of this study was to investigate the effect of ER stress on adipokine secretion in obese mice and explore the potential mechanisms. In this study, we found high-fat diet induced-obesity contributed to strengthened ER stress and triggered chronic inflammation in adipose tissue. Chemical chaperones, 4-PBA and TUDCA, modified metabolic disorders and decreased the levels of inflammatory cytokines in obese mice fed a high-fat diet. The alleviation of ER stress is in accordance with the decrease of free cholesterol in adipose tissue. Furthermore chemical chaperones suppress NF-κB activity in adipose tissue of obese mice in vivo. In vitro studies showed IKK/NF-κB may be involved in the signal transduction of adipokine secretion dysfunction induced by ER stress. The present study revealed the possibility that inhibition of ER stress may be a novel drug target for metabolic abnormalities associated with obesity. Further studies are now needed to characterize the initial incentive of sustained ER stress in obese.

  7. ER Stress Causes Rapid Loss of Intestinal Epithelial Stemness through Activation of the Unfolded Protein Response

    Directory of Open Access Journals (Sweden)

    Jarom Heijmans

    2013-04-01

    Full Text Available Stem cells generate rapidly dividing transit-amplifying cells that have lost the capacity for self-renewal but cycle for a number of times until they exit the cell cycle and undergo terminal differentiation. We know very little of the type of signals that trigger the earliest steps of stem cell differentiation and mediate a stem cell to transit-amplifying cell transition. We show that in normal intestinal epithelium, endoplasmic reticulum (ER stress and activity of the unfolded protein response (UPR are induced at the transition from stem cell to transit-amplifying cell. Induction of ER stress causes loss of stemness in a Perk-eIF2α-dependent manner. Inhibition of Perk-eIF2α signaling results in stem cell accumulation in organoid culture of primary intestinal epithelium. Our findings show that the UPR plays an important role in the regulation of intestinal epithelial stem cell differentiation.

  8. Dietary gossypol suppressed postprandial TOR signaling and elevated ER stress pathways in turbot (Scophthalmus maximus L.).

    Science.gov (United States)

    Bian, Fuyun; Jiang, Haowen; Man, Mingsan; Mai, Kangsen; Zhou, Huihui; Xu, Wei; He, Gen

    2017-01-01

    Gossypol is known to be a polyphenolic compound toxic to animals. However, its molecular targets are far from fully characterized. To evaluate the physiological and molecular effects of gossypol, we chose turbot (Scophthalmus maximus L.), a carnivorous fish, as our model species. Juvenile turbots (7.83 ± 0.02 g) were fed diets containing gradient levels of gossypol at 0 (G0), 600 (G1), and 1,200 (G2) mg/kg diets for 11 wk. After the feeding trial, fish growth, body protein, and fat contents were significantly reduced in the G2 group compared with those of the G0 group (P TOR) signaling and induced endoplasmic reticulum (ER) stress pathway in both the feeding experiment and cell cultures. Our results demonstrated that gossypol inhibited TOR signaling and elevated ER stress pathways both in vivo and in vitro, thus providing new mechanism of action of gossypol in nutritional physiology. Copyright © 2017 the American Physiological Society.

  9. ER stress responses in the absence of apoptosome: a comparative study in CASP9 proficient vs deficient mouse embryonic fibroblasts.

    Science.gov (United States)

    Deegan, Shane; Saveljeva, Svetlana; Gupta, Sanjeev; MacDonald, David C; Samali, Afshin

    2014-08-29

    Cells respond to endoplasmic reticulum (ER) stress through the unfolded protein response (UPR), autophagy and cell death. In this study we utilized casp9(+/+) and casp9(-/-) MEFs to determine the effect of inhibition of mitochondrial apoptosis pathway on ER stress-induced-cell death, UPR and autophagy. We observed prolonged activation of UPR and autophagy in casp9(-/-) cells as compared with casp9(+/+) MEFs, which displayed transient activation of both pathways. Furthermore we showed that while casp9(-/-) MEFs were resistant to ER stress, prolonged exposure led to the activation of a non-canonical, caspase-mediated mode of cell death. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Calorie-induced ER stress suppresses uroguanylin satiety signaling in diet-induced obesity.

    Science.gov (United States)

    Kim, G W; Lin, J E; Snook, A E; Aing, A S; Merlino, D J; Li, P; Waldman, S A

    2016-05-23

    The uroguanylin-GUCY2C gut-brain axis has emerged as one component regulating feeding, energy homeostasis, body mass and metabolism. Here, we explore a role for this axis in mechanisms underlying diet-induced obesity (DIO). Intestinal uroguanylin expression and secretion, and hypothalamic GUCY2C expression and anorexigenic signaling, were quantified in mice on high-calorie diets for 14 weeks. The role of endoplasmic reticulum (ER) stress in suppressing uroguanylin in DIO was explored using tunicamycin, an inducer of ER stress, and tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress. The impact of consumed calories on uroguanylin expression was explored by dietary manipulation. The role of uroguanylin in mechanisms underlying obesity was examined using Camk2a-Cre-ER(T2)-Rosa-STOP(loxP/loxP)-Guca2b mice in which tamoxifen induces transgenic hormone expression in brain. DIO suppressed intestinal uroguanylin expression and eliminated its postprandial secretion into the circulation. DIO suppressed uroguanylin through ER stress, an effect mimicked by tunicamycin and blocked by TUDCA. Hormone suppression by DIO reflected consumed calories, rather than the pathophysiological milieu of obesity, as a diet high in calories from carbohydrates suppressed uroguanylin in lean mice, whereas calorie restriction restored uroguanylin in obese mice. However, hypothalamic GUCY2C, enriched in the arcuate nucleus, produced anorexigenic signals mediating satiety upon exogenous agonist administration, and DIO did not impair these responses. Uroguanylin replacement by transgenic expression in brain repaired the hormone insufficiency and reconstituted satiety responses opposing DIO and its associated comorbidities, including visceral adiposity, glucose intolerance and hepatic steatosis. These studies reveal a novel pathophysiological mechanism contributing to obesity in which calorie-induced suppression of intestinal uroguanylin impairs hypothalamic mechanisms

  11. Chelerythrine induced cell death through ROS-dependent ER stress in human prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Wu S

    2018-05-01

    Full Text Available Songjiang Wu, Yanying Yang, Feiping Li, Lifu Huang, Zihua Han, Guanfu Wang, Hongyuan Yu, Haiping Li Department of Urology, Enze Hospital of Taizhou Enze Medical Center (Group, Taizhou, China Introduction: Prostate cancer is the most common noncutaneous cancer and the second leading cause of cancer-related mortality worldwide and the third in USA in 2017. Chelerythrine (CHE, a naturalbenzo[c]phenanthridine alkaloid, formerly identified as a protein kinase C inhibitor, has also shown anticancer effect through a number of mechanisms. Herein, effect and mechanism of the CHE-induced apoptosis via reactive oxygen species (ROS-mediated endoplasmic reticulum (ER stress in prostate cancer cells were studied for the first time. Methods: In our present study, we investigated whether CHE induced cell viability decrease, colony formation inhibition, and apoptosis in a dose-dependent manner in PC-3 cells. In addition, we showed that CHE increases intracellular ROS and leads to ROS-dependent ER stress and cell apoptosis. Results: Pre-treatment with N-acetyl cysteine, an ROS scavenger, totally reversed the CHE-induced cancer cell apoptosis as well as ER stress activation, suggesting that the ROS generation was responsible for the anticancer effects of CHE. Conclusion: Taken together, our findings support one of the anticancer mechanisms by which CHE increased ROS accumulation in prostate cancer cells, thereby leading to ER stress and caused intrinsic apoptotic signaling. The study reveals that CHE could be a potential candidate for application in the treatment of prostate cancer. Keywords: chelerythrine, reactive oxygen species, endoplasmic reticulum stress, apoptosis, prostate cancer

  12. Purple perilla extracts allay ER stress in lipid-laden macrophages.

    Directory of Open Access Journals (Sweden)

    Sin-Hye Park

    Full Text Available There is a growing body of evidence that excess lipids, hypoxic stress and other inflammatory signals can stimulate endoplasmic reticulum (ER stress in metabolic diseases. However, the pathophysiological importance and the underlying mechanisms of this phenomenon remain unknown. The current study investigated that 50 ng/ml oxidized LDL promoted unfolded protein response (UPR and ER stress in J774A1 murine macrophages, which was blocked by extracts (PPE of purple Perilla frutescens, a plant of the mint family Lamiaceae. The ER stressor tunicamycin was employed as a positive control. Treating 1-10 µg/ml oxidized LDL for 24 h elicited lipotoxic apoptosis in macrophages with obvious nuclear condensation and DNA fragmentation, which was inhibited by PPE. Tunicamycin and oxidized LDL activated and induced the UPR components of activating transcription factor 6 and ER resident chaperone BiP/Grp78 in temporal manners and such effects were blocked by ≥5 µg/ml PPE. In addition, PPE suppressed the enhanced mRNA transcription and splicing of X-box binding protein 1 (XBP1 by tunicamycin and oxidized LDL. The protein induction and nuclear translocation of XBP1 were deterred in PPE-treated macrophages under ER stress. The induction of ATP-binding cassette transporter A1 (ABCA1, scavenger receptor-B1 (SR-B1 and intracellular adhesion molecule-1 (ICAM-1 was abolished by the ER stressor in activated macrophages. The protein induction of ABCA1 and ICAM1 but not SR-B1 was retrieved by adding 10 µg/ml PPE to cells. These results demonstrate that PPE inhibited lipotoxic apoptosis and demoted the induction and activation of UPR components in macrophages. PPE restored normal proteostasis in activated macrophages oxidized LDL. Therefore, PPE was a potent agent antagonizing macrophage ER stress due to lipotoxic signals associated with atherosclerosis.

  13. Deficiency in the mitochondrial apoptotic pathway reveals the toxic potential of autophagy under ER stress conditions.

    Science.gov (United States)

    Deegan, Shane; Saveljeva, Svetlana; Logue, Susan E; Pakos-Zebrucka, Karolina; Gupta, Sanjeev; Vandenabeele, Peter; Bertrand, Mathieu J M; Samali, Afshin

    2014-01-01

    Endoplasmic reticulum (ER) stress-induced cell death is normally associated with activation of the mitochondrial apoptotic pathway, which is characterized by CYCS (cytochrome c, somatic) release, apoptosome formation, and caspase activation, resulting in cell death. In this study, we demonstrate that under conditions of ER stress cells devoid of CASP9/caspase-9 or BAX and BAK1, and therefore defective in the mitochondrial apoptotic pathway, still undergo a delayed form of cell death associated with the activation of caspases, therefore revealing the existence of an alternative stress-induced caspase activation pathway. We identified CASP8/caspase-8 as the apical protease in this caspase cascade, and found that knockdown of either of the key autophagic genes, ATG5 or ATG7, impacted on CASP8 activation and cell death induction, highlighting the crucial role of autophagy in the activation of this novel ER stress-induced death pathway. In line with this, we identified a protein complex composed of ATG5, FADD, and pro-CASP8 whose assembly coincides with caspase activation and cell death induction. Together, our results reveal the toxic potential of autophagy in cells undergoing ER stress that are defective in the mitochondrial apoptotic pathway, and suggest a model in which the autophagosome functions as a platform facilitating pro-CASP8 activation. Chemoresistance, a common problem in the treatment of cancer, is frequently caused by the downregulation of key mitochondrial death effector proteins. Alternate stress-induced apoptotic pathways, such as the one described here, may become of particular relevance for tackling the problem of chemoresistance in cancer cells.

  14. Exploring the cross talk between ER stress and inflammation in age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Samira Kheitan

    Full Text Available Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER stress is implicated in the development and progression of age-related macular degeneration (AMD, a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.

  15. Exploring the cross talk between ER stress and inflammation in age-related macular degeneration.

    Science.gov (United States)

    Kheitan, Samira; Minuchehr, Zarrin; Soheili, Zahra-Soheila

    2017-01-01

    Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.

  16. Protectin DX suppresses hepatic gluconeogenesis through AMPK-HO-1-mediated inhibition of ER stress.

    Science.gov (United States)

    Jung, Tae Woo; Kim, Hyung-Chun; Abd El-Aty, A M; Jeong, Ji Hoon

    2017-06-01

    Several studies have shown that protectins, which are ω-3 fatty acid-derived proresolution mediators, may improve insulin resistance. Recently, protectin DX (PDX) was documented to attenuate insulin resistance by stimulating IL-6 expression in skeletal muscle, thereby regulating hepatic gluconeogenesis. These findings made us investigate the direct effects of PDX on hepatic glucose metabolism in the context of diabetes. In the current study, we show that PDX regulates hepatic gluconeogenesis in a manner distinct from its indirect glucoregulatory activity via IL-6. We found that PDX stimulated AMP-activated protein kinase (AMPK) phosphorylation, thereby inducing heme oxygenase 1 (HO-1) expression. This induction blocked hepatic gluconeogenesis by suppressing endoplasmic reticulum (ER) stress in hepatocytes under hyperlipidemic conditions. These effects were significantly dampened by silencing AMPK or HO-1 expression with small interfering RNA (siRNA). We also demonstrated that administration of PDX to high fat diet (HFD)-fed mice resulted in increased hepatic AMPK phosphorylation and HO-1 expression, whereas hepatic ER stress was substantially attenuated. Furthermore, PDX treatment suppressed the expression of gluconeogenic genes, thereby decreasing blood glucose levels in HFD-fed mice. In conclusion, our findings suggest that PDX inhibits hepatic gluconeogenesis via AMPK-HO-1-dependent suppression of ER stress. Thus, PDX may be an effective therapeutic target for the treatment of insulin resistance and type 2 diabetes through the regulation of hepatic gluconeogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elżbieta Kania

    2015-01-01

    Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

  18. Armet, a UPR-upregulated protein, inhibits cell proliferation and ER stress-induced cell death

    International Nuclear Information System (INIS)

    Apostolou, Andria; Shen Yuxian; Liang Yan; Luo Jun; Fang Shengyun

    2008-01-01

    The accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress that initiates the unfolded protein response (UPR). UPR activates both adaptive and apoptotic pathways, which contribute differently to disease pathogenesis. To further understand the functional mechanisms of UPR, we identified 12 commonly UPR-upregulated genes by expression microarray analysis. Here, we describe characterization of Armet/MANF, one of the 12 genes whose function was not clear. We demonstrated that the Armet/MANF protein was upregulated by various forms of ER stress in several cell lines as well as by cerebral ischemia of rat. Armet/MANF was localized in the ER and Golgi and was also a secreted protein. Silencing Armet/MANF by siRNA oligos in HeLa cells rendered cells more susceptible to ER stress-induced death, but surprisingly increased cell proliferation and reduced cell size. Overexpression of Armet/MANF inhibited cell proliferation and improved cell viability under glucose-free conditions and tunicamycin treatment. Based on its inhibitory properties for both proliferation and cell death we have demonstrated, Armet is, thus, a novel secreted mediator of the adaptive pathway of UPR

  19. ER Stress-Mediated Signaling: Action Potential and Ca(2+) as Key Players.

    Science.gov (United States)

    Bahar, Entaz; Kim, Hyongsuk; Yoon, Hyonok

    2016-09-15

    The proper functioning of the endoplasmic reticulum (ER) is crucial for multiple cellular activities and survival. Disturbances in the normal ER functions lead to the accumulation and aggregation of unfolded proteins, which initiates an adaptive response, the unfolded protein response (UPR), in order to regain normal ER functions. Failure to activate the adaptive response initiates the process of programmed cell death or apoptosis. Apoptosis plays an important role in cell elimination, which is essential for embryogenesis, development, and tissue homeostasis. Impaired apoptosis can lead to the development of various pathological conditions, such as neurodegenerative and autoimmune diseases, cancer, or acquired immune deficiency syndrome (AIDS). Calcium (Ca(2+)) is one of the key regulators of cell survival and it can induce ER stress-mediated apoptosis in response to various conditions. Ca(2+) regulates cell death both at the early and late stages of apoptosis. Severe Ca(2+) dysregulation can promote cell death through apoptosis. Action potential, an electrical signal transmitted along the neurons and muscle fibers, is important for conveying information to, from, and within the brain. Upon the initiation of the action potential, increased levels of cytosolic Ca(2+) (depolarization) lead to the activation of the ER stress response involved in the initiation of apoptosis. In this review, we discuss the involvement of Ca(2+) and action potential in ER stress-mediated apoptosis.

  20. High-intensity training reduces intermittent hypoxia-induced ER stress and myocardial infarct size.

    Science.gov (United States)

    Bourdier, Guillaume; Flore, Patrice; Sanchez, Hervé; Pepin, Jean-Louis; Belaidi, Elise; Arnaud, Claire

    2016-01-15

    Chronic intermittent hypoxia (IH) is described as the major detrimental factor leading to cardiovascular morbimortality in obstructive sleep apnea (OSA) patients. OSA patients exhibit increased infarct size after a myocardial event, and previous animal studies have shown that chronic IH could be the main mechanism. Endoplasmic reticulum (ER) stress plays a major role in the pathophysiology of cardiovascular disease. High-intensity training (HIT) exerts beneficial effects on the cardiovascular system. Thus, we hypothesized that HIT could prevent IH-induced ER stress and the increase in infarct size. Male Wistar rats were exposed to 21 days of IH (21-5% fraction of inspired O2, 60-s cycle, 8 h/day) or normoxia. After 1 wk of IH alone, rats were submitted daily to both IH and HIT (2 × 24 min, 15-30m/min). Rat hearts were either rapidly frozen to evaluate ER stress by Western blot analysis or submitted to an ischemia-reperfusion protocol ex vivo (30 min of global ischemia/120 min of reperfusion). IH induced cardiac proapoptotic ER stress, characterized by increased expression of glucose-regulated protein kinase 78, phosphorylated protein kinase-like ER kinase, activating transcription factor 4, and C/EBP homologous protein. IH-induced myocardial apoptosis was confirmed by increased expression of cleaved caspase-3. These IH-associated proapoptotic alterations were associated with a significant increase in infarct size (35.4 ± 3.2% vs. 22.7 ± 1.7% of ventricles in IH + sedenary and normoxia + sedentary groups, respectively, P < 0.05). HIT prevented both the IH-induced proapoptotic ER stress and increased myocardial infarct size (28.8 ± 3.9% and 21.0 ± 5.1% in IH + HIT and normoxia + HIT groups, respectively, P = 0.28). In conclusion, these findings suggest that HIT could represent a preventive strategy to limit IH-induced myocardial ischemia-reperfusion damages in OSA patients. Copyright © 2016 the American Physiological Society.

  1. Marinesco-Sjögren syndrome protein SIL1 regulates motor neuron subtype-selective ER stress in ALS

    NARCIS (Netherlands)

    Filézac de L'Etang, Audrey; Maharjan, Niran; Cordeiro Braña, Marisa; Ruegsegger, Céline; Rehmann, Ruth; Goswami, Anand; Roos, Andreas; Troost, Dirk; Schneider, Bernard L.; Weis, Joachim; Saxena, Smita

    2015-01-01

    Mechanisms underlying motor neuron subtype-selective endoplasmic reticulum (ER) stress and associated axonal pathology in amyotrophic lateral sclerosis (ALS) remain unclear. Here we show that the molecular environment of the ER between motor neuron subtypes is distinct, with characteristic

  2. β-cell dysfunction due to increased ER stress in a stem cell model of Wolfram syndrome.

    Science.gov (United States)

    Shang, Linshan; Hua, Haiqing; Foo, Kylie; Martinez, Hector; Watanabe, Kazuhisa; Zimmer, Matthew; Kahler, David J; Freeby, Matthew; Chung, Wendy; LeDuc, Charles; Goland, Robin; Leibel, Rudolph L; Egli, Dieter

    2014-03-01

    Wolfram syndrome is an autosomal recessive disorder caused by mutations in WFS1 and is characterized by insulin-dependent diabetes mellitus, optic atrophy, and deafness. To investigate the cause of β-cell failure, we used induced pluripotent stem cells to create insulin-producing cells from individuals with Wolfram syndrome. WFS1-deficient β-cells showed increased levels of endoplasmic reticulum (ER) stress molecules and decreased insulin content. Upon exposure to experimental ER stress, Wolfram β-cells showed impaired insulin processing and failed to increase insulin secretion in response to glucose and other secretagogues. Importantly, 4-phenyl butyric acid, a chemical protein folding and trafficking chaperone, restored normal insulin synthesis and the ability to upregulate insulin secretion. These studies show that ER stress plays a central role in β-cell failure in Wolfram syndrome and indicate that chemical chaperones might have therapeutic relevance under conditions of ER stress in Wolfram syndrome and other forms of diabetes.

  3. The ER stress-mediated mitochondrial apoptotic pathway and MAPKs modulate tachypacing-induced apoptosis in HL-1 atrial myocytes.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Shi

    Full Text Available Cell apoptosis is a contributing factor in the initiation, progression and relapse of atrial fibrillation (AF, a life-threatening illness accompanied with stroke and heart failure. However, the regulatory cascade of apoptosis is intricate and remains unidentified, especially in the setting of AF. The aim of this study was to explore the roles of endoplasmic reticulum (ER stress, mitochondrial apoptotic pathway (MAP, mitogen-activated protein kinases (MAPKs, and their cross-talking in tachypacing-induced apoptosis.HL-1 cells were cultured in the presence of tachypacing for 24 h to simulate atrial tachycardia remodeling. Results showed that tachypacing reduced cell viability measured by the cell counting kit-8, dissipated mitochondrial membrane potential detected by JC-1 staining and resulted in approximately 50% apoptosis examined by Hoechst staining and annexin V/propidium iodide staining. In addition, the proteins involved in ER stress, MAP and MAPKs were universally up-regulated or activated via phosphorylation, as confirmed by western blotting; and reversely silencing of ER stress, caspase-3 (the ultimate executor of MAP and MAPKs with specific inhibitors prior to pacing partially alleviated apoptosis. An inhibitor of ER stress was applied to further investigate the responses of mitochondria and MAPKs to ER stress, and results indicated that suppression of ER stress comprehensively but incompletely attenuated the activation of MAP and MAPKs aroused by tachypacing, with the exception of ERK1/2, one branch of MAPKs.Our study suggested tachypacing-induced apoptosis is regulated by ER stress-mediated MAP and MAPKs. Thus, the above three components are all promising anti-apoptotic targets in AF patients and ER stress appears to play a dominant role due to its comprehensive effects.

  4. Ursodeoxycholic Acid (UDCA) Exerts Anti-Atherogenic Effects by Inhibiting Endoplasmic Reticulum (ER) Stress Induced by Disturbed Flow.

    Science.gov (United States)

    Chung, Jihwa; Kim, Kyoung Hwa; Lee, Seok Cheol; An, Shung Hyun; Kwon, Kihwan

    2015-10-01

    Disturbed blood flow with low-oscillatory shear stress (OSS) is a predominant atherogenic factor leading to dysfunctional endothelial cells (ECs). Recently, it was found that disturbed flow can directly induce endoplasmic reticulum (ER) stress in ECs, thereby playing a critical role in the development and progression of atherosclerosis. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid, has long been used to treat chronic cholestatic liver disease and is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, its role in atherosclerosis remains unexplored. In this study, we demonstrated the anti-atherogenic activity of UDCA via inhibition of disturbed flow-induced ER stress in atherosclerosis. UDCA effectively reduced ER stress, resulting in a reduction in expression of X-box binding protein-1 (XBP-1) and CEBP-homologous protein (CHOP) in ECs. UDCA also inhibits the disturbed flow-induced inflammatory responses such as increases in adhesion molecules, monocyte adhesion to ECs, and apoptosis of ECs. In a mouse model of disturbed flow-induced atherosclerosis, UDCA inhibits atheromatous plaque formation through the alleviation of ER stress and a decrease in adhesion molecules. Taken together, our results revealed that UDCA exerts anti-atherogenic activity in disturbed flow-induced atherosclerosis by inhibiting ER stress and the inflammatory response. This study suggests that UDCA may be a therapeutic agent for prevention or treatment of atherosclerosis.

  5. Pressure transducers

    International Nuclear Information System (INIS)

    Gomes, A.V.

    1975-01-01

    Strain gauges pressure transducers types are presented. Models, characteristics and calibration procedures were also analysed. Initially, a theoretical study was accomplished to evaluate metallic alloys behavior on sensing elements manufacturing, and diaphragm was used as deflecting elements. Electrical models for potenciometric transducers were proposed at the beginning and subsequently comproved according our experiments. Concerning bridge transducers, existing models confirmed the conditions of linearity and sensitivity related to the electrical signal. All the work done was of help on the calibration field and pressure measurements employing unbounded strain gauge pressure transducers

  6. Increased reactive oxygen species levels cause ER stress and cytotoxicity in andrographolide treated colon cancer cells.

    Science.gov (United States)

    Banerjee, Aditi; Banerjee, Vivekjyoti; Czinn, Steven; Blanchard, Thomas

    2017-04-18

    Chemotherapy continues to play an essential role in the management of many cancers including colon cancer, the third leading cause of death due to cancer in the United States. Many naturally occurring plant compounds have been demonstrated to possess anti-cancer cell activity and have the potential to supplement existing chemotherapy strategies. The plant metabolite andrographolide induces cell death in cancer cells and apoptosis is dependent upon the induction of endoplasmic reticulum stress (ER stress) leading to the unfolded protein response (UPR). The goal of the present study was to determine the mechanism by which andrographolide induces ER stress and to further evaluate its role in promoting cell death pathways. The T84 and COLO 205 cancer cell lines were used to demonstrate that andrographolide induces increased ROS levels, corresponding anti-oxidant response molecules, and reduced mitochondrial membrane potential. No increases in ROS levels were detected in control colon fibroblast cells. Andrographolide-induced cell death, UPR signaling, and CHOP, Bax, and caspase 3 apoptosis elements were all inhibited in the presence of the ROS scavenger NAC. Additionally, andrographolide-induced suppression of cyclins B1 and D1 were also reversed in the presence of NAC. Finally, Akt phosphorylation and phospho-mTOR levels that are normally suppressed by andrographolide were also expressed at normal levels in the absence of ROS. These data demonstrate that andrographolide induces ER stress leading to apoptosis through the induction of ROS and that elevated ROS also play an important role in down-regulating cell cycle progression and cell survival pathways as well.

  7. Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma.

    Science.gov (United States)

    Syed, Deeba N; Lall, Rahul K; Chamcheu, Jean Christopher; Haidar, Omar; Mukhtar, Hasan

    2014-12-01

    The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytotoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up-regulation of ER stress markers including IRE1α, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMP-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity.

  8. Bicyclol attenuates tetracycline-induced fatty liver associated with inhibition of hepatic ER stress and apoptosis in mice.

    Science.gov (United States)

    Yao, Xiao-Min; Li, Yue; Li, Hong-Wei; Cheng, Xiao-Yan; Lin, Ai-Bin; Qu, Jun-Ge

    2016-01-01

    Endoplasmic reticulum (ER) stress is known to be involved in the development of several metabolic disorders, including non-alcoholic fatty liver disease (NAFLD). Tetracycline can cause hepatic steatosis, and ER stress may be involved in tetracycline-induced fatty liver. Our previous study showed that bicyclol has been proven to protect against tetracycline-induced fatty liver in mice, and ER stress may also be involved in bicyclol's hepatoprotective effect. Therefore, this study was performed to investigate the underlying mechanisms associated with ER stress and apoptosis, by which bicyclol attenuated tetracycline-induced fatty liver in mice. Bicyclol (300 mg/kg) was given to mice by gavage 3 times. Tetracycline (200 mg/kg, intraperitoneally) was injected at 1 h after the last dose of bicyclol. At 6 h and 24 h after single dose of tetracycline injection, serum ALT, AST, TG, CHO and hepatic histopathological examinations were performed to evaluate liver injuries. Hepatic steatosis was assessed by the accumulation of hepatic TG and CHO. Moreover, hepatic apoptosis and ER stress related markers were determined by TUNEL, real-time PCR, and western blot. As a result, bicyclol significantly protected against tetracycline-induced fatty liver as evidenced by the decrease of elevated serum transaminases and hepatic triglyceride, and the attenuation of histopathological changes in mice. In addition, bicyclol remarkably alleviated hepatic apoptosis and the gene expression of caspase-3, and increased the gene expression of XIAP. The gene expressions of ER stress-related markers, including CHOP, GRP78, IRE-1α, and ATF6, which were downregulated by bicyclol pretreatment in tetracycline-injected mice. These results suggested that bicyclol protected tetracycline-induced fatty liver partly due to its ability of anti-apoptosis associated with ER stress.

  9. Functional characterization of the ER stress induced X-box-binding protein-1 (Xbp-1 in the porcine system

    Directory of Open Access Journals (Sweden)

    Jin Dong-Il

    2011-05-01

    Full Text Available Abstract Background The unfolded protein response (UPR is an evolutionary conserved adaptive reaction for increasing cell survival under endoplasmic reticulum (ER stress conditions. X-box-binding protein-1 (Xbp1 is a key transcription factor of UPR that activates genes involved in protein folding, secretion, and degradation to restore ER function. The UPR induced by ER stress was extensively studied in diseases linked to protein misfolding and aggregations. However, in the porcine system, genes in the UPR pathway were not investigated. In this study, we isolated and characterized the porcine Xbp1 (pXbp1 gene in ER stress using porcine embryonic fibroblast (PEF cells and porcine organs. ER stress was induced by the treatment of tunicamycin and cell viability was investigated by the MTT assay. For cloning and analyzing the expression pattern of pXbp1, RT-PCR analysis and Western blot were used. Knock-down of pXbp1 was performed by the siRNA-mediated gene silencing. Results We found that the pXbp1 mRNA was the subject of the IRE1α-mediated unconventional splicing by ER stress. Knock-down of pXbp1 enhanced ER stress-mediated cell death in PEF cells. In adult organs, pXbp1 mRNA and protein were expressed and the spliced forms were detected. Conclusions It was first found that the UPR mechanisms and the function of pXbp1 in the porcine system. These results indicate that pXbp1 plays an important role during the ER stress response like other animal systems and open a new opportunity for examining the UPR pathway in the porcine model system.

  10. Pharmacological reduction of ER stress protects against TDP-43 neuronal toxicity in vivo.

    Science.gov (United States)

    Vaccaro, Alexandra; Patten, Shunmoogum A; Aggad, Dina; Julien, Carl; Maios, Claudia; Kabashi, Edor; Drapeau, Pierre; Parker, J Alex

    2013-07-01

    C. elegans and D. rerio expressing mutant TAR DNA Binding Protein 43 (TDP-43) are powerful in vivo animal models for the genetics and pharmacology of amyotrophic lateral sclerosis (ALS). Using these small-animal models of ALS, we previously identified methylene blue (MB) as a potent suppressor of TDP-43 toxicity. Consequently here we investigated how MB might exert its neuroprotective properties and found that it acts through reduction of the endoplasmic reticulum (ER) stress response. We tested other compounds known to be active in the ER unfolded protein response in worms and zebrafish expressing mutant human TDP-43 (mTDP-43). We identified three compounds: salubrinal, guanabenz and a new structurally related compound phenazine, which also reduced paralysis, neurodegeneration and oxidative stress in our mTDP-43 models. Using C. elegans genetics, we showed that all four compounds act as potent suppressors of mTDP-43 toxicity through reduction of the ER stress response. Interestingly, these compounds operate through different branches of the ER unfolded protein pathway to achieve a common neuroprotective action. Our results indicate that protein-folding homeostasis in the ER is an important target for therapeutic development in ALS and other TDP-43-related neurodegenerative diseases. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  11. Programming of Fetal Insulin Resistance in Pregnancies with Maternal Obesity by ER Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Francisco Westermeier

    2014-01-01

    Full Text Available The global epidemics of obesity during pregnancy and excessive gestational weight gain (GWG are major public health problems worldwide. Obesity and excessive GWG are related to several maternal and fetal complications, including diabetes (pregestational and gestational diabetes and intrauterine programming of insulin resistance (IR. Maternal obesity (MO and neonatal IR are associated with long-term development of obesity, diabetes mellitus, and increased global cardiovascular risk in the offspring. Multiple mechanisms of insulin signaling pathway impairment have been described in obese individuals, involving complex interactions of chronically elevated inflammatory mediators, adipokines, and the critical role of the endoplasmic reticulum (ER stress-dependent unfolded protein response (UPR. However, the underlying cellular processes linking MO and IR in the offspring have not been fully elucidated. Here, we summarize the state-of-the-art evidence supporting the possibility that adverse metabolic postnatal outcomes such as IR in the offspring of pregnancies with MO and/or excessive GWG may be related to intrauterine activation of ER stress response.

  12. Programming of Fetal Insulin Resistance in Pregnancies with Maternal Obesity by ER Stress and Inflammation

    Science.gov (United States)

    Sáez, Pablo J.; Villalobos-Labra, Roberto; Farías-Jofré, Marcelo

    2014-01-01

    The global epidemics of obesity during pregnancy and excessive gestational weight gain (GWG) are major public health problems worldwide. Obesity and excessive GWG are related to several maternal and fetal complications, including diabetes (pregestational and gestational diabetes) and intrauterine programming of insulin resistance (IR). Maternal obesity (MO) and neonatal IR are associated with long-term development of obesity, diabetes mellitus, and increased global cardiovascular risk in the offspring. Multiple mechanisms of insulin signaling pathway impairment have been described in obese individuals, involving complex interactions of chronically elevated inflammatory mediators, adipokines, and the critical role of the endoplasmic reticulum (ER) stress-dependent unfolded protein response (UPR). However, the underlying cellular processes linking MO and IR in the offspring have not been fully elucidated. Here, we summarize the state-of-the-art evidence supporting the possibility that adverse metabolic postnatal outcomes such as IR in the offspring of pregnancies with MO and/or excessive GWG may be related to intrauterine activation of ER stress response. PMID:25093191

  13. Xbp1s in Pomc neurons connects ER stress with energy balance and glucose homeostasis.

    Science.gov (United States)

    Williams, Kevin W; Liu, Tiemin; Kong, Xingxing; Fukuda, Makoto; Deng, Yingfeng; Berglund, Eric D; Deng, Zhuo; Gao, Yong; Liu, Tianya; Sohn, Jong-Woo; Jia, Lin; Fujikawa, Teppei; Kohno, Daisuke; Scott, Michael M; Lee, Syann; Lee, Charlotte E; Sun, Kai; Chang, Yongsheng; Scherer, Philipp E; Elmquist, Joel K

    2014-09-02

    The molecular mechanisms underlying neuronal leptin and insulin resistance in obesity and diabetes remain unclear. Here we show that induction of the unfolded protein response transcription factor spliced X-box binding protein 1 (Xbp1s) in pro-opiomelanocortin (Pomc) neurons alone is sufficient to protect against diet-induced obesity as well as improve leptin and insulin sensitivity, even in the presence of strong activators of ER stress. We also demonstrate that constitutive expression of Xbp1s in Pomc neurons contributes to improved hepatic insulin sensitivity and suppression of endogenous glucose production. Notably, elevated Xbp1s levels in Pomc neurons also resulted in activation of the Xbp1s axis in the liver via a cell-nonautonomous mechanism. Together our results identify critical molecular mechanisms linking ER stress in arcuate Pomc neurons to acute leptin and insulin resistance as well as liver metabolism in diet-induced obesity and diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Sirt3-Mediated Autophagy Contributes to Resveratrol-Induced Protection against ER Stress in HT22 Cells

    Directory of Open Access Journals (Sweden)

    Wen-Jun Yan

    2018-02-01

    Full Text Available Endoplasmic reticulum (ER stress occurring in stringent conditions is critically involved in neuronal survival and death. Resveratrol is a non-flavonoid polyphenol that has neuroprotective effects against many neurological disorders. Here, we investigated the potential protective effects of resveratrol in an in vitro ER stress model mimicked by tunicamycin (TM treatment in neuronal HT22 cells. We found that TM dose-dependently decreased cell viability and increased apoptosis, which were both significantly attenuated by resveratrol treatment. Resveratrol markedly reduced the expression or activation of ER stress-associated factors, including GRP78, CHOP, and caspase-12. The results of immunocytochemistry and western blot showed that resveratrol promoted autophagy in TM-treated cells, as evidenced by increased LC3II puncta number, bcelin1 expression and LC3II/LC3I ratio. Pretreatment with the autophagy inhibitor chloroquine could reduce the protective effects of resveratrol. In addition, the expression of Sirt3 protein and its downstream enzyme activities were significantly increased in resveratrol-treated HT22 cells. To confirm the involvement of Sirt3-mediated mechanisms, siRNA transfection was used to knockdown Sirt3 expression in vitro. The results showed that downregulation of Sirt3 could partially prevented the autophagy and protection induced by resveratrol after TM treatment. Our study demonstrates a pivotal role of Sirt3-mediated autophagy in mediating resveratrol-induced protection against ER stress in vitro, and suggests the therapeutic values of resveratrol in ER stress-associated neuronal injury conditions.

  15. Zearalenone altered the cytoskeletal structure via ER stress- autophagy- oxidative stress pathway in mouse TM4 Sertoli cells.

    Science.gov (United States)

    Zheng, Wanglong; Wang, Bingjie; Si, Mengxue; Zou, Hui; Song, Ruilong; Gu, Jianhong; Yuan, Yan; Liu, Xuezhong; Zhu, Guoqiang; Bai, Jianfa; Bian, Jianchun; Liu, ZongPing

    2018-02-20

    The aim of this study was to investigate the molecular mechanisms of the destruction of cytoskeletal structure by Zearalenone (ZEA) in mouse-derived TM4 cells. In order to investigate the role of autophagy, oxidative stress and endoplasmic reticulum(ER) stress in the process of destruction of cytoskeletal structure, the effects of ZEA on the cell viability, cytoskeletal structure, autophagy, oxidative stress, ER stress, MAPK and PI3K- AKT- mTOR signaling pathways were studied. The data demonstrated that ZEA damaged the cytoskeletal structure through the induction of autophagy that leads to the alteration of cytoskeletal structure via elevated oxidative stress. Our results further showed that the autophagy was stimulated by ZEA through PI3K-AKT-mTOR and MAPK signaling pathways in TM4 cells. In addition, ZEA also induced the ER stress which was involved in the induction of the autophagy through inhibiting the ERK signal pathway to suppress the phosphorylation of mTOR. ER stress was involved in the damage of cytoskeletal structure through induction of autophagy by producing ROS. Taken together, this study revealed that ZEA altered the cytoskeletal structure via oxidative stress - autophagy- ER stress pathway in mouse TM4 Sertoli cells.

  16. Implication of altered ubiquitin-proteasome system and ER stress in the muscle atrophy of diabetic rats.

    Science.gov (United States)

    Reddy, S Sreenivasa; Shruthi, Karnam; Prabhakar, Y Konda; Sailaja, Gummadi; Reddy, G Bhanuprakash

    2018-02-01

    Skeletal muscle is adversely affected in type-1 diabetes, and excessively stimulated ubiquitin-proteasome system (UPS) was found to be a leading cause of muscle wasting or atrophy. The role of endoplasmic reticulum (ER) stress in muscle atrophy of type-1 diabetes is not known. Hence, we investigated the role of UPS and ER stress in the muscle atrophy of chronic diabetes rat model. Diabetes was induced with streptozotocin (STZ) in male Sprague-Dawley rats and were sacrificed 2- and 4-months thereafter to collect gastrocnemius muscle. In another experiment, 2-months post-STZ-injection diabetic rats were treated with MG132, a proteasome inhibitor, for the next 2-months and gastrocnemius muscle was collected. The muscle fiber cross-sectional area was diminished in diabetic rats. The expression of UPS components: E1, MURF1, TRIM72, UCHL1, UCHL5, ubiquitinated proteins, and proteasome activity were elevated in the diabetic rats indicating activated UPS. Altered expression of ER-associated degradation (ERAD) components and increased ER stress markers were detected in 4-months diabetic rats. Proteasome inhibition by MG132 alleviated alterations in the UPS and ER stress in diabetic rat muscle. Increased UPS activity and ER stress were implicated in the muscle atrophy of diabetic rats and proteasome inhibition exhibited beneficiary outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Acoustic transducer

    Science.gov (United States)

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  18. Coaxial Transducer

    National Research Council Canada - National Science Library

    Ruffa, Anthony A

    2008-01-01

    The invention as disclosed is of a coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic...

  19. ER stress inhibitor attenuates hearing loss and hair cell death in Cdh23erl/erl mutant mice.

    Science.gov (United States)

    Hu, Juan; Li, Bo; Apisa, Luke; Yu, Heping; Entenman, Shami; Xu, Min; Stepanyan, Ruben; Guan, Bo-Jhih; Müller, Ulrich; Hatzoglou, Maria; Zheng, Qing Yin

    2016-11-24

    Hearing loss is one of the most common sensory impairments in humans. Mouse mutant models helped us to better understand the mechanisms of hearing loss. Recently, we have discovered that the erlong (erl) mutation of the cadherin23 (Cdh23) gene leads to hearing loss due to hair cell apoptosis. In this study, we aimed to reveal the molecular pathways upstream to apoptosis in hair cells to exploit more effective therapeutics than an anti-apoptosis strategy. Our results suggest that endoplasmic reticulum (ER) stress is the earliest molecular event leading to the apoptosis of hair cells and hearing loss in erl mice. We also report that the ER stress inhibitor, Salubrinal (Sal), could delay the progression of hearing loss and preserve hair cells. Our results provide evidence that therapies targeting signaling pathways in ER stress development prevent hair cell apoptosis at an early stage and lead to better outcomes than those targeting downstream factors, such as tip-link degeneration and apoptosis.

  20. Inhibitory Effects of Verrucarin A on Tunicamycin-Induced ER Stress in FaO Rat Liver Cells

    Directory of Open Access Journals (Sweden)

    Eun Young Bae

    2015-05-01

    Full Text Available Endoplasmic reticulum (ER stress is linked with development and maintenance of cancer, and serves as a therapeutic target for treatment of cancer. Verrucarin A, isolated from the broth of Fusarium sp. F060190, showed potential inhibitory activity on tunicamycin-induced ER stress in FaO rat liver cells. In addition, the compound decreased tunicamycin-induced GRP78 promoter activity in a dose dependent manner without inducing significant inhibition of luciferase activity and cell growth for 6 and 12 h. Moreover, the compound decreased the expression of GRP78, CHOP, XBP-1, and suppressed XBP-1, and reduced phosphorylation of IRE1α in FaO rat liver cells. This evidence suggests for the first time that verrucarin A inhibited tunicamycin-induced ER stress in FaO rat liver cells.

  1. Persistent ER stress induces the spliced leader RNA silencing pathway (SLS, leading to programmed cell death in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Hanoch Goldshmidt

    2010-01-01

    Full Text Available Trypanosomes are parasites that cycle between the insect host (procyclic form and mammalian host (bloodstream form. These parasites lack conventional transcription regulation, including factors that induce the unfolded protein response (UPR. However, they possess a stress response mechanism, the spliced leader RNA silencing (SLS pathway. SLS elicits shut-off of spliced leader RNA (SL RNA transcription by perturbing the binding of the transcription factor tSNAP42 to its cognate promoter, thus eliminating trans-splicing of all mRNAs. Induction of endoplasmic reticulum (ER stress in procyclic trypanosomes elicits changes in the transcriptome similar to those induced by conventional UPR found in other eukaryotes. The mechanism of up-regulation under ER stress is dependent on differential stabilization of mRNAs. The transcriptome changes are accompanied by ER dilation and elevation in the ER chaperone, BiP. Prolonged ER stress induces SLS pathway. RNAi silencing of SEC63, a factor that participates in protein translocation across the ER membrane, or SEC61, the translocation channel, also induces SLS. Silencing of these genes or prolonged ER stress led to programmed cell death (PCD, evident by exposure of phosphatidyl serine, DNA laddering, increase in reactive oxygen species (ROS production, increase in cytoplasmic Ca(2+, and decrease in mitochondrial membrane potential, as well as typical morphological changes observed by transmission electron microscopy (TEM. ER stress response is also induced in the bloodstream form and if the stress persists it leads to SLS. We propose that prolonged ER stress induces SLS, which serves as a unique death pathway, replacing the conventional caspase-mediated PCD observed in higher eukaryotes.

  2. Aberrant accumulation of the diabetes autoantigen GAD65 in Golgi membranes in conditions of ER stress and autoimmunity

    DEFF Research Database (Denmark)

    Phelps, Edward A; Cianciaruso, Chiara; Michael, Iacovos P

    2016-01-01

    Pancreatic islet beta cells are particularly susceptible to endoplasmic reticulum (ER) stress, which is implicated in beta cell dysfunction and loss during the pathogenesis of type 1 diabetes (T1D). The peripheral membrane protein GAD65 is an autoantigen in human T1D. GAD65 synthesizes GABA......, an important autocrine and paracrine signaling molecule and a survival factor in islets. We show that ER stress in primary beta cells perturbs the palmitoylation cycle controlling GAD65 endomembrane distribution, resulting in aberrant accumulation of the palmitoylated form in trans-Golgi membranes...... release from stressed and/or damaged beta cells, triggering autoimmunity....

  3. The intersection between growth factors, autophagy and ER stress: A new target to treat neurodegenerative diseases?

    Science.gov (United States)

    Garcia-Huerta, Paula; Troncoso-Escudero, Paulina; Jerez, Carolina; Hetz, Claudio; Vidal, Rene L

    2016-10-15

    One of the salient features of most neurodegenerative diseases is the aggregation of specific proteins in the brain. This proteostasis imbalance is proposed as a key event triggering the neurodegenerative cascade. The unfolded protein response (UPR) and autophagy pathways are emerging as critical processes implicated in handling disease-related misfolded proteins. However, in some conditions, perturbations in the buffering capacity of the proteostasis network may be part of the etiology of the disease. Thus, pharmacological or gene therapy strategies to enhance autophagy or UPR responses are becoming an attractive target for disease intervention. Here, we discuss current evidence depicting the complex involvement of autophagy and ER stress in brain diseases. Novel pathways to modulate protein misfolding are discussed including the relation between aging and growth factor signaling. This article is part of a Special Issue entitled SI:Autophagy. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. ER stress signaling and neurodegeneration: At the intersection between Alzheimer's disease and Prion-related disorders.

    Science.gov (United States)

    Torres, Mauricio; Matamala, José Manuel; Duran-Aniotz, Claudia; Cornejo, Victor Hugo; Foley, Andrew; Hetz, Claudio

    2015-09-02

    Alzheimer's and Prion diseases are two neurodegenerative conditions sharing different pathophysiological characteristics. Disease symptoms are associated with the abnormal accumulation of protein aggregates, which are generated by the misfolding and oligomerization of specific proteins. Recent functional studies uncovered a key role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in the occurrence of synaptic dysfunction and neurodegeneration in Prion-related disorders and Alzheimer's disease. Here we review common pathological features of both diseases, emphasizing the link between amyloid formation, its pathogenesis and alterations in ER proteostasis. The potential benefits of targeting the UPR as a therapeutic strategy is also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. DON shares a similar mode of action as the ribotoxic stress inducer anisomycin while TBTO shares ER stress patterns with the ER stress inducer Thapsigargin based on comparative gene expression profiling in Jurkat T cells

    NARCIS (Netherlands)

    Schmeits, P.C.J.; Katika, M.R.; Peijnenburg, A.A.C.M.; Loveren, van H.; Hendriksen, P.J.M.

    2014-01-01

    Previously, we studied the effects of deoxynivalenol (DON) and tributyltin oxide (TBTO) on whole genome mRNA expression profiles of human T lymphocyte Jurkat cells. These studies indicated that DON induces ribotoxic stress and both DON and TBTO induced ER stress which resulted into T-cell activation

  6. Effects of Fat and Sugar, Either Consumed or Infused toward the Brain, on Hypothalamic ER Stress Markers

    NARCIS (Netherlands)

    Belegri, Evita; Rijnsburger, Merel; Eggels, Leslie; Unmehopa, Unga; Scheper, Wiep; Boelen, Anita; la Fleur, Susanne E.

    2017-01-01

    Protein-folding stress at the Endoplasmic Reticulum (ER) occurs in the hypothalamus during diet-induced obesity (DIO) and is linked to metabolic disease development. ER stress is buffered by the activation of the unfolded protein response (UPR), a controlled network of pathways inducing a set of

  7. Effect of the unfolded protein response on ER protein export: a potential new mechanism to relieve ER stress.

    Science.gov (United States)

    Shaheen, Alaa

    2018-05-05

    The unfolded protein response (UPR) is an adaptive cellular response that aims to relieve endoplasmic reticulum (ER) stress via several mechanisms, including inhibition of protein synthesis and enhancement of protein folding and degradation. There is a controversy over the effect of the UPR on ER protein export. While some investigators suggested that ER export is inhibited during ER stress, others suggested the opposite. In this article, their conflicting studies are analyzed and compared in attempt to solve this controversy. The UPR appears indeed to enhance ER export, possibly via multiple mechanisms. However, another factor, which is the integrity of the folding machinery/environment inside ER, determines whether ER export will appear increased or decreased during experimentation. Also, different methods of stress induction appear to have different effects on ER export. Thus, improvement of ER export may represent a new mechanism by which the UPR alleviates ER stress. This may help researchers to understand how the UPR works inside cells and how to manipulate it to alter cell fate during stress, either to promote cell survival or death. This may open up new approaches for the treatment of ER stress-related diseases.

  8. Up-regulation of Kir2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    International Nuclear Information System (INIS)

    Kito, Hiroaki; Yamazaki, Daiju; Ohya, Susumu; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

    2011-01-01

    Highlights: → We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. → The ER stress facilitated the expression of inward rectifier K + channel (K ir 2.1) and induced sustained membrane hyperpolarization. → The membrane hyperpolarization induced sustained Ca 2+ entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. → The K ir 2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K + channel (K ir 2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K ir channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca 2+ concentration due to Ca 2+ influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K ir 2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  9. CCAAT/Enhancer Binding Protein β in relation to ER Stress, Inflammation, and Metabolic Disturbances

    Directory of Open Access Journals (Sweden)

    Sophie E. van der Krieken

    2015-01-01

    Full Text Available The prevalence of the metabolic syndrome and underlying metabolic disturbances increase rapidly in developed countries. Various molecular targets are currently under investigation to unravel the molecular mechanisms that cause these disturbances. This is done in attempt to counter or prevent the negative health consequences of the metabolic disturbances. Here, we reviewed the current knowledge on the role of C/EBP-β in these metabolic disturbances. C/EBP-β deletion in mice resulted in downregulation of hepatic lipogenic genes and increased expression of β-oxidation genes in brown adipose tissue. Furthermore, C/EBP-β is important in the differentiation and maturation of adipocytes and is increased during ER stress and proinflammatory conditions. So far, studies were only conducted in animals and in cell systems. The results found that C/EBP-β is an important transcription factor within the metabolic disturbances of the metabolic system. Therefore, it is interesting to examine the potential role of C/EBP-β at molecular and physiological level in humans.

  10. A sphingolipid-dependent diffusion barrier confines ER stress to the yeast mother cell

    Science.gov (United States)

    Clay, Lori; Caudron, Fabrice; Denoth-Lippuner, Annina; Boettcher, Barbara; Buvelot Frei, Stéphanie; Snapp, Erik Lee; Barral, Yves

    2014-01-01

    In many cell types, lateral diffusion barriers compartmentalize the plasma membrane and, at least in budding yeast, the endoplasmic reticulum (ER). However, the molecular nature of these barriers, their mode of action and their cellular functions are unclear. Here, we show that misfolded proteins of the ER remain confined into the mother compartment of budding yeast cells. Confinement required the formation of a lateral diffusion barrier in the form of a distinct domain of the ER-membrane at the bud neck, in a septin-, Bud1 GTPase- and sphingolipid-dependent manner. The sphingolipids, but not Bud1, also contributed to barrier formation in the outer membrane of the dividing nucleus. Barrier-dependent confinement of ER stress into the mother cell promoted aging. Together, our data clarify the physical nature of lateral diffusion barriers in the ER and establish the role of such barriers in the asymmetric segregation of proteotoxic misfolded proteins during cell division and aging. DOI: http://dx.doi.org/10.7554/eLife.01883.001 PMID:24843009

  11. Structure-activity relationship of piperine and its synthetic amide analogs for therapeutic potential to prevent experimentally induced ER stress in vitro.

    Science.gov (United States)

    Hammad, Ayat S; Ravindran, Sreenithya; Khalil, Ashraf; Munusamy, Shankar

    2017-05-01

    Endoplasmic reticulum (ER) is the key organelle involved in protein folding and maturation. Emerging studies implicate the role of ER stress in the development of chronic kidney disease. Thus, there is an urgent need for compounds that could ameliorate ER stress and prevent CKD. Piperine and its analogs have been reported to exhibit multiple pharmacological activities; however, their efficacy against ER stress in kidney cells has not been studied yet. Hence, the goal of this study was to synthesize amide-substituted piperine analogs and screen them for pharmacological activity to relieve ER stress using an in vitro model of tunicamycin-induced ER stress using normal rat kidney (NRK-52E) cells. Five amide-substituted piperine analogs were synthesized and their chemical structures were elucidated by pertinent spectroscopic techniques. An in vitro model of ER stress was developed using tunicamycin, and the compounds of interest were screened for their effect on cell viability, and the expression of ER chaperone GRP78, the pro-apoptotic ER stress marker CHOP, and apoptotic caspases 3 and 12 (via western blotting). Our findings indicate that exposure to tunicamycin (0.5 μg/mL) for 2 h induces the expression of GRP78 and CHOP, and apoptotic markers (caspase-3 and caspase-12) and causes a significant reduction in renal cell viability. Pre-treatment of cells with piperine and its cyclohexylamino analog decreased the tunicamycin-induced upregulation of GRP78 and CHOP and cell death. Taken together, our findings demonstrate that piperine and its analogs differentially regulate ER stress, and thus represent potential therapeutic agents to treat ER stress-related renal disorders. Graphical Abstract Piperine (PIP) reduces the expression of ER stress markers (GRP78 and CHOP) induced by pathologic stimuli and consequently decreases the activation of apoptotic caspase-12 and caspase-3; all of which contributes to its chemical chaperone and cytoprotective properties to protect

  12. Spliced leader RNA silencing (SLS - a programmed cell death pathway in Trypanosoma brucei that is induced upon ER stress

    Directory of Open Access Journals (Sweden)

    Michaeli Shulamit

    2012-05-01

    Full Text Available Abstract Trypanosoma brucei is the causative agent of African sleeping sickness. The parasite cycles between its insect (procyclic form and mammalian hosts (bloodstream form. Trypanosomes lack conventional transcription regulation, and their genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon, the spliced leader (SL is added to all mRNAs from a small RNA, the SL RNA. Trypanosomes lack the machinery for the unfolded protein response (UPR, which in other eukaryotes is induced under endoplasmic reticulum (ER stress. Trypanosomes respond to such stress by changing the stability of mRNAs, which are essential for coping with the stress. However, under severe ER stress that is induced by blocking translocation of proteins to the ER, treatment of cells with chemicals that induce misfolding in the ER, or extreme pH, trypanosomes elicit the spliced leader silencing (SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and tSNAP42, a specific SL RNA transcription factor, fails to bind to its cognate promoter. SLS leads to complete shut-off of trans-splicing. In this review, I discuss the UPR in mammals and compare it to the ER stress response in T. brucei leading to SLS. I summarize the evidence supporting the notion that SLS is a programmed cell death (PCD pathway that is utilized by the parasites to substitute for the apoptosis observed in higher eukaryotes under prolonged ER stress. I present the hypothesis that SLS evolved to expedite the death process, and rapidly remove from the population unfit parasites that, by elimination via SLS, cause minimal damage to the parasite population.

  13. Role of ER stress response in photodynamic therapy: ROS generated in different subcellular compartments trigger diverse cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Moserová, Irena; Králová, Jarmila

    2012-01-01

    Roč. 7, č. 3 (2012), e32972 E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LC06077; GA ČR GA203/09/1311; GA ČR(CZ) GAP303/11/1291 Institutional research plan: CEZ:AV0Z50520514 Keywords : photodynamic therapy * porphyrin derivatives * cell death * ER stress Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.730, year: 2012

  14. The metabolic ER stress sensor IRE1α suppresses alternative activation of macrophages and impairs energy expenditure in obesity.

    Science.gov (United States)

    Shan, Bo; Wang, Xiaoxia; Wu, Ying; Xu, Chi; Xia, Zhixiong; Dai, Jianli; Shao, Mengle; Zhao, Feng; He, Shengqi; Yang, Liu; Zhang, Mingliang; Nan, Fajun; Li, Jia; Liu, Jianmiao; Liu, Jianfeng; Jia, Weiping; Qiu, Yifu; Song, Baoliang; Han, Jing-Dong J; Rui, Liangyou; Duan, Sheng-Zhong; Liu, Yong

    2017-05-01

    Obesity is associated with metabolic inflammation and endoplasmic reticulum (ER) stress, both of which promote metabolic disease progression. Adipose tissue macrophages (ATMs) are key players orchestrating metabolic inflammation, and ER stress enhances macrophage activation. However, whether ER stress pathways underlie ATM regulation of energy homeostasis remains unclear. Here, we identified inositol-requiring enzyme 1α (IRE1α) as a critical switch governing M1-M2 macrophage polarization and energy balance. Myeloid-specific IRE1α abrogation in Ern1 f/f ; Lyz2-Cre mice largely reversed high-fat diet (HFD)-induced M1-M2 imbalance in white adipose tissue (WAT) and blocked HFD-induced obesity, insulin resistance, hyperlipidemia and hepatic steatosis. Brown adipose tissue (BAT) activity, WAT browning and energy expenditure were significantly higher in Ern1 f/f ; Lyz2-Cre mice. Furthermore, IRE1α ablation augmented M2 polarization of macrophages in a cell-autonomous manner. Thus, IRE1α senses protein unfolding and metabolic and immunological states, and consequently guides ATM polarization. The macrophage IRE1α pathway drives obesity and metabolic syndrome through impairing BAT activity and WAT browning.

  15. The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Li, Jingzhi; Sha, Bingdong

    2016-11-29

    PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.

  16. ER stress in retinal degeneration in S334ter Rho rats.

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    Vishal M Shinde

    Full Text Available The S334ter rhodopsin (Rho rat (line 4 bears the rhodopsin gene with an early termination codon at residue 334 that is a model for several such mutations found in human patients with autosomal dominant retinitis pigmentosa (ADRP. The Unfolded Protein Response (UPR is implicated in the pathophysiology of several retinal disorders including ADRP in P23H Rho rats. The aim of this study was to examine the onset of UPR gene expression in S334ter Rho retinas to determine if UPR is activated in ADRP animal models and to investigate how the activation of UPR molecules leads to the final demise of S334ter Rho photoreceptors. RT-PCR was performed to evaluate the gene expression profiles for the P10, P12, P15, and P21 stages of the development and progression of ADRP in S334ter Rho photoreceptors. We determined that during the P12-P15 period, ER stress-related genes are strongly upregulated in transgenic retinas, resulting in the activation of the UPR that was confirmed using western blot analysis and RT-PCR. The activation of UPR was associated with the increased expression of JNK, Bik, Bim, Bid, Noxa, and Puma genes and cleavage of caspase-12 that together with activated calpains presumably compromise the integrity of the mitochondrial MPTP, leading to the release of pro-apoptotic AIF1 into the cytosol of S334ter Rho photoreceptor cells. Therefore, two major cross-talking pathways, the UPR and mitochondrial MPTP occur in S334ter-4 Rho retina concomitantly and eventually promote the death of the photoreceptor cells.

  17. 2-Chlorohexadecanoic acid induces ER stress and mitochondrial dysfunction in brain microvascular endothelial cells

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    Eva Bernhart

    2018-05-01

    Full Text Available Peripheral leukocytes induce blood-brain barrier (BBB dysfunction through the release of cytotoxic mediators. These include hypochlorous acid (HOCl that is formed via the myeloperoxidase-H2O2-chloride system of activated phagocytes. HOCl targets the endogenous pool of ether phospholipids (plasmalogens generating chlorinated inflammatory mediators like e.g. 2-chlorohexadecanal and its conversion product 2-chlorohexadecanoic acid (2-ClHA. In the cerebrovasculature these compounds inflict damage to brain microvascular endothelial cells (BMVEC that form the morphological basis of the BBB. To follow subcellular trafficking of 2-ClHA we synthesized a ‘clickable’ alkyne derivative (2-ClHyA that phenocopied the biological activity of the parent compound. Confocal and superresolution structured illumination microscopy revealed accumulation of 2-ClHyA in the endoplasmic reticulum (ER and mitochondria of human BMVEC (hCMEC/D3 cell line. 2-ClHA and its alkyne analogue interfered with protein palmitoylation, induced ER-stress markers, reduced the ER ATP content, and activated transcription and secretion of interleukin (IL−6 as well as IL-8. 2-ClHA disrupted the mitochondrial membrane potential and induced procaspase-3 and PARP cleavage. The protein kinase R-like ER kinase (PERK inhibitor GSK2606414 suppressed 2-ClHA-mediated activating transcription factor 4 synthesis and IL-6/8 secretion, but showed no effect on endothelial barrier dysfunction and cleavage of procaspase-3. Our data indicate that 2-ClHA induces potent lipotoxic responses in brain endothelial cells and could have implications in inflammation-induced BBB dysfunction.

  18. ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis

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    Diane DeZwaan-McCabe

    2017-05-01

    Full Text Available The unfolded protein response (UPR, induced by endoplasmic reticulum (ER stress, regulates the expression of factors that restore protein folding homeostasis. However, in the liver and kidney, ER stress also leads to lipid accumulation, accompanied at least in the liver by transcriptional suppression of metabolic genes. The mechanisms of this accumulation, including which pathways contribute to the phenotype in each organ, are unclear. We combined gene expression profiling, biochemical assays, and untargeted lipidomics to understand the basis of stress-dependent lipid accumulation, taking advantage of enhanced hepatic and renal steatosis in mice lacking the ER stress sensor ATF6α. We found that impaired fatty acid oxidation contributed to the early development of steatosis in the liver but not the kidney, while anorexia-induced lipolysis promoted late triglyceride and free fatty acid accumulation in both organs. These findings provide evidence for both direct and indirect regulation of peripheral metabolism by ER stress.

  19. HSP72 protects cells from ER stress-induced apoptosis via enhancement of IRE1alpha-XBP1 signaling through a physical interaction.

    LENUS (Irish Health Repository)

    Gupta, Sanjeev

    2010-01-01

    Endoplasmic reticulum (ER) stress is a feature of secretory cells and of many diseases including cancer, neurodegeneration, and diabetes. Adaptation to ER stress depends on the activation of a signal transduction pathway known as the unfolded protein response (UPR). Enhanced expression of Hsp72 has been shown to reduce tissue injury in response to stress stimuli and improve cell survival in experimental models of stroke, sepsis, renal failure, and myocardial ischemia. Hsp72 inhibits several features of the intrinsic apoptotic pathway. However, the molecular mechanisms by which Hsp72 expression inhibits ER stress-induced apoptosis are not clearly understood. Here we show that Hsp72 enhances cell survival under ER stress conditions. The UPR signals through the sensor IRE1alpha, which controls the splicing of the mRNA encoding the transcription factor XBP1. We show that Hsp72 enhances XBP1 mRNA splicing and expression of its target genes, associated with attenuated apoptosis under ER stress conditions. Inhibition of XBP1 mRNA splicing either by dominant negative IRE1alpha or by knocking down XBP1 specifically abrogated the inhibition of ER stress-induced apoptosis by Hsp72. Regulation of the UPR was associated with the formation of a stable protein complex between Hsp72 and the cytosolic domain of IRE1alpha. Finally, Hsp72 enhanced the RNase activity of recombinant IRE1alpha in vitro, suggesting a direct regulation. Our data show that binding of Hsp72 to IRE1alpha enhances IRE1alpha\\/XBP1 signaling at the ER and inhibits ER stress-induced apoptosis. These results provide a physical connection between cytosolic chaperones and the ER stress response.

  20. Palmitate-induced ER stress and inhibition of protein synthesis in cultured myotubes does not require Toll-like receptor 4.

    Science.gov (United States)

    Perry, Ben D; Rahnert, Jill A; Xie, Yang; Zheng, Bin; Woodworth-Hobbs, Myra E; Price, S Russ

    2018-01-01

    Saturated fatty acids, such as palmitate, are elevated in metabolically dysfunctional conditions like type 2 diabetes mellitus. Palmitate has been shown to impair insulin sensitivity and suppress protein synthesis while upregulating proteolytic systems in skeletal muscle. Increased sarco/endoplasmic reticulum (ER) stress and subsequent activation of the unfolded protein response may contribute to the palmitate-induced impairment of muscle protein synthesis. In some cell types, ER stress occurs through activation of the Toll-like receptor 4 (TLR4). Given the link between ER stress and suppression of protein synthesis, we investigated whether palmitate induces markers of ER stress and protein synthesis by activating TLR4 in cultured mouse C2C12 myotubes. Myotubes were treated with vehicle, a TLR4-specific ligand (lipopolysaccharides), palmitate, or a combination of palmitate plus a TLR4-specific inhibitor (TAK-242). Inflammatory indicators of TLR4 activation (IL-6 and TNFα) and markers of ER stress were measured, and protein synthesis was assessed using puromycin incorporation. Palmitate substantially increased the levels of IL-6, TNF-α, CHOP, XBP1s, and ATF 4 mRNAs and augmented the levels of CHOP, XBP1s, phospho-PERK and phospho-eIF2α proteins. The TLR4 antagonist attenuated both acute palmitate and LPS-induced increases in IL-6 and TNFα, but did not reduce ER stress signaling with either 6 h or 24 h palmitate treatment. Similarly, treating myotubes with palmitate for 6 h caused a 43% decline in protein synthesis consistent with an increase in phospho-eIF2α, and the TLR4 antagonist did not alter these responses. These results suggest that palmitate does not induce ER stress through TLR4 in muscle, and that palmitate impairs protein synthesis in skeletal muscle in part by induction of ER stress.

  1. HSP72 protects cells from ER stress-induced apoptosis via enhancement of IRE1alpha-XBP1 signaling through a physical interaction.

    Directory of Open Access Journals (Sweden)

    Sanjeev Gupta

    2010-07-01

    Full Text Available Endoplasmic reticulum (ER stress is a feature of secretory cells and of many diseases including cancer, neurodegeneration, and diabetes. Adaptation to ER stress depends on the activation of a signal transduction pathway known as the unfolded protein response (UPR. Enhanced expression of Hsp72 has been shown to reduce tissue injury in response to stress stimuli and improve cell survival in experimental models of stroke, sepsis, renal failure, and myocardial ischemia. Hsp72 inhibits several features of the intrinsic apoptotic pathway. However, the molecular mechanisms by which Hsp72 expression inhibits ER stress-induced apoptosis are not clearly understood. Here we show that Hsp72 enhances cell survival under ER stress conditions. The UPR signals through the sensor IRE1alpha, which controls the splicing of the mRNA encoding the transcription factor XBP1. We show that Hsp72 enhances XBP1 mRNA splicing and expression of its target genes, associated with attenuated apoptosis under ER stress conditions. Inhibition of XBP1 mRNA splicing either by dominant negative IRE1alpha or by knocking down XBP1 specifically abrogated the inhibition of ER stress-induced apoptosis by Hsp72. Regulation of the UPR was associated with the formation of a stable protein complex between Hsp72 and the cytosolic domain of IRE1alpha. Finally, Hsp72 enhanced the RNase activity of recombinant IRE1alpha in vitro, suggesting a direct regulation. Our data show that binding of Hsp72 to IRE1alpha enhances IRE1alpha/XBP1 signaling at the ER and inhibits ER stress-induced apoptosis. These results provide a physical connection between cytosolic chaperones and the ER stress response.

  2. Globular adiponectin protects rat hepatocytes against acetaminophen-induced cell death via modulation of the inflammasome activation and ER stress: Critical role of autophagy induction.

    Science.gov (United States)

    Kim, Eun Hye; Park, Pil-Hoon

    2018-05-24

    Acetaminophen (APAP) overdose treatment causes severe liver injury. Adiponectin, a hormone predominantly produced by adipose tissue, exhibits protective effects against APAP-induced hepatotoxicity. However, the underlying mechanisms are not clearly understood. In the present study, we examined the protective effect of globular adiponectin (gAcrp) on APAP-induced hepatocyte death and its underlying mechanisms. We found that APAP (2 mM)-induced hepatocyte death was prevented by inhibition of the inflammasome. In addition, treatment with gAcrp (0.5 and 1 μg/ml) inhibited APAP-induced activation of the inflammasome, judged by suppression of interleukin-1β maturation, caspase-1 activation, and apoptosis-associated speck-like protein (ASC) speck formation, suggesting that protective effects of gAcrp against APAP-induced hepatocyte death is mediated via modulation of the inflammasome. APAP also induced ER stress and treatment with tauroursodeoxycholic acid (TUDCA), an ER chaperone and inhibitor of ER stress, abolished APAP-induced inflammasomes activation, implying that ER stress acts as signaling event leading to the inflammasome activation in hepatocytes stimulated with APAP. Moreover, gAcrp significantly suppressed APAP-induced expression of ER stress marker genes. Finally, the modulatory effects of gAcrp on ER stress and inflammasomes activation were abrogated by treatment with autophagy inhibitors, while an autophagy inducer (rapamycin) suppressed APAP-elicited ER stress, demonstrating that autophagy induction plays a crucial role in the suppression of APAP-induced inflammasome activation and ER stress by gAcrp. Taken together, these results indicate that gAcrp protects hepatocytes against APAP-induced cell death by modulating ER stress and the inflammasome activation, at least in part, via autophagy induction. Copyright © 2018. Published by Elsevier Inc.

  3. Palmitate-induced ER stress and inhibition of protein synthesis in cultured myotubes does not require Toll-like receptor 4.

    Directory of Open Access Journals (Sweden)

    Ben D Perry

    Full Text Available Saturated fatty acids, such as palmitate, are elevated in metabolically dysfunctional conditions like type 2 diabetes mellitus. Palmitate has been shown to impair insulin sensitivity and suppress protein synthesis while upregulating proteolytic systems in skeletal muscle. Increased sarco/endoplasmic reticulum (ER stress and subsequent activation of the unfolded protein response may contribute to the palmitate-induced impairment of muscle protein synthesis. In some cell types, ER stress occurs through activation of the Toll-like receptor 4 (TLR4. Given the link between ER stress and suppression of protein synthesis, we investigated whether palmitate induces markers of ER stress and protein synthesis by activating TLR4 in cultured mouse C2C12 myotubes. Myotubes were treated with vehicle, a TLR4-specific ligand (lipopolysaccharides, palmitate, or a combination of palmitate plus a TLR4-specific inhibitor (TAK-242. Inflammatory indicators of TLR4 activation (IL-6 and TNFα and markers of ER stress were measured, and protein synthesis was assessed using puromycin incorporation. Palmitate substantially increased the levels of IL-6, TNF-α, CHOP, XBP1s, and ATF 4 mRNAs and augmented the levels of CHOP, XBP1s, phospho-PERK and phospho-eIF2α proteins. The TLR4 antagonist attenuated both acute palmitate and LPS-induced increases in IL-6 and TNFα, but did not reduce ER stress signaling with either 6 h or 24 h palmitate treatment. Similarly, treating myotubes with palmitate for 6 h caused a 43% decline in protein synthesis consistent with an increase in phospho-eIF2α, and the TLR4 antagonist did not alter these responses. These results suggest that palmitate does not induce ER stress through TLR4 in muscle, and that palmitate impairs protein synthesis in skeletal muscle in part by induction of ER stress.

  4. Morbillivirus glycoprotein expression induces ER stress, alters Ca2+ homeostasis and results in the release of vasostatin.

    Directory of Open Access Journals (Sweden)

    Jean-Marc Brunner

    Full Text Available Although the pathology of Morbillivirus in the central nervous system (CNS is well described, the molecular basis of neurodegenerative events still remains poorly understood. As a model to explore Morbillivirus-mediated CNS dysfunctions, we used canine distemper virus (CDV that we inoculated into two different cell systems: a monkey cell line (Vero and rat primary hippocampal neurons. Importantly, the recombinant CDV used in these studies not only efficiently infects both cell types but recapitulates the uncommon, non-cytolytic cell-to-cell spread mediated by virulent CDVs in brain of dogs. Here, we demonstrated that both CDV surface glycoproteins (F and H markedly accumulated in the endoplasmic reticulum (ER. This accumulation triggered an ER stress, characterized by increased expression of the ER resident chaperon calnexin and the proapoptotic transcription factor CHOP/GADD 153. The expression of calreticulin (CRT, another ER resident chaperon critically involved in the response to misfolded proteins and in Ca(2+ homeostasis, was also upregulated. Transient expression of recombinant CDV F and H surface glycoproteins in Vero cells and primary hippocampal neurons further confirmed a correlation between their accumulation in the ER, CRT upregulation, ER stress and disruption of ER Ca(2+ homeostasis. Furthermore, CDV infection induced CRT fragmentation with re-localisation of a CRT amino-terminal fragment, also known as vasostatin, on the surface of infected and neighbouring non-infected cells. Altogether, these results suggest that ER stress, CRT fragmentation and re-localization on the cell surface may contribute to cytotoxic effects and ensuing cell dysfunctions triggered by Morbillivirus, a mechanism that might potentially be relevant for other neurotropic viruses.

  5. Inhibition of advanced glycation endproduct (AGE) rescues against streptozotocin-induced diabetic cardiomyopathy: Role of autophagy and ER stress.

    Science.gov (United States)

    Pei, Zhaohui; Deng, Qinqin; Babcock, Sara A; He, Emily Y; Ren, Jun; Zhang, Yingmei

    2018-03-01

    Diabetes mellitus leads to oxidative stress and contractile dysfunction in the heart. Although several rationales have been speculated, the precise mechanism behind diabetic cardiomyopathy remains elusive. This study was designed to assess the role of inhibition of advanced glycation endproducts (AGE) in streptozotocin (STZ)-induced diabetic cardiac dysfunction. Cardiac contractile function was assessed in normal C57BL/6 and STZ (200mg/kg, single injection and maintained for 2 wks)-induced diabetic mice treated with or without the AGE inhibitor aminoguanidine (50mg/kg/d in drinking water) for 2 weeks using echocardiography and IonOptix MyoCam techniques. Diabetes compromised cardiac contractile function shown as reduced fractional shortening and ejection fraction, enlarged left ventricular end systolic/diastolic diameters, decreased peak shortening, maximal velocity of shortening/relengthening, prolonged shortening and relengthening duration as well as impaired intracellular Ca 2+ homeostasis, the effects of which were alleviated or reversed by aminoguanidine treatment. Diabetes also inhibited autophagy, increased ER stress and phosphorylation of pro-hypertrophic signaling molecules Akt and mTOR, the effect of which was reversed by aminoguanidine. In vitro study revealed that methylglyoxal-derived AGE (MG-AGE) incubation in isolated cardiomyocytes promoted oxidation of sarco(endo)plasmic reticulum Ca 2+ -ATPase (SERCA2a) and production of superoxide, the effects of which were negated by the autophagy inducer rapamycin, the ER stress chaperone TUDCA or the antioxidant N-acetylcysteine. Taken together, these data revealed that inhibition of AGE formation rescues against experimental diabetes-induced cardiac remodeling and contractile dysfunction possible through regulation of autophagy and ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Jolkinolide B induces apoptosis of colorectal carcinoma through ROS-ER stress-Ca2+-mitochondria dependent pathway.

    Science.gov (United States)

    Zhang, Jing; Wang, Yang; Zhou, Ye; He, Qing-Yu

    2017-10-31

    Colorectal carcinoma (CRC) remains one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the anticancer effect of Jolkinolide B (JB), a bioactive diterpenoid component isolated from the dried roots of Euphorbia fischeriana Steud, on CRC cells and its underlying mechanisms. We found that JB suppressed the cell viability and colony formation of CRC cells, HT29 and SW620. Annexin V/PI assay revealed that JB induced apoptosis in CRC cells, which was further confirmed by the increased expression of cleaved-caspase3 and cleaved-PARP. iTRAQ-based quantitative proteomics was performed to identify JB-regulated proteins in CRC cells. Gene Ontology (GO) analysis revealed that these JB-regulated proteins were mainly involved in ER stress response, which was evidenced by the expression of ER stress marker proteins, HSP90, Bip and PDI. Moreover, we found that JB provoked the generation of reactive oxygen species (ROS), and that inhibition of the ROS generation with N-acetyl L-cysteine could reverse the JB-induced apoptosis. Confocal microscopy and flow cytometry showed that JB treatment enhanced intracellular and mitochondrial Ca 2+ level and JC-1 assay revealed a loss of mitochondrial membrane potential in CRC after JB treatment. The mitochondrial Ca 2+ uptake and depolarization can be blocked by Ruthenium Red (RuRed), an inhibitor of mitochondrial Ca 2+ uniporter. Taken together, we demonstrated that JB exerts its anticancer effect by ER stress-Ca 2+ -mitochondria signaling, suggesting the promising chemotherapeutic potential of JB for the treatment of CRC.

  7. Effects of Fat and Sugar, Either Consumed or Infused toward the Brain, on Hypothalamic ER Stress Markers

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    Evita Belegri

    2017-05-01

    Full Text Available Protein-folding stress at the Endoplasmic Reticulum (ER occurs in the hypothalamus during diet-induced obesity (DIO and is linked to metabolic disease development. ER stress is buffered by the activation of the unfolded protein response (UPR, a controlled network of pathways inducing a set of genes that recovers ER function. However, it is unclear whether hypothalamic ER stress during DIO results from obesity related changes or from direct nutrient effects in the brain. We here investigated mRNA expression of UPR markers in the hypothalamus of rats that were exposed to a free choice high-fat high-sugar (fcHFHS diet for 1 week and then overnight fed ad libitum, or fasted, or fat/sugar deprived (i.e., switched from obesogenic diet to chow. In addition, we determined the direct effects of fat/sugar on mRNA expression of hypothalamus UPR markers by intracarotic infusions of intralipids and/or glucose in chow-fed rats that were fasted overnight. Short term (1 week exposure to fcHFHS diet increased adiposity compared to chow-feeding. Short term exposure to a fcHFHS diet, followed by mild food restriction overnight, induced hypothalamic ER stress in rats as characterized by an increase in spliced to unspliced X-box binding protein 1 mRNA ratio in hypothalamus of fcHFHS fed rats compared to chow fed rats. Moreover, infused lipids toward the brain of overnight fasted rats, were able to induce a similar response. Non-restricted ad libitum fcHFHS-diet fed or totally fasted rats did not show altered ratios. We also observed a clear increase in hypothalamic activating transcription factor 4 mRNA in rats on the fcHFHS diet while being ad libitum fed or when infused with intralipid via the carotic artery compared to vehicle infusions. However, we did not observe induction of downstream targets implying that this effect is a more general stress response and not related to ER stress. Overall, we conclude that the hypothalamic stress response might be a sensitive

  8. Transducer-Mounting Fixture

    Science.gov (United States)

    Spiegel, Kirk W.

    1990-01-01

    Transducer-mounting fixture holds transducer securely against stud. Projects only slightly beyond stud after installation. Flanged transducer fits into fixture when hinged halves open. When halves reclosed, fixture tightened onto threaded stud until stud makes contact with transducer. Knurled area on fixture aids in tightening fixture on stud.

  9. Signaling dynamics of palmitate-induced ER stress responses mediated by ATF4 in HepG2 cells

    Directory of Open Access Journals (Sweden)

    Cho Hyunju

    2013-01-01

    Full Text Available Abstract Background Palmitic acid, the most common saturated free fatty acid, has been implicated in ER (endoplasmic reticulum stress-mediated apoptosis. This lipoapotosis is dependent, in part, on the upregulation of the activating transcription factor-4 (ATF4. To better understand the mechanisms by which palmitate upregulates the expression level of ATF4, we integrated literature information on palmitate-induced ER stress signaling into a discrete dynamic model. The model provides an in silico framework that enables simulations and predictions. The model predictions were confirmed through further experiments in human hepatocellular carcinoma (HepG2 cells and the results were used to update the model and our current understanding of the signaling induced by palmitate. Results The three key things from the in silico simulation and experimental results are: 1 palmitate induces different signaling pathways (PKR (double-stranded RNA-activated protein kinase, PERK (PKR-like ER kinase, PKA (cyclic AMP (cAMP-dependent protein kinase A in a time dependent-manner, 2 both ATF4 and CREB1 (cAMP-responsive element-binding protein 1 interact with the Atf4 promoter to contribute to a prolonged accumulation of ATF4, and 3 CREB1 is involved in ER-stress induced apoptosis upon palmitate treatment, by regulating ATF4 expression and possibly Ca2+ dependent-CaM (calmodulin signaling pathway. Conclusion The in silico model helped to delineate the essential signaling pathways in palmitate-mediated apoptosis.

  10. Curcumin and Curcuma longa L. extract ameliorate lipid accumulation through the regulation of the endoplasmic reticulum redox and ER stress.

    Science.gov (United States)

    Lee, Hwa-Young; Kim, Seung-Wook; Lee, Geum-Hwa; Choi, Min-Kyung; Chung, Han-Wool; Lee, Yong-Chul; Kim, Hyung-Ryong; Kwon, Ho Jeong; Chae, Han-Jung

    2017-07-26

    For this study, we examined the effects of curcumin against acute and chronic stress, paying specific attention to ROS. We also aimed to clarify the differences between acute and chronic stress conditions. We investigated the effects of curcumin against acute stress (once/1 day CCl 4 treatment) and chronic-stress (every other day/4week CCl 4 treatment). Compared with acute stress, in which the antioxidant system functioned properly and aspartate transaminase (AST) and ROS production increased, chronic stress increased AST, alanine aminotransferase (ALT), hepatic enzymes, and ROS more significantly, and the antioxidant system became impaired. We also found that ER-originated ROS accumulated in the chronic model, another difference between the two conditions. ER stress was induced consistently, and oxidative intra-ER protein folding status, representatively PDI, was impaired, especially in chronic stress. The PDI-associated client protein hepatic apoB accumulated with the PDI-binding status in chronic stress, and curcumin recovered the altered ER folding status, regulating ER stress and the resultant hepatic dyslipidemia. Throughout this study, curcumin and curcumin-rich Curcuma longa L. extract promoted recovery from CCl 4 -induced hepatic toxicity in both stress conditions. For both stress-associated hepatic dyslipidemia, curcumin and Curcuma longa L. extract might be recommendable to recover liver activity.

  11. ER signaling is activated to protect human HaCaT keratinocytes from ER stress induced by environmental doses of UVB

    International Nuclear Information System (INIS)

    Mera, Kentaro; Kawahara, Ko-ichi; Tada, Ko-ichi; Kawai, Kazuhiro; Hashiguchi, Teruto; Maruyama, Ikuro; Kanekura, Takuro

    2010-01-01

    Proteins are folded properly in the endoplasmic reticulum (ER). Various stress such as hypoxia, ischemia and starvation interfere with the ER function, causing ER stress, which is defined by the accumulation of unfolded protein (UP) in the ER. ER stress is prevented by the UP response (UPR) and ER-associated degradation (ERAD). These signaling pathways are activated by three major ER molecules, ATF6, IRE-1 and PERK. Using HaCaT cells, we investigated ER signaling in human keratinocytes irradiated by environmental doses of ultraviolet B (UVB). The expression of Ero1-Lα, an upstream signaling molecule of ER stress, decreased at 1-4 h after 10 mJ/cm 2 irradiation, indicating that the environmental dose of UVB-induced ER stress in HaCaT cells, without growth retardation. Furthermore, expression of intact ATF6 was decreased and it was translocated to the nuclei. The expression of XBP-1, a downstream molecule of IRE-1, which is an ER chaperone whose expression is regulated by XBP-1, and UP ubiquitination were induced by 10 mJ/cm 2 UVB at 4 h. PERK, which regulates apoptosis, was not phosphorylated. Our results demonstrate that UVB irradiation generates UP in HaCaT cells and that the UPR and ERAD systems are activated to protect cells from UVB-induced ER stress. This is the first report to show ER signaling in UVB-irradiated keratinocytes.

  12. ER stress stimulates production of the key antimicrobial peptide, cathelicidin, by forming a previously unidentified intracellular S1P signaling complex.

    Science.gov (United States)

    Park, Kyungho; Ikushiro, Hiroko; Seo, Ho Seong; Shin, Kyong-Oh; Kim, Young Il; Kim, Jong Youl; Lee, Yong-Moon; Yano, Takato; Holleran, Walter M; Elias, Peter; Uchida, Yoshikazu

    2016-03-08

    We recently identified a previously unidentified sphingosine-1-phosphate (S1P) signaling mechanism that stimulates production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), in mammalian cells exposed to external perturbations, such as UVB irradiation and other oxidative stressors that provoke subapoptotic levels of endoplasmic reticulum (ER) stress, independent of the well-known vitamin D receptor-dependent mechanism. ER stress increases cellular ceramide and one of its distal metabolites, S1P, which activates NF-κB followed by C/EBPα activation, leading to CAMP production, but in a S1P receptor-independent fashion. We now show that S1P activates NF-κB through formation of a previously unidentified signaling complex, consisting of S1P, TRAF2, and RIP1 that further associates with three stress-responsive proteins; i.e., heat shock proteins (GRP94 and HSP90α) and IRE1α. S1P specifically interacts with the N-terminal domain of heat shock proteins. Because this ER stress-initiated mechanism is operative in both epithelial cells and macrophages, it appears to be a universal, highly conserved response, broadly protective against diverse external perturbations that lead to increased ER stress. Finally, these studies further illuminate how ER stress and S1P orchestrate critical stress-specific signals that regulate production of one protective response by stimulating production of the key innate immune element, CAMP.

  13. The CDK inhibitor p21 is a novel target gene of ATF4 and contributes to cell survival under ER stress.

    Science.gov (United States)

    Inoue, Yasumichi; Kawachi, Shiori; Ohkubo, Tsubasa; Nagasaka, Mai; Ito, Shogo; Fukuura, Keishi; Itoh, Yuka; Ohoka, Nobumichi; Morishita, Daisuke; Hayashi, Hidetoshi

    2017-11-01

    Activating transcription factor 4 (ATF4) is well known for its role in the endoplasmic reticulum (ER) stress response. ATF4 also transcriptionally induces multiple effectors that determine cell fate depending on cellular context. In addition, ATF4 can communicate both pro-apoptotic and pro-survival signals. How ATF4 mediates its prosurvival roles, however, requires further investigation. Here, we report that the CDK inhibitor p21 is a novel target gene of ATF4. We identified two ATF4-responsive elements, one of which directly binds ATF4, within the first intron of the p21 gene. Importantly, overexpression of p21 enhances cell survival following ER stress induction, while p21 knockdown increases cell death. These results suggest that p21 induction plays a vital role in the cellular response to ER stress and indicate that p21 is a prosurvival effector of ATF4. © 2017 Federation of European Biochemical Societies.

  14. Anti-Fibrotic Effect of Losartan, an Angiotensin II Receptor Blocker, Is Mediated through Inhibition of ER Stress via Up-Regulation of SIRT1, Followed by Induction of HO-1 and Thioredoxin

    Directory of Open Access Journals (Sweden)

    Hyosang Kim

    2017-01-01

    Full Text Available Endoplasmic reticulum (ER stress is increasingly identified as modulator of fibrosis. Losartan, an angiotensin II receptor blocker, has been widely used as the first choice of treatment in chronic renal diseases. We postulated that anti-fibrotic effect of losartan is mediated through inhibition of ER stress via SIRT1 (silent mating type information regulation 2 homolog 1 hemeoxygenase-1 (HO-1/thioredoxin pathway. Renal tubular cells, tunicamycin (TM-induced ER stress, and unilateral ureteral obstruction (UUO mouse model were used. Expression of ER stress was assessed by Western blot analysis and immunohistochemical stain. ER stress was induced by chemical ER stress inducer, tunicamycin, and non-chemical inducers such as TGF-β, angiotensin II, high glucose, and albumin. Losartan suppressed the TM-induced ER stress, as shown by inhibition of TM-induced expression of GRP78 (glucose related protein 78 and p-eIF2α (phosphospecific-eukaryotic translation initiation factor-2α, through up-regulation of SIRT1 via HO-1 and thioredoxin. Losartan also suppressed the ER stress by non-chemical inducers. In both animal models, losartan reduced the tubular expression of GRP78, which were abolished by pretreatment with sirtinol (SIRT1 inhibitor. Sirtinol also blocked the inhibitory effect of losartan on the UUO-induced renal fibrosis. These findings provide new insights into renoprotective effects of losartan and suggest that SIRT1, HO-1, and thioredoxin may be potential pharmacological targets in kidney diseases under excessive ER stress condition.

  15. Taurine Pretreatment Prevents Isoflurane-Induced Cognitive Impairment by Inhibiting ER Stress-Mediated Activation of Apoptosis Pathways in the Hippocampus in Aged Rats.

    Science.gov (United States)

    Zhang, Yanan; Li, Dongliang; Li, Haiou; Hou, Dailiang; Hou, Jingdong

    2016-10-01

    Isoflurane, a commonly used inhalation anesthetic, may induce neurocognitive deficits, especially in elderly patients after surgery. Recent study demonstrated that isoflurane caused endoplasmic reticulum (ER) stress and subsequent neuronal apoptosis in the brain, contributing to cognitive deficits. Taurine, a major intracellular free amino acid, has been shown to inhibit ER stress and neuronal apoptosis in several neurological disorders. Here, we examined whether taurine can prevent isoflurane-induced ER stress and cognitive impairment in aged rats. Thirty minutes prior to a 4-h 1.3 % isoflurane exposure, aged rats were treated with vehicle or taurine at low, middle and high doses. Aged rats without any treatment served as control. The brains were harvested 6 h after isoflurane exposure for molecular measurements, and behavioral study was performed 2 weeks later. Compared with control, isoflurane increased expression of hippocampal ER stress biomarkers including glucose-regulated protein 78, phosphorylated (P-) inositol-requiring enzyme 1, P-eukaryotic initiation factor 2-α (EIF2α), activating transcription factor 4 (ATF-4), cleaved ATF-6 and C/EBP homologous protein, along with activation of apoptosis pathways as indicated by decreased B cell lymphoma 2 (BCL-2)/BCL2-associated X protein, increased expressions of cytochrome-c and cleaved caspase-3. Taurine pretreatment dose-dependently inhibited isoflurane-induced increase in expression of ER stress biomarkers except for P-EIF2α and ATF-4, and reversed isoflurane-induced changes in apoptosis-related proteins. Moreover, isoflurane caused spatial working memory deficits in aged rats, which were prevented by taurine pretreatment. The results indicate that taurine pretreatment prevents anesthetic isoflurane-induced cognitive impairment by inhibiting ER stress-mediated activation of apoptosis pathways in the hippocampus in aged rats.

  16. Baicalin Ameliorates H2O2 Induced Cytotoxicity in HK-2 Cells through the Inhibition of ER Stress and the Activation of Nrf2 Signaling

    Directory of Open Access Journals (Sweden)

    Miao Lin

    2014-07-01

    Full Text Available Renal ischemia-reperfusion injury plays a key role in renal transplantation and greatly affects the outcome of allograft. Our previous study proved that Baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis, protects kidney from ischemia-reperfusion injury. This study aimed to study the underlying mechanism in vitro. Human renal proximal tubular epithelial cell line HK-2 cells were stimulated by H2O2 with and without Baicalin pretreatment. The cell viability, apoptosis and oxidative stress level were measured. The expression of endoplasmic reticulum (ER stress hallmarks, such as binding immunoglobulin protein (BiP and C/EBP homologous protein (CHOP, were analyzed by western blot and real-time PCR. NF-E2-related factor 2 (Nrf2 expression was also measured. In the H2O2 group, cell viability decreased and cell apoptosis increased. Reactive Oxygen Species (ROS and Glutathione/Oxidized Glutathione (GSH/GSSG analysis revealed increased oxidative stress. ER stress and Nrf2 signaling also increased. Baicalin pretreatment ameliorated H2O2-induced cytotoxicity, reduced oxidative stress and ER stress and further activated the anti-oxidative Nrf2 signaling pathway. The inducer of ER stress and the inhibitor of Nrf2 abrogated the protective effects, while the inhibitor of ER stress and the inducer of Nrf2 did not improve the outcome. This study revealed that Baicalin pretreatment serves a protective role against H2O2-induced cytotoxicity in HK-2 cells, where the inhibition of ER stress and the activation of downstream Nrf2 signaling are involved.

  17. Bcl-2 associated athanogene 5 (Bag5) is overexpressed in prostate cancer and inhibits ER-stress induced apoptosis

    International Nuclear Information System (INIS)

    Bruchmann, Anja; Roller, Corinna; Walther, Tamara Vanessa; Schäfer, Georg; Lehmusvaara, Sara; Visakorpi, Tapio; Klocker, Helmut; Cato, Andrew C B; Maddalo, Danilo

    2013-01-01

    The Bag (Bcl-2 associated athanogene) family of proteins consists of 6 members sharing a common, single-copied Bag domain through which they interact with the molecular chaperone Hsp70. Bag5 represents an exception in the Bag family since it consists of 5 Bag domains covering the whole protein. Bag proteins like Bag1 and Bag3 have been implicated in tumor growth and survival but it is not known whether Bag5 also exhibits this function. Bag5 mRNA and protein expression levels were investigated in prostate cancer patient samples using real-time PCR and immunoblot analyses. In addition immunohistological studies were carried out to determine the expression of Bag5 in tissue arrays. Analysis of Bag5 gene expression was carried out using one-way ANOVA and Bonferroni’s Multiple Comparison test. The mean values of the Bag5 stained cells in the tissue array was analyzed by Mann-Whitney test. Functional studies of the role of Bag5 in prostate cancer cell lines was performed using overexpression and RNA interference analyses. Our results show that Bag5 is overexpressed in malignant prostate tissue compared to benign samples. In addition we could show that Bag5 levels are increased following endoplasmic reticulum (ER)-stress induction, and Bag5 relocates from the cytoplasm to the ER during this process. We also demonstrate that Bag5 interacts with the ER-resident chaperone GRP78/BiP and enhances its ATPase activity. Bag5 overexpression in 22Rv.1 prostate cancer cells inhibited ER-stress induced apoptosis in the unfolded protein response by suppressing PERK-eIF2-ATF4 activity while enhancing the IRE1-Xbp1 axis of this pathway. Cells expressing high levels of Bag5 showed reduced sensitivity to apoptosis induced by different agents while Bag5 downregulation resulted in increased stress-induced cell death. We have therefore shown that Bag5 is overexpressed in prostate cancer and plays a role in ER-stress induced apoptosis. Furthermore we have identified GRP78/BiP as a novel

  18. Physical exercise alleviates ER stress in obese humans through reduction in the expression and release of GRP78 chaperone.

    Science.gov (United States)

    Khadir, Abdelkrim; Kavalakatt, Sina; Abubaker, Jehad; Cherian, Preethi; Madhu, Dhanya; Al-Khairi, Irina; Abu-Farha, Mohamed; Warsame, Samia; Elkum, Naser; Dehbi, Mohammed; Tiss, Ali

    2016-09-01

    Perturbation of the endoplasmic reticulum (ER) homeostasis has emerged as one of the prominent features of obesity and diabetes. This occurs when the adaptive unfolded protein response (UPR) fails to restore ER function in key metabolic tissues. We previously reported increased inflammation and impaired heat shock response (HSR) in obese human subjects that were restored by physical exercise. Here, we investigated the status of ER stress chaperone; glucose-regulated protein 78 (GRP78) and its downstream UPR pathways in human obese, and their modulation by a supervised 3-month physical exercise. Subcutaneous adipose tissue (SAT) and blood samples were collected from non-diabetic adult human lean (n=40) and obese (n=40, at baseline and after 3months of physical exercise). Transcriptomic profiling was used as a primary screen to identify differentially expressed genes and it was carried out on SAT samples using the UPR RT(2) Profiler PCR Array. Conventional RT-PCR, immunohistochemistry, immunofluorescence, Western blot and ELISA were used to validate the transcriptomic data. Correlation analyses with the physical, clinical and biochemical outcomes were performed using Pearson's rank correlation coefficient. Levels of GRP78 and its three downstream UPR arms; activating transcription factor-6 (ATF6), inositol-requiring enzyme-1α (IRE1α) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) were increased in obese subjects. More interestingly, higher levels of circulating GRP78 protein were found in obese compared to lean subjects which correlated negatively with maximum oxygen uptake (VO2 Max) but positively with high-sensitivity C-reactive protein (hsCRP) and obesity indicators such as BMI, percentage body fat (PBF) and waist circumference. GRP78 increased secretion in obese was further confirmed in vitro using 3T3-L1 preadipocyte cells under ER stress. Finally, we showed that physical exercise significantly attenuated the expression and release of GRP78

  19. Coalgebraising subsequential transducers

    NARCIS (Netherlands)

    H.H. Hansen (Helle); J. Adamek; C.A. Kupke (Clemens)

    2008-01-01

    htmlabstractSubsequential transducers generalise both classic deterministic automata and Mealy/Moore type state machines by combining (input) language recognition with transduction. In this paper we show that normalisation and taking differentials of subsequential transducers and their underlying

  20. Coalgebraising Subsequential Transducers

    NARCIS (Netherlands)

    Hansen, H.H.

    2008-01-01

    Subsequential transducers generalise both classic deterministic automata and Mealy/Moore type state machines by combining (input) language recognition with transduction. In this paper we show that normalisation and taking differentials of subsequential transducers and their underlying structures can

  1. Gliadin peptides induce tissue transglutaminase activation and ER-stress through Ca2+ mobilization in Caco-2 cells.

    Directory of Open Access Journals (Sweden)

    Ivana Caputo

    Full Text Available BACKGROUND: Celiac disease (CD is an intestinal inflammatory condition that develops in genetically susceptible individuals after exposure to dietary wheat gliadin. The role of post-translational modifications of gliadin catalyzed by tissue transglutaminase (tTG seems to play a crucial role in CD. However, it remains to be established how and where tTG is activated in vivo. We have investigated whether gliadin peptides modulate intracellular Ca(2+ homeostasis and tTG activity. METHODS/PRINCIPAL FINDINGS: We studied Ca(2+ homeostasis in Caco-2 cells by single cell microfluorimetry. Under our conditions, A-gliadin peptides 31-43 and 57-68 rapidly mobilized Ca(2+ from intracellular stores. Specifically, peptide 31-43 mobilized Ca(2+ from the endoplasmic reticulum (ER and mitochondria, whereas peptide 57-68 mobilized Ca(2+ only from mitochondria. We also found that gliadin peptide-induced Ca(2+ mobilization activates the enzymatic function of intracellular tTG as revealed by in situ tTG activity using the tTG substrate pentylamine-biotin. Moreover, we demonstrate that peptide 31-43, but not peptide 57-68, induces an increase of tTG expression. Finally, we monitored the expression of glucose-regulated protein-78 and of CCAAT/enhancer binding protein-homologous protein, which are two biochemical markers of ER-stress, by real-time RT-PCR and western blot. We found that chronic administration of peptide 31-43, but not of peptide 57-68, induces the expression of both genes. CONCLUSIONS: By inducing Ca(2+ mobilization from the ER, peptide 31-43 could promote an ER-stress pathway that may be relevant in CD pathogenesis. Furthermore, peptides 31-43 and 57-68, by activating intracellular tTG, could alter inflammatory key regulators, and induce deamidation of immunogenic peptides and gliadin-tTG crosslinking in enterocytes and specialized antigen-presenting cells.

  2. Free fatty acids induce ER stress and block antiviral activity of interferon alpha against hepatitis C virus in cell culture

    Directory of Open Access Journals (Sweden)

    Gunduz Feyza

    2012-08-01

    Full Text Available Abstract Background Hepatic steatosis is recognized as a major risk factor for liver disease progression and impaired response to interferon based therapy in chronic hepatitis C (CHC patients. The mechanism of response to interferon-alpha (IFN-α therapy under the condition of hepatic steatosis is unexplored. We investigated the effect of hepatocellular steatosis on hepatitis C virus (HCV replication and IFN-α antiviral response in a cell culture model. Methods Sub-genomic replicon (S3-GFP and HCV infected Huh-7.5 cells were cultured with a mixture of saturated (palmitate and unsaturated (oleate long-chain free fatty acids (FFA. Intracytoplasmic fat accumulation in these cells was visualized by Nile red staining and electron microscopy then quantified by microfluorometry. The effect of FFA treatment on HCV replication and IFN-α antiviral response was measured by flow cytometric analysis, Renilla luciferase activity, and real-time RT-PCR. Results FFA treatment induced dose dependent hepatocellular steatosis and lipid droplet accumulation in the HCV replicon cells was confirmed by Nile red staining, microfluorometry, and by electron microscopy. Intracellular fat accumulation supports replication more in the persistently HCV infected culture than in the sub-genomic replicon (S3-GFP cell line. FFA treatment also partially blocked IFN-α response and viral clearance by reducing the phosphorylation of Stat1 and Stat2 dependent IFN-β promoter activation. We show that FFA treatment induces endoplasmic reticulum (ER stress response and down regulates the IFNAR1 chain of the type I IFN receptor leading to defective Jak-Stat signaling and impaired antiviral response. Conclusion These results suggest that intracellular fat accumulation in HCV cell culture induces ER stress, defective Jak-Stat signaling, and attenuates the antiviral response, thus providing an explanation to the clinical observation regarding how hepatocellular steatosis influences IFN

  3. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed...

  4. Ubiquitin fold modifier 1 (UFM1 and its target UFBP1 protect pancreatic beta cells from ER stress-induced apoptosis.

    Directory of Open Access Journals (Sweden)

    Katleen Lemaire

    Full Text Available UFM1 is a member of the ubiquitin like protein family. While the enzymatic cascade of UFM1 conjugation has been elucidated in recent years, the biological function remains largely unknown. In this report we demonstrate that the recently identified C20orf116, which we name UFM1-binding protein 1 containing a PCI domain (UFBP1, and CDK5RAP3 interact with UFM1. Components of the UFM1 conjugation pathway (UFM1, UFBP1, UFL1 and CDK5RAP3 are highly expressed in pancreatic islets of Langerhans and some other secretory tissues. Co-localization of UFM1 with UFBP1 in the endoplasmic reticulum (ER depends on UFBP1. We demonstrate that ER stress, which is common in secretory cells, induces expression of Ufm1, Ufbp1 and Ufl1 in the beta-cell line INS-1E. siRNA-mediated Ufm1 or Ufbp1 knockdown enhances apoptosis upon ER stress. Silencing the E3 enzyme UFL1, results in similar outcomes, suggesting that UFM1-UFBP1 conjugation is required to prevent ER stress-induced apoptosis. Together, our data suggest that UFM1-UFBP1 participate in preventing ER stress-induced apoptosis in protein secretory cells.

  5. Evaluation of a curcumin analog as an anti-cancer agent inducing ER stress-mediated apoptosis in non-small cell lung cancer cells

    International Nuclear Information System (INIS)

    Liu, Zhiguo; Wang, Yi; Sun, Yusheng; Ren, Luqing; Huang, Yi; Cai, Yuepiao; Weng, Qiaoyou; Shen, Xueqian; Li, Xiaokun; Liang, Guang

    2013-01-01

    Recent advances have highlighted the importance of the endoplasmic reticulum (ER) in cell death processes. Pharmacological interventions that effectively enhance tumor cell death through activating ER stress have attracted a great deal of attention for anti-cancer therapy. A bio-evaluation on 113 curcumin analogs against four cancer cell lines was performed through MTT assay. Furthermore, real time cell assay and flow cytometer were used to evaluate the apoptotic induction of (1E,4E)-1,5-bis(5-bromo-2-ethoxyphenyl)penta-1,4-dien-3-one (B82). Western blot, RT-qPCR, and siRNA were then utilized to confirm whether B82-induced apoptosis is mediated through activating ER stress pathway. Finally, the in vivo anti-tumor effect of B82 was evaluated. B82 exhibited strong anti-tumor activity in non-small cell lung cancer (NSCLC) H460 cells. Treatment with B82 significantly induced apoptosis in H460 cells in vitro and inhibited H460 tumor growth in vivo. Further studies demonstrated that the B82-induced apoptosis is mediated by activating ER stress both in vitro and in vivo. A new monocarbonyl analog of curcumin, B82, exhibited anti-tumor effects on H460 cells via an ER stress-mediated mechanism. B82 could be further explored as a potential anticancer agent for the treatment of NSCLC

  6. ER Stress and Autophagic Perturbations Lead to Elevated Extracellular α-Synuclein in GBA-N370S Parkinson's iPSC-Derived Dopamine Neurons

    DEFF Research Database (Denmark)

    Fernandes, H. J. R.; Hartfield, E. M.; Christian Kjeldsen, Hans

    2016-01-01

    -derived neuronal culture medium, which was not associated with exosomes. Overall, ER stress, autophagic/lysosomal perturbations, and elevated extracellular α-synuclein likely represent critical early cellular phenotypes of PD, which might offer multiple therapeutic targets. © 2016 The Authors....

  7. Ultraviolet (UV and Hydrogen Peroxide Activate Ceramide-ER Stress-AMPK Signaling Axis to Promote Retinal Pigment Epithelium (RPE Cell Apoptosis

    Directory of Open Access Journals (Sweden)

    Jin Yao

    2013-05-01

    Full Text Available Ultraviolet (UV radiation and reactive oxygen species (ROS impair the physiological functions of retinal pigment epithelium (RPE cells by inducing cell apoptosis, which is the main cause of age-related macular degeneration (AMD. The mechanism by which UV/ROS induces RPE cell death is not fully addressed. Here, we observed the activation of a ceramide-endoplasmic reticulum (ER stress-AMP activated protein kinase (AMPK signaling axis in UV and hydrogen peroxide (H2O2-treated RPE cells. UV and H2O2 induced an early ceramide production, profound ER stress and AMPK activation. Pharmacological inhibitors against ER stress (salubrinal, ceramide production (fumonisin B1 and AMPK activation (compound C suppressed UV- and H2O2-induced RPE cell apoptosis. Conversely, cell permeable short-chain C6 ceramide and AMPK activator AICAR (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide mimicked UV and H2O2’s effects and promoted RPE cell apoptosis. Together, these results suggest that UV/H2O2 activates the ceramide-ER stress-AMPK signaling axis to promote RPE cell apoptosis.

  8. ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis

    DEFF Research Database (Denmark)

    DeZwaan-McCabe, Diane; Sheldon, Ryan D; Gorecki, Michelle C

    2017-01-01

    advantage of enhanced hepatic and renal steatosis in mice lacking the ER stress sensor ATF6α. We found that impaired fatty acid oxidation contributed to the early development of steatosis in the liver but not the kidney, while anorexia-induced lipolysis promoted late triglyceride and free fatty acid...

  9. ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis.

    Science.gov (United States)

    DeZwaan-McCabe, Diane; Sheldon, Ryan D; Gorecki, Michelle C; Guo, Deng-Fu; Gansemer, Erica R; Kaufman, Randal J; Rahmouni, Kamal; Gillum, Matthew P; Taylor, Eric B; Teesch, Lynn M; Rutkowski, D Thomas

    2017-05-30

    The unfolded protein response (UPR), induced by endoplasmic reticulum (ER) stress, regulates the expression of factors that restore protein folding homeostasis. However, in the liver and kidney, ER stress also leads to lipid accumulation, accompanied at least in the liver by transcriptional suppression of metabolic genes. The mechanisms of this accumulation, including which pathways contribute to the phenotype in each organ, are unclear. We combined gene expression profiling, biochemical assays, and untargeted lipidomics to understand the basis of stress-dependent lipid accumulation, taking advantage of enhanced hepatic and renal steatosis in mice lacking the ER stress sensor ATF6α. We found that impaired fatty acid oxidation contributed to the early development of steatosis in the liver but not the kidney, while anorexia-induced lipolysis promoted late triglyceride and free fatty acid accumulation in both organs. These findings provide evidence for both direct and indirect regulation of peripheral metabolism by ER stress. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Transducer handbook user's directory of electrical transducers

    CERN Document Server

    Boyle, H B

    2013-01-01

    When selecting or using a particular type of transducer or sensor, there are a number of factors which must be considered. The question is not only for what kind of measurement, but under what physical conditions, constraints of accuracy, and to meet which service requirements, is a transducer needed? This handbook is designed to meet the selection needs of anyone specifying or using transducers with an electrical output. Each transducer is described in an easy-to-use tabular format, giving all of the necessary data including operating principles, applications, range limits, errors, over-range protection, supply voltage requirements, sensitivities, cross sensitivities, temperature ranges and sensitivities and signal conditioning needs. The author has added notes that reflect his broad practical experience. Added to this is an extensive worldwide suppliers directory.

  11. Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying; Li, Jia; Li, Shanshan; Li, Yi; Wang, Xiangxiang; Liu, Baolin [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China); Fu, Qiang, E-mail: fuqiang@cpu.edu.cn [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China); Ma, Shiping, E-mail: spma@cpu.edu.cn [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China)

    2015-07-01

    Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult. - Highlights: • Curcumin attenuates glutamate neurotoxicity in the hippocampus. • Curcumin suppresses ER stress in glutamate-induced hippocampus slices. • Curcumin inhibits TXNIP/NLRP3 inflammasome activation. • Regulation of AMPK by curcumin contributes to suppressing ER stress.

  12. Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK

    International Nuclear Information System (INIS)

    Li, Ying; Li, Jia; Li, Shanshan; Li, Yi; Wang, Xiangxiang; Liu, Baolin; Fu, Qiang; Ma, Shiping

    2015-01-01

    Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult. - Highlights: • Curcumin attenuates glutamate neurotoxicity in the hippocampus. • Curcumin suppresses ER stress in glutamate-induced hippocampus slices. • Curcumin inhibits TXNIP/NLRP3 inflammasome activation. • Regulation of AMPK by curcumin contributes to suppressing ER stress

  13. Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

    2011-07-29

    Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  14. BDNF/TrkB Pathway Mediates the Antidepressant-Like Role of H2S in CUMS-Exposed Rats by Inhibition of Hippocampal ER Stress.

    Science.gov (United States)

    Wei, Le; Kan, Li-Yuan; Zeng, Hai-Ying; Tang, Yi-Yun; Huang, Hong-Lin; Xie, Ming; Zou, Wei; Wang, Chun-Yan; Zhang, Ping; Tang, Xiao-Qing

    2018-06-01

    Our previous works have shown that hydrogen sulfide (H 2 S) significantly attenuates chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors and hippocampal endoplasmic reticulum (ER) stress. Brain-derived neurotrophic factor (BDNF) generates an antidepressant-like effect by its receptor tyrosine protein kinase B (TrkB). We have previously found that H 2 S upregulates the expressions of BDNF and p-TrkB in the hippocampus of CUMS-exposed rats. Therefore, the present work was to explore whether BDNF/TrkB pathway mediates the antidepressant-like role of H 2 S by blocking hippocampal ER stress. We found that treatment with K252a (an inhibitor of BDNF/TrkB pathway) significantly increased the immobility time in the forced swim test and tail suspension test and increased the latency to feed in the novelty-suppressed feeding test in the rats cotreated with sodium hydrosulfide (NaHS, a donor of H 2 S) and CUMS. Similarly, K252a reversed the protective effect of NaHS against CUMS-induced hippocampal ER stress, as evidenced by increases in the levels of ER stress-related proteins, glucose-regulated protein 78, CCAAT/enhancer binding protein homologous protein and cleaved caspase-12. Taken together, our results suggest that BDNF/TrkB pathway plays an important mediatory role in the antidepressant-like action of H 2 S in CUMS-exposed rats, which is by suppression of hippocampal ER stress. These data provide a novel mechanism underlying the protection of H 2 S against CUMS-induced depressive-like behaviors.

  15. EFP1 is an ER stress-induced glycoprotein which interacts with the pro-apoptotic protein Par-4

    Directory of Open Access Journals (Sweden)

    Sarah Appel

    2009-05-01

    Full Text Available Sarah Appel1,2,6, Susanne Vetterkind1,2,6, Ansgar Koplin1,3, Barbara Maertens1,4, Meike Boosen1,5, Ute Preuss11The Institute of Genetics, University of Bonn, Bonn, Germany; 2Department of Health Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, USA; 3Center for Molecular Biology Heidelberg (ZMBH, Heidelberg, Germany; 4Institute of Biochemistry II, University of Cologne, Cologne, Germany; 5Institute of Pharmacology and Toxicology, University Hospital of Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany; 6These authors contributed equally to this work.Abstract: We have isolated the rat ortholog of EFP1 (EF-hand binding protein 1 as a novel interaction partner of the pro-apoptotic protein Par-4 (prostate apoptosis response-4. Rat EFP1 contains two thioredoxin domains, the COOH-terminal one harboring a CGFC motif, and has a similar protein domain structure as members of the protein disulfide isomerase (PDI family. In REF52.2 and CHO cells, EFP1 colocalized with the endoplasmic reticulum (ER marker PDI. Furthermore, EFP1 possesses catalytic activity as demonstrated by an insulin disulfide reduction assay. Western blot analysis revealed two EFP1 protein bands of approximately 136 and 155 kDa, representing different glycosylation states of the protein. Complex formation between EFP1 and Par-4 was confirmed in vitro and in vivo by co-immunoprecipitation, dot blot overlay and pull-down experiments. In CHO cells, coexpression of EFP1 and Par-4 resulted in enhanced Par-4-mediated apoptosis, which required the catalytic activity of EFP1. Interestingly, EFP1 was specifically upregulated in NIH3T3 cells after induction of ER stress by thapsigargin, tunicamycin, and brefeldin A, but not by agents that induce oxidative stress or ER-independent apoptosis. Furthermore, we could show that the induction of apoptosis by Ca2+ stress-inducing agents was significantly decreased after si

  16. XBP1-Independent UPR Pathways Suppress C/EBP-β Mediated Chondrocyte Differentiation in ER-Stress Related Skeletal Disease.

    Directory of Open Access Journals (Sweden)

    Trevor L Cameron

    2015-09-01

    Full Text Available Schmid metaphyseal chondrodysplasia (MCDS involves dwarfism and growth plate cartilage hypertrophic zone expansion resulting from dominant mutations in the hypertrophic zone collagen, Col10a1. Mouse models phenocopying MCDS through the expression of an exogenous misfolding protein in the endoplasmic reticulum (ER in hypertrophic chondrocytes have demonstrated the central importance of ER stress in the pathology of MCDS. The resultant unfolded protein response (UPR in affected chondrocytes involved activation of canonical ER stress sensors, IRE1, ATF6, and PERK with the downstream effect of disrupted chondrocyte differentiation. Here, we investigated the role of the highly conserved IRE1/XBP1 pathway in the pathology of MCDS. Mice with a MCDS collagen X p.N617K knock-in mutation (ColXN617K were crossed with mice in which Xbp1 was inactivated specifically in cartilage (Xbp1CartΔEx2, generating the compound mutant, C/X. The severity of dwarfism and hypertrophic zone expansion in C/X did not differ significantly from ColXN617K, revealing surprising redundancy for the IRE1/XBP1 UPR pathway in the pathology of MCDS. Transcriptomic analyses of hypertrophic zone cartilage identified differentially expressed gene cohorts in MCDS that are pathologically relevant (XBP1-independent or pathologically redundant (XBP1-dependent. XBP1-independent gene expression changes included large-scale transcriptional attenuation of genes encoding secreted proteins and disrupted differentiation from proliferative to hypertrophic chondrocytes. Moreover, these changes were consistent with disruption of C/EBP-β, a master regulator of chondrocyte differentiation, by CHOP, a transcription factor downstream of PERK that inhibits C/EBP proteins, and down-regulation of C/EBP-β transcriptional co-factors, GADD45-β and RUNX2. Thus we propose that the pathology of MCDS is underpinned by XBP1 independent UPR-induced dysregulation of C/EBP-β-mediated chondrocyte differentiation

  17. Inhibition of autophagy exerts anti-colon cancer effects via apoptosis induced by p53 activation and ER stress

    International Nuclear Information System (INIS)

    Sakitani, Kosuke; Hirata, Yoshihiro; Hikiba, Yohko; Hayakawa, Yoku; Ihara, Sozaburo; Suzuki, Hirobumi; Suzuki, Nobumi; Serizawa, Takako; Kinoshita, Hiroto; Sakamoto, Kei; Nakagawa, Hayato; Tateishi, Keisuke; Maeda, Shin; Ikenoue, Tsuneo; Kawazu, Shoji; Koike, Kazuhiko

    2015-01-01

    Although some molecularly targeted drugs for colorectal cancer are used clinically and contribute to a better prognosis, the current median survival of advanced colorectal cancer patients is not sufficient. Autophagy, a basic cell survival mechanism mediated by recycling of cellular amino acids, plays an important role in cancer. Recently, autophagy has been highlighted as a promising new molecular target. The unfolded protein response (UPR) reportedly act in complementary fashion with autophagy in intestinal homeostasis. However, the roles of UPR in colon cancer under autophagic inhibition remain to be elucidated. We aim to clarify the inhibitory effect of autophagy on colon cancer. We crossed K19 CreERT and Atg5 flox/flox mice to generate Atg5 flox/flox /K19 CreERT mice. Atg5 flox/flox /K19 CreERT mice were first treated with azoxymethane/dextran sodium sulfate and then injected with tamoxifen to inhibit autophagy in CK19-positive epithelial cells. To examine the anti-cancer mechanisms of autophagic inhibition, we used colon cancer cell lines harboring different p53 gene statuses, as well as small interfering RNAs (siRNAs) targeting Atg5 and immunoglobulin heavy-chain binding protein (BiP), a chaperone to aid folding of unfolded proteins. Colon tumors in Atg5 flox/flox /K19 CreERT mice showed loss of autophagic activity and decreased tumor size (the total tumor diameter was 28.1 mm in the control and 20.7 mm in Atg5 flox/flox /K19 CreERT mice, p = 0.036). We found that p53 and UPR/endoplasmic reticulum (ER) stress-related proteins, such as cleaved caspase 3, and CAAT/enhancer-binding protein homologous protein, are up-regulated in colon tumors of Atg5 flox/flox /K19 CreERT mice. Although Atg5 and BiP silencing, respectively, increased apoptosis in p53 wild type cells, Atg5 silencing alone did not show the same effect on apoptosis in p53 mutant cells. However, co-transfection of Atg5 and BiP siRNAs led to increased apoptosis in p53 mutant cells. Blocking autophagy

  18. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  19. Involvement of TR3/Nur77 translocation to the endoplasmic reticulum in ER stress-induced apoptosis

    International Nuclear Information System (INIS)

    Liang Bin; Song Xuhong; Liu Gefei; Li Rui; Xie Jianping; Xiao Lifeng; Du Mudan; Zhang Qiaoxia; Xu Xiaoyuan; Gan Xueqiong; Huang Dongyang

    2007-01-01

    Nuclear orphan receptor TR3/Nur77/NGFI-B is a novel apoptotic effector protein that initiates apoptosis largely by translocating from the nucleus to the mitochondria, causing the release of cytochrome c. However, it is possible that TR3 translocates to other organelles. The present study was designed to determine the intracellular localization of TR3 following CD437-induced nucleocytoplasmic translocation and the mechanisms involved in TR3-induced apoptosis. In human neuroblastoma SK-N-SH cells and human esophageal squamous carcinoma EC109 and EC9706 cells, 5 μM CD437 induced translocation of TR3 to the endoplasmic reticulum (ER). This distribution was confirmed by immunofluorescence analysis, subcellular fractionation analysis and coimmunoprecipitation analysis. The translocated TR3 interacted with ER-targeting Bcl-2; initiated an early release of Ca 2+ from ER; resulted in ER stress and induced apoptosis through ER-specific caspase-4 activation, together with induction of mitochondrial stress and subsequent activation of caspase-9. Our results identified a novel distribution of TR3 in the ER and defined two parallel mitochondrial- and ER-based pathways that ultimately result in apoptotic cell death

  20. Hypothalamic AMPK-ER Stress-JNK1 Axis Mediates the Central Actions of Thyroid Hormones on Energy Balance.

    Science.gov (United States)

    Martínez-Sánchez, Noelia; Seoane-Collazo, Patricia; Contreras, Cristina; Varela, Luis; Villarroya, Joan; Rial-Pensado, Eva; Buqué, Xabier; Aurrekoetxea, Igor; Delgado, Teresa C; Vázquez-Martínez, Rafael; González-García, Ismael; Roa, Juan; Whittle, Andrew J; Gomez-Santos, Beatriz; Velagapudi, Vidya; Tung, Y C Loraine; Morgan, Donald A; Voshol, Peter J; Martínez de Morentin, Pablo B; López-González, Tania; Liñares-Pose, Laura; Gonzalez, Francisco; Chatterjee, Krishna; Sobrino, Tomás; Medina-Gómez, Gema; Davis, Roger J; Casals, Núria; Orešič, Matej; Coll, Anthony P; Vidal-Puig, Antonio; Mittag, Jens; Tena-Sempere, Manuel; Malagón, María M; Diéguez, Carlos; Martínez-Chantar, María Luz; Aspichueta, Patricia; Rahmouni, Kamal; Nogueiras, Rubén; Sabio, Guadalupe; Villarroya, Francesc; López, Miguel

    2017-07-05

    Thyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT. The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum (ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPKα1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism. Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Hepatitis C Virus Infection Induces Autophagy as a Prosurvival Mechanism to Alleviate Hepatic ER-Stress Response

    Science.gov (United States)

    Dash, Srikanta; Chava, Srinivas; Aydin, Yucel; Chandra, Partha K.; Ferraris, Pauline; Chen, Weina; Balart, Luis A.; Wu, Tong; Garry, Robert F.

    2016-01-01

    Hepatitis C virus (HCV) infection frequently leads to chronic liver disease, liver cirrhosis and hepatocellular carcinoma (HCC). The molecular mechanisms by which HCV infection leads to chronic liver disease and HCC are not well understood. The infection cycle of HCV is initiated by the attachment and entry of virus particles into a hepatocyte. Replication of the HCV genome inside hepatocytes leads to accumulation of large amounts of viral proteins and RNA replication intermediates in the endoplasmic reticulum (ER), resulting in production of thousands of new virus particles. HCV-infected hepatocytes mount a substantial stress response. How the infected hepatocyte integrates the viral-induced stress response with chronic infection is unknown. The unfolded protein response (UPR), an ER-associated cellular transcriptional response, is activated in HCV infected hepatocytes. Over the past several years, research performed by a number of laboratories, including ours, has shown that HCV induced UPR robustly activates autophagy to sustain viral replication in the infected hepatocyte. Induction of the cellular autophagy response is required to improve survival of infected cells by inhibition of cellular apoptosis. The autophagy response also inhibits the cellular innate antiviral program that usually inhibits HCV replication. In this review, we discuss the physiological implications of the HCV-induced chronic ER-stress response in the liver disease progression. PMID:27223299

  2. Zinc Transporter SLC39A7/ZIP7 Promotes Intestinal Epithelial Self-Renewal by Resolving ER Stress

    Science.gov (United States)

    Ohashi, Wakana; Kimura, Shunsuke; Iwanaga, Toshihiko; Furusawa, Yukihiro; Irié, Tarou; Izumi, Hironori; Watanabe, Takashi; Hara, Takafumi; Ohara, Osamu; Koseki, Haruhiko; Sato, Toshiro; Robine, Sylvie; Mori, Hisashi; Hattori, Yuichi; Mishima, Kenji; Ohno, Hiroshi; Hase, Koji; Fukada, Toshiyuki

    2016-01-01

    Zinc transporters play a critical role in spatiotemporal regulation of zinc homeostasis. Although disruption of zinc homeostasis has been implicated in disorders such as intestinal inflammation and aberrant epithelial morphology, it is largely unknown which zinc transporters are responsible for the intestinal epithelial homeostasis. Here, we show that Zrt-Irt-like protein (ZIP) transporter ZIP7, which is highly expressed in the intestinal crypt, is essential for intestinal epithelial proliferation. Mice lacking Zip7 in intestinal epithelium triggered endoplasmic reticulum (ER) stress in proliferative progenitor cells, leading to significant cell death of progenitor cells. Zip7 deficiency led to the loss of Olfm4+ intestinal stem cells and the degeneration of post-mitotic Paneth cells, indicating a fundamental requirement for Zip7 in homeostatic intestinal regeneration. Taken together, these findings provide evidence for the importance of ZIP7 in maintenance of intestinal epithelial homeostasis through the regulation of ER function in proliferative progenitor cells and maintenance of intestinal stem cells. Therapeutic targeting of ZIP7 could lead to effective treatment of gastrointestinal disorders. PMID:27736879

  3. Zinc Transporter SLC39A7/ZIP7 Promotes Intestinal Epithelial Self-Renewal by Resolving ER Stress.

    Directory of Open Access Journals (Sweden)

    Wakana Ohashi

    2016-10-01

    Full Text Available Zinc transporters play a critical role in spatiotemporal regulation of zinc homeostasis. Although disruption of zinc homeostasis has been implicated in disorders such as intestinal inflammation and aberrant epithelial morphology, it is largely unknown which zinc transporters are responsible for the intestinal epithelial homeostasis. Here, we show that Zrt-Irt-like protein (ZIP transporter ZIP7, which is highly expressed in the intestinal crypt, is essential for intestinal epithelial proliferation. Mice lacking Zip7 in intestinal epithelium triggered endoplasmic reticulum (ER stress in proliferative progenitor cells, leading to significant cell death of progenitor cells. Zip7 deficiency led to the loss of Olfm4+ intestinal stem cells and the degeneration of post-mitotic Paneth cells, indicating a fundamental requirement for Zip7 in homeostatic intestinal regeneration. Taken together, these findings provide evidence for the importance of ZIP7 in maintenance of intestinal epithelial homeostasis through the regulation of ER function in proliferative progenitor cells and maintenance of intestinal stem cells. Therapeutic targeting of ZIP7 could lead to effective treatment of gastrointestinal disorders.

  4. ER stress inducer tunicamycin suppresses the self-renewal of glioma-initiating cell partly through inhibiting Sox2 translation.

    Science.gov (United States)

    Xing, Yang; Ge, Yuqing; Liu, Chanjuan; Zhang, Xiaobiao; Jiang, Jianhai; Wei, Yuanyan

    2016-06-14

    Glioma-initiating cells possess tumor-initiating potential and are relatively resistant to conventional chemotherapy and irradiation. Therefore, their elimination is an essential factor for the development of efficient therapy. Here, we report that endoplasmic reticulum (ER) stress inducer tunicamycin inhibits glioma-initiating cell self-renewal as determined by neurosphere formation assay. Moreover, tunicamycin decreases the efficiency of glioma-initiating cell to initiate tumor formation. Although tunicamycin induces glioma-initiating cell apoptosis, apoptosis inhibitor z-VAD-fmk only partly abrogates the reduction in glioma-initiating cell self-renewal induced by tunicamycin. Indeed, tunicamycin reduces the expression of self-renewal regulator Sox2 at translation level. Overexpression of Sox2 obviously abrogates the reduction in glioma-initiating cell self-renewal induced by tunicamycin. Taken together, tunicamycin suppresses the self-renewal and tumorigenic potential of glioma-initiating cell partly through reducing Sox2 translation. This finding provides a cue to potential effective treatment of glioblastoma through controlling stem cells.

  5. Periodontal disease level-butyric acid amounts locally administered in the rat gingival mucosa induce ER stress in the systemic blood.

    Science.gov (United States)

    Cueno, Marni E; Saito, Yuko; Ochiai, Kuniyasu

    2016-05-01

    Periodontal diseases have long been postulated to contribute to systemic diseases and, likewise, it has been proposed that periodontal disease treatment may ameliorate certain systemic diseases. Short-chain fatty acids (SCFA) are major secondary metabolites produced by oral anaerobic bacteria and, among the SCFAs, butyric acid (BA) in high amounts contribute to periodontal disease development. Periodontal disease level-butyric acid (PDL-BA) is found among patients suffering from periodontal disease and has previously shown to induce oxidative stress, whereas, oxidative stress is correlated to endoplasmic reticulum (ER) stress. This would imply that PDL-BA may likewise stimulate ER stress, however, this was never elucidated. A better understanding of the correlation between PDL-BA and systemic ER stress stimulation could shed light on the possible systemic effects of PDL-BA-related periodontal diseases. Here, PDL-BA was injected into the gingival mucosa and the systemic blood obtained from the rat jugular was collected at 0, 15, 60, and 180 min post-injection. Collected blood samples were purified and only the blood cytosol was used throughout this study. Subsequently, we measured blood cytosolic GADD153, Ca(2+), representative apoptotic and inflammatory caspases, and NF-κB amounts. We found that PDL-BA presence increased blood cytosolic GADD153 and Ca(2+) amounts. Moreover, we observed that blood cytosolic caspases and NF-κB were activated only at 60 and 180 min post-injection in the rat gingival mucosa. This suggests that PDL-BA administered through the gingival mucosa may influence the systemic blood via ER stress stimulation and, moreover, prolonged PDL-BA retention in the gingival mucosa may play a significant role in ER stress-related caspase and NF-κB activation. In a periodontal disease scenario, we propose that PDL-BA-related ER stress stimulation leading to the simultaneous activation of apoptosis and inflammation may contribute to periodontal disease

  6. Curcumin abates hypoxia-induced oxidative stress based-ER stress-mediated cell death in mouse hippocampal cells (HT22) by controlling Prdx6 and NF-κB regulation

    Science.gov (United States)

    Chhunchha, Bhavana; Fatma, Nigar; Kubo, Eri; Rai, Prerana; Singh, Sanjay P.

    2013-01-01

    Oxidative stress and endoplasmic reticulum (ER) stress are emerging as crucial events in the etiopathology of many neurodegenerative diseases. While the neuroprotective contributions of the dietary compound curcumin has been recognized, the molecular mechanisms underlying curcumin's neuroprotection under oxidative and ER stresses remains elusive. Herein, we show that curcumin protects HT22 from oxidative and ER stresses evoked by the hypoxia (1% O2 or CoCl2 treatment) by enhancing peroxiredoxin 6 (Prdx6) expression. Cells exposed to CoCl2 displayed reduced expression of Prdx6 with higher reactive oxygen species (ROS) expression and activation of NF-κB with IκB phosphorylation. When NF-κB activity was blocked by using SN50, an inhibitor of NF-κB, or cells treated with curcumin, the repression of Prdx6 expression was restored, suggesting the involvement of NF-κB in modulating Prdx6 expression. These cells were enriched with an accumulation of ER stress proteins, C/EBP homologous protein (CHOP), GRP/78, and calreticulin, and had activated states of caspases 12, 9, and 3. Reinforced expression of Prdx6 in HT22 cells by curcumin reestablished survival signaling by reducing propagation of ROS and blunting ER stress signaling. Intriguingly, knockdown of Prdx6 by antisense revealed that loss of Prdx6 contributed to cell death by sustaining enhanced levels of ER stress-responsive proapoptotic proteins, which was due to elevated ROS production, suggesting that Prdx6 deficiency is a cause of initiation of ROS-mediated ER stress-induced apoptosis. We propose that using curcumin to reinforce the naturally occurring Prdx6 expression and attenuate ROS-based ER stress and NF-κB-mediated aberrant signaling improves cell survival and may provide an avenue to treat and/or postpone diseases associated with ROS or ER stress. PMID:23364261

  7. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...

  8. Crossflow force transducer

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1982-05-01

    A force transducer for measuring lift and drag coefficients for a circular cylinder in turbulent water flow is presented. In addition to describing the actual design and construction of the strain-gauged force- ring based transducer, requirements for obtained valid fluid force test data are discussed, and pertinent flow test experience is related

  9. Modeling of ultrasound transducers

    DEFF Research Database (Denmark)

    Bæk, David

    This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...... (REFT) and to a convex rectangular elevation focused transducer (CREFT). These models are solvable on an analog time scale and give exact smooth solutions to the Rayleigh integral. The REFT model exhibits a root mean square (RMS) error relative to Field II predictions of 0.41 % at 3400 MHz, and 1.......37 % at 100MHz. The CREFT model exhibits a RMS deviation of 0.01 % relative to the exact numerical solution on a CREFT transducer. A convex non-elevation focused, a REFT, and a linear flat transducer are shown to be covered with the CREFT model as well. Pressure pulses calculated with a one...

  10. Bilirubin Increases Insulin Sensitivity in Leptin-Receptor Deficient and Diet-Induced Obese Mice Through Suppression of ER Stress and Chronic Inflammation

    Science.gov (United States)

    Dong, Huansheng; Huang, Hu; Yun, Xinxu; Kim, Do-sung; Yue, Yinan; Wu, Hongju; Sutter, Alton; Chavin, Kenneth D.; Otterbein, Leo E.; Adams, David B.; Kim, Young-Bum

    2014-01-01

    Obesity-induced endoplasmic reticulum (ER) stress causes chronic inflammation in adipose tissue and steatosis in the liver, and eventually leads to insulin resistance and type 2 diabetes (T2D). The goal of this study was to understand the mechanisms by which administration of bilirubin, a powerful antioxidant, reduces hyperglycemia and ameliorates obesity in leptin-receptor-deficient (db/db) and diet-induced obese (DIO) mouse models. db/db or DIO mice were injected with bilirubin or vehicle ip. Blood glucose and body weight were measured. Activation of insulin-signaling pathways, expression of inflammatory cytokines, and ER stress markers were measured in skeletal muscle, adipose tissue, and liver of mice. Bilirubin administration significantly reduced hyperglycemia and increased insulin sensitivity in db/db mice. Bilirubin treatment increased protein kinase B (PKB/Akt) phosphorylation in skeletal muscle and suppressed expression of ER stress markers, including the 78-kDa glucose-regulated protein (GRP78), CCAAT/enhancer-binding protein (C/EBP) homologous protein, X box binding protein (XBP-1), and activating transcription factor 4 in db/db mice. In DIO mice, bilirubin treatment significantly reduced body weight and increased insulin sensitivity. Moreover, bilirubin suppressed macrophage infiltration and proinflammatory cytokine expression, including TNF-α, IL-1β, and monocyte chemoattractant protein-1, in adipose tissue. In liver and adipose tissue of DIO mice, bilirubin ameliorated hepatic steatosis and reduced expression of GRP78 and C/EBP homologous protein. These results demonstrate that bilirubin administration improves hyperglycemia and obesity by increasing insulin sensitivity in both genetically engineered and DIO mice models. Bilirubin or bilirubin-increasing drugs might be useful as an insulin sensitizer for the treatment of obesity-induced insulin resistance and type 2 diabetes based on its profound anti-ER stress and antiinflammatory properties. PMID

  11. The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication.

    Science.gov (United States)

    Hazman, Ömer; Bozkurt, Mehmet Fatih; Fidan, Abdurrahman Fatih; Uysal, Fadime Erkan; Çelik, Sefa

    2018-03-02

    The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.

  12. Role of silent information regulator 1 in the protective effect of hydrogen sulfide on homocysteine-induced cognitive dysfunction: Involving reduction of hippocampal ER stress.

    Science.gov (United States)

    Tang, Yi-Yun; Wang, Ai-Ping; Wei, Hai-Jun; Li, Man-Hong; Zou, Wei; Li, Xiang; Wang, Chun-Yan; Zhang, Ping; Tang, Xiao-Qing

    2018-04-16

    Homocysteine (Hcy) causes cognitive deficits and hippocampal endoplasmic reticulum (ER) stress. Our previous study has confirmed that Hydrogen sulfide (H 2 S) attenuates Hcy-induced cognitive dysfunction and hippocampal ER stress. Silent information regulator 1 (Sirt-1) is indispensable in the formation of learning and memory. Therefore, the aim of this study was to explore the role of Sirt-1 in the protective effect of H 2 S against Hcy-induced cognitive dysfunction. We found that NaHS (a donor of H 2 S) markedly up-regulated the expression of Sirt-1 in the hippocampus of Hcy-exposed rats. Sirtinol, a specific inhibitor of Sirt-1, reversed the improving role of NaHS in the cognitive function of Hcy-exposed rats, as evidenced by that sirtinol increased the escape latency and the swim distance in the acquisition trial of morris water maze (MWM) test, decreased the times crossed through and the time spent in the target quadrant in the probe trail of MWM test, and reduced the discrimination index in the novel object recognition test (NORT) in the rats cotreated with NaHS and Hcy. We also found that sirtinol reversed the protection of NaHS against Hcy-induced hippocampal ER-stress, as evidenced by up-regulating the expressions of GRP78, CHOP, and cleaved caspase-12 in the hippocampus of rats cotreated with NaHS and Hcy. These results suggested the contribution of upregulation of hippocampal Sirt-1 to the improving role of H 2 S in the cognitive function of Hcy-exposed rats, which involves suppression of hippocampal ER stress. Our finding provides a new insight into the mechanism underlying the inhibitory role of H 2 S in Hcy-induced cognitive dysfunction. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. The novel white spot syndrome virus-induced gene, PmERP15, encodes an ER stress-responsive protein in black tiger shrimp, Penaeus monodon.

    Science.gov (United States)

    Leu, Jiann-Horng; Liu, Kuan-Fu; Chen, Kuan-Yu; Chen, Shu-Hwa; Wang, Yu-Bin; Lin, Chung-Yen; Lo, Chu-Fang

    2015-04-01

    By microarray screening, we identified a white spot syndrome virus (WSSV)-strongly induced novel gene in gills of Penaeus monodon. The gene, PmERP15, encodes a putative transmembrane protein of 15 kDa, which only showed some degree of similarity (54-59%) to several unknown insect proteins, but had no hits to shrimp proteins. RT-PCR showed that PmERP15 was highly expressed in the hemocytes, heart and lymphoid organs, and that WSSV-induced strong expression of PmERP15 was evident in all tissues examined. Western blot analysis likewise showed that WSSV strongly up-regulated PmERP15 protein levels. In WSSV-infected hemocytes, immunofluorescence staining showed that PmERP15 protein was colocalized with an ER enzyme, protein disulfide isomerase, and in Sf9 insect cells, PmERP15-EGFP fusion protein colocalized with ER -Tracker™ Red dye as well. GRP78, an ER stress marker, was found to be up-regulated in WSSV-infected P. monodon, and both PmERP15 and GRP78 were up-regulated in shrimp injected with ER stress inducers tunicamycin and dithiothreitol. Silencing experiments showed that although PmERP15 dsRNA-injected shrimp succumbed to WSSV infection more rapidly, the WSSV copy number had no significant changes. These results suggest that PmERP15 is an ER stress-induced, ER resident protein, and its induction in WSSV-infected shrimp is caused by the ER stress triggered by WSSV infection. Furthermore, although PmERP15 has no role in WSSV multiplication, its presence is essential for the survival of WSSV-infected shrimp. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. An inducer of VGF protects cells against ER stress-induced cell death and prolongs survival in the mutant SOD1 animal models of familial ALS.

    Directory of Open Access Journals (Sweden)

    Masamitsu Shimazawa

    2010-12-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is the most frequent adult-onset motor neuron disease, and recent evidence has suggested that endoplasmic reticulum (ER stress signaling is involved in the pathogenesis of ALS. Here we identified a small molecule, SUN N8075, which has a marked protective effect on ER stress-induced cell death, in an in vitro cell-based screening, and its protective mechanism was mediated by an induction of VGF nerve growth factor inducible (VGF: VGF knockdown with siRNA completely abolished the protective effect of SUN N8075 against ER-induced cell death, and overexpression of VGF inhibited ER-stress-induced cell death. VGF level was lower in the spinal cords of sporadic ALS patients than in the control patients. Furthermore, SUN N8075 slowed disease progression and prolonged survival in mutant SOD1 transgenic mouse and rat models of ALS, preventing the decrease of VGF expression in the spinal cords of ALS mice. These data suggest that VGF plays a critical role in motor neuron survival and may be a potential new therapeutic target for ALS, and SUN N8075 may become a potential therapeutic candidate for treatment of ALS.

  15. Identification of Toyocamycin, an agent cytotoxic for multiple myeloma cells, as a potent inhibitor of ER stress-induced XBP1 mRNA splicing

    International Nuclear Information System (INIS)

    Ri, M; Tashiro, E; Oikawa, D; Shinjo, S; Tokuda, M; Yokouchi, Y; Narita, T; Masaki, A; Ito, A; Ding, J; Kusumoto, S; Ishida, T; Komatsu, H; Shiotsu, Y; Ueda, R; Iwawaki, T; Imoto, M; Iida, S

    2012-01-01

    The IRE1α-XBP1 pathway, a key component of the endoplasmic reticulum (ER) stress response, is considered to be a critical regulator for survival of multiple myeloma (MM) cells. Therefore, the availability of small-molecule inhibitors targeting this pathway would offer a new chemotherapeutic strategy for MM. Here, we screened small-molecule inhibitors of ER stress-induced XBP1 activation, and identified toyocamycin from a culture broth of an Actinomycete strain. Toyocamycin was shown to suppress thapsigargin-, tunicamycin- and 2-deoxyglucose-induced XBP1 mRNA splicing in HeLa cells without affecting activating transcription factor 6 (ATF6) and PKR-like ER kinase (PERK) activation. Furthermore, although toyocamycin was unable to inhibit IRE1α phosphorylation, it prevented IRE1α-induced XBP1 mRNA cleavage in vitro. Thus, toyocamycin is an inhibitor of IRE1α-induced XBP1 mRNA cleavage. Toyocamycin inhibited not only ER stress-induced but also constitutive activation of XBP1 expression in MM lines as well as primary samples from patients. It showed synergistic effects with bortezomib, and induced apoptosis of MM cells including bortezomib-resistant cells at nanomolar levels in a dose-dependent manner. It also inhibited growth of xenografts in an in vivo model of human MM. Taken together, our results suggest toyocamycin as a lead compound for developing anti-MM therapy and XBP1 as an appropriate molecular target for anti-MM therapy

  16. The effect of glucose concentration and sodium phenylbutyrate treatment on mitochondrial bioenergetics and ER stress in 3T3-L1 adipocytes.

    Science.gov (United States)

    Tanis, Ross M; Piroli, Gerardo G; Day, Stani D; Frizzell, Norma

    2015-01-01

    While the 3T3-L1 adipocyte model is routinely used for the study of obesity and diabetes, the mitochondrial respiratory profile in normal versus high glucose has not been examined in detail. We matured adipocytes in normal (5mM) or high (30 mM) glucose and insulin and examined the mitochondrial bioenergetics. We also assessed the requirement for the Unfolded Protein Response (UPR) and ER stress under these conditions. Basal respiration was ~1.7-fold greater in adipocytes that had matured in 30 mM glucose; however, their ability to increase oxygen consumption in response to stress was impaired. Adipogenesis proceeded in both normal and high glucose with concomitant activation of the UPR, but only high glucose was associated with increased levels of ER stress and mitochondrial stress as observed by parallel increases in CHOP and protein succination. Treatment of adipocytes with sodium phenylbutyrate relieved mitochondrial stress through a reduction in mitochondrial respiration. Our data suggests that mitochondrial stress, protein succination and ER stress are uniquely linked in adipocytes matured in high glucose. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Palmitate-induced ER stress increases trastuzumab sensitivity in HER2/neu-positive breast cancer cells

    International Nuclear Information System (INIS)

    Baumann, Jan; Wong, Jason; Sun, Yan; Conklin, Douglas S.

    2016-01-01

    CHOP-dependent apoptosis as well as a partial activation of the ER stress response network via XBP1 and ATF6. This response appears to be a general feature of HER2/neu-positive breast cancer cells but not cells that overexpress only HER2/neu. Exogenous palmitate reduces HER2 and HER3 protein levels without changes in phosphorylation and sensitizes HER2/neu-positive breast cancer cells to treatment with the HER2-targeted therapy trastuzumab. Several studies have shown that HER2, FASN and fatty acid synthesis are functionally linked. Exogenous palmitate exerts its toxic effects in part through inducing ER stress, reducing HER2 expression and thereby sensitizing cells to trastuzumab. These data provide further evidence that HER2 signaling and fatty acid metabolism are highly integrated processes that may be important for disease development and progression. The online version of this article (doi:10.1186/s12885-016-2611-8) contains supplementary material, which is available to authorized users

  18. Valsartan reduces AT1-AA-induced apoptosis through suppression oxidative stress mediated ER stress in endothelial progenitor cells.

    Science.gov (United States)

    Wang, Z-C; Qi, J; Liu, L-M; Li, J; Xu, H-Y; Liang, B; Li, B

    2017-03-01

    Valsartan has been reported to have the function of treating hypertension and improving the prognosis of patients. Many studies indicated that valsartan can also increase angiotensin II, andosterone and plasma renin activity (PRA). Autoantibodies against the angiotensin II type 1 receptor (AT1-AA) have been showed to increase reactive oxygen species (ROS) and calcium (Ca2+) and result in apoptosis in vascular smooth muscle cells. In this study, we attempted to explore the effect of valsartan on AT1-AA-induced apoptosis in endothelial progenitor cells. Endothelial progenitor cells (EPCs) were cultured. The cytotoxicity was determined by MTT assay. EPCs apoptosis was determined by DAPI staining and flow cytometry. Reactive oxygen species, intracellular calcium concentration and calpain activity were measured using Fluostar Omega Spectrofluorimeter. The expression of p-ERK, p-eIF-2a, CHOP, Bcl-2 and caspase-3 were detected by Western blot. MTT assays showed valsartan significantly inhibited AT1-AA- induced decline of the viability of EPCs. DAPI staining and flow cytometry results indicated valsartan inhibited AT1-AA-induced decline of the viability of EPCs via inhibiting AT1-AA-induced apoptosis. Furthermore, the increasing of reactive oxygen species, intracellular calcium and calpain activity induced by AT1-AA in EPCs were also recovered after pre-treated with valsartan. Meanwhile, the upregulation of p-ERK, p-eIF-2a and CHOP, downregulation of Bcl-2, and activation of Caspase-3 caused by AT1-AA were reversed after pre-incubated with valsartan. Valsartan could inhibit AT1-AA-induced apoptosis through inhibiting oxidative stress mediated ER stress in EPCs.

  19. SCS3 and YFT2 link transcription of phospholipid biosynthetic genes to ER stress and the UPR.

    Directory of Open Access Journals (Sweden)

    Robyn D Moir

    2012-08-01

    Full Text Available The ability to store nutrients in lipid droplets (LDs is an ancient function that provides the primary source of metabolic energy during periods of nutrient insufficiency and between meals. The Fat storage-Inducing Transmembrane (FIT proteins are conserved ER-resident proteins that facilitate fat storage by partitioning energy-rich triglycerides into LDs. FIT2, the ancient ortholog of the FIT gene family first identified in mammals has two homologs in Saccharomyces cerevisiae (SCS3 and YFT2 and other fungi of the Saccharomycotina lineage. Despite the coevolution of these genes for more than 170 million years and their divergence from higher eukaryotes, SCS3, YFT2, and the human FIT2 gene retain some common functions: expression of the yeast genes in a human embryonic kidney cell line promotes LD formation, and expression of human FIT2 in yeast rescues the inositol auxotrophy and chemical and genetic phenotypes of strains lacking SCS3. To better understand the function of SCS3 and YFT2, we investigated the chemical sensitivities of strains deleted for either or both genes and identified synthetic genetic interactions against the viable yeast gene-deletion collection. We show that SCS3 and YFT2 have shared and unique functions that connect major biosynthetic processes critical for cell growth. These include lipid metabolism, vesicular trafficking, transcription of phospholipid biosynthetic genes, and protein synthesis. The genetic data indicate that optimal strain fitness requires a balance between phospholipid synthesis and protein synthesis and that deletion of SCS3 and YFT2 impacts a regulatory mechanism that coordinates these processes. Part of this mechanism involves a role for SCS3 in communicating changes in the ER (e.g. due to low inositol to Opi1-regulated transcription of phospholipid biosynthetic genes. We conclude that SCS3 and YFT2 are required for normal ER membrane biosynthesis in response to perturbations in lipid metabolism and ER

  20. Urotensin II Induces ER Stress and EMT and Increase Extracellular Matrix Production in Renal Tubular Epithelial Cell in Early Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Xin-Xin Pang

    2016-07-01

    Full Text Available Background/Aims: Urotensin II (UII and its receptor are highly expressed in the kidney tissue of patients with diabetic nephropathy (DN. The aim of this study is to examine the roles of UII in the induction of endoplasmic reticulum stress (ER stress and Epithelial-mesenchymal transition (EMT in DN in vivo and in vitro. Methods: Kidney tissues were collected from patients with DN. C57BL/6 mice and mice with UII receptor knock out were injected with two consecutive doses of streptozotocin to induce diabetes and were sacrificed at 3th week for in vivo study. HK-2 cells in vitro were cultured and treated with UII. Markers of ER stress and EMT, fibronectin and type IV collagen were detected by immunohistochemistry, real time PCR and western blot. Results: We found that the expressions of protein of UII, GRP78, CHOP, ALPHA-SMA, fibronectin and type IV collagen were upregulated while E-cadherin protein was downregulated as shown by immunohistochemistry or western blot analysis in kidney of diabetic mice in comparison to normal control; moreover expressions of GRP78, CHOP, ALPHA-SMA, fibronectin and type IV collagen were inhibited while E-caherin expression was enhanced in kidney in diabetic mice with UII receptor knock out in comparison to C57BL/6 diabetic mice. In HK-2 cells, UII induced upregulation of GRP78, CHOP, ALPHA-SMA, fibroblast-specifc protein 1(FSP-1, fibronectin and type collagen and downregulation of E-cadherin. UII receptor antagonist can block UII-induced ER stress and EMT; moreover, 4-PBA can inhibit the mRNA expression of ALPHA-SMA and FSP1 induced by UII in HK-2 cells. Conclusions: We are the first to verify UII induces ER stress and EMT and increase extracellular matrix production in renal tubular epithelial cell in early diabetic mice. Moreover, UII may induce renal tubular epithelial EMT via triggering ER stress pathway in vitro, which might be the new pathogenic pathway for the development of renal fibrosis in DN.

  1. Role of an ER stress response element in regulating the bidirectional promoter of the mouse CRELD2 - ALG12 gene pair

    Directory of Open Access Journals (Sweden)

    Hirata Yoko

    2010-11-01

    Full Text Available Abstract Background Recently, we identified cysteine-rich with EGF-like domains 2 (CRELD2 as a novel endoplasmic reticulum (ER stress-inducible gene and characterized its transcriptional regulation by ATF6 under ER stress conditions. Interestingly, the CRELD2 and asparagine-linked glycosylation 12 homolog (ALG12 genes are arranged as a bidirectional (head-to-head gene pair and are separated by less than 400 bp. In this study, we characterized the transcriptional regulation of the mouse CRELD2 and ALG12 genes that is mediated by a common bidirectional promoter. Results This short intergenic region contains an ER stress response element (ERSE sequence and is well conserved among the human, rat and mouse genomes. Microarray analysis revealed that CRELD2 and ALG12 mRNAs were induced in Neuro2a cells by treatment with thapsigargin (Tg, an ER stress inducer, in a time-dependent manner. Other ER stress inducers, tunicamycin and brefeldin A, also increased the expression of these two mRNAs in Neuro2a cells. We then tested for the possible involvement of the ERSE motif and other regulatory sites of the intergenic region in the transcriptional regulation of the mouse CRELD2 and ALG12 genes by using variants of the bidirectional reporter construct. With regards to the promoter activities of the CRELD2-ALG12 gene pair, the entire intergenic region hardly responded to Tg, whereas the CRELD2 promoter constructs of the proximal region containing the ERSE motif showed a marked responsiveness to Tg. The same ERSE motif of ALG12 gene in the opposite direction was less responsive to Tg. The direction and the distance of this motif from each transcriptional start site, however, has no impact on the responsiveness of either gene to Tg treatment. Additionally, we found three putative sequences in the intergenic region that antagonize the ERSE-mediated transcriptional activation. Conclusions These results show that the mouse CRELD2 and ALG12 genes are arranged as a

  2. Smart transducer with radiomodem

    Science.gov (United States)

    Pugach, V. N.; Voronin, E. L.

    2018-04-01

    Systems for measuring different parameters enabling metering and wireless data transmission are an urgent problem in the industry. One of the most promising solutions is the developments of metering instruments enabling radio-link and GSM data transmission. The article describes a transducer operating with temperature sensors of different types as well as with the sensors of other physical values with the output signal represented as current or voltage with subsequent measurement data transmission from the transducer to the computer via radio-link. The article provides transducer measurement accuracy check. The work confirmed the claimed temperature measurement accuracy, noted a stable data transmission via radio link and convenience of work with the transducer and software.

  3. UPR transducer BBF2H7 allows export of type II collagen in a cargo- and developmental stage–specific manner

    Science.gov (United States)

    Toyama, Takuya; Nakamura, Yuki; Tamada, Kentaro; Shimizu, Hitomi; Ninagawa, Satoshi; Okada, Tetsuya; Ishikawa-Fujiwara, Tomoko; Aoyama, Eriko; Takigawa, Masaharu

    2017-01-01

    The unfolded protein response (UPR) handles unfolded/misfolded proteins accumulated in the endoplasmic reticulum (ER). However, it is unclear how vertebrates correctly use the total of ten UPR transducers. We have found that ER stress occurs physiologically during early embryonic development in medaka fish and that the smooth alignment of notochord cells requires ATF6 as a UPR transducer, which induces ER chaperones for folding of type VIII (short-chain) collagen. After secretion of hedgehog for tissue patterning, notochord cells differentiate into sheath cells, which synthesize type II collagen. In this study, we show that this vacuolization step requires both ATF6 and BBF2H7 as UPR transducers and that BBF2H7 regulates a complete set of genes (Sec23/24/13/31, Tango1, Sedlin, and KLHL12) essential for the enlargement of COPII vesicles to accommodate long-chain collagen for export, leading to the formation of the perinotochordal basement membrane. Thus, the most appropriate UPR transducer is activated to cope with the differing physiological ER stresses of different content types depending on developmental stage. PMID:28500182

  4. Calibration of acoustic emission transducers

    International Nuclear Information System (INIS)

    Leschek, W.C.

    1976-01-01

    A method is described for calibrating an acoustic emission transducer to be used in a pre-set frequency range. The absolute reception sensitivity of a reference transducer is determined at frequencies selected within the frequency range. The reference transducer and the acoustic emission transducer are put into acoustic communication with the surface of a limited acoustic medium representing an equivalent acoustic load appreciably identical to that of the medium in which the use of the acoustic emission transducer is intended. A blank random acoustic noise is emitted in the acoustic medium in order to establish a diffuse and reverberating sound field, after which the output responses of the reference transducer and of the acoustic emission transducer are obtained with respect to the diffuse and reverberating field, for selected frequencies. The output response of the acoustic emission transducer is compared with that of the reference transducer for the selected frequencies, so as to determine the reception sensitivity of the acoustic emission transducer [fr

  5. Curcumin analog WZ35 induced cell death via ROS-dependent ER stress and G2/M cell cycle arrest in human prostate cancer cells

    International Nuclear Information System (INIS)

    Zhang, Xiuhua; Chen, Minxiao; Zou, Peng; Kanchana, Karvannan; Weng, Qiaoyou; Chen, Wenbo; Zhong, Peng; Ji, Jiansong; Zhou, Huiping; He, Langchong; Liang, Guang

    2015-01-01

    Prostate cancer is the most commonly diagnosed malignancy among men. The Discovery of new agents for the treatment of prostate cancer is urgently needed. Compound WZ35, a novel analog of the natural product curcumin, exhibited good anti-prostate cancer activity, with an IC 50 of 2.2 μM in PC-3 cells. However, the underlying mechanism of WZ35 against prostate cancer cells is still unclear. Human prostate cancer PC-3 cells and DU145 cells were treated with WZ35 for further proliferation, apoptosis, cell cycle, and mechanism analyses. NAC and CHOP siRNA were used to validate the role of ROS and ER stress, respectively, in the anti-cancer actions of WZ35. Our results show that WZ35 exhibited much higher cell growth inhibition than curcumin by inducing ER stress-dependent cell apoptosis in human prostate cells. The reduction of CHOP expression by siRNA partially abrogated WZ35-induced cell apoptosis. WZ35 also dose-dependently induced cell cycle arrest in the G2/M phase. Furthermore, we found that WZ35 treatment for 30 min significantly induced reactive oxygen species (ROS) production in PC-3 cells. Co-treatment with the ROS scavenger NAC completely abrogated the induction of WZ35 on cell apoptosis, ER stress activation, and cell cycle arrest, indicating an upstream role of ROS generation in mediating the anti-cancer effect of WZ35. Taken together, this work presents the novel anticancer candidate WZ35 for the treatment of prostate cancer, and importantly, reveals that increased ROS generation might be an effective strategy in human prostate cancer treatment. The online version of this article (doi:10.1186/s12885-015-1851-3) contains supplementary material, which is available to authorized users

  6. Lack of TXNIP protects against mitochondria-mediated apoptosis but not against fatty acid-induced ER stress-mediated beta-cell death.

    Science.gov (United States)

    Chen, Junqin; Fontes, Ghislaine; Saxena, Geetu; Poitout, Vincent; Shalev, Anath

    2010-02-01

    We have previously shown that lack of thioredoxin-interacting protein (TXNIP) protects against diabetes and glucotoxicity-induced beta-cell apoptosis. Because the role of TXNIP in lipotoxicity is unknown, the goal of the present study was to determine whether TXNIP expression is regulated by fatty acids and whether TXNIP deficiency also protects beta-cells against lipoapoptosis. RESARCH DESIGN AND METHODS: To determine the effects of fatty acids on beta-cell TXNIP expression, INS-1 cells and isolated islets were incubated with/without palmitate and rats underwent cyclic infusions of glucose and/or Intralipid prior to islet isolation and analysis by quantitative real-time RT-PCR and immunoblotting. Using primary wild-type and TXNIP-deficient islets, we then assessed the effects of palmitate on apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]), mitochondrial death pathway (cytochrome c release), and endoplasmic reticulum (ER) stress (binding protein [BiP], C/EBP homologous protein [CHOP]). Effects of TXNIP deficiency were also tested in the context of staurosporine (mitochondrial damage) or thapsigargin (ER stress). Glucose elicited a dramatic increase in islet TXNIP expression both in vitro and in vivo, whereas fatty acids had no such effect and, when combined with glucose, even abolished the glucose effect. We also found that TXNIP deficiency does not effectively protect against palmitate or thapsigargin-induced beta-cell apoptosis, but specifically prevents staurosporine- or glucose-induced toxicity. Our results demonstrate that unlike glucose, fatty acids do not induce beta-cell expression of proapoptotic TXNIP. They further reveal that TXNIP deficiency specifically inhibits the mitochondrial death pathway underlying beta-cell glucotoxicity, whereas it has very few protective effects against ER stress-mediated lipoapoptosis.

  7. NMR signal transducer

    International Nuclear Information System (INIS)

    Kucheryaev, A.G.; Oliferchuk, N.L.

    1975-01-01

    A signal transducer of nuclear magnetic resonance for simultaneously measuring frequency and intensitivity of two various isotope signals, which are in one specimen is described. The transducer represents radiofrequency circuit with two resonance frequences, which is common for two autodyne generators. To decrease measuring time and to increase recording diagram stability the radiofrequency circuit has LC netork, in the inductivity of which investigated specimen is located; a circuit variable capacity is connected in parallel with one of the autodyne generators. Besides the radiofrequency circuit has an inductance coil in series with a standard specimen inside as well as a variable capacitor connected in parallel with the second autodyne generator. An amplitude of oscillation of each resonance frequency is controlled and adjusted separately. The transducer described can be used for the measurement of a nuclei concentration, isotope concentration and for the spin determination

  8. Ethyl Acetate Extract of Scindapsus cf. hederaceus Exerts the Inhibitory Bioactivity on Human Non-Small Cell Lung Cancer Cells through Modulating ER Stress

    Directory of Open Access Journals (Sweden)

    Chon-Kit Chou

    2018-06-01

    Full Text Available Unfolded protein response (UPR is a cytoprotective mechanism that alleviates the protein-folding burden in eukaryotic organisms. Moderate activation of UPR is required for maintaining endoplasmic reticulum (ER homeostasis and profoundly contributes to tumorigenesis. Defects in UPR signaling are implicated in the attenuation of various malignant phenotypes including cell proliferation, migration, and invasion, as well as angiogenesis. This suggests UPR as a promising target in cancer therapy. The pharmacological effects of the plant Scindapsus cf. hederaceus on human cancer cell lines is not understood. In this study, we identified an ethyl acetate extract from Scindapsus cf. hederaceus (SH-EAE, which markedly altered the protein expression of UPR-related genes in human non-small cell lung cancer (NSCLC cells. Treatment with the SH-EAE led to the dose-dependent suppression of colony forming ability of both H1299 and H460 cells, but not markedly in normal bronchial epithelial BEAS-2B cells. SH-EAE treatment also attenuated the migration and invasion ability of H1299 and H460 cells. Moreover, SH-EAE strikingly suppressed the protein expression of two ER stress sensors, including inositol requiring enzyme-1α (IRE-1α and protein kinase R-like ER kinase (PERK, and antagonized the induction of C/EBP homologous protein (CHOP expression by thapsigargin, an ER stress inducer. SH-EAE induced the formation of massive vacuoles which are probably derived from ER. Importantly, SH-EAE impaired the formation of intersegmental vessels (ISV in zebrafish larvae, an index of angiogenesis, but had no apparent effect on the rate of larval development. Together, our findings demonstrate, for the first time, that the ability of SH-EAE specifically targets the two sensors of UPR, with significant anti-proliferation and anti-migration activities as a crude extract in human NSCLC cells. Our finding also indicates potential applications of SH-EAE in preventing UPR

  9. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Castro, David; Kosel, Jü rgen; Foulds, Ian G.

    2016-01-01

    contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT

  10. Vibration transducer calibration techniques

    Science.gov (United States)

    Brinkley, D. J.

    1980-09-01

    Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

  11. Salubrinal protects human skin fibroblasts against UVB-induced cell death by blocking endoplasmic reticulum (ER) stress and regulating calcium homeostasis.

    Science.gov (United States)

    Ji, Chao; Yang, Bo; Huang, Shu-Ying; Huang, Jin-Wen; Cheng, Bo

    2017-12-02

    The role of UVB in skin photo damages has been widely reported. Overexposure to UVB will induce severe DNA damages in epidermal cells and cause most cytotoxic symptoms. In the present study, we tested the potential activity of salubrinal, a selective inhibitor of Eukaryotic Initiation Factor 2 (eIF2) -alpha phosphatase, against UV-induced skin cell damages. We first exposed human fibroblasts to UVB radiation and evaluated the cytosolic Ca 2+ level as well as the induction of ER stress. We found that UVB radiation induced the depletion of ER Ca 2+ and increased the expression of ER stress marker including phosphorylated PERK, CHOP, and phosphorylated IRE1α. We then determined the effects of salubrinal in skin cell death induced by UVB radiation. We observed that cells pre-treated with salubrinal had a higher survival rate compared to cells treated with UVB alone. Pre-treatment with salubrinal successfully re-established the ER function and Ca 2+ homeostasis. Our results suggest that salubrinal can be a potential therapeutic agents used in preventing photoaging and photo damages. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Involvement of ER Stress in Dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 Missense Mutations Shown by iPSC-Derived Oligodendrocytes

    Directory of Open Access Journals (Sweden)

    Yuko Numasawa-Kuroiwa

    2014-05-01

    Full Text Available Pelizaeus-Merzbacher disease (PMD is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1 gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.

  13. ER Stress and Autophagic Perturbations Lead to Elevated Extracellular α-Synuclein in GBA-N370S Parkinson's iPSC-Derived Dopamine Neurons

    Directory of Open Access Journals (Sweden)

    Hugo J.R. Fernandes

    2016-03-01

    Full Text Available Heterozygous mutations in the glucocerebrosidase gene (GBA represent the strongest common genetic risk factor for Parkinson's disease (PD, the second most common neurodegenerative disorder. However, the molecular mechanisms underlying this association are still poorly understood. Here, we have analyzed ten independent induced pluripotent stem cell (iPSC lines from three controls and three unrelated PD patients heterozygous for the GBA-N370S mutation, and identified relevant disease mechanisms. After differentiation into dopaminergic neurons, we observed misprocessing of mutant glucocerebrosidase protein in the ER, associated with activation of ER stress and abnormal cellular lipid profiles. Furthermore, we observed autophagic perturbations and an enlargement of the lysosomal compartment specifically in dopamine neurons. Finally, we found increased extracellular α-synuclein in patient-derived neuronal culture medium, which was not associated with exosomes. Overall, ER stress, autophagic/lysosomal perturbations, and elevated extracellular α-synuclein likely represent critical early cellular phenotypes of PD, which might offer multiple therapeutic targets.

  14. Proteomic analysis of INS-1 rat insulinoma cells: ER stress effects and the protective role of exenatide, a GLP-1 receptor agonist.

    Directory of Open Access Journals (Sweden)

    Mi-Kyung Kim

    Full Text Available Beta cell death caused by endoplasmic reticulum (ER stress is a key factor aggravating type 2 diabetes. Exenatide, a glucagon-like peptide (GLP-1 receptor agonist, prevents beta cell death induced by thapsigargin, a selective inhibitor of ER calcium storage. Here, we report on our proteomic studies designed to elucidate the underlying mechanisms. We conducted comparative proteomic analyses of cellular protein profiles during thapsigargin-induced cell death in the absence and presence of exenatide in INS-1 rat insulinoma cells. Thapsigargin altered cellular proteins involved in metabolic processes and protein folding, whose alterations were variably modified by exenatide treatment. We categorized the proteins with thapsigargin initiated alterations into three groups: those whose alterations were 1 reversed by exenatide, 2 exaggerated by exenatide, and 3 unchanged by exenatide. The most significant effect of thapsigargin on INS-1 cells relevant to their apoptosis was the appearance of newly modified spots of heat shock proteins, thimet oligopeptidase and 14-3-3β, ε, and θ, and the prevention of their appearance by exenatide, suggesting that these proteins play major roles. We also found that various modifications in 14-3-3 isoforms, which precede their appearance and promote INS-1 cell death. This study provides insights into the mechanisms in ER stress-caused INS-1 cell death and its prevention by exenatide.

  15. ALS Patient Stem Cells for Unveiling Disease Signatures of Motoneuron Susceptibility: Perspectives on the Deadly Mitochondria, ER Stress and Calcium Triad

    Science.gov (United States)

    Kaus, Anjoscha; Sareen, Dhruv

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a largely sporadic progressive neurodegenerative disease affecting upper and lower motoneurons (MNs) whose specific etiology is incompletely understood. Mutations in superoxide dismutase-1 (SOD1), TAR DNA-binding protein 43 (TARDBP/TDP-43) and C9orf72, have been identified in subsets of familial and sporadic patients. Key associated molecular and neuropathological features include ubiquitinated TDP-43 inclusions, stress granules, aggregated dipeptide proteins from mutant C9orf72 transcripts, altered mitochondrial ultrastructure, dysregulated calcium homeostasis, oxidative and endoplasmic reticulum (ER) stress, and an unfolded protein response (UPR). Such impairments have been documented in ALS animal models; however, whether these mechanisms are initiating factors or later consequential events leading to MN vulnerability in ALS patients is debatable. Human induced pluripotent stem cells (iPSCs) are a valuable tool that could resolve this “chicken or egg” causality dilemma. Relevant systems for probing pathophysiologically affected cells from large numbers of ALS patients and discovering phenotypic disease signatures of early MN susceptibility are described. Performing unbiased ‘OMICS and high-throughput screening in relevant neural cells from a cohort of ALS patient iPSCs, and rescuing mitochondrial and ER stress impairments, can identify targeted therapeutics for increasing MN longevity in ALS. PMID:26635528

  16. Interactome Screening Identifies the ER Luminal Chaperone Hsp47 as a Regulator of the Unfolded Protein Response Transducer IRE1α.

    Science.gov (United States)

    Sepulveda, Denisse; Rojas-Rivera, Diego; Rodríguez, Diego A; Groenendyk, Jody; Köhler, Andres; Lebeaupin, Cynthia; Ito, Shinya; Urra, Hery; Carreras-Sureda, Amado; Hazari, Younis; Vasseur-Cognet, Mireille; Ali, Maruf M U; Chevet, Eric; Campos, Gisela; Godoy, Patricio; Vaisar, Tomas; Bailly-Maitre, Béatrice; Nagata, Kazuhiro; Michalak, Marek; Sierralta, Jimena; Hetz, Claudio

    2018-01-18

    Maintenance of endoplasmic reticulum (ER) proteostasis is controlled by a dynamic signaling network known as the unfolded protein response (UPR). IRE1α is a major UPR transducer, determining cell fate under ER stress. We used an interactome screening to unveil several regulators of the UPR, highlighting the ER chaperone Hsp47 as the major hit. Cellular and biochemical analysis indicated that Hsp47 instigates IRE1α signaling through a physical interaction. Hsp47 directly binds to the ER luminal domain of IRE1α with high affinity, displacing the negative regulator BiP from the complex to facilitate IRE1α oligomerization. The regulation of IRE1α signaling by Hsp47 is evolutionarily conserved as validated using fly and mouse models of ER stress. Hsp47 deficiency sensitized cells and animals to experimental ER stress, revealing the significance of Hsp47 to global proteostasis maintenance. We conclude that Hsp47 adjusts IRE1α signaling by fine-tuning the threshold to engage an adaptive UPR. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Nano-optomechanical transducer

    Science.gov (United States)

    Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul

    2013-12-03

    A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

  18. Stress wave focusing transducers

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  19. Steerable Doppler transducer probes

    International Nuclear Information System (INIS)

    Fidel, H.F.; Greenwood, D.L.

    1986-01-01

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis

  20. Induction of apoptosis through ER stress and TP53 in MCF-7 cells by the nanoparticle [Gd@C82(OH)22]n: A systems biology study.

    Science.gov (United States)

    Wang, Lin; Meng, Jie; Cao, Weipeng; Li, Qizhai; Qiu, Yuqing; Sun, Baoyun; Li, Lei M

    2014-06-01

    The nanoparticle gadolinium endohedral metallofullerenol [Gd@C82(OH)22]n is a new candidate for cancer treatment with low toxicity. However, its anti-cancer mechanisms remain mostly unknown. In this study, we took a systems biology view of the gene expression profiles of human breast cancer cells (MCF-7) and human umbilical vein endothelial cells (ECV304) treated with and without [Gd@C82(OH)22]n, respectively, measured by the Agilent Gene Chip G4112F. To properly analyze these data, we modified a suit of statistical methods we developed. For the first time we applied the sub-sub normalization to Agilent two-color microarrays. Instead of a simple linear regression, we proposed to use a one-knot SPLINE model in the sub-sub normalization to account for nonlinear spatial effects. The parameters estimated by least trimmed squares- and S-estimators show similar normalization results. We made several kinds of inferences by integrating the expression profiles with the bioinformatic knowledge in KEGG pathways, Gene Ontology, JASPAR, and TRANSFAC. In the transcriptional inference, we proposed the BASE2.0 method to infer a transcription factor's up-regulation and down-regulation activities separately. Overall, [Gd@C82(OH)22]n induces more differentiation in MCF-7 cells than in ECV304 cells, particularly in the reduction of protein processing such as protein glucosylation, folding, targeting, exporting, and transporting. Among the KEGG pathways, the ErbB signaling pathway is up-regulated, whereas protein processing in endoplasmic reticulum (ER) is down-regulated. CHOP, a key pro-apoptotic gene downstream of the ER stress pathway, increases to nine folds in MCF-7 cells after treatment. These findings indicate that ER stress may be one important factor that induces apoptosis in MCF-7 cells after [Gd@C82(OH)22]n treatment. The expression profiles of genes associated with ER stress and apoptosis are statistically consistent with other profiles reported in the literature, such as

  1. Molybdenum induces pancreatic β-cell dysfunction and apoptosis via interdependent of JNK and AMPK activation-regulated mitochondria-dependent and ER stress-triggered pathways

    International Nuclear Information System (INIS)

    Yang, Tsung-Yuan; Yen, Cheng-Chieh; Lee, Kuan-I; Su, Chin-Chuan; Yang, Ching-Yao; Wu, Chin-Ching; Hsieh, Shang-Shu; Ueng, Kwo-Chang; Huang, Chun-Fa

    2016-01-01

    Molybdenum (Mo), a well-known toxic environmental and industrial pollutant, causes adverse health effects and diseases in humans and has received attention as a potential risk factor for DM. However, the roles of Mo in the mechanisms of the toxicological effects in pancreatic β-cells are mostly unclear. In this study, the results revealed dysfunction of insulin secretion and apoptosis in the pancreatic β-cell-derived RIN-m5F cells and the isolated mouse islets in response to Mo. These effects were accompanied by a mitochondria-dependent apoptotic signals including a decreased in the MMP, an increase in cytochrome c release, and the activation of caspase cascades and PARP. In addition, ER stress was triggered as indicated by several key molecules of the UPR. Furthermore, exposure to Mo induced the activation of ERK1/2, JNK, AMPKα, and GSK3-α/β. Pretreatment with specific pharmacological inhibitors (in RIN-m5F cells and isolated mouse islets) of JNK (SP600125) and AMPK (Compound C) or transfection with si-RNAs (in RIN-m5F cells) specific to JNK and AMPKα effectively prevented the Mo-induced apoptosis and related signals, but inhibitors of ERK1/2 and GSK3-α/β (PD98059 and LiCl, respectively) did not reverse the Mo-induced effects. Additionally, both the inhibitors and specific si-RNAs could suppress the Mo-induced phosphorylation of JNK and AMPKα each other. Taken together, these results suggest that Mo exerts its cytotoxicity on pancreatic β-cells by inducing dysfunction and apoptosis via interdependent JNK and AMPK activation downstream-regulated mitochondrial-dependent and ER stress-triggered apoptosis pathways. - Highlights: • Molybdenum (Mo) induces pancreatic β-cell dysfunction and apoptosis. • Mo causes β-cell death via mitochondria-dependent caspase cascades signals. • ER stress-triggered apoptotic pathway also regulates Mo-induced β-cell death. • Interdependent of JNK and AMPK activation involves in Mo-induced β-cell apoptosis.

  2. Molybdenum induces pancreatic β-cell dysfunction and apoptosis via interdependent of JNK and AMPK activation-regulated mitochondria-dependent and ER stress-triggered pathways

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tsung-Yuan [Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Yen, Cheng-Chieh [Department of Occupational Safety and Health, College of Health Care and Management, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Lee, Kuan-I [Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan (China); Su, Chin-Chuan [Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County 500, Taiwan (China); Graduate Institute of Basic Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung 404, Taiwan (China); Yang, Ching-Yao [Department of Surgery, National Taiwan University Hospital, Taipei 100, Taiwan (China); Department of Surgery, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Wu, Chin-Ching [Department of Public Health, China Medical University, Taichung 404, Taiwan (China); Hsieh, Shang-Shu, E-mail: gile1123@yahoo.com.tw [Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan (China); Ueng, Kwo-Chang, E-mail: kcueng@gmail.com [Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Huang, Chun-Fa, E-mail: cfhuang@mail.cmu.edu.tw [School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung 404, Taiwan (China)

    2016-03-01

    Molybdenum (Mo), a well-known toxic environmental and industrial pollutant, causes adverse health effects and diseases in humans and has received attention as a potential risk factor for DM. However, the roles of Mo in the mechanisms of the toxicological effects in pancreatic β-cells are mostly unclear. In this study, the results revealed dysfunction of insulin secretion and apoptosis in the pancreatic β-cell-derived RIN-m5F cells and the isolated mouse islets in response to Mo. These effects were accompanied by a mitochondria-dependent apoptotic signals including a decreased in the MMP, an increase in cytochrome c release, and the activation of caspase cascades and PARP. In addition, ER stress was triggered as indicated by several key molecules of the UPR. Furthermore, exposure to Mo induced the activation of ERK1/2, JNK, AMPKα, and GSK3-α/β. Pretreatment with specific pharmacological inhibitors (in RIN-m5F cells and isolated mouse islets) of JNK (SP600125) and AMPK (Compound C) or transfection with si-RNAs (in RIN-m5F cells) specific to JNK and AMPKα effectively prevented the Mo-induced apoptosis and related signals, but inhibitors of ERK1/2 and GSK3-α/β (PD98059 and LiCl, respectively) did not reverse the Mo-induced effects. Additionally, both the inhibitors and specific si-RNAs could suppress the Mo-induced phosphorylation of JNK and AMPKα each other. Taken together, these results suggest that Mo exerts its cytotoxicity on pancreatic β-cells by inducing dysfunction and apoptosis via interdependent JNK and AMPK activation downstream-regulated mitochondrial-dependent and ER stress-triggered apoptosis pathways. - Highlights: • Molybdenum (Mo) induces pancreatic β-cell dysfunction and apoptosis. • Mo causes β-cell death via mitochondria-dependent caspase cascades signals. • ER stress-triggered apoptotic pathway also regulates Mo-induced β-cell death. • Interdependent of JNK and AMPK activation involves in Mo-induced β-cell apoptosis.

  3. ER stress and basement membrane defects combine to cause glomerular and tubular renal disease resulting from Col4a1 mutations in mice

    Directory of Open Access Journals (Sweden)

    Frances E. Jones

    2016-02-01

    Full Text Available Collagen IV is a major component of basement membranes, and mutations in COL4A1, which encodes collagen IV alpha chain 1, cause a multisystemic disease encompassing cerebrovascular, eye and kidney defects. However, COL4A1 renal disease remains poorly characterized and its pathomolecular mechanisms are unknown. We show that Col4a1 mutations in mice cause hypotension and renal disease, including proteinuria and defects in Bowman's capsule and the glomerular basement membrane, indicating a role for Col4a1 in glomerular filtration. Impaired sodium reabsorption in the loop of Henle and distal nephron despite elevated aldosterone levels indicates that tubular defects contribute to the hypotension, highlighting a novel role for the basement membrane in vascular homeostasis by modulation of the tubular response to aldosterone. Col4a1 mutations also cause diabetes insipidus, whereby the tubular defects lead to polyuria associated with medullary atrophy and a subsequent reduction in the ability to upregulate aquaporin 2 and concentrate urine. Moreover, haematuria, haemorrhage and vascular basement membrane defects confirm an important vascular component. Interestingly, although structural and compositional basement membrane defects occurred in the glomerulus and Bowman's capsule, no tubular basement membrane defects were detected. By contrast, medullary atrophy was associated with chronic ER stress, providing evidence for cell-type-dependent molecular mechanisms of Col4a1 mutations. These data show that both basement membrane defects and ER stress contribute to Col4a1 renal disease, which has important implications for the development of treatment strategies for collagenopathies.

  4. Oxidative and ER stress-dependent ASK1 activation in steatotic hepatocytes and Kupffer cells sensitizes mice fatty liver to ischemia/reperfusion injury.

    Science.gov (United States)

    Imarisio, Chiara; Alchera, Elisa; Bangalore Revanna, Chandrashekar; Valente, Guido; Follenzi, Antonia; Trisolini, Elena; Boldorini, Renzo; Carini, Rita

    2017-11-01

    Steatosis intensifies hepatic ischemia/reperfusion (I/R) injury increasing hepatocyte damage and hepatic inflammation. This study evaluates if this process is associated to a differential response of steatotic hepatocytes (HP) and Kupffer cells (KC) to I/R injury and investigates the molecular mechanisms involved. Control or steatotic (treated with 50 μmol palmitic acid, PA) mouse HP or KC were exposed to hypoxia/reoxygenation (H/R). C57BL/6 mice fed 9 week with control or High Fat diet underwent to partial hepatic IR. PA increased H/R damage of HP and further activated the ASK1-JNK axis stimulated by ER stress during H/R. PA also induced the production of oxidant species (OS), and OS prevention nullified the capacity of PA to increase H/R damage and ASK1/JNK stimulation. ASK1 inhibition prevented JNK activation and entirely protected HP damage. In KC, PA directly activated ER stress, ASK1 and p38 MAPK and increased H/R damage. However, in contrast to HP, ASK1 inhibition further increased H/R damage by preventing p38 MAPK activation. In mice liver, steatosis induced the expression of activated ASK1 in only KC, whereas I/R exposure of steatotic liver activated ASK1 expression also in HP. "In vivo", ASK1 inhibition prevented ASK1, JNK and p38 MAPK activation and protected I/R damage and expression of inflammatory markers. Lipids-induced ASK1 stimulation differentially affects HP and KC by promoting cytotoxic or protective signals. ASK1 increases H/R damage of HP by stimulating JNK and protects KC activating p38MAPK. These data support the potentiality of the therapeutic employment of ASK1 inhibitors that can antagonize the damaging effects of I/R upon fatty liver surgery by the contextual reduction of HP death and of KC-mediated reactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. The effect of metformin treatment on endoplasmic reticulum (ER stress induced by status epilepticus (SE via the PERK-eIF2α-CHOP pathway

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2018-02-01

    Full Text Available Status epilepticus (SE is defined as continuous seizure activity lasting more than 5 minutes. It results in neuronal cell death, mediated by endoplasmic reticulum (ER stress response. Previously, metformin demonstrated neuroprotective effects in primary cortical neurons. In this study, we analyzed the effect of metformin on ER stress via the pro-apoptotic protein kinase RNA-like endoplasmic reticulum kinase (PERK-eukaryotic initiation factor 2α (eIF2α-C/EBP homologous protein (CHOP pathway. SE was induced in rats by pentylenetetrazole. Following SE, the rats were treated with salubrinal, GSK2656157, or metformin. In a control group (normal saline SE was not induced. CHOP, eIF2α, and PERK expression was determined by Western blot; apoptosis was analyzed by TUNEL assay. CHOP expression was significantly increased at 6 and 24 hours following SE. At both time points, eIF2α and PERK levels were also increased. At 6 hours, CHOP expression was significantly reduced in salubrinal, GSK2656157 and metformin groups versus SE group. eIF2α and PERK levels were decreased in metformin compared to SE group. eIF2α expression was markedly decreased in salubrinal versus SE group, while PERK expression was markedly reduced in GSK2656157 versus SE group. At 6 and 24 hours, the apoptosis rate was significantly increased in SE versus control group, while it was significantly reduced in salubrinal, GSK2656157, and metformin groups compared to SE group. The apoptosis rate also decreased in salubrinal group at 24 hours, although not to the extent observed in metformin group. Overall, CHOP expression and apoptosis induced by SE in rats were reduced with metformin. Further studies are required to evaluate the clinical relevance of metformin for patients with SE.

  6. Numerical Transducer Modeling

    DEFF Research Database (Denmark)

    Henriquez, Vicente Cutanda

    This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... manipulations are developed to satisfy the more complicated boundary conditions, and a model of a condenser microphone with a coupled membrane is developed. The model is tested against measurements of ¼ inch condenser microphones and analytical calculations. A detailed discussion of the results is given....

  7. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  8. The Chemical Chaperone, PBA, Reduces ER Stress and Autophagy and Increases Collagen IV α5 Expression in Cultured Fibroblasts From Men With X-Linked Alport Syndrome and Missense Mutations

    Directory of Open Access Journals (Sweden)

    Dongmao Wang

    2017-07-01

    Discussion: Sodium 4-phenylbutyrate increases collagen IV α5 mRNA levels, reduces ER stress and autophagy, and possibly facilitates collagen IV α5 extracellular transport. Whether these actions delay end-stage renal failure in men with X-linked Alport syndrome and missense mutations will only be determined with clinical trials.

  9. The dynamics of histone H2A ubiquitination in HeLa cells exposed to rapamycin, ethanol, hydroxyurea, ER stress, heat shock and DNA damage.

    Science.gov (United States)

    Nakata, Shiori; Watanabe, Tadashi; Nakagawa, Koji; Takeda, Hiroshi; Ito, Akihiro; Fujimuro, Masahiro

    2016-03-25

    Polyubiquitination plays key roles in proteasome-dependent and independent cellular events, whereas monoubiquitination is involved in gene expression, DNA repair, protein-protein interaction, and protein trafficking. We previously developed an FK2 antibody, which specifically recognizes poly-Ub moieties but not free Ub. To elucidate the role of Ub conjugation in response to cellular stress, we used FK2 to investigate whether chemical stress (rapamycin, ethanol, or hydroxyurea), ER stress (thapsigargin or tunicamycin), heat shock or DNA damage (H2O2 or methyl methanesulfonate) affect the formation of Ub conjugates including histone H2A (hH2A) ubiquitination. First, we found that all forms of stress tested increased poly-ubiquitinated proteins in HeLa cells. Furthermore, rapamycin and hydroxyurea treatment, and ER stress increased ubiquitination of hH2A, while methyl methanesulfonate (MMS) treatment induced deubiquitination of hH2A. The ethanol and H2O2 treatments, and heat shock transiently induced hH2A de-ubiquitination, although deubiquitinated hH2A were ubiquitinated again by subsequent cultivation. We also revealed that FK2 reacts with not only polyubiquitinated proteins but also mono-ubiquitinated hH2A. With the exception of MMS, all forms of stress tested increased the acetylation of K5-hH2A, K9-hH3 and K8-hH4 in addition to ubiquitination. K118 and K119 of hH2A were ubiquitinated in cells under normal conditions, and K119 was the major ubiquitination site. The MMS-treatment and heat shock induced the deubiquitination of both K118 and K119-histone H2A. Interestingly, MMS treatment did not affect cell HeLa cell viability expressing double-mutant hH2A (KK118,119AA-hH2A), while heat shock slightly but significantly decreased viability of double-mutant hH2A expressing cells, indicating that ubiquitination of both sites associates with recovery from heat shock but not MMS treatment. Thus, we characterized FK2 reactivity and demonstrated that various stresses alter

  10. Circuit for Driving Piezoelectric Transducers

    Science.gov (United States)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

    The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

  11. Micromachined Integrated Transducers for Ultrasound Imaging

    DEFF Research Database (Denmark)

    la Cour, Mette Funding

    The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...

  12. Auranofin induces apoptosis by ROS-mediated ER stress and mitochondrial dysfunction and displayed synergistic lethality with piperlongumine in gastric cancer.

    Science.gov (United States)

    Zou, Peng; Chen, Minxiao; Ji, Jiansong; Chen, Weiqian; Chen, Xi; Ying, Shilong; Zhang, Junru; Zhang, Ziheng; Liu, Zhiguo; Yang, Shulin; Liang, Guang

    2015-11-03

    Gastric cancer (GC) is one of the leading causes of cancer mortality in the world. In addressing the need of treatments for relapsed disease, we report the identification of an existing U.S. Food and Drug Administration-approved small-molecule drug to repurpose for GC treatment. Auranofin (AF), clinically used to treat rheumatic arthritis, but it exhibited preclinical efficacy in GC cells. By increasing intracellular reactive oxygen species (ROS) levels, AF induces a lethal endoplasmic reticulum stress response and mitochondrial dysfunction in cultured GC cells. Blockage of ROS production reversed AF-induced ER stress and mitochondrial pathways activation as well as apoptosis. In addition, AF displays synergistic lethality with an ROS-generating agent piperlongumine, which is a natural product isolated from the long pepper Piper longum L. Taken together, this work provides a novel anticancer candidate for the treatment of gastric cancer. More importantly, it reveals that increased ROS generation might be an effective strategy in treating human gastric cancer.

  13. Organometallic Gold(III) Complexes Similar to Tetrahydroisoquinoline Induce ER-Stress-Mediated Apoptosis and Pro-Death Autophagy in A549 Cancer Cells.

    Science.gov (United States)

    Huang, Ke-Bin; Wang, Feng-Yang; Tang, Xiao-Ming; Feng, Hai-Wen; Chen, Zhen-Feng; Liu, Yan-Cheng; Liu, You-Nian; Liang, Hong

    2018-04-26

    Agents inducing both apoptosis and autophagic death can be effective chemotherapeutic drugs. In our present work, we synthesized two organometallic gold(III) complexes harboring C^N ligands that structurally resemble tetrahydroisoquinoline (THIQ): Cyc-Au-1 (AuL 1 Cl 2 , L 1 = 3,4-dimethoxyphenethylamine) and Cyc-Au-2 (AuL 2 Cl 2 , L 2 = methylenedioxyphenethylamine). In screening their in vitro activity, we found both gold complexes exhibited lower toxicity, lower resistance factors, and better anticancer activity than those of cisplatin. The organometallic gold(III) complexes accumulate in mitochondria and induce elevated ROS and an ER stress response through mitochondrial dysfunction. These effects ultimately result in simultaneous apoptosis and autophagy. Importantly, compared to cisplatin, Cyc-Au-2 exhibits lower toxicity and better anticancer activity in a murine tumor model. To the best of our knowledge, Cyc-Au-2 is the first organometallic Au(III) compound that induces apoptosis and autophagic death. On the basis of our results, we believe Cyc-Au-2 to be a promising anticancer agent or lead compound for further anticancer drug development.

  14. Chronic Insulin Exposure Induces ER Stress and Lipid Body Accumulation in Mast Cells at the Expense of Their Secretory Degranulation Response.

    Directory of Open Access Journals (Sweden)

    William E Greineisen

    Full Text Available Lipid bodies (LB are reservoirs of precursors to inflammatory lipid mediators in immunocytes, including mast cells. LB numbers are dynamic, increasing dramatically under conditions of immunological challenge. We have previously shown in vitro that insulin-influenced lipogenic pathways induce LB biogenesis in mast cells, with their numbers attaining steatosis-like levels. Here, we demonstrate that in vivo hyperinsulinemia resulting from high fat diet is associated with LB accumulation in murine mast cells and basophils. We characterize the lipidome of purified insulin-induced LB, and the shifts in the whole cell lipid landscape in LB that are associated with their accumulation, in both model (RBL2H3 and primary mast cells. Lipidomic analysis suggests a gain of function associated with LB accumulation, in terms of elevated levels of eicosanoid precursors that translate to enhanced antigen-induced LTC4 release. Loss-of-function in terms of a suppressed degranulation response was also associated with LB accumulation, as were ER reprogramming and ER stress, analogous to observations in the obese hepatocyte and adipocyte. Taken together, these data suggest that chronic insulin elevation drives mast cell LB enrichment in vitro and in vivo, with associated effects on the cellular lipidome, ER status and pro-inflammatory responses.

  15. Inhibition of CLIC4 enhances autophagy and triggers mitochondrial and ER stress-induced apoptosis in human glioma U251 cells under starvation.

    Directory of Open Access Journals (Sweden)

    Jiateng Zhong

    Full Text Available CLIC4/mtCLIC, a chloride intracellular channel protein, localizes to mitochondria, endoplasmic reticulum (ER, nucleus and cytoplasm, and participates in the apoptotic response to stress. Apoptosis and autophagy, the main types of the programmed cell death, seem interconnected under certain stress conditions. However, the role of CLIC4 in autophagy regulation has yet to be determined. In this study, we demonstrate upregulation and nuclear translocation of the CLIC4 protein following starvation in U251 cells. CLIC4 siRNA transfection enhanced autophagy with increased LC3-II protein and puncta accumulation in U251 cells under starvation conditions. In that condition, the interaction of the 14-3-3 epsilon isoform with CLIC4 was abolished and resulted in Beclin 1 overactivation, which further activated autophagy. Moreover, inhibiting the expression of CLIC4 triggered both mitochondrial apoptosis involved in Bax/Bcl-2 and cytochrome c release under starvation and endoplasmic reticulum stress-induced apoptosis with CHOP and caspase-4 upregulation. These results demonstrate that CLIC4 nuclear translocation is an integral part of the cellular response to starvation. Inhibiting the expression of CLIC4 enhances autophagy and contributes to mitochondrial and ER stress-induced apoptosis under starvation.

  16. Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

    Science.gov (United States)

    Cai, Yanxue; Zhang, Xianwen; Zhou, Xiaoshuang; Wu, Xiaoli; Li, Yanhui; Yao, Jianhua; Bai, Jie

    2017-03-01

    Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP + ) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP + , which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP + . The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP + /MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. An enzyme logic bioprotonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Takeo; Keene, Scott; Deng, Yingxin; Rolandi, Marco, E-mail: rolandi@uw.edu [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-2120 (United States); Josberger, Erik E. [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-2120 (United States); Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States)

    2015-01-01

    Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdH{sub x} electrode as a bioprotonic transducer that connects H{sup +} currents in solution into an electronic signal. This transducer exploits the reversible formation of PdH{sub x} in solution according to PdH↔Pd + H{sup +} + e{sup −}, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic AND gate for glucose and NAD{sup +}. PdH{sub x} formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.

  18. Deubiquitinase inhibitor b-AP15 activates endoplasmic reticulum (ER) stress and inhibits Wnt/Notch1 signaling pathway leading to the reduction of cell survival in hepatocellular carcinoma cells.

    Science.gov (United States)

    Ding, Youming; Chen, Xiaoyan; Wang, Bin; Yu, Bin; Ge, Jianhui

    2018-04-15

    b-AP15, a potent and selective inhibitor of the ubiquitin-specific peptidase 14 (USP14), displays in vitro and in vivo antitumor abilities on some types of cancer cells. However, the mechanism underlying its action is not well elucidated. The purposes of the present study are to observe the potential impacts of b-AP15 on cell survival of hepatocellular carcinoma cells and to investigate whether and how this compound inhibits some survival-promoting signaling pathways. We found that b-AP15 significantly decreased cell viability and increased cell apoptosis in a dose-dependent manner in hepatocellular carcinoma cells, along with the perturbation of cell cycle and the decreased expressions of cell cycle-related proteins. We also demonstrated that the endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) were enhanced by b-AP15 supplementation. The inhibition of ER stress/UPR only partly attenuated the cytotoxicity of b-AP15 on hepatocellular carcinoma cells. In addition, b-AP15 treatment inhibited Wnt/β-catenin and Notch1 signaling pathways, and suppressed phosphorylation of STAT3, Akt, and Erk1/2, which were not restored by the inhibition of ER stress/UPR. Furthermore, the expression levels of signaling molecules in Notch1 were reduced by specific inhibitor of Wnt/β-catenin pathway. Notably, either Wnt or Notch1 signaling inhibitor mitigated phosphorylation of STAT3, Akt, and Erk1/2, and mimicked the cytotoxicity of b-AP15 on hepatocellular carcinoma cells. These results clearly indicate that b-AP15 induced cytotoxic response to hepatocellular carcinoma cells by augmenting ER stress/UPR and inhibiting Wnt/Notch1 signaling pathways. This new finding provides a novel mechanism by which b-AP15 produces its antitumor therapeutic effects. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Trans10,cis12 conjugated linoleic acid inhibits proliferation and migration of ovarian cancer cells by inducing ER stress, autophagy, and modulation of Src.

    Directory of Open Access Journals (Sweden)

    Mian M K Shahzad

    Full Text Available The goal of this study was to investigate the anti-cancer effects of Trans10,cis12 conjugated linoleic acid (t10,c12 CLA. MTT assays and QCM™ chemotaxis 96-wells were used to test the effect of t10,c12 CLA on the proliferation and migration and invasion of cancer cells. qPCR and Western Blotting were used to determine the expression of specific factors. RNA sequencing was conducted using the Illumina platform and apoptosis was measured using a flow cytometry assay. t10,c12 CLA (IC50, 7 μM inhibited proliferation of ovarian cancer cell lines SKOV-3 and A2780. c9,t11 CLA did not attenuate the proliferation of these cells. Transcription of 165 genes was significantly repressed and 28 genes were elevated. Genes related to ER stress, ATF4, CHOP, and GADD34 were overexpressed whereas EDEM2 and Hsp90, genes required for proteasomal degradation of misfolded proteins, were downregulated upon treatment. While apoptosis was not detected, t10,c12 CLA treatment led to 9-fold increase in autophagolysosomes and higher levels of LC3-II. G1 cell cycle arrest in treated cells was correlated with phosphorylation of GSK3β and loss of β-catenin. microRNA miR184 and miR215 were upregulated. miR184 likely contributed to G1 arrest by downregulating E2F1. miR215 upregulation was correlated with increased expression of p27/Kip-1. t10,c12 CLA-mediated inhibition of invasion and migration correlated with decreased expression of PTP1b and decreased Src activation by inhibiting phosphorylation at Tyr416. Due to its ability to inhibit proliferation and migration, t10,c12 CLA should be considered for treatment of ovarian cancer.

  20. Vapb/Amyotrophic lateral sclerosis 8 knock-in mice display slowly progressive motor behavior defects accompanying ER stress and autophagic response.

    Science.gov (United States)

    Larroquette, Frédérique; Seto, Lesley; Gaub, Perrine L; Kamal, Brishna; Wallis, Deeann; Larivière, Roxanne; Vallée, Joanne; Robitaille, Richard; Tsuda, Hiroshi

    2015-11-15

    Missense mutations (P56S) in Vapb are associated with autosomal dominant motor neuron diseases: amyotrophic lateral sclerosis and lower motor neuron disease. Although transgenic mice overexpressing the mutant vesicle-associated membrane protein-associated protein B (VAPB) protein with neuron-specific promoters have provided some insight into the toxic properties of the mutant proteins, their role in pathogenesis remains unclear. To identify pathological defects in animals expressing the P56S mutant VAPB protein at physiological levels in the appropriate tissues, we have generated Vapb knock-in mice replacing wild-type Vapb gene with P56S mutant Vapb gene and analyzed the resulting pathological phenotypes. Heterozygous P56S Vapb knock-in mice show mild age-dependent defects in motor behaviors as characteristic features of the disease. The homozygous P56S Vapb knock-in mice show more severe defects compared with heterozygous mice reflecting the dominant and dose-dependent effects of P56S mutation. Significantly, the knock-in mice demonstrate accumulation of P56S VAPB protein and ubiquitinated proteins in cytoplasmic inclusions, selectively in motor neurons. The mutant mice demonstrate induction of ER stress and autophagic response in motor neurons before obvious onset of behavioral defects, suggesting that these cellular biological defects might contribute to the initiation of the disease. The P56S Vapb knock-in mice could be a valuable tool to gain a better understanding of the mechanisms by which the disease arises. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Hericium erinaceus mycelium and its isolated erinacine A protection from MPTP-induced neurotoxicity through the ER stress, triggering an apoptosis cascade.

    Science.gov (United States)

    Kuo, Hsing-Chun; Lu, Chien-Chang; Shen, Chien-Heng; Tung, Shui-Yi; Hsieh, Meng Chiao; Lee, Ko-Chao; Lee, Li-Ya; Chen, Chin-Chu; Teng, Chih-Chuan; Huang, Wen-Shih; Chen, Te-Chuan; Lee, Kam-Fai

    2016-03-18

    Hericium erinaceus is an edible mushroom; its various pharmacological effects which have been investigated. This study aimed to demonstrate whether efficacy of oral administration of H. erinaceus mycelium (HEM) and its isolated diterpenoid derivative, erinacine A, can act as an anti-neuroinflammatory agent to bring about neuroprotection using an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model of Parkinson's disease, which results in motor disturbances, in addition to elucidating the mechanisms involved. Mice were treated with and without HEM or erinacine A, after MPTP injection for brain injuries by the degeneration of dopaminergic nigrostriatal neurons. The efficacy of oral administration of HEM improved MPTP-induced loss of tyrosine hydroxylase positive neurons and brain impairment in the substantia nigra pars compacta as measured by brain histological examination. Treatment with HEM reduced MPTP-induced dopaminergic cell loss, apoptotic cell death induced by oxidative stress, as well as the level of glutathione, nitrotyrosine and 4-hydroxy-2-nonenal (4-HNE). Furthermore, HEM reversed MPTP-associated motor deficits, as revealed by the analysis of rotarod assessment. Our results demonstrated that erinacine A decreases the impairment of MPP-induced neuronal cell cytotoxicity and apoptosis, which were accompanied by ER stress-sustained activation of the IRE1α/TRAF2, JNK1/2 and p38 MAPK pathways, the expression of C/EBP homologous protein (CHOP), IKB-β and NF-κB, as well as Fas and Bax. These physiological and brain histological changes provide HEM neuron-protective insights into the progression of Parkinson's disease, and this protective effect seems to exist both in vivo and in vitro.

  2. Trans10,cis12 conjugated linoleic acid inhibits proliferation and migration of ovarian cancer cells by inducing ER stress, autophagy, and modulation of Src.

    Science.gov (United States)

    Shahzad, Mian M K; Felder, Mildred; Ludwig, Kai; Van Galder, Hannah R; Anderson, Matthew L; Kim, Jong; Cook, Mark E; Kapur, Arvinder K; Patankar, Manish S

    2018-01-01

    The goal of this study was to investigate the anti-cancer effects of Trans10,cis12 conjugated linoleic acid (t10,c12 CLA). MTT assays and QCM™ chemotaxis 96-wells were used to test the effect of t10,c12 CLA on the proliferation and migration and invasion of cancer cells. qPCR and Western Blotting were used to determine the expression of specific factors. RNA sequencing was conducted using the Illumina platform and apoptosis was measured using a flow cytometry assay. t10,c12 CLA (IC50, 7 μM) inhibited proliferation of ovarian cancer cell lines SKOV-3 and A2780. c9,t11 CLA did not attenuate the proliferation of these cells. Transcription of 165 genes was significantly repressed and 28 genes were elevated. Genes related to ER stress, ATF4, CHOP, and GADD34 were overexpressed whereas EDEM2 and Hsp90, genes required for proteasomal degradation of misfolded proteins, were downregulated upon treatment. While apoptosis was not detected, t10,c12 CLA treatment led to 9-fold increase in autophagolysosomes and higher levels of LC3-II. G1 cell cycle arrest in treated cells was correlated with phosphorylation of GSK3β and loss of β-catenin. microRNA miR184 and miR215 were upregulated. miR184 likely contributed to G1 arrest by downregulating E2F1. miR215 upregulation was correlated with increased expression of p27/Kip-1. t10,c12 CLA-mediated inhibition of invasion and migration correlated with decreased expression of PTP1b and decreased Src activation by inhibiting phosphorylation at Tyr416. Due to its ability to inhibit proliferation and migration, t10,c12 CLA should be considered for treatment of ovarian cancer.

  3. Characterization of Dielectric Electroactive Polymer transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Møller, Martin B.; Sarban, Rahimullah

    2014-01-01

    This paper analysis the small-signal model of the Dielectric Electro Active Polymer (DEAP) transducer. The DEAP transducer have been proposed as an alternative to the electrodynamic transducer in sound reproduction systems. In order to understand how the DEAP transducer works, and provide...

  4. Gemcitabine treatment induces endoplasmic reticular (ER) stress and subsequently upregulates urokinase plasminogen activator (uPA) to block mitochondrial-dependent apoptosis in Panc-1 cancer stem-like cells (CSCs).

    Science.gov (United States)

    Wang, Li; Zhang, Yi; Wang, Weiguo; Zhu, Yunjie; Chen, Yang; Tian, Bole

    2017-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with poor survival rates. The presence of cancer stem-like cells (CSCs) is believed to be among the underlying reasons for the aggressiveness of PDAC, which contributes to chemoresistance and recurrence. However, the mechanisms that induce chemoresistance and inhibit apoptosis remain largely unknown. We used serum-free medium to enrich CSCs from panc-1 human pancreatic cancer cells and performed sphere formation testing, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and semi-quantitative western blotting to confirm the stemness of panc-1 CSCs. Hallmarks of endoplasmic reticulum (ER) stress, including IRE1, PERK, ATF4, ATF6α, GRP78 and uPA expression, were detected after gemcitabine treatment. Effects of gemcitabine-induced uPA expression on cell invasion, sphere formation, colony formation and gemcitabine sensitivity were detected. Electrophoretic mobility shift assays (EMSAs) and RNA-immunoprecipitation (RIP) were performed to detect interaction between the uPA mRNA 3'-UTR and mutant p53-R273H expressed by panc-1 CSCs. The effects of upregulated uPA by gemcitabine on apoptosis were detected by Annexin V-FITC/PI staining, and the impact of uPA on small molecule CP-31398-restored mutant p53 transcriptional activity was measured by a luciferase reporter assay. Enriched panc-1 CSCs expressing high levels of CD44 and CD133 also produced significantly higher amounts of Oct4 and Nanog. Compared with panc-1 cells, panc-1 CSCs presented chemoresistance to gemcitabine. ER stress gene detections demonstrated effects of gemcitabine-induced ER stress on both the pro-apoptotic and pro-survival branches. ER stress-induced ATF6α upregulated level of uPA by transcriptionally activating GRP78. Gemcitabine-induced uPA promoted invasion, sphere formation and colony formation and attenuated apoptosis induced by gemcitabine in panc-1 CSCs, depending on interaction with mutant p53

  5. Familial CJD Associated PrP Mutants within Transmembrane Region Induced Ctm-PrP Retention in ER and Triggered Apoptosis by ER Stress in SH-SY5Y Cells

    Science.gov (United States)

    Wang, Xin; Shi, Qi; Xu, Kun; Gao, Chen; Chen, Cao; Li, Xiao-Li; Wang, Gui-Rong; Tian, Chan; Han, Jun; Dong, Xiao-Ping

    2011-01-01

    Background Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP) gene that are presumed to favor conversion of the cellular isoform of PrP (PrPC) to the pathogenic one (PrPSc). The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K) into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. Methodology/Principal Findings To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER), the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL) and PrP with three amino acids exchange in transmembrane region (PrP-3AV) were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP) were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and capase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V) induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K) failed. Conclusions/Significance The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them the mutants

  6. Familial CJD associated PrP mutants within transmembrane region induced Ctm-PrP retention in ER and triggered apoptosis by ER stress in SH-SY5Y cells.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available BACKGROUND: Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP gene that are presumed to favor conversion of the cellular isoform of PrP (PrP(C to the pathogenic one (PrP(Sc. The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. METHODOLOGY/PRINCIPAL FINDINGS: To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER, the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL and PrP with three amino acids exchange in transmembrane region (PrP-3AV were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and caspase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K failed. CONCLUSIONS/SIGNIFICANCE: The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them

  7. Auto-positioning ultrasonic transducer system

    Science.gov (United States)

    Buchanan, Randy K. (Inventor)

    2010-01-01

    An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

  8. Model of a Piezoelectric Transducer

    Science.gov (United States)

    Goodenow, Debra

    2004-01-01

    It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to

  9. MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress.

    Directory of Open Access Journals (Sweden)

    Qi Wang

    Full Text Available BACKGROUND: To investigate if microRNAs (miRNAs play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders. METHODS: We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+ current. RESULTS: H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2, with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking. CONCLUSIONS: Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.

  10. MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress.

    Science.gov (United States)

    Wang, Qi; Hu, Weina; Lei, Mingming; Wang, Yong; Yan, Bing; Liu, Jun; Zhang, Ren; Jin, Yuanzhe

    2013-01-01

    To investigate if microRNAs (miRNAs) play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders. We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+) current. H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2), with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking. Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.

  11. DEVELOPMENTAL STUDIES OF NUCLEAR DIGITAL TRANSDUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, James L.

    1963-09-15

    A pressure transducer based on mechanical modulation of a beam of alpha particles is described. This type of transducer is capable of direct digital pressure measurexnent with corresponding telemetry advantages. Any variable that is sensed through a mechanical displacement is measurable by means of a corresponding member of this transducer family. Preliminary tests of an experimental pressure transducer show an overall accuracy within a few tenths of one percent, with promise of substantial improvement. General characteristics of nuclear digital transducers include exceptional long-term calibration stability and accuracy, independent of ambient environmental effects. Three concepts of systems enipioying these transducers are discussed. (auth)

  12. Acoustic Levitation With One Transducer

    Science.gov (United States)

    Barmatz, Martin B.

    1987-01-01

    Higher resonator modes enables simplification of equipment. Experimental acoustic levitator for high-temperature containerless processing has round cylindrical levitation chamber and only one acoustic transducer. Stable levitation of solid particle or liquid drop achieved by exciting sound in chamber to higher-order resonant mode that makes potential well for levitated particle or drop at some point within chamber.

  13. Proceedings of transducer 84 conference

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    In the broad and varied field of sensors this conference reviews thermal sensors for temperature measurements, gas sensors for gas analysis (for example analysis of exhaust gases from vehicles), optical fiber sensors, applications for optics, mechanics, robotics and signal processing. In particular one of the applications concerns acoustical transducers operating in liquid sodium for LMFBR reactors.

  14. Calculations for Piezoelectric Ultrasonic Transducers

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1986-01-01

    Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a boay which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation...

  15. Irradiation Testing of Ultrasonic Transducers

    International Nuclear Information System (INIS)

    Daw, J.; Rempe, J.; Palmer, J.; Tittmann, B.; Reinhardt, B.; Kohse, G.; Ramuhalli, P.; Montgomery, R.; Chien, H.T.; Villard, J.F.

    2013-06-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of numerous parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10 21 n/cm 2 (E> 0.1 MeV). This test will be an instrumented lead test; and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. By characterizing magnetostrictive and piezoelectric transducer survivability during irradiation, test results will enable the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. (authors)

  16. The research on high power transducer

    International Nuclear Information System (INIS)

    Zhao Wuling; Li Yubin; Peng Shuwen

    2014-01-01

    This paper introduces the transducer structure used double PWM mode, the control system design of hardware and software. The transducer has been applied in factory. From the real experiment, it shows that the system has a high reliability. (authors)

  17. A Direct Driver for Electrostatic Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes a power stage suitable for driving an electrostatic transducer under biasing. Measurement results of a ±400 V prototype amplifier are shown. THD below 1% is reported....

  18. Digital electrostatic acoustic transducer array

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

  19. Digital electrostatic acoustic transducer array

    KAUST Repository

    Carreno, Armando Arpys Arevalo; Castro, David; Conchouso Gonzalez, David; Kosel, Jü rgen; Foulds, Ian G.

    2016-01-01

    In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

  20. Calculations for piezoelectric ultrasonic transducers

    International Nuclear Information System (INIS)

    Jensen, H.

    1986-05-01

    Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a body which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation losses as well as internal losses may be important. Due to the complexity of the problem, a closed form solution is the exception rather than the rule. For this reason, it is necessary to use approximate methods for the analysis. Equivalent circuits, the Rayleigh-Ritz method, Mindlin plate theory and in particular the finite element method are considered. The finite element method is utilized for analysis of axisymmetric transducers. An explicit, fully piezoelectric, triangular ring element, with linear variations in displacement and electric potential is given. The influence of a fluid half-space is also given, in the form of a complex stiffness matrix. A special stacking procedure, for analysis of the backing has been developed. This procedure gives a saving, which is similar to that of the fast fourier transform algorithm, and is also wellsuited for analysis of finite and infinite waveguides. Results obtained by the finite element method are shown and compared with measurements and exact solutions. Good agreement is obtained. It is concluded that the finite element method can be a valueable tool in analysis and design of ultrasonic transducers. (author)

  1. Transducers

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B

    stream_size 27 stream_content_type text/plain stream_name Encycl_Microcomputers_18_335.pdf.txt stream_source_info Encycl_Microcomputers_18_335.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  2. Acetic Acid Causes Endoplasmic Reticulum Stress and Induces the Unfolded Protein Response in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Nozomi Kawazoe

    2017-06-01

    Full Text Available Since acetic acid inhibits the growth and fermentation ability of Saccharomyces cerevisiae, it is one of the practical hindrances to the efficient production of bioethanol from a lignocellulosic biomass. Although extensive information is available on yeast response to acetic acid stress, the involvement of endoplasmic reticulum (ER and unfolded protein response (UPR has not been addressed. We herein demonstrated that acetic acid causes ER stress and induces the UPR. The accumulation of misfolded proteins in the ER and activation of Ire1p and Hac1p, an ER-stress sensor and ER stress-responsive transcription factor, respectively, were induced by a treatment with acetic acid stress (>0.2% v/v. Other monocarboxylic acids such as propionic acid and sorbic acid, but not lactic acid, also induced the UPR. Additionally, ire1Δ and hac1Δ cells were more sensitive to acetic acid than wild-type cells, indicating that activation of the Ire1p-Hac1p pathway is required for maximum tolerance to acetic acid. Furthermore, the combination of mild acetic acid stress (0.1% acetic acid and mild ethanol stress (5% ethanol induced the UPR, whereas neither mild ethanol stress nor mild acetic acid stress individually activated Ire1p, suggesting that ER stress is easily induced in yeast cells during the fermentation process of lignocellulosic hydrolysates. It was possible to avoid the induction of ER stress caused by acetic acid and the combined stress by adjusting extracellular pH.

  3. Radiation-resistant pressure transducers

    International Nuclear Information System (INIS)

    Abbasov, Sh.M.; Kerimova, T.I.

    2005-01-01

    Full text : The sensitive element of vibrofrequency tensor converter (VTC) is an electromechanical resonator of string type with electrostatic excitation of longitudinal mechanical vibrations. The string is made from tensosensitive thread-like monocrystal n-Ge1-x Six (length 1-5 mm, diameter 8-12 mcm) with current outlet and strictly fixed by ends at plate or deformable surface (in elastic element) at 50 mcm apartheid. With increasing Si atomic percent in n-Ge1-x Six the converter tens sensitivity increases. There has been shown the scheme of pressure transducer which contains monocrystalline silicon membrane and string tens converter from thread-like monocrystal Ge-Si. Using method, when crystal position on membrane while it deforms by pressure, corresponds to free (uptight) state, allowed to obtain the maximum sensitivity in measurement of pressure fluctuation. The transducers of absolute and pressure differential of this type can be used in automated systems of life activity. The high sensitivity of string transducers to pressure exceeding 100 hertz/mm (water column) permits to use them in devices for measuring gas concentration. The combination of optical and deformation methods of measurements forms the basis of their operation. The pressure change occurs due to the fact that gas molecules absorbing the quanta of incident light, become at excited state and then excitation energy of their vibrational-rotatory degrees of freedom converts to the energy of translational motion of molecules, i.e. to heat appropriate to pressure increase. Using these tens converters of high pressure one can prevent the possible accidents on oil pipe-like Baku-Tibilisi-Ceyhan

  4. Micromachined capacitive ultrasonic immersion transducer array

    Science.gov (United States)

    Jin, Xuecheng

    Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

  5. LAVA Pressure Transducer Trade Study

    Science.gov (United States)

    Oltman, Samuel B.

    2016-01-01

    The Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload will transport the (LAVA) subsystem to hydrogen-rich locations on the moon supporting NASA's in-situ resource utilization (ISRU) programs. There, the LAVA subsystem will analyze volatiles that evolve from heated regolith samples in order to quantify how much water is present. To do this, the system needs resilient pressure transducers (PTs) to calculate the moles in the gas samples. The PT trade study includes a comparison of newly-procured models to a baseline unit with prior flight history in order to determine the PT model with the best survivability in flight-forward conditions.

  6. Micromachined Ultrasonic Transducers for 3-D Imaging

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann

    of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce...... such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... treatment of CMUTs is presented, including investigations of the anisotropic plate behaviour and modal radiation patterns of such devices. Several new CMUT fabrication approaches are developed and investigated in terms of oxide quality and surface protrusions, culminating in a simple four-mask process...

  7. The Dynamic Performance of Flexural Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Andrew Feeney

    2018-01-01

    Full Text Available Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems.

  8. Transducers and arrays for underwater sound

    CERN Document Server

    Butler, John L

    2016-01-01

    This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

  9. Standards for dielectric elastomer transducers

    International Nuclear Information System (INIS)

    Carpi, Federico; Frediani, Gabriele; Anderson, Iain; Bauer, Siegfried; Gallone, Giuseppe; Gei, Massimiliano; Graaf, Christian; Jean-Mistral, Claire; Kaal, William; Kofod, Guggi; Kollosche, Matthias; Kornbluh, Roy; Pelrine, Ron; Lassen, Benny; Rechenbach, Björn; Matysek, Marc; Michel, Silvain; Nowak, Stephan; O’Brien, Benjamin; Pei, Qibing

    2015-01-01

    Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this field calls for the first standards, collecting guidelines on how to assess and compare the performance of materials and devices. This paper addresses this need, presenting standardized methods for material characterisation, device testing and performance measurement. These proposed standards are intended to have a general scope and a broad applicability to different material types and device configurations. Nevertheless, they also intentionally exclude some aspects where knowledge and/or consensus in the literature were deemed to be insufficient. This is a sign of a young and vital field, whose research development is expected to benefit from this effort towards standardisation. (paper)

  10. Standards for dielectric elastomer transducers

    Science.gov (United States)

    Carpi, Federico; Anderson, Iain; Bauer, Siegfried; Frediani, Gabriele; Gallone, Giuseppe; Gei, Massimiliano; Graaf, Christian; Jean-Mistral, Claire; Kaal, William; Kofod, Guggi; Kollosche, Matthias; Kornbluh, Roy; Lassen, Benny; Matysek, Marc; Michel, Silvain; Nowak, Stephan; O'Brien, Benjamin; Pei, Qibing; Pelrine, Ron; Rechenbach, Björn; Rosset, Samuel; Shea, Herbert

    2015-10-01

    Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this field calls for the first standards, collecting guidelines on how to assess and compare the performance of materials and devices. This paper addresses this need, presenting standardized methods for material characterisation, device testing and performance measurement. These proposed standards are intended to have a general scope and a broad applicability to different material types and device configurations. Nevertheless, they also intentionally exclude some aspects where knowledge and/or consensus in the literature were deemed to be insufficient. This is a sign of a young and vital field, whose research development is expected to benefit from this effort towards standardisation.

  11. High-fructose diet is as detrimental as high-fat diet in the induction of insulin resistance and diabetes mediated by hepatic/pancreatic endoplasmic reticulum (ER) stress.

    Science.gov (United States)

    Balakumar, M; Raji, L; Prabhu, D; Sathishkumar, C; Prabu, P; Mohan, V; Balasubramanyam, M

    2016-12-01

    In the context of high human consumption of fructose diets, there is an imperative need to understand how dietary fructose intake influence cellular and molecular mechanisms and thereby affect β-cell dysfunction and insulin resistance. While evidence exists for a relationship between high-fat-induced insulin resistance and metabolic disorders, there is lack of studies in relation to high-fructose diet. Therefore, we attempted to study the effect of different diets viz., high-fat diet (HFD), high-fructose diet (HFS), and a combination (HFS + HFD) diet on glucose homeostasis and insulin sensitivity in male Wistar rats compared to control animals fed with normal pellet diet. Investigations include oral glucose tolerance test, insulin tolerance test, histopathology by H&E and Masson's trichrome staining, mRNA expression by real-time PCR, protein expression by Western blot, and caspase-3 activity by colorimetry. Rats subjected to high-fat/fructose diets became glucose intolerant, insulin-resistant, and dyslipidemic. Compared to control animals, rats subjected to different combination of fat/fructose diets showed increased mRNA and protein expression of a battery of ER stress markers both in pancreas and liver. Transcription factors of β-cell function (INSIG1, SREBP1c and PDX1) as well as hepatic gluconeogenesis (FOXO1 and PEPCK) were adversely affected in diet-induced insulin-resistant rats. The convergence of chronic ER stress towards apoptosis in pancreas/liver was also indicated by increased levels of CHOP mRNA & increased activity of both JNK and Caspase-3 in rats subjected to high-fat/fructose diets. Our study exposes the experimental support in that high-fructose diet is equally detrimental in causing metabolic disorders.

  12. A new high performance current transducer

    International Nuclear Information System (INIS)

    Tang Lijun; Lu Songlin; Li Deming

    2003-01-01

    A DC-100 kHz current transducer is developed using a new technique on zero-flux detecting principle. It was shown that the new current transducer is of high performance, its magnetic core need not be selected very stringently, and it is easy to manufacture

  13. Using Portable Transducers to Measure Tremor Severity

    Directory of Open Access Journals (Sweden)

    Rodger Elble

    2016-05-01

    Full Text Available Background: Portable motion transducers, suitable for measuring tremor, are now available at a reasonable cost. The use of these transducers requires knowledge of their limitations and data analysis. The purpose of this review is to provide a practical overview and example software for using portable motion transducers in the quantification of tremor. Methods: Medline was searched via PubMed.gov in December 2015 using the Boolean expression “tremor AND (accelerometer OR accelerometry OR gyroscope OR inertial measurement unit OR digitizing tablet OR transducer.” Abstracts of 419 papers dating back to 1964 were reviewed for relevant portable transducers and methods of tremor analysis, and 105 papers written in English were reviewed in detail. Results: Accelerometers, gyroscopes, and digitizing tablets are used most commonly, but few are sold for the purpose of measuring tremor. Consequently, most software for tremor analysis is developed by the user. Wearable transducers are capable of recording tremor continuously, in the absence of a clinician. Tremor amplitude, frequency, and occurrence (percentage of time with tremor can be computed. Tremor amplitude and occurrence correlate strongly with clinical ratings of tremor severity. Discussion: Transducers provide measurements of tremor amplitude that are objective, precise, and valid, but the precision and accuracy of transducers are mitigated by natural variability in tremor amplitude. This variability is so great that the minimum detectable change in amplitude, exceeding random variability, is comparable for scales and transducers. Research is needed to determine the feasibility of detecting smaller change using averaged data from continuous long-term recordings with wearable transducers.

  14. Capacitance high temperature strain transducer by Interatom

    International Nuclear Information System (INIS)

    Fortmann, M.

    1987-01-01

    Special strain transducers are necessary to perform structure mechanical experiments on real components under creep-fatigue load. The new development of the transducer was able to solve the problem. In the meantime, different characteristics of the transducer have been examined and many successful applications have been effected. Some important aspects are given in this report. Up to now the longest operation period has been 24000 h on a pipe at 630 0 C service temperature in a conventional power station. (orig./DG) [de

  15. Serum levels of RBP4 and adipose tissue levels of PTP1B are increased in obese men resident in northeast Scotland without associated changes in ER stress response genes

    Directory of Open Access Journals (Sweden)

    Hoggard N

    2012-05-01

    Full Text Available Nigel Hoggard1, Abdelali Agouni2, Nimesh Mody2, Mirela Delibegovic21Rowett Institute of Nutrition and Health, 2Integrative Physiology, University of Aberdeen, Aberdeen, UKBackground: Retinol-binding protein 4 (RBP4 is an adipokine identified as a marker of insulin resistance in mice and humans. Protein tyrosine phosphatase 1B (PTP1B expression levels as well as other genes involved in the endoplasmic reticulum (ER stress response are increased in adipose tissue of obese, high-fat-diet-fed mice. In this study we investigated if serum and/or adipose tissue RBP4 protein levels and expression levels of PTP1B and other ER stress-response genes are altered in obese and obese/diabetic men resident in northeast Scotland.Methods: We studied three groups of male volunteers: (1 normal/overweight (body mass index [BMI] < 30, (2 obese (BMI > 30, and (3 obese/diabetic (BMI > 30 controlling their diabetes either by diet or the antidiabetic drug metformin. We analyzed their serum and adipose tissue RBP4 protein levels as well as adipose tissue mRNA expression of PTP1B, binding immunoglobulin protein (BIP, activated transcription factor 4 (ATF4, and glucose-regulated protein 94 (GRP94 alongside other markers of adiposity (percentage body fat, leptin, cholesterol, triglycerides and insulin resistance (oral glucose tolerance tests, insulin, homeostatic model assessment–insulin resistance, C-reactive protein, and adiponectin.Results: We found that obese Scottish subjects had significantly higher serum RBP4 protein levels in comparison to the normal/overweight subjects (P < 0.01. Serum RBP4 levels were normalized in obese/diabetic subjects treated with diet or metformin (P < 0.05. Adipose tissue RBP4 protein levels were comparable between all three groups of subjects as were serum and adipose transthyretin levels. Adipose tissue PTP1B mRNA levels were increased in obese subjects in comparison to normal/overweight subjects (P < 0.05; however diet and/or metformin

  16. Transducers and microprocessors in oceanographic applications

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Desa, E.

    Transducers used for the sensing of the ten most measured marine parameters have been described in this paper. The ten parameters have been classed under 5 sensor types, namely temperature, pressure, salinity, currents and waves. For each sensor...

  17. Performance of Honeywell silicon pressure transducers

    Digital Repository Service at National Institute of Oceanography (India)

    VijayKumar, K.; Joseph, A.; Desai, R.G.P.; Nagvekar, S.; Prabhudesai, S.; Damodaran, V.

    pressure. The precision pressure transducer – ruggedized (PPTR) manufactured by Honeywell is provided with a special “Hastelloy” material isolation-diaphragm to protect the transducer port against corrosive effects during its prolonged exposure...-scale output (an intelligent technique anufacturers to hide the non-linearity of the product at all data points below ore realistic estimate of linearity is obtained by ean of a few samples) based on the corresponding true ethod employed by performance...

  18. Down-regulation of 14-3-3β exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP–Wnt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lei; Lei, Hui; Chang, Ming-Ze; Liu, Zhi-Qin [Department of Neurological Disease, Xi' an Central Hospital, Xi' an Jiaotong University, Xi' an, Shaanxi 710000 (China); Bie, Xiao-Hua, E-mail: biexiaohua_xjtu@126.com [Department of Functional Neurosurgery, Xi' an Red Cross Hospital, Xi' an Jiaotong University, Xi' an, Shaanxi 710054 (China)

    2015-07-10

    We previously identified 14-3-3β as a tumor-specific isoform of 14-3-3 protein in astrocytoma, but its functional role in glioma cells and underlying mechanisms are poorly understood. In the present study, we investigated the effects of 14-3-3β inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA). The results showed that 14-3-3β is highly expressed in U87 cells but not in normal astrocyte SVGp12 cells. Knockdown of 14-3-3β by Si-14-3-3β transfection significantly decreased the cell viability but increased the LDH release in a time-dependent fashion in U87 cells, and these effects were accompanied with G0/G1 cell cycle arrest and apoptosis. In addition, 14-3-3β knockdown induced ER stress in U87 cells, as evidenced by ER calcium release, increased expression of XBP1S mRNA and induction of ER related pro-apoptotic factors. Down-regulation of 14-3-3β significantly decreased the nuclear localization of β-catenin and inhibited Topflash activity, which was shown to be reversely correlated with CHOP. Furthermore, Si-CHOP and sFRP were used to inhibit CHOP and Wnt, respectively. The results showed that the anti-cancer effects of 14-3-3β knockdown in U87 cells were mediated by increased expression of CHOP and followed inhibition of Wnt/β-catenin pathway. In summary, the remarkable efficiency of 14-3-3β knockdown to induce apoptotic cell death in U87 cells may find therapeutic application for the treatment of glioma patients. - Highlights: • Knockdown of 14-3-3β leads to cytotoxicity in human glioma U87 cells. • Knockdown of 14-3-3β induces cell cycle arrest and apoptosis in U87 cells. • Knockdown of 14-3-3β results in ER stress in U87 cells. • Knockdown of 14-3-3β inhibits Wnt/β-catenin pathway via CHOP activation.

  19. Down-regulation of 14-3-3β exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP–Wnt pathway

    International Nuclear Information System (INIS)

    Cao, Lei; Lei, Hui; Chang, Ming-Ze; Liu, Zhi-Qin; Bie, Xiao-Hua

    2015-01-01

    We previously identified 14-3-3β as a tumor-specific isoform of 14-3-3 protein in astrocytoma, but its functional role in glioma cells and underlying mechanisms are poorly understood. In the present study, we investigated the effects of 14-3-3β inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA). The results showed that 14-3-3β is highly expressed in U87 cells but not in normal astrocyte SVGp12 cells. Knockdown of 14-3-3β by Si-14-3-3β transfection significantly decreased the cell viability but increased the LDH release in a time-dependent fashion in U87 cells, and these effects were accompanied with G0/G1 cell cycle arrest and apoptosis. In addition, 14-3-3β knockdown induced ER stress in U87 cells, as evidenced by ER calcium release, increased expression of XBP1S mRNA and induction of ER related pro-apoptotic factors. Down-regulation of 14-3-3β significantly decreased the nuclear localization of β-catenin and inhibited Topflash activity, which was shown to be reversely correlated with CHOP. Furthermore, Si-CHOP and sFRP were used to inhibit CHOP and Wnt, respectively. The results showed that the anti-cancer effects of 14-3-3β knockdown in U87 cells were mediated by increased expression of CHOP and followed inhibition of Wnt/β-catenin pathway. In summary, the remarkable efficiency of 14-3-3β knockdown to induce apoptotic cell death in U87 cells may find therapeutic application for the treatment of glioma patients. - Highlights: • Knockdown of 14-3-3β leads to cytotoxicity in human glioma U87 cells. • Knockdown of 14-3-3β induces cell cycle arrest and apoptosis in U87 cells. • Knockdown of 14-3-3β results in ER stress in U87 cells. • Knockdown of 14-3-3β inhibits Wnt/β-catenin pathway via CHOP activation

  20. High Temperature, High Power Piezoelectric Composite Transducers

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  1. Mechano-electric optoisolator transducer with hysteresis

    International Nuclear Information System (INIS)

    Ciurus, I M; Dimian, M; Graur, A

    2011-01-01

    This article presents a theoretical and experimental study of designing a mechano-electric optoisolator transducer with hysteresis. Our research is centred upon designing transducers on the basis of optical sensors, as photoelectric conversions eliminate the influence of electromagnetic disturbances. Conversion of the rotation/translation motions into electric signals is performed with the help of a LED-photoresistor Polaroid optocoupler. The driver of the optocoupler's transmitter module is an independent current source. The signal conditioning circuit is a Schmitt trigger circuit. The device is designed to be applied in the field of automation and mechatronics.

  2. Immune Algorithm Complex Method for Transducer Calibration

    Directory of Open Access Journals (Sweden)

    YU Jiangming

    2014-08-01

    Full Text Available As a key link in engineering test tasks, the transducer calibration has significant influence on accuracy and reliability of test results. Because of unknown and complex nonlinear characteristics, conventional method can’t achieve satisfactory accuracy. An Immune algorithm complex modeling approach is proposed, and the simulated studies on the calibration of third multiple output transducers is made respectively by use of the developed complex modeling. The simulated and experimental results show that the Immune algorithm complex modeling approach can improve significantly calibration precision comparison with traditional calibration methods.

  3. Translational control of human acetyl-CoA carboxylase 1 mRNA is mediated by an internal ribosome entry site in response to ER stress, serum deprivation or hypoxia mimetic CoCl2.

    Science.gov (United States)

    Damiano, Fabrizio; Testini, Mariangela; Tocci, Romina; Gnoni, Gabriele V; Siculella, Luisa

    2018-04-01

    Acetyl-CoA carboxylase 1 (ACC1) is a cytosolic enzyme catalyzing the rate limiting step in de novo fatty acid biosynthesis. There is mounting evidence showing that ACC1 is susceptible to dysregulation and that it is over-expressed in liver diseases associated with lipid accumulation and in several cancers. In the present study, ACC1 regulation at the translational level is reported. Using several experimental approaches, the presence of an internal ribosome entry site (IRES) has been established in the 5' untranslated region (5' UTR) of the ACC1 mRNA. Transfection experiments with the ACC1 5' UTR inserted in a dicistronic reporter vector show a remarkable increase in the downstream cistron translation, through a cap-independent mechanism. The endoplasmic reticulum (ER) stress condition and the related unfolded protein response (UPR), triggered by treatment with thapsigargin and tunicamycin, cause an increase of the cap-independent translation of ACC1 mRNA in HepG2 cells, despite the overall reduction in global protein synthesis. Other stress conditions, such as serum starvation and incubation with hypoxia mimetic agent CoCl 2 , up-regulate ACC1 expression in HepG2 cells at the translational level. Overall, these findings indicate that the presence of an IRES in the ACC1 5' UTR allows ACC1 mRNA translation in conditions that are inhibitory to cap-dependent translation. A potential involvement of the cap-independent translation of ACC1 in several pathologies, such as obesity and cancer, has been discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Bifunctional role of ephrin A1-Eph system in stimulating cell proliferation and protecting cells from cell death through the attenuation of ER stress and inflammatory responses in bovine mammary epithelial cells.

    Science.gov (United States)

    Kang, Minkyung; Jeong, Wooyoung; Bae, Hyocheol; Lim, Whasun; Bazer, Fuller W; Song, Gwonhwa

    2018-03-01

    Structural and functional development of the mammary gland is constant in the mammary gland life cycle. Eph receptors and their ligands, ephrins, control events through cell-to-cell interactions during embryonic development, and adult tissue homeostasis; however, little information on participation of ephrin A1, a representative ligand of the Eph receptor, in the development and function of normal mammary glands is known. In this study, we demonstrated functional effects of the ephrin A1-Eph system and mechanisms of its action on bovine mammary epithelial (MAC-T) cells. The in vitro cultured MAC-T cells expressed the ephrin A1 ligand and EphA1, A2, A4, A7, and A8 among the eight members of the Eph A family. Our results revealed that ephrin A1 induced MAC-T cell cycle progression and stimulated cell proliferation with abundant expression of nucleic PCNA and cyclin D1 proteins. Additionally, ephrin A1 induced activation of intracellular signaling molecules involved in PI3 K/AKT and MAPK signaling, and the proliferation-stimulating effect of ephrin A1 was mediated by activation of these pathways. Furthermore, ephrin A1 influenced expression and activation of various ER stress-related proteins and protected MAC-T cells from stress-induced cell death. Finally, ephrin A1 alleviated LPS-induced cell death through down-regulation of inflammatory cytokines. In conclusion, the results of this study suggest that the Eph A-ephrin A1 system is a positive factor in the increase and maintenance of epithelial cells in mammary glands of cows; the signaling system contributes to development, remodeling, and functionality of normal mammary glands and could overcome mastitis in cows and other mammals. © 2017 Wiley Periodicals, Inc.

  5. Fiber-optic coupled pressure transducer

    International Nuclear Information System (INIS)

    Tallman, C.R.; Wingate, F.P.; Ballard, E.O.

    1979-01-01

    A fiber-optic coupled pressure transducer was developed for measurement of pressure transients produced by fast electrical discharges in laser cavities. A detailed description of the design and performance will be given. Shock tube performance and measurements in direct electrical discharge regions will be presented

  6. Eliminating transducer distortion in acoustic measurements

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Torras Rosell, Antoni; McWalter, Richard Ian

    2014-01-01

    This paper investigates the in uence of nonlinear components that contaminate the linear response of acoustic transducer, and presents a method for eliminating the in uence of nonlinearities in acoustic measurements. The method is evaluated on simulated as well as experimental data, and is shown...

  7. Ferroelectret non-contact ultrasonic transducers

    Czech Academy of Sciences Publication Activity Database

    Bovtun, Viktor; Döring, J.; Bartusch, J.; Beck, U.; Erhard, A.; Yakymenko, Y.

    2007-01-01

    Roč. 88, č. 4 (2007), s. 737-743 ISSN 0947-8396 R&D Projects: GA ČR(CZ) GA202/06/0403 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectrets * polymers * ultrasonic transducers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.857, year: 2007

  8. Linearization of resistance thermometers and other transducers

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1970-01-01

    deflection output or to null balance output. The application to the common temperature transducers is considered. It is shown that thermistors, linear metals (e.g., copper), and nickel can be linearized in terms of temperature, but platinum cannot be. If linearization is desired in terms of the reciprocal...

  9. Characterisation and Modelling of MEMS Ultrasonic Transducers

    International Nuclear Information System (INIS)

    Teng, M F; Hariz, A J

    2006-01-01

    Silicon ultrasonic transducer micro arrays based on micro-electro-mechanicalsystem (MEMS) technologies are gaining popularity for applications in sonar sensing and excitation. A current challenge for many researchers is modelling the dynamic performance of these and other micro-mechanical devices to ascertain their performance and explain experimental observations reported. In this work, the performance simulation of a MEMS ultrasonic transducer array made from silicon nitride has been successfully carried out using CoventorWare package. The dynamic response of the entire transducer array was characterised, and the results were compared with theoretical predictions. Individual elements were found to vibrate with Bessel-like displacement patterns, and they were resonant at approximately 3 MHz, depending on thickness and lateral dimensions. The frequency shows a linear dependence around the common thickness of 2 μm. Peak displacement levels were examined as a function of frequency, DC bias voltage, and AC drive voltage. Accounting for fabrication variations, and uniformity variations across the wafer, the full array showed minimal variations in peak out-of-plane displacement levels across the device, and isolated elements that were over-responsive and under-responsive. Presently, the effect of observed variations across the array on the performance of the transducers and their radiated fields are being examined

  10. Features calibration of the dynamic force transducers

    Science.gov (United States)

    Sc., M. Yu Prilepko D.; Lysenko, V. G.

    2018-04-01

    The article discusses calibration methods of dynamic forces measuring instruments. The relevance of work is dictated by need to valid definition of the dynamic forces transducers metrological characteristics taking into account their intended application. The aim of this work is choice justification of calibration method, which provides the definition dynamic forces transducers metrological characteristics under simulation operating conditions for determining suitability for using in accordance with its purpose. The following tasks are solved: the mathematical model and the main measurements equation of calibration dynamic forces transducers by load weight, the main budget uncertainty components of calibration are defined. The new method of dynamic forces transducers calibration with use the reference converter “force-deformation” based on the calibrated elastic element and measurement of his deformation by a laser interferometer is offered. The mathematical model and the main measurements equation of the offered method is constructed. It is shown that use of calibration method based on measurements by the laser interferometer of calibrated elastic element deformations allows to exclude or to considerably reduce the uncertainty budget components inherent to method of load weight.

  11. Biasing of Capacitive Micromachined Ultrasonic Transducers.

    Science.gov (United States)

    Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

    2017-02-01

    Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm 2 ) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

  12. Parameter sensitivity study of a Field II multilayer transducer model on a convex transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2009-01-01

    A multilayer transducer model for predicting a transducer impulse response has in earlier works been developed and combined with the Field II software. This development was tested on current, voltage, and intensity measurements on piezoceramics discs (Bæk et al. IUS 2008) and a convex 128 element...... ultrasound imaging transducer (Bæk et al. ICU 2009). The model benefits from its 1D simplicity and hasshown to give an amplitude error around 1.7‐2 dB. However, any prediction of amplitude, phase, and attenuation of pulses relies on the accuracy of manufacturer supplied material characteristics, which may...... is a quantitative calibrated model for a complete ultrasound system. This includes a sensitivity study aspresented here.Statement of Contribution/MethodsThe study alters 35 different model parameters which describe a 128 element convex transducer from BK Medical Aps. The changes are within ±20 % of the values...

  13. Capacitive pressure transducer using flexible films. Junan film wo mochiita seiden yoryoshiki atsukaku transducer

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y.; Tsuchida, N.; Imai, K. (Toyota Technological Institute, Aichi (Japan)); Fujita, K. (Nitto Denko Corp., Osaka (Japan)): Tsuboi, O. (Fujitsu Corp., Tokyo (Japan))

    1992-12-20

    This paper describes the design, manufacture, and evaluation of a capacitive pressure transducer made of polyimide films. The structure of a pressure transducer cell was first determined, and then, the deflection-stress and capacitance-load characteristics of the surface film were analyzed using finite element methods. For the practical stage of manufacture, a polyimide film was emboss processed and electrodes were deposited on the film to construct a pressure transducer cell to which a Schmidt-trigger detecting circuit was connected. As a consequence of the examination of operational characteristics of the cell, it was found that the actual relation between the deflection and load approximately agreed with the linear analyses, and that the capacitance depended with little hysteresis on the gap regardless of the native visco-elasticity of the film. Furthermore, small stick-slip vibration of a contact rubber surface was detected by the transducer to verify its high sensitivity. 17 refs., 18 figs.

  14. Microhydraulic transducer technology for actuation and power generation

    Science.gov (United States)

    Hagood, Nesbitt W.; Roberts, David C.; Saggere, Laxminarayana; Breuer, Kenneth S.; Chen, Kuo-Shen; Carretero, Jorge A.; Li, Hanqing; Mlcak, Richard; Pulitzer, Seward W.; Schmidt, Martin A.; Spearing, S. Mark; Su, Yu-Hsuan

    2000-06-01

    The paper introduces a novel transducer technology, called the solid-state micro-hydraulic transducer, currently under development at MIT. The new technology is enabled through integration of micromachining technology, piezoelectrics, and microhydraulic concepts. These micro-hydraulic transducers are capable of bi-directional electromechanical energy conversion, i.e., they can operate as both an actuator that supplies high mechanical force in response to electrical input and an energy generator that transduces electrical energy from mechanical energy in the environment. These transducers are capable of transducing energy at very high specific power output in the order of 1 kW/kg, and thus, they have the potential to enable many novel applications. The concept, the design, and the potential applications of the transducers are presented. Present efforts towards the development of these transducers, and the challenges involved therein, are also discussed.

  15. Dissipation in vibrating superleak second sound transducers

    International Nuclear Information System (INIS)

    Giordano, N.

    1985-01-01

    We have performed an experimental study of the generation and detection of second sound in 4 He using vibrating superleak second sound transducers. At temperatures well below T/sub lambda/ and for low driving amplitudes, the magnitude of the generated second sound wave is proportional to the drive amplitude. However, near T/sub lambda/ and for high drive amplitudes this is no longer the case--instead, the second sound amplitude saturates. In this regime we also find that overtones of the drive frequency are generated. Our results suggest that this behavior is due to critical velocity effects in the pores of the superleak in the generator transducer. This type of measurement may prove to be a useful way in which to study critical velocity effects in confined geometries

  16. Ultrasonic transducer design for uniform insonation

    International Nuclear Information System (INIS)

    Harrison, G.H.; Balcer-Kubiczek, E.K.; McCulloch, D.

    1984-01-01

    Techniques used in transducer development for acoustical imaging have been evaluated for the purpose of producing broad, uniform ultrasonic fields from planar radiators. Such fields should be useful in hyperthermia, physical therapy, and ultrasonic bioeffects studies. Fourier inversion of the circ function yielded a source velocity distribution proportional to (P/r) exp ((-ik/2Z) (2Z/sup 2/+r/sup 2/)) J/sub 1/(krP/Z), where r is the radial source coordinate, k is the wave number, and P is the desired radius of uniform insonation at a depth Z in water. This source distribution can be truncated without significantly degrading the solution. A simpler solution consists of exponentially shading the edge of an otherwise uniformly excited disk transducer. This approach was successfully approximated experimentally

  17. Cymbal and BB underwater transducers and arrays

    Energy Technology Data Exchange (ETDEWEB)

    Newnham, R.E.; Zhang, J.; Alkoy, S.; Meyer, R.; Hughes, W.J.; Hladky-Hennion, A.C.; Cochran, J.; Markley, D. [Materials Research Laboratory, Penn State University, University Park, PA 16802 (United States)

    2002-09-01

    The cymbal is a miniaturized class V flextensional transducer that was developed for use as a shallow water sound projector and receiver. Single elements are characterized by high Q, low efficiency, and medium power output capability. Its low cost and thin profile allow the transducer to be assembled into large flexible arrays. Efforts were made to model both single elements and arrays using the ATILA code and the integral equation formulation (EQI).Millimeter size microprobe hydrophones (BBs) have been designed and fabricated from miniature piezoelectric hollow ceramic spheres for underwater applications such as mapping acoustic fields of projectors, and flow noise sensors for complex underwater structures. Green spheres are prepared from soft lead zirconate titanate powders using a coaxial nozzle slurry process. A compact hydrophone with a radially-poled sphere is investigated using inside and outside electrodes. Characterization of these hydrophones is done through measurement of hydrostatic piezoelectric charge coefficients, free field voltage sensitivities and directivity beam patterns. (orig.)

  18. ACT listening test[Active transducers

    Energy Technology Data Exchange (ETDEWEB)

    Agerkvist, F. [Oersted, DTU, Kgs. Lyngby (Denmark); Fenger, L.M. [Bang and Olufsen ICEPower a/s, Kgs. Lyngby (Denmark)

    2004-07-01

    This report describes the series of subjective listening that was performed in order to test the subjective quality of the integration of amplifier and loudspeaker developed in the Active transducer project. The project is a fundamental study of the loss mechanisms in loudspeakers and amplifiers. The project has resulted in new switch mode amplifier topologies with very high audio performance at a very low cost. (BA)

  19. Transducer Analysis and ATILA++ Model Development

    Science.gov (United States)

    2016-10-10

    the behavior of single crystal piezoelectric devices. OBJECTIVES To carry out this effort, a team consisting of ISEN...recording the vibration displacements on the opposite surface of the sample with a second receiving transducer. A software program is used to curve-fit the ...analysis in a loop until the desired quality of fit is achieved. 12 The technique has, in the past, been successfully used to determine

  20. Updated Results of Ultrasonic Transducer Irradiation Test

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Palmer, Joe [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, 38415-3840 (United States); Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert [Pacific Northwest National Laboratory, 902 Battelle Blvd. Richland, WA, 99354 (United States); Chien, Hual-Te [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL, 60439 (United States); Tittmann, Bernhard; Reinhardt, Brian [Pennsylvania State University, 212 Earth and Engr. Sciences Building, University Park, PA, 16802 (United States); Kohse, Gordon [Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, MA 02139 (United States); Rempe, Joy [Rempe and Associates, LLC, 360 Stillwater, Idaho Falls, ID 83404 (United States); Villard, J.F. [Commissariat a l' energie atomique et aux energies alternatives, Centre d' etudes de Cadarache, 13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10{sup 21} n/cm{sup 2}. A multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET-ASI) program also provided initial support for this effort. This irradiation, which started in February 2014, is an instrumented lead test and real-time transducer performance data are collected along with temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to approximately mid-2015. To date, very encouraging results have been attained as several transducers continue to operate under irradiation. (authors)

  1. Passive Mode Carbon Nanotube Underwater Acoustic Transducer

    Science.gov (United States)

    2016-09-20

    Acoustical transducer arrays can reflect a sound signal in reverse to the sender which can be used for echo location devices. [0008] In Jiang...States Patent No. 8,494,187) a sound wave generator is disclosed which includes a carbon nanotube structure and an insulating reinforcement structure... acoustic device that includes an electrode layer and a sound wave generator. The sound wave generator is disposed on a surface of the electrode

  2. Thermoelectric Transducer Using Bio Nano Process

    Science.gov (United States)

    2015-08-01

    Ferritin; Thermal Transducer; Nanoparticle; Ammonium acetate; Separation distance; Debye length . ABSTRACT: As an application to thermos...condition of 10 mM concentration, the Debye length of ferritin is shorter than 3 nm 40 . Comparing it with the DLS results (Fig. 3), the Debye length is...modified PEGs will obstruct additional modification. This effect should strengthen when PEG length becomes longer which means the utilization of

  3. Cooling Acoustic Transducer with Heat Pipes

    Science.gov (United States)

    2009-07-29

    a heat sink. [0009] In Kan et al (United States Patent No. 6,528,909), a spindle motor assembly is disclosed which has a shaft with an integral...heat pipe. The shaft with the integral heat pipe improves the thermal conductively of the shaft and the spindle motor assembly. The shaft includes...Description of the Prior Art [0004] It is known in the art that transducers, designed to project acoustic power, are often limited by the build

  4. Turbine transducer developed for adverse conditions

    International Nuclear Information System (INIS)

    Cooper, D.R.; Edson, J.L.

    1982-01-01

    This paper reviews the latest developments that the Idaho National Engineering Laboratory (INEL) has made on a turbine transducer used in measurement of two-phase flow. It is operated in a modular configuration with a drag transducer to provide mass flow data. Current configurations allow its use in single modules or in multiples to provide flow profile information. The turbine can also provide mass flow data when used with associated instrumentation such as a densitometer. The transducer, which is the product of long investigations and test series, is subject to high vibration loading and high temperatures as well as a borated liquid environment; flow conditions range from all liquid to all steam and from ambient temperatures to over 600 0 F at pressures up to 2200 psi. Graphite bearing and carbide shaft materials were selected to provide corrosion resistance along with mechanical integrity, and resistance to wear. The new turbine design has met all operational requirements in actual use and in extended lifetime tests

  5. Stress Sensors and Signal Transducers in Cyanobacteria

    Science.gov (United States)

    Los, Dmitry A.; Zorina, Anna; Sinetova, Maria; Kryazhov, Sergey; Mironov, Kirill; Zinchenko, Vladislav V.

    2010-01-01

    In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks), 12 genes for serine-threonine protein kinases (Spks), 42 genes for response regulators (Rres), seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress. PMID:22294932

  6. Ultrasonic properties of all-printed piezoelectric polymer transducers

    Science.gov (United States)

    Wagle, Sanat; Decharat, Adit; Bodö, Peter; Melandsø, Frank

    2013-12-01

    The ability of producing ultrasonic transducers from screen-printing has been explored experimentally, through printing and characterization of a large number of transducers. In an all-printed test design, 124 transducers with four different electrode sizes ranging from 1 to 4.9 mm2, were printed layer-by-layer on a high performance polyethyleneimine polymer. Inks from ferroelectric and conductive polymers were applied to the active part of a transducer, to provide a good acoustical match between the individual layers. Ultrasonic characterizations of the transducers done by two independent methods provided a broad-banded frequency response with a maximum response around 100 MHz.

  7. Linear Array Ultrasonic Transducers: Sensitivity and Resolution Study

    International Nuclear Information System (INIS)

    Kramb, V.A.

    2005-01-01

    The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and integrated a fully automated inspection system for the inspection of turbine engines that incorporates linear phased array ultrasonic transducers. Phased array transducers have been successfully implemented into weld and turbine blade root inspections where the defect types are well known and characterized. Embedded defects in aerospace turbine engine components are less well defined, however. In order to determine the applicability of linear arrays to aerospace inspections the sensitivity of array transducers to embedded defects in engine materials must be characterized. In addition, the implementation of array transducers into legacy inspection procedures must take into account any differences in sensitivity between the array transducer and that of the single element transducer currently used. This paper discusses preliminary results in a study that compares the sensitivity of linear array and conventional single element transducers to synthetic hard alpha defects in a titanium alloy

  8. Na, K-ATPase as signaling transducer

    OpenAIRE

    Li, Juan

    2007-01-01

    It is now generally agreed that Na,K-ATPase (NKA), in addition to its role in the maintenance of Na+ and K+ gradients across the cell membrane, is a signal transducer. Our group has identified a novel signaling pathway where NKA interact with IP3R to form a signaling microdomain. Ouabain, a specific ligand of NKA, activates this pathway, triggers slow Ca2+ oscillations and activates NF-κB. In current study, the molecular mechanisms and some important downstream effects of NK...

  9. Manufacturing technologies for ultrasonic transducers in a broad frequency range

    OpenAIRE

    Gebhardt, Sylvia; Hohlfeld, Kai; Günther, Paul; Neubert, Holger

    2018-01-01

    According to the application field, working frequency of ultrasonic transducers needs to be tailored to a certain value. Low frequency ultrasonic transducers with working frequencies of 1 kHz to 1 MHz are especially interesting for sonar applications, whereas high frequency ultrasonic transducers with working frequencies higher than 15 MHz are favorable for high-resolution imaging in biomedical and non-destructive evaluation. Conventional non-destructive testing devices and clinical ultrasoun...

  10. High Temperature Ultrasonic Transducer for Real-time Inspection

    Science.gov (United States)

    Amini, Mohammad Hossein; Sinclair, Anthony N.; Coyle, Thomas W.

    A broadband ultrasonic transducer with a novel porous ceramic backing layer is introduced to operate at 700 °C. 36° Y-cut lithium niobate (LiNbO3) single crystal was selected for the piezoelectric element. By appropriate choice of constituent materials, porosity and pore size, the acoustic impedance and attenuation of a zirconia-based backing layer were optimized. An active brazing alloy with high temperature and chemical stability was selected to bond the transducer layers together. Prototype transducers have been tested at temperatures up to 700 °C. The experiments confirmed that transducer integrity was maintained.

  11. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji; Koizumi, Nozomu

    2012-01-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  12. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji

    2012-12-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  13. Smooth driving of Moessbauer electromechanical transducers

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, A., E-mail: veiga@fisica.unlp.edu.ar; Mayosky, M. A. [Universidad Nacional de La Plata, Facultad de Ingenieria (Argentina); Martinez, N.; Mendoza Zelis, P.; Pasquevich, G. A.; Sanchez, F. H. [Instituto de Fisica La Plata, CONICET (Argentina)

    2011-11-15

    Quality of Moessbauer spectra is strongly related to the performance of source velocity modulator. Traditional electromechanical driving techniques demand hard-edged square or triangular velocity waveforms that introduce long settling times and demand careful driver tuning. For this work, the behavior of commercial velocity transducers and drive units was studied under different working conditions. Different velocity reference waveforms in constant-acceleration, constant-velocity and programmable-velocity techniques were tested. Significant improvement in spectrometer efficiency and accuracy was achieved by replacing triangular and square hard edges with continuous smooth-shaped transitions. A criterion for best waveform selection and synchronization is presented and attainable enhancements are evaluated. In order to fully exploit this driving technique, a compact microprocessor-based architecture is proposed and a suitable data acquisition system implementation is presented. System linearity and efficiency characterization are also shown.

  14. Modeling piezoelectric ultrasonic transducers for physiotherapy

    International Nuclear Information System (INIS)

    Iglesias, E.; Frutos, J. de; Montero de Espinosa, F.

    2015-01-01

    Applications of ultrasound are well known in medical and aesthetic skin and subcutaneous fatty tissue mobilization treatments. The basic transducer used consists of a piezoelectric disk adhered to a metal delay line in capsule shape. The capsule design is critical since the two bonded elements have vibration modes which can cause very inefficient designs and vibration distributions very irregular if they are not properly studied and utilized. This must be known to avoid distributions of heat and sound pressure that could be ineffective or harmful. In this paper, using Finite Element Method and laser interferometric vibrational analysis, it has reached a piston-type solution that allows properly implement sound pressure vibration dose. (Author)

  15. Development of piezoelectric composites for transducers

    Science.gov (United States)

    Safari, A.

    1994-07-01

    For the past decade and a half, many different types of piezoelectric ceramic-polymer composites have been developed intended for transducer applications. These diphasic composites are prepared from non-active polymer, such as epoxy, and piezoelectric ceramic, such as PZT, in the form of filler powders, elongated fibers, multilayer and more complex three-dimensional structures. For the last four years, most of the efforts have been given to producing large area and fine scale PZT fiber composites. In this paper, processing of piezoelectric ceramic-polymer composites with various connectivity patterns are reviewed. Development of fine scale piezoelectric composites by lost mold, injection molding and the relic method are described. Research activities of different groups for preparing large area piezocomposites for hydrophone and actuator applications are briefly reviewed. Initial development of electrostrictive ceramics and composites are also

  16. Design optimization of embedded ultrasonic transducers for concrete structures assessment.

    Science.gov (United States)

    Dumoulin, Cédric; Deraemaeker, Arnaud

    2017-08-01

    In the last decades, the field of structural health monitoring and damage detection has been intensively explored. Active vibration techniques allow to excite structures at high frequency vibrations which are sensitive to small damage. Piezoelectric PZT transducers are perfect candidates for such testing due to their small size, low cost and large bandwidth. Current ultrasonic systems are based on external piezoelectric transducers which need to be placed on two faces of the concrete specimen. The limited accessibility of in-service structures makes such an arrangement often impractical. An alternative is to embed permanently low-cost transducers inside the structure. Such types of transducers have been applied successfully for the in-situ estimation of the P-wave velocity in fresh concrete, and for crack monitoring. Up to now, the design of such transducers was essentially based on trial and error, or in a few cases, on the limitation of the acoustic impedance mismatch between the PZT and concrete. In the present study, we explore the working principles of embedded piezoelectric transducers which are found to be significantly different from external transducers. One of the major challenges concerning embedded transducers is to produce very low cost transducers. We show that a practical way to achieve this imperative is to consider the radial mode of actuation of bulk PZT elements. This is done by developing a simple finite element model of a piezoelectric transducer embedded in an infinite medium. The model is coupled with a multi-objective genetic algorithm which is used to design specific ultrasonic embedded transducers both for hard and fresh concrete monitoring. The results show the efficiency of the approach and a few designs are proposed which are optimal for hard concrete, fresh concrete, or both, in a given frequency band of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. A method for determining losses in magnetostrictive transducers

    Science.gov (United States)

    Krysin, V. N.; Ketlerov, A. S.

    A method for estimating energy losses in magnetostrictive transducers is described. It is shown that domain remagnetization is responsible for the greatest energy loss in magnetostrictive transducers. Energy losses associated with Foucault currents and Joule heat are an order of magnitude less.

  18. Resonant acoustic transducer system for a well drilling string

    Science.gov (United States)

    Nardi, Anthony P.

    1981-01-01

    For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.

  19. Resonant transducers for solid-state plasma density modulation

    Energy Technology Data Exchange (ETDEWEB)

    Hallock, Gary A., E-mail: hallock@ece.utexas.edu [The University of Texas at Austin, Austin, Texas 78701 (United States); Meier, Mark A., E-mail: mark.a.meier@exxonmobil.com [ExxonMobil Upstream Research Company, Houston, Texas 77389 (United States)

    2016-04-15

    We have developed transducers capable of modulating the plasma density and plasma density gradients in indium antimonide. These transducers make use of piezoelectric drivers to excite acoustic pressure resonance at 3λ/2, generating large amplitude standing waves and plasma density modulations. The plasma density has been directly measured using a laser diagnostic. A layered media model shows good agreement with the experimental measurements.

  20. Optimization of ultrasonic tube testing with concentric transducers

    International Nuclear Information System (INIS)

    Dufayet, J.-P.; Gambin, Raymond.

    1978-01-01

    In order to test tubes by ultrasonics without rotation, concentric transducers can be used with conical mirrors to detect transverse defects and with helical shaped mirrors to detect longitudinal defects. Further optimization studies have been carried out in order to bring the system highly operational. The respective advantages brought by the rotating screen or by our especially designed sectorial transducers are discussed [fr

  1. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  2. Design and performance of the drag-disc turbine transducer

    International Nuclear Information System (INIS)

    Averill, R.H.; Goodrich, L.D.; Ford, R.E.

    1979-01-01

    Mass flow rates at the Loss-of-Fluid Test (LOFT) facility, EG and G Idaho, Inc., at the Idaho National Engineering Laboratory, are measured with the drag-disc turbine transducer (DTT). Operational description of the DTT and the developmental effort are discussed. Performance data and experiences with this transducer have been evaluated and are presented in this paper

  3. A mathematical model for transducer working at high temperature

    International Nuclear Information System (INIS)

    Fabre, J.P.

    1974-01-01

    A mathematical model is proposed for a lithium niobate piezoelectric transducer working at high temperature in liquid sodium. The model proposed suitably described the operation of the high temperature transducer presented; it allows the optimization of the efficiency and band-pass [fr

  4. A Force Transducer from a Junk Electronic Balance

    Science.gov (United States)

    Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

    2009-01-01

    It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

  5. Transducer hygiene: comparison of procedures for decontamination of ultrasound transducers and their use in clinical practice.

    Science.gov (United States)

    Häggström, Mikael; Spira, Jack; Edelstam, Greta

    2015-02-01

    To determine whether current hygiene practices are appropriate during sonographic examinations. Five major hospitals in Sweden were investigated with a survey. At each hospital, the departments corresponding to the main types of sonographic examination were chosen. Personnel who were responsible for or acquainted with the local hygiene procedures completed a standardardized questionnaire. The surveys were completed by 25 departments, where the total number of sonographic examinations was approximately 20,000 per month. For transvaginal and transrectal sonographic examinations, the most common method for decontamination of the transducer was barrier protection during the procedure followed by cleansing with alcohol. Latex was the predominant cover material, but one department used polyethylene gloves, and another department used nitrile gloves. Both of these involved transvaginal ultrasonography. In transcutaneous examinations, all hospitals were using alcohol and paper or cloth for decontamination at a minimum. Transesophageal examinations were carried out without barrier protection, and decontamination was performed with an alkylating substance. The hygiene practices appear to be appropriate at most hospitals, but there is a prevalence of transducer cover materials of unacceptable permeability, as well as use of gloves on transducers despite insufficient evidence of safety. © 2015 Wiley Periodicals, Inc.

  6. Design and Development of transducer for IR radiation measurement

    International Nuclear Information System (INIS)

    Pattarachindanuwong, Surat; Poopat, Bovornchoke; Meethong, Wachira

    2003-06-01

    Recently, IR radiation has many important roles such as for plastics industry, food industry and medical instrumentation. The consequence of exposed irradiation objects from IR can be greatly affected by the quantity of IR radiation. Therefore the objectively this research is to design and develop a transducer for IR radiation measurement. By using a quartz halogen lamp as a IR heat source of IR radiation and a thermopile sensor as a transducer. The thermal conductivity of transducer and air flow, were also considered for design and development of transducer. The study shows that the designed transducer can be used and applied in high temperature process, for example, the quality control of welding, the non-contact temperature measurement of drying oven and the testing of IR source in medical therapy device

  7. Transducers for Sound and Vibration - FEM Based Design

    DEFF Research Database (Denmark)

    Liu, Bin

    2001-01-01

    Design of transducers for measurement of vibration (piezoelectric accelerometers) and sound (condenser microphones) is a very labour intensive work. The design work is mostly based on experience and on simple analogies to electrical circuit design. Often a time consuming itterative loop is used......: Specification of the transducer, production of a physical prototype, measurements on the prototype, changed specification of the transducer etc. Furthermore are many transducers made based on customer requirements which also increases the amount of required design work. For these reasons there is a need...... for methods that can reduce the design time consumption and the number of itterations. The present work proposes to use finite element based programs for simulating the behaviour of a transducer with a given set of specifications. A simulation program for accelerometers was developed and has been tested...

  8. Study on electrical impedance matching for broadband ultrasonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon Woo [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Center for Safety Measurement, Daejeon (Korea, Republic of); Baek, Kwang Sae [Elache Co., Busan (Korea, Republic of)

    2017-02-15

    Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of μm) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately 50 Ω to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

  9. Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

    CSIR Research Space (South Africa)

    Loveday, PW

    2006-03-01

    Full Text Available in the waveguide. Piezoelectric patch transducers are frequently employed, by researchers, for exciting waves in beam like structures. Sonar systems frequently make use of resonant transducers, such as sandwich transducers, for acoustic wave generation...

  10. Mechanical Amplifier for a Piezoelectric Transducer

    Science.gov (United States)

    Moore, James; Swain, Mark; Lawson, Peter; Calvet, Robert

    2003-01-01

    A mechanical amplifier has been devised to multiply the stroke of a piezoelectric transducer (PZT) intended for use at liquid helium temperatures. Interferometry holds the key to high angular resolution imaging and astrometry in space. Future space missions that will detect planets around other solar systems and perform detailed studies of the evolution of stars and galaxies will use new interferometers that observe at mid- and far-infrared wavelengths. Phase-measurement interferometry is key to many aspects of astronomical interferometry, and PZTs are ideal modulators for most methods of phase measurement, but primarily at visible wavelengths. At far infrared wavelengths of 150 to 300 m, background noise is a severe problem and all optics must be cooled to about 4 K. Under these conditions, piezos are ill-suited as modulators, because their throw is reduced by as much as a factor of 2, and even a wavelength or two of modulation is beyond their capability. The largest commercially available piezo stacks are about 5 in. (12.7 cm) long and have a throw of about 180 m at room temperature and only 90 m at 4 K. It would seem difficult or impossible to use PZTs for phase measurements in the far infrared were it not for the new mechanical amplifier that was designed and built.

  11. Piezoelectric Nanotube Array for Broadband High-Frequency Ultrasonic Transducer.

    Science.gov (United States)

    Liew, Weng Heng; Yao, Kui; Chen, Shuting; Tay, Francis Eng Hock

    2018-03-01

    Piezoelectric materials are vital in determining ultrasonic transducer and imaging performance as they offer the function for conversion between mechanical and electrical energy. Ultrasonic transducers with high-frequency operation suffer from performance degradation and fabrication difficulty of the demanded piezoelectric materials. Hence, we propose 1-D polymeric piezoelectric nanostructure with controlled nanoscale features to overcome the technical limitations of high-frequency ultrasonic transducers. For the first time, we demonstrate the integration of a well-aligned piezoelectric nanotube array to produce a high-frequency ultrasonic transducer with outstanding performance. We find that nanoconfinement-induced polarization orientation and unique nanotube structure lead to significantly improved piezoelectric and ultrasonic transducing performance over the conventional piezoelectric thin film. A large bandwidth, 126% (-6 dB), is achieved at high center frequency, 108 MHz. Transmission sensitivity of nanotube array is found to be 46% higher than that of the monolithic thin film transducer attributed to the improved electromechanical coupling effectiveness and impedance match. We further demonstrate high-resolution scanning, ultrasonic imaging, and photoacoustic imaging using the obtained nanotube array transducers, which is valuable for biomedical imaging applications in the future.

  12. Bonding and impedance matching of acoustic transducers using silver epoxy.

    Science.gov (United States)

    Son, Kyu Tak; Lee, Chin C

    2012-04-01

    Silver epoxy was selected to bond transducer plates on glass substrates. The properties and thickness of the bonding medium affect the electrical input impedance of the transducer. Thus, the thickness of the silver epoxy bonding layer was used as a design parameter to optimize the structure for the transducer input impedance to match the 50 Ω output impedance of most radio frequency (RF) generators. Simulation and experimental results show that nearly perfect matching is achieved without using any matching circuit. At the matching condition, the transducer operates at a frequency band a little bit below the half-wavelength resonant frequency of the piezoelectric plate. In experiments, lead titanate (PT) piezoelectric plates were employed. Both full-size, 11.5 mm × 2 mm × 0.4 mm, and half-size, 5.75 mm × 2 mm × 0.4 mm, can be well matched using optimal silver epoxy thickness. The transducer assemblies demonstrate high efficiency. The conversion loss from electrical power to acoustic power in soda-lime glass is 4.3 dB. This loss is low considering the fact that the transducers operate at off-resonance by 12%. With proper choice of silver epoxy thickness, the transducer can be matched at the fundamental, the 3rd and 5th harmonic frequencies. This leads to the possible realization of triple-band transducers. Reliability was assessed with thermal cycling test according to Telcordia GR-468-Core recommendation. Of the 30 transducer assemblies tested, none broke until 2900 cycles and 27 have sustained beyond 4050 cycles. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Broadband electrical impedance matching for piezoelectric ultrasound transducers.

    Science.gov (United States)

    Huang, Haiying; Paramo, Daniel

    2011-12-01

    This paper presents a systematic method for designing broadband electrical impedance matching networks for piezoelectric ultrasound transducers. The design process involves three steps: 1) determine the equivalent circuit of the unmatched piezoelectric transducer based on its measured admittance; 2) design a set of impedance matching networks using a computerized Smith chart; and 3) establish the simulation model of the matched transducer to evaluate the gain and bandwidth of the impedance matching networks. The effectiveness of the presented approach is demonstrated through the design, implementation, and characterization of impedance matching networks for a broadband acoustic emission sensor. The impedance matching network improved the power of the acquired signal by 9 times.

  14. USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

    Science.gov (United States)

    Weaver, H.L.; Campbell, G.S.

    1985-01-01

    Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

  15. Reflective array modeling for reflective and directional SAW transducers.

    Science.gov (United States)

    Morgan, D P

    1998-01-01

    This paper presents a new approximate method for analyzing reflective SAW transducers, with much of the convenience of the coupled-mode (COM) method but with better accuracy. Transduction accuracy is obtained by incorporating the accurate electrostatic solution, giving for example correct harmonics, and allowance for electrode width variation, in a simple manner. Results are shown for a single-electrode transducer, Natural SPUDT and DART SPUDT, each using theoretically derived parameters. In contrast to the COM, the RAM can give accurate results for short or withdrawal-weighted transducers and for wide analysis bandwidth.

  16. Ultrasonic Transducer Peak-to-Peak Optical Measurement

    Directory of Open Access Journals (Sweden)

    Pavel Skarvada

    2012-01-01

    Full Text Available Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spectroscopy (EUNS. Parameters of produced mechanical vibration have to been well known for EUNS. Moreover, a monitoring of mechanical vibration frequency shift with a mass load and sample-transducer coupling is important for EUNS measurement.

  17. Electromechanically active polymer transducers: research in Europe

    Science.gov (United States)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

    2013-10-01

    Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial

  18. Active acoustical impedance using distributed electrodynamical transducers.

    Science.gov (United States)

    Collet, M; David, P; Berthillier, M

    2009-02-01

    New miniaturization and integration capabilities available from emerging microelectromechanical system (MEMS) technology will allow silicon-based artificial skins involving thousands of elementary actuators to be developed in the near future. SMART structures combining large arrays of elementary motion pixels coated with macroscopic components are thus being studied so that fundamental properties such as shape, stiffness, and even reflectivity of light and sound could be dynamically adjusted. This paper investigates the acoustic impedance capabilities of a set of distributed transducers connected with a suitable controlling strategy. Research in this domain aims at designing integrated active interfaces with a desired acoustical impedance for reaching an appropriate global acoustical behavior. This generic problem is intrinsically connected with the control of multiphysical systems based on partial differential equations (PDEs) and with the notion of multiscaled physics when a dense array of electromechanical systems (or MEMS) is considered. By using specific techniques based on PDE control theory, a simple boundary control equation capable of annihilating the wave reflections has been built. The obtained strategy is also discretized as a low order time-space operator for experimental implementation by using a dense network of interlaced microphones and loudspeakers. The resulting quasicollocated architecture guarantees robustness and stability margins. This paper aims at showing how a well controlled semidistributed active skin can substantially modify the sound transmissibility or reflectivity of the corresponding homogeneous passive interface. In Sec. IV, numerical and experimental results demonstrate the capabilities of such a method for controlling sound propagation in ducts. Finally, in Sec. V, an energy-based comparison with a classical open-loop strategy underlines the system's efficiency.

  19. Wideband Single Crystal Transducer for Bone Characterization, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS proposes to develop a simple-to-use, launch capable, ultrasound transducer that is capable of producing the necessary bandwidth to accurately determine in vivo...

  20. Phage Pl mutants with altered transducing abilities for Escherichia coli

    International Nuclear Information System (INIS)

    Wall, J.D.; Harriman, P.D.

    1974-01-01

    A search was made for mutants of the coliphage P1 with altered transducing frequencies. A method was developed for the rapid assay of transducing frequencies in single plaques using prophage lambda as the transduced bacterial marker. This procedure selects for mutants altered in their ability to package host DNA. Mutants with 5 to 10 times higher or 10 to 20 times lower frequencies than those of wild-type P1 were found. Not only are the markers used for the detection of the mutants affected, but all other markers are similarly affected (not always to the same extent). One of the high transducing frequency mutants is a suppressible amber, indicating that loss of a function increases P1's ability to package host DNA preferentially. (U.S.)

  1. Thermal properties photonic crystal fiber transducers with ferromagnetic nanoparticles

    Science.gov (United States)

    Przybysz, N.; Marć, P.; Kisielewska, A.; Jaroszewicz, L. R.

    2015-12-01

    The main aim of the research is to design new types of fiber optic transducers based on filled photonic crystal fibers for sensor applications. In our research we propose to use as a filling material nanoparticles' ferrofluids (Fe3O4 NPs). Optical properties of such transducers are studied by measurements of spectral characteristics' changes when transducers are exposed to temperature and magnetic field changes. From synthesized ferrofluid several mixtures with different NPs' concentrations were prepared. Partially filled commercially available photonic crystal fiber LMA 10 (NKT Photonics) was used to design PCF transducers. Their thermo-optic properties were tested in a temperature chamber. Taking into account magnetic properties of synthetized NPs the patch cords based on a partially filled PM 1550 PCF were measured.

  2. Failure Analysis of High-Power Piezoelectric Transducers

    National Research Council Canada - National Science Library

    Gabrielson, T. B

    2005-01-01

    ... and stress in a piezoelectric material. For a transducer operated near resonance, there will be "hot spots" or regions of locally intense stress and electric field that precipitate premature failure...

  3. Piezoelectric textured ceramics: Effective properties and application to ultrasonic transducers.

    Science.gov (United States)

    Levassort, Franck; Pham Thi, Mai; Hemery, Henry; Marechal, Pierre; Tran-Huu-Hue, Louis-Pascal; Lethiecq, Marc

    2006-12-22

    Piezoelectric textured ceramics obtained by homo-template grain growth (HTGG) were recently demonstrated. A simple model with several assumptions has been used to calculate effective parameters of these new materials. Different connectivities have been simulated to show that spatial arrangements between the considered phases have little influence on the effective parameters, even through the 3-0 connectivity delivers the highest electromechanical thickness factor. A transducer based on a textured ceramic sample has been fabricated and characterised to show the efficiency of these piezoelectric materials. Finally, in a single element transducer configuration, simulation shows an improvement of 2 dB sensitivity for a transducer made with textured ceramic in comparison with a similar transducer design based on standard soft PZT (at equivalent bandwidths).

  4. Detection of plane, poorly oriented wide flaws using focused transducers

    International Nuclear Information System (INIS)

    Vadder, D. de; Azou, P.; Bastien, P.; Saglio, R.

    1976-01-01

    The detection of plane, poorly oriented, wide flaws by ultrasonic non destructive testing is distinctly improved when using focused transducers. An increased echo can be obtained crossing the defect limit [fr

  5. Piezoelectric transducer vibrations in a one-dimensional approximation

    CERN Document Server

    Hilke, H J

    1973-01-01

    The theory of piezoelectric transducer vibrations, which may be treated as one-dimensional, is developed in detail for thin discs vibrating in a pure thickness extensional mode. An effort has been made to obtain relations of general validity, which include losses, and which are in a simple explicit form convenient for practical calculations. The behaviour of transducers is discussed with special attention to their characteristics at the two fundamental frequencies, the so-called parallel and series resonances. Several peculiarities occur when transducers are coupled to media with considerably different acoustic impedances. These peculiarities are discussed and illustrated by numerical results for quartz and PZT 4 piezoelectric discs radiating into water, air and liquid hydrogen. The application of the theory to different types of vibrations is briefly illustrated for thin bars vibrating longitudinally. Short discussions are included on compound transducer systems, and on the properties of thin discs as receiv...

  6. Active Metamaterial Based Ultrasonic Guided Wave Transducer System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An active and tunable metamaterial phased array transducer for guided wave mode selection with high intensity per driving channel and with dramatically lower modal...

  7. Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

    KAUST Repository

    Viržonis, Darius; Kodzius, Rimantas; Vanagas, Galius

    2013-01-01

    The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here

  8. Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

    KAUST Repository

    Viržonis, Darius

    2013-10-22

    The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here by presentin

  9. Performance Evaluation of Pressure Transducers for Water Impacts

    Science.gov (United States)

    Vassilakos, Gregory J.; Stegall, David E.; Treadway, Sean

    2012-01-01

    The Orion Multi-Purpose Crew Vehicle is being designed for water landings. In order to benchmark the ability of engineering tools to predict water landing loads, test programs are underway for scale model and full-scale water impacts. These test programs are predicated on the reliable measurement of impact pressure histories. Tests have been performed with a variety of pressure transducers from various manufacturers. Both piezoelectric and piezoresistive devices have been tested. Effects such as thermal shock, pinching of the transducer head, and flushness of the transducer mounting have been studied. Data acquisition issues such as sampling rate and anti-aliasing filtering also have been studied. The response of pressure transducers have been compared side-by-side on an impulse test rig and on a 20-inch diameter hemisphere dropped into a pool of water. The results have identified a range of viable configurations for pressure measurement dependent on the objectives of the test program.

  10. Finite-State Complexity and the Size of Transducers

    Directory of Open Access Journals (Sweden)

    Cristian Calude

    2010-08-01

    Full Text Available Finite-state complexity is a variant of algorithmic information theory obtained by replacing Turing machines with finite transducers. We consider the state-size of transducers needed for minimal descriptions of arbitrary strings and, as our main result, we show that the state-size hierarchy with respect to a standard encoding is infinite. We consider also hierarchies yielded by more general computable encodings.

  11. Test and evaluation of radioactively contaminated transducers and transmitters

    International Nuclear Information System (INIS)

    Strahm, R.C.

    1983-01-01

    People in the nuclear industries face some unique problems when handling, testing, or examining transducers and transmitters that have been radioactively contaminated. Although many people and organizations, including EG and G Idaho, have performed such work for many years, there are no set, structured approaches or procedures. This paper discusses a disciplined laboratory approach to contaminated transducer testing and evaluation, utilizing equipment and facilities developed specifically for this type of work

  12. A theoretical study of cylindrical ultrasound transducers for intracavitary hyperthermia

    International Nuclear Information System (INIS)

    Lin, W.-L.; Fan, W.-C.; Yen, J.-Y.; Chen, Y.-Y.; Shieh, M.-J.

    2000-01-01

    Purpose: The purpose of this paper was to examine the heating patterns and penetration depth when a cylindrical ultrasound transducer is employed for intracavitary hyperthermia treatments. Methods and Materials: The present study employs a simulation program based on a simplified power deposition model for infinitely long cylindrical ultrasound transducers. The ultrasound power in the tissue is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam, and a uniform attenuation for the entire treatment region is also assumed. The distribution of specific absorption rate (SAR) ratio (the ratio of SAR for a point within the tissue to that for a specific point on the cavity surface) is used to determine the heating pattern for a set of given parameters. The parameters considered are the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity. Results: Simulation results show that the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity are the most influential parameters for the distribution of SAR ratio. A low frequency transducer located in a large cavity can produce a much better penetration. The cavity size is the major parameter affecting the penetration depth for a small cavity size, such as interstitial hyperthermia. The heating pattern can also be dramatically changed by the transducer eccentricity and radiating sector. In addition, for a finite length of cylindrical transducer, lower SAR ratio appears in the regions near the applicator's edges. Conclusion: The distribution of SAR ratio indicates the relationship between the treatable region and the parameters if an appropriate threshold of SAR ratio is taken. The findings of the present study comprehend whether or not a tumor is treatable, as well as select the optimal driving frequency, the appropriate cavity size, and the eccentricity of a cylindrical transducer for a specific treatment

  13. Design of a Smart Ultrasonic Transducer for Interconnecting Machine Applications

    Directory of Open Access Journals (Sweden)

    Chang Xu

    2009-06-01

    Full Text Available A high-frequency ultrasonic transducer for copper or gold wire bonding has been designed, analyzed, prototyped and tested. Modeling techniques were used in the design phase and a practical design procedure was established and used. The transducer was decomposed into its elementary components. For each component, an initial design was obtained with simulations using a finite elements model (FEM. Simulated ultrasonic modules were built and characterized experimentally through the Laser Doppler Vibrometer (LDV and electrical resonance spectra. Compared with experimental data, the FEM could be iteratively adjusted and updated. Having achieved a remarkably highly-predictive FEM of the whole transducer, the design parameters could be tuned for the desired applications, then the transducer is fixed on the wire bonder with a complete holder clamping was calculated by the FEM. The approach to mount ultrasonic transducers on wire bonding machines also is of major importance for wire bonding in modern electronic packaging. The presented method can lead to obtaining a nearly complete decoupling clamper design of the transducer to the wire bonder.

  14. DESIGN AND IMPLEMENTATION OF POTENTIOMETER-BASED NONLINEAR TRANSDUCER EMULATOR

    Directory of Open Access Journals (Sweden)

    Sheroz Khan

    2011-05-01

    Full Text Available This work attempts to design and implement in hardware a transducer with a nonlinear response using potentiometer. Potentiometer is regarded as a linear transducer, while a the response of a nonlinear transducer can be treated as a concatenation of linear segments made out of the response curve of an actual nonlinear transducer at the points of inflections being exhibited by the nonlinear curve. Each straight line segment is characterized by its slope and a constant, called the y-intercept, which is ultimately realized by a corresponding electronic circuit. The complete circuit diagram is made of three stages: (i the input stage for range selection, (ii a digital logic to make appropriate selection, (iii a conditioning circuit for realizing a given straight-line segment identified by its relevant slope and reference voltage. The simulation of the circuit is carried using MULTISIM, and the designed circuit is afterward tested to verify that variations of the input voltage give us an output voltage very close to the response pattern envisaged in the analytical stage of the design. The utility of this work lies in its applications in emulating purpose built transducers that could be used to nicely emulate a transducer in a real world system that is to be controlled by a programmable digital system.

  15. Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

    Directory of Open Access Journals (Sweden)

    Tobias J. R. Eriksson

    2016-08-01

    Full Text Available Three designs for electrodynamic flexural transducers (EDFT for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio ( SNR ≃ 15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart.

  16. Damage detection in concrete structures with smart piezoceramic transducers

    Science.gov (United States)

    Naidu, Akshay S. K.; Bhalla, Suresh

    2003-10-01

    Detection of damages and progressive deterioration in structures is a critical issue. Visual inspections are tedious and unreliable. Incipient damages are often not discernible by low frequency dynamic response and other NDE techniques. Smart piezoelectric ceramic (PZT) transducers are emerging as an effective alternative in health monitoring of structures. The electro-mechanical impedance method employs the self-actuating and sensing characteristics of the PZT, without having to use actuators and sensors separately. When excited by an ac source, the PZT transducers bonded to the host structure activates the higher modes of vibration locally. Changes in the admittance response of the transducer serves as an indicator of damage around the transducer. In this paper, the effectiveness of PZT transducers for characterizing damages in concrete, in terms of the damage extent and location, is experimentally examined. The root mean square deviation (RMSD) index, adopted to quantify the changes in the admittance signatures, correlates with the damage extent. The damages on the surface that is not mounted by the PZT are also discernible. An array of transducers proves effective in detecting the damaged zone. The progressive incipient crack can be detected much before it actually becomes visible to the naked eye.

  17. Home Automation System Based on Intelligent Transducer Enablers

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M.; Dapena, Adriana; González-López, Miguel

    2016-01-01

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet. PMID:27690031

  18. Home Automation System Based on Intelligent Transducer Enablers.

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M; Dapena, Adriana; González-López, Miguel

    2016-09-28

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  19. Home Automation System Based on Intelligent Transducer Enablers

    Directory of Open Access Journals (Sweden)

    Manuel Suárez-Albela

    2016-09-01

    Full Text Available This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers, which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  20. Software for Correcting the Dynamic Error of Force Transducers

    Directory of Open Access Journals (Sweden)

    Naoki Miyashita

    2014-07-01

    Full Text Available Software which corrects the dynamic error of force transducers in impact force measurements using their own output signal has been developed. The software corrects the output waveform of the transducers using the output waveform itself, estimates its uncertainty and displays the results. In the experiment, the dynamic error of three transducers of the same model are evaluated using the Levitation Mass Method (LMM, in which the impact forces applied to the transducers are accurately determined as the inertial force of the moving part of the aerostatic linear bearing. The parameters for correcting the dynamic error are determined from the results of one set of impact measurements of one transducer. Then, the validity of the obtained parameters is evaluated using the results of the other sets of measurements of all the three transducers. The uncertainties in the uncorrected force and those in the corrected force are also estimated. If manufacturers determine the correction parameters for each model using the proposed method, and provide the software with the parameters corresponding to each model, then users can obtain the waveform corrected against dynamic error and its uncertainty. The present status and the future prospects of the developed software are discussed in this paper.

  1. Receive-Noise Analysis of Capacitive Micromachined Ultrasonic Transducers.

    Science.gov (United States)

    Bozkurt, Ayhan; Yaralioglu, G Goksenin

    2016-11-01

    This paper presents an analysis of thermal (Johnson) noise received from the radiation medium by otherwise noiseless capacitive micromachined ultrasonic transducer (CMUT) membranes operating in their fundamental resonance mode. Determination of thermal noise received by multiple numbers of transducers or a transducer array requires the assessment of cross-coupling through the radiation medium, as well as the self-radiation impedance of the individual transducer. We show that the total thermal noise received by the cells of a CMUT has insignificant correlation, and is independent of the radiation impedance, but is only determined by the mass of each membrane and the electromechanical transformer ratio. The proof is based on the analytical derivations for a simple transducer with two cells, and extended to transducers with numerous cells using circuit simulators. We used a first-order model, which incorporates the fundamental resonance of the CMUT. Noise power is calculated by integrating over the entire spectrum; hence, the presented figures are an upper bound for the noise. The presented analyses are valid for a transimpedance amplifier in the receive path. We use the analysis results to calculate the minimum detectable pressure of a CMUT. We also provide an analysis based on the experimental data to show that output noise power is limited by and comparable to the theoretical upper limit.

  2. High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

    Directory of Open Access Journals (Sweden)

    Mihai Valentin Predoi

    2014-01-01

    Full Text Available Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.

  3. Development and research of in-core transducers at IAE (Institute of Atomic Energy)

    International Nuclear Information System (INIS)

    Huang Yucai; Qian Shunfa; Jia Guozhen

    1989-10-01

    The development of in-core transducers at IAE (Institute of Atomic Energy) and their applications in in-pile fuel assembly test are mentioned. These transducers include mainly tubed tungsten-rhenium thermocouple assembly, displacement transducer of linear variable differential transformer, pressure transducer of membrane type, gamma thermometer, turbine flow meter, self-powered neutron detector etc

  4. Immersion apparatus and process for an ultrasonic transducer in a liquid metal

    International Nuclear Information System (INIS)

    Le Baud, P.

    1987-01-01

    The ultrasonic transducer is introduced in a casing. The coupling zone of the transducer is covered by a layer of liquid metal. This layer is solidified and then the transducer with his coating layer is introduced in the liquid metal under an inert atmosphere. The device for immersing the transducer is claimed [fr

  5. Design of a saturated analogue and digital current transducer

    International Nuclear Information System (INIS)

    Pross, Alexander

    2002-01-01

    This project describes the development of a new analogue and digital current transducer, providing a range of new theoretical design methods for these novel devices. The main control feature is the limit cycling operation, and the novel use of the embedded sigma-delta modulator sensor structure to derive a low component count digital sensor. The research programme was initiated into the design, development and evaluation of a novel non-Hall sensing analogue and digital current transducer. These transducers are used for measurement of high currents in power systems applications. The investigation is concerned with a new design which uses a magnetic ferrite core without an air gap for current measurement. The motivation for this work was to design a new control circuit which provides a low component count, and utilises the non-linear properties of the magnetic ferrite core to transmit direct current. The use of a limit cycle control circuit was believed to be particularly suitable for the analogue and digital transducers, for two main reasons: the low component count, and the output signal is directly digital. In line with the motivations outlined above, the outcome of the research has witnessed the design, development and evaluation of a practically realisable analogue and digital current transducer. The design procedure, which is documented in this thesis, is considered to be a major contribution to the field of transducers design and development using a control systems approach. Mathematical models for both analogue and digital transducers were developed and the resulting model based predictions were found to be in good agreement with measured results. Simplification of the new model sensing device was achieved by approximating the non-linear ferrite core using FFT analysis. This is also considered to be a significant contribution. The development analogue and digital current censors employed a sampled data control systems design and utilised limit cycling

  6. Multiple single-element transducer photoacoustic computed tomography system

    Science.gov (United States)

    Kalva, Sandeep Kumar; Hui, Zhe Zhi; Pramanik, Manojit

    2018-02-01

    Light absorption by the chromophores (hemoglobin, melanin, water etc.) present in any biological tissue results in local temperature rise. This rise in temperature results in generation of pressure waves due to the thermoelastic expansion of the tissue. In a circular scanning photoacoustic computed tomography (PACT) system, these pressure waves can be detected using a single-element ultrasound transducer (SUST) (while rotating in full 360° around the sample) or using a circular array transducer. SUST takes several minutes to acquire the PA data around the sample whereas the circular array transducer takes only a fraction of seconds. Hence, for real time imaging circular array transducers are preferred. However, these circular array transducers are custom made, expensive and not easily available in the market whereas SUSTs are cheap and readily available in the market. Using SUST for PACT systems is still cost effective. In order to reduce the scanning time to few seconds instead of using single SUST (rotating 360° ), multiple SUSTs can be used at the same time to acquire the PA data. This will reduce the scanning time by two-fold in case of two SUSTs (rotating 180° ) or by four-fold and eight-fold in case of four SUSTs (rotating 90° ) and eight SUSTs (rotating 45° ) respectively. Here we show that with multiple SUSTs, similar PA images (numerical and experimental phantom data) can be obtained as that of PA images obtained using single SUST.

  7. A piezoelectric transducer for measurement of dynamic strain in pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lannes, Daniel P.; Gama, Antonio L. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

    2009-07-01

    This work presents a new strain transducer developed mainly for the inspection and evaluation of piping systems with excessive vibration. Vibration is one of the most common causes of piping failures. These failures could be avoided if the vibration problems were identified and quickly evaluated. Procedures for evaluation of piping vibration are usually based on pipe velocity or displacement. Although simple and fast, these procedures do not provide precise information on the risk of piping fatigue failure. Through the measurement of pipe dynamic strains the risk of failure due to vibration can be determined more accurately. The measurement of strain is usually performed using the conventional strain gauge method. Although efficient and accurate, the implementation of the conventional strain gauge technique may become a difficult task in certain industrial scenarios. Motivated by the need of a simple and rapid method for pipe dynamic strain measurement, a piezoelectric dynamic strain transducer was developed. This work presents a description of the piezoelectric strain transducer and the preliminary results of pipe strain measurements. The transducer can be applied directly to the pipe through magnetic bases allowing for the quick measurement of the dynamic strains in many points of the pipe. The transducer signal can be read with the same commercial data collectors used for accelerometers. (author)

  8. Transducer selection and application in magnetoacoustic tomography with magnetic induction

    International Nuclear Information System (INIS)

    Zhou, Yuqi; Wang, Jiawei; Ma, Qingyu; Sun, Xiaodong; Zhang, Dong

    2016-01-01

    As an acoustic receiver, transducer plays a vital role in signal acquisition and image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). In order to optimize signal acquisition, the expressions of acoustic pressure detection and waveform collection are theoretically studied based on the radiation theory of acoustic dipole and the reception pattern of transducer. Pressure distributions are simulated for a cylindrical phantom model using a planar piston transducer with different radii and bandwidths. The proposed theory is also verified by the experimental measurements of acoustic waveform detection for an aluminum foil cylinder. It is proved that acoustic pressure with sharp and clear boundary peaks can be detected by the large-radius transducer with wide bandwidth, reflecting the differential of the induced Lorentz force accurately, which is helpful for precise conductivity reconstruction. To detect acoustic pressure with acceptable pressure amplitude, peak pressure ratio, amplitude ratio, and improved signal to noise ratio, the scanning radius of 5–10 times the radius of the object should be selected to improve the accuracy of image reconstruction. This study provides a theoretical and experimental basis for transducer selection and application in MAT-MI to obtain reconstructed images with improved resolution and definition.

  9. Transducer selection and application in magnetoacoustic tomography with magnetic induction

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yuqi; Wang, Jiawei; Ma, Qingyu, E-mail: maqingyu@njnu.edu.cn [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023 (China); Sun, Xiaodong [China Key System & Integrated Circuit Co., Ltd., Wuxi 214072 (China); Zhang, Dong [Laboratory of Modern Acoustics of MOE, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)

    2016-03-07

    As an acoustic receiver, transducer plays a vital role in signal acquisition and image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). In order to optimize signal acquisition, the expressions of acoustic pressure detection and waveform collection are theoretically studied based on the radiation theory of acoustic dipole and the reception pattern of transducer. Pressure distributions are simulated for a cylindrical phantom model using a planar piston transducer with different radii and bandwidths. The proposed theory is also verified by the experimental measurements of acoustic waveform detection for an aluminum foil cylinder. It is proved that acoustic pressure with sharp and clear boundary peaks can be detected by the large-radius transducer with wide bandwidth, reflecting the differential of the induced Lorentz force accurately, which is helpful for precise conductivity reconstruction. To detect acoustic pressure with acceptable pressure amplitude, peak pressure ratio, amplitude ratio, and improved signal to noise ratio, the scanning radius of 5–10 times the radius of the object should be selected to improve the accuracy of image reconstruction. This study provides a theoretical and experimental basis for transducer selection and application in MAT-MI to obtain reconstructed images with improved resolution and definition.

  10. Piezoelectric Polymer Ultrasound Transducers and Its Biomedical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kang Lyeol; Cao, Yanggang [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

    2012-10-15

    PVDF(poly vinylidene fluoride) and P(VDF-TrFE)(poly vinylidene fluoride-tetrafluoroethylene) are the typical piezoelectric polymers with unique properties. Even they are inferior to conventional piezoelectric ceramics PZT in electromechanical conversion efficiency and interior loss, though they are superior in receiving sensitivity and frequency bandwidth. Their acoustic impedances are relatively close to water or biological tissue and it is easier to make thin film than other piezoelectric materials. Furthermore, the film is so flexible that it is easy to attach on a complex surface. Those properties are suitable for the ultrasound transducers which are useful for medical and biological application, so that various types of polymer transducers have been developed. In this paper, several important considerations for design and fabrication of piezoelectric polymer transducers were described and their effect on the transducer performance were demonstrated through the KLM model analysis. Then, it was briefly reviewed about the structures of the polymer transducers developed for obtaining images as well as the characteristics of the images in several important medical and biological application fields.

  11. A new hybrid longitudinal–torsional magnetostrictive ultrasonic transducer

    International Nuclear Information System (INIS)

    Karafi, Mohammad Reza; Hojjat, Yousef; Sassani, Farrokh

    2013-01-01

    In this paper, a novel hybrid longitudinal–torsional magnetostrictive ultrasonic transducer (HL–TMUT) is introduced. The transducer is composed of a magnetostrictive exponential horn and a stainless steel tail mass. In this transducer a spiral magnetic field made up of longitudinal and circumferential magnetic fields is applied to the magnetostrictive horn. As a result, the magnetostrictive horn oscillates simultaneously both longitudinally and torsionally in accordance with the Joule and Wiedemann effects. The magnetostrictive exponential horn is designed in such a manner that it has the same longitudinal and torsional resonant frequency. It is made up of ‘2V Permendur’, which has isotropic magnetic properties. The differential equations of the torsional and longitudinal vibration of the horn are derived, and a HL–TMUT is designed with a resonant frequency of 20 573 Hz. The natural frequency and mode shapes of the transducer are considered theoretically and numerically. The experimental results show that this transducer resonates torsionally and longitudinally with frequencies of 20 610 Hz and 20 830 Hz respectively. The maximum torsional displacement is 1.5 mrad m −1 and the maximum longitudinal displacement is 0.6 μm. These are promising features for industrial applications. (paper)

  12. Design of compact piezoelectric transducers for shock wave applications

    Science.gov (United States)

    Dreyer, Thomas; Liebler, Marko; Riedlinger, Rainer E.; Ginter, Siegfried

    2003-10-01

    The application of focused intense sound pulses to treat several orthopedic diseases has gained in importance during the past years. Self-focusing piezoelectric transducers known from ESWL are not well suited for this purpose due to their size. Therefore compact transducers have to be designed. This implies an increase of the pressure pulse amplitude generated at the radiating surface. A stacked placement of two piezoelectric layers driven by two high-voltage pulses with an adjustable delay accomplishes this. Several designs are presented here representing transducers of different sizes. In principle piezoelectric transducers have the ability to vary the pressure pulse shape to a wider extent than other shock wave sources. Based on FEM simulations of the transducer the influence of some driving parameters, like a variation of the interpulse delay or shape of the driving voltage, on the resulting focal pressure signal is demonstrated. The results show the feasibility to control some parameters of the signal, for example the peak negative pressure amplitude. This possibility could provide new aspects in basic research as well as in clinical applications.

  13. Design of HIFU Transducers for Generating Specified Nonlinear Ultrasound Fields.

    Science.gov (United States)

    Rosnitskiy, Pavel B; Yuldashev, Petr V; Sapozhnikov, Oleg A; Maxwell, Adam D; Kreider, Wayne; Bailey, Michael R; Khokhlova, Vera A

    2017-02-01

    Various clinical applications of high-intensity focused ultrasound have different requirements for the pressure levels and degree of nonlinear waveform distortion at the focus. The goal of this paper is to determine transducer design parameters that produce either a specified shock amplitude in the focal waveform or specified peak pressures while still maintaining quasi-linear conditions at the focus. Multiparametric nonlinear modeling based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation with an equivalent source boundary condition was employed. Peak pressures, shock amplitudes at the focus, and corresponding source outputs were determined for different transducer geometries and levels of nonlinear distortion. The results are presented in terms of the parameters of an equivalent single-element spherically shaped transducer. The accuracy of the method and its applicability to cases of strongly focused transducers were validated by comparing the KZK modeling data with measurements and nonlinear full diffraction simulations for a single-element source and arrays with 7 and 256 elements. The results provide look-up data for evaluating nonlinear distortions at the focus of existing therapeutic systems as well as for guiding the design of new transducers that generate specified nonlinear fields.

  14. Electromechanical characteristics of discal piezoelectric transducers with spiral interdigitated electrodes

    International Nuclear Information System (INIS)

    Pan, Chengliang; Xiao, Guangjun; Feng, Zhihua; Liao, Wei-Hsin

    2014-01-01

    In this study, piezoceramic thin disks with spiral interdigitated electrodes on their surfaces are proposed to generate in-plane torsional vibrations. Electromechanical characteristics of the discal piezoelectric transducers are investigated. Working principles of the transducers are explained while their static deformations are formulated. Dynamic models are derived to analyze the in-plane torsional vibrations of the disks together with the radial vibrations. The corresponding electromechanical equivalent circuits are also obtained. With different boundary conditions and structural parameters, frequency responses of their electric admittances are calculated numerically. Resonant frequencies, mode shapes, and electromechanical coupling coefficients of the vibration modes are also extracted. Prototype transducers are fabricated and tested to validate the theoretical results. (paper)

  15. Inspection of complex geometry pieces with an intelligent contact transducer

    International Nuclear Information System (INIS)

    Chatillon, S.; Roy, O.; Mahaut, St.

    2000-01-01

    A new multi-element contact transducer has been developed to improve the inspection of components with complex geometry. The emitting surface is flexible in order to optimize the contact with pieces. An algorithm, based on a simplified geometric model, has been used to determine the delays law which allows to control the focal characteristics of the transmitted field. Acquisition data lead in transmission with an articulated transducer validate the behavior provided by simulation. Thus the optimization of the delays law ensures the transmission of a beam which is homogeneous and controlled during the moving of the transducer. Inspections in echo-pulse mode are implemented on a sample simulating a component controlled on site. Results show that the dynamical adaptation of the delays law to the geometry of the piece leads to very good performances

  16. Actuators, transducers and motors based on giant magnetostrictive materials

    Energy Technology Data Exchange (ETDEWEB)

    Claeyssen, F.; Lhermet, N.; Le Letty, R. [Cedrat Recherche, Meylan (France); Bouchilloux, P. [Magsoft Corporation, 1223 People`s Avenue, New York 12180 (United States)

    1997-08-01

    Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature ``giant`` magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported. These strains permit building various actuating devices (actuators, transducers, motors) both at macro and micro scale. The object of the paper is to recall adapted design methods, especially finite element methods such as ATILA, and to review these different kinds of devices studied at Cedrat Recherche, providing both up-dated experimental and numerical results. The presented devices will include several large displacement longitudinal and shear actuators biased using permanent magnets and used either as characterisation devices or as electromechanical actuators (for active damping, for sonar transducers..), a 1 kHz 4 kW Tonpilz-type sonar transducer called the tripode, a 2 N m torque rotating multi-mode motor, a torsion based drift free micro actuator and a wireless linear micromotor. (orig.)

  17. Torque magnetometry by use of capacitance type transducer

    International Nuclear Information System (INIS)

    Braught, M.C.; Pechan, M.J.

    1992-01-01

    Interfacial anisotropy in magnetic multilayered samples comprised of nanometer thick magnetic layers alternating with non-magnetic layers is investigated by torque magnetometry in the temperature regime of 4 to 300K. The design, construction and use of a capacitance type transducer wherein the sample is mounted directly on with the plate of the capacitor, will be described. As a result the sample and transducer spatially coexist at the sample temperature in an applied external field, eliminating mechanical coupling from the cryogenic region to a remote room temperature transducer. The capacitor measuring the torque of the sample is paired with a reference capacitor. The difference between torque influenced capacitance and the reference is then determined by a differential transimpedance amplifier. Since both capacitors are physically identical variables such as temperature, vibration, orientation and external devices are minimized. Torques up to 300 dyne-cm can be measured with a sensitivity of 0.010 dyne-cm

  18. A novel serrated columnar phased array ultrasonic transducer

    Science.gov (United States)

    Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

    2016-02-01

    Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

  19. INFLUENCE OF PIEZOELECTRIC TRANSDUCER TO GLASS FIBER REINFORCED COMPOSITE STIFFNESS

    Directory of Open Access Journals (Sweden)

    Witold Rządkowski

    2015-08-01

    Full Text Available The main goal was to determine if transducers based on piezoelectric materials are suitable for strain calculations in thin GFRP specimens. Numerous experimental studies, both physical and numerical, performed by the authors, have shown that there is a huge influence of bonded piezoelectric transducer on the overall stiffness of the measured object. The paper presents tensile test performed on strength machine with Digital Image Correlation strain and deflection observations. Test were compared with FEM models for detailed investigation. The main conclusion is piezoelectric transducers has huge influence on local stiffness of measured object. That is critical especially when they are used as strain sensors, when presence of sensor is influencing to measured results.

  20. Investigation of Calibrating Force Transducer Using Sinusoidal Force

    International Nuclear Information System (INIS)

    Zhang Li; Wang Yu; Zhang Lizhe

    2010-01-01

    Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

  1. Measurement of two-phase flow momentum with force transducers

    International Nuclear Information System (INIS)

    Hardy, J.E.; Smith, J.E.

    1990-01-01

    Two strain-gage-based drag transducers were developed to measure two-phase flow in simulated pressurized water reactor (PWR) test facilities. One transducer, a drag body (DB), was designed to measure the bidirectional average momentum flux passing through an end box. The second drag sensor, a break through detector (BTD), was designed to sense liquid downflow from the upper plenum to the core region. After prototype sensors passed numerous acceptance tests, transducers were fabricated and installed in two experimental test facilities, one in Japan and one in West Germany. High-quality data were extracted from both the DBs and BTDs for a variety of loss-of-coolant accident (LOCA) scenarios. The information collected from these sensors has added to the understanding of the thermohydraulic phenomena that occur during the refill/reflood stage of a LOCA in a PWR. 9 refs., 15 figs

  2. A new ultrasonic transducer for improved contrast nonlinear imaging

    International Nuclear Information System (INIS)

    Bouakaz, Ayache; Cate, Folkert ten; Jong, Nico de

    2004-01-01

    Second harmonic imaging has provided significant improvement in contrast detection over fundamental imaging. This improvement is a result of a higher contrast-to-tissue ratio (CTR) achievable at the second harmonic frequency. Nevertheless, the differentiation between contrast and tissue at the second harmonic frequency is still in many situations cumbersome and contrast detection remains nowadays as one of the main challenges, especially in the capillaries. The reduced CTR is mainly caused by the generation of second harmonic energy from nonlinear propagation effects in tissue, which hence obscures the echoes from contrast bubbles. In a previous study, we demonstrated theoretically that the CTR increases with the harmonic number. Therefore the purpose of our study was to increase the CTR by selectively looking to the higher harmonic frequencies. In order to be able to receive these high frequency components (third up to the fifth harmonic), a new ultrasonic phased array transducer has been constructed. The main advantage of the new design is its wide frequency bandwidth. The new array transducer contains two different types of elements arranged in an interleaved pattern (odd and even elements). This design enables separate transmission and reception modes. The odd elements operate at 2.8 MHz and 80% bandwidth, whereas the even elements have a centre frequency of 900 kHz with a bandwidth of 50%. The probe is connected to a Vivid 5 system (GE-Vingmed) and proper software is developed for driving. The total bandwidth of such a transducer is estimated to be more than 150% which enables higher harmonic imaging at an adequate sensitivity and signal to noise ratio compared to standard medical array transducers. We describe in this paper the design and fabrication of the array transducer. Moreover its acoustic properties are measured and its performances for nonlinear contrast imaging are evaluated in vitro and in vivo. The preliminary results demonstrate the advantages of

  3. Transducers for the Brazilian gravitational wave detector 'Mario Schenberg'

    International Nuclear Information System (INIS)

    Frajuca, Carlos; Ribeiro, Kilder L; Andrade, Luiz A; Jr, Walter F Velloso; Melo, Jose L; Aguiar, Odylio D; Magalhaes, Nadja S

    2002-01-01

    'Mario Schenberg' is a spherical resonant-mass gravitational wave (GW) detector that will be part of a GW detection array of three detectors. The other two will be built in Italy and the Netherlands. Their resonant frequencies will be around 3.2 kHz with a bandwidth of about 200 Hz. This range of frequencies is new in a field where the typical frequencies lie below 1 kHz, making the transducer development much more complex. In this paper, the design of the mechanical part of the transducer will be shown, as well as the attachment method to the sphere and the expected sensitivity

  4. A digital transducer and digital microphone using an optical technique

    Science.gov (United States)

    Ghelmansarai, F. A.

    1996-09-01

    A transducer is devised to measure pressure, displacements or angles by optical means. This transducer delivers a digital output without relying on interferometry techniques or analogue-to-digital converters. This device is based on an optical scanner and an optical detector. An inter-digital photoconductive detector (IDPC) is employed that delivers a series of pulses, whose number depends on the scan length. A pre-objective scanning configuration is used that allows for the possibility of a flat image plane. The optical scanner provides scanning of IDPC and the generated scan length is proportional to the measurand.

  5. An overview of the dynamic calibration of piezoelectric pressure transducers

    Science.gov (United States)

    Theodoro, F. R. F.; Reis, M. L. C. C.; d’ Souto, C.

    2018-03-01

    Dynamic calibration is a research area that is still under development and is of great interest to aerospace and automotive industries. This study discusses some concepts regarding dynamic measurements of pressure quantities and presents an overview of dynamic calibration of pressure transducers. Studies conducted by the Institute of Aeronautics and Space focusing on research regarding piezoelectric pressure transducer calibration in shock tube are presented. We employed the Guide to the Expression of Uncertainty and a Monte Carlo Method in the methodology. The results show that both device and methodology employed are adequate to calibrate the piezoelectric sensor.

  6. Thermal energy harvesters with piezoelectric or electrostatic transducer

    Science.gov (United States)

    Prokaryn, Piotr; Domański, Krzysztof; Marchewka, Michał; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

    2014-08-01

    This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

  7. Analysis of eigenfrequencies in piezoelectric transducers using the finite element method

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1988-01-01

    transducers, which include the complete set of piezoelectric equations, have been included. They can find eigenfrequencies for undamped transducers and perform forced-response analysis for transducers with internal and radiation damping. The superelement technique is used to model the transducer backing......It is noted that the finite-element method is a valuable supplement to the traditional methods for design of novel transducer types because it can determine the vibrational pattern of piezoelectric transducers and is applicable to any geometry. Computer programs for analysis of axisymmetric...

  8. Determination of the response time of pressure transducers using the direct method

    International Nuclear Information System (INIS)

    Perillo, S.R.P.

    1994-01-01

    The available methods to determine the response time of nuclear safety related pressure transducers are discussed, with emphasis to the direct method. In order to perform the experiments, a Hydraulic Ramp Generator was built. The equipment produces ramp pressure transients simultaneously to a reference transducer and to the transducer under test. The time lag between the output of the two transducers, when they reach a predetermined setpoint, is measured as the time delay of the transducer under test. Some results using the direct method to determine the time delay of pressure transducers (1 E Class Conventional) are presented. (author). 18 refs, 35 figs, 12 tabs

  9. Wall thickness tests by means of rotating electrodynamic transducers

    International Nuclear Information System (INIS)

    Hueschelrath, G.

    1986-01-01

    For about three years, the EROT system has been employed for measuring wall thicknesses on pipes of ferritic steels. The experience gathered and the degree of reliability reached up to now are definitely encouraging, so that an increased use of electrodynamic transducers can be expected for measuring pipes with outside diameters of up to 22 inches. (orig.) [de

  10. A New High-Temperature Ultrasonic Transducer for Continuous Inspection.

    Science.gov (United States)

    Amini, Mohammad Hossein; Sinclair, Anthony N; Coyle, Thomas W

    2016-03-01

    A novel design of piezoelectric ultrasonic transducer is introduced, suitable for operation at temperatures of up to 700 °C-800 °C. Lithium niobate single crystal is chosen as the piezoelectric element primarily due to the high Curie temperature of 1200 °C. A backing element based on a porous ceramic is designed for which the pore volume fraction and average pore diameter in the ceramic matrix can be controlled in the manufacturing process; this enables the acoustic impedance and attenuation to be selected to match their optimal values as predicted by a one-dimensional transducer model of the entire transducer. Porous zirconia is selected as the ceramic matrix material of the backing element to obtain an ultrasonic signal with center frequency of 2.7-3 MHz, and 3-dB bandwidth of 90%-95% at the targeted operating temperature. Acoustic coupling of the piezocrystal to the backing element and matching layer is investigated using commercially available high-temperature adhesives and brazing alloys. The performance of the transducer as a function of temperature is studied. Stable bonding and clear signals were obtained using an aluminum brazing alloy as the bonding agent.

  11. Universal Quantum Transducers Based on Surface Acoustic Waves

    NARCIS (Netherlands)

    Schuetz, M.J.A.; Kessler, E.M.; Giedke, G.; Vandersypen, L.M.K.; Lukin, M.D.; Cirac, J.I.

    2015-01-01

    We propose a universal, on-chip quantum transducer based on surface acoustic waves in piezoactive materials. Because of the intrinsic piezoelectric (and/or magnetostrictive) properties of the material, our approach provides a universal platform capable of coherently linking a broad array of qubits,

  12. Instantaneous input electrical power measurements of HITU transducer

    Energy Technology Data Exchange (ETDEWEB)

    Karaboece, B; Guelmez, Y [Tuebitak Ulusal Metroloji Enstituesue (UME), P.K. 54 41470 Gebze-Kocaeli (Turkey); Rajagapol, S; Shaw, A, E-mail: baki.karaboce@ume.tubitak.gov.t [National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW (United Kingdom)

    2011-02-01

    HITU (High Intensity Theraupetic Ultrasound) transducers are widely used in therapeutic ultrasound in medicine. The output ultrasonic power of HITU transducer can be measured in number of methods described in IEC 61161 standard [1]. New IEC standards specifically for measurement of HITU equipment are under development. The ultrasound power radiated from a transducer is dependent on applied input electrical voltage and current and consequently power. But, up to now, no standardised method has been developed and adopted for the input electrical power measurements. Hence, a workpackage was carried out for the establishment of such method in the frequency range of 1 to 3 MHz as a part of EURAMET EMRP Era-net plus 'External Beam Cancer Therapy' project. Several current shunts were developed and evaluated. Current measurements were also realized with Philips current probe and preamplifier at NPL and Agilent current probe at UME. In this paper, a method for the measurement of instantaneous electrical power delivered to a reactive ultrasound transducer in the required frequency range is explored.

  13. Neutron Irradiation Tests of Pressure Transducers in Liquid Helium

    CERN Document Server

    Amand, J F; Casas-Cubillos, J; Thermeau, J P

    1999-01-01

    The superconducting magnets of the future Large Hadron Collider (LHC) at CERN will operate in pressurised superfluid helium (1 bar, 1.9 K). About 500 pressure transducers will be placed in the liquid helium bath for monitoring the filling and the pressure transients after resistive transitions. Their precision must remain better than 100 mbar at pressures below 2 bar and better than 5% for higher pressures (up to 20 bar), with temperatures ranging from 1.8 K to 300 K. All the tested transducers are based on the same principle: the fluid or gas is separated from a sealed reference vacuum by an elastic membrane; its deformation indicates the pressure. The transducers will be exposed to high neutron fluence (2 kGy, 1014 n/cm2 per year) during the 20 years of machine operation. This irradiation may induce changes both on the membranes characteristics (leakage, modification of elasticity) and on gauges which measure their deformations. To investigate these effects and select the transducer to be used in the LHC, a...

  14. Nonlinear Dynamic Modeling of Langevin-Type Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Nicolás Peréz Alvarez

    2015-11-01

    Full Text Available Langevin transducers are employed in several applications, such as power ultrasound systems, naval hydrophones, and high-displacement actuators. Nonlinear effects can influence their performance, especially at high vibration amplitude levels. These nonlinear effects produce variations in the resonant frequency, harmonics of the excitation frequency, in addition to loss of symmetry in the frequency response and “frequency domain hysteresis”. In this context, this paper presents a simplified nonlinear dynamic model of power ultrasound transducers requiring only two parameters for simulating the most relevant nonlinear effects. One parameter reproduces the changes in the resonance frequency and the other introduces the dependence of the frequency response on the history of the system. The piezoelectric constitutive equations are extended by a linear dependence of the elastic constant on the mechanical displacement amplitude. For introducing the frequency hysteresis, the elastic constant is computed by combining the current value of the mechanical amplitude with the previous state amplitude. The model developed in this work is applied for predicting the dynamic responses of a 26 kHz ultrasonic transducer. The comparison of theoretical and experimental responses, obtained at several input voltages around the tuned frequency, shows a good agreement, indicating that the model can accurately describe the transducer nonlinear behavior.

  15. Analysis of a non-contact magnetoelastic torque transducer

    International Nuclear Information System (INIS)

    Andreescu, R.; Spellman, B.; Furlani, E.P.

    2008-01-01

    Results are presented for the performance of a magnetoelastic torque transducer that converts a torque-induced strain in a non-magnetic shaft into changes in a measurable magnetic field. The magnetic field is generated by a thin magnetostrictive layer that is coated onto the circumference of the shaft. The layer is magnetized and has an initial residual strain. The magnetization within the layer rotates in response to changes in the strain which occur when the shaft is torqued. The magnetic field produced by the layer changes with the magnetization and this can be sensed by a magnetometer to monitor the torque on the shaft. In this paper, a phenomenological theory is developed for predicting the performance of the transducer. The theory can be used to predict the magnetic field distribution of the transducer as a function of the physical properties of the magnetic coating, its residual strain, and the applied torque. It enables rapid parametric analysis of transducer performance, which is useful for the development and optimization of novel non-contact torque sensors

  16. Power doppler 'blanching' after the application of transducer pressure

    International Nuclear Information System (INIS)

    Joshua, F.; Edmonds, J.; Lassere, M.; De Carle, R.; Rayment, M.; Bryant, C.; Shnier, R.

    2005-01-01

    The aim of this study was to determine if transducer pressure modifies power Doppler assessments of rheumatoid arthritis synovium at the metacarpophalangeal joints and metatarsophalangeal joints. Five rheumatoid arthritis patients of varying degrees of 'disease activity' and damage were assessed with power Doppler ultrasound scanning of the dominant hand second to fifth metacarpophalangeal joints. Two rheumatoid arthritis patients had their dominant foot first to fifth metatarsophalangeal joints assessed with power Doppler ultrasound. Ultrasonography was performed with a high frequency transducer (14 MHz) with a colour mode frequency of 10 Mhz, and a standard colour box and gain. In the joint that showed the highest power Doppler signal, an image was made. A further image was taken after transducer pressure was applied. In all patients, there was increased flow to at least one joint. After pressure was applied, power Doppler signal intensity markedly reduced in all images and in some there was no recordable power Doppler signal. Increased transducer pressure can result in a marked reduction or obliteration in power Doppler signal. This power Doppler 'blanching' shows the need for further studies to evaluate sources of error and standardization before power Doppler ultrasound becomes a routine measure of 'disease activity' in rheumatoid arthritis. Copyright (2005) Blackwell Science Pty Ltd

  17. A capacitive ultrasonic transducer based on parametric resonance.

    Science.gov (United States)

    Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F

    2017-07-24

    A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of f o . When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2f o with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at f o frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

  18. Testing of electron beam welding by ultrasonic transducers

    International Nuclear Information System (INIS)

    Touffait, A.-M.; Roule, M.; Destribats, M.-T.

    1978-01-01

    Focalized ultrasonic testing is well adapted to the study of electron beam welding. This type of welding leads to narrow weld beads and to small dimension testing zones. Focalized transducers can be used enabling very small defects to be detected [fr

  19. Instantaneous input electrical power measurements of HITU transducer

    International Nuclear Information System (INIS)

    Karaboece, B; Guelmez, Y; Rajagapol, S; Shaw, A

    2011-01-01

    HITU (High Intensity Theraupetic Ultrasound) transducers are widely used in therapeutic ultrasound in medicine. The output ultrasonic power of HITU transducer can be measured in number of methods described in IEC 61161 standard [1]. New IEC standards specifically for measurement of HITU equipment are under development. The ultrasound power radiated from a transducer is dependent on applied input electrical voltage and current and consequently power. But, up to now, no standardised method has been developed and adopted for the input electrical power measurements. Hence, a workpackage was carried out for the establishment of such method in the frequency range of 1 to 3 MHz as a part of EURAMET EMRP Era-net plus 'External Beam Cancer Therapy' project. Several current shunts were developed and evaluated. Current measurements were also realized with Philips current probe and preamplifier at NPL and Agilent current probe at UME. In this paper, a method for the measurement of instantaneous electrical power delivered to a reactive ultrasound transducer in the required frequency range is explored.

  20. Candle soot nanoparticles-polydimethylsiloxane composites for laser ultrasound transducers

    Science.gov (United States)

    Chang, Wei-Yi; Huang, Wenbin; Kim, Jinwook; Li, Sibo; Jiang, Xiaoning

    2015-10-01

    Generation of high power laser ultrasound strongly demands the advanced materials with efficient laser energy absorption, fast thermal diffusion, and large thermoelastic expansion capabilities. In this study, candle soot nanoparticles-polydimethylsiloxane (CSNPs-PDMS) composite was investigated as the functional layer for an optoacoustic transducer with high-energy conversion efficiency. The mean diameter of the collected candle soot carbon nanoparticles is about 45 nm, and the light absorption ratio at 532 nm wavelength is up to 96.24%. The prototyped CSNPs-PDMS nano-composite laser ultrasound transducer was characterized and compared with transducers using Cr-PDMS, carbon black (CB)-PDMS, and carbon nano-fiber (CNFs)-PDMS composites, respectively. Energy conversion coefficient and -6 dB frequency bandwidth of the CSNPs-PDMS composite laser ultrasound transducer were measured to be 4.41 × 10-3 and 21 MHz, respectively. The unprecedented laser ultrasound transduction performance using CSNPs-PDMS nano-composites is promising for a broad range of ultrasound therapy applications.

  1. Enhancing endosomal escape of transduced proteins by photochemical internalisation.

    Directory of Open Access Journals (Sweden)

    Kevin Mellert

    Full Text Available Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

  2. Enhancing endosomal escape of transduced proteins by photochemical internalisation.

    Science.gov (United States)

    Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

    2012-01-01

    Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

  3. A capacitive ultrasonic transducer based on parametric resonance

    Science.gov (United States)

    Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F.

    2017-07-01

    A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

  4. Electrical capacity and resistance determination of emitting electric transducer

    International Nuclear Information System (INIS)

    Alba Fernandez, J.; Ramis Soriano, J.

    2000-01-01

    In this work we calculate the electrical resistance and capacity of emitting electric transducer, which is mainly formed, in direct relationship with its properties, by a ceramic capacitor. Our aim is to motivate the students with an attractive element in order to carry out traditional measurements of the charge and discharge transients of a capacitor, implementing high resistance setups. (Author) 5 refs

  5. Analysis of the conical piezoelectric acoustic emission transducer

    Czech Academy of Sciences Publication Activity Database

    Červená, Olga; Hora, Petr

    2008-01-01

    Roč. 2, č. 1 (2008), s. 13-24 ISSN 1802-680X R&D Projects: GA ČR GA101/06/1689 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission * conical transducer * FEM Subject RIV: BI - Acoustics

  6. Multilevel inverter based class D audio amplifier for capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

  7. Multilayer piezoelectric transducer models combined with Field II

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten; Jensen, Jørgen Arendt

    2012-01-01

    One-dimensional and three-dimensional axisymmetric transducer model have been compared to determine their feasibility to predict the volt-to-surface impulse response of a circular Pz27 piezoceramic disc. The ceramic is assumed mounted with silver electrodes, bounded at the outer circular boundary...

  8. Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery.

    Science.gov (United States)

    Wang, Zhenjun; Xu, Yuanming; Gu, Yuting

    2015-11-01

    Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Transducer frequency response variations investigated by time reversal calibration

    Czech Academy of Sciences Publication Activity Database

    Kober, Jan; Převorovský, Zdeněk

    2016-01-01

    Roč. 26, č. 2 (2016), A16-A16 ISSN 1213-3825. [Europen Conference on Acoustic Emission Testing /32./. 07.09.2016-09.09.2016, Praha] Institutional support: RVO:61388998 Keywords : calibration * time reversal * transducer * frequency response Subject RIV: BI - Acoustics

  10. Modelling of multilayer piezoelectric transducers for echographic applications Equivalent circuits

    International Nuclear Information System (INIS)

    Ramos, A.; Riera, E.; San Emeterio, J.L.; Sanz, P.T.

    1988-01-01

    In this paper, the main equivalent circuits of pulse-echo, single element, multilayer piezoelectric transducers, are analysed. The analogy of matching layers with lossless transmission lines is described. Finally, using the KLM model, the effects of backing and matching layers on the bandwidth and impulse response is analysed. (Author)

  11. A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    2015-08-01

    Full Text Available We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

  12. Effect of stimuli, transducers and gender on acoustic change complex

    Directory of Open Access Journals (Sweden)

    Hemanth N. Shetty

    2012-08-01

    Full Text Available The objective of this study was to investigate the effect of stimuli, transducers and gender on the latency and amplitude of acoustic change complex (ACC. ACC is a multiple overlapping P1-N1-P2 complex reflecting acoustic changes across the entire stimulus. Fifteen males and 15 females, in the age range of 18 to 25 (mean=21.67 years, having normal hearing participated in the study. The ACC was recorded using the vertical montage. The naturally produced stimuli /sa/ and /si/ were presented through the insert earphone/loud speaker to record the ACC. The ACC obtained from different stimuli presented through different transducers from male/female participants were analyzed using mixed analysis of variance. Dependent t-test and independent t-test were performed when indicated. There was a significant difference in latency of 2N1 at the transition, with latency for /sa/ being earlier; but not at the onset portions of ACC. There was no significant difference in amplitude of ACC between the stimuli. Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli. Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant. ACC provides important insight in detecting the subtle spectral changes in each stimulus. Among the transducers, no difference in ACC was noted as the spectra of stimuli delivered were within the frequency response of the transducers. The earlier 2N1 latency and larger N1 and 2P2 amplitudes noticed in female participants could be due to smaller head circumference. The findings of this study will be useful in determining the capacity of the auditory pathway in detecting subtle spectral changes in the stimulus at the level of the auditory cortex.

  13. Development of transducers for integrated garter spring repositioning system

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, B S.V.G.; Shyam, T V; Shrivastava, A K; Rupani, B B; Sinha, R K [Bhabha Atomic Research Centre, Bombay (India). Reactor Engineering Div.

    1994-12-31

    In order to reposition the dislocated garter springs in active channels of 235 MW Pressurised Heavy Water Reactors (PHWRs), a tool named as Integrated Garter Spring Repositioning System (INGRES) has been developed. The tool consists of transducers to detect the concentricity between the Pressure Tube (P/T) and Calandria Tube (C/T) and also to detect garter springs in the channel besides different modules for correcting the eccentricity between P/T and C/T and garter spring repositioning. The transducers used in the system namely Concentricity Detection Probe (CDP) and Garter Spring Detection Probe (GSDP) are based on the eddy current techniques. The CDP makes use of four eddy current bobbin probes separated 90 degrees apart in cross sectional plane of channel assembly. The transducer gives output signal in proportional to the air gap between P/T and C/T in two axes (X and Y) which are designed for the purpose. The output of the unit is obtained on the Cathode Ray Oscilloscope (CRO) screen in the form of illuminated dot. The dot position on the CRO screen gives the information about mismatch in concentricity between P/T and C/T of the channel. The GSDP meant for detecting garter springs in PHWR channel uses two sets of primary and secondary coils connected in differential mode. The output signals from the transducers are processed through a signal processing unit devised for the purpose to obtain output from it as a horizontal beam on the CRO screen. The garter spring presence in the channel is indicated by a change in the voltage level of beam and also by audio-visual indication in the form of buzzer and LED illumination on the processing unit. This paper gives general design and development aspects of the CDP and GSDP transducers of the INGRES tool. (author). 3 figs.

  14. Nuclear Radiation Tolerance of Single Crystal Aluminum Nitride Ultrasonic Transducer

    Science.gov (United States)

    Reinhard, Brian; Tittmann, Bernhard R.; Suprock, Andrew

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models, (Rempe et al., 2011; Kazys et al., 2005). These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The irradiation is also supported by a multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET ASI) program. The results from this irradiation, which started in February 2014, offer the potential to enable the development of novel radiation tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. Hence, results from this irradiation offer the potential to bridge the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the

  15. Six-Axis Force-Torque Transducer for Mars 2018 Mission, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A transducer element that is hearty enough for a Mars lander mission needs to be developed so that a six-axis force and torque transducer is possible. The technical...

  16. Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Grzegorz Psuj

    2012-01-01

    Full Text Available The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS. Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

  17. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Brian; Tittmann, Bernhard [The Pennsylvania State University (United States); Rempe, Joy; Daw, Joshua [Idaho National Laboratory (United States); Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov [Massachusetts Institute of Technology (United States); Ramuhalli, Pradeep; Montgomery, Robert [Pacific Northwest National Laboratory (United States); Chien, Hualte [Argonne National Laboratory (United States); Wernsman, Bernard [Bechtel Marine Propulsion Corp (United States)

    2015-03-31

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  18. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Science.gov (United States)

    Reinhardt, Brian; Tittmann, Bernhard; Rempe, Joy; Daw, Joshua; Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov; Ramuhalli, Pradeep; Montgomery, Robert; Chien, Hualte; Wernsman, Bernard

    2015-03-01

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  19. A laboratory device for evaluation and study in the filed of ultrasonic transducers

    International Nuclear Information System (INIS)

    Vasiliu, S.

    1978-12-01

    A laboratory device for evaluation of the ultrasonic transducers, in view of adequate selection according to the testing requirements is presented. Recordings of ultrasonic beam of some transducers delivered as being of the same type are presented, showing important departures from specifications of the characteristics. Some of transducers evaluated have not been found acceptable for NDT in the nuclear field. (author)

  20. Measurement of vehicle-load using capacitance and acceleration transducers

    International Nuclear Information System (INIS)

    Yang, S; Yang, W; Yang, Y

    2007-01-01

    Over-loading is a common problem in some developing countries. Currently, large and fixed measurement systems are used to measure the load of vehicles travelling on highways. This paper presents an on-vehicle measuring device, which is based on measurement of change in capacitance due to variation in distance between electrodes mounted on vehicles. The on-vehicle leaf springs are used as a key part of the weighing transducer. Acceleration transducers are used to measure the vehicle's forward and the vertical accelerations. A feature of this on-vehicle measuring device is that it can provide both static and dynamic load measurements. The drivers can check the load in the cab, and the highway inspectors can check the load at any time and any place through radio communication, thus identifying over-loaded vehicles

  1. W-Band Circularly Polarized TE11 Mode Transducer

    Science.gov (United States)

    Zhan, Mingzhou; He, Wangdong; Wang, Lei

    2018-06-01

    This paper presents a balanced sidewall exciting approach to realize the circularly polarized TE11 mode transducer. We used a voltage vector transfer matrix to establish the relationship between input and output vectors, then we analyzed amplitude and phase errors to estimate the isolation of degenerate mode. A mode transducer with a sidewall exciter was designed based on the results. In the 88-100 GHz frequency range, the simulated axial ratio is less than 1.05 and the isolation of linearly polarization TE11 mode is higher than 30 dBc. In back-to-back measurements, the return loss is generally greater than 20 dB with a typical insertion loss of 1.2 dB. Back-to-back transmission measurements are in excellent agreement with simulations.

  2. The copying power of one-state tree transducers

    DEFF Research Database (Denmark)

    Engelfriet, Joost; Skyum, Sven

    1982-01-01

    One-state deterministic top-down tree transducers (or, tree homomorphisms) cannot handle “prime copying,” i.e., their class of output (string) languages is not closed under the operation L → {$(w$)f(n) short parallel w ε L, f(n) greater-or-equal, slanted 1}, where f is any integer function whose...... range contains numbers with arbitrarily large prime factors (such as a polynomial). The exact amount of nonclosure under these copying operations is established for several classes of input (tree) languages. These results are relevant to the extended definable (or, restricted parallel level) languages......, to the syntax-directed translation of context-free languages, and to the tree transducer hierarchy....

  3. Transducers for providing an electrical signal representative of physical movement

    International Nuclear Information System (INIS)

    Duncombe, E.; Roach, P.F.

    1985-01-01

    A transducer for use in hostile environments has an externally threaded rod slidable in an internally threaded tube. The threads of rod and tube are of two-start form and define slots in which inductively coupled mineral insulated conductors are located, the conductors being of hairpin form secured at the ends of the rod and tube at the hairpin bend with the hairpin tails in the slots. End diaphragms make a sealed transducer in which the rod can move axially relative to the tube by one half of one pitch of the threads without straining the diaphragms. In a modification rod and tube are arranged to rotate relative to each other up to +-180 0 which effectively also causes a one half pitch movement of the conductors. (author)

  4. Capacitive micromachined ultrasonic transducers for medical imaging and therapy

    International Nuclear Information System (INIS)

    Khuri-Yakub, Butrus T; Oralkan, Ömer

    2011-01-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated front-end electronic circuits we developed and their use for 2D and 3D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a micro-electro-mechanical systems technology for many medical diagnostic and therapeutic applications

  5. Capacitive micromachined ultrasonic transducers for medical imaging and therapy.

    Science.gov (United States)

    Khuri-Yakub, Butrus T; Oralkan, Omer

    2011-05-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications.

  6. Electromechanical modelling of tapered ionic polymer metal composites transducers

    Directory of Open Access Journals (Sweden)

    Rakesha Chandra Dash

    2016-09-01

    Full Text Available Ionic polymer metal composites (IPMCs are relatively new smart materials that exhibit a bidirectional electromechanical coupling. IPMCs have large number of important engineering applications such as micro robotics, biomedical devices, biomimetic robotics etc. This paper presents a comparison between tapered and uniform cantilevered Nafion based IPMCs transducer. Electromechanical modelling is done for the tapered beam. Thickness can be varied according to the requirement of force and deflection. Numerical results pertaining to the force and deflection characteristics of both type IPMCs transducer are obtained. It is shown that the desired amount of force and deflections for tapered IPMCs can be achieved for a given voltage. Different fixed end (t0 and free end (t1 thickness values have been taken to justify the results using MATLAB.

  7. Nonlinear electromechanical response of the ferroelectret ultrasonic transducers

    Czech Academy of Sciences Publication Activity Database

    Döring, J.; Bovtun, Viktor; Bartusch, J.; Erhard, A.; Kreutzbruck, M.; Yakymenko, Y.

    2010-01-01

    Roč. 100, č. 2 (2010), 479-485 ISSN 0947-8396 R&D Projects: GA ČR GAP204/10/0616; GA ČR(CZ) GA202/09/0682 Institutional research plan: CEZ:AV0Z10100520 Keywords : piezoelectric * ferroelectret * transducer * ultrasonic Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.765, year: 2010

  8. Application of digital PWM technology in current transducers

    International Nuclear Information System (INIS)

    Liu Huifang; Hu Zhimin; Li Rui

    2012-01-01

    With the development of DSP technology and mature use of PID technology,, a new program for DC or AC signal measurement is proposed. Combined with the DSP chip timer module and PID algorithm, PWM signals are generated to control the feedback circuit for the compensation current. Finally the measured current value can be obtained according to the ampere-turns compensation current and the measured current. Studies have shown that this technology enables new current transducers have high stability. (authors)

  9. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Science.gov (United States)

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. An all-optical fiber optic photoacoustic transducer

    Science.gov (United States)

    Thathachary, Supriya V.; Motameni, Cameron; Ashkenazi, Shai

    2018-02-01

    A highly sensitive fiber-optic Fabry-Perot photoacoustic transducer is proposed in this work. The transducer will consist of separate transmit and receive fibers. The receiver will be composed of a Fabry-Perot Ultrasound sensor with a selfwritten waveguide with all-optical ultrasound detection with high sensitivity. In previous work, we have shown an increase in resonator Q-factor from 1900 to 3200 for a simulated Fabry-Perot ultrasound detector of 45 μm thickness upon including a waveguide to limit lateral power losses. Subsequently, we demonstrated a prototype device with 30nm gold mirrors and a cavity composed of the photosensitive polymer Benzocyclobutene. This 80 µm thick device showed an improvement in its Q-factor from 2500 to 5200 after a selfaligned waveguide was written into the cavity using UV exposure. Current work uses a significantly faster fabrication technique using a combination of UV-cured epoxies for the cavity medium, and the waveguide within it. This reduces the fabrication time from several hours to a few minutes, and significantly lowers the cost of fabrication. We use a dip-coating technique to deposit the polymer layer. Future work will include the use of Dielectric Bragg mirrors in place of gold to achieve better reflectivity, thereby further improving the Q-factor of the device. The complete transducer presents an ideal solution for intravascular imaging in cases where tissue differentiation is desirable, an important feature in interventional procedures where arterial perforation is a risk. The final design proposed comprises the transducer within a guidewire to guide interventions for Chronic Total Occlusions, a disease state for which there are currently no invasive imaging options.

  11. Finite element analysis of hysteresis effects in piezoelectric transducers

    Science.gov (United States)

    Simkovics, Reinhard; Landes, Hermann; Kaltenbacher, Manfred; Hoffelner, Johann; Lerch, Reinhard

    2000-06-01

    The design of ultrasonic transducers for high power applications, e.g. in medical therapy or production engineering, asks for effective computer aided design tools to analyze the occurring nonlinear effects. In this paper the finite-element-boundary-element package CAPA is presented that allows to model different types of electromechanical sensors and actuators. These transducers are based on various physical coupling effects, such as piezoelectricity or magneto- mechanical interactions. Their computer modeling requires the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields as well as coupled mechanical-acoustic fields. With the reported software environment we are able to compute the dynamic behavior of electromechanical sensors and actuators by taking into account geometric nonlinearities, nonlinear wave propagation and ferroelectric as well as magnetic material nonlinearities. After a short introduction to the basic theory of the numerical calculation schemes, two practical examples will demonstrate the applicability of the numerical simulation tool. As a first example an ultrasonic thickness mode transducer consisting of a piezoceramic material used for high power ultrasound production is examined. Due to ferroelectric hysteresis, higher order harmonics can be detected in the actuators input current. Also in case of electrical and mechanical prestressing a resonance frequency shift occurs, caused by ferroelectric hysteresis and nonlinear dependencies of the material coefficients on electric field and mechanical stresses. As a second example, a power ultrasound transducer used in HIFU-therapy (high intensity focused ultrasound) is presented. Due to the compressibility and losses in the propagating fluid a nonlinear shock wave generation can be observed. For both examples a good agreement between numerical simulation and experimental data has been achieved.

  12. Sensitivity limits of capacitive transducer for gravitational wave resonant antennas

    Energy Technology Data Exchange (ETDEWEB)

    Bassan, M; Pizzella, G [Rome Tor Vergata Univ. (Italy). Dip. di Fisica

    1996-12-01

    It is analyzed the performance of a resonant gravitational wave antenna equipped with a resonant, d.c. biased capacitive transducer, an untuned superconducting matching circuit and a d.c. Squid. It is derived simple relations for the detector energy sensitivity that serve as guidelines for device development and it is shown that, with reasonable improvements in Squid technology, an effective temperature for burst detection of 2miK can be achieved.

  13. Review of piezoelectric micromachined ultrasonic transducers and their applications

    International Nuclear Information System (INIS)

    Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Shin, Eunjung; Choi, Hongsoo; Ryu, Jungho

    2017-01-01

    In recent decades, micromachined ultrasonic transducers (MUTs) have been investigated as an alternative to conventional piezocomposite ultrasonic transducers, primarily due to the advantages that microelectromechanical systems provide. Miniaturized ultrasonic systems require ultrasonic transducers integrated with complementary metal-oxide-semiconductor circuits. Hence, piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs) have been developed as the most favorable solutions. This paper reviews the basic equations to understand the characteristics of thin-film-based piezoelectric devices and presents recent research on pMUTs, including current approaches and limitations. Methods to improve the coupling coefficient of pMUTs are also investigated, such as device structure, materials, and fabrication techniques. The device structure improvements include multielectrode pMUTs, partially clamped boundary conditions, and 3D pMUTs (curved and domed types), where the latter can provide an electromechanical coupling coefficient of up to 45%. The piezoelectric coefficient ( e 31 ) can be increased by controlling the crystal texture (seed layer of γ -Al 2 O 3 ), using single-crystal (PMN-PT) materials, or control of residual stresses (using SiO 2 layer). Arrays of pMUTs can be implemented for various applications including intravascular ultrasound, fingerprint sensors, rangefinders in air, and wireless power supply systems. pMUTs are expected to be an ideal solution for applications such as mobile biometric security (fingerprint sensors) and rangefinders due to their superior power efficiency and compact size. (topical review)

  14. Development of ultrasonic testing equipment incorporating electromagnetic acoustic transducer

    International Nuclear Information System (INIS)

    Sato, Michio; Kimura, Motohiko; Okano, Hideharu; Miyazawa, Tatsuo; Nagase, Koichi; Ishikawa, Masaaki

    1989-01-01

    An ultrasonic testing equipment for use in in-service inspection of nuclear power plant piping has been developed, which comprises an angle-beam electromagnetic acoustic transducer mounted on a vehicle for scanning the piping surface to be inspected. The transducer functions without direct contact with the piping surface through couplant, and the vehicle does not require a guide track installed on the piping surface, being equipped with magnetic wheels that adhere to the piping material, permitting it to travel along the circumferential weld joint of a carbon steel pipe. The equipment thus dispenses with the laborious manual work involved in preparing the piping for inspection, such as removal of protective coating, surface polishing and installation of guide track and thereby considerably reduces the duration of inspection. The functioning principle and structural features of the transducer and vehicle are described, together with the results of trial operation of a prototype unit, which proved a 1mm deep notch cut on a test piece of 25mm thick carbon steel plate to be locatable with an accuracy of ±2mm. (author)

  15. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

    Directory of Open Access Journals (Sweden)

    Samuel Pichardo

    Full Text Available Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13:135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode. The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d. resonance frequency of the samples was 465.1 (± 1.5 kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

  16. Tungsten Oxide Photonic Crystals as Optical Transducer for Gas Sensing.

    Science.gov (United States)

    Amrehn, Sabrina; Wu, Xia; Wagner, Thorsten

    2018-01-26

    Some metal oxide semiconductors, such as tungsten trioxide or tin dioxide, are well-known as resistive transducers for gas sensing and offer high sensitivities down to the part per billion level. Electrical signal read-out, however, limits the information obtained on the electronic properties of metal oxides to a certain frequency range and its application because of the required electrical contacts. Therefore, a novel approach for building an optical transducer for gas reactions utilizing metal oxide photonic crystals is presented here. By the rational design of the structure and composition it is possible to synthesize a functional material which allows one to obtain insight into its electronic properties in the optical frequency range with simple experimental measures. The concept is demonstrated by tungsten trioxide inverse opal structure as optical transducer material for hydrogen sensing. The sensing behavior is analyzed in a temperature range from room temperature to 500 °C and in a wide hydrogen concentration range (3000 ppm to 10%). The sensing mechanism is mainly the refractive index change resulting from hydrogen intercalation in tungsten trioxide, but the back reaction has also impact on the optical properties of this system. Detailed chemical reaction studies provide suggestions for specific sensing conditions.

  17. Ergonomic design and evaluation of a diagnostic ultrasound transducer holder.

    Science.gov (United States)

    Ghasemi, Mohamad Sadegh; Hosseinzadeh, Payam; Zamani, Farhad; Ahmadpoor, Hossein; Dehghan, Naser

    2017-12-01

    Work-related musculoskeletal disorders (WMSDs) are injuries and disorders that affect the body's movement and musculoskeletal system. Awkward postures represent one of the major ergonomic risk factors that cause WMSDs among sonographers while working with an ultrasound transducer. This study aimed to design and evaluate a new holder for the ultrasound transducer. In the first phase a new holder was designed for the transducer, considering design principles. Evaluation of the new holder was then carried out by electrogoniometry and a locally perceived discomfort (LPD) scale. The application of design principles to the new holder resulted in an improvement of wrist posture and comfort. Wrist angles in extension, flexion, radial deviation and ulnar deviation were lower with utilization of the new holder. The severity of discomfort based on the LPD method in the two modes of work with and without the new holder was reported with values of 1.3 and 1.8, respectively (p ergonomics design principles was effective in minimizing wrist deviation and increasing comfort while working with the new holder.

  18. Damage detection with concentrated configurations of piezoelectric transducers

    International Nuclear Information System (INIS)

    Wandowski, T; Malinowski, P; Ostachowicz, W M

    2011-01-01

    In this paper results of investigation on concentrated piezoelectric networks with different configurations are presented. They were used for elastic wave generation and acquisition. The elastic wave propagation phenomenon was used for damage localization in thin aluminium panels. This approach utilized the fact that any discontinuities existing in structural elements cause local changes of physical material properties which affect elastic wave propagation. Elastic waves were excited and received using piezoelectric transducer networks with different element arrangements. The method of transducer placement and the number of piezoelectric elements used had an influence on the accuracy of the damage localization algorithm. Obviously, the more elements there were, the more data had to be processed. After the acquisition process signal processing was conducted in order to create damage influence maps. These maps presents elastic wave energy connected with reflection from discontinuities. In order to create such a map a computer program was developed that assigns a mesh of points to the panel surface. At each point the energy of elastic wave reflection was calculated. This energy was extracted from the acquired signals. This paper summarizes an extensive experimental investigation that included three damage scenarios and twelve transducer configurations

  19. Review of piezoelectric micromachined ultrasonic transducers and their applications

    Science.gov (United States)

    Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Shin, Eunjung; Ryu, Jungho; Choi, Hongsoo

    2017-11-01

    In recent decades, micromachined ultrasonic transducers (MUTs) have been investigated as an alternative to conventional piezocomposite ultrasonic transducers, primarily due to the advantages that microelectromechanical systems provide. Miniaturized ultrasonic systems require ultrasonic transducers integrated with complementary metal-oxide-semiconductor circuits. Hence, piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs) have been developed as the most favorable solutions. This paper reviews the basic equations to understand the characteristics of thin-film-based piezoelectric devices and presents recent research on pMUTs, including current approaches and limitations. Methods to improve the coupling coefficient of pMUTs are also investigated, such as device structure, materials, and fabrication techniques. The device structure improvements include multielectrode pMUTs, partially clamped boundary conditions, and 3D pMUTs (curved and domed types), where the latter can provide an electromechanical coupling coefficient of up to 45%. The piezoelectric coefficient (e 31) can be increased by controlling the crystal texture (seed layer of γ-Al2O3), using single-crystal (PMN-PT) materials, or control of residual stresses (using SiO2 layer). Arrays of pMUTs can be implemented for various applications including intravascular ultrasound, fingerprint sensors, rangefinders in air, and wireless power supply systems. pMUTs are expected to be an ideal solution for applications such as mobile biometric security (fingerprint sensors) and rangefinders due to their superior power efficiency and compact size.

  20. Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... transducer model and the FIELD II software in combination give good agreement with measurements....

  1. Research and development of in-core transducers at the CIAE

    International Nuclear Information System (INIS)

    Huang Yucai; Liu Yupu; Jia Guozhen; Liu Lianping

    1996-01-01

    In this paper, R and D of in-core transducers at the CIAE are briefly summarized. With the construction and commissioning of PWR nuclear power plant in China, fuel rod behaviour need to be studied carefully. As conventional transducers cannot meet the requirements of in-core applications, R and D of in-core transducers are developed. Since 1980's, several kinds of in-core transducers have been successfully fabricated and tested under the conditions simulating PWR. At present, in-pile tests of the transducers combining with the studies of individual behaviour of PWR fuel rod are being planned at the CIAE. (author). 11 refs, 12 figs, 4 tabs

  2. Positioning calibration apparatus for transducers employed in nuclear reactor vessel inspection apparatus

    International Nuclear Information System (INIS)

    Elsner, H.J.

    1981-01-01

    The invention provides a calibration apparatus suitable for verifying the position and orientation of transducers used in reactor vessel ultrasonic inspection. The apparatus includes moveable mounting means which secures a transducer within the tank in its normal inspection orientation. A drive is also provided for moving the transducer in the tank relative to a target. The target is slidably positioned in the tank at a distance from the transducer which is selected to avoid the distortion effects in the near field of the transducer. The drive mechanism may be provided with graduated indicia of travel, or a scale may be affixed to the side of the tank. (L.L.)

  3. Full-scale Mark II CRT program: dynamic response evaluation test of pressure transducers

    International Nuclear Information System (INIS)

    Kukita, Yutaka; Namatame, Ken; Takeshita, Isao; Shiba, Masayoshi

    1982-12-01

    A dynamic response evaluation test of pressure transducers was conducted in support of the JAERI Full-Scale Mark II CRT (Containment Response Test) Program. The test results indicated that certain of the cavity-type transducers used in the early blowdown test had undesirable response characteristics. The transducer mounting scheme was modified to avoid trapping of air bubbles in the pressure transmission tubing attached to the transducers. The dynamic response of the modified transducers was acceptable within the frequency range of 200 Hz. (author)

  4. A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet.

    Science.gov (United States)

    Liu, Yingxiang; Liu, Junkao; Chen, Weishan; Shi, Shengjun

    2012-05-01

    A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms).

  5. IRE1: ER stress sensor and cell fate executor.

    Science.gov (United States)

    Chen, Yani; Brandizzi, Federica

    2013-11-01

    Cells operate a signaling network termed the unfolded protein response (UPR) to monitor protein-folding capacity in the endoplasmic reticulum (ER). Inositol-requiring enzyme 1 (IRE1) is an ER transmembrane sensor that activates the UPR to maintain the ER and cellular function. Although mammalian IRE1 promotes cell survival, it can initiate apoptosis via decay of antiapoptotic miRNAs. Convergent and divergent IRE1 characteristics between plants and animals underscore its significance in cellular homeostasis. This review provides an updated scenario of the IRE1 signaling model, discusses emerging IRE1 sensing mechanisms, compares IRE1 features among species, and outlines exciting future directions in UPR research. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Cotranslocational degradation: utilitarianism in the ER stress response.

    Science.gov (United States)

    Pearse, Bradley R; Hebert, Daniel N

    2006-09-15

    Recently, a new layer of the unfolded protein response was discovered that supports the cotranslocational degradation of nascent chains stalled in endoplasmic reticulum translocons (Oyadomari et al., 2006).

  7. Energy harvesting for wireless sensors by using piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Duerager, Christian [Empa, Swiss Federal Laboratories for Materials Science and Technology, Duebendorf (Switzerland)

    2012-07-01

    Wireless sensor technology, which integrates transducers, measurement electronics and wireless communication, has become increasingly vital in structural health monitoring (SHM) applications. Compared to traditional wired systems, wireless solutions reduce the installation time and costs and are not subjected to breakage caused by harsh weather conditions or other extreme events. Because of the low installation costs, wireless sensor networks allow the deployment of a big number of wireless sensor nodes on the structures. Moreover, the nodes can be placed on particularly critical components of the structure difficult to reach by wires. In most of the cases the power supply are conventional batteries, which could be a problem because of their finite life span. Furthermore, in the case of wireless sensor nodes located on structures, it is often advantageous to embed them, which makes an access impossible. Therefore, if a method of obtaining the untapped energy surrounding these sensors was implemented, significant life could be added to the power supply. Various approaches to energy harvesting and energy storage are discussed and limitations associated with the current technology are addressed. In this paper we first discuss the research that has been performed in the area of energy harvesting for wireless sensor technologies by using the ambient vibration energy. In many cases the energy produced by the ambient vibrations is far too small to directly power a wireless sensor node. Therefore, in a second step we discuss the development process for an electronic energy harvesting circuit optimized for piezoelectric transducers. In the last part of this paper an experiment with different piezoelectric transducers and their applicability for energy harvesting applications on vibrating structures will be discussed. (orig.)

  8. Development of a novel omnidirectional magnetostrictive transducer for plate applications

    Science.gov (United States)

    Vinogradov, Sergey; Cobb, Adam; Bartlett, Jonathan; Udagawa, Youichi

    2018-04-01

    The application of guided waves for the testing of plate-type structures has been recently investigated by a number of research groups due to the ability of guided waves to detect corrosion in remote and hidden areas. Guided wave sensors for plate applications can be either directed (i.e., the waves propagate in a single direction) or omnidirectional. Each type has certain advantages and disadvantages. Omnidirectional sensors can inspect large areas from a single location, but it is challenging to define where a feature is located. Conversely, directed sensors can be used to precisely locate an indication, but have no sensitivity to flaws away from the wave propagation direction. This work describes a newly developed sensor that combines the strengths of both sensor types to create a novel omnidirectional transducer. The sensor transduction is based on a custom magnetostrictive transducer (MsT). In this new probe design, a directed, plate-application MsT with known characteristics was incorporated into an automated scanner. This scanner rotates the directed MsT for data collection at regular intervals. Coupling of the transducer to the plate is accomplished using a shear wave couplant. The array of data that is received is used for compiling B-scans and imaging, utilizing a synthetic aperture focusing algorithm (SAFT). The performance of the probe was evaluated on a 0.5-inch thick carbon steel plate mockup with a surface area of over 100 square feet. The mockup had a variety of known anomalies representing localized and distributed pitting corrosion, gradual wall thinning, and notches of different depths. Experimental data was also acquired using the new probe on a retired storage tank with known corrosion damage. The performance of the new sensor and its limitations are discussed together with general directions in technology development.

  9. Design and analysis of fractional order seismic transducer for displacement and acceleration measurements

    Science.gov (United States)

    Veeraian, Parthasarathi; Gandhi, Uma; Mangalanathan, Umapathy

    2018-04-01

    Seismic transducers are widely used for measurement of displacement, velocity, and acceleration. This paper presents the design of seismic transducer in the fractional domain for the measurement of displacement and acceleration. The fractional order transfer function for seismic displacement and acceleration transducer are derived using Grünwald-Letnikov derivative. Frequency response analysis of fractional order seismic displacement transducer (FOSDT) and fractional order seismic acceleration transducer (FOSAT) are carried out for different damping ratio with the different fractional order, and the maximum dynamic measurement range is identified. The results demonstrate that fractional order seismic transducer has increased dynamic measurement range and less phase distortion as compared to the conventional seismic transducer even with a lower damping ratio. Time response of FOSDT and FOSAT are derived analytically in terms of Mittag-Leffler function, the effect of fractional behavior in the time domain is evaluated from the impulse and step response. The fractional order system is found to have significantly reduced overshoot as compared to the conventional transducer. The fractional order seismic transducer design proposed in this paper is illustrated with a design example for FOSDT and FOSAT. Finally, an electrical equivalent of FOSDT and FOSAT is considered, and its frequency response is found to be in close agreement with the proposed fractional order seismic transducer.

  10. LOFT liquid level transducer application techniques and measurement uncertainty

    International Nuclear Information System (INIS)

    Batt, D.L.; Biladeau, G.L.; Goodrich, L.D.; Nightingale, C.M.

    1979-01-01

    A conductivity sensitive liquid level transducer (LLT) has been designed and used successfully for determining whether steam or water is present in the Loss-of-Fluid Tests (LOFT) performed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory. The presence of steam or water is determined by establishing a discriminator level which is set manually. A computer program establishes the presence or absence of water for each data point taken. In addition to liquid level, the LLT is used for reactor vessel mass and volume calculations. The uncertainty in the liquid level is essentially the spacing of the LLT electrodes

  11. Capacitive micromachined ultrasonic transducer arrays as tunable acoustic metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Lani, Shane W., E-mail: shane.w.lani@gmail.com, E-mail: karim.sabra@me.gatech.edu, E-mail: levent.degertekin@me.gatech.edu; Sabra, Karim G. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); Wasequr Rashid, M.; Hasler, Jennifer [School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States); Levent Degertekin, F. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States)

    2014-02-03

    Capacitive Micromachined Ultrasonic Transducers (CMUTs) operating in immersion support dispersive evanescent waves due to the subwavelength periodic structure of electrostatically actuated membranes in the array. Evanescent wave characteristics also depend on the membrane resonance which is modified by the externally applied bias voltage, offering a mechanism to tune the CMUT array as an acoustic metamaterial. The dispersion and tunability characteristics are examined using a computationally efficient, mutual radiation impedance based approach to model a finite-size array and realistic parameters of variation. The simulations are verified, and tunability is demonstrated by experiments on a linear CMUT array operating in 2-12 MHz range.

  12. The Current State of Silicone-Based Dielectric Elastomer Transducers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

    2016-01-01

    class of transducer due to their inherent lightweight and potentially large strains. For the field to progress towards industrial implementation, a leap in material devel- opment is required, specifically targeting longer lifetime and higher energy densities to provide more efficient transduction at lower...... driving voltages. In this review, the current state of sili- cone elastomers for DETs is summarised and critically discussed, including commercial elastomers, composites, polymer blends, grafted elastomers and complex network structures. For future developments in the field it is essential that all aspects...

  13. Production of particulates from transducer erosion: implications on food safety.

    Science.gov (United States)

    Mawson, Raymond; Rout, Manoj; Ripoll, Gabriela; Swiergon, Piotr; Singh, Tanoj; Knoerzer, Kai; Juliano, Pablo

    2014-11-01

    The formation of metallic particulates from erosion was investigated by running a series of transducers at various frequencies in water. Two low frequency transducer sonotrodes were run for 7.5h at 18kHz and 20kHz. Three high frequency plates operating at megasonic frequencies of 0.4MHz, 1MHz, and 2MHz were run over a 7days period. Electrical conductivity and pH of the solution were measured before and after each run. A portion of the non-sonicated and treated water was partially evaporated to achieve an 80-fold concentration of particles and then sieved through nano-filters of 0.1μm, 0.05μm, and 0.01μm. An aliquot of the evaporated liquid was also completely dried on strips of carbon tape to determine the presence of finer particles post sieving. An aliquot was analyzed for detection of 11 trace elements by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). The filters and carbon tapes were analyzed by FE-SEM imaging to track the presence of metals by EDS (Energy Dispersive Spectroscopy) and measure the particle size and approximate composition of individual particles detected. Light microscopy visualization was used to calculate the area occupied by the particles present in each filter and high resolution photography was used for visualization of sonotrode surfaces. The roughness of all transducers before and after sonication was tested through profilometry. No evidence of formation of nano-particles was found at any tested frequency. High amounts of metallic micron-sized particles at 18kHz and 20kHz formed within a day, while after 7day runs only a few metallic micro particles were detected above 0.4MHz. Erosion was corroborated by an increase in roughness in the 20kHz tip after ultrasound. The elemental analysis showed that metal leach occurred but values remained below accepted drinking water limits, even after excessively long exposure to ultrasound. With the proviso that the particles measured here were only characterized in two dimensions and could be

  14. Supported silver clusters as nanoplasmonic transducers for protein sensing

    DEFF Research Database (Denmark)

    Fojan, Peter; Hanif, Muhammad; Bartling, Stephen

    2015-01-01

    Transducers for optical sensing of proteins are prepared using cluster beam deposition on quartz substrates. Surface plasmon resonance phenomenon of the supported silver clusters is used for the detection. It is shown that surface immobilisation procedure providing adhesion of the silver clusters...... stages and protein immobilisation scheme the sensing of protein of interest can be assured using a relatively simple optical spectroscopy method....... an enhancement of the plasmon absorption band used for the detection. Atomic force microscopy study allows to suggest that immobilisation of antibodies on silver clusters has been achieved, thus giving a possibility to incubate and detect an antigen of interest. Hence, by applying the developed preparation...

  15. A Treatise on Acoustic Radiation. Volume 2. Acoustic Transducers

    Science.gov (United States)

    1983-01-01

    Newton) V (meter/sec) acoustical p (Newton/meter2 ) U (meter 3/sec) To display Eq. 1.53.1 in simple form we take time to be given by exp(- iot ) and choose...if all the C-component edges and e-drivers are in the tree, all the L-component "A edges and idrivers are in the cotree, all the algebraic equations...momentum and mass of the elastic field then become, (a) Al - V -T + F 278 W-4. ,-,- * * * 4 % • *.• Design of Acoustic Transducers IOT (b) I + VV-s

  16. Immersed acoustical transducers and their potential uses in LMFBR

    International Nuclear Information System (INIS)

    Argous, J.P.; Brunet, M.; Baron, J.; Lhuillier, C.; Segui, J.L.

    1980-04-01

    Six years satisfactory operation in PHENIX has proved the reliability and effectivness of under-sodium viewing (VISUS) and Acoustic Detection. This fact has been strong incentive to maintain, on the future LMFBR the visus as well as the Acoustic Detection functions. These two functions are performed on SUPER PHENIX, by two sets of distinct systems using the well-known solution. Taking into account of recent improvements in sodium immersible acoustic transducers technology, CEA decided to undertake the development of a multi-functions instrument. This paper gives an outline of this new concept, which should be able to reduce the cost and the complexity of core instrumentation

  17. Making transducers and sensors which lead to safer mining

    Energy Technology Data Exchange (ETDEWEB)

    Laird, R

    1977-10-20

    MRDE work on transducers and sensors is described. A device containing a radioactive source has already been developed for detecting the edge of a coal seam; on a device which senses the edge of the seam by measuring natural radiation form the neighbouring rocks. Hard bands or dirt in a seam can be located by measuring pick force or pick vibrations. Environmental monitors, sensors for measuring pressure and flow in methane drainage pipes, vibration monitors for fans, means of detecting cage position in pit shaft, and bunker control systems are also mentioned.

  18. Three-dimensional micro electromechanical system piezoelectric ultrasound transducer

    Science.gov (United States)

    Hajati, Arman; Latev, Dimitre; Gardner, Deane; Hajati, Azadeh; Imai, Darren; Torrey, Marc; Schoeppler, Martin

    2012-12-01

    Here we present the design and experimental acoustic test data for an ultrasound transducer technology based on a combination of micromachined dome-shaped piezoelectric resonators arranged in a flexible architecture. Our high performance niobium-doped lead zirconate titanate film is implemented in three-dimensional dome-shaped structures, which form the basic resonating cells. Adjustable frequency response is realized by mixing these basic cells and modifying their dimensions by lithography. Improved characteristics such as high sensitivity, adjustable wide-bandwidth frequency response, low transmit voltage compatible with ordinary integrated circuitry, low electrical impedance well matched to coaxial cabling, and intrinsic acoustic impedance match to water are demonstrated.

  19. Development of a Novel Transparent Flexible Capacitive Micromachined Ultrasonic Transducer

    Directory of Open Access Journals (Sweden)

    Da-Chen Pang

    2017-06-01

    Full Text Available This paper presents the world’s first transparent flexible capacitive micromachined ultrasonic transducer (CMUT that was fabricated through a roll-lamination technique. This polymer-based CMUT has advantages of transparency, flexibility, and non-contacting detection which provide unique functions in display panel applications. Comprising an indium tin oxide-polyethylene terephthalate (ITO-PET substrate, SU-8 sidewall and vibrating membranes, and silver nanowire transparent electrode, the transducer has visible-light transmittance exceeding 80% and can operate on curved surfaces with a 40 mm radius of curvature. Unlike the traditional silicon-based high temperature process, the CMUT can be fabricated on a flexible substrate at a temperature below 100 °C to reduce residual stress introduced at high temperature. The CMUT on the curved surfaces can detect a flat target and finger at distances up to 50 mm and 40 mm, respectively. The transparent flexible CMUT provides a better human-machine interface than existing touch panels because it can be integrated with a display panel for non-contacting control in a health conscious environment and the flexible feature is critical for curved display and wearable electronics.

  20. Putting Encyclopaedia Knowledge into Structural Form: Finite State Transducers Approach

    Directory of Open Access Journals (Sweden)

    Pajić Vesna

    2011-06-01

    Full Text Available In biology and functional genomics in particular, understanding the dependence and interplay between different genome and ecological characteristics of organisms is a very challenging problem. There are some public databases which combine this kind of information, but there is still much more information about microbes and other organisms that reside in unstructured and semi-structured documents, such as encyclopaedias. In this paper we present a method for extracting information from semi-structured resources, such as encyclopaedias, based on finite state transducers, consisting of two clearly distinguished phases. The first phase strongly relies on the analysis of the document structure and it is used for locating records of data in the text. The second phase is based on the finite state transducers created for extracting the data, which can be modified so as to achieve the preferred efficiency and it is used for extracting the particular characteristic from the text. We show how the two phase method is applied to the text of the encyclopaedia “Systematic Bacteriology”. A fully structured database with genotype and phenotype characteristics of organisms has been created from the encyclopaedia unstructured descriptions.

  1. Sensitivity-Bandwidth Limit in a Multimode Optoelectromechanical Transducer

    Science.gov (United States)

    Moaddel Haghighi, I.; Malossi, N.; Natali, R.; Di Giuseppe, G.; Vitali, D.

    2018-03-01

    An optoelectromechanical system formed by a nanomembrane capacitively coupled to an L C resonator and to an optical interferometer has recently been employed for the highly sensitive optical readout of rf signals [T. Bagci et al., Nature (London) 507, 81 (2013), 10.1038/nature13029]. We propose and experimentally demonstrate how the bandwidth of such a transducer can be increased by controlling the interference between two electromechanical interaction pathways of a two-mode mechanical system. With a proof-of-principle device operating at room temperature, we achieve a sensitivity of 300 nV /√{Hz } over a bandwidth of 15 kHz in the presence of radio-frequency noise, and an optimal shot-noise-limited sensitivity of 10 nV /√{Hz } over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multimode transducer can achieve a bandwidth significantly larger than that for a single-mode one.

  2. Folding and Function of Proteorhodopsins in Photoenergy Transducing Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Spudich, John L. [University of Texas Medical School, Houston, TX (United States). Health Science Center, Dept. of Biochemistry and Molecular Biology

    2012-08-10

    The overall research objectives are to develop proteorhodopsin (PR) proteins as a model system for α-helical membrane protein insertion and folding, and to advance understanding of the diversity and mechanisms of PRs, a large family of photoenergy transducers (~4000 identified) abundant in the world’s oceans. Specific aims are: (1) To develop a high-efficiency genetic selection procedure for light-driven proton-pumping in E. coli cells. Such a procedure would provide a positive selection method for proper folding and function of PRs in the E. coli membrane. (2) Characterize flash-induced absorption changes and photocurrents in PR variants in organisms from various environments, and their expression level and function when expressed in E. coli. Subaims are to: (a) elucidate the relationship of the transport mechanism to mechanisms of other microbial rhodopsins, some of which like PRs function as ion transporters and some of which use light energy to activate signaling pathways (sensory rhodopsins); and (b) identify important residues and chemical events in light-driven proton transport by PRs. In addition to their importance to the energy of the biosphere PRs have attracted interest for their potential for use in making photoenergy-transducing membranes for bioengineering applications.

  3. A ring transducer system for medical ultrasound research.

    Science.gov (United States)

    Waag, Robert C; Fedewa, Russell J

    2006-10-01

    An ultrasonic ring transducer system has been developed for experimental studies of scattering and imaging. The transducer consists of 2048 rectangular elements with a 2.5-MHz center frequency, a 67% -6 dB bandwidth, and a 0.23-mm pitch arranged in a 150-mm-diameter ring with a 25-mm elevation. At the center frequency, the element size is 0.30lambda x 42lambda and the pitch is 0.38lambda. The system has 128 parallel transmit channels, 16 parallel receive channels, a 2048:128 transmit multiplexer, a 2048:16 receive multiplexer, independently programmable transmit waveforms with 8-bit resolution, and receive amplifiers with time variable gain independently programmable over a 40-dB range. Receive signals are sampled at 20 MHz with 12-bit resolution. Arbitrary transmit and receive apertures can be synthesized. Calibration software minimizes system nonidealities caused by noncircularity of the ring and element-to-element response differences. Application software enables the system to be used by specification of high-level parameters in control files from which low-level hardware-dependent parameters are derived by specialized code. Use of the system is illustrated by producing focused and steered beams, synthesizing a spatially limited plane wave, measuring angular scattering, and forming b-scan images.

  4. An overheight vehicle bridge collision monitoring system using piezoelectric transducers

    Science.gov (United States)

    Song, G.; Olmi, C.; Gu, H.

    2007-04-01

    With increasing traffic volume follows an increase in the number of overheight truck collisions with highway bridges. The detection of collision impact and evaluation of the impact level is a critical issue in the maintenance of a concrete bridge. In this paper, an overheight collision detection and evaluation system is developed for concrete bridge girders using piezoelectric transducers. An electric circuit is designed to detect the impact and to activate a digital camera to take photos of the offending truck. Impact tests and a health monitoring test were conducted on a model concrete bridge girder by using three piezoelectric transducers embedded before casting. From the experimental data of the impact test, it can be seen that there is a linear relation between the output of sensor energy and the impact energy. The health monitoring results show that the proposed damage index indicates the level of damage inside the model concrete bridge girder. The proposed overheight truck-bridge collision detection and evaluation system has the potential to be applied to the safety monitoring of highway bridges.

  5. Two high accuracy digital integrators for Rogowski current transducers

    Science.gov (United States)

    Luo, Pan-dian; Li, Hong-bin; Li, Zhen-hua

    2014-01-01

    The Rogowski current transducers have been widely used in AC current measurement, but their accuracy is mainly subject to the analog integrators, which have typical problems such as poor long-term stability and being susceptible to environmental conditions. The digital integrators can be another choice, but they cannot obtain a stable and accurate output for the reason that the DC component in original signal can be accumulated, which will lead to output DC drift. Unknown initial conditions can also result in integral output DC offset. This paper proposes two improved digital integrators used in Rogowski current transducers instead of traditional analog integrators for high measuring accuracy. A proportional-integral-derivative (PID) feedback controller and an attenuation coefficient have been applied in improving the Al-Alaoui integrator to change its DC response and get an ideal frequency response. For the special design in the field of digital signal processing, the improved digital integrators have better performance than analog integrators. Simulation models are built for the purpose of verification and comparison. The experiments prove that the designed integrators can achieve higher accuracy than analog integrators in steady-state response, transient-state response, and temperature changing condition.

  6. Sensitivity analysis for improving nanomechanical photonic transducers biosensors

    International Nuclear Information System (INIS)

    Fariña, D; Álvarez, M; Márquez, S; Lechuga, L M; Dominguez, C

    2015-01-01

    The achievement of high sensitivity and highly integrated transducers is one of the main challenges in the development of high-throughput biosensors. The aim of this study is to improve the final sensitivity of an opto-mechanical device to be used as a reliable biosensor. We report the analysis of the mechanical and optical properties of optical waveguide microcantilever transducers, and their dependency on device design and dimensions. The selected layout (geometry) based on two butt-coupled misaligned waveguides displays better sensitivities than an aligned one. With this configuration, we find that an optimal microcantilever thickness range between 150 nm and 400 nm would increase both microcantilever bending during the biorecognition process and increase optical sensitivity to 4.8   ×   10 −2  nm −1 , an order of magnitude higher than other similar opto-mechanical devices. Moreover, the analysis shows that a single mode behaviour of the propagating radiation is required to avoid modal interference that could misinterpret the readout signal. (paper)

  7. Phononic Crystal Waveguide Transducers for Nonlinear Elastic Wave Sensing.

    Science.gov (United States)

    Ciampa, Francesco; Mankar, Akash; Marini, Andrea

    2017-11-07

    Second harmonic generation is one of the most sensitive and reliable nonlinear elastic signatures for micro-damage assessment. However, its detection requires powerful amplification systems generating fictitious harmonics that are difficult to discern from pure nonlinear elastic effects. Current state-of-the-art nonlinear ultrasonic methods still involve impractical solutions such as cumbersome signal calibration processes and substantial modifications of the test component in order to create material-based tunable harmonic filters. Here we propose and demonstrate a valid and sensible alternative strategy involving the development of an ultrasonic phononic crystal waveguide transducer that exhibits both single and multiple frequency stop-bands filtering out fictitious second harmonic frequencies. Remarkably, such a sensing device can be easily fabricated and integrated on the surface of the test structure without altering its mechanical and geometrical properties. The design of the phononic crystal structure is supported by a perturbative theoretical model predicting the frequency band-gaps of periodic plates with sinusoidal corrugation. We find our theoretical findings in excellent agreement with experimental testing revealing that the proposed phononic crystal waveguide transducer successfully attenuates second harmonics caused by the ultrasonic equipment, thus demonstrating its wide range of potential applications for acousto/ultrasonic material damage inspection.

  8. Iron-free moving coil high temperature displacement transducer

    Energy Technology Data Exchange (ETDEWEB)

    Grindrod, A

    1976-07-01

    A unique, iron free, moving coil linear displacement transducer system is described, which is suitable for continuously monitoring linear movements, at varying temperatures up to 750/sup 0/C, in operational nuclear reactors. Although this device has been primarily developed for Advanced Gas Cooled Reactor Systems, it also has uses where long term measurements on conventional high temperature plant are required. Furthermore it could be particularly useful in material creep laboratories where precise linear changes in specimen length need to be monitored at elevated temperatures, over several years. Since individual transducer installations demand specific mounting arrangements to suit particular component geometries, evaluations have been made only on standard operational modules or capsules which are designed for containment in a range of housing or fixtures to suit particular applications. The behaviour of these devices has been studied at temperatures up to 750/sup 0/C for periods of over 10,000 h. An evaluation is also included of a commercially designed sensor assembly employing the same principle, for monitoring the boiler-shield wall movement at Hinkley Point 'B' AGR Station.

  9. Design of HIFU Transducers to Generate Specific Nonlinear Ultrasound Fields

    Science.gov (United States)

    Khokhlova, Vera A.; Yuldashev, Petr V.; Rosnitskiy, Pavel B.; Maxwell, Adam D.; Kreider, Wayne; Bailey, Michael R.; Sapozhnikov, Oleg A.

    Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation oftissue. In this work, an inverse problem of determining transducer parameters to enable formation of shockswith desired amplitude at the focus is solved. The solution was obtained by performing multipledirect simulations of the parabolic Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sourcesas well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocksare formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90-100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University.

  10. Echo signal from rough planar interfaces influence of roughness, angle, range and transducer type

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Pedersen, P.C.; Jacobsen, S.M.

    1998-01-01

    The received electrical signal from a pulse-echo system insonifying a planar acoustical interface was measured for varying degrees of rms roughness (0-0.16 mm), angle of incidence (typically +/-7°) and range to the transducer. A planar and a focused 5 MHz transducer was used. When insonifying...... a smooth interface, the normalized spectrum of the received signals for a planar transducer exhibits an increasing number of nulls with increased angle of insonification, as predicted from numerical modeling while the dependence on insonification angle for the focused transducer was smaller and the null...... pattern was much less distinct. For the planar transducer and for the focused transducer with the interface located at the geometrical point of focus, the energy of the received signal as a function of incident angle was approximately Gaussian with maximum at 0°. For the smooth interface, the -3 dB width...

  11. High-frequency Doppler ultrasound transducer for the peripheral circulatory system

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2011-12-15

    A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

  12. High-frequency Doppler ultrasound transducer for the peripheral circulatory system

    International Nuclear Information System (INIS)

    Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon

    2011-01-01

    A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

  13. Class H power amplifier for power saving in fluxgate current transducers

    OpenAIRE

    Velasco Quesada, Guillermo; Román Lumbreras, Manuel; Pérez Delgado, Raul; Conesa Roca, Alfons

    2016-01-01

    This paper presents a new improvement in the design of a fluxgate-based current transducer in order to reduce the power consumption of control electronics. The proposed improvement involves the replacement of the output linear amplifier of the transducer by a class H amplifier. The output amplifier is devoted to the magnetic flux compensation and generates the transducer output current, which is proportional to the current to be measured. In this way, it is possible to reduce significantly th...

  14. Effect of planecta and ROSE? on the frequency characteristics of blood pressure-transducer kits

    OpenAIRE

    Fujiwara, Shigeki; Kawakubo, Yoshifumi; Mori, Satoshi; Tachihara, Keiichi; Toyoguchi, Izumi; Yokoyama, Takeshi

    2014-01-01

    Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE?, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and the...

  15. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2015-01-01

    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  16. Detection and generation of first sound in4He by vibrating superleak transducers

    Science.gov (United States)

    Giordano, N.; Edison, N.

    1986-07-01

    Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid4He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation.

  17. Detection and generation of first sound in 4He by vibrating superleak transducers

    International Nuclear Information System (INIS)

    Giordano, N.; Edison, N.

    1986-01-01

    Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid 4 He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation

  18. A Float Type Liquid Level Measuring System Using a Modified Inductive Transducer

    Directory of Open Access Journals (Sweden)

    Samik MARICK

    2014-11-01

    Full Text Available Float type liquid level sensor is generally used as a very simple technique for local level indication and level switching. In the present paper a technique has been proposed to transmit the measured liquid level signal of a float type sensor at remote terminal using a modified differential inductance type electromechanical transducer. The theoretical characteristic equation of this transducer has been derived. A prototype unit of the transducer has been developed and fabricated and its performance characteristic has been experimentally determined. The experimental results are reported in the paper. From experimental data, a very good linear characteristic of the proposed level transducer has been observed.

  19. A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications...... is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz – 3.5 kHz). THD+N below 0.1% are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 95 %....

  20. New improvement of the combined optical fiber transducer for landslide monitoring

    Science.gov (United States)

    Zhu, Z.-W.; Yuan, Q.-Y.; Liu, D.-Y.; Liu, B.; Liu, J.-C.; Luo, H.

    2014-08-01

    Landslide monitoring is important in predicting the behavior of landslides, thereby ensuring environmental, life, and property safety. On the basis of our previous studies, we conducted the double shear test by using a third-generation optical fiber transducer that uses expandable polystyrene (EPS) as base material. However, the third-generation transducer has poor performance when cohesive force is present between the grout and capillary stainless steel pipe of the transducer. Thus, the fourth-generation optical fiber transducer was invented. Similar to the third-generation transducer, the fourth-generation transducer also used EPS as its base material. Single shear test was conducted on the fourth-generation transducer after being grouted with cement mortar (1 : 1 mix ratio). The micro-bend loss mechanism of the optical fiber was considered, and the optical time domain reflectometry instrument was used. The fact that the loss sequence of optical fibers subjected to loading is different at various locations is found. The relationship of the loading-point displacement vs. optical fiber sliding distance and optical loss were measured. Results show that the maximum initial measurement precision of the newly proposed device is 1 mm, the corresponding sliding distance is 21 mm, and the dynamic range is 0-20 mm. The fourth-generation transducer can measure the movement direction of loadings, thus making this transducer applicable for landslide monitoring.

  1. Polarization Control with Piezoelectric and LiNbO3 Transducers

    Science.gov (United States)

    Bradley, E.; Miles, E.; Loginov, B.; Vu, N.

    Several Polarization control transducers have appeared on the market, and now automated, endless polarization control systems using these transducers are becoming available. Unfortunately it is not entirely clear what benchmark performance tests a polarization control system must pass, and the polarization disturbances a system must handle are open to some debate. We present quantitative measurements of realistic polarization disturbances and two benchmark tests we have successfully used to evaluate the performance of an automated, endless polarization control system. We use these tests to compare the performance of a system using piezoelectric transducers to that of a system using LiNbO3 transducers.

  2. On-chip RF-to-optical transducer (Conference Presentation)

    Science.gov (United States)

    Simonsen, Anders; Tsaturyan, Yeghishe; Seis, Yannick; Schmid, Silvan; Schliesser, Albert; Polzik, Eugene S.

    2016-04-01

    techniques. We will furthermore present ongoing work to couple our transducer to an RF or microwave antenna, for low-noise detection of electromagnetic signals, including sensitive measurements of magnetic fields in an MRI detector. Suppression of thermomechanical noise is a key feature of electro-optomechanical transducers, and, more generally, hybrid systems involving mechanical degrees of freedom. We have shown that engineering of the phononic density of states allows improved isolation of the relevant mechanical modes from their thermal bath [2], enabling coherence times sufficient to realize quantum-coherent optomechanical coupling. This proves the potential of the employed platform for complex transducers all the way into the quantum regime. References: [1] Bagci et al, Nature 507, 81-85, (06 March 2014) [2] Tsaturyan, et al., Optics Express, Vol. 22, Issue 6, pp. 6810-6821 (2014)

  3. Dynamic hysteretic sensing model of bending-mode Galfenol transducer

    International Nuclear Information System (INIS)

    Cao, Shuying; Zheng, Jiaju; Sang, Jie; Zhang, Pengfei; Wang, Bowen; Huang, Wenmei

    2015-01-01

    A dynamic hysteretic sensing model has been developed to predict the dynamic responses of the magnetic induction, the stress, and the output voltage for a bending-mode Galfenol unimorph transducer subjected simultaneously to acceleration and bias magnetic field. This model is obtained by coupling the hysteretic Armstrong model and the structural dynamic model of the Galfenol unimorph beam. The structural dynamic model of the beam is founded based on the Euler-Bernouli beam theory, the nonlinear constitutive equations, and the Faraday law of electromagnetic induction. Comparisons between the calculated and measured results show the model can describe dynamic nonlinear voltage characteristics of the device, and can predict hysteretic behaviors between the magnetic induction and the stress. Moreover, the model can effectively analyze the effects of the bias magnetic field, the acceleration amplitude, and frequency on the root mean square voltage of the device

  4. A distributed transducer system for functional electrical stimulation

    DEFF Research Database (Denmark)

    Gudnason, Gunnar; Nielsen, Jannik Hammel; Bruun, Erik

    2001-01-01

    to be affected by the inductive link. Neural stimulators are affected to a lesser degree, but still benefit from the partitioning. As a test case, we have designed a transceiver and a sensor chip which implement this partitioning policy. The transceiver is designed to operate in the 6.78 MHz ISM band......Implanted transducers for functional electrical stimulation (FES) powered by inductive links are subject to conflicting requirements arising from low link efficiency, a low power budget and the need for protection of the weak signals against strong RF electromagnetic fields. We propose a solution...... to these problems by partitioning the RF transceiver and sensor/actuator functions onto separate integrated circuits. By amplifying measured neural signals directly at the measurements site and converting them into the digital domain before passing them to the transceiver the signal integrity is less likely...

  5. Research on recognition of ramp angle based on transducer

    Directory of Open Access Journals (Sweden)

    Wenhao GU

    2015-12-01

    Full Text Available Focusing on the recognition of ramp angle, the relationship between the signal of vehicle transducer and real ramp angle is studied. The force change of vehicle on the ramp, and the relationship between the body tilt angle and front and rear suspension scale is discussed. According to the suspension and tire deformation, error angle of the ramp angle is deduced. A mathematical model is established with Matlab/Simulink and used for simulation to generate error curve of ramp angle. The results show that the error angle increases with the increasing of the ramp angle, and the limit value can reach 6.5%, while the identification method can effectively eliminate this error, and enhance the accuracy of ramp angle recognition.

  6. Electromagnetic acoustic transducers noncontacting ultrasonic measurements using EMATS

    CERN Document Server

    Hirao, Masahiko

    2017-01-01

    This second edition provides comprehensive information on electromagnetic acoustic transducers (EMATs), from the theory and physical principles of EMATs to the construction of systems and their applications to scientific and industrial ultrasonic measurements on materials. The original version has been complemented with selected ideas on ultrasonic measurement that have emerged since the first edition was released. The book is divided into four parts: PART I offers a self-contained description of the basic elements of coupling mechanisms along with the practical designing of EMATs for various purposes. Several implementations to compensate for EMATs’ low transfer efficiency are provided, along with useful tips on how to make an EMAT. PART II describes the principle of electromagnetic acoustic resonance (EMAR), which makes the most of EMATs’ contactless nature and is the most successful amplification mechanism for precise measurements of velocity and attenuation. PART III applies EMAR to studying physical ...

  7. Smooth driving of Mössbauer electromechanical transducers

    International Nuclear Information System (INIS)

    Veiga, A.; Mayosky, M. A.; Martínez, N.; Mendoza Zélis, P.; Pasquevich, G. A.; Sánchez, F. H.

    2011-01-01

    Quality of Mössbauer spectra is strongly related to the performance of source velocity modulator. Traditional electromechanical driving techniques demand hard-edged square or triangular velocity waveforms that introduce long settling times and demand careful driver tuning. For this work, the behavior of commercial velocity transducers and drive units was studied under different working conditions. Different velocity reference waveforms in constant-acceleration, constant-velocity and programmable-velocity techniques were tested. Significant improvement in spectrometer efficiency and accuracy was achieved by replacing triangular and square hard edges with continuous smooth-shaped transitions. A criterion for best waveform selection and synchronization is presented and attainable enhancements are evaluated. In order to fully exploit this driving technique, a compact microprocessor-based architecture is proposed and a suitable data acquisition system implementation is presented. System linearity and efficiency characterization are also shown.

  8. Modeling of nonlinear responses for reciprocal transducers involving polarization switching

    DEFF Research Database (Denmark)

    Willatzen, Morten; Wang, Linxiang

    2007-01-01

    Nonlinearities and hysteresis effects in a reciprocal PZT transducer are examined by use of a dynamical mathematical model on the basis of phase-transition theory. In particular, we consider the perovskite piezoelectric ceramic in which the polarization process in the material can be modeled...... by Landau theory for the first-order phase transformation, in which each polarization state is associated with a minimum of the Landau free-energy function. Nonlinear constitutive laws are obtained by using thermodynamical equilibrium conditions, and hysteretic behavior of the material can be modeled...... intrinsically. The time-dependent Ginzburg-Landau theory is used in the parameter identification involving hysteresis effects. We use the Chebyshev collocation method in the numerical simulations. The elastic field is assumed to be coupled linearly with other fields, and the nonlinearity is in the E-D coupling...

  9. Nonlinear ultrasonic fatigue crack detection using a single piezoelectric transducer

    Science.gov (United States)

    An, Yun-Kyu; Lee, Dong Jun

    2016-04-01

    This paper proposes a new nonlinear ultrasonic technique for fatigue crack detection using a single piezoelectric transducer (PZT). The proposed technique identifies a fatigue crack using linear (α) and nonlinear (β) parameters obtained from only a single PZT mounted on a target structure. Based on the different physical characteristics of α and β, a fatigue crack-induced feature is able to be effectively isolated from the inherent nonlinearity of a target structure and data acquisition system. The proposed technique requires much simpler test setup and less processing costs than the existing nonlinear ultrasonic techniques, but fast and powerful. To validate the proposed technique, a real fatigue crack is created in an aluminum plate, and then false positive and negative tests are carried out under varying temperature conditions. The experimental results reveal that the fatigue crack is successfully detected, and no positive false alarm is indicated.

  10. Towards a visual modeling approach to designing microelectromechanical system transducers

    Science.gov (United States)

    Dewey, Allen; Srinivasan, Vijay; Icoz, Evrim

    1999-12-01

    In this paper, we address initial design capture and system conceptualization of microelectromechanical system transducers based on visual modeling and design. Visual modeling frames the task of generating hardware description language (analog and digital) component models in a manner similar to the task of generating software programming language applications. A structured topological design strategy is employed, whereby microelectromechanical foundry cell libraries are utilized to facilitate the design process of exploring candidate cells (topologies), varying key aspects of the transduction for each topology, and determining which topology best satisfies design requirements. Coupled-energy microelectromechanical system characterizations at a circuit level of abstraction are presented that are based on branch constitutive relations and an overall system of simultaneous differential and algebraic equations. The resulting design methodology is called visual integrated-microelectromechanical VHDL-AMS interactive design (VHDL-AMS is visual hardware design language for analog and mixed signal).

  11. Class D audio amplifiers for high voltage capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis

    of high volume, weight, and cost. High efficient class D amplifiers are now widely available offering power densities, that their linear counterparts can not match. Unlike the technology of audio amplifiers, the loudspeaker is still based on the traditional electrodynamic transducer invented by C.W. Rice......Audio reproduction systems contains two key components, the amplifier and the loudspeaker. In the last 20 – 30 years the technology of audio amplifiers have performed a fundamental shift of paradigm. Class D audio amplifiers have replaced the linear amplifiers, suffering from the well-known issues...... with the low level of acoustical output power and complex amplifier requirements, have limited the commercial success of the technology. Horn or compression drivers are typically favoured, when high acoustic output power is required, this is however at the expense of significant distortion combined...

  12. A Pseudo-3D Model for Electromagnetic Acoustic Transducers (EMATs

    Directory of Open Access Journals (Sweden)

    Wuliang Yin

    2018-03-01

    Full Text Available Previous methods for modelling Rayleigh waves produced by a meander-line-coil electromagnetic acoustic transducer (EMAT consisted mostly of two-dimensional (2D simulations that focussed on the vertical plane of the material. This paper presents a pseudo-three-dimensional (3D model that extends the simulation space to both vertical and horizontal planes. For the vertical plane, we combines analytical and finite-difference time-domain (FDTD methods to model Rayleigh waves’ propagation within an aluminium plate and their scattering behaviours by cracks. For the horizontal surface plane, we employ an analytical method to investigate the radiation pattern of Rayleigh waves at various depths. The experimental results suggest that the models and the modelling techniques are valid.

  13. Selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers

    International Nuclear Information System (INIS)

    Li Ming-Liang; Deng Ming-Xi; Gao Guang-Jian

    2016-01-01

    In this paper, we describe a modal expansion approach for the analysis of the selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers (EMATs). With the modal expansion approach for waveguide excitation, an analytical expression of the Lamb wave’s mode expansion coefficient is deduced, which is related to the driving frequency and the geometrical parameters of the EMAT’s meander coil, and lays a theoretical foundation for exactly analyzing the selective generation of Lamb waves with EMATs. The influences of the driving frequency on the mode expansion coefficient of ultrasonic Lamb waves are analyzed when the EMAT’s geometrical parameters are given. The numerical simulations and experimental examinations show that the ultrasonic Lamb wave modes can be effectively regulated (strengthened or restrained) by choosing an appropriate driving frequency of EMAT, with the geometrical parameters given. This result provides a theoretical and experimental basis for selectively generating a single and pure Lamb wave mode with EMATs. (special topic)

  14. On-chip RF-to-optical transducer

    DEFF Research Database (Denmark)

    Simonsen, Anders; Tsaturyan, Yeghishe; Seis, Yannick

    2016-01-01

    these diverse systems, plus technologies that utilize them, and the mature toolbox of optical techniques that routinely operates at the quantum limit. In a previous work [1], we demonstrated such a bridge by realizing simultaneous coupling between an electronic LC circuit and a quantum-noise limited optical...... noise temperatures far below the actual temperature of the mechanical element. On-chip integration of the electrical, mechanical and optical elements is necessary for an implementation of the transduction scheme that is viable for commercial applications. Reliable assembly of a strongly coupled...... electromechanical device, and inclusion of an optical cavity for enhanced optical readout, are key features of the new platform. Both can be achieved with standard cleanroom fabrication techniques. We will furthermore present ongoing work to couple our transducer to an RF or microwave antenna, for low...

  15. Campylobacter jejuni transducer like proteins: Chemotaxis and beyond.

    Science.gov (United States)

    Chandrashekhar, Kshipra; Kassem, Issmat I; Rajashekara, Gireesh

    2017-07-04

    Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials.

  16. Introduction to special session on "ultrasonic transducers for harsh environments

    Science.gov (United States)

    Tittmann, B. R.; Reinhardt, B.; Daw, J.

    2018-04-01

    This work describes the results of experiments conducted as part of an instrumented lead test in-core in a nuclear reactor with the piezoelectric and magnetostrictive materials. The experiments exposed AlN, ZnO, BiT, Remendur, and Galfenol to more neutron radiation than found in the literature. The magnetostrictive sensors produce stable ultrasonic pulse-echoes throughout much of the irradiation. The BiT transducers could operate up until approximate 5 × 10^20 n/cm^2 (E>1MeV). The piezoelectric AlN operated well during the entire experiment. The results imply that now available are candidates for operation in harsh environments found in nuclear reactors and steam generator plants.

  17. Optical detection of radio waves through a nanomechanical transducer

    DEFF Research Database (Denmark)

    Bagci, T.; Simonsen, A.; Schmid, Silvan

    2014-01-01

    Low-loss transmission and sensitive recovery of weak radio-frequency and microwave signals is a ubiquitous challenge, crucial in radio astronomy, medical imaging, navigation, and classical and quantum communication. Efficient up-conversion of radio-frequency signals to an optical carrier would...... strong coupling between the voltage fluctuations in a radio-frequency resonance circuit and the membrane's displacement, which is simultaneously coupled to light reflected off its surface. The radio-frequency signals are detected as an optical phase shift with quantum-limited sensitivity....... The corresponding half-wave voltage is in the microvolt range, orders of magnitude less than that of standard optical modulators. The noise of the transducer--beyond the measured 800 pV Hz-1/2 Johnson noise of the resonant circuit--consists of the quantum noise of light and thermal fluctuations of the membrane...

  18. Dynamic hysteretic sensing model of bending-mode Galfenol transducer

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shuying, E-mail: shuying-cao@hebut.edu.cn; Zheng, Jiaju; Sang, Jie; Zhang, Pengfei; Wang, Bowen; Huang, Wenmei [Province-Ministry Joint Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability, Hebei University of Technology, Tianjin 300130 (China)

    2015-05-07

    A dynamic hysteretic sensing model has been developed to predict the dynamic responses of the magnetic induction, the stress, and the output voltage for a bending-mode Galfenol unimorph transducer subjected simultaneously to acceleration and bias magnetic field. This model is obtained by coupling the hysteretic Armstrong model and the structural dynamic model of the Galfenol unimorph beam. The structural dynamic model of the beam is founded based on the Euler-Bernouli beam theory, the nonlinear constitutive equations, and the Faraday law of electromagnetic induction. Comparisons between the calculated and measured results show the model can describe dynamic nonlinear voltage characteristics of the device, and can predict hysteretic behaviors between the magnetic induction and the stress. Moreover, the model can effectively analyze the effects of the bias magnetic field, the acceleration amplitude, and frequency on the root mean square voltage of the device.

  19. HIFU Transducer Characterization Using a Robust Needle Hydrophone

    Science.gov (United States)

    Howard, Samuel M.; Zanelli, Claudio I.

    2007-05-01

    A robust needle hydrophone has been developed for HIFU transducer characterization and reported on earlier. After a brief review of the hydrophone design and performance, we demonstrate its use to characterize a 1.5 MHz, 10 cm diameter, F-number 1.5 spherically focused source driven to exceed an intensity of 1400 W/cm2at its focus. Quantitative characterization of this source at high powers is assisted by deconvolving the hydrophone's calibrated frequency response in order to accurately reflect the contribution of harmonics generated by nonlinear propagation in the water testing environment. Results are compared to measurements with a membrane hydrophone at 0.3% duty cycle and to theoretical calculations, using measurements of the field at the source's radiating surface as input to a numerical solution of the KZK equation.

  20. Bidirectional microwave-mechanical-optical transducer in a dilution refrigerator

    Science.gov (United States)

    Burns, Peter S.; Higginbotham, Andrew P.; Peterson, Robert W.; Urmey, Maxwell D.; Kampel, Nir S.; Menke, Timothy; Cicak, Katarina; Simmonds, Raymond. W.; Regal, Cindy A.; Lehnert, Konrad W.

    Transferring quantum states between microwave and optical networks would be a powerful resource for quantum communication and computation. Our approach is to simultaneously couple one mode of a micromechanical oscillator to a resonant microwave circuit and a high-finesse optical cavity. Building on previous work demonstrating bidirectional and efficient classical conversion at 4 K, a new microwave-to-optical transducer is operated at 0.1 K and preparations are underway to operate it in the quantum regime. To improve transfer efficiency, we characterize and implement wireless microwave access to the converter chip. Transfer efficiency of the device is measured, and loss in the LC circuit due to laser light is characterized. We acknowledge support from AFOSR MURI Grant FA9550-15-1-0015 and PFC National Science Foundation Grant 1125844.

  1. High-Temperature Surface-Acoustic-Wave Transducer

    Science.gov (United States)

    Zhao, Xiaoliang; Tittmann, Bernhard R.

    2010-01-01

    Aircraft-engine rotating equipment usually operates at high temperature and stress. Non-invasive inspection of microcracks in those components poses a challenge for the non-destructive evaluation community. A low-profile ultrasonic guided wave sensor can detect cracks in situ. The key feature of the sensor is that it should withstand high temperatures and excite strong surface wave energy to inspect surface/subsurface cracks. As far as the innovators know at the time of this reporting, there is no existing sensor that is mounted to the rotor disks for crack inspection; the most often used technology includes fluorescent penetrant inspection or eddy-current probes for disassembled part inspection. An efficient, high-temperature, low-profile surface acoustic wave transducer design has been identified and tested for nondestructive evaluation of structures or materials. The development is a Sol-Gel bismuth titanate-based surface-acoustic-wave (SAW) sensor that can generate efficient surface acoustic waves for crack inspection. The produced sensor is very thin (submillimeter), and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. One major uniqueness of the Sol-Gel bismuth titanate SAW sensor is that it is easy to implement to structures of various shapes. With a spray coating process, the sensor can be applied to surfaces of large curvatures. Second, the sensor is very thin (as a coating) and has very minimal effect on airflow or rotating equipment imbalance. Third, it can withstand temperatures up to 530 C, which is very useful for engine applications where high temperature is an issue.

  2. Reliability and Validity Assessment of a Linear Position Transducer

    Science.gov (United States)

    Garnacho-Castaño, Manuel V.; López-Lastra, Silvia; Maté-Muñoz, José L.

    2015-01-01

    The objectives of the study were to determine the validity and reliability of peak velocity (PV), average velocity (AV), peak power (PP) and average power (AP) measurements were made using a linear position transducer. Validity was assessed by comparing measurements simultaneously obtained using the Tendo Weightlifting Analyzer Systemi and T-Force Dynamic Measurement Systemr (Ergotech, Murcia, Spain) during two resistance exercises, bench press (BP) and full back squat (BS), performed by 71 trained male subjects. For the reliability study, a further 32 men completed both lifts using the Tendo Weightlifting Analyzer Systemz in two identical testing sessions one week apart (session 1 vs. session 2). Intraclass correlation coefficients (ICCs) indicating the validity of the Tendo Weightlifting Analyzer Systemi were high, with values ranging from 0.853 to 0.989. Systematic biases and random errors were low to moderate for almost all variables, being higher in the case of PP (bias ±157.56 W; error ±131.84 W). Proportional biases were identified for almost all variables. Test-retest reliability was strong with ICCs ranging from 0.922 to 0.988. Reliability results also showed minimal systematic biases and random errors, which were only significant for PP (bias -19.19 W; error ±67.57 W). Only PV recorded in the BS showed no significant proportional bias. The Tendo Weightlifting Analyzer Systemi emerged as a reliable system for measuring movement velocity and estimating power in resistance exercises. The low biases and random errors observed here (mainly AV, AP) make this device a useful tool for monitoring resistance training. Key points This study determined the validity and reliability of peak velocity, average velocity, peak power and average power measurements made using a linear position transducer The Tendo Weight-lifting Analyzer Systemi emerged as a reliable system for measuring movement velocity and power. PMID:25729300

  3. A Dual-Range Strain Gage Weighing Transducer Employing Automatic Switching

    Science.gov (United States)

    Rodger A. Arola

    1968-01-01

    Describes a dual-range strain gage transducer which has proven to be an excellent weight-sensing device for weighing trees and tree-length logs; discusses basic principals of the design and operation; and shows that a single transducer having two sensitivity ranges with automatic internal switching can sense weight with good repeatability and that one calibration curve...

  4. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    International Nuclear Information System (INIS)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Karatzas, L S

    2009-01-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  5. Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

    International Nuclear Information System (INIS)

    Lin Shuyu; Tian Hua

    2008-01-01

    A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

  6. Phased transducer array for acoustic energy harvesting inside an MRI machine

    NARCIS (Netherlands)

    Klymko, V.; Roes, M.G.L.; Duivenbode, van J.; Lomonova, E.

    2013-01-01

    In this study, an array of piezoelectric speakers is used to focus acoustic energy on a single transducer that acts as a harvester. The transmitting transducers are located along a curve that fits inside the magnetic resonance interferometer (MRI) torus interior. The numerical results for the

  7. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    Energy Technology Data Exchange (ETDEWEB)

    Hadjiloucas, S; Walker, G C; Bowen, J W [Cybernetics, School of Systems Engineering, University of Reading, RG6 6AY (United Kingdom); Karatzas, L S, E-mail: s.hadjiloucas@reading.ac.u [Temasek Polytechnic, School of Engineering, 21 Tampines Avenue 1, Singapore, 529757 (Singapore)

    2009-07-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  8. A Doubly-Curved Piezoelectric Composite with 1-3 Connectivity for Underwater Transducer Applications

    Science.gov (United States)

    Zhang, Yanjun; Wang, Likun; Qin, Lei; Liao, Qingwei; Zhong, Chao

    2018-03-01

    Aim to increase the horizontal and vertical beam width of the high frequency transducer simultaneously, we present a doubly-curved 1-3 piezoelectric composite element. It consists of 54% piezoelectric ceramic volume fraction and two phases polymer matrix. The finite element analysis (FEA) is used to evaluate the dynamic response of composite. Electroacoustic response in water was measured for the doubly-curved composite being considered as underwater transducer. An underwater transducer was fabricated using the doubly-curved 1-3 piezoelectric composite element. The -3 dB full angle beam width of transducer is approximately 106° and 36° in the horizontal and vertical plane respectively. Both the FEA simulations and experimental results show the potential of a broad covered area of the composite transducer in underwater environment.

  9. Note: Decoupling design for high frequency piezoelectric ultrasonic transducers with their clamping connections

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F. J., E-mail: wangfujun@tju.edu.cn; Liang, C. M.; Tian, Y. L.; Zhao, X. Y.; Zhang, D. W. [Tianjin Key Laboratory of Equipment Design and Manufacturing Technology, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhang, H. J. [Tianjin Key Laboratory of Modern Mechatronics Equipment Technology, School of Mechanical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2015-12-15

    This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.

  10. Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2009-10-15

    Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

  11. Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

    International Nuclear Information System (INIS)

    Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok

    2009-01-01

    Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

  12. Dissimilar trend of nonlinearity in ultrasound transducers and systems at resonance and non-resonance frequencies

    DEFF Research Database (Denmark)

    Ghasemi, Negareh; Zare, Firuz; Davari, Pooya

    2017-01-01

    Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectric...... was excited at different frequencies. Different excitation signals were generated using a linear power amplifier and a multilevel converter within a range of 30–200 V. Empirical relation was developed to express the resistance of the piezoelectric transducer as a nonlinear function of both excitation voltage...... and resonance frequency. The impedance measurements revealed that at higher voltage ranges, the piezoelectric transducer can be easily saturated. Also, it was shown that for the developed ultrasound system composed of two transducers (one transmitter and one receiver), the output voltage measured across...

  13. Ultrasonic Transducer Design for the Axial Flaw Detection of Dissimilar Metal Weld

    International Nuclear Information System (INIS)

    Yoon, Byung Sik; Kim, Yong Sik; Yang, Seung Han

    2011-01-01

    Dissimilar metal welds in nuclear power plant are known as very susceptible to PWSCC flaws, and periodically inspected by the qualified inspector and qualified procedure during in-service inspection period. According to field survey data, the majority of their DMWs are located on tapered nozzle or adjacent to a tapered component. These types of configurations restrict examination access and also limit examination volume coverage. Additionally, circumferential scan for axially oriented flaw is very difficult to detect located on tapered surface because the transducer can't receive flaw response from reflector for miss-orientation. To overcome this miss-orientation, it is necessary adapt skewed ultrasonic transducer accommodate tapered surface. The skewed refracted longitudinal ultrasonic transducer designed by modeling and manufactured from the modelling result for axial flaw detection. Experimental results showed that the skewed refracted longitudinal ultrasonic transducer get higher flaw response than non-skewed refracted longitudinal ultrasonic transducer

  14. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

    2015-12-15

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  15. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik

    2013-01-01

    We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer...... change in geometry and that the coupling angle may be used as an additional tuning parameter for improved acoustophoretic control with single-frequency actuation. Further, we find that frequency-modulation actuation is suitable for diminishing such tuning effects and that it is a robust method to produce...... coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 µm diameter beads and the results with the tunable-angle...

  16. Calculation of acoustic field based on laser-measured vibration velocities on ultrasonic transducer surface

    Science.gov (United States)

    Hu, Liang; Zhao, Nannan; Gao, Zhijian; Mao, Kai; Chen, Wenyu; Fu, Xin

    2018-05-01

    Determination of the distribution of a generated acoustic field is valuable for studying ultrasonic transducers, including providing the guidance for transducer design and the basis for analyzing their performance, etc. A method calculating the acoustic field based on laser-measured vibration velocities on the ultrasonic transducer surface is proposed in this paper. Without knowing the inner structure of the transducer, the acoustic field outside it can be calculated by solving the governing partial differential equation (PDE) of the field based on the specified boundary conditions (BCs). In our study, the BC on the transducer surface, i.e. the distribution of the vibration velocity on the surface, is accurately determined by laser scanning measurement of discrete points and follows a data fitting computation. In addition, to ensure the calculation accuracy for the whole field even in an inhomogeneous medium, a finite element method is used to solve the governing PDE based on the mixed BCs, including the discretely measured velocity data and other specified BCs. The method is firstly validated on numerical piezoelectric transducer models. The acoustic pressure distributions generated by a transducer operating in an homogeneous and inhomogeneous medium, respectively, are both calculated by the proposed method and compared with the results from other existing methods. Then, the method is further experimentally validated with two actual ultrasonic transducers used for flow measurement in our lab. The amplitude change of the output voltage signal from the receiver transducer due to changing the relative position of the two transducers is calculated by the proposed method and compared with the experimental data. This method can also provide the basis for complex multi-physical coupling computations where the effect of the acoustic field should be taken into account.

  17. Improvement of amperometric transducer selectivity using nanosized phenylenediamine films

    Science.gov (United States)

    Soldatkina, O. V.; Kucherenko, I. S.; Pyeshkova, V. M.; Alekseev, S. A.; Soldatkin, O. O.; Dzyadevych, S. V.

    2017-11-01

    In this work, we studied the conditions of deposition of a semipermeable polyphenylenediamine (PPD)-based membrane on amperometric disk platinum electrodes. Restricting an access of interfering substances to the electrode surface, the membrane prevents their impact on the sensor operation. Two methods of membrane deposition by electropolymerization were compared—at varying potential (cyclic voltammetry) and at constant potential. The cyclic voltammetry was shown to be easier in performing and providing better properties of the membrane. The dependence of PPD membrane effectiveness on the number of cyclic voltammograms and phenylenediamine concentration was analyzed. It was shown that the impact of interfering substances (ascorbic acid, dopamine, cysteine, uric acid) on sensor operation could be completely avoided using three cyclic voltammograms in 30 mM phenylenediamine. On the other hand, when working with diluted samples, i.e., at lower concentrations of electroactive substances, it is reasonable to decrease the phenylenediamine concentration to 5 mM, which would result in a higher sensitivity of transducers to hydrogen peroxide due to a thinner PPD layer. The PPD membrane was tested during continuous operation and at 8-day storage and turned out to be efficient in sensor and biosensors.

  18. The Evolution of Energy-Transducing Systems. Studies with Archaebacteria

    Science.gov (United States)

    Stan-Lotter, Helga

    1996-01-01

    The dicyclohexyl carbodiimide (DCCD)- binding site of the membrane ATPase from Halobacterium saccharovorum was investigated during earlier periods of this Cooperative Agreement and was localized to a cyanogen bromide fragment of subunit 2 from amino acids 379 (Glu) to 442 (Met). Although the exact position of the reactive amino acid (probably a glutamic acid) has not yet been determined, the data, together with recently obtained immuno reactions and sequences of Cyanogen Bromide (CNBr) fragments from E.coli F-ATPase, suggested subunit interactions in the halobacterial ATPase which had not been recognized before. They also provided evidence for the presence of a gamma subunit in the halobacterial ATPase, and for a stretch of a amino acids similar to the 'catch' between beta and gamma in bovine F-ATPase. The evolutionary implications of these findings are twofold: first, halobacterial (or archaebacterial) ATPases appear as complex as those from higher organisms - no simpler versions of these membrane enzymes are known to date; second, a monophyletic origin of the energy-transducing ATPases is becoming more apparent, and - together with other data - the split into V- and F-ATPases may have occurred much later than had been previously thought (i.e., after the split into Archaea and Bacteria). Other work included the characterization of an extremely halophilic isolate (Halococcus salifodinae ) from Permian salt sediments. This organism appeared to be an autotrophic halobacterium; its incorporation of C02 was investigated.

  19. Development of inter digital transducers to the control structures

    International Nuclear Information System (INIS)

    Takpara, R.; Fall, D.; Duquennoy, M.; Ouaftouh, M.; Courtois, C.; Rguiti, M.; Gonon, M.; Maurye, N.; Martic, G.; Lardot, V.; Seronveaux, L.; Halleux, J.; Pelegris, C.; Guessasma, M.

    2015-01-01

    This work deals with the realization of interdigital transducers (IDT) in order to characterize the quality of coatings and surfaces of structures. The challenge of this study is three fold. Firstly, the aim is to have efficient sensors to generate surface acoustic wave (SAW) since these wave sare well suited for this type of characterization. The second objective ofthis study is to provide flexible sensors so that they can adapt to different shapes of structures. Finally, relatively inexpensive technologies are favored for the development of these sensors because this allows continuous monitoring (structural health monitoring) by incorporating these sensors permanently on the structures to be tested. To meet these goals, several French and Belgian laboratories have gathered around the PRISTIFLEX project INTERREG IV. After a presentation of the manufacturing process and the characteristics of the piezo electric material developed in this study, we discussed modeling which helped to define the dimensional parameters of the piezo electric plate that composes the sensor. Then, the techniques for producing the electrodes (laserablation and inkjet printing) were presented and an example of performed electrode was provided. Finally, the effectiveness of these sensors from the measurement of the displacement caused by the surface wave excited by these IDT sensors were demonstrated. (author)

  20. Acoustic cavity transducers for the manipulation of cells and biomolecules

    Science.gov (United States)

    Tovar, Armando; Patel, Maulik; Lee, Abraham P.

    2010-02-01

    A novel fluidic actuator that is simple to fabricate, integrate, and operate is demonstrated for use within microfluidic systems. The actuator is designed around the use of trapped air bubbles in lateral cavities and the resultant acoustic streaming generated from an outside acoustic energy source. The orientation of the lateral cavities to the main microchannel is used to control the bulk fluid motion within the device. The first order flow generated by the oscillating bubble is used to develop a pumping platform that is capable of driving fluid within a chip. This pump is integrated into a recirculation immunoassay device for enhanced biomolecule binding through fluid flow for convection limited transport. The recirculation system showed an increase in binding site concentration when compared with traditional passive and flow-through methods. The acoustic cavity transducer has also been demonstrated for application in particle switching. Bursts of acoustic energy are used to generate a second order streaming pattern near the cavity interface to drive particles away or towards the cavity. The use of this switching mechanism is being extended to the application of sorting cells and other particles within a microfluidic system.

  1. Lunar Advanced Volatile Analysis Subsystem: Pressure Transducer Trade Study

    Science.gov (United States)

    Kang, Edward Shinuk

    2017-01-01

    In Situ Resource Utilization (ISRU) is a key factor in paving the way for the future of human space exploration. The ability to harvest resources on foreign astronomical objects to produce consumables and propellant offers potential reduction in mission cost and risk. Through previous missions, the existence of water ice at the poles of the moon has been identified, however the feasibility of water extraction for resources remains unanswered. The Resource Prospector (RP) mission is currently in development to provide ground truth, and will enable us to characterize the distribution of water at one of the lunar poles. Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) is the primary payload on RP that will be used in conjunction with a rover. RESOLVE contains multiple instruments for systematically identifying the presence of water. The main process involves the use of two systems within RESOLVE: the Oxygen Volatile Extraction Node (OVEN) and Lunar Advanced Volatile Analysis (LAVA). Within the LAVA subsystem, there are multiple calculations that depend on accurate pressure readings. One of the most important instances where pressure transducers (PT) are used is for calculating the number of moles in a gas transfer from the OVEN subsystem. As a critical component of the main process, a mixture of custom and commercial off the shelf (COTS) PTs are currently being tested in the expected operating environment to eventually down select an option for integrated testing in the LAVA engineering test unit (ETU).

  2. Electronic Current Transducer (ECT) for high voltage dc lines

    Science.gov (United States)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  3. Damage Identification of Wind Turbine Blades Using Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Seong-Won Choi

    2014-01-01

    Full Text Available This paper presents the experimental results of active-sensing structural health monitoring (SHM techniques, which utilize piezoelectric transducers as sensors and actuators, for determining the structural integrity of wind turbine blades. Specifically, Lamb wave propagations and frequency response functions at high frequency ranges are used to estimate the condition of wind turbine blades. For experiments, a 1 m section of a CX-100 blade is used. The goal of this study is to assess and compare the performance of each method in identifying incipient damage with a consideration given to field deployability. Overall, these methods yielded a sufficient damage detection capability to warrant further investigation. This paper also summarizes the SHM results of a full-scale fatigue test of a 9 m CX-100 blade using piezoelectric active sensors. This paper outlines considerations needed to design such SHM systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations.

  4. Bio-applications of ionic polymer metal composite transducers

    International Nuclear Information System (INIS)

    Aw, K C; McDaid, A J

    2014-01-01

    Traditional robotic actuators have advanced performance which in some aspects can surpass that of humans, however they are lacking when it comes to developing devices which are capable of operating together with humans. Bio-inspired transducers, for example ionic polymer metal composites (IPMC), which have similar properties to human tissue and muscle, demonstrate much future promise as candidates for replacing traditional robotic actuators in medical robotics applications. This paper outlines four biomedical robotics applications, an IPMC stepper motor, an assistive glove exoskeleton/prosthetic hand, a surgical robotic tool and a micromanipulation system. These applications have been developed using mechanical design/modelling techniques with IPMC ‘artificial muscle’ as the actuation system. The systems are designed by first simulating the performance using an IPMC model and dynamic models of the mechanical system; the appropriate advanced adaptive control schemes are then implemented to ensure that the IPMCs operate in the correct manner, robustly over time. This paper serves as an overview of the applications and concludes with some discussion on the future challenges of developing real-world IPMC applications

  5. Language Model Combination and Adaptation Using Weighted Finite State Transducers

    Science.gov (United States)

    Liu, X.; Gales, M. J. F.; Hieronymus, J. L.; Woodland, P. C.

    2010-01-01

    In speech recognition systems language model (LMs) are often constructed by training and combining multiple n-gram models. They can be either used to represent different genres or tasks found in diverse text sources, or capture stochastic properties of different linguistic symbol sequences, for example, syllables and words. Unsupervised LM adaption may also be used to further improve robustness to varying styles or tasks. When using these techniques, extensive software changes are often required. In this paper an alternative and more general approach based on weighted finite state transducers (WFSTs) is investigated for LM combination and adaptation. As it is entirely based on well-defined WFST operations, minimum change to decoding tools is needed. A wide range of LM combination configurations can be flexibly supported. An efficient on-the-fly WFST decoding algorithm is also proposed. Significant error rate gains of 7.3% relative were obtained on a state-of-the-art broadcast audio recognition task using a history dependently adapted multi-level LM modelling both syllable and word sequences

  6. Bio-applications of ionic polymer metal composite transducers

    Science.gov (United States)

    Aw, K. C.; McDaid, A. J.

    2014-07-01

    Traditional robotic actuators have advanced performance which in some aspects can surpass that of humans, however they are lacking when it comes to developing devices which are capable of operating together with humans. Bio-inspired transducers, for example ionic polymer metal composites (IPMC), which have similar properties to human tissue and muscle, demonstrate much future promise as candidates for replacing traditional robotic actuators in medical robotics applications. This paper outlines four biomedical robotics applications, an IPMC stepper motor, an assistive glove exoskeleton/prosthetic hand, a surgical robotic tool and a micromanipulation system. These applications have been developed using mechanical design/modelling techniques with IPMC ‘artificial muscle’ as the actuation system. The systems are designed by first simulating the performance using an IPMC model and dynamic models of the mechanical system; the appropriate advanced adaptive control schemes are then implemented to ensure that the IPMCs operate in the correct manner, robustly over time. This paper serves as an overview of the applications and concludes with some discussion on the future challenges of developing real-world IPMC applications.

  7. A rotary piezoelectric actuator using longitudinal and bending hybrid transducer

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    2012-12-01

    Full Text Available A rotary piezoelectric actuator using bolt-clamped type transducer with double driving feet is proposed in this study. The first-order longitudinal and fourth-order bending vibration modes are superimposed in the actuator to produce elliptical movements on the driving tips. Longitudinal PZT and bending PZT are clamped between the exponential shape horns and the flange by bolts. The vibration shape changes of the actuator are presented to give a clear explanation of its working principle. Several structural parameters of the exponential shape horn are selected and adjusted to accomplish the tuning process of the longitudinal and bending resonance frequencies. The input impedance and vibration characteristics are calculated by using FEM method; the gained results verify the feasibility of the proposed actuator. After the fabrication of a prototype, its vibration characteristics are measured by using a scanning laser Doppler vibrometer; the tested results are in good agreement with the FEM calculated results. The mechanical output performance experiments state that the prototype achieves a maximum speed of 129 r/min and a maximum torque of 1.5 Nm.

  8. Variable reluctance displacement transducer temperature compensated to 6500F

    International Nuclear Information System (INIS)

    1975-01-01

    In pressurized water reactor tests, compact instruments for accurate measurement of small displacements in a 650 0 F environment are often required. In the case of blowdown tests such as the Loss of Fluid Test (LOFT) or Semiscale computer code development tests, not only is the initial environment water at 650 0 F and 2200 psi but it undergoes a severe transient due to depressurization. Since the LOFT and Semiscale tests are run just for the purpose of obtaining data during the depressurization, instruments used to obtain the data must not give false outputs induced by the change in environment. A LOFT rho v 2 probe and a Semiscale drag disk are described. Each utilizes a variable reluctance transducer (VRT) for indication of the drag-disk location and a torsion bar for drag-disk restoring force. The VRT, in addition to being thermally gain and null offset stable, is fabricated from materials known to be resistant to large nuclear radiation levels and has successfully passed a fast neutron radiation test of 2.7 x 10 17 nvt without failure

  9. Resonant gravimetric immunosensing based on capacitive micromachined ultrasound transducers

    KAUST Repository

    Viržonis, Darius

    2014-04-08

    High-frequency (40 MHz) and low-frequency (7 MHz) capacitive micromachined ultrasound transducers (CMUT) were fabricated and tested for use in gravimetric detection of biomolecules. The low-frequency CMUT sensors have a gold-coated surface, while the high-frequency sensors have a silicon nitride surface. Both surfaces were functionalized with bovine leukemia virus antigen gp51 acting as the antigen. On addition of an a specific antibody labeled with horseradish peroxidase (HRP), the antigen/antibody complex is formed on the surface and quantified by HRP-catalyzed oxidation of tetramethylbenzidine. It has been found that a considerably smaller quantity of immuno complex is formed on the high frequency sensor surface. In parallel, the loading of the surface of the CMUT was determined via resonance frequency and electromechanical resistance readings. Following the formation of the immuno complexes, the resonance frequencies of the low-frequency and high-frequency sensors decrease by up to 420 and 440 kHz, respectively. Finite element analysis reveals that the loading of the (gold-coated) low frequency sensors is several times larger than that on high frequency sensors. The formation of the protein film with pronounced elasticity and stress on the gold surface case is discussed. We also discuss the adoption of this method for the detection of DNA using a hybridization assay following polymerase chain reaction.

  10. Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer

    Directory of Open Access Journals (Sweden)

    Jie Xu

    2017-12-01

    Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.

  11. Structural model of standard ultrasonic transducer array developed for FEM analysis of mechanical crosstalk.

    Science.gov (United States)

    Celmer, M; Opieliński, K J; Dopierała, M

    2018-02-01

    One of the reasons of distortions in ultrasonic imaging are crosstalk effects. They can be divided into groups according to the way of their formation. One of them is constituted by mechanical crosstalk, which is propagated by a construction of a multi-element array of piezoelectric transducers. When an individual transducer is excited, mechanical vibrations are transferred to adjacent construction components, thereby stimulating neighboring transducers to an undesired operation. In order to explore ways of the propagation of such vibrations, the authors developed the FEM model of the array of piezoelectric transducers designed for calculations in COMSOL Multiphysics software. Simulations of activating individual transducers and calculated electrical voltages appearing on transducers unstimulated intentionally, were performed in the time domain in order to assess the propagation velocity of different vibration modes through the construction elements. On this basis, conclusions were drawn in terms of the participation of various construction parts of the array of piezoelectric transducers in the process of creating the mechanical crosstalk. The elaborated FEM model allowed also to examine the ways aimed at reducing the transmission of mechanical crosstalk vibrations through the components of the array. Studies showed that correct cuts in the fasteners and the front layer improve the reduction of the mechanical crosstalk effect. The model can become a helpful tool in the process of design and modifications of manufactured ultrasonic arrays particularly in terms of mechanical crosstalk reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. A rectangle-type linear ultrasonic motor using longitudinal vibration transducers with four driving feet.

    Science.gov (United States)

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2013-04-01

    To make full use of the vibrational energy of a longitudinal transducer, a rectangle-type linear ultrasonic motor with four driving feet is proposed in this paper. This new motor consists of four longitudinal vibration transducers which are arranged in a rectangle and form an enclosed construction. Lead zirconate titanate ceramics are embedded into the middle of the transducer and fastened by a wedge-caulking mechanism. Each transducer includes an exponentially shaped horn located on each end. The horns of the vertical transducers intersect at the base of the horizontal transducers' horns; the tip ends of the horizontal transducers' horns are used as the driving feet. Longitudinal vibrations are superimposed in the motor and generate elliptical movements at the tip ends of the horns. The working principle of the proposed motor is analyzed. The resonance frequencies of two working modes are tuned to be close to each other by adjusting the structural parameters. Transient analysis is developed to gain the vibration characteristics of the motor. A prototype motor is fabricated and measured. The vibration test results verify the feasibility of the proposed design. Typical output of the prototype is a no-load speed of 928 mm/s and maximum thrust force of 60 N at a voltage of 200 Vrms.

  13. High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2014-07-01

    Full Text Available Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3O3-PbTiO3 (PMN-PT have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60% near the morphotropic phase boundary (MPB. Ternary Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 (PIN-PMN-PT single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

  14. Thermal effects on transducer material for heat assisted magnetic recording application

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Rong, E-mail: Ji-Rong@dsi.a-star.edu.sg; Xu, Baoxi; Cen, Zhanhong; Ying, Ji Feng; Toh, Yeow Teck [Data Storage Institute, Agency for Science, Technology and Research (A-STAR), 5 Engineering Drive 1, Singapore 117608 (Singapore)

    2015-05-07

    Heat Assisted Magnetic Recording (HAMR) is a promising technology for next generation hard disk drives with significantly increased data recording capacities. In HAMR, an optical near-field transducer (NFT) is used to concentrate laser energy on a magnetic recording medium to fulfill the heat assist function. The key components of a NFT are transducer material, cladding material, and adhesion material between the cladding and the transducer materials. Since transducer materials and cladding materials have been widely reported, this paper focuses on the adhesion materials between the Au transducer and the Al{sub 2}O{sub 3} cladding material. A comparative study for two kinds of adhesion material, Ta and Cr, has been conducted. We found that Ta provides better thermal stability to the whole transducer than Cr. This is because after thermal annealing, chromium forms oxide material at interfaces and chromium atoms diffuse remarkably into the Au layer and react with Au to form Au alloy. This study also provides insights on the selection of adhesion material for HAMR transducer.

  15. Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Shuyu Lin

    2017-02-01

    Full Text Available The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

  16. Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers.

    Science.gov (United States)

    Lin, Shuyu; Xu, Jie

    2017-02-10

    The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

  17. Study of a Modified Displacement Transducer of a Piston in a Power Cylinder

    Directory of Open Access Journals (Sweden)

    S. C. BERA

    2011-05-01

    Full Text Available The position monitoring of the piston inside a power cylinder is very important in process plant measurement and control. In the present paper a modified inductance type position sensing technique of a power cylinder piston has been described. A modified inductance measuring transducer circuit has been designed to measure the change of inductance of a very high inductance coil. The theoretical equations of the proposed inductive sensor and the displacement transducer have been derived. The transducer has been experimentally tested and the experimental data are presented in the paper.

  18. Hysteretic self-oscillating bandpass current mode control for Class D audio amplifiers driving capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    A hysteretic self-oscillating bandpass current mode control (BPCM) scheme for Class D audio amplifiers driving capacitive transducers are presented. The scheme provides excellent stability margins and low distortion over a wide range of operating conditions. Small-signal behavior of the amplifier...... the rules of electrostatics have been known as very interesting alternatives to the traditional inefficient electrodynamic transducers. When driving capacitive transducers from a Class D audio amplifier the high impedance nature of the load represents a key challenge. The BPCM control scheme ensures a flat...

  19. Angle transducer based on fiber Bragg gratings able for tunnel auscultation

    Science.gov (United States)

    Quintela, A.; Lázaro, J. M.; Quintela, M. A.; Mirapeix, J.; Muñoz-Berti, V.; López-Higuera, J. M.

    2010-09-01

    In this paper an angle transducer based on Fiber Bragg Grating (FBG) is presented. Two gratings are glued to a metallic platen, one in each side. It is insensitive to temperature changes, given that the temperature shifts affect equally to both FBG. When the platen is uniformly bent an uniform strain appears in both sides of the platen. It depends on the bend angle and the platen length and thickness. The transducer has been designed to be used in the auscultation of tunnels during their construction process and during their live time. The transducer design and its characterization are presented.

  20. Influence of Ultrasonic Nonlinear Propagation on Hydrophone Calibration Using Two-Transducer Reciprocity Method

    Science.gov (United States)

    Yoshioka, Masahiro; Sato, Sojun; Kikuchi, Tsuneo; Matsuda, Yoichi

    2006-05-01

    In this study, the influence of ultrasonic nonlinear propagation on hydrophone calibration by the two-transducer reciprocity method is investigated quantitatively using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. It is proposed that the correction for the diffraction and attenuation of ultrasonic waves used in two-transducer reciprocity calibration can be derived using the KZK equation to remove the influence of nonlinear propagation. The validity of the correction is confirmed by comparing the sensitivities calibrated by the two-transducer reciprocity method and laser interferometry.