Efficient techniques for forced response involving linear modal components interconnected by discrete nonlinear connection elements

NASA Astrophysics Data System (ADS)

Avitabile, Peter; O'Callahan, John

2009-01-01

Generally, response analysis of systems containing discrete nonlinear connection elements such as typical mounting connections require the physical finite element system matrices to be used in a direct integration algorithm to compute the nonlinear response analysis solution. Due to the large size of these physical matrices, forced nonlinear response analysis requires significant computational resources. Usually, the individual components of the system are analyzed and tested as separate components and their individual behavior may essentially be linear when compared to the total assembled system. However, the joining of these linear subsystems using highly nonlinear connection elements causes the entire system to become nonlinear. It would be advantageous if these linear modal subsystems could be utilized in the forced nonlinear response analysis since much effort has usually been expended in fine tuning and adjusting the analytical models to reflect the tested subsystem configuration. Several more efficient techniques have been developed to address this class of problem. Three of these techniques given as: equivalent reduced model technique (ERMT);modal modification response technique (MMRT); andcomponent element method (CEM); are presented in this paper and are compared to traditional methods.

Molecular manipulations for enhancing luminescent bioreporters performance in the detection of toxic chemicals.

PubMed

Yagur-Kroll, Sharon; Belkin, Shimshon

2014-01-01

Microbial whole-cell bioreporters are genetically modified microorganisms that produce a quantifiable output in response to the presence of toxic chemicals or other stress factors. These bioreporters harbor a genetic fusion between a sensing element (usually a gene regulatory element responsive to the target) and a reporter element, the product of which may be quantitatively monitored either by its presence or by its activity. In this chapter we review genetic manipulations undertaken in order to improve bioluminescent bioreporter performance by increasing luminescent output, lowering the limit of detection, and shortening the response time. We describe molecular manipulations applied to all aspects of whole-cell bioreporters: the host strain, the expression system, the sensing element, and the reporter element. The molecular construction of whole-cell luminescent bioreporters, harboring fusions of gene promoter elements to reporter genes, has been around for over three decades; in most cases, these two genetic elements are combined "as is." This chapter outlines diverse molecular manipulations for enhancing the performance of such sensors.

Differential Regulation of Native Estrogen Receptor-Regulatory Elements by Estradiol, Tamoxifen, and Raloxifene

PubMed Central

Levy, Nitzan; Tatomer, Dierdre; Herber, Candice B.; Zhao, Xiaoyue; Tang, Hui; Sargeant, Toby; Ball, Lonnele J.; Summers, Jonathan; Speed, Terence P.; Leitman, Dale C.

2008-01-01

Estrogen receptors (ERs) regulate gene transcription by interacting with regulatory elements. Most information regarding how ER activates genes has come from studies using a small set of target genes or simple consensus sequences such as estrogen response element, activator protein 1, and Sp1 elements. However, these elements cannot explain the differences in gene regulation patterns and clinical effects observed with estradiol (E2) and selective estrogen receptor modulators. To obtain a greater understanding of how E2 and selective estrogen receptor modulators differentially regulate genes, it is necessary to investigate their action on a more comprehensive set of native regulatory elements derived from ER target genes. Here we used chromatin immunoprecipitation-cloning and sequencing to isolate 173 regulatory elements associated with ERα. Most elements were found in the introns (38%) and regions greater than 10 kb upstream of the transcription initiation site (38%); 24% of the elements were found in the proximal promoter region (<10 kb). Only 11% of the elements contained a classical estrogen response element; 23% of the elements did not have any known response elements, including one derived from the naked cuticle homolog gene, which was associated with the recruitment of p160 coactivators. Transfection studies found that 80% of the 173 elements were regulated by E2, raloxifene, or tamoxifen with ERα or ERβ. Tamoxifen was more effective than raloxifene at activating the elements with ERα, whereas raloxifene was superior with ERβ. Our findings demonstrate that E2, tamoxifen, and raloxifene differentially regulate native ER-regulatory elements isolated by chromatin immunoprecipitation with ERα and ERβ. PMID:17962382

A nuclear factor I-like activity and a liver-specific repressor govern estrogen-regulated in vitro transcription from the Xenopus laevis vitellogenin B1 promoter.

PubMed

Corthésy, B; Cardinaux, J R; Claret, F X; Wahli, W

1989-12-01

A hormone-controlled in vitro transcription system derived from Xenopus liver nuclear extracts was exploited to identify novel cis-acting elements within the vitellogenin gene B1 promoter region. In addition to the already well-documented estrogen-responsive element (ERE), two elements were found within the 140 base pairs upstream of the transcription initiation site. One of them, a negative regulatory element, is responsible for the lack of promoter activity in the absence of the hormone and, as demonstrated by DNA-binding assays, interacts with a liver-specific transcription factor. The second is required in association with the estrogen-responsive element to mediate hormonal induction and is recognized by the Xenopus liver homolog of nuclear factor I.

Sex change strategy and the aromatase genes.

PubMed

Gardner, L; Anderson, T; Place, A R; Dixon, B; Elizur, A

2005-04-01

Sequential hermaphroditism is a common reproductive strategy in many teleosts. Steroid production is known to mediate both the natural and induced sex change, yet beyond this the physiology directing this process has received little attention. Cytochrome P450 aromatase is a key enzyme in the hormonal pathway catalysing the conversion of sex steroids, androgens to oestrogens, and thus is highly relevant to the process of sex change. This study reports the isolation of cDNA sequences for aromatase isoforms CYP19A1 and CYP19A2 from teleost species representing three forms of sexual hermaphroditism: Lates calcarifer (protandry), Cromileptes altivelis (protogyny), and Gobiodon histrio (bi-directional). Deduced amino acid analysis of these isoforms with other reported isoforms from gonochoristic (single sex) teleosts revealed 56-95% identity within the same isoform while only 48-65% identity between isoforms irrespective of species and sexual strategy. Phylogenetic analysis supported this result separating sequences into isoform exclusive clades in spite of species apparent evolutionary distance. Furthermore, this study isolates 5' flanking regions of all above genes and describes putative cis-acting elements therein. Elements identified include steroidogenic factor 1 binding site (SF-1), oestrogen response element (ERE), progesterone response element (PRE), androgen response element (ARE), glucocorticoid response elements (GRE), peroxisome proliferator-activated receptor alpha/retinoid X receptor alpha heterodimer responsive element (PPARalpha/RXRalpha), nuclear factor kappabeta (NF-kappabeta), SOX 5, SOX 9, and Wilms tumor suppressor (WTI). A hypothetical in vivo model was constructed for both isoforms highlighting potential roles of these putative cis-acting elements with reference to normal function and sexual hermaphroditism.

Cis-regulatory element based targeted gene finding: genome-wide identification of abscisic acid- and abiotic stress-responsive genes in Arabidopsis thaliana.

PubMed

Zhang, Weixiong; Ruan, Jianhua; Ho, Tuan-Hua David; You, Youngsook; Yu, Taotao; Quatrano, Ralph S

2005-07-15

A fundamental problem of computational genomics is identifying the genes that respond to certain endogenous cues and environmental stimuli. This problem can be referred to as targeted gene finding. Since gene regulation is mainly determined by the binding of transcription factors and cis-regulatory DNA sequences, most existing gene annotation methods, which exploit the conservation of open reading frames, are not effective in finding target genes. A viable approach to targeted gene finding is to exploit the cis-regulatory elements that are known to be responsible for the transcription of target genes. Given such cis-elements, putative target genes whose promoters contain the elements can be identified. As a case study, we apply the above approach to predict the genes in model plant Arabidopsis thaliana which are inducible by a phytohormone, abscisic acid (ABA), and abiotic stress, such as drought, cold and salinity. We first construct and analyze two ABA specific cis-elements, ABA-responsive element (ABRE) and its coupling element (CE), in A.thaliana, based on their conservation in rice and other cereal plants. We then use the ABRE-CE module to identify putative ABA-responsive genes in A.thaliana. Based on RT-PCR verification and the results from literature, this method has an accuracy rate of 67.5% for the top 40 predictions. The cis-element based targeted gene finding approach is expected to be widely applicable since a large number of cis-elements in many species are available.

Finite element modelling to assess the effect of surface mounted piezoelectric patch size on vibration response of a hybrid beam

NASA Astrophysics Data System (ADS)

Rahman, N.; Alam, M. N.

2018-02-01

Vibration response analysis of a hybrid beam with surface mounted patch piezoelectric layer is presented in this work. A one dimensional finite element (1D-FE) model based on efficient layerwise (zigzag) theory is used for the analysis. The beam element has eight mechanical and a variable number of electrical degrees of freedom. The beams are also modelled in 2D-FE (ABAQUS) using a plane stress piezoelectric quadrilateral element for piezo layers and a plane stress quadrilateral element for the elastic layers of hybrid beams. Results are presented to assess the effect of size of piezoelectric patch layer on the free and forced vibration responses of thin and moderately thick beams under clamped-free and clamped-clamped configurations. The beams are subjected to unit step loading and harmonic loading to obtain the forced vibration responses. The vibration control using in phase actuation potential on piezoelectric patches is also studied. The 1D-FE results are compared with the 2D-FE results.

Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan Parasite Theileria parva▿

PubMed Central

Graham, Simon P.; Pellé, Roger; Yamage, Mat; Mwangi, Duncan M.; Honda, Yoshikazu; Mwakubambanya, Ramadhan S.; de Villiers, Etienne P.; Abuya, Evelyne; Awino, Elias; Gachanja, James; Mbwika, Ferdinand; Muthiani, Anthony M.; Muriuki, Cecelia; Nyanjui, John K.; Onono, Fredrick O.; Osaso, Julius; Riitho, Victor; Saya, Rosemary M.; Ellis, Shirley A.; McKeever, Declan J.; MacHugh, Niall D.; Gilbert, Sarah C.; Audonnet, Jean-Christophe; Morrison, W. Ivan; van der Bruggen, Pierre; Taracha, Evans L. N.

2008-01-01

Immunity against the bovine intracellular protozoan parasite Theileria parva has been shown to be mediated by CD8 T cells. Six antigens targeted by CD8 T cells from T. parva-immune cattle of different major histocompatibility complex (MHC) genotypes have been identified, raising the prospect of developing a subunit vaccine. To facilitate further dissection of the specificity of protective CD8 T-cell responses and to assist in the assessment of responses to vaccination, we set out to identify the epitopes recognized in these T. parva antigens and their MHC restriction elements. Nine epitopes in six T. parva antigens, together with their respective MHC restriction elements, were successfully identified. Five of the cytotoxic-T-lymphocyte epitopes were found to be restricted by products of previously described alleles, and four were restricted by four novel restriction elements. Analyses of CD8 T-cell responses to five of the epitopes in groups of cattle carrying the defined restriction elements and immunized with live parasites demonstrated that, with one exception, the epitopes were consistently recognized by animals of the respective genotypes. The analysis of responses was extended to animals immunized with multiple antigens delivered in separate vaccine constructs. Specific CD8 T-cell responses were detected in 19 of 24 immunized cattle. All responder cattle mounted responses specific for antigens for which they carried an identified restriction element. By contrast, only 8 of 19 responder cattle displayed a response to antigens for which they did not carry an identified restriction element. These data demonstrate that the identified antigens are inherently dominant in animals with the corresponding MHC genotypes. PMID:18070892

An Optimization-Based Approach to Injector Element Design

NASA Technical Reports Server (NTRS)

Tucker, P. Kevin; Shyy, Wei; Vaidyanathan, Rajkumar; Turner, Jim (Technical Monitor)

2000-01-01

An injector optimization methodology, method i, is used to investigate optimal design points for gaseous oxygen/gaseous hydrogen (GO2/GH2) injector elements. A swirl coaxial element and an unlike impinging element (a fuel-oxidizer-fuel triplet) are used to facilitate the study. The elements are optimized in terms of design variables such as fuel pressure drop, APf, oxidizer pressure drop, deltaP(sub f), combustor length, L(sub comb), and full cone swirl angle, theta, (for the swirl element) or impingement half-angle, alpha, (for the impinging element) at a given mixture ratio and chamber pressure. Dependent variables such as energy release efficiency, ERE, wall heat flux, Q(sub w), injector heat flux, Q(sub inj), relative combustor weight, W(sub rel), and relative injector cost, C(sub rel), are calculated and then correlated with the design variables. An empirical design methodology is used to generate these responses for both element types. Method i is then used to generate response surfaces for each dependent variable for both types of elements. Desirability functions based on dependent variable constraints are created and used to facilitate development of composite response surfaces representing the five dependent variables in terms of the input variables. Three examples illustrating the utility and flexibility of method i are discussed in detail for each element type. First, joint response surfaces are constructed by sequentially adding dependent variables. Optimum designs are identified after addition of each variable and the effect each variable has on the element design is illustrated. This stepwise demonstration also highlights the importance of including variables such as weight and cost early in the design process. Secondly, using the composite response surface that includes all five dependent variables, unequal weights are assigned to emphasize certain variables relative to others. Here, method i is used to enable objective trade studies on design issues such as component life and thrust to weight ratio. Finally, combining results from both elements to simulate a trade study, thrust-to-weight trends are illustrated and examined in detail.

77 FR 69827 - Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) or Superfund...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-21

.... G. Demonstrating the Four Elements As part of the annual work plan negotiation process, states or... eligibility for funding, use of funding, grant mechanisms and process for awarding funding, the allocation... elements of an environmental response program and that the response program establishes and maintains a...

Investigation of the applicability of using the triple redundant hydrogen sensor for methane sensing

NASA Technical Reports Server (NTRS)

Lantz, J. B.; Wynveen, R. A.

1983-01-01

Application specifications for the methane sensor were assembled and design guidelines, development goals and evaluation criteria were formulated. This was done to provide a framework to evaluate sensor performance and any design adjustments to the preprototype sensor that could be required to provide methane sensitivity. Good response to hydrogen was experimentally established for four hydrogen sensor elements to be later evaluated for methane response. Prior results were assembled and analyzed for other prototype hydrogen sensor performance parameters to form a comparison base. The four sensor elements previously shown to have good hydrogen response were experimentally evaluated for methane response in 2.5% methane-in-air. No response was obtained for any of the elements, despite the high methane concentration used (50% of the Lower Flammability Limit). It was concluded that the preprototype sensing elements were insensitive to methane and were hydrogen specific. Alternative sensor operating conditions and hardware design changes were considered to provide methane sensitivity to the preprototype sensor, including a variety of different methane sensing techniques. Minor changes to the existing sensor elements, sensor geometry and operating conditions will not make the preprototype hydrogen sensor respond to methane. New sensor elements that will provide methane and hydrogen sensitivity require replacement of the existing thermistor type elements. Some hydrogen sensing characteristics of the modified sensor will be compromised (larger in situ calibration gas volume and H2 nonspecificity). The preprototype hydrogen sensor should be retained for hydrogen monitoring and a separate methane sensor should be developed.

TECHNICAL NOTE: Direct finite-element analysis of the frequency response of a Y-Z lithium niobate SAW filter

NASA Astrophysics Data System (ADS)

Xu, Guanshui

2000-12-01

A direct finite-element model is developed for the full-scale analysis of the electromechanical phenomena involved in surface acoustic wave (SAW) devices. The equations of wave propagation in piezoelectric materials are discretized using the Galerkin method, in which an implicit algorithm of the Newmark family with unconditional stability is implemented. The Rayleigh damping coefficients are included in the elements near the boundary to reduce the influence of the reflection of waves. The performance of the model is demonstrated by the analysis of the frequency response of a Y-Z lithium niobate filter with two uniform ports, with emphasis on the influence of the number of electrodes. The frequency response of the filter is obtained through the Fourier transform of the impulse response, which is solved directly from the finite-element simulation. It shows that the finite-element results are in good agreement with the characteristic frequency response of the filter predicted by the simple phase-matching argument. The ability of the method to evaluate the influence of the bulk waves at the high-frequency end of the filter passband and the influence of the number of electrodes on insertion loss is noteworthy. We conclude that the direct finite-element analysis of SAW devices can be used as an effective tool for the design of high-performance SAW devices. Some practical computational challenges of finite-element modeling of SAW devices are discussed.

Translation-coupling systems

DOEpatents

Pfleger, Brian; Mendez-Perez, Daniel

2013-11-05

Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

Translation-coupling systems

DOEpatents

Pfleger, Brian; Mendez-Perez, Daniel

2015-05-19

Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

Mechanisms of extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway in depressive disorder☆

PubMed Central

Wang, Hongyan; Zhang, Yingquan; Qiao, Mingqi

2013-01-01

The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway plays an important role in the mechanism of action of antidepressant drugs and has dominated recent studies on the pathogenesis of depression. In the present review we summarize the known roles of extracellular signal-regulated kinase, cAMP response element-binding protein and brain-derived neurotrophic factor in the pathogenesis of depression and in the mechanism of action of antidepressant medicines. The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor pathway has potential to be used as a biological index to help diagnose depression, and as such it is considered as an important new target in the treatment of depression. PMID:25206732

Ternary Complex Factors and Cofactors Are Essential for Human T-Cell Leukemia Virus Type 1 Tax Transactivation of the Serum Response Element

PubMed Central

Shuh, Maureen; Derse, David

2000-01-01

The human T-cell leukemia virus type 1 Tax protein activates the expression of cellular immediate early genes controlled by the serum response element (SRE), which contains both the serum response factor (SRF) binding element (CArG box) and the ternary complex factor (TCF) binding element (Ets box). We show that TCF binding is necessary for Tax activation of the SRE and that Tax directly interacts with TCFs in vitro. In addition, Tax interactions with CREB binding protein (CBP) and p300- and CBP-associated factor were found to be essential for Tax activation of SRF-mediated transcription. PMID:11070040

IMS Infrasound Monitoring Test Site at Trafelberg, Austria: Preliminary Results from In-Situ Response Measurements of Infrasound Elements

DTIC Science & Technology

2010-09-01

IMS INFRASOUND MONITORING TEST SITE AT TRAFELBERG, AUSTRIA: PRELIMINARY RESULTS FROM IN-SITU RESPONSE MEASUREMENTS OF INFRASOUND ELEMENTS Thomas...The International Monitoring System (IMS) of the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO) has a unique infrasound test site...all four infrasound elements at I99 were made from 0.008 Hz to several Hz. For all four elements, from 0.01 to 0.1 Hz, the measured magnitude and

The genomic view of genes responsive to the antagonistic phytohormones, abscisic acid, and gibberellin.

PubMed

Yazaki, Junshi; Kikuchi, Shoshi

2005-01-01

We now have the various genomics tools for monocot (Oryza sativa) and a dicot (Arabidopsis thaliana) plant. Plant is not only a very important agricultural resource but also a model organism for biological research. It is important that the interaction between ABA and GA is investigated for controlling the transition from embryogenesis to germination in seeds using genomics tools. These studies have investigated the relationship between dormancy and germination using genomics tools. Genomics tools identified genes that had never before been annotated as ABA- or GA-responsive genes in plant, detected new interactions between genes responsive to the two hormones, comprehensively characterized cis-elements of hormone-responsive genes, and characterized cis-elements of rice and Arabidopsis. In these research, ABA- and GA-regulated genes have been classified as functional proteins (proteins that probably function in stress or PR tolerance) and regulatory proteins (protein factors involved in further regulation of signal transduction). Comparison between ABA and/or GA-responsive genes in rice and those in Arabidopsis has shown that the cis-element has specificity in each species. cis-Elements for the dehydration-stress response have been specified in Arabidopsis but not in rice. cis-Elements for protein storage are remarkably richer in the upstream regions of the rice gene than in those of Arabidopsis.

33 CFR Appendix D to Part 154 - Training Elements for Oil Spill Response Plans

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Training Elements for Oil Spill... Appendix D to Part 154—Training Elements for Oil Spill Response Plans 1. General 1.1The portion of the plan... contracted oil spill removal organizations and the procedures to notify the activate such organizations. 2.2...

33 CFR Appendix D to Part 154 - Training Elements for Oil Spill Response Plans

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Training Elements for Oil Spill... Appendix D to Part 154—Training Elements for Oil Spill Response Plans 1. General 1.1The portion of the plan... contracted oil spill removal organizations and the procedures to notify the activate such organizations. 2.2...

33 CFR Appendix D to Part 154 - Training Elements for Oil Spill Response Plans

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Training Elements for Oil Spill... Appendix D to Part 154—Training Elements for Oil Spill Response Plans 1. General 1.1The portion of the plan... contracted oil spill removal organizations and the procedures to notify the activate such organizations. 2.2...

33 CFR Appendix D to Part 154 - Training Elements for Oil Spill Response Plans

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Training Elements for Oil Spill... Appendix D to Part 154—Training Elements for Oil Spill Response Plans 1. General 1.1The portion of the plan... contracted oil spill removal organizations and the procedures to notify the activate such organizations. 2.2...

Isolation, characterization and expression analysis of the BABY BOOM (BBM) gene from Larix kaempferi × L. olgensis during adventitious rooting.

PubMed

Li, Kui-Peng; Sun, Xiao-Mei; Han, Hua; Zhang, Shou-Gong

2014-11-10

The full-length cDNA and genomic sequences of the BABY BOOM (BBM) gene, designated LkBBM, were isolated from Larix kaempferi × Larix olgensis. The 3324 bp cDNA was cloned and its open reading frame (ORF) consists of 2370 nucleotides. The deduced 789 amino acid protein contains two AP2 domains and a BBM specific motif. Four conserved motifs between BBM and PLT were identified, which may be conducive to the similar function of BBM and PLT. The three dimensional (3D) structure of LkBBM was predicted and β-sheets in the AP2-R2 domain of LkBBM might recognize the specific base pairs in the major groove. Analysis of the LkBBM gene structure indicates that the gene has eight introns and nine exons. In the 5'-flanking promoter region of LkBBM, many important potential cis-acting elements were identified, such as the TATABOX5 element (a functional TATA element), ROOTMOTIFTAPOX1 element (element of root specificity), AUXREPSIAA4 element (element involved in auxin responsiveness and gene expression in root meristem), MYB1AT element (element involved in MYB recognition), ARR1AT element (element involved in cytokinin responsiveness), GARE1OSREP1 element (element involved in gibberellin responsiveness) and PYRIMIDINEBOXHVEPB1 element (element involved in abscisic acid responsiveness), which all suggested that the expression of LkBBM is highly regulated. Compared with gene expression levels in the stem, stem tip and leaf, LkBBM shows a specific expression in the root, which indicates that LkBBM plays a key role in regulating the development and growth of root in larch. In the processing of larch adventitious root formation, LkBBM started to express on the eighth day after rooting treatment and its transcript level increased continuously afterwards. According to the gene characteristics, LkBBM is proposed as a molecular marker for root primordia of larch, and the initial period of LkBBM expression may be the formation period of root primordia in the processing of adventitious rooting of larch. Copyright © 2014 Elsevier B.V. All rights reserved.

Identification of unique cis-element pattern on simulated microgravity treated Arabidopsis by in silico and gene expression

NASA Astrophysics Data System (ADS)

Soh, Hyuncheol; Choi, Yongsang; Lee, Taek-Kyun; Yeo, Up-Dong; Han, Kyeongsik; Auh, Chungkyun; Lee, Sukchan

2012-08-01

Arabidopsis gene expression microarray (44 K) was used to detect genes highly induced under simulated microgravity stress (SMS). Ten SMS-inducible genes were selected from the microarray data and these 10 genes were found to be abundantly expressed in 3-week-old plants. Nine out of the 10 SMS-inducible genes were also expressed in response to the three abiotic stresses of drought, touch, and wounding in 3-week-old Arabidopsis plants respectively. However, WRKY46 was elevated only in response to SMS. Six other WRKY genes did not respond to SMS. To clarify the characteristics of the genes expressed at high levels in response to SMS, 20 cis-elements in the promoters of the 40 selected genes including the 10 SMS-inducible genes, the 6 WRKY genes, and abiotic stress-inducible genes were analyzed and their spatial positions on each promoter were determined. Four cis-elements (M/T-G-T-P from MYB1AT or TATABOX5, GT1CONSENSUS, TATABOX5, and POLASIG1) showed a unique spatial arrangement in most SMS-inducible genes including WRKY46. Therefore the M/T-G-T-P cis-element patterns identified in the promoter of WRKY46 may play important roles in regulating gene expression in response to SMS. The presences of the cis-element patterns suggest that the order or spatial positioning of certain groups of cis-elements is more important than the existence or numbers of specific cis-elements. Taken together, our data indicate that WRKY46 is a novel SMS inducible transcription factor and the unique spatial arrangement of cis-elements shown in WRKY46 promoter may play an important role for its response to SMS.

The Yeast Anaerobic Response Element AR1b Regulates Aerobic Antifungal Drug-dependent Sterol Gene Expression*

PubMed Central

Gallo-Ebert, Christina; Donigan, Melissa; Liu, Hsing-Yin; Pascual, Florencia; Manners, Melissa; Pandya, Devanshi; Swanson, Robert; Gallagher, Denise; Chen, WeiWei; Carman, George M.; Nickels, Joseph T.

2013-01-01

Saccharomyces cerevisiae ergosterol biosynthesis, like cholesterol biosynthesis in mammals, is regulated at the transcriptional level by a sterol feedback mechanism. Yeast studies defined a 7-bp consensus sterol-response element (SRE) common to genes involved in sterol biosynthesis and two transcription factors, Upc2 and Ecm22, which direct transcription of sterol biosynthetic genes. The 7-bp consensus SRE is identical to the anaerobic response element, AR1c. Data indicate that Upc2 and Ecm22 function through binding to this SRE site. We now show that it is two novel anaerobic AR1b elements in the UPC2 promoter that direct global ERG gene expression in response to a block in de novo ergosterol biosynthesis, brought about by antifungal drug treatment. The AR1b elements are absolutely required for auto-induction of UPC2 gene expression and protein and require Upc2 and Ecm22 for function. We further demonstrate the direct binding of recombinant expressed S. cerevisiae ScUpc2 and pathogenic Candida albicans CaUpc2 and Candida glabrata CgUpc2 to AR1b and SRE/AR1c elements. Recombinant endogenous promoter studies show that the UPC2 anaerobic AR1b elements act in trans to regulate ergosterol gene expression. Our results indicate that Upc2 must occupy UPC2 AR1b elements in order for ERG gene expression induction to take place. Thus, the two UPC2-AR1b elements drive expression of all ERG genes necessary for maintaining normal antifungal susceptibility, as wild type cells lacking these elements have increased susceptibility to azole antifungal drugs. Therefore, targeting these specific sites for antifungal therapy represents a novel approach to treat systemic fungal infections. PMID:24163365

Diffractive micro-optical element with nonpoint response

NASA Astrophysics Data System (ADS)

Soifer, Victor A.; Golub, Michael A.

1993-01-01

Common-use diffractive lenses have microrelief zones in the form of simple rings that provide only an optical power but do not contain any image information. They have a point-image response under point-source illumination. We must use a more complicated non-point response to focus a light beam into different light marks, letter-type images as well as for optical pattern recognition. The current presentation describes computer generation of diffractive micro- optical elements with complicated curvilinear zones of a regular piecewise-smooth structure and grey-level or staircase phase microrelief. The manufacture of non-point response elements uses the steps of phase-transfer calculation and orthogonal-scan masks generation or lithographic glass etching. Ray-tracing method is shown to be applicable in this task. Several working samples of focusing optical elements generated by computer and photolithography are presented. Using the experimental results we discuss here such applications as laser branding.

The pioneer projects: Economical exploration of the solar system

NASA Technical Reports Server (NTRS)

Spahr, J. R.; Hall, C. F.

1975-01-01

The interplanetary Pioneer missions are reviewed in terms of management implications and cost control. The responsibilities, organizational structure, and management practices of the Pioneer Projects are presented. The lines of authority and areas of responsibility of the principal organizational elements supporting the Pioneer missions are identified, and the methods employed for maintaining effective and timely interactions among these elements are indicated. The technical and administrative functions of the various organizational elements of the Pioneer Project Office at Ames Research Center are described in terms of their management responsibilities and interactions with other elements of the Project Office and with external organizations having Pioneer Project responsibilities. The management and control of activities prior to and during the hardware procurement phase are described to indicate the basis for obtaining visibility of the technical progress, utilization of resources, and cost performance of the contractors and other institutions supporting the Pioneer projects.

Shock load analysis of rotor for rolling element bearings and gas foil bearings: A comparative study

NASA Astrophysics Data System (ADS)

Bhore, Skylab Paulas

2018-04-01

In this paper, a comparative study on the shock load analysis of rotor supported by rolling element bearings and gas foil journal bearings is presented. The rotor bearing system is modeled using finite element method. Timoshenko beam element with 4 degree of freedom at each node is used. The shock load is represented by half sine pulse and applied to the base of the rotor bearing system. The stiffness and damping coefficient of the bearings are incorporated in the model. The generalized equation of motion of rotor bearing system is solved by Newmark beta method and responses of rotor at bearing position are predicted. It is observed that the responses are sensitive to the direction of applied excitation and its magnitude and pulse duration. The amplitude of responses of rotor supported on gas foil bearings are significantly less than that of rolling element bearings.

Frequency response function (FRF) based updating of a laser spot welded structure

NASA Astrophysics Data System (ADS)

Zin, M. S. Mohd; Rani, M. N. Abdul; Yunus, M. A.; Sani, M. S. M.; Wan Iskandar Mirza, W. I. I.; Mat Isa, A. A.

2018-04-01

The objective of this paper is to present frequency response function (FRF) based updating as a method for matching the finite element (FE) model of a laser spot welded structure with a physical test structure. The FE model of the welded structure was developed using CQUAD4 and CWELD element connectors, and NASTRAN was used to calculate the natural frequencies, mode shapes and FRF. Minimization of the discrepancies between the finite element and experimental FRFs was carried out using the exceptional numerical capability of NASTRAN Sol 200. The experimental work was performed under free-free boundary conditions using LMS SCADAS. Avast improvement in the finite element FRF was achieved using the frequency response function (FRF) based updating with two different objective functions proposed.

Estrogen-dependent downregulation of hairy and enhancer of split homolog-1 gene expression in breast cancer cells is mediated via a 3' distal element.

PubMed

Müller, Patrick; Merrell, Kenneth W; Crofts, Justin D; Rönnlund, Caroline; Lin, Chin-Yo; Gustafsson, Jan-Ake; Ström, Anders

2009-03-01

Regulation of hairy and enhancer of split homologue-1 (HES-1) by estradiol and all-trans retinoic acid affects proliferation of human breast cancer cells. Here, we identify and characterize cis-regulatory elements involved in HES-1 regulation. In the distal 5' promoter of the HES-1 gene, we found a retinoic acid response element and in the distal 3' region, an estrogen receptor alpha(ER)alpha binding site. The ERalpha binding site, composed of an estrogen response element (ERE) and an ERE half-site, is important for both ERalpha binding and transcriptional regulation. Chromatin immunoprecipitation assays revealed that ERalpha is recruited to the ERE and associates with the HES-1 promoter. We also show recruitment of nuclear receptor co-regulators to the ERE in response to estradiol, followed by a decrease in histone acetylation and RNA polymerase II docking in the HES-1 promoter region. Our findings are consistent with a novel type of repressive estrogen response element in the distal 3' region of the HES-1 gene.

Remission of Diabetes by Insulin Gene Therapy Using a Hepatocyte-specific and Glucose-responsive Synthetic Promoter

PubMed Central

Han, Jaeseok; McLane, Brienne; Kim, Eung-Hwi; Yoon, Ji-Won; Jun, Hee-Sook

2011-01-01

Efficient production of insulin in response to changes in glucose levels has been a major issue for insulin gene therapy to treat diabetes. To express target genes in response to glucose specifically in hepatocytes, we generated a synthetic promoter library containing hepatocyte nuclear factor-1, CAAT/enhancer-binding protein (C/EBP) response element, and glucose-response element. Combinations of these three cis-elements in 3-, 6-, or 9-element configurations were screened for transcriptional activity and then glucose responsiveness in vitro. The most effective promoter (SP23137) was selected for further study. Intravenous administration of a recombinant adenovirus expressing furin-cleavable rat insulin under control of the SP23137 promoter into streptozotocin (STZ)-induced diabetic mice resulted in normoglycemia, which was maintained for >30 days. Glucose tolerance tests showed that treated mice produced insulin in response to glucose and cleared exogenous glucose from the blood in a manner similar to nondiabetic control mice, although the clearance was somewhat delayed. Insulin expression was seen specifically in the liver and not in other organs. These observations indicate the potential of this synthetic, artificial promoter to regulate glucose-responsive insulin production and remit hyperglycemia, thus providing a new method of liver-directed insulin gene therapy for type 1 diabetes. PMID:21119621

Remission of diabetes by insulin gene therapy using a hepatocyte-specific and glucose-responsive synthetic promoter.

PubMed

Han, Jaeseok; McLane, Brienne; Kim, Eung-Hwi; Yoon, Ji-Won; Jun, Hee-Sook

2011-03-01

Efficient production of insulin in response to changes in glucose levels has been a major issue for insulin gene therapy to treat diabetes. To express target genes in response to glucose specifically in hepatocytes, we generated a synthetic promoter library containing hepatocyte nuclear factor-1, CAAT/enhancer-binding protein (C/EBP) response element, and glucose-response element. Combinations of these three cis-elements in 3-, 6-, or 9-element configurations were screened for transcriptional activity and then glucose responsiveness in vitro. The most effective promoter (SP23137) was selected for further study. Intravenous administration of a recombinant adenovirus expressing furin-cleavable rat insulin under control of the SP23137 promoter into streptozotocin (STZ)-induced diabetic mice resulted in normoglycemia, which was maintained for >30 days. Glucose tolerance tests showed that treated mice produced insulin in response to glucose and cleared exogenous glucose from the blood in a manner similar to nondiabetic control mice, although the clearance was somewhat delayed. Insulin expression was seen specifically in the liver and not in other organs. These observations indicate the potential of this synthetic, artificial promoter to regulate glucose-responsive insulin production and remit hyperglycemia, thus providing a new method of liver-directed insulin gene therapy for type 1 diabetes.

Isolation and functional characterization of CE1 binding proteins.

PubMed

Lee, Sun-ji; Park, Ji Hye; Lee, Mi Hun; Yu, Ji-hyun; Kim, Soo Young

2010-12-16

Abscisic acid (ABA) is a plant hormone that controls seed germination, protective responses to various abiotic stresses and seed maturation. The ABA-dependent processes entail changes in gene expression. Numerous genes are regulated by ABA, and promoter analyses of the genes revealed that cis-elements sharing the ACGTGGC consensus sequence are ubiquitous among ABA-regulated gene promoters. The importance of the core sequence, which is generally known as ABA response element (ABRE), has been demonstrated by various experiments, and its cognate transcription factors known as ABFs/AREBs have been identified. Although necessary, ABRE alone is not sufficient, and another cis-element known as "coupling element (CE)" is required for full range ABA-regulation of gene expression. Several CEs are known. However, despite their importance, the cognate transcription factors mediating ABA response via CEs have not been reported to date. Here, we report the isolation of transcription factors that bind one of the coupling elements, CE1. To isolate CE1 binding proteins, we carried out yeast one-hybrid screens. Reporter genes containing a trimer of the CE1 element were prepared and introduced into a yeast strain. The yeast was transformed with library DNA that represents RNA isolated from ABA-treated Arabidopsis seedlings. From the screen of 3.6 million yeast transformants, we isolated 78 positive clones. Analysis of the clones revealed that a group of AP2/ERF domain proteins binds the CE1 element. We investigated their expression patterns and analyzed their overexpression lines to investigate the in vivo functions of the CE element binding factors (CEBFs). Here, we show that one of the CEBFs, AtERF13, confers ABA hypersensitivity in Arabidopsis, whereas two other CEBFs enhance sugar sensitivity. Our results indicate that a group of AP2/ERF superfamily proteins interacts with CE1. Several CEBFs are known to mediate defense or abiotic stress response, but the physiological functions of other CEBFs remain to be determined. Our in vivo functional analysis of several CEBFs suggests that they are likely to be involved in ABA and/or sugar response. Together with previous results reported by others, our current data raise an interesting possibility that the coupling element CE1 may function not only as an ABRE but also as an element mediating biotic and abiotic stress responses.

Implications of Responsive Space on the Flight Software Architecture

NASA Technical Reports Server (NTRS)

Wilmot, Jonathan

2006-01-01

The Responsive Space initiative has several implications for flight software that need to be addressed not only within the run-time element, but the development infrastructure and software life-cycle process elements as well. The runtime element must at a minimum support Plug & Play, while the development and process elements need to incorporate methods to quickly generate the needed documentation, code, tests, and all of the artifacts required of flight quality software. Very rapid response times go even further, and imply little or no new software development, requiring instead, using only predeveloped and certified software modules that can be integrated and tested through automated methods. These elements have typically been addressed individually with significant benefits, but it is when they are combined that they can have the greatest impact to Responsive Space. The Flight Software Branch at NASA's Goddard Space Flight Center has been developing the runtime, infrastructure and process elements needed for rapid integration with the Core Flight software System (CFS) architecture. The CFS architecture consists of three main components; the core Flight Executive (cFE), the component catalog, and the Integrated Development Environment (DE). This paper will discuss the design of the components, how they facilitate rapid integration, and lessons learned as the architecture is utilized for an upcoming spacecraft.

Long-Lasting Impairment of mGluR5-Activated Intracellular Pathways in the Striatum After Withdrawal of Cocaine Self-Administration

PubMed Central

Hoffmann, Hanne Mette; Crouzin, Nadine; Moreno, Estefanía; Raivio, Noora; Fuentes, Silvia; McCormick, Peter J.; Vignes, Michel

2017-01-01

Abstract Background: Cocaine addiction continues to be a major heath concern, and despite public health intervention there is a lack of efficient pharmacological treatment options. A newly identified potential target are the group I metabotropic glutamate receptors, with allosteric modulators showing particular promise. Methods: We evaluated the capacity of group I metabotropic glutamate receptors to induce functional responses in ex vivo striatal slices from rats with (1) acute cocaine self-administration, (2) chronic cocaine self-administration, and (3) 60 days cocaine self-administration withdrawal by Western blot and extracellular recordings of synaptic transmission. Results: We found that striatal group I metabotropic glutamate receptors are the principal mediator of the mGluR1/5 agonist (RS)-3,5-dihydroxyphenylglycine-induced cAMP responsive-element binding protein phosphorylation. Both acute and chronic cocaine self-administration blunted group I metabotropic glutamate receptor effects on cAMP responsive-element binding protein phosphorylation in the striatum, which correlated with the capacity to induce long-term depression, an effect that was maintained 60 days after chronic cocaine self-administration withdrawal. In the nucleus accumbens, the principal brain region mediating the rewarding effects of drugs, chronic cocaine self-administration blunted group I metabotropic glutamate receptor stimulation of extracellular signal-regulated protein kinases 1/2 and cAMP responsive-element binding protein. Interestingly, the group I metabotropic glutamate receptor antagonist/inverse-agonist, 2-methyl-6-(phenylethynyl)pyridine hydrochloride, led to a specific increase in cAMP responsive-element binding protein phosphorylation after chronic cocaine self-administration, specifically in the nucleus accumbens, but not in the striatum. Conclusions: Prolonged cocaine self-administration, through withdrawal, leads to a blunting of group I metabotropic glutamate receptor responses in the striatum. In addition, specifically in the accumbens, group I metabotropic glutamate receptor signaling to cAMP responsive-element binding protein shifts from an agonist-induced to an antagonist-induced cAMP responsive-element binding protein phosphorylation. PMID:27744406

Zac1, an Sp1-like protein, regulates human p21{sup WAF1/Cip1} gene expression in HeLa cells

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

Liu, Pei-Yao; Hsieh, Tsai-Yuan; Liu, Shu-Ting

2011-12-10

Zac1 functions as both a transcription factor and a transcriptional cofactor for p53, nuclear receptors (NRs) and NR coactivators. Zac1 might also act as a transcriptional repressor via the recruitment of histone deacetylase 1 (HDAC1). The ability of Zac1 to interact directly with GC-specific elements indicates that Zac1 possibly binds to Sp1-responsive elements. In the present study, our data show that Zac1 is able to interact directly with the Sp1-responsive element in the p21{sup WAF1/Cip1} gene promoter and enhance the transactivation activity of Sp1 through direct physical interaction. Our data further demonstrate that Zac1 might enhance Sp1-specific promoter activity bymore » interacting with the Sp1-responsive element, affecting the transactivation activity of Sp1 via a protein-protein interaction, or competing the HDAC1 protein away from the pre-existing Sp1/HDAC1 complex. Finally, the synergistic regulation of p21{sup WAF1/Cip1} gene expression by Zac1 and Sp1 is mediated by endogenous p53 protein and p53-responsive elements in HeLa cells. Our work suggests that Zac1 might serve as an Sp1-like protein that directly interacts with the Sp1-responsive element to oligomerize with and/or to coactivate Sp1.« less

Finite element analysis of notch behavior using a state variable constitutive equation

NASA Technical Reports Server (NTRS)

Dame, L. T.; Stouffer, D. C.; Abuelfoutouh, N.

1985-01-01

The state variable constitutive equation of Bodner and Partom was used to calculate the load-strain response of Inconel 718 at 649 C in the root of a notch. The constitutive equation was used with the Bodner-Partom evolution equation and with a second evolution equation that was derived from a potential function of the stress and state variable. Data used in determining constants for the constitutive models was from one-dimensional smooth bar tests. The response was calculated for a plane stress condition at the root of the notch with a finite element code using constant strain triangular elements. Results from both evolution equations compared favorably with the observed experimental response. The accuracy and efficiency of the finite element calculations also compared favorably to existing methods.

33 CFR Appendix D to Part 154 - Training Elements for Oil Spill Response Plans

Code of Federal Regulations, 2010 CFR

2010-07-01

... Response Plans D Appendix D to Part 154 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Pt. 154, App. D Appendix D to Part 154—Training Elements for Oil Spill Response Plans 1. General 1.1The portion of the plan...

Isolation of Persicaria minor sesquiterpene synthase promoter and its deletions for transgenic Arabidopsis thaliana

NASA Astrophysics Data System (ADS)

Omar, Aimi Farehah; Ismail, Ismanizan

2016-11-01

Sesquiterpene synthase (SS) catalyzes the formation of sesquiterpenes from farnesyl diphosphate (FDP) via carbocation intermediates. In this study, the promoter region of sesquiterpene synthase was isolated from Persicaria minor to identify possible cis-acting elements in the promoter. The full-length PmSS promoter of P. minor is 1824-bp sequences. The sequence was analyzed and several putative cis-acting regulatory elements were identified. Three cis-acting regulatory elements were selected for deletion analysis which are cis-acting element involved in wound responsiveness (WUN), cis - acting element involved in defense and stress responsiveness (TC) and cis-acting element involved in ABA responsiveness (ABRE). Series of deletions were conducted to assess the promoter activity producing three truncated fragments promoter; Prom 2 1606-bp, Prom 3 1144- bp, and Prom 4 921-bp. The full-length promoter and its deletion series were cloned into the pBGWFS7 vector which contain β-glucuronidase (GUS) gene and green fluorescent protein (GFP) as the reporter gene. All constructs were successfully transformed into Arabidopsis thaliana based on PCR of positive BASTA resistance plants.

Molecular analysis of UAS(E), a cis element containing stress response elements responsible for ethanol induction of the KlADH4 gene of Kluyveromyces lactis.

PubMed

Mazzoni, C; Santori, F; Saliola, M; Falcone, C

2000-01-01

KlADH4 is a gene of Kluyveromyces lactis encoding a mitochondrial alcohol dehydrogenase activity, which is specifically induced by ethanol and insensitive to glucose repression. In this work, we report the molecular analysis of UAS(E), an element of the KlADH4 promoter which is essential for the induction of KlADH4 in the presence of ethanol. UAS(E) contains five stress response elements (STREs), which have been found in many genes of Saccharomyces cerevisiae involved in the response of cells to conditions of stress. Whereas KlADH4 is not responsive to stress conditions, the STREs present in UAS(E) seem to play a key role in the induction of the gene by ethanol, a situation that has not been observed in the related yeast S. cerevisiae. Gel retardation experiments showed that STREs in the KlADH4 promoter can bind factor(s) under non-inducing conditions. Moreover, we observed that the RAP1 binding site present in UAS(E) binds KlRap1p.

Superconducting fault current-limiter with variable shunt impedance

DOEpatents

Llambes, Juan Carlos H; Xiong, Xuming

2013-11-19

A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

Response of basic structural elements and B-52 structural components to simulated nuclear overpressure. Volume II-program data (basic structural elements). Final report, 1 June 1977-30 September 1979

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

Syring, R.P.; Grubb, R.L.

1979-09-30

This document reports on the following: (1) experimental determination of the response of 16 basic structural elements and 7 B-52 components to simulated nuclear overpressure environments (utilizing Sandia Corporation's Thunderpipe Shock Tube), (2) analysis of these test specimens utilizing the NOVA-2 computer program, and (3) correlation of test and analysis results.

Vitamin D receptor displays DNA binding and transactivation as a heterodimer with the retinoid X receptor, but not with the thyroid hormone receptor.

PubMed

Thompson, P D; Hsieh, J C; Whitfield, G K; Haussler, C A; Jurutka, P W; Galligan, M A; Tillman, J B; Spindler, S R; Haussler, M R

1999-12-01

The vitamin D receptor (VDR) is a transcription factor believed to function as a heterodimer with the retinoid X receptor (RXR). However, it was reported [Schräder et al., 1994] that, on putative vitamin D response elements (VDREs) within the rat 9k and mouse 28k calcium binding protein genes (rCaBP 9k and mCaBP 28k), VDR and thyroid hormone receptor (TR) form heterodimers that transactivate in response to both 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) and triiodothyronine (T(3)). We, therefore, examined associations of these receptors on the putative rCaBP 9k and mCaBP 28k VDREs, as well as on established VDREs from the rat osteocalcin (rOC) and mouse osteopontin (mOP) genes, plus the thyroid hormone response element (TRE) from the rat myosin heavy chain (rMHC) gene. In gel mobility shift assays, we found no evidence for VDR-TR heterodimer interaction with any tested element. Further, employing these hormone response elements linked to reporter genes in transfected cells, VDR and TR mediated responses to their cognate ligands only from the rOC/mOP and rMHC elements, respectively, while the CaBP elements were unresponsive to any combination of ligand(s). Utilizing the rOC and mOP VDREs, two distinct repressive actions of TR on VDR-mediated signaling were demonstrated: a T(3)-independent action, presumably via direct TR-RXR competition for DNA binding, and a T(3)-dependent repression, likely by diversion of limiting RXR from VDR-RXR toward the formation of TR-RXR heterodimers. The relative importance of these two mechanisms differed in a response element-specific manner. These results may provide a partial explanation for the observed association between hyperthyroidism and bone demineralization/osteoporosis. Copyright 1999 Wiley-Liss, Inc.

Hybrid Evidence Theory-based Finite Element/Statistical Energy Analysis method for mid-frequency analysis of built-up systems with epistemic uncertainties

NASA Astrophysics Data System (ADS)

Yin, Shengwen; Yu, Dejie; Yin, Hui; Lü, Hui; Xia, Baizhan

2017-09-01

Considering the epistemic uncertainties within the hybrid Finite Element/Statistical Energy Analysis (FE/SEA) model when it is used for the response analysis of built-up systems in the mid-frequency range, the hybrid Evidence Theory-based Finite Element/Statistical Energy Analysis (ETFE/SEA) model is established by introducing the evidence theory. Based on the hybrid ETFE/SEA model and the sub-interval perturbation technique, the hybrid Sub-interval Perturbation and Evidence Theory-based Finite Element/Statistical Energy Analysis (SIP-ETFE/SEA) approach is proposed. In the hybrid ETFE/SEA model, the uncertainty in the SEA subsystem is modeled by a non-parametric ensemble, while the uncertainty in the FE subsystem is described by the focal element and basic probability assignment (BPA), and dealt with evidence theory. Within the hybrid SIP-ETFE/SEA approach, the mid-frequency response of interest, such as the ensemble average of the energy response and the cross-spectrum response, is calculated analytically by using the conventional hybrid FE/SEA method. Inspired by the probability theory, the intervals of the mean value, variance and cumulative distribution are used to describe the distribution characteristics of mid-frequency responses of built-up systems with epistemic uncertainties. In order to alleviate the computational burdens for the extreme value analysis, the sub-interval perturbation technique based on the first-order Taylor series expansion is used in ETFE/SEA model to acquire the lower and upper bounds of the mid-frequency responses over each focal element. Three numerical examples are given to illustrate the feasibility and effectiveness of the proposed method.

Modeling 3D PCMI using the Extended Finite Element Method with higher order elements

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

Jiang, W.; Spencer, Benjamin W.

2017-03-31

This report documents the recent development to enable XFEM to work with higher order elements. It also demonstrates the application of higher order (quadratic) elements to both 2D and 3D models of PCMI problems, where discrete fractures in the fuel are represented using XFEM. The modeling results demonstrate the ability of the higher order XFEM to accurately capture the effects of a crack on the response in the vicinity of the intersecting surfaces of cracked fuel and cladding, as well as represent smooth responses in the regions away from the crack.

Characterization of an estrogen-responsive element implicated in regulation of the rainbow trout estrogen receptor gene.

PubMed

Le Dréan, Y; Lazennec, G; Kern, L; Saligaut, D; Pakdel, F; Valotaire, Y

1995-08-01

We previously reported that the expression of the rainbow trout estrogen receptor (rtER) gene is markedly increased by estradiol (E2). In this paper, we have used transient transfection assays with reporter plasmids expressing chloramphenicol acetyl transferase (CAT), linked to 5' flanking regions of the rtER gene promoter, to identify cis-elements responsible for E2 inducibility. Deletion analysis localized an estrogen-responsive element (ERE), at position +242, with one mutation on the first base compared with the consensus sequence. This element confers estrogen responsiveness to CAT reporter linked to both the herpes simplex virus thymidine kinase promoter and the homologous rtER promoter. Moreover, using a 0.2 kb fragment of the rtER promoter encompassing the ERE and the rtER DNA binding domain obtained from a bacterial expression system, DNase I footprinting experiments demonstrated a specific protection covering 20 bp (+240/+260) containing the ERE sequence. Based on these studies, we believe that this ERE sequence, identified in the rtER gene promoter, may be a major cis-acting element involved in the regulation of the gene by estrogen.

Layerwise Finite Elements for Smart Piezoceramic Composite Plates in Thermal Environments

NASA Technical Reports Server (NTRS)

Saravanos, Dimitris A.; Lee, Ho-Jun

1996-01-01

Analytical formulations are presented which account for the coupled mechanical, electrical, and thermal response of piezoelectric composite laminates and plate structures. A layerwise theory is formulated with the inherent capability to explicitly model the active and sensory response of piezoelectric composite plates having arbitrary laminate configurations in thermal environments. Finite element equations are derived and implemented for a bilinear 4-noded plate element. Application cases demonstrate the capability to manage thermally induced bending and twisting deformations in symmetric and antisymmetric composite plates with piezoelectric actuators, and show the corresponding electrical response of distributed piezoelectric sensors. Finally, the resultant stresses in the thermal piezoelectric composite laminates are investigated.

Functional Response of NiTi Elements for Smart Micro-actuation Applications

NASA Astrophysics Data System (ADS)

Biffi, C. A.; Nespoli, A.; Previtali, B.; Villa, E.; Tuissi, A.

2014-07-01

Shape memory alloys (SMAs) can be considered a good candidate for actuation applications in the current micro-technology field. In the micro-scale, the temporal response of the SMA actuators can be improved, because of faster cooling during the austenite-martensite transformation. One of the most investigated geometries for this purpose has been the snake-like arrangement, which allows high strokes with considerable forces to be obtained. In this work, SMA elements for micro-actuators were patterned by laser machining in a snake-like shape. Subsequent surface chemical etching was adopted to improve the functional properties of the micro-elements. Calorimetric analysis and thermo-mechanical response of 90 μm thick SMA elements were reported for the evaluation of their functional performances. Moreover, the effect of post-thermal treatment and grain orientation were also evaluated on the final performances.

Response of basic structural elements and B-52 structural components to simulated nuclear overpressure. Volume I-program description and results (basic structural elements). Final report, 1 June 1977-30 September 1979

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

Syring, R.P.; Grubb, R.L.

1979-09-30

This document reports on the following: (1) experimental determination of the response of 16 basic structural elements and 7 B-52 components to simulated nuclear overpressure environments (utilizing Sandia Corporation's Thunderpipe Shock Tube), (2) analysis of these test specimens utilizing the NOVA-2 computer program, and (3) correlation of test and analysis results.

Responses of trace elements to aerobic maximal exercise in elite sportsmen.

PubMed

Otag, Aynur; Hazar, Muhsin; Otag, Ilhan; Gürkan, Alper Cenk; Okan, Ilyas

2014-02-21

Trace elements are chemical elements needed in minute quantities for the proper growth, development, and physiology of the organism. In biochemistry, a trace element is also referred to as a micronutrient. Trace elements, such as nickel, cadmium, aluminum, silver, chromium, molybdenum, germanium, tin, titanium, tungsten, scandium, are found naturally in the environment and human exposure derives from a variety of sources, including air, drinking water and food. The Purpose of this study was investigated the effect of aerobic maximal intensity endurance exercise on serum trace elements as well-trained individuals of 28 wrestlers (age (year) 19.64±1.13, weight (Kg) 70.07 ± 15.69, height (cm) 176.97 ± 6.69) during and after a 2000 meter Ergometer test protocol was used to perform aerobic (75 %) maximal endurance exercise. Trace element serum levels were analyzed from blood samples taken before, immediately after and one hour after the exercise. While an increase was detected in Chromium (Cr), Nickel (Ni), Molybdenum (Mo) and Titanium (Ti) serum levels immediately after the exercise, a decrease was detected in Aluminum (Al), Scandium (Sc) and Tungsten (W) serum levels. Except for aluminum, the trace elements we worked on showed statistically meaningful responses (P < 0.05 and P < 0.001). According to the responses of trace elements to the exercise showed us the selection and application of the convenient sport is important not only in terms of sportsman performance but also in terms of future healthy life plans and clinically.

Development of a multi-element microdosimetric detector based on a thick gas electron multiplier

NASA Astrophysics Data System (ADS)

Anjomani, Z.; Hanu, A. R.; Prestwich, W. V.; Byun, S. H.

2017-03-01

A prototype multi-element gaseous microdosimetric detector was developed using the Thick Gas Electron Multiplier (THGEM) technique. The detector aims at measuring neutron and gamma-ray dose rates for weak neutron-gamma radiation fields. The multi-element design was employed to increase the neutron detection efficiency. The prototype THGEM multi-element detector consists of three layers of tissue equivalent plastic hexagons and each layer houses a hexagonal array of seven cylindrical gas cavity elements with equal heights and diameters of 17 mm. The final detector structure incorporates 21 gaseous volumes. Owing to the absence of wire electrodes, the THGEM multi-element detector offers flexible and convenient fabrication. The detector responses to neutron and gamma-ray were investigated using the McMaster Tandetron 7Li(p,n) neutron source. The dosimetric performance of the detector is presented in contrast to the response of a commercial tissue equivalent proportional counter. Compared to the standard TEPC response, the detector gave a consistent microdosimetric response with an average discrepancy of 8 % in measured neutron absorbed dose. An improvement of a factor of 3.0 in neutron detection efficiency has been accomplished with only a small degradation in energy resolution. However, its low energy cut off is about 6 keV/μm, which is not sufficient to measure the gamma-ray dose. This problem will be addressed by increasing the electron multiplication gain using double THGEM layers.

cDNA cloning, genomic organization and expression analysis during somatic embryogenesis of the translationally controlled tumor protein (TCTP) gene from Japanese larch (Larix leptolepis).

PubMed

Zhang, Li-Feng; Li, Wan-Feng; Han, Su-Ying; Yang, Wen-Hua; Qi, Li-Wang

2013-10-15

A full-length cDNA and genomic sequences of a translationally controlled tumor protein (TCTP) gene were isolated from Japanese larch (Larix leptolepis) and designated LaTCTP. The length of the cDNA was 1, 043 bp and contained a 504 bp open reading frame that encodes a predicted protein of 167 amino acids, characterized by two signature sequences of the TCTP protein family. Analysis of the LaTCTP gene structure indicated four introns and five exons, and it is the largest of all currently known TCTP genes in plants. The 5'-flanking promoter region of LaTCTP was cloned using an improved TAIL-PCR technique. In this region we identified many important potential cis-acting elements, such as a Box-W1 (fungal elicitor responsive element), a CAT-box (cis-acting regulatory element related to meristem expression), a CGTCA-motif (cis-acting regulatory element involved in MeJA-responsiveness), a GT1-motif (light responsive element), a Skn-1-motif (cis-acting regulatory element required for endosperm expression) and a TGA-element (auxin-responsive element), suggesting that expression of LaTCTP is highly regulated. Expression analysis demonstrated ubiquitous localization of LaTCTP mRNA in the roots, stems and needles, high mRNA levels in the embryonal-suspensor mass (ESM), browning embryogenic cultures and mature somatic embryos, and low levels of mRNA at day five during somatic embryogenesis. We suggest that LaTCTP might participate in the regulation of somatic embryo development. These results provide a theoretical basis for understanding the molecular regulatory mechanism of LaTCTP and lay the foundation for artificial regulation of somatic embryogenesis. © 2013.

Interaction between two cis-acting elements, ABRE and DRE, in ABA-dependent expression of Arabidopsis rd29A gene in response to dehydration and high-salinity stresses.

PubMed

Narusaka, Yoshihiro; Nakashima, Kazuo; Shinwari, Zabta K; Sakuma, Yoh; Furihata, Takashi; Abe, Hiroshi; Narusaka, Mari; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2003-04-01

Many abiotic stress-inducible genes contain two cis-acting elements, namely a dehydration-responsive element (DRE; TACCGACAT) and an ABA-responsive element (ABRE; ACGTGG/TC), in their promoter regions. We precisely analyzed the 120 bp promoter region (-174 to -55) of the Arabidopsis rd29A gene whose expression is induced by dehydration, high-salinity, low-temperature, and abscisic acid (ABA) treatments and whose 120 bp promoter region contains the DRE, DRE/CRT-core motif (A/GCCGAC), and ABRE sequences. Deletion and base substitution analyses of this region showed that the DRE-core motif functions as DRE and that the DRE/DRE-core motif could be a coupling element of ABRE. Gel mobility shift assays revealed that DRE-binding proteins (DREB1s/CBFs and DREB2s) bind to both DRE and the DRE-core motif and that ABRE-binding proteins (AREBs/ABFs) bind to ABRE in the 120 bp promoter region. In addition, transactivation experiments using Arabidopsis leaf protoplasts showed that DREBs and AREBs cumulatively transactivate the expression of a GUS reporter gene fused to the 120 bp promoter region of rd29A. These results indicate that DRE and ABRE are interdependent in the ABA-responsive expression of the rd29A gene in response to ABA in Arabidopsis.

Functional analysis of the stress response element and its role in the multistress response of Saccharomyces cerevisiae.

PubMed

Treger, J M; Magee, T R; McEntee, K

1998-02-04

The DDR2 gene of Saccharomyces cerevisiae is a multistress response gene whose transcription is rapidly and strongly induced by a diverse array of xenobiotic agents, and environmental and physiological conditions. The multistress response of this gene requires the pentanucleotide, 5' CCCCT, (C4T;STRE (STress Response Element)) and the zinc-finger transcription factors, Msn2p and Msn4p. A 51bp oligonucleotide (oligo 31/32) containing two STREs from the DDR2 promoter region was previously shown to direct heat shock activation of a lacZ reporter gene. In this work we demonstrate that the same element conferred a complete multistress response to an E. coli galK reporter gene introduced into yeast cells. A variant oligonucleotide in which both the STRE spacing and neighboring sequences were altered responded to the same spectrum of stresses, while substitution of nucleotides within the pentanucleotide completely abolished the multistress response. These results directly demonstrate that STREs are not only necessary but are sufficient for mediating a transcriptional response to a surprisingly diverse set of environmental and physiological conditions.

Active muscle response using feedback control of a finite element human arm model.

PubMed

Östh, Jonas; Brolin, Karin; Happee, Riender

2012-01-01

Mathematical human body models (HBMs) are important research tools that are used to study the human response in car crash situations. Development of automotive safety systems requires the implementation of active muscle response in HBM, as novel safety systems also interact with vehicle occupants in the pre-crash phase. In this study, active muscle response was implemented using feedback control of a nonlinear muscle model in the right upper extremity of a finite element (FE) HBM. Hill-type line muscle elements were added, and the active and passive properties were assessed. Volunteer tests with low impact loading resulting in elbow flexion motions were performed. Simulations of posture maintenance in a gravity field and the volunteer tests were successfully conducted. It was concluded that feedback control of a nonlinear musculoskeletal model can be used to obtain posture maintenance and human-like reflexive responses in an FE HBM.

Determination of apparent coupling factors for adhesive bonded acrylic plates using SEAL approach

NASA Astrophysics Data System (ADS)

Pankaj, Achuthan. C.; Shivaprasad, M. V.; Murigendrappa, S. M.

2018-04-01

Apparent coupling loss factors (CLF) and velocity responses has been computed for two lap joined adhesive bonded plates using finite element and experimental statistical energy analysis like approach. A finite element model of the plates has been created using ANSYS software. The statistical energy parameters have been computed using the velocity responses obtained from a harmonic forced excitation analysis. Experiments have been carried out for two different cases of adhesive bonded joints and the results have been compared with the apparent coupling factors and velocity responses obtained from finite element analysis. The results obtained from the studies signify the importance of modeling of adhesive bonded joints in computation of the apparent coupling factors and its further use in computation of energies and velocity responses using statistical energy analysis like approach.

Senescence responsive transcriptional element

DOEpatents

Campisi, Judith; Testori, Alessandro

1999-01-01

Recombinant polynucleotides have expression control sequences that have a senescence responsive element and a minimal promoter, and which are operatively linked to a heterologous nucleotide sequence. The molecules are useful for achieving high levels of expression of genes in senescent cells. Methods of inhibiting expression of genes in senescent cells also are provided.

Profiling Environmental Chemicals in the Antioxidant Response Element Pathway using Quantitative High Throughput Screening (qHTS)

EPA Science Inventory

The antioxidant response element (ARE) signaling pathway plays an important role in the amelioration of oxidative stress, which can contribute to a number of diseases, including cancer. We screened 1408 NTP-provided substances in 1536-well qHTS format at concentrations ranging fr...

Infrasound-array-element frequency response: in-situ measurement and modeling

NASA Astrophysics Data System (ADS)

Gabrielson, T.

2011-12-01

Most array elements at the infrasound stations of the International Monitoring System use some variant of a multiple-inlet pipe system for wind-noise suppression. These pipe systems have a significant impact on the overall frequency response of the element. The spatial distribution of acoustic inlets introduces a response dependence that is a function of frequency and of vertical and horizontal arrival angle; the system of inlets, pipes, and summing junctions further shapes that response as the signal is ducted to the transducer. In-situ measurements, using a co-located reference microphone, can determine the overall frequency response and diagnose problems with the system. As of July 2011, the in-situ frequency responses for 25 individual elements at 6 operational stations (I10, I53, I55, I56, I57, and I99) have been measured. In support of these measurements, a fully thermo-viscous model for the acoustics of these multiple-inlet pipe systems has been developed. In addition to measurements at operational stations, comparative analyses have been done on experimental systems: a multiple-inlet radial-pipe system with varying inlet hole size; a one-quarter scale model of a 70-meter rosette system; and vertical directionality of a small rosette system using aircraft flyovers. [Funded by the US Army Space and Missile Defense Command

Genetic Nature of Elemental Contents in Wheat Grains and Its Genomic Prediction: Toward the Effective Use of Wheat Landraces from Afghanistan

PubMed Central

Yamaoka, Shuhei; Yoshimura, Kazusa; Kondou, Youichi; Onogi, Akio; Matsui, Minami; Iwata, Hiroyoshi; Ban, Tomohiro

2017-01-01

Profiling elemental contents in wheat grains and clarifying the underlying genetic systems are important for the breeding of biofortified crops. Our objective was to evaluate the genetic potential of 269 Afghan wheat landraces for increasing elemental contents in wheat cultivars. The contents of three major (Mg, K, and P) and three minor (Mn, Fe, and Zn) elements in wheat grains were measured by energy dispersive X-ray fluorescence spectrometry. Large variations in elemental contents were observed among landraces. Marker-based heritability estimates were low to moderate, suggesting that the elemental contents are complex quantitative traits. Genetic correlations between two locations (Japan and Afghanistan) and among the six elements were estimated using a multi-response Bayesian linear mixed model. Low-to-moderate genetic correlations were observed among major elements and among minor elements respectively, but not between major and minor elements. A single-response genome-wide association study detected only one significant marker, which was associated with Zn, suggesting it will be difficult to increase the elemental contents of wheat by conventional marker-assisted selection. Genomic predictions for major elemental contents were moderately or highly accurate, whereas those for minor elements were mostly low or moderate. Our results indicate genomic selection may be useful for the genetic improvement of elemental contents in wheat. PMID:28072876

Implementation of structural response sensitivity calculations in a large-scale finite-element analysis system

NASA Technical Reports Server (NTRS)

Giles, G. L.; Rogers, J. L., Jr.

1982-01-01

The methodology used to implement structural sensitivity calculations into a major, general-purpose finite-element analysis system (SPAR) is described. This implementation includes a generalized method for specifying element cross-sectional dimensions as design variables that can be used in analytically calculating derivatives of output quantities from static stress, vibration, and buckling analyses for both membrane and bending elements. Limited sample results for static displacements and stresses are presented to indicate the advantages of analytically calculating response derivatives compared to finite difference methods. Continuing developments to implement these procedures into an enhanced version of SPAR are also discussed.

Motor programming when sequencing multiple elements of the same duration.

PubMed

Magnuson, Curt E; Robin, Donald A; Wright, David L

2008-11-01

Motor programming at the self-select paradigm was adopted in 2 experiments to examine the processing demands of independent processes. One process (INT) is responsible for organizing the internal features of the individual elements in a movement (e.g., response duration). The 2nd process (SEQ) is responsible for placing the elements into the proper serial order before execution. Participants in Experiment 1 performed tasks involving 1 key press or sequences of 4 key presses of the same duration. Implementing INT and SEQ was more time consuming for key-pressing sequences than for single key-press tasks. Experiment 2 examined whether the INT costs resulting from the increase in sequence length observed in Experiment 1 resulted from independent planning of each sequence element or via a separate "multiplier" process that handled repetitions of elements of the same duration. Findings from Experiment 2, in which participants performed single key presses or double or triple key sequences of the same duration, suggested that INT is involved with the independent organization of each element contained in the sequence. Researchers offer an elaboration of the 2-process account of motor programming to incorporate the present findings and the findings from other recent sequence-learning research.

Finite-element model of the active organ of Corti

PubMed Central

Elliott, Stephen J.; Baumgart, Johannes

2016-01-01

The cochlear amplifier that provides our hearing with its extraordinary sensitivity and selectivity is thought to be the result of an active biomechanical process within the sensory auditory organ, the organ of Corti. Although imaging techniques are developing rapidly, it is not currently possible, in a fully active cochlea, to obtain detailed measurements of the motion of individual elements within a cross section of the organ of Corti. This motion is predicted using a two-dimensional finite-element model. The various solid components are modelled using elastic elements, the outer hair cells (OHCs) as piezoelectric elements and the perilymph and endolymph as viscous and nearly incompressible fluid elements. The model is validated by comparison with existing measurements of the motions within the passive organ of Corti, calculated when it is driven either acoustically, by the fluid pressure or electrically, by excitation of the OHCs. The transverse basilar membrane (BM) motion and the shearing motion between the tectorial membrane and the reticular lamina are calculated for these two excitation modes. The fully active response of the BM to acoustic excitation is predicted using a linear superposition of the calculated responses and an assumed frequency response for the OHC feedback. PMID:26888950

Unification of color postprocessing techniques for 3-dimensional computational mechanics

NASA Technical Reports Server (NTRS)

Bailey, Bruce Charles

1985-01-01

To facilitate the understanding of complex three-dimensional numerical models, advanced interactive color postprocessing techniques are introduced. These techniques are sufficiently flexible so that postprocessing difficulties arising from model size, geometric complexity, response variation, and analysis type can be adequately overcome. Finite element, finite difference, and boundary element models may be evaluated with the prototype postprocessor. Elements may be removed from parent models to be studied as independent subobjects. Discontinuous responses may be contoured including responses which become singular, and nonlinear color scales may be input by the user for the enhancement of the contouring operation. Hit testing can be performed to extract precise geometric, response, mesh, or material information from the database. In addition, stress intensity factors may be contoured along the crack front of a fracture model. Stepwise analyses can be studied, and the user can recontour responses repeatedly, as if he were paging through the response sets. As a system, these tools allow effective interpretation of complex analysis results.

Trajectory Control and Optimization for Responsive Spacecraft

DTIC Science & Technology

2012-03-22

Orbital Elements and Local-Vertical-Local-Horizontal Frame 10 2.3 Equinoctial Frame with respect to ECI Frame [17] . . . . . . . . . 14 3.1...position and velocity, classical orbital elements , and equinoctial elements . These methods are detailed in the following sections. 2.1.1 Inertial Position...trajectory. However, if the singularities are unavoidable equinoctial orbital elements could be used. 2.1.3 Equinoctial Elements . Equinoctial

Transcriptional switches in the control of macronutrient metabolism.

PubMed

Wise, Alan

2008-06-01

This review shows how some transcription factors respond to alterations in macronutrients. Carbohydrates induce enzymes for their metabolism and fatty acid synthesis. Fatty acids reduce carbohydrate processing, induce enzymes for their metabolism, and increase both gluconeogenesis and storage of fat. Fat stores help control carbohydrate uptake by other cells. The following main transcription factors are discussed: carbohydrate response element-binding protein; sterol regulatory element-binding protein-1c, cyclic AMP response element-binding protein, peroxisome proliferator-activated receptor-alpha, and peroxisome proliferator-activated receptor-gamma.

Implementation of structural response sensitivity calculations in a large-scale finite-element analysis system

NASA Technical Reports Server (NTRS)

Giles, G. L.; Rogers, J. L., Jr.

1982-01-01

The implementation includes a generalized method for specifying element cross-sectional dimensions as design variables that can be used in analytically calculating derivatives of output quantities from static stress, vibration, and buckling analyses for both membrane and bending elements. Limited sample results for static displacements and stresses are presented to indicate the advantages of analytically calclating response derivatives compared to finite difference methods. Continuing developments to implement these procedures into an enhanced version of the system are also discussed.

The structure of distractor-response bindings: Conditions for configural and elemental integration.

PubMed

Moeller, Birte; Frings, Christian; Pfister, Roland

2016-04-01

Human action control is influenced by bindings between perceived stimuli and responses carried out in their presence. Notably, responses given to a target stimulus can also be integrated with additional response-irrelevant distractor stimuli that accompany the target (distractor-response binding). Subsequently reencountering such a distractor then retrieves the associated response. Although a large body of evidence supports the existence of this effect, the specific structure of distractor-response bindings is still unclear. Here, we test the predictions derived from 2 possible assumptions about the structure of bindings between distractors and responses. According to a configural approach, the entire distractor object is integrated with a response, and only upon repetition of the entire distractor object the associated response would be retrieved. According to an elemental approach, one would predict integration of individual distractor features with the response and retrieval due to the repetition of an individual distractor feature. Four experiments indicate that both, configural and elemental bindings exist and specify boundary conditions for each type of binding. These findings provide detailed insights into the architecture of bindings between response-irrelevant stimuli and actions and thus allow for specifying how distractor stimuli influence human behavior. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Transcriptional regulation of ABI3- and ABA-responsive genes including RD29B and RD29A in seeds, germinating embryos, and seedlings of Arabidopsis.

PubMed

Nakashima, Kazuo; Fujita, Yasunari; Katsura, Koji; Maruyama, Kyonoshin; Narusaka, Yoshihiro; Seki, Motoaki; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2006-01-01

ABA-responsive elements (ABREs) are cis-acting elements and basic leucine zipper (bZIP)-type ABRE-binding proteins (AREBs) are transcriptional activators that function in the expression of RD29B in vegetative tissue of Arabidopsis in response to abscisic acid (ABA) treatment. Dehydration-responsive elements (DREs) function as coupling elements of ABRE in the expression of RD29A in response to ABA. Expression analysis using abi3 and abi5 mutants showed that ABI3 and ABI5 play important roles in the expression of RD29B in seeds. Base-substitution analysis showed that two ABREs function strongly and one ABRE coupled with DRE functions weakly in the expression of RD29A in embryos. In a transient transactivation experiment, ABI3, ABI5 and AREB1 activated transcription of a GUS reporter gene driven by the RD29B promoter strongly but these proteins activated the transcription driven by the RD29A promoter weakly. In 35S::ABI3 Arabidopsis plants, the expression of RD29B was up-regulated strongly, but that of RD29A was up-regulated weakly. These results indicate that the expression of RD29B having ABREs in the promoter is up-regulated strongly by ABI3, whereas that of RD29A having one ABRE coupled with DREs in the promoter is up-regulated weakly by ABI3. We compared the expression of 7000 Arabidopsis genes in response to ABA treatment during germination and in the vegetative growth stage, and that in 35S::ABI3 plants using a full-length cDNA microarray. The expression of ABI3- and/or ABA-responsive genes and cis-elements in the promoters are discussed.

Trace elements in coal ash

USGS Publications Warehouse

Deonarine, Amrika; Kolker, Allan; Doughten, Michael W.

2015-01-01

In this fact sheet, the form, distribution, and behavior of trace elements of environmental interest in samples of coal fly ash were investigated in response to concerns about element mobility in the event of an ash spill. The study includes laboratory-based leaching experiments to examine the behavior of trace elements, such as arsenic (As) and chromium (Cr), in response to key environmental factors including redox conditions (degree of oxygenation), which are known to vary with depth within coal ash impoundments and in natural ecosystems. The experiments show that As dissolves from samples of coal fly ash into simulated freshwater under both oxic (highly oxygenated) and anoxic (poorly oxygenated) conditions, whereas dissolved Cr concentrations are very redox dependent. This U.S. Geological Survey research helps define the distribution of elements such as As in coal ash and shows that element mobility can vary considerably under different conditions expected in the environment.

Response of hot element flush wall gauges in oscillating laminar flow

NASA Technical Reports Server (NTRS)

Giddings, T. A.; Cook, W. J.

1986-01-01

The time dependent response characteristics of flush-mounted hot element gauges used as instruments to measure wall shear stress in unsteady periodic air flows were investigated. The study was initiated because anomalous results were obtained from the gauges in oscillating turbulent flows for the phase relation of the wall shear stress variation, indicating possible gauge response problems. Flat plate laminar oscillating turbulent flows characterized by a mean free stream velocity with a superposed sinusoidal variation were performed. Laminar rather than turbulent flows were studied, because a numerical solution for the phase angle between the free stream velocity and the wall shear stress variation that is known to be correct can be obtained. The focus is on comparing the phase angle indicated by the hot element gauges with corresponding numerical prediction for the phase angle, since agreement would indicate that the hot element gauges faithfully follow the true wall shear stress variation.

An ABA-responsive DRE-binding protein gene from Setaria italica, SiARDP, the target gene of SiAREB, plays a critical role under drought stress.

PubMed

Li, Cong; Yue, Jing; Wu, Xiaowei; Xu, Cong; Yu, Jingjuan

2014-10-01

The DREB (dehydration-responsive element binding)-type transcription factors regulate the expression of stress-inducible genes by binding the DRE/CRT cis-elements in promoter regions. The upstream transcription factors that regulate the transcription of DREB transcription factors have not been clearly defined, although the function of DREB transcription factors in abiotic stress is known. In this study, an abscisic acid (ABA)-responsive DREB-binding protein gene (SiARDP) was cloned from foxtail millet (Setaria italica). The transcript level of SiARDP increased not only after drought, high salt, and low temperature stresses, but also after an ABA treatment in foxtail millet seedlings. Two ABA-responsive elements (ABRE1: ACGTGTC; ABRE2: ACGTGGC) exist in the promoter of SiARDP. Further analyses showed that two ABA-responsive element binding (AREB)-type transcription factors, SiAREB1 and SiAREB2, could physically bind to the ABRE core element in vitro and in vivo. The constitutive expression of SiARDP in Arabidopsis thaliana enhanced drought and salt tolerance during seed germination and seedling development, and overexpression of SiARDP in foxtail millet improved drought tolerance. The expression levels of target genes of SiARDP were upregulated in transgenic Arabidopsis and foxtail millet. These results reveal that SiARDP, one of the target genes of SiAREB, is involved in ABA-dependent signal pathways and plays a critical role in the abiotic stress response in plants. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Nonlinear solid finite element analysis of mitral valves with heterogeneous leaflet layers

NASA Astrophysics Data System (ADS)

Prot, V.; Skallerud, B.

2009-02-01

An incompressible transversely isotropic hyperelastic material for solid finite element analysis of a porcine mitral valve response is described. The material model implementation is checked in single element tests and compared with a membrane implementation in an out-of-plane loading test to study how the layered structures modify the stress response for a simple geometry. Three different collagen layer arrangements are used in finite element analysis of the mitral valve. When the leaflets are arranged in two layers with the collagen on the ventricular side, the stress in the fibre direction through the thickness in the central part of the anterior leaflet is homogenized and the peak stress is reduced. A simulation using membrane elements is also carried out for comparison with the solid finite element results. Compared to echocardiographic measurements, the finite element models bulge too much in the left atrium. This may be due to evidence of active muscle fibres in some parts of the anterior leaflet, whereas our constitutive modelling is based on passive material.

Non-volatile, solid state bistable electrical switch

NASA Technical Reports Server (NTRS)

Williams, Roger M. (Inventor)

1994-01-01

A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state. Application of the electrical potential in the opposite direction causes reverse current flow which de-intercalates the bistable logic switching element and produces a high resistance logic state.

Finite element simulations of the head-brain responses to the top impacts of a construction helmet: Effects of the neck and body mass.

PubMed

Wu, John Z; Pan, Christopher S; Wimer, Bryan M; Rosen, Charles L

2017-01-01

Traumatic brain injuries are among the most common severely disabling injuries in the United States. Construction helmets are considered essential personal protective equipment for reducing traumatic brain injury risks at work sites. In this study, we proposed a practical finite element modeling approach that would be suitable for engineers to optimize construction helmet design. The finite element model includes all essential anatomical structures of a human head (i.e. skin, scalp, skull, cerebrospinal fluid, brain, medulla, spinal cord, cervical vertebrae, and discs) and all major engineering components of a construction helmet (i.e. shell and suspension system). The head finite element model has been calibrated using the experimental data in the literature. It is technically difficult to precisely account for the effects of the neck and body mass on the dynamic responses, because the finite element model does not include the entire human body. An approximation approach has been developed to account for the effects of the neck and body mass on the dynamic responses of the head-brain. Using the proposed model, we have calculated the responses of the head-brain during a top impact when wearing a construction helmet. The proposed modeling approach would provide a tool to improve the helmet design on a biomechanical basis.

Plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to phosphorus in acid soils.

PubMed

Barbosa, Julierme Z; Motta, Antonio C V; Consalter, Rangel; Poggere, Giovana C; Santin, Delmar; Wendling, Ivar

2018-01-01

Native to subtropical region of South America, yerba mate is responsive to P under some conditions, but the degree of influence of genetic and soil on the growth and composition of the leaf is unknown. The aim of study was to evaluate plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to P application in acid soils. In greenhouse condition, two yerba mate clone seedlings were grown (210 days) in pots, each clone in a completely randomized design in factorial scheme (with and without P; four acid soils). The elemental composition of leaves and the growth of plants were determined. Phosphorus promoted plant growth, but this was not accompanied by increased P in leaf tissue in all conditions tested. The P effect on the elemental composition varied: decrease/null (N, K, Mg, Mn, Cu, Ni, B, Mo, Al, Cd); increase/null (C/N, C, Ca, Fe, V); increase/decrease/null (Zn, Ba, Pb) and; null (Cr). The soils affect the elemental composition of the leaves, especially Mn, with accumulation greater than 1000 mg kg-1. The Ba, Pb, Al and Zn in the leaves varied among clones. Yerba mate response to P was affected by edaphic and plant factors.

Integration of P, S, Fe, and Zn nutrition signals in Arabidopsis thaliana: potential involvement of PHOSPHATE STARVATION RESPONSE 1 (PHR1)

PubMed Central

Briat, Jean-François; Rouached, Hatem; Tissot, Nicolas; Gaymard, Frédéric; Dubos, Christian

2015-01-01

Phosphate and sulfate are essential macro-elements for plant growth and development, and deficiencies in these mineral elements alter many metabolic functions. Nutritional constraints are not restricted to macro-elements. Essential metals such as zinc and iron have their homeostasis strictly genetically controlled, and deficiency or excess of these micro-elements can generate major physiological disorders, also impacting plant growth and development. Phosphate and sulfate on one hand, and zinc and iron on the other hand, are known to interact. These interactions have been partly described at the molecular and physiological levels, and are reviewed here. Furthermore the two macro-elements phosphate and sulfate not only interact between themselves but also influence zinc and iron nutrition. These intricated nutritional cross-talks are presented. The responses of plants to phosphorus, sulfur, zinc, or iron deficiencies have been widely studied considering each element separately, and some molecular actors of these regulations have been characterized in detail. Although some scarce reports have started to examine the interaction of these mineral elements two by two, a more complex analysis of the interactions and cross-talks between the signaling pathways integrating the homeostasis of these various elements is still lacking. However, a MYB-like transcription factor, PHOSPHATE STARVATION RESPONSE 1, emerges as a common regulator of phosphate, sulfate, zinc, and iron homeostasis, and its role as a potential general integrator for the control of mineral nutrition is discussed. PMID:25972885

Dual-frequency super harmonic imaging piezoelectric transducers for transrectal ultrasound

NASA Astrophysics Data System (ADS)

Kim, Jinwook; Li, Sibo; Kasoji, Sandeep; Dayton, Paul A.; Jiang, Xiaoning

2015-03-01

In this paper, a 2/14 MHz dual-frequency single-element transducer and a 2/22 MHz sub-array (16/48-elements linear array) transducer were developed for contrast enhanced super-harmonic ultrasound imaging of prostate cancer with the low frequency ultrasound transducer as a transmitter for contrast agent (microbubble) excitation and the high frequency transducer as a receiver for detection of nonlinear responses from microbubbles. The 1-3 piezoelectric composite was used as active materials of the single-element transducers due to its low acoustic impedance and high coupling factor. A high dielectric constant PZT ceramic was used for the sub-array transducer due to its high dielectric property induced relatively low electrical impedance. The possible resonance modes of the active elements were estimated using finite element analysis (FEA). The pulse-echo response, peak-negative pressure and bubble response were tested, followed by in vitro contrast imaging tests using a graphite-gelatin tissue-mimicking phantom. The single-element dual frequency transducer (8 × 4 × 2 mm3) showed a -6 dB fractional bandwidth of 56.5% for the transmitter, and 41.8% for the receiver. A 2 MHz-transmitter (730 μm pitch and 6.5 mm elevation aperture) and a 22 MHz-receiver (240 μm pitch and 1.5 mm aperture) of the sub-array transducer exhibited -6 dB fractional bandwidth of 51.0% and 40.2%, respectively. The peak negative pressure at the far field was about -1.3 MPa with 200 Vpp, 1-cycle 2 MHz burst, which is high enough to excite microbubbles for nonlinear responses. The 7th harmonic responses from micro bubbles were successfully detected in the phantom imaging test showing a contrast-to-tissue ratio (CTR) of 16 dB.

Stacked Switchable Element and Diode Combination

DOEpatents

Branz, H. M.; Wang, Q.

2006-06-27

A device (10) comprises a semiconductor diode (12) and a switchable element (14) positioned in stacked adjacent relationship so that the semiconductor diode (12) and the switchable element (14) are electrically connected in series with one another. The switchable element (14) is switchable from a low-conductance state to a high-conductance state in response to the application of a forming voltage to the switchable element (14).

Stacked switchable element and diode combination

DOEpatents

Branz, Howard M.; Wang, Qi

2006-06-27

A device (10) comprises a semiconductor diode (12) and a switchable element (14) positioned in stacked adjacent relationship so that the semiconductor diode (12) and the switchable element (14) are electrically connected in series with one another. The switchable element (14) is switchable from a low-conductance state to a high-conductance state in response to the application of a forming voltage to the switchable element (14).

The Nrf2-antioxidant response element pathway: a target for regulating energy metabolism

USDA-ARS?s Scientific Manuscript database

The nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that responds to oxidative stress by binding to the antioxidant response element (ARE) in the promoter of genes coding for antioxidant enzymes like NAD(P)H:quinone oxidoreductase 1 (NQO1) and proteins for glutathione synthesis. ...

Teaching and Reaching All Students: An Instructional Model for Closing the Gap

ERIC Educational Resources Information Center

Powell, Rebecca; Cantrell, Susan Chambers; Rightmyer, Elizabeth

2013-01-01

This article presents a model for culturally responsive instruction (CRI) that represents a synthesis of research on effective literacy and content instruction for diverse middle grades learners.The article discusses the various elements of the Culturally Responsive Instruction Observation Protocol (CRIOP) model. It then examines these elements by…

Profiling Environmental Chemicals for Activity in the Antioxidant Response Element Signaling Pathway Using a High-Throughput Screening Approach

EPA Science Inventory

1 ABSTRACT 2 3 BACKGROUND: Oxidative stress has been implicated in the pathogenesis of a variety 4 of diseases ranging from cancer to neurodegeneration, highlighti.ng the need to identify 5 chemicals that can induce this effect. The antioxidant response element (ARE)...

Probabilistic finite elements

NASA Technical Reports Server (NTRS)

Belytschko, Ted; Wing, Kam Liu

1987-01-01

In the Probabilistic Finite Element Method (PFEM), finite element methods have been efficiently combined with second-order perturbation techniques to provide an effective method for informing the designer of the range of response which is likely in a given problem. The designer must provide as input the statistical character of the input variables, such as yield strength, load magnitude, and Young's modulus, by specifying their mean values and their variances. The output then consists of the mean response and the variance in the response. Thus the designer is given a much broader picture of the predicted performance than with simply a single response curve. These methods are applicable to a wide class of problems, provided that the scale of randomness is not too large and the probabilistic density functions possess decaying tails. By incorporating the computational techniques we have developed in the past 3 years for efficiency, the probabilistic finite element methods are capable of handling large systems with many sources of uncertainties. Sample results for an elastic-plastic ten-bar structure and an elastic-plastic plane continuum with a circular hole subject to cyclic loadings with the yield stress on the random field are given.

Structural characterization of a novel full-length transcript promoter from Horseradish Latent Virus (HRLV) and its transcriptional regulation by multiple stress responsive transcription factors.

PubMed

Khan, Ahamed; Shrestha, Ankita; Bhuyan, Kashyap; Maiti, Indu B; Dey, Nrisingha

2018-01-01

The promoter fragment described in this study can be employed for strong transgene expression under both biotic and abiotic stress conditions. Plant-infecting Caulimoviruses have evolved multiple regulatory mechanisms to address various environmental stimuli during the course of evolution. One such mechanism involves the retention of discrete stress responsive cis-elements which are required for their survival and host-specificity. Here we describe the characterization of a novel Caulimoviral promoter isolated from Horseradish Latent Virus (HRLV) and its regulation by multiple stress responsive Transcription factors (TFs) namely DREB1, AREB1 and TGA1a. The activity of full length transcript (Flt-) promoter from HRLV (- 677 to + 283) was investigated in both transient and transgenic assays where we identified H12 (- 427 to + 73) as the highest expressing fragment having ~ 2.5-fold stronger activity than the CaMV35S promoter. The H12 promoter was highly active and near-constitutive in the vegetative and reproductive parts of both Tobacco and Arabidopsis transgenic plants. Interestingly, H12 contains a distinct cluster of cis-elements like dehydration-responsive element (DRE-core; GCCGAC), an ABA-responsive element (ABRE; ACGTGTC) and as-1 element (TGACG) which are known to be induced by cold, drought and pathogen/SA respectively. The specific binding of DREB1, AREB1 and TGA1a to DRE, ABRE and as-1 elements respectively were confirmed by the gel-binding assays using H12 promoter-specific probes. Detailed mutational analysis of the H12 promoter suggested that the presence of DRE-core and as-1 element was indispensable for its activity which was further confirmed by the transactivation assays. Our studies imply that H12 could be a valuable genetic tool for regulated transgene expression under diverse environmental conditions.

Characterization of promoter of EgPAL1, a novel PAL gene from the oil palm Elaeis guineensis Jacq.

PubMed

Yusuf, Chong Yu Lok; Abdullah, Janna Ong; Shaharuddin, Noor Azmi; Abu Seman, Idris; Abdullah, Mohd Puad

2018-02-01

The oil palm EgPAL1 gene promoter and its regulatory region were functional as a promoter in the heterologous system of Arabidopsis according to the cis-acting elements present in that region. The promoter was developmentally regulated, vascular tissue specific and responsive to water stress agents. Phenylalanine ammonia lyase (PAL, EC 4.3.1.24) is the key enzyme of the phenylpropanoid pathway which plays important roles in plant development and adaptation. To date, there is no report on the study of PAL from oil palm (Elaeis guineensis), an economically important oil crop. In this study, the 5' regulatory sequence of a highly divergent oil palm PAL gene (EgPAL1) was isolated and fused with GUS in Arabidopsis to create two transgenic plants carrying the minimal promoter with (2302 bp) and without its regulatory elements (139 bp). The regulatory sequence contained cis-acting elements known to be important for plant development and stress response including the AC-II element for lignin biosynthesis and several stress responsive elements. The promoter and its regulatory region were fully functional in Arabidopsis. Its activities were characterised by two common fundamental features of PAL which are responsive to plant internal developmental programme and external factors. The promoter was developmentally regulated in certain organs; highly active in young organs but less active or inactive in mature organs. The presence of the AC elements and global activity of the EgPAL1 promoter in all organs resembled the property of lignin-related genes. The existence of the MBS element and enhancement of the promoter activity by PEG reflected the behaviour of drought-responsive genes. Our findings provide a platform for evaluating oil palm gene promoters in the heterologous system of Arabidopsis and give insights into the activities of EgPAL1 promoter in oil palm.

Identification of an estrogen response element in the 3'-flanking region of the murine c-fos protooncogene.

PubMed

Hyder, S M; Stancel, G M; Nawaz, Z; McDonnell, D P; Loose-Mitchell, D S

1992-09-05

We have used transient transfection assays with reporter plasmids expressing chloramphenicol acetyltransferase, linked to regions of mouse c-fos, to identify a specific estrogen response element (ERE) in this protooncogene. This element is located in the untranslated 3'-flanking region of the c-fos gene, 5 kilobases (kb) downstream from the c-fos promoter and 1.5 kb downstream of the poly(A) signal. This element confers estrogen responsiveness to chloramphenicol acetyltransferase reporters linked to both the herpes simplex virus thymidine kinase promoter and the homologous c-fos promoter. Deletion analysis localized the response element to a 200-base pair fragment which contains the element GGTCACCACAGCC that resembles the consensus ERE sequence GGTCACAGTGACC originally identified in Xenopus vitellogenin A2 gene. A synthetic 36-base pair oligodeoxynucleotide containing this c-fos sequence conferred estrogen inducibility to the thymidine kinase promoter. The corresponding sequence also induced reporter activity when present in the c-fos gene fragment 3 kb from the thymidine kinase promoter. Gel-shift experiments demonstrated that synthetic oligonucleotides containing either the consensus ERE or the c-fos element bind human estrogen receptor obtained from a yeast expression system. However, the mobility of the shifted band is faster for the fos-ERE-complex than the consensus ERE complex suggesting that the three-dimensional structure of the protein-DNA complexes is different or that other factors are differentially involved in the two reactions. When the 5'-GGTCA sequence present in the c-fos ERE is mutated to 5'-TTTCA, transcriptional activation and receptor binding activities are both lost. Mutation of the CAGCC-3' element corresponding to the second half-site of the c-fos sequence also led to the loss of receptor binding activity, suggesting that both half-sites of this element are involved in this function. The estrogen induction mediated by either the c-fos or the consensus ERE was blunted by the antiestrogen tamoxifen. Based on these studies, we believe the 3'-fos ERE sequence we have identified may be a major cis-acting element involved in the physiological regulation of the gene by estrogens in vivo.

System Response Manipulation using Arrays of Subordinate Resonators: Theory and Applications

NASA Astrophysics Data System (ADS)

Glean, Aldo A. J.

The dynamic response of a resonant structure can be significantly altered by the attachment of an array of substantially smaller resonators. This dissertation presents the theory governing these subordinate oscillator arrays (SOAs) and explores four major applications of using the arrays. The first application is related to vibration suppression. Numerical optimization was used to obtain SOA properties that minimize the settling time of a primary resonator subjected to an impulse. This minimization was conducted for system characteristics including the overall bandwidth of the array, the ratio of total array mass to primary resonator mass, and distributions of array properties. It is shown that the minimum settling time is a function of bandwidth and added mass within the SOA. The second application introduces a novel method of chemical vapor detection using SOA elements that are functionalized to bond with a specific chemical species. Numerical simulations were used to relate mass adsorbed to changes in the time-domain response of the system. It is shown that increasing the number of sensing elements increases sensitivity and reduces errors in mass predictions due to mass adsorption variability while having fewer sensing elements increases signal-to-noise ratio. The third application is also concerned with chemical vapor detection. Numerical simulation was used to explore the changes in system resonant frequencies and normal mode shapes in response to adsorption of mass on a single array element, in arrays in which each element has a distinct resonant frequency. It is shown that the degree of inter-element coupling is proportional to the ratio of the mass of the elements to the primary resonator mass. Inter-element coupling was also found to increase linearly with decreasing system resonance spacing up to a maximum value that depends on the mass ratio. The final application is an experimental validation of SOA theory by application to an acoustic system. The third resonance of a standing wave tube is transformed into a bandpass response using an array of small Helmholtz resonators. This experimental work demonstrates that the SOA theory can be applied analogous systems.

Hypoxia-induced endothelial NO synthase gene transcriptional activation is mediated through the tax-responsive element in endothelial cells.

PubMed

Min, Jiho; Jin, Yoon-Mi; Moon, Je-Sung; Sung, Min-Sun; Jo, Sangmee Ahn; Jo, Inho

2006-06-01

Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O2) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (-1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(-1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36+/-0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(-1600). However, progressive 5'-deletion from -1600 to -873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element-like site, located at -924 to -921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression.

Light modulating device

DOEpatents

Rauh, R. David; Goldner, Ronald B.

1989-01-01

In a device for transmitting light, means for controlling the transmissivity of the device, including a ceramic, reversibly electrochromic, crystalline element having a highly reflective state when injected with electrons and charge compensating ions and a highly transmissive state when the electrons and ions are removed, the crystalline element being characterized as having a reflectivity of at least 50% in the reflective state and not greater than 10% in the transmissive state, and means for modulating the crystalline element between the reflective and transmissive states by injecting ions into the crystalline element in response to an applied electrical current of a first polarity and removing the ions in response to an applied electrical current of a second polarity.

Initial dynamic load estimates during configuration design

NASA Technical Reports Server (NTRS)

Schiff, Daniel

1987-01-01

This analysis includes the structural response to shock and vibration and evaluates the maximum deflections and material stresses and the potential for the occurrence of elastic instability, fatigue and fracture. The required computations are often performed by means of finite element analysis (FEA) computer programs in which the structure is simulated by a finite element model which may contain thousands of elements. The formulation of a finite element model can be time consuming, and substantial additional modeling effort may be necessary if the structure requires significant changes after initial analysis. Rapid methods for obtaining rough estimates of the structural response to shock and vibration are presented for the purpose of providing guidance during the initial mechanical design configuration stage.

Light modulating device

DOEpatents

Rauh, R.D.; Goldner, R.B.

1989-12-26

In a device for transmitting light, means for controlling the transmissivity of the device, including a ceramic, reversibly electrochromic, crystalline element having a highly reflective state when injected with electrons and charge compensating ions and a highly transmissive state when the electrons and ions are removed, the crystalline element being characterized as having a reflectivity of at least 50% in the reflective state and not greater than 10% in the transmissive state, and means for modulating the crystalline element between the reflective and transmissive states by injecting ions into the crystalline element in response to an applied electrical current of a first polarity and removing the ions in response to an applied electrical current of a second polarity are disclosed. 1 fig.

A wireless sequentially actuated microvalve system

NASA Astrophysics Data System (ADS)

Baek, Seung-Ki; Yoon, Yong-Kyu; Jeon, Hye-Seon; Seo, Soonmin; Park, Jung-Hwan

2013-04-01

A wireless microvalve system was fabricated based on induction heating for flow control in microfluidics by sequential valve opening. In this approach, we used paraffin wax as a flow plug, which can be changed from solid to liquid with adjacent heating elements operated by induction heating. Programmable opening of valves was devised by using different thermal responses of metal discs to a magnetic field. Copper and nickel discs with a diameter of 2.5 mm and various thicknesses (50, 100 and 200 µm) were prepared as heating elements by a laser cutting method, and they were integrated in the microfluidic channel as part of the microvalve. A calorimetric test was used to measure the thermal properties of the discs in terms of kinds of metal and disc thickness. Sequential openings of the microvalves were performed using the difference in the thermal response of 100 µm thick copper disc and 50 µm thick nickel disc for short-interval openings and 200 µm thick copper disc and 100-µm-thick nickel disc for long-interval openings. The thermal effect on fluid samples as a result of induction heating of the discs was studied by investigating lysozyme denaturation. More heat was generated in heating elements made of copper than in those made of nickel, implying differences in the thermal response of heating elements made of copper and nickel. Also, the thickness of the heating elements affected the thermal response in the elements. Valve openings for short intervals of 1-5 s and long intervals of 15-23 s were achieved by using two sets of heating elements. There was no significant change in lysozyme activity by increasing the temperature of the heating discs. This study demonstrates that a wireless sequentially actuated microvalve system can provide programmed valve opening, portability, ease of fabrication and operation, disposability, and low cost.

Simulation of dynamics of beam structures with bolted joints using adjusted Iwan beam elements

NASA Astrophysics Data System (ADS)

Song, Y.; Hartwigsen, C. J.; McFarland, D. M.; Vakakis, A. F.; Bergman, L. A.

2004-05-01

Mechanical joints often affect structural response, causing localized non-linear stiffness and damping changes. As many structures are assemblies, incorporating the effects of joints is necessary to produce predictive finite element models. In this paper, we present an adjusted Iwan beam element (AIBE) for dynamic response analysis of beam structures containing joints. The adjusted Iwan model consists of a combination of springs and frictional sliders that exhibits non-linear behavior due to the stick-slip characteristic of the latter. The beam element developed is two-dimensional and consists of two adjusted Iwan models and maintains the usual complement of degrees of freedom: transverse displacement and rotation at each of the two nodes. The resulting element includes six parameters, which must be determined. To circumvent the difficulty arising from the non-linear nature of the inverse problem, a multi-layer feed-forward neural network (MLFF) is employed to extract joint parameters from measured structural acceleration responses. A parameter identification procedure is implemented on a beam structure with a bolted joint. In this procedure, acceleration responses at one location on the beam structure due to one known impulsive forcing function are simulated for sets of combinations of varying joint parameters. A MLFF is developed and trained using the patterns of envelope data corresponding to these acceleration histories. The joint parameters are identified through the trained MLFF applied to the measured acceleration response. Then, using the identified joint parameters, acceleration responses of the jointed beam due to a different impulsive forcing function are predicted. The validity of the identified joint parameters is assessed by comparing simulated acceleration responses with experimental measurements. The capability of the AIBE to capture the effects of bolted joints on the dynamic responses of beam structures, and the efficacy of the MLFF parameter identification procedure, are demonstrated.

Dissection of cis-regulatory element architecture of the rice oleosin gene promoters to assess abscisic acid responsiveness in suspension-cultured rice cells.

PubMed

Kim, Sol; Lee, Soo-Bin; Han, Chae-Seong; Lim, Mi-Na; Lee, Sung-Eun; Yoon, In Sun; Hwang, Yong-Sic

2017-08-01

Oleosins are the most abundant proteins in the monolipid layer surrounding neutral storage lipids that form oil bodies in plants. Several lines of evidence indicate that they are physiologically important for the maintenance of oil body structure and for mobilization of the lipids stored inside. Rice has six oleosin genes in its genome, the expression of all of which was found to be responsive to abscisic acid (ABA) in our examination of mature embryo and aleurone tissues. The 5'-flanking region of OsOle5 was initially characterized for its responsiveness to ABA through a transient expression assay system using the protoplasts from suspension-cultured rice cells. A series of successive deletions and site-directed mutations identified five regions critical for the hormonal induction of its promoter activity. A search for cis-acting elements in these regions deposited in a public database revealed that they contain various promoter elements previously reported to be involved in the ABA response of various genes. A gain-of-function experiment indicated that multiple copies of all five regions were sufficient to provide the minimal promoter with a distinct ABA responsiveness. Comparative sequence analysis of the short, but still ABA-responsive, promoters of OsOle genes revealed no common modular architecture shared by them, indicating that various distinct promoter elements and independent trans-acting factors are involved in the ABA responsiveness of rice oleosin multigenes. Copyright © 2017 Elsevier GmbH. All rights reserved.

Functional analysis of the Arabidopsis PLDZ2 promoter reveals an evolutionarily conserved low-Pi-responsive transcriptional enhancer element

PubMed Central

Oropeza-Aburto, Araceli; Cruz-Ramírez, Alfredo; Acevedo-Hernández, Gustavo J.; Pérez-Torres, Claudia-Anahí; Caballero-Pérez, Juan; Herrera-Estrella, Luis

2012-01-01

Plants have evolved a plethora of responses to cope with phosphate (Pi) deficiency, including the transcriptional activation of a large set of genes. Among Pi-responsive genes, the expression of the Arabidopsis phospholipase DZ2 (PLDZ2) is activated to participate in the degradation of phospholipids in roots in order to release Pi to support other cellular activities. A deletion analysis was performed to identify the regions determining the strength, tissue-specific expression, and Pi responsiveness of this regulatory region. This study also reports the identification and characterization of a transcriptional enhancer element that is present in the PLDZ2 promoter and able to confer Pi responsiveness to a minimal, inactive 35S promoter. This enhancer also shares the cytokinin and sucrose responsive properties observed for the intact PLDZ2 promoter. The EZ2 element contains two P1BS motifs, each of which is the DNA binding site of transcription factor PHR1. Mutation analysis showed that the P1BS motifs present in EZ2 are necessary but not sufficient for the enhancer function, revealing the importance of adjacent sequences. The structural organization of EZ2 is conserved in the orthologous genes of at least eight families of rosids, suggesting that architectural features such as the distance between the two P1BS motifs are also important for the regulatory properties of this enhancer element. PMID:22210906

Genome-wide analysis identifies chickpea (Cicer arietinum) heat stress transcription factors (Hsfs) responsive to heat stress at the pod development stage.

PubMed

Chidambaranathan, Parameswaran; Jagannadham, Prasanth Tej Kumar; Satheesh, Viswanathan; Kohli, Deshika; Basavarajappa, Santosh Halasabala; Chellapilla, Bharadwaj; Kumar, Jitendra; Jain, Pradeep Kumar; Srinivasan, R

2018-05-01

The heat stress transcription factors (Hsfs) play a prominent role in thermotolerance and eliciting the heat stress response in plants. Identification and expression analysis of Hsfs gene family members in chickpea would provide valuable information on heat stress responsive Hsfs. A genome-wide analysis of Hsfs gene family resulted in the identification of 22 Hsf genes in chickpea in both desi and kabuli genome. Phylogenetic analysis distinctly separated 12 A, 9 B, and 1 C class Hsfs, respectively. An analysis of cis-regulatory elements in the upstream region of the genes identified many stress responsive elements such as heat stress elements (HSE), abscisic acid responsive element (ABRE) etc. In silico expression analysis showed nine and three Hsfs were also expressed in drought and salinity stresses, respectively. Q-PCR expression analysis of Hsfs under heat stress at pod development and at 15 days old seedling stage showed that CarHsfA2, A6, and B2 were significantly upregulated in both the stages of crop growth and other four Hsfs (CarHsfA2, A6a, A6c, B2a) showed early transcriptional upregulation for heat stress at seedling stage of chickpea. These subclasses of Hsfs identified in this study can be further evaluated as candidate genes in the characterization of heat stress response in chickpea.

Transient conduction-radiation analysis of an absolute active cavity radiometer using finite elements

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Kowsary, F.; Tira, N.; Gardiner, B. D.

1987-01-01

A NASA-developed finite element-based model of a generic active cavity radiometer (ACR) has been developed in order to study the dependence on operating temperature of the closed-loop and open-loop transient response of the instrument. Transient conduction within the sensing element is explored, and the transient temperature distribution resulting from the application of a time-varying radiative boundary condition is calculated. The results verify the prediction that operation of an ACR at cryogenic temperatures results in large gains in frequency response.

Prediction of response of aircraft panels subjected to acoustic and thermal loads

NASA Technical Reports Server (NTRS)

Mei, Chuh

1992-01-01

The primary effort of this research project has been focused on the development of analytical methods for the prediction of random response of structural panels subjected to combined and intense acoustic and thermal loads. The accomplishments on various acoustic fatigue research activities are described first, then followed by publications and theses. Topics covered include: transverse shear deformation; finite element models of vibrating composite laminates; large deflection vibration modeling; finite element analysis of thermal buckling; and prediction of three dimensional duct using boundary element method.

Stacked switchable element and diode combination with a low breakdown switchable element

DOEpatents

Wang, Qi [Littleton, CO; Ward, James Scott [Englewood, CO; Hu, Jian [Englewood, CO; Branz, Howard M [Boulder, CO

2012-06-19

A device (10) comprises a semiconductor diode (12) and a switchable element (14) positioned in stacked adjacent relationship. The semiconductor diode (12) and the switchable element (14) are electrically connected in series with one another. The switchable element (14) is switchable from a low-conductance state to a high-conductance state in response to the application of a low-density forming current and/or a low voltage.

An ethylene-responsive enhancer element is involved in the senescence-related expression of the carnation glutathione-S-transferase (GST1) gene.

PubMed

Itzhaki, H; Maxson, J M; Woodson, W R

1994-09-13

The increased production of ethylene during carnation petal senescence regulates the transcription of the GST1 gene encoding a subunit of glutathione-S-transferase. We have investigated the molecular basis for this ethylene-responsive transcription by examining the cis elements and trans-acting factors involved in the expression of the GST1 gene. Transient expression assays following delivery of GST1 5' flanking DNA fused to a beta-glucuronidase receptor gene were used to functionally define sequences responsible for ethylene-responsive expression. Deletion analysis of the 5' flanking sequences of GST1 identified a single positive regulatory element of 197 bp between -667 and -470 necessary for ethylene-responsive expression. The sequences within this ethylene-responsive region were further localized to 126 bp between -596 and -470. The ethylene-responsive element (ERE) within this region conferred ethylene-regulated expression upon a minimal cauliflower mosaic virus-35S TATA-box promoter in an orientation-independent manner. Gel electrophoresis mobility-shift assays and DNase I footprinting were used to identify proteins that bind to sequences within the ERE. Nuclear proteins from carnation petals were shown to specifically interact with the 126-bp ERE and the presence and binding of these proteins were independent of ethylene or petal senescence. DNase I footprinting defined DNA sequences between -510 and -488 within the ERE specifically protected by bound protein. An 8-bp sequence (ATTTCAAA) within the protected region shares significant homology with promoter sequences required for ethylene responsiveness from the tomato fruit-ripening E4 gene.

De Novo Regulatory Motif Discovery Identifies Significant Motifs in Promoters of Five Classes of Plant Dehydrin Genes.

PubMed

Zolotarov, Yevgen; Strömvik, Martina

2015-01-01

Plants accumulate dehydrins in response to osmotic stresses. Dehydrins are divided into five different classes, which are thought to be regulated in different manners. To better understand differences in transcriptional regulation of the five dehydrin classes, de novo motif discovery was performed on 350 dehydrin promoter sequences from a total of 51 plant genomes. Overrepresented motifs were identified in the promoters of five dehydrin classes. The Kn dehydrin promoters contain motifs linked with meristem specific expression, as well as motifs linked with cold/dehydration and abscisic acid response. KS dehydrin promoters contain a motif with a GATA core. SKn and YnSKn dehydrin promoters contain motifs that match elements connected with cold/dehydration, abscisic acid and light response. YnKn dehydrin promoters contain motifs that match abscisic acid and light response elements, but not cold/dehydration response elements. Conserved promoter motifs are present in the dehydrin classes and across different plant lineages, indicating that dehydrin gene regulation is likely also conserved.

Application of the Spectral Element Method to Interior Noise Problems

NASA Technical Reports Server (NTRS)

Doyle, James F.

1998-01-01

The primary effort of this research project was focused the development of analytical methods for the accurate prediction of structural acoustic noise and response. Of particular interest was the development of curved frame and shell spectral elements for the efficient computational of structural response and of schemes to match this to the surrounding fluid.

45 CFR Appendix E to Part 1355 - Data Standards

Code of Federal Regulations, 2010 CFR

2010-10-01

... of most recent periodic, review. 06 Child's date of birth. 07 Child's sex. 08 Child's race. 09 Child... responses to the question. For example, if the acceptable response to the element, Sex of the Adoptive Child.... Element name 05 Child's date of birth. 06 Child's sex. 07 Child's race. 08 Is the child of Hispanic or...

45 CFR Appendix E to Part 1355 - Data Standards

Code of Federal Regulations, 2011 CFR

2011-10-01

... of most recent periodic, review. 06 Child's date of birth. 07 Child's sex. 08 Child's race. 09 Child... responses to the question. For example, if the acceptable response to the element, Sex of the Adoptive Child.... Element name 05 Child's date of birth. 06 Child's sex. 07 Child's race. 08 Is the child of Hispanic or...

[Construction of a general AAV vector regulated by minimal and artificial hypoxic-responsive element].

PubMed

Nie, Xiao-wei; Sun, Li-jun; Hao, Yue-wen; Yang, Guang-xiao; Wang, Quan-ying

2011-03-01

To synthesize the minimal and artificial HRE, and to insert it into the anterior extremity of CMV promoter of a AAV plasmid, and then to construct the AAV regulated by hypoxic-responsive element which was introduced into 293 cell by method of Ca3(PO4)2 using three plasmids. Thus obtaining the adenoassociated virus vector regulated by hypoxic-responsive element was possibly used for gene therapy in ischemia angiocardiopathy and cerebrovascular disease. Artificially synthesize the 36 bp nucleotide sequences of four connection in series HIF-binding sites A/GCGTG(4×HBS)and a 35 bp nucleotide sequences spacing inserted into anterior extremity of CMV promoter TATA Box, then amplified by PCR. The cDNA fragment was confirmed to be right by DNA sequencing. Molecular biology routine method was used to construct a AAV vector regulated by minimal hypoxic-responsive element after the normal CMV promoter in AAV vector was replaced by the CMV promoter included minimal hypoxic-responsive element. Then, NT4-6His-PR39 fusogenic peptide was inserted into MCS of the plasmid, the recombinant AAV vector was obtained by three plasmid co-transfection in 293 cells, in which we can also investigate the expression of 6×His using immunochemistry in hypoxia environment. Artificial HRE was inserted into anterior extremity of CMV promoter and there was a correct spacing between the HRE and the TATA-box. The DNA sequencing and restriction enzyme digestion results indicated that the AAV regulated by hypoxic-responsive element was successfully constructed. Compared to the control group, the expressions of 6×His was significantly increased in the experimental groups in hypoxia environment, which confirmed that the AAV effectually regulated by the minimal HRE was inserted into anterior extremity of CMV promoter. The HRE is inserted into anterior extremity of CMV promoter to lack incision enzyme recognition site by PCR. And eukaryotic expression vector regulated by hypoxic-responsive is constructed. The AAV effectually regulated by the minimal HRE inserted into anterior extremity of CMV promoter. The vector is successfully constructed and it has important theoretical and practical value in the synteresis and therapy of ischemia angiocardiopathy and cerebrovascular disease.

Magnetic filtration process, magnetic filtering material, and methods of forming magnetic filtering material

DOEpatents

Taboada-Serrano, Patricia; Tsouris, Constantino; Contescu, Cristian I; McFarlane, Joanna

2013-10-08

The present invention provides magnetically responsive activated carbon, and a method of forming magnetically responsive activated carbon. The method of forming magnetically responsive activated carbon typically includes providing activated carbon in a solution containing ions of ferrite forming elements, wherein at least one of the ferrite forming elements has an oxidation state of +3 and at least a second of the ferrite forming elements has an oxidation state of +2, and increasing pH of the solution to precipitate particles of ferrite that bond to the activated carbon, wherein the activated carbon having the ferrite particles bonded thereto have a positive magnetic susceptibility. The present invention also provides a method of filtering waste water using magnetic activated carbon.

Similar Intracellular Location and Stimulus Reactivity, but Differential Mobility of Tailless (Vicia faba) and Tailed Forisomes (Phaseolus vulgaris) in Intact Sieve Tubes.

PubMed

Furch, Alexandra C U; Buxa, Stefanie V; van Bel, Aart J E

2015-01-01

Sieve elements of legumes contain forisomes-fusiform protein bodies that are responsible for sieve-tube occlusion in response to damage or wound signals. Earlier work described the existence of tailless and tailed forisomes. This study intended to quantify and compare location and position of tailless (in Vicia faba) and tailed (in Phaseolus vulgaris) forisomes inside sieve elements and to assess their reactivity and potential mobility in response to a remote stimulus. Location (distribution within sieve elements) and position (forisome tip contacts) of more than altogether 2000 forisomes were screened in 500 intact plants by laser scanning confocal microscopy in the transmission mode. Furthermore, we studied the dispersion of forisomes at different locations in different positions and their positional behaviour in response to distant heat shocks. Forisome distribution turned out to be species-specific, whereas forisome positions at various locations were largely similar in bushbean (Phaseolus) and broadbean (Vicia). In general, the tailless forisomes had higher dispersion rates in response to heat shocks than the tailed forisomes and forisomes at the downstream (basal) end dispersed more frequently than those at the upstream end (apical). In contrast to the tailless forisomes that only oscillate in response to heat shocks, downstream-located tailed forisomes can cover considerable distances within sieve elements. This displacement was prevented by gentle rubbing of the leaf (priming) before the heat shock. Movement of these forisomes was also prohibited by Latrunculin A, an inhibitor of actin polymerization. The apparently active mobility of tailed forisomes gives credence to the idea that at least the latter forisomes are not free-floating, but connected to other sieve-element structures.

Similar Intracellular Location and Stimulus Reactivity, but Differential Mobility of Tailless (Vicia faba) and Tailed Forisomes (Phaseolus vulgaris) in Intact Sieve Tubes

PubMed Central

van Bel, Aart J. E.

2015-01-01

Sieve elements of legumes contain forisomes—fusiform protein bodies that are responsible for sieve-tube occlusion in response to damage or wound signals. Earlier work described the existence of tailless and tailed forisomes. This study intended to quantify and compare location and position of tailless (in Vicia faba) and tailed (in Phaseolus vulgaris) forisomes inside sieve elements and to assess their reactivity and potential mobility in response to a remote stimulus. Location (distribution within sieve elements) and position (forisome tip contacts) of more than altogether 2000 forisomes were screened in 500 intact plants by laser scanning confocal microscopy in the transmission mode. Furthermore, we studied the dispersion of forisomes at different locations in different positions and their positional behaviour in response to distant heat shocks. Forisome distribution turned out to be species-specific, whereas forisome positions at various locations were largely similar in bushbean (Phaseolus) and broadbean (Vicia). In general, the tailless forisomes had higher dispersion rates in response to heat shocks than the tailed forisomes and forisomes at the downstream (basal) end dispersed more frequently than those at the upstream end (apical). In contrast to the tailless forisomes that only oscillate in response to heat shocks, downstream-located tailed forisomes can cover considerable distances within sieve elements. This displacement was prevented by gentle rubbing of the leaf (priming) before the heat shock. Movement of these forisomes was also prohibited by Latrunculin A, an inhibitor of actin polymerization. The apparently active mobility of tailed forisomes gives credence to the idea that at least the latter forisomes are not free-floating, but connected to other sieve-element structures. PMID:26624625

Transcriptomic analysis of rice aleurone cells identified a novel abscisic acid response element.

PubMed

Watanabe, Kenneth A; Homayouni, Arielle; Gu, Lingkun; Huang, Kuan-Ying; Ho, Tuan-Hua David; Shen, Qingxi J

2017-09-01

Seeds serve as a great model to study plant responses to drought stress, which is largely mediated by abscisic acid (ABA). The ABA responsive element (ABRE) is a key cis-regulatory element in ABA signalling. However, its consensus sequence (ACGTG(G/T)C) is present in the promoters of only about 40% of ABA-induced genes in rice aleurone cells, suggesting other ABREs may exist. To identify novel ABREs, RNA sequencing was performed on aleurone cells of rice seeds treated with 20 μM ABA. Gibbs sampling was used to identify enriched elements, and particle bombardment-mediated transient expression studies were performed to verify the function. Gene ontology analysis was performed to predict the roles of genes containing the novel ABREs. This study revealed 2443 ABA-inducible genes and a novel ABRE, designated as ABREN, which was experimentally verified to mediate ABA signalling in rice aleurone cells. Many of the ABREN-containing genes are predicted to be involved in stress responses and transcription. Analysis of other species suggests that the ABREN may be monocot specific. This study also revealed interesting expression patterns of genes involved in ABA metabolism and signalling. Collectively, this study advanced our understanding of diverse cis-regulatory sequences and the transcriptomes underlying ABA responses in rice aleurone cells. © 2017 John Wiley & Sons Ltd.

cis- and trans-acting elements of the estrogen-regulated vitellogenin gene B1 of Xenopus laevis.

PubMed

Wahli, W; Martinez, E; Corthésy, B; Cardinaux, J R

1989-01-01

Vitellogenin genes are expressed under strict estrogen control in the liver of female oviparous vertebrates. Gene transfer experiments using estrogen-responsive cells have shown that the 13 bp perfect palindromic element GGTCACTGTGACC found upstream of the Xenopus laevis vitellogenin gene A2 promoter mediates hormonal stimulation and thus, was called the estrogen-responsive element (ERE). In the Xenopus vitellogenin genes B1 and B2 there are two closely adjacent EREs with one or more base substitutions when compared to the consensus ERE GGTCANNNTGACC. On their own, these degenerated elements have only a low or no regulatory capacity at all but act together synergistically to form an estrogen-responsive unit (ERU) with the same strength as the perfect palindromic 13 bp element. Analysis of estrogen receptor binding to the gene B1 ERU revealed a cooperative interaction of receptor dimers to the two adjacent imperfect EREs which most likely explains the synergistic stimulation observed in vivo. Furthermore, a promoter activator element located between positions --113 and --42 of the gene B1 and functional in the human MCF-7 and the Xenopus B3.2 cells has been identified and shown to be involved in the high level of induced transcription activity when the ERE is placed at a distance from the promoter. Finally, a hormone-controlled in vitro transcription system derived from Xenopus liver nuclear extracts was exploited to characterize two additional novel cis-acting elements within the vitellogenin gene B1 promoter. One of them, a negative regulatory element (NRE), is responsible for repression of promoter activity in the absence of hormone. The second is related to the NF-I binding site and is required, together with the ERE, to mediate hormonal induction. Moreover, we detected three trans-acting activities in Xenopus liver nuclear extracts that interact with these regions and demonstrated that they participate in the regulation of the expression of the vitellogenin promoter in vitro.

A 20 bp cis-acting element is both necessary and sufficient to mediate elicitor response of a maize PRms gene.

PubMed

Raventós, D; Jensen, A B; Rask, M B; Casacuberta, J M; Mundy, J; San Segundo, B

1995-01-01

Transient gene expression assays in barley aleurone protoplasts were used to identify a cis-regulatory element involved in the elicitor-responsive expression of the maize PRms gene. Analysis of transcriptional fusions between PRms 5' upstream sequences and a chloramphenicol acetyltransferase reporter gene, as well as chimeric promoters containing PRms promoter fragments or repeated oligonucleotides fused to a minimal promoter, delineated a 20 bp sequence which functioned as an elicitor-response element (ERE). This sequence contains a motif (-246 AATTGACC) similar to sequences found in promoters of other pathogen-responsive genes. The analysis also indicated that an enhancing sequence(s) between -397 and -296 is required for full PRms activation by elicitors. The protein kinase inhibitor staurosporine was found to completely block the transcriptional activation induced by elicitors. These data indicate that protein phosphorylation is involved in the signal transduction pathway leading to PRms expression.

The non-linear response of a muscle in transverse compression: assessment of geometry influence using a finite element model.

PubMed

Gras, Laure-Lise; Mitton, David; Crevier-Denoix, Nathalie; Laporte, Sébastien

2012-01-01

Most recent finite element models that represent muscles are generic or subject-specific models that use complex, constitutive laws. Identification of the parameters of such complex, constitutive laws could be an important limit for subject-specific approaches. The aim of this study was to assess the possibility of modelling muscle behaviour in compression with a parametric model and a simple, constitutive law. A quasi-static compression test was performed on the muscles of dogs. A parametric finite element model was designed using a linear, elastic, constitutive law. A multi-variate analysis was performed to assess the effects of geometry on muscle response. An inverse method was used to define Young's modulus. The non-linear response of the muscles was obtained using a subject-specific geometry and a linear elastic law. Thus, a simple muscle model can be used to have a bio-faithful, biomechanical response.

Partitioning strategy for efficient nonlinear finite element dynamic analysis on multiprocessor computers

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Peters, Jeanne M.

1989-01-01

A computational procedure is presented for the nonlinear dynamic analysis of unsymmetric structures on vector multiprocessor systems. The procedure is based on a novel hierarchical partitioning strategy in which the response of the unsymmetric and antisymmetric response vectors (modes), each obtained by using only a fraction of the degrees of freedom of the original finite element model. The three key elements of the procedure which result in high degree of concurrency throughout the solution process are: (1) mixed (or primitive variable) formulation with independent shape functions for the different fields; (2) operator splitting or restructuring of the discrete equations at each time step to delineate the symmetric and antisymmetric vectors constituting the response; and (3) two level iterative process for generating the response of the structure. An assessment is made of the effectiveness of the procedure on the CRAY X-MP/4 computers.

Load responsive hydrodynamic bearing

DOEpatents

Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

2002-01-01

A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

Four regulatory elements in the human c-fos promoter mediate transactivation by HTLV-1 Tax protein.

PubMed

Alexandre, C; Verrier, B

1991-04-01

Expression of the human c-fos proto-oncogene is activated in trans by the Tax protein encoded by human T-cell leukemia virus type-1 (HTLV-1). Indeed, we show here that a HeLa clone stably transfected by Tax expresses Fos at a high level. We also show that multiple elements of the human c-fos promoter, i.e. the v-sis conditioned medium inducible element (SIE), the dyad symmetry element (DSE) necessary for growth factor induction, the octanucleotide direct repeat element (DR), and the cyclic AMP response element (CRE) centred at -60, can all mediate Tax transactivation. In the DSE, the 10bp central core that binds the serum response factor (SRF) is, by itself, sufficient to mediate Tax transactivation. Moreover, a CRE-binding protein is involved in Tax activation through the CRE-60 element. Since Fos is a transregulator of cellular genes, our results suggest that the oncoprotein plays a crucial role in T-cell transformation by HTLV-1 in conjunction with other Tax-inducible genes.

Identification of cis-acting regulatory elements in the human oxytocin gene promoter.

PubMed

Richard, S; Zingg, H H

1991-12-01

The expression of hormone-inducible genes is determined by the interaction of trans-acting factors with hormone-inducible elements and elements mediating basal and cell-specific expression. We have shown earlier that the gene encoding the hypothalamic nonapeptide oxytocin (OT) is under the control of an estrogen response element (ERE). The present study was aimed at identifying cis-acting elements mediating basal expression of the OT gene. A construct containing sequences -381 to +36 of the human OT gene was linked to a reporter gene and transiently transfected into a series of neuronal and nonneuronal cell lines. Expression of this construct was cell specific: it was highest in the neuroblastoma-derived cell line, Neuro-2a, and lowest in NIH 3T3 and JEG-3 cells. By 5' deletion analysis, we determined that a segment from -49 to +36 was capable of mediating cells-pecific promoter activity. Within this segment, we identified three proximal promoter elements (PPE-1, PPE-2, and PPE-3) that are each required for promoter activity. Most notably, mutation of a conserved purine-rich element (GAGAGA) contained within PPE-2 leads to a 10-fold decrease in promoter strength. Gel mobility shift analysis with three different double-stranded oligonucleotides demonstrated that each proximal promoter element binds distinct nuclear factors. In each case, only the homologous oligonucleotide, but neither of the oligonucleotides corresponding to adjacent elements, was able to act as a competitor. Thus, a different set of factors appears to bind independently to each element. By reinserting the homologous ERE or a heterologous glucocorticoid response element upstream of intact or altered proximal promoter segments we determined that removal or mutation of proximal promoter elements decreases basal expression, but does not abrogate the hormone responsiveness of the promoter. In conclusion, these results indicate that an important component of the transcriptional activity of the OT promoter resides in a small region extending only 50 bases upstream of the cap site and that this activity is the result of a cooperative interaction of at least three distinct proximal promoter elements.

Techniques for forced response involving discrete nonlinearities. I - Theory. II - Applications

NASA Astrophysics Data System (ADS)

Avitabile, Peter; Callahan, John O.

Several new techniques developed for the forced response analysis of systems containing discrete nonlinear connection elements are presented and compared to the traditional methods. In particular, the techniques examined are the Equivalent Reduced Model Technique (ERMT), Modal Modification Response Technique (MMRT), and Component Element Method (CEM). The general theory of the techniques is presented, and applications are discussed with particular reference to the beam nonlinear system model using ERMT, MMRT, and CEM; frame nonlinear response using the three techniques; and comparison of the results obtained by using the ERMT, MMRT, and CEM models.

STARS: A general-purpose finite element computer program for analysis of engineering structures

NASA Technical Reports Server (NTRS)

Gupta, K. K.

1984-01-01

STARS (Structural Analysis Routines) is primarily an interactive, graphics-oriented, finite-element computer program for analyzing the static, stability, free vibration, and dynamic responses of damped and undamped structures, including rotating systems. The element library consists of one-dimensional (1-D) line elements, two-dimensional (2-D) triangular and quadrilateral shell elements, and three-dimensional (3-D) tetrahedral and hexahedral solid elements. These elements enable the solution of structural problems that include truss, beam, space frame, plane, plate, shell, and solid structures, or any combination thereof. Zero, finite, and interdependent deflection boundary conditions can be implemented by the program. The associated dynamic response analysis capability provides for initial deformation and velocity inputs, whereas the transient excitation may be either forces or accelerations. An effective in-core or out-of-core solution strategy is automatically employed by the program, depending on the size of the problem. Data input may be at random within a data set, and the program offers certain automatic data-generation features. Input data are formatted as an optimal combination of free and fixed formats. Interactive graphics capabilities enable convenient display of nodal deformations, mode shapes, and element stresses.

A Full Dynamic Compound Inverse Method for output-only element-level system identification and input estimation from earthquake response signals

NASA Astrophysics Data System (ADS)

Pioldi, Fabio; Rizzi, Egidio

2016-08-01

This paper proposes a new output-only element-level system identification and input estimation technique, towards the simultaneous identification of modal parameters, input excitation time history and structural features at the element-level by adopting earthquake-induced structural response signals. The method, named Full Dynamic Compound Inverse Method (FDCIM), releases strong assumptions of earlier element-level techniques, by working with a two-stage iterative algorithm. Jointly, a Statistical Average technique, a modification process and a parameter projection strategy are adopted at each stage to achieve stronger convergence for the identified estimates. The proposed method works in a deterministic way and is completely developed in State-Space form. Further, it does not require continuous- to discrete-time transformations and does not depend on initialization conditions. Synthetic earthquake-induced response signals from different shear-type buildings are generated to validate the implemented procedure, also with noise-corrupted cases. The achieved results provide a necessary condition to demonstrate the effectiveness of the proposed identification method.

A Mixed Multi-Field Finite Element Formulation for Thermopiezoelectric Composite Shells

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun; Saravanos, Dimitris A.

1999-01-01

Analytical formulations are presented which account for the coupled mechanical, electrical, and thermal response of piezoelectric composite shell structures. A new mixed multi-field laminate theory is developed which combines "single layer" assumptions for the displacements along with layerwise fields for the electric potential and temperature. This laminate theory is formulated using curvilinear coordinates and is based on the principles of linear thermopiezoelectricity. The mechanics have the inherent capability to explicitly model both the active and sensory responses of piezoelectric composite shells in thermal environment. Finite element equations are derived and implemented for an eight-noded shell element. Numerical studies are conducted to investigate both the sensory and active responses of piezoelectric composite shell structures subjected to thermal loads. Results for a cantilevered plate with an attached piezoelectric layer are com- pared with corresponding results from a commercial finite element code and a previously developed program. Additional studies are conducted on a cylindrical shell with an attached piezoelectric layer to demonstrate capabilities to achieve thermal shape control on curved piezoelectric structures.

The Penn State Safety Floor: Part I--Design parameters associated with walking deflections.

PubMed

Casalena, J A; Ovaert, T C; Cavanagh, P R; Streit, D A

1998-08-01

A new flooring system has been developed to reduce peak impact forces to the hips when humans fall. The new safety floor is designed to remain relatively rigid under normal walking conditions, but to deform elastically when impacted during a fall. Design objectives included minimizing peak force experienced by the femur during a fall-induced impact, while maintaining a maximum of 2 mm of floor deflection during walking. Finite Element Models (FEMs) were developed to capture the complex dynamics of impact response between two deformable bodies. Validation of the finite element models included analytical calculations of theoretical buckling column response, experimental quasi-static loading of full-scale flooring prototypes, and flooring response during walking trials. Finite Element Method results compared well with theoretical and experimental data. Both finite element and experimental data suggest that the proposed safety floor can effectively meet the design goal of 2 mm maximum deflection during walking, while effectively reducing impact forces during a fall.

Regulation of the intronic promoter of rat estrogen receptor alpha gene, responsible for truncated estrogen receptor product-1 expression.

PubMed

Schausi, Diane; Tiffoche, Christophe; Thieulant, Marie-Lise

2003-07-01

We have characterized the intronic promoter of the rat estrogen receptor (ER) alpha gene, responsible for the lactotrope-specific truncated ER product (TERP)-1 isoform expression. Transcriptional regulation was investigated by transient transfections using 5'-deletion constructs. TERP promoter constructs were highly active in MMQ cells, a pure lactotrope cell line, whereas a low basal activity was detected in alphaT3-1 gonadotrope cells or in COS-7 monkey kidney cells. Serial deletion analysis revealed that 1) a minimal -693-bp region encompassing the TATA box is sufficient to allow lactotrope-specific expression; 2) the promoter contains strong positive cis-acting elements both in the distal and proximal regions, and 3) the region spanning the -1698/-1194 region includes repressor elements. Transient transfection studies, EMSAs, and gel shifts demonstrated that estrogen activates the TERP promoter via an estrogen-responsive element (ERE1) located within the proximal region. Mutation of ERE1 site completely abolishes the estradiol-dependent transcription, indicating that ERE1 site is sufficient to confer estrogen responsiveness to TERP promoter. In addition, ERalpha action was synergized by transfection of the pituitary-specific factor Pit-1. EMSAs showed that a single Pit-1 DNA binding element in the vicinity of the TATA box is sufficient to confer response by the TERP promoter. In conclusion, we demonstrated, for the first time, that TERP promoter regulation involves ERE and Pit-1 cis-elements and corresponding trans-acting factors, which could play a role in the physiological changes that occur in TERP-1 transcription in lactotrope cells.

Surveying DNA Elements within Functional Genes of Heterocyst-Forming Cyanobacteria

PubMed Central

Hilton, Jason A.; Meeks, John C.; Zehr, Jonathan P.

2016-01-01

Some cyanobacteria are capable of differentiating a variety of cell types in response to environmental factors. For instance, in low nitrogen conditions, some cyanobacteria form heterocysts, which are specialized for N2 fixation. Many heterocyst-forming cyanobacteria have DNA elements interrupting key N2 fixation genes, elements that are excised during heterocyst differentiation. While the mechanism for the excision of the element has been well-studied, many questions remain regarding the introduction of the elements into the cyanobacterial lineage and whether they have been retained ever since or have been lost and reintroduced. To examine the evolutionary relationships and possible function of DNA sequences that interrupt genes of heterocyst-forming cyanobacteria, we identified and compared 101 interruption element sequences within genes from 38 heterocyst-forming cyanobacterial genomes. The interruption element lengths ranged from about 1 kb (the minimum able to encode the recombinase responsible for element excision), up to nearly 1 Mb. The recombinase gene sequences served as genetic markers that were common across the interruption elements and were used to track element evolution. Elements were found that interrupted 22 different orthologs, only five of which had been previously observed to be interrupted by an element. Most of the newly identified interrupted orthologs encode proteins that have been shown to have heterocyst-specific activity. However, the presence of interruption elements within genes with no known role in N2 fixation, as well as in three non-heterocyst-forming cyanobacteria, indicates that the processes that trigger the excision of elements may not be limited to heterocyst development or that the elements move randomly within genomes. This comprehensive analysis provides the framework to study the history and behavior of these unique sequences, and offers new insight regarding the frequency and persistence of interruption elements in heterocyst-forming cyanobacteria. PMID:27206019

Surveying DNA Elements within Functional Genes of Heterocyst-Forming Cyanobacteria.

PubMed

Hilton, Jason A; Meeks, John C; Zehr, Jonathan P

2016-01-01

Some cyanobacteria are capable of differentiating a variety of cell types in response to environmental factors. For instance, in low nitrogen conditions, some cyanobacteria form heterocysts, which are specialized for N2 fixation. Many heterocyst-forming cyanobacteria have DNA elements interrupting key N2 fixation genes, elements that are excised during heterocyst differentiation. While the mechanism for the excision of the element has been well-studied, many questions remain regarding the introduction of the elements into the cyanobacterial lineage and whether they have been retained ever since or have been lost and reintroduced. To examine the evolutionary relationships and possible function of DNA sequences that interrupt genes of heterocyst-forming cyanobacteria, we identified and compared 101 interruption element sequences within genes from 38 heterocyst-forming cyanobacterial genomes. The interruption element lengths ranged from about 1 kb (the minimum able to encode the recombinase responsible for element excision), up to nearly 1 Mb. The recombinase gene sequences served as genetic markers that were common across the interruption elements and were used to track element evolution. Elements were found that interrupted 22 different orthologs, only five of which had been previously observed to be interrupted by an element. Most of the newly identified interrupted orthologs encode proteins that have been shown to have heterocyst-specific activity. However, the presence of interruption elements within genes with no known role in N2 fixation, as well as in three non-heterocyst-forming cyanobacteria, indicates that the processes that trigger the excision of elements may not be limited to heterocyst development or that the elements move randomly within genomes. This comprehensive analysis provides the framework to study the history and behavior of these unique sequences, and offers new insight regarding the frequency and persistence of interruption elements in heterocyst-forming cyanobacteria.

The Use of Sparse Direct Solver in Vector Finite Element Modeling for Calculating Two Dimensional (2-D) Magnetotelluric Responses in Transverse Electric (TE) Mode

NASA Astrophysics Data System (ADS)

Yihaa Roodhiyah, Lisa’; Tjong, Tiffany; Nurhasan; Sutarno, D.

2018-04-01

The late research, linear matrices of vector finite element in two dimensional(2-D) magnetotelluric (MT) responses modeling was solved by non-sparse direct solver in TE mode. Nevertheless, there is some weakness which have to be improved especially accuracy in the low frequency (10-3 Hz-10-5 Hz) which is not achieved yet and high cost computation in dense mesh. In this work, the solver which is used is sparse direct solver instead of non-sparse direct solverto overcome the weaknesses of solving linear matrices of vector finite element metod using non-sparse direct solver. Sparse direct solver will be advantageous in solving linear matrices of vector finite element method because of the matrix properties which is symmetrical and sparse. The validation of sparse direct solver in solving linear matrices of vector finite element has been done for a homogen half-space model and vertical contact model by analytical solution. Thevalidation result of sparse direct solver in solving linear matrices of vector finite element shows that sparse direct solver is more stable than non-sparse direct solver in computing linear problem of vector finite element method especially in low frequency. In the end, the accuracy of 2D MT responses modelling in low frequency (10-3 Hz-10-5 Hz) has been reached out under the efficient allocation memory of array and less computational time consuming.

Long-Term Memory for Place Learning Is Facilitated by Expression of cAMP Response Element-Binding Protein in the Dorsal Hippocampus

ERIC Educational Resources Information Center

Brightwell, Jennifer J.; Smith, Clayton A.; Neve, Rachael L.; Colombo, Paul J.

2007-01-01

Extensive research has shown that the hippocampus is necessary for consolidation of long-term spatial memory in rodents. We reported previously that rats using a place strategy to solve a cross maze task showed sustained phosphorylation of hippocampus cyclic AMP response element-binding protein (CREB), a transcription factor implicated in…

Transcriptional activation of rat creatine kinase B by 17beta-estradiol in MCF-7 cells involves an estrogen responsive element and GC-rich sites.

PubMed

Wang, F; Samudio, I; Safe, S

2001-01-01

The rat creatine kinase B (CKB) gene is induced by estrogen in the uterus, and constructs containing rat CKB gene promoter inserts are highly estrogen-responsive in cell culture. Analysis of the upstream -568 to -523 region of the promoter in HeLa cells has identified an imperfect palindromic estrogen response element (ERE) that is required for hormone inducibility. Analysis of the CKB gene promoter in MCF-7 breast cancer cells confirmed that pCKB7 (containing the -568 to -523 promoter insert) was estrogen-responsive in transient transfection studies. However, mutation and deletion analysis of this region of the promoter showed that two GC-rich sites and the concensus ERE were functional cis-elements that bound estrogen receptor alpha (ERalpha)/Sp1 and ERalpha proteins, respectively. The role of these elements was confirmed in gel mobility shift and chromatin immunoprecipitation assays and transfection studies in MDA-MB-231 and Schneider Drosophila SL-2 cells. These results show that transcriptional activation of CKB by estrogen is dependent, in part, on ERalpha/Sp1 action which is cell context-dependent. Copyright 2001 Wiley-Liss, Inc.

Numerical Modeling of 3D Seismic Wave Propagation around Yogyakarta, the Southern Part of Central Java, Indonesia, Using Spectral-Element Method on MPI-GPU Cluster

NASA Astrophysics Data System (ADS)

Sudarmaji; Rudianto, Indra; Eka Nurcahya, Budi

2018-04-01

A strong tectonic earthquake with a magnitude of 5.9 Richter scale has been occurred in Yogyakarta and Central Java on May 26, 2006. The earthquake has caused severe damage in Yogyakarta and the southern part of Central Java, Indonesia. The understanding of seismic response of earthquake among ground shaking and the level of building damage is important. We present numerical modeling of 3D seismic wave propagation around Yogyakarta and the southern part of Central Java using spectral-element method on MPI-GPU (Graphics Processing Unit) computer cluster to observe its seismic response due to the earthquake. The homogeneous 3D realistic model is generated with detailed topography surface. The influences of free surface topography and layer discontinuity of the 3D model among the seismic response are observed. The seismic wave field is discretized using spectral-element method. The spectral-element method is solved on a mesh of hexahedral elements that is adapted to the free surface topography and the internal discontinuity of the model. To increase the data processing capabilities, the simulation is performed on a GPU cluster with implementation of MPI (Message Passing Interface).

Dynamic responses of graphite/epoxy laminated beam to impact of elastic spheres

NASA Technical Reports Server (NTRS)

Sun, C. T.; Wang, T.

1982-01-01

Wave propagation in 90/45/90/-45/902s and 0/45/0/-45/02s laminates of a graphite/epoxy composite due to impact of a steel ball was investigated experimentally and also by using a high order beam finite element. Dynamic strain responses at several locations were obtained using strain gages. The finite element program which incorporated statically determined contact laws was employed to calculate the contact force history as well as the target beam dynamic deformation. The comparison of the finite element solutions with the experimental data indicated that the static contact laws for loading and unloading (developed under this grant) are adequate for the dynamic impact analysis. It was found that for the 0/45/0/-45/02s laminate which has a much larger longitudinal bending rigidity, the use of beam finite elements is not suitable and plate finite element should be used instead.

Analysis of resonance response performance of C-band antenna using parasitic element.

PubMed

Zaman, M R; Islam, M T; Misran, N; Mandeep, J S

2014-01-01

Analysis of the resonance response improvement of a planar C-band (4-8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency.

Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus.

PubMed Central

Marciniak, R A; Garcia-Blanco, M A; Sharp, P A

1990-01-01

Human immunodeficiency virus type 1 RNAs contain a sequence, trans-activation-response (TAR) element, which is required for tat protein-mediated trans-activation of viral gene expression. We have identified a nuclear protein from extracts of HeLa cells that binds to the TAR element RNA in a sequence-specific manner. The binding of this 68-kDa polypeptide was detected by UV cross-linking proteins to TAR element RNA transcribed in vitro. Competition experiments were performed by using a partially purified preparation of the protein to quantify the relative binding affinities of TAR element RNA mutants. The binding affinity of the TAR mutants paralleled the reported ability of those mutants to support tat trans-activation in vivo. We propose that this cellular protein moderates TAR activity in vivo. Images PMID:2333305

A retinoic acid response element that overlaps an estrogen response element mediates multihormonal sensitivity in transcriptional activation of the lactoferrin gene.

PubMed

Lee, M O; Liu, Y; Zhang, X K

1995-08-01

The lactoferrin gene is highly expressed in many different tissues, and its expression is controlled by different regulators. In this report, we have defined a retinoic acid response element (RARE) in the 5'-flanking region of the lactoferrin gene promoter. The lactoferrin-RARE is composed of two AGGTCA-like motifs arranged as a direct repeat with 1-bp spacing (DR-1). A gel retardation assay demonstrated that it bound strongly with retinoid X receptor (RXR) homodimers and RXR-retinoic acid receptor (RAR) heterodimers as well as chicken ovalbumin upstream promoter transcription factor (COUP-TF) orphan receptor. In CV-1 cells, the lactoferrin-RARE linked with a heterologous thymidine kinase promoter was strongly activated by RXR homodimers in response to 9-cis-retinoic acid (9-cis-RA) but not to all-trans-RA. When the COUP-TF orphan receptor was cotransfected, the 9-cis-RA-induced RXR homodimer activity was strongly repressed. A unique feature of the lactoferrin-RARE is that it has an AGGTCA-like motif in common with an estrogen-responsive element (ERE). The composite RARE/ERE contributes to the functional interaction between retinoid receptors and the estrogen receptor (ER) and their ligands. In CV-1 cells, cotransfection of the retinoid and estrogen receptors led to mutual inhibition of the other's activity, while an RA-dependent inhibition of ER activity was observed in breast cancer cells. Furthermore, the lactoferrin-RARE/ERE showed differential transactivation activity in different cell types. RAs could activate the lactoferrin-RARE/ERE in human leukemia HL-60 cells and U937 cells but not in human breast cancer cells. By gel retardation analyses, we demonstrated that strong binding of the endogenous COUP-TF in breast cancer cells to the composite element contributed to diminished RA response in these cells. Thus, the lactoferrin-RARE/ERE functions as a signaling switch module that mediates multihormonal responsiveness in the regulation of lactoferrin gene expression.

Brake Fluid Compatibility with Hardware

DTIC Science & Technology

2014-05-19

association or emblem usage considerations. All other legal considerations are the responsibility of the author and his/her/their employer(s...10 Figure 8. Backscatter SEM Image showing Elemental Analysis Scan Locations ....................... 11 Figure 9. Surface Scan jfs9176...Elemental Analysis .................................................................... 12 Figure 10. Particle Scan jfs9177 Elemental Analysis

A spectral model for signal elements isolated from zebrafish photopic electroretinogram

PubMed Central

Nelson, Ralph; Singla, Nirmish

2009-01-01

The zebrafish photopic ERG sums isolatable elements. In each element red, blue, green and UV (r, g, b, u) cone signals combine in a way that reflects retinal organization. ERG responses to monochromatic stimuli of different wavelengths and irradiances were recorded on a white, rod suppressing background using superfused eyecups. Onset elements were isolated with glutamatergic blockers and response subtractions. CNQX blocked ionotropic (AMPA/kainate) glutamate receptors; L-AP4 or CPPG blocked metabotropic (mGluR6) glutamate receptors; TBOA blocked glutamate transporters; and L-Aspartate inactivated all glutamatergic mechanisms. Seven elements emerged: photopic PIII, the L-Aspartate-isolated cone response; b1, a CNQX-sensitive early b-wave element of inner retinal origin; PII, a photopic, CNQX-insensitive, composite b-wave element from ON bipolar cells; PIIm, an L-AP4/CPPG-sensitive, CNQX-insensitive metabotropic sub-element of PII; PIInm, an L-AP4/CPPG/CNQX-insensitive, non-metabotropic sub-element of PII; a1nm, a TBOA-sensitive, CNQX/L-AP4/CPPG-insensitive, non-metabotropic, post-photoreceptor a-wave element; and a2, a CNQX-sensitive a-wave element linked to OFF bipolar cells. The first five elements were fit with a spectral model that demonstrates independence of cone color pathways. From this Vmax and half-saturation values (k) for the contributing r- g- b- and u-cone signals were calculated. Two signal patterns emerged. For PIII or PIInm the Vmax order was Vr > Vg ≫ Vb ≈ Vu. For b1, PII, and PIIm the Vmax order was Vr ≈ Vb > Vg > Vu. In either pattern u-cone amplitude (Vu) was smallest, but u-cone sensitivity (ku362) was greatest, some 10-30 times greater than r-cone (kr570). The spectra of b1/PII/PIIm elements peaked near b-cone and u-cone absorbance maxima regardless of criteria, but the spectra of PIII/PIInm elements shifted from b- towards r-cone absorbance maxima as criterion levels increased. The greatest gains in Vmax relative to PIII occurred for the b- and u-cone signals in the b1/PII/PIIm b-wave elements. This suggests a high-gain, prolific metabotropic circuitry for b- and u-cone bipolar cells. PMID:19723365

ABF2, an ABRE-binding bZIP factor, is an essential component of glucose signaling and its overexpression affects multiple stress tolerance.

PubMed

Kim, Sunmi; Kang, Jung-Youn; Cho, Dong-Im; Park, Ji Hye; Kim, Soo Young

2004-10-01

Phytohormone abscisic acid (ABA) regulates stress-responsive gene expression during vegetative growth, which is mediated largely by cis-elements sharing the ACGTGGC consensus. Although many transcription factors are known to bind the elements in vitro, only a few have been demonstrated to have in vivo functions and their specific roles in ABA/stress responses are mostly unknown. Here, we report that ABF2, an ABF subfamily member of bZIP proteins interacting with the ABA-responsive elements, is involved in ABA/stress responses. Its overexpression altered ABA sensitivity, dehydration tolerance, and the expression levels of ABA/stress-regulated genes. Furthermore, ABF2 overexpression promoted glucose-induced inhibition of seedling development, whereas its mutation impaired glucose response. The reduced sugar sensitivity was not observed with mutants of two other ABF family members, ABF3 and ABF4. Instead, these mutants displayed defects in ABA, salt, and dehydration responses, which were not observed with the abf2 mutant. Our data indicate distinct roles of ABF family members: whereas ABF3 and ABF4 play essential roles in ABA/stress responses, ABF2 is required for normal glucose response. We also show that ABF2 overexpression affects multiple stress tolerance.

Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

NASA Astrophysics Data System (ADS)

Ejiri, Hiroyasu

2014-09-01

Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.

Immunoglobulin gene usage in the human anti-pathogen response.

PubMed

Newkirk, M M; Rioux, J D

1995-09-01

The human antibody response to foreign pathogens is generated to a relatively small number of target surface proteins and carbohydrates that nonetheless have an extensive array of epitopes. The study of human monoclonal antibodies to different pathogens shows that there are a diversity of mechanisms used to generate a sufficient repertoire of antibodies to combat the invading pathogens. Although many different immunoglobulin gene elements are used to construct the anti-pathogen response, some elements are used more often than would be expected if all elements were used randomly. For example, the immune response to Haemophilus influenzae polysaccharide appears to be quite narrow, being restricted primarily to a specific heavy-chain gene, 3-15, and a lambda light-chain family II member, 4A. In contrast, for the immune response to cytomegalovirus proteins, a wider group of gene elements is needed. It is also surprising that despite an investigator bias for IgG- rather than IgM-secreting immortal B cells (because of their high affinity and neutralizing abilities), 26% of light chains and 13% of heavy chains showed a very low level of somatic mutation, equivalent to an IgM molecule that has not undergone affinity maturation. Although some highly mutated IgG molecules are present in the anti-pathogen response, most of the monoclonal antibodies specific for viruses or bacteria have a level of somatic hypermutation similar to that of the adult IgM repertoire. A number of studies have shown that there are similarities in the antibody responses to pathogens and to self (autoantibodies).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficient Computation Of Behavior Of Aircraft Tires

NASA Technical Reports Server (NTRS)

Tanner, John A.; Noor, Ahmed K.; Andersen, Carl M.

1989-01-01

NASA technical paper discusses challenging application of computational structural mechanics to numerical simulation of responses of aircraft tires during taxing, takeoff, and landing. Presents details of three main elements of computational strategy: use of special three-field, mixed-finite-element models; use of operator splitting; and application of technique reducing substantially number of degrees of freedom. Proposed computational strategy applied to two quasi-symmetric problems: linear analysis of anisotropic tires through use of two-dimensional-shell finite elements and nonlinear analysis of orthotropic tires subjected to unsymmetric loading. Three basic types of symmetry and combinations exhibited by response of tire identified.

Expeditionary Force 21. Forward and Ready: Now and in the Future

DTIC Science & Technology

2014-03-04

single commander. Each MAGTF is composed of a command element (CE), a ground combat element ( GCE ), an aviation combat element (ACE), and logistics...headquarters group, a ground combat element ( GCE ) with one Marine Division, an aviation combat element (ACE) with one Marine Aircraft Wing, and a...remain the Marine Corps’ standard unit of deployment; however, company landing teams may take on a larger role in crisis response and may form the GCE

Regulation of acrosomal exocytosis. II. The zona pellucida-induced acrosome reaction of bovine spermatozoa is controlled by extrinsic positive regulatory elements.

PubMed

Florman, H M; First, N L

1988-08-01

The effects of accessory sex gland secretions on the zona pellucida-induced acrosome reaction of bovine spermatozoa were investigated. Soluble extracts of zonae pellucidae initiated exocytosis in ejaculated spermatozoa. This process had an ED50 of 20 ng/microliter zona pellucida protein and saturated at 50 ng/microliter (Florman and First, 1988. Dev. Biol. 128, 453-463). In epididymal sperm this dose-response relationship was shifted toward greater agonist concentrations by at least a factor of 10(3). Reconstitution of high potency agonist response was achieved in vitro by incubation of epididymal sperm with bovine seminal plasma. Reconstitution was dependent on the seminal plasma protein concentration. The ED50 of this process was 62 micrograms protein/10(8) sperm and saturation was observed with 124 micrograms protein/10(8) sperm. Agonist responses in reconstituted epididymal sperm and in ejaculated sperm were indistinguishable with regard to dependence on the zona pellucida protein concentration and the kinetics of induced acrosome reactions. Kinetic studies suggest that reconstitution is due to adsorption of regulatory factors from seminal plasma. In addition to the positive regulatory elements responsible for reconstituting activity, seminal plasma also contains negative regulatory elements which inhibit agonist response. These negative factors are inactivated during sperm capacitation, permitting the expression of positive regulators. Acting together, these regulatory elements could coordinate high affinity agonist response with the availability of eggs in vivo.

The effect of loading time on flexible pavement dynamic response: a finite element analysis

NASA Astrophysics Data System (ADS)

Yin, Hao; Solaimanian, Mansour; Kumar, Tanmay; Stoffels, Shelley

2007-12-01

Dynamic response of asphalt concrete (AC) pavements under moving load is a key component for accurate prediction of flexible pavement performance. The time and temperature dependency of AC materials calls for utilizing advanced material characterization and mechanistic theories, such as viscoelasticity and stress/strain analysis. In layered elastic analysis, as implemented in the new Mechanistic-Empirical Pavement Design Guide (MEPDG), the time dependency is accounted for by calculating the loading times at different AC layer depths. In this study, the time effect on pavement response was evaluated by means of the concept of “pseudo temperature.” With the pavement temperature measured from instrumented thermocouples, the time and temperature dependency of AC materials was integrated into one single factor, termed “effective temperature.” Via this effective temperature, pavement responses under a transient load were predicted through finite element analysis. In the finite element model, viscoelastic behavior of AC materials was characterized through relaxation moduli, while the layers with unbound granular material were assumed to be in an elastic mode. The analysis was conducted for two different AC mixtures in a simplified flexible pavement structure at two different seasons. Finite element analysis results reveal that the loading time has a more pronounced impact on pavement response in the summer for both asphalt types. The results indicate that for reasonable prediction of dynamic response in flexible pavements, the effect of the depth-dependent loading time on pavement temperature should be considered.

Two-Element Transducer for Ultrasound

NASA Technical Reports Server (NTRS)

Lecroissette, D. H.; Heyser, R. C.

1986-01-01

Separation of transmitting and receiving units improves probing of deep tissue. Ultrasonic transducer has dual elements to increase depth at which sonic images are made of biological tissue. Transducer uses separate transmitting and receiving elements, and frequency response of receiving element independently designed to accommodate attenuation of higher frequencies by tissue. New transducer intended for pulse-echo ultrasonic systems in which reflected sound pulses reveal features in tissue.

A Shear Deformable Shell Element for Laminated Composites

NASA Technical Reports Server (NTRS)

Chao, W. C.; Reddy, J. N.

1984-01-01

A three-dimensional element based on the total Lagrangian description of the motion of a layered anisotropic composite medium is developed, validated, and used to analyze layered composite shells. The element contains the following features: geometric nonlinearity, dynamic (transient) behavior, and arbitrary lamination scheme and lamina properties. Numerical results of nonlinear bending, natural vibration, and transient response are presented to illustrate the capabilities of the element.

Monte-Carlo gamma response simulation of fast/thermal neutron interactions with soil elements

USDA-ARS?s Scientific Manuscript database

Soil elemental analysis using characteristic gamma rays induced by neutrons is an effective method of in situ soil content determination. The nuclei of soil elements irradiated by neutrons issue characteristic gamma rays due to both inelastic neutron scattering (e.g., Si, C) and thermal neutron capt...

Filament condition-specific response elements control the expression of NRG1 and UME6, key transcriptional regulators of morphology and virulence in Candida albicans.

PubMed

Childers, Delma S; Kadosh, David

2015-01-01

Candida albicans is the most frequently isolated human fungal pathogen and can cause a range of mucosal and systemic infections in immunocompromised individuals. Morphogenesis, the ability to undergo a reversible transition from budding yeast to elongated filaments, is an essential virulence trait. The yeast-to-filament transition is associated with expression of genes specifically important for filamentation as well as other virulence-related processes, and is controlled, in part, by the key transcriptional regulators Nrg1 and Ume6. Both of these regulators are themselves controlled at the transcriptional level by filament-inducing environmental cues, although little is known about how this process occurs. In order to address this question and determine whether environmental signals regulate transcription of UME6 and NRG1 via distinct and/or common promoter elements, we performed promoter deletion analyses. Strains bearing promoter deletion constructs were induced to form filaments in YEPD plus 10% serum at 37°C, Spider medium (nitrogen and carbon starvation) and/or Lee's medium pH 6.8 (neutral pH) and reporter gene expression was measured. In the NRG1 promoter we identified several distinct condition-specific response elements for YEPD plus 10% serum at 37°C and Spider medium. In the UME6 promoter we also identified response elements for YEPD plus 10% serum at 37°C. While a few of these elements are distinct, others overlap with those which respond to Lee's pH 6.8 medium. Consistent with UME6 possessing a very long 5' UTR, many response elements in the UME6 promoter are located significantly upstream from the coding sequence. Our data indicate that certain distinct condition-specific elements can control expression of C. albicans UME6 and NRG1 in response to key filament-inducing environmental cues. Because C. albicans encounters a variety of host microenvironments during infection, our results suggest that UME6 and NRG1 expression can be differentially modulated by multiple signaling pathways to control filamentation and virulence in vivo.

Multivariate Analysis of the Cotton Seed Ionome Reveals a Shared Genetic Architecture

PubMed Central

Pauli, Duke; Ziegler, Greg; Ren, Min; Jenks, Matthew A.; Hunsaker, Douglas J.; Zhang, Min; Baxter, Ivan; Gore, Michael A.

2018-01-01

To mitigate the effects of heat and drought stress, a better understanding of the genetic control of physiological responses to these environmental conditions is needed. To this end, we evaluated an upland cotton (Gossypium hirsutum L.) mapping population under water-limited and well-watered conditions in a hot, arid environment. The elemental concentrations (ionome) of seed samples from the population were profiled in addition to those of soil samples taken from throughout the field site to better model environmental variation. The elements profiled in seeds exhibited moderate to high heritabilities, as well as strong phenotypic and genotypic correlations between elements that were not altered by the imposed irrigation regimes. Quantitative trait loci (QTL) mapping results from a Bayesian classification method identified multiple genomic regions where QTL for individual elements colocalized, suggesting that genetic control of the ionome is highly interrelated. To more fully explore this genetic architecture, multivariate QTL mapping was implemented among groups of biochemically related elements. This analysis revealed both additional and pleiotropic QTL responsible for coordinated control of phenotypic variation for elemental accumulation. Machine learning algorithms that utilized only ionomic data predicted the irrigation regime under which genotypes were evaluated with very high accuracy. Taken together, these results demonstrate the extent to which the seed ionome is genetically interrelated and predictive of plant physiological responses to adverse environmental conditions. PMID:29437829

Does aphid salivation affect phloem sieve element occlusion in vivo?

PubMed

Medina-Ortega, Karla J; Walker, G P

2013-12-01

To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation.

Does aphid salivation affect phloem sieve element occlusion in vivo?

PubMed Central

Medina-Ortega, Karla J.

2013-01-01

To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation. PMID:24127515

Static and free-vibrational response of semi-circular graphite-epoxy frames with thin-walled open sections

NASA Technical Reports Server (NTRS)

Collins, J. Scott; Johnson, Eric R.

1989-01-01

Experiments were conducted to measure the three-dimensional static and free vibrational response of two graphite-epoxy, thin-walled, open section frames. The frames are semi-circular with a radius of three feet, and one specimen has an I cross section and the other has a channel cross section. The flexibility influence coefficients were measured in static tests for loads applied at midspan with the ends of the specimens clamped. Natural frequencies and modes were determined from vibrational tests for free and clamped end conditions. The experimental data is used to evaluate a new finite element which was developed specifically for the analysis of curved, thin-walled structures. The formulation of the element is based on a Vlasov-type, thin-walled, curved beam theory. The predictions from the finite element program generally correlated well with the experimental data for the symmetric I-specimen. Discrepancies in some of the data were found to be due to flexibility in the clamped end conditions. With respect to the data for the channel specimen, the correlation was less satisfactory. The finite element analysis predicted the out-of-plane response of the channel specimen reasonably well, but large discrepancies occurred between the predicted in-plane response and the experimental data. The analysis predicted a much more compliant in-plane response than was observed in the experiments.

Direct Response Marketing. Educational Approaches for an Emerging Discipline.

ERIC Educational Resources Information Center

Grossman, Robert J.

1982-01-01

Examines factors leading to the growth in direct response marketing; elements that differentiate direct response marketing from marketing as a whole; and workshops designed for educators to develop curriculum in direct response marketing. (CT)

Androgen receptor stimulates bone sialoprotein (BSP) gene transcription via cAMP response element and activator protein 1/glucocorticoid response elements.

PubMed

Takai, Hideki; Nakayama, Youhei; Kim, Dong-Soon; Arai, Masato; Araki, Shouta; Mezawa, Masaru; Nakajima, Yu; Kato, Naoko; Masunaga, Hiroshi; Ogata, Yorimasa

2007-09-01

Bone sialoprotein (BSP) is an early marker of osteoblast differentiation. Androgens are steroid hormones that are essential for skeletal development. The androgen receptor (AR) is a transcription factor and a member of the steroid receptor superfamily that plays an important role in male sexual differentiation and prostate cell proliferation. To determine the molecular mechanism involved in the stimulation of bone formation, we have analyzed the effects of androgens and AR effects on BSP gene transcription. AR protein levels were increased after AR overexpression in ROS17/2.8 cells. BSP mRNA levels were increased by AR overexpression. However, the endogenous and overexpressed BSP mRNA levels were not changed by DHT (10(-8) M, 24 h). Whereas luciferase (LUC) activities in all constructs, including a short construct (nts -116 to +60), were increased by AR overexpression, the basal and LUC activities enhanced by AR overexpression were not induced by DHT (10(-8)M, 24 h). The effect of AR overexpression was abrogated by 2 bp mutations in either the cAMP response element (CRE) or activator protein 1 (AP1)/glucocorticoid response element (GRE). Gel shift analyses showed that AR overexpression increased binding to the CRE and AP1/GRE elements. Notably, the CRE-protein complexes were supershifted by phospho-CREB antibody, and CREB, c-Fos, c-Jun, and AR antibodies disrupted the complexes formation. The AP1/GRE-protein complexes were supershifted by c-Fos antibody and c-Jun, and AR antibodies disrupted the complexes formation. These studies demonstrate that AR stimulates BSP gene transcription by targeting the CRE and AP1/GRE elements in the promoter of the rat BSP gene.

Dehydration responsive element binding transcription factors and their applications for the engineering of stress tolerance.

PubMed

Agarwal, Pradeep K; Gupta, Kapil; Lopato, Sergiy; Agarwal, Parinita

2017-04-01

Dehydration responsive element binding (DREB) factors or CRT element binding factors (CBFs) are members of the AP2/ERF family, which comprises a large number of stress-responsive regulatory genes. This review traverses almost two decades of research, from the discovery of DREB/CBF factors to their optimization for application in plant biotechnology. In this review, we describe (i) the discovery, classification, structure, and evolution of DREB genes and proteins; (ii) induction of DREB genes by abiotic stresses and involvement of their products in stress responses; (iii) protein structure and DNA binding selectivity of different groups of DREB proteins; (iv) post-transcriptional and post-translational mechanisms of DREB transcription factor (TF) regulation; and (v) physical and/or functional interaction of DREB TFs with other proteins during plant stress responses. We also discuss existing issues in applications of DREB TFs for engineering of enhanced stress tolerance and improved performance under stress of transgenic crop plants. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A versatile transfection assay system to evaluate the biological effects of diverse industrial chemicals.

PubMed

Koizumi, Shinji; Ohno, Shotaro; Otsuka, Fuminori

2012-01-01

Gene expression processes are now recognized as important targets of the toxic effects exerted by industrial chemicals. The transient transfection assay is a powerful tool to evaluate such effects. Thus, we developed a versatile assay system by constructing a basic reporter plasmid in which the regulatory DNA sequence to be studied can easily be substituted. To verify the performance of this system, reporter plasmids carrying any of the three distinct regulatory sequences, estrogen responsive element (ERE), glucocorticoid responsive element (GRE) and xenobiotic responsive element (XRE) were constructed. After transfection of human cells, these plasmids successfully expressed the relevant reporter genes in response to specific inducers, β-estradiol, dexamethasone and 3-methylcholanthrene, respectively. Several industrial chemicals were assayed using these reporter plasmids, and the ability of p-dimethylaminoazobenzene to elevate GRE- and XRE-mediated transcription was detected. α-Naphthylamine and o-tolidine were also observed to increase the XRE-mediated response. The transfection assay system established here will be useful to evaluate the effects of a wide variety of industrial chemicals.

Transcriptional responses of Arabidopsis thaliana to chewing and sucking insect herbivores

DOE PAGES

Appel, Heidi M.; Fescemyer, Howard; Ehlting, Juergen; ...

2014-11-14

We tested the hypothesis that Arabidopsis can recognize and respond differentially to insect species at the transcriptional level using a genome wide microarray. Transcriptional reprogramming was characterized using co-expression analysis in damaged and undamaged leaves at two times in response to mechanical wounding and four insect species. In all, 2778 (10.6%) of annotated genes on the array were differentially expressed in at least one treatment. Responses differed mainly between aphid and caterpillar and sampling times. Responses to aphids and caterpillars shared only 10% of up-regulated and 8% of down-regulated genes. Responses to two caterpillars shared 21 and 12% of up-more » and down-regulated genes, whereas responses to the two aphids shared only 7 and 4% of up-regulated and down-regulated genes. Overlap in genes expressed between 6 and 24 h was 3–15%, and depended on the insect species. Responses in attacked and unattacked leaves differed at 6 h but converged by 24 h. Genes responding to the insects are also responsive to many stressors and included primary metabolism. Aphids down-regulated amino acid catabolism; caterpillars stimulated production of amino acids involved in glucosinolate synthesis. Co-expression analysis revealed 17 response networks. Transcription factors were a major portion of differentially expressed genes throughout and responsive genes shared most of the known or postulated binding sites. However, cis-element composition of genes down regulated by the aphid M. persicae was unique, as were those of genes down-regulated by caterpillars. As many as 20 cis-elements were over-represented in one or more treatments, including some from well-characterized classes and others as yet uncharacterized. We suggest that transcriptional changes elicited by wounding and insects are heavily influenced by transcription factors and involve both enrichment of a common set of cis-elements and a unique enrichment of a few cis-elements in responding genes.« less

Transcriptional responses of Arabidopsis thaliana to chewing and sucking insect herbivores

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

Appel, Heidi M.; Fescemyer, Howard; Ehlting, Juergen

We tested the hypothesis that Arabidopsis can recognize and respond differentially to insect species at the transcriptional level using a genome wide microarray. Transcriptional reprogramming was characterized using co-expression analysis in damaged and undamaged leaves at two times in response to mechanical wounding and four insect species. In all, 2778 (10.6%) of annotated genes on the array were differentially expressed in at least one treatment. Responses differed mainly between aphid and caterpillar and sampling times. Responses to aphids and caterpillars shared only 10% of up-regulated and 8% of down-regulated genes. Responses to two caterpillars shared 21 and 12% of up-more » and down-regulated genes, whereas responses to the two aphids shared only 7 and 4% of up-regulated and down-regulated genes. Overlap in genes expressed between 6 and 24 h was 3–15%, and depended on the insect species. Responses in attacked and unattacked leaves differed at 6 h but converged by 24 h. Genes responding to the insects are also responsive to many stressors and included primary metabolism. Aphids down-regulated amino acid catabolism; caterpillars stimulated production of amino acids involved in glucosinolate synthesis. Co-expression analysis revealed 17 response networks. Transcription factors were a major portion of differentially expressed genes throughout and responsive genes shared most of the known or postulated binding sites. However, cis-element composition of genes down regulated by the aphid M. persicae was unique, as were those of genes down-regulated by caterpillars. As many as 20 cis-elements were over-represented in one or more treatments, including some from well-characterized classes and others as yet uncharacterized. We suggest that transcriptional changes elicited by wounding and insects are heavily influenced by transcription factors and involve both enrichment of a common set of cis-elements and a unique enrichment of a few cis-elements in responding genes.« less

Genome-wide analysis of ABA-responsive elements ABRE and CE3 reveals divergent patterns in Arabidopsis and rice

PubMed Central

Gómez-Porras, Judith L; Riaño-Pachón, Diego Mauricio; Dreyer, Ingo; Mayer, Jorge E; Mueller-Roeber, Bernd

2007-01-01

Background In plants, complex regulatory mechanisms are at the core of physiological and developmental processes. The phytohormone abscisic acid (ABA) is involved in the regulation of various such processes, including stomatal closure, seed and bud dormancy, and physiological responses to cold, drought and salinity stress. The underlying tissue or plant-wide control circuits often include combinatorial gene regulatory mechanisms and networks that we are only beginning to unravel with the help of new molecular tools. The increasing availability of genomic sequences and gene expression data enables us to dissect ABA regulatory mechanisms at the individual gene expression level. In this paper we used an in-silico-based approach directed towards genome-wide prediction and identification of specific features of ABA-responsive elements. In particular we analysed the genome-wide occurrence and positional arrangements of two well-described ABA-responsive cis-regulatory elements (CREs), ABRE and CE3, in thale cress (Arabidopsis thaliana) and rice (Oryza sativa). Results Our results show that Arabidopsis and rice use the ABA-responsive elements ABRE and CE3 distinctively. Earlier reports for various monocots have identified CE3 as a coupling element (CE) associated with ABRE. Surprisingly, we found that while ABRE is equally abundant in both species, CE3 is practically absent in Arabidopsis. ABRE-ABRE pairs are common in both genomes, suggesting that these can form functional ABA-responsive complexes (ABRCs) in Arabidopsis and rice. Furthermore, we detected distinct combinations, orientation patterns and DNA strand preferences of ABRE and CE3 motifs in rice gene promoters. Conclusion Our computational analyses revealed distinct recruitment patterns of ABA-responsive CREs in upstream sequences of Arabidopsis and rice. The apparent absence of CE3s in Arabidopsis suggests that another CE pairs with ABRE to establish a functional ABRC capable of interacting with transcription factors. Further studies will be needed to test whether the observed differences are extrapolatable to monocots and dicots in general, and to understand how they contribute to the fine-tuning of the hormonal response. The outcome of our investigation can now be used to direct future experimentation designed to further dissect the ABA-dependent regulatory networks. PMID:17672917

Genome-wide analysis of ABA-responsive elements ABRE and CE3 reveals divergent patterns in Arabidopsis and rice.

PubMed

Gómez-Porras, Judith L; Riaño-Pachón, Diego Mauricio; Dreyer, Ingo; Mayer, Jorge E; Mueller-Roeber, Bernd

2007-08-01

In plants, complex regulatory mechanisms are at the core of physiological and developmental processes. The phytohormone abscisic acid (ABA) is involved in the regulation of various such processes, including stomatal closure, seed and bud dormancy, and physiological responses to cold, drought and salinity stress. The underlying tissue or plant-wide control circuits often include combinatorial gene regulatory mechanisms and networks that we are only beginning to unravel with the help of new molecular tools. The increasing availability of genomic sequences and gene expression data enables us to dissect ABA regulatory mechanisms at the individual gene expression level. In this paper we used an in-silico-based approach directed towards genome-wide prediction and identification of specific features of ABA-responsive elements. In particular we analysed the genome-wide occurrence and positional arrangements of two well-described ABA-responsive cis-regulatory elements (CREs), ABRE and CE3, in thale cress (Arabidopsis thaliana) and rice (Oryza sativa). Our results show that Arabidopsis and rice use the ABA-responsive elements ABRE and CE3 distinctively. Earlier reports for various monocots have identified CE3 as a coupling element (CE) associated with ABRE. Surprisingly, we found that while ABRE is equally abundant in both species, CE3 is practically absent in Arabidopsis. ABRE-ABRE pairs are common in both genomes, suggesting that these can form functional ABA-responsive complexes (ABRCs) in Arabidopsis and rice. Furthermore, we detected distinct combinations, orientation patterns and DNA strand preferences of ABRE and CE3 motifs in rice gene promoters. Our computational analyses revealed distinct recruitment patterns of ABA-responsive CREs in upstream sequences of Arabidopsis and rice. The apparent absence of CE3s in Arabidopsis suggests that another CE pairs with ABRE to establish a functional ABRC capable of interacting with transcription factors. Further studies will be needed to test whether the observed differences are extrapolatable to monocots and dicots in general, and to understand how they contribute to the fine-tuning of the hormonal response. The outcome of our investigation can now be used to direct future experimentation designed to further dissect the ABA-dependent regulatory networks.

Finite-element nonlinear transient response computer programs PLATE 1 and CIVM-PLATE 1 for the analysis of panels subjected to impulse or impact loads

NASA Technical Reports Server (NTRS)

Spilker, R. L.; Witmer, E. A.; French, S. E.; Rodal, J. J. A.

1980-01-01

Two computer programs are described for predicting the transient large deflection elastic viscoplastic responses of thin single layer, initially flat unstiffened or integrally stiffened, Kirchhoff-Lov ductile metal panels. The PLATE 1 program pertains to structural responses produced by prescribed externally applied transient loading or prescribed initial velocity distributions. The collision imparted velocity method PLATE 1 program concerns structural responses produced by impact of an idealized nondeformable fragment. Finite elements are used to represent the structure in both programs. Strain hardening and strain rate effects of initially isotropic material are considered.

The Serum Response Factor and a Putative Novel Transcription Factor Regulate Expression of the Immediate-Early Gene Arc/Arg3.1 in Cultured Cortical Neurons

PubMed Central

Pintchovski, Sean A.; Peebles, Carol L.; Kim, Hong Joo; Verdin, Eric; Finkbeiner, Steven

2010-01-01

The immediate-early effector gene Arc/Arg3.1 is robustly upregulated by synaptic activity associated with learning and memory. Here we show in primary cortical neuron culture that diverse stimuli induce Arc expression through new transcription. Searching for regulatory regions important for Arc transcription, we found nine DNaseI-sensitive nucleosome-depleted sites at this genomic locus. A reporter gene encompassing these sites responded to synaptic activity in an NMDA receptor–dependent manner, consistent with endogenous Arc mRNA. Responsiveness mapped to two enhancer regions ∼6.5 kb and ∼1.4 kb upstream of Arc. We dissected these regions further and found that the proximal enhancer contains a functional and conserved “Zeste-like” response element that binds a putative novel nuclear protein in neurons. Therefore, activity regulates Arc transcription partly by a novel signaling pathway. We also found that the distal enhancer has a functional and highly conserved serum response element. This element binds serum response factor, which is recruited by synaptic activity to regulate Arc. Thus, Arc is the first target of serum response factor that functions at synapses to mediate plasticity. PMID:19193899

Functional dissection of drought-responsive gene expression patterns in Cynodon dactylon L.

PubMed

Kim, Changsoo; Lemke, Cornelia; Paterson, Andrew H

2009-05-01

Water deficit is one of the main abiotic factors that affect plant productivity in subtropical regions. To identify genes induced during the water stress response in Bermudagrass (Cynodon dactylon), cDNA macroarrays were used. The macroarray analysis identified 189 drought-responsive candidate genes from C. dactylon, of which 120 were up-regulated and 69 were down-regulated. The candidate genes were classified into seven groups by cluster analysis of expression levels across two intensities and three durations of imposed stress. Annotation using BLASTX suggested that up-regulated genes may be involved in proline biosynthesis, signal transduction pathways, protein repair systems, and removal of toxins, while down-regulated genes were mostly related to basic plant metabolism such as photosynthesis and glycolysis. The functional classification of gene ontology (GO) was consistent with the BLASTX results, also suggesting some crosstalk between abiotic and biotic stress. Comparative analysis of cis-regulatory elements from the candidate genes implicated specific elements in drought response in Bermudagrass. Although only a subset of genes was studied, Bermudagrass shared many drought-responsive genes and cis-regulatory elements with other botanical models, supporting a strategy of cross-taxon application of drought-responsive genes, regulatory cues, and physiological-genetic information.

The SOS response is permitted in Escherichia coli strains deficient in the expression of the mazEF pathway.

PubMed

Kalderon, Ziva; Kumar, Sathish; Engelberg-Kulka, Hanna

2014-01-01

The Escherichia coli (E. coli) SOS response is the largest, most complex, and best characterized bacterial network induced by DNA damage. It is controlled by a complex network involving the RecA and LexA proteins. We have previously shown that the SOS response to DNA damage is inhibited by various elements involved in the expression of the E. coli toxin-antitoxin mazEF pathway. Since the mazEF module is present on the chromosomes of most E. coli strains, here we asked: Why is the SOS response found in so many E. coli strains? Is the mazEF module present but inactive in those strains? We examined three E. coli strains used for studies of the SOS response, strains AB1932, BW25113, and MG1655. We found that each of these strains is either missing or inhibiting one of several elements involved in the expression of the mazEF-mediated death pathway. Thus, the SOS response only takes place in E. coli cells in which one or more elements of the E. coli toxin-antitoxin module mazEF or its downstream pathway is not functioning.

The SOS Response is Permitted in Escherichia coli Strains Deficient in the Expression of the mazEF Pathway

PubMed Central

Kalderon, Ziva; Kumar, Sathish; Engelberg-Kulka, Hanna

2014-01-01

The Escherichia coli (E. coli) SOS response is the largest, most complex, and best characterized bacterial network induced by DNA damage. It is controlled by a complex network involving the RecA and LexA proteins. We have previously shown that the SOS response to DNA damage is inhibited by various elements involved in the expression of the E. coli toxin-antitoxin mazEF pathway. Since the mazEF module is present on the chromosomes of most E. coli strains, here we asked: Why is the SOS response found in so many E. coli strains? Is the mazEF module present but inactive in those strains? We examined three E. coli strains used for studies of the SOS response, strains AB1932, BW25113, and MG1655. We found that each of these strains is either missing or inhibiting one of several elements involved in the expression of the mazEF-mediated death pathway. Thus, the SOS response only takes place in E. coli cells in which one or more elements of the E. coli toxin-antitoxin module mazEF or its downstream pathway is not functioning. PMID:25470502

Involvement of Ethylene in Stress-Induced Expression of the TLC1.1 Retrotransposon from Lycopersicon chilense Dun.1[w

PubMed Central

Tapia, Gerardo; Verdugo, Isabel; Yañez, Mónica; Ahumada, Iván; Theoduloz, Cristina; Cordero, Cecilia; Poblete, Fernando; González, Enrique; Ruiz-Lara, Simón

2005-01-01

The TLC1 family is one of the four families of long terminal repeat (LTR) retrotransposons identified in the genome of Lycopersicon chilense. Here, we show that this family of retroelements is transcriptionally active and its expression is induced in response to diverse stress conditions such as wounding, protoplast preparation, and high salt concentrations. Several stress-associated signaling molecules, including ethylene, methyl jasmonate, salicylic acid, and 2,4-dichlorophenoxyacetic acid, are capable of inducing TLC1 family expression in vivo. A representative of this family, named TLC1.1, was isolated from a genomic library from L. chilense. Transient expression assays in leaf protoplasts and stably transformed tobacco (Nicotiana tabacum) plants demonstrate that the U3 domain of the 5′-LTR region of this element can drive stress-induced transcriptional activation of the β-glucuronidase reporter gene. Two 57-bp tandem repeated sequences are found in this region, including an 8-bp motif, ATTTCAAA, previously identified as an ethylene-responsive element box in the promoter region of ethylene-induced genes. Expression analysis of wild-type LTR and single and double ethylene-responsive element box mutants fused to the β-glucuronidase gene shows that these elements are required for ethylene-responsive gene expression in protoplasts and transgenic plants. We suggest that ethylene-dependent signaling is the main signaling pathway involved in the regulation of the expression of the TLC1.1 element from L. chilense. PMID:16040666

Resveratrol stimulates c-Fos gene transcription via activation of ERK1/2 involving multiple genetic elements.

PubMed

Thiel, Gerald; Rössler, Oliver G

2018-06-05

The polyphenol resveratrol is found in many plant and fruits and is a constituent of our diet. Resveratrol has been proposed to have chemopreventive and anti-inflammatory activities. On the cellular level, resveratrol activates stimulus-regulated transcription factors. To identify resveratrol-responsive elements within a natural gene promoter, the molecular pathway leading to c-Fos gene expression by resveratrol was dissected. The c-Fos gene encodes a basic region leucine zipper transcription factor and is a prototype of an immediate-early gene that is regulated by a wide range of signaling molecules. We analyzed chromatin-integrated c-Fos promoter-luciferase reporter genes where transcription factor binding sites were destroyed by point mutations or deletion mutagenesis. The results show that mutation of the binding sites for serum response factor (SRF), activator protein-1 (AP-1) and cAMP response element binding protein (CREB) significantly reduced reporter gene transcription following stimulation of the cells with resveratrol. Inactivation of the binding sites for signal transducer and activator of transcription (STAT) or ternary complex factors did not influence resveratrol-regulated c-Fos promoter activity. Thus, the c-Fos promoter contains three resveratrol-responsive elements, the cAMP response element (CRE), and the binding sites for SRF and AP-1. Moreover, we show that the transcriptional activation potential of the c-Fos protein is increased in resveratrol-stimulated cells, indicating that the biological activity of c-Fos is elevated by resveratrol stimulation. Pharmacological and genetic experiments revealed that the protein kinase ERK1/2 is the signal transducer that connects resveratrol treatment with the c-Fos gene. Copyright © 2018 Elsevier B.V. All rights reserved.

Cryptic glucocorticoid receptor-binding sites pervade genomic NF-κB response elements.

PubMed

Hudson, William H; Vera, Ian Mitchelle S de; Nwachukwu, Jerome C; Weikum, Emily R; Herbst, Austin G; Yang, Qin; Bain, David L; Nettles, Kendall W; Kojetin, Douglas J; Ortlund, Eric A

2018-04-06

Glucocorticoids (GCs) are potent repressors of NF-κB activity, making them a preferred choice for treatment of inflammation-driven conditions. Despite the widespread use of GCs in the clinic, current models are inadequate to explain the role of the glucocorticoid receptor (GR) within this critical signaling pathway. GR binding directly to NF-κB itself-tethering in a DNA binding-independent manner-represents the standing model of how GCs inhibit NF-κB-driven transcription. We demonstrate that direct binding of GR to genomic NF-κB response elements (κBREs) mediates GR-driven repression of inflammatory gene expression. We report five crystal structures and solution NMR data of GR DBD-κBRE complexes, which reveal that GR recognizes a cryptic response element between the binding footprints of NF-κB subunits within κBREs. These cryptic sequences exhibit high sequence and functional conservation, suggesting that GR binding to κBREs is an evolutionarily conserved mechanism of controlling the inflammatory response.

A Modal Model to Simulate Typical Structural Dynamic Nonlinearity [PowerPoint

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

Mayes, Randall L.; Pacini, Benjamin Robert; Roettgen, Dan

2016-01-01

Some initial investigations have been published which simulate nonlinear response with almost traditional modal models: instead of connecting the modal mass to ground through the traditional spring and damper, a nonlinear Iwan element was added. This assumes that the mode shapes do not change with amplitude and there are no interactions between modal degrees of freedom. This work expands on these previous studies. An impact experiment is performed on a structure which exhibits typical structural dynamic nonlinear response, i.e. weak frequency dependence and strong damping dependence on the amplitude of vibration. Use of low level modal test results in combinationmore » with high level impacts are processed using various combinations of modal filtering, the Hilbert Transform and band-pass filtering to develop response data that are then fit with various nonlinear elements to create a nonlinear pseudo-modal model. Simulations of forced response are compared with high level experimental data for various nonlinear element assumptions.« less

A Modal Model to Simulate Typical Structural Dynamic Nonlinearity

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

Pacini, Benjamin Robert; Mayes, Randall L.; Roettgen, Daniel R

2015-10-01

Some initial investigations have been published which simulate nonlinear response with almost traditional modal models: instead of connecting the modal mass to ground through the traditional spring and damper, a nonlinear Iwan element was added. This assumes that the mode shapes do not change with amplitude and there are no interactions between modal degrees of freedom. This work expands on these previous studies. An impact experiment is performed on a structure which exhibits typical structural dynamic nonlinear response, i.e. weak frequency dependence and strong damping dependence on the amplitude of vibration. Use of low level modal test results in combinationmore » with high level impacts are processed using various combinations of modal filtering, the Hilbert Transform and band-pass filtering to develop response data that are then fit with various nonlinear elements to create a nonlinear pseudo-modal model. Simulations of forced response are compared with high level experimental data for various nonlinear element assumptions.« less

Endoplasmic reticulum stress-responsive transcription factor ATF6α directs recruitment of the Mediator of RNA polymerase II transcription and multiple histone acetyltransferase complexes.

PubMed

Sela, Dotan; Chen, Lu; Martin-Brown, Skylar; Washburn, Michael P; Florens, Laurence; Conaway, Joan Weliky; Conaway, Ronald C

2012-06-29

The basic leucine zipper transcription factor ATF6α functions as a master regulator of endoplasmic reticulum (ER) stress response genes. Previous studies have established that, in response to ER stress, ATF6α translocates to the nucleus and activates transcription of ER stress response genes upon binding sequence specifically to ER stress response enhancer elements in their promoters. In this study, we investigate the biochemical mechanism by which ATF6α activates transcription. By exploiting a combination of biochemical and multidimensional protein identification technology-based mass spectrometry approaches, we have obtained evidence that ATF6α functions at least in part by recruiting to the ER stress response enhancer elements of ER stress response genes a collection of RNA polymerase II coregulatory complexes, including the Mediator and multiple histone acetyltransferase complexes, among which are the Spt-Ada-Gcn5 acetyltransferase (SAGA) and Ada-Two-A-containing (ATAC) complexes. Our findings shed new light on the mechanism of action of ATF6α, and they outline a straightforward strategy for applying multidimensional protein identification technology mass spectrometry to determine which RNA polymerase II transcription factors and coregulators are recruited to promoters and other regulatory elements to control transcription.

Influence of foundation mass and surface roughness on dynamic response of beam on dynamic foundation subjected to the moving load

NASA Astrophysics Data System (ADS)

Tran Quoc, Tinh; Khong Trong, Toan; Luong Van, Hai

2018-04-01

In this paper, Improved Moving Element Method (IMEM) is used to analyze the dynamic response of Euler-Bernoulli beam structures on the dynamic foundation model subjected to the moving load. The effects of characteristic foundation model parameters such as Winkler stiffness, shear layer based on the Pasternak model, viscoelastic dashpot and characteristic parameter of mass on foundation. Beams are modeled by moving elements while the load is fixed. Based on the principle of the publicly virtual balancing and the theory of moving element method, the motion differential equation of the system is established and solved by means of the numerical integration based on the Newmark algorithm. The influence of mass on foundation and the roughness of the beam surface on the dynamic response of beam are examined in details.

Common Elements for the Psychotherapeutic Management of Patients with Self Injurious Behavior

ERIC Educational Resources Information Center

Schiavone, Francesca L.; Links, Paul S.

2013-01-01

Objectives: Current research suggests that effective psychotherapies for Self Injurious Behavior (SIB) in the context of Borderline Personality Disorder (BPD) contain generic common elements which are responsible for their success. Because of the links between BPD, SIB, and child abuse, it is likely that these common elements can also be applied…

Measurement of Trace Elements During the Development and Immune Response of Heliothis virescens Larvae

USDA-ARS?s Scientific Manuscript database

While many studies have examined the effect of microbial infections on the status of trace elements in mammalian tissues, similar studies have not been performed in insects. We used inductively coupled plasma-mass spectrometry (ICP-MS) to quantify changes in trace elements of Mg, Mn, Fe, Cu, Zn and ...

PC board mount corrosion sensitive sensor

DOEpatents

Robinson, Alex L.; Casias, Adrian L.; Pfeifer, Kent B.; Laguna, George R.

2016-03-22

The present invention relates to surface mount structures including a capacitive element or a resistive element, where the element has a property that is responsive to an environmental condition. In particular examples, the structure can be optionally coupled to a printed circuit board. Other apparatuses, surface mountable structures, and methods of use are described herein.

Finite element modelling of aluminum alloy 2024-T3 under transverse impact loading

NASA Astrophysics Data System (ADS)

Abdullah, Ahmad Sufian; Kuntjoro, Wahyu; Yamin, A. F. M.

2017-12-01

Fiber metal laminate named GLARE is a new aerospace material which has great potential to be widely used in future lightweight aircraft. It consists of aluminum alloy 2024-T3 and glass-fiber reinforced laminate. In order to produce reliable finite element model of impact response or crashworthiness of structure made of GLARE, one can initially model and validate the finite element model of the impact response of its constituents separately. The objective of this study was to develop a reliable finite element model of aluminum alloy 2024-T3 under low velocity transverse impact loading using commercial software ABAQUS. Johnson-Cook plasticity and damage models were used to predict the alloy's material properties and impact behavior. The results of the finite element analysis were compared to the experiment that has similar material and impact conditions. Results showed good correlations in terms of impact forces, deformation and failure progressions which concluded that the finite element model of 2024-T3 aluminum alloy under low velocity transverse impact condition using Johnson-Cook plastic and damage models was reliable.

High order Nyström method for elastodynamic scattering

NASA Astrophysics Data System (ADS)

Chen, Kun; Gurrala, Praveen; Song, Jiming; Roberts, Ron

2016-02-01

Elastic waves in solids find important applications in ultrasonic non-destructive evaluation. The scattering of elastic waves has been treated using many approaches like the finite element method, boundary element method and Kirchhoff approximation. In this work, we propose a novel accurate and efficient high order Nyström method to solve the boundary integral equations for elastodynamic scattering problems. This approach employs high order geometry description for the element, and high order interpolation for fields inside each element. Compared with the boundary element method, this approach makes the choice of the nodes for interpolation based on the Gaussian quadrature, which renders matrix elements for far field interaction free from integration, and also greatly simplifies the process for singularity and near singularity treatment. The proposed approach employs a novel efficient near singularity treatment that makes the solver able to handle extreme geometries like very thin penny-shaped crack. Numerical results are presented to validate the approach. By using the frequency domain response and performing the inverse Fourier transform, we also report the time domain response of flaw scattering.

Experimental analysis of synchronization and dynamics in an automobile as a complex system

NASA Astrophysics Data System (ADS)

González-Cruz, C. A.; Jáuregui-Correa, J. C.; López-Cajún, C.; Sen, M.; Domínguez-González, A.

2015-08-01

A complex system is composed of many interacting elements, and its behavior, as a whole, can be quite different from that of the individual elements. An automobile is an example of a common mechanical system composed of a large number of individual elements. These elements are connected through soft and hard linkages that transmit motion to each other. This paper proposes a variety of analytical tools to study experimental data from complex systems using two elements of an automobile as an example. Accelerometer measurements were taken from two elements within an automobile: the door and the dashboard. Two types of data were collected: response to impact loading, and response to road excitation of the automobile driven at different speeds. The signals were processed via Fourier and wavelet transforms, cross-correlation coefficients, Hilbert transform, and Kuramoto order parameters. A new parameter, called the order-deficit parameter, is introduced. Considerable, but not complete, synchronization can be found between the accelerations measured at these two locations in the automobile, and the degree of synchronization is quantified using the order-deficit parameter.

Finite Element Analysis of the Random Response Suppression of Composite Panels at Elevated Temperatures using Shape Memory Alloy Fibers

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Zhong, Z. W.; Mei, Chuh

1994-01-01

A feasibility study on the use of shape memory alloys (SMA) for suppression of the random response of composite panels due to acoustic loads at elevated temperatures is presented. The constitutive relations for a composite lamina with embedded SMA fibers are developed. The finite element governing equations and the solution procedures for a composite plate subjected to combined acoustic and thermal loads are presented. Solutions include: 1) Critical buckling temperature; 2) Flat panel random response; 3) Thermal postbuckling deflection; 4) Random response of a thermally buckled panel. The preliminary results demonstrate that the SMA fibers can completely eliminate the thermal postbuckling deflection and significantly reduce the random response at elevated temperatures.

The transcriptional regulatory network in the drought response and its crosstalk in abiotic stress responses including drought, cold, and heat.

PubMed

Nakashima, Kazuo; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

2014-01-01

Drought negatively impacts plant growth and the productivity of crops around the world. Understanding the molecular mechanisms in the drought response is important for improvement of drought tolerance using molecular techniques. In plants, abscisic acid (ABA) is accumulated under osmotic stress conditions caused by drought, and has a key role in stress responses and tolerance. Comprehensive molecular analyses have shown that ABA regulates the expression of many genes under osmotic stress conditions, and the ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. Transcription factors (TFs) are master regulators of gene expression. ABRE-binding protein and ABRE-binding factor TFs control gene expression in an ABA-dependent manner. SNF1-related protein kinases 2, group A 2C-type protein phosphatases, and ABA receptors were shown to control the ABA signaling pathway. ABA-independent signaling pathways such as dehydration-responsive element-binding protein TFs and NAC TFs are also involved in stress responses including drought, heat, and cold. Recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress responses. The important roles of these TFs in crosstalk among abiotic stress responses will be discussed. Control of ABA or stress signaling factor expression can improve tolerance to environmental stresses. Recent studies using crops have shown that stress-specific overexpression of TFs improves drought tolerance and grain yield compared with controls in the field.

The molecular basis of ethylene signalling in Arabidopsis

NASA Technical Reports Server (NTRS)

Woeste, K.; Kieber, J. J.; Evans, M. L. (Principal Investigator)

1998-01-01

The simple gas ethylene profoundly influences plants at nearly every stage of growth and development. In the past ten years, the use of a genetic approach, based on the triple response phenotype, has been a powerful tool for investigating the molecular events that underlie these effects. Several fundamental elements of the pathway have been described: a receptor with homology to bacterial two-component histidine kinases (ETR1), elements of a MAP kinase cascade (CTR1) and a putative transcription factor (EIN3). Taken together, these elements can be assembled into a simple, linear model for ethylene signalling that accounts for most of the well-characterized ethylene mediated responses.

MaRAP2-4, a waterlogging-responsive ERF from Mentha, regulates bidirectional sugar transporter AtSWEET10 to modulate stress response in Arabidopsis.

PubMed

Phukan, Ujjal J; Jeena, Gajendra Singh; Tripathi, Vineeta; Shukla, Rakesh Kumar

2018-01-01

As waterlogging and successive events severely influence growth and development of economically important plants, we attempted to characterize the role of a waterlogging-responsive group I (A-6) ethylene response factor (MaRAP2-4) from Mentha arvensis. Waterlogging, ethylene and methyl jasmonate rapidly induced the expression of MaRAP2-4. MaRAP2-4 interacted with multiple cis-elements like dehydration response elements (DRE1/2), anoxia/jasmonic acid response element (JARE) and GCC box showing its involvement in multiple responses. MaRAP2-4 localizes in the nucleus and acts as a transcriptional activator. Truncation and internal deletion identified a 20 amino acids potential transactivation domain (PLPSSVDAKLEAICQSLAIN) in MaRAP2-4. MaRAP2-4 transgenic Arabidopsis showed enhanced waterlogging and subsequent oxidative stress tolerance. Microarray analysis revealed that within up-regulated genes 483, 212 and 132 promoters carry either single or multiple copies of DRE, JARE and GCC cis-element/s, respectively. Within these promoters, a large section belongs to carbohydrate metabolism/transport, including many SWEET transporters. Further analysis showed MaRAP2-4 specifically targets two positions in AtSWEEET10 promoter carrying DRE and/or GCC box that might regulate carbohydrate availability and waterlogging tolerance. These results demonstrate that MaRAP2-4 is a positive regulator of waterlogging tolerance, and as energy-consuming processes such as carbohydrate biosynthesis are reduced under waterlogging-induced hypoxia, sugar transport through SWEETs may be the primary option to make sugar available to the required tissue. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Mechanical Stress Induces Biotic and Abiotic Stress Responses via a Novel cis-Element

PubMed Central

Walley, Justin W; Coughlan, Sean; Hudson, Matthew E; Covington, Michael F; Kaspi, Roy; Banu, Gopalan; Harmer, Stacey L; Dehesh, Katayoon

2007-01-01

Plants are continuously exposed to a myriad of abiotic and biotic stresses. However, the molecular mechanisms by which these stress signals are perceived and transduced are poorly understood. To begin to identify primary stress signal transduction components, we have focused on genes that respond rapidly (within 5 min) to stress signals. Because it has been hypothesized that detection of physical stress is a mechanism common to mounting a response against a broad range of environmental stresses, we have utilized mechanical wounding as the stress stimulus and performed whole genome microarray analysis of Arabidopsis thaliana leaf tissue. This led to the identification of a number of rapid wound responsive (RWR) genes. Comparison of RWR genes with published abiotic and biotic stress microarray datasets demonstrates a large overlap across a wide range of environmental stresses. Interestingly, RWR genes also exhibit a striking level and pattern of circadian regulation, with induced and repressed genes displaying antiphasic rhythms. Using bioinformatic analysis, we identified a novel motif overrepresented in the promoters of RWR genes, herein designated as the Rapid Stress Response Element (RSRE). We demonstrate in transgenic plants that multimerized RSREs are sufficient to confer a rapid response to both biotic and abiotic stresses in vivo, thereby establishing the functional involvement of this motif in primary transcriptional stress responses. Collectively, our data provide evidence for a novel cis-element that is distributed across the promoters of an array of diverse stress-responsive genes, poised to respond immediately and coordinately to stress signals. This structure suggests that plants may have a transcriptional network resembling the general stress signaling pathway in yeast and that the RSRE element may provide the key to this coordinate regulation. PMID:17953483

Computational prediction and experimental verification of HVA1-like abscisic acid responsive promoters in rice (Oryza sativa).

PubMed

Ross, Christian; Shen, Qingxi J

2006-09-01

Abscisic acid (ABA) is one of the central plant hormones, responsible for controlling both maturation and germination in seeds, as well as mediating adaptive responses to desiccation, injury, and pathogen infection in vegetative tissues. Thorough analyses of two barley genes, HVA1 and HVA22, indicate that their response to ABA relies on the interaction of two cis-acting elements in their promoters, an ABA response element (ABRE) and a coupling element (CE). Together, they form an ABA response promoter complex (ABRC). Comparison of promoters of barley HVA1 and it rice orthologue indicates that the structures and sequences of their ABRCs are highly similar. Prediction of ABA responsive genes in the rice genome is then tractable to a bioinformatics approach based on the structures of the well-defined barley ABRCs. Here we describe a model developed based on the consensus, inter-element spacing and orientations of experimentally determined ABREs and CEs. Our search of the rice promoter database for promoters that fit the model has generated a partial list of genes in rice that have a high likelihood of being involved in the ABA signaling network. The ABA inducibility of some of the rice genes identified was validated with quantitative reverse transcription PCR (QPCR). By limiting our input data to known enhancer modules and experimentally derived rules, we have generated a high confidence subset of ABA-regulated genes. The results suggest that the pathways by which cereals respond to biotic and abiotic stresses overlap significantly, and that regulation is not confined to the level transcription. The large fraction of putative regulatory genes carrying HVA1-like enhancer modules in their promoters suggests the ABA signal enters at multiple points into a complex regulatory network that remains largely unmapped.

Amino Acid Change in the Carbohydrate Response Element Binding Protein is associated with lower triglycerides and myocardial infarction incidence depending on level of adherence to the Mediterranean diet in the PREDIMED trial

USDA-ARS?s Scientific Manuscript database

A variant (rs3812316, C771G, and Gln241His) in the MLXIPL (Max-like protein X interacting protein-like) gene encoding the carbohydrate response element binding protein has been associated with lower triglycerides. However, its association with cardiovascular diseases and gene-diet interactions modul...

Spatial Memory in the Morris Water Maze and Activation of Cyclic AMP Response Element-Binding (CREB) Protein within the Mouse Hippocampus

ERIC Educational Resources Information Center

Porte, Yves; Buhot, Marie Christine; Mons, Nicole E.

2008-01-01

We investigated the spatio-temporal dynamics of learning-induced cAMP response element-binding protein activation/phosphorylation (pCREB) in mice trained in a spatial reference memory task in the water maze. Using immunohistochemistry, we examined pCREB immunoreactivity (pCREB-ir) in hippocampal CA1 and CA3 and related brain structures. During the…

40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 29 2012-07-01 2012-07-01 false Form: Application for Reimbursement to... RESPONSE TO HAZARDOUS SUBSTANCE RELEASES Pt. 310, App. III Appendix III to Part 310—Form: Application for... ER18FE98.000 ER18FE98.001 Attachment 1 to Form 9310-1 Cost Element Codes and Comments [Cost Element Codes...

40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 28 2014-07-01 2014-07-01 false Form: Application for Reimbursement to... RESPONSE TO HAZARDOUS SUBSTANCE RELEASES Pt. 310, App. III Appendix III to Part 310—Form: Application for... ER18FE98.000 ER18FE98.001 Attachment 1 to Form 9310-1 Cost Element Codes and Comments [Cost Element Codes...

40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 29 2013-07-01 2013-07-01 false Form: Application for Reimbursement to... RESPONSE TO HAZARDOUS SUBSTANCE RELEASES Pt. 310, App. III Appendix III to Part 310—Form: Application for... ER18FE98.000 ER18FE98.001 Attachment 1 to Form 9310-1 Cost Element Codes and Comments [Cost Element Codes...

Nonlinear dynamic modeling of surface defects in rolling element bearing systems

NASA Astrophysics Data System (ADS)

Rafsanjani, Ahmad; Abbasion, Saeed; Farshidianfar, Anoushiravan; Moeenfard, Hamid

2009-01-01

In this paper an analytical model is proposed to study the nonlinear dynamic behavior of rolling element bearing systems including surface defects. Various surface defects due to local imperfections on raceways and rolling elements are introduced to the proposed model. The contact force of each rolling element described according to nonlinear Hertzian contact deformation and the effect of internal radial clearance has been taken into account. Mathematical expressions were derived for inner race, outer race and rolling element local defects. To overcome the strong nonlinearity of the governing equations of motion, a modified Newmark time integration technique was used to solve the equations of motion numerically. The results were obtained in the form of time series, frequency responses and phase trajectories. The validity of the proposed model verified by comparison of frequency components of the system response with those obtained from experiments. The classical Floquet theory has been applied to the proposed model to investigate the linear stability of the defective bearing rotor systems as the parameters of the system changes. The peak-to-peak frequency response of the system for each case is obtained and the basic routes to periodic, quasi-periodic and chaotic motions for different internal radial clearances are determined. The current study provides a powerful tool for design and health monitoring of machine systems.

In situ calibration of atmospheric-infrasound sensors including the effects of wind-noise-reduction pipe systems.

PubMed

Gabrielson, Thomas B

2011-09-01

A worldwide network of more than 40 infrasound monitoring stations has been established as part of the effort to ensure compliance with the Comprehensive Nuclear Test Ban Treaty. Each station has four to eight individual infrasound elements in a kilometer-scale array for detection and bearing determination of acoustic events. The frequency range of interest covers a three-decade range-roughly from 0.01 to 10 Hz. A typical infrasound array element consists of a receiving transducer connected to a multiple-inlet pipe network to average spatially over the short-wavelength turbulence-associated "wind noise." Although the frequency response of the transducer itself may be known, the wind-noise reduction system modifies that response. In order to understand the system's impact on detection and identification of acoustical events, the overall frequency response must be determined. This paper describes a technique for measuring the absolute magnitude and phase of the frequency response of an infrasound element including the wind-noise-reduction piping by comparison calibration using ambient noise and a reference-microphone system. Measured coherence between the reference and the infrasound element and the consistency between the magnitude and the phase provide quality checks on the process. © 2011 Acoustical Society of America

Small RNAs, big impact: small RNA pathways in transposon control and their effect on the host stress response.

PubMed

Wheeler, Bayly S

2013-12-01

Transposons are mobile genetic elements that are a major constituent of most genomes. Organisms regulate transposable element expression, transposition, and insertion site preference, mitigating the genome instability caused by uncontrolled transposition. A recent burst of research has demonstrated the critical role of small non-coding RNAs in regulating transposition in fungi, plants, and animals. While mechanistically distinct, these pathways work through a conserved paradigm. The presence of a transposon is communicated by the presence of its RNA or by its integration into specific genomic loci. These signals are then translated into small non-coding RNAs that guide epigenetic modifications and gene silencing back to the transposon. In addition to being regulated by the host, transposable elements are themselves capable of influencing host gene expression. Transposon expression is responsive to environmental signals, and many transposons are activated by various cellular stresses. TEs can confer local gene regulation by acting as enhancers and can also confer global gene regulation through their non-coding RNAs. Thus, transposable elements can act as stress-responsive regulators that control host gene expression in cis and trans.

Uncertainty quantification for complex systems with very high dimensional response using Grassmann manifold variations

NASA Astrophysics Data System (ADS)

Giovanis, D. G.; Shields, M. D.

2018-07-01

This paper addresses uncertainty quantification (UQ) for problems where scalar (or low-dimensional vector) response quantities are insufficient and, instead, full-field (very high-dimensional) responses are of interest. To do so, an adaptive stochastic simulation-based methodology is introduced that refines the probability space based on Grassmann manifold variations. The proposed method has a multi-element character discretizing the probability space into simplex elements using a Delaunay triangulation. For every simplex, the high-dimensional solutions corresponding to its vertices (sample points) are projected onto the Grassmann manifold. The pairwise distances between these points are calculated using appropriately defined metrics and the elements with large total distance are sub-sampled and refined. As a result, regions of the probability space that produce significant changes in the full-field solution are accurately resolved. An added benefit is that an approximation of the solution within each element can be obtained by interpolation on the Grassmann manifold. The method is applied to study the probability of shear band formation in a bulk metallic glass using the shear transformation zone theory.

A HLA class I cis-regulatory element whose activity can be modulated by hormones.

PubMed

Sim, B C; Hui, K M

1994-12-01

To elucidate the basis of the down-regulation in major histocompatibility complex (MHC) class I gene expression and to identify possible DNA-binding regulatory elements that have the potential to interact with class I MHC genes, we have studied the transcriptional regulation of class I HLA genes in human breast carcinoma cells. A 9 base pair (bp) negative cis-regulatory element (NRE) has been identified using band-shift assays employing DNA sequences derived from the 5'-flanking region of HLA class I genes. This 9-bp element, GTCATGGCG, located within exon I of the HLA class I gene, can potently inhibit the expression of a heterologous thymidine kinase (TK) gene promoter and the HLA enhancer element. Furthermore, this regulatory element can exert its suppressive function in either the sense or anti-sense orientation. More interestingly, NRE can suppress dexamethasone-mediated gene activation in the context of the reported glucocorticoid-responsive element (GRE) in MCF-7 cells but has no influence on the estrogen-mediated transcriptional activation of MCF-7 cells in the context of the reported estrogen-responsive element (ERE). Furthermore, the presence of such a regulatory element within the HLA class I gene whose activity can be modulated by hormones correlates well with our observation that the level of HLA class I gene expression can be down-regulated by hormones in human breast carcinoma cells. Such interactions between negative regulatory elements and specific hormone trans-activators are novel and suggest a versatile form of transcriptional control.

Open-water and under-ice seasonal variations in trace element content and physicochemical associations in fluvial bed sediment.

PubMed

Doig, Lorne E; Carr, Meghan K; Meissner, Anna G N; Jardine, Tim D; Jones, Paul D; Bharadwaj, Lalita; Lindenschmidt, Karl-Erich

2017-11-01

Across the circumpolar world, intensive anthropogenic activities in the southern reaches of many large, northward-flowing rivers can cause sediment contamination in the downstream depositional environment. The influence of ice cover on concentrations of inorganic contaminants in bed sediment (i.e., sediment quality) is unknown in these rivers, where winter is the dominant season. A geomorphic response unit approach was used to select hydraulically diverse sampling sites across a northern test-case system, the Slave River and delta (Northwest Territories, Canada). Surface sediment samples (top 1 cm) were collected from 6 predefined geomorphic response units (12 sites) to assess the relationships between bed sediment physicochemistry (particle size distribution and total organic carbon content) and trace element content (mercury and 18 other trace elements) during open-water conditions. A subset of sites was resampled under-ice to assess the influence of season on these relationships and on total trace element content. Concentrations of the majority of trace elements were strongly correlated with percent fines and proxies for grain size (aluminum and iron), with similar trace element grain size/grain size proxy relationships between seasons. However, finer materials were deposited under ice with associated increases in sediment total organic carbon content and the concentrations of most trace elements investigated. The geomorphic response unit approach was effective at identifying diverse hydrological environments for sampling prior to field operations. Our data demonstrate the need for under-ice sampling to confirm year-round consistency in trace element-geochemical relationships in fluvial systems and to define the upper extremes of these relationships. Whether contaminated or not, under-ice bed sediment can represent a "worst-case" scenario in terms of trace element concentrations and exposure for sediment-associated organisms in northern fluvial systems. Environ Toxicol Chem 2017;36:2916-2924. © 2017 SETAC. © 2017 SETAC.

Finite element, modal co-ordinate analysis of structures subjected to moving loads

NASA Astrophysics Data System (ADS)

Olsson, M.

1985-03-01

Some of the possibilities of the finite element method in the moving load problem are demonstrated. The bridge-vehicle interaction phenomenon is considered by deriving a general bridge-vehicle element which is believed to be novel. This element may be regarded as a finite element with time-dependent and unsymmetric element matrices. The bridge response is formulated in modal co-ordinates thereby reducing the number of equations to be solved within each time step. Illustrative examples are shown for the special case of a beam bridge model and a one-axle vehicle model.

Analysis of Resonance Response Performance of C-Band Antenna Using Parasitic Element

PubMed Central

Islam, M. T.; Misran, N.; Mandeep, J. S.

2014-01-01

Analysis of the resonance response improvement of a planar C-band (4–8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency. PMID:24895643

Superheavy Elements

ERIC Educational Resources Information Center

Tsang, Chin Fu

1975-01-01

Discusses the possibility of creating elements with an atomic number of around 114. Describes the underlying physics responsible for the limited extent of the periodic table and enumerates problems that must be overcome in creating a superheavy nucleus. (GS)

Statins Increase Plasminogen Activator Inhibitor Type 1 Gene Transcription through a Pregnane X Receptor Regulated Element

PubMed Central

Stanley, Frederick M.; Linder, Kathryn M.; Cardozo, Timothy J.

2015-01-01

Plasminogen activator inhibitor type 1 (PAI-1) is a multifunctional protein that has important roles in inflammation and wound healing. Its aberrant regulation may contribute to many disease processes such as heart disease. The PAI-1 promoter is responsive to multiple inputs including cytokines, growth factors, steroids and oxidative stress. The statin drugs, atorvastatin, mevastatin and rosuvastatin, increased basal and stimulated expression of the PAI-1 promoter 3-fold. A statin-responsive, nuclear hormone response element was previously identified in the PAI-1 promoter, but it was incompletely characterized. We characterized this direct repeat (DR) of AGGTCA with a 3-nucleotide spacer at -269/-255 using deletion and directed mutagenesis. Deletion or mutation of this element increased basal transcription from the promoter suggesting that it repressed PAI-1 transcription in the unliganded state. The half-site spacing and the ligand specificity suggested that this might be a pregnane X receptor (PXR) responsive element. Computational molecular docking showed that atorvastatin, mevastatin and rosuvastatin were structurally compatible with the PXR ligand-binding pocket in its agonist conformation. Experiments with Gal4 DNA binding domain fusion proteins showed that Gal4-PXR was activated by statins while other DR + 3 binding nuclear receptor fusions were not. Overexpression of PXR further enhanced PAI-1 transcription in response to statins. Finally, ChIP experiments using Halo-tagged PXR and RXR demonstrated that both components of the PXR-RXR heterodimer bound to this region of the PAI-1 promoter. PMID:26379245

2D and 3D Multiscale/Multicomponent Modeling of Impact Response of Heterogeneous Energetic Composites

DTIC Science & Technology

2016-06-01

7 Development of Cohesive Finite Element Method (CFEM) Capability ................................7 3D...Cohesive Finite Element Method (CFEM) framework A new scientific framework and technical capability is developed for the computational analyses of...this section should shift from reporting activities to reporting accomplishments. Development of Cohesive Finite Element Method (CFEM) Capability

Elemental cycling response of an Adirondack subalpine spruce-fir forest to atmospheric and environmental change

Treesearch

Andrew J. Friedland; Eric K. Miller

1996-01-01

Patterns and trends in forest elemental cycling can become more apparent in the presence of atmospheric perturbations. High-elevation forests of the northeastern United States have received large amounts of atmospheric deposition of pollutants, which have altered natural elemental cycling and retention rates in a variety of ways. This study examined atmospheric...

Creating diversified response profiles from a single quenchometric sensor element by using phase-resolved luminescence.

PubMed

Tehan, Elizabeth C; Bukowski, Rachel M; Chodavarapu, Vamsy P; Titus, Albert H; Cartwright, Alexander N; Bright, Frank V

2015-01-05

We report a new strategy for generating a continuum of response profiles from a single luminescence-based sensor element by using phase-resolved detection. This strategy yields reliable responses that depend in a predictable manner on changes in the luminescent reporter lifetime in the presence of the target analyte, the excitation modulation frequency, and the detector (lock-in amplifier) phase angle. In the traditional steady-state mode, the sensor that we evaluate exhibits a linear, positive going response to changes in the target analyte concentration. Under phase-resolved conditions the analyte-dependent response profiles: (i) can become highly non-linear; (ii) yield negative going responses; (iii) can be biphasic; and (iv) can exhibit super sensitivity (e.g., sensitivities up to 300 fold greater in comparison to steady-state conditions).

Two CGTCA motifs and a GHF1/Pit1 binding site mediate cAMP-dependent protein kinase A regulation of human growth hormone gene expression in rat anterior pituitary GC cells.

PubMed

Shepard, A R; Zhang, W; Eberhardt, N L

1994-01-21

We established the cis-acting elements which mediate cAMP responsiveness of the human growth hormone (hGH) gene in transiently transfected rat anterior pituitary tumor GC cells. Analysis of the intact hGH gene or hGH 5'-flanking DNA (5'-FR) coupled to the hGh cDNA or chloramphenicol acetyltransferase or luciferase genes, indicated that cAMP primarily stimulated hGH promoter activity. Cotransfection of a protein kinase A inhibitory protein cDNA demonstrated that the cAMP response was mediated by protein kinase A. Mutational analysis of the hGH promoter identified two core cAMP response element motifs (CGTCA) located at nucleotides -187/-183 (distal cAMP response element; dCRE) and -99/-95 (proximal cAMP response element; pCRE) and a pituitary-specific transcription factor (GHF1/Pit1) binding site at nucleotides -123/-112 (dGHF1) which were required for cAMP responsiveness. GHF1 was not a limiting factor, since overexpression of GHF1 in cotransfections increased basal but not forskolin induction levels. Gel shift analyses indicated that similar, ubiquitous, thermostable protein(s) specifically bound the pCRE and dCRE motifs. The CGTCA motif-binding factors were cAMP response element binding protein (CREB)/activating transcription factor-1 (ATF-1)-related, since the DNA-protein complex was competed by unlabeled CREB consensus oligonucleotide, specifically supershifted by antisera to CREB and ATF-1 but not ATF-2, and was bound by purified CREB with the same relative binding affinity (pCRE < dCRE < CREB) and mobility as the GC nuclear extract. UV cross-linking and Southwestern blot analyses revealed multiple DNA-protein interactions of which approximately 100- and approximately 45-kDa proteins were predominant; the approximately 45-kDa protein may represent CREB. These results indicate that CREB/ATF-1-related factors act coordinately with the cell-specific factor GHF1 to mediate cAMP-dependent regulation of hGH-1 gene transcription in anterior pituitary somatotrophs.

The effects of cyclic tensile strain on the organisation and expression of cytoskeletal elements in bovine intervertebral disc cells: an in vitro study.

PubMed

Li, S; Jia, X; Duance, V C; Blain, E J

2011-06-20

It is still relatively unclear how intervertebral disc (IVD) cells sense a mechanical stimulus and convert this signal into a biochemical response. Previous studies demonstrated that the cytoskeletal elements are mechano-responsive in many cell types and may contribute to mechano-signalling pathways. The objective of this study was to determine the response of cells from the outer annulus fibrosus (OAF) to physiological levels of cyclic tensile strain; further, cells from the nucleus pulposus (NP) were also subjected to an identical loading regime to compare biological responses across the IVD populations. We determined whether the organisation and expression of the major cytoskeletal elements and their associated accessory proteins are responsive to mechanical stimulation in these cells, and whether these changes correlated with either a catabolic or anabolic phenotype. OAF and NP cells from immature bovine IVD were seeded onto Flexcell® type I collagen coated plates. Cells were subjected to cyclic tensile strain (10 %, 1 Hz) for 60 minutes. Post-loading, cells were processed for immunofluorescence microscopy, RNA extracted for quantitative PCR and protein extracted for Western blotting analysis. F-actin reorganisation was evident in OAF and NP cells subjected to tensile strain; strain induced β-actin at the transcriptional and translational level in OAF cells. β-tubulin mRNA and protein synthesis increased in strained OAF cells, but vimentin expression was significantly inhibited. Cytoskeletal element organisation and expression were less responsive to strain in NP cells. Tensile strain increased type I collagen and differentially regulated extracellular matrix (ECM)-degrading enzymes' mRNA levels in OAF cells. Strain induced type II collagen transcription in NP cells, but had no effect on the transcription of any other genes analysed. Tensile strain induces different mechano-responses in the organisation and/or expression of cytoskeletal elements and on markers of IVD metabolism. Differential mechano-regulation of anabolic and catabolic ECM components in the OAF and NP populations reflects their respective mechanical environments in situ.

Modeling the hydro-mechanical responses of strip and circular punch loadings on water-saturated collapsible geomaterials

DOE PAGES

Sun, WaiChing; Chen, Qiushi; Ostien, Jakob T.

2013-11-22

A stabilized enhanced strain finite element procedure for poromechanics is fully integrated with an elasto-plastic cap model to simulate the hydro-mechanical interactions of fluid-infiltrating porous rocks with associative and non-associative plastic flow. We present a quantitative analysis on how macroscopic plastic volumetric response caused by pore collapse and grain rearrangement affects the seepage of pore fluid, and vice versa. Results of finite element simulations imply that the dissipation of excess pore pressure may significantly affect the stress path and thus alter the volumetric plastic responses.

A magnetostatic-coupling based remote query sensor for environmental monitoring

NASA Technical Reports Server (NTRS)

Grimes, C. A.; Stoyanov, P. G.; Liu, Y.; Tong, C.; Ong, K. G.; Loiselle, K.; Shaw, M.; Doherty, S. A.; Seitz, W. R.

1999-01-01

A new type of in situ, remotely monitored magnetism-based sensor is presented that is comprised of an array of magnetically soft, magnetostatically-coupled ferromagnetic thin-film elements or particles combined with a chemically responsive material that swells or shrinks in response to the analyte of interest. As the chemically responsive material changes size the distance between the ferromagnetic elements changes, altering the inter-element magnetostatic coupling. This in turn changes the coercive force of the sensor, the amplitude of the voltage spikes detected in nearby pick-up coils upon magnetization reversal and the number of higher-order harmonics generated by the flux reversal. Since the sensor is monitored through changes in magnetic flux, no physical connections such as wires or cables are needed to obtain sensor information, nor is line of sight alignment required as with laser telemetry; the sensors can be detected from within sealed, opaque or thin metallic enclosures.

A distal ABA responsive element in AtNCED3 promoter is required for positive feedback regulation of ABA biosynthesis in Arabidopsis.

PubMed

Yang, Yan-Zhuo; Tan, Bao-Cai

2014-01-01

The plant hormone abscisic acid (ABA) plays a crucial role in plant development and responses to abiotic stresses. Recent studies indicate that a positive feedback regulation by ABA exists in ABA biosynthesis in plants under dehydration stress. To understand the molecular basis of this regulation, we analyzed the cis-elements of the AtNCED3 promoter in Arabidopsis. AtNCED3 encodes the first committed and highly regulated dioxygenase in the ABA biosynthetic pathway. Through delineated and mutagenesis analyses in stable-transformed Arabidopsis, we revealed that a distal ABA responsive element (ABRE: GGCACGTG, -2372 to -2364 bp) is required for ABA-induced AtNCED3 expression. By analyzing the AtNCED3 expression in ABRE binding protein ABF3 over-expression transgenic plants and knock-out mutants, we provide evidence that the ABA feedback regulation of AtNCED3 expression is not mediated by ABF3.

Signaling cross-talk between peroxisome proliferator-activated receptor/retinoid X receptor and estrogen receptor through estrogen response elements.

PubMed

Keller, H; Givel, F; Perroud, M; Wahli, W

1995-07-01

Peroxisome proliferator-activated receptors (PPARs) and retinoid X receptors (RXRs) are nuclear hormone receptors that are activated by fatty acids and 9-cis-retinoic acid, respectively. PPARs and RXRs form heterodimers that activate transcription by binding to PPAR response elements (PPREs) in the promoter of target genes. The PPREs described thus far consist of a direct tandem repeat of the AGGTCA core element with one intervening nucleotide. We show here that the vitellogenin A2 estrogen response element (ERE) can also function as a PPRE and is bound by a PPAR/RXR heterodimer. Although this heterodimer can bind to several other ERE-related palindromic response elements containing AGGTCA half-sites, only the ERE is able to confer transactivation of test reporter plasmids, when the ERE is placed either close to or at a distance from the transcription initiation site. Examination of natural ERE-containing promoters, including the pS2, very-low-density apolipoprotein II and vitellogenin A2 genes, revealed considerable differences in the binding of PPAR/RXR heterodimers to these EREs. In their natural promoter context, these EREs did not allow transcriptional activation by PPARs/RXRs. Analysis of this lack of stimulation of the vitellogenin A2 promoter demonstrated that PPARs/RXRs bind to the ERE but cannot transactivate due to a nonpermissive promoter structure. As a consequence, PPARs/RXRs inhibit transactivation by the estrogen receptor through competition for ERE binding. This is the first example of signaling cross-talk between PPAR/RXR and estrogen receptor.

Modulation of hepatocyte growth factor gene expression by estrogen in mouse ovary.

PubMed

Liu, Y; Lin, L; Zarnegar, R

1994-09-01

Hepatocyte growth factor (HGF) is expressed in a variety of tissues and cell types under normal conditions and in response to various stimuli such as tissue injury. In the present study, we demonstrate that the transcription of the HGF gene is stimulated by estrogen in mouse ovary. A single injection of 17 beta-estradiol results in a dramatic and transient elevation of the levels of mouse HGF mRNA. Sequence analysis has found that two putative estrogen responsive elements (ERE) reside at -872 in the 5'-flanking region and at +511 in the first intron, respectively, of the mouse HGF gene. To test whether these ERE elements are responsible for estrogen induction of HGF gene expression, chimeric plasmids containing variable regions of the 5'-flanking sequence of HGF gene and the coding region for chloramphenicol acetyltransferase (CAT) gene were transiently transfected into both human endometrial carcinoma RL 95-2 cells and mouse fibroblast NIH 3T3 cells to assess hormone responsiveness. Transfection results indicate that the ERE elements of the mouse HGF gene can confer estrogen action to either homologous or heterologous promoters. Nuclear protein extracts either from RL95-2 cells transfected with the estrogen receptor expression vector or from mouse liver bound in vitro to ERE elements specifically, as shown by band shift assay. Therefore, our results demonstrate that the HGF gene is transcriptionally regulated by estrogen in mouse ovary; and such regulation is mediated via a direct interaction of the estrogen receptor complex with cis-acting ERE elements identified in the mouse HGF gene.

Functional consequences of inducible genetic elements from the p53 SOS response in a mammalian organ system.

PubMed

Guthrie, O'neil W

2017-10-01

In response to DNA damage from ultraviolet (UV) radiation, bacteria deploy the SOS response in order to limit cell death. This bacterial SOS response is characterized by an increase in the recA gene that transactivates expression of multiple DNA repair genes. The current series of experiments demonstrate that a mammalian organ system (the cochlea) that is not evolutionarily conditioned to UV radiation can elicit SOS responses that are reminiscent of that of bacteria. This mammalian SOS response is characterized by an increase in the p53 gene with activation of multiple DNA repair genes that harbor p53 response elements in their promoters. Furthermore, the experimental results provide support for the notion of a convergent trigger paradox, where independent SOS triggers facilitate disparate physiologic sequelae (loss vs. recovery of function). Therefore, it is proposed that the mammalian SOS response is multifunctional and manipulation of this endogenous response could be exploited in future biomedical interventions. Copyright © 2017 Elsevier Inc. All rights reserved.

MNL1 Regulates Weak Acid–induced Stress Responses of the Fungal Pathogen Candida albicans

PubMed Central

Selway, Laura; Stead, David; Walker, Jan; Yin, Zhikang; Nicholls, Susan M.; Crowe, Jonathan; Sheils, Emma M.; Brown, Alistair J.P.

2008-01-01

MNL1, the Candida albicans homologue of an orphan Msn2-like gene (YER130c in Saccharomyces cerevisiae) has no known function. Here we report that MNL1 regulates weak acid stress responses. Deletion of MNL1 prevents the long-term adaptation of C. albicans cells to weak acid stresses and compromises their global transcriptional response under these conditions. The promoters of Mnl1-dependent genes contain a novel STRE-like element (SLE) that imposes Mnl1-dependent, weak acid stress–induced transcription upon a lacZ reporter in C. albicans. The SLE (HHYYCCCCTTYTY) is related to the Nrg1 response element (NRE) element recognized by the transcriptional repressor Nrg1. Deletion of NRG1 partially restores the ability of C. albicans mnl1 cells to adapt to weak acid stress, indicating that Mnl1 and Nrg1 act antagonistically to regulate this response. Molecular, microarray, and proteomic analyses revealed that Mnl1-dependent adaptation does not occur in cells exposed to proapoptotic or pronecrotic doses of weak acid, suggesting that Ras-pathway activation might suppress the Mnl1-dependent weak acid response in dying cells. Our work defines a role for this YER130c orthologue in stress adaptation and cell death. PMID:18653474

ABFs, a family of ABA-responsive element binding factors.

PubMed

Choi, H; Hong, J; Ha, J; Kang, J; Kim, S Y

2000-01-21

Abscisic acid (ABA) plays an important role in environmental stress responses of higher plants during vegetative growth. One of the ABA-mediated responses is the induced expression of a large number of genes, which is mediated by cis-regulatory elements known as abscisic acid-responsive elements (ABREs). Although a number of ABRE binding transcription factors have been known, they are not specifically from vegetative tissues under induced conditions. Considering the tissue specificity of ABA signaling pathways, factors mediating ABA-dependent stress responses during vegetative growth phase may thus have been unidentified so far. Here, we report a family of ABRE binding factors isolated from young Arabidopsis plants under stress conditions. The factors, isolated by a yeast one-hybrid system using a prototypical ABRE and named as ABFs (ABRE binding factors) belong to a distinct subfamily of bZIP proteins. Binding site selection assay performed with one ABF showed that its preferred binding site is the strong ABRE, CACGTGGC. ABFs can transactivate an ABRE-containing reporter gene in yeast. Expression of ABFs is induced by ABA and various stress treatments, whereas their induction patterns are different from one another. Thus, a new family of ABRE binding factors indeed exists that have the potential to activate a large number of ABA/stress-responsive genes in Arabidopsis.

Densely ionizing radiation affects DNA methylation of selective LINE-1 elements1

PubMed Central

Prior, Sara; Miousse, Isabelle R.; Nzabarushimana, Etienne; Pathak, Rupak; Skinner, Charles; Kutanzi, Kristy R.; Allen, Antiño R.; Raber, Jacob; Tackett, Alan J.; Hauer-Jensen, Martin; Nelson, Gregory A.; Koturbash, Igor

2016-01-01

Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2′-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promoter type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5′-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR. PMID:27419368

The Interaction of Genotype and Environment Determines Variation in the Maize Kernel Ionome

PubMed Central

Asaro, Alexandra; Ziegler, Gregory; Ziyomo, Cathrine; Hoekenga, Owen A.; Dilkes, Brian P.; Baxter, Ivan

2016-01-01

Plants obtain soil-resident elements that support growth and metabolism from the water-flow facilitated by transpiration and active transport processes. The availability of elements in the environment interacts with the genetic capacity of organisms to modulate element uptake through plastic adaptive responses, such as homeostasis. These interactions should cause the elemental contents of plants to vary such that the effects of genetic polymorphisms will be dramatically dependent on the environment in which the plant is grown. To investigate genotype by environment interactions underlying elemental accumulation, we analyzed levels of elements in maize kernels of the Intermated B73 × Mo17 (IBM) recombinant inbred population grown in 10 different environments, spanning a total of six locations and five different years. In analyses conducted separately for each environment, we identified a total of 79 quantitative trait loci (QTL) controlling seed elemental accumulation. While a set of these QTL was found in multiple environments, the majority were specific to a single environment, suggesting the presence of genetic by environment interactions. To specifically identify and quantify QTL by environment interactions (QEIs), we implemented two methods: linear modeling with environmental covariates, and QTL analysis on trait differences between growouts. With these approaches, we found several instances of QEI, indicating that elemental profiles are highly heritable, interrelated, and responsive to the environment. PMID:27770027

The Interaction of Genotype and Environment Determines Variation in the Maize Kernel Ionome.

PubMed

Asaro, Alexandra; Ziegler, Gregory; Ziyomo, Cathrine; Hoekenga, Owen A; Dilkes, Brian P; Baxter, Ivan

2016-12-07

Plants obtain soil-resident elements that support growth and metabolism from the water-flow facilitated by transpiration and active transport processes. The availability of elements in the environment interacts with the genetic capacity of organisms to modulate element uptake through plastic adaptive responses, such as homeostasis. These interactions should cause the elemental contents of plants to vary such that the effects of genetic polymorphisms will be dramatically dependent on the environment in which the plant is grown. To investigate genotype by environment interactions underlying elemental accumulation, we analyzed levels of elements in maize kernels of the Intermated B73 × Mo17 (IBM) recombinant inbred population grown in 10 different environments, spanning a total of six locations and five different years. In analyses conducted separately for each environment, we identified a total of 79 quantitative trait loci (QTL) controlling seed elemental accumulation. While a set of these QTL was found in multiple environments, the majority were specific to a single environment, suggesting the presence of genetic by environment interactions. To specifically identify and quantify QTL by environment interactions (QEIs), we implemented two methods: linear modeling with environmental covariates, and QTL analysis on trait differences between growouts. With these approaches, we found several instances of QEI, indicating that elemental profiles are highly heritable, interrelated, and responsive to the environment. Copyright © 2016 Asaro et al.

Dehydration-induced WRKY genes from tobacco and soybean respond to jasmonic acid treatments in BY-2 cell culture.

PubMed

Rabara, Roel C; Tripathi, Prateek; Lin, Jun; Rushton, Paul J

2013-02-15

Drought is one of the important environmental factors affecting crop production worldwide and therefore understanding the molecular response of plant to stress is an important step in crop improvement. WRKY transcription factors are one of the 10 largest transcription factor families across the green lineage. In this study, highly upregulated dehydration-induced WRKY and enzyme-coding genes from tobacco and soybean were selected from microarray data for promoter analyses. Putative stress-related cis-regulatory elements such as TGACG motif, ABRE-like elements; W and G-like sequences were identified by an in silico analyses of promoter region of the selected genes. GFP quantification of transgenic BY-2 cell culture showed these promoters direct higher expression in-response to 100 μM JA treatment compared to 100 μM ABA, 10% PEG and 85 mM NaCl treatments. Thus promoter activity upon JA treatment and enrichment of MeJA-responsive elements in the promoter of the selected genes provides insights for these genes to be jasmonic acid responsive with potential of mediating cross-talk during dehydration responses. Copyright © 2013 Elsevier Inc. All rights reserved.

Elimination of active tad elements during the sexual phase of the Neurospora crassa life cycle.

PubMed

Anderson, C; Tang, Q; Kinsey, J A

2001-06-01

Tad is an active LINE-like retrotransposon isolated from the Adiopodoumé strain of Neurospora crassa. Extensive analysis of other Neurospora strains has revealed no other strain with active Tad, but all strains tested have multiple copies of defective Tad elements. We have examined the ability of Tad to survive during the sexual cycle of Neurospora and find that active Tad is rapidly eliminated. The characteristics of this elimination suggest that the repeat-induced point mutation (RIP) mechanism was responsible. By the use of transformation to switch the mating type of the Adiopodoumé strain we concluded that this strain is not defective in the RIP process. Analysis of defective Tad elements isolated from a variety of strains indicates that the major difference between these elements and active Tad is due to the presence of a large number of G-C to A-T transition mutations. This would be expected if the changes were due primarily to the RIP process. Mapping of a selection of defective Tad elements reveals that they are present on all of the chromosomes; however, many of the elements are not widely shared among strains. This suggests that repeated introduction and elimination of Tad elements has occurred. Mechanisms that might be responsible for this repeated introduction are discussed. Copyright 2001 Academic Press.

Predictions of the electro-mechanical response of conductive CNT-polymer composites

NASA Astrophysics Data System (ADS)

Matos, Miguel A. S.; Tagarielli, Vito L.; Baiz-Villafranca, Pedro M.; Pinho, Silvestre T.

2018-05-01

We present finite element simulations to predict the conductivity, elastic response and strain-sensing capability of conductive composites comprising a polymeric matrix and carbon nanotubes. Realistic representative volume elements (RVE) of the microstructure are generated and both constituents are modelled as linear elastic solids, with resistivity independent of strain; the electrical contact between nanotubes is represented by a new element which accounts for quantum tunnelling effects and captures the sensitivity of conductivity to separation. Monte Carlo simulations are conducted and the sensitivity of the predictions to RVE size is explored. Predictions of modulus and conductivity are found in good agreement with published results. The strain-sensing capability of the material is explored for multiaxial strain states.

The Pioneer Projects - Economical exploration of the solar system

NASA Technical Reports Server (NTRS)

Spahr, J. R.; Hall, C. F.

1975-01-01

The interplanetary Pioneer missions are reviewed in terms of management implications and cost control. The responsibilities, organizational structure, and management practices of the Pioneer Projects are presented. The lines of authority and areas of responsibility of the principal organizational elements supporting the Pioneer missions are identified, and the methods employed for maintaining effective and timely interactions among these elements are indicated. The technical and administrative functions of various organizational elements of the project are described. The management and control of activities prior to and during the hardware procurement phase are described to indicate the basis for obtaining visibility of the technical progress, utilization of resources, and cost performance of the contractors and other institutions supporting the Pioneer projects.

Mixed formulation for seismic analysis of composite steel-concrete frame structures

NASA Astrophysics Data System (ADS)

Ayoub, Ashraf Salah Eldin

This study presents a new finite element model for the nonlinear analysis of structures made up of steel and concrete under monotonic and cyclic loads. The new formulation is based on a two-field mixed formulation. In the formulation, both forces and deformations are simultaneously approximated within the element through independent interpolation functions. The main advantages of the model is the accuracy in global and local response with very few elements while maintaining rapid numerical convergence and robustness even under severe cyclic loading. Overall four elements were developed based on the new formulation: an element that describes the behavior of anchored reinforcing bars, an element that describes the behavior of composite steel-concrete beams with deformable shear connectors, an element that describes the behavior of reinforced concrete beam-columns with bond-slip, and an element that describes the behavior of pretensioned or posttensioned, bonded or unbonded prestressed concrete structures. The models use fiber discretization of beam sections to describe nonlinear material response. The transfer of forces between steel and concrete is described with bond elements. Bond elements are modeled with distributed spring elements. The non-linear behavior of the composite element derives entirely from the constitutive laws of the steel, concrete and bond elements. Two additional elements are used for the prestressed concrete models, a friction element that models the effect of friction between the tendon and the duct during the posttensioning operation, and an anchorage element that describes the behavior of the prestressing tendon anchorage in posttensioned structures. Two algorithms for the numerical implementation of the new proposed model are presented; an algorithm that enforces stress continuity at element boundaries, and an algorithm in which stress continuity is relaxed locally inside the element. Stability of both algorithms is discussed. Comparison with standard displacement based models and earlier flexibility based models is presented through numerical studies. The studies prove the superiority of the mixed model over both displacement and flexibility models. Correlation studies of the proposed model with experimental results of structural specimens are conducted. The studies show the accuracy of the model and its numerical robustness even under severe cyclic loading conditions.

Synthesis of a fiber-optic magnetostrictive sensor (FOMS) pixel for RF magnetic field imaging

NASA Astrophysics Data System (ADS)

Rengarajan, Suraj

The principal objective of this dissertation was to synthesize a sensor element with properties specifically optimized for integration into arrays capable of imaging RF magnetic fields. The dissertation problem was motivated by applications in nondestructive eddy current testing, smart skins, etc., requiring sensor elements that non-invasively detect millimeter-scale variations over several square meters, in low level magnetic fields varying at frequencies in the 100 kHz-1 GHz range. The poor spatial and temporal resolution of FOMS elements available prior to this dissertation research, precluded their use in non-invasive large area mapping applications. Prior research had been focused on large, discrete devices for detecting extremely low level magnetic fields varying at a few kHz. These devices are incompatible with array integration and imaging applications. The dissertation research sought to overcome the limitations of current technology by utilizing three new approaches; synthesizing magnetostrictive thin films and optimizing their properties for sensor applications, integrating small sensor elements into an array compatible fiber optic interferometer, and devising a RF mixing approach to measure high frequency magnetic fields using the integrated sensor element. Multilayer thin films were used to optimize the magnetic properties of the magnetostrictive elements. Alternating soft (Nisb{80}Fesb{20}) and hard (Cosb{50}Fesb{50}) magnetic alloy layers were selected for the multilayer and the layer thicknesses were varied to obtain films with a combination of large magnetization, high frequency permeability and large magnetostrictivity. X-Ray data and measurement of the variations in the magnetization, resistivity and magnetostriction with layer thicknesses, indicated that an interfacial layer was responsible for enhancing the sensing performance of the multilayers. A FOMS pixel was patterned directly onto the sensing arm of a fiber-optic interferometer, by sputtering a multilayer film with favorable sensor properties. After calibrating the interferometer response with a piezo, the mechanical and magnetic responses of the FOMS element were evaluated for various test fields. High frequency magnetic fields were detected using a local oscillator field to downconvert the RF signal fields to the lower mechanical resonant frequency of the element. A field sensitivity of 0.3 Oe/cm sensor element length was demonstrated at 1 MHz. A coherent magnetization rotation model was developed to predict the magnetostrictive response of the element, and identify approaches for optimizing its performance. This model predicts that an optimized element could resolve ˜1 mm variations in fields varying at frequencies >10 MHz with a sensitivity of ˜10sp{-3} Oe/mm. The results demonstrate the potential utility of integrating this device as a FOMS pixel in RF magnetic field imaging arrays.

Hypervelocity Impact Behaviour of CFRP-A1/HC Sandwich Panel: Finite-Element Studies

NASA Astrophysics Data System (ADS)

Phadnis, Vaibhav A.; Roy, Anish; Silberschmidt, Vadim V.

2014-06-01

The mechanical response of CFRP-Al/HC (carbon fibre- reinforced/epoxy composite face sheets with Al honeycomb core) sandwich panels to hyper-velocity impact ( 1 km/s) is studied using a finite-element model developed in ABAQUS/Explicit. The intraply damage of CFRP face sheets is analysed by the means of a user-defined material model (VUMAT) employing a combination of Hashin and Puck criteria and delamination is modelled using cohesive-zone elements. The damage of Al/HC core is assessed on the basis of a Johnson-Cook dynamic failure model while its hydrodynamic response is captured using the Mie- Gruneisen equation of state. The results obtained with the developed finite-element model showed a reasonable correlation to experimental damage patterns. The surface peeling of both face sheets was evident, with a significant delamination around the impact location accompanied by crushing of HC core.

Finite element analysis of hypervelocity impact behaviour of CFRP-Al/HC sandwich panel

NASA Astrophysics Data System (ADS)

Phadnis, Vaibhav A.; Silberschmidt, Vadim V.

2015-09-01

The mechanical response of CFRP-Al/HC (carbon fibre-reinforced/epoxy composite face sheets with Al honeycomb core) sandwich panels to hyper-velocity impact (up to 1 km/s) is studied using a finite-element model developed in ABAQUS/Explicit. The intraply damage of CFRP face sheets is analysed by mean of a user-defined material model (VUMAT) employing a combination of Hashin and Puck criteria, delamination modelled using cohesive-zone elements. The damaged Al/HC core is assessed on the basis of a Johnson Cook dynamic failure model while its hydrodynamic response is captured using the Mie-Gruneisen equation of state. The results obtained with the developed finite-element model showed a reasonable correlation to experimental damage patterns. The surface peeling of both face sheets was evident, with a significant delamination around the impact location accompanied by crushing HC core.

Vibration Response Models of a Stiffened Aluminum Plate Excited by a Shaker

NASA Technical Reports Server (NTRS)

Cabell, Randolph H.

2008-01-01

Numerical models of structural-acoustic interactions are of interest to aircraft designers and the space program. This paper describes a comparison between two energy finite element codes, a statistical energy analysis code, a structural finite element code, and the experimentally measured response of a stiffened aluminum plate excited by a shaker. Different methods for modeling the stiffeners and the power input from the shaker are discussed. The results show that the energy codes (energy finite element and statistical energy analysis) accurately predicted the measured mean square velocity of the plate. In addition, predictions from an energy finite element code had the best spatial correlation with measured velocities. However, predictions from a considerably simpler, single subsystem, statistical energy analysis model also correlated well with the spatial velocity distribution. The results highlight a need for further work to understand the relationship between modeling assumptions and the prediction results.

Finite element modeling of mitral leaflet tissue using a layered shell approximation

PubMed Central

Ratcliffe, Mark B.; Guccione, Julius M.

2012-01-01

The current study presents a finite element model of mitral leaflet tissue, which incorporates the anisotropic material response and approximates the layered structure. First, continuum mechanics and the theory of layered composites are used to develop an analytical representation of membrane stress in the leaflet material. This is done with an existing anisotropic constitutive law from literature. Then, the concept is implemented in a finite element (FE) model by overlapping and merging two layers of transversely isotropic membrane elements in LS-DYNA, which homogenizes the response. The FE model is then used to simulate various biaxial extension tests and out-of-plane pressure loading. Both the analytical and FE model show good agreement with experimental biaxial extension data, and show good mutual agreement. This confirms that the layered composite approximation presented in the current study is able to capture the exponential stiffening seen in both the circumferential and radial directions of mitral leaflets. PMID:22971896

Actuation method and apparatus, micropump, and PCR enhancement method

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

Ullakko, Kari; Mullner, Peter; Hampikian, Greg

An actuation apparatus includes at least one magnetic shape memory (MSM) element containing a material configured to expand and/or contract in response to exposure to a magnetic field. Among other things, the MSM element may be configured to pump fluid through a micropump by expanding and/or contracting in response to the magnetic field. The magnetic field may rotate about an axis of rotation and exhibit a distribution having a component substantially perpendicular to the axis of rotation. Further, the magnetic field distribution may include at least two components substantially orthogonal to one another lying in one or more planes perpendicularmore » to the axis of rotation. The at least one MSM element may contain nickel, manganese, and gallium. A polymerase chain reaction (PCR) may be enhanced by contacting a PCR reagent and DNA material with the MSM element.« less

Expansion and improvement of the FORMA system for response and load analysis. Volume 2C: Listings, finite element FORMA subroutines

NASA Technical Reports Server (NTRS)

Wohlen, R. L.

1976-01-01

A listing of the source deck of each finite element FORMA subroutine is given to remove the 'black-box' aura of the subroutines so that the analyst may better understand the detailed operations of each subroutine. The FORTRAN 4 programming language is used in all finite element FORMA subroutines.

A Uniform Approach to National Suicide Bomber Incident Response and Recovery

DTIC Science & Technology

2008-03-01

33 D. ELEMENTS OF MOTIVATION.................................................................35 E. THE TAMIL TIGER INFLUENCE...34 Ibid., 11. 35 Ibid., 8-12. 12 support of common objectives. Use of the Incident Command System (ICS) is an important element across multi... elements : • Initial strategic focus: to drive overt and covert United States forces from Muslim lands in the Near and Middle East. Covert American

Interagency partnering for weed prevention--progress on development of a National Early Detection and Rapid Response System for Invasive Plants in the United States

USGS Publications Warehouse

Westbrooks, R.; Westbrooks, R.

2011-01-01

Over the past 50 years, experience has shown that interagency groups provide an effective forum for addressing various invasive species issues and challenges on multiple land units. However, more importantly, they can also provide a coordinated framework for early detection, reporting, identification and vouchering, rapid assessment, and rapid response to new and emerging invasive plants in the United States. Interagency collaboration maximizes the use of available expertise, resources, and authority for promoting early detection and rapid response (EDRR) as the preferred management option for addressing new and emerging invasive plants. Currently, an interagency effort is underway to develop a National EDRR System for Invasive Plants in the United States. The proposed system will include structural and informational elements. Structural elements of the system include a network of interagency partner groups to facilitate early detection and rapid response to new invasive plants, including the Federal Interagency Committee for the Management of Noxious and Exotic Weeds (FICMNEW), State Invasive Species Councils, State Early Detection and Rapid Response Coordinating Committees, State Volunteer Detection and Reporting Networks, Invasive Plant Task Forces, and Cooperative Weed Management Areas. Informational elements and products being developed include Regional Invasive Plant Atlases, and EDRR Guidelines for EDRR Volunteer Network Training, Rapid Assessment and Rapid Response, and Criteria for Selection of EDRR Species. System science and technical support elements which are provided by cooperating state and federal scientists, include EDRR guidelines, training curriculum for EDRR volunteers and agency field personnel, plant identification and vouchering, rapid assessments, as well as predictive modeling and ecological range studies for invasive plant species.

n-Alkane and clofibrate, a peroxisome proliferator, activate transcription of ALK2 gene encoding cytochrome P450alk2 through distinct cis-acting promoter elements in Candida maltosa

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

Kogure, Takahisa; Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Higashijima 265-1, Niitsu, Niigata 956-8603; Takagi, Masamichi

2005-04-01

The ALK2 gene, encoding one of the n-alkane-hydroxylating cytochromes P450 in Candida maltosa, is induced by n-alkanes and a peroxisome proliferator, clofibrate. Deletion analysis of this gene's promoter revealed two cis-acting elements-an n-alkane-responsive element (ARE2) and a clofibrate-responsive element (CRE2)-that partly overlap in sequence but have distinct functions. ARE2-mediated activation responded to n-alkanes but not to clofibrate and was repressed by glucose. CRE2-mediated activation responded to polyunsaturated fatty acids and steroid hormones as well as to peroxisome proliferators but not to n-alkanes, and it was not repressed by glucose. Both elements mediated activation by oleic acid. Mutational analysis demonstrated thatmore » three CCG sequences in CRE2 were critical to the activation by clofibrate as well as to the in vitro binding of a specific protein to this element. These findings suggest that ALK2 is induced by peroxisome proliferators and steroid hormones through a specific CRE2-mediated regulatory mechanism.« less

48 CFR 19.602-1 - Referral.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SMALL BUSINESS PROGRAMS Certificates of Competency and Determinations of Responsibility 19.602-1... certain elements of responsibility (including, but not limited to, capability, competency, capacity...

Equivalent reduced model technique development for nonlinear system dynamic response

NASA Astrophysics Data System (ADS)

Thibault, Louis; Avitabile, Peter; Foley, Jason; Wolfson, Janet

2013-04-01

The dynamic response of structural systems commonly involves nonlinear effects. Often times, structural systems are made up of several components, whose individual behavior is essentially linear compared to the total assembled system. However, the assembly of linear components using highly nonlinear connection elements or contact regions causes the entire system to become nonlinear. Conventional transient nonlinear integration of the equations of motion can be extremely computationally intensive, especially when the finite element models describing the components are very large and detailed. In this work, the equivalent reduced model technique (ERMT) is developed to address complicated nonlinear contact problems. ERMT utilizes a highly accurate model reduction scheme, the System equivalent reduction expansion process (SEREP). Extremely reduced order models that provide dynamic characteristics of linear components, which are interconnected with highly nonlinear connection elements, are formulated with SEREP for the dynamic response evaluation using direct integration techniques. The full-space solution will be compared to the response obtained using drastically reduced models to make evident the usefulness of the technique for a variety of analytical cases.

Finite Element Analysis of Active and Sensory Thermopiezoelectric Composite Materials. Degree awarded by Northwestern Univ., Dec. 2000

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun

2001-01-01

Analytical formulations are developed to account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. The coupled response is captured at the material level through the thermopiezoelectric constitutive equations and leads to the inherent capability to model both the sensory and active responses of piezoelectric materials. A layerwise laminate theory is incorporated to provide more accurate analysis of the displacements, strains, stresses, electric fields, and thermal fields through-the-thickness. Thermal effects which arise from coefficient of thermal expansion mismatch, pyroelectric effects, and temperature dependent material properties are explicitly accounted for in the formulation. Corresponding finite element formulations are developed for piezoelectric beam, plate, and shell elements to provide a more generalized capability for the analysis of arbitrary piezoelectric composite structures. The accuracy of the current formulation is verified with comparisons from published experimental data and other analytical models. Additional numerical studies are also conducted to demonstrate additional capabilities of the formulation to represent the sensory and active behaviors. A future plan of experimental studies is provided to characterize the high temperature dynamic response of piezoelectric composite materials.

Element uptake and physiological responses of Lactuca sativa upon co-exposures to tourmaline and dissolved humic acids.

PubMed

Jia, Weili; Wang, Cuiping; Ma, Chuanxin; Wang, Jicheng; Sun, Hongwen

2018-06-01

Element migration and physiological response in Lactuca sativa upon co-exposure to tourmaline (T) and dissolved humic acids (DHAs) were investigated. Different fractions of DHA 1 and DHA 4 and three different doses of T were introduced into Hoagland's solution. The results indicated that T enhanced the contents of elements such as N and C, Si and Al in the roots and shoots. The correlation between TF values of Si and Al (R 2  = 0.7387) was higher than that of Si and Mn (R 2  = 0.4961) without the presence of DHAs. However, both DHA 1 and DHA 4 increased the correlation between Si and Mn, but decreased the one between Si and Al. CAT activities in T treatments were positively correlated to the contents of N and Al in the shoots, whose R 2 was 0.9994 and 0.9897, respectively. In the co-exposure of DHAs and tourmaline, DHA 4 exhibited more impacts on element uptake, CAT activities, as well as ABA contents in comparison with the presence of DHA 1 , regardless of the T exposure doses. These results suggested that DHAs have effects on mineral element behaviors and physiological response in Lactuca sativa upon exposure to tourmaline for the first time, which had great use in guiding soil remediation.

CELFE/NASTRAN Code for the Analysis of Structures Subjected to High Velocity Impact

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1978-01-01

CELFE (Coupled Eulerian Lagrangian Finite Element)/NASTRAN Code three-dimensional finite element code has the capability for analyzing of structures subjected to high velocity impact. The local response is predicted by CELFE and, for large problems, the far-field impact response is predicted by NASTRAN. The coupling of the CELFE code with NASTRAN (CELFE/NASTRAN code) and the application of the code to selected three-dimensional high velocity impact problems are described.

Extend MANPADS M&S Capabilities to Include Energetic Materials, Fragmentation Effects, and Wing Flutter Response

DTIC Science & Technology

2005-12-31

MANPADS missile is modeled using LSDYNA . It has 187600 nodes, 52802 shell elements with 13 shell materials, 112200 solid elements with 1804 solid...model capability that includes impact, detonation, penetration, and wing flutter response. This work extends an existing body on body missile model...the missile as well as the expansion of the surrounding fluids was modeled in the Eulerian domain. The Jones-Wilkins-Lee (JWL) equation of state was

Nitrogen, phosphorus, and cation use efficiency in stands of regenerating tropical dry forest.

PubMed

Waring, Bonnie G; Becknell, Justin M; Powers, Jennifer S

2015-07-01

Plants on infertile soils exhibit physiological and morphological traits that support conservative internal nutrient cycling. However, potential trade-offs among use efficiencies for N, P, and cations are not well explored in species-rich habitats where multiple elements may limit plant production. We examined uptake efficiency and use efficiency of N, P, K, Ca, Mg, Al, and Na in plots of regenerating tropical dry forests spanning a gradient of soil fertility. Our aim was to determine whether plant responses to multiple elements are correlated, or whether there are trade-offs among exploitation strategies across stands varying in community composition, soil quality, and successional stage. For all elements, both uptake efficiency and use efficiency decreased as availability of the corresponding element increased. Plant responses to N, Na, and Al were uncoupled from uptake and use efficiencies for P and essential base cations, which were tightly correlated. N and P use efficiencies were associated with shifts in plant species composition along the soil fertility gradient, and there was also a trend towards increasing N use efficiency with stand age. N uptake efficiency was positively correlated with the abundance of tree species that associate with ectomycorrhizal fungi. Taken together, our results suggest that successional processes and local species composition interact to regulate plant responses to availability of multiple resources. Successional tropical dry forests appear to employ different strategies to maximize response to N vs. P and K.

Plasmids encoding PKI(1-31), a specific inhibitor of cAMP-stimulated gene expression, inhibit the basal transcriptional activity of some but not all cAMP-regulated DNA response elements in JEG-3 cells.

PubMed

Grove, J R; Deutsch, P J; Price, D J; Habener, J F; Avruch, J

1989-11-25

Plasmids that encode a bioactive amino-terminal fragment of the heat-stable inhibitor of the cAMP-dependent protein kinase, PKI(1-31), were employed to characterize the role of this protein kinase in the control of transcriptional activity mediated by three DNA regulatory elements in the JEG-3 human placental cell line. The 5'-flanking sequence of the human collagenase gene contains the heptameric sequence, 5'-TGAGTCA-3', previously identified as a "phorbol ester" response element. Reporter genes containing either the intact 1.2-kilobase 5'-flanking sequence from the human collagenase gene or just the 7-base pair (bp) response element, when coupled to an enhancerless promoter, each exhibit both cAMP and phorbol ester-stimulated expression in JEG-3 cells. Cotransfection of either construct with plasmids encoding PKI(1-31) inhibits cAMP-stimulated but not basal- or phorbol ester-stimulated expression. Pretreatment of cells with phorbol ester for 1 or 2 days abrogates completely the response to rechallenge with phorbol ester but does not alter the basal expression of either construct; cAMP-stimulated expression, while modestly inhibited, remains vigorous. The 5'-flanking sequence of the human chorionic gonadotropin-alpha subunit (HCG alpha) gene has two copies of the sequence, 5'-TGACGTCA-3', contained in directly adjacent identical 18-bp segments, previously identified as a cAMP-response element. Reporter genes containing either the intact 1.5 kilobase of 5'-flanking sequence from the HCG alpha gene, or just the 36-bp tandem repeat cAMP response element, when coupled to an enhancerless promoter, both exhibit a vigorous cAMP stimulation of expression but no response to phorbol ester in JEG-3 cells. Cotransfection with plasmids encoding PKI(1-31) inhibits both basal and cAMP-stimulated expression in a parallel fashion. The 5'-flanking sequence of the human enkephalin gene mediates cAMP-stimulated expression of reporter genes in both JEG-3 and CV-1 cells. Plasmids encoding PKI(1-31) inhibit the expression that is stimulated by the addition of cAMP analogs in both cell lines; basal expression, however, is inhibited by PKI(1-31) only in the JEG-3 cell line and not in the CV-1 cells. These observations indicate that, in JEG-3 cells, PKI(1-31) is a specific inhibitor of kinase A-mediated gene transcription, but it does not modify kinase C-directed transcription.(ABSTRACT TRUNCATED AT 400 WORDS)

Driver Vision Based Perception-Response Time Prediction and Assistance Model on Mountain Highway Curve.

PubMed

Li, Yi; Chen, Yuren

2016-12-30

To make driving assistance system more humanized, this study focused on the prediction and assistance of drivers' perception-response time on mountain highway curves. Field tests were conducted to collect real-time driving data and driver vision information. A driver-vision lane model quantified curve elements in drivers' vision. A multinomial log-linear model was established to predict perception-response time with traffic/road environment information, driver-vision lane model, and mechanical status (last second). A corresponding assistance model showed a positive impact on drivers' perception-response times on mountain highway curves. Model results revealed that the driver-vision lane model and visual elements did have important influence on drivers' perception-response time. Compared with roadside passive road safety infrastructure, proper visual geometry design, timely visual guidance, and visual information integrality of a curve are significant factors for drivers' perception-response time.

Modules and methods for all photonic computing

DOEpatents

Schultz, David R.; Ma, Chao Hung

2001-01-01

A method for all photonic computing, comprising the steps of: encoding a first optical/electro-optical element with a two dimensional mathematical function representing input data; illuminating the first optical/electro-optical element with a collimated beam of light; illuminating a second optical/electro-optical element with light from the first optical/electro-optical element, the second optical/electro-optical element having a characteristic response corresponding to an iterative algorithm useful for solving a partial differential equation; iteratively recirculating the signal through the second optical/electro-optical element with light from the second optical/electro-optical element for a predetermined number of iterations; and, after the predetermined number of iterations, optically and/or electro-optically collecting output data representing an iterative optical solution from the second optical/electro-optical element.

A comparative study on dynamic stiffness in typical finite element model and multi-body model of C6-C7 cervical spine segment.

PubMed

Wang, Yawei; Wang, Lizhen; Du, Chengfei; Mo, Zhongjun; Fan, Yubo

2016-06-01

In contrast to numerous researches on static or quasi-static stiffness of cervical spine segments, very few investigations on their dynamic stiffness were published. Currently, scale factors and estimated coefficients were usually used in multi-body models for including viscoelastic properties and damping effects, meanwhile viscoelastic properties of some tissues were unavailable for establishing finite element models. Because dynamic stiffness of cervical spine segments in these models were difficult to validate because of lacking in experimental data, we tried to gain some insights on current modeling methods through studying dynamic stiffness differences between these models. A finite element model and a multi-body model of C6-C7 segment were developed through using available material data and typical modeling technologies. These two models were validated with quasi-static response data of the C6-C7 cervical spine segment. Dynamic stiffness differences were investigated through controlling motions of C6 vertebrae at different rates and then comparing their reaction forces or moments. Validation results showed that both the finite element model and the multi-body model could generate reasonable responses under quasi-static loads, but the finite element segment model exhibited more nonlinear characters. Dynamic response investigations indicated that dynamic stiffness of this finite element model might be underestimated because of the absence of dynamic stiffen effect and damping effects of annulus fibrous, while representation of these effects also need to be improved in current multi-body model. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

In vitro element release and biological aspects of base–metal alloys for metal-ceramic applications

PubMed Central

Holm, Charlotta; Morisbak, Else; Kalfoss, Torill; Dahl, Jon E.

2015-01-01

Abstract Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt–chromium alloys and other base–metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt–chromium alloys, three nickel–chromium alloys, two cobalt–chromium–iron alloys, one palladium–silver alloy, one high-noble gold alloy, titanium grade II and one type III copper–aluminium alloy. Pure copper served as positive control. The specimens were prepared according to the ISO standards for biological and corrosion testing. Passive leaching of elements was measured by using Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) after incubation in cell culture media, MEM, for 3 days. Corrosion testing was carried out in 0.9% sodium chloride (NaCl) and 1% lactic acid for 7 days, and the element release was measured by Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). The biological response from the extract solutions was measured though MTT cytotoxicity testing and the Hen's egg test-chorio-allantoic membrane (HET-CAM) technique for irritationt. Results: The corrosion test showed similar element release from base-metal alloys compared to noble alloys such as gold. Apart from the high-copper alloy, all alloys expressed low element release in the immersion test, no cytotoxic effect in the MTT test, and were rated non-irritant in the HET-CAM test. Conclusions: Minimal biological response was observed for all the alloys tested, with the exception of the high-copper alloy. PMID:28642904

A mid-twentieth century reduction in tropical upwelling inferred from coralline trace element proxies

NASA Astrophysics Data System (ADS)

Reuer, Matthew K.; Boyle, Edward A.; Cole, Julia E.

2003-05-01

The Cariaco Basin is an important archive of past climate variability given its response to inter- and extratropical climate forcing and the accumulation of annually laminated sediments within an anoxic water column. This study presents high-resolution surface coral trace element records ( Montastrea annularis and Siderastrea siderea) from Isla Tortuga, Venezuela, located within the upwelling center of this region. A two-fold reduction in Cd/Ca ratios (3.5-1.7 nmol/mol) is observed from 1946 to 1952 with no concurrent shift in Ba/Ca ratios. This reduction agrees with the hydrographic distribution of dissolved cadmium and barium and their expected response to upwelling. Significant anthropogenic variability is also observed from Pb/Ca analysis, observing three lead maxima since 1920. Kinetic control of trace element ratios is inferred from an interspecies comparison of Cd/Ca and Ba/Ca ratios (consistent with the Sr/Ca kinetic artifact), but these artifacts are smaller than the environmental signal and do not explain the Cd/Ca transition. The trace element records agree with historical climate data and differ from sedimentary faunal abundance records, suggesting a linear response to North Atlantic extratropical forcing cannot account for the observed historical variability in this region.

Defective distal regulatory element at the 5' upstream of rat prolactin gene of steroid-nonresponsive GH-subclone.

PubMed

Kumar, V; Wong, D T; Pasion, S G; Biswas, D K

1987-12-08

The prolactin-nonproducing (PRL-) GH cell strains (rat pituitary tumor cells in culture). GH12C1 and F1BGH12C1, do not respond to steroid hormones estradiol or hydrocortisone (HC). However, the stimulatory effect of estradiol and the inhibitory effect of hydrocortisone on prolactin synthesis can be demonstrated in the prolactin-producing GH cell strain, GH4C1. In this investigation we have examined the 5' end flanking region of rat prolactin (rat PRL) gene of steroid-responsive, GH4C1 cells to identify the positive and negative regulatory elements and to verify the status of these elements in steroid-nonresponsive F1BGH12C1 cells. Results presented in this report demonstrate that the basel level expression of the co-transferred Neo gene (neomycin phosphoribosyl transferase) is modulated by the distal upstream regulatory elements of rat PRL gene in response to steroid hormones. The expression of adjacent Neo gene is inhibited by dexamethasone and is stimulated by estradiol in transfectants carrying distal regulatory elements (SRE) of steroid-responsive cells. These responses are not observed in transfectants with the rat PRL upstream sequences derived from steroid-nonresponsive cells. The basal level expression of the host cell alpha-2 tubulin gene is not affected by dexamethasone. We report here the identification of the distal steroid regulatory element (SRE) located between 3.8 and 7.8 kb upstream of the transcription initiation site of rat PRL gene. Both the positive and the negative effects of steroid hormones can be identified within this upstream sequence. This distal SRE appears to be nonfunctional in steroid-nonresponsive cells. Though the proximal SRE is functional, the defect in the distal SRE makes the GH substrain nonresponsive to steroid hormones. These results suggest that both the proximal and the distal SREs are essential for the mediation of action of steroid hormones in GH cells.

Genome-wide identification of galactinol synthase (GolS) genes in Solanum lycopersicum and Brachypodium distachyon.

PubMed

Filiz, Ertugrul; Ozyigit, Ibrahim Ilker; Vatansever, Recep

2015-10-01

GolS genes stand as potential candidate genes for molecular breeding and/or engineering programs in order for improving abiotic stress tolerance in plant species. In this study, a total of six galactinol synthase (GolS) genes/proteins were retrieved for Solanum lycopersicum and Brachypodium distachyon. GolS protein sequences were identified to include glyco_transf_8 (PF01501) domain structure, and to have a close molecular weight (36.40-39.59kDa) and amino acid length (318-347 aa) with a slightly acidic pI (5.35-6.40). The sub-cellular location was mainly predicted as cytoplasmic. S. lycopersicum genes located on chr 1 and 2, and included one segmental duplication while genes of B. distachyon were only on chr 1 with one tandem duplication. GolS sequences were found to have well conserved motif structures. Cis-acting analysis was performed for three abiotic stress responsive elements, including ABA responsive element (ABRE), dehydration and cold responsive elements (DRE/CRT) and low-temperature responsive element (LTRE). ABRE elements were found in all GolS genes, except for SlGolS4; DRE/CRT was not detected in any GolS genes and LTRE element found in SlGolS1 and BdGolS1 genes. AU analysis in UTR and ORF regions indicated that SlGolS and BdGolS mRNAs may have a short half-life. SlGolS3 and SlGolS4 genes may generate more stable transcripts since they included AATTAAA motif for polyadenylation signal POLASIG2. Seconder structures of SlGolS proteins were well conserved than that of BdGolS. Some structural divergences were detected in 3D structures and predicted binding sites exhibited various patterns in GolS proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Joint Enabling Capabilities Command

Science.gov Websites

Executive Director Chief of Staff Joint Planning Support Element Joint Communications Support Element mission Joint Enabling Capabilities Command provides decisive joint communications, planning and public and responsive support for joint communications, planning and public affairs. Priorities * Deliver

Characterizing the stress/defense transcriptome of Arabidopsis

PubMed Central

Mahalingam, Ramamurthy; Gomez-Buitrago, AnaMaria; Eckardt, Nancy; Shah, Nigam; Guevara-Garcia, Angel; Day, Philip; Raina, Ramesh; Fedoroff, Nina V

2003-01-01

Background To understand the gene networks that underlie plant stress and defense responses, it is necessary to identify and characterize the genes that respond both initially and as the physiological response to the stress or pathogen develops. We used PCR-based suppression subtractive hybridization to identify Arabidopsis genes that are differentially expressed in response to ozone, bacterial and oomycete pathogens and the signaling molecules salicylic acid (SA) and jasmonic acid. Results We identified a total of 1,058 differentially expressed genes from eight stress cDNA libraries. Digital northern analysis revealed that 55% of the stress-inducible genes are rarely transcribed in unstressed plants and 17% of them were not previously represented in Arabidopsis expressed sequence tag databases. More than two-thirds of the genes in the stress cDNA collection have not been identified in previous studies as stress/defense response genes. Several stress-responsive cis-elements showed a statistically significant over-representation in the promoters of the genes in the stress cDNA collection. These include W- and G-boxes, the SA-inducible element, the abscisic acid response element and the TGA motif. Conclusions The stress cDNA collection comprises a broad repertoire of stress-responsive genes encoding proteins that are involved in both the initial and subsequent stages of the physiological response to abiotic stress and pathogens. This set of stress-, pathogen- and hormone-modulated genes is an important resource for understanding the genetic interactions underlying stress signaling and responses and may contribute to the characterization of the stress transcriptome through the construction of standardized specialized arrays. PMID:12620105

30 CFR 254.3 - May I cover more than one facility in my response plan?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL-SPILL RESPONSE REQUIREMENTS FOR FACILITIES LOCATED SEAWARD OF THE... Plans must address all the elements required for a response plan in Subpart B, Oil Spill Response Plans for Outer Continental Shelf Facilities, or Subpart D, Oil Spill Response Requirements for Facilities...

30 CFR 254.3 - May I cover more than one facility in my response plan?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL-SPILL RESPONSE REQUIREMENTS FOR FACILITIES LOCATED SEAWARD OF THE... Plans must address all the elements required for a response plan in Subpart B, Oil Spill Response Plans for Outer Continental Shelf Facilities, or Subpart D, Oil Spill Response Requirements for Facilities...

30 CFR 254.3 - May I cover more than one facility in my response plan?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL-SPILL RESPONSE REQUIREMENTS FOR FACILITIES LOCATED SEAWARD OF THE... Plans must address all the elements required for a response plan in Subpart B, Oil Spill Response Plans for Outer Continental Shelf Facilities, or Subpart D, Oil Spill Response Requirements for Facilities...

ACTIVATION OF DIOXIN RESPONSE ELEMENT (DRE)-ASSOCIATED GENES BY BENZO(A)PYRENE 3,6-QUINONE AND BENZO(A)PYRENE 1,6-QUINONE IN MCF-10A HUMAN MAMMARY EPITHELIAL CELLS

PubMed Central

Burchiel, Scott W.; Thompson, Todd A.; Lauer, Fredine T.; Oprea, Tudor I.

2007-01-01

Benzo(a)pyrene (BaP) is a known human carcinogen and a suspected breast cancer complete carcinogen. BaP is metabolized by several metabolic pathways, some having bioactivation and others detoxification properties. BaP-quinones (BPQs) are formed via cytochrome P450 and peroxidase dependent pathways. Previous studies by our laboratory have shown that BPQs have significant growth promoting and anti-apoptotic activities in human MCF-10A mammary epithelial cells examined in vitro. Previous results suggest that BPQs act via redox-cycling and oxidative stress. However, because two specific BPQs (1,6-BPQ and 3,6-BPQ) differed in their ability to produce reactive oxygen species (ROS) and yet both had strong proliferative and EGF receptor activating activity, we utilized mRNA expression arrays and qRT-PCR to determine potential pathways and mechanisms of gene activation. The results of the present studies demonstrated that 1,6-BPQ and 3,6-BPQ activate dioxin response elements (DRE, also known as xenobiotic response elements, XRE) and anti-oxidant response elements (ARE, also known and electrophile response elements, EpRE). 3,6-BPQ had greater DRE activity than 1,6-BPQ, whereas the opposite was true for the activation of ARE. Both 3,6-BPQ and 1,6-BPQ induced oxidative stress associated genes (HMOX1, GCLC, GCLM, and SLC7A11), phase 2 enzyme genes (NQO1, NQO2, ALDH3A1) PAH metabolizing genes (CYP1B1, EPHX1, AKR1C1), and certain EGF receptor associated genes (EGFR, IER3, ING1, SQSTM1 and TRIM16). The results of these studies demonstrate that BPQs activate numerous pathways in human mammary epithelial cells associated with increased cell growth and survival that may play important roles in tumor promotion. PMID:17466351

The pregnane X receptor regulates gene expression in a ligand- and promoter-selective fashion.

PubMed

Masuyama, Hisashi; Suwaki, Naoko; Tateishi, Yoko; Nakatsukasa, Hideki; Segawa, Tomonori; Hiramatsu, Yuji

2005-05-01

Recent studies have revealed that pregnane X receptor (PXR) can function as a master regulator to control the expression of phase I and phase II drug-metabolizing enzymes, as well as members of the drug transporter family, including multiple drug resistance (MDR) 1, which has a major role in multidrug resistance. Previously, we have demonstrated that steroid/xenobiotics metabolism by tumor tissue through the PXR-cytochrome P-450 3A (CYP3A) pathway might play an important role in endometrial cancer. In this study, we examined which endocrine-disrupting chemicals (EDCs) and anticancer agents might be ligands for PXR and whether these chemicals enhanced PXR-mediated transcription through two different PXR-responsive elements (PXREs), CYP3A4 and MDR1, in endometrial cancer cell lines. Some steroids/EDCs strongly activated PXR-mediated transcription through the CYP3A4-responsive element compared with the MDR1-responsive element, whereas these steroids/EDCs also enhanced the CYP3A4 expression compared with the MDR1 expression. In contrast, the anticancer agents, cisplatin and paclitaxel, strongly activated PXR-mediated transcription through the MDR1-responsive element compared with the CYP3A4-responsive element, whereas these drugs also enhanced the MDR1 expression compared with the CYP3A4 expression. We also analyzed how these ligands regulated PXR-mediated transcription through two different PXREs. In the presence of PXR ligands, there was no difference in the DNA binding affinity of the PXR/retinoid X receptor heterodimer to each PXRE, but there were different interactions of the coactivator to each PXR/PXRE complex. These data suggested that PXR ligands enhanced PXR-mediated transcription in a ligand- and promoter-dependent fashion, which in turn differentially regulated the expression of individual PXR targets, especially CYP3A4 and MDR1.

Revisiting the Relationship between Transposable Elements and the Eukaryotic Stress Response.

PubMed

Horváth, Vivien; Merenciano, Miriam; González, Josefa

2017-11-01

A relationship between transposable elements (TEs) and the eukaryotic stress response was suggested in the first publications describing TEs. Since then, it has often been assumed that TEs are activated by stress, and that this activation is often beneficial for the organism. In recent years, the availability of new high-throughput experimental techniques has allowed further interrogation of the relationship between TEs and stress. By reviewing the recent literature, we conclude that although there is evidence for a beneficial effect of TE activation under stress conditions, the relationship between TEs and the eukaryotic stress response is quite complex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantifying uncertainties in the structural response of SSME blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.

1987-01-01

To quantify the uncertainties associated with the geometry and material properties of a Space Shuttle Main Engine (SSME) turbopump blade, a computer code known as STAEBL was used. A finite element model of the blade used 80 triangular shell elements with 55 nodes and five degrees of freedom per node. The whole study was simulated on the computer and no real experiments were conducted. The structural response has been evaluated in terms of three variables which are natural frequencies, root (maximum) stress, and blade tip displacements. The results of the study indicate that only the geometric uncertainties have significant effects on the response. Uncertainties in material properties have insignificant effects.

Elemental Markers in Elasmobranchs: Effects of Environmental History and Growth on Vertebral Chemistry

PubMed Central

Smith, Wade D.; Miller, Jessica A.; Heppell, Selina S.

2013-01-01

Differences in the chemical composition of calcified skeletal structures (e.g. shells, otoliths) have proven useful for reconstructing the environmental history of many marine species. However, the extent to which ambient environmental conditions can be inferred from the elemental signatures within the vertebrae of elasmobranchs (sharks, skates, rays) has not been evaluated. To assess the relationship between water and vertebral elemental composition, we conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, we examined the effects of temperature (16°, 18°, 24°C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca). Second, we tested the relationship between water and subsequent vertebral elemental composition by manipulating dissolved barium concentrations (1x, 3x, 6x). We also evaluated the influence of natural variation in growth rate on elemental incorporation for both experiments. Finally, we examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. Temperature had strong, negative effects on the uptake of magnesium (DMg) and barium (DBa) and positively influenced manganese (DMn) incorporation. Temperature-dependent responses were not observed for lithium and strontium. Vertebral Ba/Ca was positively correlated with ambient Ba/Ca. Partition coefficients (DBa) revealed increased discrimination of barium in response to increased dissolved barium concentrations. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements except Zn. Relationships between somatic growth rate and DZn were, however, inconsistent and inconclusive. Variation in the vertebral elemental signatures of U. halleri reliably distinguished individual rays from each treatment based on temperature (85%) and Ba exposure (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. Vertebral elemental analysis is a promising tool for the study of elasmobranch population structure, movement, and habitat use. PMID:24098320

Elemental markers in elasmobranchs: effects of environmental history and growth on vertebral chemistry.

PubMed

Smith, Wade D; Miller, Jessica A; Heppell, Selina S

2013-01-01

Differences in the chemical composition of calcified skeletal structures (e.g. shells, otoliths) have proven useful for reconstructing the environmental history of many marine species. However, the extent to which ambient environmental conditions can be inferred from the elemental signatures within the vertebrae of elasmobranchs (sharks, skates, rays) has not been evaluated. To assess the relationship between water and vertebral elemental composition, we conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, we examined the effects of temperature (16°, 18°, 24°C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca). Second, we tested the relationship between water and subsequent vertebral elemental composition by manipulating dissolved barium concentrations (1x, 3x, 6x). We also evaluated the influence of natural variation in growth rate on elemental incorporation for both experiments. Finally, we examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. Temperature had strong, negative effects on the uptake of magnesium (DMg) and barium (DBa) and positively influenced manganese (DMn) incorporation. Temperature-dependent responses were not observed for lithium and strontium. Vertebral Ba/Ca was positively correlated with ambient Ba/Ca. Partition coefficients (DBa) revealed increased discrimination of barium in response to increased dissolved barium concentrations. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements except Zn. Relationships between somatic growth rate and DZn were, however, inconsistent and inconclusive. Variation in the vertebral elemental signatures of U. halleri reliably distinguished individual rays from each treatment based on temperature (85%) and Ba exposure (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. Vertebral elemental analysis is a promising tool for the study of elasmobranch population structure, movement, and habitat use.

Involvement of activator protein 1 complexes in the epithelium-specific activation of the laminin gamma2-chain gene promoter by hepatocyte growth factor (scatter factor).

PubMed Central

Olsen, J; Lefebvre, O; Fritsch, C; Troelsen, J T; Orian-Rousseau, V; Kedinger, M; Simon-Assmann, P

2000-01-01

Laminin-5 is a trimer of laminin alpha3, beta3 and gamma2 chains that is found in the intestinal basement membrane. Deposition of the laminin gamma2 chain at the basement membrane is of great interest because it undergoes a developmental shift in its cellular expression. Here we study the regulatory elements that control basal and cytokine-activated transcriptional expression of the LAMC2 gene, which encodes the laminin gamma2 chain. By using transient transfection experiments we demonstrated the presence of constitutive and cytokine-responsive cis-elements. Comparison of the transcriptional activity of the LAMC2 promoter in the epithelial HT29mtx cells with that in small-intestinal fibroblastic cells (C20 cells) led us to conclude that two regions with constitutive epithelium-specific activity are present between positions -1.2 and -0.12 kb. This was further validated by transfections of primary foetal intestinal endoderm and mesenchyme. A 2.5 kb portion of the LAMC2 5' flanking region was equally responsive to PMA and hepatocyte growth factor (HGF), whereas it was less responsive to transforming growth factor beta1. A minimal promoter limited to the initial 120 bp upstream of the transcriptional start site maintained inducibility by PMA and HGF. This short promoter fragment contains two activator protein 1 (AP-1) elements and the 5'-most of these is a composite AP-1/Sp1 element. The 5'AP-1 element is crucial to the HGF-mediated activity of the promoter; analysis of interacting nuclear proteins demonstrated that AP-1 proteins containing JunD mediate the response to HGF. PMID:10749670

The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry

NASA Astrophysics Data System (ADS)

Patra, Nipanjana; Parsons, Aaron R.; DeBoer, David R.; Thyagarajan, Nithyanandan; Ewall-Wice, Aaron; Hsyu, Gilbert; Leung, Tsz Kuk; Day, Cherie K.; de Lera Acedo, Eloy; Aguirre, James E.; Alexander, Paul; Ali, Zaki S.; Beardsley, Adam P.; Bowman, Judd D.; Bradley, Richard F.; Carilli, Chris L.; Cheng, Carina; Dillon, Joshua S.; Fadana, Gcobisa; Fagnoni, Nicolas; Fritz, Randall; Furlanetto, Steve R.; Glendenning, Brian; Greig, Bradley; Grobbelaar, Jasper; Hazelton, Bryna J.; Jacobs, Daniel C.; Julius, Austin; Kariseb, MacCalvin; Kohn, Saul A.; Lebedeva, Anna; Lekalake, Telalo; Liu, Adrian; Loots, Anita; MacMahon, David; Malan, Lourence; Malgas, Cresshim; Maree, Matthys; Martinot, Zachary; Mathison, Nathan; Matsetela, Eunice; Mesinger, Andrei; Morales, Miguel F.; Neben, Abraham R.; Pieterse, Samantha; Pober, Jonathan C.; Razavi-Ghods, Nima; Ringuette, Jon; Robnett, James; Rosie, Kathryn; Sell, Raddwine; Smith, Craig; Syce, Angelo; Tegmark, Max; Williams, Peter K. G.; Zheng, Haoxuan

2018-04-01

Spectral structures due to the instrument response is the current limiting factor for the experiments attempting to detect the redshifted 21 cm signal from the Epoch of Reionization (EoR). Recent advances in the delay spectrum methodology for measuring the redshifted 21 cm EoR power spectrum brought new attention to the impact of an antenna's frequency response on the viability of making this challenging measurement. The delay spectrum methodology provides a somewhat straightforward relationship between the time-domain response of an instrument that can be directly measured and the power spectrum modes accessible to a 21 cm EoR experiment. In this paper, we derive the explicit relationship between antenna reflection coefficient ( S 11) measurements made by a Vector Network Analyzer (VNA) and the extent of additional foreground contaminations in delay space. In the light of this mathematical framework, we examine the chromaticity of a prototype antenna element that will constitute the Hydrogen Epoch of Reionization Array (HERA) between 100 and 200 MHz. These reflectometry measurements exhibit additional structures relative to electromagnetic simulations, but we find that even without any further design improvement, such an antenna element will support measuring spatial k modes with line-of-sight components of k ∥ > 0.2 h Mpc- 1. We also find that when combined with the powerful inverse covariance weighting method used in optimal quadratic estimation of redshifted 21 cm power spectra the HERA prototype elements can successfully measure the power spectrum at spatial modes as low as k ∥ > 0.1 h Mpc- 1. This work represents a major step toward understanding the HERA antenna element and highlights a straightforward method for characterizing instrument response for future experiments designed to detect the 21 cm EoR power spectrum.

In silico analysis of high affinity potassium transporter (HKT) isoforms in different plants

PubMed Central

2014-01-01

Background High affinity potassium transporters (HKTs) are located in the plasma membrane of the vessels and have significant influence on salt tolerance in some plants. They exclude Na+ from the parenchyma cells to reduce Na+ concentration. Despite many studies, the underlying regulatory mechanisms and the exact functions of HKTs within different genomic backgrounds are relatively unknown. In this study, various bioinformatics techniques, including promoter analysis, identification of HKT-surrounding genes, and construction of gene networks, were applied to investigate the HKT regulatory mechanism. Results Promoter analysis showed that rice HKTs carry ABA response elements. Additionally, jasmonic acid response elements were detected on promoter region of TmHKT1;5. In silico synteny highlighted several unknown and new loci near rice, Arabidopsis thaliana and Physcomitrella patent HKTs, which may play a significant role in salt stress tolerance in concert with HKTs. Gene network prediction unravelled that crosstalk between jasmonate and ethylene reduces AtHKT1;1 expression. Furthermore, antiporter and transferase proteins were found in AtHKT1;1 gene network. Interestingly, regulatory elements on the promoter region of HKT in wild genotype (TmHKT1;5) were more frequent and variable than the ones in cultivated wheat (TaHKT1;5) which provides the possibility of rapid response and better understanding of environmental conditions for wild genotype. Conclusion Detecting ABA and jasmonic acid response elements on promoter regions of HKTs provide valuable clues on underlying regulatory mechanisms of HKTs. In silico synteny and pathway discovery indicated several candidates which act in concert with HKTs in stress condition. We highlighted different arrangement of regulatory elements on promoter region of wild wheat (TmHKT1;5) compared to bread wheat (TaHKT1;5) in this study. PMID:25279141

Quantitative statistical analysis of cis-regulatory sequences in ABA/VP1- and CBF/DREB1-regulated genes of Arabidopsis.

PubMed

Suzuki, Masaharu; Ketterling, Matthew G; McCarty, Donald R

2005-09-01

We have developed a simple quantitative computational approach for objective analysis of cis-regulatory sequences in promoters of coregulated genes. The program, designated MotifFinder, identifies oligo sequences that are overrepresented in promoters of coregulated genes. We used this approach to analyze promoter sequences of Viviparous1 (VP1)/abscisic acid (ABA)-regulated genes and cold-regulated genes, respectively, of Arabidopsis (Arabidopsis thaliana). We detected significantly enriched sequences in up-regulated genes but not in down-regulated genes. This result suggests that gene activation but not repression is mediated by specific and common sequence elements in promoters. The enriched motifs include several known cis-regulatory sequences as well as previously unidentified motifs. With respect to known cis-elements, we dissected the flanking nucleotides of the core sequences of Sph element, ABA response elements (ABREs), and the C repeat/dehydration-responsive element. This analysis identified the motif variants that may correlate with qualitative and quantitative differences in gene expression. While both VP1 and cold responses are mediated in part by ABA signaling via ABREs, these responses correlate with unique ABRE variants distinguished by nucleotides flanking the ACGT core. ABRE and Sph motifs are tightly associated uniquely in the coregulated set of genes showing a strict dependence on VP1 and ABA signaling. Finally, analysis of distribution of the enriched sequences revealed a striking concentration of enriched motifs in a proximal 200-base region of VP1/ABA and cold-regulated promoters. Overall, each class of coregulated genes possesses a discrete set of the enriched motifs with unique distributions in their promoters that may account for the specificity of gene regulation.

45 CFR Appendix E to Part 1355 - Data Standards

Code of Federal Regulations, 2013 CFR

2013-10-01

... responses to the element, Sex of the Adoptive Child, is “1” for a male and “2” for a female, but the datum.... Element description 05 Date of most recent periodic, review. 06 Child's date of birth. 07 Child's sex. 08.... Element name 05 Child's date of birth. 06 Child's sex. 07 Child's race. 08 Is the child of Hispanic or...

45 CFR Appendix E to Part 1355 - Data Standards

Code of Federal Regulations, 2014 CFR

2014-10-01

... responses to the element, Sex of the Adoptive Child, is “1” for a male and “2” for a female, but the datum.... Element description 05 Date of most recent periodic, review. 06 Child's date of birth. 07 Child's sex. 08.... Element name 05 Child's date of birth. 06 Child's sex. 07 Child's race. 08 Is the child of Hispanic or...

45 CFR Appendix E to Part 1355 - Data Standards

Code of Federal Regulations, 2012 CFR

2012-10-01

... responses to the element, Sex of the Adoptive Child, is “1” for a male and “2” for a female, but the datum.... Element description 05 Date of most recent periodic, review. 06 Child's date of birth. 07 Child's sex. 08.... Element name 05 Child's date of birth. 06 Child's sex. 07 Child's race. 08 Is the child of Hispanic or...

Reference Models for Multi-Layer Tissue Structures

DTIC Science & Technology

2016-09-01

simulation,  finite   element  analysis 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON USAMRMC...Physiologically realistic, fully specimen-specific, nonlinear reference models. Tasks. Finite element analysis of non-linear mechanics of cadaver...models. Tasks. Finite element analysis of non-linear mechanics of multi-layer tissue regions of human subjects. Deliverables. Partially subject- and

Component mode synthesis and large deflection vibration of complex structures. Volume 3: Multiple-mode nonlinear free and forced vibrations of beams using finite element method

NASA Technical Reports Server (NTRS)

Mei, Chuh; Shen, Mo-How

1987-01-01

Multiple-mode nonlinear forced vibration of a beam was analyzed by the finite element method. Inplane (longitudinal) displacement and inertia (IDI) are considered in the formulation. By combining the finite element method and nonlinear theory, more realistic models of structural response are obtained more easily and faster.

Determination of elemental content off rocks by laser ablation inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Lichte, F.E.

1995-01-01

A new method of analysis for rocks and soils is presented using laser ablation inductively coupled plasma mass spectrometry. It is based on a lithium borate fusion and the free-running mode of a Nd/YAG laser. An Ar/N2 sample gas improves sensitivity 7 ?? for most elements. Sixty-three elements are characterized for the fusion, and 49 elements can be quantified. Internal standards and isotopic spikes ensure accurate results. Limits of detection are 0.01 ??g/g for many trace elements. Accuracy approaches 5% for all elements. A new quality assurance procedure is presented that uses fundamental parameters to test relative response factors for the calibration.

Bistability in mushroom-type metamaterials

NASA Astrophysics Data System (ADS)

Fernandes, David E.; Silveirinha, Mário G.

2017-07-01

Here, we study the electromagnetic response of asymmetric mushroom-type metamaterials loaded with nonlinear elements. It is shown that near a Fano resonance, these structures may have a strong tunable, bistable, and switchable response and enable giant nonlinear effects. By using an effective medium theory and full wave simulations, it is proven that the nonlinear elements may allow the reflection and transmission coefficients to follow hysteresis loops, and to switch the metamaterial between "go" and "no-go" states similar to an ideal electromagnetic switch.

Quantal Response: Nonparametric Modeling

DTIC Science & Technology

2017-01-01

DATES COVERED (From ‐ To) 4. TITLE AND SUBTITLE    5a. CONTRACT NUMBER  5b. GRANT NUMBER  5c. PROGRAM  ELEMENT  NUMBER 6. AUTHOR(S)    5d...creasing function as P(x) = G ( f (x) ) , where G is a monotone function such as the standard logistic, normal, or Cauchy CDF. Finite -dimensional...examples with dimension k = 5 where various colors distinguish the basis elements . Figure 3 shows logistic response estimates for these 3 basis sets

QTL mapping of sulfur tolerance in melon

USDA-ARS?s Scientific Manuscript database

Elemental sulfur is a cheap, effective fungicide with multi-site action, which inhibits the evolution of pathogen resistance. Fungal pathogens cause significant yield losses in melon production. Many melon genotypes, however, suffer leaf necrosis in response to elemental sulfur application preventin...

Non-additive interactions involving two distinct elements mediate sloppy-paired regulation by pair-rule transcription factors

PubMed Central

Prazak, Lisa; Fujioka, Miki; Gergen, J. Peter

2010-01-01

The relatively simple combinatorial rules responsible for establishing the initial metameric expression of sloppy-paired-1 (slp1) in the Drosophila blastoderm embryo make this system an attractive model for investigating the mechanism of regulation by pair rule transcription factors. This investigation of slp1 cis-regulatory architecture identifies two distinct elements, a proximal early stripe element (PESE) and a distal early stripe element (DESE) located from −3.1 kb to −2.5 kb and from −8.1 kb to −7.1 kb upstream of the slp1 promoter, respectively, that mediate this early regulation. The proximal element expresses only even-numbered stripes and mediates repression by Even-skipped (Eve) as well as by the combination of Runt and Fushi-tarazu (Ftz). A 272 basepair sub-element of PESE retains Eve-dependent repression, but is expressed throughout the even-numbered parasegments due to the loss of repression by Runt and Ftz. In contrast, the distal element expresses both odd and even-numbered stripes and also drives inappropriate expression in the anterior half of the odd-numbered parasegments due to an inability to respond to repression by Eve. Importantly, a composite reporter gene containing both early stripe elements recapitulates pair-rule gene-dependent regulation in a manner beyond what is expected from combining their individual patterns. These results indicate interactions involving distinct cis-elements contribute to the proper integration of pair-rule regulatory information. A model fully accounting for these results proposes that metameric slp1 expression is achieved through the Runt-dependent regulation of interactions between these two pair-rule response elements and the slp1 promoter. PMID:20435028

Densely ionizing radiation affects DNA methylation of selective LINE-1 elements

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

Prior, Sara; Miousse, Isabelle R.

Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2′-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promotermore » type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5′-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR. - Highlights: • DNA methylation of LINE-1 elements is dependent on their evolutionary age. • Densely ionizing radiation affects DNA methylation of selective LINE-1 elements. • Radiation-induced reactivation of LINE-1 is DNA methylation-independent. • Histone modifications dictate the transcriptional activity of LINE-1.« less

Response to conflict among wilderness visitors

Treesearch

Ingrid Schneider

2000-01-01

Previous conceptual efforts suggest that response to recreational conflict should be framed within an adapted stresscoping response model. An important element in understanding response to conflict is the context of the experience. A basic underlying component of the wilderness experience is privacy, which indicates wilderness visitors are interested in releasing—...

Abscisic Acid (ABA) Regulation of Arabidopsis SR Protein Gene Expression

PubMed Central

Cruz, Tiago M. D.; Carvalho, Raquel F.; Richardson, Dale N.; Duque, Paula

2014-01-01

Serine/arginine-rich (SR) proteins are major modulators of alternative splicing, a key generator of proteomic diversity and flexible means of regulating gene expression likely to be crucial in plant environmental responses. Indeed, mounting evidence implicates splicing factors in signal transduction of the abscisic acid (ABA) phytohormone, which plays pivotal roles in the response to various abiotic stresses. Using real-time RT-qPCR, we analyzed total steady-state transcript levels of the 18 SR and two SR-like genes from Arabidopsis thaliana in seedlings treated with ABA and in genetic backgrounds with altered expression of the ABA-biosynthesis ABA2 and the ABA-signaling ABI1 and ABI4 genes. We also searched for ABA-responsive cis elements in the upstream regions of the 20 genes. We found that members of the plant-specific SC35-Like (SCL) Arabidopsis SR protein subfamily are distinctively responsive to exogenous ABA, while the expression of seven SR and SR-related genes is affected by alterations in key components of the ABA pathway. Finally, despite pervasiveness of established ABA-responsive promoter elements in Arabidopsis SR and SR-like genes, their expression is likely governed by additional, yet unidentified cis-acting elements. Overall, this study pinpoints SR34, SR34b, SCL30a, SCL28, SCL33, RS40, SR45 and SR45a as promising candidates for involvement in ABA-mediated stress responses. PMID:25268622

Variations in the Composition of Gelling Agents Affect Morphophysiological and Molecular Responses to Deficiencies of Phosphate and Other Nutrients1[C][W][OA

PubMed Central

Jain, Ajay; Poling, Michael D.; Smith, Aaron P.; Nagarajan, Vinay K.; Lahner, Brett; Meagher, Richard B.; Raghothama, Kashchandra G.

2009-01-01

Low inorganic phosphate (Pi) availability triggers an array of spatiotemporal adaptive responses in Arabidopsis (Arabidopsis thaliana). There are several reports on the effects of Pi deprivation on the root system that have been attributed to different growth conditions and/or inherent genetic variability. Here we show that the gelling agents, largely treated as inert components, significantly affect morphophysiological and molecular responses of the seedlings to deficiencies of Pi and other nutrients. Inductively coupled plasma-mass spectroscopy analysis revealed variable levels of elemental contaminants not only in different types of agar but also in different batches of the same agar. Fluctuating levels of phosphorus (P) in different agar types affected the growth of the seedlings under Pi-deprivation condition. Since P interacts with other elements such as iron, potassium, and sulfur, contaminating effects of these elements in different agars were also evident in the Pi-deficiency-induced morphological and molecular responses. P by itself acted as a contaminant when studying the responses of Arabidopsis to micronutrient (iron and zinc) deficiencies. Together, these results highlighted the likelihood of erroneous interpretations that could be easily drawn from nutrition studies when different agars have been used. As an alternative, we demonstrate the efficacy of a sterile and contamination-free hydroponic system for dissecting morphophysiological and molecular responses of Arabidopsis to different nutrient deficiencies. PMID:19386810

A cavity radiometer for Earth albedo measurement, phase 1

NASA Technical Reports Server (NTRS)

1987-01-01

Radiometric measurements of the directional albedo of the Earth requires a detector with a flat response from 0.2 to 50 microns, a response time of about 2 seconds, a sensitivity of the order of 0.02 mw/sq cm, and a measurement uncertainty of less than 5 percent. Absolute cavity radiometers easily meet the spectral response and accuracy requirements for Earth albedo measurements, but the radiometers available today lack the necessary sensitivity and response time. The specific innovations addressed were the development of a very low thermal mass cavity and printed/deposited thermocouple sensing elements which were incorporated into the radiometer design to produce a sensitive, fast response, absolute radiometer. The cavity is applicable to the measurement of the reflected and radiated fluxes from the Earth surface and lower atmosphere from low Earth orbit satellites. The effort consisted of requirements and thermal analysis; design, construction, and test of prototype elements of the black cavity and sensor elements to show proof-of-concept. The results obtained indicate that a black body cavity sensor that has inherently a flat response from 0.2 to 50 microns can be produced which has a sensitivity of at least 0.02 mw/sq cm per micro volt ouput and with a time constant of less than two seconds. Additional work is required to develop the required thermopile.

A spline-based approach for computing spatial impulse responses.

PubMed

Ellis, Michael A; Guenther, Drake; Walker, William F

2007-05-01

Computer simulations are an essential tool for the design of phased-array ultrasonic imaging systems. FIELD II, which determines the two-way temporal response of a transducer at a point in space, is the current de facto standard for ultrasound simulation tools. However, the need often arises to obtain two-way spatial responses at a single point in time, a set of dimensions for which FIELD II is not well optimized. This paper describes an analytical approach for computing the two-way, far-field, spatial impulse response from rectangular transducer elements under arbitrary excitation. The described approach determines the response as the sum of polynomial functions, making computational implementation quite straightforward. The proposed algorithm, named DELFI, was implemented as a C routine under Matlab and results were compared to those obtained under similar conditions from the well-established FIELD II program. Under the specific conditions tested here, the proposed algorithm was approximately 142 times faster than FIELD II for computing spatial sensitivity functions with similar amounts of error. For temporal sensitivity functions with similar amounts of error, the proposed algorithm was about 1.7 times slower than FIELD II using rectangular elements and 19.2 times faster than FIELD II using triangular elements. DELFI is shown to be an attractive complement to FIELD II, especially when spatial responses are needed at a specific point in time.

Deconfounding the effects of local element spatial heterogeneity and sparsity on processing dominance.

PubMed

Montoro, Pedro R; Luna, Dolores

2009-10-01

Previous studies on the processing of hierarchical patterns (Luna & Montoro, 2008) have shown that altering the spatial relationships between the local elements affected processing dominance by decreasing global advantage. In the present article, the authors examine whether heterogeneity or a sparse distribution of the local elements was the responsible factor for this effect. In Experiments 1 and 2, the distance between the local elements was increased in a similar way, but between-element distance was homogeneous in Experiment 1 and heterogeneous in Experiment 2. In Experiment 3, local elements' size was varied by presenting global patterns composed of similar large or small local elements and of different large and small sizes. The results of the present research showed that, instead of element sparsity, spatial heterogeneity that could change the appearance of the global form as well as the salience of the local elements was the main determiner of impairing global processing.

Removing but not adding elements of a context affects generalization of instrumental responses.

PubMed

Bernal-Gamboa, Rodolfo; Nieto, Javier; Uengoer, Metin

2018-01-05

Three experiments with rats investigated whether adding or removing elements of a context affects generalization of instrumental behavior. Each of the experiments used a free operant procedure. In Experiments 1 and 2, rats were trained to press a lever for food in a distinctive context. Then, transfer of lever pressing was tested in a context created either by adding an element to the context of initial acquisition or by removing one of the acquisition context's elements. In Experiment 3, a similar generalization test was conducted after rats received acquisition and extinction within the same context. For Experiments 1 and 2, we observed that removing elements from the acquisition context disrupted acquisition performance, whereas the addition of elements to the context did not. Experiment 3 revealed that removing elements from but not adding elements to the original context improved extinction performance. Our results are consistent with an elemental view of context representation.

Endothelial responses of magnesium and other alloying elements in magnesium-based stent materials

PubMed Central

Zhao, Nan; Zhu, Donghui

2016-01-01

Biodegradable tailored magnesium (Mg) alloys are some of the most promising scaffolds for cardiovascular stents. During the course of degradation after implantation, all the alloying elements in the scaffold will be released to the surrounding vascular tissues. However, fundamental questions regarding the toxicity of alloying elements towards vascular cells, the maximum amount of each element that could be used in alloy design, or how each of the alloying elements affects vascular cellular activity and gene expression, are still not fully answered. This work systematically addressed these questions by revealing how application of different alloying elements commonly used in Mg stent materials influences several indices of human endothelial cell health, i.e., viability, proliferations, cytoskeletal reorganizations, migration, and the gene expression profile. The overall cell viability and proliferation showed a decreasing trend with increasing concentrations of the ions, and the half maximal effective concentrations (EC50) for each element were determined. When applied at a low concentration of around 10 mM, Mg had no adverse effects but improved cell proliferation and migration instead. Mg ions also altered endothelial gene expression significantly in a dose dependent manner. Most of the changed genes are related to angiogenesis and the cell adhesion signaling pathways. Findings from this work provide useful information on maximum safe doses of these ions for endothelial cells, endothelial responses towards these metal ions, and some guidance for future Mg stent design. PMID:25363018

Development of a rapidly deployed Department of Energy emergency response element.

PubMed

Tighe, R J; Riland, C A; Hopkins, R C

2000-02-01

The Federal Radiological Emergency Response Plan (FRERP) directs the Department of Energy (DOE) to maintain a viable, timely, and fully documented response option capable of supporting the responsible Lead Federal Agency in the event of a radiological emergency impacting any state or United States territory (e.g., CONUS). In addition, the DOE maintains a response option to support radiological emergencies outside the continental United States (OCONUS). While the OCONUS mission is not governed by the FRERP, this response is operationally similar to that assigned to the DOE by the FRERP The DOE is prepared to alert, activate, and deploy radiological response teams to augment the Radiological Assistance Program and/or local responders. The Radiological Monitoring and Assessment Center (RMAC) is a phased response that integrates with the Federal Radiological Monitoring and Assessment Center (FRMAC) in CONUS environments and represents a stand-alone DOE response for OCONUS environments. The FRMAC/RMAC Phase I was formally "stood up" as an operational element in April 1999. The FRMAC/RMAC Phase II proposed "stand-up" date is midyear 2000.

Multiple elements of the allergic arm of the immune response modulate autoimmune demyelination

PubMed Central

Pedotti, Rosetta; DeVoss, Jason J.; Youssef, Sawsan; Mitchell, Dennis; Wedemeyer, Jochen; Madanat, Rami; Garren, Hideki; Fontoura, Paulo; Tsai, Mindy; Galli, Stephen J.; Sobel, Raymond A.; Steinman, Lawrence

2003-01-01

Analysis of mRNA from multiple sclerosis lesions revealed increased amounts of transcripts for several genes encoding molecules traditionally associated with allergic responses, including prostaglandin D synthase, histamine receptor type 1 (H1R), platelet activating factor receptor, Ig Fc ɛ receptor 1 (FcɛRI), and tryptase. We now demonstrate that, in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), mediated by T helper 1 (Th1) T cells, histamine receptor 1 and 2 (H1R and H2R) are present on inflammatory cells in brain lesions. Th1 cells reactive to myelin proteolipid protein expressed more H1R and less H2R than Th2 cells. Pyrilamine, an H1R antagonist, blocked EAE, and the platelet activating factor receptor antagonist CV6209 reduced the severity of EAE. EAE severity was also decreased in mice with disruption of the genes encoding Ig FcγRIII or both FcγRIII and FcɛRI. Prostaglandin D synthase and tryptase transcripts were elevated in EAE brain. Taken together, these data reveal extensive involvement of elements of the immune response associated with allergy in autoimmune demyelination. The pathogenesis of demyelination must now be viewed as encompassing elements of both Th1 responses and “allergic” responses. PMID:12576552

Force Limiting Vibration Tests Evaluated from both Ground Acoustic Tests and FEM Simulations of a Flight Like Vehicle System Assembly

NASA Technical Reports Server (NTRS)

Smith, Andrew; LaVerde, Bruce; Waldon, James; Hunt, Ron

2014-01-01

Marshall Space Flight Center has conducted a series of ground acoustic tests with the dual goals of informing analytical judgment, and validating analytical methods when estimating vibroacoustic responses of launch vehicle subsystems. The process of repeatedly correlating finite element-simulated responses with test-measured responses has assisted in the development of best practices for modeling and post-processing. In recent work, force transducers were integrated to measure interface forces at the base of avionics box equipment. Other force data was indirectly measured using strain gauges. The combination of these direct and indirect force measurements has been used to support and illustrate the advantages of implementing the Force Limiting approach for equipment qualification tests. The comparison of force response from integrated system level tests to measurements at the same locations during component level vibration tests provides an excellent illustration. A second comparison of the measured response cases from the system level acoustic tests to finite element simulations has also produced some principles for assessing the suitability of Finite Element Models (FEMs) for making vibroacoustics estimates. The results indicate that when FEM models are employed to guide force limiting choices, they should include sufficient detail to represent the apparent mass of the system in the frequency range of interest.

An experimental and analytical investigation on the response of GR/EP composite I-frames

NASA Technical Reports Server (NTRS)

Moas, E., Jr.; Boitnott, R. L.; Griffin, O. H., Jr.

1991-01-01

Six-foot diameter, semicircular graphite/epoxy specimens representative of generic aircraft frames were loaded quasi-statically to determine their load response and failure mechanisms for large deflections that occur in an airplane crash. These frame-skin specimens consisted of a cylindrical skin section cocured with a semicircular I-frame. Various frame laminate stacking sequences and geometries were evaluated by statically loading the specimen until multiple failures occurred. Two analytical methods were compared for modeling the frame-skin specimens: a two-dimensional branched-shell finite element analysis and a one-dimensional, closed-form, curved beam solution derived using an energy method. Excellent correlation was obtained between experimental results and the finite element predictions of the linear response of the frames prior to the initial failure. The beam solution was used for rapid parameter and design studies, and was found to be stiff in comparison with the finite element analysis. The specimens were found to be useful for evaluating composite frame designs.

Identification and functional characterization of BTas transactivator as a DNA-binding protein.

PubMed

Tan, Juan; Hao, Peng; Jia, Rui; Yang, Wei; Liu, Ruichang; Wang, Jinzhong; Xi, Zhen; Geng, Yunqi; Qiao, Wentao

2010-09-30

The genome of bovine foamy virus (BFV) encodes a transcriptional transactivator, namely BTas, that remarkably enhances gene expression by binding to the viral long-terminal repeat promoter (LTR) and internal promoter (IP). In this report, we characterized the functional domains of BFV BTas. BTas contains two major functional domains: the N-terminal DNA-binding domain (residues 1-133) and the C-terminal activation domain (residues 198-249). The complete BTas responsive regions were mapped to the positions -380/-140 of LTR and 9205/9276 of IP. Four BTas responsive elements were identified at the positions -368/-346, -327/-307, -306/-285 and -186/-165 of the BFV LTR, and one element was identified at the position 9243/9264 of the BFV IP. Unlike other foamy viruses, the five BTas responsive elements in BFV shared obvious sequence homology. These data suggest that among the complex retroviruses, BFV appears to have a unique transactivation mechanism. Crown Copyright 2010. Published by Elsevier Inc. All rights reserved.

Application of Dynamic Analysis in Semi-Analytical Finite Element Method.

PubMed

Liu, Pengfei; Xing, Qinyan; Wang, Dawei; Oeser, Markus

2017-08-30

Analyses of dynamic responses are significantly important for the design, maintenance and rehabilitation of asphalt pavement. In order to evaluate the dynamic responses of asphalt pavement under moving loads, a specific computational program, SAFEM, was developed based on a semi-analytical finite element method. This method is three-dimensional and only requires a two-dimensional FE discretization by incorporating Fourier series in the third dimension. In this paper, the algorithm to apply the dynamic analysis to SAFEM was introduced in detail. Asphalt pavement models under moving loads were built in the SAFEM and commercial finite element software ABAQUS to verify the accuracy and efficiency of the SAFEM. The verification shows that the computational accuracy of SAFEM is high enough and its computational time is much shorter than ABAQUS. Moreover, experimental verification was carried out and the prediction derived from SAFEM is consistent with the measurement. Therefore, the SAFEM is feasible to reliably predict the dynamic response of asphalt pavement under moving loads, thus proving beneficial to road administration in assessing the pavement's state.

A Distal ABA Responsive Element in AtNCED3 Promoter Is Required for Positive Feedback Regulation of ABA Biosynthesis in Arabidopsis

PubMed Central

Yang, Yan-Zhuo; Tan, Bao-Cai

2014-01-01

The plant hormone abscisic acid (ABA) plays a crucial role in plant development and responses to abiotic stresses. Recent studies indicate that a positive feedback regulation by ABA exists in ABA biosynthesis in plants under dehydration stress. To understand the molecular basis of this regulation, we analyzed the cis-elements of the AtNCED3 promoter in Arabidopsis. AtNCED3 encodes the first committed and highly regulated dioxygenase in the ABA biosynthetic pathway. Through delineated and mutagenesis analyses in stable-transformed Arabidopsis, we revealed that a distal ABA responsive element (ABRE: GGCACGTG, -2372 to -2364 bp) is required for ABA-induced AtNCED3 expression. By analyzing the AtNCED3 expression in ABRE binding protein ABF3 over-expression transgenic plants and knock-out mutants, we provide evidence that the ABA feedback regulation of AtNCED3 expression is not mediated by ABF3. PMID:24475264

Experiments and numerical simulations of nonlinear vibration responses of an assembly with friction joints - Application on a test structure named "Harmony"

NASA Astrophysics Data System (ADS)

Claeys, M.; Sinou, J.-J.; Lambelin, J.-P.; Todeschini, R.

2016-03-01

In presence of friction, the frequency response function of a metallic assembly is strongly dependent on the excitation level. The local stick-slip behavior at the friction interfaces induces energy dissipation and local stiffness softening. These phenomena are studied both experimentally and numerically on a test structure named "Harmony". Concerning the numerical part, a classical complete methodology from the finite element and friction modeling to the prediction of the nonlinear vibrational response is implemented. The well-known Harmonic Balance Method with a specific condensation process on the nonlinear frictional elements is achieved. Also, vibration experiments are performed to validate not only the finite element model of the test structure named "Harmony" at low excitation levels but also to investigate the nonlinear behavior of the system on several excitation levels. A scanning laser vibrometer is used to measure the nonlinear behavior and the local stick-slip movement near the contacts.

Improving the value of clinical research through the use of Common Data Elements.

PubMed

Sheehan, Jerry; Hirschfeld, Steven; Foster, Erin; Ghitza, Udi; Goetz, Kerry; Karpinski, Joanna; Lang, Lisa; Moser, Richard P; Odenkirchen, Joanne; Reeves, Dianne; Rubinstein, Yaffa; Werner, Ellen; Huerta, Michael

2016-12-01

The use of Common Data Elements can facilitate cross-study comparisons, data aggregation, and meta-analyses; simplify training and operations; improve overall efficiency; promote interoperability between different systems; and improve the quality of data collection. A Common Data Element is a combination of a precisely defined question (variable) paired with a specified set of responses to the question that is common to multiple datasets or used across different studies. Common Data Elements, especially when they conform to accepted standards, are identified by research communities from variable sets currently in use or are newly developed to address a designated data need. There are no formal international specifications governing the construction or use of Common Data Elements. Consequently, Common Data Elements tend to be made available by research communities on an empiric basis. Some limitations of Common Data Elements are that there may still be differences across studies in the interpretation and implementation of the Common Data Elements, variable validity in different populations, and inhibition by some existing research practices and the use of legacy data systems. Current National Institutes of Health efforts to support Common Data Element use are linked to the strengthening of National Institutes of Health Data Sharing policies and the investments in data repositories. Initiatives include cross-domain and domain-specific resources, construction of a Common Data Element Portal, and establishment of trans-National Institutes of Health working groups to address technical and implementation topics. The National Institutes of Health is seeking to lower the barriers to Common Data Element use through greater awareness and encourage the culture change necessary for their uptake and use. As National Institutes of Health, other agencies, professional societies, patient registries, and advocacy groups continue efforts to develop and promote the responsible use of Common Data Elements, particularly if linked to accepted data standards and terminologies, continued engagement with and feedback from the research community will remain important. © The Author(s) 2016.

Blade loss transient dynamics analysis, volume 2. Task 2: TETRA 2 user's manual

NASA Technical Reports Server (NTRS)

Black, Gerald; Gallardo, Vincente C.

1986-01-01

This is the user's manual for the TETRA 2 Computer Code, a program developed in the NASA-Lewis Blade Loss Program. TETRA 2 calculates a turbine engine's dynamic structural response from applied stimuli. The calculation options are: (1) transient response; and (2) steady state forced response. Based on the method of modal syntheses, the program allows the use of linear, as well as nonlinear connecting elements. Both transient and steady state options can include: flexible Bladed Disk Module, and Nonlinear Connecting Elements (including deadband, hardening/softening spring). The transient option has the additional capability to calculate response with a squeeze film bearing module. TETRA 2 output is summarized in a plotfile which permits post processing such as FFT or graphical animation with the proper software and computer equipment.

Machine Visual Motion Detection Modeled on Vertebrate Retina

DTIC Science & Technology

1988-01-01

18. NUMBER OF PAGES 9 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b . ABSTRACT unclassified c. THIS PAGE unclassified Standard Form...mechanism of direction selectivity. (a) shows the use of persistent lateral inhibition to block conduction in the null direction. ( b ) shows the use of...Bipolar elements Bipolar ( B ) elements compare the inputs from local receptor and horizontal elements, passing on the positive value of the difference

Anisotropic constitutive model for nickel base single crystal alloys: Development and finite element implementation

NASA Technical Reports Server (NTRS)

Dame, L. T.; Stouffer, D. C.

1986-01-01

A tool for the mechanical analysis of nickel base single crystal superalloys, specifically Rene N4, used in gas turbine engine components is developed. This is achieved by a rate dependent anisotropic constitutive model implemented in a nonlinear three dimensional finite element code. The constitutive model is developed from metallurigical concepts utilizing a crystallographic approach. A non Schmid's law formulation is used to model the tension/compression asymmetry and orientation dependence in octahedral slip. Schmid's law is a good approximation to the inelastic response of the material in cube slip. The constitutive equations model the tensile behavior, creep response, and strain rate sensitivity of these alloys. Methods for deriving the material constants from standard tests are presented. The finite element implementation utilizes an initial strain method and twenty noded isoparametric solid elements. The ability to model piecewise linear load histories is included in the finite element code. The constitutive equations are accurately and economically integrated using a second order Adams-Moulton predictor-corrector method with a dynamic time incrementing procedure. Computed results from the finite element code are compared with experimental data for tensile, creep and cyclic tests at 760 deg C. The strain rate sensitivity and stress relaxation capabilities of the model are evaluated.

Sieve element occlusion provides resistance against Aphis gossypii in TGR-1551 melons.

PubMed

Peng, Hsuan-Chieh; Walker, Gregory P

2018-05-30

Feeding behavior and plant response to feeding were studied for the aphid Aphis gossypii (Glover) on susceptible and resistant melons (cv. Iroquois and TGR-1551, respectively). Average phloem phase bout duration on TGR-1551 was <7% of the duration on Iroquois. Sixty-seven percent of aphids on TGR-1551 never produced a phloem phase that attained ingestion (EPG waveform E2) in contrast to only 7% of aphids on Iroquois. Average bout duration of waveform E2 (scored as zero if phloem phase did not attain E2) on TGR-1551 was <3% of the duration on Iroquois. Conversely, average bout duration of EPG waveform E1 (sieve element salivation) was 2.8 times greater on TGR-1551 than on Iroquois. In a second experiment, liquid nitrogen was used to rapidly cryofix leaves and aphids within a few minutes after the aphids penetrated a sieve element. Phloem near the penetration site was then examined by confocal laser scanning microscopy. Ninety-six percent of penetrated sieve elements were occluded by protein in TGR-1551 in contrast to only 28% in Iroquois. Usually in TGR-1551, occlusion was also observed in nearby non-penetrated sieve elements. Next, a calcium channel blocker, trivalent lanthanum, was used to prevent phloem occlusion in TGR-1551, and A. gossypii feeding behavior and the plant's phloem response were compared between lanthanum-treated and control TGR-1551. Lanthanum treatment eliminated the sieve element protein occlusion response and the aphids readily ingested phloem sap from treated plants. This study provides strong evidence that phloem occlusion is a mechanism for resistance against A. gossypii in TGR-1551. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Influence of mesh density, cortical thickness and material properties on human rib fracture prediction.

PubMed

Li, Zuoping; Kindig, Matthew W; Subit, Damien; Kent, Richard W

2010-11-01

The purpose of this paper was to investigate the sensitivity of the structural responses and bone fractures of the ribs to mesh density, cortical thickness, and material properties so as to provide guidelines for the development of finite element (FE) thorax models used in impact biomechanics. Subject-specific FE models of the second, fourth, sixth and tenth ribs were developed to reproduce dynamic failure experiments. Sensitivity studies were then conducted to quantify the effects of variations in mesh density, cortical thickness, and material parameters on the model-predicted reaction force-displacement relationship, cortical strains, and bone fracture locations for all four ribs. Overall, it was demonstrated that rib FE models consisting of 2000-3000 trabecular hexahedral elements (weighted element length 2-3mm) and associated quadrilateral cortical shell elements with variable thickness more closely predicted the rib structural responses and bone fracture force-failure displacement relationships observed in the experiments (except the fracture locations), compared to models with constant cortical thickness. Further increases in mesh density increased computational cost but did not markedly improve model predictions. A ±30% change in the major material parameters of cortical bone lead to a -16.7 to 33.3% change in fracture displacement and -22.5 to +19.1% change in the fracture force. The results in this study suggest that human rib structural responses can be modeled in an accurate and computationally efficient way using (a) a coarse mesh of 2000-3000 solid elements, (b) cortical shells elements with variable thickness distribution and (c) a rate-dependent elastic-plastic material model. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Experimental validation of a numerical model for subway induced vibrations

NASA Astrophysics Data System (ADS)

Gupta, S.; Degrande, G.; Lombaert, G.

2009-04-01

This paper presents the experimental validation of a coupled periodic finite element-boundary element model for the prediction of subway induced vibrations. The model fully accounts for the dynamic interaction between the train, the track, the tunnel and the soil. The periodicity or invariance of the tunnel and the soil in the longitudinal direction is exploited using the Floquet transformation, which allows for an efficient formulation in the frequency-wavenumber domain. A general analytical formulation is used to compute the response of three-dimensional invariant or periodic media that are excited by moving loads. The numerical model is validated by means of several experiments that have been performed at a site in Regent's Park on the Bakerloo line of London Underground. Vibration measurements have been performed on the axle boxes of the train, on the rail, the tunnel invert and the tunnel wall, and in the free field, both at the surface and at a depth of 15 m. Prior to these vibration measurements, the dynamic soil characteristics and the track characteristics have been determined. The Bakerloo line tunnel of London Underground has been modelled using the coupled periodic finite element-boundary element approach and free field vibrations due to the passage of a train at different speeds have been predicted and compared to the measurements. The correspondence between the predicted and measured response in the tunnel is reasonably good, although some differences are observed in the free field. The discrepancies are explained on the basis of various uncertainties involved in the problem. The variation in the response with train speed is similar for the measurements as well as the predictions. This study demonstrates the applicability of the coupled periodic finite element-boundary element model to make realistic predictions of the vibrations from underground railways.

An IFNG SNP with an estrogen-like response element selectively enhances promoter expression in peripheral but not lamina propria T cells.

PubMed

Gonsky, R; Deem, R L; Bream, J H; Young, H A; Targan, S R

2006-07-01

This study examines mucosa-specific regulatory pathways involved in modulation of interferon-gamma (IFN-gamma) in lamina propria T cells. Previous studies identified mucosa-specific CD2 cis-elements within the -204 to -108 bp IFNG promoter. Within this region, a single-site nucleotide polymorphism, -179G/T, imparts tumor necrosis factor-alpha stimulation of IFNG in peripheral blood lymphocytes, and is linked with accelerated AIDS progression. We discovered a putative estrogen response element (ERE) introduced by the -179T, which displays selective activation in peripheral blood mononuclear cells (PBMC) vs lamina propria mononuclear cells (LPMC). Transfection of PBMC with constructs containing the -179G or -179T site revealed CD2-mediated enhancement of the -179T compared to -179G allele, although, in LPMC, a similar level of expression was detected. Electrophoretic mobility shift assay (EMSA) analysis demonstrated CD2-mediated nucleoprotein binding to the -179T but not the -179G in PBMC. In LPMC, binding is constitutive to both -179G and -179T regions. Sequence and EMSA analysis suggests that the -179T allele creates an ERE-like binding site capable of binding recombinant estrogen receptor. Estrogen response element transactivation is enhanced by CD2 signaling, but inhibited by estrogen in PBMC but not in LPMC, although expression of estrogen receptor was similar. This is the first report to describe a potential molecular mechanism responsible for selectively controlling IFN-gamma production in LPMC.

Cloning the uteroglobin gene promoter from the relic volcano rabbit (Romerolagus diazi) reveals an ancient estrogen-response element.

PubMed

Acosta-MontesdeOca, Adriana; Zariñán, Teresa; Macías, Héctor; Pérez-Solís, Marco A; Ulloa-Aguirre, Alfredo; Gutiérrez-Sagal, Rubén

2012-05-01

To gain further insight on the estrogen-dependent transcriptional regulation of the uteroglobin (UG) gene, we cloned the 5'-flanking region of the UG gene from the phylogenetically ancient volcano rabbit (Romerolagus diazi; Rd). The cloned region spans 812 base pairs (bp; -812/-1) and contains a noncanonical TATA box (TACA). The translation start site is 48 bp downstream from the putative transcription initiation site (AGA), and is preceded by a consensus Kozak box. Comparison of the Rd-UG gene with that previously isolated from rabbits (Oryctolagus cuniculus) showed 93% in sequence identity as well as a number of conserved cis-acting elements, including the estrogen-response element (ERE; -265/-251), which differs from the consensus by two nucleotides. In MCF-7 cells, 17β-estradiol (E(2)) induced transcription of a luciferase reporter driven by the Rd-UG promoter in a similar manner as in an equivalent rabbit UG reporter; the Rd-UG promoter was 30% more responsive to E(2) than the rabbit promoter. Mutagenesis studies on the Rd-ERE confirmed this cis-element as a target of E(2) as two luciferase mutant reporters of the Rd-promoter, one with the rabbit and the other with the consensus ERE, were more responsive to the hormone than the wild-type reporter. Gel shift and super-shift assays showed that estrogen receptor-α indeed binds to the imperfect palindromic sequence of the Rd-ERE. Copyright © 2012 Wiley Periodicals, Inc.

Effect of randomness on multi-frequency aeroelastic responses resolved by Unsteady Adaptive Stochastic Finite Elements

NASA Astrophysics Data System (ADS)

Witteveen, Jeroen A. S.; Bijl, Hester

2009-10-01

The Unsteady Adaptive Stochastic Finite Elements (UASFE) method resolves the effect of randomness in numerical simulations of single-mode aeroelastic responses with a constant accuracy in time for a constant number of samples. In this paper, the UASFE framework is extended to multi-frequency responses and continuous structures by employing a wavelet decomposition pre-processing step to decompose the sampled multi-frequency signals into single-frequency components. The effect of the randomness on the multi-frequency response is then obtained by summing the results of the UASFE interpolation at constant phase for the different frequency components. Results for multi-frequency responses and continuous structures show a three orders of magnitude reduction of computational costs compared to crude Monte Carlo simulations in a harmonically forced oscillator, a flutter panel problem, and the three-dimensional transonic AGARD 445.6 wing aeroelastic benchmark subject to random fields and random parameters with various probability distributions.

Genome-wide targeted prediction of ABA responsive genes in rice based on over-represented cis-motif in co-expressed genes.

PubMed

Lenka, Sangram K; Lohia, Bikash; Kumar, Abhay; Chinnusamy, Viswanathan; Bansal, Kailash C

2009-02-01

Abscisic acid (ABA), the popular plant stress hormone, plays a key role in regulation of sub-set of stress responsive genes. These genes respond to ABA through specific transcription factors which bind to cis-regulatory elements present in their promoters. We discovered the ABA Responsive Element (ABRE) core (ACGT) containing CGMCACGTGB motif as over-represented motif among the promoters of ABA responsive co-expressed genes in rice. Targeted gene prediction strategy using this motif led to the identification of 402 protein coding genes potentially regulated by ABA-dependent molecular genetic network. RT-PCR analysis of arbitrarily chosen 45 genes from the predicted 402 genes confirmed 80% accuracy of our prediction. Plant Gene Ontology (GO) analysis of ABA responsive genes showed enrichment of signal transduction and stress related genes among diverse functional categories.

Model updating strategy for structures with localised nonlinearities using frequency response measurements

NASA Astrophysics Data System (ADS)

Wang, Xing; Hill, Thomas L.; Neild, Simon A.; Shaw, Alexander D.; Haddad Khodaparast, Hamed; Friswell, Michael I.

2018-02-01

This paper proposes a model updating strategy for localised nonlinear structures. It utilises an initial finite-element (FE) model of the structure and primary harmonic response data taken from low and high amplitude excitations. The underlying linear part of the FE model is first updated using low-amplitude test data with established techniques. Then, using this linear FE model, the nonlinear elements are localised, characterised, and quantified with primary harmonic response data measured under stepped-sine or swept-sine excitations. Finally, the resulting model is validated by comparing the analytical predictions with both the measured responses used in the updating and with additional test data. The proposed strategy is applied to a clamped beam with a nonlinear mechanism and good agreements between the analytical predictions and measured responses are achieved. Discussions on issues of damping estimation and dealing with data from amplitude-varying force input in the updating process are also provided.

Low and High Frequency Models of Response Statistics of a Cylindrical Orthogrid Vehicle Panel to Acoustic Excitation

NASA Technical Reports Server (NTRS)

Smith, Andrew; LaVerde, Bruce; Teague, David; Gardner, Bryce; Cotoni, Vincent

2010-01-01

This presentation further develops the orthogrid vehicle panel work. Employed Hybrid Module capabilities to assess both low/mid frequency and high frequency models in the VA One simulation environment. The response estimates from three modeling approaches are compared to ground test measurements. Detailed Finite Element Model of the Test Article -Expect to capture both the global panel modes and the local pocket mode response, but at a considerable analysis expense (time & resources). A Composite Layered Construction equivalent global stiffness approximation using SEA -Expect to capture response of the global panel modes only. An SEA approximation using the Periodic Subsystem Formulation. A finite element model of a single periodic cell is used to derive the vibroacoustic properties of the entire periodic structure (modal density, radiation efficiency, etc. Expect to capture response at various locations on the panel (on the skin and on the ribs) with less analysis expense

Compression Strength of Composite Primary Structural Components

NASA Technical Reports Server (NTRS)

Johnson, Eric R.

1998-01-01

Research conducted under NASA Grant NAG-1-537 focussed on the response and failure of advanced composite material structures for application to aircraft. Both experimental and analytical methods were utilized to study the fundamental mechanics of the response and failure of selected structural components subjected to quasi-static loads. Most of the structural components studied were thin-walled elements subject to compression, such that they exhibited buckling and postbuckling responses prior to catastrophic failure. Consequently, the analyses were geometrically nonlinear. Structural components studied were dropped-ply laminated plates, stiffener crippling, pressure pillowing of orthogonally stiffened cylindrical shells, axisymmetric response of pressure domes, and the static crush of semi-circular frames. Failure of these components motivated analytical studies on an interlaminar stress postprocessor for plate and shell finite element computer codes, and global/local modeling strategies in finite element modeling. These activities are summarized in the following section. References to literature published under the grant are listed on pages 5 to 10 by a letter followed by a number under the categories of journal publications, conference publications, presentations, and reports. These references are indicated in the text by their letter and number as a superscript.

OsDREB2A, a Rice Transcription Factor, Significantly Affects Salt Tolerance in Transgenic Soybean

PubMed Central

Ma, Qi-bin; Yang, Cun-yi; Mu, Ying-hui; Suo, Hai-cui; Luo, Lai-hui; Nian, Hai

2013-01-01

The dehydration responsive element binding (DREB) transcription factors play an important role in regulating stress-related genes. OsDREB2A, a member of the DREBP subfamily of AP2/ERF transcription factors in rice (Oryza sativa), is involved in the abiotic stress response. OsDREB2A expression is induced by drought, low-temperature and salt stresses. Here, we report the ability of OsDREB2A to regulate high-salt response in transgenic soybean. Overexpressing OsDREB2A in soybeans enhanced salt tolerance by accumulating osmolytes, such as soluble sugars and free proline, and improving the expression levels of some stress-responsive transcription factors and key genes. The phenotypic characterization of transgenic soybean were significantly better than those of wild-type (WT). Electrophoresis mobility shift assay (EMSA) revealed that the OsDREB2A can bind to the DRE core element in vitro. These results indicate that OsDREB2A may participate in abiotic stress by directly binding with DRE element to regulate the expression of downstream genes. Overexpression of OsDREB2A in soybean might be used to improve tolerance to salt stress. PMID:24376625

A Analysis of the Low Frequency Sound Field in Non-Rectangular Enclosures Using the Finite Element Method.

NASA Astrophysics Data System (ADS)

Geddes, Earl Russell

The details of the low frequency sound field for a rectangular room can be studied by the use of an established analytic technique--separation of variables. The solution is straightforward and the results are well-known. A non -rectangular room has boundary conditions which are not separable and therefore other solution techniques must be used. This study shows that the finite element method can be adapted for use in the study of sound fields in arbitrary shaped enclosures. The finite element acoustics problem is formulated and the modification of a standard program, which is necessary for solving acoustic field problems, is examined. The solution of the semi-non-rectangular room problem (one where the floor and ceiling remain parallel) is carried out by a combined finite element/separation of variables approach. The solution results are used to construct the Green's function for the low frequency sound field in five rooms (or data cases): (1) a rectangular (Louden) room; (2) The smallest wall of the Louden room canted 20 degrees from normal; (3) The largest wall of the Louden room canted 20 degrees from normal; (4) both the largest and the smallest walls are canted 20 degrees; and (5) a five-sided room variation of Case 4. Case 1, the rectangular room was calculated using both the finite element method and the separation of variables technique. The results for the two methods are compared in order to access the accuracy of the finite element method models. The modal damping coefficient are calculated and the results examined. The statistics of the source and receiver average normalized RMS P('2) responses in the 80 Hz, 100 Hz, and 125 Hz one-third octave bands are developed. The receiver averaged pressure response is developed to determine the effect of the source locations on the response. Twelve source locations are examined and the results tabulated for comparison. The effect of a finite sized source is looked at briefly. Finally, the standard deviation of the spatial pressure response is studied. The results for this characteristic show that it not significantly different in any of the rooms. The conclusions of the study are that only the frequency variations of the pressure response are affected by a room's shape. Further, in general, the simplest modification of a rectangular room (i.e., changing the angle of only one of the smallest walls), produces the most pronounced decrease of the pressure response variations in the low frequency region.

A fractional approach to the Fermi-Pasta-Ulam problem

NASA Astrophysics Data System (ADS)

Machado, J. A. T.

2013-09-01

This paper studies the Fermi-Pasta-Ulam problem having in mind the generalization provided by Fractional Calculus (FC). The study starts by addressing the classical formulation, based on the standard integer order differential calculus and evaluates the time and frequency responses. A first generalization to be investigated consists in the direct replacement of the springs by fractional elements of the dissipative type. It is observed that the responses settle rapidly and no relevant phenomena occur. A second approach consists of replacing the springs by a blend of energy extracting and energy inserting elements of symmetrical fractional order with amplitude modulated by quadratic terms. The numerical results reveal a response close to chaotic behaviour.

Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation. 1. Finite-Element Approximation of the Torsion Bar

NASA Astrophysics Data System (ADS)

Paimushin, V. N.; Shishkin, V. M.

2015-11-01

A prismatic semiquadratic element with a nonclassical approximation of its displacements is suggested for modeling the composite and soft layers of a torsion bar and multilayered plate-rod structures. The stiffness, weight, damping, and geometric stiffness matrices of the above-mentioned element are obtained. Expressions for computing stresses in the finite element under the action of static loads and vibrations in the resonance zone are presented. Test examples confirming the validity of the element suggested are given. An example of finite element determination of the dynamic response of a multilayered torsion bar in the resonant mode is considered.

Age-related decline in oligodendrogenesis retards white matter repair in mice.

PubMed

Miyamoto, Nobukazu; Pham, Loc-Duyen D; Hayakawa, Kazuhide; Matsuzaki, Toshinori; Seo, Ji Hae; Magnain, Caroline; Ayata, Cenk; Kim, Kyu-Won; Boas, David; Lo, Eng H; Arai, Ken

2013-09-01

Aging is one of the major risk factors for white matter injury in cerebrovascular disease. However, the effects of age on the mechanisms of injury/repair in white matter remain to be fully elucidated. Here, we ask whether, compared with young brains, white matter regions in older brains may be more vulnerable in part because of decreased rates of compensatory oligodendrogenesis after injury. A mouse model of prolonged cerebral hypoperfusion was prepared by bilateral common carotid artery stenosis in 2-month and 8-month-old mice. Matching in vitro studies were performed by subjecting oligodendrocyte precursor cells to sublethal 7-day CoCl2 treatment to induce chemical hypoxic stress. Baseline myelin density in the corpus callosum was similar in 2-month and 8-month-old mice. But after induction of prolonged cerebral hypoperfusion, older mice showed more severe white matter injury together with worse deficits in working memory. The numbers of newborn oligodendrocytes and their precursors were increased by cerebral hypoperfusion in young mice, whereas these endogenous responses were significantly dampened in older mice. Defects in cyclic AMP response element-binding protein signaling may be involved because activating cyclic AMP response element-binding protein with the type-III phosphodiesterase inhibitor cilostazol in older mice restored the differentiation of oligodendrocyte precursor cells, alleviated myelin loss, and improved cognitive dysfunction during cerebral hypoperfusion. Cell culture systems confirmed that cilostazol promoted the differentiation of oligodendrocyte precursor cells. An age-related decline in cyclic AMP response element-binding protein-mediated oligodendrogenesis may compromise endogenous white matter repair mechanisms, and therefore, drugs that activate cyclic AMP response element-binding protein signaling provide a potential therapeutic approach for treating white matter injury in aging brains.

Simultaneous shifts in elemental stoichiometry and fatty acids of Emiliania huxleyi in response to environmental changes

NASA Astrophysics Data System (ADS)

Bi, Rong; Ismar, Stefanie M. H.; Sommer, Ulrich; Zhao, Meixun

2018-02-01

Climate-driven changes in environmental conditions have significant and complex effects on marine ecosystems. Variability in phytoplankton elements and biochemicals can be important for global ocean biogeochemistry and ecological functions, while there is currently limited understanding on how elements and biochemicals respond to the changing environments in key coccolithophore species such as Emiliania huxleyi. We investigated responses of elemental stoichiometry and fatty acids (FAs) in a strain of E. huxleyi under three temperatures (12, 18 and 24 °C), three N : P supply ratios (molar ratios 10:1, 24:1 and 63:1) and two pCO2 levels (560 and 2400 µatm). Overall, C : N : P stoichiometry showed the most pronounced response to N : P supply ratios, with high ratios of particulate organic carbon vs. particulate organic nitrogen (POC : PON) and low ratios of PON vs. particulate organic phosphorus (PON : POP) in low-N media, and high POC : POP and PON : POP in low-P media. The ratio of particulate inorganic carbon vs. POC (PIC : POC) and polyunsaturated fatty acid proportions strongly responded to temperature and pCO2, both being lower under high pCO2 and higher with warming. We observed synergistic interactions between warming and nutrient deficiency (and high pCO2) on elemental cellular contents and docosahexaenoic acid (DHA) proportion in most cases, indicating the enhanced effect of warming under nutrient deficiency (and high pCO2). Our results suggest differential sensitivity of elements and FAs to the changes in temperature, nutrient availability and pCO2 in E. huxleyi, which is to some extent unique compared to non-calcifying algal classes. Thus, simultaneous changes of elements and FAs should be considered when predicting future roles of E. huxleyi in the biotic-mediated connection between biogeochemical cycles, ecological functions and climate change.

Three dimensional modeling of rigid pavement : executive summary, February 1995.

DOT National Transportation Integrated Search

1995-02-17

A finite-element program has been developed to model the response of rigid pavement to both static loads and temperature changes. The program is fully three-dimensional and incorporates not only the common twenty-node brick element but also a thin in...

Three-dimensional modeling of rigid pavement : final report, September 1995.

DOT National Transportation Integrated Search

1995-02-17

A finite-element program has been developed to model the response of rigid pavement to both static loads and temperature changes. The program is fully three-dimensional and incorporates not only the common twenty-node brick element but also a thin in...

A Finite Element Model of the THOR-K Dummy for Aerospace and Aircraft Impact Simulations

NASA Technical Reports Server (NTRS)

Putnam, Jacob; Untaroiu, Costin D.; Somers, Jeffrey T.; Pellettiere, Joseph

2013-01-01

1) Update and Improve the THOR Finite Element (FE) model to specifications of the latest mod kit (THOR-K). 2) Evaluate the kinematic and kinetic response of the FE model in frontal, spinal, and lateral impact loading conditions.

An Empirical Correction Method for Improving off-Axes Response Prediction in Component Type Flight Mechanics Helicopter Models

NASA Technical Reports Server (NTRS)

Mansur, M. Hossein; Tischler, Mark B.

1997-01-01

Historically, component-type flight mechanics simulation models of helicopters have been unable to satisfactorily predict the roll response to pitch stick input and the pitch response to roll stick input off-axes responses. In the study presented here, simple first-order low-pass filtering of the elemental lift and drag forces was considered as a means of improving the correlation. The method was applied to a blade-element model of the AH-64 APache, and responses of the modified model were compared with flight data in hover and forward flight. Results indicate that significant improvement in the off-axes responses can be achieved in hover. In forward flight, however, the best correlation in the longitudinal and lateral off-axes responses required different values of the filter time constant for each axis. A compromise value was selected and was shown to result in good overall improvement in the off-axes responses. The paper describes both the method and the model used for its implementation, and presents results obtained at hover and in forward flight.

Identification of an enhancer element of class Pi glutathione S-transferase gene required for expression by a co-planar polychlorinated biphenyl.

PubMed Central

Matsumoto, M; Imagawa, M; Aoki, Y

1999-01-01

3,3',4,4',5-Pentachlorobiphenyl (PenCB), one of the most toxic co-planar polychlorinated biphenyl congeners, specifically induces class Pi glutathione S-transferase (GSTP1) as well as cytochrome P-450 1A1 in primary cultured rat liver parenchymal cells [Aoki, Matsumoto and Suzuki (1993) FEBS Lett. 333, 114-118]. However, the 5'-flanking sequence of the GSTP1 gene does not contain a xenobiotic responsive element, to which arylhydrocarbon receptor binds. Using a chloramphenicol acetyltransferase assay we demonstrate here that the enhancer termed GSTP1 enhancer I (GPEI) is necessary for the stimulation by PenCB of GSTP1 gene expression in primary cultured rat liver parenchymal cells. GPEI is already known to contain a dyad of PMA responsive element-like elements oriented palindromically. It is suggested that a novel signal transduction pathway activated by PenCB contributes to the stimulation of GSTP1 expression. PMID:10051428

Perceptions on the essential competencies for intraprofessional practice.

PubMed

Jelley, Wilma; Larocque, Nathalie; Borghese, Michael

2013-01-01

To gather the perspectives of physiotherapists and physiotherapist assistants on essential competencies for intraprofessional (physiotherapist-physiotherapist assistant) collaboration. A survey was developed to gather physiotherapist and physiotherapist assistant perceptions of the essential elements of effective and efficient intraprofessional collaborative practice. Participants were asked to rate the importance of 36 elements in 6 different categories (communication, collaboration, consultation, assignment of tasks, conflict management, and roles/responsibilities) involved in intraprofessional practice. A total of 1049 physiotherapists and 121 physiotherapist assistants responded to the survey. Analysis identified 10 competency elements perceived by participants as essential to effective and efficient intraprofessional collaboration. Comparisons using demographic variables consistently yielded the same top 10 elements. Our results indicated that physiotherapists and physiotherapist assistants working in private and public practice share very similar views on what is essential for effective intraprofessional practice. The consensus is that communication is key; open lines of communication help to determine responsibilities. Physiotherapy pre-licensure and continuing education programmes should include opportunities to work on communication, listening, and the skills needed to interact and collaborate effectively.

Genomic organization, complete sequence, and chromosomal location of the gene for human eotaxin (SCYA11), an eosinophil-specific CC chemokine

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

Garcia-Zepeda, E.A.; Sarafi, M.N.; Luster, A.D.

1997-05-01

Eotaxin is a CC chemokine that is a specific chemoattractant for eosinophils and is implicated in the pathogenesis of eosinophilic inflammatory diseases, such as asthma. We describe the genomic organization, complete sequence, including 1354 bp 5{prime} of the RNA initiation site, and chromosomal localization of the human eotaxin gene. Fluorescence in situ hybridization analysis localized eotaxin to human chromosome 17, in the region q21.1-q21.2, and the human gene name SCYA11 was assigned. We also present the 5{prime} flanking sequence of the mouse eotaxin gene and have identified several regulatory elements that are conserved between the murine and the human promoters.more » In particular, the presence of elements such as NF-{Kappa}B, interferon-{gamma} response element, and glucocorticoid response element may explain the observed regulation of the eotaxin gene by cytokines and glucocorticoids. 17 refs., 4 figs., 1 tab.« less

Exploiting symmetries in the modeling and analysis of tires

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Andersen, Carl M.; Tanner, John A.

1987-01-01

A simple and efficient computational strategy for reducing both the size of a tire model and the cost of the analysis of tires in the presence of symmetry-breaking conditions (unsymmetry in the tire material, geometry, or loading) is presented. The strategy is based on approximating the unsymmetric response of the tire with a linear combination of symmetric and antisymmetric global approximation vectors (or modes). Details are presented for the three main elements of the computational strategy, which include: use of special three-field mixed finite-element models, use of operator splitting, and substantial reduction in the number of degrees of freedom. The proposed computational stategy is applied to three quasi-symmetric problems of tires: linear analysis of anisotropic tires, through use of semianalytic finite elements, nonlinear analysis of anisotropic tires through use of two-dimensional shell finite elements, and nonlinear analysis of orthotropic tires subjected to unsymmetric loading. Three basic types of symmetry (and their combinations) exhibited by the tire response are identified.

Investigation of a Macromechanical Approach to Analyzing Triaxially-Braided Polymer Composites

NASA Technical Reports Server (NTRS)

Goldberg, Robert K.; Blinzler, Brina J.; Binienda, Wieslaw K.

2010-01-01

A macro level finite element-based model has been developed to simulate the mechanical and impact response of triaxially-braided polymer matrix composites. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. The material stiffness and strength values required for the constitutive model are determined based on coupon level tests on the braided composite. Simulations of quasi-static coupon tests of a representative braided composite are conducted. Varying the strength values that are input to the material model is found to have a significant influence on the effective material response predicted by the finite element analysis, sometimes in ways that at first glance appear non-intuitive. A parametric study involving the input strength parameters provides guidance on how the analysis model can be improved.

Active noise control using noise source having adaptive resonant frequency tuning through stiffness variation

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Hedeen, Robert A. (Inventor); Pla, Frederic G. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by a plurality of force transmitting mechanisms which contact the noise radiating element. Each one of the force transmitting mechanisms includes an expandable element and a spring in contact with the noise radiating element so that excitation of the element varies the spring force applied to the noise radiating element. The elements are actuated by a controller which receives input of a signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the spring force applied to the noise radiating element to be varied. The force transmitting mechanisms can be arranged to either produce bending or linear stiffness variations in the noise radiating element.

Multipolar Coupling in Hybrid Metal–Dielectric Metasurfaces

DOE PAGES

Guo, Rui; Rusak, Evgenia; Staude, Isabelle; ...

2016-03-02

In this paper, we study functional hybrid metasurfaces consisting of metal–dielectric nanoantennas that direct light from an incident plane wave or from localized light sources into a preferential direction. The directionality is obtained by carefully balancing the multipolar contributions to the scattering response from the constituents of the metasurface. The hybrid nanoantennas are composed of a plasmonic gold nanorod acting as a feed element and a silicon nanodisk acting as a director element. In order to experimentally realize this design, we have developed a two-step electron-beam lithography process in combination with a precision alignment step. Finally, the optical response ofmore » the fabricated sample is measured and reveals distinct signatures of coupling between the plasmonic and the dielectric nanoantenna elements that ultimately leads to unidirectional radiation of light.« less

Inelastic behavior of structural components

NASA Technical Reports Server (NTRS)

Hussain, N.; Khozeimeh, K.; Toridis, T. G.

1980-01-01

A more accurate procedure was developed for the determination of the inelastic behavior of structural components. The actual stress-strain curve for the mathematical of the structure was utilized to generate the force-deformation relationships for the structural elements, rather than using simplified models such as elastic-plastic, bilinear and trilinear approximations. relationships were generated for beam elements with various types of cross sections. In the generational of these curves, stress or load reversals, kinematic hardening and hysteretic behavior were taken into account. Intersections between loading and unloading branches were determined through an iterative process. Using the inelastic properties obtained, the plastic static response of some simple structural systems composed of beam elements was computed. Results were compared with known solutions, indicating a considerable improvement over response predictions obtained by means of simplified approximations used in previous investigations.

Three-Dimensional Finite Element Ablative Thermal Response and Thermostructural Design of Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Dec, John A.; Braun, Robert D.

2011-01-01

A finite element ablation and thermal response program is presented for simulation of three-dimensional transient thermostructural analysis. The three-dimensional governing differential equations and finite element formulation are summarized. A novel probabilistic design methodology for thermal protection systems is presented. The design methodology is an eight step process beginning with a parameter sensitivity study and is followed by a deterministic analysis whereby an optimum design can determined. The design process concludes with a Monte Carlo simulation where the probabilities of exceeding design specifications are estimated. The design methodology is demonstrated by applying the methodology to the carbon phenolic compression pads of the Crew Exploration Vehicle. The maximum allowed values of bondline temperature and tensile stress are used as the design specifications in this study.

A role for circadian evening elements in cold-regulated gene expression in Arabidopsis.

PubMed

Mikkelsen, Michael D; Thomashow, Michael F

2009-10-01

The plant transcriptome is dramatically altered in response to low temperature. The cis-acting DNA regulatory elements and trans-acting factors that regulate the majority of cold-regulated genes are unknown. Previous bioinformatic analysis has indicated that the promoters of cold-induced genes are enriched in the Evening Element (EE), AAAATATCT, a DNA regulatory element that has a role in circadian-regulated gene expression. Here we tested the role of EE and EE-like (EEL) elements in cold-induced expression of two Arabidopsis genes, CONSTANS-like 1 (COL1; At5g54470) and a gene encoding a 27-kDa protein of unknown function that we designated COLD-REGULATED GENE 27 (COR27; At5g42900). Mutational analysis indicated that the EE/EEL elements were required for cold induction of COL1 and COR27, and that their action was amplified through coupling with ABA response element (ABRE)-like (ABREL) motifs. An artificial promoter consisting solely of four EE motifs interspersed with three ABREL motifs was sufficient to impart cold-induced gene expression. Both COL1 and COR27 were found to be regulated by the circadian clock at warm growth temperatures and cold-induction of COR27 was gated by the clock. These results suggest that cold- and clock-regulated gene expression are integrated through regulatory proteins that bind to EE and EEL elements supported by transcription factors acting at ABREL sequences. Bioinformatic analysis indicated that the coupling of EE and EEL motifs with ABREL motifs is highly enriched in cold-induced genes and thus may constitute a DNA regulatory element pair with a significant role in configuring the low-temperature transcriptome.

Foundations of Responsibility for Children

ERIC Educational Resources Information Center

Dillen, Annemie

2008-01-01

Children's vulnerability asks for people taking up responsibility for children. In this contribution, three different ways of thinking on foundations of (ethical and spiritual) responsibility for children are discussed, namely, a liberalist, a social-constructivist and a naturalist paradigm. The author argues that cultural and natural elements are…

Music K-6.

ERIC Educational Resources Information Center

New York State Education Dept., Albany. Bureau of Elementary Curriculum Development.

The primary function of music education is the development of a responsiveness to the artistic qualities of sound. The constituent elements fundamental to musical response are rhythm, melody, harmony, form, expression, and style. With the goal of developing a responsiveness consisting of musicality and affective growth, this guide has been…

Dynamic Response of a Planetary Gear System Using a Finite Element/Contact Mechanics Model

NASA Technical Reports Server (NTRS)

Parker, Robert G.; Agashe, Vinayak; Vijayakar, Sandeep M.

2000-01-01

The dynamic response of a helicopter planetary gear system is examined over a wide range of operating speeds and torques. The analysis tool is a unique, semianalytical finite element formulation that admits precise representation of the tooth geometry and contact forces that are crucial in gear dynamics. Importantly, no a priori specification of static transmission error excitation or mesh frequency variation is required; the dynamic contact forces are evaluated internally at each time step. The calculated response shows classical resonances when a harmonic of mesh frequency coincides with a natural frequency. However, peculiar behavior occurs where resonances expected to be excited at a given speed are absent. This absence of particular modes is explained by analytical relationships that depend on the planetary configuration and mesh frequency harmonic. The torque sensitivity of the dynamic response is examined and compared to static analyses. Rotation mode response is shown to be more sensitive to input torque than translational mode response.

A Role for the GCC-Box in Jasmonate-Mediated Activation of the PDF1.2 Gene of Arabidopsis1

PubMed Central

Brown, Rebecca L.; Kazan, Kemal; McGrath, Ken C.; Maclean, Don J.; Manners, John M.

2003-01-01

The PDF1.2 gene of Arabidopsis encoding a plant defensin is commonly used as a marker for characterization of the jasmonate-dependent defense responses. Here, using PDF1.2 promoter-deletion lines linked to the β-glucoronidase-reporter gene, we examined putative promoter elements associated with jasmonate-responsive expression of this gene. Using stably transformed plants, we first characterized the extended promoter region that positively regulates basal expression from the PDF1.2 promoter. Second, using promoter deletion constructs including one from which the GCC-box region was deleted, we observed a substantially lower response to jasmonate than lines carrying this motif. In addition, point mutations introduced into the core GCC-box sequence substantially reduced jasmonate responsiveness, whereas addition of a 20-nucleotide-long promoter element carrying the core GCC-box and flanking nucleotides provided jasmonate responsiveness to a 35S minimal promoter. Taken together, these results indicated that the GCC-box plays a key role in conferring jasmonate responsiveness to the PDF1.2 promoter. However, deletion or specific mutations introduced into the core GCC-box did not completely abolish the jasmonate responsiveness of the promoter, suggesting that the other promoter elements lying downstream from the GCC-box region may also contribute to jasmonate responsiveness. In other experiments, we identified a jasmonate- and pathogen-responsive ethylene response factor transcription factor, AtERF2, which when overexpressed in transgenic Arabidopsis plants activated transcription from the PDF1.2, Thi2.1, and PR4 (basic chitinase) genes, all of which contain a GCC-box sequence in their promoters. Our results suggest that in addition to their roles in regulating ethylene-mediated gene expression, ethylene response factors also appear to play important roles in regulating jasmonate-responsive gene expression, possibly via interaction with the GCC-box. PMID:12805630

In silico analysis of cis-acting regulatory elements in 5' regulatory regions of sucrose transporter gene families in rice (Oryza sativa Japonica) and Arabidopsis thaliana.

PubMed

Ibraheem, Omodele; Botha, Christiaan E J; Bradley, Graeme

2010-12-01

The regulation of gene expression involves a multifarious regulatory system. Each gene contains a unique combination of cis-acting regulatory sequence elements in the 5' regulatory region that determines its temporal and spatial expression. Cis-acting regulatory elements are essential transcriptional gene regulatory units; they control many biological processes and stress responses. Thus a full understanding of the transcriptional gene regulation system will depend on successful functional analyses of cis-acting elements. Cis-acting regulatory elements present within the 5' regulatory region of the sucrose transporter gene families in rice (Oryza sativa Japonica cultivar-group) and Arabidopsis thaliana, were identified using a bioinformatics approach. The possible cis-acting regulatory elements were predicted by scanning 1.5kbp of 5' regulatory regions of the sucrose transporter genes translational start sites, using Plant CARE, PLACE and Genomatix Matinspector professional databases. Several cis-acting regulatory elements that are associated with plant development, plant hormonal regulation and stress response were identified, and were present in varying frequencies within the 1.5kbp of 5' regulatory region, among which are; A-box, RY, CAT, Pyrimidine-box, Sucrose-box, ABRE, ARF, ERE, GARE, Me-JA, ARE, DRE, GA-motif, GATA, GT-1, MYC, MYB, W-box, and I-box. This result reveals the probable cis-acting regulatory elements that possibly are involved in the expression and regulation of sucrose transporter gene families in rice and Arabidopsis thaliana during cellular development or environmental stress conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Finite Element Analysis of Geodesically Stiffened Cylindrical Composite Shells Using a Layerwise Theory

NASA Technical Reports Server (NTRS)

Gerhard, Craig Steven; Gurdal, Zafer; Kapania, Rakesh K.

1996-01-01

Layerwise finite element analyses of geodesically stiffened cylindrical shells are presented. The layerwise laminate theory of Reddy (LWTR) is developed and adapted to circular cylindrical shells. The Ritz variational method is used to develop an analytical approach for studying the buckling of simply supported geodesically stiffened shells with discrete stiffeners. This method utilizes a Lagrange multiplier technique to attach the stiffeners to the shell. The development of the layerwise shells couples a one-dimensional finite element through the thickness with a Navier solution that satisfies the boundary conditions. The buckling results from the Ritz discrete analytical method are compared with smeared buckling results and with NASA Testbed finite element results. The development of layerwise shell and beam finite elements is presented and these elements are used to perform the displacement field, stress, and first-ply failure analyses. The layerwise shell elements are used to model the shell skin and the layerwise beam elements are used to model the stiffeners. This arrangement allows the beam stiffeners to be assembled directly into the global stiffness matrix. A series of analytical studies are made to compare the response of geodesically stiffened shells as a function of loading, shell geometry, shell radii, shell laminate thickness, stiffener height, and geometric nonlinearity. Comparisons of the structural response of geodesically stiffened shells, axial and ring stiffened shells, and unstiffened shells are provided. In addition, interlaminar stress results near the stiffener intersection are presented. First-ply failure analyses for geodesically stiffened shells utilizing the Tsai-Wu failure criterion are presented for a few selected cases.

Moving toward quality palliative cancer care: parent and clinician perspectives on gaps between what matters and what is accessible.

PubMed

Kassam, Alisha; Skiadaresis, Julia; Habib, Sharifa; Alexander, Sarah; Wolfe, Joanne

2013-03-01

The National Consensus Project (NCP) published a set of standards for quality palliative care delivery. A key step before applying these guidelines to pediatric oncology is to evaluate how much families and clinicians value these standards. We aimed to determine which elements of palliative care are considered important according to bereaved parents and pediatric oncology clinicians and to determine accessibility of these elements. We administered questionnaires to 75 bereaved parents (response rate, 54%) and 48 pediatric oncology clinicians (response rate, 91%) at a large teaching hospital. Outcome measures included importance ratings and accessibility of core elements of palliative care delivery. Fifteen of 20 core elements were highly valued by both parents and clinicians (defined as > 60% of parents and clinicians reporting the item as important). Compared with clinicians, parents gave higher ratings to receiving cancer-directed therapy during the last month of life (P < .01) and involvement of a spiritual mentor (P = .03). Of the valued elements, only three were accessible more than 60% of the time according to clinicians and parents. Valued elements least likely to be accessible included a direct admission policy to hospital, sibling support, and parent preparation for medical aspects surrounding death. Parents and clinicians highly value a majority of palliative care elements described in the NCP framework. Children with advanced cancer may not be receiving key elements of palliative care despite parents and clinicians recognizing them as important. Evaluation of barriers to provision of quality palliative care and strategies for overcoming them are critical.

Effect of HF Heating Array Directivity Pattern on the Frequency Response of Generated ELF/VLF.

DTIC Science & Technology

1983-01-01

radiators ....... ............ 4 1-2 HF heating array ........ ................... 9 1-3 HF heating array element ...... ................ 9 1-4 View of top...elements looking down at pyramid ....... 9 1-5 Non-planar log-periodic antenna semi-structure dimensions ............ . ....... 10 l-6a Power gain vs...22 1-8 Orientation of 4- and 8-element arrays .. ......... .. 24 1- 9 Comparison of experimental and theoretical patterns. . . 27 1-10 Directive

Evaluation of a Progressive Failure Analysis Methodology for Laminated Composite Structures

NASA Technical Reports Server (NTRS)

Sleight, David W.; Knight, Norman F., Jr.; Wang, John T.

1997-01-01

A progressive failure analysis methodology has been developed for predicting the nonlinear response and failure of laminated composite structures. The progressive failure analysis uses C plate and shell elements based on classical lamination theory to calculate the in-plane stresses. Several failure criteria, including the maximum strain criterion, Hashin's criterion, and Christensen's criterion, are used to predict the failure mechanisms. The progressive failure analysis model is implemented into a general purpose finite element code and can predict the damage and response of laminated composite structures from initial loading to final failure.

Analytical and Numerical Results for an Adhesively Bonded Joint Subjected to Pure Bending

NASA Technical Reports Server (NTRS)

Smeltzer, Stanley S., III; Lundgren, Eric

2006-01-01

A one-dimensional, semi-analytical methodology that was previously developed for evaluating adhesively bonded joints composed of anisotropic adherends and adhesives that exhibit inelastic material behavior is further verified in the present paper. A summary of the first-order differential equations and applied joint loading used to determine the adhesive response from the methodology are also presented. The method was previously verified against a variety of single-lap joint configurations from the literature that subjected the joints to cases of axial tension and pure bending. Using the same joint configuration and applied bending load presented in a study by Yang, the finite element analysis software ABAQUS was used to further verify the semi-analytical method. Linear static ABAQUS results are presented for two models, one with a coarse and one with a fine element meshing, that were used to verify convergence of the finite element analyses. Close agreement between the finite element results and the semi-analytical methodology were determined for both the shear and normal stress responses of the adhesive bondline. Thus, the semi-analytical methodology was successfully verified using the ABAQUS finite element software and a single-lap joint configuration subjected to pure bending.

An analysis of cross-coupling of a multicomponent jet engine test stand using finite element modeling techniques

NASA Technical Reports Server (NTRS)

Schweikhard, W. G.; Singnoi, W. N.

1985-01-01

A two axis thrust measuring system was analyzed by using a finite a element computer program to determine the sensitivities of the thrust vectoring nozzle system to misalignment of the load cells and applied loads, and the stiffness of the structural members. Three models were evaluated: (1) the basic measuring element and its internal calibration load cells; (2) the basic measuring element and its external load calibration equipment; and (3) the basic measuring element, external calibration load frame and the altitude facility support structure. Alignment of calibration loads was the greatest source of error for multiaxis thrust measuring systems. Uniform increases or decreases in stiffness of the members, which might be caused by the selection of the materials, have little effect on the accuracy of the measurements. It is found that the POLO-FINITE program is a viable tool for designing and analyzing multiaxis thrust measurement systems. The response of the test stand to step inputs that might be encountered with thrust vectoring tests was determined. The dynamic analysis show a potential problem for measuring the dynamic response characteristics of thrust vectoring systems because of the inherently light damping of the test stand.

Robust Translation of the Nucleoid Protein Fis Requires a Remote Upstream AU Element and Is Enhanced by RNA Secondary Structure

PubMed Central

Nafissi, Maryam; Chau, Jeannette; Xu, Jimin

2012-01-01

Synthesis of the Fis nucleoid protein rapidly increases in response to nutrient upshifts, and Fis is one of the most abundant DNA binding proteins in Escherichia coli under nutrient-rich growth conditions. Previous work has shown that control of Fis synthesis occurs at transcription initiation of the dusB-fis operon. We show here that while translation of the dihydrouridine synthase gene dusB is low, unusual mechanisms operate to enable robust translation of fis. At least two RNA sequence elements located within the dusB coding region are responsible for high fis translation. The most important is an AU element centered 35 nucleotides (nt) upstream of the fis AUG, which may function as a binding site for ribosomal protein S1. In addition, a 44-nt segment located upstream of the AU element and predicted to form a stem-loop secondary structure plays a prominent role in enhancing fis translation. On the other hand, mutations close to the AUG, including over a potential Shine-Dalgarno sequence, have little effect on Fis protein levels. The AU element and stem-loop regions are phylogenetically conserved within dusB-fis operons of representative enteric bacteria. PMID:22389479

Finite Elements Analysis of a Composite Semi-Span Test Article With and Without Discrete Damage

NASA Technical Reports Server (NTRS)

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

2000-01-01

AS&M Inc. performed finite element analysis, with and without discrete damage, of a composite semi-span test article that represents the Boeing 220-passenger transport aircraft composite semi-span test article. A NASTRAN bulk data file and drawings of the test mount fixtures and semi-span components were utilized to generate the baseline finite element model. In this model, the stringer blades are represented by shell elements, and the stringer flanges are combined with the skin. Numerous modeling modifications and discrete source damage scenarios were applied to the test article model throughout the course of the study. This report details the analysis method and results obtained from the composite semi-span study. Analyses were carried out for three load cases: Braked Roll, LOG Down-Bending and 2.5G Up-Bending. These analyses included linear and nonlinear static response, as well as linear and nonlinear buckling response. Results are presented in the form of stress and strain plots. factors of safety for failed elements, buckling loads and modes, deflection prediction tables and plots, and strainage prediction tables and plots. The collected results are presented within this report for comparison to test results.

Combined tension and bending testing of tapered composite laminates

NASA Astrophysics Data System (ADS)

O'Brien, T. Kevin; Murri, Gretchen B.; Hagemeier, Rick; Rogers, Charles

1994-11-01

A simple beam element used at Bell Helicopter was incorporated in the Computational Mechanics Testbed (COMET) finite element code at the Langley Research Center (LaRC) to analyze the responce of tappered laminates typical of flexbeams in composite rotor hubs. This beam element incorporated the influence of membrane loads on the flexural response of the tapered laminate configurations modeled and tested in a combined axial tension and bending (ATB) hydraulic load frame designed and built at LaRC. The moments generated from the finite element model were used in a tapered laminated plate theory analysis to estimate axial stresses on the surface of the tapered laminates due to combined bending and tension loads. Surfaces strains were calculated and compared to surface strains measured using strain gages mounted along the laminate length. The strain distributions correlated reasonably well with the analysis. The analysis was then used to examine the surface strain distribution in a non-linear tapered laminate where a similarly good correlation was obtained. Results indicate that simple finite element beam models may be used to identify tapered laminate configurations best suited for simulating the response of a composite flexbeam in a full scale rotor hub.

Superconducting multiport antenna arrays

NASA Astrophysics Data System (ADS)

Chaloupka, H.

1993-10-01

Applications of HTS to radiating elements and beam-forming networks of multibeam and/or multifrequency arrays are discussed. This includes radiating elements which meet special requirements with respect to size and frequency response. Realized versions of both a three-port HTS array and a 4 x 4 Butler matrix are presented.

48 CFR 609.406-3 - Procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... statement from each DOS organizational element affected by the debarment action as to the impact of a... is responsible for making the transcribed record of the hearing, unless the contractor and the fact... decision to each DOS organizational element affected by the decision and to the General Services...

Sports Fields: A Manual for Design Construction and Maintenance.

ERIC Educational Resources Information Center

Puhalla, Jim; Krans, Jeff; Goatley, Mike

Comprehensive technical reference information is provided for those responsible for the design, construction, renovation, or maintenance of sports grounds. Chapters illustrate specific design elements of all popular sports facilities, and explain how those elements are integrated in a successful project; explore commonly encountered sports field…

Estrogen regulation of chicken riboflavin carrier protein gene is mediated by ERE half sites without direct binding of estrogen receptor.

PubMed

Bahadur, Urvashi; Ganjam, Goutham K; Vasudevan, Nandini; Kondaiah, Paturu

2005-02-28

Estrogen is an important steroid hormone that mediates most of its effects on regulation of gene expression by binding to intracellular receptors. The consensus estrogen response element (ERE) is a 13bp palindromic inverted repeat with a three nucleotide spacer. However, several reports suggest that many estrogen target genes are regulated by diverse elements, such as imperfect EREs and ERE half sites (ERE 1/2), which are either the proximal or the distal half of the palindrome. To gain more insight into ERE half site-mediated gene regulation, we used a region from the estrogen-regulated chicken riboflavin carrier protein (RCP) gene promoter that contains ERE half sites. Using moxestrol, an analogue of estrogen and transient transfection of deletion and mutation containing RCP promoter/reporter constructs in chicken hepatoma (LMH2A) cells, we identified an estrogen response unit (ERU) composed of two consensus ERE 1/2 sites and one non-consensus ERE 1/2 site. Mutation of any of these sites within this ERU abolishes moxestrol response. Further, the ERU is able to confer moxestrol responsiveness to a heterologous promoter. Interestingly, RCP promoter is regulated by moxestrol in estrogen responsive human MCF-7 cells, but not in other cell lines such as NIH3T3 and HepG2 despite estrogen receptor-alpha (ER-alpha) co transfection. Electrophoretic mobility shift assays (EMSAs) with promoter regions encompassing the half sites and nuclear extracts from LMH2A cells show the presence of a moxestrol-induced complex that is abolished by a polyclonal anti-ERalpha antibody. Surprisingly, estrogen receptor cannot bind to these promoter elements in isolation. Thus, there appears to be a definite requirement for some other factor(s) in addition to estrogen receptor, for the generation of a suitable response of this promoter to estrogen. Our studies therefore suggest a novel mechanism of gene regulation by estrogen, involving ERE half sites without direct binding of ER to the cognate elements.

An ABRE promoter sequence is involved in osmotic stress-responsive expression of the DREB2A gene, which encodes a transcription factor regulating drought-inducible genes in Arabidopsis.

PubMed

Kim, June-Sik; Mizoi, Junya; Yoshida, Takuya; Fujita, Yasunari; Nakajima, Jun; Ohori, Teppei; Todaka, Daisuke; Nakashima, Kazuo; Hirayama, Takashi; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2011-12-01

In plants, osmotic stress-responsive transcriptional regulation depends mainly on two major classes of cis-acting elements found in the promoter regions of stress-inducible genes: ABA-responsive elements (ABREs) and dehydration-responsive elements (DREs). ABRE has been shown to perceive ABA-mediated osmotic stress signals, whereas DRE is known to be involved in an ABA-independent pathway. Previously, we reported that the transcription factor DRE-BINDING PROTEIN 2A (DREB2A) regulates DRE-mediated transcription of target genes under osmotic stress conditions in Arabidopsis (Arabidopsis thaliana). However, the transcriptional regulation of DREB2A itself remains largely uncharacterized. To elucidate the transcriptional mechanism associated with the DREB2A gene under osmotic stress conditions, we generated a series of truncated and base-substituted variants of the DREB2A promoter and evaluated their transcriptional activities individually. We found that both ABRE and coupling element 3 (CE3)-like sequences located approximately -100 bp from the transcriptional initiation site are necessary for the dehydration-responsive expression of DREB2A. Coupling our transient expression analyses with yeast one-hybrid and chromatin immunoprecipitation (ChIP) assays indicated that the ABRE-BINDING PROTEIN 1 (AREB1), AREB2 and ABRE-BINDING FACTOR 3 (ABF3) bZIP transcription factors can bind to and activate the DREB2A promoter in an ABRE-dependent manner. Exogenous ABA application induced only a modest accumulation of the DREB2A transcript when compared with the osmotic stress treatment. However, the osmotic stress-induced DREB2A expression was found to be markedly impaired in several ABA-deficient and ABA-insensitive mutants. These results suggest that in addition to an ABA-independent pathway, the ABA-dependent pathway plays a positive role in the osmotic stress-responsive expression of DREB2A.

Soybean DREB1/CBF-type transcription factors function in heat and drought as well as cold stress-responsive gene expression.

PubMed

Kidokoro, Satoshi; Watanabe, Keitaro; Ohori, Teppei; Moriwaki, Takashi; Maruyama, Kyonoshin; Mizoi, Junya; Myint Phyu Sin Htwe, Nang; Fujita, Yasunari; Sekita, Sachiko; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2015-02-01

Soybean (Glycine max) is a globally important crop, and its growth and yield are severely reduced by abiotic stresses, such as drought, heat, and cold. The cis-acting element DRE (dehydration-responsive element)/CRT plays an important role in activating gene expression in response to these stresses. The Arabidopsis DREB1/CBF genes that encode DRE-binding proteins function as transcriptional activators in the cold stress responsive gene expression. In this study, we identified 14 DREB1-type transcription factors (GmDREB1s) from a soybean genome database. The expression of most GmDREB1 genes in soybean was strongly induced by a variety of abiotic stresses, such as cold, drought, high salt, and heat. The GmDREB1 proteins activated transcription via DREs (dehydration-responsive element) in Arabidopsis and soybean protoplasts. Transcriptome analyses using transgenic Arabidopsis plants overexpressing GmDREB1s indicated that many of the downstream genes are cold-inducible and overlap with those of Arabidopsis DREB1A. We then comprehensively analyzed the downstream genes of GmDREB1B;1, which is closely related to DREB1A, using a transient expression system in soybean protoplasts. The expression of numerous genes induced by various abiotic stresses were increased by overexpressing GmDREB1B;1 in soybean, and DREs were the most conserved element in the promoters of these genes. The downstream genes of GmDREB1B;1 included numerous soybean-specific stress-inducible genes that encode an ABA receptor family protein, GmPYL21, and translation-related genes, such as ribosomal proteins. We confirmed that GmDREB1B;1 directly activates GmPYL21 expression and enhances ABRE-mediated gene expression in an ABA-independent manner. These results suggest that GmDREB1 proteins activate the expression of numerous soybean-specific stress-responsive genes under diverse abiotic stress conditions. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Identification of the G13 (cAMP-response-element-binding protein-related protein) gene product related to activating transcription factor 6 as a transcriptional activator of the mammalian unfolded protein response.

PubMed

Haze, K; Okada, T; Yoshida, H; Yanagi, H; Yura, T; Negishi, M; Mori, K

2001-04-01

Eukaryotic cells control the levels of molecular chaperones and folding enzymes in the endoplasmic reticulum (ER) by a transcriptional induction process termed the unfolded protein response (UPR). The mammalian UPR is mediated by the cis-acting ER stress response element consisting of 19 nt (CCAATN(9)CCACG), the CCACG part of which is considered to provide specificity. We recently identified the basic leucine zipper (bZIP) protein ATF6 as a mammalian UPR-specific transcription factor; ATF6 is activated by ER stress-induced proteolysis and binds directly to CCACG. Here we report that eukaryotic cells express another bZIP protein closely related to ATF6 in both structure and function. This protein encoded by the G13 (cAMP response element binding protein-related protein) gene is constitutively synthesized as a type II transmembrane glycoprotein anchored in the ER membrane and processed into a soluble form upon ER stress as occurs with ATF6. The proteolytic processing of ATF6 and the G13 gene product is accompanied by their relocation from the ER to the nucleus; their basic regions seem to function as a nuclear localization signal. Overexpression of the soluble form of the G13 product constitutively activates the UPR, whereas overexpression of a mutant lacking the activation domain exhibits a strong dominant-negative effect. Furthermore, the soluble forms of ATF6 and the G13 gene product are unable to bind to several point mutants of the cis-acting ER stress response element in vitro that hardly respond to ER stress in vivo. We thus concluded that the two related bZIP proteins are crucial transcriptional regulators of the mammalian UPR, and propose calling the ATF6 gene product ATF6alpha and the G13 gene product ATF6beta.

A meta-model analysis of a finite element simulation for defining poroelastic properties of intervertebral discs.

PubMed

Nikkhoo, Mohammad; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2013-06-01

Finite element analysis is an effective tool to evaluate the material properties of living tissue. For an interactive optimization procedure, the finite element analysis usually needs many simulations to reach a reasonable solution. The meta-model analysis of finite element simulation can be used to reduce the computation of a structure with complex geometry or a material with composite constitutive equations. The intervertebral disc is a complex, heterogeneous, and hydrated porous structure. A poroelastic finite element model can be used to observe the fluid transferring, pressure deviation, and other properties within the disc. Defining reasonable poroelastic material properties of the anulus fibrosus and nucleus pulposus is critical for the quality of the simulation. We developed a material property updating protocol, which is basically a fitting algorithm consisted of finite element simulations and a quadratic response surface regression. This protocol was used to find the material properties, such as the hydraulic permeability, elastic modulus, and Poisson's ratio, of intact and degenerated porcine discs. The results showed that the in vitro disc experimental deformations were well fitted with limited finite element simulations and a quadratic response surface regression. The comparison of material properties of intact and degenerated discs showed that the hydraulic permeability significantly decreased but Poisson's ratio significantly increased for the degenerated discs. This study shows that the developed protocol is efficient and effective in defining material properties of a complex structure such as the intervertebral disc.

Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore Emiliania huxleyi

NASA Astrophysics Data System (ADS)

Feng, Yuanyuan; Roleda, Michael Y.; Armstrong, Evelyn; Law, Cliff S.; Boyd, Philip W.; Hurd, Catriona L.

2018-01-01

A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2)) on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose-response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semi-quantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes.

ETHYLENE RESPONSE FACTOR 96 positively regulates Arabidopsis resistance to necrotrophic pathogens by direct binding to GCC elements of jasmonate - and ethylene-responsive defence genes.

PubMed

Catinot, Jérémy; Huang, Jing-Bo; Huang, Pin-Yao; Tseng, Min-Yuan; Chen, Ying-Lan; Gu, Shin-Yuan; Lo, Wan-Sheng; Wang, Long-Chi; Chen, Yet-Ran; Zimmerli, Laurent

2015-12-01

The ERF (ethylene responsive factor) family is composed of transcription factors (TFs) that are critical for appropriate Arabidopsis thaliana responses to biotic and abiotic stresses. Here we identified and characterized a member of the ERF TF group IX, namely ERF96, that when overexpressed enhances Arabidopsis resistance to necrotrophic pathogens such as the fungus Botrytis cinerea and the bacterium Pectobacterium carotovorum. ERF96 is jasmonate (JA) and ethylene (ET) responsive and ERF96 transcripts accumulation was abolished in JA-insensitive coi1-16 and in ET-insensitive ein2-1 mutants. Protoplast transactivation and electrophoresis mobility shift analyses revealed that ERF96 is an activator of transcription that binds to GCC elements. In addition, ERF96 mainly localized to the nucleus. Microarray analysis coupled to chromatin immunoprecipitation-PCR of Arabidopsis overexpressing ERF96 revealed that ERF96 enhances the expression of the JA/ET defence genes PDF1.2a, PR-3 and PR-4 as well as the TF ORA59 by direct binding to GCC elements present in their promoters. While ERF96-RNAi plants demonstrated wild-type resistance to necrotrophic pathogens, basal PDF1.2 expression levels were reduced in ERF96-silenced plants. This work revealed ERF96 as a key player of the ERF network that positively regulates the Arabidopsis resistance response to necrotrophic pathogens. © 2015 John Wiley & Sons Ltd.

Moving through the Stressed Genome: Emerging Regulatory Roles for Transposons in Plant Stress Response.

PubMed

Negi, Pooja; Rai, Archana N; Suprasanna, Penna

2016-01-01

The recognition of a positive correlation between organism genome size with its transposable element (TE) content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock's original 'Controlling Element' hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences, which project TEs as "distributed genomic control modules." According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution, and function and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement.

A novel role for CRTC2 in hepatic cholesterol synthesis through SREBP‐2

PubMed Central

Li, Yujie; Song, Yongfeng; Zhao, Meng; Guo, Yanjing; Yu, Chunxiao; Chen, Wenbin; Shao, Shanshan; Xu, Chao; Zhou, Xinli; Zhao, Lifang; Zhang, Zhenhai; Bo, Tao; Xia, Yu; Proud, Christopher G.; Wang, Xuemin; Wang, Li; Zhao, Jiajun

2017-01-01

Cholesterol synthesis is regulated by the transcription factor sterol regulatory element binding protein 2 (SREBP‐2) and its target gene 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase (HMGCR), which is the rate‐limiting enzyme in cholesterol synthesis. Cyclic adenosine monophosphate–responsive element (CRE) binding protein–regulated transcription coactivator (CRTC) 2 is the master regulator of glucose metabolism. However, the effect of CRTC2 on cholesterol and its potential molecular mechanism remain unclear. Here, we demonstrated that CRTC2 expression and liver cholesterol content were increased in patients with high serum cholesterol levels who underwent resection of liver hemangiomas, as well as in mice fed a 4% cholesterol diet. Mice with adenovirus‐mediated CRTC2 overexpression also showed elevated lipid levels in both serum and liver tissues. Intriguingly, hepatic de novo cholesterol synthesis was markedly increased under these conditions. In contrast, CRTC2 ablation in mice fed a 4% cholesterol diet (18 weeks) showed decreased lipid levels in serum and liver tissues compared with those in littermate wild‐type mice. The expression of lipogenic genes (SREBP‐2 and HMGCR) was consistent with hepatic CRTC2 levels. In vivo imaging showed enhanced adenovirus‐mediated HMGCR‐luciferase activity in adenovirus‐mediated CRTC2 mouse livers; however, the activity was attenuated after mutation of CRE or sterol regulatory element sequences in the HMGCR reporter construct. The effect of CRTC2 on HMGCR in mouse livers was alleviated upon SREBP‐2 knockdown. CRTC2 modulated SREBP‐2 transcription by CRE binding protein, which recognizes the half‐site CRE sequence in the SREBP‐2 promoter. CRTC2 reduced the nuclear protein expression of forkhead box O1 and subsequently increased SREBP‐2 transcription by binding insulin response element 1, rather than insulin response element 2, in the SREBP‐2 promoter. Conclusion: CRTC2 regulates the transcription of SREBP‐2 by interfering with the recognition of insulin response element 1 in the SREBP‐2 promoter by forkhead box O1, thus inducing SREBP‐2/HMGCR signaling and subsequently facilitating hepatic cholesterol synthesis. (Hepatology 2017;66:481–497). PMID:28395113

Optical sensing elements for nitrogen dioxide (NO.sub.2) gas detection, a sol-gel method for making the sensing elements and fiber optic sensors incorporating nitrogen dioxide gas optical sensing elements

DOEpatents

Mechery, Shelly John [Mississippi State, MS; Singh, Jagdish P [Starkville, MS

2007-07-03

A sensing element, a method of making a sensing element, and a fiber optic sensor incorporating the sensing element are described. The sensor can be used for the quantitative detection of NO.sub.2 in a mixture of gases. The sensing element can be made by incorporating a diazotizing reagent which reacts with nitrous ions to produce a diazo compound and a coupling reagent which couples with the diazo compound to produce an azo dye into a sol and allowing the sol to form an optically transparent gel. The sensing element changes color in the presence of NO.sub.2 gas. The temporal response of the absorption spectrum at various NO.sub.2 concentrations has also been recorded and analyzed. Sensors having different design configurations are described. The sensing element can detect NO.sub.2 gas at levels of parts per billion.

Alterations in early cytokine-mediated immune responses to Plasmodium falciparum infection in Tanzanian children with mineral element deficiencies: a cross-sectional survey

PubMed Central

2010-01-01

Background Deficiencies in vitamins and mineral elements are important causes of morbidity in developing countries, possibly because they lead to defective immune responses to infection. The aim of the study was to assess the effects of mineral element deficiencies on early innate cytokine responses to Plasmodium falciparum malaria. Methods Peripheral blood mononuclear cells from 304 Tanzanian children aged 6-72 months were stimulated with P. falciparum-parasitized erythrocytes obtained from in vitro cultures. Results The results showed a significant increase by 74% in geometric mean of TNF production in malaria-infected individuals with zinc deficiency (11% to 240%; 95% CI). Iron deficiency anaemia was associated with increased TNF production in infected individuals and overall with increased IL-10 production, while magnesium deficiency induced increased production of IL-10 by 46% (13% to 144%) in uninfected donors. All donors showed a response towards IL-1β production, drawing special attention for its possible protective role in early innate immune responses to malaria. Conclusions In view of these results, the findings show plasticity in cytokine profiles of mononuclear cells reacting to malaria infection under conditions of different micronutrient deficiencies. These findings lay the foundations for future inclusion of a combination of precisely selected set of micronutrients rather than single nutrients as part of malaria vaccine intervention programmes in endemic countries. PMID:20470442

Expression analysis and functional characterization of a novel cold-responsive gene CbCOR15a from Capsella bursa-pastoris.

PubMed

Zhou, Mingqi; Wu, Lihua; Liang, Jing; Shen, Chen; Lin, Juan

2012-05-01

The cold-responsive (COR) genes involved in C-repeat binding factor signaling pathway function essentially in cold acclimation of higher plants. A novel COR gene CbCOR15a from shepherd's purse (Capsella bursa-pastoris) was predicted to be a homolog of COR15 in Arabidopsis. The analysis of tissue specific expression pattern as well as characterization of the CbCOR15a promoter revealed that the expression of CbCOR15a was induced by coldness not only in leaves and stem but also in roots. Sequence analysis showed that a 909 bp promoter region of CbCOR15a contained two CRT/DRE elements, two ABRE elements, one auxin-responsive TGA-element and one MeJA-responsive CGTCA-motif. In young seedlings the expression of CbCOR15a could be apparently increased by SA, ABA, MeJA and IAA, and transiently increased by GA(3) accompanied by obvious feedback suppression. According to the altered physiological index values in tobacco under cold treatments, the overexpression of CbCOR15a significantly increased the cold tolerance of transgenic tobacco plants. It can be suggested that CbCOR15a was involved in cold response of Capsella bursa-pastoris associated with SA, ABA, MeJA, IAA and GA(3) regulation and confers enhanced cold acclimation in transgenic plants.

KAOS/LIB-V: A library of nuclear response functions generated by KAOS-V code from ENDF/B-V and other data files

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

Farawila, Y.; Gohar, Y.; Maynard, C.

1989-04-01

KAOS/LIB-V: A library of processed nuclear responses for neutronics analyses of nuclear systems has been generated. The library was prepared using the KAOS-V code and nuclear data from ENDF/B-V. The library includes kerma (kinetic energy released in materials) factors and other nuclear response functions for all materials presently of interest in fusion and fission applications for 43 nonfissionable and 15 fissionable isotopes and elements. The nuclear response functions include gas production and tritium-breeding functions, and all important reaction cross sections. KAOS/LIB-V employs the VITAMIN-E weighting function and energy group structure of 174 neutron groups. Auxiliary nuclear data bases, e.g., themore » Japanese evaluated nuclear data library JENDL-2 were used as a source of isotopic cross sections when these data are not provided in ENDF/B-V files for a natural element. These are needed mainly to estimate average quantities such as effective Q-values for the natural element. This analysis of local energy deposition was instrumental in detecting and understanding energy balance deficiencies and other problems in the ENDF/B-V data. Pertinent information about the library and a graphical display of the main nuclear response functions for all materials in the library are given. 35 refs.« less

The response to September 11: a disaster case study.

PubMed

Crane, Michael A; Levy-Carrick, Nomi C; Crowley, Laura; Barnhart, Stephanie; Dudas, Melissa; Onuoha, Uchechukwu; Globina, Yelena; Haile, Winta; Shukla, Gauri; Ozbay, Fatih

2014-01-01

The response to 9/11 continues into its 14th year. The World Trade Center Health Program (WTCHP), a long-term monitoring and treatment program now funded by the Zadroga Act of 2010, includes >60,000 World Trade Center (WTC) disaster responders and community members ("survivors"). The aim of this review is to identify several elements that have had a critical impact on the evolution of the WTC response and, directly or indirectly, the health of the WTC-exposed population. It further explores post-disaster monitoring efforts, recent scientific findings from the WTCHP, and some implications of this experience for ongoing and future environmental disaster response. Transparency and responsiveness, site safety and worker training, assessment of acute and chronic exposure, and development of clinical expertise are interconnected elements determining efficacy of disaster response. Even in a relatively well-resourced environment, challenges regarding allocation of appropriate attention to vulnerable populations and integration of treatment response to significant medical and mental health comorbidities remain areas of ongoing programmatic development. Copyright © 2014 Icahn School of Medicine at Mount Sinai. All rights reserved.

Equipment-Device Task Commonality Analysis and Transfer of Training.

ERIC Educational Resources Information Center

Caro, Paul W.

Procedures were developed to enable training personnel systematically and objectively to determine the potential utility of training devices for teaching how to perform missions in operational rotary wing aircraft. These procedures allow comparison of task stimulus and response elements with corresponding elements in synthetic training equipment.…

Dancers Exult at the Awakening

ERIC Educational Resources Information Center

Smith, W. Alan

2004-01-01

This article explores the art form of dance as a metaphor for the teaching of theology. Employing the work of Maria Harris, the author contends that there are seven elements of dance than can serve as metaphors for teachers of theology: preparation, rhythm, movement, expectancy, response, embodiment, and performance. Each dance element is…

Children's Responses to Literature: Views of Children and Teachers.

ERIC Educational Resources Information Center

Pascoe, Elaine; Gilchrist, Margaret

1987-01-01

Presents a study comparing the elements children report enjoying in a book and the elements teachers believe children enjoy. Concludes that a great discrepancy exists between the two groups, as children reported they liked books offering excitement, suspense, and action, while teachers believed children pay more attention to characters. (JC)

DYNALIST II : A Computer Program for Stability and Dynamic Response Analysis of Rail Vehicle Systems : Volume 3. Technical Report Addendum.

DOT National Transportation Integrated Search

1976-07-01

Several new capabilities have been added to the DYNALIST II computer program. These include: (1) a component matrix generator that operates as a 3-D finite element modeling program where elements consist of rigid bodies, flexural bodies, wheelsets, s...

Probabilistic finite elements for fatigue and fracture analysis

NASA Astrophysics Data System (ADS)

Belytschko, Ted; Liu, Wing Kam

Attenuation is focused on the development of Probabilistic Finite Element Method (PFEM), which combines the finite element method with statistics and reliability methods, and its application to linear, nonlinear structural mechanics problems and fracture mechanics problems. The computational tool based on the Stochastic Boundary Element Method is also given for the reliability analysis of a curvilinear fatigue crack growth. The existing PFEM's have been applied to solve for two types of problems: (1) determination of the response uncertainty in terms of the means, variance and correlation coefficients; and (2) determination the probability of failure associated with prescribed limit states.

Statistical Energy Analysis (SEA) and Energy Finite Element Analysis (EFEA) Predictions for a Floor-Equipped Composite Cylinder

NASA Technical Reports Server (NTRS)

Grosveld, Ferdinand W.; Schiller, Noah H.; Cabell, Randolph H.

2011-01-01

Comet Enflow is a commercially available, high frequency vibroacoustic analysis software founded on Energy Finite Element Analysis (EFEA) and Energy Boundary Element Analysis (EBEA). Energy Finite Element Analysis (EFEA) was validated on a floor-equipped composite cylinder by comparing EFEA vibroacoustic response predictions with Statistical Energy Analysis (SEA) and experimental results. Statistical Energy Analysis (SEA) predictions were made using the commercial software program VA One 2009 from ESI Group. The frequency region of interest for this study covers the one-third octave bands with center frequencies from 100 Hz to 4000 Hz.

Probabilistic finite elements for fatigue and fracture analysis

NASA Technical Reports Server (NTRS)

Belytschko, Ted; Liu, Wing Kam

1992-01-01

Attenuation is focused on the development of Probabilistic Finite Element Method (PFEM), which combines the finite element method with statistics and reliability methods, and its application to linear, nonlinear structural mechanics problems and fracture mechanics problems. The computational tool based on the Stochastic Boundary Element Method is also given for the reliability analysis of a curvilinear fatigue crack growth. The existing PFEM's have been applied to solve for two types of problems: (1) determination of the response uncertainty in terms of the means, variance and correlation coefficients; and (2) determination the probability of failure associated with prescribed limit states.

TPA can overcome the requirement for EIa and together act synergistically in stimulating expression of the adenovirus EIII promoter.

PubMed Central

Buckbinder, L; Miralles, V J; Reinberg, D

1989-01-01

We have examined the control of gene expression from the adenovirus early region III (Ad-EIII) promoter, which contains two previously defined elements, the AP1 and ATF sites. We found that the AP1 element is capable of mediating activation by the adenovirus immediate early (EIa) gene products. Consistent with studies demonstrating that the AP1 site mediates signal transduction in response to 12-O-tetradecanoylphorbol 13-acetate (TPA) we have shown that TPA can activate Ad-EIII expression and overcome the requirement for EIa. Together TPA and EIa elicited a synergistic response in expression from the Ad-EIII promoter during both transient expression assays and viral infections. This synergistic effect required the AP1 element. An EIII promoter construct, in which sequences upstream of the TATA box had been replaced with four AP1 sites, was responsive to TPA and EIa and in combination promoted the synergistic effect. The analysis of specific factors involved in transcription from the Ad-EIII indicated that proteins recognizing the ATF and AP1 sites were important in expression from this promoter in vitro. Purification of protein factors that specifically stimulated EIII expression resulted in the isolation of a set of factors of the AP1 family. Affinity purified AP1 recognized and activated transcription through both the AP1 and ATF elements. In addition, a protein fraction was identified with DNA binding activity specific for the ATF element. This fraction was dependent on the ATF site for transcriptional activity. Images PMID:2531661

Responses of infaunal populations to benthoscape structure and the potential importance of transition zones

USGS Publications Warehouse

Zajac, R.N.; Lewis, R.S.; Poppe, L.J.; Twichell, D.C.; Vozarik, J.; DiGiacomo-Cohen, M. L.

2003-01-01

Relationships between population abundance and seafloor landscape, or benthoscape, structure were examined for 16 infaunal taxa in eastern Long Island Sound. Based on analyses of a side-scan sonar mosaic, the 19.4-km2 study area was comprised of six distinct large-scale (> km2) benthoscape elements, with varying levels of mesoscale (km2-m2) and small-scale (2) physical and biological habitat heterogeneity. Transition zones among elements varied from ~50 to 200 m in width, comprised ~32% of the benthoscape, and added to overall benthoscape heterogeneity. Population abundances of nine taxa varied significantly among the large-scale elements. Most species were found at high abundances only in one benthoscape element, but three had several foci of elevated abundances. Analyses of population responses to habitat heterogeneity at different spatial scales indicated that abundances of eight taxa varied significantly among spatial scales, but the significant scales were mixed among these species. Relatively large residual variations suggest significant amounts of mesoscale spatial variation were unaccounted for, varying from ~1 km2 to several m2. Responses to transition zones were mixed as well. Abundances of nine taxa varied significantly among transition zones and interiors of benthoscape elements, most with elevated abundances in transition zones. Our results show that infaunal populations exhibit complex and spatially varying patterns of abundance in relation to benthoscape structure and suggest that mesoscale variation may be particularly critical in this regard. Also, transition zones among benthoscape features add considerably to this variation and may be ecological important areas in seafloor environments.

Physiological Perturbation Reveals Modularity of Eyespot Development in the Painted Lady Butterfly, Vanessa cardui

PubMed Central

Rhen, Turk; Simmons, Rebecca B.

2016-01-01

Butterfly eyespots are complex morphological traits that can vary in size, shape and color composition even on the same wing surface. Homology among eyespots suggests they share a common developmental basis and function as an integrated unit in response to selection. Despite strong evidence of genetic integration, eyespots can also exhibit modularity or plasticity, indicating an underlying flexibility in pattern development. The extent to which particular eyespots or eyespot color elements exhibit modularity or integration is poorly understood, particularly following exposure to novel conditions. We used perturbation experiments to explore phenotypic correlations among different eyespots and their color elements on the ventral hindwing of V. cardui. Specifically, we identified which eyespots and eyespot features are most sensitive to perturbation by heat shock and injection of heparin—a cold shock mimic. For both treatments, the two central eyespots (3 + 4) were most affected by the experimental perturbations, whereas the outer eyespot border was more resistant to modification than the interior color elements. Overall, the individual color elements displayed a similar response to heat shock across all eyespots, but varied in their response to each other. Graphical modeling also revealed that although eyespots differ morphologically, regulation of eyespot size and colored elements appear to be largely integrated across the wing. Patterns of integration, however, were disrupted following heat shock, revealing that the strength of integration varies across the wing and is strongest between the two central eyespots. These findings support previous observations that document coupling between eyespots 3 + 4 in other nymphalid butterflies. PMID:27560365

Physiological Perturbation Reveals Modularity of Eyespot Development in the Painted Lady Butterfly, Vanessa cardui.

PubMed

Connahs, Heidi; Rhen, Turk; Simmons, Rebecca B

2016-01-01

Butterfly eyespots are complex morphological traits that can vary in size, shape and color composition even on the same wing surface. Homology among eyespots suggests they share a common developmental basis and function as an integrated unit in response to selection. Despite strong evidence of genetic integration, eyespots can also exhibit modularity or plasticity, indicating an underlying flexibility in pattern development. The extent to which particular eyespots or eyespot color elements exhibit modularity or integration is poorly understood, particularly following exposure to novel conditions. We used perturbation experiments to explore phenotypic correlations among different eyespots and their color elements on the ventral hindwing of V. cardui. Specifically, we identified which eyespots and eyespot features are most sensitive to perturbation by heat shock and injection of heparin-a cold shock mimic. For both treatments, the two central eyespots (3 + 4) were most affected by the experimental perturbations, whereas the outer eyespot border was more resistant to modification than the interior color elements. Overall, the individual color elements displayed a similar response to heat shock across all eyespots, but varied in their response to each other. Graphical modeling also revealed that although eyespots differ morphologically, regulation of eyespot size and colored elements appear to be largely integrated across the wing. Patterns of integration, however, were disrupted following heat shock, revealing that the strength of integration varies across the wing and is strongest between the two central eyespots. These findings support previous observations that document coupling between eyespots 3 + 4 in other nymphalid butterflies.

Identification of conserved cis-elements and transcription factors required for sterol-regulated transcription of stearoyl-CoA desaturase 1 and 2.

PubMed

Tabor, D E; Kim, J B; Spiegelman, B M; Edwards, P A

1999-07-16

We previously identified stearoyl-CoA desaturase 2 (SCD2) as a new member of the family of genes that are transcriptionally regulated in response to changing levels of nuclear sterol regulatory element binding proteins (SREBPs) or adipocyte determination and differentiation factor 1 (ADD1). A novel sterol regulatory element (SRE) (5'-AGCAGATTGTG-3') identified in the proximal promoter of the mouse SCD2 gene is required for induction of SCD2 promoter-reporter genes in response to cellular sterol depletion (Tabor, D. E., Kim, J. B., Spiegelman, B. M., and Edwards, P. A. (1998) J. Biol. Chem. 273, 22052-22058). In this report, we demonstrate that this novel SRE is both present in the promoter of the SCD1 gene and is critical for the sterol-dependent transcription of SCD1 promoter-reporter genes. Two conserved cis elements (5'-CCAAT-3') lie 5 and 48 base pairs 3' of the novel SREs in the promoters of both the SCD1 and SCD2 murine genes. Mutation of either of these putative NF-Y binding sites attenuates the transcriptional activation of SCD1 or SCD2 promoter-reporter genes in response to cellular sterol deprivation. Induction of both reporter genes is also attenuated when cells are cotransfected with dominant-negative forms of either NF-Y or SREBP. In addition, we demonstrate that the induction of SCD1 and SCD2 mRNAs that occurs during the differentiation of 3T3-L1 preadipocytes to adipocytes is paralleled by an increase in the levels of ADD1/SREBP-1c and that the SCD1 and SCD2 mRNAs are induced to even higher levels in response to ectopic expression of ADD1/SREBP-1c. We conclude that transcription of both SCD1 and SCD2 genes is responsive to cellular sterol levels and to the levels of nuclear SREBP/ADD1 and that transcriptional induction requires three spatially conserved cis elements, that bind SREBP and NF-Y. Additional studies demonstrate that maximal transcriptional repression of SCD2 reporter genes in response to an exogenous polyunsaturated fatty acid is dependent upon the SRE and the adjacent CCAAT motif.

Structural and Acoustic Numerical Modeling of a Curved Composite Honeycomb Panel

NASA Technical Reports Server (NTRS)

Grosveld, Ferdinand W.; Buehrle, Ralph D.; Robinson, Jay H.

2001-01-01

The finite and boundary element modeling of the curved section of a composite honeycomb aircraft fuselage sidewall was validated for both structural response and acoustic radiation. The curved panel was modeled in the pre-processor MSC/PATRAN. Geometry models of the curved panel were constructed based on the physical dimensions of the test article. Material properties were obtained from the panel manufacturer. Finite element models were developed to predict the modal parameters for free and supported panel boundary conditions up to a frequency of 600 Hz. Free boundary conditions were simulated by providing soft foam support under the four comers of the panel or by suspending the panel from elastic bands. Supported boundary conditions were obtained by clamping the panel between plastic tubing seated in grooves along the perimeter of a stiff and heavy frame. The frame was installed in the transmission loss window of the Structural Acoustic Loads and Transmission (SALT) facility at NASA Langley Research Center. The structural response of the curved panel due to point force excitation was predicted using MSC/NASTRAN and the radiated sound was computed with COMET/Acoustics. The predictions were compared with the results from experimental modal surveys and forced response tests on the fuselage panel. The finite element models were refined and updated to provide optimum comparison with the measured modal data. Excellent agreement was obtained between the numerical and experimental modal data for the free as well as for the supported boundary conditions. Frequency response functions (FRF) were computed relating the input force excitation at one panel location to the surface acceleration response at five panel locations. Frequency response functions were measured at the same locations on the test specimen and were compared with the calculated FRF values. Good agreement was obtained for the real and imaginary parts of the transfer functions when modal participation was allowed up to 3000 Hz. The validated finite element model was used to predict the surface velocities due to the point force excitation. Good agreement was obtained between the spatial characteristics of the predicted and measured surface velocities. The measured velocity data were input into the acoustic boundary element code to compute the sound radiated by the panel. The predicted sound pressure levels in the far-field of the panel agreed well with the sound pressure levels measured at the same location.

Regulation of cyclic adenosine monophosphate response element binding protein on renin expression in kidney via complex cyclic adenosine monophosphate response element-binding-protein-binding protein/P300 recruitment.

PubMed

Li, Pei; Zhang, Jing; Zhu, Yuanfang; Liu, Ming; Xuan, Jin

2015-11-01

Renin synthesis and release is the rate-limiting step in the renin-angiotensin system, because cyclic adenosine monophosphate (cAMP) has been identified as dominant pathway for renin gene expression, and cAMP response element-binding protein (CREB) is found in the human and mouse renin promoter. This study aimed to evaluate the role of CREB in expression of the renin gene. We created conditional deletion of CREB in mice with low-sodium diet, specifically in renin cells of the kidney. To assess the effect of CREB on renin expression, immunostaining of renin was used in samples from wild-type mice and mice with gene knock-down of CREB. Cyclic AMP response element-binding-protein-binding protein (CBP) and p300 were measured in cultured renin cells of the mice, and RNA detection was done with real-time polymerase chain reaction. With low-sodium diet, renin was expressed along the whole wall of the afferent glomerular arterioles in wild-type mice, while there was no increase or even decrease in renin expression in CREB-specific deletion mice; RNA level of renin in cultured cells decreased by 50% with single knock-down of CREB, CBP, or p300, and decreased 70% with triple knock-down of CREB, CBP, and p300. This study found that CREB was important for renin synthesis and the role of CREB can be achieved through the recruitment of co-activators CBP and p300.

Characterization of a hypoxia-response element in the Epo locus of the pufferfish, Takifugu rubripes.

PubMed

Kulkarni, Rashmi P; Tohari, Sumanty; Ho, Adrian; Brenner, Sydney; Venkatesh, Byrappa

2010-06-01

Animals respond to hypoxia by increasing synthesis of the glycoprotein hormone erythropoietin (Epo) which in turn stimulates the production of red blood cells. The gene encoding Epo has been recently cloned in teleost fishes such as the pufferfish Takifugu rubripes (fugu) and zebrafish (Danio rerio). It has been shown that the transcription levels of Epo in teleost fishes increase in response to anemia or hypoxia in a manner similar to its human ortholog. However, the cis-regulatory element(s) mediating the hypoxia response of Epo gene in fishes has not been identified. In the present study, using the human hepatoma cell line (Hep3B), we have identified and characterized a hypoxia response element (HRE) in the fugu Epo locus. The sequence of the fugu HRE (ACGTGCTG) is identical to that of the HRE in the human EPO locus. However, unlike the HRE in the mammalian Epo locus, which is located in the 3' region of the gene, the fugu HRE is located in the 5' flanking region and on the opposite strand of DNA. This HRE is conserved in other teleosts such as Tetraodon and zebrafish in a similar location. A 365-bp fragment containing the fugu HRE was able to drive GFP expression in the liver of transgenic zebrafish. However, we could not ascertain if the expression of transgene is induced by hypoxia in vivo due to the low and variable levels of GFP expression in transgenic zebrafish. Our investigations also revealed that the Epo locus has experienced extensive rearrangements during vertebrate evolution. Copyright © 2010 Elsevier B.V. All rights reserved.

Aldosterone alters the chromatin structure of the murine endothelin-1 gene.

PubMed

Welch, Amanda K; Jeanette Lynch, I; Gumz, Michelle L; Cain, Brian D; Wingo, Charles S

2016-08-15

Aldosterone increases sodium reabsorption in the renal collecting duct and systemic blood pressure. Paradoxically, aldosterone also induces transcription of the endothelin-1 (Edn1) gene to increase protein (ET-1) levels, which inhibits sodium reabsorption. Here we investigated changes in the chromatin structure of the Edn1 gene of collecting duct cell lines in response to aldosterone treatment. The Edn1 gene has a CpG island that encompasses the transcription start site and four sites in the 5' regulatory region previously linked to transcriptional regulation. The chromatin structure of the Edn1 gene was investigated using a quantitative PCR-based DNaseI hypersensitivity assay in murine hepatocyte (AML12), renal cortical collecting duct (mpkCCDC14), outer medullary collecting duct1 (OMCD1), and inner medullary collecting duct-3 (IMCD-3) cell lines. The CpG island was uniformly accessible. One calcium-responsive NFAT element remained at low chromatin accessibility in all cell lines under all conditions tested. However, the second calcium responsive NFAT element located at -1563bp upstream became markedly more accessible in IMCD-3 cells exposed to aldosterone. Importantly, one established aldosterone hormone response element HRE at -671bp relative to the transcription start site was highly accessible, and another HRE (-551bp) became more accessible in aldosterone-treated IMCD-3 and OMCD1 cells. The evidence supports a model in which aldosterone activation of the mineralocorticoid receptor (MR) results in the MR-hormone complex binding at HRE at -671bp to open chromatin structure around other regulatory elements in the Edn1 gene. Published by Elsevier Inc.

The expression pattern of the Picea glauca Defensin 1 promoter is maintained in Arabidopsis thaliana, indicating the conservation of signalling pathways between angiosperms and gymnosperms.

PubMed

Germain, Hugo; Lachance, Denis; Pelletier, Gervais; Fossdal, Carl Gunnar; Solheim, Halvor; Séguin, Armand

2012-01-01

A 1149 bp genomic fragment corresponding to the 5' non-coding region of the PgD1 (Picea glauca Defensin 1) gene was cloned, characterized, and compared with all Arabidopsis thaliana defensin promoters. The cloned fragment was found to contain several motifs specific to defence or hormonal response, including a motif involved in the methyl jasmonate reponse, a fungal elicitor responsive element, and TC-rich repeat cis-acting element involved in defence and stress responsiveness. A functional analysis of the PgD1 promoter was performed using the uidA (GUS) reporter system in stably transformed Arabidopsis and white spruce plants. The PgD1 promoter was responsive to jasmonic acid (JA), to infection by fungus and to wounding. In transgenic spruce embryos, GUS staining was clearly restricted to the shoot apical meristem. In Arabidopsis, faint GUS coloration was observed in leaves and flowers and a strong blue colour was observed in guard cells and trichomes. Transgenic Arabidopsis plants expressing the PgD1::GUS construct were also infiltrated with the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000. It caused a suppression of defensin expression probably resulting from the antagonistic relationship between the pathogen-stimulated salicylic acid pathway and the jasmonic acid pathway. It is therefore concluded that the PgD1 promoter fragment cloned appears to contain most if not all the elements for proper PgD1 expression and that these elements are also recognized in Arabidopsis despite the phylogenetic and evolutionary differences that separates them.

Functional architecture of Escherichia coli: new insights provided by a natural decomposition approach.

PubMed

Freyre-González, Julio A; Alonso-Pavón, José A; Treviño-Quintanilla, Luis G; Collado-Vides, Julio

2008-10-27

Previous studies have used different methods in an effort to extract the modular organization of transcriptional regulatory networks. However, these approaches are not natural, as they try to cluster strongly connected genes into a module or locate known pleiotropic transcription factors in lower hierarchical layers. Here, we unravel the transcriptional regulatory network of Escherichia coli by separating it into its key elements, thus revealing its natural organization. We also present a mathematical criterion, based on the topological features of the transcriptional regulatory network, to classify the network elements into one of two possible classes: hierarchical or modular genes. We found that modular genes are clustered into physiologically correlated groups validated by a statistical analysis of the enrichment of the functional classes. Hierarchical genes encode transcription factors responsible for coordinating module responses based on general interest signals. Hierarchical elements correlate highly with the previously studied global regulators, suggesting that this could be the first mathematical method to identify global regulators. We identified a new element in transcriptional regulatory networks never described before: intermodular genes. These are structural genes that integrate, at the promoter level, signals coming from different modules, and therefore from different physiological responses. Using the concept of pleiotropy, we have reconstructed the hierarchy of the network and discuss the role of feedforward motifs in shaping the hierarchical backbone of the transcriptional regulatory network. This study sheds new light on the design principles underpinning the organization of transcriptional regulatory networks, showing a novel nonpyramidal architecture composed of independent modules globally governed by hierarchical transcription factors, whose responses are integrated by intermodular genes.

Electrostatically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Thundat, Thomas G.; Wachter, Eric A.; Davis, J. Kenneth

2001-01-01

Methods and apparatus for detecting particular frequencies of acoustic vibration utilize an electrostatically-tunable beam element having a stress-sensitive coating and means for providing electrostatic force to controllably deflect the beam element thereby changing its stiffness and its resonance frequency. It is then determined from the response of the electrostatically-tunable beam element to the acoustical vibration to which the beam is exposed whether or not a particular frequency or frequencies of acoustic vibration are detected.

Magnetically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Davis, J. Kenneth; Thundat, Thomas G.; Wachter, Eric A.

2001-01-01

Methods and apparatus for detecting particular frequencies of vibration utilize a magnetically-tunable beam element having a stress-sensitive coating and means for providing magnetic force to controllably deflect the beam element thereby changing its stiffness and its resonance frequency. It is then determined from the response of the magnetically-tunable beam element to the vibration to which the beam is exposed whether or not a particular frequency or frequencies of vibration are detected.

Preparation and Launch of the JEM ISS Elements - A NASA Mission Manager's Perspective

NASA Technical Reports Server (NTRS)

Higginbotham, Scott A.

2016-01-01

The pre-flight launch site preparations and launch of the Japanese Experiment Module (JEM) elements of the International Space Station required an intense multi-year, international collaborative effort between US and Japanese personnel at the Kennedy Space Center (KSC). This presentation will provide a brief overview of KSC, a brief overview of the ISS, and a summary of authors experience managing the NASA team responsible that supported and conducted the JEM element operations.

Bianisotropic metamaterial

DOEpatents

El-Kady, Ihab F.; Reinke, Charles M.

2017-07-18

The topology of the elements of a metamaterial can be engineered from its desired electromagnetic constitutive tensor using an inverse group theory method. Therefore, given a desired electromagnetic response and a generic metamaterial elemental design, group theory is applied to predict the various ways that the element can be arranged in three dimensions to produce the desired functionality. An optimizer can then be applied to an electromagnetic modeling tool to fine tune the values of the electromagnetic properties of the resulting metamaterial topology.

Rotor-to-stator Partial Rubbing and Its Effects on Rotor Dynamic Response

NASA Technical Reports Server (NTRS)

Muszynska, Agnes; Franklin, Wesley D.; Hayashida, Robert D.

1991-01-01

Results from experimental and analytical studies on rotor to stationary element partial rubbings at several locations and their effects on rotor dynamic responses are presented. The mathematical model of a rubbing rotor is given. The computer program provides numerical results which agree with experimentally obtained rotor responses.

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

NASA Technical Reports Server (NTRS)

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

1996-01-01

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

A directional microphone array for acoustic studies of wind tunnel models

NASA Technical Reports Server (NTRS)

Soderman, P. T.; Noble, S. C.

1974-01-01

An end-fire microphone array that utilizes a digital time delay system has been designed and evaluated for measuring noise in wind tunnels. The directional response of both a four- and eight-element linear array of microphones has enabled substantial rejection of background noise and reverberations in the NASA Ames 40- by 80-foot wind tunnel. In addition, it is estimated that four- and eight-element arrays reject 6 and 9 dB, respectively, of microphone wind noise, as compared with a conventional omnidirectional microphone with nose cone. Array response to two types of jet engine models in the wind tunnel is presented. Comparisons of array response to loudspeakers in the wind tunnel and in free field are made.

Effects of rare earth elements and REE-binding proteins on physiological responses in plants.

PubMed

Liu, Dongwu; Wang, Xue; Chen, Zhiwei

2012-02-01

Rare earth elements (REEs), which include 17 elements in the periodic table, share chemical properties related to a similar external electronic configuration. REEs enriched fertilizers have been used in China since the 1980s. REEs could enter the cell and cell organelles, influence plant growth, and mainly be bound with the biological macromolecules. REE-binding proteins have been found in some plants. In addition, the chlorophyll activities and photosynthetic rate can be regulated by REEs. REEs could promote the protective function of cell membrane and enhance the plant resistance capability to stress produced by environmental factors, and affect the plant physiological mechanism by regulating the Ca²⁺ level in the plant cells. The focus of present review is to describe how REEs and REE-binding proteins participate in the physiological responses in plants.

Inverted repeat Alu elements in the human lincRNA-p21 adopt a conserved secondary structure that regulates RNA function

PubMed Central

Chillón, Isabel; Pyle, Anna M.

2016-01-01

LincRNA-p21 is a long intergenic non-coding RNA (lincRNA) involved in the p53-mediated stress response. We sequenced the human lincRNA-p21 (hLincRNA-p21) and found that it has a single exon that includes inverted repeat Alu elements (IRAlus). Sense and antisense Alu elements fold independently of one another into a secondary structure that is conserved in lincRNA-p21 among primates. Moreover, the structures formed by IRAlus are involved in the localization of hLincRNA-p21 in the nucleus, where hLincRNA-p21 colocalizes with paraspeckles. Our results underscore the importance of IRAlus structures for the function of hLincRNA-p21 during the stress response. PMID:27378782

Measuring the photodetector frequency response for ultrasonic applications by a heterodyne system with difference- frequency servo control.

PubMed

Koch, Christian

2010-05-01

A technique for the calibration of photodiodes in ultrasonic measurement systems using standard and cost-effective optical and electronic components is presented. A heterodyne system was realized using two commercially available distributed feedback lasers, and the required frequency stability and resolution were ensured by a difference-frequency servo control scheme. The frequency-sensitive element generating the error signal for the servo loop comprised a delay-line discriminator constructed from electronic elements. Measurements were carried out at up to 450 MHz, and the uncertainties of about 5% (k = 2) can be further reduced by improved radio frequency power measurement without losing the feature of using only simple elements. The technique initially dedicated to the determination of the frequency response of photodetectors applied in ultrasonic applications can be transferred to other application fields of optical measurements.

An Ethics of Permission: A Response to the California End of Life Option Act.

PubMed

Nelson, Craig

2016-01-01

An ethics of permission can be helpful in framing a response to the ethical differences surrounding the California End of Life Option Act. Law does not define morality, and reaching a moral understanding demands thorough reflection. An ethics of permission examines the ethical demands of a permissive law for both clinician and patient. Serving the good of the patient, respecting professional conscience, and following the law are three ethical elements. Although developing an ethics of permission includes these three elements, these elements do not exhaust all the moral implications involved. An ethics of permission also includes the importance of exercising professional tolerance in the honoring of clinicians who choose to participate or refuse to participate. In addition, an ethics of permission also provides insight in implementing just and fair behavior among medical professionals.

E2-mediated cathepsin D (CTSD) activation involves looping of distal enhancer elements.

PubMed

Bretschneider, Nancy; Kangaspeska, Sara; Seifert, Martin; Reid, George; Gannon, Frank; Denger, Stefanie

2008-08-01

Estrogen receptor alpha (ERalpha) is a ligand dependent transcription factor that regulates the expression of target genes through interacting with cis-acting estrogen response elements (EREs). However, only a minority of ERalpha binding sites are located within the proximal promoter regions of responsive genes. Here we report the characterization of an ERE located 9kbp upstream of the TSS of the cathepsin D gene (CTSD) that up-regulates CTSD expression upon estrogen stimulation in MCF-7 cells. Using ChIP, we show recruitment of ERalpha and phosphorylated PolII at the CTSD distal enhancer region. Moreover, we determine the kinetics of transient CpG methylation on the promoter region of CTSD and for the first time, at a distal enhancer element. We show that ERalpha is crucial for long-distance regulation of CTSD expression involving a looping mechanism.

Modular assembly of optical nanocircuits.

PubMed

Shi, Jinwei; Monticone, Francesco; Elias, Sarah; Wu, Yanwen; Ratchford, Daniel; Li, Xiaoqin; Alù, Andrea

2014-05-29

A key element enabling the microelectronic technology advances of the past decades has been the conceptualization of complex circuits with versatile functionalities as being composed of the proper combination of basic 'lumped' circuit elements (for example, inductors and capacitors). In contrast, modern nanophotonic systems are still far from a similar level of sophistication, partially because of the lack of modularization of their response in terms of basic building blocks. Here we demonstrate the design, assembly and characterization of relatively complex photonic nanocircuits by accurately positioning a number of metallic and dielectric nanoparticles acting as modular lumped elements. The nanoparticle clusters produce the desired spectral response described by simple circuit rules and are shown to be dynamically reconfigurable by modifying the direction or polarization of impinging signals. Our work represents an important step towards extending the powerful modular design tools of electronic circuits into nanophotonic systems.

Modular assembly of optical nanocircuits

NASA Astrophysics Data System (ADS)

Shi, Jinwei; Monticone, Francesco; Elias, Sarah; Wu, Yanwen; Ratchford, Daniel; Li, Xiaoqin; Alù, Andrea

2014-05-01

A key element enabling the microelectronic technology advances of the past decades has been the conceptualization of complex circuits with versatile functionalities as being composed of the proper combination of basic ‘lumped’ circuit elements (for example, inductors and capacitors). In contrast, modern nanophotonic systems are still far from a similar level of sophistication, partially because of the lack of modularization of their response in terms of basic building blocks. Here we demonstrate the design, assembly and characterization of relatively complex photonic nanocircuits by accurately positioning a number of metallic and dielectric nanoparticles acting as modular lumped elements. The nanoparticle clusters produce the desired spectral response described by simple circuit rules and are shown to be dynamically reconfigurable by modifying the direction or polarization of impinging signals. Our work represents an important step towards extending the powerful modular design tools of electronic circuits into nanophotonic systems.

An Ethics of Permission: A Response to the California End of Life Option Act

PubMed Central

Nelson, Craig

2016-01-01

An ethics of permission can be helpful in framing a response to the ethical differences surrounding the California End of Life Option Act. Law does not define morality, and reaching a moral understanding demands thorough reflection. An ethics of permission examines the ethical demands of a permissive law for both clinician and patient. Serving the good of the patient, respecting professional conscience, and following the law are three ethical elements. Although developing an ethics of permission includes these three elements, these elements do not exhaust all the moral implications involved. An ethics of permission also includes the importance of exercising professional tolerance in the honoring of clinicians who choose to participate or refuse to participate. In addition, an ethics of permission also provides insight in implementing just and fair behavior among medical professionals. PMID:27541320

Exact finite element method analysis of viscoelastic tapered structures to transient loads

NASA Technical Reports Server (NTRS)

Spyrakos, Constantine Chris

1987-01-01

A general method is presented for determining the dynamic torsional/axial response of linear structures composed of either tapered bars or shafts to transient excitations. The method consists of formulating and solving the dynamic problem in the Laplace transform domain by the finite element method and obtaining the response by a numerical inversion of the transformed solution. The derivation of the torsional and axial stiffness matrices is based on the exact solution of the transformed governing equation of motion, and it consequently leads to the exact solution of the problem. The solution permits treatment of the most practical cases of linear tapered bars and shafts, and employs modeling of structures with only one element per member which reduces the number of degrees of freedom involved. The effects of external viscous or internal viscoelastic damping are also taken into account.

Trace Elements in Calcifying Marine Invertebrates Indicate Diverse Sensitivities to the Seawater Carbonate System

NASA Astrophysics Data System (ADS)

Doss, W. C.

2015-12-01

Surface ocean absorption of anthropogenic CO2 emissions resulting in ocean acidification may interfere with the ability of calcifying marine organisms to biomineralize, since the drop in pH is accompanied by reductions in CaCO3 saturation state. However, recent experiments show that net calcification rates of cultured benthic invertebrate taxa exhibit diverse responses to pCO2-induced changes in saturation state (Ries et al., 2009). Advancement of geochemical tools as biomineralization indicators will enable us to better understand these results and therefore help predict the impacts of ongoing and future decrease in seawater pH on marine organisms. Here we build upon previous work on these specimens by measuring the elemental composition of biogenic calcite and aragonite precipitated in four pCO2 treatments (400; 600; 900; and 2850 ppm). Element ratios (including Sr/Ca, Mg/Ca, Li/Ca, B/Ca, U/Ca, Ba/Ca, Cd/Ca, and Zn/Ca) were analyzed in 18 macro-invertebrate species representing seven phyla (crustacea, cnidaria, echinoidea, rhodophyta, chlorophyta, gastropoda, bivalvia, annelida), then compared to growth rate data and experimental seawater carbonate system parameters: [CO32-], [HCO3-], pH, saturation state, and DIC. Correlations between calcite or aragonite composition and seawater carbonate chemistry are highly taxa-specific, but do not resemble trends observed in growth rate for all species. Apparent carbonate system sensitivities vary widely by element, ranging from strongly correlated to no significant response. Interpretation of these results is guided by mounting evidence for the capacity of individual species to modulate pH and/or saturation state at the site of calcification in response to ambient seawater chemistry. Such biomineralization pathways and strategies in turn likely influence elemental fractionation during CaCO3 precipitation. Ries, J.B., A.L. Cohen, A.L., and D.C. McCorkle (2009), Marine calcifiers exhibit mixed responses to CO2-induced ocean acidification, Geology, 37(12), 1131-1134.

Limitations of Current AHA Guidelines and Proposal of New Guidelines for the Preparticipation Examination of Athletes.

PubMed

Dunn, Tim P; Pickham, David; Aggarwal, Sonya; Saini, Divya; Kumar, Nikhil; Wheeler, Matthew T; Perez, Marco; Ashley, Euan; Froelicher, Victor F

2015-11-01

To examine the prevalence of athletes who screen positive with the preparticipation examination guidelines from the American Heart Association, the AHA 12-elements, in combination with 3 screening electrocardiogram (ECG) criteria. Observational cross-sectional study. Stanford University Sports Medicine Clinic. Total of 1596 participants, including 297 (167 male; mean age, 16.2 years) high school athletes, 1016 (541 male; mean age, 18.8 years) collegiate athletes, and 283 (mean age, 26.3 years) male professional athletes. Athletes were screened using the 8 personal and family history questions from the AHA 12-elements. Electrocardiograms were obtained for all participants and interpreted using Seattle criteria, Stanford criteria, and European Society of Cardiology (ESC) recommendations. Approximately one-quarter of all athletes (23.8%) had at least 1 positive response to the AHA personal and family history elements. High school and college athletes had similar rates of having at least 1 positive response (25.9% vs 27.4%), whereas professional athletes had a significantly lower rate of having at least 1 positive response (8.8%, P < 0.05). Females reported more episodes of unexplained syncope (11.4% vs 7.5%, P = 0.017) and excessive exertional dyspnea with exercise (11.1% vs 6.1%, P = 0.001) than males. High school athletes had more positive responses to the family history elements when compared with college athletes (P < 0.05). The percentage of athletes who had an abnormal ECG varied between Seattle criteria (6.0%), Stanford criteria (8.8%), and ESC recommendations (26.8%). Many athletes screen positive under current screening recommendations, and ECG results vary widely by interpretation criteria. In a patient population without any adverse cardiovascular events, the currently recommended AHA 12-elements have an unacceptably high rate of false positives. Newer screening guidelines are needed, with fewer false positives and evidence-based updates.

Mineral inversion for element capture spectroscopy logging based on optimization theory

NASA Astrophysics Data System (ADS)

Zhao, Jianpeng; Chen, Hui; Yin, Lu; Li, Ning

2017-12-01

Understanding the mineralogical composition of a formation is an essential key step in the petrophysical evaluation of petroleum reservoirs. Geochemical logging tools can provide quantitative measurements of a wide range of elements. In this paper, element capture spectroscopy (ECS) was taken as an example and an optimization method was adopted to solve the mineral inversion problem for ECS. This method used the converting relationship between elements and minerals as response equations and took into account the statistical uncertainty of the element measurements and established an optimization function for ECS. Objective function value and reconstructed elemental logs were used to check the robustness and reliability of the inversion method. Finally, the inversion mineral results had a good agreement with x-ray diffraction laboratory data. The accurate conversion of elemental dry weights to mineral dry weights formed the foundation for the subsequent applications based on ECS.

High temperature electrically conducting ceramic heating element and control system

NASA Technical Reports Server (NTRS)

Halbach, C. R.; Page, R. J.

1975-01-01

Improvements were made in both electrode technology and ceramic conductor quality to increase significantly the lifetime and thermal cycling capability of electrically conducting ceramic heater elements. These elements were operated in vacuum, inert and reducing environments as well as oxidizing atmospheres adding to the versatility of the conducting ceramic as an ohmic heater. Using stabilized zirconia conducting ceramic heater elements, a furnace was fabricated and demonstrated to have excellent thermal response and cycling capability. The furnace was used to melt platinum-20% rhodium alloy (melting point 1904 C) with an isothermal ceramic heating element having a nominal working cavity size of 2.5 cm diameter by 10.0 cm long. The furnace was operated to 1940 C with the isothermal ceramic heating element. The same furnace structure was fitted with a pair of main heater elements to provide axial gradient temperature control over a working cavity length of 17.8 cm.

Four-terminal circuit element with photonic core

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

Sampayan, Stephen

A four-terminal circuit element is described that includes a photonic core inside of the circuit element that uses a wide bandgap semiconductor material that exhibits photoconductivity and allows current flow through the material in response to the light that is incident on the wide bandgap material. The four-terminal circuit element can be configured based on various hardware structures using a single piece or multiple pieces or layers of a wide bandgap semiconductor material to achieve various designed electrical properties such as high switching voltages by using the photoconductive feature beyond the breakdown voltages of semiconductor devices or circuits operated basedmore » on electrical bias or control designs. The photonic core aspect of the four-terminal circuit element provides unique features that enable versatile circuit applications to either replace the semiconductor transistor-based circuit elements or semiconductor diode-based circuit elements.« less

Effective Simulation of Delamination in Aeronautical Structures Using Shells and Cohesive Elements

NASA Technical Reports Server (NTRS)

Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

2007-01-01

A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

Cohesive Elements for Shells

NASA Technical Reports Server (NTRS)

Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

2007-01-01

A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

Nonlinear analysis for the response and failure of compression-loaded angle-ply laminates with a hole

NASA Technical Reports Server (NTRS)

Mathison, Steven R.; Herakovich, Carl T.; Pindera, Marek-Jerzy; Shuart, Mark J.

1987-01-01

The objective was to determine the effect of nonlinear material behavior on the response and failure of unnotched and notched angle-ply laminates under uniaxial compressive loading. The endochronic theory was chosen as the constitutive theory to model the AS4/3502 graphite-epoxy material system. Three-dimensional finite element analysis incorporating the endochronic theory was used to determine the stresses and strains in the laminates. An incremental/iterative initial strain algorithm was used in the finite element program. To increase computational efficiency, a 180 deg rotational symmetry relationship was utilized and the finite element program was vectorized to run on a supercomputer. Laminate response was compared to experimentation revealing excellent agreement for both the unnotched and notched angle-ply laminates. Predicted stresses in the region of the hole were examined and are presented, comparing linear elastic analysis to the inelastic endochronic theory analysis. A failure analysis of the unnotched and notched laminates was performed using the quadratic tensor polynomial. Predicted fracture loads compared well with experimentation for the unnotched laminates, but were very conservative in comparison with experiments for the notched laminates.

Application of Dynamic Analysis in Semi-Analytical Finite Element Method

PubMed Central

Oeser, Markus

2017-01-01

Analyses of dynamic responses are significantly important for the design, maintenance and rehabilitation of asphalt pavement. In order to evaluate the dynamic responses of asphalt pavement under moving loads, a specific computational program, SAFEM, was developed based on a semi-analytical finite element method. This method is three-dimensional and only requires a two-dimensional FE discretization by incorporating Fourier series in the third dimension. In this paper, the algorithm to apply the dynamic analysis to SAFEM was introduced in detail. Asphalt pavement models under moving loads were built in the SAFEM and commercial finite element software ABAQUS to verify the accuracy and efficiency of the SAFEM. The verification shows that the computational accuracy of SAFEM is high enough and its computational time is much shorter than ABAQUS. Moreover, experimental verification was carried out and the prediction derived from SAFEM is consistent with the measurement. Therefore, the SAFEM is feasible to reliably predict the dynamic response of asphalt pavement under moving loads, thus proving beneficial to road administration in assessing the pavement’s state. PMID:28867813

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

Lee, Sungsoo, E-mail: sungsoo.lee@utsouthwestern.edu; Wang, Ping-Yuan; Jeong, Yangsik

Oxysterol binding protein related protein 1S (ORP1S) is a member of a family of sterol transport proteins. Here we present evidence that ORP1S translocates from the cytoplasm to the nucleus in response to sterol binding. The sterols that best promote nuclear import of ORP1S also activate the liver X receptor (LXR) transcription factors and we show that ORP1S binds to LXRs, promotes binding of LXRs to LXR response elements (LXREs) and specifically enhances LXR-dependent transcription via the ME.1 and ME.2 enhancer elements of the apoE gene. We propose that ORP1S is a cytoplasmic sterol sensor, which transports sterols to themore » nucleus and promotes LXR-dependent gene transcription through select enhancer elements. -- Highlights: Black-Right-Pointing-Pointer ORP1S translocates to the nucleus in response to sterol binding. Black-Right-Pointing-Pointer The sterols that best promote nuclear import of ORP1S are LXR agonists. Black-Right-Pointing-Pointer ORP1S binds to LXRs, enhances binding of LXRs to LXREs and promotes LXR-dependent transcription of apoE.« less

A mutation in the interferon regulatory element of HBV may influence the response of interferon treatment in chronic hepatitis B patients.

PubMed

Lu, Jia-Jie; Chen, En-Qiang; Yang, Jia-Hong; Zhou, Tao-You; Liu, Li; Tang, Hong

2012-01-10

A functional interferon regulatory element (IRE) has been found in the EnhI/X promoter region of hepatitis B virus (HBV) genome. The purpose of this study is to compare the gene order of responder and non-responder to interferon therapy in patients with chronic hepatitis B (CHB), so as to evaluate the relationship between IRE mutation and the response to interferon treatment for CHB patients. Synthetic therapeutic effect is divided into complete response (CR), partial response (PR) and non-response (NR). Among the 62 cases included in this study, 40 cases (64.5%) were in the response group (CR and PR) and 22 (35.5%) cases were in the NR group. Wild type sequence of HBV IRE TTTCACTTTC were found in 35 cases (56.5%), and five different IRE gene sequences. included TTTtACTTTC, TTTCAtTTTC, TTTtAtTTTC, TTTtACTTTt and cTTtACcTTC, were found in 22 cases (35.5%), 1 case (1.6%), 1 case (1.6%), 2 cases (3.2%) and 1 case (1.6%) respectively. There were 41.9%cases (26/62) with forth base C→T mutation, consisted of 32.5% (13/40) cases in response group and 59.1% (13/22) cases in NR group. Among the 35 cases with IRE sequences, there were 67.5% (27/40) cases in response group and 36.4% (8/22) in NR group, and the difference in IRE sequences between two groups was statistic significantly (P = 0.027). The result suggested that there is likely relationship between the forth base mutation (C→T) of IRE region and the response of HBV to Interferon therapy, and this mutation may partially decrease the inhibition effect of interferon on HBV. The forth base C→T mutation in IRE element of HBV may partially influence the response of Interferon treatment in CHB patients.

The high mobility group protein 1 enhances binding of the estrogen receptor DNA binding domain to the estrogen response element.

PubMed

Romine, L E; Wood, J R; Lamia, L A; Prendergast, P; Edwards, D P; Nardulli, A M

1998-05-01

We have examined the ability of the high-mobility group protein 1 (HMG1) to alter binding of the estrogen receptor DNA-binding domain (DBD) to the estrogen response element (ERE). HMG1 dramatically enhanced binding of purified, bacterially expressed DBD to the consensus vitellogenin A2 ERE in a dose-dependent manner. The ability of HMG1 to stabilize the DBD-ERE complex resulted in part from a decrease in the dissociation rate of the DBD from the ERE. Antibody supershift experiments demonstrated that HMG1 was also capable of forming a ternary complex with the ERE-bound DBD in the presence of HMG1-specific antibody. HMG1 did not substantially affect DBD-ERE contacts as assessed by methylation interference assays, nor did it alter the ability of the DBD to induce distortion in ERE-containing DNA fragments. Because HMG1 dramatically enhanced estrogen receptor DBD binding to the ERE, and the DBD is the most highly conserved region among the nuclear receptor superfamily members, HMG1 may function to enhance binding of other nuclear receptors to their respective response elements and act in concert with coactivator proteins to regulate expression of hormone-responsive genes.

The neurophysiology of figure-ground segregation in primary visual cortex.

PubMed

Lamme, V A

1995-02-01

The activity of neurons in the primary visual cortex of the awake macaque monkey was recorded while the animals were viewing full screen arrays of either oriented line segments or moving random dots. A square patch of the screen was made to perceptually pop out as a circumscribed figure by virtue of differences between the orientation or the direction of motion of the texture elements within that patch and the surround. The animals were trained to identify the figure patches by making saccadic eye movements towards their positions. Almost every cell gave a significantly larger response to elements belonging to the figure than to similar elements belonging to the background. The figure-ground response enhancement was present along the entire extent of the patch and was absent as soon as the receptive field was outside the patch. The strength of the effect had no relation with classical receptive field properties like orientation or direction selectivity or receptive field size. The response enhancement had a latency of 30-40 msec relative to the onset of the neuronal response itself. The results show that context modulation within primary visual cortex has a highly sophisticated nature, putting the image features the cells are responding to into their fully evaluated perceptual context.

P Element Transposition Contributes Substantial New Variation for a Quantitative Trait in Drosophila Melanogaster

PubMed Central

Torkamanzehi, A.; Moran, C.; Nicholas, F. W.

1992-01-01

The P-M system of transposition in Drosophila melanogaster is a powerful mutator for many visible and lethal loci. Experiments using crosses between unrelated P and M stocks to assess the importance of transposition-mediated mutations affecting quantitative loci and reponse to selection have yielded unrepeatable or ambiguous results. In a different approach, we have used a P stock produced by microinjection of the ry(506) M stock. Selection responses were compared between transposition lines that were initiated by crossing M strain females with males from the ``co-isogenic'' P strain, and ry(506) M control lines. Unlike previous attempts to quantify the effects of P element transposition, there is no possibility of P transposition in the controls. During 10 generations of selection for the quantitative trait abdominal bristle number, none of the four control lines showed any response to selection, indicative of isogenicity for those loci affecting abdominal bristle number. In contrast, three of the four transposition lines showed substantial response, with regression of cumulative response on cumulative selection differential ranging from 15% to 25%. Transposition of P elements has produced new additive genetic variance at a rate which is more than 30 times greater than the rate expected from spontaneous mutation. PMID:1317317

Studies on the mechanism of functional cooperativity between progesterone and estrogen receptors.

PubMed

Bradshaw, M S; Tsai, S Y; Leng, X H; Dobson, A D; Conneely, O M; O'Malley, B W; Tsai, M J

1991-09-05

Steroid response elements (SREs) cooperate with many different cis-acting elements including NF-1 sites, CACCC boxes, and other SREs to induce target gene expression (Schule, R., Muller, M., Otsuka-Murakami, H., and Renkawitz, R. (1988) Nature 332, 87-90; Strahle, U., Schmid, W., and Schutz, G. (1988) EMBO J. 7, 3389-3395). Induction of gene expression can be additive or synergistic with respect to the level of activation by either transactivators. Two mechanisms have been proposed for how synergism occurs: 1) cooperative binding of transcriptional activators to DNA or 2) simultaneous interaction of individually bound activators with a common target protein. We have shown previously that cooperative binding of receptors is important for synergism between two progesterone response elements (PREs). Here we showed that an estrogen response element (ERE) and a PRE can also functionally cooperate and this synergism between an ERE and a PRE is not contributed by cooperative DNA binding. Furthermore, we have demonstrated that the activation domains of the progesterone receptor (PR) (C1Act) are required for synergism between two PREs and sufficient for confirming cooperative binding. However these two activation domains of PR are not sufficient for synergism between an ERE and a PRE. Additional regions within the NH2-terminal and COOH-terminal domains are also required for synergistic interaction between two heterologous SREs.

[Synthesis of strontium-containing porous hydroxyaptite ceramics and study of its biological properties].

PubMed

Zou, Wen; Ran, Xu; Liang, Jie; Chen, Hezhong; Luo, Jiaoming

2012-12-01

Strontium added into porous hydroxyaptite ceramics has the functions of improving its osseointegration, decreasing its dissolution rate and improving the bone density. Strontium-containing hydroxyaptite (Sr-HA) ceramics has been used as bone replacement and scaffold to treat the osteoporosis and bone default in clinic, but the mechanism of interfacial tissue response caused by the trace element Sr in Sr-HA ceramics still remains to be further studied. Four types of Sr-HA ceramic samples with different contents of Sr were prepared by microwave plasma sintering for testing the response of the soft tissue implanted in dog muscles in our laboratory. The contents of Sr element in the samples are 0 mol%, 1 mol%, 5 mol%, and 7 mol%, respectively. The samples were implanted in the muscle of the dogs for 4 weeks, 8 weeks and 12 weeks, respectively. The histological observations at the end of each period showed that the irritant ranking increased with the content of Sr in Sr-HA ceramics at the end of 12 weeks, and there were rich bone tissue in Sr-HA ceramic samples with 5 mol% Sr element. The overdose of element Sr is harmful to soft tissues. When the content of Sr in Sr-HA ceramic was below 5 mol%, the soft tissue response was very slight and the new bones were induced to grow well.

Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption.

PubMed

Echeverría, Jesús C; Calleja, Ignacio; Moriones, Paula; Garrido, Julián J

2017-01-01

We investigated the response of three fiber optic sensing elements prepared at pH 10 from phenyltriethoxysilane (PhTEOS) and tetraethylsilane (TEOS) mixtures with 30, 40, and 50% PhTEOS in the silicon precursor mixture. The sensing elements are referred to as Ph30, Ph40 and Ph50, respectively. The films were synthesized by the sol-gel method and affixed to the end of optical fibers by the dip-coating technique. Fourier transform infrared spectroscopy, N 2 adsorption-desorption at 77 K and X-ray diffraction analysis were used to characterize the xerogels. At a given pressure of n -hexane, the response of each sensing element decreased with temperature, indicating an exothermic process that confirmed the role of adsorption in the overall performance of the sensing elements. The isosteric adsorption enthalpies were obtained from the calibration curves at different temperatures. The magnitude of the isosteric enthalpy of n -hexane increased with the relative response and reached a plateau that stabilized at approximately -31 kJ mol -1 for Ph40 and Ph50 and at approximately -37 kJ mol -1 for Ph30. This indicates that the adsorbate-adsorbent interaction was dominant at lower relative pressure and condensation of the adsorbate on the mesopores was dominant at higher relative pressure.

Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption

PubMed Central

Calleja, Ignacio; Moriones, Paula; Garrido, Julián J

2017-01-01

We investigated the response of three fiber optic sensing elements prepared at pH 10 from phenyltriethoxysilane (PhTEOS) and tetraethylsilane (TEOS) mixtures with 30, 40, and 50% PhTEOS in the silicon precursor mixture. The sensing elements are referred to as Ph30, Ph40 and Ph50, respectively. The films were synthesized by the sol–gel method and affixed to the end of optical fibers by the dip-coating technique. Fourier transform infrared spectroscopy, N2 adsorption–desorption at 77 K and X-ray diffraction analysis were used to characterize the xerogels. At a given pressure of n-hexane, the response of each sensing element decreased with temperature, indicating an exothermic process that confirmed the role of adsorption in the overall performance of the sensing elements. The isosteric adsorption enthalpies were obtained from the calibration curves at different temperatures. The magnitude of the isosteric enthalpy of n-hexane increased with the relative response and reached a plateau that stabilized at approximately −31 kJ mol−1 for Ph40 and Ph50 and at approximately −37 kJ mol−1 for Ph30. This indicates that the adsorbate–adsorbent interaction was dominant at lower relative pressure and condensation of the adsorbate on the mesopores was dominant at higher relative pressure. PMID:28326238

Reading for a Better World: Teaching for Social Responsibility with Young Adult Literature

ERIC Educational Resources Information Center

Wolk, Steven

2009-01-01

Teaching for social responsibility should be one of the vital aims of our schools. Young adult literature offers an authentic, meaningful, and critical way to teach for social responsibility. This article offers an overview of the different elements of social responsibility and some young adult novels and graphic novels that could be used to teach…

Two-Dimensional Finite Element Ablative Thermal Response Analysis of an Arcjet Stagnation Test

NASA Technical Reports Server (NTRS)

Dec, John A.; Laub, Bernard; Braun, Robert D.

2011-01-01

The finite element ablation and thermal response (FEAtR, hence forth called FEAR) design and analysis program simulates the one, two, or three-dimensional ablation, internal heat conduction, thermal decomposition, and pyrolysis gas flow of thermal protection system materials. As part of a code validation study, two-dimensional axisymmetric results from FEAR are compared to thermal response data obtained from an arc-jet stagnation test in this paper. The results from FEAR are also compared to the two-dimensional axisymmetric computations from the two-dimensional implicit thermal response and ablation program under the same arcjet conditions. The ablating material being used in this arcjet test is phenolic impregnated carbon ablator with an LI-2200 insulator as backup material. The test is performed at the NASA, Ames Research Center Interaction Heating Facility. Spatially distributed computational fluid dynamics solutions for the flow field around the test article are used for the surface boundary conditions.

Two-dimensional finite-element analyses of simulated rotor-fragment impacts against rings and beams compared with experiments

NASA Technical Reports Server (NTRS)

Stagliano, T. R.; Witmer, E. A.; Rodal, J. J. A.

1979-01-01

Finite element modeling alternatives as well as the utility and limitations of the two dimensional structural response computer code CIVM-JET 4B for predicting the transient, large deflection, elastic plastic, structural responses of two dimensional beam and/or ring structures which are subjected to rigid fragment impact were investigated. The applicability of the CIVM-JET 4B analysis and code for the prediction of steel containment ring response to impact by complex deformable fragments from a trihub burst of a T58 turbine rotor was studied. Dimensional analysis considerations were used in a parametric examination of data from engine rotor burst containment experiments and data from sphere beam impact experiments. The use of the CIVM-JET 4B computer code for making parametric structural response studies on both fragment-containment structure and fragment-deflector structure was illustrated. Modifications to the analysis/computation procedure were developed to alleviate restrictions.

NAC transcription factor genes: genome-wide identification, phylogenetic, motif and cis-regulatory element analysis in pigeonpea (Cajanus cajan (L.) Millsp.).

PubMed

Satheesh, Viswanathan; Jagannadham, P Tej Kumar; Chidambaranathan, Parameswaran; Jain, P K; Srinivasan, R

2014-12-01

The NAC (NAM, ATAF and CUC) proteins are plant-specific transcription factors implicated in development and stress responses. In the present study 88 pigeonpea NAC genes were identified from the recently published draft genome of pigeonpea by using homology based and de novo prediction programmes. These sequences were further subjected to phylogenetic, motif and promoter analyses. In motif analysis, highly conserved motifs were identified in the NAC domain and also in the C-terminal region of the NAC proteins. A phylogenetic reconstruction using pigeonpea, Arabidopsis and soybean NAC genes revealed 33 putative stress-responsive pigeonpea NAC genes. Several stress-responsive cis-elements were identified through in silico analysis of the promoters of these putative stress-responsive genes. This analysis is the first report of NAC gene family in pigeonpea and will be useful for the identification and selection of candidate genes associated with stress tolerance.

Toward the way forward: the national children's disaster mental health concept of operations.

PubMed

Schreiber, Merritt; Pfefferbaum, Betty; Sayegh, Lisa

2012-06-01

Although increasing evidence suggests that children are at particular risk from disasters and evidence-based practices have been developed to triage and treat them effectively, no strategy or concept of operations linking best practices for disaster response is currently in place. To our knowledge, this report describes the first effort to address this critical gap and outlines a triage-driven children's disaster mental health incident response strategy for seamless preparedness, response, and recovery elements that can be used now. The national children's disaster mental health concept of operations (NCDMH CONOPS) details the essential elements needed for an interoperable, coordinated response for the mental health needs of children by local communities, counties, regions, and states to better meet the needs of children affected by disasters and terrorism incidents. This CONOPS for children proposes the use of an evidence-based, rapid triage system to provide a common data metric to incident response and recovery action and to rationally align limited resources to those at greater need in a population-based approach.

Deciphering RNA Regulatory Elements Involved in the Developmental and Environmental Gene Regulation of Trypanosoma brucei.

PubMed

Gazestani, Vahid H; Salavati, Reza

2015-01-01

Trypanosoma brucei is a vector-borne parasite with intricate life cycle that can cause serious diseases in humans and animals. This pathogen relies on fine regulation of gene expression to respond and adapt to variable environments, with implications in transmission and infectivity. However, the involved regulatory elements and their mechanisms of actions are largely unknown. Here, benefiting from a new graph-based approach for finding functional regulatory elements in RNA (GRAFFER), we have predicted 88 new RNA regulatory elements that are potentially involved in the gene regulatory network of T. brucei. We show that many of these newly predicted elements are responsive to both transcriptomic and proteomic changes during the life cycle of the parasite. Moreover, we found that 11 of predicted elements strikingly resemble previously identified regulatory elements for the parasite. Additionally, comparison with previously predicted motifs on T. brucei suggested the superior performance of our approach based on the current limited knowledge of regulatory elements in T. brucei.

Layerwise Mechanics and Finite Elements for Smart Composite Structures with Piezoelectric Actuators and Sensors

NASA Technical Reports Server (NTRS)

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

1996-01-01

Recent developments on layerwise mechanics for the analysis of composite laminates and structures with piezoelectric actuators and sensors are reviewed. The mechanics implement layerwise representations of displacements and electric potential, and can model both the global and local electromechanical response of smart composite structures. The corresponding finite-element implementations for the static and dynamic analysis of smart piezoelectric composite structures are also summarized. Select application illustrate the accuracy, robustness and capability of the developed mechanics to capture the global and local dynamic response of thin and/or thick laminated piezoelectric plates.

Thermoviscoplastic response of thin plates subjected to intense local heating

NASA Technical Reports Server (NTRS)

Byrom, Ted G.; Allen, David H.; Thornton, Earl A.

1992-01-01

A finite element method is employed to investigate the thermoviscoplastic response of a half-cylinder to intense localized transient heating. Thermoviscoplastic material behavior is characterized by the Bodner-Partom constitutive model. Structure geometry is modeled with a three-dimensional assembly of CST-DKT plate elements incorporating the large deflection von Karman assumptions. The paper compares the results of a dynamic analysis with a quasi-static analysis for the half-cylinder structure with a step-function transient temperature loading similar to that which may be encountered with shock wave interference on a hypersonic leading edge.

Vibration response of spalled rolling element bearings: Observations, simulations and signal processing techniques to track the spall size

NASA Astrophysics Data System (ADS)

Sawalhi, N.; Randall, R. B.

2011-04-01

Fatigue in rolling element bearings, resulting in spalling of the races and/or rolling elements, is the most common cause of bearing failure. The useful life of the bearing may extend considerably beyond the appearance of the first spall and a premature removal of the bearing from service can be very expensive, but on the other hand chances cannot be taken with safety of machines or personnel. Previous studies indicated that there might be two parts to the defect vibration signal of a spalled bearing, the first part being originating from the entry of the rolling element into the fault (de-stress) and the second part being due to the departure of the rolling element from the fault (re-stress). This is investigated in this paper using vibration signatures of seeded faults at different speeds. The acceleration signals resulting from the entry of the rolling element into the spall and exit from it were found to be of different natures. The entry into the fault can be described as a step response, with mainly low frequency content, while the impact excites a much broader frequency impulse response. The latter is the most noticeable and prominent event, especially when examining the high pass filtered response or the enveloped signal. In order to enable a clear separation of the two events, and produce an averaged estimate of the size of the fault, two approaches are proposed to enhance the entry event while keeping the impulse response. The first approach (joint treatment) utilizes pre-whitening to balance the low and high frequency energy, then octave band wavelet analysis to allow selection of the best band (or scale) to balance the two pulses with similar frequency content. In the second approach, a separate treatment is applied to the step and the impulse responses, so that they can be equally represented in the signal. Cepstrum analysis can be used to give an average estimate of the spacing between the entry and impact events, but the latter can also be assessed by an arithmetic estimation of the mean and standard deviation of the event separation for a number of realizations, in particular for the second approach. In order to determine the effects of various simulations and signal processing parameters on the estimated delay times, the entry and exit events were simulated as modified step and impulse responses with precisely known starting times. The simulation was also found useful in pointing to artefacts associated with the cepstrum calculation, which affect even the simulated signals, and have thus prompted modifications of the processing of real signals. The results presented for the two approaches give a reasonable approximation of the measured fault widths (double the spacing between the entry and impact events) under different speed conditions, but the method of separate treatment is somewhat better and is thus recommended.

A Comparison of Nonlinear Filters for Orbit Determination and Estimation

DTIC Science & Technology

1986-06-01

Com- mand uses a nonlinear least squares filter for element set maintenance for all objects orbiting the Earth (3). These objects, including active...initial state vector is the singularly averaged classical orbital element set provided by SPACECOM/DOA. The state vector in this research consists of...GSF (G) - - 26.0 36.7 GSF(A) 32.1 77.4 38.8 59.6 The Air Force Space Command is responsible for main- taining current orbital element sets for about

Piezoelectrically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Thundat, Thomas G.; Wachter, Eric A.

2002-01-01

Methods and apparatus for detecting particular frequencies of acoustic vibration utilize a piezoelectrically-tunable beam element having a piezoelectric layer and a stress sensitive layer and means for providing an electrical potential across the piezoelectric layer to controllably change the beam's stiffness and thereby change its resonance frequency. It is then determined from the response of the piezoelectrically-tunable beam element to the acoustical vibration to which the beam element is exposed whether or not a particular frequency or frequencies of acoustic vibration are detected.

Incorporating general race and housing flexibility and deadband in rolling element bearing analysis

NASA Technical Reports Server (NTRS)

Davis, R. R.; Vallance, C. S.

1989-01-01

Methods for including the effects of general race and housing compliance and outer race-to-housing deadband (clearance) in rolling element bearing mechanics analysis is presented. It is shown that these effects can cause significant changes in bearing stiffness characteristics, which are of major importance in rotordynamic response of turbomachinery and other rotating systems. Preloading analysis is demonstrated with the finite element/contact mechanics hybrid method applied to a 45 mm angular contact ball bearing.

A sensitive and quantitative element-tagged immunoassay with ICPMS detection.

PubMed

Baranov, Vladimir I; Quinn, Zoë; Bandura, Dmitry R; Tanner, Scott D

2002-04-01

We report a set of novel immunoassays in which proteins of interest can be detected using specific element-tagged antibodies. These immunoassays are directly coupled with an inductively coupled plasma mass spectrometer (ICPMS) to quantify the elemental (in this work, metal) component of the reacted tagged antibodies. It is demonstrated that these methods can detect levels of target proteins as low as 0.1-0.5 ng/mL and yield a linear response to protein concentration over 3 orders of magnitude.

Implementation of Free-Formulation-Based Flat Shell Elements into NASA Comet Code and Development of Nonlinear Shallow Shell Element

NASA Technical Reports Server (NTRS)

Barut, A.; Madenci, Erdogan; Tessler, A.

1997-01-01

This study presents a transient nonlinear finite element analysis within the realm of a multi-body dynamics formulation for determining the dynamic response of a moderately thick laminated shell undergoing a rapid and large rotational motion and nonlinear elastic deformations. Nonlinear strain measure and rotation, as well as 'the transverse shear deformation, are explicitly included in the formulation in order to capture the proper motion-induced stiffness of the laminate. The equations of motion are derived from the virtual work principle. The analysis utilizes a shear deformable shallow shell element along with the co-rotational form of the updated Lagrangian formulation. The shallow shell element formulation is based on the Reissner-Mindlin and Marguerre theory.

Broadband gradient index microwave quasi-optical elements based on non-resonant metamaterials.

PubMed

Liu, Ruopeng; Cheng, Qiang; Chin, Jessie Y; Mock, Jack J; Cui, Tie Jun; Smith, David R

2009-11-09

Utilizing non-resonant metamaterial elements, we demonstrate that complex gradient index optics can be constructed exhibiting low material losses and large frequency bandwidth. Although the range of structures is limited to those having only electric response, with an electric permittivity always equal to or greater than unity, there are still numerous metamaterial design possibilities enabled by leveraging the non-resonant elements. For example, a gradient, impedance matching layer can be added that drastically reduces the return loss of the optical elements due to reflection. In microwave experiments, we demonstrate the broadband design concepts with a gradient index lens and a beam-steering element, both of which are confirmed to operate over the entire X-band (roughly 8-12 GHz) frequency spectrum.

Seedling establishment and physiological responses to temporal and spatial soil moisture changes

Treesearch

Jeremy Pinto; John D. Marshall; Kas Dumroese; Anthony S. Davis; Douglas R. Cobos

2016-01-01

In many forests of the world, the summer season (temporal element) brings drought conditions causing low soil moisture in the upper soil profile (spatial element) - a potentially large barrier to seedling establishment. We evaluated the relationship between initial seedling root depth, temporal and spatial changes in soil moisture during drought after...

Film: An Introduction.

ERIC Educational Resources Information Center

Fell, John L.

"Understanding Film," the opening section of this book, discusses perceptions of and responses to film and the way in which experiences with and knowledge of other media affect film viewing. The second section, "Film Elements," analyzes the basic elements of film: the use of space and time, the impact of editing, sound and color, and the effects…

Cognitive Responses to Sociocultural Elements in Professional Graduate Programs: Two Case Studies

ERIC Educational Resources Information Center

Uhrig, Karl

2012-01-01

This article examines the sociocognitive context of two international students in academic programs in the United States. Bandura (2001) defines sociocognition as the interaction between an individual and the sociocultural elements that comprise his or her learning environment. Research in English for academic purposes has included more focus on…

Communicating the Garifuna Culture in Contemporary Church Music

ERIC Educational Resources Information Center

Norales, Francisca

2011-01-01

The manner in which a person views the universe originates from her/his culture. If someone should be asked of the predominant element found in every culture that has for centuries given people their perspective of the universe, certainly, the answer would be, Religion! The responsibility of generating and preserving the elements of one's…

Necessary Elements of Civic Engagement in Teacher Education

ERIC Educational Resources Information Center

Fernlund, Phyllis

2011-01-01

In this paper, the author discusses the necessary elements of civic engagement in teacher education and responsibility for schools. For over 50 years, John Goodlad conducted research, created an institute to study education in a democratic society, and formed 25 partnership sites to engage in research and practice. The National Network for Renewal…

Over-Selectivity as a Learned Response

ERIC Educational Resources Information Center

Reed, Phil; Petrina, Neysa; McHugh, Louise

2011-01-01

An experiment investigated the effects of different levels of task complexity in pre-training on over-selectivity in a subsequent match-to-sample (MTS) task. Twenty human participants were divided into two groups; exposed either to a 3-element, or a 9-element, compound stimulus as a sample during MTS training. After the completion of training,…

Nonlinear probabilistic finite element models of laminated composite shells

NASA Technical Reports Server (NTRS)

Engelstad, S. P.; Reddy, J. N.

1993-01-01

A probabilistic finite element analysis procedure for laminated composite shells has been developed. A total Lagrangian finite element formulation, employing a degenerated 3-D laminated composite shell with the full Green-Lagrange strains and first-order shear deformable kinematics, forms the modeling foundation. The first-order second-moment technique for probabilistic finite element analysis of random fields is employed and results are presented in the form of mean and variance of the structural response. The effects of material nonlinearity are included through the use of a rate-independent anisotropic plasticity formulation with the macroscopic point of view. Both ply-level and micromechanics-level random variables can be selected, the latter by means of the Aboudi micromechanics model. A number of sample problems are solved to verify the accuracy of the procedures developed and to quantify the variability of certain material type/structure combinations. Experimental data is compared in many cases, and the Monte Carlo simulation method is used to check the probabilistic results. In general, the procedure is quite effective in modeling the mean and variance response of the linear and nonlinear behavior of laminated composite shells.

Curved Thermopiezoelectric Shell Structures Modeled by Finite Element Analysis

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun

2000-01-01

"Smart" structures composed of piezoelectric materials may significantly improve the performance of aeropropulsion systems through a variety of vibration, noise, and shape-control applications. The development of analytical models for piezoelectric smart structures is an ongoing, in-house activity at the NASA Glenn Research Center at Lewis Field focused toward the experimental characterization of these materials. Research efforts have been directed toward developing analytical models that account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. Current work revolves around implementing thermal effects into a curvilinear-shell finite element code. This enhances capabilities to analyze curved structures and to account for coupling effects arising from thermal effects and the curved geometry. The current analytical model implements a unique mixed multi-field laminate theory to improve computational efficiency without sacrificing accuracy. The mechanics can model both the sensory and active behavior of piezoelectric composite shell structures. Finite element equations are being implemented for an eight-node curvilinear shell element, and numerical studies are being conducted to demonstrate capabilities to model the response of curved piezoelectric composite structures (see the figure).

Test-Analysis Correlation of a Crash Simulation of a Vertical Drop Test of a Commuter-Category Aircraft

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.

2004-01-01

A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-feet per second (9.14-meters per second) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kilograms) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, simulated engines and fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial finite element code for performing explicit transient dynamic simulations. Analytical predictions of structural deformation and selected time-history responses were correlated with experimental data from the drop test to validate the simulation.

Studies of biaxial mechanical properties and nonlinear finite element modeling of skin.

PubMed

Shang, Xituan; Yen, Michael R T; Gaber, M Waleed

2010-06-01

The objective of this research is to conduct mechanical property studies of skin from two individual but potentially connected aspects. One is to determine the mechanical properties of the skin experimentally by biaxial tests, and the other is to use the finite element method to model the skin properties. Dynamic biaxial tests were performed on 16 pieces of abdominal skin specimen from rats. Typical biaxial stress-strain responses show that skin possesses anisotropy, nonlinearity and hysteresis. To describe the stress-strain relationship in forms of strain energy function, the material constants of each specimen were obtained and the results show a high correlation between theory and experiments. Based on the experimental results, a finite element model of skin was built to model the skin's special properties including anisotropy and nonlinearity. This model was based on Arruda and Boyce's eight-chain model and Bischoff et al.'s finite element model of skin. The simulation results show that the isotropic, nonlinear eight-chain model could predict the skin's anisotropic and nonlinear responses to biaxial loading by the presence of an anisotropic prestress state.

Application of the Spectral Element Method to Acoustic Radiation

NASA Technical Reports Server (NTRS)

Doyle, James F.; Rizzi, Stephen A. (Technical Monitor)

2000-01-01

This report summarizes research to develop a capability for analysis of interior noise in enclosed structures when acoustically excited by an external random source. Of particular interest was the application to the study of noise and vibration transmission in thin-walled structures as typified by aircraft fuselages. Three related topics are focused upon. The first concerns the development of a curved frame spectral element, the second shows how the spectral element method for wave propagation in folded plate structures is extended to problems involving curved segmented plates. These are of significance because by combining these curved spectral elements with previously presented flat spectral elements, the dynamic response of geometrically complex structures can be determined. The third topic shows how spectral elements, which incorporate the effect of fluid loading on the structure, are developed for analyzing acoustic radiation from dynamically loaded extended plates.

Theoretical and experimental investigation of architected core materials incorporating negative stiffness elements

NASA Astrophysics Data System (ADS)

Chang, Chia-Ming; Keefe, Andrew; Carter, William B.; Henry, Christopher P.; McKnight, Geoff P.

2014-04-01

Structural assemblies incorporating negative stiffness elements have been shown to provide both tunable damping properties and simultaneous high stiffness and damping over prescribed displacement regions. In this paper we explore the design space for negative stiffness based assemblies using analytical modeling combined with finite element analysis. A simplified spring model demonstrates the effects of element stiffness, geometry, and preloads on the damping and stiffness performance. Simplified analytical models were validated for realistic structural implementations through finite element analysis. A series of complementary experiments was conducted to compare with modeling and determine the effects of each element on the system response. The measured damping performance follows the theoretical predictions obtained by analytical modeling. We applied these concepts to a novel sandwich core structure that exhibited combined stiffness and damping properties 8 times greater than existing foam core technologies.

Life assessment of structural components using inelastic finite element analyses

NASA Technical Reports Server (NTRS)

Arya, Vinod K.; Halford, Gary R.

1993-01-01

The need for enhanced and improved performance of structural components subject to severe cyclic thermal/mechanical loadings, such as in the aerospace industry, requires development of appropriate solution technologies involving time-dependent inelastic analyses. Such analyses are mandatory to predict local stress-strain response and to assess more accurately the cyclic life time of structural components. The NASA-Lewis Research Center is cognizant of this need. As a result of concerted efforts at Lewis during the last few years, several such finite element solution technologies (in conjunction with the finite element program MARC) were developed and successfully applied to numerous uniaxial and multiaxial problems. These solution technologies, although developed for use with MARC program, are general in nature and can easily be extended for adaptation with other finite element programs such as ABAQUS, ANSYS, etc. The description and results obtained from two such inelastic finite element solution technologies are presented. The first employs a classical (non-unified) creep-plasticity model. An application of this technology is presented for a hypersonic inlet cowl-lip problem. The second of these technologies uses a unified creep-plasticity model put forth by Freed. The structural component for which this finite element solution technology is illustrated, is a cylindrical rocket engine thrust chamber. The advantages of employing a viscoplastic model for nonlinear time-dependent structural analyses are demonstrated. The life analyses for cowl-lip and cylindrical thrust chambers are presented. These analyses are conducted by using the stress-strain response of these components obtained from the corresponding finite element analyses.

Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

PubMed

Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

2011-04-01

Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

Cassava C-repeat binding factor 1 gene responds to low temperature and enhances cold tolerance when overexpressed in Arabidopsis and cassava.

PubMed

An, Dong; Ma, Qiuxiang; Wang, Hongxia; Yang, Jun; Zhou, Wenzhi; Zhang, Peng

2017-05-01

Cassava MeCBF1 is a typical CBF transcription factor mediating cold responses but its low expression in apical buds along with a retarded response cause inefficient upregulation of downstream cold-related genes, rendering cassava chilling-sensitive. Low temperature is a major abiotic stress factor affecting survival, productivity and geographic distribution of important crops worldwide. The C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB) are important regulators of abiotic stress response in plants. In this study, MeCBF1, a CBF-like gene, was identified in the tropical root crop cassava (Manihot esculenta Crantz). The MeCBF1 encodes a protein that shares strong homology with DREB1As/CBFs from Arabidopsis as well as other species. The MeCBF1 was localized to the nucleus and is mainly expressed in stem and mature leaves, but not in apical buds or stem cambium. MeCBF1 expression was not only highly responsive to cold, but also significantly induced by salt, PEG and ABA treatment. Several stress-associated cis-elements were found in its promoter region, e.g., ABRE-related, MYC recognition sites, and MYB responsive element. Compared with AtCBF1, the MeCBF1 expression induced by cold in cassava was retarded and upregulated only after 4 h, which was also confirmed by its promoter activity. Overexpression of MeCBF1 in transgenic Arabidopsis and cassava plants conferred enhanced crytolerance. The CBF regulon was smaller and not entirely co-regulated with MeCBF1 expression in overexpressed cassava. The retarded MeCBF1 expression in response to cold and attenuated CBF-regulon might lead cassava to chilling sensitivity.

The Specificity of Innate Immune Responses Is Enforced by Repression of Interferon Response Elements by NF-κB p50

PubMed Central

Cheng, Christine S.; Feldman, Kristyn E.; Lee, James; Verma, Shilpi; Huang, De-Bin; Huynh, Kim; Chang, Mikyoung; Ponomarenko, Julia V.; Sun, Shao-Cong; Benedict, Chris A.; Ghosh, Gourisankar; Hoffmann, Alexander

2011-01-01

The specific binding of transcription factors to cognate sequence elements is thought to be critical for the generation of specific gene expression programs. Members of the nuclear factor κB (NF-κB) and interferon (IFN) regulatory factor (IRF) transcription factor families bind to the κB site and the IFN response element (IRE), respectively, of target genes, and they are activated in macrophages after exposure to pathogens. However, how these factors produce pathogen-specific inflammatory and immune responses remains poorly understood. Combining top-down and bottom-up systems biology approaches, we have identified the NF-κB p50 homodimer as a regulator of IRF responses. Unbiased genome-wide expression and biochemical and structural analyses revealed that the p50 homodimer repressed a subset of IFN-inducible genes through a previously uncharacterized subclass of guanine-rich IRE (G-IRE) sequences. Mathematical modeling predicted that the p50 homodimer might enforce the stimulus specificity of composite promoters. Indeed, the production of the antiviral regulator IFN-β was rendered stimulus-specific by the binding of the p50 homodimer to the G-IRE–containing IFNβ enhancer to suppress cytotoxic IFN signaling. Specifically, a deficiency in p50 resulted in the inappropriate production of IFN-β in response to bacterial DNA sensed by Toll-like receptor 9. This role for the NF-κB p50 homodimer in enforcing the specificity of the cellular response to pathogens by binding to a subset of IRE sequences alters our understanding of how the NF-κB and IRF signaling systems cooperate to regulate antimicrobial immunity. PMID:21343618

The human haptoglobin gene promoter: interleukin-6-responsive elements interact with a DNA-binding protein induced by interleukin-6.

PubMed Central

Oliviero, S; Cortese, R

1989-01-01

Transcription of the human haptoglobin (Hp) gene is induced by interleukin-6 (IL-6) in the human hepatoma cell line Hep3B. Cis-acting elements responsible for this response are localized within the first 186 bp of the 5'-flanking region. Site-specific mutants of the Hp promoter fused to the chloramphenicol acetyl transferase (CAT) gene were analysed by transient transfection into uninduced and IL-6-treated Hep3B cells. We identified three regions, A, B and C, defined by mutation, which are important for the IL-6 response. Band shift experiments using nuclear extracts from untreated or IL-6-treated cells revealed the presence of IL-6-inducible DNA binding activities when DNA fragments containing the A or the C sequences were used. Competition experiments showed that both sequences bind to the same nuclear factors. Polymers of oligonucleotides containing either the A or the C regions confer IL-6 responsiveness to a truncated SV40 promoter. The B region forms several complexes with specific DNA-binding proteins different from those which bind to the A and C region. The B region complexes are identical in nuclear extracts from IL-6-treated and untreated cells. While important for IL-6 induction in the context of the haptoglobin promoter, the B site does not confer IL-6 inducibility to the SV40 promoter. Our results indicate that the IL-6 response of the haptoglobin promoter is dependent on the presence of multiple, partly redundant, cis-acting elements. Images PMID:2787245

Meta-analysis of the effect of overexpression of CBF/DREB family genes on drought stress response

USDA-ARS?s Scientific Manuscript database

Transcription factors C-repeat/dehydration-responsive element binding proteins (CBF/DREB) play an important role in plant response to abiotic stresses. Over-expression of various CBF/DREB genes in diverse plants have been reported, but inconsistency of gene donor, recipient genus, parameters used i...

Primary School Pupils' Response to Audio-Visual Learning Process in Port-Harcourt

ERIC Educational Resources Information Center

Olube, Friday K.

2015-01-01

The purpose of this study is to examine primary school children's response on the use of audio-visual learning processes--a case study of Chokhmah International Academy, Port-Harcourt (owned by Salvation Ministries). It looked at the elements that enhance pupils' response to educational television programmes and their hindrances to these…

Finite element modeling of hyper-viscoelasticity of peripheral nerve ultrastructures.

PubMed

Chang, Cheng-Tao; Chen, Yu-Hsing; Lin, Chou-Ching K; Ju, Ming-Shaung

2015-07-16

The mechanical characteristics of ultrastructures of rat sciatic nerves were investigated through animal experiments and finite element analyses. A custom-designed dynamic testing apparatus was used to conduct in vitro transverse compression experiments on the nerves. The optical coherence tomography (OCT) was utilized to record the cross-sectional images of nerve during the dynamic testing. Two-dimensional finite element models of the nerves were built based on their OCT images. A hyper-viscoelastic model was employed to describe the elastic and stress relaxation response of each ultrastructure of the nerve, namely the endoneurium, the perineurium and the epineurium. The first-order Ogden model was employed to describe the elasticity of each ultrastructure and a generalized Maxwell model for the relaxation. The inverse finite element analysis was used to estimate the material parameters of the ultrastructures. The results show the instantaneous shear modulus of the ultrastructures in decreasing order is perineurium, endoneurium, and epineurium. The FE model combined with the first-order Ogden model and the second-order Prony series is good enough for describing the compress-and-hold response of the nerve ultrastructures. The integration of OCT and the nonlinear finite element modeling may be applicable to study the viscoelasticity of peripheral nerve down to the ultrastructural level. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heavy element synthesis in the oldest stars and the early Universe.

PubMed

Cowan, John J; Sneden, Christopher

2006-04-27

The first stars in the Universe were probably quite different from those born today. Composed almost entirely of hydrogen and helium (plus a tiny trace of lithium), they lacked the heavier elements that determine the formation and evolution of younger stars. Although we cannot observe the very first stars--they died long ago in supernovae explosions--they created heavy elements that were incorporated into the next generation. Here we describe how observations of heavy elements in the oldest surviving stars in our Galaxy's halo help us understand the nature of the first stars--those responsible for the chemical enrichment of our Galaxy and Universe.

Elemental X-ray mapping of agglutinated foraminifer tests: A non- destructive technique for determining compositional characteristics.

USGS Publications Warehouse

Commeau, R.F.; Reynolds, Leslie A.; Poag, C.W.

1985-01-01

The composition of agglutinated foraminiferal tests vary remarkably in response to local substrate characteristics, physiochemical properties of the water column and species- dependant selectivity of test components. We have employed a technique that combines a scanning electron microscope with an energy dispersive X-ray spectrometer system to identify major and minor elemental constituents of agglutinated foraminiferal walls. As a sample is bombarded with a beam of high energy electrons, X-rays are generated that are characteristic of the elements present. As a result, X- ray density maps can be produced for each of several elements present in the tests of agglutinated foraminifers. 

On the Finite Element Implementation of the Generalized Method of Cells Micromechanics Constitutive Model

NASA Technical Reports Server (NTRS)

Wilt, T. E.

1995-01-01

The Generalized Method of Cells (GMC), a micromechanics based constitutive model, is implemented into the finite element code MARC using the user subroutine HYPELA. Comparisons in terms of transverse deformation response, micro stress and strain distributions, and required CPU time are presented for GMC and finite element models of fiber/matrix unit cell. GMC is shown to provide comparable predictions of the composite behavior and requires significantly less CPU time as compared to a finite element analysis of the unit cell. Details as to the organization of the HYPELA code are provided with the actual HYPELA code included in the appendix.

Nonlinear vibrations of thin arbitrarily laminated composite plates subjected to harmonic excitations using DKT elements

NASA Astrophysics Data System (ADS)

Chiang, C. K.; Xue, David Y.; Mei, Chuh

1993-04-01

A finite element formulation is presented for determining the large-amplitude free and steady-state forced vibration response of arbitrarily laminated anisotropic composite thin plates using the Discrete Kirchhoff Theory (DKT) triangular elements. The nonlinear stiffness and harmonic force matrices of an arbitrarily laminated composite triangular plate element are developed for nonlinear free and forced vibration analyses. The linearized updated-mode method with nonlinear time function approximation is employed for the solution of the system nonlinear eigenvalue equations. The amplitude-frequency relations for convergence with gridwork refinement, triangular plates, different boundary conditions, lamination angles, number of plies, and uniform versus concentrated loads are presented.

Nonlinear vibrations of thin arbitrarily laminated composite plates subjected to harmonic excitations using DKT elements

NASA Technical Reports Server (NTRS)

Chiang, C. K.; Xue, David Y.; Mei, Chuh

1993-01-01

A finite element formulation is presented for determining the large-amplitude free and steady-state forced vibration response of arbitrarily laminated anisotropic composite thin plates using the Discrete Kirchhoff Theory (DKT) triangular elements. The nonlinear stiffness and harmonic force matrices of an arbitrarily laminated composite triangular plate element are developed for nonlinear free and forced vibration analyses. The linearized updated-mode method with nonlinear time function approximation is employed for the solution of the system nonlinear eigenvalue equations. The amplitude-frequency relations for convergence with gridwork refinement, triangular plates, different boundary conditions, lamination angles, number of plies, and uniform versus concentrated loads are presented.

Genome-Wide Identification of Regulatory Elements and Reconstruction of Gene Regulatory Networks of the Green Alga Chlamydomonas reinhardtii under Carbon Deprivation

PubMed Central

Vischi Winck, Flavia; Arvidsson, Samuel; Riaño-Pachón, Diego Mauricio; Hempel, Sabrina; Koseska, Aneta; Nikoloski, Zoran; Urbina Gomez, David Alejandro; Rupprecht, Jens; Mueller-Roeber, Bernd

2013-01-01

The unicellular green alga Chlamydomonas reinhardtii is a long-established model organism for studies on photosynthesis and carbon metabolism-related physiology. Under conditions of air-level carbon dioxide concentration [CO2], a carbon concentrating mechanism (CCM) is induced to facilitate cellular carbon uptake. CCM increases the availability of carbon dioxide at the site of cellular carbon fixation. To improve our understanding of the transcriptional control of the CCM, we employed FAIRE-seq (formaldehyde-assisted Isolation of Regulatory Elements, followed by deep sequencing) to determine nucleosome-depleted chromatin regions of algal cells subjected to carbon deprivation. Our FAIRE data recapitulated the positions of known regulatory elements in the promoter of the periplasmic carbonic anhydrase (Cah1) gene, which is upregulated during CCM induction, and revealed new candidate regulatory elements at a genome-wide scale. In addition, time series expression patterns of 130 transcription factor (TF) and transcription regulator (TR) genes were obtained for cells cultured under photoautotrophic condition and subjected to a shift from high to low [CO2]. Groups of co-expressed genes were identified and a putative directed gene-regulatory network underlying the CCM was reconstructed from the gene expression data using the recently developed IOTA (inner composition alignment) method. Among the candidate regulatory genes, two members of the MYB-related TF family, Lcr1 (Low-CO 2 response regulator 1) and Lcr2 (Low-CO 2 response regulator 2), may play an important role in down-regulating the expression of a particular set of TF and TR genes in response to low [CO2]. The results obtained provide new insights into the transcriptional control of the CCM and revealed more than 60 new candidate regulatory genes. Deep sequencing of nucleosome-depleted genomic regions indicated the presence of new, previously unknown regulatory elements in the C. reinhardtii genome. Our work can serve as a basis for future functional studies of transcriptional regulator genes and genomic regulatory elements in Chlamydomonas. PMID:24224019

Comparison of partial least squares and lasso regression techniques as applied to laser-induced breakdown spectroscopy of geological samples

NASA Astrophysics Data System (ADS)

Dyar, M. D.; Carmosino, M. L.; Breves, E. A.; Ozanne, M. V.; Clegg, S. M.; Wiens, R. C.

2012-04-01

A remote laser-induced breakdown spectrometer (LIBS) designed to simulate the ChemCam instrument on the Mars Science Laboratory Rover Curiosity was used to probe 100 geologic samples at a 9-m standoff distance. ChemCam consists of an integrated remote LIBS instrument that will probe samples up to 7 m from the mast of the rover and a remote micro-imager (RMI) that will record context images. The elemental compositions of 100 igneous and highly-metamorphosed rocks are determined with LIBS using three variations of multivariate analysis, with a goal of improving the analytical accuracy. Two forms of partial least squares (PLS) regression are employed with finely-tuned parameters: PLS-1 regresses a single response variable (elemental concentration) against the observation variables (spectra, or intensity at each of 6144 spectrometer channels), while PLS-2 simultaneously regresses multiple response variables (concentrations of the ten major elements in rocks) against the observation predictor variables, taking advantage of natural correlations between elements. Those results are contrasted with those from the multivariate regression technique of the least absolute shrinkage and selection operator (lasso), which is a penalized shrunken regression method that selects the specific channels for each element that explain the most variance in the concentration of that element. To make this comparison, we use results of cross-validation and of held-out testing, and employ unscaled and uncentered spectral intensity data because all of the input variables are already in the same units. Results demonstrate that the lasso, PLS-1, and PLS-2 all yield comparable results in terms of accuracy for this dataset. However, the interpretability of these methods differs greatly in terms of fundamental understanding of LIBS emissions. PLS techniques generate principal components, linear combinations of intensities at any number of spectrometer channels, which explain as much variance in the response variables as possible while avoiding multicollinearity between principal components. When the selected number of principal components is projected back into the original feature space of the spectra, 6144 correlation coefficients are generated, a small fraction of which are mathematically significant to the regression. In contrast, the lasso models require only a small number (< 24) of non-zero correlation coefficients (β values) to determine the concentration of each of the ten major elements. Causality between the positively-correlated emission lines chosen by the lasso and the elemental concentration was examined. In general, the higher the lasso coefficient (β), the greater the likelihood that the selected line results from an emission of that element. Emission lines with negative β values should arise from elements that are anti-correlated with the element being predicted. For elements except Fe, Al, Ti, and P, the lasso-selected wavelength with the highest β value corresponds to the element being predicted, e.g. 559.8 nm for neutral Ca. However, the specific lines chosen by the lasso with positive β values are not always those from the element being predicted. Other wavelengths and the elements that most strongly correlate with them to predict concentration are obviously related to known geochemical correlations or close overlap of emission lines, while others must result from matrix effects. Use of the lasso technique thus directly informs our understanding of the underlying physical processes that give rise to LIBS emissions by determining which lines can best represent concentration, and which lines from other elements are causing matrix effects.

Development of finite element models to predict dynamic bridge response.

DOT National Transportation Integrated Search

1997-10-01

Dynamic response has long been recognized as one of the significant factors affecting the service life and safety of bridge structures. Even though considerable research, both analytical and experimental, has been devoted to dynamic bridge behavior, ...

29 CFR 1960.39 - Agency responsibilities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) BASIC PROGRAM ELEMENTS FOR FEDERAL EMPLOYEE OCCUPATIONAL SAFETY AND HEALTH PROGRAMS AND RELATED MATTERS Occupational Safety and Health Committees § 1960.39 Agency responsibilities. (a) Agencies shall...

29 CFR 1960.39 - Agency responsibilities.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) BASIC PROGRAM ELEMENTS FOR FEDERAL EMPLOYEE OCCUPATIONAL SAFETY AND HEALTH PROGRAMS AND RELATED MATTERS Occupational Safety and Health Committees § 1960.39 Agency responsibilities. (a) Agencies shall...

29 CFR 1960.39 - Agency responsibilities.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) BASIC PROGRAM ELEMENTS FOR FEDERAL EMPLOYEE OCCUPATIONAL SAFETY AND HEALTH PROGRAMS AND RELATED MATTERS Occupational Safety and Health Committees § 1960.39 Agency responsibilities. (a) Agencies shall...

Plant-soil distribution of potentially toxic elements in response to elevated atmospheric CO2.

PubMed

Duval, Benjamin D; Dijkstra, Paul; Natali, Susan M; Megonigal, J Patrick; Ketterer, Michael E; Drake, Bert G; Lerdau, Manuel T; Gordon, Gwyneth; Anbar, Ariel D; Hungate, Bruce A

2011-04-01

The distribution of contaminant elements within ecosystems is an environmental concern because of these elements' potential toxicity to animals and plants and their ability to hinder microbial ecosystem services. As with nutrients, contaminants are cycled within and through ecosystems. Elevated atmospheric CO2 generally increases plant productivity and alters nutrient element cycling, but whether CO2 causes similar effects on the cycling of contaminant elements is unknown. Here we show that 11 years of experimental CO2 enrichment in a sandy soil with low organic matter content causes plants to accumulate contaminants in plant biomass, with declines in the extractable contaminant element pools in surface soils. These results indicate that CO2 alters the distribution of contaminant elements in ecosystems, with plant element accumulation and declining soil availability both likely explained by the CO2 stimulation of plant biomass. Our results highlight the interdependence of element cycles and the importance of taking a broad view of the periodic table when the effects of global environmental change on ecosystem biogeochemistry are considered.

Coherence resonance and stochastic resonance in directionally coupled rings

NASA Astrophysics Data System (ADS)

Werner, Johannes Peter; Benner, Hartmut; Florio, Brendan James; Stemler, Thomas

2011-11-01

In coupled systems, symmetry plays an important role for the collective dynamics. We investigate the dynamical response to noise with and without weak periodic modulation for two classes of ring systems. Each ring system consists of unidirectionally coupled bistable elements but in one class, the number of elements is even while in the other class the number is odd. Consequently, the rings without forcing show at a certain coupling strength, either ordering (similar to anti-ferromagnetic chains) or auto-oscillations. Analysing the bifurcations and fixed points of the two ring classes enables us to explain the dynamical response measured to noise and weak modulation. Moreover, by analysing a simplified model, we demonstrate that the response is universal for systems having a directional component in their stochastic dynamics in phase space around the origin.

How to predict community responses to perturbations in the face of imperfect knowledge and network complexity

USGS Publications Warehouse

Aufderheide, Helge; Rudolf, Lars; Gross, Thilo; Lafferty, Kevin D.

2013-01-01

Recent attempts to predict the response of large food webs to perturbations have revealed that in larger systems increasingly precise information on the elements of the system is required. Thus, the effort needed for good predictions grows quickly with the system's complexity. Here, we show that not all elements need to be measured equally well, suggesting that a more efficient allocation of effort is possible. We develop an iterative technique for determining an efficient measurement strategy. In model food webs, we find that it is most important to precisely measure the mortality and predation rates of long-lived, generalist, top predators. Prioritizing the study of such species will make it easier to understand the response of complex food webs to perturbations.

The orphan receptor ERRα interferes with steroid signaling

PubMed Central

Teyssier, Catherine; Bianco, Stéphanie; Lanvin, Olivia; Vanacker, Jean-Marc

2008-01-01

The estrogen receptor-related receptor α (ERRα) is an orphan member of the nuclear receptor superfamily that has been shown to interfere with the estrogen-signaling pathway. In this report, we demonstrate that ERRα also cross-talks with signaling driven by other steroid hormones. Treatment of human prostatic cells with a specific ERRα inverse agonist reduces the expression of several androgen-responsive genes, in a manner that does not involve perturbation of androgen receptor expression or activity. Furthermore, ERRα activates the expression of androgen response elements (ARE)-containing promoters, such as that of the prostate cancer marker PSA, in an ARE-dependent manner. In addition, promoters containing a steroid response element can be activated by all members of the ERR orphan receptor subfamily, and this, even in the presence of antisteroid compounds. PMID:18697814

Microstructure-based hyperelastic models for closed-cell solids

PubMed Central

Wyatt, Hayley

2017-01-01

For cellular bodies involving large elastic deformations, mesoscopic continuum models that take into account the interplay between the geometry and the microstructural responses of the constituents are developed, analysed and compared with finite-element simulations of cellular structures with different architecture. For these models, constitutive restrictions for the physical plausibility of the material responses are established, and global descriptors such as nonlinear elastic and shear moduli and Poisson’s ratio are obtained from the material characteristics of the constituents. Numerical results show that these models capture well the mechanical responses of finite-element simulations for three-dimensional periodic structures of neo-Hookean material with closed cells under large tension. In particular, the mesoscopic models predict the macroscopic stiffening of the structure when the stiffness of the cell-core increases. PMID:28484340

Microstructure-based hyperelastic models for closed-cell solids.

PubMed

Mihai, L Angela; Wyatt, Hayley; Goriely, Alain

2017-04-01

For cellular bodies involving large elastic deformations, mesoscopic continuum models that take into account the interplay between the geometry and the microstructural responses of the constituents are developed, analysed and compared with finite-element simulations of cellular structures with different architecture. For these models, constitutive restrictions for the physical plausibility of the material responses are established, and global descriptors such as nonlinear elastic and shear moduli and Poisson's ratio are obtained from the material characteristics of the constituents. Numerical results show that these models capture well the mechanical responses of finite-element simulations for three-dimensional periodic structures of neo-Hookean material with closed cells under large tension. In particular, the mesoscopic models predict the macroscopic stiffening of the structure when the stiffness of the cell-core increases.

Microstructure-based hyperelastic models for closed-cell solids

NASA Astrophysics Data System (ADS)

Mihai, L. Angela; Wyatt, Hayley; Goriely, Alain

2017-04-01

For cellular bodies involving large elastic deformations, mesoscopic continuum models that take into account the interplay between the geometry and the microstructural responses of the constituents are developed, analysed and compared with finite-element simulations of cellular structures with different architecture. For these models, constitutive restrictions for the physical plausibility of the material responses are established, and global descriptors such as nonlinear elastic and shear moduli and Poisson's ratio are obtained from the material characteristics of the constituents. Numerical results show that these models capture well the mechanical responses of finite-element simulations for three-dimensional periodic structures of neo-Hookean material with closed cells under large tension. In particular, the mesoscopic models predict the macroscopic stiffening of the structure when the stiffness of the cell-core increases.

Linearity in the response of photopolymers as optical recording media.

PubMed

Gallego, Sergi; Marquez, Andrés; Guardiola, Francisco J; Riquelme, Marina; Fernández, Roberto; Pascual, Inmaculada; Beléndez, Augusto

2013-05-06

Photopolymer are appealing materials for diffractive elements recording. Two of their properties when they are illuminated are useful for this goal: the relief surface changes and the refractive index modifications. To this goal the linearity in the material response is crucial to design the optimum irradiance for each element. In this paper we measured directly some parameters to know how linear is the material response, in terms of the refractive index modulation versus exposure, then we can predict the refractive index distributions during recording. We have analyzed at different recording intensities the evolution of monomer diffusion during recording for photopolymers based on PVA/Acrylamide. This model has been successfully applied to PVA/Acrylamide photopolymers to predict the transmitted diffracted orders and the agreement with experimental values has been increased.

Finite element thermal analysis of multispectral coatings for the ABL

NASA Astrophysics Data System (ADS)

Shah, Rashmi S.; Bettis, Jerry R.; Stewart, Alan F.; Bonsall, Lynn; Copland, James; Hughes, William; Echeverry, Juan C.

1999-04-01

The thermal response of a coated optical surface is an important consideration in the design of any high average power system. Finite element temperature distribution were calculated for both coating witness samples and calorimetry wafers and were compared to actual measured data under tightly controlled conditions. Coatings for ABL were deposited on various substrates including fused silica, ULE, Zerodur, and silicon. The witness samples were irradiate data high power levels at 1.315micrometers to evaluate laser damage thresholds and study absorption levels. Excellent agreement was obtained between temperature predictions and measured thermal response curves. When measured absorption values were not available, the code was used to predict coating absorption based on the measured temperature rise on the back surface. Using the finite element model, the damaging temperature rise can be predicted for a coating with known absorption based on run time, flux, and substrate material.

Performance Requirements for Emergency Responder Interoperable and Compatible Electronic Safety Equipment

NASA Technical Reports Server (NTRS)

Greenberg, Paul S.

2012-01-01

Firefighters and other emergency response personnel are presented with an increasing array of technologies to improve their health and safety. This includes real-time bidirectional communication, navigation and positional information, data on physiological and metabolic functions, as well as data on their surrounding environment. The emerging challenge is to integrate these elements into a practical system, addressing such features as power, data transfer, and inter-element coordination and communication. In many respects, NASA has addressed these aspects in the context of Extra Vehicular Activity (EVA). The EVA environment shares many common attributes with that of emergency response scenarios. A similar situation exists in terms of the need for interoperability among the various system sub-elements. A brief overview is presented on the similarities and differences in these two applications, as well as the technical approach adopted by NASA in terms of system design philosophy.

STARS: An integrated general-purpose finite element structural, aeroelastic, and aeroservoelastic analysis computer program

NASA Technical Reports Server (NTRS)

Gupta, Kajal K.

1991-01-01

The details of an integrated general-purpose finite element structural analysis computer program which is also capable of solving complex multidisciplinary problems is presented. Thus, the SOLIDS module of the program possesses an extensive finite element library suitable for modeling most practical problems and is capable of solving statics, vibration, buckling, and dynamic response problems of complex structures, including spinning ones. The aerodynamic module, AERO, enables computation of unsteady aerodynamic forces for both subsonic and supersonic flow for subsequent flutter and divergence analysis of the structure. The associated aeroservoelastic analysis module, ASE, effects aero-structural-control stability analysis yielding frequency responses as well as damping characteristics of the structure. The program is written in standard FORTRAN to run on a wide variety of computers. Extensive graphics, preprocessing, and postprocessing routines are also available pertaining to a number of terminals.

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

NASA Astrophysics Data System (ADS)

Szafran, J.; Kamiński, M.

2017-02-01

The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Specificity determinants for the abscisic acid response element.

PubMed

Sarkar, Aditya Kumar; Lahiri, Ansuman

2013-01-01

Abscisic acid (ABA) response elements (ABREs) are a group of cis-acting DNA elements that have been identified from promoter analysis of many ABA-regulated genes in plants. We are interested in understanding the mechanism of binding specificity between ABREs and a class of bZIP transcription factors known as ABRE binding factors (ABFs). In this work, we have modeled the homodimeric structure of the bZIP domain of ABRE binding factor 1 from Arabidopsis thaliana (AtABF1) and studied its interaction with ACGT core motif-containing ABRE sequences. We have also examined the variation in the stability of the protein-DNA complex upon mutating ABRE sequences using the protein design algorithm FoldX. The high throughput free energy calculations successfully predicted the ability of ABF1 to bind to alternative core motifs like GCGT or AAGT and also rationalized the role of the flanking sequences in determining the specificity of the protein-DNA interaction.

Divergence of Drosophila melanogaster repeatomes in response to a sharp microclimate contrast in Evolution Canyon, Israel

PubMed Central

Kim, Young Bun; Oh, Jung Hun; McIver, Lauren J.; Rashkovetsky, Eugenia; Michalak, Katarzyna; Garner, Harold R.; Kang, Lin; Nevo, Eviatar; Korol, Abraham B.; Michalak, Pawel

2014-01-01

Repeat sequences, especially mobile elements, make up large portions of most eukaryotic genomes and provide enormous, albeit commonly underappreciated, evolutionary potential. We analyzed repeatomes of Drosophila melanogaster that have been diverging in response to a microclimate contrast in Evolution Canyon (Mount Carmel, Israel), a natural evolutionary laboratory with two abutting slopes at an average distance of only 200 m, which pose a constant ecological challenge to their local biotas. Flies inhabiting the colder and more humid north-facing slope carried about 6% more transposable elements than those from the hot and dry south-facing slope, in parallel to a suite of other genetic and phenotypic differences between the two populations. Nearly 50% of all mobile element insertions were slope unique, with many of them disrupting coding sequences of genes critical for cognition, olfaction, and thermotolerance, consistent with the observed patterns of thermotolerance differences and assortative mating. PMID:25006263

Divergence of Drosophila melanogaster repeatomes in response to a sharp microclimate contrast in Evolution Canyon, Israel.

PubMed

Kim, Young Bun; Oh, Jung Hun; McIver, Lauren J; Rashkovetsky, Eugenia; Michalak, Katarzyna; Garner, Harold R; Kang, Lin; Nevo, Eviatar; Korol, Abraham B; Michalak, Pawel

2014-07-22

Repeat sequences, especially mobile elements, make up large portions of most eukaryotic genomes and provide enormous, albeit commonly underappreciated, evolutionary potential. We analyzed repeatomes of Drosophila melanogaster that have been diverging in response to a microclimate contrast in Evolution Canyon (Mount Carmel, Israel), a natural evolutionary laboratory with two abutting slopes at an average distance of only 200 m, which pose a constant ecological challenge to their local biotas. Flies inhabiting the colder and more humid north-facing slope carried about 6% more transposable elements than those from the hot and dry south-facing slope, in parallel to a suite of other genetic and phenotypic differences between the two populations. Nearly 50% of all mobile element insertions were slope unique, with many of them disrupting coding sequences of genes critical for cognition, olfaction, and thermotolerance, consistent with the observed patterns of thermotolerance differences and assortative mating.

In-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in bearing steels

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

Voothaluru, Rohit; Bedekar, Vikram; Xie, Qingge

This work integrates in-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in high carbon bearing steels. The presence of a kinematically metastable retained austenite in bearing steels can significantly affect the macro-mechanical and micro-mechanical material response. Mechanical characterization of metastable austenite is a critical component in accurately capturing the micro-mechanical behavior under typical application loads. Traditional mechanical characterization techniques are unable to discretely quantify the micro-mechanical response of the austenite, and as a result, the computational predictions rely heavily on trial and error or qualitative descriptions of the austenite phase. Inmore » order to overcome this, in the present work, we use in-situ neutron diffraction of a uniaxial tension test of an A485 Grade 1 bearing steel specimen. The mechanical response determined from the neutron diffraction analysis was incorporated into a hybrid crystal plasticity finite element model that accounts for the martensite's crystal plasticity and the stress-assisted transformation from austenite to martensite in bearing steels. Here, the modeling response was used to estimate the single crystal elastic constants of the austenite and martensite phases. Finally, the results show that using in-situ neutron diffraction, coupled with a crystal plasticity model, can successfully predict both the micro-mechanical and macro-mechanical responses of bearing steels while accounting for the martensitic transformation of the retained austenite.« less

Abiotic Stress Response to As and As+Si, Composite Reprogramming of Fruit Metabolites in Tomato Cultivars

PubMed Central

Marmiroli, Marta; Mussi, Francesca; Imperiale, Davide; Lencioni, Giacomo; Marmiroli, Nelson

2017-01-01

The toxic element arsenic interacts with the beneficial element silicon at many levels of the plant metabolism. The ability of the tomato plant to take up and translocate As into its fruit has risen concerns that it could facilitate the entry of this element into the human food chain above the admitted level. Here, the fruit of two contrasting tomato cultivars, Aragon and Gladis, were evaluated following exposures of either 48 h or 14 days to As-contaminated irrigation water, with or without supplementary Si. The focus was on selected biochemical stress response indicators to dissect metabolic fruit reprogramming induced by As and Si. A multivariate statistical approach was utilized to establish the relationship between tissue As and Si concentrations and selected biochemical aspects of the stress response mechanisms to identify a set of relevant stress response descriptors. This resulted in the recognition of strong cultivar and temporal effects on metabolic and biochemical stress parameters following the treatments. In this paper the metabolic changes in H2O2 content, lipid peroxidation, lycopene and carotenoids content, ascorbate and GSH redox state, total phenolics, ABTS and DPPH radicals inhibition were in favor of an oxidative stress. The significance of some of these parameters as reliable arsenic exposition biomarkers is discussed in the context of the limited knowledge on the As-induced stress response mechanisms at the level of the ripening fruit which presents a distinctive molecular background dissimilar from roots and shoots. PMID:29312426

Transcriptional activation of transforming growth factor alpha by estradiol: requirement for both a GC-rich site and an estrogen response element half-site.

PubMed

Vyhlidal, C; Samudio, I; Kladde, M P; Safe, S

2000-06-01

17beta-Estradiol (E2) induces transforming growth factor alpha (TGFalpha) gene expression in MCF-7 cells and previous studies have identified a 53 bp (-252 to -200) sequence containing two imperfect estrogen responsive elements (EREs) that contribute to E2 responsiveness. Deletion analysis of the TGFalpha gene promoter in this study identified a second upstream region of the promoter (-623 to -549) that is also E2 responsive. This sequence contains three GC-rich sites and an imperfect ERE half-site, and the specific cis-elements and trans-acting factors were determined by promoter analysis in transient transfection experiments, gel mobility shift assays and in vitro DNA footprinting. The results are consistent with an estrogen receptor alpha (ERalpha)/Sp1 complex interacting with an Sp1(N)(30) ERE half-site ((1/2)) motif in which both ERalpha and Sp1 bind promoter DNA. The ER/Sp1-DNA complex is formed using nuclear extracts from MCF-7 cells but not with recombinant human ERalpha or Sp1 proteins, suggesting that other nuclear factor(s) are required for complex stabilization. The E2-responsive Sp1(N)(x)ERE(1/2) motif identified in the TGFalpha gene promoter has also been characterized in the cathepsin D and heat shock protein 27 gene promoters; however, in the latter two promoters the numbers of intervening nucleotides are 23 and 10 respectively.

In-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in bearing steels

DOE PAGES

Voothaluru, Rohit; Bedekar, Vikram; Xie, Qingge; ...

2018-11-21

This work integrates in-situ neutron diffraction and crystal plasticity finite element modeling to study the kinematic stability of retained austenite in high carbon bearing steels. The presence of a kinematically metastable retained austenite in bearing steels can significantly affect the macro-mechanical and micro-mechanical material response. Mechanical characterization of metastable austenite is a critical component in accurately capturing the micro-mechanical behavior under typical application loads. Traditional mechanical characterization techniques are unable to discretely quantify the micro-mechanical response of the austenite, and as a result, the computational predictions rely heavily on trial and error or qualitative descriptions of the austenite phase. Inmore » order to overcome this, in the present work, we use in-situ neutron diffraction of a uniaxial tension test of an A485 Grade 1 bearing steel specimen. The mechanical response determined from the neutron diffraction analysis was incorporated into a hybrid crystal plasticity finite element model that accounts for the martensite's crystal plasticity and the stress-assisted transformation from austenite to martensite in bearing steels. Here, the modeling response was used to estimate the single crystal elastic constants of the austenite and martensite phases. Finally, the results show that using in-situ neutron diffraction, coupled with a crystal plasticity model, can successfully predict both the micro-mechanical and macro-mechanical responses of bearing steels while accounting for the martensitic transformation of the retained austenite.« less

Stat5-mediated regulation of the human type II 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase gene: activation by prolactin.

PubMed

Feltus, F A; Groner, B; Melner, M H

1999-07-01

Altered PRL levels are associated with infertility in women. Molecular targets at which PRL elicits these effects have yet to be determined. These studies demonstrate transcriptional regulation by PRL of the gene encoding the final enzymatic step in progesterone biosynthesis: 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase (3beta-HSD). A 9/9 match with the consensus Stat5 response element was identified at -110 to -118 in the human Type II 3beta-HSD promoter. 3beta-HSD chloramphenicol acetyltransferase (CAT) reporter constructs containing either an intact or mutated Stat5 element were tested for PRL activation. Expression vectors for Stat5 and the PRL receptor were cotransfected with a -300 --> +45 3beta-HSD CAT reporter construct into HeLa cells, which resulted in a 21-fold increase in reporter activity in the presence of PRL. Promoter activity showed an increased response with a stepwise elevation of transfected Stat5 expression or by treatment with increasing concentrations of PRL (max, 250 ng/ml). This effect was dramatically reduced when the putative Stat5 response element was removed by 5'-deletion of the promoter or by the introduction of a 3-bp mutation into critical nucleotides in the element. Furthermore, 32P-labeled promoter fragments containing the Stat5 element were shifted in electrophoretic mobility shift assay experiments using nuclear extracts from cells treated with PRL, and this complex was supershifted with antibodies to Stat5. These results demonstrate that PRL has the ability to regulate expression of a key human enzyme gene (type II 3beta-HSD) in the progesterone biosynthetic pathway, which is essential for maintaining pregnancy.

Pathogen Phytosensing: Plants to Report Plant Pathogens.

PubMed

Mazarei, Mitra; Teplova, Irina; Hajimorad, M Reza; Stewart, C Neal

2008-04-14

Real-time systems that provide evidence of pathogen contamination in crops can be an important new line of early defense in agricultural centers. Plants possess defense mechanisms to protect against pathogen attack. Inducible plant defense is controlled by signal transduction pathways, inducible promoters and cis-regulatory elements corresponding to key genes involved in defense, and pathogen-specific responses. Identified inducible promoters and cis-acting elements could be utilized in plant sentinels, or 'phytosensors', by fusing these to reporter genes to produce plants with altered phenotypes in response to the presence of pathogens. Here, we have employed cis-acting elements from promoter regions of pathogen inducible genes as well as those responsive to the plant defense signal molecules salicylic acid, jasmonic acid, and ethylene. Synthetic promoters were constructed by combining various regulatory elements supplemented with the enhancer elements from the Cauliflower mosaic virus (CaMV) 35S promoter to increase basal level of the GUS expression. The inducibility of each synthetic promoter was first assessed in transient expression assays using Arabidopsis thaliana protoplasts and then examined for efficacy in stably transgenic Arabidopsis and tobacco plants. Histochemical and fluorometric GUS expression analyses showed that both transgenic Arabidopsis and tobacco plants responded to elicitor and phytohormone treatments with increased GUS expression when compared to untreated plants. Pathogen-inducible phytosensor studies were initiated by analyzing the sensitivity of the synthetic promoters against virus infection. Transgenic tobacco plants infected with Alfalfa mosaic virus showed an increase in GUS expression when compared to mock-inoculated control plants, whereas Tobacco mosaic virus infection caused no changes in GUS expression. Further research, using these transgenic plants against a range of different pathogens with the regulation of detectable reporter gene could provide biological evidence to define the functional differences between pathogens, and provide new technology and applications for transgenic plants as phytosensors.

Vibration analyses of an inclined flat plate subjected to moving loads

NASA Astrophysics Data System (ADS)

Wu, Jia-Jang

2007-01-01

The object of this paper is to present a moving mass element so that one may easily perform the dynamic analysis of an inclined plate subjected to moving loads with the effects of inertia force, Coriolis force and centrifugal force considered. To this end, the mass, damping and stiffness matrices of the moving mass element, with respect to the local coordinate system, are derived first by using the principle of superposition and the definition of shape functions. Next, the last property matrices of the moving mass element are transformed into the global coordinate system and combined with the property matrices of the inclined plate itself to determine the effective overall property matrices and the instantaneous equations of motion of the entire vibrating system. Because the property matrices of the moving mass element have something to do with the instantaneous position of the moving load, both the property matrices of the moving mass element and the effective overall ones of the entire vibrating system are time-dependent. At any instant of time, solving the instantaneous equations of motion yields the instantaneous dynamic responses of the inclined plate. For validation, the presented technique is used to determine the dynamic responses of a horizontal pinned-pinned plate subjected to a moving load and a satisfactory agreement with the existing literature is achieved. Furthermore, extensive studies on the inclined plate subjected to moving loads reveal that the influences of moving-load speed, inclined angle of the plate and total number of the moving loads on the dynamic responses of the inclined plate are significant in most cases, and the effects of Coriolis force and centrifugal force are perceptible only in the case of higher moving-load speed.

Assessment of biotic response to heavy metal contamination in Avicennia marina mangrove ecosystems in Sydney Estuary, Australia.

PubMed

Nath, Bibhash; Chaudhuri, Punarbasu; Birch, Gavin

2014-09-01

Mangrove forests act as a natural filter of land-derived wastewaters along industrialized tropical and sub-tropical coastlines and assist in maintaining a healthy living condition for marine ecosystems. Currently, these intertidal communities are under serious threat from heavy metal contamination induced by human activity associated with rapid urbanization and industrialization. Studies on the biotic responses of these plants to heavy metal contamination are of great significance in estuary management and maintaining coastal ecosystem health. The main objective of the present investigation was to assess the biotic response in Avicennia marina ecosystems to heavy metal contamination through the determination of metal concentrations in leaves, fine nutritive roots and underlying sediments collected in fifteen locations across Sydney Estuary (Australia). Metal concentrations (especially Cu, Pb and Zn) in the underlying sediments of A. marina were enriched to a level (based on Interim Sediment Quality Guidelines) at which adverse biological effects to flora could occasionally occur. Metals accumulated in fine nutritive roots greater than underlying sediments, however, only minor translocation of these metals to A. marina leaves was observed (mean translocation factors, TFs, for all elements <0.13, except for Mn). Translocation factors of essential elements (i.e., common plant micro-nutrients, Cu, Ni, Mn and Zn) were greater than non-essential elements (As, Cd, Co, Cr and Pb), suggesting that A. marina mangroves of this estuary selectively excluded non-essential elements, while regulating essential elements and limiting toxicity to plants. This study supports the notion that A. marina mangroves act as a phytostabilizer in this highly modified estuary thereby protecting the aquatic ecosystem from point or non-point sources of heavy metal contamination. Copyright © 2014 Elsevier Inc. All rights reserved.

Finite-Element Methods for Real-Time Simulation of Surgery

NASA Technical Reports Server (NTRS)

Basdogan, Cagatay

2003-01-01

Two finite-element methods have been developed for mathematical modeling of the time-dependent behaviors of deformable objects and, more specifically, the mechanical responses of soft tissues and organs in contact with surgical tools. These methods may afford the computational efficiency needed to satisfy the requirement to obtain computational results in real time for simulating surgical procedures as described in Simulation System for Training in Laparoscopic Surgery (NPO-21192) on page 31 in this issue of NASA Tech Briefs. Simulation of the behavior of soft tissue in real time is a challenging problem because of the complexity of soft-tissue mechanics. The responses of soft tissues are characterized by nonlinearities and by spatial inhomogeneities and rate and time dependences of material properties. Finite-element methods seem promising for integrating these characteristics of tissues into computational models of organs, but they demand much central-processing-unit (CPU) time and memory, and the demand increases with the number of nodes and degrees of freedom in a given finite-element model. Hence, as finite-element models become more realistic, it becomes more difficult to compute solutions in real time. In both of the present methods, one uses approximate mathematical models trading some accuracy for computational efficiency and thereby increasing the feasibility of attaining real-time up36 NASA Tech Briefs, October 2003 date rates. The first of these methods is based on modal analysis. In this method, one reduces the number of differential equations by selecting only the most significant vibration modes of an object (typically, a suitable number of the lowest-frequency modes) for computing deformations of the object in response to applied forces.

Transitions: Managing the Transfer of Security Responsibility

DTIC Science & Technology

2010-02-05

Index 1.2_Transitions-ConceptNote_v2.0_draft Index Transitions: Managing the Transfer of Security Responsibility A Concept Paper...reporting burden for the collection of information is estimated to average 1 hour per response , including the time for reviewing instructions...TITLE AND SUBTITLE Transitions: Managing the Transfer of Security Responsibility 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Free and forced vibrations of a tyre using a wave/finite element approach

NASA Astrophysics Data System (ADS)

Waki, Y.; Mace, B. R.; Brennan, M. J.

2009-06-01

Free and forced vibrations of a tyre are predicted using a wave/finite element (WFE) approach. A short circumferential segment of the tyre is modelled using conventional finite element (FE) methods, a periodicity condition applied and the mass and stiffness matrices post-processed to yield wave properties. Since conventional FE methods are used, commercial FE packages and existing element libraries can be utilised. An eigenvalue problem is formulated in terms of the transfer matrix of the segment. Zhong's method is used to improve numerical conditioning. The eigenvalues and eigenvectors give the wavenumbers and wave mode shapes, which in turn define transformations between the physical and wave domains. A method is described by which the frequency dependent material properties of the rubber components of the tyre can be included without the need to remesh the structure. Expressions for the forced response are developed which are numerically well-conditioned. Numerical results for a smooth tyre are presented. Dispersion curves for real, imaginary and complex wavenumbers are shown. The propagating waves are associated with various forms of motion of the tread supported by the stiffness of the side wall. Various dispersion phenomena are observed, including curve veering, non-zero cut-off and waves for which the phase velocity and the group velocity have opposite signs. Results for the forced response are compared with experimental measurements and good agreement is seen. The forced response is numerically determined for both finite area and point excitations. It is seen that the size of area of the excitation is particularly important at high frequencies. When the size of the excitation area is small enough compared to the tread thickness, the response at high frequencies becomes stiffness-like (reactive) and the effect of shear stiffness becomes important.

The human apolipoprotein AV gene is regulated by peroxisome proliferator-activated receptor-alpha and contains a novel farnesoid X-activated receptor response element.

PubMed

Prieur, Xavier; Coste, Herve; Rodriguez, Joan C

2003-07-11

The newly identified apolipoprotein AV (apoAV) gene is a key player in determining plasma triglyceride concentrations. Because hypertriglyceridemia is a major independent risk factor in coronary artery disease, the understanding of the regulation of the expression of this gene is of considerable importance. We presently characterize the structure, the transcription start site, and the promoter of the human apoAV gene. Since the peroxisome proliferator-activated receptor-alpha (PPARalpha) and the farnesoid X-activated receptor (FXR) have been shown to modulate the expression of genes involved in triglyceride metabolism, we evaluated the potential role of these nuclear receptors in the regulation of apoAV transcription. Bile acids and FXR induced the apoAV gene promoter activity. 5'-Deletion, mutagenesis, and gel shift analysis identified a heretofore unknown element at positions -103/-84 consisting of an inverted repeat of two consensus receptor-binding hexads separated by 8 nucleotides (IR8), which was required for the response to bile acid-activated FXR. The isolated IR8 element conferred FXR responsiveness on a heterologous promoter. On the other hand, in apoAV-expressing human hepatic Hep3B cells, transfection of PPARalpha specifically enhanced apoAV promoter activity. By deletion, site-directed mutagenesis, and binding analysis, a PPARalpha response element located 271 bp upstream of the transcription start site was identified. Finally, treatment with a specific PPARalpha activator led to a significant induction of apoAV mRNA expression in hepatocytes. The identification of apoAV as a PPARalpha target gene has major implications with respect to mechanisms whereby pharmacological PPARalpha agonists may exert their beneficial hypotriglyceridemic actions.

Thyroid Hormone Receptor β (TRβ) and Liver X Receptor (LXR) Regulate Carbohydrate-response Element-binding Protein (ChREBP) Expression in a Tissue-selective Manner*

PubMed Central

Gauthier, Karine; Billon, Cyrielle; Bissler, Marie; Beylot, Michel; Lobaccaro, Jean-Marc; Vanacker, Jean-Marc; Samarut, Jacques

2010-01-01

Thyroid hormone (TR) and liver X (LXR) receptors are transcription factors involved in lipogenesis. Both receptors recognize the same consensus DNA-response element in vitro. It was previously shown that their signaling pathways interact in the control of cholesterol elimination in the liver. In the present study, carbohydrate-response element-binding protein (ChREBP), a major transcription factor controlling the activation of glucose-induced lipogenesis in liver, is characterized as a direct target of thyroid hormones (TH) in liver and white adipose tissue (WAT), the two main lipogenic tissues in mice. Using genetic and molecular approaches, ChREBP is shown to be specifically regulated by TRβ but not by TRα in vivo, even in WAT where both TR isoforms are expressed. However, this isotype specificity is not found in vitro. This TRβ specific regulation correlates with the loss of TH-induced lipogenesis in TRβ−/− mice. Fasting/refeeding experiments show that TRβ is not required for the activation of ChREBP expression particularly marked in WAT following refeeding. However, TH can stimulate ChREBP expression in WAT even under fasting conditions, suggesting completely independent pathways. Because ChREBP has been described as an LXR target, the interaction of LXR and TRβ in ChREBP regulation was assayed both in vitro and in vivo. Each receptor recognizes a different response element on the ChREBP promoter, located only 8 bp apart. There is a cross-talk between LXR and TRβ signaling on the ChREBP promoter in liver but not in WAT where LXR does not regulate ChREBP expression. The molecular basis for this cross-talk has been determined in in vitro systems. PMID:20615868

Stimulation of interleukin-13 expression by human T-cell leukemia virus type 1 oncoprotein Tax via a dually active promoter element responsive to NF-kappaB and NFAT.

PubMed

Silbermann, Katrin; Schneider, Grit; Grassmann, Ralph

2008-11-01

The human T-cell leukemia virus type 1 (HTLV-1) Tax oncoprotein transforms human lymphocytes and is critical for the pathogenesis of HTLV-1-induced adult T-cell leukaemia. In HTLV-transformed cells, Tax upregulates interleukin (IL)-13, a cytokine with proliferative and anti-apoptotic functions that is linked to leukaemogenesis. Tax-stimulated IL-13 is thought to result in autocrine stimulation of HTLV-infected cells and thus may be relevant to their growth. The causal transactivation of the IL-13 promoter by Tax is predominantly dependent on a nuclear factor of activated T cells (NFAT)-binding P element. Here, it was shown that the isolated IL-13 Tax-responsive element (IL13TaxRE) was sufficient to mediate IL-13 transactivation by Tax and NFAT1. However, cyclosporin A, a specific NFAT inhibitor, revealed that Tax transactivation of IL13TaxRE or wild-type IL-13 promoter was independent of NFAT and that NFAT did not contribute to IL-13 upregulation in HTLV-transformed cells. By contrast, Tax stimulation was repressible by an efficient nuclear factor (NF)-kappaB inhibitor (IkBaDN), indicating the requirement for NF-kappaB. The capacity of NF-kappaB to stimulate IL13TaxRE was demonstrated by a strong response to NF-kappaB in reporter assays and by direct binding of NF-kappaB to IL13TaxRE. Thus, IL13TaxRE in the IL-13 promoter represents a dually active promoter element responsive to NF-kappaB and NFAT. Together, these results indicate that Tax causes IL-13 upregulation in HTLV-1-infected cells via NF-kappaB.

Defining competency-based evaluation objectives in family medicine

PubMed Central

Allen, Tim; Brailovsky, Carlos; Rainsberry, Paul; Lawrence, Katherine; Crichton, Tom; Carpentier, Marie-Pierre; Visser, Shaun

2011-01-01

Abstract Objective To develop a definition of competence in family medicine sufficient to guide a review of Certification examinations by the Board of Examiners of the College of Family Physicians of Canada. Design Delphi analysis of responses to a 4-question postal survey. Setting Canadian family practice. Participants A total of 302 family physicians who have served as examiners for the College of Family Physicians of Canada’s Certification examination. Methods A survey comprising 4 short-answer questions was mailed to the 302 participating family physicians asking them to list elements that define competence in family medicine among newly certified family physicians beginning independent practice. Two expert groups used a modified Delphi consensus process to analyze responses and generate 2 basic components of this definition of competence: first, the problems that a newly practising family physician should be competent to handle; second, the qualities, behaviour, and skills that characterize competence at the start of independent practice. Main findings Response rate was 54%; total number of elements among all responses was 5077, for an average 31 per respondent. Of the elements, 2676 were topics or clinical situations to be dealt with; the other 2401 were skills, behaviour patterns, or qualities, without reference to a specific clinical problem. The expert groups identified 6 essential skills, the phases of the clinical encounter, and 99 priority topics as the descriptors used by the respondents. More than 20% of respondents cited 30 of the topics. Conclusion Family physicians define the domain of competence in family medicine in terms of 6 essential skills, the phases of the clinical encounter, and priority topics. This survey represents the first level of definition of evaluation objectives in family medicine. Definition of the interactions among these elements will permit these objectives to become detailed enough to effectively guide assessment. PMID:21918130

Correlation of finite element free vibration predictions using random vibration test data. M.S. Thesis - Cleveland State Univ.

NASA Technical Reports Server (NTRS)

Chambers, Jeffrey A.

1994-01-01

Finite element analysis is regularly used during the engineering cycle of mechanical systems to predict the response to static, thermal, and dynamic loads. The finite element model (FEM) used to represent the system is often correlated with physical test results to determine the validity of analytical results provided. Results from dynamic testing provide one means for performing this correlation. One of the most common methods of measuring accuracy is by classical modal testing, whereby vibratory mode shapes are compared to mode shapes provided by finite element analysis. The degree of correlation between the test and analytical mode shapes can be shown mathematically using the cross orthogonality check. A great deal of time and effort can be exhausted in generating the set of test acquired mode shapes needed for the cross orthogonality check. In most situations response data from vibration tests are digitally processed to generate the mode shapes from a combination of modal parameters, forcing functions, and recorded response data. An alternate method is proposed in which the same correlation of analytical and test acquired mode shapes can be achieved without conducting the modal survey. Instead a procedure is detailed in which a minimum of test information, specifically the acceleration response data from a random vibration test, is used to generate a set of equivalent local accelerations to be applied to the reduced analytical model at discrete points corresponding to the test measurement locations. The static solution of the analytical model then produces a set of deformations that once normalized can be used to represent the test acquired mode shapes in the cross orthogonality relation. The method proposed has been shown to provide accurate results for both a simple analytical model as well as a complex space flight structure.

Fibroblast growth factor and cyclic AMP (cAMP) synergistically activate gene expression at a cAMP response element.

PubMed Central

Tan, Y; Low, K G; Boccia, C; Grossman, J; Comb, M J

1994-01-01

Growth factors and cyclic AMP (cAMP) are known to activate distinct intracellular signaling pathways. Fibroblast growth factor (FGF) activates ras-dependent kinase cascades, resulting in the activation of MAP kinases, whereas cAMP activates protein kinase A. In this study, we report that growth factors and cAMP act synergistically to stimulate proenkephalin gene expression. Positive synergy between growth factor- and cAMP-activated signaling pathways on gene expression has not been previously reported, and we suggest that these synergistic interactions represent a useful model for analyzing interactions between these pathways. Transfection and mutational studies indicate that both FGF-dependent gene activation and cAMP-dependent gene activation require cAMP response element 2 (CRE-2), a previously characterized cAMP-dependent regulatory element. Furthermore, multiple copies of this element are sufficient to confer FGF regulation upon a minimal promoter, indicating that FGF and cAMP signaling converge upon transcription factors acting at CRE-2. Among many different ATF/AP-1 factors tested, two factors, ATF-3 and c-Jun, stimulate proenkephalin transcription in an FGF- or Ras-dependent fashion. Finally, we show that ATF-3 and c-Jun form heterodimeric complexes in SK-N-MC cells and that the levels of both proteins are increased in response to FGF but not cAMP. Together, these results indicate that growth factor- and cAMP-dependent signaling pathways converge at CRE-2 to synergistically stimulate gene expression and that ATF-3 and c-Jun regulate proenkephalin transcription in response to both growth factor- and cAMP-dependent intracellular signaling pathways. Images PMID:7935470