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1

Protein-protein-interaction Network Organization of the Hypusine Modification System*  

PubMed Central

Hypusine modification of eukaryotic initiation factor 5A (eIF-5A) represents a unique and highly specific post-translational modification with regulatory functions in cancer, diabetes, and infectious diseases. However, the specific cellular pathways that are influenced by the hypusine modification remain largely unknown. To globally characterize eIF-5A and hypusine-dependent pathways, we used an approach that combines large-scale bioreactor cell culture with tandem affinity purification and mass spectrometry: “bioreactor-TAP-MS/MS.” By applying this approach systematically to all four components of the hypusine modification system (eIF-5A1, eIF-5A2, DHS, and DOHH), we identified 248 interacting proteins as components of the cellular hypusine network, with diverse functions including regulation of translation, mRNA processing, DNA replication, and cell cycle regulation. Network analysis of this data set enabled us to provide a comprehensive overview of the protein-protein interaction landscape of the hypusine modification system. In addition, we validated the interaction of eIF-5A with some of the newly identified associated proteins in more detail. Our analysis has revealed numerous novel interactions, and thus provides a valuable resource for understanding how this crucial homeostatic signaling pathway affects different cellular functions.

Sievert, Henning; Venz, Simone; Platas-Barradas, Oscar; Dhople, Vishnu M.; Schaletzky, Martin; Nagel, Claus-Henning; Braig, Melanie; Preukschas, Michael; Pallmann, Nora; Bokemeyer, Carsten; Brummendorf, Tim H.; Portner, Ralf; Walther, Reinhard; Duncan, Kent E.; Hauber, Joachim; Balabanov, Stefan

2012-01-01

2

Functional significance of eIF5A and its hypusine modification in eukaryotes  

PubMed Central

The unusual basic amino acid, hypusine [N?-(4-amino-2-hydroxybutyl)-lysine], is a modified lysine with the addition of the 4-aminobutyl moiety from the polyamine spermidine. This naturally occurring amino acid is a product of a unique posttranslational modification that occurs in only one cellular protein, eukaryotic translation initiation factor 5A (eIF5A, eIF-5A). Hypusine is synthesized exclusively in this protein by two sequential enzymatic steps involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). The deoxyhypusine/hypusine synthetic pathway has evolved in archaea and eukaryotes, and eIF5A, DHS and DOHH are highly conserved suggesting a vital cellular function of eIF5A. Gene disruption and mutation studies in yeast and higher eukaryotes have provided valuable information on the essential nature of eIF5A and the deoxyhypusine/hypusine modification in cell growth and in protein synthesis. In view of the extraordinary specificity and functional significance of hypusine-containing eIF5A in mammalian cell proliferation, eIF5A and the hypusine biosynthetic enzymes are novel potential targets for intervention in aberrant cell proliferation.

Park, M. H.; Nishimura, K.; Zanelli, C. F.; Valentini, S. R.

2010-01-01

3

The effect of hypusine modification on the intracellular localization of eIF5A  

PubMed Central

Eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein essential for eukaryotic cell proliferation and is the only protein containing hypusine, [N?-(4-amino-2-hydroxybutyl)lysine]. eIF5A is activated by the posttranslational synthesis of hypusine. eIF5A also undergoes an acetylation at specific Lys residue(s). In this study, we have investigated the effect of hypusine modification and acetylation on the subcellular localization of eIF5A. Immunocytochemical analyses showed differences in the distribution of non-hypusinated eIF5A precursor and the hypusine-containing mature eIF5A. While the precursor is found in both cytoplasm and nucleus, the hypusinated eIF5A is primarily localized in cytoplasm. eIF5A mutant proteins, defective in hypusine modification (K50A, K50R) were localized in a similar manner to the eIF5A precursor, whereas hypusine-modified mutant proteins (K47A, K47R, K68A) were localized mainly in the cytoplasm. These findings provide strong evidence that the hypusine modification of eIF5A dictates its localization in the cytoplasmic compartment where it is required for protein synthesis.

Lee, Seung Bum; Park, Jong Hwan; Kaevel, Jorn; Sramkova, Monika; Weigert, Roberto; Park, Myung Hee

2009-01-01

4

A Unique Modification of the Eukaryotic Initiation Factor 5A Shows the Presence of the Complete Hypusine Pathway in Leishmania donovani  

PubMed Central

Deoxyhypusine hydroxylase (DOHH) catalyzes the final step in the post-translational synthesis of an unusual amino acid hypusine (N€-(4-amino-2-hydroxybutyl) lysine), which is present on only one cellular protein, eukaryotic initiation factor 5A (eIF5A). We present here the molecular and structural basis of the function of DOHH from the protozoan parasite, Leishmania donovani, which causes visceral leishmaniasis. The L. donovani DOHH gene is 981 bp and encodes a putative polypeptide of 326 amino acids. DOHH is a HEAT-repeat protein with eight tandem repeats of ?-helical pairs. Four conserved histidine-glutamate sequences have been identified that may act as metal coordination sites. A ?42 kDa recombinant protein with a His-tag was obtained by heterologous expression of DOHH in Escherichia coli. Purified recombinant DOHH effectively catalyzed the hydroxylation of the intermediate, eIF5A-deoxyhypusine (eIF5A-Dhp), in vitro. L. donovani DOHH (LdDOHH) showed ?40.6% sequence identity with its human homolog. The alignment of L. donovani DOHH with the human homolog shows that there are two significant insertions in the former, corresponding to the alignment positions 159-162 (four amino acid residues) and 174-183 (ten amino acid residues) which are present in the variable loop connecting the N- and C-terminal halves of the protein, the latter being present near the substrate binding site. Deletion of the ten-amino-acid-long insertion decreased LdDOHH activity to 14% of the wild type recombinant LdDOHH. Metal chelators like ciclopirox olamine (CPX) and mimosine significantly inhibited the growth of L. donovani and DOHH activity in vitro. These inhibitors were more effective against the parasite enzyme than the human enzyme. This report, for the first time, confirms the presence of a complete hypusine pathway in a kinetoplastid unlike eubacteria and archaea. The structural differences between the L. donovani DOHH and the human homolog may be exploited for structure based design of selective inhibitors against the parasite.

Chawla, Bhavna; Kumar, Ravi Ranjan; Tyagi, Nidhi; Subramanian, Gowri; Srinivasan, N.; Park, Myung Hee; Madhubala, Rentala

2012-01-01

5

Production of active recombinant eIF5A: reconstitution in E.coli of eukaryotic hypusine modification of eIF5A by its coexpression with modifying enzymes  

PubMed Central

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N?-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation.

Park, Jong Hwan; Dias, Camila A. O.; Lee, Seung Bum; Valentini, Sandro R.; Sokabe, Masaaki; Fraser, Christopher S.; Park, Myung Hee

2011-01-01

6

The Post-Translational Synthesis of a Polyamine-Derived Amino Acid, Hypusine, in the Eukaryotic Translation Initiation Factor 5A (eIF5A)  

PubMed Central

The eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the unique polyamine-derived amino acid, hypusine [N?-(4-amino-2-hydroxybutyl) lysine]. Hypusine is formed in eIF5A by a novel post-translational modification reaction that involves two enzymatic steps. In the first step, deoxyhypusine synthase catalyzes the cleavage of the polyamine spermidine and transfer of its 4-aminobutyl moiety to the ?-amino group of one specific lysine residue of the eIF5A precursor to form a deoxyhypusine intermediate. In the second step, deoxyhypusine hydroxylase converts the deoxyhypusine-containing intermediate to the hypusine-containing mature eIF5A. The structure and mechanism of deoxyhypusine synthase have been extensively characterized. Deoxyhypusine hydroxylase is a HEAT-repeat protein with a symmetrical superhelical structure consisting of 8 helical hairpins (HEAT motifs). It is a novel metalloenzyme containing tightly bound iron at the active sites. Four strictly conserved His-Glu pairs were identified as iron coordination sites. The structural fold of deoxyhypusine hydroxylase is entirely different from those of the other known protein hydroxylases such as prolyl 4-hydroxylase and lysylhydroxylases. The eIF5A protein and deoxyhypusine/hypusine modification are essential for eukaryotic cell proliferation. Thus, hypusine synthesis represents the most specific protein modification known to date, and presents a novel target for intervention in mammalian cell proliferation.

Park, Myung Hee

2008-01-01

7

Biochemical quantitation of the eIF5A hypusination in Arabidopsis thaliana uncovers ABA-dependent regulation  

PubMed Central

The eukaryotic translation elongation factor eIF5A is the only protein known to contain the unusual amino acid hypusine which is essential for its biological activity. This post-translational modification is achieved by the sequential action of the enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). The crucial molecular function of eIF5A during translation has been recently elucidated in yeast and it is expected to be fully conserved in every eukaryotic cell, however the functional description of this pathway in plants is still sparse. The genetic approaches with transgenic plants for either eIF5A overexpression or antisense have revealed some activities related to the control of cell death processes but the molecular details remain to be characterized. One important aspect of fully understanding this pathway is the biochemical description of the hypusine modification system. Here we have used recombinant eIF5A proteins either modified by hypusination or non-modified to establish a bi-dimensional electrophoresis (2D-E) profile for the three eIF5A protein isoforms and their hypusinated or unmodified proteoforms present in Arabidopsis thaliana. The combined use of the recombinant 2D-E profile together with 2D-E/western blot analysis from whole plant extracts has provided a quantitative approach to measure the hypusination status of eIF5A. We have used this information to demonstrate that treatment with the hormone abscisic acid produces an alteration of the hypusine modification system in Arabidopsis thaliana. Overall this study presents the first biochemical description of the post-translational modification of eIF5A by hypusination which will be functionally relevant for future studies related to the characterization of this pathway in Arabidopsis thaliana.

Belda-Palazon, Borja; Nohales, Maria A.; Rambla, Jose L.; Acena, Jose L.; Delgado, Oscar; Fustero, Santos; Martinez, M. Carmen; Granell, Antonio; Carbonell, Juan; Ferrando, Alejandro

2014-01-01

8

Inactivation of eukaryotic initiation factor 5A (eIF5A) by specific acetylation of its hypusine residue by spermidine/spermine acetyltransferase 1 (SSAT1)  

PubMed Central

SYNOPSIS The eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein containing hypusine, [N?-(4-amino-2-hydroxybutyl)lysine]. eIF5A is activated by the posttranslational synthesis of hypusine and the hypusine modification is essential for cell proliferation. In this study, we report selective acetylation of the hypusine and/or deoxyhypusine residue of eIF5A by a key polyamine catabolic enzyme, spermidine/spermine- N1-acetyltransferase 1 (SSAT1). This enzyme normally catalyzes the N1-acetylation of spermine and spermidine to form acetyl-derivatives, which in turn are degraded to lower polyamines. Although SSAT1 has been reported to exert other effects in cells by its interaction with other cellular proteins, eIF5A is the first target protein specifically acetylated by SSAT1. Hypusine or deoxyhypusine, as the free amino acid, does not act as a substrate for SSAT1, suggesting a macromolecular interaction between eIF5A and SSAT1. Indeed, the binding of eIF5A and SSAT1 was confirmed by pull-down assays. The effect of the acetylation of hypusine on eIF5A activity was assessed by comparison of acetylated vs non-acetylated bovine testis eIF5A in the methionyl-puromycin synthesis assay. The loss of eIF5A activity by this SSAT1-mediated acetylation confirms the strict structural requirement for the hypusine side chain and suggests a possible regulation of eIF5A by hypusine acetylation/deacetylation.

LEE, Seung Bum; PARK, Jong Hwan; FOLK, J.E.; DECK, Jason A.; PEGG, Anthony E.; SOKABE, Masaaki; FRASER, Christopher S.; PARK, Myung Hee

2010-01-01

9

Effects of novel C-methylated spermidine analogs on cell growth via hypusination of eukaryotic translation initiation factor 5A.  

PubMed

The polyamines, putrescine, spermidine, and spermine, are ubiquitous multifunctional cations essential for cellular proliferation. One specific function of spermidine in cell growth is its role as a butylamine donor for hypusine synthesis in the eukaryotic initiation factor 5A (eIF5A). Here, we report the ability of novel mono-methylated spermidine analogs (?-MeSpd, ?-MeSpd, ?-MeSpd, and ?-MeSpd) to function in the hypusination of eIF5A and in supporting the growth of DFMO-treated DU145 cells. We also tested them as substrates and inhibitors for deoxyhypusine synthase (DHS) in vitro. Of these compounds, ?-MeSpd, ?-MeSpd, and ?-MeSpd (but not ?-MeSpd) were substrates for DHS in vitro, while they all inhibited the enzyme reaction. As racemic mixtures, only ?-MeSpd and ?-MeSpd supported long-term growth (9-18 days) of spermidine-depleted DU145 cells, whereas ?-MeSpd and ?-MeSpd did not. The S-enantiomer of ?-MeSpd, which supported long-term growth, was a good substrate for DHS in vitro, whereas the R-isomer was not. The long-term growth of DFMO-treated cells correlated with the hypusine modification of eIF5A by intracellular methylated spermidine analogs. These results underscore the critical requirement for hypusine modification in mammalian cell proliferation and provide new insights into the specificity of the deoxyhypusine synthase reaction. PMID:21861168

Hyvönen, Mervi T; Keinänen, Tuomo A; Khomutov, Maxim; Simonian, Alina; Vepsäläinen, Jouko; Park, Jong Hwan; Khomutov, Alex R; Alhonen, Leena; Park, Myung Hee

2012-02-01

10

Characterization of hypusine-containing 21,000-dalton protein in Neurospora crassa  

SciTech Connect

The deoxyhypusine/hypusine-containing 21,000-dalton protein was labeled by ({sup 3}H)spermidine both in vitro and in vivo in polyamine depleted Neurospora crassa arg-12 ota aga and aga mutants. The in vitro labeling of the 21,000-dalton protein could be dramatically stimulated by NAD{sup +} and NADP{sup +} but not by FMN or FAD. The in vitro labeled 21,000-dalton protein contained the radioactivity of deoxyhypusine and hypusine with a ratio of 2 to 1. The in vivo labeled protein resulted only in hypusine. Three isoform structures of the in vitro labeled 21,000-dalton protein were found with pl values ranging from 5.2 to 6.5. In contrast, the 21,000-dalton protein metabolically labeled in vivo with ({sup 3}H)ornithine gave only one spot with a pl value of 3.5. The deoxyhypusine-modifying enzyme is heat labile and has a half life of 40 min. The complete inhibition of deoxyhypusine-modifying enzyme by NEM and pCMBS suggests that the sulfhydryl group is required for the activity. The unmodified 21,000-dalton protein is heat stable and has a half life of more than 5 hrs. In order to determine the functional role of hypusine modification of 21,000-dalton protein, a protein synthesizing cell-free system has been established to translate endogenous mRNA to discrete polypeptides ranging up to 200,000-dalton. The inhibitory effect of spermidine on protein synthesis in cell-free system of unmodified 21,000-dalton protein is in contrast to the stimulatory effect on protein synthesis in cell-free system of modified protein, suggesting that unmodified 21,000-dalton protein might be responsible for the inhibitory effect of spermidine on protein synthesis in cell-free system containing unmodified 21,000-dalton protein.

Yang, Yunchung.

1989-01-01

11

Tissue transglutaminase expression affects hypusine metabolism in BALB\\/c 3T3 cells  

Microsoft Academic Search

Post-translational formation of hypusine in eukaryotic initiation factor 5A (eIF-5A) is essential for cell viability. Recently, we showed that hypusine protein is an in vitro substrate for transglutaminases (TGases). We report the effect of tissue TGase expression on the in vivo hypusine metabolic pathway. The stable expression of tTGase in BALB\\/c 3T3 cells induced a 100-fold reduction of hypusine levels

S Beninati; V Gentile; M Caraglia; A Lentini; P Tagliaferri; A Abbruzzese

1998-01-01

12

Expression of Eukaryotic Initiation Factor 5A and Hypusine Forming Enzymes in Glioblastoma Patient Samples: Implications for New Targeted Therapies  

PubMed Central

Glioblastomas are highly aggressive brain tumors of adults with poor clinical outcome. Despite a broad range of new and more specific treatment strategies, therapy of glioblastomas remains challenging and tumors relapse in all cases. Recent work demonstrated that the posttranslational hypusine modification of the eukaryotic initiation factor 5A (eIF-5A) is a crucial regulator of cell proliferation, differentiation and an important factor in tumor formation, progression and maintenance. Here we report that eIF-5A as well as the hypusine-forming enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) are highly overexpressed in glioblastoma patient samples. Importantly, targeting eIF-5A and its hypusine modification with GC7, a specific DHS-inhibitor, showed a strong antiproliferative effect in glioblastoma cell lines in vitro, while normal human astrocytes were not affected. Furthermore, we identified p53 dependent premature senescence, a permanent cell cycle arrest, as the primary outcome in U87-MG cells after treatment with GC7. Strikingly, combined treatment with clinically relevant alkylating agents and GC7 had an additive antiproliferative effect in glioblastoma cell lines. In addition, stable knockdown of eIF-5A and DHS by short hairpin RNA (shRNA) could mimic the antiproliferative effects of GC7. These findings suggest that pharmacological inhibition of eIF-5A may represent a novel concept to treat glioblastomas and may help to substantially improve the clinical course of this tumor entity.

Preukschas, Michael; Hagel, Christian; Schulte, Alexander; Weber, Kristoffer; Lamszus, Katrin; Sievert, Henning; Pallmann, Nora; Bokemeyer, Carsten; Hauber, Joachim; Braig, Melanie; Balabanov, Stefan

2012-01-01

13

A tumour suppressor network relying on the polyamine-hypusine axis.  

PubMed

Tumour suppressor genes encode a broad class of molecules whose mutational attenuation contributes to malignant progression. In the canonical situation, the tumour suppressor is completely inactivated through a two-hit process involving a point mutation in one allele and chromosomal deletion of the other. Here, to identify tumour suppressor genes in lymphoma, we screen a short hairpin RNA library targeting genes deleted in human lymphomas. We functionally identify those genes whose suppression promotes tumorigenesis in a mouse lymphoma model. Of the nine tumour suppressors we identified, eight correspond to genes occurring in three physically linked 'clusters', suggesting that the common occurrence of large chromosomal deletions in human tumours reflects selective pressure to attenuate multiple genes. Among the new tumour suppressors are adenosylmethionine decarboxylase 1 (AMD1) and eukaryotic translation initiation factor 5A (eIF5A), two genes associated with hypusine, a unique amino acid produced as a product of polyamine metabolism through a highly conserved pathway. Through a secondary screen surveying the impact of all polyamine enzymes on tumorigenesis, we establish the polyamine-hypusine axis as a new tumour suppressor network regulating apoptosis. Unexpectedly, heterozygous deletions encompassing AMD1 and eIF5A often occur together in human lymphomas and co-suppression of both genes promotes lymphomagenesis in mice. Thus, some tumour suppressor functions can be disabled through a two-step process targeting different genes acting in the same pathway. PMID:22722845

Scuoppo, Claudio; Miething, Cornelius; Lindqvist, Lisa; Reyes, José; Ruse, Cristian; Appelmann, Iris; Yoon, Seungtai; Krasnitz, Alexander; Teruya-Feldstein, Julie; Pappin, Darryl; Pelletier, Jerry; Lowe, Scott W

2012-07-12

14

A tumour suppressor network relying on the polyamine-hypusine axis  

PubMed Central

Tumour suppressor genes encode a broad class of molecules whose mutational attenuation contributes to malignant progression. In the canonical situation, the tumour suppressor is completely inactivated through a two-hit process involving a point mutation in one allele and chromosomal deletion of the other1. Here, to identify tumour suppressor genes in lymphoma, we screen a short hairpin RNA library targeting genes deleted in human lymphomas. We functionally identify those genes whose suppression promotes tumorigenesis in a mouse lymphoma model. Of the nine tumour suppressors we identified, eight correspond to genes occurring in three physically linked ‘clusters’, suggesting that the common occurrence of large chromosomal deletions in human tumours reflects selective pressure to attenuate multiple genes. Among the new tumour suppressors are adenosylmethionine decarboxylase 1 (AMD1) and eukaryotic translation initiation factor 5A (eIF5A), two genes associated with hypusine, a unique amino acid produced as a product of polyamine metabolism through a highly conserved pathway2. Through a secondary screen surveying the impact of all polyamine enzymes on tumorigenesis, we establish the polyamine–hypusine axis as a new tumour suppressor network regulating apoptosis. Unexpectedly, heterozygous deletions encompassing AMD1 and eIF5A often occur together in human lymphomas and co-suppression of both genes promotes lymphomagenesis in mice. Thus, some tumour suppressor functions can be disabled through a two-step process targeting different genes acting in the same pathway.

Scuoppo, Claudio; Miething, Cornelius; Lindqvist, Lisa; Reyes, Jose; Ruse, Cristian; Appelmann, Iris; Yoon, Seungtai; Krasnitz, Alexander; Teruya-Feldstein, Julie; Pappin, Darryl; Pelletier, Jerry; Lowe, Scott W.

2012-01-01

15

The Histone Code of Toxoplasma gondii Comprises Conserved and Unique Posttranslational Modifications  

PubMed Central

ABSTRACT Epigenetic gene regulation has emerged as a major mechanism for gene regulation in all eukaryotes. Histones are small, basic proteins that constitute the major protein component of chromatin, and posttranslational modifications (PTM) of histones are essential for epigenetic gene regulation. The different combinations of histone PTM form the histone code for an organism, marking functional units of chromatin that recruit macromolecular complexes that govern chromatin structure and regulate gene expression. To characterize the repertoire of Toxoplasma gondii histone PTM, we enriched histones using standard acid extraction protocols and analyzed them with several complementary middle-down and bottom-up proteomic approaches with the high-resolution Orbitrap mass spectrometer using collision-induced dissociation (CID), higher-energy collisional dissociation (HCD), and/or electron transfer dissociation (ETD) fragmentation. We identified 249 peptides with unique combinations of PTM that comprise the T. gondii histone code. T. gondii histones share a high degree of sequence conservation with human histones, and many modifications are conserved between these species. In addition, T. gondii histones have unique modifications not previously identified in other species. Finally, T. gondii histones are modified by succinylation, propionylation, and formylation, recently described histone PTM that have not previously been identified in parasitic protozoa. The characterization of the T. gondii histone code will facilitate in-depth analysis of how epigenetic regulation affects gene expression in pathogenic apicomplexan parasites and identify a new model system for elucidating the biological functions of novel histone PTM.

Nardelli, Sheila C.; Che, Fa-Yun; Silmon de Monerri, Natalie C.; Xiao, Hui; Nieves, Edward; Madrid-Aliste, Carlos; Angel, Sergio O.; Sullivan, William J.; Angeletti, Ruth H.; Kim, Kami; Weiss, Louis M.

2013-01-01

16

Unique translational modification of an invertebrate neuropeptide: a phosphorylated member of the adipokinetic hormone peptide family  

PubMed Central

Separation of an extract of corpora cardiaca from the protea beetle, Trichostetha fascicularis, by single-step RP (reverse-phase)-HPLC and monitoring of tryptophan fluorescence resulted in two distinctive peaks, the material of which mobilized proline and carbohydrates in a bioassay performed using the beetle. Material from one of these peaks was; however, inactive in the classical bioassays of locusts and cockroaches that are used for detecting peptides belonging to the AKH (adipokinetic hormone) family. After enzymatically deblocking the N-terminal pyroglutamic acid (pGlu) residue in the peptide material and sequencing by Edman degradation, a partial sequence was obtained: (pGlu)-Ile-Asn-Met-Thr-Xaa-Gly-Trp. The complete sequence was deduced from ESI-MSn (electrospray ionization multi-stage-MS); position six was identified as a phosphothreonine residue and the C-terminus is amidated. The peptide, code-named Trifa-CC, was chemically synthesized and used in confirmatory experiments to show that the primary structure had been correctly assigned. To our knowledge, this is the first report of a phosphorylated invertebrate neuropeptide. Synthetic Trifa-CC co-elutes with the natural peptide, found in the gland of the protea beetle, after RP-HPLC. Moreover, the natural peptide can be dephosphorylated by alkaline phosphatase and the product of that reaction has the same retention time as a synthetic nonphosphorylated octapeptide which has the same sequence as Trifa-CC. Finally, synthetic Trifa-CC has hypertrehalosaemic and hyperprolinaemic biological activity in the protea beetle, but even high concentrations of synthetic Trifa-CC are inactive in locusts and cockroaches. Hence, the correct peptide structure has been assigned. Trifa-CC of the protea beetle is an unusual member of the AKH family that is unique in its post-translational modification. Since it increases the concentration of carbohydrates and proline in the haemolymph when injected into the protea beetle, and since these substrates are also used during flight, we hypothesize that Trifa-CC controls the mobilization of these metabolites in the protea beetle.

2005-01-01

17

Unique translational modification of an invertebrate neuropeptide: a phosphorylated member of the adipokinetic hormone peptide family.  

PubMed

Separation of an extract of corpora cardiaca from the protea beetle, Trichostetha fascicularis, by single-step RP (reverse-phase)-HPLC and monitoring of tryptophan fluorescence resulted in two distinctive peaks, the material of which mobilized proline and carbohydrates in a bioassay performed using the beetle. Material from one of these peaks was; however, inactive in the classical bioassays of locusts and cockroaches that are used for detecting peptides belonging to the AKH (adipokinetic hormone) family. After enzymatically deblocking the N-terminal pyroglutamic acid (pGlu) residue in the peptide material and sequencing by Edman degradation, a partial sequence was obtained: (pGlu)-Ile-Asn-Met-Thr-Xaa-Gly-Trp. The complete sequence was deduced from ESI-MS(n) (electrospray ionization multi-stage-MS); position six was identified as a phosphothreonine residue and the C-terminus is amidated. The peptide, code-named Trifa-CC, was chemically synthesized and used in confirmatory experiments to show that the primary structure had been correctly assigned. To our knowledge, this is the first report of a phosphorylated invertebrate neuropeptide. Synthetic Trifa-CC co-elutes with the natural peptide, found in the gland of the protea beetle, after RP-HPLC. Moreover, the natural peptide can be dephosphorylated by alkaline phosphatase and the product of that reaction has the same retention time as a synthetic nonphosphorylated octapeptide which has the same sequence as Trifa-CC. Finally, synthetic Trifa-CC has hypertrehalosaemic and hyperprolinaemic biological activity in the protea beetle, but even high concentrations of synthetic Trifa-CC are inactive in locusts and cockroaches. Hence, the correct peptide structure has been assigned. Trifa-CC of the protea beetle is an unusual member of the AKH family that is unique in its post-translational modification. Since it increases the concentration of carbohydrates and proline in the haemolymph when injected into the protea beetle, and since these substrates are also used during flight, we hypothesize that Trifa-CC controls the mobilization of these metabolites in the protea beetle. PMID:16271039

Gäde, Gerd; Simek, Petr; Clark, Kevin D; Auerswald, Lutz

2006-02-01

18

De novo sequencing of unique sequence tags for discovery of post-translational modifications of proteins  

SciTech Connect

De novo sequencing has a promise to discover the protein post-translation modifications; however, such approach is still in their infancy and not widely applied for proteomics practices due to its limited reliability. In this work, we describe a de novo sequencing approach for discovery of protein modifications through identification of the UStags (Anal. Chem. 2008, 80, 1871-1882). The de novo information was obtained from Fourier-transform tandem mass spectrometry for peptides and polypeptides in a yeast lysate, and the de novo sequences obtained were filtered to define a more limited set of UStags. The DNA-predicted database protein sequences were then compared to the UStags, and the differences observed across or in the UStags (i.e., the UStags’ prefix and suffix sequences and the UStags themselves) were used to infer the possible sequence modifications. With this de novo-UStag approach, we uncovered some unexpected variances of yeast protein sequences due to amino acid mutations and/or multiple modifications to the predicted protein sequences. Random matching of the de novo sequences to the predicted sequences were examined with use of two random (false) databases, and ~3% false discovery rates were estimated for the de novo-UStag approach. The factors affecting the reliability (e.g., existence of de novo sequencing noise residues and redundant sequences) and the sensitivity are described. The de novo-UStag complements the UStag method previously reported by enabling discovery of new protein modifications.

Shen, Yufeng; Tolic, Nikola; Hixson, Kim K.; Purvine, Samuel O.; Anderson, Gordon A.; Smith, Richard D.

2008-10-15

19

De Novo Sequencing of Unique Sequence Tags for Discovery of Post-Translational Modifications of Proteins  

PubMed Central

De novo sequencing is a spectrum analysis approach for mass spectrometry data to discover post-translational modifications in proteins; however, such an approach is still in its infancy and is still not widely applied to proteomic practices due to its limited reliability. In this work, we describe a de novo sequencing approach for the discovery of protein modifications based on identification of the proteome UStags. The de novo information was obtained from Fourier-transform tandem mass spectrometry data for peptides and polypeptides from a yeast lysate, and the de novo sequences obtained were selected based on filter levels designed to provide a limited yet high quality subset of UStags. The DNA-predicted database protein sequences were then compared to the UStags, and the differences observed across or in the UStags (i.e., the UStags’ prefix and suffix sequences and the UStags themselves) were used to infer possible sequence modifications. With this de novo–UStag approach, we uncovered some unexpected variances within several yeast protein sequences due to amino acid mutations and/or multiple modifications to the predicted protein sequences. To determine false discovery rates, two random (false) databases were independently used for sequence matching, and ?3% false discovery rates were estimated for the de novo–UStag approach. The factors affecting the reliability (e.g., existence of de novo sequencing noise residues and redundant sequences) and the sensitivity of the approach were investigated and described. The combined de novo–UStag approach complements the UStag method previously reported by enabling the discovery of new protein modifications.

Shen, Yufeng; Tolic, Nikola; Hixson, Kim K.; Purvine, Samuel O.; Anderson, Gordon A.; Smith, Richard D.

2009-01-01

20

Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii  

PubMed Central

Acinetobacter baumannii is a nosocomial opportunistic pathogen that can cause severe infections, including hospital-acquired pneumonia, wound infections, and sepsis. Multidrug-resistant (MDR) strains are prevalent, further complicating patient treatment. Due to the increase in MDR strains, the cationic antimicrobial peptide colistin has been used to treat A. baumannii infections. Colistin-resistant strains of A. baumannii with alterations to the lipid A component of lipopolysaccharide (LPS) have been reported; specifically, the lipid A structure was shown to be hepta-acylated with a phosphoethanolamine (pEtN) modification present on one of the terminal phosphate residues. Using a tandem mass spectrometry platform, we provide definitive evidence that the lipid A isolated from colistin-resistant A. baumannii MAC204 LPS contains a novel structure corresponding to a diphosphoryl hepta-acylated lipid A structure with both pEtN and galactosamine (GalN) modifications. To correlate our structural studies with clinically relevant samples, we characterized colistin-susceptible and -resistant isolates obtained from patients. These results demonstrated that the clinical colistin-resistant isolate had the same pEtN and GalN modifications as those seen in the laboratory-adapted A. baumannii strain MAC204. In summary, this work has shown complete structure characterization including the accurate assignment of acylation, phosphorylation, and glycosylation of lipid A from A. baumannii, which are important for resistance to colistin.

Pelletier, Mark R.; Casella, Leila G.; Jones, Jace W.; Adams, Mark D.; Zurawski, Daniel V.; Hazlett, Karsten R. O.; Doi, Yohei

2013-01-01

21

Unique modifications with phosphocholine and phosphoethanolamine define alternate antigenic forms of Neisseria gonorrhoeae type IV pili.  

PubMed

Several major bacterial pathogens and related commensal species colonizing the human mucosa express phosphocholine (PC) at their cell surfaces. PC appears to impact host-microbe biology by serving as a ligand for both C-reactive protein and the receptor for platelet-activating factor. Type IV pili of Neisseria gonorrhoeae (Ng) and Neisseria meningitidis, filamentous protein structures critical to the colonization of their human hosts, are known to react variably with monoclonal antibodies recognizing a PC epitope. However, the structural basis for this reactivity has remained elusive. To address this matter, we exploited the finding that the PilE pilin subunit in Ng mutants lacking the PilV protein acquired the PC epitope independent of changes in pilin primary structure. Specifically, we show by using mass spectrometry that PilE derived from the pilV background is composed of a mixture of subunits bearing O-linked forms of either phosphoethanolamine (PE) or PC at the same residue, whereas the wild-type background carries only PE at that same site. Therefore, PilV can influence pilin structure and antigenicity by modulating the incorporation of these alternative modifications. The disaccharide covalently linked to Ng pilin was also characterized because it is present on the same peptides bearing the PE and PC modifications and, contrary to previous reports, was found to be linked by means of 2,4-diacetamido-2,4,6-trideoxyhexose. Taken together, these findings provide new insights into Ng type IV pilus structure and antigenicity and resolve long-standing issues regarding the nature of both the PC epitope and the pilin glycan. PMID:15249686

Hegge, Finn Terje; Hitchen, Paul G; Aas, Finn Erik; Kristiansen, Heidi; Løvold, Cecilia; Egge-Jacobsen, Wolfgang; Panico, Maria; Leong, Weng Yee; Bull, Victoria; Virji, Mumtaz; Morris, Howard R; Dell, Anne; Koomey, Michael

2004-07-20

22

Unique modifications with phosphocholine and phosphoethanolamine define alternate antigenic forms of Neisseria gonorrhoeae type IV pili  

PubMed Central

Several major bacterial pathogens and related commensal species colonizing the human mucosa express phosphocholine (PC) at their cell surfaces. PC appears to impact host–microbe biology by serving as a ligand for both C-reactive protein and the receptor for platelet-activating factor. Type IV pili of Neisseria gonorrhoeae (Ng) and Neisseria meningitidis, filamentous protein structures critical to the colonization of their human hosts, are known to react variably with monoclonal antibodies recognizing a PC epitope. However, the structural basis for this reactivity has remained elusive. To address this matter, we exploited the finding that the PilE pilin subunit in Ng mutants lacking the PilV protein acquired the PC epitope independent of changes in pilin primary structure. Specifically, we show by using mass spectrometry that PilE derived from the pilV background is composed of a mixture of subunits bearing O-linked forms of either phosphoethanolamine (PE) or PC at the same residue, whereas the wild-type background carries only PE at that same site. Therefore, PilV can influence pilin structure and antigenicity by modulating the incorporation of these alternative modifications. The disaccharide covalently linked to Ng pilin was also characterized because it is present on the same peptides bearing the PE and PC modifications and, contrary to previous reports, was found to be linked by means of 2,4-diacetamido-2,4,6-trideoxyhexose. Taken together, these findings provide new insights into Ng type IV pilus structure and antigenicity and resolve long-standing issues regarding the nature of both the PC epitope and the pilin glycan.

Hegge, Finn Terje; Hitchen, Paul G.; Aas, Finn Erik; Kristiansen, Heidi; L?vold, Cecilia; Egge-Jacobsen, Wolfgang; Panico, Maria; Leong, Weng Yee; Bull, Victoria; Virji, Mumtaz; Morris, Howard R.; Dell, Anne; Koomey, Michael

2004-01-01

23

G-rich VEGF aptamer with locked and unlocked nucleic acid modifications exhibits a unique G-quadruplex fold.  

PubMed

The formation of a single G-quadruplex structure adopted by a promising 25 nt G-rich vascular endothelial growth factor aptamer in a K(+) rich environment was facilitated by locked nucleic acid modifications. An unprecedented all parallel-stranded monomeric G-quadruplex with three G-quartet planes exhibits several unique structural features. Five consecutive guanine residues are all involved in G-quartet formation and occupy positions in adjacent DNA strands, which are bridged with a no-residue propeller-type loop. A two-residue D-shaped loop facilitates inclusion of an isolated guanine residue into the vacant spot within the G-quartet. The remaining two G-rich tracts of three residues each adopt parallel orientation and are linked with edgewise and propeller loops. Both 5' with 3 nt and 3' with 4 nt overhangs display well-defined conformations, with latter adopting a basket handle topology. Locked residues contribute to thermal stabilization of the adopted structure and formation of structurally pre-organized intermediates that facilitate folding into a single G-quadruplex. Understanding the impact of chemical modifications on folding, thermal stability and structural polymorphism of G-quadruplexes provides means for the improvement of vascular endothelial growth factor aptamers and advances our insights into driving nucleic acid structure by locking or unlocking the conformation of sugar moieties of nucleotides in general. PMID:23935071

Maruši?, Maja; Veedu, Rakesh N; Wengel, Jesper; Plavec, Janez

2013-11-01

24

Modification of NASA Langley 8 Foot High Temperature Tunnel to provide a unique national research facility for hypersonic air-breathing propulsion systems  

NASA Technical Reports Server (NTRS)

A planned modification of the NASA Langley 8-Foot High Temperature Tunnel to make it a unique national research facility for hypersonic air-breathing propulsion systems is described, and some of the ongoing supporting research for that modification is discussed. The modification involves: (1) the addition of an oxygen-enrichment system which will allow the methane-air combustion-heated test stream to simulate air for propulsion testing; and (2) supplemental nozzles to expand the test simulation capability from the current nominal Mach number to 7.0 include Mach numbers 3.0, 4.5, and 5.0. Detailed design of the modifications is currently underway and the modified facility is scheduled to be available for tests of large scale propulsion systems by mid 1988.

Kelly, H. N.; Wieting, A. R.

1984-01-01

25

Modification of NASA Langley 8 foot high temperature tunnel to provide a unique national research facility for hypersonic air-breathing propulsion systems  

NASA Technical Reports Server (NTRS)

A planned modification of the NASA Langley 8-Foot High Temperature Tunnel to make it a unique national research facility for hypersonic air-breathing propulsion systems is described, and some of the ongoing supporting research for that modification is discussed. The modification involves: (1) the addition of an oxygen-enrichment system which will allow the methane-air combustion-heated test stream to simulate air for propulsion testing; and (2) supplemental nozzles to expand the test simulation capability from the current nominal Mach number to 7.0 include Mach numbers 3.0, 4.5, and 5.0. Detailed design of the modifications is currently underway and the modified facility is scheduled to be available for tests of large scale propulsion systems by mid 1988.

Kelly, H. N.; Wieting, A. R.

1984-01-01

26

eIF5A and EF-P: two unique translation factors are now traveling the same road.  

PubMed

Translational control is extremely important in all organisms, and some of its aspects are highly conserved among all primary kingdoms, such as those related to the translation elongation step. The previously classified translation initiation factor 5A (eIF5A) and its bacterial homologue elongation factor P (EF-P) were discovered in the late 70's and have recently been the object of many studies. eIF5A and EF-P are the only cellular proteins that undergo hypusination and lysinylation, respectively, both of which are unique posttranslational modifications. Herein, we review all the important discoveries related to the biochemical and functional characterization of these factors, highlighting the implication of eIF5A in translation elongation instead of initiation. The findings that eIF5A and EF-P are important for specific cellular processes and play a role in the relief of ribosome stalling caused by specific amino acid sequences, such as those containing prolines reinforce the hypothesis that these factors are involved in specialized translation. Although there are some divergences between these unique factors, recent studies have clarified that they act similarly during protein synthesis. Further studies may reveal their precise mechanism of ribosome activity modulation as well as the mRNA targets that require eIF5A and EF-P for their proper translation. PMID:24402910

Rossi, Danuza; Kuroshu, Reginaldo; Zanelli, Cleslei Fernando; Valentini, Sandro Roberto

2014-01-01

27

Characterization of Unique Modification of Flagellar Rod Protein FlgG by Campylobacter jejuni Lipid A Phosphoethanolamine Transferase, Linking Bacterial Locomotion and Antimicrobial Peptide Resistance*  

PubMed Central

Gram-negative bacteria assemble complex surface structures that interface with the surrounding environment and are involved in pathogenesis. Recent work in Campylobacter jejuni identified a gene encoding a novel phosphoethanolamine (pEtN) transferase Cj0256, renamed EptC, that serves a dual role in modifying the flagellar rod protein, FlgG, and the lipid A domain of C. jejuni lipooligosaccharide with a pEtN residue. In this work, we characterize the unique post-translational pEtN modification of FlgG using collision-induced and electron transfer dissociation mass spectrometry, as well as a genetic approach using site-directed mutagenesis to determine the site of modification. Specifically, we show that FlgG is modified with pEtN at a single site (Thr75) by EptC and demonstrate enzyme specificity by showing that EptC is unable to modify other amino acids (e.g. serine and tyrosine). Using Campylobacter strains expressing site-directed FlgG mutants, we also show that defects in motility arise directly from the loss of pEtN modification of FlgG. Interestingly, alignments of FlgG from most epsilon proteobacteria reveal a conserved site of modification. Characterization of EptC and its enzymatic targets expands on the increasingly important field of prokaryotic post-translational modification of bacterial surface structures and the unidentified role they may play in pathogenesis.

Cullen, Thomas W.; Madsen, James A.; Ivanov, Petko L.; Brodbelt, Jennifer S.; Trent, M. Stephen

2012-01-01

28

Cofactor Biosynthesis through Protein Post-Translational Modification  

PubMed Central

Post-translational modifications of amino acids can be used to generate novel cofactors capable of chemistries inaccessible to conventional amino acid side chains. The biosynthesis of these sites often requires one or more enzyme or protein accessory factors, the functions of which are quite diverse and often difficult to isolate in cases where multiple enzymes are involved. Herein is described the current knowledge of the biosynthesis of urease and nitrile hydratase metal centers, pyrroloquinoline quinone, hypusine, and tryptophan tryptophylquinone cofactors along with the most recent work elucidating the functions of individual accessory factors in these systems. These examples showcase the breadth and diversity of this continually expanding field.

Yukl, Erik T.; Wilmot, Carrie M.

2012-01-01

29

Induced gene expression of the hypusine-containing protein eukaryotic initiation factor 5A in activated human T lymphocytes.  

PubMed Central

The hypusine-containing protein eukaryotic initiation factor 5A (eIF-5A) is a cellular cofactor critically required for the function of the Rev transactivator protein of human immunodeficiency virus type 1 (HIV-1). eIF-5A localizes in the nuclear and cytoplasmic compartments of mammalian cells, suggesting possible activities on the level of regulated mRNA transport and/or protein translation. In this report we show that eIF-5A gene expression is constitutively low but inducible with T-lymphocyte-specific stimuli in human peripheral blood mononuclear cells (PBMCs) of healthy individuals. In contrast, eIF-5A is constitutively expressed at high levels in human cell lines as well as in various human organs. Comparison of eIF-5A levels in the PBMCs of uninfected and HIV-1-infected donors shows a significant upregulation of eIF-5A gene expression in the PBMCs of HIV-1 patients, compatible with a possible role of eIF-5A in HIV-1 replication during T-cell activation. Images

Bevec, D; Klier, H; Holter, W; Tschachler, E; Valent, P; Lottspeich, F; Baumruker, T; Hauber, J

1994-01-01

30

Analysis of pseudorabies virus glycoprotein gIII localization and modification by using novel infectious viral mutants carrying unique EcoRI sites.  

PubMed Central

We have constructed two pseudorabies virus (PRV) mutants, each with a unique EcoRI restriction site in the nonessential gIII envelope glycoprotein gene. Since no natural PRV isolate has been reported to contain EcoRI sites, the isolation and single-step growth curve analysis of these mutants established that PRV can carry such a site with little ill effect in tissue culture. Virus carrying these defined mutations produced novel gIII proteins that enabled us to begin functional assignment of protein localization information within the gIII gene. Specifically, one viral mutant contained an in-frame synthetic EcoRI linker sequence that was flanked on one side by the first one-third of the gIII gene and on the other side by the last one-third of the gene. The resulting protein lacked the middle one-third of the parental species, including five of eight putative N-linked glycosylation signals, but was still glycosylated and found in enveloped virions; it was not secreted into the medium. A second viral mutant contained an in-frame synthetic EcoRI linker sequence that additionally specified a nonsense codon at position 158, producing a gIII protein that was glycosylated and secreted into the medium; the fragment was not found in enveloped virions. By endoglycosidase and pulse-chase analyses, we established a precursor-product relationship between the various forms of gIII expressed in the parental and mutant strains, and perhaps determined certain features of the gIII protein that are required for its efficient export within the cell. Images

Ryan, J P; Whealy, M E; Robbins, A K; Enquist, L W

1987-01-01

31

Genetic modification and genetic determinism.  

PubMed

In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions. PMID:16800884

Resnik, David B; Vorhaus, Daniel B

2006-01-01

32

Genetic modification and genetic determinism  

PubMed Central

In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions.

Resnik, David B; Vorhaus, Daniel B

2006-01-01

33

Endocrinology in Thailand: Unique challenges, unique solutions  

PubMed Central

Thailand is a developing country in Southeast Asia with a nationally acknowledged requirement for improvement of the medical system. At present, endocrinology is a specific branch of medicine that is taught in few medical schools. There are very few endocrinologists in Thailand, who are unable to cope with the large number of patients with endocrinology problems. Primary care for common endocrine disorders, such as diabetes mellitus and thyroid disease, is still the domain of general practitioners. In this article, the author will present unique challenges and unique solutions of endocrinology practice in Thailand.

Wiwanitkit, Viroj

2011-01-01

34

Unique Instruments' Origins  

NSDL National Science Digital Library

The purpose of this activity is to help you find unique instruments from a specific country. For whatever country you have chosen, the following resources should help you locate some unique instruments from that country. For starters, check out this link: Instruments By Country You will find a list of musical instruments for many countries in the world. Once you find an instrument from your country you want to explore, look here: Unique World Instruments Here ...

Smith, Mr.

2012-09-11

35

Blocking eIF5A modification in cervical cancer cells alters the expression of cancer-related genes and suppresses cell proliferation.  

PubMed

Cancer etiology is influenced by alterations in protein synthesis that are not fully understood. In this study, we took a novel approach to investigate the role of the eukaryotic translation initiation factor eIF5A in human cervical cancers, where it is widely overexpressed. eIF5A contains the distinctive amino acid hypusine, which is formed by a posttranslational modification event requiring deoxyhypusine hydroxylase (DOHH), an enzyme that can be inhibited by the drugs ciclopirox and deferiprone. We found that proliferation of cervical cancer cells can be blocked by DOHH inhibition with either of these pharmacologic agents, as well as by RNA interference-mediated silencing of eIF5A, DOHH, or another enzyme in the hypusine pathway. Proteomic and RNA analyses in HeLa cervical cancer cells identified two groups of proteins in addition to eIF5A that were coordinately affected by ciclopirox and deferiprone. Group 1 proteins (Hsp27, NM23, and DJ-1) were downregulated at the translational level, whereas group 2 proteins (TrpRS and PRDX2) were upregulated at the mRNA level. Further investigations confirmed that eIF5A and DOHH are required for Hsp27 expression in cervical cancer cells and for regulation of its key target I?B and hence NF-?B. Our results argue that mature eIF5A controls a translational network of cancer-driving genes, termed the eIF5A regulon, at the levels of mRNA abundance and translation. In coordinating cell proliferation, the eIF5A regulon can be modulated by drugs such as ciclopirox or deferiprone, which might be repositioned to control cancer cell growth. PMID:24220243

Mémin, Elisabeth; Hoque, Mainul; Jain, Mohit R; Heller, Debra S; Li, Hong; Cracchiolo, Bernadette; Hanauske-Abel, Hartmut M; Pe'ery, Tsafi; Mathews, Michael B

2014-01-15

36

Home Modifications  

MedlinePLUS

... understanding of the mechanisms involved. Where Do You Begin? Before you make home modifications, you should evaluate ... rebuildingtogether.org/content/resource/detail/1192/ You can begin your survey by examining each area of your ...

37

Predicting the pathway involved in post-translational modification of Elongation factor P in a subset of bacterial species  

Microsoft Academic Search

BACKGROUND: The bacterial elongation factor P (EF-P) is strictly conserved in bacteria and essential for protein synthesis. It is homologous to the eukaryotic translation initiation factor 5A (eIF5A). A highly conserved eIF5A lysine is modified into an unusual amino acid derived from spermidine, hypusine. Hypusine is absolutely required for eIF5A's role in translation in Saccharomyces cerevisiae. The homologous lysine of

Marc Bailly; Valérie de Crécy-Lagard

2010-01-01

38

Unique Access to Learning  

ERIC Educational Resources Information Center

This article describes the many learning opportunities that broadcast technology students at Ladue Horton Watkins High School in St. Louis, Missouri, experience because of their unique access to technology and methods of learning. Through scaffolding, stepladder techniques, and trial by fire, students learn to produce multiple television programs,…

Goble, Don

2009-01-01

39

Histone modification in Drosophila.  

PubMed

Post-translational modifications (PTMs) of nucleosomal core histones play roles in basic biological processes via altering chromatin structure and creating target sites for proteins acting on chromatin. Several features make Drosophila a uniquely effective model for studying PTMs. Position effect variegation, polycomb repression, dosage compensation and several other processes extensively studied by the powerful tools of Drosophila genetics as well as polytene chromosome cytology reveal information on the dynamic changes of histone PTMs and factors that deposit, remove and recognize these. Recent determination of the genome-wide distribution of more than 20 different histone PTM types has resulted in a highly detailed view of chromatin landscape. This review samples from the wealth of data these analyses have provided together with data resulting from gene-targeted studies on the distribution and role of specific histone modifications and modifiers. As an example of the complex interactions among PTMs, we will also discuss crosstalk involving specific phosphorylated and acetylated histone forms. PMID:22806479

Boros, Imre M

2012-07-01

40

PDV modifications.  

SciTech Connect

External modifications can transform a conventional photonic doppler velocimetry (PDV) system to other useful configurations - Non-standard probes and Frequency-conversion measurements. This approach is easier than supporting every conceivable measurement in the core PDV design. Circulator specifications may be important - -30 dB isolation (common) probably not be enough, -50 dB isolation is available, and some bench testing may be needed.

Dolan, Daniel H., III

2010-09-01

41

NASA's unique networking environment  

NASA Technical Reports Server (NTRS)

Networking is an infrastructure technology; it is a tool for NASA to support its space and aeronautics missions. Some of NASA's networking problems are shared by the commercial and/or military communities, and can be solved by working with these communities. However, some of NASA's networking problems are unique and will not be addressed by these other communities. Individual characteristics of NASA's space-mission networking enviroment are examined, the combination of all these characteristics that distinguish NASA's networking systems from either commercial or military systems is explained, and some research areas that are important for NASA to pursue are outlined.

Johnson, Marjory J.

1988-01-01

42

Molecular modeling of the human eukaryotic translation initiation factor 5A (eIF5A) based on spectroscopic and computational analyses  

SciTech Connect

The eukaryotic translation initiation factor 5A (eIF5A) is a protein ubiquitously present in archaea and eukarya, which undergoes a unique two-step post-translational modification called hypusination. Several studies have shown that hypusination is essential for a variety of functional roles for eIF5A, including cell proliferation and synthesis of proteins involved in cell cycle control. Up to now neither a totally selective inhibitor of hypusination nor an inhibitor capable of directly binding to eIF5A has been reported in the literature. The discovery of such an inhibitor might be achieved by computer-aided drug design based on the 3D structure of the human eIF5A. In this study, we present a molecular model for the human eIF5A protein based on the crystal structure of the eIF5A from Leishmania brasiliensis, and compare the modeled conformation of the loop bearing the hypusination site with circular dichroism data obtained with a synthetic peptide of this loop. Furthermore, analysis of amino acid variability between different human eIF5A isoforms revealed peculiar structural characteristics that are of functional relevance.

Costa-Neto, Claudio M. [Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, 14049-900 Ribeirao Preto (Brazil)]. E-mail: claudio@fmrp.usp.br; Parreiras-e-Silva, Lucas T. [Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, 14049-900 Ribeirao Preto (Brazil); Ruller, Roberto [Department of Chemistry, FFCLRP, University of Sao Paulo, 14040-901 Ribeirao Preto (Brazil); Oliveira, Eduardo B. [Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, 14049-900 Ribeirao Preto (Brazil); Miranda, Antonio [Department of Biophysics, Escola Paulista de Medicina, UNIFESP, 04023-062 Sao Paulo (Brazil); Oliveira, Laerte [Department of Biophysics, Escola Paulista de Medicina, UNIFESP, 04023-062 Sao Paulo (Brazil); Ward, Richard J. [Department of Chemistry, FFCLRP, University of Sao Paulo, 14040-901 Ribeirao Preto (Brazil)

2006-09-01

43

Cellular dynamics of RNA modification.  

PubMed

Five decades of research have identified more than 100 ribonucleosides that are post-transcriptionally modified. Many modified nucleosides are conserved throughout bacteria, archaea, and eukaryotes, while some are unique to each branch of life. However, the cellular and functional dynamics of RNA modification remain largely unexplored, mostly because of the lack of functional hypotheses and experimental methods for quantification and large-scale analysis. Many RNA modifications are not essential for life, which parallels the observation that many well-characterized protein and DNA modifications are not essential for life. Instead, increasing evidence indicates that RNA modifications can play regulatory roles in cells, especially in response to stress conditions. In this Account, we review some examples of RNA modification that are dynamically controlled in cells. We also discuss some recently developed methods that have enhanced the ability to study the cellular dynamics of RNA modification. We discuss four specific examples of RNA modification in detail here. We begin with 4-thio uridine (s(4)U), which can act as a cellular sensor of near-UV light. Then we consider queuosine (Q), which is a potential biomarker for malignancy. Next we examine N(6)-methyl adenine (m(6)A), which is the prevalent modification in eukaryotic messenger RNAs (mRNAs). Finally, we discuss pseudouridine (?), which is inducible by nutrient deprivation. We then consider two recent technical advances that have stimulated the study of the cellular dynamics in modified ribonucleosides. The first is a genome-wide method that combines primer extension with a microarray. It was used to study the N(1)-methyl adenine (m(1)A) hypomodification in human transfer RNA (tRNA). The second is a quantitative mass spectrometric method used to investigate dynamic changes in a wide range of tRNA modifications under stress conditions in yeast. In addition, we discuss potential mechanisms that control dynamic regulation of RNA modifications as well as hypotheses for discovering potential RNA demodification enzymes. We conclude by highlighting the need to develop new tools and to generate additional hypotheses for how these modifications function in cells. The study of the cellular dynamics of modified RNA remains a largely open area for new development, which underscores the rich potential for important advances as researchers drive this emerging field to the next level. PMID:21615108

Yi, Chengqi; Pan, Tao

2011-12-20

44

Uniqueness Theorem for Black Objects  

SciTech Connect

We shall review the current status of uniqueness theorem for black objects in higher dimensional spacetime. At the beginning we consider static charged asymptotically flat spacelike hypersurface with compact interior with both degenerate and non-degenerate components of the event horizon in n-dimensional spacetime. We gave some remarks concerning partial results in proving uniqueness of stationary axisymmetric multidimensional solutions and winding numbers which can uniquely characterize the topology and symmetry structure of black objects.

Rogatko, Marek [Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, pl. Marii Curie-Sklodowskiej 1 (Poland)

2010-06-23

45

Interest: A Unique Motivational Variable  

ERIC Educational Resources Information Center

In the first part of this article, I discuss motivational variables in general, and interest in specific and propose that because of its biological roots, interest is a unique motivational variable. Furthermore, it is suggested that to demonstrate the uniqueness of interest, neuroscientific findings need to be considered. In the second section of…

Hidi, Suzanne

2006-01-01

46

On the Meaning of Uniqueness  

ERIC Educational Resources Information Center

This article analyzes four questions on the meaning of uniqueness that have contrasting answers in common language versus mathematical language. The investigations stem from a scenario in which students interpreted uniqueness according to a definition from standard English, that is, different from the mathematical meaning, in defining an injective…

Shipman, Barbara A.

2013-01-01

47

Émission de photons uniques par un atome unique piégé  

NASA Astrophysics Data System (ADS)

En illuminant un atome unique piégé dans une pince optique de taille micrométrique à l'aide d'impulsions lumineuses résonantes d'une durée de 4?ns, nous avons réalisé une source efficace de photons uniques déclenchés, de polarisation bien définie. Nous avons mesuré la fonction d'autocorrélation temporelle en intensité qui met en évidence un dégroupement de photons presque parfait. Une telle source de photons uniques de haut flux possède des applications potentielles pour le traitement de l'information quantique.

Darquié, B.; Beugnon, J.; Jones, M. P. A.; Dingjan, J.; Sortais, Y.; Browaeys, A.; Messin, G.; Grangier, P.

2006-10-01

48

Readers of histone modifications  

Microsoft Academic Search

Histone modifications not only play important roles in regulating chromatin structure and nuclear processes but also can be passed to daughter cells as epigenetic marks. Accumulating evidence suggests that the key function of histone modifications is to signal for recruitment or activity of downstream effectors. Here, we discuss the latest discovery of histone-modification readers and how the modification language is

Miyong Yun; Jun Wu; Jerry L Workman; Bing Li

2011-01-01

49

Milton: A New, Unique Pallasite  

NASA Astrophysics Data System (ADS)

The Milton pallasite was found in Missouri in 2000. The chemistry of the olivine and metal phases, plus the oxygen isotope ratios of the olivines, differ significantly from other pallasites, making Milton unique.

Jones, R. H.; Wasson, J. T.; Larson, T.; Sharp, Z. D.

2003-03-01

50

The post anesthesia care unit: Unique contribution, unique risk  

Microsoft Academic Search

The environment in the postanesthesia care unit (PACU) is unique in the modern hospital. It was born of necessity and continues of necessity. The modern PACU has evolved from a simple room designed to house a single patient and a nurse to a modern, bustling room of great proportions. Today's PACU is an open ward, probably the only one left

J. Michael Badgwell; J MICHAELBADGWELL

1996-01-01

51

Fog Simulator System Modification.  

National Technical Information Service (NTIS)

The report deals with the modification of the daytime fog simulator system. In order to improve its effectiveness to realistically simulate actual fog, several changes have been incorporated into the unit. The fog simulator system and the modifications to...

A. Sussman

1973-01-01

52

Urticarial vasculitis: a unique presentation.  

PubMed

Urticarial vasculitis is a relatively rare diagnosis in a patient presenting with urticaria. The process is classically described as a generalized eruption, painful more so than pruritic, lasting longer than 24 hours. Two forms of urticarial vasculitis have been described: ahypocomplementemic form more commonly associated with systemic disease, and a normocomplementemic form that is generally limited to the skin. We report on a uniquely distributed vasculitic eruption restricted mainly to the anterior belt line area in a patient presenting with urticaria and intense pruritus. Urticarial vasculitis as a unique entity is reviewed along with its clinical and histopathologic presentation and the pharmacologic agents used for treatment. PMID:19373142

Stigall, Landon E; Sigmon, Justin R; Leicht, Stuart S

2009-05-01

53

Milton: A New, Unique Pallasite  

NASA Technical Reports Server (NTRS)

The Milton pallasite was found in Missouri, U.S.A. in October, 2000. It consists of a single stone that originally weighed approximately 2040 g. The chemistry of the olivine and metal phases, plus the oxygen isotope ratios of the olivines, differ significantly from other pallasites, making Milton unique. Unfortunately, the meteorite is heavily fractured and weathered.

Jones, R. H.; Wasson, J. T.; Larson, T.; Sharp, Z. D.

2003-01-01

54

Unique horizontal symmetry of leptons  

SciTech Connect

There is a group-theoretical connection between fermion mixing matrices and minimal horizontal symmetry groups. Applying this connection to the tribimaximal neutrino mixing matrix, we show that the minimal horizontal symmetry group for leptons is uniquely S{sub 4}, the permutation group of four objects.

Lam, C. S. [Department of Physics, McGill University, Montreal, Q.C., H3A 2T8 (Canada) and Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

2008-10-01

55

A unique course in anthropology.  

PubMed

The course in forensic anthropology presented at Florida State University is designed to train criminal investigators in the application of physical anthropological and archaeological techniques to the investigation of buried bodies. Modification of archaeological field techniques by experimentation using artificial graves allows the recovery of fragile and easy to overlook evidence and ensures the recovery of all possible material for analysis by the physical anthropologist. An introduction to physical anthropology enables the criminal investigator to effectively communicate his needs and understand the type of information required for adequate identification of remains by a physical anthropologist. PMID:998763

Morse, D; Stoutamire, J; Duncan, J

1976-11-01

56

Novel Modifications in RNA  

PubMed Central

The last several years have seen numerous reports of new chemical modifications for use in RNA. In addition, in that time period, we have seen the discovery of several previously unknown naturally occurring modifications that impart novel properties on the parent RNAs. In this review, we describe recent discoveries in these areas with a focus on RNA modifications that introduce spectroscopic tags, reactive handles, or new recognition properties.

Phelps, Kelly; Morris, Alexi; Beal, Peter A.

2012-01-01

57

Separable States with Unique Decompositions  

NASA Astrophysics Data System (ADS)

We search for faces of the convex set consisting of all separable states, which are affinely isomorphic to simplices, to get separable states with unique decompositions. In the two-qutrit case, we found that six product vectors spanning a five dimensional space give rise to a face isomorphic to the 5-dimensional simplex with six vertices, under a suitable linear independence assumption. If the partial conjugates of six product vectors also span a 5-dimensional space, then this face is inscribed in the face for PPT states whose boundary shares the fifteen 3-simplices on the boundary of the 5-simplex. The remaining boundary points consist of PPT entangled edge states of rank four. We also show that every edge state of rank four arises in this way. If the partial conjugates of the above six product vectors span a 6-dimensional space then we have a face isomorphic to 5-simplex, whose interior consists of separable states with unique decompositions, but with non-symmetric ranks. We also construct a face isomorphic to the 9-simplex. As applications, we give answers to questions in the literature Chen and Djokovi? (J Math Phys 54:022201, 2013) and Chen and Djokovi? (Commun Math Phys 323:241-284, 2013), and construct 3 ? 3PPT states of type (9,5). For the qubit-qudit cases with d ? 3, we also show that ( d + 1)-dimensional subspaces give rise to faces isomorphic to the d-simplices, in most cases.

Ha, Kil-Chan; Kye, Seung-Hyeok

2014-05-01

58

Modification of alternan by dextranase.  

PubMed

Alternan is a unique glucan with a backbone structure of alternating alpha-(1 --> 6) and alpha-(1 --> 3) linkages. Previously, we isolated strains of Penicillium sp. that modify native, high molecular weight alternan in a novel bioconversion process to a lower molecular weight form with solution viscosity properties similar to those of commercial gum arabic. The mechanism of this modification was unknown. Here, we report that these Penicillium sp. strains secrete dextranase during germination on alternan. Furthermore, alternan is modified in vitro by commercial dextranases, and dextranase-modified alternan appears to be identical to bioconversion-modified alternan. This is surprising, since alternan has long been considered to be resistant to dextranase. Results suggest that native alternan may have localized regions of consecutive alpha-(1 --> 6) linkages that serve as substrates for dextranase. Dextranase treatment of native alternan, particularly with GRAS enzymes, may have practical advantages for the production of modified alternan as a gum arabic substitute. PMID:18931826

Leathers, Timothy D; Nunnally, Melinda S; Côté, Gregory L

2009-02-01

59

Oxidative DNA modifications  

Microsoft Academic Search

Oxidative DNA modifications are frequent in mammalian DNA and have been suggested an important mechanism in carcinogenesis, diabetes and ageing. The foundations for this suggestion are:Evidence for the importance of oxidative DNA modifications in cancer development is: high levels of oxidative lesions in cancer tissue; highly conserved and specific DNA repair systems targeting oxidative lesions; high levels of oxidative DNA

Henrik E. Poulsen

2005-01-01

60

Permit application modifications  

SciTech Connect

This document contains the Permit Application Modifications for the Y-12 Industrial Landfill V site on the Oak Ridge Reservation. These modifications include the assessment of stability of the proposed Landfill V under static and loading conditions. Analyses performed include the general slope stability, veneer stability of the bottom liner and cover system, and a liquefaction potential assessment of the foundation soils.

NONE

1995-11-01

61

Histone onco-modifications  

Microsoft Academic Search

Post-translational modification of histones provides an important regulatory platform for processes such as gene expression, DNA replication and repair, chromosome condensation and segregation and apoptosis. Disruption of these processes has been linked to the multistep process of carcinogenesis. We review the aberrant covalent histone modifications observed in cancer, and discuss how these epigenetic changes, caused by alterations in histone-modifying enzymes,

J Füllgrabe; E Kavanagh; B Joseph

2011-01-01

62

Sordarin, an antifungal agent with a unique mode of action  

PubMed Central

Summary The sordarin family of compounds, characterized by a unique tetracyclic diterpene core including a norbornene system, inhibits protein synthesis in fungi by stabilizing the ribosome/EF2 complex. This mode of action is in contrast to typical antifungals, which target the cell membrane. This unusual bioactivity makes sordarin a promising candidate for the development of new fungicidal agents, and provided the motivation for extensive research. Three total syntheses (by the Kato, Mander and Narasaka groups), modifications of the glycosyl unit, and changes to the diterpene core (Cuevas and Ciufolini models) will also be discussed in this review.

2008-01-01

63

Wasatch Weather Modification Project.  

National Technical Information Service (NTIS)

The primary objective of the Wasatch Weather Modification Project is to 'assess the relative effectiveness and the practicability of selected procedures for increasing the water supply, from precipitation in the Wasatch Mountains, by cloud seeding.' A loc...

G. W. Reynolds

1969-01-01

64

Dobson Ozone Spectrophotometer Modification.  

National Technical Information Service (NTIS)

The paper describes modifications in the high-voltage power supply, the photomultiplier tube circuit, and amplifier, the electromechanical phase-sensitive rectifier and the optical wedge of the Dobson Ozone spectrophotometer. (Author)

W. D. Komhyr R. D. Grass

1972-01-01

65

Surface modification of solids  

SciTech Connect

The use of ion beam and pulsed laser processing is reviewed for the near-surface modification of a wide range of materials. The techniques of ion implantation doping, ion beam and laser mixing, and pulsed-laser annealing are stressed with particular emphasis on the nonequilibrium aspects of these processing techniques and on new materials properties which can result. Examples are presented illustrating the utility of these techniques for fundamental materials research as well as practical surface modifications.

Appleton, B.R.

1984-05-01

66

Tyrosine Modifications in Aging  

PubMed Central

Abstract Significance: The understanding of physiological and pathological processes involving protein oxidation, particularly under conditions of aging and oxidative stress, can be aided by proteomic identification of proteins that accumulate oxidative post-translational modifications only if these detected modifications are connected to functional consequences. The modification of tyrosine (Tyr) residues can elicit significant changes in protein structure and function, which, in some cases, may contribute to biological aging and age-related pathologies, such as atherosclerosis, neurodegeneration, and cataracts. Recent Advances: Studies characterizing proteins in which Tyr has been modified to 3-nitrotyrosine, 3,4-dihydroxyphenylalanine, 3,3?-dityrosine and other cross-links, or 3-chlorotyrosine are reviewed, with an emphasis on structural and functional consequences. Critical Issues: Distinguishing between inconsequential modifications and functionally significant ones requires careful biochemical and biophysical analysis of target proteins, as well as innovative methods for isolating the effects of the multiple modifications that often occur under oxidizing conditions. Future Directions: The labor-intensive task of isolating and characterizing individual modified proteins must continue, especially given the expanding list of known modifications. Emerging approaches, such as genetic and metabolic incorporation of unnatural amino acids, hold promise for additional focused studies of this kind. Antioxid. Redox Signal. 17, 1571–1579.

Feeney, Maria B.

2012-01-01

67

Modifications of gravity.  

PubMed

General relativity (GR) is a phenomenologically successful theory that rests on firm foundations, but has not been tested on cosmological scales. The deep mystery of dark energy (and possibly even the requirement of cold dark matter (CDM)) has increased the need for testing modifications to GR, as the inference of such otherwise undetected fluids depends crucially on the theory of gravity. Here, I discuss a general scheme for constructing consistent and covariant modifications to the Einstein equations. This framework is such that there is a clear connection between the modification and the underlying field content that produces it. I argue that this is mandatory for distinguishing modifications of gravity from conventional fluids. I give a non-trivial example, a simple metric-based modification of the fluctuation equations for which the background is exact ?CDM, but differs from it in the perturbations. I show how this can be generalized and solved in terms of two arbitrary functions. Finally, I discuss future prospects and directions of research. PMID:22084286

Skordis, Constantinos

2011-12-28

68

Social Aspects of Weather Modification  

Microsoft Academic Search

A description of the social context and citizen response to three weather modification projects provides an introduction to the discussion of a variety of social and economic issues related to planned weather modification. Various interest groups have markedly different perspectives on weather modification. Most persons subject to the consequences of weather modification have no opportunity to participate in the associated

J. Eugene Haas

1973-01-01

69

Surface modification of silica nanoparticles  

NASA Astrophysics Data System (ADS)

Surface modification of nanosized silica particles by polymer grafting is gaining attention. This can be attributed to the fact that it provides a unique opportunity to engineer the interfacial properties of these modified particles; at the same time the mechanical and thermal properties of the polymers can be improved. Controlled free radical polymerization is a versatile technique which affords control over molecular weight, molecular weight distribution, architecture and functionalities of the resulting polymer. Three commonly used controlled free radical polymerizations include nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP) and reversible addition fragmentation transfer (RAFT) polymerization. ATRP and RAFT polymerization were explored in order to modify the silica surface with well-defined polymer brushes. A novel click-functionalized RAFT chain transfer agent (RAFT CTA) was synthesized which opened up the possibility of using RAFT polymerization and click chemistry together in surface modification. Using this RAFT CTA, the surface of silica nanoparticles was modified with polystyrene and polyacrylamide brushes via the "grafting to" approach. Both tethered polystyrene and polyacrylamide chains were found in the brush regime. The combination of ATRP and click chemistry was also explored for surface modification. A combination of RAFT polymerization and click chemistry was also studied to modify the surface via the "grafting from" approach. Our strategy included the (1) "grafting from" approach for brush formation (2) facile click reaction to immobilize the RAFT agent (3) synthesis of R-supported chain transfer agent and (4) use of the more active trithiocarbonate RAFT agent. Grafting density obtained by this method was significantly higher than reported values in the literature. Polystyrene (PS) grafted silica nanoparticles were also prepared by a tandem process that simultaneously employs reversible addition fragmentation transfer (RAFT) polymerization and click chemistry. The click reaction doesn't interfere with RAFT polymerization. With a suitable choice of a Cu(I) catalyst, it is possible to perform both RAFT polymerization and click chemistry together. In a single pot procedure, azide-modified silica, an alkyne-functionalized RAFT agent and styrene were combined to produce the desired product. As deduced by thermal gravimetric and elemental analysis, the grafting density of PS on the silica in the tandem process was intermediate between the "grafting to" and "grafting from" techniques. Relative rates of RAFT polymerization and click reaction were altered to control grafting density. ATRP was also used to modify the surface of silica nanoparticles via the "grafting from" approach. The surfaces of silica with homopolymers and diblock copolymers brushes were modified using surface initiated ATRP. The polymer grafted silica particles were characterized by FT-IR, TGA, XPS and elemental analysis.

Ranjan, Rajesh

70

Noncovalent Chemical Modification of Graphene  

NASA Astrophysics Data System (ADS)

Low dimensional carbon allotropes presently provide an unparalleled platform to explore novel electronic properties, and with tremendous progress may one day supplant entrenched materials within the semiconductor industry. In order for graphene to continue on its extraordinary scientific and technological trajectories, many hurdles must be overcome such as reliable bandgap engineering, advances in processability, removal or mitigation of defects and so on. Noncovalent chemical modification of graphene offers a pathway to address many of these concerns and furthermore provides an opportunity to graft new functionality onto this unique material. In this work, the effects of noncovalent modification of graphene by simple polyaromatic molecules - rubrene and tetracene - are investigated. By exploiting ?-? interactions between the two highly conjugated systems, a simple approach to functionalize graphene devices has been developed. Optical and electron-beam lithography are used to fabricate graphene field effect transistors, which can be subsequently modified either in their entirety or in a site specific manner. In order to better understand the resulting graphene/rubrene structure, a suite of analytical tools has been employed. Raman spectroscopy and microscopy confirm the presence of the rubrene and spatially correlate observed electronic changes with surface modification while polarized Raman spectroscopy is used to investigate any long range order of rubrene on the graphene surface. Photoluminescence measurements show that rubrene emission is not quenched, and spectral analysis offers insight into rubrene film characteristics. Atomic force microscopy provides detailed information as to film thickness, and suggests that rubrene film morphology is largely disordered. Due to the simplicity of this functionalization procedure, a rubrene-based motif could be widely expanded allowing researchers to explore grafting new chemical moieties onto graphene and enabling new device opportunities. Transport measurements reveal the effects of rubrene on the graphene electronic properties. Modified devices display increased conductivity, a substantial shift in Dirac point and a moderate decrease in carrier mobility, all of which are consistent with an electronic doping mechanism whereby the rubrene acts as a hole dopant. Preliminary photoresponse measurements suggest that this graphene-molecular hybrid could act as a potential photodetector.

Bobak, Julia

71

Synthesis and chemical modification of carbon nanostructures for materials applications  

Microsoft Academic Search

This dissertation explores the structure, chemical reactivities, electromagnetic response, and materials properties of various carbon nanostructures, including single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphite, and graphene nanoribbons (GNRs). Efficient production and modification of these unique structures, each with their own distinct properties, will make them more accessible for applications in electronics, materials, and biology. A method is reported

Amanda Lynn Higginbotham

2009-01-01

72

Biologically Active Polymers: Modification and Antimicrobial Activity of Chitosan Derivatives  

Microsoft Academic Search

The principal derivative of chitin is chitosan, which is obtained by deacetylation of chitin. Chemical modification of synthetic and natural polymers is a convenient way to obtain materials with unique chemical and physical properties. Chitosan has an amino group at C-2 which is important because amino groups are nucleophilic and readily react with electrophilic reagents. Chitosan modified under mild conditions

El-Refaie Kenawy; F. Imam Abdel-Hay; Ahmed Abou El-Magd; Yehia Mahmoud

2005-01-01

73

Diet Modification for Hyperlipidemia  

PubMed Central

Hyperlipidemia is a major risk factor associated with cardiovascular disease. Dietary modification is effective in achieving and maintaining improved serum lipid levels. Nutritional care provided by a dietitian includes individual dietary and lifestyle assessment, formulating an appropriate dietary regimen, education, and follow-up assessments.

Mann, Heather D.; Piotrowski, Pamela

1992-01-01

74

Microdensitometer electronics modification  

NASA Technical Reports Server (NTRS)

Minor modifications of electronic components in the PDS 1010A microdensitometer are discussed. The operational requirements and performance limitations of the PDS are noted. Replacement of the photomultiplier and front-end analog circuitry significantly improved the photometric performance of the PDS. The improvement in density repeatability is marked, and the permissible density slew speed is greatly increased.

Hewitt, A. V.

1984-01-01

75

Instructional Improvement: Behavior Modification.  

ERIC Educational Resources Information Center

Sixteen papers are provided. B. F. Skinner discusses the arrangement of contingencies for learning: Lloyd Homme describes behavioral engineering; and Frank Hewett considers behavior modification in special education. Also treated are experimental education by Norris Haring, program evaluation by Arthur Lumsdaine, and administration of special…

Haring, Norris G.; Hayden, Alice H.

76

Surface modification technologies II  

SciTech Connect

The conference presented in this book covered chemical vapor deposition, aerospace coatings, lasers, characterization of surfaces and plasma and ion beam techniques. The papers presented include coatings for high temperature corrosion in aero and industrial gas turbines and the use of high power lasers in surface modifications.

Sudarshan, T.S. (Materials Modifications, Inc., Falls Church, VA (US)); Bhat, D.G. (GTE Valenite Corp., Troy, MI (US))

1989-01-01

77

BRBF response modification factor  

Microsoft Academic Search

In this paper, overstrength, ductility and response modification factor of Buckling Restrained Braced frames were evaluated. To do so, buildings with various stories and different bracing configuration including diagonal, split X, chevron (V and Inverted V) bracings were considered. Static pushover analysis, nonlinear incremental dynamic analysis and linear dynamic analysis have been performed using Opensees software. The effects of some

B. Asgarian; H. R. Shokrgozar

2009-01-01

78

Benign Weather Modification.  

National Technical Information Service (NTIS)

Weather modification is a technology once embraced by the United States (US) military as a tool to help both wartime and peacetime missions. However, interest in the ability to modify weather has waned over recent years and is now nearly nonexistent. This...

B. B. Coble

1997-01-01

79

Benign Weather Modification.  

National Technical Information Service (NTIS)

Weather modification is a technology once embraced by the U.S. military as a tool to help both wartime and peacetime missions. However, interest in the ability to modify weather has waned over recent years and is now nearly non-existent. This study examin...

B. E. Coble

1996-01-01

80

Unique modification of adenine in genomic DNA of the marine cyanobacterium Trichodesmium sp. strain NIBB 1067.  

PubMed Central

The genomic DNA of the marine nonheterocystous nitrogen-fixing cyanobacterium Trichodesmium sp. strain NIBB 1067 was found to be highly resistant to DNA restriction endonucleases. The DNA was digested extensively by the restriction enzyme DpnI, which requires adenine methylation for activity. The DNA composition, determined by high-performance liquid chromatography (HPLC), was found to be 69% AT. Surprisingly, it was found that a modified adenine which was not methylated at the usual N6 position was present and made up 4.7 mol% of the nucleosides in Trichodesmium DNA (15 mol% of deoxyadenosine). In order for adenine residues to be modified at this many positions, there must be many modifying enzymes or at least one of the modifying enzymes must have a degenerate recognition site. The reason(s) for this extensive methylation has not yet been determined but may have implications for the ecological success of this microorganism in nature. Images FIG. 1 FIG. 2

Zehr, J P; Ohki, K; Fujita, Y; Landry, D

1991-01-01

81

A Framework of Authentic Post-Issuance Program Modification for Multi-Application Smart Cards  

Microsoft Academic Search

Authentic program modification is very important for a multi-application smart card system since ap- plications in the system are realized after the is- suance of the smart card. In this paper, we propose a framework for such authentic program modification. In our framework, before issuing a smart card to an individual, the card issuer stores a unique long bit string

Mohammad Mesbah Uddin; Salahuddin Muhammad Salim Zabir; Yasunobu Nohara; Hiroto Yasuura

2008-01-01

82

Electron capture dissociation mass spectrometry in characterization of post-translational modifications  

Microsoft Academic Search

Electron capture dissociation (ECD) represents a significant advance in tandem mass spectrometry for the identification and characterization of post-translational modifications (PTMs) of polypeptides. In comparison with the conventional fragmentation techniques, such as collisionally induced dissociation and infrared multi-photon dissociation, ECD provides more extensive sequence fragments, while allowing the labile modifications to remain intact during backbone fragmentation. This unique attribute offers

Ray. Bakhtiar; Ziqiang Guan

2005-01-01

83

Soviet Developments in Weather Modification, Climate Modification, and Climatology.  

National Technical Information Service (NTIS)

This report focuses on Soviet developments in weather modification, climate modification, and climatology during the period from late 1973 through mid-1975. Current Soviet work in solar meteorology and laser applications in atmospheric sounding are also s...

G. S. Gordon

1975-01-01

84

Constructing Dense Graphs with Unique Hamiltonian Cycles  

ERIC Educational Resources Information Center

It is not difficult to construct dense graphs containing Hamiltonian cycles, but it is difficult to generate dense graphs that are guaranteed to contain a unique Hamiltonian cycle. This article presents an algorithm for generating arbitrarily large simple graphs containing "unique" Hamiltonian cycles. These graphs can be turned into dense graphs…

Lynch, Mark A. M.

2012-01-01

85

Some Graphs Containing Unique Hamiltonian Cycles  

ERIC Educational Resources Information Center

In this paper, two classes of graphs of arbitrary order are described which contain unique Hamiltonian cycles. All the graphs have mean vertex degree greater than one quarter the order of the graph. The Hamiltonian cycles are detailed, their uniqueness proved and simple rules for the construction of the adjacency matrix of the graphs are given.…

Lynch, Mark A. M.

2002-01-01

86

Estimation of Non-Unique Quantiles.  

National Technical Information Service (NTIS)

The paper is concerned with consistent estimates of a quantile of a distribution function when the quantile is not unique. To be more precise, since the quantile is assumed not to be unique, the authors are concerned with obtaining a consistent estimate o...

D. Eeldman H. G. Tucker

1965-01-01

87

Unique specification of yang-mills solutions  

Microsoft Academic Search

Screened time-independent cylindrically-symmetric solutions of Yang-Mills equations are given which show that the source does not uniquely determine the field. However, these particular solutions suggest a natural way of uniquely specifying solutions in terms of a physical realization of a symmetry group.

William B. Campbell; David W. Joseph; Thomas A. Morgan

1980-01-01

88

PES fabric plasma modification  

NASA Astrophysics Data System (ADS)

Polyester ranks the upper position in the world fiber production — nearly 54% of the total production of synthetic fibers. Troubles connected with minimizing of the textile hydrophobicity are usually being solved by the textile fibers’ surface chemical modification, but from ecological point of view modification of fabric with low temperature plasma is superior to classical chemical wet processes. Application of various plasmas for PES treatment has been already described. To compare the effectiveness of different plasma sources we performed a series of experiment both in RF and MW plasmas. For working gas nitrogen, oxygen and their mixtures were employed. Internal plasma control was provided by measurement of optical emission spectra. The hydrophilicity degree was determined by the drop test. Paper discusses optimal conditions of the PES fabric plasma treatment.

Vatu?a, T.; Špatenka, P.; Píchal, J.; Koller, J.; Aubrecht, L.; Wiener, J.

2004-03-01

89

Xyloglucan in cellulose modification  

Microsoft Academic Search

Xyloglucans are the principal polysaccharides coating and crosslinking cellulose microfibrills in the majority of land plants.\\u000a This review summarizes current knowledge of xyloglucan structures, solution properties, and the mechanism of interaction of\\u000a xyloglucans with cellulose. This knowledge base forms the platform for new biomimetic methods of cellulose surface modification\\u000a with applications within the fields of textile manufacture, papermaking, and materials

Qi Zhou; Mark W. Rutland; Tuula T. Teeri; Harry Brumer

2007-01-01

90

Oxidative DNA modifications.  

PubMed

Oxidative DNA modifications are frequent in mammalian DNA and have been suggested an important mechanism in carcinogenesis, diabetes and ageing. The foundations for this suggestion are: Evidence for the importance of oxidative DNA modifications in cancer development is: high levels of oxidative lesions in cancer tissue; highly conserved and specific DNA repair systems targeting oxidative lesions; high levels of oxidative DNA lesions in oxidative DNA repair knock-out animals; defective repair of oxidative lesions in cancer-prone progeria syndromes; reduced cancer incidence in populations with high dietary antioxidant intake; and increased oxidative stress to DNA in tobacco smokers. Conflicting evidence for a relation between oxidative stress to DNA and cancer is: disagreement about the true levels and occurrence of the oxidative lesions in vivo; failure to identify the localization of oxidative lesions in important genes, e.g. tumor suppressor and oncogenes; lack of evidence that the oxidative lesions induce mutations in vivo; no cancer development in animals knocked-out for specific DNA repair enzymes in spite of high tissue levels of oxidative lesions; and unchanged cancer rates after antioxidant interventions in large clinical controlled and randomized trials. The rate of DNA oxidation has been estimated from urinary excretion of repair products and it is evident that if these lesions were not repaired, a large part of DNA would be oxidized to a degree not compatible with living. The methodologies by which oxidative DNA modifications are measured cover a wide and different range, advantages and disadvantages will be presented. One particular problem is artificial oxidation, and methods to prevent such artifacts will be presented together with results from a large interlaboratory standardization program. The methodology by which the lesions can be measured is complicated and prone to artifacts during DNA isolation, digestion, derivatization and maybe even during the separation procedure proper prior to detection. A large effort from 20+ laboratories supported by a grant from the EU has reduced artifacts considerably and work towards interlaboratory standardization of the methodology is in progress. The presently agreed "normal" levels of the most frequent known lesion 8-oxodG is about 5 per million dG's in DNA. A comprehensive evaluation of the evidence, from chemistry to clinical and epidemiological trials, linking oxidative modifications to cancer will be given. Finally, an estimate of the quantitative role oxidative DNA modifications play among the multiplicity of other insults is given. While there is no question that all of these oxidative mechanisms do exist, quantitative data on their importance for the human situation do not exist. Prospective human studies that can provide such quantitative data on different mechanisms are underway. PMID:16092724

Poulsen, Henrik E

2005-07-01

91

Weather Modification: Finding Common Ground  

Microsoft Academic Search

Research and operational approaches to weather modification expressed in the National Research Council's 2003 report on ``Critical Issues in Weather Modification Research'' and in the Weather Modification Association's response to that report form the basis for this discussion. There is agreement that advances in the past few decades over a broad front of understanding physical processes and in technology have

Michael Garstang; Roelof Bruintjes; Robert Serafin; Harold Orville; Bruce Boe; William Cotton; Joseph Warburton

2005-01-01

92

What's in a name? Our false uniqueness!  

PubMed

The current study investigated our perception of first names. In Study 1, participants estimated their own first name to be less frequent compared with estimates from yoked controls. The first name uniqueness effect was seen for both rare and common names, and male and female names. The uniqueness bias was not due to differential encoding of variegated and shortened names, such as different versions of the name Caitlyn. Study 2 established that rarer names are preferred, and, that when we contemplate a name change, we often consider rare names. Several theoretical explanations for a general name uniqueness effect are proposed. PMID:23082927

Kulig, John W

2013-03-01

93

On Annihilatingly Uniqueness of Directed Windmills  

Microsoft Academic Search

Let G be a digraph with n vertices and A(G) be its adjacency matrix. A monic polynomial f(x) of degree at most n is called an annihilating polynomial of G if f(A(G)) = 0. G is said to be annihilatingly unique if it possesses a unique annihilating polynomial. In this paper, the directed windmill M3(r) is defined and we study

C. S. Gan; V. C. Koo

94

Modularity, comparative cognition and human uniqueness.  

PubMed

Darwin's claim 'that the difference in mind between man and the higher animals … is certainly one of degree and not of kind' is at the core of the comparative study of cognition. Recent research provides unprecedented support for Darwin's claim as well as new reasons to question it, stimulating new theories of human cognitive uniqueness. This article compares and evaluates approaches to such theories. Some prominent theories propose sweeping domain-general characterizations of the difference in cognitive capabilities and/or mechanisms between adult humans and other animals. Dual-process theories for some cognitive domains propose that adult human cognition shares simple basic processes with that of other animals while additionally including slower-developing and more explicit uniquely human processes. These theories are consistent with a modular account of cognition and the 'core knowledge' account of children's cognitive development. A complementary proposal is that human infants have unique social and/or cognitive adaptations for uniquely human learning. A view of human cognitive architecture as a mosaic of unique and species-general modular and domain-general processes together with a focus on uniquely human developmental mechanisms is consistent with modern evolutionary-developmental biology and suggests new questions for comparative research. PMID:22927578

Shettleworth, Sara J

2012-10-01

95

Soviet ionospheric modification research  

SciTech Connect

Soviet published literature in ionospheric modification research by high-power radio waves is assessed, including an evaluation of its impact on and applications to future remote-sensing and telecommunications systems. This assessment is organized to place equal emphasis on basic research activities, designed to investigate both the natural geophysical environment and fundamental plasma physics; advanced research programs, such as those studying artificial ionization processes and oblique high-power radio propagation and practical system applications and operational limitations addressed by this research. The assessment indicates that the Soviet Union sustains high-quality theoretical and experimental research programs in ionospheric modification, with a breadth and level of effort greatly exceeding comparable Western programs. Soviet theoretical research tends to be analytical and intuitive, as compared to the Western emphasis on numerical simulation techniques. The Soviet experimental approach is less exploratory, designed principally to confirm theoretical predictions. Although limited by inferior diagnostic capabilities, Soviet experimental facilities are more numerous, operate on a more regular basis, and transmit radio wave powers exceeding those os Western facilities. Because of its broad scope of activity, the Soviet Union is better poised to quickly exploit new technologies and system applications as they are developed. This panel has identified several key areas of Soviet research activity and emerging technology that may offer long-term opportunities for remote-sensing and telecommunications advantages. However, we have found no results that suggest imminent breakthrough discoveries in these fields.

Duncan, L.M.; Carlson, H.C.; Djuth, F.T.; Fejer, J.A.; Gerson, N.C.; Hagfors, T.; Newman, D.B. Jr.; Showen, R.L.

1988-07-01

96

Spine Remodeling and Synaptic Modification  

Microsoft Academic Search

The majority of excitatory communication occurs at dendritic spines, and spine modifications accompany synaptic modifications\\u000a under both physiological and pathological conditions. Although it is increasingly clear that spine remodeling is required\\u000a for synaptic modification, the exact functions and underlying molecular mechanisms remain unclear. Here, we review recent\\u000a progress on this topic and discuss the functions of spine remodeling in a

Xiao-bin Wang; Qiang Zhou

2010-01-01

97

On uniqueness for frictional contact rate problems  

NASA Astrophysics Data System (ADS)

A linear elastic solid having part of the boundary in unilateral frictional contact witha stiffer constraint is considered. Bifurcations of the quasistatic velocity problem are analyzed,making use of methods developed for elastoplasticity. An exclusion principle for bifurcation isproposed which is similar, in essence, to the well-known exclusion principle given by Hill, 1958. Sufficient conditions for uniqueness are given for a broad class of contactconstitutive equations. The uniqueness criteria are based on the introduction of linear comparisoninterfaces defined both where the contact rate constitutive equation are piece-wise incrementallylinear and where these are thoroughly nonlinear. Structural examples are proposed which giveevidence to the applicability of the exclusion criteria.

Radi, E.; Bigoni, D.; Tralli, A.

1999-02-01

98

How unique is the human neocortex?  

PubMed

The human cerebral cortex is generally considered the most complex organ, and is the structure that we hold responsible for the repertoire of behavior that distinguishes us from our closest living and extinct relatives. At a recent Company of Biologists Workshop, 'Evolution of the Human Neocortex: How Unique Are We?' held in September 2013, researchers considered new information from the fields of developmental biology, genetics, genomics, molecular biology and ethology to understand unique features of the human cerebral cortex and their developmental and evolutionary origin. PMID:24346696

Molnár, Zoltán; Pollen, Alex

2014-01-01

99

Relationship between uniqueness and competition ability  

NASA Astrophysics Data System (ADS)

In our previous paper (Feng A X, Xu X L, He D R 2009 Chin. Phys. Lett. 26 058901) we proposed quantitative definitions of uniqueness and competition ability. Their trivial linear relationship was analytically discussed. In this letter, we present analytical discussion on the more interesting anomalous cases. The analytical result shows that, instead of the trivial linear relationship, the relationship between uniqueness and competition ability obeys a power law. The competition between Beijing restaurants is taken as an example. The empirical investigation results show a strong support to the analytical conclusion.

Liu, Ai-Fen; Xu, Xiu-Lian; He, Da-Ren

2010-03-01

100

Photons uniques indiscernables à partir d'une boîte quantique unique dans un cristal photonique  

NASA Astrophysics Data System (ADS)

Nous avons développé et caractérisé une source de photons uniques basée sur l'émission spontanée d'une boîte quantique unique insérée dans une cavité à bande interdite photonique bidimensionnelle. Ce système nous a d'abord permis de produire des photons uniques, puis des photons uniques indiscernables avec une indiscernabilité supérieure à 70%. L'observation de l'indiscernabilité des photons, impossible sans un raccourcissement important de la durée de vie, met en évidence un effet Purcell supérieur à 25 dans ce système.

Laurent, S.; Varoutsis, S.; Le Gratiet, L.; Lemaître, A.; Sagnes, I.; Raineri, F.; Levenson, A.; Robert-Philip, I.; Abram, I.

2006-10-01

101

Structural Modification of Nanocrystalline Ceria by Ion Beams  

SciTech Connect

Using energetic ions, we have demonstrated effective modification of grain size in nanocrystalline ceria in the critical region for controlling exceptional size-dependent electronicionic conductivity. The grain size increases and follows an exponential law as a function of ion fluence that increases with temperature, while the cubic phase is stable under the irradiation. The unique self-healing response of radiation damage at grain boundaries is utilized to control the grain size at the nanoscale.

Zhang, Yanwen; Edmondson, Philip D.; Varga, Tamas; Moll, Sandra J.; Namavar, Fereydoon; Lan, Chune; Weber, William J.

2011-05-25

102

Surface modification of a microcellular porous solid: carbon foam  

Microsoft Academic Search

Microcellular solids such as carbon foams offer unique advantages over traditional solids in many applications. However, since these structures are 80–90% porous, they have a high interface\\/volume ratio, and surface driven properties such as atmospheric tolerance and bond formation with the matrix material are crucial for applicability. This calls for controlled surface modification techniques that can tailor surface-related properties without

S. M. Mukhopadhyay; R. V. Pulikollu; A. K. Roy

2004-01-01

103

Permanence, Durability and Unique Properties of Hanji  

Microsoft Academic Search

This research project presents new information about the permanence and durability of contemporary Korean handmade papers, explains the particular methods of traditional hanji papermakers while introducing the possibilities of utilizing the products of Korean papermills in conservation. Traditional Korean papermaking uses a unique technique, known as webal, to form a sheet which distributes fibers evenly in both directions theoretically resulting

MINAH SONG; JESSE MUNN

104

LCA ? Unique and Controversial Case Studies  

EPA Science Inventory

This session will focus on case studies and applications that have a unique or controversial aspect. Some of the most recent topics that seem to have significant interest include: LCA-based product declarations, LCA-based standards, LCA-based labels, alternative energy, agricul...

105

A Unique Approach to Phlebotomy Instruction.  

ERIC Educational Resources Information Center

Unique characteristics of a continuing education course in phlebotomy offered through Tarrant County Junior College in Forth Worth, Texas, are described. The course was created to address the lack of theoretical knowledge in the hospital-trained phlebotomist. The first course was offered in July 1979 on a noncredit basis for 2 nights a week for 4…

Brock, Ann; Kelly, Mary Lou

106

Is mankind unique in the Galaxy?  

Microsoft Academic Search

There is a relation between questions regarding the uniqueness of mankind in the Galaxy and the 'Fermi Paradox'. It has appeared to Fermi that the eventual controlled command of astronomical quantities of energy, and the ability for mankind to head out into the universe was only a matter of time. On the other hand, he reasoned that a large number

A. R. Martin; A. Bond

1984-01-01

107

Latent Variable Models of Need for Uniqueness.  

ERIC Educational Resources Information Center

Confirmatory factor analysis evaluated three a priori latent variable models of responses to the Need for Uniqueness Scale completed by 552 undergraduates. An oblique three-factor model best accounted for item commonality. Additional analysis suggests a model with loadings on four modestly correlated factors to explain the scale's latent…

Tepper, Kelly; Hoyle, Rick H.

1996-01-01

108

Unique test capabilities at Sandia National Laboratories  

Microsoft Academic Search

A comprehensive testing capability has evolved at Sandia National Laboratories over the last three decades. This capability is primarily dedicated to obtaining test response data to substantiate analytical methods employed at the Laboratories. Unique instrumentation and data transmission techniques have been developed to recover test data. Emphasis has been placed on expeditious processing of test results for correlation with the

J. C. Bushnell; D. C. Bickel

1981-01-01

109

Global Unique ID Framework for Copyright Material  

Microsoft Academic Search

The digital content distribution is becoming more complex and diverse with related issues like privacy of personal information and Internet shopping. One of the problems is the missing link of URL, and the other problem is interaction of copyrighted material and Internet, where everyhing is copy free. In this paper, we introduce a framework in which a global unique identifier

LATE Florence; Shinji KONO; Akira KAMIZATO

2005-01-01

110

Hitler and the Uniqueness of Nazism  

Microsoft Academic Search

Though nazism can be located as a form of fascism or type of totalitarianism, these generic concepts inadequately account for what was singular about a regime which unleashed such devastating inhumanity — a terrible war of annihilation and the worst genocide the world has yet experienced. So this article suggests an answer located in a unique combination of forces embodied

Ian Kershaw

2004-01-01

111

Unique doubly connected left ventricular diverticulum.  

PubMed

This case report describes a unique form of a left ventricular diverticulum in a 17-year-old patient.Echocardiography, angiography, and magnetic resonance imaging including virtual endoscopy complete a detailed picture of the size and texture of a diverticulum, as well as the localisation of the two connections into the left ventricle. PMID:22924172

Nagel, Bert; Sorantin, Erich; Gamillscheg, Andreas

2012-08-01

112

Existence, uniqueness and stability of positive periodic solution for a nonlinear prey-competition model with delays  

NASA Astrophysics Data System (ADS)

A nonlinear periodic predator-prey model with m-preys and (n-m)-predators and delays is proposed in this paper, which can be seen as the modification of the traditional Lotka-Volterra prey-competition model. Sufficient conditions which guarantee the existence of a unique globally attractive positive periodic solution of the system are obtained.

Chen, Fengde; Xie, Xiangdong; Shi, Jinlin

2006-10-01

113

Autoantibodies to Posttranslational Modifications in Rheumatoid Arthritis  

PubMed Central

Autoantibodies have been associated with human pathologies for a long time, particularly with autoimmune diseases (AIDs). Rheumatoid factor (RF) is known since the late 1930s to be associated with rheumatoid arthritis (RA). The discovery of anticitrullinated protein antibodies in the last century has changed this and other posttranslational modifications (PTM) relevant to RA have since been described. Such PTM introduce neoepitopes in proteins that can generate novel autoantibody specificities. The recent recognition of these novel specificities in RA provides a unique opportunity to understand human B-cell development in vivo. In this paper, we will review the three of the main classes of PTMs already associated with RA: citrullination, carbamylation, and oxidation. With the advancement of research methodologies it should be expected that other autoantibodies against PTM proteins could be discovered in patients with autoimmune diseases. Many of such autoantibodies may provide significant biomarker potential.

Burska, Agata N.; Hunt, Laura; Strollo, Rocky; Ryan, Brent J.; Vital, Ed; Nissim, Ahuva; Winyard, Paul G.; Emery, Paul; Ponchel, Frederique

2014-01-01

114

Epigenetic modifications as therapeutic targets  

Microsoft Academic Search

Epigenetic modifications work in concert with genetic mechanisms to regulate transcriptional activity in normal tissues and are often dysregulated in disease. Although they are somatically heritable, modifications of DNA and histones are also reversible, making them good targets for therapeutic intervention. Epigenetic changes often precede disease pathology, making them valuable diagnostic indicators for disease risk or prognostic indicators for disease

Theresa K Kelly; Daniel D De Carvalho; Peter A Jones

2010-01-01

115

Body Modification and Suicidal Behavior  

ERIC Educational Resources Information Center

In a large sample of individuals who belong to a website for body modification, having body modifications (e.g., piercings, tattoos, scarification and surgical procedures) was associated with a higher incidence of prior suicidality (i.e., suicidal ideation and attempted suicide). However, controls for self-reported depression weakened the strength…

Hicinbothem, Julie; Gonsalves, Sonia; Lester, David

2006-01-01

116

Posttranscriptional modification of tRNA in thermophilic archaea (Archaebacteria).  

PubMed

Nucleoside modification has been studied in unfractionated tRNA from 11 thermophilic archaea (archaebacteria), including phylogenetically diverse representatives of thermophilic methanogens and sulfur-metabolizing hyperthermophiles which grow optimally in the temperature range of 56 (Thermoplasma acidophilum) to 105 degrees C (Pyrodictium occultum), and for comparison from the most thermophilic bacterium (eubacterium) known, Thermotoga maritima (80 degrees C). Nine nucleosides are found to be unique to the archaea, six of which are structurally novel in being modified both in the base and by methylation in ribose and occur primarily in tRNA from the extreme thermophiles in the Crenarchaeota of the archaeal phylogenetic tree. 2-Thiothymine occurs in tRNA from Thermococcus sp., and constitutes the only known occurrence of the thymine moiety in archaeal RNA, in contrast to its near-ubiquitous presence in tRNA from bacteria and eukarya. A total of 33 modified nucleosides are rigorously characterized in archaeal tRNA in the present study, demonstrating that the structural range of posttranscriptional modifications in archaeal tRNA is more extensive than previously known. From a phylogenetic standpoint, certain tRNA modifications occur in the archaea which are otherwise unique to either the bacterial or eukaryal domain, although the overall patterns of modification are more typical of eukaryotes than bacteria. PMID:1708763

Edmonds, C G; Crain, P F; Gupta, R; Hashizume, T; Hocart, C H; Kowalak, J A; Pomerantz, S C; Stetter, K O; McCloskey, J A

1991-05-01

117

Conformation Effects of Base Modification on the Anticodon Stem–Loop of Bacillus subtilis tRNA Tyr  

Microsoft Academic Search

tRNA molecules contain 93 chemically unique nucleotide base modifications that expand the chemical and biophysical diversity of RNA and contribute to the overall fitness of the cell. Nucleotide modifications of tRNA confer fidelity and efficiency to translation and are important in tRNA-dependent RNA-mediated regulatory processes. The three-dimensional structure of the anticodon is crucial to tRNA–mRNA specificity, and the diverse modifications

Andria P. Denmon; Jiachen Wang; Edward P. Nikonowicz

2011-01-01

118

Unique device identification system. Final rule.  

PubMed

The Food and Drug Administration (FDA) is issuing a final rule to establish a system to adequately identify devices through distribution and use. This rule requires the label of medical devices to include a unique device identifier (UDI), except where the rule provides for an exception or alternative placement. The labeler must submit product information concerning devices to FDA's Global Unique Device Identification Database (GUDID), unless subject to an exception or alternative. The system established by this rule requires the label and device package of each medical device to include a UDI and requires that each UDI be provided in a plain-text version and in a form that uses automatic identification and data capture (AIDC) technology. The UDI will be required to be directly marked on the device itself if the device is intended to be used more than once and intended to be reprocessed before each use. PMID:24066364

2013-09-24

119

Lightning injuries. A unique treatment challenge.  

PubMed

Care of victims of lightning injury is a unique challenge rarely encountered in most clinical practices. Victims may present without signs or symptoms or, conversely, may present in cardiac arrest. Many have chronic, debilitating sequelae. Physicians caring for these patients either in the field or in the emergency department should be prepared to institute aggressive management techniques. An understanding of lightning physics and injury patterns prevents costly and inappropriate diagnostic tests and treatment. PMID:2726639

Ghezzi, K T

1989-06-01

120

Unique nature of hydroplant complicates design  

SciTech Connect

This article describes the unique nature of the Niagara Power Project as it affected upgrading of the Robert Moses powerplant and operation of the powerplant and pumped storage facility. To be taken into account are the variable flow of the Niagara River, treaties regarding division of river flow between Canada and USA and maintenance of river flow over the falls, and the level of Lake Erie.

Not Available

1990-01-01

121

Surface modification of bioceramics  

NASA Astrophysics Data System (ADS)

Hydroxyapatite [Ca10(PO4)6(OH)2, HAp] is a major inorganic component of bone and teeth tissues and has the excellent biocompatibility and high osteoconductivity. The interactions between HAp and protein or cell have been studied. The HAp related bioceramics such as bone substitute, coating substance of metal implants, inorganic-polymer composites, and cell culture. We described two methods; (1) surface modification of HAp using organosilane; (2) fabrication of HAp ultra-thin layer on gold surface for protein adsorption analyzed with QCM-D technique. The interfacial interaction between collagen and HAp in a nano-region was controlled by depositing the organosilane of n-octadecyltrimethoxysilane (ODS: -CH3) or aminopropyltriethoxysilane (APTS: -NH2) with a chemical vapor deposition method. The morphologies of collagen adsorbed on the surfaces of HAp and HAp deposited with APTS were similar, however that of the surface with ODS was apparently different, due to the hydrophobic interaction between the organic head group of -CH3 and residual groups of collagen. We present a method for coating gold quartz crystal microbalance with dissipation (QCM-D) sensor with ultra-thin layer of hydroxyapatite nanocrystals evenly covering and tightly bound to the surface. The hydroxyapatite sensor operated in liquid with high stability and sensitivity. The in-situ adsorption mechanism and conformational change of fibrinogen on gold, titanium and hydroxyapatite surfaces were investigated by QCM-D technique and Fourier-transform infrared spectroscopy. The study indicates that the hydroxyapatite sensor is applicable for qualitative and conformational analysis of protein adsorption.

Monkawa, Akira

122

Unique test capabilities at Sandia National Laboratories  

SciTech Connect

A comprehensive testing capability has evolved at Sandia National Laboratories over the last three decades. This capability is primarily dedicated to obtaining test response data to substantiate analytical methods employed at the Laboratories. Unique instrumentation and data transmission techniques have been developed to recover test data. Emphasis has been placed on expeditious processing of test results for correlation with the analytical processes. Numerous facilities address the general environments of acceleration, climate, shock, and vibration. Nondestructive testing includes acoustic emission detection, laser holography, ultrasonics, and radiography. More specific testing exists in the fields of aerodynamics, materials characterization, radiation effects, and energy research. Much of the capability is classical and can be found with degrees of similarity at other laboratories. However, there are certain unique testing capabilities that have been developed to satisfy special requirements. The unique testing facilities described include: rocket sled tracks for ballistics tests and impact tests; aerial cable facilities for free-drop tests of payloads up to 3000 lb from heights up to 600 ft.; explosives testing facilities; large centrifuges; equipment for simulating heating conditions such as reentry heating; a lighting simulator; and an electromagnetic environment simulator. (LCL)

Bushnell, J.C.; Bickel, D.C.

1981-05-01

123

Unique Aspects of Herbal Whole System Research  

PubMed Central

Introduction Whole systems of healthcare offer unique methodological and theoretical challenges for researchers. Herbalism has its own set of methodological and philosophical research issues, which are beyond those presented for whole system research, in general. Methods An International Society for Complementary Medicine Research (ISCMR) workshop was presented on, “Challenges in Herbal Whole Systems Research”. Starting from a definition of herbalism the most important challenges to herbal whole system research (HWSR) were elicited with inputs from both the workshop presenters and the audience. Results Five major challenges unique to herbal whole systems research were identified: (1) Defining herbalists and herbalism; (2) role of natural products industry in herbal research; (3) designing placebos and delivering active herbal treatments as are given by herbalists; (4) researching the herb as a living entity; and (5) designing trials to investigate and develop multi-component herbal therapies. Conclusions To design studies of herbalism requires unique methods and theoretical frameworks. Solutions to these methodological challenges need to be addressed to conduct research that examines herbal systems of medicine versus conducting trials on individual herbs given out of their original therapeutic context.

Zick, Suzanna M.; Schwabl, Herbert; Flower, Andrew; Lac, Dip; Chakraborty, Bibhas; Hirschkorn, Kristine

2009-01-01

124

A Unique Origin for Mojave Crater?  

NASA Astrophysics Data System (ADS)

Williams et al (LPSC 2004; see also Kerr, Science vol. 304, 196 ) recently reported the discovery of a spectacularly eroded, apparently water-carved impact crater on Mars. The ~60 km diameter crater, dubbed "Mojave Crater" for the resemblance of its alluvial fans to alluvial fans seen on Earth, is located on Xanthe Terra, Mars. The crater is rated as late Hesperian or Amazonian, meaning that the impact took place some time in the past 3.5 billion years; there is some evidence that it is not extraordinarily young. Yet the crater seems unique for its size. This crater, and to present knowledge this crater alone, is the obvious source of its own precipitation. Impact by a live, ice-rich comet may provide a unique origin for this unique crater. Impacts by live comets are surprisingly rare in the inner solar system. To make a 60 km crater on Mars requires either a ~6 km diameter nearly isotropic comet (NIC), or an ~10 km diameter Jupiter-family comet (JFC). NICs strike Mars about 3 times in 10 billion if they pass its orbit. The latter happens about 6 times per decade for NICs bigger than 6 km, so that at current rates a NIC makes a 60 km crater on Mars about once every 5 billion years. The typical Mars-crossing JFCs actually hits Mars at a rate of about 8e-11 per comet per year. There are currently 3 known Mars-crossing JFCs that may be big enough to make 60 km craters on Mars (the nearly extinct P/28 Neujmin 1, P/10 Tempel 2, and perhaps P/49 Arend-Rigaux). The rate is about once per 4 billion years. Thus we expect on the order of one 60 km martian impact crater in the past 3.5 Gyr made by a comet. There would be on the order of ten 30 km craters. Preliminary GCM simulations of comet impacts indicate that, while very large impact events generate global climate effects that can lead to precipitation in topographically favored locations anywhere on Mars, on the scale of 60 km craters the impact-generated rainfall becomes localized, such that, to first approximation, a uniquely wet impact might be expected to create uniquely heavy local precipitation on scales comparable to the impact crater.

Zahnle, K.; Colaprete, A.

2004-12-01

125

Unique biochemical and mineral composition of whale ear bones.  

PubMed

Abstract Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining characteristic of cetaceans is a thick and dense lip (pachyosteosclerotic involucrum) of an ear bone (the tympanic). This unique feature is absent in modern terrestrial artiodactyls and is suggested to be important in underwater hearing. Here, we investigate the mineralogical and biochemical properties of the involucrum, as these may hold clues to the aquatic adaptations of cetaceans. We compared bioapatites (enamel, dentine, cementum, and skeletal bone) of cetaceans with those of terrestrial artiodactyls and pachyosteosclerotic ribs of manatees (Sirenia). We investigated organic, carbonate, and mineral composition as well as crystal size and crystallinity index. In all studied variables, bioapatites of the cetacean involucrum were intermediate in composition and structure between those of tooth enamel on the one hand and those of dentine, cementum, and skeletal bone on the other. We also studied the amino acid composition of the cetacean involucrum relative to that of other skeletal bone. The central involucrum had low glycine and hydroxyproline concentrations but high concentrations of nonessential amino acids, unlike most bone samples but similar to the tympanic of hippos and the (pachyosteosclerotic) ribs of manatees. These amino acid results are evidence of rapid bone development. We hypothesize that the mineralogical and amino acid composition of cetacean bullae differs from that of other bone because of (1) functional modifications for underwater sound reception and (2) structural adaptations related to rapid ossification. PMID:24940922

Kim, Sora L; Thewissen, J G M; Churchill, Morgan M; Suydam, Robert S; Ketten, Darlene R; Clementz, Mark T

2014-01-01

126

Structural Modification of Resverastatin Phosphate.  

National Technical Information Service (NTIS)

Described herein are novel compounds having antineoplastic and antimicrobial activity, obtained via structural modifications of resveratrol and combretastatin A-4, methods for synthesis of these compounds, and their use in pharmaceutical composition and f...

G. R. Pettit M. P. Grealish

2003-01-01

127

Modifications to Replacement Costs System  

SciTech Connect

The purpose of this memorandum is to document the improvements and modifications made to the Replacement Costs of Crude Oil (REPCO) Supply Analysis System. While some of this work was performed under our previous support contract to DOE/ASFE, we are presenting all modifications and improvements are presented here for completeness. The memo primarily documents revisions made to the Lower-48 Onshore Model. Revisions and modifications made to other components and models in the REPCO system which are documented elsewhere are only highlighted in this memo. Generally, the modifications made to the Lower-48 Onshore Model reflect changes that have occurred in domestic drilling, oil field costs, and reserves since 1982, the date of the most recent available data used for the original Replacement Costs report, published in 1985.

Godec, M. [ICF Resources, Inc., Fairfax, VA (United States)

1989-05-18

128

Scheelite modification of neodymium arsenate  

SciTech Connect

The scheelite-like modification of neodymium arsenate produced without pressure was studied. The authors were unable to determine precisely the region of thermodynamic stability for the scheelite modification. The differential thermal analysis (DTA) curves on heating to 1000/degree/C and cooling revealed no thermal effects. An x-ray phase analysis of the sample after the DTA was performed and revealed the transition of the scheelite structure to the monazite. On this basis, it may be assumed that the scheelite modification is the low-temperature form. X-ray analysis, infrared spectroscopy, and Raman spectroscopy, and Raman spectroscopy were used to establish the existence of a polymorphic modification of NdAsO/sub 4/ of scheelite structure. The crystal lattice parameters were determined, and the spectral vibrational frequencies were identified.

Mazhenov, N.A.; Nurgaliev, B.Z.; Muldakhmetov, K.Z.

1988-12-01

129

Efficient and Comprehensive Representation of Uniqueness for Next-Generation Sequencing by Minimum Unique Length Analyses  

PubMed Central

As next generation sequencing technologies are getting more efficient and less expensive, RNA-Seq is becoming a widely used technique for transcriptome studies. Computational analysis of RNA-Seq data often starts with the mapping of millions of short reads back to the genome or transcriptome, a process in which some reads are found to map equally well to multiple genomic locations (multimapping reads). We have developed the Minimum Unique Length Tool (MULTo), a framework for efficient and comprehensive representation of mappability information, through identification of the shortest possible length required for each genomic coordinate to become unique in the genome and transcriptome. Using the minimum unique length information, we have compared different uniqueness compensation approaches for transcript expression level quantification and demonstrate that the best compensation is achieved by discarding multimapping reads and correctly adjusting gene model lengths. We have also explored uniqueness within specific regions of the mouse genome and enhancer mapping experiments. Finally, by making MULTo available to the community we hope to facilitate the use of uniqueness compensation in RNA-Seq analysis and to eliminate the need to make additional mappability files.

Storvall, Helena; Ramskold, Daniel; Sandberg, Rickard

2013-01-01

130

Chromatin Modifications in DNA Repair  

Microsoft Academic Search

A requirement of nuclear processes that use DNA as a substrate is the manipulation\\u000a of chromatin in which the DNA is packaged. Chromatin modifications cause alterations of histones\\u000a and DNA, and result in a permissive chromatin environment for these nuclear processes. Recent\\u000a advances in the fields of DNA repair and chromatin reveal that both histone modifications and chromatin-remodeling\\u000a complexes are essential for the

Ashby J. Morrison; Xuetong Shen

131

Unique features of animal mitochondrial translation systems  

PubMed Central

In animal mitochondria, several codons are non-universal and their meanings differ depending on the species. In addition, the tRNA structures that decipher codons are sometimes unusually truncated. These features seem to be related to the shortening of mitochondrial (mt) genomes, which occurred during the evolution of mitochondria. These organelles probably originated from the endosymbiosis of an aerobic eubacterium into an ancestral eukaryote. It is plausible that these events brought about the various characteristic features of animal mt translation systems, such as genetic code variations, unusually truncated tRNA and rRNA structures, unilateral tRNA recognition mechanisms by aminoacyl-tRNA synthetases, elongation factors and ribosomes, and compensation for RNA deficits by enlarged proteins. In this article, we discuss molecular mechanisms for these phenomena. Finally, we describe human mt diseases that are caused by modification defects in mt tRNAs.

Watanabe, Kimitsuna

2010-01-01

132

The Unique Nature of Mg2+ Channels  

NSDL National Science Digital Library

Considering the biological abundance and importance of Mg2+, there is a surprising lack of information regarding the proteins that transport Mg2+, the mechanisms by which they do so, and their physiological roles within the cell. The best characterized Mg2+ channel to date is the bacterial protein CorA, present in a wide range of bacterial species. The CorA homolog Mrs2 forms the mitochondrial Mg2+ channel in all eukaryotes. Physiologically, CorA is involved in bacterial pathogenesis, and the Mrs2 eukaryotic homolog is essential for cell survival. A second Mg2+ channel widespread in bacteria is MgtE. Its eukaryotic homologs are the SLC41 family of carriers. Physiological roles for MgtE and its homologs have not been established. Recently, the crystal structures for the bacterial CorA and MgtE Mg2+ channels were solved, the first structures of any divalent cation channel. As befits the unique biological chemistry of Mg2+, both structures are unique, unlike that of any other channel or transporter. Although structurally quite different, both CorA and MgtE appear to be gated in a similar manner through multiple Mg2+ binding sites in the cytosolic domain of the channels. These sites essentially serve as Mg2+ "sensors" of cytosolic Mg2+ concentration. Many questions about these channels remain, however, including the molecular basis of Mg2+ selectivity and the physiological role(s) of their eukaryotic homologs.

Andrea S Moomaw (Case Western Reserve University Pharmacology); Michael E Maguire (Case Western Reserve University Pharmacology)

2008-10-18

133

Unique transcriptome signature of mouse microglia.  

PubMed

Microglial cells can be derived directly from the dissociated brain tissue by sorting procedures, from postnatal glial cultures by mechanic isolation or from pluripotent stem cells by differentiation. The detailed molecular phenotype of microglia from different sources is still unclear. Here, we performed a whole transcriptome analysis of flow cytometry-sorted microglia, primary postnatal cultured microglia, embryonic stem cell derived microglia (ESdM), and other cell types. Microglia and ESdM, both cultured in serum-free medium, were closely related to sorted microglia and showed a unique transcriptome profile, clearly distinct to other myeloid cell types, T cells, astrocytes, and neurons. ESdM and primary cultured microglia showed strong overlap in their transcriptome. Only 143 genes were differentially expressed between both cell types, mainly derived from immune-related genes with a higher activation status of proinflammatory and immune defense genes in primary microglia compared to ESdM. Flow cytometry analysis of cell surface markers CD54, CD74, and CD274 selected from the microarray confirmed the close phenotypic relation between ESdM and primary cultured microglia. Thus, assessment of genome-wide transcriptional regulation demonstrates that microglial cells are unique and clearly distinct from other macrophage cell types. PMID:23832717

Beutner, Clara; Linnartz-Gerlach, Bettina; Schmidt, Susanne V; Beyer, Marc; Mallmann, Michael R; Staratschek-Jox, Andrea; Schultze, Joachim L; Neumann, Harald

2013-09-01

134

Mast cells: A unique source of renin  

PubMed Central

In addition to the traditional renin–angiotensin system, a great deal of evidence favors the existence of numerous independent tissue-specific renin–angiotensin systems. We report that mast cells are an additional source of renin and constitute a unique extrarenal renin–angiotensin system. We use renin-specific antibodies to demonstrate that cardiac mast cells contain renin. Extending this observation to the human mast cell line HMC-1, we show that these mast cells also express renin. The HMC-1 renin RT-PCR product is 100% homologous to Homo sapiens renin. HMC-1 cells also contain renin protein, as demonstrated both by immunoblot and immunocytochemical analyses. Renin released from HMC-1 cells is active; furthermore, HMC-1 cells are able to synthesize renin. It is known that, in the heart, mast cells are found in the interstitium in close proximity to nerves and myocytes, which both express angiotensin II receptors. Inasmuch as myocardial interstitium contains angiotensinogen and angiotensin-converting enzyme, and because we were able to detect renin only in mast cells, we postulate that the release of renin from cardiac mast cells is the pivotal event triggering local formation of angiotensin II. Because of the ubiquity of mast cells, our results represent a unique paradigm for understanding local renin–angiotensin systems, not just in the heart, but in all tissues. Our findings provide a rationale for targeting mast cells in conjunction with renin–angiotensin system inhibitors in the management of angiotensin II-related dysfunctions.

Silver, Randi B.; Reid, Alicia C.; Mackins, Christina J.; Askwith, Trevor; Schaefer, Ulrich; Herzlinger, Doris; Levi, Roberto

2004-01-01

135

Beryllium - A Unique Material in Nuclear Applications  

SciTech Connect

Beryllium, due to its unique combination of structural, chemical, atomic number, and neutron absorption cross section characteristics, has been used successfully as a neutron reflector for three generations of nuclear test reactors at the Idaho National Engineering and Environmental Laboratory (INEEL). The Advanced Test Reactor (ATR), the largest test reactor in the world, has utilized five successive beryllium neutron reflectors and is scheduled for continued operation with a sixth beryllium reflector. A high radiation environment in a test reactor produces radiation damage and other changes in beryllium. These changes necessitate safety analysis of the beryllium, methods to predict performance, and appropriate surveillances. Other nuclear applications also utilize beryllium. Beryllium, given its unique atomic, physical, and chemical characteristics, is widely used as a “window” for x-rays and gamma rays. Beryllium, intimately mixed with high-energy alpha radiation emitters has been successfully used to produce neutron sources. This paper addresses operational experience and methodologies associated with the use of beryllium in nuclear test reactors and in “windows” for x-rays and gamma rays. Other nuclear applications utilizing beryllium are also discussed.

T., A. Tomberlin

2004-11-01

136

Unmanned Aerial Vehicles unique cost estimating requirements  

NASA Astrophysics Data System (ADS)

Unmanned Aerial Vehicles (UAVs), also referred to as drones, are aerial platforms that fly without a human pilot onboard. UAVs are controlled autonomously by a computer in the vehicle or under the remote control of a pilot stationed at a fixed ground location. There are a wide variety of drone shapes, sizes, configurations, complexities, and characteristics. Use of these devices by the Department of Defense (DoD), NASA, civil and commercial organizations continues to grow. UAVs are commonly used for intelligence, surveillance, reconnaissance (ISR). They are also use for combat operations, and civil applications, such as firefighting, non-military security work, surveillance of infrastructure (e.g. pipelines, power lines and country borders). UAVs are often preferred for missions that require sustained persistence (over 4 hours in duration), or are “ too dangerous, dull or dirty” for manned aircraft. Moreover, they can offer significant acquisition and operations cost savings over traditional manned aircraft. Because of these unique characteristics and missions, UAV estimates require some unique estimating methods. This paper describes a framework for estimating UAV systems total ownership cost including hardware components, software design, and operations. The challenge of collecting data, testing the sensitivities of cost drivers, and creating cost estimating relationships (CERs) for each key work breakdown structure (WBS) element is discussed. The autonomous operation of UAVs is especially challenging from a software perspective.

Malone, P.; Apgar, H.; Stukes, S.; Sterk, S.

137

The Unique Nature of Mg2+ Channels  

PubMed Central

Considering the biological abundance and importance of Mg2+, there is a surprising lack of information regarding the proteins that transport Mg2+, the mechanisms by which they do so, and their physiological roles within the cell. The best characterized Mg2+ channel to date is the bacterial protein CorA, present in a wide range of bacterial species. The CorA homolog Mrs2 forms the mitochondrial Mg2+ channel in all eukaryotes. Physiologically, CorA is involved in bacterial pathogenesis, and the Mrs2 eukaryotic homolog is essential for cell survival. A second Mg2+ channel widespread in bacteria is MgtE. Its eukaryotic homologs are the SLC41 family of carriers. Physiological roles for MgtE and its homologs have not been established. Recently, the crystal structures for the bacterial CorA and MgtE Mg2+ channels were solved, the first structures of any divalent cation channel. As befits the unique biological chemistry of Mg2+, both structures are unique, unlike that of any other channel or transporter. Although structurally quite different, both CorA and MgtE appear to be gated in a similar manner through multiple Mg2+ binding sites in the cytosolic domain of the channels. These sites essentially serve as Mg2+ “sensors” of cytosolic Mg2+ concentration. Many questions about these channels remain, however, including the molecular basis of Mg2+ selectivity and the physiological role(s) of their eukaryotic homologs.

Moomaw, Andrea S.; Maguire, Michael E.

2009-01-01

138

Unique Molecular Characteristics of Pediatric Myxopapillary Ependymoma  

PubMed Central

Myxopapillary ependymoma (MEPN) generally can be cured by gross total surgical resection and usually manifest a favorable prognosis. However, surgery is less curative in tumors that are large, multifocal or extend outside the thecal sac. Late recurrences may occur, particularly in pediatric patients. The role of adjuvant therapy is unclear in the clinical management of recurrent tumors. Clinical trial design requires a better understanding of tumor biology. Unique molecular features of MEPN were investigated by using microarray technology to compare the gene expression of five pediatric MEPN to 24 pediatric intracranial ependymoma (EPN). The upregulation of three genes of interest, homeobox B13 (HOXB13), neurofilament, light polypeptide (NEFL) and PDGFR?, was further studied by immunohistochemistry in a larger cohort that included adult MEPN and EPN specimens. Protein expression in MEPN was compared to subependymoma, spinal EPN, intracranial EPN and normal fetal and adult ependyma. Immunoreactivity for HOXB13, NEFL and PDGFR? was strongest in MEPN and virtually absent in subependymoma. Spinal and intracranial EPN generally expressed weak or focal staining. MEPN manifests unique gene and protein expression patterns compared to other EPNs. Aberrant expression of HOXB13 suggests possible recapitulation of developmental pathways in MEPN tumorigenesis. PDGFR? may be a potential therapeutic target in recurrent MEPN.

Barton, Valerie N; Donson, Andrew M; Kleinschmidt-DeMasters, Bette K; Birks, Diane K; Handler, Michael H; Foreman, Nicholas K

2010-01-01

139

Astronomy Outreach for Large and Unique Audiences  

NASA Astrophysics Data System (ADS)

In this session, we discuss different approaches to reaching large audiences. In addition to star parties and astronomy events, the audiences for some of the events include music concerts or festivals, sick children and their families, minority communities, American Indian reservations, and tourist sites such as the National Mall. The goal is to bring science directly to the public—to people who attend astronomy events and to people who do not come to star parties, science museums, or science festivals. These programs allow the entire community to participate in astronomy activities to enhance the public appreciation of science. These programs attract large enthusiastic crowds often with young children participating in these family learning experiences. The public will become more informed, educated, and inspired about astronomy and will also be provided with information that will allow them to continue to learn after this outreach activity. Large and unique audiences often have common problems, and their solutions and the lessons learned will be presented. Interaction with the participants in this session will provide important community feedback used to improve astronomy outreach for large and unique audiences. New ways to expand astronomy outreach to new large audiences will be discussed.

Lubowich, D.; Sparks, R. T.; Pompea, S. M.; Kendall, J. S.; Dugan, C.

2013-04-01

140

Tescaco Canada completes unique horizontal drilling program  

SciTech Connect

Describes how shallow 260- to 660-ft (80- to 200-m) oil sands were developed by drilling highly deviated wells using a drilling rig with a 45 degree-slanted mast. Combination of shallow depth and unconsolidated bituminous sands presented unique drilling problems to obtain long horizontal sections. Presents graphs showing breakdown of well depth vs. days, the well bore program, and a well completion schematic. Designed for both vertical and slant-hole drilling, the hydraulic rig increased drilling and completion time and costs. Concludes that the information, techniques, equipment design, and expertise gained from drilling the 3 horizontal wells are invaluable in the quest toward commercial production of bitumen by in-situ methods. Suggests that by drilling to 2,082 ft DD (635 m) with 1,246 ft (390 m) of hole horizontal in the oil sands, a significant advance in very shallow formation drilling has been achieved.

Loscam, D.C.

1982-09-01

141

Practice effects: a unique cognitive variable.  

PubMed

Practice effects are improvements in cognitive test performance due to repeated evaluation with the same or similar test materials. Prior studies have reported that these improvements can vary with age, education/intellect, and disease status. However, additional information is needed about variables that influence practice effects. The current study prospectively quantified short-term practice effects in 268 community-dwelling older adults and compared these practice effects to demographic variables, global cognition, premorbid intellect, depression, and individual cognitive domains. Overall, practice effects were not significantly related to most demographic and clinical characteristics or individual cognitive domains, which was contrary to our hypotheses. However, since practice effects appear to be uninfluenced by many variables that typically affect cognitive scores, they may be a unique and valuable tool that could be applied in a number of diverse patient groups. PMID:23020261

Duff, Kevin; Callister, Catherine; Dennett, Kathryn; Tometich, Danielle

2012-01-01

142

Texaco Canada completes unique horizontal drilling program  

SciTech Connect

Texaco Canada Resources Ltd. recently completed an innovative drilling program to tap shallow reserves in its Athabasca oil sands lease, south and east of Fort McMurray, Alberta. Texaco successfully drilled 3 wells using a drilling rig with a 45 degrees-slanted mast. Since 1972, Texaco has operated an in situ pilot project in their Athabasca field. In 1979, the company recognized the need to reduce capital cost for a commercial venture while providing improved recovery in development of the oil sands. Texaco could only develop these shallow 260- to 660-ft (80- to 200-m) oil sands by drilling highly deviated wells. Furthermore, the combination of shallow depth and unconsolidated bituminous sands presented unique drilling problems to obtain long horizontal sections. Although the path followed in drilling was not always as proposed, the company achieved its objectives.

Loxam, D.C.

1982-09-01

143

Epigenetic Modifications and Diabetic Retinopathy  

PubMed Central

Diabetic retinopathy remains one of the most debilitating chronic complications, but despite extensive research in the field, the exact mechanism(s) responsible for how retina is damaged in diabetes remains ambiguous. Many metabolic pathways have been implicated in its development, and genes associated with these pathways are altered. Diabetic environment also facilitates epigenetics modifications, which can alter the gene expression without permanent changes in DNA sequence. The role of epigenetics in diabetic retinopathy is now an emerging area, and recent work has shown that genes encoding mitochondrial superoxide dismutase (Sod2) and matrix metalloproteinase-9 (MMP-9) are epigenetically modified, activates of epigenetic modification enzymes, histone lysine demethylase 1 (LSD1), and DNA methyltransferase are increased, and the micro RNAs responsible for regulating nuclear transcriptional factor and VEGF are upregulated. With the growing evidence of epigenetic modifications in diabetic retinopathy, better understanding of these modifications has potential to identify novel targets to inhibit this devastating disease. Fortunately, the inhibitors and mimics targeted towards histone modification, DNA methylation, and miRNAs are now being tried for cancer and other chronic diseases, and better understanding of the role of epigenetics in diabetic retinopathy will open the door for their possible use in combating this blinding disease.

Kowluru, Renu A.; Santos, Julia M.; Mishra, Manish

2013-01-01

144

Epigenetic modifications and diabetic retinopathy.  

PubMed

Diabetic retinopathy remains one of the most debilitating chronic complications, but despite extensive research in the field, the exact mechanism(s) responsible for how retina is damaged in diabetes remains ambiguous. Many metabolic pathways have been implicated in its development, and genes associated with these pathways are altered. Diabetic environment also facilitates epigenetics modifications, which can alter the gene expression without permanent changes in DNA sequence. The role of epigenetics in diabetic retinopathy is now an emerging area, and recent work has shown that genes encoding mitochondrial superoxide dismutase (Sod2) and matrix metalloproteinase-9 (MMP-9) are epigenetically modified, activates of epigenetic modification enzymes, histone lysine demethylase 1 (LSD1), and DNA methyltransferase are increased, and the micro RNAs responsible for regulating nuclear transcriptional factor and VEGF are upregulated. With the growing evidence of epigenetic modifications in diabetic retinopathy, better understanding of these modifications has potential to identify novel targets to inhibit this devastating disease. Fortunately, the inhibitors and mimics targeted towards histone modification, DNA methylation, and miRNAs are now being tried for cancer and other chronic diseases, and better understanding of the role of epigenetics in diabetic retinopathy will open the door for their possible use in combating this blinding disease. PMID:24286082

Kowluru, Renu A; Santos, Julia M; Mishra, Manish

2013-01-01

145

Polymer surface modification by plasmas and photons  

NASA Astrophysics Data System (ADS)

Polymers have been applied successfully in fields such as adhesion, biomaterials, protective coatings, friction and wear, composites, microelectronic devices, and thin-film technology. In general, special surface properties with regard to chemical composition, hydrophilicity, roughness, crystallinity, conductivity, lubricity, and cross-linking density are required for the success of these applications. Polymers very often do not possess the surface properties needed for these applications. However, they have excellent bulk physical and chemical properties, are inexpensive, and are easy to process. For these reasons, surface modification techniques which can transform these inexpensive materials into highly valuable finished products have become an important part of the plastics and many other industries. In recent years, many advances have been made in developing surface treatments to alter the chemical and physical properties of polymer surfaces without affecting bulk properties. Common surface modification techniques include treatments by flame, corona, plasmas, photons, electron beams, ion beams, X-rays, and ?-rays. Plasma treatment is probably the most versatile surface treatment technique. Different types of gases such as argon, oxygen, nitrogen, fluorine, carbon dioxide, and water can produce the unique surface properties required by various applications. For example, oxygen-plasma treatment can increase the surface energy of polymers, whereas fluorine-plasma treatment can decrease the surface energy and improve the chemical inertness. Cross-linking at a polymer surface can be introduced by an inert-gas plasma. Modification by plasma treatment is usually confined to the top several hundred ångströms and does not affect the bulk properties. The main disadvantage of this technique is that it requires a vacuum system, which increases the cost of operation. Thin polymer films with unique chemical and physical properties are produced by plasma polymerization. This technology is still in its infancy, and the plasma chemical process is not fully understood. The films are prepared by vapor phase deposition and can be formed on practically any substrate with good adhesion between the film and the substrate. These films, which are usually highly cross-linked and pinhole-free, have very good barrier properties. Such films find great potential in biomaterial applications and in the microelectronics industry. Very high-power microwave-driven mercury lamps are available, and they are used in UV-hardening of photoresist patterns for image stabilization at high temperatures. Other applications of UV irradiation include surface photo-oxidation, increase of hydrophilicity, and photocuring of paintings. Pulsed UV-lasers are used in surface modification in many areas. Pulsed UV-laser irradiation can produce submicron periodic linear and dot patterns on polymer surfaces without photomask. These interference patterns can be used to increase surface roughness of inert polymers for improved adhesion. These images can also be transferred to silicon surfaces by reactive ion etching. Pulsed laser beams can be applied to inert polymer surfaces for increased hydrophilicity and wettability. Polymer surfaces treated by pulsed UV-laser irradiation can be positively or negatively charged to enhance chemical reactivity and processability. Pulsed UV-laser exposures with high fluence give rise to photoablation with a clean wall profile. There are many other practical applications of laser photoablation, including via-hole fabrication, and diamond-film deposition. The present review discusses all these current applications, especially in the biomedical and microelectronics areas.

Chan, C.-M.; Ko, T.-M.; Hiraoka, H.

1996-05-01

146

The unique inner landscape of the Anthropocene  

NASA Astrophysics Data System (ADS)

A characteristic aspect of the Anthropocene is the suite of novel changes made to the surface and subsurface of the Earth by human action, both on land and, increasingly, on and below the sea floor. Geologically, these geomorphological phenomena include features that relate to both lithostratigraphic and biostratigraphic classification, the latter resulting from considering human constructions and modifications as a form of trace fossil system, albeit one that is of unprecedentedly large scale. As regards the potential formalizing of the Anthropocene, one question to be pursued relates to the chronostratigraphic definition of the phenomena involved: that is, given that many of these transformations are diachronous on human timescales, can an Anthropocene Series, with a synchronous time boundary, be characterized and mapped across the Earth's surface? Efforts to answer this question should help in the understanding of the Anthropocene within its geological context, and also in exploring the stratigraphic relation between time and rock generally at very fine stratigraphic timescales. Zalasiewicz, J., Williams M, Fortey, R.A., Smith, A.G., Barry, T.L. Coe, A.L., Bown, P.R., Gale, A., Gibbard, P.L., Gregory, F.J., Hounslow, M.W., Kerr, A.C., Pearson, P., Knox, R., Powell, J., Waters, C., Marshall, J., Oates, M., Rawson, P. & Stone, P. 2011. Stratigraphy of the Anthropocene. Philosophical Transactions of the Royal Society A369, 1036-1055.

Zalasiewicz, Jan

2013-04-01

147

Surface modification for corrosion resistance  

SciTech Connect

The raw gas environments that arise from coal gasification have chemical compositions that are low in pO{sub 2} and moderate-to-high in pS{sub 2}. Metallic materials for service in such an environment undergo predominantly sulfidation attack at temperatures of 400 to 700{degree}C. Modification of alloy compositions in bulk can alter the scaling processes and lead to improvements in corrosion resistance, but the benefits can only be attained at temperatures much higher than the service temperatures of the components. Modification of surfaces of structural components by several of the coating techniques examined in this study showed substantial benefit in corrosion resistance when tested in simulated coal gasification environments. The paper presents several examples of surface modification and their corrosion performance.

Natesan, K.

1993-06-01

148

Weather Modification A Theoretician's Viewpoint.  

NASA Astrophysics Data System (ADS)

Early progress in weather modification is attributed to a healthy interaction between theory and experiment. During the 1970s, a divergence of approaches took place. A "theoretical/experimental" approach, exemplified by the Cascade Project, focused on testing scientific hypotheses; an "observational/experimental" approach, exemplified by the Colorado River Basin Pilot Project, sought to enhance understanding of the seeding process through more detailed observations.The theoretical/experimental school soon came to focus almost exclusively on natural cloud processes, leaving the field of weather modification nearly devoid of a theoretical component. It is suggested that this theoretical component is necessary to revitalize the field of weather modification.Key questions are addressed. These include 1) identification of clouds that are amenable to seeding; 2) glaciogenic versus hygroscopic seeding; 3) optimizing critical seeding variables, such as seed particle concentration for glaciogenic seeding and seed particle size for hygroscopic seeding; and 4) seeding for hail suppression.

Young, Kenneth C.

1996-11-01

149

Altered Histone Modifications in Gliomas  

PubMed Central

Gliomas are the most frequently occurring primary brain tumors in adults. Although they exist in different malignant stages, including histologically benign forms and highly aggressive states, most gliomas are clinically challenging for neuro-oncologists because of their infiltrative growth patterns and inherent relapse tendency with increased malignancy. Once this disease reaches the glioblastoma multiforme stage, the prognosis of patients is dismal: median survival time is 15 months. Extensive genetic analyses of glial tumors have revealed a variety of deregulated genetic pathways involved in DNA repair, apoptosis, cell migration/adhesion, and cell cycle. Recently, it has become evident that epigenetic alterations may also be an important factor for glioma genesis. Of epigenetic marks, histone modification is a key mark that regulates gene expression and thus modulates a wide range of cellular processes. In this review, I discuss the neuro-oncological significance of altered histone modifications and modifiers in glioma patients while briefly overviewing the biological roles of histone modifications.

2014-01-01

150

Playing TETris with DNA modifications.  

PubMed

Methylation of the fifth carbon of cytosine was the first epigenetic modification to be discovered in DNA. Recently, three new DNA modifications have come to light: hydroxymethylcytosine, formylcytosine, and carboxylcytosine, all generated by oxidation of methylcytosine by Ten Eleven Translocation (TET) enzymes. These modifications can initiate full DNA demethylation, but they are also likely to participate, like methylcytosine, in epigenetic signalling per se. A scenario is emerging in which coordinated regulation at multiple levels governs the participation of TETs in a wide range of physiological functions, sometimes via a mechanism unrelated to their enzymatic activity. Although still under construction, a sophisticated picture is rapidly forming where, according to the function to be performed, TETs ensure epigenetic marking to create specific landscapes, and whose improper build-up can lead to diseases such as cancer and neurodegenerative disorders. PMID:24825349

Delatte, Benjamin; Deplus, Rachel; Fuks, François

2014-06-01

151

Existence and uniqueness of Gibbs states for a statistical mechanical polyacetylene model  

NASA Astrophysics Data System (ADS)

One-dimensional polyacetylene is studied as a model of statistical mechanics. In a semiclassical approximation the system is equivalent to a quantum XY model interacting with unbounded classical spins in one-dimensional lattice space Z. By establishing uniform estimates, an infinite-volume-limit Hilbert space, a strongly continuous time evolution group of unitary operators, and an invariant vector are constructed. Moreover, it is proven that any infinite-limit state satisfies Gibbs conditions. Finally, a modification of Araki's relative entropy method is used to establish the uniqueness of Gibbs states.

Park, Yong Moon

1987-02-01

152

Manufacturer evaluations of endograft modifications.  

PubMed

The motivation to modify the design of a vascular device can arise from a number of sources. Clinical experience with the unmodified device could suggest new design modifications to improve device performance or clinical outcomes. Similarly, clinical success with a device often suggests modifications that could broaden the applicability of the device to enable treatment of different or more advanced disease states. As a specific example, both of these scenarios have arisen during the last decade in the evolution of endovascular grafts for the treatment of abdominal aortic aneurysms, with modifications enabling the treatment of patients with shorter infrarenal necks, more angulated anatomy, and smaller access vessels. These modifications have been made by manufacturers and additionally by physicians who create branched and fenestrated devices. The experience to date with the use of fenestrated devices and the development of chimney, snorkel, and periscope techniques suggests that modifications to off-the-shelf devices may provide some clinical benefit. This experience provides additional motivation for manufacturers to develop devices to address the clinical needs not met with their current product lines. For manufacturers, the device development process includes an assessment of the new device design to determine the appropriate evaluation strategy to support the safety and effectiveness of the modified device. This report provides a high-level overview of the process generally followed by device manufacturers to evaluate a proposed device modification before market release, in accordance with local country regulations and recognized international standards such as the International Organization of Standardization (ISO) standards for endovascular grafts (ISO 25539 Part 1). PMID:23446123

Waninger, Matthew S; Whirley, Robert G; Smith, Louis J; Wolf, Ben S

2013-03-01

153

[Targeted genome modifications using TALEN].  

PubMed

Precise modifications of genomes have been one of the biggest goals in the fields of biotechnology and biomedical research. Recent discovery of TALE (transcription activator-like effectors) and the engineering of customized TALEN (transcription activator-like effector nucleases) allowed rapid genome editing in a variety of cell types and different model organisms. TALEN are molecular scissors used to induce a wide range of specific and efficient genomic modifications. TALEN promise to have profound impacts on biological and medical research over the coming years. PMID:24572118

Dupret, Barbara; Angrand, Pierre-Olivier

2014-02-01

154

Improvement of stability conditions, accuracy and uniqueness of penalty approach in contact modeling  

NASA Astrophysics Data System (ADS)

The main objective of this paper is to improve stability conditions, uniqueness and convergence of numerical analysis of metal forming processes with contact constraints enforced by the penalty method. A commonly known drawback of this approach is the choice of penalty factor values. When assumed too low, they result in inaccurate fulfillment of the constraints while when assumed too high, they lead to ill-conditioning of the equations system which affects stability and uniqueness of the solution. The proposed modification of the penalty algorithm consists in adaptive estimation of the penalty factor values for the particular system of finite element equations and for the assumed allowed inaccuracy in fulfillment of the contact constraints. The algorithm is tested on realistic examples of sheet metal forming. The finite element code based on flow approach formulation (for rigid-plastic and rigid-viscoplastic material model) has been used.

Bednarek, Tomasz; Kowalczyk, Piotr

2013-06-01

155

Structural characteristics, dispersion, and modification of fibrous brucite  

NASA Astrophysics Data System (ADS)

Fibrous brucite has very unique structure and physical properties. Brucite fibers were exfoliated into single nanofibers by using dioctyl sodium sulfosuccinate (AOT) as a dispersant through mechanical agitation and ultrasonic dispersion; and then, the nanofibers were modified by stearic acid and (3-aminopropyl)triethoxysilane (?-APS) compound modification agent. The nanofibers were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis. It is found that AOT has good effect on the dispersion. The single fiber has a consistent morphology, and fibrous brucite is dispersed and modified without destroying the crystal structure. Infrared and thermal analysis shows that the surface modification of fibrous brucite is achieved by forming chemical bonds between the coupling agent and magnesium hydroxide.

Cao, Xi; Chuan, Xiu-yun

2014-01-01

156

The placenta harbors a unique microbiome.  

PubMed

Humans and their microbiomes have coevolved as a physiologic community composed of distinct body site niches with metabolic and antigenic diversity. The placental microbiome has not been robustly interrogated, despite recent demonstrations of intracellular bacteria with diverse metabolic and immune regulatory functions. A population-based cohort of placental specimens collected under sterile conditions from 320 subjects with extensive clinical data was established for comparative 16S ribosomal DNA-based and whole-genome shotgun (WGS) metagenomic studies. Identified taxa and their gene carriage patterns were compared to other human body site niches, including the oral, skin, airway (nasal), vaginal, and gut microbiomes from nonpregnant controls. We characterized a unique placental microbiome niche, composed of nonpathogenic commensal microbiota from the Firmicutes, Tenericutes, Proteobacteria, Bacteroidetes, and Fusobacteria phyla. In aggregate, the placental microbiome profiles were most akin (Bray-Curtis dissimilarity <0.3) to the human oral microbiome. 16S-based operational taxonomic unit analyses revealed associations of the placental microbiome with a remote history of antenatal infection (permutational multivariate analysis of variance, P = 0.006), such as urinary tract infection in the first trimester, as well as with preterm birth <37 weeks (P = 0.001). PMID:24848255

Aagaard, Kjersti; Ma, Jun; Antony, Kathleen M; Ganu, Radhika; Petrosino, Joseph; Versalovic, James

2014-05-21

157

Unique Ganglioside Recognition Strategies for Clostridial Neurotoxins  

SciTech Connect

Botulinum neurotoxins (BoNTs) and tetanus neurotoxin are the causative agents of the paralytic diseases botulism and tetanus, respectively. The potency of the clostridial neurotoxins (CNTs) relies primarily on their highly specific binding to nerve terminals and cleavage of SNARE proteins. Although individual CNTs utilize distinct proteins for entry, they share common ganglioside co-receptors. Here, we report the crystal structure of the BoNT/F receptor-binding domain in complex with the sugar moiety of ganglioside GD1a. GD1a binds in a shallow groove formed by the conserved peptide motif E ... H ... SXWY ... G, with additional stabilizing interactions provided by two arginine residues. Comparative analysis of BoNT/F with other CNTs revealed several differences in the interactions of each toxin with ganglioside. Notably, exchange of BoNT/F His-1241 with the corresponding lysine residue of BoNT/E resulted in increased affinity for GD1a and conferred the ability to bind ganglioside GM1a. Conversely, BoNT/E was not able to bind GM1a, demonstrating a discrete mechanism of ganglioside recognition. These findings provide a structural basis for ganglioside binding among the CNTs and show that individual toxins utilize unique ganglioside recognition strategies.

Benson, Marc A.; Fu, Zhuji; Kim, Jung-Ja P.; Baldwin, Michael R. (MCW); (UMC)

2012-03-15

158

Unique features in the ARIES glovebox line  

SciTech Connect

A series of unique features have been incorporated into the Advanced Recovery and Integrated Extraction System (ARIES) at the Los Alamos National Laboratory, TA-55 Plutonium Facility. The features enhance the material handling in the process of the dismantlement of nuclear weapon primaries in the glovebox line. Incorporated into these features are the various plutonium process module`s different ventilation zone requirements that the material handling systems must meet. These features include a conveyor system that consists of a remotely controlled cart that transverses the length of the conveyor glovebox, can be operated from a remote location and can deliver process components to the entrance of any selected module glovebox. Within the modules there exists linear motion material handling systems with lifting hoist, which are controlled via an Allen Bradley control panel or local control panels. To remove the packaged products from the hot process line, the package is processed through an air lock/electrolytic decontamination process that removes the radioactive contamination from the outside of the package container and allows the package to be removed from the process line.

Martinez, H.E.; Brown, W.G.; Flamm, B.; James, C.A.; Laskie, R.; Nelson, T.O.; Wedman, D.E.

1998-12-31

159

Is loop quantization in cosmology unique?  

SciTech Connect

We reexamine the process of loop quantization for flat isotropic models in cosmology. In particular, we contrast different inequivalent 'loop quantizations' of these simple models through their respective successes and limitations and assess whether they can lead to any viable physical description. We propose three simple requirements which any such admissible quantum model should satisfy: (i) independence from any auxiliary structure, such as a fiducial interval/cell introduced to define the phase space when integrating over noncompact manifolds; (ii) existence of a well defined classical limit, and (iii) a sensible 'Planck scale' where quantum gravitational effects become manifest. We show that even when it may seem that one can have several possible loop quantizations, these physical requirements considerably narrow down the consistent choices. Apart from the so-called improved dynamics of loop quantum cosmology, none of the other available inequivalent loop quantizations pass the above tests, showing the limitations of lattice refinement models to approximate the homogeneous sector and loop modified quantum geometrodynamics. We conclude that amongst a large class of loop quantizations in isotropic cosmology, there is a unique consistent choice.

Corichi, Alejandro [Instituto de Matematicas, Unidad Morelia, Universidad Nacional Autonoma de Mexico, UNAM-Campus Morelia, Apartado Postal 61-3, Morelia, Michoacan 58090 (Mexico); Center for Fundamental Theory, Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Singh, Parampreet [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada)

2008-07-15

160

Unique animal prenyltransferase with monoterpene synthase activity  

NASA Astrophysics Data System (ADS)

Monoterpenes are structurally diverse natural compounds that play an essential role in the chemical ecology of a wide array of organisms. A key enzyme in monoterpene biosynthesis is geranyl diphosphate synthase (GPPS). GPPS is an isoprenyl diphosphate synthase that catalyzes a single electrophilic condensation reaction between dimethylallyl diphosphate (C5) and isopentenyl diphosphate (C5) to produce geranyl diphosphate (GDP; C10). GDP is the universal precursor to all monoterpenes. Subsequently, monoterpene synthases are responsible for the transformation of GDP to a variety of acyclic, monocyclic, and bicyclic monoterpene products. In pheromone-producing male Ips pini bark beetles (Coleoptera: Scolytidae), the acyclic monoterpene myrcene is required for the production of the major aggregation pheromone component, ipsdienol. Here, we report monoterpene synthase activity associated with GPPS of I. pini. Enzyme assays were performed on recombinant GPPS to determine the presence of monoterpene synthase activity, and the reaction products were analyzed by coupled gas chromatography-mass spectrometry. The functionally expressed recombinant enzyme produced both GDP and myrcene, making GPPS of I. pini a bifunctional enzyme. This unique insect isoprenyl diphosphate synthase possesses the functional plasticity that is characteristic of terpene biosynthetic enzymes of plants, contributing toward the current understanding of product specificity of the isoprenoid pathway.

Gilg, Anna B.; Tittiger, Claus; Blomquist, Gary J.

2009-06-01

161

Unique animal prenyltransferase with monoterpene synthase activity.  

PubMed

Monoterpenes are structurally diverse natural compounds that play an essential role in the chemical ecology of a wide array of organisms. A key enzyme in monoterpene biosynthesis is geranyl diphosphate synthase (GPPS). GPPS is an isoprenyl diphosphate synthase that catalyzes a single electrophilic condensation reaction between dimethylallyl diphosphate (C(5)) and isopentenyl diphosphate (C(5)) to produce geranyl diphosphate (GDP; C(10)). GDP is the universal precursor to all monoterpenes. Subsequently, monoterpene synthases are responsible for the transformation of GDP to a variety of acyclic, monocyclic, and bicyclic monoterpene products. In pheromone-producing male Ips pini bark beetles (Coleoptera: Scolytidae), the acyclic monoterpene myrcene is required for the production of the major aggregation pheromone component, ipsdienol. Here, we report monoterpene synthase activity associated with GPPS of I. pini. Enzyme assays were performed on recombinant GPPS to determine the presence of monoterpene synthase activity, and the reaction products were analyzed by coupled gas chromatography-mass spectrometry. The functionally expressed recombinant enzyme produced both GDP and myrcene, making GPPS of I. pini a bifunctional enzyme. This unique insect isoprenyl diphosphate synthase possesses the functional plasticity that is characteristic of terpene biosynthetic enzymes of plants, contributing toward the current understanding of product specificity of the isoprenoid pathway. PMID:19277597

Gilg, Anna B; Tittiger, Claus; Blomquist, Gary J

2009-06-01

162

Alkyne cycloaddition to a titanocene oxide as a route to cyclopentadienyl modification.  

PubMed

Addition of terminal or internal alkynes to a base-free titanocene oxide results in synthesis of the corresponding oxometallocyclobutene. With appropriate cyclopentadienyl substitution, these compounds undergo reversible C?C reductive elimination offering a unique approach to cyclopentadienyl modification. PMID:24796547

Pappas, Iraklis; Chirik, Paul J

2014-06-10

163

Microfabrication, surface modification, and laser guidance techniques to create a neuron biochip  

Microsoft Academic Search

In this report we illustrate our application of soft lithography-based microfabrication, surface modification, and our unique laser cell-patterning system toward the creation of neuron biochips. We deposited individual forebrain neurons from Day 7 embryonic chicks into two rows of eight in a silicon microstructure aligned over a microelectrode array (MEA). The polydimethylsiloxane (PDMS) membrane with microstructures to confine cells and

Russell Kirk Pirlo; Xiang Peng; Xiaocong Yuan; Bruce Zhi Gao

2008-01-01

164

Scalable human ES culture for therapeutic use: propagation, differentiation, genetic modification and regulatory issues  

Microsoft Academic Search

Embryonic stem cells unlike most adult stem cell populations can replicate indefinitely while preserving genetic, epigenetic, mitochondrial and functional profiles. ESCs are therefore an excellent candidate cell type for providing a bank of cells for allogenic therapy and for introducing targeted genetic modifications for therapeutic intervention. This ability of prolonged self-renewal of stem cells and the unique advantages that this

M Rao

2008-01-01

165

Chemical modification of semiconductor surfaces  

NASA Technical Reports Server (NTRS)

Results of research on the chemical modification of TiO2 powders in the gas phase and the examination of the modified powders by infrared absorption spectroscopy are comprehensively summarized. The range of information obtainable by IR spectroscopy of chemically modified semiconductors, and a definition of the optimum reaction conditions for synthesizing a monolayer of methylsilanes using vapor phase reaction conditions were considered.

Finklea, H. O.

1981-01-01

166

Epigenetic modifications and human disease  

Microsoft Academic Search

Epigenetics is one of the most rapidly expanding fields in biology. The recent characterization of a human DNA methylome at single nucleotide resolution, the discovery of the CpG island shores, the finding of new histone variants and modifications, and the unveiling of genome-wide nucleosome positioning maps highlight the accelerating speed of discovery over the past two years. Increasing interest in

Anna Portela; Manel Esteller

2010-01-01

167

Selective Modification of Glutathione Metabolism  

Microsoft Academic Search

Glutathione, a tripeptide thiol found in virtually all cells, functions in metabolism, transport, and cellular protection. It participates in the reduction of disulfides and other molecules, and conjugates with compounds of exogenous and endogenous origin. It protects cells against the destructive effects of reactive oxygen intermediates and free radicals. Modifications of glutathione metabolism may be achieved by administration of selective

Alton Meister

1983-01-01

168

Modification of 4330 alloy steel.  

National Technical Information Service (NTIS)

We have developed a modification of 4330 alloy steel which does not have an exact equivalent expressed in any standard specification. When we compare the ballistic performance of our modified cast steel in thicknesses of about 120 mm with that of stacked,...

R. Gogolewski B. J. Cunningham R. Gentile S. Fleming

1990-01-01

169

Demonstrating Allotropic Modifications of Sulfur.  

ERIC Educational Resources Information Center

Shows how a common demonstration that consists of slowly heating sulfur powder in a test tube to illustrate sulfur's allotropic modifications can convince students of conclusions about the moon Io which they often find surprising. Describes the demonstration in full. (Author/MM)

McCarty, Jillian L.; Dragojlovic, Veljko

2002-01-01

170

Posttranslational modification and microtubule stability  

Microsoft Academic Search

We have probed the relationship between tubulin posttranslational modification and microtubule stability, using a variation of the antibody-blocking technique. In human retinoblastoma cells we find that acetylated and detyrosinated microtubules represent congruent subsets of the cells' total microtubules. We also find that stable microtubules defined as those that had not undergone polymerization within 1 h after in- jection of biotin-tubulin

Eric Schulze; David J. Asai; Jeannette Chloe Bulinski; Marc Kirschner

1987-01-01

171

Plasma surface modification of polymers  

NASA Technical Reports Server (NTRS)

Thin plasma polymerization films are discussed from the viewpoint of simplicity in production stages. The application of selective, absorbent films and films used in selective permeability was tested. The types of surface modification of polymers discussed are: (1) plasma etching, (2) surface coating by plasma polymerized thin films, and (3) plasma activation surface graft polymerization.

Hirotsu, T.

1980-01-01

172

Enzymes for Polymer Surface Modification  

Microsoft Academic Search

During the recent years, various bacteria and fungi have been investigated concerning their ability to degrade artificial\\u000a polymers. This chapter reviews recent work on enzymes used for hydrolysis\\/oxidation of synthetic polymers and discusses their\\u000a use in polymer surface modification.

G. Fischer-Colbrie; S. Heumann; G. Guebitz

173

Field Experimentation in Weather Modification  

Microsoft Academic Search

Weather modification provides a fertile field for interaction and collaboration between meteorologists and statisticians. Cloud seeding experiments, including Project Whitetop, provide a background for illustrating some of the statistical issues in meteorological field experimentation and for exposing some of the difficulties that can arise when meteorologists and statisticians look at the same experiments from different points of view. Several specific

Roscoe R. Braham Jr

1979-01-01

174

Optical coherence tomography assessment of calcified plaque modification after rotational atherectomy.  

PubMed

Rotational atherectomy (RA) facilitates stent delivery in highly calcified coronary plaques (CCP). However, lesion ablation by RA in angulated segments may be affected by guidewire bias, leading to a non-uniform plaque modification. Intravascular optical coherence tomography (iOCT) is the highest resolution (?10 ?m axial) intravascular imaging modality available for clinical use; furthermore, near infrared light easily penetrates calcium, with significantly fewer artifacts, including no "blooming effect" as seen by intravascular ultrasound. Therefore, it may pose as a unique tool for serial calcium quantification, as related in this article with pre- and post-RA assessment, allowing accurate characterization of plaque modification, as well as quality of stent deployment. The effects of guidewire bias in the debulking process have not been well documented by iOCT. We present a case of lesion preparation by RA affected by guidewire bias in which iOCT revealed unique insights into CCP modification. PMID:22045685

Attizzani, Guilherme F; Patrício, Lino; Bezerra, Hiram G

2013-02-01

175

Some unique superconductive Properties of Cuprates  

NASA Astrophysics Data System (ADS)

Copper oxides are the only materials that show transition temperatures, Tc, above the boiling point of liquid nitrogen, with a maximum Tmc of 162 K under pressure. Their structure is layered, with one to several CuO2 planes, and upon hole doping, their transition temperature follows a dome-shaped curve with a maximum at Tmc. In the underdoped regime, i.e., below Tmc, a pseudogap T* is found, with T* always being larger than Tc, a property unique to the copper oxides [1]. In the superconducting state, Cooper pairs (two holes with antiparallel spins) are formed that exhibit coherence lengths on the order of a lattice distance in the CuO2 plane and one order of magnitude less perpendicular to it. Their macroscopic wave function is parallel to the CuO2 plane near 100% d at their surface, but only 75% d and 25 % s in the bulk, and near 100% s perpendicular to the plane in YBCO. There are two gaps with the same Tc [2]. As function of doping, the oxygen isotope effect is novel and can be quantitatively accounted for by a two-band vibronic theory [3] near Tmc, and underdoped below it till Tc = 0 with by a formula valid for (bi)polarons [4]. These cuprates are intrinsically heterogeneous in a dynamic way. In terms of quasiparticles, Jahn-Teller bipolarons are present at low doping, and aggregate upon cooling [1], so that probably ramified clusters and/or stripes are formed, leading over to a more Fermi-liquid-type behavior at large carrier concentrations above Tmc.

Müller, K. A.

2013-04-01

176

Pseudouridine modification in Caenorhabditis elegans spliceosomal snRNAs: unique modifications are found in regions involved in snRNA-snRNA interactions  

Microsoft Academic Search

BACKGROUND: Pseudouridine (?) is an abundant modified nucleoside in RNA and a number of studies have shown that the presence of ? affects RNA structure and function. The positions of ? in spliceosomal small nuclear RNAs (snRNAs) have been determined for a number of species but not for the snRNAs from Caenorhabditis elegans (C. elegans), a popular experimental model system

Jeffrey R Patton; Richard W Padgett

2005-01-01

177

Note On The Guttman-Harris Uniqueness Estimate  

ERIC Educational Resources Information Center

It is shown that, under very general conditions, uniqueness estimates proposed independently by Guttman (1957) and by Harris (1963) provide tighter upper bounds on the unknown uniqueness values of factor analysis than do existing estimates. (Editor)

Meyer, Edward P.

1973-01-01

178

Existence, Uniqueness and Continuity of Solutions of Integral Equations.  

National Technical Information Service (NTIS)

The objective of this paper is to present a number of theorems concerning the existence, uniqueness and continuity of solutions. The basic techniques for deriving existence and uniqueness criteria consist of certain fixed points theorems and comparison th...

R. K. Miller G. R. Sell

1968-01-01

179

Comprehensive Analysis of Protein Modifications by Top-down Mass Spectrometry  

PubMed Central

Mass spectrometry (MS)-based proteomics is playing an increasingly important role in cardiovascular research. Proteomics includes not only identification and quantification of proteins, but also the characterization of protein modifications such as post-translational modifications and sequence variants. The conventional bottom-up approach, involving proteolytic digestion of proteins into small peptides prior to MS analysis, is routinely used for protein identification and quantification with high throughput and automation. Nevertheless, it has limitations in the analysis of protein modifications mainly due to the partial sequence coverage and loss of connections among modifications on disparate portions of a protein. An alternative approach, top-down MS, has emerged as a powerful tool for the analysis of protein modifications. The top-down approach analyzes whole proteins directly, providing a “bird’s eye” view of all existing modifications. Subsequently, each modified protein form can be isolated and fragmented in the mass spectrometer to locate the modification site. The incorporation of the non-ergodic dissociation methods such as electron capture dissociation (ECD) greatly enhances the top-down capabilities. ECD is especially useful for mapping labile post-translational modifications which are well-preserved during the ECD fragmentation process. Top-down MS with ECD has been successfully applied to cardiovascular research with the unique advantages in unraveling the molecular complexity, quantifying modified protein forms, complete mapping of modifications with full sequence coverage, discovering unexpected modifications, and identifying and quantifying positional isomers and determining the order of multiple modifications. Nevertheless, top-down MS still needs to overcome some technical challenges to realize its full potential. Herein, we reviewed the advantages and challenges of top-down methodology with a focus on its application in cardiovascular research.

Zhang, Han; Ge, Ying

2012-01-01

180

Dramatic colour changes in a bird of paradise caused by uniquely structured breast feather barbules  

PubMed Central

The breast-plate plumage of male Lawes' parotia (Parotia lawesii) produces dramatic colour changes when this bird of paradise displays on its forest-floor lek. We show that this effect is achieved not solely by the iridescence—that is an angular-dependent spectral shift of the reflected light—which is inherent in structural coloration, but is based on a unique anatomical modification of the breast-feather barbule. The barbules have a segmental structure, and in common with many other iridescent feathers, they contain stacked melanin rodlets surrounded by a keratin film. The unique property of the parotia barbules is their boomerang-like cross section. This allows each barbule to work as three coloured mirrors: a yellow-orange reflector in the plane of the feather, and two symmetrically positioned bluish reflectors at respective angles of about 30°. Movement during the parotia's courtship displays thereby achieves much larger and more abrupt colour changes than is possible with ordinary iridescent plumage. To our knowledge, this is the first example of multiple thin film or multi-layer reflectors incorporated in a single structure (engineered or biological). It nicely illustrates how subtle modification of the basic feather structure can achieve novel visual effects. The fact that the parotia's breast feathers seem to be specifically adapted to give much stronger colour changes than normal structural coloration implies that colour change is important in their courtship display.

Stavenga, Doekele G.; Leertouwer, Hein L.; Marshall, N. Justin; Osorio, Daniel

2011-01-01

181

Do pediatric hospitalizations have a unique geography?  

PubMed Central

Background In the U.S. small-area health services research studies are often based on the hospital service areas (HSAs) defined by the Dartmouth Atlas of Healthcare project. These areas are based on the geographic origins of Medicare Part A hospital patients, the great majority of whom are seniors. It is reasonable to question whether the geographic system so defined is appropriate for health services research for all ages, particularly for children, who have a very different system of healthcare financing and provision in the U.S. Methods This article assesses the need for a unique system of HSAs to support pediatric small-area analyses. It is a cross-sectional analysis of California hospital discharges for two age groups – non-newborns 0–17 years old, and seniors. The measure of interest was index of localization, which is the percentage of HSA residents hospitalized in their home HSA. Indices were computed separately for each age group, and index agreement was assessed for 219 of the state's HSAs. We examined the effect of local pediatric inpatient volume and pediatric inpatient resources on the divergence of the age group indices. We also created a new system of HSAs based solely on pediatric patient origins, and visually compared maps of the traditional and the new system. Results The mean localization index for pediatric discharges was 20 percentage points lower than for Medicare cases, indicating a poorer fit of the traditional geographic system for children. The volume of pediatric cases did not appear to be associated with the magnitude of index divergence between the two age groups. Pediatric medical and surgical case subgroups gave very similar results, and both groups differed substantially from seniors. Location of children's hospitals and local pediatric bed supply were associated with Medicare-pediatric divergence. There was little visual correspondence between the maps of traditional and pediatric-specific HSAs. Conclusion Children and seniors have significantly different geographic patterns of hospitalization in California. Medicare-based HSAs may not be appropriate for all age groups and service types throughout the U.S.

Guagliardo, Mark F; Jablonski, Kathleen A; Joseph, Jill G; Goodman, David C

2004-01-01

182

Kerala: a unique model of development.  

PubMed

This article capsules health in terms of morbidity, mortality, and maternal and child health; sex ratios, and population density in Kerala state in India from a more expanded report. Kerala state is known for its highly literate and female literate, and poor income population, but its well advanced state of demographic transition. There is a declining population growth rate, a high average marriage age, a low fertility rate, and a high degree of population mobility. One of the unique features of Kerala is the high female literacy, and the favorable position of women in decision making and a matrilineal inheritance mode. The rights of the poor and underprivileged have been upheld. The largest part of government revenue is spent on education followed by health. Traditional healing systems such the ayurveda are strong in Kerala, and Christian missionaries have contributed to a caring tradition. Morbidity is high and mortality is low because medical interventions have affected morality only. The reduction of poverty and environmentally related diseases has not been accomplished inspite of land reform, mass schooling, and general egalitarian policies. Mortality declines and a decline in birth rates have lead to a more adult and aged population, which increases the prevalence of chronic degenerative diseases. Historically, the death rate in Kerala was always lower (25/1000 in 1930 and 6.4 in 1986). The gains in mortality were made in reducing infant mortality (27/1000), which is 4 times less than India as a whole and comparable to Korea, Panama, Yugoslavia, Sri Lanka, and Colombia. Lower female mortality occurs in the 0-4 years. Life expectancy which was the same as India's in 1930 is currently 12 years higher than India's. Females have a higher expectation of life. The sex ratio in 1981 was 1032 compared to India's of 935. Kerala had almost replacement level in 1985. The crude birth rate is 21 versus 32 for India. In addition to the decline in death rates of those 5 years, the 45 year population has also experienced a decline. In the 15-24 age group, the most common cause of death is suicides (53/100,000 or 25% of all deaths) and accidents. Further study is needed to examine the determinants. 76% have hospital births. Home deliveries are related to low social class. Pregnancy risk is avoided in higher groups. Child health has been improved by the rise in marriage age, the small family norm, better women's education, greater decision making for women, and health care availability: all socioeconomic factors. PMID:12317117

Kannan, K P; Thankappan, K R; Ramankutty, V; Aravindan, K P

1991-12-01

183

Thiol dioxygenases: unique families of cupin proteins.  

PubMed

Proteins in the cupin superfamily have a wide range of biological functions in archaea, bacteria and eukaryotes. Although proteins in the cupin superfamily show very low overall sequence similarity, they all contain two short but partially conserved cupin sequence motifs separated by a less conserved intermotif region that varies both in length and amino acid sequence. Furthermore, these proteins all share a common architecture described as a six-stranded ?-barrel core, and this canonical cupin or "jelly roll" ?-barrel is formed with cupin motif 1, the intermotif region, and cupin motif 2 each forming two of the core six ?-strands in the folded protein structure. The recently obtained crystal structures of cysteine dioxygenase (CDO), with contains conserved cupin motifs, show that it has the predicted canonical cupin ?-barrel fold. Although there had been no reports of CDO activity in prokaryotes, we identified a number of bacterial cupin proteins of unknown function that share low similarity with mammalian CDO and that conserve many residues in the active-site pocket of CDO. Putative bacterial CDOs predicted to have CDO activity were shown to have similar substrate specificity and kinetic parameters as eukaryotic CDOs. Information gleaned from crystal structures of mammalian CDO along with sequence information for homologs shown to have CDO activity facilitated the identification of a CDO family fingerprint motif. One key feature of the CDO fingerprint motif is that the canonical metal-binding glutamate residue in cupin motif 1 is replaced by a cysteine (in mammalian CDOs) or by a glycine (bacterial CDOs). The recent report that some putative bacterial CDO homologs are actually 3-mercaptopropionate dioxygenases suggests that the CDO family may include proteins with specificities for other thiol substrates. A paralog of CDO in mammals was also identified and shown to be the other mammalian thiol dioxygenase, cysteamine dioxygenase (ADO). A tentative fingerprint motif for ADOs, or DUF1637 family members, is proposed. In ADOs, the conserved glutamate residue in cupin motif 1 is replaced by either glycine or valine. Both ADOs and CDOs appear to represent unique clades within the cupin superfamily. PMID:20195658

Stipanuk, Martha H; Simmons, Chad R; Karplus, P Andrew; Dominy, John E

2011-06-01

184

Medium Modification of Vector Mesons  

SciTech Connect

The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift in mass and/or a change of width are predicted at normal nuclear density. Photoproduction of vector mesons off nuclei have been performed at different laboratories. The properties of the ?, ? and ? mesons are investigated either directly by measuring their mass spectra or indirectly through transparency ratios. The latest results regarding medium modifications of the vector mesons in the nuclear medium will be discussed.

Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour

2011-03-01

185

Chromatin modifications associated with diabetes.  

PubMed

Accelerated rates of vascular complications are associated with diabetes mellitus. Environmental factors including hyperglycaemia contribute to the progression of diabetic complications. Epidemiological and experimental animal studies identified poor glycaemic control as a major contributor to the development of complications. These studies suggest that early exposure to hyperglycaemia can instigate the development of complications that present later in the progression of the disease, despite improved glycaemic control. Recent experiments reveal a striking commonality associated with gene-activating hyperglycaemic events and chromatin modification. The best characterised to date are associated with the chemical changes of amino-terminal tails of histone H3. Enzymes that write specified histone tail modifications are not well understood in models of hyperglycaemia and metabolic memory as well as human diabetes. The best-characterised enzyme is the lysine specific Set7 methyltransferase. The contribution of Set7 to the aetiology of diabetic complications may extend to other transcriptional events through methylation of non-histone substrates. PMID:22639343

Keating, Samuel T; El-Osta, Assam

2012-08-01

186

Cradle modification for hydraulic ram  

SciTech Connect

The analysis of the cradle hydraulic system considers stress, weld strength, and hydraulic forces required to lift and support the cradle/pump assembly. The stress and weld strength of the cradle modifications is evaluated to ensure that they meet the requirements of the American Institute for Steel Construction (AISC 1989). The hydraulic forces are evaluated to ensure that the hydraulic system is capable of rotating the cradle and pump assembly to the vertical position (between 70{degrees} and 90{degrees}).

Koons, B.M.

1995-03-02

187

An overview of chromatin modifications.  

PubMed

The last 15 years have witnessed tremendous progress in elucidating the roles of chromatin modifications in transcription regulation, DNA repair, replication, recombination, and other genomic processes. In this issue of Biopolymers, a series of reviews will summarize recent advances in our understanding of chromatin modifying enzymes and explore unresolved questions with respect to their regulation and functions in gene expression and other nuclear processes. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 95-97, 2013. PMID:23175384

Fick, Robert J; Trievel, Raymond C

2013-02-01

188

Femtosecond laser modification of glass  

Microsoft Academic Search

Tight focusing of ultrashort (?100fs) infrared laser pulses of moderate energy (typically 1–10?J) into a glass results in very high, localized (in space and time) intensities, in excess of 1014W\\/cm2. Under these conditions the laser–materials interaction becomes highly nonlinear, resulting in permanent modification of the material. By precisely controlling sample position and movement it is possible to optically ‘write’ three-dimensional

D. M. Krol

2008-01-01

189

Dual-aptamer modification generates a unique interface for highly sensitive and specific electrochemical detection of tumor cells.  

PubMed

Because circulating tumor cells (CTCs) have been proven to be an important clue of the tumor metastasis, their detection thus plays a pivotal role in the diagnosis and prognosis of cancer. Herein, we fabricate an electrochemical sensor by directly conjugating two cell-specific aptamers, TLS1c and TLS11a, which specifically recognize MEAR cancer cells, to the surface of a glassy carbon electrode (GCE) via the formation of amide bonds. The two aptamers are simultaneously conjugated to the GCE surface via precisely controlled linkers: TLS1c through a flexible linker (a single-stranded DNA T15; ss-TLS1c) and TLS11a through a rigid linker (a double-stranded DNA T15/A15; ds-TLS11a). It is found that such ss-TLS1c/ds-TLS11a dual-modified GCEs show greatly improved sensitivity in comparison with those modified with a single type of aptamer alone or ds-TLS1c/ds-TLS11a with both rigid linkers, suggesting that our optimized, rationally designed electrode-aptamer biosensing interface may enable better recognition and thus more sensitive detection of tumor cells. Through the utilization of this dual-aptamer-modified GCE, as few as a single MEAR cell in 10(9) whole blood cells can be successfully detected with a linear range of 1-14 MEAR cells. Our work demonstrates a rather simple yet well-designed and ultrasensitive tumor cell detection method based on the cell-specific aptamer-modified GCE, showing a promising potential for further CTC-related clinical applications. PMID:24801611

Qu, Liming; Xu, Jinhai; Tan, Xiaofang; Liu, Zhuang; Xu, Ligeng; Peng, Rui

2014-05-28

190

Epigenetic modifications in rheumatoid arthritis.  

PubMed

Over the last decades, genetic factors for rheumatoid diseases like the HLA haplotypes have been studied extensively. However, during the past years of research, it has become more and more evident that the influence of epigenetic processes on the development of rheumatic diseases is probably as strong as the genetic background of a patient. Epigenetic processes are heritable changes in gene expression without alteration of the nucleotide sequence. Such modifications include chromatin methylation and post-translational modification of histones or other chromatin-associated proteins. The latter comprise the addition of methyl, acetyl, and phosphoryl groups or even larger moieties such as binding of ubiquitin or small ubiquitin-like modifier. The combinatory nature of these processes forms a complex network of epigenetic modifications that regulate gene expression through activation or silencing of genes. This review provides insight into the role of epigenetic alterations in the pathogenesis of rheumatoid arthritis and points out how a better understanding of such mechanisms may lead to novel therapeutic strategies. PMID:18947370

Strietholt, Simon; Maurer, Britta; Peters, Marvin A; Pap, Thomas; Gay, Steffen

2008-01-01

191

Modelling of analytical peaks: peaks modifications.  

PubMed

The basic principles of symmetric peaks modifications are considered in this work. Four types of modifications--two symmetric and two asymmetric are considered in detail. Double sequent peak modification was taken as example. The dependences of peak shape parameters on modification parameters were obtained for considered examples of modifications of three basic peaks. The methods of obtaining of common sequent modifications and techniques of suitable result function choice for adequate description of analytical signal series are developed. The approximation of groups of stripping voltammetry and chromatographic peaks with some single, double and triple modifications of elementary peaks has been get. The appreciable increasing of adequacy in description of more complicated modifications was shown. PMID:17386462

Romanenko, S V; Stromberg, A G

2007-01-01

192

Adaptive Control with Reference Model Modification.  

National Technical Information Service (NTIS)

This paper presents a modification of the conventional model reference adaptive control (MRAC) architecture in order to improve transient performance of the input and output signals of uncertain systems. A simple modification of the reference model is pro...

K. Krishnakumar V. Stepanyan

2012-01-01

193

Weather Modification Information for the Minnesota Legislature.  

National Technical Information Service (NTIS)

During the 1977 session of the Minnesota Legislature, a bill regulating weather modification was passed. In the course of deliberation over weather modification legislation, several legislators requested information and analysis from the Science and Techn...

1977-01-01

194

Weather Modification as a Weapon of War.  

National Technical Information Service (NTIS)

The basic question addressed in this paper is whether or not weather modification can be used as a weapon of war. Possible tactical and strategic uses of weather modification were examined. The national security implications and arguments for and against ...

P. L. Blackburn

1975-01-01

195

Cross-regulation of histone modifications  

Microsoft Academic Search

Histones undergo several different post-translational modifications that control a variety of physiological processes. These covalent modifications show substantial cross-regulation, providing a wealth of regulatory potential. New insights into the communication between modifications on histones have emerged in recent years. This review assesses the current understanding of cross-regulation of histone modifications and identifies future questions to be addressed in this field.

John A Latham; Sharon Y R Dent

2007-01-01

196

Energy conservation potential of surface modification technologies  

SciTech Connect

This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

Le, H.K.; Horne, D.M.; Silberglitt, R.S.

1985-09-01

197

Modification Of Gear Teeth To Reduce Vibrations  

NASA Technical Reports Server (NTRS)

Computer simulations yield data useful in designing for low noise. Effects of modifications in shape of gear teeth upon static transmission error and dynamic loading of gears now analyzed systematically. Design curves generated by conducting numerical simulations of dynamic effects at successive incremental modifications of gear systems operated at various applied loads. Modifications that result in minimum dynamic effect determined from design curves.

Townsend, Dennis P.; Oswald, Fred B.; Lin, Hsiang Hsi

1990-01-01

198

Surface modification by plasma immersion ion processing  

Microsoft Academic Search

Los Alamos National Laboratory is actively researching a surface modification technique called plasma immersion ion processing (PIIP). PIIP is the latest innovation of the plasma source ion implantation (PSII) approach to surface modification. Like PSII, PIIP allows the modification of large areas and non-planar surface geometries, however PIIP is primarily a coating deposition technology rather than solely an ion implantation

Kevin C. Walter; D. H. Lee; X. M. He; N. P. Baker; Michael Nastasi; C. P. Munson; W. K. Scarborough; M. Tuszewski; B. P. Wood

1998-01-01

199

The Public Decides about Weather Modification  

Microsoft Academic Search

Planned weather modification is a potentially significant phenomenon being introduced in many area of this and other countries. Evidence is beginning to accumulate suggesting that where organized resistance persists over a period of time, weather modification efforts are in fact halted. The paper briefly outlines the history of weather modification in the United States; research findings on the social aspects

Barbara C. Farhar

1977-01-01

200

Modification of Nanostructures via Laser Processing  

NASA Astrophysics Data System (ADS)

Modification of nanostructures via laser processing is of great interest for a wide range of applications such as aerospace and the storage of nuclear waste. The primary goal of this dissertation is to improve the understanding of nanostructures through two primary routes: the modification of aerogels and pulsed laser ablation in ethanol. A new class of materials, patterned aerogels, was fabricated by photopolymerizing selected regions of homogeneous aerogel monoliths using visible light. The characterization and fabrication of functionally graded, cellular and compositionally anisotropic aerogels and ceramics is discussed. Visible light was utilized due to it's minimal absorption and scattering by organic molecules and oxide nanoparticles within wet gels. This allowed for the fabrication of deeply penetrating, well resolved patterns. Similarly, nanoporous monoliths with a typical aerogel core and a mechanically robust exterior ceramic layer were synthesized from silica aerogels cross-linked with polyacrylonitrile. Simple variations of the exposure geometry allowed fabrication of a wide variety of anisotropic materials without requiring layering or bonding. Nanoparticle solutions were prepared by laser ablation of metal foils (Fe and Mo) in ethanol. Ablation of Fe generated Fe3O4 and Fe3C nanoparticles which were superparamagnetic with a saturation magnetization Ms = 124 emu/g. Zero field cooled (ZFC) measurements collected at an applied field of 50 Oe displayed a maximum magnetic susceptibility at 120 K with a broad distribution. Field cooled (FC) measurements showed a thermal hysteresis indicative of temperature dependent magnetic viscosity. Pulsed laser ablation of a Mo foil in ethanol generated inhomogeneous nanoparticles where Mo and MoC coexisted within the same aggregate. Formation of these unique nanoparticles is likely due to phase separation that occurs when a high temperature carbide phase cools after the laser pulse terminates. Similarly, magnetic nanoparticle suspensions were generated by pulsed laser ablation of Fe and Mo in ethanol. The formation of several carbide phases with no discernable alloy formation was seen. A decrease in magnetization with a decrease in Fe concentration was seen which was reconciled with the decreased Fe content in the system. However, at Fe concentrations below ˜ 40%, an increase in Ms and Hc was observed which was reconciled with the disappearance of the epsilon--Fe 3C. TEM analysis showed the formation of core-shell nanoparticles and Energy Filtered TEM showed the distribution of Fe-based nanoparticles in the suspensions.

Franzel, Louis Avery

201

Modification of Nanostructures via Laser Processing  

NASA Astrophysics Data System (ADS)

Modification of nanostructures via laser processing is of great interest for a wide range of applications such as aerospace and the storage of nuclear waste. The primary goal of this dissertation is to improve the understanding of nanostructures through two primary routes: the modification of aerogels and pulsed laser ablation in ethanol. A new class of materials, patterned aerogels, was fabricated by photopolymerizing selected regions of homogeneous aerogel monoliths using visible light. The characterization and fabrication of functionally graded, cellular and compositionally anisotropic aerogels and ceramics is discussed. Visible light was utilized due to it's minimal absorption and scattering by organic molecules and oxide nanoparticles within wet gels. This allowed for the fabrication of deeply penetrating, well resolved patterns. Similarly, nanoporous monoliths with a typical aerogel core and a mechanically robust exterior ceramic layer were synthesized from silica aerogels cross-linked with polyacrylonitrile. Simple variations of the exposure geometry allowed fabrication of a wide variety of anisotropic materials without requiring layering or bonding. Nanoparticle solutions were prepared by laser ablation of metal foils (Fe and Mo) in ethanol. Ablation of Fe generated Fe3O4 and Fe3C nanoparticles which were superparamagnetic with a saturation magnetization Ms = 124 emu/g. Zero field cooled (ZFC) measurements collected at an applied field of 50 Oe displayed a maximum magnetic susceptibility at 120 K with a broad distribution. Field cooled (FC) measurements showed a thermal hysteresis indicative of temperature dependent magnetic viscosity. Pulsed laser ablation of a Mo foil in ethanol generated inhomogeneous nanoparticles where Mo and MoC coexisted within the same aggregate. Formation of these unique nanoparticles is likely due to phase separation that occurs when a high temperature carbide phase cools after the laser pulse terminates. Similarly, magnetic nanoparticle suspensions were generated by pulsed laser ablation of Fe and Mo in ethanol. The formation of several carbide phases with no discernable alloy formation was seen. A decrease in magnetization with a decrease in Fe concentration was seen which was reconciled with the decreased Fe content in the system. However, at Fe concentrations below ˜ 40%, an increase in Ms and Hc was observed which was reconciled with the disappearance of the epsilon--Fe3C. TEM analysis showed the formation of core-shell nanoparticles and Energy Filtered TEM showed the distribution of Fe-based nanoparticles in the suspensions.

Franzel, Louis Avery

202

ROSAT Discovers Unique, Distant Cluster of Galaxies  

NASA Astrophysics Data System (ADS)

Brightest X-ray Cluster Acts as Strong Gravitational Lens Based on exciting new data obtained with the ROSAT X-ray satellite and a ground-based telescope at the ESO La Silla Observatory, a team of European astronomers [2] has just discovered a very distant cluster of galaxies with unique properties. It emits the strongest X-ray emission of any cluster ever observed by ROSAT and is accompanied by two extraordinarily luminous arcs that represent the gravitationally deflected images of even more distant objects. The combination of these unusual characteristics makes this cluster, now known as RXJ1347.5-1145, a most interesting object for further cosmological studies. DISCOVERY AND FOLLOW-UP OBSERVATIONS This strange cluster of galaxies was discovered during the All Sky Survey with the ROSAT X-ray satellite as a moderately intense X-ray source in the constellation of Virgo. It could not be identified with any already known object and additional ground-based observations were therefore soon after performed with the Max-Planck-Society/ESO 2.2-metre telescope at the La Silla observatory in Chile. These observations took place within a large--scale redshift survey of X-ray clusters of galaxies detected by the ROSAT All Sky Survey, a so-called ``ESO Key Programme'' led by astronomers from the Max-Planck-Institut fur Extraterrestrische Physik and the Osservatorio Astronomico di Brera. The main aim of this programme is to identify cluster X-ray sources, to determine the distance to the X-ray emitting clusters and to investigate their overall properties. These observations permitted to measure the redshift of the RXJ1347.5-1145 cluster as z = 0.45, i.e. it moves away from us with a velocity (about 106,000 km/sec) equal to about one-third of the velocity of light. This is an effect of the general expansion of the universe and it allows to determine the distance as about 5,000 million light-years (assuming a Hubble constant of 75 km/sec/Mpc). In other words, we see these galaxies as they were 5,000 million years ago. Knowing the intensity of the X-ray emission as measured by ROSAT and also the distance, the astronomers were then able to estimate the total X-ray energy emitted by this cluster. It was found to be extremely high [3], in fact higher than that of any other cluster ever observed by ROSAT. It amounts to no less than 1.5 million million times the total energy emitted by the Sun. It is believed that this strong X-ray emission originates in a hot gas located between the galaxies in the cluster. The high temperature indicates that the components of the gas move very rapidly; this is related to the strong gravitational field within the cluster. THE GRAVITATIONAL ARCS To their great surprise and delight, the astronomers also discovered two bright arcs, 5 - 6 arcseconds long and symmetrically placed about 35 arcseconds to the North-East and South-West of the brightest galaxies in the cluster (see the photo). They were detected on exposures of only 3 minutes duration with the 2.2-metre telescope and are among the brightest such arcs ever found. At the indicated distance, the arcs are situated at a projected distance of about 500,000 light-years from the centre of the cluster. It is an interesting possibility that the two arcs may in fact be two images of the same, very distant galaxy, that is situated far beyond RXJ1347.5-1145 and whose light has been bent and split by this cluster's strong gravitational field. This strange phenomenon was first discovered in the late 1970's and is referred to as gravitational lensing. Quite a few examples are now known, in most cases in the form of double or multiple images of quasars. About three dozen cases involve well visible galaxy clusters and elongated arcs, but few, if any, of these arcs are as bright as those seen in the present cluster. This particular arc configuration enables a very accurate determination of the total mass of the cluster, once the distance of the background galaxy has been measured (by obtaining spectra of the arcs and measuring their redshift). The masses of galaxy clus

1995-06-01

203

Surface modifications of influenza proteins upon virus inactivation by ?-propiolactone.  

PubMed

Inactivation of intact influenza viruses using formaldehyde or ?-propiolactone (BPL) is essential for vaccine production and safety. The extent of chemical modifications of such reagents on viral proteins needs to be extensively investigated to better control the reactions and quality of vaccines. We have evaluated the effect of BPL inactivation on two candidate re-assortant vaccines (NIBRG-121xp and NYMC-X181A) derived from A/California/07/2009 pandemic influenza viruses using high-resolution FT-ICR MS-based proteomic approaches. We report here an ultra performance LC MS/MS method for determining full-length protein sequences of hemagglutinin and neuraminidase through protein delipidation, various enzymatic digestions, and subsequent mass spectrometric analyses of the proteolytic peptides. We also demonstrate the ability to reliably identify hundreds of unique sites modified by propiolactone on the surface of glycoprotein antigens. The location of these modifications correlated with changes to protein folding, conformation, and stability, but demonstrated no effect on protein disulfide linkages. In some cases, these modifications resulted in suppression of protein function, an effect that correlated with the degree of change of the modified amino acids' side chain length and polarity. PMID:24123778

She, Yi-Min; Cheng, Keding; Farnsworth, Aaron; Li, Xuguang; Cyr, Terry D

2013-12-01

204

Key advances in the chemical modification of nanocelluloses.  

PubMed

Nanocelluloses, including nanocrystalline cellulose, nanofibrillated cellulose and bacterial cellulose nanofibers, have become fascinating building blocks for the design of new biomaterials. Derived from the must abundant and renewable biopolymer, they are drawing a tremendous level of attention, which certainly will continue to grow in the future driven by the sustainability trend. This growing interest is related to their unsurpassed quintessential physical and chemical properties. Yet, owing to their hydrophilic nature, their utilization is restricted to applications involving hydrophilic or polar media, which limits their exploitation. With the presence of a large number of chemical functionalities within their structure, these building blocks provide a unique platform for significant surface modification through various chemistries. These chemical modifications are prerequisite, sometimes unavoidable, to adapt the interfacial properties of nanocellulose substrates or adjust their hydrophilic-hydrophobic balance. Therefore, various chemistries have been developed aiming to surface-modify these nano-sized substrates in order to confer to them specific properties, extending therefore their use to highly sophisticated applications. This review collocates current knowledge in the research and development of nanocelluloses and emphasizes more particularly on the chemical modification routes developed so far for their functionalization. PMID:24316693

Habibi, Youssef

2014-03-01

205

Effect of flap modifications on human FEN1 cleavage.  

PubMed

The flap endonuclease, FEN1, plays a critical role in DNA replication and repair. Human FEN1 exhibits both a 5' to 3' exonucleolytic and a structure-specific endonucleolytic activity. On primer-template substrates containing an unannealed 5'-tail, or flap structure, FEN1 employs a unique mechanism to cleave at the point of annealing, releasing the 5'-tail intact. FEN1 appears to track along the full length of the flap from the 5'-end to the point of cleavage. Substrates containing structural modifications to the flap have been used to explore the mechanism of tracking. To determine whether the nuclease must recognize a succession of nucleotides on the flap, chemical linkers were used to replace an interior nucleotide. The nuclease could readily traverse this site. The footprint of the nuclease at the time of cleavage does not extend beyond 25 nucleotides on the flap. Eleven-nucleotide branches attached to the flap beyond the footprinted region do not prevent cleavage. Single- or double-thymine dimers also allow cleavage. cis-Platinum adducts outside the protected region are moderately inhibitory. Platinum-modified branch structures are completely inert to cleavage. These results show that some flap modifications can prevent or inhibit tracking, but the tracking mechanism tolerates a variety of flap modifications. FEN1 has a flexible loop structure through which the flap has been proposed to thread. However, efficient cleavage of branched structures is inconsistent with threading the flap through a hole in the protein. PMID:10529210

Bornarth, C J; Ranalli, T A; Henricksen, L A; Wahl, A F; Bambara, R A

1999-10-01

206

Materials Modification in Nanotechnology: Oxidation  

NSDL National Science Digital Library

This PowerPoint created and presented by the Nanotechnology Applications and Career Knowledge (NACK) Center introduces students to oxidation. It goes over the various types of oxide â native, gate, field, etc. It discusses dry vs. wet oxidation, high pressure oxidation, chemical vapor deposition and has a section on modifying dielectric constant. This is a great resource for any classroom looking at nanofabrication modifications. This and all other valuable resources from the NACK Center require a fast, easy, free log-in.

2010-03-22

207

Using Java to Generate Globally Unique Identifiers for DICOM Objects  

Microsoft Academic Search

Digital imaging and communication in medicine (DICOM) specifies that all DICOM objects have globally unique identifiers (UIDs).\\u000a Creating these UIDs can be a difficult task due to the variety of techniques in use and the requirement to ensure global uniqueness.\\u000a We present a simple technique of combining a root organization identifier, assigned descriptive identifiers, and JAVA generated\\u000a unique identifiers to

Aaron W. C. Kamauu; Scott L. Duvall; David E. Avrin

2009-01-01

208

Aberrant histone modification in endometriosis.  

PubMed

Accumulating evidence suggests that epigenetic aberrations play definite roles in the pathogenesis of endometriosis. These include aberrations in genomic DNA methylation, microRNA expression, and histone modification. The aberrant histone modification status and the aberrant expression of histone deacetylases, which regulate histone acetylation, in endometriosis are the focus of this review. Herein, we summarize the recent studies in the following areas: (i) hyperacetylation of histones located in the promoter lesions of G-protein-coupled estrogen receptor 1, steroidogenic factor-1, and hypoxia-inducible factor-1 alpha genes and (ii) hypoacetylation of histones located in the promoter lesions of estrogen receptor alpha, homeobox A10, CCAAT/enhancer-binding protein alpha, p16(INK4a), p21(Waf1/Cip1), p27(Kip1), checkpoint kinase 2, death receptor 6, and E-cadherin genes. Further research from the viewpoint of epigenetics may lead to the identification of the candidate molecules that are aberrantly expressed in endometriosis and may help elucidate the pathogenesis of this disease. In addition, epigenetic drugs (including histone deacetylase inhibitors) show promise for the treatment of endometriosis by amending the expression of these epigenetically dysregulated genes. PMID:24896345

Nasu, Kaei; Kawano, Yukie; Kai, Kentaro; Aoyagi, Yoko; Abe, Wakana; Okamoto, Mamiko; Narahara, Hisashi

2014-01-01

209

Surface modification of graphitic foam  

NASA Astrophysics Data System (ADS)

This article discusses surface-related issues and possible modification approaches in high-porosity graphitic foam. The microcellular solid is made of graphitic carbon walls, ligaments, and beams supporting a network of interconnected pores. This makes the exposed surface area very high and its understanding a necessity for most applications. Graphitic planes are seen to be stacked at various orientations with respect to exposed surfaces. Therefore, a simplified analytical model that assumes ``random'' graphitic planes forming a three-dimensional array of tetrahedral cells may be an appropriate approximation. The influence of oxidizing chemicals such as nitric acid and hydrogen peroxide on surface properties has been studied using electron microscopy, photoelectron spectroscopy, and water absorption tests. Bulk properties such as density measurements and mechanical tests have been performed in parallel. It is seen that exposure to nitric acid results in an increase in oxygen-containing functional groups on the surface, which may lead to increased infiltration of polar matrix fluids such as water and epoxy resins. This possibility is further supported by water absorption studies that show increased water infiltration in foam after nitric acid treatment. Electron microscopy and density studies indicate that some surface etching occurs with concentrated nitric acid exposure, but not significant enough to decrease density. Strength of the stand-alone foam is reduced for concentrated nitric acid treatment, but the elastic modulus is unaffected. The scientific significance of these results in terms of future surface modification of microcellular solids has been discussed.

Mukhopadhyay, Sharmila M.; Pulikollu, Rajasekhar V.; Ripberger, Erik; Roy, Ajit K.

2003-01-01

210

Precision teaching's unique legacy from B. F. Skinner  

Microsoft Academic Search

Precision Teaching's unique legacy from B. F. Skinner was the monitoring system of rate of response and the cumulative response recorder. This legacy is unique because the other instructional systems derived from Skinner's work do not use his monitoring method exclusively. Rate of response, cumulative recording and their extension to Precision Teaching's standard celeration charting are briefly described. In addition,

Ogden R. Lindsley

1991-01-01

211

Uniqueness domains and regions of feasible paths for cuspidal manipulators  

Microsoft Academic Search

This paper addresses the kinematics of cuspidal manipulators, i.e., nonredundant manipulators which can change posture without meeting a singularity. It focuses on the uniqueness domains and on the regions of feasible paths in the workspace. For cuspidal manipulators, the uniqueness domains are not the singularity-free regions of the joint space. It is shown that additional surfaces, called characteristic surfaces, separate

Philippe Wenger

2004-01-01

212

The tubular "cookie cutter" bullet: a unique projectile.  

PubMed

Recently marketed PMC (Pan Metal Corporation) Ultramag tubular hollow point ammunition is uniquely constructed with a two-part projectile composed of a tubular copper bullet and a Teflon wad. A fatal gunshot wound with this ammunition is described. A unique radiographic pattern and the results of test firing are also presented. PMID:2262780

Nolte, K B

1990-11-01

213

Harmonic maps and uniqueness of axisymmetric monopole solutions  

NASA Technical Reports Server (NTRS)

The uniqueness of axisymmetric monopole solutions to the Bogomolny equations is studied. The generalized Green identity for harmonic maps is used to prove that the Prasad-Sommerfield solution is the unique axisymmetric one-monopole solution. The multimonopole solutions are also discussed.

Mazur, P. O.; Richter, E.

1985-01-01

214

Uniqueness theorems and ideal structure for Leavitt path algebras  

Microsoft Academic Search

We prove Leavitt path algebra versions of the two uniqueness theorems of graph C?-algebras. We use these uniqueness theorems to analyze the ideal structure of Leavitt path algebras and give necessary and sufficient conditions for their simplicity. We also use these results to give a proof of the fact that for any graph E the Leavitt path algebra LC(E) embeds

Mark Tomforde

2007-01-01

215

Phosphorylation of unique domains of Src family kinases  

PubMed Central

Members of the Src family of kinases (SFKs) are non-receptor tyrosine kinases involved in numerous signal transduction pathways. The catalytic, SH3 and SH2 domains are attached to the membrane-anchoring SH4 domain through the intrinsically disordered “Unique” domains, which exhibit strong sequence divergence among SFK members. In the last decade, structural and biochemical studies have begun to uncover the crucial role of the Unique domain in the regulation of SFK activity. This mini-review discusses what is known about the phosphorylation events taking place on the SFK Unique domains, and their biological relevance. The modulation by phosphorylation of biologically relevant inter- and intra- molecular interactions of Src, as well as the existence of complex phosphorylation/dephosphorylation patterns observed for the Unique domain of Src, reinforces the important functional role of the Unique domain in the regulation mechanisms of the Src kinases and, in a wider context, of intrinsically disordered regions in cellular processes.

Amata, Irene; Maffei, Mariano; Pons, Miquel

2014-01-01

216

Behavior modification in physical therapy.  

PubMed

Behavioral techniques reported to improve ambulation skills among physically handicapped persons include both reward and desensitization procedures. This report describes the application of other behavior modification principles to two patients who resisted physical therapy (PT) designed to educate them in the use of orthopedic assistive devices. Peer modeling was used with case 1, a 2 1/2-year-old girl with complete L4 spina bifida who cried frequently when wearing her brace, and refused to walk except with much assistance. Case 2 was a 21-year-old hemiplegic man seen two years after a severe head injury. Initially, severe tantrum behavior accompanied all demands placed on him. Treatment involved a combination of contingent music for being quiet and contingent aversive auditory feedback for yelling. In both cases clinically significant behavioral changes were observed. Results are discussed with respect to the cost effectiveness of behavioral interventions and the interdisciplinary coordination of rehabilitation team members. PMID:3882077

Gouvier, W D; Richards, J S; Blanton, P D; Janert, K; Rosen, L A; Drabman, R S

1985-02-01

217

Antigenic protein modifications in Ehrlichia  

PubMed Central

To develop effective vaccination strategies againstEhrlichia, we have previously reported developing an animal model of cross-protection in which C57BL/6 mice primed withE. muris were resistant to lethal infection withIxodes ovatus ehrlichia (IOE). Polyclonal antibody produced in mice after priming withE. muris and later injected with IOE-detected antigenic proteins inE. muris and IOE cell lysates. Cross-reaction of antigenic proteins was observed when we probed both theE. muris and IOE cell lysates with IOE andE. muris-specific polyclonal antibody. Analysis of the total proteins ofE. muris and IOE by two dimensional electrophoresis showed that bothE. muris and IOE have the same antigenic proteins. Finally, studies on post-translational protein modifications using a novel technique, Eastern blotting, showed thatE. muris proteins are more lipoylated and glycosylated than those of IOE.

THOMAS, S; THIRUMALAPURA, N; CROSSLEY, E C; ISMAIL, N; WALKER, D H

2009-01-01

218

Laser surface modification of PEEK  

NASA Astrophysics Data System (ADS)

Polyether-ether-ketone (PEEK) is a synthetic thermoplastic polymer with excellent mechanical and chemical properties, which make it attractive for the field of reconstructive surgery. Nevertheless, this material has a poor interfacial biocompatibility due to its large chemical stability which induces poor adhesive bonding properties. The possibilities of enhancing the PEEK adhesive properties by laser treatments have been explored in the past. This paper presents a systematic approach to discern the role of laser irradiation wavelength on the surface modification of PEEK under three laser wavelengths (? = 1064, 532, and 355 nm) with the aim to determine the most adequate processing conditions to increase the roughness and wettability, the main parameters affecting cell adhesion characteristics of implants. Overall results show that the ultraviolet (? = 355 nm) laser radiation is the most suitable one to enhance surface wettability of PEEK.

Riveiro, A.; Soto, R.; Comesaña, R.; Boutinguiza, M.; del Val, J.; Quintero, F.; Lusquiños, F.; Pou, J.

2012-09-01

219

Paper surface modification by lasers  

NASA Astrophysics Data System (ADS)

Lasers can provide a precious tool to conservation process due to their accuracy and the controlled energy they deliver, especially to fragile organic material such as paper. The current study concerns laser modification such as paper cleaning, initially of test papers artificially soiled and then of an original book of the early 20th Century. The test objects were A4 copier paper, newspaper, and paper Whatman No.1056. During the experiments, ink of a pen, pencil and ink from a stamp was mechanically employed on each paper surface. Laser cleaning was applied using a Q-switched Nd:YAG operating at 532 nm and CO2 laser at 10.6 ?m for various fluences. The experimental results were presented by using optical microscopy. Eventually, laser cleaning of ink was performed to a book of 1934, by choosing the best conditions and parameters from cleaning the test samples, like Nd:YAG laser operating at 532 nm.

Zekou, E.; Kotsifaki, D. G.; Serafetinides, A. A.

2010-10-01

220

Histone modifications and cancer: biomarkers of prognosis?  

PubMed

Epigenetic dysregulation is being increasingly recognized as a hallmark of cancer. Post-translational modifications of histones, in particular, are known to play important roles gene expression alterations in cancer development and progression. Given their key involvement in the various stages of carcinogenesis, histone modifications are also being explored as potential biomarkers of disease progression and prognosis. This review will therefore discuss the role of histone modifications in cancer biology and will explore their prognostic potential. PMID:22957310

Chervona, Yana; Costa, Max

2012-01-01

221

Modifications of therapeutic proteins: challenges and prospects  

Microsoft Academic Search

The production of therapeutic proteins is one of the fastest growing sectors of the pharmaceutical industry. However, most\\u000a proteins used in drug therapy require complex post-translational modifications for efficient secretion, drug efficacy and\\u000a stability. Common protein modifications include variable glycosylation, misfolding and aggregation, oxidation of methionine,\\u000a deamidation of asparagine and glutamine, and proteolysis. These modifications not only pose challenges for

Nigel Jenkins

2007-01-01

222

A new numerical approach for uniquely solvable exterior Riemann-Hilbert problem on region with corners  

NASA Astrophysics Data System (ADS)

Numerical solution for uniquely solvable exterior Riemann-Hilbert problem on region with corners at offcorner points has been explored by discretizing the related integral equation using Picard iteration method without any modifications to the left-hand side (LHS) and right-hand side (RHS) of the integral equation. Numerical errors for all iterations are converge to the required solution. However, for certain problems, it gives lower accuracy. Hence, this paper presents a new numerical approach for the problem by treating the generalized Neumann kernel at LHS and the function at RHS of the integral equation. Due to the existence of the corner points, Gaussian quadrature is employed which avoids the corner points during numerical integration. Numerical example on a test region is presented to demonstrate the effectiveness of this formulation.

Zamzamir, Zamzana; Murid, Ali H. M.; Ismail, Munira

2014-06-01

223

On the Development of a Unique Arc Jet Test Apparatus for Control Surface Seal Evaluations  

NASA Technical Reports Server (NTRS)

NASA Glenn has developed a unique test apparatus capable of evaluating control surface seal and flap designs under simulated reentry heating conditions in NASA Johnson's arc jet test facility. The test apparatus is capable of testing a variety of seal designs with a variety of control surface materials and designs using modular components. The flap angle can be varied during testing, allowing modification of the seal environment while testing is in progress. The flap angle is varied using an innovative transmission system which limits heat transfer from the hot flap structure to the motor, all while keeping the components properly aligned regardless of thermal expansion. A combination of active and passive cooling is employed to prevent thermal damage to the test fixture while still obtaining the target seal temperature.

Finkbeiner, Joshua R.; Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Robbie, Malcolm; Baker, Gus; Erker, Arthur

2004-01-01

224

A unique elevated-temperature tension-torsion fatigue test rig  

NASA Astrophysics Data System (ADS)

A unique tension-torsion fatigue test set up is described that allows strain-controlled tests at temperatures exceeding 649 C. The machine uses a large die set as a load frame resulting in lower cost and superior parallel positioning of the crossheads. Disposable weld-on grips were found to be cost effective for elevated-temperature testing. A new extensometer using commercially available capacitance probes was developed which can operate at the elevated temperature without cooling. Capacitance ring probes were utilized in an attempt to measure through-thickness strains. The characteristic behavior of the ring probes is discussed. Design modifications needed to make a successful measurement of through-thickness strains at elevated temperatures are presented.

Jordan, E. H.; Chan, C. T.

1987-06-01

225

Modeling Exon Expression Using Histone Modifications  

PubMed Central

Histones undergo numerous covalent modifications that play important roles in regulating gene expression. Previous investigations have focused on the effects of histone modifications on gene promoters, whereas efforts to unravel their effects on transcribed regions have lagged behind. To elucidate the effects of histone modification on transcribed regions, we constructed a quantitative model, which we suggest can predict the variation of gene expression more faithfully than the model constructed on promoters. Moreover, motivated by the fact that exon spicing is functionally coupled to transcription, we also devised a quantitative model to predict alternative exon expression using histone modifications on exons. This model was found to be general across different exon types and even cell types. Furthermore, an interaction network linking histone modifications to alternative exon expression was constructed using partial correlations. The network indicated that gene expression and specific histone modifications (H3K36me3 and H4K20me1) could directly influence the exon expression, while other modifications could act in an additive way to account for the stability and robustness. In addition, our results suggest that combinations of histone modifications contribute to exon splicing in a redundant and cumulative fashion. To conclude, this study provides a better understanding of the effects of histone modifications on gene transcribed regions.

Zhu, Shijia; Wang, Guohua; Liu, Bo; Wang, Yadong

2013-01-01

226

A computer-controlled syringe driver for use during anaesthesia. A modification of the Graseby MS16A.  

PubMed

The requirements of a drug infusion device for use in theatre are discussed. A modification of the Graseby MS16A syringe pump and an interface circuit permitting its remote control by microcomputer are described. The pump is controlled via a standard computer interface (RS232) which makes it a unique and powerful research tool. Aspects of safety are considered. PMID:3707804

Cohen, A T

1986-06-01

227

Microfabrication, surface modification, and laser guidance techniques to create a neuron biochip  

Microsoft Academic Search

In this report we illustrate our application of soft lithography-based microfabrication, surface modification, and our unique\\u000a laser cell-patterning system toward the creation of neuron biochips. We deposited individual forebrain neurons from Day 7\\u000a embryonic chicks into two rows of eight in a silicon microstructure aligned over a microelectrode array (MEA). The polydimethylsiloxane\\u000a (PDMS) membrane with microstructures to confine cells and

Russell Kirk Pirlo; Xiang Peng; Xiaocong Yuan; Bruce Zhi Gao

2008-01-01

228

High-Throughput Liquid-Liquid Fractionation of Multiple Protein Post-Translational Modifications*  

PubMed Central

Post-translational protein modifications have contributed significantly to the identification of macromolecular biomarkers of biological processes. We have modified a 2-dimensional HPLC system (Beckman Coulter PF2D ProteomeLab) to create proteome maps of post-translational protein modifications. This system resolves complex protein mixtures by anion exchange chromatofocusing in the first dimension and hydrophobicity (reverse phase chromatography) in the second dimension. The simultaneous identification of multiple protein modifications, accomplished by incorporating a photo diode array (PDA) detector into the PF2D system, facilitates the simultaneous production of three dimensional proteome maps and visualization of both unmodified and post-translationally modified (PTM) proteins at their signature wavelengths within the proteome. We describe procedures for the simultaneous resolution of proteome maps, the identification of proteins modified by nitration, carbonylation, and phosphorylation, and proteins with unique spectra such as the heme containing proteins.

DeFord, James H.; Nuss, Jonathan E.; Amaning, James; English, Robert D.; Tjernlund, Don; Papaconstantinou, John

2009-01-01

229

Conformation effects of base modification on the anticodon stem-loop of Bacillus subtilis tRNA(Tyr).  

PubMed

tRNA molecules contain 93 chemically unique nucleotide base modifications that expand the chemical and biophysical diversity of RNA and contribute to the overall fitness of the cell. Nucleotide modifications of tRNA confer fidelity and efficiency to translation and are important in tRNA-dependent RNA-mediated regulatory processes. The three-dimensional structure of the anticodon is crucial to tRNA-mRNA specificity, and the diverse modifications of nucleotide bases in the anticodon region modulate this specificity. We have determined the solution structures and thermodynamic properties of Bacillus subtilis tRNA(Tyr) anticodon arms containing the natural base modifications N(6)-dimethylallyl adenine (i(6)A(37)) and pseudouridine (?(39)). UV melting and differential scanning calorimetry indicate that the modifications stabilize the stem and may enhance base stacking in the loop. The i(6)A(37) modification disrupts the hydrogen bond network of the unmodified anticodon loop including a C(32)-A(38)(+) base pair and an A(37)-U(33) base-base interaction. Although the i(6)A(37) modification increases the dynamic nature of the loop nucleotides, metal ion coordination reestablishes conformational homogeneity. Interestingly, the i(6)A(37) modification and Mg(2+) are sufficient to promote the U-turn fold of the anticodon loop of Escherichia coli tRNA(Phe), but these elements do not result in this signature feature of the anticodon loop in tRNA(Tyr). PMID:21782828

Denmon, Andria P; Wang, Jiachen; Nikonowicz, Edward P

2011-09-16

230

Upconversion Nanoparticles: Synthesis, Surface Modification, and Biological Applications  

PubMed Central

New generation fluorophores, also termed upconversion nanoparticles (UCNPs), have the ability to convert near infrared radiations with lower energy into visible radiations with higher energy via a non-linear optical process. Recently, these UCNPs have evolved as alternative fluorescent labels to traditional fluorophores, showing great potential for imaging and biodetection assays in both in vitro and in vivo applications. UCNPs exhibit unique luminescent properties, including high penetration depth into tissues, low background signals, large Stokes shifts, sharp emission bands, and high resistance to photo-bleaching, making UCNPs an attractive alternative source for overcoming current limitations in traditional fluorescent probes. In this review, we discuss the recent progress in the synthesis and surface modification of rare earth doped UCNPs with a specific focus on their biological applications.

Wang, Meng; Abbineni, Gopal; Clevenger, April; Mao, Chuanbin; Xu, Shukun

2011-01-01

231

Using the Modification Index and Standardized Expected Parameter Change for Model Modification  

ERIC Educational Resources Information Center

Model modification is oftentimes conducted after discovering a badly fitting structural equation model. During the modification process, the modification index (MI) and the standardized expected parameter change (SEPC) are 2 statistics that may be used to aid in the selection of parameters to add to a model to improve the fit. The purpose of this…

Whittaker, Tiffany A.

2012-01-01

232

Total Quality Management: A Unique Challenge For Behavioral Science Researchers.  

National Technical Information Service (NTIS)

This essay examines the unique new opportunities for behavioral scientists to develop innovative study methods which can be used to systematically collect data to create and support the implementation of Total Quality Management (TQM) programs in industry...

J.L. Mitchell J.R Knight

1992-01-01

233

New Guidelines for Reducing Stroke Risks Unique to Women  

MedlinePLUS

New guidelines for reducing stroke risks unique to women American Heart Association/American Stroke Association Scientific Statement ... Bushnell, M.D., M.H.S., author of the new scientific statement published in the American Heart Association ...

234

A NOTE ON UNIQUENESS IN THERMOELASTICITY WITH ONE RELAXATION TIME  

Microsoft Academic Search

Uniqueness for a general initial boundary-value problem of linear dynamic thermoelasticity with one relaxation time is established using the associated conservation law involving higher-order time derivatives.

Józef Ignaczak

1982-01-01

235

Automatic Test Systems: Unique vs. Common-Core Management.  

National Technical Information Service (NTIS)

Historically, individual system program offices developed and replaced unique automatic test systems (ATS) to support single weapon systems. However, significant increases in deployment footprints, parts obsolescence, and greater sustainment challenges le...

A. W. Johnson J. Bell J. Howe W. Ford

2007-01-01

236

The unique radar properties of silicic lava domes  

NASA Technical Reports Server (NTRS)

Silicic lava domes exhibit distinct morphologic characteristics at scales of centimeters to kilometers. Multiparameter radar observations capture the unique geometric signatures of silicic domes in a set of radar scattering properties that are unlike any other natural geologic surfaces.

Plaunt, J J.; Anderson, S. W.; Crown, D. A.; Stofan, E. R.; van Zyl, J. J.

2004-01-01

237

Unique Design of Doublet and Big Dee Vacuum Vessels.  

National Technical Information Service (NTIS)

The Doublet III tokamak now in its fourth year of operation at General Atomic Company, has its plasma contained in a kidney-shaped toroidal vacuum vessel, a configuration that presented unique design challenges. Most tokamak vacuum vessels are constructed...

J. E. Miller

1981-01-01

238

Atlantic Coast Unique Regional Atmospheric Tracer Experiment (ACURATE).  

National Technical Information Service (NTIS)

The Atlantic Coast Unique Regional Atmospheric Tracer Experiment (ACURATE) is a program designed to obtain data necessary to evaluate atmospheric transport and diffusion models used to calculate regional population doses caused by nuclear facility emissio...

J. F. Schubert J. L. Heffter G. A. Mead

1983-01-01

239

Contextual values as a foundation for a unique Weak Value  

NASA Astrophysics Data System (ADS)

We expand on the contextual values formalism introduced in Dressel et al., Phys. Rev. Lett. 104, 240401 (2010) and describe in detail the sufficient conditions for uniquely defining the generalized weak value as the weak limit of a conditioned average. We also respond to Parrott's proposed counter-example to the uniqueness of the generalization of the weak value [arXiv:1105.4188]. The counter-example does not satisfy our prescription in the case of an underdetermined measurement context. We show that when the contextual values formalism is properly applied to this example, a natural interpretation of the measurement emerges and the uniqueness result in the weak limit holds. A proof of the uniqueness result is given in the general case. We discuss several applications of the formalism.

Dressel, J.; Jordan, A. N.

2011-11-01

240

Behavior Modification: A Perspective on Critical Issues  

ERIC Educational Resources Information Center

Provides an overview of the current methods of behavior modification, reviews some critical issues, such as fear of control, use of aversive control, and behavior modification in prisons, in an effort to aid in differentiating warranted from unwarranted concerns. Ethical standards and practices are discussed. (Author/AM)

Stolz, Stephanie B.; And Others

1975-01-01

241

Size Adjectives and Adnominal Degree Modification  

Microsoft Academic Search

In languages that have them, adjectives and the functional structure they project are the prototypical means by which gradable notions are expressed, and consequently probably the clearest window available onto how degree modification works. But degree modification occurs outside the adjectival domain as well (a fact noted by Bolinger 1972, Abney 1987, Deutjes 1997, Kennedy and McNally 2004 among oth-

Marcin Morzycki

242

The Modification of Compounds by Attributive Adjectives  

ERIC Educational Resources Information Center

This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun…

Berg, Thomas

2011-01-01

243

Surface Modification of Clays and Related Materials  

Microsoft Academic Search

This review analyzes various ways by which the surfaces of clay particles and related minerals can be non?covalently modified, as well as some of the analytical approaches with which these surface modifications can be measured and quantified. Among the principal methods of modification of the surface properties of clays and other metal oxide surfaces is treatment with cationic surfactants comprising

C. J. van Oss; R. F. Giese

2003-01-01

244

Quality planning for major plant design modifications  

SciTech Connect

This paper reviews the approach and activities undertaken by Public Service Electric and Gas Company's (PSE and G's) nuclear quality assurance (QA) department to support major plant design modifications conducted during refueling outages at Salem Generating Station. It includes the planning and implementation of quality plans developed to provide both QA and quality control (QC) coverage of modification performed by contracted service organizations.

Dulee, R.J.

1988-01-01

245

UAE Teachers' Awareness & Perceptions of Testing Modifications  

ERIC Educational Resources Information Center

The objectives of this study were threefold: (a) to determine whether the United Arab Emirates (UAE) general and special education teachers were making any specific testing modifications for students with disabilities; (b) to survey UAE general and special education teachers' perceptions of testing modifications in terms of their usefulness,…

Elhoweris, Hala; Alsheikh, Negmeldin

2010-01-01

246

Modification of integrated partial payload lifting assembly  

NASA Technical Reports Server (NTRS)

The Integrated Partial Payload Lifting Assembly (IPPLA) is currently used to transport and load experimental payloads into the cargo bay of the Space Shuttle. It is unable to carry the astronaut/passenger tunnel without a structural modification. The purpose of this design is to create a removalbe modification that will allow the IPPLA to lift and carry the passenger tunnel. Modifications evaluated were full-length insert beams which would extend through the existing strongback arms. These beam proposals were eliminated because of high cost and weight. Other proposals evaluated were attachments of cantilever beams to the existing strongback areas. The cantilever proposals reduced cost and weight compared to the full-length modifications. A third method evaluated was to simply make modifications to one side of the IPPLA therefore reducing the materials of the cantilever proposals by 40 percent. The design of the modification selected was completed with two channel beams jointly welded to a centered steel plate. The extension arm modification is inserted into the existing strongback channel beams and bolted into place. Two extension arms are added to one side of the IPPLA to provide the extra length needed to accommodate the passenger tunnel. The center counterbalance will then be offset about 20 inches to center gravity and therefore maintain horizontal status. The extension arm modification was selected because of minimum cost, low weight, and minimal installation time.

Groah, Melodie; Haddock, Michael; Woodworth, Warren

1986-01-01

247

Behavior Modification: Perspective on a Current Issue.  

ERIC Educational Resources Information Center

Presented is an overview of the history and current methods and a review of some critical issues related to behavior modification. Behavior modification is defined, and examples of methods such as positive reinforcement, aversive control, and systematic desensitization are provided. Summarized are evaluations of the effectiveness of behavior…

Brown, Bertram S.; And Others

248

Windowless argon excimer source for surface modification  

Microsoft Academic Search

The article describes applications of a novel windowless argon excimer source for surface modification. Experimental results on etching of polymeric surfaces, degradation of organic surface residues, surface activation and modification of gas permeability and selectivity of polymeric membranes are presented. Moreover, radical formation from the excimer source and surface curing of liquid acrylates are examined. Typical treatment times are in

Christian Elsner; Martin Lenk; Lutz Prager; Reiner Mehnert

2006-01-01

249

Regulation of chromatin by histone modifications  

Microsoft Academic Search

Chromatin is not an inert structure, but rather an instructive DNA scaffold that can respond to external cues to regulate the many uses of DNA. A principle component of chromatin that plays a key role in this regulation is the modification of histones. There is an ever-growing list of these modifications and the complexity of their action is only just

Andrew J Bannister; Tony Kouzarides

2011-01-01

250

A novel DNA modification by sulphur  

Microsoft Academic Search

Summary Streptomyces lividans has a novel DNA modification, which sensitises its DNA to degradation during elec- trophoresis (the Dnd phenotype). The entire gene cluster ( dnd ) involved in this modification was local- ized on an 8 kb DNA fragment and was expressed in a S. lividans deletion mutant ( dnd ) and in several heterologous hosts. Disruption of the

Xiufen Zhou; Xinyi He; Jingdan Liang; Aiying Li; Tiegang Xu; Tobias Kieser; John D. Helmann

251

Prevention of biofilm formation by polymer modification  

Microsoft Academic Search

Bacterial biofilm formation on synthetic polymers plays an important role in industry and in modern medicine, leading, for example, to difficult-to-treat infections caused by colonized foreign bodies. Prevention of biofilm formation is a necessary step in the successful prophylaxis of such infections. One approach is to inhibit bacterial adherence by polymer surface modification. We have investigated polymer modification by glow

B Jansen; W Kohnen

1995-01-01

252

Accidental and planned weather modification in illinois  

Microsoft Academic Search

Weather modification, both planned by humans and accidentally produced by humans, is the focus of an Illinois study. Populations in Illinois and the Midwest are living in a climate that is now modified inadvertently from its natural state. State atmospheric scientists have tackled weather modification through a series of interrelated studies, experimental design studies, experimental field studies to verify changes

1977-01-01

253

unexceptional.net A Story about a Unique Pervasive Game  

Microsoft Academic Search

This paper describes the pervasive game unexceptional.net. Unexceptional.net is a unique pervasive game that is story-driven where the story evolves through multiple media channels interacting with the player. The game interacts with the user on a cellphone and a PC, and the game provides unique gaming experience by introducing gameplay elements through comics, web hacks, Blogs, a 3D-client, a database

Robert F. Nideffer; Alf Inge Wang

254

A Uniqueness Theorem for Stationary Kaluza-Klein Black Holes  

NASA Astrophysics Data System (ADS)

We prove a uniqueness theorem for stationary D-dimensional Kaluza-Klein black holes with D - 2 Killing fields, generating the symmetry group {{mathbb R}× U(1)^{D-3}}. It is shown that the topology and metric of such black holes is uniquely determined by the angular momenta and certain other invariants consisting of a number of real moduli, as well as integer vectors subject to certain constraints.

Hollands, Stefan; Yazadjiev, Stoytcho

2011-03-01

255

On uniqueness for anisotropic inhomogeneous inverse scattering problems  

Microsoft Academic Search

The problem of determining the shape of a two-dimensional inhomogeneous orthotropic scatterer from far-field data is considered. In particular, by using integral equation techniques we prove that the support of the scatterer is uniquely determined if the far-field pattern is known for all incident directions. We point out that this uniqueness result may be useful also for practical applications, since

M. Piana

1998-01-01

256

Dynamics of Femtosecond Laser Modification Inside Fused Silica  

NASA Astrophysics Data System (ADS)

Femtosecond (fs) laser modification of transparent media provides great potential for the creation of a wide variety of novel optical devices. Progress in the creation of many devices has been limited by a lack of understanding of the mechanism behind the fs-laser modification process. To better understand the nature and behavior of fs-laser modification inside a transparent medium both the short and long time-scale dynamics of the modification process in fused silica were investigated in this thesis research. To measure short time-scale dynamics of the fs-laser generated plasma inside fused silica a novel, broadband fs pump-probe experiment was built with the broadband probe ranging from 500--1100 nm. In this setup a strongly focused, 800 nm, fs pump pulse is used to create a plasma, which is subsequently interrogated by the weak broadband probe. The time delay between pump and probe can be varied over a 1 ns range with a time resolution of 440 fs. Probe transmission measurements show that, as the energy of the modifying fs-laser pulse increases, the electron density remains capped at 4.0x10 21 cm-3, which is roughly the critical density associated with the pump wavelength of 800 nm, while the plasma size increases. The spectral shape of the probe transmission suggests that the plasmas generated in the experiments are "collisionless" with electron collision times > 500 fs. The experimental plasmas persist for longer than ˜1 ns after absorption of the fs-laser pulse. Plasma structure and emission characteristics depend on the pulse energy of the modifying fs-laser. At high pulse energies the structure within the plasma exhibits poor stability with very inhomogeneous emission characteristics. At lower pulse energies the fs-laser generated plasmas exhibit a stable "head and tail" structure with two distinct regions of emission: an intense, broad emission centered at 540 nm ("head" region) and a weaker, narrower emission centered at 475 nm ("tail" region). Long time-scale dynamics were studied by observing changes to fs-laser modified structures under various thermal annealing conditions. Using confocal fluorescence and Raman microscopy, changes in fs-laser induced non-bridging oxygen hole center (NBOHC) defects were monitored through their fluorescence at 650 nm, while changes in the glass network, specifically the concentration of 3-membered Si-O rings, were measured by the relative intensity of the 605 cm-1 Raman peak. NBOHC defects and the Si-O ring distributions of fs-laser modified structures return to levels of unmodified fused silica through thermal annealing. In both cases the required annealing temperatures are far below the glass transition temperature: 300 °C for NBOHCs and 900 °C for 3-membered Si-O rings. The disappearance of these defect and glass network changes is not always accompanied by the removal of the visible modification created by the fs-laser absorption. Under fs-laser conditions that produce "smooth" refractive index changes, suitable for optical waveguide writing, the visible structures return to that of the bulk glass. Under fs-laser conditions that result in visibly "rough" modification that includes cracks and exhibits strong scattering, the visible structure remains constant for annealing temperatures up to 900 °C even when the NBOHC and Si-O ring concentrations return to unmodified values. The design of the unique broadband pump-probe experiment allows for new, robust measurements of short time-scale plasma dynamics. Such short time-scale dynamics along with measurements of long time-scale dynamics and stability of the fs-laser induced modification improve the understanding of the fs-laser modification process.

Witcher, Jonathan Jetty

257

Bioactive Surface Modification of Hydroxyapatite  

PubMed Central

The purpose of this study was to establish an acid-etching procedure for altering the Ca/P ratio of the nanostructured surface of hydroxyapatite (HAP) by using surface chemical and morphological analyses (XPS, XRD, SEM, surface roughness, and wettability) and to evaluate the in vitro response of osteoblast-like cells (MC3T3-E1 cells) to the modified surfaces. This study utilized HAP and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid solution for 10 minutes at 25°C, followed by rinsing 3 times with ultrapure water. The 30% phosphoric acid etching process that provided a Ca/P ratio of 1.50, without destruction of the grain boundary of HAP, was selected as a surface-modification procedure. Additionally, HAP treated by the 30% phosphoric acid etching process was stored under dry conditions at 25°C for 12 hours, and the Ca/P ratio approximated to 1.00 accidentally. The initial adhesion, proliferation, and differentiation (alkaline phosphatase (ALP) activity and relative mRNA level for ALP) of MC3T3-E1 cells on the modified surfaces were significantly promoted (P < 0.05 and 0.01). These findings show that the 30% phosphoric acid etching process for the nanostructured HAP surface can alter the Ca/P ratio effectively and may accelerate the initial adhesion, proliferation, and differentiation of MC3T3-E1 cells.

Okazaki, Yohei; Hiasa, Kyou; Yasuda, Keisuke; Nogami, Keisuke; Mizumachi, Wataru; Hirata, Isao

2013-01-01

258

Enzymatic modification of flaxseed fibers.  

PubMed

Flaxseed (Linum usitatissimum L.) fibers were modified by oxidoreductive and cellulolytic enzymes. The lignin amount and intrinsic plant peroxidase activity was evaluated by histochemical and spectrophotometric assays. Peroxidase activity was not found from bast fibers. The flaxseed fibers were further separated and treated with laccase to conjugate the model compounds, that is, the hydrophobic gallate molecules on fiber surfaces. Laccase was able to slowly oxidize fiber-conjugated phenolics, but no fundamental changes in fiber cell surface structure or notable coupling of the applied hydrophobic gallate molecules onto the fibers occurred, as revealed by Fourier transform infrared spectroscopy. The reactivity of the mature fibers was further investigated using cellulolytic enzymes. Cellobiohydrolase (CBH) and endoglucanase (EG)-rich enzyme preparations were applied to reach a hydrolysis degree of 1-6% (of the fiber dry matter) using a standard enzyme dosage. The CBH mixture altered the fiber surface morphology distinctly, and SEM images illustrated fibers in which the cellulose fibrils seemed to be loosened and partially hydrolyzed. In contrast, the effect of the EG-rich preparation without CBH activity was notable on the fiber surface, polishing the surfaces. The cellulolytic treatments were potentially interesting for specific enzymatic modifications of flax fiber surfaces, whereas the approach to use oxidoreductive enzyme treatments on mature linseed fibers offered little potential, obviously due to the low lignin content of the fibers. PMID:23098092

Maijala, Pekka; Mäkinen, Marliina; Galkin, Sari; Fagerstedt, Kurt; Härkäsalmi, Tiina; Viikari, Liisa

2012-11-01

259

Infections associated with body modification.  

PubMed

Although exact statistics are lacking, body modifications for cosmetic purposes are performed in many countries. The commonest forms include tattooing, body piercing, and breast and facial augmentation using implants or injectable fillers. Liposuction and, to a lesser extent, mesotherapy are also practiced in many countries. Infective complications of these procedures include local infections, transmission of bloodborne pathogens (viral hepatitis and human immunodeficiency virus), and distant infections such as infective endocarditis. Presence of foreign bodies, long healing time of piercing wounds, and poor compliance with infection control practices of some practitioners all predispose the recipients to infections. Apart from the endogenous microbial flora of the skin and mucosae, atypical mycobacteria, especially the rapid growers, have emerged as some of the most important pathogens in such settings. Outbreaks of infection are commonly reported. We hereby review the current knowledge of the topic with specific focus on infections associated with tattooing, body piercing, breast augmentation, mesotherapy, liposuction, and tissue filler injections. Greater awareness among consumers and health-care professionals, as well as more stringent regulations by the health authorities, is essential to minimize the health risks arising from these procedures. PMID:23265745

Wong, Samson Sai-Yin; Wong, Sally Cheuk-Ying; Yuen, Kwok-Yung

2012-12-01

260

Effect modification by time-varying covariates.  

PubMed

Marginal structural models (MSMs) allow estimation of effect modification by baseline covariates, but they are less useful for estimating effect modification by evolving time-varying covariates. Rather, structural nested models (SNMs) were specifically designed to estimate effect modification by time-varying covariates. In their paper, Petersen et al. (Am J Epidemiol 2007;166:985-993) describe history-adjusted MSMs as a generalized form of MSM and argue that history-adjusted MSMs allow a researcher to easily estimate effect modification by time-varying covariates. However, history-adjusted MSMs can result in logically incompatible parameter estimates and hence in contradictory substantive conclusions. Here the authors propose a more restrictive definition of history-adjusted MSMs than the one provided by Petersen et al. and compare the advantages and disadvantages of using history-adjusted MSMs, as opposed to SNMs, to examine effect modification by time-dependent covariates. PMID:17875581

Robins, James M; Hernán, Miguel A; Rotnitzky, Andrea

2007-11-01

261

Identification of unique food handling practices that could represent food safety risks for minority consumers.  

PubMed

Foodborne illness caused by Salmonella and Campylobacter is a concern for consumers, and there is evidence that minority racial-ethnic populations experience greater rates of illness because of these pathogens. The limited body of research concerning food safety knowledge and practices among minority consumers has focused more on general food safety knowledge than on culturally specific food handling practices. The purpose of the research reported here was to explore food handling behaviors of minority racial-ethnic consumers through in-depth discussions in focus group settings. In this way, we hoped to identify potential unique, previously unidentified food handling practices among these consumers. Nine focus groups were held in Philadelphia, PA. Three focus groups were conducted with African American consumers, three with Hispanic consumers, and three with Asian consumers. In all, 56 consumers participated. Data were recorded, transcribed, and analyzed for unique and potentially unsafe food handling behaviors. Potentially unsafe food handling practices identified among all three groups included extended time to transport food from retail to home and washing of raw poultry. Culturally unique behaviors within groups included (i) using hot water (Asian, Hispanic) or acidic solutions (African American, Hispanic) to clean raw poultry, (ii) purchasing live poultry (Asian, Hispanic), (iii) cooking poultry overnight (African American), and (iv) preparing bite-size pieces of meat prior to cooking (Asian, Hispanic). To have focus groups include a limited number of participants and nonrandom sampling means that these themes and trends cannot be extrapolated to represent food mishandling among these populations in general. Results presented here allow modification of an existing food safety survey to identify the prevalence of these food handling practices among consumers of different demographics. PMID:23127716

Henley, Shauna C; Stein, Susan E; Quinlan, Jennifer J

2012-11-01

262

Surface modification of a microcellular porous solid: carbon foam  

NASA Astrophysics Data System (ADS)

Microcellular solids such as carbon foams offer unique advantages over traditional solids in many applications. However, since these structures are 80-90% porous, they have a high interface/volume ratio, and surface driven properties such as atmospheric tolerance and bond formation with the matrix material are crucial for applicability. This calls for controlled surface modification techniques that can tailor surface-related properties without compromising the desirable bulk properties of the material (graphite in this case). Several types of modification, using liquid-phase and plasma-phase treatments, have been investigated by this group. One of the goals is to improve composite formation. If a composite is to be made with the foam, it needs to be infiltrated with a matrix phase (e.g. epoxy for structural composite or metal for thermal composite). Enhanced infiltration of the matrix material and optimum bond-strength is achieved by surface treatments that increase chemical affinity between the two phases. Hydrophilic coatings that increase oxygen-functional groups on the surface are seen to be very effective. The second modification goal is to enhance the foam's durability as a stand-alone solid (such as in a lightweight sandwich structure or thermal dissipation foam). Coatings that incorporate moisture-repellent and chemically inert groups (such as fluorocarbons) achieve this. The following aspects of these coatings have been discussed: (a) chemistry of specific surface functional groups, (b) contact angle changes with water, and (c) infiltration of water (which is a predictor of infiltration of other polar compounds). The significance of these results to our understanding of composite interfaces and future fabrication issues has been discussed.

Mukhopadhyay, S. M.; Pulikollu, R. V.; Roy, A. K.

2004-03-01

263

Unique genes in plants: specificities and conserved features throughout evolution  

PubMed Central

Background Plant genomes contain a high proportion of duplicated genes as a result of numerous whole, segmental and local duplications. These duplications lead up to the formation of gene families, which are the usual material for many evolutionary studies. However, all characterized genomes include single-copy (unique) genes that have not received much attention. Unlike gene duplication, gene loss is not an unspecific mechanism but is rather influenced by a functional selection. In this context, we have established and used stringent criteria in order to identify suitable sets of unique genes present in plant proteomes. Comparisons of unique genes in the green phylum were used to characterize the gene and protein features exhibited by both conserved and species-specific unique genes. Results We identified the unique genes within both A. thaliana and O. sativa genomes and classified them according to the number of homologs in the alternative species: none (U{1:0}), one (U{1:1}) or several (U{1:m}). Regardless of the species, all the genes in these groups present some conserved characteristics, such as small average protein size and abnormal intron number. In order to understand the origin and function of unique genes, we further characterized the U{1:1} gene pairs. The possible involvement of sequence convergence in the creation of U{1:1} pairs was discarded due to the frequent conservation of intron positions. Furthermore, an orthology relationship between the two members of each U{1:1} pair was strongly supported by a high conservation in the protein sizes and transcription levels. Within the promoter of the unique conserved genes, we found a number of TATA and TELO boxes that specifically differed from their mean number in the whole genome. Many unique genes have been conserved as unique through evolution from the green alga Ostreococcus lucimarinus to higher plants. Plant unique genes may also have homologs in bacteria and we showed a link between the targeting towards plastids of proteins encoded by plant nuclear unique genes and their homology with a bacterial protein. Conclusion Many of the A. thaliana and O. sativa unique genes are conserved in plants for which the ancestor diverged at least 725 million years ago (MYA). Half of these genes are also present in other eukaryotic and/or prokaryotic species. Thus, our results indicate that (i) a strong negative selection pressure has conserved a number of genes as unique in genomes throughout evolution, (ii) most unique genes are subjected to a low divergence rate, (iii) they have some features observed in housekeeping genes but for most of them there is no functional annotation and (iv) they may have an ancient origin involving a possible gene transfer from ancestral chloroplasts or bacteria to the plant nucleus.

2008-01-01

264

Orographic Modification of Cyclone Development.  

NASA Astrophysics Data System (ADS)

The orographic modification of cyclone development is examined by means of primitive equation model simulations. When a mature baroclinic wave impinges on an east-west oriented mountain ridge, a relatively intense cyclone forms on the south side of the ridge. This cyclone extends throughout the depth of the troposphere and possesses relatively small vertical tilts, large velocities, and strong temperature perturbations compared to classical baroclinic eddies. The vorticity growth in the orographic cyclone center is larger than that of baroclinic eddies that grow over flat terrain. However, there is no absolute instability associated with this orographic enhancement. A longer ridge produces a more intense eddy.The behavior of small-amplitude normal modes on a zonally symmetric mountain ridge shows that baroclinic development is enhanced where the topography slopes in the same direction as the isentropes. This is consistent with earlier studies using uniform slopes that show that the heat flux forced by this terrain enhances the conversion of available potential energy. It is shown that the structure of nonlinear waves is similar to that of linear modes over a mountain ridge with steep slopes, in which the cross-ridge flow and the associated heat flux are partially blocked by the mountain.Simulations of a stationary cold front interacting with a mountain ridge suggest that orographic cyclogenesis is triggered when the mountain ridge locally modifies the frontal circulation as it impinges on the ridge. Warm southerly flow in the front is diverted westward by the mountain ridge, intensifying the strong hydrostatic pressure gradient between the mountain anticyclone and the developing cyclone to the south. In contrast, cold northerly flow is diverted eastward as it approaches the mountain and effectively broadens the mountain anticyclone toward the north. This produces the characteristic pressure dipole observed in orographic cyclogenesis. It is concluded that mature baroclinic eddies approaching the mountain ridge should have a strong frontal zone with a considerable temperature contrast and strong circulation for an intense response.

Orlanski, Isidoro; Gross, Brian D.

1994-02-01

265

Ion beam modification of metals  

NASA Astrophysics Data System (ADS)

Energetic ions beams may be used in various ways to modify and so improve the tribological properties of metals. These methods include: — ion implantation of selected additive species; — ion beam mixing of thin deposited coatings; — ion-beam-assisted deposition of thicker overlay coatings. The first of these techniques has been widely used to modify the electronic properties of semiconductors, but has since been extended for the treatment of all classes of material. Tool steels can be strengthened by the ion implantation of nitrogen or titanium, to produce fine dispersions of hard second-phase precipitates. Solid solution strengthening, by combinations of substitutional and interstitial species, such as yttrium and nitrogen, has also been successful. Both ion beam mixing (IBM) and ion-beam-assisted deposition (IBAD) use a combination of coating and ion bombardment. In the first case, the objective is to intermix the coating and substrate by the aid of radiation-enhanced diffusion. In the latter case, the coating is densified and modified during deposition and the process can be continued in order to build up overlay coatings several ?m in thickness. The surface can then be tailored, for instance to provide a hard and adherent ceramic such as silicon nitride, boron nitride or titanium nitride. It is an advantage that all the above processes can be applied at relatively low temperatures, below about 200° C, thereby avoiding distortion of precision components. Ion implantation is also being successfully applied for the reduction of corrosion, especially at high temperatures or in the atmosphere and to explore the mechanisms of oxidation. Ion-assisted coatings, being compact and adherent, provide a more substantial protection against corrosion: silicon nitride and boron nitride are potentially useful in this respect. Examples will be given of the successful application of these methods for the surface modification of metals and alloys, and developments in the equipment now available for industrial application of ion beams will also be reviewed.

Dearnaley, G.

1990-04-01

266

Modification of Sr on 4004 Aluminum Alloy  

NASA Astrophysics Data System (ADS)

As a brazing foil, 4004 Al alloy has good welding performance. However, the high Si content decreases the plasticity of the alloy. To improve the plasticity of 4004 Al alloy and subsequently improve the productivity of 4004 Al foil or 434 composite foil, 4004 Al alloy was modified by Al-10%Sr master alloy. Modification effects of an additional amount of Sr, modification temperature, and holding time on 4004 aluminum alloy were studied by orthogonal design. The results showed that the greatest impact parameter of 4004 aluminum alloy modification was the additional amount of Sr, followed by holding time and modification temperature. The optimum modification parameters obtained by orthogonal design were as follows: Sr addition of 0.04%, holding time of 60 min, and modification temperature of 760°C. The effect of Sr addition on modification was analyzed in detail based on orthogonal results. With increasing of Sr addition, elongation of 4004 alloy increased at first, and decreased after reaching the maximum value.

Guo, Erjun; Cao, Guojian; Feng, Yicheng; Wang, Liping; Wang, Guojun; Lv, Xinyu

2013-05-01

267

Evolutionary conservation of histone modifications in mammals.  

PubMed

Histone modification is an important mechanism of gene regulation in eukaryotes. Why many histone modifications can be stably maintained in the midst of genetic and environmental changes is a fundamental question in evolutionary biology. We obtained genome-wide profiles of three histone marks, H3 lysine 4 tri-methylation (H3K4me3), H3 lysine 4 mono-methylation (H3K4me1), and H3 lysine 27 acetylation (H3K27ac), for several cell types from human and mouse. We identified histone modifications that were stable among different cell types in human and histone modifications that were evolutionarily conserved between mouse and human in the same cell type. We found that histone modifications that were stable among cell types were also likely to be conserved between species. This trend was consistently observed in promoter, intronic, and intergenic regions for all of the histone marks tested. Importantly, the trend was observed regardless of the expression breadth of the nearby gene, indicating that slow evolution of housekeeping genes was not the major reason for the correlation. These regions showed distinct genetic and epigenetic properties, such as clustered transcription factor binding sites (TFBSs), high GC content, and CTCF binding at flanking sides. Based on our observations, we proposed that TFBS clustering in or near a histone modification plays a significant role in stabilizing and conserving the histone modification because TFBS clustering promotes TFBS conservation, which in turn promotes histone modification conservation. In summary, the results of this study support the view that in mammalian genomes a common mechanism maintains histone modifications against both genetic and environmental (cellular) changes. PMID:22319170

Woo, Yong H; Li, Wen-Hsiung

2012-07-01

268

On the uniqueness of Kerr-Newman black holes  

NASA Astrophysics Data System (ADS)

The uniqueness of the Kerr-Newman family of black hole metrics as stationary asymptotically flat solutions to the Einstein equations coupled to a free Maxwell field is a crucial ingredient in the study of final states of the universe in general relativity. If one imposes the additional requirement that the space-time is axial-symmetric, then said uniqueness was shown by the works of B. Carter, D.C. Robinson, G.L. Bunting, and P.O. Mazur during the 1970s and 80s. In the real-analytic category, the condition of axial symmetry can be removed through S. Hawking's Rigidity Theorem. The necessary construction used in Hawking's proof, however, breaks down in the smooth category as it requires solving an ill-posed hyperbolic partial differential equation. The uniqueness problem of Kerr-Newman metrics in the smooth category is considered here following the program initiated by A. Ionescu and S. Klainerman for uniqueness of the Kerr metrics among solutions to the Einstein vacuum equations. In this work, a space-time, tensorial characterization of the Kerr-Newman solutions is obtained, generalizing an earlier work of M. Mars. The characterization tensors are shown to obey hyperbolic partial differential equations. Using the general Carleman inequality of Ionescu and Klainerman, the uniqueness of Kerr-Newman metrics is proven, conditional on a rigidity assumption on the bifurcate event horizon.

Wong, Willie Wai-Yeung

269

TRP channel activation by reversible covalent modification.  

PubMed

Allyl isothiocyanate, the pungent principle of wasabi and other mustard oils, produces pain by activating TRPA1, an excitatory ion channel on sensory nerve endings. Isothiocyanates are membrane-permeable electrophiles that form adducts with thiols and primary amines, suggesting that covalent modification, rather than classical lock-and-key binding, accounts for their agonist properties. Indeed, we show that thiol reactive compounds of diverse structure activate TRPA1 in a manner that relies on covalent modification of cysteine residues within the cytoplasmic N terminus of the channel. These findings suggest an unusual paradigm whereby natural products activate a receptor through direct, reversible, and covalent protein modification. PMID:17164327

Hinman, Andrew; Chuang, Huai-Hu; Bautista, Diana M; Julius, David

2006-12-19

270

Characterization of Tyrosine Nitration and Cysteine Nitrosylation Modifications by Metastable Atom-Activation Dissociation Mass Spectrometry  

NASA Astrophysics Data System (ADS)

The fragmentation behavior of nitrated and S-nitrosylated peptides were studied using collision induced dissociation (CID) and metastable atom-activated dissociation mass spectrometry (MAD-MS). Various charge states, such as 1+, 2+, 3+, 2-, of modified and unmodified peptides were exposed to a beam of high kinetic energy helium (He) metastable atoms resulting in extensive backbone fragmentation with significant retention of the post-translation modifications (PTMs). Whereas the high electron affinity of the nitrotyrosine moiety quenches radical chemistry and fragmentation in electron capture dissociation (ECD) and electron transfer dissociation (ETD), MAD does produce numerous backbone cleavages in the vicinity of the modification. Fragment ions of nitrosylated cysteine modifications typically exhibit more abundant neutral losses than nitrated tyrosine modifications because of the extremely labile nature of the nitrosylated cysteine residues. However, compared with CID, MAD produced between 66% and 86% more fragment ions, which preserved the labile -NO modification. MAD was also able to differentiate I/L residues in the modified peptides. MAD is able to induce radical ion chemistry even in the presence of strong radical traps and therefore offers unique advantages to ECD, ETD, and CID for determination of PTMs such as nitrated and S-nitrosylated peptides.

Cook, Shannon L.; Jackson, Glen P.

2011-02-01

271

Properties of Statistical Equilibrium Equations: Positivity and Uniqueness  

NASA Astrophysics Data System (ADS)

While linear statistical equilibrium equations play an important role in the description of nonequilibrium processes in astrophysics, some of their basic mathematical properties, such as uniqueness and positivity, have not been fully explored. In this paper these properties are related to concepts of connectivity from the theory of continuous-time Markov chains. For the irreducible case (in which every state is connected to every other state, either directly or through intermediate states), the solution is shown to be positive and unique when one positive normalization condition is provided. It is then shown how a general linear statistical equilibrium problem can be reduced by dividing the system into inessential and essential states and then partitioning the latter into separate irreducible subproblems. It is shown that: (1) The inessential states all have zero populations. If a positive normalization condition is imposed separately on each irreducible subproblem, then (2) the essential states all have positive populations and (3) the overall solution is unique.

Rybicki, George B.

1997-04-01

272

47 CFR 73.875 - Modification of transmission systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Modification of transmission systems. 73.875 Section 73...LPFM) § 73.875 Modification of transmission systems. The following procedures...modifications of authorized broadcast transmission system facilities. (a) The...

2013-10-01

273

Dental misidentification on the basis of presumed unique features.  

PubMed

Positive identification of skeletal remains by dental comparison depends on the demonstrable concordance between postmortem and antemortem records. However, there is no accepted norm for the number of points of concordance and there are circumstances when a single (or a few) unique features may allow positive identification. We present a recent case in which superficial similarity may have led to misidentification. We argue that misidentification is particularly likely with over-reliance on apparently unique features. The fact that a single inexplicable inconsistency will rule out a positive dental identification is highlighted. PMID:11813499

Kieser, J A; Firth, N A; Buckley, H

2001-12-01

274

Symptomatic plantar fibroma with a unique sonographic appearance.  

PubMed

We present a case of a solitary plantar fibroma with unique sonographic features with MRI and pathologic correlation. A 25-year-old woman presented with a left foot mass that interfered with her gait. Sonography demonstrated a well-circumscribed, 32 mm × 27 mm × 14 mm subcutaneous mass with heterogeneous echogenicity. Unique sonographic characteristics included posterior acoustic enhancement, cystic components, and mild intratumoral hypervascularity. MRI confirmed the sonographic findings. Surgical excision was performed without complication. A pathologic diagnosis of fibroma with myxoid degeneration and cyst formation was made. PMID:21656782

Haun, Daniel W; Cho, John C S; Kettner, Norman W

2012-02-01

275

Cooling Tower Modification for Intermittent Operation.  

National Technical Information Service (NTIS)

One of the cooling towers at Los Alamos Scientific Laboratory is being operated intermittently. The cooling tower has been modified to restrict air flow and to keep the tower from drying out. The modifications are relatively inexpensive, simple to operate...

W. S. Midkiff

1975-01-01

276

Formal Design Review Foot Clamp Modification  

SciTech Connect

This report documents the Design Review performed for the foot clamp modification. The report documents the acceptability of the design, identifies the documents that were reviewed, the scope of the review and the members of the review team.

OTEN, T.C.

2000-01-24

277

40 CFR 60.14 - Modification.  

Code of Federal Regulations, 2010 CFR

...this section, any physical or operational...modification within the meaning of section...resulting from the physical or operational...three after the physical or operational change. All operating parameters which may...

2010-07-01

278

40 CFR 60.14 - Modification.  

Code of Federal Regulations, 2010 CFR

...this section, any physical or operational...modification within the meaning of section...resulting from the physical or operational...three after the physical or operational change. All operating parameters which...

2009-07-01

279

A-1 modification work under way  

NASA Technical Reports Server (NTRS)

Phil Schemanski of Pratt & Whitney Rocketdyne removes equipment inside the thrust drum on the A-1 Test Stand as part of a comprehensive modification project to prepare for testing the new J-2X engine.

2008-01-01

280

Post-Translational Modifications of TRP Channels  

PubMed Central

Transient receptor potential (TRP) channels constitute an ancient family of cation channels that have been found in many eukaryotic organisms from yeast to human. TRP channels exert a multitude of physiological functions ranging from Ca2+ homeostasis in the kidney to pain reception and vision. These channels are activated by a wide range of stimuli and undergo covalent post-translational modifications that affect and modulate their subcellular targeting, their biophysical properties, or channel gating. These modifications include N-linked glycosylation, protein phosphorylation, and covalent attachment of chemicals that reversibly bind to specific cysteine residues. The latter modification represents an unusual activation mechanism of ligand-gated ion channels that is in contrast to the lock-and-key paradigm of receptor activation by its agonists. In this review, we summarize the post-translational modifications identified on TRP channels and, when available, explain their physiological role.

Voolstra, Olaf; Huber, Armin

2014-01-01

281

Sustainable environmental nanotechnology using nanoparticle surface modification.  

EPA Science Inventory

Reactive nanomaterials used for environmental remediation require surface modification to make them mobile in the subsurface. Nanomaterials released into the environment inadvertently without an engineered surface coating will acquire one (e.g. adsorption of natural organic matt...

282

Oxidative Modifications of Mitochondria Complex II  

PubMed Central

Summary Increased superoxide (O2•?) and nitric oxide (NO) production is a key mechanism of mitochondrial dysfunction in myocardial ischemia/reperfusion injury. In the complex II, oxidative impairment, decreased protein S-glutathionylation, and increased protein tyrosine nitration at the 70 kDa subunit occurs in the post-ischemic myocardium (1–3). To gain the deeper insights into ROS–mediated oxidative modifications relevant in myocardial infarction, isolated complex II is subjected to in vitro oxidative modifications with GSSG (to induce cystine S-glutathionylation) or OONO? (to induce tyrosine nitration). Here, we describe the protocol to characterize the specific oxidative modifications at the 70 kDa subunit by nano-LC/MS/MS analysis. We further demonstrate the cellular oxidative modification with protein nitration/S-glutathionylation with immunofluorescence microscopy using the antibodies against 3-nitrotyrosine/glutathione and complex II 70 kDa polypeptide (AbGSC90) in myocytes under conditions of oxidative stress.

Zhang, Liwen; Kang, Patrick T.; Chen, Chwen-Lih; Green-Church, Kari B.; Chen, Yeong-Renn

2013-01-01

283

38 CFR 36.4315 - Loan modifications.  

Code of Federal Regulations, 2013 CFR

...Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) LOAN GUARANTY Guaranty or Insurance of Loans to Veterans With Electronic Reporting § 36.4315 Loan modifications...best interests of the veteran and the Government after balancing the risks of...

2013-07-01

284

Telephone Channel Monitor System Modification and Evaluation.  

National Technical Information Service (NTIS)

The report discusses the developmental modifications and evaluation of the Telephone Channel Monitor System. The system continuously monitors a communications channel on a noninterfering basis by combining a low-level, spread-spectrum, frequency-division-...

J. T. Richardson

1967-01-01

285

What's unique about unique entities? An fMRI investigation of the semantics of famous faces and landmarks.  

PubMed

Famous people and artifacts are referred to as "unique entities" (UEs) due to the unique nature of the knowledge we have about them. Past imaging and lesion experiments have indicated that the anterior temporal lobes (ATLs) as having a special role in the processing of UEs. It has remained unclear which attributes of UEs were responsible for the observed effects in imaging experiments. In this study, we investigated what factors of UEs influence brain activity. In a training paradigm, we systematically varied the uniqueness of semantic associations, the presence/absence of a proper name, and the number of semantic associations to determine factors modulating activity in regions subserving the processing of UEs. We found that a conjunction of unique semantic information and proper names modulated activity within a section of the left ATL. Overall, the processing of UEs involved a wider left-hemispheric cortical network. Within these regions, brain activity was significantly affected by the unique semantic attributes especially in the presence of a proper name, but we could not find evidence for an effect of the number of semantic associations. Findings are discussed in regard to current models of ATL function, the neurophysiology of semantics, and social cognitive processing. PMID:22021913

Ross, Lars A; Olson, Ingrid R

2012-09-01

286

What's Unique about Unique Entities? An fMRI Investigation of the Semantics of Famous Faces and Landmarks  

PubMed Central

Famous people and artifacts are referred to as “unique entities” (UEs) due to the unique nature of the knowledge we have about them. Past imaging and lesion experiments have indicated that the anterior temporal lobes (ATLs) as having a special role in the processing of UEs. It has remained unclear which attributes of UEs were responsible for the observed effects in imaging experiments. In this study, we investigated what factors of UEs influence brain activity. In a training paradigm, we systematically varied the uniqueness of semantic associations, the presence/absence of a proper name, and the number of semantic associations to determine factors modulating activity in regions subserving the processing of UEs. We found that a conjunction of unique semantic information and proper names modulated activity within a section of the left ATL. Overall, the processing of UEs involved a wider left-hemispheric cortical network. Within these regions, brain activity was significantly affected by the unique semantic attributes especially in the presence of a proper name, but we could not find evidence for an effect of the number of semantic associations. Findings are discussed in regard to current models of ATL function, the neurophysiology of semantics, and social cognitive processing.

Olson, Ingrid R.

2012-01-01

287

Nonlinear structural modification and nonlinear coupling  

NASA Astrophysics Data System (ADS)

Structural modification methods were proved to be very useful for large structures, especially when modification is local. Although there may be inherent nonlinearities in a structural system in various forms such as clearances, friction and cubic stiffness, most of the structural modification methods are for linear systems. The method proposed in this work is a structural modification/coupling method developed previously, and extended to systems with nonlinear modification and coupling. The method is most useful for large linear structures with nonlinear local modification or coupling. It is based on expressing nonlinear internal force vector in a nonlinear system as a response level dependent “equivalent stiffness matrix” (the so-called “nonlinearity matrix”) multiplied by the displacement vector, through quasilinearizing the nonlinearities using describing functions. Once nonlinear internal force vector is expressed as a matrix multiplication form then several structural modification and/or coupling methods can easily be used for nonlinear systems, provided that an iterative solution procedure is employed and convergence is obtained. In the proposed approach the nonlinear FRFs of a modified/coupled system are calculated from those of the original system and dynamic stiffness matrix of the nonlinear modifying system. Formulations and sample applications of the proposed approach for each of the following cases are given, nonlinear modification of a linear system with and without adding new degrees of freedom, and elastic coupling of a nonlinear subsystem to a main linear system with linear or nonlinear elements. Case studies are given for the verification of the method and then a real life application of the method is presented.

Kalayc?o?lu, Taner; Özgüven, H. Nevzat

2014-06-01

288

Characterization of Surface Modification of Polyethersulfone Membrane  

Microsoft Academic Search

Surface modification of polyethersulfone (PES) membrane surfaces using UV\\/ozone pretreatment with subsequent grafting and interfacial polymerization on membrane surface was investigated in order to improve the resistance of membrane surface to protein adsorption. The surface modifications were evaluated in terms of hydrophilicity, chemical composition of the surface and static protein adsorption. In both methods, poly(vinyl alcohol) (PVA), poly(ethylene glycol) (PEG)

Sean X. Liu; Jun-Tae Kim

2011-01-01

289

Surface and interface modification science and technology.  

SciTech Connect

Surface modification of solids is of scientific and technological interest due to its significant benefits in a wide variety of applications. Various coatings applications such as corrosion protection and electrical insulators and conductors are required for proper engineering design based on geometrical relationships between interfaces and on thermodynamic/kinetic considerations for the development of surface modifications. This paper will explore three basic examples: the proton conductor BaCeO{sub 3}, high-temperature protective coatings, and epitaxial relationships between interfaces.

Park, J.-H.

1999-07-19

290

Modifications of guanine bases during oligonucleotide synthesis.  

PubMed Central

Guanine bases are sensitive to modification during automated DNA synthesis and processing reactions. Methods for the detection of two types of guanine modifications are described. The first method uses the higher reactivity of the modified G base to KMn04 oxidation than T bases, and thus allows detection by chemical DNA sequencing. The second method makes use of the Escherichia coli nucleotide excision repair enzyme UvrABC endonuclease which can detect "bulky" base modifications at each nucleotide in the synthetic DNA. Though the chemical structures of the two modifications are not known, they may be related. Both types of G modifications are often found in oligonucleotides synthesized by the methoxy-diisopropyl-phosphoramidite (MEDP) chemistry but non-detectable in the products of the beta-cyanoethyl-diisopropyl-phosphoramidite (CEDP) chemistry. The Rubin and Schmid pyrimidine-specific chemical DNA sequencing procedure (Rubin, C.M., and Schmid, C.W. (1980) Nucleic Acids Res. 8, 4613-4619) was found to be applicable to oligonucleotides synthesized by the CEDP chemistry, and to oligonucleotides synthesized by the MEDP chemistry if precautionary measures are taken to destroy the signals produced by the highly KMnO4 sensitive modified guanine bases. We also show how chemical DNA sequencing might be useful for diagnosing other chemical modifications in synthetic oligonucleotides. Images

Yeung, A T; Dinehart, W J; Jones, B K

1988-01-01

291

Cone Photoreceptor Sensitivities and Unique Hue Chromatic Responses: Correlation and Causation Imply the Physiological Basis of Unique Hues  

PubMed Central

This paper relates major functions at the start and end of the color vision process. The process starts with three cone photoreceptors transducing light into electrical responses. Cone sensitivities were once expected to be Red Green Blue color matching functions (to mix colors) but microspectrometry proved otherwise: they instead peak in yellowish, greenish, and blueish hues. These physiological functions are an enigma, unmatched with any set of psychophysical (behavioral) functions. The end-result of the visual process is color sensation, whose essential percepts are unique (or pure) hues red, yellow, green, blue. Unique hues cannot be described by other hues, but can describe all other hues, e.g., that hue is reddish-blue. They are carried by four opponent chromatic response curves but the literature does not specify whether each curve represents a range of hues or only one hue (a unique) over its wavelength range. Here the latter is demonstrated, confirming that opponent chromatic responses define, and may be termed, unique hue chromatic responses. These psychophysical functions also are an enigma, unmatched with any physiological functions or basis. Here both enigmas are solved by demonstrating the three cone sensitivity curves and the three spectral chromatic response curves are almost identical sets (Pearson correlation coefficients r from 0.95–1.0) in peak wavelengths, curve shapes, math functions, and curve crossover wavelengths, though previously unrecognized due to presentation of curves in different formats, e.g., log, linear. (Red chromatic response curve is largely nonspectral and thus derives from two cones.) Close correlation combined with deterministic causation implies cones are the physiological basis of unique hues. This match of three physiological and three psychophysical functions is unique in color vision.

Pridmore, Ralph W.

2013-01-01

292

Identifying What Is Unique about the Social Studies. Bulletin 1.  

ERIC Educational Resources Information Center

A collection of six papers about the foundations and history of the social studies discipline focus on the task of identifying what is unique about social studies. The papers include: "Social Studies: Born Out of Crisis and Change" (James Barth); "A Coming of Age: Social Studies as a Proactive Force" (Walter Schultz); "Social Studies Education: A…

Barth, James L., Ed.

293

Occupationally Unique Interests in Scales on the Strong Interest Inventory  

Microsoft Academic Search

This study uncovered new occupationally specific dimensions that emerged from exploratory factor analysis of the female and male Business Education Teacher Occupational Scales of the Strong Interest Inventory (Strong; Harmon, Hansen, Borgen, & Hammer, 1994). The occupationally specific factors differed from the General Occupational Theme scales found on the Strong. Two confirmatory factor analyses were conducted to establish the uniqueness

Mark S. Majors; Lisa M. Larson

2001-01-01

294

A Unique Population: Women Who Are Homeless and Mentally Ill  

ERIC Educational Resources Information Center

This article describes a unique population within the homeless community--women who are homeless and mentally ill. Homelessness prevalence and etiology data are presented, followed by a general discussion of how mental illness affects people who are homeless. The article provides an overview of women who are homeless, focusing on those who are…

Markos, Patricia A.; Baron, Heather Lyn; Allen, Daniel N.

2005-01-01

295

Unique Sensor Plane Maps Invisible Toxins for First Responders  

SciTech Connect

A unique airborne emergency response tool, ASPECT is a Los Alamos/U.S. Environmental Protection Agency project that can put chemical and radiological mapping tools in the air over an accident scene. The name ASPECT is an acronym for Airborne Spectral Phot

2008-04-30

296

The unique radar properties of silicic lava domes  

Microsoft Academic Search

Silicic lava domes exhibit distinct morphologic characteristics at scales of centimeters to kilometers. Multiparameter radar observations capture the unique geometric signatures of silicic domes in a set of radar scattering properties that are unlike any other natural geologic surfaces. Backscatter cross-section values are among the highest observed on terrestrial lava flows and show only a weak decrease with incidence angle.

Jeffrey J. Plaut; Steven W. Anderson; David A. Crown; Ellen R. Stofan; Jakob J. van Zyl

2004-01-01

297

Unique MEMS characterization solutions enabled by laser Doppler vibrometer measurements  

Microsoft Academic Search

Micro-Electro-Mechanical Systems (MEMS) devices present many difficult characterization challenges. In an environment where dimensions are measured in microns and mechanical resonant frequencies are measured in kilohertz, conventional measurement and characterization techniques cannot be used. Laser Doppler Vibrometer (LDV) technology offers many unique advantages for MEMS characterization and troubleshooting. One of the key problems in characterizing and troubleshooting MEMS devices is

Kevin Speller; Howard Goldberg; Jeff Gannon; Eric M. Lawrence

2002-01-01

298

Unique Problems in Prosecuting Child Abuse Cases Overseas.  

National Technical Information Service (NTIS)

This thesis examines the unique problems present in prosecuting military family child abuse cases in the Republic of Korea (ROK). Research has shown that military families overseas tend to have higher levels of stress, hence they tend to be more prone to ...

M. T. Johnson

1991-01-01

299

Unique applications of underwater tooling: the TMI2 defueling experience  

Microsoft Academic Search

The complex task of safely removing the damaged core from Three Mile Island Unit 2 (TMI-2) is under way. Many unique underwater operations are being performed in the cut up and placement of the debris into defueling canisters, and a wide range of problems is being encountered and resolved. The unknown conditions beneath the upper core layer at TMI-2 during

R. L. Rider; R. J. Wolfgang; G. R. Skillman

1986-01-01

300

Duplicate bladder exstrophy: a unique approach to initial repair  

Microsoft Academic Search

Objectives. To describe a unique approach to the management of duplicate bladder exstrophy combining initial bladder closure and epispadias repair. Bladder exstrophy has been successfully managed by staged surgical repair with early bladder closure, subsequent epispadias repair, and, finally, bladder neck reconstruction. Duplicate bladder exstrophy is a rare variant of the exstrophy complex with fewer than 20 cases reported.Methods. A

Michael D Fabrizio; Stephen E Strup; R. Bruce Filmer; John Noseworthy; John P Gearhart

1999-01-01

301

The Lawn Hill Impact Structure: A Unique Terrestrial Crater?  

NASA Astrophysics Data System (ADS)

The Lawn Hill Impact Structure (LHIS) is located 250 km North of Mt Isa in Queensland. The structure consists of a central area ca. 8 km diameter enclosed by a ca. 5 km annulus of Cambrian limestone, a unique structure for terrestrial impacts.

Darlington, V. J.; Blenkinsop, T. G.; Orchiston, W.; Tomkins, A.

2012-09-01

302

Community Forums: A Unique Approach to Community Service-Learning  

ERIC Educational Resources Information Center

The service-learning movement has been criticized for not listening to the voices of community partners. Using Bourdieu's framework that equally values formal and practical knowledge, we evaluated a Manitoba college's service-learning program that focused on an issue of community concern. The program was uniquely designed to prioritize the voice…

Steiner, Sherrie; Warkentin, Buetta; Smith, Michael

2011-01-01

303

Unique waveform characteristics of current limiting fuse operations  

Microsoft Academic Search

This paper identifies and quantifies the unique characteristics of current-limiting fuse operation as seen in the current and voltage waveforms recorded at a monitoring station located upstream from the fault. Characteristics that can be used to identify current-limiting fuse operations by visual inspection are described. More characteristics are extracted using signal processing methods. These characteristics include but not limited to

Alicia J. Allen; Shivaz Chopra; Surya Santoso; Thomas A. Short

2010-01-01

304

Histology: a unique area of the medical laboratory  

Microsoft Academic Search

Fundamental differences in samples, procedures, nature of results, automation, productivity, staffing levels, and background decision making along work flow and turnaround times characterize histology as a unique area within the medical laboratory. For histology laboratories to function successfully, individual and collective training, well-defined goals, and implemented accountabilities with effective supervision are required. The pathologist, as immediate client of the histology

René J. Buesa

2007-01-01

305

Unique high density leadframe development for SOT23  

Microsoft Academic Search

With a drive of leading lower cost and higher productivity of Small Outline Surface Mounting (SOSM) packages, high density leadframe introduction was launched in the market since 21st century. But almost all factories use more expensive spot silver (Ag) plated and less than 60mm width leadframe. This paper presents the challenges faced and success in the development of unique high

Zhang Jingyuan; Ruan Jianhua

2008-01-01

306

A unique self-calibrating redundant inertial system  

NASA Astrophysics Data System (ADS)

A low-cost self-calibrating redundant inertial system is described. The developed DTG (dynamically tuned gyro) used in the system and the resulting unique system operation are well suited for applications where high reliability and rapid azimuth determination as well as accurate navigation are desirable.

Gilmore, Jerold P.; Musoff, Howard

307

Nickel: a unique allergen – from molecular structure to European legislation  

Microsoft Academic Search

Nickel is a unique, mysterious and troublesome chemical element. Its molecular structure (unfilled electron shell) determines the high-reactivity and multidirectional biological effects. Some authors classify nickel as trace element, although its biological role in animal and human metabolism remains unclear. Conversely, nickel possesses strong sensitizing potential: as many as 65 million Europeans may be allergic to nickel. In this article,

Radoslaw Spiewak; Justyna Pietowska; Katarzyna Curzytek

2007-01-01

308

Empirical chemical stratifications in magnetic Ap stars: questions of uniqueness  

Microsoft Academic Search

Over the last decades, modelling of the inhomogeneous vertical abundance distributions of various chemical elements in magnetic peculiar A type has largely relied on simple step-function approximations. In contrast, the recently introduced regularized vertical inversion procedure (VIP) is not based on parametrized stratification profiles and has been claimed to yield unique solutions without a priori assumptions as to the profile

M. J. Stift; G. Alecian

2009-01-01

309

Unique Features and Spacecraft Applications of Dynamic Isotope Power Systems  

Microsoft Academic Search

The dynamic isotope power system represents the most recent attempt to develop a heat-engine generator for space electric power. A major objective in this most recent effort was to increase the power and to reduce the cost of nuclear space power systems to the point where the unique features of this power source could be brought to bear for Earth-orbit

Raab

1982-01-01

310

Malignant PEComa involving the mandible: report of a unique case.  

PubMed

We report a unique case of a malignant perivascular epithelioid cell neoplasm (PEComa) presenting as a slow-growing mandibular lesion in a 77-year-old Caucasian female. Primary osseous involvement by PEComas is rare. This is the first reported case of a malignant PEComa arising within the jaw. The patient is currently free of disease 2 years after treatment. PMID:22901659

Untrauer, Jason B; Giannini, Peter J; Talmon, Geoffrey A; Johansson, Sonny L

2014-01-01

311

Unique chemical reactivity of a graphene nanoribbon's zigzag edge  

Microsoft Academic Search

The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. The authors investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A ``partial radical'' concept for the edge carbon atoms is introduced to characterize

De-En Jiang; Bobby G. Sumpter; Sheng Dai

2007-01-01

312

Unique Sensor Plane Maps Invisible Toxins for First Responders  

ScienceCinema

A unique airborne emergency response tool, ASPECT is a Los Alamos/U.S. Environmental Protection Agency project that can put chemical and radiological mapping tools in the air over an accident scene. The name ASPECT is an acronym for Airborne Spectral Phot

313

Unique Sensor Plane Maps Invisible Toxins for First Responders  

ScienceCinema

A unique airborne emergency response tool, ASPECT is a Los Alamos/U.S. Environmental Protection Agency project that can put chemical and radiological mapping tools in the air over an accident scene. The name ASPECT is an acronym for Airborne Spectral Phot

None

2010-01-08

314

Salad Bowl--All Together, All Unique, All Special.  

ERIC Educational Resources Information Center

Pluralism has become the word for this decade. America is no longer a melting pot, but a salad bowl where each person can retain his/her own uniqueness culturally. In a truly inclusive community, no one is exclusive or excluded. The legislature of South Dakota has mandated that all future teachers, as well as those teachers wishing to remain…

Mattson, Donald L.; Richardson, Maurine

315

ATTEMPT AT UNIQUE CLASSIFICATION OF RADIOELEMENTS ACCORDING TO THEIR RADIOTOXICITY  

Microsoft Academic Search

The unique classification offered by the authors is very similar to the ; one elaborated by the expents of A. I. E. A. who have, however, based their works ; on other considerations. Effectively, among the 236 radio-isotopes submitted to ; study, the differences concern only 5 of them which interest is, on the other ; hand, secondary: In\\/sup 115m\\/,

G. Vacca; A. Garnier; H. Jammet

1962-01-01

316

Quality Improvement in EMS: A Unique and Challenging Necessity.  

PubMed

Quality Improvement (QI) is required in all aspects of the healthcare field. Emergency Medical Services (EMS) poses unique QI challenges. This article explores some of these challenges and provides some points to consider when performing QI in EMS services. [Full text available at http://rimed.org/rimedicaljournal-2014-08.asp, free with no login]. PMID:25083952

Tsai, Devin; Choi, Bryan; Sullivan, Francis; Williams, Kenneth A

2014-01-01

317

Unique design of Doublet and Big Dee vacuum vessels  

Microsoft Academic Search

The Doublet III tokamak now in its fourth year of operation at General Atomic Company, has its plasma contained in a kidney-shaped toroidal vacuum vessel, a configuration that presented unique design challenges. Most tokamak vacuum vessels are constructed of solid walled sections separated by either thin walled bellows (to increase the toroidal resistance) or by poloidal insulation breaks. Such control

J. E. Miller

1982-01-01

318

Vertical microvia connections achieved using a unique conductive composite material  

Microsoft Academic Search

A novel base technology applicable to all major packaging and redistribution elements in an electronic module is presented. A unique polymer\\/metal composite conductor family based on transient liquid phase sintering (TLPS) can be used for chip package and PWB substrate applications, in interlayer connections, and for SMT assembly. High density multilayer circuits with landless blind and buried vias are fabricated

Goran Matijasevic; Pradeep Gandhi; Catherine Gallagher

1998-01-01

319

Sufficient conditions for uniqueness of the weak value  

NASA Astrophysics Data System (ADS)

We review and clarify the sufficient conditions for uniquely defining the generalized weak value as the weak limit of a conditioned average using the contextual values formalism introduced in Dressel, Agarwal and Jordan (2010 Phys. Rev. Lett. 104 240401). We also respond to criticism of our work by Parrott (arXiv:1105.4188v1) concerning a proposed counter-example to the uniqueness of the definition of the generalized weak value. The counter-example does not satisfy our prescription in the case of an underspecified measurement context. We show that when the contextual values formalism is properly applied to this example, a natural interpretation of the measurement emerges and the unique definition in the weak limit holds. We also prove a theorem regarding the uniqueness of the definition under our sufficient conditions for the general case. Finally, a second proposed counter-example by Parrott (arXiv:1105.4188v6) is shown not to satisfy the sufficiency conditions for the provided theorem.

Dressel, J.; Jordan, A. N.

2012-01-01

320

Uniqueness in the inverse scattering problem for Hartree type equation  

Microsoft Academic Search

In this paper we consider the inverse scattering problem for\\u000athe following Hartree type equation:\\u000a\\\\[ i\\\\frac{\\\\partial u}{\\\\partial t} = -\\\\varDelta u + (|x|^{-\\\\sigma} * |u|^2) u. \\\\]\\u000aWe prove the uniqueness theorem on the inverse scattering problem\\u000awith respect to the power $\\\\sigma$.

Michiyuki Watanabe

2001-01-01

321

A uniqueness result for a general glass of inverse problems  

SciTech Connect

In this paper, we prove that a bounded, compactly supported potential q can be uniquely determined by its scattering amplitude at a fixed non-L{sup 2} eigenvalue {lambda} {element_of} R for a general class of differential operators. 13 refs., 1 fig.

Liu, Changmei [Univ. of North Carolina, Chapel Hill, NC (United States)

1996-12-31

322

Unique Relations of Age and Delinquency with Cognitive Control  

ERIC Educational Resources Information Center

Context processing has significant empirical support as an explanation of age- and psychopathology-related deficiencies in cognitive control. We examined whether context processing generalizes to younger individuals who are in trouble with the law. We tested whether age and delinquency might have unique relations to context processing skills in…

Iselin, Anne-Marie R.; DeCoster, Jamie

2012-01-01

323

A unique form of endemic pemphigus in northern Colombia  

Microsoft Academic Search

Endemic forms of pemphigus are a unique group of autoimmune diseases that represent opportunities to study interactions of the environment and genetics with the immune system. The restriction to relatively well-defined regions of South and Central America and perhaps Africa characterizes these diseases. OBJECTIVES: The aims of this study were to confirm the endemic nature of a new type of

Ana María Abrèu-Velez; Takashi Hashimoto; Wendy B. Bollag; Sergio Tobón Arroyave; Clara Eugenia Abrèu-Velez; Martha Luz Londoño; Fernando Montoya; Ernst H. Beutner

2003-01-01

324

Non-uniqueness in spin-DFT on small lattices  

NASA Astrophysics Data System (ADS)

In non-magnetic systems, the electronic ground-state densities are uniquely determined by the external potentials. In the presence of magnetic fields (coupling to the spins only), the mapping between densities and magnetizations, n(r) and m(r), and potentials and magnetic fields, v(r) and B(r), is no longer unique, as was recognized long ago [1] and discussed in more detail recently [2,3]. This has practical consequences e.g. for the spin gaps of half-metallic ferromagnets. This talk discusses non-uniqueness in spin-DFT for two non-interacting electrons on small lattices with arbitrary potentials and magnetic fields. These model systems have the advantage that the (n,m) and (v,B) parameter spaces can be systematically explored. Different types of non-uniqueness are discovered: some were previously predicted [2,3], others are new and specific to lattices. [1] U. von Barth and L. Hedin, J. Phys. C 5, 1629 (1972) [2] H. Eschrig and W.E. Pickett, Solid State Commun. 118, 123 (2001) [3] K. Capelle and G. Vignale, Phys. Rev. Lett. 86, 5546 (2001)

Ullrich, Carsten A.

2004-03-01

325

On pathwise uniqueness of stochastic evolution equations in Hilbert spaces  

NASA Astrophysics Data System (ADS)

The pathwise uniqueness of stochastic evolution equations driven by Q-Wiener processes is mainly investigated in this article. We focus on the case that the modulus of the continuity of the coefficients is not controlled by a linear function. Additionally, we show that the corresponding diffusion process is Feller.

Xie, Bin

2008-08-01

326

Centromeres: unique chromatin structures that drive chromosome segregation  

Microsoft Academic Search

Fidelity during chromosome segregation is essential to prevent aneuploidy. The proteins and chromatin at the centromere form a unique site for kinetochore attachment and allow the cell to sense and correct errors during chromosome segregation. Centromeric chromatin is characterized by distinct chromatin organization, epigenetics, centromere-associated proteins and histone variants. These include the histone H3 variant centromeric protein A (CENPA), the

Jolien S. Verdaasdonk; Kerry Bloom

2011-01-01

327

Some uniqueness theorems in the theory of elasticity  

Microsoft Academic Search

I. Introduction In the usual treatment of problem, s in classical elasticity it is shown that if the shear modulus ~u is positive and Poisson's ratio ~ lies in the interval I x (--t unique solutions (up to possible rigid body motiolas). Recently a number of authors [2--9] have pointed out

J. H. Bramble; L. E. Payne

1962-01-01

328

A Uniqueness Theorem in the Theory of Cosserat Surface.  

National Technical Information Service (NTIS)

Within the scope of the non-isothermal theory of an elastic Cosserat surface and for a system of linear equations characterizing the initial mixed boundary-value problems of thermoelastic shells, a uniqueness theorem is obtained without the use of definit...

P. M. Naghdi J. A. Trapp

1971-01-01

329

Is Self-Assessment in Religious Education Unique?  

ERIC Educational Resources Information Center

This paper addresses the question: is self-assessment in religious education unique? It first presents an overview of some challenges for assessment from subject differences, and then reviews the generic literature on self-assessment. It builds on earlier empirical research on self-assessment in religious education, carried out in an English state…

Brooks, Val; Fancourt, Nigel

2012-01-01

330

Non-unique Probe Selection with Group Testing  

Microsoft Academic Search

Non-unique probe selection is an important research problem in computational molecu- lar biology. One of approaches to study it is group testing. A minization problem arosen from such study is as follows: Give a binary matrix, find a d-disjunct submatrix with the minimum number of rows and the same number of columns. We give a mini survey on its computational

Ping Deng; Feng Wang; Ding-Zhu Du

2007-01-01

331

Unique man-portable five-element fluxgate gradiometer system  

Microsoft Academic Search

In the past, fluxgate magnetometers have been limited to stationary applications due to their vector nature. Because of its small relative size and cost, many additional potential uses and applications for the fluxgate magnetometer would be generated if this inherent motion noise could be eliminated. This paper describes a unique hardware solution that when coupled with a set of robust

George I. Allen; Roger H. Koch; George Keefe

1995-01-01

332

On Time Delay Margin Estimation for Adaptive Control and Optimal Control Modification  

NASA Technical Reports Server (NTRS)

This paper presents methods for estimating time delay margin for adaptive control of input delay systems with almost linear structured uncertainty. The bounded linear stability analysis method seeks to represent an adaptive law by a locally bounded linear approximation within a small time window. The time delay margin of this input delay system represents a local stability measure and is computed analytically by three methods: Pade approximation, Lyapunov-Krasovskii method, and the matrix measure method. These methods are applied to the standard model-reference adaptive control, s-modification adaptive law, and optimal control modification adaptive law. The windowing analysis results in non-unique estimates of the time delay margin since it is dependent on the length of a time window and parameters which vary from one time window to the next. The optimal control modification adaptive law overcomes this limitation in that, as the adaptive gain tends to infinity and if the matched uncertainty is linear, then the closed-loop input delay system tends to a LTI system. A lower bound of the time delay margin of this system can then be estimated uniquely without the need for the windowing analysis. Simulation results demonstrates the feasibility of the bounded linear stability method for time delay margin estimation.

Nguyen, Nhan T.

2011-01-01

333

Discovery of GW870086: a potent anti-inflammatory steroid with a unique pharmacological profile  

PubMed Central

Background and Purpose Glucocorticoids are highly effective therapies for a range of inflammatory diseases. Advances in the understanding of the diverse molecular mechanisms underpinning glucocorticoid action suggest that anti-inflammatory molecules with reduced side effect liabilities can be discovered. Here we set out to explore whether modification of the 17? position of the steroid nucleus could generate molecules with a unique pharmacological profile and to determine whether such molecules would retain anti-inflammatory activity. Experimental Approach The pharmacological properties of GW870086 were compared with fluticasone propionate (FP) using a range of cellular and in vivo model systems, including extensive gene expression profiling. Key Results GW870086 repressed inflammatory cytokine release from lung epithelial cells in a similar manner to FP but antagonized the effect of dexamethasone on MMTV-driven reporter gene transactivation. GW870086 had a strong effect on the expression of some glucocorticoid-regulated genes (such as PTGS2), while having minimal impact on the expression of other known target genes (such as SGK). GW870086 retained the ability to strengthen tight junctions in epithelial cell culture but, unlike FP, was unable to protect the culture from elastase-mediated damage. In murine models of irritant-induced contact dermatitis and ovalbumin-induced allergic inflammation, GW870086 showed comparable anti-inflammatory efficacy to FP. Conclusion and Implications GW870086 is a potent anti-inflammatory compound with a unique ability to regulate only a subset of those genes that are normally affected by classical glucocorticoids. It has the potential to become a new topical steroid with a different safety profile to existing therapies.

Uings, I J; Needham, D; Matthews, J; Haase, M; Austin, R; Angell, D; Leavens, K; Holt, J; Biggadike, K; Farrow, S N

2013-01-01

334

Sequence tagging reveals unexpected modifications in toxicoproteomics  

PubMed Central

Toxicoproteomic samples are rich in posttranslational modifications (PTMs) of proteins. Identifying these modifications via standard database searching can incur significant performance penalties. Here we describe the latest developments in TagRecon, an algorithm that leverages inferred sequence tags to identify modified peptides in toxicoproteomic data sets. TagRecon identifies known modifications more effectively than the MyriMatch database search engine. TagRecon outperformed state of the art software in recognizing unanticipated modifications from LTQ, Orbitrap, and QTOF data sets. We developed user-friendly software for detecting persistent mass shifts from samples. We follow a three-step strategy for detecting unanticipated PTMs in samples. First, we identify the proteins present in the sample with a standard database search. Next, identified proteins are interrogated for unexpected PTMs with a sequence tag-based search. Finally, additional evidence is gathered for the detected mass shifts with a refinement search. Application of this technology on toxicoproteomic data sets revealed unintended cross-reactions between proteins and sample processing reagents. Twenty five proteins in rat liver showed signs of oxidative stress when exposed to potentially toxic drugs. These results demonstrate the value of mining toxicoproteomic data sets for modifications.

Dasari, Surendra; Chambers, Matthew C.; Codreanu, Simona G.; Liebler, Daniel C.; Collins, Ben C.; Pennington, Stephen R.; Gallagher, William M.; Tabb, David L.

2010-01-01

335

Lysine post-translational modifications of collagen  

PubMed Central

Type I collagen is the most abundant structural protein in vertebrates. It is a heterotrimeric molecule composed of two ?1 chains and one ?2 chain, forming a long uninterrupted triple helical structure with short non-triple helical telopeptides at both the N- and C-termini. During biosynthesis, collagen acquires a number of post-translational modifications, including lysine modifications, that are critical to the structure and biological functions of this protein. Lysine modifications of collagen are highly complicated sequential processes catalysed by several groups of enzymes leading to the final step of biosynthesis, covalent intermolecular cross-linking. In the cell, specific lysine residues are hydroxylated to form hydroxylysine. Then specific hydroxylysine residues located in the helical domain of the molecule are glycosylated by the addition of galactose or glucose-galactose. Outside the cell, lysine and hydroxylysine residues in the N- and C-telopeptides can be oxidatively deaminated to produce reactive aldehydes that undergo a series of non-enzymatic condensation reactions to form covalent intra- and inter-molecular cross-links. Owing to the recent advances in molecular and cellular biology, and analytical technologies, the biological significance and molecular mechanisms of these modifications have been gradually elucidated. This chapter provides an overview on these enzymatic lysine modifications and subsequent cross-linking.

Yamauchi, Mitsuo; Sricholpech, Marnisa

2012-01-01

336

Heterogeneous polymer modification: Polyolefin maleation in supercritical carbon dioxide and amorphous fluoropolymer surface modification  

Microsoft Academic Search

Three distinct heterogeneous polymer modification reactions are explored in this work. The first is a bulk reaction commonly conducted on polyolefins---the free radical addition of maleic anhydride. This reaction was run using supercritical carbon dioxide (SC CO2) as the solvent. The second was the chemical surface modification of an amorphous fluorocopolymer of tetrafluoroethylene and a perfluorodioxole monomer (Teflon AF). Several

Heather J. Hayes

1999-01-01

337

Unique chemical reactivity of a graphene nanoribbon's zigzag edge.  

PubMed

The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. The authors investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A "partial radical" concept for the edge carbon atoms is introduced to characterize their chemical reactivity, and the validity of this concept is verified by comparing the dissociation energies of edge-radical bonds with similar bonds in molecules. In addition, the uniqueness of the zigzag-edged graphene nanoribbon is further demonstrated by comparing it with other forms of sp2 carbons, including a graphene sheet, nanotubes, and an armchair-edged graphene nanoribbon. PMID:17430050

Jiang, De-en; Sumpter, Bobby G; Dai, Sheng

2007-04-01

338

The unique chemical reactivity of a graphene nanoribbon's zigzag edge  

SciTech Connect

The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. We investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A "partial radical? concept for the edge carbon atoms is introduced to characterize their chemical reactivity, and the validity of this concept is verified by comparing the dissociation energies of edge-radical bonds with similar bonds in molecules. In addition, the uniqueness of the zigzag-edged graphene nanoribbon is further demonstrated by comparing it with other forms of sp2 carbons, including a graphene sheet, nanotubes, and an armchair-edged graphene nanoribbon.

Jiang, Deen [ORNL; Dai, Sheng [ORNL; Sumpter, Bobby G [ORNL

2007-01-01

339

Unique research challenges for high-speed civil transports  

NASA Technical Reports Server (NTRS)

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Jackson, Charlie M., Jr.; Morris, Charles E. K., Jr.

1987-01-01

340

Erdheim chester - A rare disease with unique endoscopic features  

PubMed Central

Erdheim-Chester disease (ECD) is a rare inflammatory syndrome in which systemic infiltration of non-Langerhans cell histiocytes occurs in different sites. Both the etiology and pathophysiology of ECD are unknown, but CD68 positive CD 1a/S100 negative cells are characteristic. The presentation of ECD differs according to the involved organs. This case report describes a patient with ECD and the gastrointestinal manifestations and unique endoscopic appearance as seen in gastroscopy and colonoscopy with histological proof of histiocyte infiltration of the lamina propria. The clinical and endoscopic findings of this unique case, to our knowledge, were never described before, so were the features of the gastrointestinal involvement in this disease.

Ben-yaakov, Gil; Munteanu, Daniela; Sztarkier, Ignacio; Fich, Alexander; Schwartz, Doron

2014-01-01

341

The unique protein kinase C?: Implications for breast cancer (Review).  

PubMed

Deregulation of key signal transduction pathways that govern important cellular processes leads to cancer. The development of effective therapeutics for cancer warrants a comprehensive understanding of the signaling pathways that are deregulated in cancer. The protein kinase C (PKC) family has served as an attractive target for cancer therapy for decades owing to its crucial roles in several cellular processes. PKC? is a novel member of the PKC family that plays critical roles in various cellular processes such as growth, proliferation, differentiation and cell death. The regulation of PKC? appears to be unique compared to other PKC isozymes, and there are conflicting reports regarding its role in cancer. This review focuses on the unique aspects of PKC? in terms of its structure, regulation and subcellular distribution and speculates on how these features could account for its distinct functions. We have also discussed the functional implications of PKC? in cancer with particular emphasis on breast cancer. PMID:24841225

Pal, Deepanwita; Basu, Alakananda

2014-08-01

342

Occupational status differences in attributions of uniquely human emotions.  

PubMed

Infrahumanization theory has claimed that groups tend to infrahumanize, and thus denigrate, each other irrespective of group status. However, research on infrahumanization has mainly addressed status in the context of national, ethnic, and regional divisions. The present studies tested the effect of group status in infrahumanization by employing occupational groups of varied status, both in abstract (blue-collar vs. white-collar workers) and specific terms (lawyers vs. shopkeepers, and high school teachers vs. university faculty members and primary school teachers). The results showed that only relatively higher status groups always attributed uniquely human emotions more to their in-group than to lower status out-groups. In contrast, lower status groups showed no bias in attributions of uniquely human emotions, or were biased in favour of the higher status out-group. The discussion of these results points to the role of consensus in the distribution of social value amongst groups of asymmetric status. PMID:22353014

Iatridis, Tilemachos

2013-09-01

343

A Unique Rheology / SAXS Combination at DESY / Petra III  

NASA Astrophysics Data System (ADS)

Progress in the development of synchrotron radiation sources, x-ray optics and detectors brings new possibilities in x-ray instrumentation. At the P10 beamline of PETRA III, a unique rheology / SAXS setup was successfully integrated and commissioned to gain new insight in the molecular arrangement of complex fluids and soft matter under shear conditions. The setup is based on an inverted Thermo Fisher Haake Mars II rheometer with a horizontal plate/plate or cone/plate geometry, specifically designed to be probed by a vertically deflected synchrotron X-ray beam. The main advantage of this kind of configuration is the unique possibility to scan the molecular arrangement of fluid matter along the shear gradient under a variety of shear conditions. In this way, very well defined experimental conditions can be provided and molecular arrangements that are otherwise inaccessible in plate / plate geometries can be directly examined.

Stellamanns, E.; Meissner, D.; Lohmann, M.; Struth, B.

2013-03-01

344

Unique research challenges for high-speed civil transports  

NASA Technical Reports Server (NTRS)

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Jackson, Charlie M., Jr.; Morris, E. K., Jr.

1988-01-01

345

WURCS: The Web3 Unique Representation of Carbohydrate Structures.  

PubMed

In recent years, the Semantic Web has become the focus of life science database development as a means to link life science data in an effective and efficient manner. In order for carbohydrate data to be applied to this new technology, there are two requirements for carbohydrate data representations: (1) a linear notation which can be used as a URI (Uniform Resource Identifier) if needed and (2) a unique notation such that any published glycan structure can be represented distinctively. This latter requirement includes the possible representation of nonstandard monosaccharide units as a part of the glycan structure, as well as compositions, repeating units, and ambiguous structures where linkages/linkage positions are unidentified. Therefore, we have developed the Web3 Unique Representation of Carbohydrate Structures (WURCS) as a new linear notation for representing carbohydrates for the Semantic Web. PMID:24897372

Tanaka, Kenichi; Aoki-Kinoshita, Kiyoko F; Kotera, Masaaki; Sawaki, Hiromichi; Tsuchiya, Shinichiro; Fujita, Noriaki; Shikanai, Toshihide; Kato, Masaki; Kawano, Shin; Yamada, Issaku; Narimatsu, Hisashi

2014-06-23

346

21 CFR 1301.51 - Modification in registration.  

Code of Federal Regulations, 2010 CFR

...CONTROLLED SUBSTANCES Modification, Transfer and Termination...Registration § 1301.51 Modification in registration...copies of a research protocol describing each research...to be paid for the modification. The request for modification...the same manner as an application for...

2010-04-01

347

21 CFR 1301.51 - Modification in registration.  

Code of Federal Regulations, 2010 CFR

...CONTROLLED SUBSTANCES Modification, Transfer and Termination...Registration § 1301.51 Modification in registration...copies of a research protocol describing each research...to be paid for the modification. The request for modification...the same manner as an application for...

2009-04-01

348

Optimization of diagonal chromatography for recognizing post-translational modifications  

Microsoft Academic Search

Post-translational modifications modulate the activity of most eukaryote proteins. Analysis of these modifications presents a formidable analytical challenge. This paper examines the potential of diagonal chromatography for recognizing post-translational modifications. Diagonal chromatography is the process of using the same chromatographic separation in two dimensions. Between the two dimensions, a chemical modification is applied to all fractions. Substances that have been

Peiran Liu; Christa L. Feasley; Fred E. Regnier

2004-01-01

349

A Unique Iontophoretic Patch for Optimal Transdermal Delivery of Sumatriptan  

Microsoft Academic Search

Purpose  Migraines affect approximately 10% of the adult population worldwide. The purpose of this study was to assess the pharmacokinetic\\u000a and safety profile of a novel iontophoretic sumatriptan delivery system, NP101, which uses an electrical current to propel\\u000a sumatriptan across intact skin and into underlying tissue. Four unique prototype iontophoretic sumatriptan patch conditions\\u000a were compared to a 6 mg subcutaneous injection and

Steven J. Siegel; Carol O’Neill; Louise M. Dubé; Peter Kaldeway; Russell Morris; David Jackson; Terri Sebree

2007-01-01

350

Human lung expresses unique gamma-glutamyl transpeptidase transcripts.  

PubMed Central

gamma-Glutamyl transpeptidase (EC 2.3.2.2, gamma GT) is a membrane-bound ectoenzyme that plays an important role in the metabolism of glutathione. It is composed of two subunits, both of which are encoded by a common mRNA. We examined the expression of gamma GT in human lung tissue by Northern blot analysis and screening a cDNA library made from human lung poly(A)+ RNA. Our results show that there are two gamma GT mRNA populations in human lung tissue. We define these as group I (2.4 kb) and group II (approximately 1.2 kb) transcripts. In the present communication, we characterize the unique lung transcript. Sequence analysis of representative clones shows that group I transcripts are virtually identical to those previously isolated from liver and placenta but possess a unique 5' untranslated region. In marked contrast, group II transcripts appear to be human-lung-specific. Group II transcripts appear on Northern blots probed with full-length or 3'-biased gamma GT cDNA. Sequence analysis of group II clones shows them to be homologous with group I clones in the region that encodes the reading frame for the light chain; however, they possess a series of unique 5' untranslated regions, which suggests that they arise from lung-specific message processing. Additionally, approximately 50% of the isolated group II clones contain 34 nt substitutions compared with the "wild-type" gamma GT transcripts. These data indicate that human lung expresses unique gamma GT transcripts of unknown function as well as the classical form. The abundant group II transcripts may encode part of a heterodimer related to gamma GT or represent processed lung-specific pseudogenes. Images Fig. 1

Wetmore, L A; Gerard, C; Drazen, J M

1993-01-01

351

The unique signal concept for detonation safety in nuclear weapons  

SciTech Connect

The purpose of a unique signal (UQS) in a nuclear weapon system is to provide an unambiguous communication of intent to detonate from the UQS information input source device to a stronglink safety device in the weapon in a manner that is highly unlikely to be duplicated or simulated in normal environments and in a broad range of ill-defined abnormal environments. This report presents safety considerations for the design and implementation of UQSs in the context of the overall safety system.

Spray, S.D.; Cooper, J.A.

1993-06-01

352

Unique and shared functions of different connexins in mice  

Microsoft Academic Search

Background: Connexins are the protein subunits of intercellular gap junction channels. In mammals, they are encoded by a family of at least 15 genes, which show cell-type-specific but overlapping patterns of expression. Mice lacking connexin43 (Cx43) die postnatally from obstruction of the right ventricular outflow tract of the heart. To discriminate between the unique and shared functions of Cx43, Cx40

A. Plum; G. Hallas; T. Magin; F. Dombrowski; A. Hagendorff; B. Schumacher; C. Wolpert; J. S. Kim; W. H. Lamers; M. Evert; P. Meda; O. Traub; K. Willecke

2000-01-01

353

The Mysteries of Diamonds: Bizarre History, Amazing Properties, Unique Applications  

SciTech Connect

Diamonds have been a prized material throughout history. They are scarce and beautiful, wars have been fought over them, and they remain today a symbol of wealth and power. Diamonds also have exceptional physical properties which can lead to unique applications in science. There are now techniques to artificially synthesize diamonds of extraordinarily high quality. In this talk, Professor Kagan will discuss the history of diamonds, their bizarre properties, and their manufacture and use for 21st century science.

Kagan, Harris (Ohio State University) [Ohio State University

2008-06-24

354

Unique properties of nano-engineered optical materials  

Microsoft Academic Search

Nanotechnologies are used to study matter at the nanometric scale and enable new technological & scientific possibilities. Since structural properties at the nanometric scale also define their macroscopic behaviors, it is now clear that materials nano-engineering can provide a unique control over their physical properties unavailable otherwise. In this work, template-assisted optical-material nano-engineering is used to enable novel material properties

Sylvain G. Cloutier

2006-01-01

355

Concentration and Mindfulness Meditations: Unique Forms of Consciousness?  

Microsoft Academic Search

Electroencephalographic (EEG) recordings from 19 scalp recording sites were used to differentiate among two posited unique forms of mediation, concentration and mindfulness, and a normal relaxation control condition. Analyzes of all traditional frequency bandwidth data (i.e., delta 1–3 Hz; theta, 4–7 Hz; alpha, 8–12 Hz; beta 1, 13–25 Hz; beta 2, 26–32 Hz) showed strong mean amplitude frequency differences between

Bruce R. Dunn; Judith A. Hartigan; William L. Mikulas

1999-01-01

356

Determining Horizontal Gene Transfers in Species Classification: Unique Scenario  

Microsoft Academic Search

\\u000a The problem of species classification, taking into account the mechanisms of reticulate evolution such as horizontal gene\\u000a transfer (HGT), species hybridization,or gene duplication, is very delicate. In this paper, we describe a new algorithm for\\u000a determining a unique scenario of HGT events in a given additive tree (i.e., a phylogenetic tree) representing the evolution\\u000a of a group of species. The

Vladimir Makarenkov; Alix Boc; Abdoulaye Baniré Diallo

357

A unique multipurpose damping circuit for shunt capacitor bank switching  

SciTech Connect

Considerations on disturbances related to Shunt Capacitor Bank (SCB) switching are summarized and a unique damping circuit able to cope with all of them is proposed. This damping circuit consists of a reactor in parallel with a resistor which is in series with a Metal Oxide Varistor (MOV), the latter being used to switch on the resistor only during transients. The design parameter of this damping circuit are described and the main tests performed are presented.

Sabot, A.; Morin, C.; Guillaume, C.; Pons, A. (Electricite de France, Les Renardieres (France). Les Renardieres Lab.); Taisne, J.P. (Electricite de France, Les Renardieres (France). Transmission Division); Pizzo, G.L.; Morf, H.U. (Haefely S.A., Saint Louis (France))

1993-07-01

358

The unique story of a high-tech polymer  

Microsoft Academic Search

Man has always dreamt of making a strong, diamond-like fiber. The hardness of diamond is due to its unique structure with only C-C single bonds. It is presumed that long straight chain of C-C bonds may produce the fiber which could have super-strength. Most polymers, due to random orientation of the back-bone chain, produce fibers of weak strength. It is

Panchanan Pramanik; Ruby Chakraborty

2004-01-01

359

Fenestranes in synthesis: unique and highly inspiring scaffolds.  

PubMed

The scaffold of fenestranes is quite unique, as it contains four condensed cycles and a distorted tetracoordinated central carbon atom with bond angles greater than the regular 109°28". In this Minireview, a detailed overview on the developments regarding this compound class, including their synthesis, is given for the time period since 2006. In the past years, natural products that belong to the class of heterofenestranes have been isolated and their syntheses will also be discussed. PMID:24281879

Boudhar, Aicha; Charpenay, Mélanie; Blond, Gaëlle; Suffert, Jean

2013-12-01

360

Cavernous hemangioma-like kaposi sarcoma: a unique histopathologic variant.  

PubMed

: Kaposi sarcoma (KS) is an angiolymphatic neoplasm with multifactorial etiology. Clinically, KS has been divided into 4 distinct types and 3 well-defined histologic stages. Rare reports in the literature have characterized additional unique histopathologic variants. The authors report a case of KS, confirmed with human herpesvirus type 8 and D2-40 staining, which resembled a cavernous hemangioma on histopathology. PMID:24803066

Sutton, Angela M; Tarbox, Michelle; Burkemper, Nicole M

2014-05-01

361

Unique Case of "Post-Lumbar Puncture Headache"  

PubMed Central

Lumbar puncture (LP) is associated with complications that include post-LP orthostatic headache, local bleeding, and subdural hematoma. We report a unique case of a spontaneous frontal epidural hematoma following a therapeutic lumbar puncture in a patient with a history of idiopathic intracranial hypertension. This case highlights the importance of symptomatology in patients following LPs by revealing a rare intracranial presentation that would be devastating if not discovered promptly and appropriately managed.

Patel, Bimal A.; Williams, Nolan R.; Pritchard, Paul B.

2014-01-01

362

Existence and uniqueness theorems for the algebraic Riccati equation  

Microsoft Academic Search

Necessary and sufficient conditions for existence and uniqueness of hermitian solutions of the algebraic n×n matrix Riccati equation(D?0,C=C,(A, D) controllable) are obtained. The conditions are formulated in terms of the spectral structure of a certain 2n × 2n matrix. A description is also given of the set of solutions in a geometrical language of invariant subspaces which are neutral with

P. LANCASTER; L. RODMAN

1980-01-01

363

The Galactic nucleus: A unique region in the Galactic ecosystem  

NASA Technical Reports Server (NTRS)

The nucleus is a unique region in the Galactic ecosystem. It is also superb laboratory of modern astrophysics where astronomers can study, at unprecedented spatial resolution and across the entire electromagnetic spectrum, physical processes that may also happen at the cores of other galaxies. Infrared observations from the Kuiper Airborne Observatory have made important contributions to unraveling the mysteries of the Galactic nucleus and this review highlights some of these measurements, as well as recent results regarding the central parsec.

Genzel, Reinhard; Poglitsch, Albrecht

1995-01-01

364

Plastic-casting intrinsic-surface unique identifier (tag)  

SciTech Connect

This report describes the development of an authenticated intrinsic-surf ace tagging method for unique- identification of controlled items. Although developed for control of items limited by an arms control treaty, this method has other potential applications to keep track of critical or high-value items. Each tag (unique-identifier) consists of the intrinsic, microscopic surface topography of a small designated area on a controlled item. It is implemented by making a baseline plastic casting of the designated tag area and usually placing a cover (for example, a bar-code label) over this area to protect the surface from environmental alteration. The plastic casting is returned to a laboratory and prepared for high-resolution scanning electron microscope imaging. Several images are digitized and stored for use as a standard for authentication of castings taken during future inspections. Authentication is determined by numerically comparing digital images. Commercially available hardware and software are used for this tag. Tag parameters are optimized, so unique casting images are obtained from original surfaces, and images obtained from attempted duplicate surfaces are detected. This optimization uses the modulation transfer function, a first principle of image analysis, to determine the parameters. Surface duplication experiments confirmed the optimization.

Palm, R.G.; De Volpi, A.

1995-04-01

365

Biosynthetic Potential of Phylogenetically Unique Endophytic Actinomycetes from Tropical Plants? †  

PubMed Central

The culturable diversity of endophytic actinomycetes associated with tropical, native plants is essentially unexplored. In this study, 123 endophytic actinomycetes were isolated from tropical plants collected from several locations in Papua New Guinea and Mborokua Island, Solomon Islands. Isolates were found to be prevalent in roots but uncommon in leaves. Initially, isolates were dereplicated to the strain level by ribotyping. Subsequent characterization of 105 unique strains by 16S rRNA gene sequence analysis revealed that 17 different genera were represented, and rare genera, such as Sphaerisporangium and Planotetraspora, which have never been previously reported to be endophytic, were quite prevalent. Phylogenetic analyses grouped many of the strains into clades distinct from known genera within Thermomonosporaceae and Micromonosporaceae, indicating that they may be unique genera. Bioactivity testing and liquid chromatography-mass spectrometry (LC-MS) profiling of crude fermentation extracts were performed on 91 strains. About 60% of the extracts exhibited bioactivity or displayed LC-MS profiles with spectra indicative of secondary metabolites. The biosynthetic potential of 29 nonproductive strains was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. Despite their lack of detectable secondary metabolite production in fermentation, most were positive for type I (66%) and type II (79%) PKS genes, and all were positive for NRPS genes. These results suggest that tropical plants from New Guinea and the adjacent archipelago are hosts to unique endophytic actinomycetes that possess significant biosynthetic potential.

Janso, Jeffrey E.; Carter, Guy T.

2010-01-01

366

Empirical chemical stratifications in magnetic Ap stars: questions of uniqueness  

NASA Astrophysics Data System (ADS)

Over the last decades, modelling of the inhomogeneous vertical abundance distributions of various chemical elements in magnetic peculiar A type has largely relied on simple step-function approximations. In contrast, the recently introduced regularized vertical inversion procedure (VIP) is not based on parametrized stratification profiles and has been claimed to yield unique solutions without a priori assumptions as to the profile shapes. It is the question of uniqueness of empirical stratifications which is at the centre of this article. An error analysis establishes confidence intervals about the abundance profiles and it is shown that many different step functions of sometimes widely different amplitudes give fits to the observed spectra which equal the VIP fits in quality. Theoretical arguments are advanced in favour of abundance profiles that depend on magnetic latitude, even in moderately strong magnetic fields. Including cloud, cap and ring models in the discussion, it is shown that uniqueness of solutions cannot be achieved without phase-resolved high signal-to-noise ratio and high spectral resolution (R) spectropolarimetry in all four Stokes parameters.

Stift, M. J.; Alecian, G.

2009-04-01

367

Unique symbol for marking and tracking very small semiconductor products  

NASA Astrophysics Data System (ADS)

The problem of tracking very small semiconductor products with a bar code is easily overcome by the use of the matrix symbol, which is a unique two-dimensional symbol that is the most space efficient method of packing binary data. It is both machine written and machine read to provide the utmost in accuracy and repeatability. The number of data cells can either be expanded or contracted to handle the required information and in addition can contain parity and error correcting codes. Semiconductor chips, wafers, substrates, modules and even masks can all be laser marked with this symbol and quickly read at any later stage of the manufacturing process. This unique symbol is computer generated by a software algorithm which creates the data cells and data frame which are laser etched on the product. On-line product identification yields immediate benefits in manufacturing such as inventory control, proper mating of parts, proper selection of test programs, quality control, etc. Use of a very small unique machine readable symbol now permits these benefits to be extended to miniature parts in an automated high speed manufacturing line.

Martin, James P.

1991-12-01

368

Body modifications, sexual activity, and religious practices.  

PubMed

Relations among body modifications (i.e., tattoos and piercings), sexual activity, and religious practices and beliefs were examined. In previous studies, Koch and colleagues found the type of body modification seemed to interact with sex to predict sexual activity; but only weak, negative correlations were found between tattoos and religious beliefs and practices. In a sample of 236 students (M age=20.1 yr.) from a small Catholic liberal arts college, numbers of tattoos and sexual partners were correlated statistically significantly. Other results differed by t sex: men with piercings were more likely to have had premarital intercourse, and women who had had premarital intercourse had more piercings than women who had not. There were no statistically significant correlations among body modifications and religious variables. PMID:20524547

Rivardo, Mark G; Keelan, Colleen M

2010-04-01

369

Modification Site Localization Scoring: Strategies and Performance  

PubMed Central

Using enrichment strategies many research groups are routinely producing large data sets of post-translationally modified peptides for proteomic analysis using tandem mass spectrometry. Although search engines are relatively effective at identifying these peptides with a defined measure of reliability, their localization of site/s of modification is often arbitrary and unreliable. The field continues to be in need of a widely accepted metric for false localization rate that accurately describes the certainty of site localization in published data sets and allows for consistent measurement of differences in performance of emerging scoring algorithms. In this article are discussed the main strategies currently used by software for modification site localization and ways of assessing the performance of these different tools. Methods for representing ambiguity are reviewed and a discussion of how the approaches transfer to different data types and modifications is presented.

Chalkley, Robert J.; Clauser, Karl R.

2012-01-01

370

Identification and interrogation of combinatorial histone modifications  

PubMed Central

Histone proteins are dynamically modified to mediate a variety of cellular processes including gene transcription, DNA damage repair, and apoptosis. Regulation of these processes occurs through the recruitment of non-histone proteins to chromatin by specific combinations of histone post-translational modifications (PTMs). Mass spectrometry has emerged as an essential tool to discover and quantify histone PTMs both within and between samples in an unbiased manner. Developments in mass spectrometry that allow for characterization of large histone peptides or intact protein has made it possible to determine which modifications occur simultaneously on a single histone polypeptide. A variety of techniques from biochemistry, biophysics, and chemical biology have been employed to determine the biological relevance of discovered combinatorial codes. This review first describes advancements in the field of mass spectrometry that have facilitated histone PTM analysis and then covers notable approaches to probe the biological relevance of these modifications in their nucleosomal context.

Karch, Kelly R.; DeNizio, Jamie E.; Black, Ben E.; Garcia, Benjamin A.

2013-01-01

371

SPH Modification Based on the Riemann Solver  

NASA Astrophysics Data System (ADS)

In this paper a modification of the Smooth Particle Hydrodynamics (SPH) method is considered. This modification allows increasing the accuracy of calculation of shocks and contact discontinuities in hydrodynamic flows. This paper also presents a research which shows the influence of different kernel forms used in the SPH simulations, and also the influence of particle parameter difference in distinct simulation domains. An example of a test one-dimensional Riemann problem is used to compare the computations by a «standard» SPH-method, by the A.N.Parshikov's method and also by a modified method presented in this paper. The comparison of the computation results with the exact solution in discrete analogs of the Chebyshev and L2 norms displays advantages of the offered modification.

Zubov, Anatoly D.; Lebedev, Alexander M.; Sokolovskaya, Valentina L.

2006-08-01

372

VDAC proteomics: post-translation modifications.  

PubMed

Voltage-dependent anion channels are abundant mitochondrial outer membrane proteins expressed in three isoforms, VDAC1-3, and are considered as "mitochondrial gatekeepers". Most tissues express all three isoforms. The functions of VDACs are several-fold, ranging from metabolite and energy exchange to apoptosis. Some of these functions depend on or are affected by interaction with other proteins in the cytosol and intermembrane space. Furthermore, the function of VDACs, as well as their interaction with other proteins, is affected by posttranslational modification, mainly phosphorylation. This review summarizes recent findings on posttranslational modification of VDACs and discusses the physiological outcome of these modifications. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism. PMID:22120575

Kerner, Janos; Lee, Kwangwon; Tandler, Bernard; Hoppel, Charles L

2012-06-01

373

Uncoupling Transcription from Covalent Histone Modification  

PubMed Central

It is widely accepted that transcriptional regulation of eukaryotic genes is intimately coupled to covalent modifications of the underlying chromatin template, and in certain cases the functional consequences of these modifications have been characterized. Here we present evidence that gene activation in the silent heterochromatin of the yeast Saccharomyces cerevisiae can occur in the context of little, if any, covalent histone modification. Using a SIR-regulated heat shock-inducible transgene, hsp82-2001, and a natural drug-inducible subtelomeric gene, YFR057w, as models we demonstrate that substantial transcriptional induction (>200-fold) can occur in the context of restricted histone loss and negligible levels of H3K4 trimethylation, H3K36 trimethylation and H3K79 dimethylation, modifications commonly linked to transcription initiation and elongation. Heterochromatic gene activation can also occur with minimal H3 and H4 lysine acetylation and without replacement of H2A with the transcription-linked variant H2A.Z. Importantly, absence of histone modification does not stem from reduced transcriptional output, since hsp82-?TATA, a euchromatic promoter mutant lacking a TATA box and with threefold lower induced transcription than heterochromatic hsp82-2001, is strongly hyperacetylated in response to heat shock. Consistent with negligible H3K79 dimethylation, dot1? cells lacking H3K79 methylase activity show unimpeded occupancy of RNA polymerase II within activated heterochromatic promoter and coding regions. Our results indicate that large increases in transcription can be observed in the virtual absence of histone modifications often thought necessary for gene activation.

Gross, David S.

2014-01-01

374

Applications for unique identifiers in the geological sciences  

NASA Astrophysics Data System (ADS)

Even though geology has always been a generalist discipline in many parts, approaches towards questions about Earth's past have become increasingly interdisciplinary. At the same time, a wealth of samples has been collected, the resulting data have been stored in in disciplinary databases, the interpretations published in scientific literature. In the past these resources have existed alongside each other, semantically linked only by the knowledge of the researcher and his peers. One of the main drivers towards the inception of the world wide web was the ability to link scientific sources over the internet. The Uniform Resource Locator (URL) used to locate resources on the web soon turned out to be ephemeral in nature. A more reliable way of addressing objects was needed, a way of persistent identification to make digital objects, or digital representations of objects, part of the record of science. With their high degree of centralisation the scientific publishing houses were quick to implement and adopt a system for unique and persistent identification, the Digital Object Identifier (DOI) ®. At the same time other identifier systems exist alongside DOI, e.g. URN, ARK, handle ®, and others. There many uses for persistent identification in science, other than the identification of journal articles. DOI are already used for the identification of data, thus making data citable. There are several initiatives to assign identifiers to authors and institutions to allow unique identification. A recent development is the application of persistent identifiers for geological samples. As most data in the geosciences are derived from samples, it is crucial to be able to uniquely identify the samples from which a set of data were derived. Incomplete documentation of samples in publications, use of ambiguous sample names are major obstacles for synthesis studies and re-use of data. Access to samples for re-analysis and re-appraisal is limited due to the lack of a central catalogue that allows finding a sample's archiving location. The International Geo Sample Number (IGSN) provides solutions to the questions of unique sample identification and discovery. Use of the IGSN in digital data systems allows building linkages between the digital representation of samples in sample registries, e.g. SESAR, and their related data in the literature and in web accessible digital data repositories. Persistent identifiers are now available for literature, data, samples, and authors. More applications, e.g. identification of methods or instruments, will follow. In conjunction with semantic web technology the application of unique and persistent identifiers in the geosciences will aid discovery both through systematic data mining, exploratory data analysis, and serendipity effects. This talk will discuss existing and emerging applications for persistent identifiers in the geological sciences.

Klump, J.; Lehnert, K. A.

2012-12-01

375

Epigenetic modifications in pediatric acute lymphoblastic leukemia.  

PubMed

Aberrant epigenetic modifications are well-recognized drivers for oncogenesis. Pediatric acute lymphoblastic leukemia (ALL) is no exception and serves as a model toward the significant impact these heritable alterations can have in leukemogenesis. In this brief review, we will focus on the main aspects of epigenetics, which control leukemogenesis in pediatric ALL, mainly DNA methylation, histone modification, and microRNA alterations. As we continue to gain better understanding of the driving mechanisms for pediatric ALL at both diagnosis and relapse, therapeutic interventions directed toward these pathways and mechanisms can be harnessed and introduced into clinical trials for pediatric ALL. PMID:24860797

Burke, Michael J; Bhatla, Teena

2014-01-01

376

Modification of gravity due to torsion  

SciTech Connect

Modifications of general relativity have been considered as one of the possible ways of addressing some of the outstanding problems related to the large scale gravitational physics. In this contribution we review some of the recent results which are due to the inclusion of dynamical torsion. More specifically we shall discuss the propagation of massive spin-2 particles in flat and curved space times. We shall show that, contrary to what is generally believed, spinning matter is not the sole source of torsion field. A symmetric energy momentum tensor can also couple to torsion degrees of freedom. The massive and massless spin-2 particles mix giving rise to an infrared modification of gravity.

Nair, V. P. [Physics Department, City College of the CUNY, New York, NY 10031 (United States); Nikiforova, V. [Physics Department, Mascow State University Moscow (Russian Federation); Randjbar-Daemi, S. [The Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Rubakov, V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation)

2010-01-01

377

Surface modification to prevent oxide scale spallation  

SciTech Connect

A surface modification to prevent oxide scale spallation is disclosed. The surface modification includes a ferritic stainless steel substrate having a modified surface. A cross-section of the modified surface exhibits a periodic morphology. The periodic morphology does not exceed a critical buckling length, which is equivalent to the length of a wave attribute observed in the cross section periodic morphology. The modified surface can be created using at least one of the following processes: shot peening, surface blasting and surface grinding. A coating can be applied to the modified surface.

Stephens, Elizabeth V; Sun, Xin; Liu, Wenning; Stevenson, Jeffry W; Surdoval, Wayne; Khaleel, Mohammad A

2013-07-16

378

Oxygen from Hydrogen Peroxide: An Experimental Modification  

NASA Astrophysics Data System (ADS)

A common experiment, performed at the high school and college levels, is the generation of a gas to explore molar mass and molar volume relationships. In one version of this experiment, hydrogen peroxide is decomposed by yeast to generate oxygen gas. This paper describes a simple modification to this experiment which eliminates the need for a pencil coated with petroleum jelly and dry yeast. This elimination not only prevents falling pieces of yeast from prematurely starting the reaction, but at the same time makes the reaction faster and simplifies cleanup. The modification also reduces the likelihood of cuts from broken tubing.

Burness, James H.

1996-09-01

379

Epigenetic Modifications in Pediatric Acute Lymphoblastic Leukemia  

PubMed Central

Aberrant epigenetic modifications are well-recognized drivers for oncogenesis. Pediatric acute lymphoblastic leukemia (ALL) is no exception and serves as a model toward the significant impact these heritable alterations can have in leukemogenesis. In this brief review, we will focus on the main aspects of epigenetics, which control leukemogenesis in pediatric ALL, mainly DNA methylation, histone modification, and microRNA alterations. As we continue to gain better understanding of the driving mechanisms for pediatric ALL at both diagnosis and relapse, therapeutic interventions directed toward these pathways and mechanisms can be harnessed and introduced into clinical trials for pediatric ALL.

Burke, Michael J.; Bhatla, Teena

2014-01-01

380

Meteorological satellites in support of weather modification  

NASA Technical Reports Server (NTRS)

During the past several years, many weather modification programs have been incorporating meteorological satellite data into both the operations and the analysis phase of these projects. This has occurred because of the advancement of the satellite as a mesoscale measurement platform, both temporally and spatially, and as the availability of high quality data has increased. This paper surveys the applications of meteorological satellite data to both summer and winter weather modification programs. A description of the types of observations needed by the programs is given, and an assessment of how accurately satellites can determine these necessary parameters is made.

Reynolds, D. W.; Vonder Haar, T. H.; Grant, L. O.

1978-01-01

381

Development and application of FI catalysts for olefin polymerization: unique catalysis and distinctive polymer formation.  

PubMed

Catalysts contribute to the efficient production of chemicals and materials in almost all processes in the chemical industry. The polyolefin industry is one prominent example of the importance of catalysts. The discovery of Ziegler-Natta catalysts in the 1950s resulted in the production of high-density polyethylenes (PEs) and isotactic polypropylenes (iPPs). Since then, further catalyst development has led to the production of a new series of polyolefins, including linear low-density PEs, amorphous ethylene/1-butene copolymers, ethylene/propylene/diene elastomers, and syndiotactic PPs (sPPs). Polyolefins are now the most important and the most produced synthetic polymers. This Account describes a family of next-generation olefin polymerization catalysts (FI catalysts) that are currently being used in the commercial production of value-added olefin-based materials. An FI catalyst is a heteroatom-coordinated early transition metal complex that combines a pair of nonsymmetric phenoxy-imine [O(-), N] chelating ligands with a group 4 transition metal. The catalytically active species derived from FI catalysts is highly electrophilic and can assume up to five isomeric structures based on the coordination of the phenoxy-imine ligand. In addition, the accessibility of the ligands of the FI catalysts and their amenability to modification offers an opportunity for the design of diverse catalytic structures. FI catalysts exhibit many unique chemical characteristics: precise control over chain transfers (including highly controlled living ethylene and propylene polymerizations), extremely high selectivity for ethylene, high functional group tolerance, MAO- and borate-free polymerization catalysis, significant morphology polymer formation, controlled multimodal behavior, high incorporation ability for higher alpha-olefins and norbornene, and highly syndiospecific and isospecific polymerizations of both propylene and styrene. These reactions also occur with very high catalyst efficiency. The reaction products include a wide variety of unique olefin-based materials, many of which were previously unavailable via other means of polymerization. We have produced selective vinyl- and Al-terminated PEs, ultrahigh molecular weight linear PEs, regio- and stereoirregular high molecular weight poly(higher alpha-olefin)s, ethylene- and propylene-based telechelic polymers, a wide array of polyolefinic block copolymers from ethylene, propylene, and higher alpha-olefins, and ultrafine noncoherent PE particles. FI catalysts are important from the organometallic, catalytic, and polymer science points of view, and the chemical industry is now using them for the production of value-added olefin-based materials. We anticipate that future research on FI catalysts will produce additional olefin-based materials with unique architectures and material properties and will offer scientists the chance to further study olefin polymerization catalysis and related reaction mechanisms. PMID:19588950

Makio, Haruyuki; Fujita, Terunori

2009-10-20

382

Epigenetic modifications in human spermatozoon and its potential role in embryonic development.  

PubMed

Spermatogenesis is a highly complex process involving mitotic cell division, meiosis and the process of spermiogenesis, during which unique and extensive chromatin and epigenetic modifications are remodeled to bring about specific epigenetic profiles for spermatozoa. Recent studies have shown that epigenetic modifications in mature spermatozoon play an important role in the developing embryo and its alterations in epigenetic patterns may increase the risk for fertilization failure, dysfunction of embryogenesis, preterm birth, low birthweight, congenital anomalies, perinatal mortality, and several other pregnancy-related complications seen at a higher frequency in babies conceived by in vitro fertilization (IVF). In this review, we assess the significance of epigenetic modifications (DNA methylation, histone retention and modification, RNAs and protamine) in mature spermatozoon and its potential role in embryonic development, and elucidate the relationship between altered epigenetic profile and associated diseases, providing basic information for preventing and treating male infertility, evaluating the epigenetic quality of sperm and reducing the risk of epigenetic diseases with babies conceived by assisted reproductive technology (ART). PMID:24846993

Shaoqin, Ge; Zhenghui, Zhao; Xueqian, Zhang; Yuan, Hao

2014-05-20

383

Heme-protein covalent bonds in peroxidases and resistance to heme modification during halide oxidation.  

PubMed

Plant peroxidases, as typified by horseradish peroxidase (HRP), primarily catalyze the one-electron oxidation of phenols and other low oxidation potential substrates. In contrast, the mammalian homologues such as lactoperoxidase (LPO) and myeloperoxidase primarily oxidize halides and pseudohalides to the corresponding hypohalides (e.g., Br(-) to HOBr, Cl(-) to HOCl). A further feature that distinguishes the mammalian from the plant and fungal enzymes is the presence of two or more covalent bonds between the heme and the protein only in the mammalian enzymes. The functional roles of these covalent links in mammalian peroxidases remain uncertain. We have previously reported that HRP can oxidize chloride and bromide ions, but during oxidation of these ions undergoes autocatalytic modification of its heme vinyl groups that virtually inactivates the enzyme. We report here that autocatalytic heme modification during halide oxidation is not unique to HRP but is a general feature of the oxidation of halide ions by fungal and plant peroxidases, as illustrated by studies with Arthromyces ramosus and soybean peroxidases. In contrast, LPO, a prototypical mammalian peroxidase, is protected from heme modification and its heme remains intact during the oxidation of halide ions. These results support the hypothesis that the covalent heme-protein links in the mammalian peroxidases protect the heme from modification during the oxidation of halide ions. PMID:16375846

Huang, Liusheng; Ortiz de Montellano, Paul R

2006-02-01

384

Prosthetic heme modification during halide ion oxidation. Demonstration of chloride oxidation by horseradish peroxidase.  

PubMed

Myeloperoxidase (MPO), eosinophil peroxidase (EPO), and chloroperoxidase can oxidize iodide, bromide, and chloride, but most peroxidases, including the prototypical horseradish peroxidase (HRP), reportedly only oxidize iodide and, in some cases, bromide. We report here that incubation of HRP with Br(-) and H(2)O(2) at acidic pH results in both bromination of monochlorodimedone and modification of the heme group. Mass spectrometry indicates that the heme 2- and 4-vinyl groups are modified by either replacement of a vinyl hydrogen by a bromide or addition of HOBr to give a bromohydrin. These reactions do not occur if protein-free heme and Br(-) are co-incubated with H(2)O(2) or if the HRP reaction is carried out at pH 7. Surprisingly, similar prosthetic heme modifications occur in incubations of HRP with H(2)O(2) and Cl(-). A mechanism is proposed involving oxidation of Br(-) or Cl(-) to give HOBr or HOCl, respectively, followed by addition to a vinyl group. In the reaction with Cl(-), a meso-chloro heme adduct is also formed. This first demonstration of Cl(-) oxidation by HRP, and the finding that prosthetic heme modification occurs when Br(-) or Cl(-) is oxidized in the absence of a cosubstrate, show that only modest tuning is required to achieve the unique chloride oxidation activity of MPO and EPO. The results raise the question of how the prosthetic hemes of MPO and EPO, whose function is to produce oxidized halide species, escape modification. PMID:15826172

Huang, Liusheng; Wojciechowski, Grzegorz; Ortiz de Montellano, Paul R

2005-04-20

385

BuD, a helix-loop-helix DNA-binding domain for genome modification.  

PubMed

DNA editing offers new possibilities in synthetic biology and biomedicine for modulation or modification of cellular functions to organisms. However, inaccuracy in this process may lead to genome damage. To address this important problem, a strategy allowing specific gene modification has been achieved through the addition, removal or exchange of DNA sequences using customized proteins and the endogenous DNA-repair machinery. Therefore, the engineering of specific protein-DNA interactions in protein scaffolds is key to providing `toolkits' for precise genome modification or regulation of gene expression. In a search for putative DNA-binding domains, BurrH, a protein that recognizes a 19?bp DNA target, was identified. Here, its apo and DNA-bound crystal structures are reported, revealing a central region containing 19 repeats of a helix-loop-helix modular domain (BurrH domain; BuD), which identifies the DNA target by a single residue-to-nucleotide code, thus facilitating its redesign for gene targeting. New DNA-binding specificities have been engineered in this template, showing that BuD-derived nucleases (BuDNs) induce high levels of gene targeting in a locus of the human haemoglobin ? (HBB) gene close to mutations responsible for sickle-cell anaemia. Hence, the unique combination of high efficiency and specificity of the BuD arrays can push forward diverse genome-modification approaches for cell or organism redesign, opening new avenues for gene editing. PMID:25004980

Stella, Stefano; Molina, Rafael; López-Méndez, Blanca; Juillerat, Alexandre; Bertonati, Claudia; Daboussi, Fayza; Campos-Olivas, Ramon; Duchateau, Phillippe; Montoya, Guillermo

2014-07-01

386

BuD, a helix-loop-helix DNA-binding domain for genome modification  

PubMed Central

DNA editing offers new possibilities in synthetic biology and biomedicine for modulation or modification of cellular functions to organisms. However, inaccuracy in this process may lead to genome damage. To address this important problem, a strategy allowing specific gene modification has been achieved through the addition, removal or exchange of DNA sequences using customized proteins and the endogenous DNA-repair machinery. Therefore, the engineering of specific protein–DNA interactions in protein scaffolds is key to providing ‘toolkits’ for precise genome modification or regulation of gene expression. In a search for putative DNA-binding domains, BurrH, a protein that recognizes a 19?bp DNA target, was identified. Here, its apo and DNA-bound crystal structures are reported, revealing a central region containing 19 repeats of a helix–loop–helix modular domain (BurrH domain; BuD), which identifies the DNA target by a single residue-to-nucleotide code, thus facilitating its redesign for gene targeting. New DNA-binding specificities have been engineered in this template, showing that BuD-derived nucleases (BuDNs) induce high levels of gene targeting in a locus of the human haemoglobin ? (HBB) gene close to mutations responsible for sickle-cell anaemia. Hence, the unique combination of high efficiency and specificity of the BuD arrays can push forward diverse genome-modification approaches for cell or organism redesign, opening new avenues for gene editing.

Stella, Stefano; Molina, Rafael; Lopez-Mendez, Blanca; Juillerat, Alexandre; Bertonati, Claudia; Daboussi, Fayza; Campos-Olivas, Ramon; Duchateau, Phillippe; Montoya, Guillermo

2014-01-01

387

NaxD is a deacetylase required for lipid A modification and Francisella pathogenesis  

PubMed Central

Summary Modification of specific Gram-negative bacterial cell envelope components, such as capsule, O-antigen and lipid A, are often essential for the successful establishment of infection. Francisella species express lipid A molecules with unique characteristics involved in circumventing host defences, which significantly contribute to their virulence. In this study, we show that NaxD, a member of the highly conserved YdjC superfamily, is a deacetylase required for an important modification of the outer membrane component lipid A in Francisella. Mass spectrometry analysis revealed that NaxD is essential for the modification of a lipid A phosphate with galactosamine in Francisella novicida, a model organism for the study of highly virulent Francisella tularensis. Significantly, enzymatic assays confirmed that this protein is necessary for deacetylation of its substrate. In addition, NaxD was involved in resistance to the antimicrobial peptide polymyxin B and critical for replication in macrophages and in vivo virulence. Importantly, this protein is also required for lipid A modification in F. tularensis as well as Bordetella bronchiseptica. Since NaxD homologues are conserved among many Gram-negative pathogens, this work has broad implications for our understanding of host subversion mechanisms of other virulent bacteria.

Llewellyn, Anna C.; Zhao, Jinshi; Song, Feng; Parvathareddy, Jyothi; Xu, Qian; Napier, Brooke A.; Laroui, Hamed; Merlin, Didier; Bina, James E.; Cotter, Peggy A.; Miller, Mark A.; Raetz, Christian R. H.; Weiss, David S.

2013-01-01

388

Surface modification of silicon-containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Surface modification of silicon-containing fluorocarbon (SiCF) films achieved by wet chemical treatments and through x-ray irradiation is examined. The SiCF films were prepared by plasma-enhanced chemical vapor deposition, using gas precursors of tetrafluoromethane and disilane. As-deposited SiCF film composition was analyzed by x-ray photoelectron spectroscopy. Surface modification of SiCF films utilizing n-lithiodiaminoethane wet chemical treatment is discussed. Sessile water-drop contact angle changed from 95°+/-2° before treatment to 32°+/-2° after treatment, indicating a change in the film surface characteristics from hydrophobic to hydrophilic. For x-ray irradiation on the SiCF film with a dose of 27.4 kJ/cm3, the contact angle of the sessile water drop changed from 95°+/-2° before radiation to 39°+/-3° after x-ray exposure. The effect of x-ray exposure on chemical bond structure of SiCF films is studied using Fourier transform infrared measurements. Electroless Cu deposition was performed to test the applicability of the surface modified films. The x-ray irradiation method offers a unique advantage in making possible surface modification in a localized area of high-aspect-ratio microstructures. Fabrication of a Ti-membrane x-ray mask is introduced here for selective surface modification using x-ray irradiation.

Jin, Yoonyoung; Desta, Yohannes; Goettert, Jost; Lee, G. S.; Ajmera, P. K.

2005-07-01

389

45 CFR 162.406 - Standard unique health identifier for health care providers.  

Code of Federal Regulations, 2010 CFR

...unique health identifier for health care providers. 162.406 Section 162...Unique Health Identifier for Health Care Providers § 162.406 Standard unique health identifier for health care providers. (a) Standard....

2010-10-01

390

45 CFR 162.406 - Standard unique health identifier for health care providers.  

Code of Federal Regulations, 2010 CFR

...Standard unique health identifier for health care providers. 162.406 Section...Standard Unique Health Identifier for Health Care Providers § 162.406 Standard unique health identifier for health care providers. (a)...

2009-10-01

391

45 CFR 162.406 - Standard unique health identifier for health care providers.  

Code of Federal Regulations, 2013 CFR

...Standard unique health identifier for health care providers. 162.406 Section...Standard Unique Health Identifier for Health Care Providers § 162.406 Standard unique health identifier for health care providers. (a)...

2013-10-01

392

Unique roles of acidic amino acids in phase transformation of calcium phosphates.  

PubMed

Although phase transformation is suggested as a key step in biomineralization, the chemical scenario about how organic molecules mediate inorganic phase transformations is still unclear. The inhibitory effect of amino acids on hydroxyapatite (HAP, the main inorganic component of biological hard tissues such as bone and enamel) formation was concluded by the previous biomimetic modeling based upon direct solution crystallization. Here we demonstrate that acidic amino acids, Asp and Glu, could promote HAP crystallization from its precursor crystal, brushite (DCPD). However, such a promotion effect could not be observed when the nonacidic amino acids were applied in the transformation-based HAP formation. We found that the specific modification of acidic amino acid on crystal-solution interfaces played a key role in the phase transition. The distinct properties between DCPD and HAP in the solution resulted in an interfacial energy barrier to suppress the spontaneous formation of HAP phase on DCPD phase. Different from the other amino acids, the carboxylate-rich amino acids, Asp and Glu, could modify the interfacial characteristics of these two calcium phosphate crystals to make them similar to each other. The experiments confirmed that the involvement of Asp or Glu reduced the interfacial energy barrier between DCPD and HAP, leading to a trigger effect on the phase transformation. An in-depth understanding about the unique roles of acidic amino acids may contribute to understanding phase transformation controls druing biomineralization. PMID:21190387

Chu, Xiaobin; Jiang, Wenge; Zhang, Zhisen; Yan, Yang; Pan, Haihua; Xu, Xurong; Tang, Ruikang

2011-02-10

393

Synthesis, characterisation and counterion dependent mesoscopic modifications of ionomer nanocomposites having different dimensional silver nanostructures  

NASA Astrophysics Data System (ADS)

Different dimensional silver nanostructures were synthesized in the cation exchange ionomer matrix Nafion-117 by varying temperature. The nanostructures formed were different sizes spherical nanoparticles depending upon the in situ reduction temperature. Mesoscopic architecture of the nanocomposite thin films containing different dimensional silver nanostructures has been studied by small angle x-ray scattering (SAXS) in different counterionic environment. Investigation of the modifications in nanostructure pattern along with modification in self-assembling morphology of the ionomer in metal-ionomer nanocomposites in different post reduction counterionic environment was found to be unique. The post reduction neutralization by different counterions having different degree of hydration resulted to reorganization of the embedded nanostructures along with the crystalline polymer backbone of the ionomer. This influenced the polydispersity of the nanostructures significantly.

Patra, Sabyasachi; Sen, Debasis; Agarwal, Chhavi; Pandey, Ashok K.; Mazumder, S.; Goswami, A.

2013-02-01

394

Wanted: unique names for unique atom positions. PDB-wide analysis of diastereotopic atom names of small molecules containing diphosphate  

PubMed Central

Background Biological chemistry is very stereospecific. Nonetheless, the diastereotopic oxygen atoms of diphosphate-containing molecules in the Protein Data Bank (PDB) are often given names that do not uniquely distinguish them from each other due to the lack of standardization. This issue has largely not been addressed by the protein structure community. Results Of 472 diastereotopic atom pairs studied from the PDB, 118 were found to have names that are not uniquely assigned. Among the molecules identified with these inconsistencies were many cofactors of enzymatic processes such as mononucleotides (e.g. ADP, ATP, GTP), dinucleotide cofactors (e.g. FAD, NAD), and coenzyme A. There were no overall trends in naming conventions, though ligand-specific trends were prominent. Conclusion The lack of standardized naming conventions for diastereotopic atoms of small molecules has left the ad hoc names assigned to many of these atoms non-unique, which may create problems in data-mining of the PDB. We suggest a naming convention to resolve this issue. The in-house software used in this study is available upon request. A version of the software used for the analyses described in this paper is available at our web site: .

Bottoms, Christopher A; Xu, Dong

2008-01-01

395

Modification of scuba regulator for IPPV.  

PubMed

Attention is appropriately being focused on the performance of adequate cardiopulmonary resuscitation in aquatic situations. We modified the second stage (mouthpiece) of a standard scuba regulator to permit intermittent positive pressure ventilation using either a mask or an esophageal obturator airway. Tests demonstrated the inexpensive modification to function adequately for emergency ventilation. PMID:3907085

Poulton, T J; Littleton, E K; Raudenbush, J

1985-06-01

396

Behavior Modification Techniques. I: Overcorrection. II: Punishment.  

ERIC Educational Resources Information Center

Two newsletters review the principles and application of two behavior modification techniques with mentally retarded persons: overcorrection and punishment. Overcorrection may be either restitutional, in which the client is made to restore the environment to a far better state than before the inappropriate behavior occurred, or positive practice…

Sovner, Robert, Ed.; Hurley, Anne Des Noyers, Ed.

1983-01-01

397

Adaptive size modification by dominant female meerkats.  

PubMed

In species of cooperative insects that live in large groups, selection for increased fecundity has led to the evolution of an increased body size among female reproductives, but whether this is also true of cooperative vertebrates is unknown. Among vertebrates, morphological modification of female breeders has only been documented in a single species; in naked mole rats (Heterocephalus glaber), acquisition of alpha status is associated with a significant increase in body size through an elongation of the lumbar vertebrae. Here we provide evidence of morphological modification among breeding females of a cooperative carnivore, the meerkat (Suricata suricatta), and demonstrate that this modification is likely to be adaptive. The same female meerkats were significantly larger when they were dominant than when they were subordinate. This increased body size was not explained by differences in age, foraging efficiency, or investment in offspring care, but may have arisen, in part, through increased levels of hormone that govern bone growth. Increases in body size are likely to result in fitness benefits, for large females delivered larger litters and had heavier offspring, both of which are known to correlate positively with measures of breeding success in meerkats. Our results suggest that the acquisition of alpha status in female meerkats is associated with an adaptive increase in body size and hence that morphological modification of female vertebrates may be more widespread than has been previously supposed. PMID:15341161

Russell, Andrew F; Carlson, Anne A; McIlrath, Grant M; Jordan, Neil R; Clutton-Brock, Tim

2004-07-01

398

Strategies for disease modification in Alzheimer's disease  

Microsoft Academic Search

Treating Alzheimer's disease (AD) is the biggest unmet medical need in neurology. Current drugs improve symptoms, but do not have profound disease-modifying effects. Three main classes of disease-modification approaches can be defined: one that is broadly neurotrophic or neuroprotective, one that targets specific aspects of AD pathology, and one that is based on epidemiological observation. This review discusses all three

Martin Citron

2004-01-01

399

25 CFR 134.7 - Modifications.  

Code of Federal Regulations, 2013 CFR

...ACTIVITIES PARTIAL PAYMENT CONSTRUCTION CHARGES ON INDIAN IRRIGATION PROJECTS § 134.7 Modifications. The act of July 1, 1932 (47 Stat. 564; 25 U.S.C. 386a), cancelled all irrigation assessments for construction costs against lands in Indian...

2013-04-01

400

Modification of cationic nanoclays with ionic liquids  

Microsoft Academic Search

As part of a broader effort to develop nanoclays functionalized with different heterocyclic aromatic structures for novel applications, preliminary data are reported on the modification of sodium montmorillonite, a cationic clay, with three low molecular weight pyridinium- and imidazolium-based ionic liquids. Commercially available unmodified clay was treated under different conditions with aqueous solutions of three ionic liquids: N-ethyl pyridinium tetrafluoroborate,

Neung Hyun Kim; Sanjay V. Malhotra; Marino Xanthos

2006-01-01

401

A Classroom Modification of the Ames Test.  

ERIC Educational Resources Information Center

A modification of the Ames test for detecting carcinogens and mutagens using a strain of bacteria is described. A suggestion is given for checking the correctness of procedures by using particular hair dyes which have been shown to be mutogenic. (Author/SA)

Yavornitzky, Joseph; Trzeciak, Victor

1979-01-01

402

A Logic Approach for LTL System Modification  

Microsoft Academic Search

Model checking has been successfully applied to system veri- fication. However, there are no standard and universal tools to date being applied for system modification. This paper introduces a formal approach called the Linear Temporal Logic (LTL) model update for system mod- ification. In contrast to previous error repairing methods, which were usually simple program debugging and specialized technical methods,

Yulin Ding; Yan Zhang

2005-01-01

403

D-21B RBCC Modification Feasibility Study  

NASA Technical Reports Server (NTRS)

This report presents a feasibility study on the modifications required to re-engine the Lockheed D-21 Drone for use as a NASA RBCC engine. An introduction, background information, engine configuration and performance, propulsion system integration, loads/thermal analysis, avionics/systems, flight test results, costs and work schedule, and some conclusions are presented.

1999-01-01

404

Albumin modification and fragmentation in renal disease.  

PubMed

Albumin is the most important antioxidant substance in plasma and performs many physiological functions. Furthermore, albumin is the major carrier of endogenous molecules and exogenous ligands. This paper reviews the importance of post-translational modifications of albumin and fragments thereof in patients with renal disease. First, current views and controversies on renal handling of proteins, mainly albumin, will be discussed. Post-translational modifications, namely the fragmentation of albumin found with proteomic techniques in nephrotic patients, diabetics, and ESRD patients will be presented and discussed. It is reasonable to hypothesize that proteolytic fragmentation of serum albumin is due to a higher susceptibility to proteases, induced by oxidative stress. The clinical relevance of the fragmentation of albumin has not yet been established. These modifications could affect some physiological functions of albumin and have a patho-physiological role in uremic syndrome. Proteomic analysis of serum allows the identification of over-expressed proteins and can detect post-translational modifications of serum proteins, hitherto hidden, using standard laboratory techniques. PMID:22120732

Donadio, Carlo; Tognotti, Danika; Donadio, Elena

2012-02-18

405

Microscale surface modifications for heat transfer enhancement.  

PubMed

In this experimental study, two surface modification techniques were investigated for their effect on heat transfer enhancement. One of the methods employed the particle (grit) blasting to create microscale indentations, while the other used plasma spray coating to create microscale protrusions on Al 6061 (aluminum alloy 6061) samples. The test surfaces were characterized using scanning electron microscopy (SEM) and confocal scanning laser microscopy. Because of the surface modifications, the actual surface area was increased up to 2.8× compared to the projected base area, and the arithmetic mean roughness value (Ra) was determined to vary from 0.3 ?m for the reference smooth surface to 19.5 ?m for the modified surfaces. Selected samples with modified surfaces along with the reference smooth surface were then evaluated for their heat transfer performance in spray cooling tests. The cooling system had vapor-atomizing nozzles and used anhydrous ammonia as the coolant in order to achieve heat fluxes up to 500 W/cm(2) representing a thermal management setting for high power systems. Experimental results showed that the microscale surface modifications enhanced heat transfer coefficients up to 76% at 500 W/cm(2) compared to the smooth surface and demonstrated the benefits of these practical surface modification techniques to enhance two-phase heat transfer process. PMID:24003985

Bostanci, Huseyin; Singh, Virendra; Kizito, John P; Rini, Daniel P; Seal, Sudipta; Chow, Louis C

2013-10-01

406

Peroxynitrite-mediated oxidative protein modifications  

Microsoft Academic Search

Proteins are targets of reactive species and detection of oxidatively modified proteins is often used as an index of oxidative stress. Peroxynitrite is a strong oxidant formed by reaction of nitric oxide with superoxide. Using fatty acid-free bovine serum albumin as a model we examined peroxynitrite-mediated protein modifications. The reaction of protein with peroxynitrite resulted in the oxidation of tryptophan

Harry Ischiropoulos; Abu B. Al-Mehdi

1995-01-01

407

A Suggested Modification to Maslow's Need Hierarchy  

ERIC Educational Resources Information Center

Since its development, Maslow's need hierarchy has been criticized and applauded. This investigation was undertaken to explore a modification of the upper levels of the need hierarchy based upon the application of power, competition, and achievement to self, as well as the concept of "other directed." (Author)

Groves, David L.; And Others

1975-01-01

408

Modification of hypoeutectic Al-Si alloys  

Microsoft Academic Search

Modification of the Al-Si eutectic microstructure has been studied by using the entrained droplet technique in a range of hypoeutectic Al-Si alloys doped with different levels of phosphorus and sodium. Differential scanning calorimetry has been used to investigate the kinetics of silicon nucleation during eutectic solidification, and transmission and scanning transmission electron microscopy has been used to investigate the eutectic

C. R. Ho; B. Cantor

1995-01-01

409

Advances in PSII techniques for surface modification  

Microsoft Academic Search

Recent activities in plasma source ion implantation (PSII) technology include scale-up demonstrations for industry and development of variations on the original PSII concept for surface modification. This paper presents an overview of the continued growth of PSII research facilities world-wide and the industrial demonstrations within the USA. In order to expand the applicability of PSII, Los Alamos is actively researching

K. C Walter; M Nastasi; N. P Baker; C. P Munson; W. K Scarborough; J. T Scheuer; B. P Wood; J. R Conrad; K Sridharan; S Malik; R. A Bruen

1998-01-01

410

APPLICATION OF COMBUSTION MODIFICATIONS OF INDUSTRIAL EQUIPMENT  

EPA Science Inventory

The report gives results of a field test program to evaluate the effect of minor combustion modifications on pollutant emissions from a variety of industrial combustion equipment types. Tested were 22 units, including refinery process heaters; clay and cement kilns; steel and alu...

411

Prespective from a weather modification experiment  

Microsoft Academic Search

This article provides some views on the statistical design and analysis of weather modification experiments. Perspectives were developed from experience with analyses of the Santa Barbara Phase I experiment summarized in Section 2, Randomization analvses are reported and compared with previously published parametric analyses. The parametric significance levels of tests for a cloud seeding effect agree well with the significance

Ralph A. Bradley; Elton Scott

1980-01-01

412

Using global unique identifiers to link autism collections  

PubMed Central

Objective To propose a centralized method for generating global unique identifiers to link collections of research data and specimens. Design The work is a collaboration between the Simons Foundation Autism Research Initiative and the National Database for Autism Research. The system is implemented as a web service: an investigator inputs identifying information about a participant into a client application and sends encrypted information to a server application, which returns a generated global unique identifier. The authors evaluated the system using a volume test of one million simulated individuals and a field test on 2000 families (over 8000 individual participants) in an autism study. Measurements Inverse probability of hash codes; rate of false identity of two individuals; rate of false split of single individual; percentage of subjects for which identifying information could be collected; percentage of hash codes generated successfully. Results Large-volume simulation generated no false splits or false identity. Field testing in the Simons Foundation Autism Research Initiative Simplex Collection produced identifiers for 96% of children in the study and 77% of parents. On average, four out of five hash codes per subject were generated perfectly (only one perfect hash is required for subsequent matching). Discussion The system must achieve balance among the competing goals of distinguishing individuals, collecting accurate information for matching, and protecting confidentiality. Considerable effort is required to obtain approval from institutional review boards, obtain consent from participants, and to achieve compliance from sites during a multicenter study. Conclusion Generic unique identifiers have the potential to link collections of research data, augment the amount and types of data available for individuals, support detection of overlap between collections, and facilitate replication of research findings.

Whitney, Glen; McAuliffe, Matthew; Wang, Hailong; McCreedy, Evan; Rozenblit, Leon; Evans, Clark C

2010-01-01

413

New facility for ion beam materials characterization and modification at Los Alamos  

NASA Astrophysics Data System (ADS)

The Ion Beam Materials Laboratory (IBML) is a new Los Alamos laboratory devoted to the characterization and modification of the near surfaces of materials. The primary instruments of the IBML are a tandem electrostatic accelerator, a National Electrostatic Corp. model 9SDH, coupled with a Varian CF-3000 ion implanter. The unique organizational structure of the IBML as well as the operational characteristics of the 9SDH (after approximately 3000 h of operation) and the laboratories' research capabilities will be discussed. Examples of current research results will also be presented.

Tesmer, J. R.; Maggiore, C. J.; Parkin, D. M.

1989-04-01

414

An Hsp90 modulator that exhibits a unique mechanistic profile  

PubMed Central

Described is the synthesis of two biotinylated derivatives of a cytotoxic macrocycle. Pull-down assays indicate that this macrocycle targets the N-middle domain of Hsp90. Untagged compound can effectively compete away tagged compound-Hsp90 protein complexes, confirming the binding specificity of the macrocycle for Hsp90. The macrocycle is similar in potency to other structurally-related analogs of Sansalvamide A (San A) and induces apoptosis via a caspase 3 mechanism. Unlike other San A derivatives, we show that the macrocycle does not inhibit binding between C-terminal client proteins and co-chaperones and Hsp90, suggesting that it has a unique mechanism of action.

Ramsey, Deborah M.; McConnell, Jeanette R.; Alexander, Leslie D.; Tanaka, Kaishin W.; Vera, Chester M.; McAlpine, Shelli R.

2012-01-01

415

Explaining human uniqueness: genome interactions with environment, behaviour and culture  

PubMed Central

What makes us human? Specialists in each discipline respond through the lens of their own expertise. In fact, ‘anthropogeny’ (explaining the origin of humans) requires a transdisciplinary approach that eschews such barriers. Here we take a genomic and genetic perspective towards molecular variation, explore systems analysis of gene expression and discuss an organ-systems approach. Rejecting any ‘genes versus environment’ dichotomy, we then consider genome interactions with environment, behaviour and culture, finally speculating that aspects of human uniqueness arose because of a primate evolutionary trend towards increasing and irreversible dependence on learned behaviours and culture — perhaps relaxing allowable thresholds for large-scale genomic diversity.

Varki, Ajit; Geschwind, Daniel H.; Eichler, Evan E.

2009-01-01

416

Unique and overlapping pollutant stress proteins of Escherichia coli  

SciTech Connect

Exposure of growing batch cultures of Escherichia coli to nine different model micropollutants' (benzene, cadmium chloride, chlorpyrivos, 2,4-dichloroaniline, dioctylphthalate, hexachlorobenzene, pentachlorophenol, trichloroethylene, and tetrapropylbenzosulfonate) led to the induction of 13 to 39 proteins, as analyzed by two-dimensional gel electrophoresis. Some of these proteins overlapped with heat shock and carbon starvation proteins, but at least 50% were unique to a given chemical. The stress protein induction showed a temporal pattern, indicating sequential gene expression. Chemical stress protein synthesis occurred even at concentrations that had no effect on growth. Thus, the synthesis of these proteins can be a sensitive index of stress and the nature of environmental pollution.

Blom, A.; Harder, W. (TNO Inst. of Environmental Sciences, Delft (Netherlands)); Matin, A. (Stanford Univ., CA (United States))

1992-01-01

417

Unique determination of model coronal magnetic fields using photospheric observations  

NASA Technical Reports Server (NTRS)

We show that the nonradial field-boundary condition (or the line-of-sight boundary condition) for the Laplacian-like equation developed by Bogdan and Low (1986) is sufficient to uniquely determine the model coronal magnetic field provided the electric currents are horizontal (or zero, the current-free case) at the solar surface as well as in the solar atmosphere between the photosphere and the source surface. The derived recursion formulae for the spherical harmonic coefficients can be used to determine the spherical harmonic coefficients in the solutions of the horizontal current models very efficiently.

Zhao, Xuepu; Hoeksema, J. T.

1993-01-01

418

A unique exercise facility for simulating orbital extravehicular activity  

NASA Astrophysics Data System (ADS)

A unique exercise facility has been developed and used to simulate orbital extravehicular activity (EVA). The device incorporates an arm ergometer into a mechanism which places the subject in the zero-g neutral body posture. The intent of this configuration is to elicit muscular, cardiovascular, respiratory, and thermoregulatory responses similar to those observed during orbital EVA. Experiments done with this facility will help characterize the astronaut's dynamic heat balance during EVA and will eventually lead to the development of an automated thermal control system which would more effectively maintain thermal comfort.

Williamson, Rebecca C.; Sharer, Peter J.; Webbon, Bruce W.

419

Encoding unique global minima in nested neural networks  

NASA Technical Reports Server (NTRS)

Nested neural networks are constructed from outer products of patterns over (-1,0,1)N, whose nonzero bits define subnetworks and the subcodes stored in them. The set of permissible words, which are network-size binary patterns composed of subcode words that agree in their common bits, is characterized, and their number is derived. It is shown that if the bitwise products of the subcode words are linearly independent, the permissible words are the unique global minima of the Hamiltonian associated with the network.

Baram, Yoram

1991-01-01

420

A unique approach to fixed occipito-cervico-thoracic deformity.  

PubMed

We discuss a unique approach to a patient who presented with severe kyphosis and laterolisthesis of the cranio-cervico-thoracic spine, following a history of neck trauma 24months prior to presentation. The patient had organized voluntary euthanasia if no treatment could be performed. Our approach included a three-part procedure over a 3-week time interval, including: initial traction, division of anterior neck muscles, multilevel anterior fusion and, finally, posterior occipito-cervico-thoracic fusion. Follow-up at 6months revealed a patient in neutral sagittal and coronal balance of the neck. PMID:23313528

Aw, G E; Mobbs, R J

2013-04-01

421

On small uniquely vertex-colourable graphs and Xu's conjecture  

Microsoft Academic Search

Consider the parameter ?(G)=|E(G)|?|V(G)|(k?1)+(k2) for a k-chromatic graph G, on the set of vertices V(G) and with the set of edges E(G). It is known that ?(G)?0 for any k-chromatic uniquely vertex-colourable graph G (k-UCG), and, S.J. Xu has conjectured that for any k-UCG, G,?(G)=0 implies that cl(G)=k; in which cl(G) is the clique number of G. In this paper,

Amir Daneshgar; Reza Naserasr

2000-01-01

422

Unique case of a geminated supernumerary tooth with trifid crown  

PubMed Central

Gemination, a relatively uncommon dental anomaly, is characterized by its peculiar representation as a tooth with a bifid crown and a common root and root canal. It usually occurs in primary dentition. To come across gemination in a supernumerary tooth is a rare phenomenon. The purpose of this paper is to present a unique case of hyperdontia wherein gemination in an impacted supernumerary tooth resulted in a trifid crown unlike the usual bifid crown. The role of conventional radiographs as well as computed tomography, to accurately determine the morphology and spatial location, and to arrive at a diagnosis, is also emphasized in this paper.

Ather, Hunaiza; Sheth, Sanket Milan; Muliya, Vidya Saraswathi

2012-01-01

423

The unique sound of the Uni-Vibe pedal  

NASA Astrophysics Data System (ADS)

A short paper covering optics and music: the Uni-Vibe, which is responsible for the unique sound of Hendrix' Woodstock performance, is one of many phasing devices based on photo conductive cells used as variable resistors. However, its sound is well distinguishable from other phasers. In the paper we shall discuss the basic properties and try to qualify and quantify the effect on the spectra of certain chords. The present paper is a side effect of the musical interests of the authors and is triggered by the announcement of the Novel Systems Session including the topics 'Optics and Music' and Historical Devices.

Hahlweg, Cornelius; Rothe, Hendrik

2012-10-01

424

THE HAYLOFT OF THE JENNE BARN, SHOWING ITS UNIQUE CONSTRUCTION. ...  

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

THE HAYLOFT OF THE JENNE BARN, SHOWING ITS UNIQUE CONSTRUCTION. (The barn?s gambrel roof is supported by seven bents made-up of diagonal stilts, collar beams, and cross-bracing that tie into the support columns on the ground floor and the sill plates. Also visible are the cables installed across each bent in 2000-02 to reinforce the construction, the hay door at the gable end, and the ladder and opening accessing the barn?s ground floor.) - Jenne Farm, Barn, 538 Engle Road, Coupeville, Island County, WA

425

Molecular design of dinotefuran with unique insecticidal properties.  

PubMed

Dinotefuran, (RS)-1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine, is a neonicotinoid insecticide developed by Mitsui Chemicals Agro. Dinotefuran provides a tetrahydrofuran (THF) moiety distinct from other neonicotinoids with a chloropyridine or chlorothiazole ring, which is considered to be an essential structural element for the neonicotinoid action. The molecular design strategy based on acetylcholine ester moiety as a lead structure has successfully led to the discovery of dinotefuran with the cyclic ether THF functional group. The unique chemical and excellent biological properties and favorable toxicological profile make dinotefuran available for pest management in wide range of crops with a variety of application methods. PMID:20919736

Wakita, Takeo

2011-04-13

426

Space Station Freedom: a unique laboratory for gravitational biology research  

NASA Technical Reports Server (NTRS)

The advent of Space Station Freedom (SSF) will provide a permanent laboratory in space with unparalleled opportunities to perform biological research. As with any spacecraft there will also be limitations. It is our intent to describe this space laboratory and present a picture of how scientists will conduct research in this unique environment we call space. SSF is an international venture which will continue to serve as a model for other peaceful international efforts. It is hoped that as the human race moves out from this planet back to the moon and then on to Mars that SSF can serve as a successful example of how things can and should be done.

Phillips, R. W.; Cowing, K. L.

1993-01-01

427

Unique mechanism of chance fracture in a young adult male.  

PubMed

Since the first description of the Chance fracture in 1948, there have been few case reports of unique mechanisms causing this classical flexion-extension injury to the spine in motor vehicle accidents, sports injury, and falls. To our knowledge, this injury has not been reported from a fall with the mechanistic forces acting laterally on the spine and with spinal support in place. We present a 21-year-old male who slid down a flight of stairs onto his side wearing a heavy mountaineering style backpack, subsequently sustaining a Chance fracture of his first lumbar vertebrae. PMID:23599852

Birch, Aaron; Walsh, Ryan; Devita, Diane

2013-03-01

428

A Unique Dermoscopy Pattern of Solitary Cutaneous Reticulohistiocytosis  

PubMed Central

Histiocytosis represents a group of rare disorders characterized by nonneoplastic proliferation of histiocytes and solitary cutaneous reticulohistiocytosis (SCR) is a form of non-Langerhans histiocytosis. SCR consists of small papule, usually single, varying in color from yellow to brownish-red, more frequent in young adults, and uncommon in childhood. We report a case of SCR in an 11-year-old child and emphasize a unique dermoscopy pattern of this lesion and its correlation with clinical and histopathological aspects in the diagnosis.

Nogueira, Letycia Lopes Chagas; Chaves, Gabriel Monteiro de Castro; Muniz, Mariana Daflon Vinhosa; Timbo, Renata Pinto Fernandes; Sasse, Mariana Martins; Meotti, Carolina Degen

2013-01-01

429

A unique exercise facility for simulating orbital extravehicular activity  

NASA Technical Reports Server (NTRS)

A unique exercise facility has been developed and used to simulate orbital extravehicular activity (EVA). The device incorporates an arm ergometer into a mechanism which places the subject in the zero-g neutral body posture. The intent of this configuration is to elicit muscular, cardiovascular, respiratory, and thermoregulatory responses similar to those observed during orbital EVA. Experiments done with this facility will help characterize the astronaut's dynamic heat balance during EVA and will eventually lead to the development of an automated thermal control system which would more effectively maintain thermal comfort.

Williamson, Rebecca C.; Sharer, Peter J.; Webbon, Bruce W.

1993-01-01

430

Cryogenic wind tunnels: Unique capabilities for the aerodynamicist  

NASA Technical Reports Server (NTRS)

The cryogenic wind-tunnel concept as a practical means for improving ground simulation of transonic flight conditions. The Langley 1/3-meter transonic cryogenic tunnel is operational, and the design of a cryogenic National Transonic Facility is undertaken. A review of some of the unique capabilities of cryogenic wind tunnels is presented. In particular, the advantages of having independent control of tunnel Mach number, total pressure, and total temperature are highlighted. This separate control over the three tunnel parameters will open new frontiers in Mach number, Reynolds number, aeroelastic, and model-tunnel interaction studies.

Hall, R. M.

1976-01-01

431

Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains  

PubMed Central

Susceptibility to 41 antimicrobials was studied with 99 Stenotrophomonas maltophilia strains, and different pulsed-field gel electrophoresis profiles were identified among 130 prospectively collected isolates. Moxalactam, doxycycline, minocycline, and clinafloxacin displayed the highest activity (?98% susceptibility). Ticarcillin resistance (75%) was reverted by clavulanate in 25% of strains. Trimethoprim-sulfamethoxazole resistance was 26.2% (?4 [trimethoprim]/76 [sulfamethoxazole] ?g/ml) and dropped to 11.1% when an 8/152-?g/ml breakpoint was applied based on its bimodal MIC distribution. Resistance was lower when unique strains were considered, because clonal organisms contribute to resistance.

Valdezate, Sylvia; Vindel, Ana; Loza, Elena; Baquero, Fernando; Canton, Rafael

2001-01-01

432

Antimicrobial susceptibilities of unique Stenotrophomonas maltophilia clinical strains.  

PubMed

Susceptibility to 41 antimicrobials was studied with 99 Stenotrophomonas maltophilia strains, and different pulsed-field gel electrophoresis profiles were identified among 130 prospectively collected isolates. Moxalactam, doxycycline, minocycline, and clinafloxacin displayed the highest activity (> or = 98% susceptibility). Ticarcillin resistance (75%) was reverted by clavulanate in 25% of strains. Trimethoprim-sulfamethoxazole resistance was 26.2% (> or = 4 [trimethoprim]/76 [sulfamethoxazole] microg/ml) and dropped to 11.1% when an 8/152-microg/ml breakpoint was applied based on its bimodal MIC distribution. Resistance was lower when unique strains were considered, because clonal organisms contribute to resistance. PMID:11302834

Valdezate, S; Vindel, A; Loza, E; Baquero, F; Cantón, R

2001-05-01

433

Eubacterial rhodopsins - unique photosensors and diverse ion pumps.  

PubMed

Since the discovery of proteorhodopsins, the ubiquitous marine light-driven proton pumps of eubacteria, a large number of other eubacterial rhodopsins with diverse structures and functions have been characterized. Here, we review the body of knowledge accumulated on the four major groups of eubacterial rhodopsins, with the focus on their biophysical characterization. We discuss advances and controversies on the unique eubacterial sensory rhodopsins (as represented by Anabaena sensory rhodopsin), proton-pumping proteorhodopsins and xanthorhodopsins, as well as novel non-proton ion pumps. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks. PMID:23748216

Brown, Leonid S

2014-05-01

434

GRAIL: A unique mediator of CD4 T lymphocyte unresponsiveness  

PubMed Central

GRAIL (gene related to anergy in lymphocytes, also known as RNF128), an ubiquitin-protein ligase (E3), utilizes a unique single transmembrane protein with a split function motif, and is an important gatekeeper of T cell unresponsiveness. While it may play a role in other CD4 T cell functions including activation, survival, and differentiation, GRAIL is most well characterized as a negative regulator of TCR responsiveness and cytokine production. Here, we review the recent literature on this remarkable E3 in the regulation of human and mouse CD4 T cell unresponsiveness.

Whiting, Chan C.; Su, Leon L.; Lin, Jack T.; Fathman, C. Garrison

2010-01-01

435

Apparatus for controlling system state based on unique identifiers  

DOEpatents

An apparatus allows workers to assert and release control over the energization of a system. The apparatus does not require the workers to carry any additional paraphernalia, and is not be easily defeated by other workers. Users asserting and releasing control present tokens uniquely identifying each user to a reader, and the apparatus prevents transition of the system to an undesired state until an appropriate number of users are currently asserting control. For example, a dangerous manufacturing robot can be prevented from energizing until all the users that have asserted control when entering the robot's controlled space have subsequently released control when leaving the robot's controlled space.

Drotning, William D. (Albuquerque, NM)

2002-01-01

436

Modifications and integration of the electronic tracking board in a pediatric emergency department.  

PubMed

Electronic health records (EHRs) are used for data storage; provider, laboratory, and patient communication; clinical decision support; procedure and medication orders; and decision support alerts. Clinical decision support is part of any EHR and is designed to help providers make better decisions. The emergency department (ED) poses a unique environment to the use of EHRs and clinical decision support. Used effectively, computerized tracking boards can help improve flow, communication, and the dissemination of pertinent visit information between providers and other departments in a busy ED. We discuss the unique modifications and decisions made in the implementation of an EHR and computerized tracking board in a pediatric ED. We discuss the changing views based on provider roles, customization to the user interface including the layout and colors, decision support, tracking board best practices collected from other institutions and colleagues, and a case study of using reminders on the electronic tracking board to drive pain reassessments. PMID:23823269

Dexheimer, Judith W; Kennebeck, Stephanie

2013-07-01

437

Surface Modification of Nanoclays by Catalytically Active Transition Metal Ions  

SciTech Connect

A unique class of nanoclays was prepared by modification of pristine clays or organoclays (Cloisite C20A) with transition metal ions (TMIs). The composition, structure, morphology and thermal properties of TMI-modified nanoclays were investigated by atomic absorption spectroscopy (AAS), elemental analysis (EA), scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray absorption near-edge structure (XANES) spectroscopy. The content of TMIs in modified clays was found to be close to the limiting value of ion exchange capacity. SEM and X-ray results confirmed that TMIs were located between the mineral layers instead of being adsorbed on the surface of clay particles. TGA results indicated that the TMI treatment of organoclays could significantly increase the thermal stability, which was more pronounced in air than in nitrogen. Temperature-resolved SAXS measurements revealed that the presence of TMIs increased the onset temperature of structural degradation. The higher thermal stability of TMI-modified organoclays can be attributed to the change in the thermal degradation mechanism, resulting in a decrease in the yield of volatile products and the formation of char facilitated by the presence of catalytically active TMIs.

Nawani,P.; Gelfer, M.; Hsiao, B.; Frenkel, A.; Gilman, J.; Khalid, S.

2007-01-01

438

Modification of Molecular Spin Crossover in Ultra-Thin Films  

NASA Astrophysics Data System (ADS)

Iron (II) spin crossover compounds exhibit a strong connection between molecular spin state and electronic structure that make them exciting candidates for highly tunable materials for spintronic applications. The spin crossover phenomenon is often extremely sensitive to crystal packing effects that may be modified in device environments compared to bulk materials. We report evidence for dramatic modification of spin crossover in bilayer films of Fe[(H2Bpz2)2bpy] on Au(111) compared to bulk behavior. Scanning Tunneling Microscopy, spectroscopy, and local conductance mapping show spin-state coexistence in bilayer films of Fe[(H2Bpz2)2bpy] on Au(111) that is independent of temperature between 130 K and 300 K due to the unique packing constraints of the bilayer film that promote deviations from bulk behavior. Local density of states measured for different spin states show that high-spin molecules have a smaller transport gap than low-spin molecules in agreement with density functional theory calculations. In addition, aggregation of spin states into ``like-spin'' domains is observed.

Dougherty, Daniel; Pronschinske, Alex; Chen, Yifeng; Calzolari, Arrigo; Lewis, Geoff; Shultz, David; Buongiorno-Nardelli, Marco

2013-03-01

439

The Mossy Fiber Bouton: the "Common" or the "Unique" Synapse?  

PubMed Central

Synapses are the key elements for signal processing and plasticity in the brain. They are composed of nearly the same structural subelements, an apposition zone including a pre- and postsynaptic density, a cleft and a pool of vesicles. It is, however, their actual composition that determines their different behavior in synaptic transmission and plasticity. Here, we describe and discuss the structural factors underlying the unique functional properties of the hippocampal mossy fiber (MF) synapse. Two membrane specializations, active zones (AZs; transmitter release sites), and puncta adherentia (PA), putative adhesion complexes were found. On average, individual boutons had ?20 AZs with a mean surface area of 0.1??m2 and a short distance of 0.45??m between individual AZs. Mossy fiber boutons (MFBs) and their target structures were isolated from each other by astrocytes, but fine glial processes never reached the AZs. Therefore, two structural factors are likely to promote synaptic cross-talk: the short distance and the absence of fine glial processes between individual AZs. Thus, synaptic crosstalk may contribute to the high efficacy of hippocampal MF synapses. On average, an adult bouton contained ?16,000 synaptic vesicles; ?600 vesicles were located within 60?nm from the AZ, ?4000 between 60?nm and 200?nm, and the remaining beyond 200?nm, suggesting large readily releasable, recycling, and reserve pools. Thus, the size of the three pools together with the number and distribution of AZs underlie the unique extent of synaptic efficacy and plasticity of the hippocampal MF synapse.

Rollenhagen, Astrid; Lubke, Joachim H. R.

2010-01-01

440

Unique phytochrome responses of the holoparasitic plant Orobanche minor.  

PubMed

Holoparasitic plants such as Orobanche spp. have lost their photosynthetic ability, so photoresponses to optimize photosynthesis are not necessary in these plants. Photoresponses are also involved in the regulation of plant development but the photoresponses of holoparasites have not been characterized in detail. In this study, the phytochrome (phy)-related photoresponse of Orobanche minor was investigated. Its photoreceptor, phytochrome A (OmphyA), was also characterized. Light effects on germination, shoot elongation, anthocyanin biosynthesis, and OmphyA expression and subcellular localization were analyzed. Red light (R):far-red light (FR) reversible inhibition of O. minor seed germination demonstrated that phy-mediated responses are retained in this holoparasite. Shoot elongation was inhibited by FR but not by R. This pattern is unique among known patterns of plant photoresponses. Additionally, molecular analysis showed that OmphyA is able to respond to the light signals. Interestingly, the unique pattern of photoresponses in O. minor seems to have been modified for adaptation to its parasitic life cycle. We hypothesize that this alteration has resulted from the loss or alteration of some phy-signaling components. Elucidation of altered components in phy signaling in this parasite will provide useful information not only about its physiological characteristics but also about general plant photoreception systems. PMID:19323792

Takagi, Kazuteru; Okazawa, Atsushi; Wada, Yu; Mongkolchaiyaphruek, Anchaya; Fukusaki, Eiichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

2009-06-01

441

Unique Features and Spacecraft Applications of Dynamic Isotope Power Systems  

SciTech Connect

The dynamic isotope power system represents the most recent attempt to develop a heat-engine generator for space electric power. A major objective in this most recent effort was to increase the power and to reduce the cost of nuclear space power systems to the point where the unique features of this power source could be brought to bear for Earth-orbit missions which could benefit therefrom. This objective was largely achieved; both weight and cost of the dynamic isotope systems are comparable to solar power systems. The dynamic isotope power system, designed for spacecraft requiring prime power in the 500-2000 W range, has been successfully built and ground tested. A number of studies, summarized herein, have demonstrated the advantages of using such a power system instead of the conventional solar system for a variety of Earth-orbit missions. These advantages stem from the unique nature of the dynamic isotope system, different in kind from solar power systems. As a result, in many cases, the spacecraft design can be significantly simplified and more closely harmonized with mission requirements. This overall advantage can be crucial in missions which have stringent pointing, stability, viewing, and/or positioning requirements.

Raab, B.

1982-01-01

442

Unique determination of solutions to the Burnett equations  

NASA Technical Reports Server (NTRS)

Recent success in applying the Burnett equations to the one-dimensional shock-structure problem has raised the issue of whether the full Burnett equations can be used replace the Navier-Stokes equations for solving boundary-value problems in rarefied gasdynamics. As is familiar from the classical rarefied gasdynamics literature, the Burnett equations, if not solved as a successive approximation to the Navier-Stokes equations for a small Knudsen number, would require more boundary conditions than those in the Navier-Stokes system, owing to the presence of the higher-order derivatives. In this paper, this issue is examined with concrete solution examples for the steady Couette flows, addressing specifically whether solutions to the full Burnett equations can be uniquely determined without adding more boundary conditions than those in the Navier-Stokes system. The analysis, supported by detailed numerical solutions, confirms that additional boundary conditions are needed as long as the Knudsen number is not identically zero, lest the solution to the Burnett equations is not unique.

Lee, C. J.

1994-01-01

443

Rationality, irrationality and escalating behavior in lowest unique bid auctions.  

PubMed

Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions--lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of "bid space". The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets. PMID:22279553

Radicchi, Filippo; Baronchelli, Andrea; Amaral, Luís A N

2012-01-01

444

Unique sodium phosphosilicate glasses designed through extended topological constraint theory.  

PubMed

Sodium phosphosilicate glasses exhibit unique properties with mixed network formers, and have various potential applications. However, proper understanding on the network structures and property-oriented methodology based on compositional changes are lacking. In this study, we have developed an extended topological constraint theory and applied it successfully to analyze the composition dependence of glass transition temperature (Tg) and hardness of sodium phosphosilicate glasses. It was found that the hardness and Tg of glasses do not always increase with the content of SiO2, and there exist maximum hardness and Tg at a certain content of SiO2. In particular, a unique glass (20Na2O-17SiO2-63P2O5) exhibits a low glass transition temperature (589 K) but still has relatively high hardness (4.42 GPa) mainly due to the high fraction of highly coordinated network former Si((6)). Because of its convenient forming and manufacturing, such kind of phosphosilicate glasses has a lot of valuable applications in optical fibers, optical amplifiers, biomaterials, and fuel cells. Also, such methodology can be applied to other types of phosphosilicate glasses with similar structures. PMID:24779999

Zeng, Huidan; Jiang, Qi; Liu, Zhao; Li, Xiang; Ren, Jing; Chen, Guorong; Liu, Fude; Peng, Shou

2014-05-15

445

Unique Construction and Social Experiences in Residential Remediation Sites - 13423  

SciTech Connect

Sevenson Environmental Services, Inc., (Sevenson) has performed several radiological remediation projects located in residential urban areas. Over the course of these projects, there has been a wide variety of experiences encountered from construction related issues to unique social situations. Some of the construction related issues included the remediation of interior basements where contaminated material was located under the footers of the structure or was used in the mortar between cinder block or field stone foundations. Other issues included site security, maintaining furnaces or other utilities, underpinning, backfilling and restoration. In addition to the radiological hazards associated with this work there were occupational safety and industrial hygiene issues that had to be addressed to ensure the safety and health of neighboring properties and residents. The unique social situations at these job sites have included arson, theft/stolen property, assault/battery, prostitution, execution of arrest warrants for residents, discovery of drugs and paraphernalia, blood borne pathogens, and unexploded ordnance. Some of these situations have become a sort of comical urban legend throughout the organization. One situation had historical significance, involving the demolition of a house to save a tree older than the Declaration of Independence. All of these projects typically involve the excavation of early 20. century items such as advertisement signs, various old bottles (milk, Listerine, perfume, whisky) and other miscellaneous common trash items. (authors)

Jung, Paul; Scarborough, Rebecca [Sevenson Environmental Services, Inc. 2749 Lockport Road, Niagara Falls, NY 14305 (United States)] [Sevenson Environmental Services, Inc. 2749 Lockport Road, Niagara Falls, NY 14305 (United States)

2013-07-01

446

Rationality, Irrationality and Escalating Behavior in Lowest Unique Bid Auctions  

PubMed Central

Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions – lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of “bid space”. The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets.

Radicchi, Filippo; Baronchelli, Andrea; Amaral, Luis A. N.

2012-01-01

447

Historical contingency and the purported uniqueness of evolutionary innovations  

PubMed Central

Many events in the history of life are thought to be singular, that is, without parallels, analogs, or homologs in time and space. These claims imply that history is profoundly contingent in that independent origins of life in the universe will spawn radically different histories. If, however, most innovations arose more than once on Earth, histories would be predictable and replicable at the scale of functional roles and directions of adaptive change. Times of origin of 23 purportedly unique evolutionary innovations are significantly more ancient than the times of first instantiation of 55 innovations that evolved more than once, implying that the early phases of life’s history were less replicable than later phases or that the appearance of singularity results from information loss through time. Indirect support for information loss comes from the distribution of sizes of clades in which the same minor, geologically recent innovation has arisen multiple times. For three repeated molluscan innovations, 28–71% of instantiations are represented by clades of five or fewer species. Such small clades would be undetectable in the early history of life. Purportedly unique innovations either arose from the union and integration of previously independent components or belong to classes of functionally similar innovations. Claims of singularity are therefore not well supported by the available evidence. Details of initial conditions, evolutionary pathways, phenotypes, and timing are contingent, but important ecological, functional, and directional aspects of the history of life are replicable and predictable.

Vermeij, Geerat J.

2006-01-01

448

Unique lithiation and delithiation processes of nanostructured metal silicides.  

PubMed

We report that TiSi(2) nanonet exhibits considerable activities in the reversible lithiation and delithiation processes, although bulk-sized titanium silicide is known to be inactive when used as an electrode material for lithium ion batteries. The detailed mechanism of this unique process was studied using electrochemical techniques including the electrochemical impedance spectroscopy (EIS) method. By systematic characterizations of the Nyquist plots and comparisons with the microstructure examinations, we identified the main reason for the activities as the layered crystal structure that is found stable only in TiSi(2) nanonets. The layer structure is characterized by the existence of a Si-only layer, which exhibits reactivity when exposed to lithium ions. Control studies where TiSi(2) nanowires and TiSi(2)/Si heteronanostructures were involved, respectively, were performed. Similar to bulk TiSi(2), TiSi(2) nanowires show limited reactivity in lithium ion insertion and deinsertion; the EIS characteristics of TiSi(2)/Si heteronanostructures, on the other hand, are distinctly different from those of TiSi(2) nanonets. The result supports our proposed TiSi(2) nanonet lithiation mechanism. This discovery highlights the uniqueness of nanoscale materials and will likely broaden the spectrum of electrode material choices for electrochemical energy storage. PMID:20942440

Zhou, Sa; Wang, Dunwei

2010-11-23

449

Quantum Gowdy T3 model: a uniqueness result  

NASA Astrophysics Data System (ADS)

Modulo a homogeneous degree of freedom and a global constraint, the linearly polarized Gowdy T3 cosmologies are equivalent to a free scalar field propagating in a fixed nonstationary background. Recently, a new field parametrization was proposed for the metric of the Gowdy spacetimes such that the associated scalar field evolves in a flat background in (1+1) dimensions with the spatial topology of S1, although subject to a time-dependent potential. Introducing a suitable Fock quantization for this scalar field, a quantum theory was constructed for the Gowdy model in which the dynamics is implemented as a unitary transformation. A question that was left open is whether one might adopt a different, nonequivalent Fock representation by selecting a distinct complex structure. The present work proves that the chosen Fock quantization is in fact unique (up to unitary equivalence) if one demands unitary implementation of the dynamics and invariance under the group of S1 translations. These translations are precisely those generated by the global constraint that remains on the Gowdy model. It is also shown that the proof of uniqueness in the choice of the complex structure can be applied to more general field dynamics than that corresponding to the Gowdy cosmologies.

Corichi, Alejandro; Cortez, Jerónimo; Mena Marugán, Guillermo A.; Velhinho, José M.

2006-11-01

450

Unique mitogenomic features in the scleractinian family pocilloporidae (scleractinia: astrocoeniina).  

PubMed

The complete DNA sequences of three mitochondrial (mt) genomes were obtained from the scleractinian corals, Stylophora pistillata, Pocillopora damicornis, and Madracis mirabilis, and were compared to the published mt genomes to elucidate phylogenetically unique features of the family Pocilloporidae. The entire mt genomes of pocilloporid corals ranged from 16,951 to 17,425 bp with the A+T contents of their sense strands ranging from 68.4% to 70.2%. The gene order of protein-coding genes was identical to those of other scleractinian corals. The novel atp8 gene, first described in confamilial Seriatopora corals, was also confirmed using reverse transcription-polymerase chain reaction (RT-PCR), Northern blot, and sequence analyses in other genera of the Pocilloporidae. The intergenic spacer between atp6 and nad4, containing distinct repeated elements, conserved sequence blocks and domains, and functional structures, possesses typical characteristics of a putative control region for the four coral genera. A duplicated trnW, detected in the region close to the cox1 gene and which shares the highly conserved primary and secondary structures of its original counterpart, was discovered in both Seriatopora and Stylophora. These molecular characteristics are unique and provide the phylogenetic information for future evaluation of the status of the family Pocilloporidae in the evolutionary history of scleractinian corals. PMID:18478295

Chen, Chienhsun; Chiou, Chih-Yung; Dai, Chang-Feng; Chen, Chaolun Allen

2008-01-01

451

Unique life sciences research facilities at NASA Ames Research Center  

NASA Technical Reports Server (NTRS)

The Life Science Division at NASA's Ames Research Center has a suite of specialized facilities that enable scientists to study the effects of gravity on living systems. This paper describes some of these facilities and their use in research. Seven centrifuges, each with its own unique abilities, allow testing of a variety of parameters on test subjects ranging from single cells through hardware to humans. The Vestibular Research Facility allows the study of both centrifugation and linear acceleration on animals and humans. The Biocomputation Center uses computers for 3D reconstruction of physiological systems, and interactive research tools for virtual reality modeling. Psycophysiological, cardiovascular, exercise physiology, and biomechanical studies are conducted in the 12 bed Human Research Facility and samples are analyzed in the certified Central Clinical Laboratory and other laboratories at Ames. Human bedrest, water immersion and lower body negative pressure equipment are also available to study physiological changes associated with weightlessness. These and other weightlessness models are used in specialized laboratories for the study of basic physiological mechanisms, metabolism and cell biology. Visual-motor performance, perception, and adaptation are studied using ground-based models as well as short term weightlessness experiments (parabolic flights). The unique combination of Life Science research facilities, laboratories, and equipment at Ames Research Center are described in detail in relation to their research contributions.

Mulenburg, G. M.; Vasques, M.; Caldwell, W. F.; Tucker, J.

1994-01-01

452

Unique Gold Nanoparticle Aggregates as a Highly Active SERS Substrate  

SciTech Connect

A unique gold nanoparticle aggregate (GNA) system has been shown to be an excellent substrate for surface-enhanced Raman scattering (SERS) applications. Rhodamine 6G (R6G), a common molecule used for testing SERS activity on silver, but generally difficult to detect on gold substrates, has been found to readily bind to the GNA and exhibit strong SERS activity due to the unique surface chemistry afforded by sulfur species on the surface. This GNA system has yielded a large SERS enhancement of 10{sup 7}-10{sup 9} in bulk solution for R6G, on par with or greater than any previously reported gold SERS substrate. SERS activity has also been successfully demonstrated for several biological molecules including adenine, L-cysteine, L-lysine, and L-histidine for the first time on a gold SERS substrate, showing the potential of this GNA as a convenient and powerful SERS substrate for biomolecular detection. In addition, SERS spectrum of R6G on single aggregates has been measured. We have shown that the special surface properties of the GNA, in conjunction with strong near IR absorption, make it useful for SERS analysis of a wide variety of molecules.

Schwartzberg, A M; Grant, C D; Wolcott, A; Talley, C E; Huser, T R; Bogomolni, R; Zhang, J Z

2004-04-06

453

Covalent Adaptable Networks (CANs): A Unique Paradigm in Crosslinked Polymers  

PubMed Central

Polymer networks possessing reversible covalent crosslinks constitute a novel material class with the capacity for adapting to an externally applied stimulus. These covalent adaptable networks (CANs) represent a trend in polymer network fabrication towards the rational design of structural materials possessing dynamic characteristics for specialty applications. Herein, we discuss the unique attributes of CANs that must be considered when designing, fabricating, and characterizing these smart materials that respond to either thermal or photochemical stimuli. While there are many reversible reactions which to consider as possible crosslink candidates in CANs, there are very few that are readily and repeatedly reversible. Furthermore, characterization of the mechanical properties of CANs requires special consideration owing to their unique attributes. Ultimately, these attributes are what lead to the advantageous properties displayed by CANs, such as recyclability, healability, tunability, shape changes, and low polymerization stress. Throughout this perspective, we identify several trends and future directions in the emerging field of CANs that demonstrate the progress to date as well as the essential elements that are needed for further advancement.

Kloxin, Christopher J.; Scott, Timothy F.; Adzima, Brian J.; Bowman, Christopher N.

2010-01-01

454

RNA molecules with structure dependent functions are uniquely folded  

PubMed Central

Cis-acting elements in post-transcriptional regulation of gene expression are often correlated with distinct local RNA secondary structure. These structures are expected to be significantly more ordered than those anticipated at random because of evolutionary constraints and intrinsic structural properties. In this study, we introduce a computing method to calculate two quantitative measures, NRd and Stscr, for estimating the uniqueness of an RNA secondary structure. NRd is a normalized score based on evaluating how different a natural RNA structure is from those predicted for its randomly shuffled variants. The lower the score NRd the more well ordered is the natural RNA structure. The statistical significance of NRd compared with that computed from structural comparisons among large numbers of randomly permuted sequences is represented by a standardized score, Stscr. We tested the method on the trans-activation response element and Rev response element of HIV-1 mRNA, internal ribosome entry sequence of hepatitis C virus, Tetrahymena thermophila rRNA intron, 100 tRNAs and 14 RNase P RNAs. Our data indicate that functional RNA structures have high Stscr, while other structures have low Stscr. We conclude that RNA functional molecules and/or cis-acting elements with structure dependent functions possess well ordered conformations and they are uniquely folded as measured by this technique.

Le, Shu-Yun; Zhang, Kaizhong; Maizel, Jacob V.

2002-01-01

455

Unique Properties of Lunar Impact Glass: Nanophase Metallic Fe Synthesis  

SciTech Connect

Lunar regolith contains important materials that can be used for in-situ resource utilization (ISRU) on the Moon, thereby providing for substantial economic savings for development of a manned base. However, virtually all activities on the Moon will be affected by the deleterious effects of the adhering, abrasive, and pervasive nature of lunar dust (<20 {micro}m portion of regolith, which constitutes {approx}20 wt% of the soil). In addition, the major impact-produced glass in the lunar soil, especially agglutinitic glass (60-80 vol% of the dust), contains unique nanometer-sized metallic Fe (np-Fe{sup 0}), which may pose severe pulmonary problems for humans. The presence of the np-Fe0 imparts considerable magnetic susceptibility to the fine portion of the lunar soil, and dust mitigation techniques can be designed using these magnetic properties. The limited availability of Apollo lunar soils for ISRU research has made it necessary to produce materials that simulate this unique np-Fe{sup 0} property, for testing different dust mitigation methods using electromagnetic fields, and for toxicity studies of human respiratory and pulmonary systems, and for microwave treatment of lunar soil to produce paved roads, etc. A method for synthesizing np-Fe{sup 0} in an amorphous silica matrix is presented here. This type of specific simulant can be used as an additive to other existing lunar soil simulants.

Liu, Yang [University of Tennessee, Knoxville (UTK); Taylor, Lawrence A. [University of Tennessee, Knoxville (UTK); Thompson, James R [ORNL; Schnare, Darren W. [University of Tennessee, Knoxville (UTK); Park, Jae-Sung [University of Tennessee, Knoxville (UTK)

2007-01-01

456

Can cosmological observations uniquely determine the nature of dark energy?  

SciTech Connect

The observational effect of all minimally coupled scalar field models of dark energy can be determined by the behavior of the following two parameters: (1) equation of state parameter w, which relates dark energy pressure to its energy density, and (2) effective speed of sound c{sub e}{sup 2}, which relates dark energy pressure fluctuation to its density fluctuation. In this paper we show that these two parameters do not uniquely determine the form of a scalar field dark energy Lagrangian even after taking into account the perturbation in the scalar field. We present this result by showing that two different forms of scalar field Lagrangian can lead to the same values for these paired parameters. It is well known that from the background evolution the Lagrangian of the scalar field dark energy cannot be uniquely determined. The two models of dark energy presented in this paper are indistinguishable from the evolution of background as well as from the evolution of perturbations from a Friedmann-Robertson-Walker metric.

Unnikrishnan, Sanil [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2008-09-15

457

Targeting unique metabolic properties of breast tumor initiating cells.  

PubMed

Normal stem cells from a variety of tissues display unique metabolic properties compared to their more differentiated progeny. However, relatively little is known about metabolic properties of cancer stem cells, also called tumor initiating cells (TICs). In this study we show that, analogous to some normal stem cells, breast TICs have distinct metabolic properties compared to nontumorigenic cancer cells (NTCs). Transcriptome profiling using RNA-Seq revealed TICs underexpress genes involved in mitochondrial biology and mitochondrial oxidative phosphorylation, and metabolic analyses revealed TICs preferentially perform glycolysis over oxidative phosphorylation compared to NTCs. Mechanistic analyses demonstrated that decreased expression and activity of pyruvate dehydrogenase (Pdh), a key regulator of oxidative phosphorylation, plays a critical role in promoting the proglycolytic phenotype of TICs. Metabolic reprogramming via forced activation