Velocity space instabilities of alpha particles in tokamak reactors

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

Sigmar, D.J.

1979-01-01

In this lecture on high frequency instability due to isotropic hollow alpha velocity distributions it was first shown that such distributions can actually arise under thermonuclear conditions in a tokamak reactor, particularly for the case of imperfect alpha particle confinement. The toroidal geometry (i.e., the poloidal variation of the alpha gyrofrequency) then leads to linear instability of the compressional Alfven wave ..omega.. = C/sub A/k/sub perpendicular/ with k/sub parallel/ congruent to O, k/sub perpendicular/ rho/sub ..cap alpha../ greater than or equal to 1, v/sub ..cap alpha../ > C/sub A/, at the low harmonics ..omega.. congruent to n ..omega../sub c..cap alpha../.more » Thus the free energy of the inverted alpha distribution is accessible and produces anomalously rapid diffusion of F/sub ..cap alpha../(v/sub perpendicular/). (MOW)« less

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

Popp, R.A.; Marsh, C.L.; Skow, L.C.

Hemoglobins of mouse embryos at 11.5 through 16.5 days of gestation were separated by electrophoresis on cellulose acetate and quantitated by a scanning densitometer to study the effects of two radiation-induced mutations on the expression of embryonic hemoglobin genes in mice. Normal mice produce three kinds of embryonic hemoglobins. In heterozygous ..cap alpha..-thalassemic embryos, expression of EI (x/sub 2/y/sub 2/) and EII (..cap alpha../sub 2/y/sub 2/) is deficient because the x- and ..cap alpha..-globin genes of one of the allelic pairs of Hba on chromosome 11 was deleted or otherwise inactivated by X irradiation. Simultaneous inactivation of the x- andmore » ..cap alpha..-globin genes indicates that these genes must be closely linked. Reduced x- and ..cap alpha..-chain synthesis results in an excess of y chains that associate as homotetramers. This unique y/sub 4/ hemoglobin also appears in ..beta..-duplication embryos where excess y chains are produced by the presence of three rather than two functional alleles of y- and ..beta..-globin genes. In double heterozygotes, which have a single functional allele of x- and ..cap alpha..-globin genes and three functional alleles of y- and ..beta..-globin genes, synthesis of ..cap alpha.. and non-..cap alpha.. chains is severely imbalanced and half of the total hemoglobin is y/sub 4/. Mouse y/sub 4/ has a high affinity for oxygen, P/sub 50/ of less than 10 mm Hg, but it lacks cooperativity so is inefficient for oxygen transport. The death of double heterozygotes in late fetal or neonatal life may be in large part to oxygen deprivation to the tissues.« less

Two subunits of the 55 K porcine zona pellucida glycoprotein family are immunologically distinct

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

Subramanian, M.G.; Yurewicz, E.C.; Sacco, A.G.

1986-03-01

The 55K glycoprotein family (ZP3) of the porcine zona pellucida is comprised of two subunits of 46 K and 45 K which can be resolved by endo-..beta..-galactosidase digestion of ZP3 followed by reversed phase HPLC on Vydac C4 resin. Gel electrophoresis revealed that the 46 K component (EBDG..cap alpha..) is approx. 95% pure and the 45 K component (EBGD..beta..) is 100% pure. In the present study, these two subunits were evaluated immunologically by RIA. Under similar reaction protocols (chloramine-T iodination procedure) comparable specific activities were obtained for EBGD..cap alpha.. (33.06 +/- 7.5 ..mu..ci/..mu..gm), EBGD..beta.. (30.45 +/- 1.6) and ZP3 (26.3more » +/- 1.3). Antibody (Ab) titration studies revealed that EBGD..cap alpha.. and ..beta.. are potent immunogens and /sup 125/I-EBGD..cap alpha.. showed minimal cross reactivity to EBGD..beta..-Ab (8% bound at 1:500 dilution), whereas, /sup 125/I-EBGD..beta.. showed a greater degree of cross reactivity to EBGD..cap alpha..-Ab (23% bound at 1:500 dilution). Maximum binding for the two labeled antigens against homologous Abs (1:500) was > 60%. Dose response studies revealed that in the /sup 125/I-EBGD..cap alpha.. vs EBGD..cap alpha.. -Ab system, the 50% intercept was 3.25 +/- 0.32 ng for EBGD..cap alpha.. and 472.43 +/- 30.26 ng for EBGD..beta.. (p < 0.01), whereas, in the /sup 125/I-EBGD..beta.. vs EBGD..beta..-Ab system the 50% intercept was 3.51 +/- 0.58 for EBGD..beta.. and 166.77 +/- 49.20 for EBGD..cap alpha.. (p < 0.01). No significant differences were observed in the slopes of the dose response curves. It is concluded that the two subunits of ZP3 possess distinct immunologic characteristics as evaluated by RIA.« less

Evidence for concerted kinetic oxidation of progesterone by purified rat hepatic cytochrome P-450g

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

Swinney, D.C.; Ryan, D.E.; Thomas, P.E.

1988-07-26

Purified cytochrome P-450g, a male-specific rat hepatic isozyme, was observed to metabolize progesterone to two primary metabolites (6..beta..-hydroxyprogesterone and 16..cap alpha..-hydroxyprogesterone), two secondary metabolites (6..beta..,16..cap alpha..-dihydroxyprogesterone and 6-ketoprogesterone), and one tertiary metabolite (6-keto-16..cap alpha..-hydroxyprogesterone). The K/sub m,app/ for the formation of these products from progesterone was determined to be approximately 0.5 ..mu..M, while the K/sub m,app/ for metabolism of 6..beta..- and 16..cap alpha..-hydroxyprogesterone was found to be 5-10 ..mu..M. The ratio of primary to secondary metabolites did not change significantly at progesterone concentrations from 6 to 150 ..mu..M, and a lag in formation of secondary metabolites was not observed inmore » 1-min incubations. Concerted oxidation of progesterone to secondary products without the intermediate products leaving the active site was suggested by these results and confirmed by isotopic dilution experiments in which little or no dilution of metabolically formed 6..beta..,16..cap alpha..-dihydroxyprogesterone and 6-keto-16..cap alpha..-hydroxyprogesterone was observed in incubations containing a mixture of radiolabeled progesterone and unlabeled 6..beta..-hydroxyprogesterone or 16..cap alpha..-hydroxyprogesterone. Incubation of 6..beta..-hydroxyprogesterone with a reconstituted system in an atmosphere of /sup 18/I/sub 2/ resulted in > 90% incorporation of /sup 18/O in the 16..cap alpha..-position of 6..beta..,16..cap alpha..-dihydroxyprogesterone but no incorporation of /sup 18/O into 6-ketoprogesterone, even though the reaction was dependent upon enzyme and O/sub 2/, and not inhibited by mannitol, catalase, or superoxide dismutase. Factors which characterize the metabolism of progesterone by cytochrome P-450g in terms of active-site constraints and the catalytic competence of the enzyme in microsomes were also explored.« less

cap alpha. -D-Mannopyranosylmethyl-P-nitrophenyltriazene effects on the degradation and biosynthesis of N-linked oligosaccharide chains on. cap alpha. /sub 1/-acid glycoprotein by liver cells

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

Docherty, P.A.; Aronson, N.N. Jr.

1986-05-01

The effects of ..cap alpha..-D-mannopyranosylmethyl-p-nitrophenyltriazene (..cap alpha..-ManMNT) on the degradation and processing of oligosaccharide chains on ..cap alpha../sub 1/-acid glycoprotein (AGP) were studied. Addition of the triazene to a perfused liver blocked the complete degradation of endocytosed N-acetyl (/sup 14/C)glucosamine-labeled asialo-AGP and caused the accumulation of Man/sub 2/GlcNAc/sub 1/ fragments in the lysosome-enriched fraction of the liver homogenate. This compound also reduced the reincorporation of lysosomally-derived (/sup 14/C)GlcNAc into newly secreted glycoproteins. Cultured hepatocytes treated with the inhibitor synthesized and secreted fully-glycosylated AGP. However, the N-linked oligosaccharide chains on AGP secreted by the ..cap alpha..-ManMNT-treated hepatocytes remained sensitive to digestionmore » with endoglycosidase H, were resistant to neuraminidase, and consisted of Man/sub 9-7/GlcNAc/sub 2/ structures as analyzed by high resolution Bio-Gel P-4 chromatography. As measured by their resistance to cleavage by endoglycosidase H, the normal processing of all six carbohydrate chains on AGP to the complex form did not completely resume until nearly 24 h after triazene treatment. Since ManMNT is likely to irreversibly inactivate ..cap alpha..-D-mannosidases, the return of AGP to secretory forms with complex chains after 24 h probably resulted from synthesis of new processing enzymes.« less

The X-ray Crystal Structures of Human {alpha}-Phosphomannomutase 1 Reveal the Structural Basis of Congenital Disorder of Glycosylation Type 1a

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

Silvaggi,N.; Zhang, C.; Lu, Z.

2006-01-01

Carbohydrate-deficient glycoprotein syndrome type 1a (CDG-1a) is a congenital disease characterized by severe defects in nervous system development. It is caused by mutations in alpha -phosphomannomutase (of which there are two isozymes, {alpha}-PMM1 and {alpha}-PPM2). Here we report the X-ray crystal structures of human {alpha}-PMM1 in the open conformation, with and without the bound substrate, {alpha}-D-mannose 1-phosphate. {alpha}-PMM1, like most Haloalkanoic Acid Dehalogenase Superfamily (HADSF) members, consists of two domains, the cap and core, which open to bind substrate and then close to provide a solvent exclusive environment for catalysis. The substrate phosphate group is observed at a positively chargedmore » site of the cap domain, rather than at the core domain phosphoryl-transfer site defined by the D19 nucleophile and Mg{sup 2+} cofactor. This suggests that substrate binds first to the cap and then is swept into the active site upon cap closure. The orientation of the acid/base residue D21 suggests that {alpha}-PMM uses a different method of protecting the aspartylphosphate from hydrolysis than the HADSF member {beta}-phosphoglucomutase. It is hypothesized that the electrostatic repulsion of positive charges at the interface of the cap and core domains stabilizes {alpha}-PMM1 in the open conformation, and that the negatively charged substrate binds to the cap, thereby facilitating its closure over the core domain. The two isozymes {alpha}-PMM1 and {alpha}-PMM2 are shown to have a conserved active-site structure and to display similar kinetic properties. Analysis of the known mutation sites in the context of the structures reveals the genotype-phenotype relationship underlying CDG-1a.« less

Genomic organization and sequence of the Gus-s/sup a/ allele of the murine. beta. -glucuronidase gene

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

Funkenstein, B.; Leary, S.L.; Stein, J.C.

1988-03-01

The Gus-s/sup ..cap alpha../ allele of the mouse ..beta..-glucuronidase gene exhibits a high degree of inducibility by androgens due to its linkage with the Gus-r/sup ..cap alpha../ regulatory locus. The authors isolated Gus-s/sup ..cap alpha../ on a 28-kilobase pair fragment of mouse chromosome 5 and found that it contains 12 exons and 11 intervening sequences spanning 14 kilobase pairs of this genomic segment. The mRNA cap site was identified by ribonuclease protection and primer extension analyses which revealed an unusually short 5' noncoding sequence of 12 nucleotides. Proximal regulatory sequences in the 5'-flanking DNA and the complete sequence of themore » Gus-s/sup ..cap alpha../ mRNA transcript were also determined. Comparison of the amino acid sequence determined from the Gus-s/sup ..cap alpha../ nucleotide sequence with that of human ..beta..-glucuronidase indicated that the two human mRNA species differ due to alternate splicing of an exon homologous to exon 6 of the mouse gene.« less

Creatine kinase and alpha-actin mRNA levels decrease in diabetic rat hearts

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

Popovich, B.; Barrieux, A.; Dillmann, W.H.

1987-05-01

Diabetic cardiomyopathy is associated with cardiac atrophy and isoenzyme redistribution. To determine if tissue specific changes occur in mRNAs coding for ..cap alpha..-actin and creatine kinase (CK), they performed RNA blot analysis. Total ventricular RNA from control (C) and 4 wk old diabetic (D) rats were hybridized with /sup 32/P cDNA probes for ..cap alpha..-actin and CK. A tissue independent cDNA probe, CHOA was also used. Signal intensity was quantified by photodensitometry. D CK mRNA was 47 +/- 16% lower in D vs C. Insulin increases CK mRNA by 20% at 1.5 hs, and completely reverses the deficit after 4more » wks. D ..cap alpha..-actin mRNA is 66 +/- 18% lower in D vs C. Insulin normalized ..cap alpha..-actin mRNA by 5 hs. CHOA mRNA is unchanged in D vs C, but D + insulin CHOA mRNA is 30 +/- 2% lower than C. In rats with diabetic cardiomyopathy, muscle specific CK and ..cap alpha..-actin mRNAs are decreased. Insulin treatment reverses these changes.« less

Gamma-resonance investigation of the kinetics of the reduction of (. cap alpha. -benzil dioximato-1)(. cap alpha. -benzil dioximato-2)di(pyridine)iron(III)

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

Turte, K.I.; Bulgak, I.I.; Stukan, R.A.

1986-07-01

(..cap alpha..-Benzil dioximato-1)(..cap alpha..-benzil dioximato-2)di(pyridine)iron(III) in the form of the diacetone solvate (II) is spontaneously converted at room temperature into (..cap alpha..-benzil dioximato-1)(..cap alpha..-benzil dioximato-2)di(pyridine)iron(II) (III). The quantitative composition of a sample containing complexes II and III has been determined as a function of the temperature and the time by gamma-resonance spectroscopy, which made it possible to investigate the kinetics of this reaction. The changes obtained in the percentage of complex II in the sample as a function of time at a given temperature was treated with the use of the Kolmogorov-Erofeev equation for a topochemical reaction of the typemore » A/sub s/ ..-->.. B/sub s/ + C/sub g/. The rate constants of the reaction at various temperatures and the activation energy *E have been determined. In the temperature range from 293 to 304/sup 0/K *E = 25.6 kcal/mole. The possibilities of gamma-resonance spectroscopy in the investigation of topochemical reactions associated with changes in the oxidation state of iron ions have been demonstrated.« less

Reconstitution of high affinity. cap alpha. /sub 2/ adrenergic agonist binding by fusion with a pertussis toxin substrate

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

Kim, M.H.; Neubig, R.R.

1986-03-05

High affinity ..cap alpha../sub 2/ adrenergic agonist binding is thought to occur via a coupling of the ..cap alpha../sub 2/ receptor with N/sub i/, the inhibitory guanyl nucleotide binding protein. Human platelet membranes pretreated at pH 11.5 exhibit a selective inactivation of agonist binding and N/sub i/. To further study the mechanism of agonist binding, alkali treated membranes (ATM) were mixed with membranes pretreated with 10 ..mu..M phenoxybenzamine to block ..cap alpha../sub 2/ receptors (POB-M). The combined membrane pellet was incubated in 50% polyethylene glycol (PEG) to promote membrane-membrane fusion and assayed for binding to the ..cap alpha../sub 2/ agonistmore » (/sup 3/H)UK 14,304 (UK) and the antagonist (/sup 3/H) yohimbine. PEG treatment resulted in a 2-4 fold enhancement of UK binding whereas yohimbine binding was unchanged. No enhancement of UK binding was observed in the absence of PEG treatment. The reconstitution was dependent on the addition of POB-M. They found that a 1:1 ratio of POB-M:ATM was optimal. Reconstituted binding was inhibited by GppNHp. Fusion of rat C6 glioma cell membranes, which do not contain ..cap alpha../sub 2/ receptors, also enhanced agonist binding to ATM. Fusion of C6 membranes from cells treated with pertussis toxin did not enhance (/sup 3/H) UK binding. These data show that a pertussis toxin sensitive membrane component, possibly N/sub i/, can reconstitute high affinity ..cap alpha../sub 2/ agonist binding.« less

Ionization of isocitrate bound to pig hear NADP/sup +/-dependent isocitrate dehydrogenase: /sup 13/C NMR study of substrate binding

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

Ehrlich, R.S.; Colman, R.F.

1987-06-16

Isocitrate and ..cap alpha..-ketoglutarate have been synthesized with carbon-13 enrichment at specific positions. The /sup 13/C NMR spectra of these derivatives were measured as a function of pH. The magnitudes of the changes in chemical shifts with pH for free isocitrate and the magnesium-isocitrate complex suggest that the primary site of ionization at the ..beta..-carboxyl. In the presence of the enzyme NADP/sup +/-dependent isocitrate dehydrogenase and the activating metal magnesium, the carbon-13 resonances of all three carboxyls remain constant from pH 5.5 to pH 7.5. Thus, the carboxyls remain in the ionized form in the enzyme-isocitrate complex. The ..cap alpha..-hydroxylmore » carbon resonance could not be located in the enzyme-isocitrate complex, suggesting immobilization of this group. Magnesium produces a 2 ppm downfield shift of the ..beta..-carboxyl but does not change the resonances of the ..cap alpha..- and ..gamma..-carboxyls. This result is consistent with metal activation of both the dehydrogenation and decarboxylation reactions. The /sup 13/C NMR spectrum of ..cap alpha..-ketoglutarate remains unchanged in the presence of isocitrate dehydrogenase, implying the absence of alterations in geometry in the enzyme-bound form. Formation of the quaternary complex with Mg/sup 2 +/ and NADPH leads to loss of the ..cap alpha..-ketoglutarate resonances and the appearance of new resonances characteristic of ..cap alpha..-hydroxyglutarate. In addition, a broad peak ascribed to the enol form of ..cap alpha..-ketoglutarate is observed. The substantial change in the shift of the ..beta..-carboxyl of isocitrate and the lack of significant shifts in the other carboxyls of isocitrate or ..cap alpha..-ketoglutarate suggest that interaction of the ..beta..-carboxyl with the enzyme contributes to the tighter binding of isocitrate and may be significant for the oxidative decarboxylation function of isocitrate dehydrogenase.« less

Lyman-alpha observations of comet Kohoutek 1973 XII with Copernicus

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

Drake, J.F.; Jenkins, E.B.; Bertaux, J.L.

1976-10-01

Comet Kohoutek 1973 XII was observed with the Princeton telescope-spectrometer on the Copernicus satellite on six occasions over a 1-month period starting on 1974 January 29. Positive detection of the cometary L..cap alpha.. emission profile was obtained on January 29 and February 2. Earlier observations of the geocoronal L..cap alpha.. emission profile allowed an instrumental intensity calibration and confirmation of the computed instrumental profile for an extended source at the L..cap alpha.. wavelength.After allowing for broadening by the instrument, we derived from the width of the L..cap alpha.. emission on January 29 a hydrogen-outflow velocity of 10.6 +- 1.8 kmmore » s/sup -1/. The intensity calibration combined with an appropriate cometary model led to cometary water-production rates with average values of 1.3 +- 0.4 x 10/sup 28/ molecules sr/sup -1/ s/sup -1/ for January 29 and 6.0 +- 2.5 x 10/sup 27/ molecules sr/sup -1/ s/sup -1/ for February 2. Only upper limits were obtained for L..cap alpha.. on and after February 14. Searches for OH and D led to negative results. (AIP)« less

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

Chan, R.K.; Otte, C.A.

Saccharomyces cerevisiae MATa cells carrying mutations in either sst1 or sst2 are supersensitive to the G1 arrest induced by ..cap alpha.. factor pheromone. When sst1 mutants were mixed with normal SST/sup +/ cells, the entire population recovered together from ..cap alpha.. factor arrest, suggesting that SST/sup +/ cells helped sst1 mutants to recover. Complementation tests and linkage analysis showed that sst1 and bar1, a mutation which eliminates the ability of MATa cells to act as a ''barrier'' to the diffusion of ..cap alpha.. factor, were lesions in the same genes. These findings suggest that sst1 mutants are defective in recoverymore » from ..cap alpha.. factor arrest because they are unable to degrade the pheromone. In contrast, recovery of sst2 mutants was not potentiated by the presence of SST/sup +/ cells in mixing experiments. When either normal MATa cells or mutant cells carrying defects in sst1 or sst2 were exposed to ..cap alpha.. factor for 1 h and then washed free of the pheromone, the sst2 cells subsequently remained arrested in the absence of ..cap alpha.. factor for a much longer time than SST/sup +/ or sst1 cells. These observations suggest that the defect in sst2 mutants is intrinsic to the cell and is involved in the mechanism of ..cap alpha.. factor action at some step after the initial interaction of the pheromone with the cell. The presence of an sst2 mutation appears to cause a growth debility, since repeated serial subculture of haploid sst2-1 strains led to the accumulation of faster-growing revertants that were pheromone resistant and were mating defective (''sterile'').« less

Isolation of human hexosaminidase. cap alpha. cDNA and expression of. cap alpha. chains in E. coli

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

Wiktorowicz, J.E.; Whitman, J.M.

1986-05-01

Pooled antisera against homogeneous, glutaraldehyde cross-linked hexosaminidase (hex) A was adsorbed with E. coli lysate insolubilized on Sepharose 4B. Aliquots of a human liver lambdagtll cDNA library (50,000-100,000 pfu) were plated on E. coli Y1090. Expression of cloned cDNA, after sufficient plaque growth at 42/sup 0/, was accomplished by induction with isopropylthiogalactoside soaked nitrocellulose filters. Identification of hex cDNA clones was performed by incubation of the filters with purified antisera. Protein A labelled with I-125 was used to develop the reactive plaques. Positive plaques, identified by autoradiography, were picked, replated at a lower density, and rescreened. This was repeated severalmore » more times until all plaques yielded positive signals. Identification of the clones as containing ..cap alpha.. or ..beta.. cDNA was accomplished by replating the purified phage and rescreening the plaques with anti-hex B antiserum preadsorbed with E. coli lysate. According to this protocol several hex ..cap alpha.. clones have been identified. While these clones generate ..beta..-galactosidase: hex ..cap alpha.. fusion proteins, these findings suggest that in the future it may be possible to obtain large quantities of unmodified hex ..cap alpha.. and ..beta.. polypeptides from E. coli for the study of the structural and enzymatic properties of these polypeptides and for diagnostic purposes in the GM2 gangliosidoses.« less

Pulse radiolysis and 77 K matrix. gamma. irradiation of dimethyl truxinates and trans-methyl cinnamate in 2-methyltetrahydrofuran

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

Takamuku, S.; Kigawa, H.; Suematsu, H.

1982-05-13

One-electron reduction of dimethyl ..mu..-truxinate (..mu..-DMT), dimethyl ..beta..-truxinate (..beta..-DMT), and dimethyl ..cap alpha..-truxillate (..cap alpha..-DMT) has been investigated by pulse radiolysis and 77 K matrix ..gamma.. irradiation of the 2-methyltetrahydrofuran solutions. Cycloreversion of the radical anions formed by an electron attachment to these cyclobutanes was observed in all cases, even at 77 K. The orientation of the cycloreversion was dependent on the stereochemistry of the cyclobutanes, and the selectivity was reasonably explained by a so-called cis effect; the best possible release of steric hindrance decides the primary step of the reaction. In 77 K matrix ..gamma.. irradiation of ..cap alpha..-DMT,more » an intense IR absorption was found after the photobleaching of trapped electrons with light > 690 nm. In other DMTs, the IR absorption band was not observed while the cycloreversion of DMT by mobile electrons occurred. Thus, the IR band in the case of ..cap alpha..-DMT was assigned to an associated dimer anion due to the interaction between the radical anion and the neutral molecule pair of trans-methyl cinnamate orginally formed by the cycloreversion of ..cap alpha..-DMT. The dimer anion was presumed to be oriented in a head-to-tail structure in a solvent cage on the basis of the original configuration of ..cap alpha..-DMT.« less

Pheromone induction of agglutination in Saccharomyces cerevisiae a cells

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

Terrance, K.; Lipke, P.N.

1987-10-01

a-Agglutinin, the cell surface sexual agglutinin of yeast a cells, was assayed by its ability to bind its complementary agglutinin, ..cap alpha..-agglutinin. The specific binding of /sup 125/I-..cap alpha..-agglutinin to a cells treated with the sex pheromone ..cap alpha..-factor was 2 to 2.5 times that of binding to a cells not treated with ..cap alpha..-factor. Competition with unlabeled ..cap alpha..-agglutinin revealed that the increased binding was due to increased cell surface expression of a-agglutinin, with no apparent change in the binding constant. The increase in site number was similar to the increase in cellular agglutinability. Increased expression of a-agglutinin followedmore » the same kinetics as the increase in cellular agglutinability, with a 10-min lag followed by a 15- to 20-min response time. Induction kinetics were similar in cells in phases G1 and G2 of the cell cycle. Maximal expression levels were similar in cells treated with excess pheromone and in cells exposed to pheromone after destruction of constitutively expressed a-agglutinin.« less

{sup 110,116}Cd({alpha},{alpha}){sup 110,116}Cd elastic scattering and systematic investigation of elastic {alpha} scattering cross sections along the Z=48 isotopic and N=62 isotonic chains

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

Kiss, G. G.; Fueloep, Zs.; Gyuerky, Gy.

2011-06-15

The elastic scattering cross sections for the reactions {sup 110,116}Cd({alpha},{alpha}){sup 110,116}Cd at energies above and below the Coulomb barrier are presented to provide a sensitive test for the {alpha}-nucleus optical potential parameter sets. Additional constraints for the optical potential are taken from the analysis of elastic scattering excitation functions at backward angles which are available in literature. Moreover, the variation of the elastic {alpha} scattering cross sections along the Z=48 isotopic and N=62 isotonic chain is investigated by the study of the ratios of the {sup 106,110,116}Cd({alpha},{alpha}){sup 106,110,116}Cd scattering cross sections at E{sub cm{approx_equal}}15.6and18.8 MeV and the ratio of themore » {sup 110}Cd({alpha},{alpha}){sup 110}Cd and {sup 112}Sn({alpha},{alpha}){sup 112}Sn reaction cross sections at E{sub cm{approx_equal}}18.8 MeV, respectively. These ratios are sensitive probes for the {alpha}-nucleus optical potential parametrizations. The potentials under study are a basic prerequisite for the prediction of {alpha}-induced reaction cross sections (e.g., for the calculation of stellar reaction rates in the astrophysical p or {gamma} process).« less

Metabolism of 4-chlorobenzotrichloride in rats

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

Quistad, G.B.; Mulholland, K.M.; Skiles, G.

Special analytical methodology was developed for purification of 4-chloro(/sup 14/C)benzotrichloride, which is both volatile and hydrolytically unstable at milligram mass levels. When rats were given a single oral dose of 4-chloro(/sup 14/C)benzotrichloride at 1.5 mg/kg, within 4-6 days 87 and 9% of the applied /sup 14/C were excreted in urine and feces, respectively. The major urinary metabolite was identified as 4-chlorohippuric acid, representing 78% of the applied dose. While about two-thirds of the fecal /sup 14/C residues were unextractable with organic solvents, free 4-chlorobenzoic acid and ..cap alpha..,..cap alpha..,4,4'-tetrachlorostilbene contributed 10 and 8% of the fecal /sup 14/C. The metabolicmore » production of ..cap alpha..,..cap alpha..,4,4'-tetrachlorostilbene appears to occur by a novel metabolic pathway.« less

cap alpha. -Methylglucoside satisfies only Na/sup +/-dependent transport system of intestinal epithelium

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

Kimmich, G.A.; Randles, J.

1981-01-01

The unidirectional influx of ..cap alpha..-methylglucoside (..cap alpha..-MG) by isolated chicken intestinal epithelial cells is 98% inhibited by phlorizin. The remaining 2% of the total influx occurs in the absence of Na/sup +/, is not sensitive to phloretin, and is equal to the diffusional entry rate for 2-deoxyglucose. The glucoside is much more strongly accumulated (75-fold) than 3-O-methylglucose (3-OMG) (10-fold). Inhibitors of the serosal sugar carrier (phloretin, cytochalasin B, theophylline, and flavanoids) do not enhance ..cap alpha..-MG accumulation. It is concluded that the glycoside is not a substrate for the intestinal serosal transport system. Steady-state gradients of the sugar canmore » be represented accurately by a concentrative, phlorizin-sensitive system that is opposed by a diffusional efflux process.« less

Characterization of rat leydig cell gonadotropin receptor structure by affinity cross-linking

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

Zhang, Q.Y.; Hwang, J.; Menon, K.M.J.

1986-05-01

The gonadotropin receptor from rat leydig cell has been characterized with respect to binding kinetics and physiological regulation. The present study was intended to examine the structure of the receptor. Leydig cell suspension was prepared by either collagenase digestion or by mechanical disruption of the testis. The cells were incubated with /sup 125/I-hCG and the unreacted hCG was removed by centrifugation. The /sup 125/I-hCG was then covalently linked to the cell surface receptor using cleavable (dithiobis (succinimidyl propionate)) and non-cleavable (disuccinimidyl suberate) cross-linking reagents. The extracted cross-linked membrane proteins were resolved on SDS-polyacrylamide gels under reducing and non-reducing conditions andmore » subjected to autoradiographic analysis. Under non-reducing conditions, two labeled species with M/sub r/ = 87,000 and 120,000 were detected. However, only one labeled band was detected under reducing conditions with M/sub r/ = 64,000. The binding of /sup 125/I-hCG to the receptor was inhibited by hCG and LH, but not by a number of peptides and proteins. The data suggest that hCG receptor in leydig cell is an oligomeric complex consisting of four subunits, ..cap alpha cap alpha beta gamma... The ..beta.. and ..gamma.. subunits are each linked to an ..cap alpha.. subunit through disulfide linkage and the hormone binds to each ..cap alpha.. subunit. The two dimers formed (..cap alpha beta cap alpha gamma..) are associated by noncovalent interactions.« less

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

Yamashita, T.; Fujino, T.; Masaki, N.

The structural parameters of ..cap alpha..- and ..beta..-CdUO/sub 4/ crystals are determined by x-ray powder diffraction technique. ..cap alpha..-CdUO/sub 4/ is rhombohedral and cell parameters are a = 6.233(3) A and ..cap alpha.. = 36.12(5)/sup 0/. ..beta..-CdUO/sub 4/ crystallizes in a C-centered orthorhombic cell with a = 7.023(4), b = 6.849(3), c = 3.514(2) A. The space groups are R3m for ..cap alpha..-CdUO/sub 4/ and Cmmm for ..beta..-CdUO/sub 4/. ..cap alpha..-CdUO/sub 4/: 1U in (000), 1Cd in (1/2 1/2 1/2), 2O(1) in +-(uuu), 2O(2) in +-(vvv); u = 0.113, v= 0.350, Z = 1. ..beta..-CdUO/sub 4/: 2U in (000; 1/2more » 1/2 0), 2Cd in (1/2 0 1/2; 0 1/2 1/2), 40(1) in (0, +-y, 0; 1/2, 1/2 +-y, 0), 4O(2) in (+-x, 0, 1/2; 1/2 +-x, 1/2, 1/2); x = 0.159, y = 0.278, Z = 2. ..beta..-CdUO/sub 4/ contains collinear uranyl UO/sub 2//sup 2 +/ groups with a U-O(1) distance of 1.91 A, located either along or parallel to the c axis whereas the U-O(1) bond length in ..cap alpha..-CdUO/sub 4/ is 1.98 A which is longer than the usual uranyl bond length.« less

Computational comparison of tibial diaphyseal fractures fixed with various degrees of prebending of titanium elastic nails and with and without end caps.

PubMed

Chen, Yen-Nien; Lee, Pei-Yuan; Chang, Chih-Han; Chang, Chih-Wei; Ho, Yi-Hung; Li, Chun-Ting; Peng, Yao-Te

2016-10-01

Elastic stable intramedullary nailing (ESIN) is a treatment strategy for the management of diaphyseal long-bone fractures in adolescents and children, but few studies have investigated the mechanical stability of tibial diaphyseal fractures treated with various degrees of prebending of the elastic nails. Therefore, the aim of this study was to compare the mechanical stability, including the gap deformation and nail dropping, of a tibia fracture with various fracture sites and fixed with various degrees of prebending of the elastic nails by the finite element method. Furthermore, the contribution of end caps to stability was taken into consideration in the simulation. A tibia model was developed with a transverse fracture at the proximal, middle and distal parts of the diaphysis, and fixed with three degrees of prebending of elastic nails, including those equal to, two times and three times the diameter of the intramedullary canal. The outer diameter of the nail used in the computation was 3.5mm, and the fractured tibia was fixed with two elastic double C-type nails. Furthermore, the proximal end of each nail was set to free or being tied to the surrounding bone by a constraint equation to simulate with or without using end caps. The results indicated that using end caps can prevent the fracture gap from collapsing by stopping the ends of the nails from dropping back in all prebending conditions and fracture patterns, and increasing the prebending of the nails to a degree three times the diameter of the canal reduced the gap shortening and the dropping distance of the nail end in those without using end caps under axial compression and bending. Insufficient prebending of the nails and not using end caps caused the gap to collapse and the nail to drop back at the entry point under loading. Using end caps or increasing the prebending of the nails to three times the diameter of the canal is suggested to stop the nail from dropping back and thus produce a more stable structure, with less gap deformation, in the management of a simulated tibial diapyhseal fracture by using titanium elastic nails with a double C-shape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variability of Lyman-alpha emission from Jupiter

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

Cochran, W.D.; Barker, E.S.

1979-12-01

The Jovian L..cap alpha.. emission line was reobserved in 1978 March using the high-resolution spectrometer of the Copernicus satellite. An intensity of 8.3 +- 2.9 kilorayleighs was measured. This value represents a significant increase in intensity over previous (1976) Copernicus observations, but is lower than the recent (1979) values obtained by Voyager 1 and IUE. The increase in intensity has been accompanied by a significant increase in line width givin strong support to the theory that the emission results from resonant scattering of the solar L..cap alpha.. line by H atoms in the upper Jovian atmosphere. The strength of Jovianmore » L..cap alpha.. emission correlates well with the level of solar activity. The solar extreme ultraviolet radiation varies with the solar cycle. This radiation causes the dissociation of H/sub 2/ and CH/sub 4/ into H atoms in the Jovian atmosphere. Therefore, in times of high solar activity, the H column density will increase, causing the observed stronger Jovian L..cap alpha.. emission.« less

A remarkable member of the polyoxometalates: the eight-nickel-capped alpha-keggin polyoxoazonickelate.

PubMed

Dong, Lanjun; Huang, Rudan; Wei, Yongge; Chu, Wei

2009-08-17

The eight-nickel-capped polyoxoazonickelate, [Ni(20)(OH)(24)(MMT)(12)(SO(4))](NO(3))(2).6H(2)O (1; MMT = 2-mercapto-5-methyl-1,3,4-thiadiazole), has been synthesized, which has an alpha-Keggin structure with eight nickel caps. In this structure, the polyatom is the late transition metal Ni(II); the central heteroatom is S, and the organic terminal ligand becomes the primary part of the Keggin structure. This is a Keplerate-type cluster, which shows a central Ni(II)(12) cuboctahedron formed by the 12 Ni(II) centers of the classical alpha-Keggin core and a Ni(II)(8) hexahedron formed by the eight nickel caps.

Glucocorticoids inhibit coordinated translation of. cap alpha. - and. beta. -globin mRNAs in Friend erythroleukemia cells

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

Papaconstantinou, J.; Stewart, J.A.; Rabek, J.P.

The dimethylsulfoxide (Me/sub 2/SO)-mediated induction of hemoglobin synthesis in Friend erythroleukemia cells is inhibited by the glucocorticoids hydrocortisone, dexamethasone, and fluocinolone acetonide; hydrocortisone, at concentrations of 10/sup -5/ to 10/sup -8/ M inhibits by 90-30% and fluocinolone acetonide at concentrations of 10/sup -8/ to 10/sup -11/ M shows a greater than 90% inhibition. At these concentrations the hormones have no effect on cell growth or viability. In this study it has been shown that there is a group of proteins, including the ..cap alpha..- and ..beta..-globins, whose regulation is associated with the induction of Friend erythroleukemia cell differentiation, and thatmore » the expression of these, in addition to ..cap alpha..- and ..beta..-globin, is affected by glucocorticoids. It is concluded that, although the translation of ..cap alpha..- and ..beta..-globin mRNA is a major site of inhibition by glucocorticoids, there is a detectable amount of ..cap alpha..- and ..beta..-globin mRNA translation which results in unequal amounts of globin synthesis and an overall more potent inhibition of hemoglobin formation.« less

X-ray fluorescence cross sections for K and L x rays of the elements

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

Krause, M.O.; Nestor, C.W. Jr.; Sparks, C.J. Jr.

1978-06-01

X-ray fluorescence cross sections are calculated for the major x rays of the K series 5 less than or equal to Z less than or equal to 101, and the three L series 12 less than or equal to Z less than or equal to 101 in the energy range 1 to 200 keV. This calculation uses Scofield's theoretical partical photoionization cross sections, Krause's evaluation of fluorescence and Coster-Kronig yields, and Scofield's theoretical radiative rates. Values are presented in table and graph format, and an estimate of their accuracy is made. The following x rays are considered: K..cap alpha../sub 1/,more » K..cap alpha../sub 1/,/sub 2/, K..beta../sub 1/, K..beta../sub 1/,/sub 3/, L..cap alpha../sub 1/, L..cap alpha../sub 1/,/sub 2/, L..beta../sub 1/, L..beta../sub 2/,/sub 15/, L..beta../sub 3/, Ll, L..gamma../sub 1/, L..gamma../sub 4/, and L/sub 1/ ..-->.. L/sub 2/,/sub 3/. For use in x-ray fluorescence analysis, K..cap alpha.. and L..cap alpha.. fluorescence cross sections are presented at specific energies: TiK identical with 4.55 keV, CrK identical with 5.46 keV, CoK identical with 7.00 keV, CuK identical with 8.13 keV, MoK..cap alpha.. identical with 17.44 keV, AgK identical with 22.5 keV, DyK identical with 47.0 keV, and /sup 241/Am identical with 59.54 keV. Supplementary material includes fluorescence and Coster--Kronig yields, fractional radiative rates, fractional fluorescence yields, total L-shell fluorescence cross sections, fluorescence and Coster-Kronig yields in condensed matter, effective fluorescence yields, average L-shell fluorescence yield, L-subshell photoionization cross section ratios, and conversion factors from barns per atom to square centimeters per gram.« less

Cross-linking of hCG to luteal receptors

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

Ji, T.H.; Ji, I.

1985-01-01

Photoaffinity labeling of the lutropin/choriogonadotropin (LH/hCG) receptor system on porcine granulosa cells has demonstrated that both the ..cap alpha.. and ..beta.. subunits of hCG directly photoaffinity label the hormone receptor. Three new bands appear on SDS-PAGE as a consequence of photoaffinity labeling by each subunit: the molecular weights of the three bands (106K, 88K, and 83K) produced by the subunit are larger by approximately 10K than those of the three bands (96K, 76K, and 73K) labeled by the ..cap alpha.. subunit. Although it could be a coincidence that the molecular weight of the ..beta.. subunit is approximately 10K larger thanmore » that of the ..cap alpha.. subunit, the similarity in these differences suggests the possibility that both the ..cap alpha.. and ..beta.. subunits have labeled the same polypeptides.« less

Differentiation to adipocytes in accompanied by an increase in the amounts of Gi- and Go-proteins in 3T3-L1 cells

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

Watkins, D.C.; Northup, J.K.; Malbon, C.C.

Treatment of cultures of 3T3-L1 cells with methylisobutyl-xanthine and dexamethasone has been shown to result in accumulation of lipid and conversion to the morphology of adipocytes in more than 90% of the cells. The status of the stimulatory (Gs), inhibitory (Gi) and Go-proteins during the course of 3T3-L1 differentiation was examined. The amount of alpha subunit of Gs (..cap alpha..Gs), assayed by radiolabeling in the presence of cholera toxin and (/sup 32/P)NAD/sup +/, increased upon differentiation as previously described by others. The amounts of ..cap alpha..Gi and ..cap alpha..Go assayed by radiolabeling in the presence of pertussis toxin and (/supmore » 32/P)NAD/sup +/ increased 3-fold upon differentiation. Immunoblots of cell membranes subjected to gel electrophoresis in sodium dodecyl sulfate were probed with two rabbit antisera raised against bovine brain ..cap alpha..Go and with one raised against the..beta..-subunit of the bovine rod-outer-segment G-protein, referred to as transducin. The immunoblotting data confirm the increase upon differentiation of ..cap alpha..Go and also demonstrate an increase in the amount of the ..beta..-subunit. Thus differentiation of 3T3-L1 cells is accompanied by dramatic changes in the complexion of G-proteins in the membranes.« less

cap alpha. /sub 2/-Adrenergic receptor-mediated sensitization of forskolin-stimulated cyclic AMP production

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

Jones, S.B.; Toews, M.L.; Turner, J.T.

1987-03-01

Preincubation of HT29 human colonic adenocarcinoma cells with ..cap alpha../sub 2/-adrenergic agonists resulted in a 10- to 20-fold increase in forskolin-stimulated cyclic AMP production as compared to cells preincubated without agonist. Similar results were obtained using either a (/sup 3/H)adenine prelabeling assay or a cyclic AMP radioimmunoassay to measure cyclic AMP levels. This phenomenon, which is termed sensitization, is ..cap alpha../sub 2/-adrenergic receptor-mediated and rapid in onset and reversal. Yohimbine, an ..cap alpha../sub 2/-adrenergic receptor-selective antagonist, blocked norepinephrine-induced sensitization, whereas prazosin (..cap alpha../sub 1/-adrenergic) and sotalol (..beta..-adrenergic) did not. The time for half-maximal sensitization was 5 min and the half-timemore » for reversal was 10 min. Only a 2-fold sensitization of cyclic AMP production stimulated by vasoactive intestinal peptide was observed, indicating that sensitization is relatively selective for forskolin. Sensitization reflects an increased production of cyclic AMP and not a decreased degradation of cyclic AMP, since incubation with a phosphodiesterase inhibitor and forskolin did not mimic sensitization. Increasing the levels of cyclic AMP during the preincubation had no effect on sensitization, indicating that sensitization is not caused by decreased cyclic AMP levels during the preincubation. This rapid and dramatic sensitization of forskolin-stimulated cyclic AMP production is a previously unreported effect that can be added to the growing list of ..cap alpha../sub 2/-adrenergic responses that are not mediated by a decrease in cyclic AMP.« less

Role of a guanine nucleotide-binding protein in. cap alpha. /sub 1/-adrenergic receptor-mediated Ca/sup 2 +/ mobilization in DDT/sub 1/ MF-2 cells

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

Cornett, L.E.; Norris, J.S.

1987-11-01

In this study the mechanisms involved in ..cap alpha../sub 1/-adrenergic receptor-mediated Ca/sup 2 +/ mobilization at the level of the plasma membrane were investigated. Stimulation of /sup 45/Ca/sup 2 +/ efflux from saponin-permeabilized DDT/sub 1/ MF-2 cells was observed with the addition of either the ..cap alpha../sub 1/-adrenergic agonist phenylephrine and guanosine-5'-triphosphate or the nonhydrolyzable guanine nucleotide guanylyl-imidodiphosphate. In the presence of (/sup 32/P) NAD, pertussis toxin was found to catalyze ADP-ribosylation of a M/sub r/ = 40,500 (n = 8) peptide in membranes prepared from DDT/sub 1/, MF-2 cells, possibly the ..cap alpha..-subunit of N/sub i/. However, stimulation ofmore » unidirectional /sup 45/Ca/sup 2 +/ efflux by phenylephrine was not affected by previous treatment of cells with 100 ng/ml pertussis toxin. These data suggest that the putative guanine nucleotide-binding protein which couples the ..cap alpha../sub 1/-adrenergic receptor to Ca/sup 2 +/ mobilization in DDT/sub 1/ MF-2 cells is not a pertussis toxin substrate and may possibly be an additional member of guanine nucleotide binding protein family.« less

E2C mechanism of elimination reactions. IX. Secondary deuterium isotope effects on rates of bimolecular reactions in alicyclic systems

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

Cook, D.

1976-06-11

Secondary ..cap alpha..-deuterium isotope effects on the rates of NBu/sub 4/OAc and NBu/sub 4/Cl promoted bimolecular reactions (E2 and SN2) of cyclohexyl tosylate and cyclohexyl bromide have been studied. The E2 reactions, previously categorized as E2C-like, show ..cap alpha..-deuterium isotope effects in the range 1.14--1.22, while the related SN2 reactions give values in the range 1.05--1.08. The discrepancy in the magnitude of the ..cap alpha..-deuterium isotope effect for the E2 and SN2 processes is consistent with the view that E2C-like reactions use ''looser'' transition states than those used in the concurrent SN2 reactions. While the reported ..cap alpha..-d isotope effectsmore » do not provide positive evidence to support the idea that the base interacts with C/sub ..cap alpha../ in the E2 transition states of the reactions studied, neither do they substantiate claims for dismissal of the concept. A comparison of the secondary ..gamma..-deuterium and ..beta..'-deuterium isotope effects arising in the reaction of cyclohexyl tosylate with NBu/sub 4/OAc in acetone indicates the two isotope effects to be of equivalent magnitude (k/sub ..beta..'-d/k/sub ..gamma..-d/ = 0.98). This observation can only be rationalized for this reaction in terms of a transition state structure in which there is extensive double bond development. It provides compelling evidence against the involvement of any transition state structure which accommodates extensive positive charge development at C/sub ..cap alpha../.« less

Alpha particle effects in burning tokamak plasmas: overview and specific examples

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

Sigmar, D.J.

1986-07-01

Using the total power balance of an ignited tokamak plasma as a guideline, a range of alpha driven effects is surveyed regarding their impact on achieving and maintaining fusion burn. Specific examples of MHD and kinetic modes and multi species transport dynamics are discussed, including the possible interaction of these categories of effects. This power balance approach rather than a straightforward enumeration of possible effects serves to reveal their non-linear dependence and the ensuing fragility of our understanding of the approach to and maintenance of ignition. Specific examples are given of the interaction between ..cap alpha..-power driven sawtoothing and idealmore » MHD stability, and direct ..cap alpha..-effects on MHD modes including kinetic corrections. Anomalous ion heat transport and central impurity peaking mechanisms and anomalous and collisional ..cap alpha..-transport including the ambipolar electric field are discussed.« less

Highly excited states in /sup 6/Li by the reaction /sup 9/Be(p,. cap alpha. )/sup 6/Li. [Width of 8. 2-MeV level

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

Delbar, T.; Gregoire, G.; Lega, J.

1976-10-01

The spectra from the reaction /sup 9/Be(p, ..cap alpha..)/sup 6/Li induced by 75 and 30 MeV protons were recorded at theta/sub ..cap alpha../ = 20 and 30/sup 0/ in the laboratory frame. The region from 6 to 18 MeV excitation energy of the residual nucleus was carefully studied for possible levels. Evidence for a T = 1 level at E/sub x/ = 8.2 +- 0.2 MeV with a width GAMMA = 2.2 +- 0.2 MeV is reported. No other levels were observed in the present spectra. (AIP)

Comparisons of carcinogenicities of nickel compounds in rats

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

Sunderman, F.W. Jr.; Maenza, R.M.

This study demonstrates marked differences in the incidences of sarcomas in Fischer rats within 2 years after a single im injection of 4 insoluble nickel-containing powders amorphous nickel monosulfide (NiS), nickel subsulfide (..cap alpha..Ni/sub 3/S/sub 2/), partially converted nickel-iron sulfide matte, and metallic nickel. The powders (<2 ..mu..m median particle diameters) were administered in penicillin suspension, and each powder was tested at 2 dosages. Whereas ..cap alpha..Ni/sub 3/S/sub 2/ was highly carcinogenic, amorphous NiS did not induce any tumors. The carcinogenic potency of partially converted nickel-iron sulfide matte was less than ..cap alpha..Ni/sub 3/S/sub 2/ but greater than Ni powder.more » No sarcomas occurred at the injection site in two groups of control rats that received im injections of penicillin or Fe powder. The observed differences in carcinogenic potencies of ..cap alpha..Ni/sub 3/S/sub 2/ and amorphous NiS may provide an experimental approach to elucidate the molecular mechanisms of nickel carcinogenesis.« less

Hydrophobic interactions in complexes of antimicrobial peptides with bacterial polysaccharides.

PubMed

Kuo, Hsin H; Chan, Celine; Burrows, Lori L; Deber, Charles M

2007-06-01

Biofilms of Pseudomonas aeruginosa are responsible for chronic lung infections in cystic fibrosis patients, where they are characterized by overproduction of the exopolysaccharide alginate and are recalcitrant to treatment with conventional antibiotics. Cationic antimicrobial peptides (CAPs) are potential alternatives for the treatment of multi-drug-resistant P. aeruginosa. However, alginate in P. aeruginosa biofilms has been proposed to bind these peptides through hydrophobic interactions, consequently reducing their activity [Chan et al., J Biol Chem 2004; 279: 38749-38754]. Here we perform biophysical analyses of the interactions of alginate with a series of novel peptide antibiotics (alpha-CAPs) of prototypic sequence KK-AAAXAAAAAXAAWAAXAAA-KKKK (where X = Phe, Trp or Leu). The hydrophobic interaction interface in alginate was investigated by examining (i) the effects of polysaccharide composition with respect to D-mannuronate and L-guluronate content; (ii) glycan chain length; (iii) alpha-CAP Trp fluorescence; and (iv) 1-anilinonaphthalene-8-sulfonate fluorescence. The results show that, while M and G residues produce equivalent effects, hydrophobic interactions between alginate and alpha-CAPs require a minimal glycan chain length. Peptide interactions with alginate are deduced to be mediated by hydrophobic microdomains comprised of pyranosyl C-H groups that are inducible upon formation of alpha-CAP-alginate complexes due to charge neutralization between the two species.

Dissimilar effects of chronic treatment with aspirin, flubiprofen and indomethacin on renal prostaglandins

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

Quilley, C.P.; McGiff, J.C.; Quilley, J.

Inhibition of prostaglandin (PG) excretion is not sustained during long-term aspirin administration. The authors compared the effects of 9d treatment of SHR rats with aspirin (A), 200 mg/kg/d s.c., flubiprofen (F), 2.5 mg/kg/12h s.c., and indomethacin (I), 2.5 mg/kg/12 s.c. on excretion of radioimmunoassayable PGE/sub 2/ and PGF/sub 2..cap alpha../. Conversion of 1-(/sup 14/C) arachidonic acid (AA) by renal papillae was also examined. In vehicle-treated control rats (C) PGF/sub 2..cap alpha../ excretion varied from 32.2 +/- 6.2 (mean +/- SEM) to 41.6 +.- 7.3 ng/6h, 3-fold higher than that of PGE/sub 2/. Within 6h of administration all 3 drugs reducedmore » excretion of PGF/sub 2..cap alpha../ and PGE/sub 2/ to less than 20% and 35% of C rats. Although urinary concentrations of PGF/sub 2..cap alpha../ and PGE/sub 2/ in A-treated rats remained depressed, a 2-fold increase in urine volume resulted in excretion rates similar to C rats. In contrast, urine volume in I- and F-treated rats was unaffected while PGF/sub 2..cap alpha../ and PGE/sub 2/ excretion rates in I-treated rats were 50''% of C rats and were also lower than control in F-treated rats. Paradoxically, metabolism of AA to PGs by by renal papillae dissected on day 10, 2-4h after the last drug dose, was markedly inhibited by A (PGF/sub 2..cap alpha../ by 62% and PGE/sub 2/ by 82%), but unaffected by I and F. As the effects of cyclooxygenase inhibitors differ on in vivo and indices of PG production, their intended action should be verified by measuring PG levels in biological fluids.« less

Non-linear vacuum polarization in strong fields

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

Gyulassy, M.

1981-07-01

The Wichmann-Kroll formalism for calculating the vacuum polarization density to first order in ..cap alpha.. but to all orders in Z..cap alpha.. is derived. The most essential quantity is shown to be the electrons Green's function in these calculations. The method of constructing that Green's function in the field of finite radius nuclei is then presented.

Metabolism of. cap alpha. -C/sup 14/-histidine in the intact rat. II. Radioactive excretion products in urine

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

Wolf, G.; Wu, P.H.L.; Heck, W.W.

1956-09-01

The normal metabolic pathways in the intact rat was investigated via the radioactive urinary excretion products following administration of a physiological dose of a radioactive compound such as ..cap alpha..-C/sup 14/-DL-histidine. The major metabolites, except one, excreted in the urine 5 hours after administration of ..cap alpha..-C/sup 14/-DL-histidine were isolated and identified. Glutamic acid and urocanic acids had simlar and low activities, whereas carboxyl-labeled imidazoacetic acid was found to be the principal metabolite with a high level of activity. It was concluded that the main end-product of the catabolism of DL-histidine is imidazoleacetic acid probably formed through imidazolepyruvic acid.

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

Weinstein, L.; Droegemueller, W.; Cornette, J.

A single intra-amniotic injection of (15S)-15 methyl prostaglandin F/sub 2/..cap alpha.. (THAM) was used to induce second trimester abortion in five patients. Serial levels of (15S)-15 methyl prostaglandin F/sub 2/..cap alpha.. were subsequently measured in amniotic fluid and plasma by radioimmunoassay. The slow removal of this drug from the amniotic fluid was documented. Plasma levels of (15S)-15 methyl prostaglandin F/sub 2/..cap alpha.. increased fourfold to sevenfold after clinical rupture of the membranes in three patients, supporting the fact that prostaglandins are well absorbed from the vagina. Because this analogue of prostaglandin can cause marked peripheral bronchoconstriction when administered systemically, itmore » is best to avoid its use in patients with a history of asthma.« less

Self-modulating pressure gauge

DOEpatents

Edwards, D. Jr.; Lanni, C.P.

1979-08-07

An ion gauge is disclosed having a reduced x-ray limit and means for measuring that limit. The gauge comprises an ion gauge of the Bayard-Alpert type having a short collector and having means for varying the grid-collector voltage. The x-ray limit (i.e. the collector current resulting from x-rays striking the collector) may then be determined by the formula: I/sub x/ = ..cap alpha..I/sub l/ - I/sub h//..cap alpha.. - l where: I/sub x/ = x-ray limit, I/sub l/ and I/sub h/ = the collector current at the lower and higher grid voltage respectively; and, ..cap alpha.. = the ratio of the collector current due to positive ions at the higher voltage to that at the lower voltage.

Internode length in Pisum. Gene na may block gibberellin synthesis between ent-7. cap alpha. -hydroxykaurenoic acid and biggerellin A/sub 12/-aldehyde. [Pisum sativum

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

Ingram, T.J.; Reid, J.B.

1987-04-01

The elongation response of the gibberellin (GA) deficient genotypes na, ls, and lh of peas (Pisum sativum L.) to a range of GA-precursors was examined. Plants possessing gene na did not respond to precursors in the GA biosynthetic pathway prior to GA/sub 12/-aldehyde. In contrast, plants possessing lh and ls responded as well as wild-type plants (dwarfed with AMO-1618) to these compounds. The results suggest that GA biosynthesis is blocked prior to ent-kaurene in the lh and ls mutants and between ent-7..cap alpha..-hydroxykaurenoic acid and GA/sub 12/-aldehyde in the na mutant. Feeds of ent(/sup 3/H)kaurenoic acid and (/sup 2/H)GA/sub 12/-aldehydemore » to a range of genotypes supported the above conclusions. The na line WL1766 was shown by gas chromatography-mass spectrometry (GC-MS) to metabolize(/sup 2/H)GA/sub 12/-aldehyde to a number of (/sup 2/H)C/sub 19/-GAs including GA/sub 1/. However, there was no indication in na genotypes for the metabolism of ent-(/sup 3/H)kaurenoic acid to these GAs. In contrast, the expanding shoot tissue of all Na genotypes examined metabolized ent-(/sup 3/H)kaurenoic acid to radioactive compounds that co-chromatographed with GA/sub 1/, GA/sub 8/, GA/sub 20/, and GA/sub 29/. However, insufficient material was present for unequivocal identification of the metabolites. The radioactive profiles from HPLC of extracts of the node treated with ent-(/sup 3/H)kaurenoic acid were similar for both Na and na plants and contained ent-16..cap alpha..,17-dihydroxykaurenoic acid and ent-6..cap alpha..,7..cap alpha..,16..beta..,17-tetrahydroxykaurenoic acid (both characterized by GC-MS), suggesting that the metabolites arose from side branches of the main GA-biosynthetic pathway. Thus, both Na and na plants appear capable of ent-7..cap alpha..-hydroxylation.« less

On capturing the grain-scale elastic and plastic anisotropy of alpha-Ti with spherical nanoindentation and electron back-scattered diffraction

DOE PAGES

Weaver, Jordan S.; Priddy, Matthew W.; McDowell, David L.; ...

2016-09-01

Here, spherical nanoindentation combined with electron back-scattered diffraction has been employed to characterize the grain-scale elastic and plastic anisotropy of single crystal alpha-Ti of two different compositions (in two different titanium alloys). Data analyses protocols needed to reliably extract the desired properties of interest are extended and demonstrated in this paper. Specifically, the grain-scale mechanical response is extracted in the form of indentation stress-strain curves for commercially pure (CP-Ti) alpha-Ti and alloyed (Ti-64) titanium from measurements on polycrystalline samples. The results are compared with responses of single crystals and nanoindentation tests (hardness and modulus) from the literature, and the measuredmore » indentation moduli are validated using crystal-elastic finite element simulations. The results obtained in this study show that (i) it is possible to characterize reliably the elastic and plastic anisotropy of alpha-Ti (hcp) of varying alloying contents with spherical nanoindentation stress-strain curves, (ii) the indentation modulus of alpha-Ti-64 is 5–10% less than CP-Ti, and (iii) the indentation yield strength of alpha-Ti-64 is 50–80% higher than CP-Ti.« less

Copernicus observations of Betelgeuse and Antares

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

Bernat, A.P.; Lambert, D.L.

1975-01-01

Copernicus observations of the M-supergiants, ..cap alpha.. Ori and ..cap alpha.. Sco, are presented. The Mg II H and K resonance lines are strongly in emission in both stars. The K line is highly asymmetric in both stars but the H line is symmetric. Upper limits for several other resonance lines are given for ..cap alpha.. Ori. The possibility is explored that the K line asymmetry is caused by overlying resonance lines of Mn I and Fe I formed in the cool circumstellar gas shells around these stars. Observations of the Mn I 4030--4033 A lines are used to showmore » that circumstellar shell absorption is too weak to explain the asymmetry. It is suggested that the absorption occurs in a cool turbulent region between the base of the circumstellar shell and the top of the chromosphere. (auth)« less

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

Walker, T.E.; Han, C.H.; Kollman, V.H.

/sup 13/C NMR of isotopically enriched metabolites has been used to study the metabolism of Microbacterium ammoniaphilum, a bacterium which excretes large quantities of L-glutamic acid into the medium. Biosynthesis from 90% (1-/sup 13/C) glucose results in relatively high specificity of the label, with (2,4-/sup 13/C/sub 2/) glutamate as the major product. The predominant biosynthetic pathway for synthesis of glutamate from glucose was determined to be the Embden Meyerhof glycolytic pathway followed by P-enolpyruvate carboxylase and the first third of the Krebs cycle. Different metabolic pathways are associated with different correlations in the enrichment of the carbons, reflected in themore » spectrum as different /sup 13/C-/sup 13/C scalar multiplet intensities. Hence, intensity and /sup 13/C-/sup 13/C multiplet analysis allows quantitation of the pathways involved. Although blockage of the Krebs cycle at the ..cap alpha..-ketoglutarate dehydrogenase step is the basis for the accumulation of glutamate, significant Krebs cycle activity was found in glucose grown cells, and extensive Krebs cycle activity in cells metabolizing (1-/sup 13/C) acetate. In addition to the observation of the expected metabolites, the disaccharide ..cap alpha..,..cap alpha..-trehalose and ..cap alpha..,..beta..-glucosylamine were identified from the /sup 13/C NMR spectra.« less

DEAD ZONE IN THE POLAR-CAP ACCELERATOR OF PULSARS

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

Chen, Alexander Y.; Beloborodov, Andrei M.

We study plasma flows above pulsar polar caps using time-dependent simulations of plasma particles in the self-consistent electric field. The flow behavior is controlled by the dimensionless parameter {alpha} = j/c{rho}{sub GJ}, where j is the electric current density and {rho}{sub GJ} is the Goldreich-Julian charge density. The region of the polar cap where 0 < {alpha} < 1 is a {sup d}ead zone{sup -}in this zone, particle acceleration is inefficient and pair creation is not expected even for young, rapidly rotating pulsars. Pulsars with polar caps near the rotation axis are predicted to have a hollow-cone structure of radiomore » emission, as the dead zone occupies the central part of the polar cap. Our results apply to charge-separated flows of electrons (j < 0) or ions (j > 0). In the latter case, we consider the possibility of a mixed flow consisting of different ion species, and observe the development of two-stream instability. The dead zone at the polar cap is essential for the development of an outer gap near the null surface {rho}{sub GJ} = 0.« less

Breakup processes in heavy-ion induced reactions

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

Udagawa, T.; Tamura, T.; Shimoda, T.

1979-11-01

Cross sections for breakup of /sup 20/Ne into /sup 16/O and ..cap alpha.. during scattering from /sup 40/Ca were calculated in terms of the distorted-wave Born approximation. The inclusive /sup 16/O cross section observed in the /sup 40/Ca(/sup 20/Ne,/sup 16/O) reaction was then found to be fitted very well by the sum of this breakup contribution and that of the ..cap alpha..-transfer reaction calculated in our previous work.

Dielectronic satellite spectra of hydrogen-like titanium (Ti XXII)

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

Bitter, M.; von Goeler, S.; Cohen, S.

High resolution spectra of the Ly ..cap alpha../sub 1/ and Ly ..cap alpha../sub 2/ lines of hydrogenlike titanium, TiXXII, and the associated dielectronic satellites which are due to transitions 1snl-2pnl with n greater than or equal to 2, have been observed from tokamak discharges with auxiliary ion cyclotron heating (ICRH) with central electron temperatures of 2 keV and central electron densities of 8 x 10/sup 13/ cm/sup -3/ on the Princeton Large Torus (PLT). The data have been used for a detailed comparison with theoretical predictions based on the Z - expansion method and Hartree - Fock calculations. The resultsmore » obtained with the Z - expansion method are in excellent agreement with the observed spectral data except for minor discrepancies between the theoretical and experimental wavelengths of 0.0003 A for the n = 2 satellites and of 0.0001 A for the separation of the Ly ..cap alpha../sub 1/ and Ly ..cap alpha../sub 2/ lines. Very good agreement with the experimental data is also obtained for the results from the Hartree - Fock calculations though somewhat larger discrepancies (approx. = 0.0009 A) exist between experimental and theoretical wavelengths which are systematically too small. The observed spectra are used for diagnosis of the central ion and electron temperatures of the PLT discharges and for a measurement of the dielectronic recombination rate coefficient of TiXXII.« less

Isolation of tungsten and tantalum isotopes without supports from. cap alpha. -particle-irradiated hafnium targets

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

Gasita, S.M.; Iota, B.Z.; Malachkov, A.G.

1985-11-01

An extraction procedure has been developed for successive isolation of tungsten (/sup 178/W and /sup 181/W) and tantalum (/sup 179/Ta and /sup 182/Ta) isotopes without supports from ..cap alpha..particle-irradiated hafnium targets. The target, irradiated on a cyclotron, is dissolved in hydrofluoric acid. Tantalum isotopes are extracted with tributyl phosphate (TBP) from 1-5 M HF and are then reextracted with a 1:1 ammonia solution, and hydrofluoric acid is removed by heating. Tungsten isotopes are extracted with a chloroform solution or N-benzoyl-N-phenylhydroxylamine (BPHA) from 11-12 M H/sub 2/SO/sub 4/ or ..cap alpha..-benzoin oxime from 4.5-5.5 M H/sub 2/SO/sub 4/ and are thenmore » reextracted with a l:l ammonia solution. The yield of tungsten isotopes is not less than 95%, and the content of radioactive impurities of other isotopes is not more than 0.1%.« less

Description of alpha-nucleus interaction cross sections for cosmic ray shielding studies

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1993-01-01

Nuclear interactions of high-energy alpha particles with target nuclei important for cosmic ray studies are discussed. Models for elastic, quasi-elastic, and breakup reactions are presented and compared with experimental data. Energy-dependent interaction cross sections and secondary spectra are presented based on theoretical models and the limited experimental data base.

Selective inhibition by chloramphenicol of pregnenolone-16. cap alpha. -carbonitrile-inducible rat liver cytochrome P-450 isozymes

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

Graves, P.E.; Kaminsky, L.S.; Halpert, J.

Pregnenolone-16 ..cap alpha..-carbonitrile (PCN) has been shown to induce, in male rats, cytochrome P-450 isozymes responsible for the formation of R-10-hydroxywarfarin and R-dehydrowarfarin. Antibodies to the major PCN-inducible isozyme (PB/PCN-E) inhibit both activities in microsomal preparations. Recently the authors have shown that PCN treatment of female rats also induces the formation of both R-warfarin metabolites. However, in both sexes chloramphenicol (CAP) treatment selectively inhibits only the rate of formation of the R-dehydrowarfarin. A decrease in microsomal P-450 content occurs after in vivo administration of CAP to PCN-treated rats of both sexes. This is in contrast to the lack of effectmore » of CAP on P-450 levels in phenobarbital-treated rats. Covalent binding of /sup 14/C-CAP to microsomal protein in vitro was increased 3 to 4-fold following PCN treatment. Chromatographic evidences suggests the presence of at least two PCN-induced isozymes of similar molecular weights in both male and female rat liver microsomes. These data are consistent with the multiplicity of PCN-inducible P-450 in rat liver.« less

Chromosomal aberrations and delays in cell progression induced by x-rays in Tradescantia clone 02 meristems

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

Geard, C.R.

1983-01-01

In root meristems of Tradescantia clone 02 (developed by Sparrow and his colleagues for mutation studies), X-rays interfere with the progression of cells through the cell cycle and induce chromosomal aberrations in a dose-dependent manner consistent with linear-quadratic kinetics. Sequential mitotic cell accumulations after irradiation indicate that sensitivity to aberration induction is probably greatest in cells from late S to early G2, with chromatid interchanges the most frequent aberration type and all aberrations consistent with initiation from the interaction between two lesions. The ratio of the coefficients in the linear (..cap alpha..) and the quadratic (..beta..) terms (..cap alpha../..beta..) ismore » equal to the dose average of specific energy produced by individual particles in the site where interaction takes place. The ratio ..cap alpha../..beta.. for chromosomal aberrations is similar to that previously found for X-ray-induced mutation in Tradescantia stamen hairs, supporting the proposal that radiation-induced mutational events are due to chromosomal aberrations with interaction distances of about 1..mu..m. Abrahamson and co-workers have noted that both ..cap alpha../..beta.. ratios appear to be related to nuclear target size and are similar for chromosomal and mutational endpoints in the same organism. These findings support this concept; however, it is apparent that any situation which diminishes yield at high doses (e.g., mitotic delay) will probably affect the ..beta.. component. 23 references, 5 figures, 2 tables.« less

Chromosomal aberrations and delays in cell progression induced by x-rays in Tradescantia clone 02 meristems

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

Geard, C.R.

1983-01-01

In root meristems of Tradescantia clone 02 (developed by Sparrow and his colleagues for mutation studies), X-rays interfere with the progression of cells through the cell cycle and induce chromosomal aberrations in a dose-dependent manner consistent with linear-quadratic kinetics. Sequential mitotic cell accumulations after irradiation indicate that sensitivity to aberrration induction is probably greatest in cells from late S to early G2, with chromatid interchanges the most frequent aberration type and all aberrations consistent with intiation from the interaction between two lesions. The ratio of the coefficients in the linear (..cap alpha..) and the quadratic (..beta..) terms (..cap alpha../..beta..) ismore » equal to the dose average of specific energy produced by individual particles in the site where interaction takes place. The ratio ..cap alpha../..beta.. for chromosomal aberrations is similar to that previously found for X-ray-induced mutation in Tradescantia stamen hairs, supporting the proposal that radiation-induced mutational events are due to chromosomal aberrations with interaction distances of about 1 ..mu..m. Abrahmson and co-workers have noted that both ..cap alpha../..beta.. ratios appear to be related to nuclear target size and are similar for chromosomal and mutational endpoints in the same organism. These findings support this concept; however, it is apparent that any situation which diminishes yield at high doses (e.g., mitotic delay) will primarily affect the ..beta.. component, resulting in low assessments of interaction site diameters.« less

Exact near-onset analysis of the spin-density-wave instability in ferromagnetic superconductors: The linearly polarized state

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

Hu, C.

1984-09-01

Using an approach similar to Abvikosov's theory of the vortex state near H/sub c/2, we have performed an exact, near-onset analysis of a spin-density-wave instability leading to the ''linearly polarized state'' of Greenside et al. in ferromagnetic superconductors. The approach is based on a generalized Ginzburg-Landau theory for such materials, as formulated by Blount and Varma. Two models have been considered. In the (..cap alpha..,..beta..) model, where the bulk magnetic energy is taken to be (1/2)..cap alpha../sub m/M/sup 2/+(1/4)..beta../sub m/M/sup 4/, we find the transition to be second order, and obtain explicit formulas for various physical quantities to leading ordermore » in the deviation from onset. We have also rigorously analyzed the most favored spatial structure just below onset, among all possibilities allowed by the instability, and have concluded that a plane-wave-like structure is favored in a physical limit considered. In the (..cap alpha..,..gamma..) model, where the bulk magnetic energy is taken to be (1/2)..cap alpha../sub m/M/sup 2/+(1/6)..gamma../sub m/M/sup 6/ as is supported by recent experiments for ErRh/sub 4/B/sub 4/, we find the transition to be first order. This approach is then confined to an unphysical branch, which does not permit us to calculate various physical quantities on the physical branch.« less

Drosophila Casein Kinase I Alpha Regulates Homolog Pairing and Genome Organization by Modulating Condensin II Subunit Cap-H2 Levels

PubMed Central

Nguyen, Huy Q.; Nye, Jonathan; Buster, Daniel W.; Klebba, Joseph E.; Rogers, Gregory C.; Bosco, Giovanni

2015-01-01

The spatial organization of chromosomes within interphase nuclei is important for gene expression and epigenetic inheritance. Although the extent of physical interaction between chromosomes and their degree of compaction varies during development and between different cell-types, it is unclear how regulation of chromosome interactions and compaction relate to spatial organization of genomes. Drosophila is an excellent model system for studying chromosomal interactions including homolog pairing. Recent work has shown that condensin II governs both interphase chromosome compaction and homolog pairing and condensin II activity is controlled by the turnover of its regulatory subunit Cap-H2. Specifically, Cap-H2 is a target of the SCFSlimb E3 ubiquitin-ligase which down-regulates Cap-H2 in order to maintain homologous chromosome pairing, chromosome length and proper nuclear organization. Here, we identify Casein Kinase I alpha (CK1α) as an additional negative-regulator of Cap-H2. CK1α-depletion stabilizes Cap-H2 protein and results in an accumulation of Cap-H2 on chromosomes. Similar to Slimb mutation, CK1α depletion in cultured cells, larval salivary gland, and nurse cells results in several condensin II-dependent phenotypes including dispersal of centromeres, interphase chromosome compaction, and chromosome unpairing. Moreover, CK1α loss-of-function mutations dominantly suppress condensin II mutant phenotypes in vivo. Thus, CK1α facilitates Cap-H2 destruction and modulates nuclear organization by attenuating chromatin localized Cap-H2 protein. PMID:25723539

Antisymmetrization effects and the form factor of the real part of the. cap alpha. -nucleus potential

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

Majka, Z.; Budzanowski, A.; Grotowski, K.

1978-07-01

Antisymmetrization effects in the ..cap alpha..-nucleus interaction are investigated on the basis of a microscopic model in an one nucleon exchange approximation. It influences the form factor, increasing the halfway radius and decreasing the diffuseness as compared with the direct term of the potential only. Antisymmetrization preserves the shape of the potential which can be parametrized by a Woods-Saxon squared form. The phenomenological potential with the energy independent form factor of the above shape fits experimental data in a wide energy region.

Cross sections and differential spectra for reactions of 2-20 MeV neutrons of /sup 27/Al

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

Blann, M.; Komoto, T.T.

1988-01-01

This report summarizes product yields, secondary n,p and ..cap alpha.. spectra, and ..gamma..-ray spectra calculated for incident neutrons of 2-20 MeV on /sup 27/Al targets. Results are all from the code ALICE, using the version ALISO which does weighting of results for targets which are a mix of isotopes. Where natural isotopic targets are involved, yields and n,p,..cap alpha.. spectra will be reported weighted over isotopic yields. Gamma-ray spectra, however, will be reported for the most abundant isotope.

{alpha}+{alpha} scattering reexamined in the context of the Sao Paulo potential

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

Chamon, L. C.; Gasques, L. R.; Carlson, B. V.

2011-03-15

We have analyzed a large set of {alpha}+{alpha} elastic scattering data for bombarding energies ranging from 0.6 to 29.5 MeV. Because of the complete lack of open reaction channels, the optical interaction at these energies must have a vanishing imaginary part. Thus, this system is particularly important because the corresponding elastic scattering cross sections are very sensitive to the real part of the interaction. The data were analyzed in the context of the velocity-dependent Sao Paulo potential, which is a successful theoretical model for the description of heavy-ion reactions from sub-barrier to intermediate energies. We have verified that, even inmore » this low-energy region, the velocity dependence of the model is quite important for describing the data of the {alpha}+{alpha} system.« less

Molecular versus squared Woods-Saxon α-nucleus potentials in the 27Al(α, t)28Si reaction

NASA Astrophysics Data System (ADS)

Abdullah, M. N. A.; Das, S. K.; Tariq, A. S. B.; Mahbub, M. S.; Mondal, A. S.; Uddin, M. A.; Basak, A. K.; Gupta, H. M. Sen; Malik, F. B.

2003-06-01

The differential cross-section of the 27Al(alpha, t)28Si reaction for 64.5 MeV incident energy has been reanalysed in DWBA with full finite range using a squared Woods-Saxon (Michel) alpha-nucleus potential with the modified value of the depth parameter alpha = 2.0 as reported in a comment article by Michel and Reidemeister. This new value produces significant improvement in fitting the data of the reaction with its overall performance, in some cases, close to that previously observed for the molecular potential. Although the non-monotonic shallow molecular potential with a soft repulsive core and the Michel potentials produce the same quality fits to the elastic scattering and non-elastic processes, they are not phase equivalent. The two types of potential produce altogether different cross-sections, particularly at large reaction angles. The importance of the experimental cross-sections at large angles for both elastic scattering and non-elastic processes is elucidated.

Passive stiffness of pressure-induced hypertrophied cat myocardium.

PubMed

Williams, J F; Potter, R D

1981-07-01

The effect of myocardial hypertrophy on passive stiffness was determined from the stress (sigma)-strain relationship of right ventricular papillary muscles from 18 pulmonary artery-banded and 21 non-banded cats. By use of Lagrangian strain, (1-lo)lo is initial muscle length, and instantaneous stress elastic constants beta and alpha were calculated from the equation sigma = alpha(ebeta epsilon - 1). Elastic stiffness (d sigma/d epsilon) was determined from the formula d sigma/d epsilon = beta alpha + alpha beta. Banding produced an average increase in RV mass of 70%. Beta averaged 14.2 +/- 0.9 (SEM) and 16.0 +/- 0.8 in the non-hypertrophied and hypertrophied muscles, respectively (NS). However, elastic stiffness was significantly greater in hypertrophied muscles over the entire stress range. Contractile function varied widely among hypertrophied muscles but was not related to changes in stiffness. Thus, moderate degrees of pressure-induced hypertrophy are associated with a modest increase in the passive stiffness properties of the muscle, independent of changes in contractile function.

Separation of anionic oligosaccharides by high-performance liquid chromatography

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

Green, E.D.; Baenziger, J.U.

1986-10-01

The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since themore » latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (..cap alpha..2,3 vs ..cap alpha..2,6) and/or location of ..cap alpha..2,3- and ..cap alpha..2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties.« less

Biomechanical investigation of titanium elastic nail prebending for treating diaphyseal long bone fractures.

PubMed

Chen, Yen-Nien; Lee, Pei-Yuan; Chang, Chih-Wei; Ho, Yi-Hung; Peng, Yao-Te; Chang, Chih-Han; Li, Chun-Ting

2017-03-01

This study numerically investigated the deformation of titanium elastic nails prebent at various degrees during implantation into the intramedullary canal of fractured bones and the mechanism by which this prebending influenced the stability of the fractured bone. Three degrees of prebending the implanted portions of the nails were used: equal to, two times, and three times the diameter of the intramedullary canal. Furthermore, a simulated diaphyseal fracture with a 5-mm gap was created in the middle shaft portion of the bone fixed with two elastic nails in a double C-type configuration. End caps were simulated using a constraint equation. To confirm that the simulation process is able to present the mechanical response of the nail inside the intramedullary, an experiment was conducted by using sawbone for validation. The results indicated that increasing the degrees of nail prebending facilitated straightening the nails against the inner aspect of canal after implantation, with increase in stability under torsion. Furthermore, reducing nail prebending caused a larger portion of the nails to move closer to the loading site and center of bone after implantation; the use of end caps prevented the nail tips from collapsing and increased axial stability. End cap use was critical for preventing the nail tips from collapsing and for increasing the stability of the nails prebent at a degree equal to the diameter of the canal with insufficient frictional force between the nail and canal. Therefore, titanium elastic nail prebending in a double C-type configuration with a degree three times the diameter of the canal represents a superior solution for treating transverse fractures without a gap, whereas that with a degree equal to the diameter of the intramedullary canal and combined with end cap use represents an advanced solution for treating comminuted fractures in a diaphyseal long bone fracture.

Temperature dependence of single-crystal elastic constants of flux-grown alpha-GaPO(4).

PubMed

Armand, P; Beaurain, M; Rufflé, B; Menaert, B; Papet, P

2009-06-01

The lattice parameter change with respect to temperature (T) has been measured using high-temperature powder X-ray diffraction techniques for high-temperature flux-grown GaPO(4) single crystals with the alpha-quartz structure. The lattice and the volume linear thermal expansion coefficients in the temperature range 303-1173 K were computed from the X-ray data. The percentage linear thermal expansions along the a and c axes at 1173 K are 1.5 and 0.51, respectively. The temperature dependence of the mass density rho of flux-grown GaPO(4) single crystals was evaluated using the volume thermal expansion coefficient alpha(V)(T) = 3.291 x 10(-5) - 2.786 x 10(-8) [T] + 4.598 x 10(-11)[T](2). Single-crystal high-resolution Brillouin spectroscopy measurements have been carried out at ambient pressure from 303 to 1123 K to determine the elastic constants C(IJ) of high-temperature flux-grown GaPO(4) material. The single-crystal elastic moduli were calculated using the sound velocities via the measured Brillouin frequency shifts Deltanu(B). These are, to our knowledge, the highest temperatures at which single-crystal elastic constants of alpha-GaPO(4) have been measured. Most of the room-temperature elastic constant values measured on flux-grown GaPO(4) material are higher than the ones found for hydrothermally grown GaPO(4) single crystals. The fourth-order temperature coefficients of both the Brillouin frequency shifts T(nuB)((n)) and the single-crystal elastic moduli T(C(IJ))((n)) were obtained. The first-order temperature coefficients of the C(IJ) are in excellent agreement with previous reports on low-temperature hydrothermally grown alpha-GaPO(4) single crystals, while small discrepancies in the higher-order temperature coefficients are observed. This is explained in terms of the OH content in the GaPO(4) network, which is an important parameter in the crystal thermal behavior.

Tubulin chaperone E binds microtubules and proteasomes and protects against misfolded protein stress.

PubMed

Voloshin, Olga; Gocheva, Yana; Gutnick, Marina; Movshovich, Natalia; Bakhrat, Anya; Baranes-Bachar, Keren; Bar-Zvi, Dudy; Parvari, Ruti; Gheber, Larisa; Raveh, Dina

2010-06-01

Mutation of tubulin chaperone E (TBCE) underlies hypoparathyroidism, retardation, and dysmorphism (HRD) syndrome with defective microtubule (MT) cytoskeleton. TBCE/yeast Pac2 comprises CAP-Gly, LRR (leucine-rich region), and UbL (ubiquitin-like) domains. TBCE folds alpha-tubulin and promotes alpha/beta dimerization. We show that Pac2 functions in MT dynamics: the CAP-Gly domain binds alpha-tubulin and MTs, and functions in suppression of benomyl sensitivity of pac2Delta mutants. Pac2 binds proteasomes: the LRR binds Rpn1, and the UbL binds Rpn10; the latter interaction mediates Pac2 turnover. The UbL also binds the Skp1-Cdc53-F-box (SCF) ubiquitin ligase complex; these competing interactions for the UbL may impact on MT dynamics. pac2Delta mutants are sensitive to misfolded protein stress. This is suppressed by ectopic PAC2 with both the CAP-Gly and UbL domains being essential. We propose a novel role for Pac2 in the misfolded protein stress response based on its ability to interact with both the MT cytoskeleton and the proteasomes.

Stability analysis of a reinforced carbon carbon shell

NASA Technical Reports Server (NTRS)

Agan, W. E.; Jordan, B. M.

1977-01-01

This paper presents the development of a stability analysis for the nose cap of the NASA Space Shuttle Orbiter. Stability is evaluated by the differential stiffness analysis of the NASTRAN finite-element computer code, addressing those nonstandard characteristics in the nose cap such as nonuniform curvature, asymmetrical and nonuniform loads, support fixity, and various combinations of membrane and bending stresses. A full-sized nose cap, thinner than production, was statically tested and stability analyzed. The failing load level correlated to within 30%. The region and mode of buckling that occurred during test was accurately predicted by analysis. The criterion for predicting instability is based on the behavior of the nonlinear deflections. The deflections are nonlinear elastic in that the stresses are well within the elastic range of the material, but the geometry-load relationship produces nonlinear deflections. The load-deflection relationship is well defined by differential stiffness analysis up to the zero-slope portion of the curve, the point of neutral stability or where the shell 'snaps through' just prior to general instability.

Calculated half-lives and kinetic energies for spontaneous emission of heavy ions from nuclei

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

Poenaru, D.N.; Greiner, W.; Depta, K.

The most probable decays by spontaneous emission of heavy ions are listed for nuclides with Z = 47--106 and total half-lives>1 ..mu..sec. Partial half-lives, branching ratios relative to ..cap alpha.. decay, kinetic energies, and Q values are estimated by using the analytical superasymmetric fission model, a semiempirical formula for those ..cap alpha..-decay lifetimes which have not been measured, and the new Wapstra--Audi mass tables. Numerous ''stable'' nuclides with Z>40 are found to be metastable with respect to the new decay modes. The current experimental status is briefly reviewed.

Algal succession and chronosequences on abandoned mine spoils

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

Shubert, L.E.; Starks, T.L.

1978-06-01

Soils were collected from spoil material aged 0 to 45 years. The soils were analyzed for the presence of algal species, chlorophyll ..cap alpha.., major cations, anions and trace elements. There was a gradual increase in the number of algal species and chlorophyll ..cap alpha.. from 1 year old spoils to adjacent unmined natural sites. A total of 41 algal species were identified from all sites. Several species were only found at the unmined sites and they may represent a stable algal community. Results of a statistical analysis on the litho- and chronosequence of the soils will be discussed.

Biosynthesis of ketomycin. (II) biomimetic model for beta-lactamase catalysis: host-guest interactions in cyclodextrin-penicillin inclusion complex

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

Mak, H.W.

The antibiotic ketomycin is formed from shikimic acid via chorismic acid and prephenic acid. Phenylalanine and 2',5'-dihydrophenylalanine derived from shikimic acid are not intermediates in the biosynthesis. Degradation of ketomycin derived from (1,6-/sup 14/C)shikimic acid showed that prephenic acid is converted into ketomycin with stereospecific discrimination between the two enantiotopic edges of the ring, the pro-S-R edge giving rise to the C-2', C-3' side of the cyclohexane ring of ketomycin. The resistance of pathogenic bacteria to the action of ..beta..-lactam antibiotics is mainly ascribed to their ability to produce ..beta..-lactamase to cleave the ..beta..-lactam ring. It is essential to understandmore » the molecular nature of ..beta..-lactamase-penicillin recognition for designing and formulating more effective ..beta..-lactam antibiotics. A biomimetic study of ..beta..-lactamase is therefore initiated. To meet the requirements of hydrophobic and serine protease characteristics of ..beta..-lactamase, ..cap alpha..-cyclodextrin is chosen as a biomimetic model for ..beta..-lactamase. The structural specificity and the chemical dynamics of ..cap alpha..-cyclodextrin-phenoxymethyl penicillin inclusion complex in solid state and in solution have been determined by IR and NMR spectroscopy. The spectral results strongly indicate that the phenyl portion of the phenoxymethyl penicillin forms a stable inclusion complex with the hydrophobic cavity of ..cap alpha..-cyclodextrin in solution as well as in the solid state. Kinetic studies followed by /sup 1/HNMR and HPLC analyses under alkaline condition have shown that the ..cap alpha..-cyclodextrin mimics the catalytic function of serine of ..beta..-lactamase in the stereospecific hydrolysis of the ..beta..-lactam ring of phenoxymethyl penicillin.« less

Depth-Dependent Defect Studies Using Coherent Acoustic Phonons

DTIC Science & Technology

2014-09-29

using CAP waves as an active moving interface to induce local changes in electric, acoustic , and optical properties. This is able to generate ultrafast...the elastic strain component [6]. b) Modification of the crystal lattice due to transient strain caused by the coherent acoustic phonon wave . The...opto-electronic properties of materials. We are also using CAP waves as an active moving interface to induce local changes in electric, acoustic , and

[Cytokine changes in community-acquired pneumonia in elderly and intervention of traditional Chinese medicine].

PubMed

Ye, Shanghe; Gong, Guolang; Zheng, Haiwen; Hu, Guohua; Xia, Tao

2010-06-01

To make a study of the cytokine changes in community-acquired pneumonia (CAP) in the elderly and the intervention of traditional Chinese medicine that can clear away the lung-heat and dissipate blood stasis (Qingfeihuayu soup). The 82 cases with CAP in the elderly were divided at random into two treatment group and control group. Based on heteropathy, the treatment group was given Qingfeihuayu soup two times a day. The control group was given Rocephin 2 g once daily for 7 days. The clinical effect and the changes in TNF-alpha, IL-6 and IL-10 were observed before and after the treatment. A healthy group was also set up. Before treatment, IL-6 and TNF-alpha in both groups were higher than the healthy group (P < 0.01) and IL-10 lower than the healthy group (P < 0.01). After treatment, IL-6 and TNF-alpha in both groups decreased (P < 0.01) while IL-10 in treatment group increased. There existed a great difference compared with the control group (P < 0.01). The total effective rate in the treatment group is 92.50% while the control group is 85.71%. thus have a great difference (P < 0.05). During the process of the development of CAP in the elderly, there existed the phenomenon of the excessive release of TNF-alpha, IL-6 and the too much inhibition of IL-10. The unbalance of TNF-alpha, IL-6, IL-10 can be a monitoring index reflecting the severity of the disease. The Chinese medicine Qingfeihuayu soup has obviously have regulating and clinical effect.

Results from the Crystal Ball at DORIS II

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

Gaiser, J.E.

1983-10-01

Results are presented from studies of the inclusive photon spectra in hadronic decays of the UPSILON' and UPSILON and the exclusive channel UPSILON' ..-->.. ..gamma gamma..UPSILON ..-->.. ..cap alpha cap alpha..l/sup +/l/sup -/, by the Crystal Ball detector at DORIS II. We measure two signals in the UPSILON' ..-->.. ..gamma.. + anything inclusive channel at E(..gamma..) == 108.3 +- 0.9 +- 3.0 MeV and at E(..gamma..) == 127.5 +- 1.2 +- 4.0 MeV. Branching ratios obtained for these signals are: BR(UPSILON' ..-->.. ..gamma..(108) + anything) == (6.3 +- 1.3 +- 1.4)% BR(UPSILON' ..-->.. ..gamma..(128) + anything) == (6.0 +- 1.3more » +- 1.4)%.« less

MFTF-. cap alpha. + T progress report

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

Nelson, W.D.

1985-04-01

Early in FY 1983, several upgrades of the Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory (LLNL) were proposed to the fusion community. The one most favorably received was designated MFTF-..cap alpha..+T. The engineering design of this device, guided by LLNL, has been a principal activity of the Fusion Engineering Design Center during FY 1983. This interim progress report represents a snapshot of the device design, which was begun in FY 1983 and will continue for several years. The report is organized as a complete design description. Because it is an interim report, some parts are incomplete; theymore » will be supplied as the design study proceeds. As described in this report, MFTF-..cap alpha..+T uses existing facilities, many MFTF-B components, and a number of innovations to improve on the physics parameters of MFTF-B. It burns deuterium-tritium and has a central-cell Q of 2, a wall loading GAMMA/sub n/ of 2 MW/m/sup 2/ (with a central-cell insert module), and an availability of 10%. The machine is fully shielded, allows hands-on maintenance of components outside the vacuum vessel 24 h after shutdown, and has provisions for repair of all operating components.« less

Modeling proton and alpha elastic scattering in liquid water in Geant4-DNA

NASA Astrophysics Data System (ADS)

Tran, H. N.; El Bitar, Z.; Champion, C.; Karamitros, M.; Bernal, M. A.; Francis, Z.; Ivantchenko, V.; Lee, S. B.; Shin, J. I.; Incerti, S.

2015-01-01

Elastic scattering of protons and alpha (α) particles by water molecules cannot be neglected at low incident energies. However, this physical process is currently not available in the "Geant4-DNA" extension of the Geant4 Monte Carlo simulation toolkit. In this work, we report on theoretical differential and integral cross sections of the elastic scattering process for 100 eV-1 MeV incident protons and for 100 eV-10 MeV incident α particles in liquid water. The calculations are performed within the classical framework described by Everhart et al., Ziegler et al. and by the ICRU 49 Report. Then, we propose an implementation of the corresponding classes into the Geant4-DNA toolkit for modeling the elastic scattering of protons and α particles. Stopping powers as well as ranges are also reported. Then, it clearly appears that the account of the elastic scattering process in the slowing-down of the charged particle improves the agreement with the existing data in particular with the ICRU recommendations.

Scatter of elastic waves by a thin flat elliptical inhomogeneity

NASA Technical Reports Server (NTRS)

Fu, L. S.

1983-01-01

Elastodynamic fields of a single, flat, elliptical inhomogeneity embedded in an infinite elastic medium subjected to plane time harmonic waves are studied. Scattered displacement amplitudes and stress intensities are obtained in series form for an incident wave in an arbitrary direction. The cases of a penny shaped crack and an elliptical crack are given as examples. The analysis is valid for alpha a up to about two, where alpha is longitudinal wave number and a is a typical geometric parameter.

Muscarinic cholinergic and alpha/sub 1/ adrenergic receptors in murine atria: phosphatidylinositol breakdown and receptor interaction

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

Scherer, R.W.

Upon stimulation of muscarinic cholinergic receptors, there is a decrease in the force of contraction rate of firing in heart, while stimulation of ..cap alpha.. adrenergic receptors causes an increase in the force of contraction with no change in the heart rate. Yet both receptors stimulate the breakdown of phosphatidylinositol (PI). Therefore, the breakdown of PI was examined to determine how the process differed between the two receptor systems. Murine atria, prelabelled with (/sup 3/H)inositol, were stimulated with the muscarinic cholinergic agonists, carbamylcholine (CARB), and oxotremorine (OXO); and with the ..cap alpha.. adrenergic agonists, norepinephrine (NE) and phenylephrine (PE); eithermore » singly or in combination. Breakdown of PI was assessed by measurement of individual inositol phosphates by anion exchange chromatography. Binding of CARB to atrial muscarinic receptors was measured by competition with (/sup 3/H)quinuclidinyl benzilate.« less

Avalanche proton-boron fusion based on elastic nuclear collisions

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

Eliezer, Shalom; Martinez Val, Josè Maria; Hora, Heinrich

2016-05-15

Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 10{sup 9} alphas. We suggest that these unexpected very high fusion reactions of proton with {sup 11}B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-{sup 11}B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

Structural and biological characterization of a capsular polysaccharide produced by Staphylococcus haemolyticus.

PubMed

Flahaut, Sigrid; Vinogradov, Evgeny; Kelley, Kathryn A; Brennan, Shannon; Hiramatsu, Keiichi; Lee, Jean C

2008-03-01

The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFG(Sh)) showed > or = 57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLM(Sh) genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: -3-alpha-L-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-beta-D-Glc)-4-alpha-D-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent.

Absolute configuration of a chiral CHD group via neutron diffraction: confirmation of the absolute stereochemistry of the enzymatic formation of malic acid

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

Bau, R.; Brewer, I.; Chiang, M.Y.

Neutron diffraction has been used to monitor the absolute stereochemistry of an enzymatic reaction. (-)(2S)malic-3-d acid was prepared by the action of fumarase on fumaric acid in D/sub 2/O. After a large number of cations were screened, it was found that (+)(R)..cap alpha..-phenylethylamine forms the large crystals necessary for a neutron diffraction analysis. The subsequent structure determination showed that (+)(R)..cap alpha..-phenylethylammonium (-)(2S)malate-3-d has an absolute configuration of R at the CHD site. This result confirms the absolute stereochemistry of fumarate-to-malate transformation as catalyzed by the enzyme fumarase.

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

Lopes, E.S.N.; Cremasco, A.; Afonso, C.R.M.

Aging heat treatment can be a good way to optimize mechanical properties, changing the microstructure, and hence, the mechanical behavior of Ti alloys. The effects of aging heat treatments on {beta}-type Ti-30Nb alloy were investigated to evaluate the kinetics of {alpha}'' {yields} {alpha} + {beta} transformation. The results obtained from differential scanning calorimetry and high-temperature X-ray diffraction experiments indicated the complete decomposition of orthorhombic {alpha}'' phase at close to 300 deg. C, followed by {alpha} phase precipitation at 470 deg. C. The aging heat treatments also enabled us to observe a transformation sequence {alpha}'' {yields} {beta} + {omega} {yields} {beta}more » + {omega} + {alpha}, indicating martensite decomposition and {omega} phase precipitation at 260 deg. C after 2 h, followed by {alpha} phase nucleation after heating at 400 deg. C for 1 h. The elastic modulus and Vickers hardness of Ti-30Nb alloy were found to be very sensitive to the microstructural changes caused by heat treatment. - Highlights: {yields} DSC and XRD shed light on the {alpha}'' decomposition and nucleation of {omega} and {alpha} phases. {yields} Aging allows for {alpha}''{yields}{beta} transformation and nucleation of {omega} dispersed in the {beta} matrix. {yields} During aging, {alpha}'' interplanar distances are reduced to enable {beta} phase nucleation. {yields} Mechanical behavior is dependent on the microstructure and the phases in the alloy. {yields} It is not possible to obtain high strength and low elastic modulus by applying aging.« less

Role of carotenoids in the phototropic response of corn seedings

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

Vierstra, R.D.; Poff, K.L.

1981-10-01

The herbicide 4 chloro-5-(methylamino)-2-..cap alpha..,..cap alpha..,..cap alpha..,-trifluoro-m-tolyl)-3(2H)- pyridazinone (SAN 9789), which blocks the synthesis in higher plants of colored carotenoids but not of flavins, was used to examine the involvement of carotenoids in corn seeding phototropism. It was concluded that ''bulk'' carotenoids are not the photoreceptor pigment based on the results that increasing concentrations of SAN 9789 (up to 100 micromolar) did not alter the phototropic sensitivity to 380 nanometers light (using geotropism as a control) and did not increase the threshold intensities of fluence response curves for both 380 and 450 nanometers light even though carotenoid content was reducedmore » to 1 to 2% of normal. SAN 9789 treatment, however, did reduce seedling sensitivity toward 450 nanometers light indicating that carotenoids are involved in phototropism. Carotenoids, which are located mainly in the primary leaves, may act in phototropism as an internal screen, enhancing the light intensity gradient across the seedling and thus contributing to the ability of the seedling to perceive light direction. These results, indicate that the action spectra for phototropic responses can be significantly affected by the absorbance of screening pigments in vivo thus altering its shape from the in vitro absorption spectrum of the photoreceptor pigment.« less

Secondary. cap alpha. -deuterium kinetic isotope effects in solvolyses of ferrocenylmethyl acetate and benzoate in ethanol

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

Sutic, D.; Asperger, S.; Borcic, S.

1982-12-17

Secondary ..cap alpha..-deuterium kinetic isotope effects (KIE) in solvolyses of ferrocenyldideuteriomethyl acetate and benzoate were determined in 96% (v/v) ethanol, at 25/sup 0/C, as k/sub H//k/sub D/ = 1.24 and 1.26, respectively. The KIEs were also determined in the presence of 0.1 mol dm/sup -3/ lithium perchlorate: the k/sub H//k/ sub D/ values were 1.23 and 1.22 for acetate and benzoate complexes, respectively. The maximum KIE for the C-O bond cleavage of a primary substrate is as large as, or larger than, that of secondary derivatives, which is estimated to be 1.23 per deuterium. The measured KIE of about 12%more » per D therefore represents a strongly reduced effect relative to its maximum. The solvolyses exhibit ''a special salt effect''. This effect indicates the presence of solvent-separated ion pairs and the return to tight pairs. As the maximum KIE is expected in solvolyses involving transformation of one type of ion pair into another, the strongly reduced ..cap alpha..-D KIE supports the structure involving direct participation of electrons that in the ground state are localized at the iron atom. The alkyl-oxygen cleavage is accompanied by 10-15% acyl-oxygen cleavage.« less

Hydrogen transport and hydrogen embrittlement in stainless steels

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

Perng, T.P.

1985-01-01

In order to understand the kinetics of gaseous hydrogen-induced slow crack growth (SCG) in metastable austenitic stainless steels, hydrogen permeation and/or cracking velocity were measured and compared for three types of stainless steels. These included austenitic, ferritic, and duplex (..gamma../..cap alpha..) alloys. Deformation in AISI 301 resulted in various amounts of ..cap alpha..' martensite, which enhanced the effective hydrogen diffusivity and permeability. No phase transformation was observed in deformed AISI 310. The effective hydrogen diffusivity in this alloy was slightly reduced after plastic deformation, presumably by dislocation trapping. In either the dynamic or static tensile test, AISI 301 exhibited themore » greatest hydrogen embrittlement and therefore the highest SCG velocity among all the alloys tested in this work. The SCG velocity was believed to be controlled by the rate of accumulation of hydrogen in the embrittlement region ahead of the crack tip and therefore could be explained with the hydrogen transport parameters measured from the permeation experiments. The relatively high SCG velocity in AISI 301 was probably due to the fast transport of hydrogen through the primarily stress-induced ..cap alpha..' phase around the crack. No SCG was observed in AISI 310. The presence of H/sub 2/O vapor was found to reduce both the hydrogen permeation and SCG velocity.« less

Vacuum energy density near static distorted black holes

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

Frolov, V.P.; Sanchez, N.

1986-03-15

We investigate the contribution of massless fields of spins 0, 1/2, and 1 to the vacuum polarization near the event horizon of static Ricci-flat space-times. We do not assume any particular spatial symmetry. Within the Page-Brown ''ansatz'' we calculate /sup ren/ and /sup ren/ near static distorted black holes, for both the Hartle-Hawking (Vertical Bar>/sub H/) and Boulware (Vertical Bar>/sub B/) vacua. Using Israel's description of static space-times, we express these quantities in an invariant geometric way. We obtain that /sub H//sup ren/ and /sub H//sup ren/ near the horizon depend only on the two-dimensional geometry of the horizon surface.more » We find /sub H//sup ren/ = (1/48..pi../sup 2/ )K/sub 0/, /sub H//sup ren/ = (7..cap alpha..+12..beta.. )K/sub 0/ /sup 2/-..cap alpha../sup(/sup 2/)..delta..K/sub 0/. $K sub 0: is the Gaussian curvature of the horizon, and ..cap alpha.. and ..beta.. are numerical coefficients depending on the spin of a field. The term in /sup(/sup 2/)..delta..K/sub 0/ is characteristic of the distortion of the black hole. When the event horizon is not distorted, K/sub 0/ is a constant and this term disappears.« less

Implications of the dependence of the elastic properties of DNA on nucleotide sequence.

PubMed

Olson, Wilma K; Swigon, David; Coleman, Bernard D

2004-07-15

Recent advances in structural biochemistry have provided evidence that not only the geometric properties but also the elastic moduli of duplex DNA are strongly dependent on nucleotide sequence in a way that is not accounted for by classical rod models of the Kirchhoff type. A theory of sequence-dependent DNA elasticity is employed here to calculate the dependence of the equilibrium configurations of circular DNA on the binding of ligands that can induce changes in intrinsic twist at a single base-pair step. Calculations are presented of the influence on configurations of the assumed values and distribution along the DNA of intrinsic roll and twist and a modulus coupling roll to twist. Among the results obtained are the following. For minicircles formed from intrinsically straight DNA, the distribution of roll-twist coupling strongly affects the dependence of the total elastic energy Psi on the amount alpha of imposed untwisting, and that dependence can be far from quadratic. (In fact, for a periodic distribution of roll-twist coupling with a period equal to the intrinsic helical repeat length, Psi can be essentially independent of alpha for -90 degrees < alpha <90 degrees.) When the minicircle is homogeneous and without roll-twist coupling, but with uniform positive intrinsic roll, the point at which Psi attains its minimum value shifts towards negative values of alpha. It is remarked that there are cases in which one can relate graphs of Psi versus alpha to the 'effective values' of bending and twisting moduli and helical repeat length obtained from measurements of equilibrium distributions of topoisomers and probabilities of ring closure. For a minicircle formed from DNA that has an 'S' shape when stress-free, the graphs of Psi versus alpha have maxima at alpha = 0. As the binding of a twisting agent to such a minicircle results in a net decrease in Psi, the affinity of the twisting agent for binding to the minicircle is greater than its affinity for binding to unconstrained DNA with the same sequence.

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

Calva-Tellez, E.; Yennie, D.R.

The Coulomb corrections of relative order Z..cap alpha.. to inelastic electron and muon scattering are examined. Although individual terms are large, the net result is too small to be experimentally significant.

Two-cluster structure of some alpha-scattering resonances in the sd shell

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

Budzanowski, A.; Grotowski, K.; Strzalkowski, A.

1975-01-01

The excitation functions of the elastic scattering of alpha particles at backward angles on $sup 24$Mg and $sup 28$Si nuclei in the energy range from 23 to 28 MeV measured by Bobrowska et al. exhibit distinct maxima. It was shown that these maxima are not correlated with the structures seen in the excitation functions of the ($alpha$,$alpha$') and ($alpha$,p) reactions leading to low- lying excited states of the final nucleus possibly indicating the presence of Ericson fluctuations. (auth)

Overexpression of TGF-alpha increases lung tissue hysteresivity in transgenic mice.

PubMed

Pillow, J J; Korfhagen, T R; Ikegami, M; Sly, P D

2001-12-01

Increased transforming growth factor (TGF)-alpha has been observed in neonatal chronic lung disease. Lungs of transgenic mice that overexpress TGF-alpha develop enlarged air spaces and pulmonary fibrosis compared with wild-type mice. We hypothesized that these pathological changes may alter the mechanical coupling of viscous and elastic forces within lung parenchyma. Respiratory impedance was measured in open-chested, tracheostomized adult wild-type and TGF-alpha mice by using the forced oscillation technique (0.25-19.63 Hz) delivered by flexiVent (Scireq, Montreal, PQ). Estimates of airway resistance (Raw), inertance (I), and the coefficients of tissue damping (G(L)) and tissue elastance (H(L)) were obtained by fitting a model to each impedance spectrum. Hysteresivity (eta) was calculated as G(L)/H(L). There was a significant increase in eta (P < 0.01) and a trend to a decrease in H(L) (P = 0.07) of TGF-alpha mice compared with the wild-type group. There was no significant change in Raw, I, or G(L). Structural abnormality present in the lungs of adult TGF-alpha mice alters viscoelastic coupling of the tissues, as evidenced by a change in eta.

Neutrophil-derived alpha defensins control inflammation by inhibiting macrophage mRNA translation

PubMed Central

Tomlinson, Gareth H.; Miles, Katherine; Smith, Richard W. P.; Rossi, Adriano G.; Hiemstra, Pieter S.; van ’t Wout, Emily F. A.; Dean, Jonathan L. E.; Gray, Nicola K.; Lu, Wuyuan; Gray, Mohini

2016-01-01

Neutrophils are the first and most numerous cells to arrive at the site of an inflammatory insult and are among the first to die. We previously reported that alpha defensins, released from apoptotic human neutrophils, augmented the antimicrobial capacity of macrophages while also inhibiting the biosynthesis of proinflammatory cytokines. In vivo, alpha defensin administration protected mice from inflammation, induced by thioglychollate-induced peritonitis or following infection with Salmonella enterica serovar Typhimurium. We have now dissected the antiinflammatory mechanism of action of the most abundant neutrophil alpha defensin, Human Neutrophil Peptide 1 (HNP1). Herein we show that HNP1 enters macrophages and inhibits protein translation without inducing the unfolded-protein response or affecting mRNA stability. In a cell-free in vitro translation system, HNP1 powerfully inhibited both cap-dependent and cap-independent mRNA translation while maintaining mRNA polysomal association. This is, to our knowledge, the first demonstration of a peptide released from one cell type (neutrophils) directly regulating mRNA translation in another (macrophages). By preventing protein translation, HNP1 functions as a “molecular brake” on macrophage-driven inflammation, ensuring both pathogen clearance and the resolution of inflammation with minimal bystander tissue damage. PMID:27044108

Assessment of posttraumatic stress disorder in Cambodian refugees using the Clinician-Administered PTSD Scale: psychometric properties and symptom severity.

PubMed

Hinton, Devon E; Chhean, Dara; Pich, Vuth; Pollack, M H; Orr, Scott P; Pitman, Roger K

2006-06-01

Posttraumatic stress disorder (PTSD) symptoms were assessed by using the Clinician-Administered PTSD Scale (CAPS) in a consecutive sample of Cambodian refugees attending a psychiatric clinic in the United States. Psychometric properties of the translated CAPS and severity of PTSD-related symptoms were examined. The CAPS demonstrated adequate psychometric properties, including coefficient alpha (.92) and item-total correlations (.48-.85). Of the sample 56% (101/179) met Diagnostic and Statistical Manual of Mental Disorders, fourth edition, criteria for current PTSD. Those patients who met criteria for current PTSD had significantly higher CAPS total scores (M = 65.3, SD = 18.1) than those who did not meet the criteria (M = 13.9, SD = 16.7).

Effects of preventing O-glycosylation on the secretion of human chorionic gonadotropin in Chinese hamster ovary cells

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

Matzuk, M.M.; Krieger, M.; Corless, C.L.

1987-09-01

Human chorionic gonadotropin (hCG) is a member of a family of heterodimeric glycoprotein hormones that have a common ..cap alpha.. subunit but differ in their hormone-specific ..beta..-subunits. The ..beta.. subunit of hCG (hCG..beta..) is unique among the ..beta.. subunits in that it contains four mucin-like O-linked oligosaccharides attached to a carboxyl-terminal extension. To study the effects of O-glycosylation on the secretion and assembly of hCG, expression vectors containing either hCG..beta.. gene alone or together with the hCG..cap alpha.. gene were transfected into a mutant Chinese hamster ovary cell line, 1d1D, which exhibits a reversible defect in O-glycosylation. The results revealmore » that hCG..beta.. can be secreted normally in the absence of its O-linked oligosaccharides. hCG..beta.. devoid of O-linked carbohydrate can also combine efficiently with hCG..cap alpha.. and be secreted as an intact dimer. The authors conclude that in Chinese hamster ovary cells, the hCG..beta.. O-linked chains play no role in the assembly and secretion of hCG. The normal and O-linked oligosaccharide-deficient forms of hCG secreted by these cells should prove useful in examining the role of O-linked chains on the biological function of hCG.« less

Hormonal regulation of hepatic glycogenolysis in the carp, Cyprinus carpio

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

Janssens, P.A.; Lowrey, P.

1987-04-01

Carp (Cyprinus carpio) liver maintained normal glycogen content and enzyme complement for several days in organ culture. Epinephrine-stimulated glycogenolysis, phosphorylase activation, and cyclic AMP (cAMP) accumulation in a concentration-dependent manner with EC/sub 50/s of 100, 100, and 500 nM, respectively. These actions were blocked by the ..beta..-adrenergic antagonist, propranolol, but not by the ..cap alpha..-adrenergic antagonist phentolamine. Glycogenolysis and tissue cAMP were uninfluenced by 10/sup -6/ M arginine vasotocin, arginine vasopressin, lysine vasotocin, lysine vasopressin, mesotocin, or oxytocin, but were slightly increased by 10/sup -5/ M isotocin and slightly decreased by 10/sup -6/ M angiotensin II. (/sup 125/I)-iodocyanopindolol (ICP), amore » ..beta..-adrenergic ligand, bound to isolated carp liver membranes with a K/sub D/ of 83 pM. Maximum binding of 45 fmol/mg protein was at 600 pM. Propranolol, isoprenaline, epinephrine, phenylephrine, norepinephrine, and phenoxybenzamine displaced ICP with K/sub D/s of 100 nM, 2, 20, 20, 60, and 200 ..mu..M, respectively. The ..cap alpha..-adrenergic antagonists, yohimbine and prazosin, showed no specific binding. These data provide evidence that catecholamines act via ..beta..-adrenergic receptors in carp liver and that ..cap alpha..-adrenergic receptors are not present. Vasoactive peptides play no significant role in regulation of carp liver glycogenolysis.« less

Hydrogen and deuterium in the local interstellar medium

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

Murthy, J.N.

1987-01-01

This work reports on the results of a series of IUE observations of interstellar HI and DI Ly..cap alpha.. absorption against the chromospheric Ly..cap alpha.. emission of the nearby late-type stars ..cap alpha.. Cen B(1.3 pc), epsilon Eri (3.3 pc), Procyon (3.5 pc), Altair (5.1 pc), Capella (13.2 pc), and HR 1099 (33 pc). The density, velocity dispersion, and bulk velocity of the neutral hydrogen along the line of sight to each of these stars was derived. Lower limits were placed on the deuterium-to-hydrogen (D/H) ratio towards the same stars. These IUE results are generally consistent with previous observations ofmore » the same stars with the Copernicus satellite showing that this modeling procedure is independent of stellar variations over a period of several years. The HI absorption profile towards Altair shows a broad saturated core and steep line wings, consistent with a multicomponent interstellar medium in that direction. The bulk velocities towards the other stars are consistent with a bulk flow from the approximate direction of the galactic center but do show local variations from a uniform flow, possibly indicating a complicated velocity structure even in the solar neighborhood. Interstellar deuterium is detected towards every star except Altair and the derived values for the D/H ratio are consistent with those previously found with Copernicus.« less

Asparagine-linked oligosaccharides on lutropin, follitropin, and thyrotropin: distributions of sulfated and sialylated oligosaccharides on bovine, ovine, and human pituitary glycoprotein hormones

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

Green, E.D.; Baenziger, J.U.

1988-01-05

The asparagine-linked oligosaccharides on the pituitary glycoprotein hormones lutropin (LH), follitropin (FSH), and thyrotropin (TSH) consist of a heterogeneous array of neutral, sulfated, sialylated, and sulfated/sialylated structures. In this study, the authors determined the relative quantities of the various asparagine-linked oligosaccharides on LH, FSH, and TSH from these three animal species. The proportions of sulfated versus sialylated oligosaccharides varied markedly among the different hormones. Both hormone- and animal species-specific differences in the types and distributions of sulfated, sialylated, and sulfated/sialylated structures were evident. In particular, LH and FSH, which are synthesized in the same pituitary cell and bear ..cap alpha..-subunitsmore » with the identical amino acid sequence, contained significantly different distributions of sulfated and sialylated oligosaccharides. For all three animal species, the ratio of sialylated to sulfated oligosaccharides differed by >10-fold for LH and FSH, with sulfated structures dominating on LH and sialylated structures on FSH. Sialylated oligosaccharides were also heterogeneous with respect to sialic acid linkage (..cap alpha..2,3 versus ..cap alpha..2,6). The differences in oligosaccharide structures among the various pituitary glycoprotein hormones as well as among the various glycosylation sites within a single hormone support the hypothesis that glycosylation may serve important functional roles in the expression and/or regulation of hormone bioactivity.« less

Effects of dietary saw palmetto on the prostate of transgenic adenocarcinoma of the mouse prostate model (TRAMP).

PubMed

Wadsworth, Teri L; Worstell, Teresa R; Greenberg, Norman M; Roselli, Charles E

2007-05-01

Several of the proposed mechanisms for the actions of the liposterolic extract of saw palmetto (SPE) are exerted on known risk factors for prostate cancer (CaP). This study investigated whether SPE could prevent the progression of CaP in a transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Two different doses of SPE designed to deliver 50 mg/kg/day SPE and 300 mg/kg/day SPE were administered in a custom diet to TRAMP mice for 12 or 24 weeks. Body and organ weights were used to evaluate toxicity, and radioimmunoassay was used to measure plasma and tissue androgen levels to monitor effects of SPE on 5alpha reductase activity. Prostate tissues were evaluated histologically to determine the effect of treatment on tumor grade, cell proliferation, and apoptosis. Treatment with 300 mg/kg/day SPE from 4 to 24 weeks of age significantly reduced the concentration of 5alpha-dihydrotestosterone (DHT) in the prostate and resulted in a significant increase in apoptosis and significant decrease in pathological tumor grade and frank tumor incidence. Dietary supplementation with SPE may be effective in controlling CaP tumorigenesis. SPE suppression of prostatic DHT levels lends support to the hypothesis that inhibition of the enzyme 5alpha-reductase is a mechanism of action of this substance. (c) 2007 Wiley-Liss, Inc.

Construction of Reference Data for Tissue Characterization of Arterial Wall Based on Elasticity Images

NASA Astrophysics Data System (ADS)

Inagaki, Jun; Hasegawa, Hideyuki; Kanai, Hiroshi; Ichiki, Masataka; Tezuka, Fumiaki

2005-06-01

Previously, we developed the phased tracking method [H. Kanai et al.: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43 (1996) 791] for measuring the minute change in thickness during one heartbeat and the elasticity of the arterial wall. By comparing pathological images with elasticity images measured with ultrasound, elasticity distributions for respective tissues in the arterial wall were determined. We have already measured the elasticity distributions for lipids and fibrous tissues (mixtures of smooth-muscle and collagen fiber) [H. Kanai et al.: Circulation 107 (2003) 3018]. In this study, elasticity distributions were measured for blood clots and calcified tissues. We discuss whether these elasticity distributions, which were measuerd in vitro, can be used as reference data for classifying cross-sectional elasticity images measured in vivo into respective tissues. In addition to the measurement of elasticity distributions, correlations between collagen content and elasticity were investigated with respect to fibrous tissue to estimate the collagen and smooth-muscle content based on elasticity. Collagen and smooth-muscle content may be important factors in determining the stability of the fibrous cap of atherosclerotic plaque. Therefore, correlations between elasticity and elements of the tissue in the arterial wall may provide useful information for the noninvasive diagnosis of plaque vulnerability.

Expanded turn conformations: characterization and sequence-structure correspondence in alpha-turns with implications in helix folding.

PubMed

Dasgupta, Bhaskar; Pal, Lipika; Basu, Gautam; Chakrabarti, Pinak

2004-05-01

Like the beta-turns, which are characterized by a limiting distance between residues two positions apart (i, i+3), a distance criterion (involving residues at positions i and i+4) is used here to identify alpha-turns from a database of known protein structures. At least 15 classes of alpha-turns have been enumerated based on the location in the phi,psi space of the three central residues (i+1 to i+3)-one of the major being the class AAA, where the residues occupy the conventional helical backbone torsion angles. However, moving towards the C-terminal end of the turn, there is a shift in the phi,psi angles towards more negative phi, such that the electrostatic repulsion between two consecutive carbonyl oxygen atoms is reduced. Except for the last position (i+4), there is not much similarity in residue composition at different positions of hydrogen and non-hydrogen bonded AAA turns. The presence or absence of Pro at i+1 position of alpha- and beta-turns has a bearing on whether the turn is hydrogen-bonded or without a hydrogen bond. In the tertiary structure, alpha-turns are more likely to be found in beta-hairpin loops. The residue composition at the beginning of the hydrogen bonded AAA alpha-turn has similarity with type I beta-turn and N-terminal positions of helices, but the last position matches with the C-terminal capping position of helices, suggesting that the existence of a "helix cap signal" at i+4 position prevents alpha-turns from growing into helices. Our results also provide new insights into alpha-helix nucleation and folding. Copyright 2004 Wiley-Liss, Inc.

Modeling of aerodynamic heat flux and thermoelastic behavior of nose caps of hypersonic vehicles

NASA Astrophysics Data System (ADS)

Persova, Marina G.; Soloveichik, Yury G.; Belov, Vasiliy K.; Kiselev, Dmitry S.; Vagin, Denis V.; Domnikov, Petr A.; Patrushev, Ilya I.; Kurskiy, Denis N.

2017-07-01

In this paper, the problem of numerical modeling of thermoelastic behavior of nose caps of hypersonic vehicles at different angles of attack is considered. 3D finite element modeling is performed by solving the coupled heat and elastic problems taking into account thermal and mechanical properties variations with temperature. A special method for calculating the aerodynamic heat flux entering the nose cap from its surface is proposed. This method is characterized by very low computational costs and allows calculating the aerodynamic heat flux at different values of the Mach number and angles of attack which may vary during the aerodynamic heating. The numerical results obtained by the proposed approach are compared with the numerical results and experimental data obtained by other authors. The developed approach has been used for studying the impact of the angle of attack on the thermoelastic behavior of nose caps main components.

A capacitive, biocompatible and adhesive electrode for long-term and cap-free monitoring of EEG signals.

PubMed

Lee, Seung Min; Kim, Jeong Hun; Byeon, Hang Jin; Choi, Yoon Young; Park, Kwang Suk; Lee, Sang-Hoon

2013-06-01

Long-term electroencephalogram (EEG) monitoring broadens EEG applications to various areas, but it requires cap-free recording of EEG signals. Our objective here is to develop a capacitive, small-sized, adhesive and biocompatible electrode for the cap-free and long-term EEG monitoring. We have developed an electrode made of polydimethylsiloxane (PDMS) and adhesive PDMS for EEG monitoring. This electrode can be attached to a hairy scalp and be completely hidden by the hair. We tested its electrical and mechanical (adhesive) properties by measuring voltage gain to frequency and adhesive force using 30 repeat cycles of the attachment and detachment test. Electrode performance on EEG was evaluated by alpha rhythm detection and measuring steady state visually evoked potential and N100 auditory evoked potential. We observed the successful recording of alpha rhythm and evoked signals to diverse stimuli with high signal quality. The biocompatibility of the electrode was verified and a survey found that the electrode was comfortable and convenient to wear. These results indicate that the proposed EEG electrode is suitable and convenient for long term EEG monitoring.

Cryopyrin-associated periodic syndromes: development of a patient-reported outcomes instrument to assess the pattern and severity of clinical disease activity.

PubMed

Hoffman, Hal M; Wolfe, Frederick; Belomestnov, Pavel; Mellis, Scott J

2008-09-01

Development of an instrument for characterization of symptom patterns and severity in patients with cryopyrin-associated periodic syndromes (CAPS). Two generations of daily health assessment forms (DHAFs) were evaluated in this study. The first-generation DHAF queried 11 symptoms. Analyses of results obtained with that instrument identified five symptoms included in a revised second-generation DHAF that was tested for internal consistency and test-retest reliability. This DHAF was also assessed during the initial portion of a phase 3 clinical study of CAPS treatment. Forty-eight CAPS patients provided data for the first-generation DHAFs. Five symptoms (rash, fever, joint pain, eye redness/pain, and fatigue) were included in the revised second-generation DHAF. Symptom severity was highly variable during all study phases with as many as 89% of patients reporting at least one symptom flare, and percentages of days with flares reaching 58% during evaluation of the second-generation instrument. Mean composite key symptom scores (KSSs) computed during evaluation of the second-generation DHAF correlated well with Physician's Global Assessment of Disease Activity (r=0.91, p<0.0001) and patient reports of limitations of daily activities (r=0.68, p<0.0001). Test-retest reliability and Cronbach's alpha's were high (0.93 and 0.94, respectively) for the second-generation DHAF. Further evaluation of this DHAF during a baseline period and placebo treatment in a phase 3 clinical study of CAPS patients indicated strong correlations between baseline KSS and Physician's Global Assessment of Disease Activity. Cronbach's alpha's at baseline and test-retest reliability were also high. Potentially important study limitations include small sample size, the lack of a standard tool for CAPS symptom assessment against which to validate the DHAF, and no assessment of the instrument's responsivity to CAPS therapy. The DHAF is a new instrument that may be useful for capturing symptom patterns and severity in CAPS patients and monitoring responses to therapies for these conditions.

Preparation of alpha-cyclodextrin-terminated polyrotaxane consisting of beta-cyclodextrins and pluronic as a building block of a biodegradable network.

PubMed

Ooya, Tooru; Ito, Akihiro; Yui, Nobuhiko

2005-05-23

A beta-CD-based biodegradable polyrotaxane was prepared by capping both terminals of polypseudorotaxane consisting of hydrazide-terminated PEG-block-PPG-block-PEG (Pluronic P-105) and beta-CD-succinates with mono-aldehyde alpha-CDs. By decreasing pH, the fluorescent intensity of TNS was increased with time, indicating cleavage of the terminal hydrazone bonds followed by beta-CD-succinate release. The terminal alpha-CD moieties of the polyrotaxane are useful for self-assembled formation with some guest molecules. [Diagram: see text

Earth's surface loading study using InSAR

NASA Astrophysics Data System (ADS)

Amelung, F.; Zhao, W.; Doin, M. P.

2014-12-01

Earth's surface loading/unloading such as glacier retreat, lake water level change, ocean tide, cause measurable (centimeter to millimeter) surface deformation from Synthetic Aperture Radar Interferometry (InSAR). Such seasonal or decadal deformation signals are useful for the estimation of the amount of load and the parameterization of crust and upper mantle - typically under an elastic or a visco-elastic mechanism. Since 2010, we established a study of surface loading using small baseline InSAR time-series analysis. Four sites are included in this study, which are Vatnajokull ice cap, Lake Yamzho Yumco, Petermann glacier, and Barnes ice cap using different satellites such as ERS1/2, Envisat, Radarsat-2, TerraSAR-X. We present results that mainly answer three questions: 1) Is InSAR time-series capable for the detection of millimeter level deformation due to surface loading; 2) When the Earth's rheology is known, how much load change occured; 3) When the surface loading is known, what are the Earth's parameters such as Young's modulus, viscosity. For glacier retreat problem, we introduce a new model for the ice mass loss estimation considering the spatial distribution of ice loss. For lake unloading problem, modeled elastic parameters are useful for the comparison to other 1-D models, e.g. the model based on seismic data.

Short-term variations of Icelandic ice cap mass inferred from cGPS coordinate time series

NASA Astrophysics Data System (ADS)

Compton, Kathleen; Bennett, Richard A.; Hreinsdóttir, Sigrún; van Dam, Tonie; Bordoni, Andrea; Barletta, Valentina; Spada, Giorgio

2017-06-01

As the global climate changes, understanding short-term variations in water storage is increasingly important. Continuously operating Global Positioning System (cGPS) stations in Iceland record annual periodic motion—the elastic response to winter accumulation and spring melt seasons—with peak-to-peak vertical amplitudes over 20 mm for those sites in the Central Highlands. Here for the first time for Iceland, we demonstrate the utility of these cGPS-measured displacements for estimating seasonal and shorter-term ice cap mass changes. We calculate unit responses to each of the five largest ice caps in central Iceland at each of the 62 cGPS locations using an elastic half-space model and estimate ice mass variations from the cGPS time series using a simple least squares inversion scheme. We utilize all three components of motion, taking advantage of the seasonal motion recorded in the horizontal. We remove secular velocities and accelerations and explore the impact that seasonal motions due to atmospheric, hydrologic, and nontidal ocean loading have on our inversion results. Our results match available summer and winter mass balance measurements well, and we reproduce the seasonal stake-based observations of loading and melting within the 1σ confidence bounds of the inversion. We identify nonperiodic ice mass changes associated with interannual variability in precipitation and other processes such as increased melting due to reduced ice surface albedo or decreased melting due to ice cap insulation in response to tephra deposition following volcanic eruptions, processes that are not resolved with once or twice-yearly stake measurements.

Solubilization of cyclohexane in aqueous solutions of sodium. cap alpha. -alkyl alkanoates

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

Sagitani, H.; Suzuki, T.; Nagai, M.

1982-01-01

The effect of branched alkyl chain length and the position of the COONa group on the solubilizing power of n-alkane sodium carboxylates was studied. The lipophilic property and the amount of solubilized cyclohexane increased with the branched chain length of branched soaps, and with the change of the position of the -COONa group from 3 to 7 in the alkyl chain of pentadecane -3, -5, and -7 sodium carboxylates. Alpha-branched soaps having proper branched alkyl chains were better solubilizers for cyclohexane than straight chain compounds. The amount of cyclohexane solublized by C/sub 10/ H/sub 21/ CH(C/sub 6/H/sub 13/) COONa wasmore » about three times greater than the amount solubilized by C/sub 17/ H/sub 35/ COONa. There was a marked increase in the solubilization of cyclohexane replacing ..cap alpha..-branched fatty acid soaps with optimum amount of cosurfactants such as C/sub 8/H/sub 17/ (OCH/sub 2/CH/sub 2/)/sub 2/OH. Namely, solubilization increased markedly at the optimum hydrophile-lipophile balance of mixed surfactant. 21 references.« less

Inhibition of radioemesis by disruption of catecholamines in dogs

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

Luthra, Y.K.; Mattsson, J.L.; Yochmowitz, M.G.

1981-03-01

Dogs were treated 30 min to 1 h before x irradiation with ..cap alpha..-methyl-p-tyrosine or 6-hydroxydopamine. A third group of dogs was given a known antiradioemetic drug, haloperidol to verify the sensitivity of the procedure. Irradiated but untreated controls were also used. Light methoxyflurane anesthesia was used for restraint during the exposure. Exposure dose was 800 rad kerma delivered at 50 rad/min to a 10 x 10-cm area covering the abdominal area from xiphoid to pubis. Haloperidol and 6-hydroxydopamine significantly reduced the number of emetic episodes and delayed the onset time to the first episode, ..cap alpha..-Methyl-p-tyrosine caused no significantmore » changes. The effectiveness of 6-hydroxydopamine indicates that catecholaminergic neurons are involved in radioemesis, whereas haloperidol and phenothiazine-derivative tranquilizers inhibit radiomesis by blocking catecholamine receptor neurons.« less

ADP-ribosylation of membrane components by pertussis and cholera toxin

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

Ribeiro-Neto, F.A.P.; Mattera, F.; Hildebrandt, J.D.

1985-01-01

Pertussis and cholera toxins are important tools to investigate functional and structural aspects of the stimulatory (N/sub s/) and inhibitory (N/sub i/) regulatory components of adenylyl cyclase. Cholera toxin acts on N/sub s/ by ADP-ribosylating its ..cap alpha../sub s/ subunit; pertussis toxin acts on N/sub i/ by ADP-ribosylating its ..cap alpha..; subunit. By using (/sup 32/P)NAD/sup +/ and determining the transfer of its (/sup 32/P)ADP-ribose moiety to membrane components, it is possible to obtain information on N/sub s/ and N/sub i/. A set of protocols is presented that can be used to study simultaneously and comparatively the susceptibility of N/submore » s/ and N/sub i/ to be ADP-ribosylated by cholera and pertussis toxin.« less

/sup 45/Ca efflux for myometrial cells: comparison of the effects of prostaglandin F/sub 2/. cap alpha. (PGF/sub 2/), oxytocin (OT) and arachidonate (A)

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

Katona, G.; Molnar, M.; Toth, M.

1986-03-01

The aim of this study was to measure PGF/sub 2..cap alpha../-induced Ca/sup 2 +/ release from uterine cells and to compare this to the actions of OT and A. Smooth muscle cells isolated from the uterus (shell gland) of laying hens were cultured for 7 days in M199 plus 10% fetal calf serum. The cells were treated with digitonin (20..mu..M) and preloaded with /sup 45/Ca for 40 min. Addition of PGF/sub 2..cap alpha../ caused a biphasic /sup 45/Ca-efflux. There was a small but significant /sup 45/Ca-release within 30 sec (rapid phase) followed by a larger one within 7 min (slowmore » phase). In comparison, both OT and A stimulated /sup 45/Ca efflux during a single, slow phase. The maximal effect of A was observed at < 7 min, whereas that of OT was slower, peaking after 7 min. Mepacrin, an inhibitor of A release, attenuated the action of OT without having any effect on A promoted /sup 45/Ca-efflux. Indomethacin, an inhibitor of PG synthase, failed to suppress the Ca-releasing effect of A suggesting the A itself or a lipoxygenase product may have been responsible for the observed effects. Moreover, these results provide suggestive evidence that A release is an important step in the action of various uterotonic agents converging on the mobilization of intracellular Ca.« less

Theory of activated glassy dynamics in randomly pinned fluids.

PubMed

Phan, Anh D; Schweizer, Kenneth S

2018-02-07

We generalize the force-level, microscopic, Nonlinear Langevin Equation (NLE) theory and its elastically collective generalization [elastically collective nonlinear Langevin equation (ECNLE) theory] of activated dynamics in bulk spherical particle liquids to address the influence of random particle pinning on structural relaxation. The simplest neutral confinement model is analyzed for hard spheres where there is no change of the equilibrium pair structure upon particle pinning. As the pinned fraction grows, cage scale dynamical constraints are intensified in a manner that increases with density. This results in the mobile particles becoming more transiently localized, with increases of the jump distance, cage scale barrier, and NLE theory mean hopping time; subtle changes of the dynamic shear modulus are predicted. The results are contrasted with recent simulations. Similarities in relaxation behavior are identified in the dynamic precursor regime, including a roughly exponential, or weakly supra-exponential, growth of the alpha time with pinning fraction and a reduction of dynamic fragility. However, the increase of the alpha time with pinning predicted by the local NLE theory is too small and severely so at very high volume fractions. The strong deviations are argued to be due to the longer range collective elasticity aspect of the problem which is expected to be modified by random pinning in a complex manner. A qualitative physical scenario is offered for how the three distinct aspects that quantify the elastic barrier may change with pinning. ECNLE theory calculations of the alpha time are then presented based on the simplest effective-medium-like treatment for how random pinning modifies the elastic barrier. The results appear to be consistent with most, but not all, trends seen in recent simulations. Key open problems are discussed with regard to both theory and simulation.

Theory of activated glassy dynamics in randomly pinned fluids

NASA Astrophysics Data System (ADS)

Phan, Anh D.; Schweizer, Kenneth S.

2018-02-01

We generalize the force-level, microscopic, Nonlinear Langevin Equation (NLE) theory and its elastically collective generalization [elastically collective nonlinear Langevin equation (ECNLE) theory] of activated dynamics in bulk spherical particle liquids to address the influence of random particle pinning on structural relaxation. The simplest neutral confinement model is analyzed for hard spheres where there is no change of the equilibrium pair structure upon particle pinning. As the pinned fraction grows, cage scale dynamical constraints are intensified in a manner that increases with density. This results in the mobile particles becoming more transiently localized, with increases of the jump distance, cage scale barrier, and NLE theory mean hopping time; subtle changes of the dynamic shear modulus are predicted. The results are contrasted with recent simulations. Similarities in relaxation behavior are identified in the dynamic precursor regime, including a roughly exponential, or weakly supra-exponential, growth of the alpha time with pinning fraction and a reduction of dynamic fragility. However, the increase of the alpha time with pinning predicted by the local NLE theory is too small and severely so at very high volume fractions. The strong deviations are argued to be due to the longer range collective elasticity aspect of the problem which is expected to be modified by random pinning in a complex manner. A qualitative physical scenario is offered for how the three distinct aspects that quantify the elastic barrier may change with pinning. ECNLE theory calculations of the alpha time are then presented based on the simplest effective-medium-like treatment for how random pinning modifies the elastic barrier. The results appear to be consistent with most, but not all, trends seen in recent simulations. Key open problems are discussed with regard to both theory and simulation.

Do Reuss and Voigt Bounds Really Bound in High-Pressure Rheology Experiments?

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

Chen,J.; Li, L.; Yu, T.

2006-01-01

Energy dispersive synchrotron x-ray diffraction is carried out to measure differential lattice strains in polycrystalline Fe{sub 2}SiO{sub 4} (fayalite) and MgO samples using a multi-element solid state detector during high-pressure deformation. The theory of elastic modeling with Reuss (iso-stress) and Voigt (iso-strain) bounds is used to evaluate the aggregate stress and weight parameter, {alpha} (0{le}{alpha}{le}1), of the two bounds. Results under the elastic assumption quantitatively demonstrate that a highly stressed sample in high-pressure experiments reasonably approximates to an iso-stress state. However, when the sample is plastically deformed, the Reuss and Voigt bounds are no longer valid ({alpha} becomes beyond 1).more » Instead, if plastic slip systems of the sample are known (e.g. in the case of MgO), the aggregate property can be modeled using a visco-plastic self-consistent theory.« less

Congenital Muscle Disease Study of Patient and Family Reported Medical Information

ClinicalTrials.gov

2017-05-05

Congenital Muscular Dystrophy (Including Unspecified/Undiagnosed); Dystroglycanopathy; Congenital Fiber Type Disproportion; Rigid Spine Muscular Dystrophy; Congenital Myopathy (Including Unspecified/Undiagnosed); Collagen VI CMD (Ullrich CMD, Intermediate, Bethlem Myopathy); Laminin Alpha 2 Related Congenital Muscular Dystrophy; LAMA2-CMD/Merosin Deficient/MDC1A; Walker-Warburg Syndrome; Muscle-Eye-Brain Disease; Fukuyama/Fukutin Related Muscular Dystrophy; Integrin Alpha 7 Deficiency; Integrin Alpha 9 Deficiency; LMNA-CMD/Lamin A/C/Laminopathy; SEPN1-Related Myopathy; Bethlem Myopathy; Actin Aggregation Myopathy; Cap Disease; Central Core Disease; Centronuclear Myopathy; Core Rod Myopathy; Hyaline Body Myopathy; Multiminicore Myopathy; Myotubular Myopathy; Nemaline Myopathy; Tubular Aggregate Myopathy; Zebra Body Myopathy; Reducing Body Myopathy; Spheroid Body Myopathy; LGMD1B (LMNA); LGMD1E (DES); LGMD2G (TCAP); LGMD2H (TRIM32); LGMD2I (FKRP); LGMD2J (TTN); LGMD2K (POMT1); LGMD2M (FKTN); LGMD2N (POMT2); LGMD2O (POMGnT1); LGMD2P (DAG1); LGMD2Q (PLEC1); LGMD2R (DES); LGMD2S (TRAPPC11); LGMD2T (GMPPB); LGMD2U (ISPD); LGMD2V (GAA); Ullrich Congenital Muscular Dystrophy; Titinopathy; Choline Kinase B Receptor; Emery-Dreifuss Muscular Dystrophy; RYR1 Related Myopathy; SYNE1/Nesprin Related Muscular Dystrophy; Telethonin Related Muscular Dystrophy (TCAP/Titin-Cap); Congenital Myasthenic Syndrome; Escobar Syndrome; Myofibrillar Myopathy; Malignant Hyperthermia; Alpha-Dystroglycan Related Muscular Dystrophy (DAG1, DPM1, DPM2, DPM3, FKRP, FKTN); Alpha-Dystroglycan Related Muscular Dystrophy (GAA, ISPD, LARGE, POMT1, POMT2, POMGnT1); Alpha-Dystroglycan Related Muscular Dystrophy (Unspecified/Undiagnosed/Other)

The relationship between red meat allergy and sensitization to gelatin and galactose-alpha-1,3-galactose

PubMed Central

Mullins, Raymond James; James, Hayley; Platts-Mills, Thomas A.E.; Commins, Scott

2012-01-01

Background We have observed patients clinically allergic to red meat and meat-derived gelatin. Objective We describe a prospective evaluation of the clinical significance of gelatin sensitization, the predictive value of a positive test and an examination of the relationship between allergic reactions to red meat and sensitization to gelatin and alpha-Gal. Methods Adult patients evaluated 1997-2011 for suspected allergy/anaphylaxis to medication, insect venom or food were skin tested with gelatin colloid. In vitro (ImmunoCap) testing was undertaken where possible. Results Positive gelatin tests were observed in 40/1335 individuals; 30/40 patients with red meat allergy (12 also clinically allergic to gelatin); 2/2 with gelatin colloid anaphylaxis; 4/172 with idiopathic anaphylaxis (all responded to intravenous gelatin challenge of 0.02 to 0.4g); 4/368 with drug allergy. Testing was negative in all patients with venom allergy (n=241), non-meat food allergy (n=222), and miscellaneous disorders (n=290). ImmunoCap was positive to alpha-Gal in 20/24 meat allergics and in 20/22 with positive gelatin skin tests. The results of gelatin skin testing and anti-alpha-Gal IgE were strongly correlated (r=0.46; P<0.01). Alpha-Gal was detected in bovine gelatin colloids at concentrations of ~ 0.44 to 0.52ug/gm gelatin by inhibition radioimmunoassay. Conclusion Most patients allergic to red meat were sensitized to gelatin and a subset was clinically allergic to both. The detection of alpha-Gal in gelatin and correlation between the results of alpha-Gal and gelatin testing raises the possibility that alpha-Gal IgE may be the target of reactivity to gelatin. The pathogenic relationship between tick bites and sensitization to red meat, alpha-Gal and gelatin (with or without clinical reactivity) remains uncertain. PMID:22480538

Non-Rutherford cross-sections for alpha elastic scattering off Z = 28-38 elements in the energy range up to 10 MeV

NASA Astrophysics Data System (ADS)

Gurbich, A. F.; Bokhovko, M. V.

2018-04-01

The alpha elastic scattering cross-sections for Ni, Cu, and Y were measured at the energies above the onset of the non-Rutherford scattering. The obtained experimental data along with data from literature were incorporated into the theoretical analysis in the framework of the optical model. The optimization of the model parameters provided a basis for the calculations of the differential cross-sections for Z = 28-38 elements in the energy range up to 10 MeV. The obtained cross sections were made available for common use through the SigmaCalc web site at http://sigmacalc.iate.obninsk.ru/.

Crystal structure of Bacillus anthracis transpeptidase enzyme CapD.

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

Wu, R.; Richter, S.; Zhang, R.

2009-09-04

Bacillus anthracis elaborates a poly-{gamma}-d-glutamic acid capsule that protects bacilli from phagocytic killing during infection. The enzyme CapD generates amide bonds with peptidoglycan cross-bridges to anchor capsular material within the cell wall envelope of B. anthracis. The capsular biosynthetic pathway is essential for virulence during anthrax infections and can be targeted for anti-infective inhibition with small molecules. Here, we present the crystal structures of the {gamma}-glutamyltranspeptidase CapD with and without {alpha}-l-Glu-l-Glu dipeptide, a non-hydrolyzable analog of poly-{gamma}-d-glutamic acid, in the active site. Purified CapD displays transpeptidation activity in vitro, and its structure reveals an active site broadly accessible for poly-{gamma}-glutamatemore » binding and processing. Using structural and biochemical information, we derive a mechanistic model for CapD catalysis whereby Pro{sup 427}, Gly{sup 428}, and Gly{sup 429} activate the catalytic residue of the enzyme, Thr{sup 352}, and stabilize an oxyanion hole via main chain amide hydrogen bonds.« less

Strength and Deformation Behaviour of Cap Rocks Above the CO2SINK-Reservoir

NASA Astrophysics Data System (ADS)

Mutschler, T.; Triantafyllidis, T.; Balthasar, K.; Norden, B.

2009-04-01

The cap-rock of the CO2SINK storage site close to Ketzin consists of clay rich rocks which are typical for cap rock formations above CO2 storage reservoirs. The strength and deformation behaviour of such claystone samples are therefore of fundamental importance for the characterization of secure geological storage of CO2. The elastic and anelastic deformation behaviour limits the maximum injection pressure during CO2-injection and is part of the security measures for the long term storage of CO2. The laboratory experiments where performed on samples gathered from the injection well of the Ketzin pilot test site in Germany and are compared with the elastic and anelastic behaviour of samples from the same Keuper formation in a near-surface outcrop in the Southwest of Germany showing a similar lithology. The samples from the outcrop allowed drilling of samples with a standard size of 100 mm diameter and 200 mm height as well as large samples with a diameter of 550 mm and a height of 1200 mm. The investigations have a special emphasis on the viscous behaviour of the clay stones and its scaling behaviour. A special triaxial testing procedure is applied both on standard and large size samples allowing the determination of the strength, stiffness and viscosity behaviour of the rock in one experimental run. Multi-stage technique (stepwise variation of the confining pressure) gives the strength behaviour of each single sample while applying a constant deformation rate. Stepwise varied deformation rates on the other hand lead to steps in the stress-strain-curve from which the viscosity index is determined. The viscosity index is directly used in the Norton's constitutive relations for viscoplastic simulations. The combination of tests allows for the determination of a broad range of elastic and anelastic properties. The comparison of results - both for elastic and anelastic behaviour - from standard and large samples shows that for the examined rocks a scale effect is negligible. Transition from cataclastic to non-cataclastic behaviour - the transition limit - occurs in a similar range of applied levels of pressure and deformation rates even at room temperature. The obtained transition limit is very important for the judgment of the sealing capacity and integrity of the cap rock. The deformation rates predicted for the pressure and temperature conditions of the caprock at Ketzin test site are far beneath the determined transition limit during the injection and after stop of injection. As a 0° friction angle is used for pressure and deformation limit at Ketzin, the measured elastic and anelastic behaviour of the real caprock act as additional safety margin during injection and in the post injection phase. As the examined rocks are typical for many possible storage sites, the discussed results are of importance beyond the Ketzin Pilot Experiment CO2SINK.

Effects of growth retardants and fumigations with ozone and sulfur dioxide on growth and flowering of Euphorbia pulcherrima Willd

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

Cathey, H.M.; Heggestad, H.E.

1973-01-01

Eight cultivars of poinsettia, Euphorbia pulcherrima Willd., were evaluated for sensitivity to ..cap alpha..-cyclopropyl-..cap alpha.. (4-methoxyphenyl)-5-pyrimidine methanol (ancymidol) and protection from ozone and sulfur dioxide injury afforded by applications of ancymidol and (2-chloroethyl) trimethyl ammonium chloride (chlormequat). Foliar sprays of ancymidol were at least 80 to 500 times and the soil drench 1000 times more active than chlormequat in retarding stem elongation. The diam of the bracts was reduced, but branching increased more on plants treated with ancymidol than on untreated plants. The cv. Annette Hegg (AH) was more sensitive to ozone fumigations than was Eckespoint C-1' (C-1). Sulfur dioxidemore » also caused more injury to AH than to C-1. Ancymidol and chlormequat reduced visible injury induced by ozone and sulfur dioxide.« less

Copernicus observational searches for OH and H/sub 2/O in diffuse clouds

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

Smith, W.H.; Snow, T.P. Jr.

1979-03-01

An intensive search for OH and H/sub 2/O in the directions of sigma Sco, ..cap alpha.. Cam, and omicron Per was undertaken with the Copernicus satellite. Multiple scans were carried out over the wavelength region for the expected absorption features due to the OH D--X and H/sub 2/O C--X transitions. The feature due to OH was possibly detected toward sigma Sco, and only an upper limit can be given toward ..cap alpha.. Cam. H/sub 2/O was not detected in any of the stars at the signal level accumulated. The OH abundance toward sigma Sco and the respective lower limits formore » the OH/H/sub 2/O ratios are discussed with regard to the extant models for the steady-state abundances of OH and H/sub 2/O, and shown not to be inconsistent with ion-molecule schemes.« less

Tumor initiating activities of various derivatives of benz(a)anthracene and 7, 12-dimethyl-benz(a)anthracene in mouse skin

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

Slaga, T.J.; Gleason, G.L.; DiGiovanni, J.

Current information indicates that polycyclic aromatic hydrocarbons (PAH) exert their toxic, mutagenic, and carcinogenic activities after they have been metabolically activated by target cells to reactive epoxides. The results obtained from IN VIVO and IN VITRO binding, mutagenicity, metabolism, and carcinogenicity studies have led to the conclusion that BP-7, 8-diol is a proximate carcinogenic metabolite of BP, and the BP-diol-epoxide is an ultimate carcinogenic metabolite of BP. Recent results concerning the strong carcinogenicity of BP-7..beta.., 8..cap alpha..-diol-9..cap alpha..,10..cap alpha..-epoxide in newborn mice and in mouse skin strongly indicate that it is the ultimate carcinogenic metabolite of BP. Since diol-epoxides maymore » be responsible for the carcinogenicity of PAH other than BP, diols and diol-epoxides as well as other derivatives of PAH were tested for skin tumor-initiation in a two-stage system of tumorigenesis. In addition, since activation of methylated PAH may involve the side-chain methyl group, the skin tumor-initiating activity of various side-chain derivatives of methylated PA were determined. In this report, the skin tumor initiation of various derivatives of a nonmethylated PAH, BA as well as a methylated PAH, DMBA are compared. The data suggest that bay region diol-epoxides may be important in BA and DMBA carcinogenicity in mice which is supportive of the theory proposed by Jerina and co-workers which predicts that diol-epoxides in the bay region are the major determinants of PAH carcinogenicity.« less

Assignments of /sup 1/H nuclear magnetic resonances of the cystyl, asparaginyl, and aromatic residues of arginine vasopressin in D/sub 2/O. A comparison with lysine vasopressin and oxytocin in terms of solution conformation

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

Wyssbrod, H.R.; Fischman, A.J.; Live, D.H.

1979-07-18

The resonances of the C/sup ..cap alpha../ and C/sup ..beta../ protons of the cystyl, asparaginyl, and aromatic residues of (8-arginine)vasopressin (AVP) in D/sub 2/O at pD 3.8 and 20/sup 0/C were assigned in a rigorous manner by the use of isotopic isomers of AVP that contain specific replacements of protons by deuterons and by comparison of /sup 1/H NMR characteristics of AVP to those of (8-lysine)vasopressin (LVP) and oxytocin (OT). Although there is extensive overlap of resonances of C/sup ..beta../ protons even at 360 MHz, all of the chemical shifts of these protons and most of the couplings between themmore » and their vicinal C/sup ..cap alpha../ protons could be determined, at least to a first approximation. It was concluded that the cyclic moieties (residues 1-6) of AVP, LVP, and OT possess essentially the same overall backbone conformation, and that the side-chain conformation - or rotamer populations - about the C/sup ..cap alpha../-C/sup ..beta../ bonds of the cystyl residue (positions 1 and 6), the tyrosyl residue (position 2), and the asparaginyl residue (position 5) are similar. This study indicates that selective replacements of C/sup ..beta../ protons by deuterons are necessary to improve the accuracy of coupling constants extracted from 360-MHz spectra of a AVP for use in conformational analysis.« less

Assembly and mechanosensory function of focal adhesions: experiments and models.

PubMed

Bershadsky, Alexander D; Ballestrem, Christoph; Carramusa, Letizia; Zilberman, Yuliya; Gilquin, Benoit; Khochbin, Saadi; Alexandrova, Antonina Y; Verkhovsky, Alexander B; Shemesh, Tom; Kozlov, Michael M

2006-04-01

Initial integrin-mediated cell-matrix adhesions (focal complexes) appear underneath the lamellipodia, in the regions of the "fast" centripetal flow driven by actin polymerization. Once formed, these adhesions convert the flow behind them into a "slow", myosin II-driven mode. Some focal complexes then turn into elongated focal adhesions (FAs) associated with contractile actomyosin bundles (stress fibers). Myosin II inhibition does not suppress formation of focal complexes but blocks their conversion into mature FAs and further FA growth. Application of external pulling force promotes FA growth even under conditions when myosin II activity is blocked. Thus, individual FAs behave as mechanosensors responding to the application of force by directional assembly. We proposed a thermodynamic model for the mechanosensitivity of FAs, taking into account that an elastic molecular aggregate subject to pulling forces tends to grow in the direction of force application by incorporating additional subunits. This simple model can explain a variety of processes typical of FA behavior. Assembly of FAs is triggered by the small G-protein Rho via activation of two major targets, Rho-associated kinase (ROCK) and the formin homology protein, Dia1. ROCK controls creation of myosin II-driven forces, while Dia1 is involved in the response of FAs to these forces. Expression of the active form of Dia1, allows the external force-induced assembly of mature FAs, even in conditions when Rho is inhibited. Conversely, downregulation of Dia1 by siRNA prevents FA maturation even if Rho is activated. Dia1 and other formins cap barbed (fast growing) ends of actin filaments, allowing insertion of the new actin monomers. We suggested a novel mechanism of such "leaky" capping based on an assumption of elasticity of the formin/barbed end complex. Our model predicts that formin-mediated actin polymerization should be greatly enhanced by application of external pulling force. Thus, the formin-actin complex might represent an elementary mechanosensing device responding to force by enhancement of actin assembly. In addition to its role in actin polymerization, Dia1 seems to be involved in formation of links between actin filaments and microtubules affecting microtubule dynamics. Alpha-tubulin deacetylase HDAC6 cooperates with Dia1 in formation of such links. Since microtubules are known to promote FA disassembly, the Dia1-mediated effect on microtubule dynamics may possibly play a role in the negative feedback loop controlling size and turnover of FAs.

Long-term treatment with calcium-alpha-ketoglutarate corrects secondary hyperparathyroidism.

PubMed

Zimmermann, E; Wassmer, S; Steudle, V

1996-01-01

Calcium-alpha-ketoglutarate (Ca-ket) is known as a highly effective phosphate (P) binder in hemodialysis (HD) patients. In addition, alpha-ketoglutarate has been shown to improve metabolic alterations. We investigated the effect of long-term P-binding therapy with Ca-ket to determine whether P accumulation is the main reason of secondary hyperparathyroidism (HPT) in HD patients or not. Ca-ket was prescribed to 14 HD patients as a soluble preparation in a mean dosage of 4.5 g/day (0.975 g elemental Ca) for a period of 36 months. Serum P continuously dropped from prestudy 2.6 +/- 0.1 (mean +/- SEM) to 1.9 +/- 0.07 mmol/l (p < 0.001), whereas serum Ca increased from 2.2 +/- 0.1 to 2.47 +/- 0.08 mmol/l (p < 0.05). Thus, Ca/P ratio in serum converted significantly from 0.91 +/- 0.02 (prestudy) to 1.28 +/- 0.01 (p < 0.001). Intact parathyroid hormone (iPTH) continuously normalized in all patients from 29 +/- 5 to 8 +/- 2 pmol/l (p < 0.001). The present data show that long-term treatment with Ca-ket normalizes secondary HPT by simultaneously P binding and correcting Ca/P ratio in serum without vitamin D treatment.

Viscoelastic behavior of basaltic ash from Stromboli volcano inferred from intermittent compression experiments

NASA Astrophysics Data System (ADS)

Kurokawa, A. K.; Miwa, T.; Okumura, S.; Uesugi, K.

2017-12-01

After ash-dominated Strombolian eruption, considerable amount of ash falls back to the volcanic conduit forming a dense near-surface region compacted by weights of its own and other fallback clasts (Patrick et al., 2007). Gas accumulation below this dense cap causes a substantial increase in pressure within the conduit, causing the volcanic activity to shift to the preliminary stages of a forthcoming eruption (Del Bello et al., 2015). Under such conditions, rheology of the fallback ash plays an important role because it controls whether the fallback ash can be the cap. However, little attention has been given to the point. We examined the rheology of ash collected at Stromboli volcano via intermittent compression experiments changing temperature and compression time/rate. The ash deformed at a constant rate during compression process, and then it was compressed without any deformation during rest process. The compression and rest processes repeated during each experiment to see rheological variations with progression of compaction. Viscoelastic changes during the experiment were estimated by Maxwell model. The results show that both elasticity and viscosity increases with decreasing porosity. On the other hand, the elasticity shows strong rate-dependence in the both compression and rest processes while the viscosity dominantly depends on the temperature, although the compression rate also affects the viscosity in the case of the compression process. Thus, the ash behaves either elastically or viscously depending on experimental process, temperature, and compression rate/time. The viscoelastic characteristics can be explained by magnitude relationships between the characteristic relaxation times and times for compression and rest processes. This indicates that the balance of the time scales is key to determining the rheological characteristics and whether the ash behaves elastically or viscously may control cyclic Strombolian eruptions.

Alpha-catenin-dependent recruitment of the centrosomal protein CAP350 to adherens junctions allows epithelial cells to acquire a columnar shape.

PubMed

Gavilan, Maria P; Arjona, Marina; Zurbano, Angel; Formstecher, Etienne; Martinez-Morales, Juan R; Bornens, Michel; Rios, Rosa M

2015-03-01

Epithelial morphogenesis involves a dramatic reorganisation of the microtubule cytoskeleton. How this complex process is controlled at the molecular level is still largely unknown. Here, we report that the centrosomal microtubule (MT)-binding protein CAP350 localises at adherens junctions in epithelial cells. By two-hybrid screening, we identified a direct interaction of CAP350 with the adhesion protein α-catenin that was further confirmed by co-immunoprecipitation experiments. Block of epithelial cadherin (E-cadherin)-mediated cell-cell adhesion or α-catenin depletion prevented CAP350 localisation at cell-cell junctions. Knocking down junction-located CAP350 inhibited the establishment of an apico-basal array of microtubules and impaired the acquisition of columnar shape in Madin-Darby canine kidney II (MDCKII) cells grown as polarised epithelia. Furthermore, MDCKII cystogenesis was also defective in junctional CAP350-depleted cells. CAP350-depleted MDCKII cysts were smaller and contained either multiple lumens or no lumen. Membrane polarity was not affected, but cortical microtubule bundles did not properly form. Our results indicate that CAP350 may act as an adaptor between adherens junctions and microtubules, thus regulating epithelial differentiation and contributing to the definition of cell architecture. We also uncover a central role of α-catenin in global cytoskeleton remodelling, in which it acts not only on actin but also on MT reorganisation during epithelial morphogenesis.

Alpha-catenin-Dependent Recruitment of the Centrosomal Protein CAP350 to Adherens Junctions Allows Epithelial Cells to Acquire a Columnar Shape

PubMed Central

Zurbano, Angel; Formstecher, Etienne; Martinez-Morales, Juan R.; Bornens, Michel; Rios, Rosa M.

2015-01-01

Epithelial morphogenesis involves a dramatic reorganisation of the microtubule cytoskeleton. How this complex process is controlled at the molecular level is still largely unknown. Here, we report that the centrosomal microtubule (MT)-binding protein CAP350 localises at adherens junctions in epithelial cells. By two-hybrid screening, we identified a direct interaction of CAP350 with the adhesion protein α-catenin that was further confirmed by co-immunoprecipitation experiments. Block of epithelial cadherin (E-cadherin)-mediated cell-cell adhesion or α-catenin depletion prevented CAP350 localisation at cell-cell junctions. Knocking down junction-located CAP350 inhibited the establishment of an apico-basal array of microtubules and impaired the acquisition of columnar shape in Madin-Darby canine kidney II (MDCKII) cells grown as polarised epithelia. Furthermore, MDCKII cystogenesis was also defective in junctional CAP350-depleted cells. CAP350-depleted MDCKII cysts were smaller and contained either multiple lumens or no lumen. Membrane polarity was not affected, but cortical microtubule bundles did not properly form. Our results indicate that CAP350 may act as an adaptor between adherens junctions and microtubules, thus regulating epithelial differentiation and contributing to the definition of cell architecture. We also uncover a central role of α-catenin in global cytoskeleton remodelling, in which it acts not only on actin but also on MT reorganisation during epithelial morphogenesis. PMID:25764135

On the potential of a new IVUS elasticity modulus imaging approach for detecting vulnerable atherosclerotic coronary plaques: In vitro vessel phantom study

PubMed Central

Le Floc’h, Simon; Cloutier, Guy; Finet, Gérard; Tracqui, Philippe; Pettigrew, Roderic I.; Ohayon, Jacques

2016-01-01

Peak cap stress amplitude is recognized as a good indicator of vulnerable plaque (VP) rupture. However, such stress evaluation strongly relies on a precise, but still lacking, knowledge of the mechanical properties exhibited by the plaque components. As a first response to this limitation, our group recently developed, in a previous theoretical study, an original approach, called iMOD, which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields. In the present in vitro experimental study, conducted on PVA-C arterial phantoms, we investigate the benefit of coupling the iMOD procedure with the acquisition of intravascular ultrasound (IVUS) measurements for detection of VP. Our results show that the combined iMOD-IVUS strategy : 1) successfully detected and quantified soft inclusion contours with high positive predictive values and sensitivities of 89.7 ± 3.9% and 81.5 ± 8.8 %, respectively, 2) estimated reasonably cap thicknesses larger than ~300 µm, but underestimated thinner caps, and 3) quantified satisfactorily Young's modulus of hard medium (mean value of 109.7 ± 23.7 kPa instead of 145.4 ± 31.8 kPa), but overestimated the stiffness of soft inclusions (mean Young`s moduli of 31.4 ± 9.7 kPa instead of 17.6 ± 3.4 kPa). All together, these results demonstrate a promising benefit of the new iMOD-IVUS clinical imaging method for in vivo VP detection. PMID:20826899

Magnesium Induced Nucleophile Activation in the Guanylyltransferase mRNA Capping Enzyme

PubMed Central

Swift, Robert V.; Ong, Chau D.; Amaro, Rommie E.

2012-01-01

The messenger RNA guanylyltransferase, or mRNA capping enzyme, co-transcriptionally caps the 5′-end of nascent mRNA with GMP during the second in a set of three enzymatic reactions that result in the formation of an N7-methyl guanosine cap during mRNA maturation. The mRNA capping enzyme is characterized, in part, by a conserved lysine nucleophile that attacks the alpha-phosphorous atom of GTP, forming a lysine-GMP intermediate. Experiments have firmly established that magnesium is required for efficient intermediate formation, but have provided little insight into the requirement’s molecular origins. Using empirical and thermodynamic integration pKa estimates, along with conventional MD simulations, we show that magnesium binding likely activates the lysine nucleophile by increasing its acidity and by biasing the deprotonated nucleophile into conformations conducive to intermediate formation. These results provide additional functional understanding of an important enzyme in the mRNA transcript life cycle and allow functional analogies to be drawn that affect our understanding of the metal dependence of related superfamily members. PMID:23205906

Clinical audit project in undergraduate medical education curriculum: an assessment validation study

PubMed Central

Steketee, Carole; Mak, Donna

2016-01-01

Objectives To evaluate the merit of the Clinical Audit Project (CAP) in an assessment program for undergraduate medical education using a systematic assessment validation framework. Methods A cross-sectional assessment validation study at one medical school in Western Australia, with retrospective qualitative analysis of the design, development, implementation and outcomes of the CAP, and quantitative analysis of assessment data from four cohorts of medical students (2011- 2014). Results The CAP is fit for purpose with clear external and internal alignment to expected medical graduate outcomes.  Substantive validity in students’ and examiners’ response processes is ensured through relevant methodological and cognitive processes. Multiple validity features are built-in to the design, planning and implementation process of the CAP.  There is evidence of high internal consistency reliability of CAP scores (Cronbach’s alpha > 0.8) and inter-examiner consistency reliability (intra-class correlation>0.7). Aggregation of CAP scores is psychometrically sound, with high internal consistency indicating one common underlying construct.  Significant but moderate correlations between CAP scores and scores from other assessment modalities indicate validity of extrapolation and alignment between the CAP and the overall target outcomes of medical graduates.  Standard setting, score equating and fair decision rules justify consequential validity of CAP scores interpretation and use. Conclusions This study provides evidence demonstrating that the CAP is a meaningful and valid component in the assessment program. This systematic framework of validation can be adopted for all levels of assessment in medical education, from individual assessment modality, to the validation of an assessment program as a whole.  PMID:27716612

Clinical audit project in undergraduate medical education curriculum: an assessment validation study.

PubMed

Tor, Elina; Steketee, Carole; Mak, Donna

2016-09-24

To evaluate the merit of the Clinical Audit Project (CAP) in an assessment program for undergraduate medical education using a systematic assessment validation framework. A cross-sectional assessment validation study at one medical school in Western Australia, with retrospective qualitative analysis of the design, development, implementation and outcomes of the CAP, and quantitative analysis of assessment data from four cohorts of medical students (2011- 2014). The CAP is fit for purpose with clear external and internal alignment to expected medical graduate outcomes.  Substantive validity in students' and examiners' response processes is ensured through relevant methodological and cognitive processes. Multiple validity features are built-in to the design, planning and implementation process of the CAP.  There is evidence of high internal consistency reliability of CAP scores (Cronbach's alpha > 0.8) and inter-examiner consistency reliability (intra-class correlation>0.7). Aggregation of CAP scores is psychometrically sound, with high internal consistency indicating one common underlying construct.  Significant but moderate correlations between CAP scores and scores from other assessment modalities indicate validity of extrapolation and alignment between the CAP and the overall target outcomes of medical graduates.  Standard setting, score equating and fair decision rules justify consequential validity of CAP scores interpretation and use. This study provides evidence demonstrating that the CAP is a meaningful and valid component in the assessment program. This systematic framework of validation can be adopted for all levels of assessment in medical education, from individual assessment modality, to the validation of an assessment program as a whole.

Implications of Large Elastic Thicknesses for the Composition and Current Thermal State of Mars

NASA Astrophysics Data System (ADS)

Grott, M.; Breuer, D.

2008-12-01

The elastic lithosphere thickness at the Martian north polar cap has recently been constrained using radar sounding data obtained by SHARAD, the shallow radar onboard the Mars Reconnaissance Orbiter. Analysis of the SHARAD radargrams showed that the amount of deflection caused by ice loading at the polar caps is negligible - less than 100 m. Quantitative analysis yielded a lower bound on the elastic lithosphere thickness Te of 300 km, a value twice as large as previous estimates from theoretical considerations and flexure studies. Such large elastic thicknesses are only compatible with the planet's thermal evolution if the planetary interior is relatively cold and this could have direct bearing on the admissible amount of radioactive elements in the Martian interior. On the other hand, if the concentration of heat producing elements in the Martian interior is indeed reduced, the resulting low interior temperatures could possibly inhibit partial mantle melting and magmatism. However, geological evidence suggests that Mars has been volcanically active in the recent past. We have investigated the Martian thermal evolution and identified models which are consistent with a present day elastic thickness in excess of 300 km. We find that a wet mantle rheology is best compatible with the observed elastic thicknesses, but in this case the bulk concentration of heat producing elements in the silicate fraction cannot exceed 50 % of the chondritic concentration if 50 % of the radioacitve elements are concentrated in the crust. Furthermore, due to the efficient cooling of the planet for a wet mantle rheology, recent volcanism can only be explained by hydrous mantle melting. This requires the mantle water content to exceed 1500 ppm and although this is within the range reported for the shergottite parent magmas, it is certainly on the boundary of the plausible parameter range. If a dry mantle rheology is assumed, bulk Mars does not need to be sub-chondritic, but at least 70 % of the radiogenic elements need to be concentrated in the crust to be consistent with the large elastic thicknesses. For a dry mantle, recent volcanism could be driven by decompression melting in the heads of strong mantle plumes which are present in numerical simulations of mantle convection if the viscosity is strongly pressure dependent or endothermic phase transitions are present near the core-mantle boundary.

Guanosine 5'-triphosphate binding protein (G/sub i/) and two additional pertussis toxin substrates associated with muscarinic receptors in rat heart myocytes: characterization and age dependency

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

Moscona-Amir, E.; Henis, Y.I.; Sokolovsky, M.

1988-07-12

The coupling of muscarinic receptors with G-proteins was investigated in cultured myocytes prepared from the hearts of newborn rats. The coupling was investigated in both young (5 days after plating) and aged (14 days after plating) cultures, in view of the completely different effects of 5'-guanylyl imidodiphosphate (Gpp(NH)p) on muscarinic agonist binding to homogenates from young vs aged cultures. Pretreatment of cultures from both ages by Bordetella pertussis toxin (IAP) was found to eliminate any Gpp(NH)p effect on carbamylcholine binding. IAP by itself induced a rightward shift in the carbamylcholine competition curve in homogenates from aged cultures, but no suchmore » effect was observed in homogenates from young cultures. IAP-catalyzed (/sup 32/P)ADP-ribosylation of membrane preparations from young and aged cultures revealed major differences between them. Young cultures exhibited a major IAP substrate at 40 kDa, which was also recognized by anti-..cap alpha../sub i/ antibodies, and two novel IAP substrates at 28 and 42 kDa, which were weakly ADP-ribosylated by the toxin and were not recognized with either anti-..cap alpha../sub i/ or anti-..cap alpha../sub 0/ antibodies. In aged cultures, only the 40-kDa band (ribosylated to a lower degree) was detected. The parallel age-dependent changes in the three IAP substrates (28, 40, and 42 kDa) and in the interactions of the G-protein(s) with the muscarinic receptors strongly suggest close association between the two phenomena. All of these age-dependent changes in the G-protein related parameters were prevented by phosphatidylcholine-liposome treatment of the aged cultures. The role of the membrane lipid composition in these phenomena is discussed.« less

Host-pathogen interactions. XXIX. Oligogalacturonides released from sodium polypectate by endopolygalacturonic acid lyase are elicitors of phytoalexins in soybean. [Glycine max L

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

Davis, K.R.; Darvill, A.G.; Albersheim, P.

1986-02-01

Recent studies have demonstrated that an apparently homogeneous preparation of an ..cap alpha..-1,4-D-endopolygalacturonic acid lyase (EC 4.2,2.2) isolated from the phytopathogenic bacterium Erwinia carotovora induced phytoalexin accumulation in cotyledons of soybean (Glycine max (L.) Merr. cv Wayne) and that this pectin-degrading enzyme released heat-stable elicitors of phytoalexins from soybean cell walls, citrus pectin, and sodium polypectate. The present paper reports the purification, by anion-exchange chromatography on QAE-Sephadex columns followed by gel-permeation chromatography on a Bio-Gel P-6 column, of the two fractions with highest specific elicitor activity present in a crude elicitor-preparation obtained by lyase treatment of sodium polypectate. Structural analysismore » of the fraction with highest specific elicitor activity indicated that the major, if not only, component was a decasaccharide of ..cap alpha..-1,4-D-galactosyluronic acid that contained the expected product of lyase cleavage, 4-deoxy-..beta..-L-5-threo-hexopyranos-4-enyluronic acid (4,5-unsaturated galactosyluronic acid), at the nonreducing terminus. This modified decagalacturonide fraction exhibited half-maximum and maximum elicitor activity at 1 microgram/cotyledon (6 micromolar) and 5 micrograms/cotyledon (32 micromolar) galactosyluronic acid equivalents, respectively. Reducing 90 to 95% of the carboxyl groups of the galactosyluronic acid residues abolished the elicitor activity of the decagalacturonide fraction. The second most elicitor-active fraction contained mostly undeca-..cap alpha..-1,4-D-galactosyluronic acid that contained 4,5-unsaturated galactosyluronic acid at the nonreducing termini. This fraction exhibited half-maximum and maximum elicitor activity at approximately 3 micrograms/cotyledon (17 micromolar) and 6 micrograms/cotyledon (34 micromolar) galactosyluronic acid equivalents, respectively.« less

Inhibition of metabolism and DNA binding of polycyclic aromatic hydrocarbons (PAHs) by plant phenols in epidermis of SENCAR mice

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

Das, M.; Bik, D.P.; Bickers, D.R.

1986-03-05

Naturally occurring plant phenols such as tannic acid (TA), quercetin (QT), myricetin (MY) and anthraflavic acid (AA) have been shown to inhibit the mutagenicity of several bay-region diolepoxides of PAHs. Since skin is a target for PAH carcinogenesis, they investigated the effect of these plant phenols on epidermal aryl hydrocarbon hydroxylase (AHH) activity and the binding of PAHs to DNA in SENCAR mice. Each of the plant phenols tested was found to be an in vitro and in vivo inhibitor of epidermal AHH activity with I/sub 50/ values ranging from 4.4 x 10/sup -5/ - 12.4 x 10/sup -5/M inmore » control and 3-methylcholanthrene (MCA) pretreated skin. On an equimolar basis TA was the most potent inhibitor with a Ki of 81 ..mu..M. Incubation of TA, QT, MY and AA with epidermal microsomes resulted in varying degrees of inhibition of enzyme mediated covalent binding of benzo(a)pyrene (BP) to calf thymus DNA. TA (25 ..mu..M) showed maximum inhibition (64%). A single topical application (12 ..mu..mol) of TA, QT, MY and AA resulted in significant decrease in the binding of BP, BP-7,8-diol and 7,12-dimethylbenz(a)anthracene to epidermal DNA. The formation of (+)-7..beta..,8..cap alpha..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydro-BP-deoxyguanine adduct in epidermis was significantly reduced (62-86%) following topical application of the plant phenols. Their results suggest that some of these plant phenols have substantial though variable potential to modify the risk of PAHs induced skin carcinogenicity.« less

Bonding in the first-row diatomic molecules within the local spin-density approximation

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

Painter, G.S.; Averill, F.W.

1982-08-15

The Hohenberg-Kohn-Sham density-functional equations in the local spin-density approximation (LSDA) have been solved with essentially no loss of accuracy for dimers of the first row of the Periodic Table with the use of a fully-self-consistent spin-polarized Gaussian-orbital approach. Spectroscopic constants (binding energies, equilibrium separations, and ground-state vibrational frequencies) have been derived from the calculated potential-energy curves. Intercomparison of results obtained using the exchange-correlation functionals of Slater (scaled exchange or X..cap alpha..), Gunnarsson and Lundqvist (GL), and Vosko, Wilk, and Nusair (VWN) permits assessment of the relative merits of each and serves to identify general shortcomings in the LSDA. Basic trendsmore » are similar for each functional, but the treatment of the spin dependence of the exchange-correlation energy in the GL and VWN functionals yields a variation of the binding energy across the series which is more systematic than that in the X..cap alpha.. approximation. Agreement between the present results and those of Dunlap, Connolly, and Sabin in the X..cap alpha.., approximation confirms the accuracy of the variational charge-density-fit procedure used in the latter work. The refinements in correlation treatment within the VWN functional are reflected in improvements in binding energies which are only slight for most dimers in the series. This behavior is attributed to the error remaining in the exchange channel within the LSDA and demonstrates the necessity for self-interaction corrections for more accurate binding-energy determinations. Within the current LSDA, absolute accuracies of the VWN functional for the first-row dimers are within 2.3 eV for binding energies, 0.07 a.u. for bond lengths, and approx.200 cm/sup -1/ for vibrational frequencies.« less

ESR study of electron reactions with esters and triglycerides

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

Sevilla, M.D.; Morehouse, K.M.; Swarts, S.

1981-04-02

Reactions which occurred after electron attachment at 77K to a number of small carboxylic acid esters and triglycerides in an aqueous glass are reported. Most ester anions are found to decay on warming to form alkyl radicals by ..beta.. scission: RC(O/sup -/)OR' ..-->.. RCO/sub 2//sup -/ + R'.. The alkyl radical (R'.) produced by annealing is found to abstract hydrogen from the parent ester at an ..cap alpha..-carbon site, R'.+ R''CH/sub 2/CO/sub 2/R' ..-->.. R''CHCO/sub 2/R', or in the case of ethyl formate from the formate hydrogen, CH/sub 3/CH/sub 2/.+ HCO/sub 2/C/sub 2/H/sub 5/ ..-->.. C/sub 2/H/sub 6/ +.CO/sub 2/C/submore » 2/H/sub 5/. Results found for the methyl formate anion suggest hydrogen abstraction by the anion itself may compete with alkyl radical formation. The anion of the triglyceride triacetin is found to undergo an analogous mechanism to the ester anions producing the propane diol diester radical, .CH/sub 2/CH(Ac)CH/sub 2/(Ac), Ac = acetate. This species subsequently abstracts hydrogen from the parent compound to produce the ..cap alpha..-carbon radical, .CH/sub 2/CO/sub 2/R. Results found after annealing the tripropionin radical anion give evidence for abstraction from the ..cap alpha.. carbon in the propionate side groups producing CH/sub 3/CHCO/sub 2/R. Studies of a ..gamma..-irradiated ester (ethyl myristate) and two triglycerides (tripalmitin and tristearin) yield results which suggest that the mechanism of ester anion decay found in aqueous glasses applies to ..gamma..-irradiated neat long-chain esters and triglycerides. Results found in this work are compared to the results of product analysis.« less

Structural elucidation of the Brucella melitensis M antigen by high-resolution NMR at 500 MHz

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

Bundle, D.R.; Cherwonogrodzky, J.W.; Perry, M.B.

The Brucella M antigen from the species type strain Brucella melitensis 16M has been identified as a component of the cell wall lipopolysaccharide (LPS). O polysaccharide liberated from this LPS by mild acid hydrolysis exhibited M activity in serological tests and was shown to be a homopolymer of 4-formamido-4,6-dideoxy-..cap alpha..-D-mannopyranosyl residues arranged in an oligosaccharide repeating unit as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the native lipopolysaccharide. Structural analysis of the O polysaccharide by NMR methods was difficult due to apparent microheterogeneity of the repeating unit, which was in fact caused by the presence of rotational isomers ofmore » the N-formyl moiety. This problem was resolved by chemical modification of the polysaccharide to its amino and N-acetyl derivatives, the 500-MHz /sup 1/H and 125-MHz /sup 13/C NMR spectra of which could be analyzed in terms of a unique structure through application of pH-dependent ..beta..-shifts and two-dimensional techniques that included COSY, relayed COSY, and NOESY experiments together with heteronuclear C/H shift correlation spectroscopy. On the basis of these experiments and supported by methylation and periodate oxidation data, the structure of the M polysaccharide was determined as a linear polymer of unbranched pentasaccharide repeating units consisting of four 1,2-linked and one 1,3-lined 4,6-dideoxy-4-formamido-..cap alpha..-D-mannopyranosyl residues. The marked structural similarity of the M antigen and the A antigen, which is known to be a 1,2-linked homopolysaccharide of 4,6-dideoxy-4-formamido-..cap alpha..-D-mannopyranosyl units, accounts for cross-serological reactions of the two and the long-standing confusion surrounding the nature of their antigenic determinants.« less

Three-dimensional elastic-plastic finite-element analyses of constraint variations in cracked bodies

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Bigelow, C. A.; Shivakumar, K. N.

1993-01-01

Three-dimensional elastic-plastic (small-strain) finite-element analyses were used to study the stresses, deformations, and constraint variations around a straight-through crack in finite-thickness plates for an elastic-perfectly plastic material under monotonic and cyclic loading. Middle-crack tension specimens were analyzed for thicknesses ranging from 1.25 to 20 mm with various crack lengths. Three local constraint parameters, related to the normal, tangential, and hydrostatic stresses, showed similar variations along the crack front for a given thickness and applied stress level. Numerical analyses indicated that cyclic stress history and crack growth reduced the local constraint parameters in the interior of a plate, especially at high applied stress levels. A global constraint factor alpha(sub g) was defined to simulate three-dimensional effects in two-dimensional crack analyses. The global constraint factor was calculated as an average through-the-thickness value over the crack-front plastic region. Values of alpha(sub g) were found to be nearly independent of crack length and were related to the stress-intensity factor for a given thickness.

Increased helix and protein stability through the introduction of a new tertiary hydrogen bond.

PubMed

Peterson, R W; Nicholson, E M; Thapar, R; Klevit, R E; Scholtz, J M

1999-03-12

In an effort to quantify the importance of hydrogen bonding and alpha-helix formation to protein stability, a capping box motif was introduced into the small phosphocarrier protein HPr. Previous studies had confirmed that Ser46, at the N-cap position of the short helix-B in HPr, serves as an N-cap in solution. Thus, only a single-site mutation was required to produce a canonical S-X-X-E capping box: Lys49 at the N3 position was substituted with a glutamic acid residue. Thermal and chemical denaturation studies on the resulting K49E HPr show that the designed variant is approximately 2 kcal mol-1 more stable than the wild-type protein. However, NMR studies indicate that the side-chain of Glu49 does not participate in the expected capping H-bond interaction, but instead forms a new tertiary H-bond that links helix-B to the four-stranded beta-sheet of HPr. Here, we demonstrate that a strategy in which new non-native H-bonds are introduced can generate proteins with increased stability. We discuss why the original capping box design failed, and compare the energetic consequences of the new tertiary side-chain to main-chain H-bond with a local (helix-capping) side-chain to main-chain H-bond on the protein's global stability. Copyright 1999 Academic Press.

Supramolecular Inclusion in Cyclodextrins: A Pictorial Spectroscopic Demonstration

ERIC Educational Resources Information Center

Haldar, Basudeb; Mallick, Arabinda; Chattopadhyay, Nitin

2008-01-01

A spectroscopic experiment is presented that reveals that the hydrophobically end-modified water-soluble polymeric fluorophore, pyrene end-capped poly(ethylene oxide) (PYPY), interacts differently with [alpha], [beta], and [gamma]-cyclodextrins (CD) to form supramolecular inclusion complexes. The emission spectrum of PYPY in aqueous solution shows…

A parametric study of planform and aeroelastic effects on aerodynamic center, alpha- and q-stability derivatives

NASA Technical Reports Server (NTRS)

Roskam, J.; Lan, C.

1973-01-01

Summarized are the aerodynamic center, alpha and q- aeroelastic effects on fighter-type aircraft in the 18,700 N gross range. The results indicate that with proper tailoring of planform (fixed or variable sweep), stiffner and elastic axis location it is possible to minimize trim requirements between selected extreme conditions. The inertial effects were found to be small for this class of aircraft.

Characterization of Ti6Al7Nb alloy foams surface treated in aqueous NaOH and CaCl2 solutions.

PubMed

Bütev, Ezgi; Esen, Ziya; Bor, Şakir

2016-07-01

Ti6Al7Nb alloy foams having 53-73% porosity were manufactured via evaporation of magnesium space holders. A bioactive 1µm thick sodium hydrogel titanate layer, NaxH2-xTiyO2y+1, formed after 5M NaOH treatment, was converted to crystalline sodium titanate, Na2TiyO2y+1, as a result of post-heat treatment. On the other hand, subsequent CaCl2 treatment of NaOH treated specimens induced calcium titanate formation. However, heat treatment of NaOH-CaCl2 treated specimens led to the loss of calcium and disappearance of the titanate phase. All of the aforementioned surface treatments reduced yield strengths due to the oxidation of the cell walls of the foams, while elastic moduli remained mostly unchanged. Accordingly, equiaxed dimples seen on the fracture surfaces of as-manufactured foams turned into relatively flat and featureless fracture surfaces after surface treatments. On the other hand, Ca- and Na-rich coating preserved their mechanical stabilities and did not spall during fracture. The relation between mechanical properties of foams and macro-porosity fraction were found to obey a power law. The foams with 63 and 73% porosity met the desired biocompatibility requirements with fully open pore structures and elastic moduli similar to that of bone. In vitro tests conducted in simulated body fluid (SBF) showed that NaOH-heat treated surfaces exhibit the highest bioactivity and allow the formation of Ca-P rich phases having Ca/P ratio of 1.3 to form within 5 days. Although Ca-P rich phases formed only after 15 days on NaOH-CaCl2 treated specimens, the Ca/P ratio was closer to that of apatite found in bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of branching on the elasticity of actin networks

PubMed Central

Pujol, Thomas; du Roure, Olivia; Fermigier, Marc; Heuvingh, Julien

2012-01-01

Actin filaments play a fundamental role in cell mechanics: assembled into networks by a large number of partners, they ensure cell integrity, deformability, and migration. Here we focus on the mechanics of the dense branched network found at the leading edge of a crawling cell. We develop a new technique based on the dipolar attraction between magnetic colloids to measure mechanical properties of branched actin gels assembled around the colloids. This technique allows us to probe a large number of gels and, through the study of different networks, to access fundamental relationships between their microscopic structure and their mechanical properties. We show that the architecture does regulate the elasticity of the network: increasing both capping and branching concentrations strongly stiffens the networks. These effects occur at protein concentrations that can be regulated by the cell. In addition, the dependence of the elastic modulus on the filaments’ flexibility and on increasing internal stress has been studied. Our overall results point toward an elastic regime dominated by enthalpic rather than entropic deformations. This result strongly differs from the elasticity of diluted cross-linked actin networks and can be explained by the dense dendritic structure of lamellipodium-like networks. PMID:22689953

Disc valve for sampling erosive process streams

DOEpatents

Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

1984-08-16

This is a patent for a disc-type, four-port sampling valve for service with erosive high temperature process streams. Inserts and liners of ..cap alpha..-silicon carbide respectively, in the faceplates and in the sampling cavities, limit erosion while providing lubricity for a smooth and precise operation. 1 fig.

Spherical nanoindentation stress-strain curves of commercially pure titanium and Ti-6Al-4V

DOE Data Explorer

Weaver, Jordan S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Priddy, Matthew W. [Georgia Inst. of Technology, Atlanta, GA (United States); McDowell, David L. [Georgia Inst. of Technology, Atlanta, GA (United States); Kalidindi, Surya R. [Georgia Inst. of Technology, Atlanta, GA (United States)

2016-07-27

Spherical nanoindentation combined with electron back-scattered diffraction was employed to characterize the grain-scale elastic and plastic anisotropy of single crystal alpha-Ti for commercially pure (CP-Ti) and alloyed (Ti-64) titanium. In addition, alpha-beta Ti (single colony) grains were characterized. The data set includes the nanoindentation force, displacement, and contact stiffness, the nanoindentation stress-strain analysis, and the alpha-Ti crystal orientations. Details of the samples and experimental protocols can be found in Weaver et al. (2016) Acta Materialia doi:10.1016/j.actamat.2016.06.053.

Importance of the lid and cap domains for the catalytic activity of gastric lipases.

PubMed

Miled, N; Bussetta, C; De caro, A; Rivière, M; Berti, L; Canaan, S

2003-09-01

Human gastric lipase (HGL) is an enzyme secreted by the stomach, which is stable and active despite the highly acidic environment. It has been clearly established that this enzyme is responsible for 30% of the fat digestion processes occurring in human. This globular protein belongs to the alpha/beta hydrolase fold family and its catalytic serine is deeply buried under a domain called the extrusion domain, which is composed of a 'cap' domain and a segment consisting of 58 residues, which can be defined as a lid. The exact roles played by the cap and the lid domains during the catalytic step have not yet been elucidated. We have recently solved the crystal structure of the open form of the dog gastric lipase in complex with a covalent inhibitor. The detergent molecule and the inhibitor were mimicking a triglyceride substrate that would interact with residues belonging to both the cap and the lid domains. In this study, we have investigated the role of the cap and the lid domains, using site-directed mutagenesis procedures. We have produced truncated mutants lacking the lid and the cap. After expressing these mutants and purifying them, their activity was found to have decreased drastically in comparison with the wild type HGL. The lid and the cap domains play an important role in the catalytic reaction mechanism. Based on these results and the structural data (open form of DGL), we have pointed out the cap and the lid residues involved in the binding with the lipidic substrate.

Hybrid calcium phosphate coatings for implants

NASA Astrophysics Data System (ADS)

Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

2016-08-01

Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

Measurements of elastic and inelastic scattering cross-sections using monoenergetic Kα radiation

NASA Astrophysics Data System (ADS)

Rao, Donepudi V.; Seltzer, S. M.; Hubbell, John H.; Cesareo, Roberto; Brunetti, Antonio; Gigante, Giovanni E.

2000-12-01

Elastic and inelastic scattering cross-sections for low, medium and high Z atoms are measured in vacuum using an x- ray tube with a secondary targets as an excitation source. Monoenergetic K(alpha) radiation emitted from the secondary target is used to excite the sample. Monoenergetic radiation emitted from the secondary target is used to excite the sample. Monoenergetic radiation is also produced using two secondary targets coupled to an x-ray tube and the radiation from the second target of the system is used to excite the sample. Elastic and inelastic scattering of K(alpha) X-ray line energies of the secondary target by the sample are recorded with Hp Ge and Si(Li) detectors. Using this system the degree of monochromaticity of the secondary emission and the geometrical effects of the measuring system is estimated. The efficiency is large because the secondary target acts as a converter. Experimental results based on this system will be presented and compared with theoretical estimates. The importance of the dat and the potential use of the system for few applications in the field of medicine and archaeometry will also be presented.

THE SCATTERING OF POSITIVE 120 MEV PIONS ON PROTONS. PART I. PART II

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

Loria, A.; Mittner, P.; Santangelo, R.

1961-04-11

An investigation of the elastic scattering of 120 Mev positive pions by protons is described in which a liquid propane chamber was exposed to the CERN 600 Mev synchrocyclotron. The results refer to 5405 selected events in which the contamination from scattering on carbon nuclei is shown to be negligible. The values obtained for the phase shifts are: alpha /sub 3//sub 1/ = -2.60 deg plus or minus 0.69 deg , alpha /sub 3/= -11.05 deg plus or minus 1.32 deg , alpha /sub 3//sub 3/ = +31.67 deg plus or minus O.O1 deg . The value of alpha /submore » 3/ differs significantly from that expected if the linear dependence of alpha /sub 3/ on the momentum, which has been proposed by some authors, is assumed. (auth)« less

Laser surface treatment for porous and textured Ca-P bio-ceramic coating on Ti-6Al-4V.

PubMed

Paital, Sameer R; Dahotre, Narendra B

2007-12-01

In the present paper the feasibility of depositing a porous calcium phosphate (CaP) bio-ceramic coating using a continuous wave Nd:YAG laser on a Ti-6Al-4V substrate has been demonstrated. The advantages offered by such porous bio-ceramic coating are its inertness combined with the mechanical stability of the highly convoluted interface that develops when bone grows into the pores of ceramic. The formation of different phases with varying laser fluences is studied using x-ray diffraction (XRD). A quantitative estimation of the crystallite size and relative amounts of Ti and other predominant phases such as TiO(2) and alpha-tricalcium phosphate (alpha-TCP) were obtained. An increase in the crystallite size with increasing laser fluence is observed for all the above three phases. It is observed that TiO(2) is the predominant phase for all laser fluences and there is an increase in the alpha-TCP phase with increasing laser fluence. Surface porosity measurements indicated a decreasing trend with increasing laser fluence. Microhardness measurements in the cross section of samples showed a maximum hardness within the coating. The bioactivity of the coatings was further demonstrated by the formation of an apatite-like layer on the surface of the sample after being immersed in a simulated biofluid.

Yang-Lee zeros, Julia sets, and their singularity spectra

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

Hu, B.; Lin, B.

1989-05-01

We have studied the global scaling properties of the Julia sets of the Yang-Lee zeros of the s-state Potts model on the diamond hierarchical lattice. The singularity spectrum f(..cap alpha..) and the generalized dimension D/sub q/ are calculated for different s values. General observations are made on their variations.

N-(/sup 11/C)-methyl-p-substituted phentermine analogs as potential brain blood flow agents for positron tomography

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

Kizuka, H.; Elmaleh, D.R.; Boudreaux, G.J.

The addition of a methyl group to the ..cap alpha..-position of amphetamine increases both the lipophilicity of the agent and its resistance to metabolism by monoamine oxidase. In addition, since tritium substituted phenteramine analog studies suggested that the p-halo phentermines had a greater concentration in the brain and prolonged retention time, the authors evaluated the biological behavior of positron labeled ..cap alpha..-methylamphetamine (phenteramine) in rats, dogs and monkeys. The N-(/sup 11/C) methyl analogs of p-chloro (I) and p-fluoro (II) phentermines were prepared by methylation of their primary amines using /sup 11/Ch/sub 3/I. Biodistribution studies in rats shows brain uptake ismore » in the range of 1% dose/gr at 5 and 15 min for both agents. The activity in blood and eyes is low. Sequential images of the dogs' brain over 1 hour revealed a clearance of <15%. Images of the monkey brain were also obtained using a MGH positron camera PCR-I.« less

Racemization of alanine by the alanine racemases from Salmonella typhimurium and Bacillus stearothermophilus: energetic reaction profiles

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

Faraci, W.S.; Walsh, C.T.

1988-05-03

Alanine racemases are bacterial pyridoxal 5'-phosphate (PLP) dependent enzymes providing D-alanine as an essential building block for biosynthesis of the peptidoglycan layer of the cell wall. Two isozymic alanine racemases, encoded by the dadB gene and the alr gene, from the Gram-negative mesophilic Salmonella typhimurium and one from the Gram-positive thermophilic Bacillus stearothermophilus have been examined for the racemization mechanism. Substrate deuterium isotope effects and solvent deuterium isotope effects have been measured in both L ..-->.. D and D..-->.. L directions for all three enzymes to assess the degree to which abstraction of the ..cap alpha..-proton or protonation of substratemore » PLP carbanion is limiting in catalysis. Additionally, experiments measuring internal return of ..cap alpha..-/sup 3/H from substrate to product and solvent exchange/substrate conversion experiments in /sup 3/H/sub 2/O have been used with each enzyme to examine the partitioning of substrate PLP carbanion intermediates and to obtain the relative heights of kinetically significant energy barriers in alanine racemase catalysis.« less

Mobilization of tissue cadmium in mice and calves and reversal of cadmium induced tissue damage in calves by zinc

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

Reddy, C.S.; Mohammad, F.K.; Ganjam, V.K.

1987-08-01

Earlier studies demonstrated that simultaneous dietary Zn supplementation to calves fed Cd, significantly decreased the accumulation of Cd in liver, kidney and muscle. However, studies are lacking in evaluating the effectiveness of zinc in reducing Cd-burden in animals with pre-existing tissue Cd-load, a situation encountered in chronic Cd intoxication. This study examined the effects of oral Zn (AnO) on tissue Cd levels in mice. N-acetylcysteine (NAC) and sodium sulfate (SS) were also used to evaluate the effects of providing organic and inorganic sources of sulfur on tissue Cd levels. Following demonstration of reduced Cd levels in tissues of mice receivingmore » antidotal Zn, subsequent investigation was aimed at studying the reversal of Cd-induced changes by Zn. The authors also examined whether Cd-induced reduction in epididymal 5 ..cap alpha..-reductase activity could explain previously reported low levels of circulating dihydrotestosterone (DHT) following Cd treatment. The ability of Zn to reverse the inhibition of 5 ..cap alpha..-reductase activity by Cd was also examined.« less

Study on great northern beans (Phaseolus vulgaris): effect of drum drying process on bean flour properties and effect on gamma radiation on bean starch properties

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

Rayas-Solis, P.

Great Northern bean (Phaseolus vulgaris L.) drum dried flours at native pH of 6.54, pH 6 and 7 showed reduced activities of trypsin inhibitor, ..cap alpha..-amylase inhibitor, hemagglutinating titer, and nitrogen solubility. Electrophoretic analyses showed a slight modification of the native bean proteins, and the presence of at least four trypsin inhibitors. The study of the effect of 2.5-20 kGy irradiation doses on Great Northern beans showed essentially no modification of the electrophoretic mobility of the storage proteins or the trypsin inhibitors. Nitrogen solubility and hemagglutinating activity were essentially unchanged. With the 20 kGy dose, decrease in ..cap alpha..-amylase inhibitormore » activity, decrease reactive/available lysine content, and decrease cooking time of the irradiated beans after 11 months of storage were observed. Taste panel results indicated that the control and 20 kGy irradiated bean were significantly different at 5% level. At 20 kGy dose, the beans developed a partially water soluble brown color.« less

Mutations in a gene encoding the. cap alpha. subunit of a Saccharomyces cerevisiae G protein indicate a role in mating pheromone signaling

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

Jahng, K.Y.; Ferguson, J.; Reed, S.I.

1988-06-01

Mutations which allowed conjugation by Saccharomyces cerevisiae cells lacking a mating pheromone receptor gene were selected. One of the genes defined by such mutations was isolated from a yeast genomic library by complementation of a temperature-sensitive mutation and is identically to the gene GPA1 (also known as SCG1), recently shown to be highly homologous to gene encoding the ..cap alpha.. subunits of mammalian G proteins. Physiological analysis of temperature-sensitive gpal mutations suggests that the encoded G protein is involved in signaling in response to mating pheromones. Mutational disruption of G-protein activity causes cell-cycle arrest in G/sub 1/, deposition of mating-specificmore » cell surface aggultinins, and induction of pheromone-specific mRNa, all of which are responses to pheromone in wild-type cells. In addition, mutants can conjugate without the benefit of mating pheromone or pheromone receptor. A model is presented where the activated G protein has a negative impact on a constitutive signal which normally keeps the pheromone response repressed.« less

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

Downes, R.A.

Galactic plane ultraviolet-excess (uv-excess) objects covering about 1000 square degrees of sky were surveyed. Photographic plates were obtained with both uv and blue filters, to select the uv-excess candidates, which were then observed spectroscopically to determine their classification. Most of the objects selected were nearby early-type stars with low interstellar reddening; however, a collection of hot white dwarfs, subdwarf O (sdO) stars, subdwarf B (sdB) stars, and cataclysmic variables was also found. Photoelectric photometry was obtained for these stars and a statistical analysis was performed to determine the space densities and scale heights for the four classes of objects. Severalmore » interesting objects (or class of objects) were discovered, and data for some of these stars are presented. Among the peculiar objects found are an emission-line white dwarf similar to the pulsating PG 1159 stars, a Population II Wolf-Rayet star, a previously catalogued object with a strong Fe II emission-line spectrum, and a new class of object, resembling the sdB stars, that shows variable strength H..cap alpha.. absorption, with the H..cap alpha.. line sometimes completely filled in.« less

Nucleotide sequence of the gene encoding the nitrogenase iron protein of Thiobacillus ferrooxidans

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

Pretorius, I.M.; Rawlings, D.E.; O'Neill, E.G.

1987-01-01

The DNA sequence was determined for the cloned Thiobacillus ferrooxidans nifH and part of the nifD genes. The DNA chains were radiolabeled with (..cap alpha..-/sup 32/P)dCTP (3000 Ci/mmol) or (..cap alpha..-/sup 35/S)dCTP (400 Ci/mmol). A putative T. ferrooxidans nifH promoter was identified whose sequences showed perfect consensus with those of the Klebsiella pneumoniae nif promoter. Two putative consensus upstream activator sequences were also identified. The amino acid sequence was deduced from the DNA sequence. In a comparison of nifH DNA sequences from T. ferrooxidans and eight other nitrogen-fixing microbes, a Rhizobium sp. isolated from Parasponia andersonii showed the greatest homologymore » (74%) and Clostridium pasteurianum (nifH1) showed the least homology (54%). In the comparison of the amino acid sequences of the Fe proteins, the Rhizobium sp. and Rhizobium japonicum showed the greatest homology (both 86%) and C. pasteurianum (nifH1 gene product) demonstrated the least homology (56%) to the T. ferrooxidans Fe protein.« less

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

Nomura, S.; Enna, S.J.

Tricyclic antidepressants (TCAs) have anticholinergic and ..cap alpha..-adrenergic blocking properties. The present study was undertaken to examine the effects of amitriptyline, imipramine, and desipramine on inositol phosphate accumulation, a brain second messenger system associated with cholinergic and adrenergic receptors. Whereas the TCAs were 28 to 400-fold weaker than atropine as inhibitors of /sup 3/H-QNB binding to brain cholinergic receptors, they were 600 to 2000-fold less active than atropine as inhibitors of carbachol-stimulated IP accumulation in brain. In contrast, the relative potencies of the TCAs and prazosin to inhibit norepinephrine-stimulated IP accumulation and /sup 3/H-prazosin binding appeared to be similar inmore » the two assays. The results suggest pharmacological differences between the cholinergic receptors labeled in the ONB binding assay and those mediating the IP response, whereas the ..cap alpha../sub 1/-adrenergic receptors appear to be similar in the two systems. Since atropine is considered a nonselective muscarinic antagonist, it is possible that the TCAs may differentiate between cholinergic receptor subtypes, which may be an important component of their clinical response.« less

Direct /sup 125/I-radioligand assays for serum progesterone compared with assays involving extraction of serum

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

Ratcliffe, W.A.; Corrie, J.E.T.; Dalziel, A.H.

1982-06-01

Two direct radioimmunoassays for progesterone in 50 ..mu..L of unextracted serum or plasma with assays involving extraction of serum were compared. The direct assays include the use of either danazol at pH 7.4 or 8-anilino-1-naphthalenesulfonic acid at pH 4.0 to displace progesterone from serum binding-proteins. Progesterone is then assayed by using an antiserum to a progesterone 11..cap alpha..-hemisuccinyl conjugate and the radioligand /sup 125/I-labeled progesterone 11..cap alpha..-glucuronyl tyramine, with separation by double-antibody techniques. Direct assays with either displacing agent gave good analytical recovery of progesterone added to human serum, and progesterone values for patients' specimens correlated well (r > 0.96)more » with results of assays involving extraction of serum. Precision was similar with each displacing agent over the working range 2.5-100 nmol/L and superior to that of extraction assays. We conclude that these direct assays of progesterone are analytically valid and more robust, precise, and technically convenient than many conventional methods involving extraction of serum.« less

The single crystal elastic constants of hexagonal SiC to 1000 C

NASA Technical Reports Server (NTRS)

Li, Z.; Bradt, R. C.

1988-01-01

The relationships between the sound velocities in the cubic and hexagonal crystal structures and the tensor transformations for the two structures are applied to determine the elastic stiffnesses for the hexagonal structures of SiC to 1000 C. These results are then applied to calculate the polycrystalline elastic moduli, E and G, and their temperature variations. The calculated values for E and G at 20 C are 420 and 180 GPa; for (dE/dT) and (dG/dT), the values are -0.020 and -0.007 GPa/C, respectively.These agree well with published experimental values for E and G of dense polycrystalline alpha silicon carbides.

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

Hall, J.; Richard, P.; Gray, T.J.

The systematics of single and double K-shell-vacancy production in titanium has been investigated in the limit of zero target thickness (approx.1 ..mu..g/cm/sup 2/) for incident C, N, O, F, Mg, Al, Si, S, and Cl ions over a maximum energy range of 0.5 to 6.5 MeV/amu. This corresponds to collision systems with 0.27< or =Z/sub 1//Z/sub 2/< or =0.77 and 0.24< or =v/sub 1//vK< or =0.85, where v/sub 1/ is the projectile nuclear velocity and vK is the mean velocity of an electron in the target K shell. The present work is divided into four major sections. (1) Single K-shell-vacancymore » production has been investigated by measuring K..cap alpha.. and K..beta.. p satellite x-ray-production cross sections for projectiles incident with no K-shell vacancies. For incident ions with Z/sub 1/> or =9, the contribution due to electron-transfer processes from the target K shell to outer shells of the projectile has also been noted. (2) Single K-shell--to--K-shell electron-transfer cross sections have been obtained indirectly by the measuring of the enhancement in the Ti K x-ray production cross section for bare incident projectiles over ions incident with no initial K-shell vacancies. (3) Double K-vacancy production has been investigated by measuring the K..cap alpha.. hypersatellite intensity in ratio to the total K..cap alpha.. intensity. (4) Double K-shell--to--K-shell electron-transfer cross sections have been obtained indirectly with the use of a procedure similar to that used for single K to K transfer. The measured cross sections have been compared to theoretical models for direct Coulomb ionization and inner-shell electron transfer and have been used to investigate the relative importance of these mechanisms for K-vacancy production in heavy-ion--atom collisions.« less

Absolute configurations of organometallic compounds. III. Structure and absolute configuration of the square-pyramidal complex ((+)/sub 579/-(C/sub 5/H/sub 5/)Mo(CO)/sub 2/(NN*))PF/sub 6/(NN* = Schiff base derived from pyridine-2-carbaldehyde and (S)-(-)-. cap alpha. -phenylethylamine)

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

Bernal, I.; LaPlaca, S.J.; Korp, J.

The structure of (+)/sub 579/-(eta/sup 5/-C/sub 5/H/sub 5/Mo(CO)/sub 2/(NN*))PF/sub 6/ with NN* = the Schiff base derived from pyridine-2-carbaldehyde and (S)-(--)-..cap alpha..-phenylethylamine was determined using standard single-crystal x-ray diffraction methods. The absolute configuration was determined by refinement of the data using the anomalous scattering contributions of Mo and P to a final R(F) = 0.056 for 2634 independent reflections having I greater than 3 sigma (I). The substance crystallizes in the space group P2/sub 1/2/sub 1/2/sub 1/ with unit cell dimensions of a = 12.249 (4), b = 9.236 (3), and c = 20.692 (9) A and Z = 4more » molecules/unit cell. The square-pyramidal coordination of the Mo atom is defined by two carbonyl carbons and two Schiff base nitrogens occupying the four basal plane sites and the five carbons of the eta/sup 5/-C/sub 5/H/sub 5/ ligand in the axial position. The Mo--ligand distances and the bond lengths and angles within the ligands are normal and compare closely with those of recent structure determinations of comparable precision. The Mo atom is 0.95 A above the plane formed by the four basal plane ligands. The conformation of the (S)-..cap alpha..-phenylethyl group with respect to the ligand plane, defined by the pyridine ring, the imine system, and the Mo atom, is discussed. The configuration at the metal atom in the (+)/sub 579/ isomer is specified as (S). The PF/sub 6//sup -/ anion executes large amplitude torsional motion in the lattice, as is commonly the case for this anion when not hydrogen bonded.« less

Biochemistry of snake venom neurotoxins and their application to the study of synapse. [Neurotoxins isolated from venom of the Formosan banded krait

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

Hanley, M.R.

1978-11-01

The crude venom of the Formosan banded krait, Bungarus multicinctus, was separated into eleven lethal protein fractions. Nine fractions were purified to final homogeneous toxins, designated ..cap alpha..-bungarotoxin, ..beta..-bungarotoxin, and toxins 7, 8, 9A, 11, 12, 13, and 14. Three of the toxins, ..cap alpha..-bungarotoxin, 7, and 8, were identified as post-synaptic curarimimetic neurotoxins. The remaining toxins were identified as pre-synaptic neurotoxins. ..cap alpha..-Bungarotoxin, toxin 7, and toxin 8 are all highly stable basic polypeptides of approx. 8000 daltons molecular weight. The pre-synaptic toxins fell into two structural groups: toxin 9A and 14 which were single basic chains of approx.more » 14,000 daltons, and ..beta..-bungarotoxin, and toxins 11 thru 13 which were composed of two chains of approx. 8000 and approx. 13,000 daltons covalently linked by disulfides. All the pre-synaptic neurotoxins were shown to have intrinsic calcium-dependent phospholipase A activities. Under certain conditions, intact synaptic membranes were hydrolyzed more rapidly than protein-free extracted synaptic-lipid liposomes which, in turn, were hydrolyzed more rapidly than any other tested liposomes. It was speculated that cell-surface arrays of phosphatidyl serine/glycolipids created high affinity target sites for ..beta..-bungarotoxin. Single-chain toxins were found to be qualitatively different from the two-chain toxins in their ability to block the functioning of acetylcholine receptors, and were quantitatively different in their enzymatic and membrane disruptive activities. ..beta..-Bungarotoxin was shown to be an extremely potent neuronal lesioning agent. There was no apparent selectivity for cholinergic over non-cholinergic neurons, nor for nerve terminals over cell bodies. It was suggested that ..beta..-bungarotoxin can be considered a useful new histological tool, which may exhibit some regional selectivity.« less

SCATTERING OF NEUTRONS BY $alpha$-PARTICLES AT 14.1 Mev

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

Fasoli, U.; Zago, G.

1963-12-01

The angular distribution of 14.1-Mev neutrons elastically scattered by alpha particles was measured by observing the alpha recoils in a helium-filled cloud chamber. The results are in satisfactory agreement with those previously obtained by others. Inspection of the small-angle region of the measured distribution shows that phase shifts of orbital angular momentum higher than L = 1 are not negligible, although, according to the present experiment, quantitative information on D-waves turns out to be somewhat elusive. The azimuthal angular distribution agrees well with the value P = 0.02 of the neutron beam polarization, as measured by Perkins. (auth)

Effects of End CAP and Aspect Ratio on Transmission of Sound across a Truss-Like Periodic Double Panel

NASA Astrophysics Data System (ADS)

EL-RAHEB, M.; WAGNER, P.

2002-02-01

Transmission of sound across 2-D truss-like periodic double panels separated by an air gap and in contact with an acoustic fluid on the external faces is analyzed. Each panel is made of repeated cells. Combining the transfer matrices of the unit cell forms a set of equations for the overall elastic frequency response. The acoustic pressure in the fluids is expressed using a source boundary element method. Adding rigid reflecting end caps confines the air in the gap between panels which influences sound transmission. Measured values of transmission loss differ from the 2-D model by the wide low-frequency dip of the mass-spring-mass or “msm” resonance also termed the “air gap resonance”. In this case, the panels act as rigid masses and the air gap acts as an adiabatic air spring. Results from the idealized 3-D and 2-D models, incorporating rigid cavities and elastic plates, reveal that the “msm” dip is absent in 2-D models radiating into a semi-infinite medium. The dip strengthens as aspect ratio approaches unity. Even when the dip disappears in 2-D, TL rises more steeply for frequencies above the “msm” frequency.

Cold Atmospheric Plasma (CAP) Changes Gene Expression of Key Molecules of the Wound Healing Machinery and Improves Wound Healing In Vitro and In Vivo

PubMed Central

Arndt, Stephanie; Unger, Petra; Wacker, Eva; Shimizu, Tetsuji; Heinlin, Julia; Li, Yang-Fang; Thomas, Hubertus M.; Morfill, Gregor E.; Zimmermann, Julia L.

2013-01-01

Cold atmospheric plasma (CAP) has the potential to interact with tissue or cells leading to fast, painless and efficient disinfection and furthermore has positive effects on wound healing and tissue regeneration. For clinical implementation it is necessary to examine how CAP improves wound healing and which molecular changes occur after the CAP treatment. In the present study we used the second generation MicroPlaSter ß® in analogy to the current clinical standard (2 min treatment time) in order to determine molecular changes induced by CAP using in vitro cell culture studies with human fibroblasts and an in vivo mouse skin wound healing model. Our in vitro analysis revealed that the CAP treatment induces the expression of important key genes crucial for the wound healing response like IL-6, IL-8, MCP-1, TGF-ß1, TGF-ß2, and promotes the production of collagen type I and alpha-SMA. Scratch wound healing assays showed improved cell migration, whereas cell proliferation analyzed by XTT method, and the apoptotic machinery analyzed by protein array technology, was not altered by CAP in dermal fibroblasts. An in vivo wound healing model confirmed that the CAP treatment affects above mentioned genes involved in wound healing, tissue injury and repair. Additionally, we observed that the CAP treatment improves wound healing in mice, no relevant side effects were detected. We suggest that improved wound healing might be due to the activation of a specified panel of cytokines and growth factors by CAP. In summary, our in vitro human and in vivo animal data suggest that the 2 min treatment with the MicroPlaSter ß® is an effective technique for activating wound healing relevant molecules in dermal fibroblasts leading to improved wound healing, whereas the mechanisms which contribute to these observed effects have to be further investigated. PMID:24265766

Time-resolved spectroscopy of dye-labeled photoactive yellow protein suggests a pathway of light-induced structural changes in the N-terminal cap.

PubMed

Hoersch, Daniel; Otto, Harald; Cusanovich, Michael A; Heyn, Maarten P

2009-07-14

The photoreceptor PYP responds to light activation with global conformational changes. These changes are mainly located in the N-terminal cap of the protein, which is approximately 20 A away from the chromophore binding pocket and separated from it by the central beta-sheet. The question of the propagation of the structural change across the central beta-sheet is of general interest for the superfamily of PAS domain proteins, for which PYP is the structural prototype. Here we measured the kinetics of the structural changes in the N-terminal cap by transient absorption spectroscopy on the ns to second timescale. For this purpose the cysteine mutants A5C and N13C were prepared and labeled with thiol reactive 5-iodoacetamidofluorescein (IAF). A5 is located close to the N-terminus, while N13 is part of helix alpha1 near the functionally important salt bridge E12-K110 between the N-terminal cap and the central anti-parallel beta-sheet. The absorption spectrum of the dye is sensitive to its environment, and serves as a sensor for conformational changes near the labeling site. In both labeled mutants light activation results in a transient red-shift of the fluorescein absorption spectrum. To correlate the conformational changes with the photocycle intermediates of the protein, we compared the kinetics of the transient absorption signal of the dye with that of the p-hydroxycinnamoyl chromophore. While the structural change near A5 is synchronized with the rise of the I(2) intermediate, which is formed in approximately 200 mus, the change near N13 is delayed and rises with the next intermediate I(2)', which forms in approximately 2 ms. This indicates that different parts of the N-terminal cap respond to light activation with different kinetics. For the signaling pathway of photoactive yellow protein we propose a model in which the structural signal propagates from the chromophore binding pocket across the central beta-sheet via the N-terminal region to helix alpha1, resulting in a large change in the protein conformation.

Block Copolymer Adhesion Measured by Contact Mechanics Methods

NASA Astrophysics Data System (ADS)

Falsafi, A.; Bates, S.; Tirrell, M.; Pocius, A. V.

1997-03-01

Adhesion measurements for a series of polyolefin diblocks and triblocks are presented. These materials have poly(ethylene-propylene) or poly(ethyl-ethylene) rubbery block, and semicrystalline polyethylene block as physical crosslinker. The experiments consist of compression and decompression profiles of contact area between the samples as a function of normal load, analyzed by the JKR Theory. The samples are prepared either by formation of caps from the bulk material in melting and subsequent cooling, and/or coating them in thin films on surface modified elastic foundations of polydimethylsiloxane caps. The latter minimizes the viscoelastic losses which are dominant in the bulk of material. The effect of molecular architecture and microstructure on adhesion energy and dynamics of separation, obtained from decompression experiments, is discussed in view of their influence on molecular arrangements at the contacting surfaces.

[Studies on the chemical constitutens of Vicia amoena Fisch].

PubMed

Wei, F; Yan, W M

1997-10-01

One new flavonoide was isolated from Vicia amoena Fisch. On the basis of spectral (UV, MS, NMR) and chemical reactions, it was elucidated to be kaempferol-3-O-beta-D-mannoside, named amoenin(A3). Moreover, five known compounds have been isolated and identified as quercetin, kaempferol, quercetin-3-O-alpha-L-rhamoside, quercetin-3-O-beta-D-glucoside, kaempferol-3, 7-O-alpha-L-dirhamoside. The total flavonoides showed significant effects on inducing hyperlipidemia and increasing micro-blood vessel elasticity.

L-selectin-carbohydrate interactions: relevant modifications of the Lewis x trisaccharide.

PubMed

Sanders, W J; Katsumoto, T R; Bertozzi, C R; Rosen, S D; Kiessling, L L

1996-11-26

Protein-carbohydrate interactions are known to mediate cell-cell recognition and adhesion events. Specifically, three carbohydrate binding proteins termed selectins (E-, P-, and L-selectin) have been shown to be essential for leukocyte rolling along the vascular endothelium, the first step in the recruitment of leukocytes from the blood into inflammatory sites or into secondary lymphoid organs. Although this phenomenon is well-established, little is known about the molecular-level interactions on which it depends. All three selectins recognize sulfated and sialylated derivatives of the Lewis x [Le(x):Gal beta 1-->4(Fuc alpha 1-->3)GlcNAc] and Lewis a [Le(a): Gal beta 1-->3(Fuc alpha 1-->4)GlcNAc] trisaccharide cores with affinities in the millimolar range, and it is believed that variants of these structures are the carbohydrate determinants of selectin recognition. Recently it was shown that the mucin GlyCAM-1, a secreted physiological ligand for L-selectin, is capped with sulfated derivatives of sialyl Lewis x [sLe(x): Sia alpha 2-->3Gal beta 1-->4(Fuc alpha 1-->3)GlcNAc] and that sulfation is required for the high-affinity interaction between GlyCAM-1 and L-selectin. To elucidate the important sites of sulfation on Le(x) with respect to L-selectin recognition, we have synthesized six sulfated Le(x) analogs and determined their abilities to block binding of a recombinant L-selectin-Ig chimera to immobilized GlyCAM-1. Our results suggest that 6-sulfo sLe(x) binds to L-selectin with higher affinity than does sLe(x) or 6'-sulfo sLe(x) and that sulfation of sLe(x) capping groups on GlyCAM-1 at the 6-position is important for L-selectin recognition.

Mo(CO)/sub 6/-promoted reductive cleavage of the carbon-sulfur bond

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

Luh, T.Y.; Wong, C.S.

1985-12-13

In order to study the reductive cleavage of carbon-sulfur bonds by Mo(CO/sub 6/, various organosulfur compounds are reacted with Mo(CO)/sub 6/ in THF. Results of these experiments demonstrate that benzylic-, aryl-, or ..cap alpha..-acyl-activated carbon-sulfur bonds are reduced by treatment with Mo(CO)/sub 6/. 1 table.

Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

PubMed

Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

2016-11-01

Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016. © 2015 Wiley Periodicals, Inc.

In situ chemical analyses of extraterrestrial bodies

NASA Technical Reports Server (NTRS)

Economou, Thanasis E.; Turkevich, Anthony L.

1988-01-01

One of the most important tasks on any sample return mission will have to be a quick sample characterization in order to guarantee a variety of collected samples. An alpha particle instrument with alpha, proton and X-ray modes can provide a quick and almost complete chemical analysis of Mars samples. This instrument is based on three interactions of the alpha particles from a radioactive source with matter: elastic scattering of the alpha particles by nuclei (alpha mode), (alpha,p) nuclear reaction with some light elements (proton mode), and excitation of the atomic structure of atoms by alpha particles, leading to emission of characteristic X-rays of the lunar surface at three sites during the Surveyor mission of 1967 to 1968. Since then the instrument has been improved and miniaturized substantially. As shown in the past, the alpha particle instrument can operate under Martian conditions without any degradation in the performance. The alpha and proton modes can provide vital information about the light elements, while the X-ray mode with its ambient temperature X-ray detector will be useful for the heavier elements. The excitation of the atomic structure is provided by the same alpha radioactive source that is used by alpha and proton modes or by an auxiliary X-ray source that is selected to enhance the sensitivity to some important geochemical elements.

FEM simulation of the die compaction of pharmaceutical products: influence of visco-elastic phenomena and comparison with experiments.

PubMed

Diarra, Harona; Mazel, Vincent; Busignies, Virginie; Tchoreloff, Pierre

2013-09-10

This work studies the influence of visco-elastic behavior in the finite element method (FEM) modeling of die compaction of pharmaceutical products and how such a visco-elastic behavior may improve the agreement between experimental and simulated compression curves. The modeling of the process was conducted on a pharmaceutical excipient, microcrystalline cellulose (MCC), by using Drucker-Prager cap model coupled with creep behavior in Abaqus(®) software. The experimental data were obtained on a compaction simulator (STYLCAM 200R). The elastic deformation of the press was determined by performing experimental tests on a calibration disk and was introduced in the simulation. Numerical optimization was performed to characterize creep parameters. The use of creep behavior in the simulations clearly improved the agreement between the numerical and experimental compression curves (stresses, thickness), mainly during the unloading part of the compaction cycle. For the first time, it was possible to reproduce numerically the fact that the minimum tablet thickness is not obtained at the maximum compression stress. This study proves that creep behavior must be taken into account when modeling the compaction of pharmaceutical products using FEM methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Generation of wavy structure on lipid membrane by peripheral proteins: a linear elastic analysis.

PubMed

Mahata, Paritosh; Das, Sovan Lal

2017-05-01

We carry out a linear elastic analysis to study wavy structure generation on lipid membrane by peripheral membrane proteins. We model the lipid membrane as linearly elastic and anisotropic material. The hydrophobic insertion by proteins into the lipid membrane has been idealized as penetration of rigid rod-like inclusions into the membrane and the electrostatic interaction between protein and membrane has been modeled by a distributed surface traction acting on the membrane surface. With the proposed model we study curvature generation by several binding domains of peripheral membrane proteins containing BAR domains and amphipathic alpha-helices. It is observed that electrostatic interaction is essential for curvature generation by the BAR domains. © 2017 Federation of European Biochemical Societies.

Inhibition of ribosome recruitment induces stress granule formation independently of eukaryotic initiation factor 2alpha phosphorylation.

PubMed

Mazroui, Rachid; Sukarieh, Rami; Bordeleau, Marie-Eve; Kaufman, Randal J; Northcote, Peter; Tanaka, Junichi; Gallouzi, Imed; Pelletier, Jerry

2006-10-01

Cytoplasmic aggregates known as stress granules (SGs) arise as a consequence of cellular stress and contain stalled translation preinitiation complexes. These foci are thought to serve as sites of mRNA storage or triage during the cell stress response. SG formation has been shown to require induction of eukaryotic initiation factor (eIF)2alpha phosphorylation. Herein, we investigate the potential role of other initiation factors in this process and demonstrate that interfering with eIF4A activity, an RNA helicase required for the ribosome recruitment phase of translation initiation, induces SG formation and that this event is not dependent on eIF2alpha phosphorylation. We also show that inhibition of eIF4A activity does not impair the ability of eIF2alpha to be phosphorylated under stress conditions. Furthermore, we observed SG assembly upon inhibition of cap-dependent translation after poliovirus infection. We propose that SG modeling can occur via both eIF2alpha phosphorylation-dependent and -independent pathways that target translation initiation.

Studies of morphological instability and defect formation in heteroepitaxial Si(1-x)Ge(x) thin films via controlled annealing experiments

NASA Astrophysics Data System (ADS)

Ozkan, Cengiz Sinan

Strained layer semiconductor structures provide possibilities for novel electronic devices. When a semiconductor layer is deposited epitaxially onto a single crystal substrate with the same structure but a slightly different lattice parameter, the semiconductor layer grows commensurately with a misfit strain that can be accommodated elastically below a critical thickness. When the critical thickness is exceeded, the elastic strain energy builds up to a point where it becomes energetically favorable to form misfit dislocations. In addition, in the absence of a capping layer, Sisb{1-x}Gesb{x} films exhibit surface roughening via surface diffusion under the effect of a compressive stress which is caused by a lattice mismatch. Surface roughening takes place in the form of ridges aligned along {<}100{>} or {<}110{>} directions depending on the film thickness and the rate of strain relief. Recent work has shown that surface roughening makes a very significant contribution to strain relaxation in heteroepitaxial thin films. At sharp valley regions on the surface, amplified local stresses can cause further defect nucleation and propagation, such as stacking faults and 90sp° dislocations. In addition, capping layers with suitable thickness will surpress surface roughening and keep most of the strain in the film. We study surface roughening and defect formation by conducting controlled annealing experiments on initially flat and defect free films grown by LPCVD in a hydrogen ambient. We study films with both subcritical and supercritical thicknesses. In addition, we compare the relaxation behaviour of capped and uncapped films where surface roughening was inhibited in films with a capping layer. TEM and AFM studies were conducted to study the morphology and microstructure of these films. X-ray diffraction measurements were made to determine the amount of strain relaxation in these films. Further studies of surface roughening on heteroepitaxial films under a positive biaxial stress have shown that, morphological evolution occurs regardless of the sign of stress in the film. Finally, we have studied surface roughening processes in real time by conducting in-situ TEM experiments. We have observed that the kinetics of roughening depend strongly on the annealing ambient.

Endothelial, cardiac muscle and skeletal muscle exhibit different viscous and elastic properties as determined by atomic force microscopy

NASA Technical Reports Server (NTRS)

Mathur, A. B.; Collinsworth, A. M.; Reichert, W. M.; Kraus, W. E.; Truskey, G. A.

2001-01-01

This study evaluated the hypothesis that, due to functional and structural differences, the apparent elastic modulus and viscous behavior of cardiac and skeletal muscle and vascular endothelium would differ. To accurately determine the elastic modulus, the contribution of probe velocity, indentation depth, and the assumed shape of the probe were examined. Hysteresis was observed at high indentation velocities arising from viscous effects. Irreversible deformation was not observed for endothelial cells and hysteresis was negligible below 1 microm/s. For skeletal muscle and cardiac muscle cells, hysteresis was negligible below 0.25 microm/s. Viscous dissipation for endothelial and cardiac muscle cells was higher than for skeletal muscle cells. The calculated elastic modulus was most sensitive to the assumed probe geometry for the first 60 nm of indentation for the three cell types. Modeling the probe as a blunt cone-spherical cap resulted in variation in elastic modulus with indentation depth that was less than that calculated by treating the probe as a conical tip. Substrate contributions were negligible since the elastic modulus reached a steady value for indentations above 60 nm and the probe never indented more than 10% of the cell thickness. Cardiac cells were the stiffest (100.3+/-10.7 kPa), the skeletal muscle cells were intermediate (24.7+/-3.5 kPa), and the endothelial cells were the softest with a range of elastic moduli (1.4+/-0.1 to 6.8+/-0.4 kPa) depending on the location of the cell surface tested. Cardiac and skeletal muscle exhibited nonlinear elastic behavior. These passive mechanical properties are generally consistent with the function of these different cell types.

Suppression of the chain nuclear fusion reaction based on the p+{sup 11}B reaction because of the deceleration of alpha particles

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

Shmatov, M. L., E-mail: M.Shmatov@mail.ioffe.ru

2016-09-15

It is shown that a rapid deceleration of alpha particles in matter of electron temperature up to 100 keV leads a strong suppression of the chain nuclear fusion reaction on the basis of the p+{sup 11}B reaction with the reproduction of fast protons in the α+{sup 11}B and n+{sup 10}B reactions. The statement that the chain nuclear fusion reaction based on the p+{sup 11}B reaction with an acceleration of {sup 11}B nuclei because of elastic alpha-particle scattering manifests itself in experiments at the PALS (Prague Asterix Laser System) facility is analyzed.

Soliton excitations and interactions for the three-coupled fourth-order nonlinear Schrödinger equations in the alpha helical proteins

NASA Astrophysics Data System (ADS)

Sun, Wen-Rong; Tian, Bo; Wang, Yu-Feng; Zhen, Hui-Ling

2015-06-01

Three-coupled fourth-order nonlinear Schrödinger equations describe the dynamics of alpha helical proteins with the interspine coupling at the higher order. Through symbolic computation and binary Bell-polynomial approach, bilinear forms and N-soliton solutions for such equations are constructed. Key point lies in the introduction of auxiliary functions in the Bell-polynomial expression. Asymptotic analysis is applied to investigate the elastic interaction between the two solitons: two solitons keep their original amplitudes, energies and velocities invariant after the interaction except for the phase shifts. Soliton amplitudes are related to the energy distributed in the solitons of the three spines. Overtaking interaction, head-on interaction and bound-state solitons of two solitons are given. Bound states of three bright solitons arise when all of them propagate in parallel. Elastic interaction between the bound-state solitons and one bright soliton is shown. Increase of the lattice parameter can lead to the increase of the soliton velocity, that is, the interaction period becomes shorter. The solitons propagating along the neighbouring spines are found to interact elastically. Those solitons, exhibited in this paper, might be viewed as a possible carrier of bio-energy transport in the protein molecules.

Alpha3, a transposable element that promotes host sexual reproduction.

PubMed

Barsoum, Emad; Martinez, Paula; Aström, Stefan U

2010-01-01

Theoretical models predict that selfish DNA elements require host sex to persist in a population. Therefore, a transposon that induces sex would strongly favor its own spread. We demonstrate that a protein homologous to transposases, called alpha3, was essential for mating type switch in Kluyveromyces lactis. Mutational analysis showed that amino acids conserved among transposases were essential for its function. During switching, sequences in the 5' and 3' flanking regions of the alpha3 gene were joined, forming a DNA circle, showing that alpha3 mobilized from the genome. The sequences encompassing the alpha3 gene circle junctions in the mating type alpha (MATalpha) locus were essential for switching from MATalpha to MATa, suggesting that alpha3 mobilization was a coupled event. Switching also required a DNA-binding protein, Mating type switch 1 (Mts1), whose binding sites in MATalpha were important. Expression of Mts1 was repressed in MATa/MATalpha diploids and by nutrients, limiting switching to haploids in low-nutrient conditions. A hairpin-capped DNA double-strand break (DSB) was observed in the MATa locus in mre11 mutant strains, indicating that mating type switch was induced by MAT-specific DSBs. This study provides empirical evidence for selfish DNA promoting host sexual reproduction by mediating mating type switch.

[Cardiovascular effects of prostaglandin F 2 alpha in early pregnancy].

PubMed

Retzke, U; Schwarz, R

1976-01-01

In 10 normotensive healthy early pregnant women cardiovascular studies were done before, during and after the intravenous administration of prostaglandin F2alpha with the method of quantitative sphygmometry. Arterial blood pressure was measured graphically with an automatic sphygmomanometer unit. Velocity of aortic pulse wave was determined directly on the principle of exact electronic timing. Prostaglandin F2alpha was infused with electric pump in the dosage of 6, 5, 13 and 26 mug per minute for 30 minutes in each case. Arterial blood pressure is nearly constant. Heart rate, the elasticity coefficient of the arteries E' and total peripheral resistance decreases significantly. Stroke volume, cardiac output, work and power of the heart increases significantly. Nevertheless there are no contra-indications on the part of cardiovascular system for using prostaglandin F2alpha for induction of abortion

Doppler-broadening measurements of x-ray lines for determination of the ion temperature in tokamak plasmas

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

Bitter, M.; von Goeler, S.; Horton, R.

1979-01-29

Ion-temperature results are deduced from Doppler-broadening measurements of the K..cap alpha.. (1s-2p) resonance line emitted from heliumlike iron impurity ions in the hot central core of PLT (Princeton Large Torus) tokamak discharges. The measurements were performed using a high-resolution Bragg-crystal spectrometer with a multiwire proportional counter.

Structural phase transitions in GaAs to 108 GPa

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

Weir, S.T.; Vohra, Y.K.; Vanderborgh, C.A.

1989-01-15

The III-V compound GaAs was studied using energy-dispersive x-ray diffraction with a synchro- tron source up to a pressure of 108 GPa. When the pressure was increased to 16.6 GPa, the GaAs sample transformed from the zinc-blende structure to an orthorhombic structure (GaAs(II)), space group Pmm2, consisting of a primitive orthorhombic lattice with a basis of (0,0,0) and (0,(1/2,..cap alpha..), where ..cap alpha.. = 0.35. Upon a further increase of pressure to 24 +- 1 GPa, GaAs(II) transformed to another orthorhombic structure (GaAs(III)), space group Imm2, consisting of a body-centered orthorhombic lattice with a basis of (0,0,0) and (0, (1/2,..delta..),more » where ..delta.. is 0.425 at 28.1 GPa. With increasing pressure, ..delta.. approached (1/2 and the GaAs(III) structure gradually assumed the symmetry of the simple hexagonal structure. The transition to the simple hexagonal structure (GaAs(IV)) was completed in the vicinity of 60--80 GPa. The structure remains simple hexagonal up to at least 108 GPa, the highest pressure reached in this study.« less

Use of antibodies specific to defined regions of scorpion. cap alpha. -toxin to study its interaction with its receptor site on the sodium channel

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

Ayeb, M.E.; Bahraoui, E.M.; Granier, C.

1986-10-21

Five antibody populations selected by immunoaffinity chromatography for the specificity toward various regions of toxin II of the scorpion Androctonus australis Hector were used to probe the interaction of this protein with its receptor site on the sodium channel. These studies indicate that two antigenic sites, one located around the disulfide bridge 12-63 and one encompassing residues 50-59, are involved in the molecular mechanisms of toxicity neutralization. Fab fragments specific to the region around disulfide bridge 12-63 inhibit binding of the /sup 125/I-labeled toxin to its receptor site. Also, these two antigenic regions are inaccessible to the antibodies when themore » toxin is bound to its receptor site. In contrast, the two other antigenic sites encompassing the only ..cap alpha..-helix region (residues 23-32) and a ..beta..-turn structure (residues 32-35) are accessible to the respective antibodies when the toxin is bound to its receptor. Together, these data support the recent proposal that a region made of residues that are conserved in the scorpion toxin family is involved in the binding of the toxin to the receptor.« less

Survey of the (. cap alpha. ,/sup 2/He) reaction on 1p- and 2s1d-shell nuclei

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

Jahn, R.; Stahel, D.P.; Wozniak, G.J.

A /sup 2/He detection system has been developed and used to investigate the (..cap alpha..,/sup 2/He) reaction at bombarding energies of 55 and 65 MeV on targets of /sup 12/C, /sup 13/C, /sup 14/N, /sup 15/N, /sup 16/O, /sup 18/O, /sup 20/Ne, /sup 22/Ne, /sup 24/Mg, /sup 26/Mg, /sup 28/Si, /sup 29/Si, /sup 32/S, /sup 36/Ar, /sup 38/Ar, and /sup 40/Ca. Preferential population of two-neutron states with dominant (d/sub 5/2/)/sup 2//sub 4/, (d/sub 3/2/f/sub 7/2/)/sub 5/, and (f/sub 7/2/)/sup 2//sub 6/ character was observed. A linear A dependence of the binding energies of the J/sup ..pi../ = 5/sup -/ andmore » 6/sup +/ states was obtained. This systematic behavior is well described by the Bansal-French model, using the parameters a = - 0.30 MeV and b = 2.6 MeV. Simple shell-model calculations for the 2n configurations are in good agreement with the experimental data.« less

Multiconfiguration resonating-group theory of the seven-nucleon system with realistic cluster wave functions

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

Fujiwara, Y.; Tang, Y.C.

1985-02-01

The properties of the seven-nucleon system are examined with a multiconfiguration and multi- channel resonating-group calculation. The cluster internal functions employed explain the charge-form-factor data over a wide range of q/sup 2/ and satisfy the variational stability condition quite well. The model space used is spanned by /sup 3/H+..cap alpha.., n+ /sup 6/Li, n+ /sup 6/Li(, and d+ /sup 5/He cluster configurations. The result shows that the specific distortion of the /sup 3/H+..cap alpha.. system is quite significant. With our multiconfiguration calculation, the ground-state energy is improved by more than 1 MeV. The calculated level spectrum agrees well with themore » level spectrum empirically determined. The energy positions of both natural-parity and unnatural-parity levels are reasonably explained. In addition, we find that, because of centrifugal-barrier effects, the aligned configuration generally makes the most sig- nificant contribution. The characteristics of nucleon-exchange terms are also briefly examined. Here it is found that, at sufficiently high energies where sharp resonance levels do not exist, the essential properties of these terms can already be learned by performing relatively simple single-configuration calculations.« less

Effects of capsaicin in the motor nerve.

PubMed

Pettorossi, V E; Bortolami, R; Della Torre, G; Brunetti, O

1994-08-01

The injection of capsaicin into the lateral gastrocnemius (LG) muscle of the rat induced an immediate and sustained reduction in the A delta and C components of the compound action potential (CAP) of the LG motor nerve. Conversely, the drug did not immediately affect the CAP wave belonging to fast-conducting fibers or the motor responses to LG nerve stimulation. It seems that capsaicin only affects the group III and IV afferents of LG nerve. However, a week after the injection the capsaicin also altered the motor responses, as shown by the threshold enhancement and amplitude reduction of the muscle twitch and by the decrease of the A alpha-beta CAP components. This late motor impairment was attributed to a central depression following a reduction of capsaicin-sensitive neuron input into the CNS. However, this motor effect was transient since the LG nerve regained the preinjection excitability level in a week and the muscle twitch amplitude reached the control value in a month.

Preparation and characterization of highly water-soluble magnetic Fe3O4 nanoparticles via surface double-layered self-assembly method of sodium alpha-olefin sulfonate

NASA Astrophysics Data System (ADS)

Li, Honghong; Qin, Li; Feng, Ying; Hu, Lihua; Zhou, Chunhua

2015-06-01

A kind of double-layered self-assembly sodium alpha-olefin sulfonate (AOS) capped Fe3O4 magnetic nanoparticles (Fe3O4-AOS-MN) with highly water-solubility was prepared by a wet co-precipitation method with a pH of 4.8. The resulting Fe3O4-AOS-MN could be dispersed into water to form stable magnetic fluid without other treatments. The result of X-ray diffraction (XRD) indicated that the Fe3O4-AOS-MN maintained original crystalline structure and exhibited a diameter of about 7.5 nm. The iron oxide phase of nanoparticles determined by Raman spectroscopy is Fe3O4. Transmission electron microscopy (TEM) analysis confirmed that the Fe3O4-AOS-MN with spherical morphology were uniformly dispersed in water. FT-IR spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) verified the successful preparation of Fe3O4-AOS-MN capped with double-layered self-assembled AOS. The corresponding capacities of monolayer chemical absorption and the second-layer self-assembly absorption were respectively 4.07 and 14.71 wt% of Fe3O4-MN, which were much lower than those of other surfactants. Vibrating sample magnetometer (VSM) test result showed Fe3O4-AOS-MN possessed superparamagnetic behavior with the saturation magnetization value of about 44.45 emu/g. The blocking temperature TB of Fe3O4-AOS-MN capped with double-layered AOS is 170 K.

Direct assays of radiation-induced DNA base lesions in mammalian cells: Technical progress report, July 1, 1986--December 1, 1988

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

Wheeler, K.T. Jr.

1988-01-01

Our cesium irradiator was installed in April 1987 and has the capability of irradiating DNA solutions, cells and animals at dose rates from >60 Gy/min to <10/sup /minus/2/ Gy/min. By early summer all of the dosimetry and set-ups were established to perform this research. In may 1987, Dr. Krystyna Lesiak left to return to the National Institutes of Health. However, she has remained a collaborator over the past 1/1/2/ years. She has synthesized a large lot of ..cap alpha..-deoxyadenosine, isolated a large batch of both the R and S isomer of cyclodeoxyadenosine and has capped the ..cap alpha..-deoxyadenonsine for usemore » in a DNA synthesizer that uses phosphoramidite chemistry. In November 1987, Dr. Andrzej Surowiec joined our unit as a Visiting Research Assistant Professor. Dr. Surowiec has a MS degree in electrical engineering and did his Ph.D. in Biophysics studying the conductivity of DNA in dilute solution. He has been performing the helix-coil transition experiments. In November 1987, Dr. Steven Swarts also joined our unit as a Postdoctoral Fellow. He received his Ph.D. from Oakland University under Dr. Michael Sevilla with whom we have a collaboration studying the induction of base damage in hydrated DNA. Dr. Swarts has a strong background in spectroscopy and, therefore, was a key individual for determination of the limitations of the HPLC assays and the establishment of a GC/MS capability equivalent to Dr. M. Dizdaroglu at the National Bureau of Standards. 9 refs., 1 tab.« less

Hydrothermal synthesis of alpha- and beta-HgS nanostructures

NASA Astrophysics Data System (ADS)

Galain, Isabel; María, Pérez Barthaburu; Ivana, Aguiar; Laura, Fornaro

2017-01-01

We synthesized HgS nanostructures by the hydrothermal method in order to use them as electron acceptors in hybrid organic-inorganic solar cells. We employed different mercury sources (HgO and Hg(CH3COO)2) and polyvinylpyrrolidone (PVP) or hexadecanethiol (HDT) as stabilizing/capping agent for controlling size, crystallinity, morphology and stability of the obtained nanostructures. We also used thiourea as sulfur source, and a temperature of 180 °C during 6 h. Synthesized nanostructures were characterized by powder X-Ray Diffraction, Diffuse Reflectance Infrared Fourier Transform and Transmission Electron Microscopy. When PVP acts as stabilizing agent, the mercury source has influence on the size -but not in morphology- of the beta-HgS obtained nansostructures. HDT has control over nanostructures' size and depending on the relation Hg:HDT, we obtained a mixture of alpha and beta HgS which can be advantageous in the application in solar cells, due their absorption in different spectral regions. The smallest nanostructures obtained have a mean diameter of 20 nm when using HDT as capping agent. Also, we deposited the aforementioned nanostructures onto flat glass substrates by the spin coating technique as a first approach of an active layer of a solar cell. The depositions were characterized by atomic force microscopy. We obtained smaller particle deposition and higher particle density -but a lower area coverage (5%) - in samples with HDT as capping agent. This work presents promising results on nanostructures for future application on hybrid solar cells. Further efforts will be focused on the deposition of organic-inorganic layers.

Angular momentum dependence in 22 MeV $alpha$-particle elastic scattering by light nuclei

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

Lega, J.; Macq, P.C.

1974-01-01

Elastic scattering of 22 MeV alpha -particles by /sup 23, /sup 24,15,26/ Mg, /sup 27/Al and /sup 28/Si was measured between 24 and 174 deg lab. Partial angular distributions, from 120 to 174 deg , were also measured at incident energies of 18.4 and 20.7 MeV for /sup 24/Mg, and 18.9 and 20.5 MeV for /sup 28/ Si. The most striking feature of the data is the large-angle behavior spin-zero nuclei display more pronounced backward oscillations and the cross section rises more steeply towards 180 deg for 4n nuclei than for the others. Optical Model analyses with an l-dependent absorptionmore » and a minimum of free parameters are used to describe the general trend of the data for A = 23 to 28 nuclei at different energies; a spinorbit coupling term, 2.75 MeV deep, is added to describe the /sup 23/Na scattering data. (auth)« less

Treatment of catastrophic antiphospholipid syndrome with defibrotide, a proposed vascular endothelial cell modulator.

PubMed

Burcoglu-O'Ral, Arsinur; Erkan, Doruk; Asherson, Ronald

2002-09-01

To define at the molecular level the vascular endothelial cell (VEC) injury characteristics of catastrophic antiphospholipid syndrome (CAPS) and to report successful therapeutic use of a VEC modulator, defibrotide. We describe a 55-year-old man with primary APS with an intractable prothrombotic state (CAPS) resistant to combined therapy with heparin, warfarin, aspirin, and dipyridamole. Treatment with defibrotide was conducted in the context of an investigational phase II protocol where the dose was regulated and individualized by disease/patient-specific molecular and clinical markers. The patient entered complete remission with defibrotide treatment. During treatment, dose dependent pharmacological actions of defibrotide and key stress markers for VEC injury were identified. Evidence of defibrotide's polypharmacology included downregulation of cytokines, notably tumor necrosis factor-alpha, as the earliest effect, cellular differentiation of VEC, possibly with direct regulatory effect over cellular genes, and the reversal of platelet consumption and prothrombotic state. Von Willebrand antigen levels were used as the sole marker to guide therapy. This case demonstrates effective remission of CAPS with defibrotide treatment. In contrast to theories that CAPS is triggered by ischemic and thrombotic tissue damage, these data present VEC injury as the primary and representative lesion of CAPS. The pathogenesis may involve concurrent impairment of different VEC functions. Achieving remission may require a polypharmacologic approach, represented here by use of defibrotide.

Characterization of the primary interaction between the mating pheromone, alpha-factor, and its receptor in Saccharomyces cerevisiae

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

Raths, S.K.

1987-01-01

Alpha-factor is a peptide of thirteen amino acids which is required for mating between the haploid mating types, a and ..cap alpha.., in Saccharomyces cerevisiae. An analogue of alpha-factor, DHP/sup 8/ DHP/sup 11/ Nle/sup 12/ tridecapeptide, was catalytically reduced in the presence of /sup 3/H gas for production of a radiolabeled pheromone suitable for use in binding studies. Incorporation of tritium resulted in /sup 3/H-alpha-factor with high specific activity, purity, biological activity and long shelf-life. Binding studies revealed that alpha-factor interacts with its receptor via a simple, reversible process which obeys the law of mass action. Association and dissociation kineticsmore » indicate values of 2.92 x 10/sup 6/ M/sup /minus/1/ min/sup -1/ for k/sub 1/ and between 4 and 7 x 10/sup /minus/2/ min/sup /minus/1/ for k/sub /minus/1/. Saturation binding studies reveal an equilibrium dissociation constant equal to 2.32 x 10/sup /minus/8/ M which approximate the kinetically-derived K/sub D/ of 2.12 x 10/sup /minus/8/ M. Scatchard and Hill analyses as well as dissociation behavior in the presence of excess unlabeled ligand indicate alpha-factor interacts with a homogeneous population of binding sites which do not interact and exhibit one affinity for the alpha-factor pheromone.« less

Application of viscoelastic, viscoplastic, and rate-and-state friction constitutive laws to the deformation of unconsolidated sands

NASA Astrophysics Data System (ADS)

Hagin, Paul N.

Laboratory experiments on dry, unconsolidated sands from the Wilmington field, CA, reveal significant viscous creep strain under a variety of loading conditions. In hydrostatic compression tests between 10 and 50 MPa of pressure, the creep strain exceeds the magnitude of the instantaneous strain and follows a power law function of time. Interestingly, the viscous effects only appear when loading a sample beyond its preconsolidation pressure. Cyclic loading tests (at quasi-static frequencies of 10-6 to 10 -2 Hz) show that the bulk modulus increases by a factor of two with increasing frequency while attenuation remains constant. I attempt to fit these observations using three classes of models: linear viscoelastic, viscoplastic, and rate-and-state friction models. For the linear viscoelastic modeling, I investigated two types of models; spring-dashpot (exponential) and power law models. I find that a combined power law-Maxwell solid creep model adequately fits all of the data. Extrapolating the power law-Maxwell creep model out to 30 years (to simulate the lifetime of a reservoir) predicts that the static bulk modulus is 25% of the dynamic modulus, in good agreement with field observations. Laboratory studies also reveal that a large portion of the deformation is permanent, suggesting that an elastic-plastic model is appropriate. However, because the viscous component of deformation is significant, an elastic-viscoplastic model is necessary. An appropriate model for unconsolidated sands is developed by incorporating Perzyna (power law) viscoplasticity theory into the modified Cambridge clay cap model. Hydrostatic compression tests conducted as a function of volumetric strain rate produced values for the required model parameters. As a result, by using an end cap model combined with power law viscoplasticity theory, changes in porosity in both the elastic and viscoplastic regimes can be predicted as a function of both stress path and strain rate. To test whether rate-and-state friction laws can be used to model creep strain, I expand the rate-and-state formulation to include deformation under hydrostatic stress boundary conditions. Results show that the expanded rate-and-state formulation successfully describes the creep strain of unconsolidated sand. Finally, I show that the viscoplastic end cap and rate-and-state models are mathematically similar.

A new genetic factor for root gravitropism in rice (Oryza sativa L.).

PubMed

Shi, Jiang-hua; Hao, Xi; Wu, Zhong-chang; Wu, Ping

2009-10-01

Root gravitropism is one of the important factors to determine root architecture. To understand the mechanism underlying root gravitropism, we isolated a rice (Xiushui63) mutant defective in root gravitropism, designated as gls1. Vertical sections of root caps revealed that gls1 mutant displayed normal distribution of amyloplast in the columella cells compared with the wild type. The gls1 mutant was less sensitive to 2,4-dichlorophenoxyacetic acid (2,4-D) and alpha-naphthaleneacetic acid (NAA) than the wild type. Genetic analysis indicated that the phenotype of gls1 mutant was caused by a single recessive mutation, which is mapped in a 255-kb region between RM16253 and CAPS1 on the short arm of chromosome 4.

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals.

PubMed

Martynyuk-Lototska, Irina; Mys, Oksana; Dudok, Taras; Adamiv, Volodymyr; Smirnov, Yevgen; Vlokh, Rostyslav

2008-07-01

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.

Hipergeometric solutions to some nonhomogeneous equations of fractional order

NASA Astrophysics Data System (ADS)

Olivares, Jorge; Martin, Pablo; Maass, Fernando

2017-12-01

In this paper a study is performed to the solution of the linear non homogeneous fractional order alpha differential equation equal to I 0(x), where I 0(x) is the modified Bessel function of order zero, the initial condition is f(0)=0 and 0 < alpha < 1. Caputo definition for the fractional derivatives is considered. Fractional derivatives have become important in physical and chemical phenomena as visco-elasticity and visco-plasticity, anomalous diffusion and electric circuits. In particular in this work the values of alpha=1/2, 1/4 and 3/4. are explicitly considered . In these cases Laplace transform is applied, and later the inverse Laplace transform leads to the solutions of the differential equation, which become hypergeometric functions.

Elastic Scattering of {sup 7}Li+{sup 27}Al at Backward Angles in the 7-11 MeV Energy Range for Application in RBS

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

Carnelli, P. F. F.; Arazi, A.; Cardona, M. A.

2010-08-04

We have measured elastic excitation functions for the {sup 7}Li+{sup 27}Al system, in an energy range close to its Coulomb barrier (E{sub lab} = 8.4 MeV) in steps of 0.25 MeV. For this purpose, an array of eight surface-barrier detectors was used. To get an insight on the background composition (mainly {alpha} particles), a telescope-detector was used for atomic-number identification. Identical measurements for the {sup 6}Li+{sup 27}Al system are planned for the near future.

Elastic alpha-particle resonances as evidence of clustering at high excitation in 40Ca

NASA Astrophysics Data System (ADS)

Norrby, M.; Lönnroth, T.; Goldberg, V. Z.; Rogachev, G. V.; Golovkov, M. S.; Källman, K.-M.; Lattuada, M.; Perov, S. V.; Romano, S.; Skorodumov, B. B.; Tiourin, G. P.; Trzaska, W. H.; Tumino, A.; Vorontsov, A. N.

2011-08-01

The elastic-scattering reaction 36Ar + α was studied using the Thick Target Inverse Kinematics technique. Data were taken at a beam energy of 150 MeV in a reaction chamber filled with 4He gas, corresponding to the excitation region of 12-20 MeV in 40Ca. Using a simplified R -matrix method of analysis energies, widths and spin assignments were obtained for 137 resonances. The structure is discussed within the concept of α-cluster structure in the quasi-continuum of 40Ca and is compared to other nuclei in the same mass region.

Polariton effects in naphthalene crystals

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

Robinette, Susan Louise

1977-10-01

The experimental verification of the two-step nature of energy dissipation of photon energy by a crystal is the subject of this dissertation. The ..cap alpha..(O,O) Davydov component of the lowest energy singlet transition in pure strain-free napthalene single crystals is shown to exhibit an increase in absorption with increasing temperature, due to an increase in polariton damping via polariton-phonon scattering processes. (GHT)

EFFECT OF POLONIUM /cap alpha/ RADIATION ON GELATINE (in French)

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

Ader, M.

1962-08-01

When a nuclear plate, which has been exposed to radiation, developed, and dried, is exposed to a Po source, no effect can be detected by either the eye or the microscope. However if the plate is placed in distilled water, the emulsion thickness of the irradiated region is reduced by approximately 20 mu . A ridge'' separates this region from the nonirradiated region. The ridge contains piles of silver grains, very deformed traces of the old radiation, and some gelatin fragments. It appears that the alpha particles penetrating the gelatine transforms this gelatin, reversible protein, into a substance soluble'' inmore » distilled water or entrained by the distilled water. (J.S.R.)« less

[Expression and distribution of xenoantigen alpha-Gal in intervertebral disk of Chinese banna minipig inbred line].

PubMed

Shou, Jian-guo; Mi, Jian-hong; Ying, Da-jun

2002-09-01

To investigate the expression and distribution of xenoantigen in intervertebral disk of Chinese banna minipig inbred line, and to study the availability of xenograft transplantation of intervertebral disk. Samples of intervertebral disk were collected from six Banna pigs of 8 to 11-month-old. The fixation, embedment and slice were performed. alpha-Gal specific binding lection (BSI-B4) were used as affinity reagents and affinity-immunohistochemistry assays (SABC methods and DAB stain) were conducted to detect the expression and distribution of xenoantigen (alpha-Gal). alpha-Gal was found in chondrocyte cell and chondrocyte-like cell in intervertebral disk which have the positive yellow-stained particulate aggradation. There was no stain in the matrix, elastic fiber and collagen fiber. The distribution of xenoantigen is locally in the tissue of intervertebral disk and its expression is weak. This suggests that the intervertebral disk of Banna pig may be alternative donor for xenotransplantation.

Assessment of Multiaxial Mechanical Response of Rigid Polyurethane Foams

NASA Astrophysics Data System (ADS)

Pettarin, Valeria; Fasce, Laura A.; Frontini, Patricia M.

2014-02-01

Multiaxial deformation behavior and failure surface of rigid polyurethane foams were determined using standard experimental facilities. Two commercial foams of different densities were assayed under uniaxial, biaxial, and triaxial stress states. These different stress states were reached in a uniaxial universal testing machine using suitable testing configurations which imply the use of special grips and lateral restricted samples. Actual strains were monitored with a video extensometer. Polyurethane foams exhibited typical isotropic brittle behavior, except under compressive loads where the response turned out to be ductile. A general failure surface in the stress space which accounts for density effects could be successfully generated. All of failure data, determined at the loss of linear elasticity point, collapsed in a single locus defined as the combination of a brittle crushing of closed-cell cellular materials criterion capped by an elastic buckling criterion.

Surfactant-Mediated Growth of Ge/Si(001) Interface Studied by XPD

NASA Astrophysics Data System (ADS)

Gunnella, R.; Castrucci, P.; Pinto, N.; Cucculelli, P.; Davoli, I.; Sébilleau, D.; de Crescenzi, M.

The influence of Sb as a surfactant on the formation of Si/Ge interface is studied by means of XPD (X-ray photoelectron diffraction) and AED (Auger electron diffraction) from Ge and Si core levels. The technique employed is particularly suitable for checking the film tetragonal distortion, the growth morphology and the sharpness of the interface. We found a layer by layer growth mode for 3 ML of Ge on Si(001) and related values of strain of the film close to the value predicted by the elastic theory which enforces the use of such a surfactant to obtain high quality and sharp heterostructures. In addition, studying the influence of 3 ML of the Si cap layer on the 3 ML Ge, we obtain no indication of Ge segregation into the Si cap layer. Finally, evidences of quality degradation after high temperature (T > 600°C) annealing are shown.

Comparison of U.S. Environmental Protection Agency’s CAP88 PC versions 3.0 and 4.0

DOE PAGES

Jannik, Tim; Farfan, Eduardo B.; Dixon, Ken; ...

2015-08-01

The Savannah River National Laboratory (SRNL) with the assistance of Georgia Regents University, completed a comparison of the U.S. Environmental Protection Agency's (EPA) environmental dosimetry code CAP88 PC V3.0 with the recently developed V4.0. CAP88 is a set of computer programs and databases used for estimation of dose and risk from radionuclide emissions to air. At the U.S. Department of Energy's Savannah River Site, CAP88 is used by SRNL for determining compliance with EPA's National Emission Standards for Hazardous Air Pollutants (40 CFR 61, Subpart H) regulations. Using standardized input parameters, individual runs were conducted for each radionuclide within itsmore » corresponding database. Some radioactive decay constants, human usage parameters, and dose coefficients changed between the two versions, directly causing a proportional change in the total effective 137Cs, 3H, 129I, 239Pu, and 90Sr) is provided. In general, the total effective doses will decrease for alpha/beta emitters because of reduced inhalation and ingestion rates in V4.0. However, for gamma emitters, such as 60Co and 137Cs, the total effective doses will increase because of changes EPA made in the external ground shine calculations.« less

An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin

PubMed Central

Tran, Diana; Townley, Joshua P; Barnes, Tanya M; Greive, Kerryn A

2015-01-01

Background The demand for antiaging products has dramatically increased in recent years, driven by an aging population seeking to maintain the appearance of youth. This study investigates the effects of an antiaging skin care system containing alpha hydroxy acids (AHAs) in conjunction with vitamins B3, C, and E on the biomechanical parameters of facial skin. Methods Fifty two volunteers followed an antiaging skin care regimen comprising of cleanser, eye cream, day moisturizer, and night moisturizer for 21 days. Wrinkle depth (Ry) and skin roughness (Ra) were measured by skin surface profilometry of the crow’s feet area, and skin elasticity parameters R2 (gross elasticity), R5 (net elasticity), R6 (viscoelastic portion), and R7 (recovery after deformation) were determined for facial skin by cutometer, preapplication and after 7, 14, and 21 days. Volunteers also completed a self-assessment questionnaire. Results Compared to baseline, Ry and Ra significantly improved by 32.5% (P<0.0001) and 42.9% (P<0.0001), respectively, after 21 days of antiaging skin care treatment. These results were observed by the volunteers with 9 out of 10 discerning an improvement in skin texture and smoothness. Compared to baseline, R2 and R5 significantly increased by 15.2% (P<0.0001) and 12.5% (P=0.0449), respectively, while R6 significantly decreased by 17.7% (P<0.0001) after 21 days. R7 increased by 9.7% after 21 days compared to baseline but this was not significant over this time period. Conclusion An antiaging skin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects. PMID:25552908

Influence of chemistry, interfacial width, and non-isothermal conditions on spatially heterogeneous activated relaxation and elasticity in glass-forming free standing films

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

Mirigian, Stephen; Schweizer, Kenneth S.

Here, we employ the Elastically Collective Nonlinear Langevin Equation (ECNLE) theory of activated relaxation to study several questions in free standing thin films of glass-forming molecular and polymer liquids. The influence of non-universal chemical aspects on dynamical confinement effects is found to be relatively weak, but with the caveat that for the systems examined, the bulk ECNLE polymer theory does not predict widely varying fragilities. Allowing the film model to have a realistic vapor interfacial width significantly enhances the reduction of the film-averaged glass transition temperature, T g, in a manner that depends on whether a dynamic or pseudo-thermodynamic averagingmore » of the spatial mobility gradient is adopted. The nature of film thickness effects on the spatial profiles of the alpha relaxation time and elastic modulus is studied under non-isothermal conditions and contrasted with the corresponding isothermal behavior. Modest differences are found if a film-thickness dependent T g is defined in a dynamical manner. But, adopting a pseudo-thermodynamic measure of T g leads to a qualitatively new form of the alpha relaxation time gradient where highly mobile layers near the film surface coexist with strongly vitrified regions in the film interior. Consequently, the film-averaged shear modulus can increase with decreasing film thickness, despite the T g reduction and presence of a mobile surface layer. Such a behavior stands in qualitative contrast to the predicted mechanical softening under isothermal conditions. Spatial gradients of the elastic modulus are studied as a function of temperature, film thickness, probing frequency, and experimental protocol, and a rich behavior is found.« less

Influence of chemistry, interfacial width, and non-isothermal conditions on spatially heterogeneous activated relaxation and elasticity in glass-forming free standing films

DOE PAGES

Mirigian, Stephen; Schweizer, Kenneth S.

2017-02-02

Here, we employ the Elastically Collective Nonlinear Langevin Equation (ECNLE) theory of activated relaxation to study several questions in free standing thin films of glass-forming molecular and polymer liquids. The influence of non-universal chemical aspects on dynamical confinement effects is found to be relatively weak, but with the caveat that for the systems examined, the bulk ECNLE polymer theory does not predict widely varying fragilities. Allowing the film model to have a realistic vapor interfacial width significantly enhances the reduction of the film-averaged glass transition temperature, T g, in a manner that depends on whether a dynamic or pseudo-thermodynamic averagingmore » of the spatial mobility gradient is adopted. The nature of film thickness effects on the spatial profiles of the alpha relaxation time and elastic modulus is studied under non-isothermal conditions and contrasted with the corresponding isothermal behavior. Modest differences are found if a film-thickness dependent T g is defined in a dynamical manner. But, adopting a pseudo-thermodynamic measure of T g leads to a qualitatively new form of the alpha relaxation time gradient where highly mobile layers near the film surface coexist with strongly vitrified regions in the film interior. Consequently, the film-averaged shear modulus can increase with decreasing film thickness, despite the T g reduction and presence of a mobile surface layer. Such a behavior stands in qualitative contrast to the predicted mechanical softening under isothermal conditions. Spatial gradients of the elastic modulus are studied as a function of temperature, film thickness, probing frequency, and experimental protocol, and a rich behavior is found.« less

An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin.

PubMed

Tran, Diana; Townley, Joshua P; Barnes, Tanya M; Greive, Kerryn A

2015-01-01

The demand for antiaging products has dramatically increased in recent years, driven by an aging population seeking to maintain the appearance of youth. This study investigates the effects of an antiaging skin care system containing alpha hydroxy acids (AHAs) in conjunction with vitamins B3, C, and E on the biomechanical parameters of facial skin. Fifty two volunteers followed an antiaging skin care regimen comprising of cleanser, eye cream, day moisturizer, and night moisturizer for 21 days. Wrinkle depth (Ry ) and skin roughness (Ra ) were measured by skin surface profilometry of the crow's feet area, and skin elasticity parameters R2 (gross elasticity), R5 (net elasticity), R6 (viscoelastic portion), and R7 (recovery after deformation) were determined for facial skin by cutometer, preapplication and after 7, 14, and 21 days. Volunteers also completed a self-assessment questionnaire. Compared to baseline, Ry and Ra significantly improved by 32.5% (P<0.0001) and 42.9% (P<0.0001), respectively, after 21 days of antiaging skin care treatment. These results were observed by the volunteers with 9 out of 10 discerning an improvement in skin texture and smoothness. Compared to baseline, R2 and R5 significantly increased by 15.2% (P<0.0001) and 12.5% (P=0.0449), respectively, while R6 significantly decreased by 17.7% (P<0.0001) after 21 days. R7 increased by 9.7% after 21 days compared to baseline but this was not significant over this time period. An antiaging skin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects.

The uteroglobin fold.

PubMed

Callebaut, I; Poupon, A; Bally, R; Demaret, J P; Housset, D; Delettré, J; Hossenlopp, P; Mornon, J P

2000-01-01

Uteroglobin (UTG) forms a fascinating homodimeric structure that binds small- to medium-sized ligands through an internal hydrophobic cavity, located at the interface between the two monomers. Previous studies have shown that UTG fold is not limited to the UTG/CC10 family, whose sequence/structure relationships are highlighted here, but can be extended to the cap domain of Xanthobacter autotrophicus haloalkane dehalogenase. We show here that UTG fold is adopted by several other cap domains within the alpha/beta hydrolase family, making it a well-suited "geode" structure allowing it to sequester various hydrophobic molecules. Additionally, some data about a new crystal form of oxidized rabbit UTG are presented, completing previous structural studies, as well as results from molecular dynamics, suggesting an alternative way for the ligand to reach the internal cavity.

Refined elasticity sampling for Monte Carlo-based identification of stabilizing network patterns.

PubMed

Childs, Dorothee; Grimbs, Sergio; Selbig, Joachim

2015-06-15

Structural kinetic modelling (SKM) is a framework to analyse whether a metabolic steady state remains stable under perturbation, without requiring detailed knowledge about individual rate equations. It provides a representation of the system's Jacobian matrix that depends solely on the network structure, steady state measurements, and the elasticities at the steady state. For a measured steady state, stability criteria can be derived by generating a large number of SKMs with randomly sampled elasticities and evaluating the resulting Jacobian matrices. The elasticity space can be analysed statistically in order to detect network positions that contribute significantly to the perturbation response. Here, we extend this approach by examining the kinetic feasibility of the elasticity combinations created during Monte Carlo sampling. Using a set of small example systems, we show that the majority of sampled SKMs would yield negative kinetic parameters if they were translated back into kinetic models. To overcome this problem, a simple criterion is formulated that mitigates such infeasible models. After evaluating the small example pathways, the methodology was used to study two steady states of the neuronal TCA cycle and the intrinsic mechanisms responsible for their stability or instability. The findings of the statistical elasticity analysis confirm that several elasticities are jointly coordinated to control stability and that the main source for potential instabilities are mutations in the enzyme alpha-ketoglutarate dehydrogenase. © The Author 2015. Published by Oxford University Press.

Time variations of magnetospheric intensities of outer zone protons, alpha particles and ions (Z greater than or equal to 2). Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Randall, B. A.

1973-01-01

A comprehensive study of the temporal behavior of trapped protons, alpha particles and ions (Z 2) in outer zone of the earth's magnetosphere has been made. These observations were made by the Injun V satellite during the first 21 months of operation, August 1968 to May 1970. Rapid increases in the observed number of particles followed by slower exponential decay characterize the data. Comparisons are made with the temporal behavior of interplanetary particles of the same energy observed by Explorer 35. Increases in the trapped fluxes generally correspond to enhanced interplanetary activity. The energy spectra of protons and alpha particles at L = 3 have similar shapes when compared on an energy per charge basis while the respective polar cap spectra have similar shape on an energy per nucleon basis. Apparent inward trans-L motion of energetic protons is observed. These particles are diffused inward by a process involving fluctuating electric fields. The loss of trapped low altitude protons, alpha particles and ions (Z 2) is controlled by coulombic energy loss in the atmosphere.

Age and seasonal differences in the synthesis and metabolism of testosterone by testicular tissue and pineal HIOMT activity of Uinta ground squirrels (Spermophilus armatus)

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

Ellis, L.C.; Balph, D.F.

Male Uinta ground squirrels (Spermophilus armatus) were sacrificed from a free-living population during the breeding season, which immediately followed emergence from hibernation; after the reproductive season; and just prior to aestivation/hibernation. HIOMT activity of the pineal gland was assayed and related to the ability of the gonads to synthesize and metabolize testosterone. Older squirrels had higher HIOMT activity than did the younger animals. The activity of this enzyme was lowest in squirrels during the breeding season. HIOMT activity increased after the breeding season to its highest level just before the squirrels enter aestivation/hibernation. At this time, testicular weight increased concomitantmore » with an apparent increase in HIOMT activity. Testicular size and weight were largest at the time of emergence of the animals from hibernation. Androgen synthesis was also greatest during the breeding season. As would be expected, both decreased rapidly thereafter. The testes formed little 17..cap alpha..,20..cap alpha..-dihydroxyprogesterone during or after the breeding season, contrary to what has been reported for rats and house sparrows. The older squirrels demonstrated a greater capacity for testosterone metabolism during the breeding season than did the younger animals.« less

Fluorescence alteration of MPA capped CdSe quantum dots by spontaneous biomarker protein adsorption.

PubMed

Rowley, Amber; Parks, Tegan; Parks, Kaden; Medley, Kyle; Cordner, Alex; Yu, Ming

2018-05-23

Quantum dots (QDs) have significant potentials in biomedical applications of bioimaging and biosensing. Spontaneous adsorption of proteins on QDs surface is a common phenomenon, which occurred to serum proteins in biological samples, and has been observed to enhance QDs fluorescence. In this study, fluorescence alteration of 3-mercaptopropionic acid (MPA) capped CdSe quantum dots by four individual biomarker proteins was investigated. By monitoring the fluorescence emission of QDs, the biomarker protein adsorbed spontaneously on QDs surface was recognized and quantified. When alpha fetoprotein (AFP) or heat shock protein 90 alpha (HSP90α) were present, the QDs became brighter. The presence of cytochrome C (CytoC) or lysozyme (Lyz) made the QDs dimmer first, and then brighter. Within 5 min response time all four biomarker proteins were detected individually with the estimated detection limit in the range of 1-10 ng/mL and good linear dynamic ranges. The results suggested that the fluorescence of QDs was responsive to not only serum proteins but also biomarker proteins. The fluorescence response was able to correlate quantitatively with the amount of biomarker proteins in relatively low concentrations. These results provide more information to understand QDs and support their applications in biomedical fields. Copyright © 2018. Published by Elsevier Inc.

Role of calcium in the constriction of isolated cerebral arteries

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

Wendling, W.W.

1987-01-01

Calcium entry blockers (CEB) have been used in the experimental treatment or prevention of many cerebrovascular disorders including stroke, post-ischemic hypoperfusion after cardiac arrest, cerebral vasospasm after subarachnoid hemorrhage, and migraine headache. However, the mechanism of action of these drugs on the cerebral circulation is poorly understood. This study examined the effects of calcium antagonists, Ca/sup 2 +/-deficient solutions, and vasocostrictors on cerebrovascular tone and /sup 45/Ca fluxes, to determine the role of calcium in cerebral arterial constriction. A Scatchard plot of /sup 45/Ca binding to BMCA showed that Ca/sup 2 +/ was bound at either low or high affinitymore » binding sties. The four vasoconstrictors (potassium, serotonin, PGF/sub 2 ..cap alpha../, or SQ-26,655) each increased low affinity /sup 45/Ca uptake into BMCA. The results demonstrate that: (1) Potassium and serotonin constrict BMCA mainly by promoting Ca/sup 2 +/ influx through CEB-sensitive channels; (2) PGF/sub 2 ..cap alpha../ and SQ-26,655 constrict BMCA in part by promoting Ca/sup 2 +/ influx through CEB-sensitive channels, and in part by releasing Ca/sup 2 +/ from depletable internal stores; (3) The major action of CEB on BMCA is to block vasoconstrictor-induced Ca/sup 2 +/ uptake through both potential-operated (K/sup +/-stimulated) and receptor-operated channels.« less

Neutral amino acid transport across brain microvessel endothelial cell monolayers

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

Audus, K.L.; Borchardt, R.T.

1986-03-01

Brain microvessel endothelial cells (BMEC) which form the blood-brain barrier (BBB) possess an amino acid carrier specific for large neutral amino acids (LNAA). The carrier is important for facilitating the delivery of nutrient LNAA's and centrally acting drugs that are LNAA's, to the brain. Bovine BMEC's were isolated and grown up to complete monolayers on regenerated cellulose-membranes in primary culture. To study the transendothelial transport of leucine, the monolayers were placed in a side-by-side diffusion cell, and transport across the monolayers followed with (/sup 3/H)-leucine. The transendothelial transport of leucine in this in vitro model was determined to be bidirectional,more » and time-, temperature-, and concentration-dependent. The transport of leucine was saturable and the apparent K/sub m/ and V/sub max/, 0.18 mM and 6.3 nmol/mg/min, respectively. Other LNAA's, including the centrally acting drugs, ..cap alpha..-methyldopa, L-DOPA, ..cap alpha..-methyl-tyrosine, and baclofen, inhibited leucine transport. The leucine carrier was also found to be stereospecific and not sensitive to inhibitors of active transport. These results are consistent with previous in vitro and in vivo studies. Primary cultures of BMEC's appear to be a potentially important tool for investigating at the cellular level, the transport mechanisms of the BBB.« less

Imidazoline ring cleavage in 1,3,6,10-tetraazatetracyclo-(7. 3. 1. 0/sup 2,7/. 0/sup 6,13/)trideca-4,11-dienes, leading to the formation of diquinoxalino(1,2-. cap alpha. :2',3'-d)pyrrole derivatives

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

Charushin, V.N.; Petrova, G.M.; Aleksandrov, G.G.

1987-10-01

Dibenzo(d,k)-1,3,6,10-tetraazatetracyclo(7.3.1.0/sup 2,7/.0/sup 6,13/) trideca-4,11-dienes undergo addition reactions at the C/sub (2)/ carbon atom with alcohols and thiols, accompanied by cleavage of the C-N bond of the imidazoline ring, to generate diquinoxalino(1,2-..cap alpha..:2',3'-d)pyrrole derivatives. /sup 1/H NMR spectra were recorded on Perkin-Elmer R 12B (60 MHz) and Bruker WH-90 spectrometer for CDCl/sub 3/ solutions at 40/sup 0/C and with TMS as internal standard. /sup 13/C NMR spectra were obtained on a Bruker WH-90 (22.62 MHz) spectrometer. /sup 13/C chemical shifts were measured relative to solvent signals (deltaCDCl/sub 3/ 77.0 ppm). /sup 13/C NMR spectra of compounds IIa and g were takenmore » using full spin-spin carbon-proton decoupling. In order to measure SSCC the spectrum was recorded both with proton coupling and also with selective decoupling of individual protons and their attached /sup 13/C carbon nuclei.« less

Characterization of HeLa 5'-nucleotidase: a stable plasma membrane marker

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

Brake, E.T.; Will, P.C.; Cook, J.S.

1977-11-22

The enzyme 5'-nucleotidase, assayed as 5'-AMPase, has been extensively characterized and established as a stable, quantitative plasma membrane marker in HeLa S3 cells. The 5'-AMPase has a K/sub m/ of 7.0 ..mu..m. There are activity optima at pH7 and 10; the latter is Mg/sup 2 +/-dependent. The membrane preparations have a small amount of acid phosphatase activity that is distinct from 5'-AMPase activity but no alkaline phosphatase. ADP, ATP and ..cap alpha.., ..beta..-methylene adenosine-5'-diphosphate are strongly inhibitory. Mg/sup 2 +/, Ca/sup 2 +/, or Co/sup 2 +/ do not affect the pH 7.0 activity; Mn/sup 2 +/ activates slightly, whereasmore » Zn/sup 2 +/, Cu/sup 2 +/, and Ni/sup 2 +/ are inhibitory. EDTA slowly inactivates, but removal of the EDTA without the addition of divalent cations restores activity. The inactivation is also substantially reversed by Co/sup 2 +/ or Mn/sup 2 +/. ConA strongly inhibits, and ..cap alpha..-methyl-D-mannoside or glucose relieves the inhibition, indicating that the 5'-AMPase is a glycoprotein. Histidine is also inhibitory. Ouabain, phloretin, cytochalasin B, cysteine, phenylalanine, N-ethylmaleimide, and iodoacetic acid are without effect.« less

Anisotropy of the Fermi surface, Fermi velocity, many-body enhancement, and superconducting energy gap in Nb

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

Crabtree, G.W.; Dye, D.H.; Karim, D.P.

1987-02-01

The detailed angular dependence of the Fermi radius k/sub F/, the Fermi velocity v/sub F/(k), the many-body enhancement factor lambda(k), and the superconducting energy gap ..delta..(k), for electrons on the Fermi surface of Nb are derived with use of the de Haas--van Alphen (dHvA) data of Karim, Ketterson, and Crabtree (J. Low Temp. Phys. 30, 389 (1978)), a Korringa-Kohn-Rostoker parametrization scheme, and an empirically adjusted band-structure calculation of Koelling. The parametrization is a nonrelativistic five-parameter fit allowing for cubic rather than spherical symmetry inside the muffin-tin spheres. The parametrized Fermi surface gives a detailed interpretation of the previously unexplained kappa,more » ..cap alpha..', and ..cap alpha..'' orbits in the dHvA data. Comparison of the parametrized Fermi velocities with those of the empirically adjusted band calculation allow the anisotropic many-body enhancement factor lambda(k) to be determined. Theoretical calculations of the electron-phonon interaction based on the tight-binding model agree with our derived values of lambda(k) much better than those based on the rigid-muffin-tin approximation. The anisotropy in the superconducting energy gap ..delta..(k) is estimated from our results for lambda(k), assuming weak anisotropy.« less

Polyamidoamine dendrimers-capped carbon dots/Au nanocrystal nanocomposites and its application for electrochemical immunosensor.

PubMed

Gao, Qi; Han, Jingman; Ma, Zhanfang

2013-11-15

In this work, polyamidoamine dendrimers capped-carbon dots (PAMAM-CDs) were fabricated by one-step microwave assisted pyrolysis of citric acid (CA) and PAMAM, where the formation of CDs and the surface passivation were accomplished simultaneously. The obtained graphitic PAMAM-CDs, with abundant amine groups, were employed as reducing and capping agents for the formation of PAMAM-CDs/Au nanocrystal nanocomposites. The resulting nanocomposites exhibited excellent conductivity, stability and biocompatibility on the surface of electrode and were designed as an immobilized matrix for sensitive immunosensing of alpha-fetoprotein (AFP). The proposed immunosensor showed a wide linear detection range from 100 fg mL(-1) to 100 ng mL(-1). The detection limit for AFP was 0.025 pg mL(-1). Importantly, the immunosensor was evaluated for the analysis of clinical serum samples, obtaining a good correlation with enzyme-linked immunosorbent assay (ELISA). The results indicated that the immunosensor provided a possible application for the detection of AFP in clinical diagnosis. Copyright © 2013 Elsevier B.V. All rights reserved.

Systematic analysis of α elastic scattering with the São Paulo potential

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

Charry-Pastrana, F. E., E-mail: feecharrypa@unal.edu.co; Pinilla, E. C.

2016-07-07

We describe systematically by collision energy and target mass, alpha elastic scattering angular distributions by using the São Paulo potential as the real part of the optical potential. The imaginary part is proportional to the real one by a factor N{sub i}. We find this parameter by fitting the theoretical angular distributions to the experimental cross sections through a χ{sup 2} minimization. The N{sub i} and their respective uncertainties, σ{sub Ni}, fall in the range 0.4 ≤ N{sub i} ± σ{sub N{sub i}} ≤ 0.8 for all the systems studied.

Validation of the French version of the Child Post-Traumatic Stress Reaction Index: psychometric properties in French speaking school-aged children.

PubMed

Olliac, Bertrand; Birmes, Philippe; Bui, Eric; Allenou, Charlotte; Brunet, Alain; Claudet, Isabelle; Sales de Gauzy, Jérôme; Grandjean, Hélène; Raynaud, Jean-Philippe

2014-01-01

Although the reliable and valid Child Post-Traumatic Stress Reaction Index (CPTS-RI) is a widely used measure of posttraumatic stress disorder (PTSD) symptoms in children, it has not been validated in French-speaking populations. The present study aims to assess the psychometric properties of the CPTS-RI in three samples of French-speaking school-children. Data was obtained from three samples. Sample 1 was composed of 106 children (mean (SD) age = 11.7(0.7), 50% females) victims of an industrial disaster. Sample 2 was composed of 50 children (mean (SD) age = 10.8(2.6), 44% females) who had received an orthopaedic surgical procedure after an accident. Sample 3 was composed of 106 children (mean (SD) age = 11.7(2.2), 44% females) admitted to an emergency department after a road traffic accident. We tested internal consistency using Cronbach's alpha. We examined test-retest reliability using intraclass correlation coefficient. In order to assess the convergent validity of the French version of the CPTS-RI and the Clinician Administered PTS Scale-Child and Adolescent (CAPS-CA), spearman-correlation coefficient was computed. To verify the validity of the cut-off scores, a ROC curve was constructed which evaluated the sensitivity and specificity of each score compared to the diagnosis with the CAPS-CA. We also used principal components analysis with varimax rotation to study the structure of the French version of the CPTS-RI. Cronbach's alpha coefficient was 0.87 for the French version of the CPTS-RI. Two-week test-retest intraclass correlation coefficient (n = 30) was 0.67. The French version of the CPTS-RI was well correlated with the CAPS-CA (r = 0.76, p < 0.001). Taking the CAPS-CA as the diagnostic reference, with a diagnostic cut-off of >24 for the CPTS-RI, the sensitivity and specificities were 100% and 62.6%, respectively. The French version of the CPTS-RI demonstrated a three-factor structure. The CPTS-RI is reliable and valid in French-speaking children.

Introduction of potential helix-capping residues into an engineered helical protein.

PubMed

Parker, M H; Hefford, M A

1998-08-01

MB-1 is an engineered protein that was designed to incorporate high percentages of four amino acid residues and to fold into a four-alpha-helix bundle motif. Mutations were made in the putative loop I and III regions of this protein with the aim of increasing the stability of the helix ends. Four variants, MB-3, MB-5, MB-11 and MB-13, have replacements intended to promote formation of an 'N-capping box'. The loop I and III sequences of MB-3 (both GDLST) and MB-11 (GGDST) were designed to cause alphaL C-terminal 'capping' motifs to form in helices I and III. MB-5 has a sequence, GPDST, that places proline in a favourable position for forming beta-turns, whereas MB-13 (GLDST) has the potential to form Schellman C-capping motifs. Size-exclusion chromatography suggested that MB-1, MB-3, MB-5, MB-11 and MB-13 all form dimers, or possibly trimers. Free energies for the unfolding of each of these variants were determined by urea denaturation, with the loss of secondary structure followed by CD spectroscopy. Assuming an equilibrium between folded dimer and unfolded monomer, MB-13 had the highest apparent stability (40.5 kJ/mol, with +/-2.5 kJ/mol 95% confidence limits), followed by MB-11 (39.3+/-5.9 kJ/mol), MB-3 (36.4+/-1.7 kJ/mol), MB-5 (34.7+/-2.1 kJ/mol) and MB-1 (29.3+/-1.3 kJ/mol); the same relative stabilities of the variants were found when a folded trimer to unfolded monomer model was used to calculate stabilities. All of the variants were relatively unstable for dimeric proteins, but were significantly more stable than MB-1. These findings suggest that it might be possible to increase the stability of a protein for which the three-dimensional structure is unknown by placing amino acid residues in positions that have the potential to form helix- and turn-stabilizing motifs.

Novel rechargeable calcium phosphate nanocomposite with antibacterial activity to suppress biofilm acids and dental caries.

PubMed

Al-Dulaijan, Yousif A; Cheng, Lei; Weir, Michael D; Melo, Mary Anne S; Liu, Huaibing; Oates, Thomas W; Wang, Lin; Xu, Hockin H K

2018-05-01

Rechargeable calcium phosphate (CaP) composites were developed recently. However, none of the rechargeable CaP composites was antibacterial. The objectives of this study were to develop the first rechargeable CaP composite that was antibacterial, and to investigate the effects of adding dimethylaminohexadecyl methacrylate (DMAHDM) into rechargeable CaP composite on ion rechargeability and re-release as well as biofilm properties. DMAHDM was synthesized via a Menschutkin reaction. Nanoparticles of amorphous calcium phosphate (NACP) were synthesized using a spray-drying technique. The resin contained ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM). Two composites were fabricated: rechargeable NACP composite, and rechargeable NACP-DMAHDM composite. Mechanical properties and ion release and recharge were measured. A dental plaque microcosm biofilm model using saliva was tested. Flexural strength and elastic modulus of rechargeable NACP and NACP-DMAHDM composites matched commercial control composite (p > 0.1). NACP-DMAHDM inhibited biofilm metabolic activity and lactic acid, and reduced biofilm colony-forming units (CFU) by 3-4 log. NACP and NACP-DMAHDM showed similar Ca and P ion recharge and re-release (p > 0.1). Therefore, adding DMAHDM did not compromise the ion rechargeability. One recharge yielded continuous release for 42 d. The release was maintained at the same level with increasing number of recharge cycles, indicating long-term ion release and remineralization capability. The first CaP rechargeable and antibacterial composite was developed. Adding DMAHDM into the rechargeable NACP composite did not adversely affect the Ca and P ion release and recharge, and the composite had much less biofilm growth and lactic acid production, with CFU reduction by 3-4 log. This novel CaP rechargeable composite with long-term remineralization and antibacterial properties is promising for tooth restorations to inhibit caries. Copyright © 2018 Elsevier Ltd. All rights reserved.

All-night EEG power spectral analysis of the cyclic alternating pattern components in young adult subjects.

PubMed

Ferri, Raffaele; Bruni, Oliviero; Miano, Silvia; Plazzi, Giuseppe; Terzano, Mario G

2005-10-01

To analyze in detail the frequency content of the different EEG components of the Cyclic Alternating Pattern (CAP), taking into account the ongoing EEG background and the nonCAP (NCAP) periods in the whole night polysomnographic recordings of normal young adults. Sixteen normal healthy subjects were included in this study. Each subject underwent one polysomnographic night recording; sleep stages were scored following standard criteria. Subsequently, each CAP A phase was detected in all recordings, during NREM sleep, and classified into 3 subtypes (A1, A2, and A3). The same channel used for the detection of CAP A phases (C3/A2 or C4/A1) was subdivided into 2-s mini-epochs. For each mini-epoch, the corresponding CAP condition was determined and power spectra calculated in the frequency range 0.5-25 Hz. Average spectra were obtained for each CAP condition, separately in sleep stage 2 and SWS, for each subject. Finally, the first 6h of sleep were subdivided into 4 periods of 90 min each and the same spectral analysis was performed for each period. During sleep stage 2, CAP A subtypes differed from NCAP periods for all frequency bins between 0.5 and 25 Hz; this difference was most evident for the lowest frequencies. The B phase following A1 subtypes had a power spectrum significantly higher than that of NCAP, for frequencies between 1 and 11 Hz. The B phase after A2 only differed from NCAP for a small but significant reduction in the sigma band power; this was evident also after A3 subtypes. During SWS, we found similar results. The comparison between the different CAP subtypes also disclosed significant differences related to the stage in which they occurred. Finally, a significant effect of the different sleep periods was found on the different CAP subtypes during sleep stage 2 and on NCAP in both sleep stage 2 and SWS. CAP subtypes are characterized by clearly different spectra and also the same subtype shows a different power spectrum, during sleep stage 2 or SWS. This finding underlines a probable different functional meaning of the same CAP subtype during different sleep stages. We also found 3 clear peaks of difference between CAP subtypes and NCAP in the delta, alpha, and beta frequency ranges which might indicate the presence of 3 frequency components characterizing CAP subtypes, in different proportion in each of them. The B component of CAP differs from NCAP because of a decrease in power in the sigma frequency range. This study shows that A components of CAP might correspond to periods in which the very-slow delta activity of sleep groups a range of different EEG activities, including the sigma and beta bands, while the B phase of CAP might correspond to a period in which this activity is quiescent or inhibited.

First-Principles and Thermodynamic Simulation of Elastic Stress Effect on Energy of Hydrogen Dissolution in Alpha Iron

NASA Astrophysics Data System (ADS)

Rakitin, M. S.; Mirzoev, A. A.; Mirzaev, D. A.

2018-04-01

Mobile hydrogen, when dissolving in metals, redistributes due to the density gradients and elastic stresses, and enables destruction processes or phase transformations in local volumes of a solvent metal. It is rather important in solid state physics to investigate these interactions. The first-principle calculations performed in terms of the density functional theory, are used for thermodynamic simulation of the elastic stress effect on the energy of hydrogen dissolution in α-Fe crystal lattice. The paper presents investigations of the total energy of Fe-H system depending on the lattice parameter. As a result, the relation is obtained between the hydrogen dissolution energy and stress. A good agreement is shown between the existing data and simulation results. The extended equation is suggested for the chemical potential of hydrogen atom in iron within the local stress field. Two parameters affecting the hydrogen distribution are compared, namely local stress and phase transformations.

Mechanism of the lysosomal membrane enzyme acetyl coenzyme A: alpha-glucosaminide N-acetyltransferase

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

Bame, K.J.

1986-01-01

Acetyl-CoA:..cap alpha..-glucosaminide N-acetyltransferase is a lysosomal membrane enzyme, deficient in the genetic disease Sanfilippo C syndrome. The enzyme catalyzes the transfer of an acetyl group from cytoplasmic acetyl-CoA to terminal ..cap alpha..-glucosamine residues of heparan sulfate within the organelle. The reaction mechanism was examined using high purified lysosomal membranes from rat liver and human fibroblasts. The N-acetyltransferase reaction is optimal above pH 5.5 and a 2-3 fold stimulation of activity is observed in the presence of 0.1% taurodeoxycholate. Double reciprocal analysis and product inhibition studies indicate that the enzyme works by a Di-Iso Ping Pong Bi Bi mechanism. The bindingmore » of acetyl-CoA to the enzyme is measured by exchange label from (/sup 3/H)CoA to acetyl-CoA, and is optimal at pH's above 7.0. The acetyl-enzyme intermediate is formed by incubating membranes with (/sup 3/H)acetyl-CoA. The acetyl group can be transferred to glucosamine, forming (/sup 3/H)N-acetylglucosamine; the transfer is optimal between pH 4 and 5. Lysosomal membranes from Sanfilippo C fibroblasts confirm that these half reactions carried out by the N-acetyltransferase. The enzyme is inactivated by N-bromosuccinimide and diethylpyrocarbonate, indicating that a histidine is involved in the reaction. These results suggest that the histidine residue is at the active site of the enzyme. The properties of the N-acetyltransferase in the membrane, the characterization of the enzyme kinetics, the chemistry of a histidine mediated acetylation and the pH difference across the lysosomal membrane all support a transmembrane acetylation mechanism.« less

Large-scale models reveal the two-component mechanics of striated muscle.

PubMed

Jarosch, Robert

2008-12-01

This paper provides a comprehensive explanation of striated muscle mechanics and contraction on the basis of filament rotations. Helical proteins, particularly the coiled-coils of tropomyosin, myosin and alpha-actinin, shorten their H-bonds cooperatively and produce torque and filament rotations when the Coulombic net-charge repulsion of their highly charged side-chains is diminished by interaction with ions. The classical "two-component model" of active muscle differentiated a "contractile component" which stretches the "series elastic component" during force production. The contractile components are the helically shaped thin filaments of muscle that shorten the sarcomeres by clockwise drilling into the myosin cross-bridges with torque decrease (= force-deficit). Muscle stretch means drawing out the thin filament helices off the cross-bridges under passive counterclockwise rotation with torque increase (= stretch activation). Since each thin filament is anchored by four elastic alpha-actinin Z-filaments (provided with force-regulating sites for Ca(2+) binding), the thin filament rotations change the torsional twist of the four Z-filaments as the "series elastic components". Large scale models simulate the changes of structure and force in the Z-band by the different Z-filament twisting stages A, B, C, D, E, F and G. Stage D corresponds to the isometric state. The basic phenomena of muscle physiology, i. e. latency relaxation, Fenn-effect, the force-velocity relation, the length-tension relation, unexplained energy, shortening heat, the Huxley-Simmons phases, etc. are explained and interpreted with the help of the model experiments.

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

Hawkins, C.A.

Tests of QED to order ..cap alpha../sup 4/ performed with the ASP detector at PEP are presented. Measurements have been made of exclusive e/sup +/e/sup -/e/sup +/e/sup -/, e/sup +/e/sup -/..gamma gamma.. and ..gamma gamma gamma gamma.. final states with all particles above 50 milliradians with respect to the e/sup +/e/sup -/ beam line. These measurements represent a significant increase in statistics over previous measurements. All measurements agree well with theoretical predictions. 5 refs., 1 tab.

Binding Linkage in a Telomere DNA–Protein Complex at the Ends of Oxytricha nova Chromosomes

PubMed Central

Buczek, Pawel; Orr, Rochelle S.; Pyper, Sean R.; Shum, Mili; Ota, Emily Kimmel Irene; Gerum, Shawn E.; Horvath, Martin P.

2005-01-01

Alpha and beta protein subunits of the telomere end binding protein from Oxytricha nova (OnTEBP) combine with telomere single strand DNA to form a protective cap at the ends of chromosomes. We tested how protein–protein interactions seen in the co-crystal structure relate to DNA binding through use of fusion proteins engineered as different combinations of domains and subunits derived from OnTEBP. Joining alpha and beta resulted in a protein that bound single strand telomere DNA with high affinity (KD-DNA=1.4 nM). Another fusion protein, constructed without the C-terminal protein–protein interaction domain of alpha, bound DNA with 200-fold diminished affinity (KD-DNA=290 nM) even though the DNA-binding domains of alpha and beta were joined through a peptide linker. Adding back the alpha C-terminal domain as a separate protein restored high-affinity DNA binding. The binding behaviors of these fusion proteins and the native protein subunits are consistent with cooperative linkage between protein-association and DNA-binding equilibria. Linking DNA–protein stability to protein–protein contacts at a remote site may provide a trigger point for DNA–protein disassembly during telomere replication when the single strand telomere DNA must exchange between a very stable OnTEBP complex and telomerase. PMID:15967465

Biocompatible, Biodegradable, and Electroactive Polyurethane-Urea Elastomers with Tunable Hydrophilicity for Skeletal Muscle Tissue Engineering.

PubMed

Chen, Jing; Dong, Ruonan; Ge, Juan; Guo, Baolin; Ma, Peter X

2015-12-30

It remains a challenge to develop electroactive and elastic biomaterials to mimic the elasticity of soft tissue and to regulate the cell behavior during tissue regeneration. We designed and synthesized a series of novel electroactive and biodegradable polyurethane-urea (PUU) copolymers with elastomeric property by combining the properties of polyurethanes and conducting polymers. The electroactive PUU copolymers were synthesized from amine capped aniline trimer (ACAT), dimethylol propionic acid (DMPA), polylactide, and hexamethylene diisocyanate. The electroactivity of the PUU copolymers were studied by UV-vis spectroscopy and cyclic voltammetry. Elasticity and Young's modulus were tailored by the polylactide segment length and ACAT content. Hydrophilicity of the copolymer films was tuned by changing DMPA content and doping of the copolymer. Cytotoxicity of the PUU copolymers was evaluated by mouse C2C12 myoblast cells. The myogenic differentiation of C2C12 myoblasts on copolymer films was also studied by analyzing the morphology of myotubes and relative gene expression during myogenic differentiation. The chemical structure, thermal properties, surface morphology, and processability of the PUU copolymers were characterized by NMR, FT-IR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and solubility testing, respectively. Those biodegradable electroactive elastic PUU copolymers are promising materials for repair of soft tissues such as skeletal muscle, cardiac muscle, and nerve.

Evolution of elastic x-ray scattering in laser-shocked warm dense lithium.

PubMed

Kugland, N L; Gregori, G; Bandyopadhyay, S; Brenner, C M; Brown, C R D; Constantin, C; Glenzer, S H; Khattak, F Y; Kritcher, A L; Niemann, C; Otten, A; Pasley, J; Pelka, A; Roth, M; Spindloe, C; Riley, D

2009-12-01

We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4-ns-long laser pulses. Separate 1-ns-long laser pulses were used to generate a bright source of 2.96 keV Cl Ly- alpha photons for x-ray scattering, and the spectrum of scattered photons was recorded at a scattering angle of 120 degrees using a highly oriented pyrolytic graphite crystal operated in the von Hamos geometry. A variable delay between the heater and backlighter laser beams measured the scattering time evolution. Comparison with radiation-hydrodynamics simulations shows that the plasma is highly coupled during the first several nanoseconds, then relaxes to a moderate coupling state at later times. Near-elastic scattering amplitudes have been successfully simulated using the screened one-component plasma model. Our main finding is that the near-elastic scattering amplitudes are quite sensitive to the mean ionization state Z[over ] and by extension to the choice of ionization model in the radiation-hydrodynamics simulations used to predict plasma properties within the shocked Li.

Generation of human induced pluripotent stem cells using non-synthetic mRNA.

PubMed

Rohani, L; Fabian, C; Holland, H; Naaldijk, Y; Dressel, R; Löffler-Wirth, H; Binder, H; Arnold, A; Stolzing, A

2016-05-01

Here we describe some of the crucial steps to generate induced pluripotent stem cells (iPSCs) using mRNA transfection. Our approach uses a V. virus-derived capping enzyme instead of a cap-analog, ensuring 100% proper cap orientation for in vitro transcribed mRNA. V. virus' 2'-O-Methyltransferase enzyme creates a cap1 structure found in higher eukaryotes and has higher translation efficiency compared to other methods. Use of the polymeric transfection reagent polyethylenimine proved superior to other transfection methods. The mRNA created via this method did not trigger an intracellular immune response via human IFN-gamma (hIFN-γ) or alpha (hIFN-α) release, thus circumventing the use of suppressors. Resulting mRNA and protein were expressed at high levels for over 48h, thus obviating daily transfections. Using this method, we demonstrated swift activation of pluripotency associated genes in human fibroblasts. Low oxygen conditions further facilitated colony formation. Differentiation into different germ layers was confirmed via teratoma assay. Reprogramming with non-synthetic mRNA holds great promise for safe generation of iPSCs of human origin. Using the protocols described herein we hope to make this method more accessible to other groups as a fast, inexpensive, and non-viral reprogramming approach. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Comparison of U.S. Environmental Protection Agency's CAP88 PC Versions 3.0 and 4.0.

PubMed

Jannik, Tim; Farfan, Eduardo B; Dixon, Ken; Newton, Joseph; Sailors, Christopher; Johnson, Levi; Moore, Kelsey; Stahman, Richard

2015-08-01

The Savannah River National Laboratory (SRNL) with the assistance of Georgia Regents University, completed a comparison of the U.S. Environmental Protection Agency's (U.S. EPA) environmental dosimetry code CAP88 PC V3.0 with the recently developed V4.0. CAP88 is a set of computer programs and databases used for estimation of dose and risk from radionuclide emissions to air. At the U.S. Department of Energy's Savannah River Site, CAP88 is used by SRNL for determining compliance with U.S. EPA's National Emission Standards for Hazardous Air Pollutants (40 CFR 61, Subpart H) regulations. Using standardized input parameters, individual runs were conducted for each radionuclide within its corresponding database. Some radioactive decay constants, human usage parameters, and dose coefficients changed between the two versions, directly causing a proportional change in the total effective dose. A detailed summary for select radionuclides of concern at the Savannah River Site (60Co, 137Cs, 3H, 129I, 239Pu, and 90Sr) is provided. In general, the total effective doses will decrease for alpha/beta emitters because of reduced inhalation and ingestion rates in V4.0. However, for gamma emitters, such as 60Co and 137Cs, the total effective doses will increase because of changes U.S. EPA made in the external ground shine calculations.

Structural determination of importin alpha in complex with beak and feather disease virus capsid nuclear localization signal

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

Patterson, Edward I.; EH Graham Centre for Agricultural Innovation; Dombrovski, Andrew K.

2013-09-06

Highlights: •Circovirus capsid proteins contain large nuclear localization signals (NLS). •A method of nuclear import has not been elucidated. •Beak and feather disease virus (BFDV) capsid NLS was crystallized with importin α. •The structure showed BFDV NLS binding to the major site of importin α. •Result shows implications for mechanism of nuclear transport for all circoviruses. -- Abstract: Circoviruses represent a rapidly increasing genus of viruses that infect a variety of vertebrates. Replication requires shuttling viral molecules into the host cell nucleus, a process facilitated by capsid-associated protein (Cap). Whilst a nuclear localization signal (NLS) has been shown to mediatemore » nuclear translocation, the mode of nuclear transport remains to be elucidated. To better understand this process, beak and feather disease virus (BFDV) Cap NLS was crystallized with nuclear import receptor importin-α (Impα). Diffraction yielded structural data to 2.9 Å resolution, and the binding site on both Impα and BFDV Cap NLS were well resolved. The binding mechanism for the major site is likely conserved across circoviruses as supported by the similarity of NLSs in circovirus Caps. This finding illuminates a crucial step for infection of host cells by this viral family, and provides a platform for rational drug design against the binding interface.« less

Quantitative analysis of sleep EEG microstructure in the time-frequency domain.

PubMed

De Carli, Fabrizio; Nobili, Lino; Beelke, Manolo; Watanabe, Tsuyoshi; Smerieri, Arianna; Parrino, Liborio; Terzano, Mario Giovanni; Ferrillo, Franco

2004-06-30

A number of phasic events influence sleep quality and sleep macrostructure. The detection of arousals and the analysis of cyclic alternating patterns (CAP) support the evaluation of sleep fragmentation and instability. Sixteen polygraphic overnight recordings were visually inspected for conventional Rechtscaffen and Kales scoring, while arousals were detected following the criteria of the American Sleep Disorders Association (ASDA). Three electroencephalograph (EEG) segments were associated to each event, corresponding to background activity, pre-arousal period and arousal. The study was supplemented by the analysis of time-frequency distribution of EEG within each subtype of phase A in the CAP. The arousals were characterized by the increase of alpha and beta power with regard to background. Within NREM sleep most of the arousals were preceded by a transient increase of delta power. The time-frequency evolution of the phase A of the CAP sequence showed a strong prevalence of delta activity during the whole A1, but high amplitude delta waves were found also in the first 2/3 s of A2 and A3, followed by desynchronization. Our results underline the strict relationship between the ASDA arousals, and the subtype A2 and A3 within the CAP: in both the association between a short sequence of transient slow waves and the successive increase of frequency and decrease of amplitude characterizes the arousal response.

A direct vulnerable atherosclerotic plaque elasticity reconstruction method based on an original material-finite element formulation: theoretical framework

PubMed Central

Bouvier, Adeline; Deleaval, Flavien; Doyley, Marvin M; Yazdani, Saami K; Finet, Gérard; Le Floc'h, Simon; Cloutier, Guy; Pettigrew, Roderic I; Ohayon, Jacques

2016-01-01

The peak cap stress (PCS) amplitude is recognized as a biomechanical predictor of vulnerable plaque (VP) rupture. However, quantifying PCS in vivo remains a challenge since the stress depends on the plaque mechanical properties. In response, an iterative material finite element (FE) elasticity reconstruction method using strain measurements has been implemented for the solution of these inverse problems. Although this approach could resolve the mechanical characterization of VPs, it suffers from major limitations since (i) it is not adapted to characterize VPs exhibiting high material discontinuities between inclusions, and (ii) does not permit real time elasticity reconstruction for clinical use. The present theoretical study was therefore designed to develop a direct material-FE algorithm for elasticity reconstruction problems which accounts for material heterogeneities. We originally modified and adapted the extended FE method (Xfem), used mainly in crack analysis, to model material heterogeneities. This new algorithm was successfully applied to six coronary lesions of patients imaged in vivo with intravascular ultrasound. The results demonstrated that the mean relative absolute errors of the reconstructed Young's moduli obtained for the arterial wall, fibrosis, necrotic core, and calcified regions of the VPs decreased from 95.3±15.56%, 98.85±72.42%, 103.29±111.86% and 95.3±10.49%, respectively, to values smaller than 2.6 × 10−8±5.7 × 10−8% (i.e. close to the exact solutions) when including modified-Xfem method into our direct elasticity reconstruction method. PMID:24240392

On the Current Thermal State of Mars.

NASA Astrophysics Data System (ADS)

Grott, M.; Breuer, D.

2008-09-01

Introduction: The current thermal state of Mars is a fundamental unknown in Mars science. Although is has a huge influence on the planet's current geodynamic activity and controls the possibility for basal melting at the polar caps [1], constraints on this quantities are very scarce. This situation has lately been improved by the study of lithospheric deformation at the north polar cap [2] which constrained the current Martian elastic lithosphere thickness Te, an indirect measure of the temperatures in the planetary interior. Using radar sounding data obtained bySHARAD, the shallow radar onboard the Mars Reconnaissance Orbiter, [2] found that the current Martian lithosphere is extremely stiff and Te is larger than 300 km today. This is surprising as this value is almost twice as large as previously estimated from theoretical considerations and flexure studies [3][1]. In order to be consistent with the planets thermal evolution, [2] argue that the amount of radioactive elements in the Martian interior needs to be subchondritic. This appears to be problematic as geochemical analysis of the SNC meteorites implies higher concentrations of radioactive elements [4]. Furthermore, if the concentration of heat producing elements is indeed reduced, the resulting low interior temperatures will inhibit partial mantle melting and magmatism. However, geological evidence suggests that Mars has been volcanically active in the recent past [5]. In order to address these inconsistencies, we reinvestigate the thermal evolution of Mars and examine its current thermal state for a wide range of initial condition using the current elastic thickness Te and the potential for partial mantle melting to constrain our models. Modeling: We investigate the thermal evolution of Mars by solving the energy balance equations for the core and mantle, treating the mantle energy transport by parametrized convection models. This is done using scaling laws for stagnant lid convection and our model is similar to that of [3]. We ignore crustal production and assume that the bulk of the crust is primordial. Starting from given initial conditions the thermal evolution of Mars is calculated and the current elastic thickness and mantle temperatures are evaluated. Elastic thicknesses are calculated using the strength envelope formalism for given crustal and mantle rheologies [3] and the potential for partial mantle melting is parameterized using the minimum temperature difference between the mantle temperature and the solidus of peridotite which is given by [6]. Partial melting will occur if temperatures locally exceeds the solidus of peridotite Tsol. As lateral inhomogeneities due to thickness variations of the insulating crust can locally increase temperatures by up to 100 K [7] and plumes rising from the coremantle boundary may further increase temperatures by up to 50 K, we will assume that partial mantle melting is feasible if temperatures are lower than Tsol by at most 150 K. Parameters: The current thermal state of Mars is most sensitive to the amount and distribution of radioactive ele- ments and the efficiency of mantle energy transport, which is a strong function of mantle viscosity. We vary the fraction of radiogenic elements in the crust ? between 20 and 80 % and the fraction of radiogenic elements with respect to the reference compositional model ? [4] between 30 and 100 %. The reference mantle viscosity at 1600 K was varied between ?0 = 1019 and 1021 Pa s, corresponding to wet and dry olivine rheologies. Other parameters were kept constant and we use an initial upper mantle temperature of 1800 K, an initial core temperature of 2100 K, a crustal thermal conductivity of 3 W m-1 K-1, a mantle thermal conductivity of 4 W m-1 K-1 and a crustal thickness of 50 km. Fig. 1 shows the temperature structure of one model having 50 % of the radioactive elements in the crust (? = 0.5) and the fraction of radiogenic elements with respect to the reference model is 70 % ? = 0.7. As a comparison, the solidus and liquidus of peridotite are also given. The minimum temperature difference between mantle temperature and solidus is ˜250 K, not allowing for partial mantle melting. Results: Fig. 2 shows contour plots of the elastic thickness Te as a function of the fraction of radiogenic elements in the crust ? and the fraction of radiogenic elements with respect to the reference model ? [4] for (a) a wet mantle rheology and ?0 = 1019 Pa s and (c) a dry mantle rheology and ?0 = 1021 Pa s. Large elastic thicknesses require a small bulk concentration of radioactive elements ? or a large concentration of these elements in the crust ?. The gray areas in Fig.2 correspond to parameter combinations which satisfy the constrains given by Te > 300 km. Fig. 2 also shows contour plots of the minimum tempera- ture difference ?T as a function ? and ? for (b) wet and (d) dry mantle rheologies. Small ?T requires a large bulk concentration of radioactive elements ? or a small concentration of these elements in the crust ?. The gray areas correspond to parameter combinations which satisfy the constrains given by ?T < 150 K. There are no parameter combinations which satisfy both constrains given by Te > 300 km and ?T < 150 K for wet and dry mantle rheologies. The discrepancy is much larger for wet mantle rheologies than for dry ones. Conclusions: The constrains given by large elastic thicknesses and the potential for partial melting in the upper mantle cannot simultaneously be fulfilled using current models. This implies that either the elastic thickness is smaller than determined by [2], that the mantle solidus has been overestimated or that the polar caps are not currently in dynamic equilibrium. If the north polar cap contained CO2 ice, the permittivity of the cap would be reduced [8], allowing for larger deflections [2] and lower elastic thicknesses. This possibility needs to be investigated and the amount of CO2 ice necessary to sufficiently reduce Te should be determined in future work. Also, the solidus of mantle rocks depends on the rock'swater content and this effect should be incorporated into the models as a next step. Together, these effects will possibly allow for combinations of parameters ? and ? which satisfy the elastic thickness and partial melt constrains. Also, for the thermal models presented here, viscoelastic relaxation calculations should be carried out. References: [1] M.A.Wieczorek, Icarus, 10.1016/ j.icarus. 2007.10.026 (2008). [2] R.J. Phillips et al., Science 320, 5880, 1182 (2008) [3] M. Grott, D. Breuer, Icarus 193, 503 (2008). [4] H. Wänke and G. Dreibus, Philos. Trans. R. Soc. London Ser. A 349, 285 (1994). [5] G. Neukum et al., Nature 432, 971 (2004). [6] E. Takahashi, J. Geophys. Res. 95, B10, 1594115954 (1990). [7] S. Schumacher, D. Breuer, Geophys. Res. Lett., 34, 14, L14202 (2007) [8] E. Pettinelli et al, J. Geophyss Res. 108, E4, 101, 8029 (2003)

Passive radon/thoron personal dosimeter using an electrostatic collector and a diffused-junction detector

NASA Astrophysics Data System (ADS)

Bigu, J.; Raz, R.

1985-01-01

A solid-state alpha dosimeter has been designed and tested suitable for personal and environmental radon/thoron monitoring. The dosimeter basically consists of an electrostatic collector and an alpha-particle counting system with spectroscopy capabilities. The sensitive volume (˜20 cm3) of the electrostatic collector consists of a cylindrically shaped metal wire screen and a diffused-junction silicon alpha-detector covered with a thin aluminized Mylar sheet. A dc voltage (˜500 V) is applied between the wire screen and the Mylar sheet, with the latter held at negative potential relative to the former. Data can be retrieved during or after sampling by means of a microcomputer (Epson HX20) via a RS-232 communication interface unit. The dosimeter has been calibrated in a large (26 m3) radon/thoron test facility. A linear relationship was found between the dosimeter's alpha-count and both radon gas concentration and radon daughter working level. The dosimeter is mounted on top of an ordinary miner's cap lamp battery and is ideally suited for personal monitoring in underground uranium mines and other working areas. The dosimeter presented here is a considerably improved version of an earlier prototype.

Prevalence of type I sensitization to alpha-gal in forest service employees and hunters.

PubMed

Fischer, J; Lupberger, E; Hebsaker, J; Blumenstock, G; Aichinger, E; Yazdi, A S; Reick, D; Oehme, R; Biedermann, T

2017-10-01

The production of IgE molecules specific to the carbohydrate galactose-α-1,3-galactose (alpha-gal) is known to induce delayed anaphylaxis against mammalian meat. Tick bites constitute the primary sensitization source, as ticks transfer alpha-gal in their saliva to a host during a bite. The reported prevalence of alpha-gal-specific IgE (alpha-gal-sIgE) positivity varies between different populations from diverse geographic regions. To investigate the prevalence of alpha-gal-sIgE positivity in a population of forest service employees who are highly exposed to ticks in comparison with a residential population and a historic sample. A cross-sectional study evaluating 300 forest service employees and hunters from southwest Germany was performed. Alpha-gal-sIgE levels were assessed by ImmunoCAP assay. The prevalence of alpha-gal-sIgE-positive individuals was compared with a matched cohort composed of a residential population and blood samples from forest service employees collected 15 years ago. In the study population, the prevalence of alpha-gal-sIgE-positive (≥0.10 kU A /L) individuals was 35.0%, whereas the prevalence of individuals with alpha-gal-sIgE levels ≥0.35 kU A /L was 19.3%. Alpha-gal-sIgE positivity was associated with total IgE levels and recent tick bites. Mammalian meat-induced delayed anaphylaxis was found in 8.6% of the participants with alpha-gal-sIgE levels ≥0.35 kU A /L. For forest service employees and hunters, the odds ratio for alpha-gal-sIgE positivity was 2.48 compared to the residential population. The prevalence of alpha-gal-sIgE positivity in the current and historic cohort was comparable. Forest service employees and hunters compose a population with a high prevalence of alpha-gal-sIgE positivity and carry a considerable risk of red meat allergy. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Revealing the X-Ray Emission Processes of Old Rotation-Powered Pulsars: XMM-Newton Observations of PSR B0950+08, PSR B0823+26 and PSR J2043+2740

NASA Technical Reports Server (NTRS)

Becker, Werner; Weisskopf, Martin C.; Tenant, Allyn F.; Jessmer, Axel; Zhang, Shiang N.

2004-01-01

We have completed part of a program to study the X-ray emission properties of old rotation-powered pulsars with XMM-Newton in order to probe and identify the origin of their X radiation. The X-ray emission from these old pulsars is largely dominated by non-thermal processes. None of the observed spectra required adding a thermal component consisting of either a hot polar cap or surface cooling emission to model the data. The energy spectrum of PSR B0950+08 is best described by a single power law of photon-index alpha = 1.93(sup +0.14)(sub -0.12). Three-sigma temperature upper limits for possible contributions from a heated polar cap or the whole neutron star surface are T(sup infinity)(sub pc) < 0.87 x 10(exp 6) K and T(sup infinity)(sub s) < 0.48 x 10(exp 6) K, respectively. We also find that the X-ray emission from PSR B0950+08 is pulsed with two peaks per rotation period. The phase separation between the two X-ray peaks is approx. 144 deg (maximum to maximum) which is similar to the pulse peak separation observed in the radio band at 1.4 GHz. The fraction of X-ray pulsed photons is approx. 30%. A phase resolved spectral analysis confirms the nonthermal nature of the pulsed emission and finds power law slopes of alpha = 2.4(sup +0.52)(sub -0.42) and alpha = 1.93(sup +0.29)(sub -0.24) for the pulse peaks P1 and P2, respectively. The spectral emission properties observed for PSR B0823+26 are similar to those of PSR B0950+08. Its energy spectrum is very well described by a single power law with photon-index alpha = 2.5(sup +0.52)(sub -0.24. Three-sigma temperature upper limits for thermal contributions from a hot polar cap or from the entire neutron star surface are T(sup infinity)(sub pc) < 1.17 x 10(exp 6) K and T(sup infinity)(sub s) < 0.5 x 10(exp 6) K, respectively. There is evidence for pulsed X-ray emission at the - 97% confidence level with a pulsed fraction of 49 +/- 22%. For PSR 52043+2740 we report the first detection of X-ray emission. A power law spectrum, or a combination of a thermal and a power law spectrum all yield acceptable descriptions of its X-ray spectrum. No X-ray pulses are detected from PSR J2043+2740 but the sensitivity is low - the 2-sigma pulsed fraction upper limit is 57% assuming a sinusoidal pulse profile.

Link between microstability and macrostability of plasmas

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

Litwin, C.

A mechanism linking high-frequency microinstabilities and the low-frequencymacrostability is proposed. The coupling is provided by the time-averagedforce, ponderomotive force, of unstable high-frequency waves. Two specificexamples of this phenomenon are discussed. It is shown that an..cap alpha..-particle loss-cone instability stabilizes the flute mode of anignited, axisymmetric mirror plasma. In tokamaks, the ion-whistler instability,driven by an anisotropic population of energetic particles, stabilizes theinternal kink mode for JET range of parameters.

Coupling ligand recognition to protein folding in an engineered variant of rabbit ileal lipid binding protein.

PubMed

Kouvatsos, Nikolaos; Meldrum, Jill K; Searle, Mark S; Thomas, Neil R

2006-11-28

We have engineered a variant of the beta-clam shell protein ILBP which lacks the alpha-helical motif that caps the central binding cavity; the mutant protein is sufficiently destabilised that it is unfolded under physiological conditions, however, it unexpectedly binds its natural bile acid substrates with high affinity forming a native-like beta-sheet rich structure and demonstrating strong thermodynamic coupling between ligand binding and protein folding.

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

Anderson, W.F.; Martinell, J.; Whitney, J.B. III

The group of diseases called the thalassemias is the largest single-gene health problem in the world according the World Health Organization. The thalassemias are lethal hereditary anemias in which the infants cannot make their own blood. Three mouse mutants are shown to be models of the human disease ..cap alpha..-thalassemia. However, since an additional gene is affected, these mutants represent a particularly severe condition in which death occurs in the homozygous embryo even before globin genes are activated. Phenotypic and genotypic characteristics are described. (ACR)

In-vivo measurement of lithium in the brain and other organs

DOEpatents

Vartsky, D.; Wielopolski, L.; LoMonte, A.F.; Ellis, K.J.; Cohn, S.H.

1983-08-26

An in-vivo method of measurement of the amount of lithium present in tissue and organs of breathing animals is described. The basis for the technique is the lithium-1 neutron interaction - /sup 6/Li(n,..cap alpha..)T. The lithium is irradiated with thermal neutrons to produce tritium atoms. The tritium diffuses into the tissues and is exhaled. By measuring the amount of tritium exhaled, the lithium concentration in the irradiated zone is determined.

Investigations in the ionosphere on Kosmos 378. VII. Simultaneous ground-based and satellite measurements of the parameters of the high latitude ionosphere

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

Afonin, V.V.; Gdalevich, G.L.; Gubskii, V.F.

1975-01-01

The parameters of the high-latitude ionospheric plasma at night were measured simultaneously in the winter of 1970 by Kosmos 378 and by the ground-based observatory at Noril'sk. A comparison of ground-based and satellite measurements showed good agreement of n/sub e/ when the Chapman approximation for the ..cap alpha..-layer and Jacchia's 1971 model of the upper atmosphere are used.

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

Akhtar, R.A.; Abdel-Latif, A.A.

Muscarinic cholinergic and ..cap alpha../sub 1/-adrenergic agonists provoke hydrolysis of PIP/sub 2/ into diacylglycerol (DG) and inositol trisphosphate (IP/sub 3/) in a wide variety of tissue. Recently, IP/sub 3/ has been shown to mobilize Ca/sup 2 +/ from ER in several permeabilized tissue preparations. Although rabbit cornea is enriched in ACh and NE, the physiological function of these neurotransmitters is unclear. The present studies were initiated to determine the effects of cholinergic and adrenergic agonists on PIP/sub 2/ turnover in the cornea. Addition of ACh or NE (50 ..mu..M each) to the /sup 32/P-labeled corneas for 10 min decreased themore » radioactivity in PIP/sub 2/ by 33 and 36%, and increased the radioactivity in phosphatidic acid by 72 and 52%, respectively. When the corneas were labeled with myo-(/sup 3/H)inositol, ACh and NE increased the accumulation of IP/sub 3/ by 92 and 48%, respectively. The effects of ACh and NE on phospholipid labeling and IP/sub 3/ accumulation were specifically inhibited by atropine (10 ..mu..M) and prazosin (10 ..mu..M), respectively. The data suggest the presence of muscarinic cholinergic and ..cap alpha../sub 1/-adrenergic receptors in the rabbit cornea. Furthermore, activation of these receptors leads to cleavage of PIP/sub 2/ into DG and IP/sub 3/ which may function as second messengers in this tissue.« less

Prevalence of. cap alpha. /sub 1/-antitrypsin heterozygotes (Pi MZ) in patients with obstructive pulmonary disease

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

Shigeoka, J.W.; Hall, W.J.; Hyde, R.W.

1976-01-01

An increased incidence of intermediate deficiency of serum ..cap alpha../sub 1/-antitrypsin resulting from Pi phenotype MZ has been reported in patients with chronic obstructive pulmonary disease (COPD) by some laboratories but not confirmed by others. Prevalence of Pi MZ was determined in patients with COPD among 502 subjects referred to a pulmonary function testing laboratory in a region with low concentrations of air pollutants. Control prevalences were obtained from 930 randomly selected subjects in the same community as well as from patients without COPD referred to the laboratory. Depending on criteria used to define COPD, 155 to 306 subjects hadmore » COPD. Pi MZ prevalence in subjects with COPD varied from 1.5 to 4 times the prevalence in the community control group and in the patients without COPD. This difference approached significance or was significant. Because Pi MZ was present in only 3.5 to 4.5% of patients with COPD, Pi MZ is not a major factor in the etiology of COPD in this community. The higher incidence of Pi MZ in patients with COPD reported by other investigators may be explained by small sample size, bias in selection of study or control population groups, or the development of COPD from interaction between Pi MZ and air pollutants or other factors not present in this community.« less

ROAM mutations causing increased expression of yeast genes: their activation by signals directed toward conjugation functions and their formation by insertion of tyl repetitive elements

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

Errede, B.; Cardillo, T.S.; Wever, G.

1980-01-01

Mechanisms available to eukaryotic organisms for the coordinate regulation of gene expression are being examined by genetic and biochemical characterization of an unusual mutation, CYC7-H2, which causes overproduction of iso-2-cytochrome c in the yeast Saccharomyces cerevisiae. The CYC7-H2 mutation causes approximately a twenty fold overproduction of iso-2-cytochrome c in haploid strains but only a one to four fold overproduction in MATa/MAT..cap alpha.. diploid strains. This regulation of overproduction has been characterized as a response to signals controlling conjugation in yeast. The CYC7-H2 mutation is closely related to other regulatory mutations occurring at the cargA, cargB and DUR1,2 loci which aremore » the structural genes for arginase, ornithine transaminase and urea amidolyase, respectively. Similar to the CYC7-H2 mutation, the mutations designated cargA/sup +/O/sup h/, cargB/sup +/O/sup h/ and durO/sup h/ cause constitutive production of their respective gene products at much lower levels in MATa/MAT..cap alpha.. diploid strains than in the corresponding haploid strains. Observations characterizing the regulation of overproduction in the CYC7-H2 mutant are presented with the additional and parallel observations for the O/sup h/ mutants.« less

Proteases induce secretion of collagenase and plasminogen activator by fibroblasts

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

Werb, Z.; Aggeler, J.

1978-04-01

We have observed that treatment of rabbit synovial fibroblasts with proteolytic enzymes can induce secretion of collagenase (EC 3.4.24.7) and plasminogen activator (EC 3.4.21.-). Cells treated for 2 to 24 hr with plasmin, trypsin, chymotrypsin, pancreatic elastase, papain, bromelain, thermolysin, or ..cap alpha..-protease but not with thrombin or neuraminidase secreted detectable amounts of collagenase within 16 to 48 hr. Treatment of fibroblasts with trypsin also induced secretion of plasminogen activator. Proteases initiated secretion of collagenase (up to 20 units per 10/sup 6/ cells per 24 hr) only when treatment produced decreased cell adhesion. Collagenase production did not depend on continuedmore » presence of proteolytic activity or on subsequent cell adhesion, spreading, or proliferation. Routine subculturing with crude trypsin also induced collagenase secretion by cells. Secretion of collagenase was prevented and normal spreading was obtained if the trypsinized cells were placed into medium containing fetal calf serum. Soybean trypsin inhibitor, ..cap alpha../sub 1/-antitrypsin, bovine serum albumin, collagen, and fibronectin did not inhibit collagenase production. Although proteases that induced collagenase secretion also removed surface glycoprotein, the kinetics of induction of cell protease secretion were different from those for removal of fibronectin. Physiological inducers of secretion of collagenase and plasminogen activator by cells have not been identified. These results suggest that extracellular proteases in conjunction with plasma proteins may govern protease secretion by cells.« less

Preferential sites for InAsP/InP quantum wire nucleation using molecular dynamics

NASA Astrophysics Data System (ADS)

Nuñez-Moraleda, Bernardo; Pizarro, Joaquin; Guerrero, Elisa; Guerrero-Lebrero, Maria P.; Yáñez, Andres; Molina, Sergio Ignacio; Galindo, Pedro Luis

2014-11-01

In this paper, stress fields at the surface of the capping layer of self-assembled InAsP quantum wires grown on an InP (001) substrate have been determined from atomistic models using molecular dynamics and Stillinger-Weber potentials. To carry out these calculations, the quantum wire compositional distribution was extracted from previous works, where the As and P distributions were determined by electron energy loss spectroscopy and high-resolution aberration-corrected Z-contrast imaging. Preferential sites for the nucleation of wires on the surface of the capping layer were studied and compared with (i) previous simulations using finite element analysis to solve anisotropic elastic theory equations and (ii) experimentally measured locations of stacked wires. Preferential nucleation sites of stacked wires were determined by the maximum stress location at the MD model surface in good agreement with experimental results and those derived from finite element analysis. This indicates that MD simulations based on empirical potentials provide a suitable and flexible tool to study strain dependent atom processes.

Mirrors in the PDB: left-handed alpha-turns guide design with D-amino acids.

PubMed

Annavarapu, Srinivas; Nanda, Vikas

2009-09-22

Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Propensities for amino acids to occur in contiguous alpha(L) helices correlate with published thermodynamic scales for incorporation of D-amino acids into alpha(R) helices. Two backbone rules for terminating a left-handed helix are found: an alpha(R) conformation is disfavored at the amino terminus, and a beta(R) conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to alpha(L) helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. By examining left-handed alpha-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed alpha-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds.

Three-dimensional lattice matching of epitaxially embedded nanoparticles

NASA Astrophysics Data System (ADS)

May, Brelon J.; Anderson, Peter M.; Myers, Roberto C.

2017-02-01

For a given degree of in-plane lattice mismatch between a two-dimensional (2D) epitaxial layer and a substrate (ɛIP*), there is a critical thickness above which interfacial defects form to relax the elastic strain energy. Here, we extend the 2D lattice-matching conditions to three-dimensions in order to predict the critical size beyond which epitaxially encased nanoparticles, characterized by both ɛIP* and out-of-plane lattice mismatch (ɛOP*), relax by dislocation formation. The critical particle length (Lc) at which defect formation proceeds is determined by balancing the reduction in elastic energy associated with dislocation introduction with the corresponding increase in defect energy. Our results, which use a modified Eshelby inclusion technique for an embedded, arbitrarily-faceted nanoparticle, provide new insight to the nanoepitaxy of low dimensional structures, especially quantum dots and nanoprecipitates. By engineering ɛIP* and ɛOP* , the predicted Lc for nanoparticles can be increased to well beyond the case of encapsulation in a homogenous matrix. For the case of truncated pyramidal shaped InAs, Lc 10.8 nm when fully embedded in GaAs (ɛIP* = ɛOP* = - 0.072); 16.4 nm when the particle is grown on GaAs, but capped with InSb (ɛIP* = - 0.072 and ɛOP* =+0.065); and a maximum of 18.4 nm if capped with an alloy corresponding to ɛOP* =+0.037. The effect, which we term "3D Poisson-stabilization" provides a means to increase the epitaxial strain tolerance in epitaxial heterostructures by tailoring ɛOP*.

Thermo-mechanical Modelling of Pebble Beds in Fusion Blankets and its Implementation by a Return-Mapping Algorithm

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

Gan, Yixiang; Kamlah, Marc

In this investigation, a thermo-mechanical model of pebble beds is adopted and developed based on experiments by Dr. Reimann at Forschungszentrum Karlsruhe (FZK). The framework of the present material model is composed of a non-linear elastic law, the Drucker-Prager-Cap theory, and a modified creep law. Furthermore, the volumetric inelastic strain dependent thermal conductivity of beryllium pebble beds is taken into account and full thermo-mechanical coupling is considered. Investigation showed that the Drucker-Prager-Cap model implemented in ABAQUS can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importancemore » with respect to the application of pebble beds in fusion blankets. Therefore, UMAT (user defined material's mechanical behaviour) and UMATHT (user defined material's thermal behaviour) routines are used to re-implement the present thermo-mechanical model in ABAQUS. An elastic predictor radial return mapping algorithm is used to solve the non-associated plasticity iteratively, and a proper tangent stiffness matrix is obtained for cost-efficiency in the calculation. An explicit creep mechanism is adopted for the prediction of time-dependent behaviour in order to represent large creep strains in high temperature. Finally, the thermo-mechanical interactions are implemented in a UMATHT routine for the coupled analysis. The oedometric compression tests and creep tests of pebble beds at different temperatures are simulated with the help of the present UMAT and UMATHT routines, and the comparison between the simulation and the experiments is made. (authors)« less

Arroyo el Mimbral, Mexico, K/T unit: Origin as debris flow/turbidite, not a tsunami deposit

NASA Technical Reports Server (NTRS)

Bohor, Bruce F.; Betterton, William J.

1993-01-01

Coarse, spherule-bearing, elastic units have been discovered at 10 marine sites that span the K/T boundary in northeastern Mexico. We examined one of the best exposed sites in Arroyo el Mimbral, northwest of Tampico. The Mimbral outcrop displays a layered elastic unit up to 3 m thick enclosed by marly limestones of the Mendez (Latest Maastrichian) and Velasco (Earliest Danian) Formations. At its thickest point, this channelized elastic unit is comprised of 3 subunits: (1) a basal, poorly-sorted, ungraded calcareous spherule bed 1 m thick containing relict impact glass and shocked mineral grains, (2) a massive set of laminated calcite-cemented sandstones up to 2 m thick with plant debris at its base, (3) capped by a thin (up to 20 cm) set of rippled sandstone layers separated by silty mudstone drapes containing a small (921 pg/g) iridium anomaly. This tripartite elastic unit is conformably overlain by marls of the Velasco Formation. We also visited the La Lajilla site east of Ciudad Victoria; its stratigraphy is similar to Mimbral's, but its elastic beds are thinner and less extensive laterally. The Mimbral elastic unit has been interpreted previously as being deposited by a megawave or tsunami produced by an asteroid impact on nearby Yucatan (Chicxulub crater). However, a presumed 400-m paleodepth of water at the Mimbral site, channeling of the spherule subunit into the underlying Mendez Formation marls, and the overtopping of the basal, spherule-bearing subunit by the laminated sandstone subunit, all suggest a combined debris flow/turbidite origin for this elastic unit similar to that proposed for Upper Pleistocene sand/silt beds occurring elsewhere in the Gulf of Mexico. In this latter model, the sediment source region for the elastic unit is the lower continental shelf and slope escarpment. For the K/T unit at Mimbral, we propose that thick ejecta blanket deposits composed mostly of spherules were rapidly loaded onto the lower shelf and slope from an impact-generated ejecta curtain.

Induction of single- and double-strand breaks in plasmid DNA by monoenergetic alpha-particles with energies below the Bragg-maximum.

PubMed

Scholz, V; Weidner, J; Köhnlein, W; Frekers, D; Wörtche, H J

1997-01-01

The yield of single-strand breaks (ssb) and double-strand breaks (dsb) produced by alpha-particles at the end of their track in DNA-films was determined experimentally. Helium nuclei were accelerated to 600 keV in the 400 kV ion accelerator and scattered at a carbon target. The elastically scattered alpha-particles with energies of 344 keV and 485 keV were used to irradiate supercircular plasmid DNA in vacuo. For the dosimetry of the alpha-particles a surface barrier detector was used and the energy distribution of the alpha-particles determined. The energy loss of the particles in the DNA-layer was calculated. DNA samples were separated into the three conformational isomers using agarose gel electrophoresis. After fluorochromation the number of ssb and dsb per plasmid DNA molecule was established from the band intensities assuming the validity of Poisson statistics. Linear dose effect correlations were found for ssb and dsb per plasmid molecule. In the case of 344 keV-alpha-particles the yield of dsb was (8.6 +/- 0.9) x 10(-11) breaks/Gy x dalton. The ratio of ssb/dsb was 0.5 +/- 0.2. This is at least a factor of six larger than the ratio found in experiments with higher energy alpha-particles and from model calculations. Similar experiments with protons yielded a relative biological effectiveness (rbe) value of 2.8 for the induction of double-strand breaks by track end alpha-particles.

Modeling wear of cast Ti alloys.

PubMed

Chan, Kwai S; Koike, Marie; Okabe, Toru

2007-05-01

The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

Effects of viscosity and constraints on the dispersion and dissipation of waves in large blood vessels. I.

NASA Technical Reports Server (NTRS)

Jones, E.; Anliker, M.; Chang, I.

1971-01-01

Investigation of the effects of blood viscosity on dissipation as well as dispersion of small waves in arteries and veins by means of a parametric study. A linearized analysis of axisymmetric waves in a cylindrical membrane that contains a viscous fluid indicates that there are two families of waves: a family of slow waves and one of fast waves. The faster waves are shown to be more sensitive to variations in the elastic properties of the medium surrounding the blood vessels and at high values of the frequency parameter alpha. At low values of alpha the effects of viscosity on attenuation are reversed.

Comment on radiative magnetic energy shifts in hydrogen

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

Calmet, J.; Grotch, H.; Owen, D.A.

It is shown that the magnetic radiative energy shift derived from the relativistic-Lamb-shift expression of Erickson and Yennie reduces in the nonrelativistic limit to a formula given by Grotch and Hegstrom, which was derived starting from the nonrelativistic theory. This clears up a discrepancy between those two approaches. The corresponding correction to the g factor, which exists only for states with l not = 0, is estimated to be -0.24 ..cap alpha../sup 3/ for the 2P state of hydrogen.

A mass weighted chemical elastic network model elucidates closed form domain motions in proteins

PubMed Central

Kim, Min Hyeok; Seo, Sangjae; Jeong, Jay Il; Kim, Bum Joon; Liu, Wing Kam; Lim, Byeong Soo; Choi, Jae Boong; Kim, Moon Ki

2013-01-01

An elastic network model (ENM), usually Cα coarse-grained one, has been widely used to study protein dynamics as an alternative to classical molecular dynamics simulation. This simple approach dramatically saves the computational cost, but sometimes fails to describe a feasible conformational change due to unrealistically excessive spring connections. To overcome this limitation, we propose a mass-weighted chemical elastic network model (MWCENM) in which the total mass of each residue is assumed to be concentrated on the representative alpha carbon atom and various stiffness values are precisely assigned according to the types of chemical interactions. We test MWCENM on several well-known proteins of which both closed and open conformations are available as well as three α-helix rich proteins. Their normal mode analysis reveals that MWCENM not only generates more plausible conformational changes, especially for closed forms of proteins, but also preserves protein secondary structures thus distinguishing MWCENM from traditional ENMs. In addition, MWCENM also reduces computational burden by using a more sparse stiffness matrix. PMID:23456820

Adhesive Properties of Polyacrylate Gels

NASA Astrophysics Data System (ADS)

Flanigan, Cynthia; Shull, Kenneth

1998-03-01

Soft, low-modulus gels provide an interesting opportunity to examine small adhesive interactions between two bodies in contact. As shown through dynamic rheological studies, our materials undergo a rapid gelation as they are cooled from a viscous liquid at elevated temperatures to a soft, elastic solid at room temperature. At low temperatures, the gels exhibit a linearly elastic response and display moduli close to 100Pa, thereby forming materials with great potential for quantifying weak adhesive interactions with a variety of bodies ranging from polymer surfaces to biological entities. Our current studies focus on investigating interfacial effects by performing axisymmetric adhesion tests with a model polyacrylate gel formed by diluting the copolymer poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) to a 5-15 percent solution in 2-ethyl hexanol, a selective solvent for the midblock. We have explored two different experimental geometries including a hemispherical rigid indenter of glass pressed into a gel layer of varying thicknesses, and a soft, gel cap in contact with a rigid polymer surface. By simultaneously measuring the applied load, displacement between the two bodies, and contact area during loading cycles, we are able to employ a linearly elastic fracture mechanics analysis to obtain estimates of the gel's modulus over a range of polymer concentrations, and G, the energy release rate.

Noninvasive Vascular Displacement Estimation for Relative Elastic Modulus Reconstruction in Transversal Imaging Planes

PubMed Central

Hansen, Hendrik H.G.; Richards, Michael S.; Doyley, Marvin M.; de Korte, Chris L.

2013-01-01

Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF) data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding. PMID:23478602

Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme A

NASA Technical Reports Server (NTRS)

Miller, S. L.; Schlesinger, G.

1993-01-01

Pantoic acid can by synthesized in good prebiotic yield from isobutyraldehyde or alpha-ketoisovaleric acid + H2CO + HCN. Isobutyraldehyde is the Strecker precursor to valine and alpha-ketoisovaleric acid is the valine transamination product. Mg2+ and Ca2+ as well as several transition metals are catalysts for the alpha-ketoisovaleric acid reaction. Pantothenic acid is produced from pantoyl lactone (easily formed from pantoic acid) and the relatively high concentrations of beta-alanine that would be formed on drying prebiotic amino acid mixtures. There is no selectivity for this reaction over glycine, alanine, or gamma-amino butyric acid. The components of coenzyme A are discussed in terms of ease of prebiotic formation and stability and are shown to be plausible choices, but many other compounds are possible. The gamma-OH of pantoic acid needs to be capped to prevent decomposition of pantothenic acid. These results suggest that coenzyme A function was important in the earliest metabolic pathways and that the coenzyme A precursor contained most of the components of the present coenzyme.

Origin of ice-rafted debris: Pleistocene paleoceanography in the western Arctic Ocean

NASA Astrophysics Data System (ADS)

Bischof, Jens; Clark, David L.; Vincent, Jean-Serge

1996-12-01

The composition of Pleistocene ice-rafted debris (IRD) >250 µm was analyzed quantitatively by grain counting in five sediment cores from the western central Arctic Ocean and compared with the composition of till clasts from NW Canada in order to determine the dropstone origin and to reconstruct the Pleistocene ice driftways and surface currents. The IRD composition alternates repeatedly between carbonate- and quartz-dominated assemblages, along with metamorphic and igneous rocks, clastic rocks, and some chert. The highest quartz content is found on the Alpha Ridge, while carbonate percentages are highest on the Northwind Ridge (NWR) and the Chukchi Cap. The source for the carbonates is the area around Banks and Victoria Islands and parts of northern Canada. Quartz most likely originated from the central Queen Elizabeth Islands. IRD on the southeastern Alpha Ridge is dominated by mafic crystalline rocks from northern Ellesmere Island and northern Greenland. At least six major glacial intervals are identified within the last 1 million years, during which icebergs drifted toward the west in the Beaufort Sea, straight northward in the central Arctic Ocean, and northeastward on the SE Alpha Ridge.

Vulnerable Atherosclerotic Plaque Elasticity Reconstruction Based on a Segmentation-Driven Optimization Procedure Using Strain Measurements: Theoretical Framework

PubMed Central

Le Floc’h, Simon; Tracqui, Philippe; Finet, Gérard; Gharib, Ahmed M.; Maurice, Roch L.; Cloutier, Guy; Pettigrew, Roderic I.

2016-01-01

It is now recognized that prediction of the vulnerable coronary plaque rupture requires not only an accurate quantification of fibrous cap thickness and necrotic core morphology but also a precise knowledge of the mechanical properties of plaque components. Indeed, such knowledge would allow a precise evaluation of the peak cap-stress amplitude, which is known to be a good biomechanical predictor of plaque rupture. Several studies have been performed to reconstruct a Young’s modulus map from strain elastograms. It seems that the main issue for improving such methods does not rely on the optimization algorithm itself, but rather on preconditioning requiring the best estimation of the plaque components’ contours. The present theoretical study was therefore designed to develop: 1) a preconditioning model to extract the plaque morphology in order to initiate the optimization process, and 2) an approach combining a dynamic segmentation method with an optimization procedure to highlight the modulogram of the atherosclerotic plaque. This methodology, based on the continuum mechanics theory prescribing the strain field, was successfully applied to seven intravascular ultrasound coronary lesion morphologies. The reconstructed cap thickness, necrotic core area, calcium area, and the Young’s moduli of the calcium, necrotic core, and fibrosis were obtained with mean relative errors of 12%, 4% and 1%, 43%, 32%, and 2%, respectively. PMID:19164080

Regulation of nicotinic acetylcholine receptor phosphorylation in rat myotubes by forskolin and cAMP

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

Miles, K.; Anthony, D.T.; Rubin, L.L.

1987-09-01

The nicotinic acetylcholine receptor (Ac-ChoR) from rat myotubes prelabeled in culture with (/sup 32/P)orthophosphate was isolated by acetylcholine affinity chromatography followed by immunoaffinity chromatography. Under basal conditions, the nicotinic AcChoR was shown to be phosphorylated in situ on the ..beta.. and delta subunits. Regulation of AcChoR phosphorylation by cAMP-dependent protein kinase was explored by the addition of forskolin or cAMP analogues to prelabeled cell cultures. Forskolin, an activator of adenylate cyclase, stimulated the phosphorylation of the delta subunit 20-fold over basal phosphorylation and induced phosphorylation of the ..cap alpha.. subunit. The effect of forskolin was dose dependent with a half-maximalmore » response at 8 ..mu..M in the presence of 35 ..mu..M Ro 20-1724, a phosphodiesterase inhibitor. Stimulation of delta subunit phosphorylation was almost maximal within 5 min, whereas stimulation of ..cap alpha.. subunit phosphorylation was not maximal until 45 min after forskolin treatment. Stimulation of AcChoR phosphorylation by 8-benzylthioadenosine 3',5'-cyclic monophosphate was identical to that obtained by forskolin. Two-dimensional thermolytic phosphopeptide maps of the delta subunit revealed a single major phosphopeptide. These results correlate closely with the observed effects of forskolin on AcChoR desensitization in muscle and suggest that cAMP-dependent phosphorylation of the delta subunit increases the rate of AcChoR desensitization in rat myotubes.« less

The 3D model: explaining densification and deformation mechanisms by using 3D parameter plots.

PubMed

Picker, Katharina M

2004-04-01

The aim of the study was to analyze very differently deforming materials using 3D parameter plots and consequently to gain deeper insights into the densification and deformation process described with the 3D model in order to define an ideal tableting excipient. The excipients used were dicalcium phosphate dihydrate (DCPD), sodium chloride (NaCl), microcrystalline cellulose (MCC), xylitol, mannitol, alpha-lactose monohydrate, maltose, hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (NaCMC), cellulose acetate (CAC), maize starch, potato starch, pregelatinized starch, and maltodextrine. All of the materials were tableted to graded maximum relative densities (rhorel, max) using an eccentric tableting machine. The data which resulted, namely force, displacement, and time, were analyzed by the application of 3D modeling. Different particle size fractions of DCPD, CAC, and MCC were analyzed in addition. Brittle deforming materials such as DCPD exhibited a completely different 3D parameter plot, with low time plasticity, d, and low pressure plasticity, e, and a strong decrease in omega values when densification increased, in contrast to the plastically deforming MCC, which had much higher d, e, and omega values. e and omega values changed only slightly when densification increased for MCC. NaCl showed less of a decrease in omega values than DCPD did, and the d and e values were between those of MCC and DCPD. The sugar alcohols, xylitol and mannitol, behaved in a similar fashion to sodium chloride. This is also valid for the crystalline sugars, alpha-lactose monohydrate, and maltose. However, the sugars are more brittle than the sugar alcohols. The cellulose derivatives, HPMC, NaCMC, and CAC, are as plastic as MCC, however, their elasticity depends on substitution indicated by lower (more elastic) or higher (less elastic) omega values. The native starches, maize starch and potato starch, are very elastic, and pregelatinized starch and maltodextrine are less elastic and exhibited higher omega values. Deformation behavior as shown in 3D parameter plots depends on particle size for polymers such as CAC and MCC; however, it does not depend on particle size for brittle materials such as DCPD. An ideally deforming tableting excipient should exhibit high e, d, and omega values with a constant ratio of e and omega at increasing densification.

Casein phosphopeptide-amorphous calcium phosphate remineralization of primary teeth early enamel lesions.

PubMed

Zhou, Chunhua; Zhang, Dongliang; Bai, Yuxing; Li, Song

2014-01-01

Early childhood caries (ECC) is a serious problem that progresses rapidly and often goes untreated. Current traumatic treatments may be replaced by safe and effective remineralization at very early stages. The aim of this in vitro study was to evaluate the remineralization effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste on enamel lesions by assessing ultrastructure, nanomechanical properties, and compound and elemental analysis. Enamel specimens from 6-year-old children were divided into groups: (1) native enamel; (2) water as negative control; (3) 500ppm NaF as positive control; and (4-7) CPP-ACP paste for 4, 8, 12, and 24h, as test groups. Ultrastructure and roughness were observed by atomic force microscopy (AFM); nanohardness and elastic modulus were measured by nanoindentation; compound and crystal size of enamel surface patterns were investigated by X-ray diffractometer (XRD). An electron microprobe (EPMA) was used for element analysis. Data were analyzed using one-way ANOVA. The CPP-ACP paste repaired the microstructure of enamel, including prism and interprism, through significantly increased hydroxyapatite crystal size (12.06±0.21nm) and Ca/P molar ratios (1.637±0.096) as compared with NaF (8.56±0.13nm crystal size and 1.397±0.086 Ca/P, p<0.01). Both CPP-ACP and NaF decrease roughness, and increase the nanohardness and elastic modulus, with no significant differences between the materials. The CPP-ACP paste is more suitable for children than NaF, due to advantages for remineralization. The AFM, nanoindentation, EPMA, and XRD are very helpful methods for further understanding of microscale and nanoscale remineralization mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Low elastic modulus Ti-Ta alloys for load-bearing permanent implants: enhancing the biodegradation resistance by electrochemical surface engineering.

PubMed

Kesteven, Jazmin; Kannan, M Bobby; Walter, Rhys; Khakbaz, Hadis; Choe, Han-Choel

2015-01-01

In this study, the in vitro degradation behaviour of titanium-tantalum (Ti-Ta) alloys (10-30 wt.% Ta) was investigated and compared with conventional implant materials, i.e., commercially pure titanium (Cp-Ti) and titanium-aluminium-vanadium (Ti6Al4V) alloy. Among the three Ti-Ta alloys studied, the Ti20Ta (6.3×10(-4) mm/y) exhibited the lowest degradation rate, followed by Ti30Ta (1.2×10(-3) mm/y) and Ti10Ta (1.4×10(-3) mm/y). All the Ti-Ta alloys exhibited lower degradation rate than that of Cp-Ti (1.8×10(-3) mm/y), which suggests that Ta addition to Ti is beneficial. As compared to Ti6Al4V alloy (8.1×10(-4) mm/y), the degradation rate of Ti20Ta alloy was lower by ~22%. However, the Ti30Ta alloy, which has closer elastic modulus to that of natural bone, showed ~48% higher degradation rate than that of Ti6Al4V alloy. Hence, to improve the degradation performance of Ti30Ta alloy, an intermediate thin porous layer was formed electrochemically on the alloy followed by calcium phosphate (CaP) electrodeposition. The coated Ti30Ta alloy (3.8×10(-3) mm/y) showed ~53% lower degradation rate than that of Ti6Al4V alloy. Thus, the study suggests that CaP coated Ti30Ta alloy can be a viable material for load-bearing permanent implants. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a Knowledge Base of Ti-Alloys From First-Principles and Thermodynamic Modeling

NASA Astrophysics Data System (ADS)

Marker, Cassie

An aging population with an active lifestyle requires the development of better load-bearing implants, which have high levels of biocompatibility and a low elastic modulus. Titanium alloys, in the body centered cubic phase, are great implant candidates, due to their mechanical properties and biocompatibility. The present work aims at investigating the thermodynamic and elastic properties of bcc Tialloys, using the integrated first-principles based on Density Functional Theory (DFT) and the CALculation of PHAse Diagrams (CALPHAD) method. The use of integrated first-principles calculations based on DFT and CALPHAD modeling has greatly reduced the need for trial and error metallurgy, which is ineffective and costly. The phase stability of Ti-alloys has been shown to greatly affect their elastic properties. Traditionally, CALPHAD modeling has been used to predict the equilibrium phase formation, but in the case of Ti-alloys, predicting the formation of two metastable phases o and alpha" is of great importance as these phases also drastically effect the elastic properties. To build a knowledge base of Ti-alloys, for biomedical load-bearing implants, the Ti-Mo-Nb-Sn-Ta-Zr system was studied because of the biocompatibility and the bcc stabilizing effects of some of the elements. With the focus on bcc Ti-rich alloys, a database of thermodynamic descriptions of each phase for the pure elements, binary and Ti-rich ternary alloys was developed in the present work. Previous thermodynamic descriptions for the pure elements were adopted from the widely used SGTE database for global compatibility. The previous binary and ternary models from the literature were evaluated for accuracy and new thermodynamic descriptions were developed when necessary. The models were evaluated using available experimental data, as well as the enthalpy of formation of the bcc phase obtained from first-principles calculations based on DFT. The thermodynamic descriptions were combined into a database ensuring that the sublattice models are compatible with each other. For subsystems, such as the Sn-Ta system, where no thermodynamic description had been evaluated and minimal experimental data was available, first-principles calculations based on DFT were used. The Sn-Ta system has two intermetallic phases, TaSn2 and Ta3Sn, with three solution phases: bcc, body centered tetragonal (bct) and diamond. First-principles calculations were completed on the intermetallic and solution phases. Special quasirandom structures (SQS) were used to obtain information about the solution phases across the entire composition range. The Debye-Gruneisen approach, as well as the quasiharmonic phonon method, were used to obtain the finite-temperature data. Results from the first-principles calculations and experiments were used to complete the thermodynamic description. The resulting phase diagram reproduced the first-principles calculations and experimental data accurately. In order to determine the effect of alloying on the elastic properties, first-principles calculations based on DFT were systematically done on the pure elements, five Ti-X binary systems and Ti-X-Y ternary systems (X ≠ Y = Mo, Nb, Sn, Ta Zr) in the bcc phase. The first-principles calculations predicted the single crystal elastic stiffness constants cij 's. Correspondingly, the polycrystalline aggregate properties were also estimated from the cij's, including bulk modulus B, shear modulus G and Young's modulus E. The calculated results showed good agreement with experimental results. The CALPHAD method was then adapted to assist in the database development of the elastic properties as a function of composition. On average, the database predicted the elastic properties of higher order Ti-alloys within 5 GPa of the experimental results. Finally, the formation of the metastable phases, o and alpha" was studied in the Ti-Ta and Ti-Nb systems. The formation energy of these phases, calculated from first-principles at 0 K, showed that the phases have similar formation energies to the bcc and hcp phases. Inelastic neutron scattering was completed on four different Ti-Nb compositions to study the entropy of the phases as well as the transformations occurring when the phases form and the phase fractions. Ongoing work is being done to use the experimental information to introduce thermodynamic descriptions for these two phases in the Ti-Nb system in order to be able to predict the formation and phase fractions. DFT based first-principles were used to predict the effect these phases have on the elastic properties and a rule of mixtures was used to determine the elastic properties of multi-phase alloys. The results were compared with experiments and showed that if the ongoing modeling can predict the phase fraction, the elastic database can accurately predict the elastic properties of the o and alpha" phases. This thesis provides a knowledge base of the thermodynamic and elastic properties of Ti-alloys from computational thermodynamics. The databases created will impact research activities on Ti-alloys and specifically efforts focused on Ti-alloys for biomedical applications.

On the role of the transformation eigenstrain in the growth or shrinkage of spheroidal isotropic precipitations

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

Fischer, F.D.; Boehm, H.J.

The jumps of the strain and stress tensors on the surface of elastic homogeneous or inhomogeneous ellipsoidal inclusions embedded in an elastic matrix are obtained from results reported in the literature. They are used to derive closed-form expressions for the thermodynamic force in such matrix-inclusion systems that are subjected to a generally defined homogeneous transformation eigenstrain. A detailed study is presented for an isotropic spheroidal inclusion in an isotropic matrix in which the most important parameters are the inclusion's aspect ratio {alpha} and an eigenstrain triaxiality parameter d-bar. The fluctuations of the thermodynamic force are investigated for a set ofmore » specific transformation eigenstrain tensors and are presented for inclusion shapes ranging from disk-like to fiber-like spheroids.« less

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

Schwarz, R.B.; Bach, H.T.; Harms, U.

We used a resonant-ultrasound-spectroscopy technique to measure the three independent elastic constants of PdH{sub x}, PdD{sub x}, and PdT{sub x} single crystals at 300 K. For 0.1x0.62 our PdH{sub x} crystals are two-phase mixtures of coherent {alpha} and {beta} hydride phases. For increasing x in this range, C{sub 44} decreases monotonically whereas C'=12(C11-C12) has a concave parabolic dependence. This difference is because C' is softened by an anelastic relaxation resulting from acoustic-stress-induced changes in the shape of the coherent lenticular-shape precipitates ({beta}-hydride precipitates in {alpha}-hydride matrix and {alpha}-hydride precipitates in {beta}-hydride matrix). In the {beta}-phase C' and C{sub 44} decreasemore » with increasing hydrogen (or deuterium or tritium) content. Furthermore, C' exhibits a strong isotope effect whereas C{sub 44} does not. This effect is attributed to differences in the excitation of optical phonons in Pd-H, Pd-D and Pd-T.« less

Occurrence of rhombic prisms in some structures

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

Nyman, H.

1976-02-01

An ideal rhombic prism is defined as two regular trigonal prisms sharing a square face. In terms of such rhombic prisms, the structures of CrB and ..cap alpha..-PdCl/sub 2/, U/sub 3/Si/sub 2/ and Au/sub 3/Zn, and CoCa/sub 3/ and PdS are easily described. A network of rhombic prisms, with cubic symmetry, is also used to describe the structures of CoAs/sub 3/, Sc(OH)/sub 3/, WAl/sub 12/, and NaMn/sub 7/O/sub 12/.

In vitro histamine H/sub 2/-antagonist activity of the novel compound HUK 978

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

Coombes, J.D.; Norris, D.B.; Rising, T.J.

1985-11-04

Histamine stimulated adenylate cyclase from guinea-pig fundic mucosa and /sup 3/H-tiotidine binding in guinea-pig cerebral cortex were used to assess the in-vitro histamine H/sub 2/-activity of the novel H/sub 2/-antagonist HUK 978. The results showed that HUK 978 was a more potent H/sub 2/-antagonist than either cimetidine or ranitidine. HUK 978 was also shown to be devoid of activity at the histamine H-/sub 1/-receptor, the muscarinic receptor and the ..cap alpha.. and ..beta..-adrenergic receptors.

Multiphysics phase field modeling of hydrogen diffusion and delta-hydride precipitation in alpha-zirconium

NASA Astrophysics Data System (ADS)

Jokisaari, Andrea M.

Hydride precipitation in zirconium is a significant factor limiting the lifetime of nuclear fuel cladding, because hydride microstructures play a key role in the degradation of fuel cladding. However, the behavior of hydrogen in zirconium has typically been modeled using mean field approaches, which do not consider microstructural evolution. This thesis describes a quantitative microstructural evolution model for the alpha-zirconium/delta-hydride system and the associated numerical methods and algorithms that were developed. The multiphysics, phase field-based model incorporates CALPHAD free energy descriptions, linear elastic solid mechanics, and classical nucleation theory. A flexible simulation software implementing the model, Hyrax, is built on the Multiphysics Object Oriented Simulation Environment (MOOSE) finite element framework. Hyrax is open-source and freely available; moreover, the numerical methods and algorithms that have been developed are generalizable to other systems. The algorithms are described in detail, and verification studies for each are discussed. In addition, analyses of the sensitivity of the simulation results to the choice of numerical parameters are presented. For example, threshold values for the CALPHAD free energy algorithm and the use of mesh and time adaptivity when employing the nucleation algorithm are studied. Furthermore, preliminary insights into the nucleation behavior of delta-hydrides are described. These include a) the sensitivities of the nucleation rate to temperature, interfacial energy, composition and elastic energy, b) the spatial variation of the nucleation rate around a single precipitate, and c) the effect of interfacial energy and nucleation rate on the precipitate microstructure. Finally, several avenues for future work are discussed. Topics encompass the terminal solid solubility hysteresis of hydrogen in zirconium and the effects of the alpha/delta interfacial energy, as well as thermodiffusion, plasticity, and irradiation, which are not yet accounted for in the model.

[Cytochemical localization and properties of selected nucleolytic enzymes].

PubMed

Sierakowska, Halina

2015-01-01

In the article there are shortly outlined studies on cytochemical localization of selected nucleolytic enzymes carried out between 1957-1986 by David Shugar and his coworkers. The histochemical localization of several nucleolytic enzymes in animal and plant tissues was determined by synthesis of specific substrates, alpha-naphthyl esters of 5'- and 3'-nucleotides and their derivatives. In rat tissues phosphodiesterase I was localized in the plasma membrane whereas phosphodiesterase II in the lizosomes, reflecting their physiological roles. The localization of pancreatic type ribonuclease in animal tissues was determined, indicating its role in extracellular digestion. Plant nucleotide pyrophosphatase was localized in several tissues, purified to near homogeneity from potato tubers and its properties and substrate specificity were determined. Application of this enzyme for removal of m7GMP from the "cap" of eukaryotic mRNA allowed to elucidate the role of "cap" in mRNA binding to ribosomes in the process of translation. Furthermore, cyclic nucleotide phosphodiesterase was isolated from potato tubers and its physicochemical properties, oligomeric structure and substrate specificity were elucidated.

Optimized Design and Synthesis of Cell Permeable Biarsenical Cyanine Probe for Imaging Tagged Cytosolic Bacterial Proteins

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

Fu, Na; Xiong, Yijia; Squier, Thomas C.

2013-01-21

To optimize cellular delivery and specific labeling of tagged cytosolic proteins by biarsenical fluorescent probes build around a cyanine dye scaffold, we have systematically varied the polarity of the hydrophobic tails (i.e., 4-5 methylene groups appended by a sulfonate or methoxy ester moiety) and arsenic capping reagent (ethanedithiol versus benzenedithiol). Targeted labeling of the cytosolic proteins SlyD and the alpha subunit of RNA polymerase engineered with a tetracysteine tagging sequences demonstrate the utility of the newly synthesized probes for live-cell visualization, albeit with varying efficiencies and background intensities. Optimal routine labeling and visualization is apparent using the ethanedithiol capping reagentmore » with the uncharged methoxy ester functionalized acyl chains. These measurements demonstrate the general utility of this class of photostable and highly fluorescent biarsenical reagents based on the cyanine scaffold for in vivo targeting of tagged cellular proteins for live cell measurements of protein dynamics.« less

Proteomic Profile of Unstable Atheroma Plaque: Increased Neutrophil Defensin 1, Clusterin, and Apolipoprotein E Levels in Carotid Secretome.

PubMed

Aragonès, Gemma; Auguet, Teresa; Guiu-Jurado, Esther; Berlanga, Alba; Curriu, Marta; Martinez, Salomé; Alibalic, Ajla; Aguilar, Carmen; Hernández, Esteban; Camara, María-Luisa; Canela, Núria; Herrero, Pol; Ruyra, Xavier; Martín-Paredero, Vicente; Richart, Cristóbal

2016-03-04

Because of the clinical significance of carotid atherosclerosis, the search for novel biomarkers has become a priority. The aim of the present study was to compare the protein secretion profile of the carotid atherosclerotic plaque (CAP, n = 12) and nonatherosclerotic mammary artery (MA, n = 10) secretomes. We used a nontargeted proteomic approach that incorporated tandem immunoaffinity depletion, iTRAQ labeling, and nanoflow liquid chromatography coupled to high-resolution mass spectrometry. In total, 162 proteins were quantified, of which 25 showed statistically significant differences in secretome levels between carotid atherosclerotic plaque and nondiseased mammary artery. We found increased levels of neutrophil defensin 1, apolipoprotein E, clusterin, and zinc-alpha-2-glycoprotein in CAP secretomes. Results were validated by ELISA assays. Also, differentially secreted proteins are involved in pathways such as focal adhesion and leukocyte transendothelial migration. In conclusion, this study provides a subset of identified proteins that are differently expressed in secretomes of clinical significance.

Skylab sleep monitoring experiment (experiment M133)

NASA Technical Reports Server (NTRS)

Frost, J. D., Jr.

1975-01-01

A summary of the conceptual design of the Skylab sleep monitoring experiment and a comprehensive compilation of the data-analysis results from the three Skylab missions is presented. One astronaut was studied per flight, electroencephalographic, electro-oculographic, and headmotion signals acquired during sleep by use of an elastic recording cap containing sponge electrodes and an attached miniature preamplifier/accelerometer unit are shown. A control-panel assembly, mounted in the sleep compartment, tested electrodes, preserved analog signals, and automatically analyzed data in real time (providing a telemetered indication of sleep stage). Results indicate that men are able to obtain adequate sleep in regularly scheduled eight-hour rest periods during extended space missions.

Hybrid biocomposites based on titania nanotubes and a hydroxyapatite coating deposited by RF-magnetron sputtering: Surface topography, structure, and mechanical properties

NASA Astrophysics Data System (ADS)

Chernozem, Roman V.; Surmeneva, Maria A.; Krause, Bärbel; Baumbach, Tilo; Ignatov, Viktor P.; Tyurin, Alexander I.; Loza, Kateryna; Epple, Matthias; Surmenev, Roman A.

2017-12-01

In this study, biocomposites based on porous titanium oxide structures and a calcium phosphate (CaP) or hydroxyapatite (HA) coating are described and prepared. Nanotubes (NTs) with different pore dimensions were processed using anodic oxidation of Ti substrates in a NH4F-containing electrolyte solution at anodization voltages of 30 and 60 V with a DC power supply. The external diameters of the nanotubes prepared at 30 V and 60 V were 53 ± 10 and 98 ± 16 nm, respectively. RF-magnetron sputtering of the HA target in a single deposition run was performed to prepare a coating on the surface of TiO2 NTs prepared at 30 and 60 V. The thickness of the CaP coating deposited on the mirror-polished Si substrate in the same deposition run with TiO2 NTs was determined by optical ellipsometry (SE) 95 ± 5 nm. Uncoated and CaP-coated NTs were annealed at 500 °C in air. Afterwards, the presence of TiO2 (anatase) was observed. The scanning electron microscopy (SEM), X-ray diffraction (XRD), photoelectron spectroscopy (XPS) and nanoindentation results revealed the influence that the NT dimensions had on the CaP coating deposition process. The tubular surfaces of the NTs were completely coated with the HA coating when prepared at 30 V, and no homogeneous CaP coating was observed when prepared at 60 V. The XRD patterns show peaks assigned to crystalline HA only for the coated TiO2 NTs prepared at 30 V. High-resolution XPS spectra show binding energies (BE) of Ca 2p, P 2p and O 1s core-levels corresponding to HA and amorphous calcium phosphate on TiO2 NTs prepared at 30 V and 60 V, respectively. Fabrication of TiO2 NTs results in a significant decrease to the elastic modulus and nanohardness compared to the Ti substrate. The porous structure of the NTs causes an increase in the elastic strain to failure of the coating (H/E) and the parameter used to describe the resistance of the material to plastic deformation (H3/E2) at the nanoscale level compared to the Ti substrate. Furthermore, only the HA coating on the NTs exhibits a significantly increased H/E ratio and H3/E2 factor compared to the NTs and Ti substrate. Increases in resistance to penetration for the indenter were also observed for HA-coated TiO2 NTs prepared at 30 V compared to uncoated and CaP-coated NTs prepared at 60 V.

An Unusual Hydrophobic Core Confers Extreme Flexibility to HEAT Repeat Proteins

PubMed Central

Kappel, Christian; Zachariae, Ulrich; Dölker, Nicole; Grubmüller, Helmut

2010-01-01

Alpha-solenoid proteins are suggested to constitute highly flexible macromolecules, whose structural variability and large surface area is instrumental in many important protein-protein binding processes. By equilibrium and nonequilibrium molecular dynamics simulations, we show that importin-β, an archetypical α-solenoid, displays unprecedentedly large and fully reversible elasticity. Our stretching molecular dynamics simulations reveal full elasticity over up to twofold end-to-end extensions compared to its bound state. Despite the absence of any long-range intramolecular contacts, the protein can return to its equilibrium structure to within 3 Å backbone RMSD after the release of mechanical stress. We find that this extreme degree of flexibility is based on an unusually flexible hydrophobic core that differs substantially from that of structurally similar but more rigid globular proteins. In that respect, the core of importin-β resembles molten globules. The elastic behavior is dominated by nonpolar interactions between HEAT repeats, combined with conformational entropic effects. Our results suggest that α-solenoid structures such as importin-β may bridge the molecular gap between completely structured and intrinsically disordered proteins. PMID:20816072

Polynomial Expressions for Estimating Elastic Constants From the Resonance of Circular Plates

NASA Technical Reports Server (NTRS)

Salem, Jonathan A.; Singh, Abhishek

2005-01-01

Two approaches were taken to make convenient spread sheet calculations of elastic constants from resonance data and the tables in ASTM C1259 and E1876: polynomials were fit to the tables; and an automated spread sheet interpolation routine was generated. To compare the approaches, the resonant frequencies of circular plates made of glass, hardened maraging steel, alpha silicon carbide, silicon nitride, tungsten carbide, tape cast NiO-YSZ, and zinc selenide were measured. The elastic constants, as calculated via the polynomials and linear interpolation of the tabular data in ASTM C1259 and E1876, were found comparable for engineering purposes, with the differences typically being less than 0.5 percent. Calculation of additional v values at t/R between 0 and 0.2 would allow better curve fits. This is not necessary for common engineering purposes, however, it might benefit the testing of emerging thin structures such as fuel cell electrolytes, gas conversion membranes, and coatings when Poisson s ratio is less than 0.15 and high precision is needed.

Detection of rupture-prone atherosclerotic plaques by time-resolved laser-induced fluorescence spectroscopy.

PubMed

Marcu, Laura; Jo, Javier A; Fang, Qiyin; Papaioannou, Thanassis; Reil, Todd; Qiao, Jian-Hua; Baker, J Dennis; Freischlag, Julie A; Fishbein, Michael C

2009-05-01

Plaque with dense inflammatory cells, including macrophages, thin fibrous cap and superficial necrotic/lipid core is thought to be prone-to-rupture. We report a time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) technique for detection of such markers of plaque vulnerability in human plaques. The autofluorescence of carotid plaques (65 endarterectomy patients) induced by a pulsed laser (337 nm, 0.7 ns) was measured from 831 distinct areas. The emission was resolved spectrally (360-550 nm range) and temporally (0.3 ns resolution) using a prototype fiber-optic TR-LIFS apparatus. Lesions were evaluated microscopically and quantified as to the % of different components (fibrous cap, necrotic core, inflammatory cells, foam cells, mature and degraded collagen, elastic fibers, calcification, and smooth muscle cell of the vessel wall). We determined that the spectral intensities and time-dependent parameters at discrete emission wavelengths (1) allow for discrimination (sensitivity >81%, specificity >94%) of various compositional and pathological features associated with plaque vulnerability including infiltration of macrophages into intima and necrotic/lipid core under a thin fibrous cap, and (2) show a linear correlation with plaque biochemical content: elastin (P<0.008), collagen (P<0.02), inflammatory cells (P<0.003), necrosis (P<0.004). Our results demonstrate the feasibility of TR-LIFS as a method for the identification of markers of plaque vulnerability. Current findings enable future development of TR-LIFS-based clinical devices for rapid investigation of atherosclerotic plaques and detection of those at high-risk.

Radiation effects in accelerator components

NASA Astrophysics Data System (ADS)

Borden, M. J.

1995-05-01

A review of basic radiation effects is presented. The fundamental definitions of radioactivity are given for alpha, beta, positron decay, gamma-ray emission and electron capture. The interaction of neutrons with material is covered including: absorption through radiative capture, neutron-proton interaction, alpha particle emission, neutron-multi-neutron reactions and fission. Basic equations defining inelastic and elastic scattering are presented with examples of neutron energy loss per collision for several elements. Photon interactions are considered for gamma-rays and x-rays. Photoelectric collisions, the Compton effect and pair production are reviewed. Electron-proton interactions are discussed with emphasis placed on defect production. Basic displacement damage mechanisms for photon and particle interaction are presented. Several examples of radiation effects to plastics, electronics and ceramics are presented. Extended references are given for each example.

Modeling and Studying the Effect of Texture and Elastic Anisotropy of Copper Microstructure in Nanoscale Interconnects on Reliability in Integrated Circuits

NASA Astrophysics Data System (ADS)

Basavalingappa, Adarsh

Copper interconnects are typically polycrystalline and follow a lognormal grain size distribution. Polycrystalline copper interconnect microstructures with a lognormal grain size distribution were obtained with a Voronoi tessellation approach. The interconnect structures thus obtained were used to study grain growth mechanisms, grain boundary scattering, scattering dependent resistance of interconnects, stress evolution, vacancy migration, reliability life times, impact of orientation dependent anisotropy on various mechanisms, etc. In this work, the microstructures were used to study the impact of microstructure and elastic anisotropy of copper on thermal and electromigration induced failure. A test structure with copper and bulk moduli values was modeled to do a comparative study with the test structures with textured microstructure and elastic anisotropy. By subjecting the modeled test structure to a thermal stress by ramping temperature down from 400 °C to 100 °C, a significant variation in normal stresses and pressure were observed at the grain boundaries. This variation in normal stresses and hydrostatic stresses at the grain boundaries was found to be dependent on the orientation, dimensions, surroundings, and location of the grains. This may introduce new weak points within the metal line where normal stresses can be very high depending on the orientation of the grains leading to delamination and accumulation sites for vacancies. Further, the hydrostatic stress gradients act as a driving force for vacancy migration. The normal stresses can exceed certain grain orientation dependent critical threshold values and induce delamination at the copper and cap material interface, thereby leading to void nucleation and growth. Modeled test structures were subjected to a series of copper depositions at 250 °C followed by copper etch at 25 °C to obtain initial stress conditions. Then the modeled test structures were subjected to 100,000 hours ( 11.4 years) of simulated thermal stress at an elevated temperature of 150 °C. Vacancy migration due to concentration gradients, thermal gradients, and mechanical stress gradients were considered under the applied thermal stress. As a result, relatively high concentrations of vacancies were observed in the test structure due to a driving force caused by the pressure gradients resulting from the elastic anisotropy of copper. The grain growth mechanism was not considered in these simulations. Studies with two grain analysis demonstrated that the stress gradients developed will be severe when (100) grains are adjacent to (111) grains, therefore making them the weak points for potentially reliability failures. Ilan Blech discovered that electromigration occurs above a critical product of the current density and metal length, commonly referred as Blech condition. Electromigration stress simulations in this work were carried out by subjecting test structures to scaled current densities to overcome the Blech condition of (jL)crit for small dimensions of test structure and the low temperature stress condition used. Vacancy migration under the electromigration stress conditions was considered along with the vacancy migration induced stress evolution. A simple void growth model was used which assumes voids start to form when vacancies reach a critical level. Increase of vacancies in a localized region increases the resistance of the metal line. Considering a 10% increase in resistance as a failure criterion, the distributions of failure times were obtained for given electromigration stress conditions. Bimodal/multimodal failure distributions were obtained as a result. The sigma values were slightly lower than the ones commonly observed from experiments. The anisotropy of the elastic moduli of copper leads to the development of significantly different stress values which are dependent on the orientation of the grains. This results in some grains having higher normal stress than the others. This grain orientation dependent normal stress can reach a critical stress necessary to induce delamination at the copper and cap interface. Time taken to reach critical stress was considered as time to fail and distributions of failure times were obtained for structures with different grain orientations in the microstructure for different critical stress values. The sigma values of the failure distributions thus obtained for different constant critical stress values had a strong dependence of on the critical stress. It is therefore critical to use the appropriate critical stress value for the delamination of copper and cap interface. The critical stress necessary to overcome the local adhesion of the copper and the cap material interface is dependent on grain orientation of the copper. Simulations were carried out by considering grain orientation dependent critical normal stress values as failure criteria. The sigma value thus obtained with selected critical stress values were comparable to sigma values commonly observed from experiments.

Apoptosis of vascular smooth muscle cells induces features of plaque vulnerability in atherosclerosis.

PubMed

Clarke, Murray C H; Figg, Nichola; Maguire, Janet J; Davenport, Anthony P; Goddard, Martin; Littlewood, Trevor D; Bennett, Martin R

2006-09-01

Vascular smooth muscle cell (VSMC) apoptosis occurs in many arterial diseases, including aneurysm formation, angioplasty restenosis and atherosclerosis. Although VSMC apoptosis promotes vessel remodeling, coagulation and inflammation, its precise contribution to these diseases is unknown, given that apoptosis frequently accompanies vessel injury or alterations to flow. To study the direct consequences of VSMC apoptosis, we generated transgenic mice expressing the human diphtheria toxin receptor (hDTR, encoded by HBEGF) from a minimal Tagln (also known as SM22alpha) promoter. Despite apoptosis inducing loss of 50-70% of VSMCs, normal arteries showed no inflammation, reactive proliferation, thrombosis, remodeling or aneurysm formation. In contrast, VSMC apoptosis in atherosclerotic plaques of SM22alpha-hDTR Apoe-/- mice induced marked thinning of fibrous cap, loss of collagen and matrix, accumulation of cell debris and intense intimal inflammation. We conclude that VSMC apoptosis is 'silent' in normal arteries, which have a large capacity to withstand cell loss. In contrast, VSMC apoptosis alone is sufficient to induce features of plaque vulnerability in atherosclerosis. SM22alpha-hDTR Apoe-/- mice may represent an important new model to test agents proposed to stabilize atherosclerotic plaques.

A New Conjugation Method Used for the Development of an Immunoassay for the Detection of Amanitin, a Deadly Mushroom Toxin.

PubMed

Bever, Candace S; Barnych, Bogdan; Hnasko, Robert; Cheng, Luisa W; Stanker, Larry H

2018-06-28

One of the deadliest mushrooms is the death cap mushroom, Amanita phalloides . The most toxic constituent is α-amanitin, a bicyclic octapeptide, which damages the liver and kidneys. To develop a new tool for detecting this toxin, polyclonal antibodies were generated and characterized. Both α- and β-amanitin were coupled to carrier proteins through four different linking chemistries, one of which has never before been described. These conjugates were evaluated for their effectiveness in generating antibodies specific for the free toxin, as well as their utility in formatting heterogeneous assays with high sensitivity. Ultimately, these efforts yielded a newly described conjugation procedure utilizing periodate oxidation followed by reductive amination that successfully resulted in generating sensitive immunoassays (limit of detection (LOD), ~1.0 µg/L). The assays were characterized for their selectivity and were found to equally detect α-, β-, and γ-amanitin, and not cross-react with other toxins tested. Toxin detection in mushrooms was possible using a simple sample preparation method. This enzyme-linked immunosorbent assay (ELISA) is a simple and fast test, and readily detects amatoxins extracted from A. phalloides .

Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin.

PubMed

Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P N; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino; Ferlenghi, Ilaria; Bagnoli, Fabio

2016-06-01

Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. Copyright © 2016 Fiaschi et al.

Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin

PubMed Central

Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P. N.; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino

2016-01-01

Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. PMID:27030589

Static response of deformable microchannels

NASA Astrophysics Data System (ADS)

Christov, Ivan C.; Sidhore, Tanmay C.

2017-11-01

Microfluidic channels manufactured from PDMS are a key component of lab-on-a-chip devices. Experimentally, rectangular microchannels are found to deform into a non-rectangular cross-section due to fluid-structure interactions. Deformation affects the flow profile, which results in a nonlinear relationship between the volumetric flow rate and the pressure drop. We develop a framework, within the lubrication approximation (l >> w >> h), to self-consistently derive flow rate-pressure drop relations. Emphasis is placed on handling different types of elastic response: from pure plate-bending, to half-space deformation, to membrane stretching. The ``simplest'' model (Stokes flow in a 3D rectangular channel capped with a linearly elastic Kirchhoff-Love plate) agrees well with recent experiments. We also simulate the static response of such microfluidic channels under laminar flow conditions using ANSYSWorkbench. Simulations are calibrated using experimental flow rate-pressure drop data from the literature. The simulations provide highly resolved deformation profiles, which are difficult to measure experimentally. By comparing simulations, experiments and our theoretical models, we show good agreement in many flow/deformation regimes, without any fitting parameters.

Next-generation biomedical implants using additive manufacturing of complex, cellular and functional mesh arrays.

PubMed

Murr, L E; Gaytan, S M; Medina, F; Lopez, H; Martinez, E; Machado, B I; Hernandez, D H; Martinez, L; Lopez, M I; Wicker, R B; Bracke, J

2010-04-28

In this paper, we examine prospects for the manufacture of patient-specific biomedical implants replacing hard tissues (bone), particularly knee and hip stems and large bone (femoral) intramedullary rods, using additive manufacturing (AM) by electron beam melting (EBM). Of particular interest is the fabrication of complex functional (biocompatible) mesh arrays. Mesh elements or unit cells can be divided into different regions in order to use different cell designs in different areas of the component to produce various or continually varying (functionally graded) mesh densities. Numerous design elements have been used to fabricate prototypes by AM using EBM of Ti-6Al-4V powders, where the densities have been compared with the elastic (Young) moduli determined by resonant frequency and damping analysis. Density optimization at the bone-implant interface can allow for bone ingrowth and cementless implant components. Computerized tomography (CT) scans of metal (aluminium alloy) foam have also allowed for the building of Ti-6Al-4V foams by embedding the digital-layered scans in computer-aided design or software models for EBM. Variations in mesh complexity and especially strut (or truss) dimensions alter the cooling and solidification rate, which alters the alpha-phase (hexagonal close-packed) microstructure by creating mixtures of alpha/alpha' (martensite) observed by optical and electron metallography. Microindentation hardness measurements are characteristic of these microstructures and microstructure mixtures (alpha/alpha') and sizes.

A Multi-Year Budget Generation Program for Use in Navy Recruiting: A Users’ Manual,

DTIC Science & Technology

1981-10-01

251,069 for FY79 Monthly Unemploy- ment rate Oct. 78 6.48% 5.56 4.90 4.01 4.45 5.54 Nov. 78 6.25 5.14 6.31 4.13 4.96 5.82 De . 78 6.06 5.28 5.42 4.50...attrition factors), ALPHA (the elasticities for recruiters and the two types of advertising for 3 months), B (the elasticities for the 8 de /mographics...I 121 1 01 io~a! M -P. I II uA *--a W Q4M~IN-a~f a.0 M *CIO I t I’’ .i A 4a .81 it W * D. or 00W4 ŕ .1 2 de Q. r. ry, fy~- 01;4 : 46A am! 1 44 Me 0

Effect of capping and particle size on Raman laser-induced degradation of {gamma}-Fe{sub 2}O{sub 3} nanoparticles

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

Varadwaj, K.S.K.; Panigrahi, M.K.; Ghose, J.

2004-11-01

Diol capped {gamma}-Fe{sub 2}O{sub 3} nanoparticles are prepared from ferric nitrate by refluxing in 1,4-butanediol (9.5nm) and 1,5-pentanediol (15nm) and uncapped particles are prepared by refluxing in 1,2-propanediol followed by sintering the alkoxide formed. X-ray diffraction (XRD) shows that all the samples have the spinel phase. Raman spectroscopy shows that the samples prepared in 1,4-butanediol and 1,5-pentanediol and 1,2-propanediol (sintered at 573 and 673K) are {gamma}-Fe{sub 2}O{sub 3} and the 773K-sintered sample is Fe{sub 3}O{sub 4}. Raman laser studies carried out at various laser powers show that all the samples undergo laser-induced degradation to {alpha}-Fe{sub 2}O{sub 3} at higher lasermore » power. The capped samples are however, found more stable to degradation than the uncapped samples. The stability of {gamma}-Fe{sub 2}O{sub 3} sample with large particle size (15.4nm) is more than the sample with small particle size (10.2nm). Fe{sub 3}O{sub 4} having a particle size of 48nm is however less stable than the smaller {gamma}-Fe{sub 2}O{sub 3} nanoparticles.« less

Phase field models for heterogeneous nucleation: Application to inoculation in alpha-solidifying Ti-Al-B alloys

NASA Astrophysics Data System (ADS)

Apel, M.; Eiken, J.; Hecht, U.

2014-02-01

This paper aims at briefly reviewing phase field models applied to the simulation of heterogeneous nucleation and subsequent growth, with special emphasis on grain refinement by inoculation. The spherical cap and free growth model (e.g. A.L. Greer, et al., Acta Mater. 48, 2823 (2000)) has proven its applicability for different metallic systems, e.g. Al or Mg based alloys, by computing the grain refinement effect achieved by inoculation of the melt with inert seeding particles. However, recent experiments with peritectic Ti-Al-B alloys revealed that the grain refinement by TiB2 is less effective than predicted by the model. Phase field simulations can be applied to validate the approximations of the spherical cap and free growth model, e.g. by computing explicitly the latent heat release associated with different nucleation and growth scenarios. Here, simulation results for point-shaped nucleation, as well as for partially and completely wetted plate-like seed particles will be discussed with respect to recalescence and impact on grain refinement. It will be shown that particularly for large seeding particles (up to 30 μm), the free growth morphology clearly deviates from the assumed spherical cap and the initial growth - until the free growth barrier is reached - significantly contributes to the latent heat release and determines the recalescence temperature.

Cholinergic anti-inflammatory pathway in the non-obese diabetic mouse model.

PubMed

Koopman, F A; Vosters, J L; Roescher, N; Broekstra, N; Tak, P P; Vervoordeldonk, M J

2015-10-01

Activation of the cholinergic anti-inflammatory pathway (CAP) has been shown to reduce inflammation in animal models, while abrogation of the pathway increases inflammation. We investigated whether modulation of CAP influences inflammation in the non-obese diabetic (NOD) mouse model for Sjögren's syndrome and type 1 diabetes. The alpha-7 nicotinic acetylcholine receptor (α7nAChR) was stimulated with AR-R17779 or nicotine in NOD mice. In a second study, unilateral cervical vagotomy was performed. α7nAChR expression, focus scores, and salivary flow were evaluated in salivary glands (SG) and insulitis score in the pancreas. Cytokines were measured in serum and SG. α7nAChR was expressed on myoepithelial cells in SG. Monocyte chemotactic protein-1 levels were reduced in SG after AR-R17779 treatment and tumor necrosis factor production was increased in the SG of the vagotomy group compared to controls. Focus score and salivary flow were unaffected. NOD mice developed diabetes more rapidly after vagotomy, but at completion of the study there were no statistically significant differences in number of mice that developed diabetes or in insulitis scores. Intervention of the CAP in NOD mice leads to minimal changes in inflammatory cytokines, but did not affect overall inflammation and function of SG or development of diabetes. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Small Crack Growth and Its Influence in Near Alpha-Titanium Alloys

DTIC Science & Technology

1989-06-01

geometries via finite element and boundary-collocation analysis 8 , 9 . Elastic plastic fracture mechanics ( EPFM ) 1 0 , 1 1 and local crack tip field...correlation was found between experimental and predicted data, general application of the model is not possible as both 0 and rp are sensitive to changes in...cracks at low AK the load reduction schemes should be altered to remove the residual deformations, perhaps via machining or the application of large

Ballistocardiogram Artifact Removal with a Reference Layer and Standard EEG Cap

PubMed Central

Luo, Qingfei; Huang, Xiaoshan; Glover, Gary H.

2014-01-01

Background In simultaneous EEG-fMRI, the EEG recordings are severely contaminated by ballistocardiogram (BCG) artifacts, which are caused by cardiac pulsations. To reconstruct and remove the BCG artifacts, one promising method is to measure the artifacts in the absence of EEG signal by placing a group of electrodes (BCG electrodes) on a conductive layer (reference layer) insulated from the scalp. However, current BCG reference layer (BRL) methods either use a customized EEG cap composed of electrode pairs, or need to construct the custom reference layer through additional model-building experiments for each EEG-fMRI experiment. These requirements have limited the versatility and efficiency of BRL. The aim of this study is to propose a more practical and efficient BRL method and compare its performance with the most popular BCG removal method, the optimal basis sets (OBS) algorithm. New Method By designing the reference layer as a permanent and reusable cap, the new BRL method is able to be used with a standard EEG cap, and no extra experiments and preparations are needed to use the BRL in an EEG-fMRI experiment. Results The BRL method effectively removed the BCG artifacts from both oscillatory and evoked potential scalp recordings and recovered the EEG signal. Comparison with Existing Method Compared to the OBS, this new BRL method improved the contrast-to-noise ratios of the alpha-wave, visual, and auditory evoked potential signals by 101%, 76%, and 75% respectively, employing 160 BCG electrodes. Using only 20 BCG electrodes, the BRL improved the EEG signal by 74%/26%/41% respectively. Conclusion The proposed method can substantially improve the EEG signal quality compared with traditional methods. PMID:24960423

Exposure to concentrated ambient PM2.5 alters the composition of gut microbiota in a murine model.

PubMed

Wang, Wanjun; Zhou, Ji; Chen, Minjie; Huang, Xingke; Xie, Xiaoyun; Li, Weihua; Cao, Qi; Kan, Haidong; Xu, Yanyi; Ying, Zhekang

2018-04-17

Exposure to ambient fine particulate matter (PM 2.5 ) correlates with abnormal glucose homeostasis, but the underlying biological mechanism has not been fully understood. The gut microbiota is an emerging crucial player in the homeostatic regulation of glucose metabolism. Few studies have investigated its role in the PM 2.5 exposure-induced abnormalities in glucose homeostasis. C57Bl/6J mice were exposed to filtered air (FA) or concentrated ambient PM 2.5 (CAP) for 12 months using a versatile aerosol concentration enrichment system (VACES) that was modified for long-term whole-body exposures. Their glucose homeostasis and gut microbiota were examined and analysed by correlation and mediation analysis. Intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) showed that CAP exposure markedly impaired their glucose and insulin tolerance. Faecal microbiota analysis demonstrated that the impairment in glucose homeostasis was coincided with decreased faecal bacterial ACE and Chao-1 estimators (the indexes of community richness), while there was no significant change in all faecal fungal alpha diversity estimators. The Pearson's correlation analyses showed that the bacterial richness estimators were correlated with glucose and insulin tolerance, and the mediation analyses displayed a significant mediation of CAP exposure-induced glucose intolerance by the alteration in the bacterial Chao-1 estimator. LEfSe analyses revealed 24 bacterial and 21 fungal taxa differential between CAP- and FA-exposed animals. Of these, 14 and 20 bacterial taxa were correlated with IPGTT AUC and ITT AUC, respectively, and 5 fungal taxa were correlated with abnormalities in glucose metabolism. Chronic exposure to PM 2.5 causes gut dysbiosis and may subsequently contribute to the development of abnormalities in glucose metabolism.

Geophysical assessments of renewable gas energy compressed in geologic pore storage reservoirs.

PubMed

Al Hagrey, Said Attia; Köhn, Daniel; Rabbel, Wolfgang

2014-01-01

Renewable energy resources can indisputably minimize the threat of global warming and climate change. However, they are intermittent and need buffer storage to bridge the time-gap between production (off peak) and demand peaks. Based on geologic and geochemical reasons, the North German Basin has a very large capacity for compressed air/gas energy storage CAES in porous saltwater aquifers and salt cavities. Replacing pore reservoir brine with CAES causes changes in physical properties (elastic moduli, density and electrical properties) and justify applications of integrative geophysical methods for monitoring this energy storage. Here we apply techniques of the elastic full waveform inversion FWI, electric resistivity tomography ERT and gravity to map and quantify a gradually saturated gas plume injected in a thin deep saline aquifer within the North German Basin. For this subsurface model scenario we generated different synthetic data sets without and with adding random noise in order to robust the applied techniques for the real field applications. Datasets are inverted by posing different constraints on the initial model. Results reveal principally the capability of the applied integrative geophysical approach to resolve the CAES targets (plume, host reservoir, and cap rock). Constrained inversion models of elastic FWI and ERT are even able to recover well the gradual gas desaturation with depth. The spatial parameters accurately recovered from each technique are applied in the adequate petrophysical equations to yield precise quantifications of gas saturations. Resulting models of gas saturations independently determined from elastic FWI and ERT techniques are in accordance with each other and with the input (true) saturation model. Moreover, the gravity technique show high sensitivity to the mass deficit resulting from the gas storage and can resolve saturations and temporal saturation changes down to ±3% after reducing any shallow fluctuation such as that of groundwater table.

Cleavage of the actin-capping protein alpha -adducin at Asp-Asp-Ser-Asp633-Ala by caspase-3 is preceded by its phosphorylation on serine 726 in cisplatin-induced apoptosis of renal epithelial cells.

PubMed

van de Water, B; Tijdens, I B; Verbrugge, A; Huigsloot, M; Dihal, A A; Stevens, J L; Jaken, S; Mulder, G J

2000-08-18

Decreased phosphorylation of focal adhesion kinase and paxillin is associated with loss of focal adhesions and stress fibers and precedes the onset of apoptosis (van de Water, B., Nagelkerke, J. F., and Stevens, J. L. (1999) J. Biol. Chem. 274, 13328-13337). The cortical actin cytoskeletal network is also lost during apoptosis, yet little is known about the temporal relationship between altered phosphorylation of proteins that are critical in the regulation of this network and their potential cleavage by caspases during apoptosis. Adducins are central in the cortical actin network organization. Cisplatin caused apoptosis of renal proximal tubular epithelial cells, which was associated with the cleavage of alpha-adducin into a 74-kDa fragment; this was blocked by a general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk). Hemagglutinin-tagged human alpha-adducin was cleaved into a similar 74-kDa fragment by caspase-3 in vitro but not by caspase-6 or -7. Asp-Arg-Val-Asp(29)-Glu, Asp-Ile-Val-Asp(208)-Arg, and Asp-Asp-Ser-Asp(633)-Ala were identified as the principal caspase-3 cleavage sites; Asp-Asp-Ser-Asp(633)-Ala was key in the formation of the 74-kDa fragment. Cisplatin also caused an increased phosphorylation of alpha-adducin and gamma-adducin in the MARCKS domain that preceded alpha-adducin cleavage and was associated with loss of adducins from adherens junctions; this was not affected by z-VAD-fmk. In conclusion, the data support a model in which increased phosphorylation of alpha-adducin due to cisplatin leads to dissociation from the cytoskeleton, a situation rendered irreversible by caspase-3-mediated cleavage of alpha-adducin at Asp-Asp-Ser-Asp(633)-Ala.

Function of the two Xenopus smad4s in early frog development.

PubMed

Chang, Chenbei; Brivanlou, Ali H; Harland, Richard M

2006-10-13

Signals from the transforming growth factor beta family members are transmitted in the cell through specific receptor-activated Smads and a common partner Smad4. Two Smad4 genes (alpha and beta/10, or smad4 and smad4.2) have been isolated from Xenopus, and conflicting data are reported for Smad4beta/10 actions in mesodermal and neural induction. To further understand the functions of the Smad4s in early frog development, we analyzed their activities in detail. We report that Smad10 is a mutant form of Smad4beta that harbors a missense mutation of a conserved arginine to histidine in the MH1 domain. The mutation results in enhanced association of Smad10 with the nuclear transcription corepressor Ski and leads to its neural inducing activity through inhibition of bone morphogenetic protein (BMP) signaling. In contrast to Smad10, both Smad4alpha and Smad4beta enhanced BMP signals in ectodermal explants. Using antisense morpholino oligonucleotides (MOs) to knockdown endogenous Smad4 protein levels, we discovered that Smad4beta was required for both activin- and BMP-mediated mesodermal induction in animal caps, whereas Smad4alpha affected only the BMP signals. Neither Smad4 was involved directly in neural induction. Expression of Smad4beta-MO in early frog embryos resulted in reduction of mesodermal markers and defects in axial structures, which were rescued by either Smad4alpha or Smad4beta. Smad4alpha-MO induced only minor deficiency at late stages. As Smad4beta, but not Smad4alpha, is expressed at high levels maternally and during early gastrulation, our data suggest that although Smad4alpha and Smad4beta may have similar activities, they are differentially utilized during frog embryogenesis, with only Smad4beta being essential for mesoderm induction.

In situ strain profiling of elastoplastic bending in Ti-6Al-4V alloy by synchrotron energy dispersive x-ray diffraction

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

Croft, M.; National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973; Shukla, V.

Elastic and plastic strain evolution under four-point bending has been studied by synchrotron energy dispersive x-ray diffraction. Measured strain profiles across the specimen thickness showed an increasing linear elastic strain gradient under increasing four-point bending load up to approx2 kN. The bulk elastic modulus of Ti-6Al-4V was determined as 118 GPa. The onset of plastic deformation was found to set in at a total in-plane strain of approx0.008, both under tension and compression. Plastic deformation under bending is initiated in the vicinity of the surface and at a stress of 1100 MPa, and propagates inward, while a finite core regionmore » remains elastically deformed up to 3.67 kN loading. The onset of the plastic regime and the plastic regime itself has been verified by monitoring the line broadening of the (100) peak of alpha-Ti. The effective compression/tension stress-strain curve has been obtained from the scaling collapse of strain profile data taken at seven external load levels. A similar multiple load scaling collapse of the plastic strain variation has also been obtained. The level of precision in strain measurement reported herein was evaluated and found to be 1.5x10{sup -5} or better.« less

[Changes of interlukin-1beta and tumor necrosis factor-alpha levels in gingival crevicular fluid during orthodontic tooth movement].

PubMed

Tian, Yu-Lou; Xie, Jiang-Chun; Zhao, Zhen-Jin; Zhang, Yang

2006-06-01

To investigate the dynamic changes of interlukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in gingival crevicular fluid (GCF) during orthodontic tooth movement, and to discuss the biological significance. Fifteen patients were chosen as subjects. For each patient, upper and lower canines at one side having one treatment for distal movement by elastic chain served as the experimental teeth, whereas the contralateral ones were used as controls. The GCF were taken before activation and at 1, 24, 48, 72, 168 hours respectively after initiation of the experiment. The levels of IL-1beta and TNF-alpha in GCF were determined by radioimmunoassay. The levels of IL-1beta and TNF-alpha in experimental group began to increase at 24 hours and reached to its peak value at 72 hours after initiation of the experiment, but their levels returned to baseline at 168 hours. Both of them, however, remained at the baseline level in control group. The changes of the two cytokines level were found statistically significant at 48 and 72 hours (P<0.05) between experimental and control group. No statistically significant were observed before activation and at 1, 168 hours after application of orthodontic forces (P>0.05) between experimental and control group. The levels of IL-1beta and TNF-alpha in gingival crevicular fluid experience dynamic changes during the early phase of orthodontic treatment, indicate that they might play an important role in the process of alveolar regeneration and tooth movement.

Mechanics model for actin-based motility

NASA Astrophysics Data System (ADS)

Lin, Yuan

2009-02-01

We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

Propeller modelling effects on interior noise in cylindrical cavities with application to active control

NASA Technical Reports Server (NTRS)

Silcox, R. J.; Lester, H. C.

1989-01-01

The coupling of a vibrating finite elastic cylinder and its interior cavity, closed with rigid end caps, is examined. Results are presented for several types of excitation including a point force, a single external acoustic monopole, and an array of external monopoles. Modal spectra are examined for a frequency range typical of the harmonic noise produced by advanced turbo-props. The effect of frequency and source distribution on modal content is presented. Significant interface modal filtering, which would have a beneficial impact on an active system for reducing interior noise, was found to occur for all cases. Some preliminary experimental data for a stiffened, composite cylinder are presented and discussed.

Mechanics model for actin-based motility.

PubMed

Lin, Yuan

2009-02-01

We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

Fabrication and properties of multilayer structures

NASA Astrophysics Data System (ADS)

Tiller, W. A.

1983-09-01

The synthesis of SiC films and Pd2Si films via single source and dual source sputtering, respectively, has been experimentally investigated while the reactive sputter deposition of SiO sub x films has been theoretically analyzed. The SiO sub x film data requires a mobile precursor adsorption process to be operative for the oxygen and an oxygen sticking coefficient of between 1.56 x 10 to the minus 3rd power and 4.17 x 10 to the minus 3rd power. An analysis of in-situ electrical diagnostics of the films via a non-contact technique shows the method to be of marginal accuracy for the example selected. An important new formulation of the stress and elastic constant tensors in the vicinity of interfaces has been developed and applied to the simple example of adsorbed layer/substrate interactions via a parametric analysis. Atomic modeling of the SiO system yields peroxide bond formation for oxygen-rich (100) alpha-cristobalite surfaces. Radial distribution function and angular distribution function data have been calculated for bulk alpha-quartz and bulk alpha-cristobalite in good agreement with experiment.

Dehydrogenation of aromatic molecules under a scanning tunneling microscope: pathways and inelastic spectroscopy simulations.

PubMed

Lesnard, Hervé; Bocquet, Marie-Laure; Lorente, Nicolas

2007-04-11

We have performed a theoretical study on the dehydrogenation of benzene and pyridine molecules on Cu(100) induced by a scanning tunneling microscope (STM). Density functional theory calculations have been used to characterize benzene, pyridine, and different dehydrogenation products. The adiabatic pathways for single and double dehydrogenation have been evaluated with the nudge elastic band method. After identification of the transition states, the analysis of the electronic structure along the reaction pathway yields interesting information on the electronic process that leads to H-scission. The adiabatic barriers show that the formation of double dehydrogenated fragments is difficult and probably beyond reach under the actual experimental conditions. However, nonadiabatic processes cannot be ruled out. Hence, in order to identify the final dehydrogenation products, the inelastic spectra are simulated and compared with the experimental ones. We can then assign phenyl (C6H5) and alpha-pyridil (alpha-C5H4N) as the STM-induced dehydrogenation products of benzene and pyridine, respectively. Our simulations permit us to understand why phenyl, pyridine, and alpha-pyridil present tunneling-active C-H stretch modes in opposition to benzene.

Investigations of the structure and electromagnetic interactions of few body systems

NASA Astrophysics Data System (ADS)

Harper, E. P.; Lehman, D. R.; Prats, F.

The structure and electromagnetic interactions of few-body systems were investigated. The structural properties of the very light nuclei are examined by developing theoretical models that begin from the basic interactions between the constituents and that are solved exactly (numerically), i.e., full three- or four-body dynamics. Such models are then used in an attempt to understand the details of the strong and electromagnetic interactions of the few-nucleon nuclei after the basic underlying reaction mechanisms are understood with simpler models. Topics included: (1) set up the equations for the low-energy photodisintegration of (3)He and (3)H including final-state interactions and the E1 plus E2 operators; (2) develop a unified picture of the p + d (YIELDS) (3)He + (GAMMA), p + d (YIELDS) (3)He + (PI) (0), p + d (YIELDS) (3)H + (PI) (+) reactions at intermediate energies; (3) calculate the elastic and inelastic (1(+) (YIELDS) 0 (+)) form factors for (6)Li with three-body ((ALPHA)NN) wave functions; (4) calculate static properties (RMS radius, magnetic moment, and quadrupole moment) of (6)Li with three-body wave functions; and (5) develop the theory for the coincidence reactions (6)Li(p,2p)n(ALPHA), (6)Li(e,e'p)n(ALPHA), and (6)Li(e,e'd)(ALPHA).

On determining dead layer and detector thicknesses for a position-sensitive silicon detector

NASA Astrophysics Data System (ADS)

Manfredi, J.; Lee, Jenny; Lynch, W. G.; Niu, C. Y.; Tsang, M. B.; Anderson, C.; Barney, J.; Brown, K. W.; Chajecki, Z.; Chan, K. P.; Chen, G.; Estee, J.; Li, Z.; Pruitt, C.; Rogers, A. M.; Sanetullaev, A.; Setiawan, H.; Showalter, R.; Tsang, C. Y.; Winkelbauer, J. R.; Xiao, Z.; Xu, Z.

2018-04-01

In this work, two particular properties of the position-sensitive, thick silicon detectors (known as the "E" detectors) in the High Resolution Array (HiRA) are investigated: the thickness of the dead layer on the front of the detector, and the overall thickness of the detector itself. The dead layer thickness for each E detector in HiRA is extracted using a measurement of alpha particles emitted from a 212Pb pin source placed close to the detector surface. This procedure also allows for energy calibrations of the E detectors, which are otherwise inaccessible for alpha source calibration as each one is sandwiched between two other detectors. The E detector thickness is obtained from a combination of elastically scattered protons and an energy-loss calculation method. Results from these analyses agree with values provided by the manufacturer.

Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector.

PubMed

Pöllänen, R; Siiskonen, T

2014-08-01

The response of a semiconductor alpha detector to fast (>1 MeV) neutrons was investigated by using measurements and simulations. A polyethylene converter was placed in front of the detector to register recoil protons generated by elastic collisions between neutrons and hydrogen nuclei of the converter. The developed prototype equipment was tested with shielded radiation sources. The low background of the detector and insensitivity to high-energy gamma rays above 1 MeV are advantages when the detection of neutron-emitting nuclear materials is of importance. In the case of a (252)Cf neutron spectrum, the intrinsic efficiency of fast neutron detection was determined to be 2.5×10(-4), whereas three-fold greater efficiency was obtained for a (241)AmBe neutron spectrum. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Physical therapy intervention during hospitalization in patients with acute exacerbation of chronic obstructive pulmonary disease and pneumonia: A randomized clinical trial].

PubMed

Martín-Salvador, Adelina; Colodro-Amores, Gloria; Torres-Sánchez, Irene; Moreno-Ramírez, M Paz; Cabrera-Martos, Irene; Valenza, Marie Carmen

2016-04-01

Respiratory infections involve not only hospitalization due to pneumonia, but also acute exacerbations of COPD (AECOPD). The objective of the present study was to evaluate the effectiveness of a physical therapy intervention during hospitalization in patients admitted due to community-acquired pneumonia (CAP) and AECOPD. Randomized clinical trial, 44 patients were randomized into 2 groups: a control group which received standard medical therapy (oxygen therapy and pharmacotherapy) and an experimental group that received standard treatment and a physical therapy intervention (breathing exercises, electrostimulation, exercises with elastic bands and relaxation). Between-groups analysis showed that after the intervention (experimental vs. control) significant differences were found in perceived dyspnoea (P=.041), and right and left quadriceps muscle strength (P=.008 and P=.010, respectively). In addition, the subscale of "domestic activities" of the functional ability related to respiratory symptoms questionnaire showed significant differences (P=.036). A physical therapy intervention during hospitalization in patients with AECOPD and CAP can generate skeletal muscle level gains that exceed the deterioration caused by immobilization during hospitalization. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Evidence of a slight nuclear transparency in the alpha-nucleus systems

DOE PAGES

Chamon, L. C.; Gasques, L. R.; Nobre, G. P. A.; ...

2015-02-19

In earlier works, we proposed a model for the nuclear potential of the α + α and α + ¹²C systems. In addition, this theoretical model successfully described data related to the elastic and inelastic scattering processes as well as resonances that correspond to the capture reaction channel. In the present work, we extend the same model to obtain bare nuclear potentials for several α-nucleus systems. We adopt this parameter-free interaction to analyze fusion, elastic, and inelastic scattering data within the context of the coupled-channel formalism. Our results indicate that, for these systems, the absorption of flux of the elasticmore » channel at internal distances of interaction is not complete. In addition, we present new experimental angular distributions for the 2⁺ inelastic target excitation of α on ¹²⁰ ,¹³⁰Te.« less

The Effect of a Helix-Coil Transition on the Extension Elasticity

NASA Astrophysics Data System (ADS)

Buhot, Arnaud; Halperin, Avi

2000-03-01

The secondary structure of a polymer affects its deformation behavior in accordance with the Le Chatelier principle. An important example of such secondary structure is the alpha helix encountered in polypeptides. Similar structure was recently proposed for PEO in aqueous media. Our discussion concerns the coupling of the cooperative helix-coil transition and the extension elasticity. In particular, we analyze the extension of a long single chain by use of optical tweezers or AFM. We consider chains that exist in the coil-state when unperturbed. The transition nevertheless occurs because the extension favors the low entropy helical state. As a result, the corresponding force law exhibits a plateau. The analysis of this situation involves two ingredients: (I) the stretching free energy penalty for a rod-coil mutiblock copolymer (II) the entropy associated with the possible placements of the rod and coil blocks.

Study of the mechanical behavior of the hydride blister/rim structure in Zircaloy-4 using in-situ synchrotron X-ray diffraction

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

Lin, Jun-li; Han, Xiaochun; Heuser, Brent J.

2016-04-01

High-energy synchrotron X-ray diffraction was utilized to study the mechanical response of the f.c.c delta hydride phase, the intermetallic precipitation with hexagonal C14 lave phase and the alpha-Zr phase in the Zircaloy-4 materials with a hydride rim/blister structure near one surface of the material during in-situ uniaxial tension experiment at 200 degrees C. The f.c.c delta was the only hydride phase observed in the rim/blister structure. The conventional Rietveld refinement was applied to measure the macro-strain equivalent response of the three phases. Two regions were delineated in the applied load versus lattice strain measurement: a linear elastic strain region andmore » region that exhibited load partitioning. Load partitioning was quantified by von Mises analysis. The three phases were observed to have similar elastic modulus at 200 degrees C.« less

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

Sanchez, G.P.

The interactions of a CH = CH target with a 29-Mev He/sup 3/ particles beam were analyzed. The results for elastic and inelastic processes C/sup 12/(He/ sup 3/, He/sup 3/)C/sup 12/ C/sup 12/(He/sup 3/ He/sup 3/)C/sup -12/ C/sup 12/(He/ sup 3/, alpha )C/sup 11/, C/sup 12/(He/sup 3/, d)N/sup 13/, and H/sup 1/(He/sup 3/, He/sup 3/)H/sup 1/ are presented. For the interaction radius, a value of 5.35 plus or minus 0.24 fermis was obtained by the black disk formula. The observed angular distributions were compared, when possible, with the predictions of Blair and A.B.M. direct interaction theories. The angular distributions formore » the elastic scattering of He/sup 3/ by H/sup 1/ was checked with theoretical predictions based on the resonating group theory. (auth)« less

Free Body Dynamics of a Spinning Cylinder With Planar Restraint (a.k.a. Barrel of Fun)

NASA Technical Reports Server (NTRS)

Moraru, Laurentiu; Dimofte, Florin; Hendricks, Robert C.

2006-01-01

The dynamic motion of a cylinder on a floor or hard surface is both entertaining and instructive. With maintenance torques, motion can be sustained and controlled as illustrated in a video clip that can be viewed in the PDF file of this document. The analysis of such a cylinder with and without end caps is burned on rotation about its center of mass and restrained by a plane normal to the axis passing through its center of mass at an angle alpha. For small values of alpha, the governing equations are simplified, and for symmetric bodies, stability requires rotation greater than [2 square root of(JWL*)]/J(sub X), where J is the transverse mass moment of inertia, W is the weight of the cylinder, L* is the cylinder length from the base to the center of mass, and JX is the mass moment of inertia about the longitudinal axis OX of the barrel. Comparisons to data are made and some applications are discussed.

Identification of high-mannose and multiantennary complex-type N-linked glycans containing alpha-galactose epitopes from Nurse shark IgM heavy chain.

PubMed

Harvey, David J; Crispin, Max; Moffatt, Beryl E; Smith, Sylvia L; Sim, Robert B; Rudd, Pauline M; Dwek, Raymond A

2009-11-01

MALDI-TOF mass spectrometry, negative ion nano-electrospray MS/MS and exoglycosidase digestion were used to identify 36 N-linked glycans from 19S IgM heavy chain derived from the nurse shark (Ginglymostoma cirratum). The major glycan was the high-mannose compound, Man(6)GlcNAc(2) accompanied by small amounts of Man(5)GlcNAc(2), Man(7)GlcNAc(2) and Man(8)GlcNAc(2). Bi- and tri-antennary (isomer with a branched 3-antenna) complex-type glycans were also abundant, most contained a bisecting GlcNAc residue (beta1-->4-linked to the central mannose) and with varying numbers of alpha-galactose residues capping the antennae. Small amounts of monosialylated glycans were also found. This appears to be the first comprehensive study of glycosylation in this species of animal. The glycosylation pattern has implications for the mechanism of activation of the complement system by nurse shark IgM.

The ionosphere of Uranus - A myriad of possibilities

NASA Astrophysics Data System (ADS)

Chandler, M. O.; Waite, J. H.

1986-01-01

A one-dimensional model has been used to study the effects of exospheric temperature, methane and water influx, ionospheric outflow, and electron precipitation on the composition and structure of the ionosphere of Uranus. Peak ion concentrations range from 1000 to 1 million per cu cm with a wide variation in peak altitude, which depends strongly on the exospheric temperature. In all the cases considered, H(+) is the major ion in the topside ionosphere. At altitudes near or below the peak, H3(+) and CH5(+) can dominate, depending on the magnitude of CH4 and H2O influx. Atomic hydrogen column depths above the methane absorbing layer exceed 10 to the 17th per sq cm and can produce large (400 R) emissions of resonantly scattered Lyman-alpha. In the sunlit polar cap, electron precipitation with energy fluxes of 0.6 to 1.0 erg/sq cm s results in direct production of Lyman-alpha emissions that exceed 1 kR.

Enzymatic transformation of nonfood biomass to starch

PubMed Central

You, Chun; Chen, Hongge; Myung, Suwan; Sathitsuksanoh, Noppadon; Ma, Hui; Zhang, Xiao-Zhou; Li, Jianyong; Zhang, Y.-H. Percival

2013-01-01

The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world’s future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture’s environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma. PMID:23589840

Formation and self-organization kinetics of alpha-CD/PEO-based pseudo-polyrotaxanes in water. A specific behavior at 30 degrees C.

PubMed

Travelet, Christophe; Schlatter, Guy; Hébraud, Pascal; Brochon, Cyril; Lapp, Alain; Hadziioannou, Georges

2009-08-04

alpha-Cyclodextrins (alpha-CDs) have the ability to form inclusion complexes with poly(ethylene oxide) (PEO) polymer chains. These pseudo-polyrotaxanes (PPRs) can be obtained by quenching an alpha-CD/PEO mixture in water from 70 degrees C down to a lower temperature (typically in the range from 5 to 30 degrees C) thanks to favorable interactions between alpha-CD cavities and PEO chains. Moreover, starting from a liquid alpha-CD/PEO mixture at a total mass fraction of 15% w/w at 70 degrees C, the formation of PPRs with time at a lower temperature induces a white physical gel with time, and phase separation is observed. We established that PPR molecules are exclusively found in the precipitated phase although unthreaded alpha-CD molecules and unthreaded PEO chains are in the liquid phase. At 30 degrees C, the physical gel formation is much slower than at 5 degrees C. At 30 degrees C, we established that, in a first step, alpha-CDs thread onto PEO chains, forming PPR molecules which are not in good solvent conditions in water. At a higher length scale, rapid aggregation of the PPR molecules occurs, and threaded alpha-CD-based nanocylinders form (cylinder length L = 5.7 nm and cylinder radius R = 4.7 nm). At a higher length scale, alpha-CD-based nanocylinders associate in a Gaussian way, engendering the formation of precipitated domains which are responsible for the high turbidity of the studied system. At the end of this first step (i.e., after 20 min), the system still remains liquid and the PPRs are totally formed. Then, in a second step (i.e., after 150 min), the system undergoes its reorganization characterized by a compacity increase of the precipitated domains and forms a physical gel. We found that PPRs are totally formed after 20 min at 30 degrees C and that the system stays in a nongel state up to 150 min. This opens new perspectives regarding the PPR chemical modification: between these two characteristic times, we can easily envisage an efficient chemical modification of the PPR molecules in water, as for instance an end-capping reaction leading to the synthesis of polyrotaxanes.

Detection of Rupture-Prone Atherosclerotic Plaques by Time-Resolved Laser Induced Fluorescence Spectroscopy

PubMed Central

Marcu, Laura; Jo, Javier A.; Fang, Qiyin; Papaioannou, Thanassis; Reil, Todd; Qiao, Jian-Hua; Baker, J. Dennis; Freischlag, Julie A.; Fishbein, Michael C.

2009-01-01

Objective Plaque with dense inflammatory cells, including macrophages, thin fibrous cap and superficial necrotic/lipid core is thought to be prone-to-rupture. We report a time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) technique for detection of such markers of plaque vulnerability in human plaques. Methods The autofluorescence of carotid plaques (65 endarterectomy patients) induced by a pulsed laser (337 nm, 0.7 ns) was measured from 831 distinct areas. The emission was resolved spectrally- (360–550 nm range) and temporally- (0.3 ns resolution) using a prototype fiber-optic TR-LIFS apparatus. Lesions were evaluated microscopically and quantified as to the % of different components (fibrous cap, necrotic core, inflammatory cells, foam cells, mature and degraded collagen, elastic fibers, calcification, and smooth muscle cell of the vessel wall). Results We determined that the spectral intensities and time-dependent parameters at discrete emission wavelengths 1) allow for discrimination (sensitivity >81%, specificity >94%) of various compositional and pathological features associated with plaque vulnerability including infiltration of macrophages into intima and necrotic/lipid core under a thin fibrous cap, and 2) show a linear correlation with plaque biochemical content: elastin (P<0.008), collagen (P<0.02), inflammatory cells (P<0.003), necrosis (P<0.004). Conclusion Our results demonstrate the feasibility of TR-LIFS as a method for the identification of markers of plaque vulnerability. Current findings enable future development of TR-LIFS based clinical devices for rapid investigation of atherosclerotic plaques and detection of those at high-risk. PMID:18926540

Mechanical properties and fractal analysis of the surface texture of sputtered hydroxyapatite coatings

NASA Astrophysics Data System (ADS)

Bramowicz, Miroslaw; Braic, Laurentiu; Azem, Funda Ak; Kulesza, Slawomir; Birlik, Isil; Vladescu, Alina

2016-08-01

This aim of this work is to establish a relationship between the surface morphology and mechanical properties of hydroxyapatite coatings prepared using RF magnetron sputtering at temperatures in the range from 400 to 800 °C. The topography of the samples was scanned using atomic force microscopy, and the obtained 3D maps were analyzed using fractal methods to derive the spatial characteristics of the surfaces. X-ray photoelectron spectroscopy revealed the strong influence of the deposition temperature on the Ca/P ratio in the growing films. The coatings deposited at 600-800 °C exhibited a Ca/P ratio between 1.63 and 1.69, close to the stoichiometric hydroxyapatite (Ca/P = 1.67), which is crucial for proper osseointegration. Fourier-transform infrared spectroscopy showed that the intensity of phosphate absorption bands increased with increasing substrate temperature. Each sample exhibited well defined and sharp hydroxyapatite band at 566 cm-1, although more pronounced for the coatings deposited above 500 °C. Both the hardness and elastic modulus of the coated samples decrease with increasing deposition temperature. The surface morphology strongly depends on the deposition temperature. The sample deposited at 400 °C exhibits circular cavities dug in an otherwise flat surface. At higher deposition temperatures, these cavities increase in size and start to overlap each other so that at 500 °C the surface is composed of closely packed peaks and ridges. At that point, the characteristics of the surface turns from the dominance of cavities to grains of similar size, and develops in a similar manner at higher temperatures.

PR65, the HEAT-repeat scaffold of phosphatase PP2A, is an elastic connector that links force and catalysis.

PubMed

Grinthal, Alison; Adamovic, Ivana; Weiner, Beth; Karplus, Martin; Kleckner, Nancy

2010-02-09

PR65 is the two-layered (alpha-alpha solenoid) HEAT-repeat (Huntingtin, elongation factor 3, a subunit of protein phosphatase 2A, PI3 kinase target of rapamycin 1) scaffold of protein phosphatase PP2A. Molecular dynamics simulations predict that, at forces expected in living systems, PR65 undergoes (visco-)elastic deformations in response to pulling/pushing on its ends. At lower forces, smooth global flexural and torsional changes occur via even redistribution of stress along the hydrophobic core of the molecule. At intermediate forces, helix-helix separation along one layer ("fracturing") leads to global relaxation plus loss of contact in the other layer to unstack the affected units. Fracture sites are determined by unusual sequences in contiguous interhelix turns. Normal mode analysis of the heterotrimeric PP2A enzyme reveals that its ambient conformational fluctuations are dominated by elastic deformations of PR65, which introduce a mechanical linkage between the separately bound regulatory and catalytic subunits. PR65-dominated fluctuations of PP2A have the effect of opening and closing the enzyme's substrate binding/catalysis interface, as well as altering the positions of certain catalytic residues. These results suggest that substrate binding/catalysis are sensitive to mechanical force. Force could be imposed from the outside (e.g., in PP2A's response to spindle tension) or arise spontaneously (e.g., in PP2A's interaction with unstructured proteins such as Tau, a microtubule-associated Alzheimer's-implicated protein). The presented example supports the view that conformation and function of protein complexes can be modulated by mechanical energy inputs, as well as by chemical energy inputs from ligand binding. Given that helical-repeat proteins are involved in many cellular processes, the findings also encourage the view that mechanical forces may be of widespread importance.

Measuring alcohol-related consequences and motives among students attending Historically Black Colleges and Universities.

PubMed

Messina, Bryan G; Tseng, Andy; Correia, Christopher J

2015-07-01

College student drinkers have the propensity to engage in heavy alcohol consumption. These consumption patterns can be problematic given the well-established relationship between heavy drinking and negative consequences of alcohol consumption. Though the research on college student drinking is abundant, much of the work conducted has been with Caucasian samples and less so with African American samples or at Historically Black Colleges and Universities (HBCUs). The current paper assessed the internal reliability and concurrent validity of two popular measures of alcohol related negative consequences (CAPS-r and YAACQ) and a measure of drinking motives (DMQ-R) within a HBCU sample. Total scores for the CAPS-r and YAACQ and all five subscales of the DMQ-R were internally reliable as determined by Cronbach's alpha. Correlations and regressions established concurrent validity for both measures of negative consequences as well as the subscales for the DMQ-R. Findings support the use of these measures in the assessment of negative consequences and motivations for alcohol consumption within a HBCU population. Copyright © 2015 Elsevier Ltd. All rights reserved.

Creep function of a single living cell.

PubMed

Desprat, Nicolas; Richert, Alain; Simeon, Jacqueline; Asnacios, Atef

2005-03-01

We used a novel uniaxial stretching rheometer to measure the creep function J(t) of an isolated living cell. We show, for the first time at the scale of the whole cell, that J(t) behaves as a power-law J(t) = At(alpha). For N = 43 mice myoblasts (C2-7), we find alpha = 0.24 +/- 0.01 and A = (2.4 +/- 0.3) 10(-3) Pa(-1) s(-alpha). Using Laplace Transforms, we compare A and alpha to the parameters G(0) and beta of the complex modulus G*(omega) = G(0)omega(beta) measured by other authors using magnetic twisting cytometry and atomic force microscopy. Excellent agreement between A and G(0) on the one hand, and between alpha and beta on the other hand, indicated that the power-law is an intrinsic feature of cell mechanics and not the signature of a particular technique. Moreover, the agreement between measurements at very different size scales, going from a few tens of nanometers to the scale of the whole cell, suggests that self-similarity could be a central feature of cell mechanical structure. Finally, we show that the power-law behavior could explain previous results first interpreted as instantaneous elasticity. Thus, we think that the living cell must definitely be thought of as a material with a large and continuous distribution of relaxation time constants which cannot be described by models with a finite number of springs and dash-pots.

How perfect can a gluon plasma be in perturbative QCD?

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

Chen, Jiunn-Wei; Deng Jian; Dong Hui

2011-02-01

The shear viscosity to entropy density ratio, {eta}/s, characterizes how perfect a fluid is. We calculate the leading order {eta}/s of a gluon plasma in perturbation using the kinetic theory. The leading order contribution only involves the elastic gg{r_reversible}gg (22) process and the inelastic gg{r_reversible}ggg (23) process. The hard-thermal-loop (HTL) treatment is used for the 22 matrix element, while the exact matrix element in vacuum is supplemented by the gluon Debye mass insertion for the 23 process. Also, the asymptotic mass is used for the external gluons in the kinetic theory. The errors from not implementing HTL and the Landau-Pomeranchuk-Migdalmore » effect in the 23 process, and from the uncalculated higher order corrections, are estimated. Our result smoothly connects the two different approximations used by Arnold, Moore, and Yaffe (AMY) and Xu and Greiner (XG). At small {alpha}{sub s} ({alpha}{sub s}<<1), our result is closer to AMY's collinear result while at larger {alpha}{sub s} the finite angle noncollinear configurations become more important and our result is closer to XG's soft bremsstrahlung result. In the region where perturbation is reliable ({alpha}{sub s} < or approx. 0.1), we find no indication that the proposed perfect fluid limit {eta}/s{approx_equal}1/(4{pi}) can be achieved by perturbative QCD alone. Whether this can be achieve for {alpha}{sub s} > or approx. 0.1 is still an open question.« less

Identification of a "glycine-loop"-like coiled structure in the 34 AA Pro,Gly,Met repeat domain of the biomineral-associated protein, PM27.

PubMed

Wustman, Brandon A; Santos, Rudolpho; Zhang, Bo; Evans, John Spencer

2002-12-05

Fracture resistance in biomineralized structures has been linked to the presence of proteins, some of which possess sequences that are associated with elastic behavior. One such protein superfamily, the Pro,Gly-rich sea urchin intracrystalline spicule matrix proteins, form protein-protein supramolecular assemblies that modify the microstructure and fracture-resistant properties of the calcium carbonate mineral phase within embryonic sea urchin spicules and adult sea urchin spines. In this report, we detail the identification of a repetitive keratin-like "glycine-loop"- or coil-like structure within the 34-AA (AA: amino acid) N-terminal domain, (PGMG)(8)PG, of the spicule matrix protein, PM27. The identification of this repetitive structural motif was accomplished using two capped model peptides: a 9-AA sequence, GPGMGPGMG, and a 34-AA peptide representing the entire motif. Using CD, NMR spectrometry, and molecular dynamics simulated annealing/minimization simulations, we have determined that the 9-AA model peptide adopts a loop-like structure at pH 7.4. The structure of the 34-AA polypeptide resembles a coil structure consisting of repeating loop motifs that do not exhibit long-range ordering. Given that loop structures have been associated with protein elastic behavior and protein motion, it is plausible that the 34-AA Pro,Gly,Met repeat sequence motif in PM27 represents a putative elastic or mobile domain. Copyright 2002 Wiley Periodicals, Inc.

Proecdysial changes in serum ecdysone titers, gastrolith formation, and limb regeneration following molt induction by limb autotomy and/or eyestalk removal in the land crab, Gecarcinus lateralis

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

McCarthy, J.F.; Skinner, D.M.

1977-01-01

The changes in serum ecdysone titers, gastrolith deposition, and limb regeneration were monitored at each stage of the molt cycle in the land crab, Gecarcinus lateralis. Animals were induced to molt by multiple-limb autotomy or eyestalk removal. The presence of ..cap alpha..-ecdysone and b-ecdysone (20-hydroxyecdysone) in the animals' serum was demonstrated chromatographically. ..beta..-ecdysone was the major circulating ecdysone, while ..cap alpha..-ecdysone was present only at very low concentrations. Four other components reacting with the ecdysone antiserum were separated chromatographically; one of these, a nonpolar compound, became a major component of the serum ecdysones at the time of maximum hormone titers.more » Ecdysone titers in the serum remained at the level characteristic of intermolt (approximately 10 ng/ml) during basal regeneration and rose linearly during the premolt period, reaching a maximum when regeneration of limbs had ceased and exoskeleton was deposited. Ecdysone decreased during stages D/sub 3/ and D/sub 4/, approaching intermolt levels at the time of ecdysis, where they remained through postmolt stages A and B. The patterns of premolt changes in ecdysone titers, gastroliths, and regeneration were very similar in ''normal'' animals (stimulated to molt by the loss of eight pereiopods) and in animals without eyestalks; however, in crabs without eyestalks, the changes were completed in about half the time as in crabs with eyestalks. Basal regeneration is associated with low ecdysone levels even in crabs without eyestalks. The normal sequence of proecdysial events is not initiated until the completion of basal regeneration. It is suggested that there exists a yet-unidentified mechanism outside the eyestalk capable of preventing increases in ecdysone titers while limbs engage in basal regeneration.« less

Interaction of tachykinins with their receptors studied with cyclic analogues of substance P and neurokinin B

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

Ploux, O.; Lavielle, S.; Chassaing, G.

1987-11-01

The activities of two groups of cyclic agonists of substance P (SP) have been studied. The disulfide bridge constraints have been designed on the basis of conformational studies on SP and physalaemin indicating an ..cap alpha..-helical structure for the core of these two tachykinins (group I) and a folding of the C-terminal carboxamide towards the side chains of the glutamines 5 and 6 (group II). Only peptides simulating the ..cap alpha..-helix present substantial potencies. (Cys/sup 3,6/)SP is as active as SP in inhibiting /sup 125/I-labeled Bolton and Hunter SP-specific binding on rat brain synaptosomes and on dog carotid bioassay, twomore » assays specific for the neurokinin 1 receptor. Moreover, (Cys/sup 3,6/)SP is a potent as neurokinin B in inhibiting /sup 125/I-labeled Bolton and Hunter eledoisin-specific binding on rat cortical synaptosomes as well as in stimulating rat portal vein, two tests specific for the neurokinin 3 receptor. Interestingly, in contrast to neurokinin B, (Cys/sup 3,6/)SP is a weak agonist of the neurokinin 2 receptor subtype, as evidenced by its binding potency in inhibiting /sup 3/H-labeled neurokinin A-specific binding on rat duodenum and in inducing the contractions of the rabbit pulmonary artery, a neurokinin 2-type bioassay. To increase the specificity of the cyclic analogue (Cys/sup 3,6/)SP positions 8 and 9 were modified. Collectively, these results suggest that the neurokinin 1 and neurokinin 3 tachykinin receptors may recognize a similar three-dimensional structure of the core of the tachykinins. Different orientations of the common C-terminal tripeptide may be related to the selectivity for the different receptor subtypes.« less

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

Inbar, S.; Linschitz, H.; Cohen, S.G.

Nanosecond flash photolysis, steady irradiation, and deuterium substitution studies have been carried out on solutions of benzophenone with added reductants. Quantum yields (phi/sub ketyl/) for reduction in benzene of benzophenone triplet to ketyl radical, based on phi = 2 for benzhydrol (I), were approx. 1 for cyclohexane (II), tert-butylamine (III), 2-aminobutane (IV), cyclohexylamine (V), di-n-propylamine (VI), and triethylamine (VII), approx. 0.7 for 1,4-diazabicyclo(2.2.2)octane (VIII), and approx. 0 for tert-butyl alcohol (IX). Thus, quenching, without radical formation by H abstraction from N and/or ..cap alpha..-C, does not occur with common aliphatic amines but does with Dabco (VIII). The latter quenching ismore » markedly increased by small additions of acetonitrile; the flash spectrum from this compound indicates formation of a triplet amine CT complex or radical ion pair. Triplet-reductant interaction rate constants, k/sur ir/, are high for the amines (approx. 10/sup 8/-10/sup 9/ M/sup -1/ s/sup -1/) but also show significant deuterium kinetic isotope effects: 1.9 with III-N-d/sub 2/; 1.4 with IV-N-d/sub 2/; 1.2-1.3 with IV-..cap alpha..-C-d. It is proposed that k/sub ir/ measures H atom abstraction, favored in the transition state by an initial charge-transfer interaction. Overall steady irradiation quantum yields of reduction by amines, phi/sub Red/, are much lower than phi/sub ketyl/. This is attributed to disproportionationreactions of ketyl and alkylaminyl radicals for primary and secondary amines, and, possibly, aminoalkyl radicals for tertiary amines. In the case of tert-butylamine, the rate constant for disproportionation is obtained from the decay kinetics of ketyl radical and leads to phi/sub Red/ in agreement with that directly measured.« less

The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar's Gamma-Ray Light Curves

NASA Technical Reports Server (NTRS)

Barnard, M.; Venter, C.; Harding, A. K.

2016-01-01

We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter epsilon), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to epsilon equals 0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle alpha equals 78 plus or minus 1 degree and observer angle zeta equals 69 plus 2 degrees or minus 1 degree. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of epsilon are favored for the offset-PC dipole field when assuming constant emissivity, and larger epsilon values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with alpha and zeta being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

Characterization of irradiated blends of alpha-tocopherol and UHMWPE.

PubMed

Oral, Ebru; Greenbaum, Evan S; Malhi, Arnaz S; Harris, William H; Muratoglu, Orhun K

2005-11-01

Adhesive/abrasive wear in ultra-high molecular weight polyethylene (UHMWPE) has been minimized by radiation cross-linking. Irradiation is followed by melting to eliminate residual free radicals and avoid long-term oxidative embrittlement. However, post-irradiation melting reduces the crystallinity of the polymer and hence its strength and fatigue resistance. We proposed an alternative to post-irradiation melting to be the incorporation of the antioxidant alpha-tocopherol into UHMWPE prior to consolidation. alpha-Tocopherol is known to react with oxygen and oxidized lipids, stabilizing them against further oxidative degradation reactions. We blended GUR 1050 UHMWPE resin powder with alpha-tocopherol at 0.1 and 0.3 wt% and consolidated these blends. Then we gamma-irradiated these blends to 100-kGy. We characterized the effect of alpha-tocopherol on the cross-linking efficiency, oxidative stability, wear behavior and mechanical properties of the blends. (I) The cross-link density of virgin, 0.1 and 0.3 wt% alpha-tocopherol blended, 100-kGy irradiated UHMWPEs were 175+/-19, 146+/-4 and 93+/-4 mol/m3, respectively. (II) Maximum oxidation indices for 100-kGy irradiated UHMWPE previously blended with 0, 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 3.32, 0.09, and 0.05, respectively. (III) The pin-on-disc wear rates of 100-kGy irradiated UHMWPE previously blended with 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 2.10+/-0.17 and 5.01+/-0.76 mg/million cycles, respectively. (IV) Both accelerated aged, alpha-tocopherol-blended 100-kGy irradiated UHMWPEs showed higher ultimate tensile strength, higher yield strength, and lower elastic modulus when compared to 100-kGy irradiated, virgin UHMWPE. These results showed that alpha-tocopherol-blended 100-kGy irradiated UHMWPEs were not cross-linked to the same extent as the 100-kGy irradiated, virgin UHMWPE.

Structural features of the exocellular polysaccharides of Mycobacterium tuberculosis.

PubMed Central

Lemassu, A; Daffé, M

1994-01-01

The cell envelope which surrounds pathogenic mycobacteria is postulated to be a defence barrier against phagocytic cells and its outermost constituents have a tendency to accumulate in the culture medium. The present work demonstrates that the exocellular material of Mycobacterium tuberculosis contains large amounts of polysaccharides with only traces, if any at all, of lipids. Three types of polysaccharides were purified by anion-exchange and gel-filtration chromatography; all were found to be neutral compounds devoid of acyl substituents. They consisted of D-glucan, D-arabino-D-mannan and D-mannan, which were eluted from gel-filtration columns in positions corresponding to molecular masses of 123, 13 and 4 kDa respectively. Their predominant structural features were determined by the characterization of the per-O-methyl derivatives of enzymic, acetolysis and Smith-degradation products and by 1H- and 13C-n.m.r. spectroscopy of the purified polysaccharides, using mono- and two-dimensional homonuclear chemical-shift correlated spectroscopy and two-dimensional heteronuclear (1H/13C) spectroscopy. The glucan which represented up to 90% of the polysaccharides was composed of repeating units of five or six-->4-alpha-D-Glcp-1--> residues and a -->4-alpha-D-Glcp substituted at position 6 with an alpha-D-Glcp, indicating a glycogen-like highly branched structure not related to the so-called polysaccharide-II previously identified in tuberculin. The arabinomannan consisted of a mannan segment composed of a -->6-alpha-D-Man-1--> core substituted at some positions 2 with an alpha-D-Manp. The arabinan termini of the arabinomannan were found to be extensively capped with mannosyl residues. The possibility that these polysaccharides contribute to the persistence of the tubercle bacillus in the macrophage by molecular mimicry is discussed. PMID:8297342

Structural features of the exocellular polysaccharides of Mycobacterium tuberculosis.

PubMed

Lemassu, A; Daffé, M

1994-01-15

The cell envelope which surrounds pathogenic mycobacteria is postulated to be a defence barrier against phagocytic cells and its outermost constituents have a tendency to accumulate in the culture medium. The present work demonstrates that the exocellular material of Mycobacterium tuberculosis contains large amounts of polysaccharides with only traces, if any at all, of lipids. Three types of polysaccharides were purified by anion-exchange and gel-filtration chromatography; all were found to be neutral compounds devoid of acyl substituents. They consisted of D-glucan, D-arabino-D-mannan and D-mannan, which were eluted from gel-filtration columns in positions corresponding to molecular masses of 123, 13 and 4 kDa respectively. Their predominant structural features were determined by the characterization of the per-O-methyl derivatives of enzymic, acetolysis and Smith-degradation products and by 1H- and 13C-n.m.r. spectroscopy of the purified polysaccharides, using mono- and two-dimensional homonuclear chemical-shift correlated spectroscopy and two-dimensional heteronuclear (1H/13C) spectroscopy. The glucan which represented up to 90% of the polysaccharides was composed of repeating units of five or six-->4-alpha-D-Glcp-1--> residues and a -->4-alpha-D-Glcp substituted at position 6 with an alpha-D-Glcp, indicating a glycogen-like highly branched structure not related to the so-called polysaccharide-II previously identified in tuberculin. The arabinomannan consisted of a mannan segment composed of a -->6-alpha-D-Man-1--> core substituted at some positions 2 with an alpha-D-Manp. The arabinan termini of the arabinomannan were found to be extensively capped with mannosyl residues. The possibility that these polysaccharides contribute to the persistence of the tubercle bacillus in the macrophage by molecular mimicry is discussed.

Individual neurophysiological profile in external effects investigation

NASA Astrophysics Data System (ADS)

Schastlivtseva, Daria; Tatiana Kotrovskaya, D..

Cortex biopotentials are the significant elements in human psychophysiological individuality. Considered that cortical biopotentials are diverse and individually stable, therefore there is the existence of certain dependence between the basic properties of higher nervous activity and cerebral bioelectric activity. The main purpose of the study was to reveal the individual neurophysiological profile and CNS initial functional state manifestation in human electroencephalogram (EEG) under effect of inert gases (argon, xenon, helium), hypoxia, pressure changes (0.02 and 0.2 MPa). We obtained 5-minute eyes closed background EEG on 19 scalp positions using Ag/AgCl electrodes mounted in an electrode cap. All EEG signals were re-referenced to average earlobes; Fast Furies Transformation analysis was used to calculate the relative power spectrum of delta-, theta-, alpha- and beta frequency band in artifact-free EEG. The study involved 26 healthy men who provided written informed consent, aged 20 to 35 years. Data obtained depend as individual EEG type and initial central nervous functional state as intensity, duration and mix of factors. Pronounced alpha rhythm in the raw EEG correlated with their adaptive capacity under studied factor exposure. Representation change and zonal distribution perversion of EEG alpha rhythm were accompanied by emotional instability, increased anxiety and difficulty adapting subjects. High power factor or combination factor with psychological and emotional or physical exertion minimizes individual EEG pattern.

Calcium binding to an elastic portion of connectin/titin filaments.

PubMed

Tatsumi, R; Maeda, K; Hattori, A; Takahashi, K

2001-01-01

Alpha-connectin/titin-1 exists as an elastic filament that links a thick filament with the Z-disk, keeping thick filaments centered within the sarcomere during force generation. We have shown that the connectin filament has an affinity for calcium ions and its binding site(s) is restricted to the beta-connectin/titin-2 portion. We now report the localization and the characterization of calcium-binding sites on beta-connectin. Purified beta-connectin was digested by trypsin into 1700- and 400-kDa fragments. which were then subjected to fluorescence calcium-binding assays. The 400-kDa fragment possesses calcium-binding activity; the binding constant was 1.0 x 10(7) M(-1) and the molar ratio of bound calcium ions to the 400-kDa fragment reached a maximum of 12 at a free calcium ion concentration of approximately 1.0 microM. Antibodies against the 400-kDa fragment formed a sharp dense stripe at the boundary of the A and the I bands, indicating that the calcium-binding domain constitutes the N-terminal region of beta-connectin, that is, the elastic portion of connectin filaments. Furthermore, we estimated the N-terminal location of beta-connectin of various origins (n = 26). Myofibrils were treated with a solution containing 0.1 mM CaCl2 and 70 microM leupeptin to split connectin filaments into beta-connectin and a subfragment, and chain weights of these polypeptides were estimated according to their mobility in 2% polyacrylamide slab gels. The subfragment exhibited a similar chain weight of 1200+/-33 kDa (mean+/-SD), while alpha- and beta-connectins were variable in size according to their origin. These results suggest that the apparent length of the 1200-kDa subfragment portion is almost constant in all instances, about 0.34 microm at the slack condition, therefore that the C-terminus of the 1200-kDa subfragment, that is, the N-terminus of the calcium-binding domain, is at the N2 line region of parent filaments in situ. Because the secondary structure of the 400-kDa fragment was changed by the binding of calcium ions, connectin filaments could be expected to alter their elasticity during the contraction-relaxation cycle of skeletal muscle.

Magnetostriction and corrosion studies in single crystals of iron-gallium alloys

NASA Astrophysics Data System (ADS)

Jayaraman, Tanjore V.

Iron-gallium alloys have an excellent combination of large low-field magnetostriction, good mechanical properties, low hysteresis, and relatively low cost. This dissertation focuses on the magneto striction and corrosion behaviors of single crystals of Fe-Ga alloys. In the first part, the variation of magnetostrictive coefficient: (3/2) lambda100, with composition and heat treatment conditions of Fe-Ga alloys, is examined. Single crystals with compositions Fe-15 at.% Ga, Fe-20 at.% Ga, and Fe-27.5 at.% Ga were obtained by (a) vertical Bridgman technique (DG) and (b) vertical Bridgman technique followed by long-term annealing (LTA) and quenching. Rapid quenching from a phase region improves the (3/2) lambda 100 value in these alloys. X-ray diffraction characterization showed for the first time the direct evidence of short-range ordering in these alloys. The second part reports the first study of alpha" ordering heat treatment on the elastic properties and magnetostriction of Fe-27.5 at.% Ga alloy single crystals. The elastic constants were measured using resonant ultrasound spectroscopy (RUS), and the elastic properties and magneto-elastic coupling constant were calculated. The (3/2) lambda100 and B1 values obtained for a phase were higher than alpha" phase. The third part examines the first study of corrosion behavior of as-cast FeGa and Fe-Ga-Al alloys in acidic, basic, and simulated seawater environments. Corrosion measurements were performed by Tafel scan and polarization resistance method and in general exhibited good corrosion resistance. The fourth part examines the first study of corrosion behavior of Fe-15 at.% Ga, Fe-20 at.% Ga, and Fe-27.5 at.% Ga DG and LTA alloy single crystals and the dependence of corrosion rates on the crystal orientations. The corrosion resistance was better in basic environments followed by simulated seawater and acidic environments. The fifth part examines the effect of magnetostriction on the corrosion behavior of [100]-oriented single crystal of Fe-20 at.% Ga alloy in acidic and simulated seawater solution, first study ever of this kind. Magnetostrictive strain introduced on the application of saturation magnetic field increased the corrosion rate of [100]-oriented Fe-20 at.% Ga alloy single crystal by 40% in 0.1M HCl and decreased the corrosion rate by 15% in 3.5 wt.% NaCl solution.

Interaction of insulin with colloidal ZnS quantum dots functionalized by various surface capping agents.

PubMed

Hosseinzadeh, Ghader; Maghari, Ali; Farniya, Seyed Morteza Famil; Keihan, Amir Homayoun; Moosavi-Movahedi, Ali A

2017-08-01

Interaction of quantum dots (QDs) and proteins strongly influenced by the surface characteristics of the QDs at the protein-QD interface. For a precise control of these surface-related interactions, it is necessary to improve our understanding in this field. In this regard, in the present work, the interaction between the insulin and differently functionalized ZnS quantum dots (QDs) were studied. The ZnS QDs were functionalized with various functional groups of hydroxyl (OH), carboxyl (COOH), amine (NH 2 ), and amino acid (COOH and NH 2 ). The effect of surface hydrophobicity was also studied by changing the alkyl-chain lengths of mercaptocarboxylic acid capping agents. The interaction between insulin and the ZnS QDs were investigated by fluorescence quenching, synchronous fluorescence, circular dichroism (CD), and thermal aggregation techniques. The results reveal that among the studied QDs, mercaptosuccinic acid functionalized QDs has the strongest interaction (∆G ° =-51.50kJ/mol at 310K) with insulin, mercaptoethanol functionalized QDs destabilize insulin by increasing the beta-sheet contents, and only cysteine functionalized QDs improves the insulin stability by increasing the alpha-helix contents of the protein, and. Our results also indicate that by increasing the alkyl-chain length of capping agents, due to an increase in hydrophobicity of the QDs surface, the beta-sheet contents of insulin increase which results in the enhancement of insulin instability. Copyright © 2017 Elsevier B.V. All rights reserved.

Venus 2004: east and west elongations and solar transit

NASA Astrophysics Data System (ADS)

McKim, R. J.; Blaxall, K.; Heath, A.

2007-04-01

The year 2004 was exceptional in producing the first solar transit of Venus since the late Victorian era. The bright aureole and atmospheric ring were re-observed, and the entire phenomenon was witnessed for the first time ever in hydrogen alpha light. Although routine observations throughout 2004 were unexceptional, patterns of visibility of bright and dark markings, cusp extensions and cusp-caps were recorded. No correlation was found between the latitude of the sub-Earth point and the visibility of either cusp-cap, with the S. cap predominating for most of the year. It was possible to accurately follow individual ultraviolet dark markings over many consecutive rotations, extending from the E. to W. elongations, and thereby to make a current measurement of the synodic atmospheric rotation period for the near-equatorial features: 3.996 ± 0.001 days. The true Ashen Light was reported visually on only a few occasions, but these correspond closely to times when infrared emission from the surface of the dark side was recorded in 1-micron waveband images. Some of the stable dark side albedo features were also visible upon the 1-micron images, and have been tentatively identified with known surface features. Infrared imaging at the same waveband showed little detail on the sunlit disk, but a few bright spots were sufficiently well observed to suggest a synodic rotation period close to 5.0 days, not atypical for the lower cloud decks.

The effects of elastic tubing-based resistance training compared with conventional resistance training in patients with moderate chronic obstructive pulmonary disease: a randomized clinical trial.

PubMed

Ramos, Ercy Mara Cipulo; de Toledo-Arruda, Alessandra Choqueta; Fosco, Luciana Cristina; Bonfim, Rafaela; Bertolini, Giovana Navarro; Guarnier, Flavia Alessandra; Cecchini, Rubens; Pastre, Carlos Marcelo; Langer, Daniel; Gosselink, Rik; Ramos, Dionei

2014-11-01

To investigate the effects of elastic tubing training compared with conventional resistance training on the improvement of functional exercise capacity, muscle strength, fat-free mass, and systemic inflammation in patients with chronic obstructive pulmonary disease. A prospective, randomized, eight-week clinical trial. The study was conducted in a university-based, outpatient, physical therapy clinic. A total of 49 patients with moderate chronic obstructive pulmonary disease. Participants were randomly assigned to perform elastic tubing training or conventional resistance training three times per week for eight weeks. The primary outcome measure was functional exercise capacity. The secondary outcome measures were peripheral muscle strength, health-related quality of life assessed by the Chronic Respiratory Disease Questionnaire (CRDQ), fat-free mass, and cytokine profile. After eight weeks, the mean distance covered during six minutes increased by 73 meters (±69) in the elastic tubing group and by 42 meters (±59) in the conventional group (p < 0.05). The muscle strength and quality of life improved in both groups (P < 0.05), with no significant differences between the groups. There was a trend toward an improved fat-free mass in both groups (P = 0.05). After the first and last sessions, there was an increase in interleukin 1β (IL-1β) and interleukin 10 (IL-10) in both groups, while tumour necrosis factor alpha (TNF-α) was stimulated only in the conventional training group. Elastic tubing training had a greater effect on functional exercise capacity than conventional resistance training. Both interventions were equally effective in improving muscle strength and quality of life. © The Author(s) 2014.

Global Low Frequency Protein Motions in Long-Range Allosteric Signaling

NASA Astrophysics Data System (ADS)

McLeish, Tom; Rogers, Thomas; Townsend, Philip; Burnell, David; Pohl, Ehmke; Wilson, Mark; Cann, Martin; Richards, Shane; Jones, Matthew

2015-03-01

We present a foundational theory for how allostery can occur as a function of low frequency dynamics without a change in protein structure. Elastic inhomogeneities allow entropic ``signalling at a distance.'' Remarkably, many globular proteins display just this class of elastic structure, in particular those that support allosteric binding of substrates (long-range co-operative effects between the binding sites of small molecules). Through multi-scale modelling of global normal modes we demonstrate negative co-operativity between the two cAMP ligands without change to the mean structure. Crucially, the value of the co-operativity is itself controlled by the interactions around a set of third allosteric ``control sites.'' The theory makes key experimental predictions, validated by analysis of variant proteins by a combination of structural biology and isothermal calorimetry. A quantitative description of allostery as a free energy landscape revealed a protein ``design space'' that identified the key inter- and intramolecular regulatory parameters that frame CRP/FNR family allostery. Furthermore, by analyzing naturally occurring CAP variants from diverse species, we demonstrate an evolutionary selection pressure to conserve residues crucial for allosteric control. The methodology establishes the means to engineer allosteric mechanisms that are driven by low frequency dynamics.

Service models and realization of differentiated services networks

NASA Astrophysics Data System (ADS)

Elizondo, Antonio J.; Garcia Osma, Maria L.; Einsiedler, Hans J.; Roth, Rudolf; Smirnov, Michael I.; Bartoli, Maurizio; Castelli, Paolo; Varga, Balazs; Krampell, Magnus

2001-07-01

Internet Service Providers need to offer Quality of Service (QoS) to fulfil the requirements of applications of their customers. Moreover, in a competitive market environment costs must be low. The selected service model must be effective and low in complexity, but it should still provide high quality and service differentiation, that the current Internet is not yet capable to support. The Differentiated Services (DiffServ) Architecture has been proposed for enabling a range of different Classes of Service (CoS). In the EURESCOM project P1006 several European service providers co-operated to examine various aspects involved in the introduction of service differentiation using the DiffServ approach. The project explored a set of service models for Expedited Forwarding (EF) and Assured Forwarding (AF) and identified requirements for network nodes. Besides, we addressed also measurement issues, charging and accounting issues. Special attention has been devoted to requirements of elastic traffic that adapts its sending rate to congestion state and available bandwidth. QoS mechanisms must prove Transmission Control Protocol (TCP) friendliness. TCP performance degrades under multiple losses. Since RED based queue management may still cause multiple discards, a modified marking scheme called Capped Leaky Bucket is proposed to improve the performance of elastic applications.

The crack problem in bonded nonhomogeneous materials

NASA Technical Reports Server (NTRS)

Erdogan, Fazil; Kaya, A. C.; Joseph, P. F.

1988-01-01

The plane elasticity problem for two bonded half planes containing a crack perpendicular to the interface was considered. The effect of very steep variations in the material properties near the diffusion plane on the singular behavior of the stresses and stress intensity factors were studied. The two materials were thus, assumed to have the shear moduli mu(o) and mu(o) exp (Beta x), x=0 being the diffusion plane. Of particular interest was the examination of the nature of stress singularity near a crack tip terminating at the interface where the shear modulus has a discontinuous derivative. The results show that, unlike the crack problem in piecewise homogeneous materials for which the singularity is of the form r/alpha, 0 less than alpha less than 1, in this problem the stresses have a standard square-root singularity regardless of the location of the crack tip. The nonhomogeneity constant Beta has, however, considerable influence on the stress intensity factors.

The crack problem in bonded nonhomogeneous materials

NASA Technical Reports Server (NTRS)

Erdogan, F.; Joseph, P. F.; Kaya, A. C.

1991-01-01

The plane elasticity problem for two bonded half planes containing a crack perpendicular to the interface was considered. The effect of very steep variations in the material properties near the diffusion plane on the singular behavior of the stresses and stress intensity factors were studied. The two materials were thus, assumed to have the shear moduli mu(o) and mu(o) exp (Beta x), x=0 being the diffusion plane. Of particular interest was the examination of the nature of stress singularity near a crack tip termination at the interface where the shear modulus has a discontinuous derivative. The results show that, unlike the crack problem in piecewise homogeneous materials for which the singularity is of the form r/alpha, 0 less than alpha less than 1, in this problem the stresses have a standard square-root singularity regardless of the location of the crack tip. The nonhomogeneity constant Beta has, however, considerable influence on the stress intensity factors.

Efficiencies of state and velocity-changing collisions of superthermal CN A(2)Pi with He, Ar, N(2) and O(2).

PubMed

Alagappan, Azhagammai; Ballingall, Iain; Costen, Matthew L; McKendrick, Kenneth G; Paterson, Grant

2007-02-14

Polarized laser photolysis of ICN is combined with saturated optical pumping to prepare state-selected CN Alpha(2)Pi (nu' = 4, J = 0.5, F(2), f) with a well-defined anisotropic superthermal speed distribution. The collisional evolution of the prepared state is observed by Doppler-resolved Frequency Modulated (FM) spectroscopy via stimulated emission on the CN Alpha(2)Pi-Chi(2)Sigma(+) (4,2) band. The phenomenological rate constants for removal of the prepared state in collisions with He, Ar, N(2) and O(2) are reported. The observed collision cross-sections are consistent with attractive forces contributing significantly for all the colliders with the exception of He. The collisional evolution of the prepared velocity distribution demonstrates that no significant back-transfer into the prepared level occurs, and that any elastic scattering is strongly in the forward hemisphere.

Effect of parylene C coating on the antibiocorrosive and mechanical properties of different magnesium alloys

NASA Astrophysics Data System (ADS)

Surmeneva, M. A.; Vladescu, A.; Cotrut, C. M.; Tyurin, A. I.; Pirozhkova, T. S.; Shuvarin, I. A.; Elkin, B.; Oehr, C.; Surmenev, R. A.

2018-01-01

In this paper, parylene C coating with the thickness of 2 μm was deposited on different magnesium alloy substrates (AZ31, WE43 and AZ91). The structure and phase composition of parylene C coating was analysed by Fourier transformed infrared (FTIR) spectroscopy and X-ray diffraction (XRD). In addition, extensive surface characterization was done using atomic force microscopy. The corrosion performance of polymer-coated magnesium alloys was investigated by electrochemical measurements in Hanks' balanced salts solution that simulates bodily fluids at 37 ± 0.5 °C. The depth-dependent mechanical properties including Young's modulus and nanohardness of parylene C films were investigated using nanoindentation technique. The effect of the penetration depth on the properties on nano- and microscale level have been described in detail. The percentage of elastic recovery was used to characterize the elastic properties of the polymeric coatings. The results of XRD showed (020) preferred orientation of the monoclinic unit cell of the alpha phase of parylene C. The parylene C revealed a semicrystalline structure with nanocrystalline blocks of 4.9 nm. The parylene C film shows a uniform surface morphology with a higher roughness level at micro and nanoscales compared to magnesium alloy surfaces. All of the uncoated substrates exhibited a low corrosion resistance compared to the coated samples, indicating that the corrosion resistance of the magnesium alloys could be improved by parylene C coating. The resulting average nanohardness and Young's modulus of the parylene C coatings deposited onto different substrates were in the range of 0.18-0.25 GPa and 4.19-5.14 GPa, respectively. Furthermore, a higher percentage of elastic recovery of the polymer coating indicated a higher elasticity as compared to the magnesium alloy surface. The polymer coating has revealed the ability to recover elastically. Therefore, parylene C coating can not only improve corrosion resistance, but also provide the ability to recover elastically, expanding the potential applications of this material to include various biointerface platforms.

Alpha-ketoglutarate stabilizes redox homeostasis and improves arterial elasticity in aged mice.

PubMed

Niemiec, T; Sikorska, J; Harrison, A; Szmidt, M; Sawosz, E; Wirth-Dzieciolowska, E; Wilczak, J; Pierzynowski, S

2011-02-01

The objective of this study was to evaluate the effect of α-ketoglutarate on redox state parameters and arterial elasticity in elderly mice. Mice in the control group were fed with standard diet, while the experimental animals received the diet supplemented either with calcium (Ca-AKG) or sodium salt of α-ketoglutarate (Na-AKG). The experimental animals were divided into 4 groups with 10 individuals in each: control I (12 months old), control II (2 months old), experimental group I fed with Ca-AKG (12 months old) and experimental group II fed with Na-AKG (12 months old). Mice treated with Ca-AKG as well as the control II animals demonstrated significantly higher level of total antioxidant status (TAS), comparing to the control I animals and those treated with Ca-AKG. Thiobarbituric acid reactive substances (TBARS) level in blood plasma was found significantly lower in young and Ca-AKG treated mice. TBARS liver concentration was significantly different in each examined group. The study also demonstrates the decrease in TBARS level in Ca-AKG treated animals. Treatment with Na-AKG significantly increased glutathione peroxidase activity and decreased the activity of superoxide dismutase. The presented results suggest that Ca-AKG protects the organism against the free radicals related elderly processes. The study presents also the effect of Ca-AKG treatment on arterial elastic characteristics in elderly mice. The beneficial effect of Ca-AKG on ageing organisms was confirmed via redox state stabilization and blood vessel elasticity improvement.

Brief report: reconstruction of joint hyaline cartilage by autologous progenitor cells derived from ear elastic cartilage.

PubMed

Mizuno, Mitsuru; Kobayashi, Shinji; Takebe, Takanori; Kan, Hiroomi; Yabuki, Yuichiro; Matsuzaki, Takahisa; Yoshikawa, Hiroshi Y; Nakabayashi, Seiichiro; Ik, Lee Jeong; Maegawa, Jiro; Taniguchi, Hideki

2014-03-01

In healthy joints, hyaline cartilage covering the joint surfaces of bones provides cushioning due to its unique mechanical properties. However, because of its limited regenerative capacity, age- and sports-related injuries to this tissue may lead to degenerative arthropathies, prompting researchers to investigate a variety of cell sources. We recently succeeded in isolating human cartilage progenitor cells from ear elastic cartilage. Human cartilage progenitor cells have high chondrogenic and proliferative potential to form elastic cartilage with long-term tissue maintenance. However, it is unknown whether ear-derived cartilage progenitor cells can be used to reconstruct hyaline cartilage, which has different mechanical and histological properties from elastic cartilage. In our efforts to develop foundational technologies for joint hyaline cartilage repair and reconstruction, we conducted this study to obtain an answer to this question. We created an experimental canine model of knee joint cartilage damage, transplanted ear-derived autologous cartilage progenitor cells. The reconstructed cartilage was rich in proteoglycans and showed unique histological characteristics similar to joint hyaline cartilage. In addition, mechanical properties of the reconstructed tissues were higher than those of ear cartilage and equal to those of joint hyaline cartilage. This study suggested that joint hyaline cartilage was reconstructed from ear-derived cartilage progenitor cells. It also demonstrated that ear-derived cartilage progenitor cells, which can be harvested by a minimally invasive method, would be useful for reconstructing joint hyaline cartilage in patients with degenerative arthropathies. © AlphaMed Press.

A-thermal elastic behavior of silicate glasses.

PubMed

Rabia, Mohammed Kamel; Degioanni, Simon; Martinet, Christine; Le Brusq, Jacques; Champagnon, Bernard; Vouagner, Dominique

2016-02-24

Depending on the composition of silicate glasses, their elastic moduli can increase or decrease as function of the temperature. Studying the Brillouin frequency shift of these glasses versus temperature allows the a-thermal composition corresponding to an intermediate glass to be determined. In an intermediate glass, the elastic moduli are independent of the temperature over a large temperature range. For sodium alumino-silicate glasses, the a-thermal composition is close to the albite glass (NaAlSi3O8). The structural origin of this property is studied by in situ high temperature Raman scattering. The structure of the intermediate albite glass and of silica are compared at different temperatures between room temperature and 600 °C. When the temperature increases, it is shown that the high frequency shift of the main band at 440 cm(-1) in silica is a consequence of the cristobalite-like alpha-beta transformation of 6-membered rings. This effect is stronger in silica than bond elongation (anharmonic effects). As a consequence, the elastic moduli of silica increase as the temperature increases. In the albite glass, the substitution of 25% of Si(4+) ions by Al(3+) and Na(+) ions decreases the proportion of SiO2 6-membered rings responsible for the silica anomaly. The effects of the silica anomaly balance the anharmonicity in albite glass and give rise to an intermediate a-thermal glass. Different networks, formers or modifiers, can be added to produce different a-thermal glasses with useful mechanical or chemical properties.

Orientation dependence of grain-boundary energy in metals in the view of a pseudoheterophase dislocation core model

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

Missol, W.

A new dislocation model for symmetric tilt grain boundaries was developed as a basis for deriving the quantitative dependence of grain-boundary energy upon misorientation angle in the form of an expression similar to that given by Read and Shockley (Phys. Rev. 78: 275(1950)). The range of applicability of this equation was extended to over 20 degrees. A comparison of theory and experiment was made for Bi, Ag, Cu, and Fe--Si 3 percent in the teen-degree range of misorientation angles and for Au, ..cap alpha..-Fe, Mo, and W in the high-angle range.

Development and fabrication of an advanced liquid cooling garment

NASA Technical Reports Server (NTRS)

Hixon, C. W.

1978-01-01

A tube/fin concept liquid cooling garment head cooler was developed, fabricated and delivered to NASA-ARC. The head cooler was fabricated from polyurethane film which sandwiches the transport fluid tubing and a thermally conductive fin material. The head cooler garment is sewn to form a skull cap and covered with a comfort liner. In addition, two Neonate heating garments were fabricated and supplied to NASA for further finishing and use in medical tests. The resulting garment is flexible, elastic and conforms to the head comfortably. Tests on a tube/fin element of identical construction as the head cooler demonstrated good thermal effectiveness. Use of commercially available materials and development of relatively simple fabrication techniques give the potential for a low garment cost.

Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

PubMed

Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

2010-10-01

The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cements

The jump-off velocity of an impulsively loaded spherical shell

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

Chabaud, Brandon M.; Brock, Jerry S.

2012-04-13

We consider a constant temperature spherical shell of isotropic, homogeneous, linearly elastic material with density {rho} and Lame coefficients {lambda} and {mu}. The inner and outer radii of the shell are r{sub i} and r{sub o}, respectively. We assume that the inside of the shell is a void. On the outside of the shell, we apply a uniform, time-varying pressure p(t). We also assume that the shell is initially at rest. We want to compute the jump-off time and velocity of the pressure wave, which are the first time after t = 0 at which the pressure wave from themore » outer surface reaches the inner surface. This analysis computes the jump-off velocity and time for both compressible and incompressible materials. This differs substantially from [3], where only incompressible materials are considered. We will consider the behavior of an impulsively loaded, exponentially decaying pressure wave p(t) = P{sub 0{sup e}}{sup -{alpha}t}, where {alpha} {ge} 0. We notice that a constant pressure wave P(t) = P{sub 0} is a special case ({alpha} = 0) of a decaying pressure wave. Both of these boundary conditions are considered in [3].« less

A trial of prazosin for combat trauma PTSD with nightmares in active-duty soldiers returned from Iraq and Afghanistan.

PubMed

Raskind, Murray A; Peterson, Kris; Williams, Tammy; Hoff, David J; Hart, Kimberly; Holmes, Hollie; Homas, Dallas; Hill, Jeffrey; Daniels, Colin; Calohan, Jess; Millard, Steven P; Rohde, Kirsten; O'Connell, James; Pritzl, Denise; Feiszli, Kevin; Petrie, Eric C; Gross, Christopher; Mayer, Cynthia L; Freed, Michael C; Engel, Charles; Peskind, Elaine R

2013-09-01

The authors conducted a 15-week randomized controlled trial of the alpha-1 adrenoreceptor antagonist prazosin for combat trauma nightmares, sleep quality, global function, and overall symptoms in active-duty soldiers with posttraumatic stress disorder (PTSD) returned from combat deployments to Iraq and Afghanistan. Sixty-seven soldiers were randomly assigned to treatment with prazosin or placebo for 15 weeks. Drug was titrated based on nightmare response over 6 weeks to a possible maximum dose of 5 mg midmorning and 20 mg at bedtime for men and 2 mg midmorning and 10 mg at bedtime for women. Mean achieved bedtime doses were 15.6 mg of prazosin (SD=6.0) and 18.8 mg of placebo (SD=3.3) for men and 7.0 mg of prazosin (SD=3.5) and 10.0 mg of placebo (SD=0.0) for women. Mean achieved midmorning doses were 4.0 mg of prazosin (SD=1.4) and 4.8 mg of placebo (SD=0.8) for men and 1.7 mg of prazosin (SD=0.5) and 2.0 mg of placebo (SD=0.0) mg for women. Primary outcome measures were the nightmare item of the Clinician-Administered PTSD Scale (CAPS), the Pittsburgh Sleep Quality Index, and the change item of the Clinical Global Impressions Scale anchored to functioning. Secondary outcome measures were the 17-item CAPS, the Hamilton Depression Rating Scale, the Patient Health Questionnaire-9, and the Quality of Life Index. Maintenance psychotropic medications and supportive psychotherapy were held constant. Prazosin was effective for trauma nightmares, sleep quality, global function, CAPS score, and the CAPS hyperarousal symptom cluster. Prazosin was well tolerated, and blood pressure changes did not differ between groups. Prazosin is effective for combat-related PTSD with trauma nightmares in active-duty soldiers, and benefits are clinically meaningful. Substantial residual symptoms suggest that studies combining prazosin with effective psychotherapies might demonstrate further benefit.

Differences in elasticity of vinculin-deficient F9 cells measured by magnetometry and atomic force microscopy

NASA Technical Reports Server (NTRS)

Goldmann, W. H.; Galneder, R.; Ludwig, M.; Xu, W.; Adamson, E. D.; Wang, N.; Ezzell, R. M.; Ingber, D. E. (Principal Investigator)

1998-01-01

We have investigated a mouse F9 embryonic carcinoma cell line, in which both vinculin genes were inactivated by homologous recombination, that exhibits defective adhesion and spreading [Coll et al. (1995) Proc. Natl. Acad. Sci. USA 92, 9161-9165]. Using a magnetometer and RGD-coated magnetic microbeads, we measured the local effect of loss and replacement of vinculin on mechanical force transfer across integrins. Vinculin-deficient F9Vin(-/-) cells showed a 21% difference in relative stiffness compared to wild-type cells. This was restored to near wild-type levels after transfection and constitutive expression of increasing amounts of vinculin into F9Vin(-/-) cells. In contrast, the transfection of vinculin constructs deficient in amino acids 1-288 (containing the talin- and alpha-actinin-binding site) or substituting tyrosine for phenylalanine (phosphorylation site, amino acid 822) in F9Vin(-/-) cells resulted in partial restoration of stiffness. Using atomic force microscopy to map the relative elasticity of entire F9 cells by 128 x 128 (n = 16,384) force scans, we observed a correlation with magnetometer measurements. These findings suggest that vinculin may promote cell adhesions and spreading by stabilizing focal adhesions and transferring mechanical stresses that drive cytoskeletal remodeling, thereby affecting the elastic properties of the cell.

Hemispheric dichotomy in lithosphere growth on Mars caused by differences in crustal composition

NASA Astrophysics Data System (ADS)

Thiriet, M.; Michaut, C.; Breuer, D.

2016-12-01

The surface dichotomy is the most striking feature of Mars. The Northern hemisphere is covered by extensive lava plains and is lower in altitude than the South which has higher and sharper reliefs and is more craterized and older than the North. Recent studies have suggested that this bimodal distribution of altitudes could be due to the existence of a buried felsic component similar to the terrestrial continental crust in the Southern hemisphere. The presence of a large buried component of evolved composition might imply an enrichment in incompatible radioactive elements. The thermal surface properties of the two hemispheres also seem to differ; the South shows fine-particulate materials probably resulting from explosive volcanism, while the Northern lava flows are more consolidated and characterized by a higher thermal conductivity. Using a parameterized convection model with a stagnant lid, we computed the thermal evolution and lithosphere growth of Mars accounting for potential differences in the thermal parameters characterizing the Northern and Southern crusts. We find that a stronger enrichment in radioactive elements and a lower surface conductivity in the South can cause a significant difference in elastic thickness of the lithosphere in between both hemispheres, with an elastic lithosphere thicker in the North by several tens of kilometers today. This result might explain the large and still unexplained difference in lithosphere elastic thickness estimated below the two polar caps, which is about 300 km in the North and only 140 km in the South. Assuming a crust in the Northern hemisphere with a thickness of 40 km, a density of 3000 kg/m3 and an enrichment factor in radioactive elements of 5 relative to the primitive mantle, Monte Carlo inversions show that the Southern crust requires a thickness of >60 km, a density between 2700 and 3000 kg/m3 and an enrichment factor of 13-20 to explain such a difference in lithosphere elastic thickness.

The inverted pendulum model of bipedal standing cannot be stabilized through direct feedback of force and contractile element length and velocity at realistic series elastic element stiffness.

PubMed

van Soest, A J Knoek; Rozendaal, Leonard A

2008-07-01

Control of bipedal standing is typically analyzed in the context of a single-segment inverted pendulum model. The stiffness K (SE) of the series elastic element that transmits the force generated by the contractile elements of the ankle plantarflexors to the skeletal system has been reported to be smaller in magnitude than the destabilizing gravitational stiffness K ( g ). In this study, we assess, in case K (SE) + K ( g ) < 0, if bipedal standing can be locally stable under direct feedback of contractile element length, contractile element velocity (both sensed by muscle spindles) and muscle force (sensed by Golgi tendon organs) to alpha-motoneuron activity. A theoretical analysis reveals that even though positive feedback of force may increase the stiffness of the muscle-tendon complex to values well over the destabilizing gravitational stiffness, dynamic instability makes it impossible to obtain locally stable standing under the conditions assumed.

Hydrogen absorption by thin Pd/Nb films deposited on glass

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

Reisfeld, G.; Jisrawi, N.M.; Ruckman, M.W.

Hydrogen absorption by 200{endash}2000-A-thick Pd-capped Nb films, between 5 and 110{degree}C, was studied by simultaneous four-probe resistivity and volumetric measurements. The resistivity as a function of hydrogen concentration was measured while charging the films with hydrogen, and was used to compute the change in hydrogen concentration in the film, during the reaction with oxygen. For the thinnest films (200 A thick), the hydrogen charging and discharging curves indicate that a first-order gas-liquid-like phase transition with a {ital T}{sub {ital c}} of 70{endash}75{degree}C takes place. The H-Nb phase diagram for the 200-A film looks like the H/bulk Nb {alpha}-{alpha}{prime} phase diagrammore » which has a higher {ital T}{sub {ital c}} (173{degree}C). We attribute the substantial modifications of the film{close_quote}s phase diagram to the clamping of the Nb film at its interfaces with glass and Pd and to the nanostructure of the films. {copyright} {ital 1996 The American Physical Society.}« less

Canine candidate genes for dilated cardiomyopathy: annotation of and polymorphic markers for 14 genes.

PubMed

Wiersma, Anje C; Leegwater, Peter Aj; van Oost, Bernard A; Ollier, William E; Dukes-McEwan, Joanna

2007-10-19

Dilated cardiomyopathy is a myocardial disease occurring in humans and domestic animals and is characterized by dilatation of the left ventricle, reduced systolic function and increased sphericity of the left ventricle. Dilated cardiomyopathy has been observed in several, mostly large and giant, dog breeds, such as the Dobermann and the Great Dane. A number of genes have been identified, which are associated with dilated cardiomyopathy in the human, mouse and hamster. These genes mainly encode structural proteins of the cardiac myocyte. We present the annotation of, and marker development for, 14 of these genes of the dog genome, i.e. alpha-cardiac actin, caveolin 1, cysteine-rich protein 3, desmin, lamin A/C, LIM-domain binding factor 3, myosin heavy polypeptide 7, phospholamban, sarcoglycan delta, titin cap, alpha-tropomyosin, troponin I, troponin T and vinculin. A total of 33 Single Nucleotide Polymorphisms were identified for these canine genes and 11 polymorphic microsatellite repeats were developed. The presented polymorphisms provide a tool to investigate the role of the corresponding genes in canine Dilated Cardiomyopathy by linkage analysis or association studies.

Leiomodin and tropomodulin in smooth muscle

NASA Technical Reports Server (NTRS)

Conley, C. A.

2001-01-01

Evidence is accumulating to suggest that actin filament remodeling is critical for smooth muscle contraction, which implicates actin filament ends as important sites for regulation of contraction. Tropomodulin (Tmod) and smooth muscle leiomodin (SM-Lmod) have been found in many tissues containing smooth muscle by protein immunoblot and immunofluorescence microscopy. Both proteins cofractionate with tropomyosin in the Triton-insoluble cytoskeleton of rabbit stomach smooth muscle and are solubilized by high salt. SM-Lmod binds muscle tropomyosin, a biochemical activity characteristic of Tmod proteins. SM-Lmod staining is present along the length of actin filaments in rat intestinal smooth muscle, while Tmod stains in a punctate pattern distinct from that of actin filaments or the dense body marker alpha-actinin. After smooth muscle is hypercontracted by treatment with 10 mM Ca(2+), both SM-Lmod and Tmod are found near alpha-actinin at the periphery of actin-rich contraction bands. These data suggest that SM-Lmod is a novel component of the smooth muscle actin cytoskeleton and, furthermore, that the pointed ends of actin filaments in smooth muscle may be capped by Tmod in localized clusters.

Heat-transfer test results for a .0275-scale space shuttle external tank with a 10 deg/40 deg double cone-ogive nose in the NASA/AMES 3.5-foot hypersonic wind tunnel (FH14), volume 2

NASA Technical Reports Server (NTRS)

Carroll, H. R.

1977-01-01

A .0275 scale forebody model of the new baseline configuration of the space shuttle external tank vent cap configuration was tested to determine the flow field due to the double cone configuration. The tests were conducted in a 3.5 foot hypersonic wind tunnel at alpha = -5 deg, -4.59 deg, 0 deg, 5 deg, and 10 deg; beta = 0 deg, -3 deg, -5.51 deg, -6 deg, -9 deg, and +6 deg; nominal freestream Reynolds numbers per foot of 1.5 x 1 million, 3.0 x 1 million, and 5.0 x 1 million; and a nominal Mach number of 5. Separation and reattached flow from thermocouple data, shadowgraphs, and oil flows indicate that separation begins about 80% from the tip of the 10 deg cone, then reattaches on the vent cap and produces fully turbulent flow over most of the model forebody. The hardware disturbs the flow over a much larger area than present TPS application has assumed. A correction to the flow disturbance was experimentally suggested from the results of an additional test run.

Evaluating the Quality of Competency Assessment in Pharmacy: A Framework for Workplace Learning.

PubMed

Shah, Shailly; McLaughlin, Jacqueline E; Eckel, Stephen F; Mangun, Jesica; Hawes, Emily

2016-01-19

Demonstration of achieved competencies is critical in the pharmacy workplace. The purpose of this study was to evaluate the quality of the competency assessment program for pharmacy residents at an academic medical center. The competency assessment program (CAP) survey is a validated, 48-item instrument that evaluates the quality of an assessment program based on 12 criteria, each measured by four questions on a scale of 0 to 100. The CAP was completed by residents ( n = 23) and preceptors ( n = 28) from the pharmacy residency program between 2010 and 2013. Results were analyzed using descriptive statistics, Cronbach's alpha, and non-parametric tests. Educational Consequences was the only quality criteria falling below the standard for "good quality." Participants that completed residency training elsewhere rated the Comparability (0.04) and Meaningfulness (0.01) of the assessment program higher than those that completed residency at the academic medical center. There were no significant differences between resident and preceptor scores. Overall, the quality of the assessment program was rated highly by residents and preceptors. The process described here provides a useful framework for understanding the quality of workplace learning assessments in pharmacy practice.

[Role of rostral ventrolateral medulla in the pressor response to intraventricular (4th) injection of substance P].

PubMed

Zhang, X H; Ni, H

1998-04-01

Experiments were done in rabbits anaesthetized with urethane and immobilized under artificial respiration. It was found that substance P (SP, 0.8 ng/kg dissolved in 100 microliters artificial cerebro-spinal fluid, CSF) injected into the 4th ventricle induced either a rise or a drop of pulmonary arterial pressure (PAP) with predominated pressor response. In addition, a rise in carotid arterial pressure (CAP) and reduction in heart rate (HR) were also observed, whereas no significant alteration in PAP, CAP and HR was observed. Microinjection of SP receptor antagonist [D-Pro2, D-Phe7, D-Trp9]--SP (5-10 ng dissolved in 0.5 microliter CSF) or phentolamine (2-3 micrograms dissolved in 0.5 microliter CSF) into the bilateral rostral ventrolateral medulla (rVLM) prior to intraventricular injection of SP could block the SP-induced pressor responses in pulmonary and carotid arteries, while microinjection of SP receptor antagonist or phentolamine into bilateral caudal ventrolateral medulla (cVLM) at the same dosage had no effect. The results show that SP-induced pulmonary and carotid pressor responses may be mediated through SP-receptor and alpha-adrenergic receptors in the rostral ventro-lateral medulla (rVLM).

Alterations in the function of circulating mononuclear cells derived from patients with Crohn’s disease treated with mastic

PubMed Central

Kaliora, Andriana C; Stathopoulou, Maria G; Triantafillidis, John K; Dedoussis, George VZ; Andrikopoulos, Nikolaos K

2007-01-01

AIM: To assess the effects of mastic administration on cytokine production of circulating mononuclear cells of patients with active Crohn's disease (CD). METHODS: The study was conducted in patients with established mildly to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Recruited to a 4 wk treatment with mastic caps (6 caps/d,0.37 g/cap) were 10 patients and 8 controls, all of who successfully completed the protocol. Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), macrophage migration inhibitory factor (MIF) and intracellular antioxidant glutathione (GSH) were evaluated in peripheral blood mononuclear cells (PBMC) before and after treatment. RESULTS: Treating CD patients with mastic resulted in the reduction of TNF-α secretion (2.1 ± 0.9 ng/mL vs 0.5 ± 0.4 ng/mL, P = 0.028). MIF release was significantly increased (1.2 ± 0.4 ng/mL vs 2.5 ± 0.7 ng/mL, P = 0.026) meaning that random migration and chemotaxis of monocytes/macrophages was inhibited. No significant changes were observed in IL-6, MCP-1 and GSH concentrations. CONCLUSION: This study shows that mastic acts as an immunomodulator on PBMC, acting as a TNF-α inhibitor and a MIF stimulator. Although further double-blind, placebo-controlled studies in a large number of patients is required to clarify the role of this natural product, this finding provides strong evidence that mastic might be an important regulator of immunity in CD. PMID:18023095

Recoil /sup 18/F chemistry. XI. High pressure investigation of 1,1-difluoroethane

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

Manning, R.G.; Root, J.W.

1980-06-15

Nuclear recoil /sup 18/F reactions in CH/sub 3/CHF/sub 2/ have been investigated throughout the effective pressure range 0.3--190 atm. The principal reaction channel is F-to-HF abstraction for which the combined yield from quasithermal and energetic processes in the presence of 5 mole% H/sub 2/S additive is 83.4% +- 0.2%. A reaction mechanism is proposed that involves the organic product forming channels F-for-F, F-for-..cap alpha..H, F-for-..beta..H, F-for-CH/sub 3/ and F-for-CHF/sub 2/. The results are compared with those reported for the /sup 18/F+CH/sub 3/CF/sub 3/ system.

Angular distributions of the protons in the reaction. pi. /sup +/+Xe. -->. p+xxx at 2. 34 GeV/c as a background for the shock-wave effect

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

Slowinski, B.; Strugalski, Z.

1977-02-20

Results are presented of an analysis of the angular distributions of protons with E/sub p/> or =30 MeV emitted with different numbers of secondary charged particles in ..pi../sup +/+Xe interactions at 2.34 GeV/c. The obtained distributions are compared with the analogous characteristics of the protons emitted in collisions of protons or ..cap alpha.. particles with heavy emulsion nuclei and with lead at 70 and 17 GeV/c. It is concluded that the investigated distributions reveal no irregularities capable of attesting to a noticable role of the shock-wave mechanism in the target nuclei.

Optical micromachined ultrasound transducers (OMUT)--a new approach for high-frequency transducers.

PubMed

Tadayon, Mohammad Amin; Ashkenazi, Shai

2013-09-01

The sensitivity and reliability of piezoelectric ultrasound transducers severely degrade in applications requiring high frequency and small element size. Alternative technologies such as capacitive micromachined ultrasound transducers (CMUT) and optical sensing and generation of ultrasound have been proposed and studied for several decades. In this paper, we present a new type of device based on optical micromachined ultrasound transducer (OMUT) technology. OMUTs rely on microfabrication techniques to construct micrometerscale air cavities capped by an elastic membrane. A modified photoresist bonding process has been developed to facilitate the fabrication of these devices. We will describe the design, fabrication, and testing of prototype OMUT devices which implement a receive-only function. Future design modifications are proposed for incorporating complete transmit¿receive functionality in a single element.

Copper, Aluminum and Nickel: A New Monocrystalline Orthodontic Alloy

NASA Astrophysics Data System (ADS)

Wierenga, Mark

Introduction: This study was designed to evaluate, via tensile and bend testing, the mechanical properties of a newly-developed monocrystalline orthodontic archwire comprised of a blend of copper, aluminum, and nickel (CuAlNi). Methods: The sample was comprised of three shape memory alloys; CuAlNi, copper nickel titanium (CuNiTi), and nickel titanium (NiTi); from various orthodontic manufacturers in both 0.018" round and 0.019" x 0.025" rectangular dimensions. Additional data was gathered for similarly sized stainless steel and beta-titanium archwires as a point of reference for drawing conclusions about the relative properties of the archwires. Measurements of loading and unloading forces were recorded in both tension and deflection testing. Repeated-measure ANOVA (alpha= 0.05) was used to compare loading and unloading forces across wires and one-way ANOVA (alpha= 0.05) was used to compare elastic moduli and hysteresis. To identify significant differences, Tukey post-hoc comparisons were performed. Results: The modulus of elasticity, deflection forces, and hysteresis profiles of CuAlNi were significantly different than the other superelastic wires tested. In all tests, CuAlNi had a statistically significant lower modulus of elasticity compared to the CuNiTi and NiTi wires (P <0.0001). The CuAlNi wire exhibited significantly lower loading and unloading forces than any other wire tested. In round wire tensile tests, loading force at all deflections was significantly lower for CuAlNi than CuNiTi or NiTi (P <0.0001). In tensile testing, the CuAlNi alloy was able to recover from a 7 mm extension (10% elongation) without permanent deformation and with little to no loss in force output. In large-deflection bend tests at 4, 5, and 6 mm deflection, CuAlNi showed the significantly lowest loading forces across the three wire materials (P <0.0001). The NiTi wires showed up to 12 times the amount of energy loss due to hysteresis compared to CuAlNi. CuAlNi showed a hysteresis loss that was significantly less than any other wire tested in this study (P <0.0001). Conclusions: The relatively constant force delivered for a long period of time during the deactivation of this wire, the minimal hysteresis loss, the low force output in deflection, and the relatively low modulus of elasticity suggest that CuAlNi wires should be considered an important material addition to orthodontic metallurgy.

Strain tensor selection and the elastic theory of incompatible thin sheets.

PubMed

Oshri, Oz; Diamant, Haim

2017-05-01

The existing theory of incompatible elastic sheets uses the deviation of the surface metric from a reference metric to define the strain tensor [Efrati et al., J. Mech. Phys. Solids 57, 762 (2009)JMPSA80022-509610.1016/j.jmps.2008.12.004]. For a class of simple axisymmetric problems we examine an alternative formulation, defining the strain based on deviations of distances (rather than distances squared) from their rest values. While the two formulations converge in the limit of small slopes and in the limit of an incompressible sheet, for other cases they are found not to be equivalent. The alternative formulation offers several features which are absent in the existing theory. (a) In the case of planar deformations of flat incompatible sheets, it yields linear, exactly solvable, equations of equilibrium. (b) When reduced to uniaxial (one-dimensional) deformations, it coincides with the theory of extensible elastica; in particular, for a uniaxially bent sheet it yields an unstrained cylindrical configuration. (c) It gives a simple criterion determining whether an isometric immersion of an incompatible sheet is at mechanical equilibrium with respect to normal forces. For a reference metric of constant positive Gaussian curvature, a spherical cap is found to satisfy this criterion except in an arbitrarily narrow boundary layer.

Analysis of tablet compaction. I. Characterization of mechanical behavior of powder and powder/tooling friction.

PubMed

Cunningham, J C; Sinka, I C; Zavaliangos, A

2004-08-01

In this first of two articles on the modeling of tablet compaction, the experimental inputs related to the constitutive model of the powder and the powder/tooling friction are determined. The continuum-based analysis of tableting makes use of an elasto-plastic model, which incorporates the elements of yield, plastic flow potential, and hardening, to describe the mechanical behavior of microcrystalline cellulose over the range of densities experienced during tableting. Specifically, a modified Drucker-Prager/cap plasticity model, which includes material parameters such as cohesion, internal friction, and hydrostatic yield pressure that evolve with the internal state variable relative density, was applied. Linear elasticity is assumed with the elastic parameters, Young's modulus, and Poisson's ratio dependent on the relative density. The calibration techniques were developed based on a series of simple mechanical tests including diametrical compression, simple compression, and die compaction using an instrumented die. The friction behavior is measured using an instrumented die and the experimental data are analyzed using the method of differential slices. The constitutive model and frictional properties are essential experimental inputs to the finite element-based model described in the companion article. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2022-2039, 2004

Strain tensor selection and the elastic theory of incompatible thin sheets

NASA Astrophysics Data System (ADS)

Oshri, Oz; Diamant, Haim

2017-05-01

The existing theory of incompatible elastic sheets uses the deviation of the surface metric from a reference metric to define the strain tensor [Efrati et al., J. Mech. Phys. Solids 57, 762 (2009), 10.1016/j.jmps.2008.12.004]. For a class of simple axisymmetric problems we examine an alternative formulation, defining the strain based on deviations of distances (rather than distances squared) from their rest values. While the two formulations converge in the limit of small slopes and in the limit of an incompressible sheet, for other cases they are found not to be equivalent. The alternative formulation offers several features which are absent in the existing theory. (a) In the case of planar deformations of flat incompatible sheets, it yields linear, exactly solvable, equations of equilibrium. (b) When reduced to uniaxial (one-dimensional) deformations, it coincides with the theory of extensible elastica; in particular, for a uniaxially bent sheet it yields an unstrained cylindrical configuration. (c) It gives a simple criterion determining whether an isometric immersion of an incompatible sheet is at mechanical equilibrium with respect to normal forces. For a reference metric of constant positive Gaussian curvature, a spherical cap is found to satisfy this criterion except in an arbitrarily narrow boundary layer.

Electronic shot noise in fractal conductors.

PubMed

Groth, C W; Tworzydło, J; Beenakker, C W J

2008-05-02

By solving a master equation in the Sierpiński lattice and in a planar random-resistor network, we determine the scaling with size L of the shot noise power P due to elastic scattering in a fractal conductor. We find a power-law scaling P proportional, variantL;{d_{f}-2-alpha}, with an exponent depending on the fractal dimension d_{f} and the anomalous diffusion exponent alpha. This is the same scaling as the time-averaged current I[over ], which implies that the Fano factor F=P/2eI[over ] is scale-independent. We obtain a value of F=1/3 for anomalous diffusion that is the same as for normal diffusion, even if there is no smallest length scale below which the normal diffusion equation holds. The fact that F remains fixed at 1/3 as one crosses the percolation threshold in a random-resistor network may explain recent measurements of a doping-independent Fano factor in a graphene flake.

Scattering of 42 MeV alpha particles from copper-65

NASA Technical Reports Server (NTRS)

Stewart, W. M.; Seth, K. K.

1973-01-01

Beams of 42-MeV alpha particles were elastically and inelastically scattered from Cu-65 in an attempt to excite states which may be described in terms of an excited core model. Angular distributions were measured for 17 excited states. Seven of the excited states had angular distributions similar to a core quadrupole excitation and eight of the excited states had angular distributions similar to a core octupole excitation. The excited state at 2.858 MeV had an angular distribution which suggests that it may have results from the particle coupling to a two-phonon core state. An extended particle-core coupling calculation was performed and the predicted energy levels and reduced transition probabilities compared to the experimental data. The low lying levels are described quite well and the wavefunctions of these states explain the large spectroscopic factors measured in stripping reactions. For Cu-65 the coupling of the particle to the core is no larger weak as in the simpler model, and configuration mixing results.

Xmsx-1 modifies mesodermal tissue pattern along dorsoventral axis in Xenopus laevis embryo.

PubMed

Maeda, R; Kobayashi, A; Sekine, R; Lin, J J; Kung, H; Maéno, M

1997-07-01

This study analyzes the expression and the function of Xenopus msx-1 (Xmsx-1) in embryos, in relation to the ventralizing activity of bone morphogenetic protein-4 (BMP-4). Expression of Xmsx-1 was increased in UV-treated ventralized embryos and decreased in LiCl-treated dorsalized embryos at the neurula stage (stage 14). Whole-mount in situ hybridization analysis showed that Xmsx-1 is expressed in marginal zone and animal pole areas, laterally and ventrally, but not dorsally, at mid-gastrula (stage 11) and late-gastrula (stage 13) stages. Injection of BMP-4 RNA, but not activin RNA, induced Xmsx-1 expression in the dorsal marginal zone at the early gastrula stage (stage 10+), and introduction of a dominant negative form of BMP-4 receptor RNA suppressed Xmsx-1 expression in animal cap and ventral marginal zone explants at stage 14. Thus, Xmsx-1 is a target gene specifically regulated by BMP-4 signaling. Embryos injected with Xmsx-1 RNA in dorsal blastomeres at the 4-cell stage exhibited a ventralized phenotype, with microcephaly and swollen abdomen. Histological observation and immunostaining revealed that these embryos had a large block of muscle tissue in the dorsal mesodermal area instead of notochord. On the basis of molecular marker analysis, however, the injection of Xmsx-1 RNA did not induce the expression of alpha-globin, nor reduce cardiac alpha-actin in dorsal marginal zone explants. Furthermore, a significant amount of alpha-actin was induced and alpha-globin was turned off in the ventral marginal zone explants injected with Xmsx-1. These results indicated that Xmsx-1 is a target gene of BMP-4 signaling, but possesses a distinct activity on dorsal-ventral patterning of mesodermal tissues.

Measurements of ionic structure in shock compressed lithium hydride from ultrafast x-ray Thomson scattering.

PubMed

Kritcher, A L; Neumayer, P; Brown, C R D; Davis, P; Döppner, T; Falcone, R W; Gericke, D O; Gregori, G; Holst, B; Landen, O L; Lee, H J; Morse, E C; Pelka, A; Redmer, R; Roth, M; Vorberger, J; Wünsch, K; Glenzer, S H

2009-12-11

We present the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. Laser-compressed lithium-hydride samples are well characterized by inelastic Compton and plasmon scattering of a K-alpha x-ray probe providing independent measurements of temperature and density. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for the screening of ion-ion interactions.

Metallographic study of metallic fragment of lunar surface material

NASA Technical Reports Server (NTRS)

Mints, R. I.; Petukhova, T. M.; Ivanov, A. V.

1974-01-01

A high precision investigation of a metallic fragment from the lunar material returned by the Soviet Luna 16 automatic station revealed three characteristic temperature intervals with different kinetics of solid solution decomposition. The following were found in the structure of the iron-nickel-cobalt alloy: (1) delta-phase and alpha-ferrite of diffusional, displacement origin in the grain boundary and acicular forms; and (2) martensite of isothermal and athermal nature, acicular, lamellar, massive, and dendritic. The diversity of the shapes of structural constituents is associated with the effect on their formation of elastic distortions and various mechanisms of deformation relaxation processes.

Shock-induced transformations in crystalline RDX: a uniaxial constant-stress Hugoniostat molecular dynamics simulation study.

PubMed

Bedrov, Dmitry; Hooper, Justin B; Smith, Grant D; Sewell, Thomas D

2009-07-21

Molecular dynamics (MD) simulations of uniaxial shock compression along the [100] and [001] directions in the alpha polymorph of hexahydro-1,3,5-trinitro-1,3,5-triazine (alpha-RDX) have been conducted over a wide range of shock pressures using the uniaxial constant stress Hugoniostat method [Ravelo et al., Phys. Rev. B 70, 014103 (2004)]. We demonstrate that the Hugoniostat method is suitable for studying shock compression in atomic-scale models of energetic materials without the necessity to consider the extremely large simulation cells required for an explicit shock wave simulation. Specifically, direct comparison of results obtained using the Hugoniostat approach to those reported by Thompson and co-workers [Phys. Rev. B 78, 014107 (2008)] based on large-scale MD simulations of shocks using the shock front absorbing boundary condition (SFABC) approach indicates that Hugoniostat simulations of systems containing several thousand molecules reproduced the salient features observed in the SFABC simulations involving roughly a quarter-million molecules, namely, nucleation and growth of nanoscale shear bands for shocks propagating along the [100] direction and the polymorphic alpha-gamma phase transition for shocks directed along the [001] direction. The Hugoniostat simulations yielded predictions of the Hugoniot elastic limit for the [100] shock direction consistent with SFABC simulation results.

Functional reconstitution of prostaglandin E receptor from bovine adrenal medulla with guanine nucleotide binding proteins

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

Negishi, M.; Ito, S.; Yokohama, H.

1988-05-15

Prostaglandin E/sub 2/ (PEG/sub 2/) was found to bind specifically to a 100,000 x g pellet prepared from bovine adrenal medulla. The PGE receptor was associated with a GTP-binding protein (G-protein) and could be covalently cross-linked with this G-protein by dithiobis(succinimidyl propionate) in the 100,000 x g pellet. In order to characterize the G-protein associated with the PGE receptor and reconstitute these proteins in phospholipid vesicles, the authors purified the G-protein to apparent homogeneity from the 100,000 x g pellet. The G-protein served as a substrate of pertussis toxin but differed in its ..cap alpha.. subunit from two known pertussismore » toxin substrate G-proteins (G/sub i/ and G/sub 0/) purified from bovine brain. The molecular weight of the ..cap alpha.. subunit was 40,000, which is between those of G/sub i/ and G/sub 0/. The purified protein was also distinguished immunologically from G/sub i/ and G/sub 0/ and was referred to as G/sub am/. Reconstitution of the PGE receptor with pure C/sub am/, G/sub i/, or G/sub 0/ in phospholipid vesicles resulted in a remarkable restoration of (/sup 3/H)PGE/sub 2/ binding activity in a GTP-dependent manner. The efficiency of these three G-proteins in this capacity was roughly equal. When pertussis toxin- or N-ethylmaleimide-treated G-proteins, instead of the native ones, were reconstituted into vesicles, the restoration of binding activity was no longer observed. These results indicate that the PGE receptor can couple functionally with G/sub am/, G/sub i/, or G/sub 0/ in phospholipid vesicles and suggest that G/sub am/ may be involved in signal transduction of the PGE receptor in bovine adrenal medulla.« less

Structural features of lipoarabinomannan from Mycobacterium bovis BCG. Determination of molecular mass by laser desorption mass spectrometry.

PubMed

Venisse, A; Berjeaud, J M; Chaurand, P; Gilleron, M; Puzo, G

1993-06-15

It was recently shown that mycobacterial lipoarabinomannan (LAM) can be classified into two types (Chatterjee, D., Lowell, K., Rivoire B., McNeil M. R., and Brennan, P. J. (1992) J. Biol. Chem. 267, 6234-6239) according to the presence or absence of mannosyl residues (Manp) located at the nonreducing end of the oligoarabinosyl side chains. These two types of LAM were found in a pathogenic Mycobacterium tuberculosis strain and in an avirulent M. tuberculosis strain, respectively, suggesting that LAM with Manp characterizes virulent and "disease-inducing strains." We now report the structure of the LAM from Mycobacterium bovis Bacille Calmette-Guérin (BCG) strain Pasteur, largely used throughout the world as vaccine against tuberculosis. Using an up-to-date analytical approach, we found that the LAM of M. bovis BCG belongs to the class of LAMs capped with Manp. By means of two-dimensional homonuclear and heteronuclear scalar coupling NMR analysis and methylation data, the sugar spin system assignments were partially established, revealing that the LAM contained two types of terminal Manp and 2-O-linked Manp. From the following four-step process: (i) partial hydrolysis of deacylated LAM (dLAM), (ii) oligosaccharide derivatization with aminobenzoic ethyl ester, (iii) HPLC purification, (iv) FAB/MS-MS analysis; it was shown that the dimannosyl unit alpha-D-Manp-(1-->2)-alpha-D-Manp is the major residue capping the termini of the arabinan of the LAM. In this report, LAM molecular mass determination was established using matrix-assisted UV-laser desorption/ionization mass spectrometry which reveals that the LAM molecular mass is around 17.4 kDa. The similarity of the LAM structures between M. bovis BCG and M. tuberculosis H37Rv is discussed in regard to their function in the immunopathology of mycobacterial infection.

Studies on transposable elements in yeast. I. ROAM mutations causing increased expression of yeast genes: their activation by signals directed toward conjugation functions and their formation by insertion of Tyl repetitive elements

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

Errede, B.; Cardillo, T.S.; Wever, G.

1981-01-01

Mechanisms available to eukaryotic organisms for the coordinate regulation of gene expression are being examined by genetic and biochemical characterization of an unusual mutation, CYC7-H2, which causes over-production of iso-2-cytochrome c in the yeast Saccharomyces cerevisiae. The CYC7-H2 mutation causes overproduction in haploid strains but only a 1- to 40-fold overproduction in MATa/MAT..cap alpha.. diploid strains. This regulation of overproduction has been characterized as a response to signals controlling conjugation in yeast. Furthermore, the abnormal controlling region has been identified as an insertion of a transposable and reiterated Ty1 element adjacent to the structural gene. Therefore, we suggest that Ty1more » elements or portions of Ty1 elements occur adjacent to some of the genes required for conjugation and that they normally function to control expression of this process. The suggested role of reiterated sequences may represent a general mechanism of coordinate regulation in eukaryotes. The CYC7-H2 mutation is closely related to other regulatory mutations occurring at the cargA, cargB and DUR1,2 loci. Similar to the CYC7-H2 mutation, the mutations designated cargA/sup +/O/sup h/, cargB/sup +/O/sup h/, and durO/sup h/ cause constitutive production of their respective gene products at much lower levels of MATa/MAT..cap alpha.. diploid strains than in the corresponding haploid strains. A consistent relationship between conjugation competence and the level of overproduction in all four mutants has been established. Observations characterizing the regulation of overproduction in the CYC7-H2 mutant are presented with the additional and parallel observations for the O/sup h/ mutants. Together these results provide a demonstration of the specificity and equivalence of regulatory control exhibited by ROAM mutants.« less

Formation of glutamine from (/sup 13/N)ammonia, (/sup 13/N)dinitrogen, and (/sup 14/C)glutamate by heterocysts isolated from Anabaena cylindrica

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

Thomas, J.; Meeks, J.C.; Wolk, C.P.

A method is described for the isolation of metabolically active heterocysts from Anabaena cylindrica. These isolated heterocysts accounted for up to 34% of the acetylene-reducing activity of whole filaments and had a specific activity of up to 1,560 nmol of C/sub 2/H/sub 4/ formed per mg of heterocyst chlorophyll per min. Activity of glutamine synthetase was coupled to activity of nitrogenase in isolated heterocysts as shown by acetylene-inhibitable formation of (/sup 13/N)NH/sub 3/ and of amide-labeled (/sup 13/N)glutamine from (/sup 13/N)N/sub 2/. A method is also described for the production of 6-mCi amounts of (/sup 13/N)NH/sub 3/. Isolated heterocysts formedmore » (/sup 13/N)glutamine from (/sup 13/N)NH/sub 3/ and glutamate, and (/sup 14/C)glutamine from NH/sub 3/ and (/sup 14/C)glutamate, in the presence of magnesium adenosine 5'-triphosphate. Methionine sulfoximine strongly inhibited these syntheses. Glutamate synthase is, after nitrogenase and glutamine synthetase, the third sequential enzyme involved in the assimilation of N/sub 2/ by intact filaments. However, the kinetics of solubilization of the activity of glutamate synthase during cavitation of suspensions of A. cylindrica indicated that very little, if any, of the activity of that enzyme was located in heterocysts. Concordantly, isolated heterocysts failed to form substantial amounts of radioactive glutamate from either (/sup 13/N)glutamine or ..cap alpha..-(/sup 14/C)ketoglutarate in the presence of other substrates and cofactors of the glutamate synthase reaction. However, they formed (/sup 14/C)glutamate rapidly from ..cap alpha..-(/sup 14/C)ketoglutarate by aminotransferase reactions, with various amino acids as the nitrogen donor. The implications of these findings with regard to the identities of the substances moving between heterocysts and vegetative cells are discussed.« less

NMR analyses of the conformations of L-isoleucine and L-valine bound to Escherichia coli isoleucyl-tRNA synthetase

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

Kohda, D.; Kawai, G.; Yokoyama, S.

1987-10-06

The 400-MHz /sup 1/H NMR spectra of L-isoleucine and L-valine were measured in the presence of Escherichia coli isoleucyl-tRNA synthetase (IleRS). Because of chemical exchange of L-isoleucine or L-valine between the free state and the IleRS-bound state, a transferred nuclear Overhauser effect (TRNOE) was observed among proton resonances of L-isoleucine or L-valine. However, in the presence of isoleucyl adenylate tightly bound to the amino acid activation site of IleRS, no TRNOE for L-isoleucine or L-valine was observed. This indicates that the observed TRNOE is due to the interaction of L-isoleucine or L-valine with the amino acid activation site of IleRS.more » The conformations of these amino acids in the amino acid activation site of IleRS were determined by the analyses of time dependences of TRNOEs and TRNOE action spectra. The IleRS-bound L-isoleucine takes the gauche/sup +/ form about the C/sub ..cap alpha../-C/sub ..beta../ bond and the trans form about the C/sub ..beta../-C/sub ..gamma../sub 1// bond. The IleRS-bound L-valine takes the guache/sup -/ form about the C/sub ..cap alpha../-C/sub ..beta../ bond. Thus, the conformation of the IleRS-bound L-valine is the same as that of IleRS-bound L-isoleucine except for the delta-methyl group. The side chain of L-isoleucine or L-valine lies in an aliphatic hydrophobic pocket of the active site of IleRS. Such hydrophobic interaction with IleRS is more significant for L-isoleucine than for L-valine. The TRNOE analysis is useful for studying the amino acid discrimination mechanism of aminoacyl-tRNA synthetases.« less

Kinetics and mechanisms of 1,5-dihydroflavin reduction of carbonyl compounds and flavin oxidation of alcohols. III. Oxidation of benzoin by flavin and reduction of benzil by 1,5-dihydroflavin

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

Bruice, T.C.; Taulane, J.P.

1976-11-24

The oxidation of benzoin by lumiflavin-3-acetic acid (Fl/sub ox/) to provide benzil and 1,5-dihydrolumiflavin-3-acetic acid (FlH/sub 2/) is a readily reversible reaction. It has been established that the mechanism involves general base ionization of benzoin carbon acid (..cap alpha..-ketol) to yield endiolate anion, followed by partitioning of the endiolate anion back to benzoin through general acid proton donation and to benzil by reaction with Fl/sub ox/. The reaction of endiolate anion with Fl/sub ox/ is not subject to acid or base catalysis. Evidence that ionization of benzoin precedes its oxidation by Fl/sub ox/ stems from the observation that the ratemore » attributed to the latter process possesses a constant equal to that for racemization of (+)-benzoin and O/sub 2/ oxidation of benzoin and that this rate constant is characterized by a primary deuterium kinetic isotope effect (k/sup benzoin//k/sup ..cap alpha..-/sup 2/H-benzoin/) of 7.24 +- 1.5. Reduction of benzil to benzoin by FlH/sub 2/ is pH and buffer insensitive below the pK/sub a/ of FlH/sub 2/. These results are consistent with either general acid catalyzed attack of benzoin carbanion at the 4a-position of Fl/sub ox/, followed by a specific base catalyzed collapse of adduct to diketone and dihydroflavin (Scheme III), or to the uncatalyzed reaction of carbanion (endiolate anion) with flavin to provide a semidione-flavin radical pair which then goes on to diketone and dihydroflavin in a non-acid-base catalyzed reaction (Scheme V). These mechanisms are discussed in terms of the kinetics of reaction of other carbanion species with flavin.« less

Direct radioimmunoassay of urinary estrogen and pregnanediol glucuronides during the menstrual cycle

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

Stanczyk, F.Z.; Miyakawa, I.; Goebelsmann, U.

Assays measuring immunoreactive estrone glucuronide (E/sub 1/G), estradiol-3-glucuronide (E/sub 2/-3G), estradiol-17..beta..-glucuronide (E/sub 2/-17G), estriol-3-glucuronide (E/sub 3/-3G), estriol-16..cap alpha..-glucuronide (E/sub 3/-16G), and pregnanediol-3..cap alpha..-glucuronide (Pd-3G) directly in diluted urine were developed and validated. These estrogen and pregnanediol glucuronide fractions were measured in aliquots of 24-hour and overnight samples of urine collected daily from seven women for one menstrual cycle. Urinary hormone excretion was correlated with daily serum estradiol (E/sub 2/), progesterone (P), and lutenizing hormonee (LH) levels. A sharp midcycle LH peak preceded by a preovulatory rise in serum E/sub 2/ and followed by luteal phase serum P levels were notedmore » in each of the seven apparently ovulatory cycles. Twenty-four-hour and overnight urinary excretion patterns of estrogen glucuronides were similar to those of serum E/sub 2/. Of the five estrogen glucuronide fractions tested, excretion of E/sub 2/-17G exhibited the earliest and steepest ascending slope of the preovulatory estrogen surge and correlated best with serum E/sub 2/ levels. Urinary excretion of E/sub 1/-G, E/sub 2/-3G, and E/sub 3/-16G also showed an early and steep preovulatory rise and preceded that of E/sub 3/-3G, whereas urinary excretion of E/sub 3/-3G exhibited the poorest correlation with serum E/sub 2/ concentrations. The urinary excretion of Pd-3G rose parallel to serum P levels and was markedly elevated 2 to 3 days after the midcycle LH peak in both 24-hour and overnight collections of urine. These results indicate that among the urinary estrogen conjugate fractions tested, E/sub 2/-17G is the one that most suitably predicts ovulation.« less

Finite field equation of Yang--Mills theory

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

Brandt, R.A.; Wing-Chiu, N.; Yeung, W.

1980-03-01

We consider the finite local field equation -)(1+1/..cap alpha.. (1+f/sub 4/))g/sup munu/D'Alembertian-partial/sup ..mu../partial/sup ..nu../)A/sup nua/ =-(1+f/sub 3/) g/sup 2/N(A/sup c/..nu..A/sup a/..mu..A/sub ..nu..//sup c/) +xxx+(1-s)/sup 2/M/sup 2/A/sup a/..mu.., introduced by Lowenstein to rigorously describe SU(2) Yang--Mills theory, which is written in terms of normal products. We also consider the operator product expansion A/sup c/..nu..(x+xi) A/sup a/..mu..(x) A/sup b/lambda(x-xi) approx...sigma..M/sup c/ab..nu mu..lambda/sub c/'a'b'..nu..'..mu..'lambda' (xi) N(A/sup nuprimec/'A/sup muprimea/'A/sup lambdaprimeb/')(x), and using asymptotic freedom, we compute the leading behavior of the Wilson coefficients M/sup ...//sub .../(xi) with the help of a computer, and express the normal products in the field equation in terms ofmore » products of the c-number Wilson coefficients and of operator products like A/sup c/..nu..(x+xi) A/sup a/..mu..(x) A/sup b/lambda(x-xi) at separated points. Our result is -)(1+(1/..cap alpha..)(1+f/sub 4/))g/sup munu/D'Alembertian-partial/sup ..mu../partial/sup ..nu../)A/sup nua/ =-(1+f/sub 3/) g/sup 2/lim/sub xiarrow-right0/) (lnxi)/sup -0.28/2b/(A/sup c/..nu.. (x+xi) A/sup a/..mu..(x) A/sub ..nu..//sup c/(x-xi) +epsilon/sup a/bcA/sup muc/(x+xi) partial/sup ..nu../A/sup b//sub ..nu../(x)+xxx) +xxx)+(1-s)/sup 2/M/sup 2/A/sup a/..mu.., where ..beta.. (g) =-bg/sup 3/, and so (lnxi)/sup -0.28/2b/ is the leading behavior of the c-number coefficient multiplying the operator products in the field equation.« less

Large Plant Growth Chambers: Flying Soon on a Space Station near You!

NASA Technical Reports Server (NTRS)

Massa, Gioia D.; Morrow, Robert C.; Levine, Howard G.

2014-01-01

The International Space Station (ISS) now has platforms for conducting research on horticultural plant species, and those capabilities continue to grow. The Veggie vegetable production system will be deployed to the ISS in Spring of 2014 to act as an applied research platform with goals of studying food production in space, providing the crew with a source of fresh food, allowing behavioral health and plant microbiology experimentation, and being a source of recreation and enjoyment for the crew. Veggie was conceived, designed, and constructed by Orbital Technologies Corporation (ORBITEC, Madison, WI). Veggie is the largest plant growth chamber that NASA has flown to date, and is capable of growing a wide array of horticultural crops. It was designed for low energy usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nanometers), blue, (455 nanometers) and green (530 nanometers) light emitting diodes. Interfacing with the light cap is an extendable bellows baseplate secured to the light cap via magnetic closures and stabilized with extensible flexible arms. The baseplate contains vents allowing air from the ISS cabin to be pulled through the plant growth area by a fan in the light cap. The baseplate holds a Veggie root mat reservoir that will supply water to plant pillows attached via elastic cords. Plant pillows are packages of growth media and seeds that will be sent to ISS dry and installed and hydrated on orbit. Pillows can be constructed in various sizes for different plant types. Watering will be via passive wicking from the root mat to the pillows. Science procedures will include photography or videography, plant thinning, pollination, harvesting, microbial sampling, water sampling, etcetera. Veggie is one of the ISS flight options currently available for research investigations on plants. The Plant Habitat (PH) is being designed and constructed through a NASA-ORBITEC collaboration, and is scheduled to fly on ISS around 2016. This large plant chamber will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional monitoring capabilities include leaf temperature sensing and root zone moisture and oxygen sensing. The PH light cap will have red (630 nanometers), blue (450 nanometers), green (525 nanometers), far red (730 nanometers) and broad spectrum white light emitting diodes. There will be several internal cameras to monitor and record plant growth and operations.

Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx

NASA Astrophysics Data System (ADS)

Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

2011-09-01

Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. The BL had a depth of 1140 ± 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and meso-scale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October-4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cloud LWP relationship reveals that during the typical well-mixed BL days the cloud LWP increased with the CCN concentrations. On the other hand, meteorological factors and the decoupling processes have large influences on the cloud LWP variation as well.

The Radioactive Ion Beams in Brazil (RIBRAS) facility. Description, program, main results, future plans

NASA Astrophysics Data System (ADS)

Lépine-Szily, A.; Lichtenthäler, R.; Guimarães, V.

2014-08-01

RIBRAS (Radioactive Ion Beams in Brazil) is a facility installed at the Institute of Physics of the University of São Paulo (IFUSP), Brazil. The RIBRAS system consists of two superconducting solenoids and uses the "in-flight method" to produce radioactive ion beams using the primary beam provided by the 8UD Pelletron Tandem of IFUSP. The ion beams produced so far by RIBRAS are 6He, 8Li, 7Be, 10Be, 8B, 12B with intensities that can vary from 104 to 106 pps. Initially the experimental program covered the study of elastic and inelastic scattering with the objective to study the interaction potential and the reaction mechanisms between weakly bound (RIB) and halo (6He and 8B projectiles on light, medium and heavy mass targets. With highly purified beams, the study of resonant elastic scattering and resonant transfer reactions, using inverse kinematics and thick targets, has also been included in our experimental program. Also, transfer reactions of astrophysical interest and fusion reactions induced by halo nuclei are part of the near-future research program. Our recent results on elastic scattering, alpha-particle production and total reaction cross sections, as well as the resonant elastic and transfer reactions, are presented. Our plans for the near future are related to the installation of a new beam line and a cave for gamma-ray detection. We intend to place in operation a large area neutron detector available in our laboratory. The long-range plans could be the move of the RIBRAS system to the more energetic beam line of the LINAC post-accelerator (10MeV/nucleon primary beams) still in construction in our laboratory.

The initial stage of uranium oxidation: mechanism of UO(2) scale formation in the presence of a native lateral stress field.

PubMed

Chernia, Z; Ben-Eliyahu, Y; Kimmel, G; Braun, G; Sariel, J

2006-11-23

In this work, an oxidation model for alpha-uranium is presented. It describes the internally lateral stress field built in the oxide scale during the reaction. The thickness of the elastic, stress-preserving oxide (UO(2+x)) scale is less than 0.5 microm. A lateral, 6.5 GPa stress field has been calculated from strains derived from line shifts (delta(2theta)) as measured by the X-ray diffraction of UO(2). It is shown that in the elastic growth domain, (110) is the main UO(2) growth plane for gas-solid oxidation. The diffusion-limited oxidation mechanism discussed here is based on the known "2:2:2" cluster theory which describes the mechanism of fluorite-based hyperstoichiometric oxides. In this study, it is adapted to describe oxygen-anion hopping. Anion hopping toward the oxide-metal interface proceeds at high rates in the [110] direction, hence making this pipeline route the principal growth direction in UO(2) formation. It is further argued that growth in the pure elastic domain of the oxide scale should be attributed entirely to anion hopping in 110. Anions, diffusing isotropically via grain boundaries and cracks, are shown to have a significant impact on the overall oxidation rate in relatively thick (>0.35 microm) oxide scales if followed by an avalanche break off in the postelastic regime. Stress affects oxidation in the elastic domain by controlling the hopping rate directly. In the postelastic regime, stress weakens hopping, indirectly, by enhancing isotropic diffusion. Surface roughness presents an additional hindering factor for the anion hopping. In comparison to anisotropic hopping, diffusion of isotropic hopping has a lower activation energy barrier. Therefore, a relatively stronger impact at lower temperatures due to isotropic diffusion is displayed.

[Factorial Structure of the Cardiff Anomalous Perceptions Scale (CAPS) in a Colombian Population Sample].

PubMed

Tamayo-Agudelo, William; Jaén-Moreno, María José; Luque-Luque, Rogelio

2015-01-01

The continuum hypothesis of psychosis assumes that hallucinations are not exclusive of psychotic disorders. A number of psychometric tests have been developed to assess psychosis using a dimensional model. To determine the factorial structure of the Cardiff Anomalous Perceptions Scale (CAPS) for the Colombian population, and to contrast the fit of two factor models previously reported in the literature by conducting a confirmatory factor analysis (CFA). This was a cross-sectional study in which 207 subjects from the general population were assessed using the Cardiff Anomalous Perceptions Scale. A two-factor structure with acceptable ordinal alpha coefficients (α=.88 and α=.87) was found. One factor gathered items related to multimodal perceptual alterations, and a second factor grouped items related with experiences linked to the temporal lobe. The analysis of the first factor indicated that it was dependent on cultural issues for the interpretation of sensations. The second factor appeared almost unchanged on diverse populations, suggesting its transcultural character. When comparing the models proposed by Bell et al. and Jaen-Moreno et al. using the data obtained from the sample, the confirmatory factor analysis conducted indicated inadequate goodness-of-fit indexes (χ(2)). However, some incremental goodness-of-fit indexes (normalized χ(2) [RMSEA]) were acceptable. The Jaén-Moreno et al. model showed the best fit to the data collected from the Colombian sample. The factorial structure of CAPS for the Colombian population appears to be sensitive to cultural issues, especially when describing anomalous sensorial experiences. Copyright © 2015 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Protective effects of aerobic exercise on acute lung injury induced by LPS in mice

PubMed Central

2012-01-01

Introduction The regular practice of physical exercise has been associated with beneficial effects on various pulmonary conditions. We investigated the mechanisms involved in the protective effect of exercise in a model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Methods Mice were divided into four groups: Control (CTR), Exercise (Exe), LPS, and Exercise + LPS (Exe + LPS). Exercised mice were trained using low intensity daily exercise for five weeks. LPS and Exe + LPS mice received 200 µg of LPS intratracheally 48 hours after the last physical test. We measured exhaled nitric oxide (eNO); respiratory mechanics; neutrophil density in lung tissue; protein leakage; bronchoalveolar lavage fluid (BALF) cell counts; cytokine levels in BALF, plasma and lung tissue; antioxidant activity in lung tissue; and tissue expression of glucocorticoid receptors (Gre). Results LPS instillation resulted in increased eNO, neutrophils in BALF and tissue, pulmonary resistance and elastance, protein leakage, TNF-alpha in lung tissue, plasma levels of IL-6 and IL-10, and IL-1beta, IL-6 and KC levels in BALF compared to CTR (P ≤0.02). Aerobic exercise resulted in decreases in eNO levels, neutrophil density and TNF-alpha expression in lung tissue, pulmonary resistance and elastance, and increased the levels of IL-6, IL-10, superoxide dismutase (SOD-2) and Gre in lung tissue and IL-1beta in BALF compared to the LPS group (P ≤0.04). Conclusions Aerobic exercise plays important roles in protecting the lungs from the inflammatory effects of LPS-induced ALI. The effects of exercise are mainly mediated by the expression of anti-inflammatory cytokines and antioxidants, suggesting that exercise can modulate the inflammatory-anti-inflammatory and the oxidative-antioxidative balance in the early phase of ALI. PMID:23078757

The phase behavior of cationic lipid-DNA complexes.

PubMed Central

May, S; Harries, D; Ben-Shaul, A

2000-01-01

We present a theoretical analysis of the phase behavior of solutions containing DNA, cationic lipids, and nonionic (helper) lipids. Our model allows for five possible structures, treated as incompressible macroscopic phases: two lipid-DNA composite (lipoplex) phases, namely, the lamellar (L(alpha)(C)) and hexagonal (H(II)(C)) complexes; two binary (cationic/neutral) lipid phases, that is, the bilayer (L(alpha)) and inverse-hexagonal (H(II)) structures, and uncomplexed DNA. The free energy of the four lipid-containing phases is expressed as a sum of composition-dependent electrostatic, elastic, and mixing terms. The electrostatic free energies of all phases are calculated based on Poisson-Boltzmann theory. The phase diagram of the system is evaluated by minimizing the total free energy of the three-component mixture with respect to all the compositional degrees of freedom. We show that the phase behavior, in particular the preferred lipid-DNA complex geometry, is governed by a subtle interplay between the electrostatic, elastic, and mixing terms, which depend, in turn, on the lipid composition and lipid/DNA ratio. Detailed calculations are presented for three prototypical systems, exhibiting markedly different phase behaviors. The simplest mixture corresponds to a rigid planar membrane as the lipid source, in which case, only lamellar complexes appear in solution. When the membranes are "soft" (i.e., low bending modulus) the system exhibits the formation of both lamellar and hexagonal complexes, sometimes coexisting with each other, and with pure lipid or DNA phases. The last system corresponds to a lipid mixture involving helper lipids with strong propensity toward the inverse-hexagonal phase. Here, again, the phase diagram is rather complex, revealing a multitude of phase transitions and coexistences. Lamellar and hexagonal complexes appear, sometimes together, in different regions of the phase diagram. PMID:10733951

The effects of α-lipoic acid on aortic injury and hypertension in the rat remnant kidney (5/6 nephrectomy) model.

PubMed

Ergür, Bekir Uğur; Çilaker Mıcılı, Serap; Yılmaz, Osman; Akokay, Pınar

2015-06-01

The present study was designed to investigate the effects of α-lipoic acid on the abdominal aorta and hypertension in a remnant kidney model histomorphometrically, immunohistochemically, and ultrastructurally. We surgically reduced the renal tissue mass to 5/6 by applying a remnant kidney model. The rats were divided into 4 groups: Group 1- control group, Group 2- lipoic acid group, Group 3- 5/6 nephrectomy group, and Group IV: 5/6 nephrectomy+lipoic acid-treated group. Lipoic acid solution 100 mg/kg was administered by oral gavage for 8 weeks to Groups II and IV. At the end of the experiment, systemic mean blood pressure was monitored. Then, aortic tissues were removed and fixed. After routine histological procedures, tissue sections were examined histochemically, immunohistochemically (type I angiotensin receptor, vascular endothelial growth factor, alpha-smooth muscle actin), and ultrastructurally. The blood pressure measurements in 5/6 nephrectomy group were significantly higher compared to other groups. In the 5/6 nephrectomy+lipoic acid group, measured blood pressure values and tunica media thickness were significantly lower than in the 5/6 nephrectomy group. In the 5/6 nephrectomy+lipoic acid group, decreased aortic wall thickness, regularity in the structure of elastic fibrils, and more organized elastic lamellae were seen. The expression of type I angiotensin receptor, vascular endothelial growth factor, alpha-smooth muscle actin in the 5/6 nephrectomy+lipoic acid group was decreased compared to the 5/6 nephrectomy group. In the present study, we found that α-lipoic acid could be a favorable agent for the target organ effects of secondary hypertension.

Nondestructive Measurement of the Evolution of Layer-Specific Mechanical Properties in Sub-10 nm Bilayer Films.

PubMed

Hoogeboom-Pot, Kathleen M; Turgut, Emrah; Hernandez-Charpak, Jorge N; Shaw, Justin M; Kapteyn, Henry C; Murnane, Margaret M; Nardi, Damiano

2016-08-10

We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for the first time, with single-monolayer sensitivity. We show that in Ni/Ta nanostructured systems, while their density ratio is not meaningfully changed from that expected in bulk, their elastic properties are significantly modified, where nickel softens while tantalum stiffens, relative to their bulk counterparts. In particular, the presence or absence of the Ta capping layer influences the mechanical properties of the Ni film. This nondestructive nanomechanical measurement technique represents the first approach to date able to distinguish the properties of composite materials well below 100 nm in thickness. This capability is critical for understanding and optimizing the strength, flexibility and reliability of materials in a host of nanostructured electronic, photovoltaic, and thermoelectric devices.

A process for the chemical preparation of high-field ZnO varistors

DOEpatents

Brooks, R.A.; Dosch, R.G.; Tuttle, B.A.

1986-02-19

Chemical preparation techniques involving co-precipitation of metals are used to provide microstructural characteristics necessary in order to produce ZnO varistors and their precursors for high field applications. The varistors produced have homogeneous and/or uniform dopant distributions and a submicron average grain size with a narrow size distribution. Precursor powders are prepared via chemical precipitation techniques and varistors made by sintering uniaxially and/or isostatically pressed pellets. Using these methods, varistors were made which were suitable for high-power applications, having values of breakdown field, E/sub B/, in the 10 to 100 kV/cm range, ..cap alpha.. > 30 and densities in the range of 65 to 99% of theoretical, depending on both composition and sintering temperature.

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

Wemmer, D.E.; Kumar, N.V.; Metrione, R.M.

Toxin II from Radianthus paumotensis (Rp/sub II/) has been investigated by high-resolution NMR and chemical sequencing methods. Resonance assignments have been obtained for this protein by the sequential approach. NMR assignments could not be made consistent with the previously reported primary sequence for this protein, and chemical methods have been used to determine a sequence with which the NMR data are consistent. Analysis of the 2D NOE spectra shows that the protein secondary structure is comprised of two sequences of ..beta..-sheet, probably joined into a distorted continuous sheet, connected by turns and extended loops, without any regular ..cap alpha..-helical segments.more » The residues previously implicated in activity in this class of proteins, D8 and R13, occur in a loop region.« less

Electrical resistivity of La

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

Legvold, S.; Burgardt, P.; Beaudry, B.J.

1977-09-15

The electrical resistivity of high-purity double hexagonal-close-packed (dhcp) ..cap alpha..-La from 5 to 300 K is reported. Measurements were made on small-grained samples prepared by heat treatment of cold-worked lanthanum. Measurements were also made on samples cut in different directions from an ingot slowly cooled from the molten state. The room-temperature results were all within 2% of the mean value. Chemically pure ..beta..-La (fcc) cannot be retained at room temperature, hence, measurements were made on an fcc sample of La containing 0.2-at. % Gd and approx. 0.8-at. % total interstitial nonmetallic impurities. The cubic form has almost the same typemore » of temperature dependence as the dhcp form, but has a 10% lower magnitude.« less

Collective effects on activated segmental relaxation in supercooled polymer melts

NASA Astrophysics Data System (ADS)

Mirigian, Stephen; Schweizer, Kenneth

2013-03-01

We extend the polymer nonlinear Langevin equation (NLE) theory of activated segmental dynamics in supercooled polymer melts in two new directions. First, a well-defined mapping from real monomers to a freely-jointed chain is formulated that retains information about chain stiffness, monomer volume, and the amplitude of thermal density fluctuations. Second, collective effects beyond the local cage scale are included based on an elastic solid-state perspective in the ``shoving model'' spirit which accounts for longer range contributions to the activation barrier. In contrast to previous phenomenological treatments of this model, we formulate an explicit microscopic picture of the hopping event, and derive, not assume, that the collective barrier is directly related to the elastic shear modulus. Local hopping is thus renormalized by collective motions of the surroundings that are required to physically accommodate it. Using the PRISM theory of structure, and known compressibility and chain statistics information, quantitative applications of the new theory to predict the temperature and chain length dependence of the alpha time, shear modulus, and fragility are carried out for a range of real polymer liquids and compared to experiment.

Inclusive inelastic scattering of heavy ions and nuclear correlations

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.; Khandelwal, Govind S.

1990-01-01

Calculations of inclusive inelastic scattering distributions for heavy ion collisions are considered within the high energy optical model. Using ground state sum rules, the inclusive projectile and complete projectile-target inelastic angular distributions are treated in both independent particle and correlated nuclear models. Comparisons between the models introduced are made for alpha particles colliding with He-4, C-12, and O-16 targets and protons colliding with O-16. Results indicate that correlations contribute significantly, at small momentum transfers, to the inelastic sum. Correlation effects are hidden, however, when total scattering distributions are considered because of the dominance of elastic scattering at small momentum transfers.

Closure Report for Corrective Action Unit 573: Alpha Contaminated Sites Nevada National Security Site, Nevada

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

Matthews, Patrick

This Closure Report (CR) presents information supporting the closure of Corrective Action Unit (CAU) 573: Alpha Contaminated Sites, Nevada National Security Site, Nevada. CAU 573 comprises the two corrective action sites (CASs): 05-23-02-GMX Alpha Contaminated Are-Closure in Place and 05-45-01-Atmospheric Test Site - Hamilton- Clean Closure. The purpose of this CR is to provide justification and documentation supporting the recommendation that no further corrective action is needed for CAU 573 based on the implementation of the corrective actions. Corrective action activities were performed at Hamilton from May 25 through June 30, 2016; and at GMX from May 25 to Octobermore » 27, 2016, as set forth in the Corrective Action Decision Document (CADD)/Corrective Action Plan (CAP) for Corrective Action Unit 573: Alpha Contaminated Sites; and in accordance with the Soils Activity Quality Assurance Plan, which establishes requirements, technical planning, and general quality practices. Verification sample results were evaluated against data quality objective criteria developed by stakeholders that included representatives from the Nevada Division of Environmental Protection and the DOE, National Nuclear Security Administration Nevada Field Office (NNSA/NFO) during the corrective action alternative (CAA) meeting held on November 24, 2015. Radiological doses exceeding the final action level were assumed to be present within the high contamination areas associated with CAS 05-23-02, thus requiring corrective action. It was also assumed that radionuclides were present at levels that require corrective action within the soil/debris pile associated with CAS 05-45-01. During the CAU 573 CAA meeting, the CAA of closure in place with a use restriction (UR) was selected by the stakeholders as the preferred corrective action of the high contamination areas at CAS 05-23-02 (GMX), which contain high levels of removable contamination; and the CAA of clean closure was selected by the stakeholders as preferred corrective action for the debris pile at CAS 05-45-01 (Hamilton). The closure in place was accomplished by posting signs containing a warning label on the existing contamination area fence line; and recording the FFACO UR and administrative UR in the FFACO database, the NNSA/NFO CAU/CAS files, and the management and operating contractor Geographic Information Systems. The clean closure was accomplished by excavating the soil/debris pile, disposing of the contents at the Area 5 Radioactive Waste Management Complex, and collecting verification samples. The corrective actions were implemented as stipulated in the CADD/CAP, and verification sample results confirm that the criteria for the completion of corrective actions have been met. Based on the implementation of these corrective actions, NNSA/NFO provides the following recommendations: No further corrective actions are necessary for CAU 573; The Nevada Division of Environmental Protection should issue a Notice of Completion to NNSA/NFO for closure of CAU 573; CAU 573 should be moved from Appendix III to Appendix IV of the FFACO.« less

Volatility and Uncertainty in Environmental Policy

NASA Astrophysics Data System (ADS)

Maniloff, Peter Taylor

Environmental policy is increasingly implemented via market mechanisms. While this is in many ways a great success for the economics profession, a number of questions remain. In this dissertation, I empirically explore the question of what will happen as environmental outcomes are coupled to potentially volatile market phenomena, whether policies can insulate environmental outcomes and market shocks, and policymakers should act to mitigate such volatility. I use a variety of empirical methods including reduced form and structural econometrics as well as theoretical models to consider a variety of policy, market, and institutional contexts. The effectiveness of market interventions depends on the context and on the policy mechanism. In particular, energy markets are characterized by low demand elasticities and kinked supply curves which are very flat below a capacity constraint (elastic) and very steep above it (inelastic). This means that a quantity-based policy that acts on demand, such as releasing additional pollution emission allowances from a reserved fund would be an effective way to constrain price shocks in a cap-and-trade system. However, a quantity-based policy that lowers the need for inframarginal supply, such as using ethanol as an oil product substitute to mitigate oil shocks, would be ineffective. Similarly, the benefits of such interventions depends on the macroeconomic impacts of price shocks from the sector. Relatedly, I show that a liability rule designed to reduce risk from low-probability, high-consequence oil spills have very low compliance costs.

Mesoscopic model of actin-based propulsion.

PubMed

Zhu, Jie; Mogilner, Alex

2012-01-01

Two theoretical models dominate current understanding of actin-based propulsion: microscopic polymerization ratchet model predicts that growing and writhing actin filaments generate forces and movements, while macroscopic elastic propulsion model suggests that deformation and stress of growing actin gel are responsible for the propulsion. We examine both experimentally and computationally the 2D movement of ellipsoidal beads propelled by actin tails and show that neither of the two models can explain the observed bistability of the orientation of the beads. To explain the data, we develop a 2D hybrid mesoscopic model by reconciling these two models such that individual actin filaments undergoing nucleation, elongation, attachment, detachment and capping are embedded into the boundary of a node-spring viscoelastic network representing the macroscopic actin gel. Stochastic simulations of this 'in silico' actin network show that the combined effects of the macroscopic elastic deformation and microscopic ratchets can explain the observed bistable orientation of the actin-propelled ellipsoidal beads. To test the theory further, we analyze observed distribution of the curvatures of the trajectories and show that the hybrid model's predictions fit the data. Finally, we demonstrate that the model can explain both concave-up and concave-down force-velocity relations for growing actin networks depending on the characteristic time scale and network recoil. To summarize, we propose that both microscopic polymerization ratchets and macroscopic stresses of the deformable actin network are responsible for the force and movement generation.

Using Amazon's Elastic Compute Cloud to dynamically scale CMS computational resources

NASA Astrophysics Data System (ADS)

Evans, D.; Fisk, I.; Holzman, B.; Melo, A.; Metson, S.; Pordes, R.; Sheldon, P.; Tiradani, A.

2011-12-01

Large international scientific collaborations such as the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider have traditionally addressed their data reduction and analysis needs by building and maintaining dedicated computational infrastructure. Emerging cloud computing services such as Amazon's Elastic Compute Cloud (EC2) offer short-term CPU and storage resources with costs based on usage. These services allow experiments to purchase computing resources as needed, without significant prior planning and without long term investments in facilities and their management. We have demonstrated that services such as EC2 can successfully be integrated into the production-computing model of CMS, and find that they work very well as worker nodes. The cost-structure and transient nature of EC2 services makes them inappropriate for some CMS production services and functions. We also found that the resources are not truely "on-demand" as limits and caps on usage are imposed. Our trial workflows allow us to make a cost comparison between EC2 resources and dedicated CMS resources at a University, and conclude that it is most cost effective to purchase dedicated resources for the "base-line" needs of experiments such as CMS. However, if the ability to use cloud computing resources is built into an experiment's software framework before demand requires their use, cloud computing resources make sense for bursting during times when spikes in usage are required.

Achilles detachment in rat and stable gastric pentadecapeptide BPC 157: Promoted tendon-to-bone healing and opposed corticosteroid aggravation.

PubMed

Krivic, Andrija; Anic, Tomislav; Seiwerth, Sven; Huljev, Dubravko; Sikiric, Predrag

2006-05-01

Stable gastric pentadecapeptide BPC 157 (BPC 157, as an antiulcer agent in clinical trials for inflammatory bowel disease; PLD-116, PL 14736, Pliva, no toxicity reported) alone (without carrier) ameliorates healing of tendon and bone, respectively, as well as other tissues. Thereby, we focus on Achilles tendon-to-bone healing: tendon to bone could not be healed spontaneously, but it was recovered by this peptide. After the rat's Achilles tendon was sharply transected from calcaneal bone, agents [BPC 157 (10 microg, 10 ng, 10 pg), 6alpha-methylprednisolone (1 mg), 0.9% NaCl (5 mL)] were given alone or in combination [/kg body weight (b.w.) intraperitoneally, once time daily, first 30-min after surgery, last 24 h before analysis]. Tested at days 1, 4, 7, 10, 14, and 21 after Achilles detachment, BPC 157 improves healing functionally [Achilles functional index (AFI) values substantially increased], biomechanically (load to failure, stiffness, and Young elasticity modulus significantly increased), macro/microscopically, immunohistochemistry (better organization of collagen fibers, and advanced vascular appearance, more collagen type I). 6alpha-Methylprednisolone consistently aggravates the healing, while BPC 157 substantially reduces 6alpha-methylprednisolone healing aggravation. Thus, direct tendon-to-bone healing using stabile nontoxic peptide BPC 157 without a carrier might successfully exchange the present reconstructive surgical methods. Copyright 2006 Orthopaedic Research Society.

Three-dimensional CTOA and constraint effects during stable tearing in a thin-sheet material

NASA Technical Reports Server (NTRS)

Dawicke, D. S.; Newman, J. C., Jr.; Bigelow, C. A.

1995-01-01

A small strain theory, three-dimensional elastic-plastic finite element analysis was used to simulate fracture in thin sheet 2024-T3 aluminum alloy in the T-L orientation. Both straight and tunneled cracks were modeled. The tunneled crack front shapes as a function of applied stress were obtained from the fracture surface of tested specimens. The stable crack growth behavior was measured at the specimen surface as a function of applied stress. The fracture simulation modeled the crack tunneling and extension as a function of applied stress. The results indicated that the global constraint factor, alpha(sub g), initially dropped during stable crack growth. After peak applied stress was achieved, alpha(sub g) began to increase slightly. The effect of crack front shape on alpha(sub g) was small, but the crack front shape did greatly influence the local constraint and through-thickness crack-tip opening angle (CTOA) behavior. The surface values of CTOA for the tunneled crack front model agreed well with experimental measurements, showing the same initial decrease from high values during the initial 3mm of crack growth at the specimen's surface. At the same time, the interior CTOA values increased from low angles. After the initial stable tearing region, the CTOA was constant through the thickness. The three-dimensional analysis appears to confirm the potential of CTOA as a two-dimensional fracture criterion.

Structure, mechanical properties, and grindability of dental Ti-Zr alloys.

PubMed

Ho, Wen-Fu; Chen, Wei-Kai; Wu, Shih-Ching; Hsu, Hsueh-Chuan

2008-10-01

Structure, mechanical properties and grindability of a series of binary Ti-Zr alloys with zirconium contents ranging from 10 to 40 wt% have been investigated. Commercially pure titanium (c.p. Ti) was used as a control. Experimental results indicated that the diffraction peaks of all the Ti-Zr alloys matched those for alpha Ti. No beta-phase peaks were found. The hardness of the Ti-Zr alloys increased as the Zr contents increased, and ranged from 266 HV (Ti-10Zr) to 350 HV (Ti-40Zr). As the concentration of zirconium in the alloys increased, the strength, elastic recovery angles and hardness increased. Moreover, the elastically recoverable angle of Ti-40Zr was higher than of c.p. Ti by as much as 550%. The grindability of each metal was found to be largely dependent on the grinding conditions. The Ti-40Zr alloy had a higher grinding rate and grinding ratio than c.p. Ti at low speed. The grinding rate of the Ti-40Zr alloy at 500 m/min was about 1.8 times larger than that of c.p. Ti, and the grinding ratio was about 1.6 times larger than that of c.p. Ti. Our research suggested that the Ti-40Zr alloy has better mechanical properties, excellent elastic recovery capability and improved grindability at low grinding speed. The Ti-40Zr alloy has a great potential for use as a dental machining alloy.

InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

NASA Astrophysics Data System (ADS)

Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

2014-12-01

Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and Síðujökull (Sí.) outlet glaciers. The black and grey arrows show the azimuth of the satellite and the look direction, respectively. (a) Wrapped interferogram showing the surge deformation (2π = 28.3 mm deformation). (b) Unwrapped interferogram with the black star as the reference area and negative values indicating line of sight lengthening (Auriac et al., 2014, doi:10.1093/gji/ggu205).

Cap-and-Trade Modeling and Analysis: Congested Electricity Market Equilibrium

NASA Astrophysics Data System (ADS)

Limpaitoon, Tanachai

This dissertation presents an equilibrium framework for analyzing the impact of cap-and-trade regulation on transmission-constrained electricity market. The cap-and-trade regulation of greenhouse gas emissions has gained momentum in the past decade. The impact of the regulation and its efficacy in the electric power industry depend on interactions of demand elasticity, transmission network, market structure, and strategic behavior of firms. I develop an equilibrium model of an oligopoly electricity market in conjunction with a market for tradable emissions permits to study the implications of such interactions. My goal is to identify inefficiencies that may arise from policy design elements and to avoid any unintended adverse consequences on the electric power sector. I demonstrate this modeling framework with three case studies examining the impact of carbon cap-and-trade regulation. In the first case study, I study equilibrium results under various scenarios of resource ownership and emission targets using a 24-bus IEEE electric transmission system. The second and third case studies apply the equilibrium model to a realistic electricity market, Western Electricity Coordinating Council (WECC) 225-bus system with a detailed representation of the California market. In the first and second case studies, I examine oligopoly in electricity with perfect competition in the permit market. I find that under a stringent emission cap and a high degree of concentration of non-polluting firms, the electricity market is subject to potential abuses of market power. Also, market power can occur in the procurement of non-polluting energy through the permit market when non-polluting resources are geographically concentrated in a transmission-constrained market. In the third case study, I relax the competitive market structure assumption of the permit market by allowing oligopolistic competition in the market through a conjectural variation approach. A short-term equilibrium analysis of the joint markets in the presence of market power reveals that strategic permit trading can play a vital role in determining economic outcomes in the electricity market. In particular, I find that a firm with more efficient technologies can employ strategic withholding of permits, which allows for its increase in output share in the electricity market at the expense of other less efficient firms. In addition, strategic permit trading can influence patterns of transmission congestion. These results illustrate that market structure and transmission congestion can have a significant impact on the market performance and environmental outcome of the regulation while the interactions of such factors can lead to unintended consequences. The proposed approach is proven useful as a tool for market monitoring purposes in the short run from the perspective of a system operator, whose responsibility has become indirectly intertwined with emission trading regulation.

Modelling mechanical behaviour of limestone under reservoir conditions

NASA Astrophysics Data System (ADS)

Carvalho Coelho, Lúcia; Soares, Antonio Claudio; Ebecken, Nelson Francisco F.; Drummond Alves, José Luis; Landau, Luiz

2006-12-01

High porosity and low permeability limestone has presented pore collapse. As fluid is withdrawn from these reservoirs, the effective stresses acting on the rock increase. If the strength of the rock is overcome, pore collapse may occur, leading to irreversible compaction of porous media with permeability and porosity reduction. It impacts on fluid withdrawal. Most of reservoirs have been discovered in weak formations, which are susceptible to this phenomenon. This work presents a study on the mechanical behaviour of a porous limestone from a reservoir located in Campos Basin, offshore Brazil. An experimental program was undergone in order to define its elastic plastic behaviour. The tests reproduced the loading path conditions expected in a reservoir under production. Parameters of the cap model were fitted to these tests and numerical simulations were run. The numerical simulations presented a good agreement with the experimental tests. Copyright

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

Mohapatra, Pratyasha; Shaw, Santosh; Mendivelso-Perez, Deyny

Removing organics from hybrid nanostructures is a crucial step in many bottom-up materials fabrication approaches. It is usually assumed that calcination is an effective solution to this problem, especially for thin films. This assumption has led to its application in thousands of papers. Here in this paper, we show that this general assumption is incorrect by using a relevant and highly controlled model system consisting of thin films of ligand-capped ZrO 2 nanocrystals. After calcination at 800 °C for 12 h, while Raman spectroscopy fails to detect the ligands after calcination, elastic backscattering spectrometry characterization demonstrates that ~18% of themore » original carbon atoms are still present in the film. By comparison plasma processing successfully removes the ligands. Our growth kinetic analysis shows that the calcined materials have significantly different interfacial properties than the plasma-processed counterparts. Calcination is not a reliable strategy for the production of single-phase all-inorganic materials from colloidal nanoparticles.« less

Yeast Droplets

NASA Astrophysics Data System (ADS)

Nguyen, Baochi; Upadhyaya, Arpita; van Oudenaarden, Alexander; Brenner, Michael

2002-11-01

It is well known that the Young's law and surface tension govern the shape of liquid droplets on solid surfaces. Here we address through experiments and theory the shape of growing aggregates of yeast on agar substrates, and assess whether these ideas still hold. Experiments are carried out on Baker's yeast, with different levels of expressions of an adhesive protein governing cell-cell and cell-substrate adhesion. Changing either the agar concentration or the expression of this protein modifies the local contact angle of a yeast droplet. When the colony is small, the shape is a spherical cap with the contact angle obeying Young's law. However, above a critical volume this structure is unstable, and the droplet becomes nonspherical. We present a theoretical model where this instability is caused by bulk elastic effects. The model predicts that the transition depends on both volume and contact angle, in a manner quantitatively consistent with our experiments.

Spatial and directional control of self-assembled wrinkle patterns by UV light absorption

NASA Astrophysics Data System (ADS)

Kortz, C.; Oesterschulze, E.

2017-12-01

Wrinkle formation on surfaces is a phenomenon that is observed in layered systems with a compressed elastic thin capping layer residing on a viscoelastic film. So far, the properties of the viscoelastic material could only be changed replacing it by another material. Here, we propose to use a photosensitive material whose viscoelastic properties, Young's modulus, and glass transition temperature can easily be adjusted by the absorption of UV light. Employing UV lithography masks during the exposure, we gain additionally spatial and directional control of the self-assembled wrinkle pattern formation that relies on a spinodal decomposition process. Inspired by the results on surface wrinkling and its dependence on the intrinsic stress, we also derive a method to avoid wrinkling locally by tailoring the mechanical stress distribution in the layered system choosing UV masks with convex patterns. This is of particular interest in technical applications where the buckling of surfaces is undesirable.

Mechanical properties of experimental composites with different calcium phosphates fillers.

PubMed

Okulus, Zuzanna; Voelkel, Adam

2017-09-01

Calcium phosphates (CaPs)-containing composites have already shown good properties from the point of view of dental restorative materials. The purpose of this study was to examine the crucial mechanical properties of twelve hydroxyapatite- or tricalcium phosphate-filled composites. The raw and surface-treated forms of both CaP fillers were applied. As a reference materials two experimental glass-containing composites and one commercial dental restorative composite were applied. Nano-hardness, elastic modulus, compressive, flexural and diametral tensile strength of all studied materials were determined. Application of statistical methods (one-way analysis of variance and cluster agglomerative analysis) allowed for assessing the similarities between examined materials according to the values of studied parameters. The obtained results show that in almost all cases the mechanical properties of experimental CaPs-composites are comparable or even better than mechanical properties of examined reference materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth Mechanism of Microbial Colonies

NASA Astrophysics Data System (ADS)

Zhu, Minhui; Martini, K. Michael; Kim, Neil H.; Sherer, Nicholas; Lee, Jia Gloria; Kuhlman, Thomas; Goldenfeld, Nigel

Experiments on nutrient-limited E. coli colonies, growing on agar gel from single cells reveal a power-law distribution of sizes, both during the growth process and in the final stage when growth has ceased. We developed a Python simulation to study the growth mechanism of the bacterial population and thus understand the broad details of the experimental findings. The simulation takes into account nutrient uptake, metabolic function, growth and cell division. Bacteria are modeled in two dimensions as hard circle-capped cylinders with steric interactions and elastic stress dependent growth characteristics. Nutrient is able to diffuse within and between the colonies. The mechanism of microbial colony growth involves reproduction of cells within the colonies and the merging of different colonies. We report results on the dynamic scaling laws and final state size distribution, that capture in semi-quantitative detail the trends observed in experiment. Supported by NSF Grant 0822613.

Detection system for a gas chromatograph. [. cap alpha. -methylnaphthalene,. beta. -methylnapthalene

DOEpatents

Hayes, J.M.; Small, G.J.

1982-04-26

A method and apparatus are described for the quantitative analysis of vaporizable compounds, and in particular of polycyclic aromatic hydrocarbons which may be induced to fluoresce. The sample to be analyzed is injected into a gas chromatography column and is eluted through a narrow orifice into a vacuum chamber. The free expansion of the eluted sample into the vacuum chamber creates a supersonic molecular beam in which the sample molecules are cooled to the extent that the excited vibrational and rotational levels are substantially depopulated. The cooled molecules, when induced to fluoresce by laser excitation, give greatly simplified spectra suitable for analytical purposes. The laser induced fluorimetry provides great selectivity, and the gas chromatograph provides quantitative transfer of the sample to the molecular beam. 3 figures, 2 tables.

Screening of beta-glucan contents in commercially cultivated and wild growing mushrooms.

PubMed

Sari, Miriam; Prange, Alexander; Lelley, Jan I; Hambitzer, Reinhard

2017-02-01

Mushrooms have unique sensory properties and nutritional values as well as health benefits due to their bioactive compounds, especially beta-glucans. Well-known edible and medicinal mushroom species as well as uncommon or unknown species representing interesting sources of bioactive beta-glucans have been widely studied. Commercially cultivated and wild growing mushrooms were analysed for their beta-glucan contents. Enzymatic determinations of all glucans, alpha-glucans and beta-glucans in 39 mushrooms species were performed, leading to very remarkable results. Many wild growing species present high beta-glucan contents, especially Bracket fungi. The well-known cultivated species Agaricus bisporus, Lentinula edodes and Cantharellus cibarius as well as most screened wild growing species show higher glucan contents in their stipes than caps. Copyright © 2016 Elsevier Ltd. All rights reserved.

Observations of 85. cap alpha. recombination lines from M16

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

Higgs, L.A.; Doherty, L.H.; MacLeod, J.M.

1979-01-01

Hydrogen and helium recombination-line observations have been made at eight positions in M16. These observations are compatible with a two-component model of the ionized gas, one component being an extended low-excitation region, the other being a higher-excitation region (with the helium ionized) at a radial velocity about 10 km s/sup -1/ greater than the mean velocity of the first component. The observed radial-velocity variations in the first component appear to be related to streaming motions from ionization fronts. The helium line emission is at a velocity comparable to that of the hottest exciting stars. The continuum radio emission is verymore » low considering the number of O stars in the nebula, indicating that it is probably density bounded.« less

POLYMERIZATION OF /cap alpha/-METHYLSTYRENE BY ELECTRON IRRADIATION (in German)

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

Braun, D.; Heufer, G.; Seufert, W.

1964-01-01

Ampoules of alpha -methylstyrene sealed under vacuum were irradiated with 1-Mev electrons in a type JS Van de Graaff generator; comparative experiments with gamma rays were carried out with a /sup 60/Co source of 3000 deg C. High doses of electrons (ca. 10/sup 8/ rad) are necessary for polymerization. The conversion is graphed as a function of dose at 0 deg C; it reaches a maximum plateau of 65% at 4 x 10/sup 8/ rad; this may point to radiolysis of the polymer at doses above this. Polymerization conversion increases with decreasing dose rate, when dose and temperature are heldmore » constant; and conversion increases with decreasing temperature (22% at --22 deg C; 10% at 15 deg C; <1% at 60 deg C), as has been found with gamma rays. In the solid state between --40 deg C and --80 deg C the maximum yield is only about 5%. The molecular weights of all poly- alpha -methylstyrenes thus formed lie between 3000 and 12,000, independently of dose rate and temperature. All polymethylstyrenes formed in the liquid state have approximately the same tacticity independent of temperature (isotactic about 20%; syndiotactic about 80%). This corresponds to the tacticity of polymers formed cationically with Lewis acids. In the solid state the tacticity is: isotactic 38%, syndiotactic, 62%, comparable with the tacticity of anionic polymerization. In the liquid state the tacticity and the sensitivity towards water indicate a cationic mechanism for the reaction. NMR studies also indicate a cationic mechanism. (BBB)« less

An agent-based model for an air emissions cap and trade program: A case study in Taiwan.

PubMed

Huang, Hsing-Fu; Ma, Hwong-Wen

2016-12-01

To determine the actual status of individuals in a system and the trading interaction between polluters, this study uses an agent-based model to set up a virtual world that represents the Kaohsiung and Pingtung regions in Taiwan, which are under the country's air emissions cap and trade program. The model can simulate each controlled industry's dynamic behavioral condition with the bottom-up method and can investigate the impact of the program and determine the industry's emissions reduction and trading condition. This model can be used elastically to predict the impact of the trading market through adjusting different settings of the program rules or combining the settings with other measures. The simulation results show that the emissions trading market has an oversupply, but we find that the market trading amounts are low. Additionally, we find that increasing the air pollution fee and offset rate restrains the agents' trading decision, according to the simulation results of each scenario. In particular, NO x and SO x trading amounts are easily impacted by the pollution fee, reduction rate, and offset rate. Also, the more transparent the market, the more it can help polluters trade. Therefore, if authorities want to intervene in the emissions trading market, they must be careful in adjusting the air pollution fee and program rules; otherwise, the trading market system cannot work effectively. We also suggest setting up a trading platform to help the dealers negotiate successfully. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure and Properties of Titanium Tantalum Alloys for Biocompatibility

NASA Astrophysics Data System (ADS)

Huber, Daniel E.

In this thesis, the phase stability and elastic modulus of Ti-Ta simple binary alloys as well as alloys with small additions of ternary elements have been studied. The binary alloy from a nominal 8 to 28 wt.% Ta was first explored using a combinatorial approach. This approach included Laser Engineered Net Shape (LENSTM) processing of materials and subsequent characterization by instrumented indentation and site specific Transmission Electron Microscopy (TEM). The composition range of 15 to 75 wt.% Ta was further explored by more traditional methods that included vacuum arc melting high purity elements, X-Ray Diffraction (XRD) and modulus measurements made by ultrasonic methods. Beyond the simple binary, alloys with low levels of ternary elements, oxygen, aluminum, zirconium and small additions of rare earth oxides were investigated. The crystal structure with space group Cmcm was chosen for it applicability with P63/mmc and Im-3¯m sub group / super group symmetry. This provides a consistent crystal structure framework for the purpose of studying the alpha to beta transformation pathway and associated alpha' and alpha'' martensitic phases. In this case, the pathway is defined by both the lattice parameters and the value of the parameter "y", where the parameter "y" describes the atomic positions of the [002]alpha plane. It was found that the lattice parameter changes in the Ti-Ta binary alloys are similar to structures reported for compositions in the Ti-Nb system of similar atomic percentages. Although samples produced by the LENSTM; process and characterized by instrumented indentation demonstrated the correct trends in modulus behavior, absolute agreement was not seen with modulus values published in literature. Alloys of the binary Ti-Ta system produced from high purity materials do indeed show close agreement with literature where there exist two minima of modulus near the compositions of Ti-28Ta wt.% and Ti-68Ta wt.%. These two minima occur at the discreet boundary between alpha' / alpha'' and alpha'' / beta respectively. The role of oxygen as an alloying addition was studied as it relates to the stability of alpha' and alpha'' martensite, here it was found that oxygen will stabilize alpha' yet cause an increase in the Young's modulus. Rare earth additions to getter interstitial oxygen in the high purity materials show no further reduction in modulus. Conversely, additions of another alpha stabilizer, Al, proved to lower the alpha' stability, with one composition exhibiting a modulus as low as 53 GPa. Zirconium being a neutral element regarding alpha and beta stability slightly changed the structure and lattice parameter, while making a little or no difference in the observed modulus. Observations by TEM of quenched specimens indicate the rise in modulus observed between the two minima is not caused the appearance of o. Rather weak o reflections were observed in Ti-65Ta wt.% in the as arc-melted condition and on annealing for 450°C for 24 hours. Precipitates of o were not clearly identified by dark-field TEM imaging. High Resolution Scanning Transmission Electron Microscopy (HRSTEM) of the aged specimen indicated that o might exist as 3-5nm particles.

Sequence variations of the alpha-globin genes: scanning of high CG content genes with DHPLC and DG-DGGE.

PubMed

Lacerra, Giuseppina; Fiorito, Mirella; Musollino, Gennaro; Di Noce, Francesca; Esposito, Maria; Nigro, Vincenzo; Gaudiano, Carlo; Carestia, Clementina

2004-10-01

The alpha-globin chains are encoded by two duplicated genes (HBA2 and HBA1, 5'-3') showing overall sequence homology >96% and average CG content >60%. alpha-Thalassemia, the most prevalent worldwide autosomal recessive disorder, is a hereditary anemia caused by sequence variations of these genes in about 25% of carriers. We evaluated the overall sensitivity and suitability of DHPLC and DG-DGGE in scanning both the alpha-globin genes by carrying out a retrospective analysis of 19 variant alleles in 29 genotypes. The HBA2 alleles c.1A>G, c.79G>A, and c.281T>G, and the HBA1 allele c.475C>A were new. Three pathogenic sequence variations were associated in cis with nonpathogenic variations in all families studied; they were the HBA2 variation c.2T>C associated with c.-24C>G, and the HBA2 variations c.391G>C and c.427T>C, both associated with c.565G>A. We set up original experimental conditions for DHPLC and DG-DGGE and analyzed 10 normal subjects, 46 heterozygotes, seven homozygotes, seven compound heterozygotes, and six compound heterozygotes for a hybrid gene. Both the methodologies gave reproducible results and no false-positive was detected. DHPLC showed 100% sensitivity and DG-DGGE nearly 90%. About 100% of the sequence from the cap site to the polyA addition site could be scanned by DHPLC, about 87% by DG-DGGE. It is noteworthy that the three most common pathogenic sequence variations (HBA2 alleles c.2T>C, c.95+2_95+6del, and c.523A>G) were unambiguously detected by both the methodologies. Genotype diagnosis must be confirmed with PCR sequencing of single amplicons or with an allele-specific method. This study can be helpful for scanning genes with high CG content and offers a model suitable for duplicated genes with high homology. Copyright 2004 Wiley-Liss, Inc.

Effects of Nd:YAG laser-heated metal cap on human platelets in vitro

NASA Astrophysics Data System (ADS)

Liu, Xia; Guo, You-chi

1993-03-01

Human platelet-rich plasma (PRP) was irradiated in vitro with a fiberoptic Nd:YAG laser-heated metal cap to study its effects on platelets. The energy of the laser was 5 and 10 watts with an irradiation time of 0, 3, 6, and 9 seconds and 14 watts with an irradiation time of 0, 3, 4, and 5 seconds, respectively. The irradiated PRPs were analyzed for platelet count, aggregation reaction, thromboxane (TX)B2 measurement and electron microscopy. Various degrees of decrease in platelet count were observed in all groups. Except the 5Wx3S group, the other groups showed an increase in the maximum aggregation rate of platelets, which corresponded to the enhancement of TXB2 formation. It was also demonstrated by a transmission electron microscopy in 10Wx3S, 10Wx6S, 10Wx9S, 14Wx3S, 14Wx4S, and 14Wx5S energy groups that alpha- and dense-particles in irradiated platelets became sparse in number or even disappeared, less electron density, irregularity in size and shape, and a tendency for these particles to cluster around platelet membranes and open canalicular systems, which dilated apparently. Furthermore, scanning electron microscopy depicted the appearance of short and thick pseudopods on the surfaces of some irradiated platelets and an increase in the axis rate in most of the irradiated platelets.

Burden of hospitalized childhood community-acquired pneumonia: A retrospective cross-sectional study in Vietnam, Malaysia, Indonesia and the Republic of Korea

PubMed Central

Tan, Kah Kee; Dang, Duc Anh; Kim, Ki Hwan; Kartasasmita, Cissy; Zhang, Xu-Hao; Shafi, Fakrudeen; Yu, Ta-Wen; Ledesma, Emilio; Meyer, Nadia

2018-01-01

ABSTRACT Background: Few studies describe the community-acquired pneumonia (CAP) burden in children in Asia. We estimated the proportion of all CAP hospitalizations in children from nine hospitals across the Republic of Korea (high-income), Indonesia, Malaysia (middle-income), and Vietnam (low/middle-income). Methods: Over a one or two-year period, children <5 years hospitalized with CAP were identified using ICD-10 discharge codes. Cases were matched to standardized definitions of suspected (S-CAP), confirmed (C-CAP), or bacterial CAP (B-CAP) used in a pneumococcal conjugate vaccine efficacy study (COMPAS). Median total direct medical costs of CAP-related hospitalizations were calculated. Results: Vietnam (three centers): 7591 CAP episodes were identified with 4.3% (95% confidence interval 4.2;4.4) S-CAP, 3.3% (3.2;3.4) C-CAP and 1.4% (1.3;1.4) B-CAP episodes of all-cause hospitalization in children aged <5 years. The B-CAP case fatality rate (CFR) was 1.3%. Malaysia (two centers): 1027 CAP episodes were identified with 2.7% (2.6;2.9); 2.6% (2.4;2.8); 0.04% (0.04;0.1) due to S-CAP, C-CAP, and B-CAP, respectively. One child with B-CAP died. Indonesia (one center): 960 CAP episodes identified with 18.0% (17.0;19.1); 16.8% (15.8;17.9); 0.3% (0.2;0.4) due to S-CAP, C-CAP, and B-CAP, respectively. The B-CAP CFR was 20%. Korea (three centers): 3151 CAP episodes were identified with 21.1% (20.4;21.7); 11.8% (11.2;12.3); 2.4% (2.1;2.7) due to S-CAP, C-CAP, and B-CAP, respectively. There were no deaths. Costs: CAP-related hospitalization costs were highest for B-CAP episodes: 145.00 (Vietnam) to 1013.3 USD (Korea) per episode. Conclusion: CAP hospitalization causes an important health and cost burden in all four countries studied (NMRR-12-50-10793). PMID:29125809

Volume integrals associated with the inhomogeneous Helmholtz equation. Part 1: Ellipsoidal region

NASA Technical Reports Server (NTRS)

Fu, L. S.; Mura, T.

1983-01-01

Problems of wave phenomena in fields of acoustics, electromagnetics and elasticity are often reduced to an integration of the inhomogeneous Helmholtz equation. Results are presented for volume integrals associated with the Helmholtz operator, nabla(2) to alpha(2), for the case of an ellipsoidal region. By using appropriate Taylor series expansions and multinomial theorem, these volume integrals are obtained in series form for regions r 4' and r r', where r and r' are distances from the origin to the point of observation and source, respectively. Derivatives of these integrals are easily evaluated. When the wave number approaches zero, the results reduce directly to the potentials of variable densities.

Direct processes in 54-MeV Li-7 breakup reactions on C-12 and Au-197 targets, and the extraction of astrophysical cross sections

NASA Astrophysics Data System (ADS)

Gazes, S. B.; Mason, J. E.; Roberts, R. B.; Teichmann, S. G.

1992-01-01

Strong direct processes were observed for elastic breakup in 54-MeV Li-7 + C-12, Au-197 reactions. In the case of C-12, the observed Li-7 to alpha + t direct-breakup yield was significantly larger than predicted by a Coulomb-breakup calculation, indicating the importance of the nuclear field. For Au-197, final-state interactions produced a strong distortion in the fragment energy spectra, as well as a modulation of the coincidence efficiency for different detector geometries. Such Coulomb effects are found to severely complicate the extraction of radiative-capture cross sections from direct-breakup data.

Flavor and baryon quantum numbers and their nondiffractive renormalizations of the Pomeron

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

Dash, J.W.; Jones, S.T.; Manesis, E.K.

We present a theoretical review and a detailed phonomenological description of the ''flavoring'' of the bare Pomeron pole at t = 0 (i.e., the nondiffractive renormalization of its multiperipheral unitarity sum by strange quarks, charmed quarks, diquarks,...) from an ''unflavored'' intercept alpha-circumflex = 0.85 to a ''flavored'' intercept ..cap alpha.. approx. = 1.08. Experimentally, flavoring effects seem to converge rapidly; hence this number is probably close to the bare intercept of the Reggeon field theory. We treat NN, ..pi..N, and KN total cross sections and real to imaginary amplitude ratios. We do not observe oscillations. We pay particular attention tomore » 2sigma/sub K/N - sigma/sub piN/ which rises monotonically. We present a closely related combination of inelastic diffraction cross sections which decreases monotonically, indicating that vacuum amplitudes are not simply the sum of a Pomeron pole and an ideally mixed f. In fact we argue that a Pomeron + f structure is neither compatible with flavoring nor with schemes in which flavoring is somehow absorbed away. In contrast, flavoring is required for consistency with experiment by the Chew-Rosenzweig hypothesis of the Pomeron-f identity. We close with a description of flavoring threshold effects on the Reggeon field theory at current energies.« less

Effect of interferons and other biological response modifiers (BRMS) on macrophage-mediated inhibition of Listeria monocytogenes

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

Badger, A.M.; Swift, B.; Sung, C.P.

1986-03-05

Recombinant murine gamma interferon (IFN-..gamma..) activates oil elicited C57BL/6 peritoneal macrophages to inhibit the growth of Listeria. Maximum activity is obtained with 10-20 units/ml, can be demonstrated in the absence of antibiotics and is not due to LPS contamination. Studies of the kinetics of this phenomenon demonstrate that a 30 minute incubation with IFN-..gamma.. is sufficient to initiate the antiproliferative state and full activity can be obtained with a 4 hour incubation. Alpha/beta interferon (IFN-..cap alpha../..beta..) is also active but requires 100X more units to obtain equivalent activity. The evaluation of a number of other BRMS demonstrated that MDP andmore » LPS could stimulate phagocytosis of Listeria but could not inhibit their growth. Bestatin, tuftsin, Con A, A23187 and Poly I:C did not stimulate either phagocytosis or growth inhibitory activity. These compounds were also tested for their ability to enhance the release of superoxide anion from PMA stimulated macrophages. With the exception of tuftsin and bestatin all of the BRMS tested were able to enhance the production of oxidative burst products confirming the findings of others of the dissociation between the two functions.« less

Formation of [b3 - 1 + cat]+ ions from metal-cationized tetrapeptides containing beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid residues.

PubMed

Osburn, Sandra M; Ochola, Sila O; Talaty, Erach R; Van Stipdonk, Michael J

2008-11-01

The presence and position of a single beta-alanine (betaA), gamma-aminobutyric acid (gammaABu) or epsilon-aminocaproic acid (Cap) residue has been shown to have a significant influence on the formation of b(n)+ and y(n)+ product ions from a series of model, protonated peptides. In this study, we examined the effect of the same residues on the formation of analogous [b3 - 1 + cat]+ products from metal (Li+, Na+ and Ag+)-cationized peptides. The larger amino acids suppress formation of b3+ from protonated peptides with general sequence AAXG (where X = beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid), presumably because of the prohibitive effect of larger cyclic intermediates in the 'oxazolone' pathway. However, abundant [b3 - 1 + cat]+ products are generated from metal-cationized versions of AAXG. Using a group of deuterium-labeled and exchanged peptides, we found that formation of [b3 - 1 + cat]+ involves transfer of either amide or alpha-carbon position H atoms, and the tendency to transfer the atom from the alpha-carbon position increases with the size of the amino acid in position X. To account for the transfer of the H atom, a mechanism involving formation of a ketene product as [b3 - 1 + cat]+ is proposed.

The legumin gene family: structure of a B type gene of Vicia faba and a possible legumin gene specific regulatory element.

PubMed Central

Bäumlein, H; Wobus, U; Pustell, J; Kafatos, F C

1986-01-01

The field bean, Vicia faba L. var. minor, possesses two sub-families of 11 S legumin genes named A and B. We isolated from a genomic library a B-type gene (LeB4) and determined its primary DNA sequence. Gene LeB4 codes for a 484 amino acid residue prepropolypeptide, encompassing a signal peptide of 22 amino acid residues, an acidic, very hydrophilic alpha-chain of 281 residues and a basic, somewhat hydrophobic beta-chain of 181 residues. The latter two coding regions are immediately contiguous, but each is interrupted by a short intron. Type A legumin genes from soybean and pea are known to have introns in the same two positions, in addition to an extra intron (within the alpha-coding sequence). Sequence comparisons of legumin genes from these three plants revealed a highly conserved sequence element of at least 28 bp, centered at approximately 100 bp upstream of each cap site. The element is absent from the equivalent position of all non-legumin and other plant and fungal genes examined. We tentatively name this element "legumin box" and suggest that it may have a function in the regulation of legumin gene expression. PMID:3960730

Impact resistance of oil-immersed lignum vitae

NASA Astrophysics Data System (ADS)

Yin, Wei; Shan, Lei; Lu, Hongyu; Zheng, Yelong; Han, Zhiwu; Tian, Yu

2016-07-01

Biological materials immersed in vegetable and mineral oil, such as rattan armor and wooden sleepers, have been extensively used since ancient times because of their excellent mechanical properties. This study quantitatively investigated the viscoelasticity and tribological performance of lignum vitae immersed in poly-alpha-olefin (PAO) and tung oils (Aleuritesfordii Hemsl.) to reveal the mechanism of impact resistance. The acceleration of samples immersed in tung oil was higher than that of dry and PAO-immersed samples in the first impact. The elastic modulus of the samples immersed in tung oil increased slightly. The impact damage on the samples immersed in tung oil was reduced because of the low friction coefficient (0.07) resulted in a low wear rate. The extent of impact damage on the samples immersed in tung oil was approximately 34% and 58% lower than that on the dry and PAO oil-immersed samples, respectively, under an angle of 20° and a height of 10 cm. The impact damage on the PAO-immersed samples was reduced because of low friction coefficient. However, impact damage increased because of large elastic modulus. The findings of this study can serve as a reference for the application of modified biological materials with high strength and wear resistance.

Impact resistance of oil-immersed lignum vitae.

PubMed

Yin, Wei; Shan, Lei; Lu, Hongyu; Zheng, Yelong; Han, Zhiwu; Tian, Yu

2016-07-18

Biological materials immersed in vegetable and mineral oil, such as rattan armor and wooden sleepers, have been extensively used since ancient times because of their excellent mechanical properties. This study quantitatively investigated the viscoelasticity and tribological performance of lignum vitae immersed in poly-alpha-olefin (PAO) and tung oils (Aleuritesfordii Hemsl.) to reveal the mechanism of impact resistance. The acceleration of samples immersed in tung oil was higher than that of dry and PAO-immersed samples in the first impact. The elastic modulus of the samples immersed in tung oil increased slightly. The impact damage on the samples immersed in tung oil was reduced because of the low friction coefficient (0.07) resulted in a low wear rate. The extent of impact damage on the samples immersed in tung oil was approximately 34% and 58% lower than that on the dry and PAO oil-immersed samples, respectively, under an angle of 20° and a height of 10 cm. The impact damage on the PAO-immersed samples was reduced because of low friction coefficient. However, impact damage increased because of large elastic modulus. The findings of this study can serve as a reference for the application of modified biological materials with high strength and wear resistance.

Extrinsic effects in twinned ferroelectric polycrystals

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

Perez, Rafel; Garcia, Jose E.; Albareda, Alfons

2007-08-15

The structure of medium-grain piezoelectric ceramics often consists of alternate lamellae of non-180 deg. domains. In this work, the extrinsic effects of the electric and elastic fields on such structures are studied. A description of the extrinsic behavior of a single grain is given, and it is shown that the relations between piezoelectric and dielectric or elastic constants must be independent of the wall mobility, being solely dependent on the relation between spontaneous polarization and strain. By using an appropriate coordinate system, the conditions under which the intrinsic and extrinsic effects can be added are analyzed. The linear global behaviormore » of a grain can then be described as a function of its orientation and of two additional parameters: the lack of equilibrium between domains {alpha} and its mean thickness d. The basis is established to describe the state of a ceramic through a distribution function that accounts for domain orientation and which depends on the poling, fatigue, and ageing of the sample. Finally, the goodness of the model is analyzed, although some aspects must be still modified in order to describe the overall behavior of the ceramic.« less

Maturational changes in extracellular matrix and lung tissue mechanics.

PubMed

Tanaka, R; Al-Jamal, R; Ludwig, M S

2001-11-01

The viscoelastic properties of the pulmonary parenchyma change rapidly postparturition. We compared changes in mechanical properties with changes in tissue composition of rat lung parenchymal strips in three groups of Sprague-Dawley rats: baby (B; 10-14 days), young (Y; approximately 3 wk), and adult (A; approximately 8 wk). Strips were suspended in an organ bath, and resistance (R), elastance (E), and hysteresivity (eta) were calculated during sinusoidal oscillations before and after the addition of acetylcholine (ACh) (10(-3) M). Strips were then fixed in formalin, and sections were stained with hematoxylin and eosin, Verhoff's elastic stain, or Van Gieson's picric acid-fuchsin stain for collagen. The volume proportion of collagen (%Col), the length density of elastic fibers (L(V)/Pr(alv)), and the arithmetic mean thickness of alveolar septae (T(a)) were calculated by morphometry. Tissue was also stained for alpha-smooth muscle actin (ASMA), and the volume proportion of ASMA (%ASMA) was calculated. Hyaluronic acid (HA) was quantitated by radioimmunoassay in separate strips. R and E in B strips were significantly higher, whereas eta was significantly smaller than in Y or A strips. Changes in these parameters with ACh were greater in B strips. T(a), %ASMA, and HA were greatest in B strips, whereas %Col and L(V)/Pr(alv) were least. There were significant positive correlations between R and E vs. T(a) and between percent change in R and eta post-ACh vs. T(a) and vs. %ASMA, and significant negative correlations between R and E vs. %Col and vs. L(V)/Pr(alv) and percent increase in all three mechanical parameters post-ACh vs. %Col. These data suggest that the relatively high stiffness, R, and contractile responsiveness of parenchymal tissues observed in newborns are not directly attributable to the amount of collagen and elastic fibers in the tissue, but rather they are related to the thickened alveolar wall and the relatively greater percent of contractile cells.

78 FR 18335 - Central Arizona Project-Rate Order No. WAPA-158

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... Project, reflected in Transmission Service Rate Schedules CAP-FT2, CAP-NFT2, and CAP-NITS2, from January 1... existing Rate Schedules CAP-FT2, CAP-NFT2, CAP-NITS2 under Rate Order No. WAPA-124,\\1\\ were approved for a... Transmission Service Rate Schedules CAP-FT2, CAP-NFT2, and CAP-NITS2 on an interim basis effective as of...

The copper dependent-lysyl oxidases contribute to the pathogenesis of pulmonary emphysema in chronic obstructive pulmonary disease patients.

PubMed

Besiktepe, Neziha; Kayalar, Ozgecan; Ersen, Ezel; Oztay, Fusun

2017-12-01

Abnormalities in the elastic fiber biology are seen in pulmonary emphysema (PE). The copper-dependent lysyl oxidases regulate the production and accumulation of elastic fibers in the connective tissue. This study focused on the relationship between lysyl oxidase (LOX), LOX-like protein 1 (LOXL1), and LOXL2 and PE pathogenesis. Lung samples with or without PE from patients with chronic obstructive lung disease (n=35) were used. Protein levels of elastin, LOX, LOXL1, LOXL2, hypoxia inducible factor 1-alpha (HIF-1α), copper metabolism domain containing-1 (COMMD1), and phosphatase and tensin homolog (PTEN) were assayed using microscopic and biochemical methods The emphysematous areas were characterized by enlargement of the alveoli, destruction of the alveolar structure, accumulation of macrophages in the alveolar lumens, and showed increased HIF-1α immunoreactivity. Additionally, the emphysematous areas had significantly lower elastin, LOX, LOXL1, LOXL2, HIF-1α, COMMD1, and PTEN protein levels than the non-emphysematous areas. We suppose that the reductions in the HIF-1α levels led to decreases in the protein levels of active LOX, LOXL1, and LOXL2. These decreases might cause abnormalities in the elastic fiber biology. HIF-1α activation induced by decreased COMMD1 and protease activation induced by decreased PTEN might contribute to the development of PE. Finally, methods aimed at increasing the protein levels of LOXs, COMMD1 and PTEN might be effective for treating PE. Copyright © 2017 Elsevier GmbH. All rights reserved.

Chios mastic treatment of patients with active Crohn’s disease

PubMed Central

Kaliora, Andriana C; Stathopoulou, Maria G; Triantafillidis, John K; Dedoussis, George VZ; Andrikopoulos, Nikolaos K

2007-01-01

AIM: To evaluate the effectiveness of mastic administration on the clinical course and plasma inflammatory mediators of patients with active Crohn’s disease (CD). METHODS: This pilot study was conducted in patients with established mild to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Ten patients and 8 controls were recruited for a 4-wk treatment with mastic caps (6 caps/d, 0.37 g/cap). All patients successfully completed the protocol. CD Activity Index (CDAI), Nutritional Risk Index (NRI), C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), and total antioxidant potential (TAP) were evaluated in the plasma at baseline and at the end of the treatment period. Results were expressed as mean values ± SE and P < 0.05 was considered to indicate statistical significance. RESULTS: Patients exhibited significant reduction of CDAI (222.9 ± 18.7 vs 136.3 ± 12.3, P = 0.05) as compared to pretreament values. Plasma IL-6 was significantly decreased (21.2 ± 9.3 pg/mL vs 7.2 ± 2.8 pg/ mL, P = 0.027), and so did CRP (40.3 ± 13.1 mg/mL vs 19.7 ± 5.5, P = 0.028). TAP was significantly increased (0.15 ± 0.09 vs 0.57 ± 0.15 mmol/L uric acid, P = 0.036). No patient or control exhibited any kind of side effects. CONCLUSION: The results suggest that mastic significantly decreased the activity index and the plasma levels of IL-6 and CRP in patients with mildly to moderately active CD. Further double-blind, placebo-controlled studies in a larger number of patients are required to clarify the role of this natural product in the treatment of patients with CD. PMID:17278198

The Density of the North Polar Layered Deposit from Gravity and Topography

NASA Astrophysics Data System (ADS)

Ojha, L.; Lewis, K. W.

2017-12-01

The North Polar Layered Deposit (NPLD) of Mars is a vast reservoir of water ice with a volume of 1.14 million km3. Radar data indicates that the ice in the NPLD is extremely pure with dust content between 5 % to 10 %, however the radar data has not been able to put a direct constraint on the density of the NPLD. Here, we localize the gravity and topography signature of the NPLD and place a direct constraint on its density. We performed a grid search by generating admittance spectrum at each latitude and longitude between 75° N to 90° N and 0° E to 360° E, using a spherical cap of angular radius () of 7°, and a harmonic-bandwidth of the localization window Lwin of 37°. A region between Gemina Lingula and Planum Boreum was found to possesss an adequate correlation between gravity and topography. The estimated admittance spectra were compared with synthetic admittance spectra to constrain the load-density and the elastic thickness of the lithosphere. We constructed forward models by assuming that the lithosphere is a thin shell that deforms elastically in response to surface loads. We find that the bulk density of the NPLD ranges between 1000 to 1100 kg.m-3. Assuming a grain density of 3000 kg.m-3 for dust, the NPLD region within our localized window can contain dust content between 3 - 8 %, which is in an excellent agreement with the radar data.

The self-absorption effect of gamma rays in /sup 239/Pu

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

Hsu, Hsiao-Hua

1989-01-01

Nuclear materials assay with gamma-ray spectrum measurement is a well-established method for safeguards. However, for a thick source, the self-absorption of characteristic low-energy gamma rays has been a handicap to accurate assay. I have carried out Monte Carlo simulations to study this effect using the /sup 239/Pu ..cap alpha..-decay gamma-ray spectrum as an example. The thickness of a plutonium metal source can be considered a function of gamma-ray intensity ratios. In a practical application, gamma-ray intensity ratios can be obtained from a measured spectrum. With the help of calculated curves, scientists can find the source thickness and make corrections tomore » gamma-ray intensities, which then lead to an accurate quantitative determination of radioactive isotopes in the material. 2 refs., 9 figs.« less

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

Bernstein, S.E.

Hereditary anemias of mice are the chief objects of investigation, specificially four macrocytic anemias, 3 types of hemolytic anemia, nonhemolytic microcytic anemia, transitory siderocytic anemia, sex-linked iron-transport anemia, the autoimmune hemolytic anemia of NZB mice, an ..cap alpha..-thalassemia and a new hypochromic anemia with hemochromatosis. New types of anemia may be analyzed as new mutations appear. Three new mutations have been identified during the past 18 months. These anemias are studied through characterization of peripheral blood values, determinations of radiosensitivity under a variety of conditions, measurements of iron metabolism and heme synthesis, study of normal and abnormal erythrocyte membrane proteins,more » histological and biochemical characterization of blood-forming tissue, functional tests of the stem-cell component, examination of responses to erythroid stimuli, and transplantation of tissue and parabiosis between individuals of differently affected genotypes. 31 refs.« less

Reactions of bis(2,2,3,3-tetrafluoropropyl) phosphorisocyanatidite and tris(2,2,3,3-tetrafluoropropyl) phosphite with carbonyl compounds

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

Konovalova, I.V.; Burnaeva, L.A.; Khusnutdinova, E.K.

1986-11-20

The authors studied the reactions of bis(2,2,3,3-tetrafluoropropyl) phosphorisocyanatidite with carbonyl and ..cap alpha..-halo carbonyl compounds, namely, benzil, ethyl phenylglyoxylate, methyl chloropyruvate, and diethyl (trichloroacetyl)phosphonate. The reaction of bis(2,2,3,3-tetrachloropropyl) phosphorisocyanatidite with benzil required severe conditions (3 h at 40/sup 0/C). The /sup 31/P NMR spectrum of the reaction mixture contains two signals at 12 and -55 ppm, which probably belong to the azaphospholine and its dimer. By vacuum fractionation they isolated a thick liquid, the /sup 31/P NMR spectrum of which contains a signal 12 ppm corresponding to 5-benzoyl-4-oxo-5-phenyl-2,2-bis(2,2,3,3-tetrafluoropropoxy)-..delta../sup 2/-1,3,2lambda/sup 5/-oxazaphospholine.

Magnetic ordering in Ce-La and Nd-La alloys

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

Petersen, T.S.; Legvold, S.; Gschneidner, K.A. Jr.

1978-03-01

Heat capacity, magnetic susceptibility, and electrical resistivity measurements have been made on a wide ranging set of Ce-La and Nd-La alloys. In the case of Ce it is found that less than 5 at. % of La will prevent the ..beta.. (dhcp) to ..cap alpha.. (collapsed fcc) transition at T9 or approx. =50 K. In the case of Nd-La only the dhcp allotrope is formed. Two magnetic ordering temperatures have been found for many of the samples. These are believed to be caused by antiferromagnetic ordering on the two different atomic sites in the dhcp structure, cubic and hexagonal. Inmore » both sets of alloys the two ordering temperatures coalesce into one for La concentrations > or approx. =30%. Additional magnetic features in Ce-La alloys are explained by the formation of the fcc phase.« less

CapZyme-Seq Comprehensively Defines Promoter-Sequence Determinants for RNA 5' Capping with NAD.

PubMed

Vvedenskaya, Irina O; Bird, Jeremy G; Zhang, Yuanchao; Zhang, Yu; Jiao, Xinfu; Barvík, Ivan; Krásný, Libor; Kiledjian, Megerditch; Taylor, Deanne M; Ebright, Richard H; Nickels, Bryce E

2018-05-03

Nucleoside-containing metabolites such as NAD + can be incorporated as 5' caps on RNA by serving as non-canonical initiating nucleotides (NCINs) for transcription initiation by RNA polymerase (RNAP). Here, we report CapZyme-seq, a high-throughput-sequencing method that employs NCIN-decapping enzymes NudC and Rai1 to detect and quantify NCIN-capped RNA. By combining CapZyme-seq with multiplexed transcriptomics, we determine efficiencies of NAD + capping by Escherichia coli RNAP for ∼16,000 promoter sequences. The results define preferred transcription start site (TSS) positions for NAD + capping and define a consensus promoter sequence for NAD + capping: HRRASWW (TSS underlined). By applying CapZyme-seq to E. coli total cellular RNA, we establish that sequence determinants for NCIN capping in vivo match the NAD + -capping consensus defined in vitro, and we identify and quantify NCIN-capped small RNAs (sRNAs). Our findings define the promoter-sequence determinants for NCIN capping with NAD + and provide a general method for analysis of NCIN capping in vitro and in vivo. Copyright © 2018 Elsevier Inc. All rights reserved.

High-pressure jet cutters improve capping operations

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

Abel, L.W.; Campbell, P.J.; Bowden, J.R. Sr.

1995-05-08

Advances in abrasive cutting technology have improved the methods for removing damaged equipment and preparing wellheads for capping. This technology, much of which was refined during well control operations in Kuwait in 1991, can improve the safety and efficiency of capping jobs by cutting wellheads or casing quickly and cleanly. The majority of well control jobs involve one of three types of capping operations: capping to a flange, capping by installing a wellhead, or capping to a casing stub. Capping operations are often the first major step in regaining control of the well during blowout intervention. Proper planning of amore » capping operation must take into account the mass flow rate, combustible nature of the flow, well bore geometry, and operations in the post-capping phase of the project. The paper discusses capping vehicles, tree removal, jet cutters, capping to a flange, capping to a stub, swallowing the stub, spin-on technique, capping on fire, stinging, offshore blowouts, firefighting, pollution control, intervention equipment, and rig removal.« less

Serum tryptase level is a better predictor of systemic side effects than prostaglandin D2 metabolites during venom immunotherapy in children.

PubMed

Cichocka-Jarosz, E; Sanak, M; Szczeklik, A; Brzyski, P; Gielicz, A; Pietrzyk, J J

2011-01-01

We performed a prospective study to analyze mast cell mediators as predictors of systemic adverse reactions during rush venom-specific immunotherapy (VIT) in children. Nineteen children aged 5-17 years received VIT with Venomenhal (HALAllergy). We analyzed serum tryptase (CAP, Phadia), plasma prostaglandin (PG) D2 metabolites (9alpha, 11beta-PGF2), and urine PGD2 metabolites (9alpha, 11beta-PGF2, tetranor-PGD-M) using gas chromatography mass spectrometry before and after the rush protocol. Three boys with high baseline serum tryptase values (>7.76 g/L) (P < .001) and low 9alpha, 11beta-PGF2 concentrations developed grade III systemic adverse reactions during VIT. Baseline serum tryptase was lowest in children who had a Mueller grade II reaction (1.93 [0.36]) before VIT and highest in children with a Mueller grade III reaction (6.31 [4.80]) (P = .029). Repeated measures analysis of variance confirmed that, in children who developed systemic adverse reactions during VIT, serum tryptase was higher both before and after desensitization and increased significantly following the procedure. Analysis of PGD2 metabolites in the prediction of systemic adverse reactions during VIT was inadequate (sensitivity 67% and specificity 0.53%), whilst prediction based on serum tryptase was accurate. In children with severe systemic adverse reactions to Hymenoptera sting, the evaluation of baseline tryptase levels should be a standard procedure. Children with Apis mellifera venom allergy and baseline tryptase levels higher than 7.75 g/L are at risk of anaphylaxis during buildup. Lower baseline values of plasma and urinary PGD2 metabolite concentration in patients with systemic adverse reaction during VIT suggest that prostaglandin catabolism is altered.

All-Sky Observational Evidence for An Inverse Correlation Between Dust Temperature and Emissivity Spectral Index

NASA Technical Reports Server (NTRS)

Liang, Z.; Fixsen, D. J.; Gold, B.

2012-01-01

We show that a one-component variable-emissivity-spectral-index model (the free- model) provides more physically motivated estimates of dust temperature at the Galactic polar caps than one- or two-component fixed-emissivity-spectral-index models (fixed- models) for interstellar dust thermal emission at far-infrared and millimeter wavelengths. For the comparison we have fit all-sky one-component dust models with fixed or variable emissivity spectral index to a new and improved version of the 210-channel dust spectra from the COBE-FIRAS, the 100-240 micrometer maps from the COBE-DIRBE and the 94 GHz dust map from the WMAP. The best model, the free-alpha model, is well constrained by data at 60-3000 GHz over 86 per cent of the total sky area. It predicts dust temperature (T(sub dust)) to be 13.7-22.7 (plus or minus 1.3) K, the emissivity spectral index (alpha) to be 1.2-3.1 (plus or minus 0.3) and the optical depth (tau) to range 0.6-46 x 10(exp -5) with a 23 per cent uncertainty. Using these estimates, we present all-sky evidence for an inverse correlation between the emissivity spectral index and dust temperature, which fits the relation alpha = 1/(delta + omega (raised dot) T(sub dust) with delta = -.0.510 plus or minus 0.011 and omega = 0.059 plus or minus 0.001. This best model will be useful to cosmic microwave background experiments for removing foreground dust contamination and it can serve as an all-sky extended-frequency reference for future higher resolution dust models.

Acclimation to cold and warm temperatures is associated with differential expression of male carp blood proteins involved in acute phase and stress responses, and lipid metabolism.

PubMed

Dietrich, Mariola A; Hliwa, Piotr; Adamek, Mikołaj; Steinhagen, Dieter; Karol, Halina; Ciereszko, Andrzej

2018-05-01

The environmental temperature affects plasma biochemical indicators, antioxidant status and hematological and immunological parameters in fish. So far, only single blood proteins have been identified in response to temperature changes. The aim of this study was to compare the proteome of carp blood plasma from males acclimated to warm (30 °C) and cold (10 °C) temperatures by two-dimensional differential gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry. A total of 47 spots were found to be differentially regulated by temperature (>1.2-fold change, p < 0.05): 25 protein spots were more abundant in warm-acclimated males and 22 were enriched in cold-acclimated males. The majority of differentially regulated proteins were associated with acute phase response signalling involved in: i) activation of the complement system (complement C3-H1), ii) neutralization of proteolytic enzymes (inter-alpha inhibitor H3, fetuin, serpinA1, antithrombin, alpha2-macroglobulin), iii) scavenging of free hemoglobin and radicals (haptoglobin, Wap65 kDa), iv) clot-formation (fibrinogen beta and alpha chain, T-kininogen) and v) the host's immune response modulation (ApoA1 and ApoA2). However, quite different sets of these proteins or proteoforms were involved in response to cold and warm temperatures. In addition, cold acclimation seems to be related to the proteins involved in lipid metabolism (apolipoproteins A and 14 kDa) and stress response (corticosteroid binding globulin). We discovered a strongly regulated protein Cap31 upon cold acclimation, which can serve as a potential blood biomarker of cold response in carp. These studies significantly extend our knowledge concerning mechanisms underlying thermal adaptation in poikilotherms. Copyright © 2018. Published by Elsevier Ltd.

Histochemical Demonstration of Protein-Bound Alpha-Acylamido Carboxyl Groups

PubMed Central

Barrnett, Russell J.; Seligman, Arnold M.

1958-01-01

A method has been developed to demonstrate the alpha-acylamido carboxyl groups of protein, taking advantage of the fact that acylamido carboxyl groups are converted to ketonic carbonyls by the action of acetic anhydride and absolute pyridine. The method utilizes deparaffinized sections of tissues fixed in a variety of fixatives. Following the conversion of carboxyls to the methyl ketones, the latter are stained with 2-hydroxy-3-naphthoic acid hydrazide. Control experiments have indicated that methylation of carboxyls prevented staining, as did carbonyl reagents after the carboxyls were transformed to methyl ketones. Leucofuchsin did not stain the ketonic carbonyls, and only elastic tissue stained with 2-hydroxy-3-naphthoic acid hydrazide without the previous use of the catalyzed reaction with anhydride. A brief survey of the reaction on various tissues of the albino rat was made, and the effects of various fixatives were assayed. Of particular interest were certain sites, such as acidophiles of the anterior pituitary gland, where an intense reaction occurred. The possibility exists that certain specific proteins rich in terminal acylamido carboxyl groups, by virtue of their protein side chains or low molecular weight, may be demonstrated by this method. PMID:13525430

High-Alpha Research Vehicle Lateral-Directional Control Law Description, Analyses, and Simulation Results

NASA Technical Reports Server (NTRS)

Davidson, John B.; Murphy, Patrick C.; Lallman, Frederick J.; Hoffler, Keith D.; Bacon, Barton J.

1998-01-01

This report contains a description of a lateral-directional control law designed for the NASA High-Alpha Research Vehicle (HARV). The HARV is a F/A-18 aircraft modified to include a research flight computer, spin chute, and thrust-vectoring in the pitch and yaw axes. Two separate design tools, CRAFT and Pseudo Controls, were integrated to synthesize the lateral-directional control law. This report contains a description of the lateral-directional control law, analyses, and nonlinear simulation (batch and piloted) results. Linear analysis results include closed-loop eigenvalues, stability margins, robustness to changes in various plant parameters, and servo-elastic frequency responses. Step time responses from nonlinear batch simulation are presented and compared to design guidelines. Piloted simulation task scenarios, task guidelines, and pilot subjective ratings for the various maneuvers are discussed. Linear analysis shows that the control law meets the stability margin guidelines and is robust to stability and control parameter changes. Nonlinear batch simulation analysis shows the control law exhibits good performance and meets most of the design guidelines over the entire range of angle-of-attack. This control law (designated NASA-1A) was flight tested during the Summer of 1994 at NASA Dryden Flight Research Center.

Cradle Cap (For Parents)

MedlinePlus

... Safe Videos for Educators Search English Español Cradle Cap (Infantile Seborrheic Dermatitis) KidsHealth / For Parents / Cradle Cap ( ... many babies develop called cradle cap. About Cradle Cap Cradle cap is the common term for seborrheic ...

Core-level spectra and binding energies of transition metal nitrides by non-destructive x-ray photoelectron spectroscopy through capping layers

NASA Astrophysics Data System (ADS)

Greczynski, G.; Primetzhofer, D.; Lu, J.; Hultman, L.

2017-02-01

We present the first measurements of x-ray photoelectron spectroscopy (XPS) core level binding energies (BE:s) for the widely-applicable group IVb-VIb polycrystalline transition metal nitrides (TMN's) TiN, VN, CrN, ZrN, NbN, MoN, HfN, TaN, and WN as well as AlN and SiN, which are common components in the TMN-based alloy systems. Nitride thin film samples were grown at 400 °C by reactive dc magnetron sputtering from elemental targets in Ar/N2 atmosphere. For XPS measurements, layers are either (i) Ar+ ion-etched to remove surface oxides resulting from the air exposure during sample transfer from the growth chamber into the XPS system, or (ii) in situ capped with a few nm thick Cr or W overlayers in the deposition system prior to air-exposure and loading into the XPS instrument. Film elemental composition and phase content is thoroughly characterized with time-of-flight elastic recoil detection analysis (ToF-E ERDA), Rutherford backscattering spectrometry (RBS), and x-ray diffraction. High energy resolution core level XPS spectra acquired with monochromatic Al Kα radiation on the ISO-calibrated instrument reveal that even mild etching conditions result in the formation of a nitrogen-deficient surface layer that substantially affects the extracted binding energy values. These spectra-modifying effects of Ar+ ion bombardment increase with increasing the metal atom mass due to an increasing nitrogen-to-metal sputter yield ratio. The superior quality of the XPS spectra obtained in a non-destructive way from capped TMN films is evident from that numerous metal peaks, including Ti 2p, V 2p, Zr 3d, and Hf 4f, exhibit pronounced satellite features, in agreement with previously published spectra from layers grown and analyzed in situ. In addition, the N/metal concentration ratios are found to be 25-90% higher than those obtained from the corresponding ion-etched surfaces, and in most cases agree very well with the RBS and ToF-E ERDA values. The N 1 s BE:s extracted from capped TMN films, thus characteristic of a native surface, show a systematic trend, which contrasts with the large BE spread of literature "reference" values. Hence, non-destructive core level XPS employing capping layers provides an opportunity to obtain high-quality spectra, characteristic of virgin in situ grown and analyzed TMN films, although with larger versatility, and allows for extracting core level BE values that are more reliable than those obtained from sputter-cleaned N-deficient surfaces. Results presented here, recorded from a consistent set of binary TMN's grown under the same conditions and analyzed in the same instrument, provide a useful reference for future XPS studies of multinary materials systems allowing for true deconvolution of complex core level spectra.

Acid precipitation and food quality: Effects of dietary Al, Ca and P on bone and liver characteristics in American black ducks and mallards

USGS Publications Warehouse

Sparling, D.W.

1991-01-01

American black ducks (Anas rubripes) and mallards (A. platyrhynchos) were fed diets varying in concentrations of aluminum (Al). calcium (Ca), and phosphorus (P) for 10 weeks to identify toxic effects of Al under conditions representative of areas with acid precipitation. Femur and liver tissues were analyzed for Al. Ca, and P concentrations and structural characteristics. At two weeks of age, both species demonstrated pronounced differences in femur Al and P concentrations and femur mass from dietary Al and interaction between Ca:P regimen and Al:Low Ca:Low P enhanced Al storage and decreased P and mass in femurs. Femur Ca was lowest in the Low Ca:Low P regimen but was not affected by dietary Al. At 10 weeks, femur and liver Al continued to vary with dietary Al. Elevated Al and reduced Ca lowered modulus of elasticity. Femur P increased with elevated dietary P in black ducks. Elevated dietary P negated some of the effects of dietary A! on femur mass in black ducks. Reduced Ca concentrations weakened bones of both species and lowered both Ca and P. An array of clinical signs including lameness, discoloration of the upper mandible, complete and greenstick fractures, and death were responses to elevated Al and Ca:P regimen. Black ducks seemed to display these signs over a wider range of diets than mallards. Diets of 1,000 mg/kg Al had toxic effects on both species, particularly when combined with diets low in Ca and P.

Economic and Environmental Consequences of Widespread Expansion of Solar energy

NASA Astrophysics Data System (ADS)

Satija, Gaurav

The purpose of the thesis is to examine the sustainability of an expansion in solar energy subject to resource constraints of Indium. Coal and natural gas are taken as competitors for solar in the energy market. The consumer electronics market also competes with solar PV production because of Indium's use in the manufacturing of LCD screens. A partial equilibrium model is made which determines the rate of extraction of indium, coal and natural gas endogenously. Consumer demand is modeled by the use of cost shares. Generation of electricity and production of LCDs are modeled using Constant Elasticity of Substitution functions. Initial production capacity for both electricity and LCD is considered in the model. The model then endogenously determines the level of investment required. Model simulations are performed to predict the extraction paths and production levels for a timeline of 100 years. A sensitivity analysis is performed to see the reaction of the model to changes in consumer demand and learning rates in solar energy. The response of the model to imposition of various emission caps is also shown. Results of the model show that indium scarcity prevents solar from expanding significantly to a level where it can take over from non-renewable sources of energy. Increased research in solar technologies would not be of much help unless more Indium is available, either by recycling of solar PVs and LCDs or searching for alternate technologies to manufacture LCD screes. Emission caps are able to control excessive usage of fossil fuels and preserve them for a longer time.

Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific coastal marine stratocumulus during VOCALS-REx

NASA Astrophysics Data System (ADS)

Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

2011-05-01

Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. The BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL on days without predominately synoptic and meso-scale influences. The BL had a depth of 1140 ± 120 m, was well-mixed and capped by a sharp inversion. The wind direction generally switched from southerly within the BL to northerly above the inversion. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. From 29 October to 4 November, when a synoptic system affected conditions at Point Alpha, the cloud LWP was higher than on the other days by around 40 g m-2. On 1 and 2 November, a moist layer above the inversion moved over Point Alpha. The total-water specific humidity above the inversion was larger than that within the BL during these days. Entrainment rates (average of 1.5 ± 0.6 mm s-1) calculated from the near cloud-top fluxes and turbulence (vertical velocity variance) in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3, which was consistent with the satellite-derived values. The relationship of cloud droplet number concentration and CCN at 0.2 % supersaturation from 18 flights is Nd =4.6 × CCN0.71. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft {in situ} observations near cloud top. The aerosol and cloud LWP relationship reveals that during the typical well-mixed BL days the cloud LWP increased with the CCN concentrations. On the other hand, meteorological factors and the decoupling processes have large influences on the cloud LWP variation as well.

The involvement of hypoxia-inducible transcription factor-1-dependent pathway in nickel carcinogenesis.

PubMed

Salnikow, Konstantin; Davidson, Todd; Zhang, Qunwei; Chen, Lung Chi; Su, Weichen; Costa, Max

2003-07-01

Nickel is a potent environmental pollutant in industrial countries. Because nickel compounds are carcinogenic, exposure to nickel represents a serious hazard to human health. The understanding of how nickel exerts its toxic and carcinogenic effects at a molecular level may be important in risk assessment, as well as in the treatment and prevention of occupational diseases. Previously, using human and rodent cells in vitro, we showed that hypoxia-inducible signaling pathway was activated by carcinogenic nickel compounds. Acute exposure to nickel resulted in the accumulation of hypoxia-inducible transcription factor (HIF)-1, which strongly activated hypoxia-inducible genes, including the recently discovered tumor marker NDRG1 (Cap43). To further identify HIF-1-dependent nickel-inducible genes and to understand the role of the HIF-dependent signaling pathway in nickel-induced transformation, we used the Affymetrix GeneChip to compare the gene expression profiles in wild-type cells or in cells from HIF-1 alpha knockout mouse embryos exposed to nickel chloride. As expected, when we examined 12,000 genes for expression changes, we found that genes coding for glycolytic enzymes and glucose transporters, known to be regulated by HIF-1 transcription factor, were induced by nickel only in HIF-1 alpha-proficient cells. In addition, we found a number of other hypoxia-inducible genes up-regulated by nickel in a HIF-dependent manner including BCL-2-binding protein Nip3, EGLN1, hypoxia-inducible gene 1 (HIG1), and prolyl 4-hydroxylase. Additionally, we found a number of genes induced by nickel in a HIF-independent manner, suggesting that Ni activated other signaling pathways besides HIF-1. Finally, we found that in HIF-1 alpha knockout cells, nickel strongly induced the expression of the whole group of genes that were not expressed in the presence of HIF-1. Because the majority of modulated genes were induced or suppressed by nickel in a HIF-1-dependent manner, we elucidated the role of HIF-1 transcription factor in cell transformation. In HIF-1 alpha-proficient cells, nickel exposure increased soft agar growth, whereas it decreased soft agar growth in HIF-1 alpha-deficient cells. We hypothesize that the induction of HIF-1 transcription factor by nickel may be important during the nickel-induced carcinogenic process.

Interfacial behavior of N-nitrosodiethylamine/bovine serum albumin complexes at the air-water and the chloroform-water interfaces by axisymmetric drop tensiometry.

PubMed

Juárez, J; Galaz, J G; Machi, L; Burboa, M; Gutiérrez-Millán, L E; Goycoolea, F M; Valdez, M A

2007-03-15

Interfacial properties of N-nitrosodiethylamine/bovine serum albumin (NDA/BSA) complexes were investigated at the air-water interface. The interfacial behavior at the chloroform-water interface of the interaction product of phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), dissolved in the chloroform phase, and NDA/BSA complex, in the aqueous phase, were also analyzed by using a drop tensiometer. The secondary structure changes of BSA with different NDA concentrations were monitored by circular dichroism spectroscopy at different pH and the NDA/BSA interaction was probed by fluorescence spectroscopy. Different NDA/BSA mixtures were prepared from 0, 7.5 x 10(-5), 2.2 x 10(-4), 3.7 x 10(-4), 5 x 10(-4), 1.6 x 10(-3), and 3.1 x 10(-3) M NDA solutions in order to afford 0, 300/1, 900/1, 1 500/1, 2 000/1, 6 000/1, and 12 500/1 NDA/BSA molar ratios, respectively, in the aqueous solutions. Increments of BSA alpha-helix contents were obtained up to the 2 000/1 NDA/BSA molar ratio, but at ratios beyond this value, the alpha-helix content practically disappeared. These BSA structure changes produced an increment of the surface pressure at the air-water interface, as the alpha-helix content increased with the concentration of NDA. On the contrary, when alpha-helix content decreased, the surface pressure also appeared lower than the one obtained with pure BSA solutions. The interaction of DPPC with NDA/BSA molecules at the chloroform-water interface produced also a small, but measurable, pressure increment with the addition of NDA molecules. Dynamic light scattering measurements of the molecular sizes of NDA/BSA complex at pH 4.6, 7.1, and 8.4 indicated that the size of extended BSA molecules at pH 4.6 increased in a greater proportion with the increment in NDA concentration than at the other studied pH values. Diffusion coefficients calculated from dynamic surface tension values, using a short-term solution of the general adsorption model of Ward and Tordai, also showed differences with pH and the NDA concentration. Both, the storage and loss dilatational elastic modulus were obtained at the air-water and at the chloroform-water interfaces. The interaction of NDA/BSA with DPPC at the chloroform-water produced a less rigid monolayer than the one obtained with pure DPPC (1 x 10(-5) M), indicating a significant penetration of NDA/BSA molecules at the interface. At short times and pH 4.6, the values of the storage elastic modulus were larger and more sensible to the NDA addition than the ones at pH 7.1 and 8.4, probably due to a gel-like network formation at the air-water interface.

42 CFR 414.917 - Dispute resolution and process for suspension or termination of approved CAP contract and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... quality of a CAP drug supplied by the approved CAP vendor to be unsatisfactory, then the physician may address the issue first through the approved CAP vendor's grievance process, and second through an... approved CAP vendor's service or the quality of a CAP drug supplied by the approved CAP vendor, then the...

Child psychiatry: what are we teaching medical students?

PubMed

Dingle, Arden D

2010-01-01

The author describes child and adolescent psychiatry (CAP) undergraduate teaching in American and Canadian medical schools. A survey asking for information on CAP teaching, student interest in CAP, and opinions about the CAP importance was sent to the medical student psychiatry director at 142 accredited medical schools in the United States and Canada. The results were summarized and various factors considered relevant to CAP student interest were analyzed statistically. Approximately 81% of the schools returned surveys. Most teach required CAP didactics in the preclinical and clinical years. Almost 63% of the schools have CAP clinical rotations; most are not required. Twenty-three percent of all medical students have a clinical CAP experience during their psychiatry clerkship. The majority of schools have CAP electives, and approximately 4.8% of students participate. Child and adolescent psychiatry leadership, early exposure to CAP, and CAP clinical experiences were related to student CAP interest, but these relationships were not statistically significant. The time allotted to teaching CAP in the undergraduate medical curriculum is minimal, consistent with previous survey results. Most schools require didactic instruction averaging about 12 hours and offer elective clinical opportunities. The survey findings should help direct future planning to improve CAP medical student education.

Ability of barrier coat S-PRG coating to arrest artificial enamel lesions in primary teeth.

PubMed

Hosoya, Yumiko; Ando, Susumu; Otani, Hideji; Yukinari, Tetsuhiro; Miyazaki, Masashi; Garcia-Godoy, Franklin

2013-10-01

To evaluate the effects of a surface pre-reacted glass-ionomer (S-PRG) filled coating material to arrest artificial enamel lesions in primary teeth. Buccal and lingual enamel was demineralized in 0.1 M lactic acid buffer solution (pH 4.75) for 5 days and then divided in the PRG-applied and non-PRG areas. Proximal surfaces were used as a control area without demineralization and coating application. Teeth were divided into three groups (n = 4) according to the 1-week immersion in different solutions: Group 1 (distilled water), Group 2 (demineralizing solution) and Group 3 (artificial saliva). Hardness and Young's modulus by nano-indentation test, and elemental contents and ultrastructure by SEM/EDX analysis were obtained. Data were statistically analyzed using ANOVA and Fisher's PLSD at alpha = 0.05. Only for the non-PRG area in Group 1, the hardness and Young's modulus of the demineralized surface enamel were significantly lower than those of the enamel 30-60 microm beneath the surface. Demineralized enamel of non-PRG and PRG-applied areas showed similar SEM views. Only for the non-PRG area in Group 2 and control area in Group 3, the Ca/P of the surface enamel was significantly higher than that of the enamel 5-10 microm beneath the surface. There was no significant difference of the Ca/P among the measuring points from the surface to 10 microm depth of enamel for the PRG applied area in Group 2.

Influence of Different Container Closure Systems and Capping Process Parameters on Product Quality and Container Closure Integrity (CCI) in GMP Drug Product Manufacturing.

PubMed

Mathaes, Roman; Mahler, Hanns-Christian; Roggo, Yves; Huwyler, Joerg; Eder, Juergen; Fritsch, Kamila; Posset, Tobias; Mohl, Silke; Streubel, Alexander

2016-01-01

Capping equipment used in good manufacturing practice manufacturing features different designs and a variety of adjustable process parameters. The overall capping result is a complex interplay of the different capping process parameters and is insufficiently described in literature. It remains poorly studied how the different capping equipment designs and capping equipment process parameters (e.g., pre-compression force, capping plate height, turntable rotating speed) contribute to the final residual seal force of a sealed container closure system and its relation to container closure integrity and other drug product quality parameters. Stopper compression measured by computer tomography correlated to residual seal force measurements.In our studies, we used different container closure system configurations from different good manufacturing practice drug product fill & finish facilities to investigate the influence of differences in primary packaging, that is, vial size and rubber stopper design on the capping process and the capped drug product. In addition, we compared two large-scale good manufacturing practice manufacturing capping equipment and different capping equipment settings and their impact on product quality and integrity, as determined by residual seal force.The capping plate to plunger distance had a major influence on the obtained residual seal force values of a sealed vial, whereas the capping pre-compression force and the turntable rotation speed showed only a minor influence on the residual seal force of a sealed vial. Capping process parameters could not easily be transferred from capping equipment of different manufacturers. However, the residual seal force tester did provide a valuable tool to compare capping performance of different capping equipment. No vial showed any leakage greater than 10(-8)mbar L/s as measured by a helium mass spectrometry system, suggesting that container closure integrity was warranted in the residual seal force range tested for the tested container closure systems. Capping equipment used in good manufacturing practice manufacturing features different designs and a variety of adjustable process parameters. The overall capping result is a complex interplay of the different capping process parameters and is insufficiently described in the literature. It remains poorly studied how the different capping equipment designs and capping equipment process parameters contribute to the final capping result.In this study, we used different container closure system configurations from different good manufacturing process drug product fill & finish facilities to investigate the influence of the vial size and the rubber stopper design on the capping process. In addition, we compared two examples of large-scale good manufacturing process capping equipment and different capping equipment settings and their impact on product quality and integrity, as determined by residual seal force. © PDA, Inc. 2016.

Calcination does not remove all carbon from colloidal nanocrystal assemblies

DOE PAGES

Mohapatra, Pratyasha; Shaw, Santosh; Mendivelso-Perez, Deyny; ...

2017-12-11

Removing organics from hybrid nanostructures is a crucial step in many bottom-up materials fabrication approaches. It is usually assumed that calcination is an effective solution to this problem, especially for thin films. This assumption has led to its application in thousands of papers. Here in this paper, we show that this general assumption is incorrect by using a relevant and highly controlled model system consisting of thin films of ligand-capped ZrO 2 nanocrystals. After calcination at 800 °C for 12 h, while Raman spectroscopy fails to detect the ligands after calcination, elastic backscattering spectrometry characterization demonstrates that ~18% of themore » original carbon atoms are still present in the film. By comparison plasma processing successfully removes the ligands. Our growth kinetic analysis shows that the calcined materials have significantly different interfacial properties than the plasma-processed counterparts. Calcination is not a reliable strategy for the production of single-phase all-inorganic materials from colloidal nanoparticles.« less

Reference pricing with endogenous generic entry.

PubMed

Brekke, Kurt R; Canta, Chiara; Straume, Odd Rune

2016-12-01

Reference pricing intends to reduce pharmaceutical expenditures by increasing demand elasticity and stimulating generic competition. We develop a novel model where a brand-name producer competes in prices with several generics producers in a market with brand-biased and brand-neutral consumers. Comparing with coinsurance, we show that reference pricing, contrary to policy makers' intentions, discourages generic entry, as it induces the brand-name producer to price more aggressively. Thus, the net effect of reference pricing on drug prices is ambiguous, implying that reference pricing can be counterproductive in reducing expenditures. However, under price regulation, we show that reference pricing may stimulate generic entry, since a binding price cap weakens the aggressive price response by the brand-name producer. This may explain mixed empirical results on the competitive effects of reference pricing. Finally, we show that reference pricing may be welfare improving when accounting for brand preferences despite its adverse effects on entry and prices. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of low-dose doxorubicin-loaded silica-based nanocomposites

NASA Astrophysics Data System (ADS)

Prokopowicz, Magdalena

2018-01-01

In this study, we synthesized multicomponent solid films of low-dose doxorubicin (DOX)-loaded polydimethylsiloxane (PDMS)-SiO2/CaP nanocomposites via sol-gel process combined with the method of evaporation-induced self-assembly (EISA) at low temperature. Nanomechanical properties (elasticity and adhesion) of the synthesized multicomponent films were determined by using atomic force microscopy with a PeakForce™ quantitative nanomechanical mapping imaging technique. Solid state of DOX in the synthesized films was studied by using UV-vis and fluorescence spectroscopy. The release profile of different concentrations of DOX loaded (1, 3, and 5 wt%) on the multicomponent films was assessed using USP Apparatus 4 and via UV-vis end analysis. Results indicate drug-component interactions on the overall morphology of domains (size and shape), nanomechanical properties, and release behavior of the DOX-loaded nanocomposites. We observed a progressive increase in surface roughness and mean adhesive value with increasing concentration of DOX loaded (0-5 wt%). In addition, for all the different concentrations of DOX-loaded, we observed a diffusion-controlled drug release.

Mechanics of Lamellipodia

NASA Astrophysics Data System (ADS)

Quint, D. A.; Schwarz, J. M.

2008-03-01

The actin cytoskeleton is a morphologically-complex assembly of cross-linked F-actin filaments. The cytoskeleton provides rigidity for the cell within appropriate time scales so that it can change its shape to, for example, crawl along surfaces. In addition to cross-linking proteins, many other proteins are involved in the assembly of the actin cytoskeleton such as branching proteins, capping proteins, and severing proteins. Presumably these proteins work cooperatively toward the dynamic formation of rigidity. We will initially focus on the role of branching proteins. The F-actin filaments in lamellipodia---protrusions of the mobile edge of a crawling cell---have some overall orientation due to the branching. Branched filaments emerge at a 70 degree angle from the mother filament's growing end.^1 This overall orientation is modelled as an anisotropy in an effective medium theory determining the cytoskeleton's elasticity in the static regime. The potential for a splay rigid phase, in addition to a rigid phase, is also investigated. ^1T. M. Svitkina and G. G. Borisy, J. Cell Biol. 145, 1009 (1999).

Development of a flameproof elastic elastomeric fiber

NASA Technical Reports Server (NTRS)

Howarth, J. T.; Nilgrom, J.; Massucco, A.; Sheth, S. G.; Dawn, F. S.

1971-01-01

Various flexible polyurethane structures containing halogen were synthesized from polyesters derived from aliphatic or aromatic polyols and dibasic acids. Aliphatic halide structures could not be used because they are unstable at the required reaction temperatures, giving of hydrogen halide which hydrolyzes the ester linkages. In contract, halogen-containing aromatic polyols were stable and satisfactory products were made. The most promising composition, a brominated neopentyl glycol capped with toluene disocyanate, was used as a conventional diisocyanate, in conjunction with hydroxy-terminated polyethers or polyesters to form elastomeric urethanes containing about 10% bromine with weight. Products made in this manner will not burn in air, have an oxygen index value of about 25, and have tensile strength values of about 5,000 psi at 450% elongation. The most efficient additives for imparting flame retardancy to Spandex urethanes are aromatic halides and the most effective of these are the bromide compounds. Various levels of flame retardancy have been achieved depending on the levels of additives used.

Effect of stiffness characteristics on the response of composite grid-stiffened structures

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Rehfield, Lawrence W.

1991-01-01

A study of the effect of stiffness discontinuities and structural parameters on the response of continuous-filament grid-stiffened flat panels is presented. The buckling load degradation due to manufacturing-introduced stiffener discontinuities associated with a filament cut-and-add approach at the stiffener intersections is investigated. The degradation of buckling resistance in isogrid flat panels subjected to uni-axial compression and combined axial compression and shear loading conditions and induced damage is quantified using FEM. The combined loading case is the most critical one. Nonsolid stiffener cross sections, such as a foam-filled blade or hat with a 0-deg dominant cap, result in grid-stiffened structures that are structurally very efficient for wing and fuselage applications. The results of a study of the ability of grid-stiffened structural concepts to enhance the effective Poisson's ratio of a panel are presented. Grid-stiffened concepts create a highly effective Poisson's ratio, which can produce large camber deformations for certain elastic tailoring applications.

Multi-Center, Double-Blind, Vehicle-Controlled Clinical Trial of an Alpha and Beta Defensin-Containing Anti-Aging Skin Care Regimen With Clinical, Histopathologic, Immunohistochemical, Photographic, and Ultrasound Evaluation.

PubMed

Taub, Amy; Bucay, Vivian; Keller, Gregory; Williams, Jay; Mehregan, Darius

2018-04-01

Anti-aging strategies utilizing stem cells are in the forefront. Alpha and beta defensins are natural immune peptides that have been shown to activate an LGR6-positive stem cell locus in the hair follicle, identified as the source of most new epidermal cells during acute wound healing. We investigated the ability of biomimetic alpha and beta defensin molecules, supplemented with supportive cosmetic ingredients, formulated into three skin care products, at improving the structure and function of aging skin. A participant- and investigator -blinded, placebo-controlled, multi-center trial was performed in outpatient settings. Forty-four healthy female subjects, aged 41-71 years, skin types I-V, completed the study with 2/3 receiving full formula and 1/3 receiving the placebo formula. A skin care regimen of 3 products (serum, cream, and mask) containing alpha-defensin 5 and beta-defensin 3, and other cosmetic ingredients, was applied to the face, post-auricular, and neck skin two times per day for 12 weeks in those receiving full formula, whereas the placebo group received the identically packaged regimen without the active ingredients. Methods of evaluation included histopathology and immunohistochemistry (7 subjects), clinical evaluation of pores, superficial and deep wrinkles based on Griffiths scale, and high-resolution photography (all subjects). In addition, a subset of 15 patients were evaluated with the QuantifiCare system (3-dimensional imaging and skin care scores for evenness, pores, oiliness) and Cortex measurements (high-resolution skin ultrasound, TEWL, elasticity, color, and hydration). Data points for evaluation included baseline, 6 weeks, and 12 weeks. All patients used the same sunscreen and cleanser, which was provided to them. The full formula regimen caused a significantly (P equals 0.027) increased thickness of the epidermis as seen in histology, not seen in the placebo group, with no signs of inflammation. No excessive cell proliferation was detected in either group as measured by Ki67-immunohistochemistry. Reduction in visible pores, superficial wrinkles, oiliness, pigmentation, and improvement of skin evenness, were statistically significant. A trend for improvement was also observed in skin elasticity, TEWL, and hydration; these did not achieve statistical significance. Ultrasound and histopathology demonstrated increases in dermal thickness in individual patients, without statistical significance. Comprehensive improvement in all 5 parameters, including visible pores, hyperpigmentation, superficial and deep wrinkles, and epidermal thickness, was statistically significant when the subset of participants assigned for histology in full formula group was compared with the placebo group participants. A 3-product skin care regimen containing alpha and beta defensins globally improves the visual appearance and structure of aging skin without irritation, dryness, or inflammation. Specifically, this regimen increases epidermal thickness, reduces appearance of pores, reduces wrinkles, and reduces melanin. This skin care regimen stimulates rejuvenation without evidence of increase of a marker of carcinogenic stimulation. This data is consistent with the hypothesis that a defensin-containing skin care regimen activates the body's own dormant stem cells to generate healthy new epidermal cells.

J Drugs Dermatol. 2018;17(4):426-441.

High strength, biodegradable and cytocompatible alpha tricalcium phosphate-iron composites for temporal reduction of bone fractures.

PubMed

Montufar, E B; Casas-Luna, M; Horynová, M; Tkachenko, S; Fohlerová, Z; Diaz-de-la-Torre, S; Dvořák, K; Čelko, L; Kaiser, J

2018-04-01

In this work alpha tricalcium phosphate (α-TCP)/iron (Fe) composites were developed as a new family of biodegradable, load-bearing and cytocompatible materials. The composites with composition from pure ceramic to pure metallic samples were consolidated by pulsed electric current assisted sintering to minimise processing time and temperature while improving their mechanical performance. The mechanical strength of the composites was increased and controlled with the Fe content, passing from brittle to ductile failure. In particular, the addition of 25 vol% of Fe produced a ceramic matrix composite with elastic modulus much closer to cortical bone than that of titanium or biodegradable magnesium alloys and specific compressive strength above that of stainless steel, chromium-cobalt alloys and pure titanium, currently used in clinic for internal fracture fixation. All the composites studied exhibited higher degradation rate than their individual components, presenting values around 200 μm/year, but also their compressive strength did not show a significant reduction in the period required for bone fracture consolidation. Composites showed preferential degradation of α-TCP areas rather than β-TCP areas, suggesting that α-TCP can produce composites with higher degradation rate. The composites were cytocompatible both in indirect and direct contact with bone cells. Osteoblast-like cells attached and spread on the surface of the composites, presenting proliferation rate similar to cells on tissue culture-grade polystyrene and they showed alkaline phosphatase activity. Therefore, this new family of composites is a potential alternative to produce implants for temporal reduction of bone fractures. Biodegradable alpha-tricalcium phosphate/iron (α-TCP/Fe) composites are promising candidates for the fabrication of temporal osteosynthesis devices. Similar to biodegradable metals, these composites can avoid implant removal after bone fracture healing, particularly in young patients. In this work, α-TCP/Fe composites are studied for the first time in a wide range of compositions, showing not only higher degradation rate in vitro than pure components, but also good cytocompatibility and mechanical properties controllable with the Fe content. Ceramic matrix composites show high specific strength and low elastic modulus, thus better fulfilling the requirements for bone fractures fixation. A significant advance over previous works on the topic is the use of pulsed electric current assisted sintering together with α-TCP, convenient to improve the mechanical performance and degradation rate, respectively. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A large-scale field trial of thin-layer capping of PCDD/F-contaminated sediments: Sediment-to-water fluxes up to 5 years post-amendment.

PubMed

Cornelissen, Gerard; Schaanning, Morten; Gunnarsson, Jonas S; Eek, Espen

2016-04-01

The longer-term effect (3-5 y) of thin-layer capping on in situ sediment-to-surface water fluxes was monitored in a large-scale field experiment in the polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) contaminated Grenlandfjords, Norway (4 trial plots of 10,000 to 40,000 m(2) at 30 to 100 m water depth). Active caps (designed thickness 2.5 cm) were established in 2 fjords, consisting of dredged clean clay amended with powdered activated carbon (PAC) from anthracite. These active caps were compared to 2 nonactive caps in one of the fjords (designed thickness 5 cm) consisting of either clay only (i.e., without PAC) or crushed limestone. Sediment-to-water PCDD/F fluxes were measured in situ using diffusion chambers. An earlier study showed that during the first 2 years after thin-layer capping, flux reductions relative to noncapped reference fields were more extensive at the fields capped with nonactive caps (70%-90%) than at the ones with PAC-containing caps (50%-60%). However, the present work shows that between 3 and 5 years after thin-layer capping, this trend was reversed and cap effectiveness in reducing fluxes was increasing to 80% to 90% for the PAC caps, whereas cap effectiveness of the nonactive caps decreased to 20% to 60%. The increasing effectiveness over time of PAC-containing "active" caps is explained by a combination of slow sediment-to-PAC mass transfer of PCDD/Fs and bioturbation by benthic organisms. The decreasing effectiveness of "nonactive" limestone and clay caps is explained by deposition of contaminated particles on top of the caps. The present field data indicate that the capping efficiency of thin active caps (i.e., enriched with PAC) can improve over time as a result of slow diffusive PCDD/F transfer from sediment to PAC particles and better mixing of the PAC by bioturbation. © 2015 SETAC.

Impact of out-of-pocket spending caps on financial burden of those with group health insurance.

PubMed

Riggs, Kevin R; Buttorff, Christine; Alexander, G Caleb

2015-05-01

The Affordable Care Act (ACA) mandates that all private health insurance include out-of-pocket spending caps. Insurance purchased through the ACA's Health Insurance Marketplace may qualify for income-based caps, whereas group insurance will not have income-based caps. Little is known about how out-of-pocket caps impact individuals' health care financial burden. We aimed to estimate what proportion of non-elderly individuals with group insurance will benefit from out-of-pocket caps, and the effect that various cap levels would have on their financial burden. We applied the expected uniform spending caps, hypothetical reduced uniform spending caps (reduced by one-third), and hypothetical income-based spending caps (similar to the caps on Health Insurance Marketplace plans) to nationally representative data from the Medical Expenditure Panel Survey (MEPS). Participants were non-elderly individuals (aged < 65 years) with private group health insurance in the 2011 and 2012 MEPS surveys (n =26,666). (1) The percentage of individuals with reduced family out-of-pocket spending as a result of the various caps; and (2) the percentage of individuals experiencing health care services financial burden (family out-of-pocket spending on health care, not including premiums, greater than 10% of total family income) under each scenario. With the uniform caps, 1.2% of individuals had lower out-of-pocket spending, compared with 3.8% with reduced uniform caps and 2.1% with income-based caps. Uniform caps led to a small reduction in percentage of individuals experiencing financial burden (from 3.3% to 3.1%), with a modestly larger reduction as a result of reduced uniform caps (2.9%) and income-based caps (2.8%). Mandated uniform out-of-pocket caps for those with group insurance will benefit very few individuals, and will not result in substantial reductions in financial burden.

Structure of a two-CAP-domain protein from the human hookworm parasite Necator americanus

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

Asojo, Oluwatoyin A., E-mail: oasojo@unmc.edu

2011-05-01

The first structure of a two-CAP-domain protein, Na-ASP-1, from the major human hookworm parasite N. americanus refined to a resolution limit of 2.2 Å is presented. Major proteins secreted by the infective larval stage hookworms upon host entry include Ancylostoma secreted proteins (ASPs), which are characterized by one or two CAP (cysteine-rich secretory protein/antigen 5/pathogenesis related-1) domains. The CAP domain has been reported in diverse phylogenetically unrelated proteins, but has no confirmed function. The first structure of a two-CAP-domain protein, Na-ASP-1, from the major human hookworm parasite Necator americanus was refined to a resolution limit of 2.2 Å. The structuremore » was solved by molecular replacement (MR) using Na-ASP-2, a one-CAP-domain ASP, as the search model. The correct MR solution could only be obtained by truncating the polyalanine model of Na-ASP-2 and removing several loops. The structure reveals two CAP domains linked by an extended loop. Overall, the carboxyl-terminal CAP domain is more similar to Na-ASP-2 than to the amino-terminal CAP domain. A large central cavity extends from the amino-terminal CAP domain to the carboxyl-terminal CAP domain, encompassing the putative CAP-binding cavity. The putative CAP-binding cavity is a characteristic cavity in the carboxyl-terminal CAP domain that contains a His and Glu pair. These residues are conserved in all single-CAP-domain proteins, but are absent in the amino-terminal CAP domain. The conserved His residues are oriented such that they appear to be capable of directly coordinating a zinc ion as observed for CAP proteins from reptile venoms. This first structure of a two-CAP-domain ASP can serve as a template for homology modeling of other two-CAP-domain proteins.« less

A comparative study of internally and externally capped balloons using small scale test balloons

NASA Technical Reports Server (NTRS)

Bell, Douglas P.

1994-01-01

Caps have been used to structurally reinforce scientific research balloons since the late 1950's. The scientific research balloons used by the National Aeronautics and Space Administration (NASA) use internal caps. A NASA cap placement specification does not exist since no empirical information exisits concerning cap placement. To develop a cap placement specification, NASA has completed two in-hangar inflation tests comparing the structural contributions of internal caps and external caps. The tests used small scale test balloons designed to develop the highest possible stresses within the constraints of the hangar and balloon materials. An externally capped test balloon and an internally capped test balloon were designed, built, inflated and simulated to determine the structural contributions and benefits of each. The results of the tests and simulations are presented.

Novel 3D-printing technique for caps to enable tailored therapeutic endoscopy.

PubMed

Ko, Weon Jin; Song, Ga Won; Hong, Sung Pyo; Kwon, Chang-il; Hahm, Ki Baik; Cho, Joo Young

2016-03-01

To evaluate the feasibility of a tailored endoscopic cap created using 3D-printing technology that is customized according to esophagogastric lesions of each patient. Tailored endoscopic caps, which were designed and fabricated with a 3D printer, were inserted in 35 patients. The types of cap were side-hole cap made for cap-assisted endoscopic mucosal resection (EMRC), oblique-head cap designed for endoscopic submucosal dissection (ESD), wide-head cap used for Trucut biopsy (TCB), and narrow-tip cap to facilitate peroral endoscopic myotomy (POEM). EMRC in the esophagus and gastroesophageal junction was carried out using a side-hole cap in seven patients. Median total procedure time for successful removal of lesions was 14 min (range 8-50 min). Gastric ESD was carried out using with an oblique-head cap in 16 patients, for which the median total procedure time was 53 min. TCB in the esophagus was done using a wide-head cap in eight patients. While carrying out POEM for tunneling, a narrow-tip cap was used in four patients with achalasia. Based on the current proof-of-concept study, we anticipate that creating a tailored endoscopic cap is feasible for therapeutic endoscopy. © 2015 Japan Gastroenterological Endoscopy Society.

Incorporating spatial constraint in co-activation pattern analysis to explore the dynamics of resting-state networks: An application to Parkinson's disease.

PubMed

Zhuang, Xiaowei; Walsh, Ryan R; Sreenivasan, Karthik; Yang, Zhengshi; Mishra, Virendra; Cordes, Dietmar

2018-05-15

The dynamics of the brain's intrinsic networks have been recently studied using co-activation pattern (CAP) analysis. The CAP method relies on few model assumptions and CAP-based measurements provide quantitative information of network temporal dynamics. One limitation of existing CAP-related methods is that the computed CAPs share considerable spatial overlap that may or may not be functionally distinct relative to specific network dynamics. To more accurately describe network dynamics with spatially distinct CAPs, and to compare network dynamics between different populations, a novel data-driven CAP group analysis method is proposed in this study. In the proposed method, a dominant-CAP (d-CAP) set is synthesized across CAPs from multiple clustering runs for each group with the constraint of low spatial similarities among d-CAPs. Alternating d-CAPs with less overlapping spatial patterns can better capture overall network dynamics. The number of d-CAPs, the temporal fraction and spatial consistency of each d-CAP, and the subject-specific switching probability among all d-CAPs are then calculated for each group and used to compare network dynamics between groups. The spatial dissimilarities among d-CAPs computed with the proposed method were first demonstrated using simulated data. High consistency between simulated ground-truth and computed d-CAPs was achieved, and detailed comparisons between the proposed method and existing CAP-based methods were conducted using simulated data. In an effort to physiologically validate the proposed technique and investigate network dynamics in a relevant brain network disorder, the proposed method was then applied to data from the Parkinson's Progression Markers Initiative (PPMI) database to compare the network dynamics in Parkinson's disease (PD) and normal control (NC) groups. Fewer d-CAPs, skewed distribution of temporal fractions of d-CAPs, and reduced switching probabilities among final d-CAPs were found in most networks in the PD group, as compared to the NC group. Furthermore, an overall negative association between switching probability among d-CAPs and disease severity was observed in most networks in the PD group as well. These results expand upon previous findings from in vivo electrophysiological recording studies in PD. Importantly, this novel analysis also demonstrates that changes in network dynamics can be measured using resting-state fMRI data from subjects with early stage PD. Copyright © 2018 Elsevier Inc. All rights reserved.

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

Sunil, Vasanthi R., E-mail: sunilvr@eohsi.rutgers.edu; Patel-Vayas, Kinal, E-mail: kinalv5@gmail.com; Shen, Jianliang, E-mail: jianliangs@gmail.com

Lung toxicity induced by sulfur mustard is associated with inflammation and oxidative stress. To elucidate mechanisms mediating pulmonary damage, we used 2-chloroethyl ethyl sulfide (CEES), a model sulfur mustard vesicant. Male mice (B6129) were treated intratracheally with CEES (3 or 6 mg/kg) or control. Animals were sacrificed 3, 7 or 14 days later and bronchoalveolar lavage (BAL) fluid and lung tissue collected. Treatment of mice with CEES resulted in an increase in BAL protein, an indication of alveolar epithelial damage, within 3 days. Expression of Ym1, an oxidative stress marker also increased in the lung, along with inducible nitric oxidemore » synthase, and at 14 days, cyclooxygenase-2 and monocyte chemotactic protein-1, inflammatory proteins implicated in tissue injury. These responses were attenuated in mice lacking the p55 receptor for TNF{alpha} (TNFR1-/-), demonstrating that signaling via TNFR1 is key to CEES-induced injury, oxidative stress, and inflammation. CEES-induced upregulation of CuZn-superoxide dismutase (SOD) and MnSOD was delayed or absent in TNFR1-/- mice, relative to WT mice, suggesting that TNF{alpha} mediates early antioxidant responses to lung toxicants. Treatment of WT mice with CEES also resulted in functional alterations in the lung including decreases in compliance and increases in elastance. Additionally, methacholine-induced alterations in total lung resistance and central airway resistance were dampened by CEES. Loss of TNFR1 resulted in blunted functional responses to CEES. These effects were most notable in the airways. These data suggest that targeting TNF{alpha} signaling may be useful in mitigating lung injury, inflammation and functional alterations induced by vesicants.« less

Stress analysis in patella by three-dimensional photoelasticity

NASA Astrophysics Data System (ADS)

Chen, Riqi; Zhang, Jianxing; Jiang, Kunsheng

1991-12-01

In this paper, stress distribution in patella was studied by 3-D photoelastic experiments and finite element calculations. The experimental conditions were in good agreement with that of body mechanics: (1) The ratios of m. quadriceps femoris force FQ to lig. patella force FP were 1.03 - 1.42. (2) The angles between FQ and FP were 8.4 degree(s) - 18.7 degree(s). (3) The ratio of modulus of elasticity for epoxy resin and silicon rubber matched that for patella and cartilage, i.e., 145:1. The principal stresses and their path line, normal stresses, and contact stresses between patella and ossis femoris were determined in various flexion angles (15 degree(s), 30 degree(s), 45 degree(s), 60 degree(s), 75 degree(s), 90 degree(s)). Two of the correlations were: (1) Maximum principal stress in the front of patella; (sigma) max equals 35.8Wexp(0.024(alpha) ) KPa. (2) Maximum contact stress between patella and ossis femoris; (sigma) max equals -(6.86 - 0.14(alpha) + 0.02(alpha) 2)W KPa where W was body weight subjected by a single foot. It was proved that the transverse break of patella resulted from the case that the principle stress in the front of patella exceeded ultimate tensile strength. And Tension Band Wiring (TBW) therapy conformed to the law of physiological stress field. A modified K-needles position in TBW therapy was suggested. These results are useful for further research of human patella mechanics and recovery therapy. No similar result has been found in American MEDLIN Data Bank.

Investigation of the Microstructure and Mechanical Properties of Copper-Graphite Composites Reinforced with Single-Crystal α-Al₂O₃ Fibres by Hot Isostatic Pressing.

PubMed

Zhang, Guihang; Jiang, Xiaosong; Qiao, ChangJun; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao; Valcarcel, Victor

2018-06-11

Single-crystal α-Al₂O₃ fibres can be utilized as a novel reinforcement in high-temperature composites owing to their high elastic modulus, chemical and thermal stability. Unlike non-oxide fibres and polycrystalline alumina fibres, high-temperature oxidation and polycrystalline particles boundary growth will not occur for single-crystal α-Al₂O₃ fibres. In this work, single-crystal α-Al₂O₃ whiskers and Al₂O₃ particles synergistic reinforced copper-graphite composites were fabricated by mechanical alloying and hot isostatic pressing techniques. The phase compositions, microstructures, and fracture morphologies of the composites were investigated using X-ray diffraction, a scanning electron microscope equipped with an X-ray energy-dispersive spectrometer (EDS), an electron probe microscopic analysis equipped with wavelength-dispersive spectrometer, and a transmission electron microscope equipped with EDS. The mechanical properties have been measured by a micro-hardness tester and electronic universal testing machine. The results show that the reinforcements were unevenly distributed in the matrix with the increase of their content and there were some micro-cracks located at the interface between the reinforcement and the matrix. With the increase of the Al₂O₃ whisker content, the compressive strength of the composites first increased and then decreased, while the hardness decreased. The fracture and strengthening mechanisms of the composite materials were explored on the basis of the structure and composition of the composites through the formation and function of the interface. The main strengthening mechanism in the composites was fine grain strengthening and solid solution strengthening. The fracture type of the composites was brittle fracture.

Actin protofilament orientation in deformation of the erythrocyte membrane skeleton.

PubMed Central

Picart, C; Dalhaimer, P; Discher, D E

2000-01-01

The red cell's spectrin-actin network is known to sustain local states of shear, dilation, and condensation, and yet the short actin filaments are found to maintain membrane-tangent and near-random azimuthal orientations. When calibrated with polarization results for single actin filaments, imaging of micropipette-deformed red cell ghosts has allowed an assessment of actin orientations and possible reorientations in the network. At the hemispherical cap of the aspirated projection, where the network can be dilated severalfold, filaments have the same membrane-tangent orientation as on a relatively unstrained portion of membrane. Likewise, over the length of the network projection pulled into the micropipette, where the network is strongly sheared in axial extension and circumferential contraction, actin maintains its tangent orientation and is only very weakly aligned with network extension. Similar results are found for the integral membrane protein Band 3. Allowing for thermal fluctuations, we deduce a bound for the effective coupling constant, alpha, between network shear and azimuthal orientation of the protofilament. The finding that alpha must be about an order of magnitude or more below its tight-coupling value illustrates how nanostructural kinematics can decouple from more macroscopic responses. Monte Carlo simulations of spectrin-actin networks at approximately 10-nm resolution further support this conclusion and substantiate an image of protofilaments as elements of a high-temperature spin glass. PMID:11106606

Proposed Trace Gas Measurements Over the Western United States for TROPOMI Validation

NASA Technical Reports Server (NTRS)

Parworth, Caroline L.; Marrero, Josette E.; Yates, Emma L.; Ryoo, Ju-Mee; Iraci, Laura T.

2018-01-01

The Alpha Jet Atmospheric eXperiment (AJAX), located in the Bay Area of California, is a joint effort between NASA Ames Research Center and H211, LCC. AJAX makes in-situ airborne measurements of trace gases 2-4 times per month, resulting in over 216 flights since 2011. Current measurements include ozone (O3), carbon dioxide (CO2), methane (CH4), water (H2O), formaldehyde (HCHO), and meteorological measurements (i.e., ambient pressure, temperature, and 3D winds). Currently, the AJAX team is working to incorporate nitrogen dioxide (NO2) measurements with a Cavity Attenuated Phase Shift Spectrometer (CAPS). Successful science flights coincident with satellite overpasses have been performed since 2011 by the Alpha Jet, with more than 40 flights under the Greenhouse Observing SATellite (GOSAT) and several flights under the Orbiting Carbon Observatory-2 (OCO-2). Results from these flights, which have covered a range of different surfaces and seasonal conditions, will be presented. In-situ vertical profiles of O3, CO2, CH4, H2O, HCHO, and NO2 from the surface to 28,000 feet made by AJAX will also be valuable for satellite validation of data products obtained from the TROPOspheric Montoring Instrument (TROPOMI). TROPOMI is on board the Copernicus Sentinel-5 precursor (S5p) satellite, with level 2 products including O3, CO, CH4, HCHO, NO2, and aerosols.

Mono-PEGylation of Alpha-MMC and MAP30 from Momordica charantia L.: Production, Identification and Anti-Tumor Activity.

PubMed

Sun, Yun; Sun, Fenghui; Li, Jianlong; Wu, Minlu; Fan, Xiang; Meng, Yanfa; Meng, Yao

2016-10-31

PEGylation is a well-established and effective strategy to decrease immunogenicity, which can increase the stability and in vivo half-life time. However, the generation of multi-site modified products is inevitable due to the lysine chemistry, which will bring difficulties in subsequent research, such as purification and quantification. Site-specific modification by mPEG-succinimidyl carbonate (mPEG-SC) is a widely used method for N -terminal conjugation. In this study, we used it for site-directed modification on two ribosome-inactivating proteins (RIPs), alpha-momorcharin (α-MMC) and momordica anti-HIV protein (MAP30), from Momordica charantia L. According to the optimization of previous modification conditions, we compared Macro-Cap SP with SP-Sepharose FF chromatography for separating the final mPEGylated RIPs. Two kinds of methods both can obtain homogenous mPEGylated RIPs which were identified by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing electrophoresis (IEF), and matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) analysis. We also used iodine staining method to detect the amount of unmodified PEG. Furthermore, the inhibition activity of both mPEGylated and non-PEGylated RIPs against human lung adenocarcinoma epithelial A549 cells was detected. All of the results suggested that the mPEGylated α-MMC/MAP30 might be potentially developed as new anti-tumor drugs.

Crystal Structure of MpPR-1i, a SCP/TAPS protein from Moniliophthora perniciosa, the fungus that causes Witches’ Broom Disease of Cacao

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

Baroni, Renata M.; Luo, Zhipu; Darwiche, Rabih

The pathogenic fungi Moniliophthora perniciosa causes Witches’ Broom Disease (WBD) of cacao. The structure of MpPR-1i, a protein expressed by M. perniciosa when it infects cacao, are presented. This is the first reported de novo structure determined by single-wavelength anomalous dispersion phasing upon soaking with selenourea. Each monomer has flexible loop regions linking the core alpha-beta-alpha sandwich topology that comprise ~50% of the structure, making it difficult to generate an accurate homology model of the protein. MpPR-1i is monomeric in solution but is packed as a high ~70% solvent content, crystallographic heptamer. The greatest conformational flexibility between monomers is foundmore » in loops exposed to the solvent channel that connect the two longest strands. MpPR-1i lacks the conserved CAP tetrad and is incapable of binding divalent cations. MpPR-1i has the ability to bind lipids, which may have roles in its infection of cacao. These lipids likely bind in the palmitate binding cavity as observed in tablysin-15, since MpPR-1i binds palmitate with comparable affinity as tablysin-15. Further studies are required to clarify the possible roles and underlying mechanisms of neutral lipid binding, as well as their effects on the pathogenesis of M. perniciosa so as to develop new interventions for WBD.« less

Prediction of allosteric sites on protein surfaces with an elastic-network-model-based thermodynamic method.

PubMed

Su, Ji Guo; Qi, Li Sheng; Li, Chun Hua; Zhu, Yan Ying; Du, Hui Jing; Hou, Yan Xue; Hao, Rui; Wang, Ji Hua

2014-08-01

Allostery is a rapid and efficient way in many biological processes to regulate protein functions, where binding of an effector at the allosteric site alters the activity and function at a distant active site. Allosteric regulation of protein biological functions provides a promising strategy for novel drug design. However, how to effectively identify the allosteric sites remains one of the major challenges for allosteric drug design. In the present work, a thermodynamic method based on the elastic network model was proposed to predict the allosteric sites on the protein surface. In our method, the thermodynamic coupling between the allosteric and active sites was considered, and then the allosteric sites were identified as those where the binding of an effector molecule induces a large change in the binding free energy of the protein with its ligand. Using the proposed method, two proteins, i.e., the 70 kD heat shock protein (Hsp70) and GluA2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, were studied and the allosteric sites on the protein surface were successfully identified. The predicted results are consistent with the available experimental data, which indicates that our method is a simple yet effective approach for the identification of allosteric sites on proteins.