Extended self-similarity works for the Burgers equation and why

Extended self-similarity (ESS), a procedure that remarkably extends the range of scaling for structure functions in Navier-Stokes turbulence and thus allows improved determination of intermittency exponents, has never been fully explained. We show that ESS applies to Burgers turbulence at high Reynolds numbers and we give the theoretical explanation of the numerically observed improved scaling at both the IR and UV end, in total a gain of about three quarters of a decade: there is a reduction of subdominant contributions to scaling when going from the standard structure function representation to the ESS representation. We conjecture that a similar situation holds for three-dimensional incompressible turbulence and suggest ways of capturing subdominant contributions to scaling.

Instability of the self-similar flow into a cavity

In this paper we have investigated the instability of the self-similar flow behind the boundary of a collapsing cavity. The similarity solutions for the flow into a cavity in a fluid obeying a gas law p = Kργ, K = constant and 7 ≥ γ > 1 has been solved by Hunter, who finds that for the same value of γ there are two self-similar flows, one with accelerating cavity boundary and other with constant velocity cavity boundary. We find here that the first of these two flows is unstable. We arrive at this result only by studying the propagation of disturbances in the neighbourhood of the singular point.

Studies on the enzyme hydrolysing flavin mononucleotide in plants: I. Partial purification and properties of the enzyme from Phaseolus radiatus

The partial purification of the enzyme hydrolysing FMN from extracts of greengram seeds (Phaseolus radiatus) is described. The procedures, which entailed precipitation of inert material by manganous sulfate and protamine sulfate treatment, fractional precipitation with alcohol and chromatography on CM-cellulose, afforded preparations whose specific activity was 200 times that of the initial crude extract. The preparation was comparatively specific for FMN. It also hydrolysed, to a much smaller extent, β-glycerophosphate, p-nitrophenyl phosphate and 5′-nucleotides. The differential effects of ions on the FMN and β-glycerophosphate hydrolysing activities are discussed.

Studies on the enzyme hydrolysing flavin mononucleotide in plants. I. Partial purification and properties of the enzyme from Phaseolus radiatus

The partial purification of the enzyme hydrolysing FMN from extracts of greengram seeds (Phaseolus radiatus) is described. The procedures, which entailed precipitation of inert material by manganous sulfate and protamine sulfate treatment, fractional precipitation with alcohol and chromatography on CM-cellulose, afforded preparations whose specific activity was 200 times that of the initial crude extract. The preparation was comparatively specific for FMN. It also hydrolysed, to a much smaller extent, β-glycerophosphate, p-nitrophenyl phosphate and 5′-nucleotides. The differential effects of ions on the FMN and β-glycerophosphate hydrolysing activities are discussed.

On self-interacting oligoribonucleotides. I. Absorption and optical rotatory dispersion of 2′-5′- and 3′-5′-oligoguanylic acids

A series of 2′-5′-oligoguanylic acids are prepared by reacting G(cyclic)p with takadiastase T1 ribonuclease and separating the products chromatographically. The 3′-5′-oligoguanylic acids are obtained by separating the products of alkaline degradation of 3′-5′-poly(G). The optical rotatory dispersion and hypochromism of both 2′-5′- and 3′-5′-oligoguanylic acids are studied at two different pH. The optical rotatory dispersion spectrum of 2′-5′-GpG is significantly different from that of 3′-5′-GpG. The magnitude of rotation of the long-wavelength peak of 2′-5′-GpG is larger than that of 3′-5′-GpG. This finding contradicts the explanation that the extra stability and more intense circular dichroism band of other 3′-5′-dinucleoside monophosphates is due to H-bond formation between 2′-OH and either the base or the phosphate oxygen. The end phosphate group has a marked effect on the spectrum of GpG between 230 and 250 mμ. In addition the optical rotatory dispersion spectra of 2′-5′ exhibit strong pH, temperature, and solvent dependence between 230 and 250 mμ. ΔH and AS for order ⇌ disorder transition is estimated to be 9.7 kcal/mole and 35.2 eu, respectively. The optical rotatory dispersion spectra of guanine-rich oligoribonucleotides, GpGpC, GpGpU, GpGpGpC, and GpGpGpU are compared to the calculated optical rotatory dispersion from the semiempirical expression of Cantor and Tinoco, using measured optical rotatory dispersion of dimers. Contrary to previous studies, agreement is found not at all satisfactory. However, optical rotatory dispersion of 3′-5′-GpGpGpC and GpGpGpU can be estimated from the semiempirical expression, if a next-nearest interaction parameter is introduced empirically. Such interaction parameter can be calculated from the measured properties of trinucleotide sequences like GpGpG, GpGpC, and GpGpU, assuming that only the nearest-neighbor interaction is important. The optical rotatory dispersion of single-stranded poly(G) is also predicted. The importance of syn-anti equilibrium and next-nearest-neighbor interaction in oligoguanylic acids is suggested as a probable explanation.

Glucose-Triggered Drug Delivery from Borate Mediated Layer-by-Layer Self-Assembly

In this study, we report a novel approach for glucose-triggered anticancer drug delivery from the self-assembly of neutral poly(vinyln alcohol) (PVA) and chitosan. In the present study, we have fabricated multilayer thin film of PVA-borate and chitosan on colloidal particle (MF particle) and monitored the layer-by-layer growth using Zetapotential measurements. Formation of multilayer membrane on MF particle has been further characterized with transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Subsequently,disintegration of multilayer thin film and microcapsules was observed in presence of glucose. We investigated the disassembly of PVA-borate and chitosan self-assembly under CLSM and atomic force microscopy. These results suggest that this multilayer thin film is very efficient for encapsulation and release of DOX molecules above certain concentration of glucose (25 mM). This glucose-sensitive self-assembly is relevant for the application of anticancer therapeutic drug delivery.

Effect of vibration on heat transfer from a horizontal cylinder to a normal air stream

The effect of vibration on heat transfer from a horizontal copper cylinder, 0.344 in. in diameter and 6 in. long, was investigated. The cylinder was placed normal to an air stream and was sinusoidally vibrated in a direction perpendicular to the direction of the air stream. The flow velocity varied from 19 ft/s to 92 ft/s; the double amplitude of vibration from 0.75 cm to 3.2 cm, and the frequency of vibration from 200 to 2800 cycles/min. A transient technique was used to determine the heat transfer coefficients. The experimental data in the absence of vibration is expressed by NNu = 0.226 NRe0.6 in the range 2500 < NRe < 15 000. By imposing vibrational velocities as high as 20 per cent of the flow velocity, no appreciable change in the heat transfer coefficient was observed. An analysis using the resultant of the vibration and the flow velocity explains the observed phenomenon.

Possible use of self-calibration to reduce systematic uncertainties in determining distance-redshift relation via gravitational radiation from merging binaries

By observing mergers of compact objects, future gravity wave experiments would measure the luminosity distance to a large number of sources to a high precision but not their redshifts. Given the directional sensitivity of an experiment, a fraction of such sources (gold plated) can be identified optically as single objects in the direction of the source. We show that if an approximate distance-redshift relation is known then it is possible to statistically resolve those sources that have multiple galaxies in the beam. We study the feasibility of using gold plated sources to iteratively resolve the unresolved sources, obtain the self-calibrated best possible distance-redshift relation and provide an analytical expression for the accuracy achievable. We derive the lower limit on the total number of sources that is needed to achieve this accuracy through self-calibration. We show that this limit depends exponentially on the beam width and give estimates for various experimental parameters representative of future gravitational wave experiments DECIGO and BBO.

Studies on nucleotide pyrophosphatase I. Partial purification and properties of a sheep liver enzyme that catalyzes the hydrolysis of dinucleotides

A partially purified sheep liver enzyme that hydrolyzed dinucleotides at the pyrophosphate bond was obtained by solubilizing the 18,000g sediment with n-butanol and fractionating the solubilized enzyme with acetone. The enzyme activity when measured using FAD as substrate, (FAD → FMN + AMP), was optimal at pH 9.7 and temperatures between 30 °–36 ° and at 60 °. The rate of release of FMN with time occurred with an initial lag of 30 sec, a linear increase for 1 min, and a subsequent irregular rate. In the presence of orthophosphate (Pi; 10 μImage ), FMN was released at an uniformly continuous and enhanced rate. 32Pi was not incorporated into the substrate or products. Sodium arsenate counteracted the effects of Pi. The apparent Km and Vmax were 0.133 mImage and 100 units; and 0.133 mImage and 200 units, in the absence and presence of Pi, respectively. The temperature optimum was 42 ° in the presence of Pi.Negative cooperative interactions observed at low concentrations of FAD were abolished by the addition of Pi. The inhibition by AMP was sigmoid and Pi abolished this sigmoidal response. The enzyme hydrolyzed in addition to FAD, NAD+ and NADP+. Nucleoside triphosphates were potent inhibitors of the enzyme activity. The partial inhibition of the enzyme by o-phenanthroline and by p-hydroxymercuribenzoate could be reversed by Fe2+ ions and by reduced glutathione, respectively.

The Role of Abduction in Self-Similarity

Based on the Aristotelian criterion referred to as 'abductio', Peirce suggests a method of hypothetical inference, which operates in a different way than the deductive and inductive methods. “Abduction is nothing but guessing” (Peirce, 7.219). This principle is of extreme value for the study of our understanding of mathematical self-similarity in both of its typical presentations: relative or absolute. For the first case, abduction incarnates the quantitative/qualitative relationships of a self-similar object or process; for the second case, abduction makes understandable the statistical treatment of self-similarity, 'guessing' the continuity of geometric features to the infinity through the use of a systematic stereotype (for instance, the assumption that the general shape of the Sierpiński triangle continuates identically into its particular shapes). The metaphor coined by Peirce, of an exact map containig itself the same exact map (a map of itself), is not only the most important precedent of Mandelbrot’s problem of measuring the boundaries of a continuous irregular surface with a logarithmic ruler, but also still being a useful abstraction for the conceptualisation of relative and absolute self-similarity, and its mechanisms of implementation. It is useful, also, for explaining some of the most basic geometric ontologies as mental constructions: in the notion of infinite convergence of points in the corners of a triangle, or the intuition for defining two parallel straight lines as two lines in a plane that 'never' intersect.

Oxidation of catechol in plants : III. Purification and properties of the diphenylene dioxide 2,3-quinone-forming enzyme system from Tecoma leaves

In attempting to determine the nature of the enzyme system mediating the conversion of catechol to diphenylenedioxide 2,3-quinone, in Tecoma leaves, further purification of the enzyme was undertaken. The crude enzyme from Tecoma leaves was processed further by protamine sulfate precipitation, positive adsorption on tricalcium phosphate gel, and elution and chromatography on DEAE-Sephadex. This procedure yielded a 120-fold purified enzyme which stoichiometrically converted catechol to diphenylenedioxide 2,3-quinone. The purity of the enzyme system was assessed by polyacrylamide gel electrophoresis. The approximate molecular weight of the enzyme was assessed as 200,000 by gel filtration on Sephadex G-150. The enzyme functioned optimally at pH 7.1 and at 35 °C. The Km for catechol was determined as 4 × 10−4 Image . The enzyme did not oxidize o-dihydric phenols other than catechol and it did not exhibit any activity toward monohydric and trihydric phenols and flavonoids. Copper-chelating agents did not inhibit the enzyme activity. Copper could not be detected in the purified enzyme preparations. The purified enzyme was not affected by extensive dialysis against copper-complexing agents. It did not show any peroxidase activity and it was not inhibited by catalase. Hydrogen peroxide formation could not be detected during the catalytic reaction. The enzymatic conversion of catechol to diphenylenedioxide 2,3-quinone by the purified Tecoma leaf enzyme was suppressed by such reducing agents as GSH and cysteamine. The purified enzyme was not sensitive to carbon monoxide. It was not inhibited by thiol inhibitors. The Tecoma leaf was found to be localized in the soluble fraction of the cell. Treatment of the purified enzyme with acid, alkali, and urea led to the progressive denaturation of the enzyme.

Cloning, expression, purification, crystallization and preliminary X-ray crystallographic study of the putative SAICAR synthetase (PH0239) from Pyrococcus horikoshii OT3

The study of proteins involved in de novo biosynthesis of purine nucleotides is central in the development of antibiotics and anticancer drugs. In view of this, a protein from the hyperthermophile Pyrococcus horikoshii OT3 was isolated, purified and crystallized using the microbatch method. Its primary structure was found to be similar to that of SAICAR synthetase, which catalyses the seventh step of de novo purine biosynthesis. A diffraction-quality crystal was obtained using Hampton Research Crystal Screen II condition No. 34, consisting of 0.05 M cadmium sulfate hydrate, 0.1 M HEPES buffer pH 7.5 and 1.0 M sodium acetate trihydrate, with 40%(v/v) 1,4-butanediol as an additive. The crystal belonged to space group P3(1), with unit-cell parameters a = b = 95.62, c = 149.13 angstrom. Assuming the presence of a hexamer in the asymmetric unit resulted in a Matthews coefficient (V-M) of 2.3 angstrom(3) Da(-1), corresponding to a solvent content of about 46%. A detailed study of this protein will yield insights into structural stability at high temperatures and should be highly relevant to the development of antibiotics and anticancer drugs targeting the biosynthesis of purine nucleotides.

Growth, self-assembly and dynamics of nano-scale films at fluid interfaces

Ultrathin films at fluid interfaces are important not only from a fundamental point of view as 2D complex fluids but have also become increasingly relevant in the development of novel functional materials. There has been an explosion in the synthesis work in this area over the last decade, giving rise to many exotic nanostructures at fluid interfaces. However, the factors controlling particle nucleation, growth and self-assembly at interfaces are poorly understood on a quantitative level. We will outline some of the recent attempts in this direction. Some of the selected investigations examining the macroscopic mechanical properties of molecular and particulate films at fluid interfaces will be reviewed. We conclude with a discussion of the electronic properties of these films that have potential technological and biological applications.

Pt2+ Dispersed in Ce0.83Ti0.15O2-delta: Significant Improvement in PROX Activity by Ti Substitution in CeO2 in Hydrogen Rich Stream

Pt2+ ion dispersed in CeO2, Ce1-xTixO2-delta and TiO2 have been tested for preferential oxidation of carbon monoxide (PROX) in hydrogen rich stream. It is found that Pt2+ substituted CeO2 and Ce(1-x)TixO(2-delta) in the form of solid solution Ce0.98Pt0.02O2-delta and Ce0.83Ti0.15Pt0.02O2-delta are highly CO selective low temperature PROX catalysts in hydrogen rich stream. Just 15% of Ti substitution in CeO2 improves the overall PROX activity.