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The enzymes of the β-ketoadipate pathway are governed by different induction mechanisms in Acinetobacter and Pseudomonas; muconolactone isomerase is one of the enzymes of the catabolic pathway. In order to determine whether the different inductive controls reflect the independent evolutionary acquisition of the pathway in the two bacterial genera, the properties of muconolactone isomerase purified from a representative of each genus were compared. Procedures previously used to crystallize the enzyme from extracts of Pseudomonas putidia were modified to permit crystallization of the enzyme from extracts of Acinetobacter calcoaceticus. The isofunctional enzymes were found to be serologically remote, and some differences in their amino acid compositions were observed. Nevertheless, the muconolactone isomerases possessed similar molecular weights (100,000 for the Acinectobacter enzyme and 94,000 for the Pseudomonas enzyme) and similar subunit sizes (12,000 for the Acinetobacter subunit and 11,500 for the Pseudomonas subunit). At least 12 (and perhaps 13) of the first 15 residues in the NH2-terminal amino acid sequences of the proteins are identical. On the basis of this evidence we conclude that the muconolactone isomerases from the two genera share a common ancestral gene. The apparently close evolutionary homology of the muconolactone isomerases and the wide evolutionary separation of Acinetobacter and Pseudomonas suggest that the structural gene for the catabolic enzyme may have been exchanged well after the divergence of other genes that dictated the evolutionary separation of the two genera. Conservation of the distinctive inductive controls that are characteristic of each genus may have resulted from selective pressures imposed by the nutritional opportunities available to each bacterial group in its natural environment.

The steady‐flow viscosity η(γ), the loss modulus G″(ω), and the storage modulus G′(ω) for five linear polyethylene melts (190°C) were measured using the Weissenberg rheogoniometer and the Instron rheometer. An excellent agreement was observed between the experimental G′(ω) and G″(ω) values and those calculated from the relaxation spectrum obtained from η(γ) using the relation η(γ)=∫H(lnτ)h(θ)g(θ)3/2τd lnτ, θ=γτ/2. Here, γ is the shear rate, ω is the radian frequency, and τ is the relaxation time. The functions g(θ) and h(θ) are expressed as g(θ)=(2/π)[cot−1θ+θ/(1+θ2)] and h(θ)=(2/π)[cot−1θ+θ(1−θ2)/(1+θ2)2]. No coordinate shift was required. An interative procedure was used in such an interconversion. The first approximation to the spectrum H1(lnτ) was (2/π)[η(γ)×γ] and the corresponding viscosity was η1(γ). The successive approximations were expressed by the equation HK(lnτ)=HK−1(lnτ)+pγ[η(γ)−ηK−1(γ)], where p=2/π and K≥2. In all cases, only six iterations were required to achieve satisfactory convergence. The relaxation spectra so obtained from viscosity measurements at large shearing deformation were in excellent agreement with those calculated from G″(ω) measured in oscillatory experiments carried at small deformation.

The purpose of this paper is to describe the incremental dynamic anisotropic viscoelastic properties of the middle descending thoracic aorta in ten living dogs. A segment of the middle descending thoracic aorta was isolated in situ and connected to a reservoir filled with oxygenated blood. The height of the reservoir could be adjusted to impress a known pressure on the segment. In addition, a sinusoidal fluid displacement pump was connected to this assembly to superimpose small sinusoidal pressures at various frequencies (0-5 Hz); in another phase of the experiment small sinusoidal changes in length were also imposed on the segment. The pressure, the longitudinal force, and the length of the segment were monitored continuously with specially designed transducers. From these data, the incremental elastic ( E ') and the viscous ( E '') moduli in the circumferential (θ), longitudinal ( z ), and radial (γ) directions were calculated around a given state of strain in the physiological range. In general, the viscoelastic moduli were functions of the initial stretches, indicating the nonlinear nature of the arterial wall. Within the physiological range of pressure, E z ' > E θ ' > E γ ' ( P < 0.01) and E z '' > E γ '' > E θ '' (P < 0.01). These results indicated that the vessel wall was anisotropic, having its largest values of elastic and viscous moduli in the longitudinal direction. The ratio of E ' / E ' < 0.123 at 2 Hz, indicating a small viscous component relative to its elastic counterpart. The elastic moduli increased markedly from 0-2 Hz and then settled down to a relatively constant value; this finding was consistent with previously published data. The values of E z ' and E z '' from the in vivo experiments were higher than those from the in vitro experiments, and the difference was attributed to the vascular tethering present in the in vivo state.

Photochemical reactions of various tricovalent phosphorus ligands with the three metal carbonyl trifluoroacetates CF3CO2Fe(CO)2C5H5, CF3CO2Mn(CO)5 and CF3CO2Fe(CO)3C3H5 are described. From various reactions of CF3CO2Fe(CO)2C5H5 with the phosphorus ligands the following new complexes were prepared: (1) Violet CF3CO2Fe(diphos)(C5H5) (diphos = chelating ditertiary phosphine); (2) CF3CO2Fe(CO)(PR3)(C5H5) (R = C6H5 [green] and OC6H5 [red-brown]; (3) Red-brown CF3CO2Fe[P(OCH3)3]2(C5H5). From various reactions of CF3CO2Mn(CO)5 with the phosphorus ligands the following new complexes were prepared: (1) Yellow CF3CO2Mn(CO) [(CH3)2PCH2CH2P(CH3)2]2; (2) Yellow cis-CF3CO2Mn(CO) 3(diphos) (diphos = (C6H5)32PCH2- CH2P(C6H5)2 or cis-(C6H5)2PCH CHP(C5H5)2); (3) Yellow trans-CF3CO2Mn(CO)3 [P(OC6H5)3]2; (4) Yellow cis-CF3CO2Mn(CO)2[P(OCH3)3]3. The i.r. and NMR spectra of the new complexes are discussed.

The steady flow viscosity η and the dynamic viscosity η′ of several linear polyethylene melts (190°C) were measured using the Weissenberg rheogoniometer and the Instron rheometer. In correlating the two viscosities, the use of Graessley's theory of viscosity in steady shearing flow in combination with the box distribution of relaxation times as suggested by Maruyama et al. has been critically examined. The new approach discussed in this paper uses Graessley's functions h(θ) and g(θ) in conjunction with the relaxation spectrum H(τ) derived from linear viscoelastic data using an iterative method. The required relation is η(γ)=∫H(τ)h(θ)g(θ)3/2τd ln τ, θ=γτ/2; where γ is the shear rate and τ is the relaxation time. Here g(θ)=(2/π) [cot−1 θ+θ/(1+θ2)] and k(θ)=(2/π) [cot−1 θ+θ (1−θ2)/(1+θ2)2]. A good agreement was obtained in all cases without involving any coordinate shift. The approach illustrated in this article enabled us to estimate quantitatively the effect of shear rate on the relaxation spectrum and ...

Reactions of various π-cyclopentadienyl and carbonyl halides with silver perfluorocarboxylates in dichloromethane solution yield new organometallic transition metal perfluorocarboxylates by metathetical reactions. The following types of compounds have been prepared: (a) red-orange, RfCO2Fe(CO)2C5H5; (b) red-brown RfCO2Mo(CO)3C5H5; (c) yellow RfCO2Mn(CO)5; (d) white RfCO2Re(CO)5; (e) yellow-orange [C5H5Mo(NO)(CO2Rf)2]2; (f) yellow RfCO2Fe(CO)3(π-C3H5); (g) red-brown RfCO2Co(CO)(C3F7)(C5H5); (h) red-orange (C5H5)2Ti(CO2Rf)2; (i) white (C5H5)2Zr(CO2Rf)2. In most cases the trifluoroacetates (Rf = CF3), pentafluoropropionates (Rf = C2F5), and heptafluorobutyrates (Rf = n-C3F7) were prepared. In these compounds the perfluorocarboxylate groups appear to be bonded to the transition metal thru the oxygen atom. They exhibit a characteristic v(CO) frequency in the range 1680-1730 cm-1 arising from the carbonyl group of the perfluorocarboxylate ligand. The force constants k1, k2, and ki calculated from the v(CO) frequencies in the RfCO2M(CO)5 (M = Mn or Re) compounds by the Cotton-Kraihanzel procedure were found to be similar to those in the metal carbonyl halides M(CO)5X (M = Mn or Re) indicating similar bonding properties of the perfluorocarboxylate and halide ligands.

The direct relation between the complex longitudinal modulus E* and the experimentally measured quantities—the amplitude ratio A and phase angle φ—has been derived for the forced vibrating reed instrument and is given by: exp (iφ)/A=1+∑K=1∞(−ω2ρ/E*)K[AK+BKρ−1+CKρ−2+….], where terms in ρ with negative exponents are not admitted. E* is equal to E′+iE″, where E′ is the longitudinal storage modulus and E″ is the longitudinal loss modulus. A is the ratio of the amplitude of the free end of the reed—either loaded with a pin or unloaded—to that of the clamped sinusoidally driven end and φ is the angle by which the former lags the latter. In practice, the sample dimensions and frequency range are chosen such that the sum in the above equation is rapidly convergent. The dynamic moduli then can be calculated by including only up to the first two or three terms in the sum. Where phase measurements are relatively inconvenient to make and when all but the first term under the sum can be neglected, the equation can be used to calculate dynamic moduli from two amplitude measurements at the same frequency for reeds of two different lengths; or from amplitude at resonance alone, provided E″≪E′. Illustrative examples are given. The procedures for calculating the dynamic moduli are applicable to the data obtained in all experiments where a relation of the form given above is obtained.The direct relation between the complex longitudinal modulus E* and the experimentally measured quantities—the amplitude ratio A and phase angle φ—has been derived for the forced vibrating reed instrument and is given by: exp (iφ)/A=1+∑K=1∞(−ω2ρ/E*)K[AK+BKρ−1+CKρ−2+….], where terms in ρ with negative exponents are not admitted. E* is equal to E′+iE″, where E′ is the longitudinal storage modulus and E″ is the longitudinal loss modulus. A is the ratio of the amplitude of the free end of the reed—either loaded with a pin or unloaded—to that of the clamped sinusoidally driven end and φ is the angle by which the former lags the latter. In practice, the sample dimensions and frequency range are chosen such that the sum in the above equation is rapidly convergent. The dynamic moduli then can be calculated by including only up to the first two or three terms in the sum. Where phase measurements are relatively inconvenient to make and when all but the first term under the sum can be neglected, the equation can be ...

A model is proposed for stress analysis of the left ventricular wall (LV wall) based on the realistic assumption that the myocardium is essentially composed of fiber elements which carry only axial tension and vary in orientation through the wall. Stress analysis based on such a model requires an extensive study of muscle fiber orientation and curvature through the myocardium. Accordingly, the principal curvatures were studied at a local site near the equator in ten dog hearts rapidly fixed in situ at end diastole and end systole; the fiber orientation for these hearts had already been established in a previous study. The principal radii of curvature were (a) measured by fitting templates to the endocardial and epicardial wall surfaces in the circumferential and longitudinal directions and (b) computed from measured lengths of semiaxes of ellipsoids of revolution representing the LV wall (“ellipsoid” data). The wall was regarded as a tethered set of nested shells, each having a unique fiber orientation. Results indicate the following. (a) Fiber curvature, k, is maximum at midwall at end systole; this peak shifts towards endocardium at end diastole. (b) The pressure or radial stress through the wall decreases more rapidly near the endocardium than near the epicardium at end diastole and at end systole when a constant tension is assumed for each fiber through the wall. (c) At end diastole the curve for the circumferential stress vs. wall thickness is convex with a maximum at midwall. In the longitudinal direction the stress distribution curve is concave with a minimum at midwall. Similar distributions are obtained at end systole when a constant tension is assumed for each fiber through the wall. (d) The curvature and stress distributions obtained by direct measurements at a selected local site agree well with those computed from “ellipsoid” data.

The theory of locating a deep submersible by measurement of time delays in arrival of an acoustic pulse from the deep submersible to three hydrophones of a short‐base navigational system has been developed in detail. The theory incorporates all the relevant variables such as the translational and rotational positions and velocities of the tracking ship and the variation of acoustic speed with depth. No restrictions have been placed on the relative values of the horizontal and vertical coordinates of the submersible relative to the tracking ship. A numerical example is given to demonstrate the use of the theory and to show the effects of ignoring the motion of the tracking ship and the variation of acoustic speed with oceanic depth.

Ultraviolet irradiation of the perfluoroalkyliron derivatives RfFe(CO)2C5H5 [Rf=C2F5 and (CF3)2CF] with the saturated chelating ditertiary phosphine (C6H5)2PCH2CH2P(C6H5)2(Pf-Pf) results in stepwise substitution of the carbonyl groups giving first the monodentate monometallic derivatives RfFe(CO)(Pf-Pf)(C5H5) and then the carbonyl-free bidentate monometallic derivatives RfFe(Pf-Pf)(C5H5). By contrast, UV irradiation of the same perfluoroalkyliron derivatives with the unsaturated chelating ditertiary phosphine cis-(C6H5)2PCH=CHP(C6H5)2 (cPf=Pf) proceeds directly to the carbonyl-free bidentate monometallic derivatives RfFe(cPf=Pf)(C5H5) without formation of an isolable monodentate monometallic derivative. UV irradiation of the RfFe(CO)2C5H5 derivatives with triphenylphosphine gives the substitution products RfFe(CO)[P(C6H5)3](C5H5) (Rf=CF3, CF3CO, C2F5, and (CF3)2CF); IR and NMR spectral data on the compound of this type with the relatively bulky (CF3)2CF group suggest the presence of conformational isomers arising from hindered rotation about the iron-perfluoroalkyl bond. Similar UV irradiation of the molybdenum derivative CF3Mo(CO)3C5H5 with the appropriate tertiary phosphines gives the substitution products CF3Mo(CO)2[P(C6H5)3](C5H5) and CF3Mo(CO)(Pf-Pf)(C5H5). An improved preparation of the RfFe(CO)2C5H5 [Rf=C2F5F and (CF3)2CF] derivatives from the corresponding perfluoroalkyliron tetracarbonyl iodides RfFe(CO)4I and thallium(I) cyclopentadienide is described.

Methylococcus capsulatus grows only on methane or methanol as its sole source of carbon and energy. Some amino acids serve as nitrogen sources and are converted to keto acids which accumulate in the culture medium. Cell suspensions oxidize methane, methanol, formaldehyde, and formate to carbon dioxide. Other primary alcohols are oxidized only to the corresponding aldehydes. Oxidation of formate by cell suspensions is more sensitive to inhibition by cyanide than is the oxidation of other one carbon compounds. This is due to the cyanide sensitivity of a soluble nicotinamide adenine dinucleotide-specific formate dehydrogenase. Oxidation of formaldehyde and methanol is catalyzed by a nonspecific primary alcohol dehydrogenase which is activated by ammonium ions and is independent of pyridine nucleotides. Some comparisons are made with a strain of Pseudomonas methanica .

The steady-state viscosity η, the dynamic viscosity η′, and the storage modulus G′ of several high-density and low-density polyethylene melts were investigated by using the Instron rheometer and the Weissenberg rheogoniometer. The theoretical relation between the two viscosities as proposed earlier is:, where ; is the shear rate, H is the relaxation spectrum, τ is the relaxation time, , and . Good agreement between the experimental and calculated values was obtained, without any coordinate shift, for high-density polyethylenes as well as for a low density sample with low nw, the weight-average number of branch points per molecule. The correlation, however, was poor with low-density samples with large values of the long-chain branching index nw. This lack of coordination can be related to nw. The empirical relation of Cox and Merz failed in a similar way.

Limitations on the use of the equations [η] = {2(ηsp − ln ηre1)}1/2/c and [η] = (ηsp + 3ln ηre1)/4c in determining intrinsic viscosity, [η], by a single point method have been pointed out. Inclusion of higher order terms in the series expansion for ln ηre1 introduces an additional term in the above equations which is negligible when the value of Huggins' constant, k′, is in the vicinity of 0.3–0.4. More accurate values for intrinsic viscosity calculated by a single point method can be obtained using these modified equations provided k′ can be estimated.

Interrelations were established, in a limited range of shear rate γ, among the non-Newtonian shear stress relaxation following cessation of steady-state flow σ(γ, t), the steady-flow viscosity η(γ), and the dynamic viscosity η(ω) or the storage modulus G′(ω) for three linear polyethylene melts (190°C). The data for these melts were obtained using the Weissenberg rheogoniometer and the Instron rheometer. Agreement between the experimental σ(γ, t) and those calculated from the relaxation spectrum H(ln τ) was good and involved no coordinate shift. The calculated values were obtained through the relation where θ = γτ/2, τ is the relaxation time, ω is the radian frequency, h(θ) = (2/π)[cot−1 θ + θ(1 - θ2)/(1 + θ2)2], andg(θ) = (2/π) [cot−1 θ + θ)/(1 + θ2)]. The relaxation spectrum was obtained either from the linear viscoelastic data [η(ω)] using the iterative method of Roesler and Twyman or from the nonlinear steady-flow viscosity using the iterative procedure based on the equation

Dynamic mechanical properties of several polyethylene melts were investigated using the Weissenberg rheogoniometer. The use of the rheogoniometer for oscillatory shear testing has been discussed. The methods of determining relaxation spectrum from loss modulus based on second‐order approximation of Schwarzl and Staverman, and first‐ and second‐order approximations of Ninomiya and Ferry were found relatively inaccurate in reproducing the original loss modulus and storage modulus data. As a result, the iterative procedure based on Roesler and Twyman's derivation and that based on Tanner's algorithm were employed and found to regenerate accurately the original experimental data. Of all the approximation methods, the one based on the second‐order approximation method of Williams and Ferry was subject to least error in its ability to regenerate the original melt data.

This article uses Graessley's theory of viscosity to predict the flow curve for several high-density and low-density polyethylene melts using the molecular weight distribution data obtained from the gel permeation chromatograph. The agreement with the experimental flow curve obtained from the Weissenberg rheogoniometer and the Instron rheometer was not quantitative for many high-density polyethylenes studied here. For the low-density polyethylenes, it was shown that the agreement between the theory and the experiment was good even though the molecular weight distribution data were not corrected for long-chain branching. For these samples, the experimental relaxation time τ0 obtained by superposition of the data with the theoretical master curve was of the order of the Rouse relaxation time τR. The systematic increase in the ratio τR/τ0 was ascribed to the increase in the molecular weight or to the increased number of long-chain branches.

Reactions of niobium and tantalum pentaethoxides with various α-hydroxy carboxylic acids (lactic, mandelic, and salicylic acid) have been studied in different stoichiometric ratios and compounds having the composition, M(OEt) 3 (C 3 H 4 O 3 ), M(OEt)(C 3 H 4 O 3 ) 2 , M- (C 3 H 5 O 3 (C 3 H 4 H 4 O 3 ) 2 , M(OEt) 3 (C 8 H 6 O 3 ), M(OEt)(C 8 H 6 O 3 ) 2 , M(C 8 H 7 O 3 )(C 8 H 6 O 3 ) 2 , M(OEt) 3 (C 7 H 4 O 3 ), M(OEt)(C 7 H 4 O 3 ) 2 and M(C 7 H 4 O 3 ) 2 (C 7 H 5 O 3 ) (where M is niobium or tantalum) have been quantitatively isolated. These products are either viscous liquids or crystalline solids. The above mono-substituted derivatives are monomeric in boiling benzene.

The constituents of the hydrodistilled essential oil from the roots and rhizomes of Anemopsis californica have been examined. Thymol was identified from the phenolic fraction of the oil. Gas chromatography on Hyprose SP-80 followed by collection of effluent fractions and comparison of their IR spectra with those of pure samples confirmed the presence of methyleugenol as the major constituent. A third constituent of the oil was found to be piperitone. Methyleugenol (approximately 55 percent v/v of the oil), thymol (13 percent), and piperitone (5 percent) together make up approximately 74 percent of the oil. A fourth constituent, tentatively identified as an aromatic unsaturated ether, and other constituents are being investigated.

An alternating series expression relating the complex dynamic viscosity, η*, to the experimentally measured quantities—the amplitude ratio m and phase angle ϕ—has been derived for bob-in-cup and ring-in-cup geometries. It is similar in form to that derived for a vibrating reed [10]. Both Taylor series and asymptotic expansion of Bessel functions for any one geometry gives similar results. A general condition for the convergence or the useful range of the series expressions is given and the direct analytical expressions are derived for calculating G′ , G″ , and tan δ when certain terms in these series can be excluded.

In this paper we presented a method for determining the distribution of circumferential ( S θ ), longitudinal ( S z ), and radial ( S r ) stress and of strain-energy density ( W ) in canine aortic segments under physiological loading. Aortic segments from 13 dogs were studied in vitro. Intraluminal pressure and longitudinal force were varied over ranges of 25 to 200 cm H 2 O and 0 to 100 g, respectively, and the external radius and the segment length were measured at each step. A nonlinear theory of large deformation of the aortic tissue based on the assumptions of incompressibility and curvilinear orthotropy was applied to the data. The 3, 7, or 12 constitutive constants of the theory were calculated without using the usual thin-wall assumption. These constants were then used to calculate the distribution of stresses and of W . The results indicated that (I) S θ , S z , S r , and W were largest in magnitude at the endothelial surface and decreased toward the adventitial surface, (2) the decrease was most marked in the inner third of the vessel wall, (3) in general S θ > S z > W > S r , and (4) at a given longitudinal stretch an increase in intraluminal pressure increased S θ , S z , | S r |, and W , with the effect being most marked on S θ .

The assumption of incompressibility has often been applied to the analysis of arterial-wall elasticity; however, the supporting evidence has been incomplete. The present study was designed to explore this problem in greater depth by accurately measuring the changes in tissue volume associated with large, induced strains on 11 thoracic aorta segments excised from dogs. The radial, circumferential, and longitudinal stresses were measured as the artery was subjected to an internal pressure and longitudinal stretch greater than those in vivo. From these data it was possible to calculate the hydrostatic stress. The associated changes in volume of the aortic wall tissue were measured with a specially designed apparatus. The greatest volumetric strain (ΔV/V) was 0.00165. The bulk moduli obtained by dividing the hydrostatic stresses by the corresponding volume strains averaged 4.44 x 10 6 g/cm 2 . Similar studies were also carried out on the abdominal aorta and the carotid, iliac, and pulmonary arteries. The volumetric strains observed were of the same magnitude. It is concluded that for most practical purposes arteries may be considered incompressible.