Slight Shoulder Research Articles

Qualitative changes in DNA indicating differential DNA replication during early embryogenesis of the newt Triturus vulgaris

During gastrulation of the newt Triturus vulgaris considerable changes in the melting behaviour and in the CsCl density gradient pattern of DNA occur. The melting curves of DNAs from mid to late gastrulae (stages 11b-12c) deviate from the regular shape. Whereas the Tm values are identical in the stages 11a (early gastrula) and 15 (early neurula), and correspond to the standard DNA (stage 36 = tailbud), a significant rise of Tm (0.8-1.2 degrees C) has been recorded in the stages 12a/b (yolk plug). The differences in melting behaviour become visible by the deviation of the curves above Tm. These deviations from the normal sigmoidal shape are caused by the fact that a portion of DNA melts at higher temperatures than usual. Therefore the thermal denaturation of DNA is completed at approximately 3-4 degrees C later than in standard DNA. Both the derivative curves and the plots on normal probability paper demonstrate a heterogeneity of DNA in the stages 11b-12c which indicates the presence of an additional GC-rich satellite fraction. These findings are confirmed by CsCl density gradient studies. Thus, in the stages 12a/b a slight shoulder on the heavy side of the gradients occurs, being absent in the other stages. From these facts we have to conclude that there is a stage-dependent multiplication and elimination of GC-rich sequences.

The role of structural iron(III) in the UV absorption by smectites

AbstractUV-visible light absorption spectra of dilute suspensions of standard and commercial montmorillonites (bentonites) and of nontronite, hectorite and pyrophyllite, were studied.All montmorillonites exhibit either an absorption band or a shoulder at a wavelength of 245 nm. The absorption peak for nontronite is shifted to 260 nm and absorption intensity is very high. Hectorite exhibits a very slight shoulder whereas pyrophyllite shows almost none. Absorption intensity in the UV range was found to be in direct correlation to structural octahedral Fe(III) contents. Direct evidence for the role of Fe(III) in the specific UV absorption of smectites was obtained by the fact that reduction with hydrazine fumes resulted in the disappearance of the peak and reoxidation with H2O2 caused its reappearance with even stronger intensity than originally. Mössbauer spectra showed that the Fe(III) disappeared almost completely in the reduced clay.

Studies on Nitrate Reductase of Clostridium perfringens

Nitrate reductase (NaR) linked to reduced methyl viologen from Clostridium perfringens was purified by ammonium sulfate precipitation. DEAE-cellulose chromatography, disc electrophoresis on polyacrylamide gel, and triple DEAE-Sephadex chromatography. The specific activity was increased 1,200-fold with a yield of 9%. The purified preparation was nearly homogeneous in disc electrophoresis. It was brown, and its spectrum showed a slight shoulder near 420 nm as well as a peak at 280 nm. The molecular weight was found to be 90,000 based on s020,w (5.8S) and 80,000 by Sephadex G-100 gel filtration. In SDS-polyacrylamide electrophoresis, it showed only a single band with a molecular weight of 90,000; it had no subunit structure. The isoelectric point was pH 5.5, and the optimum pH was 9. Mn2+, Fe2+, Mg2+, and Ca2+ stimulated the activity. Km for nitrate was 0.10 mM, and nitrate was stoichiometrically reduced to nitrite in the presence of 2 mM Mn2+. Ferredoxin fraction obtained from extracts of the bacterium was utilizable as an electron donor at pH 8. Cyanide and azide inhibited the enzyme. The formation of NaR was induced by nitrate and inhibited by 0.5 mM tungstate, but recovered in the presence of 0.1 mM molybdate; NaR of C. perfringens appears to be a molybdo-iron-sulfur protein.

The effects of concentration and heating or cooling rate on the DTA curves of Al-Ce alloys

The crystallization of Al-Ce alloys was studied by DTA. The melting and freezing DTA curves of the investigated alloys exhibit two peaks, corresponding to the transformations of a high-purity phase and the eutectic phase, respectively. The peaks could be separated during both freezing and melting by changing the heating or cooling rate. The final temperature of the phase transformation is marked by the starting temperature of the second peak. A slight shoulder on the DTA peak, even on the opposite side to the maximum point, may correspond to the final temperature. The connection between the reaction time and the peak temperature for the sample was studied at different cooling and heating rates. It was concluded that a knowledge of the structure and composition of the studied system is necessary in the interpretation of the DTA curves.

Optical conductivity of rare-earth thin films in relation to their crystalline structure and electronic configuration

The influence of the crystalline and electronic structures of light, heavy and alkaline rare earths on their optical properties in the energy range extending from 1.6 to 6.2 eV is demonstrated. The data show that the optical conductivity differs for each group. Results are given for trivalent La (d.h.c.p.) and Lu (h.c.p.) and divalent Yb (f.c.c.) and Eu (b.c.c.). Light and heavy rare earths exhibit an absorption peak whose position near 5.7 eV is practically independent of thickness. For heavy rare earths another broad peak occurs between 2.5 and 3.2 eV. In contrast, Yb and Er behave like the alkaline metals Sr and Ba respectively. In the UV range the conductivity of Eu exhibits a broad peak between 4.5 and 5.15 eV. Such a structure does not occur for Yb in this range. In the IR range a slight shoulder is found near 2.12 eV for Eu and near 2.8 eV for Yb. Theoretically, we suggest the presence of indirect transitions between the 4f states and the Fermi level, which give rise to the structure near 5.7 eV for light and heavy metals. For the latter, the mean value of the energies associated with allowed direct interband transitions agrees with the optical anomaly located between 2.5 and 3.5 eV. For Eu, interband transitions occur between 4 and 5.5 eV. The phenomena which occur between 1.5 and 2.4 eV are correlated with the granular structure of the films. For Yb, interband absorption occurs at higher values (above 6 eV).

Optical conductivity of rare earth thin films in relation to their crystalline structure and electronic configuration

Abstract The influence of the crystalline and electronic structures of light, heavy and alkaline rare earths on their optical properties in the energy range extending from 1.6 to 6.2 eV is demonstrated. The data show that the optical conductivity differs for each group. Results are given for trivalent La (d.h.c.p.) and Lu (h.c.p.) and divalent Yb (f.c.c.) and Eu (b.c.c.). Light and heavy rare earths exhibit an absorption peak whose position near 5.7 eV is practically independent of thickness. For heavy rare earths another broad peak occurs between 2.5 and 3.2 eV. In contrast, Yb and Er behave like the alkaline metals Sr and Ba respectively. In the UV range the conductivity of Eu exhibits a broad peak between 4.5 and 5.15 eV. Such a structure does not occur for Yb in this range. In the IR range a slight shoulder is found near 2.12 eV for Eu and near 2.8 eV for Yb. Theoretically, we suggest the presence of indirect transitions between the 4f states and the Fermi level, which give rise to the structure near 5.7 eV for light and heavy metals. For the latter, the mean value of the energies associated with allowed direct interband transitions agrees with the optical anomaly located between 2.5 and 3.5 eV. For Eu, interband transitions occur between 4 and 5.5 eV. The phenomena which occur between 1.5 and 2.4 eV are correlated with the granular structure of the films. For Yb, interband absorption occurs at higher values (above 6 eV).

Inhibition of NADP-dependent dehydrogenases by modified products of NADPH

When NADPH was incubated at neutral pH, a modified product which had no absorbancy at 340 nm, but exhibited a slight shoulder in the region of 280–300 nm with maximum absorbancy at 266 nm, was produced. Phosphate accelerated the conversion. This compound was tentatively designated as NADPH-X. At acidic pH, NADPH was rapidly converted to the primary acid-modified product which had a similar, but not identical, absorption spectrum to that of NADPH-X, and it was gradually converted to the secondary acid-modified product which exhibited a distinctive absorption spectrum with a maximum at 261 nm. NADPH-X strongly inhibited human glucose 6-phosphate dehydrogenase, human 6-phosphogluconate dehydrogenase, and yeast glucose 6-phosphate dehydrogenase. The primary acid-modified product inhibited human 6-phosphogluconate dehydrogenase, but human and yeast glucose 6-phosphate dehydrogenases were not sensitive to this compound. The secondary acid-modified product inhibited the three dehydrogenases. The mode of the dehydrogenase inhibition by these compounds was competitive with NADP. Potential physiologic role of NADPH-X was discussed.

沖繩毒魚肝臓中の水溶性の毒,シガテリンの分離

Ciguaterin, an emetic factor, was extracted from the liver of the red snapper Lutjanus bohar from the Ryukyu Islands and purified by column chromatography using ion-exchange resins, acidic alumina, silicic acid, and Sephadex G-10 successively. The final product evoked vomiting in cats within 30min at a dose as low as 3μg/kg. It was however still contaminated by a few ninhydrin-positive substances, as shown by thin-layer chromato-graphy. The purified emetic was positive to ninhydrin, peptide and Pauly reagents, but negative to Dragendorff and sugar reagents. It showed only a slight shoulder near 330nm in the ultraviolet region. On acid hydrolysis, it afforded 14 amino acids, of which lysine, glutamic and aspartic acids were prominent. Total amino acid residues accounted for 40 per cent of the solid. These results suggest that ciguaterin possesses a peptide moiety.

Cryogenic Relaxations in Tough Amorphous Polymers

Abstract The dynamic mechanical behavior of five phenyl containing polymers was studied at temperatures from 4.2 to 300TC using a free oscillating torsional pendulum. Polycarbonate (PCA) was found to have two relaxations γ and δ at 165 and 40–50°K, respectively. Orientation increases the temperature of the PCA γ relaxation from 165 to 170°K and crystallization causes a decrease in the intensity of the y relaxation, but neither of these forms of molecular organization seem to affect the δ relaxation to any great extent. In addition to the previously reported γ relaxation at 300°K, melt cast polyphenylene oxide (PPO) has δ and ε relaxations at 75 and 12°K respectively. Residual solvent in PPO cast from CHC13 changes its mechanical spectra drastically, shifting the γ relaxation from 300 to 250°K, splitting the δ relaxation into two processes having maxima at 120 and 45°K and shifting the ε peak from 12 to 15°K. Amorphous poly(cyclohexylene dimethylene terephthalate) (CHDMT), whose mechanical spectra is previously unreported, has a very intense (Δ = 0.195) γ relaxation at 205°K which decreases in intensity when the polymer is crystallized. Below 80°K the internal friction of CHDMT is very weak with only a slight shoulder at 50°K and a small increase in intensity as the temperature drops from 20 to 4.2°K. The Polyimide (Kapton) has a low level of damping at all temperatures below room temperature with only one small (Δ = 0.020) relaxation at 180°K.

The Rotatory Dispersion and Stereochemistry of Organic Compounds. XIV. Nitrobenzylidene Derivatives of Diethyl d-Tartrate

Abstract Anomalous optical rotation has been observed not only with the ortho-nitrobenzylidene derivative of diethyl d-tartrate (Tsuzuki, Bull. Chem. Soc. Japan, 14, 35 (1939); Sci. Pap. I. P. C. Res. (Tokyo), 35, 425, 466 (1939)), but also with some acetylated ortho-nitrophenyl glycosides of the β-type (Capon et al., J. Chem. Soc., 1961, 5172; Montgomery et al., J. Am. Chem. Soc, 64. 690 (1942); Snyder et al., ibid., 75, 1758 (1953); Tsuzuki et al., Bull. Chem. Soc. Japan, 40, 1208 (1967)). To investigate this anomalous effect of the ortho-nitro group the authors have made rotatory dispersion studies on several derivatives of diethyl d-tartrate as well as its alkylidene derivatives. Of these compounds examined, the compound (I) with a nitro group in the ortho-position of the phenyl group shows a positive Cotton effect at about 340 mμ, and it has been found that the nitrophenyl group is optically active. Furthermore, in order to inquire into this anomaly the authors have observed the CD, UV and NMR spectra of these compounds, from which it is concluded that the conformations of the acetal rings of all the compounds are nearly equal, and the anomalous dispersion of the compound I at about 340 mμ, is assumed to be due to the n→π* transition of the nitro group with a slight shoulder appearing at 325 to 350 mμ. In view of these facts it is considered that the ortho-nitro group is twisted from the plane of the benzene ring caused by the steric hindrance of the bulky acetal ring.

Analysis and Model of Low-EnergyΛK0Production

The low-energy $\ensuremath{\Lambda}{K}^{0}$ production data are analyzed under the assumption of a ${K}^{*}$-exchange background. A new interesting result is found; namely, that the observed anomaly in the polarization and slight shoulder in the cross section at 829 MeV is apparently due to a narrow ${F}_{\frac{5}{2}}$ resonance located at 1647 MeV. The parameters of this resonance are determined from the data by adding its contribution to a model proposed previously by the author, which gave fairly good results above and below the energy of the anomaly, after modifying the contribution from a ${P}_{\frac{1}{2}}$ resonance included in that model by taking into account the proper threshold behavior. Fits to all the data up to 1.03 BeV/c (900 MeV) (the region of validity of the previous model) are given. The result obtained for the product of relative partial widths agrees remarkably well with that predicted by unitary symmetry for a member of an octet with an asymmetry parameter of 0.674 (Carruther's model). It is also found that the ${P}_{\frac{1}{2}}$ resonance (if it exists) cannot be a member of an octet, but it has to belong to either a $\overline{1}\overline{0}$ or 27 representation, if the ${F}_{\frac{5}{2}}$ resonance belongs to an octet. Experiments which might confirm or deny the existence of these resonances are suggested. Further, our method of analysis is extended to a more general type of background which includes contributions from the nucleon pole and baryon exchange terms.

Arabiens arkæologi

Arabiens arkæologi

Fission of Uranium-238 Induced by 55 MeV Protons

Distributions of fragment kinetic energies and masses in the 55 MeV proton-induced fission of U 238 have been measured in various directions with respect to the beam by using a back-to-back arrangement of surface-barrier detectors. The observed energy distribution showed a single broad peak with a slight shoulder on the high energy side. This indicates a marked growth of symmetric fission. The most probable value of the total fragment kinetic energy was observed to be 156±5 MeV. The initial total kinetic energy before neutron emission was estimated from the value to be about 161 MeV. The mass distribution obtained in the transverse direction was in fair agreement with the radiochemical result. By making a fine comparison between these results, an attempt was made to obtain some information about neutron yields from individual fragments. The mass distribution in the backward direction was almost the same in shape as in the transverse direction, when corrected for the projectile momentum. Furthermore, the o...

Paramagnetic Studies of Radiation Damage in Silica Gel

Several paramagnetic resonances and a color center in irradiated silica gel are reported. Irradiations were carried out using a Co/sup 60/ source of approximately -700 curies. At the ambient irradiation temperature of approximately -50 deg , a very sharp paramagnetic resonance is produced at a spectroscopic splitting factor of g = 2.0005 plus or minus 0.0005, which is only a few gauss in width. The resonance displays some g anisotropy seen as a slight shoulder on the low-field side, it is easily saturated at low power, and is not greatly changed by cooling to -196 deg C The maximum radiation yield for production of this line is approximately -0.1 center/l00 ev absorbed. The irradiation of degassed silica gels at -196 deg C produces a second, somewhat broader line immediately on the low-field side of the first line. This line could not be saturated with microwave power and is unaffected by added gases when kept cold. Brief warming of the sample destroys the line. Additions of oxygen to gels irradiated at -196 deg C causes the slow appearance of an orange color, but leaves the PMR spectrum unaffected. If oxygen is present during the low- temperature irradiation, both a marked reddish-orangemore » and a third, very strong, broad resonance at g = 2.0061 plus or minus 0.001 are developed. The radiation yield G is approximately 0.3 center/l00 ev absorbed. The sharp resonance at g = 2.0005 probably arises from an electron trapped at an oxygen vacancy, because it disappears upon oxygen absor tion at 25 deg C. The very broad resonance at g = 2.0061 appears to be a radiolysis product of a condensed oxygen phase stabilized by adsorption on the gel. (B.O.G.)« less

Protons from the p+d Breakup Reaction at Proton Energies of 14 MeV and 10 MeV

The energy spectra of the protons from the p + d breakup reaction as a function of angle were measured for the incident proton energies of 13.9 MeV and 10.1 MeV, using a particle selecting counter telescope consisting of a three- or five-layer proportional counter for the energy loss measurement and of an NaI scintillation counter for the energy measurement. Each of the observed energy spectra shows a rather steep rise at the maximum energy followed by a slight shoulder at large angles at the incident proton energy of 14 MeV, while the energy spectra at small angles do not show such shoulder. For both energies, each of the spectra has a maximum in its low energy side.

無発熱性医薬品の製造に関する研究 (第7報)

Effect and mechanism of pyrogen removal by quinone treatment were examined spectrochemically.1) The simple solution of culture filtrate containing pyrogen used in the present series of experiments showed a slight shoulder of absorption at 260mμ but did not show any absorption spectrum which would offer evidence of a presence of pyrogen.2) On the application of quinone to the pyrogen-containing culture filtrate, the optical density of quinone itself in the ultraviolet region decreased, the solution acquired a reddish color, and there appeared an absorption maximum at 390mμ. As an example of pyrogenic substance, albumin was treated with quinone and in this case, optical density at 420mμ increased together with the increase in the red color. These facts confirm that a reaction product (PQ) has been formed between pyrogen and quinone.3) Pyrogen-containing filtrate solution and substances giving positive TBP reaction, when treated with quinone and activated carbon to solutions negative to TBP reaction, do not show any absorption and confirm the removal of pyrogen spectrochemically.4) The activated carbon used for quinone treatment was digested with water and this solution showed the absorption again, indicating that the pyrogen adsorbed on the carbon had been dissolved out.Summarizing these results, the following reaction mechanism earlier assumed seemed appropriate even from spectrochemical examinations.P+Q→PQ (reaction between quinone and pyrogen)PQ+C→CPQ (adsorptive removal of PQ by activated carbon)CPQ→CQ+P (liberation of pyrogen)

The Deep-Basined Metate of the Southern California Coast

Deep-basined metates are frequently found in early sites on the southern California coast, but the faces of the accompanying manos usually are only moderately convex. Mano faces examined by the writer never have been sufficiently excurvate to make contact with the grinding surfaces of the deeply ground metates. This presents an interesting problem: how were the manos manipulated on the metates?An examination of specimens from Oak Grove sites 7, 21, and 79 (Rogers, 1929) and the Smithsonian Institution River Basin Surveys’ sites 4SBa477 and 4SBa485 in Santa Barbara County, California, reveals the following associations and characteristics. Slab, shallow-basined, and deep-basined metates are found in association. The first two types exhibit an unbroken grinding area, but specimens of the latter almost invariably have a slight shoulder running at least a part of the way around the basin, the transition between a slightly concave ground area and the deeply ground cavity.

On the so-called Diorite of Little Knott (Cumberland), with further remarks on the Occurrence of Picrites in Wales

In my second note on the hornblende-picrite boulders which are scattered over the neighbourhood of Ty Croes, Anglesey, I briefly noticed a similar rock which occurs in situ at Little Knott in the Lake District, and has been described by the late Mr. Clifton Ward as an exceptional variety of diorite. In the spring of last year I was enabled to visit this district, and had the advantage of the company of Mr. J. Postlethwaite of Keswick, whose local knowledge was of great assistance to me. Little Knott is a slight prominence or shoulder on the crest of Long Side, a spur from the main mass of Skiddaw, where the former begins to fall more sharply down to the lowlands on the north. The picrite is represented on the six-inch map of the Geological Survey as an elongated dyke-like mass, running nearly E. and W. for about 650 yards, and generally about 40 yards wide, the outcrop of which extends from Little Knott across a ravine to a point at about the same elevation on the opposite ridge. The boundary, however, is inferential in a part of this area, as the rock is by no means continuously exposed, no small portion being covered with turf. Long Side consists of Skiddaw Slate ; at one locality on its western slope Graptolites are not rare, and here Mr. Postlethwaite on the occasion of our visit discovered a Lingula . At Little Knott itself the picrite mass, being about its usual width, is bounded