bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective uptake of cholesteryl esters from various classes of lipoproteins by HepG2 cells
Authors: Brissette Louise , Charest Marie-Claude , Falstrault Louise , Lafond Julie , Rhainds David , Tremblay Caroline , Truong To-Quyen
Published: April 2011

Selective uptake of cholesteryl esters (CE) from lipoproteins by cells has been extensively studied with high density lipoproteins (HDL). It is only recently that such a mechanism has been attributed to intermediate and low density lipoproteins (IDL and LDL). Here, we compare the association of proteins and CE from very low density lipoproteins (VLDL), IDL, LDL and HDL3 to HepG2 cells. These lipoproteins were either labelled in proteins with125I or in CE with3H-cholesteryl oleate. We show that, at any lipoprotein concentration, protein association to the cells is significantly smaller for IDL, LDL, and HDL3 than CE association, but not for VLDL. At a concentration of 20 µg lipoprotein/mL, these associations reveal CE-selective uptake in the order of 2-, 4-, and 11-fold for IDL, LDL, and HDL3, respectively. These studies reveal that LDL and HDL3 are good selective donors of CE to HepG2 cells, while IDL is a poor donor and VLDL is not a donor. A significant inverse correlation (r2= 0.973) was found between the total lipid/protein ratios of the four classes of lipoproteins and the extent of CE-selective uptake by HepG2 cells. The fate of3H-CE of the two best CE donors (LDL and HDL3) was followed in HepG2 cells after 3 h of incubation. Cells were shown to hydrolyze approximately 25% of the3H-CE of both lipoproteins. However, when the cells were treated with 100 µM of chloroquine, a lysosomotropic agent, 85 and 40% of3H-CE hydrolysis was lost for LDL and HDL3, respectively. The fate of LDL and HDL3-CE in HepG2 cells deficient in LDL-receptor was found to be the same, indicating that the portion of CE hydrolysis sensitive to chloroquine is not significantly linked to LDL-receptor activity. Thus, in HepG2 cells, the magnitude of CE-selective uptake is inversely correlated with the total lipid/protein ratios of the lipoproteins and CE-selective uptake from the two best CE donors (LDL and HDL3) appears to follow different pathways.Key words: lipoprotein, receptor, HepG2 cell, selective uptake, lipid, cholesterol, binding.
Heat shock-induced alterations in phosphorylation of the largest subunit of RNA polymerase II as revealed by monoclonal antibodies CC-3 and MPM-2
Authors: Lavoie Sébastien B , Albert Alexandra L , Thibodeau Alain , Vincent Michel
Published: April 2011

The phosphorylation of the carboxy-terminal domain of the largest subunit of RNA polymerase II plays an important role in the regulation of transcriptional activity and is also implicated in pre-mRNA processing. Different stresses, such as a heat shock, induce a marked alteration in the phosphorylation of this domain. The expression of stress genes by RNA polymerase II, to the detriment of other genes, could be attributable to such modifications of the phosphorylation sites. Using two phosphodependent antibodies recognizing distinct hyperphosphorylated forms of RNA polymerase II largest subunit, we studied the phosphorylation state of the subunit in different species after heat shocks of varying intensities. One of these antibodies, CC-3, preferentially recognizes the carboxy-terminal domain of the largest subunit under normal conditions, but its reactivity is diminished during stress. In contrast, the other antibody used, MPM-2, demonstrated a strong reactivity after a heat shock in most species studied. Therefore, CC-3 and MPM-2 antibodies discriminate between phosphoisomers that may be functionally different. Our results further indicate that the pattern of phosphorylation of RNA polymerase II in most species varies in response to environmental stress.Key words: RNA polymerase II, heat shock, phosphorylation, CC-3, MPM-2.
The nuclear chronicles: gene transcription and molecular traveling
Authors: Kretz-Remy Carole , Michaud Sébastien , Tanguay Robert M
Published: April 2011

The transfer and processing of an RNA transcript from its locus of transcription on chromatin through the nuclear membrane to its site of translation on cytoplasmic ribosomes is a long and complex journey involving numerous processes and interactions with various macromolecules. These various steps that regulate gene expression were the subject of the 9th Winternational Symposium of the Canadian Society of Biochemistry and Molecular & Cell Biology held at Manoir du Lac Delage, a small resort centre north of Québec City on February 12-15, 1999.Key words: nuclear pore, RNA transport, chromatin, RNA-binding proteins, nucleoporins.
Regulated phosphorylation of the RNA polymerase II C-terminal domain (CTD)
Authors: Bensaude Olivier , Bonnet François , Cassé Céline , Dubois Marie-Françoise , Nguyen Van Trung , Palancade Benoit
Published: April 2011

The largest subunit of RNA polymerase II has an intriguing feature in its carboxyl-terminal domain (CTD) that consists of multiple repeats of an evolutionary conserved motif of seven amino acids. CTD phosphorylation plays a pivotal role in controlling mRNA synthesis and maturation. In exponentially growing cells, the phosphate turnover on the CTD is fast; it is blocked by common inhibitors of transcription, such as 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole and actinomycin D. Transcription-independent changes in CTD phosphorylation are observed at critical developmental stages, such as meiosis and early development.Key words: RNA polymerase II, phosphorylation, transcription inhibitors, cyclin-dependent kinases, development.
Inhibition of retinoic acid-inducible transcription by COUP-TFI in human salivary gland adenocarcinoma cell line HSG
Authors: Kyakumoto Seiko , Ota Minoru , Sato Nobuko
Published: April 2011

Human salivary gland adenocarcinoma cells (HSG) express nuclear receptors, all-trans-retinoic acid (at-RA) receptors (RARs), and retinoid X/9-cis-retinoic acid (9-c-RA) receptors (RXRs). In order to investigate whether the endogenous RARs or RXRs of HSG cells can induce transcription activation, the thymidine kinase promoter (TK)-driven luciferase reporter gene containing the retinoic acid response element (RARE), of RARβ, βRARE2-TK-Luc, was transfected into HSG cells and ligand-dependent transcription activation was examined. Luciferase activity of cell lysate increased by the treatment with either at-RA or 9-c-RA. Co-transfection of RARα and (or) RXRα-expression plasmids with the reporter gene enhanced the luciferase activity, suggesting that endogenous RARs and RXRs work as ligand-dependent transfactors in HSG cells. Reverse transcriptase - polymerase chain reaction analysis revealed that HSG cells express chicken ovalbumin upstream promoter - transcription factor I (COUP-TFI). Co-transfection of COUP-TFI-expression plasmid suppressed the at-RA-induced transcription activation of the reporter gene. Similar results were shown using a chromatin-integrated reporter gene system, using a stably transfected β-RARE2-TK-β-galactosidase (β-Gal) reporter gene. The at-RA-dependent increase in the β-Gal expression was completely inhibited by COUP-TFI. The transfection of antisense oligonucleotide of COUP-TFI squelched the RA-dependent growth inhibition induced by RAR-RXR heterodimers. Conclusively, RARs and RXRs of HSG cells are functional and play roles as transactivators in at-RA-sensitive processes such as the proliferation or differentiation of cells. COUP-TFI very likely regulates these processes by repressing the functions of these transactivators.Key words: retinoic acid receptor, retinoid X receptor, COUP-transcription factor (COUP-TF), retinoic acid response element.
Localization and partial characterization of a molecule found in the plasma membrane of starfish and sea urchin embryos using a novel monoclonal antibody
Authors: Crawford B J , Reimer C L , Pang T
Published: April 2011

A monoclonal antibody, P212, has been developed which reacts against 120 kD and 90 kD proteins, P212 antigens found in the plasma membranes of both starfish and sea urchin embryos. Immunocytochemical studies with colloidal gold tagged P212 showed that the P212 antigens are also found on the inner membranes of several different types of granules and vesicles located in the eggs and cytoplasm of embryonic cells, and in the trans region of the Golgi apparatus. One or both of the P212 antigens are also found in the cortical granules, granules which are exocytosed at fertilization. They are not found on intracellular membrane structures such as the rough endoplasmic reticulum, the nuclear membrane, or a number of deeper granular structures. The P212 antigens are probably located on the membranes of vesicles which are on the exocytosis-endocytosis pathway and may be involved in cell trafficking.
Signal transduction pathways, and nuclear translocation of zinc and metallothionein during differentiation of myoblasts
Authors: Apostolova Margarita D , Ivanova Iordanka A , Cherian M George
Published: April 2011

The changes in subcellular localization of metallothionein during differentiation were studied in two myoblast cell lines, L6 and H9C2. Addition of insulin like growth factor-I or lowering foetal bovine serum to 1% can induce differentiation of myoblasts to myotubes. Metallothionein and zinc were localized mainly in the cytoplasm in myoblasts but were translocated into the nucleus of newly formed myotubes during early differentiation. In fully differentiated myotubes, metallothionein content was decreased with a cytoplasmic localization. Addition of an inhibitor of mitogen-activated protein kinase, PD 98059, did not affect differentiation but blocked nuclear translocation of metallothionein. LY 294092, an inhibitor of PI3 kinase, and rapamycin, an inhibitor of p70S6 serine/threonine kinase, abolished insulin-like growth factor-I induced differentiation of myoblasts, retained metallothionein in the cytoplasm, and decreased metallothionein content. These results demonstrate that the cytoplasmic-nuclear translocation of metallothionein occurs during the early stage of differentiation of myoblasts to myotubes and can be blocked by inhibition of certain signal transduction pathways. The transient nuclear localization of metallothionein and zinc may be related to a high requirement for zinc for metabolic activities during the early stage of differentiation.
Is ATP a substrate for 15-lipoxygenase?
Authors: Kumarathasan Rajkumar , Leenen Frans HH
Published: April 2011

Lipoxygenases catalyze peroxidation of polyunsaturated fatty acids containing the 1-cis, 4-cis pentadiene structure. Linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids are the predominant substrates for this class of enzymes. Effects of 15-lipoxygenase on the hydrolysis of adenosine 5'-triphosphate were investigated in vitro using soybean lipoxygenase and adenosine 5'-[γ-32P]triphosphate. The amount of inorganic phosphate released from adenosine 5'-triphosphate was dependent upon enzyme as well as substrate concentrations, pH, and the duration of incubation. The ATPase activity with a Vmaxvalue of 3.3 μmol·mg protein-1·h-1and a Kmvalue of 5.9 mM was noted in the presence of different concentrations of ATP at pH = 7.4. Phenidone, a lipoxygenase inhibitor, had no effect on this reaction. These findings suggest that soybean lipoxygenase catalyzes the release of inorganic phosphate from ATP primarily via hydrolysis.

Key words: 15-lipoxygenase, adenosine 5'-triphosphate, hydrolysis, phenidone.
THE ANGULAR DISTRIBUTION OF THE RADIATION AT THE INTERFACE OF TWO ADJOINING MEDIA
Authors: Chandrasekhar S.
Published: April 2011

In this paper the results contained in a recent paper by B. Davison entitled "Angular Distribution of Neutrons at the Interface of Two Adjoining Media" are derived by certain elementary methods based on certain simple invariances characterizing the problem.
THE EFFECTS OF PLASTIC DEFORMATION ON MAGNETIC PROPERTIES OF POLYCRYSTALLINE METALS
Authors: Martius Ursula M.
Published: April 2011

Most of the laws of the ferromagnetic behavior of metals and alloys were derived from studies of single crystals. In order to apply these laws to polycrystalline metals the effect of the crystallographic composition of the polycrystalline body has to be taken into account. For this purpose the concept of a "closed flux shell" as a fundamental quality of polycrystalline metal is put forward on the basis of the following trend of thought:One of the most important factors determining the size and arrangement of ferromagnetic domains in a single crystal is the tendency to close the magnetic flux throughout the specimen by a suitable arrangement of these domains. The size of the crystal defines the limits within which the flux can be closed. In a polycrystalline metal, a "crystal" is defined as a region of one crystallographic orientation separated by crystal boundaries from neighboring regions of different orientation. The corresponding unit, as far as ferromagnetic properties are concerned, will be a closed flux shell which may contain many domains but is always a region of closed magnetic flux. Neighboring regions, having different crystallographic orientation, will each also consist of a closed magnetic flux shell. Crystal boundaries are regarded as lattice discontinuities which separate regions of different orientation and at the same time separate different closed flux shells.The consequences of this model and experimental evidence supporting it are discussed. An explanation of the effect of plastic deformation on magnetic properties is suggested by considering the changes in the size of the closed flux shell which will occur during plastic deformation.
STATISTICS OF A LINEAR PARAMAGNETIC MACROMOLECULE
Authors: Opechowski W. , Bryan J. M.
Published: April 2011

The partition function of a linear "macromolecule" composed of N paramagnetic atoms subject to the Ising interaction is calculated for an arbitrary N. From the partition function the expressions for the specific heat and the initial paramagnetic susceptibility are obtained. It is shown on the example of the susceptibility that the procedure, customary in statistical mechanics, which consists in using the asymptotic expressions (N→∞) to describe actual physical systems (N very large, but finite) should be used with some caution in the region of very low temperatures.
ON THE THEORY OF THE HALL EFFECT
Authors: Koppe H. , Bryan J. M.
Published: April 2011

A phenomenological theory of the Hall effect is applied to: (1) the effect of an inhomogenous magnetic field on the Hall effect in thin layers (par. 4, par. 5); (2) the magnetic increase of resistivity under the same conditions (par. 6); (3) the Hall effect in a homogenous magnetic field in inhomogenous layers (par. 7–9). The first paragraphs give a simple kinetic theory.
SCALE MODEL EXPERIMENTS IN ELECTROMAGNETIC METHODS OF GEOPHYSICAL EXPLORATION
Authors: Clark A. R. , Mungal A. G.
Published: April 2011

A method of accurately measuring the phase as well as the amplitude of alternating magnetic fields of small amplitude has been devised and applied to the investigation of the response of conducting bodies placed in an electromagnetic field.The results have indicated how the position, dimensions, and dip of buried conductors may be evaluated.
PREDISSOCIATION AND DISSOCIATION OF THE N2 MOLECULE
Authors: Douglas A. E. , Herzberg G.
Published: April 2011

The predissociation in the upper state of the Lyman–Birge–Hopfield bands of nitrogen has been investigated under high resolution. A clear breaking-off of the fine structure has been found above ν′ = 6, J′ = 13 both in the P and the Q branches. The predissociation limit is at 78,843 ± 50 cm.−1 which is smaller than the well known dissociation limit 97,944 cm.−1 by very nearly the excitation energy of the 2D state of the N atom. This observation eliminates the intermediate value, 8.565 ev., for the dissociation energy of the N2 molecule. A definite decision between the two remaining values, 9.756 and 7.373 ev., cannot yet be made. Acceptance of the former would involve the assumptions that the predissociation in the a1Πg state is caused by the [Formula: see text] state resulting from normal atoms and that this [Formula: see text] state is not purely repulsive. The elimination of the value 8.565 ev. for D(N2) removes the value 7.50 ev. for D(CN) which has been fairly widely accepted.
AN ESTIMATE OF THE RELATIVE HELIUM CONTENT OF THE EARLY-TYPE STARS
Authors: Underhill Anne B.
Published: April 2011

The relative abundance of hydrogen to helium in O-type atmospheres is estimated by a comparison of the computed strength of the HeII line λ4541 with observed values. The line profile of λ4541 in an O9.5 V and in an O5 V model atmosphere is computed when the ratio H: He = 5.67 and when it is 13.33, and the equivalent width of the line derived. Observations of the strength of λ4541 in the spectra of the O9 V star, 10 Lacertae, and the O9.5 star, σ Orionis, are given, and the observed equivalent width of λ4541 in a real stellar atmosphere of spectral type corresponding to the O9.5 V model atmosphere is estimated. A comparison of the observed strength of HeII λ4541 with the computations indicates that the abundance ratio H: He lies in the range 20 to 25, that is, the relative abundance of helium is reduced by a factor of 1/3 to 1/2 from the amounts estimated by several authors by other spectroscopic methods. It is shown that the O9.5 V model atmosphere gives a fair representation of a late O-type main-sequence atmosphere, and that the computations can best be reconciled with observation by reducing the relative abundance of helium to about 4 or 5% by number, the rest of the stellar atmosphere being effectively pure hydrogen. The computations for the O5 model atmosphere are not in agreement with this result, but reasons are given for believing that the O5 model atmosphere does not give a good representation of an early O-type stellar atmosphere, and that consequently the results obtained from this model atmosphere are not of equal weight to those obtained from the O9.5 model atmosphere.
PHYSICAL ASPECTS OF THE CONTRACTION HYPOTHESIS OF OROGENESIS
Authors: Scheidegger Adrian E.
Published: April 2011

Several geophysical arguments important in the theoretical consideration of the contraction hypothesis of orogenesis are analyzed in detail with respect to their physical bases. Specifically, it is shown (a) that a thin surface layer of a sphere will fold in a smaller pattern than a thicker surface layer if the interior shrinks by the same amount; (b) that the speed of cooling of a sphere decreases if some radioactive and hence heat generating material is moved from the surface towards the center (and conversely); and (c) that at the level of no strain of a cooling sphere the temperature–depth curve must be almost straight. Those geological theories in which these considerations are important are indicated.
DESIGN AND USE OF A COINCIDENCE CIRCUIT OF SHORT RESOLVING TIME
Authors: Bell R. E. , Graham R. L. , Petch H. E.
Published: April 2011

A coincidence circuit for use with anthracene or stilbene scintillation counters is described. Its resolving time lies in the 10−9 sec. range, in agreement with theoretical estimates of the minimum possible resolving time with these scintillation counters. Examples are given of the use of the circuit in the measurement of short gamma-ray half-lives and, in conjunction with beta-ray spectrometers, in the determination of the details of radioactive disintegration schemes. The new results given in these examples are as follows:[Formula: see text]
AN ANALYSIS OF THE SELF-ENERGY PROBLEM FOR THE ELECTRON IN QUANTUM ELECTRODYNAMICS
Authors: Daykin P. N.
Published: April 2011

Feynman's S-matrix for the self-energy of the free resting electron is evaluated without the restriction that the virtual photons in the intermediate state have only positive energy. Both the one-electron theory and the hole theory of the positron are treated. It is shown that in the one-electron theory the normally quadratically divergent transverse part of the self-energy vanishes if the photon field is assumed to be symmetric in positive and negative energies. A similar theorem does not hold in the hole theory. A particular type of interaction leads to a vanishing self-energy in one-electron theory. However, this does not solve the self-energy problem, as in this case radiation corrections to scattering would vanish as well. The S-matrix for the self-energy of a bound electron is evaluated in a similar manner. The decay probability for an excited state is calculated as the imaginary part of the self-energy. The correct value is obtained only in hole theory and in interaction with positive energy photons. In the special case in which the external field is a uniform magnetic field, again only hole theory with this same interaction gives the correct value for the anomalous magnetic moment.
DENSITY EFFECTS IN THE RAMAN SPECTRUM OF CARBON DIOXIDE
Authors: Welsh H. L. , Pashler P. E. , Stoicheff B. P.
Published: April 2011

Two Raman tubes, one of quartz and one of glass, capable of withstanding pressures up to 75 and 300 atm. respectively, were used to study density effects in the Raman spectrum of carbon dioxide. The components of the ν1 band show changes in frequency and relative intensity with increasing density. An analysis shows that the frequency changes are due to a lowering of the frequency of 2ν2, in Fermi resonance with ν1, with increasing density. The intensity effect, however, is not completely explained by the change in the sharpness of the resonance. In the high pressure gas and in the liquid faint bands corresponding to the Raman inactive frequencies, ν2 and ν3, are observed. The effect of increasing density on the rotational Raman spectrum can be explained in terms of the broadening of anisotropic scattering by intermolecular forces.
THE ACOUSTICAL FIELD NEAR A CIRCULAR TRANSDUCER
Authors: Guptill E. W. , MacDonald A. D.
Published: April 2011

An approximate solution for the near field of a circular transducer is given. The results indicate that, if a similar transducer is used as a receiver, the measured particle velocity is equal to 1 + (2.70/(ka)2) times the plane wave velocity, where ka is the number of wave lengths in the perimeter of the transducer.
THE DYNAMICAL THEORY OF MAGNETIC MONOPOLES
Authors: Shanmugadhasan S.
Published: April 2011

The theory of electric charges and magnetic monopoles has been set up by Dirac by expressing the electromagnetic field tensor in terms of one four-potential and of the variables describing the strings attached to each magnetic mono-pole. In this reformulation of Dirac's theory the field tensor is expressed in terms of two four-potentials, one corresponding to charges and the other to monopoles, and the action principle for the equations of motion is set up in terms of the two four-potentials and of the tensors dual to them. Thus there is formal symmetry as far as is possible in the treatment of the charges and the monopoles. Also the mathematics is direct and neat. Though the physical content is the same as that of Dirac, a natural generalization of the Fermi form of electrodynamics subject to the restriction that the same particle cannot have both charge and monopole is obtained here.
THE INTENSITIES OF HARMONIC BANDS OF THE HD MOLECULE
Authors: Wu Ta-You
Published: April 2011

The approximate intensity ratio 1:3 or 1:4 for the 4–0 and 3–0 vibrational bands of HD observed by Herzberg seems rather high on the basis of the usual anharmonicity considerations. To understand this, the problem is discussed qualitatively on the basis of classical mechanics. A quantum mechanical calculation of the intensities of various vibrational transitions is made by an extension of the perturbation theory treatment by Wick for the fundamental band. The relative intensities of the various vibrational bands are finally expressed as a function of the ratio ξ = a(0; 1)/a(0; 0) of the matrix elements, with respect to the vibrational states 1 and 0, of a quantity closely resembling the polarizability of the molecule. For the 4–0 and 3−0 bands, the intensity ratio I(4–0)/I(3–0) does not depend very much on the ratio ξ and has the value ~0.27, in agreement with the approximate observed value. The case of the molecular ion HD+ is also briefly discussed.
RADIAL MATRIX ELEMENT FOR THE QUADRUPOLE TRANSITION WITH THE MORSE POTENTIAL
Authors: Buckmaster H. A.
Published: April 2011

A general formula for the radial part of the matrix element for the quadrupole transition with the Morse potential is derived using standard methods of analysis. The same methods can also be used to derive an expression for the radial part of the dipole transition matrix element.
DESIGN AND OPERATION OF A 'MEAN DEVIATION METER'
Authors: Greenberg L. H. , Happ W. W.
Published: April 2011

An instrument was constructed and calibrated to measure the mean deviation of the counting rate from a series of pulses that are not uniformly spaced. Two resistance–capacitance 'memory' circuits measure the instantaneous and the average counting rates. A rectifier bridge circuit is used to compute the relative deviation. Over a large part of the range the response is linear and reproducible within 5% for full scale deflection. The instrument is used in conjunction with the counting of radioactive radiations; other uses are discussed.
A SIMPLE ACTIVATION FOR BeCu MULTIPLIERS
Authors: Osborne F. J. Fitz
Published: April 2011

A consideration of previous methods used in activating BeCu electron multiplier plates has resulted in the development of a simple inert gas treatment using a minimum of apparatus and resulting in a total multiplication factor comparable to that obtained by other treatments.
DIELECTRIC PROPERTIES OF SOME SOLID PROTEINS AT WAVE LENGTHS 1.7 METERS AND 3.2 CENTIMETERS
Authors: Laird Elizabeth R.
Published: April 2011

Measurements have been made of the dielectric constant and the attenuation coefficient of casein, egg albumin, lactalbumin, and zein, in powder form at λ 1.7 meters and λ 3.2 cm., and of horn keratin, at stages in drying, at λ 3.2 cm. The Böttcher formula was used to reduce the observed value of the dielectric constant of a powder to that of the solid. It was tested on cane sugar in granulated and powder forms with satisfactory results. The attenuation coefficients of the powders were found to be roughly inversely proportional to the wave lengths. The values at λ 3.2 cm. were in the range 0.03 to 0.04 cm.−1 and did not suggest resonance absorption. The dielectric constants found for the albumins at both wave lengths were close to 3.6. [Formula: see text] for zein increased from 3.7 at λ 3.2 cm. to 4.0 at λ1.7 meters, for casein from 4.0 to a possible 4.2. [Formula: see text] for keratin increased from 3.6 when dry to 4.4 with 6.5% moisture, and α increased from 0.05 to 0.14 cm.−1
THE ENERGY SPECTRUM OF THE X RAYS FROM A 70-MEV. SYNCHROTRON
Authors: McDiarmid I. B.
Published: April 2011

The spectrum of the X rays produced in the forward direction by 70-Mev. electrons striking a very thick target has been measured. The scattering method has been used to determine the energies of about 650 electron pairs produced by the X rays in G-5 emulsions and from this the spectrum has been deduced. The number of photons found below 25 Mev. is considerably less than that expected from the Bethe–Heitler–Schiff theory. No satisfactory explanation of this has been found but the measured spectrum is in agreement with "yield" measurements done iii this laboratory.
PHOTONEUTRONS IN A HEAVY WATER PILE
Authors: Johns M. W. , Sargent B. W.
Published: April 2011

Decay curves of the neutron intensity in the low power heavy water pile (ZEEP) at Chalk River as a function of time from shutdown with cadmium rods were obtained with three proportional counters of different sensitivities. The range of counting rates spanned, including operation at 50 w., was 8 × 105. The durations of steady operation before shutdown were 10, 50, and 230 min. The mean lifetimes and absolute yields of delayed and photoneutron groups were found by analyzing each decay curve into a sum of decreasing exponentials and using the theory of pile kinetics. The yields were corrected to infinite irradiation time. These results are compared with data obtained by others. The comparison shows that the energetic γ-rays of fission products which produce photoneutrons in the heavy water are absorbed to the extent of about 26% in the heavy water and 74% in the uranium rods. A table of recommended mean lifetimes and absolute yields of delayed and photoneutrons is given for use in the kinetics of heavy water piles such as ZEEP. Some quantitative data on the effects of the control plates and shutoff rods are included.
ON THE CONCEPT OF FIELD QUANTIZATION
Authors: Kaempffer F. A.
Published: April 2011

Attempts by Takabayasi and Kaempffer at an entirely different method of field quantization, starting from the hydrodynamic formulation of classical field theories rather than from their formulation in terms of wave equations, are examined in the light of Ziman's recent successful approach towards the quantum hydrodynamical problem. It is pointed out that the energetic impossibility of a roton spectrum in an ideal continuum fluid, as shown by Ziman, makes it necessary to introduce into the theory a fundamental length, which acts as high frequency cut-off, and which may be interpreted as representing a substructure of the medium in which elementary particles may appear as excitations of the motion. Takabayasi's generalized hydrodynamic formulation of the nonrelativistic Schroedinger equation is treated as an example, and it is shown that the fundamental length must be of the order h/mc, if the particle corresponding to the single roton excitation of the Takabayasi field is to have the mass m.
INDUCED INFRARED ABSORPTION IN HYDROGEN AND HYDROGEN - FOREIGN GAS MIXTURES AT PRESSURES UP TO 1500 ATMOSPHERES
Authors: Chisholm D. A. , Welsh H. L.
Published: April 2011

The pressure-induced fundamental infrared absorption band of hydrogen has been investigated in the pure gas and in hydrogen–helium, hydrogen–nitrogen, and hydrogen–argon mixtures for gas pressures up to 1500 atm. and temperatures in the range 80°–376°K. At the higher densities the rate of increase of the integrated absorption coefficient with density is anomalously large; this effect is interpreted in terms of finite molecular volumes. The Q branch has been shown to consist of three components QP, Qq, and QR. The separation of the maxima in the low- and high-frequency components, QP and QR, depends on the perturbing gas and increases linearly with its density; the separation and relative intensities of the components are also strongly dependent on the temperature. It is proposed that this splitting of the Q branch is caused by the participation of the relative kinetic energy of the colliding molecules in the absorption process for collisions in the region of overlap forces. The Qq component and the S lines show no splitting and are probably produced by collisions in the region of quadrupole interaction.
THE λ4050 BANDS OF THE C313 MOLECULE
Authors: Clusius K. , Douglas A. E.
Published: April 2011

The λ4050 bands, excited with the pure C13 isotope, have been photographed under high resolution. The lines of the strongest band show a 3: 1 intensity alternation. The B values of the C13 band are in the ratio 12: 13 to the B values of the corresponding C12 band. These isotope effects are interpreted as giving very good evidence that the λ4050 band is emitted by a triatomic carbon molecule C3.
ON THE THEORY OF AN ANTENNA WITH AN INFINITE CORNER REFLECTOR
Authors: Wait James R.
Published: April 2011

Some comments are made concerning the theory of a dipole radiator inside a corner or "V" reflector of infinite extent. A straightforward solution is obtained for the resultant fields anywhere within the angle subtended by the V. The result is discussed and compared with Moullin's theoretical treatment for the filament source.
SEARCH FOR A POSSIBLE ERROR IN THE MEASURED HALF LIFE OF Au198
Authors: Yaffe L. , Bell R. E.
Published: April 2011

The half life of Au198 has been measured using a quartz fiber electroscope, with extreme precautions against errors due to the presence of Au199 in the source. The result obtained, 2.699 ± 0.003 days, shows that other recent determinations of the Au198 half life do not suffer an appreciable error from this cause.
DEPENDENCE OF INTEGRATED DURATION OF METEOR ECHOES ON WAVELENGTH AND SENSITIVITY
Authors: McKinley D. W. R.
Published: April 2011

The reflecting properties of short-duration and long-duration echoes from meteor trails are examined. For short-duration echoes only, the observed relation between relative numbers and durations of meteor echoes is independent of wavelength, the time of day, or the presence of a strong shower. Integrated duration times are determined from back-scatter experiments on 9.22 m., 5.35 m., and 2.83 m., and are found to vary with the 3.5th power of the wavelength, for either short- or long-duration echoes. The integrated echo power depends on the 6th power of the wavelength. The effect of changing the equipment sensitivity is considered. The data from the back-scatter observations are used to predict the integrated duration times in the forward-scatter case, and in particular, it is shown that the results of the Cedar Rapids – Sterling very-high-frequency experiment may be explained by meteoric reflections.
ON THE EVALUATION OF CERTAIN LATTICE SERIES
Authors: Roy S. K.
Published: April 2011

Lattice series of the Madelung type are at best conditionally convergent; the values of such series, therefore, depend on the method of summation. A criterion is indicated for the choice of a method of summation leading to a physically significant value consistent with the problem in which such a series occurs. Evjen's method of grouping the terms of the series into particular units is discussed in detail for the CsCl type of lattice. It is found that in this case, his method fails to yield directly the unique physically significant value. An alternative method is proposed which leads at once to the unique value and is applicable to any series of the Madelung type.
NEW MEASUREMENTS ON THE AlΠ ↔ X1Σ BAND SYSTEM OF AlH
Authors: Zeeman P. B. , Ritter G. J.
Published: April 2011

The AlH band system at 4241 Å was produced in a large King Furnace and the bands were photographed in emission and absorption in the second and third orders of a 21 ft. concave grating. The vibrational and rotational constants were newly determined with improved accuracy.
GAMMA RADIATION FROM THE PROTON BOMBARDMENT OF OXYGEN
Authors: Warren J. B. , Laurie K. A. , James D. B. , Erdman K. L.
Published: April 2011

The nuclear gamma radiation following the non-resonant capture of a proton in O16 has been studied with protons of energies, from 800 kev. to 2.1 Mev. and found to consist of three components. The main transition goes, via a gamma ray of energy that varies with proton bombarding energy, to the [Formula: see text] state of F17. This state, 487 kev. above the ground state, radiates directly to the ground state. In addition there is a weaker direct radiative transition from the capture configuration to the ground state. At energies above Ep = 1.8 Mev. oxide targets bombarded with protons give rise to a radiation of 873 kev. attributed to the presence of the O17 isotope via the reaction O17(p, p′)O17*, the radiation corresponding to the transition from the first excited state of O17 to the ground state.
THE PHOTONEUTRON AND PHOTOPROTON CROSS SECTIONS OF SILICON AND MAGNESIUM
Authors: Katz L. , Haslam R. N. H. , Goldemberg J. , Taylor J. G. V.
Published: April 2011

The (γ, n) and (γ, p) cross sections were measured as a function of photon energy in a number of isotopes. They were found to have the resonance shapes characteristic of photonuclear reaction for which the pertinent data are summarized in the table.[Formula: see text]In view of the fact that in each isotope the threshold for the (γ, p) reaction is higher than that for the (γ, n) reaction it is surprising to find the maximum (γ, p) cross section to be at least equal to the maximum (γ, n) cross section, while peaking at about 6 Mev. higher energy. These results are discussed in some detail.
THE HYPERFINE STRUCTURE OF MERCURY EXTRACTED FROM NEUTRON-IRRADIATED GOLD
Authors: Bedford R. E. , Crooker A. M.
Published: April 2011

The h.f.s. of suitable lines excited in mercury extracted from several gold samples in different neutron fluxes has been photographed with a Fabry-Perot interferometer. As well as the strong lines due to Hg198, weak lines are also observed for Hg199 owing to the Au198 capturing a neutron before the β-decay. The branching ratio is[Formula: see text]Using the measured ratio of Hg199 to Hg198, τ = 2.69 days, and the neutron fluxes we have determined for the Au198 capture cross section, σ = (1.78 ± 0.10) × 104 barns.
MASSES OF NUCLEI IN ISOBARIC SEQUENCES
Authors: Kumar Kailash , Preston M. A.
Published: April 2011

The semiempirical mass formula is known to give a rough fit to the general trend of atomic masses. A detailed correlation to within 0.5 Mev. or less is attempted between observed atomic mass-differences and the predictions of a semiempirical liquid drop formula generalized to include terms which depend on angular momentum in the way suggested by the nuclear shell model. For fixed A, it is found that, allowing for these "spin terms", the Z-dependence is parabolic. The variations of the different parameters with A and with shell changes are studied. It is found that, when close agreement with experimental values of mass is required, certain "constants" of the liquid drop formula are in fact quite dependent on A. This is interpreted to mean that the A- or Z-dependence of the formula is incomplete. Nevertheless, an empirical method of extrapolating unknown masses is suggested.
LONG DISTANCE V.H.F. FIELDS: II. REFRACTIVITY PROFILES CONTAINING "SHARP LAYERS"
Authors: Northover F. H.
Published: April 2011

In this part the general solution developed in Part I is applied to the case in which the refractivity profile contains sharp layers (i.e. local regions where μ and dμ/dh change very rapidly compared with their rate of variation in a "standard" type atmosphere). It is found that such layers, when well developed, can cause distant fields of the order of magnitude of those which have been observed, but present experimental evidence seems to indicate that scattering from atmospheric turbulence is usually the important factor. An attempt is made to work out a physical interpretation of the field-formation below the elevated layer.
THE BETHE–SALPETER EQUATION FOR MANY-BODY SYSTEMS
Authors: Robinson R. O. A.
Published: April 2011

The mathematical technicalities involved in reducing the Bethe–Salpeter equation to the Schrodinger form of a wave equation are simplified by means of a formal modification of the interaction process for systems of many particles. This also makes it possible to carry out the reduction in a unique manner. The consequences of the modification are clearly explained, and it is shown that for atomic systems numerical results remain unchanged to order α2. There would seem to be some grounds for believing that numerical results remain unchanged to all orders, but no formal proof of this has been achieved.
SOME CONSIDERATIONS REGARDING THE PRINCIPLE OF PHASE INVARIANCE
Authors: Kaempffer F. A.
Published: April 2011

Taking the view that "particles" are in fact excitations of the motion of an all-pervading medium (or "ether"), it is shown that the conservation laws characterizing the ether, which are different from the well-known laws of conservation of energy and momentum, flow from a single principle, the principle of phase invariance, provided a complex field is used to describe the ether. There are at least two different self-consistent types of Lorentz-invariant ether theories which satisfy the principle of phase invariance.
THE THERMAL NEUTRON CAPTURE CROSS SECTION OF AU198 AND THE HALF-LIFE OF AU199
Authors: Bell R. E. , Graham R. L. , Yaffe L.
Published: April 2011

The thermal neutron capture cross section of radioactive Au198 has been measured by the activation method as 26,000 ± 1200 barns, assuming 99 barns for the thermal neutron cross section of Au197. Metallic Au197 was bombarded in fluxes up to 9 × 1013 thermal neutrons cm.−2 sec.−1 to produce a mixture of Au198 and Au199 by the successive neutron capture reactions Au197(n, γ)Au198(n, γ)Au199. The ratio of the Au199 activity to Au198 activity so produced yields σc(Au197). In a preliminary experiment, the half-life of Au199 was measured as 3.148 ± 0.010 days.
THE EFFECT OF A RANDOM NOISE BACKGROUND UPON THE DETECTION OF A SINUSOIDAL SIGNAL
Authors: Heaps H. S.
Published: April 2011

A sinusoidal signal is examined after reception upon a noise background of random phase and power distributed statistically according to a Rayleigh law. An expression is obtained for the probability distribution of the ratio of the power of the signal plus noise at any instant to the power of the noise which would be received at that instant in the absence of the signal. The corresponding result is given for the ratio of the averages over several observations. The equations contain as a parameter the ratio of the signal power to the mean noise power. When each observed value of the power is the average over a small time interval the formulae are applicable provided the noise and the signal have the same frequency. A similar analysis is presented to deal with the case in which the noise and the signal have different frequencies and in which each observation is the average over a small time interval. Comparison with the results of a previous paper, in which the signal was assumed to have a Rayleigh distribution in phase and power, indicates the effect of extreme fluctuation of an originally sinusoidal signal upon its resultant with a random noise background.
DETECTION OF ELECTRONS IN THE VERY LOW ENERGY RANGE
Authors: Giroux G. , Geoffrion C.
Published: April 2011

not available
SCATTERING OF AN ELECTRON BY AN ATOM AND REARRANGEMENT COLLISIONS
Authors: Wu Ta-You
Published: April 2011

For the problem of the scattering of an electron by a hydrogen atom, the complete equivalence is shown of the treatment of Trainor and Wu based on symmetry considerations and that of Altshuler giving a direct proof of the method of Mott and Massey. A generalization of the treatment of Altshuler to scattering processes involving non-identical particles or other rearrangement collisions is made. Also, the usual treatment involving matrix elements for transitions between states belonging to two different Hamiltonians is discussed and justified. Finally, the recent treatment by Dirac of rearrangement collisions is discussed, and it is shown that a correct formulation of the method and interpretation of the result give exactly the same result as in the usual treatment.
PATTERNS OF STUB ANTENNAS ON CYLINDRICAL STRUCTURES
Authors: Wait James R. , Okashimo K.
Published: April 2011

Theoretical radiation patterns are presented for radial electric dipoles located on an isolated circular cylinder, and a cylindrically tipped half-plane. These cylindrical structures are considered to be of infinite length and of perfect conductivity. The computed patterns for the isolated cylinder compare well with the experimental results reported by Bain.
ON THE THEORY OF A COAXIAL TRANSMISSION LINE CONSISTING OF ELLIPTIC CONDUCTORS
Authors: Wong J. Y.
Published: April 2011

A coaxial transmission line consisting of conductors of elliptic cross-section is treated as a boundary-value problem. Using elliptic-cylinder wave functions, a formula is derived for the propagation constant of the allowed symmetric modes of propagation. A condition for the generation of the higher-order modes is established in terms of the physical parameters. The analysis is restricted to the case where both the inner and outer conductors are confocal. A configuration of practical interest follows for the limiting case of the inner conductor consisting of a flat strip. The resulting structure can be regarded as constituting a form of shielded "strip" transmission line. The analysis may be used to provide an approximate theory for the "rectangular" coaxial line.
PARAMAGNETISM OF THE γ PHASE IN COPPER MANGANESE ALLOYS
Authors: Myers H. P.
Published: April 2011

Measurements of the paramagnetic susceptibility and its variation with temperature were made on a series of copper manganese alloys having compositions from 10 to 90 atomic per cent manganese. The measurements were confined to the temperature regions where the face centered cubic γ phase is known to be stable. The results show that alloys containing <25 atomic per cent manganese present a Curie–Weiss dependence of susceptibility on temperature, in agreement with earlier work. For compositions between 30 and 40 atomic per cent manganese the 1/χ vs. T graph is linear at high temperatures but becomes increasingly curved at lower temperatures, the curvature being concave to the temperature axis. Alloys containing more than 60 atomic per cent manganese show a linear variation of 1/χ with temperature but the change in χ, both with temperature and with composition, is slight. Alloys with 70 and 80 atomic per cent manganese show minima in the susceptibility at 900° and 950 °C. respectively. An alloy with 90 atomic per cent manganese showed a continuous increase of susceptibility with temperature.
ABSORPTION SPECTRA OF BENZENE AND BENZENE-d6 IN THE VACUUM ULTRAVIOLET
Authors: Wilkinson P. G.
Published: April 2011

The absorption spectra of benzene and benzene-d6 have been photographed from 1300 Å to 1850 Å in the first order of a 21-ft. normal incidence vacuum spectrograph. The band analysis resulted in the identification of four Rydberg series (over one hundred vibrational bands) in each molecule, converging to ionization potentials of 9.247 ev. (benzene) and 9.251 ev. (benzene-d6). Progressions of the ν2, ν18, and ν20 vibrations are associated with most of the 31 observed Rydberg transitions, and vibrational constants are tabulated for each. The strong intensity and the unusual length of the upper state ν18 (e2g) progression in comparison with the ν2(a1g) progression are interpreted in terms of the Jahn–Teller theorem, and it is concluded that the stable equilibrium nuclear configuration in the Rydberg states is of D2h symmetry.
PHOTOCONDUCTIVITY IN INDIUM-DOPED SILICON
Authors: Blakemore J. S.
Published: April 2011

Impurity photoconductivity has been studied in silicon doped with indium, at various temperatures in the range 63–90°K. The long wave limit of spectral response and analysis of the bulk electrical properties both confirm an ionization energy of 0.16 ev. for the indium centers. An apparent variation of quantum efficiency in the range 5–8 μ is noted and discussed. The magnitude of the photoconductive response suggests an effective recombination coefficient of about 10−6 cm.3/sec. at 90°K., rising steeply on further cooling. This demands a much more active recombination mechanism than present theories provide.
NEUTRON YIELDS FROM ACTINIDE–BERYLLIUM ALLOYS
Authors: Runnalls O. J. C. , Boucher R. R.
Published: April 2011

The neutron yields from the reaction Be9(α, n)C12 have been measured for several actinide–beryllium alloys. The values for the beryllium thick target neutron yield, derived from the measurements on alloys containing Pu239, Am241, and Cm242, are 60 ± 2, 74 ± 2, and 112 ± 3 neutrons per million alphas, respectively, when based on the Chalk River standard Ra226-α-Be source. The dependence of the thick target yield, nmax, on the alpha-particle energy, E, is described by the empirical formula nmax = 0.152 E3.65 neutrons per million alphas. The yields for Ra-α-Be and Ac227-α-Be, calculated from the latter expression, are in reasonable agreement with the best observed yields from powder-compacted sources. For Po-α-Be, the calculated thick target yield of 67 neutrons per million alphas lies within the limits of error of the yield observed by several earlier workers.