bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorocarbon film as cathode protective coating in organic light-emitting devices
Authors: Sun H. Y. , Lau K. M. , Lau K. C. , Chan M. Y. , Fung M. K. , Lee C. S. , Lee S. T.
Published: May 2006

The present work demonstrates the use of fluorocarbon (CFx) film as a cathode protective layer to enhance the stability of organic light-emitting devices (OLEDs). Devices with the CFx cathode protective layer showed a threefold increase in operational lifetime, about 10000h, comparing to those without the CFx layer. Growth of dark spots was significantly suppressed. The superior moisture-resistant capability of the CFx is attributed to its hydrophobic nature and low moisture permeation. As most OLED production lines are already equipped with CFx deposition facilities, the present cathode protective coating can be easily adopted for further stability enhancement without additional capital investment.
Simultaneous measurements of conductivity and magnetism by using microprobes and electron holography
Authors: Murakami Y. , Kawamoto N. , Shindo D. , Ishikawa I. , Deguchi S. , Yamazaki K. , Inoue M. , Kondo Y. , Suganuma K.
Published: May 2006

This study demonstrates a transmission electron microscopy based system that enables simultaneous measurements of conductivity and magnetism in a nanoscale area. A double-probe piezodriving holder is developed in order to determine the conductivity in any part of a thin-foil specimen. The conductivity measurement can be combined with electron holography, which can be used to obtain a magnetic flux map of the same area. This system can be applied extensively for the research and development of electronic and/or magnetic materials.
Optical limiting properties of metal nanowires
Authors: Pan Hui , Chen Weizhe , Feng Yuan Ping , Ji Wei , Lin Jianyi
Published: May 2006

Metal (Cu, Co, Ni, Pd, Pt, and Ag) nanowires (MNWs) have been produced using anodic aluminum oxide as template. The grown MNWs are characterized by scanning electron microscopy, x-ray diffraction, transmission electron microscopy, and electron diffraction. The optical limiting properties of the MNWs are also studied and results obtained at 532 and 1064nm indicate that MNWs have broadband optical limiting capability and the optical limiting performances of some MNWs are comparable to or better than that of carbon nanotubes. It was found that the nonlinear response of MNWs is dominated by nonlinear scattering.
The value of nest boxes in the research and management of Australian hollow-using arboreal marsupials
Authors: Beyer Georgia L. , Goldingay Ross L.
Published: May 2006

Nest boxes have been recognised as research and management tools for arboreal marsupials in Australia for over 20 years. We review the published literature with the aim of describing the scope of studies conducted in Australia thus far and providing guidance to future research. We recognise three types of application in research: (1) detection of species, (2) study of a species’ ecology, and (3) investigation of box designs preferred by different species. Several species of arboreal marsupial may be detected more readily in nest boxes than by conventional survey techniques, allowing description of key aspects of their ecology; e.g. feathertail glider (Acrobates pygmaeus), eastern pygmy possum (Cercartetus nanus) and brush-tailed phascogale (Phascogale tapoatafa). Identifying the most favoured nest-box design for any species has implications for detection and management uses of nest boxes. More research is needed but preliminary findings suggest that species prefer narrow entrance holes, while height of the nest box above 3 m may be inconsequential. We recognise three types of management application: (1) species introduction, (2) support of populations of endangered species, and (3) strategic placement such as to enhance habitat connectivity. Currently there have been few attempts to use nest boxes to manage arboreal marsupials but further research is needed to realise their potential as a management tool.
Understanding bistability in complex enzyme-driven reaction networks
Authors: Craciun Gheorghe , Tang Yangzhong , Feinberg Martin
Published: May 2006

Much attention has been paid recently to bistability and switch-like behavior that might be resident in important biochemical reaction networks. There is, in fact, a great deal of subtlety in the relationship between the structure of a reaction network and its capacity to engender bistability. In common physicochemical settings, large classes of extremely complex networks, taken with mass action kinetics, cannot give rise to bistability no matter what values the rate constants take. On the other hand, bistable behavior can be induced in those same settings by certain very simple and classical mass action mechanisms for enzyme catalysis of a single overall reaction. We present a theorem that distinguishes between those mass action networks that might support bistable behavior and those that cannot. Moreover, we indicate how switch-like behavior results from a well-studied mechanism for the action of human dihydrofolate reductase, an important anti-cancer target.
THE TRANSCRIBING STRANDS OF BACILLUS SUBTILIS DNA FOR RIBOSOMAL AND TRANSFER RNA
Authors: Oishi M.
Published: May 2006

H
3
-labeled purified 16
S
and 23
S
ribosomal RNA's and transfer RNA's were found to hybridize exclusively with the H strand of the separated complementary strands of
B. subtilis
DNA. These results indicate that these RNA's are transcribed
in vivo
from a strand with a composition similar to that from which messenger RNA's are copied and presumably by the same mechanism.
ON CLOSED EXTENSIONS OF FUNCTIONS
Authors: Dickman R. F.
Published: May 2006

G. T. Whyburn has shown that every mapping (by a mapping we will always mean a continuous function) of a topological space into a Hausdorff space is the restriction of a compact mapping with the same range (
Trans. Am. Math. Soc.
, 74, 344-350 (1953)). H. Bauer has proved that every mapping between locally compact Hausdorff spaces can be extended in a topologically unique manner to a compact mapping on a locally compact Hausdorff space with the same range (
Math. Ann.
, 138, 398-427 (1959)). When the range and domain of a mapping are locally compact Hausdorff spaces, Whyburn's and Bauer's extensions are topologically equivalent. It is well known that not every compact mapping is a closed mapping; however, Whyburn has shown that every closed
function
with compact point inverses is a compact function (these PROCEEDINGS, 54, 688-692 (1965)). The principal aim of this paper is to prove that every function (respectively, mapping) from one topological space to another can be extended in a topologically unique manner to a closed and compact function (respectively, mapping) with the same range.
ON THE MECHANISM OF RIBONUCLEASE ACTION
Authors: Usher D. A.
Published: May 2006

All the suggestions that have been made for the mechanism of action of ribonuclease can be classified into one or another of two classes, depending on the geometry of the displacement in the first step. Studies of related model compounds indicate that one of these two classes should include as a part of the mechanism a pentacoordinate intermediate, which undergoes pseudorotation before product can be formed. It is unlikely that the pseudorotation would be rate-limiting in the reaction of the normal substrate.
TWO KINDS OF THETA CONSTANTS AND PERIOD RELATIONS ON A RIEMANN SURFACE
Authors: Farkas H. M. , Rauch Harry E.
Published: May 2006

It was recognized in Riemann's work more than one hundred years ago and proved recently by Rauch (cf.
Bull. Am. Math. Soc.
, 71, 1-39 (1965) that the
g
(
g
+ 1)/2 unnormalized periods of the normal differentials of first kind on a compact Riemann surface
S
of genus
g
≥ 2 with respect to a canonical homology basis are holomorphic functions of 3
g
- 3 complex variables, “the” moduli, which parametrize the space of Riemann surfaces near
S
and, hence, that there are (
g
- 2)(
g
- 3)/2 holomorphic relations among those periods. Eighty years ago, Schottky exhibited the one relation for
g
= 4 as the vanishing of an explicit homogeneous polynomial in the Riemann theta constants. Sixty years ago, Schottky and Jung conjectured a result which implies Schottky's earlier one and some generalizations for higher genera.

Here, we formulate Schottky and Jung's conjecture precisely and, on the basis of a recent result of Farkas (these PROCEEDINGS, 62, 320 (1969)), prove it. We then derive Schottky's result (we believe for the first time correctly) and exhibit a typical relation of this kind for
g
= 5 (we can do this for any genus). We do not prove that
our
relations imply
all
relations, but there are some indications that they do.
A MUTANT OF
Escherichia coli
PERMITTING REPLICATION OF TWO F FACTORS
Authors: Maas W. K. , Goldschmidt A. D.
Published: May 2006

Control mechanisms of replication of bacterial genetic elements are poorly understood at present. We have studied one such mechanism involving replication of the F factor in
Escherichia coli
. The F factor can replicate either autonomously in F
+
or F′ strains, or as an integral part of the chromosome in Hfr strains. We have shown that presence of either an integrated F factor or a free F factor prevents replication of a second free F factor. Two integrated F factors can replicate in the same cell.

The present experiments show that when a F′lac element was transferred by mating into an Hfr strain, it had to become integrated into the chromosome in order to persist. With a recombination-deficient (
recA
) Hfr strain as recipient, the frequency of F′lac integration was greatly reduced. This permitted us to isolate a mutant Hfr strain in which the F′lac element was able to replicate autonomously. The mutation has most likely occurred in the integrated F factor itself. Availability of this new
recA
mutant Hfr strain facilitates genetic analysis of the F factor, since in
recA
+
Hfr strains frequent integration of a free F factor into the chromosome obscures recognition of complementation and recombination between two free F factors.
THE DOMINANCE OF STREPTOMYCIN SENSITIVITY RE-EXAMINED
Authors: Breckenridge Lee , Gorini Luigi
Published: May 2006

Several aspects of the
strA
phenotype were studied in strains of
Escherichia coli
diploid in the
strA
chromosomal region. It was found that alleles causing different levels of interference with amber suppression can complement each other, the less restrictive effects being predominant. The sensitive
strA
+
allele determines two responses to streptomycin: a dominant effect consisting of a sudden, complete, but reversible inhibition of growth, and a recessive effect manifested as cell killing. Both restriction of suppression and inhibition of growth reflect ribosomal involvement in translation.
THE EFFECT OF RANDOM VARIATIONS OF DIFFERENT TYPES ON POPULATION GROWTH
Authors: Levins R.
Published: May 2006

The probability distributions of population size are derived for populations living in randomly varying environments for both density-dependent and density-independent population growth. The effects of random variation in the rate of increase, the carrying capacity, and sampling variation in numbers are examined.
NEGATIVE COOPERATIVITY IN REGULATORY ENZYMES
Authors: Levitzki Alexander , Koshland D. E.
Published: May 2006

Negative cooperativity has been observed in CTP synthetase, an allosteric enzyme which contains a regulatory site. Thus, the same enzyme exhibits negative cooperativity for GTP (an effector) and glutamine (a substrate) and positive cooperativity for ATP and UTP (both substrates). In the process of the delineation of these phenomena, diagnostic procedures for negative cooperativity were developed. Application of these procedures to other enzymes indicates that negative cooperativity is a characteristic of many of them. These findings add strong support for the sequential model of subunit interactions which postulates that ligand-induced conformational changes are responsible for regulatory and cooperative phenomena in enzymes.
EVIDENCE FOR CONTROL OF THE RATE OF NUCLEAR DNA SYNTHESIS BY THE NUCLEAR MEMBRANE IN EUKARYOTIC CELLS
Authors: Alfert Max , Das Nirmal K.
Published: May 2006

Rates of DNA synthesis in root tip cells of diploid and autotetraploid snapdragon (
Antirrhinum majus
) seedlings and in diploid and tetraploid (mononucleate and bidiploid-nucleate) regenerating mouse-liver cells have been studied. The increase in this rate in the tetraploid cells is closely correlated with the increase in nuclear surface area, but not with the nuclear volume; this suggests a possible control of the rate of DNA synthesis by the nuclear membrane.
A NOVEL ACTION OF INSULIN ON PHOSPHOPROTEIN FORMATION BY MAMMARY GLAND EXPLANTS
Authors: Voytovich Anthony E. , Owens Ida S. , Topper Yale J.
Published: May 2006

Studies on the induction of casein synthesis in competent daughter cells formed in mammary gland explants have revealed a new action of insulin. Treatment with prolactin, in the absence of insulin, is responsible for the formation of some polypeptides which are destined to become phosphoproteins, or for the formation of a unique protein-kinase, or both. In any case, insulin is required for participation of the prolactin-induced factor(s) in a protein-kinase reaction.
DEPENDENCE OF THE KINETICS OF SINGLET-SINGLET ENERGY TRANSFER ON SPECTRAL OVERLAP
Authors: Haugland Richard P. , Yguerabide Juan , Stryer Lubert
Published: May 2006

Electronic excitation energy can be transferred between chromophores separated by distances of the order of 30 Å. Förster proposed that the transfer occurs by a dipole-dipole resonance interaction which depends on certain spectroscopic and geometric properties of the donor-acceptor pair. His prediction that the rate of transfer depends on the inverse sixth power of the distance between the chromophores was verified previously. In this work, we tested a second prediction of Förster's theory, namely, that the transfer rate is proportional to
J
, the magnitude of the overlap between the emission spectrum of the energy donor and the absorption spectrum of the energy acceptor.

The energy donor was an N-methylindole moiety, and the acceptor was a ketone. These chromophores were fused to a rigid steroid that separated them by 10.2 Å. Rate constants for singlet-singlet energy transfer in this system were obtained by nanosecond flash spectroscopy.
J
was varied over a 40-fold range simply by altering the solvent. We found that the transfer rate is proportional to
J
, as predicted by Förster's theory. The results bear on the potential use of this energy transfer process to measure distances in biological macromolecules. It is evident that the length of such a spectroscopic ruler can readily be controlled by varying the magnitude of the spectral overlap integral of the energy donor-acceptor pair.
AN EXAMPLE IN SURFACE AREA
Authors: Goffman Casper
Published: May 2006

For length and area, a central fact is that the value of the length of a curve or the area of a surface, as given by the Lebesgue theory, is at least as great as that given by the classical formula, whenever the latter has meaning. This is now found not to be valid in higher dimensions. We give an example of a continuous mapping of the unit cube into itself for which the value given by the formula exceeds the three-dimensional Lebesgue area of the corresponding suface.
FLEXIBLE POWER-ASSOCIATIVE ALGEBRAS OF DEGREE 1
Authors: Oehmke Robert H.
Published: May 2006

It is shown here that there are essentially two different types of simple flexible, strictly power-associative finite dimensional algebras of degree 1; namely, the fields and the algebras of Kokoris. This follows readily from the perhaps more basic result that characterizes the simple commutative power-associative finite dimensional algebras of degree 1 as fields.
IMMUNOCHEMISTRY OF THE CAPSULAR POLYSACCHARIDE OF AN
Acinetobacter
Authors: Heidelberger Michael , Das Amalendu , Juni Elliot
Published: May 2006

The capsular polysaccharide of a strain, BD4, of
Acinetobacter calco-aceticus
(A.c-a), composed of L-rhamnose and D-glucose, 4:1, precipitates all streptococcal group B antisera tested, as well as streptococcal group G antisera and antipneumococcal (Pn) type XXIII serum. Nonreducing end groups of L-rhamnose, known to be major determinants of the antigens giving rise to these antisera, are thus identified in A.c-a, which also precipitates anti-Pn VI sera. Both the rhamnose and glucose in the capsular polysaccharide (S) of Pn VI are linked 1,3-, as is the rhamnose in Pn S II, which also precipitates anti-Pn VI because of this linkage. A.c-a and S II precipitate the same fraction of anti-Pn VI, identifying a second portion of the rhamnose of A.c-a as 1,3-linked. This is confirmed by the stability of a portion of the rhamnose on oxidation of A.c-a with periodate, and 1,3-linked glucose or a periodate-stable branch point is also indicated in the same way. Two features of the fine structure of A.c-a have thus been established and a third indicated.
INCREASED SURVIVAL IN MICE INOCULATED WITH TUMOR CELLS AND TREATED WITH INTERFERON PREPARATIONS
Authors: Gresser I. , Bourali C. , Lévy J. P. , Fontaine-Brouty-Boyé D. , Thomas M. T.
Published: May 2006

Repeated administration of potent mouse interferon preparations increased the survival of Balb/c and C 57/B1
6
mice inoculated with 2,000-3,000 RC
19
and EL
4
tumor cells. Only 7/188 (3.7%) untreated mice (or mice treated with control preparations) survived more than 22 days after intraperitoneal inoculation of RC
19
tumor cells. None survived more than 60 days. In contrast, 101/103 (98%) interferon-treated mice survived beyond 22 days, and sixteen (15%) survived more than 60 days. None of these 16 surviving mice show any sign of tumor at present. Three mice (of the 16) from an early experiment are alive ten months after inoculation of RC
19
tumor cells.

Mouse interferon preparations derived from three different tissue sources— brain, serum, and monolayer cell cultures (with Newcastle disease virus and West Nile virus as interferon-inducing agents)—all proved effective. A
purified
preparation of mouse brain interferon was as effective as crude brain interferon. Human amniotic membrane interferon and control tissue preparations were without effect. These findings suggest that interferon itself (or a factor closely associated with interferon) is the active moiety in these preparations.
MINIMIZATION OF POLYPEPTIDE ENERGY, VII. SECOND DERIVATIVES AND STATISTICAL WEIGHTS OF ENERGY MINIMA FOR DECA-L-ALANINE
Authors: Gibson K. D. , Scheraga H. A.
Published: May 2006

The matrix of second derivatives of 21 apparent local energy minima of deca-L-alanine has been computed. The results show that all these conformations are true local energy minima and, therefore, potentially stable conformations for this peptide. Calculations of the relative statistical weights of these conformations confirm earlier theoretical considerations on the importance of the librational free energy of stable conformations of peptides. As predicted earlier, the relative statistical weights of the local energy minima do not always fall in the same order as the relative energies.
TOWARD A STOCHASTIC CALCULUS, I
Authors: McShane E. J.
Published: May 2006

Differential equations, deduced by physical theory for systems subjected to practically possible (Lipschitzian) random disturbances, can also be solved for martingale (e.g., Brownian-motion) disturbances by interpreting integrals as Itô integrals. But the two theories are not unified, and disconcerting differences appear. In this note and the next, we present the foundations of a unified theory, developed far enough to eliminate the discrepancies. Here we develop the tools; stochastic integration is extended to apply to a class of random functions including Lipschitzian and Brownian-motion processes, and a new kind of integral, called “doubly stochastic,” is defined and shown to exist under adequately general hypotheses.
SECONDARY STRUCTURES OF DNA
Authors: Wu Tai Te
Published: May 2006

In view of the differences of the X-ray diffraction patterns for DNA fibers at 66 and 92 per cent relative humidities, it is proposed that the secondary structure of DNA consists of two partially intercalated double helices at 92 per cent. Possible biological implications are discussed.
STUDIES ON REPRESSION OF THE HISTIDINE OPERON, II. THE ROLE OF THE FIRST ENZYME IN CONTROL OF THE HISTIDINE SYSTEM
Authors: Kovach John S. , Phang James M. , Ference Michael , Goldberger Robert F.
Published: May 2006

Recent studies on repression of the enzymes for histidine bio-synthesis in
Salmonella typhimurium
demonstrated that the kinetic pattern in which the enzymes become repressed is influenced by the state of the feedback-sensitive site of the first enzyme of the pathway (Kovach
et al., J. Bacteriol.,
97, 1283 (1969)). In the present study we demonstrate that under certain conditions alteration of the feedback-sensitive site of the first enzyme prevents repression of the histidine operon. We conclude that the first enzyme plays a previously unrecognized role in regulation of the histidine system.
MEMBRANES OF ANIMAL CELLS, III. AMINO ACID INCORPORATION BY ISOLATED SURFACE MEMBRANES
Authors: Glick Mary Catherine , Warren Leonard
Published: May 2006

Surface membranes isolated from mouse fibroblasts contain RNA organized in ribosome-like particles. These surface membranes can incorporate radioactive amino acids into material insoluble in hot trichloroacetic acid. Characterization of the radioactive products indicated that they are large polypeptides. Most requirements and inhibitors of the system were similar to those of the microsomal system of the endoplasmic reticulum. Further comparisons were made with microsomal and pH 5 fractions prepared from L-cells by standard procedures and by two methods attempting to simulate the conditions necessary for isolating surface membranes. The amount of L-leucine incorporated by the surface membranes per mg of RNA was comparable to the values obtained by the microsomal and pH 5 fractions prepared by standard procedures. In contrast, the activity of the two other microsomal fractions was less than 10 per cent of this amount. The most striking difference noted was in the products formed by the surface membranes and by the microsomal systems. These products were demonstrated to be quite different by electrophoresis on acrylamide gels. It is suggested that the surface membranes participate actively in protein synthesis
in vivo
, and that, because of this location, the protein-synthesizing mechanism may be able to perform special functions more efficiently.
STRUCTURAL PARAMETERS OF NERVE MYELIN
Authors: Worthington C. R.
Published: May 2006

Low-angle X-ray data from live myelinated nerve are interpreted in terms of an electron density strip model containing a total of seven parameters. Model parameters are assigned to three varieties of peripheral nerve and two kinds of central nervous system nerve. Cytoplasmic and extracellular fluid channels which occur as independent layers parallel to the plasma membrane surface are identified and described. An explanation of the Patterson function of myelinated nerve is given in terms of the proposed electron density strip model.
DIRECT SOLUTION OF GENERAL ONE-DIMENSIONAL LINEAR PARABOLIC EQUATION VIA AN ABSTRACT PLANCHEREL FORMULA
Authors: Hersh Reuben
Published: May 2006

We use the formalism of Fourier transformation to derive a functional calculus for the generator of an abstract group. As an application we obtain a new direct solution of Cauchy's problem for one-dimensional stationary parabolic equations of arbitrary order with bounded coefficients.
COHOMOLOGY OF KLEINIAN GROUPS
Authors: Kra Irwin
Published: May 2006

Let [unk] be a (nonelementary) Kleinian group and
q
≥ 2 an integer. The group [unk] acts in a natural way on the vector space II

2
q
—2

of complex polynomials in one variable of degree ≤ 2
q
— 2. One can thus form
H
1
([unk],II

2
q
—2

), the first cohomology group of [unk] with coefficients in II

2
q
—2

. There are essentially two ways of constructing cohomology classes. One construction originated with Eichler and has recently been extended by Ahlfors. Another construction is due to Bers. We show that for finitely generated [unk], every cohomology class pε
H
1
([unk],II

2
q
—2

) can be written uniquely (if one chooses an invariant union of components of [unk]) as a sum of a Bers cohomology class and an Eichler cohomology class. Similar decompositions are obtained for the subgroups of parabolic cohomology classes introduced by Ahlfors. Some information on the structure of
H
1
([unk],II

2
q
—2

) for infinitely generated groups [unk] is also obtained.
HEARING IN THE BLACKFOOTED PENGUIN,
Spheniscus demersus
, AS REPRESENTED BY THE COCHLEAR POTENTIALS
Authors: Wever Ernest Glen , Herman Paul N. , Simmons James A. , Hertzler David R.
Published: May 2006

A study of the hearing of the penguin
Spheniscus demersus
, in terms of the cochlear potentials, showed sensitivity over a range at least of 100 to 15,000 Hz, with the best sensitivity in the region of 600 to 4000 Hz. The form of the sensitivity function is consistent with the vocalizations of these animals. In general, this species of penguin shows good agreement with other birds in both the form and range of auditory sensitivity.
INTERFERON SYNTHESIS IN X-IRRADIATED ANIMALS, IV. DONOR-TYPE SERUM INTERFERONS IN RAT-TO-MOUSE RADIATION CHIMERAS INJECTED WITH NEW CASTLE DISEASE VIRUS
Authors: De Maeyer-Guignard Jaqueline , De Maeyer Edward , Jullien Pierre
Published: May 2006

C
3
H/He mice were exposed to total-body X-irradiation of 1000 roentgens and received thereafter 10
7
xenogeneic Wistar rat marrow cells intravenously. In these rat-to-mouse chimeras, serum interferon-producing capacity upon injection of Newcastle disease virus was examined four weeks after grafting. Normal levels of circulating interferon were produced. The interferon, however, had the species specificity of rat interferon, being 20 times more active in rat embryo fibroblasts than in mouse embryo fibroblasts. Moreover, it behaved like rat interferon when filtered on Sephadex G-100 dextran gel, displaying one peak of activity in the 90,000 molecular-weight range and two incompletely separated peaks of 32,000 and 24,000, respectively, in the 30,000 molecular-weight region. The fact that the interferon is of the donor type in rat-to-mouse chimeras permits us to conclude that circulating interferon induced by New-castle disease virus is made in bone-marrow-derived cells.
KINETICS OF MEMORY CONSOLIDATION: ROLE OF AMNESIC TREATMENT PARAMETERS
Authors: Cherkin Arthur
Published: May 2006

The consolidation theory states that with the passage of time the engram of a recent learning experience grows increasingly resistant to disruption by amnesic treatment. The time required to reach complete resistance (“consolidation time”) is a controversial issue; current estimates range from 10
1
to 10
5
seconds. The present study suggests a parsimonious interpretation of the divergence, namely, that weak amnesic treatments fail to block memory consolidation but do slow its rate, so that post-treatment consolidation inflates the retention scores measured 24 hours later and leads to variably shortened “consolidation times.”

This study utilized 2880 neonate chicks trained in a one-trial avoidance paradigm. Retrograde amnesia was induced by treatment with flurothyl (CF
3
CH
2
-OCH
2
CF
3
) vapor. Apparent “consolidation times” determined by conventional data analysis varied widely as a function of flurothyl concentration and exposure time, ranging from 4 minutes under weak amnesic conditions (0.85% flurothyl; 1-min exposure) to 24 hours under strong conditions (1.7% flurothyl; 8-min exposure). With 1.7% flurothyl, the consolidation half-time was found to be 9.8 hours.
NONHEME IRON PROTEINS, XI. SOME GENETIC ASPECTS
Authors: Benson Ann Marie , Yasunobu Kerry T.
Published: May 2006

Ferredoxin was isolated from individual
Leucaena glauca
trees, and the distribution of amino acids at three of the four sites of sequence heterogeneity was determined. The results indicated that the most probable causes of the observed microheterogeneity are the presence of either nonallelic nuclear genes or differing chloroplast genes, and also ambiguity in translation of the genetic code.
PTERIDINES AND THE FUNCTION OF THE PHOTOSYNTHETIC REACTION CENTER
Authors: Fuller R. C. , Nugent N. A.
Published: May 2006

The photoreduction and interaction with the photosynthetic “reaction center” of 2-amino,4-hydroxy-6-substituted pteridine indicates that these low-potential (∼ -0.7 v), naturally occurring compounds play a primary role in photosynthetic electron transport. These unconjugated pteridines, which occur in association with the photosynthetic apparatus of green plants and photosynthetic bacteria, can be reduced by light in the presence of a bacterial chromatophore fraction from the dihydro form to the tetrahydro form. 6,7-Dimethyl-tetrahydropteridine readily reduces spinach ferredoxin. This compound also specifically interacts with reaction-center chlorophyll and bacteriochlorophyll and produces spectral shifts similar to those produced by light. It is proposed that the electron produced by excited-state chlorophyll is captured and separated by a pteridine at -0.67 v at the photosynthetic reaction center.
BRAIN NOREPINEPHRINE: EVIDENCE THAT NEURONAL RELEASE IS ESSENTIAL FOR SHAM RAGE BEHAVIOR FOLLOWING BRAINSTEM TRANSECTION IN CAT
Authors: Reis Donald J. , Fuxe Kjell
Published: May 2006

There is a direct relationship between the magnitude of sham rage produced by brainstem transection in cat and the decrease of brainstem norepinephrine. The attacks of rage are augmented by protriptyline and inhibited by haloperidol, drugs respectively facilitating or depressing the action of norepinephrine centrally. Release of norepinephrine by brainstem neurons appears essential for appearance of this behavior.
ORIENTATION OF LIPID SPIN LABELS IN LECITHIN MULTILAYERS
Authors: Libertini L. J. , Waggoner A. S. , Jost P. C. , Griffith O. H.
Published: May 2006

Nitroxide-labeled stearic acid and cholestane have been incorporated into lecithin multilayers. The pronounced anisotropy of the preparations reflects a nonrandom structure of the lecithin film and demonstrates that these lipid probes can report structural information from lipid regions resembling those thought to occur in membranes. These two probes differ with respect to the orientation of the NO bond to the long axis, but both orient with their long axes perpendicular to the phospholipid film. Simulated spectra, calculated on the basis of a Gaussian distribution of orientations, are in agreement with the experimental results.
α-KETO ACID DEHYDROGENASE COMPLEXES, XI. COMPARATIVE STUDIES OF REGULATORY PROPERTIES OF THE PYRUVATE DEHYDROGENASE COMPLEXES FROM KIDNEY, HEART, AND LIVER MITOCHONDRIA
Authors: Linn Tracy C. , Pettit Flora H. , Hucho Ferdinand , Reed Lester J.
Published: May 2006

The activity of the multienzyme pyruvate dehydrogenase complexes, isolated from mitochondria of beef kidney, beef heart, and pork liver, is regulated by phosphorylation and dephosphorylation. Phosphorylation and concomitant inactivation of each of the three complexes are catalyzed by an ATP-specific kinase, and dephosphorylation and concomitant reactivation are catalyzed by a phosphatase. The phosphatase has been separated from the other component enzymes of each pyruvate dehydrogenase complex, and the three phosphatases are functionally interchangeable. The kinase has been isolated from the beef kidney complex, and it is functional with the beef heart and pork liver complexes. ADP is competitive with ATP, and the ADP effect is more pronounced with the kidney kinase than with the liver and heart kinases. Pyruvate protects strongly the heart and liver pruvate dehydrogenase complexes and, to a lesser extent, the kidney complex against inactivation by ATP. Pyruvate apparently exerts its effect on the pyruvate dehydrogenase component of the complex, rather than on the kinase.
DEUTERATED OXYTOCINS: THE SYNTHESIS AND BIOLOGICAL PROPERTIES OF A CRYSTALLINE ANALOG OF DEAMINO-OXYTOCIN DEUTERATED IN THE 5-ASPARAGINE POSITION
Authors: Blomquist Alfred T. , Rich Daniel H. , Carlson Bruce A. , Allen G. Ashley , Hruby Victor J. , Takashima Herbert , Nangeroni Louis L. , Glose Paula , Vigneaud Vincent Du
Published: May 2006

This paper describes the synthesis and biological activity of [5-L-asparagine-α,β,β-
d
3
]-deamino-oxytocin. The model peptide
S
-benzyl-β-mercaptopropionyl-L- asparaginyl-α,β,β-
d
3
-glycinamide was also prepared to observe the effect of the conditions of peptide synthesis on the deuterium content. It was found that normal synthetic procedures could be used without a significant loss in the deuterium content.

The [5-L-asparagine-α,β,β-
d
3
]-deamino-oxytocin had, within experimental error, the same avian vasodepressor and oxytocic activities as deamino-oxytocin itself.
SYNTHETIC SPECTROSCOPIC MODELS RELATED TO COENZYMES AND BASE PAIRS, IV. STACKING INTERACTIONS IN TRNA; THE ANTICODON-ADJACENT BASE
Authors: Leonard Nelson J. , Iwamura Hajime , Eisinger Josef
Published: May 2006

In order to test the Fuller and Hodgson hypothesis that modification of the anticodon-adjacent base in certain tRNA's not only prevents mRNA base-pairing at that site but also increases the stabilization of a stacked conformation in the anticodon loop, we have examined the interaction between adenosine and its N
6
-isopentenyl derivative by means of model compounds. The synthetic 9-[3-(aden-9-yl)propyl]-6-(3-methyl-2-butenylamino)purine, Ad-C
3
-iPAd (IV), in which the adenine and N
6
-substituted adenine moieties are joined at the 9 and 9′ positions by a trimethylene chain, served as a useful spectroscopic model for assessing the base-base interaction free from the complicating features of the carbohydrate and phosphodiester groupings. The hypochromism for the model, which was determined in dilute aqueous solution and represents the decrease in integrated ultraviolet absorption intensity of Ad-C
3
-iPAd (IV) compared with equimolar 9-propyladenine (Ad-C
3
) and 6-(3-methyl-2-butenyl-amino)-9-propylpurine (V, iPAd-C
3
), was 17.9 per cent in neutral solution, 8.4 per cent in 0.1
N
HCl, and 18.5 per cent in 0.1
N
NaOH. Comparison with the per cent hypochromism calculated for the simple model Ad-C
3
-Ad (e.g., 16.5% in neutral solution) confirms the strong interaction in IV observed between uncharged plane-parallel adenine and N
6
-substituted adenine rings. The cause for changes in the absorption spectrum of Ad-C
3
-iPAd are discussed. The fluorescence and phosphorescence emission spectra of Ad-C
3
-iPAd in ethylene glycol-water glass at 80°K add considerable weight to the conclusion that there is a strong tendency for adenine and N
6
-(Δ
2
-isopentenyl)adenosine (I) to stack if this is permitted by steric considerations.
AVIFAUNAL EQUILIBRIA AND SPECIES TURNOVER RATES ON THE CHANNEL ISLANDS OF CALIFORNIA
Authors: Diamond Jared M.
Published: May 2006

Insular species diversities, and their dependence on island size and isolation, have been postulated to represent a dynamic equilibrium between species immigration rates and species extinction rates. This interpretation has been tested by determining the land and freshwater birds breeding on the nine Channel Islands off southern California in 1968 and comparing the results with a similar survey for the years up to 1917. Most of the islands were found to be in equilibrium as to number of species, but between 17 and 62 per cent of the 1917 breeding species had disappeared by 1968, and an approximately equal number of new immigrant species had become established. Percentage turnover rates vary inversely as insular species diversities, with no effect of distance apparent.
CELLS INVOLVED IN THE IMMUNE RESPONSE, XIII. THE NATURE OF THE CELLULAR INTERACTIONS RELATING ANTIBODY FORMATION AND IMMUNOLOGIC TOLERANCE: A UNIFIED HYPOTHESIS
Authors: Richter Maxwell
Published: May 2006

The various cells and cell pathways involved in the induction of the primary humoral immune response have been discussed from the point of view of the unitary, as opposed to the multiple, pathway concept. The immunocompetent cells made unresponsive in the immunologically tolerant animal and the cells capable of responding with antibody formation were considered. It is concluded that there exist multiple cellular pathways through which the humoral immune response may be expressed.
RNA SYNTHESIS IN CELLS INFECTED WITH HERPES SIMPLEX VIRUS, II. EVIDENCE THAT A CLASS OF VIRAL mRNA IS DERIVED FROM A HIGH MOLECULAR WEIGHT PRECURSOR SYNTHESIZED IN THE NUCLEUS
Authors: Wagner Edward K. , Roizman Bernard
Published: May 2006

Viral RNA extracted from the cytoplasmic polyribosomes of human epidermoid carcinoma no. 2 cells infected with herpes simplex virus (mRNA) had a sedimentation coefficient between 10
S
and 20
S
while that from nuclei of infected cells varied in size from 10
S
to >80
S
. Estimates of the maximum molecular weight of viral RNA from its sedimentation coefficients suggest that at least 10 per cent of the viral genome is transcribed as a single molecule. The ratio of RNA of different sizes found in the nuclei of cells pulse labeled for 12 minutes was approximately the same as those found in cells labeled for longer intervals implying that either some classes of viral mRNA were made as small molecules or that the large viral RNA molecules were cleaved soon after synthesis. Cytoplasmic mRNA competed to a level of at least 80 per cent in viral DNA-RNA hybridization tests with >50
S
RNA extracted from nuclei of infected cells. This is consistent with the hypothesis that viral mRNA is produced by cleavage of a large precursor RNA molecule.
REPRESSION-DEPENDENT ALTERATION OF AN ARGININE ENZYME IN
Escherichia coli
Authors: Leisinger Thomas , Vogel Ruth H. , Vogel Henry J.
Published: May 2006

Treatment of susceptible
Escherichia coli
K12 derivatives with 0.4
M
Mg
++
at 37°, potentiated by L-arginine or L-canavanine, leads to alteration of acetylornithine δ-transaminase. The alteration, obtained in the absence of protein synthesis and reversible at 0 or 37°, is manifested in extracts by lowered activity and modified substrate affinity behavior of the enzyme without gross changes in sedimentation properties. Cells grown under arginine repression are susceptible to the treatment; cells grown under genetic or steady-state physiological derepression are not. Transaminase synthesized during early derepression can be altered, although to progressively diminishing extents. Enzyme formed under steady-state derepression becomes alterable following transition to repression. The Mg
++
-dependent alteration can be thought to arise while the enzyme, arginine (or canavanine), and aporepressor are in contact, and to reflect a physiological process such as the participation of the enzyme in the repressive complex.
THE REPLICATION OF THE RING-SHAPED DNA OF POLYOMA VIRUS, I. IDENTIFICATION OF THE REPLICATIVE INTERMEDIATE
Authors: Bourgaux Pierre , Bourgaux-Ramoisy Danielle , Dulbecco Renato
Published: May 2006

The replication of the ring-shaped polyoma DNA has been investigated. The replicative intermediate has been identified and characterized; it consists of molecules containing both circular and nicked strands, not longer than the strands of the DNA found in viral particles. The findings exclude certain proposed methods of replication of ring-shaped DNA and are compatible with Cairns' model.
FACTORS INFLUENCING PREMATURE INDUCTION OF UDP-GLUCURONYLTRANSFERASE ACTIVITY IN CULTURED CHICK EMBRYO LIVER CELLS
Authors: Skea Brian R. , Nemeth Andrew M.
Published: May 2006

Very young (5-day-old) chick embryo livers during organ culture on rafts over a chemically defined nutrient medium precociously develop, from zero, adult levels of UDP-glucuronyltransferase activity. Induction of enzyme does not require DNA synthesis or mitosis, or exposure to hormones, serum, or tissue extracts. Thus, this functional differentiation of embryo liver is apparently not dependent on cell proliferation or on extrinsic substances other than simple nutrients.

UDP-glucuronyltransferase activity develops rapidly also in embryo liver cells cultured as monolayers or aggregates; specific activity of enzyme on a protein basis increases at the same rate in cells undergoing widely different rates of cell division, and net protein synthesis.

These findings suggest that precocious development of UDP-glucuronyltransferase activity in chick embryo liver is due, not to incidents of culture, but to removal from the embryonic environment. Supporting this, chick embryo liver grafted to the chorioallantoic membrane does not develop UDP-glucuronyltransferase activity until subsequently transferred to an
in vitro
cell culture system.
ORBITING CLUSTERS IN ATOMIC NUCLEI
Authors: Pauling Linus
Published: May 2006

As an alternative to their description as vibrational levels, the low excited states of even-even nuclei can be described as rotational states of a helion, dineutron, diproton, or other cluster about the rest of the nucleus, leading to reasonable values of the average distance between centers of the clusters. Some states involve rotational excitation of two or more helions or other clusters. The nature of the rotating clusters is determined by the relation of the neutron and proton numbers to the magic numbers.
INTERACTION OF A BACTERIAL ADENOSINE TRIPHOSPHATASE WITH PHOSPHOLIPID BILAYERS
Authors: Redwood W. R. , Müldner H. , Thompson T. E.
Published: May 2006

A solubilized nonparticulate adenosine triphosphatase from
Streptococcus fecalis
spheroplast membranes (Abrams, A., and C. Baron,
Biochemistry
, 7,501 (1968)) interacts at pH 7.5 with lipid bilayer membranes to produce a 10
2
- to 10
4
-fold increase in the electric conductance of the bilayer. In addition, a small decrease in the electrical capacitance of the interactant system is also observed. Interaction is obtained with bilayers formed from a solution in
n
-decane of either purified egg phosphatidyl-choline, synthetic diphytanoyl phosphatidyl-choline, or a total extract of the membrane lipid of
S. fecalis
. The magnitude of the increase in conductance is dependent on the presence of Mg
++
and upon the concentrations of both Na
+
and K
+
in the range of 10
-2
to 10
-1
M
. An additional tenfold increase in conductance is obtained when ATP is added to the ambient aqueous phase surrounding the bilayer ATPase interactant system. No conductance change is obtained with ATPase which has been treated with pronase. ATPase activity is dependent upon Mg
++
and upon the concentrations of Na
+
and K
+
in the region of 10
-1
M
. The function of the ATPase in the intact bacterial membrane is apparently associated with the active transport of cations. The increased conductance in the bilayer which results from its interaction with the ATPase, together with the similarity between the dependence of this interaction and the dependence of ATPase activity on Mg
++
, ATP, and the Na
+
, K
+
concentrations suggests that the bilayer-ATPase interactant complex may be similar in structure and properties to the membrane-ATPase complex in the intact organism.
CHICK CARTILAGE COLLAGEN: A NEW TYPE OF α1 CHAIN NOT PRESENT IN BONE OR SKIN OF THE SPECIES
Authors: Miller Edward J. , Matukas Victor J.
Published: May 2006

Isolation and chromatography of collagen from chick cartilage revealed an excess of α1 relative to α2-chains. Characterization of the cyanogen bromide peptides from the α1 fraction indicated the presence of two homologous forms of α1. The results suggest that cartilage contains two collagens, one identical to the collagen of skin and bone, the other clearly different requiring the expression of an additional structural gene and possibly containing only α1-chains.
ISOACCEPTING TRANSFER RNA'S OF L-M CELLS IN CULTURE AND AFTER TUMOR INDUCTION IN C
3
H MICE
Authors: Yang Wen-Kuang , Hellman A. , Martin D. H. , Hellman K. B. , Novelli G. David
Published: May 2006

Co-chromatography in a reversed-phase column was performed for 16 aminoacyl-tRNA's prepared from L-M cells grown in serum-free suspension culture and from tumors induced in irradiated C
3
H mice by subcutaneous injection of L-M cells. The results showed that between the two sources there were (1) marked differences in aspartyl-, histidyl-, phenylalanyl-, and tyrosyl-tRNA's; (2) significant quantitative differences in isoaccepting species of alanyl-, isoleucyl-, seryl-, and threonyl-tRNA's; and (3) similar to minimally different patterns of arginyl-, methionyl-, prolyl-, tryptophanyl-, valyl-, glycyl-, leucyl-, and lysyl-tRNA's. The differences were evident when synthetases prepared either from L-M cells or from the tumors were used. When the L-M tumors were brought back into
in vitro
culture, their tRNA patterns were like those of L-M cells. Addition of serum to the culture medium caused the L-M cells to show very minute, but detectable, amounts of the isoaccepting tRNA's found in the tumors. The cellular mechanisms which may be related to the changes of tRNA patterns in the L-M cells are discussed.
Inference from Inadequate and Inaccurate Data, I
Authors: Backus George
Published: May 2006

Having measured
D
numerical properties of a physical object
E
which requires many more than
D
parameters for its complete specification, an observer seeks to estimate
P
other numerical properties of
E
. This paper describes how he can proceed when
E
is adequately described by one member

m
E

of a Hilbert space [unk] of possible models of
E
, when he believes that the Hilbert norm of

m
E

is very likely rather smaller than some known number
M
, and (except for section 6) when all the observed and sought-after properties of
E
are continuous linear functionals on [unk]. Section 6 treats Frechet-differentiable non-linear functionals. A later paper will reduce unbounded functionals on arbitrary topological linear spaces to the present case.
Fourier Analysis on GL(n,R)
Authors: Gelbart Stephen S.
Published: May 2006

Two problems of Fourier analysis on
GL
(
n
,
R
) are studied. The first concerns the decomposition of the additive Fourier operator in terms of the group representation theory of
G
. The second concerns the analytic continuation of certain zeta-functions defined on
G
. It is found that the generalized Gamma functions of Gelfand and Graev arise naturally in the solution of both these problems.
RNA Metabolism in Goldfish Brain during Acquisition of New Behavioral Patterns
Authors: Shashoua Victor E.
Published: May 2006

Base composition measurements were used as a criterion of RNA changes in goldfish brain. RNA synthesized during the acquisition of new swimming skills was found to have a uridine/cytidine ratio 20-80 per cent higher than that of RNA formed under nonlearning conditions. A variety of behavioral situations were used to demonstrate that these RNA changes were not due to such factors as intense physical exertion, passive responses to stress, or the intense electrical activity of the brain and convulsive behavior produced by KCl injections. The RNA changes were produced by two behavioral situations; (1) during the process of acquiring new swimming skills, and (2) as a result of attempts to master an impossible task. The results suggest that the modified RNA synthesis taking place during the acquisition of new behavioral patterns is probably not specific as to the particular information content being stored, but may be required for the consolidation step of new information storage.
A Setting for A Theorem of Bott
Authors: Morse Marston , Cairns Stewart S.
Published: May 2006

Inspired by Theorem A of Raoul Bott,
1
Morse and Cairns
2
have stated Corollary 23.3 below, a theorem of essentially the same character as Theorem A of Bott. The symbol [unk] in Corollary 23.3 means that the sets to the left and right of [unk] have the same
homotopy type
in the sense of Hilton (ref. 3, p. 3). Corollary 23.3 gives a setting to Bott's theorem in the theory of „bowls” introduced by Morse. The object of this note is to clarify and reinterpret the analysis presented as proof of Corollary 23.3 in reference 2.