bluuebunny/crossref_metadata_2025 huggingface dataset:
A Native American community's involvement and empowerment to guide their children's development in the school setting
Authors: Rivera Héctor H. , Tharp Roland G.
Published: May 2006

This study provides an empirical description of the dimensions of community values, beliefs, and opinions through a survey conducted in the Pueblo Indian community of Zuni in New Mexico. The sample was composed of 200 randomly chosen community members ranging from 21 to 103 years old. A principal component factor analysis was conducted, as well as a multivariate analysis of variance, to explore gender, age, education, language, and socioeconomic (SES) differences on values, beliefs, and opinions from survey participants. Overall, the findings suggest a strong agreement by the community on the direction to be taken by their school district in their efforts to improve classroom instruction, as well as in their efforts to guide their children's development as Native Americans. © 2006 Wiley Periodicals, Inc.
Intra‐ and interreader reproducibility of magnetic resonance imaging for quantifying the lipid‐rich necrotic core is improved with gadolinium contrast enhancement
Authors: Takaya Norihide , Cai Jianming , Ferguson MT Marina S. , Yarnykh Vasily L. , Chu Baocheng , Saam Tobias , Polissar Nayak L. , Sherwood Jane , Cury Ricardo C. , Anders Robert J. , Broschat Kay O. , Hinton Denise , Furie Karen L. , Hatsukami Thomas S. , Yuan Chun
Published: May 2006

Purpose

To test the hypothesis that intra‐ and interreader reproducibility for measuring the lipid‐rich necrotic core (LR‐NC) size is significantly improved with gadolinium (Gd) contrast‐enhanced magnetic resonance imaging (CEMRI) compared to non‐CEMRI.

Materials and Methods

Thirty‐seven individuals with >50% carotid artery stenosis underwent carotid MRI at 1.5T (pre‐ and postcontrast T1‐weighted (T1W), T2‐weighted (T2W), proton density‐weighted (PDW), and three‐dimensional time‐of‐flight (TOF) sequences). Two independent readers measured the mean area of the LR‐NC from the precontrast images only, followed by a second measurement using the additional postcontrast images. One reader repeated the measurements after an interval of five months. Intra‐ and interreader reproducibility was analyzed by means of the intraclass correlation coefficient (ICC), coefficient of variation (CV), and standard deviation (SD).

Results

The CV decreased from 33.7% to 8.8% for intrareader measurements of the LR‐NC, and from 33.5% to 17.6% for interreader measurements. The SD was significantly smaller with CEMRI than with non‐CEMRI (P = 0.003 and P = 0.006, respectively). The ICC increased from 0.94 to 0.99 and from 0.85 to 0.93 for the intra‐ and interreader measurements, respectively.

Conclusion

Reader reproducibility for in vivo MRI quantification of LR‐NC size is significantly improved by the addition of Gd contrast in individuals with >50% carotid stenosis. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Free‐breathing delayed hyperenhanced imaging of the myocardium: A clinical application of real‐time navigator echo imaging
Authors: Goldfarb James W. , Shinnar Meir
Published: May 2006

Purpose

To compare a free‐breathing (FB) acquisition with the current standard of breath‐holding (BH) in a clinical setting using identical two‐dimensional MR pulse sequences for imaging of myocardial delayed hyperenhancement.

Materials and Methods

Two‐dimensional gadolinium‐enhanced images were acquired using FB and BH techniques in 18 subjects to evaluate delayed enhancement of myocardial infarction. The FB acquisition used a navigator echo to monitor the position of the right hemidiaphragm for respiratory gating and correction. Visual analysis using a 16‐segment model, quantitative signal difference to noise ratios, and percent left ventricle (LV) viability measurements for the two acquisition types were statistically compared.

Results

An excellent agreement between two‐dimensional BH and two‐dimensional FB acquisitions was found. In one patient, a nontransmural infarct was seen only in the FB images. There were no statistically significant differences in the number of infarcted segments or the measured signal difference to noise ratios (SDNR) between the two methods. Linear regression and Bland Altman analysis of the percentage LV viable myocardium yielded a good fit and narrow limits of agreement.

Conclusion

An FB navigator echo acquisition can be effectively used in the setting of myocardial delay hyperenhanced imaging. Image quality is similar or superior to that of BH imaging. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Architectural reorganization of the nuclei upon transfer into oocytes accompanies genome reprogramming
Authors: Martin Catherine , Brochard Vincent , Migné Carole , Zink Daniele , Debey Pascale , Beaujean Nathalie
Published: May 2006

The ability of cloned embryos to sustain full‐term development depends on the ability of the recipient ooplasm to reprogram the donor cell genome. As the nuclear architecture has recently emerged as a key‐factor in the regulation of gene expression, we questioned whether early embryos obtained from transfer of ES metaphasic chromosomes into mouse ooplasm would adopt the somatic or embryonic type of nuclear organization. We have particularly focused on the arrangement of chromosomal territories with respect to the nucleolar compartment, and the pericentric heterochromatin domains called chromocenters. We found that nuclear transfer triggers profound chromatin rearrangements including the dispersion of the donor cell chromocenters components. These rearrangements lead to a typical 1‐cell pronuclear organization, namely a radial arrangement of the chromosome territories with centromeres attached to the nucleoli, which adopt the compact fibrillar structure of nucleolar precursor bodies (NPBs). Subsequently, during the second cycle, the cloned embryos undergo further reorganization with the establishment of new chromocenters, clustered in one part of the nucleus, as during normal embryogenesis. We could also establish that the adequate distribution of chromosomal territories at the pronuclear stage seems important for the development until blastocyst. Mol. Reprod. Dev. 1102–1111, 2006. © 2006 Wiley‐Liss, Inc.
Development and plasticity‐related changes in protein expression patterns in cat visual cortex: A fluorescent two‐dimensional difference gel electrophoresis approach
Authors: Van den Bergh Gert , Clerens Stefan , Firestein Bonnie L. , Burnat Kalina , Arckens Lutgarde
Published: May 2006

During early postnatal brain development, changes in visual input can lead to specific alteration of function and connectivity in mammalian visual cortex. In cat, this so‐called critical period exhibits maximal sensory‐driven adaptations around postnatal day 30 (P30), and ceases toward adulthood. We examined the molecular framework that directs age‐ and experience‐dependent plasticity in cat visual cortex, by comparing protein expression profiles at eye opening (postnatal day 10 (P10), when experience‐dependent plasticity starts), the peak of the critical period (P30), and in adulthood. Using 2‐D DIGE, we performed comparisons of P10–P30 and P30‐adult brain protein samples. Sixty protein spots showed statistically significant intensity changes in at least one comparison. Fifty‐one spots were identified using quadrupole‐TOF MS/MS or LC‐MS/MS, containing 37 different proteins. The progressive increase or decrease in protein expression levels could be correlated to age‐dependent postnatal brain development. Four spots containing transferrin, 14–3‐3 alpha/beta and cypin, showed maximal protein expression levels at P30, thereby showing a positive correlation to critical period plasticity. Western analysis indeed revealed a clear effect of visual deprivation on cypin expression in cat visual cortex. Our results therefore demonstrate the power of 2‐D DIGE as a tool toward understanding the molecular basis of nervous system development and plasticity.
Solvent‐free polymerization of citric acid and D‐sorbitol
Authors: Doll Kenneth M. , Shogren Randal L. , Willett J. L. , Swift Graham
Published: May 2006

Copolymers of citric acid and D‐sorbitol were synthesized with a solvent‐free vacuum‐oven synthesis with molar ratios of citric acid to D‐sorbitol ranging from 1/1 to 6/1. The extent of the reaction was followed by the monitoring of the residual acid content of the system. As expected, the reaction occurred much more rapidly at 150 than at 110 °C. The Fourier transform infrared (FTIR) spectra of the products showed the expected FTIR bands at approximately 1735 and 1188 cm−1, which were indicative of ester formation. Gel permeation chromatography showed a major product with a molecular weight of approximately 3500 Da. An insoluble material with a water‐absorption index of up to 17 was also synthesized and could lead to possible applications as absorbers, thickeners, and biobased seed coatings. Additionally, the mono‐ and disodium salts of citric acid were also polymerized with D‐sorbitol in a manner similar to that of the citric acid system. Soluble polymers were synthesized with a residual acid content of 5 mequiv/g of polymer. These materials showed Ca+2‐sequestering ability (up to 0.56 mmol of Ca+2/g of the product). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4259–4267, 2006
GLP SOPs for Equipment Calibration and Maintenance. Part 1: an overview
Authors: Rosa Michelle
Published: May 2006

Writing Standard Operating Procedures (SOPs) for laboratory equipment is viewed as a necessary evil. As a result, many of these documents are not practical or useful to a reader. Writing these documents does not have to be so frustrating. With forethought, careful planning and collaboration, laboratory SOPs can be practical and user‐friendly documents that support continued compliance and create a platform for future growth. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental 35 kV/121 MVA superconducting cable system installed at PUJI substation in China Southern Power Grid
Authors: Xin Ying , Han Zhenghe , Liao Zelong
Published: May 2006

A superconducting cable system, consisting of three 33.5 m, 35 kV/121 MVA cables, six terminations, and a closed cycle liquid nitrogen cooling station, was installed at Puji substation of China Southern Power Grid in March, 2004. Live grid trial operations have been carried out since the completion of the installation and off‐grid testing. Descriptions of the system installation, and results of the testing and trial operation in an over‐a‐year period are presented. The advantages and prospects of applications of superconducting cables are also discussed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Modeling of a buried conductor for an electromagnetic transient simulation
Authors: Ametani Akihiro , Soyama Daigo , Ishibashi Yu , Nagaoka Naoto , Okabe Shigemitsu
Published: May 2006

The paper has proposed a distributed‐line model of a buried bare conductor with horizontal and vertical configuration by assuming an artificial insulator outside of the bare conductor so that the characteristic impedance and the propagation velocity of the buried conductor is evaluated as an insulated conductor (cable) by the cable constants/parameters of the EMTP. A shunt admittance is added to the conductor at every short distance to represent currents flowing into the earth from the original bare conductor. The admittance circuit and the parameters are evaluated either by experimental results or by published references of grounding electrodes. The model circuit has been applied to simulate transient currents and voltages on horizontal and vertical buried conductors, and the simulation results are compared with the measured results. It has been observed that the simulation results of the currents agree satisfactorily with the measured results, but the results of the voltages do not seem satisfactory. The reason for this has been discussed based on the measured results. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Simultaneous measurement of harmonics by a new measuring method
Authors: Miki Toru , Mizutani Amane , Nagaoka Naoto , Ametani Akihiro
Published: May 2006

A harmonic measuring instrument using PICmicro® Microcontroller (PIC) and Phase Locked Loop (PLL), which was discussed in an earlier paper, has been improved. The developed instrument enables a continuous measurement for several days by an additional PIC for power management. A postprocessing program running on a Personal Computer (PC) has also been developed to rearrange the enormous data obtained by multipoint measurements. The developed instrument and the program make the observation of harmonic distribution easier.

Harmonic measurements were carried out in buildings of a university campus with the developed instruments. The results shows that rectifier circuits within a building are sources of the harmonic voltages, while a distortion at another building is caused by a harmonic expansion due to a resonance between a line inductance and capacitances for power compensation. The measured characteristics are also confirmed by numerical simulations using Electro‐Magnetic Transient Program (EMTP). © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
An improved method of voltage utility factor for PWM control of a five‐leg inverter in two induction motor drives
Authors: Oka Kazuo , Nozawa Yusuke , Matsuse Kouki
Published: May 2006

This paper presents an improved method of voltage utility factor (VUF) from 50 to 86.6% for a five‐leg inverter when two induction motors are driven in vector control and in a condition where the frequencies of the two motors are not very different, and the improved method of voltage utility is theoretically shown.

Many modulation methods for the five‐leg inverter have been proposed, but the voltage utility factor is 50% in these methods. The voltage utility factor of the five‐leg inverter is lower than that of the three‐leg inverter as maximum voltage utility factor of the three‐leg inverter is 100%. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
IP controller‐based vector control of induction motor taking core loss into account
Authors: Mannan Mohammad Abdul , Murata Toshiaki , Tamura Junji , Tsuchiya Takeshi
Published: May 2006

This paper presents speed and current control of the induction motor (IM) taking core loss into account based on integral plus proportional (IP) control strategy. The proposed IP controller can overcome the problems (such as overshoot, instability under the variations of parameters and load torque) of the conventional PI controller. The performance of the proposed IP controller and PI controller is compared. The performance comparison of the IP controller and the PI controller is verified by using Matlab/Simulink. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Chaotic phenomena of charged particles in crystal lattices
Authors: Desalvo Agostino , Giannerini Simone , Rosa Rodolfo
Published: May 2006

In this article, we have applied the methods of chaos theory to channeling phenomena of positive charged particles in crystal lattices. In particular, we studied the transition between two ordered types of motion; i.e., motion parallel to a crystal axis (axial channeling) and to a crystal plane (planar channeling), respectively. The transition between these two regimes turns out to occur through an angular range in which the particle motion is highly disordered and the region of phase space spanned by the particle is much larger than the one swept in the two ordered motions. We have evaluated the maximum Lyapunov exponent with the method put forward by Rosenstein et al. [Physica D 65, 117 (1993)] and by Kantz [Phys. Lett. A 185, 77 (1994)]. Moreover, we estimated the correlation dimension by using the Grassberger-Procaccia method. We found that at the transition the system exhibits a very complex behavior showing an exponential divergence of the trajectories corresponding to a positive Lyapunov exponent and a noninteger value of the correlation dimension. These results turn out to be linked to a physical interpretation. The Lyapunov exponents are in agreement with the model by Akhiezer et al. [Phys. Rep. 203, 289 (1991)], based on the equivalence between the ion motion along the crystal plane described as a “string of strings” and the “kicked” rotator. The nonintegral value of the correlation dimension can be explained by the nonconservation of transverse energy at the transition.
Current-driven interactions between voids in metallic interconnect lines and their effects on line electrical resistance
Authors: Cho Jaeseol , Rauf Gungor M. , Maroudas Dimitrios
Published: May 2006

We present a theoretical analysis based on self-consistent numerical simulations of current-driven interactions between voids in metallic thin-film interconnects and the resulting void migration, morphological evolution, and coalescence phenomena. The analysis reveals the complex nature of electromigration-induced void-void interactions, and their implications for the evolution of interconnect line electrical resistance. Most importantly, it is demonstrated that current-driven void-void interaction effects, such as void coalescence, can cause sudden changes in the interconnect line electrical resistance, in qualitative agreement with observations in accelerated electromigration testing experiments.
Current-perpendicular-to-plane magnetoresistance in epitaxial Co2MnSi∕Cr∕Co2MnSi trilayers
Authors: Yakushiji K. , Saito K. , Mitani S. , Takanashi K. , Takahashi Y. K. , Hono K.
Published: May 2006

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of the multilayer thin film using a full-Heusler Co2MnSi (CMS) phase as ferromagnetic electrodes has been investigated. A multilayer of Cr buffer (10nm)∕CMS (50nm)∕Cr spacer (3nm)∕CMS (10nm)∕Cr cap (3nm) was grown on a MgO(100) substrate. The 50nm thick CMS layer which was deposited on the Cr buffer at 573K was epitaxially grown and had an L21 structure. The resistance change-area product (ΔRA) at room temperature was 19mΩμm2, which is one order of magnitude larger than those in previously reported trilayer systems, resulting in the MR ratio of 2.4%. A possible origin of the enhanced ΔRA is considered to be the large spin polarization in a high-quality L21 CMS film.
Thermophysical properties of a Cu46Zr42Al7Y5 bulk metallic glass-forming liquid
Authors: Fan G. J. , Li J. J. Z. , Rhim Won-Kyu , Qiao D. C. , Choo H. , Liaw P. K. , Johnson W. L.
Published: May 2006

The thermophysical properties, including the specific volume V, the surface tension σ, and the viscosity η, of a Cu46Zr42Al7Y5 bulk metallic glass in the molten state were investigated using a containerless high-temperature high-vacuum electrostatic levitation technique. The viscosity measurements indicate that the Cu46Zr42Al7Y5 alloy exhibits an intermediate fragility with the fragility index m=49.
Novel tungsten oxide microneedles with nanosized tips
Authors: He Yuehui , Wang Shiliang , Huang Baiyun , Liu C. T. , Liaw P. K.
Published: May 2006

In this study, we have developed an innovative processing technique to synthesize oxide microneedles with nanotips by in situ vapor deposition. Single-crystal needles of tungsten oxide W18O49, with their root diameter of ∼1μm and tip diameter of several nanometers, are successfully fabricated by this low-cost technique. Because of their sharp tips and excellent field emission property, the synthesized microneedles have the great potential to be used as tips for many micro- and nanodevices. Furthermore, this technique provides a basis to produce other oxide microneedles for functional and structural use.
Effects of the fire retardant Phos-Chek on vegetation in eastern Australian heathlands
Authors: Bell Tina , Tolhurst Kevin , Wouters Michael
Published: May 2006

The effects of the fire retardant Phos-Chek D75R on species composition, survival and growth of eastern Australian heathland vegetation are described. Two sites in Victoria were selected, Victoria Valley in the Grampian Ranges and Marlo in East Gippsland. Both areas supported heathland vegetation that was long, unburnt and relatively undisturbed. Plots were subjected to single applications of increasing concentrations of retardant (0.5, 1.0 and 1.5 L fire retardant m−2) or no additional fire retardant (‘Control’ and ‘Water only’ treatments). A single application of Phos-Chek did not appear to significantly change species composition or projected foliage cover of the major life forms of native heathland vegetation. However, it did cause whole plant and shoot death of key species Allocasuarina paludosa, Banksia marginata, Leptospermum continentale and L. myrsinoides, and was observed to affect other species. The fertilising effect of the fire retardant generally increased shoot growth of the key species but did not significantly increase the overall height of these species. The application of fire retardant enhanced weed invasion, particularly when supplied at higher concentrations. A number of research recommendations are made from this preliminary investigation.
Combustion properties of Bromus tectorum L.: influence of ecotype and growth under four CO2 concentrations
Authors: Blank Robert R. , White Robert H. , Ziska Lewis H.
Published: May 2006

We grew from seed the exotic invasive annual grass Bromus tectorum L., collected from three elevation ecotypes in northern Nevada, USA. Plants were exposed to four CO2 atmosphere concentrations: 270, 320, 370, and 420 μmol mol–1. After harvest on day 87, above-ground tissue was milled, conditioned to 30% relative humidity, and combustion properties were measured using a cone calorimeter. Plants exposed to 270 μmol mol–1 CO2 had significantly less total heat released than plants exposed to higher CO2 concentrations. Total heat released was least for the low-elevation ecotype, statistically similar for the mid-elevation ecotype, and significantly increased for the high-elevation ecotype. Plant attributes that significantly correlated with heat release included tissue concentrations of lignin, glucan, xylan, potassium, calcium, and manganese. The data suggest that a decline in tissue concentrations of lignin, xylan, and mineral constituents, as CO2 concentration increases from 270 μmol mol–1 to higher levels, affects the combustion process. We suspect that as tissue concentrations of lignin and inorganics decline, char formation decreases, thereby allowing more complete combustion. Changes in combustion parameters of B. tectorum induced by different CO2 concentrations and elevation ecotype may be a strong consideration to understanding fire behaviors of the past, present, and future.
NUCLEAR GENE CONTROL OF MITOCHONDRIAL MALIC DEHYDROGENASE IN MAIZE
Authors: Longo Giovanna P. , Scandalios John G.
Published: May 2006

The isozymes of malic dehydrogenase (MDH) of maize have been separated by starch gel zone electrophoresis. The MDH isozyme pattern was the same in different organs and developmental stages. The subcellular distribution of the different isozymes was established by means of differential centrifugation. The MDH isozymes were found to be differentially distributed in the cytoplasm, the mitochondria, and the glyoxysomes. The latter proved the only exception to the pattern constancy among organs insofar as they are present only in the scutella. Among several inbred maize strains examined, only variants of the mitochondrial isozymes were found. Crosses between strains with different isozyme patterns gave Mendelian inheritance: thus, these mitochondrial isozymes are under nuclear-gene control.
INCORPORATION OF BRANCHED-CHAIN FATTY ACIDS INTO MYXOVIRUSES
Authors: Blough Herbert A. , Tiffany John M.
Published: May 2006

The incorporation of free fatty acids into myxoviruses was shown, using branched-chain fatty acids as molecular markers. The presence of isostearic or phytanic acid was detected by gas-liquid chromatography in the phospholipid fraction of the A
0
/PR8/34 strain of influenza virus. Uptake of free fatty acids into the virus varied from 8 to 11 per cent and was accompanied by a shift in the fatty acid profile. Infected allantoic fluids from eggs treated with branched-chain acids possessed higher hemagglutinin activity when compared to fluids infected under normal conditions. Attempts to detect branched-chain acids in Sendai virus were unsuccessful. Shifts in acyl chain composition persisted after three passages of modified viruses in the absence of branched-chain acids. Force-area curves at an air-water interface revealed the cross-sectional area of branched-chain acids to be greater than their straight-chain homologs. It is suggested that hydrophobic interactions can alter the configuration of envelope proteins. Such changes may have an important role in the selection of fragments of influenza viral genome and can conceivably alter viral genotype.
THE USE OF NUCLEAR MAGNETIC RESONANCE TO DESCRIBE RELATIVE MODES OF BINDING TO LYSOZYME OF HOMOLOGOUS INHIBITORS AND RELATED SUBSTRATES
Authors: Raftery M. A. , Dahlquist F. W. , Parsons S. M. , Wolcott R. G.
Published: May 2006

Proton magnetic resonance has been used to study the association of inhibitors and substrates with hen egg-white lysozyme. Changes in chemical shift, due to association, of acetamido methyl group resonances of the small molecules have been quantitated. This has allowed definition of magnetic parameters for three contiguous binding subsites on the enzyme surface. The relative modes of occupancy of these sites by
N
-acetyl-D-glucosamine (NAG), chitobiose, chitotriose, their methyl glycosides, and chitotetraose have been delineated. In addition, the binding to these sites of
N
-acetyl-D-muramic acid (NAM) and a cell-wall disaccharide, NAG-NAM, have been studied. There is good, although not complete, agreement between the results obtained and X-ray analysis studies of the binding of some of these inhibitors to crystalline lysozyme. Binding of synthetic substracts, such as
p
-nitrophenyl-2-acetamido-4-O-(2-acetamido-2-deoxy-β-D -glucopyranosyl)-β-D-glucopyranoside (NAG-Gluc-ϕNO
2
), has also been studied by the magnetic resonance technique described.
ELECTRON SPIN RESONANCE OF AN IRRADIATED SINGLE CRYSTAL OF L-TYROSINE-HCL
Authors: Fasanella Edwin L. , Gordy Walter
Published: May 2006

Analysis of the electron spin resonance (ESR) of a γ-irradiated single crystal of L-tyrosine-HCl reveals a free radical formed by loss of an H from the hydroxyl group attached to the ring. Principal
g
values of the radical are

g
x

= 2.0023 ± 0.0005,

g
y

= 2.0067 ± 0.0005, and

g
z

= 2.0045 ± 0.0005, with

g
x

perpendicular to the plane of the ring and

g
y

along the CO bond to the ring. Analysis of the hyperfine structure of the spectra shows electron spin density on C
(2)
and C
(6)
to be 0.24 and on C
(4)
to be 0.32. Corresponding spin densities calculated from molecular orbital theory are 0.26 and 0.31, respectively.
GENE EXPRESSION IN INTERSPECIFIC HYBRIDS, II. RNA SYNTHESIS IN THE LETHAL CROSS
Arbacia lixula
[unk] ×
Paracentrotus lividus
[unk]
Authors: Denis H. , Brachet J.
Published: May 2006

All types of RNA are actively synthesized by the lethal hybrid obtained by fertilizing the eggs of the sea urchin
Paracentrotus lividus
with the sperm of another sea urchin species,
Arbacia lixula
. DNA-like RNA and ribosomal RNA seem to be less stable in hybrids than in normal
A. lixula
and
P. lividus
embryos.

Labeled RNA's from
A. lixula
and
P. lividus
were found to hybridize about 2.5 times as well with DNA of their own species as with DNA of the other species. RNA from the interspecific hybrid hybridized from 1.6 times to twice as well with
A. lixula
DNA as with
P. lividus
DNA, although the hybrid embryos were previously shown
5
to contain more DNA of maternal than of paternal type. Transcription of the paternal (foreign) genome seems therefore to be favored in some way in the interspecific hybrid.
A MUTANT OF YEAST APPARENTLY DEFECTIVE IN THE INITIATION OF PROTEIN SYNTHESIS
Authors: Hartwell Leland H. , McLaughlin Calvin S.
Published: May 2006

A temperature-sensitive mutant of yeast, ts
-
187, which is apparently unable to initiate the synthesis of new polypeptide chains after a short incubation at the restrictive temperature, is described. The existence of this mutant demonstrates that in eucaryotic cells, as in procaryotic cells, there are processes unique to the initiation of polypeptide chains.
A FLUORESCENCE PROBE OF ENERGY-DEPENDENT STRUCTURE CHANGES IN FRAGMENTED MEMBRANES
Authors: Azzi A. , Chance B. , Radda G. K. , Lee C. P.
Published: May 2006

The reaction of the fluorochrome, 8-anilino-1-naphthalene-sulfonic acid (ANS), with fragmented membranes from beef heart mitochondria has been studied. ANS fluorescence is found to be enhanced 25-fold on binding to the membrane fragments in the absence of energy conservation, and this enhancement is increased to 35-fold in the membrane energized by substrate plux oxygen. The fluorescence of bound ANS depends upon the energy state of the membrane fragments, as indicated by the effects of ATP, substrates of the respiratory chain, oligomycin, and uncouplers. It is concluded that the changes of ANS fluorescence indicate structural changes of the mitochondrial membrane associated with energy conservation. The time course of energization is readily followed by ANS, and has a half-time of two seconds at 26°.
PROTEROZOIC EUCARYOTES FROM EASTERN CALIFORNIA
Authors: Cloud P. E. , Licari G. R. , Wright L. A. , Troxel B. W.
Published: May 2006

Both procaryotic and eucaryotic nannofossils occur in chert from the upper Beck Spring Dolomite (Pahrump Group) in northeastern San Bernardino County, California. These fossils include the oldest reasonably certain records to date of chlorophycean and chrysophycean algae, and hence of the eucaryotic or mitosing cell. Associated with these are cyanophycean procaryotes of still more ancient affinities. Indirect radiometric evidence implies an age of 1.2 to 1.4 aeons (1.2 to 1.4 × 10
9
years) for the enclosing rocks. Associated stromatolites are consistent with such an age assignment.
MUTANTS IN
Escherichia coli
RIBOSOMES: A NEW SELECTION
Authors: Phillips S. L. , Schlessinger D. , Apirion D.
Published: May 2006

Only a few ribosome genes have been identified. Increasing the available kinds of ribosome mutants would thus facilitate the analysis of specification and function of the organelle. In an attempt to reveal a number of ribosome genes, we sought mutants that could not form functional ribosomes at a nonpermissive temperature (43°). Cells were depleted of ribosomes by nutrient starvation at 43°, and 98 strains that could not recover from the starvation were then isolated. Of these 98, many satisfied auxiliary criteria for ribosome mutants; 23 showed increased sensitivity to antibiotics that affect ribosome function; and 8 of 20 representative strains had crude extracts more temperature sensitive than that of the parental strain when assayed for polyphenylalanine formation in the presence of excess soluble enzymes (
S
100) of the parental strain. In further tests with two of these strains, the temperature sensitivity of the washed ribosomes, compared to that of the parental strain, was confirmed.

The variety of phenotypes among the mutants suggests that this selection is capable of revealing mutants in many ribosome genes.
CRYSTALLIZATION OF DNA FROM DILUTE SOLUTION
Authors: Giannoni G. , Padden F. J. , Keith H. D.
Published: May 2006

Hexagonal platelet crystals about 1 μ across and about 150 Å thick have been precipitated by the addition of ethanol to solutions of ultrasonically degraded, salmon sperm DNA in sodium cacodylate buffer. X-ray powder diffraction patterns from concentrated slurries of these crystals in mother liquor show intense rings at 23.9 Å and at about 3.4 Å; the former arise from lateral packing and the latter from an axial periodicity of the DNA helix. Evidence is presented to indicate that native DNA helices crystallize by chain folding and that no irreversible denaturation results from the crystallization process.
“RESCUED” SV40: INCREASED TRANSFORMING EFFICIENCY IN MOUSE AND HUMAN CELLS
Authors: Todaro George J. , Takemoto Kenneth K.
Published: May 2006

Plaque-size mutants of simian virus 40 (SV40) have been characterized with respect to their ability to transform mouse and human cells
in vitro
. Large plaque mutants of SV40 were extremely inefficient at transforming mouse or human cells, requiring approximately 50 times more infectious particles per transformation event than did the small plaque mutants. The minute plaque SV40 was the most efficient, requiring less than 10
3
plaque-forming units per transformation in mouse Balb/3T3 cells and only 1.5 × 10
4
plaque-forming units per transformation unit in the “susceptible” human strains. Both small and minute plaque virus were unable to help the large plaque virus to transform. Virus “rescued” from transformed 3T3 cells by cocultivation with monkey kidney cells was more efficient at transformation than the parental type. The increased efficiency could be shown for each plaque type and in human as well as in mouse cells. The property of “high efficiency transformation” is stable through at least two passages in monkey kidney cells.
SINGULAR INTEGRALS AND THE PRINCIPAL SERIES
Authors: Knapp A. W. , Stein E. M.
Published: May 2006

The
L
2
theory of singular integral operators on nilpotent Lie groups is studied, extending known results for IR

n

. The intertwining operators for the representations of the simple Lie groups of real rank one turn out to be of this type. As a result we determine which representations of the principal series of these groups are irreducible.
ADENYL CYCLASE AND HORMONE ACTION, I. EFFECTS OF ADRENOCORTICOTROPIC HORMONE, GLUCAGON, AND EPINEPHRINE ON THE PLASMA MEMBRANE OF RAT FAT CELLS
Authors: Bär H. P. , Hechter O.
Published: May 2006

A large number of hormones, of diverse molecular structure, evoke characteristic responses in target cells via the intermediary 3′,5′-AMP, the specificity of hormone action upon cell type being achieved by selective stimulation of adenyl cyclase. In the fat cells of rat adipose tissue, adenyl cyclase is stimulated by a number of hormones of disparate molecular structure, posing the question whether this cell type posesses multiple cyclase systems with distinctive specificities for individual hormones, or a single cyclase with broad specificity to a variety of hormones.

Studies of the stimulatory effects of adenocorticotropin, glucagon, and epinephrine upon the adenyl cyclase of the rat fat cell “ghosts” (plasma membrane sacs) have shown that distinctive selectivity sites for each of these hormones can be differentiated. The β-adrenergic blocking agent Kö 592 abolished the stimulatory effect of epinephrine without influencing adenocorticotropin or glucagon; Ca was required for adenocorticotropin action, but not for glucagon or epinephrine. Dose-response curves show that the affinity of hormones to the cyclase system was in the order: glucagon > adenocorticotropin ≫ epinephrine; the magnitude of cyclase activation by maximal doses of hormones had a reversed order. Combinations of maximal doses of hormones failed to produce additive stimulation. The results show that in the membrane of the fat cell a single catalytic unit of adenyl cyclase is coupled to distinctive selectivity sites for three lipolytic hormones.
IDENTIFICATION OF THE POLYPEPTIDE CHAINS INVOLVED IN THE CROSS-LINKING OF FIBRIN
Authors: Chen Renné , Doolittle Russell F.
Published: May 2006

The stabilization of fibrin clots by activated factor XIII involves two different sets of cross-linked chains. In one case (type I) two γ-chains are linked to each other, indicating that γ-chains have both donor (suitable lysyl-) and acceptor (suitable glutaminyl-) functions. A second system (type II) consists of a γ-chain linked to an α-chain. Experiments with a substitute donor (glycine ethylester) indicate that only γ-chains have enzyme-accessible acceptor sites, suggesting that α-chain participation is limited to lysyl side chains. A model molecular arrangement for fibrin has been suggested which accommodates all the data.
INTERACTIONS OF HORMONAL STEROIDS WITH NUCLEIC ACIDS, I. A SPECIFIC REQUIREMENT FOR GUANINE
Authors: Cohen Paul , Kidson Chev
Published: May 2006

Under equilibrium conditions testosterone, progesterone, estradiol, and corticosterone bind to denatured but not to native DNA. Among synthetic polynucleotides, steroids bind only to guanine containing polymers:poly dG, poly G, poly UG, poly AG, and “denatured” poly dG:dC; however, they do not bind to rRNA, sRNA, TMV-RNA, poly CG, or native poly dG:dC. These data indicate a preferential affinity for guanine residues and for single-stranded regions of polynucleotides. That different functional groups of the purine are involved in the associations with different steroids is indicated by the observation that only estradiol binds to poly I. Restrictions are also imposed by structural attributes of the steroids: an α-substitution at C-17 reduces binding, polyhydroxylated steroids bind poorly or not at all.
ROLE OF CHROMATIN IN ESTROGEN ACTION IN THE UTERUS, II. HORMONE-INDUCED SYNTHESIS OF NONHISTONE ACIDIC PROTEINS WHICH RESTORE HISTONE-INHIBITED DNA-DEPENDENT RNA SYNTHESIS
Authors: Teng Ching-Sung , Hamilton Terrell H.
Published: May 2006

Nonhistone acidic proteins were isolated, by equilibrium density centrifugation in 4
M
cesium chloride, from the chromatin isolated and purified from the uterus of the ovariectomized rat or from calf endometrium. Evidence is presented to show (1) that arginine-rich histones are more effective inhibitors of chromatin-directed RNA synthesis
in vitor
than lysine-rich histones, (2) that the nonhistone acidic proteins of chromatin do not inhibit the synthesis of RNA directed by chromatin
in vitro
, (3) that added nonhistone acidic chromatin proteins effect a restoration of histone-inhibited RNA synthesis directed by chromatin
in vitro
, and (4) that the synthesis of nonhistone acidic chromatin proteins is under estrogen control in the uterus, but not in the liver. It is concluded that a major feature of the early action of estrogen in the uterus of the ovariectomized rat is the stimulation of synthesis and the accumulation in the interphase chromosomes of nonhistone acidic proteins which counter the inhibitory effect of histone on transcription by RNA polymerase. Presumably this would permit more and perhaps a new synthesis of RNA programmed for transport to the cytoplasm.
IMMUNOLOGICAL REACTIVITY OF PURIFIED HUMAN PARATHYROID HORMONE
Authors: O'Riordan J. L. H. , Aurbach G. D. , Potts J. T.
Published: May 2006

Immunological differences between human and bovine parathyroid hormones are detected with highly purified preparations of each hormone and several antisera produced against bovine parathyroid hormone. The immunological differences found show the necessity for using a reference preparation of human hormone in assays for parathyroid hormone in human serum.
TWO DEOXYRIBONUCLEASE ACTIVITIES WITHIN PURIFIED VACCINIA VIRUS
Authors: Pogo Beatriz G. T. , Dales Samuel
Published: May 2006

Two DNases, both hydrolizing single-stranded DNA, were identified within highly purified particles of vaccinia virus. One of these, active optimally at pH 5.0, is an exonuclease and the other, most active at pH 7.8, is an endonuclease. These two activities were localized more specifically within the virus cores. Upon elimination of the envelopes, followed by removal of the lateral bodies of vaccinia, both DNases were activated, suggesting that a specific inhibitor of these enzymes may be present in the lateral bodies.
BIOCHEMICAL EVIDENCE FOR INDUCTION BY POLYOMA VIRUS OF REPLICATION OF THE CHROMOSOMES OF MOUSE KIDNEY CELLS
Authors: Hancock R. , Weil R.
Published: May 2006

It was shown earlier that in cultures of contact-inhibited mouse kidney cells infection with polyoma virus induces replication of the chromosomal DNA. In this paper we present evidence, based on analyses of isolated chromatin, that, parallel with and as a consequence of the virus-induced synthesis of cellular DNA, the chromosomal proteins are synthesized in the proportions characteristic of normal chromosome replication. These results are compatible with the hypothesis that polyoma virus activates (or derepresses) a regulatory system of the host cell which controls initiation of chromosome replication.
CRYSTALLIZATION OF A MULTIENZYME COMPLEX: FATTY ACID SYNTHETASE FROM YEAST
Authors: Oesterhelt D. , Bauer H. , Lynen F.
Published: May 2006

The crystallization of purified fatty acid synthetase from yeast is facilitated by seeding techniques. The first seed crystals appeared as particles with almost negligible enzymatic activity in a solution that had been left at 4°C for 15 months. Subsequently, the crystallization time has been reduced to two days, and the crystals now isolated have retained their full enzymatic activity. The loss of synthetase activity that can result from prolonged exposure during crystallization is attributable specifically to damage of the enzyme component responsible for condensation activity. Crystalline synthetase is identical to purified but noncrystalline synthetase by all criteria so far examined.
DEACYLATED TRNA
Phe
BINDING TO A RETICULOCYTE RIBOSOMAL SITE FOR THE INITIATION OF POLYPHENYLALANINE SYNTHESIS
Authors: Culp William J. , McKeehan Wallace L. , Hardesty Boyd
Published: May 2006

The initiation of polyphenylalanine synthesis at low MgCl
2
concentration in the reticulocyte transfer system has been found to have a stringent requirement for deacylated tRNA
Phe
. An initial poly-U-directed complex between deacylated tRNA
Phe
and ribosomes is formed. The onset of polyphenylalanine synthesis causes the rapid release of tRNA
Phe
from the complex. Thermal dissociation studies indicate that deacylated tRNA
Phe
and phenylalanyl-tRNA are bound to the same ribosomes. A total of three ribosomal tRNA binding sites is indicated.
SUSTAINED EFFECTS OF BRIEF DAILY STRESS (FIGHTING) UPON BRAIN AND ADRENAL CATECHOLAMINES AND ADRENAL, SPLEEN, AND HEART WEIGHTS OF MICE
Authors: Welch Bruce L. , Welch Annemarie S.
Published: May 2006

Male white Swiss mice that had previously been made aggressive by several weeks of individual housing were allowed to fight for 5 to 10 minutes each day for 5, 10, or 14 consecutive days; fighting caused a marked enlargement of their adrenals, spleens, and hearts, and a large increase in adrenal catecholamines; brain catecholamines were slightly increased. Long-term group caging, under conditions where the mice did not fight, caused changes that were directionally the same but of smaller magnitude. Similar sociophysiological influences may be important in natural populations. Fighting mice, used under well-defined and closely controlled conditions, may be useful for studying normal mechanisms of neuroendocrine adaptation and control, and, possibly, for studying some forms of hypertension and cardiovascular-renal disease.
ORIENTATION AND MOTION OF AMPHIPHILIC SPIN LABELS IN MEMBRANES
Authors: Hubbell Wayne L. , McConnell Harden M.
Published: May 2006

The paramagnetic resonance spectra of N-oxyl-4′,′-dimethyloxazolidine derivatives of 12-ketostearic acid, 5-ketostearic acid, 5-ketotricosanoic acid, and 5α-androstan-3-one-17β-ol have been observed in sonicated phospholipid dispersions, the walking-leg nerve fibers of
Homarus americanus
, and in erythrocytes oriented by hydrodynamic shear. The preferred orientation of these spin labels in the nerve and erythrocyte membranes is one in which the long amphiphilic axis is perpendicular to the membrane surface. The resonance spectra indicate that these labels in the nerve fiber are bound to a lipid bilayer very similar to that found in the sonicated phospholipid dispersion, whereas any lipid bilayer in the erythrocyte must be much more rigid.
THE PROCESS OF INFECTION WITH BACTERIOPHAGE ϕX174, XXX. REPLICATION OF DOUBLE-STRANDED ϕX DNA
Authors: Knippers Rolf , Whalley J. Millar , Sinsheimer Robert L.
Published: May 2006

Intermediates involved in the replication of double-stranded ϕX174 RF DNA have been identified and partially characterized. Analysis of pulselabeled RF DNA suggests that the synthesis of progeny RF molecules involves, in part, the addition of nucleotides to linear complementary strands on a circular parental strand as template, so as to produce intermediate DNA strands of greater than viral length. Electron microscopy reveals DNA rings with “tails” and “double rings,” which could be the intermediate structures. A model is postulated for the replication process.
THE HIGH-ENERGY LIGHT ACTION CONTROLLING PLANT RESPONSES AND DEVELOPMENT
Authors: Borthwick H. A. , Hendricks S. B. , Schneider M. J. , Taylorson R. B. , Toole V. K.
Published: May 2006

Evidence is advanced for a network of three photoreactions and five dark reactions in control of plant growth and development by phytochrome.
QUANTITATIVE STUDY OF CLINAL VARIATION IN
Juniperus virginiana
USING TERPENOID DATA
Authors: Flake Robert H. , Rudloff Ernst Von , Turner B. L.
Published: May 2006

Nine populations of
Juniperus virginiana
were sampled at approximately 150-mile intervals along a 1500-mile transect from northeastern Texas to Washington, D.C. Individual plants were examined for terpenoids by gas liquid chromatography and the resulting data analyzed by numerical classification methods using characters weighted according to their estimated variance in the natural populations.

The results of the analysis show that these populations of
J. virginiana
cluster clinally from northeast to southwest, the more homogeneous populations occurring in the Appalachian region of North America; the more divergent populations found in progressively more distant regions, as measured along the transect from the northeast toward the southwest. No biochemical evidence could be found to support the hypothesis that hybridization with
J. ashei
might be causing this variability, as had been widely supposed previously.
A MECHANISM FOR GENETIC RECOMBINATION GENERATING ONE PARENT AND ONE RECOMBINANT
Authors: Boon Thierry , Zinder Norton D.
Published: May 2006

A mechanism is proposed for generating one parental and one recombinant genome in a single recombination event between two DNA molecules. Three stages of the event are described: initiation, replication, and return. Initiation requires breakage and joining of strands. Replication proceeds through a biparental “replication fork” generated in initiation. Return also involves breakage and joining of strands. Some of the implications of such a mechanism for genetic recombination are discussed.
ISOLATION OF β-GLUCAN SYNTHETASE PARTICLES FROM PLANT CELLS AND IDENTIFICATION WITH GOLGI MEMBRANES
Authors: Ray Peter M. , Shininger Terry L. , Ray Margery M.
Published: May 2006

A variety of particle-bound synthetases that use sugar nucleotides as glycosyl donors for the formation of polysaccharides similar to those of the cell wall have been demonstrated in mung beans and other plant tissues,
1
but the particles in question have not been previously identified.
2, 3
The polysaccharide synthetase particles from peas that form mainly β-1,4-glucan from UDPG and GDPG have now been separated from other cell particles by combinations of velocity and isopycnic density gradient centrifugation. The particles have an effective density of about 1.15 gm cm
-3
, exhibit latent nucleoside diphosphatase activity upon IDP, UDP, GDP, and to a lesser extent upon ADP, and also possess acid phosphatase and weak ATPase activity. The isolated synthetase particles consist of somewhat condensed Golgi dictyosomes and free dictyosomal membranes bearing vesicles. It is concluded that the synthetase particles are Golgi membranes. The nucleoside diphosphatase activity of these particles may represent inactivated polysaccharide synthetase.
ACTIVE CENTER FRACTIONS FROM
Rhodopseudomonas spheroides
STRAIN Y. (DE KLERK)
Authors: Jolchine G. , Reiss-Husson F. , Kamen M. D.
Published: May 2006

Active center fractions have been prepared from
Rhodopseudomonas spheroides
strain Y. (de Klerk) using the cationic detergent cetyltrimethyl ammonium bromide and light particles from bacteria grown in two media differing in iron content. Spectral properties and composition of the fractions are presented.