bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiwalled Carbon Nanotubes Resist Intercalation Whereas Pyrolytic Graphite Can Exfoliate in Propylene Carbonate: Electroanalysis Without the Deleterious Effects of Intercalation for the Detection of Ammonia
Authors: Ji Xiaobo , Banks Craig E. , Hu Gang , Crossley Alison , Compton Richard G.
Published: October 2006

A generic approach is presented allowing the sensing of electroactive species at carbon based electrodes in otherwise potentially intercalating media. Graphite electrodes are known to suffer intercalation leading to exfoliation in propylene carbonate solution containing tetra‐n‐butylammonium perchlorate as supporting electrolyte. However, we report contrasting behaviour at bamboo multiwalled carbon nanotubes, where intercalation/exfoliation does not occur, so allowing useful electroanalytical measurements to be made, in particular for the amperometric determination of ammonia.
Adaptive Euler simulations of airfoil–vortex interaction
Authors: Tang Lei , Baeder James D.
Published: October 2006

A grid redistribution method is used together with an improved spatially third‐order accurate Euler solver to improve the accuracy of direct Euler simulations of airfoil–vortex interaction. The presented numerical results of two airfoil–vortex interaction cases indicate that with combination of the two methods, the numerical diffusion of vorticity inherent in the direct Euler simulations is drastically reduced without increasing the number of grid points. With some extra works due to grid redistribution, the predicted vortex structure is well preserved after a long convection and much sharper acoustic wave front resulting from airfoil–vortex interaction is captured. Copyright © 2006 John Wiley & Sons, Ltd.
Preoperative evaluation of the hepatic vascular anatomy in living liver donors: Comparison of CT angiography and MR angiography
Authors: Lee Min Woo , Lee Jeong Min , Lee Jae Young , Kim Se Hyung , Park Eun‐Ah , Han Joon Koo , Kim Young Jun , Shin Kyung‐Sook , Suh Kyung‐Suk , Choi Byung Ihn
Published: October 2006

Purpose

To compare the diagnostic performance of CT angiography (CTA) and MR angiography (MRA) for preoperative hepatic vascular evaluation in living liver donors.

Materials and Methods

Twenty‐eight living donor candidates underwent preoperative CTA and MRA. Two blinded radiologists evaluated the anatomic types of the hepatic artery (HA) and portal vein (PV), and the number of aberrant hepatic veins (HVs) on both CTA and MRA, independently. Four grades of confidence levels were used to indicate the clarity of depiction of the HA and PV. Surgical findings were used as a standard of reference.

Results

For determining the anatomic types of the HA and PV, and the number of aberrant HVs, CTA and MRA did not significantly differ in terms of accuracy ([89%, 96%, and 68% on CTA] vs. [86%, 93%, and 68% on MRA] for reader 1, P > 0.05; and [93%, 100%, and 86% on CTA] vs. [89%, 93%, and 79% on MRA] for reader 2, P > 0.05). Confidence for the depiction of major branches of HA and PV did not differ between CTA and MRA, except for a better depiction of the left HA (LHA) on CTA (P < 0.05)

Conclusion

In living donor candidates, both CTA and MRA can provide a complete evaluation of the hepatic vascular anatomy. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Boundary conditions of the impact of a hypervigilant coping style on the subjective decision‐making experience
Authors: Kozup John C. , Creyer Elizabeth H.
Published: October 2006

Two experiments explored how characteristics of the task environment and the consumer's propensity to a use a hypervigilant coping style interacted to influence ratings of perceived information amount, choice difficulty, decision‐process–related satisfaction,choice deferral, and the desire for decision assistance. Results indicate a series of main effects of time pressure on the dependent measures across two different choice scenarios. In addition, the findings suggest that a propensity to use a hypervigilant coping style seems to have little influence on the subjective decision‐making experience. Theoretically, this research establishes boundary conditions under which decision‐process–related thoughts, feelings, and behaviors are not likely to be influenced by coping style, and extends prior work on the determinants of choice deferral and the desire for decision assistance. © 2006 Wiley Periodicals, Inc.
Exciton luminescence of boron nitride nanotubes and nano‐arches
Authors: Berzina B. , Trinkler L. , Korsak V. , Krutohvostov R. , Carroll D. L. , Ucer K. B. , Williams R. T.
Published: October 2006

We report photoluminescence (PL) and PL‐excitation spectroscopy of BN nanotubes (nt‐BN) mixed with some residual hexagonal crystalline (h‐BN) starting material, and of pure h‐BN microcrystalline powder. The nanotube phase exhibits a broad‐band PL near 380 nm, in agreement with a published report of cathodoluminescence from a sample comprising >90% nanotubes. This emission is almost 3 eV lower in energy than unrelaxed exciton states found in recent all‐electron theories of nt‐BN and h‐BN and about 1.4 eV lower than the lowest (perturbed dark?) exciton seen in absorption of nt‐BN. This may suggest that excitons in nt‐BN vibrationally relax to self‐trapped states before emitting, a path found in many wide‐gap solids, especially in quasi‐1‐dimensional forms. Exciton emission from bulk single‐crystal h‐BN has been shown to occur from vibrationally unrelaxed (free‐exciton) states. We suggest a hypothesis in which known nano‐arch reconstructions on the surface of h‐BN may provide the low‐dimensional environment to make exciton self‐trapping on the surfaces of h‐BN likely. This allows consistent interpretaton of the surface‐related 380 nm emission from h‐BN powder within a half‐nanotube self‐trapped exciton hypo‐ thesis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherent destruction of the current through molecular wires using short laser pulses
Authors: Kleinekathöfer Ulrich , Li Guang Qi , Welack Sven , Schreiber Michael
Published: October 2006

A molecular wire coupled to two electron reservoirs is investigated within a tight‐binding approach including spin and Coulomb interaction. Under the assumption of weak coupling to the electron reservoirs a quantum master equation can be derived for the electron transport through the wire. Motivated by the phenomenon of coherent destruction of tunneling for monochromatic laser fields, the influence of Gaussian laser pulses on the transport through the wires is studied. For situations in which the maximum amplitude of the electric field fulfills the conditions for the destructive quantum effect the average current through the system can be suppressed. Turning on the electron correlation does not destroy the suppression of the current by the laser. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symbol error rate calculation and data pre‐distortion for 16‐QAM transmission over nonlinear memoryless satellite channels
Authors: Alasady Hisham , Ibnkahla Mohamed , Rahman Quazi
Published: October 2006

This paper presents a simplified mathematical approach to evaluate the performance of any given circular constellation of 16‐level quadrature amplitude modulation (16‐QAM) in terms of symbol error rate (SER). Following this approach, with the aim to work with memoryless nonlinear satellite channels, a model is derived as a generalized form for both linear and nonlinear channels in the presence of down link additive white Gaussian noise (AWGN). The analysis provides means to calculate the optimal ring ratio (RR) and phase difference (PD) for several possible candidates of 16‐QAM circular constellations. The effects of RR and PD on the SER performance are investigated in the analysis. To overcome the nonlinear distortion, data pre‐distortion is taken into account in the study. The paper gives a general procedure for data pre‐distortion implementation for all circular 16‐QAM constellations. The analytical formulation has been extended for total degradation (TD) performance measure as a function of input back‐off (IBO) of the nonlinear amplifier. A SER performance‐comparison between different constellations for 16‐QAM systems has also been presented in this paper. The analytical results are validated by simulation. Copyright © 2006 John Wiley & Sons, Ltd.
Toward a model for the bulking and debulking of lahars
Authors: Fagents Sarah A. , Baloga Stephen M.
Published: October 2006

The incorporation and loss of material (sediments or water) during the advance of a lahar can significantly influence the advance rate, mobility, rheology, and inundation limits of the flow, and therefore these processes have consequences for destructive potential. We have developed a theoretical treatment based on the conservation of flow volume and mass to describe the influence of such processes on the depth, discharge, and density during transit. We apply our model to a common scenario of lahar generation and evolution: the formation of an initially dilute flow by catastrophic breaching or ejection of a volcanic summit crater lake, followed by bulking due to incorporation of substrate materials, and later debulking due to sediment deposition. The key features of our model are time dependence and the inclusion of two terms describing the influx or efflux of sediments to or from the flow. For lahars triggered by crater lake water, we derive the time evolution of flow behavior for comparison with the well‐documented 1953 lahar of Mount Ruapehu, New Zealand. Our model demonstrates the importance of these processes on observable quantities such as flow depth, density, and deposit profiles, hydrograph evolution, and transformations between rheologic/density regimes.
Parity-dependent rotational rainbows in D2–NO and He–NO differential collision cross sections
Authors: Gijsbertsen Arjan , Linnartz Harold , Stolte Steven
Published: October 2006

The (j′,Ω¯′,ϵ′) dependent differential collision cross sections of D2 with fully state selected (j=1∕2, Ω=1∕2, ϵ=−1) NO have been determined at a collision energy of about 550cm−1. The collisionally excited NO molecules are detected by (1+1′) resonance enhanced multiphoton ionization combined using velocity-mapped ion-imaging. The results are compared to He–NO scattering results and tend to be more forward scattered for the same final rotational state. Both for collisions of the atomic He and the molecular D2 with NO, scattering into pairs of rotational states with the same value of n=j′−ϵϵ′∕2 yields the same angular dependence of the cross section. This “parity propensity rule” remains present both for spin-orbit conserving and spin-orbit changing transitions. The maxima in the differential cross sections—that reflect rotational rainbows—have been extracted from the D2–NO and the He–NO differential cross sections. These maxima are found to be distinct for odd and even parity pair number n. Rainbow positions of parity changing transitions (n is odd) occur at larger scattering angles than those of parity conserving transitions (n is even). Parity conserving transitions exhibit—from a classical point of view—a larger effective eccentricity of the shell. No rainbow doubling due to collisions onto either the N-end or the O-end was observed. From a classical point of view the presence of a double rainbow is expected. Rotational excitation of the D2 molecules has not been observed.
Molecular dynamics of haloalkane corral formation and surface halogenation at Si(111)-7×7
Authors: Dobrin S. , Harikumar K. R. , Jones R. V. , McNab I. R. , Polanyi J. C. , Waqar Z. , Yang J. (S. Y.)
Published: October 2006

Long-chain organic molecules, 1-halododecane, RX (X=Cl,Br), adsorbed on Si(111)-7×7 were shown to form stable dimeric corrals; type I around corner holes and type II around corner adatoms S. Dobrin et al. [Surf. Sci. Lett. 600, L43 (2006)]. Here we examine the molecular dynamics of corral formation, in which mobile physisorbed adsorbates spontaneously convert to immobile. At high coverage the mechanism gives evidence of involving collisions between mobile vertical monomers, giving types I and II immobile horizontal dimers, vD+vD→h2 (I, II). At low coverage mobile vertical monomers collide with immobile horizontal ones to form largely type-II corrals, vD+h→h2 (II). Thermal reaction of corrals with X=Br brominates the surface by two distinct molecular pathways, thought to have more general applicability: “daughter-mediated” reaction of vertical vA with a low activation energy (here Ea∼5kcalmol−1) and “parent-mediated” reaction of horizontal h or h2 with high activation energy (here Ea=29kcalmol−1).
Defect control for low leakage current in K0.5Na0.5NbO3 single crystals
Authors: Kizaki Yoichi , Noguchi Yuji , Miyayama Masaru
Published: October 2006

Leakage current properties of K0.5Na0.5NbO3 (KNN) single crystals grown by a flux method have been investigated to establish a guiding principle of defect control for high-performance lead-free piezoelectric devices. The substitution of Mn at the Nb site and the following annealing under moderate oxidation condition was effective for suppressing leakage current of KNN crystals. Electron spin resonance measurements demonstrate that oxidation of Mn during annealing plays an essential role in low leakage current in the KNN system. Mn-doped KNN crystals exhibited a low leakage current density (∼10−8A∕cm2) and relatively large remanent polarization of 40μC∕cm2 at 25°C.
Doping dependence of the carrier lifetime crossover point upon dissociation of iron-boron pairs in crystalline silicon
Authors: Macdonald D. , Roth T. , Deenapanray P. N. K. , Trupke T. , Bardos R. A.
Published: October 2006

The excess carrier density at which the carrier lifetime in crystalline silicon remains unchanged after dissociating iron-boron pairs, known as the crossover point, is reported as a function of the boron dopant concentration. Modeling this doping dependence with the Shockley-Read-Hall model does not require knowledge of the iron concentration and suggests a possible refinement of reported values of the capture cross sections for electrons and holes of the acceptor level of iron-boron pairs. In addition, photoluminescence-based measurements were found to offer some distinct advantages over traditional photoconductance-based techniques in determining recombination parameters from low-injection carrier lifetimes.
Mechanisms for current-induced conductivity changes in a conducting polymer
Authors: Xu Xin , Register Richard A. , Forrest Stephen R.
Published: October 2006

A layer of polyethylene dioxythiophene:polystyrene sulfonic acid (PEDT:PSS) spun onto the surface of an inorganic semiconductor forms a highly asymmetric rectifying junction when a small current is applied and can be permanently open circuited with application of a high current density. This allows the polymer/semiconductor junction to function as a write-once-read-many-times memory element. We use x-ray photoelectron spectroscopy and temperature induced conductivity measurements to study the morphological and chemical changes responsible for the large current-induced conductivity changes. It is found that by applying a large current to the organic-inorganic semiconductor rectifying heterojunction structure Au∕PEDT:PSS∕Si, the ratio of PEDT+ to PSS− near the interface changes due to phase segregation in the presence of both high electric field (>105V∕cm) and temperature. This leads to a decrease in film conductivity by up to six orders of magnitude from its value in the conductive state.
Mating a Siegel disk with the Julia set of a real quadratic polynomial
Authors: Ble G. , Valdez R.
Published: October 2006

In this work, we show that it is possible to construct the mating between a quadratic polynomial with a Siegel disk and a real quadratic polynomial possessing a postcritical orbit that is semi-conjugate to a rigid rotation with the same rotation number as the Siegel disk.
Atg22 Recycles Amino Acids to Link the Degradative and Recycling Functions of Autophagy
Authors: Yang Zhifen , Huang Ju , Geng Jiefei , Nair Usha , Klionsky Daniel J.
Published: October 2006

In response to stress conditions (such as nutrient limitation or accumulation of damaged organelles) and certain pathological situations, eukaryotic cells use autophagy as a survival mechanism. During nutrient stress the main purpose of autophagy is to degrade cytoplasmic materials within the lysosome/vacuole lumen and generate an internal nutrient pool that is recycled back to the cytosol. This study elucidates a molecular mechanism for linking the degradative and recycling roles of autophagy. We show that in contrast to published studies, Atg22 is not directly required for the breakdown of autophagic bodies within the lysosome/vacuole. Instead, we demonstrate that Atg22, Avt3, and Avt4 are partially redundant vacuolar effluxers, which mediate the efflux of leucine and other amino acids resulting from autophagic degradation. The release of autophagic amino acids allows the maintenance of protein synthesis and viability during nitrogen starvation. We propose a “recycling” model that includes the efflux of macromolecules from the lysosome/vacuole as the final step of autophagy.
The tYNA platform for comparative interactomics: a web tool for managing, comparing and mining multiple networks
Authors: Yip Kevin Y. , Yu Haiyuan , Kim Philip M. , Schultz Martin , Gerstein Mark
Published: October 2006

Summary: Biological processes involve complex networks of interactions between molecules. Various large-scale experiments and curation efforts have led to preliminary versions of complete cellular networks for a number of organisms. To grapple with these networks, we developed TopNet-like Yale Network Analyzer (tYNA), a Web system for managing, comparing and mining multiple networks, both directed and undirected. tYNA efficiently implements methods that have proven useful in network analysis, including identifying defective cliques, finding small network motifs (such as feed-forward loops), calculating global statistics (such as the clustering coefficient and eccentricity), and identifying hubs and bottlenecks. It also allows one to manage a large number of private and public networks using a flexible tagging system, to filter them based on a variety of criteria, and to visualize them through an interactive graphical interface. A number of commonly used biological datasets have been pre-loaded into tYNA, standardized and grouped into different categories.

Availability: The tYNA system can be accessed at . The source code, JavaDoc API and WSDL can also be downloaded from the website. tYNA can also be accessed from the Cytoscape software using a plugin.

Contact:  mark.gerstein@yale.edu

Supplementary information: Additional figures and tables can be found at
CREMOFAC—a database of chromatin remodeling factors
Authors: Shipra Agrawal , Chetan Kumar , Rao M. R. S.
Published: October 2006

Motivation: Chromatin-remodeling is an important event in the eukaryotic nucleus rendering nucleosomal DNA accessible for various transaction processes. Remodeling Factors facilitate the dynamic nature of chromatin through participation of the collective action of (i) ATP and (ii) Non-ATP dependent factors. Considering the importance of these factors in eukaryotes, we have developed, CREMOFAC, a dedicated and frequently updated web-database for chromatin-remodeling factors.

Results: The database harbors factors from 49 different organisms reported in literature and facilitates a comprehensive search for them. In addition, it also provides in-depth information for the factors reported in the three widely studied mammals namely, human, mouse and rat. Further, information on literature, pathways and phylogenetic relationships has also been covered. The development of CREMOFAC as a central repository for chromatin-remodeling factors and the absence of such a pre-existing database heighten its utility thus making its presence indispensable.

Availability:  

Contact:  mrsrao@jncasr.ac.in
Fluorescence digital photography of acne using a light‐emitting diode illuminator
Authors: Ahn Hyo Hyun , Kim Soo Nam , Kye Young Chul
Published: October 2006

Background/purpose: The fluorescence findings of several dermatological diseases, such as erythrasma, tinea versicolor, and acne are helpful for diagnosis and follow‐up. However, many experience difficulty taking photographic images of fluorescence. The aim of this study was to develop a 405 nm light‐emitting diode (LED) system for fluorescence digital photography of acne and to determine whether such a diode can be used to evaluate acne.

Methods: Eight healthy acne patients were compared with controls by fluorescence digital photography using a digital camera equipped with a 405 nm LED illuminator. Digital photographs were taken by two different ways of exposure, i.e. appropriate exposure level and longer exposure. One side of the nose, cheek, and glabella was compared. The numbers and extents of fluorescence dots were counted and measured. As normal controls, seven individuals with apparent oiliness and no acne were enrolled.

Results: Red fluorescent facial dots were observed and photographed digitally using the 405 nm LED illuminator. These were more numerous and extensive on the glabella and cheeks of acne patients.

Conclusion: Fluorescence digital photography of acne was successfully performed using a 405 nm LED illuminator. This illuminator could be used for acne evaluations.
Hepatocellular oncofetal protein, glypican 3 is a sensitive marker for α‐fetoprotein‐producing gastric carcinoma
Authors: Hishinuma M , Ohashi K‐I , Yamauchi N , Kashima T , Uozaki H , Ota S , Kodama T , Aburatani H , Fukayama M
Published: October 2006

Aims Glypican 3 (GPC3) is a cell surface heparan sulphate proteoglycan expressed specifically in the fetal liver and malignant neoplasms of hepatocyte lineage. The aim was to evaluate the significance of GPC3 in α‐fetoprotein (AFP)‐producing gastric carcinoma (GC) and other forms of GC.

Methods and results We immunohistochemically evaluated GPC3 expression in representative cases of AFP‐producing GC and in a tissue microarray of a consecutive series of GCs with other markers of hepatocyte lineage (AFP, PIVKA‐II and hepatocyte antigen, HEP). In a series of 10 cases of AFP‐producing GC, we observed immunohistochemical positivity for GPC3, PIVKA‐II and HEP in 10, three and three cases in components with a hepatoid pattern and in nine, two and five cases in components with a non‐hepatoid pattern, respectively. In a series of 118 cases of GC, we observed positivity for AFP, GPC3, PIVKA‐II and HEP in one (0.8%), four (3.4%), six (5.1%) and 26 cases (22%), respectively. GPC3 was observed concurrently with AFP and discordantly with PIVKA‐II and HEP. GPC3 positivity was clearly stronger in a larger area compared with immunoreactivity for AFP.

Conclusions GPC3 is a sensitive marker for AFP‐producing GC and its hepatoid component and is therefore useful to identify this aggressive subgroup of GC.
Collaborative Improvement – Interplay but not a Game
Authors: Kaltoft Rasmus , Boer Harry , Chapman Ross , Gertsen Frank , Nielsen Jacob S.
Published: October 2006

Collaboration literally means working together. Collaborative improvement is an extension of continuous improvement and can be defined as a purposeful inter‐company interactive process that focuses on continuous incremental innovation aimed at enhancing the collaboration’s overall performance. Developing collaborative improvement is a protracted and difficult process. Previous research has identified a number of factors affecting that process and suggested that it is not so much the individual factors, but rather their interplay that determines the successful development of collaborative improvement. This article reports research aimed at developing a deeper understanding of that interplay. Ten relationships between ten factors are presented and discussed. It appears that vision, approach, trust and commercial reality are the strongest factors. These factors are, however, influenced by, or affect the other factors, notably national culture, partner characteristics and competences, the use of power, individual behaviour and commitment. The way this interplay develops varies from case to case and has great influence on the development of collaborative improvement.
SYNTHESIS OF GANGLIOSIDES DURING DEVELOPMENT AND ITS RELATION TO THE QUANTITATIVE CHANGES OF SUBCELLULAR PARTICLES OF RAT BRAIN
Authors: Rubiolo De Maccioni Alicia H. , Caputto R.
Published: October 2006

Abstract— Different subcellular fractions prepared from developing rat cerebrum were quantified by determinations of dried weights and protein contents. It was found that there is an increase of 2–2·5 times in the weights of synaptosomes and mitochondria/g of tissue during the first 20 days of extrauterine life.

A period of fast synthesis of gangliosides, with a similar pattern of increase for the different subcellular particles, was found during the first 15 days of life by study of the incorporation of injected d‐[1‐14C]glucosamine in rats at different stages of development. Attempts to find out if gangliosides from a certain fraction are precursors of those of other fractions indicated that in all fractions the gangliosides increase independently of the other fractions. It is concluded that the enzymic systems of synthesis of these glycolipids are present in vivo in all the fractions considered.
SYNAPTOSOMAL PROTEIN SYNTHESIS IN A CELL‐FREE SYSTEM*
Authors: Morgan I. G. , Austin L.
Published: October 2006

—Synaptosomes were isolated from cerebral cortex of young rats and incubated with14C‐labelledl‐leucinein vitro. Amino acid incorporation into proteins of the synaptosomal cytoplasm, mitochondria and membrane components was observed. There was no incorporation into proteins of the vesicles. The protein‐synthesizing system was not stimulated by the addition of either ATP or an ATP‐generating system. ATP at all concentrations was inhibitory.

Two different protein‐synthesizing systems operate in the synaptosome. One, sensitive to inhibition by chloramphenicol and related antibiotics, is found in the mitochondrial subfraction and the other, inhibited by cycloheximide, is located either in the membrane components or the synaptosomal cytoplasm. This second system resembles the eukaryotic ribosomal system in its sensitivity to cycloheximide. Both the synaptosomal soluble fraction and the synaptosomal membrane fractions were shown previously to contain RNA. This RNA could function in protein‐synthesizing mechanisms in the synaptosome. These results deomonstrate that protein is synthesized in axonal components and show that it is unnecessary to postulate that all axonal protein is supplied by somato‐axonal flow.
THE EFFECT OF β,β′‐IMINODIPROPIONITRILE AND ANAESTHESIA ON SOME ADENINE NUCLEOTIDES OF RAT BRAIN AND RETINA
Authors: Williams S. , Paterson R. A. , Heath H.
Published: October 2006

—A significant increase in the retinal ATP content of anaesthetised rats was found 6 days after administration of β, β′‐iminodipropionitrile (IDPN). With the development of retinal dystrophy variable ATP levels were observed from the 8th to the 12th day and low values were recorded on the 17th and 21st days.

At 8 days after IDPN administration the ATP content of anaesthetised rat brain was significantly increased with slight decreases in ADP and AMP levels.

The differences in the level of these adenine nucleotides in unanaesthetised and anaesthetised rat brain were not significant before or after IDPN administration.

These results were related to previous experiments on the action of IDPN on the electroretinal response and the later development of a retinal microangiopathy. It was suggested that IDPN has a primary neurotoxic effect followed by the development of vascular morphological changes.
ACETYL‐ AND PSEUDOCHOLINESTERASE ACTIVITIES IN SYMPATHETIC GANGLIA OF RATS1
Authors: Klingman Gerda I. , Klingman J. D. , Poliszczuk Anna
Published: October 2006

—The quantitative method of Ellman, Courtney, Andres and Featherstone (1961) was adapted to a differential assay for the determination of acetyl‐ and pseudocholinesterase activities of sympathetic ganglia of rats. The activities of the cholinesterases of superior cervical, stellate and thoracic chain ganglia and of the abdominal ganglionic complexes in apposition to the superior mesenteric and coeliac arteries (superior mesenteric, coeliac and cardiac ganglia) were measured. B.W.284C51 dibromide, 5 × 10−5m, and ethopropazine hydrochloride, 3·15 × 10−5m, were employed to inhibit selectively acetyl‐ and pseudocholinesterases, respectively. Linearity was shown to be maintained with enzyme concentrations corresponding to 0·12‐0·5 mg of ganglion (wet wt.)/incubation. Under the experimental conditions of this assay, the rates of the reaction of ganglionic acetyl‐ and pseudocholinesterases were linear for time periods greater than those employed for calculating the rates of hydrolysis in the homogenates of sympathetic ganglia. Several experimental approaches were used to ascertain the specificity of the inhibitors and of the reaction.

Of the total cholinesterase activity of sympathetic ganglia of rats, 55‐63 per cent was due to acetylcholinesterase and 31‐39 per cent to pseudocholinesterase. On the basis of the specific enzyme activity, superior cervical, stellate and superior mesenteric ganglia contained higher acetyl‐ and pseudocholinesterase activities than did thoracic chain, coeliac and cardiac (abdominal) ganglia. The specific activity of acetylcholinesterase was similar in rat and cat superior cervical ganglia and sympathetic cervical trunks while the pseudocholinesterase activity of these two tissues was somewhat lower in cats than in rats.
CELL‐FREE PROTEIN SYNTHESIS BY MOUSE BRAIN DURING EARLY DEVELOPMENT
Authors: Johnson T. C.
Published: October 2006

—Cell‐free homogenates were employed to study the nature of the mechanism that is responsible for the rapid decrement in protein synthesis during early neural development. There was a progressive loss of polypeptide synthesis in post‐mitochondrial fractions that were isolated from increasingly older tissue. By the time the animals were approximately 17 days old, the rate of amino acid incorporation had decreased to the rate that was measured in adult brain preparations. This decrement in synthetic activity was similar to that previously measured in developing intact brain cells. The loss in protein synthesis was demonstrated to be independent of cellular membrane permeability and under the influence of intracellular control mechanisms. Although the nature of the control mechanism is still not clear, a lack of template RNA to direct protein synthesis was not the limiting factor in the decreased synthesis of the older brain preparations.
METABOLIC PARAMETERS OF ONTOGENESIS OF ELECTRICAL ACTIVITY IN THE BRAIN. SODIUM‐POTASSIUM ACTIVATED ADENOSINE TRIPHOSPHATASE IN DEVELOPING CHICK EMBRYO BRAIN
Authors: Zaheer N. , Iqbal Z. , Talwar G. P.
Published: October 2006

—(1) The activity of the Na‐K ATPase in the particulate fraction of the chick embryo brain has been assayed at different stages of development with the objective of finding whether or not changes in the activity of this enzyme bear any relation to the maturation of spontaneous and evoked electrical activity of the growing chick brain.

(2) The specific activity of the enzyme is low on day 6 and it rises rapidly between days 10 and 12, at which time it attains a plateau and remains essentially unchanged from day 12 until day 20. Experimental evidence rules out the possible presence of an inhibitor of the enzyme in 8‐day‐old brain homogenates, suggesting that these developmental changes in the activity of the enzyme may represent new synthesis of enzyme rather than its activation. The period between days 10 and 12 does not represent a unique stage of general protein synthesis.

(3) The chick brain particulate enzyme has an optimum activity at pH 7·4 and at 37°. It is optimally activated by a Na+ concentration of 100mm and K+ concentration of 20 mm. The enzyme is inhibited by ouabain and Ca2+.

(4) The results have been discussed.
EFFLUX OF ACCUMULATED CALCIUM FROM BRAIN MICROSOMES1
Authors: Robinson J. D.
Published: October 2006

—(1) A microsomal preparation from rat brain accumulated calcium by an ATP‐dependent process during incubation in a hypotonie medium. Accumulation was reduced in media containing 100 mm‐NaCl, 100 mm‐KCl or 100 mm‐choline chloride or 200 mm‐sucrose. During prolonged incubations NaCl further decreased calcium content unlike the other ions; this suggests a release of accumulated calcium by NaCl.

(2) Microsomes that had accumulated calcium during a prior incubation (‘preloaded microsomes’) lost calcium during a subsequent incubation. NaCl specifically increased the rate of loss of calcium. Ouabain had no effect on the NaCl‐induced efflux.

(3) Loss of calcium from preloaded microsomes, both with and without NaCl, had a high temperature coefficient. Measurements of monovalent cation content showed no correlation of either the uptake or loss with a simple ion‐exchange process and the accumulated calcium did not exchange with calcium in the medium.

(4) ATP specifically reduced the efflux of calcium from preloaded microsomes. Although the diminished loss of calcium could be attributed in part to reaccumulation, this was not the only mechanism since ATP also reduced the loss from continuously perfused microsomes preloaded with calcium.

(5) A series of neurotropic drugs had little effect on the efflux of calcium. Low concentrations of chlorpromazine decreased calcium retention less than 20 per cent.
LIPIDS AND PROTEOLIPIDS IN ISOLATED SUBCELLULAR MEMBRANES OF RAT BRAIN CORTEX*
Authors: Lapetina E. G. , Soto E. F. , Robertis E. De
Published: October 2006

Abstract—

The cerebral cortex of the rat was submitted to an extensive cell fractionation schedule and in the various fractions, protein, proteolipid protein, total phospholipids, cholesterol, galactolipids, plasmalogens, and gangliosides were determined. With increasing purification the different isolated membranous structures: i.e. myelin, nerve ending membranes, synaptic vesicles, mitochondria, and microsomes, show a definite biochemical specialization reflected in their lipid composition. The presence of gangliosides in some nerve ending membranes is confirmed, and the possible functional role of these acid glyco‐lipids is discussed.

The importance of proteolipids as structural components of membranes is recognized. The richness of these compounds in myelin is confirmed and a special localization in the nerve ending membranes is indicated.

Analysis of the molar ratios of the different lipids and proteins in the isolated membranes demonstrates that each one has a specific pattern of molecular organization. This pattern is discussed in relation to the macromolecular structures revealed by electronmicroscopy and some of the molecular models postulated for cell membranes.
ACETYLCHOLINESTERASE IN THE FELINE CEREBELLUM
Authors: Phillis J. W.
Published: October 2006

Abstract—

Histochemical procedures for the localisation of AChE have been used on the cerebella of normal and operated cats to investigate the presence of cholinergic pathways. The evidence indicates that some mossy afferent fibres and deep nuclear cells are cholinergic. The presence of AChE in many cells in the granule cell layer suggests that some parallel fibres and association pathways in the cerebellum may also be cholinergic. The relationship of these results to studies on the pharmacology and distribution of choline acetyltransferase in the cerebellum is discussed.
AN AUTORADIOGRAPHIC STUDY OF THE FLOW OF PROTEIN AND RNA ALONG PERIPHERAL NERVE
Authors: Peterson J. A. , Bray J. J. , Austin L.
Published: October 2006

Abstract— Bath chicken spinal cord and the posterior chamber of the rat eye have been injected with either [3H]leucine or [3H]orotic acid. The movement of newly synthesized protein and RNA down the sciatic and optic nerves was followed by means of autoradiography. Protein moved down both nerves by axoplasmic flow, the protein being confined to intra‐axonal spaces. RNA appeared to move at about the same rate as protein, but much of the newly formed RNA appeared in structures outside the axons, particularly in Schwann and glial cells. There was, however a considerable proportion of the RNA inside the axons. This RNA may be involved in the direction of protein synthesis at sites along the axonal processes.
THE CATIONIC COMPOSITION OF INCUBATED CEREBRAL CORTEX SLICES
Authors: Franck G. , Cornette M. , Schoffeniels E.
Published: October 2006

Abstract— 1. A new type of cutting table is described. It makes use of the elastic properties of a nylon thread, 0·08 mm thick, in which longitudinal vibrations greatly increase its ability to cut through soft tissue. Two slices of cerebral cortex may thus be obtained within 3–4 min after the death of an animal.

2. The extent of the swelling of a brain slice, as well as the ionic shift, is directly related to the amount of oxygen in the incubating fluid. Under the best conditions of oxygen supply, the swelling of a first slice was close to 12·2 ± 4·3 per cent after 5 hr of incubation. The corresponding values for the Na+ and K+ contents were respectively 119·3 ± 6·9 and 70·9 ± 5·0 μequiv./g of final fresh weight (P2).

3. Incubation in complete anoxia leads to a considerable shift in the cation content of the slice, which acquires a composition close to that of the incubating fluid. This suggests that a large part of the cell population is still metabolically active when oxygen is present.

4. The inulin space represents 47·1 ± 5·8 per cent of the initial fresh weight. It is independent of the amount of fluid taken up by the slice as well as of anoxia.

5. The cation content of the non‐inulin space, calculated by assuming that the inulin space has the same composition as the incubation medium, was 77·7 μequiv./ml and 160·3 μequiv./ml for Na+ and K+ respectively.

6. The meaning of the inulin space, as well as the physico‐chemical state of the cations in the slice, are discussed.
PASSAGE OF 5‐HYDROXYTRYPTAMINE THROUGH THE BLOOD‐BRAIN BARRIER, ITS METABOLISM IN THE BRAIN AND ELIMINATION OF 5‐HYDROXYINDO‐LEACETIC ACID FROM THE BRAIN TISSUE
Authors: Bulat M. , Supek Z.
Published: October 2006

Abstract— 5‐HT was injected intravenously in rats (10 mg/kg) and a marked increase in brain 5‐HT and 5‐HIAA was observed. For the first 10 min after injection the penetration of 5‐HT into the brain and formation of 5‐HIAA is evident. After 10 min degradation of exogenous 5‐HT and elimination of 5‐HIAA are prominent. Metabolism of exogenous 5‐HT in the brain is very fast (half‐life between 5 and 10 min; completely metabolized in approximately 80 min). The importance of these results in explaining the permeability of blood‐brain barrier to 5‐HT is discussed.

Experiments on brain slices show that 5‐HT is more readily metabolized in brain tissue than eliminated into incubation medium. In contrast, 5‐HIAA very easily leaves brain tissue.
CHOLINESTERASES OF RAT SYMPATHETIC GANGLIA AFTER IMMUNOSYMPATHECTOMY, DECENTRALIZATION AND AXOTOMY12
Authors: Klingman Gerda I. , Klingman J. D.
Published: October 2006

Abstract— Immunosympathectomy was produced in Sprague‐Dawley rats by the subcutaneous injection of 300 units of nerve growth factor (NGF)‐antiserum (1.56 mg of freeze‐dried serum)/g/day for 6 days, the first dose being given 5–8 hr after birth. The immunosympathectomized rats and their control littermates were killed 2½ and 7 months after birth.

Ganglionic acetylcholinesterase and pseudocholinesterase activities were measured by an adaption (Kungman, Kungman and Pouszczuk, 1968) of the colorimetric method of Ellman, Courtney, Andres and Featherstone (1961). Following immunosympathectomy the activities of these enzymes decreased significantly in superior cervical, stellate, thoracic chain, cardiac (abdominal), coeliac and superior mesenteric ganglia. The reduction of the acetylcholinesterase activity was greater than expected in a number of sympathetic ganglia, e.g. superior cervical, stellate, coeliac and cardiac ganglia, if one considered that only the postganglionic neurons were affected by immunosympathectomy. The activities of these enzymes were also reduced in the cervical sympathetic trunks from NGF‐antiserum‐treated rats. By means of decentralization and axotomy it was shown that 45 per cent of the total ganglionic acetylcholinesterase activity was associated with the preganglionic and 55 per cent with the postganglionic elements of the superior cervical ganglion from control rats. It was concluded that immunosympathectomy also affects the preganglionic sympathetic neurons. It is not known whether this is a primary effect of the NGF‐antiserum or a secondary effect resulting from the absence of over 90 per cent of the postganglionic sympathetic cell bodies.
RESPIRATION IN VITRO OF SYNAPTOSOMES FROM MAMMALIAN CEREBRAL CORTEX
Authors: Bradford H. F.
Published: October 2006

Abstract— —(1) The respiratory properties of synaptosomes and mitochondria from mammalian cerebral cortex are compared.

(2) Synaptosome showed high and linear respiration with glucose and pyruvate as substrates in Krebs‐Ringer media. Mitochondria showed such respiration only with pyruvate as substrate in media lacking Na and high in K and phosphate.

(3) Exposure of synaptosomes to hypotonic media caused loss of lactate dehydrogenase (LDH) and protein, and respiration diminished and became non‐linear.

(4) Both ATP and phosphocreatine were synthesised by synaptosomes with glucose as substrate. ATP was synthesised by mitochondria in the presence of pyruvate.

(5) Synaptosome but not mitochondria showed some capacity for active accumulation of potassium.

(6) Both mitochondria and synaptosomes respired with glutamate as substrate. Glutamate caused 80 per cent loss of ATP and phosphocreatine in synaptosomes but did not diminish the level of mitochondrial ATP.
CHARACTERIZATION OF RAT BRAIN RIBONUCLEIC ACIDS BY AGAR GEL ELECTROPHORESIS
Authors: Tencheva Z. S. , Hadjiolov A. A.
Published: October 2006

Abstract— —The characteristics of total and rapidly‐labelled RNAs of rat brain were studied by agar gel electrophoresis. The bulk (more than 90 per cent) of total, nuclear and cytoplasmic brain RNA was represented by the 28 S, 18 S and 4 S RNA components. The 28 S/18 S RNA mass ratio in cytoplasmic RNA was 2·55. Lower values for this ratio were obtained with total and nuclear RNAs. Five minor RNA components were detected in total brain RNA with mobilities in agar gel corresponding to 24 S, 22 S, 14 S, 9 S and 6 S. Two broad rapidly labelled RNA components were detected in total and nuclear (but not in cytoplasmic) brain RNA with mobilities corresponding to about 45 S and 31 S. These fractions were of nuclear origin and resembled ribosomal precursor RNAs of other animal tissues. In cytoplasmic RNA the radioactivity and ultraviolet profiles coincided at all labelling times down to 1 hr. The G + C/A + U ratio of brain RNA was 1·50 for total RNA, 1·39 for nuclear RNA and 1·59 for cytoplasmic RNA. The G + C/A + U ratio of 1 hr‐labelled total brain RNA (determined by 32P‐distribution) was 0·94. This ratio rose to 1·31 at 24 hr labelling. The possible significance of these results for the elucidation of ribosomal and messenger RNA metabolism in brain is discussed.
INHIBITION BY γ‐HEXACHLOROCYCLOHEXANE OF ACETYLCHOLINE‐STIMULATED PHOSPHATIDYLINOSITOL SYNTHESIS IN CEREBRAL CORTEX SLICES AND OF PHOSPHATIDIC ACID‐INOSITOL TRANSFERASE IN CEREBRAL CORTEX PARTICULATE FRACTIONS1
Authors: Hokin Mabel R. , Brown Donna F.
Published: October 2006

Abstract—

γ‐Hexachlorocyclohexane inhibits the ACh‐stimulated synthesis of phosphatidylinositol in guinea pig cerebral cortex slices, as measured either by the incorporation of [2‐3H]inositol or of 32P. Phosphatidylinositol synthesis in the control slices is not inhibited.

The synthesis of phosphatidylinositol from CDP‐diglyceride in cerebral cortex microsomal preparations is inhibited by γ‐hexachlorocyclohexane. The incorporation of [2‐3H]inositol into lipid in the absence of added cytidine nucleotide in these preparations is not inhibited.

δ‐Hexachlorocyclohexane profoundly inhibits phosphatide synthesis and phosphate metabolism in cerebral cortex slices both in the presence and absence of ACh. This isomer also inhibits the exchange reaction for the incorporation of [2‐3H]inositol into lipid in the microsomal preparations.

α‐, and β‐Hexachlorocyclohexanes do not inhibit either ACh‐stimulated or control synthesis of phosphatidylinositol in cerebral cortex slices; nor do they inhibit the exchange reaction for [2‐3H]inositol incorporation into lipid in the microsomal preparations.

The specific effects of γ‐hexachlorocyclohexane are taken as providing evidence that ACh‐stimulated phosphatidylinositol synthesis in cerebral cortex slices probably involves the CDP‐diglyceride pathway. The possibility is discussed that the primary action of ACh in this system is to cause an increased activity of diglyceride kinase to provide phosphatidic acid for this pathway.
LACK OF ABNORMALITY IN BRAIN AROMATIC AMINES IN RATS AND MICE SUSCEPTIBLE TO AUDIOGENIC SEIZURE*
Authors: McGeer E. G. , Ikeda H. , Asakura T. , Wada J. A.
Published: October 2006

Abstract—

The levels of certain amines (catecholamines, 5‐HT, and ‘histamine’) and of certain enzymes (tyrosine hydroxylase, tryptophan hydroxylase, ChAc, or AChE) in whole brain or selected brain areas of rats and mice susceptible to audiogenic seizure have been compared with the levels in matched groups of non‐sensitive animals. Sensitive groups included both those where susceptibility is inborn and those where it is induced by administration of methionine sulphoximine or thiosemicarbazide. No significant difference was found which could be correlated with susceptibility to audiogenic seizure.
KINETICS OF THE BIOSYNTHESIS OF PHOSPHOLIPIDS IN NEURONS AND GLIAL CELLS ISOLATED FROM RAT BRAIN CORTEX
Authors: Freysz L. , Bieth R. , Mandel P.
Published: October 2006

—32P incorporation into different rat‐brain cortex neuronal and glial phospholipids was investigated. The half life of each compound was measured.

Neuronal phospholipids had a faster turnover than glial phospholipids. Phosphatidyl‐inositol and choline plasmalogen had the fastest, diphosphatidylglycerol the lowest turnover in both cell‐types. Phosphatidylcholine, ethanolamine phospholipids and serine phospholipids had turnover intermediate with that of the previously described compounds.

Turnover of neuronal sphingomyelin was similar to that of phosphatidylcholine, whereas in glial cells it was much lower.
RELATIONSHIPS BETWEEN ENERGY RESERVES AND FUNCTION IN RAT SUPERIOR CERVICAL GANGLION1
Authors: Härkönen Matti H. A. , Passonneau Janet V. , Lowry O. H.
Published: October 2006

—Major components of the energy reserves of the isolated superior cervical ganglion (ATP, phosphocreatine, glucose, glycogen and lactate) were measured under aerobic and anaerobic conditions. Complete anaerobiosis was maintained by incubation in mineral oil through which N2 had been bubbled. From the initial rate of change in the energy reserves, a metabolic rate was calculated which would be equivalent to the consumption of 93 m‐moles of O2 per kg per hour. Under aerobic conditions (oxygenated moist chamber) a similar metabolic rate was calculated. In contrast to the anaerobic state, initial energy expenditure was almost exclusively at the expense of glucose. Continuous supramaximal stimulation in O2 increased energy expenditure by a factor of three; both glucose and glycogen were utilized from the outset, and lactate accumulated in the initial periods.

Ganglionic transmission failed in both resting and stimulated states in spite of the continued presence of very substantial levels of ATP and phosphocreatine. Failure seemed to be associated not with ATP depletion but rather with the complete disappearance of glucose and glycogen.
A MODIFIED PROCEDURE FOR THE ANALYSIS OF MIXTURES OF TISSUE GANGLIOSIDES1
Authors: MacMillan V. H. , Wherrett J. R.
Published: October 2006

Abstract— A modified procedure is described for quantification of gangliosides in a mixture using thin‐layer chromatography. Using this procedure, the gangliosides in human peripheral nerve were quantified, and compared with those in cerebral cortex and white matter.