bluuebunny/crossref_metadata_2025_split huggingface dataset:
6,7‐Dichloroquinoxaline‐2,3‐Dione is a Competitive Antagonist Specific to Strychnine‐Insensitive [3H]Glycine Binding Sites on the N‐Methyl‐D‐Aspartate Receptor Complex
Authors: Ogita Kiyokazu , Yoneda Yukio 
Published: October 2006

Abstract:Multiple binding sites on the N‐methyl‐D‐aspartate (NMDA) receptor complex were examined using rat brain synaptic membranes treated with Triton X‐100. Binding of [3H](+)‐5‐methyl‐10,11‐dihydro‐5H‐dibenzo[a,dcyclohepte5,10‐imine ([3H]MK‐801), a noncompetitive NMDA antagonist, in the presence of 10 μM L‐glutamate not only was inhibited by different types of antagonists, such as 6,7‐dichloro‐3‐hydroxy‐2‐quinoxaline‐carboxylate, 7‐chlorokynurenate, and 6,7‐dichloroquinoxaline‐2,3‐dione (DCQX), but also was abolished by non‐NMDA antagonists, including 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione and 6,7‐dinitroquinoxaline‐2,3‐dione. The inhibition of [3H]MK‐801 binding by these compounds was invariably reversed or attenuated by addition of 10 μM glycine. Among these novel antagonists with an inhibitory potency on [3H]MK‐801 binding, only DCQX abolished [3H]glycine binding without inhibiting [3H]glutamate and [3H](±)‐3‐(2‐carboxypiperazin‐4‐yl)propyl‐1‐phosphonate bindings. Other antagonists examined were all effective as displacers of the latter two bindings. These results suggest that DCQX is an antagonist highly selective to the strychnine‐insensitive glycine binding sites with a relatively high affinity.
Production and Characterization of Monoclonal Antibodies to the Major Peripheral Myelin Glycoprotein P0
Authors: Bollensen Edgar , Scheidt Peter , Schachner Melitta 
Published: October 2006

Abstract:Several monoclonal antibodies were generated against the major glycoprotein P0 of human peripheral nervous system myelin. Antibodies were selected for their reactivity with P0 in Western blots. The antibodies were of the immunoglobulin G subclass and reacted with the glycopeptidase F‐treated P0, indicating that the reactive epitope resides in the protein backbone. In fresh frozen and paraffin‐embedded sections of central and peripheral nervous system of rat and human, P0 antibody 592 reacted with myelin sheaths of peripheral, but not central, nervous system.
Comparison of Transmitter Amino Acid Levels in Rat Globus Pallidus and Neostriatum During Hypoglycemia or After Treatment with Methionine Sulfoximine or γ‐Vinyl γ‐Aminobutyric Acid
Authors: Fonnum F. , Paulsen R. E. 
Published: October 2006

Abstract:The levels of amino acids in globus pallidus, a structure heavily innervated with γ‐aminobutyric acid (GABA)‐ergic terminals but few glutamergic terminals, were compared with the levels in neostriatum, a structure richly innervated with glutamergic terminals but intermediate in GABAergic terminals. The level of glutamate in neostriatum was twice as high as in globus pallidus whereas the level of GABA in globus pallidus was three times higher than in neostriatum. The level of aspartate was similar in both regions whereas the level of glutamine was correlated with the level of glutamate. Methionine sulfoximine, a glutamine synthetase inhibitor, reduced the level of glutamine to 10‐20% of control in both structures. This reduction was accompanied by the largest decrease in the level of glutamate in neostriatum, indicating that transmitter glutamate turns over more rapidly than other glutamate pools. Likewise, insulin decreased the levels of glutamate and glutamine more in neostriatum than in globus pallidus. γ‐Vinyl GABA increased the level of GABA in globus pallidus more than in neostriatum although the percent increase was largest in neostriatum. Treatment with γ‐vinyl GABA was accompanied by a large reduction in the level of glutamine that was correlated with the increase in the level of GABA, indicating that a substantial proportion of the glutamine pool is linked to GABA metabolism.
Effects of 1‐Methyl‐4‐Phenyl‐ 1,2,3,6‐Tetrahydropyridine and 1 ‐Methyl‐4‐Phenylpyridinium Ion on ATP Levels of Mouse Brain Synaptosomes
Authors: Scotcher Kevin P. , Irwin Ian , DeLanney Louis E. , Langston J. William , Di Monte Donato 
Published: October 2006

Abstract:Mouse brain synaptosomes, essentially devoid of mitochondrial contamination, were used as a model to study the effects of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) and its toxic metabolite 1‐methyl‐4‐phenylpyridinium ion (MPP+) on the levels of ATP of neuronal terminals. Similar to known inhibitors of ATP synthesis, both MPTP and MPP+ caused a dramatic depletion of synaptosomal ATP. This depletion was dose dependent and occurred as a relatively early biochemical event in the absence of any apparent damage to synaptosomal membranes. MPP+ was more effective than its parent compound in decreasing ATP; it induced a significant loss at concentrations (10–100 γM) similar to those it reaches in the brain in vivo. MPTP‐induced ATP depletion was completely prevented by the monoamine oxidase B inhibitor deprenyl, which, on the contrary, was ineffective against MPP+. As expected in view of the heterogeneous population of nerve terminals present in our synaptosomal preparations, the catecholamine uptake blocker mazindol did not significantly affect the ATP loss caused by both compounds. Data indicate that (1) administration of MPTP may cause a depletion of ATP within neuronal terminals resulting from the generation of MPP+, and (2) exposure to the levels of MPP+ reached in vivo may cause biochemical changes that are nonselective for dopaminergic terminals.
Roxithromycin inhibits tumor necrosis factor‐α‐induced matrix metalloproteinase‐1 expression through regulating mitogen‐activated protein kinase phosphorylation and Ets‐1 expression
Authors: Oyama T. , Matsushita K. , Sakuta T. , Tokuda M. , Tatsuyama S. , Nagaoka S. , Torii M. 
Published: October 2006

Background and Objective:  In periodontitis, matrix metalloproteinases (MMPs) are upregulated in response to locally released inflammatory cytokines, resulting in pathologic processes. Roxithromycin is a 14‐membered ring macrolide antibiotic with broad‐spectrum antibacterial effects against oral pathogens and immunomodulatory effects. Recently, we reported that roxithromycin inhibits tumor necrosis factor (TNF)‐α‐induced vascular endothelial growth factor expression in human periodontal ligament (HPDL) cell cultures. In the present study, we examined the effect of roxithromycin on TNF‐α‐induced MMP‐1 production by HPDL cells.Material and Methods:  Cultured cells were incubated with 1% fetal bovine serum for 24 h, followed by treatment with 10 ng/ml TNF‐α, 10 µm roxithromycin, and mitogen‐activated protein kinase inhibitor at various concentrations. Culture supernatants and sediments were collected at different time‐points and used for enzyme‐linked immunosorbent assays, and northern and western blot analyses.Results:  In HPDL cell cultures, roxithromycin strongly inhibited TNF‐α‐induced MMP‐1 mRNA expression and production. The inhibition of MMP‐1 gene expression by roxithromycin was dependent on de novo protein synthesis and was regulated at the transcriptional level. Roxithromycin significantly inhibited TNF‐α‐induced c‐Jun N‐terminal kinase activation (JNP) and marginally inhibited extracellular signal‐regulated kinase (ERK) 1/2 activation, but not p38 mitogen‐activated protein kinase activation. Furthermore, roxithromycin reduced the induction of Ets‐1, one of the critical factors in MMP‐1 transcription.Conclusion:  Roxithromycin inhibits TNF‐α‐mediated MMP‐1 induction through the downregulation of ERK1/2 and JNK activation and the subsequent reduction of Ets‐1, suggesting that roxithromycin may have therapeutic use in periodontitis and other chronic inflammatory conditions involving MMP‐1 induction.
What Are Mathematicians Doing?
Authors: Friedman Bernard 
Published: October 2006

Let me emphasize the point I have been trying to make. The mathematician's playing with the roots of equations, a play which had no practical motivations and almost no possibilities of practical application, led to the recognition of the importance of symmetry and groups. The study of theory of groups led to mathematical discoveries in geometry and differential equations, and finally to prediction of the existence of a new elementary particle. Surely a surprising outcome for the ivory-tower speculations of an impractical mathematician!
Despite my professional bias, I must acknowledge that the importance of symmetry was recognized before mathematicians invented the theory of groups. In 1794 William Blake wrote:
Tiger, Tiger, burning bright In the forests of the night, What immortal hand or eye Could frame thy fearful symmetry?
However, to the mathematicians must be given the credit of recognizing that, to understand symmetry, you must study the theory of groups. I can now answer my original question, What are mathematicians doing? They are trying to make precise the intuitions of poets.
Coordinated Planning for Science in Communist Europe
Authors: Jordan Lloyd F. 
Published: October 2006

The Council is not engaged in the supranational formulation of policy and planning on scientific research and technology, but has made considerable progress in coordinating research policies and plans on a limited number of scientific and technical problems of priority interest and of common concern to all members. The establishment of national science-planning institutions in CEMA countries and the adoption of a uniform approach to the formulation of national science policies and plans must be considered basic procedures for achieving international coordination of their efforts.
The creation of organizational units within CEMA to deal specifically with the coordination of science policies and plans represents a strengthening of the institutional framework that is necessary for coordination of an internationally cooperative effort in research and technology. Moreover, CEMA's 1-year plan for science and technology has probably been of considerable value as a pilot project for the formulation of the research plan for 1966-70. The delineation of a limited number of important scientific and technical problems of common interest to the members, and the allocation of research projects to a country having the highest capability to conduct them, hold considerable promise for financial savings and for improved utilization of the limited scientific manpower and research facilities of the CEMA countries. While all these measures are significant in CEMA's attempt to improve coordination of science policy and planning, only time will enable true assessment of their effectiveness. The Council's scheme for the specialization of labor in research and technology has met and will undoubtedly continue to meet, considerable opposition by various segments of the scientific communities because of deep-rooted and long-standing national prejudices, and reluctance of vested interests to give up research activities in which they are interested and to which their professional futures are tied. Moreover, opposition to CEMA-sponsored programs for specialization in research will continue to stem from the desire of some member countries further to reduce Russian influence in their domestic affairs.
While recognizing the financial savings that can accrue to them from division of labor in research within CEMA, the smaller countries cannot be unaware that there is probably a limit to which the Soviet Union, with its vast scientific and technological base, is willing to participate in the division-of-labor scheme. As a world power, the Soviet Union can hardly become dependent upon other members of CEMA in any field. Nevertheless, by promoting the coordination of research plans and a division of labor among CEMA members, the Soviet Union stands to gain by having its scientific-research effort augmented in several fields by the efforts of other members.
Graduate Student Stipends
Authors: Gruner Wayne R. 
Published: October 2006

The situation of graduate students in physics is profoundly influenced by federal support, which has been applied with mixed, and occasionally contradictory, purpose.
There are five important goals in the provision of graduate student stipends: (i) maintenance of "distinction for excellence"; (ii) rational distribution over scientific fields and subfields; (iii) constructive involvement of graduate students in undergraduate teaching; (iv) rational geographic and institutional distribution; and (v) administrative simplicity.
These goals may be approached by making several adjustments of the present system.
1) The preeminence of individual predoctoral fellowships should be restored. They should be awarded sparingly to at most five percent of the graduate student population.
2) The great majority of stipends should take the form of traineeships. They should be assigned to departments according to rational criteria.
3) Research assistantships should be continued at a reduced level. Their maintenance will protect research activities of specific public interest when necessary.

4) Teaching should be incorporated into the normal responsibilities of fellows, trainees, and research assistants. Teaching
assistance
should be regarded as a budgeting category and not as an identifying characteristic of a particular group of students.
Standardized Ability Tests and Testing
Authors: Goslin D. A. 
Published: October 2006

At the outset a distinction was made between criticisms directed at the validity of tests and criticisms not affected by the validity of the tests. It was noted further that all criticisms of tests must take into consideration the type of test and the use to which the test is put.
Criticisms of the validity of tests involved the following issues: (i) tests may be unfair to certain groups and individuals, including the extremely gifted, the culturally disadvantaged, and those who lack experience in taking tests; (ii) tests are not perfect predictors of subsequent performance; (iii) tests may be used in overly rigid ways; (iv) tests may not measure inherent qualities of individuals; and (v) tests may contribute to their own predictive validity by serving as self-fulfilling prophecies.
Criticisms that are more or less independent of test validity included the effects of tests on (i) thinking patterns of those tested frequently; (ii) school curricula; (iii) self-image, motivation, and aspirations; (iv) groups using tests as a criterion for selection or allocation, or both; and (v) privacy. Several concluding remarks are in order:

1) This paper has focused almost entirely on
criticisms
of tests. However, the positive value of standardized tests should not be ignored. Here we must keep in mind what possible alternative measures would be used if standardized tests were abandoned.

2) We must begin thinking about tests in a much broader perspective— one that includes consideration of the social effects of tests as well as their validity and reliability.
3) Finally, an effort should be made to develop rational and systematic policies on the use of tests with the culturally disadvantaged, the dissemination of test results, and the problem of invasion of privacy. Such policies can be formulated only if we are willing to take a long hard look at the role we want testing to play in the society. Standardized tests currently are a cornerstone in the edifice of stratification in American society. It is up to the social scientist to conduct research that will enable policy makers in education, business and industry, and government to determine in a consistent and rational way the ultimate shape of this edifice.
Enzymatic Modification of Transfer RNA
Authors: Söll Dieter 
Published: October 2006

The molecular events leading to the synthesis of mature tRNA are only now becoming amenable to experimental study. In bacterial and mammalian cells tRNA genes are transcribed into precursor tRNA. These molecules, when isolated, contain additional nucleotides at both ends of the mature tRNA and lack most modified nucleosides. Presumably, specific nucleases ("trimming" enzymes) cut the precursor to proper tRNA size. The C-C-A nucleotide sequence of the amino acid acceptor end common to all tRNA's does not seem to be coded by tRNA genes, and may be added to the trimmed molecules by the tRNA-CMP-AMP-pyrophosphorylase. Modifications at the polynucleotide level of the heterocyclic bases or the sugar residues give rise to the modified nucleosides in tRNA. Although newly available substrates have allowed the detection of more of the enzymes involved in these reactions, there is still no knowledge about the sequence of modification or trimming events leading to the synthesis of active tRNA. Progress in these studies may not be easy because enzyme preparations free of nucleases or other tRNA modifying enzymes are required.
The role of the modified nucleosides in the biological functions of tRNA is still unknown. Possibly pseudouridine is required for ribosome mediated protein synthesis; some other modified nucleosides in tRNA are not required for this reaction, but may enhance its rate. What might be the role of the large variety of modified nucleosides in tRNA? One is tempted to speculate that such nucleosides are important in other cellular processes in which tRNA is thought to participate such as virus infection, cell differentiation, and hormone action. Mutants in a number of tRNA-modifying enzymes are needed in order to extend our knowledge of their purpose and of tRNA involvement in other biological processes. But unless tRNA-modifying enzymes specific for a particular tRNA species exist, no simple selection procedure can be devised. Possibly some of the regulatory mutants of amino acid biosynthesis may prove to affect tRNA-modifying enzymes.
Transfer RNA's are macromolecules well suited for the study of nucleic acid-protein interactions. The tRNA molecules are structurally very similar, and they interact with a large number of enzymes or protein factors. Each aminoacyl-tRNA synthetase, for instance, very precisely recognizes a set of cognate isoacceptor tRNA's. The availability of the tRNA-modifying enzymes adds another dimension to the problem of the nature of specific recognition of tRNA by proteins. There are some tRNA-modifying enzymes, such as the uracil-tRNA methylase, which may recognize all tRNA species, while others, such as the isopentenyl-tRNA transferase, probably recognize only a selected set of tRNA molecules, even with different amino acid accepting capacities. With well-characterized RNA precursor and tRNA molecules we can hope to delineate those features of primary, secondary, and tertiary structure involved in the specific interactions of tRNA with these enzymes.
Thermochemical Hydrogen Generation
Authors: Wentorf R. H. , Hanneman R. E. 
Published: October 2006

The basic concepts for thermochemical hydrogen generation processes have been summarized in this article. A useful set of criteria has been described for the screening and selection of potentially viable, multistep, closedcycle thermochemical processes for hydrogen generation. Three illustrative, new closed-cycle processes have been discussed, indicating potential, overall thermal efficiencies ranging from approximately 40 to 60 percent. Combined thermochemical-electrolytic schemes also warrant further consideration. Principal technical problems in the development of such thermochemical closed-cycle and mixed-cycle processes are expected to include primarily materials compatibility, reaction kinetics, separation techniques, and heat-exchanger systems.
As natural gas supplies decline and prices rise, new open-cycle thermochemical processes based on water and other fossil fuel feedstocks will be the first important new technology in supplying the growing hydrogen needs of industry for at least the next two decades. Conventional electrolysis technology does not appear to be a competitor for large-scale supplies in this century unless very low off-peak electrical power rates become available, although electrolysis will be the best technique for some small-scale uses. Further analysis will be required to determine if closed-cycle thermochemical or mixed-cycle methods will displace electrolysis or other methods as the principal technology for the production of hydrogen on a large scale for the longer term.
Low Light Level Detectors for Astronomy
Authors: Boyce Peter B. 
Published: October 2006

There is an almost bewildering variety of detectors being used for ground-based astronomical observations. Many of the detectors have advantages for particular projects. One-dimensional detectors are simple, yet suitable for spectroscopy. Other detectors offer high photometric precision and dimensional stability. Some are designed for observing only faint objects and some for bright ones. Sometimes the necessity of having a high quantum efficiency at a particular wavelength dictates the choice of detector.
In reality the situation is even more chaotic. This review has not covered some of the exotic detectors that have been developed for x-ray and far-ultraviolet imaging from spacecraft. These detectors use devices such as resistive plates, multianode or crossed-wire microchannel plates, and so on. These devices have not yet seen extensive use in ground-based applications, and their future as visible light detectors remains uncertain.
The reasons for the development of such a wide variety of detectors are clear. Commercially available devices are simply not capable of meeting the low light level and photometric performance capabilities needed for astronomical observations. The driving forces are the commercial and military applications for detectors, and with few exceptions there has not been sufficient funding available to mount a detector development program for astronomy. Therefore, astronomers have sought to adapt existing commercial devices to the particular problem at hand. The large number of individual efforts summarized in this review is the result.
In the future, I expect the variety to diminish as one or two really good detectors become capable of performing well under the wide variety of observational conditions encountered in astronomy. Many people have proclaimed the ultimate detector to be just around the corner. This is yet to happen. However, I venture to speculate that low-noise, high-performance CCD detectors with a format of 500 by 500 or larger will emerge as the preferred astronomical detector within the next few years. I also expect photographic plates will continue to be used for the many applications requiring wide fields up to 10,000 pixels on a side. Finally, as the detectors approach the ultimate quantum limit, attention will shift away from them and toward development of the system necessary to manipulate, display, and extract the information from the 250,000 numbers that make up a 500 by 500 digital image.
Apparatus for the Determination of Carbon Dioxide in the Respiration of Apples
Authors: Harding P. L. , Maney T. J. , Plagge H. H. 
Published: October 2006

A respiration chamber of low original cost was used, which because of its large size was adapted to handling samples of considerable bulk or quantity. The most important feature of the chamber was its wide mouth, which permitted easy insertion and removal of samples.
With the double system of connections, either total or intermittent determinations were made with only momentary stoppage of the air-stream.
The flow-meter proved very satisfactory in maintaining a known and uniform rate of aeration.
The apparatus described was admirably adapted to the determination of carbon dioxide as a measure of respiration on apples, tomatoes and cut flowers.
A Sensitive Color Reaction for the Detection of Uracil and Cytosine
Authors: Johnson Treat B. 
Published: October 2006

(1) Uracil and cytosine are both transformed quantitatively into 5,5-dichloroxyhydrouracil by interaction with superoxol and concentrated hydrochloric acid.
(2) This 5,5-dichloroxyhydrouracil reacts with barium hydroxide immediately at ordinary temperature giving the purple colored barium salt of dialuric acid.
(3) Both uracil and cytosine can be detected successfully in minute quantities by application of the technique discussed in this paper.