bluuebunny/crossref_metadata_2025 huggingface dataset:
GRAPH‐REALIZABILITY OF MATROIDS
Authors: Inukai Thomas , Weinberg Louis
Published: December 2006

Summary

A graph‐realizability algorithm of a general matroid is presented in this paper. A matroid is first decomposed into maximal 3‐connected minors called atoms and the original matroid is graph‐realizable if and only if all the atoms are graph‐realizable. Each atom is reduced to a wheel or a whirl matroid by reduction and contraction operations. The graph‐realizability of an atom is tested at each step of the reconstruction process. Two examples are included to illustrate the algorithm.
A REVIEW OF RECENT WORK IN JAPAN ON PRINCIPAL PARTITIONS OF MATROIDS AND THEIR APPLICATIONS1
Authors: Iri Masao
Published: December 2006

Summary

The principal partitions of graphs and matroids have many useful applications in engineering systems analysis and information theory. The partitions are based on the nonuniform distribution of the ranks of the minors of a matroid. This paper outlines the research carried out in Japan during the last decade with motivations from various fields of engineering science.
The Ultimate Enigma of “Clever Hans”: The Union of Nature and Culture
Authors: SEBEOK THOMAS A.
Published: December 2006

Tell me, where is fancy bred,

or in the heart or in the head?

How begot, how nourished?

Reply, reply.

–The Merchant of Venice
STRUCTURE AND FUNCTION OF H+‐ATPase: WHAT WE HAVE LEARNED FROM Escherichia coli H+‐ATPase*
Authors: Kanazawa Hiroshi , Futai Masamitsu
Published: December 2006

We have identified a transducing phage λasn5 carrying a set of structure genes coding for F1FO. New transducing phages and plasmids carrying a part of the DNA fragment in λasn5 were isolated and assayed by genetic complementation with mutants of F1FO. After analysis of DNA from these phages and plasmids, we mapped the genes for F1FO within a physically defined segment of DNA of 4.5 megadaltons. The nucleotide sequence of the DNA segment was determined, and the primary amino acid sequences of all the subunits were determined. We discuss the homology of the sequence with those of other proteins capable of nucleotide binding. The secondary structures of the subunits were deduced, and a Rossman fold was found in the β‐subunit. The b‐ and δ‐subunits had unique secondary structures.

The roles of the subunits of F1 were studied by analysis of isolated subunits and mutationally altered subunits. Conformational changes of the α‐ and β‐subunits and transmission of conformational change between the two subunits were observed. Intracistronic mapping of mutations was achieved.
STATIC AND TIME‐RESOLVED STRUCTURAL STUDIES OF THE Ca2+‐ATPase OF ISOLATED SARCOPLASMIC RETICULUM
Authors: Blasie J. K. , Herbette L. , Pierce D. , Pascolini D. , Scarpa A. , Fleischer S.
Published: December 2006

X‐ray and neutron diffraction studios of oriented multilayers of isolated light sarcoplasmic reticulum (SR) have provided the separate profile structures of the lipid bilayer and the Ca2+‐ATPase molecule within the membrane profile to ˜10 Å resolution. These studies utilized biosynthetically deuterated SR phospholipids incorporated isomorphously into the isolated SR membranes via exchange proteins.

Time‐resolved x‐ray diffraction studies of these oriented SR membrane multilayers have indicated that significant changes occur in the membrane profile structure within a single turnover of the Ca2+‐transport cycle. These studies utilized the flash photolysis of caged ATP to effectively synchronize the ensemble of Ca2+‐ATPase molecules in the multilayer, synchrotron x‐radiation to provide 100‐ to 500‐millisecond data collection times, and double‐beam spectrophotometry to monitor Ca2+ transport in the oriented SR membrane multilayer.
Early Hemopoietic Differentiation: The Action of Multi‐CSF Is Complemented by Lineage Specific Growth Factors
Authors: MIGLIACCIO GIOVANNI , MIGLIACCIO ANNA RITA
Published: December 2006

Although mechanisms controlling differentiation of hemopoietic stem and early progenitor cells are still poorly understood, it is generally conceded that a pivotal role is played by hemopoietic growth factors (HGFs).1,2 However, in‐vitro analysis of their action on early progenitors may be obscured by cell‐cell interaction, as well as by the presence of fetal bovine serutn (FBS). To overcome these limitations, we investigated the action of pure multipotent or lineage‐specific HGFs on purified progenitors grown in FBS‐free cultures.

In the murine system, highly purified progenitors were cultured in the presence of multipotent colony‐stimulating factor (multi‐CSF, also termed interleukin‐3), erythropoietin (Ep) and macrophagic‐CSF (M‐CSF). Each HGF was unable by itself to induce significant colony growth. However, combined addition of multi‐CSF and either Ep or M‐CSF gave rise only to pure erythroid or macrophagic colonies, respectively.

Partly purified human progenitors were challenged by human granulomonocytic‐CSF (GM‐CSF), pluripotent CSF (PPO, also termed granulocytic‐CSF, G‐CSF) and Ep. Here again, each HGF was unable per se to promote colony growth, but combined addition of GM‐CSF or PPO and Ep gave rise only to pure erythroid colonies.

These results support a model of early hemopoietic differentiation according to which multi‐lineage HGFs represent “competence” GFs, the action of which is complemented by lineage‐specific “progression” HGFs.
Where Do Different Neurons Come From?
Authors: McKAY RON
Published: December 2006

The ability to make functionally competent brain precursor cell lines may have important consequences for a number of outstanding questions in mammalian CNS development. The diversity of neurons is one of the most striking conclusions of recent molecular studies of the nervous system. In our work we provided some of the earliest data to support this conclusion.30‐32 Our preliminary data with precursor cell lines suggest that these cells give neurons with highly differentiated characteristics. If further work continues to support this conclusion, then immortal cell lines will be useful in analyzing the mechanisms that make neurons different. The methods that can be applied to these cell lines include manipulation in tissue culture, transplantation into the developing CNS, and application of the methods of mammalian cell genetics to link gene function to neuronal specificity.
The Moral Arguments against Military Research
Authors: ROTH BERNARD
Published: December 2006

Insanity in individuals is something rare‐but in groups, parties, nations, and epochs, it is the rule.

Friedrich Nietzsche

Military research has become part of the established order in scientific inquiry throughout the world. Because of the awesome power of the military arsenals and the potential for ending or altering many forms of life, the questions associated with military research cannot be regarded as purely scientific or political. More than in any previous period of history, the issues associated with military research have become a moral problem. It is argued that the moral responsibilities of scientists are not altered because a country has a more democratic form of government. In fact, scientists with the most personal freedom should be the ones pressing the moral arguments against military research. It is further argued that research tends to follow paths pointed out by authorities, and when that authority is the military the research will always have unwanted side effects that are immoral and counterproductive for the scientific enterprise and the well‐being of the citizenry of that country. The problems raised by military research bring to the fore basic issues associated with the appropriate size and funding of a country's scientific enterprise, and the question of how best to achieve the goals associated with that enterprise.
Calculability of the Flavor‐Mixing Parametersa
Authors: KANG KYUNGSIK
Published: December 2006

Despite the impressive success of the standard model, the repetition of the family‐generation of leptons and quarks persists as one of the most challenging unresolved problems in particle physics. The fermion family problem is to understand the fermion mass hierarchy of the leptons and quarks as observed in family‐generations. Any consistent solution to this problem should also describe the flavor mixings in the charged‐current sector including the CP‐invariance violation as well as the empirical flavor‐conservation up to the αGf order in the neutral weak interaction sector. In the standard model the fermion masses are generated by spontaneous breaking of the electroweak symmetry via the Higgs mechanism, but they are arbitrary free parameters. In other words, the standard model can be adjusted to accommodate the fermion family‐generations but lacks calculability for the fermion mass spectrum. Because there are several fermion generations, the weak interaction eigenstates are not necessarily the mass eigenstates and therefore there will inevitably be mixings between different flavor states in the charged current sector thus introducing further arbitrary parameters to the standard model. However, the neutral‐current sector is flavor diagonal up to αGf order in the standard model because the fermions in each generation are assigned in the same dimensional representations.
Regulation of Cell Proliferation: The Negative Control Perspectivea
Authors: SOTO ANA M. , SONNENSCHEIN CARLOS
Published: December 2006

Nothing in Biology makes sense except in the light of evolution.

Theodosius Dobzhansky
κ‐Structures: Cardinality Conditions, Compactness, Metrization
Authors: HODEL R. E.
Published: December 2006

The notion of a κ‐structure on a set E is introduced as a generalization of a topology on E. Pospíšil's inequality |X|≤d(X)χ(X), Arhangel'skiĭi's inequality |X|≤ 2L(X)χ(X), and Gryzlov's inequality |X|≤ 2ψ(X) for X compact all extend to κ‐structures. Chaber's theorem, that every countably compact space with a Gδ‐diagonal is compact, also extends to κ‐structures. Two metrization theorems in terms of κ‐structures are given.
Pseudocompactness, Measurability, and Category in Compact Groups
Authors: ITZKOWITZ GERALD L.
Published: December 2006

It is shown that in the case where G is a compact topological group satisfying certain standard cardinality conditions, a theorem of Wilcox implies that it is possible to partition G into a collection of dense subsets, whose cardinality is Card(G), where each subset is pseudocompact. Thus each subset is of the second category in G, each subset is nonmeasurable, and each has Haar outermeasure one in G. This result simultaneously extends classical results of Ulam and Sierpinski on the partition of a perfect space into sets of category two and of Kakutani and Oxtoby on the partition of a compact metric group into nonmeasurable subsets of full Haar outermeasure. A useful proposition that in a compact group a subset has outermeasure one iff it meets every closed Gδ with positive Haar measure in the group is proved. This proposition is an important tool used in the proof of the theorem concerning partitions.
Quasi Uniformities Defined by Sets of Neighborhoodsa
Authors: KÜNZI HANS‐PETER A.
Published: December 2006

Those ordered topological spaces (X, 𝒯, ≤), for which the set of all 𝒯×𝒯‐neighborhoods of the partial order ≤ forms a quasi uniformity that determines (X, 𝒯, ≤), are studied. The investigations are motivated by the following problem posed by P. Fletcher and W. F. Lindgren: For which quasi‐uniform spaces (X, 𝒰) is the family of all 𝒯(𝒰*×𝒰*)‐neighborhoods of ∩𝒰 a quasi uniformity compatible with 𝒯(𝒰)?
Maximal Chains in Function Spaces
Authors: VAINIO REINO
Published: December 2006

It is proved i‐space compatibility for ordered convergence spaces (every maximal chain inherits its own interval topology) is closed under formation of arbitrary products. Some related results (a Dini theorem) for spaces of continuous functions from arbitrary convergence spaces to lattices endowed with order convergence are obtained.
New Developments in the Synthesis of Natural and Unnatural Amino Acids
Authors: KAMPHUIS J. , MEIJER E. M. , BOESTEN W. H. J. , SONKE T. , van den TWEEL W. J. J. , SCHOEMAKER H. E.
Published: December 2006

Amino acids play an important role in biochemistry and chemistry. They are the building blocks of proteins and play an essential role in the regulation of the metabolism of living organisms.

In general, it can be stated that microbial processes (fermentation) are the industrial production methods of choice for large‐scale production of naturally occuring proteinogenic L‐α‐H‐amino acids, while for the production of synthetic D‐ and/or L‐α‐H‐amino acids, several other methods are highly competitive.

At DSM, several routes, i.e., (chemoenzymatic) synthesis, towards L‐α‐H and D‐α‐H‐amino acids have been elaborated since the midseventies.

A general process for the synthesis of natural as well as synthetic optically pure amino acids has been developed, using an enzymatic kinetic resolution step on racemic amino acid amides as the key step. In this case, both enantiomers of the α‐H‐amino acids are prepared in one single step. This process has been commercialized since 1988.

More recent developments using L‐ or D‐amino peptidases in combination with amino acid amide racemases and an asymmetric transformation concept are discussed.
βNa
Authors: DOW ALAN
Published: December 2006

A brief overview is given of those aspects of the study of βN, the Stone‐Čech compactification of the integers, which are most closely connected with Mary Ellen Rudin's considerable contributions in this area. Orderings of the ultrafilter types are discussed, a topological dynamics‐based presentation of the construction of incomparable types is given, as is an application involving Blass's principle NCF to the Scarborough‐Stone problem.
Preface
Authors: NITSCH ROGER M. , CORKIN SUZANNE , GROWDON JOHN H. , WURTMAN RICHARD J.
Published: December 2006

This volume contains the papers and poster abstracts compiled for the seventh meeting of the International Study Group on the Pharmacology of Memory Disorders Associated with Aging (ISG), that took place in Zürich, Switzerland, on February 12–14, 1993. The ISG was founded 14 years ago in the belief that the development of effective treatments for Alzheimer's disease (AD) and other dementias would be accelerated by periodic meetings of scientists and physicians from around the world who are actively working on issues related to dementia. There have been six previous “Zurich Meetings”—in 1979, 1981, 1984, 1987, 1989, and 1991. The proceedings of the second ISB meeting were published by Raven Press in 1982 (Alzheimer's Disease: A Report of Progress in Research; Corkin, Davis, Growdon, Usdin, and Wurtman, editors); the proceedings of the fourth ISG meeting were published by Springer‐Verlag in 1988 as Supplement 24 of the Journal of Neural Transmission (Topics in the Basic and Clinical Science of Dementia; Wurtman, Corkin, and Growdon, editors); the proceedings of the fifth ISB meeting were published by Raven Press in 1990 (Alzheimer's Disease, Advances in Neurology, Volume 51; Wurtman, Corkin, Growdon, and fitter‐Walker, editors); and the proceedings of the sixth ISG meeting were published by the New York Academy of Sciences in 1992 (Aging and Alzheimer's Disease, Volume 640; Growdon, Corkin, fitter‐Walker, and Wurtman, editors).
Principles of Synaptic Transmissiona
Authors: MOORE ROBERT Y.
Published: December 2006

Neurons in the central nervous system communicate almost exclusively by the production and release at synapses of a series of molecules that are designated transmitters. Three such molecules make up the major transmitters, GABA, glutamate, and acetylcholine. GABA neurons are the principal inhibitory neurons and, as such, are the major local circuit neurons of the brain. They also are projection neurons in a number of systems. Glutamate neurons are excitatory projection neurons, particularly of the cerebral cortex, thalamus and retina. Acetylcholine neurons are excitatory neurons in ascending brainstem and basal forebrain systems and in cranial and spinal motor neurons and neurons of the sympathetic and parasympathetic systems. The catecholamines, dopamine and norepinephrine, are transmitters in several systems in brain. Dopamine is present in midbrain neurons projecting to the neostriatum, basal forebrain and cerebral cortex. It is also produced by hypothalamic neurons projecting to the median eminence and pituitary. These systems are highly topographically organized in contrast to the norepinephrine systems. The locus coeruleus norepinephrine system projects principally to thalamus, cerebral cortex and cerebellar cortex whereas the lateral tegmental system projects primarily to basal forebrain, hypothalamus, brainstem and spinal cord. The serotonin neurons of the brainstem raphe also project widely over the neuraxis, midbrain raphe neurons primarily to diencephalon and telencephalon and pontine medullary neurons to brainstem and spinal cord. There are smaller neuronal groups that produce glycine or histamine.

At the present time, it appears that most, if not all, CNS neurons produce one of these small molecule transmitters. In many instances, these molecules are colocalized with one or more peptides that appear to modify the postsynaptic action of the small molecule transmitter.
The Amyloid Precursor Protein in Ischemic Brain Injury and Chronic Hypoperfusiona
Authors: KALARIA R. N. , BHATTI S. U. , LUST W. D. , PERRY G.
Published: December 2006

We studied changes in the spatial and temporal distribution of the β amyloid precursor protein (APP) of Alzheimer's disease (AD) in experimental ischemic brain injury. Rats with repeated reversible occlusions of one middle cerebral artery showed striking APP reactivity in astrocytic processes in perifocal regions and adjacent white matter. APP reactive dystrophic axons and neurons were also evident in the cortex and hippocampus ipsilateral to the MCA occlusion. Such changes were similarly apparent in animals subjected to partial forebrain ischemia induced by bilateral occlusion of the carotid arteries. Our studies suggest that focal ischemic insults or chronic hypoperfusion leads to increased accumulation or induction of APP in surviving cellular elements that may relate to the processes involved in β amyloid deposition in AD.
Basal Forebrain Grafts in the Hippocampus and Neocortex: Regulation of Acetylcholine Releasea
Authors: NILSSON OLA G. , LEANZA GIAMPIERO , ROSENBLAD CARL , BJÖRKLUND ANDERS
Published: December 2006

The regulation of acetylcholine (ACh) release from cholinergic neurons transplanted to the hippocampus or neocortex was studied by microdialysis in awake rats. Fetal basal forebrain tissue was implanted as a cell suspension or solid graft into the fimbria‐fornix‐lesioned hippocampus, or as a cell suspension into the frontal cortex after excitotoxic lesion of the nucleus basalis. Several months after transplantation, microdialysis probes were implanted in areas of the hippocampus or frontal cortex reinnervated by the grafts. The grafts restored lesion‐induced deficits in steady‐state ACh release up to normal or above normal levels in both hippocampus and frontal cortex. The responses to KCl and tetrodotoxin suggested that the ACh release exhibited normal firing‐dependent properties. By applying various behaviorally arousing stimuli that normally activate the basal forebrain projection systems, we wished to investigate the functional integration of the grafts in the host brain. In the hippocampus, sensory stimulation, immobilization stress and motor activity all resulted in increased release of graft‐derived ACh amounting to 25–65% of the normal response. Variations in ACh levels during the day‐night cycle was, however, not observed in the grafted rats. In the frontal cortex, immobilization enhanced the graft‐derived ACh release (60% of normal response), whereas the response to sensory stimulation did not reach significance. Since the activity of the normal basal forebrain projection systems is under influence of monoaminergic brainstem afferents, we investigated the effects of systemic administration of amphetamine or apomorphine on ACh release in the hippocampus. Both drugs produced increases in graft‐derived ACh release although the response was variable and less pronounced than normal. In conclusion, the graft‐derived ACh release was affected by behavioral manipulations and catecholaminergic drugs that normally modify cholinergic septo‐hippocampal and basalo‐cortical activity. This strongly suggests a high degree of functional integration of the graft in the host brain allowing for a regulated release of transmitter that can be adjusted during ongoing behavior.
Cells Engineered to Produce Acetylcholine: Therapeutic Potential for Alzheimer's Diseasea
Authors: FISHER LISA J. , RAYMON HEATHER K. , GAGE FRED H.
Published: December 2006

Alzheimer's disease (AD) is a debilitating disorder of the central nervous system which may affect up to 50% of the population over the age of 85 years. The etiology of AD is unknown and there is currently no cure for the disease. Well‐documented losses in cholinergic and other neurotransmitter systems have provided a focal point for attempting pharmacological interventions in AD to ameliorate some of the cognitive deficits that occur. However, current systemic strategies have met with limited success. An alternative strategy, that has been pursued in animal models of neurodegenerative disease, is to augment neurotransmitter function within the brain through tissue transplantation. Such implants have an advantage over conventional drug therapies in that the cells can be precisely placed within compromised areas of the brain. We have pursued a strategy of designing cells, through the use of molecular biology techniques, to produce neurotrophic factors and neurotransmitters. Recently, we developed a primary fibroblast cell line that was genetically modified to express choline acetyltransferase (ChAT). In vitro, these cells produced and released acetylcholine at levels that varied with the amount of choline in the culture media. When implanted into the hippocampus of rats, the in vivo microdialysis technique revealed that the ChAT‐expressing fibroblasts continued to produce and release acetylcholine after grafting. Most importantly, the levels of acetylcholine synthesized by the cells could be regulated by the localized infusion of choline in the vicinity of the grafts. These results confirmed previous work which indicated that engineered fibroblasts provide an effective delivery vehicle of different substances to the brain. While the intracerebral implantation of genetically modified cells will not cure AD, the continuing development of this strategy may ultimately provide a powerful approach for ameliorating the devastating cognitive impairments which are a hallmark of this disease.
Natural and Synthetic Huperzine A: Effect on Cholinergic Function in Vitro and in Vivoa
Authors: HANIN ISRAEL , TANG XI‐CAN , KINDEL GISELA L. , KOZIKOWSKI ALAN P.
Published: December 2006

Huperzine A has been shown to be useful in the treatment of symptoms of dementia of the Alzheimer type. Our initial attempts to synthesize (‐)Huperzine A resulted in the racemic mixture of (−)Huperzine A. We have therefore compared the in vitro and in vivo effects of (±)Huperzine A with those of (−)Huperzine A in rats. The results indicate a similar biological mechanism of action between the two, but that the racemic mixture of (±) Huperzine A has a weaker biological activity than the natural product (−)Huperzine A, presumably due to the presence in the mixture of (+)Huperzine A, which is considerably less potent than the (−)isomer.
Gangliosides and Neurotrophic Factors in Neurodegenerative Diseases: From Experimental Findings to Clinical Perspectives
Authors: FUSCO M. , VANTINI G. , SCHIAVO N. , ZANOTTI A. , ZANONI R. , FACCI L. , SKAPER S. D.
Published: December 2006

A large body of experimental data suggests that neurotrophic molecules and/or substances that facilitate their action could be pharmaceutical agents for neurodegenerative pathologies. In particular, it has been demonstrated that nerve growth factor (NGF) exerts a physiological role for forebrain cholinergic neurons, while brain‐derived neurotrophic factor (BDNF) seems to play a relevant role in rescuing dopaminergic neurons following damage. In addition, gangliosides are reported to potentiate neurotrophic factor effects in vitro as well as in vivo. In this study we examined the effects of the monosialoganglioside GM1 in different experimental models. The responsiveness of forebrain cholinergic neurons following NGF ± GM1 was evaluated by assessing choline acetyltransferase (ChAT) activity in hippocampus, septal area and striatum of behaviorally impaired 24‐month‐old rats. NGF was intracerebroventricularly (i.c.v.) infused for 2 weeks while GM1 was given systemically for 3 weeks, starting from the beginning of NGF infusion. Moreover, the possible protective effects of GM1 were assessed following exposure of cultured cerebellar granule cells and dopaminergic mesencephalic neurons to different doses of 6‐OH‐DOPA, a metabolite of the dopamine pathway which has excitotoxic properties and has been hypothesized to participate in the pathology of Parkinson's disease. GM1 treatment to aged rats was seen to potentiate the NGF‐induced increase of ChAT activity in the striatum ipsilateral to the NGF infusion. Moreover, in the striatum contralateral to the NGF infusion, GM1 increased ChAT activity above the control values, whereas NGF treatment alone did not affect enzymatic activity. GM1 treatment of cerebellar granule cells and mesencephalic neurons counteracted the dose‐and time‐dependent neurotoxidty of 6‐OH‐DOPA. These data support the notion that GM1 might prove useful in treating those pathological conditions where trophic factor deficits and/or cxcitotoxin‐related toxicity play an important role.
Effect of CDP‐Choline on Cognition and Immune Function in Alzheimer's Disease and Multi‐Infarct Dementiaa
Authors: CACABELOS R. , ALVAREZ X. A. , FRANCO‐MASIDE A. , FERNÁNDEZ‐NOVOA L. , CAAMAÑO J.
Published: December 2006

The cholinergic dysfunction present in Alzheimer's disease (AD) might be due to a specific vulnerability of cholinergic neurons linked to neurotrophic imbalance, neuroimmune impairment, and/or direct effects of β‐amyloid deposition and NFT formation in ACh neurons. The presence of abnormal epitopes exposed on neuronal membranes may contribute to the activation of resting microglia initiating a neuroimmune cascade leading to cell destruction. According to this hypothesis, a multifactorial treatment in AD should produce: 1) inhibition of β‐amyloid and NFT formation; 2) restoration of neuronal membrane integrity; and 3) control of neuroimmune auto‐aggression. Since interleukin‐1 (IL‐1) is an APP gene promoter showing a progressive increase in body fluids in parallel with mental deterioration in AD patients, we have studied the effects of CDP‐choline on cognition, several biological parameters, and IL‐1β production in AD and multi‐infarct dementia (MID) in order to elucidate whether this compound alone or in combination with other drugs is able to restore immune function and improve mental performance in senile dementia.
Summary of Recent Developments in Primordial Nucleosynthesis*
Authors: SCHRAMM DAVID N.
Published: December 2006

This paper summarizes the recent observational and theoretical results on Big Bang Nucleosynthesis. In particular, it is shown that the new Pop II 6Li results strongly support the argument that the Spite Plateau lithium is a good estimate of the primordial value. The 6Li is consistent with the Be and Be found in Pop II stars, assuming those elements are cosmic ray produced. The HST 2D value tightens the 2D arguments and the observation of the 3He in planetary nebula strengthens the 3He +2D argument as a lower bound on Ωb. The new low metalicity 4He determinations slightly raise the best primordial 4He number and thus make a better fit and avoid a potential problem. The quark‐hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ωb are possible vis‐à‐vis the homogeneous model; hence, the robustness of Ωb∼ 0.05 is now apparent. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ωb∼ 1 seems to be definitely excluded, so, if Ω= 1, as some recent observations may hint, then non‐baryonic dark matter is required.
H‐Enrichments and Their Homeomorphism Groups II
Authors: BANKSTON PAUL
Published: December 2006

ABSTRACT. H‐enrichments of topologies are larger (i.e., inclusive) topologies that also have larger homeomorphism groups. The study of H‐enrichments of the Euclidean and rational topologies via generalized Baire category arguments is continued. New results concern lower bounds on the number of H‐enrichments, connectedness, and separation properties of such topologies and certain of their cardinal invariants.
The Cardinal Number d and Convergent Sequences in Q
Authors: FAST STEPHEN H.
Published: December 2006

ABSTRACT. The cardinal number d is defined such that N1 |Ml b |Ml d |Ml c. It is shown that d is the minimum cardinality of a sequential cover of the space of the rational numbers with the usual topology.
Sequentially Compact Cancellative Topological Semigroups: Some Progress on the Wallace Problema
Authors: GRANT DOUGLASS L.
Published: December 2006

ABSTRACT. Some results of Mukherjea and Tserpes are generalized by showing that any sequentially compact, cancellative topological semigroup is a topological group. Hence, any countably compact, cancellative topological semigroup with any additional condition that would imply sequential compactness is also a topological group. Finally, it is shown that any w‐bounded, cancellative topological semigroup is also a topological group.
Perfect κ‐Normality of Product Spaces
Authors: OHTA HARUTO , SAKAI MASAMI , TAMANO KEN‐ICHI
Published: December 2006

ABSTRACT. A space X is called perfectly K‐normal (respectively, Klebanov) if the closure of every open set (respectively, every union of zero‐sets) in X is a zero‐set. It is proved: The product of infinitely many Lašnev spaces need not be perfectly K‐normal, in particular, S(ω1)2χ Dω1 is not perfectly K‐normal; a locally compact, paracompact space Y is Klebanov if and only if XχY is perfectly K‐normal for every Lašnev space X; if XχY is perfectly K‐normal for every paracompact s̀‐space X, then Y is perfectly normal. Properties of a Klebanov space are also studied.
K‐Structures and Topology
Authors: HODEL R. E.
Published: December 2006

ABSTRACT: K‐structures allow one to give purely set‐theoretic proofs of a number of important inequalities in cardinal functions. We explore the precise relationship between K‐structures, closure spaces in the sense of Čech, spaces with the weak topology in the sense of Arhangelskiǐ, and topological spaces. We also introduce the notion of a basic proximity space and establish the connection between K‐structures and basic proximity spaces.
Determining a Weakly Locally Compact Group Topology by Its System of Closed Subgroups
Authors: COMFORT W. W. , SOUNDARARAJAN T. , TRIGOS‐ARRIETA F. J.
Published: December 2006

ABSTRACT: Definition: A topological group G is weakly locally compact if (i) G is locally bounded and (ii) for every closed, Gδ subgroup H of G the quotient space G/H is locally compact. The authors show:

Theorem: A Hausdorff topological group G is weakly locally compact if and only if some pseudocompact subset of G has nonempty interior (i.e., G is locally pseudocompact).

This characterization generates the following result, which is motivated by a question posed by K. A. Ross [Fundamenta Mathematicae, 1965, 56: 241–244].

Theorem: If T1 and T2 are weakly locally compact group topologies on an Abelian group G such that 〈G,T1〉 and 〈G,T2〉 have the same closed subgroups, and if T1, T2, then T1=T2.
Nonproduct Group Topologies for Rn
Authors: STEVENS T. CHRISTINE
Published: December 2006

ABSTRACT: We prove that, for every integer n≥ 2, there is a metrizable group topology Un for the additive group Rn such that Un is strictly weaker than the usual topology but every straight line in Rn inherits the usual topology from Un. The topology Un is intrinsically a “non‐product” topology for Un in the sense that, no matter how one decomposes Rn as a product of n copies of R, Un will not be the product of the topologies that it induces on these factors.
On the Weak Topology in Operator Algebras
Authors: CHU CHO‐HO
Published: December 2006

ABSTRACT: We study two properties in C*‐algebras relating to the weak convergence of sequences.
On the origin of halo globular clusters and spheroid stars
Authors: VIETRI MARIO , PESCE ENRICO
Published: December 2006

A scenario is presented for the simultaneous formation of halo globular clusters and spheroid stars, in which shocks occuring in the gaseous, primordial (Z= 0) Galaxy play the central role. Denser‐than‐average subcondensations are shown to cool quickly and implode. Small condensations (M < Mt= 5 × 104M⊙) are returned to the hot surrounding phase by the reflected shock, large ones (M > Mu= 2 × 107M⊙) fragment into stars in the dense shell behind the implosion shock, thus generating the first spheroid stars. Intermediate clouds, suddenly cooling to 100K because of collisional H2 excitation, are compressed and left in approximate pressure equilibrium with the hot medium: they give rise to halo GCs. The dependence of the proposed formation mechanism upon overall galactic metallicity and galaxy rotation velocity is weak, so that a universal upper mass limit is deduced. A mass range for halo GCs (2 × 103– 6 × 105M⊙) and a velocity dispersion for spheroid stars in agreement with observations are predicted.
The Density of the Universe from the Peculiar Velocities of Sc Galaxies
Authors: Freudling Wolfram , Da Costa Luiz N. , Giovanelli Riccardo , Haynes Martha P. , Salzer John J. , Wegner Gary
Published: December 2006

The all‐sky survey of Sc galaxies with estimated redshift–independent distances presented by Haynes et al. (1993) is used to map the peculiar velocity field in the local universe. After suitable correction for Malmquist and selection biases, the resulting peculiar velocities are used to estimate the mass density in the local universe using the POTENT method (Dekel 1994). The resulting density field is compared with the distribution of galaxies.
Neuropsychology of Post‐Polio Syndrome
Authors: GRAFMAN JORDAN , CLARK KIM , RICHARDSON DAVID , DINSMORE STEVE , STEIN DANIEL , DALAKAS MARINOS C.
Published: December 2006

The sparse literature concerning the psychology of PPS is easy to summarize. Some psychopathology can be observed in PPS, but it is not clear whether it is a reaction to PPS or a by‐product of a concurrent but unrelated disorder. Psychopathology does not seem to be responsible for the onset or intensity of new PPS symptoms. A relationship may exist between the perception of stress, an inability to handle stress, and perceived fatigue in PPS. Neuropsychological studies have been equivocal with patients performing well on some tests and more poorly on others compared to controls. An attempt has been made to link reticular formation and hypothalamic involvement in PPS to decreased attention and arousal and increased fatigue. Higher levels of fatigue have been associated with the presence of hyperintensities on MRI scanning. Unfortunately, a variety of methodological problems are present with most of these studies and indicate that caution should be used in their interpretation (see section on Methodological Considerations).

Future studies should adapt more stringent controls in subject selection so that non‐PPS factors that might affect behavior or cognition can be factored out (e.g., hypertension or exogenous depression). Tests specifically designed to evaluate components of attention and motor control can be used to test hypotheses regarding fatigue, arousal, and attention. Our experience is that patients carefully selected to have pure PPS without concurrent medical disease have few complaints about cognition or altered mood. Before we pronounce neuropsychological deficits in PPS patients, more carefully designed studies are required.
Mechanisms and Functions of Serotonin Neuronal Systems
Authors: FULLER RAY W.
Published: December 2006

Serotonin (5‐hydroxytryptamine) was discovered to be present in brain in 1953 and soon thereafter was correctly postulated to serve as a neurotransmitter or neuromodulator. The original mapping of serotonin neurons in the central nervous system (CNS) in the 1960s provided some insight into their possible physiological roles.1 The development of drugs that modify serotonin function in specific ways has helped in understanding the numerous functions of serotonin neurons and their operation.
Functional Imaging Patterns in Alzheimer's Disease Relationships to Neurobiologya
Authors: JAGUST W. J.
Published: December 2006

Brain imaging with functional techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) have been widely applied to the study of dementia. While the pattern of temporal and parietal hypometabolism and hypoperfusion have often been suggested to be of diagnostic utility in ascertaining that a dementia is due to Alzheimer's disease (AD), the exact sensitivity and specificity of this pattern in clinically important situations is unclear. These imaging findings have been of considerable interest, however, in describing the regional patterns of predilection in the disease. Evidence supports the contention that the earliest sites of functional impairment in AD are in the temporal lobes. Surprisingly, however, mesial temporal lobe hypometabolism was difficult to detect in a group of mildly demented AD patients in comparison to a group of healthy older subjects. These results suggest that simple use of mesial temporal lobe metabolic rates as a diagnostic for AD may not be fruitful, and that evaluation of the earliest stages of AD can be most productively studied by investigating healthy older individuals.
Neurotrophic and Neuroprotective Effects of hAPP in Transgenic Micea
Authors: MUCKE L. , ABRAHAM C. R. , MASLIAH E.
Published: December 2006

To better understand the role the human amyloid precursor protein (hAPP) plays in Alzheimer's disease (AD), it is essential to define its primary function(s). Here we expressed different hAPPs in neurons of transgenic (tg) mice to characterize their effects on the intact central nervous system (CNS). Immunolabeled brain sections of tg and non‐tg mice were compared quantitatively by microdensitometry and computer‐aided analysis of laser scanning confocal digitized images. Compared with non‐tg mice, tg mice overexpressing hAPPs showed an increase in the number of synaptophysin immunoreactive presynaptic terminals as well as in the expression of the growth‐associated marker GAP‐43. While non‐tg controls and tg mice expressing hAPP751 at moderate levels displayed a normal pattern of reinnervation of the dentate gyrus following perforant pathway transection, tg mice expressing hAPP695 at severalfold higher levels showed an accentuation of the synaptic loss and no sprouting reaction. In addition, expression of hAPP751 at moderate levels effectively protected neurons against excitotoxic injury induced either acutely by systemic injection of kainic acid or chronically by transgene‐driven glial production of the soluble HIV‐1 protein gp120. Neuronal expression of hAPP695 at higher levels provided less excitoprotection. Our findings are consistent with the postulate that APP plays a role in the formation/maintenance of synapses and that processes which affect this function could contribute to the synaptic pathology seen in AD. Our study also revealed that hAPPs can exert important excitoprotective functions in vivo and that the efficiency of this protection may depend on the hAPP isoform expressed as well as on the level of neuronal hAPP expression. Neuronal overexpression of hAPP beyond a certain level may have detrimental effects on the CNS, particularly in the context of secondary neural injuries.
Cellular Signaling Pathways and Cytoskeletal Organization
Authors: KOSIK K. S. , QIU W. Q. , GREENBERG S.
Published: December 2006

We describe a possible mechanism by which the amyloid precursor protein (APP) may be linked to the intraneuronal pathology of Alzheimer's disease (AD). Extracellular proteolytic products of APP may directly or indirectly transduce signals to cells under normal as well as pathological conditions. This activity appears to reside in the cysteine‐rich amino terminus of APP. How APP or its metabolic products may affect the phosphorylation of tau is considered.
Clinical and Neuropathological Correlates of Apolipoprotein E Genotype in Alzheimer's Disease ‐ Window on Molecular Epidemiologya
Authors: HYMAN B.T. , GOMEZ‐ISLA T. , WEST H. , BRIGGS M. , CHUNG H. , GROWDON J.H. , REBECK G.W.
Published: December 2006

Inheritance of the apolipoprotein E (apo E) ε4 allele has recently been found to be associated with Alzheimer's disease. We have studied the clinical and neuropathological correlates of apolipoprotein E genotype in a large group of Alzheimer's patients. The primary influence on clinical presentation is a shift towards earlier age of onset in individuals who have the apo E ε4 gene: no change in clinical course was observed. In neuropathological studies, we find that the major influence of apo E ε4 is on increased Aβ deposition. These results led to a model of the biological interaction between the apo E protein and Alzheimer's disease.
β‐APP Cognitive Function versus β‐Amyloid–induced Cell Death
Authors: GSCHWIND M. , MARTIN J. R. , MOREAU J.‐L. , HUBER G.
Published: December 2006

The β‐amyloid precursor protein (β‐APP) has been hypothesized to play an important role in the establishment of synaptic connections. Icv injections of anti‐βAPP antibodies into rat brains produced no appreciable effect on subsequent learning of a passive avoidance task whereas memory assessed 1 day later in a retention test was impaired in anti‐β‐APP– but not control‐IgG–injected animals. This suggests a possible involvement of β‐APPs in cognitive functions. In order to evaluate the properties of the proteolytic Aβ‐fragment accumulating in Alzheimer's disease brains, four different neuronal cell types were exposed to Aβ1–42 for 24 hours. All cells degenerated in response to Aβ, yet chromosomal condensation and internucleosomal DNA fragmentation, typical for apoptosis, occurred in only three of the cell types tested. These findings suggest that β‐APPs may play an important role in cognitive processes and additionally, that their alternative proteolytic product Aβ may be differentially toxic to neuronal cell types, inducing cell death either by necrosis or by apoptosis.
Differential Regulation of APP Secretion by Apolipoprotein E3 and E4a
Authors: WOLOZIN B. L. , BASARIC‐KEYS J. , CANTER R. , LI Y. , VANDERPUTTEN D. , SUNDERLAND T.
Published: December 2006

The apolipoprotein E isozyme, apolipoprotein E4, has been implicated as a risk factor for Alzheimer's disease. One reason for the increased risk may be that apolipoprotein E binds to the Aβ peptide, but there may be other factors as well. We show that apolipoprotein E is a potent regulator of the secretion of amyloid precursor protein. In cultures of PC12 cells, nanomolar levels of apolipoprotein E3 induce a rapid decrease in the secretion of APP, being observable in 30 min. and stable over 24 hours. Apolipoprotein E4, in contrast, increases secretion of APP over a similar time course. Reciprocal changes occur in cellular amyloid precursor protein. Differential characteristics are also seen in apo E binding to the cells, where apo E4 binds over a slower time course than apo E3. These results suggest a novel mechanism by which apolipoprotein E may be influencing the metabolism of amyloid precursor protein.
Brain Glucose Metabolism Is Controlled by Amplification and Desensitization of the Neuronal Insulin Receptora
Authors: HOYER S. , HENNEBERG N. , KNAPP S. , LANNERT H. , MARTIN E.
Published: December 2006

Glucose metabolism is essential for brain function and structure. Glucose contributes to the formation of neurotransmitters and is normally the only source for energy formation. There is increasing evidence that brain glucose metabolism is under control of the neuronal insulin/insulin receptor signal transduction. The present data clearly show that intracerebroventricularly administered insulin exerts anabolic effects on cerebral glucose/energy metabolism (amplification of the neuronal insulin receptor complex) whereas cortisol (corticosterone) acts antagonistically (desensitization of the neuronal insulin receptor complex). It is also shown that short‐term cortisol (corticosterone) enhanced energy turnover in temporoparietal corfex and hippocampus. In contrast, long‐term cortisol (corticosterone) reduced energy turnover in both brain structures studied. This metabolic pattern is reminiscent of that found in very old age. Therefore, it is assumed that long‐term cortisol accelerates the aging process in the brain and thus the risk for age‐related disorders such as dementia.
Perfect Maps and Relatively Discrete Collections
Authors: BURKE DENNIS K. , HANSELL ROGER W.
Published: December 2006

We show that the image of a s̀‐relatively discrete cover of a space under a perfect map has a s̀‐relatively discrete refinement. From this we deduce that spaces with a s̀‐relatively discrete network and, in particular, s̀‐relatively discrete sets, are invariant under perfect maps. Another corollary is that weakly s̀‐refinable spaces are preserved by perfect maps, a result previously shown by the first author.
Algebraic Properties of the Uniform Closure of Spaces of Continuous Functions
Authors: GARRIDO I. , MONTALVO F.
Published: December 2006

For a completely regular space X, C(X) denotes the algebra of all real‐valued and continuous functions over X. This paper deals with the problem of knowing when the uniform closure of certain subsets of C(X) has certain algebraic properties. In this context we give an internal condition, “property A,” to characterize the linear subspaces whose uniform closure is an inverse‐closed subring of C(X).
Dendrons, Dendritic Spaces, and Uniquely Arcwise Connected Spaces
Authors: NIKIEL J.
Published: December 2006

The paper summarizes recent developments concerning natural orderings and order topologies on uniquely arcwise connected spaces among which dendrons and R‐trees are given special attention.
Extending Invariant Measures on Topological Groupsa
Authors: ZAKRZEWSKI PIOTR
Published: December 2006

Let G be an uncountable Hausdorff topological group. We prove that if G is either Polish and not locally compact or compact and not zero‐dimensional, or the countable product of finite groups with uniformly bounded cardinalities, then every invariant s̀‐finite measure on G has a proper invariant extension. We do this by expressing G as the union of a “short” chain of its proper subgroups.
Increased Sensitivity to Oxidative Stress and the Loss of Muscarinic Receptor Responsiveness in Senescence
Authors: JOSEPH J. A. , VILLALOBOS‐MOLINA R. , DENISOVA N. , ERAT S. , JIMENEZ N. , STRAIN J.
Published: December 2006

SUMMARY
Free Intracellular Calcium in Aging and Alzheimer's Disease
Authors: MÜLLER WALTER E. , HARTMANN HENRIKE , ECKERT ANNE , VELBINGER KARSTEN , FöRSTL HANS
Published: December 2006

SUMMARY AND FINAL CONCLUSION
Manifestations of Power and Visual Culture: Some Examples in Extremaduran Mudejar Architecture
Authors: Mogollón Cano-Cortés M. Pilar
Published: December 2006

This essay treats mudejar architecture in the Spanish region of Extremadura as an expression of coexistence, convergence, and conflict between Christian and Islamic societies. Specifically, it centers on two Extremaduran churches, Santa María in Badajoz and Nuestra Señora de la Concepción in Hornachos, each borne out of a different historical and political situation. These two cases demonstrate that initially the use of Islamic elements in Christian buildings served to reflect the power of the monarchy and of the victorious society on the built environment, but that over time those same forms became an integral part of Christian culture.