bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of motoneuron morphology in three dimensions. II. Building complete neurons
Authors: Marks William B. , Burke Robert E.
Published: June 2007

By using dendrogram data from six adult cat alpha motoneurons, we have constructed computer simulations of these cells in three dimensions (3D) by “growing” their dendritic trees from stem branches that were oriented as in the original cells. Individual trees were simulated by using the algorithms and parameters discussed in the companion paper (Marks and Burke [2007] J. Comp. Neurol. 503:685–700). It was not possible to distinguish real from simulated motoneurons by visual inspection of 3D drawings. Simulated cells were compared quantitatively with their actual exemplars by using features that were measured in spherical shells at various radii centered on the soma. These included nearest neighbor distances (NNDs) between branches, the sizes and overlaps between the territories of individual dendrites measured as convex hulls (polygons that enclose all branches passing through a shell), and the sizes of circular zones that contained no branches. We also compared the 3D fractal dimensions and lacunarity (a measure of the 3D dispersion of branches) in actual cells and their simulations. The statistical properties of these quantitative measures were not significantly different, suggesting that the simulation algorithm was quite successful. However, there were three exceptions: 1) there were more NNDs at distances < 50 μm in simulated than in actual motoneurons; 2) average overlaps between the territories of different dendrites were almost twice as large in simulated compared with actual motoneurons; and 3) estimates of lacunarity were also larger in simulated cells. These exceptions suggest that dendritic branches in actual motoneurons tend to avoid one another. We discuss possible interpretations of these results. J. Comp. Neurol. 503:701–716, 2007. Published 2007 Wiley‐Liss, Inc.
Real‐time fluorescence detection of multiple microscale cell culture analog devices in situ
Authors: Oh Taek‐il , Sung Jong Hwan , Tatosian Daniel A. , Shuler Michael L. , Kim Donghyun
Published: June 2007

Background:

We investigated multiple microscale cell culture analog (μCCA) assays in situ with a high‐throughput imaging system that provides quantitative, nondestructive, and real‐time data on cell viability. Since samples do not move between measurements, captured images allow accurate time‐course measurements of cell population response and tracking the fate of each cell type on a quantitative basis. The optical system was evaluated by measuring the short‐term response to ethanol exposure and long‐term growth of drug‐resistant tumor cell lines with simultaneous samples.

Methods:

The optical system based on epi‐fluorescent excitation consists of an LED and a CCD as well as discrete optical components for imaging a large number of cells simultaneously. HepG2/C3A and MESSA cell lines were cultured in two μCCA systems for continuous cell status monitoring in cell death experiments with ethanol and long‐term cell growth.

Results:

The experiment that tested ethanol uptake showed that ethanol immediately caused cell death. The system was applied to extracting dynamic constants in the uptake process. In the long‐term cell growth experiment, growth of MESSA cells was followed by a stationary phase and eventual cell death attributed to nutrient and oxygen depletion and a change in the pH because of the accumulation of wastes by cell metabolism. HepG2/C3A cells were subject to contact inhibition and cell number did not change significantly over time. Issues related to long‐term assays are also discussed.

Conclusions:

The quantitative results have been consistent with qualitative images and confirm the applicability of the portable optical system, and potential application to high‐throughput analysis of cell‐based assays to measure long‐term dynamics. © 2007 International Society for Analytical Cytology
Analysis of plasma protein adsorption onto PEGylated nanoparticles by complementary methods: 2‐DE, CE and Protein Lab‐on‐chip® system
Authors: Kim Hyun Ryoung , Andrieux Karine , Delomenie Claudine , Chacun Héléne , Appel Martine , Desmaële Didier , Taran Fréderic , Georgin Dominique , Couvreur Patrick , Taverna Myriam
Published: June 2007

The biodistribution of colloidal carriers after their administration in vivo depends on the adsorption of some plasma proteins and apolipoproteins on their surface. Poly(methoxypolyethyleneglycol cyanoacrylate‐co‐hexadecylcyanoacrylate) (PEG‐PHDCA) nanoparticles have demonstrated their capacity to cross the blood–brain barrier (BBB) by a mechanism of endocytosis. In order to clarify this mechanism at the molecular level, proteins and especially apolipoproteins adsorbed at the surface of PEG‐PHDCA nanoparticles were analyzed by complementary methods such as CE and Protein Lab‐on‐chip® in comparison with 2‐D PAGE as a method of reference. Thus, the ability of those methodologies to identify and quantify human and rat plasma protein adsorption onto PEG‐PHDCA nanoparticles and conventional PHDCA nanoparticles was evaluated. The lower adsorption of proteins onto PEG‐PHDCA nanoparticles comparatively to PHDCA nanoparticles was evidenced by 2‐D PAGE and Protein Lab‐on‐chip® methods. CE allowed the quantification of adsorbed proteins without the requirement of a desorption procedure but failed, in this context, to analyze complex mixtures of proteins. The Protein Lab‐on‐chip® method appeared to be very useful to follow the kinetic of protein adsorption from serum onto nanoparticles; it was complementary to 2‐D PAGE which allowed the identification (with a relative quantification) of the adsorbed proteins. The overall results suggest the implication of the apolipoprotein E in the mechanism of passage of PEG‐PHDCA nanoparticles through the BBB.
The Biflow: An instrument for transfer‐loop mediated, continuous, preparative‐scale isoelectric trapping separations
Authors: Shave Evan , Vigh Gyula
Published: June 2007

The Biflow, a new isoelectric trapping instrument was designed to obtain a narrow ΔpI fraction from a complex feed in one step. The Biflow contains two identical separation units, each unit houses: an anode and cathode compartment, an anodic and cathodic membrane, an anodic and cathodic separation compartment, and a separation membrane. The separation units are connected to independent power supplies. The anodic membranes in Units 1 and 2 typically buffer at the same pH value and so do the cathodic membranes. The separation membranes in Units 1 and 2 buffer at different pH values, these determine the pI range (ΔpI) of the product. The cathodic separation compartments in Units 1 and 2 contain the feed and harvest streams. The two anodic separation compartments, connected through an electrically insulating air gap, form the transfer loop through which the transfer stream is recirculated between Units 1 and 2. Ampholytic components in the feed, with pI values lower than the pH of the buffering membrane in Unit 1, pass into the transfer stream and are shuttled into Unit 2. In Unit 2, components in the transfer stream which have pI values higher than the pH of the buffering membrane in Unit 2, pass into the harvest stream. This double transfer of the target component, oppositely directed, guarantees the complete exclusion of products outside the desired ΔpI range from the harvest stream. The utility of the Biflow unit was demonstrated by isolating carnosine from a mixture of UV‐absorbing ampholytes and ovalbumin isoforms as well as 4.4 <pI <4.5 and 5.4 <pI <5.5 minor constituents from chicken egg white.
Repeatability of chemical cytometry: 2‐DE analysis of single RAW 264.7 macrophage cells
Authors: Sobhani Kimia , Fink Susan L. , Cookson Brad T. , Dovichi Norman J.
Published: June 2007

This report presents the use of 2‐DE with ultrasensitive fluorescence detection as a chemical cytometry tool to characterize the protein and biogenic amine content of single cells from the RAW 264.7 murine macrophage cell line. Cells were sorted by cell cycle prior to 2‐DE analysis. Cells in the G2/M phase of the cell cycle were aspirated into the first‐dimensional capillary and lysed. The cellular contents were fluorescently labeled and first separated by capillary sieving electrophoresis (CSE). Over 380 fractions were transferred from the first‐dimensional capillary to the second‐dimensional capillary, where components were further separated by MEKC and detected by laser‐induced fluorescence. Twenty‐five spots common to the four electropherograms were fit with a 2‐D Gaussian surface to determine spot position, width, and amplitude. The RSD in CSE mobility was 1.0 ± 0.6%. The mean uncertainty in spot position was 1.3 times larger than the mean spot width in the CSE dimension. The average SD in MEKC migration time was 0.37 ± 0.13 s, which is smaller than the average spot size in this dimension. Spot capacity was 200. The RSD in spot amplitude was 50%, reflecting a large cell‐to‐cell variation in component expression.
Spatiotemporal analyses of interactions between entorhinal and CA1 projections to the subiculum in rat brain slices
Authors: Cappaert Natalie L.M. , Wadman Wytse J. , Witter Menno P.
Published: June 2007

The subiculum and the entorhinal cortex (EC) are important structures in processing and transmitting information between the neocortex and the hippocampus. The subiculum potentially receives information from the EC through two routes. In addition to a direct projection from EC to the subiculum, there is an indirect polysynaptic connection. The latter uses a number of possible pathways, which all converge onto the final projection from the hippocampal field CA1 to the subiculum. In this series of experiments we investigated to what extent activity in both pathways influences population activity of subicular neurons. We used voltage sensitive dyes in combined hippocampal‐EC slices of the rat to measure the spatio‐temporal activity patterns. To activate the two inputs to the subiculum, stimulation electrodes were placed in the stratum oriens/alveus of CA1 and in layer III of the medial EC. The response patterns evoked in the subiculum after electrical stimulation of each of these input pathways separately were compared with the response patterns after simultaneous stimulation of both areas (medial EC + CA1). A comparison of the computed added responses of the two individual stimulations with the measured responses after simultaneous stimulation suggests that both inputs are linearly added in the subiculum with very little nonlinear interactions. This strongly suggests that in the subiculum interaction at a single cell level of the direct and the indirect pathways from the EC is an unlikely scenario. © 2007 Wiley‐Liss, Inc.
Metal oxide coated cell culture arrays for rapid biological screening
Authors: Jarrell John D. , Eun Tai H. , Samale Marcus , Briant Clyde , Sheldon Brian W. , Morgan Jeffrey R.
Published: June 2007

The biointerface of metallic alloy implants is a spontaneously formed metal oxide layer. This study presents a novel method for creating titanium oxide xerogel coated microplates for high‐throughput biological screening that overcomes several limitations of using bulk metal samples to study oxides. Metal–organic precursors were used to evaluate the influence of Al, V, Ca, and P doped smooth and textured titanium oxide xerogel coatings on the bioresponse of human fibroblasts to increase understanding of the soft tissue sealing around transepithelial devices. Coatings made of titanium n‐butoxide were characteristically smooth, while those of titanium isopropoxide were micro‐ and nanofeatured. Screening consisted of WST‐1 proliferation assay, calcein AM cell number and viability assay, and a modified cell seeding efficiency and centrifugation adhesion assay. Small variations in initial attachment and centrifugation adhesion of human fibroblasts were observed among the coatings and comparable to tissue‐culture treated polystyrene. Proliferation and viability at 24 and 48 h were reduced by the 10 and 20% vanadium additions. Metal oxide coated microplates are adaptable to the investigation of a wide range of metal–organic derived chemistries and the influence of oxide texture, and level of oxide crystallinity and oxide grain size on the biological responses of cells. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Ring inversion in 1,4,7 cyclononatriene and analogues: Ab initio and DFT calculations and topological analysis
Authors: Zamora Miguel A. , Suvire Fernando D. , Enriz Ricardo D.
Published: June 2007

The multidimensional conformational potential energy hypersurfaces (PEHSs) for cis‐cis‐cis 1,4,7 cyclononatriene (I), Tribenzocyclononatriene (TBCN) (II), and cis‐cis‐cis cyclic triglycine (III) were comprehensively investigated at the Hartree–Fock (HF/6‐31G(d)) and density functional theory (B3LYP/6‐31G(d,p)) levels of theory. The equilibrium structures, their relative stability, and the transition state (TS) structures involved in the conformational interconversion pathways were analyzed. Altogether, four geometries (two low‐energy conformations and two transition states) were found to be important for a description of the conformational features of compounds I–III. B3LYP/aug‐cc‐pvdz//B3lYP/6‐31G(d,p) and MP2/6‐31G(d,p)//B3LYP/6‐31G(d,p) single point calculations predict that the conformational interconversion between crown and twist forms requires 14.01, 26.71, and 17.79 kcal/mol for compounds I, II, and III, respectively, which is in agreement with the available experimental data. A topological study of the conformational PEHSs of compounds I–III was performed. Our results allow us to form a concise idea about the internal intricacies of the PEHSs of compounds I–III, describing the conformations as well as the conformational interconversion process in these hypersurfaces. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Radiofrequency radiation (900 MHz) induces Egr‐1 gene expression and affects cell‐cycle control in human neuroblastoma cells
Authors: Buttiglione M. , Roca L. , Montemurno E. , Vitiello F. , Capozzi V. , Cibelli G.
Published: June 2007

Many environmental signals, including ionizing radiation and UV rays, induce activation of Egr‐1 gene, thus affecting cell growth and apoptosis. The paucity and the controversial knowledge about the effect of electromagnetic fields (EMF) exposure of nerve cells prompted us to investigate the bioeffects of radiofrequency (RF) radiation on SH‐SY5Y neuroblastoma cells. The effect of a modulated RF field of 900 MHz, generated by a wire patch cell (WPC) antenna exposure system on Egr‐1 gene expression, was studied as a function of time. Short‐term exposures induced a transient increase in Egr‐1 mRNA level paralleled with activation of the MAPK subtypes ERK1/2 and SAPK/JNK. The effects of RF radiations on cell growth rate and apoptosis were also studied. Exposure to RF radiation had an anti‐proliferative activity in SH‐SY5Y cells with a significant effect observed at 24 h. RF radiation impaired cell cycle progression, reaching a significant G2‐M arrest. In addition, the appearance of the sub‐G1 peak, a hallmark of apoptosis, was highlighted after a 24‐h exposure, together with a significant decrease in mRNA levels of Bcl‐2 and survivin genes, both interfering with signaling between G2‐M arrest and apoptosis. Our results provide evidence that exposure to a 900 MHz‐modulated RF radiation affect both Egr‐1 gene expression and cell regulatory functions, involving apoptosis inhibitors like Bcl‐2 and survivin, thus providing important insights into a potentially broad mechanism for controlling in vitro cell viability. J. Cell. Physiol. 213:759–767. © 2007 Wiley‐Liss, Inc.
Matching cutsets in graphs
Authors: Moshi Augustine M.
Published: June 2007

Let G = (V,E) be an undirected graph. A subset F of E is a matching cutset of G if no two edges of F are incident with the same point, and G‐F has more components than G. Chv́atal [2] proved that it is NP‐complete to recognize graphs with a matching cutset even if the input is restricted to graphs with maximum degree 4. We prove the following: (a) Every connected graph with maximum degree ⩽3 and on more than 7 points has a matching cutset. (In particular, there are precisely two connected cubic graphs without a matching cutset). (b) Line graphs with a matching cutset can be recognized in O(|E|) time. (c) Graphs without a chordless circuit of length 5 or more that have a matching cutset can be recognized in O(|V||E|3) time.
A note concerning graphs with unique f‐factors
Authors: Jackson Bill , Whitty R. W.
Published: June 2007

We show that if a 2‐edge connected graph G has a unique f‐factor F, then some vertex has the same degree in F as in G. This conclusion is the best possible, even if the hypothesis is considerably strengthened.
The 2‐hamiltonian cubes of graphs
Authors: Koh K. M. , Teo K. L.
Published: June 2007

This paper deals with the problem of characterizing the pairs of vertices x,y in a connected graph G such that G3 ‐ {x,y} is hamiltonian, where G3 is the cube of G. It is known that the cube G3 is 2‐hamiltonian if G is 2‐connected. In this paper, we first prove the stronger result that G3 ‐ {x,y} is hamiltonian if either x or y is not a cut‐vertex of G, and then proceed to characterize those cut‐vertices x and y of G such that G3 ‐{x,y} is hamiltonian. As a simple consequence of these, we obtain Schaar's characterization of a connected graph G such that G3 is 2‐hamiltonian.
Domination in graphs with minimum degree two
Authors: McCuaig William , Shepherd Bruce
Published: June 2007

The domination number γ(G) of a graph G = (V, E) is the minimum cardinality of a subset of V such that every vertex is either in the set or is adjacent to some vertex in the set. We show that if a connected graph G has minimum degree two and is not one of seven exceptional graphs, then γ(G)γ 2/5|V|. We also characterize those connected graphs with γ(G)γ 2/5|V|.
The ally‐reconstruction number of a tree with five or more vertices is three
Authors: Myrvold Wendy
Published: June 2007

The ally‐reconstruction number of a graph G, ally‐rn(G), is the minimum number of vertex‐deleted subgraphs required in order to identify G up to isomorphism. In this paper, we show that ally‐rn(T) = 3 for any tree T with five or more vertices.
A note on bipartite subgraphs of triangle‐free regular graphs
Authors: Locke S. C.
Published: June 2007

Lower bounds on the size of a maximum bipartite subgraph of a triangle‐free r‐regular graph are presented.
Hamiltonian properties of domination‐critical graphs
Authors: Wojcicka Ewa
Published: June 2007

In this paper we show that every connected, 3‐γ‐critical graph on more than 6 vertices has a Hamiltonian path.
Class 1 conditions depending on the minimum degree and the number of vertices of maximum degree
Authors: Niessen Thomas , Volkmann Lutz
Published: June 2007

A graph is called Class 1 if the chromatic index equals the maximum degree. We prove sufficient conditions for simple graphs to be Class 1. Using these conditions we improve results on some edge‐coloring theorems of Chetwynd and Hilton. We also improve a theorem concerning the 1‐factorization of regular graphs of high degree.
Diameters of iterated clique graphs of chordal graphs
Authors: Chen Bor‐Liang , Lih Ko‐Wei
Published: June 2007

The clique graph K(G) of a graph is the intersection graph of maximal cliques of G. The iterated clique graph Kn(G) is inductively defined as K(Kn−1(G)) and K1(G) = K(G). Let the diameter diam(G) be the greatest distance between all pairs of vertices of G. We show that diam(Kn(G)) = diam(G) — n if G is a connected chordal graph and n ≤ diam(G). This generalizes a similar result for time graphs by Bruce Hedman.
Vertex signatures and edge‐4‐colorings of 4‐regular plane graphs
Authors: Jaeger François , Koester Gerhard
Published: June 2007

We associate partitions of the edge‐set of a 4‐regular plane graph into 1‐factors or 2‐factors to certain 3‐valued vertex signatures in the spirit of the work by H. Grötzsch [1]. As a corollary we obtain a simple proof of a result of F. Jaeger and H. Shank [2] on the edge‐4‐colorability of 4‐regular plane graphs made up by the superposition of 4 families of disjoint simple closed curves.
Lower bounds for lower Ramsey numbers
Authors: Faudree Ralph , Gould Ronald J. , Jacobson Michael S. , Lesniak Linda
Published: June 2007

For any graph G, let i(G) and μ;(G) denote the smallest number of vertices in a maximal independent set and maximal clique, respectively. For positive integers m and n, the lower Ramsey number s(m, n) is the largest integer p so that every graph of order p has i(G) ≤ m or μ;(G) ≤ n. In this paper we give several new lower bounds for s (m, n) as well as determine precisely the values s(1, n).
On the cycle‐isomorphism of graphs
Authors: Yu Xingxing
Published: June 2007

This paper considers conditions ensuring that cycle‐isomorphic graphs are isomorphic. Graphs of connectivity ⩾ 2 that have no loops were studied in [2] and [4]. Here we characterize all graphs G of connectivity 1 such that every graph that is cycle‐isomorphic to G is also isomorphic to G.
On the residue of a graph
Authors: Favaron O. , Mahéo M. , Saclé J.‐F.
Published: June 2007

The residue R of a simple graph G of degree sequence S: d1 ⩾ d2 ⩾ …︁ ⩾ dn is the number of zeros obtained by the iterative process consisting of deleting the first term d1 of S, subtracting 1 from the d1 following ones, and sorting down the new sequence. The depth is the number n ‐ R of steps in this algorithm. We prove here some conjectures given by the computer program GRAFFITI, in particular, magnified image.
On the homogeneous representation of interval graphs
Authors: Olariu Stephan
Published: June 2007

An interval graph G is homogeneously representable if for every vertex v of G there exists an interval representation of G with v corresponding to an end interval. We show that the homogeneous representation of interval graphs is rooted in a deeper property of a class of graphs that we characterize by forbidden configurations.
A characterization of domination perfect graphs
Authors: Zverovich I. E. , Zverovich V. E.
Published: June 2007

Let γ(G) and i(G) be the domination number and independent domination number of a graph G, respectively. Sumner and Moore [8] define a graph G to be domination perfect if γ(H) = i(H), for every induced subgraph H of G. In this article, we give a finite forbidden induced subgraph characterization of domination perfect graphs.

Bollobás and Cockayne [4] proved an inequality relating γ(G) and i(G) for the class of K1,k ‐free graphs. It is shown that the same inequality holds for a wider class of graphs.
Seven criteria for integer sequences being graphic
Authors: Sierksma Gerard , Hoogeveen Han
Published: June 2007

Seven criteria for integer sequences being graphic are listed. Being graphic means that there is a simple graph with the given integer sequence as degree sequence. One of the criteria leads to a new and constructive proof of the well‐known criterion of Erdös‐Gallai.
[a,b]‐factorizations of graphs
Authors: Mao‐Cheng Cai
Published: June 2007

Let a and b be integers with b ⩾ a ⩾ 0. A graph G is called an [a,b]‐graph if a ⩽ dG(v) ⩽ b for each vertex v ∈ V(G), and an [a,b]‐factor of a graph G is a spanning [a,b]‐subgraph of G. A graph is [a,b]‐factorable if its edges can be decomposed into [a,b]‐factors. The purpose of this paper is to prove the following three theorems: (i) if 1 ⩽ b ⩽ 2a, every [(12a + 2)m + 2an,(12b + 4)m + 2bn]‐graph is [2a, 2b + 1]‐factorable; (ii) if b ⩽ 2a −1, every [(12a −4)m + 2an, (12b −2)m + 2bn]‐graph is [2a −1,2b]‐factorable; and (iii) if b ⩽ 2a −1, every [(6a −2)m + 2an, (6b + 2)m + 2bn]‐graph is [2a −1,2b + 1]‐factorable, where m and n are nonnegative integers. They generalize some [a,b]‐factorization results of Akiyama and Kano [3], Kano [6], and Era [5].
On an upper bound for the harmonious chromatic number of a graph
Authors: Lu Zhikang
Published: June 2007

The upper bound for the harmonious chromatic number of a graph that has been given by Sin‐Min Lee and John Mitchem is improved.
Characterization of a class of triangle‐free graphs with a certain adjacency property
Authors: Alspach Brian , Chen C. C. , Heinrich Katherine
Published: June 2007

Let m and n be nonnegative integers. Denote by P(m,n) the set of all triangle‐free graphs G such that for any independent m‐subset M and any n‐subset N of V(G) with M ∩ N = Ø, there exists a unique vertex of G that is adjacent to each vertex in M and nonadjacent to any vertex in N. We prove that if m ⩾ 2 and n ⩾ 1, then P(m,n) = Ø whenever m ⩽ n, and P(m,n) = {Km,n+1} whenever m > n. We also have P(1,1) = {C5} and P(1,n) = Ø for n ⩾ 2. In the degenerate cases, the class P(0,n) is completely determined, whereas the class P(m,0), which is most interesting, being rich in graphs, is partially determined.
On the orientable genus of graphs embedded in the klein bottle
Authors: Robertson Neil , Thomas Robin
Published: June 2007

Let G be a graph embedded in the Klein bottle with “representativity” at least four. We give a formula for the orientable genus of G, which also implies a polynomially bounded algorithm. The formula is in terms of the number of times certain closed curves on the Klein bottle intersect the graph. In particular, it shows that a cut‐and‐paste technique for re‐embedding graphs is the best possible.
The prism‐free planar graphs and their cycles bases
Authors: Hartvigsen David , Mardon Russell
Published: June 2007

Dirac (1962) showed that the planar graphs with no prism minor are the graphs obtainable by 2‐sums from bonds, cycles, wheels and K5\e's. We give a new characterization of these graphs in terms of an optimization problem defined on the cycle bases of a graph.
On zero‐sum delta‐systems and multiple copies of hypergraphs
Authors: Caro Yair
Published: June 2007

We prove the following generalization of earlier results of Bialostocki and Dierker [3] and Caro [7].

Theorem. Let t ⩾ k ⩾ 2 be positive integers such that k | t, and let c :E(K) → ℤk be a mapping of all the r‐subsets of an rt + k −1 element set into the cyclic group of order k; then there are t pairwise disjoint r‐subsets e1, e2, …, et such that Σ c(ei) = 0. This theorem is further generalized to Δ‐systems. An application of this theorem and extension of the proof technique are combined to establish the currently best estimates of the zero‐sum Ramsey numbers R(tG, ℤt).
Upper bounds for harmonious colorings
Authors: McDiarmid Colin , Xinhua Luo
Published: June 2007

A harmonious coloring of a simple graph G is a coloring of the vertices such that adjacent vertices receive distinct colors and each pair of colors appears together on at most one edge. The harmonious chromatic number h(G) is the least number of colors in such a coloring. We improve an upper bound on h(G) due to Lee and Mitchem, and give upper bounds for related quantities.
The number of shortest cycles and the chromatic uniqueness of a graph
Authors: Teo C. P. , Koh K. M.
Published: June 2007

For a graph G, let g(G) and σg(G) denote, respectively, the girth of G and the number of cycles of length g(G) in G. In this paper, we first obtain an upper bound for σg(G) and determine the structure of a 2‐connected graph G when σg(G) attains the bound. These extremal graphs are then more‐or‐less classified, but one case leads to an unsolved problem. The structural results are finally applied to show that certain families of graphs are chromatically unique.
Ramsey problems and their connection to tuŕan‐type extremal problems
Authors: Faudree Ralph J. , Simonovits Miklós
Published: June 2007

We shall investigate the behavior of the Ramsey function r(L, Tn), where L is a fixed graph and Tn is a tree on n vertices, while n ← ∞. We prove that in this case the appropriate Ramsey problem can be reduced to a corresponding Turán type extremal problem: if we take a maximum N for which a KN can be colored in two colors so that the first color contains no L and the second color contains no Tn, then by the results of Erdös, Faudree, Rousseau and Schelp, N = (p ‐ 1)n + 0(n), where p is the chromatic number of L. We shall prove that in the corresponding Ramsey‐coloring the edges of the first color from an “almost Turán graph” on p ‐ 1 classes. We shall also describe how the finer structure of L influences this Ramsey number and the stability of the Ramsey coloring. The most important new results—compared with some earlier results—are that we can guarantee structural properties of the extremal colorings.
The value of the Ramsey number r(3, 8)
Authors: McKay Brendan D. , Min Zhang Ke
Published: June 2007

The Ramsey number R(3, 8) can be defined as the least number n such that every graph on n vertices contains either a triangle or an independent set of size 8. With the help of a substantial amount of computation, we prove that R(3, 8)=28.
Hamiltonian graphs involving distances
Authors: Chen Guantao , Schelp R. H.
Published: June 2007

Let G be a graph of order n. We show that if G is a 2‐connected graph and max{d(u), d(v)} + |N(u) U N(v)| ≥ n for each pair of vertices u, v at distance two, then either G is hamiltonian or G 3Kn/3 U T1 U T2, where n  O (mod 3), and T1 and T2 are the edge sets of two vertex disjoint triangles containing exactly one vertex from each Kn/3. This result generalizes both Fan's and Lindquester's results as well as several others.
A degree condition for the existence of k‐factors
Authors: Nishimura Tsuyoshi
Published: June 2007

Let k be an integer such that ≦, and let G be a connected graph of order n with ≦, kn even, and minimum degree at least k. We prove that if G satisfies max(deg(u), deg(v)) ≦ n/2 for each pair of nonadjacent vertices u, v in G, then G has a k‐factor.
Alternating hamiltonian cycles in two colored complete bipartite graphs
Authors: Chetwynd A. G. , Hilton A. J. W.
Published: June 2007

We give necessary and sufficient conditions for the existence of an alternating Hamiltonian cycle in a complete bipartite graph whose edge set is colored with two colors.
The chromatic index of complete multipartite graphs
Authors: Hoffman D. G. , Rodger C. A.
Published: June 2007

We show that a complete multipartite graph is class one if and only if it is not eoverfull, thus determining its chromatic index.
On the number of list‐colorings
Authors: Donner Quentin
Published: June 2007

Given a list of boxes L for a graph G (each vertex is assigned a finite set of colors that we call a box), we denote by f(G, L) the number of L‐colorings of G (each vertex must be colored wiht a color of its box). In the case where all the boxes are identical and of size k, f(G, L) = p(G, k), where P=G, k) is the chromatic polynominal of G.

We denote by F(G, k) the minimum of f(G, L) over all the lists of boxes such that each box has size at least k. It is clear that F(G, k) ≤ P(G, k) for all G, k, and we will see in the introduction some examples of graphs such that F(G, k) < P(G, k) for some k. However, we will show, in answer to a problem proposed by A. Kostochka and A. Sidorenko (Fourth Czechoslovak Symposium on Combinatorics, Prachatice, Jin, 1990), that for all G, F(G, k) = P(G, k) for all k sufficiently large. It will follow in particular that F(G, k) is not given by a polynominal in k for all G. The proof is based on the analysis of an algorithm for computing f(G, L) analogous to the classical one for computing P(G, k).
On the minimum size of tight hypergraphs
Authors: Arocha Jorge L. , Bracho Javier , Neumann‐Lara Victor
Published: June 2007

A k‐graph, H = (V, E), is tight if for every surjective mapping f: V → {1,….k} there exists an edge α ϵ E sicj tjat f|α is injective. Clearly, 2‐graphs are tight if and only if they are connected. Bounds for the minimum number ϕ of edges in a tight k‐graph with n vertices are given. We conjecture that ϕ for every n and prove the equality when 2n + 1 is prime. From the examples, minimal embeddings of complete graphs into surfaces follow. © 1992 John Wiley & Sons, Inc.
Complete subgraphs with large degree sums
Authors: Faudree Ralph J.
Published: June 2007

Let t(n, k) denote the Turán number—the maximum number of edges in a graph on n vertices that does not contain a complete graph Kk+1. It is shown that if G is a graph on n vertices with n ≥ k2(k – 1)/4 and m < t(n, k) edges, then G contains a complete subgraph Kk such that the sum of the degrees of the vertices is at least 2km/n. This result is sharp in an asymptotic sense in that the sum of the degrees of the vertices of Kk is not in general larger, and if the number of edges in G is at most t(n, k) – ϵ (for an appropriate ϵ), then the conclusion is not in general true. © 1992 John Wiley & Sons, Inc.
Vertex 2‐isomorphism
Authors: Swaminathan R. , Wagner Donald K.
Published: June 2007

Whitney's theorem on 2‐isomorphism characterizes the set of graphs having the same cycles as a given graph, where a cycle is regarded as a set of edges. In this paper, vertex 2‐isomorphism is defined and used to prove a vertex analogue of Whitney's theorem. The main theorem states that two connected graphs have the same set of cycles, where a cycle is now regarded as a set of vertices, if and only if one can be obtained from the other by a sequence of simple operations. © 1992 John Wiley & Sons, Inc.
On three zero‐sum Ramsey‐type problems
Authors: Alon Noga , Caro Yair
Published: June 2007

For a graph G whose number of edges is divisible by k, let R(G,Zk) denote the minimum integer r such that for every function f: E(Kr) ↦ Zk there is a copy G1 of G in Kr so that Σe∈E(G1) f(e) = 0 (in Zk). We prove that for every integer k1 R(Kn, Zk) ≤ n + O(k3 log k) provided n is sufficiently large as a function of k and k divides (). If, in addition, k is an odd prime‐power then R(Kn, Zk) ≤ n + 2k ‐ 2 and this is tight if k is a prime that divides n. A related result is obtained for hypergraphs. It is further shown that for every graph G on n vertices with an even number of edges R(G,Z2) ≤ n + 2. This estimate is sharp. © 1993 John Wiley & Sons, Inc.
Recombinant DNA in meat additives: Specific detection of Roundup Ready™ soybean by nested PCR
Authors: Brod Fábio CA , Arisi Ana CM
Published: June 2007

Soybean proteins are widely used by the meat industry as technological coadjutor when producing processed products such as emulsified and ground meat products. Since regulations for the use and labeling of GMOs and derived ingredients are in force in Brazil, a PCR‐based method capable of detecting Roundup Ready™ (RR) soybean was employed for meat additives. Thirty‐two samples of meat additives containing soy proteins were tested for the presence of soybean amplifiable DNA and RR soybean DNA. Twenty‐five samples gave a positive signal for the lectin gene, confirming the presence of soybean amplifiable DNA and 15 samples returned a positive signal for specific RR detection confirming the presence of genetically modified soy. These results demonstrate for the first time the presence of RR soybean in meat additives. This method may be useful for meat industries interested in controlling the presence of RR soybean in additives used for meat products manufacture. Copyright © 2007 Society of Chemical Industry
Lubricant additives effects on the hydrodynamic lubrication of misaligned conical–cylindrical bearings
Authors: Elsharkawy Abdallah A.
Published: June 2007

Conical–cylindrical bearings are used in electrohydraulic servo systems to improve the control accuracy, eliminate the static friction and increase the normal load‐carrying capacity. A non‐Newtonian rheological model to investigate theoretically the effects of lubricant additives on the performance of misaligned conical–cylindrical bearings is proposed in this study. In this model, the non‐Newtonian behaviour resulting from blending the lubricant with polymer additives is simulated by Stokes couple stress fluid model. The formed boundary layer at the bearing surface is described through the use of a hypothetical porous medium layer that adheres to the bearing surface. The Brinkman‐extended Darcy equations are utilised to model the flow in the porous region. A stress jump boundary condition is applied at the porous media/fluid film interface. The misalignment of the cylinder rod is also considered. A modified form of the Reynolds equation is derived and solved numerically using a finite difference scheme. The effects of bearing geometry and non‐Newtonian behaviour of the lubricant on the steady‐state performance characteristics such as pressure distribution, load‐carrying capacity and coefficient of friction are presented and discussed. The results showed that lubricant additives significantly increase the load‐carrying capacity and reduce the coefficient of friction as compared to the Newtonian lubricants. Furthermore, the misalignment of the piston rod has significant effects on the performance of conical–cylindrical bearings. Copyright © 2007 John Wiley & Sons, Ltd.
The heirs of the councils of defense
Authors: Pollock Willits
Published: June 2007

The War Emergency Bodies are fast being demobilized, their programs abandoned, their trained and volunteer workers going back to other pursuits. Who will take up their burden?
Nassau county plans a new government
Authors: Fleischer John
Published: June 2007

To modernize a county government involves in almost every state the dexterous avoidance of constitutional obstacles, but Nassau county on Long Island, New York, nevertheless, presents a finished plan that provides a chief executive, a shortened ballot and sound financial organization.
How the recall worked in Charlotte
Authors: Shannonhouse F. M.
Published: June 2007

The literature of the recall is slender because this instrument is rarely utilized. In Charlotte, North Carolina, it was recently tested under ideally difficult conditions.
Good seed and deep plowing
Authors: Dawson Edgar
Published: June 2007

It is Prof. Dawson's conviction that much of modern political reform principle is so solidly established that it may properly be made part of primary, high and normal school instruction in civics as it already is in the colleges. He is giving his entire time in 1920 to initiating this movement.
The second proportional representation election in kalamazoo
Authors: Hatton Augustus R.
Published: June 2007

Kalamazoo (population 50,000) has a close copy of the National Municipal League's model charter and as it is the largest American city electing its council by proportional representation, the story of its second election is important evidence.
A city for sale
Authors: Kitchen Victor C.
Published: June 2007

Strange spectacles have followed in the wake of war and not the least of these is the sight of an entire city of 35,000 popoulation, Nitro, West Virginia, offered for sale to the highest bidder.
Proportional representation in boulder, colorado
Authors: Lien Arnold J.
Published: June 2007

Boulder has had two elections under proportional representation. Its experience is here related.
The nebraska constitutional convention
Authors: Senning John P.
Published: June 2007

“The mountain was in labor, and Jove was afraid; but it brought forth a mouse.” … You may think this a too pessimistic view, but the author has given the facts from which to judge.
Philadelphia's new council
Authors: Gruenberg F. P.
Published: June 2007

The new, single chamber body shows creditable improvement over the old bicameral system.
City manager movement: progress of manager plan in one hundred eighty‐five cities
Authors: Otis Harrison Gray
Published: June 2007

Being the sixth installment of short stories compiled by the secretary of the City Manager's Association. The next will be “Reports from Managers in the Prairie States.”
A review of city planning in the United States, 1919–1920
Authors: Kimball Theodora
Published: June 2007

It has been the long‐time policy of the REVIEW to publish an annual report of city planning progress in the United States. The 1917–1918 and 1918–1919 REVIEWS were also prepared by Miss Kimball.
The pennsylvania commission on constitutional amendment
Authors: Lewis Burnham E.
Published: June 2007

When the legislature authorized a constitutwnal commission instead of a convention many Pennsylvanians feared it was a scheme for delay. To their surprise the commission has proved a most useful body
Nashville's experience with commission government
Authors: Hudson Irby Roland
Published: June 2007

Nashville's commission government, designed to perpetuate a group in power, is marked for destruction.
Country planning and national forests
Authors: Greeley W. B.
Published: June 2007

How shall we plan to secure highest returns from our forests in timber, agriculture, health and recreation? It is a nation's job.
Fundamental objections to the walsh bill
Authors: Olmsted Frederick Law
Published: June 2007

The Walsh bill permits the Yellowstone river to be dammed three miles below Lake Yellowstone in favor of private interests. I t is a menace to Yellowstone park, as will appear from the following statement made before the Senate Committee on Irrigation.
Where to begin in town improvement
Authors: James Harlean
Published: June 2007

If your town is dead, you can't sell it a park program or a city plan right off the bat. What it needs is a new civic conscience. Begin with garden committee.
Civil service and the police
Authors: Marsh H. W.
Published: June 2007

The secretary of the Civil Service Reform League takes issue with Mr. Fosdick, author of American Police Systems, regarding the place of civil service examinations in police administration.
Ohio legislature denies relief to insolvent cities
Authors: Thomas William M.
Published: June 2007

The Smith law bends but docs not break. Property classijication was defeated so income tax was not pushed.
The assault on the st. louis machine
Authors: Budenz Louis F.
Published: June 2007

St. Louis is no longer “unashamed.” Valiant eforts have been made to throw 08 machine rule with little success as yet, but with prmisefor thefuture. Mayor Kiel was almost defeated.
Deadlock in public utility regulation: II. Nothing ever settled
Authors: Bauer John
Published: June 2007

The second article in our series on the regulation of public utilities. What are fair value, a reasonable return, proper operating costs? These and other questions are still unsolved.
Cleveland revolts
Authors: Maxey Chester Collins
Published: June 2007

As all the world knows, Cleveland on last election day adopted the city‐manager plan with proportional representation to go into effect two years hence.
Advanced police methods in Berkeley
Authors: Schutt Harold G.
Published: June 2007

High‐grade policemen, one‐third, of them college graduates, plus an appropriate utilization of their brains, have made Berkeley's police force famous and their chief the president of the Association of Chiefs of POlice.
The recent spolis raid in washington
Authors: Marsh H. W.
Published: June 2007

“When we see a lot of framed timbers, different portions of which we know to have been gotten out at different times and places by different workmen, Stephen, Franklin, Rogre and James, for instance, and we see all these timbers joined together and see that they exactly make the frame of a house … we find it impossible not to believe that Stephen and Franklin and Roger and James all understood one another from the beginning.”—Abraham Lincoln.
John Stuart Mill and the model city Charter
Authors: Anderson William
Published: June 2007

Mill, writing more than a generation before our Committee on a Municipal Program reported the Model Charter, advanced the same principles which we now advocate.
High water and power development proposed in California
Authors: Locke Wm. J.
Published: June 2007

This measure was voted on at the November election. Early returns received as we go to press indicate that it was defeated by 3 to 1.
High spots in the report of our committee on civil service. Presented at the philadelphia meeting
Authors: Dennison Henry S.
Published: June 2007

The full report has been referred to the Council with power and will be published if they so authorize. The editor will be glad to have your comments for the guidance of the Council.
Chicago's old first ward. A case study in politicl behavior
Authors: Lasswell Harold D.
Published: June 2007

We have all heard of “Bathhouse” Coughlin and “Hinky Dink” Kenna and theycan be duplicated in any large city. But what about their constituencies? What are their hopes and fears and politics? And why?
The National Municipal League in retrospect and prospect
Authors: Woodruff Clinton Rogers
Published: June 2007

Address before the Annual Dinner of the National Municipal League, Wednesday, November 22, 1922.
Milwaukee registers progress
Authors: Hoan Daniel W.
Published: June 2007

Mayor Hoan believes that the city renders service to the people at a fraction of what privat einterests would require to do the work. We welcome stories of progress from other cities
Our legislative mills III. wisconsin
Authors: Thompson Walter
Published: June 2007

A keen study of a legislature which has led the way in many reforms of procedure but now suffers for lack of party organization and leadership. Nathing has yet appeared to fill the place of the old–fashioned boss
The initiative and referndum in thirty–six american cities iin the years 1921 and 1922
Authors: Shoup E. L.
Published: June 2007

A review of the initiative and referendum in cities with full statistical tables
An experiment in new methods of selecting policemen
Authors: Martin Edward M.
Published: June 2007

A recent study, conducted in Newark, N. J., of the application of mental tests to the selection of policemen rendered very encouraging results. The method is here descrived for the general reader. Believing that everyone is interested in this subject we have devoted more than our usual space to it
The national conference on the science of politics
Authors: Hall Arnold Bennett
Published: June 2007

The first national conference devoted exclusively to the development of a scientific method in Political Science
Commentary upon the comparative tax rates of 177 cities, 1923
Authors: Rightor C. E.
Published: June 2007

One year ago (December, 1922) the “Review” published a tabulation of the 1922 tax rates of 32 cities in the United States and Canada, giving the rates in detail by purpose and the total rate adjusted upon a uniform basis for comparison. This year, the Detroit Bureau of Governmental Research, in collecting and tabulating the 1923 tax rates, has expanded the list ot include 165 cities of the United States and 12 cities of Canada having in excess of 30,000 population
Candidate antigens specifically detected by cerebrospinal fluid‐IgG in oligoclonal IgG bands‐positive multiple sclerosis patients
Authors: Nakamura Masashi , Kuramasu Atsuo , Nakashima Ichiro , Fujihara Kazuo , Itoyama Yasuto
Published: June 2007

The aim of the present study was to detect antigenic proteins that react specifically with cerebrospinal fluid (CSF)‐IgG from oligoclonal IgG bands (OB)‐positive multiple sclerosis (MS) patients. To identify such antigenic proteins, we developed a rat brain proteome map using 2‐DE and applied it to the immunoscreening of brain proteins that react with CSF‐IgG but not with serum‐IgG in OB‐positive MS patients. After sequential MALDI‐TOF mass spectrometry, eight proteins [two neuronal proteins (tubulin β‐2 and γ enolase‐2), HSP‐1, Tpi‐1 protein and cellular enzymes (creatine kinase, phosphopyruvate hydratase, triosephosphate isomerase and phosphoglycerate kinase‐1)] were identified as candidate antigens in seven MS patients. Reactivity to tubulin was seen in Western blotting in four patients, and CSF‐specific anti‐tubulin IgG was detected in one patient. In addition, CSF‐specific anti‐gamma enolase IgG was found in another patient. These findings suggest that intrathecal immune responses may occur against a broad range of proteins in MS.
Recommended management of sleep problems in childhood
Authors: Tomlin Stephen , Gringras Paul
Published: June 2007

Our series Prescribing in children gives practical advice for the successful management of childhood problems in general practice. Here the authors describe sleep problems encountered in children and discuss the available treatments. Copyright © 2007 Wiley Interface Ltd