bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rainfall partitioning into throughfall, stemflow, and interception within a single beech (Fagus sylvatica L.) canopy: influence of foliation, rain event characteristics, and meteorology
Authors: Staelens Jeroen , De Schrijver An , Verheyen Kris , Verhoest Niko E. C. 
Published: May 2007

AbstractWhile the hydrological balance of forest ecosystems has often been studied at the annual level, quantitative studies on the factors determining rainfall partitioning of individual rain events are less frequently reported. Therefore, the effect of the seasonal variation in canopy cover on rainfall partitioning was studied for a mature deciduous beech (Fagus sylvatica L.) tree over a 2‐year period. At the annual level, throughfall amounted to 71% of precipitation, stemflow 8%, and interception 21%. Rainfall partitioning at the event level depended strongly on the amount of rainfall and differed significantly (p < 0·001) between the leafed and the leafless period of the year. Therefore, water fluxes of individual events were described using a multiple regression analysis (ra2 > 0·85, n = 205) with foliation, rainfall characteristics and meteorological variables as predictor variables. For a given amount of rainfall, foliation significantly increased interception and decreased throughfall and stemflow amounts. In addition, rainfall duration, maximum rainfall rate, vapour pressure deficit, and wind speed significantly affected rainfall partitioning at the event level. Increasing maximum hourly rainfall rate increased throughfall and decreased stemflow generation, while higher hourly vapour pressure deficit decreased event throughfall and stemflow amounts. Wind speed decreased throughfall in the growing period only. Since foliation and the event rainfall amount largely determined interception loss, the observed net water input under the deciduous canopy was sensitive to the temporal distribution of rainfall. Copyright © 2007 John Wiley & Sons, Ltd.
Unexpected paracrine action of prostate cancer cells harboring a new class of androgen receptor mutation—A new paradigm for cooperation among prostate tumor cells
Authors: Lapouge Gaëlle , Erdmann Eva , Marcias Gemma , Jagla Monika , Monge Audrey , Kessler Pascal , Serra Sebastian , Lang Hervé , Jacqmin Didier , Bergerat Jean‐Pierre , Céraline Jocelyn 
Published: May 2007

AbstractThe emergence of mutations in the androgen receptor (AR) gene is a recurrent event during progression of prostate cancer (PCa) on androgen ablation therapy. In this study, we show that nonsense mutations that lead to carboxyl‐terminal end truncated ARs are found at high frequency in metastatic PCas. Transcriptional activities of the Q640X mutant AR in the androgen‐sensitive LNCaP cell line differ to those of the wild‐type AR. Indeed, this mutant AR exhibits strong and ligand‐independent transcriptional activities from an artificial promoter construct containing two repeats of androgen‐responsive elements, but is inactive on the human PSA gene promoter. Nevertheless, the expression of the Q640X mutant AR in LNCaP cells is accompanied by an increase in the level of PSA protein, and by an increase in the expression of the endogenous AR gene. This enhanced expression of the endogenous AR gene is not limited to the sole transfected cells, but is observed in non‐transfected neighboring cells. Additionally, in co‐cultures of transfected and non‐transfected LNCaP cells, the Q640X mutant AR leads to an unpredicted nuclear localization of the endogenous AR protein in the two cellular populations and this, in the absence of androgen. These data indicate that cells expressing the Q640X mutant AR acquire the property to emit a signal that activates the AR in neighboring cells by a paracrine mechanism and in a ligand‐independent manner. Our data strongly support the notion of cooperation among tumor cells in PCa and could be of relevance for the understanding of progression on androgen ablation therapy. © 2007 Wiley‐Liss, Inc.
Carbaryl exposure and incident cancer in the Agricultural Health Study
Authors: Mahajan Rajeev , Blair Aaron , Coble Joseph , Lynch Charles F. , Hoppin Jane A. , Sandler Dale P. , Alavanja Michael C.R. 
Published: May 2007

AbstractCarbaryl is a carbamate insecticide with a broad spectrum of uses in agricultural, commercial and household settings. It has previously been linked with non‐Hodgkin lymphoma (NHL) but studies of cancer risk in humans are limited. We examined occupational carbaryl use and risk of all cancers in the Agricultural Health Study, a prospective study of a cohort of pesticide applicators in North Carolina and Iowa. This analysis included 21,416 subjects (1,291 cases) enrolled from 1993–1997 and followed for cancer incidence through 2003. Pesticide exposure and other data were collected using self‐administered questionnaires. Poisson regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs) while controlling for potential confounders. Carbaryl was not associated with cancer risk overall. Relative to subjects who never used carbaryl, melanoma risk was elevated with >175 lifetime exposure‐days (RR = 4.11; 95%CI, 1.33–12.75; p‐trend = 0.07), >10 years of use (RR = 3.19; 95%CI, 1.28–7.92; p‐trend = 0.04), or ≥10 days of use per year (RR = 5.50; 95%CI, 2.19–13.84; p‐trend < 0.001). Risk remained after adjusting for sunlight exposure. Although not significant, there appeared to be a trend of decreasing prostate cancer risk with increasing level of exposure. A small increase in NHL risk was observed using some, but not all, exposure measures. No associations were observed with other examined cancer sites. Because the observed results were not hypothesized a priori and because of limited study of their biological plausibility, they should be interpreted with caution. © 2007 Wiley‐Liss, Inc.
Adenovirus‐mediated small hairpin RNA targeting Bcl‐XL as therapy for colon cancer
Authors: Zhu Hongbo , Zhu Yuping , Hu Jingzi , Hu Wenxian , Liao Yongqiang , Zhang Jun , Wang Da , Huang Xuefeng , Fang Bingliang , He Chao 
Published: May 2007

AbstractBcl‐XL, an anti‐apoptotic protein of Bcl‐2 family, is overexpressed in colon cancers. To determine Bcl‐XL's potential feasibility as a therapeutic target, we constructed a recombinant adenovirus that expressed a U6 promoter‐driven small hairpin RNA (shRNA) targeting Bcl‐XL (Ad/Bcl‐XL shRNA) and evaluated the vector's ability to induce RNA interference in vivo and alter apoptosis induction in colon cancer cells and tumours. Ad/Bcl‐XL shRNA effectively knocked down Bcl‐XL expression in colon cancer cells and decreased their viability. Treatment with Ad/Bcl‐XL shRNA but not control vectors led to dramatically increased cleavage of cellular apoptosis‐related enzymes caspase‐9, caspase‐3 and poly(ADP‐ribose) polymerase. Ad/Bcl‐XL shRNA also significantly suppressed the growth of subcutaneous tumours derived from DLD1 cells in a nude mouse model and did so without causing any obvious damage to normal tissues or normal human fibroblasts. Together, our results support the feasibility of using adenovirus‐mediated RNA interference therapy targeting Bcl‐XL against colon cancers and warrant further studies of its safety and efficacy. © 2007 Wiley‐Liss, Inc.
Tandem enzyme‐catalysed reduction/ cis‐dihydroxylation of 2,2,2‐trifluoroace‐ tophenone: chemoenzymatic routes to new enantiopure phenol and benzylic alcohol reagents
Authors: Boyd Derek R. , Sharma Narain D. , Ljubez Vera , Malone John F. , Allen Christopher C. R. 
Published: May 2007

AbstractFactors that control the competition between toluene dioxgenase‐catalysed arene cis‐dihydroxylation and dehydrogenase‐catalysed ketone reduction have been studied, using whole cells of Pseudomonas putida UV and three alkylaryl ketones. The triol metabolite, obtained from 2,2,2‐trifluoroacetophenone, has been used in the synthesis of single enantiomer chiral phenols and benzylic alcohols. Potential applications of the methylether derivatives of the chiral phenols and benzylic alcohols, as resolving agents, have been found. Copyright © 2007 Society of Chemical Industry
Optimized production and concentration of lentiviral vectors containing large inserts
Authors: Yacoub Nadya al , Romanowska Malgorzata , Haritonova Natalie , Foerster John 
Published: May 2007

AbstractGeneration of high titer lentiviral stocks and efficient virus concentration are central to maximize the utility of lentiviral technology. Here we evaluate published protocols for lentivirus production on a range of transfer vectors differing in size (7.5–13.2 kb). We present a modified virus production protocol robustly yielding useful titers (up to 107/ml) for a range of different transfer vectors containing packaging inserts up to 7.5 kb. Moreover, we find that virus recovery after concentration by ultracentrifugation depends on the size of the packaged inserts, heavily decreasing for large packaged inserts. We describe a fast (4 h) centrifugation protocol at reduced speed allowing high virus recovery even for large and fragile lentivirus vectors. The protocols outlined in the current report should be useful for many labs interested in producing and concentrating high titer lentiviral stocks. Copyright © 2007 John Wiley & Sons, Ltd.
Optimization of short‐term transgene expression by sodium butyrate and ubiquitous chromatin opening elements (UCOEs)
Authors: de Poorter Jolanda J. , Lipinski Kai S. , Nelissen Rob G. H. H. , Huizinga Tom W. J. , Hoeben Rob C. 
Published: May 2007

AbstractBackgroundPredictable and adequate transgene expression is essential for clinical gene therapy. Several studies have focused on optimization of transgene expression. In this study the effect of sodium butyrate (NaB) and a ubiquitous chromatin opening element (UCOE) on short‐term gene expression after adenovirus‐mediated gene transfer in fibroblastic interface cells from periprosthetic tissue in loosened orthopedic implants is investigated.MethodsCultures of diploid human interface cells from four patients were infected with an adenovirus type‐5 vector that carries the luciferase gene driven by the cytomegalovirus (CMV) promoter as a reporter. In addition, viruses with a UCOE were evaluated. Twenty‐four hours after infection NaB was added in concentrations of 0 to 9 mM. Luciferase activity was tested after a further 24 h.ResultsNaB in a concentration of 6 mM caused a 7‐ to 16‐fold increase in reporter gene expression compared to control condition. There was no difference in reporter gene expression when cells were infected with Ad.1.5UCOE‐CMV.Luc compared to Ad.CMV.Luc. A combination of NaB and a UCOE had no advantage over NaB alone.ConclusionsAddition of NaB results in a marked increase in transgene expression in cultured cells. This would allow the enhancement of the expression of the transgene, without requiring a higher vector dose. Butyrate administration could not be substituted by inclusion of UCOEs in the vector. It remains to be established whether the effective concentrations of butyrate can be obtained in vivo. Copyright © 2007 John Wiley & Sons, Ltd.
Gene expression and internalization following vector adsorption to immobilized proteins: dependence on protein identity and density
Authors: Bengali Zain , C.Rea Jennifer , Shea Lonnie D. 
Published: May 2007

AbstractBackgroundGene delivery by non‐specific adsorption of non‐viral vectors to protein‐coated surfaces can reduce the amount of DNA required, and also increase transgene expression and the number of cells expressing the transgene. The protein on the surface mediates cell adhesion and vector immobilization, and functions to colocalize the two to enhance gene delivery. This report investigates the mechanism and specificity by which the protein coating enhances gene transfer, and determines if the protein coating targets the vector for internalization by a specific pathway.MethodsProteins (FBS, BSA, fibronectin, collagen I, and laminin) were dried onto culture dishes, followed by PEI/DNA complex adsorption for surface delivery. Reporter genes were employed to characterize transfection as a function of the protein identity and density. Vector immobilization was measured using radiolabeled plasmid, and internalization was quantified in the presence and absence of the endocytosis inhibitors chlorpromazine and genistein.ResultsFibronectin coating yielded the greatest expression for PEI/DNA polyplexes, with maximal expression at intermediate protein densities. Expression in control studies with bolus delivery was independent of the protein identity. Substrate binding was independent of the protein identity; however, internalization was greatest on surfaces coated with fibronectin and collagen I. Inhibition of caveolae‐mediated endocytosis reduced gene expression more than clathrin‐mediated endocytosis. Similarly, inhibition of caveolae‐mediated endocytosis significantly reduced the intracellular levels of DNA.ConclusionsFibronectin at intermediate densities mediated the highest levels of transgene expression, potentially by targeting internalization through caveolae‐mediated endocytosis. Substrate modifications, such as the identity and density of proteins, provide an opportunity for modification of biomaterials for enhancing gene expression. Copyright © 2007 John Wiley & Sons, Ltd.
On the distance matrix of a directed graph
Authors: Graham R. L. , Hoffman A. J. , Hosoya H. 
Published: May 2007

AbstractIn this note, we show how the determinant of the distance matrix D(G) of a weighted, directed graph G can be explicitly expressed in terms of the corresponding determinants for the (strong) blocks Gi of G. In particular, when cof D(G), the sum of the cofactors of D(G), does not vanish, we have the very attractive formulamagnified image.
Total matchings and total coverings of graphs
Authors: Alavi Y. , Behzad M. , Lesniak‐Foster L. M. , Nordhaus E. A. 
Published: May 2007

AbstractIn graph theory, the related problems of deciding when a set of vertices or a set of edges constitutes a maximum matching or a minimum covering have been extensively studied. In this paper we generalize these ideas by defining total matchings and total coverings, and show that these sets, whose elements in general consist of both vertices and edges, provide a way to unify these concepts. Parameters denoting the maximum and the minimum cardinality of these sets are introduced and upper and lower bounds depending only on the order of the graph are obtained for the number of elements in arbitrary total matchings and total coverings. Precise values of all the parameters are found for several general classes of graphs, and these are used to establish the sharpness of most of the bounds. In addition, variations of some well known equalities due to Gallai relating covering and matching numbers are obtained.
A digest of the four color theorem
Authors: Bernhart Frank R. 
Published: May 2007

AbstractA major event in 1976 was the announcement that the Four Color Conjecture (4CC) had at long last become the Four Color Theorem (4CT). The proof by W. Haken, K. Appel, and J. Koch is published in the Illinois Journal of Mathematics, and their two‐part article outlines the nature and reliability of the solution. The first section is a readable and informative historical survey. The reminder will appeal chiefly to specialists in graph theory. Although the logic of attack is relatively simple, the need to examine an immense number of individual cases is frustrating. Hopefully this first breakthrough will pave the way for a short elegant proof. For the second section, 1200 hours of computer time was required to verify the 4‐color reducibility of nearly 1900 configurations. At this time there is no good way to condense the proof. In this digest we offer an exposition of the main ideas. The first and the last parts are intended for a general audience, but the intermediate sections assume more knowledge of graph theory proper. The usual statement of the 4CC goes as follows: “All maps on the sphere or plane can be colored with four colors so that neighboring regions are never colored alike.” The form in which the 4CT was proved is “There exists an unavoidable set of reducible configurations, relative to triangulations of the plane.” The initial part of our task is to explain how the 4CC comes to be expressed in such jargon. The next step is to show how one finds simple finite sets of unavoidable configurations. Then comes the question of how to prove reducibility, followed by a consideration of the known obstacles to reduction. Our concluding remarks and criticisms include a consideration of prospects for the future.
Enumeration of graphs with signed points and lines
Authors: Harary Frank , Palmer Edgar M. , Robinson Robert W. , Schwenk Allen J. 
Published: May 2007

AbstractOur object is to enumerate graphs in which the points or lines or both are assigned positive or negative signs. We also treat several associated problems for which these configurations are self‐dual with respect to sign change. We find that the solutions to all of these counting problems can be expressed as special cases of one general formula involving the concatenation of the cycle index of the symmetric group with that of its pair group. This counting technique is based on Pólya's Enumeration Theorem and the Power Group Enumeration Theorem. Using a suitable computer program, we list the number of graphs of each type considered up to twelve points. Sharp asymptotic estimates are also obtained.
Wright's formulae for the number of connected sparsely edged graphs
Authors: Gray P. M. D. , Murray A. M. , Young N. A. 
Published: May 2007

AbstractWe have written computer programs to determine exactly the coefficients in Wright's formula for f(n, n + k), the number of connected sparsely edged labeled graphs (see preceding paper), and used them up to k = 24. We give the results up to k = 7.
A property of trees in terms of unique connected subgraphs
Authors: Hedetniemi Stephen T. , Spresser Diane M. 
Published: May 2007

AbstractThe following theorem is proved: Let G be a graph with p ≥ 3 points such that for some n, 3 ≤ n ≤ p, any n points lie on a unique smallest connected subgraph. Then G = Cn+1 or G is a tree, and conversely.
On the eulericity of a graph
Authors: Matthews K. R. 
Published: May 2007

AbstractThe eulericity ϵ(G) of a bridgeless graph G is defined as the least number of eulerian subgraphs of G which together cover the lines of G. A 1–1 correspondence is shown to exist between the k‐tuples of eulerian subgraphs of G and the proper flows (mod2k) on a given network based on G. The inequality ϵ(G) ⩽ 3 them follows from a result of Jaeger.
Matroidal families of finite connected nonhomeomorphic graphs exist
Authors: Andreae Thomas 
Published: May 2007

AbstractA matroidal family is a nonempty set ℱ of connected finite graphs such that for every arbitrary finite graph G the edge sets of the subgraphs of G which are isomorphic to an element of ℱ form a matroid on the edge set of G. In the present paper the question whether there are any matroidal families besides the four previously described by Simões‐Pereira is answered affirmatively. It is shown that for every natural number n ⩾ 2 there is a matroidal family that contains the complete graph with n vertices. For n = 4 this settles Simões‐Pereira's conjecture that there is a matroidal family containing all wheels.
Graph Decompositions Satisfying Extremal Degree Constraints
Authors: Catlin Paul A. 
Published: May 2007

AbstractWe show that the vertex set of any graph G with p⩾2 vertices can be partitioned into non‐empty sets V1, V2, such that the maximum degree of the induced subgraph 〈Vi〉 does not exceed

where pi = |Vi|, for i=1, 2. Furthermore, the structure of the induced subgraphs is investigated in the extreme case.
An infinite family of octahedral crossing numbers
Authors: Gross Jonathan L. 
Published: May 2007

AbstractThis paper calculates some crossing numbers for certain octahedral graphs. Precisely, if the number p is a prime power congruent to 1 modulo 4, then the crossing number of the p‐dimensional octahedral graph in the orientable surface of genus (p–1)(p‐4)/4 is (p2–p)/2. The key step is the construction of a self‐dual imbedding of the complete graph on p vertices such that no face boundary contains a repeated vertex.
Counterexamples to faudree and schelp's conjecture on hamiltonian‐connected graphs
Authors: Thomassen Carsten 
Published: May 2007

AbstractFaudree and Schelp conjectured that for any two vertices x, y in a Hamiltonian‐connected graph G and for any integer k, where n/2 ⩽ k ⩽ n − 1, G has a path of length k connecting x and y. However, we show in this paper that there are infinitely many exceptions to this conjecture and we comment on some problems on path length distribution raised by Faudree and Schelp.
Full 4‐colorings of 4‐regular maps
Authors: Berman Kenneth A. , Shank H. 
Published: May 2007

AbstractA full coloring of a planar map is a face coloring such that all the faces at ech vertex are colored differently. In this paper the planar 4‐regular maps which have a full 4‐coloring are characterized. This leads to a characterization of the planar maps (not necessarily 4‐valent) which have a coupled 4‐coloring.
Enumeration of graphs by degree sequence
Authors: Hanlon Phil 
Published: May 2007

AbstractThe degree sequence (d0, d1, …, dp‐1) of a graph G of order p is defined by dk = the number of points of G of degree k. Methods of Robinson are extended to produce a generating function F(x0, x1, x2, …) where the coefficient of x…x is the number of graphs of order p having degree sequence (d0, …, dp‐1).
Orthogonal latin square graphs
Authors: Lindner Charles C. , Mendelsohn E. , Mendelsohn N. S. , Wolk Barry 
Published: May 2007

AbstractAn orthogonal latin square graph (OLSG) is one in which the vertices are latin squares of the same order and on the same symbols, and two vertices are adjacent if and only if the latin squares are orthogonal. If G is an arbitrary finite graph, we say that G is realizable as an OLSG if there is an OLSG isomorphic to G. The spectrum of G [Spec(G)] is defined as the set of all integers n that there is a realization of G by latin squares of order n. The two basic theorems proved here are (1) every graph is realizable and (2) for any graph G, Spec G contains all but a finite set of integers. A number of examples are given that point to a number of wide open questions. An example of such a question is how to classify the graphs for which a given n lies in the spectrum.
On the number of hamiltonian cycles in a maximal planar graph
Authors: Hakimi S. L. , Schmeichel E. F. , Thomassen C. 
Published: May 2007

AbstractWe consider the problem of the minimum number of Hamiltonian cycles that could be present in a Hamiltonian maximal planar graph on p vertices. In particular, we construct a p‐vertex maximal planar graph containing exactly four Hamiltonian cycles for every p ≥ 12. We also prove that every 4‐connected maximal planar graph on p vertices contains at least p/(log2 p) Hamiltonian cycles.
Three‐regular subgraphs of four‐regular graphs
Authors: Chvátal V. , Fleischner H. , Sheehan J. , Thomassen C. 
Published: May 2007

AbstractBerge conjectured that every finite simple 4‐regular graph G contains a 3‐regular subgraph. We prove that this conjecture is true if the cyclic edge connectivity λc(G) of G is at least 10. Also we prove that if G is a smallest counterexample, then λc(G) is either 6 or 8.