bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing Platinum Azido Complexes by 14N and 15N NMR Spectroscopy
Authors: Farrer Nicola J. , Gierth Peter , Sadler Peter J.
Published: September 2011

Metal azido complexes are of general interest due to their high energetic properties, and platinum azido complexes in particular because of their potential as photoactivatable anticancer prodrugs. However, azido ligands are difficult to probe by NMR spectroscopy due to the quadrupolar nature of 14N and the lack of scalar 1H coupling to enhance the sensitivity of the less abundant 15N by using polarisation transfer. In this work, we report 14N and 15N NMR spectroscopic studies of cis,trans,cis‐[Pt(N3)2(OH)2(NH3)] (1) and trans,trans,trans‐[Pt(N3)2(OH)2(X)(Y)], where X=Y=NH3 (2); X=NH3, Y=py (3) (py=pyridine); X=Y=py (4); and selected PtII precursors. These studies provide the first 15N NMR data for azido groups in coordination complexes. We discuss one‐ and three‐bond J(15N,195Pt) couplings for azido and am(m)ine ligands. The 14Nα (coordinated azido nitrogen) signal in the PtIV azido complexes is extremely broad (W1/2≈2124 Hz for 4) in comparison to other metal azido complexes, attributable to a highly asymmetrical electric field gradient at the 14Nα atom. Through the use of anti‐ringing pulse sequences, the 14N NMR spectra, which show resolution of the broad 14Nα peak, were obtained rapidly (e.g., 1.5 h for 10 mM 4). The linewidths of the 14Nα signals correlate with the viscosity of the solvent. For 15N‐enriched samples, it is possible to detect azido 15N resonances directly, which will allow photoreactions to be followed by 1D 15N NMR spectroscopy. The T1 relaxation times for 3 and 4 were in the range 5.7–120 s for 15N, and 0.9–11.3 ms for 14N. Analysis of the 1J(15N,195Pt) coupling constants suggests that an azido ligand has a moderately strong trans influence in octahedral PtIV complexes, within the series 2‐pic<py<NH3<Cl−<N3−<NO2−<SCN− (2‐pic=2‐methylpyridine). In addition, an axial Cl− appears to weaken an equatorial PtIVNH3 bond to a greater extent than an axial OH− ligand.
Evaluation of Carcinogenic Risk Due to Accidental Ingestion of PAHs in Contaminated Soils
Authors: Gitipour Saeid , Mohebi Mina , Taheri Ehsan
Published: September 2011

Polycyclic aromatic hydrocarbons (PAHs) are types of hazardous contaminants, which their ingestion could cause severe consequences on human health. Leakages from storage tanks, underground pipelines, and evaporation ponds are the main sources of soil and groundwater contaminations at the Tehran Oil Refinery area (TOR site), located in south of Tehran, Iran. In this study, soil samples were collected from different locations at and adjacent to a polluted stream in the south of the refinery. The samples were analyzed for two hazardous PAH compounds, namely benzo[a]anthracene and acenaphthene. The clean up levels due to the accidental ingestion of contaminated soils at the site were also investigated in accordance to the U.S.EPA guidelines. Comparing the soil analysis results indicated that the benzo[a]anthracene concentrations in the samples varied from 53 to 299 mg/kg, which were higher than the clean up level of 1.17 mg/kg. Thus, soil remediation is required for this contaminant. The acenaphthene analysis results denoted that the average concentration of this contaminant was below the clean up level of 116.67 mg/kg, indicating that no treatment for this contaminant is necessary at the TOR site. Also, because the slope of the ground extends to the south of the stream, which stimulates the migration of the contaminants in this direction due to advection and dispersion mechanisms, the average of benzo[a]anthracene concentrations in south samples was higher than north samples (i.e., Cavg(S) = 160 ppm, Cavg(N) = 113 ppm). Various treatment techniques such as thermal desorption, soil vapor extraction (SVE), and solidification/stabilization (S/S) were investigated for this site. Due to moderate to high plasticity and relatively low permeability of the soil and low volatility of benzo[a]anthracene, however S/S method is recommended as a practical approach for the remediation of the soil at the site.
Bioremediation of Tannery Effluents Using a Consortium of Blue–Green Algal Species
Authors: Shashirekha Viswanaathan , Sridharan Melatheru Ramanujam , Swamy Mahadeswara
Published: September 2011

Trivalent chromium in the form of basic chromium sulfate (BCS) is used for tanning hides/skins and is a strong pollutant of the soil and water bodies. Significant quantities of unutilized chemicals, such as sulfates, chlorides, are also discharged, contributing to high levels of total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), etc. Though many treatment techniques are being practiced, biotechnological methods are gaining importance. Biosorption is recognized as a cost‐effective technology worldwide; one potential sorbent being blue–green algae (BGA), for treating metal‐bearing effluents. This work studies the feasibility of using a species each of Spirulina, Oscillatoria, and Synechocystis, individually and as a consortium, as sorbents to remove Cr3+ from a segregated stream, viz. exhaust chrome liquor (ECL) and synthetic BCS solution. The species studied were found to be effective in removing Cr3+ considerably at varying concentrations, besides reducing sulfates, BOD, COD, etc. The results of ECL experiments were more encouraging than those for BCS solution. The kinetic data on Cr3+ sorption onto algal biomass fit well into the pseudo‐second order model. The equilibrium data were analyzed using the classic Langmuir and Freundlich isotherm models, yielding good fits. The results of the experiments indicate that algal consortia could be good alternatives to the conventional treatment methods for leather and other industrial wastewaters containing chromium.
Facile morphology‐controlled hydrothermal synthesis of flower‐like self‐organized ZnO architectures
Authors: Zhang Rongxian , Yang Xiaofei , Zhang Du , Qin Jieling , Lu Chunyu , Ding Heyi , Yan Xuehua , Tang Hua , Wang Mingsong , Zhang Qi
Published: September 2011

Flower‐like self‐organized crystalline ZnO architectures were obtained through a facile and controlled hydrothermal process. As‐synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), electron diffraction and UV‐Vis spectroscopy. XRD and electron diffraction results confirmed the obtained materials are pure wurtzite ZnO. The effects of different ratios of starting materials and solvent on the morphologies of ZnO hydrothermal products were also evaluated by SEM observations. It is suggested that the use of water, rather than ethanol as the solvent, as well as employing a precursor of Zn(Ac)2 and 2NaOH (v/v) in hydrothermal reactions are responsible for the generation of specific flower‐like self‐assembled ZnO structures. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction of enterovirus infection and cow's milk‐based formula nutrition in type 1 diabetes‐associated autoimmunity
Authors: Lempainen J. , Tauriainen S. , Vaarala O. , Mäkelä M. , Honkanen H. , Marttila J. , Veijola R. , Simell O , Hyöty H. , Knip M. , Ilonen J.
Published: September 2011

Background

Enteral virus infections and early introduction of cow's milk (CM)‐based formula are among the suggested triggers of type 1 diabetes (T1D)‐associated autoimmunity, although studies on their role have remained contradictory. Here, we aimed to analyse whether interactions between these factors might clarify the controversies.

Materials

The study population comprised 107 subjects developing positivity for at least two T1D‐associated autoantibodies and 446 control subjects from the Finnish diabetes prediction and prevention cohort. Enterovirus, rotavirus, adenovirus, respiratory syncytial virus and bovine insulin‐binding antibodies were analysed from prospective serum samples at 3–24 months of age. Data on infant cow's milk exposure were available for 472 subjects: 251 subjects were exposed to cow's milk before 3 months of age and 221 subjects later in infancy.

Results

Signs of an enterovirus infection by 12 months of age were associated with the appearance of autoimmunity among children who were exposed to cow's milk before 3 months of age. Cox regression analysis revealed a combined effect of enterovirus infection and early cow's milk exposure for the development of ICA and any of the biochemically defined autoantibodies (p = 0.001), of IAA (p = 0.002), GADA (p = 0.001) and IA‐2A (p = 0.013).

Conclusions

The effect of enterovirus infection on the appearance of T1D‐associated autoimmunity seems to be modified by exposure to cow's milk in early infancy suggesting an interaction between these factors. Moreover, these results provide an explanation for the controversial findings obtained when analysing the effect of any single one of these factors on the appearance of T1D‐associated autoimmunity. Copyright © 2011 John Wiley & Sons, Ltd.
Nonenzymatic glycation of high‐density lipoprotein impairs its anti‐inflammatory effects in innate immunity
Authors: Liu Donghui , Ji Liang , Zhang Dongmei , Tong Xunliang , Pan Bing , Liu Pinli , Zhang Youyi , Huang Yining , Su Jinzi , Willard Belinda , Zheng Lemin
Published: September 2011

Aims/hypothesis

In type 2 diabetes mellitus (T2DM), the abnormal protein and lipid composition of diabetic high‐density lipoprotein (HDL) could impair its anti‐inflammatory functions. Whether nonenzymatic glycation directly impaired the anti‐inflammatory effects of HDL in innate immunity remained unclear.

Methods

Human acute monocytic leukemia cell line (THP‐1) cells, mouse RAW 264.7 macrophages and primary human monocytes derived macrophages were pre‐incubated with native HDL, diabetic HDL isolated from T2DM patients or HDL glycated with different doses of d‐glucose in vitro and then challenged with lipopolysaccharide (LPS). The release of tumor necrosis factor (TNF)‐α and IL‐1β was assayed by enzyme‐linked immunosorbent assay (ELISA). Phosphorylation of Iκ‐Bα in cytoplasm and nuclear translocation of NF‐κB were detected by western blot. Glycation levels of native HDL, glycated HDL and diabetic HDL were determined using LC‐MS/MS.

Results

The potency of diabetic HDL to inhibit the release of TNF‐α (p < 0.05) and IL‐1β (p < 0.001) was dramatically attenuated compared with that of native HDL. Similarly, glycation of HDL in vitro impaired its ability to inhibit TNF‐α and IL‐1β release in a glucose dose‐dependent manner. Moreover, apoHDL still effectively inhibited the release of TNF‐α and IL‐1β induced by LPS, but glycated apoHDL partly lost such abilities. Nonenzymatic glycation levels of glycated HDL and diabetic HDL increased 28 fold (p < 0.001) and 4 fold (p < 0.001), respectively compared with that of native HDL.

Conclusions

In this study, we observed that diabetic HDL and HDL glycated in vitro both partly lose their protective effects to inhibit cytokines release induced by LPS in macrophages, and nonenzymatic glycation of the protein components of HDL plays key roles in these impairments. Copyright © 2011 John Wiley & Sons, Ltd.
Zinc Complexes of Piperazinyl‐Derived Aminephenolate Ligands: Synthesis, Characterization and Ring–Opening Polymerization Activity
Authors: Ikpo Nduka , Saunders Lisa N. , Walsh Jillian L. , Smith Jennifer M. B. , Dawe Louise N. , Kerton Francesca M.
Published: September 2011

A series of zinc complexes was prepared from 4,6‐disubstituted (R,R′) o‐[(4‐methyl‐1‐piperazinyl)methyl]phenols ([ONNR′,R]H) and characterized by elemental analysis, 1H and 13C{1H} NMR spectroscopy, and X‐ray crystallography. Reaction of these products with diethylzinc gave Zn[ONNtBu,tBu]2 (1) as a monometallic complex and {[μ‐ONNR′,R]ZnEt}2 [R′ = Me, R = tBu, (2); R′ = R = tBu (3); R′ = R = tAm (4)] bimetallic species that have distorted tetrahedral environments about the Zn centres. Reaction of 3 and 4 with alcohols gave {[ONNtAm,tAm]Zn(μ‐OR″)}2 [R″ = Bn (5); R″ = Et (6)] bimetallic species in which the Zn centres are bridged by benzyl alkoxide and ethoxide groups, respectively. A morpholinyl derived ligand was also synthesized and characterized (L4H), and its 1:1 stoichiometric reaction with ZnEt2 resulted in complex 7, {[μ‐ONOtBu,tBu]ZnEt}2. The reactivity of complexes 2–7 in the ring‐opening polymerization of rac‐lactide (LA) and ϵ‐caprolactone (ϵ‐CL) was studied. Reactions of carbon dioxide with cyclohexene oxide in the presence of 6 or 7/ROH (R = Bn, Et) afforded cyclohexene carbonate.
Control of the Coordination Geometry Around Platinum by a Supramolecular Capsule
Authors: Koblenz Tehila S. , Dekker Henk L. , de Koster Chris G. , van Leeuwen Piet W. N. M. , Reek Joost N. H.
Published: September 2011

The coordination geometry around a platinum atom can be controlled by a diphosphane capsule composed of a tetracationic xantphos‐type ligand and a tetraanionic calix[4]arene. Reaction of the diphosphane capsule with the platinum precursor [PtCl2(MeCN)2] yields the bisligated biscalix[4]arene trans‐platinum capsule, whereas the same diphosphane in the absence of calix[4]arene prefers the formation of the monoligated cis‐platinum complex, as indicated by 31P{1H} NMR and ESI‐MS. The two calix[4]arenes stabilize the kinetic product (trans‐Pt), and slow the formation of the thermodynamic product (cis‐Pt).
Integrated platform of capillary isoelectric focusing, trypsin immobilized enzyme microreactor and nanoreversed‐phase liquid chromatography with mass spectrometry for online protein profiling
Authors: Wang Tingting , Ma Junfeng , Wu Shuaibin , Yuan Huiming , Zhang Lihua , Liang Zhen , Zhang Yukui
Published: September 2011

An integrated platform with the combination of protein and peptide separation was established via online protein digestion, by which proteins were first separated by CIEF, online digested by a trypsin immobilized enzyme microreactor, trapped and desalted by two parallel trap columns, separated by nanoreversed‐phase and finally identified by MS. In such a platform, two hollow fiber membrane interfaces were used. One was applied to supply catholyte and electric contact, and another to supply adjustment buffer to improve the compatibility of protein separation and tryptic digestion. A poly(octadecyl acrylate‐co‐ethylene dimethacrylate) monolithic column served as the trap column to capture sample and to remove the ampholytes from CIEF. A hybrid silica monolith‐based immobilized trypsin microreactor was used for online protein digestion. To evaluate the performance of such a platform, a 4‐protein mixture with a loading amount of only 0.29 μg, was analyzed, and sequence coverages for BSA, myoglobin, β‐lactoglobulin and ribonuclease A were 8, 26, 10 and 54%, respectively. Furthermore, such an integrated platform was successfully applied for the analysis of proteins extracted from Escherichia coli, and 101 proteins were positively identified. We anticipate that the integrated platform developed herein will provide a promising tool for low‐abundance protein identification with the combination of top‐down and bottom‐up approaches.
Fast analysis of amino acids in wine by capillary electrophoresis with laser‐induced fluorescence detection
Authors: Mandrioli Roberto , Morganti Emanuele , Mercolini Laura , Kenndler Ernst , Raggi Maria A.
Published: September 2011

A fast analytical method has been developed for the determination of nine amino acids, together with serotonin, in wine samples of different origin and vintage. The method is based on capillary electrophoresis coupled to laser‐induced fluorescence detection. Separation was obtained by using a fused‐silica capillary (75 μm id, 74.0 cm total length, 60.0 cm length to detector) and a background electrolyte composed of carbonate buffer (20 mM, pH 9.2), applying a 20 kV voltage. Direct hydrodynamic injection of wine samples was made after an original microwave‐assisted derivatisation step with 5‐(4,6‐dichlorotriazinyl)aminofluorescein. Fluorescence was induced by an Ar‐Ion laser, exciting at 488 nm. Good linearity (r2>0.9990) was obtained for all considered analytes and sensitivity was also good, with limits of detection in the 7–50 ng/mL range. The method was successfully applied for the analysis of commercial Italian wines and thus seems to be suitable for the determination of the relevant amino acids and serotonin, providing good results in terms of accuracy and precision, together with the advantage of a very fast, microwave‐assisted derivatisation procedure. Future applications of the method are planned to check for wine adulterations and commercial frauds.
High‐speed separation of proteins by sodium dodecyl sulfate‐capillary gel electrophoresis with partial translational spontaneous sample injection
Authors: Lin Qing‐Hu , Cheng Yong‐Qiang , Dong Ya‐Ni , Zhu Ying , Pan Jian‐Zhang , Fang Qun
Published: September 2011

In this study, we developed a picoliter‐scale partial translational spontaneous injection approach which is suitable for high‐speed protein separation under sodium dodecyl sulfate‐capillary gel electrophoresis mode. On the basis of this approach, we built a high‐speed CE system for protein separation based on a short capillary and slotted‐vial array. The system has the advantages of simple structure, ease of building without the requirement of microfabricated devices, convenient operation, and low cost. Under the optimized conditions, picoliter‐scale sample plugs (corresponding to ∼65 μm plug length) were obtained, which ensured both the high speed and the high efficiency in protein separation. Five fluorescein isothiocyanate labeled proteins including myoglobin, egg albumin, bovine serum albumin, phosphorylase b, and myosin were separated within 60 s with an effective separation length of 1.5 cm. Theoretical plates per meter ranging from 2.58×105 to 1.28×106 (corresponding to 0.78–3.88 μm plate height) were obtained. The separation speed and separation efficiency of the present system are comparable to those of most microchip‐based capillary electrophoresis systems for protein separation. The relative standard deviations of the migration times were in the range of 0.9–1.3% (n=5). Good linear relationships between log relative molecular mass and migration time were obtained in the molecular weigh range of 17 200–500 000, which demonstrate the present system can be applied in protein relative molecular mass determination.
Seeing with the eyes shut: Neural basis of enhanced imagery following ayahuasca ingestion
Authors: de Araujo Draulio B. , Ribeiro Sidarta , Cecchi Guillermo A. , Carvalho Fabiana M. , Sanchez Tiago A. , Pinto Joel P. , de Martinis Bruno S. , Crippa Jose A. , Hallak Jaime E.C. , Santos Antonio C.
Published: September 2011

The hallucinogenic brew Ayahuasca, a rich source of serotonergic agonists and reuptake inhibitors, has been used for ages by Amazonian populations during religious ceremonies. Among all perceptual changes induced by Ayahuasca, the most remarkable are vivid “seeings.” During such seeings, users report potent imagery. Using functional magnetic resonance imaging during a closed‐eyes imagery task, we found that Ayahuasca produces a robust increase in the activation of several occipital, temporal, and frontal areas. In the primary visual area, the effect was comparable in magnitude to the activation levels of natural image with the eyes open. Importantly, this effect was specifically correlated with the occurrence of individual perceptual changes measured by psychiatric scales. The activity of cortical areas BA30 and BA37, known to be involved with episodic memory and the processing of contextual associations, was also potentiated by Ayahuasca intake during imagery. Finally, we detected a positive modulation by Ayahuasca of BA 10, a frontal area involved with intentional prospective imagination, working memory and the processing of information from internal sources. Therefore, our results indicate that Ayahuasca seeings stem from the activation of an extensive network generally involved with vision, memory, and intention. By boosting the intensity of recalled images to the same level of natural image, Ayahuasca lends a status of reality to inner experiences. It is therefore understandable why Ayahuasca was culturally selected over many centuries by rain forest shamans to facilitate mystical revelations of visual nature. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
NOS1 ex1f‐VNTR polymorphism affects prefrontal oxygenation during response inhibition tasks
Authors: Kopf Juliane , Schecklmann Martin , Hahn Tim , Dieler Alica C. , Herrmann Martin J. , Fallgatter Andreas J. , Reif Andreas
Published: September 2011

Impulsivity is a trait shared by many psychiatric disorders and therefore a suitable intermediate phenotype for their underlying biological mechanisms. One of the molecular determinants involved is the NOS1 ex1f‐VNTR, whose short variants are associated with a variety of impulsive behaviors. Fifty‐six healthy controls were stratified into homozygous long (LL) (30 probands) and short (SS) (26 probands) allele groups. Subjects completed a combined stop‐signal go/nogo task, while the oxygenation in the prefrontal cortex was measured with functional near‐infrared spectroscopy. Electromyography was recorded to control for differences in muscle activity in the two inhibition tasks. Two questionnaires on impulsive traits were completed. Differences between the two tasks are shown by distinct activation patterns within the prefrontal cortex. The nogo task resulted mainly in the activation of the dorsolateral prefrontal cortex (dlPFC), whereas successful and unsuccessful inhibition in the stop‐signal task elicited the predicted activity in the inferior frontal cortex (IFC). Although significant differences were found in neither the scores obtained on impulsivity‐related questionnaires nor the behavioral data, the LL group displayed increased dlPFC activity during nogo trials and the predicted activation in the IFC during successful inhibition in the stop‐signal task, while no significant activation was found in the SS group. Our data confirm an influence of NOS1 ex1f‐VNTR on impulsivity, as carriers of the short risk allele exhibited diminished activity of (pre‐)frontal brain regions during the inhibition in a stop‐signal task. Impairment of prefrontal control with consecutive failure of inhibitory processes might underlie association findings reported previously. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
N‐phosphinyl ureas: Synthesis, characterization, X‐ray structure, and in vitro evaluation of antitumor activity
Authors: Gholivand Khodayar , Dorosti Nilufar , Ghaziany Fatemeh , Mirshahi Manouchehr , Sarikhani Sina
Published: September 2011

A new series of N‐phosphinylureas 5b, 6a–7c was synthesized and characterized by 1H, 13C, 31P NMR, IR, and elemental analysis. The three‐dimensional structure of 5b has been determined by X‐ray crystallography. The crystal structure revealed the existence of four independent molecules. All structures form two chains with different arrangements and connect to each other via hydrogen bonds to produce two‐dimensional polymeric chains. The cytotoxicity of cyclophosphamide (a standard antitumor compound) and its nine analogues with formula R1C6H4 NHC(O)NHP(O)XCH2C(R2)2 CH2Y(X = Y = NH, R2 = CH3, R1 = H (5a), CH3 (5b), NO2 (5c), X = O, Y = NH, R2 = H, R1 = H (6a, CH3 (6b), NO2 (6c), and X = Y = O, R2 = CH3, R1 = H (7a), CH3 (7b), NO2 (7c)) as well as phenyl urea were evaluated in vitro against three human tumor cell lines K562, MDA‐MB‐231, and HepG2. The results showed that most of the compounds have significant activity against the selected cell lines. Also, HepG2 cells were more sensitive to all the tested compounds than other cell lines. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:74–83, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20754
Gerechte designs with rectangular regions
Authors: Courtiel J. , Vaughan E. R.
Published: September 2011

A gerechte framework is a partition of an n × n array into n regions of n cells each. A realization of a gerechte framework is a latin square of order n with the property that when its cells are partitioned by the framework, each region contains exactly one copy of each symbol. A gerechte design is a gerechte framework together with a realization.

We investigate gerechte frameworks where each region is a rectangle. It seems plausible that all such frameworks have realizations, and we present some progress toward answering this question. In particular, we show that for all positive integers s and t, any gerechte framework where each region is either an s × t rectangle or a t × s rectangle is realizable. © 2011 Wiley Periodicals, Inc. J Combin Designs 20:112‐123, 2012
Spanning Cycles Through Specified Edges in Bipartite Graphs
Authors: Zamani Reza , West Douglas B.
Published: September 2011

Pósa proved that if G is an n‐vertex graph in which any two nonadjacent vertices have degree‐sum at least n + k, then G has a spanning cycle containing any specified family of disjoint paths with a total of k edges. We consider the analogous problem for a bipartite graph G with n vertices and parts of equal size. Let F be a subgraph of G whose components are nontrivial paths. Let k be the number of edges in F, and let t1 and t2 be the numbers of components of F having odd and even length, respectively. We prove that G has a spanning cycle containing F if any two nonadjacent vertices in opposite partite sets have degree‐sum at least n/2 + τ(F), where τ(F) = ⌈k/2⌉ + ɛ (here ɛ = 1 if t1 = 0 or if (t1, t2)∈{(1, 0), (2, 0)}, and ɛ = 0 otherwise). We show also that this threshold on the degree‐sum is sharp when n>3k. © 2011 Wiley Periodicals, Inc. J Graph Theory 71:1–17, 2012
New Ore‐Type Conditions for H‐Linked Graphs
Authors: Ferrara Michael , Gould Ronald , Jacobson Michael , Pfender Florian , Powell Jeffrey , Whalen Thor
Published: September 2011

For a fixed (multi)graph H, a graph G is H‐linked if any injection f: V(H)→V(G) can be extended to an H‐subdivision in G. The notion of an H ‐linked graph encompasses several familiar graph classes, including k‐linked, k‐ordered and k‐connected graphs. In this article, we give two sharp Ore‐type degree sum conditions that assure a graph G is H ‐linked for arbitrary H. These results extend and refine several previous results on H ‐linked, k‐linked, and k‐ordered graphs. © 2011 Wiley Periodicals, Inc. J Graph Theory 71:69–77, 2012
Seymour's Second Neighborhood Conjecture for Tournaments Missing a Generalized Star
Authors: Ghazal Salman
Published: September 2011

Seymour's Second Neighborhood Conjecture asserts that every digraph (without digons) has a vertex whose first out‐neighborhood is at most as large as its second out‐neighborhood. We prove its weighted version for tournaments missing a generalized star. As a consequence the weighted version holds for tournaments missing a sun, star, or a complete graph. © 2011 Wiley Periodicals, Inc. J Graph Theory 71:89–94, 2012
Minors in large almost‐5‐connected non‐planar graphs
Authors: Kawarabayashi Ken‐Ichi , Maharry John
Published: September 2011

It is shown that every sufficiently large almost‐5‐connected non‐planar graph contains a minor isomorphic to an arbitrarily large graph from one of six families of graphs. The graphs in these families are also almost‐5‐connected, by which we mean that they are 4‐connected and all 4‐separations contain a “small” side.

As a corollary, every sufficiently large almost‐5‐connected non‐planar graph contains both a K3, 4‐minor and a ‐minor. The connectivity condition cannot be reduced to 4‐connectivity, as there are known infinite families of 4‐connected non‐planar graphs that do not contain a K3, 4‐minor. Similarly, there are known infinite families of 4‐connected non‐planar graphs that do not contain a ‐minor.
The A4‐structure of a graph
Authors: Barrus Michael D. , West Douglas B.
Published: September 2011

We define the A4‐structure of a graph G to be the 4‐uniform hypergraph on the vertex set of G whose edges are the vertex subsets inducing 2K2, C4, or P4. We show that perfection of a graph is determined by its A4‐structure. We relate the A4‐structure to the canonical decomposition of a graph as defined by Tyshkevich [Discrete Math 220 (2000) 201–238]; for example, a graph is indecomposable if and only if its A4‐structure is connected. We also characterize the graphs having the same A4‐structure as a split graph.
The structure of graphs with a vital linkage of order 2
Authors: Mayhew Dillon , Whittle Geoff , van Zwam Stefan H. M.
Published: September 2011

A linkage of order k of a graph G is a subgraph with k components, each of which is a path. A linkage is vital if it spans all vertices, and no other linkage connects the same pairs of end vertices. We give a characterization of the graphs with a vital linkage of order 2: they are certain minors of a family of highly structured graphs.
Comparison of four‐dimensional flow parameters for quantification of flow eccentricity in the ascending aorta
Authors: Sigovan Monica , Hope Michael D. , Dyverfeldt Petter , Saloner David
Published: September 2011

Purpose:

To compare quantitative parameters for assessing the degree of eccentric systolic blood flow in the ascending thoracic aorta (AsAo).

Materials and Methods:

Forty‐one patients were studied with three‐dimensional (3D), cine phase‐contract MRI (4D Flow). Analysis was performed at peak systole for a cross‐sectional plane in the AsAo just distal to the sinotubular junction. AsAo flow was graded as normal, mildly, or markedly eccentric based on qualitative visual assessment. For quantitative analysis, flow jet angle and normalized flow displacement from the vessel center were calculated.

Results:

Patients with normal AsAo systolic flow (n = 25) had an average flow jet angle of 13.7 degrees and flow displacement 0.04. These parameters were significantly elevated for patients with mild eccentric systolic flow (n = 6): 24.6 degrees (P = 0.012) and 0.12 (P = 0.001), respectively. However, for patients with marked eccentric flow (n = 10), only flow displacement was significantly elevated compared with the mild eccentric group (0.18; P = 0.04); flow angle was 25.7 degrees.

Conclusion:

Flow displacement is a more reliable quantitative parameter for measuring eccentric AsAo systolic flow than flow jet angle, and should be evaluated in studies investigating the role of eccentric flow in the promotion of aortic pathology. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
Comparison of matrix metalloproteinase activation after focal cortical ischemia in young adult and aged mice
Authors: Liguz‐Lecznar Monika , Ziemka‐Nalecz Malgorzata , Aleksy Monika , Kossut Malgorzata , Skangiel‐Kramska Jolanta , Nowicka Dorota
Published: September 2011

Matrix metalloproteinase (MMP) activity is implicated in the degradation of the extracellular matrix during cerebral ischemia. Although many studies have demonstrated spatiotemporal patterns of activation of gelatinases (MMP‐9 and MMP‐2) after ischemic stroke in young adult rodents, no data exist on MMP activity in old brains. In this study, we investigated the gelatinolytic activity in young adult (3‐month‐old) and aged (1‐year‐old) mice subjected to photothrombotic stroke. Using in situ zymography and gel zymography, we found that the basal gelatinolytic activity in the intact cerebral cortex was similar at both investigated ages. Similarly, after photothrombosis, the increased gelatinolytic response up to 7 days poststroke was the same in young and aged brains. At both ages, early activation of gelatinolysis in the ischemic core and the perilesional area was present in neuronal nuclei as revealed by colocalization of gelatinolytic product with NeuN immunostaining and DAPI. Additionally, application of specific antibodies against MMP‐9 and MMP‐2 revealed the increase in MMP‐9 immunoreactivity in cell nuclei as early as 4 hr poststroke. No differences between young and aged mice were observed concerning the level and localization of MMP‐9 immunoreactivity. The lack of age‐related differences in the degree and pattern of activation of gelatinolysis after focal stroke and the lack of correspondence between the results of in situ and gel zymography suggest that extracellular proteolysis is not directly responsible for the more severe outcome of ischemic stroke in aged subjects. © 2011 Wiley Periodicals, Inc.
Excitatory effect of histamine on rat spinal motoneurons by activation of both H1 and H2 receptors in vitro
Authors: Wu Guan‐Yi , Han Xiao‐Hu , Zhuang Qian‐Xing , Zhang Jun , Yung Wing‐Ho , Chan Ying‐Shing , Zhu Jing‐Ning , Wang Jian‐Jun
Published: September 2011

The central histaminergic nervous system, originating from the tuberomammillary nucleus of the hypothalamus, widely innervates almost the whole brain as well as the spinal cord. However, the effect of histamine on spinal motoneurons, the final common path for motor control, is still unknown. By using 8–14‐day‐old rat spinal slice preparations and intracellular recordings, the effect of histamine on motoneurons in lumbar spinal cord and the underlying mechanisms were studied. Bath application of histamine (30–300 μM) induced a membrane depolarization in the majority of recorded spinal motoneurons (78/90, 86%). Perfusing slices with tetrodotoxin or low‐Ca2+/high‐Mg2+ medium did not block the histamine‐induced excitation, indicating a direct postsynaptic action of histamine on motoneurons. Separate application of the selective histamine H1 receptor antagonist mepyramine or the selective histamine H2 receptor antagonist ranitidine partially suppressed the histamine‐induced excitation, whereas a combination of ranitidine and mepyramine totally blocked the excitatory effect of histamine on motoneurons. On the other hand, both the selective histamine H1 receptor agonist 2‐pyridylethylamine and the selective histamine H2 receptor agonist dimaprit mimicked the excitation of histamine on spinal motoneurons. These agonist‐induced excitations were also blocked by mepyramine or ranitidine. Furthermore, histamine affected membrane input resistance and potentiated repetitive firing behavior of spinal motoneurons. These results demonstrate that histamine excites rat spinal motoneurons via the histamine H1 and H2 receptors and increases their excitability, suggesting that the hypothalamospinal histaminergic fibers may directly modulate final motor outputs and actively regulate ongoing motor execution andspinal motor reflexes. © 2011 Wiley Periodicals, Inc.
Epigenetic control of somatostatin and cortistatin expression by β amyloid peptide
Authors: Rubio Alicia , Sánchez‐Mut José V. , García Esther , Velasquez Zahady D. , Oliver Jorge , Esteller Manel , Avila Jesús
Published: September 2011

β Amyloid, present in senile plaques, has been related largely to neuronal loss in the brain of patients with Alzheimer's disease. However, how neurons respond to β amyloid insults is still poorly understood. Here we show that β amyloid increases somatostatin and cortistatin gene expression mainly through an increase in histone 3 lysine 4 methylation (H3K4me3), a modification associated with transcriptional activation. Somatostatin and cortistatin partially decreased β amyloid toxicity in primary cortical neurons in culture. Thus we suggest that neurons respond to β amyloid insults by releasing somatostatin and cortistatin, which will act as a protective agent against β amyloid toxicity. Our results suggest a relevant function for both neuropeptides against β amyloid toxicity, providing new insights into Alzheimer's disease. © 2011 Wiley Periodicals, Inc.
Interleukin‐10 overexpression does not synergize with the neuroprotective action of RGD‐containing vectors after postnatal brain excitotoxicity but modulates the main inflammatory cell responses
Authors: Gonzalez Pau , Peluffo Hugo , Acarin Laia , Villaverde Antonio , Gonzalez Berta , Castellano Bernardo
Published: September 2011

Antiinflammatory cytokines such as interleukin‐10 (IL‐10) have been used to modulate and terminate inflammation and provide neuroprotection. Recently, we reported that the modular recombinant transfection vector NLSCt is an efficient tool for transgene overexpression in vivo, which induces neuroprotection as a result of its RGD‐mediated integrin‐interacting capacity. We here sought to evaluate the putative synergic neuroprotective action exerted by IL‐10 overexpression using NLSCt as a transfection vector after an excitotoxic injury to the postnatal rat brain. For this purpose, lesion volume, neurodegeneration, astroglial and microglial responses, neutrophil infiltration, and proinflammatory cytokine production were analyzed at several survival times after intracortical NMDA injection in postnatal day 9 rats, followed by injection of NLSCt combined with the IL‐10 gene, a control transgene, or saline vehicle solution. Our results show no combined neuroprotective effect between RGD‐interacting vectors and IL‐10 gene therapy; instead, IL‐10 overexpression using NLSCt as transfection vector increased lesion volume and neuronal degeneration at 12 hr and 3 days postlesion. In parallel, NLSCt/IL‐10 treated animals displayed increased density of neutrophils and microglia/macrophages, and a reduced astroglial content of GFAP and vimentin. Moreover, NLSCt/IL‐10 treated animals did not show any variation in interleukin‐1β or tumor necrosis factor‐α expression but a slight increase in interleukin‐6 content at 7 days postlesion. In conclusion, overexpression of IL‐10 by using NLSCt transfection vector did not synergistically neuroprotect the excitotoxically damaged postnatal rat brain but induced changes in the astroglial and microglial and inflammatory cell response. © 2011 Wiley Periodicals, Inc.
Using distance sampling and hierarchical models to improve estimates of Dall's sheep abundance
Authors: Schmidt Joshua H. , Rattenbury Kumi L. , Lawler James P. , Maccluskie Margaret C.
Published: September 2011

Management of large mammal populations has often been based on aerial minimum count surveys that are uncorrected for incomplete detection and lack estimates of precision. These limitations can be particularly problematic for Dall's sheep (Ovis dalli dalli) due to the high cost of surveys and variation in detection probability across time and space. The limitations of these methods have been recognized for some time, but previously proposed alternatives for sheep surveys proved to be too costly and logistically unfeasible in most circumstances (Udevitz et al. 2006). We assessed the potential for a combination of distance sampling surveys and a hierarchical modeling approach to provide a more efficient means for estimating Dall's sheep abundance by conducting aerial contour transect surveys over all sheep habitat in Gates of the Arctic National Park and Preserve (GAAR), Alaska in 2009 and 2010. We estimated the population of Dall's sheep was 8,412 (95% CI: 6,517–11,090) and 10,072 (95% CI 8,081–12,520) in 2009 and 2010, respectively. Abundance within the Itkillik Preserve area within GAAR was 1,898 (95% CI: 1,421–2,578) and 1,854 (95% CI: 1,342–2,488) in 2009 and 2010, respectively. Estimates of lamb abundance in 2010 were more than double those of 2009 after correcting for detection bias related to group size, suggesting that the apparent estimate of lambs in the population may be biased in some years depending on the degree of aggregation. Overall, the contour transect surveys were feasible logistically, cost 70–80% less than minimum count surveys, and produced precise estimates of abundance, indicating that the application of these methods could be used effectively to increase the statistical rigor and spatial extent of Dall's sheep abundance surveys throughout Alaska. These methods could be used to improve the assessment of long‐term trends in populations and productivity and provide valuable information for harvest management at both local and landscape scales at reduced costs in comparison to traditional minimum count surveys. © 2011 The Wildlife Society.
Effects of rangeland management on the site occupancy dynamics of prairie‐chickens in a protected prairie preserve
Authors: McNew Lance B. , Prebyl Thomas J. , Sandercock Brett K.
Published: September 2011

We investigated the site occupancy dynamics of greater prairie‐chickens at Konza Prairie Biological Station, a protected site in northeastern Kansas that is managed for ecological research. We surveyed the site during mid‐Mar to mid‐May, 1981–2008, and recorded detections of birds in a grid of 6.3 ha survey plots (n = 187 plots). We used multiseason occupancy models to estimate the probabilities of occupancy (ψ) and detection (p), and tested whether land cover in woody vegetation, and land use with prescribed fire or grazing management influenced the dynamic processes of site colonization and local extinction. Probability of detection per site was consistently <1 and varied among years (p = 0.12–0.82). Site occupancy of prairie‐chickens declined 40% over the study period from a high ofψ = 0.19 ± 0.02 SE in 1981 to a low of 0.11 ± 0.03 in 2008, despite protection from disturbance at leks and losses to harvest. We found that different sets of environmental factors impacted the probabilities of colonization and local extinction. Probability of colonization for an unoccupied site was negatively associated with the proportion of site occupied by woodland cover (β = −1.25), and was lower for grazed sites (β = −0.62). In contrast, probability of local extinction was affected by a weak interaction between grazing and average frequency of prescribed fire (β = −1.01), but model‐averaged slope coefficients were not statistically different than 0. To conserve prairie‐chickens, we recommend prairies be managed with combinations of prescribed fire and grazing that maintain a heterogeneous mosaic of prairie habitats, while preventing woody encroachment. To assess biotic responses to land management practices, field sampling should be based on occupancy models or similar techniques that account for imperfect detection. © 2011 The Wildlife Society.
Cost‐efficient selection of a marker panel in genetic studies
Authors: Sanderlin Jamie S. , Lazar Nicole , Conroy Michael J. , Reeves Jaxk
Published: September 2011

Genetic techniques are frequently used to sample and monitor wildlife populations. The goal of these studies is to maximize the ability to distinguish individuals for various genetic inference applications, a process which is often complicated by genotyping error. However, wildlife studies usually have fixed budgets, which limit the number of genetic markers available for inclusion in a study marker panel. Prior to our study, a formal algorithm for selecting a marker panel that included genotyping error, laboratory costs, and ability to distinguish individuals did not exist. We developed a constrained nonlinear programming optimization algorithm to determine the optimal number of markers for a marker panel, initially applied to a pilot study designed to estimate black bear abundance in central Georgia. We extend the algorithm to other genetic applications (e.g., parentage or population assignment) and incorporate possible null alleles. Our algorithm can be used in wildlife pilot studies to assess the feasibility of genetic sampling for multiple genetic inference applications. © 2011 The Wildlife Society.
On the selectivity and efficacy of defense peptides with respect to cancer cells
Authors: Harris Frederick , Dennison Sarah R. , Singh Jaipaul , Phoenix David A.
Published: September 2011

Here, we review potential determinants of the anticancer efficacy of innate immune peptides (ACPs) for cancer cells. These determinants include membrane‐based factors, such as receptors, phosphatidylserine, sialic acid residues, and sulfated glycans, and peptide‐based factors, such as residue composition, sequence length, net charge, hydrophobic arc size, hydrophobicity, and amphiphilicity. Each of these factors may contribute to the anticancer action of ACPs, but no single factor(s) makes an overriding contribution to their overall selectivity and toxicity. Differences between the anticancer actions of ACPs seem to relate to different levels of interplay between these peptide and membrane‐based factors. © 2011 Wiley Periodicals, Inc. Med Res Rev
32‐Channel RF coil optimized for brain and cervical spinal cord at 3 T
Authors: Cohen‐Adad J. , Mareyam A. , Keil B. , Polimeni J. R. , Wald L. L.
Published: September 2011

Panel a: Example of DW images of the spinal cord at 0.6 × 0.6 × 5 mm3 spatial resolution. Dorsal/ventral roots were visible on the second eigenvector. Panel b: Full brain + c‐spine tractography from 1.7‐mm isotropic DTI acquisition using the 32‐channel coil with head paddle (74 sagittal slices, TR/TE = 14,280/80 ms, R = 3, b‐value = 800 s/mm2, 30 diffusion‐directions). No distortion correction was applied. From the article by Cohen‐Adad et al (pp 1199‐1209).
Identification of esophageal cancer in the General Practice Research Database
Authors: Walker Alexander M.
Published: September 2011

Background

Studies based on the first appearance of a code for esophageal cancer in the General Practice Research Database (GPRD) have yielded conflicting results concerning the relationship between disease onset and prior bisphosphonate use. The literature on the timing of cancer code appearance in general practice records is scanty but suggests that there may be substantial error by comparison with actual dates of clinical onset.

Objectives

To assess the accuracy of codes for esophageal cancer in the GPRD and to determine whether it was possible to infer clinical date of onset.

Methods

A reviewer adjudicated the records of women with codes for esophageal cancer from 1996 to 2008 by using chronological GPRD listings of codes for diagnoses, services, and tests. GPRD staff sought reviews by the general practices for 75 women whom the reviewer classified as having esophageal cancer and 25 classified as not having the condition.

Results

Essentially all cases bearing a code for the condition had esophageal cancer. Where data were available to permit dating of clinical onset (75% of cases), the result agreed with the date recorded in the clinical record to within 60 days in 89% of cases. The remaining 25% of cases had little or no clinical information and could not be dated. Clinical onset preceded the first appearance of a cancer code by more than 6 months in 10% of cases.

Conclusions

The accurate timing of clinical onset and diagnosis in the GPRD, at least of esophageal cancer in women, may require the review of clinical records or future linkage to cancer registries. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of poly(N‐isopropylacrylamide) with a low molecular weight and a low polydispersity index by single‐electron transfer living radical polymerization
Authors: Turan Eylem , Zengi̇n Adem , Caykara Tuncer
Published: September 2011

The single‐electron transfer living radical polymerization (SET‐LRP) method in the presence of chain transfer agent was used to synthesize poly(N‐isopropylacrylamide) [poly(NIPAM)] with a low molecular weight and a low polydispersity index. This was achieved using Cu(I)/2,2′‐bipyridine as the catalyst, 2‐bromopropionyl bromide as the initiator, 2‐mercaptoethanol as the chain transfer agent (TH), and N,N‐dimethylformamide (DMF) as the solvent at 90 °C. The copper nanoparticles with diameters of 16 ± 3 nm were obtained in situ by the disproportionation of Cu(I) to Cu(0) and Cu(II) species in DMF at 22 °C for 24 h. The molecular weights of poly(NIPAM) produced were significantly higher than the theoretical values, and the polydispersities were less than 1.18. The chain transfer constant (Ctr) was found to be 0.051. Although the kinetic analysis of SET‐LRP in the presence of TH corroborated the characteristics of controlled/living polymerization with pseudo‐first‐order kinetic behavior, the polymerization also exhibited a retardation period (k > ktr). The influence of molecular weight on lower critical solution temperature (LCST) was investigated by refractometry. Our experimental results explicitly elucidate that the LCST values increase slightly with decreasing molecular weight. Reversibility of solubility and collapse in response to temperature well correlated with increased molecular weight of poly(NIPAM). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011