bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anion Binding versus Intramolecular Hydrogen Bonding in Neutral Macrocyclic Amides
Authors: Chmielewski Michał J. , Jurczak Janusz 
Published: July 2006

AbstractAlthough amide groups are important hydrogen‐bond donors in natural and synthetic anion receptors, studies on structure–affinity relationships of amide‐based macrocyclic receptors are still very limited. Therefore, we synthesized a series of macrocyclic tetraamides 5–8 derived from 1,3‐benzenedicarboxylic (isophthalic) acid and aliphatic α,ω‐diamines of different lengths. 1H NMR titrations in DMSO solution show that the anion affinity of these receptors decreases with increasing size of the macrocycle irrespective of the anion, and this suggests a minor role of geometric complementarity. Comparison with their previously studied pyridine congeners reveals that the isophthalic acid based macrocycles are less potent, in contrast to what was found for simple model diamides. Combined theoretical and experimental structural studies were carried out to determine the reasons behind this behaviour. The results show that the unexpectedly low anion binding ability of the isophthalic acid‐based receptors is due to the self‐complementary nature of the isophthalic bis‐amide fragments: when two such moieties are present within a sufficiently flexible macrocycle, they adopt syn–anti conformations and bind each other by two strong intramolecular hydrogen bonds that close the macrocyclic cavity. Nevertheless, anion binding is able to break these hydrogen bonds and switch a macrocycle into a convergent all‐syn conformation. Despite the ill‐preorganized conformation, 20‐membered receptor 6 is better than either its open‐chain analogue (macrocyclic effect) and/or its isomer having differently placed carbonyl groups. The crystal structures of four anion complexes of the macrocyclic receptors are reported. X‐ray studies and solution NMR data confirmed the inclusive nature of the complexes and pointed to strong involvement of aromatic CH hydrogen atoms in anion binding.
C20 Carbon Clusters: Fullerene–Boat–Sheet Generation, Mass Selection, Photoelectron Characterization
Authors: Prinzbach Horst , Wahl Fabian , Weiler Andreas , Landenberger Peter , Wörth Jürgen , Scott Lawrence T. , Gelmont Marc , Olevano Daniela , Sommer Frank , von Issendorff Bernd 
Published: July 2006

AbstractElectron‐impact ionization in a time‐of‐flight mass spectrometer of C20H0–3Br14–12 probes—secured from C20H20 dodecahedrane by a “brute‐force” bromination protocol—provided bromine‐free C20H0–2(3) anions in amounts that allowed the clean mass‐separation of the hydrogen‐free C20− ions and the photoelectron (PE) spectroscopic characterization as C20 fullerene (electron affinity (EA)=2.25±0.03 eV, vibrational progressions of 730±70). The extremely strained C20 fullerene ions surfaced as kinetically rather stable entities (lifetime of at least the total flight time of 0.4 ms); they only very sluggishly expel a C2 unit. The HOMO and LUMO are suggested to be almost degenerate (ΔE=0.27 eV). The assignment as a fullerene was corroborated by the PE characterization of the C20 bowl (EA=2.17±0.03 eV, vibrational progression of 2060±50 cm−1) analogously generated from C20H10 corannulene (C20H1–3Br9–8 samples) and comparably stable. Highly resolved low‐temperature PE spectra of the known C20 ring (EA=2.49±0.03 eV, vibrational progressions 2022±45 and 455±30 cm−1), obtained from graphite, display an admixture of, most probably, a bicyclic isomer (EA=3.40±0.03 eV, vibrational progression 455±30 cm−1). The C20+(−) and C20H2+(−) cluster ions generated from polybrominated perylene (C20H0–2Br12–10) have (most probably) retained the planar perylene‐type skeleton (sheet, EA=2.47±0.03 eV, vibrational progressions of 2089±30 and 492±30 cm−1 and EA=2.18±0.03 eV, vibrational progressions of 2105±30 and 468±30 cm−1).
Synthesis and Electrochemical Properties of Semicrystalline Gyroidal Mesoporous MnO2
Authors: Zhou Qin , Li Xiang , Li Yan‐Guang , Tian Bo‐Zhi , Zhao Dong‐Yuan , Jiang Zhi‐Yu 
Published: July 2006

AbstractMesoporous silica KIT‐6 has novel three‐dimensional gyroidal channel structure, space group of Ia‐3d, and ordered tunable pores up to 10 nm. In this paper, such mesostructured silica was employed as hard template to prepare semicrystalline gyroidal mesoporous MnO2. The structure was investigated by XRD, TEM and HRTEM, and found to be of high quality Ia‐3d symmetry, in good accordance with the template structure. The material has a BET surface of 118 m2·g‐1 and pore volume of 0.35 cm3·g−1 after eliminating template. Mesoporous MnO2 has shown good electrochemical property as supercapacitor material in 1 mol·L−1 Na2SO4 and 1 mol·L−1 LiClO4 solutions, but interesting pseudocapacitance behavior was observed in the case of 6 mol·L−1 KOH. It was found that mesoporous MnO2 performed stable reversible electrochemical behavior with capacitance of 220 F·g−1 in a potential range of −0.1–0.55 V vs. Hg/HgO in alkaline solution, demonstrating that it is a promising novel electrode material for the fabrication of electrochemical capacitors.
Highly Selective Salicylate Membrane Electrode Based onN,N′‐(Aminoethyl)ethylenediamide Bis(2‐salicylideneimine) Binuclear Copper(II) Complex as Neutral Carrier
Authors: Sun Ai‐Li , Cai Ya‐Qin , Yuan Ruo , Gui Guo‐Feng 
Published: July 2006

AbstractA new ion selective electrode for salicylate based onN,N′‐(aminoethyl)ethylenediamide bis(2‐salicylideneimine) binuclear copper(II) complex [Cu(II)2‐AEBS] as an ionophore was developed. The electrode has a linear range from 1.0×10−1to 5.0×10−7mol·L−1with a near‐Nernstian slope of (−55±1) mV/decade and a detection limit of 2.0×10−7mol·L−1in phosphorate buffer solution of pH 5.0 at 25 °C. It shows good selectivity for Sal−and displays anti‐Hofmeister selectivity sequence:Sal−>SCN−>ClO−4>I−>NO−2>Br−>NO−3>Cl−>SO2−3>SO2−4. The proposed sensor based on binuclear copper(II) complex has a fast response time of 5–10 s and can be used for at least 2 months without any major deviation. The response mechanism is discussed in view of the alternating current (AC) impedance technique and the UV‐vis spectroscopy technique. The effect of the electrode membrane compositions and the experimental conditions were studied. The electrode has been successfully used for the determination of salicylate ion in drug pharmaceutical preparations.
Validation of the functional assessment of cancer therapy esophageal cancer subscale
Authors: Darling Gail , Eton David T. , Sulman Joanne , Casson Alan G. , Cella David 
Published: July 2006

AbstractBACKGROUND.To develop and validate a quality of life subscale for patients with esophageal cancer to be used with the Functional Assessment of Cancer Therapy—General (FACT‐G).METHODS.Prospective cohort study of patients with esophageal cancer treated with surgery alone or neoadjuvant chemoradiotherapy and surgery evaluating the validity, internal consistency, and responsiveness to change of the FACT‐Esophageal (FACT‐E) when comparing it with the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ 30) and esophageal (OES 24) as well as clinical factors.RESULTS.The FACT‐E demonstrated very good convergent and divergent validity when compared with the EORTC QLQ30 and OES 24 and clinical variables. Internal consistency was also good with coefficient α >0.70 for all subscales and individual items. Stability coefficients were >0.80. Changes in clinical status were reflected in changes in FACT‐E scores demonstrating responsiveness to change, particularly in patients receiving neoadjuvant chemoradiotherapy before surgery.CONCLUSIONS.The FACT‐E met or exceeded all standards for validity, providing an option to measure health‐related quality of life for different treatment strategies for esophageal cancer. Cancer 2006. © 2006 American Cancer Society.
Variations in reconstruction after radical cystectomy
Authors: Gore John L. , Saigal Christopher S. , Hanley Jan M. , Schonlau Matthias , Litwin Mark S. ,   and the Urologic Diseases in America Project
Published: July 2006

AbstractBACKGROUND.Most urologists specializing in the management of patients with bladder cancer consider continent urinary diversion the reconstructive technique that affords the best quality of life after radical cystectomy. The authors sought to evaluate factors that predict reconstructive technique after radical cystectomy.METHODS.Using linked data from Medicare and the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program, 3611 subjects were identified who underwent radical cystectomy for bladder cancer between 1992 and 2000. Multivariate logistic regression was used to identify factors independently associated with utilization of continent reconstruction after radical cystectomy, incorporating patient and provider variables.RESULTS.In multivariate analysis, the likelihood of continent diversion was inversely associated with older age (odds ratio [OR] ≤0.68, P ≤ .002), African American race (OR 0.43, P = .003), and higher comorbidity index (OR 0.71, P = .03), and directly associated with male sex (OR 1.45, P = .002), higher education level (OR 1.54, P = .03), and year of surgery (OR ≥ 1.56, P < .001 for all year categories vs. 1992–1994). Treatment at academic (OR 1.43, P = .003) and NCI‐designated cancer centers (OR 5.50, P < .001) and by high‐volume providers (OR 1.49, P < .001) was independently associated with continent reconstruction.CONCLUSIONS.Disparities in the utilization of continent urinary diversion after radical cystectomy suggest that demographic, socioeconomic, provider‐based, and clinical variables predict the likelihood that those undergoing radical cystectomy will receive continent reconstruction. Regionalization of bladder cancer care may ameliorate many of the disparities noted but must be balanced against the risk imposed by a delay in care. Cancer 2006. © 2006 American Cancer Society.
Nucleation and Growth of Boron Nanowires on ZrB2 Particles
Authors: Guo L. , Singh R. N. , Kleebe H.‐J. 
Published: July 2006

AbstractAmorphous boron rich nanowires are grown on ZrB2 particles using diborane as the gas precursor in a CVD process under 20 Torr pressure and at 900 °C. These nanowires have uniform diameters of tens of nanometers and lengths of up to several micrometers. The boron‐rich nanowires are characterized and found to be composed of boron clusters containing unit cells of icosahedral B12. A surface nucleation and growth mechanism of solid boron from vapor phase is proposed to explain the nanowire growth. The role of ZrB2 particles in the synthesis of the boron‐rich nanostructures is also discussed.
Algebraic multigrid and incompressible fluid flow
Authors: Webster R. 
Published: July 2006

AbstractThis paper is concerned with the development of algebraic multigrid (AMG) solution methods for the coupled vector–scalar fields of incompressible fluid flow. It addresses in particular the problems of unstable smoothing and of maintaining good vector–scalar coupling in the AMG coarse‐grid approximations. Two different approaches have been adopted. The first is a direct approach based on a second‐order discrete‐difference formulation in primitive variables. Here smoothing is stabilized using a minimum residual control harness and velocity–pressure coupling is maintained by employing a special interpolation during the construction of the inter‐grid transfer operators. The second is an indirect approach that avoids the coupling problem altogether by using a fourth‐order discrete‐difference formulation in a single scalar‐field variable, primitive variables being recovered in post‐processing steps. In both approaches the discrete‐difference equations are for the steady‐state limit (infinite time step) with a fully implicit treatment of advection based on central differencing using uniform and non‐uniform unstructured meshes. They are solved by Picard iteration, the AMG solvers being used repeatedly for each linear approximation.Both classical AMG (C‐AMG) and smoothed‐aggregation AMG (SA‐AMG) are used. In the direct approach, the SA‐AMG solver (with inter‐grid transfer operators based on mixed‐order interpolation) provides an almost mesh‐independent convergence. In the indirect approach for uniform meshes, the C‐AMG solver (based on a Jacobi‐relaxed interpolation) provides solutions with an optimum scaling of the convergence rates. For non‐uniform meshes this convergence becomes mesh dependent but the overall solution cost increases relatively slowly with increasing mesh bandwidth. Copyright © 2006 John Wiley & Sons, Ltd.
Alluvial geoarchaeology of a Middle Archaic Mound complex in the lower Mississippi Valley, U.S.A.
Authors: Arco Lee J. , Adelsberger Katherine A. , Hung Ling‐yu , Kidder Tristram R. 
Published: July 2006

AbstractThe Nolan site (16MA201), 14C dated 5200–4800 cal yr B.P. and located in the Tensas Basin of northeastern Louisiana, is the only recorded Middle Archaic mound site in the alluvial valley of the Mississippi River. Alluvial deposition has buried the Nolan site under 3–4 m of Holocene sediment, prohibiting traditional excavation of the site. Because data are unattainable by other means, soil coring and subsequent stratigraphic and sedimentological analyses permit reconstruction of the natural and cultural depositional history of the Nolan site. The sedimentary characteristics of basal deposits within cores suggest the presence of an Arkansas River paleochannel immediately adjacent to the site. Chronostratigraphic data show this channel was no longer active by ca. 5200 cal yr B.P. Contrary to existing models, the Arkansas River Meander Belt 4 and the Mississippi River Meander Belt 4 are not the same age. Microartifact and losson‐ignition analyses of sediment identify natural versus cultural strata and permit the identification of artificial constructions—including four earthen mounds and one earthen ridge—at the Nolan site. Overbank sediments attributed to a mapped Mississippi River Stage 4 meander belt are dated ca. 4800–3800 cal yr B.P. This age is considerably younger than previous estimates and demonstrates the existing chronological models for Mississippi River meander belts must be carefully assessed. Core analyses also reveal flood‐related crevasse splays deposited throughout the Tensas Basin after the occupation of the Nolan site. These deposits serve as relative chronological indicators and aid in stratigraphic assessments of the Nolan site. Reconstruction of the earthworks and their stratigraphic context reveals one of the largest and earliest Middle Archaic mound sites in North America. © 2006 Wiley Periodicals, Inc.
Effect of cyanidin‐3‐glucoside and an anthocyanin mixture from bilberry on adenoma development in the ApcMin mouse model of intestinal carcinogenesis—Relationship with tissue anthocyanin levels
Authors: Cooke Darren , Schwarz Michael , Boocock David , Winterhalter Peter , Steward William P. , Gescher Andreas J. , Marczylo Timothy H. 
Published: July 2006

AbstractAnthocyanins are dietary flavonoids, which can prevent carcinogen‐induced colorectal cancer in rats. Here, the hypotheses were tested that Mirtoselect, an anthocyanin mixture from bilberry, or isolated cyanidin‐3‐glucoside (C3G), the most abundant anthocyanin in diet, interfere with intestinal adenoma formation in the ApcMin mouse, a genetic model of human familial adenomatous polyposis, and that consumption of C3G or Mirtoselect generates measurable levels of anthocyanins in the murine biophase. ApcMin mice ingested C3G or Mirtoselect at 0.03, 0.1 or 0.3% in the diet for 12 weeks, and intestinal adenomas were counted. Plasma, urine and intestinal mucosa were analyzed for presence of anthocyanins by high‐pressure liquid chromatography with detection by UV spectrophotometry (520 nm) or tandem mass spectrometry (multiple reaction monitoring). Ingestion of either C3G or Mirtoselect reduced adenoma load dose‐dependently. At the highest doses of C3G and Mirtoselect adenoma numbers were decreased by 45% (p < 0.001) or 30% (p < 0.05), respectively, compared to controls. Anthocyanins were found at the analytical detection limit in the plasma and at quantifiable levels in the intestinal mucosa and urine. Anthocyanin glucuronide and methyl metabolites were identified in intestine and urine. Total anthocyanin levels in mice on C3G or Mirtoselect were 43 ng and 8.1 μg/g tissue, respectively, in the intestinal mucosa, and 7.2 and 12.3 μg/ml in the urine. The efficacy of C3G and Mirtoselect in the ApcMin mouse renders the further development of anthocyanins as potential human colorectal cancer chemopreventive agents worthwhile. © 2006 Wiley‐Liss, Inc.
Heat‐induced phosphorylation of NBS1 in human skin fibroblast cells
Authors: Ohnishi Ken , Scuric Zorica , Yau David , Schiestl Robert H. , Okamoto Noritomo , Takahashi Akihisa , Ohnishi Takeo 
Published: July 2006

AbstractNBS1 is known to be involved in DNA damage‐induced cellular responses after exposure to ionizing radiation (IR). Phosphorylation of NBS1 contributes to cell‐cycle checkpoints. The aim of this study was to determine whether heat exposure induces or stimulates cellular responses mediated by the phosphorylation of NBS1 in human skin fibroblast cell lines. The results of immunofluorescent staining and Western blot analysis showed that NBS1 proteins are phosphorylated after exposure to heat in the nucleus of a normal skin fibroblast cell line (82‐6 cells). This suggests that the NBS1‐mediated signal transduction could be induced by heat. We further examined whether a deficiency in the NBS1 protein modifies heat sensitivity in human skin fibroblast cell lines. A skin fibroblast cell line (Gmtert), derived from a Nijmegen breakage syndrome (NBS) patient containing mutant NBS1, showed higher sensitivity to heat than the same cell line transfected with the wild‐type copy of the NBS1 gene. We also showed that transfection of a DNA cassette expressing small interference RNA (siRNA) targeted to NBS1 into 82‐6 cells enhanced cell sensitivity to heat. These results suggest that NBS1 is involved in cellular responses to DNA damage which is induced by heat exposure as well as by radiation exposure in human skin fibroblast cells. J. Cell. Biochem. 99: 1642–1650, 2006. © 2006 Wiley‐Liss, Inc.
Oviduct contraction in Drosophila is modulated by a neural network that is both, octopaminergic and glutamatergic
Authors: Rodríguez‐Valentín Rocío , López‐González Ignacio , Jorquera Ramón , Labarca Pedro , Zurita Mario , Reynaud Enrique 
Published: July 2006

AbstractFertility is a highly complex and regulated phenomenon essential for the survival of any species. To identify Drosophila fertility‐specific neural networks, we used a GAL4/UAS enhancer trap genetic screen that selectively inactivates groups of neurons. We identified a GAL4 line (bwktqs) that has a female sterile phenotype only when it expresses the tetanus toxin light chain (TeTxLC). These flies lack oviduct contraction, lay almost no eggs, sperm accumulate in the oviducts, and fewer than normal are seen in the storage organs. In insects, two neuroactive substances are important for oviduct contraction: octopamine (OA), a monoamine that inhibits oviduct contraction, and glutamate (Glu), a neurotransmitter that induces contraction. It is known that octopaminergic neurons of the thoracic abdominal ganglion (TAG) modulate oviduct contraction, however, the glutamatergic neurons that innervate the oviduct have not been identified yet and the interaction between these two neuroactive substances is not well understood. Immunostaining experiments revealed that the bwktqs line trapped an octopaminergic neural network that innervates the genital tract. We show that wt like oviduct contraction in TeTxLC‐inactivated flies can only be rescued by simultaneous application of Glu and OA suggesting that the abdominal bwktqs neurons are both octopaminergic and glutamatergic, the use of an agonist and an antagonist for Glu receptors as well as their direct visualization confirmed its participation in this phenomenon. Our work provides the first evidence that adult abdominal type II visceral innervations co‐express Glu and OA and allows us to re‐evaluate the previous model of neuronal network controlling insect oviduct contraction. J. Cell. Physiol. 209: 183–198, 2006. © 2006 Wiley‐Liss, Inc.
Regulation of Ang2 release by PTEN/PI3‐kinase/Akt in lung microvascular endothelial cells
Authors: Tsigkos Stelios , Zhou Zongmin , Kotanidou Anastasia , Fulton David , Zakynthinos Spyros , Roussos Charis , Papapetropoulos Andreas 
Published: July 2006

AbstractAngiopoietin‐2 (Ang2) is a Tie‐2 ligand that destabilizes vascular structures, allowing for neovascularization or vessel regression depending on local vascular endothelial cell growth factor (VEGF) concentrations. Although various stimuli have been shown to affect Ang2 expression, information on the underlying mechanisms involved in Ang2 production in endothelial cells (EC) is just beginning to emerge. In the present study, we have used adenovirus‐mediated gene transfer and pharmacological inhibitors to examine the role of the PTEN/PI3‐K/Akt pathway on Ang2 release. Inhibition of PI3‐kinase with wortmannin led to a stimulation of basal Ang2 release in EC, while overexpression of an active form of Akt reduced Ang2. In addition, adenovirus‐mediated gene transfer of the phosphatase PTEN stimulated Ang2 release. Incubation of the cells with Ang1, an agent that activates the PI3‐K/Akt pathway in EC, reduced Ang2 release. This effect of Ang1 could be prevented by wortmannin and LY‐294002 pretreatment. Similarly, in VEGF‐treated EC the increase in Ang2 production observed was greater in the presence of a PI3‐K inhibitor. Our observations that PTEN acts as a positive modulator of Ang2 release, while activation of the PI3‐K/Akt pathway downregulates Ang2, reveal an additional mechanism through which the PTEN/PI3‐K/Akt pathway could affect the angiogenic process. J. Cell. Physiol. 209: 239, 2006. © 2006 Wiley‐Liss, Inc.
Combined electrochemical and biological treatment of industrial wastewater using porous electrodes
Authors: Doan Huu D , Wu Jiangning , Mitzakov Robert 
Published: July 2006

AbstractZn2+, Ni2+ and propylene glycol methyl ether were simultaneously removed from simulated wastewater in a column consisting of an aerated packed bed and an electrochemical cell with a porous aluminium foam cathode and a porous stainless steel anode. After 48 h of sole electrochemical treatment at a liquid rate of 0.00183 m3 m−2 s−1, Zn2+ and Ni2+ were reduced by 95 and 80% respectively. In the turbulent flow regime with liquid rates varied from 0.0137 to 0.0366 m3 m−2 s−1, both Zn2+ and Ni2+ removal decreased by about 15% rather than increased as expected for a mass transfer‐controlled process. This can be attributed to bubble formation at the cathode surface under turbulent flow, which led to a lower active surface area for the electrodeposition of metal ions. Porous electrodes enhanced the metal removal by 17 and 60% for Zn2+ and Ni2+ respectively as compared with flat plate electrodes. Using combined biological and electrochemical treatment at a water rate of 0.00183 m3 m−2 s−1 and an air rate of 0.0518 m3 m−2 s−1, 99% of Zn2+ and 95% of Ni2+ were removed. In addition, the 5 day biological oxygen demand (BOD5) was reduced by 58% concurrently over 72 h of treatment. Copyright © 2006 Society of Chemical Industry