bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological effects of Ni nanostructures on electropolymerization of aniline
Authors: Eftekhari Ali , Yazdani Bahareh 
Published: May 2011

AbstractElectrochemical polymerization of aniline on nanostructured Ni substrates was investigated. To this aim, the Ni substrate electrodes were prepared by casting various samples of Ni nanoparticles having different morphologies. The electropolymerization on these different nanostructured Ni substrates was systematically investigated by means of comparative results obtained from cyclic voltammetry and electron microscopy as representatives of electrochemical behavior and morphology, respectively. Since the Ni nanoparticles are the beginning sites for the polymer growth, polyaniline morphology is strongly controlled by the nature of the Ni nanoparticles associated with chemical properties rather than geometrical shape. In conclusions, although the substrate surfaces had a similar nanostructure, but due to the difference in their chemical properties, the morphologies electrochemical behaviors of the polyaniline films electrodeposited on these substrates are significantly different. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Carnauba straw: Characterization and chemical treatments
Authors: Fernandes Jéssica Emanuela , Dantas Tereza Neuma de Castro , Fonseca José Luís Cardozo , Pereira Márcia Rodrigues 
Published: May 2011

AbstractThe influence of chemical modifications, such as dewaxing with hexane and carbon tetrachloride, and alkaline treatment, on the mechanical, thermal, and sorption properties of carnauba straw was investigated for the first time. Scanning electron microscopy showed that the solvent treatments removed the wax layer, exposing the straw fibrils. The straw water sorption capacity was very high, and the treatments turned it from Fickian to non‐Fickian. The results show that the solvents used were very effective in removing the surface wax layer, whereas alkali, on the other hand, promoted a more marked change in the chemical structure of the straw. The chemical treatments demonstrated that the wax surface layer was very important in determining the final properties of this material and that its removal reduced the thermal stability and Young's modulus from 143 to 48 MPa and increased its hydrophilicity, changing the contact angle from 90 to 60°. As a result, carnauba straw is a potentially promising material to be used, for example, as a natural fiber with polymer matrices for the manufacture of low‐cost, ecofriendly composite materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Neurochemical and Structural Organization of the Principal Nucleus of the Inferior Olive in the Human
Authors: Baizer Joan S. , Sherwood Chet C. , Hof Patrick R. , Witelson Sandra F. , Sultan Fahad 
Published: May 2011

AbstractThe inferior olive (IO) is the sole source of the climbing fibers that innervate the Purkinje cells of the cerebellar cortex. The IO comprises several subdivisions, the dorsal accessory olive (DAO), medial accessory olive (MAO), and principal nuclei of the IO (IOpr); the relative sizes of these subnuclei vary among species. In human, there is an expansion of the cerebellar hemispheres and a corresponding expansion of the IOpr. We have examined the structural and neurochemical organization of the human IOpr, using sections stained with cresyl violet (CV) or immunostained for the calcium‐binding proteins calbindin (CB), calretinin (CR), and parvalbumin (PV), the synthetic enzyme for nitric oxide (nNOS), and nonphosphorylated neurofilament protein (NPNFP). We found qualitative differences in the folding patterns of the IOpr among individuals and between the two sides of the brainstem. Quantification of IOpr volumes and indices of folding complexity, however, did not reveal consistent left–right differences in either parameter. Single‐label immunohistochemistry showed that populations of neurons in the IOpr express CB, CR, NPNFP, and nNOS. Individual fibers labeled for PV, CB, CR, NPNFP, and nNOS were also found. There was individual variability in the numbers and density of stained neurons in the human IOpr; such variability was not seen in other brainstem nuclei. These data are consistent with, and complement, earlier studies showing a dramatic age‐related increase in lipofuscin and decrease in RNA in the human IOpr. The impact of these changes in the IOpr on cerebellar function is, however, not known. Anat Rec,, 2011. © 2011 Wiley‐Liss, Inc.
The Expression Pattern of Polycomb Group Protein Ezh2 During Mouse Embryogenesis
Authors: Ningxia Zhu , Shuyan Liu , Zhongjing Su , Ling Chen , Tianzhong Ma , Lifeng Wen , Yan Yuan , Leili Lv , Xiancai Chen , Haibin Chen 
Published: May 2011

AbstractThe Polycomb group (PcG) family proteins are required for the stability of homeotic selector genes and other genes related to the regulation of mammalian development through their roles in the modulation of chromatin domains. Among them, the mammalian enhancer zeste homologue 2 (Ezh2) contributes to the transcriptional repression of these genes. Previous studies tracked the Ezh2 expression at cDNA and mRNA levels during mouse development. However, little information is known about the expression patterns of Ezh2 at the protein levels. In this study, the embryos (E6.5–E18.5) obtained through timed matings of strain Kunming mice were inserted into paraffin blocks. Tissue microarrays were constructed and followed by subsequent immunohistochemical staining. The positive cells were identified and scored based on both the percentage of stained cells and their staining intensities. Ezh2 protein expression was found throughout the embryonic tissues including the nerves, intestine epithelial, liver, pancreas, renal tubule, and lungs. Its expression level was higher at early embryonic developmental stages. However, the nerve fibers and myocardium showed weak or no immunostaining reactivities. Ezh2 protein was moderately expressed in the nuclei of renal tubule epithelial cells at E14.5. In contrast, it was weakly expressed in the fetal kidneys at E18.5 and the protein was localized in the cytoplasm of the renal tubule epithelial cells. Our data confirmed that Ezh2 protein was expressed in mouse embryos and its expression exhibited tissue specificity and dependence on the stages of embryo development. thus providing new information helpful for understanding the possible roles of Ezh2 in embryogenesis. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
In vitro digestive stability of complexes between gliadin and synthetic blocking peptides
Authors: Hoffmann Karolina , Carlsson Nils‐Gunnar , Alminger Marie , Chen Tingsu , Wold Agnes , Olsson Olof , Sandberg Ann‐Sofie 
Published: May 2011

AbstractCeliac disease is caused by an inappropriate immune response to incompletely digested gluten proteins. We investigated whether synthetic peptides with high affinity to wheat gliadin could be selected with a phage display technique and whether complexes between such peptides and gliadin could sustain gastric and pancreatic digestion. Two synthetic peptides, P61 and P64, were selected because of their high affinity to immobilized gliadin. They were allowed to form complexes with gliadin, whereafter the complexes were subjected to in vitro digestion with gastric and pancreatic enzymes. The digestion products were analyzed with Western blot and RP HPLC. The results showed that both peptides formed stable complexes with intact gliadin and that complexes between gliadin and peptide P64 partly resisted gastrointestinal digestion. The two peptides reduced the binding of serum anti‐gliadin IgA antibodies by 12%, and 11.5%, respectively, and the binding of anti‐gliadin antibodies of the IgG isotype by 13% and 10%. Thus peptides produced by a phage display technique could interact stably with gliadin partly masking epitopes for antibody binding. A combination of peptides of this kind may be used to block gliadin‐immune system interactions.
The effect of carbon source supplementation on the production of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) by Cupriavidus necator
Authors: Fereidouni Mohammad , Younesi Habibollah , Daneshi Ali , Sharifzadeh Mazyar 
Published: May 2011

AbstractThe objective of the present study was to investigate the ability of Cupriavidus necator to produce poly‐(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) on various carbon sources in batch cultivation. These results show that C. necator produces poly‐3‐hydroxybutyrate from single carbon sources. The highest poly‐3‐hydroxybutyrate (P3HB) content was achieved at growth on fructose in the exponential growth phase. The maximum yield of the P3HV content was obtained when fructose was mixed with acetate. The highest content P3HB‐co‐3HV was also achieved by C. necator when we supplied C‐excess and N‐ and P‐normal conditions. These results indicate that C. necator accumulates high polyhydroxyalkanoates (PHA) content by depleting these elements in the culture medium. Nitrogen and phosphorus limitation has no significant effect on the PHA production, whereas C‐excess leads to an increase in PHA formation of up to 92% PHAs of cell dry weight after growth on 5 g/L acetate and 40 g/L fructose.
Effects of folic acid fortification on spina bifida prevalence in Brazil
Authors: Orioli Iêda Maria , Lima do Nascimento Ricardo , López‐Camelo Jorge Santiago , Castilla Eduardo Enrique 
Published: May 2011

AbstractBACKGROUND: To assess spina bifida birth prevalence changes after folic acid fortification of wheat and maize flours began in Brazil in June 2004. METHODS: Cross‐sectional study of Brazilian live births in 2004 and 2006. Spina bifida birth prevalence from the Live Births Information System (SINASC: Sistema de Informações sobre Nascidos Vivos) in a prefortified period was compared to a period fortified with folic acid in each state. Observed prevalence rates in 2004 were used to calculate the expected prevalence rates in 2006 under the null hypothesis that both were similar. The observed/expected (O/E) ratios were tested by two‐tailed Z‐test. To minimize ascertainment differences among states, the O/E ratio of each one of the 27 Brazilian states was adjusted for the number of births with the Mantel‐Haenszel statistic. RESULTS The reduction in spina bifida birth prevalence in 2006 was 39% (O/E = 0.61; 95% confidence interval [CI], 0.55‐0.67), and 40% (O/E = 0.60; 95% CI, 0.53–0.68), after adjusting for state birth number. This reduction was significant (p < 0.0001), and heterogeneous among states (χ2 = 72.96; p < 0.0001). CONCLUSIONS: Using SINASC data, there was a significant reduction in spina bifida birth prevalence in Brazil, probably related to the folic acid food fortification program. Birth Defects Research (Part A) 2011. © 2011 Wiley‐Liss, Inc.
Enhanced cellular uptake and metabolic stability of lipo‐oligoarginine peptides
Authors: Lee Jae Sam , Tung Ching‐Hsuan 
Published: May 2011

AbstractDeveloping efficient cellular delivery vectors is crucial for designing novel therapeutic agents to enhance their plasma membrane permeability and metabolic stability in cells. Previously, we engineered cell penetrating peptide vectors named as “lipo‐oligoarginine peptides” (LOAPs) by conjugating a proper combination of fatty acid and oligoarginine that translocated into cell easily without adverse effect on cell viability. In the present study, we report a systemic evaluation of cellular uptake and metabolic stability of LOAPs in Jurkat cells by introducing different combination of D‐Arg residues in the peptide backbone. The cellular uptake and intracellular fate, cell viability, and metabolic stability and proteolytic degradation patterns of various LOAPs consisted of different combination of L‐ and D‐Arg sequences were confirmed by flow cytometry, cytotoxicity assay, and analytical RP‐HPLC with MALDI‐TOF mass. All investigated LOAPs penetrated the cell efficiently with low cellular toxicity. The LOAPs having D‐Arg residues at their N‐termini seemed to have better metabolic stability than the LOAPs having C‐terminal D‐Arg residues. The metabolic degradation patterns were similar among all investigated LOAPs. The major hydrolytic site was between lauroyl group and β‐Ala residue. Without the lipid chain, the oligoarginine peptide was pumped out ofcells easily. The results presented in this study suggest that structurally modified LOAPs could be used as a novel CPP design toward improved therapeutic application. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 772–779, 2011.
Dissecting the Role of Single Regions of an IAPP Mimic and IAPP in Inhibition of Aβ40 Amyloid Formation and Cytotoxicity
Authors: Andreetto Erika , Yan Li‐Mei , Caporale Andrea , Kapurniotu Aphrodite 
Published: May 2011

AbstractAlzheimer's disease (AD) and type 2 diabetes (T2D) are linked to the self‐association of β‐amyloid peptide (Aβ) and islet amyloid polypeptide (IAPP), respectively. We have shown that IAPP‐GI, a soluble IAPP analogue and mimic of nonamyloidogenic and nontoxic IAPP, binds Aβ with high affinity and blocks its cytotoxic self‐assembly and fibrillogenesis. We have also shown that IAPP and Aβ interact with each other into nonfibrillar and nontoxic heterocomplexes that suppress cytotoxic self‐association by both polypeptides. The Aβ–IAPP interaction might thus be a molecular link between AD and T2D. We studied the role of individual IAPP‐GI and IAPP regions in their inhibitory function on Aβ40 self‐association and cytotoxicity. We found that the presence of the two hot‐spot regions of the Aβ–IAPP interaction interface in IAPP(8–28) is not sufficient for inhibitory function and that, in addition to IAPP(8–28), the presence of the N‐terminal region IAPP(1–7) is absolutely required. By contrast, the C‐terminal region, IAPP(30–37), is not required although its presence together with IAPP(1–7) in IAPP‐GI results in a marked enhancement of the inhibitory effect as compared to IAPP(1–28)‐GI. We suggest that the inhibitory effect of IAPP‐GI and IAPP on Aβ40 fibrillogenesis and cell toxicity is mediated primarily by interactions involving the hot regions of the Aβ–IAPP interaction interface and the N terminus of IAPP while a concerted and likely structure‐stabilizing action of the N‐ and C‐terminal IAPP regions potentiates this effect. These results identify important molecular determinants of the amyloid suppressing function of the Aβ40–IAPP interaction and could contribute to the design of novel inhibitors of Aβ40 aggregation and cell degeneration.
Investigation of the mechanism of low‐density particle and liquid mixing process in a stirred vessel
Authors: Chen Tao , Wang Le‐Qin , Wu Da‐Zhuan , Sun You‐Bo , Wu Bo , Li Zhi‐Feng 
Published: May 2011

AbstractIn order to investigate the mechanism of the low‐density solid particle and liquid mixing process, a specialised agitator structure was used. Both computational fluid dynamics simulation and experiments were carried out to study the two‐phase mixing characteristics in the stirred vessel. The mixing process was captured by snapshots. The flow field and solid phase volume fraction evolution were analysed. Experimental and numerical results agreed well with each other. Solid particles floating on the liquid surface were gradually transported to the bottom through the centre of the vessel and the mixing time was predicted and tested. Results indicate that the agitator structure used in this study is able to form an obvious axial circulation in the vessel and then achieve a good performance in low‐density solid and liquid mixing operations. The study provides a valuable reference for the design and optimisation of solid–liquid mixing equipment. © 2011 Canadian Society for Chemical Engineering
Comparing top entry versus side entry agitator performance in low viscosity blending
Authors: Kehn Richard Oliver 
Published: May 2011

AbstractThe primary purpose of this study was to quantify the difference in performance of side entering versus top entering agitators in low viscosity blending on the lab scale. This study compared the power requirement of top entry versus side entry agitator set ups to yield the same blend time. A 1.22 m diameter clear vessel was used for the testing and several top entry set ups (0.15–0.3D/T with three wall baffles) were compared to a single side entry set up (0.09D/T with no wall baffles). Blend time was recorded for each run using three to four conductivity probes with water as the base fluid and a saturated sodium chloride solution as the tracer. Results show that a side entering agitator requires between three and five times the power to yield the same blend time as a top entering agitator. This ratio of powers is strongly related to the D/T chosen. In the future, additional work will be completed, which will include the effect of multiple side entry agitators on blend time and the effect of viscosity (i.e., lower Reynolds numbers) on blend time.
Spatial Variation of the Precipitation Chemistry in the Thrace Region of Turkey
Authors: Şaylan Levent , Çaldağ Barış , Bakanoğulları Fatih , Toros Hüseyin , Yazgan Mustafa , Şen Orhan , Özkoca Yunus 
Published: May 2011

AbstractPollutants affect not only the environment in which they originate since they are also transported by air currents to other locations. For this reason, air pollution is a global problem for all countries and the air and water quality need to be monitored carefully. More information on precipitation chemistry is required to determine the source of pollution as well as its effects on the ecosystems. In this study, precipitation chemistry has been analyzed for the first time by using simple bulk collectors located at four different sites in Northwest Turkey for a period of two years. About 650 sequential rainwater samples were collected and analyzed for pH, electrical conductivity, anions such as ${\rm SO}_{{\rm 4}}^{{\rm 2}{-} } $, ${\rm NO}_{{\rm 3}}^{{-} } $, Cl−, and cations such as Na+, K+, Mg2+, Ca2+, and ${\rm NH}_{{\rm 4}}^{{\rm + }} $. The selected sites were under the effect of different environmental factors. Our results showed that the highest ${\rm SO}_{{\rm 4}}^{{\rm 2}{-} } $ and ${\rm NO}_{{\rm 3}}^{{-} } $ concentrations were measured in the Northwest of the research area. Additionally, it has been found that Ca2+ ions are abundant within all rainwater samples.
Rhizofiltration of a Heavy Metal (Lead) Containing Wastewater Using the Wetland Plant Carex pendula
Authors: Yadav Brijesh K. , Siebel Maarten A. , van Bruggen Johan J. A. 
Published: May 2011

AbstractRhizofiltration is a subset technique of phytoremediation which refers to the approach of using plant biomass for removing contaminants, primarily toxic metals, from polluted water. The effective implementation of this in situ remediation technology requires experimental as well as conceptual insight of plant–water interactions that control the extraction of targeted metal from polluted water resources. Therefore, pot and simulation experiments are used in this study to investigate the rhizofiltration of a lead containing wastewater using plants of Carex pendula, a common wetland plant found in Europe. The metal contaminant extraction along with plant growth and water uptake rates from a wastewater having varying Pb concentration is studied experimentally for 2 wk. The temporal distribution of the metal concentration in the wastewater and the accumulated metal in different compartments of C. pendula at the end are analyzed using atomic absorption spectrometry. Parameters of the metal uptake kinetics are deduced experimentally for predicting the metal removal by root biomass. Further, mass balance equations coupled with the characterized metal uptake kinetics are used for simulating the metal partitioning from the wastewater to its accumulation in the plant biomass. The simulated metal content in wastewater and plant biomass is compared with the observed data showing a good agreement with the later. Results show that C. pendula accumulates considerable amounts of lead, particularly in root biomass, and can be considered for the cleanup of lead contaminated wastewaters in combination with proper biomass disposal alternatives. Also, the findings can be used for performing further non‐hydroponics experiment to mimic the real wetland conditions more closely.
Chemistry and Biological Activity of Platinum Amidine Complexes
Authors: Michelin Rino A. , Sgarbossa Paolo , Mazzega Sbovata Silvia , Gandin Valentina , Marzano Cristina , Bertani Roberta 
Published: May 2011

AbstractPlatinum amidine complexes represent a new class of potential antitumor drugs that contain the imino moiety HNC(sp2) bonded to the platinum center. They can be related to the iminoether derivatives, which were recently shown to be the first PtII compounds with a trans configuration endowed with anticancer activity. The chemical and biological properties of platinum amidine complexes, and more generally of platinum imino derivatives, can be rationally modified through suitable synthetic procedures with the aim of improving their cytotoxicity and antitumor activity. The addition of protic nucleophiles to nitriles coordinated to platinum in various oxidation states can offer a wide variety of complexes with chemical, structural, and physical properties specifically tuned for a more efficacious biological response.
Numerical Measure of a Complex Matrix
Authors: Gallay Thierry , Serre Denis 
Published: May 2011

AbstractWe introduce a natural probability measure over the numerical range of a complex matrix A ∈ Mn(
\input amssym $\Bbb C$). This numerical measure μA can be defined as the law of the random variable 〈AX, X〉 ∈ \input amssym $\Bbb C$
when the vector X ∈ \input amssym $\Bbb C$n is uniformly distributed on the unit sphere. If the matrix A is normal, we show that μA has a piecewise polynomial density fA, which can be identified with a multivariate B‐spline. In the general (nonnormal) case, we relate the Radon transform of μA to the spectrum of a family of Hermitian matrices, and we deduce an explicit representation formula for the numerical density that is appropriate for theoretical and computational purposes. As an application, we show that the density fA is polynomial in some regions of the complex plane that can be characterized geometrically, and we recover some known results about lacunae of symmetric hyperbolic systems in 2 + 1 dimensions. Finally, we prove under general assumptions that the numerical measure of a matrix A ∈ Mn (\input amssym $\Bbb C$) concentrates to a Dirac mass as the size n goes to infinity. © 2011 Wiley Periodicals, Inc.
A new frequency‐uniform coercive boundary integral equation for acoustic scattering
Authors: Spence Euan A. , Chandler‐Wilde Simon N. , Graham Ivan G. , Smyshlyaev Valery P. 
Published: May 2011

AbstractA new boundary integral operator is introduced for the solution of the soundsoft acoustic scattering problem, i.e., for the exterior problem for the Helmholtz equation with Dirichlet boundary conditions. We prove that this integral operator is coercive in L2(Γ) (where Γ is the surface of the scatterer) for all Lipschitz star‐shaped domains. Moreover, the coercivity is uniform in the wavenumber k = ω/c, where ω is the frequency and c is the speed of sound. The new boundary integral operator, which we call the “star‐combined” potential operator, is a slight modification of the standard combined potential operator, and is shown to be as easy to implement as the standard one. Additionally, to the authors' knowledge, it is the only second‐kind integral operator for which convergence of the Galerkin method in L2(Γ) is proved without smoothness assumptions on Γ except that it is Lipschitz. The coercivity of the star‐combined operator implies frequency‐explicit error bounds for the Galerkin method for any approximation space. In particular, these error estimates apply to several hybrid asymptoticnumerical methods developed recently that provide robust approximations in the high‐frequency case. The proof of coercivity of the star‐combined operator critically relies on an identity first introduced by Morawetz and Ludwig in 1968, supplemented further by more recent harmonic analysis techniques for Lipschitz domains. © 2011 Wiley Periodicals, Inc.