bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Exhaustion of CD4+ T Lymphocytes during Primary Cytomegalovirus Infection
Authors: Antoine Pierre , Olislagers Véronique , Huygens Ariane , Lecomte Sandra , Liesnard Corinne , Donner Catherine , Marchant Arnaud
Published: August 2012

Human CMV establishes lifelong persistence after primary infection. Chronic CMV infection is associated with intermittent viral reactivation inducing high frequencies of CD4+ T lymphocytes with potent antiviral and helper properties. Primary CMV infection is characterized by an intense viral replication lasting for several months. The impact of this prolonged exposure to high Ag loads on the functionality of CD4+ T cells remains incompletely understood. In pregnant women with primary CMV infection, we observed that CMV-specific CD4+ T lymphocytes had a decreased capacity to proliferate and to produce IL-2. A very large proportion of CMV-specific CD4+ T cells had downregulated the expression of CD28, a costimulatory molecule centrally involved in the production of IL-2. Unexpectedly, both CD28− and CD28+CD4+ T cells produced low levels of IL-2. This defective production of IL-2 was part of a larger downregulation of cytokine production. Indeed, CMV-specific CD4+ T cells produced lower amounts of IFN-γ and TNF-α and showed lower functional avidity during primary as compared with chronic infection. Increased programmed death-1 expression was observed in CD28+ CMV-specific CD4+ T cells, and programmed death-1 inhibition increased proliferative responses. These results indicate that primary CMV infection is associated with the exhaustion of CMV-specific CD4+ T cells displaying low functional avidity for viral Ags.
Noncovalent Assembly of Anti-Dendritic Cell Antibodies and Antigens for Evoking Immune Responses In Vitro and In Vivo
Authors: Flamar Anne-Laure , Zurawski Sandra , Scholz Felix , Gayet Ingrid , Ni Ling , Li Xiao-Hua , Klechevsky Eynav , Quinn John , Oh SangKon , Kaplan Daniel H. , Banchereau Jacques , Zurawski Gerard
Published: August 2012

Targeting of Ags directly to dendritic cells (DCs) through anti-DC receptor Ab fused to Ag proteins is a promising approach to vaccine development. However, not all Ags can be expressed as a rAb directly fused to a protein Ag. In this study, we show that noncovalent assembly of Ab–Ag complexes, mediated by interaction between dockerin and cohesin domains from cellulose-degrading bacteria, can greatly expand the range of Ags for this DC-targeting vaccine technology. rAbs with a dockerin domain fused to the rAb H chain C terminus are efficiently secreted by mammalian cells, and many Ags not secreted as rAb fusion proteins are readily expressed as cohesin directly fused to Ag either via secretion from mammalian cells or as soluble cytoplasmic Escherichia coli products. These form very stable and homogeneous complexes with rAb fused to dockerin. In vitro, these complexes can efficiently bind to human DC receptors followed by presentation to Ag-specific CD4+ and CD8+ T cells. Low doses of the HA1 subunit of influenza hemagglutinin conjugated through this means to anti-Langerin rAbs elicited Flu HA1-specific Ab and T cell responses in mice. Thus, the noncovalent assembly of rAb and Ag through dockerin and cohesin interaction provides a useful modular strategy for development and testing of prototype vaccines for elicitation of Ag-specific T and B cell responses, particularly when direct rAb fusions to Ag cannot be expressed.
Cutting Edge: IL-10–Mediated Tristetraprolin Induction Is Part of a Feedback Loop That Controls Macrophage STAT3 Activation and Cytokine Production
Authors: Gaba Anthony , Grivennikov Sergei I. , Do Mahn Vu , Stumpo Deborah J. , Blackshear Perry J. , Karin Michael
Published: August 2012

In activated macrophages, the anti-inflammatory cytokine IL-10 inhibits expression of molecules that propagate inflammation in a manner that depends on transcription factor STAT3. Expression of IL-10 is regulated posttranscriptionally by the RNA-binding protein tristetraprolin (TTP), which destabilizes IL-10 mRNA in activated macrophages. Using LPS-activated bone marrow-derived murine macrophages, we demonstrate that TTP is a negative regulator of the IL-10/STAT3 anti-inflammatory response. LPS-stimulated TTP-deficient macrophages overproduced IL-10, contained increased amounts of activated STAT3, and showed reduced expression of inflammatory cytokines, including cytokines encoded by TTP target mRNAs. Thus, in LPS-stimulated TTP-deficient macrophages, increased IL-10/STAT3 anti-inflammatory control was dominant over the mRNA stabilization of specific TTP targets. The TTP gene promoter contains a conserved STAT3 binding site, and IL-10 induces STAT3 recruitment to this site. Correspondingly, STAT3 was required for efficient IL-10–induced TTP expression. Hence, by inducing TTP expression, STAT3 activates a negative regulatory loop that controls the IL-10/STAT3 anti-inflammatory response.
Shaping of Human Germline IgH Repertoires Revealed by Deep Sequencing
Authors: Larimore Kevin , McCormick Michael W. , Robins Harlan S. , Greenberg Philip D.
Published: August 2012

To understand better how selection processes balance the benefits of Ig repertoire diversity with the risks of autoreactivity and nonfunctionality of highly variable IgH CDR3s, we collected millions of rearranged germline IgH CDR3 sequences by deep sequencing of DNA from mature human naive B cells purified from four individuals and analyzed the data with computational methods. Long HCDR3 regions, often components of HIV-neutralizing Abs, appear to derive not only from incorporation of long D genes and insertion of large N regions but also by usage of multiple D gene segments in tandem. However, comparison of productive and out-of-frame IgH rearrangements revealed a selection bias against long HCDR3 loops, suggesting these may be disproportionately either poorly functional or autoreactive. Our data suggest that developmental selection removes HCDR3 loops containing patches of hydrophobicity, which are commonly found in some auto-antibodies, and at least 69% of the initial productive IgH rearrangements are removed from the repertoire during B cell development. Additionally, we have demonstrated the potential utility of this new technology for vaccine development with the identification in all four individuals of related candidate germline IgH precursors of the HIV-neutralizing Ab 4E10.
Simulation of nitrate, sulfate, and ammonium aerosols over the United States
Authors: Walker J. M. , Seinfeld J. H. , Clarisse L. , Coheur P.-F. , Clerbaux C. , Van Damme M.
Published: August 2012

Abstract. Atmospheric concentrations of inorganic gases and aerosols (nitrate, sulfate, and ammonium) are simulated for 2009 over the United States using the chemical transport model GEOS-Chem. This work is motivated, in part, by the inability of previous modeling studies to reproduce observed high nitrate aerosol concentrations in California. Nitrate aerosol concentrations over most of the US are over-predicted relative to Interagency Monitoring of Protected Visual Environments (IMPROVE) and Clean Air Status and Trends Network (CASTNET) data. In California, on the other hand, nitrate and ammonium are under-predicted as compared to California Air Resources Board (CARB) measurements. Over-prediction of nitrate in the East and Midwest is consistent with results of recent studies, which have suggested that nighttime nitric acid formation by heterogeneous hydrolysis of N2O5 is over-predicted with current values of the N2O5 uptake coefficient, γ, onto aerosols. Accordingly, the value of γ is reduced here by a factor of 10. Despite this, predicted nitrate levels in the US Midwest remain higher than those measured and over-prediction of nitrate in this region remains to be explained. Data from the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp-A satellite indicate the presence of a strong ammonia maximum in central and southern California that is not present in the simulations, which are based on the EPA National Emissions Inventory (NEI) NH3 emission inventory. In order to predict ammonia columns similar to the satellite measurements in the San Joaquin Valley, CA and Riverside, CA, the current ammonia emission inventory in California would need to be increased substantially. Based on the sensitivity of ammonium nitrate formation to the availability of ammonia, the present results suggest that under-prediction of ammonia emissions is likely the main cause for the under-prediction of nitrate aerosol in California.
Response of Nodularia spumigena to pCO2 – Part 1: Growth, production and nitrogen cycling
Authors: Wannicke N. , Endres S. , Engel A. , Grossart H.-P. , Nausch M. , Unger J. , Voss M.
Published: August 2012

Abstract. Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2) concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C) and dinitrogen (N2) fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 μatm), mid (median 353 μatm), and high (median 548 μatm) CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2) and 40 ± 25% (mid vs. high pCO2), as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low) and 44% (high vs. mid) at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP) was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the Baltic Sea are discussed.
Assessing ecological land use and water demand of river systems: a case study in Luanhe River, North China
Authors: Yan D. H. , Wang G. , Wang H. , Qin T. L.
Published: August 2012

Abstract. Economic and social development has greatly increased ecological water demand and modified land use of river systems worldwide, causing overall degradation of many of these systems. In this study, theoretical and technical frameworks for regionalization on the eco-environmental function of river systems are formulated and applied to the Luanhe River system. Based on its eco-environmental functions, this river can be regionalized into four types of first-class functional areas: ecological preservation areas, habitat restoration areas, ecological buffer areas and development and utilization areas. Considering the overall eco-environmental functions, we assessed the ecological land use of the Luanhe River system. The total area of basic ecological land use is 876.98 km2; the restrictive ecological land use is 1745.52 km2; ecological land use of the river system returned from farmland is 284.25 km2; and that returned from construction land is 17.35 km2. The average minimum ecological flow of mainstreams in upper and middle reaches of the Luanhe River is 4.896 m3 s−1 based on the habitat method. And the recommended minimum and suitable annual ecological water demand of channels in the lower reaches are 391 million m3 and 819.5 million m3, respectively. The evaporation and seepage consumption and vegetation consumption in riparian zones of the Luanhe River system are approximately 132.6 million m3 and 145.3 million m3 per year, respectively. Our results suggest that is crucial to regulate the instream ecological water use of the Luanhe River's mainstream starting from the Panjiakou-Daheiting Reservoir system. We recommend accelerating ecological land-use planning and strengthening the regulation of ecological water use on this river system focusing on important lower reaches under the condition of competitive water demand.
Streamflow response of a small forested catchment on different time scales
Authors: Zabaleta A. , Antigüedad I.
Published: August 2012

Abstract. The hydrological response of a catchment to rainfall on different time scales is result of a complex system involving a range of physical processes which may operate simultaneously and have different spatial and temporal influences. This paper presents the analysis of streamflow response of a small humid-temperate catchment (Aixola, 4.8 km2) in the Basque Country on different time scales and discusses the role of the controlling factors. Firstly, daily time series analysis was used to establish a hypothesis on the general functioning of the catchment through the relationship between precipitation and discharge on an annual and multi-annual scale (2003–2008). Second, rainfall-runoff relationships and relationships among several hydrological variables, including catchment antecedent conditions, were explored at the event scale (222 events) to check and improve the hypothesis. Finally, the evolution of electrical conductivity (EC) during some of the monitored storm events (28 events) was examined to identify the time-origin of waters. Quick response of the catchment to almost all the rainfall events as well as a considerable regulation capacity was deduced from the correlation and spectral analyses. These results agree with runoff event scale data analysis; however the event analysis revealed the non-linearity of the system, as antecedent conditions play a significant role in this catchment. Further, analysis at the event scale made possible to clarify factors controlling (precipitation, precipitation intensity and initial discharge) the different aspects of the runoff response (runoff coefficient and discharge increase) for this catchment. Finally, the evolution of EC of the waters enabled the time origin (event or pre-event waters) of the quickflow to be established; specifically, the conductivity showed that pre-event waters usually represent a high percentage of the total discharge during runoff peaks. The importance of soil waters in the catchment is being studied more deeply.
There is Beauty Here, Too:
Authors: Poulakos John , Crick Nathan
Published: August 2012

In Aristotle's biological treatise, On the Parts of Animals, one finds a rare and unexpected burst of rhetorical eloquence. While justifying the study of “less valued animals,” he erupts into praise for the study of all natural phenomena and condemns the small-mindedness of those who trivialize its worth. Without equal in Aristotle's remaining works for its rhetorical quality, it reveals the otherwise coolheaded researcher as a passionate seeker of truth and an unabashed lover of natural beauty. For Aristotle, rhetoric not only discloses the truth (aletheia) of appearances by refuting counterarguments and defending one's claims within agonistic forums; rhetoric also defends and advances whole fields of study on the promise on wonder (thaumazein). By examining Aristotle's example in practice, this article seeks to elucidate a notion of the rhetoric for inquiry that calls lovers of wisdom to the empirical study of nature.
Palladium‐Catalyzed CC Coupling of Aryl Halides with Isocyanides: An Alternative Method for the Stereoselective Synthesis of (3E)‐(Imino)isoindolin‐1‐ones and (3E)‐(Imino)thiaisoindoline 1,1‐Dioxides
Authors: Liu Bifu , Li Yibiao , Jiang Huanfeng , Yin Meizhou , Huang Huawen
Published: August 2012

A palladium‐catalyzed, one‐pot cyclization reaction to construct (3E)‐(imino)isoindolin‐1‐ones and (3E)‐(imino)thiaisoindoline 1,1‐dioxides by introducing ortho‐reactive functional groups on aryl halides is reported. Under optimal conditions, the cyclization reaction afforded the corresponding products in good to excellent yields (up to 93%) with high stereoselectivity. Notably, this transformation successfully extends its application for the synthesis of phenanthridines and dibenzooxazepines. This new synthetic protocol not only extends the application platform for palladium‐catalyzed CC coupling of aryl halides with isocyanides, but also opens atom‐economic and step‐economic synthetic routes for nitrogen‐containing heterocyclic compounds with wide functional group compatibility.
Mild and High‐Yielding Molybdenum(VI) Dichloride Dioxide‐Catalyzed Formation of Mono‐, Di‐, Tri‐, and Tetracarbamates from Alcohols and Aromatic or Aliphatic Isocyanates
Authors: Stock Christian , Brückner Reinhard
Published: August 2012

Both molybdenum(VI) dichloride dioxide (MoO2Cl2) and its dimethylformamide (DMF) complex catalyze the addition of alcohols to isocyanates giving carbamates. Most additions proceeded to completion at room temperature within 20 min using as little as 0.1 mol% of the catalyst when working on a 1‐mmol scale or just 100 ppm working on a 20‐mmol scale. Sterically encumbered substrates reacted to completion when 1 mol% of the catalyst was employed. Diols, triols, and tetraols reacted with monoisocyanates likewise, as did monofunctional alcohols and diisocyanates. These pairings furnished di‐, tri‐, tetra‐, and dicarbamates, respectively. Reactants, which were poorly soluble in CH2Cl2 at room temperature required elevating the temperature and possibly choosing a higher‐boiling solvent (ClCH2CH2Cl, DMF) as well. Additions of diols to diisocyanates were feasible, too, giving polycarbamates as we presume.
Growth charts for 22q11 deletion syndrome
Authors: Tarquinio Daniel C. , Jones Marilyn C. , Jones Kenneth Lyons , Bird Lynne M.
Published: August 2012

The purpose of this work was to create growth curves specific to the 22q11.2 deletion syndrome. Growth parameters on 188 patients (86 females, 102 males) followed by a group of three dysmorphologists were collected by retrospective chart review. Growth charts for body mass, length/height, and head circumference were generated using a semi‐parametric model with goodness‐of‐fit tests. The resulting charts show that between 25 and 50% of children with 22q11.2 deletion syndrome fall below the 2nd centile for the normal population for all growth parameters. Establishing norms of growth for 22q11.2 deletion syndrome allows the clinician to identify and investigate those children who deviate substantially from the growth profile of this condition. © 2012 Wiley Periodicals, Inc.
IMPAD1 mutations in two Catel‐Manzke like patients
Authors: Nizon Mathilde , Alanay Yasemin , Tuysuz Beyhan , Kiper Pelin Ozlem Simsek , Geneviève David , Sillence David , Huber Celine , Munnich Arnold , Cormier‐Daire Prof. Valérie
Published: August 2012

Catel–Manzke syndrome is characterized by hyperphalangism with bilateral deviation of the index fingers and micrognathia with or without cleft palate. Some atypical patients present with additional malformations. No molecular basis is yet available. Most patients have an unremarkable family history but autosomal recessive inheritance has been recently suggested in a consanguineous family with recurrence in sibs. Catel–Manzke syndrome has overlapping features with Desbuquois dysplasia type 1 due to CANT1 (calcium‐activated nucleotidase 1) mutations and also with “chondrodysplasia with joint dislocations, gPAPP type” due to IMPAD1 (Inositol Monophosphatase Domain containing 1) mutations recently reported in four patients, all characterized by short stature, joint dislocations, brachydactyly and cleft palate. The aim of our study was to screen CANT1 and IMPAD1 in Catel–Manzke patients. Three patients were diagnosed as classical Catel–Manzke syndrome and two as Catel–Manzke like patients, based on the presence of additional features. We identified two homozygous loss‐of‐function IMPAD1 mutations in the two Catel–Manzke like patients (p.Arg187X and p.Ser108ArgfsX48). The phenotype was characterized by severe growth retardation with short and abnormal extremities, cleft palate with micrognathia and knee hyperlaxity. Radiographs of hands and feet revealed numerous accessory bones with abnormally shaped phalanges and carpal synostosis. Based on this report, we concluded that IMPAD1 should be screened for patients with Catel–Manzke and additional features. © 2012 Wiley Periodicals, Inc.
IRF6 is a risk factor for nonsyndromic cleft lip in the Brazilian population
Authors: Brito Luciano A. , Bassi Camila F.S. , Masotti Cibele , Malcher Carolina , Rocha Kátia M. , Schlesinger David , Bueno Daniela F. , Cruz Lucas A. , Barbara Ligia K. , Bertola Débora R. , Meyer Diogo , Franco Diogo , Alonso Nivaldo , Passos‐Bueno Maria Rita
Published: August 2012

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a complex disorder with a worldwide incidence estimated at 1:700. Among the putative susceptibility loci, theIRF6gene and a region at 8q24.21 have been corroborated in different populations. To test the role ofIRF6in NSCL/P predisposition in the Brazilian population, we conducted a structured association study with the SNPs rs642961 and rs590223, respectively, located at 5′ and 3′ of theIRF6gene and not in strong linkage disequilibrium (LD), in patients from five different Brazilian locations. We also evaluated the effect of these SNPs inIRF6expression in mesenchymal stem cells (MSC). We observed association between rs642961 and cleft lip only (CLO) (P = 0.009; odds ratio (OR) for AA genotype = 1.83 [95% Confidence interval (CI), 0.64–5.31]; OR for AG genotype = 1.72 [95% CI, 1.03–2.84]). This association seems to be driven by the affected patients from Barbalha, a location which presents the highest heritability estimate (H2 = 0.85), and the A allele at rs642961 is acting through a dominant model. No association was detected for the SNP rs590223. We did not find any correlation between expression levels and genotypes of the two loci, and it is possible that these SNPs have a functional role in some specific period of embryogenesis. © 2012 Wiley Periodicals, Inc.
Selective Synthesis and Structural Confirmation of 1,3‐Oxazines and Schiff Bases with Controllable Substitution Patterns
Authors: Sundaramoorthy Karthikeyan Natesan , Ramachandran Gunasekar , Rathore Ravindranath S , Iyer Sathiyanarayanan Kulathu
Published: August 2012

Selective synthesis of 2,4‐diaryl‐2,3‐dihydro‐3H‐naphtho[1,2‐e]‐1,3‐oxazines and Schiff bases ((E)‐[1‐arylmethyl(benzylideneamino)]naphth‐2‐ols) that contain two identical or two different aryl substituents was achieved through one‐pot synthesis with ammonium acetate. From the proposed mechanism the dual role of ammonium acetate was identified. The synthesized products were characterized by 1H and 13C NMR spectroscopy, as well as FTIR and mass spectrometry. Crystal structures of the 1,3‐oxazines and Schiff base derivatives were examined. A notable feature is the conspicuous absence of strong donors (NH/OH) in any intermolecular hydrogen‐bonding scheme. Instead, packing is characterized by weak intermolecular CH⋅⋅⋅O, CH⋅⋅⋅π and CCl⋅⋅⋅π interactions, which lead to dimeric and zig‐zag one‐dimensional molecular patterns. The oxazine moiety of the tricyclic ring system predominantly adopts a half‐chair conformation. The present Mannich procedure is an environmentally benign and cost‐effective method for the preparation of industrially and pharmaceutically useful heterocyclic scaffolds.
Luminescent Ionic Transition‐Metal Complexes for Light‐Emitting Electrochemical Cells
Authors: Costa Rubén D. , Ortí Enrique , Bolink Henk J. , Monti Filippo , Accorsi Gianluca , Armaroli Nicola
Published: August 2012

Higher efficiency in the end‐use of energy requires substantial progress in lighting concepts. All the technologies under development are based on solid‐state electroluminescent materials and belong to the general area of solid‐state lighting (SSL). The two main technologies being developed in SSL are light‐emitting diodes (LEDs) and organic light‐emitting diodes (OLEDs), but in recent years, light‐emitting electrochemical cells (LECs) have emerged as an alternative option. The luminescent materials in LECs are either luminescent polymers together with ionic salts or ionic species, such as ionic transition‐metal complexes (iTMCs). Cyclometalated complexes of IrIII are by far the most utilized class of iTMCs in LECs. Herein, we show how these complexes can be prepared and discuss their unique electronic, photophysical, and photochemical properties. Finally, the progress in the performance of iTMCs based LECs, in terms of turn‐on time, stability, efficiency, and color is presented.
CH Bond Functionalization: Emerging Synthetic Tools for Natural Products and Pharmaceuticals
Authors: Yamaguchi Junichiro , Yamaguchi Atsushi D. , Itami Kenichiro
Published: August 2012

The direct functionalization of CH bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon–carbon and carbon–heteroatom bonds. This Review provides an overview of CH bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.
Microstructure and properties of branched polyethylene: Application of a three‐phase structural model
Authors: Martín S. , Expósito M. T. , Vega J. F. , Martínez‐Salazar J.
Published: August 2012

A combined study of microstructure and mechanical properties for a series of single‐site metallocene ethylene/1‐hexene copolymers is presented. The analysis of the results focuses on the effect of branching, which in turn modulates crystallinity and density, on the values of the elastic modulus obtained in tensile‐deformation experiments. An extensive literature review is done in order to compare our own results with previous studies. The typical variation found in the elastic modulus is discussed in terms of the existence of a rigid amorphous phase. This rigid phase controls the macroscopic mechanical behavior of the materials, giving rise to an increase of the elastic modulus as the crystallinity does. Mechanical coupling models for heterogeneous systems are applied in order to describe the experimental results of the elastic modulus as a function of the variation of three different phase fractions, i.e., crystalline, rigid amorphous (or interfacial), and mobile amorphous. The phase fraction values obtained from the analysis of the mechanical properties are in qualitative agreement to those found experimentally in our group by Raman infrared spectroscopy and from the literature by positron annihilation lifetime spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Poly(lactic acid)/halloysite nanotubes nanocomposites: Structure, thermal, and mechanical properties as a function of halloysite treatment
Authors: Prashantha Kalappa , Lecouvet Benoît , Sclavons Michel , Lacrampe Marie France , Krawczak Patricia
Published: August 2012

Poly(lactic acid) (PLA)/halloysite nanotubes (HNT) nanocomposites were prepared by melt extrusion using a masterbatch dilution process. Effect of addition of both unmodified halloysites (HNT) and quaternary ammonium salt treated halloysites (m‐HNT) was investigated at different nanofiller contents. A homogeneous distribution/dispersion of halloysites in the PLA matrix is obtained for both unmodified and modified nanotubes within the studied composition range. The nucleating effect of halloysites, resulting in a limited increase of degree of crystallinity, is more pronounced in the case of m‐HNT. Besides, the rigidity, tensile, flexural, and impact resistances of PLA significantly increase on addition of halloysites, the property improvement being higher for m‐HNT than for HNT. Interestingly, there is no significant embrittlement (almost constant elongation at break). Based on micromechanical models, this superior reinforcement efficiency of m‐HNT was ascribed to the better interfacial compatibility induced by the modification of the nanotube surface. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Modification and characterization of polyacrylonitrile fiber by chelating ligand for preconcentration and determination of neodymium ion in biological and environmental samples
Authors: Sadeghi Hayedeh Bagheri , Panahi Homayon Ahmad , Abdouss Majid , Esmaiilpour Behnaz , Nezhati Mahshid Nikpour , Moniri Elham , Azizi Zahra
Published: August 2012

In this study a chelating fiber containing iminodiacetic acid was prepared via the stepwise modification of acrylic fibers, polyacrylonitrile. The resulting modified fiber has been characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and scanning electron microscopy. Then polyacrylonitrile‐ iminodiacetic acid was applied for preconcentration and determination of trace Nd(III) ion from human biological fluid and environmental water samples with inductively coupled plasma – atomic emission spectroscopy. The optimum pH value for sorption of the metal ion was 6. The sorption capacity of functionalized resin is 8.9 mg g−1. A recovery of 100% was obtained with preconcentration factor 10 for the Nd(III) with 0.5 M nitric acid as eluting agent. The profile of Nd(III) uptake on this sorbent reflects good accessibility of the chelating sites in the modified polyacrylonitrile. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Nd(III) on modified fiber were analyzed by Langmuir models. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Conductive performances of elastomeric electrolytes based on maleic anhydride‐g‐poly(1, 2‐butadiene) grafting polyethylene glycol 400 and LiClO4
Authors: Wang Jinwei , Zhao Ge
Published: August 2012

Elastomeric electrolyte films consisting of maleic anhydride‐g‐poly (1, 2‐butadiene) (MAPB) grafting polyethylene glycol 400 (PEG400) as matrix and LiClO4 as alkali salt at the mole ratio of [O]: [Li+] at 6, 8, and 10, respectively are prepared. An equivalent circuit is proposed based on the electronic impedance spectroscopy plots by using the metal/electrolyte film/metal model, the simulant plots are found matched well with the tested plots, and the conductivity variations with salt concentrations and temperatures are calculated accordingly. The film with the mole ratio of [O]: [Li+] at 8:1 exhibits higher conductivity at room temperature, due to its relatively stronger dissociation of oxygen atom to LiClO4 as supported by the FTIR spectroscopy. Their conductivity dependent on temperatures obeys the Arrhenius equation from 303 to 363 K, while it keeps almost unchanged at higher temperatures; these changes are found associate with the strong complexation of oxygen atom with Li+ and the state transference of MAPB elastomer as observed by the DSC analysis. Besides, these films are still thermally stable at around 200°C as observed by the TGA analysis and may be promising solid polymer electrolytes with high stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
External coronary artery compression due to prosthetic valve bacterial endocarditis
Authors: Harinstein Matthew E. , Marroquin Oscar C.
Published: August 2012

Acute coronary syndromes in the setting of infective endocarditis may be the result of coronary compression secondary to periannular aortic valve complications, coronary embolism, obstruction of the coronary ostium due to a large vegetation, coronary atherosclerosis, and severe aortic insufficiency. External coronary artery compression as a result of infective endocarditis is a rare and lethal finding with few reported cases available in the medical literature. We present a rare occurrence of an acute coronary syndrome occurring in the setting of a bioprosthetic aortic valve abscess in which there was no complete coronary occlusion visualized and given the patient's recent unremarkable catheterization and findings of diffuse tapering of the proximal left coronary system, the most likely etiology was external compression secondary to the known aortic root abscess, which caused myocardial ischemia, and was confirmed during surgery. Although uncommon, external compression should be considered in the differential diagnosis of acute coronary syndrome in this setting and coronary angiography can be diagnostic of this entity.© 2012 Wiley Periodicals, Inc.
Safety and performance of the spider™ patent foramen ovale occluder
Authors: Edwards‐Lehr Tina , Franke Jennifer , Bertog Stefan C. , Bäcker Christina , Wunderlich Nina , Hofmann Ilona , Wilson Neil , Piechaud Jean‐François , Sievert Horst
Published: August 2012

Objectives

The aim of this clinical trial was to assess safety, efficacy, and technical handling of a novel ceramic‐coated double‐disc patent foramen ovale (PFO) occluder.

Background

Though percutaneous PFO closure is performed with increasing frequency worldwide, certain risks such as thrombus formation and incomplete endothelialization remain. The Spider™ PFO occluder was designed to minimize these risks.

Methods

The Spider™ PFO occluder is a self‐expandable double‐disc device with a ceramic coated nitinol wire mesh and an integrated expanded polytetrafluoroethylene (ePTFE) membrane on the right atrial side and ceramic coated nitinol anchors and ePTFE patch on the left atrial side. Study patient assessments were conducted at baseline, periprocedure, and discharge and at 1‐, 6‐ and 12‐month follow‐up.

Results

Fifty‐one patients (mean age 52 ± 14 years; 63% male) were enrolled in the prospective, multicenter clinical trial. Implantation was successful in all patients. Mean procedural time was 30.0 ± 8.6 min. No periprocedural or in‐hospital complications occurred. Four patients (8%) had paroxysmal atrial fibrillation (AF) at 1‐month follow‐up. Otherwise, no procedure or device related adverse events occurred. Importantly, there were no recurrent embolic events. At 1‐month follow‐up 63% (32/51) of patients had no residual shunt with contrast transesophageal echocardiography during Valsalva maneuver. Of all patients who underwent 6‐month echo follow‐up to date, 78% (39/50) had no residual shunt during Valsalva maneuver.

Conclusion

Initial results with the novel Spider™ PFO occluder show that the device is safe and easy to use for percutaneous closure of PFO. The overall complication rate was low. The rate of AF needs further investigation. © 2012 Wiley Periodicals, Inc.
Feasibility and utility of pre‐procedure ultrasound imaging of the arm to facilitate transradial coronary diagnostic and interventional procedures (PRIMAFACIE‐TRI)
Authors: Kumar Chugh Sanjay , Chugh Sunita , Chugh Yashasvi , Rao Sunil V.
Published: August 2012

Objectives

To assess feasibility and utility of imaging of both arms using ultrasound to facilitate transradial (TR) and transulnar (TU) coronary angiograms (CA) and intervention.

Background

Despite well recognized advantages, transradial approach (TRA) has challenges that reduce procedural success including small arterial size, anatomical variations, and anomalies of radial artery (RA). The utility of routine pre‐procedural ultrasound of the arm arteries (PPUAA) in facilitating TRA has not been previously studied.

Methods

To determine the role of PPUAA, we performed a single center registry of consecutive patients undergoing diagnostic and interventional procedures between 2006 and 2011. All patients underwent PPUAA of the right and left radial, ulnar (UA), as well as the brachial arteries (BA) in the antecubital fossa using a linear probe. End‐points assessed included the incidence and correlates of arterial sizes, vascular anomalies, procedure success, and fluoroscopy as well as ultrasound assessment times. RA occlusion rates were studied in the last 10 months of the study period.

Results

Complete data on radial (mean 1.9 mm (male);1.7 mm (female)) and ulnar artery size (mean 1.8 mm (male); 1.6 mm (female)) and data on brachial branching anatomy were available in 2,344 patients; 1,872 of whom underwent a TR or TU procedure. The mean time to perform bilateral PPUAA was 6.4 min ± 1.8 min. The incidence of arterial abnormalities was 9.8% in PPUAA. Procedure success was 98.7% for CA and 97.5% for percutaneous coronary intervention. Outcomes were better in this cohort compared with remaining 3,781 patients in whom PPUAA data were not available.

Conclusion

This single center prospective registry shows that PPUAA is feasible, requires minimum time, and provides anatomical information that may improve procedure success while reducing patient discomfort, arterial spasm, and fluoroscopy time. These findings should be confirmed in a randomized trial. © 2013 Wiley Periodicals, Inc.
Adjunctive thrombus aspiration versus conventional percutaneous coronary intervention in ST‐elevation myocardial infarction
Authors: Kikkert Wouter J. , Claessen Bimmer E. , van Geloven Nan , Baan Jan , Vis Marije M. , Koch Karel T. , Piek Jan J. , Tijssen Jan G.P. , Henriques Jose P.S.
Published: August 2012

Objectives

The objective of this analysis is to determine the effects on mortality of thrombus aspiration during primary percutaneous coronary intervention (PPCI) for ST‐elevation myocardial infarction (STEMI) compared with conventional PCI.

Background

Adjunctive thrombus aspiration in STEMI improves markers of myocardial reperfusion but evidence for improved survival is limited to the TAPAS trial.

Methods

We used data of 3,750 consecutive STEMI patients treated with either conventional PCI or thrombus aspiration between August 1, 2001 and January 1, 2009. For each patient, a propensity score was calculated based on clinical and angiographic characteristics, predicting a patient's probability of having been treated with thrombus aspiration. This propensity score was used in several ways to account for differences between patients treated with and without thrombus aspiration. In our primary analysis, patients treated with thrombus aspiration were matched one‐to‐one with patients treated with conventional PCI on their propensity score (1,391 matched pairs). Kaplan Meier and Cox regression models were used to estimate the influence of treatment on one‐year mortality.

Results

In total, 1,502 patients (40.1%) were treated with thrombus aspiration. In the propensity matched cohort, after one year 7.2% of patients treated with thrombus aspiration had died compared with 9.3% of patients in the control group. The hazard ratio for one‐year mortality in patients treated with thrombus aspiration was 0.76 (95% CI: 0.59–0.99; P = 0.043). The hazard ratio remained materially unaltered and statistically significant in secondary analyses, varying between 0.61 and 0.77.

Conclusion

The routine use of thrombus aspiration was associated with reduced one‐year mortality in this large real‐world patient cohort. These data support the observed survival benefit in the TAPAS trial. © 2012 Wiley Periodicals, Inc.
Off‐label use of percutaneous pulmonary valved stents in the right ventricular outflow tract: Time to rewrite the label?
Authors: Boshoff Derize E. , Cools Bjorn L.M. , Heying Ruth , Troost Els , Kefer Joelle , Budts Werner , Gewillig Marc
Published: August 2012

Introduction

Percutaneous pulmonary valve implantation is now considered feasible and safe. “Native” right ventricular outflow tract (RVOT), small diameter conduits (<16 mm) and relatively large RVOT with a dynamic outflow aneurysm are currently considered off‐label uses. Extending indications creates concerns of safety, ethics, reimbursement, and liability.

Aim of study

To report the safety and feasibility of off‐label application of percutaneous pulmonary valve implantation.

Design

Retrospective analysis of prospectively collected data.

Patients and Methods

Off‐label indications: conduit‐free RVOT or patients with an existing but undersized conduit.

Results

Twenty‐one Melody® valves and two Sapien® valves were successfully implanted in 23 patients (16.9 years; range 6.1–80.5 years). In 22 patients, prestenting was performed 4.8 months (range 0–69.2) before valve implantation (15 covered and 13 bare stents). Stent endothelial ingrowth was allowed for at least 2 months prior to implantation of the percutaneous valve if stent stability or sealing by the covering was presumed to be insufficient. Group 1 patients (n = 8) had a “conduit‐free” RVOT after transannular/infundibular patch and after prestenting underwent percutaneous pulmonary valve implantation (PPVI), with a final RVOT diameter of 21.5 mm (range 16–26 mm). Group 2 patients consisted of two elderly patients with pulmonary valve stenosis and severe RVOT calcifications. Group 3 (n = 13) had an existing conduit (nominal 15.9 ± 3.2 mm; range 10–20 mm). The conduit was augmented from 14.7 ± 3.5 to 20 ± 1.6 mm with PPVI. The RVOT preparation and valve implantations were uneventful.

Conclusions

PPVI is safe and feasible in selected patients with an off‐label indication. Creating an adequate “landing zone” by prestenting makes the procedure safe and predictable. Updating the indications for PPVI should be considered. © 2013 Wiley Periodicals, Inc.
Cause of death after transcatheter aortic valve implantation
Authors: Van Mieghem Nicolas M. , van der Boon Robert M. , Nuis Rutger‐Jan , Schultz Carl , van Geuns Robert‐Jan , Serruys Patrick W. , Kappetein Arie‐Pieter , van Domburg Ron T. , de Jaegere Peter P.
Published: August 2012

Objectives

To evaluate survival and cause of death in a consecutive patient cohort undergoing Transcatheter Aortic Valve implantation (TAVI).

Background

TAVI is a valid treatment option in patients with severe Aortic Stenosis (AS) who are deemed at (very) high operative risk. Because of (non‐)cardiac comorbidities life expectancy in this patient, population is reduced when compared with the general population.

Methods

Consecutive patients with symptomatic aortic stenosis undergoing TAVI between November 2005 and December 2011 were included. (1) Survival status was obtained from the Dutch Civil Registry, (2) cause of death was derived by reviewing hospital charts, and (3) contacting referring physicians and patients' general practitioners.

Results

Two hundred and thirty‐seven consecutive patients were included with an overall all‐cause mortality of 31% at a median follow up of 13 months (IQR 2–24 months). Four patients (1.6%) died < 48 hr of the TAVI procedure, and another 16 patients died up to the 30‐day interval representing an all‐cause 8.4% 30‐day mortality. Between 30 days and 1‐year another 30 patients died. Twenty‐four patients died >1 year post TAVI. The predominant cause of death >48 hr post TAVI was noncardiac. One third of these deaths were due to sepsis/infection, one‐fifth to cancer and stroke in 16%.

Conclusions

In our series of AS patients undergoing TAVI, the cause of death >48 hr post procedure was predominantly noncardiac at every time interval. Mortality was driven by sepsis/infection, cancer, and stroke. Rigorous patient selection may improve outcome after TAVI. © 2013 Wiley Periodicals, Inc.
Synthesis, Structure, and Reactivity of Borole‐Functionalized Ferrocenes
Authors: Braunschweig Holger , Chiu Ching‐Wen , Gamon Daniela , Kaupp Martin , Krummenacher Ivo , Kupfer Thomas , Müller Robert , Radacki Krzysztof
Published: August 2012

Herein, we report on the synthesis of ferrocenylborole [Fc(BC4Ph4)2] featuring two borole moieties in the 1,1′‐positions. The results of NMR and UV/Vis spectroscopy and X‐ray diffraction studies provided conclusive evidence for the enhanced Lewis acidity of the boron centers resulting from the conjugation of two borole fragments. This finding was further validated by the reaction of [Fc(BC4Ph4)2] and the 4‐Me‐NC5H4 adduct of monoborole [Fc(BC4Ph4)], which led to quantitative transfer of the Lewis base. The coordination chemistry of ferrocenylboroles was further studied by examining their reactivity towards several pyridine bases. Accordingly, the strong Lewis acidity of boroles in general was nicely demonstrated by the reaction of [Fc(BC4Ph4)] with 4,4′‐bipyridine. Unlike common borane derivatives such as [FcBMe2], which only forms a 2:1 adduct, we also succeeded in the isolation of a 1:1 Lewis acid/base adduct, with one nitrogen donor of 4,4′‐bipyridine remaining uncoordinated. In addition, the reduction chemistry of ferrocenylboroles [Fc(BC4Ph4)] and [Fc(BC4Ph4)2] has been studied in more detail. Thus, depending on the reducing agent and the reaction stoichiometry, chemical reduction of [Fc(BC4Ph4)] might lead to the migration of the borolediide fragment towards the iron center, affording dianions with either η5‐coordinated C5H4 or η5‐coordinated BC4Ph4 moieties. In contrast, no evidence for borole migration was observed during reduction of bisborole [Fc(BC4Ph4)2], which readily resulted in the formation of the corresponding tetraanion. Finally, our efforts to further enhance the borole ratio in ferrocenylboroles aiming at the synthesis of [Fc(BC4Ph4)4] failed and, instead, generated an uncommon ansa‐ferrocene containing two borole fragments in the 1,1′‐positions and a B2C4 ansa‐bridge.
Viewing and Inducing Symmetry Breaking at the Single‐Molecule Limit
Authors: Tierney Heather L. , Jewell April D. , Baber Ashleigh E. , Iski Erin V. , Sykes E. Charles H.
Published: August 2012

Symmetry breaking by photons, electrons, and molecular interactions lies at the heart of many important problems as varied as the origin of homochiral life to enantioselective drug production. Herein we report a system in which symmetry breaking can be induced and measured in situ at the single‐molecule level using scanning tunneling microscopy. We demonstrate that electrical excitation of a prochiral molecule on an achiral surface produces large enantiomeric excesses in the chiral adsorbed state of up to 39%. The degree of symmetry breaking was monitored as a function of scanning probe tip state, and the results revealed that enantiomeric excesses are correlated with the intrinsic chirality in scanning probe tips themselves, as evidenced by height differences between single molecule enantiomers. While this work has consequences for the study of two‐dimensional chirality, more importantly, it offers a new method for interrogating the coupling of photons, electrons, and combinations of physical fields to achiral starting systems in a reproducible manner. This will allow the mechanism of chirality transfer to be studied in a system in which enantiomeric excesses are quantified accurately by counting individual molecules. Chirality 24:1051–1054, 2012. © 2012 Wiley Periodicals, Inc.
Platform for the Design of Process Control Structures of Dividing Wall Columns
Authors: Buck Christina , Fieg Georg
Published: August 2012

Der Beitrag befasst sich mit dem systematischen Entwurf und Test von Prozessführungskonzepten für Trennwandkolonnen. Es wird eine Entwicklungsplattform präsentiert, die diese Gesamtaufgabe systematisch und weitgehend automatisch löst. Neben der Beschreibung der Bestandteile der Plattform und ihrer Funktionalitäten wird zudem ein praktisches Beispiel gezeigt, das die Anwendbarkeit der Plattform für die Entwicklung eines Prozessführungskonzepts einer Trennwandkolonne im Technikumsmaßstab belegt. Eine erfolgreiche, praktische Validierung des Konzepts rundet die Entwicklungsarbeiten ab.