bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of solvent dielectric properties on the collection of oriented electrospun fibers
Authors: Sun Zaicheng , Deitzel Joseph M. , Knopf Jeff , Chen Xing , Gillespie John W.
Published: January 2012

A simple approach to electrospinning has been developed that enables the collection of polymer, ceramic, and multiphase composite fibers, in quantity, with a high degree of spatial orientation. It has been demonstrated that a careful choice of solvent effectively eliminates the onset of the characteristic “bending” instability that is commonly associated with the electrospinning process. This allows collection of spatially oriented submicron electrospun fibers on a rotating drum without the need for elaborate mechanical or electrostatic manipulation of the electrospinning jet and/or collection target (Deitzel, J. M.; Kleinmeyer, J. D. et al. Polymer 2001, 42, 8163, Zussman, E.; Theron, A.; et al. Appl Phys Lett 2003, 82, 973, and Li, D. Wang, Y. L.; et al. Nano Lett 2003, 3, 1167). Fibers have been electrospun from a series of model polyethylene oxide/CHCl3 solutions with a range of conductivities. The experimental data confirms theoretical predictions that the onset of the bending instability is a function of the available “free” charge in the solution, which in turn is strongly influenced by the dielectric constant of the solvent. The results show that fiber orientation becomes random as the conductivity increases, indicating the need for the surface charge density to exceed a critical threshold in order for the bending instability to initiate. This method has been experimentally demonstrated with other low‐dielectric constant solvents and other common polymer, ceramic, and composite materials. Furthermore, it has been demonstrated that fibers electrospun from these solutions can be mechanically drawn to submicron dimensions (∼ 200–500 nm) by controlling drum speed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of colloidal silica dispersions on the properties of PDMS‐colloidal silica composites
Authors: Sumi Dinkar , Dhanabalan A. , Thimmappa B. H. S. , Krishnamurthy Sriram
Published: February 2012

Polydimethylsiloxane (PDMS) colloidal silica composites prepared with the use of the dispersion of colloidal silica (CS) of similar particle size and distribution in different mediums/solvents are investigated for their rheological, thermal, and mechanical properties. Regardless of the dispersion medium of CS, thermal analysis showed the increased thermal stability of PDMS with the addition of CS. The rheological analysis showed that the composites prepared from CS dispersed in isopropanol (IPA) and CS dispersed in methylethylketone (MEK) showed significant enhancement in viscosity at higher loadings as compare with the composite prepared from the CS dispersed in water and methanol indicating more Filler–polymer interactions. Similarly, the tensile stress–strain curves, hardness, and tear strength displayed significant improvement with PDMS‐CS‐MEK and PDMS‐CS‐IPA composites. The results of this study not only provide the insights of solid–liquid–liquid interface leading to different extent of polymer‐filler interaction, there by the bulk properties, it also helps to minimize the surface treatment steps while preparing the composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and properties of bio‐based thermoplastic polyurethane based on poly (L‐lactic acid) copolymer polydiol
Authors: Zeng Chao , Zhang Nai‐Wen , Ren Jie
Published: January 2012

The goal of this work is the synthesis of a new kind of bio‐based thermoplastic polyurethane (BTPU) based on poly(L‐lactic acid) (PLA) and poly(tetramethylene) glycol (PTMEG) segments via chain‐extension reaction of dihydroxyl terminated (HO‐PLA‐PTMEG‐PLA‐OH) copolymer using hexamethylene diisocyanate (HDI) as a chain extender. Polydiols were synthesized through polycondensation of lactic acid and PTMEG in bulk. The chemical structures and molecular weights of polydiols and BTPUs containing different segment lengths and weight fractions of PLA, were characterized by 1H‐NMR and FTIR. The effects of the structures on the physical properties of BTPUs were studied by means of DSC, SEM, and tensile test; crystallization behavior was characterized by POM. The DSC and SEM results indicate that PLA segment is perfectly compatible with PTMEG segment and the crystallization of BTPU is predominantly caused by PLA segment. Polydiol with lower PLA content shows lower Tg and lower crystallinity. Tensile test shows that the elongation at break of BTPU is above 340% at the composition of PLA/PTMEG = 80/20 (w/w). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterization of photoactive chiral copolymers of (S)‐N‐(1‐phenyl ethyl) methacrylamide and disperse red 1 methacrylate
Authors: Bag Dibyendu S , Alam Sarfaraz
Published: January 2012

In this article, we report the synthesis and characterization of chiral copolymers containing a photoactive azobenzene pendant group. The chiral copolymers of (S)‐N‐(1‐phenyl ethyl) methacrylamide (S‐NPEMAM) and disperse red 1 methacrylate (DR1MA) with two different feed compositions were synthesized by free‐radical polymerization with 2,2′‐azobisisobutyronitrile as an initiator. The purified chiral copolymers, poly[(S)‐N‐(1‐phenyl ethyl) methacrylamide‐co‐disperse red 1 methacrylate], were characterized by Fourier transform infrared spectroscopy, NMR, ultraviolet–visible spectroscopy, and gel permeation chromatography analyses. The photoluminescence and chiroptical properties of the copolymers were evaluated. Induced circular dichroism (CD) was observed in the CD spectra, which arose because of the exciton splitting originated by the cooperative interactions between the pendant azobenzene chromophore of DR1MA and the benzene ring of the chiral monomer. The glass‐transition temperatures of the chiral copolymers were observed to be above 117°C, and the chiral copolymers were thermally stable up to 250°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Novel electromagnetic interference shielding effectiveness in the microwave band of magnetic nitrile butadiene rubber/magnetite nanocomposites
Authors: Al‐Ghamdi A. A. , Al‐Hartomy Omar A. , Al‐Salamy F. , Al‐Ghamdi Attieh A. , El‐Mossalamy E. H. , Abdel Daiem A. M. , El‐Tantawy Farid
Published: January 2012

A novel nitrile butadiene rubber (NBR)/magnetite (Fe3O4) nanocomposite for electromagnetic interference (EMI) shielding at microwave frequency was successfully fabricated. The structural features of as‐synthesized magnetite and NBR/Fe3O4 were examined by X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The number of elastically effective chains, volume fraction of rubber, interparticle distance among conductive sites, polymer–filler interaction, and porosity of the nanocomposites were evaluated. The mechanical properties, including the tensile strength, elongation at break, and hardness, of the composites were measured. The static electrical properties, such as the electrical conductivity, carrier mobility, and number of charge carriers, as a function of magnetite content were evaluated. The interrelation between the electrical conductivity, shielding effectiveness (SE), dielectric constant, and skin depth of the composites are discussed. Finally, the EMI SE versus frequency was tested. The results reveal that an SE of 28–91 dB against EMI in the 1–12 GHz range depended on the loading of the conducting magnetite within the NBR matrix. Accordingly, these nanocomposites may used in the field of microwave absorption devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Binding and recognition ability of molecularly imprinted polymer toward p‐nitrophenol
Authors: An Fu Qiang , Gao Bao Jiao , Feng Xiao Qin
Published: January 2012

p‐Nitrophenol is a hazardous phenolic compound and its separation and determination is very necessary to protect public health and environmental quality. In this article, macromolecule polyethyleneimine (PEI) grafted on the surface of silica particles was crosslinked using p‐nitrophenol as a template and diepoxyalkyl (669) as a crosslinking agent, and molecularly imprinted polymer on the surfaces of silica gel MIP‐PEI/SiO2 was prepared. The binding and recognition ability of MIP‐PEI/SiO2 for p‐nitrophenol were researched using batch and dynamic methods. The experimental results showed that MIP‐PEI/SiO2 had high affinity, specific recognition ability, and excellent selectivity for p‐nitrophenol. The saturated binding amount could reach to 155.5 mg g−1. The selectivity coefficients relative to m‐nitrophenol and chlorophenol were 45.80 and 117.5, respectively. The empirical Freundlich isotherm was found to describe well the equilibrium binding data. pH of sample solution was found to have a strong influence on the binding amount. MIP‐PEI/SiO2 was regenerated easily using diluted hydrochloric acid solution as eluent and MIP‐PEI/SiO2 possesses better reusability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A novel electrospun TPU/PVdF porous fibrous polymer electrolyte for lithium ion batteries
Authors: Wu Na , Jing Bo , Cao Qi , Wang Xianyou , Kuang Hao , Wang Qiang
Published: January 2012

Novel blend‐based gel polymer electrolyte (GPE) films of thermoplastic polyurethane (TPU) and poly(vinylidene fluoride) (PVdF) (denoted as TPU/PVdF) have been prepared by electrospinning. The electrospun thermoplastic polyurethane‐co‐poly (vinylidene fluoride) membranes were activated with a 1M solution of LiClO4 in EC/PC and showed a high ionic conductivity about 1.6 mS cm−1 at room temperature. The electrochemical stability is at 5.0 V versus Li+/Li, making them suitable for practical applications in lithium cells. Cycling tests of Li/GPE/LiFePO4 cells showed the suitability of the electrospun membranes made of TPU/PVdF (80/20, w/w) for applications in lithium rechargeable batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Dispositional resistance to change and hospital physicians' use of electronic medical records: A multidimensional perspective
Authors: Nov Oded , Schecter William
Published: February 2012

Although electronic medical records (EMR) adoption by health care organizations has been widely studied, little is known about the determinants of EMR individual use by physicians after institutional adoption has taken place. In this study, the determinants of inpatient physicians' continuous use of EMR were studied. Four dimensions of EMR use were analyzed: use intensity, use extent, use frequency, and use scope. A web‐based survey was administered to physicians at a large university hospital; respondents filled out a survey with questions relating to their EMR use, attitude, beliefs, work style, and dispositional resistance to change. Structural equation modeling was carried out to analyze the relationship between these factors. Physicians were found to differ substantially in the scope, extent, and intensity of their EMR use. Their attitude toward EMR use was associated with all use dimensions. Dispositional resistance to change was negatively related to perceived ease of use and with perceived usefulness both directly and through the mediation of compatibility with preferred work style. Time loss was negatively related to both perceived usefulness and attitude toward EMR use. Implications for research and practice are discussed.
CharaParser for fine‐grained semantic annotation of organism morphological descriptions
Authors: Cui Hong
Published: February 2012

Biodiversity information organization is looking beyond the traditional document‐level metadata approach and has started to look into factual content in textual documents to support more intelligent and semantic‐based access. This article reports the development and evaluation of CharaParser, a software application for semantic annotation of morphological descriptions. CharaParser annotates semistructured morphological descriptions in such a detailed manner that all stated morphological characters of an organ are marked up in Extensible Markup Language format. Using an unsupervised machine learning algorithm and a general purpose syntactic parser as its key annotation tools, CharaParser requires minimal additional knowledge engineering work and seems to perform well across different description collections and/or taxon groups. The system has been formally evaluated on over 1,000 sentences randomly selected from Volume 19 of Flora of North American and Part H of Treatise on Invertebrate Paleontology. CharaParser reaches and exceeds 90% in sentence‐wise recall and precision, exceeding other similar systems reported in the literature. It also significantly outperforms a heuristic rule‐based system we developed earlier. Early evidence that enriching the lexicon of a syntactic parser with domain terms alone may be sufficient to adapt the parser for the biodiversity domain is also observed and may have significant implications.
Inherent Electrochemistry and Activation of Chemically Modified Graphenes for Electrochemical Applications
Authors: Moo James Guo Sheng , Ambrosi Adriano , Bonanni Alessandra , Pumera Martin
Published: February 2012

Graphene research is currently at the frontier of electrochemistry. Many different graphene‐based materials are employed by electrochemists as electrodes in sensing and in energy‐storage devices. Because the methods for their preparation are inherently different, graphene materials are expected to exhibit different electrochemical behaviors depending on the functionalities and density of defects present. Electrochemical treatment of these “chemically modified graphenes” (CMGs) represents an easy approach to alter surface functionalities and consequently tune the electrochemical performance. Herein, we report a preliminary electrochemical characterization of four common chemically modified graphenes, namely: graphene oxide, graphite oxide, chemically reduced graphene oxide, and thermally reduced graphene oxide. These CMGs were compared with graphite as a reference material. Cyclic voltammetry was used to ascertain the chemical functionalities present and to understand the potential ranges in which the materials were electroactive. Electrochemical treatment with either an oxidative or a reductive fixed potential were then carried out to activate these chemically modified graphenes. The effects of such electrochemical treatments on their electrocatalytic properties were then investigated by cyclic voltammetry in the presence of well‐known redox probes, such as [Fe(CN)6]4−/3−, Fe3+/2+, [Ru(NH3)6]2+/3+, and ascorbic acid. Thermally reduced graphene oxide exhibited the best electrochemical behavior amongst all of the CMGs, with the fastest rate of heterogeneous electron transfer (HET) and the lowest overpotentials. These findings will have far‐reaching consequences for the evaluation of different CMGs as electrode materials in electrochemical devices.
Morphological Changes of Pure Micro‐ and Nano‐Sized CaCO3 during a Calcium Looping Cycle for CO2 Capture
Authors: Luo C. , Shen Q. , Ding N. , Feng Z. , Zheng Y. , Zheng C.
Published: February 2012

Cyclic CO2 capture using CaO‐based sorbents derived from commercial pure micro‐sized CaCO3 and nano‐sized CaCO3 was investigated, focusing on the different characteristics of carbonation conversions, carbonation rates, surface areas, pore volumes, morphological changes, and microstrains of two sorbents during high‐temperature reactions. The results indicated that the CaO‐based sorbent derived from nano‐sized CaCO3 (NC‐CaO) provided higher carbonation conversions and carbonation rates than the CaO‐based sorbent derived from micro‐sized CaCO3 (MC‐CaO) in the cyclic CO2 capture reactions. Furthermore, NC‐CaO retained its fast carbonation rate at the beginning of each cycle for several tens of seconds. In contrast, the carbonation rate of MC‐CaO diminished with an increase in the cycle number. Unfortunately, NC‐CaO sintered more easily. Its grains, which were composed of numerous spherical nanocrystallites, suffered from dramatic morphological changes during high‐temperature reactions. A mechanism of grain boundary migration was employed to explain the sintering of CaO‐based sorbent. The smaller crystallites were more susceptible to be merged by the bigger crystallites during high‐temperature reactions.
Multiple Keys for a Single Lock: The Unusual Structural Plasticity of the Nucleotidyltransferase (4′)/Kanamycin Complex
Authors: Matesanz Ruth , Diaz José Fernando , Corzana Francisco , Santana Andrés G. , Bastida Agatha , Asensio Juan Luis
Published: February 2012

The most common mode of bacterial resistance to aminoglycoside antibiotics is the enzyme‐catalysed chemical modification of the drug. Over the last two decades, significant efforts in medicinal chemistry have been focused on the design of non‐ inactivable antibiotics. Unfortunately, this strategy has met with limited success on account of the remarkably wide substrate specificity of aminoglycoside‐modifying enzymes. To understand the mechanisms behind substrate promiscuity, we have performed a comprehensive experimental and theoretical analysis of the molecular‐recognition processes that lead to antibiotic inactivation by Staphylococcus aureus nucleotidyltransferase 4′(ANT(4′)), a clinically relevant protein. According to our results, the ability of this enzyme to inactivate structurally diverse polycationic molecules relies on three specific features of the catalytic region. First, the dominant role of electrostatics in aminoglycoside recognition, in combination with the significant extension of the enzyme anionic regions, confers to the protein/antibiotic complex a highly dynamic character. The motion deduced for the bound antibiotic seem to be essential for the enzyme action and probably provide a mechanism to explore alternative drug inactivation modes. Second, the nucleotide recognition is exclusively mediated by the inorganic fragment. In fact, even inorganic triphosphate can be employed as a substrate. Third, ANT(4′) seems to be equipped with a duplicated basic catalyst that is able to promote drug inactivation through different reactive geometries. This particular combination of features explains the enzyme versatility and renders the design of non‐inactivable derivatives a challenging task.
A Disulfide Bridge Allows for Site‐Selective Binding in Liver Bile Acid Binding Protein Thereby Stabilising the Orientation of Key Amino Acid Side Chains
Authors: Tomaselli Simona , Assfalg Michael , Pagano Katiuscia , Cogliati Clelia , Zanzoni Serena , Molinari Henriette , Ragona Laura
Published: February 2012

The presence of a disulfide bridge in liver bile acid binding protein (L‐BABP/S‐S) allows for site‐selective binding of two bile acids, glycochenodeoxycholic (GCDA) and glycocholic acid (GCA), differing only in the presence of a hydroxyl group. The protein form devoid of the disulfide bridge (L‐BABP) binds both bile salts without discriminating ability. We investigate the determinants of the molecular recognition process in the formation of the heterotypic L‐BABP/S‐S complex with GCA and GCDA located in the superficial and inner protein sites, respectively. The comparison of the NMR spectroscopy structure of heterotypic holo L‐BABP/S‐S, the first reported for this protein family, with that of the homotypic L‐BABP complex demonstrates that the introduction of a S–S link between adjacent strands changes the conformation of three key residues, which function as hot‐spot mediators of molecular discrimination. The favoured χ1 rotameric states (t, g+ and g− for E99, Q100 and E109 residues, respectively) allow the onset of an extended intramolecular hydrogen‐bond network and the consequent stabilisation of the side‐chain orientation of a buried histidine, which is capable of anchoring a specific ligand.
CH/π‐Interaction‐Guided Self‐Assembly in π‐Conjugated Oligomers
Authors: Goel Mahima , Jayakannan Manickam
Published: February 2012

We report CH/π hydrogen‐bond‐driven self‐assembly in π‐conjugated skeletons based on oligophenylenevinylenes (OPVs) and trace the origin of interactions at the molecular level by using single‐crystal structures. OPVs were designed with appropriate pendants in the aromatic core and varied by hydrocarbon or fluorocarbon tails along the molecular axis. The roles of aromatic π‐stack, van der Waals forces, fluorophobic effect and CH/π interactions were investigated on the theromotropic liquid crystallinity of OPV molecules. Single‐crystal structures of hydrocarbon OPVs provided direct evidence for the existence of CH/π interactions between the π‐ring (H‐bond acceptor) and alkyl CH (H‐bond donor). The four important crystallographic parameters, dc−x=3.79 Å, θ=21.49°, φ=150.25° and dHp−x=0.73 Å, matched in accordance with typical CH/π interactions. The CH/π interactions facilitate the close‐packing of mesogens in x–y planes, which were further protruded along the c axis producing a lamellar structure. In the absence of CH/π interactions, van der Waals interactions drove the assembly towards a Schlieren nematic texture. Fluorocarbon OPVs exhibited smectic liquid‐crystalline textures that further underwent Smectic A (SmA) to Smectic C (SmC) phase transitions with shrinkage up to 11 %. The orientation and translational ordering of mesogens in the liquid‐crystalline (LC) phases induced H‐ and J‐type molecular arrangements in fluorocarbon and hydrocarbon OPVs, respectively. Upon photoexcitation, the H‐ and J‐type molecular arrangements were found to emit a blue or yellowish/green colour. Time‐resolved fluorescence decay measurements confirmed longer lifetimes for H‐type smectic OPVs relative to that of loosely packed one‐dimensional nematic hydrocarbon‐tailed OPVs.
Direct Regiospecific and Highly Enantioselective Intermolecular α‐Allylic Alkylation of Aldehydes by a Combination of Transition‐Metal and Chiral Amine Catalysts
Authors: Afewerki Samson , Ibrahem Ismail , Rydfjord Jonas , Breistein Palle , Córdova Armando
Published: February 2012

The first direct intermolecular regiospecific and highly enantioselective α‐allylic alkylation of linear aldehydes by a combination of achiral bench‐stable Pd0 complexes and simple chiral amines as co‐catalysts is disclosed. The co‐catalytic asymmetric chemoselective and regiospecific α‐allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2‐alkyl alcohols with high enantiomeric ratios (up to 98:2 e.r.; e.r.=enantiomeric ratio). It is also an expeditious entry to valuable 2‐alkyl substituted hemiacetals, 2‐alkyl‐butane‐1,4‐diols, and amines. The concise co‐catalytic asymmetric total syntheses of biologically active natural products (e.g., Arundic acid) are disclosed.
De novo acute myeloid leukemia risk factors
Authors: Strom Sara S. , Oum Robert , Elhor Gbito Kplola Y. , Garcia‐Manero Guillermo , Yamamura Yuko
Published: February 2012

BACKGROUND:

Acute myeloid leukemia (AML) is comprised of several bone marrow‐based cancers and is the most common type of leukemia in the United States. The etiology of AML is not well understood. A case‐control study was conducted at The University of Texas M. D. Anderson Cancer Center to investigate associations between lifestyle characteristics and the risk of AML in Texas.

METHODS:

This study included 638 adult patients with de novo AML (cases) and a group of 636 matched controls. Interviewer‐administered questionnaires were used to collect demographic and occupational data. The distribution of cases by World Health Organization (WHO) subtype was 71 patients (11%) with recurrent cytogenetic abnormalities (AML‐RCA), 134 patients (21%) with multilineage dysplasia (AML‐MD), and 389 patients (61%) with AML not otherwise categorized (AML‐NOC). Multivariate logistic regression analyses were performed among all AML cases and among both sexes and each WHO subgroup.

RESULTS:

Among men, heavy smoking (≥30 pack‐years; odds ratio [OR], 1.86) and occupational solvent exposure at low levels (OR, 2.87) or moderate/high levels (OR, 4.13) statistically significantly increased the risk of AML. Among women, obesity (OR, 1.62) and solvent exposure to low levels (OR, 2.73) or moderate/high levels (OR, 3.90) increased the risk of AML. Across WHO subtypes, obesity was associated with a statistically significantly increased risk of AML‐RCA (OR, 3.15), whereas solvent exposure increased the risk in all subtypes at low levels (AML‐RCA: OR, 4.11; AML‐MD: OR, 2.54) and moderate/high levels (AML‐RCA: OR, 5.13; AML‐MD: OR, 3.02). A joint effect between smoking and solvent exposure was observed, and the highest risk was observed among smokers who had solvent exposure (OR, 4.51).

CONCLUSIONS:

The current results suggested that several factors play a role in AML predisposition with possible joint effects. Risk profiles for AML differed by sex and WHO subtype. Cancer 2012. © 2012 American Cancer Society.
Hormone receptor and human epidermal growth factor receptor 2 status evaluation on ThinPrep specimens from breast carcinoma
Authors: Pegolo Enrico , Machin Piernicola , Riosa Franca , Bassini Anna , Deroma Laura , Di Loreto Carla
Published: February 2012

BACKGROUND:

Fine‐needle aspiration cytology (FNAC) is a well‐accepted procedure for the diagnosis and biological characterization of breast carcinoma. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status have a strong prognostic and predictive value in invasive breast carcinoma (IBC). ThinPrep (TP) cytology, which uses an alcohol‐based fixative, is increasingly being used for immunocytochemistry. In this study, the authors compared the immunocytochemical evaluation of hormone receptors (HR) and HER2 on TP‐processed FNAC with the immunohistochemical analysis performed on the corresponding formalin‐fixed paraffin‐embedded (FFPE) breast tumor specimens, which are considered the gold standard.

METHODS:

FNACs were performed on 116 primary IBCs at the time of diagnosis and subjected to immunocytochemical evaluation of HR and HER2 using the TP method. The same markers were immunohistochemical evaluated on the corresponding FFPE tissue specimens. HER2 fluorescent in situ hybridization analysis was performed only on the equivocal immunohistochemical results.

RESULTS:

The HR results of the TP cytology specimens showed a very good agreement with those of the corresponding FFPE tissue samples (Cohen kappa test = 0.92; concordance rate = 98%) for estrogen receptor, and a good agreement (kappa = 0.76; concordance rate = 90.9%) for progesterone receptor. A perfect agreement (kappa = 1) was observed between TP and FFPE tissue samples in evaluating HER2 status.

CONCLUSIONS:

Alcohol‐based fixation seems not to affect the immunocytochemical evaluation of HR and HER2. Considering the high levels of agreement between the evaluation of HR and HER2, on both cytology specimens and on the corresponding FFPE tissue samples, the authors concluded that the TP technique can be routinely used for the biological characterization of IBC. Cancer (Cancer Cytopathol) 2012;. © 2012 American Cancer Society.
Endobronchial ultrasound‐guided transbronchial needle aspiration diagnosis of mediastinal lymph node metastasis of mucinous adenocarcinoma: Arborizing stromal meshwork fragments as a diagnostic clue
Authors: Samad Arbaz , Peltola Justin C. , Mitiek Mohi O. , Jessurun Jose , Manivel J. Carlos , Pambuccian Stefan E.
Published: February 2012

Endobronchial Ultrasound‐Guided Transbronchial Needle Aspiration (EBUS‐TBNA) is a reliable and accurate method for the diagnosis of mediastinal metastases in patients with pulmonary and extrathoracic neoplasms. We report the cytopathologic findings of a case of metastatic signet‐ring cell carcinoma with abundant extracellular mucin production in the mediastinal lymph nodes of a 41‐year‐old woman, who presented with nausea, abdominal pain, and weight loss. Imaging studies showed a renal mass, numerous lung nodules, and mediastinal and retroperitoneal lymphadenopathy. EBUS‐TBNA of level 4R and 7 lymph nodes showed abundant, thick, “clean” mucus with entrapped ciliated bronchial cells, rare histiocytes, and fragments of cartilage. No neoplastic cells could be identified in Diff‐Quik®‐stained smears during the rapid on‐site evaluation, but rare signet‐ring cells were identified in the Papanicolaou‐stained smears and cellblock sections. A distinctive feature of the aspirates was the presence of large branching (arborizing), “spidery” stromal fiber meshwork fragments. These stained metachromatically (magenta) with Romanowsky‐type stains and cyanophilic to orangeophilic with Papanicolaou stains and showed occasional attached bland spindle cells, but had no capillary lumina or CD31‐staining endothelial cells. The tumor cells were strongly and diffusely positive for CEA, CDX2, CK7, CK20, and MUC2, supporting the diagnosis of a metastatic signet‐ring cell adenocarcinoma, most likely of gastrointestinal origin. We believe that the presence of the large spidery stromal fiber fragments is a useful clue to the presence of a mucinous neoplasm in EBUS‐TBNA and allows the differentiation of the neoplastic mucus from contaminating endobronchial mucus. Diagn. Cytopathol. 2013;41:896–900. © 2012 Wiley Periodicals, Inc.
Evolution of reproductive morphology among recently diverged taxa in the Drosophila mojavensis species cluster
Authors: Richmond Maxi Polihronakis , Johnson Sarah , Markow Therese A.
Published: February 2012

The morphological evolution of sexual traits informs studies of speciation due to the potential role of these characters in reproductive isolation. In the current study, we quantified and compared genitalic variation within the Drosophila mojavensis species cluster to infer the mode of evolution of the male aedeagus. This system is ideal for such studies due to the opportunity to test and compare levels of variation along a divergence continuum at various taxonomic levels within the group. Shape variation was quantified using elliptic Fourier descriptors and compared among the four D. mojavensis host races, and between D. mojavensis and its sister species Drosophila arizonae. Aedeagus shape was diagnostic for D. arizonae, and among three of the four D. mojavensis subspecies. In each of these cases, there was less variation within subspecies than among subspecies, which is consistent with the pattern predicted if genitalia are evolving according to a punctuated change model, and are involved with mate recognition. However, aedeagus shape in Drosophila mojavensis sonorensis was highly variable and broadly overlapping with the other three subspecies, suggesting aedeagus evolution in this subspecies is more complex and subject to additional evolutionary factors. These results are interpreted and discussed in the context of selection on mate recognition systems and the potential for failed copulation.
Electroosmotic flow modulation in capillary electrophoresis by organic cations from ionic liquids
Authors: Mendes Acácio , Branco Luís C. , Morais Cristiana , Simplício Ana Luísa
Published: February 2012

This paper describes the ability of several ionic liquids cations for electroosmotic flow modulation in capillary electrophoresis. Organic salts based on phosphonium, sulfonium, cysteinium, ammonium, and guanidinium cations were selected to study this property. In addition, the synergistic effect of these compounds in cyclodextrin chiral separation was also evaluated. In comparison with most studied imidazolium‐based ionic liquids, several of the cations studied, are stronger modifiers in terms of electroosmotic flow (EOF) modulation. Phosphonium‐based compounds and tri‐octyl methylammonium chloride ([Aliquat]Cl) had the strongest ability to reverse EOF both in acidic and in basic conditions and had the lowest EOF reversal concentrations in the presence of hydroxypropyl‐β‐cyclodextrin. EOF modulation ability of phosphonium cations also contributed to the improvement of chiral separation of DL‐propranolol by hydroxypropyl‐β‐cyclodextrin at lower concentrations in comparison with most commonly used EOF modulators such as tetrabutylammonium phosphate.
Semantic memory and language dysfunction in early Alzheimer's disease: a review
Authors: Verma M. , Howard R. J.
Published: February 2012

Background

Language impairment in Alzheimer's disease occurs early, and language function deteriorates with progression of the illness to cause significant disability. This review focuses on language dysfunction in Alzheimer's disease and the contribution of semantic memory impairment.

Methods

Electronic publication databases were searched for literature relevant to the review. Additionally, individual references were examined to elicit further studies not found by online search.

Results

Language impairment in Alzheimer's disease initially affects verbal fluency and naming before breakdown in other facets. Naming and fluency require integrity of semantic concepts, and dysfunction may be a marker of primary semantic memory impairment rather than overall cognitive decline. Research suggests the presence of semantic loss several years prior to diagnosis. Imaging studies indicate an altered connectivity state with respect to language networks, and this is associated with potential semantic failure. This state may also be present in individuals with established risk factors for Alzheimer's disease. Compensatory recruitment of alternative cortical areas to supplement language function appears to occur and may be a target for future intervention.

Conclusions

Identifying and classifying the nature and degree of language impairment more closely could aid in developing targeted therapies. Treatments already established in other aphasic states, such as post‐stroke, may be especially relevant. The nature of these and the protective nature of cognitive reserve are potential therapeutic avenues. Copyright © 2012 John Wiley & Sons, Ltd.
Deep sequencing reveals predominant expression of miR‐21 amongst the small non‐coding RNAs in retinal microvascular endothelial cells
Authors: Guduric‐Fuchs Jasenka , O'Connor Anna , Cullen Angela , Harwood Laura , Medina Reinhold J. , O'Neill Christina L. , Stitt Alan W. , Curtis Tim M. , Simpson David A.
Published: February 2012

The retinal vascular endothelium is essential for angiogenesis and is involved in maintaining barrier selectivity and vascular tone. The aim of this study was to identify and quantify microRNAs and other small regulatory non‐coding RNAs (ncRNAs) which may regulate these crucial functions. Primary bovine retinal microvascular endothelial cells (RMECs) provide a well‐characterized in vitro system for studying angiogenesis. RNA extracted from RMECs was used to prepare a small RNA library for deep sequencing (Illumina Genome Analyzer). A total of 6.8 million reads were mapped to 250 known microRNAs in miRBase (release 16). In many cases, the most frequent isomiR differed from the sequence reported in miRBase. In addition, five novel microRNAs, 13 novel bovine orthologs of known human microRNAs and multiple new members of the miR‐2284/2285 family were detected. Several ∼30 nucleotide sno‐miRNAs were identified, with the most highly expressed being derived from snoRNA U78. Highly expressed microRNAs previously associated with endothelial cells included miR‐126 and miR‐378, but the most highly expressed was miR‐21, comprising more than one‐third of all mapped reads. Inhibition of miR‐21 with an LNA inhibitor significantly reduced proliferation, migration, and tube‐forming capacity of RMECs. The independence from prior sequence knowledge provided by deep sequencing facilitates analysis of novel microRNAs and other small RNAs. This approach also enables quantitative evaluation of microRNA expression, which has highlighted the predominance of a small number of microRNAs in RMECs. Knockdown of miR‐21 suggests a role for this microRNA in regulation of angiogenesis in the retinal microvasculature. J. Cell. Biochem. 113: 2098–2111, 2012. © 2012 Wiley Periodicals, Inc.
Structural and electronic property responses to the arsenic/phosphorus exchange in GC‐related DNA of the B‐form
Authors: Gu Jiande , Wang Jing , Xie Yaoming , Leszczynski Jerzy , Schaefer Henry F.
Published: February 2012

The suggestion that phosphorus/arsenic replacement in DNA can play a role in living things has generated great controversy (Wolfe‐Simon et al., Science 2011, 332, 1163). Examined here theoretically are substitution effects on Watson–Crick base pairing and base stacking patterns in realistic DNA subunits. Using duplex DNA models deoxyguanylyl‐3′,5′‐deoxycytidine ([dGpdC]2) and deoxycytidyly‐3′,5′‐deoxyguanosine ([dCpdG)]2), this research reveals that the geometric variations caused by the As/P exchange are small and are limited to the phosphate/arsenate groups. As/P replacement leads to alterations of ∼0.15 Å in P/AsO bond lengths and less than 1.5° variations in OP/AsO angles. The Watson–Crick base pairing and base stacking patterns are independent of the As/P replacement. The vertical electron detachment energies are also largely unaffected. However, the electron capture ability of the DNA units is improved by the As substitution. The arsenate is found to be the main electron acceptor in As‐DNA. The results are relevant to the possible existence of viable As‐DNAs, at least in the guanine and cytosine (GC)‐related B‐form DNA. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012
Influence of the solvent representation on vibrational entropy calculations: Generalized born versus distance‐dependent dielectric model
Authors: Kopitz Hannes , Cashman Daniel A. , Pfeiffer‐Marek Stefania , Gohlke Holger
Published: February 2012

The harmonic model is the most popular approximation for estimating the “configurational” entropy of a solute in molecular mechanics/Poisson‐Boltzmann solvent accessible surface area (MM/PBSA)‐type binding free energy calculations. Here, we investigate the influence of the solvent representation in the harmonic model by comparing estimates of changes in the vibrational entropies for 30 trypsin/ligand complexes on ligand binding. Second derivatives of Amber generalized Born (GB) solvation models are available in the nucleic acid builder code. They allow one to use these models for the calculation of vibrational entropies instead of using a simpler solvation model based on a distance‐dependent dielectric (DDD) constant. Estimates of changes in the vibrational entropies obtained with a DDD model are systematically and significantly larger, by on average, 6 kcal mol−1 (at T = 300 K), than estimates obtained with a GB model and so are more favorable for complex formation. The difference becomes larger the more the vibrational entropy contribution disfavors complex formation, that is, the larger the ligand is (for the complexes considered here). A structural decomposition of the estimates into per‐residue contributions reveals polar interactions between the ligand and the surrounding protein, in particular involving charged nitrogens, as a main source of the differences. Snapshots minimized with the DDD model showed a structural deviation from snapshots minimized in explicit water that is larger by, on average, 0.5 Å RMSD compared to snapshots that were minimized with GBHCT. As experimental vibrational entropies of biomacromolecules are elusive, there is no direct way to establish a solvent model's superiority. Thus, we can only recommend using the GB harmonic model for vibrational entropy calculations based on the reasoning that smaller structural deviations should point to the implicit solvent model that closer approximates the energy landscape of the solute in explicit solvent. © 2012 Wiley Periodicals, Inc.
Optimization of oxygen transfer through venturi‐based systems applied to the biological sweetening of biogas
Authors: Rodriguez Ginesta , Dorado Antonio David , Bonsfills Anna , Sanahuja Ricard , Gabriel David , Gamisans Xavier
Published: February 2012

BACKGROUND: Dissolved oxygen is a key parameter in the biological removal of gaseous H2S since sulfide‐oxidizing bacteria convert H2S into elemental sulfur instead of sulfate under limiting dissolved oxygen concentrations. Elemental sulfur is insoluble in water and accumulates in the packing material in biotrickling filters, increasing the pressure drop and operating costs. A set of mass transfer tests was performed in a versatile pilot plant to supply the necessary oxygen for the biological oxidation of H2S. The plant can be operated with three different commercial gas–liquid contactor devices: a venturi ejector, a jet‐venturi and a diffuser. The effects of different geometric and operating parameters have been tested for each device (including pressure rise and sulfate content to mimic real wastewater treatment plant conditions).

RESULTS: Results showed that the bioreactor pressure has a strong influence on the mass transfer characteristics of the three oxygenation devices. In addition, the ionic strength of the solution has a low influence on the mass transfer process.

The SOTE values obtained for the diffuser, jet‐venturi and venturi ejector were 8.7%, 7.2% and 6.0%, respectively (pure water experiments), while SAE values were in the range 6.3–5.5 × 10−2, 4.1–4.8 × 10−1 and 3.1–3.7 × 10−1 kg O2 kW−1 h−1, respectively.

CONCLUSIONS: The jet‐venturi offers the best oxygen transfer with lower power consumption compared with the diffuser and venturi ejector. The practical implementation of the most efficient aeration technology is possible from both technical and economical perspectives. Copyright © 2012 Society of Chemical Industry
Influences of the insertion method in glass ionomer cement porosity
Authors: Da Mata Margareth , Santos‐Pinto Lourdes , Cilense Zuanon Angela Cristina
Published: February 2012

The aim of this study was to evaluate the presence of porosities inside the glass ionomer cement (GIC) after different techniques of material insertion. MATERIAL AND METHOD: Specimens were prepared with high‐viscosity GIC Ketac Molar Easymix and divided into three groups according to the insertion method: spatula (PI), Centrix injector (CI), and low‐cost syringe (LCS). The specimens were fractured and observed with scanning electronic microscopy to quantitatively evaluate porosity inside the material using Image J Software. RESULTS: Statistical analysis, ANOVA application, and Tukey test to significance level of 5%, revealed that there was no statistical difference between the groups. CONCLUSION: Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs. Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.
Effect of disinfectant solutions on gutta‐percha and resilon cones
Authors: Prado Maíra , Gusman Heloisa , Gomes Brenda P.F.A. , Simão Renata A.
Published: February 2012

The aim of this study was to evaluate the effects of the 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and MTAD solutions on the surface of gutta‐percha and Resilon cones by using atomic force microscopy (AFM). Accessory cones were washed and dried. The cones were randomly divided into six groups: gutta‐percha immersed in NaOCl, CHX, and MTAD, and Resilon immersed in NaOCl, CHX, and MTAD. AFM images of the same area were made in different periods of time. JPK™ Image Processing Software was used to evaluate the images. The parameters used to evaluate the changes were RMS and line profiles. No statistically significant change was observed in the RMS values. The line profiles detected changes only for gutta‐percha surfaces after immersion in NaOCl and MTAD solutions. In conclusion, 5.25% NaOCl and MTAD are associated with local changes in surface roughness of gutta‐percha cones. No change was observed when 2% CHX was used. The use of all tested solutions did not produce any changes on Resilon surface. Microsc. Res. Tech. 75:791–795, 2012. © 2012 Wiley Periodicals, Inc.
MAX WEBER IN THE AMERICAN JOURNAL OF SOCIOLOGY: A CASE OF CIRCULATING KNOWLEDGE
Authors: RIJKS MARLISE
Published: February 2012

By the middle of the 1970s, a Max Weber revival commenced in American sociology. Almost 75 percent of the articles on Weber in the American Journal of Sociology published in the past six decades appeared in the 1970s and 1980s. The Weber revival in American sociology is a phenomenon observed in leading literature. New translations and publications are frequently indicated reasons for the renewed interest in Weber. Without dismissing this factor, it is not an entirely satisfactory explanation. This article accounts for the Weber revival in a new way. Taking the American Journal of Sociology as a case study, I argue that the Weber revival was a case of circulating knowledge. Certain historically set issues led to a reorientation of Weber, which meant that knowledge about Weber was moved, extended, and transformed.
Control‐matched computational evaluation of tendo‐femoral contact in patients with posterior‐stabilized total knee arthroplasty
Authors: Hoops Heather E. , Johnson Derek R. , Kim Raymond H. , Dennis Douglas A. , Baldwin Mark A. , Fitzpatrick Clare K. , Laz Peter J. , Rullkoetter Paul J.
Published: February 2012

Painful patellar crepitus is a potential complication in up to 14% of patients following posterior‐stabilized (PS) total knee arthroplasty (TKA). A recent clinical study identified influential patient and surgical variables by comparing a group of crepitus patients with controls matched for age, sex, and body mass index. The purpose of our study was to evaluate effects of variables identified as significant in the clinical study, including patellar ligament length, femoral component flexion, patellar button size, and position of the joint line, on contact between the quadriceps tendon and the PS femoral component. A previously verified finite element model was utilized to estimate tendo‐femoral contact during deep flexion activity. Using discrete perturbations, the computational model confirmed the clinical findings in that an increased patellar ligament length, flexed femoral component, lowered joint line, and larger patellar component all reduced potentially deleterious contact near the intercondylar notch. With the selected level of anatomic and component alignment perturbations, the most influential factor affecting tendo‐femoral contact was patellar ligament length. Three crepitus patients with matched controls were subsequently modeled, and contact with the anterior border of the notch was present in each crepitus patient, but none of the controls. Alternative surgical alignments for these patients were evaluated to improve the potential long‐term outcomes. By characterizing conditions that may lead to painful crepitus, the modeling approach supports clinicians by identifying pre‐surgical indicators and important alignment parameters to control intraoperatively. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1355–1361, 2012