bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Stable Aminoacyl‐tRNA Analogs
Authors: Chemama Maryline , Fonvielle Matthieu , Lecerf Maxime , Mellal Dénia , Fief Hélène , Arthur Michel , Etheve‐Quelquejeu Mélanie
Published: March 2011

Aminoacyl‐tRNAs have important roles in a variety of biological processes. Here, we describe the synthesis of stable aminoacyl‐tRNA analogs containing 1,4‐substituted 1,2,3‐triazole rings. The procedure involves (i) copper‐catalyzed cycloadditions of 3′‐or 2′‐azido‐adenosine and alkynes, (ii) coupling between the resulting triazole‐deoxyadenosine derivatives and a deoxycytidine phosphoramidite, and (iii) the enzymatic ligation of the 2′‐ or 3′‐triazole‐dinucleotides with a 22‐nt RNA microhelix that mimics the acceptor arm of tRNA. Each nucleoside and nucleotide intermediate was characterized by MS spectrometry and 1H, 31P, and 13C NMR spectroscopy, and the tRNA‐analogs were assayed for inhibition of FemXWv, an alanyl‐transferase essential for the formation of the peptidoglycan network of Gram‐positive bacterial pathogens. The low IC50 values obtained (2 to 4 µM) indicate that the five‐membered triazole rings acted as an isosteres of esters and can be used for the design of stable aminoacyl‐tRNA analogs. Curr. Protoc. Nucleic Acid Chem. 44:4.44.1‐4.44.33. © 2011 by John Wiley & Sons, Inc.
Self‐Assembled Nanometer‐Scale Magnetic Networks on Surfaces: Fundamental Interactions and Functional Properties
Authors: Carbone Carlo , Gardonio Sandra , Moras Paolo , Lounis Samir , Heide Marcus , Bihlmayer Gustav , Atodiresei Nicolae , Dederichs Peter Heinz , Blügel Stefan , Vlaic Sergio , Lehnert Anne , Ouazi Safia , Rusponi Stefano , Brune Harald , Honolka Jan , Enders Axel , Kern Klaus , Stepanow Sebastian , Krull Cornelius , Balashov Timofey , Mugarza Aitor , Gambardella Pietro
Published: March 2011

Nanomagnets of controlled size, organized into regular patterns open new perspectives in the fields of nanoelectronics, spintronics, and quantum computation. Self‐assembling processes on various types of substrates allow designing fine‐structured architectures and tuning of their magnetic properties. Here, starting from a description of fundamental magnetic interactions at the nanoscale, we review recent experimental approaches to fabricate zero‐, one‐, and two‐dimensional magnetic particle arrays with dimensions reduced to the atomic limit and unprecedented areal density. We describe systems composed of individual magnetic atoms, metal‐organic networks, metal wires, and bimetallic particles, as well as strategies to control their magnetic moment, anisotropy, and temperature‐dependent magnetic behavior. The investigation of self‐assembled subnanometer magnetic particles leads to significant progress in the design of fundamental and functional aspects, mutual interactions among the magnetic units, and their coupling with the environment.
Surface‐Confined Self‐Assembly of Di‐carbonitrile Polyphenyls
Authors: Klyatskaya Svetlana , Klappenberger Florian , Schlickum Uta , Kühne Dirk , Marschall Matthias , Reichert Joachim , Decker Régis , Krenner Wolfgang , Zoppellaro Giorgio , Brune Harald , Barth Johannes V. , Ruben Mario
Published: March 2011

This Feature Article reports on the controlled formation and structure‐functionality aspects of vacuum‐deposited self‐assembled organic and metal‐organic networks at metal surfaces using ditopic linear and nonlinear molecular bricks, namely di‐carbonitrile polyphenyls. Surface confined supramolecular organization of linear aromatic molecules leads to a fascinating variety of open networks. Moreover, cobalt‐directed assembly of the same linear linkers reveals highly regular, open honeycomb networks with tunable pore sizes representing versatile templates for the organization of molecular guests or metal clusters and the control of supramolecular dynamers. In addition, the 2D nanopore organic networks act as arrays of quantum corrals exhibiting confinement of the surface‐electronic states of the metallic substrate. A reduction of the linker symmetry leads to the formation of disordered, glassy coordination networks, which represent a structural model for amorphous materials.
All‐Carbon Nanotube‐Based Flexible Field‐Emission Devices: From Cathode to Anode
Authors: Jeong Hee Jin , Jeong Hae Deuk , Kim Ho Young , Kim Jun Suk , Jeong Seung Yol , Han Joong Tark , Bang Dae Suk , Lee Geon‐Woong
Published: March 2011

The fabrication of a flexible field‐emission device (FED) using single‐walled carbon nanotube (SWNT) network films as the conducting electrodes (anode and cathode) and thin multi‐walled CNT/TEOS hybrid films as the emitters is reported. P‐type doping with gold ions and passivation with tetraethylorthosilicate (TEOS) made the SWNT network film highly conductive and environmentally stable, and hence a good alternative to conventional indium tin oxide electrodes. CNT/TEOS hybrid emitters showed high current density, low turn‐on field, and long‐term emission stability, compared with CNT emitters; these characteristics can be attributed to the TEOS sol, acting both as a protective layer surrounding the nanotube tip, and as an adhesive layer enhancing the nanotube adhesion to the substrate. All‐CNT‐based flexible FEDs fabricated by this approach showed high flexibility in field emission characteristics and extremely bright electron emission patterns.
Molecular Stacking Induced by Intermolecular C–H···N Hydrogen Bonds Leading to High Carrier Mobility in Vacuum‐Deposited Organic Films
Authors: Yokoyama Daisuke , Sasabe Hisahiro , Furukawa Yukio , Adachi Chihaya , Kido Junji
Published: March 2011

Simple bottom‐up fabrication processes for molecular self‐assembly have been developed for the construction of higher‐order structures using organic materials, and have contributed to maximization of the potential of organic materials in chemical and bioengineering. However, their application to organic thin‐film devices such as organic light‐emitting diodes have not been widely considered because simple fabrication of a solid film containing an internal self‐assembly structure has been regarded as difficult. Here it is shown that the intermolecular C–H···N hydrogen bonds can be simply formed even in vacuum‐deposited organic films having flat interfaces. By designing the molecules containing pyridine rings properly for the intermolecular interaction, one can control the molecular stacking induced by the intermolecular hydrogen bonds. It is also demonstrated that the molecular stacking contributes to the high carrier mobility of the film. These findings provide new guidelines to improve the performance of organic optoelectronic devices and open up the possibilities for further development of organic devices with higher‐order structures.
Internally Referenced Remote Sensors for HF and Cl2 Using Reactive Porous Silicon Photonic Crystals
Authors: Ruminski Anne M. , Barillaro Giuseppe , Chaffin Charles , Sailor Michael J.
Published: March 2011

Remote detection of reactive analytes using optical films constructed from electrochemically prepared porous Si‐based photonic crystals is demonstrated. Porous Si samples are prepared to contain either surface oxide or surface Si‐H species, and analyte detection is based on irreversible reactions with HF(aq) or Cl2(g) analytes, respectively. HF dissolves silicon oxide from the porous matrix, causing an irreversible blue‐shift in the resonance peak of the photonic crystal. Cl2 reacts with the native Si‐H species present on the surface of as‐etched porous Si to generate reactive silicon halides that evaporate from the surface and/or react with air to convert to silicon oxide. Either Cl2‐related process reduces the net refractive index of the material that is detected as a blue shift in the spectrum. With sufficient analyte concentrations or exposure times, the spectral blue shifts are visible to the unaided eye. A portion of the porous nanostructure is filled with inert polystyrene, which acts as an internal spectral reference. The polymer fiducial protects that portion of the sensor from attack by the corrosive analytes. Reflectance spectra from both the polymer‐filled and the unfilled, reactive porous layers are acquired simultaneously. The fiducial marker also allows elimination of artifacts associated with shifts of the resonance peak upon changing the angle of incidence of the optical probe. Theoretical angle‐resolved spectra (transfer matrix method) show a good match with the experimental data. High‐temperature air or room‐temperature ozone oxidation reactions are used to prepare the HF‐reactive surface, and it is found that the ozone oxidation reaction produces a greater sensitivity to HF (LLOD of 0.1% HF in water).
A Versatile Method for the Reductive, One‐Pot Synthesis of Bare, Hydrophilic and Hydrophobic Magnetite Nanoparticles
Authors: Yathindranath Vinith , Rebbouh Leila , Moore David F. , Miller Donald W. , van Lierop Johan , Hegmann Torsten
Published: March 2011

A biocompatible, reliable, and particularly versatile synthesis of magnetic iron oxide nanoparticles (IONPs) is presented that uses iron(III) acetylacetonate Fe(acac)3 as an iron precursor and sodium borohydride as a reducing agent. Both the reaction temperature and the concentration of the reducing agent have considerable effects on the IONP size. These dependencies can be used to prepare IONPs ranging in size from 5 to 8 nm, as determined by transmission electron microscopy (TEM). Synthesis at room temperature or with higher sodium borohydride concentrations always resulted in smaller particle sizes. Powder X‐ray diffraction patterns show the presence of an iron oxide phase with a cubic unit cell and allow for the determination of the lattice parameters and average crystallite sizes for all synthesized IONPs. Transmission Mössbauer spectroscopy shows that the as‐synthesized IONPs are pure magnetite (Fe3O4) and is further used to elucidate the reaction pathway by analyzing iron intermediates formed prior to nanoparticle formation and precipitation. TEM and high‐resolution TEM reveal quasi‐spherical shapes and lattice fringes for most IONPs. With only minor modifications of the synthesis procedure, this versatile, one‐pot synthesis is proven to be suitable for the production of bare (uncoated) IONPs, IONPs with hydrophilic poly(ethylene glycol), L‐arginine, and L‐glutamic acid coatings, as well as IONPs with hydrophobic coatings such as oleic acid. All coated IONPs were characterized by FT‐IR spectroscopy. In addition, the bare IONPs could easily be modified post‐synthesis with a suitable capping agent using ultrasonication. To verify the biocompatibility of the IONPs, in vitro cytotoxicity studies were carried out on bare IONPs with intestinal (Caco2) and liver epithelial (HepG2) cell cultures using an 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay. Phase contrast microscopy after hematoxylin‐eosin staining showed the intact morphology of the Caco2 and HepG2 cells treated with IONPs.
Comparison of the Operation of Polymer/Fullerene, Polymer/Polymer, and Polymer/Nanocrystal Solar Cells: A Transient Photocurrent and Photovoltage Study
Authors: Li Zhe , Gao Feng , Greenham Neil C. , McNeill Christopher R.
Published: March 2011

We utilize transient techniques to directly compare the operation of polymer/fullerene, polymer/nanocrystal, and polymer/polymer bulk heterojunction solar cells. For all devices, poly(3‐hexylthiophene) (P3HT) is used as the electron donating polymer, in combination with either the fullerene derivative phenyl‐C61‐butyric acid methyl ester (PCBM) in polymer/fullerene cells, CdSe nanoparticles in polymer/nanocrystal cells, or the polyfluorene copolymer poly((9,9‐dioctylfluorene)‐2,7‐diyl‐alt‐[4,7‐bis(3‐hexylthien‐5‐yl)‐2,1,3‐benzothiadiazole]‐2,2‐diyl) (F8TBT) in polymer/polymer cells. Transient photocurrent and photovoltage measurements are used to probe the dynamics of charge‐separated carriers, with vastly different dynamic behavior observed for polymer/fullerene, polymer/polymer, and polymer/nanocrystal devices on the microsecond to millisecond timescale. Furthermore, by employing transient photocurrent analysis with different applied voltages we are also able to probe the dynamics behavior of these cells from short circuit to open circuit. P3HT/F8TBT and P3HT/CdSe devices are characterized by poor charge extraction of the long‐lived carriers attributed to charge trapping. P3HT/PCBM devices, in contrast, show relatively trap‐free operation with the variation in the photocurrent decay kinetics with applied bias at low intensity, consistent with the drift of free charges under a uniform electric field. Under solar conditions at the maximum power point, we see direct evidence of bimolecular recombination in the P3HT/PCBM device competing with charge extraction. Transient photovoltage measurements reveal that, at open circuit, photogenerated charges have similar lifetimes in all device types, and hence, the extraction of these long‐lived charges is a limiting process in polymer/nanocrystal and polymer/polymer devices.
Reduction of Tungsten Oxide: A Path Towards Dual Functionality Utilization for Efficient Anode and Cathode Interfacial Layers in Organic Light‐Emitting Diodes
Authors: Vasilopoulou Maria , Palilis Leonidas C. , Georgiadou Dimitra G. , Douvas Antonios M. , Argitis Panagiotis , Kennou Stella , Sygellou Labrini , Papadimitropoulos Georgios , Kostis Ioannis , Stathopoulos Nikos A. , Davazoglou Dimitris
Published: March 2011

Here, we report on the dual functionality of tungsten oxide for application as an efficient electron and hole injection/transport layer in organic light‐emitting diodes (OLEDs). We demonstrate hybrid polymer light‐emitting diodes (Hy‐PLEDs), based on a polyfluorene copolymer, by inserting a very thin layer of a partially reduced tungsten oxide, WO2.5, at the polymer/Al cathode interface to serve as an electron injection and transport layer. Significantly improved current densities, luminances, and luminous efficiencies were achieved, primarily as a result of improved electron injection at the interface with Al and transport to the lowest unoccupied molecular orbital (LUMO) of the polymer, with a corresponding lowering of the device driving voltage. Using a combination of optical absorption, ultraviolet spectoscopy, X‐ray photoelectron spectroscopy, and photovoltaic open circuit voltage measurements, we demonstrate that partial reduction of the WO3 to WO2.5 results in the appearance of new gap states just below the conduction band edge in the previously forbidden gap. The new gap states are proposed to act as a reservoir of donor electrons for enhanced injection and transport to the polymer LUMO and decrease the effective cathode workfunction. Moreover, when a thin tungsten oxide film in its fully oxidized state (WO3) is inserted at the ITO anode/polymer interface, further improvement in device characteristics was achieved. Since both fully oxidized and partially reduced tungsten oxide layers can be deposited in the same chamber with well controlled morphology, this work paves the way for the facile fabrication of efficient and stable Hy‐OLEDs with excellent reproducibility.
Lewis Acid‐Catalyzed Oxidative Allylation: A New Approach for the Synthesis of Homoallylic Alcohols and Amines Directly from Alcohols
Authors: Srivastava Vishnu P. , Patel Rajesh , Yadav Lal Dhar S.
Published: March 2011

A new approach for the synthesis of homoallylic alcohols and amines directly from alcohols via one‐pot sequential oxidation–Barbier reaction and oxidation–condensation–Barbier reactions, respectively, is reported. The protocol involves the one‐pot ferric chloride‐catalyzed oxidation of alcohols to the corresponding aldehydes with chloramine‐T followed by indium‐mediated Barbier allylation with allyl bromide to afford homoallylic alcohols in 70–90% overall yields. The ferric chloride‐catalyzed condensation of aldehydes and oxidation by‐product p‐toluenesulfonamide followed by indium‐mediated Barbier‐type allylation of the resulting aldimines with allyl bromide affords homoallylic amines in 60–80% overall yields in the same reaction vessel. The present work demonstrates a new one‐pot approach toward homoallylic alcohol and amine synthesis directly from alcohols.
A Stable Vanadium Redox‐Flow Battery with High Energy Density for Large‐Scale Energy Storage
Authors: Li Liyu , Kim Soowhan , Wang Wei , Vijayakumar M. , Nie Zimin , Chen Baowei , Zhang Jianlu , Xia Guanguang , Hu Jianzhi , Graff Gordon , Liu Jun , Yang Zhenguo
Published: March 2011

The all‐vanadium redox flow battery is a promising technology for large‐scale renewable and grid energy storage, but is limited by the low energy density and poor stability of the vanadium electrolyte solutions. A new vanadium redox flow battery with a significant improvement over the current technology is reported in this paper. This battery uses sulfate‐chloride mixed electrolytes, which are capable of dissolving 2.5 M vanadium, representing about a 70% increase in energy capacity over the current sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of −5 to 50 °C, potentially eliminating the need for electrolyte temperature control in practical applications. This development would lead to a significant reduction in the cost of energy storage, thus accelerating its market penetration.
Resting functional connectivity in patients with brain tumors in eloquent areas
Authors: Martino Juan , Honma Susanne M. , Findlay Anne M. , Guggisberg Adrian G. , Owen Julia P. , Kirsch Heidi E. , Berger Mitchel S. , Nagarajan Srikantan S.
Published: March 2011

Objective

Resection of brain tumors adjacent to eloquent areas represents a challenge in neurosurgery. If maximal resection is desired without inducing postoperative neurological deficits, a detailed knowledge of the functional topography in and around the tumor is crucial. The aim of the present work is to evaluate the value of preoperative magnetoencephalography (MEG) imaging of functional connectivity to predict the results of intraoperative electrical stimulation (IES) mapping, the clinical gold standard for neurosurgical localization of functional areas.

Methods

Resting‐state whole‐cortex MEG recordings were obtained from 57 consecutive subjects with focal brain tumors near or within motor, sensory, or language areas. Neural activity was estimated using adaptive spatial filtering algorithms, and the mean imaginary coherence between the rest of the brain and voxels in and around brain tumors were compared to the mean imaginary coherence between the rest of the brain and contralesional voxels as an index of functional connectivity. IES mapping was performed in all subjects. The cortical connectivity pattern near the tumor was compared to the IES results.

Results

Maps with decreased resting‐state functional connectivity in the entire tumor area had a negative predictive value of 100% for absence of eloquent cortex during IES. Maps showing increased resting‐state functional connectivity within the tumor area had a positive predictive value of 64% for finding language, motor, or sensory cortical sites during IES mapping.

Interpretation

Preoperative resting state MEG connectivity analysis is a useful noninvasive tool to evaluate the functionality of the tissue surrounding tumors within eloquent areas, and could potentially contribute to surgical planning and patient counseling. Ann Neurol 2011;69:–
Neuronal cell death in neonatal hypoxia‐ischemia
Authors: Northington Frances J. , Chavez‐Valdez Raul , Martin Lee J.
Published: March 2011

Perinatal hypoxic‐ischemic encephalopathy (HIE) is a significant cause of mortality and morbidity in infants and young children. Therapeutic opportunities are very limited for neonatal and pediatric HIE. Specific neural systems and populations of cells are selectively vulnerable in HIE; however, the mechanisms of degeneration are unresolved. These mechanisms involve oxidative stress, excitotoxicity, inflammation, and the activation of several different cell death pathways. Decades ago the structural and mechanistic basis of the cellular degeneration in HIE was thought to be necrosis. Subsequently, largely due to advances in cell biology and to experimental animal studies, emphasis has been switched to apoptosis or autophagy mediated by programmed cell death (PCD) mechanisms as important forms of degeneration in HIE. We have conceptualized based on morphological and biochemical data that this degeneration is better classified according to an apoptosis‐necrosis cell death continuum and that programmed cell necrosis has prominent contribution in the neurodegeneration of HIE in animal models. It is likely that neonatal HIE evolves through many cell death chreodes influenced by the dynamic injury landscape. The relevant injury mechanisms remain to be determined in human neonatal HIE, though preliminary work suggests a complexity in the cell death mechanisms greater than that anticipated from experimental animal models. The accurate identification of the various cell death chreodes and their mechanisms unfolding within the immature brain matrix could provide fresh insight for developing meaningful therapies for neonatal and pediatric HIE. Ann Neurol 2011;69:743–758
Nonisothermal curing of a solid resole phenolic resin
Authors: Zhou Da‐Peng , Du Siping , Yu Liqiong , Liu Zheng
Published: March 2011

A commercial solid resole phenolic resin was thoroughly characterized with Fourier transform infrared spectroscopy, NMR, and gel permeation chromatography, and its nonisothermal curing reaction was studied systematically with differential scanning calorimetry at a series of heating rates (βs) of 3, 4.5, 5.7, and 10°C/min. The results show that the solid resole had a higher molecular weight than conventional liquid resoles, and its reactive hydroxymethyl (CH2OH) and dibenzyl ether (CH2OCH2) functionalities participated in the crosslinking reaction upon heating. The nonisothermal curing reaction of the solid resole exhibited a relatively constant reaction heat, whereas the onset, peak, and end curing temperatures increased gradually with increasing βs. In addition, the reaction kinetics of the solid resole was analyzed with an nth‐order reaction model, the global activation energy was determined with the Kissinger method, and the reaction order was derived from the Crane equation. The obtained rate equation was applied to simulate the reaction time, conversion, and reaction rate, with a good fit achieved between the experimental data and the model predications. In conclusion, this study provided us with new knowledge on solid resoles at a molecular level and was also a great help for the curing procedure design, property optimization, and practical application of this commercial solid resole. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Properties of publications on anatomy in medical education literature
Authors: Vorstenbosch Marc , Bolhuis Sanneke , van Kuppeveld Sascha , Kooloos Jan , Laan Roland
Published: March 2011

Publications on anatomy in medical education appear to be largely anecdotal. To explore this, we investigated the literature on anatomy in medical education, aiming first to evaluate the contribution of the literature on anatomy in medical education to “best evidence medical education” (BEME) and second to evaluate the development of this literature toward more “best evidence” between 1985 and 2009. Four databases were searched for publications on anatomy in medical education published between 1985 and 2009, resulting in 525 references. Hundred publications were characterized by five variables (journal category, paper subject, paper category, author perspective, and paper perspective). Statements from these publications were characterized by two variables (category and foundation). The publications contained 797 statements that involved the words “anatomy,” “anatomical,” or “anatomist.” Forty‐five percent of the publications contained no explicit research question. Forty percent of the statements made were about “teaching methods” and 17% about “teaching content,” 8% referred to “practical value,” and 10% to “side effects” of anatomy education. Ten percent of the statements were “positional,” five percent “traditional,” four percent “self‐evident,” and two percent referred to “quality of care.” Fifty‐six percent of the statements had no foundation, 17% were founded on empirical data, and 27% by references. These results substantiated the critical comments about the anecdotal nature of the literature. However, it is encouraging to see that between 1985 and 2009 the number of publications is rising that these publications increasingly focus on teaching methods and that an academic writing style is developing. This suggests a growing body of empirical literature about anatomy education. Anat Sci Educ 4: 105–114, 2011. © 2011 American Association of Anatomists
Pseudoganglion on the connecting branch between the deep branch of the lateral plantar nerve and medial plantar nerve
Authors: Arakawa Takamitsu , Sekiya Shin‐Ichi , Terashima Toshio , Miki Akinori
Published: March 2011

The connecting branch between the deep branch of the lateral plantar nerve and medial plantar nerve often has an enlarged site. We investigated these enlarged sites of the connecting branches. We observed the 22 human feet of 20 Japanese cadavers. We investigated the connecting branch macroscopically and histologically. We found the connecting branches between the deep branch of the lateral plantar nerve and medial plantar nerve in 19 feet out of 22 feet. This connecting nerve branch was interposed between the tendon of the flexor hallucis longus and the flexor hallucis brevis, and there enlarged in the anteroposterior direction. After penetration, numbers of fascicles of this connecting branch were increased at the enlarged site. In this region, the connective tissues surrounding the nerve fascicles and vessels were more developed compared with the adjoining sides of this branch. A few fascicles at this enlarged site innervated the first metatarsophalangeal joint capsule. Other nerve fascicles arose from the connecting branch and branched off muscular branches to the flexor hallucis brevis. This branch possibly receives the physical exertion or friction during gait due to its position. Deformity and overload of the foot can cause sensory disorders of the foot, but the anatomical basis for the relationship between the deformity/overload and sensory disorders of the foot is unclear. We discussed that this connecting branch can be a potential cause of pressure neuropathies in the human foot. Clin. Anat. 24:646–651, 2011. © 2011 Wiley‐Liss, Inc.
Eukaryotic elongation factor‐2 (eEF2): its regulation and peptide chain elongation
Authors: Kaul Gautam , Pattan Gurulingappa , Rafeequi Towseef
Published: March 2011

Regulation at the level of translation in eukaryotes is feasible because of the longer lifetime of eukaryotic mRNAs in the cell. The elongation stage of mRNA translation requires a substantial amount of energy and also eukaryotic elongation factors (eEFs). The important component of eEFs, i.e. eEF2 promotes the GTP‐dependent translocation of the nascent protein chain from the A‐site to the P‐site of the ribosome. Mostly the eEF2 is regulated by phosphorylation and dephosphorylation by a specific kinase known as eEF2 kinase, which itself is up‐regulated by various mechanisms in the eukaryotic cell. The activity of this kinase is dependent on calcium ions and calmodulin. Recently it has been shown that the activity of eEF2 kinase is regulated by MAP kinase signalling and mTOR signalling pathway. There are also various stimuli that control the peptide chain elongation in eukaryotic cell; some stimuli inhibit and some activate eEF2. These reports provide the mechanisms by which cells likely serve to slow down protein synthesis and conserve energy under nutrient deprived conditions via regulation of eEF2. The regulation via eEF2 has also been seen in mammary tissue of lactating cows, suggesting that eEF2 may be a limiting factor in milk protein synthesis. Regulation at this level provides the molecular understanding about the control of protein translocation reactions in eukaryotes, which is critical for numerous biological phenomenons. Further the elongation factors could be potential targets for regulation of protein synthesis like milk protein synthesis and hence probably its foreseeable application to synthetic biology. Copyright © 2011 John Wiley & Sons, Ltd.
Angiographic outcomes with biodegradable polymer and permanent polymer drug‐eluting stents
Authors: Kufner Sebastian , Massberg Steffen , Dommasch Michael , Byrne Robert A. , Tiroch Klaus , Ranftl Sabine , Fusaro Massimiliano , Schömig Albert , Kastrati Adnan , Mehilli Julinda ,   for the Intracoronary Stenting and Angiographic Results: Test Efficacy of 3 Limus‐Eluting Stents (ISAR‐TEST‐4) Trial Investigators
Published: March 2011

Background: In the Intracoronary Stenting and Angiographic Results: Test Efficacy of 3 Limus‐Eluting Stents (ISAR‐TEST‐4) trial, we demonstrated the noninferiority of biodegradable polymer (BP) sirolimus‐eluting stent to permanent polymer (PP) sirolimus/everolimus‐eluting stent (Cypher/Xience‐V) on the basis of clinical outcomes. In this study, we compare the antirestenotic efficacy of these stents in ISAR‐TEST‐4 patients with paired angiographic studies. Methods: Patients with de novo coronary lesions in native vessels (excluding left main lesions) were randomly assigned to receive a BP stent or a PP stent. Endpoints of interest of this study were in‐stent late lumen loss, in‐segment binary restenosis, and restenosis morphology at 6–8‐month follow‐up angiogram. Results: Of the 2,603 patients (3,372 lesions) enrolled in ISAR TEST‐4 trial, 2,016 patients (2,637 lesions) underwent repeat angiographic examination 6–8 months after randomization: 1,006 patients (1,323 lesions) treated with BP stents and 1,010 patients (1,314 lesions) treated with PP stents. No difference was observed between BP and PP stents in in‐stent late lumen loss (0.24 ± 0.6 vs. 0.26 ± 0.5 mm, respectively, P = 0.49) or in in‐segment binary restenosis (11.6% [153 lesions] vs. 11.8% [155 lesions], P = 0.85). Focal pattern of restenosis was observed in the majority of patients receiving either BP or PP stents. The diffuse pattern of restenosis was observed in 26.8% of patients treated with BP stent and 26.5% of patients treated with PP stent (P = 0.79). Conclusion: Angiographic characteristics of restenosis after BP‐based limus‐eluting stents are similar to those of PP‐based limus‐eluting stents. © 2011 Wiley‐Liss, Inc.
Prediction of the Profit Function for Industrial 2‐Keto‐L‐Gulonic Acid Cultivation
Authors: Cui L. , Xu Y. , Jia Q. , Wu H. , Yuan J.
Published: March 2011

The profit function is the generic criterion to describe the cost effect of a batch process. To focus on the prediction of the profit function for 2‐keto‐L‐gulonic acid (2‐KGA) cultivation, which is potentially applicable for process monitoring and optimal scheduling, rolling learning‐prediction (RLP) based on a support vector machine (SVM) is applied. The RLP implies that the SVM training database is rolling updated as the batch of current interest proceeds, and the SVM learning is then repeated for the prediction. The database is further updated after termination of a batch. The updating procedures are investigated in detail. Pseudo‐online prediction is carried out using the data from industrial‐scale 2‐KGA cultivation under actual and hypothetical inoculation sequences. The results indicate that the average relative prediction error is less than 5 % in the later phase of fermentation in all inoculation sequences.
Synthesis and Antioxidant Activity of Peptide‐Based Ebselen Analogues
Authors: Satheeshkumar Kandhan , Mugesh Govindasamy
Published: March 2011

A series of di‐ and tripeptide‐based ebselen analogues has been synthesized. The compounds were characterized by 1H, 13C, and 77Se NMR spectroscopy and mass spectral techniques. The glutathione peroxidase (GPx)‐like antioxidant activity has been studied by using H2O2, tert‐butyl hydroperoxide (tBuOOH), and cumene hydroperoxide (Cum‐OOH) as substrates, and glutathione (GSH) as a cosubstrate. Although all the peptide‐based compounds have a selenazole ring similar to that of ebselen, the GPx activity of these compounds highly depends on the nature of the peptide moiety attached to the nitrogen atom of the selenazole ring. It was observed that the introduction of a phenylalanine (Phe) amino acid residue in the N‐terminal reduces the activity in all three peroxide systems. On the other hand, the introduction of aliphatic amino acid residues such as valine (Val) significantly enhances the GPx activity of the ebselen analogues. The difference in the catalytic activity of dipeptide‐based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide. Although the presence of the Val‐Ala‐CO2Me moiety facilitates the formation of a catalytically active selenol species, the reaction of ebselen analogues that has a Phe‐Ile‐CO2Me residue with GSH does not generate the corresponding selenol. To understand the antioxidant activity of the peptide‐based ebselen analogues in the absence of GSH, these compounds were studied for their ability to inhibit peroxynitrite (PN)‐mediated nitration of bovine serum albumin (BSA) and oxidation of dihydrorhodamine 123. In contrast to the GPx activity, the PN‐scavenging activity of the Phe‐based peptide analogues was found to be comparable to that of the Val‐based compounds. However, the introduction of an additional Phe residue to the ebselen analogue that had a Val‐Ala dipeptide significantly reduced the potency of the parent compound in PN‐mediated nitration.
Inverse Exergoecological and Economical Analysis of Gas Treatment Processes
Authors: Schöneberger Jan C. , Arellano‐Garcia Harvey , Wozny Günter
Published: March 2011

Bei allen Prozessen der Energie‐ oder der Verfahrenstechnik, in denen aus Rohstoffen höherwertige Produkte erzeugt werden, müssen Exergie und Kapital aufgebracht werden. Die exergo‐ökonomische Analyse zeigt, welche Kosten mit der Vernichtung von Exergie verbunden sind. Bei der Betrachtung von Abgasbehandlungsprozessen ergeben sich Widersprüche, da diese Prozesse häufig weder aus wirtschaftlicher noch aus energetischer Sicht sinnvoll sind, sondern aus Gründen des Umweltschutzes durchgeführt werden. Das neue Konzept der exergo‐ökonomisch‐ökologischen Prozessanalyse wird vorgestellt und auf Prozesse zur Behandlung schwefelwasserstoffhaltiger Abgase angewandt. Dabei zeigt sich, wie durch diese systematische Analyse Verbesserungspotenziale aufgedeckt werden können.
Erratum: Trace Elements in Sediments and Mussels – Spatial Distribution, Chemical Partitioning, and Risk Assessment
Authors: Khairy Mohammed A. , Kolb Marit , Schmidt Christiane , Zachmann Dieter W. , Mostafa Alaa R. , EL‐Fiky Anwar A. , Bahadir Müfit
Published: March 2011

Sediment samples were collected from 30 different locations in Abu Qir Bay (Mediterranean Sea), East Alexandria, Egypt and analyzed for trace elements. The highest concentrations of most of the elements were observed in the nearshore stations in the vicinity of the major anthropogenic activities as industrial settlements, wastewater discharges, and agricultural drainage. In addition, mussel samples of Mactra corallina and Tapes decussata were collected corresponding to the sediment samples. Concentrations of As, Cd, Cr, Mn, and Zn in the mussel tissues were higher than concentrations in sediments, thus indicating their relatively high bioavailability. Sequential extraction procedure was performed on selected sediment samples. Significant correlations were observed between the concentrations of Cu, Mn, Pb, and Zn in the exchangeable fraction of the sediments and the corresponding tissues of M. corallina. The output of the risk assessment applied on the sediments revealed that adverse ecological effects to benthic species could occur and that a higher level of risk is expected from the exposure to Cd, Cr, Hg, and Zn. No adverse carcinogenic or non‐carcinogenic human health effects are expected from the consumption of the two mussel species from Abu Qir Bay.
Upfront observation versus radiation for adult pilocytic astrocytoma
Authors: Ishkanian Adrian , Laperriere Normand J. , Xu Wei , Millar Barbara‐Ann , Payne David , Mason Warren , Sahgal Arjun
Published: March 2011

BACKGROUND:

Although pilocytic astrocytoma accounts for up to 40% of all childhood brain tumors, it is a rare disease in adults. Consequently, there are few mature data on the impact of up‐front treatment options after surgery that include observation or adjuvant radiotherapy.

METHODS:

Ten women and 20 men were identified who were diagnosed with pilocytic astrocytoma from 1971 to 2007 and were retrospectively reviewed. The median patient age was 30 years (range, 18‐64 years), and the median follow‐up was 87 months (range, 16‐420 months). Initial surgery included biopsy (10% of patients), subtotal resection (57% of patients), or gross‐total resection (33% of patients). Nineteen patients were observed postoperatively, whereas 11 patients received up‐front postoperative adjuvant radiotherapy (50 grays in 25 fractions). No patient received adjuvant or concurrent chemotherapy. Progression‐free survival (PFS) and overall survival (OS) were calculated using the Kaplan‐Meier method. Differences between survival curves were analyzed with the log‐rank test.

RESULTS:

For the entire cohort, the 5‐year and 10‐year OS rates were 95% and 85%, respectively, and the 5‐year and 10‐year PFS rates were 63% and 35%, respectively. The median PFS was 8.4 years. Initial radiation, compared with observation, did not have an impact on OS but significantly improved PFS. The 5‐year PFS rate for patients who were observed versus those who received radiation was 42% versus 91%, respectively; and, at 10 years, the PFS rate was 17% versus 60%, respectively (P = .005). Patients who progressed after observation (11 of 19 patients) received various salvage therapies, resulting in a 2‐year PFS rate of 68% compared with 33% for patients who progressed after initial radiation (3 of 11 patients) and were salvaged with either chemotherapy or surgery (P = .1).

CONCLUSIONS:

Adjuvant radiotherapy for pilocytic astrocytoma significantly prolonged PFS at both 5 years and 10 years compared with observation. However, equivalent OS was observed, which reflected the efficacy of salvage therapies. Cancer 2011;. © 2011 American Cancer Society.
Cervical (pap) smear: New directions
Authors: Koss Leopold G.
Published: March 2011

This article reports the historic background leading to the introduction of cervical smears as a tool in the detection of precancerous changes in the uterine cervix. The false‐negative error rate in the primary screening process is discussed and illustrated by data recently compiled from this laboratory. Rescreening of approximately 25% of cervical smears yielded an error screening rate of approximately 5% of precancerous lesions and cancer of the uterine cervix. The total false‐negative screening error rate was much higher but was unknown and should be determined by additional studies. The reasons for the false‐negative screening errors are discussed. Some of the proposed remedies, particularly screening of the entire population for human papillomavirus infection, are judged to be unacceptable because of the high prevalence of this virus in well women and because the biologic events linking the presence of viral DNA with the development of precancerous lesions are unknown. Screening assistance with the help of a newly developed interactive machine, combining image analysis with a neural net was promising as a tool in quality control.
New approaches to high‐risk cervical cancer: Advanced cervical cancer
Authors: Jones Walter B.
Published: March 2011

Background. The role of chemotherapy in the surgical management of high‐risk cervical cancer has not yet been defined. Based on the ability of numerous cytotoxic agents to induce regressions in advanced and recurrent cervical cancer, there is now a trend toward early use of these drugs. The efficacy of cisplatin‐containing regimens in particular suggests that new strategies combining chemotherapy and surgery may result in improved survival rates in patients with high‐risk cervical cancer.

Methods. In this review of the literature, two groups of patients who may benefit from this approach to therapy are discussed. In the first group are patients with local or regionally advanced cervical carcinoma who receive chemotherapy (neoadjuvant) with the goal of reducing tumor bulk and thus allowing surgical treatment in normally inoperable cases. The second group consist of patients with identifiable adverse risk factors after radical hysterectomy and pelvic lymphadenectomy who receive postoperative chemotherapy (adjuvant) in an effort to decrease local and distant recurrences.

Results. The administration of neoadjuvant chemotherapy to patients with local and locally advanced cervical cancer allows radical surgery to be performed in many patients who otherwise would be considered inoperable. In these patients, there also appears to be a decrease in the incidence of pelvic and distant recurrences and possibly an improvement in survival rates. Adjuvant chemotherapy after radical surgery for patients at high risk for recurrence appears to provide a survival advantage in some high‐risk patients.

Conclusions. Preliminary results in the new approaches to therapy that combine chemotherapy with surgery in patients with high‐risk cervical cancer are encouraging. Randomized prospective trials are warranted to identify the most active chemotherapeutic regimens and to determine the patient selection criteria most likely to result in improved survival rates.
Endometrial carcinoma: Influence of prognostic factors on radiation management
Authors: Rotman Marvin , Aziz Hassan , Halpern Joshua , Schwartz David , Sohn Chul , Choi Kwang
Published: March 2011

The earliest intracavitary radium treatment for uterine cancer was reported in 1908. Refinements reported during the next 20 years, using an intrauterine tube and colpostats or radium capsules, established a treatment philosophy of preoperatively irradiating uterine and parauterine tissues. Thus, preoperative intracavitary irradiation became entrenched as therapy for all endometrial cancers for the better part of four decades. In the 1950s and 1960s, the ability of external irradiation to eradicate cancer in regional lymphatic vessels prompted the use of pelvic field irradiation in Stage II and III and recurrent disease. The results of surgical exploratory studies in the 1970s established more refined criteria for preoperative or postoperative external pelvic irradiation in high‐grade infiltrating Stage I cancers. In the 1980s, it became apparent that, for tumors with lymphovascular invasion, clear cell, and serous papillary histologic types, the disease spread to the upper abdomen and the paraaortic nodes might benefit from extended field and/or whole abdominal irradiation, with or without systemic bolus or concomitant continuous‐infusion chemotherapy. In the 1980s, a subset of patients was identified with high‐grade lymphovascular invasion clear cell and papillary serous histologic types or with positive peritoneal cytologic findings who were at high risk of failing in the paraaortic nodes and/or the upper abdomen for whom extended field or whole abdominal irradiation have been advocated. Given the fraction and dose limitation for a large abdominal field, the addition of systemic concomitant bolus or continuous infusion of chemotherapy currently is proposed to improve the control of intraabdominal failure in these high‐risk patients.
Epidemiology of breast cancer: Findings from the nurses' health study
Authors: Colditz Graham A.
Published: March 2011

Background. The epidemiology of breast cancer was reviewed in the context of hormonal, hereditary, histologic, and dietary risk factors.

Methods. Literature review.

Results. Late age at menarche and early age at first birth decrease the risk of breast cancer as does an early age at menopause. These risk factors relate to the lifetime exposure of the breast tissue to ovarian hormones. Although an early first birth is associated with a transient increase in the risk of breast cancer, perhaps as a result of the breast's exposure to high levels of hormones before terminal differentiation, in older women, parity is associated with a decreased risk of breast cancer. Among postmenopausal women, obesity is associated with higher levels of estrogens and an increased risk of breast cancer. Within the strata of breast cancer stages at diagnosis, obesity is associated with increased mortality, again supporting the influence of endogenous estrogens on this disease's incidence, recurrence, and survival rates. Consistent with these relationships, current use of estrogen therapy among postmenopausal women is associated with an increased risk of breast cancer. A family history of breast cancer is associated with approximately a twofold increase in the risk of breast cancer, and this risk is greater if the diagnosis was made when the woman's mother was young, although even a diagnosis in an older mother is associated with an increased risk in her daughters. The follow‐up of women with a history of benign breast biopsy results shows that atypical hyperplasia is associated with a fourfold increase in risk compared with a biopsy specimen without proliferative changes. Atypia doubles the risk. These data support the concept of atypia as a precursor lesion for breast cancer and may warrant its use as a marker in further studies. Consistent data from retrospective and prospective studies show a positive association between moderate alcohol intake and the risk of breast cancer. This may reflect the increase in estrogen levels observed among women who consume alcohol. Data from prospective studies do not support a relationship between dietary fat intake and the risk of breast cancer either in premenopausal or postmenopausal women.

Conclusions. Few of these associations offer the potential for intervention to reduce the breast cancer risk.
Breast cancer: Challenge and responsibility
Authors: Marchant Douglas J.
Published: March 2011

The diagnosis and treatment of breast cancer has changed dramatically during the last quarter century, a fact perhaps not fully appreciated by many primary care physicians.

Breast cancer presents a number of challenges for the obstetrician/gynecologist. The disease is common and the mortality rate is second only to lung cancer. The appropriate role for the obstetrician/gynecologist is one of surveillance, including taking a history and physical examination and selected diagnostic studies, and as a resource for patients, including a discussion of risk factors and treatment alternatives.

Because of the increasing involvement of obstetrics and gynecology in molecular genetics and hormone interactions, basic research in genetic alterations and hormonal therapy directed toward decreasing morbidity from cardiovascular disease and osteoporosis is recommended.