bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric ions and nucleation: a review of observations
Authors: Hirsikko A. , Nieminen T. , Gagné S. , Lehtipalo K. , Manninen H. E. , Ehn M. , Hõrrak U. , Kerminen V. -M. , Laakso L. , McMurry P. H. , Mirme A. , Mirme S. , Petäjä T. , Tammet H. , Vakkari V. , Vana M. , Kulmala M.
Published: October 2010

Abstract. This review is based on ca. 250 publications, from which 92 published data on the temporal and spatial variation of the concentration of small ions (<1.6 nm in diameter) in the atmosphere, chemical composition, or formation and growth rates of sub-3 nm ions. The small ions exist all the time in the atmosphere, and the average concentrations of positive and negative small ions are typically 200–2500 cm−3. However, concentrations up to 5000 cm−3 have been observed. The results are in agreement with observations of ion production rates in the atmosphere. Concentrations of small ions increased in the early morning hours due to night time inversion, which leads to accumulation of radon. We also summarised observations on the conversion of small ions to intermediate ions, which can act as embryos for new atmospheric aerosol particles. Those observations include the formation rates (J2[ion]) of 2-nm intermediate ions, growth rates (GR[ion]) of sub-3 nm ions, and information on the chemical composition of the ions. Unfortunately, there were only a few studies which presented J2[ion] and GR[ion]. Based on the publications, the formation rates of 2-nm ions were 0–1.1 cm−3 s−1, while the total 2-nm particle formation rates varied between 0.001 and 60 cm−3 s−1. The ion-mediated processes were observed to dominate when the total particle formation rates were small, and, accordingly the importance of ion-induced mechanisms decreased with increasing total 2-nm particle formation rates. Furthermore, small ions were observed to activate for growth earlier than neutral nanometer-sized particles and at lower saturation ratio of condensing vapours.
A theoretical study on UV-spectroscopy, electronic structure and reactivity properties of sesquiterpenes
Authors: Hu S.-X. , Yu J.-G. , Zeng E. Y.
Published: October 2010

Abstract. Sesquiterpenes, a class of biogenic volatile organic compounds, are important precursors to secondary organic aerosols (SOAs) in nature. Using density functional theory (DFT), conceptual DFT, time-dependent (TD) DFT, configuration interaction with single excitation (CIS), and Zerner's intermediate neglect of differential overlap (ZINDO) methods, the electronic structures, spectroscopy, and reactivity of sesquiterpenes were systematically investigated. Results from the CIS calculations show the best consistency in the excited energies and allow for assigning and predicting newly found sesquiterpenes. The results suggest that the first peaks in the ultraviolet-visible (UV-vis) absorption spectra for saturated and unsaturated isomers are σ–σ* and π–π* transitions, respectively. It can be deduced from the transit intensities of the isomers that an isomer with an endocyclic C = C bond presents weaker UV transition intensity than its corresponding exocyclic isomer. The electronic structures of these compounds were also analyzed by comparing published UV-spectroscopy with advanced theoretical calculations. α-Zingiberene and longicyclene are the most and least reactive in electron-transfer reactions, respectively. No quantitative linear relationships were discovered between the changes in transit energies, DFT chemical reactivity indices of isomers, different degrees of unsaturated C = C double bonds, or the number of substituents attached to the C = C bond. The larger steric hindrance of substituents or exocyclic C = C bond is related directly to higher chemical reactivity possessed by the isomer compared to a corresponding isomer with smaller steric hindrandce or with an endo C = C bond. These results are imperative to a better understanding of SOA production mechanisms in the troposphere.
Environmental change within the Balkan region during the past ca. 50 ka recorded in the sediments from lakes Prespa and Ohrid
Authors: Wagner B. , Vogel H. , Zanchetta G. , Sulpizio R.
Published: October 2010

Abstract. Lakes Prespa and Ohrid, in the Balkan region, are considered to be amongst the oldest lakes in Europe. Both lakes are hydraulically connected via karst aquifers. From Lake Ohrid, several sediment cores up to 15 m long have been studied over the last few years. Here, we document the first long sediment record from nearby Lake Prespa to clarify the influence of Lake Prespa on Lake Ohrid and the environmental history of the region. Radiocarbon dating and dated tephra layers provide robust age control and indicate that the 10.5 m long sediment record from Lake Prespa reaches back to 48 ka. Glacial sedimentation is characterized by low organic matter content and absence of carbonates in the sediments, which indicate oligotrophic conditions in both lakes. Holocene sedimentation is characterized by particularly high carbonate content in Lake Ohrid and by particularly high organic matter content in Lake Prespa, which indicates a shift towards more mesotrophic conditions in the latter. Long-term environmental change and short-term events, such as related to the Heinrich events during the Pleistocene or the 8.2 ka cooling event during the Holocene, are well recorded in both lakes, but are only evident in certain proxies. The comparison of the sediment cores from both lakes indicates that environmental change affects particularly the trophic state of Lake Prespa due to its lower volume and water depth.
Carbon allocation to biomass production of leaves, fruits and woody organs at seasonal and annual scale in a deciduous- and evergreen temperate forest
Authors: Campioli M. , Gielen B. , Granier A. , Verstraeten A. , Neirynck J. , Janssens I. A.
Published: October 2010

Abstract. Carbon taken up by the forest canopy is allocated to tree organs for biomass production and respiration. Because tree organs have different life span and decomposition rate, the tree C allocation determines the residence time of C in the ecosystem and its C cycling rate. The study of the carbon-use efficiency, or ratio between net primary production (NPP) and gross primary production (GPP), represents a convenient way to analyse the C allocation at the stand level. Previous studies mostly focused on comparison of the annual NPP-GPP ratio among forests of different functional types, biomes and age. In this study, we extend the current knowledge by assessing (i) the annual NPP-GPP ratio and its interannual variability (for five years) for five tree organs (leaves, fruits, branches, stem and coarse roots), and (ii) the seasonal dynamic of NPP-GPP ratio of leaves and stems, for two stands dominated by European beech and Scots pine. The average NPP-GPP ratio for the beech stand (38%) was similar to previous estimates for temperate deciduous forests, whereas the NPP-GPP ratio for the pine stand (17%) is the lowest recorded till now in the literature. The proportion of GPP allocated to leaf NPP was similar for both species, whereas beech allocated a remarkable larger proportion of GPP to wood NPP than pine (29% vs. 6%, respectively). The interannual variability of the NPP-GPP ratio for wood was substantially larger than the interannual variability of the NPP-GPP ratio for leaves, fruits and overall stand and it is likely to be controlled by previous year air temperature (both species), previous year drought intensity (beech) and thinning (pine). Seasonal pattern of NPP-GPP ratio greatly differed between beech and pine, with beech presenting the largest ratio in early season, and pine a more uniform ratio along the season. For beech, NPP-GPP ratio of leaves and stems peaked during the same period in the early season, whereas they peaked in opposite periods of the growing season for pine. Seasonal differences in C allocation are likely due to functional differences between deciduous and evergreen species and temporal variability of the sink strength. The similar GPP and autotrophic respiration between stands and the remarkable larger C allocation to wood at the beech stand indicate that at the beech ecosystem C has a longer residence time than at the pine ecosystem. Further research on belowground production and particularly on fine roots and ectomycorrhizal fungi likely represents the most important step to progress our knowledge on C allocation dynamics.
Responses of snowmelt runoff to climatic change in an inland river basin, Northwestern China, over the past 50 years
Authors: Wang J. , Li H. , Hao X.
Published: October 2010

Abstract. The spatial and temporal variations of snowcover distribution, and snowmelt runoff are considered as sensitive indicators for climatic change. The purpose of this paper is to analyze and forecast the responses of snowmelt runoff to climate change in an inland river basin. The upper basin of Heihe River in Northwestern China was chose as the study area, and the observation data from the meteorological and hydrological stations were utilized to analyze the status and regularity of the climatic change over the past 50 years. Snow cover area was obtained by an optimized technology using Moderate Resolution Imaging Spectroradiometer data with Normalized Difference Snow Index adjustment and topographic correction. A concept of potential snowmelt was suggested to illustrate the response of spatial snowmelt to climate change. The results show that the annual SCA proportion and the potential snowmelt keep an increasing trend since 2000. There is a negative relationship between annual air temperature and SCA proportion from 2000 to 2008. Snowmelt Runoff Model was chose to simulate snowmelt runoff and scenario forecast the change trend of snowmelt runoff in this region. The results show that climatic warming was apparent in the upper basin of Heihe River over the past 50 a. Annual average air temperature of three different weather stations located in the basin has increased 2.1 °C, 2.6 °C and 2.9 °C respectively from 1956 to present. The snowmelt runoff has increased obviously from 1970 to present. With different warming climate scenarios, the results by using SRM simulating showed that the first occurred time of snowmelt runoff shift ahead and discharge become larger as responses of snowmelt runoff to air temperature increasing, and the influence of temperature rising on average discharge of the whole snow season is not obvious.
Thermoresponsive shape memory characteristics of polyurethane electrospun web
Authors: Chung Seung Eun , Park Chung Hee , Yu Woong‐Ryeol , Kang Tae Jin
Published: October 2010

Electrospun web (ESW) was manufactured and its performance was evaluated to investigate its applicability as an intelligent clothing material using shape memory polymers. Mixtures of various compositions were applied to make the shape memory polyurethane (SMPU) films and the polyurethane with the best shape memory performance was then selected to make the ESWs. The structural and thermal properties, as well as the shape memory behavior were evaluated. The air permeability, the water vapor transmission, and the water resistance were measured. The ESW having a high orientation due to an elongation in the process of the electrospinning showed a higher melting point than the film and its shape recovery was improved. The ESW showed a good moisture and air permeability due to the fact that its structural characteristics incorporate countless nano‐sized pores. Because of this, the ESW maintained in its expanded state below the transition temperature showed improved moisture and air permeabilities. Therefore, it can be concluded that the SMPU web proved to have potential for intelligent clothing material. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation of raspberry‐like poly(methyl methacrylate) particles by seeded dispersion polymerization
Authors: Shi Shan , Zhou Limin , Wang Tao , Bian Lina , Tang Yantao , Kuroda Shin‐ichi
Published: October 2010

The facile preparation of nonspherical raspberry‐like poly(methyl methacrylate) (PMMA) particles by seeded dispersion polymerization of methyl methacrylate (MMA) on micron‐sized PMMA seed particles was described. Various polymerization parameters influencing the particle morphology, as well as the polymerization kinetic and morphological stability, were investigated in detail. It was found that the following polymerization conditions were necessary to prepare this kind of nonspherical particles: a relatively low temperature, an appropriate ratio of seed/MMA, an initiator with a relatively low decomposition rate, and a relatively low initiator concentration. These particles showed very good morphological stability at room temperature, but they changed to the spherical ones when heat treated at 60°C in methanol solution of MMA. The experimental results suggest that the prepared PMMA particles were kinetically favored and the localized polymerization of the MMA monomer on PMMA seed particle surface was responsible for the formation of the raspberry‐like particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Degradation of poly(D,L‐lactic acid)‐b‐poly(ethylene glycol) copolymer and poly(L‐lactic acid) by electron beam irradiation
Authors: Miao Peikai , Wu Dimeng , Zeng Ke , Zhao Chun'e , Xu Guoliang , Huang Zhifu , Yang Gang
Published: October 2010

This article investigated the effects of electron beam (EB) irradiation on poly(D,L‐lactic acid)‐b‐poly(ethylene glycol) copolymer (PLEG) and poly(L‐lactic acid) (PLLA). The dominant effect of EB irradiation on both PLEG and PLLA was chain scission. With increasing dose, recombination reactions or partial crosslinking of PLEG can occur in addition to chain scission, but there was no obvious crosslinking for PLLA at doses below 200 kGy. The chain scission degree of irradiated PLEG and PLLA was calculated to be 0.213 and 0.403, respectively. The linear relationships were also established between the decrease in molecular weight with increasing dose. Elongation at break of the irradiated PLEG and PLLA decreased significantly, whereas the tensile strength and glass transition temperature of PLLA decreased much more significantly compared with PLEG. The presence of poly(ethylene glycol) (PEG) chain segment in PLEG was the key factor in its greater stability to EB irradiation compared with PLLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of stereoregularity and molecular weight on the mechanical properties of poly(vinyl alcohol) hydrogel
Authors: Fukae Ryohei , Yoshimura Miki , Yamamoto Tohei , Nishinari Katsuyoshi
Published: October 2010

The effect of the stereoregularity and molecular weight of poly(vinyl alcohol) (PVA) on the mechanical properties of hydrogel was investigated. Compressive strength, creep behavior, and dynamic viscoelasticity were measured on hydrogels of syndiotacticity‐rich PVA derived from poly(vinyl pivalate) (Dp = 1690 diad‐syndiotacticity = 61%, Dp = 8020 diad‐syndiotacticity = 62%) and atactic PVA (Dp = 1750 diad‐syndiotacticity = 54%, Dp = 7780 diad‐syndiotacticity = 54%). Increasing the molecular weight of molecular chains constituting the gel improved the compressive strength of atactic PVA hydrogel. The stereoregularity of PVA had a greater effect than molecular weight on the strength of the hydrogel. Gel prepared from 8.8 g/dL syndiotacticity‐rich PVA had a high compressive modulus of 10 kPa, and the compressive modulus of the gel prepared from 3.3 g/dL was comparable with that of atactic PVA hydrogel prepared with more than 6 g/dL. The dynamic storage modulus of the gel derived from syndiotacticity‐rich PVA was remarkably higher than that of the atactic PVA gel and remained constant up to 60°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Post and prepolymerization strategies to develop novel photochromic poly(esterimide)s
Authors: Schab‐Balcerzak Ewa , Siwy Mariola , Jarzabek Bozena , Kozanecka‐Szmigiel Anna , Switkowski Krzysztof , Pura Bronisław
Published: October 2010

This paper reports novel photoresponsive, processable poly(esterimide)s functionalized with the azobenzene and tricyanovinylene groups. Post and prepolymerization strategies were utilized for preparation of the new photochromic polymers with imide rings. The postpolymerization method of azopolymer synthesis included a functionalization of precursor poly(esterimide) containing dialkylaminophenyl groups with diazonium salt of aniline. The precursor poly(esterimide) was obtained from synthesized 2,2′[N‐phenylethyloaniline‐di(4‐estro‐1,2‐dicarboxylic)]anhydride and 4,4′‐methylene bis(2,6‐dimethylaniline). The prepolymerization strategy based on polycondesation of 2,4‐diaminoazobenzene with two dianhydrides, that is, with or without the azobenzene group. The new dianhydride with azobenzene unit was obtained. The reaction of post‐tricyanovinylation was carried out for substitution of prepared polymers with tricyanovinylene groups. The synthesized polymers were characterized and evaluated by FTIR, 1H NMR, X‐ray, UV‐Vis spectroscopies, and DSC. The polymers exhibited glass transition temperatures in the range of 119–208°C and good solubilities in common organic solvents, providing optical‐quality films. Thermal stability of the polymers films was investigated by UV‐Vis spectroscopy. Preliminary investigations of the optical anisotropy in chosen poly(esterimide)s were carried out by photoinduced birefringence measurements. Relatively high photoinduced birefringence (Δn = 0.01) was measured for polyimide with covalently bonded azobenzene substituted with strong acceptor group. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of applied voltage on diameter and morphology of ultrafine fibers in bubble electrospinning
Authors: Liu Yong , Dong Liang , Fan Jie , Wang Rui , Yu Jian‐Yong
Published: October 2010

A novel electrospinning process, bubble electrospinning, was used to produce porous nonwoven fibrous mats, of which the fiber diameter can range from nano‐ to microscales. The deformation of a charged bubble, from which multiple jets were ejected, was observed using a high‐speed motion camera. The effects of different applied voltages on diameter, morphology, and structure of bubble‐electrospun ultrafine fibers were theoretically analyzed and then experimentally validated by scanning electron microscopy and atomic force microscopy. The results showed that the average diameter of fibers increased with the increase of the applied voltage in bubble electrospinning, which is quite different from that in traditional electrospinning process under the similar conditions. The number of beaded fibers decreased with increasing applied voltage. Additionally, the crystallinities of polyvinylpyrrolidone ultrafine fibers obtained in this process were higher than that of polyvinylpyrrolidone powders. The production rate of bubble electrospinning was higher than that of the traditional electrospinning. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and properties of nonionic polyol dispersion from terpinene‐maleic ester‐type epoxy resin
Authors: Wu Guo‐Min , Kong Zhen‐Wu , Chen Jian , Jiang Jian‐Chun
Published: October 2010

A nonionic epoxy‐based polyol (NTP) which can be used in place of the commonly used polyol dispersions to prepare two‐component waterborne polyurethanes was synthesized with terpinene‐maleic ester‐type epoxy resin (TME), polyethylene glycol (PEG), and trimethylopropane (TMP) in the presence of sulfuric acid as catalyst. The synthesis process was tracked with gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) by investigating the changes of molecular weight and glass transition temperature (Tg) of the product. FTIR was used to characterize the chemical structure of NTP. Major technical parameters of NTP were as follows: hydroxyl value 100 mg/g, hydroxyl group content 3.04%, Tg 4.03°C, and viscosity 150 mPa s (40% solid content). Effect of molecular weights and dosages of PEG on stability of NTP dispersion was examined by particle size analyses. It was found that stable dispersion was obtained when using PEG6000 as hydrophilic chain and its dosage ≥8% by the weight of TME. The average particle size of the prepared dispersion was about 200 nm from particles size and TEM analyses. The NTP dispersion showed characteristic of shear thinning, which indicated it was a pseudoplastic fluid. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of organo‐modified layered silicates on flammability performance of high‐density polyethylene/rice husk flour nanocomposite
Authors: Kord Behzad
Published: October 2010

This research was carried out to investigate on the effect of organomodified montmorillonite (OMMT) on the flame retarding characteristics and clay dispersion of composites based on high‐density polyethylene and rice husk flour. To meet this objective, the blend nanocomposites were prepared through the melt mixing of high‐density polyethylene and rice husk flour at 50% weight ratios, with various amounts of OMMT (0, 2, 4, and 6 per hundred compounds) in Hakee internal mixer; then, the samples were made by injection molding. Results indicated that the burning rate, total smoke production, and heat release rate of samples decreased with increasing the OMMT content. Also, the char residue and time to ignition increased with increasing the nanoclay loading. X‐ray diffraction patterns revealed that the nanocomposites formed were intercalated. Also, morphological findings showed that samples containing 2 per hundred compounds of OMMT had higher order of intercalation and better dispersion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Photoinduced Electron Transfer in a Distyryl BODIPY–Fullerene Dyad
Authors: Liu Jian‐Yong , El‐Khouly Mohamed E. , Fukuzumi Shunichi , Ng Dennis K. ;P.
Published: October 2010

A novel distyryl BODIPY–fullerene dyad is prepared. Upon excitation at the distyryl BODIPY moiety, the dyad undergoes photoinduced electron transfer to give a charge‐separated state with lifetimes of 476 ps and 730 ps in polar (benzonitrile) and nonpolar (toluene) solvents, respectively. Transient absorption measurements show the formation of the triplet excited state of distyryl BODIPY in the dyad, which is populated from charge‐recombination processes in both solvents.
Impact of symptom–reflux association analysis on long-term outcome after Nissen fundoplication
Authors: Broeders J A , Draaisma W A , Bredenoord A J , Smout A J , Broeders I A , Gooszen H G
Published: October 2010

Background

A positive symptom association probability (SAP) is regarded as an important selection criterion for antireflux surgery by many physicians. However, no data corroborate the relationship between symptom–reflux association and outcome, nor is it clear what impact a negative SAP has on the outcome of antireflux surgery in patients with abnormal oesophageal acid exposure. This study compared long-term outcomes of Nissen fundoplication in patients with a negative versus positive SAP.

Methods

Five-year outcome of Nissen fundoplication in patients with proton-pump inhibitor (PPI)-refractory reflux and pathological acid exposure was compared between those with (SAP+, 109) and without (SAP−, 29 patients) a positive symptom association. Symptoms, quality of life (QoL), PPI use, endoscopic findings, manometry and acid exposure were evaluated.

Results

At 5 years' follow-up, relief of reflux symptoms (95 versus 87 per cent), reduction in PPI use (80 to 25 per cent versus 85 to 14 per cent; P < 0·050) and improvement in QoL were similar in the SAP− and SAP+ groups. Reduction in acid exposure time (13·4 to 1·6 per cent versus 11·1 to 0·2 per cent of total time; P < 0·010), improvement in oesophagitis (44 to 6 per cent versus 61 to 13 per cent; P < 0·050) and increase in lower oesophageal sphincter pressure were also comparable.

Conclusion

The subjective and objective outcomes of fundoplication in patients with pathological acid exposure are comparable among those with a positive and negative SAP. Patients with pathological acid exposure and a negative SAP can also benefit from antireflux surgery.
Synthesis of Ag2O Nanocrystals with Systematic Shape Evolution from Cubic to Hexapod Structures and Their Surface Properties
Authors: Lyu Lian‐Ming , Wang Wei‐Ching , Huang Michael H.
Published: October 2010

We report the development of a facile method for the synthesis of Ag2O crystals with systematic shape evolution from cubic to edge‐ and corner‐truncated cubic, rhombicuboctahedral, edge‐ and corner‐truncated octahedral, octahedral, and hexapod structures by mixing AgNO3, NH4NO3, and NaOH at molar ratios of 1:2:11.8. A sufficient volume of NaOH solution was first added to a mixture of AgNO3 and NH4NO3 solution to promote the formation of Ag(NH3)2+ complex ions and the growth of Ag2O nanocrystals with good morphological control. The crystals are mostly submicrometer‐sized. X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy characterization has been performed to determine the crystalline surface facets. A band gap value of approximately 1.45 eV has been found for the octahedral Ag2O crystals. By changing the molar ratios of AgNO3/NH4NO3/NaOH to 1:2:41.8, corner‐depressed rhombicuboctahedra and elongated hexapods were obtained as a result of enhanced crystal growth along the [100] directions. Smaller nanocubes with average sizes of approximately 200 and 300 nm and octapods can also be prepared by adjusting the reagent molar ratios and their added volumes. Both the octahedra and hexapods with largely silver atom‐terminated {111} surface facets responded repulsively and moved to the surface of the solution when dispersing in a solution of positively charged methylene blue, but can be suspended in a negatively charged methyl orange solution. The cubes and octapods, bounded by the {100} faces, were insensitive to the molecular charges in solution. The dramatic facet‐dependent surface properties of Ag2O crystals have been demonstrated.
Neutral and Cationic Alkylmanganese(II) Complexes Containing 2,6‐Bisiminopyridine Ligands
Authors: Pérez Carmen M. , Rodríguez‐Delgado Antonio , Palma Pilar , Álvarez Eleuterio , Gutiérrez‐Puebla Enrique , Cámpora Juan
Published: October 2010

Manganese alkyl complexes stabilised by 2,6‐bis(N,N′‐2,6‐diisopropyl‐phenyl)acetaldiminopyridine (iPrBIP) have been selectively prepared by reacting suitable alkylmanganese(II) precursors, such as homoleptic dialkyls [(MnR2)n] or the corresponding THF adducts [{MnR2(thf)}2] with the mentioned ligand. For R=CH2CMe2Ph or CH2Ph, formally MnI derivatives are produced, in which one of the two R groups migrates to the 4‐position of the central pyridine ring in the iPrBIP ligand. In contrast, a true dialkyl complex [MnR2(iPrBIP)] can be isolated for R=CH2SiMe3. In solution, this compound slowly evolves to the corresponding MnI monoalkyl derivative. A detailed study of this reaction provides insights on its mechanism, showing that it proceeds through successive alkyl migrations, followed by spontaneous dehydrogenation. Protonation of [Mn(CH2SiMe3)2(iPrBIP)] with the pyridinium salt [H(Py)2][BAr′4] (Ar′=3,5‐C6H3(CF3)2) leads to the cationic species [Mn(CH2SiMe3)(Py)(iPrBIP)]+. Alternatively, the same complex can be produced by reaction of the pyridine complex [{Mn(CH2SiMe3)2(Py)}2] with the protonated ligand salt [HiPrBIP]+[BAr′4]−. This last reaction allows the synthesis of analogous cationic alkylmanganese(II) derivatives, when precursors of type [MnR2(iPrBIP)] are not available. Treatment of these neutral and cationic iPrBIP alkylmanganese derivatives with a range of typical co‐catalysts (modified methylaluminoxane (MMAO), B(C6F5)3, trimethyl or triisobutylaluminum) does not lead to active ethylene polymerisation catalysts.
Two‐Year Clinical Outcomes After Large Coronary Stent (4.0 mm) Placement: Comparison of Bare‐Metal Stent Versus Drug‐Eluting Stent
Authors: Kim Hyun‐Tae , Nam Chang‐Wook , Hur Seung‐Ho , Kim Kwon‐Bae , Lee Sang‐Hee , Hong Geu‐Ru , Park Jong‐Seon , Kim Young‐Jo , Kim Ung , Yang Tae‐Hyun , Kim Doo‐Il , Kim Dong‐Soo
Published: October 2010

Background:

The absolute benefit of drug‐eluting stents (DES) in low‐risk patients and lesions is not well established.

Hypothesis:

The long term clinical outcomes after percutaneous coronary intervention in a single coronary artery disease may not be affected by the type of stent.

Methods:

This study assessed and compared 2‐year clinical outcomes of 304 consecutive patients (147 BMS patients and 157 DES patients) treated with a single coronary stent (4.0 mm) for single de novo large coronary artery disease in 3 referral cardiac centers. The primary outcome was a composite of major adverse cardiac events at 2 years after the index procedure.

Results:

The reference vessel diameter was similar in both groups (3.92 ± 0.29 mm in BMS vs 3.95 ± 0.24 mm in DES, P = 0.50). Late loss was larger in the BMS group (1.04 ± 0.83 mm vs 0.73 ± 0.91 mm in DES, P = 0.03). The incidence of major adverse cardiac events at the 2‐year clinical follow‐up was very low, 24 of 304 patients (7.9%), regardless of stent type deployed (7.5% in BMS vs 8.3% in DES, P = 0.83). The rate of target vessel revascularization was also similar in both groups (4.8% in BMS vs 5.7% in DES, P = 0.80).

Conclusions:

Two‐year clinical outcomes after PCI with a single large coronary stent (4.0 mm) were excellent. The clinical outcomes were not affected by the type of stent used. Copyright © 2010 Wiley Periodicals, Inc.

The authors have no funding, financial relationships, or conflicts of interest to disclose.
Autonomic Dysfunction Presenting as Orthostatic Intolerance in Patients Suffering From Mitochondrial Cytopathy
Authors: Kanjwal Khalil , Karabin Beverly , Kanjwal Yousuf , Saeed Bilal , Grubb Blair P.
Published: October 2010

Background

Disturbances in autonomic nervous system function have been reported to occur in patients suffering from mitochondrial cytopathies. However, there is paucity of literature on the occurrence of orthostatic intolerance (OI) in these patients. We report on a series of patients diagnosed with mitochondrial cytopathy who developed features of autonomic dysfunction in the form of OI.

Methods

This was a single‐center report on a series of 6 patients who were followed in our clinic for orthostatic intolerance. All of these patients had a diagnosis of mitochondrial cytopathy on the basis of muscle biopsy and were being followed at a center specializing in the treatment of mitochondrial disorders. This study was approved by our local institutional review board. Each of the patients had suffered from symptoms of fatigue, palpitations, near syncope, and syncope. The diagnosis of OI was confirmed by head‐up tilt test. Collected data included demographic information, presenting symptoms, laboratory data, tilt‐table response, and treatment outcomes.

Results

Six patients (3 females) were identified for inclusion in this report. The mean age of the group was 48 ± 8 years (range, 40–60 years). All of these patients underwent head‐up tilt table testing and all had a positive response that reproduced their clinical symptoms. Among those having an abnormal tilt‐table pattern, 1 had a neurocardiogenic response, 1 had a dysautonomic response, and 4 had a postural orthostatic tachycardia response. All but 1 patient reported marked symptom relief with pharmacotherapy. The patient who failed pharmacotherapy received a dual‐chamber closed‐loop pacemaker and subsequently reported marked improvement in her symptoms with elimination of her syncope.

Conclusions

Orthostatic intolerance might be a significant feature of autonomic nervous system dysfunction in patients suffering from mitochondrial cytopathy. Copyright © 2010 Wiley Periodicals, Inc.

The authors have no funding, financial relationships, or conflicts of interest to disclose.
Intrabundle microtubule dynamics in the Arabidopsis cortical array
Authors: Shaw Sidney L. , Lucas Jessica
Published: October 2010

We tested the general hypothesis that bundling stabilizes the dynamic properties of the constituent microtubules (MTs) in vivo. We quantified the assembly dynamics of bundled and unbundled MTs in the interphase cortical array of Arabidopsis hypocotyl cells using high dynamic range spinning disk confocal microscopy. We find no evidence that bundled MTs are stabilized against depolymerization through changes to their dynamic properties. Our observations of MT plus and minus ends indicate that both bundled and unbundled polymers undergo persistent treadmilling in this system. We conclude that the temporal persistence of MT subassemblies in the Arabidopsis cortical array is largely dependent upon recruitment or nucleation of new treadmilling MTs and not on polymer stabilization. Monte Carlo simulations suggest that small differences discovered in the dynamic properties between bundled and unbundled polymers would produce relatively small macroscopic effects on the larger MT array. © 2010 Wiley‐Liss, Inc.
Midtreatment 18F‐fluorodeoxyglucose positron‐emission tomography in aggressive non‐Hodgkin lymphoma
Authors: Zinzani Pier Luigi , Gandolfi Letizia , Broccoli Alessandro , Argnani Lisa , Fanti Stefano , Pellegrini Cinzia , Stefoni Vittorio , Derenzini Enrico , Quirini Federica , Baccarani Michele
Published: October 2010

BACKGROUND:

The use of 18F‐fluorodeoxyglucose positron‐emission tomography (PET) scan has increased considerably in the clinical management of non‐Hodgkin lymphoma patients, and its role as a prognostic factor during chemotherapy has been established recently.

METHODS:

Between May 2003 and May 2009, 91 newly diagnosed patients with primary mediastinal large B‐cell lymphoma (PMLBCL) and diffuse large B‐cell lymphoma (DLBCL) were treated with 12 weekly cycles of rituximab‐MACOP‐B (n = 12 patients with PMLBCL), 6 cycles of rituximab‐CHOP21 (n = 65 patients with DLBCL, aged < 60 years and 1 patient with PMLBCL), or 8 weekly cycles of rituximab‐VNCOP‐B (n = 13 DLBCL patients, aged ≥ 60 years). All patients underwent a staging PET examination at baseline and a midtreatment (interim) PET examination after 6 weeks of rituximab‐MACOP‐B treatment, 3 cycles of rituximab‐CHOP21 treatment, or 4 weeks of rituximab‐VNCOP‐B treatment and again at the end of the chemo‐immunotherapy regimen.

RESULTS:

At midtreatment evaluation, 35 patients showed a persistently positive PET scan; only 6 (17%) of these patients achieved a continuous complete response (CCR). However, 56 patients presented with a negative interim PET, and 50 (89%) of these patients achieved and maintained a CCR. Comparison between the 2 PET groups indicated a statistically significant association between PET findings and event‐free survival (P = .0001) and overall survival (P = .0001).

CONCLUSIONS:

The results of this study indicated that midtreatment PET may represent a significant step forward in helping physicians make crucial decisions on further treatment. Cancer 2011. © 2010 American Cancer Society.
Combined modality therapy of cT2N0M0 esophageal cancer
Authors: Kountourakis Panteleimon , Correa Arlene M. , Hofstetter Wayne L. , Lee Jeffrey H. , Bhutani Manoop S. , Rice David C. , Komaki Ritsuko , Maru Dipen M. , Ross William A. , Vaporciyan Ara , Swisher Stephen G. , Ajani Jaffer A.
Published: October 2010

BACKGROUND:

Treatment strategy for patients with adequately staged cT2N0M0 carcinoma of the thoracic esophagus is currently a subject of debate. This study analyzed the largest series of consecutive cT2N0M0 esophageal cancer patients treated with preoperative chemoradiotherapy.

METHODS:

Data from all patients with cT2N0M0 (assessment included endoscopic ultrasonography and computed tomography of the chest and abdomen) thoracic esophageal cancer who were treated with preoperative chemoradiation between 1997 and 2009 were analyzed. The Cox regression model and Kaplan‐Meier plots were used to analyze the data.

RESULTS:

Data from 49 patients were analyzed. The median follow‐up was 28.46 months. Male sex and adenocarcinoma histology predominated. Pathologic complete response was observed 19 (39%) patients. The 10‐year actuarial overall survival (OS) for adenocarcinoma patients was >60%. In the univariate analysis for OS, squamous histology (P = .006), smoking (P = .015), and alcohol consumption (P = .032) were found to be associated with poor OS. In the univariate analysis for disease‐free survival (DFS), squamous histology (P = .009) and smoking (P = .014) were associated with poor DFS. In the multivariate analysis for OS, smoking was an independent prognosticator (P = .02). In the multivariate analysis for DFS, advanced pathologic stage (P = .05) and lymph node metastases (P = .006) were independent prognosticators. Patients with adenocarcinoma (P = .002) and those with pathologic N0 disease had better OS and DFS. Upward stage migration occurred in only 10% of patients.

CONCLUSIONS:

These data suggest that smoking and alcohol influence the long‐term outcome of patients with cT2N0M0 disease. Adenocarcinoma patients treated with trimodality therapy had an excellent actuarial 10‐year OS and a high rate of pathologic complete response. Trimodality therapy should be prospectively compared with primary surgery in these patients. Cancer 2011. © 2010 American Cancer Society.
A Phase 2 study of combination therapy with arsenic trioxide and gemtuzumab ozogamicin in patients with myelodysplastic syndromes or secondary acute myeloid leukemia
Authors: Sekeres Mikkael A. , Maciejewski Jaroslaw P. , Erba Harry P. , Afable Manuel , Englehaupt Ricki , Sobecks Ronald , Advani Anjali , Seel Sherry , Chan Josephine , Kalaycio Matt E.
Published: October 2010

BACKGROUND:

Higher‐risk myelodysplastic syndromes (MDS) are similar pathobiologically to acute myeloid leukemia (AML), particularly in older adults. AML therapies thus may have activity in MDS. In the current study, phase 2 study data of arsenic trioxide (ATO) and gemtuzumab ozogamicin (GO) in CD33‐positive patients with MDS and secondary AML (sAML) were presented.

METHODS:

Between June 2004 and February 2006, 30 patients with higher‐risk MDS or sAML received ATO (at a dose of 0.25 mg/kg intravenously for 5 days during Week 1, then twice weekly during Weeks 2‐12) and GO (at a dose of 3 mg/m2 on Day 8) for 1 or 2 cycles of 12 weeks each. The primary endpoint was response as per MDS or AML International Working Group (IWG) criteria. Adverse events were collected throughout treatment. Patients were followed for a minimum of 3 years for survival.

RESULTS:

The median patient age was 69 years. A total of 18 patients had MDS, 12 had sAML, and 19 had been previously treated. Seventeen patients (57%) completed ≥1 cycle, and 7 patients (23%) completed 2 cycles. IWG responses occurred in 9 patients (30%) according to IWG MDS criteria (including 2 of 7 patients who failed hypomethylating agents) and 3 of 12 AML patients (25%) according to IWG AML criteria. Grade 3/4 (according to National Cancer Institute Common Toxicity Criteria [version 3.0]) thrombocytopenia occurred in 47% of patients, neutropenia in 63%, and anemia in 37% of patients. The median overall survival was 9.7 months (28.6 months in responders and 7.6 months in nonresponders; P <.001). Patients who completed 2 cycles of therapy spent a median of 13 days in the hospital.

CONCLUSIONS:

Combination therapy with ATO and GO was found to have acceptable response rates and toxicity, and may be a viable treatment option to standard induction therapy, particularly for patients who fail therapy with hypomethylating agents. Cancer 2011. © 2010 American Cancer Society.
Subcellular distribution of connexin45 in OFF bipolar cells of the mouse retina
Authors: Hilgen Gerrit , von Maltzahn Julia , Willecke Klaus , Weiler Reto , Dedek Karin
Published: October 2010

In the mouse retina, connexin45 (Cx45) participates in the gap junction between ON cone bipolar cells and AII amacrine cells, which constitutes an essential element of the primary rod pathway. Although it has been shown that Cx45 is also expressed in OFF bipolar cells, its subcellular localization and functional role in these cells are unknown. Here, we analyzed the localization of Cx45 on OFF bipolar cells in the mouse retina. For this, we used wild‐type mice and a transgenic mouse line that expressed, in addition to native Cx45, a fusion protein consisting of Cx45 and the enhanced green fluorescent protein (EGFP). Cx45‐EGFP expression generates an EGFP signal at gap junctions containing Cx45. Combining immunohistochemistry with intracellular injections, we found that Cx45 was present on dendrites and axon terminals of all OFF bipolar cell types. Cx45 was not found at intersections of two terminal processes of the same type, suggesting that Cx45 might not form gap junctions between axon terminals of the same OFF bipolar cell type but rather might connect OFF bipolar cells to amacrine or ganglion cells. In OFF bipolar cell dendrites, Cx45 was found predominantly in the proximal outer plexiform layer (OPL), well below the cone pedicles. Cx45 did not colocalize with Cx36, which is found predominantly in the distal OPL. We conclude that Cx45 is expressed on OFF bipolar cell dendrites, presumably forming gap junctions with cells of the same type, and on OFF bipolar cell axon terminals, presumably forming heterologous gap junctions with other retinal neurons. J. Comp. Neurol. 519:433–450, 2011. © 2010 Wiley‐Liss, Inc.
Uptake of Formic Acid on Thin Ice Films and on Ice Doped with Nitric Acid between 195 and 211 K
Authors: Romanias Manolis N. , Zogka Antonia G. , Stefanopoulos Vassileios G. , Papadimitriou Vassileios C. , Papagiannakopoulos Panos
Published: October 2010

The adsorption of formic acid on thin ice films and on ice doped with nitric acid (1.96, 7.69 and 53.8 wt %) is studied as a function of temperature T=195–211 K and gas concentration (0.33–10.6)×1011 molecule cm−3. Experiments are performed in a Knudsen flow reactor coupled with a quadrupole mass spectrometer. The initial uptake coefficients γ are strongly and inversely dependent on the ice temperature. Initial uptake is determined at low surface coverages and ranges from (0.65–3.78)×10−3. The adsorption uptake of formic acid on pure ice films and on ice lightly doped with HNO3 is a reversible process, and the adsorption isotherms exhibit Langmuir behaviour. Nmax(1) is (2.94±0.67)×1014 molecule cm−2, in good agreement with previous measurements. The temperature dependence of KLin is very well represented by the expression: KLin(1)=(1.43±0.32)×10−8 exp[(4720±520)/T] cm3 molecule−1; the quoted uncertainty is at the 95 % level of confidence and includes systematic uncertainties. Formic acid uptakes on ice films highly doped with HNO3 (53.8 wt %) are two orders of magnitude higher than those measured on pure ice films and irreversible, thus indicating the formation of a supercooled liquid layer on the ice films upon which dissolution of formic acid occurs. Finally, the atmospheric lifetime of formic acid due to heterogeneous loss on cirrus cloud ice particles and the removal of formic acid by adsorption are estimated under conditions related to the upper troposphere.
Overview
Authors: Kuffler S. W.
Published: October 2010

The sections in this article are:

Chemical Specialization of Neurons

The Neuronal Membrane

“Trophic” Interaction

Memory and Learning

Cellular Basis of Higher Functions

Genetic Dissection of the Nervous System

Prospects
Impact of endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) in lymph nodal and mediastinal lesions: A multicenter experience
Authors: Zeppa Pio , Barra Enrica , Napolitano Vincenzo , Cozzolino Immacolata , Troncone Giancarlo , Picardi Marco , De Renzo Amalia , Mainenti Pier Paolo , Vetrani Antonio , Palombini Lucio
Published: October 2010

Endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) is an established procedure in lung cancer (LC) staging and in the diagnosis of mediastinal masses. Most of the experiences reported refer to single specialized centers where dedicated teams of endoscopists and pathologists perform the procedure. We report the EUS‐FNA experience of a cooperation group involving clinicians and cytopathologists from three hospitals. Fifty‐seven consecutive EUS‐FNA of mediastinal nodes in LC patients, eight mediastinal and two subdiaphragmatic masses were collected in 3 years. EUS‐FNA was performed by two endoscopists and three experienced pathologists. On‐site evaluation was performed in all cases by the three cytopathologists. Lymph node negative cases underwent surgery, which confirmed the cytological diagnoses but also detected two false negatives. Four of the 10 EUS cytological diagnoses of mediastinal and subdiaphragmatic masses were histologically confirmed. All EUS diagnoses were blindly reviewed by three pathologists to assess intra and interpersonal reproducibility. FNA‐EUS diagnoses were: 10 inadequate (17%), 10 negative (17%), 4 suspicious (7%) and 33 positive (59%). Diagnoses of mediastinal and subdiaphragmatic masses were: relapse of lung carcinoma (3), mesenchimal tumor not otherwise specifiable (3), gastrointestinal stromal tumor (GIST) (1), esophageal carcinoma (2) and paraganglioma (1). The sensitivity attained was 85% and the specificity 100%; revision of the slides demonstrated a significant diagnostic reproducibility of the three cytopathologists (P < 0.5). The sensitivity and specificity attained were similar to those reported in the literature suggesting that experienced cytopathologists and endoscopists from different institutions can employ the same procedure reaching comparable results. Diagn. Cytopathol. 2010. © 2010 Wiley‐Liss, Inc.
Lack of motor neuron differentiation is an intrinsic property of the mouse secondary neural tube
Authors: Shum Alisa S.W. , Tang Louisa S.C. , Copp Andrew J. , Roelink Henk
Published: October 2010

The cranial part of the amniote neural tube is formed by folding and fusion of the ectoderm‐derived neural plate (primary neurulation). After posterior neuropore closure, however, the caudal neural tube is formed by cavitation of tail bud mesenchyme (secondary neurulation). In mouse embryos, the secondary neural tube expresses several genes important in early patterning and induction, in restricted domains similar to the primary neural tube, yet it does not undergo neuronal differentiation, but subsequently degenerates. Although the secondary neural tube, isolated from surrounding tissues, is responsive to exogenous Sonic Hedgehog proteins in vitro, motor neuron differentiation is never observed. This cannot be attributed to the properties of the secondary notochord, since it is able to induce motor neuron differentiation in naive chick neural plate explants. Taken together, these results support that the lack of motor neuron differentiation is an intrinsic property of the mouse secondary neural tube. Developmental Dynamics 239:3192–3203, 2010. © 2010 Wiley‐Liss, Inc.