bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell surface display of carbonic anhydrase on Escherichia coli using ice nucleation protein for CO2 sequestration
Authors: Fan Li‐Hai , Liu Ning , Yu Ming‐Rui , Yang Shang‐Tian , Chen Huan‐Lin 
Published: July 2011

AbstractCarbonic anhydrase (CA) has recently gained renewed interests for its potential as a mass‐transfer facilitator for CO2 sequestration. However, the low stability and high price severely limit its applications. In this work, the expression of α‐CA from Helicobacter pylori on the outer membrane of Escherichia coli using a surface‐anchoring system derived from ice nucleation protein (INP) from Pseudomonas syringae was developed. To find the best surface anchoring motif, full‐length INP (114 kDa), truncated INP (INP‐NC, 33 kDa), and INP's N‐domain with first two subunits (INP‐N, 22 kDa) were evaluated. Two vectors, pKK223‐3 and pET22b(+), with different promoters (T7 and Tac) were used to construct the fusion genes, and for each vector, three recombinant strains, each expressing a different length of the fusion protein, were obtained. SDS–PAGE, Western blot, immunofluorescence microscopy, FACS, and whole‐cell ELISA confirmed the expression of fusion proteins on the surface of E. coli. The smallest fusion protein with INP‐N as the anchoring motif had the highest expression level and CA activity, suggesting that INP‐N is the best carrying protein due to its smaller size. Also, the T7 promoter in pET22b(+) induced with 0.2 mM IPTG gave high protein expression levels, whereas the Tac promoter in pKK223‐3 gave low expression levels. The surface displayed CA was at least twofold more stable than that of the free form, and did not show any adverse effect on cell growth and outer membrane integrity. Cells with surface displayed CA were successfully used to facilitate CO2 sequestration in contained liquid membrane (CLM). Biotechnol. Bioeng. 2011;108: 2853–2864. © 2011 Wiley Periodicals, Inc.
A new fluorescence complementation biosensor for detection of estrogenic compounds
Authors: McLachlan Michael J. , Katzenellenbogen John A. , Zhao Huimin 
Published: July 2011

AbstractEstrogenic compounds are an important class of hormonal substances that can be found as environmental contaminants, with sources including pharmaceuticals, human and animal waste, the chemical industry, and microbial metabolism. Here we report the creation of a biosensor useful for monitoring such compounds, based on complementation of fluorescent protein fragments. A series of sensors were made consisting of fragments of a split mVenus fluorescent protein fused at several different N‐terminal and C‐terminal positions flanking the ligand binding domain of the estrogen receptor alpha. When expressed in HeLa cells, sensor 6 (ERα 312‐595) showed a nine‐fold increase in fluorescence in the presence of estrogen receptor agonists or antagonists. Sensor 2 (ERα 281‐549) discriminated between agonists and antagonists by showing a decrease in fluorescence in the presence of agonists while being induced by antagonists. The fluorescent signal of sensor 6 increased over a period of 24 h, with a two‐fold induction visible at 4 h and four‐fold at 8 h of ligand incubation. Ligand titration showed a good correlation with the known relative binding affinities of the compound. The sensor could detect a number of compounds of interest that can act as environmental endocrine disruptors. The lack of a substrate requirement, the speed of signal development, the potential for high throughput assays, and the ability to distinguish agonists from antagonists make this an attractive sensor for widespread use. Biotechnol. Bioeng. 2011;108: 2794–2803. © 2011 Wiley Periodicals, Inc.
Design and Synthesis of Iridium Bis(carbene) Complexes for Efficient Blue Electrophosphorescence
Authors: Hsieh Cheng‐Han , Wu Fang‐Iy , Fan Chun‐Hsiang , Huang Min‐Jie , Lu Kun‐Yi , Chou Pei‐Yu , Yang Yu‐Han Ou , Wu Shih‐Hsiang , Chen I‐Chia , Chou Shu‐Hua , Wong Ken‐Tsung , Cheng Chien‐Hong 
Published: July 2011

AbstractFive iridium bis(carbene) complexes, [Ir(pmi)2(pypz)] (1), [Ir(mpmi)2(pypz)] (2), [Ir(fpmi)2(pypz)] (3), [Ir(fpmi)2(pyim)] (4), and [Ir(fpmi)2(tfpypz)] (5) (pmi=1‐phenyl‐3‐methylimdazolin‐2‐ylidene‐C,C2′; fpmi=1‐(4‐fluorophenyl)‐3‐methylimdazolin‐2‐ylidene‐C,C2′; mpmi=1‐(4‐methyl‐phenyl)‐3‐methylimdazolin‐2‐ylidene‐C,C2′; pypz=2‐(1H‐pyrazol‐5‐yl)pyridinato; pyim=2‐(1H‐imidazol‐2‐yl)pyridinato; and tfpypz=2‐(3‐(trifluoromethyl)‐1H‐pyrazol‐5‐yl)pyridinato), were synthesized and their structures were characterized by NMR spectroscopy, mass spectroscopy and X‐ray diffraction. These complexes showed phosphorescent emission with the emission maxima between 453 and 490 nm. Various spectrophotometric measurements, cyclic voltammetric studies, and density functional theory (DFT) calculations show that, unlike most of the phosphorescent cyclometalated iridium complexes, the lowest unoccupied molecular orbital (LUMO) energy and the emissive state of these iridium complexes are mainly controlled by the N,N′‐heteroaromatic (N^N) ligand. Despite the fact that the LUMO levels of these complexes are mainly on the N^N ligands, the efficiencies of the electroluminescent (EL) devices are very high. For example, the EL devices using [Ir(mpmi)2(pypz)], [Ir(fpmi)2(pypz)], and [Ir(fpmi)2(tfpypz)] as the dopant emitters exhibited light‐ to deep‐blue electrophosphorescence with external quantum efficiencies of 15.2, 14.1, and 7.6 % and Commission Internationale d’Énclairage (x,y) coordinates (CIEx,y) of (0.14, 0.27), (0.14, 0.18) and (0.14, 0.10), respectively.
Theoretical and X‐ray Crystallographic Evidence of a Fluorine‐Imine Gauche Effect: An Addendum to Dunathan’s Stereoelectronic Hypothesis
Authors: Sparr Christof , Salamanova Evdokiya , Schweizer W. Bernd , Senn Hans Martin , Gilmour Ryan 
Published: July 2011

AbstractThe preference of β‐fluoroimines to adopt a gauche conformation has been studied by single‐crystal X‐ray diffraction analysis and DFT methods. Empirical and theoretical evidence for a preferential gauche arrangement around the NCCF torsion angle (ϕ) is presented ((E)‐2‐fluoro‐N‐(4‐nitrobenzylidene)ethanamine: ϕNCCF=70.0°). In the context of this study, the analysis of a pyridoxal‐derived β‐fluoroaldimine was performed, a species that is implicated in the inhibition of pyridoxal phosphate (PLP)‐dependent enzymes by β‐fluoroamine derivatives. The gauche preference of the internal aldimine (=NCH2CH2F) that can be rationalized by stereoelectronic arguments does not hold for the corresponding external system (NCHCH2F) (Emin when ϕNCCF=120°). Moreover, the CF bond is lengthened by more than 0.02 Å at ϕNCCF=±90°, when it is exactly antiperiplanar to the conjugated imine. This activation of the CF σ bond by an adjacent π system constitutes an addendum to Dunathan’s stereoelectronic hypothesis.
Tissue Uptake Study and Photodynamic Therapy of Melanoma‐Bearing Mice with a Nontoxic, Effective Chlorin
Authors: Dąbrowski Janusz M. , Krzykawska Martyna , Arnaut Luis G. , Pereira Mariette M. , Monteiro Carlos J. P. , Simões Sérgio , Urbańska Krystyna , Stochel Grażyna 
Published: July 2011

AbstractChlorins have intense red absorptions and high tumor affinities that make them interesting candidates for photodynamic therapy (PDT) of cancer. This paper reports cytotoxicity, phototoxicity, in vitro cellular uptake, and in vivo biodistribution and PDT efficacy of a synthetic chlorin derivative (TCPCSO3H) towards Cloudman melanoma cells (S91). No cytotoxic effects were observed in vitro at concentrations up to 20 μm, and no toxicity was observed in vivo in DBA mice with doses up to 2 mg kg−1. Pharmacokinetics and biodistribution of TCPCSO3H were evaluated in vivo in DBA mice bearing S91 tumors. TCPCSO3H demonstrated preferential accumulation in S91 mouse melanoma, with tumor‐to‐normal tissue ratios of 5 and 11 for muscle and skin, respectively, 24 h after intravenous injection of 2 mg kg−1. Photodynamic therapy performed under these conditions with 70 mW cm−2 diode laser irradiation at 655 nm for 25 min (total light dose=105 J cm−2) resulted in scab formation, followed by temporary or permanent (>60 days) tumor remission. According to the Kaplan–Meier analysis, the median survival time of the control group was 9 days, whereas that of the treated group was 38 days.
Ultrafast Electron Transfer from Photoexcited CdSe Quantum Dots to Methylviologen
Authors: Scholz Frank , Dworak Lars , Matylitsky Victor V. , Wachtveitl Josef 
Published: July 2011

AbstractThe ultrafast charge separation at the quantum dot (QD)/molecular acceptor interface was investigated in terms of acceptor concentration and the size of the QD. Time‐resolved experiments revealed that the electron transfer (ET) from the photoexcited QD to the molecular acceptor methylviologen (MV2+) occurs on the fs time scale for large acceptor concentrations and that the ET rate is strongly reduced for low concentrations. The increase in the acceptor concentration is accompanied with a growth in the overlap of donor and acceptor wavefunctions, resulting in a faster reaction until the MV2+ concentration reaches a saturation limit of 0.3–0.4 MV2+ nm−2. Moreover, we found significant QD size dependence of the ET reaction, which is explained by a change of the free energy (ΔG).
Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review
Authors: Tessonnier Jean‐Philippe , Su Dang Sheng 
Published: July 2011

AbstractTremendous progress has been achieved during the past 20 years on not only improving the yields of carbon nanotubes and move progressively towards their mass production, but also on gaining a profound fundamental understanding of the nucleation and the growth processes. Parameters that influence the yield but also the quality (e.g., microstructure, homogeneity within a batch) are better understood. The influence of the carbon precursor, the reaction conditions, the presence of a catalyst, the chemical and physical status of the latter, and other factors have been extensively studied. The purpose of the present Review is not to list all the experiments reported in the literature, but rather to identify trends and provide a comprehensive summary on the role of selected parameters. The role of the catalyst occupies a central place in this Review as a careful control of the metal particle size, particle dispersion on the support, the metastable phase formed under reaction conditions, its possible reconstruction, and faceting strongly influence the diameter of the carbon nanotubes, their structure (number of walls, graphene sheet orientation, chirality), their alignment, and the yield. The identified trends will be compared with recent observations on the growth of graphene. Recent results on metal‐free catalysts will be analyzed from a different perspective.
Voltammetric Determination of Hemoglobin Using a Pencil Lead Electrode
Authors: Majidi Mir Reza , Saadatirad Afsaneh , Alipour Esmaeel 
Published: July 2011

AbstractIn this paper the electrochemical behavior of hemoglobin (Hb) immobilized on a pencil lead electrode (PLE) was investigated. Immobilization of Hb on the pencil lead electrode was performed by nonelectrochemical and electrochemical methods. In phosphate buffer solution with pH 7.0 Hb showed a pair of well‐defined and nearly reversible redox waves (the anodic and cathodic peak potentials are located at −0.18 V and −0.22 V, respectively). The dependence of the anodic peak potential (Epa) on the pH of the buffer solution indicated that the conversion of HbFe(III)/HbFe(II) is a one‐electron‐transfer reaction process coupled with one‐proton‐transfer. In addition the effect of scan rate on peak currents and peak separation potential was investigated and electrochemical parameters such as α and ks were calculated. In the second part of this work, the ability of the electrode for determination of Hb concentration was investigated. The results showed a linear dynamic range from 0.15 to 2 µM and a detection limit of 0.11 µM. The relative standard deviation is 4.1 % for 4 successive determinations of a 1 µM Hb solution.
Amperometric Ethanol Biosensors Based on Chitosan‐NAD+‐Alcohol Dehydrogenase Films
Authors: Zhang Maogen , Gorski Waldemar 
Published: July 2011

AbstractThe reagentless and oxygen‐independent biosensors for ethanol were developed based on the covalent immobilization of alcohol dehydrogenase (ADH) and its cofactor nicotinamide adenine dinucleotide (NAD+) on chitosan (CHIT) chains. The CHIT‐NAD+‐ADH structures were adsorbed onto carbon nanotubes (CNT) in order to provide a signal transduction based on the recycling of redox states of NAD cofactor at CNT (detection limit, 8–30 µM ethanol; dynamic range up to 20 mM). The CHIT‐NAD+‐dehydrogenase/CNT hybrid material represents a general approach to the development of dehydrogenases‐based electrochemical biosensors. Interestingly, the CHIT‐NAD+ solutions preserved their enzymatic activity even after five years of storage at 4 °C.
An individual-based modeling approach for evaluation of endpoint sensitivity in harpacticoid copepod life-cycle tests and optimization of test design
Authors: Preuss Thomas G , Brinkmann Markus , Lundström Elin , Bengtsson Bengt-Erik , Breitholtz Magnus 
Published: July 2011

Abstract
In the present study, an individual-based model for Nitocra spinipes was developed and used to optimize the test design of a proposed Organisation for Economic Co-operation and Development test guideline for harpacticoid copepods. The variability between individuals was taken into account, based on measured data, leading to stochastic model output. Virtual experiments were performed with the model to analyze the endpoint sensitivity and the effect of number of replicates and inspection intervals on statistical power. The impact of mortality was evaluated; most sublethal effects could not be determined if the mortality was ≥70%. Most sensitive to mortality was the determination of effects on brood size, for which the statistical power was reduced at 10% mortality. Our simulations show that increasing the number of replicates from 72 to 96 or 144 has little impact on the statistical power, whereas 25 replicates disallow relevant endpoint detection. Furthermore, it was demonstrated that the proposed 1D inspection interval can be shifted to a 3D interval, without losing statistical power. It was demonstrated that developmental endpoints have a higher statistical power than reproductive endpoints in the current test design. The present study highlights the usefulness of individual-based models for optimizing the experimental design. The use of such models in the development of standard test guidelines will lead to a faster and less resource-demanding process. Environ. Toxicol. Chem. 2011;30:2353–2362. © 2011 SETAC
Has the introduction of S&P 500 ETF options led to improvements in price discovery of SPDRs?
Authors: Chen Wei‐Peng , Chung Huimin 
Published: July 2011

AbstractThis study sets out to investigate trading in Standard and Poor's Depository Receipt Trust Series I (SPDR) options and the impact on the price‐discovery process of SPDRs. The empirical results reveal a significant rise in liquidity within the SPDR market following the introduction of SPDR options. Furthermore, the results also show that the introduction of SPDR options has led to a significant improvement in the information share of SPDRs, and that the contribution of SPDRs to price discovery has become very close to that of E‐mini index futures. These findings imply that developments in the derivatives market can lead to improvements in market quality, including the level of liquidity and price discovery of the underlying securities. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark 32:683–711, 2012
Biomarkers in dementia with Lewy bodies: a review
Authors: Sinha Namrta , Firbank Michael , O'Brien John T. 
Published: July 2011

BackgroundDementia with Lewy bodies (DLB) shares common clinical, neuropsychological and pathological features with other dementia subtypes, such as Alzheimer's disease (AD), making it difficult to differentiate in clinical practice. Despite the development of consensus diagnostic criteria, many cases are missed, and biomarkers to assist with diagnosis would represent important advances. Our aim was to review the literature to identify potential biomarkers that may distinguish DLB from other dementia subtypes, especially AD.MethodThe literature search was performed using Medline up to October 2010 for imaging studies [single‐photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI) and amyloid imaging] and cerebrospinal fluid (CSF) markers in DLB. Individual articles were examined for additional references. The abstracts of the identified articles were read to determine the most relevant papers, which became the basis for this review.ResultsThe most robust evidence available was for striatal dopamine transporter activity visualised by 123I‐labelled N‐(3‐fluoropropyl)‐2β‐carbomethoxy‐3β‐(4‐iodophenyl)nortropane (123I‐FP‐CIT) SPECT. Several other imaging techniques have also reported promising results, such as [18F]fluorodopa PET, which assesses nigrostriatal integrity; [18F]fluorodeoxyglucose PET, which assesses metabolic deficits; and meta‐iodobenzylguanidine imaging, which assesses sympathetic cardiac denervation. Data from studies using CSF measures of amyloid and tau, occipital hypoperfusion on SPECT and preservation of medial temporal lobe structures on MRI suggest that they may offer less diagnostic discrimination.ConclusionSeveral potential biomarkers have shown good diagnostic accuracy for DLB, but apart from FP‐CIT SPECT, there is now a need for larger clinical multi‐site studies, as well as for studies with pathological verification of diagnosis, before their use could be recommended for routine clinical practice. Copyright © 2011 John Wiley & Sons, Ltd.
Generation of pyrrolo[2,1‐a]isoquinoline derivatives from N‐ylides: Synthetic control and structural characterization
Authors: Dumitrascu Florea , Caira Mino R. , Georgescu Emilian , Georgescu Florentina , Draghici Constantin , Popa Marcel Mirel 
Published: July 2011

AbstractNew pyrrolo[2,1‐a]isoquinolines were obtained by two one‐pot procedures via 1,3‐dipolar cycloaddition between the isoquinolinium N‐ylides and symmetrical acetylenic dipolarophiles, avoiding the formation of dihydro intermediates. For structural comparison, the dihydro derivatives obtained by a classical two‐stage reaction were characterized by NMR and X‐ray crystallography, allowing complete stereochemistry assignments. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:723–729, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/.20740
The hydrological behaviour of urban streets: long‐term observations and modelling of runoff losses and rainfall–runoff transformation
Authors: Ramier D. , Berthier E. , Andrieu H. 
Published: July 2011

AbstractRunoff on impervious surfaces (roads, roofs, etc.) raises a number of environmental and road safety‐related problems. The primary objective of this research effort is to improve our knowledge of the hydrological behaviour of impervious urban surfaces in order to better assess runoff on these surfaces and its subsequent consequences. This article will focus on two street stretches studied over a 38‐month period. Measurements of rainfall and runoff discharge on these stretches have made it possible to estimate runoff losses as well as to constitute a database for modelling purposes. On the basis of these data, two models have been used, one simple the other more detailed and physically based. For both models, runoff discharges at a 3‐min time step are well reproduced, although runoff coefficients and runoff losses are still poorly estimated. Detailed analyses of experimental data and model output, however, indicate that runoff losses could be quite high on such ‘impervious surfaces’ (between 30 and 40% of total rainfall, depending on the street stretch) and that these losses are mainly because of evaporation and infiltration inside the road structure. Copyright © 2011 John Wiley & Sons, Ltd.
Breast cancer incidence trends in Norway—explained by hormone therapy or mammographic screening?
Authors: Hofvind Solveig , Sakshaug Solveig , Ursin Giske , Graff‐Iversen Sidsel 
Published: July 2011

AbstractA decline in breast cancer incidence has been observed in several countries after 2002. Reduced use of menopausal hormonal therapy (HT), as a consequence of the publication of results from the Women's Health Initiative, has been argued to be the main reason. In Norway, the governmentally funded Norwegian Breast Cancer Screening Program (NBCSP) was implemented during the same time period as the increased use of HT. This study investigated trends in breast cancer incidence by use of HT and introduction of the screening program. We obtained rates of breast cancer from the Cancer Registry of Norway and sales data of HT preparations from the Norwegian Institute of Public Health. Mammography rates were estimated from published reports. Breast cancer incidence rates increased steadily from 1956 to the end of the 20th century, particularly in women aged 55–69 during 1996–2002 residing in the counties where the NBCSP was first introduced. The rates declined after 2002–2003. HT use increased in 1987–2001, peaking around year 2000. In particular, sales of combined estrogen and progestogen preparations declined after 2002. Among women aged 55–59, rates of hormone receptor positive breast cancers peaked in 2000–2003. No such trend was seen in other age groups. In conclusion, the interpretation of breast cancer incidence trends in Norway from 1987 to 2009 is complicated because the NBCSP was introduced during a period with increasing HT use. Both factors likely contributed to the observed trends, and the role of each may vary across age groups.
On the simultaneity problem in the aid and growth debate
Authors: Brückner Markus 
Published: July 2011

SUMMARYThis paper shows that foreign aid has a significant positive average effect on real per capita gross domestic product (GDP) growth if, and only if, the quantitatively large negative reverse causal effect of per capita GDP growth on foreign aid is adjusted for in the growth regression. Instrumental variables estimates show that a 1 percentage point increase in GDP per capita growth decreased foreign aid by over 4%. Adjusting for this quantitatively large, negative reverse causal effect of economic growth on foreign aid shows that a 1% increase in foreign aid increased real per capita GDP growth by around 0.1 percentage points. Copyright © 2011 John Wiley & Sons, Ltd.
Caffeine induction of sulfotransferases in rat liver and intestine
Authors: Zhou Tianyan , Chen Yue , Huang Chaoqun , Chen Guangping 
Published: July 2011

ABSTRACTSulfotransferases (SULTs) are important phase II drug‐metabolizing enzymes. Regulation of SULTs by hormones and other endogenous molecules is relatively well understood, while xenobiotic induction of SULTs is not well studied. Caffeine is one of the most widely consumed psychoactive substances. However, SULT regulation by caffeine has not been reported. In this report, male and female rats were treated with different oral doses of caffeine (2, 10, 50 mg kg−1 per day) for 7 days. Western blot and real‐time RT‐PCR were used to investigate the changes in SULT protein and mRNA expression following the caffeine treatment. Caffeine induced both rat aryl sulfotransferase (rSULT1A1, AST‐IV) and rat hydroxysteroid sulfotransferase (rSULT2A1, STa) in the liver and intestine of female rats in a dose‐dependent manner. Caffeine induction of rSULT1A1 and rSULT2A1 in the female rat intestine was much stronger than that in the liver. Although caffeine induced rSULT1A1 significantly in the male rat liver, it did not significantly induce rSULT2A1. In male rat intestine, caffeine significantly induced rSULT2A1. The different SULTs induction patterns in male and female rats suggest that the regulation of rat SULTs by caffeine may be affected by different hormone secretion patterns and levels. Our results suggest that consumption of caffeine can induce drug metabolizing SULTs in drug detoxification tissues. Copyright © 2011 John Wiley & Sons, Ltd.