bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporating fertility preservation into the care of young oncology patients
Authors: Redig Amanda J. , Brannigan Robert , Stryker Steven J. , Woodruff Teresa K. , Jeruss Jacqueline S.
Published: August 2010

As the number of cancer survivors continues to increase, oncologists are faced with the challenge of providing cancer therapy to patients who may 1 day want to have children. Yet, gonadotoxic cancer treatments can compromise future fertility, either temporarily or permanently. There are established means of preserving fertility before cancer treatment; specifically, sperm cryopreservation for men and in vitro fertilization and embryo cryopreservation for women. Several innovative techniques are being actively investigated, including oocyte and ovarian follicle cryopreservation, ovarian tissue transplantation, and in vitro follicle maturation, which may expand the number of fertility preservation choices for young cancer patients. Fertility preservation may also require some modification of cancer therapy; thus, patients' wishes regarding future fertility and available fertility preservation alternatives should be discussed before initiation of therapy. This commentary provides an overview of the range of fertility preservation options currently available and under development, using case‐based discussions to illustrate ways in which fertility preservation can be incorporated into oncology care. Cases involving breast cancer, testicular cancer, and rectal cancer are described to illustrate fertility issues experienced by male and female patients, as well as to provide examples of strategies for modifying surgical, medical, and radiation therapy to spare fertility. Current guidelines in oncology and reproductive medicine are also reviewed to underscore the importance of communicating fertility preservation options to young patients with cancer. Cancer 2011. © 2010 American Cancer Society.
Clinical impact of amphiregulin expression in patients with epidermal growth factor receptor (EGFR) wild‐type nonsmall cell lung cancer treated with EGFR‐tyrosine kinase inhibitors
Authors: Chang Myung Hee , Ahn Hee Kyung , Lee Jeeyun , Jung Chan‐Kwon , Choi Yoon‐La , Park Yeon Hee , Ahn Jin Seok , Park Keunchil , Ahn Myung‐Ju
Published: August 2010

BACKGROUND:

In patients with nonsmall cell lung cancer (NSCLC), several studies have demonstrated a positive correlation between somatic mutation in the epidermal growth factor receptor (EGFR) tyrosine kinase domain and clinical outcomes with the use of EGFR tyrosine kinase inhibitors (TKIs). However, some patients with wild‐type (WT) EGFR also responded to EGFR TKIs and remained stable. Recently, amphiregulin (AR) has been suggested as a predictive marker for EGFR TKIs in patients with WT EGFR‐positive NSCLC. The objective of the current study was to evaluate the association between AR expression and the efficacy of using EGFR TKIs in the treatment of patients with WT EGFR‐positive NSCLC.

METHODS:

Seventy‐three patients with WT EGFR‐positive NSCLC received treatment with gefitinib or erlotinib between May 2005 and December 2008. AR expression was assessed by immunohistochemistry.

RESULTS:

The clinical response to EGFR TKIs was reassessed for all patients as follows: 16 of 73 patients had a partial response (21.9%), 12 patients had stable disease (16.5%), and 45 patients had progressive disease (61.6%). AR expression was positive in 24 of 40 patients (60%). The ability to achieve disease control did not differ significantly between AR‐positive patients and AR‐negative patients (P = .188). At a median follow‐up of 25.4 months (range, 10.5‐53.3 months), progression‐free survival was 8.1 weeks in AR‐positive patients and 4 weeks in AR‐negative patients (P = .025), and overall survival was significantly longer in AR‐positive patients than in AR‐negative patients (12.2 months vs 4.1 months; P = .001).

CONCLUSIONS:

The current results suggested that patients with WT EGFR‐positive NSCLC who have AR‐positive tumors may benefit clinically from treatment with EGFR TKIs, indicating that AR expression may be a potential marker for the selection of EGFR‐TKI treatment for patients with WT EGFR‐positive NSCLC. Cancer 2011. © 2010 American Cancer Society.
Cytologic diagnosis and differential diagnosis of lung carcinoid tumors a retrospective study of 63 cases with histologic correlation
Authors: Stoll Lisa Marie , Johnson Michael W. , Burroughs Frances , Li Qing Kay
Published: August 2010

BACKGROUND:

Neuroendocrine (NE) neoplasms of the lung are a spectrum of tumors including typical carcinoid (TC), atypical carcinoid tumor (ACT), small cell lung carcinoma (SCLC), and large cell NE carcinoma (LCNEC). Given the overlapping features within these tumors, misclassification is a known risk, with significant treatment consequences.

METHODS:

A search of the pathology archives from The Johns Hopkins Hospital yielded 390 cases of TC diagnosed over 20 years. Sixty‐three cytology cases with corresponding surgical material were identified. The cytology specimens were comprised of 49 cases of lung fine‐needle aspiriation specimens and 14 cases of lung brushings/washings.

RESULTS:

Among 63 paired cases, 32 cases (51%) demonstrated concordant and 31 cases (49%) demonstrated discordant diagnoses. Among discordant cases, the most notable findings included overdiagnosis of TC as SCLC (4 cases; 6%), ACT (4 cases; 6%), and poorly differentiated carcinoma with NE features (5 cases; 8%) as well as misdiagnosis of other lesions as TC (4 cases; 6%) on cytology.

CONCLUSIONS:

The significant morphologic factors for distinguishing low‐grade TC from ACT, SCLC, or carcinoma remain the critical evaluation of nuclear features, chromatin patterns, and assessment of nucleoli. Nuclear molding and crowding are not discernible features because they may be found on smears with increased cellularity. Crush artifact can occur in both low‐grade and high‐grade NE neoplasms and may cause a misinterpretation of SCLC. Other artifacts resulting from delayed fixation or poor processing and sampling error are potential causes of incorrect interpretations. Ki‐67 staining may be useful in difficult cases. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.
Effects of natural convection within the anterior chamber on the ocular heat transfer
Authors: Ooi E. H. , Ng E. Y. K.
Published: August 2010

The aqueous humor inside the anterior chamber has been known to be in constant circulation. It is widely accepted that this flow is caused mainly by the thermal gradient inside the anterior chamber, which induces buoyancy. This generates natural convection inside the anterior chamber, which may affect the overall heat transfer inside the human eye. Nevertheless, most of the studies in the past that investigated the temperature distribution inside the human eye have not included this into their mathematical model. This study seeks to investigate the significance of natural convection inside the anterior chamber on the heat transfer inside the human eye. For this purpose, a two‐dimensional model of the anterior chamber is developed using the boundary element method. Copyright © 2010 John Wiley & Sons, Ltd.
Cyber Physical Socio Ecology
Authors: Shi Xiaoqing , Zhuge Hai
Published: August 2010

Exploring the laws of the nature and the rules of human society is the grand challenge of sciences. The Internet, Web, various communication networks and digital devices are connecting each other to form an enormous cyber space. The cyber space gradually connects the natural physical space via various cyber‐physical interfaces to form Cyber Physical Systems. Interacting with humans, Cyber Physical Systems will connect human society to form a new world—Cyber Physical Society. Humans' daily life and work will become increasingly relying on the new world. Billions of years' evolution creates the most elegant and efficient natural ecosystem. It will be ideal if the Cyber Physical Society can be an ecosystem that harmoniously evolves with society, economy, culture, sciences and technologies. The natural ecosystem gives us inspiration to ensure the harmony of the Cyber Physical Society. From ecosystem point of view, this paper proposes the notion, method, scientific issues, general architecture and resource management of Cyber Physical Society. The study of the Cyber Physical Socio Ecology (CPSE) could lead to a new branch of sciences. Copyright © 2010 John Wiley & Sons, Ltd.
Assessing service protocol adaptability based on protocol reduction and graph search
Authors: Zhou Zhangbing , Bhiri Sami , Zhuge Hai , Hauswirth Manfred
Published: August 2010

Given the inherent autonomy, heterogeneity, and continuous evolution of Web services, mismatches usually exist between service protocols. Adapters are typically used to reconcile these mismatches. Before synthesizing an adapter, a service requestor is often willing to assess whether her expected interactions can be conducted or not. The effort of synthesizing an adapter is beneficial only if the result of this assessment is positive. Previous effort analyzing service interactions focused on either (i) compatibility analysis for checking whether interactions can be conducted in a direct manner or (ii) adapter synthesization for reconciling mismatches. In this paper we propose a new kind of adaptability assessment that (i) determines whether two service protocols of a requestor and a provider are adaptable, (ii) computes an adaptation degree, and (iii) identifies conditions that determine when these two service protocols can be adapted. This adaptability assessment provides complementary criteria to the service requestor for selecting a suitable service protocol from a set of functionally equivalent candidates according to her requirements. Copyright © 2010 John Wiley & Sons, Ltd.
Energy‐aware scheduling of bag‐of‐tasks applications on master–worker platforms
Authors: Pineau Jean‐François , Robert Yves , Vivien Frédéric
Published: August 2010

We consider the problem of scheduling an application composed of independent tasks on a fully heterogeneous master–worker platform with communication costs. We introduce a bi‐criteria approach aiming at maximizing the throughput of the application while minimizing the energy consumed by participating resources. Assuming arbitrary super‐linear power consumption laws, we investigate different models, with energy overheads and memory constraints. Building upon closed‐form expressions for the uni‐processor case, we derive asymptotically optimal solutions for all models. Copyright © 2010 John Wiley & Sons, Ltd.
Special Issue: Euro‐Par 2009
Authors: Bougé Luc , Lengauer Christian
Published: August 2010

Preface for the special issue on Euro‐Par 2009. Copyright © 2010 John Wiley & Sons, Ltd.
Kinetics and Mechanisms for the Reactions of Ozone with Unsaturated Oxygenated Compounds
Authors: Al Mulla Ismael , Viera Lisa , Morris Rebecca , Sidebottom Howard , Treacy Jack , Mellouki Abdelwahid
Published: August 2010

Rate coefficients for the reaction of ozone with a series of unsaturated oxygenated compounds are determined in air at atmospheric pressure and (298±3) K. Rate data are obtained using both relative and absolute rate techniques, and the measured rate coefficients are found to be in good agreement. The results show that the reactivity of the compounds with respect to addition of ozone to the double bond is a function of the nature of the oxygenated substituent. Product distribution studies on the reactions provide information on the decomposition pathways for the primary ozonides, and on the effect of the oxygenated group on the relative importance of the degradation pathways. The results are discussed in terms of their importance in the atmospheric oxidation of unsaturated oxygenated compounds.
Metal‐Free Porphyrin‐Sensitized Mesoporous Titania Films For Visible‐Light Indoor Air Oxidation
Authors: Ismail Adel A. , Bahnemann Detlef W.
Published: August 2010

Transparent cubic mesoporous TiO2 films coated on soda‐lime glass have been developed. A metal free meso‐tetrakis(4‐sulfonatophenyl) porphyrin (TPPS) has been adsorbed on these TiO2 films from aqueous solutions. The results indicated that the obtained mesoporous TiO2 and 3D TPPS/TiO2 films are optically transparent and crack free (thickness ca. 200±20 nm). The introduction of the TPPS molecules has only a very small influence on the pore system and some limited pore blocking seems to occur. Transmission electron microscopy (TEM) images revealed that the adsorption of TPPS does not disrupt the meso order of TPPS/TiO2. The particle size of these TiO2 nanocrystals has been measured to be approximately 5–8 nm. TPPS/TiO2 photocatalysts, exhibiting regularly ordered mesopores, large surface area (ca. 102.5 cm2 cm−2), and specific pore volume of about 0.1 mm3 cm−2, show improved light‐harvesting efficiency as compared with other transparent TiO2 films. Employing the 3D TPPS/TiO2 photocatalyst, a quantum efficiency of 0.059 % has been obtained for the photodegradation of CH3CHO in the gas phase under visible‐light illumination. Recycling tests demonstrated that the newly synthesized photocatalyst was quite stable during this gas–solid heterogeneous photocatalytic process because no significant decrease in photocatalytic activity was observed even after being used repetitively up to five times. Therefore, the newly synthesized transparent 3D TPPS/TiO2 photocatalysts can potentially be applied for low‐cost air purification and self‐cleaning applications.
Novel stability criteria of Cohen–Grossberg neural networks with time‐varying delays
Authors: Zheng Cheng‐De , Shan Qi‐He , Wang Zhanshan
Published: August 2010

In this paper, a class of Cohen–Grossberg neural networks with time‐varying delays is investigated. Based on several new Lyapunov–Krasovskii functionals, by employing the homeomorphism mapping principle, the Halanay inequality, a nonlinear measure approach and linear matrix inequality techniques, several delay‐independent sufficient criteria are obtained for the existence, uniqueness and globally exponential stability of considered neural networks. Without assuming the boundedness and monotonicity of activation functions, the obtained conditions generalize some previous results in the literature. Two examples are also given to show the less conservativeness of the obtained conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Design approach for high‐bandwidth low‐power three‐stage operational amplifiers
Authors: Pugliese A. , Amoroso F. A. , Cappuccino G. , Cocorullo G.
Published: August 2010

A new design approach to optimize the frequency compensation network of three‐stage operational amplifiers (op‐amps) is presented.

The proposed criterion is aimed at maximizing the bandwidth of well‐established three‐stage op‐amps using Nested‐Miller Compensation with feedforward tranconductance stage and nulling resistor (NMCFNR). As shown by design examples in a commercial 0.35‐µm CMOS technology, the proposed approach allows the amplifier bandwidth to be enhanced significantly with respect to that resulting from using existing design strategies for NMCFNR op‐amps.

It is also demonstrated that NMCFNR op‐amps, designed according to the proposed method, even guarantee larger values of the gain‐bandwidth product than three‐stage amplifiers using more complicated frequency compensation techniques, such as AC boosting compensation or damping‐factor control frequency compensation. Copyright © 2010 John Wiley & Sons, Ltd.
Deposition of Large‐Area and Protective Diamond‐like Carbon Coatings on Glass Substrates by Low‐Pressure Dielectric Barrier Discharges
Authors: Niu Jinhai , Liu Dongping , Ou Yangbiao , You Yuting , Yu Naisen
Published: August 2010

Large‐area (370mm×500mm) diamondlike carbon (DLC) films were deposited on the glass substrate by low‐pressure dielectric barrier discharges. The deposited DLC films were hard, homogeneous and extremely smooth. The DLC film deposited on the large‐area glass can be potentially used as a scratch resistant and corrosion barrier layer.
Improved detection of nicotinamide adenine dinucleotide phosphate oscillations within human neutrophils
Authors: Clark Andrea J. , Romero Roberto , Petty Howard R.
Published: August 2010

Kinetic studies of nicotinamide adenine dinucleotide phosphate autofluorescence have been conducted in adherent neutrophils using an improved microscopic photometry system incorporating low noise excitation and detection systems. Dynamic autofluorescence oscillations were found with periods ranging from ∼4 min to ∼10 s. The largest portion of the population of oscillating neutrophils (32%) had periods near 2 min. The next largest group at 25% exhibited periods of 1 min or less. These oscillations could not be accounted for by instrument artifacts, cell shape changes away from the focal plane, or other factors. They disappeared when detergent was added to oscillating cells. Higher‐frequency oscillations disappeared as cells changed shape, indicating a correlation between these two processes. This approach provides a reliable method to monitor this cellular property. © 2010 International Society for Advancement of Cytometry
An efficient identity‐based protocol for private matching
Authors: Zhong Sheng , Chen Tingting
Published: August 2010

An important application of the Internet is that people can find partners satisfying their requirements from the huge number of users. In this paper, we present a cryptographic protocol for private matching, in which a user finds her desired partners without revealing her requirements, and the potential partners do not need to reveal their profiles. An additional advantage of our protocol is that it is identity‐based, which means the involved parties do not need to have a priori knowledge of each other's public keys; as long as they know each other's identities, the protocol can be executed. Copyright © 2010 John Wiley & Sons, Ltd.
Support of multiple content variants in the multimedia broadcast/multicast service
Authors: Xylomenos George , Katsaros Konstantinos , Tsakanikas Vasilis
Published: August 2010

The Multimedia Broadcast/Multicast Service (MBMS) was designed to enable the mass distribution of multimedia content in 3rd Generation and beyond cellular networks. If such services are to become commercially viable, they must be able to efficiently support widely heterogeneous user requirements, for example, due to terminal limitations and cost constraints. This paper presents an MBMS extension that allows multiple variants of the same content to be economically distributed to heterogeneous receivers, explicitly taking into account the possibility of using either dedicated or common radio channels. We describe our extended multiple content variant MBMS model by explaining the modifications that it imposes on the standard MBMS model, as well as the manner in which it can be combined with layered coding. We also present an analytical evaluation of our approach against alternatives based on the standard MBMS in terms of control and user plane overhead, and compare the analytical predictions with detailed simulation results. Both the analysis and the simulations indicate that our proposal can indeed satisfy heterogeneous user requirements, while consuming considerably lower resources than the standard‐based alternatives. Copyright © 2010 John Wiley & Sons, Ltd.
Essential genes for astroglial development and axon pathfinding during zebrafish embryogenesis
Authors: Barresi Michael J.F. , Burton Sean , Dipietrantonio Kristina , Amsterdam Adam , Hopkins Nancy , Karlstrom Rolf O.
Published: August 2010

The formation of the central nervous system depends on the coordinated development of neural and glial cell types that arise from a common precursor. Using an existing group of zebrafish mutants generated by viral insertion, we performed a “shelf‐screen” to identify genes necessary for astroglial development and axon scaffold formation. We screened 274 of 315 viral insertion lines using antibodies that label axons (anti‐Acetylated Tubulin) and astroglia (anti‐Gfap) and identified 25 mutants with defects in gliogenesis, glial patterning, neurogenesis, and axon guidance. We also identified a novel class of mutants affecting radial glial cell numbers. Defects in astroglial patterning were always associated with axon defects, supporting an important role for axon‐glial interactions during axon scaffold development. The genes disrupted in these viral lines have all been identified, providing a powerful new resource for the study of axon guidance, glio‐ and neurogenesis, and neuron‐glial interactions during development of the vertebrate CNS. Developmental Dynamics 239:2603–2618, 2010. © 2010 Wiley‐Liss, Inc.
Expression, functional, and structural analysis of proteins critical for otoconia development
Authors: Xu Yinfang , Zhang Hui , Yang Hua , Zhao Xing , Lovas Sándor , Lundberg Yunxia (Yesha) Wang
Published: August 2010

Otoconia, developed during late gestation and perinatal stages, couple mechanic force to the sensory hair cells in the vestibule for motion detection and bodily balance. In the present work, we have investigated whether compensatory deposition of another protein(s) may have taken place to partially alleviate the detrimental effects of Oc90 deletion by analyzing a comprehensive list of plausible candidates, and have found a drastic increase in the deposition of Sparc‐like 1 (aka Sc1 or hevin) in Oc90 null versus wt otoconia. We show that such up‐regulation is specific to Sc1, and that stable transfection of Oc90 and Sc1 full‐length expression constructs in NIH/3T3 cells indeed promotes matrix calcification. Analysis and modeling of Oc90 and Sc1 protein structures show common features that may be critical requirements for the otoconial matrix backbone protein. Such information will serve as the foundation for future regenerative purposes. Developmental Dynamics 239:2659–2673, 2010. © 2010 Wiley‐Liss, Inc.
Zebrafish notch signalling pathway mutants exhibit trunk vessel patterning anomalies that are secondary to somite misregulation
Authors: Therapontos Christina , Vargesson Neil
Published: August 2010

The Notch signalling pathway mutants, after‐eight (aei), beamter (bea), and deadly‐seven (des) have previously been used to study somitogenesis and neurogenesis. Notch signalling has also been shown to have roles in vascular development. However, vascular development in each of these three Notch mutants has not been described, and so their potential usefulness for further understanding the role of Notch signalling in angiogenesis is unknown. Here we demonstrate each of the mutants also exhibit vascular defects in inter‐somitic vessel (ISV) positioning and patterning. Ectopic filopodia were also observed on the ISVs of the mutants. Ectopic filopodia are not due to loss of dll4. Somite expression of known vascular guidance cues, efnb2, sema3a2, and plexinD1 are disrupted, suggesting that the ISV vascular phenotype is due to disruption of these cues. Developmental Dynamics 239:2761–2768, 2010. © 2010 Wiley‐Liss, Inc.
Sox9‐expressing precursors are the cellular origin of the cruciate ligament of the knee joint and the limb tendons
Authors: Soeda Tsunemitsu , Deng Jian Min , de Crombrugghe Benoit , Behringer Richard R. , Nakamura Takashi , Akiyama Haruhiko
Published: August 2010

Sox9 expression defines cell progenitors in a variety of tissues during mouse embryogenesis. To establish a genetic tool for cell‐lineage tracing and gene‐function analysis, we generated mice in which the CreERT2 gene was targeted to the endogenous mouse Sox9 locus. In Sox9CreERT2/+;R26R embryos, tamoxifen activated Cre recombinase exclusively in Sox9‐expressing tissues. To determine the suitability of this mouse line for developmental stage‐specific gene recombination, we investigated the cellular origins of the cruciate ligaments of the knee joint and the limb tendons, in which precursor cells have not been defined. The cells in these tissues were labeled after tamoxifen treatment before or at the stage of chondrogenic mesenchymal condensation, indicating that ligament and tendon cells originated from Sox9‐expressing cells and that cell fate determination occurred at mesenchymal condensation. This mouse line is a valuable tool for the temporal genetic tracing of the progeny of, and inducible gene modification in Sox9‐expressing cells. genesis 48:635–644, 2010. © 2010 Wiley‐Liss, Inc.
Self‐Assembly and the Properties of a Highly Oriented Hierarchical Nanobelt–Nanoprism Array of Ternary Oxide Zn–In–O
Authors: Pan Nan , Xue Haizhou , Huang Jinhua , Zhang Guanghui , Wu Yukun , Li Ming , Wang Xiaoping , Hou Jianguo
Published: August 2010

A highly oriented, well‐aligned hierarchical Zn–In–O nanobelt–nanoprism array was synthesized by vapor‐phase transport and condensation using GaN epilayer as the substrate. The upper nanobelts are found to be ZnO:In with an average Zn/In molar ratio of approximately 9:1, and the subjacent nanoprisms are found to be In2O3(ZnO)m (m = 2, 3, 4, and 5) structures. During self‐assembly, the nanoprisms are vertically grown on GaN and well aligned along the superlattice stacking direction, upon which each nanobelt is horizontally grown along its [10–10] direction. The spatially resolved cathodoluminescence spectra collected on individual hierarchical nanostructures clearly show characteristics for the ZnO:In nanobelt and for the In2O3(ZnO)m nanoprism, which are distinctly different from the emissions of the undoped ZnO nanorod. I‐V measurements on individual nanobelts reveal good conductivity over 103 S m–1 and high electron concentration of 1019–1020 cm–3. This bottom‐up self‐assembled, highly oriented, and well‐aligned hierarchical nanoarray may find applications in newly emerging vertically integrated nanoarray circuits.
Novel Bi‐ and Trinuclear Gallium Halides and Hydrides with Acyclic and Bicyclic Guanidinate Substituents: Synthesis and Reactivity
Authors: Rudolf Daniel , Kaifer Elisabeth , Himmel Hans‐Jörg
Published: August 2010

We report on the synthesis and characterization of new molecular Ga halides and hydrides with acyclic guanidinate substituents with bicyclic guanidinate substituents. Acyclic guanidinates were found to adopt terminal bonding modes like in the dimeric GaII compound [(iPr2N)C(NiPr)2GaI]2. In contrast, bicyclic guanidinates prefer bridging bonding modes. Hence, the reaction between Me3N·GaH3 and htbo (1,4,6‐triazabicyclo[3.3.0]oct‐4‐ene) affords the binuclear GaIII hydride [H2Ga(μ‐tbo)]2. This new hydride turned out to be unstable in solution at 25 °C, dihydrogen is slowly eliminated. In the solid state, however, the hydride is stable up to 80 °C. The thermodynamic properties of this and similar dehydrogenation reactions were studied my means of quantum chemical calculations. With Ga2H5(μ3‐O)(μ‐tbn)2 and Ga2H5(μ3‐O)(μ‐hpp)2, two new hydrides were synthesized which can be regarded as the first hydrolysis intermediates of binuclear Ga hydrides with bridging guanidinate substituents.
The Participation of 2H‐Pyran‐2‐ones in [4+2] Cycloadditions: An Experimental and Computational Study
Authors: Štefane Bogdan , Perdih Andrej , Pevec Andrej , Šolmajer Tomaž , Kočevar Marijan
Published: August 2010

Experimental and computational DFT studies of the Diels–Alder (DA) reaction mechanism for the series of 2H‐pyran‐2‐ones 1 and non‐symmetrically substituted alkynes 2, 10, and 11 were undertaken. Several 2H‐pyran‐2‐ones 1 were treated with N,N‐diethylpropynamine (2). The results point toward a polar and asynchronous two‐step mechanism that is in line with the characteristics of a polar Diels–Alder (P‐DA) reaction mechanism.5 Unexpected formation of minor products 4a–d during the reaction of 1 with 2 can be rationalized by considering the easily passable torsion barrier around the newly formed C–C bond that enables two different cyclization modes. The charge transfer (CT) and global reactivity indices analyses demonstrated that in these reactions 2H‐pyran‐2‐ones act as electrophiles and N,N‐diethylpropynamine (2) acts as a nucleophile reaction partner. The introduction of electron‐withdrawing carboxylic substituents on the dienophiles 10 and 11 shifts the DA reaction with 2H‐pyran‐2‐ones to a less polar and more synchronous concerted reaction mechanism. Calculated CT as well as values of the global electrophilicity and nucleophilicity N indexes revealed that 2H‐pyran‐2‐ones act in this case as nucleophiles and reacting dienophiles 10 and 11 as electrophiles. The results are consistent with the experimental data and kinetic analyses, thus providing valuable insights into 2H‐pyran‐2‐one chemistry and paving the way for an efficient synthesis of highly functionalized benzene derivatives as well as broadening the mechanistic understanding of these highly versatile reactions.
Enantiodivergent Chemoenzymatic Synthesis of 4‐Hydroxypiperidine Alkaloids
Authors: Bartali Laura , Casini Andrea , Guarna Antonio , Occhiato Ernesto G. , Scarpi Dina
Published: August 2010

An efficient chemoenzymatic synthesis of both enantiomers of fagomine, as well as ofcisandtrans‐4‐hydroxypipecolic acid is reported. The synthesis starts from commercial δ‐valerolactam which, after a Pd‐catalyzed methoxycarbonylation of the corresponding vinyl phosphate, is subjected to allylic oxidation to give a racemic 4‐hydroxytetrahydropyridine derivative in 57 % overall yield. This product is resolved by an enzyme‐catalyzed esterification using immobilized lipases fromCandida antarctica(Novozym 435) andBurkholderia cepacia(lipase PS Amano IM). The latter provides the correspondingResters and theSalcohol in 95 and 94 %ee, respectively. TheSalcohol is then converted intoL‐fagomine by a stereoselective hydroboration/oxidation as key steps and thecis‐(2R,4S)‐4‐hydroxypipecolic acid by stereoselective hydrogenation. The correspondingD‐fagomine andcis‐(2S,4R)‐4‐hydroxypipecolic acid, as well astrans‐(2R,4R)‐4‐hydroxypipecolic acid can be prepared by the same strategy after hydrolysis of theRester obtained by kinetic resolution.
Some Possibilities and Limitations of Contactless Impedimetric Determinations of Organic Liquids in Aqueous Solutions. The Interference from Ionic Compounds
Authors: Opekar František , Štulík Karel , Fišarová Michaela
Published: August 2010

The possibilities of impedimetric determinations of organic liquids in mixtures with aqueous solutions have been studied in detail, using a planar capacitor cell combined with multivibrator and operational amplifier circuits functioning as a differentiator and a system of dioxane with aqueous solutions of alkali halides. The experimental values have been compared with a simple model and the detector response has been characterized. The behaviour of the detection cell can be reliably predicted on this basis. This approach permits extremely simple, rapid and cheap analyses of binary liquid mixtures, however, it suffers from a serious limitation in that the overall electric conductivity of the mixture must be low.
The Signal‐Enhanced Label‐Free Immunosensor Based on Assembly of Prussian Blue‐SiO2 Nanocomposite for Amperometric Measurement of Neuron‐Specific Enolase
Authors: Zhong Zhaoyang , Shan Jinlu , Zhang Zhiming , Qing Yi , Wang Dong
Published: August 2010

A signal‐enhanced label‐free electrochemical immunosensor was constructed by the employment of Prussian blue doped silica dioxide (PB‐SiO2) nanocomposite. At first, PB‐SiO2 nanocomposite which was produced by using a microemulsion method was used to obtain a nanostructural monolayer on a glassy carbon electrode (GCE) surface. Next amino‐functionalized interface were prepared by self‐assembling 3‐aminopropyltriethoxy silane (APTES) on the PB‐SiO2 nanoparticle surface. Then chitosan stabled gold nanoparticle (CS‐nanoAu) was subsequently attached, while the entire surface was finally loaded with neuron‐specific enolase antibody (anti‐NSE) via the adsorption of gold nanoparticle. The sensitivity of the proposed immunosensor has greatly improved as the PB‐SiO2 nanostructural sensing film provides plenty of active sites which might catalyze the reduction of H2O2. The immunosensor exhibited good linear behavior in the concentration range from 0.25–5.0 and 5.0–75 ng/mL for the quantitative analysis of neuron‐specific enolase (NSE), a putative serum marker of small‐cell lung carcinoma (SCLC), with a limit of detection of 0.08 ng/mL. The resulting NSE immunosensor showed high sensitivity and long‐term lifetime which can be attributed to the extremely high catalytic activity and biocompatibility of CS‐nanoAu/APTES/PB‐SiO2 nanostructural multilayers.
Development of a Xanthine Oxidase Modified Amperometric Electrode for the Determination of the Antioxidant Capacity
Authors: Cortina‐Puig Montserrat , Scangas Anastasia C. H. , Marchese Zachary S. , Andreescu Silvana , Marty Jean‐Louis , Calas‐Blanchard Carole
Published: August 2010

This paper describes the development of a xanthine oxidase/poly‐m‐phenylenediamine (XOD‐PPD)‐modified electrode. The biosensor was constructed by encapsulating XOD in a sol‐gel matrix deposited onto a platinum based screen‐printed electrode functionalized with a permselective PPD membrane. The hydrogen peroxide generated as a final product of the enzymatic reaction between the hypoxanthine and the XOD or by the spontaneous dismutation of superoxide radicals was selectively monitored at +700 mV. The use of a highly selective PPD layer blocked the nonspecific oxidation of other oxidizable molecules. Finally the biosensor was applied to the determination of the antioxidant capacity of acetylsalicylic acid.
Gold Nanoparticles Electrodeposited on Ordered Mesoporous Carbon as an Enhanced Material for Nonenzymatic Hydrogen Peroxide Sensor
Authors: Wang Lixia , Bo Xiangjie , Bai Jing , Zhu Liande , Guo Liping
Published: August 2010

A facile and controllable electrodeposition method was developed to directly attach gold nanoparticles (GNPs) on ordered mesoporous carbon (OMC). The GNPs on OMC substrate were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectrometer (XPS), respectively. A nonenzymatic hydrogen peroxide (H2O2) sensor was fabricated on GNPs‐OMC/GCE. The sensor demonstrated a fast amperometric response (2.5 s), a wide linear range toward H2O2 concentrations between 2.0×10−6 and 3.92×10−3 M (R=0.999), and a low detection limit of 0.49 µM (S/N=3). Moreover, it exhibited good reproducibility and long‐term stability. The excellent electrocatalytical activity might be attributed to the synergistic effect of OMC and GNPs.
Polyaniline/Single‐Walled Carbon Nanotubes Composite Based Triglyceride Biosensor
Authors: Dhand Chetna , Solanki Pratima R. , Datta Monika , Malhotra B. D.
Published: August 2010

Nanocomposite film comprising of polyaniline (PANI) and single walled carbon nanotubes (SWCNT) has been fabricated onto indium‐tin‐oxide (ITO) coated glass plate using electrophoretic technique. Co‐immobilization of glycerol dehydrogenase (GDH) and lipase (LIP) has been done via N‐ethyl‐N′‐(3‐dimethylaminopropyl) carbodiimide and N‐hydroxysuccinimide chemistry to explore its application for triglyceride (tributyrin) sensing. Response studies have been done using linear sweep voltammetry revealing that LIP‐GDH/PANI‐SWCNT‐TB/ITO bioelectrode can detect tributyrin in the range of 50 to 400 mg dL−1 with low Michaelis–Menten constant of 1.138 mM, improved response time of 12 s, high sensitivity as 4.28×10−4 mA mg−1 dL and storage stability of about 13 weeks.
Study of electromigration effects on a pH boundary during the on‐line electrokinetic preconcentration by capillary electrophoresis
Authors: Vítková Kateřina , Petr Jan , Maier Vítězslav , Znaleziona Joanna , Ševčík Juraj
Published: August 2010

A contribution to the description of electrokinetic effects on the pH boundary formed by sodium borate pH 9.5 and sodium phosphate pH 2.5 electrolytes for on‐line preconcentration of weak acids is presented in this article. Simulations of electrokinetic injections together with experimental studies using contactless conductivity detection verified that the preconcentration is induced mainly by dissociation changes of analytes on the pH boundary and transient ITP state. Moreover, a study of the addition of organic solvent to the injection electrolyte was performed with impressive results. Subnanomolar LODs of hydroxybenzoic acids were achieved with 80% of methanol in the injection electrolyte which represents more than 70 000‐fold preconcentration in comparison with classical CZE method.
Parallel separations using capillary electrophoresis on a multilane microchip with multiplexed laser‐induced fluorescence detection
Authors: Nikcevic Irena , Piruska Aigars , Wehmeyer Kenneth R. , Seliskar Carl J. , Limbach Patrick A. , Heineman William R.
Published: August 2010

Parallel separations using CE on a multilane microchip with multiplexed LIF detection is demonstrated. The detection system was developed to simultaneously record data on all channels using an expanded laser beam for excitation, a camera lens to capture emission, and a CCD camera for detection. The detection system enables monitoring of each channel continuously and distinguishing individual lanes without significant crosstalk between adjacent lanes. Multiple analytes can be determined in parallel lanes within a single microchip in a single run, leading to increased sample throughput. The pKa determination of small molecule analytes is demonstrated with the multilane microchip.
Conformation dependence of DNA electrophoretic mobility in a converging channel
Authors: Liao Wei‐Ching , Watari Nobuhiko , Wang Shengnian , Hu Xin , Larson Ronald G. , Lee Ly James
Published: August 2010

The electrophoresis of λ‐DNA is observed in a microscale converging channel where the center‐of‐masses trajectories of DNA molecules are tracked to measure instantaneous electrophoretic (EP) mobilities of DNA molecules of various stretch lengths and conformations. Contrary to the usual assumption that DNA mobility is a constant, independent of field and DNA length in free solution, we find DNA EP mobility varies along the axis in the contracting geometry. We correlate this mobility variation with the local stretch and conformational changes of the DNA, which are induced by the electric field gradient produced by the contraction. A “shish‐kebab” model of a rigid polymer segment is developed, which consists of aligned spheres acting as charge and drag centers. The EP mobility of the shish‐kebab is obtained by determining the electrohydrodynamic interactions of aligned spheres driven by the electric field. Multiple shish‐kebabs are then connected end‐to‐end to form a freely jointed chain model for a flexible DNA chain. DNA EP mobility is finally obtained as an ensemble average over the shish‐kebab orientations that are biased to match the overall stretch of the DNA chain. Using physically reasonable parameters, the model agrees well with experimental results for the dependence of EP mobility on stretch and conformation. We find that the magnitude of the EP mobility increases with DNA stretch, and that this increase is more pronounced for folded conformations.
Precautions to improve the accuracy of quantitative determinations of biomarkers in clinical diagnostics
Authors: Ghasemzadeh Nasim , Wilhelmsen Tore W. , Nyberg Fred , Hjertèn Stellan
Published: August 2010

Although protein biomarkers have a great potential as biomarkers for diagnosis of diseases, they are seldom used in hospitals. There are many reasons for this, for instance, the difficulties to (i) find a biomarker for which the concentration in body fluids clearly differs between patients and healthy subjects, (ii) attain purification of the biomarker close to 100%, which is required for production of conventional protein antibodies as well as artificial gel antibodies for selective capture of a biomarker, (iii) design a standard curve for rapid and accurate determination of the concentration of the biomarker in the body fluid because of adsorption of the biomarker onto vials, pipettes, etc., (iv) determine accurately the sample volume delivered by a pipette, (v) avoid polymerization of the biomarker upon storage and to decide whether it is in the form not only of monomers, but also of dimers, trimers, etc., in the native state, (vi) determine the degree of possible glycosylation and amidation of the biomarker and (vii) decide whether glycosylation and amidation positively or negatively affects the possibility to use the protein as a biomarker. In this article, we discuss in quantitative terms the difficulties (iii–vii) and how to overcome them, which also may help to overcome the difficulty (ii), which in turn minimizes difficulty (i).
Metal-induced shifts in benthic macroinvertebrate community composition in Andean high altitude streams
Authors: Loayza-Muro Raúl A. , Elías-Letts Rafaela , Marticorena-Ruíz Jenny K. , Palomino Edwin J. , Duivenvoorden Joost F. , Kraak Michiel H.S. , Admiraal Wim
Published: August 2010

High altitude creates unique challenging conditions to biota that limit the diversity of benthic communities. Because environmental pollution may add further stress to life at high altitude, the present study explored the effect of metal pollution on the macroinvertebrate community composition in Andean streams between 3,500 to 4,500 meters above sea level (masl) during wet and dry seasons. At polluted sites, showing a high conductivity and a low pH, metal concentrations (e.g., Al, 13.07 mg/L; As, 3.49 mg/L; Mn, 19.65 mg/L; Pb, 0.876 mg/L; Zn, 16.08 mg/L) ranged from 8-fold up to 3,500-fold higher than at reference sites. The cumulative criterion unit allowed quantifying the potential toxicity of metal mixtures at the contaminated sites. Principal component analysis of physical chemical variables showed that reference sites were more likely to be structured by transparency, water discharge, and current velocity, while polluted sites appeared to be determined by metals and conductivity. Canonical correspondence analysis indicated a strong influence of highly correlated metals in structuring invertebrate communities, which were dominated by dipterans, coleopterans, collembolans, and mites at polluted sites. At reference sites crustaceans, ephemeropterans, plecopterans, and trichopterans were the most representative taxa. We concluded that severe metal pollution induced changes in macroinvertebrate community composition in high-altitude Andean streams, with a replacement of sensitive taxa by more tolerant taxa. Yet relatively species-rich communities persisted under harsh conditions. Environ. Toxicol. Chem. 2010;29:2761–2768. © 2010 SETAC
Developmental triclosan exposure decreases maternal and neonatal thyroxine in rats
Authors: Paul Katie B. , Hedge Joan M. , DeVito Michael J. , Crofton Kevin M.
Published: August 2010

Disruption of maternal thyroid hormones during fetal developmental may result in irreversible neurological consequences in offspring. The present study tested the hypothesis that perinatal triclosan exposure of dams decreases thyroxine in dams and offspring prior to weaning. Pregnant Long–Evans rats received triclosan by oral gavage (0–300 mg/kg/d) in corn oil from gestational day (GD)6 through postnatal day (PND)21. Serum was obtained from pups on PND4, 14, and 21, and from dams on PND22. Serum thyroxine (T4) was reduced 31% in dams on PND22. In pups, a unique pattern of hypothyroxinemia was observed; serum T4 decreased 27% in PND4 pups with no significant reduction observed on PND14 or PND21. Comparable reductions of approximately 30% in serum T4 at 300 mg/kg/d for dams and PND4 neonates and a lack of effect at PND14 and PND21 suggest that toxicokinetic or toxicodynamic factors may have contributed to a reduced exposure or a reduced toxicological response during the lactation period. Environ. Toxicol. Chem. 2010;29:2840–2844. © 2010 SETAC
Fire suppressing performance of superfine potassium bicarbonate powder
Authors: Kuang Kaiqian , Chow W. K. , Ni Xiaomin , Yang Donglei , Zeng Wenru , Liao Guangxuan
Published: August 2010

Fire suppression effectiveness of a new kind of dry powder based on potassium bicarbonate was studied in this paper. The powder consisted of superfine potassium bicarbonate and some organic and inorganic additives, which was denoted as ‘K‐powder’. The physical and chemical characteristics of the K‐powder were characterized by a series of techniques of X‐ray diffraction, scanning electron microscopy, Fourier transforms infrared (FTIR) and thermal gravity analysis, etc. Performance of the new potassium‐based powder in fire suppression was studied by laboratory‐scale experiments, which exhibited much superior fire suppression efficacy than that of the commercial bicarbonate powder. Such improvements could be reasonably ascribed to the special chemical composition, microstructure and radiation effect on the mechanisms. The preparation, fire suppression and possible fire‐extinguishing mechanisms were studied in detail. Copyright © 2010 John Wiley & Sons, Ltd.
Multistage metamorphism and deformation in high‐pressure metabasites of the northern Adula Nappe Complex (Central Alps, Switzerland)
Authors: Zulbati Fabio
Published: August 2010

Metabasites from the northern Adula Nappe Complex (ANC) display a complex microstructural evolution recording episodes of deformation and metamorphic re‐equilibration that were obliterated in the surrounding phengite‐bearing schists. Pre‐D1 and D1 deformation episodes are preserved as mineral inclusions within garnet cores of some amphibole‐bearing eclogites and record high‐temperature greenschist‐/amphibolite‐facies conditions. D2 produced an eclogite‐facies foliation which developed at 580 ± 70°C and 19 ± 3 kbar. D3 was a composite deformation episode which can be divided into three sub‐episodes D3m, D3a and D3b which occurred as the metamorphism evolved from post‐eclogitic high‐pressure and low‐temperature conditions through to amphibolite‐facies conditions at 590 ± 30°C and 11.7 ± 1.3 kbar. The D3 deformation episode was responsible for the development of the S3 regional‐scale foliation in the surrounding schists, whilst D4 caused the development of an S4 greenschist foliation. The composite nature of the D3 episode indicates that rocks of the northern ANC experienced a protracted post‐eclogitic structural reworking and that the current structure of this part of the Alps is a late‐Alpine feature. Copyright © 2010 John Wiley & Sons, Ltd.