bluuebunny/crossref_metadata_2025 huggingface dataset:
Formal and informal meaning from documents through skeleton sentences
Authors: Marcoux Yves , Sperberg-McQueen C. M. , Huitfeldt Claus
Published: August 2009

In [Sperberg-McQueen et al. 2000a], Sperberg-McQueen et al. describe a framework in which the semantics of a structured document is represented by the set of inferences (statements) licensed by the document, that is, statements which can be considered to hold on the basis of the document. The authors suggest that an adequate set of basic inferences can be generated from the document itself by a fairly simple skeleton sentence and deictic expression mechanism. These ideas were taken up and developed in various ways and contexts in later work (see for example [Sperberg-McQueen et al. 2002]) and came to be called the “Formal tag-set description” approach (FTSD). The approach is independent of any particular logical system, and the possibility that the statements licensed by a document be in natural language has been mentioned and exemplified, though not to a large extent.

With a different set of preoccupations in mind (namely, providing semantic support to an author during the document creation process), Marcoux introduced in [Marcoux 2006] intertextual semantics (IS), a framework in which the meaning of a document is entirely and exclusively represented by natural language segments.

In this paper, we compare the IS and FTSD approaches, and argue that the insights into the meaning of a document supplied by the two approaches actually complement each other. We give a number of concrete examples of increasing complexity, including the set of formal and informal statements derivable in each case, to substantiate our claim.
Sometimes a question of scale
Authors: Sperberg-McQueen C. M.
Published: August 2009

Reflections on size, scale, scaleability, and value.
TEI Feature Structures as a Representation Format for Multiple Annotation and Generic XML Documents
Authors: Stegmann Jens , Witt Andreas
Published: August 2009

Feature structures are mathematical entities (rooted labeled directed acyclic graphs) that can be represented as graph displays, attribute value matrices or as XML adhering to the constraints of a specialized TEI tag set. We demonstrate that this latter ISO-standardized format can be used as an integrative storage and exchange format for sets of multiple annotation XML documents. This specific domain of application is rooted in the approach of multiple annotations, which marks a possible solution for XML-compliant markup in scenarios with conflicting annotation hierarchies. A more extreme proposal consists in the possible use as a meta-representation format for generic XML documents. For both scenarios our strategy concerning pertinent feature structure representations is grounded on the XDM (XQuery 1.0 and XPath 2.0 Data Model). The ubiquitous hierarchical and sequential relationships within XML documents are represented by specific features that take ordered list values. The mapping to the TEI feature structure format has been implemented in the form of an XSLT 2.0 stylesheet. It can be characterized as exploiting aspects of both the push and pull processing paradigm as appropriate. An indexing mechanism is provided with regard to the multiple annotation documents scenario. Hence, implicit links concerning identical primary data are made explicit in the result format. In comparison to alternative representations, the TEI-based format does well in many respects, since it is both integrative and well-formed XML. However, the result documents tend to grow very large depending on the size of the input documents and their respective markup structure. This may also be considered as a downside regarding the proposed use for generic XML documents. On the positive side, it may be possible to achieve a hookup to methods and applications that have been developed for feature structure representations in the fields of (computational) linguistics and knowledge representation.
Standards considered harmful
Authors: Usdin B. Tommie
Published: August 2009

Standards and shared specifications allow us to share data, build general purpose tools, and significantly reduce training and customization costs and startup time. That is, the use of appropriate specifications can help us reduce costs, reduce startup time, and increase quality, usability, and reusability of content. Some vigorous standards proponents insist that the more standards used the better. To them I say “mind your own business and let me mind my own store”. They argue that using standards is always the right thing to do, because it enables re-use and interchange. Maybe so. But adoption of a standard that supports an activity that is not central to your mission is a distraction, an unwarranted expense, a bad idea.
Investigating the streamability of XProc pipelines
Authors: Walsh Norman
Published: August 2009

XProc: An XML Pipeline Language is a specification being developed by the W3C for describing a sequence of XML operations performed over a set of input documents. Not all of the steps in XProc are known to streamable and consequently, the XProc specification does not require implementations to support streaming.

It's an open question whether or not a streaming implementation would be likely to achieve significant performance improvements over a similar non-streaming implementation. Using data collected from real-world pipelines, this paper examines that question.
Graciously handling a level of change in a complex specification
Authors: McCay Charlie , Odling-Smee Michael , Waller Joseph , Wrightson Ann
Published: August 2009

The concept of a flexible and yet also breakable interface is central to successful configuration and version management for a messaging specification. Changes which are made to a message or message definition should not affect systems or design teams that are not concerned with the subject of the change. However, changes causing unexpected behaviour or misinterpretation of a message should ‘break the interface’ thus making it impossible for systems to unknowingly use a changed message in a way which may hold clinical safety or other risks. Achieving these features in a complex specification with a diverse implementation community is not a simple matter. However, there are several measures that could be beneficial.

Applying the kind of configuration management discipline that is well known for complex software artefacts to the development of a complex specification is likely to be cost-effective, even though the tools available are less mature. A combined strategy of representing key aspects of design configuration not only within the specification artefacts published to the implementation community, but also as a matrix documenting expected impacts, and within message instances in live operation, is also promising as a way to enable gracious handling of change.
Visual Designers: Those XML tools with no angle bracket at all!
Authors: Cau Jean Michel , Zergaoui Mohamed
Published: August 2009

Is the future of XML planned to be without XML? Visual tools are everywhere and XProc might be the first XML dialect to be immediately available with its visual editor. After erratic evolutions, visual tools have become more and more precise (even HTML+CSS tools are now very powerful), and have become more and more main stream. Could we imagine dealing with XML Schema without decent Visual Tools? We will show in this presentation an overview of where we do XML without seeing any angle bracket and the places where we expect to have some equivalent tools soon.
TNTBase: Versioned Storage for XML
Authors: Zholudev Vyacheslav , Kohlhase Michael
Published: August 2009

Version control systems like CVS and Subversion have transformed collaboration workflows in software engineering and made possible the globally distributed project teams we know from the Open Source phenomenon. On the other hand, XML is coming of age as a basis for document formats, and even though XML as a text-based format is amenable to version control in principle, the fact that version control systems work on files makes difficult the integration of fragment access techniques like XPath, XQuery that are currently revolutionizing XML workflows.

In this paper we present the TNTBase system, an open-source versioned XML database obtained by integrating Berkeley DB XML into the Subversion Server. The system is intended as a basis for collaborative editing and sharing XML-based documents. It integrates versioning and fragment access needed for fine-granular document content management.
Efficient scripting
Authors: Lee David A. , Walsh Norman
Published: August 2009

The efficiency and performance of individual XML operations such as parsing, processing (XSLT, XQuery) and serialization, and the merits of different in-memory document representations, have been widely discussed. However, real world uses cases often involve many operations orchestrated using a scripting environment. The performance of the scripting environment can often overshadow any performance gains in individual operations. In an exploration of real world scripting, we compare performance of several scripting languages and techniques on a set of typical XML operations such as generation of a table of contents and conditionally accessing non-XML files identified in XML documents. Based on performance results, we suggest best practices for scripting XML processes. Scripting languages compared include DOS Shell (CMD.EXE), Linux Shell (bash), XMLSH, and XProc (calabash). These are run (where possible) on multiple operating systems: Windows XP, Linux, and Mac/OS.
The XML Chip at 6 Years
Authors: Leventhal Michael , Lemoine Eric
Published: August 2009

The XML chip is now more than six years old. The diffusion of this technology has been very limited, due, on the one hand, to the long period of evolutionary development needed to develop hardware capable of accelerating a significant portion of the XML computing workload and, on the other hand, to the fact that the chip was invented by start-up Tarari in a commercial context which required, for business reasons, a minimum of public disclosure of its design features. It remains, nevertheless, a significant landmark that the XML chip has been sold and continuously improved for the last six years. From the perspective of general computing history, the XML chip is an uncommon example of a successful workload-specific symbolic computing device. With respect to the specific interests of the XML community, the XML chip is a remarkable validation of one of its core founding principles: normalizing on a data format, whatever its imperfections, would enable the developers to, eventually, create tools to process it efficiently.

This paper was prepared for the International Symposium on Processing XML Efficiently: Overcoming Limits on Space, Time, or Bandwidth, a day of discussion among, predominately, software developers working in the area of efficient XML processing. The Symposium is being held as a workshop within Balisage, a conference of specialists in markup theory. Given the interests of the audience this paper does not delve into the design features and principles of the chip itself; rather it presents a dialectic on the motivation for the development of an XML chip in view of related and potentially competing developments in scaling as it is commonly characterized as a manifestation of Moore's Law, parallelization through increasing the number of computing cores on general purpose processors (multicore Von Neumann architecture), and optimization of software.
Performance of XML-based applications: a case-study
Authors: Robinson James A.
Published: August 2009

HighWire Press is the online publishing operation of the Stanford University Libraries, and currently hosts online journals for over 140 separate publishers. HighWire has developed and deployed a new XML-based publishing platform, codenamed H2O, and is in the process of migrating all of its publishers to this new platform.

This paper describes four XML-based systems developed for our new H2O platform, and describes some of the performance characteristics of each. We describe some limitations encountered with these systems, and conclude with thoughts about our experience migrating to an XML-based platform.
Hardware and software trade-offs in the IBM DataPower XML XG4 processor card
Authors: Salz Richard , Achilles Heather , Maze David
Published: August 2009

This presentation will discuss some of the hardware and software trade-offs in the IBM DataPower XML processor, known as the XG4. The XG4 is a PCI card that parses XML, and supports XPath, schema validation, and has a generic post-processing engine. It can return events like SAX, build a tree like a DOM, or switch between modes within a document. It is capable of supporting thousands of sessions simultaneously, and because of its pipeline nature can process more than one character per clock tick. The talk will explain some of the features in the card and its device driver, such as memory usage and zero-copy, synchronization of QName identifiers between card and software, and the programmability.
Memory management in streaming: Buffering, lookahead, or none. Which to choose?
Authors: Zergaoui Mohamed
Published: August 2009

Although the ideal approach to streaming is to process markup events as soon as they are encountered, with no memory needing to be used for storing parts of the input document, this is not always feasible, and in practice it is useful to consider “near-streaming” approaches that involve a limited amount of buffering or lookahead. In the extreme, however, such approaches degenerate until they are indistinguishable from non-streaming processes. This paper attempts a classification of streaming and near-streaming processing methods using different approaches to memory management, and discusses the advantages and disadvantages of each.
Assessment of Gap Junctional Intercellular Communication
Authors: Klaunig James E. , Shi Yuhui
Published: August 2009

Gap junctions are important plasma membrane organelles through which most cells in normal tissues communicate with each other. They exist in two neighboring cells and each cell contributes half of the structure. One gap junction consists of two hexameric connexons that dock with each other to create a channel. Six of the basic subunits referred to as connexins form a connexon. Less than one hundred to several thousand gap junction channels cluster together in the plane of the membrane. The gap junction channels serve as a regulated conduit for the intercellular exchange of small molecules. Maintenance of the integrity of gap junctional intercellular communication (GJIC) is important and required for normal electrical coupling, homeostasis, and embryogenesis. Aberrations of gap junctions have been related to human diseases such as cancer, cardiac arrhythmia, Charcot‐Marie‐tooth disease, and visceroatrial heterotaxia syndrome. This unit describes methods for measuring gap junctional intercellular communication using primary mouse hepatocytes as a model. Focus is only on functional evaluation based on dye coupling. Other methods, such as intracellular calcium waves and dual patch clamp, have been used to measure gap junctional communication, but these are not described in this unit. Curr. Protoc. Toxicol. 41:2.17.1‐2.17.10. © 2009 by John Wiley & Sons, Inc.
Azoreductase in Staphylococcus aureus
Authors: Zou Wen , Cerniglia Carl E. , Chen Huizhong
Published: August 2009

Azoreductase(s) catalyze a NAD(P)H‐dependent reaction in bacteria to metabolize azo dyes to colorless aromatic amines. Azoreductases from bacteria represent a novel family of enzymes with little similarity to other reductases. This unit will describe the current methods for measuring azoreductase from Staphylococcus aureus, which has been suggested to serve as a model strain to study the azo dye degradation by human skin microflora. Curr. Protoc. Toxicol. 41:4.28.1‐4.28.9. © 2009 by John Wiley & Sons, Inc.
Separation of chiral mixtures in real SMB units: The FlexSMB‐LSRE®
Authors: Gomes Pedro Sá , Zabkova Miriam , Zabka Michal , Minceva Mirjana , Rodrigues Alírio. E.
Published: August 2009

In this work, a procedure for the separation of a racemic mixture of guaifenesin onto a chiral stationary phase (Chiralpak AD), by means of Simulated Moving Bed (SMB) technology, is presented in four major steps: (1) search for the suitable stationary and mobile phases; (2) determination of sorption parameters and validation by frontal analysis; (3) modeling and design of the SMB unit; and (4) operation and demonstration. A major emphasis is given to the common deviations that “real” SMB units present when compared with the theoretical apparatus (due to tubing and equipment dead volumes, switching time asymmetries and delays, pumps flow rates variations). These deviations are analyzed before and after the design and construction of the FlexSMB‐LSRE® unit, a new flexible unit, hereby presented. A detailed model that takes into account tubing and equipment dead volumes, as well as switching time asymmetries and delay, was used to study and compare different dead volumes design and compensating strategies. It is shown that all these approaches can be converged into a switching time compensating strategy. This approach served to predict the experimental operating conditions and run a classical SMB experiment, which afterwards was compared with the simulated profiles obtained for the FlexSMB‐LSRE® unit. The result of the separation was guaifenesin enantiomers with purities above 98% and a productivity value of 23 genantiomer/(dm3 CSP day). © 2009 American Institute of Chemical Engineers AIChE J, 2010
Depletion of the neural precursor cell pool by glucocorticoids
Authors: Yu Shuang , Patchev Alexandre V. , Wu Yan , Lu Jie , Holsboer Florian , Zhang Jing‐Zhong , Sousa Nuno , Almeida Osborne F. X.
Published: August 2009

Objective

Glucocorticoids (GCs) are indicated for a number of conditions in obstetrics and perinatal medicine; however, the neurodevelopmental and long‐term neurological consequences of early‐life GC exposure are still largely unknown. Preclinical studies have demonstrated that GCs have a major influence on hippocampal cell turnover by inhibiting neurogenesis and stimulating apoptosis of mature neurons. Here we examined the fate of the limited pool of neural progenitor cells (NPCs) after GC administration during neonatal development; the impact of this treatment on hippocampal structure was also studied.

Methods

Phenotype‐specific genetic and antigenic markers were used to identify cultured NPCs at various developmental stages; the survival of these cells was monitored after exposure to the synthetic glucocorticoid dexamethasone (DEX). In addition, the effects of neonatal DEX treatment on the neurogenic potential of the rat hippocampus were examined by monitoring the incorporation of bromodeoxyuridine and expression of Ki67 antigen at various postnatal ages.

Results

Multipotent nestin‐expressing NPCs and Tα1‐tubulin–expressing immature neurons succumb to GC‐induced apoptosis in primary hippocampal cultures. Neonatal GC treatment results in marked apoptosis among the proliferating population of cells in the dentate gyrus, depletes the NPC pool, and leads to significant and sustained reductions in the volume of the dentate gyrus.

Interpretation

Both NPCs and immature neurons in the hippocampus are sensitive to the proapoptotic actions of GCs. Depletion of the limited NPC pool during early life retards hippocampal growth, thus allowing predictions about the potential neurological and psychiatric consequences of neonatal GC exposure. ANN NEUROL 2010;67:21–30
How beliefs influence the relative magnitude of pleasure and pain
Authors: Mellers Barbara A. , Ritov Ilana
Published: August 2009

Loss aversion is an economic assumption about utility—people value giving up a good more than they value getting it. It also has hedonic meaning—the pain of a loss is greater in magnitude than the pleasure of a comparable gain. But value and pleasure are not necessarily identical. We test the hedonic interpretation of loss aversion in experimental markets. With hedonic forecasts, sellers imagine the pain of losing their endowment, and buyers imagine the pleasure of being endowed. With hedonic experiences, sellers rate the pleasure of having the endowment, and buyers rate the pain of being without it. Contrary to loss aversion, predicted pleasure is greater in magnitude than predicted pain, and experienced pleasure surpasses experienced pain. We show that the relative magnitude of pleasure and pain depends on beliefs about the likelihood of outcomes, as well as utilities. Surprise makes gains more pleasurable and losses more painful. With surprising gains and expected losses, pleasure can surpass pain. But when gains and losses are equally likely (or losses are surprising and gains are expected), the opposite pattern can occur. Finally, within‐group and between‐group prices are significantly correlated with hedonic experiences. Sellers who feel better with their endowments assign higher selling prices, and buyers who feel worse about the absence of endowment assign higher buying prices. Despite the fact that hedonic experiences deviate from loss aversion, these emotions predict the endowment effect. Copyright © 2009 John Wiley & Sons, Ltd.
A Stochastic Regression Model for General Trend Analysis of Longitudinal Continuous Data
Authors: Chao Wei‐Hsiung , Chen Su‐Hua
Published: August 2009

A predictive continuous time model is developed for continuous panel data to assess the effect of time‐varying covariates on the general direction of the movement of a continuous response that fluctuates over time. This is accomplished by reparameterizing the infinitesimal mean of an Ornstein–Uhlenbeck processes in terms of its equilibrium mean and a drift parameter, which assesses the rate that the process reverts to its equilibrium mean. The equilibrium mean is modeled as a linear predictor of covariates. This model can be viewed as a continuous time first‐order autoregressive regression model with time‐varying lag effects of covariates and the response, which is more appropriate for unequally spaced panel data than its discrete time analog. Both maximum likelihood and quasi‐likelihood approaches are considered for estimating the model parameters and their performances are compared through simulation studies. The simpler quasi‐likelihood approach is suggested because it yields an estimator that is of high efficiency relative to the maximum likelihood estimator and it yields a variance estimator that is robust to the diffusion assumption of the model. To illustrate the proposed model, an application to diastolic blood pressure data from a follow‐up study on cardiovascular diseases is presented. Missing observations are handled naturally with this model.
Retroviral vector production under serum deprivation: The role of lipids
Authors: Rodrigues A.F. , Carmo M. , Alves P.M. , Coroadinha A.S.
Published: August 2009

The use of retroviral vectors for gene therapy applications demands high titer preparations and stringent quality standards. However, the manufacturing of these vectors still represents a highly challenging task due to the low productivity of the cell lines and reduced stability of the vector infectivity, particularly under serum‐free conditions. With the objective of understanding the major limitations of retroviral vector production under serum deprivation, a thorough study of viral production kinetics, vector characterization and cell growth and metabolic behavior was conducted, for 293 FLEX 18 and Te Fly Ga 18 producer cell lines using different serum concentrations. The reduction of serum supplementation in the culture medium resulted in pronounced decreases in cell productivity of infectious vector, up to ninefold in 293 FLEX 18 cells and sevenfold in Te Fly Ga 18 cells. Total particles productivity was maintained, as assessed by measuring viral RNA; therefore, the decrease in infectious vector production could be attributed to higher defective particles output. The absence of the serum lipid fraction was found to be the major cause for this decrease in cell viral productivity. The use of delipidated serum confirmed the requirement of serum lipids, particularly cholesterol, as its supplementation not only allowed the total recovery of viral titers as well as additional production increments in both cell lines when comparing with the standard 10% (v/v) FBS supplementation. This work identified lower production ratios of infectious particles/total particles as the main restraint of retroviral vector production under serum deprivation; this is of the utmost importance concerning the clinical efficacy of the viral preparations. Lipids were confirmed as the key serum component correlated with the production of infective retroviral vectors and this knowledge can be used to efficiently design medium supplementation strategies for serum‐free production. Biotechnol. Bioeng. 2009; 104: 1171–1181. © 2009 Wiley Periodicals, Inc.
Evaluation of Optimization Metrics for Continuous Fermentation of Plasmid DNA
Authors: Kelly W. J. , Balguri M. , Asoor A. B. , Piccini J. R. , Muske K. R.
Published: August 2009

An evaluation of cumulative productivity metrics for optimizing the continuous fermentation of plasmid DNA (pDNA) is carried out in this work. DNA plasmids provide a good illustrative example for comparison because of the plasmid instability issues associated with their production. However, the analysis presented in this work can also be applied to other intracellular bioproduct continuous fermentation systems. The productivity metrics considered are cumulative product mass per time, profit, and cost objective functions. These metrics are used to determine the optimal continuous fermentation run time at a given dilution rate, during the dynamic period associated with switching from batch to continuous fermentation. The results of this study indicate that different optimum continuous fermentation run times are predicted based upon the choice of the continuous fermentation operating conditions and optimization metric. In particular, the dilution rate must be larger than the inverse of a characteristic time, that is a function of the initial batch operating and plasmid stability times before continuous operation becomes optimal. Provided that this condition is met, different optimal continuous operation run times are obtained depending on the cumulative productivity metric, or operating objective, that is employed.
On the Electronic Impact of Abnormal C4‐Bonding in N‐Heterocyclic Carbene Complexes
Authors: Heckenroth Marion , Neels Antonia , Garnier Michael G. , Aebi Philipp , Ehlers Andreas W. , Albrecht Martin
Published: August 2009

Sterically similar palladium dicarbene complexes have been synthesized that comprise permethylated dicarbene ligands which bind the metal center either in a normal coordination mode via C2 or abnormally via C4. Due to the strong structural analogy of the complexes, differences in reactivity patterns may be attributed to the distinct electronic impact of normal versus abnormal carbene bonding, while stereoelectronic effects are negligible. Unique reactivity patterns have been identified for the abnormal carbene complexes, specifically upon reaction with Lewis acids and in oxidative addition‐reductive elimination sequences. These reactivities as well as analytical investigations using X‐ray diffraction and X‐ray photoelectron spectroscopy indicate that the C4 bonding mode increases the electron density at the metal center substantially, classifying such C4‐bound carbene ligands amongst the most basic neutral donors known thus far. A direct application of this enhanced electron density at the metal center is demonstrated by the catalytic H2 activation with abnormal carbene complexes under mild conditions, leading to a catalytic process for the hydrogenation of olefins.
RelB/p50 regulates CCL19 production, but fails to promote human DC maturation
Authors: Gasparini Chiara , Foxwell Brian M. J. , Feldmann Marc
Published: August 2009

DC, when fully matured are the APC best able to activate naïve T cells. Recently, we demonstrated using adenoviruses overexpressing IκBα and proteosome inhibitors that NF‐κB is involved in DC activation, but the role of the individual subunits is still not clear. We investigated the role of the NF‐κB subunits RelB and p50 in human DC activation using adenoviral vectors expressing RelB or p50. Nuclear RelB, in the form of RelB/p50, was active only in DC infected with both viruses, this induced the production of the soluble homeostatic chemokine CCL19, but not other homeostatic chemokines, particularly in LPS‐matured DC. However, RelB/p50 did not affect the expression of costimulatory and antigen‐presenting molecules, and increased the allogeneic mixed lymphocyte reaction only in LPS‐matured DC. This enhanced mixed lymphocyte reaction is most likely due to enhanced CCL19 production, which sustains the interaction between mature DC and naïve T cells. In conclusion, we demonstrated that RelB/p50 was active only in DC expressing both RelB and p50, and induced CCL19 production, but not DC maturation.
Si94– Anions in Solution – Structures of the Solvates Rb4Si9·4.75NH3 and [Rb(18‐crown‐6)]Rb3Si9·4NH3, and Chemical Bonding in Si94–
Authors: Joseph Stefanie , Suchentrunk Christof , Kraus Florian , Korber Nikolaus
Published: August 2009

Dissolving the ternary material K6Rb6Si17 together with chelating ligands such as 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane), dibenzo‐18‐crown‐6 (2,3,11,12‐dibenzo‐1,4,7,10,13,16‐hexaoxacyclooctadecane) and [2.2.2]cryptand(4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane)in liquid ammonia yields the solvates Rb4Si9·4.75NH3 and [Rb(18‐crown‐6)]Rb3Si9·4NH3. Single‐crystal X‐ray diffraction analysis reveals the presence of Si94– anions, the existence of which in solution has been a matter of discussion until now. In both compounds, the Si94– cages display slightly distorted monocapped square‐antiprismatic shapes. Additionally, quantum chemical calculations, NBO analysis and ELF (electron localisation function) considerations have been made to gain a deeper insight into the chemical bonding of this Zintl anion. The ELF analysis shows that, whereas the Wade–Mingos–Williams rules obviously apply for the prediction of the molecular shape of the anions, no evidence for three‐centre two‐electron bonding can be found. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Peptization–Hydrothermal Method as a Surfactant‐Free Process toward Nanorod‐Like Anatase TiO2Nanocrystals
Authors: Li Shuang , Li Yaogang , Wang Hongzhi , Fan Wugang , Zhang Qinghong
Published: August 2009

The transparent TiO2sol contained of anatase crystallites was prepared by peptization of anatase TiO2precipitates. With the hydrothermal treatment of TiO2sol at 150 °C, the dispersible and nanorod‐like TiO2nanocrystals were formed by an oriented attachment mechanism. After further hydrothermal treatment of the mixture of nanorod‐like TiO2nanocrystals and the original sol, branched and nanoring‐like nanostructures in the anatase phase were obtained. The as‐prepared TiO2nanocrystals were characterized by X‐ray diffraction, FT‐Raman spectrometry, UV/Vis absorption spectrometry, and transmission electron microscopy (TEM). TEM results indicated that TiO2nanocrystals were nanorod‐like, and more complex microstructures such as the ring‐like and branched TiO2nanostructures with diameters less than 10 nm were formed especially in the two‐step hydrothermal treatment. The adsorption of ruthenium dye (N719) over the nanocrystals with different microstructures was investigated. The adsorption results showed the nanorod‐like anatase TiO2nanocrystals had a high capacity for the ruthenium dye adsorption. The powders were used as electrodes of dye‐sensitized solar cells and showed a conversion efficiency of 5.75 % under 1 sun illumination unit of simulated sunlight. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Double‐Layer Nanogold and Poly(amidoamine) Dendrimer‐ Functionalized PVC Membrane Electrode for Enhanced Electrochemical Immunoassay of Total Prostate Specific Antigen
Authors: Wang Xiu‐Ling , Tao Guan‐Hong , Meng Yuan‐Hua
Published: August 2009

A simple and portable electrochemical immunosensor for the detection of total prostate specific antigen (t‐PSA) in human serum was developed using a double‐layer nanogold particles and dendrimer‐functionalized polyvinyl chloride (PVC) membrane as immunosensing interface. To fabricate such a multifunctional PVC electrode, an o‐phenylenediamine‐doped PVC membrane was initially constructed, then nanogold particles and poly(amidoamine) G4‐dendrimer with a sandwich‐type format were assembled onto the PVC membrane surface, and then t‐PSA antibodies (anti‐PSA) were adsorbed on the nanogold surface. The detection principle of the immunosensor is based on the change in the electric potential before and after the antigen‐antibody interaction. The experimental conditions and the factors influencing the performance of the immunosensor were investigated. Under optimal conditions, the proposed immunosensor exhibits good electrochemical behavior in the dynamic range of 0.5–18 ng/mL relative to t‐PSA concentration with a relative low detection limit of 0.1 ng/mL (S/N=3). The precision, reproducibility, and stability of the immunosensor are acceptable. In addition, 43 serum specimens were assayed by the as‐prepared immunosensor, and consistent results were obtained in comparison with those obtained by the standard enzyme‐linked immunosorbent assay (ELISA). Compared with the conventional ELISAs, the developed immunoassay system was simple and rapid without labeling and separation steps. Importantly, the immobilization and detection methodologies could be extended for the immobilization and detection of other biomarkers.
Peroxidase‐Like Layered Double Hydroxide Nanoflakes for Electrocatalytic Reduction of H2O2
Authors: Wang Yinling , Chen Shuihong , Ni Fang , Gao Feng , Li Maoguo
Published: August 2009

Peroxidase‐like layered double hydroxide (LDH) nanoflakes were synthesized directly and facilely by a one‐pot chemical method, hydrothermal treatment. The as‐prepared LDHs were characterized by transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, Fourier transform IR, and cyclic voltammetry. The functionalized LDHs immobilized on the glassy carbon electrode exhibited a well‐defined pair of redox peaks, excellent electrocatalytic activity toward the reduction of hydrogen peroxide without inhibition of dissolved oxygen and a higher affinity for H2O2, just like the peroxidase. The low apparent Michaelis–Menten constant was only 242 μM. The electrochemical response to H2O2 shows a linear range of 12–254 μM with the calculated detection limit of 2.3 μM at a signal‐to‐noise ratio of 3. Furthermore, compared with most metal hexacyanoferrates, the peroxidase‐like LDHs are very stable in neutral and alkaline solution. The electrochemical and electrocatalytic behavior of the functionalized LDHs indicate that they may be useful to explore man‐made mimics of enzyme in electrochemical biosensors.
Structured Nucleic Acid Probes for Electrochemical Devices
Authors: Miranda‐Castro Rebeca , de‐los‐Santos‐Álvarez Noemí , Lobo‐Castañón María Jesús , Miranda‐Ordieres Arturo J. , Tuñón‐Blanco Paulino
Published: August 2009

The use of nucleic acid with a specific sequence and a highly ordered secondary structure such as hairpins, quadruplexes and pseudoknots as biological recognition elements and switches in biosensors is rapidly increasing because of their improved features (e.g. selectivity) when compared with the traditional linear probes. Owing to the novelty, a critical outlook of their characteristics and a compilation of the latest advances are lacking. This article describes the potential of those nucleic acids probes whose molecular recognition ability relies on a conformational change (e.g. folding/unfolding mechanism) in electrochemical sensing. It provides an overview of the toolbox of assays using these probes for genosensors and aptasensors, highlighting its performance characteristics and the prospects and challenges for biosensor design.
On‐column labeling technique and chiral ligand‐exchange CE with zinc(II)‐L‐arginine complex as a chiral selector for assay of dansylated D,L‐amino acids
Authors: Qi Li , Yang Gengliang
Published: August 2009

A novel on‐column labeling method of amino acid (AA) enantiomers by using dansyl chloride (Dns‐Cl) has been explored combined with chiral ligand‐exchange CE (CLE‐CE) technique and UV detection. Efficient labeling was achieved by sequential injection of buffer, Dns‐Cl, AA enantiomers, Dns‐Cl and buffer at 0.2 psi for 10.0, 3.0, 24.0, 3.0, and 10.0 s, respectively. After injection, the sandwich sections were allowed to react at room temperature for 35.0 min. With this procedure, successful on‐column labeling and CLE‐CE separation of 17 pairs AA enantiomers have been achieved with a buffer of 100.0 mM boric acid, 5.0 mM ammonium acetate, 3.0 mM ZnSO4 and 6.0 mM L‐Arg at pH 8.4, giving nine pairs fully enantioresolved with resolution in between 2.0 and 5.1. CLE‐CE of some individual and mixed pairs was also demonstrated, much the same as using pre‐column labeling. As validated by both artificially prepared solutions and serum samples, this new method was shown to be applicable to the quantitative analysis, with a linear range between 14.0 μM and 3.7 mM, correlation coefficient above 0.99 and recovery in between 90.4% and 111.7%. It was also demonstrated that the migration time‐temperature based curve allows for temperature determination in CE by using this new method.
Enantiomeric separation of chiral dipeptides by CE‐ESI‐MS employing a partial filling technique with chiral crown ether
Authors: Xia Shifei , Zhang Lan , Lu Minghua , Qiu Bin , Chi Yuwu , Chen Guonan
Published: August 2009

Enantiomer of chiral dipeptides were separated by CE‐ESI‐MS in a bare fused‐silica capillary using (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid (18C6H4) as the chiral selector. As 18C6H4 is a kind of nonvolatile chiral selector, in order to prevent from 18C6H4 into the ion‐source of CE‐ESI‐MS, a partial filling technique was employed in this study. Some dipeptides with one chiral center or two chiral centers, such as DL‐Leu‐DL‐Leu, D‐Ala‐D‐Ala and L‐Ala‐L‐Ala, Gly‐D‐Phe and Gly‐L‐Phe were used to evaluate this CE‐ESI‐MS system. Optimized conditions were achivevd with 2.0 mol/L acetic acid (pH 2.15) as the running electrolyte, 5 mM 18C6H4 in 3.0 mol/L acetic acid (pH 2.00) was injected hydrodynamically (50 mbar for 960 s) before sample injection. In total 7.5 mM acetic acid in 80% v/v methanol–water was used as the sheath liquid, and 20 kV applied voltage was used. Under the optimum conditions, these dipeptides were separated and detected. LODs (defined as S/N=3) of this method were 0.20, 0.10, 0.05 and 0.10 μmol/L for D‐Ala‐D‐Ala, L‐Ala‐L‐Ala, DL‐Leu‐DL‐Leu, Gly‐L‐Phe and Gly‐D‐Phe, respectively. The RSDs (n=7) of the method were 0.68–2.08% for migration times and 2.32–5.24% for peak areas. The proposed method was also successfully applied to the enantioselective analysis of these dipeptides in the spiked serum samples with satisfactory results.
Enantioseparation of amino acids, α‐hydroxy acids, and dipeptides by ligand‐exchange CEC using silica‐based chiral stationary phases
Authors: Pittler Elfriede , Grawatsch Nina , Paul Dörte , Gübitz Gerald , Schmid Martin G.
Published: August 2009

This work deals with the application of silica‐based ligand‐exchange chiral stationary phases (CSPs) for the enantioseparation of underivatised amino acids, α‐hydroxy acids, and dipeptides with packed CEC. Two different possibilities of preparing silica‐based CSPs are presented. One phase contains L‐4‐hydroxyproline chemically bonded via a spacer to 3 μm silica material. The other approach makes use of N‐decyl‐L‐4‐hydroxyproline dynamically coated on a reversed‐phase packed capillary. Dynamical coating of reversed‐phase material represents a simple alternative to prepare CSP. A comparison of the chemically bonded phase with the dynamically coated CSP by means of resolution of complex‐forming analytes is presented. The chemically bonded phase was found to be superior to the dynamically coated phase in terms of resolution of amino acids and dipeptides. However, the dynamically coated CSP was found to be especially suitable for the separation of α‐hydroxy acids. Both techniques are applicable for enantiomer purity tests.
Adsorption of trypsin on commercial silica gel
Authors: Gómez José M. , Romero Ma. Dolores , Hodaifa Gassan , de la Parra Elena
Published: August 2009

The immobilization of trypsin onto various commercial silica gels was studied. Silica gels were used directly and characterized by mercuric porosimetry. Agitation rates (100–740 rpm) and particles size (35–75 to 250–500 μm) of silica gels did not affect the trypsin immobilization capacity. The pore size (3 to 15 nm) is a limiting factor of the trypsin adsorption onto the mesopores structure of silica gels. The adsorption of trypsin was determined as a function of their initial concentration and multilayer formed at high trypsin concentration.
Optimal seismic design of moment‐resisting steel frames with hysteretic passive devices
Authors: Apostolakis G. , Dargush G. F.
Published: August 2009

The effectiveness of hysteretic passive devices to protect and mitigate the response of a structure under seismic loading is well established by both analytical and experimental research. Nevertheless, a systematic and well‐established methodology for the topological distribution and size of these devices in order to achieve a desired structural response performance does not exist. In this paper, a computational framework is proposed for the optimal distribution and design of yielding metallic buckling restrained braces (BRB) and/or friction dampers within steel moment‐resisting frames (MRF) for a given seismic environment. A Genetic Algorithm (GA) is used to solve the resulting discrete optimization problem. Specific examples involving two three‐story, four‐bay steel MRFs and a six‐story, three‐bay steel MRF retrofitted with yielding and/or friction braces are considered. The seismic environment consists of four synthetic ground motions representative of the west coast of the United States with 5% probability of exceedance in 50 years. Non‐linear time‐history analyses are employed to evaluate the potential designs. As a result of the evolutionary process, the optimal placement, strength and size of the dampers are obtained throughout the height of the steel MRF. Furthermore, the developed computational approach for seismic design based upon GAs provides an attractive procedure for design of MRFs with hysteretic passive dampers. Copyright © 2009 John Wiley & Sons, Ltd.
Comparative leaf epidermis investigation in species of genus Crataegus L. (Rosaceae) from Bulgaria
Authors: Ganeva Ts. , Uzunova Kr. , Koleva D.
Published: August 2009

The leaf epidermis structure of six Crataegus species from Bulgaria has been studied by light and scanning electron microscopy. Cyclocytic stomatal type, different types of simple single trichomes, cuticle ornamentation and waxes are determined. The results allow clear delimitation and identification of the species. Some conjectures about the relationships on inter‐ and intrageneric level and references of epidermal structure with adaptation to various ecological conditions are discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Potentilla L. (Rosaceae) in the former USSR; second part: comments Notes on Potentilla XXIV
Authors: Soják J.
Published: August 2009

This article contains comments on 88 species of Potentilla and three allied genera that grow in the territory of the former USSR. They deal mainly with taxonomic or nomenclatural issues, sometimes accompanied by notes on distribution. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The validity of Ochetophila Poepp. ex Endl. (Rhamnaceae: Colletieae)
Authors: Medan D. , Kellermann J. , Aagesen L. , Hilger H. H.
Published: August 2009

It is shown that doubts raised recently (Feddes Rep. 119: 622–624, 2008) about the validity of Ochetophila Poepp. ex Endl. as distinct from Discaria Hook. are based on unsound arguments. The distinctness of Ochetophila rests upon a solid cladistic analysis of the tribe Colletieae (Rhamnaceae) and adequately reflects the current knowledge of this group. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of the staff MFF in distributing NHS funding: taking account of differences in local labour market conditions
Authors: Elliott Robert , Ma Ada , Sutton Matt , Skatun Diane , Rice Nigel , Morris Stephen , McConnachie Alex
Published: August 2009

The National Health Service (NHS) in England distributes substantial funds to health‐care providers in different geographical areas to pay for the health care required by the populations they serve. The formulae that determine this distribution reflect populations' health needs and local differences in the prices of inputs. Labour is the most important input and area differences in the price of labour are measured by the Staff Market Forces Factor (MFF). This Staff MFF has been the subject of much debate. Though the Staff MFF has operated for almost 30 years this is the first academic paper to evaluate and test the theory and method that underpin the MFF. The theory underpinning the Staff MFF is the General Labour Market method. The analysis reported here reveals empirical support for this theory in the case of nursing staff employed by NHS hospitals, but fails to identify similar support for its application to medical staff. The paper demonstrates the extent of spatial variation in private sector and NHS wages, considers the choice of comparators and spatial geography, incorporates vacancy modelling and illustrates the effect of spatial smoothing. Copyright © 2009 John Wiley & Sons, Ltd.
Drug development costs when financial risk is measured using the Fama–French three‐factor model
Authors: Vernon John A. , Golec Joseph H. , Dimasi Joseph A.
Published: August 2009

In a widely cited article, DiMasi, Hansen, and Grabowski (2003) estimate the average pre‐tax cost of bringing a new molecular entity to market. Their base case estimate, excluding post‐marketing studies, was $802 million (in $US 2000). Strikingly, almost half of this cost (or $399 million) is the cost of capital (COC) used to fund clinical development expenses to the point of FDA marketing approval. The authors used an 11% real COC computed using the capital asset pricing model (CAPM). But the CAPM is a single factor risk model, and multi‐factor risk models are the current state of the art in finance. Using the Fama–French three factor model we find that the cost of drug development to be higher than the earlier estimate. Copyright © 2009 John Wiley & Sons, Ltd.