bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge Sourcing Beyond Buzz and Pipelines: Evidence from the Vienna Software Sector
Authors: Trippl Michaela , Tödtling Franz , Lengauer Lukas
Published: August 2010

abstract

This article examines the nature and geography of knowledge linkages in the Vienna software cluster. Empirical studies on the software sector have provided contradictory evidence of the relative importance of different sources of knowledge, the spatial dimension of exchanges of knowledge, and the relevance of different channels for the transmission of knowledge. Recent conceptual work on the geography of knowledge linkages has highlighted that the innovative dynamics of clusters rests on both local and global knowledge flows, that is, the combination of “local buzz” and “global pipelines.” However, the buzz‐and‐pipelines approach fails to provide a precise understanding of the mechanisms by which actors in a cluster gain access to knowledge at different spatial scales. This article goes beyond the buzz‐and‐pipelines concept and suggests a differentiated typology of knowledge linkages, distinguishing among market relations, formal networks, spillovers, and informal networks. Drawing on a survey of firms and face‐to‐face interviews with representatives of companies, we demonstrate that in the Vienna software industry, knowledge flows are informal. We found that spillovers and informal networks are highly significant at all spatial scales and are complemented by formalized research‐and‐development partnerships at the local and national levels. We also show that the character of knowledge linkages is dependent on the nature of innovation. The more radical the innovation, the larger the variety of sources of knowledge and the stronger the diversity of the mechanisms for transferring knowledge.
Geographies of Financialization in Disarray: The Dutch Case in Comparative Perspective
Authors: Engelen Ewald , Konings Martijn , Fernandez Rodrigo
Published: August 2010

abstract

The securitization crisis that started in mid‐2007 has demonstrated that we are indeed living in a “global financial village” and are all subject to the vagaries of financialization. Nevertheless, the fallout from the credit crisis has not been homogeneous across space. That some localities were hit harder than others suggests that there are distinct geographies of financialization. Combining insights from the “varieties of capitalism” literature with those from the literature on “financialization studies,” the article offers a first take on what may explain these different geographies on the basis of an informal comparison of the trajectories of financialization and their political repercussions in the United States, Germany, and the Netherlands. The article ends with some reflections on how economic geography could be enriched by combining comparative studies on institutionalism and financialization, while its distinct research focus—detailed spatial analysis endowed with a well‐developed sensitivity for geographic variegation—may help overcome the methodological nationalism of much comparative institutionalism.
Osteosarcoma of the proximal radius in a donkey
Authors: Kilcoyne I. , Wilson M. , Terzo E. , David F.
Published: August 2010

A mature donkey was presented for evaluation of a forelimb lameness and presence of a large mass on the left forelimb distal to the elbow joint. Clinical examination, radiographs and cytological examination of ultrasound‐guided fine needle aspirates of the mass led to a presumptive diagnosis of osteosarcoma. The donkey was subsequently subjected to euthanasia. Post mortem examination confirmed the diagnosis of osteosarcoma in the proximal radius with expansion of the mass through the ulnar cortex and metastases to liver and regional lymph nodes, areas of metastasis previously unreported in the equine literature.
Mechanical and Thermal Stresses in Clamped, Brazed, and Bonded Carbide Tools
Authors: Younis M. A.
Published: August 2010

A model based on the finite element method is presented for determining of thermal and mechanical stresses in a carbide insert due to heat and cutting forces induced during metal cutting with a brazed, clamped, and bonded carbide insert. Analysis revealed a high temperature gradient in the brazed insert, thus causing high thermal stresses. For the bonded insert a low temperature gradient but high temperatures were found, leading to possible tool edge chipping and a significant reduction of the bond layer strength. Finally local maxima of tensile and compressive stresses were identified on the rake face just after the chip had lost contact with the tool face. The estimated tensile stresses were close to the transverse rupture strength of sintered carbide. Shear stresses were at a maximum close to the tool edge at levels nearly equal to the shear flow strength of carbides. High compressive stresses can produce chipping at the tool tip.
Prediction of Cutting Forces and Tool Breakage in Milling from Feed Drive Current Measurements
Authors: Altintas Y.
Published: August 2010

This paper describes the use of current drawn by feed drive motors for milling process monitoring. A model of a vertical milling machine feed drive control system is used to analyze cutting force measurements from the drive motors. The current and voltage limits in the amplifier, and the friction in the feed drive assembly are included in the analysis. The viability of using armature current as a cutting force measurement sensor is discussed. The pulsating milling forces are predicted from the current measurements at tooth passing frequencies which are within the bandwidth of the servo. It is shown that tool failure in milling can be detected within one spindle revolution by adaptively filtering the average current signals at tooth passing periods. The residual terms of a first order auto-regressive time series filter is found to be sensitive to the tool failure event. The tool breakage algorithm is independent of cutting conditions and the friction in the drive system.
Tool Status Recording and Its Use in Probabilistic Optimization
Authors: Zhou Chen , Wysk R. A.
Published: August 2010

In batch production, recording the status of cutting tools and making decisions based on current tool status are important issues. In flexible manufacturing systems, there are normally many tools installed on machining centers. These tools are often used on different operations due to frequent change over in the system. The tool usage recording and the decision making based on tool status in this environment are crucial. The commonly adopted time measure is not sufficient because tool life is influenced by many factors. A tool status measure (tool wear index) is introduced in this paper. The index is affected by both direct cutting time and the type of cutting involved. Tooling cost recovery and probabilistic models are also developed to identify the cutting speed and replacement time based on tool wear index for minimum unit cost. The objective is to minimize the unit direct machining cost due to tooling, machining time, and in-process tool failure penalty.
The Optimization of Machining Operations Based on a Combined Criterion, Part 1: The Use of Combined Objectives in Single-Pass Operations
Authors: Agapiou J. S.
Published: August 2010

The problem of determining the optimum machining conditions for single-pass and multipass operations has been investigated. An objective function incorporating a combination of the minimum production cost and minimum production time requirements is considered for optimization. The two criteria of production cost and production time are prioritized through their weight coefficients. A constant multiplier is used to normalize the objective function. The optimum machining conditions are then determined by the Nelder-Mead simplex method. Physical constraints regarding the cutting parameters are also considered. The structure of the objective function is analyzed and the procedure to construct it is discussed. The superiority of the combined objective function over the earlier proposed single criteron objective functions, using the production cost, or production time, or maximum rate of profit, is illustrated. A sensitivity analysis for the weight coefficients and the constant multiplier of the objective function are discussed via numerical examples.
The Importance of the Application Sequence of Clamping Forces on Workpiece Accuracy
Authors: Cogun C.
Published: August 2010

The effect of the application sequence of clamping forces on the mounting accuracy of a workpiece is investigated mathematically and experimentally. It is shown that clamping sequence causes a change in workpiece position on the machine tool. It is established that selection of a rational sequence of clamping force is important for the control of workpiece displacement under clamping forces.
Pharmacy Benefit Managers, Pharmacies, and Pharmacogenomic Testing: Prescription for Progress?
Authors: Topol Eric J.
Published: August 2010

As prescription drug costs rise, companies such as Medco are moving to promote pharmacogenomics-based testing to inform therapeutic choices.
Fatty Acid Oxidation and Malonyl-CoA Decarboxylase in the Vascular Remodeling of Pulmonary Hypertension
Authors: Sutendra Gopinath , Bonnet Sebastien , Rochefort Gael , Haromy Alois , Folmes Karalyn D. , Lopaschuk Gary D. , Dyck Jason R. B. , Michelakis Evangelos D.
Published: August 2010

The overgrowth of vascular cells that causes pulmonary hypertension can be prevented in mice by inhibiting a metabolic shift toward glycolysis.
Making Research Reproducible
Authors: Carlson Nichole
Published: August 2010

Reproducible research requires that the “hows” and “whys” of statistical methods be made widely available.
Genomic and Stem-Cell Technologies Collide
Authors: Damani Samir
Published: August 2010

Pluripotent stem cells are used to model Long-QT syndromes and explain the functional effects of a prominent mutation in the
KCNQ1
gene.
Association of metabolic syndrome and IgA nephropathy
Authors: Wang Liping , Zhang Yong , Chen Shanyuan , Chen Jian , Zhuang Yongze , Chen Jinhua
Published: August 2010

Background

The disorders associated with metabolic syndrome (MS) can lead to renal disease. IgA nephropathy is the most common form of glomerulonephritis, and many patients with this disorder progress to renal failure.

Aims

To identify the effect of MS on IgA nephropathy by retrospectively comparing patients who had IgA nephropathy and MS with those who had IgA nephropathy alone.

Methods

30 patients with MS and IgA nephropathy (MS group), and 30 matched controls with IgA nephropathy alone (non-MS group) were enrolled. IgA nephropathy was diagnosed by renal biopsy; activity and severity was graded by two classification systems. MS was diagnosed by criteria of the Diabetes Society of the Chinese Medical Association.

Results

Simple and multiple linear regression models (which adjusted for age, gender and body surface area) showed that only hypertension significantly affected serum creatinine, an indicator of the clinical severity of renal disease. Simple and multiple linear regression models (which adjusted for age, gender and body surface area) also showed that hypertensive patients had higher Katafuchi scores, an indicator of the pathological severity of renal disease.

Conclusion

Among the disorders associated with MS, hypertension is the most important factor for renal disease.
Different patterns of BK and JC polyomavirus reactivation following renal transplantation
Authors: Saundh Baljit K , Tibble Stephen , Baker Richard , Sasnauskas Kestutis , Harris Mark , Hale Antony
Published: August 2010

Aim

Reactivation of latent BK polyomavirus (BKV) infection is relatively common following renal transplantation and BKV-associated nephropathy has emerged as a significant complication. JC polyomavirus (JCV) reactivation is less well studied. The aim of the study was to determine reactivation patterns for these polyomaviruses in renal transplant recipients using an in-house quantitative real-time multiplex PCR assay and IgG serological assays using recombinant BK and JC virus-like particles.

Methods

Retrospective analysis of urine and plasma samples collected from 30 renal transplant patients from February 2004 to May 2005 at Leeds Teaching Hospitals NHS Trust. Samples were collected at 5 days and thereafter at 1, 3, 6 and 12 months post-transplantation.

Results

Eight patients (26.7%) were positive for BK viruria; three of these patients submitted plasma samples and two had BK viraemia. Five patients (16.7%) were positive for JC viruria. A corresponding rise in BKV and JCV antibody titres was seen in association with high levels of viruria.

Conclusions

Different patterns of reactivation were observed: BK viruria was detected after 3–6 months, and JC viruria was observed as early as 5 days post-transplantation. One patient had biopsy-proven BKV nephropathy. No dual infections were seen. In order to ensure better graft survival, early diagnosis of these polyomaviruses is desirable.
Expression of high-molecular-weight cytokeratin (34βE12) is an independent predictor of disease-free survival in patients with triple-negative tumours of the breast
Authors: Mehta Rutika , Jain Rohit K , Sneige Nour , Badve Sunil , Resetkova Erika
Published: August 2010

One-fifth of breast cancers have the triple-negative phenotype; a good prognostic marker has yet not been described for these tumours. Tumour microarrays from 58 triple-negative patients treated with surgery followed by chemotherapy were analysed for expression of cytokeratin 5/6 (CK5/6), epidermal growth factor receptor (EGFR), vimentin, p63 and cytokeratin 34βE12. The mean patient age was 59.2 years with a follow-up from 39 to 168 months. Clinicopathological variables and survival data were correlated with biomarker expression. The frequency of expression of cytokeratin 5/6, EGFR, vimentin, p63 and 34βE12 was 33%, 65%, 50%, 19% and 85%, respectively. Each of 34βE12, p63, EGFR and T stage significantly correlated with both disease-free survival and overall survival. T stage and 34βE12 were independent predictors of overall survival in a multivariate analysis. Expression of 34βE12 predicts disease-free and overall survival in patients with triple-negative tumours. Additional studies are planned to confirm these initial findings.
Oropharyngeal lesions and cervical lymphadenopathy: syphilis is a differential diagnosis that is still relevant
Authors: Ikenberg Kristian , Springer Erik , Bräuninger Wolfgang , Kerl Katrin , Mihic Daniela , Schmid Simone , Schmitt Anja , Yeginsoy Sibel , Bode Beata , Weber Achim
Published: August 2010

Background

Syphilis (lues), a chronic infectious disease caused byTreponema pallidum, has been increasing in incidence during the last few years. Therefore, while clinically it is often not suspected, syphilis is increasingly becoming a differential diagnosis in routine pathology.

Aim

To report our experience with five cases of cervical lymphadenopathy and/or oropharyngeal lesions, clinically thought to be lymphomas, lymph node metastases or carcinoma, in which we made the mostly clinically unsuspected diagnosis of syphilis.

Methods

Fine needle aspiration of enlarged cervical lymph nodes was evaluated by cytology and flow cytometry (fluorescence-activated cell sorting analysis), and biopsies were examined by using histology. In addition, all materials were also subjected to immunostaining, silver staining and molecular (PCR) testing.

Results

Fine needle aspiration cytology revealed follicular hyperplasia in two cases and granulomatous lymphadenitis in one case. In three patients, concomitant biopsy of co-existing oropharyngeal lesions revealed histological findings compatible with syphilis.T pallidumwas detected in all cytological and histological samples by immunohistochemistry/immunocytochemistry and PCR. Subsequently, a diagnosis of syphilis was confirmed clinically and by serology.

Conclusions

Syphilitic lymphadenitis is still a relevant differential diagnosis of cervical lymphadenopathy, and it is clinically often not suspected. Co-exisiting oropharyngeal lesions should alert the physician to this differential diagnosis; and lesions with compatible morphology should be tested with immunohistochemistry and immunocytochemistry and/or molecular analysis to confirm the diagnosis of syphilis.
E355G mutation appearing in a patient with e19a2 chronic myeloid leukaemia resistant to imatinib
Authors: Bennour Ayda , Beaufils Nathalie , Sennana Halima , Meddeb Balkis , Saad Ali , Gabert Jean
Published: August 2010

The development of imatinib is a milestone in the treatment of chronic myeloid leukaemia (CML), and its therapeutic effect has been extensively investigated in patients with CML who carry M-bcrand m-bcrBCR–ABLfusion transcripts. However, knowledge about its therapeutic effect on patients with CML who have the rareBCR–ABLfusion transcript e19a2 (μ-bcr) remains sparse. This report describes a patient with Philadelphia-positive chronic myeloid leukaemia with e19a2 rearrangement, in whom E355G mutation had been acquired. The patient was resistant to imatinib treatment based on conventional cytogenetic and fluorescence in situ hybridisation analysis.
Expression of intestinal MUC17 membrane-bound mucin in inflammatory and neoplastic diseases of the colon
Authors: Senapati Shantibhusan , Ho Samuel B , Sharma Poonam , Das Srustidhar , Chakraborty Subhankar , Kaur Sukhwinder , Niehans Gloria , Batra Surinder K
Published: August 2010

Aim

To determine the cellular location and expression of MUC17 mucin in specimens of normal, inflamed and neoplastic colon.

Methods

Immunohistochemical analysis of human surgical resection specimens (n=106) was performed with a specific antibody to the MUC17 apomucin protein. A semi-quantitative scoring system was used to measure MUC17 expression. In various colon cancer cell lines, the MUC17 expression was examined by immunoblot analysis and normal RT-PCR.

Results

MUC17 was highly expressed on the surface epithelium and crypts of colonic mucosa. In contrast, the expression of MUC17 was significantly decreased in colonic mucosa of chronic ulcerative colitis (p<0.0001) and ischaemic colitis (p=0.003). Similarly, MUC17 expression was decreased in hyperplastic polyps (p=0.0003), tubular and tubulovillous adenomas (p<0.0001) and colon cancers (p<0.0001). Furthermore, of eight different colon cancer cell lines, MUC17 expression was only detected in LS174T and LS180 cells.

Conclusion

Results indicate that the potential protective effects of this membrane-bound mucin are primarily or secondarily diminished in inflammatory and neoplastic conditions. Further research is needed to determine the specific role of MUC17 in the pathogenesis of these conditions.
SEMISTABILITY AND NUMERICALLY EFFECTIVENESS IN POSITIVE CHARACTERISTIC
Authors: BISWAS INDRANIL , HOLLA YOGISH I.
Published: August 2010

Let G be a connected reductive linear algebraic group defined over an algebraically closed field k of positive characteristic. Let Z(G) ⊂ G be the center, and [Formula: see text], where each Gi is simple with trivial center. For i ∈ [1, m], let ρi : G → Gi be the natural projection. Fix a proper parabolic subgroup P of G such that for each i ∈ [1, m], the image ρi(G) ⊂ Gi is a proper parabolic subgroup. Fix a strictly anti-dominant character χ of P such that χ is trivial on Z(G). Let M be a smooth projective variety, defined over k, equipped with a very ample line bundle ξ. Let EG → M be a principal G-bundle. We prove that the following six statements are equivalent:

(1) The line bundle EG(χ) → EG/P associated to the principal P-bundle EG → EG/P for the character χ is numerically effective.

(2) The sequence of principal G-bundles [Formula: see text] is bounded, where FM is the absolute Frobenius morphism of M.

(3) The principal G-bundle EG is strongly semistable with respect to ξ, and c2( ad (EG)) is numerically equivalent to zero.

(4) The principal G-bundle EG is strongly semistable with respect to ξ, and [c2( ad (EG))c1(ξ)d-2] = 0.

(5) The adjoint vector bundle ad (EG) is numerically effective.

(6) For every pair of the form (Y,ψ), where Y is an irreducible smooth projective curve and ψ : Y → M is a morphism, the principal G-bundle ψ*EG → Y is semistable.
SYNTHESIS AND STRUCTURE OF PURE AND Mn-DOPED ZINC OXIDE NANOPOWDERS
Authors: ABRISHAMI M. EBRAHIMIZADEH , HOSSEINI S. M. , KAKHKI E. ATTARAN , KOMPANY A. , GHASEMIFARD M.
Published: August 2010

Zn 1-x Mn x O (x = 0, 0.02, 0.06, 0.10, 0.15) nanopowders were synthesized by the sol–gel technique calcinated at low temperatures. By decreasing the grain size in ZnO , the solubility of magnetic impurity has been increased and no detectable secondary phases were observed even in the high Mn -doping samples. The phase formation, size and morphology of nanoparticles were investigated using X-ray diffraction and SEM observations. The samples were ferromagnetic and the Curie point was found in the range 150–170 K for Zn0.94Mn0.06O and 135–150 K for Zn0.98Mn0.02O . Optical characterization and the effect of doping were carried out by means of Fourier transform infrared (FTIR) spectroscopy. Kramers–Kronig analysis was employed to evaluate the optical constants of pure ZnO and ZnO:Mn nanopowders.
DEVELOPMENT IN MICROREACTOR TECHNOLOGY FOR NANOPARTICLE SYNTHESIS
Authors: SINGH AKANKSHA , MALEK CHANTAL KHAN , KULKARNI SULABHA K.
Published: August 2010

Microreactor technology is a new concept of chemical synthesis for nanoparticle production. The "state of the art" in microreactor fabrication and its application to the synthesis of nanoparticles is reviewed. The microfluidic concepts, the materials and technologies for microreactor manufacture, with particular emphasis on polymers and microreplication techniques, and their application to the synthesis of various nanomaterials in microreactors are presented. The unique synthesis properties of various nanoparticles using a microfluidic process as well as broader impact in term of nanomaterials engineering, i.e., selectivity and monodispersity, reduced amount of chemicals, fast reaction, minimum cost, a better control of the process, minimum waste and reduced amounts of reaction byproducts and improved safety, are discussed in comparison with the traditional wet-chemical batch synthesis approach.
Semantics of fractional permissions with nesting
Authors: Boyland John Tang
Published: August 2010

Permissions specify mutable state that can be accessed by a program. Fractions distinguish write access (1) from read access (any smaller fraction). Nesting can model object invariants and ownership. Fractional permissions provides a foundation the meaning of many of access-based annotations: uniqueness, read-only, immutability, method effects, guarded state, etc. The semantics of fractional permissions with nesting is given in terms of “fractional heaps.” We show that the fraction law Π ≡ 1/2 Π + 1/2 Π permits sound reasoning and that nesting can be carried out safely using only local reasoning.
WYSINWYX
Authors: Balakrishnan Gogul , Reps Thomas
Published: August 2010

Over the last seven years, we have developed static-analysis methods to recover a good approximation to the variables and dynamically allocated memory objects of a stripped executable, and to track the flow of values through them. The article presents the algorithms that we developed, explains how they are used to recover Intermediate Representations (IRs) from executables that are similar to the IRs that would be available if one started from source code, and describes their application in the context of program understanding and automated bug hunting.

Unlike algorithms for analyzing executables that existed prior to our work, the ones presented in this article provide useful information about memory accesses, even in the absence of debugging information. The ideas described in the article are incorporated in a tool for analyzing Intel x86 executables, called CodeSurfer/x86. CodeSurfer/x86 builds a system dependence graph for the program, and provides a GUI for exploring the graph by (i) navigating its edges, and (ii) invoking operations, such as forward slicing, backward slicing, and chopping, to discover how parts of the program can impact other parts.

To assess the usefulness of the IRs recovered by CodeSurfer/x86 in the context of automated bug hunting, we built a tool on top of CodeSurfer/x86, called Device-Driver Analyzer for x86 (DDA/x86), which analyzes device-driver executables for bugs. Without the benefit of either source code or symbol-table/debugging information, DDA/x86 was able to find known bugs (that had been discovered previously by source-code analysis tools), along with useful error traces, while having a low false-positive rate. DDA/x86 is the first known application of program analysis/verification techniques to industrial executables.
Interview with Jessy Keiser
Authors: Gualtieri Lisa
Published: August 2010

Jessy Keiser is an organization development professional whose career path lead her to teach for the University of Phoenix, the for-profit learning institution best known for its online presence and open-enrollment policy. In this interview, she spoke about how she came to teach at Phoenix, what kind of training and assessment was required, and some of the pros and cons of its system.
Persuasion: Empirical Evidence
Authors: DellaVigna Stefano , Gentzkow Matthew
Published: August 2010

We provide a selective survey of empirical evidence on the effects as well as the drivers of persuasive communication. We consider persuasion directed at consumers, voters, donors, and investors. We organize our review around four questions. First, to what extent does persuasion affect the behavior of each of these groups? Second, what models best capture the response to persuasive communication? Third, what are persuaders' incentives, and what limits their ability to distort communications? Finally, what evidence exists on the way persuasion affects equilibrium outcomes in economics and politics?
Currency Unions in Prospect and Retrospect
Authors: Silva J.M.C. Santos , Tenreyro Silvana
Published: August 2010

We critically review the recent literature on currency unions and discuss the methodological challenges posed by the empirical assessment of their costs and benefits. In the process, we provide evidence on the economic effects of the euro. In particular, and in contrast with estimates of the trade effect of other currency unions, we find that the euro's impact on trade has been close to zero. After reviewing the costs and benefits of joining a currency union, we conclude with some open questions on normative and positive aspects of the theory of currency unions, emphasizing the need for a unified welfare-based framework to weigh their costs and gains.
Collateral Actions of Premotor Interneurons on Ventral Spinocerebellar Tract Neurons in the Cat
Authors: Jankowska E. , Krutki P. , Hammar I.
Published: August 2010

Strong evidence that premotor interneurons provide ventral spinocerebellar tract (VSCT) neurons with feedback information on their actions on motoneurons was previously found for Ia inhibitory interneurons and Renshaw cells, while indications for similar actions of other premotor interneurons were weaker and indirect. Therefore the aim of the present study was to reexamine this possibility with respect to interneurons relaying actions of group Ib afferents from tendon organs and group II afferents from muscle spindles. In all, 133 VSCT neurons in the L3–L5 segments (including 41 spinal border neurons) were recorded from intracellularly in deeply anesthetized cats to verify that stimuli applied in motor nuclei evoked monosynaptic inhibitory postsynaptic potentials (IPSPs) attributable to stimulation of axon collaterals of premotor interneurons. IPSPs were found in over two thirds of the investigated neurons. When intraspinal stimuli were preceded by stimuli applied to a muscle nerve at critical intervals, IPSPs evoked from motor nuclei were considerably reduced, indicating a collision of nerve volleys in axons of interneurons activated by group I and group II afferents. In individual VSCT neurons monosynaptic IPSPs were evoked from both biceps–semitendinosus and gastrocnemius–soleus motor nuclei, in parallel with disynaptic IPSPs from group Ib and group II as well as group Ia afferents. These observations indicate that individual VSCT neurons may monitor the degree of inhibition of both flexor and extensor motoneurons by premotor interneurons in inhibitory pathways from group Ib and group II afferents to motoneurons. They may thus be providing the cerebellum with feedback information on actions of these premotor interneurons on motoneurons.
Evidence for Opponent-Channel Coding of Interaural Time Differences in Human Auditory Cortex
Authors: Magezi David A. , Krumbholz Katrin
Published: August 2010

In humans, horizontal sound localization of low-frequency sounds is mainly based on interaural time differences (ITDs). Traditionally, it was assumed that ITDs are converted into a topographic (or rate-place) code, supported by an array of neurons with parametric tuning to ITDs within the behaviorally relevant range. Although this topographic model has been confirmed in owls, its applicability to mammals has been challenged by recent physiological results suggesting that, at least in small-headed species, ITDs are represented by a nontopographic population rate code, which involves only two opponent (left and right) channels, broadly tuned to ITDs from the two auditory hemifields. The current study investigates which of these two models of ITD processing is more likely to apply to humans. For that, evoked responses to abrupt changes in the ITDs of otherwise continuous sounds were measured with electroencephalography. The ITD change was either away from (“outward” change) or toward the midline (“inward” change). According to the opponent-channel model, the response to an outward ITD change should be larger than the response to the corresponding inward change, whereas the topographic model would predict similar response sizes for both conditions. The measured response sizes were highly consistent with the predictions of the opponent-channel model and contravened the predictions of the topographic model, suggesting that, in humans, ITDs are coded nontopographically. The hemispheric distributions of the ITD change responses suggest that the majority of ITD-sensitive neurons in each hemisphere are tuned to ITDs from the contralateral hemifield.
Estimated Cochlear Delays in Low Best-Frequency Neurons in the Barn Owl Cannot Explain Coding of Interaural Time Difference
Authors: Singheiser Martin , Fischer Brian J. , Wagner Hermann
Published: August 2010

The functional role of the low-frequency range (<3 kHz) in barn owl hearing is not well understood. Here, it was tested whether cochlear delays could explain the representation of interaural time difference (ITD) in this frequency range. Recordings were obtained from neurons in the core of the central nucleus of the inferior colliculus. The response of these neurons varied with the ITD of the stimulus. The response peak shared by all neurons in a dorsoventral penetration was called the array-specific ITD and served as criterion for the representation of a given ITD in a neuron. Array-specific ITDs were widely distributed. Isolevel frequency response functions obtained with binaural, contralateral, and ispilateral stimulation exhibited a clear response peak and the accompanying frequency was called the best frequency. The data were tested with respect to predictions of a model, the stereausis model, assuming cochlear delays as source for the best ITD of a neuron. According to this model, different cochlear delays determined by mismatches between the ipsilateral and contralateral best frequencies are the source for the ITD in a binaural neuron. The mismatch should depend on the best frequency and the best ITD. The predictions of the stereausis model were not fulfilled in the low best-frequency neurons analyzed here. It is concluded that cochlear delays are not responsible for the representation of best ITD in the barn owl.
Evaluation of the Impact That PARs Have on the Hydrogen Risk in the Reactor Containment: Methodology and Application to PSA Level 2
Authors: Bentaib Ahmed , Caroli Cataldo , Chaumont Bernard , Chevalier-Jabet Karine
Published: August 2010

This paper presents a methodology and its application to a Level 2 Probabilistic Safety Assessment (PSA-2), to evaluate the impact of the Passive Autocatalytic Recombiners (PARs) on the hydrogen risk in the reactor containment in case of a severe accident. Among the whole set of accidental scenarios calculated in the framework of the PSA-2, nine have been selected as representative in terms of the in-vessel hydrogen production rate and in-vessel total produced hydrogen mass. Five complementary scenarios have been added as representative of the core reflooding situations. For this set of selected scenarios the evolution of the conditions in the containment (i.e., pressure, temperature, and composition) during the in-vessel phase of the accident has been evaluated by means of a lumped parameter approach. The use of spray systems in the containment has also been considered as well as the presence of recombiners. Moreover, the ignition by recombiners of the flammable atmosphere has been considered.
Particle Swarm Optimization with Various Inertia Weight Variants for Optimal Power Flow Solution
Authors: Umapathy Prabha , Venkataseshaiah C. , Arumugam M. Senthil
Published: August 2010

This paper proposes an efficient method to solve the optimal power flow problem in power systems using Particle Swarm Optimization (PSO). The objective of the proposed method is to find the steady‐state operating point which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow, and voltage. Three different inertia weights, a constant inertia weight (CIW), a time‐varying inertia weight (TVIW), and global‐local best inertia weight (GLbestIW), are considered with the particle swarm optimization algorithm to analyze the impact of inertia weight on the performance of PSO algorithm. The PSO algorithm is simulated for each of the method individually. It is observed that the PSO algorithm with the proposed inertia weight yields better results, both in terms of optimal solution and faster convergence. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The algorithm is computationally faster, in terms of the number of load flows executed, and provides better results than other heuristic techniques.
Alternative Perspectives: How Chinese Medicine Understands Hypercholesterolemia
Authors: O'Brien Kylie A.
Published: August 2010

Treatment of cardiovascular disease, albeit under the auspices of other clinical descriptors to those described in western biomedicine, has a long history in China. Chinese Medicine (CM) is guided by unique philosophical underpinnings and theories. There are differences in how the heart is conceptualised traditionally in CM compared to biomedicine. This paper focusses on how hypercholesterolemia is understood from within the Chinese medical paradigm, including its aetiology, pathogenesis, and treatment. A brief overview of the key characteristics and theories of CM is given to provide context. Modern science has demonstrated that many Chinese herbs have cholesterol-lowering properties. Examples of research into individual herbs and medicinal formulae, combinations of herbs are presented. At a more sophisticated level, some researchers are challenging some of the very assumptions upon which CM is based, including applicability of CM theory to modern clinical entities such as hypercholesterolemia, and are seeking intersections of knowledge between CM and biomedicine that may extend CM theory.
On a Higher‐Order Difference Equation
Authors: Iričanin Bratislav D. , Liu Wanping
Published: August 2010

We describe in an elegant and short way the behaviour of positive solutions of the higher‐order difference equation xn = cxn−pxn−p−q/xn−q, n ∈ ℕ0, where p, q ∈ ℕ and c > 0, extending some recent results in the literature.
Synthesis of Vertically Aligned Dense ZnO Nanowires
Authors: Gong Lihong , Wu Xiang , Chen Huibo , Qu Fengyu , An Maozhong
Published: August 2010

We reported the synthesis of vertically aligned dense ZnO nanowires using Zn powder as the source material by a hydrothermal method and a postannealing process at 200°C. The as-synthesized ZnO nanowires are 100–200 nm in diameter and several micrometers in length and each nanowire has a tapered tip. The morphologies of the products remain after post-annealing treatment. Structural analysis indicates the ZnO nanowire is single crystalline and grows along the [0001] direction. The possible growth mechanism for ZnO nanowire bundles is proposed.
An Experimental Study on the Shape Changes of TiO2Nanocrystals Synthesized by Microemulsion-Solvothermal Method
Authors: Kong Wei , Liu Bo , Ye Bo , Yu Zhongping , Wang Hua , Qian Guodong , Wang Zhiyu
Published: August 2010

Titanium dioxide (TiO2) nanocrystals of different shape were successfully synthesized in a new microemulsion system through a solvothermal process. The TiO2nanocrystals were prepared from the reaction of tetrabutyl titanate (TBT),H2O, and oleic acid (OA), which were used as solvent and surfactant at 300∘Cand 240∘Cin a stainless steel autoclave. The sphere, polygon, and rhombus-shaped nanocrystals have been prepared at 300∘Cand the dot- and- rod shaped nanocrystals have been synthesized at 240∘C. The effect of the reaction time on the shape and size of TiO2nanocrystals in this method was studied in the present paper. The size distribution of TiO2nanocrystals prepared at 300∘Cfor different hours is also studied. In addition, an attempt to describe the mechanism of shape change of TiO2nanocrystals was presented in this paper.
Photocatalytic Degradation of Nitro and Chlorophenols Using Doped and Undoped Titanium Dioxide Nanoparticles
Authors: Ilyas Hassan , Qazi Ishtiaq A. , Asgar Wasim , Awan M. Ali , Khan Zahir-ud-din
Published: August 2010

Pure and Ag-TiO2nanoparticles were synthesized, with the metallic doping being done using the Liquid Impregnation (LI) method. The resulting nanoparticles were characterized by analytical methods such as scanning electron micrographs (SEMs), Energy Dispersive Spectroscopy (EDS), and X-ray diffraction (XRD). XRD analysis indicated that the crystallite size ofTiO2was 27 nm to 42 nm while the crystallite size of Ag-TiO2was 11.27 nm to 42.52 nm. The photocatalytic activity of pureTiO2and silver dopedTiO2was tested by photocatalytic degradation ofp-nitrophenol as a model compound. Ag-TiO2nanoparticles exhibited better results (98% degradation) as compared to pureTiO2nanoparticles (83% degradation) in 1 hour for the degradation ofp-nitrophenol. Ag-TiO2was further used for the photocatalytic degradation of 2,4-dichlorphenol (99% degradation), 2,5-dichlorophenol (98% degradation), and 2,4,6-trichlorophenol (96% degradation) in 1 hour. The degree of mineralization was tested by TOC experiment indicating that 2,4-DCP was completely mineralized, while 2,5-DCP was mineralized upto 95 percent and 2,4,6-TCP upto 86 percent within a period of 2 hours.
Electronic-Excitation-Induced Processing in GaSb Compound Nanoparticles
Authors: Yasuda H. , Mori H.
Published: August 2010

Temperature dependence of electronic-excitation-induced structural changes in nanoparticles has been studied by in situ transmission electron microscopy. When GaSb nanoparticles kept at 340 K were excited by 25 keV electrons, the compound transforms to the porous compound or the two-phase structure consisting of an antimony core and a gallium shell with increasing the total electron dose. On the other hand, in GaSb nanoparticles kept at 293 K the structure remains the original compound phase. It is suggested that such temperature dependence of the structural changes may arise from synergetic behaviors of point defects introduced athermally by the excitation and thermal mobility.
Study of the P-Type Doping Properties of ZnS Nanocrystals
Authors: Ma Xiying
Published: August 2010

The paper presents the study of p-type doping properties of ZnS nanocrystals (Ncs) using the local density approximation theory (LDA). Doping with single species of N, P, or As, ZnS nanocrystals are found to have a low-doping concentration and efficiency, which may be limited by the large expelling effect between Zn and impurity atoms and the compensation action from interstitialZnintatoms that can offer donor states to compensate the acceptors. To decrease the expelling and the compensation effect, composite dopants, such as N jointed with Ga, In, or Al are applied to codope ZnS nanocrystals. As a result, ZnS nanocrystals in p-type with high doping density and efficient are completed.
CDX2 Regulates Multidrug Resistance 1 Gene Expression in Malignant Intestinal Epithelium
Authors: Takakura Yuji , Hinoi Takao , Oue Naohide , Sasada Tatsunari , Kawaguchi Yasuo , Okajima Masazumi , Akyol Aytekin , Fearon Eric R. , Yasui Wataru , Ohdan Hideki
Published: August 2010

The caudal-related homeobox transcription factor CDX2 has a key role in intestinal development and differentiation. CDX2 heterozygous mutant mice develop colonic polyps, and loss of CDX2 expression is seen in a subset of colon carcinomas in humans. Ectopic CDX2 expression in the stomach of transgenic mice promotes intestinal metaplasia, and CDX2 expression is frequently detected in intestinal metaplasia in the stomach and esophagus. We sought to define CDX2-regulated genes to enhance knowledge of CDX2 function. HT-29 colorectal cancer cells have minimal endogenous CDX2 expression, and HT-29 cells with ectopic CDX2 expression were generated. Microarray-based gene expression studies revealed that the Multidrug Resistance 1 (MDR1/P-glycoprotein/ABCB1) gene was activated by CDX2. Evidence that the MDR1 gene was a direct transcriptional target of CDX2 was obtained, including analyses with MDR1 reporter gene constructs and chromatin immunoprecipitation assays. RNA interference–mediated inhibition of CDX2 decreased endogenous MDR1 expression. In various colorectal cancer cell lines and human tissues, endogenous MDR1 expression was well correlated to CDX2 expression. Overexpression of CDX2 in HT-29 cells revealed increased resistance to the known substrate of MDR1, vincristine and paclitaxel, which was reversed by an MDR1 inhibitor, verapamil. These data indicate that CDX2 directly regulates MDR1 gene expression through binding to elements in the promoter region. Thus, CDX2 is probably important for basal expression of MDR1, regulating drug excretion and absorption in the lower gastrointestinal tract, as well as for multidrug resistance to chemotherapy reagent in CDX2-positive gastrointestinal cancers. Cancer Res; 70(17); 6767–78. ©2010 AACR.
Effects of Siltuximab on the IL-6–Induced Signaling Pathway in Ovarian Cancer
Authors: Guo Yuqi , Nemeth Jeffrey , O'Brien Colin , Susa Michiro , Liu Xianzhe , Zhang Zhan , Choy Edwin , Mankin Henry , Hornicek Francis , Duan Zhenfeng
Published: August 2010

Purpose: To explore potential therapeutic strategies for interrupting the interleukin-6 (IL-6) signaling pathway, we measured IL-6 expression in ovarian cancer tissues, and evaluated the effects of a monoclonal anti-IL-6 antibody; siltuximab (CNTO 328), on levels of IL-6–induced Stat3 phosphorylation, Stat3 nuclear translocation, and Stat3 downstream antiapoptotic genes. We then looked for enhancing paclitaxel sensitivity in multidrug-resistant ovarian cancer cell lines.

Experimental Design: Expressions of IL-6 in ovarian cancer patient specimens were assessed by immunohistochemistry. Effects of siltuximab on IL-6–induced activation of Stat3 in an ovarian cancer cell line were determined by Western blot and real-time analysis of Stat3 nucleocytoplasmic translocation. Influence of combination of siltuximab and paclitaxel on tumor growth was evaluated in a xenograft mouse mode in vivo.

Results: Metastatic and drug-resistant recurrent tumors have significantly higher IL-6 expression when compared with the matched primary tumors. Siltuximab specifically suppressed IL-6–induced Stat3 phosphorylation and Stat3 nuclear translocation. Treatment with siltuximab significantly decreased the levels of Stat3 downstream proteins such as MCL-1, Bcl-XL, and survivin. Treatment with siltuximab reduced expression of multiple IL-6–induced genes in these cell lines. Furthermore, siltuximab increased the cytotoxic effects of paclitaxel in a paclitaxel resistant ovarian cancer cell line in vitro, but combination therapy with siltuximab did not have a significant effect on paclitaxel resistant tumor growth in vivo.

Conclusions: These results show that siltuximab effectively block the IL-6 signaling pathways and IL-6–induced gene expression. Blockage of IL-6 signaling may provide benefits for the treatment of ovarian cancer. Clin Cancer Res; 16(23); 5759–69. ©2010 AACR.
Global Reactivation of Epigenetically Silenced Genes in Prostate Cancer
Authors: Ibragimova Ilsiya , Ibáñez de Cáceres Inmaculada , Hoffman Amanda M. , Potapova Anna , Dulaimi Essel , Al-Saleem Tahseen , Hudes Gary R. , Ochs Michael F. , Cairns Paul
Published: August 2010

Transcriptional silencing associated with aberrant promoter hypermethylation is a common mechanism of inactivation of tumor suppressor genes in cancer cells. To globally profile the genes silenced by hypermethylation in prostate cancer, we screened a whole genome expression microarray for genes reactivated in the LNCaP, DU-145, PC-3, and MDA2b prostate tumor cell lines after treatment with the demethylating drug 5-aza-2-deoxycytidine and the histone deacetylation–inhibiting drug trichostatin A. A total of 2,997 genes showed at least 2-fold upregulation of expression after drug treatment in at least one prostate tumor cell line. For validation, we examined the first 45 genes, ranked by upregulation of expression, which had a typical CpG island and were known to be expressed in the normal cell counterpart. Two important findings were, first, that several genes known to be frequently hypermethylated in prostate cancer were apparent, and, second, that validation studies revealed eight novel genes hypermethylated in the prostate tumor cell lines, four of which were unmethylated in normal prostate cells and hypermethylated in primary prostate tumors (SLC15A3, 66%; KRT7, 54%; TACSTD2, 17%; GADD45b, 3%). Thus, we established the utility of our screen for genes hypermethylated in prostate cancer cells. One of the novel genes was TACSTD2/TROP2, a marker of human prostate basal cells with stem cell characteristics. TACSTD2 was unmethylated in prostatic intraepithelial neoplasia and may have utility in emerging methylation-based prostate cancer tests. Further study of the hypermethylome will provide insight into the biology of the disease and facilitate translational studies in prostate cancer. Cancer Prev Res; 3(9); 1084–92. ©2010 AACR.
DNA Methylation Markers for Prostate Cancer with a Stem Cell Twist
Authors: Jerónimo Carmen , Esteller Manel
Published: August 2010

This perspective on Ibragimova et al. (beginning on page 1084 in this issue of the journal) highlights the potential role of DNA methylation–based markers in the early detection of prostate cancer (PCa), with a focus on the global reactivation of expression of genes epigenetically silenced in PCa cell lines. Novel findings of these investigators identified four genes methylated specifically in PCa, including the stem cell marker TACSTD2, which seems to discriminate PCa (methylated TACSTD2) from prostatic intraepithelial neoplasia (unmethylated). These genes add significantly to the list of epigenetic markers showing promise for clinical early detection of PCa in the near future. Cancer Prev Res; 3(9); 1053–5. ©2010 AACR.