bluuebunny/crossref_metadata_2025 huggingface dataset:
Blockade of acid sensing ion channels attenuates the augmented exercise pressor reflex in rats with chronic femoral artery occlusion
Authors: Tsuchimochi Hirotsugu , Yamauchi Katsuya , McCord Jennifer L. , Kaufman Marc P.
Published: October 2011

Non‐technical summary  In patients with peripheral artery disease arterial blood flow to the legs is adequate at rest, but does not increase to meet metabolic demand of the muscles during exercise. Consequently, the arterial blood pressure response to exercise in these patients is greater than it is in healthy subjects. We tested the hypothesis that this exaggerated arterial pressure response to exercise is caused by the stimulation of the ion channel ASIC3 on the endings of sensory nerves in contracting skeletal muscle. We performed our experiments in decerebrated rats. Three days before the experiment, we ligated the left femoral artery, a manoeuvre which has been shown to simulate the arterial blood flow patterns to hindlimb skeletal muscles that are found in patients with peripheral artery disease. We found that blockade of ASIC3 with two different compounds attenuated the increase in arterial pressure evoked by left hindlimb muscle contraction.
A Posteriori Design Change Analysis for Complex Engineering Projects
Authors: Siddiqi Afreen , Bounova Gergana , de Weck Olivier L. , Keller Rene , Robinson Bob
Published: October 2011

Engineering changes are an inherent part of the design and development process and can play an important role in driving the overall success of the system. This work seeks to create a multidimensional understanding of change activity in large systems that can help in improving future design and development efforts. This is achieved by a posteriori analysis of design changes. It is proposed that by constructing a temporal, spatial, and financial view of change activity within and across these dimensions, it becomes possible to gain useful insights regarding the system of study. Engineering change data from the design and development of a multiyear, multibillion dollar development project of an offshore oil and gas production system is used as a case study in this work. It is shown that the results from such an analysis can be used for identifying better design and management strategies (in similar systems and projects) and for targeting design improvement in identified subsystems. The isolation and identification of change hotspots can be helpful in uncovering potential systemic design issues that may be prevalent. Similarly, strategic engineering and management decisions can be made if the major cost drivers are known.
Fabrication and Irradiance Mapping of a Low Cost Solar Simulator for Indoor Testing of Solar Collector
Authors: Hussain F. , Othman M. Y. H. , Yatim B. , Ruslan H. , Sopian K. , Anuar Z. , Khairuddin S.
Published: October 2011

The fabrication and testing of a solar simulator for indoor testing of solar collector are described. Consisting of Philips 500 W halogen lamps with built-in reflector, which are arranged at 30 cm apart, the system covers a test area suitable for a solar collector of size 120 cm by 53 cm. The height of the lamps above the solar collector under test is set to 160 cm. Measurement of the uniformity of the irradiance over the test area has been made. Four sets of irradiance mapping were performed at 466, 580, 686, and 804 W/m2, yielding at each point the irradiance uniformity percentage of 8.9, 7.6, 6.9, and 7.8%, respectively. The infrared radiation produced by the lamps was filtered by air flowing over the test area.
Multi-Objective Collaborative Optimization Based on Evolutionary Algorithms
Authors: Ruiyi Su , Liangjin Gui , Zijie Fan
Published: October 2011

This paper proposes a novel multi-objective collaborative optimization (MOCO) approach based on multi-objective evolutionary algorithms for complex systems with multiple disciplines and objectives, especially for those systems in which most of the disciplinary variables are shared. The shared variables will conflict when the disciplinary optimizers are implemented concurrently. In order to avoid the confliction, the shared variables are treated as fixed parameters at the discipline level in most of the MOCO approaches. But in this paper, a coordinator is introduced to handle the confliction, which allocates more design freedom and independence to the disciplinary optimizers. A numerical example is solved, and the results are discussed.
Some Recent Advances in the Integrated Layout Design of Multicomponent Systems
Authors: Zhang Weihong , Xia Liang , Zhu Jihong , Zhang Qiao
Published: October 2011

We provide an introduction and state of the art overview of integrated layout design of multicomponent systems. We review several packing optimization and overlap detection strategies, some tree-based methods, such as octrees and spheretrees, and a finite circle method (FCM) proposed to favor gradient-based optimization algorithms. Integrated layout design techniques for simultaneous packing and structure topology optimization of multicomponent systems are reviewed; two typical approaches for system stiffness maximization are reviewed and compared in detail. Design of multicomponent systems under inertia forces is presented using polynomial interpolation models; constraints to the centroid position, moment of inertia, and volume fraction are included. Applications to piezoelectric multi-actuated microtools and integrated layout design of bridge systems are presented. Finally, the effectiveness of the FCM, applications to 3D problems, and local optimum phenomena are discussed.
Experimental determination of heat capacities and their correlation with theoretical predictions
Authors: Mahmood Waqas , Sabieh Anwar Muhammad , Zia Wasif
Published: October 2011

We discuss an experiment for determining the heat capacities of various solids based on a calorimetric approach where the solid vaporizes a measurable mass of liquid nitrogen. We demonstrate our technique for copper and aluminum, and compare our data with Einstein’s model of independent harmonic oscillators and the more accurate Debye model. We also illustrate an interesting material property, the Verwey transition in magnetite.
Oscillations of a water column beneath trapped air
Authors: Brody Jed , Kasir Rafid , Weiss Daniel
Published: October 2011

We investigate the natural oscillations of a water column beneath air trapped in a tube and demonstrate that the frequency of oscillation is lowest when the tube is about half full of water, and is higher when the tube is either mostly full or mostly empty. The familiar concepts of hydrostatics, ideal gases, and damped harmonic motion are indispensible in the analysis of this challenging phenomenon.
Tryptophan Fix
Authors: Foley John F.
Published: October 2011

A tumor-derived tryptophan metabolite activates the aryl hydrocarbon receptor in an autocrine and paracrine manner to promote tumor progression.
How
Escherichia
coli
Got Its Stripes
Authors: Vinson Valda K.
Published: October 2011

A synthetic circuit implementing density-controlled bacterial motility autonomously produces a tunable stripe pattern.
Keep Your Distance
Authors: Mueller Kristen L.
Published: October 2011

Innate immune signaling and antimicrobial peptide activity maintain separation of the microbiota and intestinal epithelium.
Mucosal Microbe Melee
Authors: Mueller Kristen L.
Published: October 2011

Commensal microflora promote the pathogenesis of mucosally acquired viruses.
Promoting Glucose Homeostasis with an ER Stress Response
Authors: Wong Wei
Published: October 2011

Phosphorylation of a transcription factor induced by ER stress by p38 promotes glucose homeostasis.
Rapid Induction of Multiple Resistance Mechanisms in Aspergillus fumigatus during Azole Therapy: a Case Study and Review of the Literature
Authors: Camps Simone M. T. , van der Linden Jan W. M. , Li Yi , Kuijper Ed J. , van Dissel Jaap T. , Verweij Paul E. , Melchers Willem J. G.
Published: October 2011

Nine consecutive isogenic
Aspergillus fumigatus
isolates cultured from a patient with aspergilloma were investigated for azole resistance. The first cultured isolate showed a wild-type phenotype, but four azole-resistant phenotypes were observed in the subsequent eight isolates. Four mutations were found in the
cyp51A
gene of these isolates, leading to the substitutions A9T, G54E, P216L, and F219I. Only G54 substitutions were previously proved to be associated with azole resistance. Using a Cyp51A homology model and recombination experiments in which the mutations were introduced into a susceptible isolate, we show that the substitutions at codons P216 and F219 were both associated with resistance to itraconazole and posaconazole. A9T was also present in the wild-type isolate and thus considered a Cyp51A polymorphism. Isolates harboring F219I evolved further into a pan-azole-resistant phenotype, indicating an additional acquisition of a non-Cyp51A-mediated resistance mechanism. Review of the literature showed that in patients who develop azole resistance during therapy, multiple resistance mechanisms commonly emerge. Furthermore, the median time between the last cultured wild-type isolate and the first azole-resistant isolate was 4 months (range, 3 weeks to 23 months), indicating a rapid induction of resistance.
Effect of Usnic Acid on Candida orthopsilosis and C. parapsilosis
Authors: Pires Regina Helena , Lucarini Rodrigo , Mendes-Giannini Maria Jose Soares
Published: October 2011

The activity of usnic acid against
Candida orthopsilosis
and
Candida parapsilosis
on planktonic and biofilm conditions was investigated by using a broth microdilution and microplate methods. Potent
in vitro
activities against different
Candida
species were obtained. The metabolic activity of sessile cells of
C. parapsilosis
complex was reduced by 80% at four times the 80% inhibitory concentration. The
in vitro
studies support further efforts to determine whether usnic acid can be used clinically to cure patients with
Candida
infections.
Profound Alterations of Intestinal Microbiota following a Single Dose of Clindamycin Results in Sustained Susceptibility to Clostridium difficile-Induced Colitis
Authors: Buffie Charlie G. , Jarchum Irene , Equinda Michele , Lipuma Lauren , Gobourne Asia , Viale Agnes , Ubeda Carles , Xavier Joao , Pamer Eric G.
Published: October 2011

Antibiotic-induced changes in the intestinal microbiota predispose mammalian hosts to infection with antibiotic-resistant pathogens.
Clostridium difficile
is a Gram-positive intestinal pathogen that causes colitis and diarrhea in patients following antibiotic treatment. Clindamycin predisposes patients to
C. difficile
colitis. Here, we have used Roche-454 16S rRNA gene pyrosequencing to longitudinally characterize the intestinal microbiota of mice following clindamycin treatment in the presence or absence of
C. difficile
infection. We show that a single dose of clindamycin markedly reduces the diversity of the intestinal microbiota for at least 28 days, with an enduring loss of ca. 90% of normal microbial taxa from the cecum. Loss of microbial complexity results in dramatic sequential expansion and contraction of a subset of bacterial taxa that are minor contributors to the microbial consortium prior to antibiotic treatment. Inoculation of clindamycin-treated mice with
C. difficile
(VPI 10463) spores results in rapid development of diarrhea and colitis, with a 4- to 5-day period of profound weight loss and an associated 40 to 50% mortality rate. Recovering mice resolve diarrhea and regain weight but remain highly infected with toxin-producing vegetative
C. difficile
bacteria and, in comparison to the acute stage of infection, have persistent, albeit ameliorated cecal and colonic inflammation. The microbiota of “recovered” mice remains highly restricted, and mice remain susceptible to
C. difficile
infection at least 10 days following clindamycin, suggesting that resolution of diarrhea and weight gain may result from the activation of mucosal immune defenses.
Factor XI-Deficient Mice Display Reduced Inflammation, Coagulopathy, and Bacterial Growth during Listeriosis
Authors: Luo Deyan , Szaba Frank M. , Kummer Lawrence W. , Johnson Lawrence L. , Tucker Erik I. , Gruber Andras , Gailani David , Smiley Stephen T.
Published: October 2011

In mice infected sublethally withListeria monocytogenes, fibrin is deposited at low levels within hepatic tissue, where it functions protectively by limiting bacterial growth and suppressing hemorrhagic pathology. Here we demonstrate that mice infected with lethal doses ofL. monocytogenesproduce higher levels of fibrin and display evidence of systemic coagulopathy (i.e., thrombocytopenia, fibrinogen depletion, and elevated levels of thrombin-antithrombin complexes). When the hepatic bacterial burden exceeds 1 × 106CFU, levels of hepatic fibrin correlate with the bacterial burden, which also correlates with levels of hepatic mRNA encoding the hemostatic enzyme factor XI (FXI). Gene-targeted FXI-deficient mice show significantly improved survival upon challenge with high doses ofL. monocytogenesand also display reduced levels of hepatic fibrin, decreased evidence of coagulopathy, and diminished cytokine production (interleukin-6 [IL-6] and IL-10). While fibrin limits the bacterial burden during sublethal listeriosis in wild-type mice, FXI-deficient mice display a significantly improved capacity to restrain the bacterial burden during lethal listeriosis despite their reduced fibrin levels. They also show less evidence of hepatic necrosis. In conjunction with suboptimal antibiotic therapy, FXI-specific monoclonal antibody 14E11 improves survival when administered therapeutically to wild-type mice challenged with high doses ofL. monocytogenes.Together, these findings demonstrate the utility of murine listeriosis as a model for dissecting qualitative differences between protective and pathological host responses and reveal novel roles for FXI in exacerbating inflammation and pathogen burden during a lethal bacterial infection.
Renormalized three-body equations with short-range forces
Authors: Osman Ahmed
Published: October 2011

A three-body problem for a system of three nucleons interacting with short-range forces is discussed following effective field theory. Considering the case of a system of neutron–deuteron scattering, three-body equations are demonstrated such that the eigenvalues greater than unity are removed from the kernel leading to an equation that is renormalization-group invariant. The phase shifts are developed from a unique solution of the case of the doubled channel in neutron–deuteron scattering. The calculated neutron–deuteron phase shifts are well described below the deuteron breakup threshold.
Curvaton reheating and intermediate inflation in brane cosmology
Authors: Farajollahi Hossein , Ravanpak Arvin
Published: October 2011

In this paper, we study the curvaton reheating mechanism for an intermediate inflationary universe in brane world cosmology. In contrast to our previous work, we assume that when the universe enters the kination era, it is still in the high-energy regime. We then discuss, in detail, the new cosmological constraints on both the model parameters and the physical quantities.
Modeling of heavy ion collisions using radial basis function and generalized regression neural networks
Authors: El-Dahshan El-Sayed A.
Published: October 2011

Artificial neural networks (ANNs) have been applied to heavy ion collisions. In the present work, the possibility of using ANN methods for modeling the multiplicity distributions, P(ns), of shower particles produced from p, d, 4He, 6Li, 7Li, 12C, 16O, and 24Mg interactions with light (CNO) as well as heavy (AgBr) emulsions at 4.5 A GeV/c was investigated. Two different ANN approaches, namely radial basis function neural network (RBFNN) and generalized regression neural network (GRNN), were employed to obtain a mathematical formula describing these collisions. The results from RBFNN and GRNN models showed good agreement with the experimental data. GRNN models have a better performance than the RBFNN models. This study showed that the RBFNN and GRNN models are capable of accurately predicting the P(ns) of shower particles in the training and testing phases.
Decision-making techniques for software architecture design
Authors: Falessi Davide , Cantone Giovanni , Kazman Rick , Kruchten Philippe
Published: October 2011

The architecture of a software-intensive system can be defined as the set of relevant design decisions that affect the qualities of the overall system functionality; therefore, architectural decisions are eventually crucial to the success of a software project. The software engineering literature describes several techniques to choose among architectural alternatives, but it gives no clear guidance on which technique is more suitable than another, and in which circumstances. As such, there is no systematic way for software engineers to choose among decision-making techniques for resolving tradeoffs in architecture design. In this article, we provide a comparison of existing decision-making techniques, aimed to guide architects in their selection. The results show that there is no “best” decision-making technique; however, some techniques are more susceptible to specific difficulties. Hence architects should choose a decision-making technique based on the difficulties that they wish to avoid. This article represents a first attempt to reason on meta-decision-making, that is, the issue of deciding how to decide.
On nonmetric similarity search problems in complex domains
Authors: Skopal Tomáš , Bustos Benjamin
Published: October 2011

The task of similarity search is widely used in various areas of computing, including multimedia databases, data mining, bioinformatics, social networks, etc. In fact, retrieval of semantically unstructured data entities requires a form of aggregated qualification that selects entities relevant to a query. A popular type of such a mechanism is similarity querying. For a long time, the database-oriented applications of similarity search employed the definition of similarity restricted to metric distances. Due to its topological properties, metric similarity can be effectively used to index a database which can then be queried efficiently by so-called metric access methods. However, together with the increasing complexity of data entities across various domains, in recent years there appeared many similarities that were
not
metrics—we call them
nonmetric
similarity functions. In this article we survey domains employing nonmetric functions for effective similarity search, and methods for efficient nonmetric similarity search. First, we show that the ongoing research in many of these domains requires complex representations of data entities. Simultaneously, such complex representations allow us to model also complex and computationally expensive similarity functions (often represented by various matching algorithms). However, the more complex similarity function one develops, the more likely it will be a nonmetric. Second, we review state-of-the-art techniques for efficient (fast) nonmetric similarity search, concerning both exact and approximate search. Finally, we discuss some open problems and possible future research trends.
Dynamic access distance driven cache replacement
Authors: Feng Min , Tian Chen , Lin Changhui , Gupta Rajiv
Published: October 2011

In this article, we propose a new cache replacement policy that makes the replacement decision based on the reuse information of the cache lines and the requested data. We present the architectural support and evaluate the performance of our approach using SPEC benchmarks. We also develop two reuse information predictors: a profile-based static predictor and a runtime predictor. The applicability of each predictor is discussed in this paper. We further extend our reuse information predictors so that the cache can
adaptively
choose between the reuse information based replacement policy and an approximation of LRU policy. According to the experimental results, our adaptive reuse information based replacement policy performs either better than or close to the LRU policy. Our experiments show that L2 cache misses are reduced by 12.32% and 19.95% using the profiling-based static and runtime adaptive predictors respectively.
Evaluating placement policies for managing capacity sharing in CMP architectures with private caches
Authors: Samih Ahmad , Solihin Yan , Krishna Anil
Published: October 2011

Chip Multiprocessors (CMP) with distributed L2 caches suffer from a cache fragmentation problem; some caches may be overutilized while others may be underutilized. To avoid such fragmentation, researchers have proposed capacity sharing mechanisms where applications that need additional cache space can place their victim blocks in remote caches. However, we found that only allowing victim blocks to be placed on remote caches tends to cause a high number of remote cache hits relative to local cache hits.

In this article, we show that many of the remote cache hits can be converted into local cache hits if we allow newly fetched blocks to be selectively
placed
directly in a remote cache, rather than in the local cache. To demonstrate this, we use future trace information to estimate the near-upperbound performance that can be gained from combined placement and replacement decisions in capacity sharing. Motivated by encouraging experimental results, we design a simple, predictor-based, scheme called
Adaptive Placement Policy
(APP) that learns from past cache behavior to make a better decision on whether to place a newly fetched block in the local or remote cache. We found that across 50 multiprogrammed workload mixes running on a 4-core CMP, APP's capacity sharing mechanism increases aggregate performance by 29% on average. At the same time, APP outperforms the state-of-the-art capacity sharing mechanism that uses only replacement-based decisions by up to 18.2%, with a maximum degradation of only 0.5%, and an average improvement of 3%.
Approaches to disambiguating toponyms
Authors: Buscaldi Davide
Published: October 2011

Many approaches have been proposed in recent years in the context of Geographic Information Retrieval (GIR), mostly in order to deal with geographically constrained information in un-structured texts. Most of these approaches share a common scheme: in order to disambiguate a toponym
t
with
n
possible referents in a document
d
, they find a certain number of context toponyms
c
0
,...,
c

k

that are contained in
d.
A score for each referent is calculated according to the context toponyms, and the referent with the highest score is selected. According to the method used to calculate the score, Toponym Disambiguation (TD) methods may be grouped into three main categories, as proposed by [7]:

•
map-based:
methods that use an explicit representation of toponyms on a map, for instance to calculate the average distance of unambiguous context toponyms from referents;

•
knowledge-based:
methods that exploit external knowledge sources such as gazetteers, Wikipedia or ontologies to find disambiguation clues;

•
data-driven
or
supervised:
methods based on machine learning techniques.
Relevance ranking in Geographical Information Retrieval
Authors: Cai Guoray
Published: October 2011

The study of relevance is one of the central themes in information science where the concern is to match information objects with expressed information needs of the users. Despite substantial advances in search engines and information retrieval (IR) systems in the past decades, this seemingly intuitive concept of relevance remains to be an illusive one to define and even more challenging to model computationally [5, 13]. Geographical information retrieval extends and advances traditional IR methods with a spatial (or geographical dimension) of document representation and relevance measures.
Evaluating Geographic Information Retrieval
Authors: Cardoso Nuno
Published: October 2011

In GIR, as a research field branching from IR, initial evaluation initiatives were unsurprisingly inspired from established IR evaluation models. The GeoCLEF evaluation [6], which I will look into in some detail below, follows such a model. While this model suits the goal of a generic evaluation for all types of GIR systems, other evaluation initiatives forked so that particularly geographic challenges of the task could be more thoroughly focused on. NTCIR [7], with its GeoTime task, looked to include time expressions and had a topic set that resembles more questions that stir up the focus from retrieval, and more on reasoning.
Strategic and Tactical Design of Competing Decentralized SupplyChain Networks with Risk‐Averse Participants for Markets withUncertain Demand
Authors: Hafezalkotob Ashkan , Makui Ahmad , Sadjadi Seyed Jafar
Published: October 2011

An integrated equilibrium model for tactical decisions in network design is developed. We consider a decentralized supply chain network operating in markets under uncertain demands when there is a rival decentralized chain. The primary assumption is that two chains provide partial substitutable products to the markets, and markets′ demands are affected by tactical decisions such as price, service level, and advertising expenditure. Each chain consists of one risk‐averse manufacturer and a set of risk‐averse retailers. The strategic decisions are frequently taking precedence over tactical ones. Therefore, we first find equilibrium of tactical decisions for each possible scenario of supply chain network. Afterwards, we find optimal distribution network of the new supply chain by the scenario evaluation method. Numerical example, including sensitivity analysis will illustrate how the conservative behaviors of chains′ members affect expected demand, profit, and utility of each distribution scenario.
A Truthful Bilateral Multiunit Auction for Heterogeneous Cognitive Radio Networks
Authors: Su Jinzhao , Wang Jianfei , Wu Wei
Published: October 2011

Dynamic spectrum access technology has attracted much attention for its capability of improving spectrum efficiency. For attracting primary users to participate in secondary spectrum market, an auction was proposed as an alternative for spectrum trade. Existing auction schemes are either to be unilateral trade which only supports heterogeneous cognitive radio networks without guarantee of bid truthfulness, or to be truthful single-unit auction which only supports homogeneous channels. Few of them could comprehensively take all aspects of actual spectrum trade into consideration, such as spectrum allocation and reusability, channel diversity, and economic property. A truthful bilateral multiunit auction scheme which has characteristics of supporting heterogeneous networks (TBMAH) and polynomial complexity is proposed in this paper. We do experiments with both simulation and real networks, and the results show that TBMAH trades more spectrum resources than TRUST by 13.01% on average.
The Role of Cytokine in the Lupus Nephritis
Authors: Iwata Yasunori , Furuichi Kengo , Kaneko Shuichi , Wada Takashi
Published: October 2011

Lupus nephritis (LN)
is a major clinical manifestation of systemic
lupus erythematosus (SLE). Although numerous
abnormalities of immune system have been
proposed, cytokine overexpression plays an
essential role in the pathogenesis of LN. In the
initial phase of the disease, the
immune deposits and/or autoantibodies induce
cytokine production in renal resident cells,
leading to further inflammatory
cytokine/chemokine expression and leukocyte
infiltration and activation. Then, infiltrate
leukocytes, such as macrophages (Mφ) and dendritic cells (DCs), secrete a variety of
cytokines and activate naïve T cells, leading the cytokine
profile towards T helper (Th)1, Th2, and/or Th17. Recent studies
revealed these inflammatory processes in experimental animal
models as well as human LN. The cytokine targeted intervention may
have the therapeutic potentials for LN. This paper focuses on the
expression of cytokine and its functional role in the pathogenesis
of LN.
Degrading Endocrine Disrupting Chemicals from Wastewater by Photocatalysis: A Review
Authors: Sin Jin-Chung , Lam Sze-Mun , Mohamed Abdul Rahman , Lee Keat-Teong
Published: October 2011

Widespread concerns continue to be raised about the impacts of exposure to chemical compounds with endocrine disrupting activities. To date, the percolation of endocrine disrupting chemical (EDC) effluent into the aquatic system remains an intricate challenge abroad the nations. With the innovation of advanced oxidation processes (AOPs), there has been a consistent growing interest in this research field. Hence, the aim of this paper is to focus one such method within the AOPs, namely, heterogeneous photocatalysis and how it is used on the abatement of EDCs, phthalates, bisphenol A and chlorophenols in particular, using TiO2-based catalysts. Degradation mechanisms, pathways, and intermediate products of various EDCs for TiO2photocatalysis are described in detail. The effect of key operational parameters on TiO2photocatalytic degradation of various EDCs is then specifically covered. Finally, the future prospects together with the challenges for the TiO2photocatalysis on EDCs degradation are summarized and discussed.
Eph-B2/Ephrin-B2 Interaction Plays a Major Role in the Adhesion and Proliferation of Waldenstrom's Macroglobulinemia
Authors: Azab Feda , Azab Abdel Kareem , Maiso Patricia , Calimeri Teresa , Flores Ludmila , Liu Yang , Quang Phong , Roccaro Aldo M. , Sacco Antonio , Ngo Hai T. , Zhang Yong , Morgan Brittany L. , Carrasco Ruben D. , Ghobrial Irene M.
Published: October 2011

Purpose: The ephrin receptors (Eph) are found in a wide range of cancers and correlate with metastasis. In this study, we characterized the role of Eph-B2 receptor in the interaction of Waldenstrom's macroglobulinemia (WM) cells with the bone marrow microenvironment.

Experimental Design: We screened the activity of different receptor tyrosine kinases in WM patients and found that Eph-B2 was overexpressed compared with control. Also, we tested the expression of ephrin-B2 ligand on endothelial cells and bone marrow stromal cells (BMSC) isolated from WM patients. We then tested the role of Eph-B2/Ephrin-B2 interaction in the adhesion of WM cells to endothelial cells and BMSCs; the cell signaling induced by the coculture in both the WM cells and the endothelial cells; WM cell proliferation, apoptosis, and cell cycle in vitro and tumor progression in vivo; and in angiogenesis.

Results: Eph-B2 receptor was found to be activated in WM patients compared with control, with a 5-fold increase in CD19+ WM cells, and activated cell adhesion signaling, including focal adhesion kinase, Src, P130, paxillin, and cofilin, but decreased WM cell chemotaxis. Ephrin-B2 ligand was highly expressed on endothelial cells and BMSCs isolated from WM patients and on human umbilical vein endothelial cells and induced signaling in the endothelial cells promoting adhesion and angiogenesis. Blocking of ephrin-B2 or Eph-B2 inhibited adhesion, cytoskeletal signaling, proliferation, and cell cycle in WM cells, which was induced by coculture with endothelial cells and decreased WM tumor progression in vivo.

Conclusion: Ephrin-B2/Eph-B2 axis regulates adhesion, proliferation, cell cycle, and tumor progression in vivo through the interaction of WM with the cells in the bone marrow microenvironment. Clin Cancer Res; 18(1); 91–104. ©2011 AACR.
Focal Intradural Brain Infections in Children: An Analysis of Management and Outcome
Authors: Madhugiri Venkatesh S. , Savitr Sastri B.V. , Srikantha Umesh , Banerjee Anirban Deep , Somanna Sampath , Devi B. Indira , Chandramouli B.A. , Pandey Paritosh
Published: October 2011

Introduction: Focal intradural infections of the brain include empyema and abscess in the supratentorial and infratentorial spaces. These are amenable to surgical management. Various other issues may complicate the course of management, e.g. hydrocephalus with infratentorial lesions or cortical venous thrombosis with supratentorial lesions. Here, we review the management and identify factors affecting outcome in these patients. Materials and Methods: This is a retrospective analysis of all children (aged <18 years) treated at the National Institute of Mental Health and Neurosciences, Bangalore, India, between 1988 and 2004. Case records were analyzed to obtain clinical, radiological, bacteriological and follow-up data. Results: There were 231 children who underwent treatment for focal intradural abscess/empyema at our institute. These included 57 children with cerebral abscess, 65 with supratentorial empyema, 82 with cerebellar abscess and 27 with infratentorial empyema. All patients underwent emergency surgery (which was either burr hole and aspiration of the lesion or craniotomy/craniectomy and excision/evacuation), along with antibiotic therapy, typically 2 weeks of intravenous and 4 weeks of oral therapy. The antibiotic regimen was empiric to begin with and was altered if any sensitivity pattern of the causative organism(s) could be established by culture. Hydrocephalus was managed with external ventricular drainage initially and with ventriculoperitoneal shunt if warranted. Mortality rates were 4.8% for cerebral abscess, 9.6% for cerebellar abscess, 10.8% for supratentorial subdural empyema and 3.7% for posterior fossa subdural empyema. The choice of surgery was found to have a strong bearing on the recurrence rates and outcome in most groups, with aggressive surgery with craniotomy leading to excellent outcomes with a low incidence of residual/recurrent lesions. Conclusions: Antibiotic therapy, emergency surgery and management of associated complications are the mainstays of treatment of these lesions. We strongly advocate early, aggressive surgery with antibiotic therapy in children with focal intradural infections.
Mutations and Pituitary Morphology in a Series of 82 Patients with PROP1 Gene Defects
Authors: Obermannova Barbora , Pfaeffle Roland , Zygmunt-Gorska Agata , Starzyk Jerzy , Verkauskiene Rasa , Smetanina Natalija , Bezlepkina Olga , Peterkova Valentina , Frisch Herwig , Cinek Ondrej , Child Christopher J. , Blum Werner F. , Lebl Jan
Published: October 2011

Background/Aims: Defects of the PROP1 gene are the most prevalent genetic cause of combined pituitary hormone deficiency. Previous observations in affected patients have shown pituitary size ranging from hypoplasia to overt pituitary mass and evolution of size over the lifespan. Methods: We evaluated pituitary size and morphology in PROP1-mutation carriers who originated from Central and Eastern Europe. We analyzed 112 pituitary magnetic resonance imaging (MRI) scans from 82 patients (42 males) aged 2.5–72.7 (median 16.6) years from 60 kindreds. Results: Among the 120 independent PROP1 alleles, the most prevalent mutations were delGA301/302 (99 alleles) and delA150 (13 alleles). Median pituitary height at first MRI was 4.7 mm (range 1.0–20.7) and median volume was 127.6 mm3 (range 7.5–3,087.0). Pituitary size did not differ between sexes and did not correlate with hormonal phenotype, but significantly decreased with increasing age. However, evaluation of individual values suggested a biphasic mode with increasing volume during childhood, peak in adolescence, and subsequent regression in adulthood. Conclusion: Although pituitary size was increased in a number of PROP1-deficient patients, none of them suffered permanent damage from pituitary mass; therefore, any proposed surgery should be postponed as long as possible and ultimately may not be necessary due to the self-limiting nature of the pituitary enlargement.
Unusual Complications of Percutaneous Epicardial Access and Epicardial Mapping and Ablation of Cardiac Arrhythmias
Authors: Koruth Jacob S. , Aryana Arash , Dukkipati Srinivas R. , Pak Hui-Nam , Kim Young-Hoon , Sosa Eduardo A. , Scanavacca Mauricio , Mahapatra Srijoy , Ailawadi Gorav , Reddy Vivek Y. , d'Avila Andre
Published: October 2011

Background—

Percutaneous epicardial access and mapping/ablation of cardiac arrhythmias are being increasingly performed. Although complications such as pericardial effusion are relatively common, other unusual complications may occur due to the complex anatomic architecture of the heart and surrounding tissues. In this report, we report a series of rare and unusual complications related to percutaneous epicardial procedures.

Methods and Results—

Between 2006 and 2011, 334 patients underwent attempts at percutaneous, subxiphoid access for epicardial mapping/ablation at 5 experienced centers. Seven selected complications are highlighted in this case series. Patient 1 had a 1-cm right ventricular pseudoaneurysm after several unsuccessful attempts at epicardial access. This was successfully managed conservatively. Patient 2 had intra-abdominal bleeding related to puncture of the left lobe of the liver during access that required surgical repair. Patient 3 had a subcapsular hepatic hematoma that was probably related to percutaneous access and was successfully managed conservatively. Patient 4 had severe pericardial bleeding followed by ventricular fibrillation, immediately after obtaining percutaneous epicardial access. A lacerated middle cardiac vein was repaired surgically. However, the patient ultimately died of complications. Patient 5 had a history of cardiothoracic surgery and developed a right ventricle-abdominal fistula after multiple attempts at percutaneous access. This was surgically repaired without major sequelae. Patient 6 had cardiac tamponade caused by a lacerated coronary sinus branch during epicardial catheter ablation and required surgical repair. Patient 7 had severe left coronary vasospasm and ventricular fibrillation during catheter manipulation in the pericardium. This complication was successfully managed with intracoronary nitrates.

Conclusions—

Though generally safe, percutaneous epicardial access and mapping/ablation can result in uncommon complications. Awareness of these rare complications may facilitate early detection and successful management.
Abnormal Response of Superior Sinoatrial Node to Sympathetic Stimulation Is a Characteristic Finding in Patients With Atrial Fibrillation and Symptomatic Bradycardia
Authors: Joung Boyoung , Hwang Hye Jin , Pak Hui-Nam , Lee Moon-Hyoung , Shen Changyu , Lin Shien-Fong , Chen Peng-Sheng
Published: October 2011

Background—

We hypothesized that unresponsiveness of superior sinoatrial node (SAN) to sympathetic stimulation is strongly associated with the development of symptomatic bradycardia in patients with atrial fibrillation (AF).

Methods and Results—

We performed 3D endocardial mapping in healthy controls (group 1, n=10) and patients with AF without (group 2, n=57) or with (group 3, n=15) symptomatic bradycardia at baseline and during isoproterenol infusion. Corrected SAN recovery time was abnormal in 0%, 11%, and 36% of groups 1, 2, and 3, respectively (
P
=0.02). At baseline, 90%, 26%, and 7% (
P
<0.001) of the patients had multicentric SAN activation patterns. For groups 1, 2, and 3, the median distance from the superior vena cava-right atrial junction to the most cranial earliest activation site (EAS) was 5.0 (25–75 percentile range, 3.5–21.3), 10.0 (4–20), and 17.5 (12–34) mm at baseline (
P
=0.01), respectively, and 4.0 (0–5), 5.0 (1–10), and 15.0 (5.4–33.3) mm, respectively, during isoproterenol infusion (
P
=0.01), suggesting an upward shift of EAS during isoproterenol infusion. However, although the EAS during isoproterenol infusion was at the upper one third of the crista terminalis in 100% of group 1 and 78% of group 2 patients, only 20% of group 3 patients showed a move of the EAS to that region (
P
<0.001).

Conclusions—

Superior SAN serves as the EAS during sympathetic stimulation in patients without AF and in most patients with AF without symptomatic bradycardia. In contrast, unresponsiveness of superior SAN to sympathetic stimulation is a characteristic finding in patients with AF and symptomatic bradycardia.
Using the Amazing atmosphere to Foster Student Learning and Interest in Meteorology
Authors: Barrett Bradford S. , Woods John E.
Published: October 2011

To engage students in active learning, the Oceanography Department at the United States Naval Academy developed a new, not-for-course-credit training activity for its students, the Severe Weather InField Training (SWIFT). In SWIFT, 10 students and 2 faculty members traveled to the Great Plains and met with operational and research meteorologists, led daily weather discussions, made daily convective forecasts, and verified their convective forecasts by observing severe storms. Participation was solicited from sophomore- and junior-level students. SWIFT built on similar activities developed by other universities with its particular emphasis on assessing student learning and broadening awareness of both Department of Defense and civilian career opportunities in meteorology. Assessment outcomes from SWIFT indicate that students deepened their understanding of severe weather processes, were equipped to use observational and modeling data in real time, applied course content to real-world situations, became active participants in science inquiry, were introduced to a variety of meteorology career options, and increased their interest in pursuing a science-related career.
The Joint Hurricane Test Bed: Its First Decade of Tropical Cyclone Research-To-Operations Activities Reviewed
Authors: Rappaport Edward N. , Jiing Jiann-Gwo , Landsea Christopher W. , Murillo Shirley T. , Franklin James L.
Published: October 2011

The Joint Hurricane Testbed (JHT) is reviewed at the completion of its first decade. Views of the program by hurricane forecasters at the National Hurricane Center, the test bed's impact on forecast accuracy, and highlights of the top-rated projects are presented. Key concerns encountered by the test bed are identified as possible “lessons learned” for future research-to-operations efforts. The paper concludes with thoughts on the potential changing role of the JHT.
Modeling and analysis of roundness error in friction drilling of aluminum silicon carbide metal matrix composite
Authors: Somasundaram G. , Rajendra Boopathy S. , Palanikumar K.
Published: October 2011

Friction drilling is a newer nontraditional hole-making chipless process, which is used to make holes in materials that are used in aerospace, automotive, commercial and industrial products, electronic packaging, and thermal management. In friction drilling, a rotating conical tool is applied to penetrate work-material and create a hole in single step. In this study, comprehensive analysis on friction drilling of Al/SiCp metal matrix composites is carried out. This article discusses the roundness (hole diameter accuracy) errors on dry friction-drilled holes. The parameters considered for the experiment are: the composition of workpiece, workpiece thickness, spindle speed, and feed rate. The effect of parameters on roundness errors is analyzed using experimental design matrix and empirical relation between the process parameters and roundness error is established using response surface methodology. Analysis of variance is used for analyzing the results. The influences of individual input process parameters on roundness error are analyzed and presented in this study.
Non-isothermal crystallization kinetics of polyethylene/carbon nanofiber composites
Authors: Adhikari Ananta R , Lozano Karen , Chipara Mircea
Published: October 2011

The effect of carbon nanofibers on the crystallization of polyethylene using differential scanning calorimetry operating in dynamical mode at various cooling rates (2, 4, 8, 15, and 30°C/min) is reported. Experimental data were analyzed using the Avrami, Ozawa, and the combined Avrami–Ozawa methods. It is concluded that the addition of carbon nanofibers modifies the crystallization process of polyethylene (changing the value of the Avrami exponent), and that the combined Avrami–Ozawa approach describes more accurately the crystallization of carbon nanofiber reinforced polyethylene composites. The analysis of the experimental data indicates that the dispersion of carbon nanofibers within polyethylene leads to complex changes in the crystallization process such as increased crystallization temperature, longer times to reach 50% crystallization, higher crystallization rates, and lower degrees of crystallinity of the polymeric component.
A comprehensive fatigue failure criterion based on thermodynamic approach
Authors: Naderi M. , Khonsari M.M.
Published: October 2011

In this work, stress curve and energy-based (linear elastic strain energy, and hysteresis loop energy) fatigue failure criteria are compared with a new, entropy-based model for the prediction of fatigue life in a woven glass/epoxy laminate. Extensive experimental results are reported that involve load-controlled tension–tension fatigue test with two different stress ratios as well as constant- and variable-loading of a woven glass/epoxy laminate with various load angles. The plot of fracture fatigue entropy vs. fatigue life is compared with the energy plotted vs. number of cycle and stress plotted vs. number of cycle (i.e., the so-called S–N curve) plots.
Preparation and characterization of a novel hydroxyapatite-wollastonite/silk fibroin composite
Authors: Zhao Song , Zhou Zhufa , Wu Jiang , Wang Shumei , Guo Xinshuang , Zhang Qiang
Published: October 2011

A novel hydroxyapatite-wollastonite/silk fibroin (AW/SF) composite was prepared for bone repair and replacement by a modified coprecipitation method. The wollastonite powders introduced in the composite were sintered with full crytallinity and ground to the diameter of 30–50 nm. The FT-IR and XRD analyses showed that the silk fibroin, wollastonite, and hydroxyapatite co-existed in the composite, but the newly formed hydroxyapatite had low crystallinity ascribing to the low temperature procedure. The composite exhibited both higher compressive strength (84.4 MPa) and Barcol hardness (48.5) than the hydroxyapatite/silk fibroin (HA/SF) composite without any wallostonite involved. And the composite in this work showed excellent bioactivities while held in simulated body fluid (SBF).
Examining the Role of Social Media in Effective Crisis Management
Authors: Jin Yan , Liu Brooke Fisher , Austin Lucinda L.
Published: October 2011

Publics increasingly use social media during crises and, consequently, crisis communication professionals need to understand how to strategically optimize these tools. Despite this need, there is scarce theory-grounded research to understand key factors that affect how publics consume crisis information via social media compared to other sources. To fill this gap, an emerging model helps crisis managers understand how publics produce, consume, and/or share crisis information via social media and other sources: the social-mediated crisis communication model (SMCC). This study tests essential components of the SMCC model through a 3 (crisis information form) x 2 (crisis information source) x 2 (crisis origin) mixed-design experiment ( N = 338). The findings indicate the key role of crisis origin in affecting publics’ preferred information form (social media, traditional media, or word-of-mouth communication) and source (organization in crisis or third party), which influences how publics anticipate an organization should respond to a crisis and what crisis emotions they are likely to feel when exposed to crisis information.