bluuebunny/crossref_metadata_2025 huggingface dataset:
Subcellular Localization and Role of Lipin-1 in Human Macrophages
Authors: Valdearcos Martín , Esquinas Esperanza , Meana Clara , Gil-de-Gómez Luis , Guijas Carlos , Balsinde Jesús , Balboa María A.
Published: April 2011

The lipins have been described as metabolic enzymes that regulate lipid biosynthesis and also signaling processes by controlling the cellular concentration of bioactive lipids, phosphatidic acid, and diacylgycerol. In the present work we have studied the subcellular localization and role of lipin-1 in human monocyte-derived macrophages. Human macrophages express lipin-1 isoforms α and β. A transfected lipin-1α–enhanced GFP construct associates with membranes of cellular organelles that can be stained with Nile Red. Colocalization experiments with lipid droplet (LD)-specific proteins such as adipophilin/adipose differentiation-related protein/perilipin 2 or TIP47/perilipin 3 show that both proteins colocalize with lipin-1α in the same cellular structures. Reduction of the expression levels of lipin-1 by small interfering RNA technology does not impair triacylglycerol biosynthesis but reduces the size of LDs formed in response to oleic acid. In agreement with these data, peritoneal macrophages from animals that carry a mutation in the Lpin-1 gene (fld animals) also produce less and smaller LDs in response to oleic acid. Mass spectrometry determinations demonstrate that the fatty acid composition of triacylglycerol in isolated LDs from lipin-1–deficient cells differs from that of control cells. Moreover, activation of cytosolic group IVA phospholipase A2α, a proinflammatory enzyme that is also involved in LD biogenesis, is also compromised in lipin-1–deficient cells. Collectively, these data suggest that lipin-1 associates with LDs and regulates the activation of cytosolic group IVA phospholipase A2α in human monocyte-derived macrophages.
Blockade of CTLA-4 Decreases the Generation of Multifunctional Memory CD4+ T Cells In Vivo
Authors: Rudolph Marion , Hebel Katrin , Miyamura Yoshinori , Maverakis Emanual , Brunner-Weinzierl Monika C.
Published: April 2011

CTLA-4 is known as a central inhibitor of T cell responses. It terminates T cell activation and proliferation and induces resistance against activation induced cell death. However, its impact on memory formation of adaptive immune responses is still unknown. In this study, we demonstrate that although anti–CTLA-4 mAb treatment during primary immunization of mice initially enhances the number of IFN-γ–producing CD4+ T cells, it does not affect the size of the memory pool. Interestingly, we find that the CTLA-4 blockade modulates the quality of the memory pool: it decreases the amount of specialized “multifunctional” memory CD4+ T cells coproducing IFN-γ, TNF-α, and IL-2 in response to Ag. The reduction of these cells causes an immense decrease of IFN-γ–producing T cells after in vivo antigenic rechallenge. Chimeric mice expressing CTLA-4–competent and –deficient cells unmask, which these CTLA-4–driven mechanisms are mediated CD4+ T cell nonautonomously. In addition, the depletion of CD25+ T cells prior to the generation of Ag-specific memory cells reveals that the constitutively CTLA-4–expressing natural regulatory T cells determine the quality of memory CD4+ T cells. Taken together, these results indicate that although the inhibitory molecule CTLA-4 damps the primary immune response, its engagement positively regulates the formation of a high-quality memory pool equipped with multifunctional CD4+ T cells capable of mounting a robust response to Ag rechallenge.
An Aberrant Thymus in CCR5−/− Mice Is Coupled with an Enhanced Adaptive Immune Response in Fungal Infection
Authors: Kroetz Danielle N. , Deepe George S.
Published: April 2011

CCR5 is a potent mediator of regulatory T cell (Treg) chemotaxis. In murine histoplasmosis, mice lacking CCR5 or endogenous CCL4 have a reduced number of Tregs in the lungs, which results in accelerated resolution of infection. In this study, we demonstrate that CCR5 controls the outcome of Histoplasma capsulatum infection by dictating thymic and lymph node egress of Tregs. Mice lacking CCR5 or treated with a mAb to CCL4 had more Tregs in the thymus prior to and during infection. Thymic accumulation was associated with diminished transcription of the sphingosine 1-phosphate 1 receptor and Krüppel-like factor 2, both of which regulate thymic and lymph node emigration of T cells. The significance of CCR5 in Treg egress was demonstrated by generating mixed bone marrow chimeras. Chimeric mice had an increased proportion of CCR5−/− Tregs in the thymus and lymph nodes and a decreased proportion of Tregs in the lungs prior to and during H. capsulatum infection. Hence, CCR5 signaling regulates pathogen persistence in murine histoplasmosis by regulating Tregs exiting from the thymus and lymph nodes and, consequently, their subsequent homing in the periphery.
Promyelocytic Leukemia Zinc Finger Turns on the Effector T Cell Program without Requirement for Agonist TCR Signaling
Authors: Savage Adam K. , Constantinides Michael G. , Bendelac Albert
Published: April 2011

Thymocytes expressing the NKT cell semi-invariant αβ TCR are thought to undergo agonist interactions with CD1d ligands prior to expressing promyelocytic leukemia zinc finger (PLZF), a broad complex, tramtrack, bric-a-brac, poxvirus, and zinc finger transcription factor that directs acquisition of the effector program of these innate-like T cells. Whether PLZF can mediate this effector conversion independently of agonist signaling has not been investigated. We demonstrated that transgenic (Tg) expression of PLZF under the CD4 promoter induced the innate effector program in two different MHC class II-restricted TCR-Tg Rag1−/− models examined. In CD4 thymocytes expressing a fixed Tg TCR β-chain, the associated TCRα sequences in wild-type and PLZF-Tg mice overlapped extensively, further demonstrating that PLZF could induce the effector program in most CD4 T cells that would normally be selected as naive cells. In contrast, PLZF altered the negative selection of thymocytes expressing TCR β-chains reactive against several retroviral superantigens. Thus, PLZF is remarkable in that it is a transcription factor capable of inducing an effector program in the absence of T cell agonist interactions or cell division. Its expression may also enhance the survival of agonist-signaled thymocytes.
Food Stamp Participation among Adult‐Only Households
Authors: Ribar David C. , Edelhoch Marilyn , Liu Qiduan
Published: April 2011

Several recent changes in the Food Stamp Program have been directed toward households without children, including new work requirements for able‐bodied adults without dependents (ABAWDs) and easier application and recertification procedures for the disabled and the elderly. Despite their relevance to policy makers, adult‐only households have not been extensively examined. We use administrative records from South Carolina to investigate how spells of food stamp participation for adult‐only households vary with ABAWD provisions, recertification intervals, and other characteristics. We find that households that were subject to ABAWD policies had shorter spells and lower rates of food stamp participation than other households. We also find that households were much more likely to leave the Food Stamp Program at recertification dates than at other dates. We further find that time limits were associated with exits with and without earnings, suggesting that this policy increased self‐sufficiency for some households but left others without support.
Costly Buyer Search in a Differentiated Products Model: An Experimental Study
Authors: Mago Shakun Datta
Published: April 2011

This study examines whether the content of buyer information and the timing of its dissemination affects seller market power. We construct laboratory markets with differentiated goods and costly buyer search in which sellers simultaneously post prices. The experiment varies the information on price or product characteristics that buyers learn under different timing assumptions (pre‐ and postsearch), generating four information treatments. Theory predicts that price information lowers the equilibrium price, but information about product characteristics increases the equilibrium price. That is, contrary to intuition, the presence of informed buyers may impart a negative externality on other uninformed buyers. Data support the model's negative externality result when sellers face a large number of robot buyers that are programmed to search optimally. Observed prices conform to the model's comparative statics and are broadly consistent with predicted levels. With human buyers, however, excessive search instigates increased price competition, and sellers post prices that are significantly lower than predicted.
Does Real Exchange Rate Volatility Affect Sectoral Trade Flows?
Authors: Caglayan Mustafa , Di Jing
Published: April 2011

This article investigates empirically the effect of real exchange rate volatility on sectoral bilateral trade flows between the United States and its top 13 trading partners. Our investigation also considers those effects on trade flows that may arise through changes in income volatility and the interaction between income and exchange rate volatilities. We provide evidence that (i) exchange rate volatility does not systematically affect sectoral trade flows, (ii) income volatility has little impact on trade flows, and (iii) the effect of the interaction term on trade flows is opposite that of exchange rate volatility, dampening its impact on trade flows.
Pretrial Bargaining with Asymmetric Information: Unilateral versus Bilateral Payoff Relevance
Authors: Farmer Amy , Pecorino Paul
Published: April 2011

Asymmetric information is a leading explanation for settlement failure that results in a costly trial. Typically, the information in question is assumed to have bilateral payoff relevance, meaning it affects the expected payoffs of both the plaintiff and defendant. When there is bilateral payoff relevance, trials may be predicted, regardless of whether it is the informed or uninformed party who makes the offer. However, there may be important cases in which information has unilateral payoff relevance. For example, if the plaintiff's risk preferences are private information, this information will affect the plaintiff's expected payoff at trial, but will have no effect on the expected payoff of the defendant. When there is unilateral payoff relevance, inefficient trials never occur when the informed party makes the offer. Trials can occur when the uninformed party makes the offer assuming that the private information affects the payoff of the individual holding the private information.
Institutions, Capital, and Growth
Authors: Hall Joshua C. , Sobel Russell S. , Crowley George R.
Published: April 2011

The international development community has encouraged investment in physical and human capital as a precursor to economic progress. Recent evidence shows, however, that increases in capital do not always lead to increases in output. We develop a growth model where the allocation and productivity of capital depends on a country's institutions. We find that increases in physical and human capital lead to output growth only in countries with good institutions. In countries with bad institutions, increases in capital lead to negative growth rates because additions to the capital stock tend to be employed in rent‐seeking and other socially unproductive activities.
The Elasticity of Taxable Income during the 1990s: New Estimates and Sensitivity Analyses
Authors: Giertz Seth H.
Published: April 2011

Over the past two decades, the elasticity of taxable income has emerged as the central parameter for assessing efficiency and revenue implications from changes to tax policy. This article estimates short‐ and longer‐run responses of taxable (and gross) income to changes in tax rates using panels of U.S. tax returns for the 1990s. With the richest set of income controls, income—weighted elasticity estimates range from 0.19 to 0.33, depending on whether responses are measured over one‐ or three‐year intervals. An alternative approach designed to capture delayed and anticipatory responses yields much larger estimates—ranging from 0.43 over the short term and from 0.78 to 1.46 over the longer term. A continuing obstacle to identification encountered here is that the income controls most likely to control for mean reversion and divergence within the income distribution are also the most likely to absorb independent variation in tax rates, also needed for identification.
FDI, Trade, and Product Innovation: Theory and Evidence
Authors: Lin Hui-lin , Lin Eric S.
Published: April 2011

This article investigates the relationship between foreign direct investment (FDI, including outward FDI and inward FDI), imports and exports, and product innovation. Our theoretical model predicts that inward FDI, outward FDI, imports, and exports have positive influences on firm innovative activities, which would evaluate the effects of the relative magnitude of different sources on innovation. The empirical results based on the 2003 First Taiwan Technological Innovation Survey confirm three of the proposed hypotheses for the entire sample. However, when focusing on the manufacturing sector, outward FDI, inward FDI, imports, and exports all exhibit strongly positive effects on the determination of conducting product innovation (i.e., the four hypotheses are verified). A consistent trend is that outward FDI has the largest effect on innovation, regardless of the measurement of product innovation and the division of the entire sample, which may imply that in Taiwan a positive effect of “deindustrialization” is to innovate more.
Liquidity Risk and Banks' Asset Composition: Implications for Monetary Policy
Authors: Ghossoub Edgar A.
Published: April 2011

Monetary growth models in which the government is a net debtor demonstrate that inflation adversely affects capital formation through the crowding out effect. Interestingly, the results are at odds with empirical evidence. In particular, recent studies point to an asymmetric relationship between inflation and the real economy across countries. Specifically, inflation and output are negatively correlated in poor countries. In contrast, inflation is associated with higher levels of economic activity in advanced economies. I present a monetary growth model with public debt, where the exposure to risk is inversely related to the level of income. In this setting, I demonstrate that the effects of monetary policy depend on the level of capital of the economy. In poor countries, banks' portfolios consist primarily of government liabilities. Therefore, a higher rate of money creation inhibits capital formation in these economies. In contrast, banks devote more resources toward productive uses in advanced countries. Consequently, monetary policy generates a Tobin effect.
Repeated Auctions with Impatient Bidders and Externalities
Authors: Rhee Ki-Eun
Published: April 2011

This article studies collusion in repeated auctions both among patient and among impatient bidders when the outside option of the participation constraint is endogenous due to negative externalities. We find that (i) there are no bidding wars along the equilibrium path both for patient and for impatient bidders; compared to the optimal collusive bidding scheme for patient bidders, that for impatient bidders involves (ii) a lower threshold type above which bidding starts when externalities are small or (iii) more frequent jumps in a bidding scheme when externalities are large. The results carry an empirical implication that we should observe either a higher probability of sales or a higher number of bid levels in auctions that are repeatedly offered in unstable markets than those offered in stable markets.
Targeting Teaching: An International Economics Classroom Experiment
Authors: Johnson Paul
Published: April 2011

This article describes a general equilibrium market experiment that allows students to generate goods prices, exchange rates, and trade flows by trading with each other. Instructors can set experiment parameters, and output data are automatically generated as a spreadsheet file. Exchange rate and current account dynamics are the outcome of student production and trading decisions. The source code is available without restrictions on modification or use.
The New Deal and Modern Memory
Authors: Shughart William F.
Published: April 2011

The “Great Recession,” which began at year‐end 2007, was precipitated by plunging real estate values, followed by borrower defaults and financial crisis for the public and private institutions that supplied loanable funds to the mortgage market. With economic growth not yet returned to trend, three years on more than 9% of the American labor force remains unemployed. Current macroeconomic events, perhaps inevitably, have been compared to those of the Great Depression of 1929–1933, both in terms of severity and of the efficacy of the public policies adopted ostensibly to restore prosperity. In this article, I review the literature on the New Deal, paying particular attention to modern scholarship emphasizing the role of presidential politics and antibusiness political rhetoric in deepening and prolonging the Great Depression. The parallels between then and now suggest that the two economic contractions had similar causes and elicited equally counterproductive policy responses.
On Delays in Project Completion with Cost Reduction: An Experiment
Authors: Sarkar Shubhro , Kwasnica Anthony M.
Published: April 2011

We examine the voluntary provision of a public project via binary contributions when contributions may be made over multiple periods. In many situations, early contributors are likely to pay a higher cost than those who wait. We show that in such circumstances the provision of the project always involves delay. Because this game involves coordination on complex, dynamic strategies in the face of asymmetries in payoffs, we examine behavior in the laboratory.
An Experimental Investigation of Asset Pricing in Segmented Markets
Authors: Ackert Lucy F. , Mazzotta Stefano , Qi Li
Published: April 2011

This article reports the results of experimental asset markets in which participants trade two assets with distinct dividend claims. Some traders are able to transact in the markets for both assets, whereas others can trade in only one market. When some are restricted from transacting in one market, the ineligible asset that cannot be traded by all commands a super risk premium. Without this premium, unrestricted investors would not hold all the available shares of the ineligible asset. In addition, we find that although unrestricted traders have the opportunity to remove all risk, few take advantage of this hedging opportunity.
International Business Alliance under Asymmetric Information: Technology vis‐à‐vis Information Advantage
Authors: Dai Chifeng , Lahiri Sajal
Published: April 2011

We study the relationship between a multinational corporation (MNC) and a domestic firm under demand uncertainty. The MNC possesses a superior production technology, but the domestic firm is better at predicting market demand. We examine the MNC's preference for, and the ownership structure of, an international alliance (IA) and find, inter alia, that binding borrowing constraints have serious implications for the results. Interestingly, a firm's preference for and profits in IA do not necessarily increase as its advantage in market information or production technology increases. We also consider a dynamic setting with technology spillover and show that whether technology spillover hinders or facilitates IA once again depends on the nature of the credit market.
The Effects of Food Stamps on Obesity
Authors: Baum Charles L.
Published: April 2011

Poverty has historically been associated with a decrease in food consumption. This at least partially changed in 1964 when the Food Stamp Act began guaranteeing food for those in poverty. Since the act's passage, the prevalence of obesity has increased dramatically, particularly among those with low incomes. This article examines the effects of the Food Stamp Program on the prevalence of obesity using 1979 National Longitudinal Survey of Youth data. Results indicate that food stamps have significant positive effects on obesity and the obesity gap for females, but these effects are relatively small, and consequently, such benefits are approximated to have played a minor role in increasing obesity at the aggregate level.
Identifying Price Discrimination When Product Menus Are Endogenous
Authors: Cohen Andrew
Published: April 2011

A well‐known approach to identifying second‐degree price discrimination is based on examining correlations between product menus and prices. When product menus are endogenous, however, tests for price discrimination may be biased by the fact that unobservables affecting costs or demand may jointly determine product menus and prices, leading one to falsely infer price discrimination. Using observed product characteristics or fixed effects to control for these unobservables confounds inference on the nature of price discrimination by potentially “overcorrecting” the original bias. I propose a difference‐indifferences approach that is robust to this critique. An application to the pricing of different package sizes of paper towels is presented.
Productivity, Trade, and Institutional Quality: A Panel Analysis
Authors: Doyle Eleanor , Martinez-Zarzoso Inmaculada
Published: April 2011

Recognizing that gains historically attributed to trade capture instead the roles of institutions and geography, we estimate the relationship between labor productivity and trade for a panel of countries, 1980 to 2000. We use real and nominal openness as measures of trade. The endogeneity of trade and institutional quality is accounted for with instruments. Our trade instrument is based on a theoretically motivated gravity equation and uses a more comprehensive data set than in related studies. Fixed‐ and random‐effects and system‐GMM panel estimation methods address potential biases associated with cross‐section estimations. We find a robust relationship between real openness and labor productivity from the 1990s. Countries that trade more generate higher levels of productivity, supporting an institutional theory of growth. We find evidence that countries with low‐quality institutions benefit from openness to trade and that the positive effect of trade on labor productivity is lower for more populated countries.
Assessor Incentives and Property Assessment
Authors: Ross Justin M.
Published: April 2011

While typically not a formulator of policy, property assessors are likely sensitive to political incentives, since they are either directly elected to their office or appointed by another elected official. This article estimates a model that is motivated by the assumption that assessors seek to maximize political support in a manner that affects the assessment‐to‐sales price ratio. With panel data from a 2001 to 2006 series of sales price ratio studies in Virginia cities and counties, a fixed effects variance‐decomposition regression reveals a variety of socioeconomic and political variables that bias the assessed value away from fair market value. In addition to finding influential socioeconomic factors, the results indicate that elected assessors underassess more than appointed assessors. Furthermore, it appears assessors try to export the property tax onto commercial property, and assessors in districts with higher measures of local government fiscal stress tend to give higher assessments.
Psychic distance revisited: A proposed conceptual framework and research agenda
Authors: Smith Max , Dowling Peter J , Rose Elizabeth L
Published: April 2011

The concept of psychic distance has had a long but problematic history in the academic study of international business. Although inherently appealing, attempts to empirically validate the theoretical frameworks proposed by early psychic distance scholars have provided mixed results. This has led a number of academics to question the usefulness of the concept. Theoretical advances have been made in recent times with the introduction of revised definitions, but there is still the need for a conceptual framework of psychic distance that unambiguously identifies the determinants of psychic distance and demonstrates the relevance of this concept at the national, firm, and individual level. The present paper proposes a revised definition of psychic distance and posits a conceptual framework of psychic distance that addresses these needs. It then concludes by putting forward a research agenda arising as a consequence of the new conceptual framework.
The mental models of HR professionals as strategic partners
Authors: Labedz Chester S , Lee Jegoo
Published: April 2011

In this paper, we elicited and examined mental models of human resource professionals, regarding the interrelationships of important elements in shaping competitive strategy, for consensus or systematic variation, testing for HR's distinctive contribution at the strategy table. In order to examine their mental models, we collected empirical data from a stratified non-probability respondent sample of HR professionals in three stages: semi-structured informant interviews; free list and rank ordering tasks; and drawing exercises. Performing consensus analysis of respondents' mental models, we found that: First, as a group, HR professionals lack a robust, integrated HR strategic perspective; second, consensus views of labor relations practitioners and business unit generalists emerge as most distinctive and most people-focused. As one of few scholarly empirical examinations of HR practitioners' mental models on their view as strategic partners, this study challenges the normative calls among scholars and professional organizations for HR's participation in strategy formulation.
The power of stories to persuade: The storying of midwives and the financial narratives of central policy makers
Authors: Dawson Patrick , Farmer Jane , Thomson Elizabeth
Published: April 2011

The power of stories to persuade in infl uencing the process of change is the focus of this article. Attention is given to the importance of stories in making sense of past experience, of unifying groups, and in presenting options for future engagement and action. Unlike the narrative concern with sequencing, coherence and the need for a beginning, middle and end, it is argued that stories are often partial and ongoing, occur at multiple levels compete, complement and redefine positions. The plurality and political nature of stories are illustrated in an analysis of data drawn from a longitudinal study of six health care sites in remote and rural Scotland. The study concludes by arguing that stories are a powerful political vehicle in influencing sense-making and a critical component in maintaining choice and defl ecting the imposition of a single simple solution (hegemonic influence) over various interpretations of what are complex context-based issues.
Co-existing institutional logics and agency among top-level public servants: A praxeological approach
Authors: Bjerregaard Toke
Published: April 2011

While institutional organization research to some extent has neglected the micro agency of organization members, parts of the strategy-as-practice research have tended to bracket off wider societal environments shaping the practices-in-use of top-level strategy practitioners. This article attempts to address parts of this void. This study examines the agency exerted by top-level public servants through their everyday strategy and policy work in face of co-existing logics of public administration. The findings illustrate how their action strategies span from more passive strategies of coping with coexisting logics of administration to more skilled agency of combining logics aimed at enhancing their opportunity and action space. The study suggests that the interplay between co-existing institutional logics, action strategies and the practical skills of top-level public servants provides the basis for both coping and more proactive strategies in pluralistic public administrations. Findings illustrate the role of public servants' practical sense of realizable opportunities that inform such strategies of handling co-existing institutional logics. Implications for institutional studies of organizations are outlined.
Agency and the deunionisation of managers in an Australian telecommunications company
Authors: Barton Ruth , van den Broek Diane
Published: April 2011

Discussions about deunionisation usually focus on lower levels of the workforce with managers seen as the initiators of deunionisation strategies. Managers, however, occupy contradictory positions as agents of capital, employees and possibly trade unionists. This can place them in the position of being both recipients and conduits in deunionisation strategies. The focus of the study is on Telstra, the major telecommunications carrier in Australia. Using a range of sources such as interviews and company and union materials, this qualitative research shows how between 1992 and 2000 Telstra's senior management's concerns over middle management agency prompted them to reframe the concept of a manager by using a set of managerial practices from the mining company CRA and the provisions of the Workplace Relations Act (1996) to individualise and deunionise their managerial ranks as a precursor to the deunionisation of the wider workforce.
Sacked! An investigation of young workers' dismissal
Authors: Kellner Ashlea , McDonald Paula , Waterhouse Jennifer
Published: April 2011

Limited academic attention has been afforded to young workers relative to their adult counterparts. This study addresses a phase of the employment relationship for young people that is very infrequently examined – during or around the time when the relationship ends. It examines the relative frequency of different forms of dismissal and the circumstances preceding the dismissals via a content analysis of 1259 cases of employee enquiries to a community advocacy organisation in Australia. Results indicate that dismissal was most commonly associated with bullying, harassment, and taking personal leave. Young men, compared to young women, were disproportionately likely to report allegations of misconduct as preceding dismissal, while females experienced higher rates of sexual harassment and discrimination. The research highlights the types and circumstances of dismissal across a range of employment contexts and reveals the complexities of youth employment relationships which may differ from those of the general workforce.
Mixed methods in business and management: A call to the ‘first generation’
Authors: Cameron Roslyn
Published: April 2011

Mixed methods is a youthful but increasingly robust methodological movement characterised by: a growing body of trans-disciplinary literature; prominent research methodologists/authorities; the emergence of mixed method specific journals, research texts, and courses; a growth in popularity amongst research funding bodies. Mixed methods is being utilised and reported within business and management fields, despite the quantitative traditions attached to certain business and management disciplines. This paper has utilised a multistrand conversion mixed model research design to undertake a retrospective content analysis of refereed papers (n = 281) from the 21st Australian and New Zealand Academy of Management (ANZAM) Conference 2007. The aim of the study is to provide a methodological map of the management research reported at the conference, and in particular the use, quality and acceptance level of mixed methods research within business and management fields. Implications for further research are discussed along with a call to the ‘first generation’ of business and management mixed method researchers to instigate mixed methods research training and capacity building within their respective business schools, relevant academies and associated professional forums and publications.
Digital Multiplexed Gene Expression Analysis Using the NanoString nCounter System
Authors: Kulkarni Meghana M.
Published: April 2011

This unit presents the protocol for the NanoString nCounter Gene Expression Assay, a robust and highly reproducible method for detecting the expression of up to 800 genes in a single reaction with high sensitivity and linearity across a broad range of expression levels. The methodology serves to bridge the gap between genome‐wide (microarrays) and targeted (real‐time quantitative PCR) expression profiling. The nCounter assay is based on direct digital detection of mRNA molecules of interest using target‐specific, color‐coded probe pairs. It does not require the conversion of mRNA to cDNA by reverse transcription or the amplification of the resulting cDNA by PCR. Each target gene of interest is detected using a pair of reporter and capture probes carrying 35‐ to 50‐base target‐specific sequences. In addition, each reporter probe carries a unique color code at the 5′ end that enables the molecular barcoding of the genes of interest, while the capture probes all carry a biotin label at the 3′ end that provides a molecular handle for attachment of target genes to facilitate downstream digital detection. After solution‐phase hybridization between target mRNA and reporter‐capture probe pairs, excess probes are removed and the probe/target complexes are aligned and immobilized in the nCounter cartridge, which is then placed in a digital analyzer for image acquisition and data processing. Hundreds of thousands of color codes designating mRNA targets of interest are directly imaged on the surface of the cartridge. The expression level of a gene is measured by counting the number of times the color‐coded barcode for that gene is detected, and the barcode counts are then tabulated. Curr. Protoc. Mol. Biol. 94:25B.10.1‐25B.10.17. © 2011 by John Wiley & Sons, Inc.
Risk factors for aortic valve disease in bicuspid aortic valve: A family‐based study
Authors: Calloway Troy J. , Martin Lisa J. , Zhang Xue , Tandon Animesh , Benson D. Woodrow , Hinton Robert B.
Published: April 2011

Bicuspid aortic valve (BAV) is the most common cardiovascular malformation and is a risk factor for aortic valve disease (AVD). AVD typically manifests later in life, and the majority of cases have BAV. The purpose of this study was to identify risk factors for AVD in individuals with BAV. Families enriched for BAV were identified in a pediatric population, and echocardiography was performed on all family members. AVD was identified as stenosis and/or insufficiency, and BAV morphology was defined as right–left (RL), right–non (RN) or indeterminate. Heritability (h2) of AVD and BAV morphology was estimated using variance components analysis (SOLAR). To assess AVD risk over time, we used Generalized Estimating Equations methodology (SAS) adjusting for age and gender. A total of 1,128 individuals from 226 families were evaluated. BAV was identified in 281 individuals (25%), and AVD was identified in 167 (59%) individuals with BAV. Previously, we identified a high heritability for BAV (h2 = 0.89 ± 0.06, P < 0.00001), but the heritability of AVD in the present study (0.07 ± 0.17, P = 0.33) was low. AVD was significantly associated with BAV morphology (P = 0.0027) and age (P = 0.0068). Children with RN BAV and adults with RL BAV were more likely to develop AVD. BAV is determined largely by genetic effects, but the phenotypic variability of AVD is primarily determined by nongenetic factors. BAV morphology may have predictive value for the time course of AVD. © 2011 Wiley‐Liss, Inc.
Visual threshold is set by linear and nonlinear mechanisms in the retina that mitigate noise
Authors: Pahlberg Johan , Sampath Alapakkam P.
Published: April 2011

In sensory biology, a major outstanding question is how sensory receptor cells minimize noise while maximizing signal to set the detection threshold. This optimization could be problematic because the origin of both the signals and the limiting noise in most sensory systems is believed to lie in stimulus transduction. Signal processing in receptor cells can improve the signal‐to‐noise ratio. However, neural circuits can further optimize the detection threshold by pooling signals from sensory receptor cells and processing them using a combination of linear and nonlinear filtering mechanisms. In the visual system, noise limiting light detection has been assumed to arise from stimulus transduction in rod photoreceptors. In this context, the evolutionary optimization of the signal‐to‐noise ratio in the retina has proven critical in allowing visual sensitivity to approach the limits set by the quantal nature of light. Here, we discuss how noise in the mammalian retina is mitigated to allow for highly sensitive night vision.
Interactive soft‐fabrics watering simulation on GPU
Authors: Huang Chen , Sun Hanqiu , Liu Shiguang , Li Ping
Published: April 2011

Physics‐based simulation is usually complex and time consuming, and consequently not suitable for real‐time applications. In this paper, we propose the efficient dynamics models for the real‐time simulation of soft fabrics interacting with water, including multi‐soaking effect and underwater dynamics. The multi‐soaking effect of soft fabrics is modeled based on the physics processes. Further, we develop the optimized mass–spring model that supports the large flow forces interacting with the fabrics underwater. The fabric spring forces are linearly derived and integrated with GPU–CUDA acceleration, feasible for real‐time VR applications with large set of fabric particles. Copyright © 2011 John Wiley & Sons, Ltd.
Paint‐on‐glass animation: the fellowship of digital paint and artisanal control
Authors: Van Laerhoven Tom , Di Fiore Fabian , Van Haevre William , Van Reeth Frank
Published: April 2011

In this paper we deal with paint‐on‐glass animation, which is a technique for making animated films by pushing slow‐drying paints from frame to frame directly under the camera. As artwork is continuously destroyed upon creating new frames, the animator is not able to rehearse or refine the animation afterwards. Furthermore, due to impracticable issues like how to stack up layers containing wet paint or how to overlay masks on the wet medium, one has to take both creative as technical decisions for each shot. Our approach consists of an interactive paint setup that physically simulates paint media. Together with a set of digital tools the artist is relieved from the difficult task of sustaining a constant frame‐to‐frame coherence while animating and is given the possibility to modify or undo earlier paint modifications. Regarding the interaction part, the artist stays in full control by employing a tangible interface. This allows artists to push pigment with their fingers, use special‐purpose digital brushes, or even to employ real life tools like paper tissue. Feedback from artists confirms the real‐life behaviour of stretching and smudging the paint as well as interacting with the setup, resulting in a natural and reality‐based methodology. Copyright © 2011 John Wiley & Sons, Ltd.
Experimental Apparatus for Studying Heat Transfer in Externally Heated Rotary Kilns
Authors: Thammavong P. , Debacq M. , Vitu S. , Dupoizat M.
Published: April 2011

Rotary kilns are widely used in several branches of the chemical industry. In order to control the temperature of the solid and the gas flowing through the kiln, it is important to understand the heat exchange phenomena that occur. The design and construction of a novel experimental device to study heat exchange in rotary kilns is described. The device, which comprises a rotary kiln equipped with an external electrical heating system, enables the study of the influence of various parameters such as the solid flow rate, the kiln inclination angle, the rotational speed, or the presence of lifters on heat exchange and in particular on the heat exchange coefficient between the solid and the wall. Preliminary experimental results concerning the influence of the solid flow rate and the rotational speed on the solid‐to‐wall heat exchange coefficient are presented.
Integration of Ultrafiltration Unit Operations in Biotechnology Process Design
Authors: Grote F. , Fröhlich H. , Strube J.
Published: April 2011

A stepwise process design approach is proposed to model membrane unit operations generally in combination with experimental model parameter determination in laboratory scale, in order to predict the purification performance a priori by simulations for multicomponent mixtures. The development of a rigorous model for an ultrafiltration membrane is described. In conceptual process design, the degree of comprehension of all unit operations integrated have to be almost identical to be able of any consistent process proposal taking equipment‐related fluid‐dynamical and kinetic nonidealities besides thermodynamical feasibility into account. Therefore, a process model, combining the most limiting factors within one mathematical model, is established and various filtrations are carried out with a binary solution for validation. Additionally, a standard laboratory equipment is instituted for logging time‐dependent concentration profiles. The practicability of the proposed procedure is proven in order to design and integrate ultrafiltration membranes into total purification processes.
Integrated Simulated Moving Bed Processes for Production of Single Enantiomers
Authors: Palacios J. G. , Kaspereit M. , Kienle A.
Published: April 2011

Based on the assumption of true moving bed processes it was demonstrated that integration of a racemization reaction into a continuous chromatographic process can improve the production of single enantiomers. In view of possible practical implementations, the analysis is extended to more realistic simulated moving bed (SMB) processes. Superstructures of SMB‐based systems are defined that reflect the three general concepts of flow sheet, partial, and total process integration. Process candidates are generated by simultaneously optimizing process structure and operating conditions. Optimal process setups are determined under idealized conditions as a function of the purity requirement. The best performance is achieved by fully integrated processes. These are compared under more realistic conditions to units with side reactors. The results indicate that a simple fully integrated SMB system with three zones is a particularly promising new process option. The new concept is investigated in detail to identify relevant practical aspects.
Reactions of Dimeric Aluminium Hydride Compounds Containing Bidentate Dianionic Pyrrolyl Ligands and Their Applications in Ring‐Opening Polymerization of ϵ‐Caprolactone
Authors: Chen Ya‐Chi , Lin Che‐Yu , Huang Wen‐Yen , Datta Amitabha , Huang Jui‐Hsien , Tsai Meng‐Shiue , Lee Ting‐Yu , Tu Cheng‐Yi , Hu Ching‐Han
Published: April 2011

A series of dimeric aluminium compounds containing substituted bidentate dianionic pyrrolyl ligands have been synthesized and their reactivity and application in the ring‐opening polymerization of ϵ‐caprolactone have been studied. The reactions of [{C4H3N(2‐CH2NtBu)}AlH]2 (1) with 2 equiv. of 1‐indanone and 9‐fluorenone in dichloromethane generated [{C4H3N(2‐CH2NtBu)}Al(μ‐OC9H9)]2 (2) and [{C4H3N(2‐CH2NtBu)}Al{μ‐OCH(C12H8)}]2 (3), respectively, by hydroalumination. Similarly, the reactions of 1 with 2 equiv. of 2‐cyclohexen‐1‐one, 1‐(2,4,6‐trimethylphenyl)‐1‐ethanone, benzophenone, and 1,1‐diphenylacetone in dichloromethane afforded NtBu‐bridged dialuminium compounds 4–7, [{C4H3N(2‐CH2NtBu)}Al(OR)]2 [4, R = C6H9; 5, R = CH(Me)(C6H2‐2,4,6‐Me3); 6, R = CHPh2; 7, R = CH(Me)(CHPh2)] by insertion. A similar insertion occurred when 1 was treated with 2 equiv. of 2,4‐pentandione and dibenzoylmethane in dichloromethane to yield NtBu‐bridged dioxylate aluminium dimeric compounds 8 and 9, respectively. The Al atoms in compounds 2 and 4–7 possess a distorted tetrahedral geometry whereas the Al atoms in 8 and 9 have a square‐pyramidal environment. All the compounds have been well characterized by NMR spectroscopy and compounds 2 and 4–9 in the solid state were subjected to X‐ray diffraction analysis. A study of the polymerization of ϵ‐caprolactone revealed that the activity of the Al complexes is largely reliant on the steric nature of the substituents of their alkoxide groups.
Development of a convection–diffusion–reaction model for solving Maxwell's equations in frequency domain
Authors: Sheu Tony W. H. , Lin K. C. , Li J. H.
Published: April 2011

We propose in this study a numerically accurate and computationally efficient convection–diffusion–reaction finite difference scheme to discretize the full‐vector and semi‐vector optical waveguide equations. The scheme formulated in a grid stencil of five nodal points for solving the three‐dimensional waveguide equations employs the locally analytic solution. In this three‐dimensional study, calculations were carried out for the investigation of wave propagation in diffused channel, rectangular and rib types of optical waveguide. Copyright © 2011 John Wiley & Sons, Ltd.
Prediction from the One‐Way Error Components Model with AR(1) Disturbances
Authors: Kouassi Eugene , Sango Joel , Bosson Brou J.M. , Teubissi Francis N. , Kymn Kern O.
Published: April 2011

In this paper we extend the works of Baillie and Baltagi (1999, in Analysis of Panels and Limited Dependent Variables Models, Hsiao C et al. (eds). Cambridge University Press: Cambridge, UK; 255–267) and generalize certain results from the Baltagi and Li (1992, Journal of Forecasting 11: 561–567) paper accounting for AR(1) errors in the disturbance term. In particular, we derive six predictors for the one‐way error components model, as well as their associated asymptotic mean squared error of multi‐step prediction in the presence of AR(1) errors in the disturbance term. In addition, we also provide both theoretical and simulation evidence as to the relative efficiency of our alternative predictors. The adequacy of the prediction AMSE formula is also investigated by the use of Monte Carlo methods and indicates that the ordinary optimal predictor performs well for various accuracy criteria. Copyright © 2011 John Wiley & Sons, Ltd.
Structural trends in TeI2RR′: Crystal structures and NMR spectra of TeI2(CH2SiMe3)2, TeI2Th(CH2SiMe3), TeI2Ph(CH2SiMe3), and TeI2Th2 (Th = 2‐Thienyl, C4H3S)
Authors: Poropudas Merja J. , Vigo Ludmila , Oilunkaniemi Raija , Laitinen Risto S.
Published: April 2011

TeI2(CH2SiMe3)2(1), TeI2Th(CH2SiMe3 (2), TeI2Ph(CH2SiMe3)(3), and TeI2Th2(4) (Th = 2‐thienyl) were synthesized in excellent yields from the corresponding tellanes and I2. The products were characterized by 125Te NMR spectroscopy and single crystal X‐ray crystallography. Each TeI2RR′ molecule shows a trigonal bipyramidal coordination around tellurium with the iodine atoms occupying axial positions, and the organic groups and the lone pair occupying equatorial positions. The TeI bonds and the ITeI angles in 1–4 span a range of 2.8407(9)–3.0194(10) Å and 171.85(2)–175.71(2)°, respectively. The TeC bonds and CTeC angles show respective ranges of 2.100(6)–2.136(7) Å and 95.1(3)–100.9(3)°. In the solid state, the molecules show a varying degree of secondary bonding interactions. With the exception of TeI2(CH2SiMe3)2 (1), the compounds show Te···I or I···I secondary bonding interactions leading to supramolecular assemblies. TeI2Ph(CH2SiMe3) crystallizes as two polymorphs. One (3a) is isomorphic with TeI2Th(CH2SiMe3) (2). The other (3b) shows a lattice of two alternating layers of molecules. In one layer, the molecules are linked into a two‐dimensional network by Te···I and I···I interactions whereas the second layer consists of discrete dimers. The strongest Te···I secondary bonding interactions are observed for TeI2Th2. The lattice is composed of tetramers that is reminiscent of those in γ‐ and δ‐TeI4 and also have precedent in TeI2RR′ species. The structures of TeI2Me2 and TeI2Ph2 have been considered for comparison. The trends in 125Te NMR chemical shifts in TeI2RR′ (R, R′ = Me, CH2SiMe3, Th, Ph) are also discussed. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:348–357, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20688