bluuebunny/crossref_metadata_2025_split huggingface dataset:
The asymmetry of telomere replication contributes to replicative senescence heterogeneity
Authors: Bourgeron Thibault , Xu Zhou , Doumic Marie , Teixeira Maria Teresa 
Published: October 2015

AbstractIn eukaryotes, the absence of telomerase results in telomere shortening, eventually leading to replicative senescence, an arrested state that prevents further cell divisions. While replicative senescence is mainly controlled by telomere length, the heterogeneity of its onset is not well understood. This study proposes a mathematical model based on the molecular mechanisms of telomere replication and shortening to decipher the causes of this heterogeneity. Using simulations fitted on experimental data obtained from individual lineages of senescent Saccharomyces cerevisiae cells, we decompose the sources of senescence heterogeneity into interclonal and intraclonal components and show that the latter is based on the asymmetry of the telomere replication mechanism. We also evidence telomere rank-switching events with distinct frequencies in short-lived versus long-lived lineages, revealing that telomere shortening dynamics display important variations. Thus, the intrinsic heterogeneity of replicative senescence and its consequences find their roots in the asymmetric structure of telomeres.
A dark green fluorescent protein as an acceptor for measurement of Förster resonance energy transfer
Authors: Murakoshi Hideji , Shibata Akihiro C. E. , Nakahata Yoshihisa , Nabekura Junichi 
Published: October 2015

AbstractMeasurement of Förster resonance energy transfer by fluorescence lifetime imaging microscopy (FLIM-FRET) is a powerful method for visualization of intracellular signaling activities such as protein-protein interactions and conformational changes of proteins. Here, we developed a dark green fluorescent protein (ShadowG) that can serve as an acceptor for FLIM-FRET. ShadowG is spectrally similar to monomeric enhanced green fluorescent protein (mEGFP) and has a 120-fold smaller quantum yield. When FRET from mEGFP to ShadowG was measured using an mEGFP-ShadowG tandem construct with 2-photon FLIM-FRET, we observed a strong FRET signal with low cell-to-cell variability. Furthermore, ShadowG was applied to a single-molecule FRET sensor to monitor a conformational change of CaMKII and of the light oxygen voltage (LOV) domain in HeLa cells. These sensors showed reduced cell-to-cell variability of both the basal fluorescence lifetime and response signal. In contrast to mCherry- or dark-YFP-based sensors, our sensor allowed for precise measurement of individual cell responses. When ShadowG was applied to a separate-type Ras FRET sensor, it showed a greater response signal than did the mCherry-based sensor. Furthermore, Ras activation and translocation of its effector ERK2 into the nucleus could be observed simultaneously. Thus, ShadowG is a promising FLIM-FRET acceptor.
Optical design of nanowire absorbers for wavelength selective photodetectors
Authors: Mokkapati S. , Saxena D. , Tan H. H. , Jagadish C. 
Published: October 2015

AbstractWe propose the optical design for the absorptive element of photodetectors to achieve wavelength selective photo response based on resonant guided modes supported in semiconductor nanowires. We show that the waveguiding properties of nanowires result in very high absorption efficiency that can be exploited to reduce the volume of active semiconductor compared to planar photodetectors, without compromising the photocurrent. We present a design based on a group of nanowires with varying diameter for multi-color photodetectors with small footprint. We discuss the effect of a dielectric shell around the nanowires on the absorption efficiency and present a simple approach to optimize the nanowire diameter-dielectric shell thickness for maximizing the absorption efficiency.
The HIV matrix protein p17 induces hepatic lipid accumulation via modulation of nuclear receptor transcriptoma
Authors: Renga Barbara , Francisci Daniela , Carino Adriana , Marchianò Silvia , Cipriani Sabrina , Chiara Monti Maria , Del Sordo Rachele , Schiaroli Elisabetta , Distrutti Eleonora , Baldelli Franco , Fiorucci Stefano 
Published: October 2015

AbstractLiver disease is the second most common cause of mortality in HIV-infected persons. Exactly how HIV infection per se affects liver disease progression is unknown. Here we have investigated mRNA expression of 49 nuclear hormone receptors (NRs) and 35 transcriptional coregulators in HepG2 cells upon stimulation with the HIV matrix protein p17. This viral protein regulated mRNA expression of some NRs among which LXRα and its transcriptional co-activator MED1 were highly induced at mRNA level. Dissection of p17 downstream intracellular pathway demonstrated that p17 mediated activation of Jak/STAT signaling is responsible for the promoter dependent activation of LXR. The treatment of both HepG2 as well as primary hepatocytes with HIV p17 results in the transcriptional activation of LXR target genes (SREBP1c and FAS) and lipid accumulation. These effects are lost in HepG2 cells pre-incubated with a serum from HIV positive person who underwent a vaccination with a p17 peptide as well as in HepG2 cells pre-incubated with the natural LXR antagonist gymnestrogenin. These results suggest that HIV p17 affects NRs and their related signal transduction thus contributing to the progression of liver disease in HIV infected patients.
Hybrid OFDM experimentation based on arrayed waveguide grating for all‐optical FFT implementation in PON architecture
Authors: Morosi J. , Boffi P. , Martelli P. , Parolari P. , Cincotti G. , Shimizu S. , Wada N. 
Published: October 2015

A hybrid optical frequency division multiplexing (OFDM) system based on the electrical generation of the OFDM signal at the transmitter and on the all‐optical demultiplexing of the OFDM subcarriers is experimentally demonstrated by exploiting a purposely designed arrayed waveguide grating (AWG) with 12.5 GHz frequency spacing. The AWG passively and all‐optically processes a 3‐subcarrier OFDM signal with fast Fourier transform functionalities, demultiplexing it into three 12.5 Gbit/s on–off keyed data at the corresponding output ports, which are then connected to the optical network users. Transmission over a 40 km feeder link is experimentally demonstrated. Taking into account the AWG's available 16 ports and four 3‐subcarrier OFDM signal generators modulating independent wavelength carriers, a passive optical network (PON) architecture can be realised serving 12 optical network units with 150 Gbit/s total aggregate downstream capacity.
Modeling of fast neutral-beam-generated ions and rotation effects on RWM stability in DIII-D plasmas
Authors: Turco F. , Turnbull A. D. , Hanson J. M. , Navratil G. A. 
Published: October 2015

Abstract
Validation results for the MARS-K (Liu et al 2008 Phys. Plasmas
15 112503) code for DIII-D equilibria, predict that the absence of fast Neutral Beam (NB) generated ions leads to a plasma response ~40–60% higher than in NB-sustained H-mode plasmas when the no-wall β
N limit is reached. In a β
N scan, the MARS-K model with thermal and fast-ions, reproduces the experimental measurements above the no-wall limit, except at the highest β
N where the phase of the plasma response is overestimated. The dependencies extrapolate unfavourably to machines such as ITER with smaller fast ion fractions since elevated responses in the absence of fast ions indicate the potential onset of a resistive wall mode (RWM). The model was also tested for the effects of rotation at high β
N, and recovers the measured response even when fast-ions are neglected, reversing the effect found in lower β
N cases, but consistent with the higher β
N results above the no-wall limit. The agreement in the response amplitude and phase for the rotation scan is not as good, and additional work will be needed to reproduce the experimental trends. In the case of current-driven instabilities, the magnetohydrodynamic spectroscopy system used to measure the plasma response reacts differently from that for pressure driven instabilities: the response amplitude remains low up to ~93% of the current limit, showing an abrupt increase only in the last ~5% of the current ramp. This makes it much less effective as a diagnostic for the approach to an ideal limit. However, the mode structure of the current driven RWM extends radially inwards, consistent with that in the pressure driven case for plasmas with q
edge~2. This suggests that previously developed RWM feedback techniques together with the additional optimizations that enabled q
edge~2 operation, can be applied to control of both current-driven and pressure-driven modes at high β
N.
FCGR2A and FCGR3A Genotypes in Human Immunodeficiency Virus Mother-to-Child Transmission
Authors: Milligan Caitlin , Richardson Barbra A. , John-Stewart Grace , Nduati Ruth , Overbaugh Julie 
Published: October 2015

AbstractBackground.  Fc-mediated effector functions have been suggested to influence human immunodeficiency virus (HIV) acquisition and disease progression. Analyzing the role of host Fc gamma receptor (FcγR) polymorphisms on HIV outcome in mother-to-child transmission (MTCT) will increase our understanding of how host genetics may alter immune responses in prevention, therapy, and disease. This study analyzed the impact of FCGR2A and FCGR3A genotypes on MTCT in a cohort in which Fc-mediated antibody functions are predictive of infant HIV outcome.Methods.  Human immunodeficiency virus-positive mothers and their infants from a historical MTCT cohort were genotyped for FCGR2A and FCGR3A. We assessed the impact of these genotypes on transmission and acquisition of HIV and disease progression using χ2 tests, survival analyses, and logistic regression.Results.  Among 379 mother-infant pairs, infant FCGR2A and FCGR3A genotypes were not associated with infant HIV infection or disease progression. Maternal FCGR2A was not associated with transmission, but there was a trend between maternal FCGR3A genotype and transmission (P = .07). When dichotomizing mothers into FCGR3A homozygotes and heterozygotes, heterozygotes had a 64.5% higher risk of transmission compared with homozygotes (P = .02). This risk was most evident in the early breastfeeding window, but a trend was only observed when restricting analyses to breastfeeding mothers (hazards ratio, 1.64; P = .064).Conclusions.  Infant FCGR2A and FCGR3A genotypes were not associated with HIV infection or disease progression, and, thus, host FcγR genotype may not significantly impact vaccination or therapeutic regimens that depend on Fc-mediated antibody functions. Maternal FCGR3A genotype may influence early breastfeeding transmission risk, but more studies should be conducted to clarify this association and its mechanism.
Multi-Unit Activity contains information about spatial stimulus structure in mouse primary visual cortex
Authors: Tolkiehn Marie , Schultz Simon R. 
Published: October 2015

AbstractThis study investigates the spatial and directional tuning of Multi-Unit Activity (MUA) in mouse primary visual cortex and how MUA can reflect spatiotemporal structures contained in moving gratings. Analysis of multi-shank laminar electrophysiological recordings from mouse primary visual cortex indicates a directional preference for moving gratings around 180°, while preferred spatial frequency peaks around 0.02 cycles per degree, which is similar as reported in single-unit studies. Using only features from MUA, we further achieved a significant performance in decoding spatial frequency or direction of moving gratings, with average decoding performances of up to 58.54% for 8 directions, and 44% correctly identified spatial frequencies against chance level of 16.7%.
Spike Detection Using FRI Methods and Protein Calcium Sensors: Performance Analysis and Comparisons
Authors: Reynolds Stephanie , Oñativia Jon , Copeland Caroline S , Schultz Simon R , Dragotti Pier Luigi 
Published: October 2015

AbstractFast and accurate detection of action potentials from neurophysiological data is key to the study of information processing in the nervous system. Previous work has shown that finite rate of innovation (FRI) theory can be used to successfully reconstruct spike trains from noisy calcium imaging data. This is due to the fact that calcium imaging data can be modeled as streams of decaying exponentials which are a subclass of FRI signals. Recent progress in the development of genetically encoded calcium indicators (GECIs) has produced protein calcium sensors that exceed the sensitivity of the synthetic dyes traditionally used in calcium imaging experiments. In this paper, we compare the suitability for spike detection of the kinetics of a new family of GECIs (the GCaMP6 family) with the synthetic dye Oregon Green BAPTA-1. We demonstrate the high performance of the FRI algorithm on surrogate data for each calcium indicator and we calculate the Cramér-Rao lower bound on the uncertainty of the position of a detected spike in calcium imaging data for each calcium indicator.
A contextual approach to supply chain risk mitigation
Authors: Chang Woojung , Ellinger Alexander E. , Blackhurst Jennifer 
Published: October 2015

Purpose– As global supply networks proliferate, the strategic significance of supply chain risk management (SCRM) – defined as the identification, evaluation, and management of supply chain-related risks to reduce overall supply chain vulnerability – also increases. Yet, despite consistent evidence that firm performance is enhanced by appropriate fit between strategy and context, extant SCRM research focusses more on identifying sources of supply chain risk, types of SCRM strategy, and performance implications associated with SCRM than on the relative efficacy of alternative primary supply chain risk mitigation strategies in different risk contexts. Drawing on contingency theory, a conceptual framework is proposed that aligns well-established aspects of SCRM to present a rubric for matching primary alternative supply chain risk mitigation strategies (redundancy and flexibility) with particular risk contexts (severity and probability of risk occurrence). The paper aims to discuss these issues.Design/methodology/approach– Conceptual paper.Findings– The proposed framework addresses supply chain managers’ need for a basic rubric to help them choose and implement risk mitigation approaches. The framework may also prove helpful for introducing business students to the fundamentals of SCRM.Originality/value– The framework and associated research propositions provide a theoretically grounded basis for managing the firm’s portfolio of potential supply chain risks by applying appropriate primary risk mitigation strategies based on the specific context of each risk rather than taking a “one size fits all” approach to risk mitigation. An agenda for progressing research on contingency-based approaches to SCRM is also presented.
Cloud computing, Web 2.0, and operational performance
Authors: Bruque Cámara Sebastián , Moyano Fuentes José , Maqueira Marín Juan Manuel 
Published: October 2015

Purpose– The purpose of this paper is to analyze the effects of two technologies, cloud computing and Web 2.0, on a firm’s operational performance, examining the relationship between these two technologies and operational performance, and the mediating role played by supply chain integration.Design/methodology/approach– A random sample of 394 companies taken from the DUNS 50,000 database in Spain is used to test the paper’s hypotheses. The data were gathered by telephone survey using the CATI computerized system to manage interviewees’ answers, obtaining a 19.36 percent response rate. Factorial analyses and structural equation modeling were used to test the hypotheses.Findings– The results suggest that cloud computing requires the mediating support of supply chain integration. However, there is no concluding evidence that Web 2.0 has a positive effect on either supply chain integration or operational performance. A positive, significant relationship was found between supply chain integration and operational performance in all the models used.Research limitations/implications– Further research and longitudinal analyses should be carried out in a range of industrial and geographical settings to confirm the findings of this study. Further analyses could also extend the scope and generalizability of results by analyzing the assimilation of supply chain integration-related inter-organizational information systems, such as the effect of ERP systems on performance. Another future direction for research is a study of the impact of the joint assimilation of internal and external integration practices on operational performance.Practical implications– Managers should be aware of the key role that trust plays in the information-sharing process in conjunction with supply chain management. Trust and information-sharing are two inextricably linked elements that enable greater supply chain integration to translate into better operational performance. This paper can also make managers more aware of the powerful tools that exist in the cloud computing universe and those that come under the umbrella of Web 2.0. Companies can use the findings of this paper to create new applications to facilitate supply chain integration. Some examples are also given of how cloud applications can be applied to better integrate the supply chain and, ultimately, to improve overall operational performance.Originality/value– This is one of the first attempts to disentangle the effects exerted by cloud computing on company performance through the mediating role of a higher supply chain integration. The value of this study relies in that academics and practitioners may have a supporting evidence on the role played by a new, disruptive technology such us cloud computing in, internal, operationally linked structures such as supply chain integration and how this combination transforms into better operational outcomes.
An empirical examination of the determinants of trust in Ghana
Authors: Sulemana Iddisah , Issifu Ibrahim 
Published: October 2015

Purpose– How trust affects political, social, and economic phenomena have been studied by scholars for many years. However, not many studies have examined what factors determine trust among people and trust in public institutions. There is particularly a dearth of research on trust in Ghana. The paper aims to discuss this issue.Design/methodology/approach– The authors use data from the 2012 Afrobarometer Surveys to mimic four sets of variables that Alesina and La Ferrara (2002) find as significant determinants of trust – recent traumatic experiences, having been historically discriminated against, being economically unsuccessful, and living in a mixed community. The authors apply these variables to the Ghanaian context to explore how they affect generalized trust, trust in relatives, neighbors, and other people the respondent knows, as well as trust in six public institutions (i.e. The President, Parliament, Electoral Commission, Police, Army, and the Courts of Law).Findings– The authors find that trust among Ghanaians is generally low. Women are significantly less trusting of public institutions, although they do not trust people (e.g. relatives, neighbors, etc.) any less than men. Both people of the North and South are generally less trusting of public institutions compared to people of the Volta Region. The authors also find that, to a large extent, satisfaction with democracy and political affiliation are significantly correlated with trust in public institutions.Practical implications– Because trust is very crucial for political, economic, and social development, especially good governance, there is an urgent need for public policy interventions that could increase trust among Ghanaians.Originality/value– The authors provide a Ghanaian perspective on the determinants of trust.
Empowering front office employees with counseling affordances
Authors: Giesbrecht Tobias , Schenk Birgit , Schwabe Gerhard 
Published: October 2015

Purpose– The purpose of this paper is to investigate the face-to-face citizen service encounter in public administrations’ front offices, and present a novel qualification approach to empower service personnel on-the-job, and thereby deepen the knowledge on the role of information and communication technology for advancing governmental reforms.Design/methodology/approach– The presented study follows a design science research methodology, conducted in collaboration with the public administration of a major German city. Data were collected using multiple quantitative and qualitative methods, including questionnaires, semi-structured interviews and video analysis.Findings– A novel on-the-job qualification approach for empowering public employees in their job-related skills, building on the concept of affordances, is developed. Thereto, six design principles for equipping artifacts with counseling affordances are presented. Evaluations in real-world environments provide first evidence that “learning with counseling affordances” constitutes an effective qualification measure to initiate experiential learning on-the-job, helping employees in the resource-restricted work environment of public front offices to obtain the skills to provide superior advisory services.Research limitations/implications– The “learning with counseling affordances” approach was developed in collaboration with an individual major German city and the paper provides first evidence of its effectiveness and suitability. Hence, the study’s insights should be approved by further research to strengthen generalizability.Originality/value– The paper highlights the previously neglected aspects of employee’s skills and qualification for promoting governmental transformation. By highlighting the beneficial relationship between affordances and on-the-job learning, the paper provides novel insights on the role of information and communication technology to promote governmental transformation.
Rural realities
Authors: Freeman Julie , Park Sora 
Published: October 2015

Purpose– This article explores challenges for rural Australian local governments during the transition to high-speed broadband infrastructure. Despite the National Broadband Network’s promised ubiquitous connectivity, significant access discrepancies remain between rural and urban areas.Design/methodology/approach– Empirical findings are drawn from a full-day workshop on digital connectivity, which included participants from seven rural local governments in New South Wales, Australia. Thematic analysis of the workshop transcript was undertaken to extrapolate recurring nuances of rural digital exclusion.Findings– Rural communities face inequitable prospects for digital inclusion, and authorities confront dual issues of accommodating connected and unconnected citizens. Many areas have no or poor broadband access, and different digital engagement expectations are held by citizens and local governments. Citizens seek interactive opportunities, but rural authorities often lack the necessary resources to offer advanced participatory practices.Research limitations/implications– While this research draws from a small sample of government officials, their insights are, nonetheless, heuristically valuable in identifying connectivity issues faced in rural Australia. These issues can guide further research into other regions as well as civic experiences of digital inclusion.Practical implications– There is a need to reconceive Australia’s current policy approach to broadband. Greater rural digital inclusion may be achieved by focusing on connectivity as a public interest goal, targeting infrastructure developments to suit local contexts and implementing participatory digital government practices.Originality/value– The actions suggested would help ensure equity of digital inclusion across Australian municipal areas. Without such changes, there is a risk of rural citizens facing further marginalisation through digital exclusion.