bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Online Simulation Technique for Revenue-Based Value for Money Assessment Model in PPP Project
Authors: Peng Wei , Liu Honglei
Published: July 2013

Infrastructure public private partnerships (PPP) procurement must be carefully selected on the basis of value for money when compared to conventional procurement. While the value for money analysis has been widely used to ensure low procurement cost in PPP, little is known with respect to its effectiveness and data source. The paper explores existing value for money assessment model and reports its deficiencies in ignoring project revenue and network data collecting. Addressing the current issues, a new revenue based value for money assessment model with Monte Carlo simulation technique is proposed. Data used for simulation come from project participants who obtain and share data through an online virtual collaborative platform. By applying this online technique, project data is more easily shared and reused. This data transmission process is automated and seamless. Then, the effectiveness of new model was examined by using a hypothetical toll road case. It shows that the new value for money assessment model demonstrates the significant advantage in estimating the risk, cost, and revenue variance and assisting the public agency to make decision in the procurement phase.
Simulation of Improved Fourth-Order Colpitts Oscillator
Authors: Qiao Xiaohua , Sun Yuxia , Zhang Hongqin , Xu Yaping
Published: July 2013

A RLC parallel resonance circuit was built on the basis of the original fourth-order Colpitts oscillator. An improved Colpitts oscillator was given. The Lyapunov exponent spectrum, bifurcation diagram and phase trajectories of chaotic attractors were calculated by control theory and numerical methods. Analysis shows that the change of resistance value R of the RLC parallel resonance circuit to control Colpitts oscillator can obtain better dynamic characteristics than the original fourth-order Colpitts oscillator, and the control circuit implementation is very simple. More interestingly, it is found that the bifurcation behavior of the new system has the Fengenbaum first constant in the logarithm law. The experimental circuit of the new system was designed. The experimental results and theoretical analysis have a good consistency, indicating that this control scheme is of feasibility and better practicability.
A Systematic Literature Review on Usability Heuristics for Mobile Phones
Authors: Salazar Luiz Henrique A. , Lacerda Thaísa , Nunes Juliane Vargas , Gresse von Wangenheim Christiane
Published: July 2013

For the last decade, mobile phones have been the fastest growing segment of the technology market increasing the importance of interface design for this type of device. Yet, many of the assumptions about user interactions that the authors know from “traditional” computer usage do not hold true for mobile devices and more specifically for touch-screen phones. A key question is, if usability heuristics tailored to this type of device exist. To answer this question, they conducted a systematic literature review. The authors analyzed the encountered sets of heuristics by mapping them to Nielsen’s ten heuristics and identified additional ones specifically proposed for this kind of device. Their review indicates that research findings with respect to usability heuristics for mobile phones are still extreme sparse. Most of these heuristics are strongly based on “traditional” ones, not considering comprehensively mobile phone characteristics concerning physical limitations, technology, usage goals, features as well as user characteristics and usage environment. Nevertheless, this article provides a general overview on the state of the art of usability heuristics for mobile phones. This can guide the design and evaluation interfaces for mobile phones as well as provide a starting point for the evolution of such heuristics taking into consideration more extensively the specific features of mobile phones.
Participant Experiences of Mobile Device-Based Diary Studies
Authors: Sun Xu , Golightly David , Cranwell Jo , Bedwell Benjamin , Sharples Sarah
Published: July 2013

Mobile device-based diary studies have potential as contextual data capture methods that address the limitations of the traditional paper-based diary method. While there have been a number of studies that demonstrate the power of the mobile device-based diary approach, there is less known about participants’ experience of such studies. This paper presents three cases of mobile data capture to bring together user experiences of participating in diary studies and discuss how this can be fed into the design of methodology.
An Empirical Comparison of Machine Learning Techniques in Predicting the Bug Severity of Open and Closed Source Projects
Authors: Chaturvedi K. K. , Singh V.B.
Published: July 2013

Bug severity is the degree of impact that a defect has on the development or operation of a component or system, and can be classified into different levels based on their impact on the system. Identification of severity level can be useful for bug triager in allocating the bug to the concerned bug fixer. Various researchers have attempted text mining techniques in predicting the severity of bugs, detection of duplicate bug reports and assignment of bugs to suitable fixer for its fix. In this paper, an attempt has been made to compare the performance of different machine learning techniques namely Support vector machine (SVM), probability based Naïve Bayes (NB), Decision Tree based J48 (A Java implementation of C4.5), rule based Repeated Incremental Pruning to Produce Error Reduction (RIPPER) and Random Forests (RF) learners in predicting the severity level (1 to 5) of a reported bug by analyzing the summary or short description of the bug reports. The bug report data has been taken from NASA’s PITS (Projects and Issue Tracking System) datasets as closed source and components of Eclipse, Mozilla & GNOME datasets as open source projects. The analysis has been carried out in RapidMiner and STATISTICA data mining tools. The authors measured the performance of different machine learning techniques by considering (i) the value of accuracy and F-Measure for all severity level and (ii) number of best cases at different threshold level of accuracy and F-Measure.
SARP: A Novel Algorithm to Assess Compositional Biases in Protein Sequences
Authors: Antonets Kirill S. , Nizhnikov Anton A.
Published: July 2013

The composition of a defined set of subunits (nucleotides, amino acids) is one of the key features of biological sequences. Compositional biases are local shifts in amino acid or nucleotide frequencies that can occur as an adaptation of an organism to an extreme ecological niche, or as the signature of a specific function or localization of the corresponding protein. The calculation of probability is a method for annotating compositional bias and providing accurate detection of biased subsequences. Here, we present a Sequence Analysis based on the Ranking of Probabilities (SARP), a novel algorithm for the annotation of compositional biases based on ranking subsequences by their probabilities. SARP provides the same accuracy as the previously published Lower Probability Subsequences (LPS) algorithm but performs at an approximately 230-fold faster rate. It can be recommended for use when working with large datasets to reduce the time and resources required.
Averaging kernel prediction from atmospheric and surface state parameters based on multiple regression for nadir-viewing satellite measurements of carbon monoxide and ozone
Authors: Worden H. M. , Edwards D. P. , Deeter M. N. , Fu D. , Kulawik S. S. , Worden J. R. , Arellano A.
Published: July 2013

Abstract. A current obstacle to the observation system simulation experiments (OSSEs) used to quantify the potential performance of future atmospheric composition remote sensing systems is a computationally efficient method to define the scene-dependent vertical sensitivity of measurements as expressed by the retrieval averaging kernels (AKs). We present a method for the efficient prediction of AKs for multispectral retrievals of carbon monoxide (CO) and ozone (O3) based on actual retrievals from MOPITT (Measurements Of Pollution In The Troposphere) on the Earth Observing System (EOS)-Terra satellite and TES (Tropospheric Emission Spectrometer) and OMI (Ozone Monitoring Instrument) on EOS-Aura, respectively. This employs a multiple regression approach for deriving scene-dependent AKs using predictors based on state parameters such as the thermal contrast between the surface and lower atmospheric layers, trace gas volume mixing ratios (VMRs), solar zenith angle, water vapor amount, etc. We first compute the singular value decomposition (SVD) for individual cloud-free AKs and retain the first three ranked singular vectors in order to fit the most significant orthogonal components of the AK in the subsequent multiple regression on a training set of retrieval cases. The resulting fit coefficients are applied to the predictors from a different test set of test retrievals cased to reconstruct predicted AKs, which can then be evaluated against the true retrieval AKs from the test set. By comparing the VMR profile adjustment resulting from the use of the predicted vs. true AKs, we quantify the CO and O3 VMR profile errors associated with the use of the predicted AKs compared to the true AKs that might be obtained from a computationally expensive full retrieval calculation as part of an OSSE. Similarly, we estimate the errors in CO and O3 VMRs from using a single regional average AK to represent all retrievals, which has been a common approximation in chemical OSSEs performed to date. For both CO and O3 in the lower troposphere, we find a significant reduction in error when using the predicted AKs as compared to a single average AK. This study examined data from the continental United States (CONUS) for 2006, but the approach could be applied to other regions and times.
The impact of extreme summer drought on the short-term carbon coupling of photosynthesis to soil CO2 efflux in a temperate grassland
Authors: Burri S. , Sturm P. , Prechsl U. E. , Knohl A. , Buchmann N.
Published: July 2013

Abstract. Along with predicted climate change, increased risks for summer drought are projected for Central Europe. However, large knowledge gaps exist in terms of how drought events influence the short-term ecosystem carbon cycle. Here, we present results from 13CO2 pulse labeling experiments at an intensively managed lowland grassland in Switzerland. We investigated the effect of extreme summer drought on the short-term coupling of freshly assimilated photosynthates in shoots to roots as well as to soil CO2 efflux. Summer drought was simulated using rainout shelters during two field seasons (2010 and 2011). Soil CO2 efflux and its isotopic composition were measured with custom-built chambers coupled to a quantum cascade laser spectrometer (QCLAS-ISO, Aerodyne Research Inc., MA, USA). During the 90 min pulse labeling experiments, we added 99.9 atom % 13CO2 to the grass sward. In addition to the isotopic analysis of soil CO2 efflux, this label was traced over 31 days into bulk shoots, roots and soil. Drought reduced the incorporation of recently fixed carbon into shoots and increased carbon allocation below-ground relative to total tracer uptake. Contrary to our hypothesis, we did not find a change in allocation speed in response to drought, although drought clearly reduced soil CO2 efflux rates. 19 days after pulse labeling, only about 60% of total tracer uptake was lost via soil CO2 efflux under drought compared to about 75% under control conditions. Predisposition of grassland by spring drought lead to different responses to summer drought in 2011 compared to 2010, suggesting increased sensitivity of grassland to consecutive drought events as predicted under future climate change.
Spatial distribution of stable water isotopes in alpine snow cover
Authors: Dietermann N. , Weiler M.
Published: July 2013

Abstract. The aim of this study was to analyse and predict the mean stable water isotopic composition of the snow cover at specific geographic locations and altitudes. In addition, the dependence of the isotopic composition of the entire snow cover on altitude was analysed. Snow in four Swiss catchments was sampled at the end of the accumulation period in April 2010 and a second time during snowmelt in May 2010 and analysed for stable isotope composition of 2H and 18O. The sampling was conducted at both south-facing and north-facing slopes at elevation differences of 100 m, for a total altitude difference of approximately 1000 m. The observed variability of isotopic composition of the snow cover was analysed with stepwise multiple linear regression models. The analysis indicated that there is only a limited altitude effect on the isotopic composition when considering all samples. This is due to the high variability of the isotopic composition of the precipitation during the winter months and, in particular in the case of south-facing slopes, an enrichment of heavy isotopes due to intermittent melting processes. This enrichment effect could clearly be observed in the samples which were taken later in the year. A small altitudinal gradient of the isotopic composition could only be observed at some north-facing slopes. However, the dependence of snow depth and the day of the year were significant predictor variables in all models. This study indicates the necessity to further study the variability of water isotopes in the snow cover to increase prediction for isotopic composition of snowmelt and hence increase model performance of residence time models for alpine areas in order to better understand the accumulation processes and the sources of water in the snow cover of high mountains.
Assessing the predictive capability of randomized tree-based ensembles in streamflow modelling
Authors: Galelli S. , Castelletti A.
Published: July 2013

Abstract. Combining randomization methods with ensemble prediction is emerging as an effective option to balance accuracy and computational efficiency in data-driven modelling. In this paper, we investigate the prediction capability of extremely randomized trees (Extra-Trees), in terms of accuracy, explanation ability and computational efficiency, in a streamflow modelling exercise. Extra-Trees are a totally randomized tree-based ensemble method that (i) alleviates the poor generalisation property and tendency to overfitting of traditional standalone decision trees (e.g. CART); (ii) is computationally efficient; and, (iii) allows to infer the relative importance of the input variables, which might help in the ex-post physical interpretation of the model. The Extra-Trees potential is analysed on two real-world case studies – Marina catchment (Singapore) and Canning River (Western Australia) – representing two different morphoclimatic contexts. The evaluation is performed against other tree-based methods (CART and M5) and parametric data-driven approaches (ANNs and multiple linear regression). Results show that Extra-Trees perform comparatively well to the best of the benchmarks (i.e. M5) in both the watersheds, while outperforming the other approaches in terms of computational requirement when adopted on large datasets. In addition, the ranking of the input variable provided can be given a physically meaningful interpretation.
Regionalization of patterns of flow intermittence from gauging station records
Authors: Snelder T. H. , Datry T. , Lamouroux N. , Larned S. T. , Sauquet E. , Pella H. , Catalogne C.
Published: July 2013

Abstract. Understanding large-scale patterns in flow intermittence is important for effective river management. The duration and frequency of zero-flow periods are associated with the ecological characteristics of rivers and have important implications for water resources management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times series describing flow intermittence; the frequency of zero-flow periods (consecutive days of zero flow) in each year of record (FREQ; yr−1), and the total number of zero-flow days in each year of record (DUR; days). These time series were used to calculate two indices for each station, the mean annual frequency of zero-flow periods (mFREQ; yr−1), and the mean duration of zero-flow periods (mDUR; days). Approximately 20% of stations had recorded at least one zero-flow period in their record. Dissimilarities between pairs of gauges calculated from the annual times series (FREQ and DUR) and geographic distances were weakly correlated, indicating that there was little spatial synchronization of zero flow. A flow-regime classification for the gauging stations discriminated intermittent and perennial stations, and an intermittence classification grouped intermittent stations into three classes based on the values of mFREQ and mDUR. We used random forest (RF) models to relate the flow-regime and intermittence classifications to several environmental characteristics of the gauging station catchments. The RF model of the flow-regime classification had a cross-validated Cohen's kappa of 0.47, indicating fair performance and the intermittence classification had poor performance (cross-validated Cohen's kappa of 0.35). Both classification models identified significant environment-intermittence associations, in particular with regional-scale climate patterns and also catchment area, shape and slope. However, we suggest that the fair-to-poor performance of the classification models is because intermittence is also controlled by processes operating at scales smaller than catchments, such as groundwater-table fluctuations and seepage through permeable channels. We suggest that high spatial heterogeneity in these small-scale processes partly explains the low spatial synchronization of zero flows. While 20% of gauges were classified as intermittent, the flow-regime model predicted 39% of all river segments to be intermittent, indicating that the gauging station network under-represents intermittent river segments in France. Predictions of regional patterns in flow intermittence provide useful information for applications including environmental flow setting, estimating assimilative capacity for contaminants, designing bio-monitoring programs and making preliminary predictions of the effects of climate change on flow intermittence.
Brief Communication: Likelihood of societal preparedness for global change: trend detection
Authors: Vogel R. M. , Rosner A. , Kirshen P. H.
Published: July 2013

Abstract. Anthropogenic influences on earth system processes are now pervasive, resulting in trends in river discharge, pollution levels, ocean levels, precipitation, temperature, wind, landslides, bird and plant populations and a myriad of other important natural hazards relating to earth system state variables. Thousands of trend detection studies have been published which report the statistical significance of observed trends. Unfortunately, such studies only concentrate on the null hypothesis of "no trend". Little or no attention is given to the power of such statistical trend tests, which would quantify the likelihood that we might ignore a trend if it really existed. The probability of missing the trend, if it exists, known as the type II error, informs us about the likelihood of whether or not society is prepared to accommodate and respond to such trends. We describe how the power or probability of detecting a trend if it exists, depends critically on our ability to develop improved multivariate deterministic and statistical methods for predicting future trends in earth system processes. Several other research and policy implications for improving our understanding of trend detection and our societal response to those trends are discussed.
Quantification of magma ascent rate through rockfall monitoring at the growing/collapsing lava dome of Volcán de Colima, Mexico
Authors: Mueller S. B. , Varley N. R. , Kueppers U. , Lesage P. , Reyes Davila G. Á. , Dingwell D. B.
Published: July 2013

Abstract. The most recent eruptive phase of Volcán de Colima, Mexico, started in 1998 and was characterized by dome growth with a variable effusion rate, interrupted intermittently by explosive eruptions. Between November 2009 and June 2011, activity at the dome was mostly limited to a lobe on the western side where it had previously started overflowing the crater rim, leading to the generation of rockfall events. As a consequence of this, no significant increase in dome volume was perceivable and the rate of magma ascent, a crucial parameter for volcano monitoring and hazard assessment could no longer be quantified via measurements of the dome's dimensions. Here, we present alternative approaches to quantify the magma ascent rate. We estimate the volume of individual rockfalls through the detailed analysis of sets of photographs (before and after individual rockfall events). The relationship between volume and infrared images of the freshly exposed dome surface and the seismic signals related to the rockfall events were then investigated. Larger rockfall events exhibited a correlation between its previously estimated volume and the surface temperature of the freshly exposed dome surface, as well as the mean temperature of rockfall mass distributed over the slope. We showed that for larger events, the volume of the rockfall correlates with the maximum temperature of the newly exposed lava dome as well as a proxy for seismic energy. It was therefore possible to calibrate the seismic signals using the volumes estimated from photographs and the count of rockfalls over a certain period was used to estimate the magma extrusion flux for the period investigated. Over the course of the measurement period, significant changes were observed in number of rockfalls, rockfall volume and hence averaged extrusion rate. The extrusion rate was not constant: it increased from 0.008 ± 0.003 to 0.02 ± 0.007 m3 s−1 during 2010 and dropped down to 0.008 ± 0.003 m3 s−1 again in March 2011. In June 2011, magma extrusion had come to a halt. The methodology presented represents a reliable tool to constrain the growth rate of domes that are repeatedly affected by partial collapses. There is a good correlation between thermal and seismic energies and rockfall volume. Thus it is possible to calibrate the seismic records associated with the rockfalls (a continuous monitoring tool) to improve volcano monitoring at volcanoes with active dome growth.
You followed my bot! Transforming robots into influential users in Twitter
Authors: Messias Johnnatan , Schmidt Lucas , Oliveira Ricardo , Benevenuto Fabrício
Published: July 2013

Systems that classify influential users in social networks have been used frequently and are referenced in scientific papers and in the media as an ideal standard of evaluation of influence in the Twitter social network. We consider such systems of evaluation to be complex and subjective, and we therefore suspect that they are vulnerable and easy to manipulate. Based on this, we performed experiments and analysis of two systems for ranking influence: Klout and Twitalyzer. We created simple robots capable of interacting by means of Twitter accounts, and we measured how influent they were. Our results show that it is possible to become influential through simple strategies. This suggests that the systems do not have ideal means to measure and classify influence.
Zooming into an Instagram City: Reading the local through social media
Authors: Hochman Nadav , Manovich Lev
Published: July 2013

How are users’ experiences of production, sharing, and interaction with the media they create mediated by the interfaces of particular social media platforms? How can we use computational analysis and visualizations of the content of visual social media (e.g., user photos, as opposed to upload dates, locations, tags and other metadata) to study social and cultural patterns? How can we visualize this media on multiple spatial and temporal scales? In this paper, we examine these questions through the analysis of the popular mobile photo–sharing application Instagram. First, we analyze the affordances provided by the Instagram interface and the ways this interface and the application’s tools structure users’ understanding and use of the “Instagram medium.” Next, we compare the visual signatures of 13 different global cities using 2.3 million Instagram photos from these cities. Finally, we use spatio–temporal visualizations of over 200,000 Instagram photos uploaded in Tel Aviv, Israel over three months to show how they can offer social, cultural and political insights about people’s activities in particular locations and time periods.
Reply to Roger E. Bissell:
Authors: Hardin Dennis C.
Published: July 2013

In his article, “The Logic of Liberty” (Journal of Ayn Rand Studies 12, no. 1), Roger Bissell uses an analytical diagram to show that Ayn Rand was wrong to characterize the differences between liberals and conservatives in terms of the mind-body dichotomy. Bissell claims that the key philosophical difference is not the mind-body dichotomy, but the malevolent universe premise. However, the diagram Bissell uses to discredit Rand's position exhibits a serious design flaw: it presumes the mind-body split by implying the metaphysical superiority of one over the other. This fundamental flaw in his analysis renders his criticism of Rand invalid.
Organizational Transformation to Promote Knowledge Transfer at Universities and R&D Institutions in Sonora, Mexico
Authors: Balderrama Jorge Inés León , López Lydia Venecia Gutiérrez , Lafarga Cuitláhuac Valdez
Published: July 2013

Using the results of an empirical study in the State of Sonora, Mexico, this paper reports on an attempt to identify trends and transformations that have taken place in the way knowledge transfer activities are organized and structured in higher education institutions and research centres. The research was designed to provide a characterization of organizational change that captures its complexity in different dimensions: corporate identity, new interface structures, new functions, new forms of human and financial resource management and intellectual property. To achieve this, information was collected and analysed from documentary sources and generated from a series of interviews with key personnel involved with science–industry linkages in the organizations studied.
Attracting and Retaining Student Talent from around the World
Authors: Vauterin Johanna Julia , Michelsen Karl-Erik , Linnanen Lassi
Published: July 2013

To be prepared for changing student talent pools in emerging geographical markets, and to remain attractive to the coming waves of student mobility, the European higher education sector must improve its ability to absorb international student talent in greater numbers. This paper presents an analysis of the nature and value of university–industry partnering as a means of attracting and retaining global student talent. The authors argue that global student talent recruitment lies at the heart of ‘knowledge transfer through people’. With this in mind, an inclusive picture of the university–industry partnering phenomenon is provided; and the role of collaborative experiencing and learning is examined. It was found that even university–industry collaborative practice dealing with global issues remains local in terms of engagement. The paper demonstrates that, by using interpretive and participatory methods, new insights can be gained into the university–industry practice of partnering to promote the attraction and retention of global student talent.
Attributional Style and Depression in Multiple Sclerosis
Authors: Vargas Gray A. , Arnett Peter A.
Published: July 2013

Several etiologic theories have been proposed to explain depression in the general population. Studying these models and modifying them for use in the multiple sclerosis (MS) population may allow us to better understand depression in MS. According to the reformulated learned helplessness (LH) theory, individuals who attribute negative events to internal, stable, and global causes are more vulnerable to depression. This study differentiated attributional style that was or was not related to MS in 52 patients with MS to test the LH theory in this population and to determine possible differences between illness-related and non-illness-related attributions. Patients were administered measures of attributional style, daily stressors, disability, and depressive symptoms. Participants were more likely to list non-MS-related than MS-related causes of negative events on the Attributional Style Questionnaire (ASQ), and more-disabled participants listed significantly more MS-related causes than did less-disabled individuals. Non-MS-related attributional style correlated with stress and depressive symptoms, but MS-related attributional style did not correlate with disability or depressive symptoms. Stress mediated the effect of non-MS-related attributional style on depressive symptoms. These results suggest that, although attributional style appears to be an important construct in MS, it does not seem to be related directly to depressive symptoms; rather, it is related to more perceived stress, which in turn is related to increased depressive symptoms.
Longitudinal Changes in Quality of Life and Related Psychosocial Variables in Australians with Multiple Sclerosis
Authors: Wollin Judy Ann , Spencer Nancy , McDonald Elizabeth , Fulcher Gary , Bourne Maureen , Simmons Rex D.
Published: July 2013

This study explored changes in quality of life (QOL) and psychosocial variables in a large cohort of people with multiple sclerosis (MS). A total of 1287 Australians with MS were administered self-report questionnaires at baseline and 24 months later to examine the impact of disease severity and duration, perceived stress, self-efficacy, depression, and social support on QOL and self-care. Over the 2-year survey period, MS remained stable for 70% of respondents. Disease severity correlated with social support at baseline but not at 24 months, when the only significant correlation with disease severity was that of the World Health Organization Quality of Life–100 instrument (WHOQOL-100) domain of Level of Independence. Although QOL improved across the WHOQOL-100 domains Physical, Psychological, Level of Independence, Social Relationships, and Environment, decreases were found in the WHOQOL-100 facet overall QOL and well-being as well as self-efficacy over the same time period. Hierarchical multiple regression was used to assess the utility of four control measures. MS disease severity and MS disease duration were entered at Step 1, explaining 16.1% of the variance in QOL. After entry of perceived stress, self-efficacy, social support, and the Depression, Anxiety and Stress Scale–21 (DASS-21) at Step 2, the total variance explained by the model as a whole was 55.8% (F6,1028 = 216.495, P < .001). Thus, even in the presence of stable disease and improvement in some WHOQOL-100 domains, overall QOL and self-efficacy had decreased at 2 years after the collection of baseline data. Loss of self-efficacy, increased stress, and depression are key factors in reduced QOL in people with MS.
High‐Efficiency Photoluminescence Wholly Aromatic Triarylamine‐based Polyimide Nanofiber with Aggregation‐Induced Emission Enhancement
Authors: Yen Hung‐Ju , Wu Jia‐Hao , Wang Wen‐Chang , Liou Guey‐Sheng
Published: July 2013

Novel AIE‐active, high Tg (up to 420 °C), and solution‐processable wholly aromatic polyimides with triarylamine chromophores are synthesized and fabricated into highly efficient photoluminescence (PL) nanofibers by an electrospinning method. The PL intensity of polymer solutions is induced by aggregation in poor solvents, and they could be fabricated into solid films with high PL quantum yields of up to 22%, demonstrating their aggregation‐induced emission feature. Moreover, the electrospun nanofibers have the highest PL quantum yield of 26% among aromatic polyimides, suggesting their great potential for high‐performance optoelectronic applications.
Implications of genetic testing in noncompaction/hypertrabeculation
Authors: Shieh Joseph T.C.
Published: July 2013

Noncompaction/hypertrabeculation is increasingly being recognized in children and adults, yet we understand little about the causes of disease. Genes associated with noncompaction/hypertrabeculation have been identified, but how can these assist in clinical management? Genomic technologies have also expanded tremendously, making testing more comprehensive, but they also present new questions given the tremendous diversity of phenotypes and variability of genomes. Here we present genetic evaluation strategies and assess clinical testing options for noncompaction/hypertrabeculation. We assess genes/gene panels offered by clinical laboratories and the potential for high‐throughput sequencing to fuel further discovery. We discuss challenges in cardiovascular genetics, such as interpretation of genomic variants, prediction and disease penetrance. © 2013 Wiley Periodicals, Inc.
Barth syndrome
Authors: Jefferies John L.
Published: July 2013

Barth syndrome (BTHS) is an X‐linked recessive disorder that is typically characterized by cardiomyopathy (CMP), skeletal myopathy, growth retardation, neutropenia, and increased urinary levels of 3‐methylglutaconic acid (3‐MGCA). There may be a wide variability of phenotypes amongst BTHS patients with some exhibiting some or all of these findings. BTHS was first described as a disease of the mitochondria resulting in neutropenia as well as skeletal and cardiac myopathies. Over the past few years, a greater understanding of BTHS has developed related to the underlying genetic mechanisms responsible for the disease. Mutations in the TAZ gene on chromosome Xq28, also known as G4.5, are responsible for the BTHS phenotype resulting in a loss‐of‐function in the protein product tafazzin. Clinical management of BTHS has also seen improvement. Patients with neutropenia are susceptible to life‐threatening bacterial infections with sepsis being a significant concern for possible morbidity and mortality. Increasingly, BTHS patients are suffering from heart failure secondary to their CMP. Left ventricular noncompaction (LVNC) and dilated CMP are the most common cardiac phenotypes reported and can lead to symptoms of heart failure as well as ventricular arrhythmias. Expanded treatment options for end‐stage myocardial dysfunction now offer an opportunity to change the natural history for these patients. Herein, we will provide a current review of the genetic and molecular basis of BTHS, the clinical features and management of BTHS, and potential future directions for therapeutic strategies. © 2013 The Authors. American Journal of Medical Genetics Part C: Seminars in Medical Genetics published by Wiley Periodicals, Inc.
Energetic Monoanionic Salts of 3,5‐Dinitropyridin‐2‐ol
Authors: Ghule Vikas D. , Srinivas Dharavath , Muralidharan Krishnamurthi
Published: July 2013

3,5‐Dinitropyridin‐2‐ol (DNP) and thirteen of its monoanionic salts (1–13) containing diverse cations, including nitrogen‐rich molecules, were readily synthesized and fully characterized by 1H, 13C NMR, and IR spectroscopy, as well as thermogravimetric differential thermal analyses, mass spectroscopy, and elemental analyses. Favorable structure–property relationships were achieved by changing the cationic moieties. The densities of the DNP salts range between 1.60–1.74 g cm−3, whereas detonation velocities and pressures were calculated to be in the range 6.51–7.56 km s−1 and 17.57–24.84 GPa, respectively. Based on contributions to the energetic properties, the most promising cation for use in energetic DNP salts of those studied were nitroguanidine and 3‐nitro‐1,2,4‐triazole.
Medical therapy reduces microbiota diversity and evenness in surgically recalcitrant chronic rhinosinusitis
Authors: Liu Cindy M. , Soldanova Katerina , Nordstrom Lora , Dwan Michael G. , Moss Owain L. , Contente‐Cuomo Tania L. , Keim Paul , Price Lance B. , Lane Andrew P.
Published: July 2013

Background

Chronic rhinosinusitis (CRS) is a highly prevalent and heterogeneous condition frequently treated with antibiotics and corticosteroid therapy. However, the effect of medical therapy on sinus microbiota remains unknown.

Methods

We enrolled CRS patients (n = 6) with patent maxillary antrostomies and active mucosal inflammation, who had not received antibiotics or corticosteroids in the previous 8 weeks. A pretreatment and posttreatment maxillary sinus swab was collected, from which DNA was extracted, pyrosequenced, and analyzed using a naïve Bayesian classifier and ecological analyses.

Results

Four patients showed significant improvement in endoscopic appearance. The shifts in microbiota in response to therapy were highly individualized. There was no single common microbiota profile among patients with similar clinical outcomes, but overall there was significant decrease in microbiota diversity (t(5) = 2.05, p = 0.10) and evenness (t(5) = 2.28, p = 0.07) after treatment.

Conclusion

Our findings strongly correlate with earlier studies that examined the impact of antibiotics on human microbiota. We observed that posttreatment, patients frequently became colonized by taxa that are less susceptible to the prescribed antibiotics. Our findings highlight the challenge in seeking generalizable diagnostic and therapeutic options in CRS, particularly regarding microbiological response and outcomes.
Systematic review and meta‐analysis of total intravenous anesthesia and endoscopic sinus surgery
Authors: DeConde Adam S. , Thompson Christopher F. , Wu Edward C. , Suh Jeffrey D.
Published: July 2013

Background

Total intravenous anesthesia (TIVA) has been shown in some studies to impact visual field, blood loss, and cardiovascular parameters during endoscopic sinus surgery when compared to inhalational anesthesia (IA). These variables are critical in endoscopic sinus surgery. A systematic review and meta‐analysis was undertaken to discern the impact of TIVA vs IA in endoscopic sinus surgery.

Methods

MEDLINE (1950 to October 20, 2012) was searched using a search strategy designed to include all randomized controlled trials (RCTs) that discussed TIVA, IA, and endoscopic sinus surgery. An abstract search was then used to identify RCTs directly comparing TIVA and IA in endoscopic sinus surgery. All articles selected then underwent full‐text review. Data on visual field scores, blood loss, and cardiovascular parameters was then extracted, compared, and analyzed.

Results

There were 42 articles identified by the search strategy. Full‐text review identified 9 articles that met eligibility criteria and contained extractable data. Although inconsistently reported, preoperative characteristics (Lund‐Mackay scores and history of nasal polyps) were similar (p > 0.05) between the 2 groups. No difference was found between heart rate, mean arterial pressure, anesthesia time, operative time, or estimated blood loss. Only 7 studies reported a visibility score, but overall favored the TIVA group (p < 0.001).

Conclusion

Current evidence supporting TIVA is limited to a handful of inconsistently controlled and reported studies. Standardized grading of visibility scores and preoperative characteristics would better establish the role of TIVA in endoscopic sinus surgery.
Von einzelnen H‐Brücken zu ausgedehnten H‐verbrückten Drähten: niederdimensionale Modellsysteme für die Schwingungsspektroskopie vernetzter Flüssigkeiten
Authors: Olschewski Martin , Knop Stephan , Lindner Jörg , Vöhringer Peter
Published: July 2013

Die anomalen Eigenschaften von Wasser erschließen sich uns nur dann vollends, wenn wir Wasserstoffbrücken untersuchen. Diese Behauptung beruht auf der statistischen Mechanik, die uns lehrt, wie Struktur und thermodynamische Eigenschaften von Fluiden und dichten Flüssigkeiten aus den intermolekularen Kräften zu berechnen sind. Im Falle komplexer, vernetzter Flüssigkeiten bilden solche Rechnungen allerdings ein beachtliches – oder gar unüberwindbares – Hindernis, das unser noch immer begrenztes Verständnis von Wasserstoffbrücken offenbart. Es bedarf weiterer experimenteller Forschung an wasserstoffverbrückten Systemen, um eine umfassende Theorie vernetzter Flüssigkeiten zu entwickeln. Dieser Aufsatz gibt einen Einblick in eine neue experimentelle Methode, die verwendet wird, um ultraschnelle Strukturdynamiken von Wasserstoffbrücken zu erforschen: die zweidimensionale Infrarotspektroskopie. Wir diskutieren ihre Anwendung auf wasserstoffverbrückte Systeme mit steigender Komplexität: von der einzelnen Wasserstoffbrücke eines Diols bis hin zu niederdimensionalen, ausgedehnten Netzwerken stereoselektiv synthetisierter Polyalkohole.
Bipolare Elektrochemie
Authors: Fosdick Stephen E. , Knust Kyle N. , Scida Karen , Crooks Richard M.
Published: July 2013

Eine bipolare Elektrode (BPE) ist ein elektrisch leitfähiges Objekt, an dessen äußeren Enden elektrochemische Reaktionen ablaufen, ohne dass ein direkter Ohm’scher Kontakt vorhanden sein muss. Es reicht, an eine Elektrolytlösung mit eingetauchter BPE eine Spannung anzulegen, und ab einer bestimmten Potentialdifferenz zwischen BPE und Lösung laufen Oxidations‐ und Reduktionsreaktionen ab. Meist reicht eine einzige Gleichstromquelle oder sogar nur eine Batterie aus, um selbst sehr große Elektrodenanordnungen mit Spannung zu versorgen. Somit können neue Materialen für vielfältige Anwendungen kabellos elektrolytisch hergestellt und auf ihre Eigenschaften hin überprüft werden. Auch bipolar‐elektrochemische Anwendungen mit mobilen, sich frei in Lösung bewegenden Elektroden, die Mikroschwimmer genannt werden, sind möglich.
From Single Hydrogen Bonds to Extended Hydrogen‐Bond Wires: Low‐Dimensional Model Systems for Vibrational Spectroscopy of Associated Liquids
Authors: Olschewski Martin , Knop Stephan , Lindner Jörg , Vöhringer Peter
Published: July 2013

It is fair to say that if we ever wish to understand the anomalous properties of water, we need to study hydrogen bonds. Such a statement is based on statistical mechanics, which tells us how to calculate the structure and the thermodynamic properties of fluids and dense liquids from the forces between the particles. However, in the case of complex associated liquids, such calculations present a formidable—if not even insurmountable—challenge, which largely reflects our still‐limited understanding of the hydrogen‐bonding phenomenon itself. More experimental research on hydrogen‐bonded systems is required to develop a comprehensive, satisfactory theory for associated liquids. This Review gives an introduction to the latest experimental technique currently being used to study the ultrafast structural dynamics of hydrogen bonds, namely two‐dimensional infrared spectroscopy, and its applications to hydrogen‐bonded systems of systematically increasing complexity, starting from the single hydrogen bond of a diol to low‐dimensional extended networks of stereoselectively synthesized polyalcohols.
Lewis Base Catalysis of the Mukaiyama Directed Aldol Reaction: 40 Years of Inspiration and Advances
Authors: Beutner Gregory L. , Denmark Scott E.
Published: July 2013

Since the landmark publications of the first directed aldol addition reaction in 1973, the site, diastereo‐, and enantioselective aldol reaction has been elevated to the rarefied status of being both a named and a strategy‐level reaction (the Mukaiyama directed aldol reaction). The importance of this reaction in the stereoselective synthesis of untold numbers of organic compounds, both natural and unnatural, cannot be overstated. However, its impact on the field extends beyond the impressive applications in synthesis. The directed aldol reaction has served as a fertile proving ground for new concepts and new methods for stereocontrol and catalysis. This Minireview provides a case history of how the challenges of merging site selectivity, diastereoselectivity, enantioselectivity, and catalysis into a unified reaction manifold stimulated the development of Lewis base catalyzed aldol addition reactions. The evolution of this process is chronicled from the authors’ laboratories as well as in those of Professor Teruaki Mukaiyama.
Cost-effectiveness analysis of enhancements to angioplasty for infrainguinal arterial disease
Authors: Kearns B C , Michaels J A , Stevenson M D , Thomas S M
Published: July 2013

Background

The aim was to perform an economic evaluation of the cost-effectiveness of endovascular enhancements to percutaneous transluminal balloon angioplasty (PTA) with bail-out bare metal stents for infrainguinal peripheral arterial disease.

Methods

The following interventions were considered: PTA with no bail-out stenting, PTA with bail-out drug-eluting stents, drug-coated balloons, primary bare metal stents, primary drug-eluting stents, endovascular brachytherapy, stent-grafts and cryoplasty. A discrete-event simulation model was developed to assess the relative cost-effectiveness of the interventions from a health service perspective over a lifetime. Populations of patients with intermittent claudication (IC) and critical leg ischaemia (CLI) were modelled separately. Univariable and probabilistic sensitivity analyses were undertaken. Effectiveness was measured by quality-adjusted life-years (QALYs).

Results

For both patient populations, the use of drug-coated balloons dominated all other options by having both lower lifetime costs and greater effectiveness. For willingness-to-pay thresholds between £0 and £100 000 per additional QALY, the probability of drug-coated balloons being cost-effective was at least 58·3 per cent for patients with IC and at least 72·2 per cent for patients with CLI. Sensitivity analyses showed that the results were robust to different assumptions regarding the clinical benefits attributable to the interventions.

Conclusion

The use of drug-coated balloons represents a cost-effective alternative to the use of PTA with bail-out bare metal stents.
Systematic review and meta-analysis of additional technologies to enhance angioplasty for infrainguinal peripheral arterial occlusive disease
Authors: Simpson E L , Michaels J A , Thomas S M , Cantrell A J
Published: July 2013

Background

There are several additional techniques designed to enhance conventional percutaneous transluminal balloon angioplasty (PTA). This systematic review assessed current evidence on the clinical effectiveness of additional techniques for infrainguinal peripheral arterial occlusive disease (PAD).

Methods

Relevant electronic databases, including MEDLINE, were searched in May 2011. The population comprised participants with symptomatic PAD undergoing endovascular treatment for disease distal to the inguinal ligament. Interventions were additional techniques compared with conventional PTA. Main outcome measures were restenosis and need for reintervention. Randomized clinical trials (RCTs) of clinical effectiveness were assessed for quality and data were extracted. Where appropriate, meta-analysis was undertaken to produce risk ratios (RRs).

Results

Forty RCTs were selected. Meta-analysis showed a significant benefit in reducing restenosis rates at 6 months for self-expanding stents (RR 0·49) and drug-coated balloons (RR 0·40), and at 12 months for endovascular brachytherapy (RR 0·63). There was also evidence that use of a stent-graft significantly reduced restenosis compared with PTA, as did drug-eluting stents compared with bare-metal stents. Meta-analysis showed that use of drug-coated balloons was associated with significantly lower reintervention rates than PTA alone at 6 months (RR 0·24) and 24 months (RR 0·27) of follow-up. There was also evidence of significantly lower reintervention rates for self-expanding stents at 6 months. Other techniques did not show significant treatment effects for restenosis or reintervention.

Conclusion

The conclusions of this review should be tempered by small sample sizes, lack of clinical outcome measures and differing outcome definitions, making direct comparison across trials difficult. However, self-expanding stents, drug-eluting stents and drug-coated balloons appeared to be the most promising technologies worthy of future study.
Treatment of intermittent claudication
Authors: Earnshaw J J , Lavis R
Published: July 2013

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