bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic analysis of biomass and photosynthetic parameters in wheat grown in different light intensities
Authors: Li Hongwei , Wang Gui , Zheng Qi , Li Bin , Jing Ruilian , Li Zhensheng
Published: January 2014

Growth light intensities largely determine photosynthesis, biomass, and grain yield of cereal crops. To explore the genetic basis of light responses of biomass and photosynthetic parameters in wheat (Triticum aestivum L.), a quantitative trait locus (QTL) analysis was carried out in a doubled haploid (DH) population grown in low light (LL), medium light (ML), and high light (HL), respectively. The results showed that the wheat seedlings grown in HL produced more biomass with lower total chlorophyll content (Chl), carotenoid content, and maximum photochemical efficiency of photosystem II (Fv/Fm) while the wheat seedlings grown in LL produced less biomass with higher Chl compared with those grown in ML. In total, 48 QTLs were identified to be associated with the investigated parameters in relation to growth light intensities. These QTLs were mapped to 15 chromosomes which individually explained 6.3%–36.0% of the phenotypic variance, of which chromosomes 3A, 1D, and 6B were specifically involved in LL response, 5D and 7A specifically involved in ML response, and 4B specifically involved in HL response. Several light‐responsive QTLs were co‐located with QTLs for photosynthetic parameters, biomass, and grain weight under various conditions which may provide new hints to uncover the genetic control of photosynthesis, biomass, and grain weight.
More Innovation with Less? A Strategic Contingency View of Slack Resources, Information Search, and Radical Innovation
Authors: Troilo Gabriele , De Luca Luigi M. , Atuahene‐Gima Kwaku
Published: January 2014

This study investigates the nonobvious interrelationship between slack resources and radical innovation. While organizational slack and innovation literature has implicitly recognized a link between these constructs, at least two important aspects of their relationship have been overlooked. First, little attention has been paid to the mechanisms by which slack resources become beneficial for radical innovation. Drawing on information search and organizational learning theories, we propose distal search activity—searching for information outside the current knowledge domain of the firm—as a mediating variable between slack resources and radical innovation. Second, little consideration has been given to the strategic orientation of the firm as the context in which slack resources are deployed to enhance radical innovation. Adopting Miles and Snow's typology of strategic archetypes, we propose a moderating role of strategy in the slack resources–distal search–radical innovation chain of relations. We tested our hypotheses on a sample of Chinese high‐technology firms, using multiple informant survey data and regression analysis. Our results indicate that slack resources are positively related to radical innovation, and that this relationship is partially mediated by distal search. Thus, there appear to be two routes (one direct, one indirect) to transform slack resources into radical innovation. Further, moderation analysis shows that the effect of slack resources on distal search is strongest among analyzers, while the effect of distal search on radical innovation is strongest among defenders. In sum, our results suggest that analyzers are relatively more dependent on the amount of slack resources compared to other strategy types, that is, resource constraints would have a more negative effect on analyzers. We discuss theoretical and managerial implications of our study and conclude by suggesting future research opportunities.
Perceptions of Material Resources in Innovation Projects: What Shapes Them and How Do They Matter?
Authors: Weiss Matthias , Hoegl Martin , Gibbert Michael
Published: January 2014

Studies on the role of material resources for team performance in innovation projects have provided inconclusive results. This paper focuses on team members' perceptions of the provided material resources' adequacy to address this gap. Understanding what drives perceptions of material resource adequacy may not only reconcile conflicting results in the literature, but may also provide much‐needed guidance for project funding, so as to maximize innovation project performance. Further, the analyses in this paper differentiate between two outcome dimensions of innovation project performance, namely, the degree of new product quality and new product novelty, and thus offer a more fine‐grained analysis of the relationship between perceptions of material resource adequacy and innovation project teams' performance. The posited hypotheses are tested using a sample consisting of survey data from 121 innovation projects in the electronics industry. To avoid common source bias, data from different respondent groups, that is, team leaders, team members, and team external managers of the examined innovation projects, were used. The results of the regression analyses identify team potency and workload as socio‐cognitive drivers of innovation project teams' perceptions of material resource adequacy. Moreover, it is found that perceived material resource adequacy relates positively to new product quality, while it relates negatively to new product novelty. This paper thus provides an important step toward disentangling the ambiguity surrounding the relationship between material resource adequacy and innovation project teams' performance, showing that a key finding of cognitive psychology seems to hold also on the team level of inquiry: the significant influence of socio‐cognitive factors on perceptions. This finding paves the way for putting more attention in research on innovation and project management on cognitive aspects, in particular considering mechanisms behind the formation of team perceptions. Further, the results provide evidence for differential effects of perceived material resource adequacy on innovation project performance, depending on the indicators used for measuring the outcomes of an innovation project. This contributes necessary detail to studying the relationship between material resource adequacy and innovation project performance, which so far has produced inconclusive results, suggesting that these contradictions might result to a large degree from different operationalizations of innovation project performance. On a practical level, the findings of this paper suggest that material resource adequacy seems not to be a catch‐all variable, influencing innovation project outcomes in a uniform way. It appears to be a useful lever for influencing team outcomes depending on the desired result, which may be manipulated by shaping team variables that exert a systematic influence on perceptions of material resource adequacy.
The Effect of Selective Openness on Value Creation in User Innovation Communities
Authors: Balka Kerstin , Raasch Christina , Herstatt Cornelius
Published: January 2014

Open innovation research and practice recognize the important role of external complementors in value creation. At the same time, firms need to retain exclusive control over some essential components to capture value from their product and/or service system. This paper contributes to the literature by analyzing some of the trade‐offs between openness to external value creation and closedness for internal value capture. It focuses on selective openness as a key variable and investigates how it affects value creation by external complementors, specifically the members of user innovation communities. Openness, it is hypothesized, matters to community members: The more open a product design is, the higher their sense of involvement in the innovation project, and the larger the effort they devote to it. Unlike prior literature, different forms and loci of openness are distinguished, specifically the transparency, accessibility, and replicability of different components of the product being developed.

Hypotheses are tested based on survey data (n = 309) from 20 online communities in the consumer electronics and information technology hardware industries. Multilevel regression analysis is used to account for clustering, and thus nonindependent data, at the community level. We find that openness indeed increases community members’ involvement in the innovation project and their contributions to it. Interestingly, however, some forms and loci of openness strongly affect community perceptions and behavior, while others have limited or no impact. This finding suggests that, at least in relation to user communities, the trade‐off that firms face between external value creation and internal value capture is softer than hitherto understood. Contingency factors that may be able to explain these patterns are advanced. For example, users are expected to value the form of openness that they have the capabilities and incentives to exploit.

The findings in this paper extend the literature on selective openness in innovation. They emphasize the need to study the demand for different forms of openness at the subsystem level and align supply‐side strategies to it. In managerial practice, a careful assessment of the demand for openness enables firms to successfully use selective openness and to effectively appropriate value from selectively open systems.
The Mediating Role of Strategic Orientations on the Relationship between Ambidexterity‐Oriented Decisions and Innovative Ambidexterity
Authors: Kortmann Sebastian
Published: January 2014

Building on upper echelon theory and strategic process theory, this article analyzes the relationship between ambidexterity‐oriented decisions and innovative ambidexterity. While ambidexterity‐oriented decisions embrace the capability of top management teams to manage contradictory strategic directions, namely adaptability and alignment, innovative ambidexterity captures the ability of firms to simultaneously develop discontinuous and incremental innovations. In addition to the direct relationship between ambidexterity‐oriented decisions and innovative ambidexterity, it is argued that innovation orientation and cost orientation denote two cultural implementation mechanisms that mediate this effect. Using two top‐executive data sets collected in the United States (n = 83) and India (n = 78), the empirical analysis shows that innovation orientation and cost orientation partially mediate the direct influence of ambidexterity‐oriented decisions on innovative ambidexterity, thus further explaining how formulated decisions made by the top management team nurture ambidextrous innovation behavior. Hence, this article extends prior literature that emphasizes a positive influence of top managers on innovation through incorporating an organizational ambidexterity perspective. Second, this study contributes to ambidexterity literature through integrating strategic process theory. While ambidexterity‐oriented decisions primarily relate to strategy formulation, innovation orientation and cost orientation are associated with strategy implementation. The results show that both strategic subprocesses are vital in enabling ambidextrous innovation behavior. Third, an operationalization for the ability of top management to balance adaptability‐ and alignment‐oriented decisions is provided based on prior literature.
Novel Approaches to Examine Passage, Student, and Question Effects on Reading Comprehension
Authors: Miller Amanda C. , Davis Nicole , Gilbert Jennifer K. , Cho Sun‐Joo , Toste Jessica R. , Street James , Cutting Laurie E.
Published: January 2014

Reading comprehension is influenced by sources of variance associated with the reader and the task. To gain insight into the complex interplay of multiple sources of influence, we employed crossed random‐effects item response models. These models allowed us to simultaneously examine the degree to which variables related to the type of passage and student characteristics influenced students’ (n = 94; mean age = 11.97 years) performance on two indicators of reading comprehension: different types of comprehension questions and passage fluency. We found that variables related to word recognition, language, and executive function were influential across various types of passages and comprehension questions and also predicted a reader's passage fluency. Further, an exploratory analysis of two‐way interaction effects was conducted. Results suggest that understanding the relative influence of passage, question, and student variables has implications for identifying struggling readers and designing interventions to address their individual needs.
Distribution patterns of the invasive herbivore Siganus luridus (Rüppell, 1829) and its relation to native benthic communities in the central Aegean Sea, Northeastern Mediterranean
Authors: Giakoumi Sylvaine
Published: January 2014

The present study explores the distribution of the invasive herbivore fish Siganus luridus (Rüppell 1829) and its relationship to native herbivores and macroalgal assemblages in the shallow sublittoral of the Cyclades Archipelago, Aegean Sea, Greece. In situ underwater surveys of herbivore abundance (fishes and sea urchins) and algal coverage were carried out at 180 sampling sites in 18 islands. Siganus luridus accounted for 17% of the total herbivore abundance, with a decrease in relative abundance from the southeastern to the northwestern islands. In Santorini Island (in the southeast of the study area) S. luridus abundance accounted for 90% of the total herbivore fish abundance, while in Kea Island (at the northwestern limit of the study area), S. luridus was absent. The spatial variation of minimum sea surface temperature is possibly the reason for its distributional pattern. Siganus luridus abundance was found to be positively correlated to the native herbivore Sparisoma cretense (Linnaeus 1758). A significant negative relationship was found between the abundance of the invasive species and the sum of erect and canopy algae cover (Dictyotales and Cystoseira spp.), which are the main components of its diet in the region. On the other hand, its occurrence was particularly high in barren sites. The results arising from this study reinforce evidence from studies in the Eastern Mediterranean Basin that the expansion of the invasive species S. luridus may have profound impacts on native communities in the Mediterranean infralittoral zone.
Seed germination and rising atmospheric CO2 concentration: a meta‐analysis of parental and direct effects
Authors: Marty Charles , BassiriRad Hormoz
Published: January 2014

Plant regeneration from seed is largely governed by germinability and speed of germination. These fitness components have received considerably less attention in CO2 research relative to studies of vegetative or reproductive output responses. Moreover, the limited literature has not been rigorously examined for generalizable patterns of responses and/or potential mechanisms. We used a meta‐analytic approach to summarize literature results of seed germination characteristics in response to parental CO2 enrichment (eCO2). The direct effects of eCO2 on germination components were also analyzed. The data set came from 29 original research papers encompassing 64 species and 116 observations. Across all studies, parental eCO2 increased subsequent germination by 9%, but the responses varied among species by as much as 300%. The response was significantly higher in trees than in other life forms. With the exception of crops, parental eCO2 also increased germination rate in most life forms and functional groups. Despite a considerable interspecific variability, we found a positive correlation between germination success and seed mass responses to parental eCO2. Therefore, the observed diversity of regeneration success responses to parental eCO2 is partly controlled by the direction and magnitude of changes in seed mass.
Transient Neonatal Zinc Deficiency Due to a New Autosomal Dominant Mutation in Gene SLC30A2 (ZnT‐2)
Authors: Lova Navarro Miguel , Vera Casaño Ángel , Benito López Carmen , Fernández Ballesteros María D. , Godoy Díaz Daniel J. , Crespo Erchiga Antonio , Romero Brufau Santiago
Published: January 2014

Transient neonatal zinc deficiency (TNZD) has a clinical presentation similar to that of acrodermatitis enteropathica but is caused by a low zinc concentration in maternal breast milk. TNZD becomes clinically evident during breastfeeding and is resolved by weaning and the introduction of complementary nutrition. We present a 4‐month‐old girl with TNZD due to a new autosomal dominant mutation (663delC) in the maternal SLC30A2 gene not previously described in the literature.
An Atrophic, Telangiectatic Patch at the Distal Border of the Tongue: A Mucous Membrane Manifestation of Xeroderma Pigmentosum
Authors: Bologna Sheyla Batista , Harumi Nakajima Teshima Tathyane , Lourenço Silvia Vanessa , Nico Marcello Menta Simonsen
Published: January 2014

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by clinical and cellular sensitivity, pigmentary changes, and early development of malignancies in sun‐exposed mucocutaneous and ocular structures due to a defective ability to repair intracellular DNA damage. Individuals with XP also have a greater frequency of oral cancer, particularly squamous cell carcinoma of the anterior third of the tongue. The current study reports four cases of XP that exhibited a characteristic crescent‐shaped, atrophic, telangiectatic area on the distal border of the tongue and correlates this lesion with the development of tumors at this site during follow‐up. The tongue lesion was photographed and biopsied in the four patients. During routine follow‐up visits, new biopsies were performed if additional tongue lesions were observed. The studied lesions were similar in the four patients. During follow‐up, squamous cell carcinoma developed in one patient and pyogenic granuloma developed in three patients and was relapsing in one. The lesion remained stable in one patient during the study. The atrophic and telangiectatic patches probably occur because of chronic sun damage to the exposed portion of the tongue, and this area has a high predisposition for the development of benign and malignant tumors.
Initial Cutaneous Manifestations of Hutchinson‐Gilford Progeria Syndrome
Authors: Rork Jillian F. , Huang Jennifer T. , Gordon Leslie B. , Kleinman Monica , Kieran Mark W. , Liang Marilyn G.
Published: January 2014

Hutchinson–Gilford progeria syndrome (HGPS) is a rare, uniformly fatal, premature aging disease with distinct dermatologic features. We sought to identify and describe the initial skin and hair findings as potential diagnostic signs of the disease. We performed a chart review of the structured initial intake histories of 39 individuals with HGPS enrolled in clinical trials from 2007 to 2010 at Boston Children's Hospital, limited to cutaneous history from birth to 24 months. Medical photographs were provided through the clinical trials and the Progeria Research Foundation Medical and Research Database at Brown University Center for Gerontology and Healthcare Research. All 39 patients reported skin and hair abnormalities within the first 24 months of life. Pathologies included sclerodermoid change, prominent superficial veins, dyspigmentation, and alopecia. The mean age of presentation for each finding was <12 months. The most frequently reported skin feature was sclerodermoid change, which commonly involved the abdomen and bilateral lower extremities. Prominent superficial vasculature manifested as circumoral cyanosis and pronounced veins on the scalp and body. Hypo‐ and hyperpigmentation were observed over areas of sclerodermoid change. Scalp alopecia progressed in a distinct pattern, with preservation of the hair over the midscalp and vertex areas for the longest period of time. HGPS has distinct cutaneous manifestations during the first 2 years of life that may be the first signs of disease. Awareness of these findings could expedite diagnosis.
EMPIRICAL ANALYSIS OF AGGLOMERATION ECONOMIES IN THE JAPANESE ASSEMBLY‐TYPE MANUFACTURING INDUSTRY FOR 1985–2000: USING AGGLOMERATION AND COAGGLOMERATION INDICES
Authors: Tokunaga Suminori , Kageyama Masahiro , Akune Yuko , Nakamura Ryohei
Published: January 2014

This empirical study finds that positive but weak agglomeration economies resulted from the agglomeration of Japan's assembly‐type manufacturing industry during 1985–2000. Estimation results particularly indicate positive externalities from coagglomeration and very slightly increasing returns to scale. Traditional studies conceive of agglomeration economies as being related to localization and urbanization. We, however, estimate a flexible translog production function using four‐digit Standard Industrial Classification industry panel data and Ellison and Glaeser's agglomeration index with the same industry and coagglomeration index with different industry groups. We theoretically obtain appropriate and significant results without the homotheticity restriction.
Cord blood graft composition impacts the clinical outcome of allogeneic stem cell transplantation
Authors: Wikell H. , Ponandai‐Srinivasan S. , Mattsson J. , Gertow J. , Uhlin M.
Published: January 2014

Introduction

Despite routine use of umbilical cord blood (CB) grafts as stem cell source for allogeneic stem cell transplantations, much remains unknown regarding their cell composition and correlation with clinical outcome.

Methods

We analyzed material from 30 CB units used for allogeneic hematopoietic stem cell transplantation by multicolor flow cytometry. Phenotypic data were correlated with various clinical outcomes such as survival, graft‐versus‐host disease (GVHD), relapse, rejection, viral reactivation, and bacteremia.

Results

We found that above‐median frequencies of CD69+ T cells, naïve CD8+ T cells, and CD127+ B cells in the CB graft were each associated with significantly improved patient survival. Moreover, a statistically significant correlation was seen between higher levels of CD94+ T cells and herpes simplex virus and varicella zoster virus reactivation post transplantation. A similar correlation was seen for the frequency of CD95+ cells in total CD3+, as well as CD4+ and CD8+ T‐cell subsets, and viral reactivation. Finally, a higher frequency of naïve CD8+ T cells was associated with the incidence of acute GVHD.

Conclusion

Our study highlights the importance of further exploration of graft composition before CB transplantation as a tool for risk prediction.
The roots of plant defenses: integrative multivariate analyses uncover dynamic behaviors of gene and metabolic networks of roots elicited by leaf herbivory
Authors: Gulati Jyotasana , Baldwin Ian T. , Gaquerel Emmanuel
Published: January 2014

High‐throughput analyses have frequently been used to characterize herbivory‐induced reconfigurations in plant primary and secondary metabolism in above‐ and below‐ground tissues, but the conclusions drawn from these analyses are often limited by the univariate methods used to analyze the data. Here we use our previously described multivariate time‐series data analysis to evaluate leaf herbivory‐elicited transcriptional and metabolic dynamics in the roots of Nicotiana attenuata. We observed large, but transient, systemic responses in the roots that contrasted with the pattern of co‐linearity observed in the up‐ and downregulation of genes and metabolites across the entire time series in treated and systemic leaves. Using this newly developed approach for the analysis of whole‐plant molecular responses in a time‐course multivariate data set, we simultaneously analyzed stress responses in leaves and roots in response to the elicitation of a leaf. We found that transient systemic responses in roots resolved into two principal trends characterized by: (i) an inversion of root‐specific semi‐diurnal (12 h) transcript oscillations and (ii) transcriptional changes with major amplitude effects that translated into a distinct suite of root‐specific secondary metabolites (e.g. alkaloids synthesized in the roots of N. attenuata). These findings underscore the importance of understanding tissue‐specific stress responses in the correct day–night phase context and provide a holistic framework for the important role played by roots in above‐ground stress responses.
Estimating the transfusion transmission risk of Q fever
Authors: Oei Welling , Kretzschmar Mirjam E.E. , Zaaijer Hans L. , Coutinho Roel , van der Poel Cees L. , Janssen Mart P.
Published: January 2014

Background

The Q fever outbreaks in the Netherlands in 2007 to 2009 initiated discussion on the necessity of measures to prevent transmission through blood products. Risk assessments help transfusion regulators decide when and where measures are required. This study assesses the transfusion transmission (TT) risk of Q fever using the European Up‐Front Risk Assessment Tool (EUFRAT) model.

Study Design and Methods

We estimated the number of Q fever infections in recipients during the 2007 to 2009 outbreaks' peaks using selected notification data; estimates are calculated from the probability of a donor being infected. We compared this probability to the prevalence of infection estimated from an independent donation testing study and using the Biggerstaff model. We also quantified the risk reduction by implementing measures such as donation testing and donor deferral.

Results

At the peak of the 2007, 2008, and 2009 outbreaks, there were an estimated 0.21, 0.96, and 1.59 recipients infected with Q fever, respectively. Between June 1, 2009, and January 31, 2010, the probability of a donor being infected with Q fever in the high‐incidence areas was estimated at 260 (95% confidence interval, 192‐340) per 100,000 donors, consistent with results from the donation testing study. The EUFRAT estimates were also consistent with estimates from the Biggerstaff model. Scenario analyses showed that donation testing provided the largest risk reduction of various risk reduction strategies.

Conclusion

The TT risk of Q fever during the 2007 to 2009 outbreaks was small, a result that is consistent with results of other studies. EUFRAT can be applied successfully to support decision making during outbreaks.
Productivity and Learning‐by‐exporting: A Firm‐level Analysis of Indian Manufacturing
Authors: Pattnayak Sanja S. , Thangavelu Shandre M.
Published: January 2014

In this paper, we examine whether firms become productive by learning through exporting. To this end, we estimate the production function using microdata of Indian manufacturing firms operating in the period 1991–2001. In contrast to studies on developed countries, our results provide evidence that Indian manufacturing firms are experiencing a rise in productivity through entering export markets and thus experience the learning effect. We also find that there is a productivity rise prior to exporting. Therefore, our results also support the self‐selection mechanism for exporting.
Agreement between allergen‐specific IgE assays and ensuing immunotherapy recommendations from four commercial laboratories in theUSA
Authors: Plant Jon D. , Neradelik Moni B. , Polissar Nayak L. , Fadok Valerie A. , Scott Brian A.
Published: January 2014

Background

Canine allergen‐specificIgEassays in theUSAare not subjected to an independent laboratory reliability monitoring programme.

Hypothesis/Objectives

The aim of this study was to evaluate the agreement of diagnostic results and treatment recommendations of four serum IgE assays commercially available in theUSA.

Methods

Replicate serum samples from 10 atopic dogs were submitted to each of four laboratories for allergen‐specific IgE assays (ACTT®,VARLLiquid Gold,ALLERCEPT®and Greer®Aller‐g‐complete®). The interlaboratory agreement of standard, regional panels and ensuing treatment recommendations were analysed with the kappa statistic (κ) to account for agreement that might occur merely by chance. Six comparisons of pairs of laboratories and overall agreement among laboratories were analysed for ungrouped allergens (as tested) and also with allergens grouped according to reported cross‐reactivity and taxonomy.

Results

The overall chance‐corrected agreement of the positive/negative test results for ungrouped and grouped allergens was slight (κ = 0.14 and 0.13, respectively). Subset analysis of the laboratory pair with the highest level of diagnostic agreement (κ = 0.36) found slight agreement (κ = 0.13) for ungrouped plants and fungi, but substantial agreement (κ = 0.71) for ungrouped mites. The overall agreement of the treatment recommendations was slight (κ = 0.11). Altogether, 85.1% of ungrouped allergen treatment recommendations were unique to one laboratory or another.

Conclusions and clinical importance

Our study indicated that the choice of IgE assay may have a major influence on the positive/negative results and ensuing treatment recommendations.
Prior‐based artifact correction (PBAC) in computed tomography
Authors: Heußer Thorsten , Brehm Marcus , Ritschl Ludwig , Sawall Stefan , Kachelrieß Marc
Published: January 2014

Purpose:

Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion.

Methods:

The proposed prior‐based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image.

Results:

The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry‐based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact‐free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient‐specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result.

Conclusions:

The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.
Dosimetric characterization and output verification for conical brachytherapy surface applicators. Part II. High dose rate 192Ir sources
Authors: Fulkerson Regina K. , Micka John A. , DeWerd Larry A.
Published: January 2014

Purpose:

Historically, treatment of malignant surface lesions has been achieved with linear accelerator based electron beams or superficial x‐ray beams. Recent developments in the field of brachytherapy now allow for the treatment of surface lesions with specialized conical applicators placed directly on the lesion. Applicators are available for use with high dose rate (HDR)192Ir sources, as well as electronic brachytherapy sources. Part I of this paper discussed the applicators used with electronic brachytherapy sources. Part II will discuss those used with HDR 192Ir sources. Although the use of these applicators has gained in popularity, the dosimetric characteristics have not been independently verified. Additionally, there is no recognized method of output verification for quality assurance procedures with applicators like these.

Methods:

This work aims to create a cohesive method of output verification that can be used to determine the dose at the treatment surface as part of a quality assurance/commissioning process for surface applicators used with HDR electronic brachytherapy sources (Part I) and192Ir sources (Part II). Air‐kerma rate measurements for the 192Ir sources were completed with several models of small‐volume ionization chambers to obtain an air‐kerma rate at the treatment surface for each applicator. Correction factors were calculated using MCNP5 and EGSnrc Monte Carlo codes in order to determine an applicator‐specific absorbed dose to water at the treatment surface from the measured air‐kerma rate. Additionally, relative dose measurements of the surface dose distributions and characteristic depth dose curves were completed in‐phantom.

Results:

Theoretical dose distributions and depth dose curves were generated for each applicator and agreed well with the measured values. A method of output verification was created that allows users to determine the applicator‐specific dose to water at the treatment surface based on a measured air‐kerma rate.

Conclusions:

The novel output verification methods described in this work will reduce uncertainties in dose delivery for treatments with these kinds of surface applicators, ultimately improving patient care.
The first clinical implementation of electromagnetic transponder‐guided MLC tracking
Authors: Keall Paul J. , Colvill Emma , O’Brien Ricky , Ng Jin Aun , Poulsen Per Rugaard , Eade Thomas , Kneebone Andrew , Booth Jeremy T.
Published: January 2014

Purpose:

We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder‐guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre.

Methods:

An electromagnetic transponder‐based positioning system (Calypso) was modified to send the target position output to in‐house‐developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real‐time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder‐guided MLC tracking was for a prostate cancer patient being treated with dual‐arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder‐guided MLC tracking we recorded the in‐room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used.

Results:

The total in‐room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V60. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V60 from that planned, even for the small motion.

Conclusions:

The real‐time beam‐target correction method, electromagnetic transponder‐guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy.
Mammographic compression after breast conserving therapy: Controlling pressure instead of force
Authors: de Groot J. E. , Broeders M. J. M. , Branderhorst W. , den Heeten G. J. , Grimbergen C. A.
Published: January 2014

Purpose:

X‐ray mammography is the primary tool for early detection of breast cancer and for follow‐up after breast conserving therapy (BCT). BCT‐treated breasts are smaller, less elastic, and more sensitive to pain. Instead of the current force‐controlled approach of applying the same force to each breast, pressure‐controlled protocols aim to improve standardization in terms of physiology by taking breast contact area and inelasticity into account. The purpose of this study is to estimate the potential for pressure protocols to reduce discomfort and pain, particularly the number of severe pain complaints for BCT‐treated breasts.

Methods:

A prospective observational study including 58 women having one BCT‐treated breast and one untreated nonsymptomatic breast, following our hospitalˈs 18 decanewton (daN) compression protocol was performed. Breast thickness, applied force, contact area, mean pressure, breast volume, and inelasticity (mean E‐modulus) were statistically compared between the within‐women breast pairs, and data were used as predictors for severe pain, i.e., scores 7 and higher on an 11‐point Numerical Rating Scale. Curve‐fitting models were used to estimate how pressure‐controlled protocols affect breast thickness, compression force, and pain experience.

Results:

BCT‐treated breasts had on average 27% smaller contact areas, 30% lower elasticity, and 30% higher pain scores than untreated breasts (allp < 0.001). Contact area was the strongest predictor for severe pain (p < 0.01). Since BCT‐treatment is associated with an average 0.36 dm2 decrease in contact area, as well as increased pain sensitivity, BCT‐breasts had on average 5.3 times higher odds for severe pain than untreated breasts. Model estimations for a pressure‐controlled protocol with a 10 kPa target pressure, which is below normal arterial pressure, suggest an average 26% (range 10%–36%) reduction in pain score, and an average 77% (range 46%–95%) reduction of the odds for severe pain. The estimated increase in thickness is +6.4% for BCT breasts.

Conclusions:

After BCT, women have hardly any choice in avoiding an annual follow‐up mammogram. Model estimations show that a 10 kPa pressure‐controlled protocol has the potential to reduce pain and severe pain particularly for these women. The results highly motivate conducting further research in larger subject groups.
Effects of Examiner Strength on Reliability of Hip-Strength Testing Using a Handheld Dynamometer
Authors: Krause David A. , Neuger Mathew D. , Lambert Kimberly A. , Johnson Amanda E. , DeVinny Heather A. , Hollman John H.
Published: January 2014

Context:

Hip-muscle impairments are associated with a variety of lower-extremity dysfunctions. Accurate assessment in the clinical setting can be challenging due to the strength of hip muscles relative to examiner strength.

Objective:

To examine the influence of examiner strength and technique on manual hip-strength testing using a handheld dynamometer.

Design:

Repeated measures.

Setting:

Research laboratory.

Participants:

30 active adults (age 24 ± 1.4 y).

Interventions:

Three examiners of different strength performed manual muscle tests (MMT) in 2 different positions for hip extension, abduction, and external rotation using a MicroFet handheld dynamometer. Examiner strength was quantified via a 1-repetition-maximum leg press and chest press with a Keiser A420 pneumatic resistance machine.

Main Outcome Measures:

Intrarater reliability (ICC3,1), interrater reliability (ICC2,1), and measured torque values.

Results:

Intrarater reliability for all measurements ranged from .82 to .97. Interrater reliability ranged from .81 to .98. Main effects for hip extension revealed a significant difference in torque values between examiners and between techniques. For the short-lever hip-abduction and seated hip-external-rotation tests, there was a significant difference between examiners. There was no significant difference in measured torque values between examiners with the long-lever hip-abduction or the prone hip-external-rotation tests.

Conclusions:

MMT of the hip may be performed with high reliability by examiners of different strength. To obtain valid MMT measurements of hip muscles, examiners must consider their own strength and testing techniques employed. The authors recommend a long-lever technique for hip abduction and a prone position for testing hip external rotation to minimize the influence of examiner strength. Both positions appear to provide mechanical advantages to the examiner compared with the alternative techniques. The authors are unable to recommend a preferred hip-extension-testing technique to minimize the influence of examiner strength.
Kinematic Analysis of Selected Reach Directions of the Star Excursion Balance Test Compared With the Y-Balance Test
Authors: Fullam Karl , Caulfield Brian , Coughlan Garrett F. , Delahunt Eamonn
Published: January 2014

Context:

The Star Excursion Balance Test (SEBT) and the Y-Balance Test (YBT) have 3 common reach directions: anterior (ANT), posteromedial (PM), and posterolateral (PL). Previous research has indicated that reach-distance performance on the ANT reach direction of the SEBT differs from that on the YBT. Kinematic patterns associated with the ANT reach direction of the SEBT and YBT need to be investigated to fully understand this difference, along with the PM and PL reach directions, to deduce any kinematic discrepancies between the 2 balance tests.

Objective:

To compare and contrast the kinematic patterns associated with test performance on the reach directions common to the SEBT and YBT.

Design:

Controlled laboratory study.

Setting:

University laboratory.

Participants:

15 healthy male (age 23.33 ± 2.02 y, height 1.77 ± 0.04 m, body mass 80.00 ± 9.03 kg) and 14 healthy female (age 21.14 ± 1.66 y, height 1.63 ± 0.06 m, body mass 59.58 ± 7.61 kg) volunteers.

Intervention:

Each participant performed 3 trials of the ANT, PM, and PL reach directions of the SEBT and YBT on their dominant leg.

Main Outcome Measures:

Sagittal-plane lower-limb kinematic profiles were recorded using a 3-D motion-analysis system. Reach distances were also recorded for each reach direction.

Results:

A significant main effect (P < .05) was observed for test condition with participants reaching farther on the ANT reach direction of the SEBT compared with the YBT. While reaching in the ANT direction participants were characterized by a more flexed position of the hip joint at the point of maximum reach on the YBT (27.94° ± 13.84°) compared with the SEBT (20.37° ± 18.64°).

Conclusions:

Based on these observed results, the authors conclude that test performance on the SEBT and YBT differ in terms of dynamic neuromuscular demands, as evidenced by differences in reach distances achieved in the ANT reach direction and associated test kinematic profile.
Effect of Gender on the Quadriceps-to-Hamstrings Coactivation Ratio During Different Exercises
Authors: Harput Gulcan , Soylu A. Ruhi , Ertan Hayri , Ergun Nevin , Mattacola Carl G.
Published: January 2014

Context:

Coactivation ratio of quadriceps to hamstring muscles (Q:H) and medial to lateral knee muscles (M:L) contributes to the dynamic stability of the knee joint during movement patterns recommended during rehabilitation and important for daily function.

Objective:

To compare the quadriceps-to-hamstring and medial-to-lateral knee muscles' coactivation ratios between men and women during the following closed kinetic chain exercises performed on a balance board: forward lunge, side lunge, single-leg stance, and single-leg squat.

Design:

Cross-sectional.

Participants:

20 healthy subjects (10 female and 10 male).

Main Outcome Measures:

Surface electromyography was used to measure the activation level of quadriceps (vastus lateralis and medialis) and hamstrings (biceps femoris and medial hamstrings) during forward- and side-lunge, single-leg-stance, and single-leg-squat exercises. Subjects were instructed during each exercise to move into the test position and to hold that position for 15 s. EMG was recorded during the 15-s isometric period where subjects tried to maintain a “set” position while the foot was on a balance board. Analysis of variance was used for statistical analysis.

Results:

There was a significant exercise-by-gender interaction for Q:H ratio (F3,48 = 6.63, P = .001), but the exercise-by-gender interaction for M:L ratio was not significant (F3,48 = 1.67, P = .18). Women showed larger Q:H ratio in side-lunge exercises than men (P = .002). Both genders showed larger M:L and lower Q:H ratio in a single-leg-stance exercise than in the other exercises.

Conclusions:

The results indicate that the forward- and side-lunge and single-leg-squat exercises should not be recommended as exercise where a balanced coactivation between quadriceps and hamstring muscles is warranted. Single-leg-stance exercise could be used when seeking an exercise where the ratio is balanced for both women and men.
Concurrent and Discriminant Validity of the Star Excursion Balance Test for Military Personnel With Lateral Ankle Sprain
Authors: Bastien Maude , Moffet Hélène , Bouyer Laurent , Perron Marc , Hébert Luc J. , Leblond Jean
Published: January 2014

The Star Excursion Balance Test (SEBT) has frequently been used to measure motor control and residual functional deficits at different stages of recovery from lateral ankle sprain (LAS) in various populations. However, the validity of the measure used to characterize performance—the maximal reach distance (MRD) measured by visual estimation—is still unknown.

Objectives:

To evaluate the concurrent validity of the MRD in the SEBT estimated visually vs the MRD measured with a 3D motion-capture system and evaluate and compare the discriminant validity of 2 MRD-normalization methods (by height or by lower-limb length) in participants with or without LAS (n = 10 per group).

Results:

There is a high concurrent validity and a good degree of accuracy between the visual estimation measurement and the MRD gold-standard measurement for both groups and under all conditions. The Cohen d ratios between groups and MANOVA products were higher when computed from MRD data normalized by height.

Conclusion:

The results support the concurrent validity of visual estimation of the MRD and the use of the SEBT to evaluate motor control. Moreover, normalization of MRD data by height appears to increase the discriminant validity of this test.
Grid-Layout and Theta-Modulation of Layer 2 Pyramidal Neurons in Medial Entorhinal Cortex
Authors: Ray Saikat , Naumann Robert , Burgalossi Andrea , Tang Qiusong , Schmidt Helene , Brecht Michael
Published: January 2014

Entorhinal Cell Clusters

There is considerable interest in understanding the function of neurons in layer 2 of the medial entorhinal cortex and how they generate their unique firing patterns, which are important in the recall of facts and past events (see the Perspective by

Blair

).

Ray
et al.

(p.
891
, published online 23 January) investigated principal cells in layer 2 by immunoreactivity, projection patterns, microcircuit analysis, and assessment of temporal discharge properties in awake, freely moving animals. In tangential sections, pyramidal neurons were clustered into patches arranged in a hexagonal grid—very similar to the patterns observed in grid cell spatial firing. These patches received selective cholinergic innervation, which is critical for sustaining grid cell activity.

Kitamura
et al.

(p.
896
, published online 23 January) found that these cells drive a hippocampal circuit by projecting directly to the hippocampal CA1 area and synapsing with a distinct class of inhibitory neurons. This circuit provides feed-forward inhibition in combination with excitatory inputs from layer 3 cells of the medial entorhinal cortex, projecting to CA1 pyramidal cells to determine the strength and time window of temporal associative inputs.
The New Madrid Seismic Zone: Not Dead Yet
Authors: Page Morgan T. , Hough Susan E.
Published: January 2014

Statistical modeling of aftershock occurrences shows that the central United States is still active, despite low active deformation rates.