bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of digital competence in 7th grade: a multilevel analysis
Authors: Hatlevik O.E. , Ottestad G. , Throndsen I.
Published: April 2014

Since 2006, the ability to use information and communication technology (ICT) has been included as a key competence in the curriculum inNorway, and specific competence aims are developed for most grades. The aim of this study was to identify students' ability to useICTaccording to the competence aims, and to examine factors that can predict students' digital competence. A sample of 1793 students and 125 school leaders from 125 schools was used. The findings show variation in digital competence both between students and between schools. Results from a multilevel analysis showed that higher levels of mastery orientation and self‐efficacy (i.e., motivation) and the students' family background (i.e., language integration and the number of books at home) were predictors of students' levels of digital competence. Additionally, when school leaders reported higher levels of culture for professional development among the teachers at school, increased levels of digital competence were found among students. Challenges for schools and teachers to support students' motivation and to emphasize digital inclusion still prevail.
Feeding efficiency of planktivores under disturbance, the effect of water colour, predation threat and shoal composition
Authors: Nurminen L. , Estlander S. , Olin M. , Lehtonen H.
Published: April 2014

The consumption of phantom midge Chaoborus flavicans larvae by Perca fluviatilis showed clear response to water colour, predation threat and shoal composition with the most significant negative effect for water colour. In the case of Rutilus rutilus, no similar combined response was observed and the total prey consumption was significantly negatively affected by predation threat of Esox lucius. The results suggest that differences in life‐history traits may result in disparity in species‐specific responses to disturbance.
Long‐Term Impact of Early Life Events on Physiology and Behaviour
Authors: Boersma G. J. , Bale T. L. , Casanello P. , Lara H. E. , Lucion A. B. , Suchecki D. , Tamashiro K. L.
Published: April 2014

This review discusses the effects of stress and nutrition throughout development and summarises studies investigating how exposure to stress or alterations in nutrition during the pre‐conception, prenatal and early postnatal periods can affect the long‐term health of an individual. In general, the data presented here suggest that that anything signalling potential adverse conditions later in life, such as high levels of stress or low levels of food availability, will lead to alterations in the offspring, possibly of an epigenetic nature, preparing the offspring for these conditions later in life. However, when similar environmental conditions are not met in adulthood, these alterations may have maladaptive consequences, resulting in obesity and heightened stress sensitivity. The data also suggest that the mechanism underlying these adult phenotypes might be dependent on the type and the timing of exposure.
Challenges to human uniqueness: bipedalism, birth and brains
Authors: Roberts A. M. , Thorpe S. K. S.
Published: April 2014

Historically, paleoanthropology has focused on explaining human uniqueness. This review paper highlights several recent challenges to key features that have been considered to be exclusive to hominins, testing three long‐standing theories in evolutionary anthropology. The knuckle‐walking quadrupedalism model describes the evolution of modern gorillines, panins and hominins from a common, knuckle‐walking ancestor. But the homology of knuckle‐walking in African apes has been questioned. Although habitual bipedalism is unique to humans, it may have developed from occasional bipedalism in ancestors, without a quadrupedal stage. The obstetric dilemma seeks to explain the helplessness of human infants. The timing of human birth is seen as uniquely constrained by fetal head size and maternal pelvic width. An alternative hypothesis suggests that birth occurs when fetal demand for energy threatens to exceed maternal supply; this mechanism also appears to operate in other mammals. The expensive tissue hypothesis suggests that the expansion of energy‐hungry brain tissue in hominins was offset by a reduction in gut tissue. But although large brains are correlated with both good quality diets and relatively short guts in primates, the causes of this correlation are not clear. An alternative suggestion is that the large human brain is paid for by savings in other functions, such as locomotion and reproduction, and that a concurrent expansion of low‐cost adipose tissue in humans keeps metabolic rate low. In the past, paleoanthropology may have focused on defining a boundary between humans and animals, but recent research has seen a shift of focus to exploring humans as animals. Aspects of bipedalism, birth and brains have been considered to be exclusively human, but in the last few years even these have been eroded. It is the package of features that characterizes Homo sapiens that is unique.
An overview of the utility of population simulation software in molecular ecology
Authors: Hoban Sean
Published: April 2014

Stochastic simulation software that simultaneously model genetic, population and environmental processes can inform many topics in molecular ecology. These include forecasting species and community response to environmental change, inferring dispersal ecology, revealing cryptic mating, quantifying past population dynamics, assessing in situ management options and monitoring neutral and adaptive biodiversity change. Advances in population demographic–genetic simulation software, especially with respect to individual life history, landscapes and genetic processes, are transforming and expanding the ways that molecular data can be used. The aim of this review is to explain the roles that such software can play in molecular ecology studies (whether as a principal component or a supporting function) so that researchers can decide whether, when and precisely how simulations can be incorporated into their work. First, I use seven case studies to demonstrate how simulations are employed, their specific advantage/necessity and what alternative or complementary (nonsimulation) approaches are available. I also explain how simulations can be integrated with existing spatial, environmental, historical and genetic data sets. I next describe simulation features that may be of interest to molecular ecologists, such as spatial and behavioural considerations and species' interactions, to provide guidance on how particular simulation capabilities can serve particular needs. Lastly, I discuss the prospect of simulation software in emerging challenges (climate change, biodiversity monitoring, population exploitation) and opportunities (genomics, ancient DNA), in order to emphasize that the scope of simulation‐based work is expanding. I also suggest practical considerations, priorities and elements of best practice. This should accelerate the uptake of simulation approaches and firmly embed them as a versatile tool in the molecular ecologist's toolbox.
Can frequent precipitation moderate the impact of drought on peatmoss carbon uptake in northern peatlands?
Authors: Nijp Jelmer J. , Limpens Juul , Metselaar Klaas , van der Zee Sjoerd E. A. T. M. , Berendse Frank , Robroek Bjorn J. M.
Published: April 2014

Northern peatlands represent a large global carbon store that can potentially be destabilized by summer water table drawdown. Precipitation can moderate the negative impacts of water table drawdown by rewetting peatmoss (Sphagnum spp.), the ecosystem's key species. Yet, the frequency of such rewetting required for it to be effective remains unknown. We experimentally assessed the importance of precipitation frequency for Sphagnum water supply and carbon uptake during a stepwise decrease in water tables in a growth chamber.

CO2 exchange and the water balance were measured for intact cores of three peatmoss species (Sphagnum majus, Sphagnum balticum and Sphagnum fuscum) representative of three hydrologically distinct peatland microhabitats (hollow, lawn and hummock) and expected to differ in their water table–precipitation relationships.

Precipitation contributed significantly to peatmoss water supply when the water table was deep, demonstrating the importance of precipitation during drought. The ability to exploit transient resources was species‐specific; S. fuscum carbon uptake increased linearly with precipitation frequency for deep water tables, whereas carbon uptake by S. balticum and S. majus was depressed at intermediate precipitation frequencies.

Our results highlight an important role for precipitation in carbon uptake by peatmosses. Yet, the potential to moderate the impact of drought is species‐specific and dependent on the temporal distribution of precipitation.
The insula: a critical neural substrate for craving and drug seeking under conflict and risk
Authors: Naqvi Nasir H. , Gaznick Natassia , Tranel Daniel , Bechara Antoine
Published: April 2014

Drug addiction is characterized by the inability to control drug use when it results in negative consequences or conflicts with more adaptive goals. Our previous work showed that damage to the insula disrupted addiction to cigarette smoking—the first time that the insula was shown to be a critical neural substrate for addiction. Here, we review those findings, as well as more recent studies that corroborate and extend them, demonstrating the role of the insula in (1) incentive motivational processes that drive addictive behavior, (2) control processes that moderate or inhibit addictive behavior, and (3) interoceptive processes that represent bodily states associated with drug use. We then describe a theoretical framework that attempts to integrate these seemingly disparate findings. In this framework, the insula functions in the recall of interoceptive drug effects during craving and drug seeking under specific conditions where drug taking is perceived as risky and/or where there is conflict between drug taking and more adaptive goals. We describe this framework in an evolutionary context and discuss its implications for understanding the mechanisms of behavior change in addiction treatments.
A tradeoff between perceived predation risk and energy conservation revealed by an immune challenge experiment
Authors: Nord Andreas , Sköld‐Chiriac Sandra , Hasselquist Dennis , Nilsson Jan‐Åke
Published: April 2014

Energy is typically a limiting factor for animals during boreal winters, when low temperatures increase the cost of thermoregulation at the same times as short day‐lengths and snow cover constrain foraging opportunities. Under these circumstances animals use a suite of behavioural and physiological adaptations to avoid overnight starvation. However, it is poorly understood how such strategies are affected by increased energy demands from other physiological systems. Thus, we used free‐ranging blue tits, Cyanistes caeruleus, to test if competing demands for energy (here induced by a non‐inflammatory, antibody‐mediated immune challenge) would affect nocturnal body temperature (a predictor of energy expenditure in small animals) and energy‐saving nest box roosting behaviour. We also assessed if the immune challenge incurred long‐term survival costs. We found no evidence that body temperature regulation differed between immune‐challenged and saline‐injected birds. Nor did the immune challenge reduce survival to the next breeding season. However, old (second winter or older) immune‐challenged birds continued roosting in nest boxes to a larger extent at the peak immune response, despite increased perceived predation risk induced by the preceding capture and immunization. In contrast, old control birds were less prone to roost in nest boxes after capture and saline injection. This difference was less pronounced in young (first winter) birds. We interpret the increased risk‐taking behaviour in immune‐challenged birds as a consequence of a higher need for exploiting the thermal benefits of nest box roosting to reduce energy loss. This suggests that resource deficiency might be a stronger predictor of overnight survival than the threat of nocturnal predation in this system. As such, our study provides insights into the classic tradeoff between starvation and predation risk, in suggesting that priority is given to minimizing the risk of starvation in situations where both starvation and predation risks increase during cold winter nights.
A consistent occupancy–climate relationship across birds and mammals of the Americas
Authors: Boucher‐Lalonde Véronique , Morin Antoine , Currie David J.
Published: April 2014

At broad spatial scales, species richness is strongly related to climate. Yet, few ecological studies attempt to identify regularities in the individual species distributions that make up this pattern. Models used to describe species distributions typically model very complex responses to climate. Here, we test whether the variability in the distributions of birds and mammals of the Americas relates to mean annual temperature and precipitation in a simple, consistent way. Specifically, we test if simple mathematical models can predict, as a first approximation, the geographical variation in individual species’ probability of occupancy for 3277 non‐migratory bird and 1659 mammal species. We find a Gaussian model, where the probability of occupancy of a 104 km2 quadrat decreases symmetrically and gradually around a species ‘optimal’ temperature and precipitation, was generally the best model, explaining an average of 35% of the deviance in probability of occupancy. The inclusion of additional terms had very small and idiosyncratic effects across species. The Gaussian occupancy–climate relationship appears general among species and taxa and explains nearly as much deviance as complex models including many more parameters. Therefore, we propose that hypotheses aiming to explain the broad‐scale distribution of species or species richness must also predict generally Gaussian occupancy–climate relationships.

Synthesis

Science aims to identify regularities in a complex natural world. General patterns should be identified before one searches for potential mechanisms and contingencies. However, species geographic distributions are often modelled as complex (sometimes black box), species‐specific, functions of their environment. We asked whether a simple model could account for as much of the geographic variation in a species' probability of occupancy, and be widely applicable across thousands of species. As a first approximation, we found that a simple Gaussian occupancy‐climate relationship is very common in Nature, whether it be causal or not.
Ectopic wisdom tooth at the mandibular ascending ramus
Authors: Kansy K. , Gander E. , Staff C. , Hoffmann J. , Freier K.
Published: April 2014

Twenty to thirty per cent of wisdom teeth are partially or completely retained. A displacement of such teeth into the ascending ramus of the mandible is far less frequent with few reported cases in the literature. The case of a young lady and a review of the literature are presented. A 27‐year‐old woman was referred to the specialist department by her dentist. At the age of 22, a panoramic radiograph had been taken for an agenesis of the patient's lower left second molar. At this time, the lower left third molar was situated slightly submucosally at the angle of the mandible. In the present radiograph, the tooth had migrated into the ascending ramus of the mandible. Clinically, there was no pain, sensation disorder, disturbed occlusion, limited mouth opening or any other complaint. Due to significant tooth migration within the last 6 years, operative removal of the displaced tooth was recommended. Computed tomography showed that the distal root was in direct relation with the inferior alveolar nerve. Treatment was performed via a transoral approach. Post‐operative follow‐up was uneventful. This case stresses the importance of long‐time follow‐up of retained teeth and their immense potential for migration.
Unusually large and aggressive traumatic bone cysts of the jaws – a series of five cases
Authors: Bhattacharyya I. , Islam M.N. , Chehal H.K. , Reith J.D. , Islam S. , Fernandes R. , McNally S.J. , Cohen D.M.
Published: April 2014

Traumatic bone cysts (TBC) in the jaws are asymptomatic, slow growing, usually non‐expansile lesions commonly diagnosed during routine radiographic examination. Unusually large and relatively aggressive TBC of the jaws are uncommon. The aetiology and pathogenesis of this entity remain unclear. In the extremities, however, lesions similar to the TBC of jaws are noted but are much larger and exhibit significant growth potential. This series of cases highlights unusually large and aggressive nature of TBC of jaws that is generally considered to be innocuous and non‐expansile with minimal clinical significance. TBC may be considered in the differential diagnosis of large mandibular radiolucent lesions.
Jasmine Does Not Bloom in Pyongyang: The Persistent Non‐transition in North Korea
Authors: Fiori Antonio , Kim Sunhyuk
Published: April 2014

At the beginning of 2011, the world was shaken by an “earthquake” which struck the Middle East and African regions. Following the Arab Spring or Jasmine Revolution, many pundits stated that North Korea could be the next to be affected by this wind of change, and the North Korean dictatorial leadership could collapse soon. This assumption acquired further validity soon after Kim Jong‐il's death. This paper draws on the democratic transition and consolidation literature that has grown considerably in the last decades. According to this literature, a few factors facilitate and promote democratization – most prominently, an elite split between hardliners and softliners; the emergence of civil society and its pro‐democracy movement; and a certain degree of international pressure. Through an analysis of these factors, this paper shows why North Korea is “resistant to change” and will not follow in the Middle East's footsteps. We argue that the main reason for the non‐transition in North Korea is the absence of the conditions that have been identified in the democratization literature as critical factors promoting democratic transition.
SouthKorea and the Pitfalls ofEastAsian Monetary Regionalism: Do Neighbors Mean Neighborly Behavior?
Authors: Cho Youngwon
Published: April 2014

In the aftermath of theAsian financial crisis, monetary regionalism has been widely advocated as a means to shelterEastAsia from not only the volatility of global financial markets but also from theUS‐dominated International Monetary Fund. While the primary obstacle to deepening regional monetary cooperation centered around theChiangMaiInitiative (CMI) is cogently identified as being political, the existing literature focuses mostly on the rivalry between the likely lenders,China andJapan, and neglects the likely borrowers. Using the case ofSouthKorea, this paper provides a cautionary tale of theCMIfrom a borrower's perspective. Any workable liquidity‐support arrangement, regional or otherwise, requires a robust surveillance mechanism to address the problem of moral hazard inherent to such a lending facility. In turn, an effective surveillance mechanism inevitably implies a significant political leverage for the lenders and vulnerability for the borrowers, an outcome that cannot be assumed to be avoidable by theCMIjust by the virtue of its regional scope. There is little basis to expect that being neighbors necessarily means neighborly behavior; mere geographic proximity does not makeChina andJapan any less self‐interested than theUnitedStates, nor does it makeKorea's potential political costs more tolerable.
Spinal Cord Stimulation of the Dorsal Root Ganglion for Groin Pain—A Retrospective Review
Authors: Schu Stefan , Gulve Ashish , ElDabe Sam , Baranidharan Ganesan , Wolf Katharina , Demmel Walter , Rasche Dirk , Sharma Manohar , Klase Daniel , Jahnichen Gunnar , Wahlstedt Anders , Nijhuis Harold , Liem Liong
Published: April 2014

Background

Spinal cord stimulation (SCS) is a standard treatment option for chronic neuropathic pain. However, some anatomical pain distributions are known to be difficult to cover with traditional SCS‐induced paresthesias and/or may also induce additional, unwanted stimulation. We present the results from a retrospective review of data from patients with groin pain of various etiologies treated using neuromodulation of the dorsal root ganglion (DRG).

Methods

Data from 29 patients with neuropathic groin pain were reviewed. Patients underwent trial therapy where specifically designed leads were implanted at the target DRGs between T12 and L4. Patients who had a successful trial (> 50% improvement) received the fully implantable neuromodulation system. Pain scores were captured on a visual analog scale (VAS) at baseline and at regular follow‐up visits.

Results

Twenty‐five patients (86.2%) received fully implantable neurostimulators, and the average follow‐up period was 27.8 ± 4.3 (standard error of the mean, SEM) weeks. The average pain reduction was 71.4 ± 5.6%, and 82.6% (19/23) of patients experienced a > 50% reduction in their pain at the latest follow‐up. Individual cases showed improvement with a variety of etiologies and pain distributions; a subanalysis of postherniorrhaphy cohort also showed significant improvement.

Conclusions

Early findings suggest that neuromodulation of the DRG may be an effective treatment for chronic neuropathic pain conditions in the groin region. This technique offers a useful alternative for pain conditions that do not always respond optimally to traditional SCS therapy. Neuromodulation of the DRG provided excellent cross‐dermatomal paresthesia coverage, even in cases with patients with discrete pain areas. The therapy can be specific, sustained, and independent of body position.
Genetic association of within‐boll yield components and boll morphological traits with fibre properties in upland cotton (Gossypium hirsutum L.)
Authors: Tang Feiyu , Xiao Wenjun
Published: April 2014

Knowledge of genetic relationships between within‐boll yield components and fibre quality is essential for simultaneous improvement of lint yield and fibre quality in upland cotton (Gossypium hirsutum L.). Nine parents and their F1 progeny with reciprocals from a 3 × 6 factorial mating design were grown in 2008 and 2009. Seven within‐boll yield components and two boll morphological traits and the three fibre quality parameters were analysed based on a conditional additive/dominance (AD) genetic model. Results showed that boll length contributed to the largest proportion of phenotypic, additive and dominance variances for UHM length; seed index contributed to the largest proportion of phenotypic and additive variances for fibre strength; boll width made the largest contribution to phenotypic and additive variances and the second largest contribution to dominance‐by‐environment interaction variance for micronaire, indicating that they played an important role than the other traits for fibre length, strength and fineness/maturity, respectively. It is worthy of note that those correlations between boll shape and fibre quality apply only to the nine parents and the resultant hybrids in this study and do not imply a cause and effect relationship.
Rapidly Involuting Congenital Hemangioma with Pustules: Two Cases
Authors: Hughes Rosalind , McAleer Maeve , Watson Rosemarie , Collins Sinead , Irvine Alan , White Martin
Published: April 2014

Rapidly involuting congenital hemangiomas (RICHs) are rare tumors that usually present as well‐defined bluish or violaceous plaques or tumors with scattered telangiectasias and central or peripheral pallor. We report two previously unreported cases of RICH with associated pustules.
Perceived Racism and Suicide Ideation: Mediating Role of Depression but Moderating Role of Religiosity among African American Adults
Authors: Walker Rheeda L. , Salami Temilola K. , Carter Sierra E. , Flowers Kelci
Published: April 2014

Suicide is a public health problem for African Americans who are young and of working age. The purpose of this study was to examine mediated and moderated effects of perceived racism on suicide ideation in a community sample of 236 African American men and women. Measures of suicide ideation, depression symptoms, intrinsic/extrinsic religiosity, and perceived racism were administered. Perceived racial discrimination was directly and indirectly associated with suicide ideation. For participants who reported low levels of extrinsic religiosity, the mediated effect of perceived racism (via depression symptoms) was significant. These findings provide some insight into suicide vulnerability for specific subgroups of African Americans.
Investigating Elementary Mathematics Curricula: Focus on Students With Learning Disabilities
Authors: Hord Casey , Newton Jill A.
Published: April 2014

The purpose of this study was to investigate three elementary mathematics curricula to examine the accessibility for students with learning disabilities (LD) with regards to challenges associated with working memory. We chose to focus on students' experiences when finding the area of composite shapes due to the multiple steps involved for solving these problems and the potential for these problems to tax working memory. We conducted a qualitative analysis of how each curriculum provided opportunities for students with LD to engage with these problems. During our analysis, we focused on instruction that emphasized visual representations (e.g., manipulatives, drawings, and diagrams), facilitated mathematical conversations, and developed cognitive and metacognitive skills. Our findings indicated a need for practitioners to consider how each curriculum provides instruction for storage and organization of information as well as how each curriculum develops students' thinking processes and conceptual understanding of mathematics. We concluded that all three curricula provide potentially effective strategies for teaching students with LD to solve multi‐step problems, such as area of composite shapes problems, but teachers using any of these curricula will likely need to supplement the curriculum to meet the needs of students with LD.
Enhancing Teaching Assistants' (TAs') Inquiry Teaching by Means of Teaching Observations and Reflective Discourse
Authors: Miller Kristen , Brickman Peggy , Oliver J. Steve
Published: April 2014

Recent education reform efforts advocate teaching the process of science (inquiry) in undergraduate lecture and laboratory classes. To meet this challenge, professional development for the graduate student instructors (teaching assistants, or TAs) often assigned to teach these classes is needed. This study explored the implementation of an observation protocol designed to support peer observation and reflection among TAs teaching inquiry‐based undergraduate biology laboratories. The researchers of this study and TA‐peers who are experienced in teaching inquiry used the protocol to observe novice TAs at the beginning, mid‐point, and end of a semester‐long teaching assignment. Novice TAs used a modified version of this protocol to observe an experienced and a novice TA. Analysis of post‐semester interview data indicated engaging in both sets of observations and post‐observation discussions facilitated by the protocol gave novice TAs new ways to teach content, guidance on implementing pedagogical theory, and means to improve communications with students and classroom management skills. Researchers also used quantitative data collected from the observations to document frequency of teaching and student behaviors associated with teaching inquiry and how these frequencies changed during the semester. Considerations for how to use both sets of data to inform changes in TA professional development are discussed.
Randomising Development: Geography, Economics and the Search for Scientific Rigour
Authors: Webber Sophie
Published: April 2014

Development economics has become something of an innovator within the discipline of economics, due to its adoption of experimental and statistical analysis techniques. In this paper I give examples of this new trend in development economics: randomised‐control trials, natural experiments, specialist analytical techniques like pre‐analysis plans, and evidence‐driven policy evaluation. I explore this novel experimental development economics in conversation with current argumentation in economic/development geography about economics. I do this in order to ask whether this experimental trend responds to any of these geographical critiques. Although I find that this new development economics repeats many of the tendencies of economics that geographers find so specious, it does pose challenges to economic/development geography, which I explore.
The Arabidopsis immune adaptor SRFR1 interacts with TCP transcription factors that redundantly contribute to effector‐triggered immunity
Authors: Kim Sang Hee , Son Geon Hui , Bhattacharjee Saikat , Kim Hye Jin , Nam Ji Chul , Nguyen Phuong Dung T. , Hong Jong Chan , Gassmann Walter
Published: April 2014

The plant immune system must be tightly controlled both positively and negatively to maintain normal plant growth and health. We previously identified SUPPRESSOR OF rps4‐RLD1 (SRFR1) as a negative regulator specifically of effector‐triggered immunity. SRFR1 is localized in both a cytoplasmic microsomal compartment and in the nucleus. Its TPR domain has sequence similarity to TPR domains of transcriptional repressors in other organisms, suggesting that SRFR1 may negatively regulate effector‐triggered immunity via transcriptional control. We show here that excluding SRFR1 from the nucleus prevented complementation of the srfr1 phenotype. To identify transcription factors that interact with SRFR1, we screened an Arabidopsis transcription factor prey library by yeast two‐hybrid assay and isolated six class I members of the TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factor family. Specific interactions were verified in planta. Although single or double T‐DNA mutant tcp8, tcp14 or tcp15 lines were not more susceptible to bacteria expressing AvrRps4, the triple tcp8 tcp14 tcp15 mutant displayed decreased effector‐triggered immunity mediated by the resistance genes RPS2, RPS4, RPS6 and RPM1. In addition, expression of PATHOGENESIS‐RELATED PROTEIN2 was attenuated in srfr1‐4 tcp8‐1 tcp14‐5 tcp15‐3 plants compared to srfr1‐4 plants. To date, TCP transcription factors have been implicated mostly in developmental processes. Our data indicate that one function of a subset of TCP proteins is to regulate defense gene expression in antagonism to SRFR1, and suggest a mechanism for an intimate connection between plant development and immunity.
KNOX genes influence a gradient of fruit chloroplast development through regulation of GOLDEN2‐LIKE expression in tomato
Authors: Nadakuduti Satya Swathi , Holdsworth William L. , Klein Chelsey L. , Barry Cornelius S.
Published: April 2014

The chlorophyll content of unripe fleshy fruits is positively correlated with the nutrient content and flavor of ripe fruit. In tomato (Solanum lycopersicum) fruit, the uniform ripening (u) locus, which encodes a GOLDEN 2‐LIKE transcription factor (SlGLK2), influences a gradient of chloroplast development that extends from the stem end of the fruit surrounding the calyx to the base of the fruit. With the exception of the u locus, the factors that influence the formation of this developmental gradient are unknown. In this study, characterization and positional cloning of the uniform gray‐green (ug) locus of tomato reveals a thus far unknown role for the Class I KNOTTED1‐LIKE HOMEOBOX (KNOX) gene, TKN4, in specifying the formation of this chloroplast gradient. The involvement of KNOX in fruit chloroplast development was confirmed through characterization of the Curl (Cu) mutant, a dominant gain‐of‐function mutation of TKN2, which displays ectopic fruit chloroplast development that resembles SlGLK2 over‐expression. TKN2 and TKN4 act upstream of SlGLK2 and the related gene ARABIDOPSIS PSEUDO RESPONSE REGULATOR 2‐LIKE (SlAPRR2‐LIKE) to establish their latitudinal gradient of expression across developing fruit that leads to a gradient of chloroplast development. Class I KNOX genes typically influence plant morphology through maintenance of meristem activity, but this study identifies a role for TKN2 and TKN4 in specifically influencing chloroplast development in fruit but not leaves, suggesting that this fundamental process is differentially regulated in these two organs.
Risk assessment for transmission of variant Creutzfeldt‐Jakob disease by transfusion of red blood cells in the United States
Authors: Yang Hong , Gregori Luisa , Asher David M. , Epstein Jay S. , Anderson Steven A.
Published: April 2014

Background

Variant Creutzfeldt‐Jakob disease (vCJD) is transmitted by blood transfusion. To mitigate the risk of transfusion‐transmitted vCJD (TTvCJD), the US Food and Drug Administration has recommended deferral of potential at‐risk blood donors, but some risk remains. We describe a quantitative risk assessment to estimate residual, postdeferral TTvCJD risk in the United States.

Study Design and Methods

We assumed that certain US donors may have acquired vCJD infection through dietary exposure to the agent of bovine spongiform encephalopathy during time spent in the United Kingdom, France, and other countries in Europe. Because of uncertainties regarding the prevalence of vCJD in the United Kingdom, we used both low and high UK prevalence estimates as model inputs. The model estimated the risk of infection from a transfusion in year 2011 and the cumulative risk from 1980 through 2011. The model was validated by comparing the model predictions with reported cases of vCJD.

Results

Using the low UK prevalence estimate, the model predicted a mean risk of 1 in 134 million transfusions, zero TTvCJD infections acquired in the year 2011, and zero cumulative clinical TTvCJD cases for the period spanning 1980 to 2011. With the high UK prevalence estimate, the model predicted a mean risk of 1 in 480,000 transfusions, six infections for 2011, and nine cumulative clinical cases from 1980 to 2011.

Conclusions

Model validation exercises indicated that predictions based on the low prevalence estimate are more consistent with clinical cases actually observed to date, implying that the risk, while highly uncertain, is likely very small.
Immunosuppressants and alloimmunization against red blood cell transfusions
Authors: Zalpuri Saurabh , Evers Dorothea , Zwaginga Jaap Jan , Schonewille Henk , de Vooght Karen M.K. , le Cessie Saskia , van der Bom Johanna G.
Published: April 2014

Background

Patients receiving red blood cell (RBC) transfusions are at risk of developing alloantibodies against donor RBC antigens. The risk of alloimmunization is dependent on the number of units administered and patient's genetic predisposition, but has also been suggested to be modulated by a patient's clinical profile. Our aim was to examine whether immunosuppressants suppress the development of clinically relevant RBC antibodies.

Study Design and Methods

A two‐center case‐referent study was performed where case patients and control patients were sampled from all consecutive patients (17,750 patients) who had received their first and subsequent RBC transfusions in a 5‐year period in the study centers. Cases were all patients with a first detected RBC alloantibody preceded by negative antibody screens. Control patients were two‐to‐one matched to the case patients on the number of RBC transfusions. Logistic regression analysis was used to examine the association between immunosuppressant exposure and the subsequent occurrence of RBC alloimmunization.

Results

A total of 156 case patients and 312 control patients in the study received a median of six transfusions (interquartile range, 3‐11). Among the total study population, 207 patients received immunosuppressive therapy, with 142 patients receiving only corticosteroids, four receiving only other immunosuppressants, and 61 receiving both. The incidence of alloimmunization among patients using immunosuppressants was lower than among other patients receiving RBCs (adjusted relative rate, 0.55; 95% confidence interval, 0.34‐0.91).

Conclusion

Our findings support a considerably lower risk of alloimmunization with the use of immunosuppressive medications.
Case report of a transfusion‐associated hepatitis A infection
Authors: Hughes Jonathan A. , Fontaine Magali J. , Gonzalez Christopher L. , Layon Arlene G. , Goodnough Lawrence Tim , Galel Susan A.
Published: April 2014

Background

Documented transfusion‐associated hepatitis A (TAHA) is rare, and blood donors in the United States are not routinely screened for this infection. We report a case of TAHA associated with a donation made 8 days after a donor returned from a trip to South America.

Study Design and Methods

This is a review of donor and recipient records and a review of the literature.

Results

A donor developed symptoms of hepatitis 20 days after donation (28 days after returning from South America). The donor reported the illness 56 days after donation when contacted to schedule another visit. By this time, the red blood cell and frozen plasma components had been transfused. The recipient of the plasma, a 15‐month‐old female, tested positive for immunoglobulin M antibody to hepatitis A virus 43 days after transfusion. The recipient had displayed mild, nonspecific symptoms approximately 2 weeks after transfusion. Hospital infection control investigated the potential for further spread within the hospital because the recipient had been an inpatient for most of the posttransfusion period. The risk of transmission to other patients was determined to be negligible because the patient had been in isolation for other reasons. Family members, who included a health care professional, were counseled and offered prophylaxis.

Conclusion

TAHA may be underrecognized. This case was identified only because of a donor report at the time of recruitment. Asymptomatic donor viremia has been documented in plasma donors. Although TAHA rarely results in severe disease, the risk it creates of secondary transmission especially within the hospital setting is not inconsequential.
Nutritional management of acute pancreatitis in dogs and cats
Authors: Jensen Kristine B. , Chan Daniel L.
Published: April 2014

Objective

To review current and emerging nutritional approaches in the management of acute pancreatitis (AP) in people, dogs, and cats, and to provide a framework for further investigation in this field.

Data sources

Veterinary retrospective studies and reviews, human prospective clinical trials and reviews, and experimental animal studies focusing on nutritional management during AP.

Nutritional management is an important part of the treatment plan for patients with AP. In human medicine, the general approach for providing nutrition in patients with AP has changed in recent years and favors enteral over parenteral nutrition with an emphasis on early enteral nutrition (EN). Although there are limited data available, there is increasing evidence in the veterinary literature that supports the beneficial role of EN in AP and contradicts previous assumptions about poor tolerance to enteral feeding in this patient population. Parenteral nutrition may be appropriate alone or in combination with EN as a temporary measure in malnourished patients that do not tolerate adequate EN; however, enteral feeding should be attempted first in most cases. Immunonutrition is being investigated for its positive role in modulating pancreatic inflammation and improving gut barrier function in cases of human AP.

Conclusions

The nutritional management of veterinary patients with AP remains challenging. Based on clinical evidence in people, experimental animal studies, and preliminary studies in dogs and cats, the choice of EN over parenteral nutritional support during AP in dogs and cats appears to be beneficial and well tolerated. Optimization of nutritional therapies in dogs and cats including the use of immunonutrition during AP warrants further investigation.
CD4+ T cells enhance the unloaded shortening velocity of airway smooth muscle by altering the contractile protein expression
Authors: Matusovsky Oleg S. , Nakada Emily M. , Kachmar Linda , Fixman Elizabeth D. , Lauzon Anne‐Marie
Published: April 2014

Key points

Activated CD4+ T cells enhance the contractility of airway smooth muscle.

In order to enhance contractility, contact between CD4+ T cells and smooth muscle is required.

The enhanced contractility is correlated with increased levels of fast myosin isoform.

Our data suggest that inflammatory cells promote airway smooth muscle hypercontractility in airway hyper‐responsiveness and asthma.

Abundant data indicate that pathogenesis in allergic airways disease is orchestrated by an aberrant T‐helper 2 (Th2) inflammatory response. CD4+ T cells have been localized to airway smooth muscle (ASM) in both human asthmatics and in rodent models of allergic airways disease, where they have been implicated in proliferative responses of ASM. Whether CD4+ T cells also alter ASM contractility has not been addressed. We established an in vitro system to assess the ability of antigen‐stimulated CD4+ T cells to modify contractile responses of the Brown Norway rat trachealis muscle. Our data demonstrated that the unloaded velocity of shortening (Vmax) of ASM was significantly increased upon 24 h co‐incubation with antigen‐stimulated CD4+ T cells, while stress did not change. Enhanced Vmax was dependent upon contact between the CD4+ T cells and the ASM and correlated with increased levels of the fast (+)insert smooth muscle myosin heavy chain isoform. The levels of myosin light chain kinase and myosin light chain phosphorylation were also increased within the muscle. The alterations in mechanics and in the levels of contractile proteins were transient, both declining to control levels after 48 h of co‐incubation. More permanent alterations in muscle phenotype might be attainable when several inflammatory cells and mediators interact together or after repeated antigenic challenges. Further studies will await new tissue culture methodologies that preserve the muscle properties over longer periods of time. In conclusion, our data suggest that inflammatory cells promote ASM hypercontractility in airway hyper‐responsiveness and asthma.
Fibre type‐specific satellite cell response to aerobic training in sedentary adults
Authors: Fry Christopher S. , Noehren Brian , Mula Jyothi , Ubele Margo F. , Westgate Philip M. , Kern Philip A. , Peterson Charlotte A.
Published: April 2014

Key points

Satellite cell activation and fusion accompany resistance exercise training.

Aerobic exercise training is capable of inducing subtle muscle fibre hypertrophy; however, the role of satellite cell activation during aerobic exercise‐induced muscle adaptation is unknown.

Twelve weeks of aerobic training in sedentary subjects yielded an increase in myosin heavy chain type I and type II muscle fibre cross‐sectional area.

Satellite cell activation and myonuclear addition occurred only in myosin heavy chain type I fibres, with no change in myosin heavy chain type II fibres.

These results help us better understand the role of satellite cells in muscle fibre adaptation to aerobic exercise, and suggest differential fibre type regulation of the myonuclear domain.

In the present study, we sought to determine the effect of a traditional, 12 week aerobic training protocol on skeletal muscle fibre type distribution and satellite cell content in sedentary subjects. Muscle biopsies were obtained from the vastus lateralis [n = 23 subjects (six male and 17 female); body mass index 30.7 ± 1.2 kg m−2] before and after 12 weeks of aerobic training performed on a cycle ergometer. Immunohistochemical analyses were used to quantify myosin heavy chain (MyHC) isoform expression, cross‐sectional area and satellite cell and myonuclear content. Following training, a decrease in MyHC hybrid type IIa/IIx fibre frequency occurred, with a concomitant increase in pure MyHC type IIa fibres. Pretraining fibre type correlated with body mass index, and the change in fibre type following training was associated with improvements in maximal oxygen consumption. Twelve weeks of aerobic training also induced increases in mean cross‐sectional area in both MyHC type I and type IIa fibres. Satellite cell content was also increased following training, specifically in MyHC type I fibres, with no change in the number of satellite cells associated with MyHC type II fibres. With the increased satellite cell content following training, an increase in myonuclear number per fibre also occurred in MyHC type I fibres. Hypertrophy of MyHC type II fibres occurred without detectable myonuclear addition, suggesting that the mechanisms underlying growth in fast and slow fibres differ. These data provide intriguing evidence for a fibre type‐specific role of satellite cells in muscle adaptation following aerobic training.
Polycystins and partners: proposed role in mechanosensitivity
Authors: Retailleau Kevin , Duprat Fabrice
Published: April 2014

Mutations of the two polycystins, PC1 and PC2, lead to polycystic kidney disease. Polycystins are able to form complexes with numerous families of proteins that have been suggested to participate in mechanical sensing. The proposed role of polycystins and their partners in the kidney primary cilium is to sense urine flow. A role for polycystins in mechanosensing has also been shown in other cell types such as vascular smooth muscle cells and cardiac myocytes. At the plasma membrane, polycystins interact with diverse ion channels of the TRP family and with stretch‐activated channels (Piezos, TREKs). The actin cytoskeleton and its interacting proteins, such as filamin A, have been shown to be essential for these interactions. Numerous proteins involved in cell–cell and cell–extracellular matrix junctions interact with PC1 and/or PC2. These multimeric protein complexes are important for cell structure integrity, the transmission of force, as well as for mechanosensing and mechanotransduction. A group of polycystin partners are also involved in subcellular trafficking mechanisms. Finally, PC1 and especially PC2 interact with elements of the endoplasmic reticulum and are essential components of calcium homeostasis. In conclusion, we propose that both PC1 and PC2 act as conductors to tune the overall cellular mechanosensitivity.