bluuebunny/crossref_metadata_2025 huggingface dataset:
Neighborhood Sectarian Displacement and the Battle for Baghdad: A Self‐Fulfilling Prophecy of Fear and Crimes Against Humanity in Iraq
Authors: Hagan John , Kaiser Joshua , Hanson Anna , Parker Patricia
Published: March 2015

We use two unique Iraq data sets to show how fear and uncertainty served to motivate the self‐fulfilling, neighborhood‐specific forces that followed the U.S.‐led invasion of Iraq. Sectarian criminal violence by armed Shia and Sunni organizations created a situation of ethnic/religious cleansing that reconfigured much of Baghdad. The article focuses on the case of how one particularly violent group, the Mahdi Army, mobilized through the coercive entrepreneurship of Muqtada al‐Sadr, used organized crime tactics of killing, torture, rape, kidnapping, harassment, threats, and forced displacement in a widespread and systematic attack against civilians that forced Sunni residents from their Baghdad neighborhoods. Ordinary Iraqis were victims of an amplified “self‐fulfilling prophecy of fear” that created the momentum for massive sectarian displacement in the battle for Baghdad. We demonstrate that there is a neighborhood specific effect of early postinvasion neighborhood fear net of intervening violence on displacement three years later, following the Al‐Qaeda Samara Shrine attack, confirming an effect of a self‐fulfilling prophecy of fear in the neighborhoods of Baghdad that compounded in a self‐reinforcing way. The changed demography of Baghdad was effectively consolidated by the later surge of U.S. forces that left in place the territorial gains made by the Shia‐led Mahdi Army at the expense of former Sunni residents. We conclude that this continues to matter because the resulting grievances have contributed to renewed violence.
Assets and Affect in the Study of Social Capital in Rural Communities
Authors: Phillips Martin
Published: March 2015

Shucksmith (2012) has recently suggested that rural research might be refreshed by incorporating theoretical insights that have emerged through a renewal of class analysis. This article seeks to advance this proposed research agenda by exploring the concept of asset‐based class analysis and its association with the concept of social capital. The article explores connections between social capital, class analysis and understandings of community, noting how all have been associated with long running and unresolved debates. Attention is drawn to the problems of modernist legislative approaches to these debates and the value of adopting more interpretive perspectives. A distinction between ‘infrastructural’ and ‘culturalist’ interpretations of social capital is explored in relation to ‘asset‐based’ theorisations of class and culture. It is argued that an infrastructural conception of social capital might usefully be employed in association with a disaggregated conception of cultural capital that includes consideration of emotion and affect, as well as institutional, objectified and technical assets. These arguments are explored using studies of rural communities, largely within Britain.
Mycobacterium abscessus pulmonary infection complicated with vertebral osteomyelitis in a heart transplant recipient: case report and literature review
Authors: Silva J.T. , López‐Medrano F. , Fernández‐Ruiz M. , San‐Juan R. , Ruiz‐Cano M.J. , Delgado J.F. , Aguado J.M.
Published: March 2015

Infections produced by Mycobacterium abscessus are emerging in immunosuppressed patients, such as solid organ transplant recipients. We report the first case, to our knowledge, of a vertebral osteomyelitis caused by M. abscessus in a heart transplant recipient, and review the risk factors, manifestations, and therapeutic approaches to this uncommon disease.
Search and the Aging Mind: The Promise and Limits of the Cognitive Control Hypothesis of Age Differences in Search
Authors: Mata Rui , von Helversen Bettina
Published: March 2015

Search is a prerequisite for successful performance in a broad range of tasks ranging from making decisions between consumer goods to memory retrieval. How does aging impact search processes in such disparate situations? Aging is associated with structural and neuromodulatory brain changes that underlie cognitive control processes, which in turn have been proposed as a domain‐general mechanism controlling search in external environments as well as memory. We review the aging literature to evaluate the cognitive control hypothesis that suggests that age‐related change in cognitive control underlies age differences in both external and internal search. We also consider the limits of the cognitive control hypothesis and propose additional mechanisms such as changes in strategy use and affect that may be necessary to understand how aging affects search.
Transitions to religious adulthood: relational geographies of youth, religion and international volunteering
Authors: Hopkins Peter , Olson Elizabeth , Baillie Smith Matt , Laurie Nina
Published: March 2015

This paper offers important insights into the contemporary nature of youth transitions and the ways in which religious affiliation and engagement with international volunteering influences and interplays with negotiations of the life course. Situated within interdisciplinary debates about youth transitions, as well as discussions about relational geographies of age, religion and voluntarism, we demonstrate the multiple relationalities that are at play as young religious international volunteers negotiate the transition to religious adulthood. We focus on religious, vocational and aged relationalities to explore how these are engaged with, and experienced by, young people ‘over there’ in Latin America and ‘back home’ in theUK. Additionally, we explore how these relationalities shape identities within and between religiosity, age (youth) and volunteering, and how these are (re)organised through networks, flows and mobilities. To do so, we draw on our analysis of the experiences of young volunteers who participated in faith‐based international volunteering with an evangelical Christian organisation that sends teams of young people on short‐term missions to Latin America. We draw on our analyses of two sets of interviews with 22 young volunteers, 14 of whom also completed a diary about their experiences, supplemented by four focus groups. Our analysis points to the ways in which the spatial emphasis of geographical engagements with youth transitions can be well informed through considerations of religion; a key challenge being how young volunteers renegotiate their sense of religious self on returning ‘back home’. In addition, although our participants displayed some self‐reflexivity about the social construction of age, they did not necessarily exhibit an understanding of the power underpinning their encounters with others. Finally, our findings open up possibilities for appreciating the diversity of volunteering experiences and the role that volunteer organisations have in shaping the expectations and aspirations of those who participate in their programmes.
Rapid enzyme analysis as a diagnostic tool for wound infection: Comparison between clinical judgment, microbiological analysis, and enzyme analysis
Authors: Blokhuis‐Arkes Miriam H.E. , Haalboom Marieke , van der Palen Job , Heinzle Andrea , Sigl Eva , Guebitz Georg , Beuk Roland
Published: March 2015

In clinical practice, diagnosis of wound infection is based on the classical clinical signs of infection. When infection is suspected, wounds are often swabbed for microbiological culturing. These methods are not accurate (clinical judgment in chronic wounds) or provide results after several days (wound swab). Therefore, there is an urgent need for an easy‐to‐use diagnostic tool for fast detection of wound infection, especially in chronic wounds. This study determined the diagnostic properties of the enzymes myeloperoxidase, human neutrophil elastase (HNE), lysozyme and cathepsin‐G in detecting wound infection when compared to wound swabs. Both chronic and acute wounds of 81 patients were assessed through clinical judgment, enzyme analysis and wound swab. Three promising enzyme models for detecting wound infection were identified. A positive test was defined as: at least one enzyme positive after 30 minutes (model 1), lysozyme and HNE positive after 30 minutes (model 2), myeloperoxidase positive after 5 minutes, and HNE or lysozyme positive after 30 minutes (model 3). All models were significant (p≤0.001). There was no correlation between clinical judgment and wound swab, indicating the need for novel diagnostic systems. Enzyme analysis is fast, easy to use and superior to clinical judgment when compared to wound swabs.
Exercise training and return to a well‐balanced diet activate the neuregulin 1/ErbB pathway in skeletal muscle of obese rats
Authors: Ennequin Gaël , Boisseau Nathalie , Caillaud Kevin , Chavanelle Vivien , Gerbaix Maude , Metz Lore , Etienne Monique , Walrand Stéphane , Masgrau Aurélie , Guillet Christelle , Courteix Daniel , Niu Airu , Li Yi‐Ping , Capel Fréderic , Sirvent Pascal
Published: March 2015

Key points

Some studies suggest that neuregulin 1 (NRG1) could be involved in the regulation of skeletal muscle energy metabolism in rodents.

Here we assessed whether unbalanced diet is associated with alterations of the NRG1 signalling pathway and whether exercise and diet might restore NRG1 signalling in skeletal muscle of obese rats.

We show that diet‐induced obesity does not impair NRG1 signalling in rat skeletal muscle.

We also report that endurance training and a well‐balanced diet activate the NRG1 signalling in skeletal muscle of obese rats, possibly via a new mechanism mediated by the protease ADAM17.

These results suggest that some beneficial effects of physical activity and diet in obese rats could be partly explained by stimulation of the NRG1 signalling pathway.

Some studies suggest that the signalling pathway of neuregulin 1 (NRG1), a protein involved in the regulation of skeletal muscle metabolism, could be altered by nutritional and exercise interventions. We hypothesized that diet‐induced obesity could lead to alterations of the NRG1 signalling pathway and that chronic exercise could improve NRG1 signalling in rat skeletal muscle. To test this hypothesis, male Wistar rats received a high fat/high sucrose (HF/HS) diet for 16 weeks. At the end of this period, NRG1 and ErbB expression/activity in skeletal muscle was assessed. The obese rats then continued the HF/HS diet or were switched to a well‐balanced diet. Moreover, in both groups, half of the animals also performed low intensity treadmill exercise training. After another 8 weeks, NRG1 and ErbB expression/activity in skeletal muscle were tested again. The 16 week HF/HS diet induced obesity, but did not significantly affect the NRG1/ErbB signalling pathway in rat skeletal muscle. Conversely, after the switch to a well‐balanced diet, NRG1 cleavage ratio and ErbB4 amount were increased. Chronic exercise training also promoted NRG1 cleavage, resulting in increased ErbB4 phosphorylation. This result was associated with increased protein expression and phosphorylation ratio of the metalloprotease ADAM17, which is involved in NRG1 shedding. Similarly, in vitro stretch‐induced activation of ADAM17 in rat myoblasts induced NRG1 cleavage and ErbB4 activation. These results show that low intensity endurance training and well‐balanced diet activate the NRG1‐ErbB4 pathway, possibly via the metalloprotease ADAM17, in skeletal muscle of diet‐induced obese rats.
State‐dependent control of breathing by the retrotrapezoid nucleus
Authors: Burke Peter G.R. , Kanbar Roy , Basting Tyler M. , Hodges Walter M. , Viar Kenneth E. , Stornetta Ruth L. , Guyenet Patrice G.
Published: March 2015

Key points

This study explores the state dependence of the hypercapnic ventilatory reflex (HCVR). We simulated an instantaneous increase or decrease of central chemoreceptor activity by activating or inhibiting the retrotrapezoid nucleus (RTN) by optogenetics in conscious rats.

During quiet wake or non‐REM sleep, hypercapnia increased both breathing frequency (fR) and tidal volume (VT) whereas, in REM sleep, hypercapnia increased VT exclusively.

Optogenetic inhibition of RTN reduced VT in all sleep–wake states, but reduced fR only during quiet wake and non‐REM sleep. RTN stimulation always increased VT but raised fR only in quiet wake and non‐REM sleep.

Phasic RTN stimulation produced active expiration and reduced early expiratory airflow (i.e. increased upper airway resistance) only during wake.

We conclude that the HCVR is highly state‐dependent. The HCVR is reduced during REM sleep because fR is no longer under chemoreceptor control and thus could explain why central sleep apnoea is less frequent in REM sleep.

Breathing has different characteristics during quiet wake, non‐REM or REM sleep, including variable dependence on . We investigated whether the retrotrapezoid nucleus (RTN), a proton‐sensitive structure that mediates a large portion of the hypercapnic ventilatory reflex, regulates breathing differently during sleep vs. wake. Electroencephalogram, neck electromyogram, blood pressure, respiratory frequency (fR) and tidal volume (VT) were recorded in 28 conscious adult male Sprague–Dawley rats. Optogenetic stimulation of RTN with channelrhodopsin‐2, or inhibition with archaerhodopsin, simulated an instantaneous increase or decrease of central chemoreceptor activity. Both opsins were delivered with PRSX8‐promoter‐containing lentiviral vectors. RTN and catecholaminergic neurons were transduced. During quiet wake or non‐REM sleep, hypercapnia (3 or 6% ) increased both fR and VT whereas, in REM sleep, hypercapnia increased VT exclusively. RTN inhibition always reduced VT but reduced fR only during quiet wake and non‐REM sleep. RTN stimulation always increased VT but raised fR only in quiet wake and non‐REM sleep. Blood pressure was unaffected by either stimulation or inhibition. Except in REM sleep, phasic RTN stimulation entrained and shortened the breathing cycle by selectively shortening the post‐inspiratory phase. Phasic stimulation also produced active expiration and reduced early expiratory airflow but only during wake. VT is always regulated by RTN and CO2 but fR is regulated by CO2 and RTN only when the brainstem pattern generator is in autorhythmic mode (anaesthesia, non‐REM sleep, quiet wake). The reduced contribution of RTN to breathing during REM sleep could explain why certain central apnoeas are less frequent during this sleep stage.
Chloride transporters and receptor‐mediated endocytosis in the renal proximal tubule
Authors: Devuyst Olivier , Luciani Alessandro
Published: March 2015

Key points

The reabsorptive activity of renal proximal tubule cells is mediated by receptor‐mediated endocytosis and polarized transport systems that reflect final cell differentiation.

Loss‐of‐function mutations of the endosomal chloride–proton exchanger ClC‐5 (Dent's disease) cause a major trafficking defect in proximal tubule cells, associated with lysosomal dysfunction, oxidative stress and dedifferentiation/proliferation.

A similar but milder defect is associated with mutations in CFTR (cystic fibrosis transmembrane conductance regulator).

Vesicular chloride transport appears to be important for the integrity of the endolysosomal pathway in epithelial cells.

The epithelial cells lining the proximal tubules of the kidney reabsorb a large amount of filtered ions and solutes owing to receptor‐mediated endocytosis and polarized transport systems that reflect final cell differentiation. Dedifferentiation of proximal tubule cells and dysfunction of receptor‐mediated endocytosis characterize Dent's disease, a rare disorder caused by inactivating mutations in the CLCN5 gene that encodes the endosomal chloride–proton exchanger, ClC‐5. The disease is characterized by a massive urinary loss of solutes (renal Fanconi syndrome), with severe metabolic complications and progressive renal failure. Investigations of mutations affecting the gating of ClC‐5 revealed that the proximal tubule dysfunction may occur despite normal endosomal acidification. In addition to defective endocytosis, proximal tubule cells lacking ClC‐5 show a trafficking defect in apical receptors and transporters, as well as lysosomal dysfunction and typical features of dedifferentiation, proliferation and oxidative stress. A similar but milder defect is observed in mouse models with defective CFTR, a chloride channel that is also expressed in the endosomes of proximal tubule cells. These data suggest a major role for endosomal chloride transport in the maintenance of epithelial differentiation and reabsorption capacity of the renal proximal tubule.
Getting to the heart of hERG K+ channel gating
Authors: Perry Matthew D. , Ng Chai‐Ann , Mann Stefan A. , Sadrieh Arash , Imtiaz Mohammad , Hill Adam P. , Vandenberg Jamie I.
Published: March 2015

Potassium ion channels encoded by the human ether‐a‐go‐go related gene (hERG) form the ion‐conducting subunit of the rapid delayed rectifier potassium current (IKr). Although hERG channels exhibit a widespread tissue distribution they play a particularly important role in the heart. There has been considerable interest in hERG K+ channels for three main reasons. First, they have very unusual gating kinetics, most notably rapid and voltage‐dependent inactivation coupled to slow deactivation, which has led to the suggestion that they may play a specific role in the suppression of arrhythmias. Second, mutations in hERG are the cause of 30–40% of cases of congenital long QT syndrome (LQTS), the commonest inherited primary arrhythmia syndrome. Third, hERG is the molecular target for the vast majority of drugs that cause drug‐induced LQTS, the commonest cause of drug‐induced arrhythmias and cardiac death. Drug‐induced LQTS has now been reported for a large range of both cardiac and non‐cardiac drugs, in which this side effect is entirely undesired. In recent years there have been comprehensive reviews published on hERG K+ channels (Vandenberg et al. 2012) and we will not re‐cover this ground. Rather, we focus on more recent work on the structural basis and dynamics of hERG gating with an emphasis on how the latest developments may facilitate translational research in the area of stratifying risk of arrhythmias.
Organization of left–right coordination of neuronal activity in the mammalian spinal cord: Insights from computational modelling
Authors: Shevtsova Natalia A. , Talpalar Adolfo E. , Markin Sergey N. , Harris‐Warrick Ronald M. , Kiehn Ole , Rybak Ilya A.
Published: March 2015

Key points

Coordination of neuronal activity between left and right sides of the mammalian spinal cord is provided by several sets of commissural interneurons (CINs) whose axons cross the midline. Genetically identified inhibitory V0D and excitatory V0V CINs and ipsilaterally projecting excitatory V2a interneurons were shown to secure left–right alternation at different locomotor speeds.

We have developed computational models of neuronal circuits in the spinal cord that include left and right rhythm‐generating centres interacting bilaterally via three parallel pathways mediated by V0D, V2a–V0V and V3 neuron populations.

The models reproduce the experimentally observed speed‐dependent left–right coordination in normal mice and the changes in coordination seen in mutants lacking specific neuron classes.

The models propose an explanation for several experimental results and provide insights into the organization of the spinal locomotor network and parallel CIN pathways involved in gait control at different locomotor speeds.

Different locomotor gaits in mammals, such as walking or galloping, are produced by coordinated activity in neuronal circuits in the spinal cord. Coordination of neuronal activity between left and right sides of the cord is provided by commissural interneurons (CINs), whose axons cross the midline. In this study, we construct and analyse two computational models of spinal locomotor circuits consisting of left and right rhythm generators interacting bilaterally via several neuronal pathways mediated by different CINs. The CIN populations incorporated in the models include the genetically identified inhibitory (V0D) and excitatory (V0V) subtypes of V0 CINs and excitatory V3 CINs. The model also includes the ipsilaterally projecting excitatory V2a interneurons mediating excitatory drive to the V0V CINs. The proposed network architectures and CIN connectivity allow the models to closely reproduce and suggest mechanistic explanations for several experimental observations. These phenomena include: different speed‐dependent contributions of V0D and V0V CINs and V2a interneurons to left–right alternation of neural activity, switching gaits between the left–right alternating walking‐like activity and the left–right synchronous hopping‐like pattern in mutants lacking specific neuron classes, and speed‐dependent asymmetric changes of flexor and extensor phase durations. The models provide insights into the architecture of spinal network and the organization of parallel inhibitory and excitatory CIN pathways and suggest explanations for how these pathways maintain alternating and synchronous gaits at different locomotor speeds. The models propose testable predictions about the neural organization and operation of mammalian locomotor circuits.
Effects of Free Surface Evaporation on Water Nanodroplet Wetting Kinetics: A Molecular Dynamics Study
Authors: Lu Gui , Duan Yuan-Yuan , Wang Xiao-Dong
Published: March 2015

The wetting kinetics of a water nanodroplet undergoing evaporation on a heated gold substrate were examined using molecular dynamics (MD) simulations. Various substrate and initial droplet temperatures were used to obtain different evaporation rates. The water molecule absorption–desorption behavior was analyzed in the vicinity of the contact line region to show the microscopic details of the spreading–evaporating droplet. Increasing substrate temperatures greatly affected the dynamic wetting process, while the initial water droplet temperature had very little effect. The effects of droplet size and substrate wettability on the droplet spreading–evaporating process were also examined. The radius versus time curves agree well with molecular kinetics theory (MKT) for spreading without evaporation but differ from MKT when the spreading induced evaporation. The enhancement of the wetting kinetics by the evaporation can be attributed to the reduction of the liquid–vapor surface tension and the increased water molecule motion in the contact line region and in the bulk droplet.
Film Thickness and Rolling Resistance in Starved Elastohydrodynamic Lubrication of Point Contacts With Reflow
Authors: Nogi Takashi
Published: March 2015

Elastohydrodynamic lubrication (EHL) film thickness and rolling resistance play a critical role in determining friction, wear, life, and other tribological characteristics of rolling bearings. Although film thickness formulas are widely used and experimentally verified, accurate prediction of the film thickness is still difficult under starved conditions. This paper presents a numerical study of starved EHL point contacts using a nonuniform inlet film thickness obtained from a modified Coyne–Elrod boundary condition. An experimental verification of the numerical results is also presented. Based on the results of a parametric study, inlet distance formulas are obtained as a function of the initial film thickness, the fully flooded central film thickness, and the capillary number. By using the inlet distance formulas and the Hamrock–Dowson formulas, the central film thickness, the minimum film thickness, and the viscous rolling resistance can be calculated.
Enhanced Mass Transfer Rates in Nanofluids: Experiments and Modeling
Authors: Khanolkar Ratnesh U. , Suresh A. K.
Published: March 2015

Enhancement in carbon dioxide absorption in water has been studied using SiO2 and TiO2 nanoparticles using the capillary tube apparatus for which previous results on Fe3O4 nanoparticles were reported earlier. Enhancements of up to 165% in the mass transfer coefficients were observed at fairly low volume fractions of the particles. A model which accounts for the effect of particles in terms of a superimposed convection has been proposed to explain the observed effects of particle size, hold-up, and material density. The model provides a good fit to the data from wetted wall column and capillary tube experiment for Fe3O4 from the previous literature, as well as for the data from this work.
Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques
Authors: Hernandez V. , Abella R. , Calvo J. F. , Jurado‐Bruggemann D. , Sancho I. , Carrasco P.
Published: March 2015

Purpose:

Several authors have recommended a 2 mm tolerance for multileaf collimator (MLC) positioning in sliding window treatments. In volumetric modulated arc therapy (VMAT) treatments, however, the optimal tolerance for MLC positioning remains unknown. In this paper, the authors present the results of a multicenter study to determine the optimal tolerance for both techniques.

Methods:

The procedure used is based on dynalog file analysis. The study was carried out using seven Varian linear accelerators from five different centers. Dynalogs were collected from over 100 000 clinical treatments and in‐house software was used to compute the number of tolerance faults as a function of the user‐defined tolerance. Thus, the optimal value for this tolerance, defined as the lowest achievable value, was investigated.

Results:

Dynalog files accurately predict the number of tolerance faults as a function of the tolerance value, especially for low fault incidences. All MLCs behaved similarly and the Millennium120 and the HD120 models yielded comparable results. In sliding window techniques, the number of beams with an incidence of hold‐offs >1% rapidly decreases for a tolerance of 1.5 mm. In VMAT techniques, the number of tolerance faults sharply drops for tolerances around 2 mm. For a tolerance of 2.5 mm, less than 0.1% of the VMAT arcs presented tolerance faults.

Conclusions:

Dynalog analysis provides a feasible method for investigating the optimal tolerance for MLC positioning in dynamic fields. In sliding window treatments, the tolerance of 2 mm was found to be adequate, although it can be reduced to 1.5 mm. In VMAT treatments, the typically used 5 mm tolerance is excessively high. Instead, a tolerance of 2.5 mm is recommended.
Lung dynamic MRI deblurring using low‐rank decomposition and dictionary learning
Authors: Gou Shuiping , Wang Yueyue , Wu Jiaolong , Lee Percy , Sheng Ke
Published: March 2015

Purpose:

Lung dynamic MRI (dMRI) has emerged to be an appealing tool to quantify lung motion for both planning and treatment guidance purposes. However, this modality can result in blurry images due to intrinsically low signal‐to‐noise ratio in the lung and spatial/temporal interpolation. The image blurring could adversely affect the image processing that depends on the availability of fine landmarks. The purpose of this study is to reduce dMRI blurring using image postprocessing.

Methods:

To enhance the image quality and exploit the spatiotemporal continuity of dMRI sequences, a low‐rank decomposition and dictionary learning (LDDL) method was employed to deblur lung dMRI and enhance the conspicuity of lung blood vessels. Fifty frames of continuous 2D coronal dMRI frames using a steady state free precession sequence were obtained from five subjects including two healthy volunteer and three lung cancer patients. In LDDL, the lung dMRI was decomposed into sparse and low‐rank components. Dictionary learning was employed to estimate the blurring kernel based on the whole image, low‐rank or sparse component of the first image in the lung MRI sequence. Deblurring was performed on the whole image sequences using deconvolution based on the estimated blur kernel. The deblurring results were quantified using an automated blood vessel extraction method based on the classification of Hessian matrix filtered images. Accuracy of automated extraction was calculated using manual segmentation of the blood vessels as the ground truth.

Results:

In the pilot study, LDDL based on the blurring kernel estimated from the sparse component led to performance superior to the other ways of kernel estimation. LDDL consistently improved image contrast and fine feature conspicuity of the original MRI without introducing artifacts. The accuracy of automated blood vessel extraction was on average increased by 16% using manual segmentation as the ground truth.

Conclusions:

Image blurring in dMRI images can be effectively reduced using a low‐rank decomposition and dictionary learning method using kernels estimated by the sparse component.
Monte Carlo simulation of PET and SPECT imaging of 90Y
Authors: Takahashi Akihiko , Himuro Kazuhiko , Yamashita Yasuo , Komiya Isao , Baba Shingo , Sasaki Masayuki
Published: March 2015

Purpose:

Yittrium‐90 (90Y) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single‐photon emission computed tomography (SPECT). However, because 90Y also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of 90Y bremsstrahlung SPECT, PET imaging has been suggested as an alternative. In this paper, the authors present the Monte Carlo‐based simulation–reconstruction framework for 90Y to comprehensively analyze the PET and SPECT imaging techniques and to quantitatively consider the disadvantages associated with them.

Methods:

Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP‐PET) generates a sinogram, and reconstructs the tomography image using a time‐of‐flight ordered subset expectation maximization (TOF‐OSEM) algorithm with attenuation compensation. To evaluate MCEP‐PET, simulated results of 18F PET imaging were compared with the experimental results. The results confirmed that MCEP‐PET can simulate the experimental results very well. The SPECT code (MCEP‐SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded 90Y bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of 90Y without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min.

Results:

The simulated 90Y‐PET image accurately simulated the experimental results. PET image is visually superior to SPECT image because of the low background noise. The simulation reveals that the detected photon number in SPECT is comparable to that of PET, but the large fraction (approximately 75%) of scattered and penetration photons contaminates SPECT image. The lower limit of 90Y detection in SPECT image was approximately 200 kBq/ml, while that in PET image was approximately 100 kBq/ml.

Conclusions:

By comparing the background noise level and the image concentration profile of both the techniques, PET image quality was determined to be superior to that of bremsstrahlung SPECT. The developed simulation codes will be very useful in the future investigations of PET and bremsstrahlung SPECT imaging of 90Y.
Acute Beetroot Juice Supplementation Does Not Improve Cycling Performance in Normoxia or Moderate Hypoxia
Authors: MacLeod Kristin E. , Nugent Sean F. , Barr Susan I. , Koehle Michael S. , Sporer Benjamin C. , MacInnis Martin J.
Published: March 2015

Beetroot juice (BR) has been shown to lower the oxygen cost of exercise in normoxia and may have similar effects in hypoxia. We investigated the effect of BR on steady-state exercise economy and 10-km time trial (TT) performance in normoxia and moderate hypoxia (simulated altitude: ~2500 m). Eleven trained male cyclists (VO2peak ≥ 60 ml·kg-1·min-1) completed four exercise trials. Two hours before exercise, subjects consumed 70 mL BR (~6 mmol nitrate) or placebo (nitrate-depleted BR) in a randomized, double-blind manner. Subjects then completed a 15-min self-selected cycling warm-up, a 15-min steady-state exercise bout at 50% maximum power output, and a 10-km time trial (TT) in either normoxia or hypoxia. Environmental conditions were randomized and single-blind. BR supplementation increased plasma nitrate concentration and fraction of exhaled nitric oxide relative to PL (p < .05 for both comparisons). Economy at 50% power output was similar in hypoxic and normoxic conditions (p > .05), but mean power output was greater in the normoxic TT relative to the hypoxic TT (p < .05). BR did not affect economy, steady-state SpO2, mean power output, or 10-km TT completion time relative to placebo in either normoxia or hypoxia (p > .05 in all comparisons). In conclusion, BR did not lower the oxygen cost of steady-state exercise or improve exercise performance in normoxia or hypoxia in a small sample of well-trained male cyclists.
Nutritional Supplement Habits of Athletes With an Impairment and Their Sources of Information
Authors: Graham-Paulson Terri Susan , Perret Claudio , Smith Brett , Crosland Jeanette , Goosey-Tolfrey Victoria Louise
Published: March 2015

The consumption of nutritional supplements (NS) is common among able-bodied (AB) athletes yet little is known about NS use by athletes with an impairment. This study examined the: (i) prevalence of NS use by athletes with an impairment; (ii) reasons for use/nonuse; (iii) sources of information regarding NS; and (iv) whether age, gender, impairment, performance level and sport category influence NS use. The questionnaire was completed by 399 elite (n = 255) and nonelite (n = 144) athletes (296 M, 103 F) online or at a sporting event/training camp. Data were evaluated using chi-square analyses. Fifty-eight percent (n = 232) of athletes used NS in the previous 6-month period and 41% (n = 102) of these followed the instructions on the label to determine dose. Adherence to these AB recommendations may partly explain why 9% (n = 37) experienced negative effects from NS use. As expected, the most popular NS were: protein, sports drinks, multivitamins and carbohydrate supplements, which were obtained from health food/sport shops, internet and supermarkets (top 3) where evidence-based, impairment-specific advice is limited. The nutritionist/dietitian was the most used and trusted source of information, which is a promising finding. The most prevalent reasons for use were to support exercise recovery, support the immune system and provide energy. Elite athletes were more likely to use NS, which may reflect greater training hours and/or access to nutritionists. Fifty-two percent of athletes (n = 209) requested more information/education regarding NS. NS use is prevalent in this population. Education on dosage and appropriate sources of information is required.
Ingesting Isomaltulose Versus Fructose-Maltodextrin During Prolonged Moderate-Heavy Exercise Increases Fat Oxidation but Impairs Gastrointestinal Comfort and Cycling Performance
Authors: Oosthuyse Tanja , Carstens Matthew , Millen Aletta M.E.
Published: March 2015

Certain commercial carbohydrate replacement products include slowly absorbed carbohydrates such as isomaltulose. Few studies have investigated the metabolic effects of ingesting isomaltulose during exercise and none have evaluated exercise performance and gastrointestinal comfort. Nine male cyclists participated postprandially during three trials of 2-h steady-state (S-S) exercise (60% Wmax) followed by a 16 km time trial (TT) while ingesting 63 g∙h-1 of either, 0.8:1 fructose: maltodextrin (F:M) or isomaltulose (ISO) or placebo-flavored water (PL). Data were analyzed by magnitude-based inferences. During S-S exercise, ISO and PL similarly increased plasma nonesterified fatty acid (NEFA) concentration (mean change ISO versus F:M: 0.18, 90%CI ± 0.21 mmol∙L-1, 88% likelihood) and fat oxidation (10, 90%CI ± 9 g, 89% likelihood) while decreasing carbohydrate oxidation (-36, 90%CI ± 30.2 g, 91% likelihood) compared with F:M, despite equal elevations in blood glucose concentration with ISO and F:M. Rating of stomach cramps and bloating increased progressively with ISO (rating: 0-90 min S-S, weak; 120 min S-S, moderate; TT, strong) compared with F:M and PL (0-120 min S-S and TT, very weak). TT performance was substantially slower with ISO (mean change: 1.5, 90%CI ± 1.4 min, 94% likely harmful) compared with F:M. The metabolic response of ISO ingestion during moderate exercise to increase NEFA availability and fat oxidation despite elevating blood glucose concentration is anomalous for a carbohydrate supplement. However, ingesting isomaltulose at a continuous high frequency to meet the recommended carbohydrate replacement dose, results in severe gastrointestinal symptoms during prolonged or high intensity exercise and negatively affects exercise performance compared with fructose-maltodextrin supplementation.
The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Unilateral Knee Extension Eccentric Exercise
Authors: Legault Zachary , Bagnall Nicholas , Kimmerly Derek S.
Published: March 2015

The study aimed to examine the effects that L-glutamine supplementation has on quadriceps muscle strength and soreness ratings following eccentric exercise. It was hypothesized that glutamine ingestion would quicken the recovery rate of peak force production and decrease muscle soreness ratings over a 72-hr recovery period. Sixteen healthy participants (8♀/8♂; 22 ± 4 years) volunteered in a double-blind, randomized, placebo-controlled crossover study. Supplement conditions consisted of isoenergetic placebo (maltodextrin, 0.6 g·kg-1·day-1) and L-glutamine (0.3 g·kg-1·day-1 + 0.3 g·kg-1·day-1 maltodextrin) ingestion once per day over 72 hr. Knee extensor peak torque at 0°, 30°, and 180° per second and muscle soreness were measured before, immediately following, 24, 48, and 72 hr posteccentric exercise. Eccentric exercise consisted of 8 sets (10 repetitions/set) of unilateral knee extension at 125% maximum concentric force with 2-min rest intervals. L-glutamine resulted in greater relative peak torque at 180°/sec both immediately after (71 ± 8% vs. 66 ± 9%), and 72 hr (91 ± 8% vs. 86 ± 7%) postexercise (all, p < .01). In men, L-glutamine produced greater (p < .01) peak torques at 30°/sec postexercise. Men also produced greater normalized peak torques at 30°/sec (Nm/kg) in the L-glutamine condition than women (all, p < .05). In the entire sample, L-glutamine resulted in lower soreness ratings at 24 (2.8 ± 1.2 vs. 3.4 ± 1.2), 48 (2.6 ± 1.4 vs. 3.9 ± 1.2), and 72 (1.7 ± 1.2 vs. 2.9 ± 1.3) hr postexercise (p < .01). The L-glutamine supplementation resulted in faster recovery of peak torque and diminished muscle soreness following eccentric exercise. The effect of L-glutamine on muscle force recovery may be greater in men than women.
Postexercise Glycogen Recovery and Exercise Performance is Not Significantly Different Between Fast Food and Sport Supplements
Authors: Cramer Michael J. , Dumke Charles L. , Hailes Walter S. , Cuddy John S. , Ruby Brent C.
Published: March 2015

A variety of dietary choices are marketed to enhance glycogen recovery after physical activity. Past research informs recommendations regarding the timing, dose, and nutrient compositions to facilitate glycogen recovery. This study examined the effects of isoenergetic sport supplements (SS) vs. fast food (FF) on glycogen recovery and exercise performance. Eleven males completed two experimental trials in a randomized, counterbalanced order. Each trial included a 90-min glycogen depletion ride followed by a 4-hr recovery period. Absolute amounts of macronutrients (1.54 ± 0.27 g·kg-1 carbohydrate, 0.24 ± 0.04 g·kg fat-1, and 0.18 ± 0.03g·kg protein-1) as either SS or FF were provided at 0 and 2 hr. Muscle biopsies were collected from the vastus lateralis at 0 and 4 hr post exercise. Blood samples were analyzed at 0, 30, 60, 120, 150, 180, and 240 min post exercise for insulin and glucose, with blood lipids analyzed at 0 and 240 min. A 20k time-trial (TT) was completed following the final muscle biopsy. There were no differences in the blood glucose and insulin responses. Similarly, rates of glycogen recovery were not different across the diets (6.9 ± 1.7 and 7.9 ± 2.4 mmol·kg wet weight- 1·hr-1 for SS and FF, respectively). There was also no difference across the diets for TT performance (34.1 ± 1.8 and 34.3 ± 1.7 min for SS and FF, respectively. These data indicate that short-term food options to initiate glycogen resynthesis can include dietary options not typically marketed as sports nutrition products such as fast food menu items.
Hydration Status and Sodium Balance of Endurance Runners Consuming Postexercise Supplements of Varying Nutrient Content
Authors: Pryor J. Luke , Johnson Evan C. , Del Favero Jeffery , Monteleone Andrew , Armstrong Lawrence E. , Rodriguez Nancy R.
Published: March 2015

Postexercise protein and sodium supplementation may aid recovery and rehydration. Preserved beef provides protein and contains high quantities of sodium that may alter performance related variables in runners. The purpose of this study was to determine the effects of consuming a commercial beef product postexercise on sodium and water balance. A secondary objective was to characterize effects of the supplementation protocols on hydration, blood pressure, body mass, and running economy. Eight trained males (age = 22 ± 3 y, V̇O2max = 66.4 ± 4.2 ml·kg-1·min-1) completed three identical weeks of run training (6 run·wk-1, 45 ± 6 min·run-1, 74 ± 5% HRR). After exercise, subjects consumed either, a beef nutritional supplement (beef jerky; [B]), a standard recovery drink (SRD), or SRD+B in a randomized counterbalanced design. Hydration status was assessed via urinary biomarkers and body mass. No main effects of treatment were observed for 24 hr urine volume (SRD, 1.7 ± 0.5; B, 1.8 ± 0.6; SRD+B, 1.4 ± 0.4 L·d-1), urine specific gravity (1.016 ± 0.005, 1.018 ± 0.006, 1.017 ± 0.006) or body mass (68.4 ± 8.2, 68.3 ± 7.7, 68.2 ± 8.1 kg). No main effect of treatment existed for sodium intake—loss (-713 ± 1486; -973 ± 1123; -980 ± 1220 mg·d-1). Mean arterial pressure (81.0 ± 4.6, 81.1 ± 7.3, 83.8 ± 5.4 mm Hg) and average exercise running economy (V̇O2: SRD, 47.9 ± 3.2; B, 47.2 ± 2.6; SRD+B, 46.2 ± 3.4 ml·kg-1·min-1) was not affected. Urinary sodium excretion accounted for the daily sodium intake due to the beef nutritional supplement. Findings suggest the commercial beef snack is a viable recovery supplement following endurance exercise without concern for hydration status, performance decrements, or cardiovascular consequences.
Rapid Weight Loss Elicits Harmful Biochemical and Hormonal Responses in Mixed Martial Arts Athletes
Authors: Coswig Victor Silveira , Fukuda David Hideyoshi , Del Vecchio Fabrício Boscolo
Published: March 2015

The purpose of this study was to compare biochemical and hormonal responses between mixed martial arts (MMA) competitors with minimal prefight weight loss and those undergoing rapid weight loss (RWL). Blood samples were taken from 17 MMA athletes (Mean± SD; age: 27.4 ±5.3yr; body mass: 76.2 ± 12.4kg; height: 1.71 ± 0.05m and training experience: 39.4 ± 25 months) before and after each match, according to the official events rules. The no rapid weight loss (NWL, n = 12) group weighed in on the day of the event (~30 min prior fight) and athletes declared not having used RWL strategies, while the RWL group (n = 5) weighed in 24 hr before the event and the athletes claimed to have lost 7.4 ± 1.1kg, approximately 10% of their body mass in the week preceding the event. Results showed significant (p < .05) increases following fights, regardless of group, in lactate, glucose, lactate dehydrogenase (LDH), creatinine, and cortisol for all athletes. With regard to group differences, NWL had significantly (p < .05) greater creatinine levels (Mean± SD; pre to post) (NWL= 101.6 ± 15–142.3 ± 22.9μmol/L and RWL= 68.9 ± 10.6–79.5 ± 15.9μmol/L), while RWL had higher LDH (median [interquartile range]; pre to post) (NWL= 211.5[183–236] to 231[203–258]U/L and RWL= 390[370.5–443.5] to 488[463.5–540.5]U/L) and AST (NWL= 30[22–37] to 32[22–41]U/L and 39[32.5–76.5] to 72[38.5–112.5] U/L) values (NWL versus RWL, p < .05). Post hoc analysis showed that AST significantly increased in only the RWL group, while creatinine increased in only the NWL group. The practice of rapid weight loss showed a negative impact on energy availability and increased both muscle damage markers and catabolic expression in MMA fighters.
Pink Noise in Rowing Ergometer Performance and the Role of Skill Level
Authors: Den Hartigh Ruud J. R. , Cox Ralf F. A. , Gernigon Christophe , Van Yperen Nico W. , Van Geert Paul L. C.
Published: March 2015

The aim of this study was to examine (1) the temporal structures of variation in rowers’ (natural) ergometer strokes to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled rowers completed 550 strokes on a rowing ergometer. Detrended Fluctuation Analysis was used to quantify the temporal structure of the intervals between force peaks. Results showed that the temporal structure differed from random, and revealed prominent patterns of pink noise for each rower. Furthermore, the high-skilled rowers demonstrated more pink noise than the lower-skilled rowers. The presence of pink noise suggests that rowing performance emerges from the coordination among interacting component processes across multiple time scales. The difference in noise pattern between high-skilled and lower-skilled athletes indicates that the complexity of athletes’ motor organization is a potential key characteristic of elite performance.
Ab initio calculation of the neutron-proton mass difference
Authors: Borsanyi Sz. , Durr S. , Fodor Z. , Hoelbling C. , Katz S. D. , Krieg S. , Lellouch L. , Lippert T. , Portelli A. , Szabo K. K. , Toth B. C.
Published: March 2015

Weighing the neutron against the proton

Elementary science textbooks often state that protons have the same mass as neutrons. This is not far from the truth—the neutron is about 0.14% heavier (and less stable) than the proton. The precise value is important, because if the mass difference were bigger or smaller, the world as we know it would likely not exist. Borsanyi
et al.
calculated the mass difference to high precision using a sophisticated approach that took into account the various forces that exist within a nucleon. The calculations reveal how finely tuned our universe needs to be.

Science
, this issue p.
1452
Intergenerational transmission of child abuse and neglect: Real or detection bias?
Authors: Widom Cathy Spatz , Czaja Sally J. , DuMont Kimberly A.
Published: March 2015

Abuse from generation to generation?

Parents who were abused as children are thought more likely to abuse their own children. Widom
et al.
compared reports from parents, from children, and from child protective service agency records gathered on the same families and on matched controls. They observed different findings depending on which information they used. Increases in sexual abuse and neglect relative to controls were reported by children of abuse victims. However, much of the believed transmission of abuse and neglect between generations could be ascribed to surveillance or detection bias targeted at parents with childhood histories of abuse or neglect.

Science
, this issue p.
1480