bluuebunny/crossref_metadata_2025 huggingface dataset:
A systematic review of transanal total mesorectal excision: is this the future of rectal cancer surgery?
Authors: Simillis C. , Hompes R. , Penna M. , Rasheed S. , Tekkis P. P.
Published: October 2015

Aim

The surgical technique used for transanal total mesorectal excision (TaTME) was reviewed including the oncological quality of resection and the peri‐operative outcome.

Method

A literature search of MEDLINE, Embase, Science Citation Index Expanded and Cochrane was performed in order to identify studies reporting on TaTME.

Results

Thirty‐six studies (eight case reports, 24 case series and four comparative studies) were identified, reporting 510 patients who underwent TaTME. The mean age ranged from 43 to 80 years and the mean body mass index from 21.7 to 31.8 kg/m2. The mean distance of the tumour from the anal verge ranged from 4 to 9.7 cm. The mean operation time ranged from 143 to 450 min and mean operative blood loss from 22 to 225 ml. The ratio of hand‐sewn coloanal to stapled anastomoses performed was 2:1. One death was reported and the peri‐operative morbidity rate was 35%. The anastomotic leakage rate was 6.1% and the reoperation rate was 3.7%. The mean hospital stay ranged from 4.3 to 16.6 days. The mesorectal excision was described as complete in 88% cases, nearly complete in 6% and incomplete in 6%. The circumferential resection margin was negative in 95% of cases and the distal resection margin was negative in 99.7%.

Conclusion

TaTME is a feasible and reproducible technique, with good quality of oncological resection. Standardization of the technique is required with formal training. Clear indications for this procedure need to be defined and its safety further assessed in future trials.
Effects of heterodimeric bone morphogenetic protein‐2/7 on osteogenesis of human adipose‐derived stem cells
Authors: Zhang Xiao , Guo Jing , Wu Gang , Zhou Yongsheng
Published: October 2015

Objective

Roles of bone morphogenetic proteins (BMPs) on osteogenesis of human adipose‐derived stem cells (hASCs) remain ambiguous. In this study, we evaluated in vitro and in vivo functional characteristics of BMPs of different dimerization types, with the aim of determining osteoinductive efficiency of heterodimeric BMP‐2/7 on osteogenesis of hASCs.

Materials and methods

We explored osteoinductive effects of three different BMPs by using cell DNA assay, alkaline phosphatase (ALP) activity assay, alizarin red staining and mineralization assay, and real‐time PCR, in vitro. Also, we examined ectopic bone formation in nude mice by using soft X‐ray, histomorphometric and immunohistochemical analyses in vivo.

Results

In our dose–response study, we showed that BMPs with both dimerization types did not induce in vitro osteogenesis of hASCs without osteogenic medium (OM). In the presence of OM, BMPs significantly enhanced hASC osteogenesis in a dose‐dependent manner. In in vivo experiments, our analyses indicated that BMPs promoted osteogenesis of hASCs without in vitro osteogenic induction. However, both in vitro and in vivo, there were no significant differences in hASC osteogenic induction between heterodimeric and homodimeric BMPs.

Conclusions

Heterodimeric BMP‐2/7 significantly promoted osteogenesis of hASCs in vitro and in vivo. However, BMP‐2/7 was not found to be a stronger inducer of osteogenesis compared to homodimeric either BMP‐2 or BMP‐7.
HGF and IGF‐1 promote protective effects of allogeneic BMSC transplantation in rabbit model of acute myocardial infarction
Authors: Zhang Guang‐Wei , Gu Tian‐Xiang , Guan Xiao‐Yu , Sun Xue‐Jun , Qi Xun , Li Xue‐Yuan , Wang Xiao‐Bing , Lv Feng , Yu Lei , Jiang Da‐Qing , Tang Rui
Published: October 2015

Objectives

To explore effects of hepatocyte growth factor (HGF) combined with insulin‐like growth factor 1 (IGF‐1) on transplanted bone marrow mesenchymal stem cells (BMSCs), for treatment of acute myocardial ischaemia.

Materials and methods

After ligation of the left anterior descending artery, rabbits were divided into a Control group, a Factors group (HGF+IGF‐1), a BMSC group and a Factors+BMSCs group. Allogenous BMSCs (1 × 107) and/or control‐released microspheres of 2 μg HGF+2 μg IGF‐1 were intramyocardially injected into infarcted regions. Apoptosis and differentiation of implanted BMSCs, histological and morphological results, and cardiac remodelling and function were evaluated at different time points. In vitro, BMSCs were exposed to HGF, IGF‐1 and both (50 ng/ml) and subsequently proliferation, migration, myocardial differentiation and apoptosis induced by hypoxia, were analysed.

Results

Four weeks post‐operatively, the above indices were significantly improved in Factors+BMSCs group compared to the others (P < 0.01), although Factors and BMSCs group also showed better results than Control group (P < 0.05). In vitro, HGF promoted BMSC migration and differentiation into cardiomyocytes, but inhibited proliferation (P < 0.05), while IGF‐1 increased proliferation and migration, and inhibited apoptosis induced by hypoxia (P < 0.05), but did not induce myocardial differentiation. Combination of HGF and IGF‐1 significantly promoted BMSCs capacity for migration, differentiation and lack of apoptosis (P < 0.05).

Conclusions

Combination of HGF and IGF‐1 activated BMSCs complementarily, and controlled release of the two factors promoted protective potential of transplanted BMSCs to repair infarcted myocardium. This suggests a new strategy for cell therapies to overcome acute ischemic myocardial injury.
Network‐selectivity and stimulus‐discrimination in the primary visual cortex: cell‐assembly dynamics
Authors: Bharmauria Vishal , Bachatene Lyes , Cattan Sarah , Brodeur Simon , Chanauria Nayan , Rouat Jean , Molotchnikoff Stéphane
Published: October 2015

Visual neurons coordinate their responses in relation to the stimulus; however, the complex interplay between a stimulus and the functional dynamics of an assembly still eludes neuroscientists. To this aim, we recorded cell assemblies from multi‐electrodes in the primary visual cortex of anaesthetized cats in response to randomly presented sine‐wave drifting gratings whose orientation tilted in 22.5° steps. Cross‐correlograms revealed the functional connections at all the tested orientations. We show that a cell‐assembly discriminates between orientations by recruiting a ‘salient’ functional network at every presented orientation, wherein the connections and their strengths (peak‐probabilities in the cross‐correlogram) change from one orientation to another. Within these assemblies, closely tuned neurons exhibited increased connectivity and connection‐strengths compared with differently tuned neurons. Minimal connectivity between untuned neurons suggests the significance of neuronal selectivity in assemblies. This study reflects upon the dynamics of functional connectivity, and brings to the fore the importance of a ‘signature’ functional network in an assembly that is strictly related to a specific stimulus. It appears that an assembly is the major ‘functional unit’ of information processing in cortical circuits, rather than the individual neurons.
A structural snapshot of the rhodopsin–arrestin complex
Authors: Kang Yanyong , Gao Xiang , Zhou X. Edward , He Yuanzheng , Melcher Karsten , Xu H. Eric
Published: October 2015

The crystal structure of the rhodopsin–arrestin complex provides important insights into how G protein‐coupled receptor signaling is terminated by arrestin and a structural basis for understanding the mechanism of arrestin‐based signaling.
Where Does Water Go During Hydraulic Fracturing?
Authors: O'Malley D. , Karra S. , Currier R. P. , Makedonska N. , Hyman J. D. , Viswanathan H. S.
Published: October 2015

During hydraulic fracturing millions of gallons of water are typically injected at high pressure into deep shale formations. This water can be housed in fractures, within the shale matrix, and can potentially migrate beyond the shale formation via fractures and/or faults raising environmental concerns. We describe a generic framework for producing estimates of the volume available in fractures and undamaged shale matrix where water injected into a representative shale site could reside during hydraulic fracturing, and apply it to a representative site that incorporates available field data. The amount of water that can be stored in the fractures is estimated by calculating the volume of all the fractures associated with a discrete fracture network (DFN) based on real data and using probability theory to estimate the volume of smaller fractures that are below the lower cutoff for the fracture radius in the DFN. The amount of water stored in the matrix is estimated utilizing two distinct methods—one using a two‐phase model at the pore‐scale and the other using a single‐phase model at the continuum scale. Based on these calculations, it appears that most of the water resides in the matrix with a lesser amount in the fractures.
Electrical and Mechanical Properties of 5YSZ Tubular Thin Film Prepared by Screen Printing Method
Authors: Ghatee Mojtaba , Salari Farid
Published: October 2015

In this study, 5 mol% yttria‐stabilized zirconia tubular thin film is fabricated by screen printing method. The processing parameters are investigated. The microstructure of the samples is analyzed by X‐ray diffraction and scanning electron microscope. The electrical conductivity of the samples is studied by impedance spectroscopy. The microhardness, nanohardness, and Young's modulus of the thin films are measured. It is found that the proper weight ratio of zirconia powder to organic constituents of the ink is 3:2. The hardness of tubular thin film is higher than that of the planar specimen. The conductivity of 5YSZ tubular thin film at 850°C is 0.028 S/cm.
The Nanocrystalline SnO2–TiO2 System‒Part II: Surface Energies and Thermodynamic Stability
Authors: Miagava Joice , da Silva Andre L. , Navrotsky Alexandra , Castro Ricardo H.R. , Gouvêa Douglas
Published: October 2015

The thermodynamic stability of nanocrystalline SnO2–TiO2 solid solutions was studied experimentally. Microcalorimetry of water adsorption revealed a systematic decrease in the surface energy with increasing Ti4+ content in the SnO2‐rich compositions, consistent with previous reports of Ti4+ segregation on the surface. The surface energy change was accompanied by an increase in the magnitude of the heat of water adsorption, also indicating a modification of the SnO2 surface by Ti4+. Supporting the water adsorption data, calculations using high‐temperature oxide melt solution calorimetry data also suggest a decrease in the interface energies. A thermodynamic analysis showed that the observed surface energy decrease is responsible for an increase in the stability of solid solutions in the nanophase regime. Although a miscibility gap is expected in this system from bulk phase diagrams, the surface energy contribution modifies the bulk trend and promotes extensive solid solutions when the surface area is above a critical value dependent on the surface energy and the bulk enthalpy of mixing.
Sufficiency Grounded as Sufficiently Free: A Reply to Shlomi Segall
Authors: Nielsen Lasse
Published: October 2015

Telic sufficientarianism is the view that it is better, other things equal, if people are lifted above some sufficiency threshold of special moral importance. In a recent contribution, Shlomi Segall has raised the following objection to this position: The telic ideal of sufficiency can neither be grounded on (i) any personal value, nor (ii) any impersonal value. Consequently, sufficientarianism is groundless. This article contains a rejoinder to this critique. Its main claim is that the value of autonomy holds strong potential for grounding sufficiency. It argues, firstly, that autonomy carries both personal value for its recipient as well as impersonal value, and that both of these values are suitable for grounding sufficiency. It thus follows that we should reject both (i) and (ii). Secondly, although autonomy is presumably the strongest candidate for grounding sufficiency, the article provides some counterargument to Segall's rejection of the other candidates — the impersonal value of virtue; the personal value for the allocator; and the personal value for others. If the arguments are sound, they show that we need not worry about sufficientarianism being groundless.
The quality ofEuropean dermatological guidelines: critical appraisal of the quality ofEDFguidelines using theAGREE IIinstrument
Authors: Werner R.N. , Marinović B. , Rosumeck S. , Strohal R. , Haering N.S. , Weberschock T. , Dreher A.C. , Nast A.
Published: October 2015

Clinical practice guidelines are systematically developed tools to assist clinicians and health policy makers in decision making for clearly defined clinical situations. In the light of the demand for evidence‐based medicine and quality in health care and the increasing methodological requirements concerning guidelines development, it is important to evaluate existing practice guidelines to systematically identify strengths and weaknesses. Currently, the most accepted tool for the methodological evaluation of guidelines is theAppraisal ofGuidelines forResearch &Evaluation (AGREE)Instrument. Intention of this assessment is to identify and critically appraise clinical practice guidelines commissioned by theEuropeanDermatologyForum (EDF). A quality assessment of a predefined set of guidelines, including all available clinical practice guidelines published on theEDFguidelines internet site, was performed using theAGREE IIinstrument. To assure an objective assessment, four independent assessments were performed by evaluators situated in differentEuropean countries. Twenty‐fiveEDFguidelines covering different dermatological topics were identified and evaluated. The assessment included seven guidelines developed on the highest methodological standard (systematic literature search and structured consensus conference,S3). Eighteen guidelines were identified that were based on either a structured consensus process (S2k), a systematic literature assessment (S2e) or on informal consensus only (S1). The methodological and reporting quality among the evaluated guidelines was heterogeneous.S3 guidelines generally received the highest scores. The domains ‘clarity of presentation’ and ‘scope and purpose’ achieved the highest mean ratings within the different domains of assessment, whereas the domains of ‘applicability’, ‘stakeholder involvement’ and ‘editorial independence’ scored poorly. Considering the large variations in the achieved scores, there is need for methodological harmonization within theEDFguidelines to achieve comparable methodological standards.
Donors’ Policy Consistency and Economic Growth
Authors: Gary Aurore , Maurel Mathilde
Published: October 2015

Bilateral donors have recognized the need to improve the consistency of donors' policies towards developing countries. However, the impact of policy consistency on economic development has not been documented in the literature to date. Our contribution is twofold: firstly, we use the indices provided by the Center for Global Development (CGD) to construct indicators of overall donors' policies performance and donors' policies consistency at the recipient level. Secondly, we assume that the growth‐consistency nexus is dynamic and our results suggest that an increase in consistency by one standard deviation increases growth on average by 1,1 percentage point. This result holds for different instrumentation strategies and robustness checks. We also highlight that the overall policy performance (OPP) increases growth above a sufficient level of donors' policies diversification and level of OPP.
Convergence: A Story of Quantiles and Spillovers
Authors: Kostov Philip , Le Gallo Julie
Published: October 2015

In this paper, we revisit the analysis of cross‐country convergence by combining spatial econometrics and panel quantile regressions to estimate conditional β‐convergence models. Moreover, we use both exogenous and endogenous weight matrices. Our results show that indeed the effects of initial per capita income, investment rate, population growth and human capital on growth rates vary considerably across the estimated quantiles. Convergence is not a generalized phenomenon across the conditional growth distribution. Moreover, while using exogenous spatial weight matrices does not substantially alter the findings found in a‐spatial models, it appears that endogenous weights dramatically affect the estimates of the convergence process.
Regulation of filamentation in the human fungal pathogen Candida tropicalis
Authors: Zhang Qiuyu , Tao Li , Guan Guobo , Yue Huizhen , Liang Weihong , Cao Chengjun , Dai Yu , Huang Guanghua
Published: October 2015

The yeast–filament transition is essential for the virulence of a variety of fungi that are pathogenic to humans. N‐acetylglucosamine (GlcNAc) is a potent inducer of filamentation in Candida albicans and thermally dimorphic fungi such as Histoplasma capsulatum and Blastomyces dermatitidis. However, GlcNAc suppresses rather than promotes filamentation in Candida tropicalis, a fungal species that is closely related to C. albicans. Despite the intensive study in C. albicans, the regulatory mechanism of filamentation is poorly understood. In this study, we demonstrate that the cAMP signaling pathway plays a central role in the regulation of filamentation in C. tropicalis. By screening an overexpression library of 156 transcription factors, we have identified approximately 40 regulators of filamentous growth. Although most of the regulators (e.g., Tec1, Gat2, Nrg1, Sfl1, Sfl2 and Ash1) demonstrate a conserved role in the regulation of filamentation, similar to their homologues in C. albicans or Saccharomyces cerevisiae, a number of transcription factors (e.g., Wor1, Bcr1, Stp4, Efh1, Csr1 and Zcf17) play a specific role in C. tropicalis. Our findings indicate that multiple interconnected signaling pathways are involved in the regulation of filamentation in C. tropicalis. These mechanisms have conserved and divergent features among different Candida species.
Probiotic supplementation for preventing invasive fungal infections in preterm neonates – a systematic review and meta‐analysis
Authors: Agrawal Sachin , Rao Shripada , Patole Sanjay
Published: October 2015

Invasive fungal infections (IFI) are associated with significant health burden in preterm neonates. The objective of this study was to systematically review effect of probiotic supplementation (PS) for preventing IFI in preterm neonates. We searched Cochrane Central Register of Controlled Trials, Medline, Embase, Cumulative Index of Nursing and Allied Health Literature, and proceedings of the Pediatric Academic Society meetings in August 2014. Study selection was performed on randomised controlled trials (RCT) of PS in neonates born <37 weeks. Primary outcome of this study was IFI (Isolation of fungus in blood/body fluids) and secondary outcome was fungal gut colonisation. Information on IFI/colonisation was available in 8 of 27 RCT. Meta‐analysis (fixed effects model) showed that PS reduced the risk of IFI (RR: 0.50, 95% CI: 0.34, 0.73, I2 = 39%). Results were not significant with random effects model (RR: 0.64, 95%, CI: 0.30, 1.38, P = 0.25, I2 = 39%). Analysis after excluding the study with a high baseline incidence (75%) of IFI showed that PS had no significant benefits (RR: 0.89; 95% CI: 0.44, 1.78). Of the five studies reporting on fungal gut colonisation, three reported benefits of probiotics; two did not. Current evidence is limited to derive firm conclusions on the effect of PS for preventing IFI/gut colonisation in preterm neonates.
Excessive coupling of the salience network with intrinsic neurocognitive brain networks during rectal distension in adolescents with irritable bowel syndrome: a preliminary report
Authors: Liu X. , Silverman A. , Kern M. , Ward B. D. , Li S.‐J. , Shaker R. , Sood M. R.
Published: October 2015

Background

The neural network mechanisms underlying visceral hypersensitivity in irritable bowel syndrome (IBS) are incompletely understood. It has been proposed that an intrinsic salience network plays an important role in chronic pain andIBSsymptoms. Using neuroimaging, we examined brain responses to rectal distension in adolescentIBSpatients, focusing on determining the alteration of salience network integrity inIBSand its functional implications in current theoretical frameworks. We hypothesized that (i) brain responses to visceral stimulation in adolescents are similar to those in adults, and (ii)IBSis associated with an altered salience network interaction with other neurocognitive networks, particularly the default mode network (DMN) and executive control network (ECN), as predicted by the theoretical models.

Methods

Irritable bowel syndrome patients and controls received subliminal and liminal rectal distension during imaging. Stimulus‐induced brain activations were determined. Salience network integrity was evaluated by the functional connectivity of its seed regions activated by rectal distension in the insular and cingulate cortices.

Key Results

Compared with controls,IBSpatients demonstrated greater activation to rectal distension in neural structures of the homeostatic afferent and emotional arousal networks, especially the anterior cingulate and insular cortices. Greater brain responses to liminalvssubliminal distension were observed in both groups. Particularly,IBSis uniquely associated with an excessive coupling of the salience network with theDMNandECNin their key frontal and parietal node areas.

Conclusions & Inferences

Our study provided consistent evidence supporting the theoretical predictions of altered salience network functioning as a neuropathological mechanism ofIBSsymptoms.
Evolution of marginal populations of an invasive vine increases the likelihood of future spread
Authors: Kilkenny Francis F. , Galloway Laura F.
Published: October 2015

The prediction of invasion patterns may require an understanding of intraspecific differentiation in invasive species and its interaction with climate change. We compare Japanese honeysuckle (Lonicera japonica) plants from the core (100–150 yr old) and northern margin (< 65 yr old) of their North American invaded range to determine whether evolution during invasion increases the probability of future expansion.

Plants from populations in the core and margin were compared in two sites beyond the northern range edge to assess their potential to invade novel areas. Data were compared with previous work to assess the effect of latitudinal climate on L. japonica spread. Winter survival in current climates was modeled and projected for future climates to predict future spread.

Margin plants were larger and had 60% greater survival than core plants at sites beyond the northern range edge. Overall, winter survival decreased with increasing latitude and decreasing temperature, and was greater in margin plants than core plants.

Models suggested that greater winter tolerance in margin populations has increased L. japonica's northward spread by 76 km, and that this survival advantage will persist under future climates. These results demonstrate that evolution during invasion may increase spread beyond predictions using increasing global temperatures alone.
Moving from conceptual ambiguity to knowledgeable action: using a critical realist approach to studying moral distress
Authors: Musto Lynn C. , Rodney Patricia A.
Published: October 2015

Moral distress is a phenomenon that has been receiving increasing attention in nursing and other health care disciplines. Moral distress is a concept that entered the nursing literature – and subsequently the health care ethics lexicon – in 1984 as a result of the work done by American philosopher and bioethicist Andrew Jameton. Over the past decade, research into moral distress has extended beyond the profession of nursing as other health care disciplines have come to question the impact of moral constraint on individual practitioners, professional practice, and patient outcomes. Along with increased interest in the phenomenon of moral distress have come increasing critiques – critiques that in their essence point to a serious lack of conceptual clarity in the definition, study, and application of the concept. Foundational to gaining conceptual clarity in moral distress in order to develop strategies to prevent and ameliorate the experience is a careful revisiting of the epistemological assumptions underpinning our knowledge and use of the concept of moral distress. It is our contention that the conceptual challenges reveal flaws in the original understanding of moral distress that are based on an epistemological stance that holds a linear conception of cause and effect coupled with a simplistic perspective of ‘constraint’ and ‘agency’. We need a more nuanced approach to our study of moral distress such that our ontological and epistemological stances help us to better appreciate the complexity of moral agents acting in organizational contexts. We believe that critical realism offers such a nuanced approach.
A palaeoscolecid worm from the Burgess Shale
Authors: Smith Martin R.
Published: October 2015

Palaeoscolecid worms are a ubiquitous group of Early Palaeozoic ecdysozoans that are curiously lacking in the archetypal Cambrian Lagerstätten, the Burgess Shale. Here I describeScathascolex minorgen. et sp. nov, the first unequivocal palaeoscolecid from this site.Scathascolexis armoured with simpleHadimopanella‐like plates, but lacks smaller platelets, pointing to a close affinity with the Palaeoscolecidasensu stricto. Neither preservational nor environmental factors account for the scarcity of palaeoscolecids in the Burgess Shale, which presumably represents an ecological phenomenon.
The Effect of Private Police on Crime: Evidence from a Geographic Regression Discontinuity Design
Authors: MacDonald John M. , Klick Jonathan , Grunwald Ben
Published: October 2015

Research demonstrates that police reduce crime. We study this question by using a natural experiment in which a private university increased the number of police patrols within an arbitrarily defined geographic boundary. Capitalizing on the discontinuity in patrols at the boundary, we estimate that the extra police decreased crime in adjacent city blocks by 43–73%. Our results are consistent with findings from prior work that used other kinds of natural experiment. The paper demonstrates the utility of the geographic regression discontinuity design for estimating the effects of extra public or private services on a variety of outcomes.
Gibberellic acid signaling is required for ambient temperature‐mediated induction of flowering in Arabidopsis thaliana
Authors: Galvão Vinicius Costa , Collani Silvio , Horrer Daniel , Schmid Markus
Published: October 2015

Distinct molecular mechanisms integrate changes in ambient temperature into the genetic pathways that govern flowering time in Arabidopsis thaliana. Temperature‐dependent eviction of the histone variant H2A.Z from nucleosomes has been suggested to facilitate the expression of FT by PIF4 at elevated ambient temperatures. Here we show that, in addition to PIF4, PIF3 and PIF5, but not PIF1 and PIF6, can promote flowering when expressed specifically in phloem companion cells (PCC), where they can induce FT and its close paralog, TSF. However, despite their strong potential to promote flowering, genetic analyses suggest that the PIF genes seem to have only a minor role in adjusting flowering in response to photoperiod or high ambient temperature. In addition, loss of PIF function only partially suppressed the early flowering phenotype and FT expression of the arp6 mutant, which is defective in H2A.Z deposition. In contrast, the chemical inhibition of gibberellic acid (GA) biosynthesis resulted in a strong attenuation of early flowering and FT expression in arp6. Furthermore, GA was able to induce flowering at low temperature (15°C) independently of FT, TSF, and the PIF genes, probably directly at the shoot apical meristem. Together, our results suggest that the timing of the floral transition in response to ambient temperature is more complex than previously thought and that GA signaling might play a crucial role in this process.
EFFECTS OF INTRAVENOUS DEXMEDETOMIDINE ON CARDIAC CHARACTERISTICS MEASURED USING RADIOGRAPHY AND ECHOCARDIOGRAPHY IN SIX HEALTHY DOGS
Authors: Wang Hsien‐Chi , Hung Cih‐Ting , Lee Wei‐Ming , Chang Kui‐Ming , Chen Kuan‐Sheng
Published: October 2015

Dexmedetomidine is a highly specific and selective α2‐adrenergic receptor agonist widely used in dogs for sedation or analgesia. We hypothesized that dexmedetomidine may cause significant changes in radiographic and echocardiographic measurements. The objective of this prospective cross‐sectional study was to test this hypothesis in a sample of six healthy dogs. Staff‐owned dogs were recruited and received a single dose of dexmedetomidine 250 μg/m2intravenously. Thoracic radiography and echocardiography were performed 1 h before treatment, and repeated 10 and 30 min after treatment, respectively. One observer recorded cardiac measurements from radiographs and another observer recorded echocardiographic measurements. Vertebral heart score and cardiac size to thorax ratio on the ventrodorsal projection increased from 9.8 ± 0.6 v to 10.3 ± 0.7 v (P= 0.0007) and 0.61 ± 0.04 to 0.68 ± 0.03 (P= 0.0109), respectively. E point‐to‐septal separation and left ventricle internal diameter in diastole and systole increased from 2.4 ± 1.1 to 6.6 ± 1.9 mm, 32.3 ± 8.1 to 35.5 ± 8.8 mm, and 19.4 ± 6 to 27.0 ± 7.2 mm, respectively (P< 0.05). Fractional shortening and sphericity index decreased from 40.7 ± 5.8 to 24.4 ± 2.9%, and 1.81 ± 0.07 to 1.58 ± 0.04, respectively (P< 0.05). Moderate‐to‐severe mitral regurgitation and mild pulmonic regurgitation occurred in all dogs after dexmedetomidine administration. Findings indicated that dexmedetomidine could cause false‐positive diagnoses of valvular regurgitation and cardiomegaly in dogs undergoing thoracic radiography and echocardiography.
Characteristics of renal sympathetic nerve single units in rabbits with angiotensin‐induced hypertension
Authors: Burke Sandra L. , Lukoshkova Elena V. , Head Geoffrey A.
Published: October 2015

New Findings

What is the central question of this study?

Is the elevated whole renal nerve activity observed with chronic low‐dose angiotensin the result of recruitment or changes in firing frequency of renal neurons?

What is the main finding and its importance?

Resting firing frequency of renal neurons is lower with low‐dose angiotensin, but cardiac rhythmicity is reduced by high‐dose angiotensin. Unitary responses to baroreceptor stimulation are reduced, but there is greater sensitivity of central chemoreceptor pathways. Elevated nerve activity in conscious animals is the result of recruitment of individual neurons normally silent but available for recruitment during physiological challenge.

We examined the effect of chronic angiotensin (Ang II)‐induced hypertension on activity of postganglionic renal sympathetic units to determine whether altered whole renal nerve activity is due to recruitment or changes in firing frequency. Rabbits were treated with a low (20 ng kg−1 min−1, 8 weeks) or high dose (50 ng kg−1 min−1, 4 weeks) of Ang II before the experiment under chloralose–urethane anaesthesia. Spontaneously active units were detected from multiunit recordings using an algorithm that separated units by action potential shape using templates that matched spikes within a prescribed standard deviation. Multiunit sympathetic nerve activity was 40% higher in rabbits treated with low‐dose Ang II than in sham (P = 0.012) but not different in high‐dose Ang II. Resting firing frequency was similar in sham rabbits (1.00 ± 0.09 spikes s−1, n = 144) and in those treated with high‐dose Ang II (1.10 ± 0.08 spikes s−1, n = 112) but was lower with low‐dose Ang II (0.65 ± 0.08 spikes s−1, n = 149, P < 0.05). Unit firing rhythmicity was linked to the cardiac cycle and was similar in sham and low‐dose Ang II groups but 29–32% lower in rabbits treated with high‐dose Ang II (P < 0.001). Cardiac linkage followed a similar pattern during hypoxia. All units showed baroreceptor dependency. Baroreflex gain and range were reduced and curves shifted to the right in Ang II groups. Firing frequency during hypoxia increased by +39% in low‐dose Ang II and +82% in shams, but the greatest increase was in the high‐dose Ang II group (+103%, Pdose = 0.001). Responses to hypercapnia were similar in all groups. Increases in sympathetic outflow in hypertension caused by low‐dose chronic Ang II administration are due to recruitment of neurons, but high‐dose Ang II increases firing frequency in response to chemoreceptor stimuli independently of the arterial baroreceptors.
Bioderived Fuel Blend Dilution of Marine Engine Oil and Impact on Friction and Wear Behavior
Authors: Ajayi Oyelayo O. , Lorenzo-Martin Cinta , Fenske George , Corlett John , Murphy Chris , Przesmitzki Steve
Published: October 2015

To reduce the amount of petroleum-derived fuel used in vehicles and vessels powered by internal combustion engines (ICEs), the addition of bioderived fuel extenders is a common practice. Ethanol is perhaps the most common bioderived fuel used for blending, and butanol is being evaluated as a promising alternative. The present study determined the fuel dilution rate of three lubricating oils (pure gasoline (E0), gasoline–10% ethanol blend (E10), and gasoline–16% isobutanol blend (i-B16)) in a marine engine operating in on-water conditions with a start-and-stop cycle protocol. The level of fuel dilution increased with the number of cycles for all three fuels. The most dilution was observed with i-B16 fuel, and the least with E10 fuel. In all cases, fuel dilution substantially reduced the oil viscosity. The impacts of fuel dilution and the consequent viscosity reduction on the lubricating capability of the engine oil in terms of friction, wear, and scuffing prevention were evaluated by four different tests protocols. Although the fuel dilution of the engine oil had minimal effect on friction, because the test conditions were under the boundary lubrication regime, significant effects were observed on wear in many cases. Fuel dilution was also observed to reduce the load-carrying capacity of the engine oils in terms of scuffing load reduction.
Computational Fluid Dynamics Analysis of a Machine Hammer Peened Surface Structure for Lubricated Sliding Contacts
Authors: Trauth D. , Klocke F. , Terhorst M. , Mattfeld P.
Published: October 2015

Machine hammer peening (MHP) is an incremental surface finishing process. It enables both surface smoothing and texturing. Compared to well-established surface texturing processes, MHP has the advantage of simultaneous induction of strain hardening and compressive residual stresses. Both texturing and surface layer modification are very beneficial in case of mixed-boundary lubrication. MHP has been only recently developed. Therefore, the influence of surface textures manufactured by MHP on tribological interactions is unknown and lacks fundamental investigations. In this work, hydrodynamics of MHP textures is investigated by means of a three-dimensional (3D) computational fluid dynamics (CFD) analysis. The analyzed MHP textures have already been experimentally used to reduce friction in strip drawing tests. Using CFD analysis, an optimal arrangement of multiple elliptically shaped surface structures for maximizing the fluid pressure and the load-bearing capacity is determined. Furthermore, a correlation between the determined process parameters and the lubrication properties is presented. Because of significantly high hydrostatic pressures, cavitation is neglected in this work. Additionally, the effect of structure pileups is neglected in this study. Within the range of parameters investigated, it was found that an arrangement of surface textures by MHP should be transversally overlapping and clearly separated longitudinally. High structure depths, lubricant viscosities, and sliding velocities further improve the load-bearing capacity as well as small fluid-film thicknesses.
Simultaneous 3D–2D image registration and C‐arm calibration: Application to endovascular image‐guided interventions
Authors: Mitrović Uroš , Pernuš Franjo , Likar Boštjan , Špiclin Žiga
Published: October 2015

Purpose:

Three‐dimensional to two‐dimensional (3D–2D) image registration is a key to fusion and simultaneous visualization of valuable information contained in 3D pre‐interventional and 2D intra‐interventional images with the final goal of image guidance of a procedure. In this paper, the authors focus on 3D–2D image registration within the context of intracranial endovascular image‐guided interventions (EIGIs), where the 3D and 2D images are generally acquired with the same C‐arm system. The accuracy and robustness of any 3D–2D registration method, to be used in a clinical setting, is influenced by (1) the method itself, (2) uncertainty of initial pose of the 3D image from which registration starts, (3) uncertainty of C‐arm's geometry and pose, and (4) the number of 2D intra‐interventional images used for registration, which is generally one and at most two. The study of these influences requires rigorous and objective validation of any 3D–2D registration method against a highly accurate reference or “gold standard” registration, performed on clinical image datasets acquired in the context of the intervention.

Methods:

The registration process is split into two sequential, i.e., initial and final, registration stages. The initial stage is either machine‐based or template matching. The latter aims to reduce possibly large in‐plane translation errors by matching a projection of the 3D vessel model and 2D image. In the final registration stage, four state‐of‐the‐art intrinsic image‐based 3D–2D registration methods, which involve simultaneous refinement of rigid‐body and C‐arm parameters, are evaluated. For objective validation, the authors acquired an image database of 15 patients undergoing cerebral EIGI, for which accurate gold standard registrations were established by fiducial marker coregistration.

Results:

Based on target registration error, the obtained success rates of 3D to a single 2D image registration after initial machine‐based and template matching and final registration involving C‐arm calibration were 36%, 73%, and 93%, respectively, while registration accuracy of 0.59 mm was the best after final registration. By compensating in‐plane translation errors by initial template matching, the success rates achieved after the final stage improved consistently for all methods, especially if C‐arm calibration was performed simultaneously with the 3D–2D image registration.

Conclusions:

Because the tested methods perform simultaneous C‐arm calibration and 3D–2D registration based solely on anatomical information, they have a high potential for automation and thus for an immediate integration into current interventional workflow. One of the authors’ main contributions is also comprehensive and representative validation performed under realistic conditions as encountered during cerebral EIGI.
Collision prediction software for radiotherapy treatments
Authors: Padilla Laura , Pearson Erik A. , Pelizzari Charles A.
Published: October 2015

Purpose:

This work presents a method of collision predictions for external beam radiotherapy using surface imaging. The present methodology focuses on collision prediction during treatment simulation to evaluate the clearance of a patient's treatment position and allow for its modification if necessary.

Methods:

A Kinect camera (Microsoft, Redmond, WA) is used to scan the patient and immobilization devices in the treatment position at the simulator. The surface is reconstructed using the skanect software (Occipital, Inc., San Francisco, CA). The treatment isocenter is marked using simulated orthogonal lasers projected on the surface scan. The point cloud of this surface is then shifted to isocenter and converted from Cartesian to cylindrical coordinates. A slab models the treatment couch. A cylinder with a radius equal to the normal distance from isocenter to the collimator plate, and a height defined by the collimator diameter is used to estimate collisions. Points within the cylinder clear through a full gantry rotation with the treatment couch at 0°, while points outside of it collide. The angles of collision are reported. This methodology was experimentally verified using a mannequin positioned in an alpha cradle with both arms up. A planning CT scan of the mannequin was performed, two isocenters were marked in pinnacle, and this information was exported to AlignRT (VisionRT, London, UK)—a surface imaging system for patient positioning. This was used to ensure accurate positioning of the mannequin in the treatment room, when available. Collision calculations were performed for the two treatment isocenters and the results compared to the collisions detected the room. The accuracy of the Kinect‐Skanect surface was evaluated by comparing it to the external surface of the planning CT scan.

Results:

Experimental verification results showed that the predicted angles of collision matched those recorded in the room within 0.5°, in most cases (largest deviation −1.2°). The accuracy study for the Kinect‐Skanect surface showed an average discrepancy between the CT external contour and the surface scan of 2.2 mm.

Conclusions:

This methodology provides fast and reliable collision predictions using surface imaging. The use of the Kinect‐Skanect system allows for a comprehensive modeling of the patient topography including all the relevant anatomy and immobilization devices that may lead to collisions. The use of this tool at the treatment simulation stage may allow therapists to evaluate the clearance of a patient's treatment position and optimize it before the planning CT scan is performed. This can allow for safer treatments for the patients due to better collision predictions and improved clinical workflow by minimizing replanning and resimulations due to unforeseen clearance issues.
The development and verification of a highly accurate collision prediction model for automated noncoplanar plan delivery
Authors: Yu Victoria Y. , Tran Angelia , Nguyen Dan , Cao Minsong , Ruan Dan , Low Daniel A. , Sheng Ke
Published: October 2015

Purpose:

Significant dosimetric benefits had been previously demonstrated in highly noncoplanar treatment plans. In this study, the authors developed and verified an individualized collision model for the purpose of delivering highly noncoplanar radiotherapy and tested the feasibility of total delivery automation with Varian TrueBeam developer mode.

Methods:

A hand‐held 3D scanner was used to capture the surfaces of an anthropomorphic phantom and a human subject, which were positioned with a computer‐aided design model of a TrueBeam machine to create a detailed virtual geometrical collision model. The collision model included gantry, collimator, and couch motion degrees of freedom. The accuracy of the 3D scanner was validated by scanning a rigid cubical phantom with known dimensions. The collision model was then validated by generating 300 linear accelerator orientations corresponding to 300 gantry‐to‐couch and gantry‐to‐phantom distances, and comparing the corresponding distance measurements to their corresponding models. The linear accelerator orientations reflected uniformly sampled noncoplanar beam angles to the head, lung, and prostate. The distance discrepancies between measurements on the physical and virtual systems were used to estimate treatment‐site‐specific safety buffer distances with 0.1%, 0.01%, and 0.001% probability of collision between the gantry and couch or phantom. Plans containing 20 noncoplanar beams to the brain, lung, and prostate optimized via an in‐house noncoplanar radiotherapy platform were converted into XML script for automated delivery and the entire delivery was recorded and timed to demonstrate the feasibility of automated delivery.

Results:

The 3D scanner measured the dimension of the 14 cm cubic phantom within 0.5 mm. The maximal absolute discrepancy between machine and model measurements for gantry‐to‐couch and gantry‐to‐phantom was 0.95 and 2.97 cm, respectively. The reduced accuracy of gantry‐to‐phantom measurements was attributed to phantom setup errors due to the slightly deformable and flexible phantom extremities. The estimated site‐specific safety buffer distance with 0.001% probability of collision for (gantry‐to‐couch, gantry‐to‐phantom) was (1.23 cm, 3.35 cm), (1.01 cm, 3.99 cm), and (2.19 cm, 5.73 cm) for treatment to the head, lung, and prostate, respectively. Automated delivery to all three treatment sites was completed in 15 min and collision free using a digital Linac.

Conclusions:

An individualized collision prediction model for the purpose of noncoplanar beam delivery was developed and verified. With the model, the study has demonstrated the feasibility of predicting deliverable beams for an individual patient and then guiding fully automated noncoplanar treatment delivery. This work motivates development of clinical workflows and quality assurance procedures to allow more extensive use and automation of noncoplanar beam geometries.
Late harvest from Pluto reveals a complex world
Authors: Hand Eric
Published: October 2015

Months after its famed flyby, New Horizons is still giving scientists plenty to ponder.
Challenge faculty to transform STEM learning
Authors: Cooper Melanie M. , Caballero Marcos D. , Ebert-May Diane , Fata-Hartley Cori L. , Jardeleza Sarah E. , Krajcik Joseph S. , Laverty James T. , Matz Rebecca L. , Posey Lynmarie A. , Underwood Sonia M.
Published: October 2015

Focus on core ideas, crosscutting concepts, and scientific practices
Stable inhibitory activity of regulatory T cells requires the transcription factor Helios
Authors: Kim Hye-Jung , Barnitz R. Anthony , Kreslavsky Taras , Brown Flavian D. , Moffett Howell , Lemieux Madeleine E. , Kaygusuz Yasemin , Meissner Torsten , Holderried Tobias A. W. , Chan Susan , Kastner Philippe , Haining W. Nicholas , Cantor Harvey
Published: October 2015

How T cells maintain their identity

Although best known for their pathogen-fighting prowess, T lymphocytes also ensure that the immune response does not run amok. A subset of T cells called regulatory T cells (T
regs
) performs this function by, for example, making sure T cells only attack pathogens and not self. T cells can exhibit plasticity in their functions in the face of an inflammatory stimulus. Kim
et al.
sought to identify the molecules that ensure the stable maintenance of T
regs
. Using genetically modified mice, they found that both CD4
+
and CD8
+
T
regs
require the transcription factor Helios to stably maintain their identity.

Science
, this issue p.
334
Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply
Authors: Olive J.-A. , Behn M. D. , Ito G. , Buck W. R. , Escartín J. , Howell S.
Published: October 2015

Understanding abyssal hill spacing

The most prominent topographic features on Earth are abyssal hills found on the bottom of the ocean floor. Olive
et al.
wanted to understand the spacing and size of these hills. They used a model that combines magma supply and the mechanical response of the crust. The model explains observations of hill spacing around mid-ocean ridges. Crustal topography appears to be a poor recorder of changes in magma supply. However, magma supply changes may be faithfully recorded at the base of the crust.

Science
, this issue p.
310
When sugar is not so sweet
Authors: Boger Dale L.
Published: October 2015

Chemical synthesis of glucosepane promises insights into the role of this molecule in diseases of aging

[Also see Report by

Draghici
et al.

]
Evaluation of the New BD Max GC Real-Time PCR Assay, Analytically and Clinically as a Supplementary Test for the BD ProbeTec GC Qx Amplified DNA Assay, for Molecular Detection of Neisseria gonorrhoeae
Authors: Golparian Daniel , Boräng Stina , Sundqvist Martin , Unemo Magnus
Published: October 2015

The new BD Max GC real-time PCR assay showed high clinical and analytical sensitivity and specificity. It can be an effective and accurate supplementary test for the BD ProbeTec GC Qx amplified DNA assay, which had suboptimal specificity, and might also be used for initial detection of
Neisseria gonorrhoeae
.