bluuebunny/crossref_metadata_2025 huggingface dataset:
A Subscale Experimental Investigation on the Influence of Sanding on Adhesion and Rolling Contact Fatigue of Wheel/Rail Under Water Condition
Authors: Huang Wanliang , Cao Xi , Wen Zefeng , Wang Wenjian , Liu Qiyue , Zhu Minhao , Jin Xuesong
Published: March 2016

With a subscale rolling-sliding apparatus, the objective of this study is to explore the adhesion and rolling contact fatigue characteristics of wheel/rail rollers with sanding under water condition. Sanding improves adhesion coefficient but aggravates the surface damage of wheel and rail materials. With the particle diameter and feed rate increasing, the adhesion coefficient is further improved. However, the surface damage (spalling and pits) becomes severer as well as the surface roughness. Note that pitting is a special damage type when sanding is used to improve the adhesion. Big pits and fatigue cracks appear on subsurface under larger particle diameter and feed rate conditions. Severe cracks initiate from big pits and develop into material to a depth, which results in bulk material breaking.
Investigation of the interface between LPCVD-SiNx gate dielectric and III-nitride for AlGaN/GaN MIS-HEMTs
Authors: Liu Zhaoyang , Huang Sen , Bao Qilong , Wang Xinhua , Wei Ke , Jiang Haojie , Cui Hushan , Li Junfeng , Zhao Chao , Liu Xinyu , Zhang Jinhan , Zhou Qi , Chen Wanjun , Zhang Bo , Jia Lifang
Published: March 2016

The interface between silicon nitride (SiNx) gate dielectric grown by low pressure chemical vapor deposition (LPCVD) and III-nitride heterostructure is investigated by a systematical comparison of AlGaN/GaN high-electron-mobility transistors (HEMTs) and metal-insulator-semiconductor HEMTs (MIS-HEMTs). A 20-nm LPCVD-SiNx grown at 650 °C features a high breakdown E-field of 13 MV/cm and a large conduction-band offset of 2.75 eV to GaN. High ON/OFF current ratio (∼1010) as well as breakdown voltage (∼878 V) is realized by employing the LPCVD-SiNx layer as both the gate and passivation dielectrics. Most important of all, about 2.6 × 1013 cm−2 positive fixed charges are confirmed to be present at the LPCVD-SiNx/III-nitride interface, as revealed by pulsed transfer characterizations and energy-band simulations. The trap density at LPCVD-SiNx/III-nitride interface is also experimentally determined.
Multilevel segmentation of intracranial aneurysms in CT angiography images
Authors: Wang Yan , Zhang Yue , Navarro Laurent , Eker Omer Faruk , Corredor Jerez Ricardo A. , Chen Yu , Zhu Yuemin , Courbebaisse Guy
Published: March 2016

Purpose:

Segmentation of aneurysms plays an important role in interventional planning. Yet, the segmentation of both the lumen and the thrombus of an intracranial aneurysm in computed tomography angiography (CTA) remains a challenge. This paper proposes a multilevel segmentation methodology for efficiently segmenting intracranial aneurysms in CTA images.

Methods:

The proposed methodology first uses the lattice Boltzmann method (LBM) to extract the lumen part directly from the original image. Then, the LBM is applied again on an intermediate image whose lumen part is filled by the mean gray‐level value outside the lumen, to yield an image region containing part of the aneurysm boundary. After that, an expanding disk is introduced to estimate the complete contour of the aneurysm. Finally, the contour detected is used as the initial contour of the level set with ellipse to refine the aneurysm.

Results:

The results obtained on 11 patients from different hospitals showed that the proposed segmentation was comparable with manual segmentation, and that quantitatively, the average segmentation matching factor (SMF) reached 86.99%, demonstrating good segmentation accuracy. Chan–Vese method, Sen's model, and Luca's model were used to compare the proposed method and their average SMF values were 39.98%, 40.76%, and 77.11%, respectively.

Conclusions:

The authors have presented a multilevel segmentation method based on the LBM and level set with ellipse for accurate segmentation of intracranial aneurysms. Compared to three existing methods, for all eleven patients, the proposed method can successfully segment the lumen with the highest SMF values for nine patients and second highest SMF values for the two. It also segments the entire aneurysm with the highest SMF values for ten patients and second highest SMF value for the one. This makes it potential for clinical assessment of the volume and aspect ratio of the intracranial aneurysms.
Benefits of adaptive radiation therapy in lung cancer as a function of replanning frequency
Authors: Dial Christian , Weiss Elisabeth , Siebers Jeffrey V. , Hugo Geoffrey D.
Published: March 2016

Purpose:

To quantify the potential benefit associated with daily replanning in lung cancer in terms of normal tissue dose sparing and to characterize the tradeoff between adaptive benefit and replanning frequency.

Methods:

A set of synthetic images and contours, derived from weekly active breathing control images of 12 patients who underwent radiation therapy treatment for nonsmall cell lung cancer, is generated for each fraction of treatment using principal component analysis in a way that preserves temporal anatomical trends (e.g., tumor regression). Daily synthetic images and contours are used to simulate four different treatment scenarios: (1) a “no‐adapt” scenario that simulates delivery of an initial plan throughout treatment, (2) a “midadapt” scenario that implements a single replan for fraction 18, (3) a “weekly adapt” scenario that simulates weekly adaptations, and (4) a “full‐adapt” scenario that simulates daily replanning. An initial intensity modulated radiation therapy plan is created for each patient and replanning is carried out in an automated fashion by reoptimizing beam apertures and weights. Dose is calculated on each image and accumulated to the first in the series using deformable mappings utilized in synthetic image creation for comparison between simulated treatments.

Results:

Target coverage was maintained and cord tolerance was not exceeded for any of the adaptive simulations. Average reductions in mean lung dose (MLD) and volume of lung receiving 20 Gy or more (V20lung) were 65 ± 49 cGy (p = 0.000 01) and 1.1% ± 1.2% (p = 0.0006), respectively, for all patients. The largest reduction in MLD for a single patient was 162 cGy, which allowed an isotoxic escalation of the target dose of 1668 cGy. Average reductions in cord max dose, mean esophageal dose (MED), dose received by 66% of the heart (D66heart), and dose received by 33% of the heart (D33heart), were 158 ± 280, 117 ± 121, 37 ± 77, and 99 ± 120 cGy, respectively. Average incremental reductions in MLD for the midadapt, weekly adapt, and full‐adapt treatments were 38, 18, and 8 cGy, respectively. Incremental reductions in MED for the same treatments were 57, 37, and 23 cGy. Reductions in MLD and MED for the full‐adapt treatment were correlated with the absolute decrease in the planning target volume (r = 0.34 and r = 0.26).

Conclusions:

Adaptive radiation therapy for lung cancer yields clinically relevant reductions in normal tissue doses for frequencies of adaptation ranging from a single replan up to daily replanning. Increased frequencies of adaptation result in additional benefit while magnitude of benefit decreases.
Ultrasound intima‐media thickness measurement of the carotid artery using ant colony optimization combined with a curvelet‐based orientation‐selective filter
Authors: Li Hao , Zhang Shijie , Ma Rui , Chen Huiren , Xi Shui , Zhang Jue , Fang Jing
Published: March 2016

Purpose:

Automatic measurement of the intima‐media thickness (IMT) from ultrasound carotid images is an important task in clinical diagnosis. Many computer‐based techniques for IMT measurement have been proposed to overcome the limits of manual segmentation. However, the robustness of the algorithms would be influenced by the inherent speckle noise of ultrasound image. This paper proposed a curvelet guided ant colony optimization (CGACO) strategy that could achieve satisfied accuracy for IMT measurement with improved robustness to noise.

Methods:

The curvelet‐based orientation‐selective (CBOS) filter was first introduced for speckle removal and edge enhancement. Different from conventional methods, CBOS filter processes the curvelet coefficients by orientations rather than by magnitude. Then, a specially designed two‐leg ant colony optimization technique, combined with Otsu thresholding and Sobel edge detector, was proposed as a novel segmentation method to extract the media‐adventitia (MA) and the lumen‐intima (LI) boundaries. Finally, a coupled snake model was employed to further smooth the contours of MA and LI.

Results:

In addition to 224 carotid artery images acquired from 34 participants, simulated speckled images with nine levels of noise were also included in the database. The mean absolute distance errors of CGACO for LI interface tracings, MA interface tracings, and IMT measurements were 0.030 ± 0.027, 0.039 ± 0.036, and 0.041 ± 0.036 mm, respectively. Besides, CGACO had a correlation coefficient as high as 0.992 and a bias as low as −0.008. All these measures were comparable to or better than a previous technique and the manual segmentation. On the other hand, CGACO had the highest success rate of 98.7% in the segmentation of real data. It also maintained a much higher success rate in the segmentation of simulated images with different levels of speckle noise.

Conclusions:

The proposed technique showed accurate IMT measurement results. Furthermore, benefiting from the CBOS filter, the robustness to noise of the algorithm was substantially improved. Therefore, CGACO could provide a reliable way to segment the carotid artery from ultrasound images and could be used in clinical practice of IMT measurement, particularly in early atherosclerotic stages.
On band gap predictions for multiresonant metamaterials on plates
Authors: Yoritomo John Y. , Weaver Richard L. , Roux Philippe , Rupin Matthieu , Williams Earl G.
Published: March 2016

Recently wide frequency band gaps were observed in an experimental realization of a multiresonant metamaterial for Lamb waves propagating in thin plates. The band gaps rose from hybridization between the flexural plate (A0 Lamb waves) and longitudinal resonances in rods attached perpendicularly. Shortly thereafter a theory based on considering a one-dimensional periodic array of rods and the scattering matrix for a single rod successfully described the observations. This letter presents an alternative simpler theory, arguably accurate at high rod density, that treats the full two-dimensional array of rods and makes no assumption of periodicity. This theory also fits the measurements.
A cage for pathogens
Authors: Whitehead Kathryn A.
Published: March 2016

A choline and geranate solvent acts as a broad-spectrum antiseptic to wipe out even the most vexing microbial infections.
Discovery of the Elusive UDP-Diacylglucosamine Hydrolase in the Lipid A Biosynthetic Pathway in Chlamydia trachomatis
Authors: Young Hayley E. , Zhao Jinshi , Barker Jeffrey R. , Guan Ziqiang , Valdivia Raphael H. , Zhou Pei
Published: March 2016

Constitutive biosynthesis of lipid A via the Raetz pathway is essential for the viability and fitness of Gram-negative bacteria, including
Chlamydia trachomatis
. Although nearly all of the enzymes in the lipid A biosynthetic pathway are highly conserved across Gram-negative bacteria, the cleavage of the pyrophosphate group of UDP-2,3-diacyl-GlcN (UDP-DAGn) to form lipid X is carried out by two unrelated enzymes: LpxH in beta- and gammaproteobacteria and LpxI in alphaproteobacteria. The intracellular pathogen
C. trachomatis
lacks an ortholog for either of these two enzymes, and yet, it synthesizes lipid A and exhibits conservation of genes encoding other lipid A enzymes. Employing a complementation screen against a
C. trachomatis
genomic library using a conditional-lethal
lpxH
mutant
Escherichia coli
strain, we have identified an open reading frame (Ct461, renamed
lpxG
) encoding a previously uncharacterized enzyme that complements the UDP-DAGn hydrolase function in
E. coli
and catalyzes the conversion of UDP-DAGn to lipid X
in vitro
. LpxG shows little sequence similarity to either LpxH or LpxI, highlighting LpxG as the founding member of a third class of UDP-DAGn hydrolases. Overexpression of LpxG results in toxic accumulation of lipid X and profoundly reduces the infectivity of
C. trachomatis
, validating LpxG as the long-sought-after UDP-DAGn pyrophosphatase in this prominent human pathogen. The complementation approach presented here overcomes the lack of suitable genetic tools for
C. trachomatis
and should be broadly applicable for the functional characterization of other essential
C. trachomatis
genes
.

IMPORTANCE
Chlamydia trachomatis
is a leading cause of infectious blindness and sexually transmitted disease. Due to the lack of robust genetic tools, the functions of many
Chlamydia
genes remain uncharacterized, including the essential gene encoding the UDP-DAGn pyrophosphatase activity for the biosynthesis of lipid A, the membrane anchor of lipooligosaccharide and the predominant lipid species of the outer leaflet of the bacterial outer membrane. We designed a complementation screen against the
C. trachomatis
genomic library using a conditional-lethal mutant of
E. coli
and identified the missing essential gene in the lipid A biosynthetic pathway, which we designated
lpxG
. We show that LpxG is a member of the calcineurin-like phosphatases and displays robust UDP-DAGn pyrophosphatase activity
in vitro
. Overexpression of LpxG in
C. trachomatis
leads to the accumulation of the predicted lipid intermediate and reduces bacterial infectivity, validating the
in vivo
function of LpxG and highlighting the importance of regulated lipid A biosynthesis in
C. trachomatis
.
Excess short-term mortality in women after isolated coronary artery bypass graft surgery
Authors: Filardo Giovanni , Hamman Baron L , Pollock Benjamin D , da Graca Briget , Sass Danielle M , Phan Teresa K , Edgerton James , Prince Syma L , Ring W Steves
Published: March 2016

Objective

Female sex is considered a risk factor for adverse outcomes following isolated coronary artery bypass graft (CABG) surgery. We assessed the association between sex and short-term mortality following isolated CABG, and estimated the ‘excess’ deaths occurring in women.

Methods

Short-term mortality was investigated in 13 327 consecutive isolated CABG patients in North Texas between January 2008 and December 2012. The association between sex and CABG short-term mortality, and the excess deaths among women were assessed via a propensity-adjusted (by Society of Thoracic Surgeons-recognised risk factors) generalised estimating equations model approach.

Results

Short-term mortality was significantly higher in women than men (adjusted OR=1.39; 95% CI 1.04 to 1.86; p=0.027). This significantly greater risk translates into 35 ‘excess’ deaths among women included in this study (>10% of the total 343 deaths in the study cohort) and into 392 ‘excess’ deaths among the ∼40 000 women undergoing isolated CABG in the USA each year.

Conclusions

The higher risk associated with female sex lead to 35 ‘excess’ deaths in women in this study cohort (over 10% of the total deaths) and to 392 ‘excess’ deaths among women undergoing isolated CABG in the USA each year. Further research is needed to assess the causal mechanisms underlying this sex-related difference. Results of such work could inform the development and implementation of sex-specific treatment and management strategies to reduce women's mortality following CABG. Based on our results, if such work brought women's short-term mortality into line with men's, total short-term mortality could be reduced by up to 10%.
Cosmology, cosmic dust, and stellar dimming
Authors: Matthias Chuck. S.
Published: March 2016

A cosmology model is derived, forming an expanding, curved, unbounded, and finite universe resembling a three-dimensional hypersphere with positive curvature. Growth, curvature, and the expansion rate are forced by the initial conditions accompanying the emergence of space and time from the “big bang” singularity. The model generates several variables (past and present stellar distance, luminosity distance, time of emission, photon path, recession velocity, radiation temperature, universe circumference, and Hubble parameter) that are sole functions of redshift, z (readily measured by spectroscopic or photometric means). The model also presents two concepts that replace the need for cosmic inflation and dark energy. Equations for luminosity distance, dL, and Hubble parameter, H, compare extremely well with 28 values of baryon acoustic oscillation measured data over the redshift range 0.07 < z < 2.3. A second data set, compiled by NASA, consists of 27 000 type 1a supernovae measurements of luminosity distance and redshift (0.001 < z < 10). Although the data are extremely scattered, within the scatter is a narrow, well-defined core whose distance, [Formula: see text], exceeds the model value, dL, as redshift increases. The larger distance, [Formula: see text], resulting from a weaker than expected optical signal, is commonly explained as due to an acceleration of universe expansion. Alternatively, if the photons are assumed to be partially quenched by cosmic dust, in proportion to the distance travelled, the weakened core signal can be described by a radiative transfer equation. The resulting equation for [Formula: see text], with an extinction coefficient of 0.000 345 Mpc−1 (or a photon mean free path of 2900 Mpc), fits the core data perfectly.
Pattern of ovulation in the East African root rat (Tachyoryctes splendens) from Tanzania: induced or spontaneous ovulator?
Authors: Katandukila Jestina V. , Bennett Nigel C.
Published: March 2016

The East African root rat (Tachyoryctes splendens (Rüppell, 1835)) is a solitary subterranean rodent that exhibits a marked seasonal reproduction linked to the bimodal rainfall pattern of East Africa. The current study sets out to determine whether the East African root rat is an induced or spontaneous ovulator. Five wild caught adult females were monitored noninvasively for ovarian cyclicity by measuring urinary progesterone every 2 days over a period of 120 days. Females were subjected to three different experimental treatments, namely, initially singly housed or control (C), nonphysical contact with a male (NPC), and physical contact with a vasectomised male (PC), respectively. The concentration of urinary progesterone was higher during PC than during either NPC or C. The act of coitus appears to be necessary for ovulation to occur in the females. The male East African root rats were found to possess epidermal spines on the penis that can be used to bring about cervical stimulation during coitus. The spines result in the induction of ovulation as has been proposed for other solitary subterranean rodents. The findings from the female progesterone profiles and the assessment of penile morphology suggest that the female East African root rat is an induced ovulator stimulated by penile intromission during coitus.
Rapid synthesis and thermoelectric properties of clathrate Ba8Cu6Ge15Si25 by high temperature and high pressure
Authors: Sun Bing , Jia Xiaopeng , Huo Dexuan , Sun Hairui , Zhang Yuewen , Liu Binwu , Liu Haiqiang , Kong Lingjiao , Ma Hongan
Published: March 2016

Ba8Cu6Ge[Formula: see text]Si[Formula: see text] were successfully synthesized by a simple high pressure and high temperature (HPHT) method to investigate the microstructures and thermoelectric (TE) properties. After high pressure synthesis, a highly dense bulk material with lots of fine-layered structure, lattice defects and disorders has been obtained. As expected, the thermal conductivity decreased greatly and the ZT value has been improved significantly, which reaches up to 0.43 at around 773 K. Comparing with other methods, HPHT could shorten the synthesis time from several days to half an hour. It reveals that the HPHT method will become an effective approach for optimizing the TE performance of these materials.
Nuclear lattice simulations and SU(4) symmetry
Authors: Lee Dean
Published: March 2016

We discuss the theory and computational algorithms involved in nuclear lattice simulations using chiral effective field theory. We elucidate the role of Wigner’s SU(4) symmetry and the role it plays in alpha clustering and rendering the auxiliary-field projection Monte Carlo simulations tractable.
Mineralization of the South Pennine Orefield, UK—A Review
Authors: Ford T.D. , Worley N.E.
Published: March 2016

This review of the South Pennine Orefield (SPO) draws together the findings from many years of underground field observations and petrographical study. Mineralization is of the Mississippi Valley-type (MVT) and is concentrated within an area of some 200 km
2
, mainly along the eastern margins of a large inlier, the Derbyshire High, in Carboniferous platform carbonate host rocks. The inlier covers some 390 km
2
, forms an up-dip promontory of a larger structure, the East Midlands Shelf, and is surrounded by shales and sandstones of the Millstone Grit and Pennine Coal Measures groups. Mineralization probably began during the late Westphalian (Moscovian, Mid Pennsylvanian), when subsidence due to thermal sag resulted in the limestone being buried to depths of
c.
4 km beneath younger strata. A palaeohydraulic reconstruction is presented from analysis of mineralized palaeokarst features, which are interpreted as representing hypogenic or deep-seated karst formed by the interstratal circulation of hydrothermal water in a mostly confined hydrodynamic setting. It is reasoned that Variscan inversion of N–S faults to the east of the SPO resulted in erosion of Namurian and Westphalian (Upper Mississippian–Middle Pennsylvanian) rocks and created a hydraulic gradient inclined towards the south-west. Acidic F-Ba-Pb-Zn enriched fluid evolved in the Namurian basinal rocks and migrated into fractured limestone. The resultant wall-rock dissolution along existing wrench faults led to the formation of a maze of stratiform mineral deposits (flats) and more irregular spongework-shaped structures (pipes). The presence of hydrocarbon accumulations in the limestones and evidence from fluid inclusions indicates that the mineralizing fluids were chloride/fluoride-rich and compositionally typical of oilfield brine. Isotope evidence demonstrates a sulphate evaporite source of sulphur, mainly from the Chadian (Visean, Middle Mississippian) Middleton Anhydrite Formation. By the late Cenozoic, karstification of exposed carbonate rocks began and the current pattern of epigenic karst drainage started to develop as the regional hydraulic gradient reversed, assuming its present eastward inclined attitude. The mineralized hypogenic karst was overprinted by later drainage systems as the hydraulic gradient changed, and placer deposits were formed from the erosion of existing mineralization. This was accompanied by circulation of meteoric water and resulted in the supergene weathering of the sulphide ore minerals. Eastward underflow of meteoric groundwater also exploited the same mineralization flow paths. There is evidence that pre-mineralization hypogenic karst was also significant in the formation of orebodies in the North Pennine Orefield and the Halkyn–Minera Orefield of NE Wales.
Modality-Dependent Cross-Media Retrieval
Authors: Wei Yunchao , Zhao Yao , Zhu Zhenfeng , Wei Shikui , Xiao Yanhui , Feng Jiashi , Yan Shuicheng
Published: March 2016

In this article, we investigate the cross-media retrieval between images and text, that is, using image to search text (I2T) and using text to search images (T2I). Existing cross-media retrieval methods usually learn one couple of projections, by which the original features of images and text can be projected into a common latent space to measure the content similarity. However, using the same projections for the two different retrieval tasks (I2T and T2I) may lead to a tradeoff between their respective performances, rather than their best performances. Different from previous works, we propose a modality-dependent cross-media retrieval (MDCR) model, where two couples of projections are learned for different cross-media retrieval tasks instead of one couple of projections. Specifically, by jointly optimizing the correlation between images and text and the linear regression from one modal space (image or text) to the semantic space, two couples of mappings are learned to project images and text from their original feature spaces into two common latent subspaces (one for I2T and the other for T2I). Extensive experiments show the superiority of the proposed MDCR compared with other methods. In particular, based on the 4,096-dimensional convolutional neural network (CNN) visual feature and 100-dimensional Latent Dirichlet Allocation (LDA) textual feature, the mAP of the proposed method achieves the mAP score of 41.5%, which is a new state-of-the-art performance on the Wikipedia dataset.
GNL is not Linux
Authors: Neville-Neil George V.
Published: March 2016

What's in a name?
Existing technologies can assist the disabled
Authors: Kirkpatrick Keith
Published: March 2016

Researchers consider how to adapt broadly available technology products for those battling physical impairments.
Secure multiparty computations on Bitcoin
Authors: Andrychowicz Marcin , Dziembowski Stefan , Malinowski Daniel , Mazurek Łukasz
Published: March 2016

Is it possible to design an online protocol for playing a lottery, in a completely decentralized way, that is, without relying on a trusted third party? Or can one construct a fully decentralized protocol for selling secret information, so that neither the seller nor the buyer can cheat in it? Until recently, it seemed that every online protocol that has financial consequences for the participants needs to rely on some sort of a trusted server that ensures that the money is transferred between them. In this work, we propose to use Bitcoin (a digital currency, introduced in 2008) to design such fully decentralized protocols that are secure even if no trusted third party is available. As an instantiation of this idea, we construct protocols for secure multiparty lotteries using the Bitcoin currency, without relying on a trusted authority. Our protocols guarantee fairness for the honest parties no matter how the loser behaves. For example, if one party interrupts the protocol, then her money is transferred to the honest participants. Our protocols are practical (to demonstrate it, we performed their transactions in the actual Bitcoin system) and in principle could be used in real life as a replacement for the online gambling sites.
The Social Context of Decisions
Authors: Larrick Richard P.
Published: March 2016

The past 40 years of psychological research on decision making has identified a number of important cognitive biases. However, the psychological study of decision making tends to focus on individuals making decisions in isolation. This article explores the social context of individual decision making by considering three lenses: individual contributions in social decision processes, individuals as social products, and individuals as sources of social preferences. The social context of decision making both improves decision making by allowing diverse knowledge to be pooled and creates shared perspectives—including shared blind spots. The article offers conjectures on managerial insight about social settings that can inform future research.
Skeletal muscle glucose uptake during treadmill exercise in neuronal nitric oxide synthase-μ knockout mice
Authors: Hong Yet Hoi , Yang Christine , Betik Andrew C. , Lee-Young Robert S. , McConell Glenn K.
Published: March 2016

Nitric oxide influences intramuscular signaling that affects skeletal muscle glucose uptake during exercise. The role of the main NO-producing enzyme isoform activated during skeletal muscle contraction, neuronal nitric oxide synthase-μ (nNOSμ), in modulating glucose uptake has not been investigated in a physiological exercise model. In this study, conscious and unrestrained chronically catheterized nNOSμ+/+ and nNOSμ−/− mice either remained at rest or ran on a treadmill at 17 m/min for 30 min. Both groups of mice demonstrated similar exercise capacity during a maximal exercise test to exhaustion (17.7 ± 0.6 vs. 15.9 ± 0.9 min for nNOSμ+/+ and nNOSμ−/−, respectively, P > 0.05). Resting and exercise blood glucose levels were comparable between the genotypes. Very low levels of NOS activity were detected in skeletal muscle from nNOSμ−/− mice, and exercise increased NOS activity only in nNOSμ+/+ mice (4.4 ± 0.3 to 5.2 ± 0.4 pmol·mg−1·min−1, P < 0.05). Exercise significantly increased glucose uptake in gastrocnemius muscle (5- to 7-fold) and, surprisingly, more so in nNOSμ−/− than in nNOSμ+/+ mice ( P < 0.05). This is in parallel with a greater increase in AMPK phosphorylation during exercise in nNOSμ−/− mice. In conclusion, nNOSμ is not essential for skeletal muscle glucose uptake during exercise, and the higher skeletal muscle glucose uptake during exercise in nNOSμ−/− mice may be due to compensatory increases in AMPK activation.
Enhancing theJournal
Authors: Sharkey Keith A
Published: March 2016

The Canadian Journal of Gastroenterologycontinues to grow in strength as a national journal of importance to gastroenterologists and hepatologists. As the official journal of both the Canadian Association of Gastroenterolgy and the Canadian Association for the Study of the Liver, it also serves as an important tool for the dissemination of guidelines and standards for the entire medical community in Canada. We should be proud of these accomplishments. But one also needs to ask, can theJournalbe better? Is there something more that can be achieved? Some would say the status quo is fine. But realistically, we regularly look to the journals of our sister associations in the United States and the United Kingdom -Gastroenterology, HepatologyandGut- for the latest and best in our field. So, I would argue, we can achieve more and make theJournalbetter.
Verrucous Carcinoma of the Esophagus Eluding Multiple Sets of Endoscopic Biopsies and Endoscopic Ultrasound: A Case Report and Review of the Literarure
Authors: Devlin Shane , Falck Vincent , Urbanski Stefan J , Mitchell Philip , Romagnuolo Joseph
Published: March 2016

A 56-year-old woman was noted to have a 5 cm to 6 cm long, irregular narrowing of the distal esophagus on an upper gastrointestinal series. Initial endoscopy revealed a polypoid mass in the distal esophagus and concurrent endoscopic ultrasound revealed changes typical of inflammation but no evidence of an obvious neoplastic process. Repeated biopsies revealed only inflammation with no evidence of malignancy. Only after prolonged acid suppression did biopsies reveal verrucous carcinoma of the esophagus. The patient underwent a trans-hiatal esophagectomy and has remained well with no evidence of progression since. Verrucous carcinoma is a rare variant of squamous cell carcinoma, taking on a papillary or warty appearance grossly. Histological diagnosis may be difficult because this tumour typically shows no high-grade dysplasia. Therefore, diagnosis can be challenging, often requiring multiple sets of endoscopic biopsies due to the overlying hyperkeratotic layer. Of the 20 cases that have been reported, this is the second to provide an endosonographic description and the first to describe a change in endoscopic appearance with acid suppression.
Effects ofHelicobacter pyloriWater Extract on Expression of Endothelial Adhesion Molecules
Authors: Yoshida Norimasa , Kassai Kyoichi , Murase Hironobu , Tanaka Yukiko , Kokura Satoshi , Ichikawa Hiroshi , Naito Yuji , Okanoue Takeshi , Yoshikawa Toshikazu
Published: March 2016

The present study investigated whetherHelicobacter pyloriwater extract induces the upregulation of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin on human umbilical vein endothelial cells, using an ELISA. The nature of the substances mediating this upregulation was also analyzed.H pyloriwater extract derived from type strain (NCTC 11637) significantly upregulated intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin to the same extent as interleukin-1. Treatments with extracts from clinical strains showed no significant increases in expression of these adhesion molecules. In a fractionation study, approximately 7 kDa fraction showed peak activity. This activity was tolerant to heating and trypsin digestion. These results indicate thatH pyloriwater extract contains water-soluble, low-molecular, nonprotein substances which induce upregulation of adhesion molecules on human umbilical vein endothelial cells, suggesting that products ofH pylorimay elicit gastric mucosal inflammation by promoting expression of endothelial adhesion molecules.
Octreotide in Intestinal Lymphangiectasia: Lack of a Clinical Response and Failure to Alter Lymphatic Function in a Guinea Pig Model
Authors: Makhija S , vod der Weid P-Y , Meddings J , Urbanski SJ , Beck PL
Published: March 2016

Intestinal lymphangiectasia, which can be classified as primary or secondary, is an unusual cause of protein-losing enteropathy. The main clinical features include edema, fat malabsorption, lymphopenia and hypoalbuminemia. Clinical management generally includes a low-fat diet and supplementation with medium chain triglycerides. A small number of recent reports advocate the use of octreotide in intestinal lymphangiectasia. It is unclear why octreotide was used in these studies; although octreotide can alter splanchnic blood flow and intestinal motility, its actions on lymphatic function has never been investigated. A case of a patient with intestinal lymphangiectasia who required a shunt procedure after failing medium chain triglycerides and octreotide therapy is presented. During the management of this case, all existing literature on intestinal lymphangiectasia and all the known actions of octreotide were reviewed. Because some of the case reports suggested that octreotide may improve the clinical course of intestinal lymphangiectasia by altering lymphatic function, a series of experiments were undertaken to assess this. In an established guinea pig model, the role of octreotide in lymphatic function was examined. In this model system, the mesenteric lymphatic vessels responded to 5-hydroxytryptamine with a decrease in constriction frequency, while histamine administration markedly increased lymphatic constriction frequency. Octreotide failed to produce any change in lymphatic function when a wide range of concentrations were applied to the mesenteric lymphatic vessel preparation. In conclusion, in this case, octreotide failed to induce a clinical response and laboratory studies showed that octreotide did not alter lymphatic function. Thus, the mechanisms by which octreotide induced clinical responses in the cases reported elsewhere in the literature remain unclear, but the present study suggests that it does not appear to act via increasing lymphatic pumping.
Costs of Finding an Advanced Adenoma in Colorectal Screening
Authors: Simon Jerome B
Published: March 2016

The authors used computerized decision analysis to estimate the costs of finding and removing an advanced colonic adenoma in patients referred because of a positive fecal occult blood test. An advanced adenoma was defined as a villous adenoma, a tubular adenoma 10 mm or more in size, or a lesion that harboured highgrade dysplasia or cancer. Four strategies were compared: flexible sigmoidoscopy, flexible sigmoidoscopy plus air contrast barium enema, virtual colonoscopy (CT colography) and colonoscopy. Colonoscopy with polypectomy was undertaken if any of the methods detected a polyp. Probabilities and test characteristics were determined from the literature, and costs were estimated from the provincial fee schedule (Ontario) and local hospital sources. With an assumed 17% probability of an advanced adenoma being present, sigmoidoscopy was the most cost effective strategy at $1930 to find and clear an advanced lesion, but the procredure missed between one-third and almost one-half of the lesions, depending on the depth of insertion. At $2290, colonoscopy was slightly more expensive than sigmoidoscopy and more cost effective than either sigmoidoscopy plus barium enema ($2840) or virtual colonoscopy ($3681), neither of which detected as many advanced adenomas. The authors concluded that colonoscopy is the preferred investigative strategy and that improved access to colonoscopy is an important goal for occult blood screening programs.
Celiac Disease: Diagnosis at Laparoscopy
Authors: Rosendaal Guido MA Van , Temple Walley J
Published: March 2016

A 27-year-old woman was found to have an abnormal small bowel at the time of an elective laparoscopic tubal ligation. Subsequent investigation revealed celiac disease to be the underyling cause. The changes identified are believed to reflect an increased intestinal blood flow, which has been identified in the diagnostic imaging literature to be associated with active celiac disease. Further study of this feature of celiac disease may provide additional insights into its pathophysiology.
Control the Epithelial Barrier: A Pivotal First Line of Defense
Authors: McKay Catherine M , McKay Derek M
Published: March 2016

Lumen-derived material gains access to the mucosa by permeating between adjacent epithelial cells (ie, paracellular pathway), by transcytosis across the apical and basolateral cell membranes (ie, transcellular pathway) or by exploiting breaks or erosions in the epithelium that may, for example, result from inflammation. Increased epithelial permeability (or decreased barrier function) has repeatedly been demonstrated in a variety of gut disturbances; notably, in inflammatory bowel disease (IBD). There has been an exponential increase in our knowledge of the structural elements that comprise the epithelial barrier, and of the intrinsic factors (eg, cytokines) and external stimuli (eg, bacterial toxins) that can either perturb or enhance epithelial permeability. Canadian researchers have been very active in the study of epithelial permeability and have been responsible for major advances in the field, documenting increased permeability in patients with ulcer disease and IBD and some of their first degree relatives (as well as before onset of overt inflammation), and elucidating mechanisms of stress-induced and cytokine-induced increases in permeability (1-8). A recent study from Scott et al (9) continues this impressive tradition.
Probiotics and Lactose Maldigestion
Authors: Sherman Philip M
Published: March 2016

Lactic acid-producing bacteria have long been employed in the preparation of a variety of foods and beverages, and are taken on a regular basis by asymptomatic individuals in many parts of the world in an effort to promote and maintain health. More recently, there has been increasing interest in the role of feeding nonpathogenic, viable bacteria to domesticated animals and humans to prevent and treat a variety of intestinal diseases (1) and extradigestive conditions (2).
Reflections of the Outgoing President of the CAG
Authors: Sherman Philip M
Published: March 2016

With the completion of a highly successful Canadian Digestive Disease Week (CDDW) in Banff earlier this month, the leadership of the Canadian Association of Gastroenterology (CAG) has been replaced in an orderly and planned fashion. It has been my honour to serve as the President of the CAG for the past two years. I trust that you will judge that some progress has been made and that not too many errors have occurred during my tenure as the 39th President of the CAG.
Capsule Endoscopy: A Single Centre Experience with the First 226 Capsules
Authors: Enns R , Go K , Chang H , Pluta K
Published: March 2016

BACKGROUND:Capsule endoscopy (CE) refers to a novel diagnostic method of imaging the gastrointestinal tract using a wireless capsule that transmits images to a data recorder while the device traverses the small intestine.

OBJECTIVE:To review the authors' experience with CE to determine the indications, outcomes and management of positive findings.

METHODS:Patients were prepared for CE with a single dose of magnesium citrate. Following an 8 h fast, a sensor array system was applied to the abdomen, the capsule was swallowed and the images were transmitted to a data recorder worn on the patient's side. Typically, the battery life of the capsule is 8 h, following which the data recorder is returned, downloaded to a computer workstation and reviewed.

RESULTS:To date, 226 capsule studies have been performed in 209 patients. The indications included obscure bleeding (167 studies: 88 overt, 79 occult), anemia (14 studies), evaluation for inflammatory bowel disease (12 studies), screening for polyps (10 studies), pain (19 studies) and abnormal radiological imaging (4 studies). In the setting of obscure bleeding, a definitive source of bleeding was discovered in 85 studies. This included angiodysplasia (52 studies), mitotic lesions (10 studies) and ulcers (23 studies). A probable source of bleeding was found in another 10 capsule studies. In the setting of anemia without evidence of bleeding, the definitive findings included ulcers (three studies), angiodysplasia (two studies), mitotic lesions (one study) and celiac disease (one study). Of four patients with abnormal radiological imaging, CE demonstrated lesions in two. The results of 35 capsule studies led to laparotomy with curative surgical resection. In eight studies, the capsules became lodged within a stricture; none led to obstruction and three were managed endoscopically.

CONCLUSION:The yield of CE in carefully selected patients with obscure bleeding approximates 51%. There appear to be few complications, and patient satisfaction appears high. Cost analysis and further studies of clinical outcomes are required to elucidate appropriate indications for this device.
The Quebec Association of Gastroenterology Position Paper on Colorectal Cancer Screening - 2003
Authors: Barkun AN , Jobin G , Cousineau G , Dubé S , Lahaie R , Paré P , Stein B , Wassef R
Published: March 2016

Colorectal cancer is a leading cause of death and the third most common cancer in Canada. Evidence suggests that screening can reduce mortality rates and the cost effectiveness of a program compares favourably with initiatives for breast and cervical cancer. The objectives of the Association des gastro-entérologues du Québec Task Force were to determine the need for a policy on screening for colorectal cancer in Quebec, to evaluate the testing methods available and to propose one or more of these alternatives as part of a formal screening program, if indicated. Fecal occult blood testing (FOBT), endoscopy (including sigmoidoscopy and colonoscopy), barium enema and virtual colonoscopy were considered. Although most clinical efficacy data are available for FOBT and sigmoidoscopy, there are limitations to programs based on these strategies. FOBT has a high false positive rate and a low detection yield, and even a combination of these strategies will miss 24% of cancers. Colonoscopy is the best strategy to both detect and remove polyps and to diagnose colorectal cancer, with double contrast barium enema also being a sensitive detection method. The Task Force recommended the establishment, in Quebec, of a screening program with five- to 10-yearly double contrast barium enema or 10-yearly colonoscopy for individuals aged 50 years or older at low risk. The program should include outcome monitoring, public and professional education to increase awareness and promote compliance, and central coordination with other provincial programs. The program should be evaluated; specific billing codes for screening for colorectal cancer would help facilitate this. Formal feasibility, effectiveness and cost-effectiveness studies in Quebec are now warranted.
Standards of Care: Management of Patients with Nonvariceal Upper Gastrointestinal Hemorrhage
Authors: Van Rosendaal Guido
Published: March 2016

This article is the outcome of a formal process of clinical guideline development involving 25 participants with expertise covering a wide range of disciplines and nationalities, as well as nonvoting observers representing Health Canada and seven industry sponsors. Twenty recommendations are presented, each specifying the degree of support and dissention expressed in the panel's votes. One hundred ninety-two references are cited. Early endoscopy and risk stratification are central strategies in the framework provided.
Redefining Lactose as a Conditional Prebiotic
Authors: Szilagyi Andrew
Published: March 2016

Lactose in dairy products is maldigested by up to 70% to 75% of the world's population and many people may therefore suffer symptoms reminiscent of irritable bowel syndrome. As a result, most research to date has concentrated on ways of improving lactose tolerance to enhance dairy as a source of nutrition. However, research on other possible benefits of lactose and its maldigestion has lagged. In view of an exponential growth in the understanding of intestinal microfloral host interactions and the expanding therapeutical potential of probiotics, a reassessment of the role of lactose as a potential prebiotic in lactase nonpersistent subjects is required. Gibson and Roberfroid introduced the concept of prebiotics and outlined definitive requirements for such a compound. The present article examines scientific and clinical knowledge about the properties of lactose and argues that in lactase nonpersistent subjects, lactose qualifies as a prebiotic.
Teaching Ethics in Canadian Gastroenterology
Authors: Van Rosendaal Guido
Published: March 2016

A firm foundation in medical bioethics is essential to the education of any physician. The relative importance of specific ethical principles may vary with the physician's specialty, depending on the nature of the problems dealt with or the services provided in each discipline. The working knowledge in ethics required of a gastroenterologist is different, for example, from that needed by an intensivist or a psychiatrist. It is with this context in mind that Malhotra and Ottaway, in this issue of theJournal(pages 315-317), propose the creation of a national curriculum in bioethics specific to gastroenterology.
Commentary: Bone Density in Women with Inflammatory Bowel Disease
Authors: Steinhart A Hillary
Published: March 2016

Conventional wisdom suggests that children who develop inflammatory bowel disease are at particularly increased risk of osteopenia and osteoporosis because of the effects of disease activity, nutritional factors and medications, especially glucocorticoids, during critical periods of bone growth. In this study, Bernstein et al endeavoured to determine the prevalence of reduced bone mineral density (BMD) in a population-based cohort of women with onset of inflammatory bowel disease (IBD) before 20 years of age. A secondary goal of the study was to compare estimates of the rates of osteopenia and osteoporosis using two different techniques: the more conventional areal BMD and volumetric BMD. The latter measure is designed to account for the reduction in bone size that can occur because of growth delay associated with childhood IBD. On the other hand, areal BMD is said to underestimate true bone density. The authors identified a cohort of patients using their research registry of IBD patients in Manitoba. Women who developed IBD before 20 years of age and who were younger than age 45 at the time of the study were invited to complete a questionnaire and undergo dual energy x-ray absorptiometry (DEXA). Of the 148 subjects who were approached, 70 were eligible and agreed to participate. More than 80% of the participating subjects had Crohn's disease (CD) and more than 80% affected had onset of disease after puberty. BMD did not appear to differ between the patients with prepubertal and those with postpubertal onset. Twenty-five of the 70 subjects had an areal T score less than -1 at one or more site. Only three had osteoporosis (T score less than -2.5). Individuals with a T score less than -1 had lower body weight and were more likely than other patients to have experienced amenorrhea in the year prior to DEXA testing. When T scores were adjusted for abnormalities in bone size, the mean volumetric T score was slightly but statistically significantly higher than the corresponding areal T score at each site.