bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Consequences of Marijuana
Authors: Khalsa Jag H. , Genser Sander , Francis Henry , Martin Billy
Published: January 2014

As documented in national surveys, for the past several years, marijuana has been the most commonly abused drug in the United States, with approximately 6% of the population 12 years and older having used the drug in the month prior to interview. The use of marijuana is not without significant health hazards. Marijuana is associated with effects on almost every organ system in the body, ranging from the central nervous system to the cardiovascular, endocrine, respiratory/pulmonary, and immune systems. Research presented in this special supplement will show that in addition to marijuana abuse/dependence, marijuana use is associated in some studies with impairment of cognitive function in the young and old, fetal and developmental consequences, cardiovascular effects (heart rate and blood pressure changes), respiratory/pulmonary complications such as chronic cough and emphysema, impaired immune function leading to vulnerability to and increased infections, and the risk of developing head, neck, and/or lung cancer. In general, acute effects are better studied than those of chronic use, and more studies are needed that focus on disentangling effects of marijuana from those of other drugs and adverse environmental conditions.
Development and Consequences of Cannabis Dependence
Authors: Budney Alan J. , Moore Brent A.
Published: January 2014

The past 10 to 15 years of clinical and basic research have produced strong evidence demonstrating that cannabis can and does produce dependence. Clinical and epidemiological studies indicate that cannabis dependence is a relatively common phenomenon associated with significant psychosocial impairment. Basic research has identified a neurobiological system specific to the actions of cannabinoids. Human and nonhuman studies have demonstrated a valid withdrawal syndrome that is relatively common among heavy marijuana users. Last, clinical trials evaluating treatments for cannabis dependence suggest that this disorder, like other substance dependence disorders, is responsive to intervention, yet the majority of patients have difficulty achieving and maintaining abstinence. Of concern, treatment seeking for marijuana dependence has increased almost twofold over the past 10 years. This report briefly reviews selected research literature relevant to our current understanding of cannabis dependence, its associated consequences, and treatment efficacy.
Marijuana Smoking and Head and Neck Cancer
Authors: Hashibe Mia , Ford Daniel E. , Zhang Zuo‐Feng
Published: January 2014

A recent epidemiological study showed that marijuana smoking was associated with an increased risk of head and neck cancer. Among high school students and young adults, the prevalence of marijuana use was on the rise in the 1990s, with a simultaneous decline in the perception that marijuana use is harmful. It will be a major public health challenge to make people aware of the harmful effects of marijuana smoking, when some people view it as the illicit drug with the least risk. The carcinogenicity of Δ9‐tetrahydrocannabinol (THC) is not clear, but according to laboratory studies, it appears to have antitumor properties such as apoptosis as well as tumor‐promoting properties such as limiting immune function and increasing reactive oxygen species. Marijuana tar contains similar carcinogens to tar from tobacco cigarettes, but each marijuana cigarette may be more harmful than a tobacco cigarette since more tar is inhaled and retained when smoking marijuana. More molecular alterations have been observed in bronchial mucosa specimens of marijuana smokers compared to nonsmokers. Field cancerization may be occurring on the bronchial epithelium due to marijuana smoking exposure. Several case studies were suggestive of an association of marijuana smoking with head and neck cancers and oral lesions. However, in a cohort study with 8 years of follow‐up, marijuana use was not associated with increased risks of all cancers or smoking‐related cancers. Further epidemiological studies are necessary to confirm the association of marijuana smoking with head and neck cancers and to examine marijuana smoking as a risk factor for lung cancer. It will also be of interest to examine potential field cancerization of the upper aerodigestive tract by marijuana and to explore marijuana as a risk factor for oral premalignant lesions.
A longitudinal study assessing lens thickness changes in the eye of the growing beagle using ultrasound scanning: relevance to age of dogs in regulatory toxicology studies
Authors: Maynard Juliana , Sykes Angela , Powell Helen , Healing Guy , Scott Marietta , Holmes Andrew , Ricketts Sally‐Ann , Stewart Jane , Davis Stewart
Published: January 2014

The lens is formed in utero with new secondary lens fibres added as outer layers throughout life in a growth pattern characteristic of the species. This study examined the time course of beagle lens growth to better understand the optimal starting age of dogs for safety studies to support adult versus paediatric indications, and to assess the feasibility of non‐invasively monitoring lens growth with high frequency ultrasound. Ultrasound scanning was performed in six female beagle dogs using the Vevo770. All dogs were imaged in B‐mode using local anaesthetic but without sedation. Imaging was carried out every 2 weeks from 8 to 22 weeks of age and then monthly until 62 weeks of age. The dogs tolerated the procedure well. The lens was visible in all dogs and measuring the lens thickness with high frequency ultrasound demonstrated good analytical reproducibility [Root Mean Square (RMS) = 3.13%]. No differences between the left and right eye existed and lens thickness correlated with body weight. The highest weekly growth rate was before 12 weeks of age. A statistically significant difference between monthly thickness was detected until 42 weeks of age at which point growth reached a plateau. During the experiment, lenses grew by 29.7% reaching an average thickness of 6.4 mm ± 0.03. By 10 months of age (the typical age used for routine toxicological evaluation), beagles have reached a plateau in lens growth that is analogous to human adults. Where lens is a target organ of concern it is suggested that beagles under 6 months old may be a better model for determining paediatric safety. Copyright © 2014 John Wiley & Sons, Ltd.
Osteoporosis Screening in Postmenopausal Women 50 to 64 Years Old: Comparison of US Preventive Services Task Force Strategy and Two Traditional Strategies in the Women's Health Initiative
Authors: Crandall Carolyn J , Larson Joseph , Gourlay Margaret L , Donaldson Meghan G , LaCroix Andrea , Cauley Jane A , Wactawski-Wende Jean , Gass Margery L , Robbins John A , Watts Nelson B , Ensrud Kristine E
Published: January 2014

The US Preventive Services Task Force (USPSTF) recommends osteoporosis screening for women younger than 65 years whose 10-year predicted risk of major osteoporotic fracture is ≥9.3%. For identifying screening candidates among women aged 50 to 64 years, it is uncertain how the USPSTF strategy compares with the Osteoporosis Self-Assessment Tool (OST) and the Simple Calculated Osteoporosis Risk Estimate (SCORE). We examined data (1994 to 2012) from 5165 Women's Health Initiative participants aged 50 to 64 years. For the USPSTF (Fracture Risk Assessment Tool [FRAX] major fracture risk ≥9.3% calculated without bone mineral density [BMD]), OST (score <2), and SCORE (score >7) strategies, we assessed sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) to discriminate between those with and without femoral neck (FN) T-score ≤−2.5. Sensitivity, specificity, and AUC for identifying FN T-score ≤−2.5 were 34.1%, 85.8%, and 0.60 for USPSTF (FRAX); 74.0%, 70.8%, and 0.72 for SCORE; and 79.8%, 66.3%, and 0.73 for OST. The USPSTF strategy identified about one-third of women aged 50 to 64 years with FN T-scores ≤−2.5. Among women aged 50 to 64 years, the USPSTF strategy was modestly better than chance alone and inferior to conventional SCORE and OST strategies in discriminating between women with and without FN T-score ≤−2.5. © 2014 American Society for Bone and Mineral Research.
Gene delivery in malignant B cells using the combination of lentiviruses conjugated to anti‐transferrin receptor antibodies and an immunoglobulin promoter
Authors: Leoh Lai Sum , Morizono Kouki , Kershaw Kathleen M. , Chen Irvin S. Y. , Penichet Manuel L. , Daniels‐Wells Tracy R.
Published: January 2014

Background

We previously developed an antibody‐avidin fusion protein (ch128.1Av) specific for the human transferrin receptor 1 (TfR1; CD71) to be used as a delivery vector for cancer therapy and showed that ch128.1Av delivers the biotinylated plant toxin saporin‐6 into malignant B cells. However, as a result of widespread expression of TfR1, delivery of the toxin to normal cells is a concern. Therefore, we explored the potential of a dual targeted lentiviral‐mediated gene therapy strategy to restrict gene expression to malignant B cells. Targeting occurs through the use of ch128.1Av or its parental antibody without avidin (ch128.1) and through transcriptional regulation using an immunoglobulin promoter.

Methods

Flow cytometry was used to detect the expression of enhanced green fluorescent protein (EGFP) in a panel of cell lines. Cell viability after specific delivery of the therapeutic gene FCU1, a chimeric enzyme consisting of cytosine deaminase genetically fused to uracil phosphoribosyltransferse that converts the 5‐fluorocytosine (5‐FC) prodrug into toxic metabolites, was monitored using the MTS or WST‐1 viability assay.

Results

We found that EGFP was specifically expressed in a panel of human malignant B‐cell lines, but not in human malignant T‐cell lines. EGFP expression was observed in all cell lines when a ubiquitous promoter was used. Furthermore, we show the decrease of cell viability in malignant plasma cells in the presence of 5‐FC and the FCU1 gene.

Conclusions

The present study demonstrates that gene expression can be restricted to malignant B cells and suggests that this dual targeted gene therapy strategy may help to circumvent the potential side effects of certain TfR1‐targeted protein delivery approaches. Copyright © 2014 John Wiley & Sons, Ltd.
Automatic detection of anatomical landmarks on the knee joint using MRI data
Authors: Xue Ning , Doellinger Michael , Ho Charles P. , Surowiec Rachel K. , Schwarz Raphael
Published: January 2014

Purpose

To propose a new automated learning‐based scheme for locating anatomical landmarks on the knee joint using three‐dimensional (3D) MR image data.

Materials and Methods

This method makes use of interest points as candidates for landmarks. All candidates are evaluated by a “coarse to fine” 3D feature descriptor computed from manually placed landmarks in training datasets. The results are refined using a multi‐classifier boosting system. We demonstrate our method by the detection of 24 landmarks on the knee joint of 35 subjects. To verify the robustness, the test datasets differ in contrast, resolution, patient positioning, and health condition of the knee joint. The proposed method is evaluated by measuring the distance between manually placed landmarks and automatically detected landmarks and the computational cost for detecting one landmark in a 3D dataset.

Results

The results reveal that the method is capable of localizing landmarks with a reasonable accuracy (1.64 ± 1.03 mm [mean ± standard deviation]), sensitivity (97%) and run time efficiency (4.82 s).

Conclusion

This study suggests that the proposed method is an accurate and robust approach for the automated landmark detection in various MR datasets. The proposed method can be used as the initialization or constraint in higher level medical image processing workflows such as in kinematic description, segmentation and registration. J. Magn. Reson. Imaging 2015;41:183–192. © 2013 Wiley Periodicals, Inc.
Validation of volumetric and single‐slice MRI adipose analysis using a novel fully automated segmentation method
Authors: Addeman Bryan T. , Kutty Shelby , Perkins Thomas G. , Soliman Abraam S. , Wiens Curtis N. , McCurdy Colin M. , Beaton Melanie D. , Hegele Robert A. , McKenzie Charles A.
Published: January 2014

Purpose

To validate a fully automated adipose segmentation method with magnetic resonance imaging (MRI) fat fraction abdominal imaging. We hypothesized that this method is suitable for segmentation of subcutaneous adipose tissue (SAT) and intra‐abdominal adipose tissue (IAAT) in a wide population range, easy to use, works with a variety of hardware setups, and is highly repeatable.

Materials and Methods

Analysis was performed comparing precision and analysis time of manual and automated segmentation of single‐slice imaging, and volumetric imaging (78–88 slices). Volumetric and single‐slice data were acquired in a variety of cohorts (body mass index [BMI] 15.6–41.76) including healthy adult volunteers, adolescent volunteers, and subjects with nonalcoholic fatty liver disease and lipodystrophies. A subset of healthy volunteers was analyzed for repeatability in the measurements.

Results

The fully automated segmentation was found to have excellent agreement with manual segmentation with no substantial bias across all study cohorts. Repeatability tests showed a mean coefficient of variation of 1.2 ± 0.6% for SAT, and 2.7 ± 2.2% for IAAT. Analysis with automated segmentation was rapid, requiring 2 seconds per slice compared with 8 minutes per slice with manual segmentation.

Conclusion

We demonstrate the ability to accurately and rapidly segment regional adipose tissue using fat fraction maps across a wide population range, with varying hardware setups and acquisition methods. J. Magn. Reson. Imaging 2015;41:233–241. © 2014 Wiley Periodicals, Inc.
Relationship of computed tomography perfusion and positron emission tomography to tumour progression in malignant glioma
Authors: Yeung Timothy P. C. , Yartsev Slav , Lee Ting‐Yim , Wong Eugene , He Wenqing , Fisher Barbara , VanderSpek Lauren L. , Macdonald David , Bauman Glenn
Published: January 2014

Introduction

This study aimed to explore the potential for computed tomography (CT) perfusion and 18‐Fluorodeoxyglucose positron emission tomography (FDG‐PET) in predicting sites of future progressive tumour on a voxel‐by‐voxel basis after radiotherapy and chemotherapy.

Methods

Ten patients underwent pre‐radiotherapy magnetic resonance (MR), FDG‐PET and CT perfusion near the end of radiotherapy and repeated post‐radiotherapy follow‐up MR scans. The relationships between these images and tumour progression were assessed using logistic regression. Cross‐validation with receiver operating characteristic (ROC) analysis was used to assess the value of these images in predicting sites of tumour progression.

Results

Pre‐radiotherapy MR‐defined gross tumour; near‐end‐of‐radiotherapy CT‐defined enhancing lesion; CT perfusion blood flow (BF), blood volume (BV) and permeability‐surface area (PS) product; FDG‐PET standard uptake value (SUV); and SUV:BF showed significant associations with tumour progression on follow‐up MR imaging (P < 0.0001). The mean sensitivity (±standard deviation), specificity and area under the ROC curve (AUC) of PS were 0.64 ± 0.15, 0.74 ± 0.07 and 0.72 ± 0.12 respectively. This mean AUC was higher than that of the pre‐radiotherapy MR‐defined gross tumour and near‐end‐of‐radiotherapy CT‐defined enhancing lesion (both AUCs = 0.6 ± 0.1, P ≤ 0.03). The multivariate model using BF, BV, PS and SUV had a mean AUC of 0.8 ± 0.1, but this was not significantly higher than the PS only model.

Conclusion

PS is the single best predictor of tumour progression when compared to other parameters, but voxel‐based prediction based on logistic regression had modest sensitivity and specificity.
An investigation of the effect of transient climate change on snowmelt, flood frequency and timing in northern Britain
Authors: Kay A. L. , Crooks S. M.
Published: January 2014

Climate change is almost certain to affect snow and ice processes. Even at lower latitudes, changes in snow cover at high altitudes can significantly affect catchment hydrology. This article uses data from a transient Regional Climate Model projection (HadRM3Q0) for 1950–2099 (A1B emissions) to drive hydrological models for three nested catchments on the river Dee in north‐east Scotland, to assess potential changes in flood frequency and timing using annual maxima and moving‐window analyses. Some results are also shown for an upland catchment in northern England. Modelling is performed both with and without a snow module, to demonstrate the effects of snowfall/melt and how these change through time and vary between catchments. Modelled changes in flood magnitude and timing are nonlinear, with most changes for daily mean flows not significant. For longer duration (30‐day) flows with snow there are significant decreases in peak magnitude, particularly for the smaller higher altitude Dee catchments, with peaks occurring months earlier in future (changes without snow are generally not significant). There is a general convergence in results with and without snow later in the period, as snow processes become less important, but convergence occurs at different times for different catchments and occurs differently for daily and 30‐day peak flows due to the differential effects of snow at different durations. This not only highlights the importance of including snow processes for such catchments, particularly for longer duration flows, but also highlights the complexity of interactions: Physical catchment properties, the balance between precipitation occurrence and temperature, and how this balance alters as the climate changes will each be critical in determining the impact on the magnitude and timing of peak flows, making it hard to generalize results.
Etiology of surgical site infections after primary total joint arthroplasties
Authors: Benito Natividad , Franco María , Coll Pere , Gálvez María Luz , Jordán Marcos , López‐Contreras Joaquín , Pomar Virginia , Monllau Joan Carles , Mirelis Beatriz , Gurguí Mercè
Published: January 2014

We sought to characterize the causative pathogens of surgical site infections (SSIs) following primary total joint arthroplasties and to evaluate trends in the microbial etiology. We analyzed the etiology of SSIs following 2,632 total hip arthroplasty and knee arthroplasty procedures performed at our institution from 2004 through 2010. We calculated the annual proportion of SSIs accounted for each of the most common organisms and evaluated trends using the χ2 test for trend. SSIs were identified in 111 procedures (4.2%). The annual incidence of SSIs did not change significantly during the study period. Staphylococci were the most common cause of infection (59.6%) and most of infections were monomicrobial (82.8%). From 2004 to 2010, the annual proportion of infections due to gram‐negative bacilli (GNB) increased from 21.4% to 66.7% (p = 0.085 for trend). This increase was accompanied by a decline in the proportion of SSIs from coagulase‐negative staphylococci (p = 0.003). Additionally, we found an increase in the percentage of polymicrobial infections (from 7.1% in 2004 to 41.7% in 2010, p = 0.014). Multivariate analysis corroborated these trends. Our study reports an emergence of GNB as a cause of SSIs after primary total joint arthroplaties and an increase of polymicrobial infections. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:633–637, 2014.
Bio protection and preservation of raw beef meat using pungent aromatic plant substances
Authors: Radha krishnan Kesavan , Babuskin Srinivasan , Babu Packirisamy Azhagu Saravana , Fayidh Mohammed Abbas , Sabina Kalleary , Archana Ganesan , Sivarajan Meenatchisundaram , Sukumar Muthusamy
Published: January 2014

BACKGROUND

This study examined the effectiveness of three individual spice (clove, cinnamon and oregano) extracts and their combinations in raw beef meat during refrigerated storage. Meat samples were monitored for microbiological (total viable count, Enterobacteriaceae, lactic acid bacteria, Brochothrix thermosphacta and Pseudomonas spp.) and physicochemical (pH, colour and thiobarbituric acid‐reactive substances (TBARS)) attributes.

RESULTS

Samples treated with the combination of all three spice extracts showed lower bacterial counts and better L*, a* and b* values among treated samples during the storage period. Positive and negative control samples had the highest TBARS values at the end of the storage period. With the addition of spice extracts, TBARS values in raw beef samples were retarded effectively (P < 0.05) compared with control samples, especially when the combination of all three spice extracts was used.

CONCLUSION

The results of this study show that spice extracts were effective in inhibiting the growth of microbial populations and retarding lipid oxidation during refrigerated storage (4 °C) of raw beef meat. They also suggest that combinations of these extracts may have potential as natural preservatives in raw meat products. © 2014 Society of Chemical Industry
Effect of pure microsteatosis on transplant outcomes after living donor liver transplantation: A matched case-control study
Authors: Han Sangbin , Ko Justin Sangwook , Kwon Gheeyoung , Park Cheolkeun , Lee Sanghoon , Kim Jongman , Kim Gaabsoo , Kwon Choonhyuck David , Gwak Misook , Ha Sangyun
Published: January 2014

Liver steatosis mostly exists in a mixed form of macrosteatosis (MaS) and microsteatosis (MiS). This coexistence is responsible for previous conflicting results regarding the importance of MiS in liver transplantation. We aimed to evaluate the independent effect of MiS on posttransplant outcomes with the exclusion of the confounding effect of MaS. Seventy-one living donors who had pure MiS (defined as an MiS degree > 5% without MaS) were matched 1:1 with control donors, and 66 recipients who received pure MiS grafts were matched 1:1 with control recipients on the basis of propensity scores. Matched variables included the donor age, remnant liver volume, cold ischemia time, graft-to-recipient weight ratio and Model for End-Stage Liver Disease score. The degree of pure MiS ranged from 5% to 50%. Donors in the control and pure MiS groups were comparable with respect to peak postoperative transaminase concentrations [alanine aminotransferase (ALT): 194 versus 176 IU/L, P = 0.61] and postoperative complications. Recipients in the control and pure MiS groups were comparable with respect to recipient (P = 0.15) and graft survival rates (P = 0.56) as well as peak postoperative transaminase concentrations (ALT: 266 versus 281 IU/L, P = 0.88), and graft regeneration rates at 2 weeks (61% versus 59%, P = 0.73). The 2 groups were also comparable with respect to major complications, primary graft dysfunction/nonfunction, intensive care unit/hospital stays, and metabolic diseases. In conclusion, MiS alone does not seem to impair the posttransplant outcomes of living donors and their recipients. The interaction between MiS and MaS, and the effect of a greater degree of MiS are the next important topics to be further evaluated in the mixed steatosis population. Liver Transpl 20:473–482, 2014. © 2014 AASLD.
Multiple‐Injection Method in High‐Temperature Two‐Dimensional Liquid Chromatography (2D HT‐LC)
Authors: Mekap Dibyaranjan , Macko Tibor , Brüll Robert , Cong Rongjuan , deGroot Willem , Parrott Albert , Yau Wallace
Published: January 2014

Comprehensively characterizing the relationship between the distributions with regard to chemical composition (CCD) and molar mass (MMD) of polyolefins is vital to establish structure–property relationships. Two‐dimensional high‐temperature liquid chromatography (2D HT‐LC), which couples a high‐temperature solvent gradient interactive chromatography (HT‐SGIC) step for compositional separation with a high‐temperature size exclusion chromatography (HT‐SEC) step for MMD determination in an on‐line manner is emerging as a tool of choice to satisfy this necessity. A serious problem commonly associated with multidimensional chromatography is the very low detector response (DR) due to the dilution in the HT‐SEC step. Using higher sample concentrations or larger sample loops cannot address this appropriately because injections may become irreproducible, or poorly shaped peaks may result due to concentration effects. This paper shows that stacked injections (repeatedly injecting a polymer sample and then starting the desorption step) is a unique way to overcome these difficulties. 2D HT‐LC analysis of blends of ethylene/1‐octene copolymers using stacked injections proves that the DR can be significantly enhanced without co‐elution of the blend components or overloading of the column.

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Structural Changes in Therapeutic RNAs
Authors: Tkachuk Z. Yu. , Kozlov A. V. , Skorobogatov O. Yu.
Published: January 2014

Therapeutic RNAs have been strongly influencing the pharmaceutical market, which has been marked by capturing its part in last decade. Wide range of biological activities, production easiness and relative cheapness result in a powerful background for its mass production and implication in pharmacology. Their structure is known to be directly linked to the conformation they posses at given conditions. Conformational changes that may occur in response to various factors are believed to cause serious functional activity changes.
Structure and Interaction of Poly(ethylene glycol) in Aqueous Solutions. Small‐Angle Neutron Scattering Data
Authors: Petrenko Viktor , Bulavin Leonid , Avdeev Mikhail , Garamus Vasil , Koneracka Martina , Kopcansky Peter
Published: January 2014

Behavior of low molecular mass poly(ethylene glycol) (PEG) polymer, i.e. molar masses Mn = 400 and 1000, in heavy water is studied by small‐angle neutron scattering (SANS). Some part of the polymer molecules in concentrated solutions is found to form aggregates with size exceeding 30 nm. The form‐factor of Gaussian coil is used to describe low concentrated PEG solutions. Virial coefficients are obtained from approximation of experimental SANS data for PEG solutions with concentration higher than 3% where the interparticle interaction effect is well observed.
Biopolymers and Biomacromolecules Solvent Dynamics
Authors: Rossi Claudio , Bonechi Claudia , Foletti Alberto , Magnani Agnese , Martini Silvia
Published: January 2014

Biomacromolecules in solution modify the structure and the dynamics of the bulk water at the solute‐solvent interface. The ordering effects of biomolecules, in particular proteins, are extended for several angstroms. The role of the hydration shells around a protein has yet to be completely understood. Hydrated proteins maintain more dynamic flexibility with respect to the dried system, which is an important property in protein‐protein and/or protein‐ligand recognition processes. In this paper we propose a method for analyzing the dynamical properties of the water molecules present in the hydration shells of proteins. The approach is based on analysis of the effects of protein‐solvent interactions on water protons NMR relaxation parameters. The water proton spin‐lattice relaxation rate in protein solution is analyzed considering all possible dipolar contributions from coupled protons environments. The analysis of both selective and non‐selective water spin‐lattice relaxation rates allowed the calculation of the average effective correlation time for the water molecules at the protein interface and the evaluation of the long range ordering effect of the protein surface.
Finite‐time control of impulsive hybrid dynamical systems in pest management
Authors: Zhang Hong , Georgescu Paul
Published: January 2014

This paper deals with the dynamics of a class of hybrid dynamical systems, which are subject to time‐dependent impulsive perturbations within a finite‐time interval and describe control strategies for integrated pest management. By using suitably defined Lyapunov functionals, sufficient conditions for the finite‐time contractive stability of the null solution are found by means of monotonicity arguments. Finally, a numerical simulation illustrates the theoretical analysis. Copyright © 2014 John Wiley & Sons, Ltd.
On the integrability of the (1+1)‐dimensional and (2+1)‐dimensional Ito equations
Authors: Wang Yun‐Hu
Published: January 2014

Under investigation in this paper are the (1+1)‐dimensional and (2+1)‐dimensional Ito equations. With the help of the Bell polynomials method, Hirota bilinear method and symbolic computation, the bilinear representations, N‐soliton solutions, bilinear Bäcklund transformations and Lax pairs of these two equations are obtained, respectively. In particular, we obtain a new bilinear form and N‐soliton solutions of the (2+1)‐dimensional Ito equation. The bilinear Bäcklund transformation and Lax pair of the (2+1)‐dimensional Ito equation are also obtained for the first time. Copyright © 2014 John Wiley & Sons, Ltd.
Some results on electromagnetic transmission eigenvalues
Authors: Zeng Fang , Turner Tiara , Sun Jiguang
Published: January 2014

The electromagnetic interior transmission problem is a boundary value problem, which is neither elliptic nor self‐adjoint. The associated transmission eigenvalue problem has important applications in the inverse electromagnetic scattering theory for inhomogeneous media. In this paper, we show that, in general, there do not exist purely imaginary electromagnetic transmission eigenvalues. For constant index of refraction, we prove that it is uniquely determined by the smallest (real) transmission eigenvalue. Finally, we show that complex transmission eigenvalues must lie in a certain region in the complex plane. The result is verified by examples. Copyright © 2014 John Wiley & Sons, Ltd.
Global stability of nonresident computer virus models
Authors: Muroya Yoshiaki , Kuniya Toshikazu
Published: January 2014

In this paper, applying Lyapunov functional techniques to nonresident computer virus models, we establish global dynamics of the model whose threshold parameter is the basic reproduction number R0 such that the virus‐free equilibrium is globally asymptotically stable when R0 ≤ 1, and the infected equilibrium is globally asymptotically stable when R0 > 1 under the same restricted condition on a parameter, which appeared in the literature on delayed susceptible‐infected‐recovered‐susceptible (SIRS) epidemic models. We use new techniques on permanence and global stability of this model for R0 > 1. Copyright © 2014 John Wiley & Sons, Ltd.
Existence of positive periodic solution of a hepatitis B virus infection model
Authors: Fang Haiquan , Wang Min , Zhou Tiejun
Published: January 2014

In this paper, a periodic model for hepatitis B virus infection is proposed. The model describes the breeding of the infected cells and the periodic variation of the environment. On the basis of the continuation theorem of coincidence degree theory, a condition for the existence of a positive periodic solution to the model is established. The result can be used to explain the wave phenomenon on the density of the pathogens in patients blood and the occurrence of superinfection in hepatitis B virus infections. Copyright © 2014 John Wiley & Sons, Ltd.
Metabolic effects of a high‐fat diet post‐weaning after low maternal dietary folate during pregnancy and lactation
Authors: McKay Jill A. , Xie Long , Manus Caroline , Langie Sabine A. S. , Maxwell Ross J. , Ford Dianne , Mathers John C.
Published: January 2014

Scope

Investigate the influence of low‐folate supply during pregnancy and lactation on obesity and markers of the metabolic syndrome in offspring, and how provision of a high‐fat diet post weaning may exacerbate the resultant phenotype.

Methods and results

Female C57Bl/6 mice were randomized to low or normal folate diets (0.4 or 2 mg folic acid/kg diet) prior to and during pregnancy and lactation. At 4 wk of age, offspring were randomized to high‐ or low‐fat diets, weighed weekly and food intake assessed at 9 and 18 wk old. Adiposity was measured at 3 and 6 months. Plasma glucose and triacylglycerol (TAG) concentrations were measured at 6 months.

Maternal folate supply did not influence adult offspring body weight or adiposity. High‐fat feeding post weaning increased body weight and adiposity at 3 and 6 months (p > 0.001). Maternal low folate lowered plasma glucose (p = 0.010) but increased plasma TAG (p = 0.048). High‐fat feeding post weaning increased plasma glucose and TAG (p = 0.023, p = 0.049 respectively). Offspring from folate‐depleted (but not folate‐adequate) dams had 30% higher TAG concentration when fed the high‐fat diet from weaning (p = 0.005 for interaction).

Conclusion

Inadequate maternal folate intake has long‐term effects on offspring metabolism, manifested as increased circulating TAG, particularly in offspring with high‐fat intake post weaning.
Reducing contrast contamination in radial turbo‐spin‐echo acquisitions by combining a narrow‐band KWIC filter with parallel imaging
Authors: Neumann Daniel , Breuer Felix A. , Völker Michael , Brandt Tobias , Griswold Mark A. , Jakob Peter M. , Blaimer Martin
Published: January 2014

Purpose

Cartesian turbo spin‐echo (TSE) and radial TSE images are usually reconstructed by assembling data containing different contrast information into a single k‐space. This approach results in mixed contrast contributions in the images, which may reduce their diagnostic value. The goal of this work is to improve the image contrast from radial TSE acquisitions by reducing the contribution of signals with undesired contrast information.

Methods

Radial TSE acquisitions allow the reconstruction of multiple images with different T2 contrasts using the k‐space weighted image contrast (KWIC) filter. In this work, the image contrast is improved by reducing the band‐width of the KWIC filter. Data for the reconstruction of a single image are selected from within a small temporal range around the desired echo time. The resulting dataset is undersampled and, therefore, an iterative parallel imaging algorithm is applied to remove aliasing artifacts.

Results

Radial TSE images of the human brain reconstructed with the proposed method show an improved contrast when compared with Cartesian TSE images or radial TSE images with conventional KWIC reconstructions.

Conclusion

The proposed method provides multi‐contrast images from radial TSE data with contrasts similar to multi spin‐echo images. Contaminations from unwanted contrast weightings are strongly reduced. Magn Reson Med 72:1680–1686, 2014. © 2014 Wiley Periodicals, Inc.
Accelerating sequences in the presence of metal by exploiting the spatial distribution of off‐resonance
Authors: Smith Matthew R. , Artz Nathan S. , Koch Kevin M. , Samsonov Alexey , Reeder Scott B.
Published: January 2014

Purpose

To demonstrate feasibility of exploiting the spatial distribution of off‐resonance surrounding metallic implants for accelerating multispectral imaging techniques.

Theory and Methods

Multispectral imaging (MSI) techniques perform time‐consuming independent three‐dimensional acquisitions with varying radio frequency offsets to address the extreme off‐resonance from metallic implants. Each off‐resonance bin provides a unique spatial sensitivity that is analogous to the sensitivity of a receiver coil and, therefore, provides a unique opportunity for acceleration. Fully sampled MSI was performed to demonstrate retrospective acceleration. A uniform sampling pattern across off‐resonance bins was compared with several adaptive sampling strategies using a total hip replacement phantom. Monte Carlo simulations were performed to compare noise propagation of two of these strategies. With a total knee replacement phantom, positive and negative off‐resonance bins were strategically sampled with respect to the B0 field to minimize aliasing. Reconstructions were performed with a parallel imaging framework to demonstrate retrospective acceleration.

Results

An adaptive sampling scheme dramatically improved reconstruction quality, which was supported by the noise propagation analysis. Independent acceleration of negative and positive off‐resonance bins demonstrated reduced overlapping of aliased signal to improve the reconstruction.

Conclusion

This work presents the feasibility of acceleration in the presence of metal by exploiting the spatial sensitivities of off‐resonance bins. Magn Reson Med 72:1658–1667, 2014. © 2014 Wiley Periodicals, Inc.
Frequency and phase drift correction of magnetic resonance spectroscopy data by spectral registration in the time domain
Authors: Near Jamie , Edden Richard , Evans C. John , Paquin Raphaël , Harris Ashley , Jezzard Peter
Published: January 2014

Purpose

Frequency and phase drifts are a common problem in the acquisition of in vivo magnetic resonance spectroscopy (MRS) data. If not accounted for, frequency and phase drifts will result in artifactual broadening of spectral peaks, distortion of spectral lineshapes, and a reduction in signal‐to‐noise ratio (SNR). We present herein a new method for estimating and correcting frequency and phase drifts in in vivo MRS data.

Methods

We used a simple method of fitting each spectral average to a reference scan (often the first average in the series) in the time domain through adjustment of frequency and phase terms. Due to the similarity with image registration, this method is referred to as “spectral registration.” Using simulated data with known frequency and phase drifts, the performance of spectral registration was compared with two existing methods at various SNR levels.

Results

Spectral registration performed well in comparison with the other methods tested in terms of both frequency and phase drift estimation.

Conclusions

Spectral registration provides an effective method for frequency and phase drift correction. It does not involve the collection of navigator echoes, and does not rely on any specific resonances, such as residual water or creatine, making it highly versatile. Magn Reson Med 73:44–50, 2015. © 2014 Wiley Periodicals, Inc.
Monitoring mammary tumor progression and effect of tamoxifen treatment in MMTV‐PymT using MRI and magnetic resonance spectroscopy with hyperpolarized [1‐13C]pyruvate
Authors: Asghar Butt Sadia , Søgaard Lise V. , Ardenkjaer‐Larsen Jan H. , Lauritzen Mette H. , Engelholm Lars H. , Paulson Olaf B. , Mirza Osman , Holck Susanne , Magnusson Peter , Åkeson Per
Published: January 2014

Purpose

To use dynamic magnetic resonance spectroscopy (MRS) of hyperpolarized 13C‐pyruvate to follow the progress over time in vivo of breast cancer metabolism in the MMTV‐PymT model, and to follow the response to the anti‐estrogen drug tamoxifen.

Methods

Tumor growth was monitored by anatomical MRI by measuring tumor volumes. Dynamic MRS of hyperpolarized 13C was used to measure an “apparent” pyruvate‐to‐lactate rate constant (kp) of lactate dehydrogenase (LDH) in vivo. Further, ex vivo pathology and in vitro LDH initial reaction velocity were evaluated.

Results

Tamoxifen significantly halted the tumor growth measured as tumor volume by MRI. In the untreated animals, kp correlated with tumor growth. The kP was somewhat but not significantly lower in the treated group. Studies in vitro confirmed the effects of tamoxifen on tumor growth, and here the LDH reaction velocity was reduced significantly in the treated group.

Conclusion

These hyperpolarized 13C MRS findings indicate that tumor metabolic changes affects kP. The measured kp did not relate to treatment response to the same extent as did tumor growth, histological evaluation, and in vitro determination of LDH activity. Magn Reson Med 73:51–58, 2015. © 2014 Wiley Periodicals, Inc.
Accelerated whole‐heart coronary MRA using motion‐corrected sensitivity encoding with three‐dimensional projection reconstruction
Authors: Pang Jianing , Sharif Behzad , Arsanjani Reza , Bi Xiaoming , Fan Zhaoyang , Yang Qi , Li Kuncheng , Berman Daniel S. , Li Debiao
Published: January 2014

Purpose

To achieve whole‐heart coronary magnetic resonance angiography (MRA) with (1.0 mm)3 spatial resolution and 5 min of free‐breathing scan time.

Methods

We used an electrocardiograph‐gated, T2‐prepared and fat‐saturated balanced steady state free precession sequence with 3DPR trajectory for free‐breathing data acquisition with 100% gating efficiency. For image reconstruction, we used a self‐calibrating iterative SENSE scheme with integrated retrospective motion correction. We performed healthy volunteer study to compare the proposed method with motion‐corrected gridding at different retrospective undersampling levels on apparent signal‐to‐noise ratio (aSNR) and subjective coronary artery (CA) visualization scores.

Results

Compared with gridding, the proposed method significantly improved both image quality metrics for undersampled datasets with 6000, 8000, and 10,000 projections. With as few as 10,000 projections, the proposed method yielded good CA visualization scores (3.02 of 4) and aSNR values comparable to those with 20,000 projections.

Conclusion

Using the proposed method, good image quality was observed for free breathing whole‐heart coronary MRA at (1.0 mm)3 resolution with an achievable scan time of 5 min. Magn Reson Med 73:284–291, 2015. © 2014 Wiley Periodicals, Inc.
Banding artifact removal for bSSFP imaging with an elliptical signal model
Authors: Xiang Qing‐San , Hoff Michael N.
Published: January 2014

Purpose

Balanced steady‐state free precession (bSSFP) imaging has broad clinical applications by virtue of its high time efficiency and desirable contrast. Unfortunately, banding artifact is often seen as a result of signal modulation due to B0 inhomogeneity. This study aims to develop an effective method for banding artifact suppression.

Methods

bSSFP is analyzed with an elliptical signal model. A simple analytical “Geometric‐Solution” (GS) is presented to demodulate the signal from B0 inhomogeneity dependence with phase‐cycled bSSFP data from both a computer simulation and experiments using phantom and human subjects.

Results

The proposed algorithm is able to remove banding artifacts completely. It also compares favorably with the complex sum (CS), which is considered one of the more efficient methods for banding artifact correction.

Conclusion

Using an elliptical signal model, an analytical solution to the bSSFP banding problem has been found and demonstrated with simulation as well as phantom and in vivo experiments. Magn Reson Med 71:927–933, 2014. © 2014 Wiley Periodicals, Inc.
Impact of capped and uncapped abandoned leads on the heating of an MR‐conditional pacemaker implant
Authors: Mattei Eugenio , Gentili Giulia , Censi Federica , Triventi Michele , Calcagnini Giovanni
Published: January 2014

Purpose

To assess the risk of radiofrequency (RF) ‐induced heating in patients with MR‐conditional pacemaker (PM) systems, in the presence of another lead abandoned from a previous implant.

Methods

Four commercial pacemaker leads were placed beside a MR‐conditional PM system, inside a human trunk simulator. The phantom has been exposed to the RF generated by a 64 MHz body bird‐cage coil (whole‐body specific absorption rate [SAR] = 1 W/kg) and the induced heating was measured at the tip of the abandoned lead and of the MR‐conditional implant. Configurations that maximize the coupling between the RF field and the leads have been tested, as well as realistic implant positions.

Results

Abandoned leads showed heating behaviors that strongly depend on the termination condition (abandoned‐capped or saline exposed) and on the lead path (left or right positioning). Given a whole‐body SAR = 1 W/kg, a maximum temperature rise of 17.6°C was observed. The presence of the abandoned lead modifies the RF‐heating profile of the MR‐conditional implant: either an increase or a decrease in the induced heating at its lead tip can occur, mainly depending on the relative position of the two leads. Variations ranging from −63% to +69% with respect to the MR‐conditional system alone were observed.

Conclusion

These findings provide experimental evidence that the presence of an abandoned lead poses an additional risk for the patient implanted with a MR‐conditional PM system. Our results support the current PM manufacturers' policy of conditioning the MR compatibility of their systems to the absence of abandoned leads (including leads from MR‐conditional implants). From a clinical point of view, in such cases, the decision whether to perform the exam shall be based upon a risk/benefit evaluation, as in the case of conventional PM systems. Magn Reson Med 73:390–400, 2015. © 2014 Wiley Periodicals, Inc.
Combining Odontochronology, Tooth Wear Assessment, and Linear Enamel Hypoplasia (LEH) Recording to Assess Pig Domestication in Neolithic Henan, China
Authors: Pike‐Tay A. , Ma X. , Hou Y. , Liang F. , Lin M. , Peterson V.
Published: January 2014

Mandibles of Sus scrofa (wild boar/pig) from ritual pits H160 and H208 of Longshangang, a Late Yangshao Neolithic site in Xichuan County, Henan, were analyzed for evidence of domestication. Three methods of dental analysis were applied: odontochronology, tooth wear assessment, and linear enamel hypoplasia (LEH) recording, which provide age at death, season of kill, and season of birth data. We investigate whether: (i) the LEH height frequencies on the second molars of the mandibles correspond with the possibility of double farrowing and (2) double farrowing is supported by the season of and age at slaughter data. If so, these data suggest a substantial degree of human management of suids at the site. Copyright © 2014 John Wiley & Sons, Ltd.
A novel mutation of ABCG5 gene in a Turkish boy with phytosterolemia presenting with macrotrombocytopenia and stomatocytosis
Authors: Kaya Zühre , Niu Dau‐Ming , Yorulmaz Aslı , Tekin Aziz , Gürsel Türkiz
Published: January 2014

Phytosterolemia is a rare autosomal recessive sterol storage disease caused by mutations in ABCG5 and ABCG8 genes. A 9‐year‐old Turkish boy who was presented with exclusively hematologic abnormalities had elevated plant sterol levels. Sequencing of ABCG5 and ABCG8 genes revealed a novel homozygous IVS10‐1 G>T mutation in ABCG5 gene. Four of the 13 family members had xanthoma but they had neither hematologic abnormalities nor IVS10‐1 G>T mutation. Ezetimibe therapy reduced plant sterol levels in association with marked clinical improvement. Plant sterol levels and ABCG5/ABCG8 genes should be analysed in patients with unexplained hemolytic anemia and macrothrombocytopenia. Pediatr Blood Cancer 2014; 61:1457–1459. © 2014 Wiley Periodicals, Inc.
Survival from teenage and young adult cancer in Northern England, 1968–2008
Authors: Basta N.O. , James P.W. , Gomez‐Pozo B. , Craft A.W. , Norman P. , McNally R.J.Q.
Published: January 2014

Background

Although cancer is relatively rare in teenagers and young adults (TYAs) aged 15–24 years, it is a major cause of death in this age group. This study investigated survival trends in TYA cancer diagnosed in Northern England, 1968–2008.

Methods

Five‐year survival was analyzed using Kaplan–Meier estimation for four successive time periods. Cox regression analysis was used to investigate associations with demographic factors.

Results

The study included 2,987 cases (1,634 males, 1,353 females). Five‐year survival for all patients with cancer improved greatly from 46% in 1968–1977 to 84% in 1998–2008 (P < 0.001), for patients with leukemia from 2% to 71% (P < 0.001), lymphoma from 66% to 86% (P < 0.001), central nervous system tumors from 53% to 84% (P < 0.001), bone tumors from 29% to 72% (P < 0.001), germ cell tumors from 39% to 94% (P < 0.001), melanoma and skin cancer from 64% to 100% (P < 0.001), and carcinomas from 48% to 80% (P < 0.001). Cox analysis showed that for all patients with cancer, survival was better for females than males (HR = 0.83; 95% CI 0.74–0.94,P < 0.001), for patients aged 20–24 years compared with those aged 15–19 years (HR = 0.84; 95% CI 0.75–0.94,P = 0.002), but survival was worse for patients who resided in more deprived areas (HR = 1.06; 95% CI 1.01–1.11,P = 0.025).

Conclusion

There have been large improvements in TYA cancer survival in Northern England over the last four decades. Future work should determine factors that could lead to even better survival, including possible links with delayed diagnosis. Pediatr Blood Cancer 2014;61:901–906. © 2014 Wiley Periodicals, Inc.