bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of planning‐free vessel‐encoded pseudo‐continuous arterial spin labeling MR imaging as territorial‐ASL strategy by comparison to super‐selective p‐CASL MRI
Authors: Hartkamp Nolan S. , Helle Michael , Chappell Michael A. , Okell Thomas W. , Hendrikse Jeroen , Bokkers Reinoud P. H. , van Osch Matthias J. P.
Published: July 2013

Purpose

Vessel‐encoded (VE) pseudo‐continuous arterial spin labeling (p‐CASL) is a territorial ASL (T‐ASL) technique to identify the perfusion territories of cerebral arteries. The aim of this study was to validate the output of three Vessel‐encoded p‐CASL image processing methods, k‐means clustering with and without subsequent linear analysis and a Bayesian framework, by comparison with the perfusion maps acquired with super‐selective p‐CASL.

Methods

The comparison was done quantitatively using the Hausdorff distance and Dice similarity coefficient in the territories of the right and left internal carotid arteries, the basilar artery, and the right and left vertebral arteries. A qualitative comparison was done in the areas of the anterior and posterior circulation, and the deep gray matter.

Results

The overall agreement between the Vessel‐encoded p‐CASL image processing methods and super‐selective p‐CASL was good; with the difference that the linear analysis and the Bayesian framework were able to detect mixed perfusion.

Conclusion

Planning‐free Vessel‐encoded p‐CASL with k‐means clustering appears suitable as a general purpose T‐ASL strategy, but to determine mixed perfusion a combination with linear analysis, or the Bayesian framework is preferable, which are superior in this regard. To accurately determine the perfusion territory of a single vessel, super‐selective p‐CASL is still recommended. Magn Reson Med 71:2059–2070, 2014. © 2013 Wiley Periodicals, Inc.
Dynamic contrast enhanced MRI parameters and tumor cellularity in a rat model of cerebral glioma at 7 T
Authors: Aryal Madhava P. , Nagaraja Tavarekere N. , Keenan Kelly A. , Bagher‐Ebadian Hassan , Panda Swayamprava , Brown Stephen L. , Cabral Glauber , Fenstermacher Joseph D. , Ewing James R.
Published: July 2013

Purpose

To test the hypothesis that a noninvasive dynamic contrast enhanced MRI (DCE‐MRI) derived interstitial volume fraction (ve) and/or distribution volume (VD) were correlated with tumor cellularity in cerebral tumor.

Methods

T1‐weighted DCE‐MRI studies were performed in 18 athymic rats implanted with U251 xenografts. After DCE‐MRI, sectioned brain tissues were stained with Hematoxylin and Eosin for cell counting. Using a Standard Model analysis and Logan graphical plot, DCE‐MRI image sets during and after the injection of a gadolinium contrast agent were used to estimate the parameters plasma volume (vp), forward transfer constant (Ktrans), ve, and VD.

Results

Parameter values in regions where the standard model was selected as the best model were: (mean ± S.D.): vp = (0.81 ± 0.40)%, Ktrans = (2.09 ± 0.65) × 10−2 min−1, ve = (6.65 ± 1.86)%, and VD = (7.21 ± 1.98)%. The Logan‐estimated VD was strongly correlated with the standard model's vp + ve (r = 0.91, P < 0.001). The parameters, ve and/or VD, were significantly correlated with tumor cellularity (r ≥ −0.75, P < 0.001 for both).

Conclusion

These data suggest that tumor cellularity can be estimated noninvasively by DCE‐MRI, thus supporting its utility in assessing tumor pathophysiology. Magn Reson Med 71:2206–2214, 2014. © 2013 Wiley Periodicals, Inc.
Accurate T1 mapping for oxygen‐enhanced MRI in the mouse lung using a segmented inversion‐recovery ultrashort echo‐time sequence
Authors: Zurek M. , Johansson E. , Risse F. , Alamidi D. , Olsson L. E. , Hockings P. D.
Published: July 2013

Purpose

A segmented inversion‐recovery module combined with the 2D ultrashort echo time radial technique is proposed that allows accurate pixel level T1 mapping of mouse lung in vivo.

Methods

Numerical simulations were performed to estimate T1 measurement accuracy and precision versus flip angle and signal‐to‐noise ratio. Phantom measurements were used for protocol validation, where the segmented inversion‐recovery ultrashort echo‐time sequence was compared with the reference technique (inversion‐recovery rapid acquisition with refocused echoes). The in vivo experiments were carried out on free‐breathing C57 mice (n = 10), breathing first air and then oxygen.

Results

The simulations demonstrated the high potential of the technique for accurate and precise T1 assessment. Phantom experiments showed good agreement for T1 values measured with segmented inversion‐recovery ultrashort echo‐time and the reference technique. The in vivo experiment demonstrated the utility of the technique in oxygen‐enhanced assessment, where small T1 changes were detected with high precision.

Conclusion

Segmented inversion‐recovery ultrashort echo‐time provides accurate, high resolution T1 mapping of the lung parenchyma. Magn Reson Med 71:2180–2185, 2014. © 2013 Wiley Periodicals, Inc.
Whole brain perfusion measurements using arterial spin labeling with multiband acquisition
Authors: Kim Tae , Shin Wanyong , Zhao Tiejun , Beall Erik B. , Lowe Mark J. , Bae Kyongtae T.
Published: July 2013

Purpose

The multiband (MB) excitation and reconstruction technique was both developed and evaluated for accelerated data acquisition of arterial spin labeling (ASL) to cover whole brain perfusion maps.

Theory and Methods

MB excitation was incorporated into a pulsed ASL (PASL) technique and compared with conventional single‐band excitation PASL from healthy subjects, using a 32‐channel head receiver coil at 3 T. The MB de‐aliasing performance and effectiveness in perfusion measurement were measured with varying MB acceleration factors and gaps between MB excitations.

Results

The MB PASL perfusion maps were in good agreement with the conventional single‐band PASL maps at matched slices. The imaging coverage could be effectively extended with the MB technique by a factor up to 5. A gap as small as 3 cm between MB excitations resulted in a comparable ASL signal loss and temporal‐signal‐to‐noise ratio with single‐band PASL.

Conclusion

The MB ASL technique is an effective method to evaluate whole brain perfusion because it minimizes the temporal spread of labeled spins across slices, resulting in more accurate perfusion measurements. Magn Reson Med 70:1653–1661, 2013. © 2013 Wiley Periodicals, Inc.
Three‐dimensional heart locator for whole‐heart coronary magnetic resonance angiography
Authors: Moghari Mehdi H. , Roujol Sébastien , Henningsson Markus , Kissinger Kraig V. , Annese David , Nezafat Reza , Manning Warren J. , Geva Tal , Powell Andrew J.
Published: July 2013

Purpose

Coronary magnetic resonance angiography (MRA) is commonly performed with diaphragmatic navigator (NAV) gating to compensate for respiratory motion, but this approach is inefficient as data must be reacquired when it is outside the acceptance window. We therefore developed and validated a motion compensation technique based on three‐dimensional (3D) spatial registration in which data are accepted throughout the respiratory cycle.

Methods

A novel respiratory motion compensation method was implemented that acquires a low‐resolution 3D‐image of the heart (3D‐LOC) just prior to coronary MRA data acquisition. 3D‐LOC volumes were registered to the first 3D‐LOC to estimate the respiratory‐induced heart motion and to modify the coronary MRA data and reconstruct motion‐corrected images. Whole‐heart coronary MRA datasets were acquired from nine healthy subjects using a diaphragmatic NAV and using 3D‐LOC.

Results

There was no significant difference between the subjective image score of NAV and 3D‐LOC in three main coronary branches. The vessel sharpness of 3D‐LOC was higher than NAV in the right (0.44 ± 0.08 vs. 0.49 ± 0.08; P = 0.055) and left circumflex arteries (0.49 ± 0.05 vs. 0.52 ± 0.04; P = 0.039). Scan time for 3D‐LOC was significantly shorter than NAV (4.3 ± 0.6 vs. 8.3 ± 2.3 min; P = 0.004).

Conclusion

Compared to NAV gating, 3D‐LOC for coronary MRA reduces scan time by nearly 50% without compromising image quality. Magn Reson Med 71:2118–2126, 2014. © 2013 Wiley Periodicals, Inc.
SPEED: SPectral Elements in Elastodynamics with Discontinuous Galerkin: a non‐conforming approach for 3D multi‐scale problems
Authors: Mazzieri I. , Stupazzini M. , Guidotti R. , Smerzini C.
Published: July 2013

This work presents a new high performance open‐source numerical code, namely SPectral Elements in Elastodynamics with Discontinuous Galerkin, to approach seismic wave propagation analysis in visco‐elastic heterogeneous three‐dimensional media on both local and regional scale. Based on non‐conforming high‐order techniques, such as the discontinuous Galerkin spectral approximation, along with efficient and scalable algorithms, the code allows one to deal with a non‐uniform polynomial degree distribution as well as a locally varying mesh size. Validation benchmarks are illustrated to check the accuracy, stability, and performance features of the parallel kernel, whereas illustrative examples are discussed to highlight the engineering applications of the method. The proposed method turns out to be particularly useful for a variety of earthquake engineering problems, such as modeling of dynamic soil structure and site‐city interaction effects, where accounting for multiscale wave propagation phenomena as well as sharp discontinuities in mechanical properties of the media is crucial. Copyright © 2013 John Wiley & Sons, Ltd.
Port reduction in parametrized component static condensation: approximation and a posteriori error estimation
Authors: Eftang Jens L. , Patera Anthony T.
Published: July 2013

We introduce a port (interface) approximation and a posteriori error bound framework for a general component‐based static condensation method in the context of parameter‐dependent linear elliptic partial differential equations. The key ingredients are as follows: (i) efficient empirical port approximation spaces—the dimensions of these spaces may be chosen small to reduce the computational cost associated with formation and solution of the static condensation system; and (ii) a computationally tractable a posteriori error bound realized through a non‐conforming approximation and associated conditioner—the error in the global system approximation, or in a scalar output quantity, may be bounded relatively sharply with respect to the underlying finite element discretization.

Our approximation and a posteriori error bound framework is of particular computational relevance for the static condensation reduced basis element (SCRBE) method. We provide several numerical examples within the SCRBE context, which serve to demonstrate the convergence rate of our port approximation procedure as well as the efficacy of our port reduction error bounds. Copyright © 2013 John Wiley & Sons, Ltd.
Coupling finite element and reliability analysis through proper generalized decomposition model reduction
Authors: Gallimard L. , Vidal P. , Polit O.
Published: July 2013

The FEM is the main tool used for structural analysis. When the design of the mechanical system involves uncertain parameters, a coupling of the FEM with reliability analysis algorithms allows to compute the failure probability of the system. However, this coupling leads to successive finite element analysis of parametric models involving high computational effort. Over the past years, model reduction techniques have been developed in order to reduce the computational requirements in the numerical simulation of complex models. The objective of this work is to propose an efficient methodology to compute the failure probability for a multi‐material elastic structure, where the Young moduli are considered as uncertain variables. A proper generalized decomposition algorithm is developed to compute the solution of parametric multi‐material model. This parametrized solution is used in conjunction with a first‐order reliability method to compute the failure probability of the structure. Applications to multilayered structures in two‐dimensional plane elasticity are presented.Copyright © 2013 John Wiley & Sons, Ltd.
Coupling of polynomial approximations with application to a boundary meshless method
Authors: Tampango Yendoubouam , Potier‐Ferry Michel , Koutsawa Yao , Tiem Sonnou
Published: July 2013

New bridging techniques are introduced to match high degree polynomials. This permits piecewise resolutions of elliptic partial differential equations (PDEs) in the framework of a boundary meshless method introduced recently. This new meshless method relies on the computation of Taylor series approximations deduced from the PDE, the shape functions being high degree polynomials. In this way, the PDE is solved quasi‐exactly inside the subdomains so that only discretization of the boundary and the interfaces are needed, which leads to small size matricial problems. The bridging techniques are based on the introduction of Lagrange multipliers and a set of collocation points on the boundary and the interfaces. Several numerical applications establish that the method is robust and permits an exponential convergence with the degree. Copyright © 2013 John Wiley & Sons, Ltd.
2,α‐norm optimal model reduction for optimal control problems subject to parabolic and hyperbolic evolution equations
Authors: Vossen G.
Published: July 2013

This paper deals with a numerical solution method for optimal control problems subject to parabolic and hyperbolic evolution equations. Firstly, the problem is semi‐discretized in space with the boundary or distributed controls as input and those parts of the discretized state appearing in the cost functional as output variables. The corresponding transfer function is then approximated optimally with respect to the 2,α‐norm providing an optimally reduced optimal control problem, which is finally solved by a first‐discretize‐then‐optimize approach. To enable the application of this reduction method, a new constrained optimal model reduction problem subject to reduced systems with real system matrices is considered. Necessary optimality conditions and a transformation procedure for the reduced system to a canonical form of real matrices are presented. The method is illustrated with numerical examples where also complicated controls with many bang‐bang arcs are investigated. The approximation quality of the optimal control and its correlation to the decay rate of the Hankel singular values of the system are numerically studied. A comparison to the approach of using Balanced Truncation for model reduction is applied. Copyright © 2013 John Wiley & Sons, Ltd.
Routine screening for suicidal intention in patients with cancer
Authors: Leung Yvonne W. , Li Madeline , Devins Gerald , Zimmermann Camilla , Rydall Anne , Lo Chris , Rodin Gary
Published: July 2013

Objectives

Suicide rates are elevated in individuals with cancer, although suicidal intention is not typically assessed in cancer centers. We evaluated in a large comprehensive cancer center the utility of an electronic Distress Assessment and Response Tool (DART), in which suicidal intention is assessed with a single item.

Methods

Patients attending cancer clinics completed DART as part of routine care. DART includes measures of physical symptoms, depression, anxiety, social difficulties, and practical concerns. Medical variables were obtained from the Princess Margaret Cancer Registry, the data warehouse of cancer patient statistics. A Generalized Estimating Equation (GEE) model was used to assess factors associated with suicidal intention.

Results

Between September 2009 and March 2012, 4822/5461 patients (88.3%) who completed DART consented to the use of their data for research. Amongst the latter, 280 (5.9%) of the 4775 patients who answered the question reported suicidal ideation, which was related to physical and psychological distress, and social difficulties (ps < 0.0001). Amongst those with ideation who responded to the intention question, 20/186 (10.8%) reported suicidal intention. Of respondents with more severe suicidal ideation, 12/49 (24.5%) reported suicidal intention. Using a GEE model, suicidal intention in those with ideation was significantly associated with male sex, difficulty making treatment decisions, and with everyday living concerns.

Conclusions

Suicidal ideation is reported on an electronic distress screening tool (DART) by almost 6% of cancer patients, of whom almost 11% report suicidal intention and 33% decline to indicate intention. DART demonstrated utility in identifying patients who may be at highest risk of completed suicide and who require urgent clinical assessment. Copyright © 2013 John Wiley & Sons, Ltd.
Psychosocial benefits of a novel mindfulness intervention versus standard support in distressed women with breast cancer
Authors: Monti Daniel A. , Kash Kathryn M. , Kunkel Elisabeth J. , Moss Aleeze , Mathews Michael , Brainard George , Anne Ranni , Leiby Benjamin E. , Pequinot Edward , Newberg Andrew B.
Published: July 2013

Objective

It is well documented that stress is associated with negative health outcomes in cancer patients. The purpose of this study was to assess the effects of a novel mindfulness intervention called mindfulness‐based art therapy (MBAT) versus standard educational support, on indices of stress and quality of life in breast cancer patients with high stress levels.

Methods

A total of 191 women were enrolled, stratified by age and stress level, and randomized to receive either an 8‐week MBAT intervention or a breast cancer educational support program of equal time and duration. Psychosocial stress was measured using the Symptoms Checklist‐90‐Revised, and quality of life was measured using the Medical Outcomes Study Short‐Form Health Survey at baseline, immediately post‐intervention, and at 6 months.

Results

Results showed overall significant improvements in psychosocial stress and quality of life in both the MBAT and educational support groups immediately post‐intervention; however, participants with high stress levels at baseline had significantly improved overall outcomes only in the MBAT group, both immediately post‐intervention and at 6 months. In addition, at 6 months follow‐up, participants attending five or more sessions trended toward retaining treatment effects better in the MBAT than in the control group. Finally, black women and white women were similar in terms of how they benefited from the MBAT intervention, even though white participants tended to have higher educational level and marital status.

Conclusions

In conclusion, MBAT is associated with significant, sustained benefits across a diverse range of breast cancer patients, particularly those with high stress levels. Copyright © 2013 John Wiley & Sons, Ltd.
Novel cytotoxic exhibition mode of antimicrobial peptide anoplin in MEL cells, the cell line of murine Friend leukemia virus‐induced leukemic cells
Authors: Zhu Li‐Na , Fu Cai‐Yun , Zhang Shi‐Fu , Chen Wei , Jin Yuan‐Ting , Zhao Fu‐Kun
Published: July 2013

Anoplin is a recently discovered antimicrobial peptide (AMP) isolated from the venom sac of the spider wasp Anoplius samariensis, and it is one of the shortest α‐helical AMP found naturally to date consisting of only ten amino acids. Previous results showed that anoplin exhibits potent antimicrobial activity but little hemolytic activity. In this study, we synthesized anoplin, studied its cytotoxicity in Friend virus‐induced leukemia cells [murine erythroleukemia (MEL) cells], and proposed its possible mechanism. Our results showed that anoplin could inhibit the proliferation of MEL cells in a dose‐dependent and time‐dependent manner via disrupting the integrity of cell membrane, which indicated that anoplin exerts its cytotoxicity efficacy. In addition, the cell cycle distribution of MEL cells was arrested in the G0/G1 phase significantly. However, anoplin could not induce obvious apoptosis in MEL cells, as well as anoplin could not induce visible changes on morphology and quantity in the bone marrow cells isolated from normal mice. All of these results indicate that anoplin, as generally believed, is a selective AMP, a value characteristic in the design of safe therapeutic agents. The cytotoxicity of anoplin on MEL cells was mainly attributable to the plasma membrane perturbation and also to the intracellular events such as the arrest of cell cycle. Although this is an initial study that explored the activity of anoplin in vitro rather than in vivo, with the increasing resistance of conventional chemotherapy, there is no doubt that anoplin has desirable feature to be developed as a novel and selective anticancer agent. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
k32‐type low‐frequency bimorph with giant electromechanical coupling factor
Authors: Liu Gang , Lei Shiming , Jiang Wenhua , Zhu Jiaqi , Cao Wenwu
Published: July 2013

Piezoelectric bimorph based on k32 mode of ternary 0.24Pb(In1/2Nb1/2)O3–0.46Pb(Mg1/3Nb2/3)O3–0.30PbTiO3 (0.24PIN–‐0.46PMN–‐0.30PT) single crystal poled along [011]c has been fabricated and tested. The bimorph features very large electromechanical coupling factor (0.80) and very low working frequency (less than half of PZT based bimorph for the same dimensions) owing to the super large lateral extensional piezoelectric constant d32 and large elastic compliances of the crystal. The bimorph design can be used for miniaturized low‐frequency electromechanical sensors and actuators.
Fabrication of silicon nanostructures using metal‐assisted etching in NaBF4
Authors: Nguyen Nhung T. P. , Coffinier Yannick , Thomy Vincent , Boukherroub Rabah
Published: July 2013

In this report, we demonstrate that sodium tetrafluoroborate (NaBF4) and silver nitrate (AgNO3) aqueous solution can be successfully used as wet etchant to produce silicon nanostructured layers with anti‐reflective properties. The morphology of the resulting nanostructures was studied as a function of various etching parameters, including reactant concentrations, temperature, time, substrate orientation, and doping level. The resulting nanostructures have been characterized using scanning electron microscopy (SEM) and reflectivity measurements.
Si substrate preparation for the VS and VLS growth of InAs nanowires
Authors: Rieger Torsten , Grützmacher Detlev , Lepsa Mihail Ion
Published: July 2013

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The growth of self‐catalyzed InAs nanowires on Si(111) substrates via vapour–solid (VS) and vapour–liquid–solid (VLS) growth mechanisms is investigated using molecular beam epitaxy. For both mechanisms, the substrate preparation plays a crucial role. In this context, the required thin oxide layer for the VS growth of the nanowires is obtained by treating the HF‐cleaned Si substrate with hydrogen peroxide. For the VLS growth, Ga is predeposited on the unprocessed Si substrate. The Ga forms droplets, which etch the native oxide and create the necessary pinholes.

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(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon nanowires – a versatile technology platform
Authors: Mikolajick Thomas , Heinzig André , Trommer Jens , Pregl Sebastian , Grube Matthias , Cuniberti Gianaurelio , Weber Walter M.
Published: July 2013

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Silicon nanowires offer unique properties like inherent small diameters, quasi‐one‐dimensional current transport and the flexibility to combine materials that cannot be combined in bulk or thin film structures. Based on these properties electron devices, sensors as well as solar cells and lithium batteries can be envisioned that significantly outperform their thin film or bulk counterparts. The possibility to form silicon nanowires in a top–down process using bulk silicon or silicon‐on‐insulator substrates, gives this technology the potential for a seamless integration into integrated electronic systems. This Review gives an overview of important device applications of silicon nanowires. Starting with nanowire fabrication, the different device concepts will be introduced and their most important features are reported.

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Illustration of silicon nanowire formation and application in a reconfigurable device.

(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Shewhart‐type Control Scheme to Monitor Weibull Data without Subgrouping
Authors: Chen Jung‐Tai
Published: July 2013

This study proposes a Shewhart control scheme to simultaneously monitor the shape parameter and the scale parameter of Weibull data without subgrouping. The proposed control scheme comprises two charts: the X chart and the moving‐ratio (MRa) chart. The X chart plots individual observations to detect the shift of the scale parameter by assuming that the shape parameter is in‐control. In contrast, the MRa chart plots moving ratios, the minimum of two consecutive Weibull data divided by the maximum of them, to detect the shift of the shape parameter. This study models the transition process of the proposed control scheme as a Markov chain to calculate two performance measures: the average number of observations to signal and the average run length. Performance analysis shows that the proposed control scheme is effective in detecting the shift of parameters, especially for the downward shift of the shape parameter. Finally, the implementation of the proposed control scheme is illustrated in two skewed data sets. Copyright © 2013 John Wiley & Sons, Ltd.
Set membership inversion and robust control from data of nonlinear systems
Authors: Novara C. , Canale M. , Milanese M. , Signorile M. C.
Published: July 2013

A set membership method for right inversion of nonlinear systems from data is proposed in the paper. Both the cases where the system to invert is known or unknown and therefore identified from data are addressed. The method does not require the invertibility of the regression function describing the system and ensures tight bounds on the inversion error. In the case of unknown system, the method allows the derivation of a robust right‐inverse, guaranteeing the inversion error bound for all the systems belonging to the uncertainty set which can be defined from the available prior and experimental information. Based on such a set membership inversion, two methods for robust control of nonlinear systems from data are introduced: nonlinear feed‐forward control (NFFC) and nonlinear internal model control (NIMC). Both the design methods ensure robust stability and bounded tracking errors for all the systems belonging to the involved uncertainty set. Two applicative examples of robust control from data are presented: NFFC control of semi‐active suspension systems and NIMC control of vehicle lateral dynamics.Copyright © 2013 John Wiley & Sons, Ltd.
Optimization of the straightness measurements on rough surfaces by Monte Carlo simulation
Authors: Hennebelle F. , Coorevits T. , Bigerelle M.
Published: July 2013

The straightness error of a coordinate measuring machine (CMM) is determined by measuring a rule standard. Thanks to a reversal technique, the straightness uncertainty of the CMM is theoretically dissociated from the straightness uncertainty of the rule. However, stochastic variations of the whole measurement system involve uncertainties of the CMM straightness error. To quantify these uncertainties, different sources of stochastic variations are listed with their associated probability density functions. Then Monte Carlo methods are performed first to quantify error and secondly to optimize measurement protocol. It is shown that a 5‐measurement distance from 0.1 mm to each measurement coordinate allows a double reduction of uncertainties, principally due to the rule roughness amplitude (Ra = 0.35 µm) and because this optimal distance of 0.1 mm is equal to the autocorrelation length of the rule roughness. With this optimal configuration, the final uncertainly on the straightness error of the CMM studied is less than 1 µm on the whole evaluated length of the rule (1 m). An algorithm, including Probe Tip Radius of the CMM and surface roughness of the piece, is finally proposed to increase CMM reliability by minimizing error measurements due to surface roughness of the measured piece. SCANNING 36:161–169, 2014. © 2013 Wiley Periodicals, Inc.
Non‐ignorable loss to follow‐up: correcting mortality estimates based on additional outcome ascertainment
Authors: Schomaker M. , Gsponer T. , Estill J. , Fox M. , Boulle A.
Published: July 2013

Loss to follow‐up (LTFU) is a common problem in many epidemiological studies. In antiretroviral treatment (ART) programs for patients with human immunodeficiency virus (HIV), mortality estimates can be biased if the LTFU mechanism is non‐ignorable, that is, mortality differs between lost and retained patients. In this setting, routine procedures for handling missing data may lead to biased estimates. To appropriately deal with non‐ignorable LTFU, explicit modeling of the missing data mechanism is needed. This can be based on additional outcome ascertainment for a sample of patients LTFU, for example, through linkage to national registries or through survey‐based methods. In this paper, we demonstrate how this additional information can be used to construct estimators based on inverse probability weights (IPW) or multiple imputation. We use simulations to contrast the performance of the proposed estimators with methods widely used in HIV cohort research for dealing with missing data. The practical implications of our approach are illustrated using South African ART data, which are partially linkable to South African national vital registration data. Our results demonstrate that while IPWs and proper imputation procedures can be easily constructed from additional outcome ascertainment to obtain valid overall estimates, neglecting non‐ignorable LTFU can result in substantial bias. We believe the proposed estimators are readily applicable to a growing number of studies where LTFU is appreciable, but additional outcome data are available through linkage or surveys of patients LTFU. Copyright © 2013 John Wiley & Sons, Ltd.
Managing contracts for fairness in buyer–supplier exchanges
Authors: Poppo Laura , Zhou Kevin Zheng
Published: July 2013

Despite the centrality of fairness in the moral and social fabric of governance, few studies relate fairness to contracting research. This paper assesses whether fairness accounts for the effects of contractual complexity and contractual recurrence on exchange performance. Based on a sample of 283 buyer–supplier dyads, we find that procedural fairness partially mediates the effect of contractual complexity, whereas distributive fairness partially mediates the effect of contractual recurrence in fostering exchange performance. Moreover, monitoring better supports the use of contractual complexity, whereas socializing better supports the use of contractual recurrence in enhancing fairness perceptions. These results suggest that contractual design must go beyond its safeguarding function to establish a fair frame of reference, and managers should complement contracts with appropriate practices (e.g., monitoring or socializing). Copyright © 2013 John Wiley & Sons, Ltd.
Crystal Plasticity Study of the Effect of the Initial Orientation on the Indentation Surface Profile Patterns and Micro‐Textures of Aluminum Single Crystal
Authors: Liu Mao , Lu Cheng , Tieu Anh Kiet , Deng Guanyu Y.
Published: July 2013

A crystal plasticity finite element method (CPFEM) model has been developed to investigate the effect of the initial orientation on the surface profile patterns of aluminum single crystal during nano‐indentation. The CPFEM model of nano‐indentation has been validated by comparison with experimental observations. The load‐displacement curve from the simulation with the same initial orientation from the report have been analyzed and the calculated values of Young's modulus agrees with that from the report also. Fourfold, twofold, and threefold piling‐up patterns were captured on the (001), (011), and (111) initial oriented surfaces after indentation. The slip traces were analyzed to provide detailed explanations of the anisotropy of the piling‐up patterns and the pole figures were calculated after being unloading. It is found the direction of rotation of the pole figures is opposite each other when a different cutting plane is chosen.
Microstructural Characterization of P91 Steel in the Virgin, Service Exposed and Post‐Service Re‐Normalized Conditions
Authors: Li Huijun , Mitchell David
Published: July 2013

P91 steel has been widely used in power generation industry. Generally, P91 creep resisting steel is produced by normalizing and tempering. The normalizing temperature is in the range of 1040–1080°C and tempering temperature is in the range of 750–780°C. The microstructure after tempering is tempered martensite with precipitates of carbides, M23C6, and vanadium/niobium rich carbo‐nitride of the type MX (M = V or Nb and X = C or N). The presence of carbide precipitates improves creep rupture strength due to precipitation hardening. The carbide coarsening and microstructure degradation during service will result in deterioration in creep strength. It is important to understand the microstructural evolution of P91 steel during long‐term operation. In this work, the steels in the virgin condition (normalized and tempered), service exposed (9 years at 600°C) and post service exposed re‐normalized and tempered in an attempt to restore the original microstructure were characterized. A range of microscopy techniques, predominantly TEM, were applied to understand the effect of these thermal histories on the microstructure of the materials.
Study on Experiment and Mechanism of Bottom Blowing CO2 During the LF Refining Process
Authors: Gu Yunling , Wang Haijuan , Zhu Rong , Wang Jing , Lv Ming , Wang Hui
Published: July 2013

In order to explore the metallurgical behavior and mechanism of bottom blowing CO2 in ladle furnace (LF), CO2 was introduced in the LF refining process. The kinetics and thermodynamics of bottom blowing CO2 were investigated and several mathematical models for kinetic study were established. Some exploratory industrial experiments have been conducted with different proportion of CO2 in a 70 ton LF. The results indicated that it could lead to a little oxidation of elements in molten steel with the processing of bottom blowing CO2 compared with Ar stirring. The average oxidation amount of C was in the range of 0.3–0.8 kg. The average oxidation amount of Mn was reduced by 0.0067% and the average oxidation of Al was increased by 0.003%, while the mass fraction of FeO was less than 0.5% in the slag hence it could meet requirements of reductive reaction. Mass transfer of CO in bubble interface or chemical reaction was the possible rate‐determining step by comparing calculated results with experimental results. Compared with bottom blowing Ar, types and compositions of inclusions have no big change, plus, the equal yield density of inclusions has decreased and the cleanness of steel was improved. Therefore, it is possible to use CO2 in LF.
Calibration diagnostics for point process models via the probability integral transform
Authors: Thorarinsdottir Thordis L.
Published: July 2013

We propose the use of the probability integral transform (PIT) for model validation in point process models. The simple PIT diagnostic tools assess the calibration of the model and can detect inconsistencies in both the intensity and the interaction structure. For the Poisson model, the PIT diagnostics can be calculated explicitly. Generally, the calibration may be assessed empirically based on random draws from the model, and the method applies to processes of any dimension. Copyright © 2013 John Wiley & Sons Ltd
What is ‘survivorship’?
Authors: Kirby Roger
Published: July 2013

Inevitably, clinicians tend to focus on the initial diagnosis and treatment of men with prostate cancer and neglect the longer‐term impact of the disease. Copyright © 2013 John Wiley & Sons
Men and masculinity: understanding the challenges for urological cancer
Authors: Bullen Kathryn , Tod David
Published: July 2013

Stereotypical expectations of male behaviours do not always align with the reality of serious life‐threatening illness, particularly urogenital cancer. However, masculine ways of coping can be harnessed to maximise benefit when providing support for men at all stages of the cancer journey. Copyright © 2013 John Wiley & Sons
Benefits of testosterone replacement
Authors: Hackett Geoff
Published: July 2013

In the previous debate article in this issue, endocrinologists Sally Thrower and Bushra Ahmad asked whether intervention with testosterone replacement therapy is appropriate to reverse the effects of ageing in men. Consultant in Sexual Medicine Geoff Hackett responds here by providing evidence from guidelines outlining the beneficial effects of testosterone for hypogonadal men.
‘Survivorship’ in prostate cancer II: the need for ongoing patient support
Authors: Kirby Roger , Forster Paul , Sharp Owen
Published: July 2013

With increasing numbers of men living with prostate cancer for many years, there is a growing need for improved support in the long term. Copyright © 2013 John Wiley & Sons
Management of breast side‐effects in men treated with androgen deprivation therapy
Authors: Lewis Rachel , Khan Atia , Payne Heather
Published: July 2013

In this series, the authors present cases of men being treated with androgen deprivation therapy, and highlight management strategies to prevent and treat associated toxicities. In this third article, the authors consider the management of gynaecomastia and mastalgia. Copyright © 2013 John Wiley & Sons
Measuring social capital change using ripple mapping
Authors: Baker Barbara , Johannes Elaine M.
Published: July 2013

This article provides a detailed description of how to implement a ripple mapping activity to assess youth program effects on community capital and concludes with examples from Maine and Kansas. The maps lead to group reflection on project outcomes and further research and evaluation questions for group members.

The results from five Maine communities showed that youth in schools and community clubs promoted intentional, mutually beneficial relationships with community groups and businesses and increased shared action on community projects. Likewise, youth in five small Kansas towns implemented and evaluated health promotion projects and found through mapping that youth built social capital in addition to awareness, knowledge, and skills in community health promotion. Ripple mapping helped to demonstrate that actions of youth‐adult partnerships in both states improved the built, human, and social capital in small towns.
A community development approach to service‐learning: Building social capital between rural youth and adults
Authors: Henness Steven A. , Ball Anna L. , Moncheski MaryJo
Published: July 2013

Using 4‐H and FFA case study findings, this article explores how community service‐learning supports the building of social capital between rural youth and adults and the positive effects on community viability. Key elements of practice form a community development approach to service‐learning, which opens up doorways for youth to partner with adult leaders and decision makers, gain credibility as resources and problem solvers, address community issues, and raise awareness of the value of school‐ and community‐based youth programs.

Case study evidence suggests that rural 4‐H and FFA youth and adults benefit from the bonding relationships they form through working together to solve community issues over time. Positive community outcomes are noted as well, including increased community capacity and community recognition. By focusing on social capital as a key outcome of community service‐learning, 4‐H youth and community development extension professionals, educators, and other practitioners have contributed to the viability of rural communities.
Social capital and vulnerability from the family, neighborhood, school, and community perspectives
Authors: Williams Bonita , Le Menestrel Suzanne M.
Published: July 2013

This article reviews research and offers program examples for developing social capital in youth with a range of vulnerabilities: emotional, physical, social, and developmental. Protective factors provided by developing social capital at the individual level include access to support networks, transition to employment, and community connectedness.

The authors feature approaches from the cooperative extension system, which links university and community resources, and identify exemplary programs that support social capital development by intervening with families, schools, neighborhoods, and communities.
Engaging young people as a community development strategy in the Wisconsin Northwoods
Authors: Andresen William , Dallapiazza Margaret , Calvert Matthew
Published: July 2013

This chapter focuses on two remote rural communities that engaged young people in meaningful community development efforts to build social capital. One community connected youth to the assets of the community and created opportunities for young adults to strengthen social networks. The other created partnerships and networks to build intergenerational trust. Both communities intentionally engaged young people in these efforts in order to sustain their communities' economic vitality.
Preparation, Structure, and Second‐order Nonlinear Optical Properties of a Borate‐Carboxylic Acid Compound: NH4B[d‐(+)‐C4H4O5]2·H2O
Authors: Chen Zhaohui , Pan Shilie , Jing Qun , Yang Yun , Dong Xiaoyu , Bian Qiang , Han Jian , Dong Lingyun , Yang Zhihua
Published: July 2013

The organic‐inorganic hybrid nonlinear optical (NLO) material NH4B(d‐(+)‐C4H4O5)2·H2O (NBC) was synthesized in a borate‐carboxylic acid system. Its structure was determined by single crystal X‐ray diffraction. It crystallizes in the orthorhombic system, space group Pna21 (No. 33), with cell parameters a = 11.484(6) Å, b = 5.354(3) Å, c = 21.079(12) Å, V = 1296.0(12), Z = 4. It exhibits a three‐dimensional pseudo tunnel structure consisting of fundamental building block [B(d‐(+)‐C4H4O5)2]– anions. The small cavities are occupied by the H2O molecules and NH4+ cations, which stabilize the whole structure by O–H···O and N–H···O hydrogen bonds. The powder X‐ray diffraction (PXRD) of the crystal was also recorded. Elemental analyses, FT‐IR and FT‐Raman spectra analyses, thermal analysis, and diffuse‐reflectance spectra for the compound are also presented, as are band structures and density of states calculation. Nonlinear optical measurements indicate that the material has second harmonic generation (SHG) properties and is phase‐matchable.
Factors associated with maternal near‐miss morbidity and mortality in Kowloon Hospital, Suzhou, China
Authors: Shen Fang‐Rong , Liu Ming , Zhang Xia , Yang Weiwen , Chen You‐Guo
Published: July 2013

Objective

To investigate factors associated with acute maternal morbidity and mortality in Kowloon Hospital, Suzhou, China.

Methods

Data from cases of near‐miss and maternal death between January 2008 and December 2012 were reviewed retrospectively. Maternal characteristics and related factors were identified, and multiple regression analysis was used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

Results

During the study period, there were 18 104 deliveries, 69 near‐miss cases, and 3 maternal deaths. Women who had no health insurance (aOR, 4.55; 95% CI, 0.87–21.8), had fewer than 6 prenatal consultations (aOR, 6.76; 95% CI, 0.76–45.8), were part of a migrant population (aOR, 2.34; 95% CI, 0.45–24.9), or delayed seeking healthcare (aOR, 4.76; 95% CI, 0.89–13.6) had a greater risk of near‐miss morbidity or death. Admission to intensive care (aOR, 6.75; 95% CI, 0.89–34.6) and blood transfusion within 30 min (aOR, 3.79; 95% CI, 0.65–8.67) were protective factors in disease progression.

Conclusion

The factors associated with maternal near‐miss morbidity and mortality were closely related to health insurance and socioeconomic status, suggesting that the government should take an active role in the community in preventing morbidity and mortality in pregnancy.
The Nature of Permanent Post-concussion Symptoms after Mild Traumatic Brain Injury
Authors: King Nigel S. , Kirwilliam Simon
Published: July 2013

Objective: Very few studies have examined permanent post-concussion symptoms (PCSs) after mild traumatic brain injury (MTBI). None have reported the nature of such symptoms. Our recent study was the first to report on a wide range of factors affecting PCSs in a representative sample of such patients. This paper presents the frequencies of the different PCSs experienced by this group and compares them with PCSs at earlier stages post injury.

Method: One hundred consecutively referred patients to a Community Head Injury Service in Buckinghamshire, UK, for the treatment of long-term PCSs after MTBI were invited to participate in the original study. Those consenting to do so (n = 24, mean time post injury = 6.9 years) completed a Rivermead Post Concussion Symptoms Questionnaire. The frequency of the types of symptoms reported is presented. These are then contrasted with comparable PCS presentations at 7–10 days and 6 months post injury from two other studies.

Results: Fatigue was reported by all long-term patients. Poor concentration, sleep disturbance, taking longer to think and irritability were the other most frequently endorsed permanent symptoms. The least reported were blurred/double vision, photophobia, nausea, headache and dizziness. A similar pattern was present in those at earlier stages post injury.

Conclusions: The most common permanent PCSs may be those best conceptualised as the more cognitively and emotionally based symptoms, and the least common the more somatically based ones. There may be some consistency in the nature of PCSs reported over time.
Effect of supplementary calcium phosphate on plasma gastrointestinal hormones in a double-blind, placebo-controlled, cross-over human study
Authors: Trautvetter Ulrike , Jahreis Gerhard
Published: July 2013

Gastrointestinal hormones and Ca are associated with bone metabolism. The objective of the present human study was to determine the effect of calcium phosphate on the postprandial circulation of gastrointestinal hormones. A total of ten men participated in the present double-blind, placebo-controlled, cross-over study. The participants were divided into two groups. Of these, one group consumed bread enriched with 1 g Ca (pentacalcium hydroxy-triphosphate, CaP) daily for 3 weeks. The other group consumed placebo bread. After 2 weeks of washout, the intervention was changed between the groups for another 3 weeks. The subjects consumed a defined diet at the beginning (single administration) and at the end (repeated administration) of the intervention periods, and blood samples were drawn at 0, 30, 60, 120, 180 and 240 min. Between 0 and 30 min, the participants consumed a test meal, with or without CaP. The concentrations of gastrointestinal hormones (glucose-dependent insulinotropic polypeptide, glucagon-like peptide (GLP) 1 and GLP2), insulin and glucose were determined. The AUC of GLP1 (total and active) and GLP2 increased significantly after the repeated CaP administrations compared with that after placebo administration. The AUC of insulin and glucose showed no differences between the CaP and placebo administrations. CaP affects the postprandial plasma concentrations of gastrointestinal hormones through the modulation of the intestinal environment, e.g. bile acids and microbiota.