bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feasibility study of using fall‐off gradients of early and late PET scans for proton range verification
Authors: Cho Jongmin , Grogg Kira , Min Chul Hee , Zhu Xuping , Paganetti Harald , Lee Hyun Cheol , El Fakhri Georges 
Published: March 2017

PurposeWhile positron emission tomography (PET) allows for the imaging of tissues activated by proton beams in terms of monitoring the therapy administered, most endogenous tissue elements are activated by relatively high‐energy protons. Therefore, a relatively large distance off‐set exists between the dose fall‐off and activity fall‐off. However, 16O(p,2p,2n)13N has a relatively low energy threshold which peaks around 12 MeV and also a residual proton range that is approximately 1 to 2 mm. In this phantom study, we tested the feasibility of utilizing the 13N production peak as well as the differences in activity fall‐off between early and late PET scans for proton range verification. One of the main purposes for this research was developing a proton range verification methodology that would not require Monte Carlo simulations.Methods and materialsBoth monoenergetic and spread‐out Bragg peak beams were delivered to two phantoms — a water‐like gel and a tissue‐like gel where the proton ranges came to be approximately 9.9 and 9.1 cm, respectively. After 1 min of postirradiation delay, the phantoms were scanned for a period of 30 min using an in‐room PET. Two separate (Early and Late) PET images were reconstructed using two different postirradiation delays and acquisition times; Early PET: 1 min delay and 3 min acquisition, Late PET: 21 min delay and 10 min acquisition. The depth gradients of the PET signals were then normalized and plotted as functions of depth. The normalized gradient of the early PET images was subtracted from that of the late PET images, to observe the 13N activity distribution in relation to depth. Monte Carlo simulations were also conducted with the same set‐up as the measurements stated previously.ResultsThe subtracted gradients show peaks at 9.4 and 8.6 cm in water‐gel and tissue‐gel respectively for both pristine and SOBP beams. These peaks are created in connection with the sudden change of 13N signals with depth and consistently occur 2 mm upstream to where 13N signals were most abundantly created (9.6 and 8.8 cm in water‐gel and tissue‐gel, respectively). Monte Carlo simulations provided similar results as the measurements.ConclusionsThe subtracted PET signal gradient peaks and the proton ranges for water‐gel and tissue‐gel show distance off‐sets of 4 to 5 mm. This off‐set may potentially be used for proton range verification using only the PET measured data without Monte Carlo simulations. More studies are necessary to overcome various limitations, such as perfusion‐driven washout, for the feasibility of this technique in living patients.
Evaluation of segmentation methods on head and neck CT: Auto‐segmentation challenge 2015
Authors: Raudaschl Patrik F. , Zaffino Paolo , Sharp Gregory C. , Spadea Maria Francesca , Chen Antong , Dawant Benoit M. , Albrecht Thomas , Gass Tobias , Langguth Christoph , Lüthi Marcel , Jung Florian , Knapp Oliver , Wesarg Stefan , Mannion‐Haworth Richard , Bowes Mike , Ashman Annaliese , Guillard Gwenael , Brett Alan , Vincent Graham , Orbes‐Arteaga Mauricio , Cárdenas‐Peña David , Castellanos‐Dominguez German , Aghdasi Nava , Li Yangming , Berens Angelique , Moe Kris , Hannaford Blake , Schubert Rainer , Fritscher Karl D. 
Published: March 2017

PurposeAutomated delineation of structures and organs is a key step in medical imaging. However, due to the large number and diversity of structures and the large variety of segmentation algorithms, a consensus is lacking as to which automated segmentation method works best for certain applications. Segmentation challenges are a good approach for unbiased evaluation and comparison of segmentation algorithms.MethodsIn this work, we describe and present the results of the Head and Neck Auto‐Segmentation Challenge 2015, a satellite event at the Medical Image Computing and Computer Assisted Interventions (MICCAI) 2015 conference. Six teams participated in a challenge to segment nine structures in the head and neck region of CT images: brainstem, mandible, chiasm, bilateral optic nerves, bilateral parotid glands, and bilateral submandibular glands.ResultsThis paper presents the quantitative results of this challenge using multiple established error metrics and a well‐defined ranking system. The strengths and weaknesses of the different auto‐segmentation approaches are analyzed and discussed.ConclusionsThe Head and Neck Auto‐Segmentation Challenge 2015 was a good opportunity to assess the current state‐of‐the‐art in segmentation of organs at risk for radiotherapy treatment. Participating teams had the possibility to compare their approaches to other methods under unbiased and standardized circumstances. The results demonstrate a clear tendency toward more general purpose and fewer structure‐specific segmentation algorithms.
A Novel SiO2‐Supported Fluorine Modified Chromium–Vanadium Bimetallic Catalyst for Ethylene Polymerization and Ethylene/1‐Hexene Copolymerization
Authors: Sun Qiaoqiao , Wang Lisong , Cheng Ruihua , Liu Zhen , He Xuelian , Zhao Ning , Liu Boping 
Published: March 2017

AbstractPhillips catalyst is one of the most significant industrial ethylene polymerization catalysts. Chemical modifications have been carried out to tune the Phillips catalyst performance and improve the polyethylene properties. After the modification of the catalyst by fluorine, the polyethylene product with higher molecular weight (MW) and narrower molecular weight distribution (MWD) is suitable for producing automobile fuel tanks. Vanadium containing Phillips catalyst enhances α‐olefin incorporation and MW regulation. In present work, fluorine modified and unmodified chromium–vanadium (Cr–V) bimetallic catalysts are prepared and explored. Compared with the fluorine‐free catalyst, the activities of F‐modified bimetallic catalysts slightly decrease with the increasing MW of the product and the hydrogen response increases slightly. Due to the synergistic effect of the chromium, vanadium and fluorine on the silica gel support, the short‐chain branch distribution (SCBD) of copolymers from F‐modified Cr–V bimetallic catalyst (Cr–V–F)600 is more beneficial than that of Cr–V bimetallic catalyst (Cr–V)600 and F‐modified Cr–V bimetallic catalyst (Cr–V–F)500. The fluorination of Cr–V bimetallic catalysts has not only preserved the high polyethylene activity of bimetallic active sites but also produced the advantage of the high MW ability from fluorine.
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Non‐water‐suppressed short‐echo‐time magnetic resonance spectroscopic imaging using a concentric ring k‐space trajectory
Authors: Emir Uzay E. , Burns Brian , Chiew Mark , Jezzard Peter , Thomas M. Albert 
Published: March 2017

Water‐suppressed MRS acquisition techniques have been the standard MRS approach used in research and for clinical scanning to date. The acquisition of a non‐water‐suppressed MRS spectrum is used for artefact correction, reconstruction of phased‐array coil data and metabolite quantification. Here, a two‐scan metabolite‐cycling magnetic resonance spectroscopic imaging (MRSI) scheme that does not use water suppression is demonstrated and evaluated. Specifically, the feasibility of acquiring and quantifying short‐echo (TE = 14 ms), two‐dimensional stimulated echo acquisition mode (STEAM) MRSI spectra in the motor cortex is demonstrated on a 3 T MRI system. The increase in measurement time from the metabolite‐cycling is counterbalanced by a time‐efficient concentric ring k‐space trajectory. To validate the technique, water‐suppressed MRSI acquisitions were also performed for comparison. The proposed non‐water‐suppressed metabolite‐cycling MRSI technique was tested for detection and correction of resonance frequency drifts due to subject motion and/or hardware instability, and the feasibility of high‐resolution metabolic mapping over a whole brain slice was assessed. Our results show that the metabolite spectra and estimated concentrations are in agreement between non‐water‐suppressed and water‐suppressed techniques. The achieved spectral quality, signal‐to‐noise ratio (SNR) > 20 and linewidth <7 Hz allowed reliable metabolic mapping of five major brain metabolites in the motor cortex with an in‐plane resolution of 10 × 10 mm2 in 8 min and with a Cramér‐Rao lower bound of less than 20% using LCModel analysis. In addition, the high SNR of the water peak of the non‐water‐suppressed technique enabled voxel‐wise single‐scan frequency, phase and eddy current correction. These findings demonstrate that our non‐water‐suppressed metabolite‐cycling MRSI technique can perform robustly on 3 T MRI systems and within a clinically feasible acquisition time.
Deploying WLAN service with OpenFlow technology
Authors: Hsu Huai‐Wen , Huang Kuei‐Li , Kao Yi‐Chih , Tsai Shi‐Chun , Lin Yi‐Bing 
Published: March 2017

SummaryIn this paper, we proposed a feasible software‐defined networking (SDN) wireless local area network (WLAN) solution that leverages OpenFlow technique and provides affordable centralized WLAN service without the proprietary restrictions of centralized thin access point WLAN architecture. On the basis of an SDN‐enabled WLAN architecture with fat access points, we implement and deploy a wireless network test bed, where network administrators can exploit the extensibility and flexibility of OpenFlow‐based SDN switches and controller. Service providers can develop customized application modules and required features. We build our system with open sources and commercial off‐the‐shelf hardware and develop a mechanism to control wireless bandwidth. Field experimental results show that our SDN wireless bandwidth control application can effectively manage bandwidth in a dynamic and flexible way via the SDN WLAN.
Approximating the large sparse matrix exponential using incomplete orthogonalization and Krylov subspaces of variable dimension
Authors: Vo Huy D. , Sidje Roger B. 
Published: March 2017

SummaryKrylov subspace approximations to the matrix exponential are popularly used with full orthogonalization instead of incomplete orthogonalization, even though the latter strategy is known to reduce the cost by truncating the recurrences of the modified Gram–Schmidt process. This study combines such a strategy with an adaptive step‐by‐step integration scheme that allows both the stepsize and the dimension of the Krylov subspace to vary. A convergence analysis is done. Numerical results on test problems drawn from systems biology and computer systems show a significant speedup over the standard implementation with full orthogonalization and fixed dimension.
Tetrahydropyranyl: A Non‐aromatic, Mild‐Acid‐Labile Group for Hydroxyl Protection in Solid‐Phase Peptide Synthesis
Authors: Sharma Anamika , Ramos‐Tomillero Iván , El‐Faham Ayman , Rodríguez Hortensia , de la Torre Beatriz G. , Albericio Fernando 
Published: March 2017

AbstractThe use of the tetrahydropyranyl (Thp) group for the protection of serine and threonine side‐chain hydroxyl groups in solid‐phase peptide synthesis has not been widely investigated. Ser/Thr side‐chain hydroxyl protection with this acid‐labile and non‐aromatic moiety is presented here. Although Thp reacts with free carboxylic acids, it can be concluded that to introduce Thp ethers at the hydroxyl groups of N‐protected Ser and Thr, protection of the C‐terminal carboxyl group is unnecessary due to the lability of Thp esters. Thp‐protected Ser/Thr‐containing tripeptides are synthesized and the removal of Thp studied in low concentrations of trifluoroacetic acid in the presence of cation scavengers. Given its general stability to most non‐acidic reagents, improved solubility of its conjugates and ease with which it can be removed, Thp emerges as an effective protecting group for the hydroxyl groups of Ser and Thr in solid‐phase peptide synthesis.
Effect of Ziziphus jujube Fruit Infusion on Lipid Profiles, Glycaemic Index and Antioxidant Status in Type 2 Diabetic Patients: A Randomized Controlled Clinical Trial
Authors: Yazdanpanah Zeinab , Ghadiri‐Anari Akram , Mehrjardi Alireza Vahidi , Dehghani Ali , Zardini Hadi Zare , Nadjarzadeh Azadeh 
Published: March 2017

This study was designed to assess the effects of Ziziphus jujube fruit (ZJF) infusion on lipid profiles, glycaemic control and antioxidant status in patients with type 2 diabetes mellitus (T2DM). In this randomized controlled clinical trial, 116 participants with T2DM (older than 30 years) were assigned to consume a balanced diet or diet plus ZJF infusion (10 g/100 mL boiling water) three times/day before main meals for 12 weeks. Diet was designed to be energy restricted (500 kcal/day deficit from estimated energy requirements), and macronutrient content was similar in both groups (55% carbohydrate, 15% protein and 30% fat). The consumption of ZJF infusion compared with the control group was associated with significant improvement in glycosylated haemoglobin (−0.68 ± 0.65 vs. −0.44 ± 0.55%; p = 0.03), total cholesterol (−24.29 ± 28.89 vs. −11.21 ± 29.98 mg/dL; p = 0.02), triglycerides (−43.3 ± 39.26 vs. −27.16 ± 46.84 mg/dL; p = 0.05), low‐density lipoprotein cholesterol (−19.85 ± 27.62 vs. −6.55 ± 27.82 mg/dL; p = 0.01), low‐density lipoprotein cholesterol/high‐density lipoprotein cholesterol (−0.56 ± 0.80 vs. −0.2 ± 0.72; p = 0.01) and total cholesterol to high‐density lipoprotein cholesterol ratios (−0.73 ± 0.94 vs. −0.35 ± 0.77; p = 0.02). ZJF had beneficial effects on glycosylated haemoglobin and lipid profile in T2DM patients. Further research is needed to identify the mechanism of ZJF action on glucose and lipid metabolism. Copyright © 2017 John Wiley & Sons, Ltd.
Finite‐time control for LPV systems with parameter‐varying time delays and exogenous disturbances
Authors: Hu Yanmei , Duan Guangren , Tan Feng 
Published: March 2017

SummaryIn this paper, we consider the stability analysis and control synthesis of finite‐time boundedness problems for linear parameter‐varying (LPV) systems subject to parameter‐varying time delays and external disturbances. First, the concepts of uniform finite‐time stability and uniform finite‐time boundedness are introduced to LPV systems. Then, sufficient conditions, which guarantee LPV systems with parameter‐varying time delays finite‐time bounded, are presented by using parameter‐dependent Lyapunov–Krasovskii functionals and free‐weight matrix technologies. Moreover, on the basis of the results on the uniform finite‐time boundedness, the parameter‐dependent state feedback controllers are designed to finite‐time stabilize LPV systems. Both analysis and synthesis conditions are delay‐dependent, and they are formulated in terms of linear matrix inequalities by using efficient interior‐point algorithms. Finally, results obtained in simulation demonstrate the effectiveness of the proposed approach. Copyright © 2017 John Wiley & Sons, Ltd.
Profiles of Transformative Engagement: Identification, Description, and Relation to Learning and Instruction
Authors: PUGH KEVIN J. , BERGSTROM CASSENDRA M. , SPENCER BRYDEN 
Published: March 2017

ABSTRACTTransformative experience refers to learning episodes in which students use ideas from the science classroom to see and experience the world differently in their everyday lives. The construct is defined by three characteristics: (1) motivated use (application of learning in “free‐choice” contexts), (2) expansion of perception (seeing objects, events, or issues through the lens of the content), and (3) experiential value (valuing content for how it enriches everyday experience). To enhance conceptions of engagement in science, the current study sought to identify and describe profiles oftransformativeengagement by investigating levels and combinations of the three characteristics of transformative experience. In addition, it examined how learning and instruction relate to these profiles. Sixty‐five middle school science students were interviewed and responses were coded for the three characteristics of transformative experience. Scores on these characteristics were used as variables in cluster analysis and representative clusters were identified. Profiles of transformative engagement were developed and described based on these clusters. Profiles representing greater transformative engagement were associated with greater learning. Relative to a comparison condition, instruction designed to foster transformative experience yielded a higher percentage of students in the profile reflecting engagement in a genuine transformative experience.
Ethische Aspekte der klinischen Prüfung bei seltenen Erkrankungen
Authors: Hasford Joerg , Koch Armin 
Published: March 2017

Zusammenfassung
Seltene Erkrankungen, an denen allein in Deutschland geschätzte 4 Mio. Menschen leiden, sind in den Blickpunkt des Interesses der Therapieforschung gerückt. Die klinische Prüfung von Arzneimitteln ist sehr detailliert in Gesetzen, Verordnungen und ethischen Konventionen geregelt, die keine Sonderregelungen für klinische Prüfungen bei seltenen Erkrankungen vorsehen. Somit gelten für die ethische Bewertung entsprechender Anträge die gleichen Standards wie für häufige Krankheiten. Dies macht auch Sinn, da ethische Standards bezüglich Aufklärung, Einwilligung und Studiendurchführung, die zudem meist im Recht kodifiziert sind, nicht von der Häufigkeit der Erkrankung abhängen können. Besondere Bedeutung im Kontext der ethischen Bewertung spielen biometrische Aspekte wie Studiendesign und statistische Auswertung, da nicht aussagekräftig angelegte klinische Forschung mit Menschen per se unethisch ist. Auf die Probleme der Fallzahlschätzung und von Pilotstudien wird näher eingegangen. Pilotstudien sollten nach Möglichkeit vermieden werden. Bei der Fallzahlschätzung sollte nicht von überoptimistischen Annahmen ausgegangen werden und keine Erhöhung der üblichen Irrtumswahrscheinlichkeit von 5 % erfolgen.
Anhedonia predicts poor psychosocial functioning: Results from a large cohort of patients treated for major depressive disorder by general practitioners
Authors: Vinckier F. , Gourion D. , Mouchabac S. 
Published: March 2017

AbstractBackground:Anhedonia is a core symptom of major depression and a key prognostic factor that is often poorly explored in clinical trials of major depressive disorder (MDD). Beyond symptomatic remission, psychosocial functioning also reveals difficulty in achieving remission in patients with MDD. The main objective of this study was to explore the interrelationships between social functioning and anhedonia on a longitudinal basis.Methods:In total, 1570 outpatients treated for MDD with agomelatine were included. Severity of depression and levels of anhedonia and of psychosocial functioning were assessed at inclusion and at 10–14 weeks, with specific standardized scales (MADRS, QFS, SHAPS, CGI). Multivariate regression and mediation analyses were performed.Results:Using multivariate regression, we showed that improvement of anhedonia was the strongest predictor of improvement in psychosocial functioning (odds ratio = 7.3 [4.3–12.1] P < 0.0001). In addition, mediation tests confirmed that the association between improvement of depressive symptoms and improvement of social functioning was significantly underpinned by the improvement of anhedonia over time. Finally, we explored the determinants of the dissociation of the response, i.e., the persistence of psychosocial dysfunctioning despite a symptomatic response to antidepressant treatment, which remains a widespread situation in clinical practice. We showed that this dissociation was strongly predicted by persistence of anhedonia.Conclusion:Our results suggest that anhedonia is one of the strongest predictors of psychosocial functioning, along with symptomatic remission, and should be carefully assessed by health professionals, in order to optimize pharmacological as well as non-pharmacological management of depression.
Comparison of 3 mm versus 4 mm rigid endoscope in diagnostic nasal endoscopy
Authors: Neel Gregory S. , Kau Ryan L. , Bansberg Stephen F. , Lal Devyani 
Published: March 2017

ObjectiveCompare nasal endoscopy with 3 mm versus conventional 4 mm rigid 30° endoscopes for visualization, patient comfort, and examiner ease.MethodsTen adults with no previous sinus surgery underwent bilateral nasal endoscopy with both 4 mm and 3 mm endoscopes (resulting in 20 paired nasal endoscopies). Visualization, patient discomfort and examiner's difficulty were assessed with every endoscopy. Sino‐nasal structures were checked on a list if visualized satisfactorily. Patients rated discomfort on a standardized numerical pain scale (0–10). Examiners rated difficulty of examination on a scale of 1–5 (1 = easiest).ResultsVisualization with 3 mm endoscope was superior for the sphenoid ostium (P = 0.002), superior turbinate (P = 0.007), spheno‐ethmoid recess (P = 0.006), uncinate process (P = 0.002), cribriform area (P = 0.007), and Valve of Hasner (P = 0.002). Patient discomfort was not significantly different for 3 mm vs. 4 mm endoscopes but correlated with the examiners' assessment of difficulty (r = 0.73). The examiner rated endoscopy with 4 mm endoscopes more difficult (P = 0.027).ConclusionsThe 3 mm endoscope was superior in visualizing the sphenoid ostium, superior turbinate, spheno‐ethmoid recess, uncinate process, cribriform plate, and valve of Hasner. It therefore may be useful in assessment of spheno‐ethmoid recess, nasolacrimal duct, and cribriform area pathologies. Overall, patients tolerated nasal endoscopy well. Though patient discomfort was not significantly different between the endoscopes, most discomfort with 3 mm endoscopes was noted while examining structures difficult to visualize with the 4 mm endoscope. Patients' discomfort correlated with the examiner's assessment of difficulty.
Quantum nonlinear Schrödinger equation. I. Intertwining operators
Authors: Gutkin Eugène 
Published: March 2017

We consider the quantum nonlinear Schrödinger equation (NLS) as a model of the quantum (nonrelativistic) field theory in 1 + 1 dimensions. In this paper we develop a calculus of intertwining operators for the NLS. This calculus will be used in subsequent publications to solve explicitly an initial value problem for the NLS.

Résumé
On s’occupe ici de l’équation de Schrödinger non linéaire quanitio (NLS) comme un modèle de la théorie quantique (non relativiste) des champs en 1 + 1 dimensions. Dans ce travail nous présentons un calcul des opérateurs entrelaçants pour le NLS. Ce calcul sera utilisé dans les publications suivantes à donner la solution explicite d’un problème de valeur initiale pour le NLS.
Vers une notion de dérivation fonctionnelle causale
Authors: Fliess Michel 
Published: March 2017

The notions of derivatives stemming from classical functional analysis do not always mesh well with dynamic evolution. We show here that a derivative, which was introduced by R. Ree in relation with K.-T. Chen’s iterated integrals, possesses an infinitesimal interpretation that takes most naturally causality into account. For this derivation, the non-commutative generating power series expansions are the corresponding Taylor series expansions.

Résumé
Les notions de dérivations issues de l’analyse fonctionnelle classique ne conviennent pas toujours à une évolution dynamique. Nous montrons qu’une dérivation, introduite par R. Ree à propos des intégrales itérées de K.-T. Chen, possède une interprétation infinitésimale qui prend naturellement en compte la causalité. Pour cette dérivation, le développement en série génératrice non commutative apparaît comme un développement taylorien.