bluuebunny/crossref_metadata_2025 huggingface dataset:
On the seismic performances of rigid block‐like structures coupled with an oscillating mass working as a TMD
Authors: Simoneschi Giorgia , Geniola Alessandro , de Leo Andrea M. , Di Egidio Angelo
Published: January 2017

In this paper, the effects of a mass damper on the rocking motion of a non‐symmetric rigid block‐like structure, subject to different seismic excitation, are investigated. The damper is modelled as a single degree of freedom oscillating mass, running at the top of the block and connected to it by a linear visco‐elastic device. The equations of rocking motion, the uplift and the impact conditions are derived. A nondimensionalisation of the governing equations is performed with the aim to obtain an extensive parametric analysis. The results are achieved by numerical integration of these equations. The slenderness and the base of the rigid block, and the eccentricity of the centre of mass are taken as variable parameters in the analyses. The main objective of the study is to check the performance of the damper versus the spectral characteristics of the seismic input. Three earthquake registrations with different frequency contents are used in the analyses. The results show that the presence of the mass damper leads to different levels of improvement of the response of the system, depending on the spectral characteristics of the seismic input. Curves providing the overturning slenderness of blocks of specific sizes versus the characteristics of the TMD are obtained. Copyright © 2017 John Wiley & Sons, Ltd.
Cholinergic signaling in myelination
Authors: Fields R. Douglas , Dutta Dipankar J. , Belgrad Jillian , Robnett Maya
Published: January 2017

There is a long history of research on acetylcholine (ACh) function in myelinating glia, but a resurgence of interest recently as a result of the therapeutic potential of manipulating ACh signaling to promote remyelination, and the broader interest in neurotransmitter signaling in activity‐dependent myelination. Myelinating glia express all the major types of muscarinic and nicotinic ACh receptors at different stages of development, and acetylcholinesterase and butyrylcholinesterase are highly expressed in white matter. This review traces the history of research on ACh signaling in Schwann cells, oligodendrocytes, and in the myelin sheath, and summarizes current knowledge on the intracellular signaling and functional consequences of ACh signaling in myelinating glia. Implications of ACh in diseases, such as Alzheimer's disease, multiple sclerosis, and white matter toxicity caused by pesticides are considered, together with an outline of major questions for future research. GLIA 2017;65:687–698
One‐pot green synthesis of benzoxazole derivatives through molecular sieve‐catalyzed oxidative cyclization reaction
Authors: Chang Weichieh , Sun Yukai , Huang Yungtzung
Published: January 2017

An one‐pot approach to benzoxazole ring from 2‐aminophenol and aldehydes utilizing molecular sieve as the catalyst have been developed. The new oxidative cyclization reaction excluded the usage of hazardous chemical reagents, transition‐metal catalysts, chemical oxidants, or strong acids, and, therefore, reduced the production of toxic chemical waste. This offers an environmentally friendly pathway for the synthesis of various benzoxazole derivatives.
A high‐efficient method for the amidation of carboxylic acids promoted by triphenylphosphine oxide and oxalyl chloride
Authors: Jiang Lixue , Yu Jing , Niu Fanfan , Zhang Derundong , Sun Xiaoling
Published: January 2017

A effective amidation reaction of carboxylic acids with various amines promoted by triphenylphosphine oxide and oxalyl chloride under mild and neutral conditions has been developed. The feature of this procedure was the using and recycling of triphenylphosphine oxide at room temperature in 0.5 h. Furthermore a plausible mechanism also be deduced with the help of 31P NMR spectroscopy.
Coastal aquifer response to extreme storm events in Emilia‐Romagna, Italy
Authors: Giambastiani Beatrice M.S. , Colombani Nicolò , Greggio Nicolas , Antonellini Marco , Mastrocicco Micòl
Published: January 2017

With global warming and sea level rise, many coastal systems will experience increased levels of inundation and storm flooding, especially along sandy lowland coastal areas, such as the Northern Adriatic coast (Italy). Understanding how extreme events may directly affect groundwater hydrology in shallow unconfined coastal aquifers is important to assess coastal vulnerability and quantify freshwater resources. This study investigates shallow coastal aquifer response to storm events. The transitory and permanent effects of storm waves are evaluated through the real time monitoring of groundwater and soil parameters, in order to characterize both the saturated and unsaturated portions of the coastal aquifer of Ravenna and Ferrara (southern Po Delta, Italy). Results highlight a general increase in hydraulic head and soil moisture, along with a decrease in groundwater salinity and pore water salinity due to rainfall infiltration during the 2 days storm event. The only exceptions are represented by the observation wells in proximity to the coastline (within 100 m), which recorded a temporary increase in soil and water salinity caused by the exceptional high waves, which persist on top of the dune crest during the storm event. This generates a saline plume that infiltrates through the vadose zone down to the saturated portion of the aquifer causing a temporary disappearance of the freshwater lens generally present, although limited in size, below the coastal dunes. Despite the high hydraulic conductivity, the aquifer system does not quickly recover the pre‐storm equilibrium and the storm effects are evident in groundwater and soil parameters after 10 days past the storm overwash recess.
Targeting Cancer Stem Cells with Small Molecules
Authors: Müller Sebastian , Cañeque Tatiana , Acevedo Verónica , Rodriguez Raphaël
Published: January 2017

Cancers arise as a result of physiological imbalances and subsequent uncontrolled cell division. Cancer initiation requires a set of biochemical alterations, including some occurring at the genetic and epigenetic levels. Thus, tumors are heterogeneous in nature making it challenging to selectively target different cancer cells by means of small molecule intervention. The paradigm of cancer stem cells (CSCs) describes subpopulations of cells with high self‐renewal and tumor‐seeding capacity. These cells, typically refractory to conventional therapies, can give rise to relapse after treatment. Combinatorial strategies, including drugs that selectively target this population of cells, have emerged in recent years. Here, we review how discovery‐based – unbiased – screening approaches have helped identify small molecules that specifically target CSCs. We also highlight biological pathways characteristic of CSCs that can potentially be selectively targeted in a hypothesis‐driven manner by small molecules. We describe molecules that effectively target CSCs and emphasize what is known about their biological modes of action. The diversity and complexity of biochemical processes that CSCs may be addicted to, raises the question of how selective targeting of these pathways can be achieved. This challenge may be addressed by the continuing production of structurally complex and diverse small molecules using target and diversity‐oriented synthesis approaches.
Global exploration of isomers and isomerization channels on the quantum chemical potential energy surface of H3CNO3
Authors: Ohno Koichi , Kishimoto Naoki , Iwamoto Takeaki , Satoh Hiroko
Published: January 2017

Global exploration of isomers and isomerization channels on the quantum chemical potential energy surface (PES) is performed for H3CNO3 using the Scaled Hypersphere Search‐Anharmonic Downward Distortion Following (SHS‐ADDF) method. The molecular formula of H3CNO3 includes functional groups of CH3, OH, NH2, COOH, NO, NO2, and NO3, which are very important in connection with amino acids and NOx. Geometrical structures and interconversion pathways are disclosed after 18719781 force calculations and 534726 Hessian calculations at the level of B3LYP/6‐31G(d). The explored results are confirmed to be valid, especially for the important lower energy regions, by re‐optimization at the higher level of B3LYP/6‐311++G(d,p). A global reaction route‐mapping using SHS‐ADDF demonstrates the entire view and undeveloped landscapes on PES of H3CNO3. Typical compounds of H3CNO3, aminoxy formic acid, hydroxycarbamic acid, aminoperformic acid, hydroxymethyl nitrite, nitromethanol, methyl nitrate, methyl peroxynitrite, and dioxaziridine, are well separated from others by very high energy‐barriers. The stable‐most conformer of H3CNO3 is difficult to be determined, because of seven structures existing with nearly the same energies within 5.7 kJ/mol at the level of CCSD(T)/aug‐cc‐pVTZ. © 2017 Wiley Periodicals, Inc.
Prediction of excited‐state properties of oligoacene crystals using polarizable continuum model‐tuned range‐separated hybrid functional approach
Authors: Hu Zhubin , Zhou Bin , Sun Zhenrong , Sun Haitao
Published: January 2017

A methodology combining the polarizable continuum model and optimally‐tuned range‐separated (RS) hybrid functional was proposed for the quantitative characterization of the excited‐state properties in oligoacene (from anthracene to hexacene) crystals. We show that it provides lowest vertical singlet and triplet excitation energies, singlet‐triplet gap, and exciton binding energies in very good agreement with the available experimental data. We further find that it significantly outperforms its non‐tuned RS counterpart and the widely used B3LYP functional, and even many‐body perturbation theory within the GW approximation (based on a PBE starting point). Hence, this approach provides an easily applicable and computationally efficient tool to study the excited‐state properties of organic solids of complexity. © 2017 Wiley Periodicals, Inc.
Rigidity and flexibility in the tetrasaccharide linker of proteoglycans from atomic‐resolution molecular simulation
Authors: Ng Cathy , Nandha Premnath Padmavathy , Guvench Olgun
Published: January 2017

Proteoglycans (PGs) are covalent conjugates between protein and carbohydrate (glycosaminoglycans). Certain classes of glycosaminoglycans such as chondroitin sulfate/dermatan sulfate and heparan sulfate utilize a specific tetrasaccharide linker for attachment to the protein component: GlcAβ1‐3Galβ1‐3Galβ1‐4Xylβ1‐O‐Ser. Toward understanding the conformational preferences of this linker, the present work used all‐atom explicit‐solvent molecular dynamics (MD) simulations combined with Adaptive Biasing Force (ABF) sampling to determine high‐resolution, high‐precision conformational free energy maps ΔG(φ, ψ) for each glycosidic linkage between constituent disaccharides, including the variant where GlcA is substituted with IdoA. These linkages are characterized by single, predominant (> 97% occupancy), and broad (45° × 60° for ΔG(φ, ψ) < 1 kcal/mol) free‐energy minima, while the Xyl‐Ser linkage has two such minima similar in free‐energy, and additional flexibility from the Ser sidechain dihedral. Conformational analysis of microsecond‐scale standard MD on the complete tetrasaccharide‐O‐Ser conjugate is consistent with ABF data, suggesting (φ, ψ) probabilities are independent of the linker context, and that the tetrasaccharide acts as a relatively rigid unit whereas significant conformational heterogeneity exists with respect to rotation about bonds connecting Xyl to Ser. © 2017 Wiley Periodicals, Inc.
“Watch out!”: Effects of instructed threat and avoidance on human free‐operant approach–avoidance behavior
Authors: Schlund Michael W. , Treacher Kay , Preston Oli , Magee Sandy K. , Richman David M. , Brewer Adam T. , Cameron Gemma , Dymond Simon
Published: January 2017

Approach–avoidance paradigms create a competition between appetitive and aversive contingencies and are widely used in nonhuman research on anxiety. Here, we examined how instructions about threat and avoidance impact control by competing contingencies over human approach–avoidance behavior. Additionally, Experiment 1 examined the effects of threat magnitude (money loss amount) and avoidance cost (fixed ratio requirements), whereas Experiment 2 examined the effects of threat information (available, unavailable and inaccurate) on approach–avoidance. During the task, approach responding was modeled by reinforcing responding with money on a FR schedule. By performing an observing response, participants produced an escalating “threat meter”. Instructions stated that the threat meter levels displayed the current probability of losing money, when in fact loss only occurred when the level reached the maximum. Instructions also stated pressing an avoidance button lowered the threat level. Overall, instructions produced cycles of approach and avoidance responding with transitions from approach to avoidance when threat was high and transitions back to approach after avoidance reduced threat. Experiment 1 revealed increasing avoidance cost, but not threat magnitude, shifted approach–avoidance transitions to higher threat levels and increased anxiety ratings, but did not influence the frequency of approach–avoidance cycles. Experiment 2 revealed when threat level information was available or absent earnings were high, but earnings decreased when inaccurate threat information was incompatible with contingencies. Our findings build on prior nonhuman and human approach–avoidance research by highlighting how instructed threat and avoidance can impact human AA behavior and self‐reported anxiety.
How suboptimal is suboptimal choice?
Authors: Hinnenkamp Jay E. , Shahan Timothy A. , Madden Gregory J.
Published: January 2017

In a frequently used suboptimal‐choice procedure pigeons choose between an alternative that delivers three food pellets with p = 1.0 and an alternative that delivers ten pellets with p = 0.2. Because pigeons reliably choose the probabilistic (suboptimal) alternative, the procedure has been proposed as a nonhuman analog of human gambling. The present experiments were conducted to evaluate two potential threats to the validity of this procedure. Experiments 1 and 2 evaluated if pigeons obtained food at a lower unit price (i.e., pecks per pellet) on the suboptimal alternative than on the optimal alternative. When pigeons worked under this suboptimal procedure they all preferred the suboptimal alternative despite some pigeons paying a higher price for food on that alternative. In Experiment 2, when the unit price ratio more closely approximated the inverse of the expected value ratio, pigeons continued to prefer the suboptimal alternative despite its economic suboptimality. Experiment 3 evaluated if, in accord with the string‐theory of gambling, the valuation of the suboptimal alternative was increased when pigeons misattributed a subset of the suboptimal no‐food trials to the optimal alternative. When trial sequences were arranged to minimize these possible attribution errors, pigeons still preferred the suboptimal alternative. These data remove two threats to the validity of the suboptimal choice procedure; threats that would have suggested that suboptimal choice reflects economic maximization.
Are positive and negative reinforcement “different”? Insights from a free‐operant differential outcomes effect
Authors: Magoon Michael A. , Critchfield Thomas S. , Merrill Dustin , Newland M. Christopher , Schneider W. Joel
Published: January 2017

Although theoretical discussions typically assume that positive and negative reinforcement differ, the literature contains little unambiguous evidence that they produce differential behavioral effects. To test whether the two types of consequences control behavior differently, we pitted money‐gain positive reinforcement and money‐loss‐avoidance negative reinforcement, scheduled through identically programmed variable‐cycle schedules, against each other in concurrent schedules. Contingencies of response‐produced feedback, normally different in positive and negative reinforcement, were made symmetrical. Steeper matching slopes were produced compared to a baseline consisting of all positive reinforcement. This free‐operant differential outcomes effect supports the notion that that stimulus‐presentation positive reinforcement and stimulus‐elimination negative reinforcement are functionally “different.” However, a control experiment showed that the feedback asymmetry of more traditional positive and negative reinforcement schedules also is sufficient to create a “difference” when the type of consequence is held constant. We offer these findings as a small step in meeting the very large challenge of moving negative reinforcement theory beyond decades of relative quiescence.
Molecular binding of toxic phenothiazinium derivatives, azures to bovine serum albumin: A comparative spectroscopic, calorimetric, and in silico study
Authors: Das Somnath , Islam Md. Maidul , Jana Gopal Chandra , Patra Anirudha , Jha Pradeep K. , Hossain Maidul
Published: January 2017

In this paper, the comparative binding behavior of antimalarial drug azure A, azure B and azure C with bovine serum albumin (BSA) has been studied. The interaction has been confirmed by multispectroscopic (UV, fluorescence, Fourier transform infrared (FT‐IR), and circular dichroism) and molecular docking techniques. The experimental results show that azure B has the highest BSA binding affinity followed by azure A and azure C. The experimental evidence of binding showed a static quenching mechanism in the interaction azures with BSA. The isothermal titration calorimetry result reveals that the binding was exothermic with positive entropy contribution in each case. The thermodynamic parameters ΔH, ΔG, and ΔS at 25°C were calculated, which indicates that the weak van der Waals forces and hydrogen bonding rather than the hydrophobic effect played an important role in the interaction. According to the theory of Förster nonradiative energy transfer, the distance (r) between the donor (BSA) and acceptor azures found to be <7 nm in all the case. The circular dichroism and FT‐IR studies show that the content of α‐helix structure has increased for the azures‐BSA system. Overall, experimental studies characterize the interaction dynamics and energetics of the binding of three toxic analogs towards the physiologically relevant serum albumins. We hope, the outcome of this work will be most helpful for synthesizing a new type of phenothiazinium derivatives of the better therapeutic application.
Whether power holders construe their power as responsibility or opportunity influences their tendency to take advice from others
Authors: De Wit Frank R.C. , Scheepers Daan , Ellemers Naomi , Sassenberg Kai , Scholl Annika
Published: January 2017

Empirical evidence suggests that power elicits a generic tendency to disregard advice. We examined different responses power holders may show in their tendency to take advice depending on the construal of power. We report a field study and an experiment among managers and other powerful professionals (Studies 1 and 2) and an experiment in which participants were assigned to a powerful role (Study 3). Across studies, we found a higher tendency to take advice among those who construed their power as a responsibility rather than as an opportunity. This effect of the construal of power on advice taking was mediated by a heightened perceived value of advice, not by decreased confidence in own judgments or sense of power. Accordingly, the increase in advice taking when power was construed as a responsibility was observed regardless of whether the advice came from subordinates (Study 1), expert advisors (Study 2), or a less powerful teammate (Study 3). This highlights the relevance of considering how power holders construe their power in order to understand their tendency to take advice from others. Copyright © 2017 John Wiley & Sons, Ltd.
Good marriage at home, creativity at work: Family–work enrichment effect on workplace creativity
Authors: Tang Yipeng , Huang Xu , Wang Yongli
Published: January 2017

To advance the understanding of socio‐relational sources of employee creativity, we investigate the effect of a good marriage on workplace creativity. Drawing on family–work enrichment theory, we propose and test the idea that a satisfying marriage boosts a spillover of psychological resources from family to work that enhances employees' workplace creativity. Using survey data collected from 548 spouse–employee–supervisor triads, we find an indirect positive relationship between employees' marital satisfaction and workplace creativity through a spillover of psychological resources from family to work. We also find that this spillover is most pronounced when both employees and their spouses are satisfied with their marriage. The results further demonstrate that the indirect effect of marital satisfaction on workplace creativity through the spillover of psychological resources is significant for employees with a low creative personality, but not for those with a high creative personality. Copyright © 2017 John Wiley & Sons, Ltd.
Shrimp tropomyosin retains antibody reactivity after exposure to acidic condition
Authors: Lasekan Adeseye , Cao Hanjuan , Maleki Soheila , Nayak Balunkeswar (Balu)
Published: January 2017

BACKGROUND

Although shrimp can be found in certain high acid food matrices, the allergenic capacity of shrimp tropomyosin exposed to low pH condition has not been fully clarified. Thus, a model marinade comprising white vinegar adjusted to different pH was used to determine the effects of acid‐induced denaturation on the immunoreactivity of tropomyosin.

RESULTS

Whole shrimp experienced either swelling or shrinkage after marination depending on the vinegar pH and the final muscle pH. The extractability of soluble myofibrillar proteins was reduced significantly among shrimp marinated in vinegar at pH 1.0–3.5, and a substantial amount of tropomyosin was retained in the insoluble pellets. Consequently, the immunoglobulin E (IgE)‐binding capacity of tropomyosin was significantly lower in the soluble protein fraction of shrimp marinated at pH 1.0–3.5 compared with samples marinated at pH 4.8 and control. However, tropomyosin in the insoluble protein fraction of all marinated shrimp showed strong IgE‐binding capacity at all marinating conditions.

CONCLUSION

Thus, tropomyosin in shrimp exposed to low pH condition retained its allergenic capacity owing to the conservation of its linear epitopes. Analysis of the insoluble protein fraction was crucial for the accurate determination of the effect of low pH condition on the immunoreactivity of this allergen. © 2017 Society of Chemical Industry
How open access is crucial to the future of science
Authors: Bolick Josh , Emmett Ada , Greenberg Marc L. , Rosenblum Brian , Peterson A. Townsend
Published: January 2017

A commentary published recently in The Journal of Wildlife Management argued that open access publication has strong negative implications for the future of science. Unfortunately, that commentary was founded in serious and deep misconceptions about the distinctions between open access, commercial, and society publications, and the rigor of peer review in open access journals. To the contrary, open access responds more appropriately than traditional closed publishing venues to the needs and participation of an increasingly global scholarly research community, and peer review by a broader community may in many cases be more rigorous, responding to the increasingly interdisciplinary nature of modern research. We respectfully suggest that The Wildlife Society consider a transition from closed access to open access for The Journal of Wildlife Management, as a means of optimizing and maximizing its role in communications in the field. © 2017 The Wildlife Society.
Learning‐based deformable image registration for infant MR images in the first year of life
Authors: Hu Shunbo , Wei Lifang , Gao Yaozong , Guo Yanrong , Wu Guorong , Shen Dinggang
Published: January 2017

Purpose

Many brain development studies have been devoted to investigate dynamic structural and functional changes in the first year of life. To quantitatively measure brain development in such a dynamic period, accurate image registration for different infant subjects with possible large age gap is of high demand. Although many state‐of‐the‐art image registration methods have been proposed for young and elderly brain images, very few registration methods work for infant brain images acquired in the first year of life, because of (a) large anatomical changes due to fast brain development and (b) dynamic appearance changes due to white‐matter myelination.

Methods

To address these two difficulties, we propose a learning‐based registration method to not only align the anatomical structures but also alleviate the appearance differences between two arbitrary infant MR images (with large age gap) by leveraging the regression forest to predict both the initial displacement vector and appearance changes. Specifically, in the training stage, two regression models are trained separately, with (a) one model learning the relationship between local image appearance (of one development phase) and its displacement toward the template (of another development phase) and (b) another model learning the local appearance changes between the two brain development phases. Then, in the testing stage, to register a new infant image to the template, we first predict both its voxel‐wise displacement and appearance changes by the two learned regression models. Since such initializations can alleviate significant appearance and shape differences between new infant image and the template, it is easy to just use a conventional registration method to refine the remaining registration.

Results

We apply our proposed registration method to align 24 infant subjects at five different time points (i.e., 2‐week‐old, 3‐month‐old, 6‐month‐old, 9‐month‐old, and 12‐month‐old), and achieve more accurate and robust registration results, compared to the state‐of‐the‐art registration methods.

Conclusions

The proposed learning‐based registration method addresses the challenging task of registering infant brain images and achieves higher registration accuracy compared with other counterpart registration methods.
Experimental verification of 4D Monte Carlo simulations of dose delivery to a moving anatomy
Authors: Gholampourkashi Sara , Vujicic Miro , Belec Jason , Cygler Joanna E. , Heath Emily
Published: January 2017

Purpose

To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom.

Methods

We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point‐dose values at the center of the spherical tumor inside the insert. Both a static 4 × 4 cm2 field and a VMAT plan were delivered. Static and 4D Monte Carlo simulations of the treatment deliveries were performed using DOSXYZnrc and a modified version of the defDOSXYZnrc user code that allows modeling of the continuous motion of both machine and patient. DICOM treatment plan files and linac delivery log files were used to generate corresponding input files. The phantom motion recorded by RADPOS during beam delivery was incorporated into the input files for the 4DdefDOSXYZnrc simulations.

Results

For stationary phantom simulations, all point‐dose values from MC simulations at the tumor center agreed within 1% with film and within 2% with RADPOS. More than 98% of the voxels from simulated dose profiles passed a 1D gamma of 2%/2‐mm criteria against measured dose profiles. Similar results were observed when applying a 2D gamma analysis with a 2%/2‐mm criteria to compare 2D dose distributions of Monte Carlo simulations against measurements. For simulations on the moving phantom, MC‐calculated dose values at the center of the tumor were found to be within 1% of film and within 2σ of experimental uncertainties which are 2.8% of the RADPOS measurements. 1D gamma comparisons of the dose profiles were better than 91%, and 2D gamma comparisons of the 2D dose distributions were found to be better than 94%.

Conclusion

Our 4D Monte Carlo method using defDOSXYZnrc can be used to accurately calculate the dose distribution in continuously moving anatomy for various treatment techniques. This work, if extended to deformable anatomies, can be used to reconstruct patient delivered dose for use in adaptive radiation therapy.
Compound speckle model detects anti‐angiogenic tumor response in preclinical nonlinear contrast‐enhanced ultrasonography
Authors: Lowerison Matthew R. , Tse Justin J. , Hague M. Nicole , Chambers Ann F. , Holdsworth David W. , Lacefield James C.
Published: January 2017

Purpose

This paper proposes a method for analyzing the first‐order speckle statistics of nonlinear contrast‐enhanced ultrasound images from tumors.

Methods

Contrast signal intensity is modeled as a compound distribution of exponential probability density functions with a gamma weighting function. The gamma probability weighting function serves as an approximation for log‐normally distributed flow velocities in a vascular network. The model was applied to sub‐harmonic bolus‐injection images acquired from a mouse breast cancer xenograft model treated with murine version bevacizumab.

Results

The area under curve produced using the compound statistical model could more accurately discriminate anti‐VEGF‐treated tumors from untreated tumors than conventional contrast‐enhanced ultrasound image processing. This result was validated with gold standard histological measures of microvascular density. Fractal vessel geometry was estimated using the gamma weighting function and tested against micro‐CT perfusion casting. Treated tumors had a significantly lower vascular fractal dimension than control tumors. Vascular complexity estimated using the ultrasound compound statistical model performed similarly to micro‐CT fractal dimension for discriminating treated from control tumors.

Conclusion

The proposed technique can quantify tumor perfusion and provide an index of vascular complexity, making it a potentially useful addition for clinical detection of vascular normalization in anti‐angiogenic trials.
A platform‐independent method to reduce CT truncation artifacts using discriminative dictionary representations
Authors: Chen Yang , Budde Adam , Li Ke , Li Yinsheng , Hsieh Jiang , Chen Guang‐Hong
Published: January 2017

Purpose

When the scan field of view (SFOV) of a CT system is not large enough to enclose the entire cross‐section of the patient, or the patient needs to be positioned partially outside the SFOV for certain clinical applications, truncation artifacts often appear in the reconstructed CT images. Many truncation artifact correction methods perform extrapolations of the truncated projection data based on certain a priori assumptions. The purpose of this work was to develop a novel CT truncation artifact reduction method that directly operates on DICOM images.

Materials and methods

The blooming of pixel values associated with truncation was modeled using exponential decay functions, and based on this model, a discriminative dictionary was constructed to represent truncation artifacts and nonartifact image information in a mutually exclusive way. The discriminative dictionary consists of a truncation artifact subdictionary and a nonartifact subdictionary. The truncation artifact subdictionary contains 1000 atoms with different decay parameters, while the nonartifact subdictionary contains 1000 independent realizations of Gaussian white noise that are exclusive with the artifact features. By sparsely representing an artifact‐contaminated CT image with this discriminative dictionary, the image was separated into a truncation artifact‐dominated image and a complementary image with reduced truncation artifacts. The artifact‐dominated image was then subtracted from the original image with an appropriate weighting coefficient to generate the final image with reduced artifacts. This proposed method was validated via physical phantom studies and retrospective human subject studies. Quantitative image evaluation metrics including the relative root‐mean‐square error (rRMSE) and the universal image quality index (UQI) were used to quantify the performance of the algorithm.

Results

For both phantom and human subject studies, truncation artifacts at the peripheral region of the SFOV were effectively reduced, revealing soft tissue and bony structure once buried in the truncation artifacts. For the phantom study, the proposed method reduced the relative RMSE from 15% (original images) to 11%, and improved the UQI from 0.34 to 0.80.

Conclusion

A discriminative dictionary representation method was developed to mitigate CT truncation artifacts directly in the DICOM image domain. Both phantom and human subject studies demonstrated that the proposed method can effectively reduce truncation artifacts without access to projection data.
A simple and robust trajectory‐based stereotactic radiosurgery treatment
Authors: Wilson Byron , Otto Karl , Gete Ermias
Published: January 2017

Introduction

We present a Trajectory‐based Volumetric Modulated Arc Therapy (TVMAT) technique for Stereotactic Radiosurgery (SRS) that takes advantage of a modern linacs ability to modulate dose rate and move the couch dynamically. In addition, we investigate the quality of the developed TVMAT method and the dosimetric accuracy of the technique.

Methods

The main feature of the TVMAT technique is a standard beam trajectory formed by dynamic motion of the treatment couch and the linac gantry. The couch rotates slowly through 180 degrees while the gantry delivers radiation through continuous sweeps of the gantry. The number of partial arcs that constitute the trajectory can be varied between two and eight and as the number of partial arcs increases, the trajectory more finely samples 4π geometry. Along these trajectories, the multi‐leaf collimator (MLC) and dose rate are optimized through an inverse planning framework. The TVMAT method was tested on ten cranial SRS patients who were previously treated with the Dynamic Conformal Arc (DCA) technique. The plans were compared with the DCA and a four‐ arc VMAT technique with regards to dose to the OAR, dose falloff, V12Gy, and V4Gy. Validation measurements were performed using ion‐chamber and Gafchromic film. In addition, the trajectory‐log files were analyzed and compared with the treatment plan beam data.

Results

The TVMAT treatment plans were successfully delivered with a treatment time between 3–8 min which mostly depended on total cumulated dose. Ion chamber measurements had an average measured error of 1.1 ± 0.6% and a maximum value of 2.2% of the delivered dose. The 2%, 2 mm gamma pass rates for the film measurements were 96% or greater. In a preliminary comparison of ten patients who underwent SRS treatments with the DCA technique, the TVMAT and VMAT techniques were able to produce plans with comparable dose falloff and OAR doses, while achieving better dose conformality, V4Gy and V12Gy when compared to the original DCA plans. The improvement of the TVMAT plans were as follows (mean % improvement ± standard err): Conformity (10 ± 2%), V4 (20 ± 20%), V12 (27 ± 10%), volume weighted mean dose to organs at risk (13 ± 13%), homogeneity index (2 ± 2%) and falloff (4 ± 2%).

Conclusion

We have developed and validated a trajectory‐based dose delivery method which has dose distribution improvements while having a treatment time of 3–8 min. In addition, it has the potential for a simpler planning experience while maintaining an accurate delivery on the Varian Truebeam Linac.
Polymerization compounding of hemp fibers to improve the mechanical properties of linear medium density polyethylene composites
Authors: Chimeni Désiré Yomeni , Dubois Charles , Rodrigue Denis
Published: January 2017

Improved mechanical properties play an important role allowing the expansion of natural fiber composites in automotive interior parts and construction industries. Unfortunately, their hydrophilic nature leads to incompatibility with hydrophobic matrices limiting their full potential. But this can be overcome by fiber surface modification. So the objective of this work was to modify hemp fibers by an advanced process called surface‐initiated catalytic polymerization and to evaluate its effect in terms of morphological, rheological, and mechanical properties for linear medium density polyethylene (LMDPE) composites. The results showed that catalytic polymerization of hemp fibers was successful as the fibers were coated with grafted polymer chains (polyethylene). This was confirmed by an increase of the C‐H and C‐C groups by FTIR on the fibers surface, as well as the presence of an extra peak in DTG curves between 400 and 500°C. This was also confirmed by SEM pictures and density change owing to the presence of these grafted PE molecules. The composites morphology (SEM) and mechanical properties in the solid (E' and tan δ) and melt (van Gurp‐Palmen plot, complex and transient viscosity, and activation energy) state showed that, the presence of PE molecules on the surface of treated hemp fibers led to a significant improvement of the fiber‐matrix interfacial quality producing significant increases of the composite's (30% wt.) Young's modulus (8%) and tensile strength (43%) with respect to the composite based on untreated fibers, which represents a 125% and 58% increases with respect to the neat polymer. POLYM. COMPOS., 39:2860–2870, 2018. © 2017 Society of Plastics Engineers
Desulfurization performance of polydimethylsiloxane membranes by pervaporation: Effect of crosslinking agents
Authors: Liu Liangliang , Han Xiaolong , Hu Wenling , Zhao Binxia , Fan An
Published: January 2017

Polydimethylsiloxane (PDMS), as one of the typical membrane, has been widely applied in gasoline desulfurization via pervaporation. In this work, the PDMS/PVDF composite membranes were prepared by curing PDMS with three different crosslinking agents. They were 3‐Aminopropyltrimethoxylsilane (APTMS), 3‐Glycidyloxypropyltrimethoxylsilane (GPTMS), and 3‐Mercaptopropyltrimethoxylsilane (MPTMS), respectively. These PDMS/PVDF composite membranes were characterized by Fourier transform infrared (FT‐IR), X‐ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and then evaluated by static tensile test, swelling degree test and surface detach experiment. The results showed that A‐PDMS membrane had highest crosslinking density, best anti‐swelling ability and excellent combination between the separation layer and support layer. Moreover, the effect of operation temperature and the feed sulfur content on separation performance were investigated systematically. Experimental results indicated that PDMS membrane crosslinked with APTMS presented the highest enrichment factor with 3.46°C at 45°C, and PDMS membrane crosslinked with MPTMS presented the highest permeation flux with 21.19 kg/(m2·h) at 45°C. Finally, long‐term stability test showed that these PDMS membranes all have desirable stability. POLYM. ENG. SCI., 57:1127–1135, 2017. © 2017 Society of Plastics Engineers
Rheological behavior of reaction mixtures during the graft copolymerization of cassava starch with acrylic acid
Authors: Witono J.R. , Noordergraaf I.W. , Heeres H.J. , Janssen L.P.B.M.
Published: January 2017

Literature data on the rheological behavior of a reaction mixture during the graft copolymerization of acrylic acid onto gelatinized starch are scarce. Yet, such information is important for process design. In this work, continuous torque recording was found to be a suitable method to monitor the apparent viscosity. Reactions were performed in a bench scale reactor at ambient conditions with the monomer to starch ratio as the main variable. Apparent viscosity of the reaction mixture increased rapidly, which could be fitted with good accuracy with a first order exponential growth model. The maximum viscosity of 18 Pa⋅s was seen at the intermediate monomer to starch ratio of 1.0, a phenomenon that is in accordance with literature data. Starch thixotropy is influenced by the grafting of poly‐acrylic acid, until it has almost disappeared at the highest monomer to starch molar ratio of 2.0. POLYM. ENG. SCI., 57:1285–1292, 2017. © 2017 Society of Plastics Engineers
Synergistic effects of silica nanoparticles and reactive compatibilizer on the compatibilization of polystyrene/polyamide 6 blends
Authors: Zhang Xianming , Sun Menghan , Chen Wenxing
Published: January 2017

This study examines the selective dispersion of nano‐SiO2 in polystyrene (PS) and polyamide 6 (PA6) blends. With the coupling assistance of 3‐methacryloylpropyl trimethoxysilane (MPS), nano‐SiO2 surfaces are grafted with PS chains of different molecular weights (SiO2–MPS–PS) or reactive random copolymer of styrene (St) and 3‐isopropenyl‐α,α′‐dimethylbenzene isocyanate (TMI) to produce SiO2–MPS–P(St–co–TMI). The isocyanate groups of the reactive copolymer can react with the terminal group of the PA6 to form a graft copolymer, which helps in controlling the location of nano‐SiO2 between the PS and PA6 phases. Field‐emission scanning electron microscopy imaging combined with the rheological method was used to investigate the location and dispersion of nano‐SiO2, as well as the morphology of the PS/PA6 blends, at low nano‐SiO2 loading. Compared with pristine SiO2, the modified SiO2 with different chain lengths adjusted the PA6 phase with refined size and narrow size distribution because of the strong interaction with both phases. The SiO2–MPS–PS with appropriate length is the most effective. The use of nano‐SiO2 along with the reactive compatibilizer provides synergistic effects for improving the compatibilization of PS/PA6 blends. POLYM. ENG. SCI., 57:1301–1310, 2017. © 2017 Society of Plastics Engineers
Mapping the road from childhood adversity to personality disorder: The role of unresolved states of mind
Authors: Cirasola Antonella , Hillman Saul , Fonagy Peter , Chiesa Marco
Published: January 2017

Childhood adversity has been found to be an important aetiological factor in the development of personality disorder (PD) in several studies. However, the role of disorganized attachment with unresolved mental states for traumatic experiences requires further investigation. This study explores the relationship between childhood adversities, unresolved states of mind, PD diagnosis and psychiatric distress. Two hundred forty‐five adult participants, 124 from a clinical PD group and 121 non‐psychiatric controls were assessed using the Structured Clinical Interview for DSM‐IV, the Cassel Baseline Questionnaire, the Symptom Checklist‐90‐R and the Adult Attachment Interview, in order to ascertain presence of PD, childhood adversity, level of psychiatric distress and unresolved states of mind. Within the overall unresolved (U‐overall) attachment category, a distinction was made between unresolved for abuse (U‐abuse) and unresolved for loss (U‐loss). The results indicated that childhood adversity was significantly associated with unresolved states of mind, as well as with overall PD diagnosis, paranoid PD, borderline PD, avoidant PD and psychiatric distress. Mediation analyses confirmed that U‐overall and U‐loss were significant mediators between childhood adversity and PD diagnoses, but surprisingly, U‐abuse was not a significant mediator. The strength, limitations and clinical implications of the findings are discussed. Copyright © 2017 John Wiley & Sons, Ltd.
Inter‐segmental co‐ordination in sit‐to‐stand: an age cross‐sectional study
Authors: Cahill Babs M. , Carr Janet H. , Adams Roger
Published: January 2017

Background and Purpose. Being able to sit‐to‐stand (STS) effectively is an important functional skill, but there is little information available on the changes that occur with growth and maturity. This study aimed to investigate the inter‐segmental co‐ordination of STS in three different age groups (12–18 months, 4–5 years and 9–10 years). Method. The children studied wore reflective markers and were videotaped as they stood up from a heightadjustable seat that straddled a forceplate. Segmental kinematics and vertical ground reaction force were determined from the co‐ordinate and forceplate data. Results. Even at the earliest developmental stage the children had mastered the basic inter‐segmental pattern observed in adults. The youngest children, however, were not able to end the movement in quiet standing; rather they raised up on their toes or took a step forward. Performance varied both within and between subjects. Although there was a similarity in the motor pattern used by the younger subjects to that of the older subjects, developmental trends were evident on the videotapes and on examination of the kinematic and kinetic variables. Movement time, amplitude and peak angular velocity of trunk flexion increased with age. Whereas the children in the older age groups displayed a pattern of vertical ground reaction force similar to that reported for adults, the youngest children tended to reach peak force gradually, often with fluctuations. Although there were characteristic trajectories in the phase‐plane plots for each group, the overall trend was for the percentage of smooth plots representing a co‐ordinated movement, to increase with age. Conclusions. Differences in inter‐segmental co‐ordination between the ages studied may relate to the child's ability to control horizontal momentum and to balance.
Inappropriate sexual behaviours of patients towards practising physiotherapists: a study using qualitative methods
Authors: O'Sullivan Veena , Weerakoon Patricia
Published: January 2017

Background and Purpose. Recent research recognizes the occurrence of inappropriate sexual behaviour (ISB) by patients towards health professionals. The objective of this study was to explore in‐depth the clinical context and effect of incidents of ISB towards practising physiotherapists. Method. In‐depth interviews were conducted with a sub‐sample of nine physiotherapists who were part of a larger survey on ISB. Quantitative analyses of the survey responses are reported elsewhere. Interview participants were asked to describe an incident of ISB by a patient that was either perceived to be the worst or was the most recent. They were asked questions on a variety of themes, such as their relationship with the patient prior to incident, the effects of the incident, the strategies used to deal with the incident, and changes in practice as a result of the incident. Results. All interview participants reported encountering some level of ISB from patients. Although the overall frequency of these behaviours was relatively low, the range of behaviours was diverse. Regardless of the perceived severity of the incident, only four participants labelled their experience as ‘sexual harassment’. Many reported negative effects on work performance. Participants mainly used physical measures to prevent further incidents, rather than confronting the perpetrator or reporting the incident. Conclusions. The findings are discussed in the context of theory pertaining to boundaries and issues of transference and counter‐transference. This emphasized the need for effective communication skills training of both undergraduate and graduate physiotherapists in the prevention and management of ISB from patients.