bluuebunny/crossref_metadata_2025_split huggingface dataset:
A photon source model based on particle transport in a parameterized accelerator structure for Monte Carlo dose calculations
Authors: Ishizawa Yoshiki , Dobashi Suguru , Kadoya Noriyuki , Ito Kengo , Chiba Takahito , Takayama Yoshiki , Sato Kiyokazu , Takeda Ken 
Published: May 2018

PurposeAn accurate source model of a medical linear accelerator is essential for Monte Carlo (MC) dose calculations. This study aims to propose an analytical photon source model based on particle transport in parameterized accelerator structures, focusing on a more realistic determination of linac photon spectra compared to existing approaches.MethodsWe designed the primary and secondary photon sources based on the photons attenuated and scattered by a parameterized flattening filter. The primary photons were derived by attenuating bremsstrahlung photons based on the path length in the filter. Conversely, the secondary photons were derived from the decrement of the primary photons in the attenuation process. This design facilitates these sources to share the free parameters of the filter shape and be related to each other through the photon interaction in the filter. We introduced two other parameters of the primary photon source to describe the particle fluence in penumbral regions. All the parameters are optimized based on calculated dose curves in water using the pencil‐beam–based algorithm. To verify the modeling accuracy, we compared the proposed model with the phase space data (PSD) of the Varian TrueBeam 6 and 15 MV accelerators in terms of the beam characteristics and the dose distributions. The EGS5 Monte Carlo code was used to calculate the dose distributions associated with the optimized model and reference PSD in a homogeneous water phantom and a heterogeneous lung phantom. We calculated the percentage of points passing 1D and 2D gamma analysis with 1%/1 mm criteria for the dose curves and lateral dose distributions, respectively.ResultsThe optimized model accurately reproduced the spectral curves of the reference PSD both on‐ and off‐axis. The depth dose and lateral dose profiles of the optimized model also showed good agreement with those of the reference PSD. The passing rates of the 1D gamma analysis with 1%/1 mm criteria between the model and PSD were 100% for 4 × 4, 10 × 10, and 20 × 20 cm2 fields at multiple depths. For the 2D dose distributions calculated in the heterogeneous lung phantom, the 2D gamma pass rate was 100% for 6 and 15 MV beams. The model optimization time was less than 4 min.ConclusionThe proposed source model optimization process accurately produces photon fluence spectra from a linac using valid physical properties, without detailed knowledge of the geometry of the linac head, and with minimal optimization time.
Evaluating blood clot progression using magnetic particle spectroscopy
Authors: Khurshid Hafsa , Shi Yipeng , Berwin Brent L. , Weaver John B. 
Published: May 2018

PurposeTo evaluate the thrombus maturity noninvasively providing the promise of much earlier and more accurate diagnosis of diseases ranging from stroke to myocardial infarction to deep vein thrombosis.MethodsMagnetic spectroscopy of nanoparticle Brownian rotation (MSB), a form of magnetic particle spectroscopy sensitive to Brownian rotation of magnetic nanoparticles, was used for the detection and characterization of blood clots. The nanoparticles’ relaxation time was quantified by scaling the MSB spectra in frequency to match the spectra from nanoparticles in a reference state. The nanoparticles’ relaxation time, in the bound state, was used to characterize the nanoparticle binding to thrombin on the blood clot. The number of nanoparticles bound to the clot was also estimated. Both the relaxation time and the weight of bound nanoparticles were obtained for clots of several ages, reflecting different stages of development and organization. The impact of clot development was explored using functionalized nanoparticles present during clot formation.ResultsThe relaxation time of the bound nanoparticles decreases for more mature, organized clots. The number of nanoparticles able to bind the clot diminishes quantitatively with clot age. On mature clots, the nanoparticles bind the thrombin on the surface while for developing clots the nanoparticles bind several thrombin molecules or become trapped in the clot matrix during formation.ConclusionsBy estimating the magnetic nanoparticles’ relaxation time the clot age and organization can be predicted. The purposed methods are quick and minimally invasive for in vivo applications.
A novel phase‐unwrapping method by using phase‐jump detection and local surface fitting: application to Dixon water–fat MRI
Authors: Cheng Junying , Guan Jijing , Mei Yingjie , Xu Lin , Liu Xiaoyun , Feng Qianjin , Chen Wufan , Feng Yanqiu 
Published: May 2018

PurposeThis study aims to develop an accurate and robust phase‐unwrapping method that works effectively under severe noise, rapid‐varying phase, and disconnected regions for water–fat Dixon MRI.MethodsThe proposed method first segments the phase map into blocks by automatically detecting phase jumps, and then clusters the pixels near phase jumps into residual pixels. Thereafter, the proposed method sequentially performs intrablock, interblock, and residual‐pixel unwrapping using the local surface fitting approach. To address intrablock wraps, the proposed method segments each block into subblocks using the phase partition approach and then performs inter‐subblock unwrapping using a block‐growing approach. The phase derivative variance is used as the quality criterion to determine the region‐growing path of residual pixels. The performance of the proposed method was evaluated on simulation and in vivo Dixon data.ResultsThe proposed method obtained accurate phase‐unwrapping results in the simulation experiment with severe noise, rapid‐varying phase, and disconnected regions, and the mean and SD error ratio was 0.26 ± 0.07%. For 505 in vivo knee and ankle images, the total water–fat swap ratio by the proposed method was 1.78%, whereas those by phase region expanding labeler for unwrapping discrete estimates and clustering and local surface fitting were 38.42% and 7.72%, respectively.ConclusionThe proposed method achieves accurate and robust performance in phase unwrapping and can benefit phase‐related MRI applications such as Dixon water–fat separation.
Functional magnetic resonance electrical impedance tomography (fMREIT) sensitivity analysis using an active bidomain finite‐element model of neural tissue
Authors: Sadleir Rosalind J. , Fu Fanrui , Chauhan Munish 
Published: May 2018

PurposeA direct method of imaging neural activity was simulated to determine typical signal sizes.MethodsAn active bidomain finite‐element model was used to estimate approximate perturbations in MR phase data as a result of neural tissue activity, and when an external MR electrical impedance tomography imaging current was added to the region containing neural current sources.ResultsModeling‐predicted, activity‐related conductivity changes should produce measurable differential phase signals in practical MR electrical impedance tomography experiments conducted at moderate resolution at noise levels typical of high field systems. The primary dependence of MR electrical impedance tomography phase contrast on membrane conductivity changes, and not source strength, was demonstrated.ConclusionBecause the injected imaging current may also affect the level of activity in the tissue of interest, this technique can be used synergistically with neuromodulation techniques such as deep brain stimulation, to examine mechanisms of action.
Surface‐initiated atom transfer radical polymerization of a new rhodanine‐based monomer for rapid magnetic removal of Co(II) ions from aqueous solutions
Authors: Rahmaninia Arman , Mansoori Yagoub , Nasiri Farough 
Published: May 2018

The present study reports synthesis and characterization of a new acrylamide‐based monomer containing rhodanine moiety, N‐3‐amino‐thiazolidine‐4‐one‐acrylamide (ATA). Poly(ATA)‐grafted magnetite nanoparticles (poly(ATA)‐g‐MNPs) were prepared using surface‐initiated atom transfer radical polymerization of the monomer on Fe3O4 nanoparticles. The grafted nanoparticles were characterized by Fourier transform infrared analysis, scanning electron microscopy, X‐ray diffraction, and vibrating sample magnetometry. The amount of the grafted polymer was 209 mg g−1, as calculated from thermogravimetric analysis experiment. The capability of poly(ATA)‐g‐MNPs to remove Co(II) cations was shown under optimal conditions of contact time, pH, adsorbent dosage, and initial Co(II) concentration. About 86% of the Co(II) cations were removed over 7 minutes. The adsorption kinetics obeyed the pseudo–second‐order kinetic equation, and the Langmuir isotherm model best described the adsorption isotherm with a maximum adsorption capacity of 3.62 mg g−1. The thermodynamic investigation showed spontaneous nature of the adsorption process (ΔG = −2.90 kJ mol−1 at 25°C ± 1°C). In addition, the poly(ATA)‐g‐MNPs were regenerated by simply washing with an aqueous 0.1M HCl solution. The study of the reusability of the prepared magnetic sorbent revealed that the sorbent can be reused without a significant decrease in the extraction efficiency and be recovered by 95.4% after 7 cycles. These findings suggest that the grafted nanoparticles are stable and reusable adsorbent and can be potentially applied to water treatment in efficient removal of Co(II) cations.
Mandibular growth in survivors of pediatric parotid gland carcinoma treated with interstitial brachytherapy
Authors: Wu Wen‐Jie , Huang Ming‐Wei , Zhang Guo‐Hao , Zhao Dan , Zheng Lei , Yu Guang‐Yan , Zhang Jian‐Guo 
Published: May 2018

AbstractBackgroundThe aim of the study was to present long‐term results of mandibular growth in pediatric parotid gland carcinoma survivors treated with interstitial brachytherapy.ProcedureTwenty‐five survivors of pediatric parotid gland carcinoma treated with iodine‐125 seed interstitial brachytherapy were included for quantitative analysis, including three dimensional (3D) cephalometry and measurement of mandibular volume.Results3D cephalometry showed that the median fore‐and‐aft increments of the lengths of the condyle, the ramus, and the body of the mandible were 1.23, 0.19, and 1.66 mm for the affected side, respectively, and were 1.37, 1.95, and 3.42 mm for the unaffected side, respectively. The difference in increments of the ramus was statistically significant between the affected side and the unaffected side (P = 0.003; P < 0.05). Moreover, mandibular volume measurements showed that the median fore‐and‐aft increments of the volumes of the condyle, the ramus, and the body of the mandible were 290.62, 220.14, and 1706.40 mm3 for the affected side, respectively, and were 269.15, 370.40, and 1469.86 mm3 for the unaffected side, respectively. The difference in increments was statistically significant between the affected side and the unaffected side for the ramus (P = 0.005; P < 0.05) and the body (P = 0.043; P < .05).ConclusionMandibular growth was affected by interstitial brachytherapy, especially for the ramus, in pediatric parotid gland carcinoma survivors treated with interstitial brachytherapy. Nevertheless, the impact was mild in these survivors.
Psychosocial determinants of physical activity and dietary behaviors in adolescents and young adults with cancer and survivors
Authors: Diorio Caroline , Lin Meiko , Ginn Elizabeth , Ladas Elena J. 
Published: May 2018

AbstractBackgroundSurvivors of childhood cancer are at increased risk of lifestyle influenced health issues. We sought to understand the association between stages of change (SOC) and psychosocial variables related to modifiable health behaviors: physical activity (PA), dietary fat intake, and intake of fruits and vegetables among adolescents and young adults at different phases of cancer therapy.MethodsWe conducted an exploratory cross‐sectional survey of adolescents and young adults currently being treated for cancer or who are survivors of childhood cancer. We evaluated SOC and several psychosocial variables using the previously validated Patient‐Centered Assessment and Counseling for Exercise (PACE+): Physical Activity and Diet Surveys for Adolescents tool. Current dietary behaviors were evaluated with 24 hr diet recall.ResultsOne hundred and eighteen patients participated in the survey. SOC did not vary by phase of treatment. Ethnicity and body mass index were strongly associated with SOC for PA, but not for dietary behaviors. There was a significant association between SOC and self‐efficacy, knowledge of strategies, and family or friend support for PA, dietary fat, and fruits and vegetables. Higher self‐efficacy and family support were significant variables impacting SOC and participants’ reported intake of fruits and vegetables servings.ConclusionWe demonstrate that SOC for the investigated behaviors did not change based on phase of treatment, supporting the initiation of lifestyle interventions early on in treatment. We identify several psychosocial variables that may act as important targets for future lifestyle interventions aimed to improve dietary and exercise behaviors in adolescents and young adults with cancer and survivors.
Gemcitabine/nab‐paclitaxel for pediatric relapsed/refractory sarcomas
Authors: Metts Jonathan L. , Alazraki Adina L. , Clark Dana , Amankwah Ernest K. , Wasilewski‐Masker Karen J. , George Bradley A. , Olson Thomas A. , Cash Thomas 
Published: May 2018

AbstractBackgroundPediatric patients with relapsed/refractory sarcomas have poor outcomes and need novel therapies that provide disease control while maintaining an acceptable quality of life. The activity and toxicity of gemcitabine and nab‐paclitaxel in combination has not been reported in pediatrics.ProcedureWe reviewed the records of fifteen relapsed/refractory patients and one treatment‐naïve patient who received gemcitabine/nab‐paclitaxel at our institution.ResultsSixteen patients (median age 13.5 years, range 3–19 years) received 53 cycles of gemcitabine/nab‐paclitaxel. Twenty‐nine cycles (55%) resulted in ≥Grade 3 toxicity, with nonhematologic Grade ≥3 toxicities occurring in only eight of 53 cycles (15%). Patients received red blood cell and platelet transfusions in 23% and 4% of cycles, respectively. Grade ≥3 infectious toxicities occurred in 4% of cycles. Of 14 patients with measurable disease, there were no complete responses (CR), one partial response (PR; 7%), and six patients (43%) with stable disease (SD; median SD: 4.5 months, range: 2–19 months). In total, 31% of the patients derived clinical benefit (CR + PR + SD ≥ 4 months). Median time to progression was 72 days with a 4‐month progression‐free survival of 31% ± 12% and 1‐year overall survival of 19% ± 10%. With a median follow‐up for all 16 patients of 21 months from the first treatment with gemcitabine/nab‐paclitaxel, one (6%) remains alive with disease.ConclusionsGemcitabine/nab‐paclitaxel is a relatively safe regimen with mainly hematologic toxicities. It offers a well‐tolerated, palliative option providing clinical benefit in a subset of patients. A phase I trial of this combination is underway.
Myeloid lineage switch following chimeric antigen receptor T‐cell therapy in a patient with TCF3‐ZNF384 fusion‐positive B‐lymphoblastic leukemia
Authors: Oberley Matthew J. , Gaynon Paul S. , Bhojwani Deepa , Pulsipher Michael A. , Gardner Rebecca A. , Hiemenz Matthew C. , Ji Jianling , Han Jennifer , O'Gorman Maurice R.G. , Wayne Alan S. , Raca Gordana 
Published: May 2018

AbstractA pediatric patient diagnosed initially with B‐lymphoblastic leukemia (B‐ALL) relapsed with lineage switch to acute myeloid leukemia (AML) after chimeric antigen receptor T‐cell (CAR‐T) therapy and hematopoietic stem cell transplant. A TCF3‐ZNF384 fusion was identified at diagnosis, persisted through B‐ALL relapse, and was also present in the AML relapse cell population. ZNF384‐rearrangements define a molecular subtype of B‐ALL characterized by a pro‐B‐cell immunophenotype; furthermore, ZNF384‐rearrangements are prevalent in mixed‐phenotype acute leukemias. Lineage switch following CAR‐T therapy has been described in patients with KMT2A (mixed lineage leukemia) rearrangements, but not previously in any patient with ZNF384 fusion.
Theoretical model and simulation of carrier heating with effects of nonequilibrium hot phonons in semiconductor photovoltaic devices
Authors: Tsai Chin‐Yi 
Published: May 2018

AbstractA theoretical model and its rate equations of carrier number and energy densities are proposed and presented for calculating carrier heating in semiconductor photovoltaic devices. The rate equation for carrier number density is the Shockley‐Queisser theoretical model, while the rate equation for carrier energy density includes the carrier interband energy relaxation via radiative recombination and the intraband energy relaxation via the interactions between carriers and polar longitudinal optical phonons. The carrier intraband energy relaxation is calculated by incorporating the effects of nonequilibrium hot phonons and the Thomas‐Fermi static screening. This model and its rate equations are employed for numerical simulations of the magnitude of carrier heating and its effects on the current‐voltage relations of bulk GaAs solar cells under different concentration ratios and with different widths of the active region. The simulation results demonstrate that carrier temperature in general heats up to 400 to 900 K at short‐circuit operating condition. This carrier heating cools down to lattice temperature when the device approaches its open‐circuit point. Based on these numerical results, effects of carrier heating on the performance of conventional solar cells and also their implications for the design of hot‐carrier solar cells will be discussed.
NeuroCog FX study: A multicenter cohort study on cognitive dysfunction in patients with early breast cancer
Authors: Rick Oliver , Reuß‐Borst Monika , Dauelsberg Timm , Hass Holger G. , König Volker , Caspari Reiner , Götz‐Keil Gabriele , Pfitzner Jürgen , Kerschgens Christa , Fliessbach Klaus , Hoppe Christian 
Published: May 2018

AbstractObjectiveComplaints about cognitive dysfunction (CD) reportedly persist in approximately one third of breast cancer patients, but the nature of CD and possible risk factors are unknown.MethodsA cross‐sectional, multicenter study was set up at 9 German oncological rehabilitation centers. Objective cognitive performance was assessed by the NeuroCog FX test, a short computerized screening (duration <30 minutes) which assesses working memory, alertness, verbal/figural memory, and language/executive. Patients' test performance was correlated with treatment factors (chemo‐, radiotherapy), subjective performance (FEDA), depression (PHQ‐9), quality of life (EORTC QLQ‐30), and clinical characteristics.ResultsFrom February 2013 to December 2014, a clinically homogenous sample of 476 patients was recruited (early tumor stage [T0‐T2]: 93%; node‐negative: 67%; chemotherapy: 61%; radiotherapy: 84%). NeuroCog FX could be administered in 439 patients (92%; median age: 50 [24‐62] years). Patients showed decreased performance in attentional‐executive functions (but not verbal/figural memory) and a 3‐fold rate of CD in terms of below average performance in at least 1 cognitive domain (42%). Approximately 40% of the patients also reported subjective cognitive impairment (FEDA). No therapy‐specific effect on test performance was obtained in the NeuroCog FX test.ConclusionsBreast cancer survivors showed objective attentional‐executive and subjective cognitive impairments. No therapy‐specific adverse side effect on objective cognitive performance was found. Depression strongly contributed to objective and subjective cognitive complaints and reduced quality of life.
The analysis of thermal and anodic oxide layers on selected biocompatible titanium alloys
Authors: Krčil Jan , Rafaj Zdeněk , Mára Vladimír , Krum Stanislav , Starý Vladimír , Nehasil Václav , Sobotová Jana 
Published: May 2018

In the case of titanium alloys, the oxide layers on their surfaces strongly influence biocompatibility and corrosion resistance. To improve these characteristics, properties of oxide layers prepared by various methods on different base materials were examined. In this work, samples of widely used biomaterials, CP titanium grade 2 and alloy Ti6Al4V, were compared with recently developed β‐titanium alloy Ti‐39 wt% Nb. On the samples from these materials, the thermal (600°C/8 hr/atmospheric air) and anodic (1‐M H2SO4/100 V/1 hr) oxide layers were prepared. The change of surface color was observed. The surface topography of oxidized samples was observed using scanning electron microscopy. The thickness of oxide layers was measured and observed on the cross‐sectional samples. The further analysis of oxide layers surfaces was conducted using X‐ray photoelectron spectroscopy and atomic force microscopy. The growth of hydroxyapatite for further comparison of oxide layers was realized in Hank' balanced salt solution.
Multifunctional Logic Applications of a Single Molecule: A Molecular Photo‐Switch Performing as Simple and Complex Gates, Memory Element, and a Molecular Keypad Lock
Authors: Karar Monaj , Shit Pradip , Halder Basudeb , Mallick Arabinda , Majumdar Tapas 
Published: May 2018

AbstractCarbazole (CZ) can act as a photo‐switch leading to a multifunctional logic system when triggered by fluoride (F–) ions, H2O and light, through efficient interaction of the pyrrole unit with the anions. Here we are reporting a unimolecular platform of CZ (and case specific CZ‐F–) that can be configured as NOT, YES, complimentary IMPLICATION and INHIBIT, a new complex logic gate performing IF‐THEN and NOT operations and a memory element with cyclic “Erase‐Read‐Write‐Read” ability with feedback loop mechanism. The fluorescence responses of the CZ system also have been exploited to design a potential highly secured molecular keypad lock operating with a purely opto‐chemical password composed with optical and chemical input keys. The system displays the applications of light responsive molecules as multifunctional, reconfigurable molecular logic devices that may lead towards true molecular information processing units.
A Ce(III)‐Based Coordination Polymer as Sorbent for the Removal of Pb2+ and Cd2+ Ions from Water
Authors: Abbasi Alireza , Amirshekari Shokoufeh , Najafi Mahnaz , Shahbaazi Hamidreza 
Published: May 2018

AbstractA two‐dimensional coordination polymer based on Ce(III), [Ce2(μ3‐atp)2(μ2‐atp)(H2O)8].4H2O (1) (atp=2‐aminoterephthalate), was synthesized by solvent diffusion approach. The coordination polymer was characterized by X‐ray single crystal diffraction, powder X‐ray diffraction (PXRD), thermal analysis (TGA) and Fourier transformation infrared (FT‐IR) spectroscopy. Coordination polymer 1 was employed as sorbent for the removal of Cd2+ and Pb2+ from water under room conditions. Compound 1 displayed the same affinity for the adsorption of the metal ions and could be reused for the adsorption process after a simple treatment.