bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle‐in‐cell/Monte Carlo simulation of electron and ion currents to cylindrical Langmuir probe
Authors: Zikán Petr , Farkaš Kristián , Trunec David , Jánský Jaroslav , Bonaventura Zdeněk
Published: November 2018

Electron and ion currents to a cylindrical Langmuir (electrostatic) probe were calculated using the particle‐in‐cell/Monte Carlo (PIC/MC) self‐consistent simulation for a neutral gas in the pressure range 2–3,000 Pa. The simulation enables us to calculate the probe currents even at high neutral gas pressures when the collisions of collected charged particles with neutral gas particles near the probe are important. The main aim of this paper is the calculation of probe currents at such high gas pressures and the comparison of the results with experimentally measured probe currents. Simulations were performed for two cases: (a) probes with varying radii in a non‐thermal plasma with high electron temperature at low neutral gas pressure of 2 Pa (in order to verify the correctness of our simulations), and (b) probe with the radius of 10 μm in the afterglow plasma with low electron temperature and a higher neutral gas pressure (up to 3,000 Pa). The electron probe currents obtained in case (a) show good agreement with those predicted by the orbital motion limited current (OMLC) theory for probes with radii up to 100 μm for the given plasma conditions. At larger probe radii and/or at higher probe voltages, the OMLC theory incorrectly predicts too high an electron probe current for the plasma parameters studied. Additionally, a formula describing the spatial dependence of the electron density in the presheath in the collisionless case is derived. The simulation at higher neutral gas pressures, i.e. case (b), shows a decrease of the electron probe current with increasing gas pressure and the creation of a large presheath around the probe. The simulated electron probe currents are compared with those of measurements by other authors, and the differences are discussed.
Isolation and Characterization of a Monoprotonated Hydroporphyrin
Authors: Arkhypchuk Anna I. , Orthaber Andreas , Kovacs Daniel , Borbas K. Eszter
Published: November 2018

A simple protocol for the controlled preparation of mono‐ and diprotonated hydroporphyrins (chlorins) is presented. The chlorins carried 10‐aryl groups with electron‐neutral (phenyl), electron‐donating (p‐OMe‐C6H4) or electron‐withdrawing (pentafluorophenyl) substituents. The protonation reactions were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first (4.8–5.3) and second pKa's (1.7–0.5). Both mono‐ and diprotonated species were fully characterized by 1H NMR spectroscopy, which, in combination with theoretical studies, showed that these macrocycles were significantly distorted in solution. A 10‐phenyl‐substituted monoprotonated chlorin was characterized by X‐ray crystallography. This is the first structurally characterized hydroporphyrin monocation, and the first crystal structure of a sterically unencumbered singly protonated tetrapyrrole. The photostabilities of the mono‐ and diprotonated 10‐phenylchlorins were measured upon irradiation into their Soret bands; protonation yielded increased photostabilities.
Nutritional value assessment of umufumba: A Rwandan wild edible plant Mondia whytei (Hook. F)
Authors: Janvier Habinshuti , Muhizi Théoneste , Ndayambaje Jean Bernard , Akenga Teresa Ayuko
Published: November 2018

This study reports findings on the macro‐ and micronutrient content of the root bark of Mondia whytei Skeels (Hook. F) (Asclepiadaceae), from five Rwandan different localities Northern part, and the nutritional content was found to vary locality of the plant. Vitamins were analyzed using high‐performance liquid chromatography (HPLC). The vitamins analyzed included β‐carotene (fat soluble), niacin, riboflavin, and thiamine (water soluble) whose content was found to range from 4.4 to 73.5 μg/g dry matter. Atomic absorption spectrophotometry (AAS) was used to analyze calcium, iron, copper, manganese, magnesium, zinc, cadmium, and lead, whereas flame emission spectrophotometry (FES) was used for the determination of sodium and potassium. The highest mineral (mg/g of dry matter) was K (11.34–32.05), while the lowest was Pb (0.03–0.06). Mean total protein content was determined using the combustion method, and the mean percentage range was 4.7%–15.4%. The sugars (fructose, glucose, sucrose, and xylose) were analyzed by HPLC. There were significant differences (2.5–132.2 mg/g) in the free sugar contents. The results obtained in this study indicate that Mondia whytei Skeels (Hook. F) is rich in nutrients and can be developed for use as a food supplement since the nutrient contents are within the ranges recommended by FAO and WHO.
Integrity of Cajal–Retzius cells in thereeler‐mouse hippocampus
Authors: Anstötz Max , Karsak Meliha , Rune Gabriele M.
Published: November 2018

Cajal–Retzius (CR) cells are early‐born glutamatergic neurons that are primarily known as the early main source of the signal protein Reelin. In thereelermutant, the absence of Reelin causes severe defects in the radial migration of neurons, resulting in abnormal cortical layering. To date, the exact morphological properties of CR‐cells independent of Reelin are unknown. With this in view, we studied the ontogenesis, density, and distribution of CR‐cells inreelermice that were cross‐bred with a CXCR4‐EGFP reporter mouse line, thus enabling us to clearly identify CR‐cells positions in the disorganized hippocampus of thereelermouse. As evidenced by morphological analysis, differences were found regarding CR‐cell distribution and density: generally, we found fewer CR‐cells in the developing and adultreelerhippocampus as compared to the hippocampus of wild‐type animals (WT); however, inreelermice, CR‐cells were much more closely associated to the hippocampal fissure (HF), resulting in relatively higher local CR‐cell densities. This higher local cell density was accompanied by stronger immunoreactivity of the CXCR4 ligand, stroma‐derived factor‐1 (SDF‐1) that is known to regulate CR‐cell positioning. Importantly, confocal microscopy indicates an integration of CR‐cells into the developing and adult hippocampal network inreelermice, raising evidence that network integration of CR‐cells might be independent of Reelin.
DYNAMIC‐MATURATIONAL MODEL OF ATTACHMENT AND ADAPTATION VERSUS ABC+D ASSESSMENTS OF ATTACHMENT IN CHILD PROTECTION AND TREATMENT: REPLY TO VAN IJZENDOORN, BAKERMANS, STEELE, & GRANQVIST (2018)
Authors: Crittenden Patricia M. , Spieker Susan J.
Published: November 2018

In this brief response, we commend the commentary authors for joining a dialogue about the future of individual differences in attachment both around person‐specific forensic and clinical issues also around working together to develop theory and coding practices. We point to several areas of explicit and implicit agreement and discuss several misunderstandings. We close with a proposal for future work together, possibly using the only set of video‐recorded Strange Situations classified by Mary Ainsworth as a starting point from which we can explore alternative means of extending and expanding her work.
The story of PKC: A discovery marked by unexpected twists and turns
Authors: Kikkawa Ushio
Published: November 2018

Protein kinase C (PKC) is activated by 1,2‐diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol phospholipids, although it was not found by screening for a 1,2‐diacylglycerol‐dependent enzyme. PKC is also a receptor for the tumor‐promoting phorbol esters, but it was not identified by its property of binding phorbol esters, either. Instead, the discovery and characterization of PKC, now known to comprise a family with multiple isoforms, was through a circuitous voyage filled with unexpected twists and turns. This review summarizes the discovery and the initial experiments of PKC as a historical perspective of the enzyme family in the context of the progress in the studies on protein phosphorylation. © 2018 IUBMB Life, 71(6):697–705, 2019
In vitro neurosphere formation correlates with poor survival in glioma
Authors: C. Jayakrishnan Padmakrishnan , H. Venkat Easwer , M. Ramachandran Girish , K. Kesavapisharady Krishna , N. Nair Suresh , Bharathan Bhavya , Radhakrishnan Neelima , Gopala Srinivas
Published: November 2018

Sphere formation is an indicator of tumor aggressiveness independent of the tumor grade; however, its relation to progression‐free survival (PFS) is less known. This study was designed to assess the neurosphere forming ability among low grade glioma (LGG) and high‐grade glioma (HGG), its stem cell marker expression, and correlation to PFS. Tumor samples of 140 patients, including (LGG; n = 67) and (HGG; n = 73) were analyzed. We used sphere forming assay, immunofluorescence, and immunohistochemistry to characterize the tumors. Our study shows that, irrespective of the pathological sub type, both LGG and HGG formed neurospheres in vitro under conventional sphere forming conditions. However, the number of neurospheres formed from tumor tissues were significantly higher in HGG compared to LGG (P < 0.0001). Different grades of glioma were further characterized for the expression of stem cell marker proteins and lineage markers. When neurospheres were analyzed, CD133 positive cells were identified in addition to CD15 and nestin positive cells in both LGG and HGG. When these neurospheres were subjected to differentiation, cells positive for GFAP and β‐tubulin III were observed. Expression of stem cell markers and β‐tubulin III were prominent in HGG compared to LGG, whereas GFAP expression was higher in LGG than in HGG. Kaplan–Meier survival analysis demonstrated that neurosphere forming ability was significantly associated with shorter PFS (P < 0.05) in both LGG and HGG. Our results supports earlier studies that neurosphere formation may serve as a definitive indicator of stem cell population within the tumor and thus a better predictor of PFS than the tumor grades alone. © 2018 IUBMB Life, 71(1):244–253, 2019
StruggleIs Not a Bad Word: Misconceptions and Recommendations About Readers Struggling With Difficult Texts
Authors: Lupo Sarah M. , Strong John Z. , Conradi Smith Kristin
Published: November 2018

Many teachers feel that students should not struggle with text; instead, they should read easier texts in order to learn from them and make adequate growth in reading. In turn, teachers might use easier or leveled texts as a solution or a graphic novel or multimodal version to differentiate text reading and to motivate and engage reluctant readers. The authors refute commonly held assumptions or misconceptions and offer alternative recommendations to improve students’ ability to learn from text and develop reading comprehension. The authors also suggest that teachers should embrace the struggle by providing supportive opportunities for all students to engage with challenging texts with appropriate instructional supports. Comprehension scaffolds include addressing adolescent readers’ knowledge and vocabulary needs, engaging readers in discussion about the text, and motivating and engaging readers with the topic and text throughout the reading experience.
ADAMTS13 kinetics after therapeutic plasma exchange and plasma infusion in patients with Upshaw‐Schulman syndrome
Authors: Kovarova Petra , Hrdlickova Radomira , Blahutova Sarka , Cermakova Zuzana
Published: November 2018

Background

Hereditary thrombotic thrombocytopenic purpura, also called Upshaw‐Schulman syndrome (USS), is a rare disease caused by genetic mutations in the ADAMTS13 gene, which severely decrease the activity of ADAMTS13, a metalloprotease that cleaves von Willebrand factor multimers (VWF). Genotypically identical patients can show great phenotypic diversity.

Objectives

Comparison of selected laboratory parameters and ADAMTS13 pharmacokinetics among patients with USS was performed.

Patients/methods

Six patients with USS on prophylactic plasma therapy have been reviewed, retrospectively. Blood counts, lactate dehydrogenase (LDH), and ADAMTS13 activity at various time‐points before and after different treatment cycles were evaluated.

Results

ADAMTS13 recovery and pharmacokinetics were affected by treatment modality, and also reflected the patients' comorbidities and their current physiological and clinical condition.

Conclusions

Our present findings support a multifactorial contribution to treatment efficacy, and confirm the importance of adaptability and individualization of USS therapy. Therapeutic plasma exchange even in hereditary TTP is an option that can in some patients prolong intervals between plasma administration.
A simple model of planar membrane: An integral equation investigation
Authors: Yagi Tomoaki , Sato Hirofumi
Published: November 2018

A simple model of a lipid membrane, a binary mixture of saturated lipids and unsaturated lipids, was studied using an integral equation theory. The planar membrane is modeled as mixture of linear and bent molecules in two‐dimensional space, and site–site radial distribution function, Kirkwood–Buff (KB) integral and related quantities were computed over the whole range of the molar fraction to understand their mixing behavior. We found that a close packing of linear molecules is enhanced as the fraction of bent molecules increases, but a long range correlation between the linear molecules is weakened. A high concentration of linear molecules promotes the demixing of linear molecules and bent molecules, and enhances the long range correlation between molecules. This implies that, the higher the concentration of linear molecules, the larger clusters tend to be formed. © 2018 Wiley Periodicals, Inc.
Accuracy and reliability of bedside thoracic ultrasound in detecting pulmonary pathology in a heterogeneous pediatric intensive care unit population
Authors: Tripathi Sandeep , Ganatra Hammad , Martinez Edmundo , Mannaa Mohannad , Peters Joe
Published: November 2018

Purpose

This study was designed to access sensitivity and specificity of detection of lung abnormalities by the ultrasound (US) done by PICU providers of varying levels of experience compared to CXR and to assess the inter‐rater reliability in the interpretation of the USG findings.

Methods

Up to three US examinations were performed on patients meeting eligibility criteria. US examinations were reported by the operator and remotely by an expert reader. Both operator and readers interpretation were correlated with CXR read by an independent pulmonologist.

Results

One hundred and thirty‐five US examinations were performed on 91 patients over 9 months. Overall agreement between the operator and reader of the US was 0.53 (0.38‐0.68). The agreement was highest with an expert‐expert pair (0.75) and lowest with a novice‐expert pair (0.27). Sensitivity and specificity of thoracic US to detect pulmonary abnormalities showed a high sensitivity by the operator (82.5%) compared to the reader (63.4%). Specificity was 25% and 42.8%, respectively. US was overall highly sensitive to detect pneumonia (96.4%) with a 100% PPV, but only modest for bronchiolitis.

Conclusions

Lungs US is a rapid and sensitive bedside tool to assess lung consolidation in children in ICU. It, however, has low negative predictive values, and negative US examinations cannot rule out lung pathology.
Correlation between tumor glucose metabolism and multiparametric functional MRI (IVIM and R2*) metrics in cervical carcinoma: Evidence from integrated 18F‐FDG PET/MR
Authors: Li‐Ou Zhang , Hong‐Zan Sun , Xiao‐Xi Bai , Zhong‐Wei Chen , Zai‐Ming Lu , Jun Xin , Qi‐Yong Guo
Published: November 2018

Background

Multiparameter, multimodality 18F‐FDG PET/MRI holds great potential for the diagnosis of cervical cancer based on the correlation between tumor glucose metabolism and imaging parameters.

Purpose

To characterize the heterogeneity of tumor glucose metabolism by evaluating the correlation between 18F‐FDG uptake parameters and multiparametric functional MRI metrics in cervical carcinoma.

Study Type

Retrospective.

Population

Fifty‐four patients with cervical carcinoma.

Field Strength/Sequence

Hybrid PET/MR (3T), multi‐b DWI, and R2* mapping.

Assessment

The maximum and mean standardized uptake values (SUVmax and SUVmean, respectively) from PET and functional MRI metrics (D, D*, f, and R2*) were obtained. Cervical carcinoma tissues also underwent HIF‐1α, VEGF, and GLUT‐1 immunohistochemical staining.

Statistical Tests

Single‐factor Spearman rank and Pearson correlation analysis and multiple linear regression (MLR) analysis were applied.

Results

R2*, D, and f have different degrees of correlation (moderate, weak, moderately strong correlation, respectively) with SUVmax and SUVmean (r = 0.530 and 0.527, and P < 0.001 for R2*; r = –0.292 and –0.291, and P < 0.05 for D; r = 0.539 and 0.520, and P < 0.001 for f, respectively). Immunohistochemical staining showed that HIF‐1α expression has a moderate degree of correlation with R2* (r = 0.491; P < 0.001); GLUT‐1 expression was significantly correlated with SUVmax and SUVmean (r = 0.633 and 0.622; P < 0.001), and VEGF expression had a moderately strong correlation with f (r = 0.457; P = 0.001). If SUVmax is the dependent variable, MLR yields an R‐squared value after adjustment (adjusted R‐squared) = 0.358, and F = 10.833 (P < 0.001), and the fitting linear equation is Y (SUVmax) = 9.184 + 0.161X1 (R2*)+50.343X2 (f)‐4.780 (D). Otherwise, MLR yields the adjusted R‐squared = 0.342, and F = 10.187 (P < 0.001), and the linear regression equation is Y (SUVmean) = 5.925 + 0.102X1 (R2*)+28.029X2 (f)‐2.907X3 (D).

Data Conclusion

The functional MRI sequence parameters R2*, f, and D can provide information on the hypoxic condition, blood perfusion, and molecular diffusion of the tumor. 18F‐FDG PET/MR multi‐imaging technique can be adopted to evaluate the heterogeneity of glucose metabolism in cervical carcinoma.

Level of Evidence: 3

Technical Efficacy: Stage 3

J. Magn. Reson. Imaging 2019;49:1704–1712.
Outcome of early dental implant placement versus other dental implant placement protocols: A systematic review and meta‐analysis
Authors: Bassir Seyed Hossein , El Kholy Karim , Chen Chia‐Yu , Lee Kyu Ha , Intini Giuseppe
Published: November 2018

Background

The aim of this systematic review and meta‐analysis was to compare the clinical efficacy of the early dental implant placement protocol with immediate and delayed dental implant placement protocols.

Methods

An electronic and manual search of literature was made to identify clinical studies comparing early implant placement with immediate or delayed placement. Data from the included studies were pooled and quantitative analyses were performed for the implant outcomes reported as the number of failed implants (primary outcome variable) and for changes in peri‐implant marginal bone level, peri‐implant probing depth, and peri‐implant soft tissue level (secondary outcome variables).

Results

Twelve studies met the inclusion criteria. Significant difference in risk of implant failure was found neither between the early and immediate placement protocols (risk difference = −0.018; 95% confidence interval [CI] = −0.06, 0.025; P = 0.416) nor between early and delayed placement protocols (risk difference = −0.008; 95% CI = –0.044, 0.028; P = 0.670). Pooled data of changes in peri‐implant marginal bone level demonstrated significantly less marginal bone loss for implants placed using the early placement protocol compared with those placed in fresh extraction sockets (P = 0.001; weighted mean difference = −0.14 mm; 95% CI = −0.22, −0.05). No significant differences were found between the protocols for the other variables.

Conclusions

The available evidence supports the clinical efficacy of the early implant placement protocol. Present findings indicate that the early implant placement protocol results in implant outcomes similar to immediate and delayed placement protocols and a superior stability of peri‐implant hard tissue compared with immediate implant placement.
The dependence of synchrony on timescale and geography in freshwater plankton
Authors: Anderson Thomas L. , Sheppard Lawrence W. , Walter Jonathan A. , Hendricks Susan P. , Levine Todd D. , White David S. , Reuman Daniel C.
Published: November 2018

Spatial synchrony is defined by related fluctuations through time in population abundances measured at different locations. The degree of relatedness typically declines with increasing distance between sampling locations. Standard approaches for assessing synchrony assume isotropy in space and uniformity across timescales of analysis, but it is now known that spatial variability and timescale structure in population dynamics are common features. We tested for spatial and timescale structure in the patterns of synchrony of freshwater plankton in Kentucky Lake, U.S.A. We also evaluated whether different mechanisms may drive synchrony and its spatial structure on different timescales. Using wavelet techniques and matrix regression, we analyzed phytoplankton biomass and abundances of seven zooplankton taxa at 16 locations sampled from 1990 to 2015. We found that zooplankton abundances and phytoplankton biomass exhibited synchrony at multiple timescales. Timescale structure in the potential mechanisms of synchrony was revealed primarily through networks of relationships among zooplankton taxa, which differed by timescale. We found substantial interspecific variability in geographic structures of synchrony and their causes: all mechanisms we considered strongly explained geographic structure in synchrony for at least one species, while Euclidean distance between sampling locations was generally less well supported than more mechanistic explanations. Geographic structure in synchrony and its underlying mechanisms also depended on timescale for a minority of the taxa tested. Overall, our results show substantial and complex but interpretable variation in structures of synchrony across three variables: space, timescale, and taxon. It seems likely these aspects of synchrony are important general features of freshwater systems.
Sustained Protein Release from a Core‐Shell Drug Carrier System Comprised of Mesoporous Nanoparticles and an Injectable Hydrogel
Authors: Manavitehrani Iman , Fathi Ali , Schindeler Aaron , Dehghani Fariba
Published: November 2018

The manufacture of a biocompatible carrier for controlled delivery of bioactive compounds is described. This carrier is composed of a mesoporous silica nanoparticle as core that is homogenously distributed in an injectable hydrogel. For the synthesis of nanoparticles, a one step sol‐gel method is developed to produce pores with the range of 100 nm. BMP2 and Fluorescein‐conjugated bovine serum albumin is used as proteinaceous agents for measuring release, and is loaded into mesoporous silica nanoparticles at the optimum conditions of 48 h incubation period using 1:10 ratio of protein to nanoparticles. The release of proteins from either mesoporous nanoparticles or hydrogel individually involves a burst release stage, however the release from the core/shell carrier designed in this study follows a zero order kinetic. In summary, this biomaterial may be favorable for delivery of bioactive compounds such as BMP2 for a range of applications including bone tissue regeneration.
Extremely Soft, Conductive, and Transparent Ionic Gels by 3D Optical Printing
Authors: Ahmed Kumkum , Naga Naofumi , Kawakami Masaru , Furukawa Hidemitsu
Published: November 2018

A series of 3D printable multifunctional ionic gels (IGs) are developed incorporating ionic liquid (IL) in the thiol–ene network of thiol‐based end‐crosslinker and acrylate monomers. The resulted gels, termed as thiol‐ionic gels (T‐IGs), are highly transparent and very soft with IL content of 70–85 wt%. The mechanical and conductive properties of the T‐IGs are found to be largely dependent on the IL content, end‐crosslinker functionalities, and chain‐length of monomers. Progression of ionic conductivity is observed with an increase in IL content and conductivity as high as 5.40 mS cm−1is attained for longer acrylate group containing T‐IGs at room temperature, while further increase is observed at elevated temperature. T‐IGs in all systems are found to exhibit superior thermal stability. Three‐dimensional fabrication of these functional T‐IGs is achieved by optical 3D printing process with microscale resolution in facile steps.
Functional Macromolecular Systems: Kinetic Pathways to Obtain Tailored Structures
Authors: Abetz Volker , Kremer Kurt , Müller Marcus , Reiter Günter
Published: November 2018

This article aims to stimulate research on non‐equilibrium macromolecular systems, as nowadays a large toolbox to synthesize tailored macromolecules is available. A large variety of characterization methods covering a broad spectrum of length and timescales allows researchers to follow and also manipulate macromolecular systems on their paths toward equilibrium. These possibilities are paralleled by the development of new concepts of the statistical physics of non‐equilibrium phenomena in macromolecular systems as well as new models and algorithms for computer simulation.
Multilayered Polyurethane–Hydroxyapatite Composite for Meniscus Replacements
Authors: Song Eun‐Ho , Seong Yun‐Jeong , Kim Jinyoung , Kim Hyoun‐Ee , Jeong Seol‐Ha
Published: November 2018

Inspired by the anisotropic structure of natural menisci, porous and densified layers of glycerol phosphate (gp)‐conjugated polyurethane (PU) and hydroxyapatite (HA), abbreviated PUH, are alternately stacked to fabricate a biomimetic multilayered scaffold. Densification is used to better match the mechanical properties of the composites to those of natural menisci for load‐bearing applications. The porosity is easily controlled (30%, 10%, and 7%) during the densification process by adjusting the applied heat and pressure. The strength and elastic modulus of the densified PUH are significantly higher than those of the porous PUH because HA is trapped as fillers inside the densified PU matrix. Multi‐layered PUH is successfully fabricated after stacking the densified and porous layers alternately. And each layer is highly attached, resulting in good interfacial stability. In addition, the scaffold is stiff along thex‐ andy‐directions and more flexible along thez‐axis (the stacking direction), as designed.
California voters this week consider using mental health funds for housing
Authors: Enos Gary
Published: November 2018

Backers of California's voter‐author‐ized Mental Health Services Act are going back to the ballot this year in the hope of fulfilling what they consider an unrealized aim of the Proposition 63 initiative that voters approved in 2004.
Report sheds light on economic burden of veterans with TRD
Authors: Canady Valerie A.
Published: November 2018

Despite veterans having a higher disposition toward depression, there is limited evidence on the burden of treatment‐resistant depression (TRD) in this population, say researchers of a new study addressing this issue. The results underscore the critical importance of more research and, consequently, the importance for novel treatment for veterans with TRD, they said.
Optimized Diffusion‐Weighting Gradient Waveform Design (ODGD) formulation for motion compensation and concomitant gradient nulling
Authors: Peña‐Nogales Óscar , Zhang Yuxin , Wang Xiaoke , de Luis‐Garcia Rodrigo , Aja‐Fernández Santiago , Holmes James H. , Hernando Diego
Published: November 2018

Purpose

To present a novel Optimized Diffusion‐weighting Gradient waveform Design (ODGD) method for the design of minimum echo time (TE), bulk motion‐compensated, and concomitant gradient (CG)‐nulling waveforms for diffusion MRI.

Methods

ODGD motion‐compensated waveforms were designed for various moment‐nullings Mn (n = 0, 1, 2), for a range of b‐values, and spatial resolutions, both without (ODGD‐Mn) and with CG‐nulling (ODGD‐Mn‐CG). Phantom and in‐vivo (brain and liver) experiments were conducted with various ODGD waveforms to compare motion robustness, signal‐to‐noise ratio (SNR), and apparent diffusion coefficient (ADC) maps with state‐of‐the‐art waveforms.

Results

ODGD‐Mn and ODGD‐Mn‐CG waveforms reduced the TE of state‐of‐the‐art waveforms. This TE reduction resulted in significantly higher SNR (P < 0.05) in both phantom and in‐vivo experiments. ODGD‐M1 improved the SNR of BIPOLAR (42.8 ± 5.3 vs. 32.9 ± 3.3) in the brain, and ODGD‐M2 the SNR of motion‐compensated (MOCO) and Convex Optimized Diffusion Encoding‐M2 (CODE‐M2) (12.3 ± 3.6 vs. 9.7 ± 2.9 and 10.2 ± 3.4, respectively) in the liver. Further, ODGD‐M2 also showed excellent motion robustness in the liver. ODGD‐Mn‐CG waveforms reduced the CG‐related dephasing effects of non CG‐nulling waveforms in phantom and in‐vivo experiments, resulting in accurate ADC maps.

Conclusions

ODGD waveforms enable motion‐robust diffusion MRI with reduced TEs, increased SNR, and reduced ADC bias compared to state‐of‐the‐art waveforms in theoretical results, simulations, phantoms and in‐vivo experiments.
Realistic 4D MRI abdominal phantom for the evaluation and comparison of acquisition and reconstruction techniques
Authors: Lo Wei‐Ching , Chen Yong , Jiang Yun , Hamilton Jesse , Grimm Robert , Griswold Mark , Gulani Vikas , Seiberlich Nicole
Published: November 2018

Purpose

This work presents a 4D numerical abdominal phantom, which includes T1 and T2 relaxation times, proton density fat fraction, perfusion, and diffusion, as well as respiratory motion for the evaluation and comparison of acquisition and reconstruction techniques.

Methods

The 3D anatomical mesh models were non‐rigidly scaled and shifted by respiratory motion derived from an in vivo scan. A time series of voxelized 3D abdominal phantom images were obtained with contrast determined by the tissue properties and pulse sequence parameters. Two example simulations: (1) 3D T1 mapping under breath‐hold and free‐breathing acquisition conditions and (2) two different reconstruction techniques for accelerated 3D dynamic contrast‐enhanced MRI, are presented. The source codes can be found at https://github.com/SeiberlichLab/Abdominal_MR_Phantom.

Results

The proposed 4D abdominal phantom can successfully simulate images and MRI data with nonrigid respiratory motion and specific contrast settings and data sampling schemes. In example 1, the use of a numerical 4D abdominal phantom was demonstrated to aid in the comparison between different approaches for volumetric T1 mapping. In example 2, the average arterial fraction over the healthy hepatic parenchyma as calculated with spiral generalized autocalibrating partial parallel acquisition was closer to that from the fully sampled data than the arterial fraction from conjugate gradient sensitivity encoding, although both are elevated compared to the gold‐standard reference.

Conclusion

This realistic abdominal MR phantom can be used to simulate different pulse sequences and data sampling schemes for the comparison of acquisition and reconstruction methods under controlled conditions that are impossible or prohibitively difficult to perform in vivo.
Optimization of phase‐contrast MRI for the estimation of global cerebral blood flow of mice at 11.7T
Authors: Wei Zhiliang , Chen Lin , Lin Zixuan , Jiang Dengrong , Xu Jiadi , Liu Peiying , van Zijl Peter C.M. , Lu Hanzhang
Published: November 2018

Purpose

To optimize phase‐contrast (PC) MRI for the measurement of global cerebral blood flow (CBF) in the mouse at 11.7T.

Methods

We determined proper velocity encoding (VENC) for internal carotid arteries (ICAs) and vertebral arteries (VAs). Next, we optimized spatial resolution of the sequence. To shorten scan time without compromising data quality, we further optimized repetition time and developed a reduced field‐of‐view (FOV) scheme for ICA and VA PC MRI. Whole‐brain volume was determined with T2‐weighted image to obtain unit‐volume CBF.

Results

Peak flow velocities were 13.8 ± 1.7, 14.4 ± 0.6, 6.5 ± 1.7, and 6.7 ± 1.3 cm/s for left ICA, right ICA, left VA, and right VA, respectively. Thus, VENC values of 20 and 10 cm/s were chosen for ICA and VA PC MRI, respectively. An in‐plane spatial resolution of 50 × 50 μm2 was found to provide a reasonable trade‐off between reducing partial‐volume effects and maintaining signal‐to‐noise ratio. Because of the fact that saturated spins in the imaging slice are rapidly replaced by fresh spins, TR of the sequence can be decreased to as short as 15 ms without reducing signal intensity, thereby substantially lowering scan time. Moreover, reduced FOV along the phase‐encoding direction was able to shorten scan time by 33.3% while maintaining measurement accuracy. With these optimizations, it took 96 seconds to evaluate CBF with a test‐retest variability of approximately 5% and an inter‐rater correlation of >0.95. Global unit‐volume CBF was found to be 279.5 ± 11.1 mL of blood/100 ml of tissue/min.

Conclusion

We have optimized PC MRI for noninvasive quantification of blood flow in mice at 11.7T.
An equilibrium‐based stress recovery procedure for the VEM
Authors: Artioli E. , de Miranda S. , Lovadina C. , Patruno L.
Published: November 2018

Within the framework of the displacement‐based virtual element method (VEM), namely, for plane elasticity, an important topic is the development of optimal techniques for the evaluation of the stress field. In fact, in the classical VEM formulation, the same projection operator used to approximate the strain field (and then evaluate the stiffness matrix) is employed to recover, via constitutive law, the stress field. Considering a first‐order formulation, strains are locally mapped onto constant functions, and stresses are piecewise constant. However, the virtual displacements might engender more complex strain fields for polygons, which are not triangles. This leads to an undesirable loss of information with respect to the underlying virtual stress field. The recovery by compatibility in patches, originally proposed for finite element schemes, is here extended to VEM, aiming at mitigating such an effect. Stresses are recovered by minimizing the complementary energy of patches of elements over an assumed set of equilibrated stress modes. The procedure is simple, efficient, and can be readily implemented in existing codes. Numerical tests confirm the good performance of the proposed technique in terms of accuracy and indicate an increase of convergence rate with respect to the classical approach in many cases.
Inverse mass matrix for isogeometric explicit transient analysis via the method of localized Lagrange multipliers
Authors: González José A. , Kopačka J. , Kolman R. , Cho S. S. , Park K. C.
Published: November 2018

A variational framework is employed to generate inverse mass matrices for isogeometric analysis (IGA). As different dual bases impact not only accuracy but also computational overhead, several dual bases are extensively investigated. Specifically, locally discontinuous biorthogonal basis functions are evaluated in detail for B‐splines of high continuity and Bézier elements with a standard C0 continuous finite element structure. The boundary conditions are enforced by the method of localized Lagrangian multipliers after generating the inverse mass matrix for completely free body. Thus, unlike inverse mass matrix methods without employing the method of Lagrange multipliers, no modifications in the reciprocal basis functions are needed to account for the boundary conditions. Hence, the present method does not require internal modifications of existing IGA software structures. Numerical examples show that globally continuous dual basis functions yield better accuracy than locally discontinuous biorthogonal functions, but with much higher computational overhead. Locally discontinuous dual basis functions are found to be an economical alternative to lumped mass matrices when combined with mass parameterization. The resulting inverse mass matrices are tested in several vibration problems and applied to explicit transient analysis of structures.
Synthesis of Metallomacrocycle and Coordination Polymers with Pyridine‐Based Amidocarboxylate Ligands and Their Catalytic Activities towards the Henry and Knoevenagel Reactions
Authors: Karmakar Anirban , Rúbio Guilherme M. D. M. , Guedes da Silva M. Fátima C. , Pombeiro Armando J. L.
Published: November 2018

The reactions of 3,3′‐{(pyridine‐2,6‐dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L) with zinc(II), cadmium(II), and samarium(III) nitrates were studied, and the obtained compounds, [Zn(1κO:2κO′‐L)(H2O)2]n (1), [Cd(1κO2:2κO2‐L)(H2O)2]2⋅6n H2O⋅ n C4H8O2⋅1.5n DMF (2), and [Sm(1κO:2κO′O′′:3κO′′′‐L)(NO3)(H2O)(dmf)]n⋅n DMF (3), were characterized by elemental analysis, FTIR spectroscopy, thermogravimetric analysis, and X‐ray single‐crystal diffraction. Compounds 1 and 3 have 1D zigzag‐ and double‐chain‐type structures, respectively, whereas 2 features a dinuclear metallomacrocyclic complex. The ligand (L2−) orients in different conformations, that is, syn‐syn for 1 and anti‐anti for 2 and 3. Compound 1 is the first example in which the syn‐syn conformation for this ligand has been observed. These compounds act as heterogeneous catalysts for the nitroaldol (Henry; in water medium) and Knoevenagel condensation reactions of different aldehydes, and the most effective is zinc coordination polymer 1. Recyclability, heterogeneity, and size‐selectivity tests were performed, which showed that the catalyst was highly active over at least four recycling runs.
Water‐Based Synthesis of Hydrophobic Ionic Liquids [N8888][oleate] and [P666,14][oleate] and their Bioprocess Compatibility
Authors: Raes Sanne M. T. , Jourdin Ludovic , Carlucci Livio , van den Bruinhorst Adriaan , Strik David P. B. T. B. , Buisman Cees J. N.
Published: November 2018

The conversion of organic waste streams into carboxylic acids as renewable feedstocks results in relatively dilute aqueous streams. Carboxylic acids can be recovered from such streams by using liquid–liquid extraction. Hydrophobic ionic liquids (ILs) are novel extractants that can be used for carboxylic acid recovery. To integrate these ILs as in situ extractants in several biotechnological applications, the IL must be compatible with the bioprocesses. Herein the ILs [P666,14][oleate] and [N8888][oleate] were synthesized in water and their bioprocess compatibility was assessed by temporary exposure to an aqueous phase that contained methanogenic granular sludge. After transfer of the sludge into fresh medium, [P666,14][oleate]‐exposed granules were completely inhibited. Granules exposed to [N8888][oleate] sustained anaerobic digestion activity, albeit moderately reduced. The IL contaminants, bromide (5–500 ppm) and oleate (10–4000 ppm), were shown not to inhibit the methanogenic conversion of acetate. [P666,14] was identified as a bioprocess‐incompatible component. However, our results showed that [N8888][oleate] was bioprocess compatible and, therefore, has potential applications in bioprocesses.
Influence of phosphorus‐grafted expandable graphite on the flame‐retardant property of UHMWPE composite
Authors: Wang Huaming , Cao Jingshi , Cao Changlin , Guo Yiyou , Luo Fubin , Qian Qingrong , Huang Baoquan , Xiao Liren , Chen Qinghua
Published: November 2018

In this paper, an efficient flame retardant, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was covalently grafted onto the surface of expandable graphite (EG). The resultant DOPO‐grafted expandable graphite (EG‐g‐DOPO) was characterized by Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and X‐ray photoelectron spectroscopy (XPS), respectively. The thermal stability of EG‐g‐DOPO was also evaluated by thermogravimetric analysis (TGA). Moreover, a series of flame‐retardant ultra‐high‐molecular‐weight polyethylene (UHMWPE) composites with various concentrations of EG‐g‐DOPO were prepared and evaluated. The results show that the UHMWPE composite with 20 wt% EG‐g‐DOPO possesses a satisfactory UL‐94 flame‐retardant grade (V‐0) and a high limiting oxygen index (30.6%). The residual char of the UHMWPE composite with higher EG‐g‐DOPO concentration shows more compact and integrated, providing an efficient barrier for heat release.
Hereditary elliptocytosis‐associated alpha‐spectrin mutation p.L155dup as a modifier of sickle cell disease severity
Authors: Risinger Mary , Christakopoulos Georgios E. , Schultz Corinna L. , McGann Patrick T. , Zhang Wenying , Kalfa Theodosia A.
Published: November 2018

The broad phenotypic variability among individuals with sickle cell disease (SCD) suggests the presence of modifying factors. We identified two unrelated SCD patients with unusually severe clinical and laboratory phenotype that were found to carry the hereditary elliptocytosis‐associated alpha‐spectrin mutation c.460_462dupTTG (p.L155dup), a mutation enriched due to positive selective pressure of malaria, similar to the SCD globin mutations. A high index of suspicion for additional hematologic abnormalities may be indicated for challenging patients with SCD. These cases highlight the validity of specialized testing such as ektacytometry and next‐generation sequencing for patients and family members to assess genotype/phenotype correlations.
Phase I study of vinblastine and temsirolimus in pediatric patients with recurrent or refractory solid tumors: Canadian Cancer Trials Group Study IND.218
Authors: Deyell Rebecca J. , Wu Bing , Rassekh S. Rod , Tu Dongsheng , Samson Yvan , Fleming Adam , Bouffet Eric , Sun Xiaoqun , Powers Jean , Seymour Lesley , Baruchel Sylvain , Morgenstern Daniel A.
Published: November 2018

Combining mammalian target of rapamycin (mTOR) inhibitors and vinca alkaloids has shown therapeutic synergy in xenograft models of pediatric cancers. This phase I study assessed safety and toxicity of temsirolimus in combination with vinblastine in children.

Procedure

Patients ≥ 1 and ≤ 18 years with recurrent/refractory solid or CNS tumors were eligible. Vinblastine (4 mg/m2) and temsirolimus (15 mg/m2) were administered i.v. weekly, with planned dose escalation of vinblastine using a rolling six phase I design. Pharmacokinetic and pharmacodynamic data were collected.

Results

Seven patients with median age 12 years (range, 8–18 years) were enrolled; all were evaluable for toxicity and six for response. At dose level 1, four of six patients developed grade 3 mucositis, of which one met duration criteria for dose‐limiting toxicity (DLT). Four patients required dose omissions for grade 3 or 4 hematologic toxicity, including one prolonged neutropenia DLT. A subsequent patient was enrolled on dose level −2 (temsirolimus 10 mg/m2, vinblastine 4 mg/m2) with no protocol‐related toxicity > grade 1, except grade 2 neutropenia. Two serious adverse events (SAE) occurred—an allergic reaction to temsirolimus (grade 2) and an intracranial hemorrhage in a CNS tumor patient (grade 3)—unlikely related to study therapy. Soluble VEGFR2 was reduced at cycle 1, day 36 in keeping with inhibition of angiogenesis. Four patients achieved prolonged stable disease for a median of 5.0 months (range, 3.1–8.3 months).

Conclusion

The combination of weekly temsirolimus (15 mg/m2) and vinblastine (4 mg/m2) exceeds the maximum tolerated dose in children, with frequent oral mucositis and hematologic toxicity.
Reliability of prenatal detection of X‐linked hypohidrotic ectodermal dysplasia by tooth germ sonography
Authors: Hammersen Johanna , Wohlfart Sigrun , Goecke Tamme W. , Köninger Angela , Stepan Holger , Gallinat Ralph , Morris Susan , Bücher Katharina , Clarke Angus , Wünsche Stephanie , Beckmann Matthias W. , Schneider Holm , Faschingbauer Florian
Published: November 2018

Objective

In X‐linked hypohidrotic ectodermal dysplasia (XLHED), dysfunction of ectodysplasin A1 (EDA1) due to EDA mutations results in malformation of hair, teeth, and sweat glands. Hypohidrosis, which can cause life‐threatening hyperthermia, is amenable to intrauterine therapy with recombinant EDA1. This study aimed at evaluating tooth germ sonography as a noninvasive means to identify affected fetuses in pregnant carrier women.

Methods

Sonography, performed at 10 study sites between gestational weeks 18 and 28, led to the diagnosis of XLHED if fewer than six tooth germs were detected in mandible or maxilla. The assessment was verified postnatally by EDA sequencing and/or clinical findings. Estimated fetal weights and postnatal weight gain of boys with XLHED were assessed using appropriate growth charts.

Results

In 19 of 38 sonographic examinations (23 male and 13 female fetuses), XLHED was detected prenatally. The prenatal diagnosis proved to be correct in 37 cases; one affected male fetus was missed. Specificity and positive predictive value were both 100%. Tooth counts obtained by clinical examination corresponded well with findings on panoramic radiographs. We observed no weight deficits of subjects with XLHED in utero but occasionally during infancy.

Conclusion

Tooth germ sonography is highly specific and reliable in detecting XLHED prenatally.
Das schnellste rotierende Objekt der Welt
Authors: Reimann René , Frimmer Martin , Novotny Lukas
Published: November 2018

Ein schwebendes Glaspartikel im Vakuum kann durch einen fokussierten Laserstrahl zu sehr schneller Rotation angetrieben werden. Unserer Forschungsgruppe an der ETH Zürich ist es auf diese Weise gelungen, ein Glaspartikel mit 100 nm Durchmesser öfter als eine Milliarde Mal pro Sekunde um die eigene Achse rotieren zu lassen [1]. Ein sich so schnell drehendes Partikel kann unter anderem für Materialtests auf der Nanoskala oder die Messung von quantenmechanischen Reibungskräften genutzt werden.
Solvent‐free ring‐opening polymerization of lactones with hydrogen‐bonding bisurea catalyst
Authors: Du Fanfan , Zheng Ying , Yuan Wenhua , Shan Guorong , Bao Yongzhong , Jie Suyun , Pan Pengju
Published: November 2018

Development of effective organocatalysts for the living ring‐opening polymerization (ROP) of lactones is highly desired for the preparation of biocompatible and biodegradable polyesters with controlled microstructures and physical properties. Herein, a new class of hydrogen‐bond donating bisurea catalysts is reported for the ROP of lactones under solvent‐free conditions. ROP of lactones mediated by the bisurea/7‐methyl‐1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (MTBD) catalyst exhibits a living/controlled manner, affording the polymers and copolymers with the well‐defined structure, predictable molecular weight, narrow molecular weight distribution, and high selectivity for monomer at low catalyst loadings at ambient temperature. The possible mechanism of bisurea/MTBD‐catalyzed ROP of lactones is proposed, in which the bisurea activates the carbonyl group of lactones while MTBD facilitates the nucleophilic attack of the initiating/propagating alcohol by hydrogen bonding. Moreover, the poly(ε‐caprolactone‐co‐δ‐valerolactone) [P(CL‐co‐VL)] random copolymers with various compositions were synthesized using the bisurea/MTBD catalyst. The measurements of thermal properties and crystalline structure demonstrate that the CL and VL units are cocrystallized in the crystalline phase of P(CL‐co‐VL) copolymers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 90–100