bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of electric, magnetic, and electromagnetic field for directed cell migration and adhesion in regenerative medicine
Authors: Ross Christina L.
Published: October 2016

Directed cell migration and adhesion is essential to embryonic development, tissue formation and wound healing. For decades it has been reported that electric field (EF), magnetic field (MF) and electromagnetic field (EMF) can play important roles in determining cell differentiation, migration, adhesion, and evenwound healing. Combinations of these techniques have revealed new and exciting explanations for how cells move and adhere to surfaces; how the migration of multiple cells are coordinated and regulated; how cellsinteract with neighboring cells, and also to changes in their microenvironment. In some cells, speed and direction are voltage dependent. Data suggests that the use of EF, MF and EMF could advance techniques in regenerative medicine, tissue engineering and wound healing. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:5–16, 2017
Bioresorbable vascular scaffolds for the treatment of coronary artery disease: Clinical outcomes from randomized controlled trials
Authors: Rizik David G , Hermiller James B , Kereiakes Dean J.
Published: October 2016

The permanent metal prosthesis common to bare metal stents (BMS) as well as both first‐ and second‐generation drug‐eluting stents (DES) following treatment of coronary artery disease represents a long‐lasting substrate for late adverse coronary events including restenosis, thrombosis, and neoatherosclerosis. Following resorbtion, bioresorbable scaffolds (BRS) may eliminate this nidus and improve late outcomes through restoration of the vessel to more normal vascular structure and function. BRS represents a single platform which incorporates the mechanical features of metallic stents to provide safe and effective revascularization, suppression of restenosis and prevention of constrictive remodeling with long‐term restoration of the treated vessel to a more natural state. The landscape of BRS is rapidly evolving with new materials which target various performance goals for the duration of vascular support and polymer resorption time. The Absorb bioresorbable vascular scaffold (Absorb BVS), recently approved by United States Food and Drug Administration, has extensive clinical evidence to date in support of its clinical efficacy and safety. Recently published data from well‐executed randomized clinical trials (RCTs) as part of the ABSORB Clinical development program along with other investigator‐initiated trials provide insights into the safety and performance of this device in patients with de novo coronary lesions as well in the setting of ST‐segment elevation myocardial infarction (STEMI). This review provides a comprehensive, outcomes based understanding of the available evidence from RCTs that offer head‐to‐head comparisons of Absorb BVS with metallic everolimus‐eluting stents (EES). © 2016 Wiley Periodicals, Inc.
Adsorption of 2‐Chlorophenol on the Surface of Silica‐ and Alumina‐Supported Iron Oxide: An FTIR and XPS Study
Authors: Mosallanejad Sara , Dlugogorski Bogdan Z. , Kennedy Eric M. , Stockenhuber Michael
Published: October 2016

The adsorption of 2‐chlorophenol (2‐CPh) on the surface of silica, alumina and silica‐ and alumina‐supported iron oxides was examined at 30 and 250 °C. The formation of a chlorophenolate carbanion/chlorophenoxy radical intermediate on the surface of silica and alumina surfaces is identified by using in situ FTIR spectroscopy. The IR spectra of 2‐CPh adsorbed on supported iron oxide at 250 °C highlight significant differences in the adsorption complex between 2‐CPh and the two supported iron oxides (on silica and alumina). Under conditions of the low coverage of 2‐CPh on the surface of these catalysts, FTIR spectroscopy was used to indicate that the adsorption of 2‐CPh on the surface of silica‐supported iron oxide commences with the formation of a chlorophenolate species, whereas 2‐CPh creates a surface formate species on alumina‐supported iron oxide. Moreover, the strong bonds of 2‐CPh and a high concentration of the carbonate species are evident on the alumina surfaces by using both FTIR and X‐ray photoelectron spectroscopy.
A Modular Approach to a Library of Semi‐Synthetic Fucosylated Chondroitin Sulfate Polysaccharides with Different Sulfation and Fucosylation Patterns
Authors: Laezza Antonio , Iadonisi Alfonso , Pirozzi Anna V. A. , Diana Paola , De Rosa Mario , Schiraldi Chiara , Parrilli Michelangelo , Bedini Emiliano
Published: October 2016

Fucosylated chondroitin sulfate (fCS)—a glycosaminoglycan (GAG) found in sea cucumbers—has recently attracted much attention owing to its biological properties. In particular, a low molecular mass fCS polysaccharide has very recently been suggested as a strong candidate for the development of an antithrombotic drug that would be safer and more effective than heparin. To avoid the use of animal sourced drugs, here we present the chemical transformation of a microbial sourced unsulfated chondroitin polysaccharide into a small library of fucosylated (and sulfated) derivatives thereof. To this aim, a modular approach based on the different combination of only five reactions was employed, with an almost unprecedented polysaccharide branching by O‐glycosylation as the key step. The library was differentiated for sulfation patterns and/or positions of the fucose branches, as confirmed by detailed 2D NMR spectroscopic analysis. These semi‐synthetic polysaccharides will allow a wider and more accurate structure–activity relationship study with respect to those reported in literature to date.
A Simple Approach to Enhance the Water Stability of a Metal‐Organic Framework
Authors: Shih Yung‐Han , Kuo Yu‐Ching , Lirio Stephen , Wang Kun‐Yun , Lin Chia‐Her , Huang Hsi‐Ya
Published: October 2016

A facile method to improve the feasibility of water‐unstable metal–organic frameworks in an aqueous environment has been developed that involves imbedding in a polymer monolith. The effect of compartment type during polymerization plays a significant role in maintaining the crystalline structure and thermal stability of the MOFs, which was confirmed by powder X‐ray diffraction (PXRD) and thermogravimetric analysis (TGA), respectively. The MOF–polymer composite prepared in a narrow compartment (column, ID 0.8 mm) has better thermal and chemical stability than that prepared in a broad compartment (vial, ID 7 mm). The developed MOF–polymer composite was applied as an adsorbent in solid‐phase microextraction of nine non‐steroidal anti‐inflammatory drugs (NSAIDs) and could be used for extraction more than 30 times, demonstrating that the proposed approach has potential for industrial applications.
Synthesis of 1,2‐Dioxetanes as Thermochemiluminescent Labels for Ultrasensitive Bioassays: Rational Prediction of Olefin Photooxygenation Outcome by Using a Chemometric Approach
Authors: Andronico Luca A. , Quintavalla Arianna , Lombardo Marco , Mirasoli Mara , Guardigli Massimo , Trombini Claudio , Roda Aldo
Published: October 2016

Great interest in new thermochemiluminescent (TCL) molecules, for example, in bioanalytical assays, has prompted the design and synthesis of a small library of more than 30 olefins to be subjected to photooxygenation, with the aim of obtaining new 1,2‐dioxetane‐based TCL labels with optimized properties. Fluorine atoms on the acridan system remarkably stabilize 1,2‐dioxetanes when they are located in the 3‐ and/or 6‐position (4 h and 4 i). On the other hand, 2,7‐difluorinated acridan dioxetane (4 j) showed a significantly enhanced fluorescence quantum yield with respect to the unsubstituted dioxetane (4 a). Some of the synthesized olefins did not undergo singlet oxygen addition and a rationale was sought to ease the photooxygenation step, leading to the TCL dioxetanes. A chemometric approach has been adopted to exploit principal component analysis and linear discriminant analysis of the structural and electronic molecular descriptors obtained by DFT optimizations of olefins 3. This approach allows the steric and electronic parameters that govern dioxetane formation to be revealed.
Mechanistic Study of the Stereoselective Hydroxylation of [2‐2H1,3‐2H1]Butanes Catalyzed by Cytochrome P450 BM3 Variants
Authors: Yang Chung‐Ling , Lin Cheng‐Hung , Luo Wen‐I , Lee Tsu‐Lin , Ramu Ravirala , Ng Kok Yaoh , Tsai Yi‐Fang , Wei Guor‐Tzo , Yu Steve S.‐F.
Published: October 2016

Engineered bacterial cytochrome P450s are noted for their ability in the oxidation of inert small alkanes. Cytochrome P450 BM3 L188P A328F (BM3 PF) and A74E L188P A328F (BM3 EPF) variants are able to efficiently oxidize n‐butane to 2‐butanol. Esterification of the 2‐butanol derived from this reaction mediated by the aforementioned two mutants gives diastereomeric excesses (de) of −56±1 and −52±1 %, respectively, with the preference for the oxidation occurring at the C−HS bond. When tailored (2R,3R)‐ and (2S,3S)‐[2‐2H1,3‐2H1]butane probes are employed as substrates for both variants, the obtained de values from (2R,3R)‐[2‐2H1,3‐2H1]butane are −93 and −92 % for BM3 PF and EPF, respectively; whereas the obtained de values from (2S,3S)‐[2‐2H1,3‐2H1]butane are 52 and 56 % in the BM3 PF and EPF systems, respectively. The kinetic isotope effects (KIEs) for the oxidation of (2R,3R)‐[2‐2H1,3‐2H1]butane are 7.3 and 7.8 in BM3 PF and EPF, respectively; whereas KIEs for (2S,3S)‐[2‐2H1,3‐2H1]butanes are 18 and 25 in BM3 PF and EPF, respectively. The discrepancy in KIEs obtained from the two substrates supports the two‐state reactivity (TSR) that is proposed for alkane oxidation in cytochrome P450 systems. Moreover, for the first time, experimental evidence for tunneling in the oxidation mediated by P450 is given through the oxidation of the C−HR bond in (2S,3S)‐[2‐2H1,3‐2H1]butane.
Rethinking Cysteine Protective Groups: S‐Alkylsulfonyl‐l‐Cysteines for Chemoselective Disulfide Formation
Authors: Schäfer Olga , Huesmann David , Muhl Christian , Barz Matthias
Published: October 2016

The ability to reversibly cross‐link proteins and peptides grants the amino acid cysteine its unique role in nature as well as in peptide chemistry. We report a novel class of S‐alkylsulfonyl‐l‐cysteines and N‐carboxy anhydrides (NCA) thereof for peptide synthesis. The S‐alkylsulfonyl group is stable against amines and thus enables its use under Fmoc chemistry conditions and the controlled polymerization of the corresponding NCAs yielding well‐defined homo‐ as well as block co‐polymers. Yet, thiols react immediately with the S‐alkylsulfonyl group forming asymmetric disulfides. Therefore, we introduce the first reactive cysteine derivative for efficient and chemoselective disulfide formation in synthetic polypeptides, thus bypassing additional protective group cleavage steps.
Modification of the Solution Behavior of Pd12L24 Metal–Organic Nanocages via PEGylation
Authors: Li Hui , Luo Jiancheng , Liu Tianbo
Published: October 2016

The dilute solutions behaviors of Pd12L24 metal–organic nanocage and its two PEGylated derivatives are explored. The basic nanocages can self‐assemble into vesicle‐like blackberry structures in polar solvents via counterion‐mediated attraction, whereas the PEGylated nanocages always stay as discrete ions under the same conditions, demonstrating that the PEGylation can improve the stability of the single nanocages. In addition, larger nanocages are found to self‐assemble in less polar solvents.
Does the S−H Bond Always Break after Adsorption of an Alkylthiol on Au(111)?
Authors: Guesmi Hazar , Luque Noelia B. , Santos Elizabeth , Tielens Frederik
Published: October 2016

The reaction mechanism for the formation of alkyl thiol self‐assembled monolayers (SAM) on Au(111) is still not clearly understood. Especially, the role of defects on the chemisorption process is an important goal to be addressed. In this work, different minimum energy reaction paths for R−SH dissociation of thiols (with long and short chains and dithiol species) adsorbed on gold adatom are calculated by using periodic density functional theory (DFT). Our results show a lower energy barrier for the RS−H bond dissociation when two thiols are adsorbed per adatom. In addition, in contrast with the formation of an adatom at the Au(111) which has been shown to depend on the alkyl chain length, the activation energy of the RS−H bond dissociation of thiols adsorbed on an adatom was shown to be independent of the alkyl chain length. The presented results and derived hypothesis support the model that thiols with long alkyl chain thiols mainly adsorb molecularly on Au(111), while for short alkyl chain thiols the S−H bond breaks. This result is explained by the fact that short‐chain thiols have lower interchain interaction energies and are thus more mobile compared to the long alkyl chain thiols on the Au(111) surface. This feature enables the short chains to reach adequate geometries, driven by entropy, which could deform the Au(111) more drastically and probably pull Au atoms out from surface to form adatoms. With these results a new mechanism is proposed for the formation of alkyl chain thiols on Au(111).
Manganese‐Catalyzed Hydrogenation of Esters to Alcohols
Authors: Espinosa‐Jalapa Noel Angel , Nerush Alexander , Shimon Linda J. W. , Leitus Gregory , Avram Liat , Ben‐David Yehoshoa , Milstein David
Published: October 2016

Homogeneous catalytic hydrogenation of esters to alcohols is an industrially important, environmentally benign reaction. While precious metal‐based catalysts for this reaction are now well known, only very few catalysts based on first‐row metal complexes were reported. Here we present the hydrogenation of esters catalyzed by a complex of earth‐abundant manganese. The reaction proceeds under mild conditions and insight into the mechanism is provided based on an NMR study and the synthesis of novel Mn complexes postulated as intermediates.
Periodic Mesoporous Organosilica with a Basic Urea‐Derived Framework for Enhanced Carbon Dioxide Capture and Conversion Under Mild Conditions
Authors: Liu Mengshuai , Lu Xingyuan , Shi Lei , Wang Fangxiao , Sun Jianmin
Published: October 2016

A periodic mesoporous organosilica with a basic urea‐derived framework (PMO‐UDF) was prepared and characterized thoroughly. The PMO‐UDF showed an enhanced CO2 capture capacity at low pressure (≤1 atm) and an exceptional catalytic activity in CO2 coupling reactions with various epoxides to yield the corresponding cyclic carbonates under mild conditions because of the presence of a high surface area, basic pyridine units, and multiple hydrogen‐bond donors. The highly stable catalyst could be reused at least six successive times without a significant decrease of the catalytic efficiency or structural deterioration, thus the PMO‐UDF composite is considered as a promising material for CO2 capture and conversion.
New Redox Polymers that Exhibit Reversible Cleavage of Sulfur Bonds as Cathode Materials
Authors: Baloch Marya , Ben Youcef Hicham , Li Chunmei , Garcia‐Calvo Oihane , Rodriguez Lide M. , Shanmukaraj Devaraj , Rojo Teofilo , Armand Michel
Published: October 2016

Two new cathode materials based on redox organosulfur polymers were synthesized and investigated for rechargeable lithium batteries as a proof‐of‐concept study. These cathodes offered good cycling performance owing to the absence of polysulfide solubility, which plagues Li/S systems. Herein, an aliphatic polyamine or a conjugated polyazomethine was used as the base to tether the redox‐active species. The activity comes from the cleavage and formation of S−S or N−S bonds, which is made possible by the rigid conjugated backbone. The synthesized polymers were characterized through FTIR spectroscopy and thermogravimetric analysis (TGA). Galvanostatic measurements were performed to evaluate the discharge/charge cycles and characterize the performance of the lithium‐based cells, which displayed initial discharge capacities of approximately 300 mA h g−1 at C/5 over 100 cycles with approximately 98 % Coulombic efficiency.
Degradation of lignin and cellulose during foliar litter decomposition in an alpine forest river
Authors: Yue Kai , Peng Changhui , Yang Wanqin , Peng Yan , Zhang Chuan , Huang Chunping , Wu Fuzhong
Published: October 2016

Lignin and cellulose are thought to be critical factors that affect the rate of litter decomposition; however, few data are available on their degradation dynamics during litter decomposition in lotic ecosystems, such as forest rivers, where litter can decompose much more rapidly than in terrestrial ecosystems. We studied the degradation of lignin and cellulose in the foliar litter of four dominant riparian species (willow:Salix paraplesia; azalea:Rhododendron lapponicum; cypress:Sabina saltuaria; and larch:Larix mastersiana) in an alpine forest river. Over an entire year's incubation, litter lignin and cellulose degraded by 14.7–100% and 57.7–100% of their initial masses, respectively, depending on litter species. Strong degradations of lignin and cellulose occurred in the prefreezing period (i.e., the first 41 d) during litter decomposition, and the degradation rate was the highest among all the decomposition periods regardless of litter species. Litter species, decomposition period, and environmental factors such as temperature and nutrient availability showed significant influences on lignin and cellulose degradation rates. Compared with previously reported data regarding the dynamics of lignin and cellulose during litter decomposition in terrestrial ecosystems, our results suggest that lignin and cellulose can be degraded much more rapidly in lotic ecosystems, indicating that the traditionally used two‐phased model for the dynamics of lignin in decomposing litter may not be suitable in lotic ecosystems.
An evaluation of inclusive capital stock for urban planning
Authors: Fujii Hidemichi , Managi Shunsuke
Published: October 2016

Rapid urbanization has caused significant problems, and sustainable city design can play an important role in solving these problems under limited budgets and resources. Previous studies have proposed city evaluation indicators that can suggest appropriate urban designs. However, these indicators do not clearly consider economic theory, which is crucial for understanding accumulation of urban capital stock by the flows from daily urban activities. This study proposes a research framework based on economic theory for evaluating urban sustainability; this framework uses the inclusive wealth index (IWI) concept to examine inclusive urban capital stock. It examines the advantages of using the IWI as a city evaluation indicator along with data envelopment analysis and a decomposition analysis framework. We use data for 20 Japanese ordinance‐designated cities for an empirical study to demonstrate a proposed approach for evaluating inclusive urban capital. The developed research application evaluates each city's relative superiority in terms of capital accumulation and identifies those factors determining changes in capital flows via changes in efficiency, priority, and scale. The combination of these results can be helpful to decision makers seeking to increase urban capital by considering reference city information and relative superiority.
Characterization of heavy metals in soils from typical tobacco cultivated areas, China
Authors: Lin Beisen , Gao Huajun , Lai Hongmin , Li Chunhua , Wang Quan
Published: October 2016

The heavy metal in tobacco has been widely concerned for the toxicity and bioaccumulation. Heavy metal in tobacco is of extremely related with the corresponding concentration in soil. One hundred soil samples were collected from five typical tobacco cultivated areas to evaluate the environmental quality and health implications. The inductively coupled plasma mass spectrometry was employed to determine the concentrations of heavy metals (As, Cd, Cr, Cu, Hg, and Pb). The geo‐accumulation index and potential health risk assessment were performed to investigate the environmental quality and health risk. The concentrations of As, Cd, Cr, Cu, Hg, and Pb are ranged from 0.40 to 112 mg/kg, 0.07 to 4.22 mg/kg, 5.52 to 338 mg/kg, 3.40 to 64.5 mg/kg, 0 to 1.62 mg/kg, respectively. The concentrations of heavy metals are various among the five different typical cultivation areas. The elevated concentrations of heavy metals in the selected soils suggesting that these heavy metals may be derived from anthropogenic sources i.e. industrial and agricultural activities. The results shown that the soils in the Jingxi, Longlin, and Debao County are posed to a moderately to heavily contamination for Hg and Cd. The noncarcinogenic and carcinogenic effects (except Lingyun County) caused by heavy metal exposure is regarded as acceptable. The Lingyun County soil should be paid more attention due to the unacceptable level of carcinogenic risk. As, Cd, Hg, and Cr are regarded as the priority control metals. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 483–488, 2017
White matter structural network abnormalities underlie executive dysfunction in amyotrophic lateral sclerosis
Authors: Dimond Dennis , Ishaque Abdullah , Chenji Sneha , Mah Dennell , Chen Zhang , Seres Peter , Beaulieu Christian , Kalra Sanjay
Published: October 2016

Research in amyotrophic lateral sclerosis (ALS) suggests that executive dysfunction, a prevalent cognitive feature of the disease, is associated with abnormal structural connectivity and white matter integrity. In this exploratory study, we investigated the white matter constructs of executive dysfunction, and attempted to detect structural abnormalities specific to cognitively impaired ALS patients. Eighteen ALS patients and 22 age and education matched healthy controls underwent magnetic resonance imaging on a 4.7 Tesla scanner and completed neuropsychometric testing. ALS patients were categorized into ALS cognitively impaired (ALSci, n = 9) and ALS cognitively competent (ALScc, n = 5) groups. Tract‐based spatial statistics and connectomics were used to compare white matter integrity and structural connectivity of ALSci and ALScc patients. Executive function performance was correlated with white matter FA and network metrics within the ALS group. Executive function performance in the ALS group correlated with global and local network properties, as well as FA, in regions throughout the brain, with a high predilection for the frontal lobe. ALSci patients displayed altered local connectivity and structural integrity in these same frontal regions that correlated with executive dysfunction. Our results suggest that executive dysfunction in ALS is related to frontal network disconnectivity, which potentially mediates domain‐specific, or generalized cognitive impairment, depending on the degree of global network disruption. Furthermore, reported co‐localization of decreased network connectivity and diminished white matter integrity suggests white matter pathology underlies this topological disruption. We conclude that executive dysfunction in ALSci is associated with frontal and global network disconnectivity, underlined by diminished white matter integrity. Hum Brain Mapp 38:1249–1268, 2017. © 2016 Wiley Periodicals, Inc.
Upregulation of endothelial gene markers in Wharton's jelly mesenchymal stem cells cultured on polyelectrolyte multilayers
Authors: Rammal Hassan , Harmouch Chaza , Maerten Clément , Gaucher Caroline , Boulmedais Fouzia , Schaaf Pierre , Voegel Jean Claude , Laurent‐Maquin Dominique , Menu Patrick , Kerdjoudj Halima
Published: October 2016

Designing convenient substrates is a pertinent parameter that can guide stem cell differentiation. Current research is directed toward differentiating mesenchymal stem cells (MSCs) into endothelial cells (ECs). It is generally accepted that MSCs cannot be easily differentiated into ECs without high concentrations of proangiogenic factors. To guide either bone marrow‐derived mesenchymal stem cells (BM‐MSCs) and Wharton's jelly‐derived mesenchymal stem cells (WJ‐MSCs) into ECs‐like phenotype, poly(allylamine‐hydrochloride)/poly(styrene‐sulfonate) multilayers film (PAH/PSS) was used as culture coating and compared to type I collagen (as control coating). After 2 weeks of culture and in absence of angiogenic growth factors, PAH/PSS upregulated KDR, PECAM‐1, and CDH5 genes, whereas combining PAH/PSS with endothelial growth media (EGM‐2®) led to the production of respective proteins by WJ‐MSCs. In contrast, not fully EC‐like phenotype is obtained from the differentiation of BM‐ or WJ‐MSCs cultured on type I collagen. Thus, using PAH/PSS coating in synergy with EGM‐2® appears as an ideal condition promoting WJ‐MSCs differentiation into ECs‐like. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 292–300, 2017.
Intravoxel incoherent motion (IVIM)‐derived parameters in diffusion‐weighted MRI: Associations with prognostic factors in invasive ductal carcinoma
Authors: Lee Youn Joo , Kim Sung Hun , Kang Bong Joo , Kang Young Jee , Yoo Heesoo , Yoo Jaewan , Lee Jaeun , Son Yo Han , Grimm Robert
Published: October 2016

Purpose

To investigate relationships between intravoxel incoherent motion (IVIM) metrics of invasive ductal carcinoma of the breast and prognostic factors.

Materials and Methods

This retrospective study included a total of 82 masses from 72 patients who underwent 3T breast magnetic resonance imaging (MRI) and diffusion‐weighted imaging. IVIM metrics of tissue diffusivity (Dslow), pseudodiffusivity (Dfast), and perfusion fraction (Dpf) were measured using histogram analysis for whole lesion volumes. We evaluated relationships between IVIM metrics and prognostic factors or subtypes of invasive ductal carcinoma.

Results

The Dslow 50th, 75th, and 90th percentile metrics were reduced in the estrogen receptor (ER)‐positive group compared with the ER‐negative group (individually, P = 0.044, 0.024, 0.045). Additionally, the Dslow 75th percentile value was a significant differentiator of histologic grade, tumor subtype, and Ki‐67 grouping (individually, P = 0.024, 0.049, 0.016). The Dpf mean, 75th, 90th percentile, skewness, and kurtosis metrics were correlated with the size of ductal carcinoma in situ (DCIS) component (individually, P = 0.034, 0.032, 0.027, 0.013, 0.013).

Conclusion

The Dslow metrics differentiated between ER‐positive and ‐negative groups, and the Dpf metrics were associated with the size of the DCIS component.

Level of Evidence: 4

J. MAGN. RESON. IMAGING 2017;45:1394–1406
PET/MRI of metabolic activity in osteoarthritis: A feasibility study
Authors: Kogan Feliks , Fan Audrey P. , McWalter Emily J. , Oei Edwin H. G. , Quon Andrew , Gold Garry E.
Published: October 2016

Purpose

To evaluate positron emission tomography / magnetic resonance imaging (PET/MRI) knee imaging to detect and characterize osseous metabolic abnormalities and correlate PET radiotracer uptake with osseous abnormalities and cartilage degeneration observed on MRI.

Materials and Methods

Both knees of 22 subjects with knee pain or injury were scanned at one timepoint, without gadolinium, on a hybrid 3.0T PET‐MRI system following injection of 18F‐fluoride or 18F‐fluorodeoxyglucose (FDG). A musculoskeletal radiologist identified volumes of interest (VOIs) around bone abnormalities on MR images and scored bone marrow lesions (BMLs) and osteophytes using a MOAKS scoring system. Cartilage appearance adjacent to bone abnormalities was graded with MRI‐modified Outerbridge classifications. On PET standardized uptake values (SUV) maps, VOIs with SUV greater than 5 times the SUV in normal‐appearing bone were identified as high‐uptake VOI (VOIHigh). Differences in 18F‐fluoride uptake between bone abnormalities, BML, and osteophyte grades and adjacent cartilage grades on MRI were identified using Mann–Whitney U‐tests.

Results

SUVmax in all subchondral bone lesions (BML, osteophytes, sclerosis) was significantly higher than that of normal‐appearing bone on MRI (P < 0.001 for all). Of the 172 high‐uptake regions on 18F‐fluoride PET, 63 (37%) corresponded to normal‐appearing subchondral bone on MRI. Furthermore, many small grade 1 osteophytes (40 of 82 [49%]), often described as the earliest signs of osteoarthritis (OA), did not show high uptake. Lastly, PET SUVmax in subchondral bone adjacent to grade 0 cartilage was significantly lower compared to that of grades 1–2 (P < 0.05) and grades 3–4 cartilage (P < 0.001).

Conclusion

PET/MRI can simultaneously assess multiple early metabolic and morphologic markers of knee OA across multiple tissues in the joint. Our findings suggest that PET/MR may detect metabolic abnormalities in subchondral bone, which appear normal on MRI.

Level of Evidence: 2

Technical Efficacy: Stage 1

J. MAGN. RESON. IMAGING 2017;45:1736–1745
Positive Group Affective Tone and Team Creative Performance and Change‐Oriented Organizational Citizenship Behavior: A Moderated Mediation Model
Authors: Shin Yuhyung , Kim Mihee , Lee Sang‐Hoon
Published: October 2016

Despite the vast amount of research on creativity and organizational citizenship behavior (OCB), little knowledge has been accumulated with respect to underlying mechanisms and boundary conditions affecting team creative performance and change OCB. To fill this research gap, this study aims at proposing and testing a moderated mediation model that delineates the relationships among positive group affective tone (PGAT), team reflexivity, team leader transformational leadership, team creative performance, and team change OCB. As hypothesized, PGAT was positively associated with team reflexivity, which in turn significantly predicted team creative performance and change OCB. In addition, the relationship between PGAT and team reflexivity and the indirect effects of PGAT on team creative performance and change OCB through team reflexivity were more pronounced when team leader transformational leadership was high than when it was low. These findings were validated in a post hoc analysis that compared the proposed moderated mediation model with alternative models.
Correction of phase errors in quantitative water–fat imaging using a monopolar time‐interleaved multi‐echo gradient echo sequence
Authors: Ruschke Stefan , Eggers Holger , Kooijman Hendrik , Diefenbach Maximilian N. , Baum Thomas , Haase Axel , Rummeny Ernst J. , Hu Houchun H. , Karampinos Dimitrios C.
Published: October 2016

Purpose

To propose a phase error correction scheme for monopolar time‐interleaved multi‐echo gradient echo water–fat imaging that allows accurate and robust complex‐based quantification of the proton density fat fraction (PDFF).

Methods

A three‐step phase correction scheme is proposed to address a) a phase term induced by echo misalignments that can be measured with a reference scan using reversed readout polarity, b) a phase term induced by the concomitant gradient field that can be predicted from the gradient waveforms, and c) a phase offset between time‐interleaved echo trains. Simulations were carried out to characterize the concomitant gradient field‐induced PDFF bias and the performance estimating the phase offset between time‐interleaved echo trains. Phantom experiments and in vivo liver and thigh imaging were performed to study the relevance of each of the three phase correction steps on PDFF accuracy and robustness.

Results

The simulation, phantom, and in vivo results showed in agreement with the theory an echo time‐dependent PDFF bias introduced by the three phase error sources. The proposed phase correction scheme was found to provide accurate PDFF estimation independent of the employed echo time combination.

Conclusion

Complex‐based time‐interleaved water–fat imaging was found to give accurate and robust PDFF measurements after applying the proposed phase error correction scheme. Magn Reson Med 78:984–996, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Diffusion‐weighted J‐resolved spectroscopy
Authors: Landheer Karl , Schulte Rolf , Geraghty Ben , Hanstock Christopher , Chen Albert P. , Cunningham Charles H. , Graham Simon J.
Published: October 2016

Purpose

To develop a novel diffusion‐weighted magnetic resonance spectroscopy (DW‐MRS) technique in conjunction with J‐resolved spatially localized spectroscopy (JPRESS) to measure the apparent diffusion coefficients (ADCs) of brain metabolites beyond N‐acetylaspartic acid (NAA), creatine (Cr), and choline (Cho) at 3T. This technique will be useful to probe tissue microstructures in vivo, as the various metabolites have different physiological characteristics.

Methods

Two JPRESS spectra were collected (high b‐value and low b‐value), and the ADCs of 16 different metabolites were estimated. Two analysis pipelines were developed: 1) a 2D pipeline that uses ProFit software to extract ADCs from metabolites not typically accessible at 3T and 2) a 1D pipeline that uses TARQUIN software to extract the metabolite concentrations from each line in the 2D dataset, allowing for scaling as well as validation.

Results

The ADCs of 16 different metabolites were estimated from within six subjects in parietal white matter. There was excellent agreement between the results obtained from the 1D and 2D pipelines for NAA, Cr, and Cho.

Conclusion

The proposed technique provided consistent estimates for the ADCs of NAA, Cr, Cho, glutamate + glutamine, and myo‐inositol in all subjects and additionally glutathione and scyllo‐inositol in all but one subject. Magn Reson Med 78:1235–1245, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Quantitative measurement of cerebral blood volume using velocity‐selective pulse trains
Authors: Liu Dexiang , Xu Feng , Lin Doris D. , van Zijl Peter C.M. , Qin Qin
Published: October 2016

Purpose

To develop a non–contrast‐enhanced MRI method for cerebral blood volume (CBV) mapping using velocity‐selective (VS) pulse trains.

Methods

The new pulse sequence applied velocity‐sensitive gradient waveforms in the VS label modules and velocity‐compensated ones in the control scans. Sensitivities to the gradient imperfections (e.g., eddy currents) were evaluated through phantom studies. CBV quantification procedures based on simulated labeling efficiencies for arteriolar, capillary, and venular blood as a function of cutoff velocity (Vc) are presented. Experiments were conducted on healthy volunteers at 3T to examine the effects of unbalanced diffusion weighting, cerebrospinal (CSF) contamination and variation of Vc.

Results

Phantom results of the used VS pulse trains demonstrated robustness to eddy currents. The mean CBV values of gray matter and white matter for the experiments using Vc = 3.5 mm/s and velocity‐compensated control with CSF‐nulling were 5.1 ± 0.6 mL/100 g and 2.4 ± 0.2 mL/100 g, respectively, which were 23% and 32% lower than results from the experiment with velocity‐insensitive control, corresponding to 29% and 25% lower in averaged temporal signal‐to‐noise ratio values.

Conclusion

A novel technique using VS pulse trains was demonstrated for CBV mapping. The results were both qualitatively and quantitatively close to those from existing methods. Magn Reson Med 77:92–101, 2017. © 2016 International Society for Magnetic Resonance in Medicine
Increased robustness in reference region model analysis of DCE MRI using two‐step constrained approaches
Authors: Ahmed Zaki , Levesque Ives R.
Published: October 2016

Purpose

Reference region models (RRMs) can quantify tumor perfusion in dynamic contrast‐enhanced MRI without an arterial input function. Inspection of the RRM reveals that one of the free parameters in the fit is uniquely linked to the reference region and is common to all voxels. A two‐step approach is proposed that takes this constraint into account.

Methods

Three constrained RRM (CRRM) approaches were devised and evaluated. Simulations were performed to compare their accuracy and precision over a range of noise and temporal resolutions. The CRRM was also applied on a virtual phantom that simulates different perfusion values. In vivo evaluation was performed on data from breast cancer and soft tissue sarcoma.

Results

In simulations, the CRRM consistently improved precision and had better accuracy at low signal‐to‐noise ratio (SNR). In virtual phantom, the CRRMs were able to fit voxels that had similar kinetics to the reference tissue, whereas the unconstrained models failed to accurately fit these voxels. In the in vivo data, the constrained approaches produced parameter maps that had less variability and were in better agreement with the Tofts model.

Conclusion

These findings indicate that the two‐step fitting approach of the CRRM can reduce the variability of perfusion estimates for quantifying perfusion with dynamic contrast‐enhanced (DCE) MRI. Magn Reson Med 78:1547–1557, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Local SAR near deep brain stimulation (DBS) electrodes at 64 and 127 MHz: A simulation study of the effect of extracranial loops
Authors: Golestanirad Laleh , Angelone Leonardo M. , Iacono Maria Ida , Katnani Husam , Wald Lawrence L. , Bonmassar Giorgio
Published: October 2016

Purpose

MRI may cause brain tissue around deep brain stimulation (DBS) electrodes to become excessively hot, causing lesions. The presence of extracranial loops in the DBS lead trajectory has been shown to affect the specific absorption rate (SAR) of the radiofrequency energy at the electrode tip, but experimental studies have reported controversial results. The goal of this study was to perform a systematic numerical study to provide a better understanding of the effects of extracranial loops in DBS leads on the local SAR during MRI at 64 and 127 MHz.

Methods

A total of 160 numerical simulations were performed on patient‐derived data, in which relevant factors including lead length and trajectory, loop location and topology, and frequency of MRI radiofrequency (RF) transmitter were assessed.

Results

Overall, the presence of extracranial loops reduced the local SAR in the tissue around the DBS tip compared with straight trajectories with the same length. SAR reduction was significantly larger at 127 MHz compared with 64 MHz. SAR reduction was significantly more sensitive to variable loop parameters (eg, topology and location) at 127 MHz compared with 64 MHz.

Conclusion

Lead management strategies could exist that significantly reduce the risks of 3 Tesla (T) MRI for DBS patients. Magn Reson Med 78:1558–1565, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Leveraging Academic Partnerships to Improve Logistics at Nonprofit Organizations
Authors: Manikas Andrew S. , Kroes James R. , Gattiker Thomas F.
Published: October 2016

This article presents the results of a partnership between a nonprofit organization and a team of academic researchers that developed a low‐cost spreadsheet‐based tool that allows organizations to effectively schedule vehicle operations. Specifically, the tool (1) handles the real‐world constraints present in moderately complex logistics environments; and (2) uses general computing hardware and software that is already deployed in most organizations, thereby rendering the solution radically low cost (effectively free). We deployed this tool to a humanitarian organization, the Idaho Foodbank, which realized a substantial improvement in its fleet efficiency and a corresponding reduction in route‐planning time. The methodology used to manage this collaboration with academia can be leveraged by other nonprofit organizations attempting to overcome the financial barriers that commonly prevent budget‐constrained organizations from accessing advanced technologies.
Binge abstinence is associated with reduced energy intake after treatment in patients with binge eating disorder and obesity
Authors: Masheb Robin M. , Dorflinger Lindsey M. , Rolls Barbara J. , Mitchell Diane C. , Grilo Carlos M.
Published: October 2016

Objective

Binge eating disorder (BED) is strongly associated with obesity and related medical and psychiatric morbidities. Cognitive behavioral therapy (CBT) has consistently been shown to reduce binge eating frequency and improve psychological functioning, as well as to produce abstinence rates of roughly 50%. This study examined the relationship between binge abstinence and dietary and psychological outcomes after CBT for BED.

Methods

Fifty adult patients with BED received 6‐month treatments using a combination of CBT and dietary counseling. Trained interviewers conducted two 24‐hour dietary recall interviews on randomly selected days at baseline and at 6 months.

Results

Participants had significant reductions in energy, macronutrient, and sugar intake and an increase in fruit intake. They reported significant reductions in BMI and binge eating frequency (from mean = 14.24 to mean = 1.90 binge eating episodes during the previous 28 days), as well as improvements in psychological functioning. Those who became binge abstinent reported eating roughly 400 fewer calories per day and experienced greater improvements in psychological functioning than those who did not.

Conclusions

Findings from this study suggest that individuals who achieve complete cessation from binge eating have significantly improved dietary and psychological outcomes that could potentially improve weight status, compared with those who continue to binge eat post‐treatment.
Shape recovery liquid crystal elastomer synthesized by melt‐polycondensation
Authors: Xu Mingyao , Cong Yuehua , Zhang Baoyan
Published: October 2016

A novel liquid crystal elastomer (LCE) synthesized by melt polymerization, which exhibits the capacity of shape memory, is reported here for the first time. The method of synthesize the shape memory LCE has been explored. A facile two‐step method to synthesize these anisotropic materials to realize reversible shape change behavior is reported. The first reaction is the addition of nematic liquid crystal molecules to form a kind of liquid crystal polymer. Subsequently, the polymer is crosslinked to trap the order of the liquid crystal into a crosslinked LCE. The LCE exhibits liquid crystalline behavior which has shape memory with excellent fixity and recovery. Its shape memory and actuating properties also have been studied. When reheating the LCE to 165 °C, the shape will recover. The main chains and crosslinked bonds of the LCE contain ester groups, which are sensitive to alkaline and acidic condition. It turns out that the LCE is intact under acidic condition, but it can be degraded under alkaline condition. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 389–394
Preparation of fluorinated methacrylate/clay nanocomposite via in‐situ polymerization: Characterization, structure, and properties
Authors: Karamane Mohamed , Raihane Mustapha , Tasdelen Mehmet Atilla , Uyar Tamer , Lahcini Mohamed , Ilsouk Mohamed , Yagci Yusuf
Published: October 2016

Novel fluorinated coating containing well‐dispersed silicate nanolayers is successfully produced via in‐situ free radical polymerization of 2,2,2‐trifluoroethyl methacrylate in the presence of vinylbenzyl‐functionalized montmorillonite with different loading. The organic modification of sodium montmorillonite is achieved through an ion exchange reaction with triphenylvinylbenzylphosphonium chloride as surfactant prepared before use by reaction with vinylbenyl chloride and phosphine. The following in‐situ polymerization in the presence of organomodified clay leads to fluorinated nanocomposites with of partially exfoliated and intercalated morphologies, as determined via XRD and TEM analysis. The nanoscale dispersion of clay layers is also evidenced by thermal analysis; a moderate decrease of the glass transition temperature about 2–8 °C compared to their virgin PMATRIF and an improvement of their thermal stability as evidenced by TGA. The wettability of the nanocomposite films is also studied by contact angle measurements with water. The incorporation of organomodified clays not only increases the hydrophobicity of the fluorinated polymers but also improves the surface properties of obtained nanocomposites. Compared the virgin homopolymer, the mechanical properties of the nanocomposites are reduced by addition of organomodifed clay at temperature from 30 to 60 °C, whereas this trend is gradually decreased at higher temperature. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 411–418
An analysis of the role of nonreactive plasticizers in the crosslinking reactions of a rigid resin
Authors: Patel Jigneshkumar P. , Deshmukh Subrajeet , Zhao Caixia , Wamuo Onyenkachi , Hsu Shaw Ling , Schoch Andrew B. , Carleen Sena Ada , Matsumoto Dean
Published: October 2016

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multiple components. Using a combination of infrared spectroscopy, thermal analysis, and low field NMR, we have elucidated the role of a new class of nonreactive plasticizers on the crosslinking reaction between hexamethylenetetramine (HMTA) and phenol formaldehyde resin. These two seemingly dissimilar reactants are responsible for the exceptionally high mechanical strength in a number of organic–inorganic composites. The efficiency of the curing reaction is characterized by the changing functionality of HMTA. Infrared active vibrations are used to characterize the changing molecular structures as a function of temperature. The T1 spin‐lattice relaxation time is used for the characterization of segmental dynamics of the chains in the formation of the crosslinked product. The segmental mobility depends on the amount of crosslinking and the stiffness of the chain. This study shows that this new class of nonreactive plasticizer can induce highly crosslinked structures without any of the environmental impact of the current technology. An efficient crosslinking reaction in phenolic resin can be achieved by using methyl benzoate as a nonreacting plasticizer. Low field NMR, in conjunction with infrared spectroscopy (mid and near) and DSC, clarified the crosslinking reaction mechanism and the ensuing structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 206–213
A novel model to predict infinite dilution solubility coefficients in glassy polymers
Authors: Goubko Mikhail , Miloserdov Oleg , Yampolskii Yuri , Alentiev Alexander , Ryzhikh Victoria
Published: October 2016

Infinite dilution gas solubility coefficients in glassy polymers of diverse chemical structure are predicted on the basis of a simple computational model of short polymer chain conformations. In contrast to existing models that describe the infinite dilution solubility coefficientSof various gases in certain polymers orSfor the particular gas in different polymers, our approach allows to deal with the broad variety of gases and glassy polymers of different structure. With the van der Waals volume, accessible surface area, and some derivative geometrical descriptors being the predicting variables, the multivariate linear regression on the testing set gives correlation 0.89 with the logarithm of the solubility coefficient for the considered classes of relatively low‐permeable polymers (the mean relative error of solubility coefficientSprediction is 68%). Regression accuracy can be improved up to correlation 0.95 and the mean relative error 39% when a separate regression is constructed for each penetrant gas. Implications are discussed to the analysis of solubility selectivity. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2017,55, 228–244