bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polypropylene/Cellulose Composites for Material Extrusion Additive Manufacturing
Authors: Kaynak Baris , Spoerk Martin , Shirole Anuja , Ziegler Wolfgang , Sapkota Janak 
Published: April 2018

AbstractThe preparation of polypropylene (PP)/microcrystalline cellulose (MCC) composites and their applicability for material extrusion additive manufacturing (ME‐AM) is reported. MCC is modified by grafting onto its surface with different silanes, in particular perfluorooctyltriethoxysilane,n‐octyltriethoxysilane (OTS), or aminopropyltriethoxysilane. The efficacy of the surface modification is confirmed by attenuated total reflectance and X‐ray photoelectron spectroscopy. The affinity of the modified MCC to the polar PP matrix is investigated by direct melt‐compounding, and the applicability of the resulting composites for material ME‐AM is accessed by fabrication of filaments and evaluating the relevant property requirements. The surface modification of the MCC improves their dispersibility in PP and enhances the mechanical properties of the composites. Moreover, the OTS‐modified MCC shows the best reinforcement, good surface finish of the filament, and flawless printability.
Recyclable Crosslinked High‐Performance Polymers via Adjusting Intermolecular Cation–π Interactions and the Visual Detection of Tensile Strength and Glass Transition Temperature
Authors: Yang Li , Du Mengqi , Yang Shien , Wei Wenxuan , Chang Guanjun 
Published: April 2018

AbstractCrosslinked high‐performance polymers have many industrial applications but are difficult to recycle. Visual detection of the physical properties of the crosslinked high‐performance polymers is useful, but is difficult to achieve. The crosslinked high‐performance polymers (SPIN) are constructed by using cation–π interactions. The cation–π interaction between the polymer side chains can be easily installed and removed by aqueous treatments at high or low pH, respectively, which endow the crosslinked polymer with a recyclable behavior. Additionally, the tensile strength and glass transition temperature of the SPIN films could be visually detected by taking advantage of the transparency decreasing effect of cation to an adjacent indole unit.
The Effect of End Group and Molecular Weight on the Yellowness of Polyetherimide
Authors: Cao Ke , Zhang Mingxuan , Liu Guoliang 
Published: April 2018

AbstractThe effects of end group and molecular weight on the yellowness of telechelic polyetherimide (PEI) are investigated. Electron‐withdrawing dianhydride end groups reduce the yellowness and increase the transparency of PEI regardless of the molecular weight. Electron‐donating phenyl, amine, and phthalic end groups increase the yellowness of PEI but the effect depends on the molecular weight. As the molecular weight is increased, the yellowness of PEIs with electron‐donating end groups initially decreases due to a decreasing end‐group density and then increases due to an increasing probability of charge‐transfer complex formation. The systematic study reveals the correlations among yellowness, end group, and molecular weight of PEIs. The correlations can be used for designing highly transparent PEIs and other high‐performance polymers.
A Color‐Tunable Fluorescent Supramolecular Hyperbranched Polymer Constructed by Pillar[5]arene‐Based Host–Guest Recognition and Metal Ion Coordination Interaction
Authors: Li Hui , Chen Wenzhuo , Xu Fenfen , Fan Xiaodong , Liang Tongxiang , Qi Xiaopeng , Tian Wei 
Published: April 2018

AbstractFluorescent supramolecular polymers are an important kind of smart material. In this work, a new fluorescent supramolecular hyperbranched polymer (FSHP) is constructed by orthogonal self‐assembly: pillararene‐based host–guest interaction and metal ion complexation interaction. The FSHP exhibits concentration‐controllable fluorescence emissions. The photoluminescence spectra and light‐emitting colors of FSHP can be effectively tuned by changing metal ion types or using mixed metal ions. The fluorescence quenching of FSHP solutions or FSHP‐based films would occur when removing the metal ions from the backbone of FSHP. This study supplies a convenient approach toward the construction of structure‐tunable fluorescent supramolecular materials with different colors.
Melt Electrowriting of Thermoplastic Elastomers
Authors: Hochleitner Gernot , Fürsattel Eva , Giesa Reiner , Groll Jürgen , Schmidt Hans‐Werner , Dalton Paul D. 
Published: April 2018

AbstractMelt electrowriting (MEW), an additive manufacturing process, is established using polycaprolactone as the benchmark material. In this study, a thermoplastic elastomer, namely, poly(urea‐siloxane), is synthesized and characterized to identify how different classes of polymers are compatible with MEW. This polyaddition polymer has reversible hydrogen bonding from the melt upon heating/cooling and highly resolved structures are achieved by MEW. The influence of applied voltage, temperature, and feeding pressure on printing outcomes behavior is optimized. Balancing these parameters, highly uniform and smooth‐surfaced fibers with diameters ranging from 10 to 20 µm result. The quality of the 3D MEW scaffolds is excellent, with very accurate fiber stacking capacity—up to 50 layers with minimal defects and good fiber fusion between the layers. There is also minimal fiber sagging between the crossover points, which is a characteristic of thicker MEW scaffolds previously reported with other polymers. In summary, poly(urea‐siloxane) demonstrates outstanding compatibility with the MEW process and represents a class of polymer—thermoplastic elastomers—that are, until now, untested with this approach.
In Silico Tracking of Individual Species Accelerating Progress in Macromolecular Engineering and Design
Authors: D'hooge Dagmar R. 
Published: April 2018

AbstractThe beneficial use of computer simulations to track the microstructural evolution of individual species is highlighted in view of macromolecular engineering and design, considering two case studies on catalytic polymerization, and both “low” (<100) and “high” (>100) chain lengths, that is, i) atom transfer radical copolymerization of n‐butyl acrylate and styrene aiming at the synthesis of functional macrospecies of “identical' chain length; and ii) chain shuttling polymerization of ethylene and 1‐octene toward the production of segmented block copolymers with “soft” and “hard” segments. Model parameters are validated and/or tuned based on literature data. The modeling strategy supports the future identification of chemical structure–polymer property relationships and is based on the combination of principles from polymer reaction engineering, chemistry, and physics.
Nanofiber‐Based Hydrogels: Controllable Synthesis and Multifunctional Applications
Authors: Fu Qiuxia , Duan Cheng , Yan Zishuo , Li Yan , Si Yang , Liu Lifang , Yu Jianyong , Ding Bin 
Published: April 2018

AbstractNanofiber‐based hydrogels (NFHGs) prepared by the combination of traditional hydrogels and novel nanofibers have demonstrated great potential in various application fields, owing to their integrated advantages of superhydrophilicity, high water‐holding capacity, good biocompatibility, enhanced mechanical strength, and excellent structural tenability. In this review, a comprehensive overview of the structure design and synthetic strategy of NFHGs derived from electrospinning technique, weaving, freeze‐drying, 3D printing, and molecular self‐assembling method is provided. The widely researched multifunctional applications, primarily involving tissue engineering, drug delivery, sensing, intelligent actuator, and oil/water separation are also presented. Furthermore, some unsolved scientific issues and possible directions for future development of this field are also intensively discussed.
Structure–Property Relations in New Cyclic Galactaric Acid Derived Monomers and Polymers Therefrom: Possibilities and Challenges
Authors: Wróblewska Aleksandra A. , Noordijk Jurrie , Das Nick , Gerards Chris , De Wildeman Stefaan M. A. , Bernaerts Katrien V. 
Published: April 2018

AbstractIn order to fully exploit the potential of carbohydrate‐based monomers, different (and some new) functionalities are introduced on galactaric acid via acetalization, and subsequently, partially‐biobased polyamides are prepared therefrom via polycondensation in the melt. Compared to nonsubstituted linear monomer, faster advancement of the reaction is observed for the different biacetal derivatives of galactaric acid. This kinetic observation is of great significance since it allows conducting a polymerization reaction at lower temperatures than normally expected for polyamides, which allows overcoming typical challenges (e.g., thermal degradation) encountered upon polymerization of carbohydrate‐derived monomers in the melt. The polymers derived from the modified galactaric acid monomers vary in terms of glass transition temperature, thermal stability, hydrophilicity, and functionality.
Self‐Assembly of Rod‐Coil Block Copolymers on Carbon Nanotubes: A Route toward Diverse Surface Nanostructures
Authors: Han Yang , Cai Chunhua , Lin Jiaping , Gong Shuting , Xu Wenheng , Hu Rui 
Published: April 2018

AbstractIn this work, it is reported that poly(γ‐benzyl‐l‐glutamate)‐block‐poly(ethylene glycol) (PBLG‐b‐PEG) rod‐coil block copolymers (BCPs) can disperse carbon nanotubes (CNTs) in solution and form various surface nanostructures on the CNTs via solution self‐assembly. In an organic solvent that dissolves the BCPs, the PBLG rod blocks adsorb on CNT surfaces, and the BCPs form conformal coatings. Then, by the introduction of water, a selective solvent for PEG blocks, the BCPs in the coatings further self‐assemble into diverse surface nanostructures, such as helices (left‐handed or right‐handed), gyros, spheres, and rings. The morphology of the surface nanostructure can be tailored by initial organic solvent composition, preparation temperature, feeding ratio of BCPs to CNTs, degree of polymerization of PBLG blocks, and diameter of the CNTs.
Picophytoplankton size and biomass around equatorial eastern Indian Ocean
Authors: Wei Yuqiu , Sun Jun , Zhang Xiaodong , Wang Jing , Huang Ke 
Published: April 2018

AbstractThe cellular size and biomass of picophytoplankton were studied by flow cytometer during spring monsoon (March–May of 2015) in equatorial eastern Indian Ocean. We established an empirical relationship between forward scatter and cellular size to address the size and biomass of picophytoplankton. Results indicated that mean cell diameter of Prochlorococcus (0.60 μm) was the smallest, and then followed by Synechococcus (0.98 μm) and picoeukaryotic phytoplankton (1.05 μm). Thereafter, the biomass converted by abundance reached 0.64 μg·C·L−1 for Prochlorococcus, 0.34 μg·C·L−1 for Synechococcus, and 0.20 μg·C·L−1 for picoeukaryotic phytoplankton. Additionally, the distinct biomass contribution of picophytoplankton appeared to be affected by abundance, but not changes in cellular size. Vertically, the cellular sizes of picophytoplankton were remarkably small in upper waters, which was predominantly controlled by the nutrient availability. In contrast, they were larger in deeper waters, which was primarily attributed to the combined effects of low temperature and reduced light availability. Spatially, under the influence of high nutrient concentration induced by the different circulations and coastal upwelling, slightly high carbon biomass of picophytoplankton was observed around the coastal zones of Sri Lanka island and Sumatra, as well as the southern Bay of Bengal.
Culture‐independent analysis of hydrocarbonoclastic bacterial communities in environmental samples during oil‐bioremediation
Authors: Dashti Narjes , Ali Nedaa , Salamah Samar , Khanafer Majida , Al‐Shamy Ghada , Al‐Awadhi Husain , Radwan Samir S. 
Published: April 2018

AbstractTo analyze microbial communities in environmental samples, this study combined Denaturing Gradient Gel Electrophoresis of amplified 16S rRNA‐genes in total genomic DNA extracts from those samples with gene sequencing. The environmental samples studied were oily seawater and soil samples, that had been bioaugmented with natural materials rich in hydrocarbonoclastic bacteria. This molecular approach revealed much more diverse bacterial taxa than the culture‐dependent method we had used in an earlier study for the analysis of the same samples. The study described the dynamics of bacterial communities during bioremediation. The main limitation associated with this molecular approach, namely of not distinguishing hydrocarbonoclastic taxa from others, was overcome by consulting the literature for the hydrocarbonoclastic potential of taxa related to those identified in this study. By doing so, it was concluded that the hydrocarbonoclastic bacterial taxa were much more diverse than those captured by the culture‐dependent approach. The molecular analysis also revealed the frequent occurrence of nifH‐genes in the total genomic DNA extracts of all the studied environmental samples, which reflects a nitrogen‐fixation potential. Nitrogen fertilization is long known to enhance microbial oil‐bioremediation. The study revealed that bioaugmentation using plant rhizospheres or soil with long history of oil‐pollution was more effective in oil‐removal in the desert soil than in seawater microcosms.
Construction and application of a Xanthomonas campestris CGMCC15155 strain that produces white xanthan gum
Authors: Dai Xiaohui , Gao Ge , Wu Mengmeng , Wei Weiying , Qu Jianmei , Li Guoqiang , Ma Ting 
Published: April 2018

AbstractIn the industrial production of xanthan gum using Xanthomonas campestris CGMCC15155, large amounts of ethanol are required to extract xanthan gum from the fermentation broth and remove xanthomonadin impurities. To reduce the amount of ethanol and the overall production cost of xanthan gum, a xanthomonadin‐deficient strain of CGMCC15155 was constructed by inserting the Vitreoscilla globin (vgb) gene, under the control of the LacZ promoter, into the region of the pigA gene, which is involved in xanthomonadin synthesis. The insertion of vgb inactivated pigA, resulting in the production of white xanthan gum. The lack of xanthomonadins resulted in a decreased yield of xanthan gum. However, the expression product of vgb gene, VHb, could increase the metabolism of X. campestris, which allowed the production of xanthan gum to reach wild‐type levels in the engineered strain. The yield, molecular weight, and rheological properties of the xanthan gum synthesized by the engineered and wild‐type bacteria were essentially the same. When the same volume of ethanol was used, the whiteness values of the xanthan gum extracted from engineered and wild‐type bacteria were 65.20 and 38.17, respectively. To extract xanthan gum with the same whiteness, three and seven times the fermentation volume of ethanol was required for the engineered and wild‐type strains, respectively. Thus, the engineered train reduced the requirement for ethanol in xanthan gum production by 133.3%. The results demonstrated that the engineered bacteria used less ethanol, thus reducing the downstream processing cost in xanthan gum production.
A nationwide analysis of 30‐day adverse events, unplanned readmission, and length of hospital stay after peripheral nerve surgery in extremities and the brachial plexus
Authors: Martin Enrico , Muskens Ivo S. , Senders Joeky T. , Cote David J. , Smith Timothy R. , Broekman Marike L. D. 
Published: April 2018

BackgroundLittle is known on adverse events and their timing after peripheral nerve surgery in extremities. The aim of this study is to identify predictors and typical timing of complications, unplanned readmission, and length of hospital stay for patients undergoing peripheral nerve surgery in the extremities.MethodsData were extracted from the National Surgical Quality Improvement Program (NSQIP) registry from 2005 to 2015. Adult patients undergoing peripheral nerve surgery in the extremities were included. A subgroup analysis was performed for brachial plexus operations. Multivariable logistic regression was performed to identify predictors of any complication, surgical site infection, unplanned readmission, and reoperation.ResultsA total of 2,840 patients were identified; 628 were brachial plexus operations. Overall complications were 4.4% and 7.0%, respectively. Median time for occurrence of any complication was 8 days. The most common complications were wound‐related (1.7%), which occurred at a median of 15 days postoperatively. Reoperation occurred in 1.8% of all cases; most commonly for musculoskeletal repair (16.7%). Unplanned readmissions occurred in 2.3% and were most often due to wound‐related problems (24.1%). Preoperatively contaminated wounds, inpatient procedures, and longer operative time seemed to have the most influence on all adverse events. In brachial plexus pathology, insulin‐dependent diabetes and emergency cases also negatively affected outcomes.ConclusionsComplications usually occur one to two weeks postoperatively. Preoperatively contaminated wounds, inpatient procedures, and longer operative times influence outcome. Anatomical level of operation results in significantly different lengths of hospital stay; brachial plexus pathology has the longest length of stay.
Asymptotic behavior of the solution of singularly perturbed transmission problems in a periodic domain
Authors: Pukhtaievych Roman 
Published: April 2018

SummaryThis paper is devoted to the study of the asymptotic behavior of the solutions of singularly perturbed transmission problems in a periodically perforated domain. The domain is obtained by making in
a periodic set of holes, each of them of size proportional to a positive parameter ε. We first consider an ideal transmission problem and investigate the behavior of the solution as ε tends to 0. In particular, we deduce a representation formula in terms of real analytic maps of ε and of some additional parameters. Then we apply such result to a nonideal nonlinear transmission problem.
Chlorogenic Acid Protects Against oxLDL‐Induced Oxidative Damage and Mitochondrial Dysfunction by Modulating SIRT1 in Endothelial Cells
Authors: Tsai Kun‐Ling , Hung Ching‐Hsia , Chan Shih‐Hung , Hsieh Pei‐Ling , Ou Hsiu‐Chung , Cheng Yung‐Hsin , Chu Pei‐Ming 
Published: April 2018

ScopeEndothelial dysfunction is an important mechanism in the development of atherosclerosis and is thought to be critical for predicting cardiovascular diseases. Previous reports suggested that chlorogenic acid (CGA) is a potent antioxidant and anti‐inflammatory compound. The molecular mechanisms underlying the inhibitory effects of CGA on oxLDL‐induced oxidative injuries in human endothelial cells are still largely unknown. This study is aimed to test the hypothesis that CGA protects against oxLDL‐facilitated oxidative stress by upregulating SIRT1 and to explore the role of AMPK/PGC‐1 pathway and mitochondrial biogenesis.Methods and resultsHUVECs were treated with oxLDL in the presence or absence of CGA pretreatment. Our data indicated that CGA pretreatment increased SIRT1 deacetylase activity levels. In addition, CGA reversed oxLDL‐impaired SIRT1 and AMPK/PGC‐1 activity and mitigated oxLDL‐induced oxidative stress and dysfunction of mitochondrial biogenesis. However, silencing SIRT1, AMPK, and PGC‐1 abated the ability of CGA to protect against oxidative stress. Results from the present study also suggested that CGA inhibits oxLDL‐induced endothelial apoptosis through modulating SIRT1 and AMPK/PGC‐1 function.ConclusionThese findings provide new insights into possible molecular mechanisms by which CGA mitigates oxLDL‐induced endothelial oxidative stress and mitochondrial dysfunction by activating SIRT1 and modulating the AMPK/PGC‐1 signaling pathway.
Hemodynamic response function (HRF) variability confounds resting‐state fMRI functional connectivity
Authors: Rangaprakash D. , Wu Guo‐Rong , Marinazzo Daniele , Hu Xiaoping , Deshpande Gopikrishna 
Published: April 2018

PurposefMRI is the convolution of the hemodynamic response function (HRF) and unmeasured neural activity. HRF variability (HRFv) across the brain could, in principle, alter functional connectivity (FC) estimates from resting‐state fMRI (rs‐fMRI). Given that HRFv is driven by both neural and non‐neural factors, it is problematic when it confounds FC. However, this aspect has remained largely unexplored even though FC studies have grown exponentially. We hypothesized that HRFv confounds FC estimates in the brain's default‐mode‐network.MethodsWe tested this hypothesis using both simulations (where the ground truth is known and modulated) as well as rs‐fMRI data obtained in a 7T MRI scanner (N = 47, healthy). FC was obtained using 2 pipelines: data with hemodynamic deconvolution (DC) to estimate the HRF and minimize HRFv, and data with no deconvolution (NDC, HRFv‐ignored). DC and NDC FC networks were compared, along with regional HRF differences, revealing potential false connectivities that resulted from HRFv.ResultsWe found evidence supporting our hypothesis using both simulations and experimental data. With simulations, we found that HRFv could cause a change of up to 50% in FC. With rs‐fMRI, several potential false connectivities attributable to HRFv, with majority connections being between different lobes, were identified. We found a double exponential relationship between the magnitude of HRFv and its impact on FC, with a mean/median error of 30.5/11.5% caused in FC by HRF confounds.ConclusionHRFv, if ignored, could cause identification of false FC. FC findings from HRFv‐ignored data should be interpreted cautiously. We suggest deconvolution to minimize HRFv.
Toward in vivo quantification of induced RF currents on long thin conductors
Authors: Griffin Gregory H. , Ramanan Venkat , Barry Jennifer , Wright Graham A. 
Published: April 2018

PurposeMost MR‐guided catheter‐based procedures, and imaging of patients with implanted medical devices, are currently contraindicated due to a significant risk of heating associated with induced RF currents. The induced RF current produces a corresponding artifact which can be used to remotely characterize current and safely predict RF heating. Application of this remote technique in vivo to safely quantify RF heating risk may allow for execution of many scans currently contraindicated. Sources of phase other than induced RF current may present difficulty in practical in vivo.MethodsA custom ultra‐short echo time (UTE) sequence was developed to minimize unwanted phase contributions. A phantom experiment was performed to compare current characterization using a stock gradient‐echo (GRE) sequence and the custom UTE sequence following calibration of the temperature measurement apparatus using a previously published heating prediction technique. Animal experiments were used to investigate the feasibility of using the UTE sequence to quantify RF heating.ResultsCurrent characterization and heating prediction with a stock GRE sequence was equivalent to that with the custom UTE sequence. Heating measurements and image‐based predictions in animal experiments agreed within error in all experiments.ConclusionThrough comparison of measured heating and image‐based prediction, feasibility of using a custom UTE sequence to quantify RF heating risk in vivo was demonstrated.