bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of thermal resistance and mechanical properties of injected molded stereocomplex of poly(l‐lactic acid) and poly(d‐lactic acid) with various molecular weights
Authors: Li Yuzeng , Li Qiao , Yang Gesheng , Ming Ruihao , Yu Minmin , Zhang Huihui , Shao Huili 
Published: March 2017

AbstractPoly(l‐lactic acid) (PLLA) and poly(d‐lactic acid) (PDLA) with various molecular weights (MW) were melt blended in equivalent proportions, and then followed by injection molding to form polylactide stereocomplex (sc‐PLA). The crystalline structures, thermal resistance, and mechanical properties of the formed sc‐PLA were then investigated in detail. The results showed stereocomplex crystallites (sc) were formed predominantly in all the sc‐PLA regardless of the MW of the PLLA or PDLA pellets, and a small amount of homocrystallites (hc) also coexisted in sc‐PLA. The MW of PLLA and PDLA pellets displayed significant effects on the crystallinity, thermal resistance, and mechanical properties of sc‐PLA. PLLA and PDLA with low and similar MW facilitated the formation of sc, and also improved the onset degradation temperature and Vicat softening temperature of sc‐PLA. For a similar degree of crystallinity, high MW was found to be more favorable in improving the thermal performance of sc‐PLA. Although sc‐PLA prepared from PLLA and PDLA with low MW showed decreased mechanical properties, the mechanical properties of sc‐PLA increased with an increase in the MW of the PLLA or PDLA pellet. When PLLA and PDLA pellets with high and similar MW were used, the mechanical properties of sc‐PLA could even exceed those of pure PLLA.
Effect of amphoteric dispersant on the dispersion properties of nano‐SiO2 particles
Authors: Gao Rui‐Jun , Yao Yan , Wu Hao , Wang Ling 
Published: March 2017

ABSTRACTAn amphoteric polycarboxylate dispersant (APC) was synthesized by copolymerization of acrylic acid (AA), methacryloxyethyltrimethyl ammonium chloride (DMC), and isopentenol polyoxyethylene ether (IPEG). The molecular structure of APC was characterized by FT‐IR, 1H‐NMR, and GPC. Effect of the dosage of APC on the rheological performance of nano‐SiO2 suspension was investigated by measurements of the plastic viscosity. The results indicated that the best dispersion effect of APC was obtained when the dosage of APC was about 10 wt % (by the weight percent of nano‐SiO2), which can maintain the dispersion of nano‐SiO2 suspension uniformly for 4 h without settlement. Meanwhile, the zeta potential value on the surface of nano‐SiO2 particles shows that the better dispersion performance of APC was attributed to the solvation water film formed by the polyoxyethylene side chains and the electrostatic repulsion formed by positively groups (CN+) on the APC structure combined with ‐SiO– groups on the surface of nano‐SiO2 particles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45075.
Direct solid state polycondensation of tetra‐ and hexa‐methylenediammonium terephthalate: Scaling up from the TGA micro‐reactor to a laboratory autoclave
Authors: Porfyris Athanasios D. , Papaspyrides Constantine D. , Rulkens Ruud , Grolman Eric 
Published: March 2017

ABSTRACTThe direct solid state polycondensation (DSSP) reaction of tetramethylenediammonium and hexamethylenediammonium terephthalate (4 T and 6 T salts) in a laboratory scale autoclave reactor was investigated. The autoclave reactor is 3 orders of magnitude larger than the TGA micro‐reactor we used previously. The larger scale reactor allows more extensive analyses such as analysis of the formed condensate by titration and allows investigation of operating conditions that are important on industrial scale, such as batch (closed system) versus semibatch (open system) operation and flow of nitrogen used. Comparing the two scales has given important insight into the parameters that are important in scaling‐up direct solid‐state polycondensation. Furthermore, the effect of scaling up on the quality of the final semiaromatic polyamide products was determined, by comparing the obtained thermal properties, the solution viscosity and the end‐group concentrations obtained by 1H‐NMR spectroscopy. When operating the open reactor with a gentle nitrogen stream, the results show that products of similar properties were obtained from the micro and the laboratory scale reactors if critical parameters like temperature and pressure time profile were kept the same. The solid character of the reacting mass was retained only when maintaining the reactor at atmospheric pressure, allowing the condensation water to be removed. When keeping the autoclave reactor closed, both polyamide (PA) products (i.e., PA4T and PA6T) were agglomerated as a result of a solid melt transition during the direct solid state polycondensation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45080.
Piecemeal Mechanism Combining Sprouting and Intussusceptive Angiogenesis in Intravenous Papillary Formation Induced by PGE2 and Glycerol
Authors: Díaz‐Flores Lucio , Gutiérrez Ricardo , García M. Del Pino , Sáez Francisco J. , Díaz‐Flores Lucio , Madrid Juan F. 
Published: March 2017

ABSTRACTRecently, we demonstrated that in human intravascular papillary endothelial hyperplasia (IPEH), vein wall vascularization occurs in association with myriad papillae, a large part of which formed in the vascularized vein wall. Previously, using an animal model, we observed that PGE2 and glycerol administration around the femoral vein originates intense vascularization of the vein wall from its intimal endothelial cells (ECs). This vascularization is similar to that in IPEH. The aim of this study is to assess the mechanism of papillary formation, using this model after demonstrating papillary development in neo‐vascularized femoral vein walls. In semithin and ultrathin sections, the sequential vascular and papillary development was as follows: (a) activation of vein intimal ECs, (b) sprouting of intimal ECs towards the vein media layer and microvessel development, (c) interconnection between neighboring microvessels originated elementary loops, which encircled vein wall components and formed papillae. The encircling ECs formed the papillary cover, and the encircled component formed the core. The papillae showed a similar structure to that of folds and pillars in intussusceptive angiogenesis, and (d) origin of secondary and complex loop systems by interconnection of neighboring elementary loops and by splitting of papillae by new loops, with abundant papillary development. In conclusion, the results support a piecemeal angiogenic mechanism in papillary formation, with association of sprouting and intussusceptive types of angiogenesis. Further studies are needed to assess whether the intravascular papillae described in several pathologic processes, including vessel tumors, such as Dabska's tumor, retiform hemangioendothelioma, and angiosarcoma, follow a similar mechanism. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1781–1792, 2017. © 2017 Wiley Periodicals, Inc.
High Ratios of C20:4n‐6/C20:5n‐3 and Thromboxane B2/6‐Keto‐Prostaglandin F1α in Placenta Are Potential Risk Contributors for Neural Tube Defects: A Case–Control Study in Shanxi Province, China
Authors: Li Kelei , Zhang Xiaotian , Pei Lijun , Chen Gong , Liu Jianmeng , Wahlqvist Mark L. , Zheng Xiaoying , Li Duo 
Published: March 2017

BackgroundNeural tube defects (NTDs) are severe congenital malformations. Folate supplementation can reduce the risk, but cannot prevent all NTDs, suggesting other reasons for folate‐resistant NTDs. The present study assesses placental fatty acid composition, eicosanoids, and cytokines as risk factors for NTDs in a Chinese population with highly incident NTDs.MethodsSeventy‐seven aborted fetuses with NTDs during the third trimester were cases and 142 healthy newborns were controls. Placental fatty acid composition, eicosanoids, and cytokines were determined by standard methods.ResultsThe placental C20:4n‐6/C20:5n‐3 and thromboxane B2 (TXB2)/6‐keto‐prostaglandin F1α (6‐keto‐PGF1α) ratios were significantly higher for cases than controls (p < 0.001 and 0.05, respectively). For the top versus the lowest tertiles of placental C20:4n‐6/C20:5n‐3 and TXB2/6‐keto‐PGF1α, odds ratios for NTD occurrence were 3.79 (95% confidence interval, 1.60–8.96) (p for trend < 0.01) and 5.52 (95% confidence interval, 2.07–14.74) (p for trend < 0.001), respectively, adjusted for fetal sex as well as maternal age, occupation, parity, smoking, passive smoking, periconceptional folate supplementation, conception season, and tea drinking. The C20:4n‐6/C20:5n‐3 and TXB2/6‐keto‐PGF1α ratios were positively correlated (r = 0.14; p < 0.05). The proportions of C18:2n‐6, C18:3n‐6, C20:3n‐6, C18:3n‐3, C20:3n‐3, C20:5n‐3, and C22:5n‐3 were significantly lower in cases than controls, and all negatively associated with NTD occurrence (tertile‐specific odds ratios); after adjustment for the potential confounders, these associations remained significant (p for trend < 0.05) except for C20:3n‐3.ConclusionHigh placental ratios of C20:4n‐6/C20:5n‐3 and TXB2/6‐keto‐PGF1α are risk factors for neural tube defects.Birth Defects Research 109:550–563, 2017.© 2017 Wiley Periodicals, Inc.
Gestational and Lactational Exposure to an Environmentally‐Relevant Mixture of Brominated Flame Retardants: Effects on Neurodevelopment and Metabolism
Authors: Tung Emily W. Y. , Kawata Alice , Rigden Marc , Bowers Wayne J. , Caldwell Don , Holloway Alison C. , Robaire Bernard , Hales Barbara F. , Wade Michael G. 
Published: March 2017

BackgroundDevelopmental exposure to brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD), has been associated with impaired neurodevelopment and some symptoms of metabolic syndrome. However, there are inconsistencies in studies reporting neurodevelopmental effects with studies of pure substances more likely to report effects than studies of technical products. In addition, the influence of early BFR exposures on later development of metabolic disease‐like symptoms has not been investigated. This study examined the effects of perinatal exposure to an environmentally relevant mixture of BFRs based on relative levels observed in house dust, on several markers of neurodevelopment and metabolism in offspring.MethodsSprague–Dawley female rats were fed a diet estimated to deliver daily doses of 0, 0.06, 20, or 60 mg/kg of a mixture of PBDEs and HBCDD from before mating to weaning. Offspring were weaned to control diet and subjected to neurobehavioral and metabolic assessments.ResultsExposure to BFRs decreased vertical movement in at postnatal day (PND) 32 and increased time to emerge to a lighted area on PND 105 in offspring of both sexes. Although early life exposure to the BFR mixture did not impact measures of glucose or insulin action, male offspring had significantly decreased fat pad weights at PND 46. Total cholesterol was increased in male and female offspring exposed to the highest dose at PND 21.ConclusionsThese results suggest that gestational and lactational exposure to an environmentally relevant BFR mixture may induce changes in neurodevelopment and lipid metabolism in offspring. Birth Defects Research 109:497–512, 2017.© 2017 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.
Evaluating the quality of implantation of percutaneous ventricular restoration device (Parachute®) by cardiac computed tomography
Authors: Alaiti Mohamad Amer , Fares Anas , Erglis Andrejs , Nshisso Lemba , Shaikh Kashif , DeCicco Anthony E. , Nasif Marwan , Alkhalil Ahmad , Ince Hüseyin , Abraham William T. , Simon Daniel I. , Costa Marco A. , Attizzani Guilherme F. , Bezerra Hiram G. 
Published: March 2017

BackgroundThe Parachute is a novel percutaneously implanted ventricular partitioning device (VPD) that has emerged as a safe and feasible treatment option for patients with heart failure following anterior wall myocardial infarction. VPD efficacy is likely dependent on optimal device placement, but to date there are no published data examining the effect of device positioning on patient outcomes.Methods and resultsWe retrospectively identified 32 patients successfully implanted with the Parachute device, all of whom underwent cardiac computed tomography (CCT) at baseline and after 6 months of follow‐up. Patients were divided into two groups based on self‐reported improvement in New York Heart Association (NYHA) functional class: “not improved NYHA” (n = 12) and “improved NYHA” (n = 20). There were significant differences between both groups with regard to device positioning on follow‐up CCT. Compared to patients with “improved NYHA,” patients with “not improved NYHA” had longer distances from device foot to left ventricular apex (8.0 ± 4.9 vs. 2.9 ± 4.6 mm; P = 0.01), and higher lateral angles (18.0 ± 14 vs. 9.1 ± 6.8 degrees; P = 0.02), respectively. There was no significant difference between the two groups in landing zone (45.4 ± 7. vs. 45.1 ± 6.9 mm; P = 0.92) and inferior angle (14.0 ± 11.9 vs. 14.3 ± 10.1 degrees; P = 0.95). There was a numerically larger malapposition area in the “not improved NYHA” group (5.1 ± 4.5 vs. 3.2 ± 2.2 cm2; P = 0.12).ConclusionQuality of Parachute implant impacted clinical outcome, these findings should be applied prospectively in helping operators to achieve optimal implant. © 2016 Wiley Periodicals, Inc.
Coronary artery bifurcation narrowing treated by Axxess stent implantation: The CARINAX registry
Authors: Briguori Carlo , Donahue Michael , Visconti Gabriella , Focaccio Amelia , Pennacchi Mauro , Lucisano Luigi , Stio Rocco , Mancone Massimo , Calcagno Simone , Di Palma Vito , Labalestra Nicola , Signoriello Giuseppe , Sardella Gennaro 
Published: March 2017

ObjectivesTo compare the safety and efficacy of the Axxess™ biolimus‐eluting stent with the second‐generation drug‐eluting stent (DES) in the treatment of bifurcation lesions.BackgroundThe Axxess™ is a dedicated bifurcation stent, designed to cover the lesion at the carina level.MethodsBetween April 2012 and August 2014, 165 patients with de novo bifurcation lesions were treated with the Axxess™ stent (Axxess group). A propensity‐score matched group of 165 patients treated with DES in the same period was selected (Control group). The primary objectives were (1) the procedural complication rate, including side branch (SB) occlusion and trouble in SB access after main vessel stenting; and (2) the device, the angiographic, and the procedural success rate.ResultsProcedural complications occurred in 1 patient (0.6%) in the Axxess group and in 20 patients (12%) in the Control group (OR = 0.03; 95% confidence interval 0.005–0.27; P < 0.001). Device success was obtained in 164 (99.5%) patients in the Axxess group and in all in the Control group (P = 1.00). Angiographic success was obtained in all patients. Inaccurate Axxess™ stent position occurred in 21 (13%) patients, and was more often associated with moderate‐to‐severe calcifications and distal lesion site. Procedural success was obtained in 91.5% patients in the Axxess group and in 90% patients in the Control group (P = 0.72).ConclusionsThe present registry suggests that the Axxess™ stent (1) may represent a valid alternative approach for the treatment of bifurcation lesions and (2) should be avoided in moderate‐to‐severe calcifications and/or in distal lesions. © 2016 Wiley Periodicals, Inc.
Non‐cardiac surgery after PCI: Watch out for complex lesions
Authors: Belardi Jorge A. , Albertal Mariano 
Published: March 2017

Key Points

Patients who undergo non‐cardiac surgery after percutaneous coronary interventions (PCI) carry a risk of major adverse cardiac events.
Certain angiographic characteristics of the treated lesions increase the risk of non‐cardiac surgery at follow‐up: ostial, distal, and/or calcified lesions. The adjunctive use of intravascular imaging may guarantee an optimal result in these lesions and reduce their long‐term risk.
Left main or left anterior descending locations as well as the treatment of chronic total occlusion did not influence non‐cardiac surgical risk.
Low rate fluoroscopy in cardiac catheterization: Toward a new standard?
Authors: Plourde Guillaume , Bertrand Olivier F. 
Published: March 2017

Key Points

7.5 frames/s low‐rate fluoroscopy (LRF) is an effective measure to reduce patient radiation exposure during coronary procedures
LRF should now be widely integrated into clinical practice as part of a dose reduction program
Further evaluation of low‐rate cine acquisition could potentially reduce radiation exposure to a greater extent
Patent ductus arteriosus and pulmonary arterial hypertension: Is it closer to closure?
Authors: Parekh Dhaval , Krajcer Zvonimir 
Published: March 2017

Key Points

Occlusion of large patent ductus arteriosus (PDA) with elevated pulmonary pressures can be considered in patients with left‐to‐right shunting and low resistance as evidenced by LV enlargement on echocardiography.
High technical and procedural success was achieved without incurring major complications: embolization, hemolysis, residual shunt, or adjacent pulmonary or aortic impingement.
The Occlutech® PDA occluder may be well suited for treating large PDA given its shape, flexibility, and available large sizes. Its enlarged pulmonary end and aortic retention skirt may allow increased stability with less oversizing in patients with elevated pulmonary pressures.
Does the removal of the temporary pacer wire for BAV and TAVR really simplify the procedure?
Authors: Steinvil Arie , Satler Lowell 
Published: March 2017

Key Points

Temporary wire pacing (TWP) involving a separate right ventricular (RV) pacing electrode during balloon aortic valvuloplasty (BAV) and transcatheter aortic valve replacement (TAVR), is effective for both BAV and TAVR stability during deployment. Hilling‐Smith et al. describe their experience on 208 TAVR and BAV patients using the left ventricular (LV) support guidewire instead of the separate RV pacing electrode.
The need for intraprocedural TWP during TAVR occurred in 5% of patients with the LV support guidewire, with an overall 21% need of PPM during the index hospitalization. No events were demonstrated during BAV procedures.
LV pacing with the support guidewire is feasible. The intraprocedural need for pacing and a 48‐hr observation period probably limit its use in TAVR. In BAV it can be considered as an alternative pacing strategy.
Transcatheter aortic valve replacement by a minimalist approach: A breath of fresh air for patients with chronic obstructive pulmonary disease
Authors: Caixeta Adriano , Lemos Pedro A. 
Published: March 2017

Key Points

A minimalist approach to transcatheter aortic valve replacement in selected patients results in shorter hospitalization and may improve short‐ and long‐term survival compared to a standard approach
Minimalist TAVR can be performed with less or no intensive care unit support leading to a shorter hospitalization and improved resource utilization
Diligent patient selection by the heart team and thorough education of the entire care staff are the keys to success for minimalist TAVR
Ring‐Opening Copolymerization of Epoxides with Cyclic Anhydrides Promoted by Bimetallic and Monometallic Phenoxy–Imine Aluminum complexes
Authors: Isnard Florence , Lamberti Marina , Pellecchia Claudio , Mazzeo Mina 
Published: March 2017

AbstractTwo dinuclear aluminum alkyl complexes bearing a salen ligand with alkyl backbone of different length between the nitrogen atoms (1,3‐propylene and 1,5‐pentylene backbone) and the related hemisalen aluminum complex were tested as catalysts in the ring‐opening copolymerization of cyclohexene oxide and limonene oxide with succinic anhydride and phthalic anhydride. The effects of different reaction conditions (co‐catalyst and solvent) on the productivity and selectivity of the reactions were evaluated. The comparison of the catalytic behavior of the dinuclear complexes bearing the aluminum reactive centers at different distances as well as of their mononuclear counterpart suggested that the copolymerization follows a monometallic pathway differently from what was observed in the homopolymerization of CHO.
Composites of Piezoelectric Materials and Silicon as Anodes for Lithium‐Ion Batteries
Authors: Wang Zhiguo , Li Zhijie , Fu Yong Qing 
Published: March 2017

AbstractGroup IVA elements (Si, Ge, and Sn) are promising candidates for the anode materials of lithium‐ion batteries (LIBs), owing to their large theoretical specific capacities. However, serious problems of pulverization and capacity degradation resulting from the huge volume changes during charge/discharge operations have hindered their successful applications as anode materials in LIBs. In this work, the diffusion behaviors of Li ions in Si(100) and Si(111) slabs with a piezoelectric field applied perpendicularly to the surfaces were investigated by using density functional theory. The results show that the diffusivity of Li in Si can be significantly enhanced by applying the electric field generated from the piezoelectric material. This finding can explain the recent experimental observations, in which an improved electrochemical performance was obtained by using Si/carbon nanotube/BaTiO3 as the anode of a LIB. A new generation of anode composite materials can be designed based on this idea and the piezoelectric material is used not only to accommodate the volume variation of active materials of Si, but also to enhance the charging rate of the LIBs.
Self‐Assembled Manganese Sulfide Nanostructures on Graphene as an Oxygen Reduction Catalyst for Anion Exchange Membrane Fuel Cells
Authors: Arunchander Asokan , Peera Shaik Gouse , Sahu Akhila Kumar 
Published: March 2017

AbstractThe development of active, inexpensive, and durable non‐precious‐metal electrocatalysts to replace high‐cost Pt‐based catalysts towards the commercialization of fuel cell technology is the focus in recent years. In this regard, we report a facile one‐pot hydrothermal synthesis of self‐assembled manganese sulfide on graphene layers (MnS/G), and is recognized as a non‐precious‐metal catalyst for the efficient oxygen reduction reaction (ORR) in an alkaline medium. The phase purity and surface morphologies are investigated by using X‐ray diffraction and scanning electron microscopic techniques, respectively. Optimized MnS/G with 50 % Mn exhibited excellent ORR properties with onset and half‐wave potentials of 0.83 and 0.71 V vs. RHE, respectively. While evaluating the durability, only a 90 mV negative shift in its half‐wave potential is observed after 5000 repeated potential cycles, which is also ascertained for up to 48 h of operation at a constant potential by using a chronoamperometric technique with 28 % degradation in the current. The optimized material is utilized as a cathode catalyst in fabricating membrane electrode assembly for performance evaluation in an anion exchange membrane fuel cell. A peak power density of 12 mW cm−2 is realized in H2−O2 feeds under ambient temperature and pressure; thus, it looks as an alternative non‐precious‐metal catalyst for fuel cell applications.