bluuebunny/crossref_metadata_2025 huggingface dataset:
Resorbable plating system stabilizes tissue‐engineered intervertebral discs implanted ex vivo in canine cervical spines
Authors: Mojica‐Santiago Jorge A. , Lang Gernot M. , Navarro‐Ramirez Rodrigo , Hussain Ibrahim , Hӓrtl Roger , Bonassar Lawrence J.
Published: August 2018

Total disc replacement using tissue‐engineered intervertebral discs (TE‐IVDs) may offer a biological alternative to treat radiculopathy caused by disc degeneration. A composite TE‐IVD was previously developed and evaluated in rat tail and beagle cervical spine models in vivo. Although cell viability and tissue integration into host tissue were promising, significant implant displacement occurred at multiple spinal levels. The goal of the present study was to assess the effects of a resorbable plating system on the stiffness of motion segments and stability of tissue‐engineered implants subjected to axial compression. Canine motion segments from levels C2/C3 to C5/C6 were assessed as intact (CTRL), after discectomy (Dx), with an implanted TE‐IVD only (PLATE−), and with a TE‐IVD combined with an attached resorbable plate (PLATE+). Segments under PLATE+ conditions fully restored separation between endplates and showed significantly higher compressive stiffness than segments under PLATE− conditions. Plated segments partially restored more than 25% of the CTRL motion segment stiffness. Plate attachment also prevented implant extrusion from the disc space at 50% compressive strain, and this effect was more significant in segments from levels C3/C4 when compared to segments from level C5/C6. These results suggest that stabilization of motion segments via resorbable plating assists TE‐IVD retention in the disc space while allowing the opportunity for implants to fully integrate into the host tissue and achieve optimal restoration of spine biomechanics.
Investigating value added from heritage assets: An analysis of landmark historical sites in Wales
Authors: Beynon Malcolm J. , Jones Calvin , Munday Max , Roche Neil
Published: August 2018

We reveal how tourist visitation to similar historical sites supports different levels of local gross value added (GVA). The paper shows how information on tourism activity at few historical sites can be used to analyse causal recipes defining whether sites support relatively high/low levels of GVA. Fuzzy‐set qualitative comparative analysis is employed to offer perspectives not possible with other analytical methods. The study reveals that for a set of similar heritage sites, that factors supporting local economic impacts are complex and with this having ramifications for management interventions around sites that seek to boost the economic impacts of visitation.
Genetic structure and recovery of white‐tailed deer in Missouri
Authors: Budd Kris , Berkman Leah K. , Anderson Michelle , Koppelman Jeff , Eggert Lori S.
Published: August 2018

The white‐tailed deer (Odocoileus virginianus) of Missouri have undergone changes in the past 100 years. From a historical estimate of 700,000 individuals, deer were nearly extirpated from the state following overexploitation in the late 1800s. Despite this, deer have since undergone a rapid expansion to the current population of 1.4 million. Because of this complex recent history, we sought to understand the levels and distribution of genetic diversity in deer across Missouri. We genotyped 751 deer at 10 microsatellite loci and used genetic distance metrics and Bayesian clustering analyses to identify distinct genetic groups. We also sequenced the mitochondrial control region from a subset (n = 248) of deer to identify historical lineages. We found high levels of nuclear marker diversity (HE = 0.818) and low, but statistically significant, levels of differentiation among regions. The high level of mitochondrial diversity (48 haplotypes; haplotype diversity = 0.621–0.964) is reflected in a haplotype network that suggests the persistent signature of translocated lineages. Overall, the white‐tailed deer of Missouri now represent a highly diverse population with no indication that there are barriers to gene flow. This will be an important consideration for the management of disease resistance and spread throughout the state. © 2018 The Wildlife Society.
Refusal of Cancer‐Directed Surgery in Head and Neck Squamous Cell Carcinoma Patients
Authors: Crippen Meghan M. , Elias Marcus L. , Weisberger Joseph S. , Brady Jacob S. , Eloy Jean Anderson , Baredes Soly , Park Richard Chan Woo
Published: August 2018

Objectives/Hypothesis

To investigate the risk factors for refusal of recommended surgery in head and neck squamous cell carcinoma (HNSCC) treatment

Study Design

Retrospective review of a national database.

Methods

The Surveillance, Epidemiology, and End Results database was queried for all cases of HNSCC from 1989 to 2014. Patients who underwent recommended surgery (N = 98,270) were identified and compared to patients who refused recommended surgery (N = 3,582). Groups were compared for patient demographics, socioeconomic variables, and tumor characteristics including stage, grade, and primary site. Binary logistic regression was performed to determine independent predictors of surgery refusal.

Results

Of the total population, 1.8% of patients refused cancer directed surgery. Following regression, the strongest predictors of surgery refusal were found to be age greater than 75years (odds ratio [OR]: 4.23 [95% confidence interval {CI}: 3.00‐5.96]), and stage III (OR: 4.19 [95% CI: 3.15‐5.57]) or stage IV at diagnosis (OR: 4.49 [95% CI: 3.46‐5.80]). Black race was significantly predictive (OR: 1.71 [95% CI: 1.37‐2.13]) as well as marital status other than married (OR: 1.76 [95% CI: 1.49‐2.07]) and Medicaid insurance status (OR:1.46 [95% CI: 1.20‐1.77]). Primary site of larynx (OR: 2.01 [95% CI: 1.71‐2.37]) or base of tongue (OR: 2.34 [95% CI: 1.87‐2.92]) additionally predicted surgery refusal.

Conclusions

A number of demographic, socioeconomic, and tumor‐related variables are associated with refusal of cancer‐directed surgery in head and neck squamous cell carcinoma. Recognition of these factors may help identify situations where more active education and support are needed to help patients accept optimal care.

Level of Evidence

4

Laryngoscope, 129:1368–1373, 2019
Reaction Specificity of Phospholipase D Prepared from Acinetobacter radioresistens a2 in Transphosphatidylation
Authors: Cao Kewei , Liu Yanjun , Tian Yingying , Zhang Qin , Cong Peixu , Li Hongyan , Xu Jie , Li Zhaojie , Wang Jingfeng , Mao Xiangzhao , Xue Changhu
Published: August 2018

Phospholipase D (PLD) can react with phospholipids as substrates, generally phosphatidylcholine (PtdCho), and the PLD‐substrate intermediate can be cleaved by another alcohol, resulting in transphosphatidylation of the substrate, which can be used in the production of special lipids. In this study, the reaction conditions affecting the transphosphatidylation of PtdCho with serine were optimized and the reaction specificity of a novel PLD prepared from Acinetobacter radioresistens a2 was evaluated for transphosphatidylation with a variety of phospholipid substrates and head group donors. Based on the yield of phosphatidylserine, experimental kinetic data, maximum transphosphatidylation rate, and kinetic constant, the specificity of PLD in transphosphatidylation was found to be affected by unsaturated fatty‐acid phospholipid substrates. The catalytic efficiency of PLD prepared from A. radioresistens a2 on the synthesis of natural phospholipids is on the order of l‐serine > ethanolamine and glycerol ≫ inositol. Moreover, it was found that the transphosphatidylation of PtdCho with saccharides was related to the length of the carbon chain and the number of saccharide units.
On the canonical embedding of a JB*‐triple into its bidual
Authors: Isidro José M.
Published: August 2018

We prove that the canonical embedding of a JB*‐triple E into its bidual extends uniquely to a manifold embedding between the corresponding real Banach Lie groups of holomorphic automorphisms of their respective open unit balls and , the image being a closed (though not a direct) Lie subgroup of .
Synthesis of Polyfluoro Arylene‐Based Poly(arylenevinylene)s via Pd‐Catalyzed Dehydrogenative Direct Alkenylation
Authors: Saito Hitoshi , Kuwabara Junpei , Yasuda Takeshi , Kanbara Takaki
Published: August 2018

In this study, π‐conjugated poly(arylenevinylene)s are synthesized via the Pd‐catalyzed dehydrogenative direct alkenylation of polyfluoroarenes with diethenyl aromatic monomer. The introduction of a fluoro group promotes the cross‐coupling reaction, and the formation of the undesired homocoupling byproduct is minimized by optimizing the reaction conditions. The polycondensation reactions lead to the formation of poly(arylenevinylene)s with a well‐defined trans‐configuration. The obtained polymers are evaluated as emitting materials for organic light‐emitting diodes.
Incorporation of Metallic Species into Midblock‐Sulfonated Block Ionomers
Authors: Deng Jing , Yan Jiaqi , Tilly Joseph C. , Deng Liyuan , Mineart Kenneth P. , Spontak Richard J.
Published: August 2018

Block ionomers can, in the same fashion as their neutral block copolymer analogs, microphase‐order into various nanoscale morphologies. The added benefit of a copolymer possessing a charged species is that the resultant block ionomer becomes amphiphilic and capable of imbibing polar liquids, including water. This characteristic facilitates incorporation of metallic species into the soft nanostructure for a wide range of target applications. In this study, the nonpolar and polar constituents of solvent‐templated midblock‐sulfonated block ionomers (SBIs) are first selectively metallated for complementary morphological analysis. Next, four different salts, with cationic charges ranging from +1 to +3, are introduced into three hydrated SBIs varying in their degree of sulfonation (DOS), and cation uptake is measured as a function of immersion time. These results indicate that uptake generally increases with increasing salt concentration, cationic charge, and specimen DOS. Swelling and nanoindentation measurements conducted at ambient temperature demonstrate that water uptake decreases, while the surface modulus increases, with increasing cationic charge. Chemical spectra acquired from energy‐dispersive X‐ray spectroscopy (EDS) confirm the presence of each of the ion‐exchanged species, and corresponding EDS chemical maps reveal that the spatial distribution of these species is relatively uniform throughout the block ionomer films.
The diffusive Beddington‐DeAngelis predator‐prey model with nonlinear prey‐taxis and free boundary
Authors: Wang Jianping , Wang Mingxin
Published: August 2018

The diffusive Beddington‐DeAngelis predator‐prey model with nonlinear prey‐taxis and free boundary is considered. We investigate the existence, uniqueness, regularity, uniform estimates, and long‐time behavior of the global solution. Some sufficient conditions for both spreading and vanishing are also established. To our best knowledge, this is the first work concerning the dynamics of the cross‐diffusion systems with free boundaries.
Tracing scientific reasoning in psychiatry: Reporting of statistical inference in abstracts of top journals 1975–2015
Authors: Baethge Christopher , Deckert Markus , Stang Andreas
Published: August 2018

Objective

To analyze the reporting of statistical inference in psychiatry.

Method

We searched 63,928 abstracts, published in 15 leading psychiatric journals (1975–2015).

Results

Median abstract length increased from 664 (1975) to 1,323 (2015) characters, and median use of numbers from two to 14/abstract. A total of 3.6% of all abstracts exclusively contained significance terminology in a nonstatistical sense, and 45% showed some form of statistical inference, increasing from 26% to 52%. In those abstracts, statistical inference based on thresholds was dominant. Its proportion decreased from 99% to 66%, but with rising numbers of articles, figures rose from 1,095 to 2,382. Although reporting p values without thresholds did not appear 40 years ago and remains rare, combining precise p values with thresholds is now common. In 2010–2015, 86% of abstracts contained p values or p value thresholds, 22% confidence intervals, and 7% confidence intervals only. Results varied across journals.

Conclusion

There is a moderate shift from reporting p values along set thresholds, such as p ≤ 0.05, to presenting precise p values and confidence intervals, but not as pronounced as in epidemiology and general medicine. The long debate on estimation over testing has not led to a substantial replacement of p values by confidence intervals. Null hypothesis testing (“p ≤ .05”) dominates statistical thinking.
Accelerating compressed sensing in parallel imaging reconstructions using an efficient circulant preconditioner for cartesian trajectories
Authors: Koolstra Kirsten , van Gemert Jeroen , Börnert Peter , Webb Andrew , Remis Rob
Published: August 2018

Purpose

Design of a preconditioner for fast and efficient parallel imaging (PI) and compressed sensing (CS) reconstructions for Cartesian trajectories.

Theory

PI and CS reconstructions become time consuming when the problem size or the number of coils is large, due to the large linear system of equations that has to be solved in
and
‐norm based reconstruction algorithms. Such linear systems can be solved efficiently using effective preconditioning techniques.

Methods

In this article we construct such a preconditioner by approximating the system matrix of the linear system, which comprises the data fidelity and includes total variation and wavelet regularization, by a matrix that is block circulant with circulant blocks. Due to this structure, the preconditioner can be constructed quickly and its inverse can be evaluated fast using only two fast Fourier transformations. We test the performance of the preconditioner for the conjugate gradient method as the linear solver, integrated into the well‐established Split Bregman algorithm.

Results

The designed circulant preconditioner reduces the number of iterations required in the conjugate gradient method by almost a factor of 5. The speed up results in a total acceleration factor of approximately 2.5 for the entire reconstruction algorithm when implemented in MATLAB, while the initialization time of the preconditioner is negligible.

Conclusion

The proposed preconditioner reduces the reconstruction time for PI and CS in a Split Bregman implementation without compromising reconstruction stability and can easily handle large systems since it is Fourier‐based, allowing for efficient computations.
Yield design‐based numerical analysis of three‐dimensional reinforced concrete structures
Authors: Vincent Hugues , Arquier Mathieu , Bleyer Jérémy , de Buhan Patrick
Published: August 2018

The objective of this contribution is to present some new recent developments regarding the evaluation of the ultimate bearing capacity of massive three‐dimensional reinforced concrete structures which cannot be modeled as 1D (beams) or 2D (plates) structural members. The approach is based upon the implementation of the lower bound static approach of yield design through a discretization of the three‐dimensional structure into tetrahedral finite elements, on the one hand, the formulation of the corresponding optimization problem in the context of semi‐definite programming techniques, on the other hand. Another key feature of the method lies in the treatment of the concrete‐embedded reinforcing bars not as individual elements, but by resorting to an extension of the yield design homogenization approach. The whole procedure is first validated on the rather simple illustrative problem of a uniformly loaded simply supported beam, then applied to the design of a bridge pier cap taken as an example of more complex and realistic structure.
Efficient budget allocation strategies for elementary effects method in stochastic simulation
Authors: Shi Wen , Chen Xi
Published: August 2018

This paper focuses on extending the Morris' elementary effects method (MM) for sensitivity analysis/factor screening originated in the context of deterministic computer experiments to the stochastic simulation setting. Given a fixed simulation budget to expend, the main objective is to provide efficient and accurate estimates of main and interaction (or nonlinear) effects coined by the standard MM for characterizing the importance of each factor, despite the impact of simulation errors. Taking into account both the factor/input sampling uncertainty rooted in MM and the random errors inherent in a stochastic simulation, we develop efficient budget allocation strategies for implementing MM in this new context. Under each strategy proposed, we derive its corresponding optimal budget partition and optimal budget allocation rules. Numerical results corroborate the practical effectiveness of the proposed budget allocation strategies.
Prognostic Value of the ESPEN Consensus and Guidelines for Malnutrition: Prediction of Post‐Discharge Clinical Outcomes in Older Inpatients
Authors: Sánchez‐Rodríguez Dolores , Annweiler Cédric , Ronquillo‐Moreno Natalia , Vázquez‐Ibar Olga , Escalada Ferran , Duran Xavier , Muniesa Josep M. , Marco Ester
Published: August 2018

Introduction

Our study aimed to determine whether malnutrition and nutrition‐related conditions using the European Society for Clinical Nutrition and Metabolism (ESPEN) consensus were associated with functional status, institutionalization, readmissions, and mortality in older patients at 3‐month follow‐up.

Methods

A cohort of 102 consecutive deconditioned patients was assessed at 3 months postdischarge from postacute geriatric care. Inclusion criteria were age ≥70 years, scores of Mini‐Mental Status Examination ≥21/30, and being admitted for rehabilitation after an acute non‐disabling disease. Malnutrition as defined by ESPEN consensus and nutrition‐related conditions (such as frailty, sarcopenia, overweight/obesity, nutrient deficiency, and cachexia) was assessed, and related to postdischarge clinical outcomes at 3‐month follow‐up.

Results

Of 95 included patients (84.5 ± 6.5 years; 63.2% women), 31 had unintentional weight loss and 19 fulfilled malnutrition criteria defined by the ESPEN consensus. Nutrition‐related conditions were frequent: 94 patients had frailty, 44 sarcopenia, 58 overweight/obesity, and 59 nutrient deficiency. Sarcopenia reduced functional status at 3‐month follow‐up (median difference: −25.5; 95% confidence interval (CI) −46.4 – −4.3, P = 0.008). Institutionalization was related to unintentional weight loss in univariate analysis (odds ratio (OR) = 3.9; 95%CI 1.3 – 12.4, P = 0.018). Meeting the basic ESPEN definition of malnutrition was related to institutionalization in univariate (OR = 3.4; 95%CI 1.0 to 11.3, P = 0.042) but not multivariate analysis, and was not significantly associated with readmissions or mortality at 3‐month follow‐up.

Conclusions

Further research is needed on the potential value of the ESPEN consensus and guidelines for malnutrition to identify older patients at risk of worse functional status, institutionalization, readmissions, and mortality at 3‐month follow‐up postdischarge.
Meshfree modeling of a fluid‐particle two‐phase flow with an improved SPH method
Authors: Zhang Z. L. , Walayat K. , Chang J. Z. , Liu M. B.
Published: August 2018

Fluid‐particle two‐phase flows are very complex and quite challenging to numerically simulate due to the complex and constantly moving fluid‐particle interface. Recent developments in meshfree and particle methods provide alternatives in modeling fluid flows with moving boundaries. In this paper, a modified smoothed particle hydrodynamics (SPH) method is developed to simulate particle sedimentation (two‐dimensional) in Newtonian fluids. The modified SPH includes an enhanced particle approximation scheme, an effective solid boundary treatment algorithm, the artificial stress model, and a turbulence model. By decoupling a field variable and its derivatives in a finite particle method, a decoupled finite particle method is presented, which balances accuracy, efficiency, and stability in SPH simulations without the necessity of solving redundant and challenging corrective matrix equations. A coupled dynamic solid boundary treatment is developed to improve the accuracy near the fixed and moving solid boundaries. The artificial stress term is added into the SPH equations of motion to remove the possible tensile instability phenomenon. The large eddy simulation model is incorporated into the SPH to describe the turbulence effects at high Reynolds numbers. Four different particle sedimentation tests are conducted using the modified SPH along with the finite element fictitious boundary method. It is demonstrated that the improved SPH method can achieve much better results than the conventional SPH while showing a good comparison with the results from the finite element fictitious boundary method and from other sources.
Adaptive BDDC algorithms for the system arising from plane wave discretization of Helmholtz equations
Authors: Peng Jie , Wang Junxian , Shu Shi
Published: August 2018

Balancing domain decomposition by constraints algorithms with adaptive primal constraints are developed in a concise variational framework for the weighted plane wave least‐squares discretization of Helmholtz equations with high and various wave numbers. The unknowns to be solved in this preconditioned system are defined on elements rather than vertices or edges, which are different from the well‐known discretizations such as the classical finite element method. Through choosing suitable “interface” and appropriate primal constraints with complex coefficients and introducing some local techniques, we developed a two‐level adaptive balancing domain decomposition by constraints algorithm for the plane wave least‐squares discretization, and the condition number of the preconditioned system is proved to be bounded above by a user‐defined tolerance and a constant that is only dependent on the maximum number of interfaces per subdomain. A multilevel algorithm is also attempted to resolve the bottleneck in large‐scale coarse problem. Numerical results are carried out to confirm the theoretical results and illustrate the efficiency of the proposed algorithms.
Construction of the Pentacyclic Core and Formal Total Synthesis of (rac)‐Renieramycin T
Authors: Kimura Shinya , Saito Naoki
Published: August 2018

A formal total synthesis of the antitumor marine natural product (rac)‐renieramycin T, which possesses a characteristic ecteinascidin‐type A ring in the renieramycin–saframycin core skeleton, was elaborated. The key steps in the synthesis of (rac)‐renieramycin T are a modified Pictet–Spengler cyclization of dialkylated oxomalonate derivatives and decarboxylation via a monocarboxylic acid derivative followed by stereocontrolled protonation of the enol intermediate. A key intermediate in our previous synthesis of renieramycin T was used, and the formal synthesis was accomplished in 21 steps from a known piperazine‐2,5‐dione derivative.
The Effect of Stitching with Conductive and Nonconductive Materials on the Mode I Interlaminar Fracture Toughness of Carbon Fiber Composites
Authors: Abdelal Nisrin R. , Donaldson Steven L.
Published: August 2018

This study presents the effects of the stitching with seven threads, having a variety of mechanical properties from brittle to highly ductile behavior, on the delamination resistance/interlaminar fracture toughness of stitched carbon fiber‐epoxy laminated composites. Conductive Copper, Titanium, and Kevlar metallic, as well as non‐conductive Dyneema‐13 Kg, Dyneema‐T90, Kevlar‐10 Kg, and Kevlar‐13 Kg threads were tested for their mechanical properties. Next, laminates of unidirectional carbon fiber‐epoxy composites stitched with these fibers were fabricated using a vacuum assisted resin transfer molding process. Double cantilever beam tests were conducted on samples from the stitched and unstitched composites for comparison. Subsequent fractographic analysis using scanning electron microscope and optical microscope were conducted to reveal the relation between the stitch type and the energy release rate. Experimental results showed that during the crack initiation stage, composites stitched with Kevlar metallic exhibited an average 393% increase in Mode I critical energy release rate, GIC, the largest increase of the seven thread material types studied. At the fully developed crack propagation stage, composites stitched with Dyneema exhibited a 984% increase in GIC. However, composite stitched with copper and titanium exhibited 375% and 497% increase in GIC at the propagation stage, respectively. SEM and optical microscopic analysis revealed a strong relation between the inherent features of the thread materials and the delamination resistance. POLYM. COMPOS., 40:E1252–E1262, 2019. © 2018 Society of Plastics Engineers
Morphological, Thermal, and Mechanical Behavior of Polyamide11/Sepiolite Bio‐Nanocomposites Prepared by Melt Compounding and In Situ Polymerization
Authors: Herrero Manuel , Asensio María , Núñez Karina , Merino Juan Carlos , Pastor José María
Published: August 2018

The use of bio‐based plastics as polymeric matrices to produce technical composites has become an important topic in material science. In this sense, bio‐based polyamides represent an interesting alternative to their petroleum‐based counterparts because of their good thermal and mechanical properties, their low specific weight, and their ability to be used in complex parts by injection molding. In the present study, bio‐based polyamide 11/sepiolite nanocomposites were prepared using the two most feasible techniques from the industrial point of view: melt compounding and in situ polymerization. The effect of the preparation approach and the amount of nanoclay were evaluated to check their influence on thermal, morphological, and mechanical behavior of the final nanocomposites. Regardless of the preparation approach, all nanocomposites showed improvements in thermo‐mechanical properties with increasing contents of sepiolite. However, the nanocomposites obtained by in situ polymerization presented higher values of Young's modulus, tensile strength, and heat distortion temperature due to a greater dispersion of the nanoclay in the final composites. For in situ polymerization, the dispersion of sepiolite nanoparticles is carried out when polymer chains are growing and the viscosity of the system is low. POLYM. COMPOS., 40:E704–E713, 2019. © 2018 Society of Plastics Engineers
Mechanical, dynamic, and thermomechanical properties of coir/pineapple leaf fiber reinforced polylactic acid hybrid biocomposites
Authors: Siakeng Ramengmawii , Jawaid Mohammad , Ariffin Hidayah , Sapuan S. M.
Published: August 2018

Natural fiber‐based polymer composites have been widely studied to substitute synthetic materials. In this research, pineapple leaf fibers (PALF) and coir fibers (CF) were loaded into a polylactic acid (PLA) matrix to develop composite materials with improved mechanical and thermal properties, which could be potentially applied as biodegradable food packaging. Biocomposites with different fiber ratios were manufactured using an internal mixer plasticizer and a hot press machine. Mechanical and thermal analyses of the obtained composites were carried out and the results were compared with those of pure PLA. Scanning electron microscopy (SEM) was used to observe the microstructural failure of the composites. Mechanical tests indicated that all the composites had higher tensile and flexural modulus, compared to those of neat PLA. Also, strength values were increased upon addition of PALF, while impact tests showed enhanced strength results upon addition of CF. SEM findings confirmed the outcomes of the mechanical tests. DMA results confirmed that the storage and loss moduli of the CF/PALF/PLA hybrid composites increased with respect to those of the neat PLA, whereas the tan δ decreased. The coefficient of thermal expansion (CTE) of the PLA composites decreased with the addition of fiber reinforcements. Based on the results achieved in this investigation, the hybrid composite containing CF and PALF in a 1:1 ratio (C1P1) presented the optimum set of mechanical properties and improved thermal stability, which make it suitable for applications such as food packaging and structure components to help reduce the environmental loads. POLYM. COMPOS., 40:2000–2011, 2019. © 2018 Society of Plastics Engineers
Electrochemical sensor based on nanostructured ion imprinted polymer for the sensing and extraction of Cr(III) ions from industrial wastewater
Authors: Aravind Archana , Mathew Beena
Published: August 2018

In the present study we prepared a novel ion imprinted polymer as a sensitive electrochemical sensor for the determination of Cr(III) ion. The Cr(III) ion imprinted polymer was fabricated on a platinum electrode. Due to the presence of a nanolayer on the ion imprinted polymer with specific binding sites, the sensor reacted quickly to Cr(III) ion and can be used for selective extraction of Cr(III) ion. The Cr(III) ion imprinted polymer was prepared by using methacrylic acid as the functional monomer, N,N'‐methylene‐bis‐acrylamide as the crosslinking agent, potassium peroxodisulfate as initiator and Cr(III) ion as the template molecule. Non‐imprinted polymers were also prepared for comparative studies. The synthesized polymer was characterized using Fourier transform IR spectroscopy, TEM, Energy‐dispersive X‐ray spectroscopy and XRD. The limit of detection of the platinum–mutiwalled carbon nanotube ion imprinted polymer sensor was found to be 0.051 µmol L–1 using differential pulse voltammetry. Moreover, the proposed method was effectively used for the sensing and extraction of Cr(III) ion in real samples collected from the metal plating industry. © 2018 Society of Chemical Industry
High‐efficiency flexible III‐V photovoltaic solar cells based on single‐crystal‐like thin films directly grown on metallic tapes
Authors: Pouladi Sara , Rathi Monika , Khatiwada Devendra , Asadirad Mojtaba , Oh Seung Kyu , Dutta Pavel , Yao Yao , Gao Ying , Sun Sicong , Li Yongkuan , Shervin Shahab , Lee Keon‐Hwa , Selvamanickam Venkat , Ryou Jae‐Hyun
Published: August 2018

This study demonstrates the first flexible single‐junction III‐V photovoltaic solar cells (SCs) based on single‐crystal‐like gallium arsenide (GaAs) thin films on a low‐cost metal substrate by direct and continuous deposition, which can bypass expensive single crystal wafer fabrication. The two‐dimensional modeling of the GaAs SC is developed and used to study feasibility of single‐crystal‐like GaAs thin films for high performance SC devices. A promising SC device performance characteristic with an open‐circuit voltage of 560 mV and short circuit current of 19.4 mA/cm2, resulting in a conversion efficiency of ~7.6%, is demonstrated.
Approaches for synthesis of soluble poly(3,6‐dihydroxy‐2,7‐carbazole) with phenolic function
Authors: Aso Fumihiro , Kawashima Hidehisa , Kijima Masashi
Published: August 2018

Poly(N‐alkyl‐3,6‐dihydroxy‐2,7‐carbazole) which should be soluble and have phenolic function was synthesized through different two routes. The former method was a direct synthesis by polymerizing a 2,7‐dibromo‐3,6‐dihydroxycarbazole monomer using Ni(cod)2, which only gave a low molecular weight polymer. The latter method was an ether cleavage reaction of methoxy groups in a precursor polymer, poly(3,6‐dimethoxycarbazole), using BBr3, which gave successfully the objective polymer that has a number average molecular weight of 4300 g/mol comparable to the precursor polymer. They showed large spectral changes in photoabsorption and fluorescence on addition of base. They also showed redox behavior similar to a hydroquinone/benzoquinone couple investigated by cyclic voltammetry. These new functions could be derived from the phenolic hydroxy group in the carbazole unit. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2039–2044
Effects of alkyl side chain length of low bandgap naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole‐based copolymers on the optoelectronic properties of polymer solar cells
Authors: Tong Junfeng , An Lili , Li Jianfeng , Lv Jie , Guo Pengzhi , Li Liujun , Zhang Peng , Yang Chunyan , Xia Yangjun , Wang Chenglong
Published: August 2018

Two donor‐π‐acceptor (D‐π‐A) type naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole (NT)‐based conjugated copolymers (CPs), namely, PBDT‐TT‐DTNT‐HD and PBDT‐TT‐DTNT‐OD, containing different side chain length (2‐hexyldecyl, HD and 2‐octyldodecyl, OD) anchoring to thiophene π‐bridge between the two‐dimensional (2D) 5‐((2‐butyloctyl)thieno[3,2‐b]thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene (BDT‐TT) unit and NT moiety are developed and fully characterized. The resultant two copolymers exhibited broader absorption in wide range of 300–820 nm and obviously deepened EHOMO of approximately −5.50 eV. The effects of side chain length on film‐forming ability, absorption, energy levels, aggregation, dielectric constant (ɛr), mobility, morphology, and photovoltaic properties are further systematically investigated. It was found that the side chain length had little impact on solution‐processability, absorption, energy levels, and aggregation in CB solution of resultant CPs. However, tinily increasing side chain length promoted to form the more ordered structure of neat polymer film even if the corresponding ɛr decreased. As a result, the side‐chain‐extended PBDT‐TT‐DTNT‐OD:PC71BM‐based device achieved 32% increased FF than that of PBDT‐TT‐DTNT‐HD:PC71BM and thus the PCE was significantly raised from 3.99% to 5.21%, which were benefited from 2 times higher SCLC hole mobility, more favorable phase separation, and improved exciton dissociation. These findings could provide an important and valuable insight by side chain modulation for achieving efficient PSCs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2059–2071
Construction of excellent thermal latent system for the synthesis of networked epoxide polymers by sulfonium salts
Authors: Kawaoka Yoshiaki , Koge Katsushige , Sudo Atsushi , Endo Takeshi
Published: August 2018

An efficient thermally latent initiation system using dual sulfonium salts, consisting S‐benzylsulfonium salt 1 bearing
counter anion and S,S‐dimethylsulfonium salt 2 bearing CH3
counter anion, has been developed for the cationic polymerization of epoxides. Compared to the conventional system using 1 as a thermally latent initiator, the newly developed system allowed significant improvement of stability of epoxy formulations during storage at ambient temperature without sacrificing their curability at elevated temperatures. Such a remarkable performance is attributable to the nucleophilic attack of CH3
to cationic species formed unavoidably by the reaction of 1 with epoxide. Such entrapment of cationic species into the corresponding dormant led to the inhibition of undesirable chain growth of polymers during storage of epoxy formulations. In addition, the dormant can undergo dissociation at elevated temperature to give cationic species, which can readily initiate the polymerization of epoxide. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2096–2102
Study on Post‐Polymerization Modification of Ring‐Opening Metathesis Polymers Involving Pendant Thiolactone Units
Authors: Baysak Elif , Daglar Ozgun , Saim Gunay Ufuk , Hizal Gurkan , Tunca Umit , Durmaz Hakan
Published: August 2018

Two different oxanorbornene monomers were prepared and copolymerized with butyl‐functionalized oxanorbornene monomer through the ring‐opening metathesis polymerization. The resulting polymers were then subjected to the aminolysis reactions with propylamine (PA) in the presence of methyl acrylate (MA) to capture, in situ, the latent thiol. It was found that the polymer, in which the thiolactone unit is close to the polymer backbone, did not undergo an efficient aminolysis reaction even an excess amount of PA was utilized, while the other polymer, in which the thiolactone unit away from the polymer backbone, did efficiently undergo aminolysis reaction even PA was used in low amounts. Besides, a variety of primary amine compounds along with MA were reacted with the polymer, in which the thiolactone group away from the polymer backbone, to test their reactivity toward the aminolysis reactions. All modified polymers were characterized by using conventional instruments such as gel permeation chromatography, nuclear magnetic resonance, and differential scanning calorimetry. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2145–2153
A Partial Differential Equation Approach to Inhalation Physiologically Based Pharmacokinetic Modeling
Authors: Boger Elin , Wigström Oskar
Published: August 2018

The heterogeneous nature of the lungs and the range of processes affecting pulmonary drug disposition make prediction of inhaled drugs challenging. These predictions are critical, as the local exposure cannot be measured and current inhalation physiologically based pharmacokinetic (PBPK) models do not capture all necessary features. Utilizing partial differential equations, we present an inhalation PBPK model to describe the heterogeneity in both lung physiology and particle size. The model mechanistically describes important processes, such as deposition, mucociliary clearance, and dissolution. In addition, simplifications are introduced to reduce computational cost without loss of accuracy. Three case studies exemplify how the model can enhance our understanding of pulmonary drug disposition. Specific findings include that most small airways can be targeted by inhalation, and overdosing may eradicate the advantage of inhalation. The presented model can guide the design of inhaled molecules, formulations, as well as clinical trials, providing opportunities to explore regional targeting.
Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases
Authors: Abenavoli Ludovico , Izzo Angelo A. , Milić Natasa , Cicala Carla , Santini Antonello , Capasso Raffaele
Published: August 2018

Milk thistle (MT; Silybum marianum), a member of the Asteraceae family, is a therapeutic herb with a 2,000‐year history of use. MT fruits contain a mixture of flavonolignans collectively known as silymarin, being silybin (also named silibinin) the main component. This article reviews the chemistry of MT, the pharmacokinetics and bioavailability, the pharmacologically relevant actions for liver diseases (e.g., anti‐inflammatory, immunomodulating, antifibrotic, antioxidant, and liver‐regenerating properties) as well as the clinical potential in patients with alcoholic liver disease, nonalcoholic fatty liver disease, viral hepatitis, drug‐induced liver injury, and mushroom poisoning. Overall, literature data suggest that, despite encouraging preclinical data, further well‐designed randomized clinical trials are needed to fully substantiate the real value of MT preparations in liver diseases.
Effect of heat and singeing on stable hydrogen isotope ratios of bird feathers and implications for their use in determining geographic origin
Authors: Vander Zanden Hannah B. , Reid Abigail , Katzner Todd , Nelson David M.
Published: August 2018

Rationale

Stable hydrogen isotope (δ2H) ratios of animal tissues are useful for assessing movement and geographic origin of mobile organisms. However, it is uncertain whether heat and singeing affects featherδ2H values and thus subsequent geographic assignments. This is relevant for birds of conservation interest that are burned and killed at concentrating solar‐energy facilities that reflect sunlight to a receiving tower and generate a solar flux field.

Methods

We used a controlled experiment to test the effect of known heat loads (exposure to 200, 250 or 300°C for 1 min) on the morphology andδ2H values of feathers from two songbird species. Subsequently, we examined the effects of singeing onδ2H values of feathers from three other songbird species that were found dead in the field at a concentrating solar‐energy facility.

Results

Relative to control samples, heating caused visual morphological changes to feathers, including shriveling at 250°C and charring at 300°C. Theδ2H values significantly declined by a mean of 27.8‰ in experimental samples exposed to 300°C. There was no statistically detectable difference betweenδ2H values of the singed and unsinged portions of field‐collected feathers from the same bird.

Conclusions

Limited singeing that did not dramatically alter the feather morphology did not substantially affectδ2H values of feathers from these songbirds. However, higher temperatures induced charring and reducedδ2H values. Therefore, severely charred feathers should be avoided when selecting feathers forδ2H‐based assessment of geographic origin.
Rapid mass spectral fingerprinting of complex mixtures of decomposed lignin: Data‐processing methods for high‐resolution full‐scan mass spectra
Authors: Qi Yulin , Volmer Dietrich A.
Published: August 2018

Lignin is the second most abundant natural biopolymer and its wastes are significant sources for renewable chemicals as an alternative to conventional fossil fuels. Consequently, chemical characterization methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This short overview summarizes rapid data‐processing methods developed in our laboratory for application to full‐scan raw data from high‐resolution mass spectrometry experiments of decomposed lignin samples. The discussed graphical and statistical methods support the initial classification and elucidation of the main structural features of the lignin components without the need for time‐consuming tandem mass spectrometry analyses.
A novel gas chromatography–combustion–isotope ratio mass spectrometry derivatization method for nitrogen isotope analysis of nitrate in water
Authors: Li An , Chen Qiusheng , Pan Ligang , Dong Jieqiong , Jin Xinxin
Published: August 2018

Rationale

The stable nitrogen isotopic composition of nitrate (NO3−) can be an effective tool to identify NO3− sources and understand nitrogen cycling. However, the usefulness of this isotopic tool in environment research has been limited by complex analytical procedures for the nitrogen isotopic analysis of NO3−. We aimed to develop a novel method for the simple and rapid measurement of the δ15N value of NO3− in water.

Methods

Water NO3− was transformed into nitrobenzene for nitrogen isotopic analysis by gas chromatography–combustion–isotope ratio mass spectrometry (GC/C‐IRMS). The derivatization procedure was optimized to maximize the nitrobenzene yield. 1.5‐fold 98% sulfuric acid and 0.5‐fold benzene with respect to the water sample were used to derive nitrobenzene with only 1 min of vortex at room temperature. The nitrobenzene derivatization product (dissolved in benzene) was then separated by GC, followed by combustion to N2 for δ15N analysis by IRMS.

Results

The minimum amount of nitrogen required for accurate determination of the δ15N value was 8.6 ng at an m/z 28 intensity of 150 mV. The standard deviation of the GC/C‐IRMS method was ≤0.5‰ (three replicates) even at a low NO3− concentration of 9.58 mg L−1. The various standards and samples with different δ15N values exhibited good agreement with the assigned δ15N values obtained by using the proposed method.

Conclusions

Compared with previous methods, the newly developed method provided shorter analysis time and easy operation, and eliminated the need for the removal of chloride and nitrite. The GC/C‐IRMS derivatization method offers a fully operational tool for δ15N measurement of NO3− in water.
Untold stories of the Zika virus epidemic in Brazil
Authors: Avelino‐Silva Vivian I. , Kallas Esper G.
Published: August 2018

The Zika virus infection outbreak in Brazil in 2014 to 2015 resulted in the identification of previously unknown consequences of the disease, including the notorious microcephaly among many defects in fetuses born to women infected during pregnancy. A number of individuals were involved in this remarkable discovery, from the detection of viral circulation in the country to the studies on the causal link with congenital abnormalities and the provision of awareness and social support to families affected by the disease. In this article, we review the background to this experience, describing aspects of the epidemiology, medical research, and scientific response to the Zika virus outbreak in Brazil.
Flooding tolerance of Sagittaria latifolia and Sagittaria rigida under controlled laboratory conditions
Authors: Kenow Kevin P. , Gray Brian R. , Lyon James E.
Published: August 2018

Pool‐scale growing‐season water‐level reductions (drawdowns) have been implemented on the Upper Mississippi River in an effort to improve fish and wildlife habitat. Aquatic vegetation is a key habitat component, with perennial emergent species, such as Sagittaria latifolia and Sagittaria rigida, especially important. River managers have assumed the need for continuous drawdown during the growing season with limited reflooding and used this guidance in assessing the potential for an ecologically successful drawdown. However, information on the effects of growing‐season flooding episodes on survival and growth of Sagittaria is limited. To assess the flooding tolerance of S. latifolia and S. rigida, we evaluated multiple levels of timing, duration, and depth on survival and productivity of plants. Plants were produced from S. latifolia and S. rigida seeds and S. latifolia tubers; all were reared under moist‐soil or shallow‐flooded rearing conditions. Mortality of plants was low (2%) among plants from large tubers, low (7%) among seedlings (and largely associated with early flooding treatments), and modest (11%) among plants from small tubers (with no clear effects of inundation). Flooding treatments generally had a positive effect on biomass production from seedlings, particularly when treatments occurred early, were relatively shallow, and were short in duration. There were no clear effects of depth, duration, or timing components of flooding treatments on plant biomass arising from tubers. This experiment indicates that S. latifolia and S. rigida are relatively tolerant of flooding events during the growing season and may actually benefit from some level of inundation.
A comparison of bias‐corrected empirical covariance estimators with generalized estimating equations in small‐sample longitudinal study settings
Authors: Ford Whitney P. , Westgate Philip M.
Published: August 2018

Data arising from longitudinal studies are commonly analyzed with generalized estimating equations. Previous literature has shown that liberal inference may result from the use of the empirical sandwich covariance matrix estimator when the number of subjects is small. Therefore, two different approaches have been used to improve the validity of inference. First, many different small‐sample corrections to the empirical estimator have been offered in order to reduce bias in resulting standard error estimates. Second, critical values can be obtained from a t‐distribution or an F‐distribution with approximated degrees of freedom. Although limited studies on the comparison of these small‐sample corrections and degrees of freedom have been published, there is a need for a comprehensive study of currently existing methods in a wider range of scenarios. Therefore, in this manuscript, we conduct such a simulation study, finding two methods to attain nominal type I error rates more consistently than other methods in a variety of settings: First, a recently proposed method by Westgate and Burchett (2016, Statistics in Medicine 35, 3733‐3744) that specifies both a covariance estimator and degrees of freedom, and second, an average of two popular corrections developed by Mancl and DeRouen (2001, Biometrics 57, 126‐134) and Kauermann and Carroll (2001, Journal of the American Statistical Association 96, 1387‐1396) with degrees of freedom equaling the number of subjects minus the number of parameters in the marginal model.