bluuebunny/crossref_metadata_2025_split huggingface dataset:
Switchable‐hydrophilicity solvent‐based microextraction combined with gas chromatography for the determination of nitroaromatic compounds in water samples
Authors: Rameshgar Jamileh , Hasheminasab Kobra Sadat , Adlnasab Laleh , Ahmar Hamid 
Published: June 2017

A simple, fast, sensitive, and low‐cost method was developed for the quantification of nitroaromatic compounds in water samples based on CO2‐assisted liquid‐phase microextraction using a switchable‐hydrophilicity solvent followed by gas chromatography detection. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible or immiscible upon the addition or removal of CO2 as a reagent. Experimental parameters affecting the extraction efficiency such as the volume of acceptor phase, the volume of donor phase, pH of donor phase, ionic strength, and extraction time were investigated. Under the optimal conditions, detection limits and preconcentration factors were obtained in the ranges of 0.9–1.8 μg/L and 132–138, respectively. Also, the extraction recoveries of water samples were above 88%. Finally, the developed method was successfully applied to the determination of nitroaromatic compounds in real water samples.
Application of capability indices and control charts in the analytical method control strategy
Authors: Oliva Alexis , Llabres Martinez Matías 
Published: June 2017

In this study, we assessed the usefulness of control charts in combination with the process capability indices, Cpm and Cpk, in the control strategy of an analytical method. The traditional X‐chart and moving range chart were used to monitor the analytical method over a 2‐year period. The results confirmed that the analytical method is in‐control and stable. Different criteria were used to establish the specifications limits (i.e. analyst requirements) for fixed method performance (i.e. method requirements). If the specification limits and control limits are equal in breadth, the method can be considered “capable” (Cpm = 1), but it does not satisfy the minimum method capability requirements proposed by Pearn and Shu (2003). Similar results were obtained using the Cpk index. The method capability was also assessed as a function of method performance for fixed analyst requirements. The results indicate that the method does not meet the requirements of the analytical target approach. A real‐example data of a SEC with light‐scattering detection method was used as a model whereas previously published data were used to illustrate the applicability of the proposed approach.
A simple, selective, and sensitive gas chromatography–mass spectrometry method for the analysis of five process‐related impurities in atenolol bulk drug and capsule formulations
Authors: Reddy Ambavaram Vijaya Bhaskar , Yusop Zulkifli , Jaafar Jafariah , Bin Aris Azmi , Abdul Majid Zaiton 
Published: June 2017

An extremely sensitive and simple gas chromatography with mass spectrometry method was developed and completely validated for the analysis of five process‐related impurities, viz., 4‐hydroxy‐l‐phenylglycine, 4‐hydroxyphenylacetonitrile, 4‐hydroxyphenylacetic acid, methyl‐4‐hydroxyphenylacetate, and 2‐[4‐{(2RS)‐2‐hydroxy‐3‐[(1‐methylethyl)amino]propoxy}phenyl]acetonitrile, in atenolol. The separation of impurities was accomplished on a BPX‐5 column with dimensions of 50 m × 0.25 mm i.d. and 0.25 μm film thickness. The method validation was performed following International Conference on Harmonisation guidelines in which the method was capable to quantitate 4‐hydroxy‐l‐phenylglycine, 4‐hydroxyphenylacetonitrile, and 4‐hydroxyphenylacetic acid at 0.3 ppm, and methyl‐4‐hydroxyphenylacetate and 2‐[4‐{(2RS)‐2‐hydroxy‐3‐[(1‐methylethyl)amino]propoxy}phenyl]acetonitrile at 0.35 ppm with respect to 10 mg/mL of atenolol. The method was linear over the concentration range of 0.3–10 ppm for 4‐hydroxy‐l‐phenylglycine, 4‐hydroxyphenylacetonitrile, and 4‐hydroxyphenylacetic acid, and 0.35–10 ppm for methyl‐4‐hydroxyphenylacetate and 2‐[4‐{(2RS)‐2‐hydroxy‐3‐[(1‐methylethyl)amino]propoxy}phenyl]acetonitrile. The correlation coefficient in each case was found ≥0.998. The repeatability and recovery values were acceptable, and found between 89.38% and 105.60% for all five impurities under optimized operating conditions. The method developed here is simple, selective, and sensitive with apparently better resolution than the reported methods. Hence, the method is a straightforward and good quality control tool for the quantitation of selected impurities at trace concentrations in atenolol.
Syringe‐to‐syringe dispersive liquid‐phase microextraction solidified floating organic drop combined with high‐performance liquid chromatography for the separation and quantification of ochratoxin A in food samples
Authors: Asadi Mohammad 
Published: June 2017

A new, simple, and rapid syringe‐to‐syringe dispersive liquid‐phase microextraction with solidified floating organic drop was used for the separation and preconcentration of ochratoxin A from grain and juice samples before its quantification using high‐performance liquid chromatography and fluorescence detection. Factors influencing the microextraction efficiency of ochratoxin A, such as sample solution pH, type and volume of organic extractant, salt concentration, number of injections, and volume of the sample, were studied and optimized. Under the optimum properties, the calibration graph showed linearity in the range of 65.0–700.0 ng/L (coefficient of determination = 0.9991). The limit of detection was 20.0 ng/L. The inter‐day and intra‐day relative standard deviations were in the range of 5.0–8.5%. This method was successfully applied for the quantification of ochratoxin A in grain and juice samples.
Clinical grading of Reinke's edema
Authors: Tan Melin , Bryson Paul C. , Pitts Casey , Woo Peak , Benninger Michael S. 
Published: June 2017

ObjectiveReinke's edema (RE) is a pathologically benign structural change of the vocal folds with a wide spectrum of clinical severity. We aim to propose and validate a clinical grading system based on size of the lesion to facilitate effective universal communication of disease severity.Study DesignRetrospective review.MethodsPatients diagnosed with RE exclusive of other glottic pathology between December 2010 and December 2014 were included. Sixty laryngoscopy photographs were extracted from recorded archived laryngeal videostroboscopy exams, blinded and graded by four laryngologists with experience diagnosing RE.ResultsA high degree of agreement among all four raters was demonstrated by high interclass correlation coefficients with a 95% confidence interval. Similarly, high intra‐rater reliability was seen across all raters. Forty‐nine (33%) lesions were grade 1. Thirty‐five lesions (29.17%) were grade 2; 18 (15%) lesions were grade 3; and nine (7.5%) lesions were grade 4. Contralateral vocal fold was not graded in cases of grade 4.ConclusionThis clinical grading for RE is a reliable tool for conveying severity of disease. High inter‐ and intra‐rater reliability strongly suggest that RE similarly can be graded by different raters, and that a single rater is expected to grade RE similarly at different times.Level of Evidence4. Laryngoscope, 127:2310–2313, 2017
NR4A1 is an endogenous inhibitor of vocal fold fibrosis
Authors: Hiwatashi Nao , Bing Renjie , Kraja Iv , Branski Ryan C. 
Published: June 2017

Objectives/HypothesisNR4A1 was recently identified as an endogenous inhibitor of transforming growth factor (TGF)‐β–induced fibrosis, and the role of this nuclear receptor has not been elucidated in tissue health or the response to injury in the vocal folds. Given the clinical implications of vocal fold fibrosis, we investigated NR4A1 expression during vocal fold wound healing in vivo and the regulatory roles of NR4A1 on vocal fold fibroblasts (VFFs) in vitro with the ultimate goal of developing targeted therapies for this challenging patient population.Study DesignIn vivo and in vitro.MethodsIn vivo, the temporal pattern of NR4A1 mRNA expression was quantified following rat vocal fold injury. In vitro, the role of NR4A1 on TGF‐β1–mediated transcription of genes underlying fibrosis as well as myofibroblast differentiation and collagen gel contraction was quantified in our human VFF line. Small interfering RNA was employed to alter NR4A1 expression to further elucidate this complex system.ResultsNr4a1 mRNA increased 1 day after injury and peaked at 7 days. Knockdown of NR4A1 resulted in upregulation of COL1A1 and TGF‐β1, with TGF‐β1 stimulation (both P < .001) in VFFs. NR4A1 knockdown also resulted in increased α‐smooth muscle actin–positive cells (P = .013) and contraction (P = .002) in response to TGF‐β1.ConclusionsNR4A1 has not been described in vocal fold health or disease. Upregulation of TGF‐β following vocal fold injury was concurrent with increased NR4A1 expression. These data provide a foundation for the development of therapeutic strategies given persistent TGF‐β signaling in vocal fold fibrosis.Level of EvidenceN/A Laryngoscope, 127:E317–E323, 2017
The application of wireless near infrared spectroscopy on detecting peripheral circulation in patients with diabetes foot ulcer when doing Buerger's exercise
Authors: Chen Min‐Ling , Lin Bor‐Shyh , Su Cheng‐Wei , Lin Yen‐Bin , Chen Mei‐Yen , Shen Jen‐Hsiang , Chang Chang‐Cheng 
Published: June 2017

Background and ObjectivesThe majority of patients with diabetes foot ulcer have peripheral arterial disease. The technique of near infrared spectroscopy (NIRS) used to monitor the dorsal foot blood circulation condition is by measuring the absorption differences between oxy‐hemoglobin and deoxy‐hemoglobin.Study Designs/Materials and MethodsPatients with diabetic foot ulcer (DFU) treated in our wound care center were divided into two sub‐groups based on the Duplex ultrasound or angiography. Patients with peripheral arterial disease (PAD) and non‐peripheral arterial disease were divided into group A1 and A2, respectively. We applied wireless NIRS on patients’ dorsal foot to assess the peripheral circulation by continuously detect the signal penetrating the tissue while patients were asked to do Buerger's exercise. The same procedure was also repeated on 15 healthy participants as control group B.ResultsFrom January to August 2015, 30 patients with DFU (Group A) were enrolled in the study, 9 patients in Group A1 and 21 patients in Group A2. Tissue concentration of oxygenated hemoglobin (HbO2) in each group varied in a similar trend among five stages of Buerger's exercise. HbO2 concentration increases at post‐exercise stages in all groups (P = 0.006 in Group A1, P = 0.223 in Group A2, P = 0.03 in Group B), however, there were significant difference in both pre‐ and post‐exercise stages (P = 0.001 and P = 0.01, respectively) between Group A and B. Moreover, significant differences (P = 0.0009) of HbO2 were also found between Group A1 and A2 in pre‐exercise status, but no significant difference (P = 0.294) was found in post‐exercise status. Similar results were also found in total hemoglobin (Hb) concentration analyses.ConclusionsBuerger's exercise could increase peripheral HbO2 and total Hb circulation in patients with diabetes foot ulcer. The NIRS could continuously and quantitatively monitor real‐time peripheral circulation in postural changes and is novel to rehabilitation program. A larger scale study to prove the accuracy of NIRS system in detecting peripheral circulation could be worthwhile. Lasers Surg. Med. 49:652–657, 2017. © 2017 Wiley Periodicals, Inc.
2,2,6,6‐Tetramethylpiperydinyl‐1‐oxyl (TEMPO) Functionalized Benzoxazines Prepared with a One‐Pot Synthesis for Reactive/Crosslinkable Initiators of Nitroxide Mediated Polymerization
Authors: Han Yi‐Jen , Liu Ying‐Ling 
Published: June 2017

In this work, the incorporation of a 2,2,6,6‐tetramethylpiperydinyl‐1‐oxyl (TEMPO) group to a benzoxazine ring is performed using a one‐pot synthesis for the preparation of TEMPO‐functionalized benzoxazine compounds and polymers as reactive and crosslinkable initiators for nitroxide‐mediated polymerization (NMP). The TEMPO‐functionalization reaction of benzoxazine, traced with 1H NMR, is conducted with sequential radical transfer and coupling reactions. Moreover, polystyrene‐grafted polybenzoxazine copolymers are prepared with the TEMPO‐benzoxazine initiator and NMP of styrene. The polymerization system exhibits the characteristics of controlled radical polymerization, including controlled molecular weights of products and ability for sequential polymerization. Moreover, based on the chemical reactivity and crosslinking ability of benzoxazine groups, the synthesis route developed in this work will widen the scope of the design and synthesis of functional and high‐performance polymers.
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Non‐contrast‐enhanced peripheral MR angiography using velocity‐selective excitation
Authors: Kim Dongchan , Seo Hyunseok , Cho Jaejin , Kwon Kinam , Han Yeji , Park HyunWook 
Published: June 2017

PurposeTo develop a new non‐contrast‐enhanced peripheral MR angiography that provides a high contrast angiogram without using electrocardiography triggering and saturation radiofrequency pulses.MethodsA velocity‐selective excitation technique is used in conjunction with the golden‐angle radial sampling scheme. The signal amplitude varies according to the velocity of the flow by the velocity‐selective excitation technique. Because the arterial blood velocity varies depending on the cardiac phase, the acquired data can be classified into systolic and diastolic phase based on the signal amplitude of the artery. Two images are then reconstructed from the systolic and diastolic phase data, respectively, and an image reflecting the differences between the two images is obtained to eliminate background and vein signals. The performance of the proposed method was compared with the quiescent‐interval single shot (QISS) in eight healthy subjects and an elderly subject.ResultsThe proposed method generated fewer residual venous and background signals than the QISS. Furthermore, the maximum intensity projection images, the relative contrast, and the apparent contrast‐to‐noise ratio results showed that the proposed method produced a better contrast than the QISS.ConclusionsThe proposed non‐contrast‐enhanced peripheral MR angiography technique can provide a high contrast angiogram without the use of electrocardiography triggering and saturation radiofrequency pulses. Magn Reson Med 79:779–788, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
A partitioned fully explicit Lagrangian finite element method for highly nonlinear fluid‐structure interaction problems
Authors: Meduri S. , Cremonesi M. , Perego U. , Bettinotti O. , Kurkchubasche A. , Oancea V. 
Published: June 2017

SummaryIn this work, a fully explicit partitioned method for the simulation of Fluid Structure Interaction (FSI) problems is presented. The fluid domain is modelled with an explicit Particle Finite Element Method (PFEM) based on the hypothesis of weak compressibility. The Lagrangian description of the fluid is particularly effective in the simulation of FSI problems with free surface flows and large structural displacements, since the fluid boundaries are automatically defined by the position of the mesh nodes. A distinctive feature of the proposed FSI strategy is that the solid domain is modelled using the explicit integration FEM in an off‐the‐shelf commercial software (Abaqus/Explicit). This allows to perform simulations with a complete and advanced description on the structural domain, including advanced structural material models and contact. The structure‐to‐fluid coupling algorithm is based on a technique derived from the Domain Decomposition Methods, namely, the Gravouil and Combescure algorithm. The method allows for arbitrarily large interface displacements using different time incrementation and nonconforming meshes in the different domains, which is an essential feature for the efficiency of an explicit solver involving different materials. The resulting fully explicit and fully lagrangian finite element approach is particularly appealing for the possibility of its efficient application in a large variety of highly non‐linear engineering problems.
Affine relaxations for the solutions of constrained parametric ordinary differential equations
Authors: Harwood Stuart M. , Barton Paul I. 
Published: June 2017

SummaryThis work presents a numerical method for evaluating affine relaxations of the solutions of parametric ordinary differential equations. This method is derived from a general theory for the construction of a polyhedral outer approximation of the reachable set (“polyhedral bounds”) of a constrained dynamic system subject to uncertain time‐varying inputs and initial conditions. This theory is an extension of differential inequality‐based comparison theorems. The new affine relaxation method is capable of incorporating information from simultaneously constructed interval bounds as well as other constraints on the states; not only does this improve the quality of the relaxations but it also yields numerical advantages that speed up the computation of the relaxations. Examples demonstrate that tight affine relaxations can be computed efficiently with this method.
Synthetic Approaches toward Monocyclic 3‐Amino‐β‐lactams
Authors: Deketelaere Sari , Van Nguyen Tuyen , Stevens Christian V. , D'hooghe Matthias 
Published: June 2017

AbstractDue to the emerging resistance against classical β‐lactam‐based antibiotics, a growing number of bacterial infections has become harder to treat. This alarming tendency necessitates continued research on novel antibacterial agents. Many classes of β‐lactam antibiotics are characterized by the presence of the 3‐aminoazetidin‐2‐one core, which resembles the natural substrate of the target penicillin‐binding proteins. In that respect, this Review summarizes the different synthetic pathways toward this key structure for the development of new antibacterial agents. The most extensively applied methods for 3‐amino‐β‐lactam ring formation are discussed, in addition to a few less common strategies. Moreover, approaches to introduce the 3‐amino substituent after ring formation are also covered.
Effects of cosolvents on helical substituted polyacetylene particles prepared through suspension polymerization
Authors: Zhang Yingjie , Lin Jiangfeng , Deng Jianping 
Published: June 2017

ABSTRACTAcetylenic monomers undergo aqueous suspension polymerization providing particles constructed by helical substituted polyacetylene. Different from suspension polymerization of vinyl monomers, a cosolvent is indispensable to dissolve Rh catalyst and solid acetylenic monomers. The cosolvent is found to play essential roles in monomers' polymerization and the particles' formation. To systemically explore the effects of cosolvents, three monomers, M1 (achiral, liquid), M2 (achiral, solid), and M3 (chiral, solid), and six cosolvents (divided into two groups by their miscibility with water) are used for performing suspension polymerization in aqueous media at 30 °C, with Rh+B– (C6H5)4 as catalyst and polyvinylpyrrolidone as stabilizer. FTIR spectra and gel permeation chromatography confirm the occurrence of polymerization. Raman spectra demonstrate the high cis contents of the polymer chains. Scanning electron microscope images show that the polymer particles obtained under optimal conditions are in spherical morphology. Circular dichroism and UV‐vis spectroscopy demonstrate the helical structures of the polymer chains forming the chiral particles. Dynamic light scattering characterization is carried out to characterize the nanoparticles. The type and amount of the cosolvent affect the polymerization remarkably. Cosolvents with higher polarity lead to smaller polymer particles, while lower polar cosolvents provide larger ones. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2670–2678
The effects of counter anions on the dynamic mechanical response in polymer networks crosslinked by metal–ligand coordination
Authors: Rao Ying‐Li , Feig Vivian , Gu Xiaodan , Nathan Wang Ging‐Ji , Bao Zhenan 
Published: June 2017

ABSTRACTMetal–ligand coordination has been proven to be an attractive strategy to tune a polymer network's dynamic mechanical properties, such as self‐healing ability. Nonetheless, the role of counter anions is often overlooked. To address this, a series of polydimethylsiloxane (PDMS) films crosslinked through lanthanide metal cations (Eu3+, Tb3+)–bipyridine interactions have been prepared and studied. Neutral 2,2'‐bipyridine ligands were embedded into the linear polydimethylsiloxane (PDMS) chain through polycondensation. With nitrate (
) as the coordinating anions, metal salts Eu(NO3)3 and Tb(NO3)3 were found to be ineffective crosslinkers. With noncoordinating anions, such as triflate (OTf‐: CF3
), metal salts Eu(OTf)3 and Tb(OTf)3 showed improved interaction strength with bipyridine ligands. Surprisingly, the addition of Eu(OTf)3 and Tb(OTf)3 salts also increased the d‐spacing distances of the phase‐segregated domains between metal–ligand complexes and the PDMS polymer backbone. For the Eu(OTf)3‐, Tb(OTf)3‐PDMS films, the much‐improved self‐healing abilities are attributed to the crosslinker dynamics and the enhanced chain mobility. This work underlines the importance of counter anions on the mechanical properties, and provides further guidance on the future design of self‐healing metal−ligand crosslinked polymers.) © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3110–3116
Coarse‐grained molecular dynamics simulation study on spherical and tube‐like vesicles formed by amphiphilic copolymers
Authors: Sun Xiao‐Li , Pei Shuai , Wang Jun‐Feng , Wang Pan , Liu Zhi‐Bin , Zhang Jun 
Published: June 2017

ABSTRACTMolecular‐level understanding of the vesicular structure and formation process is beneficial for potential vesicle applications, especially in drug delivery. In this article, coarse‐grained molecular dynamics simulation was used to study the self‐assembly behavior of amphiphilic poly(acrylic acid)‐b‐polystyrene copolymers in water at different concentrations and PS/PAA block ratios. It was found that various spherical and tube‐like vesicles formed at PS/PAA 3:3 and 4:2. For spherical vesicles, analysis of vesicular structure indicated that the cavity size was influenced by copolymer concentration and wall thickness by the block ratio. Tube‐like vesicle was formed via the fusion of two spherical vesicles, and a key factor for this morphology is polymer movements between inner and outer layer. This simulation study identifies the key factors governing vesicle formation and structure, and provides a guidance to design and prepare various vesicles for wide applications in drug delivery. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1220–1226