bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anomalous water absorption by microelectronic encapsulants due to hygrothermal‐induced degradation
Authors: van Soestbergen Michiel , Mavinkurve Amar 
Published: July 2014

ABSTRACTEpoxy molding compounds are widely used as microelectronic encapsulants to protect the electronic circuitry from moisture. Since these compounds are hydrophilic they impose a reliability risk, which is assessed by lifetime tests. The interpretation of these tests is generally based on Fickian absorption. However, this work demonstrates that water absorption by microelectronic encapsulants shows anomalous behavior due to hygrothermal‐induced degradation of the material. Namely, experimental data show that the absorption by maiden samples is much slower than subsequent (de)sorption cycles, whereas the solubility depends on the highest water content that was reached in the history of the material. Moreover, at temperatures above glass transition the material might even physically decompose due to water exposure. Comparing these results with common theoretical models for anomalous water absorption shows that the experimental observed anomalies are most likely triggered by internal degradation of the encapsulant, which will impact the reliability assessment of epoxy encapsulated microelectronics. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41192.
Rheological, thermal, and mechanical properties of P (3HB‐co‐4HB) and P (3HB‐co‐4HB)/EVA blends
Authors: Guo Jing , Liu Mengzhu , Liu Yuanfa , Hu Chengnv , Xia Ying , Zhang Hong , Gong Yumei 
Published: July 2014

ABSTRACTPoly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐co‐4HB)] fiber and P(3HB‐co‐4HB)/EVA fiber were obtained by single screw extrusion machine. The rheology of P(3HB‐co‐4HB) and P(3HB‐co‐4HB)/EVA blends was characterized by capillary rheometer, and the chemical groups of the blends were characterized with Fourier transform infrared spectroscopy (FT‐IR). The crystallization behavior and thermal, mechanical and elastic properties of the fibers were measured by differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA) and single fiber strength tester, respectively. Besides, the moisture regain and drying shrinkage rates of the fibers were tested. These results showed that P(3HB‐co‐4HB)/EVA blends have better flowability, crystallinity, and thermal stability than P(3HB‐co‐4HB) fiber. The fracture strength of the P(3HB‐co‐4HB)/EVA fiber decreases with increasing the EVA content, but the elongation at break shows the contrary tendency. The rebound resilience ratio of P(3HB‐co‐4HB)/EVA fiber reaches 100%. Both moisture regain and drying shrinkage increase first and then decrease with increasing the EVA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41206.
Synergistic effect of THEIC‐Based charring agent on flame retardant properties of polylactide
Authors: Yuan Shanshan , Chen Wenyan , Liu Gousheng 
Published: July 2014

ABSTRACTA novel charring agent tris(2‐hydrooxyethyl) isocyanurate terephthalic acid ester, tetramer (TT4) was synthesized using tris(2‐hydrooxyethyl) isocyanurate and terephthalic acid as raw materials, and it was characterized by Fourier transformed infrared spectrometry and 1H‐NMR spectrum. It was combined with ammonium polyphosphate (APP) to form intumescent flame retardants for polylactide (PLA). The combustion properties and thermal stability of PLA/APP/TT4 composites were evaluated by UL‐94 burning tests, limiting oxygen index (LOI), and thermogravimetric analyses (TGA). It was found PLA with 30 wt % of APP/TT4 (5 : 1) achieved UL‐94 V‐0 rating and a 40.6 LOI value. Results from TGA demonstrated that APP/TT4 composites could retard the degradation of PLA above 410°C. The char residue at 500°C is higher than 24%, showing a good char forming ability. Moreover, the continuous and expansionary char layer observed from the SEM images proved good charring forming ability of TT4. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41218.
Stabilization And Tracking Of Underactuated Surface Vessels In Random Waves With Fin Based On Adaptive Hierarchical Sliding Mode Technique
Authors: Liu Cheng , Zou Zao‐jian , Hou Xian‐rui 
Published: July 2014

ABSTRACTTrajectory tracking and roll stabilization are both vital practices in ship motion control. Trajectory tracking is a kind of low‐frequency control, while roll stabilization by means of fins is a kind of high‐frequency control. However, they have been studied separately previously; most tracking control of underactuated surface vessels in the previous studies do not account for roll stabilization by means of fins. In reality, however, they are an integral system. In this paper, a simple control strategy is proposed to achieve trajectory tracking and fin roll stabilization simultaneously. Four degrees of freedom derived from a six degrees of freedom mathematical model of a surface vessel is considered, including surge, sway, roll and yaw. Surge force, roll moment and yaw moment are considered as control inputs, while position, yaw angle and roll angle are controlled. The number of control inputs is fewer than the outputs to be controlled. Therefore, we are dealing with an underactuated problem. An adaptive hierarchical sliding mode control technique is employed to deal with the underactuation. Stabilization of underactuated surface vessels is studied as a special case. Random waves are applied to test the robustness of the designed controllers. Lyapunov stability theory is used to show the stability of closed‐loop system. The simulation results verify the effectiveness of the proposed strategy.
Design of highly sensitive phosphorescence sensor for determination of procaterol hydrochloride based on inhibition of KClO3 oxidation fluorescein isothiocyanate
Authors: Liu Jia‐Ming , Huang Qitong , Liu Zhen‐bo , Zhang Li‐Hong , Zheng Zhi‐Yong , Lin Chang‐Qing 
Published: July 2014

AbstractProcaterol hydrochloride (Prh) can inhibit KClO3 oxidation of fluorescein isothiocyanate (FITC) to form a non‐phosphorescent compound, which causes room temperature phosphorescence (RTP) of FITC in the system to enhance sharply the linear relationship between ∆Ip and the Prh content. Thus, a rapid response and highly sensitive phosphorescence sensor for the determination of Prh has been developed based on the inhibiting effect of Prh on KClO3 oxidation of FITC. This simple, high sensitivity (detection limit (LD) calculated by 3Sb/k was 0.019 fg/spot, sample volume 0.40 µl, corresponding concentration 4.8 × 10–14 g ml–1) and selective sensor with a wide linear range (0.080–11.20 g/spot) has been applied to detect Prh in blood samples, and the results were consistent with those obtained by high‐performance liquid chromatography (HPLC). Simultaneously, the mechanism of the phosphorescence sensor for the detection of Prh was also investigated using infrared spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.
Undergraduates improve upon published crystal structure in class assignment
Authors: Horowitz Scott , Koldewey Philipp , Bardwell James C. 
Published: July 2014

AbstractRecently, 57 undergraduate students at the University of Michigan were assigned the task of solving a crystal structure, given only the electron density map of a 1.3 Å crystal structure from the electron density server, and the position of the N‐terminal amino acid. To test their knowledge of amino acid chemistry, the students were not given the protein sequence. With minimal direction from the instructor on how the students should complete the assignment, the students fared remarkably well in this task, with over half the class able to reconstruct the original sequence with over 77% sequence identity, and with structures whose median ranked in the 91st percentile of all structures of comparable resolution in terms of structure quality. Fourteen percent of the students' structures produced Molprobity steric clash validation scores even better than that of the original structure, suggesting that multiple students achieved an improvement in the overall structure quality compared to the published structure. Students were able to delineate limiting case chemical environments, such as charged interactions or complete solvent exposure, but were less able to distinguish finer details of hydrogen bonding or hydrophobicity. Our results prompt several questions: why were students able to perform so well in their structural validation scores? How were some students able to outperform the 88% sequence identity mark that would constitute a perfect score, given the level of degenerate density or surface residues with poor density? And how can the methodology used by the best students inform the practices of professional X‐ray crystallographers? © 2014 by The International Union of Biochemistry and Molecular Biology, 42(5):398–404, 2014.
Integrating an online compiler and a plagiarism detection tool into the Moodle distance education system for easy assessment of programming assignments
Authors: Kaya Mümine , Özel Selma Ayşe 
Published: July 2014

AbstractIn this study, an online compiler and a source code plagiarism detection tool have been included into the Moodle based distance education system of our Computer Engineering department. For this purpose Moodle system has been extended with the GCC compiler, and the Moss source code plagiarism detection tool. We observed that using the online compiler and the plagiarism detection tool reduces time and effort needed for the assessment of the programming assignments; prevents our students from plagiarism; and increases their success in their programming based Data Structures course. © 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:363–373, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21606
2′‐Bispyrene‐Modified 2′‐O‐Methyl RNA Probes as Useful Tools for the Detection of RNA: Synthesis, Fluorescent Properties, and Duplex Stability
Authors: Krasheninina Olga A. , Novopashina Darya S. , Lomzov Alexander A. , Venyaminova Alya G. 
Published: July 2014

AbstractThe synthesis and properties two series of new 2′‐O‐methyl RNA probes, each containing a single insertion of a 2′‐bispyrenylmethylphosphorodiamidate derivative of a nucleotide (U, C, A, and G), are described. As demonstrated by UV melting studies, the probes form stable complexes with model RNAs and DNAs. Significant increases (up to 21‐fold) in pyrene excimer fluorescence intensity were observed upon binding of most of the probes with complementary RNAs, but not with DNAs. The fluorescence spectra are independent of the nature of the modified nucleotides. The nucleotides on the 5′‐side of the modified nucleotide have no effect on the fluorescence spectra, whereas the natures of the two nucleotides on the 3′‐side are important: CC, CG, and UC dinucleotide units on the 3′‐side of the modified nucleotide provide the maximum increases in excimer fluorescence intensity. This study suggests that these 2′‐bispyrene‐labeled 2′‐O‐methyl RNA probes might be useful tools for detection of RNAs.
Therapeutic Applications of an Expanded Genetic Code
Authors: Sun Sophie B. , Schultz Peter G. , Kim Chan Hyuk 
Published: July 2014

AbstractTo date, over 100 noncanonical amino acids (ncAAs) have been genetically encoded in living cells in order to expand the functional repertoire of the canonical 20 amino acids. More recently, this technology has been expanded to the field of protein therapeutics, where traditional chemical methods typically result in heterogeneous mixtures of proteins. The site‐specific incorporation of ncAAs with orthogonal chemical groups allows unprecedented control over the site of conjugation and the stoichiometry, thus facilitating the rational optimization of the biological functions and/or pharmacokinetics of biologics. Herein, we discuss the recent contribution of ncAA technology in enhancing the pharmacological properties of current protein therapeutics as well as developing novel therapeutic modalities.
Bioorthogonal Fluorescent Labeling of Functional G‐Protein‐Coupled Receptors
Authors: Tian He , Naganathan Saranga , Kazmi Manija A. , Schwartz Thue W. , Sakmar Thomas P. , Huber Thomas 
Published: July 2014

AbstractNovel methods are required for site‐specific, quantitative fluorescent labeling of G‐protein‐coupled receptors (GPCRs) and other difficult‐to‐express membrane proteins. Ideally, fluorescent probes should perturb the native structure and function as little as possible. We evaluated bioorthogonal reactions to label genetically encoded p‐acetyl‐L‐phenylalanine (AcF) or p‐azido‐L‐phenylalanine (azF) residues in receptors heterologously expressed in mammalian cells. We found that keto‐selective reagents were not truly bioorthogonal, possibly owing to post‐translational protein oxidation reactions. In contrast, the strain‐promoted [3+2] azide–alkyne cycloaddition (SpAAC) with dibenzocyclooctyne (DIBO) reagents yielded stoichiometric conjugates with azF‐rhodopsin while undergoing negligible background reactions. As one application of this technique, we used Alexa488–rhodopsin to measure the kinetics of ligand uptake and release in membrane‐mimetic bicelles using a novel fluorescence‐quenching assay.
Asymmetric oxa‐Michael‐aza‐Henry Cascade Reaction of 2‐Hydroxyaryl‐Substituted α‐Amido Sulfones and Nitroolefins Mediated by Chiral Squaramides
Authors: Zheng Bo , Hou Wenduan , Peng Yungui 
Published: July 2014

AbstractA series of chiral squaramides were employed in the oxa‐Michael‐aza‐Henry cascade reaction of 2‐hydroxyaryl‐substituted α‐amido sulfones and nitroolefins. In the presence of 10 mol % of a squaramide catalyst and K2CO3 (aq) in CHCl3 at 0 °C, this reaction proceeded smoothly to afford chiral multisubstituted 4‐amino‐3‐nitrobenzopyrans, bearing a readily removable N‐Boc protecting group (Boc=tert‐butoxycarbonyl), in excellent yields (up to 98 %) and enantioselectivity [up to 98:2 enantiomeric ratio (er) and 93:7 diastereomeric ratio (dr)]. The 4‐amino‐3‐nitrobenzopyrans were converted into chiral 3,4‐diamino chromanes, which were further exploited as chiral ligands in the asymmetric transfer hydrogenation of acetophenone, providing 1‐phenylethanol in up to 84 % yield and 93.5:6.5 er.
Graphene Oxide and Its Functionalized Derivatives as Carbocatalysts in the Multicomponent Strecker Reaction of Ketones
Authors: Sengupta Ananya , Su Chenliang , Bao Chenlu , Nai Chang Tai , Loh Kian Ping 
Published: July 2014

AbstractFunctionalized graphene oxide derivatives are found to be efficient and reusable carbocatalysts for the one‐pot multicomponent Strecker reaction of aldehydes and ketones under neat and open‐air conditions.
Molecular Pom Poms from Self‐Assembling α,γ‐Cyclic Peptides
Authors: Panciera Michele , Amorín Manuel , Granja Juan R. 
Published: July 2014

AbstractThe hierarchical self‐assembly properties of a dimer‐forming cyclic peptide that bears a nicotinic acid moiety to form molecular pom‐pom‐like structures are described. This dimeric assembly self organizes into spherical structures that can encapsulate small organic molecules owing to its porosity and it can also facilitate metal deposition on its surface directed by the pyridine moiety.
Insight into the Interactions between Novel Coumarin Derivatives and Human A3 Adenosine Receptors
Authors: Matos Maria João , Vilar Santiago , Kachler Sonja , Fonseca André , Santana Lourdes , Uriarte Eugenio , Borges Fernanda , Tatonetti Nicholas P. , Klotz Karl‐Norbert 
Published: July 2014

AbstractA study focused on the discovery of new chemical entities based on the 3‐arylcoumarin scaffold was performed with the aim of finding new adenosine receptor (AR) ligands. Thirteen synthesized compounds were evaluated by radioligand binding (A1, A2A, and A3) and adenylyl cyclase activity (A2B) assays in order to study their affinity for the four human AR (hAR) subtypes. Seven of the studied compounds proved to be selective A3AR ligands, with 3‐(4′‐methylphenyl)‐8‐(2‐oxopropoxy)coumarin (12) being the most potent (Ki=634 nM). None of the compounds showed affinity for the A2B receptor, while four compounds were found to be nonselective AR ligands for the other three subtypes. Docking simulations were carried out to identify the hypothetical binding mode and to rationalize the interaction of these types of coumarin derivatives with the binding site of the three ARs to which binding was observed. The results allowed us to conclude that the 3‐arylcoumarin scaffold composes a novel and promising class of A3AR ligands. ADME properties were also calculated, with the results suggesting that these compounds are promising leads for the identification of new drug candidates.
Exorhodopsin and melanopsin systems in the pineal complex and brain at early developmental stages of Atlantic halibut (Hippoglossus hippoglossus)
Authors: Eilertsen Mariann , Drivenes Øyvind , Edvardsen Rolf B. , Bradley Clarrisa A. , Ebbesson Lars O.E. , Helvik Jon Vidar 
Published: July 2014

ABSTRACTThe complexity of the nonvisual photoreception systems in teleosts has just started to be appreciated, with colocalization of multiple photoreceptor types with unresolved functions. Here we describe an intricate expression pattern of melanopsins in early life stages of the marine flat fish Atlantic halibut (Hippoglossus hippoglossus), a period when the unpigmented brain is directly exposed to environmental photons. We show a refined and extensive expression of melanopsins in the halibut brain already at the time of hatching, long before the eyes are functional. We detect melanopsin in the habenula, suprachiasmatic nucleus, dorsal thalamus, and lateral tubular nucleus of first feeding larvae, suggesting conserved functions of the melanopsins in marine teleosts. The complex expression of melanopsins already at larval stages indicates the importance of nonvisual photoreception early in development. Most strikingly, we detect expression of both exorhodopsin and melanopsin in the pineal complex of halibut larvae. Double‐fluorescence labeling showed that two clusters of melanopsin‐positive cells are located lateral to the central rosette of exorhodopsin‐positive cells. The localization of different photopigments in the pineal complex suggests that two parallel photoreceptor systems may be active. Furthermore, the dispersed melanopsin‐positive cells in the spinal cord of halibut larvae at the time of hatching may be primary sensory cells or interneurons representing the first example of dispersed high‐order photoreceptor cells. The appearance of nonvisual opsins early in the development of halibut provides an alternative model for studying the evolution and functional significance of nonvisual opsins. J. Comp. Neurol. 522:4003–4022, 2014. © 2014 Wiley Periodicals, Inc.
Time‐Resolved, In Situ DRIFTS/EDE/MS Studies on Alumina‐Supported Rhodium Catalysts: Effects of Ceriation and Zirconiation on Rhodium–CO Interactions
Authors: Kroner Anna B. , Newton Mark A. , Tromp Moniek , Roscioni Otello M. , Russell Andrea E. , Dent Andrew J. , Prestipino Carmelo , Evans John 
Published: July 2014

AbstractThe effects of ceria and zirconia on the structure–function properties of supported rhodium catalysts (1.6 and 4 wt % Rh/γ‐Al2O3) during CO exposure are described. Ceria and zirconia are introduced through two preparation methods: 1) ceria is deposited on γ‐Al2O3 from [Ce(acac)3] and rhodium metal is subsequently added, and 2) through the controlled surface modification (CSM) technique, which involves the decomposition of [M(acac)x] (M=Ce, x=3; M=Zr, x=4) on Rh/γ‐Al2O3. The structure–function correlations of ceria and/or zirconia‐doped rhodium catalysts are investigated by diffuse reflectance infrared Fourier‐transform spectroscopy/energy‐dispersive extended X‐ray absorption spectroscopy/mass spectrometry (DRIFTS/EDE/MS) under time‐resolved, in situ conditions. CeOx and ZrO2 facilitate the protection of Rh particles against extensive oxidation in air and CO. Larger Rh core particles of ceriated and zirconiated Rh catalysts prepared by CSM are observed and compared with Rh/γ‐Al2O3 samples, whereas supported Rh particles are easily disrupted by CO forming mononuclear Rh geminal dicarbonyl species. DRIFTS results indicate that, through the interaction of CO with ceriated Rh particles, a significantly larger amount of linear CO species form; this suggests the predominance of a metallic Rh phase.
The Diverse Manifold of Electronic States Generated by a Single Carbon Defect in a Graphene Sheet: Multireference Calculations Using a Pyrene Defect Model
Authors: Machado Francisco B. C. , Aquino Adélia J. A. , Lischka Hans 
Published: July 2014

AbstractDetailed calculations have been performed on the electronic states occurring in a single vacancy defect model based on pyrene from which one of the central carbon atoms has been removed. Complete active space self‐consistent field and multireference configuration interaction with singles and doubles calculations have been performed using the 6‐31G and 6‐31G* basis sets. Two types of defect geometries have been defined: 1) The unrelaxed defect structure based on pyrene and 2) a relaxed structure. In total 12 electronic states have been computed for the unrelaxed structure at C2v symmetry, comprising four singlets, triplets and quintets each. The lowest six states are formed from singlet and triplet states and appear in a rather narrow gap of ∼0.6 eV. The lowest quintet state is found 1.43 eV above the 3B1 ground state. As predicted from Jahn–Teller distortions, a CC bond is formed between dangling carbon bonds in the 1, 3B1 states, leading to the formation of a five‐membered ring. The 1, 3A2 states show initial repulsive behavior along the bond formation coordinate until an avoided crossing is reached by which these states are furnished with CC bonding character so that finally also in these cases a CC bond is established. Linear interpolation curves between the initial unrelaxed defect structure and the final optimized structure are used to give an overview of the evolution of electronic states and the occurrence of avoided crossings. Out‐of‐plane structures are investigated with special emphasis on the carbon atom containing a dangling bond in the relaxed structure. Unpaired electron densities are used to characterize the electronic structure of the different states.
The Determinants of Green Product Innovation Performance
Authors: Chang Ching‐Hsun 
Published: July 2014

AbstractThis study utilizes structural equation modeling (SEM) to explore the positive effects of corporate environmental commitment and green human capital on green product innovation performance via the mediator: green adaptive ability. Green adaptive ability is the capability to comply with uncertain environmental regulations and environmentalism. This study tests the hypotheses in a sample of 136 of Taiwan's manufacturing companies. The findings in this study highlight the importance of corporate environmental commitment and green human capital that are determinants of green adaptive ability to develop green product innovation. The empirical results show corporate environmental commitment positively affects green product innovation performance directly and positively influences it indirectly via green adaptive ability. Green human capital, however, does not affect green product innovation performance directly. Green adaptive ability is a full mediator between green human capital and green product innovation performance but a partial mediator between corporate environmental commitment and green product innovation performance. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment