2,797 research outputs found

    Bibliography of reversed-phase partition chromatography

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    BIBLIOGRAPHY OF REVERSED-PHASE PARTITION CHROMATOGRAPH

    Toughening of BIS maleimide resins: Synthesis and characterization of maleimide terminated poly(arylene ether) oligomers and polymers

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    Amine functional poly(arylene ether) sulfones were previously reported. Herein, the chemistry was extended to amorphous poly(arylene ether) ketones because of their higher fracture toughness values, relative to the polysulfones. It was demonstrated that the amino functional oligomers undergo a self-crosslinking reaction at temperatures above about 220 C. This produces an insoluble, but ductile network that has excellent resistance. A ketamine structure hypothesis was proposed and verified using solid state magic angle NMR. In most cases, the water generated upon ketamine formation is too low to produce porosity and solid networks are obtained. The stability of the ketamine networks towards hydrolysis is excellent. The chemistry was further demonstrated to be able to crosslink preformed nonfunctional poly(arylene ether) ketones if a difunctional amine was utilized. This concept has the possibility of greatly improving the creep resistance of thermoplastics. Also, a new technique was developed for converting the amine functional oligomers cleanly into maleimide structures. This method involves reacting maleic anhydride with monomeric aminophenols in the presence of solvent mixtures

    Polyaryl ethers and related polysiloxane copolymer molecular coatings preparation and radiation degrdation

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    Poly(arylene ether sulfones) comprise a class of materials known as engineering thermoplastics which have a variety of important applications. These polymers are tough, rigid materials with good mechanical properties over a wide temperature range, and they are processed by conventional methods into products typically having excellent hydrolytic, thermal, oxidative and dimensional stability. Wholly aromatic random copolymers of hydroquinone and biphenol with 4.4 prime dichlorodiphenyl sulfone were synthesized via mechanical nucleophilic displacement. Their structures were characterized and mechanical behavior studied. These tough, ductile copolymers show excellent radiation resistance to electron beam treatment and retain much of the mechanical properties up to at least 700 Mrads under argon

    The Slothful Claw: Osteology and Taphonomy of \u3cem\u3eNothronychus mckinleyi\u3c/em\u3e and \u3cem\u3eN. graffami\u3c/em\u3e (Dinosauria: Theropoda) and Anatomical Considerations for Derived Therizinosaurids

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    Nothronychus was the first definitive therizinosaurian discovered in North America and currently represents the most specialized North American therizinosaurian genus. It is known from two species, No. mckinleyi from the Moreno Hill Formation (middle Turonian) in west-central New Mexico, and No. graffami from the Tropic Shale (early Turonian) in south-central Utah. Both species are represented by partial to nearly complete skeletons that have helped elucidate evolutionary trends in Therizinosauria. In spite of the biogeographical and evolutionary importance of these two taxa, neither has received a detailed description. Here, we present comprehensive descriptions of No. mckinleyi and No. graffami, the latter of which represents the most complete therizinosaurid skeleton known to date. We amend previous preliminary descriptions of No. mckinleyi and No. graffami based on these new data and modify previous character states based on an in-depth morphological analysis. Additionally, we review the depositional history of both specimens of Nothronychus and compare their taphonomic modes. We demonstrate that the species were not only separated geographically, but also temporally. Based on ammonoid biozones, the species appear to have been separated by at least 1.5 million years and up to 3 million years. We then discuss the impacts of diagenetic deformation on morphology and reevaluate potentially diagnostic characters in light of these new data. For example, the ulna of No. mckinleyi is curved whereas the ulna of No. graffami was considered straight, a character originally separating the two species. However, here we present the difference as much more likely related to diagenetic compression in No. graffami rather than as a true biologic difference. Finally, we include copies of three-dimensional surface scans of all major bones for both taxa for reference

    Wage Distribution Impacts of Higher Education Faculty Unionization

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    The literature on the effects of unions on the distribution of wages at the macroeconomic and inter-industry levels has given little attention to the effects at the firm level. At the same time, research on collective bargaining impacts in higher education has focused on the overall wage level rather than on the distribution of salaries. Using panel data on individual faculty members, we find faculty unionization to be associated with a significant flattening of the wage distribution across academic disciplines. This has implications for why faculty might choose to unionize, even in the absence of an overall wage premium

    Book Review Of Leap Of Faith By Danielle Steel

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    Leap of Faith is a novel by a famous novelist Danielle Steel. Leap of Faith debuted at the New York Times and is listed as the best-selling novel to fifty-two of Danielle Steel. This novel is about a girl from France, she is Marie-Ange Hawkins who lives in a magnificent castle name, Chateau de Marmouton. At the castle, she has childhood like everyone\u27s dream. She has the freedom, security and abundant affection of both parents and her brother. But when Marie-Ange Hawkins is eleven years old, a tragic accident that befell his parents take her happiness. She becomes an orphan and is sent to America to live with a cruel aunt of her father. Alone in a foreign land, Marie-Ange Hawkins becomes slave of agricultural land by her aunt, only her friendship with Billy and her dream to return to the castle of her childhood memories that make Marie-Ange endures. But the magic happens when Marie-Ange is 21 years old. She makes it back to the castle Chateau de Marmouton again and even get a chance to be the hostess which is the new owner of the castle, Comte Bernard de Beauchamp proposed her. But behind his proposal, Comte Bernard de Beauchamp keeps his hidden bad intentions to Marie-Ange Hawkins. In desperation and uncertainty areas around her, Marie-Ange has to find the faith and courage to take her last step to save her love ones and herself. Danielle Steel packed this book with very interesting by a simple writing style and storyline in the 1800s which is different from the usual. This book is quite interesting and deserves to be read as entertainment by teenagers and adults

    Male Field Cricket Songs Are Altered After Aggressive Interactions

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    To address the hypothesis that male acoustic sexual advertisement signals, in addition to chemical signals, might be indicators of aggressiveness, we examined the relationship between levels of aggression/dominance status and acoustic sexual advertisement signals in the field cricket Gryllus integer. Males were paired in aggression trials and recorded the night before and night after the trial. This allowed us to test whether aggression is inherently linked to song phenotypes, or whether aggressive interactions cause males to alter their songs. We found that dominant (winning) males signaled with higher energy, amplitude, and power the night after winning an aggressive encounter, but we could not detect any differences before the encounter. Time spent calling and the number of calling bouts were apparently unrelated to aggression, whereas winning males increased their bout lengths after winning, and losing males decreased their bout lengths after losing

    Bristles reduce the force required to ‘fling’ wings apart in the smallest insects

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    ABSTRACT The smallest flying insects commonly possess wings with long bristles. Little quantitative information is available on the morphology of these bristles, and their functional importance remains a mystery. In this study, we (1) collected morphological data on the bristles of 23 species of Mymaridae by analyzing high-resolution photographs and (2) used the immersed boundary method to determine via numerical simulation whether bristled wings reduced the force required to fling the wings apart while still maintaining lift. The effects of Reynolds number, angle of attack, bristle spacing and wing–wing interactions were investigated. In the morphological study, we found that as the body length of Mymaridae decreases, the diameter and gap between bristles decreases and the percentage of the wing area covered by bristles increases. In the numerical study, we found that a bristled wing experiences less force than a solid wing. The decrease in force with increasing gap to diameter ratio is greater at higher angles of attack than at lower angles of attack, suggesting that bristled wings may act more like solid wings at lower angles of attack than they do at higher angles of attack. In wing–wing interactions, bristled wings significantly decrease the drag required to fling two wings apart compared with solid wings, especially at lower Reynolds numbers. These results support the idea that bristles may offer an aerodynamic benefit during clap and fling in tiny insects

    Predicting sugar-sweetened behaviours with theory of planned behaviour constructs: Outcome and process results from the SIPsmartER behavioural intervention

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    Objective Guided by the theory of planned behaviour (TPB) and health literacy concepts, SIPsmartER is a six-month multicomponent intervention effective at improving SSB behaviours. Using SIPsmartER data, this study explores prediction of SSB behavioural intention (BI) and behaviour from TPB constructs using: (1) cross-sectional and prospective models and (2) 11 single-item assessments from interactive voice response (IVR) technology. Design Quasi-experimental design, including pre- and post-outcome data and repeated-measures process data of 155 intervention participants. Main Outcome Measures Validated multi-item TPB measures, single-item TPB measures, and self-reported SSB behaviours. Hypothesised relationships were investigated using correlation and multiple regression models. Results TPB constructs explained 32% of the variance cross sectionally and 20% prospectively in BI; and explained 13–20% of variance cross sectionally and 6% prospectively. Single-item scale models were significant, yet explained less variance. All IVR models predicting BI (average 21%, range 6–38%) and behaviour (average 30%, range 6–55%) were significant. Conclusion Findings are interpreted in the context of other cross-sectional, prospective and experimental TPB health and dietary studies. Findings advance experimental application of the TPB, including understanding constructs at outcome and process time points and applying theory in all intervention development, implementation and evaluation phases
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