1,699 research outputs found
Thiadizoloquinoxaline-Based Low-Bandgap Conjugated Polymers as Ambipolar Semiconductors for Organic Field Effect Transistors
Derivatizing Tribenzothiophene-Fused Hexa-peri-hexabenzocoronenes with Tunable Optoelectronic Properties
Hexa-peri-hexabenzocoronene with Different Acceptor Units for Tuning Optoelectronic Properties
Hexa-peri-hexabenzocoronene (HBC)-based donor–acceptor dyads were synthesized with three different acceptor units, through two pathways: 1) “pre-functionalization” of monobromo-substituted hexaphenylbenzene prior to the cyclodehydrogenation; and 2) “post-functionalization” of monobromo-substituted HBC after the cyclodehydrogenation. The HBC–acceptor dyads demonstrated varying degrees of intramolecular charge-transfer interactions, depending on the attached acceptor units, which allowed tuning of their photophysical and optoelectronic properties, including the energy gaps. The two synthetic pathways described here can be complementary and potentially be applied for the synthesis of nanographene–acceptor dyads with larger aromatic cores, including one-dimensionally extended graphene nanoribbons.</p
Synthesis, Photophysical Characterization, and Self-Assembly of Hexa-peri-hexabenzocoronene/Benzothiadiazole Donor-Acceptor Structure
Graduate Recital, Trombone
Throughout its history, the trombone has experienced a transformation as an instrument that plays a vital role in a wide variety of musical genres. My goal in preparing this recital was to give a survey of solo works for trombone that reflect this trend. These works include two concertos, one from the classical period and the other from the 20th century. Both works reflect the changes in attitude towards the trombone\u27s use as a solo instrument during these times. The second portion of the recital presents influences of American jazz and the avant garde through works that utilize improvisation and advanced playing techniques. The final part of the performance demonstrates the trombone\u27s capabilities in a chamber music setting utilizing a brass sextet. The varied program of this recital presents the possibilities of the wide range of musical expression possessed by the trombone
Control of the long-range self-organization of polycyclic aromatic hydrocarbons for device applications
Electronic devices based on organic semiconductors have gained increased attention in nanotechnology, especially applicable to the field of field-effect transistors and photovoltaic. A promising class of materials in this reseach field are polycyclic aromatic hydrocarbons (PAHs). Alkyl substitution of these graphenes results in the selforganization into one-dimensional columnar superstructures and provides solubility and
processibility. The nano-phase separation between the π-stacking aromatic cores and the disordered peripheral alkyl chains leads to the formation of thermotropic mesophases.
Hexa-peri-hexabenzocoronenes (HBC), as an example for a PAH, exhibits some of the highest values for the charge carrier mobility for mesogens, which makes them promising candidates for electronic devices. Prerequisites for efficient charge carrier transport between electrodes are a high purity of the material to reduce possible trapping sites for charge carriers and a pronounced and defect-free, long-range order. Appropriate processing techniques are required to induce a high degree of aligned structures in the discotic material over macroscopic dimensions. Highly-ordered supramolecular structures of different discotics, in particular, of HBC derivatives have been obtained by solution processing using the zone-casting technique, zone-melting or simple extrusion. Simplicity and fabrication of highly oriented columnar structures over long-range are the most essential advantages of these zone-processing methods. A close
relation between the molecular design, self-aggregation and the processing conditions has
been revealed. The long-range order achieved by the zone-casting proved to be suitable for field effect transistors (FET)
Detecting a Probiotic Product Within the Gut of Broiler Chickens
As of January 2017, the U.S. poultry industry banned the use of antibiotics and now relies on alternatives such as probiotics to help protect animal health. Although probiotic use is not a new concept in the poultry industry, identifying the best combination of bacterial strains to generate an effective probiotic formula requires further investigation. This study aimed to detect a probiotic product of four bacterial strains (Pedioccoccus acidilactici, Pediococcus pentosaceus, Lactobacillus plantarum, and Bacillus subtilis) in a feeding trial with broiler chickens. Birds given the probiotic were predicted to show an improved growth performance with the probiotics colonizing the gut. Ninety-six broiler chickens were equally divided into 3 treatment and 3 control pens. During the 25-day experiment, birds were fed a starter diet (days 0-11) and a grower diet (days 12-25). Experimental birds were administered the probiotic product via the drinking water at a concentration of 3.1×104 CFU/ml. Control birds had an equivalent amount of dextrose filler added to their water supply. Feces were collected hourly on day one and daily thereafter. On days 1, 22, and 25 of the experiment, 2 birds from each pen were euthanized for gut sampling. Lumen and mucosa samples were collected from the duodenum, jejunum, ileum, and ceca. Species-specific and strain specific PCR primers were employed for probiotic detection. Wild strains of P. acidilactici, P. pentosaceus, and L. plantarum were detected in the feeds, inhibiting detection of the probiotic strains when using species-specific PCR primers. Strain-specific primers were used to detect the probiotic Pedioccoccus acidilactici and Lactobacillus plantarum strains. B. subtilis was detected in feces within one hour of probiotic administration and was predominantly detected in experimental birds only. Both P. acidilactici and L. plantarum probiotic strains were initially detected in the feces of treated birds within two hours of probiotic administration and again ten days later. Both L. plantarum and B. subtilis were seen only in treated bird gut samples. L. plantarum was predominantly detected in the ceca near the end of the small intestine. P. pentosaceus was observed more often in treated gut samples and P. acidilactici was the least commonly detected probiotic strain. All administered bacteria were rarely seen in mucosa samples. Feed-endogenous P. acidilactici and L. plantarum strains became progressively more detectable in the mucosa along the gastrointestinal tract suggesting gut colonization, however, probiotic strains did not appear to colonize the mucosa of treated birds. Although probiotic strains were no longer detected after product removal, all probiotic strains were detected in feces and gut samples during probiotic administration, suggesting the bacteria can colonize the gut. Probiotic supplementation did not result in significant differences in body weight gain, feed intake, or feed conversion ratio. However, birds growing in a more stressful environment than the carefully controlled experimental set up used here may show probiotic-related effects. This study identified that the probiotic bacteria appeared to survive the gastrointestinal tract, exhibited a transit time of 1-2 hours, could possibly colonize chickens, and localized near the end of the chicken gut
A π-Extended Donor-Acceptor-Donor Triphenylene Twin linked via a Pyrazine-bridge
Beta-amino triphenylenes can be accessed via palladium catalyzed amination of the corresponding triflate using benzophe-none imine. Transformation of amine 6 to benzoyl amide 18 is also straightforward and its wide mesophase range demon-strates that the new linkage supports columnar liquid crystal formation. Amine 6 also undergoes clean aerobic oxidation to give a new twinned structure linked through an electron-poor pyrazine ring. The new discotic liquid crystal motif contains donor and acceptor fragments, and is more oval in shape rather than disk-like. It forms a wide range columnar mesophase. Absorption spectra are strong and broad; emission is also broad and occurs with a Stokes shift of ca. 0.7 eV, indicative of charge-transfer characte
Forcible Rape and the Right to Bail
This Comment examines the California Supreme Court\u27s holding in In re Underwood that bail may not be denied to protect the public from those charged with a non-capital offense. The author argues that despite the validity of the court\u27s proposition, the interests of society are under-protected with respect to the crime of forcible rape. The author suggests that a constitutional provision in needed, which denies the rights to bail to those accused of forcible rape when the proof is evident or the presumption great that the crime was committed. The author concludes that, while this proposed amendment would be constitutionally challenged, it would most likely survive constitutional scrutiny
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