North Carolina State University

About: North Carolina State University is a education organization based out in Raleigh, North Carolina, United States. It is known for research contribution in the topics: Population & Thin film. The organization has 44161 authors who have published 101744 publications receiving 3456774 citations. The organization is also known as: NCSU & North Carolina State University at Raleigh.

The fidelity of DNA synthesis by eukaryotic replicative and translesion synthesis polymerases.

Abstract: In their seminal publication describing the structure of the DNA double helix, Watson and Crick wrote what may be one of the greatest understatements in the scientific literature, namely that "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." Half a century later, we more fully appreciate what a huge challenge it is to replicate six billion nucleotides with the accuracy needed to stably maintain the human genome over many generations. This challenge is perhaps greater than was realized 50 years ago, because subsequent studies have revealed that the genome can be destabilized not only by environmental stresses that generate a large number and variety of potentially cytotoxic and mutagenic lesions in DNA but also by various sequence motifs of normal DNA that present challenges to replication. Towards a better understanding of the many determinants of genome stability, this chapter reviews the fidelity with which undamaged and damaged DNA is copied, with a focus on the eukaryotic B- and Y-family DNA polymerases, and considers how this fidelity is achieved.

Raman spectroscopy of diamond and doped diamond.

Abstract: The optimization of diamond films as valuable engineering materials for a wide variety of applications has required the development of robust methods for their characterization. Of the many methods used, Raman microscopy is perhaps the most valuable because it provides readily distinguishable signatures of each of the different forms of carbon (e.g. diamond, graphite, buckyballs). In addition it is non-destructive, requires little or no specimen preparation, is performed in air and can produce spatially resolved maps of the different forms of carbon within a specimen. This article begins by reviewing the strengths (and some of the pitfalls) of the Raman technique for the analysis of diamond and diamond films and surveys some of the latest developments (for example, surface-enhanced Raman and ultraviolet Raman spectroscopy) which hold the promise of providing a more profound understanding of the outstanding properties of these materials. The remainder of the article is devoted to the uses of Raman spectroscopy in diamond science and technology. Topics covered include using Raman spectroscopy to assess stress, crystalline perfection, phase purity, crystallite size, point defects and doping in diamond and diamond films.

Fluorine Substituents Reduce Charge Recombination and Drive Structure and Morphology Development in Polymer Solar Cells

Abstract: Three structurally identical polymers, except for the number of fluorine substitutions (0, 1, or 2) on the repeat unit (BnDT-DTBT), are investigated in detail, to further understand the impact of these fluorine atoms on open circuit voltage (Voc), short circuit current (Jsc), and fill factor (FF) of related solar cells. While the enhanced Voc can be ascribed to a lower HOMO level of the polymer by adding more fluorine substituents, the improvement in Jsc and FF are likely due to suppressed charge recombination. While the reduced bimolecular recombination with raising fluorine concentration is confirmed by variable light intensity studies, a plausibly suppressed geminate recombination is implied by the significantly increased change of dipole moment between the ground and excited states (Δμge) for these polymers as the number of fluorine substituents increases. Moreover, the 2F polymer (PBnDT-DTffBT) exhibits significantly more scattering in the in-plane lamellar stacking and out-of-plane π–π stacking dire...

Analysis of the composite structures in diamond thin films by Raman spectroscopy.

Abstract: Diamond and diamondlike thin films produced by various chemical-vapor-deposition processes have been examined using Raman spectroscopy. These films exhibit features in the Raman spectra, suggesting that they are composites of crystalline and amorphous diamond and graphitic structures. The components of this composite structure that contribute to the Raman scattering are discussed in terms of ${\mathrm{sp}}^{2}$- and ${\mathrm{sp}}^{3}$-bonded structures. The use of Raman spectroscopy as a technique for estimating the ${\mathrm{sp}}^{2}$-to-${\mathrm{sp}}^{3}$ bonding ratio is considered. Powder composites of BN-diamond and graphite-diamond have been studied as a means of modeling the films, and a simple theoretical model of the Raman scattering from these samples is proposed. From these results it is shown that it is necessary to make assumptions about the domain size of the graphitic ${\mathrm{sp}}^{2}$ regions. It is found that the Raman scattering associated with ${\mathrm{sp}}^{2}$ bonding in the films is much stronger than that from single-crystalline or microcrystalline graphite structures. Shifts of the vibrational modes are also observed. The optical and vibrational properties of the ${\mathrm{sp}}^{2}$ component in the films implies a different atomic microstructure. A model of the ${\mathrm{sp}}^{2}$-bonding configurations in the films is proposed which may account for the observed features in the Raman spectra.

Multilevel Interactions between Ethylene and Auxin in Arabidopsis Roots

Abstract: Hormones play a central role in the coordination of internal developmental processes with environmental signals. Herein, a combination of physiological, genetic, cellular, and whole-genome expression profiling approaches has been employed to investigate the mechanisms of interaction between two key plant hormones: ethylene and auxin. Quantification of the morphological effects of ethylene and auxin in a variety of mutant backgrounds indicates that auxin biosynthesis, transport, signaling, and response are required for the ethylene-induced growth inhibition in roots but not in hypocotyls of dark-grown seedlings. Analysis of the activation of early auxin and ethylene responses at the cellular level, as well as of global changes in gene expression in the wild type versus auxin and ethylene mutants, suggests a simple mechanistic model for the interaction between these two hormones in roots, according to which ethylene and auxin can reciprocally regulate each other's biosyntheses, influence each other's response pathways, and/or act independently on the same target genes. This model not only implies existence of several levels of interaction but also provides a likely explanation for the strong ethylene response defects observed in auxin mutants.