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.

Demystifying 3D ICs: the pros and cons of going vertical

Abstract: This article provides a practical introduction to the design trade-offs of the currently available 3D IC technology options. It begins with an overview of techniques, such as wire bonding, microbumps, through vias, and contactless interconnection, comparing them in terms of vertical density and practical limits to their use. We then present a high-level discussion of the pros and cons of 3D technologies, with an analysis relating the number of transistors on a chip to the vertical interconnect density using estimates based on Rent's rule. Next, we provide a more detailed design example of inductively coupled interconnects, with measured results of a system fabricated in a 0.35-/spl mu/m technology and an analysis of misalignment and crosstalk tolerances. Lastly, we present a case study of a fast Fourier transform (FFT) placed and routed in a 0.18-/spl mu/m through-via silicon-on-insulator (SOI) technology, comparing the 3D design to a traditional 2D approach in terms of wire length and critical-path delay.

Culture of pig embryos

Abstract: Pig embryos can be cultured using a number of different strategies including complex approaches like culture in vivo in a surrogate oviduct (rabbit, sheep, mouse), culture in mouse oviducts in organ culture, and co-culture of embryos with cells in addition to simple approaches like culture in defined media or salt solutions. Addition of serum to medium has been of particular importance where blastocyst development and hatching are required. Pig conceptuses (day 10-15), embryonic discs or cell lines derived from conceptuses can be cultured in complex media like Eagle's minimal essential medium or Dulbecco's modified Eagle's medium with serum, although embryonic discs can be cultured in the absence of serum. In contrast, early stage pig embryos (one-cell to blastocyst) are best cultured in simpler media such as those used for mouse embryos. The media that have been used are all relatively similar in composition. They contain salts and one or more energy sources such as glucose, lactate, or pyruvate with BSA as a macromolecular component. Early attempts to culture pig embryos were not very successful, but some embryos did develop to the blastocyst stage. More recent reports indicate a much higher rate of development with relatively little or no change in media composition. Some workers have reported improved development in medium lacking glucose, which is consistent with findings with laboratory animals such as hamsters. Glutamine can serve as the sole exogenous energy source in medium lacking glucose, lactate and pyruvate. Addition of taurine and hypotaurine to culture medium enhances development of pig embryos in vitro. We suggest, where possible, adoption of a standard medium that could be used by different laboratories and, perhaps, with different species. Use of one medium for different species would simplify experimental protocols, enhance studies of comparative embryonic physiology and metabolism, and expedite transfer of information obtained in different species.

Probing BSA binding to citrate-coated gold nanoparticles and surfaces.

Abstract: The interaction of bovine serum albumin (BSA) with gold colloids and surfaces was studied using ζ-potential and quartz crystal microbalance (QCM) measurements, respectively, to determine the surface charge and coverage. The combination of these two measurements suggests that BSA binding to gold nanoparticles and gold surfaces occurs by an electrostatic mechanism when citrate is present. The binding of BSA to bare gold is nearly two times greater than the binding of BSA to a citrate-coated gold surface, suggesting that protein spreading (denaturation) on the surface may occur followed by secondary protein binding. On the other hand, binding to citrate-coated gold surfaces can be fit to a Langmuir isotherm model to obtain a maximum surface coverage of (3.7 ± 0.2) × 1012 molecules/cm2 and a binding constant of 1.0 ± 0.3 μM-1. The ζ-potential measurements show that the stabilization of colloids by BSA has a significant contribution from a steric mechanism because the colloids are stable, even at their isoelec...

Three-dimensionally ordered array of air bubbles in a polymer film

Abstract: We report the formation of a three-dimensionally ordered array of air bubbles of monodisperse pore size in a polymer film through a templating mechanism based on thermocapillary convection. Dilute solutions of a simple, coil-like polymer in a volatile solvent are cast on a glass slide in the presence of moist air flowing across the surface. Evaporative cooling and the generation of an ordered array of breath figures leads to the formation of multilayers of hexagonally packed water droplets that are preserved in the final, solid polymer film as spherical air bubbles. The dimensions of these bubbles can be controlled simply by changing the velocity of the airflow across the surface. When these three-dimensionally ordered macroporous materials have pore dimensions comparable to the wavelength of visible light, they are of interest as photonic band gaps and optical stop-bands.