Optimal mode selection and synchronization for robust videocommunications over error-prone networks

We describe an effective method for increasing error resilience of video transmission over bit error prone networks. Rate-distortion optimized mode selection and synchronization marker insertion algorithms are introduced. The resulting video communication system takes into account the channel condition and the error concealment method used by the decoder, to optimize video coding mode selection and placement of synchronization markers in the compressed bit stream. The effects of mismatch between the parameters used by the encoder and the parameters associated with the actual channel condition and the decoder error concealment method are evaluated. Results for the binary symmetric channel and wideband code division multiple access mobile network models are presented in order to illustrate the advantages of the proposed method     

Absence of external E-field effects on transformations in steels

Large hardness increases were recently reported for an ASTM A723 steel and a tool steel when a 1 kVcm^–1 external electric field was applied during the post-austenitization quench. The increased hardness was attributed to a field-induced order-of-magnitude decrease in the austenite decomposition rate during the quench. The results of an extensive study of austenite decomposition kinetics in the same A723 steel and a similar tool steel in the presence and absence of electric fields of magnitudes up to 3 kVcm^–1 during post-austenitization cooling are reported here. Differential thermal analysis and thermomagnetic analysis were employed to directly monitor the austenite decomposition processes in both steels. Supplementary hardness measurements in the tool steel are also reported. No effects of external electric fields on austenite transformations were detected.     

Efficient phosphate binding using a combination of gluconolactate and carbonate calcium salts

Although renal-failure-related hyperphosphataemia can be corrected by various phosphate binders, there remains a need for safer and more efficient formulations to precipitate phosphate. This work describes both a theoretical approach and a phosphate precipitation test in order to design efficient binding calcium salts formulations. The results show that the combination of a soluble calcium salt (the gluconolactate) and a proton-consuming calcium salt (the carbonate) can precipitate phosphate effectively. Furthermore, the theoretical computations correlate well with the ability of the salt to bind phosphate in vitro.     

Processing of interfacial tension data in solvent extraction studies. Interfacial properties of various acidic organophosphorus extractants

Basically, the interfacial tension data can be plotted as a function of logarithm C where C denotes the concentration of any form of the surface active species considered. The various relationships y vs In C are discussed here from a mathematical point of view and it is shown that ambiguities may arise from the use of the interfacial tension curves versus the total extractant concentration for the interfacial tension data interpretation. The method recommended in this work is based on the computation of the whole surface excess curves (Γ vs concentration of individual species). This is achieved by matching various adsorption equations (e.g. Szyszkowski or Temkin relationships) or empirical equations to the interfacial tension data (y vs C). The term dy/dln C can then be analytically calculated and introduced into the Gibbs equation [Γ = ?(1/RT)dy/dln C] to derive mathematical expressions for the surface excess curves. To exemplify our approach, interfacial data are interpreted for dibutylphosphoric acid (HDBP), di(2-ethylhexyl)phosphoric acid (HDEHP), di(hexoxyethyl)phosphoric acid (HDHOEP), 2-ethylhexyl-2-ethylhexylphosphonic acid (HEH[EHP]) and di(2-ethylhexyl)phosphinic acid (H[DEHP]) at various liquid-liquid interfaces.     

Scattering from the perfectly conducting cube

The scattering cross sections in the E-plane, H-plane, and 45°-plane of the perfectly conducting cube illuminated broadside by an incident plane wave are computed using both a uniform high-frequency diffraction solution and magnetic-field integral equations. The computed cross sections are compared with measured cross sections for cube perimeters of 3, 6, 12, and 20 wavelengths. The total scattering cross section versus the perimeter of the cube is also computed and compared to that of the sphere     

Relationship of tumor angiogenesis and nuclear p53 accumulation in invasive bladder cancer

The purpose of this investigation was to evaluate the relationship between tumor angiogenesis and nuclear p53 accumulation in invasive bladder cancer. We studied 161 patients with invasive transitional cell carcinoma of the bladder who had previously undergone radical cystectomy. Analysis was performed to determine the presence of p53 nuclear accumulation and extent of tumor-associated angiogenesis. p53 status identified a group of patients at high risk for tumor progression (p53-altered tumors), and microvessel density determinations added additional prognostic information by identifying a subset of aggressive tumors within the wild-type p53 subgroup. At 5 years, patients with tumors exhibiting no evidence of p53 alterations and low microvessel counts demonstrated 3% recurrence and 88% survival, compared to 43% recurrence and 59% overall survival for patients with intermediate vessel counts and 61% recurrence and 43% overall survival for patients with the highest vessel counts (P < 0.001 and P = 0.003, respectively). Angiogenesis also provides additional prognostic information to patients with tumors that demonstrate p53 alterations. An association between angiogenesis and p53 status did exist (P = 0. 05); however, 27% of the tumors that showed no evidence of p53 alterations exhibited high microvessel counts, and 26% of tumors with evidence of p53 alterations had low microvessel counts. Tumor-associated angiogenesis adds additional useful prognostic information to that which is obtained from p53 status in patients with invasive transitional cell carcinoma of the bladder. Although an association between p53 status and the degree of angiogenesis was identified, other factors appear to play a role in the regulation of tumor-induced neovasularization.     

Two dimensional soft material: new faces of graphene oxide

Graphite oxide sheets, now called graphene oxide (GO), can be made from chemical exfoliation of graphite by reactions that have been known for 150 years. Because GO is a promising solution-processable precursor for the bulk production of graphene, interest in this old material has resurged. The reactions to produce GO add oxygenated functional groups to the graphene sheets on their basal plane and edges, and this derivatization breaks the π-conjugated network, resulting in electrically insulating but highly water-dispersible sheets. Apart from making graphene, GO itself has many intriguing properties. Like graphene, GO is a two-dimensional (2D) sheet with feature sizes at two abruptly different length scales. The apparent thickness of the functionalized carbon sheet is approximately 1 nm, but the lateral dimensions can range from a few nanometers to hundreds of micrometers. Therefore, researchers can think of GO as either a single molecule or a particle, depending on which length scale is of greater interest. At the same time, GO can be viewed as an unconventional soft material, such as a 2D polymer, highly anisotropic colloid, membrane, liquid crystal, or amphiphile. In this Account, we highlight the soft material characteristics of GO. GO consists of nanographitic patches surrounded by largely disordered, oxygenated domains. Such structural characteristics effectively make GO a 2D amphiphile with a hydrophilic periphery and largely hydrophobic center. This insight has led to better understanding of the solution properties of GO for making thin films and new applications of GO as a surfactant. Changes in pH and sheet size can tune the amphiphilicity of GO, leading to intriguing interfacial activities. In addition, new all-carbon composites made of only graphitic nanostructures using GO as a dispersing agent have potential applications in photovoltaics and energy storage. On the other hand, GO can function as a 2D random diblock copolymer, one block graphitic and the other heavily hydroxylated. Therefore, GO can guide material assembly through π-π stacking and hydrogen bonding. Additionally, the selective etching of the more reactive sp(3) blocks produces a porous GO network, which greatly enhances interactions with gas molecules in chemical sensors. With their high aspect ratio, GO colloids can readily align to form liquid crystalline phases at high concentration. As single-atomic, water-dispersible, soft carbon sheets that can be easily converted to a conductive form, this 2D material should continue to inspire many curiosity-driven discoveries and applications at the interfaces of chemistry, materials science, and other disciplines.