Effect of Polycation Complexation on Methotrexate-Liposome Cytotoxicity

Methotrexate and methotrexate-DEAE dextran complex were microencapsulated in positively charged liposomes. Their cytotoxicity was determined and compared with the cytotoxicity of control systems against L1210 mouse leukemia eel Is at 37°C In acetate buffer of pH 7.40 ± 0.05. The control systems used were acetate buffer, blank liposome, DEAE-dextran liposome and methotrexate solution. The methotrexate and methotrexate-DEAE dextran liposomes were lyophilized and the Influence of lyophilization on their cytotoxicity was also examined. The methotrexate-DEAE dextran liposomes resulted in slightly higher mean growth ratios than the free methotrexate liposomes in non lyophilized as well as lyophilized systems. The ED⁵⁰ values for methotrexate and methotrexate-DEAE dextran liposomes were similar to that for the free methotrexate solution. This observation indicated that microencapsulation of methotrexate in liposomes either as a free drug or a complex has no effect on the cytotoxicity of the drug. In addition, lyophilization of liposome products does not seem to change their effectiveness.     

What determines the pattern of sharing of incubation and brooding in ring doves?

38 pairs of ring doves (Streptopelia risoria), nesting in the laboratory, showed stable patterns of sharing of incubation and brooding, with the male sitting on the eggs or young for a block of time toward the middle of the day. There was great variability from pair to pair in the amount and timing of sitting by each mate and in the frequency of nest exchanges. Despite this variability, the eggs were never left unincubated. It is shown that the particular sitting pattern of individual pairs cannot be accounted for by endogenous circadian differences for when each sex will incubate or by endogenous circadian differences in competing responses; they are probably due to the development of cooperative interactions between mates. The amount and pattern of sitting by each bird were stable over several breeding cycles but were altered when either partner was given a new mate. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shock: Aggregating Information While Preserving Privacy

An important problem facing large, distributed organizations is the efficient management and distribution of information, knowledge, and expertise. In this paper we present the design and implementation of a low-cost, extensible, flexible, and dynamic peer-to-peer (P2P) knowledge network that helps address this problem. This system, known as Shock, is designed to protect the privacy of user's personal information, such as email, web browsing habits, etc., while making that information available for knowledge management applications. It reduces participation costs for such applications as expert-finding, allows highly targeted messaging, and enables novel kinds of ad hoc conversation and anonymous messaging. The system is tightly integrated with users' email clients, taking advantage of email as habitat.     

A Feature-based Approach for Dense Segmentation and Estimation of Large Disparity Motion

We present a novel framework for motion segmentation that combines the concepts of layer-based methods and feature-based motion estimation. We estimate the initial correspondences by comparing vectors of filter outputs at interest points, from which we compute candidate scene relations via random sampling of minimal subsets of correspondences. We achieve a dense, piecewise smooth assignment of pixels to motion layers using a fast approximate graphcut algorithm based on a Markov random field formulation. We demonstrate our approach on image pairs containing large inter-frame motion and partial occlusion. The approach is efficient and it successfully segments scenes with inter-frame disparities previously beyond the scope of layer-based motion segmentation methods. We also present an extension that accounts for the case of non-planar motion, in which we use our planar motion segmentation results as an initialization for a regularized Thin Plate Spline fit. In addition, we present applications of our method to automatic object removal and to structure from motion.     

2-step optimization of the extraction and subsequent physical properties of channel catfish (Ictalurus punctatus) skin gelatin

ABSTRACT:  To optimize the extraction of gelatin from channel catfish ( Ictalurus punctatus ) skin, a 2-step response surface methodology involving a central composite design was adopted for the extraction process. After screening experiments, concentration of NaOH, alkaline pretreatment time, concentration of acetic acid, and extraction temperature were selected as the independent variables. In the 1st step of the optimization the dependent variables were protein yield (YP), gel strength (GS), and viscosity (V). Seven sets of optimized conditions were selected from the 1st step for the 2nd-step screen. Texture profile analysis and the 3 dependent variables from the 1st step were used as responses in the 2nd-step optimization. After the 2nd-step optimization, the most suitable conditions were 0.20 M NaOH pretreatment for 84 min, followed by a 0.115 M acetic acid extraction at 55 °C. The optimal values obtained from these conditions were YP = 19.2%, GS = 252 g, and V = 3.23 cP. The gelatin obtained also showed relatively good hardness, cohesiveness, springiness, and chewiness. The yield of protein and viscosity can be predicted by a quadratic and a linear model, respectively.     

A geometric method for automatic extraction of sulcal fundi

Sulcal fundi are 3-D curves that lie in the depths of the cerebral cortex and, in addition to their intrinsic value in brain research, are often used as landmarks for downstream computations in brain imaging. In this paper, we present a geometric algorithm that automatically extracts the sulcal fundi from magnetic resonance images and represents them as spline curves lying on the extracted triangular mesh representing the cortical surface. The input to our algorithm is a triangular mesh representation of an extracted cortical surface as computed by one of several available software packages for performing automated and semi-automated cortical surface extraction. Given this input we first compute a geometric depth measure for each triangle on the cortical surface mesh, and based on this information we extract sulcal regions by checking for connected regions exceeding a depth threshold. We then identify endpoints of each region and delineate the fundus by thinning the connected region while keeping the endpoints fixed. The curves, thus, defined are regularized using weighted splines on the surface mesh to yield high-quality representations of the sulcal fundi. We present the geometric framework and validate it with real data from human brains. Comparisons with expert-labeled sulcal fundi are part of this validation process.     

A 3‐in‐1 doping process for interdigitated back contact solar cells exploiting the understanding of co‐diffused dopant profiles by use of PECVD borosilicate glass in a phosphorus diffusion

Boron and phosphorus doping of crystalline silicon using a borosilicate glass (BSG) layer from plasma‐enhanced chemical vapor deposition (PECVD) and phosphorus oxychloride diffusion, respectively, is investigated. More specifically, the simultaneous and interacting diffusion of both elements through the BSG layer into the silicon substrate is characterized in depth. We show that an overlying BSG layer does not prevent the formation of a phosphorus emitter in silicon substrates during phosphorus diffusion. In fact, a BSG layer can even enhance the uptake of phosphorus into a silicon substrate compared with a bare substrate. From the understanding of the joint diffusion of boron and phosphorus through a BSG layer into a silicon substrate, a model is developed to illustrate the correlation of the concentration‐dependent diffusivities and the emerging diffusion profiles of boron and phosphorus. Here, the in‐diffusion of the dopants during diverse doping processes is reproduced by the use of known concentration dependences of the diffusivities in an integrated model. The simulated processes include a BSG drive‐in step in an inert and in a phosphorus‐containing atmosphere. Based on these findings, a PECVD BSG/capping layer structure is developed, which forms three different n⁺⁺−, n⁺− and p⁺−doped regions during one single high temperature process. Such engineered structure can be used to produce back contact solar cells. Copyright © 2016 John Wiley & Sons, Ltd.     

Quantitative characterization of polyacrylamide–shale interaction under various saline conditions

Interaction of polymer-containing injected fluids with shale is a widely studied phenomenon, but much is still unknown about the interaction of charged polyacrylamides such as anionic and cationic polyacrylamides with shale. The nature of interaction of charged polyacrylamides with shale is not well understood, especially from the perspective of assessing the potential for polyacrylamides to cause formation damage. Zeta potential and rheological measurements were made for Chattanooga and Pride Mountain shales suspended in polyacrylamide solutions with and without inorganic salts and tetramethyl ammonium chloride (TMAC). The change in zeta potential and viscosity with time was recorded. The magnitude of decrease in the absolute value of zeta potential with time is indicative of adsorption of polymer on the surface of shale and serves as a measure of the extent of polymer interaction with shale. The salts that were used in this study are potassium chloride (KCl), sodium chloride (NaCl). This study quantified the interaction of anionic and cationic polyacrylamide with different North American shales. From the experimental results, it was determined that the polyacrylamides can interact strongly with shale, particularly the cationic polyacrylamide. The objective of this study was to determine the extent of interaction of anionic and cationic polyacrylamide with each shale sample in the presence of additives such as salts.