Chromatographic performance of monodisperse macroporous particles produced by modified seeded polymerization. II. The effect of the diluent/seed‐latex ratio

Poly(styrene‐co‐divinylbenzene)‐based monodisperse macroporous particles were obtained by a modified seeded polymerization technique. The monodisperse polystyrene particles, obtained by dispersion polymerization in sufficiently large sizes and with suitable average molecular weights, were directly used as the seed latex in the production of macroporous particles. Therefore, the number of swelling and polymerization stages in the multistage production was reduced. In the first stage, the seed particles were swollen with a diluent, dibutyl phthalate (DBP), and then with a monomer phase including styrene, divinylbenzene, and, as an initiator, benzoyl peroxide. The monodisperse macroporous particles were obtained by the repolymerization of the monomer mixture in the seed particles. The particles, having different porosity characteristics, were synthesized through variations in the dibutyl phthalate/seed‐latex (DBP/SL) ratio. Selected macroporous particle samples were slurry‐packed into stainless steel high‐performance liquid chromatography columns (300 mm long × 7.8‐mm i.d.). The separation of the protein mixture by these columns in the reversed‐phase chromatography (RPC) mode was investigated. Liquid chromatograms with high resolutions were obtained under an acetonitrile/water gradient over a wide range of flow rates (i.e., 0.5–3 mL/min), especially for the particles produced with a monomer/seed‐latex (M/SL) ratio of 3.0 mL/g. In the RPC experiments, the particles produced with an M/SL ratio of 3.0 mL/g and DBP/SL ratios of 1.0 and 1.5 mL/g exhibited better chromatographic performance than the other samples. The maximum theoretical plate number was 3500 for the particles produced with the M/SL ratio of 3.0 mL/g and DBP/SL ratio of 1.5 mL/g with albumin as the analyte. The size exclusion chromatography (SEC) calibration curves and the back‐pressure/flow‐rate relationships of the produced columns were also determined. The particles obtained with an M/SL ratio of 3.0 mL/g and a DBP/SL ratio of 1.5 mL/g exhibited the best performance in SEC applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3685–3696, 2004     

Pseudotumor formation in tibia in Gaucher''s disease

Choriocarcinoma is an aggressive tumor with cyto- and syncytiotrophoblastic cells. It arises gestationally or nongestationally. Nongestational choriocarcinoma of the ovary can be pure or mixed with other germ cell tumors. Pure type is less frequent than mixed type and the diagnosis of nongestational choriocarcinoma of the ovary is very difficult in the reproductive period. A case of a 20-year-old woman with pure choriocarcinoma of the ovary is presented with a review of the literature and discussion of its origin.     

Automated design methodology for automobile side panel die using an effective optimization approach

In this study, two approaches are proposed to improve formability of an automobile side panel. In the first approach, the effect of using double binder on springback, wrinkling and thickness reduction is studied. In the second approach, the use of optimization method in further improving formability of the automobile panel is investigated. With the optimization method, the most appropriate values of forming process parameters are calculated for optimum formability characteristics. Positions of the upper die and draw-bead, draw-bead radius, forces applied on the upper die surface and double binder surfaces are considered as process parameters. In finding optimum values, finite element analysis, response surface methodology and genetic algorithm are integrated. To achieve efficient and effective integration, a computer program is written. From this study it is observed that double binder with an appropriate stamping force improves formability significantly. Application of optimization method also improves further formability characteristics of the automobile panel.     

Theory of Mind and Motion Perception in Schizophrenia.

This study investigated the relationship between theory of mind (ToM) deficits and visual perception in patients with schizophrenia (N=52; 17 remitted and unmedicated) compared with healthy controls (N=30). ToM was assessed with the Eyes Test, which asked participants to choose which of 4 words best described the mental state of a person whose eyes were depicted in a photograph. Visual perception was evaluated with form and motion coherence threshold measurements. Results revealed that patients with schizophrenia (both remitted and nonremitted) showed deficits on the Eyes Test and the motion coherence task. ToM dysfunctions were associated with higher motion coherence thresholds and more severe negative symptoms. This suggests that ToM deficits are related to motion perception dysfunctions, which indicates a possible role of motion-sensitive areas in the pathophysiology of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olive leaf extract as a crosslinking agent for the preparation of electrospun zein fibers

Incorporating active agents, reinforcing structure by crosslinking, thus changing release properties, can be listed as possible modifications in preparation methods of biopolymer fibers. This study introduces oleuropein, major component of olive leaf extract (OLE), as a natural functional crosslinker for electrospun zein fibers, owing to its antioxidant and antimicrobial properties. Incorporation of OLE causes morphological and structural changes indicated by a decrease in fiber diameter up to 27%, an increase in intensity of NH bending region due to interaction with –OH groups and observation of characteristic oleuropein bands. Extract addition also enhances thermal stability. Zein fibers without OLE is fully degraded at 600°C, whereas 10% of OLE loaded zein fibers is left undegraded. Fifty percent of initial phenolic content loaded into fibers is released which indicate the effect of OLE incorporation as accumulation of oleuropein. OLE‐incorporated fibers immersed in PBS are less fused than pure zein fibers, due to the crosslinking effect. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41338.     

Transactional Memory: An Overview

Writing applications that benefit from the massive computational power of future multicore chip multiprocessors will not be an easy task for mainstream programmers accustomed to sequential algorithms rather than parallel ones. This article presents a survey of transactional memory, a mechanism that promises to enable scalable performance while freeing programmers from some of the burden of modifying their parallel code.     

Macroporous hydrogel beads of high toughness and superfast responsivity

Macroporous hydrogel beads based on the monomers acrylamide and 2-acrylamido-2-methylpropane sulfonic acid sodium salt were prepared by dropwise addition of the monomer solution into the paraffin oil as the continuous phase at subzero temperatures. The beads prepared between ?15 and ?20 °C have irregular large pores of 1–10 μm in diameter, typical for macroporous networks created by the cryogelation technique, while nonporous hydrogels were obtained at room temperature. Swelling measurements show that the low temperature beads swell within seconds to attain their equilibrium states in water. The beads formed at subzero temperatures were very tough and can be compressed up to 94% strain without any crack development while those formed at room temperature were fragile and broke at a strain of about 40%. The results indicate that the tough hydrogel beads formed at subzero temperatures can be used in separation processes in which the separated compounds can easily be recovered by compression of the beads under a piston.     

Neural Network Based Control of the Acrylonitrile Polymerization Process

Acrylic fiber is commercially produced by free radical polymerization, initiated by a redox system. Industrial production of polyacrylonitrile is a variant of aqueous dispersion polymerization, which takes place in a homogenous phase under isothermal conditions with perfect mixing. The fact that the kinetics are a lot more complicated than those of ordinary polymerization systems makes it difficult to control the molecular weight. On the other hand, abundant data is being gathered in industrial polymerization systems, and this information makes the neural network based controllers a good candidate for managing such a difficult control problem. Multilayer neural networks have been applied successfully in the identification and control of dynamic systems. In this work, the neural network based control of continuous acrylonitrile (ACN) polymerization is studied, based on a previously developed new rigorous dynamic model for the polymerization of acrylonitrile. Two typical neural network controllers are investigated, i.e., model predictive control and NARMA‐L2 (Nonlinear Auto Regressive Moving Average) control. These controllers are representative of the variety of common ways in which multilayer networks are used in control systems. The results present a comparison of the two common neural network controllers, and indicate that the model predictive controller requires a larger computational time.     

How well do patients with schizophrenia track multiple moving targets?

It has been demonstrated that patients with schizophrenia perform poorly on tasks that require orienting, focusing, maintaining, and shifting attention. However, it is unknown how patients with schizophrenia can track multiple moving targets. To elucidate this issue, the authors investigated fast and slow multiple-object tracking in patients with schizophrenia (n = 30) and in matched healthy control participants (n = 30) and assessed their relationship with motion perception (velocity discrimination), sustained attention and context processing (Continuous Performance Test, 1-9 version; J. R. Finkelstein, T. D. Cannon, R. E. Gur, R. C. Gur, & P. Moberg, 1997), and object and spatial working memory. Results revealed that patients with schizophrenia displayed impaired performances on multiple-object tracking tasks. Linear regression analysis revealed a specific relationship among object tracking, velocity discrimination, and spatial working memory. In patients with schizophrenia, velocity discrimination and spatial working memory were the predictive factors of multiple-object tracking, whereas in healthy control participants, the single predictive factor was velocity discrimination. Probabilistic regression analysis revealed that only the Continuous Performance Test made significant contribution to discriminating between patients and control participants. These results suggest that multiple-object tracking is impaired in schizophrenia, and that it is specifically associated with motion perception and spatial working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A novel optimization algorithm for video placement and routing

In this paper, we propose a novel optimization algorithm for the solution of the video placement and routing problem based on Lagrangean relaxation,and decomposition. The main contribution can be stated as the use of integer programming models to obtain feasible solutions to the problem within the algorithm. Computational experimentation reveals that the use of such integer models help greatly in obtaining good quality solutions in a small amount of solution time.