Polymorphism of POS. II. kinetics of melt crystallization

Melt crystallization of four polymorphs of POS, α,δ, pseudo-β′ andβ, was examined with pure samples (>99.9%). Induction time, τ, for newly occurring crystals was measured with a polarizing microscope equipped with a temperature-controlled growth cell. Rate of crystallization, 1/τ, was obtained for each polymorph, whose identification was done with x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Two modes of crystallization, melt cooling and melt mediation, were applied. From these experiments, the following conclusions were obtained: (i) The rate of melt-mediated crystallization was always higher than of simple melt cooling; (ii) the pseudo-β′ form was crystallized in a wider range of temperature than the less stable δ form; (iii) the occurrence behavior of the polymorphs differed between simple melt cooling and melt mediation; (iv) the δ form was crystallized only by simple melt cooling in a narrow range of temperature, 25.5°C∼28.3°C. This means that there is a possibility that δ may result from racemic compounds that are crystallized in a specific manner. The experimental results are discussed in comparison to 1,3-dipalmitoyl2-oleoylglycerol (POP), 1,3-distearoyl-2-oleoylglycerol (SOS) and cocoa butter.     

Current concepts on the role of oxytocin in milk ejection

Timing of oxytocin release may influence milk ejection. Oxytocin is higher in cows after manual premilking stimulation than in cows receiving no stimulation. Premilking stimulation offers no advantages to milk production in short trials but results in shorter times of machine on and higher average rate of milk flow. Enhanced mechanical stimulation does not seem as effective as manual stimulation in short trials. Oxytocin release is multiphasic, and contents in blood decline during milking. Maximal concentrations during milking decrease across lactation. Nonlactating cows also release oxytocin upon udder stimulation and conditioning. Virgin heifers do not respond in the same way to udder stimulation as lactating cows, thus suggesting that sensitivity of the milk ejection reflex depends upon the physiological state of the animal. Cows probably release about one-third of their stores of oxytocin at milking, and it appears that little hormone is necessary for effect at the udder. Basal concentrations of oxytocin decrease from early to midlactation and increase from mid to late lactation and from late lactation to involution. Half-lives, metabolic clearance rates, and entry rates for oxytocin were measured in cattle in various physiological states. Data from these measurements are discussed.     

Confectionery fats from palm oil

The influence of diglycerides (DG’s) and trisaturated glycerides (P-P-P) on tempering and the hardness of confectionery products are described. Palm oil and its processed products in confectionery fats have been reported (1,2). Palm oil contains a symmetric triglyceride (P-O-P) as a main component which has polymorphic changes similar to those of cocoa butter, so a mixture of these is able to use a tempering process similar to that used for cocoa butter. Details for fat crystals and polymorphism have been reported (3,4). Okada (5) used a mixture of tristearin and tripalmitin and studied the behavior of polymorphism using X-ray diffraction. The effects of DG’s on polymorphic change in palm oil also have been reported (6,7), and Okiy (8) suggested that DG’s have an inferior effect on the quality of palm oil when used in the solidified phase. However, there have not been many papers regarding how the above influence works in the production process or how it affects confectionery products. Palm oil contains about 10% trisaturated glycerides together with a few percent of mono- and diglycerides as minor components, which have been produced during the maturation of palm fruits and processing of fats. It is very difficult to eliminate these completely during the refining process. This paper reports a study of the influence of these minor components on tempering and hardness of products by using a simulated tempering machine. We have found that DG’s lower the temperature of tempering and soften the hardness of products and that P-P-P increased the viscosity of products during tempering process but increased the hardness of products very little.     

Electrospun nano‐scaled glass fiber reinforcement of bis‐GMA/TEGDMA dental composites

The objective of this study was to investigate the electrospun nano‐scaled glass fiber reinforcement of 2,2′‐bis[4‐(methacryloxypropoxy)‐phenyl]‐propane/triethylene glycol dimethacrylate (Bis‐GMA/TEGDMA) dental composites. The hypothesis was that incorporation of the surface‐silanized electrospun nano‐scaled glass fibers into Bis‐GMA/TEGDMA dental composites would result in substantial improvement on mechanical properties. To test the hypothesis, photo‐cured Bis‐GMA/TEGDMA dental composites filled with various mass fractions of surface‐silanized electrospun nano‐scaled glass fibers were systematically fabricated; and their mechanical properties were then evaluated. The results indicated that small mass fraction substitutions (1, 2.5, 5, and 7.5%) of conventional dental filler with the surface‐silanized electrospun nano‐scaled glass fibers, significantly improved the flexural strength, elastic modulus, and work of fracture values of 70% (mass fraction) filled composites, by as much as 44%, 29%, and 66%, respectively. The mechanical properties of the composites could be further improved by optimizing the chemical compositions and the surface treatment methods of the fibers. We envision that the electrospun nano‐scaled glass fibers could be utilized to develop the next generation dental composites, which would be particularly useful for large posterior restorations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Tuning the ensemble selection process of schema matchers

Schema matching is the task of providing correspondences between concepts describing the meaning of data in various heterogeneous, distributed data sources. It is recognized to be one of the basic operations required by the process of data and schema integration and its outcome serves in many tasks such as targeted content delivery and view integration. Schema matching research has been going on for more than 25 years now. An interesting research topic, that was largely left untouched involves the automatic selection of schema matchers to an ensemble, a set of schema matchers. To the best of our knowledge, none of the existing algorithmic solutions offer such a selection feature. In this paper we provide a thorough investigation of this research topic. We introduce a new heuristic, Schema Matcher Boosting (SMB). We show that SMB has the ability to choose among schema matchers and to tune their importance. As such, SMB introduces a new promise for schema matcher designers. Instead of trying to design a perfect schema matcher, a designer can instead focus on finding better than random schema matchers. For the effective utilization of SMB, we propose a complementary approach to the design of new schema matchers. We separate schema matchers into first-line and second-line matchers. First-line schema matchers were designed by-and-large as applications of existing works in other areas (e.g., machine learning and information retrieval) to schemata. Second-line schema matchers operate on the outcome of other schema matchers to improve their original outcome. SMB selects matcher pairs, where each pair contains a first-line matcher and a second-line matcher. We run a thorough set of experiments to analyze SMB ability to effectively choose schema matchers and show that SMB performs better than other, state-of-the-art ensemble matchers.     

Mesh segmentation using feature point and core extraction

Mesh segmentation has become a necessary ingredient in many applications in computer graphics. This paper proposes a novel hierarchical mesh segmentation algorithm, which is based on new methods for prominent feature point and core extraction. The algorithm has several benefits. First, it is invariant both to the pose of the model and to different proportions between the model’s components. Second, it produces correct hierarchical segmentations of meshes, both in the coarse levels of the hierarchy and in the fine levels, where tiny segments are extracted. Finally, the boundaries between the segments go along the natural seams of the models.     

Hybrid Proton and Electron Transport in Peptide Fibrils

Protons and electrons are being exploited in different natural charge transfer processes. Both types of charge carriers could be, therefore, responsible for charge transport in biomimetic self‐assembled peptide nanostructures. The relative contribution of each type of charge carrier is studied in the present work for fibrils self‐assembled from amyloid‐β derived peptide molecules, in which two non‐natural thiophene‐based amino acids are included. It is shown that under low humidity conditions both electrons and protons contribute to the conduction, with current ratio of 1:2 respectively, while at higher relative humidity proton transport dominates the conductance. This hybrid conduction behavior leads to a bimodal exponential dependence of the conductance on the relative humidity. Furthermore, in both cases the conductance is shown to be affected by the peptide folding state under the entire relative humidity range. This unique hybrid conductivity behavior makes self‐assembled peptide nanostructures powerful building blocks for the construction of electric devices that could use either or both types of charge carriers for their function.     

Excitatory-inhibitory network in the visual cortex: psychophysical evidence

At early stages in visual processing cells respond to local stimuli with specific features such as orientation and spatial frequency. Although the receptive fields of these cells have been thought to be local and independent, recent physiological and psychophysical evidence has accumulated, indicating that the cells participate in a rich network of local connections. Thus, these local processing units can integrate information over much larger parts of the visual field; the pattern of their response to a stimulus apparently depends on the context presented. To explore the pattern of lateral interactions in human visual cortex under different context conditions we used a novel chain lateral masking detection paradigm, in which human observers performed a detection task in the presence of different length chains of high-contrast-flanked Gabor signals. The results indicated a nonmonotonic relation of the detection threshold with the number of flankers. Remote flankers had a stronger effect on target detection when the space between them was filled with other flankers, indicating that the detection threshold is caused by dynamics of large neuronal populations in the neocortex, with a major interplay between excitation and inhibition. We considered a model of the primary visual cortex as a network consisting of excitatory and inhibitory cell populations, with both short- and long-range interactions. The model exhibited a behavior similar to the experimental results throughout a range of parameters. Experimental and modeling results indicated that long-range connections play an important role in visual perception, possibly mediating the effects of context.     

Free‐Standing,Thermostable, Micrometer‐Scale Honeycomb Polymer Films and their Properties

A method of manufacturing free‐standing, micrometer‐scale honeycomb polyetherimide films is reported for the first time. Films are manufactured with a dip‐coating technique under water‐assisted self‐assembly. It is shown that the addition of poly(organosilane/siloxane)s and poly(ethylene glycol) allows the formation of regular honeycomb patterns. The films demonstrated the high thermal stability inherent for polyetherimide. The wetting properties of films are reported. The presence of nanopores was revealed with SEM imaging of the films. The makeup of the films allows their use as asymmetric membranes for reverse osmosis and ultrafiltration.

     

Acute hemodynamic effects of metoprolol +/- nitroglycerin in patients with biopsy-proven lymphocytic myocarditis

This clinical case report demonstrates the clinical effectiveness of a new form of soft tissue mobilization in the treatment of excessive connective tissue fibrosis (scar tissue) around an athlete's injured ankle. The scar tissue was causing the athlete to have pain with activity, pain on palpation of the ankle, decreased range of motion, and loss of function. Surgery and several months of conventional physical therapy failed to alleviate the athlete's symptoms. As a final resort, augmented soft tissue mobilization (ASTM) was administered. ASTM is an alternative nonsurgical treatment modality that is being researched at Performance Dynamics (Muncip, IN). ASTM is a process that uses ergonomically designed instruments that assist therapists in the rapid localization and effective treatment of areas exhibiting excessive soft tissue fibrosis. This is followed by a stretching and strengthening program. Upon the completion of 6 wk of ASTM therapy, the athlete had no pain and had regained full range of motion and function. This case report is an example of how a noninvasive augmented form of soft tissue mobilization (ASTM) demonstrated impressive clinical results in treating a condition caused by connective tissue fibrosis.