Effects of depleting ionic strength on 31P nuclear magnetic resonance spectra of micellar casein during membrane separation and diafiltration of skim milk

Membrane separation processes used in the concentration and isolation of micellar casein-based milk proteins from skim milk rely on extensive permeation of its soluble serum constituents, especially lactose and minerals. Whereas extensive literature exists on how these processes influence the gross composition of milk proteins, we have little understanding of the effects of such ionic depletion on the core structural unit of micellar casein [i.e., the casein phosphate nanocluster (CPN)]. The ³¹P nuclear magnetic resonance (NMR) is an analytical technique that is capable of identifying soluble and organic forms of phosphate in milk. Thus, our objective was to investigate changes to the ³¹P NMR spectra of skim milk during microfiltration (MF) and diafiltration (DF) by tracking movements in different species of phosphate. In particular, we examined the peak at 1.11 ppm corresponding to inorganic phosphate in the serum, as well as the low-intensity broad signal between 1.5 and 3.0 ppm attributed to casein-associated phosphate in the retentate. The MF concentration and DF using water caused a shift in the relevant ³¹P NMR peak that could be minimized if orthophosphate was added to the DF water. However, this did not resolve the simultaneous change in retentate pH and increased solubilization of micellar casein protein. The addition of calcium in combination with orthophosphate prevented micellar casein solubilization and simultaneously contributed to preservation of the CPN structure, except for overcorrection of retentate pH in the acidic direction. A more complex DF solution, involving a combination of phosphate, calcium, and citrate, succeeded in both CPN and micellar casein structure preservation while maintaining retentate pH in the region of the original milk pH. The combination of ³¹P NMR as an analytical technique and experimental probe during MF/DF processes provided useful insights into changes occurring to CPN while retaining the micellar state of casein.     

Hydrogen wide area monitoring of LH2 releases

The characterization of liquid hydrogen (LH2) releases has been identified as an international research priority to expand the safe use of hydrogen as an energy carrier. The elucidation of LH2 release behavior will require the development of dispersion and other models, guided and validated by empirical field measurements such as those afforded by Hydrogen Wide Area Monitoring (HyWAM). HyWAM can be defined as the quantitative spatial and temporal three-dimensional monitoring of planned or unintentional hydrogen releases. With support provided through the FCH JU Prenormative Research for the Safe Use of Liquid Hydrogen (PRESLHY) program, HSE performed a series of LH2 releases to characterize the dispersion and pooling behavior of cold hydrogen releases. The NREL Sensor Laboratory developed a HyWAM system based upon a distributed array of point sensors that is amenable for profiling cold hydrogen plumes. The NREL Sensor Laboratory and HSE formally committed to collaborate on profiling the LH2 releases. This collaboration included the integration of the NREL HyWAM into the HSE LH2 release hardware. This was achieved through a deployment plan jointly developed by the NREL and HSE personnel. Under this plan, the NREL Sensor Laboratory provided multiple HyWAM modules that accommodated 32 sampling points for near-field hydrogen profiling during the HSE PRESLHY LH2 releases. The NREL HyWAM would be utilized throughout the LH2 release study performed under PRESLHY by HSE, including Work Package 3 (WP3—Release and Mixing--Rainout) and subsequent work packages (WP4—Ignition and WP5—Combustion). Under the auspices of the PRESLHY WP6 (Implementation), data and findings from the HSE LH2 Releases are to be made available to stakeholders in the hydrogen community. Comprehensive data analysis and dissemination is ongoing, but the integration of the NREL HyWAM into the HSE LH2 Release Apparatus and its performance as well as some key outcomes of the LH2 releases in WP3 are presented.     

Influence of chitosan concentration on the stability,microstructure and rheological properties of O/W emulsions formulated with high-oleic sunflower oil and potato protein

Relatively concentrated (40 wt%) O/W emulsions formulated with high-oleic sunflower oil as disperse phase, potato protein isolate as emulsifier and chitosan as stabiliser were prepared by rotor–stator/high-pressure valve/rotor–stator homogenization. The influence of chitosan concentration on the physical stability of emulsions was studied in (0.25–1) wt% range by visual inspection, rheological and microstructural techniques. Steady shear flow curves were sensitive to the occurrence of creaming upon the rise of zero-shear viscosity values. The effect of increasing concentration of chitosan on the zero-shear viscosity turned out to be dependent on emulsion ageing and always resulted in a stepwise increase of the critical shear rate for the onset of shear thinning flow. The critical oscillatory shear stress for the onset of non-linear viscoelastic behaviour was more sensitive than the critical shear rate to detect creaming in emulsions. Mechanical spectra are definitely demonstrated to be the most powerful tool to detect not only creaming but also oil droplet flocculation on account of changes in the plateau relaxation zone. CSLM micrographs supported the interpretation of dynamic viscoelastic results, especially when flocculation as well as coalescence took place. Cryo-SEM micrographs evidenced the formation of increasingly denser protein–polysaccharide networks with chitosan concentration and the fact that the latter governs the microstructure of the emulsion when reaches 1 wt% concentration promoting enhanced physical stability.     

Improved simulated annealing with step width adaptation for Langmuir probe tuning

In a previous investigation, a simulated annealing (SA) method was developed to optimize 14 Fourier terms in a radio-frequency waveform for active compensation of a Langmuir probe system. This approach was shown to find better solutions in less time than skilled human operators. However, variations in fitness indicated that the SA algorithm did not always find the precise global solution, although it came consistently close to it. This variability was caused by the limited number of fitness evaluations available due to time constraints. In this research, the chosen maximum step width has been shown to have a significant effect on the overall performance of the algorithm. A scaling function has been developed to adapt the maximum step width of the SA algorithm, on-line, as a function of the number of elapsed iterations. The modified algorithm has been shown to find fitter solutions with reduced variability in fitness.     

A freeform optics design with limited data for extended LED light sources

Abstract

This paper proposes an optimization method for designing a freeform lens which can produce a good uniform circular illumination distribution and obtain high efficiency on the target plane. The initial surface profile of the freeform lens is calculated based on the laws of reflection and the energy conservation law, and then is fitted using the non-uniform rational basis spline (NURBS) method. The control points and weights are applied to parameterize the shape of freeform lens. The merit function for the optimization is defined as relative standard deviation (RSD) of the simulated illumination from the desired illumination and the efficiency of the lens. The simulation results indicate that the RSD is shown to be lower than 0.157, and maximum efficiency can be as high as 83.9%. In addition, it is demonstrated that this algorithm can obtain high uniform illumination distribution on the target plane with less variables. Compared with the conventional method, the simulation results show that the modified algorithm converges with less variables, good uniformity and high efficiency. Moreover, a freeform lens with different lighting patterns and non-rotational symmetry can be produced by the proposed method.     

The role of experience in the interpretation of noun–noun combinations

Gagné and Shoben’s (J Exp Psychol Learn Mem Cogn 23:71–87, 1997) Competition Among Relations In Nominals (CARIN) theory maintains that the interpretation of modifier-noun combinations is influenced primarily by how the modifying noun has been used in the past. As support for this theory, they found that modifiers typically associated with the instantiated relation are interpreted reliably faster than those whose modifiers are less frequently associated with the relation. The CARIN theory explains this phenomenon by proposing that people store statistical distributions regarding the frequency with which modifying nouns have combined with each relation in the past. However, we maintain that an association between relation frequency and response time does not imply a causal influence. In this study we explore whether the effects observed by Gagné and Shoben were caused by the influence of relation frequency per se. Two experiments were conducted in which experiential knowledge about the modifier was controlled. The first experiment involved combinations whose modifiers were relatively rare and the second involved the presentation of nouns without a modifier-head syntax. In both of these experiments, knowledge about historical modifier usage was irrelevant. Our results show that correlations between modifier preference and response time persist even in situations where a knowledge of the modifier’s history is not available. These findings provide converging evidence that the relationship between relation frequency and response time is not a causal one. Instead, an understanding of the relationship between modifier properties and usage, as appropriate to the given context, may be the dominant influence on interpretation in many circumstances. In light of this, we propose an alternative account of the factors influencing ease of interpretation.     

HDTV全球瞩目数字家电蓬勃发展

随着数字广播电视的发展与下一代光盘的问世,业内各有关厂家都期望北美的H D T V相关市场也能迅速兴旺起来。在年初举行的消费电子产品展览会“2005国际CES”上,以索尼公司为首的众多制造厂家与服务提供商都展出了H D T V相关产品,欲在市场上争得有利位置。各公司均强调要引领H     

Rehabilitation of bedrock stream channels: the effects of boulder weir placement on aquatic habitat and biota

The placement of boulder weirs is a popular method to improve fish habitat, though little is known about the effectiveness of these structures at increasing fish and biota abundance. We examined the effectiveness of boulder weir placement by comparing physical habitat, chemical and biotic metrics in 13 paired treatment (boulder weir placement) and control reaches in seven southwest Oregon watersheds in the summer of 2002 and 2003. Pool area, the number of boulders, total large woody debris (LWD) and LWD forming pools were all significantly higher in treatment than control reaches (p < 0.05). No differences in water chemistry (total N, total P, dissolved organic carbon) or macroinvertebrate metrics (richness, total abundance, benthic index of biotic integrity etc.) were detected. Abundance of juvenile coho salmon (Oncorhynchus kisutch) and trout (O. mykiss and O. clarki) were higher in treatment than control reaches (p < 0.05), while dace (Rhinichthys spp.; p < 0.09) were more abundant in control reaches and no significant difference was detected for young‐of‐year trout (p > 0.20). Both coho salmon and trout response to boulder weir placement were positively correlated with difference in pool area; p < 0.10), while dace and young‐of‐year trout response to boulder weir placement were negatively correlated with difference in LWD (p < 0.05). The placement of boulder weirs appears to be an effective technique for increasing local abundance of species that prefer pools (juvenile coho and trout >100 mm). Based on our results and previous studies on bedrock and incised channels, we suggest that the placement of boulder structures is a useful first step in attempting to restore these types of stream channels. Published in 2006 by John Wiley & Sons, Ltd.     

A reanalysis of the CARIN theory of conceptual combination.

The competition among relations in nominals (CARIN) theory of conceptual combination (C. L. Gagné & E. J. Shoben, 1997) proposes that people interpret nominal compounds by selecting a relation from a pool of competing alternatives and that relation availability is influenced by the frequency with which relations have been previously associated with the modifying concept. The current authors derived relation frequencies by using a sample of compounds occurring in the British National Corpus and compared them with those derived by Gagné and Shoben. The authors demonstrated that the original relation frequencies are unrepresentative and that Gagne' and Shoben's technique for dichotomizing them into high and low is unreliable. In addition, the authors revealed anomalies in the mathematical instantiation of the CARIN model and showed that it does not provide evidence for competition among relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)