Pressure-temperature gelatinization phase diagram of starch: An in situ Fourier transform infrared study

The gelatinization of rice starch is reported as a function of temperature and pressure from the changes in the ir spectrum. The diagram that is observed is reminiscent of those obtained for the denaturation of proteins and the phase separation observed from the cloud point for several water soluble synthetic polymers. It is proposed that the reentrant shape of the diagram for starch is not only due to hydrogen bonding but also to the imperfect packing of amylose and amylopectin chains in the starch granule. The influence of pressure and temperature on thermodynamic parameters leading to this diagram is discussed.     

Protein crystallization and phase diagrams

The phase diagram is a map which represents the state of a material (e.g., solid and liquid) as a function of the ambient conditions (e.g., temperature and concentration). It is therefore a useful tool in processing many different classes of materials. In this article, methods to determine the phase diagram of an aqueous solution of a globular protein are described, focusing on the solid (crystal) and condensed liquid states. The use of the information contained in the phase diagram for protein crystallization is also discussed.     

Pressure-temperature phase diagrams of biomolecules

The pressure-temperature phase diagram of various biomolecules is reviewed. Special attention is focused on the elliptic phase diagram of proteins. The phenomenological thermodynamic theory describing this diagram explains the heat, cold and pressure denaturations in a unified picture. The limitations and possible developments of this theory are discussed as well. It is pointed out that a more complex diagram can be obtained when the intermolecular interactions are also taken into account. In this case metastable states appear on the pressure-temperature (p-T) diagram due to intermolecular interactions. Pressure-temperature phase diagrams of other biopolymers are also discussed. While the p-T diagrams of helix-coil transition of nucleic acids and of gel-liquid crystal transition of lipid bilayers are non-elliptical, those of gelatinization of starch and of phase separation of some synthetic polymers show an elliptic profile, similar to that of proteins. Finally, the p-T diagram of bacterial inactivation is shown to be elliptic. From the point of view of basic science, this fact shows that the key factor of inactivation should be the protein type, and from the viewpoint of practical applications, it serves as the theoretical basis of pressure treatment of biosystems.     

The colour hexagon: a chromaticity diagram based on photoreceptor excitations as a generalized representation of colour opponency

Summary A chromaticity diagram which plots the 3 photoreceptor excitations of trichromatic colour vision systems at an angle of 120° is presented. It takes into acount the nonlinear transduction process in the receptors. The resulting diagram has the outline of an equilateral hexagon. It is demonstrated by geometrical means that excitation values for any type of spectrally opponent mechanism can be read from this diagram if the weighting factors of this mechanism add up to zero. Thus, it may also be regarded as a general representation of colour opponent relations, linking graphically the Young-Helmholtz theory of trichromacy and Hering's concept of opponent colours. It is shown on a geometrical. basis that chromaticity can be coded unequivocally by any two combined spectrally opponent mechanisms, the main difference between particular mechanisms being the extension and compression of certain spectral areas. This type of graphical representation can qualitatively explain the Bezold-Brücke phenomenon. Furthermore, colour hexagon distances may be taken as standardized perceptual colour distance values for trichromatic insects, as is demonstrated by comparison with behavioural colour discrimination data of 3 hymenopteran species.     

Ecological types of running water based on stream hydraulics in The Netherlands

The factors determining life conditions in running waters can be arranged in a hierarchical scheme. One of the main factors is stream velocity, which is described by Manning's formula. By transformation of the formula a set of variables is acquired with which a diagram is constructed to contain all hydraulic conditions in running water. By measuring the ground slope and the hydraulic radius at a certain station this station can be placed in the diagram. Data from Dutch streams and rivers form definite clusters enabling us to describe types of running waters on this base. The distribution patterns of stream organisms in accordance with stream hydraulics can be fit into the diagram as well.     

DISCUSSIONS AROUND A SAND-DRAWING: CREATIONS OF AGENCY AND SOCIETY IN MELANESIA

This article considers the social circumstances of making a marriage diagram, on the island of Ambrym in Vanuatu. It offers a reconsideration of the rather famous case of the 'six-section marriage system' as demonstrated by Cambridge anthropologist Bernard Deacon. It relates this idea of a system to the indigenous practice of making figurative drawings in the sand. The argument is that the marriage diagram drawn for Bernard Deacon was merely an instance of Vanuatu people's institutionalized capability of totalizing social flows and making them into aesthetic shapes.     

Physicochemical properties, binary and ternary phase diagrams of ketoprofen

Compared to simulated moving bed (SMB) chromatography, fractional crystallization is a simple and economical method for enantioseparation. Therefore, the coupling of SMB chromatography and fractional crystallization is suggested for enantioseparation of racemic compounds. In this work, a nonsteroidal antiinflammatory drug, ketoprofen (Kp), was chosen to be studied. Kp was verified as a racemic compound by FTIR, PXRD, and thermodynamic calculations. To derive the condition where pure (S)-Kp could be crystallized from a solution, which was previously enantiomerically enriched, the binary melting phase diagram and the ternary solubility phase diagram in the mixed solvent of ethanol and water over a temperature range of 15-30 degrees C were obtained. From these phase diagrams the eutectic point was determined as 91.6% mole percent (S)-Kp from the binary phase diagram and 91% from the ternary phase diagram. The results may provide valuable experiment data for the possibility of coupling fractional crystallization with SMB for Kp separation.     

基于Voronoi图的林分空间模型及分布格局研究

以南洞庭湖龙虎山次生林为研究对象,建立林分Voronoi图模型,通过该模型表示林分空间结构特征,提取林木空间量化信息。在此基础上,引入变异系数量化Voronoi多边形面积的变化率,将林木空间格局分析转化为计算Voronoi图变异系数,并将计算结果与角尺度作相关性比较。结果表明:林分Voronoi图模型能准确表达林木邻接关系、相邻木距离及角度、空间密度等重要空间信息;大尺度取样时(76m以上),变异系数趋于稳定,林分整体空间格局呈接近随机分布的轻度聚集;Voronoi图变异系数和角尺度存在显著的正相关关系,进一步说明本研究格局分析方法的可行性和有效性;受多种因素影响,乔木层主要树种在不同发育阶段的空间格局表现出强烈的时间和空间动态特性,且小径木多为聚集分布,大径木呈轻度聚集或随机分布。基于Voronoi图的林分空间模型及格局分析方法,从空间上表征林木的生长繁育特性、种内种间关系、资源及环境分布特征,为计算几何方法应用于林分空间经营提供了新的思路。     

Colorimetry for the Stain Technologist. II. The Specification of Chromaticity Difference

This paper describes the calculation of chromaticity difference. The text has been written specifically for the stain technologist and is largely self-contained. The concept of a uniform chromaticity scale (UCS) is described. A UCS is a diagram in which equal perceived differences in chromaticity are represented by equal distances anywhere on the diagram. UCSs are developed by transformations of the CIE 1931 chromaticity diagram, and may be linear (projective) or nonlinear. The effectiveness of the various transformations has been assessed using published data on discrimination of chromaticity. The usefulness of chromaticity difference calculations is illustrated by histological examples, including Romanowsky stained blood cells and Papanicolaou stained cells from the uterine cervix. Six UCSs are used in these examples, two projective and four nonlinear.     

An S-Curve-Based Approach of Identifying Biological Sequences

The main idea of S-curve diagram is to assign different angle values (from 0° to 180°) to different nucleotide acid residues or to different protein amino acids, and then according to cos α _j and sin α _j , the values are accumulated to construct an S-curve diagram, which is in strict one-to-one correspondence with the biological sequence. In addition, the S-curve diagram proves to be without the degeneracy phenomenon, so that both the degeneracy problem represented by diagrams and the problem of visualization for biological sequence data are solved. Meanwhile, a new approach to differentiate the similarity of biological sequences—the degree of similarity—is put forward on the basis of the S-curve diagram. To put it in detail, the least square approach is first adopted to obtain a straight line equation according to the S-curve diagram, then according to the distance formula of the point to the straight line, the average ratio of square sum for the distance between the S-curve and the straight line is calculated, and finally, the similarity of the biological sequences is presented by the new standard—the degree of similarity. As is shown by the experimental results, the S-curve diagram can better represent biological sequences (such as protein’s) within Cartesian coordinate system, and the mutation point of biological sequence. Thus, it turns out that the new standard—the degree of similarity is of obviously great advantage.     

The assembly of ionic currents in a thalamic neuron. I. The three-dimensional model

We have previously discussed qualitative models for bursting and thalamic neurons that were obtained by modifying a simple two-dimensional model for repetitive firing. In this paper we report the results of making a similar sequence of modifications to a more elaborate six-dimensional model of repetitive firing which is based on the Hodgkin-Huxley equations. To do this we first reduce the six-dimensional model to a two-dimensional model that resembles our original two-dimensional qualitative model. This is achieved by defining a new variable, which we call q. We then add a subthreshold inward current and a subthreshold outward current having a variable, z, that changes slowly. This gives a three-dimensional (v,q,z) model of the Hodgkin-Huxley type, which we refer to as the z-model. Depending on the choice of parameter values this model resembles our previous models of bursting and thalamic neurons. At each stage in the development of these models we return to the corresponding seven-dimensional model to confirm that we can obtain similar solutions by using the complete system of equations. The analysis of the three-dimensional model involves a state diagram and a stability diagram. The state diagram shows the projection of the phase path from v,q,z space into the v,z plane, together with the projections of the curves z = 0 and v = q = 0. The stability of the points on the curve v = q = 0, which we call the v, q nullcurve, is determined by the stability diagram. Taken together the state and stability diagrams show how to assemble the ionic currents to produce a given firing pattern.     

Integrating multiple signals into cell decisions by networks of protein modification cycles

Posttranslational protein modifications play a key role in regulating cellular processes. We present a general model of reversible protein modification networks and demonstrate that a single protein modified by several enzymes is capable of integrating multiple signals into robust digital decisions by switching between multiple forms that can activate distinct cellular processes. First we consider two competing protein modification cycles and show that in the saturated regime, the protein is concentrated into a single form determined by the enzyme activities. We generalize this to protein modification networks with tree structure controlled by multiple enzymes that can be characterized by their phase diagram, which is a partition of the space of enzyme activities into regions corresponding to different dominant forms. We show that the phase diagram can be obtained analytically from the wiring diagram of the modification network by recursively solving a set of balance equations for the steady-state distributions and then applying a positivity condition to determine the regions corresponding to different responses. We also implement this method in a computer algebra system that automatically generates the phase diagram as a set of inequalities. Based on this theoretical framework, we determine some general properties of protein modification systems.     

Computer vision for LCA foreground modelling—an initial pipeline and proof of concept software,lcopt-cv

Purpose

The majority of LCA studies begin with the drawing of a process flow diagram, which then needs to be translated manually into an LCA model. This study presents an initial image processing pipeline, implemented in an open-source software package, called lcopt-cv, which can be used to identify the boxes and links in a photograph of a hand-drawn process flow diagram and automatically create an LCA foreground model.

Methods

The computer vision pipeline consists of a total of 15 steps, beginning with loading the image file and conversion to greyscale. The background is equalised, then the foreground of the image is extracted from the background using thresholding. The lines are then dilated and closed to account for drawing errors. Contours in the image are detected and simplified, and rectangles (contours with four corners) are identified from the simplified contours as ‘boxes’. Links between these boxes are identified using a flood-filling technique. Heuristic processing, based on knowledge of common practice in drawing of process flow diagrams, is then performed to more accurately identify the typology of the identified boxes and the direction of the links between them.

Results and discussion

The performance of the image processing pipeline was tested on four flow diagrams of increasing difficulty: one simple computer drawn diagram and three photographs of hand-drawn diagrams (a simple diagram, a complex diagram and a diagram with merged lines). A set of default values for the variables which define the pipeline was developed through trial and error. For the two simple flow charts, all boxes and links were identified using the default settings. The complex diagram required minor tweaks to the default values to detect all boxes and links. An ‘unstacking’ heuristic allowed the diagram with merged lines to be correctly processed. After some manual reclassification of link directions and process types, the diagrams were turned into LCA models and exported to open-source LCA software packages (lcopt and Brightway) to be verified and analysed.

Conclusions

This study demonstrates that it is possible to generate a fully functional LCA model from a picture of a flow chart. This has potentially important implications not only for LCA practitioners as a whole, but in particular for the teaching of LCA. Skipping the steep learning curve required by most LCA software packages allows teachers to focus on important LCA concepts, while participants maintain the benefits of experiential learning by doing a ‘real’ LCA.

     

Surface Reconstruction through Poisson Disk Sampling

This paper intends to generate the approximate Voronoi diagram in the geodesic metric for some unbiased samples selected from original points. The mesh model of seeds is then constructed on basis of the Voronoi diagram. Rather than constructing the Voronoi diagram for all original points, the proposed strategy is to run around the obstacle that the geodesic distances among neighboring points are sensitive to nearest neighbor definition. It is obvious that the reconstructed model is the level of detail of original points. Hence, our main motivation is to deal with the redundant scattered points. In implementation, Poisson disk sampling is taken to select seeds and helps to produce the Voronoi diagram. Adaptive reconstructions can be achieved by slightly changing the uniform strategy in selecting seeds. Behaviors of this method are investigated and accuracy evaluations are done. Experimental results show the proposed method is reliable and effective.     

The potential diagram for oxygen at pH 7.

Successive one-electron reductions of molecular oxygen yield the superoxide radical (O2-) H2O2, the hydroxyl radical (OH) and water. Redox potentials at pH 7 for one-, two- and four-electron couples involving these states are presented as a potential diagram. The significance of each of these potentials is explained. The complete potential diagram enables complex systems to be rationalized, such as production of OH by H2O2 plus Fe3+.     

Flux ratios and pump stoichiometries at sites II and III in liver mitochondria. Effect of slips and leaks.

Addition of bovine serum albumin to state 4 mitochondria results in a depression of the proton leak and of the resting respiration of 70 and 25%, respectively. The conductance membrane potential diagram, both in the ohmic and in the non-ohmic region, shows that in the presence of bovine serum albumin the level of ohmic conductance is lowered while that of non-ohmic conductance is increased toward higher delta psi values. The same effect is observed during operation of the different proton pumps. Addition of chloroform affects the conductance membrane potential diagram in the following manner: there is no effect in the ohmic region with all pumps, while there is an effect in the non-ohmic region either at site III or at sites II plus III but not at site II. This suggests a possible effect of chloroform at the level of the cytochrome oxidase proton pump. During titration with oligomycin of the ATPase proton pump the conductance potential diagram shows a region of non-ohmicity only in the presence but not in the absence of an ATP-regenerating system. Protonophoric uncouplers such as carbonyl cyanide p(trifluoromethoxy)phenylhydrazone and intrinsic uncouplers such as chloroform have different effects on the relationship between rates of charge translocation and of oxygen consumption, and thus on the pump stoichiometries, in that the slope of the diagram is modified by the latter but not by the former. The differential effects of protonophores and of intrinsic uncouplers on the stoichiometries have been analyzed by computer simulations and represent an additional criterion to distinguish between extrinsic and intrinsic mechanisms of uncoupling.     

Protein stability and dynamics in the pressure-temperature plane

The pressure-temperature stability diagram of proteins and the underlying assumptions of the elliptical shape of the diagram are discussed. Possible extensions, such as aggregation and fibril formation, are considered. An important experimental observation is the extreme pressure stability of the mature fibrils. Molecular origins of the diagram in terms of models of the partial molar volume of a protein focus on cavities and hydration. Changes in thermal expansivity, compressibility and heat capacity in terms of fluctuations of the enthalpy and volume change of the unfolding should also focus on these parameters. It is argued that the study of water-soluble polymers might further our understanding of the stability diagram. Whereas the role of water in protein behaviour is unquestioned, the role of cavities is less clear.     

A new representation of protein structure: vector diagram

A vector diagram was devised for representation of protein structure.This was done by giving each nucleic acid triplet a correspondingvector, and expressing a protein as a set of vectors which werealigned in the order of peptide sequence. The magnitude of eachvector was made to reflect the hydrophilicity of amino acid,and the direction of the vector was chosen so that similar aminoacids had similar directions. The diagram not only shows theprimary sequence but suggests the folding stucture of proteins. Received on November 15, 1985; accepted on March 3, 1986     

A novel strategy for identification of 47 pomegranate (Punica granatum) cultivars using RAPD markers

DNA marker can be used for precise plant cultivar identification. However, DNA markers have often not been used effectively for the identification of plant cultivars due to a lack of an effective analysis strategy. We used a novel strategy for effective identification of plant individuals based on a new way of recording DNA fingerprints of the genotyped plants; a cultivar identification diagram can be manually generated and used as key reference information for quick identification of plant and/or seed samples. Forty-seven pomegranate varieties popularly cultivated in various provinces of China were subjected to RAPD marker analysis. Using the cultivar identification diagram strategy, they were clearly separated by the fingerprints of 11 RAPD primers. The utility and accuracy of the cultivar identification diagram analysis results were confirmed by the identification of three randomly chosen groups of cultivars among the 47 varieties.     

Development and Evaluation of Emulsions from <Emphasis Type="Italic">Carapa guianensis</Emphasis> (Andiroba) Oil

Carapa guianensis, a popular medicinal plant known as “Andiroba” in Brazil, has been used in traditional medicine as an insect repellent and anti-inflammatory product. Additionally, this seed oil has been reported in the literature as a repellent against Aedes aegypti. The aim of this work is to report on the emulsification of vegetable oils such as “Andiroba” oil by using a blend of nonionic surfactants (Span 80® and Tween 20®), using the critical hydrophilic–lipophilic balance (HLB) and pseudo-ternary diagram as tools to evaluate the system’s stability. The emulsions were prepared by the inverse phase method. Several formulations were made according to a HLB spreadsheet design (from 4.3 to 16.7), and the products were stored at 25°C and 4°C. The emulsion stabilities were tested both long- and short-term, and the more stable one was used for the pseudo-ternary diagram study. The emulsions were successfully obtained by a couple of surfactants, and the HLB analysis showed that the required HLB of the oil was 16.7. To conclude, the pseudo-ternary diagram identified several characteristic regions such as emulsion, micro-emulsion, and separation of phases.