Volume Of Granules Research Articles

Exogenous Application of Abscisic Acid or Gibberellin Acid Has Different Effects on Starch Granule Size Distribution in Grains of Wheat

Granule size distribution of wheat starch is an important characteristic that can affect its chemical composition and the functionality of wheat products. Two high-yield winter wheat cultivars were used to evaluate the effects of the application of exogenous ABA or GA during the reproductive phase of the initial grain filling on starch granule size distribution and starch components in grains at maturity. The results indicated that a bimodal curve was found in the volume and surface area distribution of grain starch granules, and a unimodal curve was observed for the number distribution under all treatments. The exogenous ABA resulted in a significant increase in the proportions (both by volume and by surface area) of B-type (<9.9 μm in diameter) starch granules, with a reduction in those of A-type (>9.9 μm) starch granules, while, the exogenous GA3 led to converse effects on size distribution of those starch granules. The exogenous ABA also increased starch, amylose and amylopectin contents at maturity but significantly reduced the ratio of amylose to amylopectin. Application of GA3 significantly reduced starch content, amylopectin content but increased the ratio of amylose to amylopectin. The ratio of amylose to amylopectin showed a significant and negative relationship with the volume proportion of granules <9.9 μm, but was positively related to the volume proportion of granules 22.8-42.8 μm.

Formulasi Bioinsectisida Dari Bakteri Bacillus Thuringiensis

Among the pathogenic bacteria, Bacillus Thuringiensis is the one of potential bacterial insecticides which has the capability in crystallizing protein in the cell as an entomoxcyn or active agent of bioinsecticides. The advantages of bioinsecticides usage are toxic only to the insect target, and it is net creating bioinsecticides are toxic. The commercial form of Bacillus Thuringiensis is made from the active bacteria agent as mixing of spora and protein crystal and carrier. The active bacteria agent prepared by two kinds of fermentation methods, sub merged fermentation and semi solid fermentation. There are 7 bioinsecticide form available in Indonesia such as Granule, Flowable Concentrate, Wettable Powder, Suspension, Aqueous Suspension, Water Dispersible Granule and Ultra Low Volume. There product are not produce yet in Indonesia, just repacking for commercial purposes.

Differences of Starch Granules in Grains from Different Spikelet Positions and Their Correlation with Grain Weight in Winter Wheat

The purpose of this study was to reveal the differences in development and size-distribution of starch granules in endosperm of wheat grains in different grain positions and spikelet positions. The endosperm cell size, and the number, volume and surface area distribution of starch granules in mature caryopsis, as well as the changes of starch granule number during endosperm development, were studied using wheat cultivar Jimai 20 grown in the field. The results showed that the development of starch granule was closely related with grain position and spikelet position. In the same spikelet position, starch grains formed 4–5 d earlier in superior grains (the first and the second grains) than in inferior grains (the third and the fourth grains).At the same grain position, starch granules developed first in the grains of the middle spikelets, and then in grains of upper and lower spikelets. The amount of starch granules was the highest in the middle spikelet grains all the time. The lower spikelet grains had the least starch granules at the beginning of grain filling, however, the number of starch granules increased gradually and surpassed that of the upper spikelet grains as caryopsis matured. Correlation coefficients between grain weight and starch granule amount became more significant with grain filling, which reached 0.88 ** (large starch granule) and 0.78 ** (small starch granule) at mature stage. Correlation coefficients between grain weight and large starch granule amount were higher than 0.96 ** , and had no difference among different spikelet positions. Correlation coefficients between grain weight and small starch granule amount were higher than 0.93 ** , and had a trend of upperlowermiddle in different spikelet positions. The trend of size distribution was BL-typeBS-typeA-type. There were more BS-type granules in superior grains than in inferior grains. The number of BS-type granules increased with the spikelet position rising, whereas the number of BL-type granules showed a reverse trend. The size distribution of starch granules had similar changes to volume and surface area. The formation and size distribution of starch granules were affectedsignificantly by grain position and spikelet position, and inferior grains had the potential of increasing grain weight through increasing the quantity of starch granules.

Activated effect of lignin on α-amylase

This paper reports a new kind of activator of α-amylase, lignin, which can greatly increase α-amylase activity. The promoted ratio of lignin is even much higher than that of chloride ion, the traditional activator of α-amylase. Further experimental results reveal that lignin may interact with α-amylase to form a 1:1 complex with a binding constant of 4.47×105M−1. The binding is spontaneous and lignin/α-amylase complex formation is an exothermal reaction. Hydrogen bonding plays a key role and non-radiation energy transfers from α-amylase to lignin in the binding process. Lignin, combining with α-amylase, conforms to a first-order exponential decay function. The formation of the lignin/α-amylase complex results in the reduction of α-helical content from 57.7% to 53.9%, the increase of the polarity around tryptophan residues, the decrease of the hydrophobicity, and the enlargement of protein granule volume. This work will give a deeper insight into lignin as a kind of dietary fibre, known as an important food functional factor. Furthermore, it also contributes to the exploration of an activator of α-amylase, used in the food industry.

Agglomeration behaviour and product structure of clay and oxide minerals

Agglomeration of fine mineral particle into robust and porous granules is an essential precursor to heap leaching and valuable metal recovery from low grade lateritic ores. In this paper, isothermal, batch agglomeration behavior of selected model clay (kaolinite and smectite) and oxide (hematite and quartz) minerals which constitute the predominant host gangue phases of typical low-grade nickel (Ni) lateritic ores is investigated. Specifically, the influential role of feed particle size and mineralogy on H2SO4 binder dosage requirement and agglomeration behavior was studied. Granules of 5–40mm size range were produced within 8–14min and their mechanical/structural properties examined. The results showed that for equivalent wetting and saturation, finer feed particles required higher binder dosage and led to dry agglomerates of higher compressive strength and re-wetting stability in acidic solution than coarser feed particles. Furthermore, binder dosages required for effective agglomeration were greater for the clays than the oxide minerals. Quartz, kaolinite and smectite displayed markedly slower growth behavior in comparison with hematite. The internal micro-structural analysis showed that the pore volumes (porosities) of the oxide granules were noticeably more than those of the clay granules these increased markedly (20–30% for clays and 30–40% for oxides) upon drying due to stresses/strains resulting from particle shrinkage after solvent (water) loss. Agglomerate dry compressive strengths for kaolinite and hematite were found to be similar and greater than those for quartz and smectite whilst the corresponding re-wetting stability decreased in the order: kaolinite>quartz>hematite=smectite. These findings, which indicate that the correlation between granule mineralogy, structural and behavior is quite complex, provide a useful basis for benchmarking the agglomeration behavior and granule properties of lateritic mineral ores.

Chromogranin Location in the Adrenal Glands of ISIAH Rats

Comparative immunohistochemical and electron microscopic study of the adrenals from hypertensive ISIAH rats and normotensive WAG rats (control) showed a more intense reaction to chromogranin A in the ISIAH adrenal in comparison with the control. Electron microscopy and morphometric analysis showed high volume and numerical densities of the secretory granules in chromaffin cells of hypertensive rats. The results indicate stimulation of the adrenal medullary substance in ISIAH rats. Presumably, intensive accumulation of chromogranin A and secretory granules in chromaffin cells of hypertensive rats reflects a certain imbalance of chromogranin A and catecholamines biogenesis, this, in turn, leading to stable stimulation of the sympathoadrenal component and higher stress sensitivity of these animals.

Ultrastructural morphometric analysis of insulin secretory granules in human type 2 diabetes

We performed an ultrastructural morphometric analysis of insulin secretory granules in pancreatic beta cells from control and type 2 diabetic multiorgan donors. The volume density of insulin granules significantly (p < 0.05) reduced in beta cells from type 2 diabetic patients with respect to non-diabetic subjects, and this reduction was mainly attributable to a decrease in mature granules. On the contrary, no significant difference was observed in the volume density of docked granules between controls and type 2 diabetic patients. In addition, there was a significant positive correlation between the density volume of total insulin granules and stimulated insulin secretion in non-diabetic islets. In conclusion, we detected significant changes in the intracellular distribution of insulin secretory granules within the beta cell that might be related with the alterations in insulin secretion observed in type 2 diabetes patients.

Granular modelling of signals: A framework of Granular Computing

In spite of the evident diversity of models of signals and time series, there is still an urgent need to develop constructs that are both accurate and highly interpretable (human-centric). While a great deal of research has been devoted to the design of nonlinear models of time series (with anticipation of achieving high accuracy of prediction), an issue of interpretability (transparency) of the models remains an evident and ongoing challenge. The user-friendliness of models of time series comes hand in hand with an ability of humans to perceive and process abstract entities rather than plain numeric entities. With this regard, information granules and Granular Computing play an essential role. The use of information granules gives rise to a concept of granular models of time series or granular models of signals and time series, in brief. A granular interpretation of temporal data, where the role of information granularity is of paramount interest and effectively supports a human-centric description of relationships existing within data. This study revisits generic concepts of information granules and Granular Computing in this setting and elaborates on a fundamental way of forming information granules (both sets – intervals as well as fuzzy sets) through applying a principle of justifiable granularity. The granular representation of time series is then discussed with a number of representation alternatives. A question of forming adjustable temporal slices (time windows) using which information granules are formed is discussed. With this regard presented is an optimization criterion of a sum of volumes of information granules whose minimization is realized through some methods of evolutionary or population-based optimization techniques. A series of illustrative examples is also discussed.

Examination of PHB Depolymerases in Ralstonia eutropha: Further Elucidation of the Roles of Enzymes in PHB Homeostasis.

Polyhydroxyalkanoates (PHA) are biodegradable polymers that are attractive materials for use in tissue engineering and medical device manufacturing. Ralstonia eutropha is regarded as the model organism for PHA biosynthesis. We examined the effects of PHA depolymerase (PhaZ) expression on PHA homeostasis in R. eutropha strains. In order to analyze the impact of PhaZs on R. eutropha granule architecture, we performed electron microscopy on several phaZ knockout strains and the wild type strain grown under PHA production conditions. Analysis of the acquired micrographs was based on stereology: the ratio of granule area and cell area was determined, along with total granule count per full-size cell image. Cells bearing a phaZ2 knockout mutation alone or in conjunction with a phaZ1 mutation were found to have a high granule volume per cell volume and a higher granule count compared to wild type. A phaZ quadruple knockout strain appeared to have a low granule volume per cell volume and a low granule count per cell. Cells bearing a phaZ3 knockout were found to have a higher granule count than the wild type, whereas granule volume per cell volume was similar. Accordingly, we hypothesize that PhaZs have not only an impact on PHA degradation but also on the 3-dimensional granule architecture. Based on our data, PhaZ2 is postulated to affect granule density. This work increased our knowledge about PHA depolymerases in R. eutropha, including enzymes that had previously been uncharacterized.

Shading after anthesis in wheat influences the amount and relative composition of grain proteins

SUMMARYThe high molecular weight glutenin subunits (HMW-GS) and glutenin macropolymer (GMP) in wheat grain are important characteristics that affect the quality of wheat products. Light intensity, as one of the environmental factors affecting grain yield and quality, has been studied extensively; however, little is known about its impact on HMW-GS and distribution of GMP granules in wheat grain. In the present study, two strong-gluten winter wheat cultivars with different subunit compositions were used to evaluate the effect of shading at different grain-filling stages on changes in HMW-GS and distribution of GMP granules in wheat grains. No effects of shading on initial formation time of each individual subunit were found; they responded similarly to shading with an increase in relative content, though the accumulation amount per grain of each individual subunit was decreased due to a decrease in grain weight induced by shading. Shading at different grain-filling stages, especially at the middle grain-filling stage, led to a significant increase in GMP content during grain filling; however, the proportions (by volume, number and surface area) of the larger GMP granules were increased by shading at middle and late grain-filling stages and decreased by shading at early grain-filling stage. It was also found that the content of total HMW-GS was positively correlated with volume proportions of larger GMP granules and negatively correlated with volume proportions of small GMP granules, which indicated that the pattern of response of distribution of GMP granules to shading was closely related to the regulatory effect of shading on the HMW-GS.

Pre-anthesis high temperature acclimation alleviates the negative effects of post-anthesis heat stress on stem stored carbohydrates remobilization and grain starch accumulation in wheat

The potential role of pre-anthesis high temperature acclimation in alleviating the negative effects of post-anthesis heat stress on stem stored carbohydrate remobilization and grain starch accumulation in wheat was investigated. The treatments included no heat-stress (CC), heat stress at pre-anthesis only (HC), heat at post-anthesis only (CH), and heat stress at both stages (HH). Post-anthesis heat stress decreased grain starch content, reduced the content of fructans and depressed activities of related synthesis enzymes of sucrose:sucrose fructosyltransferase and fructan:fructan fructosyltransferase. Interestingly, HH plants had significantly higher grain yield than the CH plants. In addition, post-anthesis high temperature lowered grain starch content and increased percentages of volume, number and surface area of B-type starch granules in CH and HH than in CC treatment. However, HH plants had much higher starch content, and caused less modified B-type starch granule size indicators than the CH plants. Our results indicated that, compared with the non-acclimated plants, the pre-anthesis high temperature acclimation effectively enhanced carbohydrate remobilization from stems to grains, led to less changed starch content and starch granule size distribution in grains of wheat under post-anthesis heat stress.

압밀과 포화수준에 따른 분쇄 Coir 혼합 펄라이트의 수분보유력과 수리전도도

This investigation was performed to determine the hydraulic conductivity coefficient and water holding capacity for a specified compaction forces which are the amount of mechanical energy applied to the porous granule (PG) volume. Most current specifications of minerals and perlite as growth media require to be compacted to a specified density, which in general is equivalent to a certain percentage of laboratory compaction. The water holding capacity of the saturated PG was very large at potential above -1 bar compared with perlite, but very little water remained below this value. The water holding capacity and hydraulic conductivity characteristics of graded PG amended with the ground coir less than 2 mm in diameter were also determined from pressure outflow data. The saturated hydraulic conductivity of the saturated and compacted PG was slightly lower by more than one tenth order of magnitude at equal matric potentials of perlite, but when expressed on the basis of equal water deficits, the conductivity of PG was higher at all but the smallest deficits than those of perlite.

Effects of drought stress on seed sink strength and leaf protein patterns of common bean genotypes

Assimilate availability and the capacity to utilise them in the reproductive structures to a large extent determine reproductive sink establishment and yield of crops under drought stress. This study was carried out to investigate the effect of drought stress imposed at early pod-fill stage on seed sink strength of common bean (Phaseolus vulgaris L.) genotypes differing in drought resistance. Quantitative and qualitative changes in leaf protein patterns was assessed using 2D-gel electrophoresis. A drought-resistant inbred line (SEA 15) and a droughtsusceptible cultivar (BrSp) were grown under non-stress and drought stress conditions in a vegetation hall during the summer of 2004. Drought stress commenced at early pod-filling stage caused 53 and 30% seed yield reductions in BrSp and SEA 15, respectively. The effect of drought on seed yield was primarily due to the significant reduction in number of seeds per plant (48% for BrSp vs. 35% for SEA 15). Whereas seed sucrose concentrations of BrSp decreased by 29 to 47% under drought conditions, the stress resulted in an increase (up to 43%) in concentration of the carbohydrate in SEA 15 seeds. Despite the genotypic difference found for seed sucrose import, seed starch accumulations of the two genotypes decreased under drought stress. For both genotypes, none of the seed sink capacity parameters (numbers and volumes of cotyledonary cells and starch granules per seed) were significantly affected by the stress imposed implying that the drought-induced decrease in seed starch accumulation could be due to limitations in assimilate availability and/or other sink activity factors within theseed. A total of 230 leaf proteins were differentially expressed due to drought out of which 23.5, 15.1, 4.3 and 3.5% were down-regulated, up-regulated, newly appeared and disappeared, respectively. Identification and assigning possible functions in the crop’s response to drought of the stress-induced proteins warrant further study

Effects of Shading at Different Stages After Anthesis on Maize Grain Weight and Quality at Cytology Level

Abstract The objective of the current study is to investigate the effects of different stages of shading after anthesis on grain weight and quality of maize at cytology level. The shading experiments were conducted in the field from 2005 to 2006, with a common maize cultivar (TY2) as the experimental material. Plants were given stress using horizontal shading net and the light intensity was reduced by 55%. Field-grown maize plants were shaded at 1-14 d (SI), 15-28 d (S2), and 29-42 d (S3) after pollination, respectively. Control plants (SO) were grown under natural light. Grain weight, quality, endosperm cell proliferation, cob sugar content, and grain pedicel vascular bundle cross section area were measured. The ultrastructural changes of endosperm cells and endosperm transfer cells were observed after pollination. The result indicated that the grain weight, starch content, endosperm cell number, and volume were declined after shading. On the contrary, the proportion of embryo and endosperm, protein content, and fat content in grain increased. Shading treatments significantly delayed the development of the starch granules and remarkably reduced the endosperm filling status. Among the three treatments, the number of the grain endosperm was the least under shading stress at 1-14 d after pollination. However, the volume of starch granules and the substantiation of endosperm under shading treatment at 15-28 d after pollination were the worst. Compared with the control (natural sunlight without shading), the soluble sugar of maize cob increased significantly, while there was no obvious change in vascular structure of small cluster stalk. The number of protein body in maize endosperm was influenced markedly by low light at different stages after pollination. Low light decreased the volume of the grain endosperm transfer and the cell wall extensions of the basal transfer cells became thinner and shorter under shading treatment than those of the control. Furthermore, the degree of connection and the capacity of the nutrient transport were decreased and the mitochondrion number of the transfer cell was reduced after shading. The change in grain quality after shading was observed due to increase in the proportion of embryo and endosperm. The morphology and functions in endosperm transfer cell and the shortage of energy restricted the nutrient transport greatly with shading at different stages, suggesting that an impeded flux may be one of the important reasons for the reduction of maize grain weight of maize grain at later growth stage under low light condition.

Ultrafine particles of bismuth(III) compounds in the phase of crosslinked polymers: Precursors for new sorbents and catalysts

In this article, we show that strongly basic anion exchangers (AV-17 and Purolite A-400) are able to retain Bi(III)-containing cations from Bi(NO3)3 solutions. The sorption isotherms of the cations at 30 and 50°C were obtained. The sorption increased with increasing temperature. Scanning electron microscopy showed that in the polymer phase, ultrafine particles of Bi(III)-containing compounds were formed. On heating (87°C) in water and in an Na2SO4 solution, Bi(III)-containing ultrafine particles became relatively massive. Powder X-ray diffraction showed the existence of the crystalline phase of BiOCl and Bi2O3 on the surface and in the volume of the polymer granules. The behavior of the Bi(III)-containing polymer in the HCl, HNO3, and H2SO4 solutions (pH 0–2.5) was investigated. The Bi(III)-containing compounds in the polymer phase were stable at pH > 2. The desorption degree of Bi3+ in the HNO3 solution was much greater than in the HCl or H2SO4 solutions. Thermogravimetric investigation (in an N2 atmosphere) in the range 25–1000°C of the Bi(III)-containing polymer was also carried out. The Bi(III)-containing polymer was stable up to 120°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Localization of anionic constituents in mast cell granules of brachymorphic (bm/bm) mice by using avidin-conjugated colloidal gold

We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky's fixative and OsO(4) and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower avidin gold binding density (by approximately 50%, P<0.001). The latter result provided additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild-type mice. In both wild-type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately 19% lower in bm/bm cells than in wild-type cells (P<0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild-type mice in exhibiting a lower optical density and slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in mast cells are operative in bm/bm cells.

The role of granules within viscous capture threads of orb-weaving spiders

Sticky viscous prey capture threads form the spiral elements of spider orb-webs and are responsible for retaining insects that strike a web. These threads are formed of regularly spaced aqueous droplets that surround a pair of supporting axial fibers. When a thread is flattened on a microscope slide a small, opaque granule can usually be seen within each droplet. These granules have been thought to be the glycoprotein glue that imparts thread adhesion. Both independent contrast and standard regressions showed that granule size is directly related to droplet volume and indicated that granule volume is about 15% of droplet volume. We attempted to find support for the hypothesized adhesive role of granules by establishing an association between the contact surface area and volume of these granules and the stickiness of the viscous threads of 16 species in the context of a six-variable model that describes thread stickiness. However, we found that granule size made either an insignificant or a small negative contribution to thread stickiness. Consequently, we hypothesize that granules serve to anchor larger, surrounding layers of transparent glycoprotein glue to the axial fibers of the thread, thereby equipping droplets to resist slippage on the axial fibers as these droplets generate adhesion, elongate under a load, and transfer force to the axial fibers.

Starch granule size distribution in wheat grain in relation to shading after anthesis

SUMMARYGranule size distribution of wheat starch is an important characteristic that may affect the functionality of wheat products. Light intensity is one of the main factors affecting grain yield and quality. Two high-yield winter wheat cultivars were grown under shade to evaluate the effect of low light intensity after anthesis on starch granule size distribution and starch components in wheat grains at maturity. Shading caused a marked drop in both grain yield and starch yield and led to a significant reduction in the proportion (both by volume and by surface area) of B-type starch granules (⩽9·9 μm), with an increase in those of A-type starch granules (&gt;9·9 μm). This would suggest that the production of B-type starch granules was more sensitive to shading than that of A-type starch granules. It was also found that the proportion by volume of A-type starch granules was significantly increased and that of B-type starch granules was significantly decreased by shading at different grain filling stages, especially at middle and late grain-filling stages. However, shading had little effect on the proportional number of B-type starch granules. The present results suggested that, under dim light conditions, the limited substrate for starch accumulation was mainly partitioned towards hypertrophy (larger granules) not hyperplasia (more) of starch granules.

Starch Granule Size Distribution in Grains at Different Positions on the Spike of Wheat (Triticum aestivum L.)

AbstractThe present study was carried out to characterize the effects of soil water status, cultivar and grain position on starch granule size distribution. The starch granule size distribution and protein and starch content were determined from three wheat cultivars with reference to the position of the grain on the spike. The results showed that the contents of A‐, B‐ and C‐type starch granules were affected by soil water, genotype and soil water×genotype interaction. Grain position was significant for A‐ and C‐type starch granules. Genotype×grain position and soil water×genotype×grain position interactions only affected C‐type starch granules. Both basal and distal grains on middle spikelets contained three types of starch granules: smaller C‐type granules with diameters &lt;2.0 μm, medium B‐type granules with diameters 2.0–9.8 μm and large A‐type granules with diameters &gt;9.8 μm at maturity. Both percent volume and percent surface area distribution of starch granules in basal grains showed the typical three populations, and those in distal grains exhibited a two‐peak curve. The volume and surface area percentage of C‐type granules and protein content in basal grains were higher than that in distal grains, but those of A, B‐type granules in basal grains were lower than that in distal grains. Compared with irrigation, the percent volume and surface area of B, C‐type starch granules and protein content in basal and distal grains were significantly increased, and those of A‐type were evidently decreased in rainfed condition.

Experimental study of the break-up of starch suspension droplets in step-up shear flow

The deformation and break-up of a droplet of suspension of swollen-in-water starch granules placed in an immiscible fluid, silicon oil, are investigated. The study was carried out on a physically modified waxy maize starch suspension with a theoretical granule volume fraction of 100%. Granules were swollen to their maximum; they were highly deformable. Measurements were carried out using a counter rotating shear cell. The starch suspension was shear thinning above a yield stress of about 90–100 Pa showing elasticity (first normal stress difference) above 300 Pa. The rheo-optical experiments were carried out by stepping up the stress from zero to a constant value and deformation of suspension droplets of various sizes was observed with time. Critical break-up capillary numbers Ca∗ were calculated and correlated with droplet-to-matrix viscosity ratio p. At low p values Ca∗ were found to be smaller or close to those determined for Newtonian fluids. No break-up was observed for viscosity ratios above 0.1, a limit that is roughly 40 times lower than that for the Newtonian fluids. This result was assumed to be due to the fact that internal stress in the droplet is lower than the mean one applied, because of inter-particle interactions and friction, thus shifting suspension from low to extremely high viscosity fluid if applied stress is close to the yield transition.