Large-sized Aggregates Research Articles

Amyloid Fiber Formation by Synthetic Peptides Derived from the Sequence of the Protein CsgA of Escherichia coli

We characterized the formation of amyloid fibers by two peptides derived from the CsgA sequence: R5 (133- 151) corresponding to the whole repeating unit R5 and a truncated form of this peptide called R5T (134-143). In the presence of either of the two peptides: an increase in the fluorescence intensity of Thioflavin T was observed; a shift of the absorbance of Congo red was measured; spontaneous formation of amyloid fibers was observed by polarized light as well asatomic force microscopy imaging. Large-size aggregates were observed with R5 while R5T formed fagots of individualized fibers. The infrared spectroscopy analysis revealed the presence of a greater number of intermolecular bonds for R5. In conclusion, a 10 aminoacids peptide derived from the R5 sequence was sufficient for the spontaneous formation of amyloid fibrils but not to form large-size aggregates of fibers.

“Green” Synthesized and Coated Nanosilver Alters the Membrane Permeability of Barrier (Intestinal, Brain Endothelial) Cells and Stimulates Oxidative Stress Pathways in Neurons

Nanosilver’s (nanoAg) use in medical applications and consumer products is increasing. Because of this, its “green” synthesis and surface modification with beneficial coatings are desirable. Given nanoAg’s potential exposure routes (e.g., dermal, intestinal, pulmonary), questions on its potential to move through these “port of entry” barriers and enter the body’s circulatory system remain unanswered. In view of nanoAg’s free radical activity and the brain’s sensitivity to oxidative stress damage, the possibility that nanoAg particles can move from the systemic circulation, transport through the blood-brain barrier (BBB), and pose a neurotoxic threat is also a legitimate concern. Because of these issues, this study addresses an initial event of barrier transport, that is, if “green” synthesized nanoAg, coated with green tea polyphenols (GT) or glutathione (GSH), can alter the permeability of human intestinal epithelial (Caco-2) or rat brain endothelial (RBEC4) barrier cells. Additionally, it asks if such “green” synthesized nanoAg modifies its toxicity to oxidative stress-sensitive cultured neurons (N27). Physicochemical (PC) characterization of conventionally synthesized nanoAg and “green” synthesized nanoAg-GT or nanoAg-GSH indicated that all samples aggregated (>500–2500 nm) when suspended in cell culture exposure media. NanoAg-GSH showed the least electronegative zeta potential and largest aggregate size in both Caco-2 and RBEC4 exposure media, relative to conventional nanoAg. Transcellular resistance measures indicated that within 15 min of exposure to 6.5 ppm, both conventional and nanoAg-GSH altered the permeability of intestinal Caco-2 monolayers, and all nanoAg treatments altered the permeability of RBEC4 brain endothelial cells. To examine if a differential toxicity existed in the response of oxidative stress-sensitive neurons, a noncytotoxic (1.0 ppm) concentration of each nanoAg material was exposed (18 h) to rat dopaminergic neurons (N27), transfected with a NFκβ reporter gene. Results indicated that all nanoAg samples significantly stimulated this oxidative stress pathway in the N27 neuron. Together, these data suggest that both conventional and “green” synthesized coated nanoAg alter the permeability of barrier cell membranes and activate oxidative stress pathways in target neurons, equivocally.

Mineralogy of the clay fraction of alfisols in two slope curvatures: IV - spatial correlation with physical properties

Although the influence of clay mineralogy on soil physical properties has been widely studied, spatial relationships between these features in Alfisols have rarely been examined. The purpose of this work was to relate the clay minerals and physical properties of an Alfisol of sandstone origin in two slope curvatures. The crystallographic properties such as mean crystallite size (MCS) and width at half height (WHH) of hematite, goethite, kaolinite and gibbsite; contents of hematite and goethite; aluminium substitution (AS) and specific surface area (SSA) of hematite and goethite; the goethite/(goethite+hematite) and kaolinite/(kaolinite+gibbsite) ratios; and the citrate/bicarbonate/dithionite extractable Fe (Fe d) were correlated with the soil physical properties through Pearson correlation coefficients and cross-semivariograms. The correlations found between aluminium substitution in goethite and the soil physical properties suggest that the degree of crystallinity of this mineral influences soil properties used as soil quality indicators. Thus, goethite with a high aluminium substitution resulted in large aggregate sizes and a high porosity, and also in a low bulk density and soil penetration resistance. The presence of highly crystalline gibbsite resulted in a high density and micropore content, as well as in smaller aggregates. Interpretation of the cross-semivariogram and classification of landscape compartments in terms of the spatial dependence pattern for the relief-dependent physical and mineralogical properties of the soil proved an effective supplementary method for assessing Pearson correlations between the soil physical and mineralogical properties.

Impact of Water Quality Parameters on the Clogging of Vertical-Flow Constructed Wetlands Treating Urban Wastewater

In theory, biological and physical clogging, induced as a result of potentially excessive formation of biomass from degradation of pollutants and retention of inert suspended fine particles, respectively, should result in a decrease of treatment performance. However, some wetlands are not prone to clogging in practice. The aim of this study was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand [COD] loading) variables on the treatment efficiency and clogging processes. Different vertical-flow constructed wetlands were constructed and operated from June 2011 until June 2012. Data from June 2011 (setting-up period) were not used. The filter with the highest COD loading performed the worst in terms of outflow COD concentration (120 mg/l) but best in terms of COD load reduction (61 %). The wetland with the largest aggregate size had the lowest mean nitrate-nitrogen outflow concentration of 1.2 mg/l. However, the results were similar regardless of aggregate size (10 versus 20 mm) and resting time (24 versus 48 h) for most water quality variables. However, different COD inflow concentrations (COD of 146 mg/l versus COD of 312 mg/l) had a significant (p < 0.05) impact on the treatment performance for COD, ammonia-nitrogen, ortho-phosphate-phosphorus and suspended solids (SS). Serious clogging phenomena impacting negatively on the treatment performance were not observed for any columns. However, a small aggregate diameter, a short contact time, a long resting time and a low COD inflow concentration were most beneficial in reducing SS accumulation within the wetland filters.

Ranibizumab frente a bevacizumab. Consideraciones farmacológicas

Bevacizumab is able to cross ocular barriers when administered through the intravitreal route and to generate plasma concentrations with an inhibitory effect on plasma vascular endothelial growth factor (VEGF). Consequently, systemic effects cannot be ruled out. The fact that bevacizumab is a full-length IgG explains this phenomenon through the participation of FcRn receptors, whose binding–like that of all IgGs–implies their internalization, transfer to the cell membrane, and externalization to the intracellular space and blood. This process occurs in all tissues with cells expressing this type of receptor, such as the eye. Moreover, because of the absence of a specific formulation for intravitreal administration, an intravenous formulation must be manipulated, generating large-sized aggregates, leading to potential problems of the solution's sterility and reducing the pharmacological effect. Ranibizumab is not a full-length IgG but is rather a variable IgG fraction with anti-VEGF activity. Because of the absence of a constant fraction in its structure, this drug cannot bind to the FcRn receptor and, as a result, cannot be transported to the blood. Consequently, its systemic bioavailability after intravitreal administration is nil, thus avoiding effects in parts of the body other than the eye. Moreover, the formulation is specifically prepared for intraocular administration, avoiding problems due to manipulation. The experience gained with these drugs allows the differences in their efficacy and tolerability to be transferred to daily practice

Platelet-associated tissue factor enhances platelet reactivity and thrombin generation in experimental studies in vitro

IntroductionThe thrombogenic potential of tissue factor (TF) associated to platelets is controversial. We have investigated the in vitro contribution of platelet-associated TF to thrombus formation. Materials and MethodsPlatelets suspensions were exposed to human TF-rich microvesicles (TF-MV) from placental or recombinant origin. Platelet-associated TF was quantified through coagulometric assays. Adhesive and cohesive properties of platelets containing TF were assessed in perfusion models using two thrombogenic surfaces: 1) type-I collagen, or 2) damaged vascular segments. Perfusion studies were performed with heparinized blood enriched with a 30% of washed platelets exposed to TF-MV vs. washed control platelets. Thrombin generation and thromboelastometric properties of clots were also assessed using a fluorometric assay and ROTEM analysis, respectively. Inhibitory strategies with an antibody to TF were performed in some cases. ResultsThe addition of 30% of platelets containing TF to blood perfusates resulted in a statistically significant increase in the platelet coverage (%CS) vs. non-exposed platelets on collagen surfaces (%CS: 19.7±0.6 and 23.9±0.7 respectively, vs.14.5±1.4; p<0.01) and on the vascular subendothelium (%CS: 54.0±1.5 and 47.2±6.8 respectively vs. 38.0±3.5, p<0.05), with a statistically significant increase in the size of large platelet aggregates (p<0.05) vs. control platelets. These effects on collagen surfaces were almost totally prevented by an antibody to TF. Platelet-associated TF significantly accelerated thrombin generation and clot formation (p<0.05), effects that were partially prevented by a neutralizing anti-TF. ConclusionsPlatelet-associated TF potentiated adhesive and aggregating properties in in vitro studies with flowing blood and accelerated thrombin generation and clot formation time under steady conditions.

Benign lymphoid aggregates in the bone marrow: distribution patterns of B and T lymphocytes

Benign lymphoid aggregates are seen in only a minority of bone marrow specimens, but their distinction from non-Hodgkin lymphoma, particularly B-cell lymphomas, can represent a diagnostic challenge. Although criteria have been proposed to help distinguish between benign and malignant aggregates, a detailed description of the distribution patterns of B and T lymphocytes within benign lymphoid aggregates has not been investigated. One hundred thirty-seven cases of bone marrow specimens containing benign aggregates were studied with a panel of immunostains. A subset of these cases was also examined for immunoglobulin gene rearrangements by polymerase chain reaction. The aggregates were categorized based on size, location (paratrabecular or random), presence of infiltrating edges, and distribution of lymphoid cell populations. In addition, we examined 40 cases of bone marrow biopsies with documented malignant lymphoid aggregates for comparison purposes. We report that the distribution of B and T lymphocytes within lymphoid aggregates may serve as a useful criterion to aid in the separation between benign and malignant aggregates. When aggregates exhibit a predominance of T cells, consist of a central core of T cells surrounded by a rim of B cells, or have a mixed distribution of B and T cells, they are more likely to be benign. On the other hand, an increased likelihood of malignancy occurs when aggregates exhibit a predominance of B cells or consist of a central core of B cells surrounded by a rim of T cells (excluding germinal center formation), and assessing other features worrisome of malignancy (large aggregate size, presence of infiltrative edges, cellular atypia, and paratrabecular location, among others) is warranted.

Investigation of asphalt concrete rutting mechanisms by X-ray computed tomography imaging and micromechanical finite element modeling

This paper systematically investigates the changes in asphalt concrete (AC) microstructure caused by full-scale accelerated pavement testing with a heavy vehicle simulator (HVS), using X-ray computed tomography images taken before and after HVS rutting tests. A viscoelastic micromechanical finite element modeling was also used to investigate effects of bitumen mastic and aggregate skeleton properties on shear resistance. The primary purpose was to determine the reasons behind the earlier failure of the rubberized gap graded AC mix used in the test compared to the polymer modified dense graded mix also included in the experiment. Shear related deformation appears to control the long term rutting performance of the test sections while densification was primarily an initial contributor at the very early stages of trafficking. A high concentration of aggregate interlock in the polymer modified mix, as a result of the dense gradation and larger aggregate sizes, appears to have resulted in greater dissipation of shear stresses and therefore greater shear resistance. The lack of this interlocking effect for the rubberized gap graded mix is proposed to have caused the earlier failure on HVS test sections.

Influence of monosodium glutamate additive on the morphology and permeability characteristics of polyamide dialysis membranes

Membranes were prepared with dope solutions of various concentrations of polyamide and monosodium glutamate (MSG) additive for dialysis applications. The results show that the membranes with higher MSG concentrations had higher water uptakes and porosities. The membranes were characterized with scanning electron microscopy (SEM) and atomic force microscopy techniques and evaluated in terms of the permeability of solutes, such as urea and creatinine. The cross-sectional structure of the membranes prepared without MSG additive or with a low MSG concentration were dense, and their surfaces consisted of large-sized nodule aggregates. The permeation of solutes was less through these membranes. When the amount of additive in the membrane solution was sufficient, macrovoids were seen in the SEM images, and the sizes of nodules were small, which caused an increase in the diffusive permeability of solutes. The surfaces of the membranes with higher MSG concentrations were found to be smooth; this could be useful for the dialysis process. The contact angles of these membranes were also lower; this indicated that this additive improved the hydrophilicity of the membranes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Three-dimensional discrete element modeling of asphalt concrete: Size effects of elements

This paper investigated effects of element sizes in three-dimensional discrete element modeling of asphalt concrete. Asphalt concrete was considered as a two-phase composite of mineral aggregates larger than 2.36mm and asphalt mastic. Even though asphalt mastic was a composite of fines, fine aggregates, asphalt, and air voids in the reality, it was considered as a homogenous media to interact with larger-size aggregates. A computer-generated discrete element model was employed to simulate the geometry of asphalt concrete. In the model, mineral aggregate particles larger than 2.36mm were simulated with randomly-created ellipsoids, while asphalt mastic occupied the remaining volume of the asphalt concrete. Each ellipsoid particle in the model was a cluster of discrete elements (balls) which were bonded with a built-in contact-bond model. With the computer-generated model, four digital samples were generated, whose element sizes (radius of balls) were 0.75mm, 0.65mm, 0.50mm, and 0.35mm. The mechanical interactions within the digital samples were simulated through four contact models, namely the linear contact stiffness model, the Burger’s model, the slip model, and the contact-bond model. The first two models were used to simulate force–displacement relations at contacts, while the last two models were employed to model the strength properties at the contacts. Creep compliance tests were simulated on the four digital samples to investigate size effects of discrete elements on creep stiffness. Through this research, it was found that (1) discrete element sizes gave insignificant effects on creep stiffness (the maximum difference among different samples were within 5%) and (2) discrete element sizes could impact time-steps, computational time, aggregate shape representation, etc.

Compression Behavior of Large-Sized Tire-Derived Aggregate for Embankment Application

Tire-derived aggregate (TDA) has been successfully used for highway embankment applications in the past. Previous applications mainly used small and medium tire sizes as TDA sources. There are no published test results in the literature regarding the compression behavior of TDA made solely from off-the-road tires (OTR). In this study, large-scale, one-dimensional compression tests are carried out to study the compression behavior of TDA from OTR as well as from passenger and light-truck tires (PLTT). Samples for the tests are prepared by varying the initial unit weights. The results show that there is a general trend of decreasing compressibility with increasing initial unit weight for both TDA sources. The compression test results are also used to compare compression behavior between the two TDA sources. It is found that the compression behavior of TDA from OTR and PLTT is more or less similar. Moreover, one-dimensional stress-strain regression equations were developed for TDA from OTR.

SIRT2 interferes with autophagy-mediated degradation of protein aggregates in neuronal cells under proteasome inhibition

Abnormal protein aggregates have been suggested as a common pathogenesis of many neurodegenerative diseases. Two well-known protein degradation pathways are responsible for protein homeostasis by balancing protein biosynthesis and degradative processes: the ubiquitin–proteasome system (UPS) and autophagy-lysosomal system. UPS serves as the primary route for degradation of short-lived proteins, but large-size protein aggregates cannot be degraded by UPS. Autophagy is a unique cellular process that facilitates degradation of bulky protein aggregates by lysosome. Recent studies have demonstrated that autophagy plays a crucial role in the pathogenesis of neurodegenerative diseases characterized by abnormal protein accumulation, suggesting that regulation of autophagy may be a valuable therapeutic strategy for the treatment of various neurodegenerative diseases. Sirtuin-2 (SIRT2) is a class III histone deacetylase that is expressed abundantly in aging brain tissue. Here, we report that SIRT2 increases protein accumulation in murine cholinergic SN56 cells and human neuroblastoma SH-SY5Y cells under proteasome inhibition. Overexpression of SIRT2 inhibits lysosome-mediated autophagic turnover by interfering with aggresome formation and also makes cells more vulnerable to accumulated protein-mediated cytotoxicity by MG132 and amyloid beta. Moreover, MG132-induced accumulation of ubiquitinated proteins and p62 as well as cytotoxicity are attenuated in siRNA-mediated SIRT2-silencing cells. Taken together, these results suggest that regulation of SIRT2 could be a good therapeutic target for a range of neurodegenerative diseases by regulating autophagic flux.

Study on the Morphology Feature of 1-Butyl-3-methylimidazolium Tetrafluoroborate Based Ionic Liquid Reverse Microemulsions

The micromorphology of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4)-in-cyclohexane and bmimBF4-in-triethylamine ionic liquid microemulsions was investigated by two-dimensional NMR and freeze-fracture transmission electron microscopy. The reverse micelles of Triton X-100/cyclohexane were destroyed by adding bmimBF4 and reverse microemulsions were induced to form by successively adding bmimBF4. However, no micelles appeared in triethylamine. But if adding bmimBF4 to a certain extent, a reverse microemulsion was also formed. The driving force of such aggregations could be attributed to the presence of different types of interactions between Triton X-100 and bmimBF4. A staggered arrangement of surfactant led to the irregular droplet structure and large aggregate size.

EFFECT OF COAGULANTS ON ANTIOXIDANT CAPACITY OF MILK PROTEIN CURDS AND THEIR TRYPTIC HYDROLYSATES

ABSTRACT This study investigated the influences of Ca lactate precipitation, lactic acid coagulation and renneting of proteins in skimmed milk on the physicochemical properties of milk protein powders. Scanning electron micrographs indicated that milk curd from Ca lactate precipitation had the densest network with the smallest protein particles compared with others. It also had the lowest antioxidant capacity: i.e., 0.27 and 0.05 µmol Trolox equivalent (TE)/mg protein, as measured by oxygen radical absorbance capacity–fluorescein (ORACFL) and Trolox equivalent antioxidant capacity (TEAC) assays, respectively (P < 0.05). Nevertheless, tryptic hydrolysis for 30 min increased the antioxidant capacity of all milk protein products to 0.85–1.11 and 1.17–1.19 µmol TE/mg protein in ORACFL and TEAC assays, respectively, regardless of the coagulants used (P ≥ 0.05). Although milk protein hydrolysate obtained from Ca lactate milk protein had the lowest ζ-potential, its antioxidant capacity remained unaffected by self-association of peptides into large-sized aggregates (P ≥ 0.05). PRACTICAL APPLICATIONS The results showed that Ca lactate milk protein powder could be used as a protein diet containing high Ca that would provide antioxidative peptides upon subsequent tryptic digestion. The study also suggested that milk protein hydrolysates with reasonable antioxidant capacity could be obtained from milk powder prepared from mixed proteins coagulated by Ca lactate, lactic acid or renneting and hydrolyzed by trypsin. This is important for developing countries with majority of the population suffering from lactose intolerance, i.e., having a milk surplus yet lacking the capability of fractionation of mixed milk proteins into individual proteins such as β-casein, κ-casein, β-lactoglobulin and α-lactalbumin.

Compositional analysis for an unbiased measure of soil aggregation

Soil aggregation is an index of soil structure measured by mean weight diameter (MWD) or scaling factors often interpreted as fragmentation fractal dimensions (Df). However, the MWD provides a biased estimate of soil aggregation due to spurious correlations among aggregate-size fractions and scale-dependency. The scale-invariant Df is based on weak assumptions to allow particle counts and sensitive to the selection of the fractal domain, and may frequently exceed a value of 3, implying that Df is a biased estimate of aggregation. Aggregation indices based on mass may be computed without bias using compositional analysis techniques. Our objective was to elaborate compositional indices of soil aggregation and to compare them to MWD and Df using a published dataset describing the effect of 7 cropping systems on aggregation. Six aggregate-size fractions were arranged into a sequence of D-1 balances of building blocks that portray the process of soil aggregation. Isometric log-ratios (ilrs) are scale-invariant and orthogonal log contrasts or balances that possess the Euclidean geometry necessary to compute a distance between any two aggregation states, known as the Aitchison distance (A(x,y)). Close correlations (r>0.98) were observed between MWD, Df, and the ilr when contrasting large and small aggregate sizes. Several unbiased embedded ilrs can characterize the heterogeneous nature of soil aggregates and be related to soil properties or functions. Soil bulk density and penetrater resistance were closely related to A(x,y) with reference to bare fallow. The A(x,y) is easy to implement as unbiased index of soil aggregation using standard sieving methods and may allow comparisons between studies.

Corn root growth and nutrient accumulation improved by five years of repeated cattle manure addition to eroded Chinese Mollisols

Zhou, K., Liu, X., Zhang, X., Sui, Y., Herbert, S. J. and Xia, Y. 2012. Corn root growth and nutrient accumulation improved by five years of repeated cattle manure addition to eroded Chinese Mollisols. Can. J. Soil Sci. 92: 521–527. The use of fertilizers with additional cattle manure application on eroded soil has been reported to improve cereal yields. Limited research exists on the long-term effect of cattle manure on root growth and nutrient uptake by corn (Zea mays L.) grown on eroded soils. A field experiment was established in Hailun city, Northeast China to determine the impact of long-term cattle manure addition on corn production in eroded Mollisols. There were five levels of simulated-erosion, which removed 0, 5, 10, 20, 30 cm of topsoil. Two soil amendments were: (1) chemical fertilizer at the rate normally used by farmers in the region and (2) chemical fertilizer plus 15 000 kg ha−1 (dry weight basis) of cattle manure. Root growth (length, surface area and dry weight) was assessed at the three-leaf stage. Nitrogen (N), phosphorus (P) and potassium (K) uptake and accumulation by corn were evaluated at the three-leaf stage and at harvest. Compared with chemical fertilizer alone, 5 yr of repeated cattle manure addition significantly increased root surface area by 18–35%, and root dry weight by 45–129% in soil with simulated-erosion. The improvement of root growth by manure application was mainly correlated with the changes in larger size aggregate. N content increased by 12–59%, P by 31–129%, and K by 297–494% in corn at the three-leaf stage, and the same trend was found at harvest. Long-term cattle manure addition increased corn yield by 7% in soils with 5 cm topsoil removal, and gave similar yields in soils with 10 and 20 cm topsoil removal as non-eroded plots receiving chemical fertilizer only. Our results suggest that the increased corn yield in manure-amended soils was related to greater N, P and K accumulation due to larger root surface area and biomass. Addition of cattle manure with chemical fertilizer would be a practical and effective approach to restore soil productivity and improve corn yields in eroded Chinese Mollisols.

Study on the Material Mechanical Performance of Large Scale Self-Compacting Rock-Filled Concrete

In order to study the influence of large size aggregate on self-compacting rock-filled concrete, the compactness between self-compacting concrete (SCC) and rocks, as well as the whole workability of self-compacting rock-filled concrete, the experimental test in the present paper was carried out on the 500-ton electro-hydraulic serve testing machine and the sizes of specimens are 450mm×450mm×450mm and 450mm×450mm×900mm. The results show that the exterior damage of self-compacting rock-filled concrete specimens are different from that of standard concrete specimens; the damage sections are flat and rocks are cut through in some areas, which shows mainly bond failure at interfaces between self-compacting concrete (SCC) and rocks. The compactness inside is well and the strength of self-compacting rock-filled concrete can almost reach that of SCC, which provides theoretical basis for the application of self-compacting rock-filled concrete.

Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

BackgroundMulticellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factors affecting aggregate size are modulated by adenosine and caffeine.ResultAdenosine and caffeine induced the formation of large and small aggregates respectively, in evolutionarily distinct slime molds known to use diverse chemoattractants for their aggregation. Due to its genetic tractability, we chose D. discoideum to further investigate the factors affecting aggregate size. The changes in aggregate size are caused by the effect of the compounds on several parameters such as cell number and size, cell-cell adhesion, cAMP signal relay and cell counting mechanisms. While some of the effects of these two compounds are opposite to each other, interestingly, both compounds increase the intracellular glucose level and strengthen cell-cell adhesion. These compounds also inhibit the synthesis of cAMP phosphodiesterase (PdsA), weakening the relay of extracellular cAMP signal. Adenosine as well as caffeine rescue mutants impaired in stream formation (pde4- and pdiA-) and colony size (smlA- and ctnA-) and restore their parental aggregate size.ConclusionAdenosine increased the cell division timings thereby making large number of cells available for aggregation and also it marginally increased the cell size contributing to large aggregate size. Reduced cell division rates and decreased cell size in the presence of caffeine makes the aggregates smaller than controls. Both the compounds altered the speed of the chemotactic amoebae causing a variation in aggregate size. Our data strongly suggests that cytosolic glucose and extracellular cAMP levels are the other major determinants regulating aggregate size and pattern. Importantly, the aggregation process is conserved among different lineages of cellular slime molds despite using unrelated signalling molecules for aggregation.

Rutting of Rubberized Gap-Graded and Polymer-Modified Dense-Graded Asphalt Overlays in Composite Pavements

The rutting performance of polymer-modified dense-graded and rubberized gap-graded asphalt mixes used in composite pavement was evaluated with full-scale accelerated pavement testing with the heavy vehicle simulator (HVS) and laboratory test results. The effect of asphalt layer thickness on measured surface deformation for both mix types was also investigated for recommendations for future design. In addition, the progression of the rutting failure mechanism for both mix types was evaluated with transverse cross sections measured with a laser profilometer at various HVS load repetitions. The polymer-modified dense-graded mix performed better than the rubberized gap-graded mix under both laboratory and HVS testing. The greater shear movement of the rubberized gap-graded mix under HVS loading caused larger humps, which consequently increased the maximum deformation and resulted in earlier failure. Larger aggregate size and denser gradation for the polymer-modified dense-graded mix resulted in more efficient dissipation of shear stresses and created greater permanent deformation resistance.

Effects of additional treatment of sarpogrelate to aspirin therapy on platelet aggregation and plasma plasminogen activator inhibitor activity in patients with stable effort angina

Introduction Serotonin is secreted from platelets at sites of endothelial injury, where it promotes thrombogenic reactions. Serotonin is reported to be associated with not only coronary artery disease but also cardiac events. Materials and Methods We studied 33 patients with stable effort angina (SEA) (11 patients with multivessel disease (MVD) and 22 patients with singlevessel disease (SVD)) and 25 patients with chest pain syndrome (CPS). Sarpogrelate was administered to 22 of 33 patients with SEA in addition to aspirin therapy, and platelet aggregation, plasma serotonin concentration, and plasma plasminogen activator inhibitor (PAI) activity were measured before and 1 week after administration. Results and Conclusions Serotonin level was higher in patients with MVD than in those with SVD (p < 0.05) and in those with CPS (p < 0.001). The formation of small-sized platelet aggregates was significantly higher in the high serotonin group than in the low serotonin group of SEA patients. The formation of large-sized platelet aggregates was significantly decreased by administration of sarpogrelate (P < 0.05). The formation of small- or medium-sized aggregates was not significantly decreased. Plasma PAI activity decreased significantly (P < 0.05) although the plasma serotonin concentration did not show significant change by administration of sarpogrelate. Plasma serotonin level is increased in relation to severity of coronary artery disease and plasma serotonin level is associated with increased platelet aggregation. Administration of sarpogrelate in addition to aspirin therapy reduces the increased platelet aggregation and PAI activity, and it may indicate that additional administration of sarpogrelate is useful for patients with SEA.