Effects Of Silvicultural Practice And Veneer Lay Upon Some Mechanical Properties Of Loblolly Pine Plywood

Treesearch

Todd F. Shupe; Chung Y. Hse; George A. Grozdits; Elvin T. Choong

1997-01-01

Loblolly pine three-ply plywood was manufactured from veneer obtained from silviculturally different stands. Panels from each site were assembled with four different veneer grade arrangements and tested in wet and dry conditions. Stiffness properties in both the wet and dry conditions and strength properties in the dry condition were all significantly affected by...

Effects of silviculture practice and veneer layup on some mechanical properties of loblolly pine plywood

Treesearch

Todd E. Shupe; Chung Y. Hse; George A. Grozdits; Elvin T. Choong

1997-01-01

Loblolly pine three-ply plywood was manufactured from veneer obtained from silviculturally different stands. Panels from each site were assembled with four different veneer grade arrangements and tested in wet and dry conditions. Stiffness properties in both the wet and dry conditions and strength properties in the dry condition were all significantly affected by...

Thermophysical properties of enzyme clarified Lime (Citrus aurantifolia L) juice at different moisture contents.

PubMed

Manjunatha, S S; Raju, P S; Bawa, A S

2014-11-01

Thermophysical properties of enzyme clarified lime (Citrus aurantifolia L.) juice were evaluated at different moisture contents ranging from 30.37 % to 89.30 % (wet basis) corresponding to a water activity range of 0.835 to 0.979. The thermophysical properties evaluated were density, Newtonian viscosity, thermal conductivity, specific heat and thermal diffusivity. The investigation showed that density and Newtonian viscosity of enzyme clarified lime juice decreased significantly (p < 0.05) with increase in moisture content and water activity, whereas thermal conductivity and specific heat increased significantly (p < 0.05) with increase in moisture content and water activity and the thermal diffusivity increased marginally. Empirical mathematical models were established relating to thermophysical properties of enzyme clarified lime juice with moisture content/water activity employing regression analysis by the method of least square approximation. Results indicated the existence of strong correlation between thermophysical properties and moisture content/water activity of enzyme clarified lime juice, a significant (p < 0.0001) negative correlation between physical and thermal properties was observed.

Elastic Properties of Chimpanzee Craniofacial Cortical Bone

PubMed Central

Gharpure, Poorva; Kontogiorgos, Elias D.; Opperman, Lynne A.; Ross, Callum F.; Strait, David S.; Smith, Amanda; Pryor, Leslie C.; Wang, Qian; Dechow, Paul C.

2017-01-01

Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke’s law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P<0.001). The elastic moduli demonstrated significant differences between sites, and a distinct pattern where E3 >E2 > E1. Shear moduli were significantly different among regions (P<0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. PMID:27870344

Profile and Functional Properties of Seed Proteins from Six Pea (Pisum sativum) Genotypes

PubMed Central

Barac, Miroljub; Cabrilo, Slavica; Pesic, Mirjana; Stanojevic, Sladjana; Zilic, Sladjana; Macej, Ognjen; Ristic, Nikola

2010-01-01

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin:legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products. PMID:21614186

Profile and functional properties of seed proteins from six pea (Pisum sativum) genotypes.

PubMed

Barac, Miroljub; Cabrilo, Slavica; Pesic, Mirjana; Stanojevic, Sladjana; Zilic, Sladjana; Macej, Ognjen; Ristic, Nikola

2010-01-01

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin:legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.

E. coli Surface Properties Differ between Stream Water and Sediment Environments.

PubMed

Liang, Xiao; Liao, Chunyu; Thompson, Michael L; Soupir, Michelle L; Jarboe, Laura R; Dixon, Philip M

2016-01-01

The importance of E. coli as an indicator organism in fresh water has led to numerous studies focusing on cell properties and transport behavior. However, previous studies have been unable to assess if differences in E. coli cell surface properties and genomic variation are associated with different environmental habitats. In this study, we investigated the variation in characteristics of E. coli obtained from stream water and stream bottom sediments. Cell properties were measured for 77 genomically different E. coli strains (44 strains isolated from sediments and 33 strains isolated from water) under common stream conditions in the Upper Midwestern United States: pH 8.0, ionic strength 10 mM and 22°C. Measured cell properties include hydrophobicity, zeta potential, net charge, total acidity, and extracellular polymeric substance (EPS) composition. Our results indicate that stream sediment E. coli had significantly greater hydrophobicity, greater EPS protein content and EPS sugar content, less negative net charge, and higher point of zero charge than stream water E. coli . A significant positive correlation was observed between hydrophobicity and EPS protein for stream sediment E. coli but not for stream water E. coli . Additionally, E. coli surviving in the same habitat tended to have significantly larger (GTG) 5 genome similarity. After accounting for the intrinsic impact from the genome, environmental habitat was determined to be a factor influencing some cell surface properties, such as hydrophobicity. The diversity of cell properties and its resulting impact on particle interactions should be considered for environmental fate and transport modeling of aquatic indicator organisms such as E. coli .

Cold/hot pad differentiating assay of property differences of Mahuang and Maxingshigan decoctions.

PubMed

Zhao, Yanling; Jia, Lei; Wang, Jiabo; Zou, Wenjun; Yang, Hongbo; Xiao, Xiaohe

2016-07-01

Chinese medicines with different cold/hot properties have various pharmacological actions on multiple organisms. The objective of this study was to explore the cold/hot property differences of traditional Chinese medicine formulas of Mahuang and Maxingshigan decoctions. A novel cold/hot pad differentiating assay method based on the Intelligent Animal Temperature Tropism Behavior monitoring system at 20 °C (cold pad) and 30 °C (hot pad) was introduced to investigate the variability of temperature tropism among the mice treated by 0.4 mL/20 g (drug volume/body weight) of Mahuang decoction and Maxingshigan decoction, respectively. Meanwhile, the oxygen consumption and activities of adenosine triphosphatase (ATPase) were measured to explore the energy metabolism mechanism. Results showed that the differences between cold/hot properties of Mahuang decoction and Maxingshigan decoction were significant (p < 0.05). Mahuang decoction produced significant synergic effect (a combination index of 1.60), while Maxingshigan decoction expressed significant antagonistic effect (a combination index of 0.35). The changes of energy metabolism including ATPase activity and oxygen consumption might be the possible factors to result in the differences. Those influences tended to be coherent with the definition of cold/hot properties of Chinese medicines based on traditional Chinese medicinal theory. The results indicated that the method based on cold/hot pad differentiating array could objectively and quantitatively represent the cold/hot properties of different compatibilities of traditional Chinese medicines in an ethological way according to the changes of animal's temperature tropism. These findings would provide some experimental basis and data references as well as a novel evaluation method for the study of the regularity of recipe composition.

An in-vitro evaluation of mechanical and esthetic properties of orthodontic sealants

PubMed Central

Premaraj, Thyagaseely Sheela; Rohani, Nima; Covey, David; Premaraj, Sundaralingam; Hua, Yi; Watanabe, Hidehiko

2014-01-01

Objective: To evaluate mechanical and esthetic Properties of two commercially available orthodontic sealants: Opal®Seal (OS) and L.E.D. Pro Seal (PS). Materials and Methods: Discs of each sealant were prepared to test the following properties: Micro hardness, wear resistance and color stability. Samples were randomly selected after the wear test for SEM imaging to analyze surface morphology. Results: OS was significantly harder than PS (P < 0.001). PS was significantly more wear resistant than OS (P < 0.05). PS showed a greater ∆E*ab (increased staining) when placed in wine or coffee showing a significant difference (P < 0.05). SEM showed particle size, shape and distribution were different for PS and OS reflecting the pattern seen on wear surfaces. Conclusion: Both orthodontic sealants are beneficial for protecting enamel. However with better wear properties PS was superior in resisting mechanical stresses. OS was more color stable. PMID:25512729

Influence of different emulsifiers on characteristics of eggless cake containing soy milk: Modeling of physical and sensory properties by mixture experimental design.

PubMed

Rahmati, Nazanin Fatemeh; Mazaheri Tehrani, Mostafa

2014-09-01

Emulsifiers of different structures and functionalities are important ingredients usually used in baking cakes with satisfactory properties. In this study, three emulsifiers including distilled glycerol mono stearate (DGMS), lecithin and sorbitan mono stearate (SMS) were used to bake seven eggless cakes containing soy milk and optimization was performed by using mixture experimental design to produce an eggless cake sample with optimized properties. Physical properties of cake batters (viscosity, specific gravity and stability), cake quality parameters (moisture loss, density, specific volume, volume index, contour, symmetry, color and texture) and sensory attributes of eggless cakes were analyzed to investigate functional potential of the emulsifiers and results were compared with those of control cake containing egg. Almost in all cases emulsifiers, compared to the control cake, changed properties of eggless cakes significantly. Regarding models of different response variables (except for some properties) and their high R(2) (99.51-100), it could be concluded that models obtained by mixture design were significantly fitted for the studied responses.

Isolation, characterization of wheat gluten and its regeneration properties.

PubMed

Kaushik, Ravinder; Kumar, Naveen; Sihag, Manvesh Kumar; Ray, Aradhita

2015-09-01

In order to assess the effectiveness of different drying methods on physicochemical and reconstitution properties of wheat gluten, four wheat cultivars were selected and milled. Gluten was extracted and its wet and dry gluten content and water holding capacity were estimated. The washed starch and other flour constituents were dried. Isolated gluten was dried using three treatments viz. oven drying, vacuum drying and freeze drying. Dried gluten of four wheat cultivars were characterized for its water and oil absorption properties and thermal properties. The dried gluten and washed and dried flour constituents were then reconstituted and this flour was checked for flour quality (SDS volume, texture analysis and falling number). Only reconstituted flour using freeze dried gluten showed no significant difference to control flour in SDS volume and dough strength. In Falling number all reconstituted flour samples showed significant difference to control flour.

Evaluation of the technological and sensory properties of durum wheat spaghetti enriched with different dietary fibres.

PubMed

Rakhesh, Nisha; Fellows, Christopher M; Sissons, Mike

2015-01-01

The incorporation of fibres, whether insoluble or soluble, in durum wheat pasta negatively impacts desirable end-use properties, especially if incorporated in significant amounts. Fibres can disrupt the starch-protein matrix of the dough during pasta preparation and can also often swell more readily with water than starch, competing with the starch for water during dough development. Similar degrees of substitution with different fibres gave markedly different impacts on firmness, stickiness, cooking loss and sensory attributes, suggesting that results obtained for one fibre cannot readily be generalized to other fibres. The in vitro starch digestibility of the pastas was significantly reduced when resistant starch, β-glucan-enriched flour, carboxymethyl cellulose or guar gum was incorporated but increased when pollard or inulin was added. In many instances, different sources of the same fibre gave dramatically different impacts on the properties of cooked durum wheat pasta. © 2014 Society of Chemical Industry.

General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

PubMed Central

Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B.; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M.; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W.; Wolters, Volkmar; Schrumpf, Marion

2012-01-01

Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types. PMID:22937029

The effects of multiple repairs on Inconel 718 weld mechanical properties

NASA Technical Reports Server (NTRS)

Russell, C. K.; Nunes, A. C., Jr.; Moore, D.

1991-01-01

Inconel 718 weldments were repaired 3, 6, 9, and 13 times using the gas tungsten arc welding process. The welded panels were machined into mechanical test specimens, postweld heat treated, and nondestructively tested. Tensile properties and high cycle fatigue life were evaluated and the results compared to unrepaired weld properties. Mechanical property data were analyzed using the statistical methods of difference in means for tensile properties and difference in log means and Weibull analysis for high cycle fatigue properties. Statistical analysis performed on the data did not show a significant decrease in tensile or high cycle fatigue properties due to the repeated repairs. Some degradation was observed in all properties, however, it was minimal.

Evaluation of Mechanical Properties and Marginal Fit of Crowns Fabricated Using Commercially Pure Titanium and FUS-Invest

PubMed Central

Wu, Jinshuang; Wang, Xianli; Xing, Helin; Guo, Tianwen; Dong, Chaofang

2017-01-01

This study investigated the mechanical properties and single crown accuracy of the tailor-made Fourth University Stomatology investment (FUS-invest) for casting titanium. Background. Current investment for casting titanium is not optimal for obtaining high-quality castings, and the commercially available titanium investment is costly. Methods. Titanium specimens were cast using the tailor-made FUS-invest. The mechanical properties were tested using a universal testing machine. Fractured castings were characterized by energy-dispersive spectroscopy. 19 titanium crowns were produced using FUS-invest and another 19 by Symbion. The accuracy of crowns was evaluated. Results. The mechanical properties of the titanium cast by FUS-invest were elastic modulus 125.6 ± 8.8 GPa, yield strength 567.5 ± 11.1 MPa, tensile strength 671.2 ± 15.6 MPa, and elongation 4.6 ± 0.2%. For marginal fit, no significant difference (P > 0.05) was found at four marker points of each group. For internal fit, no significant difference (P > 0.05) was found between two groups, whereas significant difference (P < 0.01) was found at different mark point of each group. Conclusions. The mechanical properties of titanium casted using FUS-invest fulfilled the ISO 9693 criteria. The marginal and internal fit of the titanium crowns using either the FUS-invest or Symbion were similar. PMID:28913355

Effect of dermal thickness, tissue composition, and body site on skin biomechanical properties.

PubMed

Smalls, Lola K; Randall Wickett, R; Visscher, Marty O

2006-02-01

Quantitative measurement of skin biomechanical properties has been used effectively in the investigation of physiological changes in tissue structure and function and to determine treatment efficacy. As the methods are applied to new questions, tissue characteristics that may influence the resultant biomechanical properties are important considerations in the research design. For certain applications, variables such as dermal thickness and subdermal tissue composition, as well as age and/or solar exposure, may influence the skin biomechanics. We determined the influence of dermal thickness, tissue composition, and age on the skin biomechanical properties at the shoulder, thigh, and calf among 30 healthy females. We compared two devices, the Biomechanical Tissue Characterization System and the Cutometer SEM 575 Skin Elasticity Meter , to determine the effect of tissue sampling size. Dermal thickness was measured with 20 MHz ultrasound (Dermascan C) and tissue composition was inferred from anthropomorphic data. Skin thickness was significantly correlated with stiffness, energy absorption, and U(r)/U(f) for the shoulder. Body mass index (BMI) was significantly correlated with stiffness (negative correlation), energy absorption (positive), and skin thickness (negative) for the shoulder. Significant differences across body sites were observed. The calf was significantly different from the thigh and shoulders for all parameters (P<0.05, one-way anova). The calf had significantly lower laxity, laxity%, elastic deformation, energy absorption, elasticity, elasticity %, U(r), U(f), and U(r)/U(f) and significantly higher stiffness compared with the thighs and shoulders. sites. The thigh and shoulder sites were significantly different for all parameters except U(r)/U(f), elasticity %, laxity%, and stiffness. The dominant and non-dominant sides were significantly different. The dominant side (right for 90% of the subjects) had increased stiffness and decreased energy absorption (tissue softness, compliance) compared with the left side. A significant (P< or =0.02) negative relationship with age was seen for all biomechanical measures except stiffness at the shoulder. For the thigh and calf sites, significant negative correlations with age were found for elasticity %, U(r), and U(r)/U(f). Age and skin thickness were not correlated in this population. Skin thickness and age influenced the energy absorption at the shoulder site. The biological elasticity at the calf site could be predicted by age and BMI. The biological activity at the thigh site could be predicted by skin thickness and BMI. Significant regional variations in biomechanical properties and dominant side effects were observed. The biomechanical properties were significantly influenced by age. Certain properties varied with dermal thickness and tissue composition. The parameters were well correlated between the two instruments. The Cutometer, with its smaller aperture, was found to be more sensitive to age relationships.

Properties of Cookies Made with Natural Wax-Vegetable Oil Organogels.

PubMed

Hwang, Hong-Sik; Singh, Mukti; Lee, Suyong

2016-05-01

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax-VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax-VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Effects of Biochar Amendment on Soil Properties and Soil Carbon Sequestration

NASA Astrophysics Data System (ADS)

Zhang, R.; Zhu, S.

2015-12-01

Biochar addition to soils potentially affects various soil properties and soil carbon sequestration, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties as well as soil carbon sequestration. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates and the amount of soil carbon storage.

Aging properties of Kodak type 101 emulsions

NASA Technical Reports Server (NTRS)

Dohne, B.; Feldman, U.; Neupert, W.

1984-01-01

Aging tests for several batches of Kodak type 101 emulsion show that storage conditions significantly influence how well the film will maintain its sensitometric properties, with sensitivity and density increasing to a maximum during this period. Any further aging may result in higher fog levels and sensitivity loss. It is noted that storage in an environment free of photographically active compounds allows film property optimization, and that film batches with different sensitivities age differently. Emulsions with maximum 1700-A sensitivity are 2.5 times faster than those at the low end of the sensitivity scale. These sensitive emulsions exhibit significantly accelerated changes in aging properties. Their use in space applications requires careful consideration of time and temperature profiles, encouraging the use of less sensitive emulsions when the controllability of these factors is limited.

Guar by-product improves carbohydrate tolerance in healthy human subjects.

PubMed

Track, N S; Lai, V W; Chiu, S S

1985-08-01

Guar gum possesses distinct hypoglycemic properties. The other fraction of the guar bean, guar by-product (GBP), was studied to determine if it possesses any hypoglycemic properties. When 25 g GBP or wheat bran were consumed with a carbohydrate test meal by 10 healthy subjects, at 15 and 30 min after the GBP test meal significantly lower normalized plasma glucose responses were measured. Postprandial plasma insulin responses were similar after both test meals. During the first 60 min postprandially, the mean integrated plasma glucose response area was significantly lower after the GBP test meal. These data indicate that GBP, like guar gum, possesses hypoglycemic properties; because of the different chemical characteristics of these 2 guar bean fractions, it seems that their hypoglycemic properties are due probably to different mechanisms.

Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments

USGS Publications Warehouse

Stoliker, Deborah L.; Kent, Douglas B.; Zachara, John M.

2011-01-01

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2-, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logKc) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logKc values. Using this approach, logKc values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (Kc uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.

Elastic Properties of Chimpanzee Craniofacial Cortical Bone.

PubMed

Gharpure, Poorva; Kontogiorgos, Elias D; Opperman, Lynne A; Ross, Callum F; Strait, David S; Smith, Amanda; Pryor, Leslie C; Wang, Qian; Dechow, Paul C

2016-12-01

Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P < 0.001). The elastic moduli demonstrated significant differences between sites, and a distinct pattern where E 3  > E 2  > E 1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Flow properties and chemical composition of carob (Ceratonia siliqua L.) flours as related to particle size and seed presence.

PubMed

Benković, Maja; Belščak-Cvitanović, Ana; Bauman, Ingrid; Komes, Draženka; Srečec, Siniša

2017-10-01

Due to abundance in carbohydrates, dietary fibres and bioactive compounds, as well as for its outspread and low prices, carob (Ceratonia siliqua L.) flour has a great potential of use as a functional ingredient. The aim of this study was to analyse this potential by physical and chemical properties assessment of different particle sizes of carob flour with and without seeds. The influence of seed presence on physical and chemical properties of flour was also investigated. Seed presence in carob flour led to higher cohesivity and cake strength. It also affected the extraction efficiency of polyphenols, which was confirmed by the ranking of samples according to their procyanidin and tannins contents. With regard to the carbohydrate content, significant differences (P<0.05) between the contents of fructose and glucose was established in samples differing by the presence of carob seeds. Spearman rank order correlations revealed a significant difference (P<0.05) between physical and chemical properties of carob flours. These findings confirm the importance of understanding physical and chemical properties of carob flours in order to use them efficiently as a functional food ingredient. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterising the biophysical properties of normal and hyperkeratotic foot skin.

PubMed

Hashmi, Farina; Nester, Christopher; Wright, Ciaran; Newton, Veronica; Lam, Sharon

2015-01-01

Plantar foot skin exhibits unique biophysical properties that are distinct from skin on other areas of the body. This paper characterises, using non-invasive methods, the biophysical properties of foot skin in healthy and pathological states including xerosis, heel fissures, calluses and corns. Ninety three people participated. Skin hydration, elasticity, collagen and elastin fibre organisation and surface texture was measured from plantar calluses, corns, fissured heel skin and xerotic heel skin. Previously published criteria were applied to classify the severity of each skin lesion and differences in the biophysical properties compared between each classification. Calluses, corns, xerotic heel skin and heel fissures had significantly lower levels of hydration; less elasticity and greater surface texture than unaffected skin sites (p < 0.01). Some evidence was found for a positive correlation between hydration and elasticity data (r ≤ 0.65) at hyperkeratotic sites. Significant differences in skin properties (with the exception of texture) were noted between different classifications of skin lesion. This study provides benchmark data for healthy and different severities of pathological foot skin. These data have applications ranging from monitoring the quality of foot skin, to measuring the efficacy of therapeutic interventions.

[Relationships between vegetation characteristics and soil properties at different restoration stages on slope land with purple soils in Hengyang of Hunan Province, South-central China].

PubMed

Yang, Ning; Zou, Dong-Sheng; Yang, Man-Yuan; Hu, Li-Zhen; Zou, Fang-Ping; Song, Guang-Tao; Lin, Zhong-Gui

2013-01-01

By using space series to replace time series, this paper studied the relationships between the vegetation characteristics and soil properties at different restoration stages on the slope land with purple soils in Hengyang of Hunnan Province South-central China. There existed obvious differences in the soil physical and chemical properties at different restoration stages. From grassplot, grass-shrub, shrub to shrub-arbor, the soil organic matter, total and available N, and moisture contents increased markedly, soil bulk density had an obvious decrease, soil total and available P contents changed little, and soil pH decreased gradually, but no significant differences were observed among different restoration stages. At different restoration stages, the biomass of plant community had effects on the quantity and composition of soil microbes. The quantities of soil bacteria and fungi had significant positive correlations with the aboveground biomass of plant community, but the quantity of soil actinomycetes had less correlation with plant community's aboveground biomass. At different restoration stages, the activities of soil urease, protease, alkaline phosphatase, invertase, cellulase, catalase, and polyphenol oxidase decreased with increasing soil layer, and had significant positive correlations with plant community's richness and aboveground biomass.

Ethnopharmacological studies of Tribulus terrestris (Linn). in relation to its aphrodisiac properties.

PubMed

Mathur, Manish; Sundaramoorthy, S

2012-01-01

Synergism and antagonism impact of different plant metabolites present in crude fruit extract of Tribulus terrestris 'the herbal Viagra' have been studied. Variability in plant composition, biomass and metabolites concentration in different modules was significantly contributed by spatial factor. However the edhaphic parameters also changes with both spatial and temporal factors significantly. Fruit is the officinal part and the fruit production significantly related with soil nitrogen (P<0.01), whereas the soil nitrogen and pH also influenced the alkaloid content in fruit (P<0.05). The linear relation between fruit protein and fruit alkaloid (P<0.01) also observed and the relationship in between different soil parameters were established. Bioassay work confirmed its aphrodisiac properties, and site III is suggested for maximum biomass and high concentration of different metabolites.

Mechanical properties of silk of the Australian golden orb weavers Nephila pilipes and Nephilaplumipes.

PubMed

Kerr, Genevieve G; Nahrung, Helen F; Wiegand, Aaron; Kristoffersen, Joanna; Killen, Peter; Brown, Cameron; Macdonald, Joanne

2018-02-22

Silks from orb-weaving spiders are exceptionally tough, producing a model polymer for biomimetic fibre development. The mechanical properties of naturally spun silk threads from two species of Australian orb-weavers, Nephila pilipes and Nephila plumipes , were examined here in relation to overall thread diameter, the size and number of fibres within threads, and spider size. N. pilipes , the larger of the two species, had significantly tougher silk with higher strain capacity than its smaller congener, producing threads with average toughness of 150 MJ m -3 , despite thread diameter, mean fibre diameter and number of fibres per thread not differing significantly between the two species. Within N. pilipes , smaller silk fibres were produced by larger spiders, yielding tougher threads. In contrast, while spider size was correlated with thread diameter in N. plumipes , there were no clear patterns relating to silk toughness, which suggests that the differences in properties between the silk of the two species arise through differing molecular structure. Our results support previous studies that found that the mechanical properties of silk differ between distantly related spider species, and extends on that work to show that the mechanical and physical properties of silk from more closely related species can also differ remarkably. © 2018. Published by The Company of Biologists Ltd.

Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

PubMed Central

López-Suevos, Francisco; Dickens, Sabine H.

2008-01-01

Objective Evaluate the effects of core structure and storage conditions on the mechanical properties of acid-resin modified composites and a control material by three-point bending and conversion measurements 15 min and 24 h after curing. Methods The monomers pyromellitic dimethacrylate (PMDM), biphenyldicarboxylic-acid dimethacrylate (BPDM), (isopropylidene-diphenoxy)bis(phthalic-acid) dimethacrylate (IPDM), oxydiphthalic-acid dimethacrylate (ODPDM), and Bis-GMA were mixed with triethyleneglycol dimethacrylate (TEGDMA) in a 40/60 molar ratio, and photo-activated. Composite bars (Barium-oxide-glass/resin = 3/1 mass ratio, (2 × 2 × 25) mm, n = 5) were light-cured for 1 min per side. Flexural strength (FS), elastic modulus (E), and work-of-fracture (WoF) were determined in three-point bending after 15 min (stored dry); and after 24 h under dry and wet storage conditions at 37 °C. Corresponding degrees of conversion (DC) were evaluated by Fourier transform infrared spectroscopy. Data was statistically analyzed (2-way analysis of variance, ANOVA, Holm-Sidak, p < 0.05). Results Post-curing significantly increased FS, E and DC in nearly all cases. WoF did not change, or even decreased with time. For all properties ANOVA found significant differences and interactions of time and material. Wet storage reduced the moduli and the other properties measured with the exception of FS and WoF of ODPDM; DC only decreased in BPDM and IPDM composites. Significance Differences in core structure resulted in significantly different physical properties of the composites studied with two phenyl rings connected by one ether linkage as in ODPDM having superior FS, WoF and DC especially after 24 h under wet conditions. As expected, post-curing significantly contributed to the final mechanical properties of the composites, while wet storage generally reduced the mechanical properties. PMID:17980422

Effects of metal- and fiber-reinforced composite root canal posts on flexural properties.

PubMed

Kim, Su-Hyeon; Oh, Tack-Oon; Kim, Ju-Young; Park, Chun-Woong; Baek, Seung-Ho; Park, Eun-Seok

2016-01-01

The aim of this study was to observe the effects of different test conditions on the flexural properties of root canal post. Metal- and fiber-reinforced composite root canal posts of various diameters were measured to determine flexural properties using a threepoint bending test at different conditions. In this study, the span length/post diameter ratio of root canal posts varied from 3.0 to 10.0. Multiple regression models for maximum load as a dependent variable were statistically significant. The models for flexural properties as dependent variables were statistically significant, but linear regression models could not be fitted to data sets. At a low span length/post diameter ratio, the flexural properties were distorted by occurrence of shear stress in short samples. It was impossible to obtain high span length/post diameter ratio with root canal posts. The addition of parameters or coefficients is necessary to appropriately represent the flexural properties of root canal posts.

Effects of three different preservation methods on the mechanical properties of human and bovine cortical bone.

PubMed

Unger, Stefan; Stefan, Unger; Blauth, Michael; Michael, Blauth; Schmoelz, Werner; Werner, Schmoelz

2010-12-01

In the development of new strategies for fracture fixation, new methods have to be tested biomechanically under in vitro conditions before clinical trials can be performed. The gold standard for laboratory evaluations is fresh-frozen specimen. As the availability of fresh-frozen specimens is limited and since their use bears infectious risks, specimens treated with various chemical embalming fluids are also used. These preservation methods may alter the mechanical properties of the specimens used. Therefore, the aims of the present study were to determine the effects of three different preservation methods (formalin fixation (FO), Thiel-fixation (TH), and alcohol-glycerine fixation (AG)) on the elastic and postyield mechanical properties of cortical bone and to compare these properties to those of fresh-frozen (FF) specimens. Cylindrical cortical specimens (diameter 3mm, length 60 mm) were obtained from human femurs (n=48) and bovine tibiae (n=40). Before specimen immersion in different fixation fluids, bone mineral density (BMD) as well as the initial Young's modulus was determined. The Young's modulus was determined in a nondestructive bending test, and measurements were repeated after 6 months of immersion in fixative solution. Subsequent to the nondestructive test, a destructive 3-point bending test was conducted to assess the postyield and fracture properties. The BMD as well as the initial Young's modulus showed no significant differences between the four test groups. After 6 months in fixative solution, the Young's modulus was significantly lowered in human Thiel specimens and only showed minor changes in formalin- and alcohol-glycerine-treated specimens. The plastic energy absorption of human and bovine specimens was altered significantly. Formalin as well as alcohol-glycerine fixation yielded a significant decrease in plastic energy absorption, whereas Thiel fixation significantly increased the plastic energy absorption. Because of the significantly altered plastic mechanical properties of cortical bone, the use fresh-frozen bone specimens is recommended in biomechanical studies investigating failure loads of orthopaedic implants. The use of embalmed specimens should be restricted to pilot tests. Copyright © 2010 Elsevier Inc. All rights reserved.

Effect of Dietary Fiber Enrichment and Different Cooking Methods on Quality of Chicken Nuggets.

PubMed

Pathera, Ashok K; Riar, C S; Yadav, Sanjay; Sharma, D P

2017-01-01

The effect of dietary fiber enrichment (wheat bran) and cooking methods (oven, steam and microwave) on functional and physico-chemical properties of raw nuggets formulation as well as nutritional, color and textural properties of chicken nuggets were analyzed in this study. Among different cooking methods used for nuggets preparation, steam cooked nuggets had significantly ( p <0.05) higher water holding capacity (56.65%), cooking yield (97.16%) and total dietary fiber content (4.32%) in comparison to oven and microwave cooked nuggets. The effect of cooking methods and wheat bran incorporation was also noticed on textural properties of the nuggets. Hardness, firmness and toughness values of oven and steam cooked nuggets were significantly ( p <0.05) higher than microwave cooked nuggets. Among nuggets prepared by different cooking methods, cohesiveness of microwave cooked nuggets was found to be significantly ( p <0.05) highest, whereas, oven cooked nuggets had significantly ( p <0.05) highest gumminess and chewiness values. Steam cooked nuggets were found to be better among all nuggets due to their higher cooking yield and dietary fiber content.

Effect of Dietary Fiber Enrichment and Different Cooking Methods on Quality of Chicken Nuggets

PubMed Central

Yadav, Sanjay; Sharma, D. P.

2017-01-01

The effect of dietary fiber enrichment (wheat bran) and cooking methods (oven, steam and microwave) on functional and physico-chemical properties of raw nuggets formulation as well as nutritional, color and textural properties of chicken nuggets were analyzed in this study. Among different cooking methods used for nuggets preparation, steam cooked nuggets had significantly (p<0.05) higher water holding capacity (56.65%), cooking yield (97.16%) and total dietary fiber content (4.32%) in comparison to oven and microwave cooked nuggets. The effect of cooking methods and wheat bran incorporation was also noticed on textural properties of the nuggets. Hardness, firmness and toughness values of oven and steam cooked nuggets were significantly (p<0.05) higher than microwave cooked nuggets. Among nuggets prepared by different cooking methods, cohesiveness of microwave cooked nuggets was found to be significantly (p<0.05) highest, whereas, oven cooked nuggets had significantly (p<0.05) highest gumminess and chewiness values. Steam cooked nuggets were found to be better among all nuggets due to their higher cooking yield and dietary fiber content. PMID:28747827

Densification and Electrical Properties of Zinc Oxide Varistors Microwave-Sintered Under Different Oxygen Partial Pressures

NASA Astrophysics Data System (ADS)

Lin, Cong; Wang, Bo; Xu, Zheng; Peng, Hu

2012-11-01

ZnO varistors were prepared by microwave sintering under different oxygen partial pressures. The temperature profile and the densification behavior in different atmospheres were investigated. It was found that the density of ZnO varistors during sintering was the key factor affecting the absorption of microwave energy. The electrical properties, including the nonlinear properties and capacitance-voltage ( C- V) characteristics, were also carefully studied. The results showed that the oxygen partial pressure has significant effects on the electrical properties of ZnO varistors by changing the concentration of defects through a series of reactions involving oxygen during sintering.

The Effect of Rheological Properties of Foods on Bolus Characteristics After Mastication

PubMed Central

Hwang, Junah; Bae, Jung Hyun; Kang, Si Hyun; Seo, Kyung Mook; Kim, Byong Ki; Lee, Sook Young

2012-01-01

Objective To evaluate the effects of physical properties of foods on the changes of viscosity and mass as well as the particle size distribution after mastication. Method Twenty subjects with no masticatory disorders were recruited. Six grams of four solid foods of different textures (banana, tofu, cooked-rice, cookie) were provided, and the viscosity and mass after 10, 20, and 30 cycles of mastication and just before swallowing were measured. The physical properties of foods, such as hardness, cohesiveness, and adhesiveness, were measured with a texture analyzer. Wet sieving and laser diffraction were used to determine the distribution of food particle size. Results When we measured the physical characteristics of foods, the cookie was the hardest food, and the banana exhibited marked adhesiveness. Tofu and cooked-rice exhibited a highly cohesive nature. As the number of mastication cycles increased, the masses of all foods were significantly increased (p<0.05), and the viscosity was significantly decreased in the case of banana, tofu, and cooked-rice (p<0.05). The mass and viscosity of all foods were significantly different between the foods after mastication (p<0.05). Analyzing the distribution of the particle size, that of the bolus was different between foods. However, the curves representing the particle size distribution for each food were superimposable for most subjects. Conclusion The viscosity and particle size distribution of the bolus were different between solid foods that have different physical properties. Based on this result, the mastication process and food bolus formation were affected by the physical properties of the food. PMID:23342309

Tensile strength of biological fibrin sealants: a comparative study.

PubMed

Lacaze, Laurence; Le Dem, Nicolas; Bubenheim, Michael; Tsilividis, Basile; Mezghani, Julien; Schwartz, Lilian; Francois, Arnaud; Ertaud, Jean Yves; Bagot d'Arc, Maurice; Scotté, Michel

2012-08-01

Fibrin sealants are commonly used in liver surgery, although their effectiveness in routine clinical practice remains controversial. Individual sealant characteristics are based on hemostatic effects and adhesion properties that can be experimentally measured using the 'rat skin test' or the 'pig skin test'. This study used a more relevant and realistic experimental canine model to compare the differences in the adhesive properties of four fibrin sealants in hepatectomy: Tisseel/Tissucol, Tachosil, Quixil, and Beriplast. A partial hepatectomy was performed in beagle dogs under general anesthesia to obtain liver cross-sections. Fibrin sealants were allocated to dog livers using a Youden square design. The tensile strength measurement was performed using a traction system to measure the rupture stress point of a small wooden cylinder bonded to the liver cross-section. Significantly greater adhesion properties were observed with Tisseel/Tissucol compared with Quixil or Beriplast (P = 0.002 and 0.001, respectively). Similarly, Tachosil demonstrated significantly greater adhesive properties compared with Beriplast (P = 0.009) or Quixil (P = 0.014). No significant differences were observed between Tisseel/Tissucol and Tachosil or between Beriplast and Quixil. The results of this comparative study demonstrate that different fibrin sealants exhibit different adhesive properties. Tisseel/Tissucol and Tachosil provided greatest adhesion to liver cross-section in our canine model of hepatectomy. These results may enable the optimal choice of fibrin sealants for this procedure in clinical practice. Copyright © 2012 Elsevier Inc. All rights reserved.

A quantitative comparison of Soil Development in four climatic regimes

USGS Publications Warehouse

Harden, J.W.; Taylor, E.M.

1983-01-01

A new quantitative Soil Development Index based on field data has been applied to chronosequences formed under different climatic regimes. The four soil chronosequences, developed primarily on sandy deposits, have some numeric age control and are located in xeric-inland (Merced, Calif.), xeric-coastal (Ventura, Calif.), aridic (Las Cruces, N. Mex.), and udic (Susquehanna Valley, Pa.) soil-moisture regimes. To quantify field properties, points are assigned for developmental increases in soil properties in comparison to the parent material. Currently ten soil-field properties are quantified and normalized for each horizon in a given chronosequence, including two new properties for carbonate-rich soils in addition to the eight properties previously defined. When individual properties or the combined indexes are plotted as a function of numeric age, rates of soil development can be compared in different climates. The results demonstrate that (1) the Soil Development Index can be applied to very different soil types, (2) many field properties develop systematically in different climatic regimes, (3) certain properties appear to have similar rates of development in different climates, and (4) the Profile Index that combines different field properties increases significantly with age and appears to develop at similar rates in different climates. The Soil Development Index can serve as a preliminary guide to soil age where other age control is lacking and can be used to correlate deposits of different geographical and climatic regions. ?? 1983.

Assessment the effect of homogenized soil on soil hydraulic properties and soil water transport

NASA Astrophysics Data System (ADS)

Mohawesh, O.; Janssen, M.; Maaitah, O.; Lennartz, B.

2017-09-01

Soil hydraulic properties play a crucial role in simulating water flow and contaminant transport. Soil hydraulic properties are commonly measured using homogenized soil samples. However, soil structure has a significant effect on the soil ability to retain and to conduct water, particularly in aggregated soils. In order to determine the effect of soil homogenization on soil hydraulic properties and soil water transport, undisturbed soil samples were carefully collected. Five different soil structures were identified: Angular-blocky, Crumble, Angular-blocky (different soil texture), Granular, and subangular-blocky. The soil hydraulic properties were determined for undisturbed and homogenized soil samples for each soil structure. The soil hydraulic properties were used to model soil water transport using HYDRUS-1D.The homogenized soil samples showed a significant increase in wide pores (wCP) and a decrease in narrow pores (nCP). The wCP increased by 95.6, 141.2, 391.6, 3.9, 261.3%, and nCP decreased by 69.5, 10.5, 33.8, 72.7, and 39.3% for homogenized soil samples compared to undisturbed soil samples. The soil water retention curves exhibited a significant decrease in water holding capacity for homogenized soil samples compared with the undisturbed soil samples. The homogenized soil samples showed also a decrease in soil hydraulic conductivity. The simulated results showed that water movement and distribution were affected by soil homogenizing. Moreover, soil homogenizing affected soil hydraulic properties and soil water transport. However, field studies are being needed to find the effect of these differences on water, chemical, and pollutant transport under several scenarios.

Topological Organization of Functional Brain Networks in Healthy Children: Differences in Relation to Age, Sex, and Intelligence

PubMed Central

Wu, Kai; Taki, Yasuyuki; Sato, Kazunori; Hashizume, Hiroshi; Sassa, Yuko; Takeuchi, Hikaru; Thyreau, Benjamin; He, Yong; Evans, Alan C.; Li, Xiaobo; Kawashima, Ryuta; Fukuda, Hiroshi

2013-01-01

Recent studies have demonstrated developmental changes of functional brain networks derived from functional connectivity using graph theoretical analysis, which has been rapidly translated to studies of brain network organization. However, little is known about sex- and IQ-related differences in the topological organization of functional brain networks during development. In this study, resting-state fMRI (rs-fMRI) was used to map the functional brain networks in 51 healthy children. We then investigated the effects of age, sex, and IQ on economic small-world properties and regional nodal properties of the functional brain networks. At a global level of whole networks, we found significant age-related increases in the small-worldness and local efficiency, significant higher values of the global efficiency in boys compared with girls, and no significant IQ-related difference. Age-related increases in the regional nodal properties were found predominately in the frontal brain regions, whereas the parietal, temporal, and occipital brain regions showed age-related decreases. Significant sex-related differences in the regional nodal properties were found in various brain regions, primarily related to the default mode, language, and vision systems. Positive correlations between IQ and the regional nodal properties were found in several brain regions related to the attention system, whereas negative correlations were found in various brain regions primarily involved in the default mode, emotion, and language systems. Together, our findings of the network topology of the functional brain networks in healthy children and its relationship with age, sex, and IQ bring new insights into the understanding of brain maturation and cognitive development during childhood and adolescence. PMID:23390528

Topological organization of functional brain networks in healthy children: differences in relation to age, sex, and intelligence.

PubMed

Wu, Kai; Taki, Yasuyuki; Sato, Kazunori; Hashizume, Hiroshi; Sassa, Yuko; Takeuchi, Hikaru; Thyreau, Benjamin; He, Yong; Evans, Alan C; Li, Xiaobo; Kawashima, Ryuta; Fukuda, Hiroshi

2013-01-01

Recent studies have demonstrated developmental changes of functional brain networks derived from functional connectivity using graph theoretical analysis, which has been rapidly translated to studies of brain network organization. However, little is known about sex- and IQ-related differences in the topological organization of functional brain networks during development. In this study, resting-state fMRI (rs-fMRI) was used to map the functional brain networks in 51 healthy children. We then investigated the effects of age, sex, and IQ on economic small-world properties and regional nodal properties of the functional brain networks. At a global level of whole networks, we found significant age-related increases in the small-worldness and local efficiency, significant higher values of the global efficiency in boys compared with girls, and no significant IQ-related difference. Age-related increases in the regional nodal properties were found predominately in the frontal brain regions, whereas the parietal, temporal, and occipital brain regions showed age-related decreases. Significant sex-related differences in the regional nodal properties were found in various brain regions, primarily related to the default mode, language, and vision systems. Positive correlations between IQ and the regional nodal properties were found in several brain regions related to the attention system, whereas negative correlations were found in various brain regions primarily involved in the default mode, emotion, and language systems. Together, our findings of the network topology of the functional brain networks in healthy children and its relationship with age, sex, and IQ bring new insights into the understanding of brain maturation and cognitive development during childhood and adolescence.

Swirling cavitation improves the emulsifying properties of commercial soy protein isolate.

PubMed

Yang, Feng; Liu, Xue; Ren, Xian'e; Huang, Yongchun; Huang, Chengdu; Zhang, Kunming

2018-04-01

Since emulsifying properties are important functional properties of soy protein, many physical, chemical, and enzymatic methods have been applied to treat soy protein to improve emulsifying properties. In this study, we investigated the effects of swirling cavitation at different pressures and for different times on emulsifying and physicochemical properties of soy protein isolate (SPI). The SPI treated with swirling cavitation showed a significant decrease in particle size and increase in solubility. Emulsions formed from treated SPI had higher emulsifying activity and emulsifying stability indexes, smaller oil droplet sizes, lower flocculation indexes, higher adsorbed proteins, lower interfacial protein concentrations, and lower creaming indexes than those formed from untreated SPI, indicating that swirling cavitation improved the emulsifying properties of the SPI. Furthermore, swirling cavitation treatment significantly enhanced the surface hydrophobicity, altered the disulfide bond and exposed sulfhydryl group contents of the SPI. The secondary structure of the SPI was also influenced by swirling cavitation, with an increase in β-sheet content and a decrease in α-helix, β-turn, and random coil contents. In addition, several significant correlations between physicochemical and emulsifying properties were revealed by Pearson correlation analysis, suggesting that the physicochemical changes observed in treated SPI, including the decreased particle size, increased solubility and surface hydrophobicity, and enhanced β-sheet formation, may explain the improved emulsifying properties of the isolate. Thus, our findings implied that swirling cavitation treatment may be an effective technique to improve the emulsifying properties of SPI. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth-dependent effects of dietary protein concentration and quality on the biomechanical properties of the diaphyseal rat femur.

PubMed

Alippi, Rosa M; Picasso, Emilio; Huygens, Patricia; Bozzini, Carlos E; Bozzini, Clarisa

2012-01-01

This study compares the effects of feeding growing rats with increasing concentrations of casein (C) and wheat gluten (G), proteins that show different biological qualities, on the morphometrical and biomechanical properties of the femoral diaphysis. Female rats were fed with one of ten diets containing different concentrations (5-30%) of C and G between the 30th and 90th days of life (Control=C-20%). Biomechanical structural properties of the right femur middiaphysis were estimated using a 3-point bending mechanical test with calculation of some indicators of bone material properties. Body weight and length were affected by treatments, values being highest in rats fed the C-20% diet. G diets affected negatively both parameters. Changes in cross-sectional geometry (mid-diaphyseal cross-sectional and cortical areas, femoral volume, and rectangular moment of inertia) were positively related to the C content of the diet, while they were severely and negatively affected by G diets. Similar behaviors were observed in the bone structural properties (fracture load, yielding load, diaphyseal stiffness and elastic energy absorption). When values of strength and stiffness were normalized for body weight, the differences disappeared. The bone material quality indicators (elastic modulus, yielding stress, elastic energy absorption/volume) did not differ significantly among all studied groups. Femoral calcium concentration in ashes was not significantly different among groups. The clear differences in strength and stiffness of bone beams induced by dietary protein concentration and quality seemed to be the result of an induced subnormal gain in bone structural properties as a consequence of a correlative subnormal gain in bone growth and mass, yet not in bone material properties. Copyright © 2011 SEEN. Published by Elsevier Espana. All rights reserved.

Effect of Resin-modified Glass Ionomer Cement Dispensing/Mixing Methods on Mechanical Properties.

PubMed

Sulaiman, T A; Abdulmajeed, A A; Altitinchi, A; Ahmed, S N; Donovan, T E

2018-03-23

Resin-modified glass ionomer cements (RMGIs) are often used for luting indirect restorations. Hand-mixing traditional cements demands significant time and may be technique sensitive. Efforts have been made by manufacturers to introduce the same cement using different dispensing/mixing methods. It is not known what effects these changes may have on the mechanical properties of the dental cement. The purpose of this study was to evaluate the mechanical properties (diametral tensile strength [DTS], compressive strength [CS], and fracture toughness [FT]) of RMGIs with different dispensing/mixing systems. The RMGI specimens (n=14)-RelyX Luting (hand mix), RelyX Luting Plus (clicker-hand mix), RelyX Luting Plus (automix) (3M ESPE), GC Fuji PLUS (capsule-automix), and GC FujiCEM 2 (automix) (GC)-were prepared for each mechanical test and examined after thermocycling (n=7/subgroup) for 20,000 cycles to the following: DTS, CS (ISO 9917-1) and FT (ISO standard 6872; Single-edge V-notched beam method). Specimens were mounted and loaded with a universal testing machine until failure occurred. Two-/one-way analysis of variance followed by Tukey honestly significantly different post hoc test was used to analyze data for statistical significance ( p<0.05). The interaction effect of both dispensing/mixing method and thermocycling was significant only for the CS test of the GC group ( p<0.05). The different dispensing/mixing methods had no effect on the DTS of the tested cements. The CS of GC Fuji PLUS was significantly higher than that of the automix version ( p<0.05). The FT decreased significantly when switching from RelyX (hand mix) to RelyX Luting Plus (clicker-hand mix) and to RelyX Luting Plus (automix) ( p<0.05). Except in the case of the DTS of the GC group and the CS of GC Fuji PLUS, thermocycling had a significant effect reducing the mechanical properties of the RMGI cements ( p<0.05). Introducing alternative dispensing/mixing methods for mixing RMGIs to reduce time and technique sensitivity may affect mechanical properties and is brand dependent.

Genome Regions Associated with Functional Performance of Soybean Stem Fibers in Polypropylene Thermoplastic Composites

PubMed Central

Reinprecht, Yarmilla; Arif, Muhammad; Simon, Leonardo C.; Pauls, K. Peter

2015-01-01

Plant fibers can be used to produce composite materials for automobile parts, thus reducing plastic used in their manufacture, overall vehicle weight and fuel consumption when they replace mineral fillers and glass fibers. Soybean stem residues are, potentially, significant sources of inexpensive, renewable and biodegradable natural fibers, but are not curretly used for biocomposite production due to the functional properties of their fibers in composites being unknown. The current study was initiated to investigate the effects of plant genotype on the performance characteristics of soybean stem fibers when incorporated into a polypropylene (PP) matrix using a selective phenotyping approach. Fibers from 50 lines of a recombinant inbred line population (169 RILs) grown in different environments were incorporated into PP at 20% (wt/wt) by extrusion. Test samples were injection molded and characterized for their mechanical properties. The performance of stem fibers in the composites was significantly affected by genotype and environment. Fibers from different genotypes had significantly different chemical compositions, thus composites prepared with these fibers displayed different physical properties. This study demonstrates that thermoplastic composites with soybean stem-derived fibers have mechanical properties that are equivalent or better than wheat straw fiber composites currently being used for manufacturing interior automotive parts. The addition of soybean stem residues improved flexural, tensile and impact properties of the composites. Furthermore, by linkage and in silico mapping we identified genomic regions to which quantitative trait loci (QTL) for compositional and functional properties of soybean stem fibers in thermoplastic composites, as well as genes for cell wall synthesis, were co-localized. These results may lead to the development of high value uses for soybean stem residue. PMID:26167917

Multi-planar bending properties of lumbar intervertebral joints following cyclic bending.

PubMed

Chow, Daniel H K; Luk, Keith D K; Holmes, Andrew D; Li, Xing-Fei; Tam, Steven C W

2004-02-01

To assess the changes in the multi-planar bending properties of intervertebral joints following cyclic bending along different directions. An in vitro biomechanical study using porcine lumbar motion segments. Repeated bending has been suggested as part of the etiology of gradual prolapse of the intervertebral disc, but the multi-planar changes in bending properties following cyclic loading have not been examined in detail. Porcine lumbar motion segments were subject to 1500 cycles of bending along directions of 0 degrees (flexion), 30 degrees, 60 degrees, or 90 degrees (right lateral bending). The multi-planar bending moments and hysteresis energies were recorded before loading and after various cycle numbers. Repeated bending at 30 degrees and 60 degrees resulted in greater decreases in mean bending moment and hysteresis energy than bending at 0 degrees or 90 degrees. No significant differences were seen between loading groups for the change in bending moment along the anterior testing directions, but significant differences were observed in the posterior and lateral testing directions, with bending at 30 degrees causing a significantly greater decrease in bending moment in the postero-lateral directions. The change in mechanical properties of porcine intervertebral joints due to cyclic bending depend on the direction of loading and the direction in which the properties are measured. Loading at 30 degrees provokes the most marked changes in bending moment and hysteresis energy.

Effect of Different Cooling Regimes on the Mechanical Properties of Cementitious Composites Subjected to High Temperatures

PubMed Central

Yu, Jiangtao; Weng, Wenfang; Yu, Kequan

2014-01-01

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of engineered cementitious composite (ECC) subjected to high temperature up to 800°C was discussed in this paper. The ECC specimens are exposed to 100, 200, 400, 600, and 800°C with the unheated specimens for reference. Different cooling regimens had a significant influence on the mechanical properties of postfire ECC specimens. The microstructural characterization was examined before and after exposure to fire deterioration by using scanning electron microscopy (SEM). Results from the microtest well explained the mechanical properties variation of postfire specimens. PMID:25161392

Why the dish makes a difference: quantitative comparison of polystyrene culture surfaces.

PubMed

Zeiger, Adam S; Hinton, Benjamin; Van Vliet, Krystyn J

2013-07-01

There is wide anecdotal recognition that biological cell viability and behavior can vary significantly as a function of the source of commercial tissue culture polystyrene (TCPS) culture vessels to which those cells adhere. However, this marked material dependency is typically resolved by selecting and then consistently using the same manufacturer's product - following protocol - rather than by investigating the material properties that may be responsible for such experimental variation. Here, we quantified several physical properties of TCPS surfaces obtained from a wide range of commercial sources and processing steps, through the use of atomic force microscopy (AFM)-based imaging and analysis, goniometry and protein adsorption quantification. We identify qualitative differences in surface features, as well as quantitative differences in surface roughness and wettability that cannot be attributed solely to differences in surface chemistry. We also find significant differences in cell morphology and proliferation among cells cultured on different TCPS surfaces, and resolve a correlation between nanoscale surface roughness and cell proliferation rate for both cell types considered. Interestingly, AFM images of living adherent cells on these nanotextured surfaces demonstrate direct interactions between cellular protrusions and topographically distinct features. These results illustrate and quantify the significant differences in material surface properties among these ubiquitous materials, allowing us to better understand why the dish can make a difference in biological experiments. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Field Management of Hot Mix Asphalt Volumetric Properties

DOT National Transportation Integrated Search

1995-12-01

The Federal Highway Administration (FHWA) Demonstration Project No. 74 has clearly shown that significant differences exist between the volumetric properties of the laboratory designed and plant produced hot mix asphalt (HMA) mixes. The volumetric pr...

Dielectric Spectroscopy Study of ZnSe Grown by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Kokan, J.; Gerhardt, R.; Su, Ching-Hua

1997-01-01

The dielectric properties of ZnSe samples grown by physical vapor transport were measured as a function of frequency. Differences can be seen in the dielectric properties of samples grown under different conditions. The spectra of heat treated samples were also acquired and were found to exhibit significant deviations from those of the as grown crystals.

"Nonspecific" cholinesterase and acetylcholinesterase in rat tissues: molecular forms, structural and catalytic properties, and significance of the two enzyme systems.

PubMed Central

Vigny, M; Gisiger, V; Massoulié, J

1978-01-01

"Nonspecific" cholinesterase (acylcholine acylhydrolase; EC 3.1.1.8) from various rat tissues has been found to exist in several stable molecular forms that appear as exact counterparts of molecular forms of acetylcholinesterase (acetylcholine hydrolase; EC 3.1.1.7). The sedimentation pattern of cholinesterase was similar to that of acetylcholinesterase with a small but significant shift between the sedimentation coefficients of the corresponding forms. Extraction yields in different media also demonstrated a close parallelism between the two enzyme systems. Other properties, such as thermal stability and catalytic characteristics, indicated both differences and similarities. In spite of the structural resemblance implied by their physicochemical properties, cholinesterase did not crossreact with antibodies against acetylcholinesterase. The nature of the relationships revealed by these studies and their bearing on the physiological significance of cholinesterases are discussed. PMID:78492

Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

NASA Technical Reports Server (NTRS)

Steffes, Paul G.

1987-01-01

Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and Earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorping properties of potential constituents is available. The use of theoretically derived microwave absorption properties for such atmospheric constituents, or laboratory measurements of such properties under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. Laboratory measurement of the microwave properties of atmospheric gases under simulated conditions for the outer planets were conducted. Results of these measurements are discussed.

Comparison of isorhamnetin absorption properties in total flavones of Hippophae rhamnoides L. with its pure form in a Caco-2 cell model mediated by multidrug resistance-associated protein.

PubMed

Xie, Yan; Duan, Jingze; Fu, Qingxue; Xia, Mengxin; Zhang, Lei; Li, Guowen; Wu, Tao; Ji, Guang

2015-06-20

Total flavones of Hippophae rhamnoides L. (TFH) are extracted from the widely distributed thorny bush Sea buckthorn (Hippophae rhamnoides L.). Isorhamnetin (IS) is one of the representative ingredients in TFH. In this study, the absorption properties of IS in TFH and its pure form were compared through transepithelial transport and cellular uptake experiments in a Caco-2 cell model. Our results show that the absorption properties of IS in TFH and its pure form were remarkably different: (1) Both PappAB and PappBA of IS in TFH were dramatically increased compared with those of IS pure form; consequently, its Pratio was 2.3-fold higher than that of IS; (2) Both the accumulation and efflux of IS in TFH were significantly enhanced compared with the single compound. One likely reason for these differences is that the multiple components in TFH significantly down regulated the mRNA expression level of MRP2, which lead to a decrease in the protein level of MRP2, based on western blotting and RT-PCR assays. This study highlights the significant differences in the absorption properties of flavonoid components in different forms and the potential multi-component interactions in TFH. Copyright © 2015 Elsevier B.V. All rights reserved.

Low thermal dependence of the contractile properties of a wing muscle in the bat Carollia perspicillata.

PubMed

Rummel, Andrea D; Swartz, Sharon M; Marsh, Richard L

2018-05-29

Temperature affects contractile rate properties in muscle, which may affect locomotor performance. Endotherms are known to maintain high core body temperatures, but temperatures in the periphery of the body can fluctuate. Such a phenomenon occurs in bats, whose wing musculature is relatively poorly insulated, resulting in substantially depressed temperatures in the distal wing. We examined a wing muscle in the small-bodied tropical bat Carollia perspicillata and a hindlimb muscle in the laboratory mouse at 5°C intervals from 22 to 42°C to determine the thermal dependence of the contractile properties of both muscles. We found that the bat ECRL had low thermal dependence from near body temperature to 10°C lower, with Q 10 values of less than 1.5 for relaxation from contraction and shortening velocities in that interval, and with no significant difference in some rate properties in the interval between 32 and 37°C. In contrast, for all temperature intervals below 37°C, Q 10 values for the mouse EDL were 1.5 or higher, and rate properties differed significantly across successive temperature intervals from 37 to 22°C. An ANCOVA analysis found that the thermal dependencies of all measured isometric and isotonic rate processes were significantly different between the bat and mouse muscles. The relatively low thermal dependence of the bat muscle likely represents a downward shift of its optimal temperature and may be functionally significant in light of the variable operating temperatures of bat wing muscles. © 2018. Published by The Company of Biologists Ltd.

Effect of hydroxypropylcellulose and Tween 80 on physicochemical properties and bioavailability of ezetimibe-loaded solid dispersion.

PubMed

Rashid, Rehmana; Kim, Dong Wuk; Din, Fakhar Ud; Mustapha, Omer; Yousaf, Abid Mehmood; Park, Jong Hyuck; Kim, Jong Oh; Yong, Chul Soon; Choi, Han-Gon

2015-10-05

The purpose of this research was to evaluate the effect of the HPC (hydroxypropylcellulose) and Tween 80 on the physicochemical properties and oral bioavailability of ezetimibe-loaded solid dispersions. The binary solid dispersions were prepared with drug and various amounts of HPC. Likewise, ternary solid dispersions were prepared with different ratios of drug, HPC and Tween 80. Both types of solid dispersions were prepared using the solvent evaporation method. Their aqueous solubility, physicochemical properties, dissolution and oral bioavailability were investigated in comparison with the drug powder. All the solid dispersions significantly improved the drug solubility and dissolution. As the amount of HPC increased in the binary solid dispersions to 10-fold, the drug solubility and dissolution were increased accordingly. However, further increase in HPC did not result in significant differences among them. Similarly, up to 0.1-fold, Tween 80 increased the drug solubility in the ternary solid dispersions followed by no significant change. However, Tween 80 hardly affected the drug dissolution. The physicochemical analysis proved that the drug in binary and ternary solid dispersion was existed in the amorphous form. The particle-size measurements of these formulations were also not significantly different from each other, which showed that Tween 80 had no impact on physicochemical properties. The ezetimibe-loaded binary and ternary solid dispersions gave 1.6- and 1.8-fold increased oral bioavailability in rats, respectively, as compared to the drug powder; however, these values were not significantly different from each other. Thus, HPC greatly affected the solubility, dissolution and oral bioavailability of drug, but Tween 80 hardly did. Furthermore, this ezetimibe-loaded binary solid dispersion prepared only with HPC would be suggested as a potential formulation for oral administration of ezetimibe. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation of mechanical and microstructural properties of Zircaloy-4 under different experimental conditions

DOE PAGES

Silva, Chinthaka M.; Leonard, Keith J.; Van Abel, Eric; ...

2017-12-09

Here two types of Zircaloy-4 (alpha-annealed and beta-quenched) were investigated in their different forms. It was found that mechanical properties of Zircaloy-4 are affected significantly by welding and hydrogen-charging followed by neutron irradiation. Evaluation of microstructural properties of samples showed that these changes are mainly due to the formation of secondary phases such as hydrides—mostly along grain boundaries, dislocation channeling and their disruptions, and the increase in the type dislocation loops.

Investigation of mechanical and microstructural properties of Zircaloy-4 under different experimental conditions

NASA Astrophysics Data System (ADS)

Silva, Chinthaka M.; Leonard, Keith J.; Van Abel, Eric; Geringer, J. Wilna; Bryan, Chris D.

2018-02-01

Two types of Zircaloy-4 (alpha-annealed and beta-quenched) were investigated in their different forms. It was found that mechanical properties of Zircaloy-4 are affected significantly by welding and hydrogen-charging followed by neutron irradiation. Evaluation of microstructural properties of samples showed that these changes are mainly due to the formation of secondary phases such as hydrides-mostly along grain boundaries, dislocation channeling and their disruptions, and the increase in the type dislocation loops.

The statistical average of optical properties for alumina particle cluster in aircraft plume

NASA Astrophysics Data System (ADS)

Li, Jingying; Bai, Lu; Wu, Zhensen; Guo, Lixin

2018-04-01

We establish a model for lognormal distribution of monomer radius and number of alumina particle clusters in plume. According to the Multi-Sphere T Matrix (MSTM) theory, we provide a method for finding the statistical average of optical properties for alumina particle clusters in plume, analyze the effect of different distributions and different detection wavelengths on the statistical average of optical properties for alumina particle cluster, and compare the statistical average optical properties under the alumina particle cluster model established in this study and those under three simplified alumina particle models. The calculation results show that the monomer number of alumina particle cluster and its size distribution have a considerable effect on its statistical average optical properties. The statistical average of optical properties for alumina particle cluster at common detection wavelengths exhibit obvious differences, whose differences have a great effect on modeling IR and UV radiation properties of plume. Compared with the three simplified models, the alumina particle cluster model herein features both higher extinction and scattering efficiencies. Therefore, we may find that an accurate description of the scattering properties of alumina particles in aircraft plume is of great significance in the study of plume radiation properties.

The Effect of Different Mixing Methods on Working Time, Setting Time, Dimensional Changes and Film Thickness of Mineral Trioxide Aggregate and Calcium-Enriched Mixture.

PubMed

Shahi, Shahriar; Ghasemi, Negin; Rahimi, Saeed; Yavari, Hamidreza; Janani, Maryam; Mokhtari, Hadi; Bahari, Mahmood; Rabbani, Parastu

2015-01-01

The aim of the present study was to evaluate the effect of different mixing techniques (conventional, amalgamator and ultrasonic mixing) on the physical properties the working time (WT), setting time (ST), dimensional changes (DC) and film thickness (FT)] of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA). The mentioned physical properties were determined using the ISO 6786:2001 specification. Six samples of each material were prepared for three mixing techniques (totally 36 samples). Data were analyzed using descriptive statistics, two-way ANOVA and Post Hoc Tukey's tests. The level of significance was defined at 0.05. Irrespective of mixing technique, there was no significant difference between the WT and FT of the tested materials. Except for the DC of MTA and the FT of the all materials, other properties were significantly affected with mixing techniques (P<0.05). The ultrasonic technique decreased the ST of MTA and CEM cement and increased the WT of CEM cement (P<0.05). The mixing technique of the materials had no significant effect on the dimensional changes of MTA and the film thickness of both materials.

Rheological properties of cross-linked hyaluronic acid dermal fillers.

PubMed

Santoro, Stefano; Russo, Luisa; Argenzio, Vincenzo; Borzacchiello, Assunta

2011-01-01

Ha based dermal fillers in recent years aroused big interest in the area of cosmetic surgery for the rejuvenation of the dermis. There is not a ideal dermal filler (DF) for all applications and in commerce there are many types of DF that differ for their chemical-physical properties. So the aim of this paper is to correlate the rheological and physical properties of different DF to their clinical effectiveness. In this frame the samples have been subjected to oscillation dynamic rheological and steady shear measurements. Our results demonstrate that the viscoelastic properties of different DF varie strongly also considering fillers of the same family. Furthermore it was found that the materials physical properties influence significantly the performance of dermal filler. In particular the clinical data appear to correlate with the concentration of the polymer and with the product between the concentration and the percent elasticity, so these should be crucial parameters for the clinical performance of DF. So rheological data can be a tool to have an indication on the efficacy and longevity of DF but it has to be considered that production technology, in-vivo-conditions, injector skills and experience influence them also significantly.

Atomic force microscopy studies on cellular elastic and viscoelastic properties.

PubMed

Li, Mi; Liu, Lianqing; Xi, Ning; Wang, Yuechao

2018-01-01

In this work, a method based on atomic force microscopy (AFM) approach-reside-retract experiments was established to simultaneously quantify the elastic and viscoelastic properties of single cells. First, the elastic and viscoelastic properties of normal breast cells and cancerous breast cells were measured, showing significant differences in Young's modulus and relaxation times between normal and cancerous breast cells. Remarkable differences in cellular topography between normal and cancerous breast cells were also revealed by AFM imaging. Next, the elastic and viscoelasitc properties of three other types of cell lines and primary normal B lymphocytes were measured; results demonstrated the potential of cellular viscoelastic properties in complementing cellular Young's modulus for discerning different states of cells. This research provides a novel way to quantify the mechanical properties of cells by AFM, which allows investigation of the biomechanical behaviors of single cells from multiple aspects.

The effects of trawling on the properties of surface sediments in the Lagoon of Venice, Italy.

NASA Astrophysics Data System (ADS)

Aspden, R.; Vardy, S.; Perkins, R.; Davidson, I.; Paterson, D. M.

2003-04-01

The effects of trawling for clams in two differently impacted areas of the Lagoon of Venice were investigated. The Lagoon has an area of 55,000 hectares and the trawling of clams (Tapes phippinarum) has important socio-economic and environmental implications for the area. Bottom trawling has been shown to have large disruptive effects on the structure of benthic communities but the relationship of this to the stability and structure of the surface sediments is still unclear. The sediment stability, grain size, bulk and colloidal carbohydrate content, total organic carbon, chlorophyll a content, and sediment dry bulk density were measured in order to determine the effects of dredging on the physical and biological properties of the lagoon surface sediments. The sediments were more stable at the less impacted site and biological measurements from the same site indicated a relatively low capacity for biogenic stabilisation of sediments. Measurements were taken before and after trawling had occurred. At the less impacted site all biological properties were significantly different before and after the disturbance event, the only physical property to be significantly different was water content. At the highly impacted site the disturbance event had only a small effect on the biological and physical properties of the sediments. Only chlorophyll a content was significantly different before and after the trawl. The results suggest that frequent trawling of the lagoon will reduce the stability of the surface sediments due to the effects on the bulk strength of the sediments and on the biological status of the surface sediments.

A Study of Physicochemical Properties of Subcutaneous Fat of the Abdomen and its Implication in Abdominal Obesity.

PubMed

Pandey, Arvind Kumar; Kumar, Pramod; Kodavoor, Srinivas Aithal; Kotian, Sushma Rama; Yathdaka, Sudhakar Narahari; Nayak, Dayanand; Souza, Anne D; Souza, Antony Sylvan D

2016-05-01

The lower abdominal obesity is more resistant to absorption as compared to that of upper abdomen. Differences in the physicochemical properties of the subcutaneous fat of the upper and lower abdomen may be responsible for this variation. There is paucity of the scientific literature on the physicochemical properties of the subcutaneous fat of abdomen. The present study was undertaken to create a database of physicochemical properties of abdominal subcutaneous fat. The samples of subcutaneous fat from upper and lower abdomen were collected from 40 fresh autopsied bodies (males 33, females 7). The samples were prepared for physicochemical analysis using organic and inorganic solvents. Various physicochemical properties of the fat samples analysed were surface tension, viscosity, specific gravity, specific conductivity, iodine value and thermal properties. Data was analysed by paired and independent sample t-tests. There was a statistically significant difference in all the physicochemical parameters between males and females except surface tension (organic) and surface tension (inorganic) of upper abdominal fat, and surface tension (organic) of lower abdominal fat. In males, viscosity of upper abdominal fat was more compared to that of lower abdomen (both organic and inorganic) unlike the specific conductivity that was higher for the lower abdominal fat as compared to that of the upper abdomen. In females there were statistically significant higher values of surface tension (inorganic) and specific gravity (organic) of the upper abdomen fat as compared to that of lower abdomen. The initial and final weight loss of the lower abdominal fat as indicated by Thermo Gravimetric Analysis was significantly more in males than in female. The difference in the physicochemical properties of subcutaneous fat between upper and lower abdomen and between males and females could be responsible for the variant behaviour of subcutaneous abdominal fat towards resorption.

Quantifying Differences in the Impact of Variable Chemistry on Equilibrium Uranium(VI) Adsorption Properties of Aquifer Sediments

PubMed Central

2011-01-01

Uranium adsorption–desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500–1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2–, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logKc) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logKc values. Using this approach, logKc values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (<0.063 mm) of another could be demonstrated despite the fines requiring a different reaction stoichiometry. Estimates of logKc uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors. PMID:21923109

Quantifying differences in the impact of variable chemistry on equilibrium Uranium(VI) adsorption properties of aquifer sediments.

PubMed

Stoliker, Deborah L; Kent, Douglas B; Zachara, John M

2011-10-15

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO₂²⁺ + 2CO₃²⁻ = >SOUO₂(CO₃HCO₃)²⁻, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logK(c)) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logK(c) values. Using this approach, logK(c) values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (< 0.063 mm) of another could be demonstrated despite the fines requiring a different reaction stoichiometry. Estimates of logK(c) uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.

A general model for estimating lower extremity inertial properties of individuals with transtibial amputation.

PubMed

Ferris, Abbie E; Smith, Jeremy D; Heise, Gary D; Hinrichs, Richard N; Martin, Philip E

2017-03-21

Lower extremity joint moment magnitudes during swing are dependent on the inertial properties of the prosthesis and residual limb of individuals with transtibial amputation (TTA). Often, intact limb inertial properties (INTACT) are used for prosthetic limb values in an inverse dynamics model even though these values overestimate the amputated limb's inertial properties. The purpose of this study was to use subject-specific (SPECIFIC) measures of prosthesis inertial properties to generate a general model (GENERAL) for estimating TTA prosthesis inertial properties. Subject-specific mass, center of mass, and moment of inertia were determined for the shank and foot segments of the prosthesis (n=11) using an oscillation technique and reaction board. The GENERAL model was derived from the means of the SPECIFIC model. Mass and segment lengths are required GENERAL model inputs. Comparisons of segment inertial properties and joint moments during walking were made using three inertial models (unique sample; n=9): (1) SPECIFIC, (2) GENERAL, and (3) INTACT. Prosthetic shank inertial properties were significantly smaller with the SPECIFIC and GENERAL model than the INTACT model, but the SPECIFIC and GENERAL model did not statistically differ. Peak knee and hip joint moments during swing were significantly smaller for the SPECIFIC and GENERAL model compared with the INTACT model and were not significantly different between SPECIFIC and GENERAL models. When subject-specific measures are unavailable, using the GENERAL model produces a better estimate of prosthetic side inertial properties resulting in more accurate joint moment measurements for individuals with TTA than the INTACT model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rheometric properties of canine vocal fold tissues: Variation with anatomic location

PubMed Central

Kimura, Miwako; Mau, Ted; Chan, Roger W.

2010-01-01

Objective To evaluate the in vitro rheometric properties of the canine vocal fold lamina propria and muscle at phonatory frequencies, and their changes with anatomic location. Methods Six canine larynges were harvested immediately postmortem. Viscoelastic shear properties of anterior, middle, and posterior portions of the vocal fold cover (lamina propria) as well as those of the medial thyroarytenoid (TA) muscle (vocalis muscle) were quantified by a linear, controlled-strain simple-shear rheometer. Measurements of elastic shear modulus (G’) and dynamic viscosity (η’) of the specimens were conducted with small-amplitude sinusoidal shear deformation over a frequency range of 1 Hz to 250 Hz. Results All specimens showed similar frequency dependence of the viscoelastic functions, with G’ gradually increasing with frequency and η’ decreasing with frequency monotonically. G’ and η’ of the canine vocalis muscle were significantly higher than those of the canine vocal fold cover, and η’ of the canine vocal fold cover was significantly higher than that of the human vocal fold cover. There were no significant differences in G’ and in η’ between different portions of the canine vocal fold cover. Conclusion These preliminary data based on the canine model suggested that the vocalis muscle, while in a relaxed state in vitro, is significantly stiffer and more viscous than the vocal fold cover during vibration at phonatory frequencies. For large-amplitude vocal fold vibration involving the medial portion of the TA muscle, such distinct differences in viscoelastic properties of different layers of the vocal fold should be taken into account in multi-layered biomechanical models of phonation. PMID:21035291

Characterization of temperature-dependent optical material properties of polymer powders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laumer, Tobias; SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen; CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen

2015-05-22

In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystallinemore » thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.« less

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

NASA Astrophysics Data System (ADS)

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés Abellán, M.; de Las Heras, J.

2014-10-01

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonize soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments five years after the fire event were selected. A mature Aleppo pine stand unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Thus, the long-term consequences and post-fire silvicultural management in the form of thinning have a significant effect on the site recovery after fire. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation restoration normalises microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors of soil properties after 17 years.

Investigating changes in brain network properties in HIV-associated neurocognitive disease (HAND) using mutual connectivity analysis (MCA)

NASA Astrophysics Data System (ADS)

Abidin, Anas Zainul; D'Souza, Adora M.; Nagarajan, Mahesh B.; Wismüller, Axel

2016-03-01

About 50% of subjects infected with HIV present deficits in cognitive domains, which are known collectively as HIV associated neurocognitive disorder (HAND). The underlying synaptodendritic damage can be captured using resting state functional MRI, as has been demonstrated by a few earlier studies. Such damage may induce topological changes of brain connectivity networks. We test this hypothesis by capturing the functional interdependence of 90 brain network nodes using a Mutual Connectivity Analysis (MCA) framework with non-linear time series modeling based on Generalized Radial Basis function (GRBF) neural networks. The network nodes are selected based on the regions defined in the Automated Anatomic Labeling (AAL) atlas. Each node is represented by the average time series of the voxels of that region. The resulting networks are then characterized using graph-theoretic measures that quantify various network topology properties at a global as well as at a local level. We tested for differences in these properties in network graphs obtained for 10 subjects (6 male and 4 female, 5 HIV+ and 5 HIV-). Global network properties captured some differences between these subject cohorts, though significant differences were seen only with the clustering coefficient measure. Local network properties, such as local efficiency and the degree of connections, captured significant differences in regions of the frontal lobe, precentral and cingulate cortex amongst a few others. These results suggest that our method can be used to effectively capture differences occurring in brain network connectivity properties revealed by resting-state functional MRI in neurological disease states, such as HAND.

Effects of mechanical properties of thermoplastic materials on the initial force of thermoplastic appliances.

PubMed

Kohda, Naohisa; Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A; Ahluwalia, Karamdeep S; Mizoguchi, Itaru

2013-05-01

To measure the forces delivered by thermoplastic appliances made from three materials and investigate effects of mechanical properties, material thickness, and amount of activation on orthodontic forces. Three thermoplastic materials, Duran (Scheu Dental), Erkodur (Erkodent Erich Kopp GmbH), and Hardcast (Scheu Dental), with two different thicknesses were selected. Values of elastic modulus and hardness were obtained from nanoindentation measurements at 28°C. A custom-fabricated system with a force sensor was employed to obtain measurements of in vitro force delivered by the thermoplastic appliances for 0.5-mm and 1.0-mm activation for bodily tooth movement. Experimental results were subjected to several statistical analyses. Hardcast had significantly lower elastic modulus and hardness than Duran and Erkodur, whose properties were not significantly different. Appliances fabricated from thicker material (0.75 mm or 0.8 mm) always produced significantly greater force than those fabricated from thinner material (0.4 mm or 0.5 mm). Appliances with 1.0-mm activation produced significantly lower force than those with 0.5-mm activation, except for 0.4-mm thick Hardcast appliances. A strong correlation was found between mechanical properties of the thermoplastic materials and force produced by the appliances. Orthodontic forces delivered by thermoplastic appliances depend on the material, thickness, and amount of activation. Mechanical properties of the polymers obtained by nanoindentation testing are predictive of force delivery by these appliances.

A large-scale measurement of dielectric properties of normal and malignant colorectal tissues obtained from cancer surgeries at Larmor frequencies.

PubMed

Li, Zhou; Deng, Guanhua; Li, Zhe; Xin, Sherman Xuegang; Duan, Song; Lan, Maoying; Zhang, Sa; Gao, Yixin; He, Jun; Zhang, Songtao; Tang, Hongming; Wang, Weiwei; Han, Shuai; Yang, Qing X; Zhuang, Ling; Hu, Jiani; Liu, Feng

2016-11-01

Knowledge of dielectric properties of malignant human tissues is necessary for the recently developed magnetic resonance (MR) technique called MR electrical property tomography. This technique may be used in early tumor detection based on the obvious differentiation of the dielectric properties between normal and malignant tissues. However, the dielectric properties of malignant human tissues in the scale of the Larmor frequencies are not completely available in the literature. In this study, the authors focused only on the dielectric properties of colorectal tumor tissue. The dielectric properties of 504 colorectal malignant samples excised from 85 patients in the scale of the Larmor frequencies were measured using the precision open-ended coaxial probe method. The obtained complex-permittivity data were fitted to the single-pole Cole-Cole model. The median permittivity and conductivity for the malignant tissue sample were 79.3 and 0.881 S/m at 128 MHz, which were 14.6% and 17.0% higher, respectively, than those of normal tissue samples. Significant differences between normal and malignant tissues were found for the dielectric properties (p < 0.05). Experimental results indicated that the dielectric properties were significantly different between normal and malignant tissues for colorectal tissue. This large-scale clinical measurement provides more subtle base data to validate the technique of MR electrical property tomography.

Different behavioral effect dose–response profiles in mice exposed to two-carbon chlorinated hydrocarbons: Influence of structural and physical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Umezu, Toyoshi, E-mail: umechan2@nies.go.jp; Shibata, Yasuyuki, E-mail: yshibata@nies.go.jp

2014-09-01

The present study aimed to clarify whether dose–response profiles of acute behavioral effects of 1,2-dichloroethane (DCE), 1,1,1-trichloroethane (TCE), trichloroethylene (TRIC), and tetrachloroethylene (PERC) differ. A test battery involving 6 behavioral endpoints was applied to evaluate the effects of DCE, TCE, TRIC, and PERC in male ICR strain mice under the same experimental conditions. The behavioral effect dose–response profiles of these compounds differed. Regression analysis was used to evaluate the relationship between the dose–response profiles and structural and physical properties of the compounds. Dose–response profile differences correlated significantly with differences in specific structural and physical properties. These results suggest that differencesmore » in specific structural and physical properties of DCE, TCE, TRIC, and PERC are responsible for differences in behavioral effects that lead to a variety of dose–response profiles. - Highlights: • We examine effects of 4 chlorinated hydrocarbons on 6 behavioral endpoints in mice. • The behavioral effect dose–response profiles for the 4 compounds are different. • We utilize regression analysis to clarify probable causes of the different profiles. • The compound's physicochemical properties probably produce the different profiles.« less

Important physical properties of peat materials

Treesearch

D.H. Boelter

1968-01-01

Peat materials from 12 bogs in northern Minnesota, U.S.A., showed significant differences in physical properties. It is pointed out that 1) these properties can be related to the hydrology of organic soils only if the soils represent undisturbed field conditions, and 2) volumetric expressions of water content are necessary to correctly evaluate the amount of water in a...

Outdoor weathering of facial prosthetic elastomers differing in Durometer hardness.

PubMed

Willett, Emily S; Beatty, Mark W

2015-03-01

Facial prosthetic elastomers with wide ranges in hardness are available, yet material weatherability is unknown. The purpose of this study was to assess color, Durometer hardness, and tensile property changes after 3000 hours of outdoor weathering. Unpigmented elastomers with Durometer hardness 5, 30, 50, 70, and A-2186 were polymerized into dumbbells (ASTM D412) and disks, 34 mm in diameter by 6 mm thick. Materials were subjected to outdoor or time passage environments for 3000 hours. CIELab color (n=5), Durometer hardness (n=5), and tensile mechanical properties (n=10) were measured at 0 and 3000 hours, and group differences were assessed by material and weathering condition (ANOVA/Tukey, α=.05). Except for A-2186, the mean Durometer changes for all materials were 1 unit or less, with no significant differences observed between time passage and weathered groups (P≥.05). Three-thousand-hour tensile mechanical property results demonstrated nonsignificant differences between time passage and weathered materials but significantly changed properties from immediately tested materials (P<.001). Outdoor weathering induced perceptible but acceptable color changes (1.7≤ΔE*≤2.6) for elastomers with Durometer hardness 5 and 30 and A-2186. With a few exceptions, outdoor weathering produced relatively small changes in color, Durometer hardness, or tensile properties compared with time passage. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Factors of soil diversity in the Batumi delta (Georgia)

NASA Astrophysics Data System (ADS)

Turgut, Bülent; Ateş, Merve

2017-01-01

The aim of this study was to determine certain basic properties of soils in the Batumi delta (southwestern Georgia) to determine the relationships of studied properties and to identify differences with regards to these properties between different sampling sites in the delta that were selected based on the delta morphology. In this context, a total of 125 soil samples were collected from five different sampling sites, and the clay, silt and sand content of the samples were determined along with their mean weight diameter (MWD) values, aggregate stability (AS) values, amount of water retained under -33 (FC) and -1500 kPa (WP) pressure and organic matter (OM) content. Correlation analysis indicated that clay content and OM were positively correlated with MWD, and OM was positively correlated with AS. However, the sand content was found to be negatively correlated with MWD. In addition, clay, silt and OM content were positive correlated with FC and WP. Variance analysis results determined statistically significant differences between the sampling sites with respect to all of the evaluated properties. The active delta section of the study area was characterized by high sand content, while the lower delta plain was characterized by high OM and AS values, and the upper delta plain was characterized by high MWD values, high FC and WP moisture content levels and high clay and silt content. In conclusion, it was demonstrated that the examined properties were significantly affected by the different morphological positions and usages of these different areas. These results may help with the management of agricultural lands in the Batumi delta, which has never been studied before.

A comprehensive study of catalytic, morphological and electronic properties of ligand-protected gold nanoclusters using XPS, STM, XAFS, and TPD techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Qiyuan; Cen, Jiajie; Zhao, Yue

Ultra-small gold nanoclusters were synthesized via a ligand exchange method and deposited onto different TiO2 supports to study their properties. STM imaging revealed that the as-synthesized gold nanoclusters had 2-D morphology consisting of monolayers of gold atoms. In conclusion, subsequent XPS, XAFS, and CO oxidation TPD results indicated that heat treatments of gold clusters at different temperatures significantly altered their electronic and catalytic properties due to ligand deprotection and cluster agglomeration.

A comprehensive study of catalytic, morphological and electronic properties of ligand-protected gold nanoclusters using XPS, STM, XAFS, and TPD techniques

DOE PAGES

Wu, Qiyuan; Cen, Jiajie; Zhao, Yue; ...

2017-12-08

Ultra-small gold nanoclusters were synthesized via a ligand exchange method and deposited onto different TiO2 supports to study their properties. STM imaging revealed that the as-synthesized gold nanoclusters had 2-D morphology consisting of monolayers of gold atoms. In conclusion, subsequent XPS, XAFS, and CO oxidation TPD results indicated that heat treatments of gold clusters at different temperatures significantly altered their electronic and catalytic properties due to ligand deprotection and cluster agglomeration.

Investigation of Thermophysical Properties of Thermal Degraded Biodiesels

NASA Astrophysics Data System (ADS)

Regatieri, H. R.; Savi, E. L.; Lukasievicz, G. V. B.; Sehn, E.; Herculano, L. S.; Astrath, N. G. C.; Malacarne, L. C.

2018-06-01

Biofuels are an alternative to fossil fuels and can be made from many different raw materials. The use of distinct catalyst and production processes, feedstocks, and types of alcohol results in biofuels with different physical and chemical properties. Even though these diverse options for biodiesel production are considered advantageous, they may pose a setback when quality specifications are considered, since different properties are subject to different reactions during usage, storage and handling. In this work, we present a systematic characterization of biodiesels to investigate how accelerated thermal degradation affects fuel properties. Two different types of biodiesel, commercially obtained from distinct feedstocks, were tested. The thermal degradation process was performed by maintaining the temperature of the sample at 140°C under constant air flux for different times: 0 h, 3 h, 6 h, 9 h, 12 h, 24 h and 36 h. Properties such as density, viscosity, activation energy, volumetric thermal expansion coefficient, gross caloric value, acid value, infrared absorption, and temperature coefficient of the refractive index were used to study the thermal degradation of the biodiesel samples. The results show a significant difference in fuel properties before and after the thermal degradation process suggesting the formation of undesirable compounds. All the properties mentioned above were found to be useful to determine whether a biodiesel sample underwent thermal degradation. Moreover, viscosity and acid value were found to be the most sensitive characteristics to detect the thermal degradation process.

Structural adaptation of the subunit interface of oligomeric thermophilic and hyperthermophilic enzymes.

PubMed

Maugini, Elisa; Tronelli, Daniele; Bossa, Francesco; Pascarella, Stefano

2009-04-01

Enzymes from thermophilic and, particularly, from hyperthermophilic organisms are surprisingly stable. Understanding of the molecular origin of protein thermostability and thermoactivity attracted the interest of many scientist both for the perspective comprehension of the principles of protein structure and for the possible biotechnological applications through application of protein engineering. Comparative studies at sequence and structure levels were aimed at detecting significant differences of structural parameters related to protein stability between thermophilic and hyperhermophilic structures and their mesophilic homologs. Comparative studies were useful in the identification of a few recurrent themes which the evolution utilized in different combinations in different protein families. These studies were mostly carried out at the monomer level. However, maintenance of a proper quaternary structure is an essential prerequisite for a functional macromolecule. At the environmental temperatures experienced typically by hyper- and thermophiles, the subunit interactions mediated by the interface must be sufficiently stable. Our analysis was therefore aimed at the identification of the molecular strategies adopted by evolution to enhance interface thermostability of oligomeric enzymes. The variation of several structural properties related to protein stability were tested at the subunit interfaces of thermophilic and hyperthermophilic oligomers. The differences of the interface structural features observed between the hyperthermophilic and thermophilic enzymes were compared with the differences of the same properties calculated from pairwise comparisons of oligomeric mesophilic proteins contained in a reference dataset. The significance of the observed differences of structural properties was measured by a t-test. Ion pairs and hydrogen bonds do not vary significantly while hydrophobic contact area increases specially in hyperthermophilic interfaces. Interface compactness also appears to increase in the hyperthermophilic proteins. Variations of amino acid composition at the interfaces reflects the variation of the interface properties.

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

NASA Astrophysics Data System (ADS)

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

2015-02-01

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

The influence of API concentration on the roller compaction process: modeling and prediction of the post compacted ribbon, granule and tablet properties using multivariate data analysis.

PubMed

Boersen, Nathan; Carvajal, M Teresa; Morris, Kenneth R; Peck, Garnet E; Pinal, Rodolfo

2015-01-01

While previous research has demonstrated roller compaction operating parameters strongly influence the properties of the final product, a greater emphasis might be placed on the raw material attributes of the formulation. There were two main objectives to this study. First, to assess the effects of different process variables on the properties of the obtained ribbons and downstream granules produced from the rolled compacted ribbons. Second, was to establish if models obtained with formulations of one active pharmaceutical ingredient (API) could predict the properties of similar formulations in terms of the excipients used, but with a different API. Tolmetin and acetaminophen, chosen for their different compaction properties, were roller compacted on Fitzpatrick roller compactor using the same formulation. Models created using tolmetin and tested using acetaminophen. The physical properties of the blends, ribbon, granule and tablet were characterized. Multivariate analysis using partial least squares was used to analyze all data. Multivariate models showed that the operating parameters and raw material attributes were essential in the prediction of ribbon porosity and post-milled particle size. The post compacted ribbon and granule attributes also significantly contributed to the prediction of the tablet tensile strength. Models derived using tolmetin could reasonably predict the ribbon porosity of a second API. After further processing, the post-milled ribbon and granules properties, rather than the physical attributes of the formulation were needed to predict downstream tablet properties. An understanding of the percolation threshold of the formulation significantly improved the predictive ability of the models.

Thresholds of skin sensitivity are partially influenced by mechanical properties of the skin on the foot sole

PubMed Central

Strzalkowski, Nicholas D J; Triano, John J; Lam, Chris K; Templeton, Cale A; Bent, Leah R

2015-01-01

Across the foot sole, there are vibration and monofilament sensory differences despite an alleged even distribution of cutaneous afferents. Mechanical property differences across foot sole sites have been proposed to account for these differences. Vibration (VPT; 3 Hz, 40 Hz, 250 Hz), and monofilament (MF) perception threshold measurements were compared with skin hardness, epidermal thickness, and stretch response across five foot sole locations in young healthy adults (n = 22). Perceptual thresholds were expected to correlate with all mechanical property measurements to help address sensitivity differences between sites. Following this hypothesis, the MedArch was consistently found to be the thinnest and softest site and demonstrated the greatest sensitivity. Conversely, the Heel was found to be the thickest and hardest site, and was relatively insensitive across perceptual tests. Site differences were not observed for epidermal stretch response measures. Despite an apparent trend of elevated sensory threshold at harder and thicker sites, significant correlations between sensitivity measures and skin mechanical properties were not observed. Skin hardness and epidermal thickness appeared to have a negligible influence on VPT and minor influence on MF within this young healthy population. When normalized (% greater or smaller than subject mean) to the subject mean for each variable, significant positive correlations were observed between MF and skin hardness (R2 = 0.422, P < 0.0001) and epidermal thickness (R2 = 0.433, P < 0.0001) providing evidence that skin mechanics can influence MF threshold. In young healthy adults, differences in sensitivity are present across the foot sole, but cannot solely be accounted for by differences in the mechanical properties of the skin. PMID:26059035

Microstructural Evolution and Mechanical Properties in Superlight Mg-Li Alloy Processed by High-Pressure Torsion

PubMed Central

Su, Qian; Xu, Jie; Li, Yuqiao; Yoon, Jae Ik; Shan, Debin; Guo, Bin; Kim, Hyoung Seop

2018-01-01

Microstructural evolution and mechanical properties of LZ91 Mg-Li alloy processed by high-pressure torsion (HPT) at an ambient temperature were researched in this paper. The microstructure analysis demonstrated that significant grain refinement was achieved after HPT processing with an average grain size reducing from 30 μm (the as-received condition) to approximately 230 nm through 10 turns. X-ray diffraction analysis revealed LZ91 alloy was consisted of α phase (hexagonal close-packed structure, hcp) and β phase (body-centered cubic structure, bcc) before and after HPT processing. The mean value of microhardness increased with the increasing number of HPT turns. This significantly increased hardness of specimens can be explained by Hall-Petch strengthening. Simultaneously, the distribution of microhardness along the specimens was different from other materials after HPT processing due to the different mechanical properties of two different phases. The mechanical properties of LZ91 alloy processed by HPT were assessed by the micro-tensile testing at 298, 373, 423, and 473 K. The results demonstrate that the ultra-fine grain LZ91 Mg-Li alloy exhibits excellent mechanical properties: tensile elongation is approximately 400% at 473 K with an initial strain rate of 1 × 10−2 s−1. PMID:29652807

The effects of different processing conditions on biogenic amine formation and some qualitative properties in pastırma.

PubMed

Hazar, Fatma Yağmur; Kaban, Güzin; Kaya, Mükerrem

2017-11-01

Pastırma, a Turkish dry-cured meat product, was cured at two different temperatures (4 or 10 °C) with two different curing agents (150 mg/kg NaNO 2 or 300 mg/kg KNO 3 ). The aim of this research was to determine the effects of these factors on biogenic amine content and other qualitative properties (pH, a w , color, residual nitrite, TBARS, NPN-M, microbiological properties). Residual nitrite was below 10 mg/kg in all samples. Both the curing agent and temperature were found to have a very significant effect on the TBARS value, and the curing agent had a significant effect on the NPN-M content. Curing at 10 °C increased the L* value; the use of nitrate increased the a* value. The use of nitrite had a negative effect on the growth of lactic acid bacteria. Micrococcus/Staphylococcus showed good growth in the presence of nitrate. In all samples, Enterobacteriaceae counts were below detectable levels. Neither temperature nor curing agent had significant effects on the amounts of tryptamine, cadaverine, histamine, tyramine, or spermine. There were very significant effects of temperature on the amount of putrescine and of the curing agent on the amount of spermidine.

The effects of human milk fortification on nutrients and milk properties.

PubMed

Donovan, R; Kelly, S G; Prazad, P; Talaty, P N; Lefaiver, C; Hastings, M L; Everly, D N

2017-01-01

To investigate the effects of fortification and storage on nutrients and properties of various human milk (HM) types. Mother's own milk (MOM) and pasteurized donor human milk (DHM; n=118) were analyzed pre- and post fortification with Enfamil and Similac human milk fortifier (EHMF and SHMF) before and after 24 h of refrigerated storage. Milk fortified with SHMF had significantly greater osmolality, pH and lipase activity than EHMF. Changes in protein, pH and osmolality following refrigerated storage differed between fortifiers. When milk type was factored into the analysis, protein and lipase activity changes in fresh MOM differed significantly from DHM and frozen MOM. Analysis of UNF HM found higher protein levels in preterm vs term samples and in MOM vs DHM. Nutrient composition of HM varies significantly by milk type. Although fortifiers enhance select nutrients, each has the potential to affect HM properties in a unique way and these affects may vary by milk type.

Stochasticity of bacterial attachment and its predictability by the extended derjaguin-landau-verwey-overbeek theory.

PubMed

Chia, Teck Wah R; Nguyen, Vu Tuan; McMeekin, Thomas; Fegan, Narelle; Dykes, Gary A

2011-06-01

Bacterial attachment onto materials has been suggested to be stochastic by some authors but nonstochastic and based on surface properties by others. We investigated this by attaching pairwise combinations of two Salmonella enterica serovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each of S. enterica serovar Typhimurium, S. enterica serovar Infantis, or S. enterica serovar Virchow (all with similar physicochemical and attachment abilities) in ratios of 0.428, 1, and 2.333 onto glass, stainless steel, Teflon, and polysulfone. Attached bacterial cells were recovered and counted. If the ratio of attached cells of each Salmonella serovar pair recovered was the same as the initial inoculum ratio, the attachment process was deemed stochastic. Experimental outcomes from the study were compared to those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Significant differences (P < 0.05) between the initial and the attached ratios for serovar pairs containing S. Sofia S1296a for all different ratios were apparent for all materials. For S. Sofia S1635-containing pairs, 7 out of 12 combinations of serovar pairs and materials had attachment ratios not significantly different (P > 0.05) from the initial ratio of 0.428. Five out of 12 and 10 out of 12 samples had attachment ratios not significantly different (P > 0.05) from the initial ratios of 1 and 2.333, respectively. These results demonstrate that bacterial attachment to different materials is likely to be nonstochastic only when the key physicochemical properties of the bacteria were significantly different (P < 0.05) from each other. XDLVO theory could successfully predict the attachment of some individual isolates to particular materials but could not be used to predict the likelihood of stochasticity in pairwise attachment experiments.

Investigation of global and local network properties of music perception with culturally different styles of music.

PubMed

Li, Yan; Rui, Xue; Li, Shuyu; Pu, Fang

2014-11-01

Graph theoretical analysis has recently become a popular research tool in neuroscience, however, there have been very few studies on brain responses to music perception, especially when culturally different styles of music are involved. Electroencephalograms were recorded from ten subjects listening to Chinese traditional music, light music and western classical music. For event-related potentials, phase coherence was calculated in the alpha band and then constructed into correlation matrices. Clustering coefficients and characteristic path lengths were evaluated for global properties, while clustering coefficients and efficiency were assessed for local network properties. Perception of light music and western classical music manifested small-world network properties, especially with a relatively low proportion of weights of correlation matrices. For local analysis, efficiency was more discernible than clustering coefficient. Nevertheless, there was no significant discrimination between Chinese traditional and western classical music perception. Perception of different styles of music introduces different network properties, both globally and locally. Research into both global and local network properties has been carried out in other areas; however, this is a preliminary investigation aimed at suggesting a possible new approach to brain network properties in music perception. Copyright © 2014 Elsevier Ltd. All rights reserved.

New findings confirm the viscoelastic behaviour of the inter-lamellar matrix of the disc annulus fibrosus in radial and circumferential directions of loading.

PubMed

Tavakoli, J; Costi, J J

2018-04-15

While few studies have improved our understanding of composition and organization of elastic fibres in the inter-lamellar matrix (ILM), its clinical relevance is not fully understood. Moreover, no studies have measured the direct tensile and shear failure and viscoelastic properties of the ILM. Therefore, the aim of this study was, for the first time, to measure the viscoelastic and failure properties of the ILM in both the tension and shear directions of loading. Using an ovine model, isolated ILM samples were stretched to 40% of their initial length at three strain rates of 0.1%s -1 (slow), 1%s -1 (medium) and 10%s -1 (fast) and a ramp test to failure was performed at a strain rate of 10%s -1 . The findings from this study identified that the stiffness of the ILM was significantly larger at faster strain rates, and energy absorption significantly smaller, compared to slower strain rates, and the viscoelastic and failure properties were not significantly different under tension and shear loading. We found a strain rate dependent response of the ILM during dynamic loading, particularly at the fastest rate. The ILM demonstrated a significantly higher capability for energy absorption at slow strain rates compared to medium and fast strain rates. A significant increase in modulus was found in both loading directions and all strain rates, having a trend of larger modulus in tension and at faster strain rates. The finding of no significant difference in failure properties in both loading directions, was consistent with our previous ultra-structural studies that revealed a well-organized (±45°) elastic fibre orientation in the ILM. The results from this study can be used to develop and validate finite element models of the AF at the tissue scale, as well as providing new strategies for fabricating tissue engineered scaffolds. While few studies have improved our understanding of composition and organization of elastic fibres in the inter-lamellar matrix (ILM) of the annulus in the disc no studies have measured the direct mechanical failure and viscoelastic properties of the ILM. The findings from this study identified that the stiffness of the ILM was significantly larger at faster strain rates, and energy absorption significantly smaller, compared to slower strain rates. The failure properties of the ILM were not significantly different under tension and shear. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Post-wildfire management effects on short-term evolution of soil properties (Catalonia, Spain, SW-Europe).

PubMed

Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavier

2018-08-15

Post-fire management practices after wildfires have an important impact on soil properties. Nevertheless, little research has been carried out. The aim of this study is to examine the impact of different post-wildfire forest management practices in a 10-month period immediately after a severe wildfire on soil properties. Two months after a wildfire, three experimental areas were designed, each one with different post-fire management: Cut and Remove (CR) where burned trunks were cut after fire and removed manually from the area; No Treatment (NT) where no intervention was carried out; and, Cut and Leave (CL) where burned trunks were cut and left randomly on topsoil. In each treatment, we collected nine samples (0-5cm deep). In total, we sampled 27 samples in each sampling date, two and ten months after the wildfire. The properties analyzed were aggregate stability (AS), total nitrogen (TN), soil organic matter (SOM), inorganic carbon (IC), C/N ratio, pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K). Soil C/N ratio was significantly higher in CR and CL treatments 10months after fire comparing to 2months after. On the other hand, pH, extractable Ca, Mg and K were significantly higher in all the treatments 2months after fire than 10months after. Aggregate stability, TN and SOM were significantly higher in CR comparing to CL, 10months after the fire. IC was significantly higher in CL than in NT treatment, also, 10months after the fire. Electrical conductivity was significantly higher in CR and CL treatments 2months after fire comparing to 10months after. According to the results, CR and CL post-fire management did not differ importantly from the NT scenario, showing that manual wood management does not have detrimental impacts on soil properties compared to mechanical operations. Copyright © 2018 Elsevier B.V. All rights reserved.

Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging.

PubMed

Hersche, Sepp; Sifakakis, Iosif; Zinelis, Spiros; Eliades, Theodore

2017-02-01

The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and Vickers hardness (HV). These properties were determined employing instrumented indentation testing (IIT) with a Vickers indenter. The results were statistically analyzed by unpaired t-test (α=0.05). There were no statistically significant differences evidenced in surface morphology and elemental content between the control and the experimental group. These two groups of brackets showed no statistically significant difference in surface morphology. Moreover, the mean values of HM, EIT, ηIT, and HV did not reach statistical significance between the groups (p>0.05). Under the limitations of this study, it may be concluded that the surface elemental content and microstructure as well as the evaluated mechanical properties of the Incognito™ lingual brackets remain unaffected by intraoral aging.

Numerical investigation on the Ångström exponent of black carbon aerosol

NASA Astrophysics Data System (ADS)

Li, Ji; Liu, Chao; Yin, Yan; Kumar, K. Raghavendra

2016-04-01

Black carbon (BC) plays an important role on the global and regional climate, whereas there are significant uncertainties on its optical properties. Among various optical properties, the Ångström exponent (AE) indicates the spectral variation of the particle-optic interaction and is widely used to understand the aerosol properties. We consider the influence of BC geometry on its optical properties and assess the sensitivity of the AE to particle geometry and size distribution. The fractal aggregates with different fractal dimensions are used to represent realistic BC particles, and popular equivalent volume spherical and spheroidal models are also considered for comparison. Even if the fractal aggregates become highly compact and spherical, their optical properties are still significantly different from those of equivalent volume spheres or spheroids. Meanwhile, the Rayleigh-Debye-Gans approximation can hardly provide accurate results for all optical quantities of aggregates with different dimensions. The extinction Ångström exponent (EAE) and absorption Ångström exponent (AAE) are sensitive to both particle geometry and size distribution. With BC becoming more compact (from fractal aggregate to spheroid and to sphere), the AE becomes more sensitive to particle size distribution. The EAE and AAE of aggregates with different size distributions vary between 1.10-1.63 and 0.87-1.50, respectively, whereas those of the spheres or spheroids have wider ranges. Furthermore, the AE at smaller wavelengths (between 0.35 µm and 0.55 µm) is more sensitive to geometry and size distribution than that given by optical properties at larger wavelengths (between 0.55 µm and 0.88 µm).

Will Commodity Properties Affect Seller's Creditworthy: Evidence in C2C E-commerce Market in China

NASA Astrophysics Data System (ADS)

Peng, Hui; Ling, Min

This paper finds out that the credit rating level shows significant difference among different sub-commodity markets in E-commerce, which provides room for sellers to get higher credit rating by entering businesses with higher average credit level before fraud. In order to study the influence of commodity properties on credit rating, this paper analyzes how commodity properties affect average crediting rating through the degree of information asymmetry, returns and costs of fraud, credibility perception and fraud tolerance. Empirical study shows that Delivery, average trading volume, average price and complaint possibility have decisive impacts on credit performance; brand market share, the degree of standardization and the degree of imitation also have a relatively less significant effect on credit rating. Finally, this paper suggests that important commodity properties should be introduced to modify reputation system, for preventing credit rating arbitrage behavior where sellers move into low-rating commodity after being assigned high credit rating.

Tensile Properties of the Deep Transverse Metatarsal Ligament in Hallux Valgus: A CONSORT-Compliant Article.

PubMed

Abdalbary, Sahar Ahmed; Elshaarawy, Ehab A A; Khalid, Bahaa E A

2016-02-01

The deep transverse metatarsal ligament (DTML) connects the neighboring2 metatarsal heads and is one of the stabilizers connecting the lateral sesamoid and second metatarsal head. In this study, we aimed to determine the tensile properties of the DTML in normal specimens and to compare these results with hallux valgus specimens. We hypothesized that the tensile properties of the DTML would be different between the 2 groups of specimens.The DTML in the first interspace was dissected from 12 fresh frozen human cadaveric specimens. Six cadavers had bilateral hallux valgus and the other 6 cadavers had normal feet. The initial length (L0) and cross-sectional area (A0) of the DTML were measured using a digital caliper, and tensile tests with load failure were performed using a material testing machine.There were significant between-groups differences in the initial length (L0) P = 0.009 and cross-sectional area (A0) of the DTML P = 0.007. There were also significant between-groups differences for maximum force (N) P = 0.004, maximum distance (mm) P = 0.005, maximum stress (N/mm) P = 0.003, and maximum strain (%) P = 0.006.The DTML is an anatomical structure for which the tensile properties differ in hallux valgus.

Differences in Tribological Behaviors upon Switching Fixed and Moving Materials of Tribo-pairs including Metal and Polymer.

PubMed

Xu, Aijie; Tian, Pengyi; Wen, Shizhu; Guo, Fei; Hu, Yueqiang; Jia, Wenpeng; Dong, Conglin; Tian, Yu

2017-10-12

The coefficient of friction (COF) between two materials is usually believed to be an intrinsic property of the materials themselves. In this study, metals of stainless steel (304) and brass (H62), and polymers of polypropylene (PP) and polytetrafluoroethylene (PTFE) were tested on a standard ball-on-three-plates test machine. Significantly different tribological behaviors were observed when fixed and moving materials of tribo-pairs (metal/polymer) were switched. As an example, under the same applied load and rotating speed, the COF (0.49) between a rotating PP ball and three fixed H62 plates was approximately 2.3 times higher than that between switched materials of tribo-pairs. Meanwhile, the COF between H62 and PTFE was relatively stable. The unexpected tribological behaviors were ascribed to the thermal and mechanical properties of tribo-pairs. Theoretical analysis revealed that the differences in the maximum local temperature between switching the fixed and moving materials of tribo-pairs were consistent with the differences in the tested COF. This result indicated the precise prediction of the COF of two materials is complexcity, and that thermal and mechanical properties should be properly considered in designing tribo-pairs, because these properties may significantly affect tribological performance.

[Effects of combined application of water retention agent and organic fertilizer on physico-chemical properties of iron tailings.

PubMed

Li, Xiang; Zhang, Bao Juan; Li, Ji Quan; Li, Yu Ling; Li, Chen Guang

2017-02-01

In order to analyze the effects of combined application of water retention agent and orga-nic fertilizer on physico-chemical properties of iron tailings and to find the optimal proportion of water retention agent and organic fertilizer for the improvement of iron tailings, the experimental plots of the combination trials with 2 factors in 4 levels were designed in the iron tailings of Qian'an Shougang through investigating some indexes of physico-chemical properties such as bulk density, moisture capacity, porosity, pH and the contents of organic matter, nitrogen, phosphorus and potas-sium. The biomasses of Medicago sativa and Amorpha fruticosa planted in the experimental plots were measured to verify the improvement effects. 4 levels of super absorbent polymers (L·m -3 ) used in treatments were 0 (B 0 ), 10 (B 1 ), 50 (B 2 ), 100 (B 3 ), and 4 levels of organic fertilizer (kg·m -2 ) were 0(N 0 ), 2.25 (N 1 ), 11.24 (N 2 ), 22.49 (N 3 ). The improving effects of different treatments on physico-chemical properties of iron tailings were mainly reflected in the surface layer of 0-20 cm. All the tested indexes were significantly different from control (CK) in the layer of 0-20 cm. The improvement effects of organic fertilizer on physical and chemical properties of iron tai-lings were better than that of water retention agent. In the 0-20 cm layer, the bulk density, non-capillary porosity, organic matter, rapidly available phosphorus, and available potassium under all treatments of adding water retention agent individually were not significantly different from the CK, while significant difference was observed when the organic fertilizer was solely applied in B 0 N 2 and B 0 N 3 treatments. The improvement synergy effect of organic fertilizer and water retention agent was better than that of organic fertilizer or water retention agent, respectively. In 0-20 cm layer, all the indexes obtained from treatment B 3 N 3 performed best and were significantly different from the CK, which was the optimum for the improvement of iron tailings.

A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties.

PubMed

Joyce, Christopher; Burnett, Angus; Cochrane, Jodie; Reyes, Alvaro

2016-01-01

It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (M ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional (3D) trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60-67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties.

Morphological and physicochemical characterization of porous starches obtained from different botanical sources and amylolytic enzymes.

PubMed

Benavent-Gil, Yaiza; Rosell, Cristina M

2017-10-01

Porous starches might offer an attractive alternative as bio-adsorbents of a variety of compounds. However, morphology and physicochemical properties of starches must be understood before exploring their applications. Objective was to study the action of different amylolytic enzymes for producing porous starches. Wheat, rice, potato and cassava starches were treated with Amyloglucosidase (AMG), α-amylase (AM) and cyclodextrin-glycosyltransferase (CGTase). Morphological characteristics, chemical composition, adsorptive capacity and pasting/thermal properties were assessed. Scanning Electron Microscopy (SEM) showed porous structures with diverse pore size distribution, which was dependent on the enzyme type and starch source, but no differences were observed in the total granule surface occupied by pores. The adsorptive capacity analysis revealed that modified starches had high water absorptive capacity and showed different oil adsorptive capacity depending on the enzyme type. Amylose content analysis revealed different hydrolysis pattern of the amylases, suggesting that AMG mainly affected crystalline region meanwhile AM and CGTase attacked amorphous area. A heatmap illustrated the diverse pasting properties of the different porous starches, which also showed significant different thermal properties, with different behavior between cereal and tuber starches. Therefore, it is possible to modulate the properties of starches through the use of different enzymes. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of injection molding process windows for optical lenses using response surface methodology.

PubMed

Tsai, Kuo-Ming; Wang, He-Yi

2014-08-20

This study focuses on injection molding process window determination for obtaining optimal imaging optical properties, astigmatism, coma, and spherical aberration using plastic lenses. The Taguchi experimental method was first used to identify the optimized combination of parameters and significant factors affecting the imaging optical properties of the lens. Full factorial experiments were then implemented based on the significant factors to build the response surface models. The injection molding process windows for lenses with optimized optical properties were determined based on the surface models, and confirmation experiments were performed to verify their validity. The results indicated that the significant factors affecting the optical properties of lenses are mold temperature, melt temperature, and cooling time. According to experimental data for the significant factors, the oblique ovals for different optical properties on the injection molding process windows based on melt temperature and cooling time can be obtained using the curve fitting approach. The confirmation experiments revealed that the average errors for astigmatism, coma, and spherical aberration are 3.44%, 5.62%, and 5.69%, respectively. The results indicated that the process windows proposed are highly reliable.

Nanoparticle-Protein Interaction: The Significance and Role of Protein Corona.

PubMed

Ahsan, Saad Mohammad; Rao, Chintalagiri Mohan; Ahmad, Md Faiz

2018-01-01

The physico-chemical properties of nanoparticles, as characterized under idealized laboratory conditions, have been suggested to differ significantly when studied under complex physiological environments. A major reason for this variation has been the adsorption of biomolecules (mainly proteins) on the nanoparticle surface, constituting the so-called "biomolecular corona". The formation of biomolecular corona on the nanoparticle surface has been reported to influence various nanoparticle properties viz. cellular targeting, cellular interaction, in vivo clearance, toxicity, etc. Understanding the interaction of nanoparticles with proteins upon administration in vivo thus becomes important for the development of effective nanotechnology-based platforms for biomedical applications. In this chapter, we describe the formation of protein corona on nanoparticles and the differences arising in its composition due to variations in nanoparticle properties. Also discussed is the influence of protein corona on various nanoparticle activities.

Estimating Energy Conversion Efficiency of Thermoelectric Materials: Constant Property Versus Average Property Models

NASA Astrophysics Data System (ADS)

Armstrong, Hannah; Boese, Matthew; Carmichael, Cody; Dimich, Hannah; Seay, Dylan; Sheppard, Nathan; Beekman, Matt

2017-01-01

Maximum thermoelectric energy conversion efficiencies are calculated using the conventional "constant property" model and the recently proposed "cumulative/average property" model (Kim et al. in Proc Natl Acad Sci USA 112:8205, 2015) for 18 high-performance thermoelectric materials. We find that the constant property model generally predicts higher energy conversion efficiency for nearly all materials and temperature differences studied. Although significant deviations are observed in some cases, on average the constant property model predicts an efficiency that is a factor of 1.16 larger than that predicted by the average property model, with even lower deviations for temperature differences typical of energy harvesting applications. Based on our analysis, we conclude that the conventional dimensionless figure of merit ZT obtained from the constant property model, while not applicable for some materials with strongly temperature-dependent thermoelectric properties, remains a simple yet useful metric for initial evaluation and/or comparison of thermoelectric materials, provided the ZT at the average temperature of projected operation, not the peak ZT, is used.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions.

PubMed

Townsend, Catherine L; Laffy, Julie M J; Wu, Yu-Chang Bryan; Silva O'Hare, Joselli; Martin, Victoria; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K

2016-01-01

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions

PubMed Central

Townsend, Catherine L.; Laffy, Julie M. J.; Wu, Yu-Chang Bryan; Silva O’Hare, Joselli; Martin, Victoria; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K.

2016-01-01

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response. PMID:27729912

Discrepancies between Skinned Single Muscle Fibres and Whole Thigh Muscle Function Characteristics in Young and Elderly Human Subjects

PubMed Central

2016-01-01

We aimed to analyse the mechanical properties of skinned single muscle fibres derived from the vastus lateralis (VL) muscle in relation to those of the whole intact thigh muscle and to compare any difference between young and older adults. Sixteen young men (29.25 ± 4.65 years), 11 older men (71.45 ± 2.94 years), 11 young women (29.64 ± 4.88 years), and 7 older women (67.29 ± 1.70 years) were recruited. In vivo analyses were performed for mechanical properties such as isokinetic performance, isometric torque, and power. Specific force and maximum shortening velocity (Vo) were measured with single muscle fibres. Sex difference showed greater impact on the functional properties of both the whole muscle (p < 0.01) and single muscle fibres than aging (p < 0.05). Sex difference, rather than aging, yielded more remarkable differences in gross mechanical properties in the single muscle fibre study in which significant differences between young men and young women were found only in the cross-sectional area and Vo (p < 0.05). Age and sex differences reflect the mechanical properties of both single muscle fibres and whole thigh muscle, with the whole muscle yielding more prominent functional properties. PMID:28070513

Effect of hydrocolloids on the physico-chemical and rheological properties of reconstituted sweetened yoghurt powder.

PubMed

Seth, Dibyakanta; Mishra, Hari Niwas; Deka, Sankar Chandra

2018-03-01

The consistency of sweetened yoghurt (misti dahi) is a desired characteristic which is attributed to the casein protein network formation during fermentation. Unfortunately, this property is lost in reconstituted sweetened yoghurt (RSY) due to the irreversible nature of protein denaturation during spray drying. Therefore, this study aimed to increase the consistency of RSY using different hydrocolloids. The effects addition of guar gum, pectin, κ-carrageenan and gelatin (0.1%w/v each) on the physico-chemical, microbial, rheological and sensory properties of RSY were investigated. RSY with 40% total solids demonstrated the rheological properties which are very similar to those of fresh sweetened yoghurt. RSY containing different hydrocolloids further increased the rheological properties. The dynamic rheological study revealed that the magnitude of storage modulus (G'), loss modulus (G″), and loss tangent (tan δ) were significantly influenced by the addition of hydrocolloids and gelatin exhibited highest dynamic moduli in RSY. However, κ-carrageenan added RSY was preferred sensorially as the rheological properties were very close to gelatin added RSY. Addition of hydrocolloids significantly increased the starter bacteria count and pH and reduced water expulsion rate (P < 0.05). Addition of hydrocolloids can improve the rheological properties of reconstituted yoghurt. The study concluded that the addition of κ-carrageenan showed better results in terms of rheological and sensory properties of RSY. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The correlation between gelatin macroscale differences and nanoparticle properties: providing insight into biopolymer variability.

PubMed

Stevenson, André T; Jankus, Danny J; Tarshis, Max A; Whittington, Abby R

2018-05-21

From therapeutic delivery to sustainable packaging, manipulation of biopolymers into nanostructures imparts biocompatibility to numerous materials with minimal environmental pollution during processing. While biopolymers are appealing natural based materials, the lack of nanoparticle (NP) physicochemical consistency has decreased their nanoscale translation into actual products. Insights regarding the macroscale and nanoscale property variation of gelatin, one of the most common biopolymers already utilized in its bulk form, are presented. Novel correlations between macroscale and nanoscale properties were made by characterizing similar gelatin rigidities obtained from different manufacturers. Samples with significant differences in clarity, indicating sample purity, obtained the largest deviations in NP diameter. Furthermore, a statistically significant positive correlation between macroscale molecular weight dispersity and NP diameter was determined. New theoretical calculations proposing the limited number of gelatin chains that can aggregate and subsequently get crosslinked for NP formation were presented as one possible reason to substantiate the correlation analysis. NP charge and crosslinking extent were also related to diameter. Lower gelatin sample molecular weight dispersities produced statistically smaller average diameters (<75 nm), and higher average electrostatic charges (∼30 mV) and crosslinking extents (∼95%), which were independent of gelatin rigidity, conclusions not shown in the literature. This study demonstrates that the molecular weight composition of the starting material is one significant factor affecting gelatin nanoscale properties and must be characterized prior to NP preparation. Identifying gelatin macroscale and nanoscale correlations offers a route toward greater physicochemical property control and reproducibility of new NP formulations for translation to industry.

Photophysiological and light absorption properties of phytoplankton communities in the river-dominated margin of the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Chakraborty, Sumit; Lohrenz, Steven E.; Gundersen, Kjell

2017-06-01

Spatial and temporal variability in photophysiological properties of phytoplankton were examined in relationship to phytoplankton community composition in the river-dominated continental margin of the northern Gulf of Mexico (NGOM). Observations made during five research cruises in the NGOM included phytoplankton photosynthetic and optical properties and associated environmental conditions and phytoplankton community structure. Distinct patterns of spatial and temporal variability in photophysiological parameters were found for waters dominated by different phytoplankton groups. Photophysiological properties for locations associated with dominance by a particular group of phytoplankton showed evidence of photoacclimation as reflected by differences in light absorption and pigment characteristics in relationship to different light environments. The maximum rate of photosynthesis normalized to chlorophyll (PmaxB) was significantly higher for communities dominated (>60% biomass) by cyanobacteria + prochlorophyte (cyano + prochl). The initial slope of the photosynthesis-irradiance (P-E) curve normalized to chlorophyll (αB) was not clearly related to phytoplankton community structure and no significant differences were found in PmaxB and αB between different geographic regions. In contrast, maximum quantum yield of carbon fixation in photosynthesis (Φcmax) differed significantly between regions and was higher for diatom-dominated communities. Multiple linear regression models, specific for the different phytoplankton communities, using a combination of environmental and bio-optical proxies as predictor variables showed considerable promise for estimation of the photophysiological parameters on a regional scale. Such an approach may be utilized to develop size class-specific or phytoplankton group-specific primary productivity models for the NGOM.