Capillary Zone Research Articles

Analysis and Assessment of Behavior of Compacted Soils

Abstract: Most of the natural soils above ground water table (or above capillary zone) and invariably all the compacted soils in their placement condition are in the state of partial saturation. Unsaturated soils exist all over the world where the weather conditions are such that the annual evaporation potential is in excess of the precipitation. Unsaturated soils in their natural condition are generally found in tropical regions with arid and semi arid conditions. In such regions the soils are formed under peculiar hot and humid climate conditions and the soils so formed are subjected to seasonal moisture deficits. Hence the soils are in the state of partial saturation. All compacted soils in their placement water content are in state of partial saturation. The mechanical behaviour of unsaturated soils is strongly influenced by the presence of both the pore air and the pore water. The mechanisms governing the behaviour of unsaturated soils are quite different and need to be analyzed carefully as these soils are frequently encountered in engineering practice for founding many structures involving infrastructure development. The present investigation considers different soils representing wide spectrum of properties present in this region for probing the compaction and stress-strain characteristics. The soils are tested in quasi saturated state to circumvent the problems associated with the suction measurement and developing a phenomenological model for easy use by practicing engineers.

Protein Sulfhydryl Group Oxidation and Mixed-Disulfide Modifications in Stable and Unstable Human Carotid Plaques

Objectives. Oxidative stress has been implicated in the outcome of atherosclerotic plaques. However, at present, no data are available neither on the degree of plaque protein sulfhydryl groups oxidation nor on its relationship with plaque vulnerability. We investigated the entity of protein-SH oxidative modifications, focusing on low molecular weight thiols adduction, in human carotid plaque extracts in relation to plaque stability/instability. Methods. Plaque stability/instability was histologically assessed. The extent of protein-SH oxidative modifications was established by a differential proteomic approach on fluorescein-5-maleimide-labeled plaque extracts and corresponding plasma samples from 48 endarterectomized patients. The analysis on protein thiolation was performed by capillary zone electrophoresis. Results. We observed a higher protein-SH oxidation of both plasma-derived and topically expressed proteins in unstable plaques, partly due to higher levels of S-thiolation. Conversely, in plasma, none of the investigated parameters discriminated among patients with stable and unstable plaques. Conclusions. Our results suggest the presence of a more pronounced oxidative environment in unstable plaques. Identifying specific oxidative modifications and understanding their effects on protein function could provide further insight into the relevance of oxidative stress in atherosclerosis.

Diagnostic accuracy of electrophoretic analysis of native or defribrinated plasma using serum as a reference sample

Electrophoretic analysis of plasma may provide inaccurate results unless plasma is defibrinated with ethanol. The aim of this study, conducted following the Standards for Reporting of Diagnostic Accuracy (STARD), was to determine whether cellulose acetate (CAE), agarose gel (AGE), and capillary zone (CZE) electrophoresis of native plasma (NP) and defibrinated plasma (DP) provided the same information as serum electrophoretograms. Serum, NP, and DP electrophoretograms obtained using the 3 methods were examined visually by 3 observers to identify changes in globulin fractions and provide diagnostic interpretations. Using serum analysis as the reference method, sensitivity, specificity, and positive likelihood ratio of NP and DP electrophoretograms to identify abnormal globulin profiles were calculated. Specimens from 46 dogs were analyzed. Albumin and α(1) - and γ-globulin fractions were lower and β(2) -globulin fractions higher in NP than in serum and DP. Interpretations of NP electrophoretograms were the same as for serum in 54.8% (CAE), 51.2% (AGE), and 51.6% (CZE), revealed an increased β-globulin fraction in 32.3-41.5%, and resulted in misinterpretation, especially for CZE analysis, in 4.7-16.1% of the dogs; all dogs with abnormal serum electrophoretograms were identified correctly using NP. Analysis of DP was similar to serum analysis in about 2/3 of the dogs. In the others, defibrination did not resolve spurious plasma findings or induced additional changes. Up to 75 and 27% of NP and DP electrophoretograms, respectively, were abnormal in dogs with normal serum electrophoretograms. Sensitivity for NP and DP analysis was high, but specificity for NP was poor. Analysis of NP provides the same information as serum analysis in > 50% of cases, and, despite low specificity, could preliminarily exclude the presence of abnormalities when only plasma is available. If electrophoretograms are not normalized by defibrination, electrophoretic abnormalities are likely present, and electrophoresis should be repeated using serum.

Characteristics of moisture and salinity of soil in Taklimakan Desert, China

The Taklimakan desert is known as the largest dunefield in China and also as the world's second largest shifting sand desert. The Tarim Desert Highway, which is the first highway to cross the Taklimakan desert, was built for the purpose of oil and gas resources extraction in the Tarim area, as well as for the development of the southern area of the Xinjiang Uygur Autonomous Region. Shelterbelts have been planted along the highway to prevent shifting sand from burying the road. This paper analyzes the variations of moisture and salinity of the unirrigated desert soil under natural conditions in the center of Taklimakan Desert. A number of important findings indicating the moisture and salinity of the soil at capillary saturation zone were determined by the groundwater and related to the evaporation on the top. Salinity could be affected by vegetation, which was different from moisture in the soil. Meanwhile, clay layer played an important role in water preservation in the soil, which was also beneficial to the accumulation of salinity in soil. Compared with clay layer, vegetation was a decisive factor for the gathering of salinity. The findings were significant for reasonable adjustment of irrigation in the shelterbelts for the further development of the Tarim Desert Highway.

Determination of furosine in food products by capillary zone electrophoresis‐tandem mass spectrometry

A new method for qualitative and quantitative analysis of furosine in food products by capillary electrophoresis coupled to tandem mass spectrometry (CE-MS(2) ) has been optimized and validated. In analytical conditions, the pH value of the run buffer was similar to that of the hydrolyzed samples, which helps in avoiding interactions of the analyte with silanol groups of the inner wall of the fused silica capillary. In all previous CE methods proposed in literature, no SPE treatment has been used. The method has been applied to the analysis of food products, such as flour, having low amounts of furosine. Flour samples of different origin (wheat, chestnut, lupin, einkorn, chickpeas) have been investigated. Different food products such as pasta, milk, and tigelle bread (a typical Italian unleavened bread) were also analyzed. Some of the samples have also been analyzed by reversed-phase HPLC, and when compared to CE-MS, data obtained showed good agreement. CE-MS, in comparison to HPLC, showed advantages in terms of time of analysis and cost. The validation procedure provided good values for LOD and LOQ (respectively 0.07 and 0.25 mg L(-1) ), recovery (77 and 97%), and precision investigated in terms of intraday repeatability (RSD%: 4-6% for peak areas; 1-2% for migration times) and intermediate precision (below 16% for peak areas, and below 7% for migration times). Therefore, the technique reported can be proposed as a powerful analytical method and a valid alternative to common traditional analytical techniques.

Basal Ganglia Infarct in an Infant with Sickle Cell Disease – A Rare Association

Cerebrovascular accidents are common in elderly people, but rare in children. The stroke developing due to basal ganglion infarct in an infant with sickle cell disease (homozygous) is extremely rare. To the best of our knowledge, not a single case has been repoted till date. We are reporting a 10 months old infant developing stroke after a mild fall. The child was diagnosed of lacunar basal ganglion infarct in MRI. No abnormality was detected in routine hematological check-up and coagulation profile. But, sickling test was positive and confirmed of Sickle Cell Disease (SCD) in Hemoglobin electrophoresis (capillary zone). Although extremely rare, while dealing with stroke in infants and children, possibility of SCD should always be kept in mind.

Functional characterization and target discovery of glycoside hydrolases from the digestome of the lower termite Coptotermes gestroi.

BackgroundLignocellulosic materials have been moved towards the forefront of the biofuel industry as a sustainable resource. However, saccharification and the production of bioproducts derived from plant cell wall biomass are complex and lengthy processes. The understanding of termite gut biology and feeding strategies may improve the current state of biomass conversion technology and bioproduct production.ResultsThe study herein shows comprehensive functional characterization of crude body extracts from Coptotermes gestroi along with global proteomic analysis of the termite's digestome, targeting the identification of glycoside hydrolases and accessory proteins responsible for plant biomass conversion. The crude protein extract from C. gestroi was enzymatically efficient over a broad pH range on a series of natural polysaccharides, formed by glucose-, xylose-, mannan- and/or arabinose-containing polymers, linked by various types of glycosidic bonds, as well as ramification types. Our proteomic approach successfully identified a large number of relevant polypeptides in the C. gestroi digestome. A total of 55 different proteins were identified and classified into 29 CAZy families. Based on the total number of peptides identified, the majority of components found in the C. gestroi digestome were cellulose-degrading enzymes. Xylanolytic enzymes, mannan- hydrolytic enzymes, pectinases and starch-degrading and debranching enzymes were also identified. Our strategy enabled validation of liquid chromatography with tandem mass spectrometry recognized proteins, by enzymatic functional assays and by following the degradation products of specific 8-amino-1,3,6-pyrenetrisulfonic acid labeled oligosaccharides through capillary zone electrophoresis.ConclusionsHere we describe the first global study on the enzymatic repertoire involved in plant polysaccharide degradation by the lower termite C. gestroi. The biochemical characterization of whole body termite extracts evidenced their ability to cleave all types of glycosidic bonds present in plant polysaccharides. The comprehensive proteomic analysis, revealed a complete collection of hydrolytic enzymes including cellulases (GH1, GH3, GH5, GH7, GH9 and CBM 6), hemicellulases (GH2, GH10, GH11, GH16, GH43 and CBM 27) and pectinases (GH28 and GH29).

Distribution of Fuel‐Grade Ethanol near a Dynamic Water Table

Injections of fuel‐grade ethanol (95% v/v ethanol, 5% v/v hydrocarbon mixture as a denaturant) near the water table were conducted in two‐dimensional physical models tightly packed with fine sands under varying water‐table conditions. As the fuel migrated in the porous media following injection, the denaturant phase separated leaving a residual Light Non‐Aqueous Phase Liquid (LNAPL) phase that occupied a region with a volume similar to that of an equal‐sized spill of 100% LNAPL without ethanol. When the water table was raised, as may be expected following a catastrophic release that reaches groundwater, most of the ethanol‐fuel mixture was mobilized and the vertical distribution of the generated LNAPL was increased. The lower boundary of the residual LNAPL was established during the initial spreading of the fuel and did not change when the water table was raised or lowered. When the water table was raised in increments, the remaining concentrated ethanol/hydrocarbon mixture was mobilized and multiple relatively high LNAPL‐saturated lenses were observed in the capillary zone but within the initially LNAPL‐impacted zone. The distributions of ethanol and hydrocarbon components in this zone have direct implications for risk evaluation, monitoring strategies, and site management following releases of highly concentrated ethanol fuels.

Experimental and Modeling Investigation of Shallow Water Table Fluctuations in Relation to Reverse Wieringermeer Effect

Soil column experiments and modeling investigations were performed to study the behavior of shallow water table in response to various recharge events. Hence, shallow water table fluctuations inside sandy (Toyoura sand) and clayey (Chiba light clay) soil columns in response to surface and sub-surface recharge events were investigated under laboratory conditions. Experimental results showed that small application of water could raise the shallow water table level more than 100 times in depth in the case of Toyoura sand and more than 50 times in the case of Chiba LiC, reflecting a reverse Wieringermeer effect (RWE) response type of groundwater. This rise was associated with a prompt change of pressure head values which exhibited instantaneous fluctuations of centimeters due to the addition of millimeters of water. The recharge volumes leading to such disproportionate water table rise were successfully estimated using a simple analytical model based on the moisture retention curve of the soil and considering the hysteresis effect on soil water dynamics within the capillary fringe zone.

Review: Environmental tracers in arid-zone hydrology

Application of environmental tracers to arid-zone hydrology over the past several decades is reviewed, with particular reference to the Australian continent. Some notable successes in the application of stable and radio-isotopes include identifying arid-zone groundwater as palaeowaters, understanding the importance of episodicity and of large flood events to recharge, and delineating sources of water to vegetation. Estimating the rates of recharge and discharge have relied to a large extent on chloride and tritium profiles in the unsaturated zone, while radiocarbon and chlorine-36 are used to estimate horizontal flow rates. A number of new research opportunities are suggested. Improved understanding of processes that modify isotopic signatures at the interface zones such as the upper 5 m of the soil zone, the capillary zone, and the discharge zone, are needed to better quantify water fluxes across these zones. Furthermore, linkages between the atmosphere-soil-water-vegetation continuum although qualitatively understood, elude quantitative transfer to a scale commensurate with basin-scale groundwater management. The new generation of improved and more robust stable isotope and radiometric dating techniques, will be invaluable in advancing the science and its application to better management of meagre water resources in dry parts of the world.

Capillary Zone from a Watertable

An artificial perched watertable was constructed by a watertable construction machine at about 0.5 m depth from the soil surface in an area where the annual precipitation occurs only in the summer season to retain summer runoff in this watertable. The zone of capillary diffusion from the underground watertable during dry season for seven months from September to March in which no rain occurs was determined in an indoor soil bin which had a transparent side and a float and needle system to maintain water at a constant level. The results showed that water proceeded quickly into a whole sand layer and then into a clay soil layer. When the capillarity diffused into three-dimensional clay soil layer, the maximum length of the capillarity was 4.1 m in horizontal direction and the minimum length was 0.95 m in vertical direction for the seven months. Hence, the distance required to operate the watertable construction machine was 11.2 m.

Capillary Zone from a Watertable

Capillary Zone from a Watertable

The Decline of Soil Infiltration Capacity Due To High Elevation Groundwater

Infiltration capacity of soil mainly depends on two factors; the particle size and the moisture content of the soil. Groundwater increases the soil moisture, not only below the water table but also within the capillary zone, above the water table. Field experiment in a high groundwater area was conducted to understand the relationship among the groundwater, soil moisture and infiltration capacity. Using a single ring infiltrometer, the effect of groundwater in the infiltration rate was observed. This field experiment result shows that the groundwater influences significantly the infiltration capacity of the soil, and the infiltration rate follows a specific trendline.

Stable Hydrogen and Oxygen Isotope Composition of Waters from Mine Tailings in Different Climatic Environments

The stable isotope composition of waters (delta2H, delta18O) can be used as a natural tracer of hydrologic processes in systems affected by acid mine drainage. We investigated the delta2H and delta18O values of pore waters from four oxidizing sulfidic mine tailings impoundments in different climatic regions of Chile (Piuquenes at La Andina with Alpine climate, Cauquenes and Carén at El Teniente with Mediterranean climate, and Talabre at the Chuquicamata deposit with hyperarid climate). No clear relationship was found between altitude and isotopic composition. The observed displacement of the tailings pore waters from the local meteoric water line toward higher delta18O values (by approximately +2 per thousand delta18O relative to delta2H) is partly due to water-rock interaction processes, including hydration and O-isotope exchange with sulfates and Fe(III) oxyhydroxides produced by pyrite oxidation. In most tailings, from the saturated zone toward the surface, isotopically different zones can be distinguished. Zone I is characterized by an upward depletion of 2H and 18O in the pore waters from the saturated zone and the lowermost vadose zone, due to ascending diffused isotopically light water triggered by the constant loss of water vapor by evaporation at the surface. In zone II, the capillary flow of a mix of vapor and liquid water causes an evaporative isotopic enrichment in 2H and 18O. At the top of the tailings in dry climate a zone III between the capillary zone and the surface contains isotopically light diffused and atmospheric water vapor. In temperate climates, the upper part of the profile is affected by recent rainfall and zone III may not differ isotopically from zone II.

Fuel-grade ethanol transport and impacts to groundwater in a pilot-scale aquifer tank

Fuel-grade ethanol (76 L of E95, 95% v/v ethanol, 5% v/v hydrocarbon mixture as a denaturant) was released at the water table in an 8150-L continuous-flow tank packed with fine-grain masonry sand. Ethanol, which is buoyant and hygroscopic, quickly migrated upwards and spread laterally in the capillary zone. Horizontal migration of ethanol occurred through a shallow thin layer with minimal vertical dispersion, and was one order of magnitude slower than the preceding bromide tracer. Dyes, one hydrophobic (Sudan-IV) and one hydrophilic (Fluorescein) provided evidence that the fuel hydrocarbons phase separated from the E95 mixture as ethanol was diluted by pore water and its cosolvent effect was diminished. Most of the added ethanol (98%) was recovered in the effluent wells that captured the flow through the high water content regions above the water table. Complementary bench-scale 2-D visualization experiments with E95 confirmed hydrocarbon phase separation, residual NAPL formation and migration within the capillary fringe. These results corroborate previous bench-scale studies showing that ethanol has high affinity for vadose-zone pore water and can migrate through the capillary zone. The pilot-scale tank experiment provides the first hydrocarbon and ethanol concentration measurements (and thus, quantification of impacts to groundwater quality) from a subsurface spill of E95 in a well-characterized system with a well-defined source. It also provides the first quantitative near-field-scale evidence that capillarity can significantly retard the vertical dispersion and horizontal advection of ethanol. Such effects could be important determinants of the extent of ethanol migration and longevity as well as groundwater impacts.

Application of microfluidic chip with integrated optics for electrophoretic separations of proteins

This paper describes the fabrication, the characterization and the applications of a capillary electrophoresis microchip. This hybrid device (glass/PDMS) features channels and optical waveguides integrated in one common substrate. It can be used for electrophoretic separation and fluorimetric detection of molecules. The microfluidic performance of the device is demonstrated by capillary zone and gel electrophoresis of proteins.

Electrophoretic separation of tea flavanoids in the modes of capillary (zone) electrophoresis and micellar electrokinetic chromatography

Conditions for electrophoretic separation of tea phenolic enantiomers, (+)-catechin and (−)-epicatechin, by capillary (zone) electrophoresis using β-cyclodextrin as a component of the working electrolyte are developed. Optimization is made of the conditions for separating a multicomponent mixture of ionic and neutral polyphenols from various tea samples in the mode of micellar electrophoretic chromatography using sodium dodecyl sulfate as a micelle-forming agent and urea as an additive to the phosphate buffer.

English

A promising concept, known as the elevated water table, is emerging as a management and possible closure technique to limit AMD production from tailings impoundments. This prevention approach is based on the principle that tailings in the capillary zone can be maintained in a state close to full saturation which minimizes oxygen diffusion and thus limits acid generation. A parametric study was conducted to evaluate the effect of various factors on the water content profiles in reactive tailings. The results presented here show that the position of the water table has a large influence on the water content profiles and on the oxygen flux at the tailings surface. For a water table depth value smaller or equal to the tailings' air entry value (a), the degree of saturation Sr varies between 90 to 99 % at the tailings surface, covered by a sand protection layer. These high Sr values yield effective diffusion coefficient De comparable to that of O2 diffusion in water. The study also shows that the efficiency of the elevated water table concept can be negatively affected when the tailings are highly reactive.

Glycoprotein Characterization Combining Intact Protein and Glycan Analysis by Capillary Electrophoresis-Electrospray Ionization-Mass Spectrometry

Glycosylated proteins play important roles in a large number of biological processes. Therefore, a complete characterization in terms of glycan structures and glycoform heterogeneity is needed. In this paper, a combined approach based on glycan and intact glycoprotein analysis by capillary zone electrophoresis-electrospray-mass spectrometry (CZE-ESI-MS) is presented. Based on a new capillary coating, a CZE-ESI-MS method for the separation and characterization of intact glycoproteins has been developed and compared to a method recently introduced for the characterization of erythropoietin. The excellent glycoform separation results in high-quality mass spectra, high dynamic range, and good sensitivity, allowing the correct characterization of minor glycan modifications. Additionally, a CZE-ESI-MS separation method for underivatized N-glycans has been developed. The separation of glycans differing in the degree of sialic acids and repeats of noncharged carbohydrates is achieved. The separation power of the method is demonstrated by obtaining mobility differences in glycans differing only by 16 Da. A time-of-flight mass spectrometer allowed the correct identification of the glycan composition based on high mass accuracy and resolution, identifying even minor modifications such as the exchange of "O" by "NH". An ion trap mass spectrometer provided structural information of the underivatized glycans from fragmentation spectra. The general applicability of both methods to glycoprotein analysis is illustrated for erythropoietin, fetuin, and alpha1-acid glycoprotein. The results obtained by the glycan analysis allowed an unequivocal glyco-assignment to the masses obtained for the intact proteins as long as the protein backbone is well characterized. Furthermore, modifications found for intact proteins can be attributed to differences in the glycostructure.

Detection and identification of low-concentration M proteins with CZE/IS; a 'dry' analysis

The accuracy of detection and identification of low-concentration M proteins using capillary zone electrophoresis/immunosubtraction (CZE/IS) plots was systematically studied. To this end, 49 CZE plots (protein spectra; session I) and CZE/IS plots (spectra with corresponding immunosubtraction plots; session II) were judged by participants from 12 Dutch laboratories. Plots were based on mixed sera with a low concentration (0.4, 1 or 4 g/L) of one M protein, as well as normal sera, sera with an oligoclonal or polyclonal increase in immunoglobulins, and sera containing free monoclonal light chains. At 0.4 g/L, nine out of 12 (9/12) different M proteins were hard to detect. At 1 g/L, 6/12 M proteins were detected by > 85% of the participants. At 4 g/L, 10/12 M proteins were detected by all participants. Normal spectra were always judged correctly. At 1 g/L and 4 g/L, detected M proteins were identified correctly by 92% of the participants, versus only 63% at 0.4 g/L. The detection accuracy was only slightly (non-significantly) improved by the application of IS plots. Our data indicate that CZE/IS is applicable for most M proteins at concentrations > or = 4 g/L.