Influx Rate Research Articles

Finite volume simulation of calcium distribution in a cholangiocyte cell

Cholangiocytes are the cells of the liver having a major role in the conditioning of bile used in digestion. Other functions of cholangiocytes are in apoptosis and bicarbonate secretion. The Calcium in the intracellular environment of various cells including cholangiocytes regulates a large number of functions. This regulating mechanism in cholangiocytes has been poorly understood to date. In order to analyze the calcium regulation in cholangiocyte cells, a mathematical model for a one-dimensional steady-state case is constructed in this study. This involves a non-linear reaction-diffusion equation with appropriate boundary conditions. The influx from IP$_{3}$ receptor, ryanodine receptor (RYR), and plasma membrane as well as the efflux of calcium from SERCA pump and plasma membrane have been employed in the model. The finite volume method and Newton-Raphson method have been used to solve the problem. Numerical findings have been used to examine the effects of parameters like diffusion coefficient, rate of SERCA pump efflux, buffer, and influx from plasma membrane on calcium concentration in cholangiocyte cells. The information generated from the model can be useful for understanding the mechanism of cholestatic disorders which can be further useful in the diagnosis and treatment of these disorders.

Расчетные параметры функционального зонирования озелененной территории центральной части города Реутова

Introduction. The article devoted to the relevant problem of optimizing the natural framework of the city on the basis of rational use of the territory of the settlement as a public green area. The approach, based on the modern tendencies of urbanization, ecological utility, social benefits and rational use of territories. One of the important elements of the optimization of the ecological environment is the greening of the city space. At present, maintaining the balance of urbanized areas is a priority because with the growth and development of cities, the environment is becoming more and more aggressive. Also, with the increase in the number of residents, the recreational load increases, and due to the high concentration of emissions from motor vehicles and industrial enterprises, the state of urban natural systems is changing, which leads to a deterioration in the quality of life of the population. The system of green spaces of a modern city is being formed to improve the environment, enrich the appearance of the city, create conditions for mass recreation of the population in the natural environment. For the formation of the ecological situation in the city, along with cardinal measures, it is necessary to preserve and develop natural massifs and landscaping of the city territory. The article analyzes the relevant planning opportunities and constraints for urban transformation of the city, and also selects the optimal strategy for spatial development of the reorganization of the natural framework. Materials and methods. The collected attributive information, legal documents and cartographic materials are used in the work. The calculation of potential visitors was carried out on the basis of the normative value for recreational load, and the calculation of visitors to the natural-anthropogenic territorial complex (hereafter — NATC) was carried out by means of field observation. The observation results were processed using the Microsoft Office Excel software, followed by modelling of the project proposal for the use of the Reutov green space in the Qgis software package. Results. On the basis of the conducted research, the excess of the normative value of recreational load of the NATC “Apple Orchard” in Reutov was identified and a functional zoning project, including the design of three functional zones, was proposed. Conclusions. The increased rate of population influx and environmental pollution is forcing a reorganization of the green cores of cities.

Physiological and life history responses in a mayfly (Callibaetis floridanus) inhabiting ponds with saltwater intrusion

Freshwater salinity varies in natural systems and plays a role in species distribution. Anthropogenic alterations to freshwater salinity regimes include sea level rise and subsequent intrusion of saline waters to inland habitats. While mayflies are generalized to be sensitive to increasing salinity, we still know remarkably little about the physiological processes (and their plasticity) that determine the performance of species in a changing world. Here, we explored life-history outcomes and physiological plasticity in a population of Callibaetis floridanus (Ephemeroptera: Baetidae) from a coastal pond that routinely experiences saltwater intrusion. We reared naiads from egg hatch to adulthood across a gradient of increasing salinities (113, 5,020, 9,921 μS/cm). Radiotracer flux studies (22Na, 35SO4, and 45Ca) were conducted in naiads reared at each salinity, revealing a positive association between ionic concentration and uptake rates. However, the influence of rearing history on ionic influx rates was apparent when naiads were transferred from their respective rearing water to the other experimental conditions. For example, we observed that naiads reared in the low salinity treatment (113 μS/cm) had 10.8-fold higher Na uptake rates than naiads reared at 9,921 μS/cm and transferred to 113 μS/cm. Additionally, naiads acclimated to the higher salinity water exhibited reduced uptake in ion-rich water relative to those reared in more dilute conditions (e.g., in 9,921 μS/cm water, 113 and 5,020 μS/cm acclimated naiads had 1.5- and 1.1-fold higher Na uptake rates than 9,921 μS/cm acclimated naiads, respectively). We found no significant changes in survival (80 ± 4.4%, mean ± s.e.m.) or naiad development time (24 ± 0.3 days, mean ± s.e.m.) across these treatments but did observe a 27% decrease in subimago female body weight in the most dilute condition. This reduction in female weight was associated with higher oxygen consumption rates in naiads relative to the other rearing conditions. Collectively, these data suggests that saline adapted C. floridanus may be more energetically challenged in dilute conditions, which differs from previous observations in other mayfly species.

Dynamics of soil bio-physicochemical properties under different disturbance regimes in sal forests in western Himalaya, India

Disturbance is a key factor in controlling vegetation diversity, nutrient influx rate, and biochemical cycling in terrestrial forest ecosystems. Limited studies are available on changes in tree diversity, soil nutrients and enzyme activities in response to different intensities of land disturbances in the Himalayan forests. Present study investigated the impact of varying intensities of disturbances on tree diversity and their relationship with soil physical and bio-chemical properties in sal forests, Western Himalayas. Sites were categorized into four different classes of disturbances, namely, No disturbance (ND), Low disturbance (LD), Moderate disturbance (MD), and High disturbance (HD). Composite samples were collected at two depths (0–15 and 15–30 cm) in each plot to investigate soil physical and biochemical properties. Multivariate analyses were conducted to find relationship between tree vegetation and soil physical and biochemical properties. Soil organic carbon (Corg), total nitrogen (Nttl), available phosphorous (Pavl), microbial biomass carbon (Cmic), nitrogen (Nmic), phosphorous (Pmic), and enzymes (dehydrogenase (DHA), Urease, acid and alkaline phosphatase) followed the order: MD > ND > LD > HD. Across disturbances, soil physical and biochemical characteristics significantly (p < 0.05) decreased with increasing soil depths. Across the sites, positive correlation was observed among soil microbial biomass, enzymes, Corg, clay, and moisture. Redundancy analysis (RDA) results revealed that species distribution is essential regulator in the variation of prominent soil variables, viz., nutrients (Nttl and Pavl), Cmic, and DHA across disturbance categories and soil depths. Moreover, variance partitioning analysis (VPA) showed that changes in vegetation composition across disturbance levels explain 13.12 % of the variation in soil biochemical subset higher than soil physicochemical subset. The result illustrated that moderate disturbance increases species composition, soil nutrient properties and microbial activity. These findings would help understand microbial activity and its relationship with disturbances, suggesting site-specific measurements for soil nutrient availability and above-below ground interactions.

A Novel Data Assimilation-Based Real-Time State Estimation Method for Gas Influx Profiling During Riser Gas Events

AbstractRiser gas events during offshore drilling operations are hazardous and challenging to control. Therefore, knowledge of the gas influx sizes and distributions in a marine drilling riser is critical for the selection of riser gas handling methods and the estimation of risks of riser gas unloading. An extended Kalman filter-based data assimilation method is developed and evaluated for the real-time estimation of gas influx rates and void fraction distributions in a riser during riser gas handling. Full-scale experiments were conducted in this study for the evaluation of the proposed data assimilation method. An offshore well, which consists of a marine drilling riser and a wellbore below the subsea blowout preventer, was simulated by a 1572-m-deep experimental well. Real-time measurement data, including surface and downhole pressures, pump rates, and liquid outflow rates, were used to estimate the downhole gas influx rates using the Kalman filter. An online calibrated drift-flux model based on data assimilation is used to estimate the distributions of void fractions in the riser over time. The measurement data from a gas flowmeter and the distributed fiber-optic sensing were used to validate the estimation results, and satisfying performance was seen from the presented method. This study proposed a novel data assimilation-based state estimation method by maximizing the use of measurement data of different types from the available managed pressure drilling systems. This method enables the more accurate estimation and prediction of gas behaviors in a riser and helps to facilitate real-time decision-making during riser gas handling.

Validation of simplified uptake measures against dynamic Patlak Ki for quantification of lesional 89Zr-Immuno-PET antibody uptake

PurposePositron emission tomography imaging of zirconium-89-labelled monoclonal antibodies (89Zr-Immuno-PET) allows for visualisation and quantification of antibody uptake in tumours in vivo. Patlak linearization provides distribution volume (VT) and nett influx rate (Ki) values, representing reversible and irreversible uptake, respectively. Standardised uptake value (SUV) and tumour-to-plasma/tumour-to-blood ratio (TPR/TBR) are often used, but their validity depends on the comparability of plasma kinetics and clearances. This study assesses the validity of SUV, TPR and TBR against Patlak Ki for quantifying irreversible 89Zr-Immuno-PET uptake in tumours.MethodsTen patients received 37 MBq 10 mg 89Zr-anti-EGFR with 500 mg/m2 unlabelled mAbs. Five patients received two doses of 37 MBq 89Zr-anti-HER3: 8–24 mg for the first administration and 24 mg–30 mg/kg for the second. Seven tumours from four patients showed 89Zr-anti-EGFR uptake, and 18 tumours from five patients showed 89Zr-anti-HER3 uptake. SUVpeak, TPRpeak and TBRpeak values were obtained from one to six days p.i. Patlak linearization was applied to tumour time activity curves and plasma samples to obtain Ki.ResultsFor 89Zr-anti-EGFR, there was a small variability along the linear regression line between SUV (− 0.51–0.57), TPR (− 0.06‒0.11) and TBR (− 0.13‒0.16) on day 6 versus Ki. Similar doses of 89Zr-anti-HER3 showed similar variability for SUV (− 1.3‒1.0), TPR (− 1.1‒0.53) and TBR (− 1.5‒0.72) on day 5 versus Ki. However, for the second administration of 89Zr-anti-HER3 with a large variability in administered mass doses, SUV showed a larger variability (− 1.4‒2.3) along the regression line with Ki, which improved when using TPR (− 0.38–0.32) or TBR (− 0.56‒0.46).ConclusionSUV, TPR and TBR at late time points were valid for quantifying irreversible lesional 89Zr-Immuno-PET uptake when constant mass doses were administered. However, for variable mass doses, only TPR and TBR provided reliable values for irreversible uptake, but not SUV, because SUV does not take patient and mass dose-specific plasma clearance into account.

Drought priming mechanisms in wheat elucidated by in-situ determination of dynamic stomatal behavior.

Stomata play a critical role in balancing photosynthesis and transpiration, which are essential processes for plant growth, especially in response to abiotic stress. Drought priming has been shown to improve drought tolerance. Lots of studies have been done with the response of stomatal behavior to drought stress. However, how the stomatal dynamic movement in intact wheat plants response to drought priming process is not known. Here, a portable microscope was used to take microphotographs in order to in-stiu determination of stomatal behavior. Non-invasive micro-test technology was used for measurements of guard cell K+, H+ and Ca2+ fluxes. Surprisingly, the results found that primed plants close stomatal much faster under drought stress, and reopening the stomatal much quicker under recovery, in relation to non-primed plants. Compared with non-primed plants, primed plants showed higher accumulation of ABA and Ca2+ influx rate in guard cells under drought stress. Furthermore, genes encoding anion channels were higher expressed and K+ outward channels activated, leading to enhanced K+ efflux, resulting in faster stomatal closure in primed plants than non-primed plants. During recovery, both guard cell ABA and Ca2+ influx of primed plants were found to be significantly reducing K+ efflux and accelerating stomatal reopening. Collectively, a portable non-invasive stomatal observation of wheat found that priming promoted faster stomatal closure under drought stress and faster reopening during post-drought recovery in relation to non-primed plants, thereby enhancing overall drought tolerance.

OxLDL-Induced Foam Cell Formation Inhibitory Activity of Pepsin Hydrolysate of Ark Shell (Scapharca subcrenata (Lischke, 1869)) in RAW264.7 Macrophages

Inhibitory effect of ark shell (Scapharca subcrenata (Lischke, 1869)) proteolytic hydrolysates (ASHs) on oxidized low-density lipoprotein (oxLDL)-induced macrophage foam cell formation was investigated. Two types of ASHs were prepared by Alcalase® and pepsin, ASAH (ark shell-Alcalase® hydrolysates), and ASPH (ark shell-pepsin hydrolysate). Oil Red O staining results showed that ASPH suppressed foam cell formation and lipid accumulation more than ASAH in oxLDL-induced foam cell formation of RAW264.7 macrophages. ASPH reduced the levels of total cholesterol, cholesterol ester, and free cholesterol in oxLDL-treated RAW264.7 macrophages. It was found that ASPH increased cholesterol efflux and decreased cholesterol influx rate. In this regard, protein expressions of CD36 and scavenger receptor class A1 (SR-A1) for cholesterol influx and ATP-binding cassette transporter A1 and G1 (ABCA1 and ABCG1) for cholesterol efflux were investigated. ASPH treatment resulted in an increase of ABCA1 and ABCG1 expression but downregulated CD36 and SR-A1 expression. Furthermore, ASPH suppressed production of proinflammatory cytokines, including tumor necrosis factor-α and interleukin-6 and -1β, through regulating nuclear factor-kappa B (NF-κB) in oxLDL-induced foam cell formation of RAW264.7 macrophages. Taken together, our data indicate that ASPH might be a useful ingredient in functional foods for ameliorating atherosclerosis by preventing foam cell formation.

Hypothermia impairs glymphatic drainage in traumatic brain injury as assessed by dynamic contrast-enhanced MRI with intrathecal contrast.

The impact of hypothermia on the impaired drainage function of the glymphatic system in traumatic brain injury (TBI) is not understood. Male Sprague-Dawley rats undergoing controlled cortical impact injury (CCI) were subjected to hypothermia or normothermia treatment. The rats undergoing sham surgery without CCI were used as the control. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with intrathecal administration of low- and high-molecular-weight contrast agents (Gd-DTPA and hyaluronic acid conjugated Gd-DTPA) was performed after TBI and head temperature management. The semiquantitative kinetic parameters characterizing the contrast infusion and cleanout in the brain, including influx rate, efflux rate, and clearance duration, were calculated from the average time-intensity curves. The qualitative and semiquantitative results of DCE-MRI obtained from all examined perivascular spaces and most brain tissue regions showed a significantly increased influx rate and efflux rate and decreased clearance duration among all TBI animals, demonstrating a significant impairment of glymphatic drainage function. This glymphatic drainage dysfunction was exacerbated when additional hypothermia was applied. The early glymphatic drainage reduction induced by TBI and aggravated by hypothermia was linearly related to the late increased deposition of p-tau and beta-amyloid revealed by histopathologic and biochemical analysis and cognitive impairment assessed by the Barnes maze and novel object recognition test. The glymphatic system dysfunction induced by hypothermia may be an indirect alternative pathophysiological factor indicating injury to the brain after TBI. Longitudinal studies and targeted glymphatic dysfunction management are recommended to explore the potential effect of hypothermia in TBI.

Single-cell clinical chemistry: Exploring glucose uptake kinetics and HbA1c levels in individual red blood cells.

Single-molecule techniques have been a primary focus of many advances in biophysics over the last decades. However, the fact that many related technologies such as microfluidics, confocal microscopy, etc. are becoming standard laboratory tools makes it possible to pursue other goals such as single cell measurements. If single molecules are the building blocks of matter, single cells are the building blocks of biology, and the individual detection thereof offers similar benefits. Currently, most blood work is cuvette-based, averaging tens of millions of blood cells to obtain a single ensemble value. Measuring single blood cells yields a distribution of values, which provides more information about a given patient as well as how that patient may differ from the general populace. All of which is important in an era of big data which increasingly inclines medicine towards a more personalized approach. Our work focuses on the relationship between glucose, red blood cells (RBCs) and glycated hemoglobin, as quantifying the interplay of these parameters is important for a better understanding of diabetes. Using a microfluidic perfusion system allows the placement of RBCs and control over the solutions to which they are exposed. Using confocal microscopy and image analysis, we are able to observe the kinetics of fluorescently-labeled glucose passing into and out of individual RBCs and extract the relevant information, such as glucose influx and efflux rates, intracellular vs blood glucose levels, and more. Overall, we seek to quantify the relationship between bloodstream and intracellular glucose levels to inform a more personalized, and perhaps improved, diagnostic strategy for diabetes. We are also currently developing methods for quantifying %HbA1c at the single cell level utilizing Raman microscopy and mass spectrometry.

Formation of Ultra‐Depleted Mantle Peridotites and Their Relationship With Boninitic Melts: An Example From the Kamuikotan Unit, Hokkaido, Japan

AbstractThe extent of partial melting of peridotites is a function of temperature, pressure, and fluid supply. Understanding the petrogenesis of ultra‐depleted peridotites is important for elucidating mantle potential temperature and the role of water in the mantle. We analyzed the major and trace element compositions of ultra‐depleted peridotites from the Kamuikotan zone, Japan. Geochemical models were then generated to constrain the melting conditions and their relation to boninitic melts. The peridotites are characterized by minerals with high Mg/Fe and Cr/Al ratios, and olivine and orthopyroxene with low Ti and Y contents. The mineral compositions suggest that these peridotites are among the most depleted peridotites on Earth. Orthopyroxene compositions characterized by Zr and Sr enrichments relative to Ti and Y depletion cannot be solely explained by melt extraction from typical mantle compositions. Modeling of influx melting reproduces orthopyroxene trace element compositions of ultra‐depleted harzburgites formed after high degrees (&gt;30%) of slab‐fluid influx melting at a low influx rate and melt fraction. The instantaneous fractional melts equilibrated with residues produced by the melting model and the melts, which equilibrated with amphiboles have similar trace elements patterns as boninites. However, the instantaneous fractional melts have low trace element abundances indicating that ultra‐depleted harzburgites are residues after extraction of refractory melts. Boninites are probably accumulated melts formed during the melting processes, or fractionated melt from the instantaneous fractional melts. High temperatures (&gt;1350°C) and continuous fluid supply are key to the formation of ultra‐depleted peridotites and boninites during subduction initiation.

Sly-miR398 Participates in Cadmium Stress Acclimation by Regulating Antioxidant System and Cadmium Transport in Tomato (Solanum lycopersicum).

Cadmium (Cd) pollution is one of the major threats in agricultural production, and can cause oxidative damage and growth limitation in plants. MicroRNA398 (miR398) is involved in plant resistance to different stresses, and the post-transcriptional regulation of miR398 on CSDs plays a key role. Here, we report that miR398 was down-regulated in tomato in response to Cd stress. Simultaneously, CSD1 and SOD were up-regulated, with CSD2 unchanged, suggesting CSD1 is involved in miR398-induced regulation under Cd stress. In addition, the role of miR398 in Cd tolerance in tomato was evaluated using a transgenic line overexpressing MIR398 (miR398#OE) in which the down-expression of miR398 was disrupted. The results showed that Cd stress induced more significant growth inhibition, oxidative damage, and antioxidant enzymes disorder in miR398#OE than that in wild type (WT). Moreover, higher Cd concentration in the shoot and xylem sap, and net Cd influx rate, were observed in miR398#OE, which could be due to the increased Cd uptake genes (IRT1, IRT2, and NRAMP2) and decreased Cd compartmentalization gene HMA3. Overall, our results indicate that down-regulated miR398 plays a protective role in tomato against Cd stress by modulating the activity of antioxidant enzymes and Cd uptake and translocation.

Noninvasive micro-test technology: monitoring ion and molecular flow in plants.

Noninvasive micro-test technology (NMT) is a novel technology to investigate the influx and/or efflux rate, direction, and concentration of selected ions and molecules in a microenvironment surrounding living cells or intact organisms. NMT measures and records the spatial electric potential differences in liquid media-surrounded living cells, tissues, and small organisms. Measurements are taken by a vibrating selective and/or specific flux sensor, combined with computerized algorithm to reveal ionic or molecular exchanges in the microenvironment with high sensitivity.

Влияние лесоводственных мероприятий на почвенный углерод: обзор

The paper provides a review of Russian and foreign articles regarding studying the impact of silvicultural practices on the soil carbon pool to assess the effectiveness of forest carbon projects. Analyzing the works allowed us to conclude that silvicultural practices affect the content of soil carbon through a change in the rate of influx and decomposition of organic matter and, as a result, affect the redistribution of carbon in the soil profile. High-intensity felling, including clear felling, removal of logging residues, damage to the ground cover when planting forest crops, and the development of monocultures can negatively affect the soil carbon pool. On the contrary, selective and low-intensity thinning, leaving logging residues, and planting mixed forest stands, especially on abandoned agricultural lands, proved to be promising forest management practices that contribute to the accumulation and conservation of soil carbon.

The valuable role of dynamic 18F FDG PET/CT-derived kinetic parameter [formula omitted] in patients with nasopharyngeal carcinoma prior to radiotherapy: A prospective study

Background and PurposeDynamic positron emission tomography/computed tomography (PET/CT) served the potential role of characterizing malignant foci. The main objective of this prospective study was to explore the advantage of dynamic PET/CT imaging in characterizing nasopharyngeal carcinoma (NPC). Methods and MaterialsPatients with probable head and neck disease underwent a local dynamic PET/CT scan followed by a whole-body static scan. Patlak analysis was used to generate parametric influx rate constant (Ki) images from 48 frames obtained from a dynamic PET/CT scan. By delineating the volumes-of-interest (VOIs) of: primary tumor (PT), lymph node (LN), and normal nasopharyngeal tissues (N), we acquired the corresponding Ki mean and SUVmean of each site respectively to perform the quantitative statistical analysis. ResultsQualified images of 71 patients with newly diagnosed NPC and 8 without nasopharyngeal malignant lesions were finally included. We found the correlations between Ki mean-PT and critical clinical features, including clinical stage (r = 0.368), T category (r = 0.643) and EBV-DNA copy status (r = 0.351), and Ki mean-PT differed within the group. SUVmean-PT showed correlations with clinical stage (r = 0.280) and T category (r = 0.472), but could hardly differ systematically within group of clinical features except T category. Ki mean-LN offered the positive correlations with N category (r = 0.294), M category (r = 0.238) and EBV-DNA copy status (r = 0.446), and differed within the group. In addition, Ki mean represented a sensitivity of 94.4 % and a specificity of 100 %, in distinguishing NPC from the non-NPC, when the cut-off was defined as 0.0106. When the cut-off of SUV being defined as 2.03, the sensitivity and specificity were both 100 %. ConclusionOur research confirmed Ki compared favorably to SUV in characterizing NPC and found that Ki can serve as an effective imaging marker of NPC.

Changes in phosphorus turnover when soils under long-term P management are amended with bio-based fertiliser

Understanding available phosphorus (P) turnover could improve sustainable P management. An isotope tracing 33P was used to measure daily P turnover rates and exchangeable P (E) in P deficient, balanced, and excess P soils from a long-term P site. Turnover under P deficient conditions was characterised by the lowest P flux predominantly from the available into the exchangeable P pools (P efflux). The P efflux in the P deficient soil was 3.7 ± 0.6 mg P/L day−1 and the inverse flux (P influx) was 1.6 ± 0.4 mg P/L day−1. Turnover rates were more than twofold higher under P balanced and surplus conditions, exhibiting an equilibrium between influx and efflux rates. The contribution of abiotic processes to P turnover was predominant in the excess P soil, whereas biotic processes dominated turnover rates under P deficient conditions.Changes in P turnover were measured following application of single superphosphate (SSP) and dairy processing sludge (DPS). Both fertiliser types increased P turnover rates and availability across all soils. After SSP application, E values plateaued between 238 and 297 mg P/L regardless of initial P status. Slower P release from DPS was evidenced by a wider range of E values (97–160 mg P/L) with slower turnover.

Differential sedimentary mechanisms of Upper Ordovician-Lower Silurian shale in southern Sichuan Basin, China

The Wufeng-Longmaxi Formations are the focus of shale gas exploration in China. Their sedimentation is affected by global and regional geological events, and the resulting heterogeneity hinders the expansion of exploration results. This study combines logging, mineralogy, and geochemistry to reconstruct the sedimentary mechanisms of shale in the southern Sichuan Basin and discusses its implications for exploration. The shale can be divided into third-order sequences, in which the Wufeng Formation and lower Long-1 Member are transgressive systems tracts (TST1 and TST2), and the Guanyinqiao Member and the middle-upper Long-1 Member are highstand systems tracts (HST1 and HST2). Volcanic eruption and glaciation evolution are the driving factors of the sedimentary environment during the TST. The area is in a cold-warm climate, characterized by anoxic conditions, slow sedimentation, booming productivity, and low terrigenous influx, thereby depositing four types of siliceous shale. The siliceous shale is rich in biogenic microcrystalline quartz and high TOC, which are the keys to becoming the “sweet spot” of shale gas. Microcrystalline quartz fills the intergranular pores to support the entire pore network framework. The organic matter undergoes thermal evolution to produce abundant organic matter pores, which constitute the main place for adsorbed gas and free gas. For the highstand systems tract, HST1 is the product of the peak of glaciation, mainly composed of calcareous shale and carbonate rocks. The sedimentation of HST2 is affected by turbidity currents and violent orogeny. The area is in a warm climate, characterized by high terrigenous influx, dysoxic-oxic conditions, medium productivity and rapid sedimentation rates. The lithofacies gradually changed from siliceous shale to mixed shale and argillaceous shale. Excessive clay minerals and low TOC make it difficult for HST2 to realize the commercial development of shale gas.

Net Ecosystem Exchange of Carbon Dioxide in Rice Summer – Autumn crop of the lower Mekong delta, Vietnam

This study describes the net ecosystem exchange of CO2 in a rice summer-autumn growth season in the lower Mekong Delta, Vietnam. Eddy Covariance and bio-meteorological systems were used to continually record the net CO2 exchange between the paddy field and the atmosphere, together with environmental variables affecting the exchange rate. Rice plant growth (height, above-, and belowground biomass) was measured every 15 days during the entire crop. Our study paddy field emitted CO2 at the mean rate of 5.06 ± 2.49 µmol m-2 s-1, while the rate of CO2 capturing was 18.65 ± 11.76 µmol m-2 s-1 throughout the entire crop. The paddy field acted as a CO2 sink almost during the crop. The quick increase of leaf area from the 15th to the 60th day led to the rise in CO2 influx. The decrease in influx rate after the 60th day resulted from the senescence and death of the aboveground biomass. The drainage in the last ten days of the crop probably contributed to the increase in CO2 effluxes and hence, turned the paddy field into a CO2 source. Ambient temperature was an important factor affecting the rate of CO2 exchange affects the photosynthesis, plant respiration, photorespiration, and organic matter decomposition.

One-dimensional numerical model for unsteady solute transport in open channels under multi-point loading

A numerical method for solving the unsteady-one-dimensional advection-dispersion equation for solute transport in streams and channels imposed with multiple point-loading is presented. The numerical technique proposes to solve the equation, which also includes a first-order decay term and a loading term, using techniques similar to those employed by the finite volume method (FVM). The channel length is segmented into cells and the solution aims at evaluating the concentrations at the cell interfaces or the internal nodes, at prescribed time steps for the steady condition of the flow. The results are computed commencing from a specified time level with known spatial concentration within the domain. It is assumed that the boundary nodes at the two ends of the channel, one each at the upstream and the downstream, are specified with solute concentration values or its spatial gradient at all times. Unlike the standard within-the-cell spatial approximations of a variable assumed in the finite volume or finite element schemes, the proposed method models the spatial variation of the solute concentration within a cell by an analytical expression in terms of the concentrations at the two boundary nodes of the cell and the influx rate of point-loading, if any, located within the cell. Using such a closed-form function based upon the true nature of the problem not only helps in capturing the spatial variation of concentration within a cell more precisely but also allows a better approximation of its spatial gradients at the cell interfaces, thus helping to achieve a more accurate computation of the inter-cell dispersive fluxes. The performance of the proposed algorithm is evaluated against analytical benchmarks, a standard finite difference scheme, and one public-domain computational package. Data sets reported from field tests are used for demonstrating the potential of the technique in simulating real situations.

Development of the Practical Method for Ion Influx, Efflux, and Net Flux Measurement in Plant Roots

Tracer experiments using radioisotope are powerful for the analysis of mineral uptake mechanisms in plant roots. In this study, we aimed to establish a quantitative method for measuring ion fluxes, i.e. net flux, influx, and efflux, which can be used to phenotyping of the mutants and natural variations. Consistency of obtained flux values for Mg2+ and Na+ was examined, and it was found that radioisotope absorption time of 20 s gave influx rate and an absorption time of more than 15 min gave net flux rate in rice roots. Furthermore, it was suggested that the longest possible radioisotope labeling time is necessary to increase the accuracy of the calculated efflux rate.