Effect of hypoxia induced by CoCl2 on VEGF expression in RPCs

AIM:To investigate the cobalt chloride(CoCl2)simulated hypoxic environment's effect on the gene expression and protein secretion of vascular endothelial growth factor(VEGF)of rats' retinal progenitor cells(RPCs). METHODS: RPCs were separated, cultured and identified by the use of neurospheres-adhesive culture. RT-PCR and ELISA were used to detect the change of RPCs VEGF's expression after 24-hour intervention of CoCl2 with different concentration(0, 50, 100, 150μmol/L and 200μmol/L), and detect the change of RPCs VEGF's expression in 150μmol/L CoCl2 for different period(0, 12, 24, 36, 48, 72 hours). RESULTS: The RPCs cultured by neurospheres-adhesive culture system could highly express the specificity of stem cells(Nestin), and express mature retinal neuron after natural differentiation. After culturing them in the hypoxic environment for the same period, the gene express of VEGF gradually increased and then decreased with the increasing concentration of CoCl2, and peaked(P≤0.05)when the concentration of CoCl2 was 150μmol/L. When the concentration of CoCl2 was 150μmol/L, the gene expression of VEGF also gradually increased and then decreased with the increasing hypoxia intervention period, and peaked(P≤0.05)when the hypoxia intervention period was 36 hours, the change of protein and gene expression were consistent. CONCLUSION: The RPCs cultured by neurospheres-adhesive culture system can better express the specificity of stem cells. Under CoCl2 simulated hypoxic environment, hypoxia strengthens RPCs VEGF's secretion and dependent on the time and dose

Characterization of removable elements with respect to having k disjoint bases in a matroid

AbstractThe well-known spanning tree packing theorem of Nash-Williams and Tutte characterizes graphs with k edge-disjoint spanning trees. Edmonds generalizes this theorem to matroids with k disjoint bases. For any graph G that may not have k-edge-disjoint spanning trees, the problem of determining what edges should be added to G so that the resulting graph has k edge-disjoint spanning trees has been studied by Haas (2002) [11] and Liu et al. (2009) [17], among others. This paper aims to determine, for a matroid M that has k disjoint bases, the set Ek(M) of elements in M such that for any e∈Ek(M), M−e also has k disjoint bases. Using the matroid strength defined by Catlin et al. (1992) [4], we present a characterization of Ek(M) in terms of the strength of M. Consequently, this yields a characterization of edge sets Ek(G) in a graph G with at least k edge-disjoint spanning trees such that ∀e∈Ek(G), G−e also has k edge-disjoint spanning trees. Polynomial algorithms are also discussed for identifying the set Ek(M) in a matroid M, or the edge subset Ek(G) for a connected graph G

Carbon dioxide dynamics from sediment, sediment-water interface and overlying water in the aquaculture shrimp ponds in subtropical estuaries, southeast China

Aquaculture ponds can emit a large amount carbon dioxide (CO2), with the consequence of exacerbating global climate change. Many studies about CO2 dynamics across the water-air interface, but CO2 in sediment and overlying water received relative less attention. In this study, CO2 concentration in sediment porewater, the diffusive CO2 fluxes across the sediment-water interface (SWI), and the CO2 production rates in the overlying water (CO2_WP) were determined in the shrimp ponds in the Min River Estuary (MRE) and Jiulong River Estuary (JRE), southeast China, to analyze the dynamics of CO2 among different growth stages of shrimps. Our results showed large variations in porewater CO2 concentrations, CO2 diffusive fluxes and CO2_WP rates among different growth stages, with markedly larger values in the middle stage of shrimp growth. The temporal variation of CO2 in both estuarine ponds followed closely the seasonal change of temperature. The internal CO2 production (CO2_IP) in these ponds was dominated by sediments. A significantly larger mean porewater CO2 concentrations, diffusive fluxes and production rate were observed in the MRE ponds than those in the JRE ponds, which could be attributed to the lower water salinity and a larger source of carbon substrates in the former estuary. Considering a total surface area of 6.63 × 103 km2 across the mariculture ponds in subtropical estuaries, it is estimated conservatively that approximately 100 Gigagram (Gg) of dissolved organic carbon and 190 Gg of dissolved inorganic carbon were transported annually from the mariculture ponds into China's coastal areas. Because of the substantial supply of dissolved carbon, the adjacent coastal waters receiving effluent discharge from the mariculture ponds could become “hotspots” of CO2 emissions. Our results highlight the role of aquaculture pond as a major CO2 source in China's coastal areas, and effective actions are needed to alleviate the greenhouse gas (GHG) emissions from these ponds

Production and uptake of dissolved carbon, nitrogen, and phosphorus in overlying water of aquaculture shrimp ponds in subtropical estuaries, China

Water quality deterioration can adversely affect the long-term sustainability of aquaculture industry. Understanding the processes of nutrient regeneration and uptake is important for improving water quality and the overall ecosystem health of aquaculture system. In spite of the importance of dissolved nutrients (DOC, DIC, N-NO , N-NH , and P-PO ) in governing water quality and ecosystem functioning, the spatiotemporal variations in the production and uptake of dissolved nutrients in aquaculture ponds is still poorly understood. In this study, the nutrient production and uptake rates in the overlying water were quantified among different shrimp growth stages in the aquaculture ponds in the Min River Estuary (MRE) and Jiulong River Estuary (JRE), southeast China. Significant differences in the nutrient production and uptake rates in the overlying water were observed among the three growth stages and two estuaries. The temporal variations of DOC and DIC production rates in both estuarine ponds closely followed the seasonal cycle of temperature, while the difference in DOC and DIC production rates between the two estuaries was likely caused by differences in water salinity. The changes in the production and uptake rates of dissolved inorganic nitrogen (N-NO and N-NH ) and P-PO in the water column over time were partly related to the interactions between thermal conditions and phytoplankton biomass (e.g., chlorophyll a concentrations) in the ponds. Our results demonstrate the complex dynamics and environmental risk of dissolved nutrients in subtropical shrimp ponds, and call for a more effective management of nutrient-laden wastewater in safeguarding the long-term sustainability of aquaculture production

Spontaneous Arrangement of Two-way Flow in Water Bridge

By revisiting the century-old problem of water bridge, we demonstrate that it is in fact dynamic and comprises of two coaxial currents that carry different charges and flow in opposite directions. Initially, the inner flow is facilitated by the cone jet that is powered by H+ and flows out of the anode beaker. The negative cone jet from cathode is established later and forced to take the outer route. This spontaneous arrangement of two-way flow is revealed by the use of chemical dyes, e.g., fluorescein and FeCl3, carbon powder, and the Particle Image Velocimetry. These two opposing flows are found to carry non-equal flux that results in a net transport of water to the cathode beaker. By combining the above information and taking into account the counter flow to equate the water level from the connecting pipe, we can estimate the cross section and flow speed of these co-axial flows as a function of time and applied voltage.Comment: 5 pages, 5 figure

Large fine‐scale spatiotemporal variations of CH4 diffusive fluxes from shrimp aquaculture ponds affected by organic matter supply and aeration in Southeast China

Mariculture shrimp ponds are important CH4 sources to the atmosphere. However, the spatiotemporal variations of CH4 concentration and flux at fine spatial scales in mariculture ponds are poorly known, particularly in China, worlds largest aquaculture producer. In this study, the plot‐scale spatiotemporal variations of water CH4 concentration and flux, both within and among ponds, were researched in shrimp ponds in Shanyutan wetland, Min River Estuary, Southeast China. The average water CH4 concentration and diffusion flux across the water‐air interface in the shrimp ponds over the shrimp aquaculture period varied from 2.29 ± 0.29 to 50.48 ± 20.91 μM and from 0.09 ± 0.01 to 2.32 ± 0.95 mmol·m−2·hr−1, respectively. The CH4 emissions from the estuarine ponds varied greatly between seasons, with peaks in August and September, which was similar to the trend of water temperature and dissolved oxygen concentrations. There was no remarkable difference in CH4 concentration and flux between shrimp ponds but significantly spatiotemporal differences in CH4 concentration and flux within the ponds. Significantly higher emissions occurred in the feeding zone, accounting for approximately 60% of total CH4 emission flux, while much lower CH4 emissions appeared in aeration zone, contributing 14% to total flux. This study suggests the importance of considering spatiotemporal variation in the whole‐pond estimates of CH4 concentration and flux. In light of such high spatial variation within ponds, improving aeration and feed utilization efficiency would help to mitigate CH4 emissions from mariculture ponds

Compositional and thermal characteristics of palm olein-based diacylglycerol in blends with palm super olein

Palm olein-based diacylglycerol (POL-DAG) was blended with palm super olein (POoo) in various concentrations (10–90%), with increments of 10% (wt/wt) POL-DAG. The physical and chemical characteristics, i.e., iodine value, acylglycerol content, fatty acid composition, melting and crystallization profiles and solid fat content, for POL-DAG, POoo and their binary blends were evaluated. The mid-infrared FTIR was used to determine the absorption bands of the different concentrations of the oil blends. Only slight differences of FAC and IV were observed. POL-DAG:POoo blends showed significant changes (p < 0.05) in DAG content and decreases in TAG content with increasing POL-DAG content. The DSC thermograms showed that the addition of different concentrations of POL-DAG changed the melting and crystallization behavior of the oil blends (POL-DAG:POoo). The crystallization onset point increased (p < 0.05) with an increasing POL-DAG concentration (10–90%). POL-DAG has the same absorption bands as POoo, with the exception of several minor peaks that appeared at (I) 2954 cm− 1, (II) 1267 cm− 1, (III) 1199 cm− 1, (IV) 1222 cm− 1 and (V) 966 cm− 1. This study will provide essential information for the palm oil industry to identify the most suitable POL-DAG blends with desirable physicochemical properties for food application purposes

Efficacy and safety of nanohybrids comprising silver nanoparticles and silicate clay for controlling Salmonella infection

Developing effective and safe drugs is imperative for replacing antibiotics and controlling multidrug-resistant microbes. Nanoscale silicate platelet (NSP) and its nanohybrid, silver nanoparticle/NSP (AgNP/NSP), have been developed, and the nanohybrids show a strong and general antibacterial activity in vitro. Here, their efficacy for protecting Salmonella-infected chicks from fatality and septicemia was evaluated. Both orally administrated NSP and AgNP/NSP, but not AgNPs alone, effectively reduced the systemic Salmonella infection and mortality. In addition, quantitative Ag analyses demonstrated that Ag deposition from AgNP/NSP in the intestines was less than that from conventional AgNPs, indicating that the presence of NSP for immobilizing AgNPs reduced Ag accumulation in tissue and improved the safety of AgNPs. These in vivo results illustrated that both NSP and AgNP/NSP nanohybrid represent potential agents for controlling enteric bacterial infections