The functional activity of donor kidneys is negatively regulated by microribonucleic acid-451 in different perfusion methods to inhibit adenosine triphosphate metabolism and the proliferation of HK2 cells.

This study explored the regulation of different perfusion methods on ischemia-reperfusion injury in donor kidneys. In this study, renal cortical/medullary tissue specimens were collected from porcine kidneys donors using different perfusion methods at various time points. Hematoxylin and eosin (H&E) staining was used to test the histological differences. Differentially expressed micro-ribonucleic acids (miRNAs) were identified by miRNA transcriptome sequencing. Reverse transcription-polymerase chain reaction (RT-PCR) tests were used to verify the changes in miRNAs in the kidney tissue taken from different perfusion groups. The related signaling pathways and the changes in the cell functions of different perfusion groups were analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) /Gene Ontology (GO) bioinformatics analyses. The effects of miRNA overexpression on the metabolism and proliferation of HK2 cells were detected by ATP kit and MTT assay. The H&E staining results showed that there were essentially no differences in the tissue samples among different perfusion groups at and before 12 h compared with a control group. The quantitative PCR results revealed that there was essentially no change in the expression of ssc-miR-451, ssc-miR-1285, and ssc-miR-486 in the cis infusion or joint infusion kidney groups, and their expression was significantly down-regulated over time in the trans-infusion kidney group. The bioinformatics analysis showed that the cellular component, molecular function, and biological processes of the kidney tissue, which had been perfused using three methods, had been consistently affected. The most significant changes after perfusion occurred in the intracellular metabolism signaling pathways. Furthermore, the energy metabolism and proliferation of the HK2 cells were significantly inhibited after the overexpression of miR-451. Specific miRNA markers, such as miR-451, may play a negative regulatory role in cell metabolism following the perfusion of kidney transplants using different methods.

Laparoscopic Orthotopic Kidney Transplantation in Swine: A Novel Vascular Prop Device for Venous Anastomoses.

Objective: To investigate the safety and efficacy of a vascular prop device for laparoscopic orthotopic kidney transplantation (LOKT) in swine. Material and Methods: Twenty swine were randomly divided into two groups. A vascular prop device was used in the observation (VP) group, and the vein beltization technique was used in the control (VB) group. The right kidney, as a donor graft, was laparoscopically transplanted to the location of the left kidney after a left nephrectomy. Data on the operative time, venous anastomotic time, vein stenosis, etc., and the survival of the swine in the two groups were recorded. Results: The mean transplant operative time, the mean cold ischemia time, and the venous anastomotic times in the VP group were significantly shorter than those in the VB group. Seven swine in the VP group and three swine in the VB group survived for 7 days. Autopsy results showed the occurrence of one artery stenosis and one vein stenosis in the VP group and one artery stenosis and five vein stenoses in the VB group. The median survival time was 6.25 days for the swine in the VP group and 4.40 days for those in the VB group. Conclusions: The vascular prop device is safe and feasible for LOKT in swine and may accelerate venous anastomosis and ensure the quality of venous anastomotic stoma.

A controllable double-cycle cryogenic device inducing hypothermia for laparoscopic orthotopic kidney transplantation in swine.

BACKGROUND: It is necessity to maintain donor kidneys at a low temperature for laparoscopic orthotopic kidney transplantation (LOKT). We recently designed a controllable double-cycle cryogenic device (DCD) with a safer and more effective cooling setting. This study aimed to evaluate the safety and efficacy of this device in a swine model. METHODS: A total of 20 pigs were procured for this study. We performed LOKT on 8 pigs using the controllable DCD for hypothermia, on another 8 pigs using the silicon tube cage (STC) for hypothermia, and on 4 pigs as the control group with no hypothermia measures (NH). The LOKTs were performed in autotransplantation mode in which the right kidney vein and artery were end-to-end anastomosed to the left kidney vein and artery in all three groups. The perioperative data, graft temperatures, and surgical complications were recorded, and histological examinations of kidney specimens were performed. RESULTS: The average surface temperature in the DCD group (5±3.5 °C) was significantly lower than that in the STC (10±5.5 °C) and NH (28±3.0 °C) groups. In the DCD and STC groups, the temperature between the cooling setting and the adjacent peritoneum was 30±3.0 and 12±5.0 °C, respectively. All pigs survived for 7 days in the DCD group. In the STC group, 2 pigs died from liver lesions and other causes. A single pig had diabetes insipidus. No pigs survived for 7 days in the NH group. The specimens from pigs immediately after revascularization and from the surviving pigs on day 7 following transplantation showed that the morphology of the glomerular and renal tubules was largely normal in the DCD and STC groups. However, in the NH group, there was minimal interstitial and tubular oedema, and endothelial cell swelling occurred in some specimens immediately after revascularization. Pathological examination of the harvested graft specimens showed severe acute tubular necrosis in the NH group. CONCLUSIONS: The newly designed controllable DCD can achieve the goal of cooling the kidney and warming the patient and may be a reliable, effective, inexpensive, and practical hypothermic maintenance system for LOKT in swine.

Effect of water flow on the release flux of dense non-aqueous phase liquids from the riverbed-take dichloromethane as an example.

This research is intended to study the effect of water flow on the release flux of DNAPLs, which have been deposited on the riverbed surface after sudden water pollution accidents. Those contaminants will slowly diffuse from the riverbed into the overlying water body through hydrodynamic action, causing ongoing and serious water pollution. By taking dichloromethane as a typical contaminant, the release form under different hydrodynamic conditions was observed through flume experiments, and the response relationship between the release flux and hydrodynamic factors was analyzed, with an emphasis on parameterizing the release rate. The results suggested that stronger water disturbance significantly enhanced the release of contaminants. And the relationship between the release flux and hydrodynamic factors generally followed an exponential distribution (R2 > 0.94). Besides, the mathematical relationships between the release flux and the average flow velocity, shear force and turbulent intensity were established as follows: F=183.63×e0.332u-, F=617.78×e22.292τ and F=119.03×e2.127TKE. Thus, this study has offered a solution to solve the source term quantification problem of the differential equation of convective diffusion, which can provide the basis for further developing the mathematical models of this kind of pollutants.

Applying steel slag leachate as a reagent substantially enhances pH reduction efficiency for humidification treatment.

A cost-effective, easy-to-implement, and sustainable approach is needed to mitigate the production of alkaline leachate from steel slags that are reused or disposed in the environment. To address this issue, a humidification treatment process, which is operated by wetting a stack of steel slag using aqueous reagents and letting atmospheric CO2 to be passively diffused into the slag pores to induce slag carbonation reaction, was previously developed. In this study, we demonstrate that the leachate of raw steel slag can be recycled and used as a humidification reagent to substantially enhance the treatment efficiency as well as to enable operating the process with neither synthetic chemical consumption nor wastewater discharge. In a 24-h study, a 0.61-unit reduction in slag pH is achieved using a raw slag leachate as a reagent, which is substantially greater than a 0.28-unit reduction using deionized water. The net amount of CaCO3 produced during an extended humidification duration of 4 weeks is increased by 2.7-fold when the leachate is used instead of deionized water. A series of systematically designed experiments demonstrates that the pH (11.0) and ionic strength (0.0048) are the two major characteristics of the raw slag leachate that contribute to the enhanced efficiency of humidification treatment. With further demonstration at larger scales in follow-up studies, the novel humidification process that utilizes the leachate generated on-site as a reagent is expected to be a feasible alternative for alkali waste treatment prior to its reuse or disposal.

Simulation for dynamic release of oil from oil-contaminated marine sediment.

Dynamic oil release from oil-contaminated sediment to seawater was investigated in kinetic and factor experiments. Oil-release kinetic was described using a two-compartment first-order equation with rapid- and slow-release steps. The rapid-desorption-fraction rate (kr) was not affected by the ratio of solid-liquid, but significantly affected by sediment pollution level and salinity. The slow-desorption-fraction rate constant (ks) was affected by sediment pollution level, the ratio of solid-liquid, and salinity. Desorption efficiencies were 1.09-4.04%, increasing as the sediment pollution level and salinity increased and the ratio of solid-liquid decreased. Oil desorption was critically affected by sediment suspension (or lack of). The desorption kinetics curves were unaffected with the shear force for unsuspended sediment, and the desorption efficiency and kr were increasing with the shear force for suspended sediment, and no significant correlations were found between ks and hydrodynamic conditions. The results provide a theoretical basis for evaluating ecological risks posed by oil in sediment.

Reduction of steel slag leachate pH via humidification using water and aqueous reagents.

A slag humidification process that aims to reduce the leachate pH of steel slag via carbonation was accomplished by simply wetting the slag and exposing it to the atmosphere for passive diffusion of atmospheric CO2. The optimization parameters of the process were studied. Results showed that by wetting the slag using various aqueous solutions (deionized water, NaCl solution and NaOH solution), such that its moisture content nearly reaches its water holding capacity, a significant reduction in leachate pH could be achieved. Pretreatment of the slag using 1 M NaOH and subsequent humidification using deionized water showed the best efficiency of 1.1 pH unit reduction among the tested conditions. Slag pretreatment could substantially enhance the carbonation degree on the slag surface, leading to conservation of the treatment effectiveness up to three times the leachate replenishment using deionized water. The benefit of the alkaline treatment to promote slag carbonation could also be achieved using a low to moderate (0.005-0.1 M) NaOH solutions for humidification without the pretreatment step. A 72.5% increase in the treatment efficiency could be achieved via a humidification treatment using 0.005 M NaOH solution compared to that using deionized water. This study shows the promise of humidification treatment as a low-cost, easily implemented, and environmentally friendly slag pH neutralization process that can be applied in the field for slag treatment prior to its use or disposal in the environment.

Water Environmental Capacity Calculated Based on Point and Non-Point Source Pollution Emission Intensity under Water Quality Assurance Rates in a Tidal River Network Area.

A mathematical model for simulating hydrodynamics and pollutants migration in a tidal river network was constructed, which takes the temporal and spatial distribution of rainfall runoff and non-point pollutants into consideration. Under the design hydrologic conditions of a typical hydrological year, the daily concentration change process for the control section is obtained. Aiming at the uncertainty of hydrology and water quality parameters such as flow direction, flow rate and concentration change in tidal river network area, a statistical analysis method is used to obtain the maximum allowable concentration of pollutants in the control section under the condition of the water quality standard assurance rate of. Then, a formula for calculating the pollutions emission intensity of point and non-point sources is derived. The method was applied to the pollution source control in a typical region like Taihu in China.

Simulated oil release from oil-contaminated marine sediment in the Bohai Sea, China.

There is a high degree of heavy oil partitioning into marine sediments when an oil spill occurs. Contaminated sediment, as an endogenous pollution source, can re-pollute overlying water slowly. In this study, a static oil release process and its effects in marine sediment was investigated through a series of experiments with reproductive heavy oil-contaminated marine sediment. The oil release process was accurately simulated with a Lagergren first-order equation and reached equilibration after 48h. The fitted curve for equilibrium concentration (C0) and first-order rate constant (k1) for sediment pollution levels exhibited a first-order log relationship. The instantaneous release rate (dCtdt) was also calculated. The C0 increased with increases in temperature and dissolved organic matter (DOM), and decreasing salinity. The k1 increased with temperature, but was not affected by DOM and salinity. These results can be used to better understand the fate of heavy oil in contaminated sediments of the Bohai Sea.

[Temporal and spatial distribution characteristics of nitrogen losses in hilly area of Taihu Lake].

Four typical land uses in hilly area of Taihu Lake were studied on temporal and spatial distribution characteristics of nitrogen losses in surface runoff under natural rainfall through experiment in situ. The medium value of event mean concentration (EMC) of ammonia nitrogen (NH4(+) -N) which dominated agricultural N in surface runoff accounted for 44.5% of total nitrogen (TN), while nitrite nitrogen (NO2(-) -N) accounted for 1.8%. Concentration of nitrogen in runoff had significantly seasonal variation which was related to meteorologic conditions such as rainfall, temperature, and agricultural activities. Temporal variabilities of site mean concentration (SMC) for TN, NH4(+) -N, NO3(-) -N and NO2(-) -N were decreased sequentially. The highest SMC value of TN, NH(+) -N and NO3(-) -N in upland runoff and N2(-) -N in bamboo grove were observed. The spatial distribution of nitrogen losses was determined by fertilizer application and vegetation coverage. Spatial variabilities for SMC of nitrogen were less than temporal variabilities. It was found that transportation fluxes of nitrogen in surface runoff from upland and vegetable plot were higher than that from chestnut orchard and bamboo forest which have significantly related to surface runoff volume.