[Characteristics of Modified Biochars and Their Immobilization Effect on Cu and Cd in Polluted Farmland Soil Around Smelter]

Heavy metals in farmland soil are one of the most hazardous pollutants in the environment, owing to their universality and irreversibility. Modified biochar has been widely used in the adsorption and immobilization of heavy metals in soil, and its applicability is mainly determined by the types of heavy metals, pollution levels, and soil environmental conditions. Soil pollution is gradually becoming more complex and diversified, and heavy metal pollutants mostly occur in the form of compound pollution. However, most studies have focused on single heavy metal pollutant or the addition of heavy metal to soil. This study used rice straw as a raw material to prepare biochar, and modified it with K₃PO₄, KMnO₄, and NaOH. The physicochemical and structural characteristics of the modified biochars were detected using a BET accelerated surface area and porosimetry system, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and the biochars were then analyzed for the availability and forms of Cd and Cu in soils contaminated with heavy metals in the mining area. The results showed that the surface roughness of the modified biochar increased to different degrees with increases in specific surface area and pore volume, with the NaOH modified biochar showing the most significant increases from 4.96 m²·g^-1 to 60.79 m²·g^-1, and from 0.02 cm³·g^-1 to 0.12 cm³·g^-1, respectively. The pore diameter changed in the opposite direction. The absorption peaks of the functional groups of the modified biochar were all changed, with K₃PO₄ modified biochar exhibiting the greatest degree of change. The addition of biochar significantly improved the soil pH value (P<0.05), and the pH value of the soil treated with K₃PO₄ modified biochar exhibited the largest increase. With an application of 20.5% K₃PO₄ modified biochar, the availability of Cu and Cd in the soil was significantly reduced, by 75.44% and 67.70%, respectively. The immobilization efficiency of Cu was much higher than that of Cd. The best immobilization efficiency of Cu and Cd in soil was achieved with K₃PO₄ modified biochar. With an addition of 2% K₃PO₄ modified biochar, the immobilization efficiency of Cu and Cd was 61.06% and 4.12%, respectively. In summary, K₃PO₄ modified biochar had a better immobilization effect on both Cu and Cd in compound contaminated soil.

Comparison of clinical outcomes of open, laparoscopic and single port appendicectomies

INTRODUCTION

Appendicectomy is the most common surgical procedure performed in general surgery. This study aimed to compare the outcomes of open appendicectomy (OA), laparoscopic appendicectomy (LA) and single port laparoscopic appendicectomy (SPLA).

METHODS

Fifty consecutive patients with suspected acute appendicitis were studied (OA: n=20, LA: n=20, SPLA: n=10). Clinical outcomes were compared between the three groups in terms of operative time, blood loss, postoperative complications, length of hospital stay and cost.

RESULTS

Patient demographics were similar among groups (p>0.05). SPLA was characterised by longer operative time (88.1 minutes vs 35.6 minutes in OA and 33.4 minutes in LA) and higher costs (12.84 thousand Chinese yuan [RMB] vs 8.41 thousand RMB in LA and 4.99 thousand RMB in OA). OA was characterised by more blood loss (9.8ml vs 7.5ml in SPLA and 6.8ml in LA), longer hospital stay (7.5 days vs 3.5 days in LA and 3.4 days in SPLA) and lower costs. The total number of complications was higher for OA (n=2) than for LA and SPLA (n=0) although this was not statistically significant.

CONCLUSIONS

Where feasible, LA should be undertaken as the initial treatment of choice for most cases of suspected appendicitis.

An electrogenic chloride pump in a zoological membrane

Two widely documented mechanisms of chloride transport across animal plasma membranes are anion-coupled antiport and sodium-coupled symport. No direct genetic evidence has yet been provided for primary active chloride transport despite numerous reports of cellular CI(-)-stimulated ATPases coexisting, in the same tissue, with uphill chloride transport that could not be accounted for by the two common chloride transport processes. CI(-)-stimulated ATPases are a common property of practically all animal cells, with the major location being of mitochondrial origin. It also appears that the plasma membranes of animal cells are sites of CI(-)-stimulated ATPase activity. Recent studies of CI(-)-stimulated ATPase activity and chloride transport in the same membrane system, including liposomes, suggest a mediation by the ATPase in net movement of chloride up its electrochemical gradient across animal plasma membranes. Further studies, especially from a molecular biological perspective, are required to confirm a direct transport role to plasma membrane-localized Cl(-)-stimulated ATPases.