[Response of Soil Enzyme Activity and Chemical Properties to Nitrogen Addition in a Korean Pine Plantation].

Soil enzymes participate in numerous complex biochemical processes that take place in the soil and play an important role in the material circulation of terrestrial ecosystems. To explore the response of soil enzyme activities and chemical properties to nitrogen deposition in temperate forests, this study analyzed four soil enzyme activities based on the nitrogen addition experiment plot of Korean pine (Pinus koraiensis) plantation, which was located in the Liangshui National Natural Reserve, Heilongjiang Province. The results showed that the activities of N-acetyl-glucosidase (NAG) and alkaline phosphatase (AKP) increased significantly with increasing nitrogen application concentration. The activity of beta-glucosidase (BG) and acid phosphatase (ACP) was not significantly different among different nitrogen application treatments. The contents of total carbon, total nitrogen, total phosphorus, and available nitrogen and four enzyme activity in the upper soil (0-10 cm) under the same nitrogen application level were significantly higher than those in the lower soil (10-20 cm), but the pH values were not significantly different. Total carbon has an extremely significant positive correlation with NAG, BG, AKP, and ACP. Total nitrogen has an obvious or extremely significant positive correlation with BG, NAG, and AKP as well as ACP. The available nitrogen has an obvious and highly significant positive correlation with NAG and AKP. The total phosphorus has an obvious and extremely significant positive correlation with ACP and AKP, respectively. The nitrogen application level and the soil layer had different effects on soil enzyme activity and soil chemical properties. Long-term large input of nitrogen can directly or indirectly change soil chemical properties and affect soil enzyme activity.

Are Routine Postoperative Laboratory Tests Really Necessary After Lumbar Spinal Surgery?

BACKGROUND: For patients undergoing lumbar spinal surgery, many surgeons routinely perform laboratory tests within 3 days after surgery. However, few studies have reported the necessity for routine laboratory tests for patients with uncomplicated cases within 3 days after surgery. METHODS: We performed a retrospective study of patients with lumbar degenerative disease who had undergone lumbar spinal surgery from May 2014 to May 2017. The perioperative patient information was recorded. The abnormal postoperative laboratory tests were recorded. Finally, the incidence and risk factors for patients requiring postoperative clinical treatment were analyzed. RESULTS: A total of 1915 patients were included in the present study. Postoperative laboratory tests had been ordered for 870 patients (45.43%). Of these patients, only a small proportion had required postoperative clinical intervention to treat abnormal serum hemoglobin (2.53%), albumin (1.95%), serum potassium (0.92%), or serum calcium (6.55%) levels. Multivariate logistic regression analysis showed that female gender and operative time were risk factors for the need for blood transfusion after lumbar spinal surgery. Age and operative time were risk factors for patients requiring albumin supplementation after lumbar spinal surgery. Finally, intraoperative blood loss and operative time were independent risk factors for patients requiring calcium supplementation after surgery. CONCLUSIONS: Owing to the small number of postoperative clinical interventions for abnormal laboratory test results, we believe that the use of routine laboratory tests within 3 days after lumbar spinal surgery for patients with uncomplicated cases are unnecessary. Our results showed that operative time is a potential risk factor for the necessity for clinical treatment after lumbar spinal surgery.

[Effects of gamma linolenic acid on atherosclerosis induced by cholesterol-rich diet in rats].

OBJECTIVE: To study the effect of gamma linolenic acid (GLA) on atherogenesis in rats. METHOD: Sixty healthy male rats were randomly divided into 6 groups: normal contro 1, fed by normal feed; atherogenesis mode 1, fed by high lipid diet; positive control group 0.9 mg x kg(-1) x d(-1) of lovastatin and group IV 250 mg x kg(-1) x d(-1) duoxikang; high dose of 375 mg x kg(-1) x d(-1) GLA; low dose of 187.5 mg x kg(-1) x d(-1) GLA. After the model group received atherogenic diet for six weeks, serum triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were detected by enzyme method to confirm the formation of atherogenic. After fed for another five weeks, morphologic atherosclerosis of aorta in rats was observed by HE staining methods. The blood samples were collected and serum TC, TG, HDL-C, LDL-C, T-AOC, HL, LPL, NO, NOS, MDA and GSH were determined. RESULT: GLA attenuated the formation of atherosclerotic plaques, inhibited the level of serum TC, TG, MDA, OX-LDL, NO, NOS, HL, LPL and LDL-C and increased the level of T-AOC. CONCLUSION: GLA might significantly attenuate the development of atherosclerosis in rats fed with high lipid diet through improving the antioxidation capacity of the body.

Biosorption of uranium by lake-harvested biomass from a cyanobacterium bloom.

The aim of this work was to study some basic aspects of uranium biosorption by powdered biomass of lake-harvested cyanobacterium water-bloom, which consisted predominantly of Microcystis aeruginosa. The optimum pH for uranium biosorption was between 4.0 and 8.0. The batch sorption reached the equilibrium within 1 h. The isotherm fitted the Freundlich model well. Although the Langmuir model fitted the experiment data well at pH 3.0, 5.0 and 7.0, it did not fit at pH 9.0 and 11.0 at all. This implies that different biosorption mechanisms may be involved at different pH values. 0.1 N HCl was effective in uranium desorption. The results indicated that the naturally abundant biomass of otherwise nuisance cyanobacterium bloom exhibited good potential for application in removal of uranium from aqueous solution.