Understory fuel loads and the impact factors of Quercus mongolica natural secondary forest in Hebei Pro-vince, China.

We investigated understory fuel loads of Quercus mongolica natural secondary forests in Hebei Province, China. We analyzed the effects of stand factors, topographic factors, and ground cover factors on the quantity and composition of fuel, established the dynamic models of understory fuel loads, and proposed management measures. The results showed that the understory total fuel load in Q. mongolica natural secondary forests was 11.68 t·hm-2, which exceeded the forest fire potential threshold (10 t·hm-2). The understory dead fuel load was mainly humus, and the understory living fuel load was mainly shrubs. The 1 h time-lag fuel load increased significantly with increasing canopy density, stand density, stand age, and litter thickness. The 10 h time-lag fuel load increased signi-ficantly with increasing stand density, average tree height, and litter thickness. Humus load decreased significantly with increasing altitude and increased significantly with increasing humus thickness. Herb load increased significantly with increasing sunny slope orientation and herbal coverage. Shrub load increased significantly with increasing slope degree, shrub coverage, and humus thickness. Understory total fuel load decreased significantly with increasing altitude, and increased significantly with increasing stand density, humus thickness, and litter thickness. The results of stepwise regression analysis indicated that stand density, humus thickness, and altitude could better predict the understory total fuel load (Radj2=0.775). Therefore, more attention should be paid on the control of stand density of Q. mongolica natural secondary forest in Hebei Province. Cleaning of litters and humus on the ground would help prevent forest fires scientifically and effectively.

Risk factors for acute kidney injury in patients with acute myocardial infarction.

BACKGROUND: Acute kidney injury (AKI) is a serious and fatal complication of acute myocardial infarction (AMI). It has high short- and long-term mortality rates and a poor prognosis but is potentially preventable. However, the current incidence, risk factors, and outcomes of AKI in the Chinese population are not well understood and would serve the first step to identify high-risk patients who could receive preventative care. METHODS: The medical data of 1124 hospitalized patients diagnosed with AMI from October 2013 to September 2015 were reviewed. AKI was defined according to the 2012 Kidney Disease Improving Global Outcomes criteria. All the patients were divided into either the AKI group or the non-AKI group. A univariate comparison analysis was performed to identify possible risk factors associated with AKI. A multiple logistic regression analysis was used to identify the independent risk factors for AKI in patients with AMI. RESULTS: Overall, the incidence of AKI was 26.0%. The mortality rate of the AKI group was 20.5%, and the mortality rate of the non-AKI group was 0.6% (P < 0.001). Logistic regression analysis showed that the independent risk factors for AKI in patients with AMI included: age (>60 years old) (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.05, P = 0.000), hypertension (OR 2.51, 95% CI 1.62-3.87, P = 0.000), chronic kidney disease (OR 3.52, 95% CI 2.01-6.16, P = 0.000), Killip class ≥3 (OR 5.22, 95% CI 3.07-8.87, P = 0.000), extensive anterior myocardial infarction (OR 3.02, 95% CI 1.85-4.93, P = 0.000), use of furosemide (OR 1.02, 95% CI 1.02-1.03, P = 0.000), non-use of angiotensin-converting enzyme inhibitors/angiotensin receptor blocker (OR 1.58, 95% CI 1.04-2.40, P = 0.032). These factors provided an accurate tool to identify patients at high risk of developing AKI. CONCLUSIONS: Approximately 26.0% of patients undergoing AMI developed AKI, and the development of AKI was strongly correlated with in-hospital mortality. The risk factors for AKI in patients with AMI were determined to help identify high-risk patients and make appropriate clinical decisions.

The effects of different levels of superoxide dismutase in Modena on boar semen quality during liquid preservation at 17°C.

This study was conducted to investigate the influence of superoxide dismutase (SOD) on the quality of boar semen during liquid preservation at 17°C. Semen samples from 10 Duroc boars were collected and pooled, divided into five equal parts and diluted with Modena containing different concentrations (0, 100, 200, 300 and 400 U/mL) of SOD. During the process of liquid preservation at 17°C, sperm motility, acrosome integrity, membrane integrity, total antioxidant capacity (T-AOC) activity, malondialdehyde (MDA) content and hydrogen peroxide (H2 O2 ) content were measured and analyzed every 24 h. Meanwhile, effective survival time of boar semen during preservation was evaluated and analyzed. The results indicated that different concentrations of SOD in Modena showed different protective effects on boar sperm quality. Modena supplemented with SOD decreased the effects on reactive oxygen species on boar sperm quality during liquid preservation compared with that of the control group. The added 200 U/mL SOD group showed higher sperm motility, membrane integrity, acrosome integrity, effective survival time and T-AOC activity. Meanwhile, the added 200 U/mL SOD group showed lower MDA content and H2 O2 content. In conclusion, addition of SOD to Modena improved the boar sperm quality by reducing oxidative stress during liquid preservation at 17°C and the optimum concentration was 200 U/mL.