Dissecting basilar artery aneurysm manifesting as sudden sensorineural hearing loss: a case report and literature review.

Highlights • Dissecting basilar artery aneurysm (DBAA) is relatively rare. • We report the first case of a DBAA manifesting as sudden sensorineural hearing loss. • This case report adds to the symptom spectrum of DBAA.

Effects of combined application of nitrogen fertilizer and biochar on the nitrification and ammonia oxidizers in an intensive vegetable soil.

Soil amended with single biochar or nitrogen (N) fertilizer has frequently been reported to alter soil nitrification process due to its impact on soil properties. However, little is known about the dynamic response of nitrification and ammonia-oxidizers to the combined application of biochar and N fertilizer in intensive vegetable soil. In this study, an incubation experiment was designed to evaluate the effects of biochar and N fertilizer application on soil nitrification, abundance and community shifts of ammonia-oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in Hangzhou greenhouse vegetable soil. Results showed that single application of biochar had no significant effect on soil net nitrification rates and ammonia-oxidizers. Conversely, the application of only N fertilizer and N fertilizer + biochar significantly increased net nitrification rate and the abundance of AOB rather than AOA, and only AOB abundance was significantly correlated with soil net nitrification rate. Moreover, the combined application of N fertilizer and biochar had greater effect on AOB communities than that of the only N fertilizers, and the relative abundance of 156 bp T-RF (Nitrosospira cluster 3c) decreased but 60 bp T-RF (Nitrosospira cluster 3a and cluster 0) increased to become a single predominant group. Phylogenetic analysis indicated that all the AOB sequences were grouped into Nitrosospira cluster, and most of AOA sequences were clustered within group 1.1b. We concluded that soil nitrification was stimulated by the combined application of N fertilizer and biochar via enhancing the abundance and shifting the community composition of AOB rather than AOA in intensive vegetable soil.

Short-term alteration of nitrogen supply prior to harvest affects quality in hydroponic-cultivated spinach (Spinacia oleracea).

BACKGROUND: Quality-associated problems, such as excessive in planta accumulation of oxalate, often arise in soillessly cultivated spinach (Spinacia oleracea). Maintaining a higher level of ammonium (NH4⁺) compared to nitrate (NO3⁻) during the growth period can effectively decrease the oxalate content in hydroponically cultivated vegetables. However, long-term exposure to high concentrations of NH4⁺ induces toxicity in plants, and thus decreases the biomass production. Short-term application of NH4⁺ before harvesting in soilless cultivation may provide an alternative strategy to decrease oxalate accumulation in spinach, and minimise the yield reduction caused by NH4⁺ toxicity. RESULT: The plants were pre-cultured in 8 mmol L⁻¹ NO3⁻ nutrient solution. Next, 6 days before harvest, the plants were transferred to a nutrient solution containing 4 mmol L⁻¹ NO3⁻ and 4 mmol L⁻¹ NH4⁺. This new mix clearly reduced oxalate accumulation, increased levels of several antioxidant compounds, and enhanced antioxidant capacity in the edible parts of spinach plants, but it did not affect biomass production. However, when the 8 mmol L⁻¹ NO3⁻ was shifted to either nitrogen-free, 4 mmol L⁻¹ NH4⁺ or 8 mmol L⁻¹ NH4⁺ treatments, although some of the quality indexes were improved, yields were significantly reduced. CONCLUSIONS: Short-term alteration of nitrogen supply prior to harvest significantly affects quality and biomass of spinach plants, and we strongly recommend to simultaneously use NO3⁻ and NH4⁺ in hydroponic cultivation, which improves vegetable quality without decreasing biomass production.