Ammonia oxidizing archaea and bacteria respond to different manure application rates during organic vegetable cultivation in Northwest China.

Ammonia oxidization is a critical process in nitrogen cycling that involves ammonia oxidizing archaea (AOA) and bacteria (AOB). However, the effects of different manure amounts on ammonia-oxidizing microorganisms (AOMs) over the course of organic vegetables production remains unclear. We used the amoA gene to evaluated AOMs abundance and community structure in organic vegetable fields. Quantitative PCR revealed that AOB were more abundant than AOA. Among them, the amoA copy number of AOB treated with 900 kgN ha-1 was 21.3 times that of AOA. The potential nitrification rate was significantly correlated with AOB abundance (P < 0.0001) but not with AOA, suggesting that AOB might contribute more to nitrification than AOA. AOB sequences were classified into Nitrosomonas and Nitrosospira, and AOA into Nitrosopumilus and Nitrososphaera. Nitrosomonas and Nitrosopumilus were predominant in treatments that received manure nitrogen at ≥ 900 kg ha-1 (52.7-56.5%) and when manure was added (72.7-99.8%), respectively, whereas Nitrosospira and Nitrososphaera occupied more than a half percentage in those that received ≤ 600 kg ha-1 (58.4-84.9%) and no manure (59.6%). A similar manure rate resulted in more identical AOMs' community structures than greater difference manure rate. The bacterial amoA gene abundances and ratios of AOB and AOA showed significantly positive correlations with soil electrical conductivity, total carbon and nitrogen, nitrate, phosphorus, potassium, and organic carbon, indicating that these were potential key factors influencing AOMs. This study explored the AOMs' variation in organic vegetable fields in Northwest China and provided a theoretical basis and reference for the subsequent formulation of proper manure management.

Intra-Operative Neurophysiological Monitoring in Patients with Thoracic Spinal Stenosis: Its Feasibility and High-Risk Factors for New Neurological Deficit.

OBJECTIVE: Considering the high risk of postoperative neurological complications for patients with thoracic spinal stenosis (TSS), intra-operative neurophysiological monitoring (IONM) has been used for detecting possible iatrogenic injury timely. However, the IONM waveforms are often unreliable. This article is designed to determine the test performance of somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) during surgical thoracic decompression in patients with TSS, and to investigate the risk factors associated with deteriorated neurologic function at immediate postoperation. METHODS: Patients undergoing posterior spinal fusion from February 2009 to December 2020 were retrospectively reviewed. Patients were divided into the deteriorated neurologic function (DNF) group and the improved/intact neurological function (INF) group based on the postoperative neurological status. Demographic parameters such as gender, age, height, weight, etiology and IONM data were compared between groups. Demographics and IONM data between DNF and INF groups were compared by independent t or nonparametric tests. The incidence of abnormal SEP was analyzed by Chi-square test. RESULTS: A total of 108 patients (63 males, 45 females) with an average age of 53.5 ± 14.0 years were included. The SEP and MEP records were available in 94 and 98 patients, with the overall success rates being 87.0% and 90.7%, respectively. The sensibilities and specificities were 100% and 88.2% for SEP, 100% and 98.8% for MEP, respectively. There were 17 patients in DNF group and 91 patients in INF group. High weight (79.1 ± 14.6 vs 69.7 ± 15.7 kg, P = 0.024), high inter-side difference of MEP amplitude (899.1 ± 997.5 vs 492.3 ± 512.4 µV, P = 0.013) and high incidence of abnormal SEP (94.1% vs 64.8%, P = 0.024) were observed in the DNF group. Fourteen (82.4%) patients in the DNF group showed improvement in neurological status during follow-up. CONCLUSIONS: The overall success rates were 87.0% for SEP and 90.7% for MEP in patients with TSS.

Intra-operative Neurophysiological Monitoring in Patients Undergoing Posterior Spinal Correction Surgery with Pre-operative Neurological Deficit: Its Feasibility and High-risk Factors for Failed Monitoring.

OBJECTIVE: Considering spinal deformity patients with pre-operative neurological deficit were associated with more intra-operative iatrogenic neurological complications than those without, intra-operative neurophysiological monitoring (IONM) has been used for detecting possible iatrogenic injury timely. However, the IONM waveforms are often unreliable. To analyze the performance of intra-operative neurophysiological monitoring (IONM) including somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) in patients with pre-operative neurological deficit undergoing posterior spinal correction surgery, and to identify the high-risk factors for failed IONM. METHODS: Patients with pre-operative neurological deficit undergoing posterior spinal correction surgery between October 2017 and January 2022 were retrospectively reviewed. The presence or absence of SEP and MEP of target muscles were separately recorded. The P37/N50 latency and amplitude of SEP, and the MEP amplitude were measured. Any IONM alerts were also recorded. The IONM performance was compared among patients with different etiologies, levels responsible for neurological deficit, and strength of IONM-target muscles. Patients' demographics were analyzed using the descriptive statistics and were presented with mean ± standard deviation. Comparison analysis was performed using χ2 -test and statistically significant difference was defined as p < 0.05. RESULTS: A total of 270 patients (147 males, 123 females) with an average age of 48.4 ± 36.7 years were involved. The SEP records were available in 371 (68.7%) lower extremities while MEP records were available in 418 (77.4%). SEP alerts were reported in 31 lower extremities and MEP alerts in 22, and new neurological deficit at post-operation was observed in 11. The etiologies of neuromuscular and syndromic indicated relatively lower success rates of IONM, which were 44.1% and 40.5% for SEP, and 58.8% and 59.5% for MEP (p < 0.001). In addition, patients with pre-operative neurological deficit caused by cervical spine and muscle strength lower than grade 4 suffered from higher risk of failed IONM waveforms (p < 0.001). CONCLUSION: Patients with pre-operative neurological deficit suffered from a higher incidence of failed IONM results. The high-risk for failed IONM waveforms included the neuromuscular and syndromic etiologies, neurological deficit caused by cervical spine, muscle strength lower than grade 4 in patients with pre-operative neurological deficit undergoing posterior spinal correction surgery.

Performance analysis of two typical greenhouse lettuce production systems: commercial hydroponic production and traditional soil cultivation.

Introduction: Due to the shortage of land and water resource, optimization of systems for production in commercial greenhouses is essential for sustainable vegetable supply. The performance of lettuce productivity and the economic benefit in greenhouses using a soil-based system (SBS) and a hydroponic production system (HPS) were compared in this study. Methods: Experiments were conducted in two identical greenhouses over two growth cycles (G1 and G2). Three treatments of irrigation volumes (S1, S2, and S3) were evaluated for SBS while three treatments of nutrient solution concentration (H1, H2, and H3) were evaluated for HPS; the optimal levels from each system were then compared. Results and discussion: HPS was more sensitive to the effects of environmental temperature than SBS because of higher soil buffer capacity. Compared with SBS, higher yield (more than 134%) and higher water productivity (more than 50%) were observed in HPS. We detected significant increases in ascorbic acid by 28.31% and 16.67% and in soluble sugar by 57.84% and 32.23% during G1 and G2, respectively, compared with SBS. However, nitrate accumulated in HPS-grown lettuce. When the nutrient solution was replaced with fresh water 3 days before harvest, the excess nitrate content of harvested lettuce in HPS was removed. The initial investment and total operating cost in HPS were 21.76 times and 47.09% higher than those in SBS, respectively. Consideration of agronomic, quality, and economic indicators showed an overall optimal performance of the H2 treatment. These findings indicated that, in spite of its higher initial investment and requirement of advanced technology and management, HPS was more profitable than SBS for commercial lettuce production.

Soil moisture and nitrate-nitrogen dynamics and economic yield in the greenhouse cultivation of tomato and cucumber under negative pressure irrigation in the North China Plain.

A field experiment was carried out for two years to investigate the benefits of negative pressure water supply on surface soil water content, nitrate-nitrogen (NO3--N) distribution in the soil profile, economic yield and water and fertilizer use efficiency of tomato and cucumber under greenhouse cultivation in the North China Plain. The experiment included two irrigation treatments: drip irrigation with nutrient solution (DIN) and negative pressure irrigation with nutrient solution (NIN). The results showed that the NIN treatment had a relatively stable soil moisture (about 87% of field capacity), and the fluctuation of soil water content in the 0-20 cm soil layer was 20.6%-25.0% during the experiment period in 2014-2015, which was less than the range of 19.2%-28.1% in the DIN treatment. In both the DIN and NIN treatments, the NO3--N at the end of the four growing seasons was mainly distributed in the 0-40 cm soil layer and showed a gradually increasing trend as the number of cultivation years increased. Compared with the DIN treatment, the NO3--N content in the 0-60 cm layer of the NIN treatment was significantly decreased by 19.7%-28.0% after the fourth growing season. The NIN treatment produced the highest economic yield with lower water and nutrient input than the DIN treatment, however, no significant difference was observed in tomato and cucumber yield in the two years. Average irrigation water use efficiency (WUEi) and partial factor productivity of fertilizer (PFPf) over the study period were all significantly improved under the NIN treatment relative to the DIN treatment, with increases of 26.2% and 25.7% (P < 0.05), respectively. Negative pressure water supply not only maintained a high fruit yield, but significantly increased WUEi and PFPf, indicating a great advantage in water and fertilizer saving compared with drip irrigation.