[Effects of Dissolved Oxygen on Nutrient Removal Performance and Microbial Community in Low Carbon/Nitrogen Municipal Wastewater Treatment Process].

To explore the effects of dissolved oxygen (DO) on the treatment of low carbon/nitrogen municipal wastewater, this study examined the characteristics of the microbial community in a low carbon source environment. The treatment process was conducted with the aeration area having DO concentrations of 2-3, 1-2, and lower than 1 mg·L-1. The results demonstrated that reduced DO concentration in the aeration area increased the efficiency of the nitrogen removal process by 20.23% and 80.54%, for external and internal carbon sources, respectively. Similarly, the efficiency of internal carbon source utilization in the phosphorus removal process increased by 13.89%, thus enhancing the nutrient removal efficiency of the low carbon/nitrogen wastewater treatment system. High-throughput sequencing and RDA analysis showed that reduced oxygen concentration motivated an adjustment in microbial community structure, causing functional microorganisms (i.e., Dechloromonas) to become dominant. In addition, the upregulation of genes associated with energy production and conversion, signal transduction, substrate transport, and metabolism provided favourable nutritional conditions for the proliferation of functional microorganisms in low carbon source conditions. This study provides a theoretical basis for improving the growth of microorganisms involved in the nutrient removal process when treating low carbon/nitrogen municipal wastewater.

Open total dislocation of ankle joint without fractures: A case report.

RATIONALE: Open total dislocation of ankle joint is rare and often caused by high-energy injury. The present study describes a patient with open total lateral dislocation of ankle joint without fractures and obtained a satisfactory clinical result following early debridement and irrigation, one-stage repairment of ligaments, and plaster external fixation. PATIENT CONCERNS: The patient, a 45-year-old male, complained of right foot pain with bleeding and limited motion. Physical examination showed a 15-cm open wound at the medial ankle region, with soft tissues impaired and ankle bones exposed. The 3 dimensional reconstruction computed tomography (CT) examination showed an open total dislocation of ankle joint without concomitant fractures. DIAGNOSES: open total lateral dislocation of ankle joint without fractures. INTERVENTIONS: Early modern wound care including thorough debridement and irrigation on the wound was performed to remove contaminated soft tissues. Subsequently, the dislocated ankle joint was reduced by hand and the medial and lateral collateral ligaments were repaired using wire anchors. OUTCOMES: The medial wound healed at 2 weeks after surgery, and several common complications such as infection and skin necrosis did not occur. The last follow-up showed a good range of metatarsal flexion and extension of the injured foot, and obvious signs of traumatic arthritis were not observed. According to Kaikkonen ankle function score, the patient was assessed with 90 points. LESSONS: For open total dislocation of ankle joint, early treatment should focus on debridement and irrigation, reduction and fixation of the dislocated ankle, protection of the weak soft tissues, and stable external fixation to promote wound healing and reduce the incidence of related complications.

[Effects of Aeration Strategy on Denitrifying Performance of Activated Sludge Processes in Treating Low-Carbon-Source Municipal Wastewater].

In this study, the effects of aeration strategy on nitrogen removal performance of activated sludge processes in treating low-carbon-source municipal wastewater were investigated. Two aeration strategies (continuous aeration (CA) and intermittent aeration (IA)) were evaluated, and the long-term performance of activated sludge processes employing these strategies in treating wastewater with C/N=3 were analyzed. The results demonstrated that the total nitrogen removal efficiency in CA was 17.92% higher than that in the IA process. Meanwhile, the carbon source utilized in nitrogen removal in CA was 44.29% higher compared with the IA process. Furthermore, the results of 16S rRNA sequencing showed that relative abundances of denitrifying bacteria in CA and IA were 5.86% and 2.06%, respectively, suggesting that the CA process has better denitrification ability when treating low-carbon-source wastewater. In addition, 16S rRNA sequencing gene prediction was utilized to analyze the in-depth mechanisms. The results demonstrated that genes involved in membrane transport, carbohydrate metabolism, and cell composition were more highly expressed in CA. The enhancement of metabolic activity under continuous aeration strengthened microbial carbon source utilization. Therefore, the activated sludge process under continuous aeration was more efficient in treating low-carbon-source municipal wastewater. This study provides ideas for low-carbon-source municipal wastewater treatment.

Comparison of two methods of locating proximal femoral nail anti-rotation in the treatment of femoral intertrochanteric fractures.

BACKGROUND: To compare the efficacy of three-point locating versus routine locating techniques for implanting helical blades for proximal femoral nail anti-rotation-II in the treatment of trochanteric fractures. METHODS: From January 2010 to June 2013, 90 patients with intertrochanteric fractures were surgically treated, including 48 males and 42 females with an average age of 70.5 ± 7.2 years. According to the AO classification, there were 45 cases of A2.1, 35 cases of A2.2, and 10 cases of A2.3. Based on locating techniques, the 90 patients were divided into two groups: the three-point group and the routine group, with 45 patients in each group. All operations were performed by the same group of surgeons using proximal femoral nail anti-rotation (PFNA); the helical blade was inserted into the femoral neck with the three-point locating technique or by the usual method according to treatment group. Several figures including total operation time, elapsed time for implanting the helical blade, intraoperative blood loss, X-ray exposure time, and tip-apex distance (TAD) were measured and compared. RESULTS: The three-point group was significantly superior as compared to the routine group in terms of total operation time [(59.34 ± 9.42) min vs (67.61 ± 12.63) min, P < 0.01], elapsed time for implanting the helical blade [(4.58 ± 1.25) min vs (7.82 ± 2.19) min, P < 0.01], intraoperative blood loss [(92.78 ± 34.09) ml vs (154.01 ± 39.10) ml, P < 0.01], X-ray exposure time [(8.84 ± 1.45) vs (14.62 ± 2.91), P < 0.01], and tip-apex distance [(16.78 ± 1.55) mm vs (21.91 ± 3.01) mm, P < 0.01]. Among the 90 patients, 80 were followed up for an average time of 12 months (10-15 months), including 42 patients who were part of three-point group and 38 patients who were part of the routine group. No spiral blade cut was found on the femoral head in any patient in the three-point group, whereas it occurred in 2 patients in the routine group 1 month after surgery. However, there was no significant difference in the Harris score between the two groups 6 months after the operation. CONCLUSION: The three-point locating method is faster and more accurate than the routine locating method.