Nutrient removal through pyrrhotite autotrophic denitrification: Implications for eutrophication control.

This study investigated nutrient removal kinetics and main influencing factors of natural pyrrhotite autotrophic denitrification (PAD), and nutrient removal performance and the microbial community in the PAD biofilter (PADB). Results demonstrated that both NO3- and PO43- in wastewater were nearly completely removed, and biological N removal and chemical P removal took place simultaneously in the PAD process. NO3- removal kinetics of the PAD can be described with half-order kinetics. The PAD was effective across a wide temperature range of 11-34 °C, initial NO3--N range of 13-52 mg·L-1 and PO43--P below 60 mg·L-1. Both NO3- and PO43- decreased gradually with wastewater flowing along the PADB. The PADB operation results show that at 12 h HRT, when the PADB treated wastewater containing 30.95 ±â€¯0.97 mg·L-1 of NO3- and 3.02 ±â€¯0.10 mg·L-1 of PO43--P, the effluent contained 1.15 ±â€¯2.08 and 0.09 ±â€¯0.11 mg·L-1 of NO3--N and PO43--P on average, respectively. In the PADB the dominant bacteria were Thiobacillus and Sulfurimonas, which used pyrrhotite as the electron donor to reduce NO3-. The relative abundance of Thiobacillus at the bottom of the PADB increased from 0.81% to 58.65% and that of Sulfurimonas decreased from 97.22% to 12.30%, with exposure to pyrrhotite. From the bottom to the top of the PADB, the relative abundance of Thiobacillus increased from 58.65% to 86.23% and Sulfurimonas decreased from 12.30% to 0.52%. Technologies based on the PAD are promising ways to control eutrophication.

Natural pyrite to enhance simultaneous long-term nitrogen and phosphorus removal in constructed wetland: Three years of pilot study.

The searches for suitable substrates with high capacity for phosphorus (P) removal and promoting denitrification for enhancing nitrogen (N) removal have been a key work in constructed wetlands (CWs) research in the past several decades. But few substrates enhancing simultaneous long-term N and P removal in CWs have been found before. In this study, two subsurface flow pilot-scale wetlands using natural pyrite and limestone as substrates were constructed. After 3 year of operation, we found that pyrite had no negative effects on growth of reeds, removals of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N), but enhanced long-term total nitrogen (TN) and total phosphorus (TP) removals in constructed wetland. In the three years, the average TP and TN removals of pyrite constructed wetland (PCW) were 87.7 ± 14.2% with 0.25 ± 0.20 mg/L of average effluent TP and 69.4 ± 21.4% with 4.0 ± 3.2 mg/L of average effluent TN, respectively. The main P form in the PCW was (Fe + Al)-bound P. The mechanisms of the PCW with enhanced simultaneous long-term N and P removals were anaerobic and aerobic oxidations of pyrite. The main bacteria were Anaeromyxobacter (4.9%), Ramlibacter (4.8%), Defluviicoccus (4.2%), Azoarcus (3.7%), Geobacter (3.4%), and they were highly related to anaerobic and aerobic oxidation of pyrite in the PCW.

MicroRNA-221 promotes cell proliferation, migration, and differentiation by regulation of ZFPM2 in osteoblasts.

Bone fracture is a common medical condition, which may occur due to traumatic injury or disease-related conditions. Evidence suggests that microRNAs (miRNAs) can regulate osteoblast differentiation and function. In this study, we explored the effects and mechanism of miR-221 on the growth and migration of osteoblasts using MC3T3-E1 cells. The expression levels of miR-221 in the different groups were measured by qRT-PCR. Then, miR-221 mimic and inhibitor were transfected into MC3T3-E1 cells, and cell viability and migration were measured using the CCK-8 assay and the Transwell migration assay. Additionally, the expression levels of differentiation-related factors (Runx2 and Ocn) and ZFPM2 were measured by qRT-PCR. Western blot was used to measure the expression of cell cycle-related proteins, epithelial-mesenchymal transition (EMT)-related proteins, ZFPM2, and Wnt/Notch, and Smad signaling pathway proteins. miR-221 was significantly up-regulated in the patients with lumbar compression fracture (LCM) and trochanteric fracture (TF). miR-221 promoted ALP, Runx2, and OPN expressions in MC3T3-E1 cells. miR-221 overexpression significantly increased cell proliferation, migration, differentiation, and matrix mineralization, whereas suppression of miR-221 reversed these effects. Additionally, the results displayed that ZFPM2 was a direct target gene of miR-221, and overexpression of ZFPM2 reversed the promoting effects of miR-221 overexpression on osteoblasts. Mechanistic study revealed that overexpression of miR-221 inactivated the Wnt/Notch and Smad signaling pathways by regulating ZFPM2 expression. We drew the conclusions that miR-221 overexpression promoted osteoblast proliferation, migration, and differentiation by regulation of ZFPM2 expression and deactivating the Wnt/Notch and Smad signaling pathways.

MicroRNA-221 promotes cell proliferation, migration, and differentiation by regulation of ZFPM2 in osteoblasts

Bone fracture is a common medical condition, which may occur due to traumatic injury or disease-related conditions. Evidence suggests that microRNAs (miRNAs) can regulate osteoblast differentiation and function. In this study, we explored the effects and mechanism of miR-221 on the growth and migration of osteoblasts using MC3T3-E1 cells. The expression levels of miR-221 in the different groups were measured by qRT-PCR. Then, miR-221 mimic and inhibitor were transfected into MC3T3-E1 cells, and cell viability and migration were measured using the CCK-8 assay and the Transwell migration assay. Additionally, the expression levels of differentiation-related factors (Runx2 and Ocn) and ZFPM2 were measured by qRT-PCR. Western blot was used to measure the expression of cell cycle-related proteins, epithelial-mesenchymal transition (EMT)-related proteins, ZFPM2, and Wnt/Notch, and Smad signaling pathway proteins. miR-221 was significantly up-regulated in the patients with lumbar compression fracture (LCM) and trochanteric fracture (TF). miR-221 promoted ALP, Runx2, and OPN expressions in MC3T3-E1 cells. miR-221 overexpression significantly increased cell proliferation, migration, differentiation, and matrix mineralization, whereas suppression of miR-221 reversed these effects. Additionally, the results displayed that ZFPM2 was a direct target gene of miR-221, and overexpression of ZFPM2 reversed the promoting effects of miR-221 overexpression on osteoblasts. Mechanistic study revealed that overexpression of miR-221 inactivated the Wnt/Notch and Smad signaling pathways by regulating ZFPM2 expression. We drew the conclusions that miR-221 overexpression promoted osteoblast proliferation, migration, and differentiation by regulation of ZFPM2 expression and deactivating the Wnt/Notch and Smad signaling pathways.

[Clinical study thoracolumbar Chance fractures: a report of 21 cases].

OBJECTIVE: To discuss the mechanism, clinical characteristics, diagnosis and treatment of thoracolumbar Chance fractures. METHODS: Among all the 21 patients, 13 patients were male and 8 patients were female, ranging in age from 23 to 57 years, with an average of 32 years. The injury was at the level of T11 in 3 patients, at the level of T12 in 9 patients, at the level of L1 in 8 patients and at the level of L2 in 1 patient. According to Denis classification, 10 patients were type A, 2 type B, 5 type C, and 4 type D. All the patients were treated with pedicle screw internal fixation and posterior lateral fusion at the level of injury. RESULTS: Twenty-one patients had been followed up for an average of 18 months (13 to 28 months). According to ASIA neurologic grading system, 4 cases in grade C or D recovered to grade E postoperatively and one case in grade B was not improved. Postoperative X-ray showed good reduction and fixation in all cases and no looseness or breakage in the fixation system. The results of postoperative back pain and function assessment were mostly satisfactory. CONCLUSION: Thoracolumbar Chance fractures are due to flexion-distraction injuries and regarded as unstable, which are uncommon and usually not present with a neurologic deficit. Reduction and stabilization with posterior pedicle screw internal fixation is suggested in patients with thoracolumbar Chance fractures.

Elastic modulus of viral nanotubes.

We report an experimental and theoretical study of the radial elasticity of tobacco mosaic virus (TMV) nanotubes. An atomic force microscope tip is used to apply small radial indentations to deform TMV nanotubes. The initial elastic response of TMV nanotubes can be described by finite-element analysis in 5nm indentation depths and Hertz theory in 1.5nm indentation depths. The derived radial Young's modulus of TMV nanotubes is 0.92+/-0.15GPa from finite-element analysis and 1.0+/-0.2GPa from the Hertz model, which are comparable with the reported axial Young's modulus of 1.1GPa [Falvo, Biophys. J. 72, 1396 (1997)].

[Internal fixation for pelvic posterior ring lesions].

OBJECTIVE: To explore the choice for the internal fixation in treatment of pelvic posterior lesions. METHODS: From May 2000 to June 2005, the treatment was given to 40 patients (28 males, 12 females, aged 21-58 years) with pelvic posterior ring fracture and dislocation. Of the patients, 23 had a traffic accident, 11 had a crush injury and 6 had a fall. As for the state of an injury to the pelvic posterior ring, 22 patients had dislocation of the sacroiliac joint, 12 had a sacrum fracture dislocation, and 6 had an ala iliac fracture and dislocation of the sacroiliac joint. According to the Denis (1988) classification, fracture of the (sacral region I was found in 6 cases, fracture of the sacral) region II in 3 cases, and fracture of the sacral region III in 3 cases. As for the complication of the pelvic front ring fracture: separation of the symphysis pubis was found in 14 cases, fracture of the superior ramus and inferior ramus of the pubis on one side in 10 cases. The two-side superior ramus of public and inferior ramus of pubis in 8 cases, homopleural acetabular fracture on one side in 4 cases, acetabular fracture on one side and contralateral superior ramus and inferior ramus fracture of the pubis in 3 cases, and acetabular fracture on the opposite side in 1 case. As for the operation, 28 patients underwent the still-plate internal fixation of the sacroiliac joint from anterior at 24 h to 15 days after the injury, 2 underwent the screw internal fixation of the sacroiliac joint from posterior, and remaining 10 underwent the internal fixation by the Galveston Technique associated with the ISOLA system. The therapeutic results were analyzed. RESULTS: The follow-up of the 40 patients for 6 months to 3 years revealed that before operation 3 had a sacral plexus nerve injury, and after operation 1 patient developed perineum numbness and urinary incontinence, 1 developed claudication,3 developed posterior urethral fragmentation, and 2 developed urinary bladder rupture; however, they had a complete recovery after the reparative surgery. CONCLUSION: In treatment of the pelvic posterior ring lesions, an appropriate internal fixation can be chosen according to the type of the pelvic fracture, applicability of internal fixation, condition of the patient,equipment available, and the doctor's experience.

[The clinical effect of bipolar long-stem prosthetic replacement on the treatment of comminuted intertrochanteric fracture of hip in the elderly osteoporotic patients].

OBJECTIVE: To evaluate the clinical effect of bipolar long-stem prosthetic replacement on the treatment of comminuted intertrochanteric fracture of hip in the elderly osteoporotic patients. METHODS: From March 2000 to August 2003, 18 patients who were more than 72 years old with comminuted intertrochanteric fracture were treated with bipolar long-stem prosthetic replacement. There were 8 males and 10 females (aged from 72 to 91). Fractured fragments of large trochanter and minor trochanter should be preserved during the operation so that the fragments can be fixed with steel wires and insertion of artificial femoral head. The surgical approach and operative technique, the average course of treatment in hospital, the average time to ambulate with full-weight bearing on the operated limb after the operation, complication, and mortality were observed. RESULTS: All patients were followed up 6 to 28 months (16.2 months on average). The average course of stay at hospital was 16 days. The average time to ambulate was 32 days. The incidence of the pain of the hip joint was one-eighteenth, and one patient due to another disease was unable to walk without using two crutches one month after the surgery. The mortality of the patients was one-eighteenth one year after the surgery. CONCLUSION: Bipolar long-stem prosthetic replacement for the treatment of comminuted intertrochanteric fractures in the elderly osteoporotic patients proves to be a suitable alternative. Patients have better prognosis, early full-weight bearing, rapid rehabilitation, and fewer complications.