Study on the secondary oxidation behavior and microscopic characteristics of oxidized coal gangue.

Spontaneous combustion of coal gangue (CG) hills has caused varieties of secondary disasters that seriously endanger the ecological environment of the world. The emission law of index gases and their oxidation kinetics during the secondary oxidation process of CG with different ranks of oxidation were studied by using the temperature programmed device and online mass spectrometer (MS). Fourier transform infrared spectroscopy (FTIR) was used to reveal the changes of the CG internal active functional groups. The results showed that the energy required for the combustion of CG with low rank of pre-oxidation was significantly lower than that of the raw sample. However, as the oxidation rank increased, due to amounts of volatile components were released in the process of oxidation reaction, the CG in the combustion process of the emission of index gases and its oxygen consumption rate gradually reduced; the rapid oxidation stage shifted to the direction of the high temperature. In this study, the risk of spontaneous combustion of CG after oxidation at 80 â„ƒ under 3% oxygen concentration was the strongest. The results of this paper are of great guiding significance for exploring the spontaneous combustion characteristics of CG hills and their prevention by traditional covering method.

Treatment of tibial traumatic osteomyelitis with negative pressure closure drainage combined with open bone grafting or bone migration and its effect on the levels of CRP, TNF-α and IL-6 in the serum.

Objective: To observe the effect of negative pressure closure drainage combined with open bone grafting or bone migration in the treatment of tibial traumatic osteomyelitis. Methods: Eighty-six (86) cases of tibial traumatic osteomyelitis admitted to Hospital of the Chinese people's Liberation Army from September 2017 to September 2018 were randomly divided into control group and observation group, forty-three (43) cases each. Debridement, open bone grafting or bone migration was given to the control group.The observation group was treated with negative pressure closed drainage on the basis of the control group. In addition, the serum components such as CRP, TNF-α, IL-6 of the control group and observation group were detected respectively after surgery. Results: Observation group granulation cover wound, fracture healing time was shorter than the control group, fracture healing rate was better than the control group, the difference has statistical significance (P<0.05). By comparing serum CRP, TNF-α, IL-6 levels before and after treatment in the two groups, it was found that the observation group was lower than the control group (P<0.05, respectively). Serum CRP, TNF-α, IL-6 levels were significantly (P<0.05). Conclusion: The treatment of tibial traumatic osteomyelitis with negative pressure closure drainage combined with open bone grafting or bone displacement has a good effect on fracture healing and is worth popularizing.

Piezoelectric Effect and Ignition Characteristics of Coal Mine Gob Roof Collapse.

Existing studies of coal self-ignition and impact frictional sparks do not provide valid support for the analysis of ignition sources in all cases of methane explosions in the gob. In this paper, the explosion in the gob of the Renlou coal mine is used to investigate the piezoelectric effect and ignition characteristics of roof collapse in identifying a new ignition source of gas explosion. Experimental and theoretical analyses conclude that the piezoelectric effect is produced by quartz, which is the main constituent of the roof sandstone. During the loading process, the piezoelectric effect and compressive strength are key factors in the gathering of free charges on rock tips. During rupture, the rock tip retains a large number of charges, forming a ″point-surface″ effect, which triggers an electron avalanche accompanied by an orange-yellow spark lasting over 22 ms, far exceeding the ionization energy and ignition induction period of methane-air mixtures. The piezoelectric effect and compressive strength of the rock cause the generation of electrical sparks, which is the ignition source of the explosion in the gob of Renlou mine II7322.

Three-dimensional printing of gastro-floating tablets using polyethylene glycol diacrylate-based photocurable printing material.

Extruded three-dimensional (3D) printing based on photocurable materials has shown good application prospects in the medical field. This has been attributed to the operational aspect that can be performed at room temperature and the high mechanical strength of the extrudate and final product. However, the commonly used photocurable polymer, polyethylene glycol diacrylate (PEGDA), has a low viscosity and exhibits a long crosslinking time. Therefore, additives are added to improve the printability of the extrudate. In this study, various hydrogels were used to improve the mixing uniformity and rheological behavior of PEGDA-based printing materials. Printing accuracy and mechanical strength were evaluated to optimize print material composition and process parameters. Hydroxypropyl methylcellulose K100M was found to improve the shear thinning and self-supporting properties of printing materials, which were essential for printability. Although the storage modulus of the photocured material proportionally increased with curing time in the range of 20-80 s, the minimal layer time of the 3D samples remained at 65 s, ensuring interlayer adhesion. Gastro-floating tablets with different infill densities were printed to illustrate the application of 3D extrusion printing in personalized medicine. The weight, crushing strength, and floating time were regulated by the infill density of the models. Overall, this study demonstrates that extrusion printing with a photocurable material is an easy way to prepare customized oral preparations with complex internal structures and tunable properties.

Spatial Distribution and Asymmetry of Surface Electromyography on Lumbar Muscles of Soldiers with Chronic Low Back Pain.

This study investigated spatial distribution and asymmetry of surface electromyography on lumbar muscles during a sustained contraction in soldiers with and without chronic low back pain. Twenty healthy soldiers and twenty chronic low back pain (CLBP) soldiers had performed the Sorensen test with a duration of 60 seconds. The corresponding muscle fatigue, spatial distribution, and the asymmetry of muscle activity over bilateral paraspinal lumbar regions were measured by the high-density surface electromyography (HDsEMG). The paired and independent samples t-tests were performed to compare the degree of muscle fatigue and asymmetry. The repeated-measures analyses of variance (ANOVA) were used to compare spatial distribution between groups and muscle fatigue. The baseline characteristics of soldiers between groups were comparable. CLBP soldiers had significantly less muscle fatigue on both sides of erector spinae compared to healthy ones. The spatial distribution was significantly associated with the group factor but independent of muscle fatigue. In addition, the asymmetry of erector spinae activity in the CLBP soldiers was significantly higher than the healthy one. In conclusion, uneven spatial distribution and asymmetry of lumbar muscle activity play significant roles in CLBP patients. The HDsEMG could be used as an objective method in distinguishing the function of the erector spinae between healthy individuals and CLBP patients during 1 min sustained contraction.

Long noncoding RNA LINC00858 promotes osteosarcoma through regulating miR-139-CDK14 axis.

Long noncoding RNAs (lncRNAs) have been identified to modulate the tumorigenesis of human cancers. The in-depth of lncRNAs on human osteosarcoma oncogenesis is still ambiguous. In present study, functional and mechanism experiments were conducted to investigate the role of long intergenic non-protein coding RNA 00858 (LINC00858) on human osteosarcoma tumorigenesis. Results demonstrated that LINC00858 expression was significantly upregulated in both osteosarcoma tissues and cell lines. Mechanism assays presented that LINC00858 silencing significantly repressed osteosarcoma cells' proliferation and invasion in vitro, and inhibited the tumor growth in vivo. In further experiments, LINC00858 was identified to sponge miR-139 to form RNA-induced silencing complex (RISC) using luciferase reporter assay and RNA immunoprecipitation (RIP). Besides, CDK14 was validated to be the target protein the miR-139. Rescue experiments confirmed the role of LINC00858/miR-139/CDK14 pathway on osteosarcoma cells' phenotype. In summary, these data prove that LINC00858/miR-139/CDK14 axis promotes the tumorigenesis of osteosarcoma, providing a new mechanism or target for osteosarcoma.

LncRNA DICER1-AS1 promotes the proliferation, invasion and autophagy of osteosarcoma cells via miR-30b/ATG5.

Osteosarcoma is a prevalent primary malignant tumor and long non-coding RNAs (lncRNAs) have been validated to modulate the osteosarcoma tumorigenesis. In present study, our research team investigates the role of a novel identified lncRNA DICER1-AS1 on the tumor progression and autophagy. Results showed that lncRNA DICER1-AS1 was up-regulated in osteosarcoma cells using microarray analysis and RT-PCR. Cellular functional experiments revealed that DICER1-AS1 knockdown suppressed the proliferation, migration, invasion and autophagy of osteosarcoma cells in vitro. Besides, DICER1-AS1 knockdown inhibited the protein expression levels of ATG5, LC3-II and Beclin 1, suggesting the inhibition on the autophagy of osteosarcoma cells. Moreover, miR-30b was verified to target 3'-UTR of DICER1-AS1 and ATG5 using bioinformatics tools and luciferase reporter assay or RNA-immunoprecipitation (RIP). Western blot showed that ATG5 protein expression was decreased in DICER1-AS1 knockdown and miR-30b mimics transfected cells, while increased in miR-30b inhibitor transfected cells, presenting a negative correlation with miR-30b and a positive correlation with DICER1-AS1. Finally, xenograft assay in vivo indicated that DICER1-AS1 knockdown inhibited the osteosarcoma tumor growth and protein expression level of ATG5. In summary, all the results conclude that DICER1-AS1 regulates the proliferation, invasion and autophagy of osteosarcoma via miR-30b/ATG5 axis, providing a novel insight for osteosarcoma tumorigenesis.

Adaptation of muscles of the lumbar spine to sudden imbalance in patients with lower back pain caused by military training.

OBJECTIVE: This study aims to investigate the effects of sudden load changes (expected and unexpected imbalance) on the activity of muscles of the lumbar spine and their central motor control strategy in military personnel with or without chronic low back pain (LBP). DESIGN: Bilateral sudden imbalance was examined (2 × 2 factorial design). SETTING: The 117th PLA Hospital, Hangzhou, China PARTICIPANTS: Twenty-one male subjects with lower back pain and 21 male healthy control subjects were active members of the Nanjing Military Region land forces. OUTCOME MEASURES: Independent variables: LBP vs. healthy controls and imbalance anticipation (expected and unexpected imbalance). DEPENDENT VARIABLES: rapid reaction time (RRT) and intensity of rapid reaction (IRR) of bilateral lumbar (L3-L4) erector spinae (ES), lumbar (L5-S1) multifidus (MF), and abdominal external oblique muscles. Results Under expected or unexpected sudden imbalance conditions, subjects with LBP demonstrated significantly greater IRR than healthy controls in ipsilateral and contralateral ES and MF, respectively (P < 0.05 for all). IRR of contralateral ES was significantly larger than that of the ipsilateral ES. A significant group effect of RRT of both ipsilateral and contralateral ES muscles and a significant time expectation effect on RRT of contralateral MF muscles were also observed. RRT of the contralateral ES muscles was significantly lower than that of the ipsilateral ES muscles (P < 0.001). CONCLUSIONS: Sudden imbalance prolonged RRT of selected trunk muscles in patients with chronic LBP. The activation amplitude increased. The results may provide a theoretical basis for a study on the pathogenesis of chronic LBP.

Treatment of unstable intertrochanteric fractures with percutaneous non-contact bridging plates.

We reviewed medical records of patients with unstable intertrochanteric fractures (AO/OTA type 31-A2, A3) treated with percutaneous non-contact bridging (NCB) plates and with gamma nails and compared operative data and outcomes. Fifty-two patients received NCB plates (27 males and 25 females; median age, 77.0 years) and 36 received gamma nails (15 males and 21 females; median age, 77.0 years). Fluoroscopy time in the NCB plate group was 34.0 s (IQR: 30.0, 37.5), and in the gamma nail group was 45.0 s (IQR: 39.0, 51.5, p < 0.001). Hospital stay in the NCB plate group was significantly shorter than the gamma nail group (15.0 days [IQR: 13.0, 16.5] vs. 17.0 days [IQR: 14.0, 19.0], respectively; p = 0.004). Harris hip scores were similar between the groups at 6 months and 1 year postoperatively. The percutaneous NCB plate provides satisfactory results for the treatment of unstable intertrochanteric fractures.

Prevalence of low back pain among soldiers at an army base.

BACKGROUND: Low back pain (LBP) is a major medical and social problem among working populations and is associated with high medical expense, loss of productivity, and disability. The aim of this study is to investigate the prevalence of LBP among soldiers and evaluate the possible causative factors in military training. The results may provide an insight into changes needed in military training that will reduce the occurrence of LBP among soldiers. METHODS: A cross-sectional survey was conducted in a group of young soldiers in China to estimate the prevalence of LBP and evaluate possible causative factors in military training. RESULTS: The survey was distributed to 1659 soldiers, of whom 1624 responded. LBP was reported by 425 of the 1624 (26.2%) soldiers. The prevalence of LBP was higher in the armored force (51.3%) than in the artillery (27.5%) or infantry (11.9%). A multivariate logical regression analysis identified night training, 5 km cross-country race, and grenade-throwing training as military training risk factors for LBP. CONCLUSIONS: The relatively high incidence of LBP among soldiers was related to night training, 5 km racing, and grenade throwing. Modifications in these training methods should enhance the health of recruits and lower the incidence of LBP.

Influence of distal tibiofibular synostosis on ankle function.

OBJECTIVE: To study the influence of distal tibiofibular synostosis on ankle function. METHODS: From October 1998 to October 2004, a total of 281 consecutive patients underwent operations because of ankle fractures or distal fractures of the tibia and fibula. Distal tibiofibular synostosis occurred after operation in 8 patients. The duration of follow-up averaged 20.6 months (14-44 months). The ankle function was assessed on the basis of functional rating system described by Mazur.(1) RESULTS: According to Mazur's ankle evaluation system, 4 patients achieved an excellent result, 2 a good result and 2 a fair result. The dorsiflexion of the synostosis ankle reduced by 8.26 degrees as compared with that of the contralateral ankle, and there was little influence on the plantar flexion. All the patients had a normal gait. CONCLUSION: The distal tibiofibular synostosis after the operation of ankle fractures or distal fractures of the tibia and fibula usually gives rise to few symptoms and needs no specific treatment.

Treatment of displaced radial head fractures by internal fixation with absorbable pins.

OBJECTIVE: To study the effect of internal fixation with absorbable pins on treatment of displaced radial head fractures. METHODS: From May 1999 to May 2004, 16 patients with displaced radial head fractures (Mason types II and III) were treated with internal fixation by absorbable pins. The duration of follow-up averaged 22.6 months (12-58 months). The outcome was assessed on the basis of elbow motion, radiographic findings and the functional rating score delineated by Broberg and Morrey. RESULTS: All fractures healed within 10 months without avascular necrosis of radial head. The mean elbow flexion loss was 15 degrees (0 degrees-35 degrees), and pronation and supination decreased by 10 degrees (0 degrees-30 degrees) on average compared with those of the contralateral elbow. Five patients had an excellent result, 6 a good result, and 3 a fair result according to the criteria of Borberg and Morrey. CONCLUSIONS: Internal fixation with absorbable pins is an effective method in treating displaced radial head fractures. It can maintain the biomechanical stability of forearm, improve the elbow function and avoid second operation.