Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas-Solid Jet in Flat Flame Burner

Ammonia as a fuel to partially or completely replace fossil fuels is one of the effective ways to reduce carbon dioxide, and the research on ammonia coal cocombustion is of great significance. The combustion characteristics of ammonia are very different from those of pulverized coal, resulting in the ignition and emission characteristics of ammonia and pulverized coal gas flow that is different from traditional pulverized coal flame. In this paper, the effect of pulverized coal concentration in coal and ammonia mixed combustion jet on the ignition distance and gas-phase components at different positions of the jet flame were studied experimentally on the flat flame burner, and the conditions of ignition and ignition stability of coal and ammonia gas-solid fuel were expounded. It was found that the ammonia mixed with pulverized coal changed the temperature field of the flat flame burner and therefore the ignition characteristics of the jet were changed. The ignition delay time at the same jet speed was positively correlated with the pulverized coal concentration, but when the pulverized coal concentration continued to decrease, the influence on the ignition delay time gradually became smaller. The composition of coal ammonia gas-solid fuel changed the heat transfer path and share during combustion, and finally, the flame temperature was negatively correlated with the concentration of pulverized coal. Therefore, the reduction of the pulverized coal concentration was conducive to the stable combustion of coal ammonia mixed fuel. When HAB = 100 mm, the conversion rate of fuel N to NOx per unit mass of coal ammonia mixture increased with the increase of pulverized coal concentration. The NOx production amount first increased and then decreased with the increase of pulverized coal concentration, and the amount of N2O and NO2 decreased rapidly with the increase of HAB. The proportion of NOx in NO exceeded 94%, which was conducive to achieving low nitrogen combustion of coal and ammonia gas-solid fuel. In general, the O2 concentration in the ammonia coal jet flame decreased, the flue gas temperature, and NOx and CO generation increased after mixing ammonia, and the optimal pulverized coal concentration in this experiment was 0.41 kgc/kga (mass ratio of pulverized coal to the sum of N2 and NH3).

Molecular mechanism of human ISG20L2 for the ITS1 cleavage in the processing of 18S precursor ribosomal RNA

The exonuclease ISG20L2 has been initially characterized for its role in the mammalian 5.8S rRNA 3' end maturation, specifically in the cleavage of ITS2 of 12S precursor ribosomal RNA (pre-rRNA). Here, we show that human ISG20L2 is also involved in 18S pre-rRNA maturation through removing the ITS1 region, and contributes to ribosomal biogenesis and cell proliferation. Furthermore, we determined the crystal structure of the ISG20L2 nuclease domain at 2.9 Å resolution. It exhibits the typical αβα fold of the DEDD 3'-5' exonuclease with a catalytic pocket located in the hollow near the center. The catalytic residues Asp183, Glu185, Asp267, His322 and Asp327 constitute the DEDDh motif in ISG20L2. The active pocket represents conformational flexibility in the absence of an RNA substrate. Using structural superposition and mutagenesis assay, we mapped RNA substrate binding residues in ISG20L2. Finally, cellular assays revealed that ISG20L2 is aberrantly up-regulated in colon adenocarcinoma and promotes colon cancer cell proliferation through regulating ribosome biogenesis. Together, these results reveal that ISG20L2 is a new enzymatic member for 18S pre-rRNA maturation, provide insights into the mechanism of ISG20L2 underlying pre-rRNA processing, and suggest that ISG20L2 is a potential therapeutic target for colon adenocarcinoma.

Structural and biochemical insights into the interaction mechanism underlying HORMAD1 and its partner proteins

The mammalian HORMA domain-containing protein 1 (HORMAD1) regulates DNA mismatch repair and homologous recombination (HR) repair in many cancers. Here, we show that the structure of human HORMAD1 adopts a self-closed conformation and displays an intra-molecular HORMA domain-closure motif interaction mode. Structural and biochemical data suggest that the interaction modes of the peptide motifs from HORMAD2 and MCM9 with HORMAD1 are highly similar to that of HORMAD1 own closure motif. The peptide motifs from diverse binding partners of HORMAD1 share a conserved Ser-Glu-Pro sequence. Additionally, structural comparison unveiled the HORMA-peptide motif interaction mode diversity among HORMA-containing proteins. Finally, cell-based assays revealed that this HORMA-closure motif interaction pattern contributes to DNA mismatch repair and is required for HORMAD1-dependent HR repair. Together, our results provide structural and biochemical insights into the common theme and functional plasticity of the HORMA domain-containing protein family, and also reveal a universal regulation mechanism for HORMAD1.

Apelin-13/APJ system delays intervertebral disc degeneration by activating the PI3K/AKT signaling pathway

OBJECTIVE

To study the effect of Apelin-13/APJ system on intervertebral disc degeneration and its mechanism.

PATIENTS AND METHODS

This study detected the expression of APJ in human intervertebral disc tissue with varying degrees of degeneration. IL-1β is used to stimulate the degeneration of nucleus pulposus cells. We used recombinant human Apelin-13 and Ala13 to activate and inhibit the APJ receptor, respectively. The inhibitor LY294002 was used to inhibit the PI3K/AKT signaling pathway. We studied the effects of Apelin-13/APJ system on nucleus pulposus cells and its mechanism by Western blot, RT-PCR, and so on.

RESULTS

APJ is lowly expressed in the nucleus pulposus of patients with a high degree of degeneration. IL-1β stimulates the nucleus pulposus cells and reduces the expression of APJ in nucleus pulposus cells. Recombinant human Apelin-13 reduces the degradation of nucleus pulposus extracellular matrix, promotes proliferation, and reduces the levels of apoptosis and inflammation. In addition, the Apelin-13/APJ system increases the expression of PI3K and AKT and activates the PI3K/AKT signaling pathway.

CONCLUSIONS

Apelin-13/APJ system activates PI3K/AKT signaling pathway activity, reduces the degradation of nucleus pulposus extracellular matrix, promotes proliferation, and reduces the level of apoptosis and inflammation, thus delaying the degeneration of the intervertebral disc.

[A comparative study on the construction methods of animal models of aortic arch dissection]

Objective: To compare the effectiveness and safety of different methods to construct animal models of aortic arch dissection (AAD), and explore safe and effective methods for constructing AAD animal models. Methods: Twenty-four healthy mongrel dogs were divided into 4 groups by random number table (n=6). Group A: Venous incision needle high pressure water flow impact method; Group B: Venous incision needle non-high pressure water flow impact method; Group C: Transarterial sheath non-high pressure water flow impact method; Group D: Two-way balloon expansion combined with elastase perfusion method. Imaging examinations were performed immediately and 7 days after operation, aortic tissue biopsy and pathological staining were performed 15 days after operation to observe the formation of AAD. The operation time, aortic blood flow block time, model construction success rate, dissection tear length, postoperative survival rate and survival time of four groups of experimental dogs were collected to compare the effectiveness and safety of different construction methods. Results: There were no significant difference of the gender, age and weight between four groups of experimental dogs (all P>0.05). The operation time of four groups of experimental dogs were (111.6±8.0), (168.0±17.4), (164.4±13.9), (202.8±21.5)min, and the difference was statistically significant (F=39.973, P<0.001). The operation time of group A was significantly lower than group B, C and D (all P<0.001). The aortic blood flow block time of four groups of experimental dogs were (5.2±1.8), (19.6±3.8), (20.6±3.9), and (18.6±3.0) min, and the difference was statistically significant (all P<0.001). The aortic blood flow block time of group A was significantly lower than group B, C and D (F=27.598, P<0.001). The four groups of experimental dogs had 5, 5, 4, and 1 model were successfully constructed, respectively, and the difference was statistically significant (P=0.008). The successful rate of model construction in group A was significantly higher than that in group D (P=0.040). The dissection tear length of four groups were (14.4±3.0), (11.3±4.2), (7.0±2.3), (4.7±0.6) cm,and the difference was statistically significant (F=8.103, P=0.003). The dissection tear length of group A was significantly longer than group C, D (all P<0.05). The postoperative survival time were 15.0(10.0, 15.0), 5.0(3.0, 10.0), 3.5(1.5, 4.8), 10.0(2.8, 15.0) days, and the difference was statistically significant (χ²=7.825,P=0.036). The postoperative survival time of group A was significantly higher than group B, C (all P<0.05). There was no significant difference in the survival rate of the four groups (P=1.000). The pathological staining results showed that the elastic fiber at the tearing point of AAD was destroyed, and the elastic fiber on the outer wall of the false cavity was over-stretched, which was consistent with the pathological changes of aortic dissection. Conclusion: Transvenous incision needle high-pressure water flow impact modeling method is easy to operate. The aortic blood flow block time is short, the dissection tear length is wide, and the postoperative survival time is long, can be used as the preferred method of animal AAD model construction.

Genetic polymorphisms in IL1B predict susceptibility to steroid-induced osteonecrosis of the femoral head in Chinese Han population

The purpose of this research was to examine if the IL1B gene polymorphism has impact on the risk of steroid-induced ONFH in Chinese population. We found that IL1B rs1143630 decreased the SANFH's risk and IL1B rs2853550 increased the risk of steroid-induced ONFH. So, we guess that IL1B gene influences the genetic susceptibility of steroid-induced ONFH.

INTRODUCTION

Genetic polymorphisms in IL1B gene could be related in the pathogenesis of osteonecrosis. Discusses on the relationship between the IL1B gene and steroid-induced osteonecrosis of the femoral head (steroid-induced ONFH) is still less in Chinese Han population. So, in this research, we want to examine whether the IL1B gene polymorphism has impact on the risk of steroid-induced ONFH in Chinese population.

METHODS

A total of 286 steroid-induced ONFH patients and 441 controls were recruited, and seven SNPs (rs2853550, rs1143643, rs3136558, rs1143630, rs1143627, rs16944, and rs1143623) in IL1B gene were selected; unconditional logistic regression analysis was used to research the influence on the risk of steroid-induced ONFH. Functional annotations of IL1B variants were performed by RegulomeDB and HaploReg.

RESULTS

rs1143630 (A>C) in the IL1B gene decreased the risk of steroid-induced ONFH in the allele model (OR = 0.69, 95%CI 0.51-0.93, p = 0.014). Further genetic model analyses found that IL1B rs2853550 AG genotype increased the risk of steroid-induced ONFH compared with the people who are carriers of the IL1B rs2853550 GG genotype (OR = 1.69, 95%CI 1.16-2.46, p = 0.012). In the dominant model, IL1B rs1143630 GG-GT genotype decreased the risk of steroid-induced ONFH (OR = 0.62, 95%CI 0.44-0.87, p = 0.0051). And further haplotype analysis was performed, while the result was not significant. Using RegulomeDB and HaploReg, rs2853550 is likely to affect TF binding, any motif and DNase peak.

CONCLUSIONS

We guess that IL1B gene influences the genetic susceptibility of steroid-induced ONFH.

[Clinical application and observation of injectable modified sodium hyaluronate gel filler for facial cosmetic surgery]

Objective: To evaluate the clinical effect of injectable modified sodium hyaluronate gel filler in the treatment of facial profile modification and rejuvenation. Methods: A total of 125 patients who received facial injection of hyaluronate gel from October 2013 to October 2015 were collected. The patients included 62 cases for rhinoplasty, 28 for chin augmentation, 20 for nasolabial fold correction and 15 for lacrimal groove correction. The post-operation results, satisfaction survey and adverse reaction were observed. Results: All the injected positions improved immediately, and the instant average satisfaction score was 9.3±0.7, followed by 8.1±0.7 after 3 months, 6.9±0.8 after 6 month and 5.2±0.8 after 1 year. Thirty cases exhibited swelling, 5 cases bruised, and they all recovered within one week. Conclusions: Sodium hyaluronate is effective and stable in the treatment of facial contour modification and rejuvenation.

[Clinical value of bendopnea in chronic heart failure patients with reduced left ventricular ejection fraction]

Objective: To explore the clinical value of bendopnea in chronic heart failure patients with reduced ejection fraction (HFrEF). Methods: According to the existence of bendopnea or not, a total of 192 consecutive chronic heart failure patients with HFrEF admitted to our department from January 2014 to January 2016 were divided into the bendopnea group and non-bendopnea group. Subgroup analysis was performed in the subgroups with various bendopnea symptoms appearance time (0-10 s, 11-20 s and 21-30 s). The relationship between bendopnea and left ventricular ejection fraction (LVEF), 6-minute walking distance (6-MWD), NT-proBNP and NYHA classification were analyzed. Results: Bendopnea was confirmed in 74 out of 192 (38.54%) cases with HFrEF, and the average time of symptoms appearance was (8.62±2.29) s. LVEF and 6-MWD values were significantly lower in the bendopnea group than those in the non-bendopnea group (both P<0.05). The NT-proBNP level and the prevalence of patients with NYHA grade Ⅳ were significantly higher in the bendopnea group than those in the non-bendopnea group (both P<0.05). There were significant difference on LVEF, 6-MWD, NT-proBNP and patients with NYHA grade Ⅳ in bendopnea patients with various bendopnea symptoms appearance time (all P<0.05) and shorter bendopnea symptoms appearance time was related to severe symptoms and signs of chronic heart failure. Conclusion: The incidence rate of bendopnea is high in patients with HFrEF, and which is related closely to the cardiac function and shorter bendopnea symptoms appearance time is related to severe symptoms and signs of chronic heart failure in HFrEF patients.

Effects of phenol on metabolic activities and transcription profiles of cytochrome P450 enzymes in Chironomus kiinensis larvae

Phenol, also known as carbolic acid or phenic acid, is a priority pollutant in aquatic ecosystems. The present study has investigated metabolic activities and transcription profiles of cytochrome P450 enzymes in Chironomus kiinensis under phenol stress. Exposure of C. kiinensis larvae to three sublethal doses of phenol (1, 10 and 100 µM) inhibited cytochrome P450 enzyme activity during the 96 h exposure period. The P450 activity measured after the 24 h exposure to phenol stress could be used to assess the level (low or high) of phenol contamination in the environment. To investigate the potential of cytochrome P450 genes as molecular biomarkers to monitor phenol contamination, the cDNA of ten CYP6 genes from the transcriptome of C. kiinensis were identified and sequenced. The open reading frames of the CYP6 genes ranged from 1266 to 1587 bp, encoding deduced polypeptides composed of between 421 and 528 amino acids, with predicted molecular masses from 49.01 to 61.94 kDa and isoelectric points (PI) from 6.01 to 8.89. Among the CYP6 genes, the mRNA expression levels of the CYP6EW3, CYP6EV9, CYP6FV1 and CYP6FV2 genes significantly altered in response to phenol exposure; therefore, these genes could potentially serve as biomarkers in the environment. This study shows that P450 activity combined with one or multiple CYP6 genes could be used to monitor phenol pollution.

Fourier-transform Raman and infrared spectroscopic analysis of 2-nitro-tetraphenylporphyrin and metallo-2-nitro-tetraphenylporphyrins

The Fourier-transform Raman (FT-Raman) and infrared (FT-IR) spectra of 2-nitro-tetraphenylporphyrin (2-NO(2)-TPP), nickel-2-nitro-tetraphenylporphyrin (Ni-2-NO(2)-TPP), zinc-2-nitro-tetraphenylporphyrin (Zn-2-NO(2)-TPP) and copper-2-nitro-tetraphenylporphyrin (Cu-2-NO(2)-TPP) were acquired for the first time and carefully assigned and discussed. The effects of a beta-NO(2) group and the influence of the central metal on the molecular symmetry and vibrational spectra of the porphyrin macrocycle were also examined. The bands at 1323-1339, 1516-1526 and 961-971 cm(-1) were attributed to the symmetric and asymmetric stretching vibration of the NO(2) group and to the stretching vibration of the C(beta)-N bond, respectively, which connects the NO(2) group with the beta-carbon of the porphyrin macrocycle. These bands can act as a marker to distinguish beta-NO(2) TPPs from other beta-substituent TPPs. Cu-2-NO(2)-TPP has a C(4nu) molecular symmetry, which is different from those of Ni-2-NO(2)-TPP and Zn-2-NO(2)-TPP, i.e. D(4h).

Fourier-transform Raman and infrared spectroscopic analysis of dipyrrinones and mesobilirubins

The Fourier-transform Raman (FT-Raman), infrared (FT-IR), and UV-visible absorption spectra of four dipyrrinones and two mesobilirubins have been investigated in the solid state and in CH2Cl2 solutions. A detailed spectral analysis, assignment and discussion of these spectra are presented. The bands at 1735-1738, 1691-1707 and 1359-1377 cm(-1) which were assigned to the stretching vibrations of the C-O-C and C-O-H and symmetric deformation of C-H bonds, respectively, can act as a marker to distinguish the compounds of this class. The striking differences between the spectra of the compounds suggest that mesobilirubin XIIIalpha is tending to adopt as ridge-tile conformation, rather than linear conformation.

Hemispherical variations in seismic velocity at the top of the Earth's inner core

Knowledge of the seismic velocity structure at the top of the Earth's inner core is important for deciphering the physical processes responsible for inner-core growth. Previous global seismic studies have focused on structures found 100 km or deeper within the inner core, with results for the uppermost 100 km available for only isolated regions. Here we present constraints on seismic velocity variations just beneath the inner-core boundary, determined from the difference in travel time between waves reflected at the inner-core boundary and those transmitted through the inner core. We found that these travel-time residuals-observed on both global seismograph stations and several regional seismic networks-are systematically larger, by about 0.8 s, for waves that sample the 'eastern hemisphere' of the inner core (40 degrees E to 180 degrees E) compared to those that sample the 'western hemisphere' (180 degrees W to 40 degrees E). These residuals show no correlation with the angle at which the waves traverse the inner core; this indicates that seismic anisotropy is not strong in this region and that the isotropic seismic velocity of the eastern hemisphere is about 0.8% higher than that of the western hemisphere.

[Changes of genomic density polymorphism and quantitative expression of complement receptor type 1 in patients with liver diseases]

OBJECTIVE

To study the changes of genomic density polymorphism and quantitative expression of complement receptor type 1 (CR1) on erythrocytes in patients with liver diseases.

METHODS

Polymerase chain reaction (PCR) and Hind III restriction enzyme digestion and the quantitative assay of erythrocytic CR1 were used.

RESULTS

The spot mutation rate (25.0% approximately 30.3%) of erythrocyte CR1 density gene in patients with liver diseases was not significantly different with that of healthy individuals (28.0%). The amount of erythrocytic CR1 in patients with liver diseases, except for those with normal liver function, was significantly lower than that of healthy individuals (t=10.44, P<0.0001). The quantitative expression of erythrocytic CR1 in decompensated cirrhosis was obviously lower than that of compensated cirrhosis (t=2.21, P<0.05).

CONCLUSION

Defective expression of CR1 in liver diseases is acquired through central and/or peripheral mechanisms. It is very important to study the quantitative expression in the evaluation of the development of liver diseases.

Fourier-transform Raman and infrared spectroscopic analysis of novel biliverdin compounds

The vibrational spectroscopy of novel biliverdin compounds were studied by Fourier-transform Raman (FT-Raman) and infrared (FT-IR) spectroscopy. The effects of type, length and position of substituents at C(8) and C(12) or C(1) and C(19) of tetrapyrroles on FT-Raman and FT-IR spectra of these compounds, are discussed. The marker bands are developed in order to distinguish between etiobiliverdin and mesobiliverdin.