Search

In order to investigate the influence of the deflector layout on the performance of mine-used main fan diffuser, the RNG k-ε turbulence model was applied to numerical simulation of the internal flow fields under three inlet velocity conditions with and without deflector. The influence of the central angle and starting angle of the deflector on the performance of the diffuser was investigated. The results show that for the diffuser without deflector, a serious flow accumulation phenomenon exists inside the flow field, which restricts the performance improvement of the diffuser; when the center angle of the deflector is small, the larger the starting angle of its installation is, the higher the diffusion efficiency of the diffuser under the three inlet velocities considered, however the secondary flow due to the uneven pressure on the upper and lower sides of the deflector head appears at some starting angles, which results in an increase in flow losses. As the center angle of the deflector increases, the flow accumulation inside the diffuser improves gradually, and the secondary flow also gradually weakens. When the center angle reaches 60°, the diffusion efficiency is the highest.

Disordered heap and unreasonable disposition of livestock manure in Erhai Lake Basin was the main pollution resource to Erhai. There exist problems in middle temperature biogas engineering, such as low gas production, unstable and easy to crusting. In order to control the farming wastes’ pollution and select the suitable middle temperature biogas engineering operation parameters for the anaerobic fermentation process in Erhai Lake basin, taking the dairy manure as sampling, this study investigated the effects of temperature, substrate concentration and inorganic stimulating factors on the middle temperature anaerobic fermentation efficiency. What’s more, the amount of trace elements was optimized with response surface method in the paper. The experimental conditions were 600 mL total volume of fermentation broth, 8% total solids content with a 30 days fermentation period. The single factor experiment of fermentation temperature selected three levels of 30, 35 and 45℃ for comparison. The results showed that the proportions of gas production in the first 20 days were respectively 93.7%, 93.5% and 95.3% accounted for the total gas production. The total gas production were respectively 0.187, 0.239 and 0.158 L/g at the end of the fermentation period. Thus, under the condition of fermentation temperature of 35℃, the gas production was greater than that at 30 and 45℃, it was conductive to the production of volatile fat acids (VFA), the reuse of methane bacteria, and the 4 kinds of microbial populations (aerobic acid-producing bacteria, anaerobic acid-producing bacteria, anaerobic cellulose decomposing microorganisms, methanogenic bacteria) were more than that at 30 and 45℃ in each stage of the fermentation. Therefore, fermentation temperature at 35℃ had a highest biogas production rate and a most proportion rate of functional microorganisms. The single factor experiment of substrate concentration selected 4 levels of 0, 10%, 20%, 30% and 40% for comparison. The total gas production were respectively 10 060, 10 622, 10 064, 9 358 and 8 558 mL at the end of the fermentation period. Therefore, the inoculation amount of 10% had the maximum total gas production, and the higher inoculation amount with a faster inoculation fermentation start-up speed. Meanwhile, the addition of inorganic stimulating factor can promote the whole fermentation process. It was investigated by the central composite experimental and response surface regression analysis. The results showed a fine effect between real values and predicted values of central composite experimental used quadratic polynomial fitting regression method. Response surface figures of Ni2+-Co2+, Fe2+-Ni2+ and Fe2+-Co2+ effects on accumulated biogas production were shown according to the central composite experimental results. And Ni2+-Co2+ and Fe2+-Ni 2+ did not have interaction，while Fe2+-Co2+ have interaction. Verification experiments were conducted, the results showed that the error between 3 parallel experimental values and predicted values was only 3.6%. Thus, the optimum concentrations was 5.00 mg/L Fe2+, 21.40 μg/L Ni2+, 28.82 μg/L Co2+. Under these conditions, it had a best gas production effect. Compared with the anaerobic fermentation system without addition of Fe2+, Ni2+ and Co2+, the biogas production was increased by 30%. The results will provide a basis for the normal operation of the rural farming manure anaerobic fermentation project in Erhai Lake basin. [ABSTRACT FROM AUTHOR]

Objective: The nasal swell body（NSB） consists of the nasal septal cartilage, nasal bone, and swollen soft tissue, all of which are visible during endoscopic and imaging examinations. Although the function of the NSB remains uncertain, there is evidence to suggest that it plays a vital role in regulating nasal airflow and filtering inhaled air. Based on anatomical and histological evidence, it is hypothesized that the NSB is indispensable in these processes. This study aims to investigate the impact of NSB on nasal aerodynamics and the deposition of allergen particles under physiological conditions. Methods: The three-dimensional （3D） nasal models were reconstructed from computed tomography （CT） scans of the paranasal sinus and nasal cavity in 30 healthy adult volunteers from Northwest China, providing basis for the construction of models without NSB following virtual NSB-removal surgery. To analyze the distribution of airflow in the nasal cavity, nasal resistance, heating and humidification efficiency, and pollen particle deposition rate at various anatomical sites, we employed the computed fluid dynamics（CFD） method for numerical simulation and quantitative analysis. In addition, we created fully transparent segmented nasal cavity models through 3D printing, which were used to conduct bionic experiments to measure nasal resistance and allergen particle deposition. Results: ①The average width and length of the NSB in healthy adults in Northwest China were （12.85±1.74） mm and （28.30±1.92） mm, respectively. ②After NSB removal, there was no significant change in total nasal resistance, and cross-sectional airflow velocity remained essentially unaltered except for a decrease in topical airflow velocity in the NSB plane. ③There was no discernible difference in the nasal heating and humidification function following the removal of the NSB; ④After NSB removal, the deposition fraction（DF） of Artemisia pollen in the nasal septum decreased, and the DFs post-and pre-NSB removal were（22.79±6.61）% vs （30.70±12.27）%, respectively; the DF in the lower airway increased, and the DFs post-and pre-NSB removal were（24.12±6.59）% vs （17.00±5.57）%, respectively. Conclusion: This study is the first to explore the effects of NSB on nasal airflow, heating and humidification, and allergen particle deposition in a healthy population. After NSB removal from the healthy nasal cavities: ①nasal airflow distribution was mildly altered while nasal resistance showed no significantly changed; ②nasal heating and humidification were not significantly changed; ③the nasal septum's ability to filter out Artemisia pollen was diminished, which could lead to increased deposition of Artemisia pollen in the lower airway., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Objective: To investigate the causal relationship between the minimum cross-sectional area of nasal cavity and nasal resistance. Methods: Thirty transparent detachable 3D printing nasal cavity models were made. The airway was completely blocked with sealing material at different anatomical sections. Then ventilatable nasal drainage tubes with different cross-sectional areas were used to pass through the nasal cavity. Nasal resistance was measured. SPSS was used for statistical analysis. Results: ①The postoperative nasal resistances of patients and 3D printing nasal cavity models were （0.38±0.15）Pa· s/mL and （0.39±0.02）Pa· s/mL respectively. There was no statistical difference between the two groups.The preoperative nasal resistance of patients was （0.56±0.09）Pa· s/mL, and the postoperative nasal resistance of the models was significantly descreased by 31% compared with preoperative nasal resistance of the patients, with statistically significant difference（ P <0.05）. ②When the ventilatable nasal drainage tubes with a cross-sectional area of 3.14 square millimeters was located in the the upper part of common meatus and the nasal valve area, the nasal cavity is moderately blocked, and the nasal resistances were （1.80±0.30） times and （2.02±0.36） times of that before the obstruction respectively. When the ventilatable nasal drainage tube was located in the lower part of common meatus,the nasal resistance was （1.68±0.28） times of that before the obstruction. ③When the ventilatable nasal drainage tubes with a cross-sectional area of 6.28 square millimeters and were located in the lower part of common meatus, the upper part of common meatus and nasal valve area, the nasal resistances were （1.44±0.23） times, （1.50±0.25） times and （1.60±0.27） times of those before obstruction, respectively. ④When the ventilatable nasal drainage tubes with a cross-sectional area of 9.42 square millimeters were located in the above areas, nasal ventilation was nearly normal without obvious nasal obstruction. The nasal resistances were （1.17±0.18） times, （1.26±0.21） times and （1.33±0.24） times of those before obstruction, respectively. ⑤The nasal resistance was statistically significant correlated with the cross-sectional area of the ventilation tubes and the obstruction sites. The correlation coefficients were -0.895 and 0.339, respectively （ P <0.05）. Conclusion: ①3D printing can quickly and accurately replicate anatomical structure of the nasal cavity, and can be used as a research method for quantifitative measurement of nasal resistance. ②The minimum cross-sectional area of nasal cavitiy is the main determinant of nasal resistance. ③The obstruction site is the secondary determinant of nasal resistance. When the degree of nasal obstruction is the same , the nasal resistance in the nasal valve area is sightly higher than that in the common meatus., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Objective: To explore the characteristics of three-dimensional motion of lumbar instability segmental in vivo under physiological weight bearing so as to establish three-dimensional diagnostic criteria for degenerative lumbar segmental instability (DLSI)., Methods: Eight patients aged 29-65 years with DLSI at L3/4 were studied as instability group (L3/4), 9 patients aged 51-60 years with DLSI at L4/5 as instability group (L4/5) and 10 healthy volunteers aged 26-51 years as normal group. Three-dimension (3D) reproductions by matching lumbar spine models were reconstructed from thin-section computed tomography scans. Spine motions were then reproduced by matching lumber spine models and images from dual fluoroscopic imaging system (DFIS). The models were matched to the osseous outlines of images from two orthogonal views to determine the SD position of vertebrae for each pose. From local coordinate systems at end plates, the motion of cephalad vertebrae relative to cauddal vertebrae was calculated for vertebrae levels., Results: The motion pattern at L3/4 was altered . During flexion-extension, migration was significantly larger than normal group along sagittal axis (P < 0.05); rotation was significantly larger than normal group along vertical axis; migration was significantly smaller than normal group along vertical axis; during left-right twisting, rotation was significantly larger than normal group along vertical axis (P < 0.05). The motion pattern at L4/5 was also altered . During flexion-extension, migrations was significantly larger than normal group along sagittal axis (P < 0.05). During left-right twisting, migration and rotation were significantly smaller than normal group along vertical axis (P < 0.05). Rotation was significantly larger than normal group along sagittal axis. During left-right bending, rotation was significantly larger than normal group along sagittal axis (P < 0.05)., Conclusion: Lumbar instability segments were significantly different compared with normal lumbar segments. And lumbar instability segments (at L3/4) were also different from lumbar instability segments (at L4/5). Different three-dimensional diagnostic criteria should be formulated for different lumbar instability segments.

Objective: To study the ultrastructure change and cell apoptosis in the olfactory mucosa of rats suffering from chronic sinusitis, and aim to elucidate the possible mechanism and provide a novel concept of therapy approach to olfactory disease caused by chronic sinusitis., Method: Light microscope and transmission electron microscope were used to observe the ultrastructure changes in the olfactory mucosa of 20 rats suffering from chronic sinusitis and that in 20 cases of normal olfactory mucosa. By the method of TUNEL (TdT-mediated dUTP nick end labeling), we studied the apoptosis index (AI) in the olfactory mucosa of 20 rats suffering from chronic sinusitis and that in 20 cases of normal olfactory mucosa., Result: (1) Observation by transmission electron microscope: In the olfactory epithelium of the rats group suffering from chronic sinusitis, the ultrastructure of the olfactory epithelium showed some abnormal changes: Olfactory epithelium cells showed a variety of degeneration ornecrosis, the olfactory epithelium were quite disorganized. Supporting cell nuclei were oval, the nuclei of the cell aggregated as the plaque and fringe collection, the density of cytoplasm decreased. Surface microvillus of the olfactory cells reduced and disappeared, part of the karyolemma defected like morphology change about cell apoptosis. Inflammatory cells infiltrated. Basement membrane was exposed and cells were quite disorganized. Olfactory gland cells were prismatic, cell spaces were widen and secretion increased in the cavosurface. In the olfactory mucosa of normal group, the ultrastructure of olfactory epithelium showed some normal changes: Olfactory epithelium were quite regularity, supporting cells and olfactory cells were radial arrangement, basement membrane were integrated, the structure of olfactory gland were completed, microvirus were in richet in cavosurface and slight of serositim were in the cavosurface; (2) The apoptosis index (AI) in the olfactory epithelium of the rats group suffering from chronic sinusitis was higher than that in normal group (P < 0.05)., Conclusion: There is a ultrastructural change from the surface to the inner of olfactory mucosa in rats suffering from chronic sinusitis. There is notable apoptosis in the olfactory epithelium and propria lamina of rats suffering from chronic sinusitis.

Objective: To observe the changes in the morphology and distribution of substance SP and calcitonin-gene related peptide nerves in the anterior pituitary of scalded rats., Methods: The rats inflicted 30% TBSA degree scalding of the back were employed as the model. The SP and CGRP peptide nerve fibres in the anterior pituitary were observed by immunohistochemistry staining during different postburn time points: 1, 2, 6, 10, 12, 24 and 72 postburn hours (PBHs). The areas of coverage of SP and CGRP nerve fibers were determined respectively in the anterior pituitaries by image analysis., Results: The morphology of the two peptide nerve fibers exhibited obvious changes under microscope. The numbers of SP and CGRP nerve fibers increased by 85.7% and 60.5%, respectively at 1 PBH when compared with those in control group. Moreover the varicosities and branches of the nerve fibers in scalded rats increased obviously at 1 PBH and decreased sharply at 2 PBH, bouncing back to near normal level at 24 PBH. reaching image analysis revealed that the changes in the areas of coverage of two peptide nerve fibers were correlated positively with each other. The basic trends of the changes were an increase at 1 PBH, a decrease thereafter, reaching the lowest level at 12 PBH with a rebound later., Conclusion: The morphology and distribution of SP and CGRP nerve fibers of anterior pituitary in scalded rats exhibited obvious change after injury. Therefore, they might be involved in the functional modulation of systemic stress.