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Determination of Pb isotopes in melt inclusions by Laser Ablation -Multiple Collector-Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICP-MS) is limited to samples formed later than Mesozoic because U and Th signals are not monitored. In this study, Pb isotopic compositions of two reference glasses and ancient melt inclusions which have undergone significant U-Th decay are determined by LA-MC-ICP-MS. The effect of the U/Pb and Th/Pb analytical errors on the calculation of initial Pb isotopic ratios was also evaluated. In the experiment USGS NKT-1G is used as the external calibrant and a standard-sample-standard bracketing method is used to correct instrument drift and mass bias. Analytical precisions of 208Pb/206Pb and 207Pb/206Pb of USGS standards, BHVO-2G and TB-1G, are better than 0.30% (2RSD) and both agree within 0.30% of the preferred values. However, 232Th/206Pb and 238U/206Pb ratios are highly variable and yield an external precision of 5%. Error propagation calculations indicate that the ages of the samples have significant effects on the errors of the initial lead isotopic ratios. For Phanerozoic samples that are earlier than 540 Ma, even the differences between the measured 232Th/206Pb and 238U/206Pb ratios and the real values reach 10%, yet the age-corrected initial lead isotopic ratios are still within 0.80% deviations relative to the real values. Therefore, the proposed method in this study can determine the lead isotopic compositions of melt inclusions in samples from Cenozoic to Paleozoic, expanding the geological application.

Compared to the traditional strontium isotope analytical method, a micro-sample strontium isotope system study can reveal the heterogeneity of analyzed samples and is widely used in various fields of geology, such as crust-mantle interaction, genesis and evolution of magmas, open magma systems, tracing provenance of sedimentary basin and climate research. Accurate measurement of Rb-Sr isotopic ratios is the premise to apply Sr isotope in these research fields. Two detailed and widely used analysis methods for micro-sample Sr isotope measurement are microdrilling-TIMS/MC-ICPMS and LA-MC-ICPMS. These two methods have different advantages and disadvantages in sample preparation, interference correction and measurement in mass spectrometry. The greatest advantage of microdrilling-TIMS/MC-ICPMS is that this technique can acquire high quality data (external precision is better than 100×10-6, 2SD). However the tedious chemical separation is very time-consuming (about 10 days) and the chemical procedure blank must be critical to low level. The large sampling depth (100-2000 μm) and diameter (200-2000 μm) reduce the spatial resolution. However, with chemical separation this method can effectively measure samples with high Rb content. Simple sample preparation and fast analysis are the most outstanding advantages of LA-MC-ICPMS which can analyze lots of samples in a much shorter time than that of microdrilling-TIMS/MC-ICPMS. The laser spot size is mainly from 60 to 300 μm. Based on Sr contents in samples, the method of LA-MC-ICPMS improved spatial resolution, compared to microdrilling-TIMS/MC-ICPMS technique. However, without chemical separation, many kinds of interferences (e.g. Rb, Ca, Kr and REEs) hinder this technique to obtain high quality data (external precision is about 200×10-6, 2SD and accuracy is about 150×10-6). LA-MC-ICPMS is only suitable for high Sr and low Rb samples, instead of samples with high content of interferences. Further studies are required for the microdrilling-TIMS/MC-ICPMS method to improve the efficiency of chemical separation, also microdrilling technology with increasing of spatial resolution by reducing spot diameter and depth. Meanwhile, a better solution for interferences of Kr, Rb and REEs is needed for LA-MC-ICPMS in order to improve precision and accuracy of high interference samples. Instrumental sensitivity improvement is also needed to satisfy Sr isotope measurement for samples with relative low Sr content.

In this paper, the unsteady characteristics of tip leakage flow in axial fans with circumferential skewed blades were investigated at off-design conditions using wall pressure test. The static pressure fluctuations near blade tip were captured at off-design conditions by using pressure sensors mounted on casing wall. From the measured results, instantaneous characteristics of tip leakage flow in circumferential skewed fans were analyzed. Based on the measurement results, as the flow rate decreases, the broadband frequency components of tip leakage flow tend to increase in the low frequency domain. The forward-skewed blade is found to be effective in controlling tip leakage flow to expand from blade leading edge to tail edge, the TLF component of the BSK rotor propagates more fast than that of FSK rotor. The instability of tip leakage flow under off-design conditions is controlled by circumferential skewed blades. [ABSTRACT FROM AUTHOR]

This paper used numerical methods to investigate the flow field around wind turbine airfoil S809 and the airfoil with micro tab at 95% chord at the pressure side neat the trailing edge. The adaptive SST turbulence model was chosen to analyze the detailed flow field of the two airfoils under different angles of attack. The effect of the micro tab was brought out, and then the lift arising mechanism of the micro tab was presented. The results showed that the lift arising mechanism of the micro tab lied on the change of Kutta condition of the airfoil. The micro tab made the stagnation point move to the end of the micro tab, which made the aerodynamic profile and circulation increased. Meanwhile, the micro tab only availed at the normal working condition. [ABSTRACT FROM AUTHOR]

PURPOSE: To rapidly reconstruct a three-dimensional numerical model of the human upper airway and investigate the relationship between anatomical structures with airflow distribution by using the computational fluid dynamics. METHODS: A three-dimensional model of the human upper airway was reconstructed based on computed tomographic images of a healthy volunteer's skull. Numerical simulation of the upper airway airflow was performed by using computational fluid dynamics (CFD)method. RESULTS: A three-dimensional model of the human upper airway including nasal cavity, pharynx and larynx was reconstructed rapidly. A detailed anatomical structure and velocity distribution characteristics of airflow was obtained and a large velocity gradient in nasal valve area, nasopharynx, up and downstream of epiglottis was found. CONCLUSIONS: The model has good simulation of upper airway. Numerical simulation results provide the basic trend of airflow of the upper respiratory tract. The numerical model meets the needs of computational fluid dynamics analysis, and provide data control and research foundation for pathologic upper airway airflow numerical simulation. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No. 08DZ2271100) and Shanghai Leading Academic Discipline Project(Grant No.T0202). [ABSTRACT FROM AUTHOR]

Objective: To investigate the clinical effect of modified suspension reduction method combined with percutaneous vertebroplasty in the treatment of osteoporotic thoracolumbar compression fractures., Methods: From February 2020 to October 2021, 92 patients with thoracolumbar osteoporotic compression fracture were treated by percutaneous vertebroplasty. According to different treatment methods, they were divided into the observation group and the control group. The observation group was treated with modified suspension reduction and then percutaneous vertebroplasty, while the control group was treated with percutaneous vertebroplasty alone. The observation group (47 cases), including 20 males and 27 females, the age ranged from 59 to 76 years old with an average of (69.74±4.50) years old, fractured vertebral bodies:T 10 (2 cases), T 11 (7 cases), T 12 (19 cases), L 1 (14 cases), L 2 (5 cases);the control group(45 cases), including 21 males and 24 females, the age ranged from 61 to 78 years old with an average of (71.02±3.58) years old, fractured vertebral bodies:T 10 (3 cases), T 11 (8 cases), T 12 (17 cases), L 1 (12 cases), L 2 (5 cases);The leakage of bone cement were observed, the visual analogue scale (VAS), Oswestry lumbar dysfunction index (ODI), anterior vertebrae height (AVH), Cobb angle of kyphosis and the amount of bone cement injected before and after operation were recorded and compared between the two groups., Results: All patients were followed up, ranged from 6 to10 with an average of (8.45±1.73) months. Two patients ocurred bone cement leakage in observation group and 3 patients in control group. AVH of observation group increased ( P <0.05) and Cobb angle of injured vertebrae decreased ( P <0.05). Cobb angle of injured vertebrae and AVH of the control group were not significantly changed ( P >0.05). Cobb angle of injured vertebrae of the observation group was lower than that of control group ( P <0.05) and AVH was higher than that of the control group ( P <0.05). In the observation group, VAS before operation and 1 week, 3 and 6 months after operation respectively were(7.32±1.05) scores, (3.56±1.18) scores, (1.83±0.67) scores, (1.27±0.34) scores, and ODI were(40.12±14.69) scores, (23.76±10.19) scores, (20.15±6.39) scores, (13.45±3.46) scores. In the control group, VAS before operation and 1 week, 3 and 6 months after operation respectively were(7.11±5.26) scores, (3.82±0.68) scores, (1.94±0.88) scores, (1.36±0.52) scores, and ODI were(41.38±10.23) scores, (25.13±14.22) scores , (20.61±5.82) scores, (14.55±5.27) scores . The scores of VAS and ODI after operation were lower than those before operation ( P <0.05), but there was no significant difference between the two groups ( P <0.05)., Conclusion: Modified suspension reduction method combined with PVP surgery for osteoporotic thoracolumbar compression fractures has achieved good clinical results, which can effectively relieve lumbar back pain, restore vertebral height, correct kyphosis, improve lumbar function and patients' quality of life.

Oral squamous cell carcinoma (OSCC) is a common malignant tumor in the oral and maxillofacial region. At present, the treatment of OSCC is mainly based on surgical oriented comprehensive sequence therapy, especially the triple therapy of surgery, radiotherapy, and chemotherapy. However, the overall five-year survival rate is relatively low. Therefore, researching the pathogenesis and treatment methods of OSCC is important. The immune checkpoint of programmed death receptor-1 (PD-1) and programmed death receptor-1 ligand (PD-L1) have been the focus of research in recent years. Several studies have shown that the high expression of PD-1/PD-L1 in most OSCC microenvironments may contribute to the immune escape of tumors. In this study, the research status of immune checkpoint of PD-1/PD-L1 and its relevant inhibitors in OSCC were reviewed.

In order to study the purifying effect of combined floating bed constucted by salinity plant Suaeda salsa and microorganisms on the slightly salt-alkaline water, blank floating bed A, S.salsa floating bed B, microbes floating bed C and S.salsa + microorganisms combined floating bed D were established, and slightly salt-alkaline eutrophic water body (pH 8.5-9.0, salinity 5‰-7‰) was purified under continuous flow conditions in the laboratory. Results showed that the removal rates of total nitrogen, total phosphorus, permanganate index by S.salsa floating bed were 32.5%, 14.3% and 28.2%, respectively. And the removal rates of total nitrogen, total phosphorus and permanganate index by S.salsa + microorganisms combined floating bed D which installed artificial medium with microorganisms reached 70.5%, 34.7% and 70.8%, respectively, of which the removal rates of total nitrogen, total phosphorus and permanganate index by microbial units were 37.7%, 21.6% and 44.5%, respectively. Synergies removal rates of nitrate nitrogen and total nitrogen by S.salsa + microorganisms combined floating bed were 12.2% and 0.3%, but there was no synergy in the process of removing ammonia nitrogen, total phosphorus and permanganate index, which indicated that the synergies of S.salsa and microorganisms in the combined floating bed were suppressed in slightly salt-alkaline environment. The high-throughput sequencing technique was adopted to analyze the microbial community in the floating bed C and D, which indicated that the abundance and diversity of microbial community in the combined floating bed were higher, and this was consistent with the result of the higher removal rate of the flotation bed D. Principal component analysis showed that the microbial degradation was a major factor in reducing the concentration of pollutants. This study provided a guide for the using of floating bed in purifying slightly salt-alkaline eutrophic water bodies in coastal area.

This study focused on the characterization and the health risk assessment of heavy metals in the dust of Hefei City, China. Samples were collected from fifty two sampling points covering six land-use types. Most of the sites were impervious ground such as residential, commercial, industrial, educational and traffic areas, as well as public landscapes and city squares. Concentrations of Zn, Pb, Cu, Cd and Cr were measured to investigate their distribution and evaluate their risk to human health. The US EPA Health Risk Assessment Model was employed to evaluate the carcinogenic and non-carcinogenic risks of heavy metals to child and adult, respectively. The results showed that concentrations of Cd and Zn were 46 and 37 times higher than soil background values, respectively. The concentrations of Cu and Pb were 3-5 times, and Cr concentration was 1.5 times higher than the soil background values of Anhui Province. The carcinogenic risk indexes of Cr and Cd were 3.22 x 10(-7) and 2.26 x 10(-9), respectively, which were lower than the soil management standard of the US EPA, i.e. 1.0 x 10(-6). The total non-carcinogenic hazard index of the five metals for adults was only 0.212, but for children it reached to 1.259 and exceeded the safety threshold value (1.0), suggesting that the adverse health impact on children exposure to metals in urban dusts were relatively serious in Hefei. The ingestion of dust particles was the major exposure pathway for health risk. The orders of non-carcinogenic hazard indexes of land-use types and heavy metals were industrial area > public landscapes and city squares > commercial area > educational area > residential area > traffic area, and Pb > Cr > Zn > Cd > Cu, respectively.

Purpose: To rapidly reconstruct a three-dimensional numerical model of the human upper airway and investigate the relationship between anatomical structures with airflow distribution by using the computational fluid dynamics., Methods: A three-dimensional model of the human upper airway was reconstructed based on computed tomographic images of a healthy volunteer's skull. Numerical simulation of the upper airway airflow was performed by using computational fluid dynamics (CFD) method., Results: A three-dimensional model of the human upper airway including nasal cavity, pharynx and larynx was reconstructed rapidly. A detailed anatomical structure and velocity distribution characteristics of airflow was obtained and a large velocity gradient in nasal valve area, nasopharynx, up and downstream of epiglottis was found., Conclusions: The model has good simulation of upper airway. Numerical simulation results provide the basic trend of airflow of the upper respiratory tract.The numerical model meets the needs of computational fluid dynamics analysis, and provide data control and research foundation for pathologic upper airway airflow numerical simulation.

Objective: To determine the contents of NOS and endogenous CO in the penile corpus cavernosum of Wistar rat models of hyperthyroid and hypothyroid, to detect the effects of thyroid hormone and endogenous CO on rat penile erection, and to further investigate the influence of thyroid hormone on human penile erection., Methods: Fifty 3-month-old male Wistar rats were randomly and equally divided into 5 groups: a hyperthyroid, a hyperthyroid treatment, a hypothyroid, a hypothyroid treatment and a control group. The contents of NOS and CO were detected by ultraviolet spectrophotometry., Results: Compared with the controls, the content of NOS was significantly decreased in both the hyperthyroid and the hypothyroid groups (P < 0.01), even lower in the latter than in the former (P < 0.01), and so was the content of CO (P < 0.01), lower in the former than in the latter (P < 0.01). After treatment, the levels of NOS and CO were both elevated in either the hyperthyroid or the hypothyroid group, with no significant difference from that of the controls (P > 0.05)., Conclusion: The contents of NOS and CO in the penile corpus cavernosum decrease with the imbalance of thyroid hormones, but return to normal once the imbalance is corrected. Under the same conditions, hypothyroid inflicts more damage on penile erection than hyperthyroid.