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25 models are designed according to the orthogonal table, to study the comprehensive relationship between heat transfer and sealing characteristics in straight-through labyrinth seals with different geometrical parameters. The experimental investigations are carried out at different pressure ratios of 1.2, 1.3, 1.4, 1.6, 1.8. The results show that different geometry parameters brought obvious different influence on both leakage efficiency and heat transfer characteristics, and in which the parameters (H, c,β) have the most significant influence on leakage efficiency, and heat transfer characteristics under different pressure ratios, whose small changes in size can lead to performance optimization in leakage and heat transfer. The geometrical parameters always show consistent influence on leakage efficiency and heat transfer characteristics, while heat transfer characteristics show larger vibration with the increase of pressure ratio.

ObjectiveTo explore the prevalence and influencing factors of osteoporosis and to analyze the relationship between biochemical indicators and bone mineral density among Yugur menopausal women and adult women (aged 20 – 80 years) in Gansu province.MethodsUsing stratified cluster sampling, we recruited 960 Yugur female residents aged 20 – 80 years in Su′nan Yugu Autonomous County, Gansu province and conducted a questionnaire survey, laboratory test and physical examination including calcaneal bone mineral density detection in the women during July – August 2016. Multivariate logistic regression was used to analyze associates of osteoporosis prevalence and multivariate linear regression was adopted to assess the relationship between biochemical indicators and bone density.ResultsFor the 929 participants with complete information, the crude and standardized prevalence rate of osteoporosis was 27.64% and 23.53% and those were 13.99% and 12.78% for the menopausal participants, respectively. The prevalence rate of osteoporosis increased significantly with age among all the participants (χ2 = 114.576) and the menopausal participants (χ2 = 31.664) (both P < 0.05). The results of logistic regression analysis revealed that for menopausal women, the influencing factors of osteoporosis prevalence included marital status, menopause duration, and grip strength; while for adult women, the influencing factors included age, education, fracture history, and grip strength. Alkaline phosphatase was reversely correlated with bone mineral density significantly in menopausal women (β = – 0.003) and in the women aged 20 – 80 years (β = – 0.004) (both P < 0.05).ConclusionAmong Yugur menopausal women and 20 – 80 years old women in Gansu province, the prevalence rate of osteoporosis is relatively low and increases with age; the main risk factors of osteoporosis prevalence include age, duration of menopause and fracture history; alkaline phosphatase is a predictor for bone density reduction in the women.

Reactions of the semi-rigid N,N′-bis(3-pyridyl)terephthalamide (L) with divalent metal salts in the presence of dicarboxylic acids afforded [Cd(L)0.5(1,2-BDC)(H2O)]n (1,2-H2BDC = benzene-1,2-dicarboxylic acid), 1, {[Cd(L)1.5(1,3-BDC)(H2O)]·5H2O}n (1,3-H2BDC = benzene-1,3-dicarboxylic acid), 2a, {[Cd(1,3-BDC)(H2O)3]·2H2O}n, 2b, {[Cd(L)0.5(1,4-BDC)(H2O)2]·H2O}n (1,4-H2BDC = benzene-1,4-dicarboxylic acid), 3, and [Cu(L)0.5(5-tert-IPA)]n (5-tert-IPA = 5-tert-butylbenzene-1,3-dicarboxylic acid), 4, which have been structurally characterized by single crystal X-ray diffraction. Complexes 1 and 3 are two-dimensional (2D) layers with the bey and the hcb topologies, and 2a and 2b are one-dimensional (1D) ladder and zigzag chain, respectively, while 4 shows a 3-fold interpenetrated three-dimensional (3D) net with the cds topology. The structures of these coordination polymers containing the semi-rigid L ligands are subject to the donor atom positions and the identity of the dicarboxylate ligands, which are in marked contrast to those obtained from the flexible bis-pyridyl-bis-amide ligands that form self-catenated nets. The luminescence of 1 and 3 and thermal properties of complexes 1, 3, and 4 are also discussed.

According to the design requirements of high-temperature combustion chamber, an advanced shaped hole structure was designed for film cooling. Numerical method was applied in this study to investigate the flow and heat transfer characteristics of shaped holes and compared with those of cylindrical holes. The influence of the forward expansion angle of shaped holes on the flow and heat transfer was studied. The results show that compared to cylindrical holes, the diffused structure of shaped holes decreases the momentum of jet flow, improves the adhesion characteristics of the cooling air film, increases the diffusion of the coolant air outflow and improves the cooling efficiency between adjacent columns of holes in the lateral direction. When the forward expansion angle increases, the expansion section induced the flow vortex, which reduces the radial velocity of coolant flow and enhances the diffusion of cooling air film both in streamwise and spanwise directions. However, as the forward expansion angle increases further, the scale of vortex inside the shaped hole grows. Too large vortex inside the shaped hole increases the coolant eject angle, which weakens the film covering effect. Additionally, the shaped hole results in an increase in lateral spreading and enhances the cooling effect between adjacent columns of the film hole. The enhancement of the film cooling characteristics is due to the change in the shape of the film hole, resulting in the enhancement of the flow vortex, which induces complicated secondary flow.

Purpose: To investigate effects and heat distribution of radiofrequency ablation (RFA) on vertebral tumors in vitro and in vivo swine experiments and its clinical application. Materials and methods: RFA was performed on the swine spine in vitro and in vivo for 20 min at 90 °C at the electrode tip, and the temperature at the electrode tip and surrounding tissues were recorded. Clinical application of ablation combined with vertebroplasty was subsequently performed in 4 patients with spinal tumors. Results: In the in vitro study, the mean temperature at the front and ventral wall of the spinal canal was 50.8 °C and 43.6 °C, respectively, at 20 mm significantly greater than 37.7 °C and 33.7 ± 1.7 °C, respectively, at 10 mm ablation depth. The coagulative necrosis area was significantly (P

A series of Co(II), Ni(II) and Cu(II) coordination polymers and dinuclear metallocycles containing 4-aminopyridine (4-ampy) and benzenedicarboxylate ligands, {[M(4-ampy)2(1,4-BDC)]·H2O·CH3CH2OH}n (M = Ni, 1a; Co, 1b, 1,4-H2BDC = benzene-1,4-dicarboxylic acid), {[Ni2(4-ampy)4(1,3-BDC)2]·H2O·CH3CH2OH}n (1,3-H2BDC = benzene-1,3-dicarboxylic acid), 2, [M2(4-ampy)4(1,2-BDC)2] (M = Ni, 3a; Co, 3b, 1,2-H2BDC = benzene-1,2-dicarboxylic acid), [Co(4-ampy)2(1,3-BDC)]n, 4, {[Cu(4-ampy)2(1,4-BDC)] CH3CH2OH}n, 5a, and {[Cu(4-ampy)2(1,4-BDC)]·H2O}n, 5b·H2O, are reported, which were hydrothermally prepared and structurally characterized by using single crystal X-ray diffraction. Complexes 1a and 1b are isomorphous 1D zigzag chains, while 2 displays a concave–convex chain and 3a and 3b are dinuclear metallocycles that differ in the boding modes of the 1,2-BDC2− ligands, forming a 3D and a 2D supramolecular structures with the pcu and sql topologies, respectively. Complex 4 exhibit a 1D helical chain and complexes 5a and 5b·H2O are 1D linear and zigzag chains, in which the Cu2-1,4-BDC2− units adopt the cis and trans configurations, respectively. A novel irreversible structural transformation due to cis→trans isomerization of the Cu2-1,4-BDC2− units was observed in 5b⋅H2O and 5a upon water adsorption of the desolvated product of 5b·H2O.

One-pot solvothermal reactions of 2-aminopyridine, triethylorthoformate and sodium hydroxide with CuX (X = Br, and I) in dimethylformamide (DMF) and methanol (MeOH) afforded extended metal chains based on the linear tetracopper units, {[Cu4Br2(Dpyf)2]·DMF}n, 1, and [Cu4I2(Dpyf)2]n, 2, which were structurally identified by X-ray crystallography. Complexes 1 and 2 present closed-shell Cu(I)–Cu(I) interactions that are supported by formamidinate ligands, resulting in a face-to-side configuration and a face-to-face configuration, respectively, for the tetranuclear units. Complexes 1 and 2 represent the first example of one-dimensional (1D) coordination polymers that are based on linear tetracopper units. Moreover, complexes 1 and 2 can be regarded as copper(I) halide aggregates with the unique Cu4Br2 2+ and Cu4I2 2+ cations extending into a 1D zigzag chain and a looped chain, respectively. Complexes 1 and 2 show broad emissions at 570 and 549 nm, respectively, which can most probably be ascribed to 3d(Cu) → π* metal to ligand charge transfer. Reversible crystal-to-crystal transformation and luminescence change were observed for complex 1 upon solvent exchange, which can be regarded as a potential luminescent sensor for selective detection of water and methanol. [ABSTRACT FROM AUTHOR]

Finger seal is a type of compliant seal configuration that has superior sealing performance compared with conventional labyrinth seals and brush seals. However, complex working conditions lead to leakage, thermal gradient and deformation, which can be more serious for a contacting finger seal due to frictional heating. In this paper, a leakage and thermal performance analysis method coupled with porous media and a real structure model was developed to numerically simulate the leakage, heat transfer and thermal deformation characteristics of a contacting finger seal. The method innovatively established a porous media fluid dynamics and heat transfer model and modified the frictional heating model by introducing the concept of a friction work conversion ratio. Then, the thermal deformation of the fingers was calculated on the basis of pressure and temperature results by using the thermal-stress module of ANSYS Workbench. The results show that the leakage analysis porous media model has good calculation accuracy and most of the fluid leaks through the finger foot, while the pressure drops mainly in this field. The highest finger temperature occurs at the downstream side of the contact surface between the finger foot and the rotor. The largest thermal deformation of each laminate occurs at the finger foot toe and increases slightly along the flow direction. Additionally, the largest relative circumferential thermal deformation can reduce the gap between the fingers by approximately 5%, which is beneficial for reducing leakage. It is suggested to increase the seal inner diameter at the finger foot toe but decrease it at the finger foot heel during the design process to decrease wear and leakage. [ABSTRACT FROM AUTHOR]

Finger seal is a new type of compliant seal configuration, which is an important part of an aero-engine and its accessory systems. It has superior sealing performance compared with conventional labyrinth seals and a lower manufacturing cost than brush seals. However, numerical simulation of the leakage characteristics of an entitative finger seal structure are very difficult to implement, because the finger laminates are in close contact with one another and the radial deformation of the fingers caused by interference between seal and rotor as well as the centrifugal and thermal expansion of the rotor can change the geometric structure of seal. The published leakage analysis models of finger seal ignore the leakage throughout the interstices between fingers or finger laminates. In view of this, the authors propose an anisotropic porous media model for leakage analysis of finger seal. The model considers the effects of the seal structure parameters, upstream and downstream axial pressure differences and the fit status between seal and rotor. First, the equations of the model and their parameters were obtained by theoretical derivations, while the correction factors were determined based on experiment leakage data in the literature. Second, the accuracy of the model was validated by calculating the leakage of a known seal structure in the literature and comparing these results with the experimental data. At last, a comparison between the anisotropic and isotropic porous media model is carried out. The results of the validation examples show that the model can simulate the leakage of finger seal very well with the errors between numerical results and experimental data are less than 10% for two-thirds of the data points. [ABSTRACT FROM AUTHOR]

Background: Clinical trials assessing the effects of salt substitutes on blood pressure (BP) have reported mixed results. Objectives: A meta-analysis of randomized controlled trials was conducted to evaluate the effect of salt substitutes on BP, including systolic BP (SBP) and diastolic BP (DBP). Design: Studies were identified via systematic searches of the PubMed, Embase, Cochrane Library, Wanfang Data, and the China National Knowledge Infrastructure databases through December 2013. Random-effects models were used to estimate pooled mean differences in SBP and DBP. Results: Six cohorts from 5 articles (1 trial enrolled 2 cohorts for independent intervention) consisting of 1974 participants were included. Pooled results showed that salt substitutes had a significant effect on SBP (mean difference: -4.9 mm Hg; 95% CI: -7.3, -2.5; P < 0.001) and DBP (mean difference: -1.5 mm Hg; 95% CI: -2.7, -0.3; P = 0.013). Significant heterogeneity was found for both SBP (I² = 76.7%) and DBP (I² = 65.8%). The sensitivity analysis indicated that the pooled effects of salt substitutes on SBP and DBP were robust to systematically dropping each trial. Furthermore, no evidence of significant publication bias from funnel plots or Egger's tests (P = 0.17 and 0.22 for SBP and DBP, respectively) was found. Conclusion: This meta-analysis showed that salt-substitution strategies are effective at lowering SBP and DBP, which supports a nutritional approach to preventing hypertension. [ABSTRACT FROM AUTHOR]

Eur J Clin Invest 2010; 40 (8): 669–677 Background A mutation in MEF2A (myocyte enhancer factor-2A) had been reported to be the first gene linked directly to coronary artery disease (CAD). However, an opposing opinion was proposed recently that MEF2A mutations are not a common cause of sporadic CAD. In this study, we screened exon 11 of the MEF2A gene in people of the Han nationality in China and finished some functional analysis of found variations. Materials and methods A gene structural investigation of MEF2A in 257 CAD patients and 154 control individuals were developed in this study. Subsequently, typical MEF2A variations were cloned and expressed in HeLa or 293T cell line to illustrate whether found structure changes could influence the main biological functions of these proteins. At last, another set of gene structural screen was initialized to get more reliable conclusions. Results Totally 16 different variations were detected in exon 11 of this gene in the first set of gene structural screen. By cloning and expressing typical MEF2A proteins in cultured cells, all the acquired MEF2A variations had transcriptional activation capabilities and subcellular localization patterns similar to those of the wild-type protein. Further larger scale genetic screening also revealed that the reported genetic variations of MEF2A did not differ significantly between CAD patients and healthy controls. Conclusions Our results reveal that structural changes of exon 11 in MEF2A are not involved in sporadic CAD in the Han population of China. [ABSTRACT FROM AUTHOR]

Abstract Objective  The aim of this study was to investigate long-term immunological changes after the treatment of Graves’ disease (GD) with thyroid arterial embolization and the effect of thyroid arterial embolization on the body’s immunological functions. Materials and methods  Forty-one patients with clinically and laboratorily ascertained GD were treated with thyroid arterial embolization and followed up for 3–54 months following embolization. Prior to embolization and at 1, 3, 6, 12, and 36 months following embolization, thyroid autoimmune antibodies were tested respectively, including thyroid stimulating antibody (TSAb), thyrotropin antibody (TRAb), thyroglobulin antibody (TGAb), and thyroid microsomal antibody (TMAb), as well as subgroup lymphocytes of CD16+CD56+, CD19+, CD3+, CD3+CD4+ and CD3+CD8+. The autoimmune status of GD patients prior to embolization and the dynamic changes of the immunological function after embolization were analyzed. Results  The therapy of thyroid arterial embolization could effectively decrease the activity/titer and positive rate of TRAb and the ratio of CD4+/ CD8+ to normal levels at 6 months following embolization, while the ratio of CD3+CD8+ increased gradually to normal level at 1 year following embolization. In patients with recurrence, TSAb and TRAb remained at a higher level, while the rate of CD3+CD8+ and the ratio of CD4+/CD8+ were not statistically significantly different from those before embolization. Conclusion  Immunological functional disorder exists in GD patients. The treatment method of thyroid arterial embolization can effectively resume the basic immunological function to normal range while patients with recurrence have no significant improvement, suggesting that thyroid arterial embolization has an effective role in adjusting the immunological function. [ABSTRACT FROM AUTHOR]

The flow and heat transfer characteristics of a film jet inclined to different supersonic situations with a varying Mach number of the main flow were numerically investigated. In supersonic situations, complicated waves are generated by the obstacle of the film jet. In this work, extra pressure is exerted onto the film jet, causing better film attachment to the wall. The strengthening of attachment decreases mixing between the main flow and film jet, causing better film cooling. We observed multi-interfacial layered structures caused by the film jet under the complicated effect of shock waves. At the interfaces of the film jet and shock waves, additional pressure is exerted on the film towards the wall. The pressure increases as the Mach number of the main flow increases and contributes to the increased adhesion of the gas film, which causes the cooling enhancement under a supersonic condition. In the vicinity of the film hole exit, a local low pressure region is formed under the influence of the supersonic main flow. An aerodynamic convergent–divergent state was formed in the film hole, devastating the state of supersonic congestion of the film hole and further enhancing the film cooling effect. [ABSTRACT FROM AUTHOR]

Premise of the study: Microsatellite markers were developed for the aquatic plant Sagittaria trifolia var. sinensis to assess its genetic diversity and population structure. Cross-species transferability was assayed in eight congeneric species. • Methods and Results: Seventeen microsatellite markers were isolated and characterized in Sagittaria trifolia var. sinensis using Fast Isolation by AFLP of Sequence COntaining Repeats (FIASCO) protocol. Across the evaluated populations, 14 of the markers showed polymorphisms with 3 to 11 alleles per locus; the observed and expected heterozygosity ( H o and H E ) ranged from 0.0000 to 0.6364 and from 0.0000 to 0.8386, respectively. Nine of the loci were successfully amplifi ed in the congeneric species. • Conclusions: These markers will be useful for further investigation of population genetics in Sagittaria trifolia var. sinensis and related research in Sagittaria species. [ABSTRACT FROM AUTHOR]