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Fibromyalgia (FM) is a chronic nonarticular rheumatic disease mainly characterized by diffuse disseminated skeletal muscle pain, with varied symptoms including anxiety, sleep disturbance, and fatigue. Due to its unknown etiology and pathogenesis, FM is easily ignored in clinical practice, resulting in unclear diagnosis and difficult treatment. This study is aimed at investigating whether AKAP12 and RNF11 can be used as biomarkers for the diagnosis of FM and at determining their correlation with immune infiltration. The FM dataset in Gene Expression Omnibus (GEO) database was downloaded and was randomly divided into the training and test sets. Differentially expressed genes (DEGs) were screened, and functional correlation analysis was performed. Diagnostic markers of FM were screened and validated by random forest (RF). The least absolute shrinkage and selection operator (LASSO) logistic regression algorithm was then used to evaluate immune cell infiltration in the FM patients’ peripheral blood. Finally, Spearman’s rank correlation analysis was used to identify correlation between the diagnostic indexes and immune cell infiltration. A total of 69 DEGs were selected. Results indicated that AKAP12 and RNF11 can be used as diagnostic markers of FM, and CD8 + T cells might contribute in the pathogenesis of FM. In addition, AKAP12 was positively correlated with CD8 + T cells, while RNF11 was negatively correlated with CD8 + T cells. In conclusion, AKAP12 and RNF11 can be used as diagnostic indicators of FM, and CD8 + T cells may be involved in the occurrence and development of FM.

Asthma is a chronic respiratory disease characterized by airway inflammation and remodeling as well as hyper-responsiveness. Thymic stromal lymphopoietin (TSLP), which is a crucial inflammatory cytokine in immune homeostasis, consists of two isoforms, the long isoform lfTSLP and short isoform sfTSLP. The lfTSLP promotes inflammation and plays a pivotal role in asthma pathogenesis, while sfTSLP had been reported to have anti-asthma effects. Experiments have shown that lfTSLP could induce autophagy in hepatocytes. It is unknown whether lfTSLP or sfTSLP could influence autophagy and affect the progression of asthma. Using house dust mite (HDM)-stimulated airway smooth muscle cells as an in vitro model and HDM-induced asthma mice as in vivo model, we found that lfTSLP could induce autophagy and remodeling, while sfTSLP has the reverse effect. Strikingly, sfTSLP treatment in vivo reversed HDM-mediated activation of inflammation and airway remodeling, partly determined by autophagy change. These findings may help us understand the function of TSLP isoforms in the pathogenesis of asthma, and they support the use of drugs targeting sfTSLP and TSLP for asthma treatment.

In the present work, the mechanical properties of 321 stainless steel pressure equipments exposed to an accident fire in a chemical unit were investigated. The performance and microstructure of this material were described by chemical compositions analysis, tensile test, scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experiment results showed that the mechanical properties of the material were degraded. The grains on the external surface of the fracture became coarse. These results indicated that serious damage to 321 stainless steel had been induced by extreme heat of the fire and this pressure vessel could not be used anymore.

Y-branch is often used in connection between a main pipe and two branch pipes, for example, in furnace, quench boiler, nuclear parts and so on. The stress distribution in the Y-branch is very complicated because of complicated shape and complex loads on it. The stresses in the Y-branches cannot be determined by theoretical equations. Finite element method is used to analyze the stresses in the Y-branches. As an example, a Y-branch used in a high temperature furnace is calculated with ANSYS software. The temperature distribution and elastic and elastic-plastic stress fields in the Y-branch under mechanical and thermal loads are calculated. Strength, creep and fatigue of the Y-branch are evaluated based on T-1300, T-1400 of ASME Boiler and Pressure Vessel code Sec Ⅲ Div 1 Subsection NH.

Two finite element analysis models of tubesheet of shell-and-tube heat exchangers are highlighted. Traditional theory of elastic foundation model is used for tube to tubesheet interaction in model I. Pipe elements are used to represent actual interaction between tube and tubesheet in model II. By the comparison of model I and model II results, it is confirmed that the distributions of the deformations and stress intensities for both models have very little differences under complicated mechanical and thermal loads. Model I is suitable for FEA of shell-and-tube heat exchangers, because model I is enough accurate and model II is more complicated and it takes more time and memory spaces of computer. The axial forces at tube-to-tubesheet for two models are nearly the same and the axial forces generated by bending moments are very small. The elastic foundation theory of the standards of design is suitable.

This paper analyzes the interaction of coplanar semi-elliptical surface crack and embedded elliptical crack in a cylindrical pressure vessel. No numerical solution appears to be available in the literature so far for this kind of interaction. The analyzed ratios of the crack depth to crack length are 0.25, 0.5 and 1.0; the distances between two cracks are 0.5, 1.0 and 2.0. In total 54 crack configurations are analyzed and the stress intensity factors along the crack front are presented. The interaction increases the stress intensity factors along the crack fronts for both the surface crack and the embedded one, compared with the single surface crack and single embedded one. And, for the given crack dimensions, the stress intensity factors for both the surface crack and embedded crack increase with the decrease of the distance between two cracks. In the end of the text, an interpolating technique is presented for estimating the stress intensity factors for the interaction of cracks whose ratios of crack depth to crack length are different from 0.25, 0.5 and 1.0. The numerical analyses are carried out by the hybrid boundary element method.

The base and weld metals of old STFA26 (Cr9Mo) seamless alloy steel tubes, which were put into service at 570°C for 16 000 h, are investigated experimentally. The mechanical properties of the base and weld metals of old and new tubes are also examined. The results show that the properties of the STFA26 alloy tubes scarcely have deterioration in long service at 570°C and the tubes can be used in the furnace in the following service.

The behaviour of fatigue crack propagation in a high stress concentration area caused by a geometrical notch in the structure is studied. Low cycle fatigue tests in two kinds of materials and a total of six specimens of double-through cracks emanating from the edges of an elliptical hole were carried out. For reducing errors in the parameter calculation, a calculation formula for the stress intensity factor K of a finite width panel with double-through cracks emanating from the edges of a central elliptical hole is first established, and then, a large plastic zone correction method is introduced to take account of the elastic-plastic behaviour. Finite element analyses were carried out to confirm the accuracy of the formula and the method. Both the stress intensity factor K and the large plastic zone correction form of K are used as correlating parameters. The results show that the large plastic zone correction form of K developed by the present studies which successfully represents the J integral for the problem studied is a suitable parameter to explore the behaviour of fatigue crack propagation in a high stress concentration area.

In this paper, the author proposes a modified Newman-Raju solution for SIF at the nozzle corner crack of a pressure vessel. The results of fatigue crack growth at nozzle corners under cyclic internal pressure tests are demonstrated. It is found that the fatigue crack growth rate at a nozzle corner is approximately governed by the SIF in the crack tip and in engineering it can be estimated satisfactorily by Paris' law.

Considering reinforcement pad and the cylindrical shell as an integral model and a contact model, stress analysis for opening-reinforcement structures of a cylindrical shell is performed by elastic and elastoplastic FEM. By comparison of two sub-models and two material constitutive relations (elastic and elastoplastic), the stress distribution of cylindrical shell intersections by the contact model is similar to that by the integral model, but there are some differences of the stress at contact surfaces of the shell and the reinforcement pad between by the contact model and by the integral model. In general, the stress analysis of the integral model for pad reinforcement can approximately represent that of the contact model. Finite element analyses for different nozzle diameters and different oblique angles in nozzle and cylinder shell intersections are carried out. The stress distribution and the maximum stress are affected by oblique angle. But the difference of the maximum stress intensity among different diameters is small.Copyright © 2007 by ASME

The residual stresses of mismatch butt welds of a cylinder were measured by the blind-hole method before and after a vibratory residual stress relief treatment. The results show that this treatment could greatly reduce the maximal butt weld residual stress of dissimilar steel from 540MPa to 119MPa. The concentrated distributions of the first and the second principal residual stresses became gentle after the vibratory residual stress relief treatment.Copyright © 2007 by ASME

Finite element method is applied to calculate the stress distribution and the maximum stress location of the tubesheets, tubes and other parts of a tubular heat exchanger in a petrochemical plant. Comparison between FE results and TEMA results is discussed. The temperature and stress distribution of tubesheets and other important parts can be accurately calculated by FE method, also the safety margin of the parts in the heat exchanger can be clearly given by FE method. For multi-pass heat exchanger, FE method is more useful. By analyzing FE results, it is easily to know whether the stresses in exchangers are over the allowable value. Therefore, FE method is a good measure to aid heat exchanger design when standard of TEMA is used.

Tube pulling apart loads of tube-and-shell heat exchangers are very complicated, because these loads are affected by many factors, such as, tube to tubesheet joint structure, pressure, and temperatures. The tubes may break or be fouled during the service, which will result in change of tube metal temperatures and affect pulling loads. Some tubes may be pulled out from the tubesheet because of too much high tube pulling apart loads and the heat exchanger cannot be operated normally. Depending on the different flow passes of the fluid and the temperature change in the service, the tube pulling loads for several cases with different temperature distribution are calculated and analyzed for a heat exchanger using finite element (FE) method. The results show that the pulling loads of different tubes are different obviously. The pulling loads of the heat exchanger are assessed with ASME Code. The maximum pulling load is over the allowable force. FE method is a good technique to assess the distribution of the pulling loads and the location of the maximum pulling load. So it is useful and important to use FE method for forecasting the break and leak of the tubes.Copyright © 2005 by ASME

The safety analysis and test research are done to inspect the safety of 300MW control rod drive machine (CRDM) pressured shell structure in a systematic way. The test result agrees accords with FEA result. In actual operating mode (300 °C) inner-pressure fatigue simulative test, the axial and hoop pre-cracks are made, and the fatigue crack growth is observed. The load-bearing capability and deformation are tested in shell-burst test. Based on test research, this paper analyses theoretical load-bearing capability and safety margin in accordance with ASME CODE Sec. III design is calculated. Elastic-plastic fracture mechanics theory and GEGB.R6 method is used to analyze structure safety. The test results show pressure shell’s safety allowance is large enough.Copyright © 2005 by ASME