Abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type

Objective:To explore the abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type.Methods:The 30 healthy individuals included in the method were from the Physical Examination Center of Anhui Provincial Hospital of Traditional Chinese Medicine,and the 60 rheumatoid arthritis patients included were from the First Affiliated Hospital of Anhui University of Traditional Chinese Medicine.The disease activity score of patients with rheumatoid arthritis was evaluated using VAS score and DAS28 score,joint symptoms and spleen deficiency syndrome score were evaluated using graded quantification method,immune inflammation indicators were detected using relevant instruments,inflammatory cytokines were detected using ELISA method,macrophage markers were detected using FCM method,and pathway gene expression was detected using RT-qPCR;Evaluate the predictive effect of circ-CBLB and miR-486-5p on disease activity in rheumatoid arthritis using ROC curves.Results:(1)miR-486-5p,CD14^(+)CD86^(+),ESR,CRP,RF,Anti CCP Ab,IL-6,TNF in patients with rheumatoid arthritis-αThe levels of circ-CBLB,CD14^(+)CD163^(+),IL-4,and IL-10 were significantly higher than those of healthy individuals;(2)The expression level of circ-CBLB in patients with rheumatoid arthritis is positively correlated with CD14^(+)CD163^(+),and negatively correlated with miR-486-5p and CD14^(+)CD86^(+);The expression level of miR-486-5p is negatively correlated with CD14^(+)CD163^(+)and positively correlated with CD14^(+)CD86^(+);There is a negative correlation between CD14^(+)CD86^(+)and CD14^(+)CD163^(+);ESR is negatively correlated with circ-CBLB,and positively correlated with miR-486-5p,CD14^(+)CD86^(+),CRP;CRP is negatively correlated with circ-CBLB,CD14^(+)CD163^(+),and positively correlated with CD14^(+)CD86^(+),ESR;(3)The expression level of circ-CBLB in patients with rheumatoid arthritis is negatively correlated with joint tenderness,morning stiffness,lack of qi and lazy speech,and postprandial abdominal distension score;The expression level of miR-486-5p is positively correlated with the scores of joint tenderness and decreased appetite.(4)The ROC curve shows that in terms of circ-CBLB,ESR,CRP,VAS,and DAS28 AUC are 0.662(P=0.032),0.658(P=0.035),0.516(P=0.830),and 0.791(P=0.000),respectively.In terms of miR-486-5p,ESR,CRP,VAS,and DAS28 AUC were 0.566(P=0.385),0.511(P=0.883),0.592(P=0.223),and 0.727(P=0.003),respectively.Conclusion:The abnormal expression of circ CBLB and miR-486-5p in peripheral blood mononuclear cell of patients with rheumatoid arthritis of spleen deficiency and dampness excess type is related to inflammatory polarization markers,immune inflammation,disease activity,joint symptoms and spleen deficiency syndrome of rheumatoid arthritis,and the low expression of circ CBLB and high expression of miR-486-5p have certain predictive value for disease activity of rheumatoid arthritis.

Observation on Therapeutic Effects of Electroacupuncture on Polycystic Ovary Syndrome of Kidney Deficiency and Phlegm Dampness Type and Oxidative Stress Level

Objective:To observe the clinical effect of electroacupuncture on improving polycystic ovary syndrome(PCOS)of kidney deficiency and phlegm dampness type and serum oxidative stress level.Methods:There were 68 patients with polycystic ovary syndrome were randomly divided into observation group(34 cases)and the control group(34 cases),The observation group was treated by electroacupuncture,while the control group was treated by placebo electroacupuncture.Combined with the evaluation of menstrual cycle,menstrual color,quality,quantity and TCM symptom integral index,the difference of curative effect between the two groups was observed,and the levels of peripheral blood,sex hormones,insulin resistance and oxidative stress were detected before and after treatment for 3 months.Results:The total effective rate in the observation group was better than that in the control group(P<0.01);After intervention,serum LH,FSH,E_(2) and LH/FSH in the observation group were significantly different from those before intervention.The D values of serum LH,FSH,LH/FSH and E_(2) before and after intervention were significantly different between the two groups(P<0.01);Comparing the level of androgen,the serum A4 and T in the observation group were significantly different from those before intervention(P<0.01);After intervention,there was a significant difference in serum A4 and T between the two groups(P<0.01),and there was a significant difference in D value between the two groups before and after intervention;There was a difference in insulin resistance in the observation group before and after intervention(P<0.05),and there was a significant difference in D value between the two groups before and after intervention(P<0.01);After the intervention,the serum SOD,MDA,ROS in the observation group were significantly different from those before the intervention;After intervention,the results of serum SOD and ROS in the observation group were significantly different from those in the control group;There was no significant difference in serum MDA results.There were significant differences in SOD,MDA,ROS between the two groups before and after intervention.Conclusion:Electroacupuncture can improve oxidative stress injury,insulin resistance and hyperandrogenism in PCOS patients.

Exploration and Study of Jianpi Qushi Powder Combined with Standard Anti HP Quadruple Therapy in the Treatment of HP Infectious Gastritis of Spleen Deficiency and Dampness Stagnation Type

Objective: To explore the therapeutic effect of traditional Chinese medicine Jianpi Qushi powder combined with standard anti-HP quadruple therapy in the treatment of HP infectious gastritis with spleen deficiency and dampness stagnation. Methods: From January 2020 to December 2021, 223 patients with laboratory-confirmed HP infection who were admitted to the Outpatient and Inpatient Department of Internal Medicine in our hospital were selected as the research objects and randomly divided into two groups. 101 patients in the control group were given standard anti HP quadruple therapy;122 cases in the treatment group were given traditional Chinese medicine Jianpi Qushi powder combined with standard anti HP quadruple therapy. The two groups were rechecked carbon breath test after the designed course of treatment, and the curative effects of the two groups were compared. Results: 113 cases in the treatment group were cured by traditional Chinese medicine Jianpi Qushi powder combined with standard anti HP quadruple therapy, and the cure rate was 92.62%. 84 cases in the control group were cured by standard anti HP quadruple therapy, and the cure rate was 83.17%, χ2 = 4.7955, P = 0.0285, the difference was statistically significant (P < 0.05). Conclusion: Traditional Chinese medicine Jianpi Qushi powder combined with standard anti HP quadruple therapy in the treatment of HP infectious gastritis with spleen deficiency and dampness stagnation is one of the best treatment schemes for HP infection. The results of this study achieve the best clinical treatment effect, and provide a more valuable and reliable method for the treatment of gastropathy in clinical internal medicine, which is worthy of popularization and application.

Research Progress of Jianpi Qushi Powder Combined with Standard Anti Hp Quadruple Therapy in the Treatment of Hp Infectious Gastritis with Spleen Deficiency and Dampness Stagnation

Stomach Helicobacter pylori infection is one of the common gastric diseases. Helicobacter pylori infectious gastritis of spleen deficiency and dampness stagnation is a relatively intractable chronic disease. In recent years, traditional Chinese medicine methods have emerged one after another in the treatment of gastric Helicobacter pylori infection. By collecting references, the author reviewed the clinical characteristics of gastric Helicobacter pylori infection and the new progress of traditional Chinese medicine treatment.

Pullback attractor of 2D nonautonomous g-Navier-Stokes equations with linear dampness

The pullback attractors for the 2D nonautonomous g-Navier-Stokes equations with linear dampness axe investigated on some unbounded domains. The existence of the pullback attractors is proved by verifying the existence of pullback D-absorbing sets with cocycle and obtaining the pullback ：D-asymptotic compactness. Furthermore, the estimation of the fractal dimensions for the 2D g-Navier-Stokes equations is given.

Analysis of treatment strategies of traditional Chinese medicine for COVID-19 in tropical regions based on the pathogens of dampness and heat

Objective:To summarize the treatment strategies of Traditional Chinese Medicine(TCM)for COVID-19 in tropical regions based on the pathogens of dampness and heat.Methods:For heat pathogen,analyzing heat in the superficies,lung and Yang Ming based on the different locations.Based on the progress of the disease,analyzing the stage of toxin and Qi deficiency induced by heat.For dampness pathogen,analyzing endogenous and external dampness based on the different locations.Analyzing dampness pathogen's special disease location—Moyuan and special symptom of dry cough with less sputum caused by sticky and stagnant characteristic of dampness.Results:The treatment strategies for heat and dampness pathogen were summarized.Conclusion:In the tropics,the pathogens of dampness and heat occur frequently and clinical treatments need to be dialectical.

Clinical effect of enriching qi, activating blood circulation, clearing away dampness and heat combined with western medicine in the treatment of idiopathic membranous nephropathy: A meta-analysis

Objective:To systemically review the efficacy and safety about the method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine in the therapy of patients with idiopathy membranous nephropathy(IMN).Methods:We collected the randomized controlled trials(RCTs)of enriching qi,activating blood circulation,clearing away dampness and heat for the treatment of IMN from Pub Med,The Cochrane Library,Medline,China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),Wanfang Data and Wiper Databases.Bias of risk of retrieval literature was evaluated according to Cochrane Collaboration standard,and Review Manager 5.3 software was used for statistical analysis.Results:Fourteen trials(836 participants)were included in the meta-analysis.This kind of traditional Chinese method combined with western medicine in the treatment of IMN exerted statistical differences in reducing 24-hour urinary protein[WMD=-0.97,95%CI(-1.30,-0.65),Z=5.86(P<0.00001)]and elevating serum albumin[WMD=3.83,95%CI(2.10,5.57),Z=4.33,P<0.0001],lowering serum cholesterol[WMD=-0.82,95%CI(-1.08,-0.56),Z=6.18,P<0.00001],triglycerides[WMD=-0.39,95%CI(-0.67,-0.11),Z=2.77,P=0.006]and reducing the risk of adverse events[OR=0.29,95%CI[0.16,0.50],Z=4.35,P<0.0001]in the patients with IMN as compared with controls.However,there was no statistically significant difference between the method and controls when combining all trials in serum creatinine[WMD=-5.52,95%CI(-18.06,7.03),Z=0.86,P=0.39],when combining all trials in urea nitrogen[WMD=-0.90,95%CI(-2.22,0.41),Z=1.35,P=0.18].Conclusion:The method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine exerts certain advantages and better safety in treating patients with IMN.However,for the inferiority of the included studies,the conclusion still needs high-quality and large-sample prospective randomized controlled trials to verify.

Indoor Exposure to Mould and Dampness in Infancy and Its Association to Persistent Atopic Dermatitis in School Age: Results from the Greek ISAAC II Study

Introduction: The presence of mould as a source of perennial allergens and bacteria products has been related to the appearance of respiratory symptoms in several studies. Yet, its role in eczema has not been elucidated. The aim of this study was to investigate the association between exposure to indoor visible molds/dampness and the manifestation of eczema in children. Methods: The study is part of the Greek contribution to ISAAC IΙ that includes 2023 students of randomly selected public primary schools in Athens and Thessaloniki, aged 9 - 10 years old. The children represented a general population sample and were evaluated according to ISAAC II questionnaire, validated for Greek language. Additionally, skin prick tests to aero-allergens were performed and children were examined for active skin lesions. Results: 13% had suffered from eczema in the past, 9% had current and 2% had atopic eczema (positive at least one skin prick test). Out of the children examined, half reported that eczema first appeared after the age of five years old whereas 70% mentioned persistence of eczema. Dampness was reported in 10.8% and visible mould in 6.4% of all cases during infancy, while continued exposure until the age of 10 years old was reported in 38% and 33% out of them respectively. 10.8% of the sensitized children were positive to house dust mites and Alternaria, however, sensitization was not related to indoor exposure. In logistic regression analysis evaluating 20 environmental risk factors, a significant association was noted between the presence of indoor visible mold and dampness in infancy, and the presence of current eczema OR 1, 89 (95%CI 1.18 - 3.03). This association remained significant irrespective of the family history of eczema and sensitization. Conclusions: Frequently eczema first appears at early school age. The presence of visible mold and dampness at home during infancy appears to be an initial enhancing risk factor for the development but also for the persistence of the disease throughout school age.

Clinical Observation of Zhuang Medicine Yangxue Xiaozheng Decoction in Treating the Combined Endometriosis of Dampness and Blood Stasis in Guangxi

Objective:To explore the clinical effects of Zhuang Medicine Yangxue Xiaozheng Decoction in treating the combined Ems of dampness and blood stasis in Guangxi;Methods:100 patients with endometriosis treated in Lili Clinic of Famous Doctor,Guangxi International Zhuang Medicine Hospital from Mach 2016 to May 2017 were chosen as the research object.According to the random grouping method,patients were randomly divided into the treatment group(The Zhuang Medicine Yangxue Xiaozheng Decoction(ZYF)Group)and the control group(Chinese patent medicine SanJieZhenTongJiaoNang(SJZT)group with 50 cases in each group.After treatment,the TCM syndrome score,changes in pelvic mass size,hepatocyte growth factor(HGP)levels,and clinical effects before and after treatment were evaluated.Results:After two courses of treatment,the total effective rate of patients in the ZYF group was 88%,which were significantly better than 70%of the SJZT group.The difference was statistically significant(P<0.05).Conclusion:With a significant effect on patients with the combined Ems of dampness and blood stasis in Guangxi,Zhuang Medicine Yangxue Xiaozheng Decoction can improve the uterine cavity mass and reduce serum HGP level.

Reporting Bias of Dampness Problems and Smoking—A Result of Study Design

Using questionnaire is a common, efficient and cheap way to collect data in population-based epidemiological studies. However, there is a general trend of declining response rates leading to a higher risk for bias affecting the validity of results. Use of anonymous questionnaires and/or other ways of distributions, e.g. via schools instead of postal, may increase response rates, but can also lead to other types of systematic errors. This study indicates that results from cross-sectional questionnaire studies differ depending on distribution method and whether the survey is anonymous or not. Also the official purpose of the survey may affect the outcome. When studying well-known risk-factors and health effects, potential methodological problems like reporting bias must be considered in cross sectional studies.

Effects of Cangfudaotan Tang on Expression of Organic Anion Transporting Polypeptide (oatp2b1) in Liver and Kidney Tissues of Rats with Phlegm Dampness Type Polycystic Ovary Syndrome (PCOS)

Objective: To explore the effect of Cangfudaotan Tang on phlegm dampness type of PCOS and the role of oatp2b1 in transportation and transformation of phlegm dampness. Methods: 36 SD female rats were randomly divided into three groups: blank control group, model group and Cangfudaotan Tang group, 12 cases in each one. After PCOS rat models were made, rats of Cangfudaotan Tang group were treated with Cangfudaotan Tang (1.42 g/kg/d) by intragastric administration for 14 days;blank control and model group were given with isodose saline. The expression of oatp2b1 mRNA/Protein in liver and kidney tissues was measured and the level of testosterone (T), follicle stimulating hormone(FSH), estradiol (E2), luteinizing hormone(LH), Serum total cholesterol (TG), Triacylglycerols (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were detected at the same time. Results: Compared with blank control group, the expression of oatp2b1 mRNA and the level of TC, TG, LDL, LH, FSH, T in model group were significantly increased (P < 0. 05), while the level of HDL was significantly decreased (P < 0. 05);compared with model group, the expression of oatp2b1 mRNA and the level of TC, TG, LDL in Cangfudaotan Tang group were significantly lowered (P < 0.05);the level of HDL was significantly higher;the oatp2b1 protein in kidney and liver tissues had different degrees of expression, while there was no statistical significance among the three groups. Conclusions: Oatp2b1 might be one of the material bases participating in transportation and transformation of phlegmy dampness. The mechanism of Cangfudaotan Tang treating phlegm dampness type of PCOS may be achieved by regulating the expression of oatp2b1.

Screening the effective components in treating dampness stagnancy due to spleen deficiency syndrome and elucidating the potential mechanism of Poria water extract

Poria is an important medicine for inducing diuresis to drain dampness from the middle energizer.However,the specific effective components and the potential mechanism of Poria remain largely unknown.To identify the effective components and the mechanism of Poria water extract(PWE)to treat dampness stagnancy due to spleen deficiency syndrome(DSSD),a rat model of DSSD was established through weight-loaded forced swimming,intragastric ice-water stimulation,humid living environment,and alternate-day fasting for 21 days.After 14 days of treatment with PWE,the results indicated that PWE increased fecal moisture percentage,urine output,D-xylose level and weight;amylase,albumin,and total protein levels;and the swimming time of rats with DSSD to different extents.Eleven highly related components were screened out using the spectrum-effect relationship and LC-MS.Mechanistic studies revealed that PWE significantly increased the expression of serum motilin(MTL),gastrin(GAS),ADCY5/6,p-PKAα/β/γcat,and phosphorylated cAMP-response element binding protein in the stomach,and AQP3 expression in the colon.Moreover,it decreased the levels of serum ADH,the expression of AQP3 and AQP4 in the stomach,AQP1 and AQP3 in the duodenum,and AQP4 in the colon.PWE induced diuresis to drain dampness in rats with DSSD.Eleven main effective components were identified in PWE.They exerted therapeutic effect by regulating the AC-cAMP-AQP signaling pathway in the stomach,MTL and GAS levels in the serum,AQP1 and AQP3 expression in the duodenum,and AQP3 and AQP4 expression in the colon.

Modulating effects of Astragalus polysaccharide on immune disorders via gut microbiota and the TLR4/NF-κB pathway in rats with syndrome of dampness stagnancy due to spleen deficiency

The syndrome of dampness stagnancy due to spleen deficiency(DSSD)is relatively common globally.Although the pathogenesis of DSSD remains unclear,evidence has suggested that the gut microbiota might play a significant role.Radix Astragali,used as both medicine and food,exerts the effects of tonifying spleen and qi.Astragalus polysaccharide(APS)comprises a macromolecule substance extracted from the dried root of Radix Astragali,which has many pharmacological functions.However,whether APS mitigates the immune disorders underlying the DSSD syndrome via regulating gut microbiota and the relevant mechanism remains unknown.Here,we used DSSD rats induced by high-fat and low-protein(HFLP)diet plus exhaustive swimming,and found that APS of moderate molecular weight increased the body weight gain and immune organ indexes,decreased the levels of interleukin-1β(IL-1β),IL-6,and endotoxin,and suppressed the Toll-like receptor 4/nuclear factor-κB(TLR4/NF-κB)pathway.Moreover,a total of 27 critical genera were significantly enriched according to the linear discriminant analysis effect size(LEfSe).APS increased the diversity of the gut microbiota and changed its composition,such as reducing the relative abundance of Pseudoflavonifractor and Paraprevotella,and increasing that of Parasutterella,Parabacteroides,Clostridium XIVb,Oscillibacter,Butyricicoccus,and Dorea.APS also elevated the contents of short-chain fatty acids(SCFAs).Furthermore,the correlation analysis indicated that 12 critical bacteria were related to the body weight gain and immune organ indexes.In general,our study demonstrated that APS ameliorated the immune disorders in DSSD rats via modulating their gut microbiota,especially for some bacteria involving immune and inflammatory response and SCFA production,as well as the TLR4/NF-κB pathway.This study provides an insight into the function of APS as a unique potential prebiotic through exerting systemic activities in treating DSSD.

诱导抑郁症患者小胶质细胞炎性反应的机制

小胶质细胞炎性反应是抑郁症患者及相关动物模型中广泛观察到的病理现象,与抑郁症密切相关。抑郁症中诱导小胶质细胞炎性反应的机制包括下丘脑-垂体-肾上腺(HPA)轴激活后糖皮质激素水平变化直接或间接的调控作用、肠道微生物代谢物通过脑肠轴中免疫与神经途径的作用以及损伤相关分子模式(DAMPs)对小胶质细胞的直接激活作用等。

Microstructure and damping properties of LPSO phase dominant Mg-Ni-Y and Mg-Zn-Ni-Y alloys

This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.

Efficacy of Modified Qufeng Runmian Powder(加减祛风润面散)on Acne Vulgaris with Syndromes of Dampness and Blood Stasis:A Multicenter,Randomized,Double-Blind,Placebo-Controlled Clinical Trial

Objective:To evaluate the efficacy and safety of a Chinese medicine(CM)Modified Qufeng Runmian Powder(加减祛风润面散,MQFRMP)for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis.Methods:In this multicenter,randomized,double-blind,placebo-controlled clinical trial,220 acne vulgaris patients with CM syndrome of dampness and blood stasis were included and randomly assigned using a central area group random design to receive either MQFRMP or the placebo,with 110 cases in each group.MQFRMP or a placebo at 145 g/bag were administered once daily for 4 weeks,respectively.The primary index of efficacy was the effective rate according to the acne severity score(ASS).The secondary indices of efficacy included the changes in the dermatology life quality index(DLQI)score,VISIA scores(spots,pores,brown spots,porphyrins and red areas)and skin assessment(skin p H,sebum amount and hydration)according to a SOFT skin multianalyzer.Results:(1)Follow-up:a total of 204 patients completed the follow-up,with 103 in the treatment group and 101 in the control group.(2)Effective rate:the total effective rate of the treatment group was significantly higher than the control group[83.5%(86/103)vs.31.7%(32/101),P<0.01)]with 95%confidence interval of 39.3%–66.4%.(3)DLQI:DLQI scores were significantly decreased the treatment and control groups(both P<0.01),but the treatment group was more obvious than the placebo group(P<0.01).(4)VISIA scores:the scores of spots,brown spots and red areas in the treatment group decreased compared with baseline(P<0.05).In the control group,the scores of brown spots and pores decreased compared with baseline(P<0.05).The improvement was more obvious in the treatment group than in the control group for all items(P<0.05).(5)Skin assessment:the p H and sebum score in the both groups decreased drastically compared with the baseline(all P<0.01),however,the improvement was more obvious in the treatment group than in the control group(P<0.01).The hydration amount in the two groups showed no statistically significant difference compared with the baseline(both P>0.05).(6)Safety:two cases of mild drug allergy were observed in the treatment group.Conclusion:MQFRMP was effective and safe for the treatment of acne vulgaris with syndromes of dampness and blood stasis.(No.ChiCTR1900020479).

Transformation between polar and rectangular coordinates of stiffness and dampness parameters in hydrodynamic journal bearings

The stiffness and dampness parameters of journal bearings are required in rectangular coordinates for analyzing the stability boundary and threshold speed of oil film bearings.On solving the Reynolds equation,the oil film force is always obtained in polar coordinates;thus,the stiffness and dampness parameters can be easily obtained in polar coordinates.Therefore,the transformation between the polar and rectangular coordinates of journal bearing stiffness and dampness parameters is discussed in this study.

Aseismic performances of constrained damping lining structures made of rubber-sand-concrete

Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.

Equivalent linear model for seismic damage evaluation of single-degree-of-freedom systems representing reinforced concrete structures considering cyclic degradation behavior

In this study,a novel equivalent damping ratio model that is suitable for reinforced concrete(RC)structures considering cyclic degradation behavior is developed,and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is presented.To this end,Ibarra’s peak-oriented model,which incorporates an energy-based degradation rule,is selected for representing hysteretic behavior of RC structure,and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method,in which the effect of cyclic degradation is considered.Moreover,the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage evaluation.Due to the simplicity of the equivalent linearization method,the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC structures.The verification demonstrates the validity of the proposed method.

Mechanical and damping performances of TPMS lattice metamaterials fabricated by laser powder bed fusion

Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ships.However,its vibration and noise reduction,and damping properties have not been fully studied.Therefore,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static compression.The modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal tests.For the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,respectively.The results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.