Modeling,analysis,and simulation of X-shape quasi-zero-stiffness-roller vibration isolators

Existing quasi-zero stiffness(QZS)isolators are reviewed.In terms of their advantages,a novel X-shape QZS isolator combined with the cam-roller-spring mechanism(CRSM)is proposed.Different from the existing X-shape isolators,oblique springs are used to enhance the negative stiffness of the system.Meanwhile,the CRSM is used to eliminate the gravity of the loading mass,while the X-shape structure leaves its static position.The existing QZS isolators are demonstrated and classified according to their nonlinearity mechanisms and classical shapes.It is shown that the oblique spring can realize negative stiffness based on the simplest mechanism.The X-shape has a strong capacity of loading mass,while the CRSM can achieve a designed restoring force at any position.The proposed isolator combines all these advantages together.Based on the harmonic balance method(HBM)and the simulation,the displacement transmissibilities of the proposed isolator,the X-shape isolators just with oblique springs,and the X-shape isolators in the traditional form are studied.The results show that the proposed isolator has the lowest beginning isolation frequency and the smallest maximum displacement transmissibility.However,it still has some disadvantages similar to the existing QZS isolators.This means that its parameters should be designed carefully so as to avoid becoming a bistable system,in which there are two potential wells in the potential energy curve and thus the isolation performance will be worsened.

Venous thromboembolism in children with acute lymphoblastic leukemia in China:a report from the Chinese Children’s Cancer Group-ALL-2015

Venous thromboembolism(VTE)is a complication in children with acute lymphoblastic leukemia(ALL).The Chinese Children’s Cancer Group-ALL-2015 protocol was carried out in China,and epidemiology,clinical characteristics,and risk factors associated with VTE were analyzed.We collected data on VTE in a multiinstitutional clinical study of 7640 patients with ALL diagnosed in 20 hospitals from January 2015 to December 2019.First,VTE occurred in 159(2.08%)patients,including 90(56.6%)during induction therapy and 108(67.92%)in the upper extremities.T-ALL had a 1.74-fold increased risk of VTE(95%CI 1.08–2.8,P=0.022).Septicemia,as an adverse event of ALL treatment,can significantly promote the occurrence of VTE(P<0.001).Catheter-related thrombosis(CRT)accounted for 75.47%(n=120);and,symptomatic VTE,58.49%(n=93),which was more common in patients aged 12–18 years(P=0.023),non-CRT patients(P<0.001),or patients with cerebral thrombosis(P<0.001).Of the patients with VTE treated with anticoagulation therapy(n=147),4.08%(n=6)had bleeding.The VTE recurrence rate was 5.03%(n=8).Patients with VTE treated by non-ultrasoundguided venous cannulation(P=0.02),with residual thrombus(P=0.006),or with short anticoagulation period(P=0.026)had high recurrence rates.Thus,preventing repeated venous puncture and appropriately prolonged anticoagulation time can reduce the risk of VTE recurrence.

Integrative analysis of transcriptomic and metabolomic profiles reveals new insights into the molecular foundation of fruit quality formation in Citrullus lanatus(Thunb.)Matsum.&Nakai

In this study,an integrated transcriptome and metabolome analysis was used to explore the molecular foundation of fruit quality in two parent lines of Citrullus lanatus with distinct flesh characteristics,including ‘14-1’(sweet,red,and soft)andW600'(bitter,light yellow,and firm),as well as the corresponding F,population(bitter,light yellow,and firm).Numerous differentially expressed genes(DEGs)were identified in the fruit samples:3766 DEGs for ‘14-1’vs.W600,2767 for ‘14-1’vs.F_(1),and 1178 for F_(1) vs.‘W600’at the transition stage;and 4221 for ‘14-1’vs.W6002447 for ‘14-1’vs.F,and 446 for F,vs.‘W600’at the maturity stage.Weighted gene co-expression network analysis(WGCNA)revealed that a gene module including 1111 DEGs was closely associated with flesh taste and color,and another gene module including 1575 DEGs contributed significantly to flesh texture.The metabolomic results showed that there were 447 differential metabolites(DMs)for ‘14-1’vs.‘W600’fruits,394 for ‘14-1’vs.F,and 298 for F,vs.‘W600’at the maturity stage.Combining WGNCA and metabolomic results,several DEGs and DMs were further identified as hub players in fruitqualityformation:6DEGs with 4DMs for flesh sweetness;6DEGs with 13DMs forbitterness;9DEGs with 10 DMs for flesh color;and 9 DEGs with 4 DMs for flesh texture.Altogether,these observations not only expand our knowledge of the molecular basis of fruit quality in watermelon,but also provide potential targets for future watermelon improvement.