Outlook on ecologically improved composites for aviation interior and secondary structures

Today, mainly man-made materials such as carbon and glass fibres are used to produce composite parts in aviation. Renewable materials such as natural fibres or bio-sourced resin systems have not found their way into aviation, yet. The project ECO-COMPASS aims to evaluate the potential applications of ecologically improved composite materials in the aviation sector in an international collaboration of Chinese and European partners. Natural fibres such as flax and ramie will be used for different types of reinforcements and sandwich cores. Furthermore, the bio-based epoxy resins to substitute bisphenol-A based epoxy resins in secondary structures are under investigation. Adapted material protection technologies to reduce environmental influence and to improve fire resistance are needed to fulfil the demanding safety requirements in aviation. Modelling and simulation of chosen eco-composites aims for an optimized use of materials while a life cycle assessment aims to prove the ecological advantages compared to synthetic state-of-the-art materials. In this paper, the status of selected ecologically improved materials will be presented with an outlook for potential application in interior and secondary structures

REPORTAJE CARMELO ARTILES BOLAÑOS. INFECAR [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Revisiting the flexion-valgus type unicondylar posterolateral tibial plateau depression fracture pattern: classification and treatment

Abstract Objective This study aimed to reclassify posterolateral tibial plateau fractures caused by a flexion-valgus force and describe this fracture pattern to provide a relatively programmed surgical treatment based on morphological characteristics that may improve reduction and stabilization. Methods We retrospectively reviewed the fracture pattern and injury mechanism of patients with posterolateral tibial plateau fractures who underwent surgery at the First Affiliated Hospital of Nanjing Medical University between January 2014 and April 2020. The cohort was divided into three types. Type I was a depression fracture of the posterolateral platform with an intact posterolateral cortex. Type II was a depression fracture of the posterolateral platform with a disrupted posterolateral cortex. Type III was a depression fracture of the posterolateral platform in combination with anterior cruciate ligament (ACL) rupture or tibial insertion avulsion fracture of the ACL. The lateral window of the modified Frosch approach with an L-type locking plate was used for patients with type I and type III fractures. For patients with type II fractures, both lateral and posterolateral windows of the modified Frosch approach were used for surgery, and a T-plate on the posterior side with an L-plate on the lateral side were used for fixation. The Rasmussen radiology scoring was used to evaluate the quality of surgical reduction and the Rasmussen functional scoring evaluation standard was used to evaluate knee joint function. Results A total of 69 tibial plateau fractures (36 male, 33 female) involving the posterolateral platform were discovered and included in this study. All patients suffered flexion-valgus force at the moment of the accident. There were 32 cases of Type I fracture, 28 cases of Type II fracture, and 9 cases of Type III fracture. The patients were followed up for 12–30 (mean 20.8 ± 9.4) months. The postoperative Rasmussen radiological scores for the three types of fractures were 15–17 (mean 16.31 ± 0.78), 14–17 (mean 15.93 ± 0.94), and 14–17 (mean 16.22 ± 0.97), respectively. The postoperative Rasmussen functional scores for the three types of fractions were 27–30 (mean 27.97 ± 0.90), 27–29 (mean 27.36 ± 0.56), and 27–29 (mean 27.56 ± 0.73), respectively. Conclusion Flexion-valgus posterolateral tibial plateau fractures were divided into three types based on the integrity of the posterolateral wall and ACL injuries. We hope the classification can play a certain reference role in recognizing and treating flexion-valgus-type posterolateral tibial plateau fractures

Static mechanical stress induces apoptosis in rat endplate chondrocytes through MAPK and mitochondria-dependent caspase activation signaling pathways.

Mechanical stress has detrimental effects on cartilaginous endplate chondrocytes due to apoptosis in vivo and in vitro. In this study, we investigated the possible apoptosis signaling pathways induced by mechanical stress in cultured rat cervical endplate chondrocytes. Static mechanical load significantly reduced cell viability in a time- and load-dependent manner, as demonstrated by the Cell Counting Kit-8 (CCK-8) assay. Chondrocyte apoptosis induced by mechanical stress was confirmed by annexin V/propidium iodide (PI) staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Western blot analysis revealed that static load-induced chondrocyte apoptosis was accompanied by increased phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (MAPK). The loss of mitochondrial membrane potential (ΔΨm), increased Cytochrome c release, and activated Caspase-9 and Caspase-3, indicating that the mitochondrial pathway is involved in mechanical stress-induced chondrocyte apoptosis. Treatment with inhibitors of JNK (SP600125), p38 MAPK (SB203580), and ERK (PD98059) prior to mechanical stimulation reversed both the static load-induced chondrocyte apoptosis and the activation of JNK, p38 MAPK, and ERK. Taken together, the data presented in this study demonstrate that mechanical stress induces apoptosis in rat cervical endplate chondrocytes through the MAPK-mediated mitochondrial apoptotic pathway

Prenatal thallium exposure and poor growth in early childhood: A prospective birth cohort study

Background: Thallium (Tl) exposure remains a public health problem with potential impacts on humans. Studies have suggested that prenatal exposure to thallium may be associated with fetal growth, but no studies are known have explored its association with early childhood anthropometry. Objective: To investigate the effects of prenatal Tl exposures on early child growth and development aged 0–2 years in a prospective birth cohort study. Methods: 3080 pregnant women and their children participated in the study, which were recruited from a birth cohort in China. Serum samples collected in the first and second trimester of pregnant subjects and umbilical cord blood of infants were analyzed for Tl exposure assessment. Infant length or standing height and weight were obtained from medical records and 2 years planned visits. We used length/height and weight to calculate z-scores for weight-for-age (WAZ), height-for-age (HAZ), weight-for-height (WHZ), and body mass index-for-age (zBMI) based on World Health Organization standards. Linear mixed model was used to investigate the association between serum concentrations of Tl and the children's anthropometric characteristics (WAZ, HAZ, WHZ, and zBMI), and stratification analysis by sex was also examined. Results: The median (P25-P75) of Tl levels in the first trimester, second trimester and umbilical cord serum were 61.7 (50.7–77.0), 60.1 (50.9–74.8) and 38.4 (33.6–43.9) ng/L, respectively. Paired Mann-Whitney tests found Tl concentrations in umbilical cord serum were significantly less than that in maternal serum during the first and second trimesters (all p < 0.01). Using adjusted linear mixed model, no significant relationships were observed between maternal Tl exposure and child growth parameters. However, the umbilical cord serum Tl levels may contributed to decreased WAZ (β = −0.382, 95% confidence interval (CI): −0.670, −0.095) and HAZ (β = −0.427, 95% CI: −0.702, −0.152). When stratified by sex, the umbilical cord serum Tl levels were negatively related to WAZ (β = −0.450, 95% CI: −0.853, −0.048) and HAZ (β = −0.775, 95% CI: −1.160, −0.391) for girls. Among boys, overall Tl exposures were not significantly associated with early children anthropometric outcomes. Conclusions: In the present study, our results suggested that prenatal Tl exposures may have a sex specific effect on child anthropometric measurements in the first 2 years of life. Umbilical cord serum Tl levels tended to be reduced child's stature and weight in young girls.</p

Effect of mechanical stress on the activation of caspases in endplate chondrocytes.

<p>(A) Chondrocytes were pre-treated with or without 20 µM Ac-DEVD-CHO for 1 h and then loaded under 0.5 MPa for 24 h. The expression levels of cleaved Caspase-9 and cleaved Caspase-3 were examined by western blotting. (B) Quantitative analysis of cleaved Caspase-9 and cleaved Caspse-3. The results are expressed as the mean ± SD of three separate experiments. *p<0.05; ***p<0.001 versus control cells, ^###p<0.001 versus loaded cells.</p

Static compression-induced mitochondrial dysfunction in endplate chondrocytes.

<p>Cells were exposed to 0.5 MPa in the presence or absence of specific inhibitors for 24 h, after which the mitochondrial membrane potential was determined by staining with the mitochondrial dye JC-1. Red fluorescence represents JC-1 aggregates formed in healthy cells with high mitochondrial membrane potential, whereas green fluorescence highlights JC-1 monomers in cells with low ΔΨm. Scale bar = 100 µm.</p

Effect of mechanical stress-induced cell apoptosis in endplate chondrocytes.

<p>Chondrocytes were pretreated with or without specific inhibitors for 1 h and then incubated under 0.5 MPa for a further 24 h. (A) Apoptosis was assayed by flow cytometry using annexin-V/PI double staining. (B) The percentage of apoptotic chondrocytes loaded for 24 h. Data are presented as the mean ± SD of three independent experiments. ***p<0.001 versus unloaded cells; ^###p<0.001 versus loaded cells.</p

Static mechanical load-induced cell death in endplate chondrocytes.

<p>Chondrocytes were exposed to various static loads for 1, 6, 12, 24, 36, and 48 h. Cell viability was detected by using the CCK-8 assay. Each value represents the mean ± SD, n = 3. *p<0.05; **p<0.01; ***p<0.001 compared with the control group.</p

Effect of mechanical stress on the expression of apoptosis-related proteins.

<p>Chondrocytes were loaded under 0.5 MPa for 24 h in the presence or absence of specific MAPK inhibitors, and the protein levels of Bax, Bcl-2, and Cytochrome <i>c</i> were assessed by western blot analysis. Expression of β-actin was used as an internal control. Data are presented as the mean ± SD of three independent experiments. *p<0.05; **p<0.01 versus unloaded cells, ^#p<0.05;^##p<0.01; ^###p<0.001 versus loaded cells.</p