基于拮抗机制的可变刚度流体驱动柔性致动器研究

柔性致动器具有柔顺性高、环境适应性强及人机交互性好等特点。针对传统柔性制动器刚度控制性能差的问题,基于柔性伸长肌和收缩肌的拮抗机制,提出一种新型可变刚度的流体驱动柔性致动器,该致动器能够实现伸长/缩短的复合动作,并通过协同调整伸长和收缩力实现刚度的控制;基于伸长及收缩织物的柔性形变机理,建立了柔性致动器的力学特性模型,并进行了仿真分析;开展了柔性致动器的力学特性试验,测试了致动器在不同充压及形变位移下的力学特性,并验证了柔性致动器的刚度调节特性。     

基于苦味受体表达的多组织细胞传感器及其应用

非口腔组织中的苦味受体(TAS2Rs)可能成为相关疾病治疗的新靶点。 该研究将表达有 TAS2Rs 的细胞作为敏感元 件,根据其生理特性与不同的传感器耦合,探究了味觉受体异位表达及其在个性化药物筛选中的应用,构建了针对不同疾病模 型的个性化药物筛选平台。 首先,基于细胞阻抗传感器以及内源性表达 TAS2R38 受体的结肠癌细胞,开发了异硫氰酸酯类物 质特异性药物筛选平台,求得苯硫脲的 EC50 为 157. 6 μM;其次,结合微电极阵列检测系统,探究了 TAS2Rs 激动剂地芬尼多 (5~ 160 μM)和水杨苷(0. 001~ 100 μM)对心肌细胞收缩的抑制作用;此外,基于 3D 呼吸道平滑肌细胞 (ASMCs) 阵列,结合凝 胶成像系统,探究了 TAS2Rs 激动剂桔皮素(20 μM)对呼吸道平滑肌细胞的舒张作用。     

A Maternal High Fat Diet Has Long‐Lasting Effects on Skeletal Muscle Lipid and PLIN Protein Content in Rat Offspring at Young Adulthood

A maternal high fat diet (HFD) can have adverse effects on skeletal muscle development. Skeletal muscle PLIN proteins (PLIN2, 3 and 5) are thought to play critical roles in lipid metabolism, however effects of HFD on PLIN and lipases (HSL, ATGL, CGI‐58) in mothers as well as their offspring have yet to be investigated. The primary objective of this study was to determine whether maternal HFD would influence skeletal muscle lipase and PLIN protein content in offspring at weaning (19d) and young adulthood (3mo). Female rats (28d old, n = 9/group) were fed control (CON, AIN93G, 7 % soybean oil) or HFD (AIN93G, 20 % lard) for 10 weeks prior to mating and throughout pregnancy and lactation. All offspring were weaned to CON [n = 18/group, 1 female and 1 male pup per litter were studied at weaning (19d) and 3mo of age]. There was no effect of sex for the main outcomes measured in plantaris, therefore male and female data was combined. Maternal HFD resulted in higher triacylglycerol content in pups at 3mo (p < 0.05), as well as in the dams (p = 0.015). Maternal HFD resulted in higher PLIN5 content in pups at weaning and 3mo (p = 0.05). PLIN2 and PLIN5 content decreased at 3mo versus weaning (p < 0.001). HFD dams had a higher PLIN3 content (p = 0.016). Diet had no effect on ATGL, CGI‐58, or HSL content. In conclusion, exposure to a maternal HFD resulted in higher skeletal muscle lipid and PLIN5 content in plantaris of offspring through to young adulthood.     

Ultraviolet B (UVB) Irradiation-Induced Apoptosis in Various Cell Lineages in Vitro

Ultraviolet B (UVB) radiation acts as a strong apoptotic trigger in many cell types, in tumor and normal cells. Several studies have demonstrated that UVB-induced cell death occurs through the generation of reactive oxygen species. The consequent oxidative stress includes the impairment of cellular antioxidants, the induction of DNA damage and the occurrence of apoptosis. In this review, we investigated UVB apoptotic action in various cell models by using ultrastructural, molecular and cytofluorimetric techniques. Myeloid leukemia HL-60, T-lymphoblastoid Molt-4 and myelomonocytic U937 human cells, generally affected by apoptotic stimuli, were studied. Human chondrocytes and C2C12 skeletal muscle cells, known to be more resistant to damage, were also considered. All of them, when exposed to UVB radiation, revealed a number of characteristic apoptotic markers. Membrane blebbing, cytoplasm shrinkage and chromatin condensation were detected by means of electron microscopy. DNA cleavage, investigated by using agarose gel electrophoresis and TUNEL reaction, was observed in suspended cells. Differently, in chondrocytes and in skeletal muscle cells, oligonucleosomic DNA fragmentation did not appear, even if a certain TUNEL positivity was detected. These findings demonstrate that UVB radiation appears to be an ideal tool to study the apoptotic behavior.     

Role of Akirin in Skeletal Myogenesis

Akirin is a recently discovered nuclear factor that plays an important role in innate immune responses. Beyond its role in innate immune responses, Akirin has recently been shown to play an important role in skeletal myogenesis. In this article, we will briefly review the structure and tissue distribution of Akirin and discuss recent advances in our understanding of its role and signal pathway in skeletal myogenesis.     

Distribution of trace metals in a ling (Genypterus blacodes) fish fillet

The distribution of trace metals in a ling (Genypterus blacodes) fish fillet was determined from ICP-MS measurements of digests prepared using nitric acid and hydrogen peroxide, followed by microwave digestion. Most trace elements were inhomogeneously distributed in the muscle tissue of the ling with a non-linear increase in concentration towards the tail end of the fillet. This distribution pattern may be connected to the size variation of the individual muscle cells or the change in the ratio of connective tissue to muscle tissue, suggesting that the observed inhomogeneity of muscle elemental distribution may be inherent to all fish species. The concentration of an element in a sample of fish muscle tissue thus depends on the physical location within the fish from which the sample was dissected. Significant differences in trace element concentrations were also detected between the red and white muscle fibres of ling, as well as between the belly flap and the rest of the musculature.     

Design and development of innovative textile pneumatic muscles

In recent years, the use of pneumatics in innovative actuation systems has led to the development, testing and first applications of nonconventional actuators such as pneumatic muscles. Like human muscles, pneumatic muscles can exert only traction forces, and offer a good power-to-weight ratio. The paper will present an investigation of new pneumatic muscles with a fabric structure. Lightweight, robust and efficient, these muscles can be used in a wide range of fields, from biomedical to industrial applications.     

6-Iso-chlortetracycline or keto form of chlortetracycline? Need for clarification for relevant monitoring of chlortetracycline residues in food

Chlortetracycline (CTC) is a broad-spectrum antibiotic used in veterinary medicine for pulmonary or digestive infections and having a regulatory maximum residue limit (MRL) necessitating an official analytical control method. The purpose of this study was to clarify the identification of different forms of CTC observed in standard solution, in spiked muscle samples and in naturally incurred muscle samples of pigs analysed by LC-MS/MS and to demonstrate the in vivo formation of 6-iso-chlortetracycline and 4-epi-6-iso-CTC as a metabolite of CTC and 4-epi-CTC in muscle. The six following forms were identified, all being isobaric with a protonated molecule at m/z 479 (precursor ion): the keto-enol forms of CTC and the keto-enol forms of 4-epi-chlortetracycline (4-epi-CTC), 6-iso-chlortetracycline (6-iso-CTC) and 4-epi-6-iso-chlortetracycline (4-epi-6-iso-CTC). The 6-iso-CTC and 4-epi-6-iso-CTC were observed only in incurred pig samples so were identified for the first time as metabolites of CTC and 4-epi-CTC. Identification of the different forms was obtained by comparing incurred muscle samples with standard solutions and with spiked samples. Then the differences between the features of the chromatograms obtained by LC-TQ-MS and the fragmentation study of the different forms of CTC obtained by LC-Q-TOF-MS helped us to support this identification. The extraction steps and the LC-MS/MS conditions developed to analyse muscle tissue samples are described. This clarification concerning the rigorous identification of chromatographic peaks allowed us to evaluate the relevance of our monitoring method with regard to the regulations in place in the European Union and could be of help to laboratories involved in official control of antibiotic residues in food of animal origin. Additional results are also presented highlighting the transformation of the CTC when prepared in a mixture with other antibiotics.     

Effect of isoelectric solubilization/precipitation and titanium dioxide on whitening and texture of proteins recovered from dark chicken-meat processing by-products

Processing of chicken generates by-products containing muscle proteins attached to bones and skin that, if recovered, could be a functional ingredient in restructured food products. However, color of restructured products made of proteins recovered from chicken processing by-products is poor. The by-products contain bones, skin, fat, etc. that affect color of restructured products. Therefore, color properties need to be improved. The objectives of this study were to determine effects of isoelectric solubilization/precipitation (ISP) and TiO₂ on instrumental color and texture properties of heat-set gels made of proteins recovered from dark chicken-meat processing by-products as compared to gels made of chicken breast meat. Skin-on bone-in chicken drumsticks were used as a model dark chicken-meat processing by-products. TiO₂ at 0-1 g/100 g and canola oil at 10 g/100 g were added to the ISP-recovered proteins followed by cooking. Due to higher (P < 0.05) yellowness (b∗) and lower (P < 0.05) lightness (L∗), the whiteness of drumstick gels without TiO₂ was lower (P < 0.05) than breast gels. TiO₂ at 1 g/100 g with canola oil resulted in slightly better (P < 0.05) whiteness of drumstick gels than breast gels. TiO₂ did not deteriorate gel texture, which was generally comparable to breast gels. This research indicates that ISP allows recovery of proteins from skin-on bone-in dark chicken-meat processing by-products without removal of bones, skin, and fat prior to processing. Addition of TiO₂ to proteins recovered from these by-products allows development of heat-set gels with color and texture comparable to chicken breast gels. Although this study shows the potential for a novel, marketable food product, sensory tests are recommended.