Musculoskeletal computational analysis on muscle mechanical characteristics of drivers' lumbar vertebras and legs in different sitting postures.

Using computer-aided engineering (CAE) in the concept design stage of automobiles has become a hotspot in human factor engineering research. Based on human musculoskeletal biomechanical computational software, a seated human-body musculoskeletal model was built to describe the natural sitting posture of a driver. The interaction between the driver and car in various combinations of seat-pan/back-rest inclination angles was analyzed using an inverse-dynamics approach. In order to find out the "most comfortable" driving posture of the seat-pan/back-rest, the effect of seat-pan/back-rest inclination angles on the muscle activity degree, and the intradiscal L4-L5 compression force were investigated. The results showed that a much larger back-rest inclination angle, approximately 15°, and a slight backward seat-pan, about 7°, may relieve muscle fatigue and provide more comfort while driving. Subsequently, according to the findings above, a preliminary driving-comfort function was constructed.

Musculoskeletal computational analysis on muscle mechanical characteristics of drivers lumbar vertebras and legs in different sitting postures

SUMMARY Using computer-aided engineering (CAE) in the concept design stage of automobiles has become a hotspot in human factor engineering research. Based on human musculoskeletal biomechanical computational software, a seated human-body musculoskeletal model was built to describe the natural sitting posture of a driver. The interaction between the driver and car in various combinations of seat-pan/back-rest inclination angles was analyzed using an inverse-dynamics approach. In order to find out the "most comfortable" driving posture of the seat-pan/back-rest, the effect of seat-pan/back-rest inclination angles on the muscle activity degree, and the intradiscal L4-L5 compression force were investigated. The results showed that a much larger back-rest inclination angle, approximately 15°, and a slight backward seat-pan, about 7°, may relieve muscle fatigue and provide more comfort while driving. Subsequently, according to the findings above, a preliminary driving-comfort function was constructed.

RESUMO O uso de engenharia assistida por computador (CAE) na fase de projeto do conceito do automóvel tornou-se um ponto de acesso na pesquisa de fatores humanos. Com base no software computacional biomecânico musculoesquelético humano, foi construído um modelo musculoesquelético sentado para descrever a postura sentada natural de um condutor. A interação entre um motorista e um carro em várias combinações de ângulos de inclinação do assento-pan/encosto foi analisada usando uma abordagem dinâmica do verso. A fim de descobrir a postura de condução "mais confortável" do assento-pan/encosto, o efeito dos ângulos de inclinação do assento-pan/dorso sobre o grau de atividade muscular e a força de compressão intradiscal L4-L5 foi investigado. Os resultados mostraram que um ângulo de inclinação para trás muito maior, aproximadamente 15°, e um ligeiro assento-pan para trás, cerca de 7°, pode aliviar a fadiga muscular e levar a dirigir em uma posição confortável. Posteriormente, de acordo com as conclusões acima expostas, foi construída uma função preliminar de conforto ao dirigir.

Janus Soft Actuators with On-Off Switchable Behaviors for Controllable Manipulation Driven by Oil.

Soft actuators have tremendous applications in diverse fields. Facile preparation, rapid actuation, and versatile actions are always pursued when developing new types of soft actuators. In this paper, we present a facile method integrating laser etching and mechanical cutting to prepare Janus actuators driven by oil. A Janus film with superhydrophobic and hydrophobic sides was fabricated successfully. By cutting the functional layer at the desired positions, a number of quintessential oil-driven soft devices were demonstrated. Furthermore, Janus actuators with surfaces of different wettabilities exhibited different swelling behaviors, and different media manifested different surface extensions; thus, these actuators are promising candidates for soft actuators and also realized on-off switchability between an oil/water mixture and ethanol. This study offers novel insight into the design of soft actuators, and this insight may be helpful for developing an oil-driven soft actuator that can be operated like a human finger to manipulate any object and extending stimuli-responsive applications for soft robotics.

Hispidulin induces ER stress-mediated apoptosis in human hepatocellular carcinoma cells in vitro and in vivo by activating AMPK signaling pathway.

Hispidulin (4',5,7-trihydroxy-6-methoxyflavone) is a phenolic flavonoid isolated from the medicinal plant S. involucrata, which exhibits anti-neoplastic activity against several types of cancer. However, the mechanism underlying its anti-cancer activity against hepatocellular carcinoma (HCC) has not been fully elucidated. In this study, we investigated whether and how hispidulin-induced apoptosis of human HCC cells in vitro and in vivo. We showed that hispidulin (10, 20 µmol/L) dose-dependently inhibited cell growth and promoted apoptosis through mitochondrial apoptosis pathway in human HCC SMMC7721 cells and Huh7 cells. More importantly, we revealed that its pro-apoptotic effects depended on endoplasmic reticulum stress (ERS) and unfolded protein response (UPR), as pretreatment with salubrinal, a selective ERS inhibitor, or shRNA targeting a UPR protein CHOP effectively abrogated hispidulin-induced cell apoptosis. Furthermore, we showed that hispidulin-induced apoptosis was mediated by activation of AMPK/mTOR signaling pathway as pretreatment with Compound C, an AMPK inhibitor, or AMPK-targeting siRNA reversed the pro-apoptotic effect of hispidulin. In HCC xenograft nude mice, administration of hispidulin (25, 50 mg/kg every day, ip, for 27 days) dose-dependently suppressed the tumor growth, accompanied by inducing ERS and apoptosis in tumor tissue. Taken together, our results demonstrate that hispidulin induces ERS-mediated apoptosis in HCC cells via activating the AMPK/mTOR pathway. This study provides new insights into the anti-tumor activity of hispidulin in HCC.

A bioinspired structured graphene surface with tunable wetting and high wearable properties for efficient fog collection.

Inspired by the fog harvesting ability of the spider net and the interphase wetting surface of Namib desert beetles, we designed a kind of special bioinspired hybrid wetting surface on a Cu mesh by combining polydimethylsiloxane (PDMS) and graphene (G). A surface containing hydrophobic and superhydrophobic areas is prepared by a combination of laser etching and ultrasonic vibration. Thus, this as-prepared hybrid wetting surface can quickly drive tiny water droplets toward more wettable regions, which makes a great contribution to the improvement of collection efficiency. Moreover, the PDMS/G surface not only is tolerant to many stresses such as excellent anti-corrosion ability, anti-UV exposure and oil contamination, but also shows self-healing simply by burning the worn areas, which thus endows the surface with tunable-wettability change between flame treatment and abrasive wear. This study offers a novel insight into the design of burned healed materials with interphase wettability that may enhance the fog collection efficiency in engineering liquid harvesting equipment and realizes renewable materials in situ cheaply and rapidly by processes that can be easily scaled and automated.

Hispidulin inhibits hepatocellular carcinoma growth and metastasis through AMPK and ERK signaling mediated activation of PPARγ.

Hispidulin, a phenolic flavonoid, exerts potent cytotoxicity towards a variety of human cancers. However, the effects of hispidulin on hepatocellular carcinoma (HCC) and underlying molecular mechanisms of its action remain elusive. The present study investigated the effect of hispidulin on HCC in experimental models, including tumor cell lines and mouse tumor xenograft. Results demonstrated that hispidulin was cytotoxic and anti-proliferative to HCC cell lines (SMMC7721 and Bel7402). Hispidulin activated caspase-3 and triggered apoptosis in HCC cells. Moreover, hispidulin inhibited cell migration and invasion by inhibiting the expression of matrix metalloproteinases (MMP-2, MMP-9) and by inducing tissue inhibitor of metalloproteinase-3 (TIMP-3) expression. Hispidulin activated peroxisome proliferator-activated receptor γ (PPARγ) signaling which mainly contributed to its cytotoxicity in HCC cells. Remarkably, GW9662 (a PPARγ inhibitor) or PPARγ targeting siRNA significantly abrogated the anti-proliferative, pro-apoptotic, and anti-metastatic effects of hispidulin in HCC cells. Furthermore, hispidulin induced activation of PPARγ which was associated with increased phosphorylation of AMPK, ERK, JNK in HCC cells. Compound C (an AMPK inhibitor) or PD98059 (a MEK inhibitor) partly reversed the effects of hispidulin on PPARγ signaling in HCC cells. In contrast, no significant changes in PPARγ signaling were observed in HCC cells pretreated with SP600125 (a JNK inhibitor), while SP6000125 significantly inhibited the anti-cancer effects of hispidulin in HCC cells. Hispidulin administration effectively suppressed Bel7402 xenograft tumor growth and lung metastasis in vivo. Our findings indicate that PPARγ activation by hispidulin effectively suppressed HCC cell growth and metastasis both in vitro and in vivo.

Temperature-tunable wettability on a bioinspired structured graphene surface for fog collection and unidirectional transport.

We designed a type of smart bioinspired wettable surface with tip-shaped patterns by combining polydimethylsiloxane (PDMS) and graphene (PDMS/G). The laser etched porous graphene surface can produce an obvious wettability change between 200 °C and 0 °C due to a change in aperture size and chemical components. We demonstrate that the cooperation of the geometrical structure and the controllable wettability play an important role in water gathering, and surfaces with tip-shaped wettability patterns can quickly drive tiny water droplets toward more wettable regions, so making a great contribution to the improvement of water collection efficiency. In addition, due to the effective cooperation between super hydrophobic and hydrophilic regions of the special tip-shaped pattern, unidirectional water transport on the 200 °C heated PDMS/G surface can be realized. This study offers a novel insight into the design of temperature-tunable materials with interphase wettability that may enhance fog collection efficiency in engineering liquid harvesting equipment, and realize unidirectional liquid transport, which could potentially be applied to the realms of microfluidics, medical devices and condenser design.

Bioinspired Fabrication of one dimensional graphene fiber with collection of droplets application.

We designed a kind of smart bioinspired fiber with multi-gradient and multi-scale spindle knots by combining polydimethylsiloxane (PDMS) and graphene oxide (GO). Multilayered graphene structures can produce obvious wettability change after laser etching due to increased roughness. We demonstrate that the cooperation between curvature and the controllable wettability play an important role in water gathering, which regulate effectively the motion of tiny water droplets. In addition, due to the effective cooperation of multi-gradient and multi-scale hydrophilic spindle knots, the length of the three-phase contact line (TCL) can be longer, which makes a great contribution to the improvement of collecting efficiency and water-hanging ability. This study offers a novel insight into the design of smart materials that may control the transport of tiny drops reversibly in directions, which could potentially be extended to the realms of in microfluidics, fog harvesting filtration and condensers designs, and further increase water collection efficiency and hanging ability.

Single dose administration of L-carnitine improves antioxidant activities in healthy subjects.

L-carnitine has been used as a supplement to treat cardiovascular or liver disease. However, there has been little information about the effect of L-carnitine on anti-oxidation capability in healthy human subjects. This study was designed to investigate the correlation between plasma L-carnitine concentration and antioxidant activity. Liquid L-carnitine (2.0 g) was administered orally as a single dose in 12 healthy subjects. Plasma concentration of L-carnitine was detected by HPLC. The baseline concentration of L-carnitine was 39.14 ± 5.65 µmol/L. After single oral administration, the maximum plasma concentration (C(max)) and area under the curve (AUC(0-∞)) were 84.7 ± 25.2 µmol/L and 2,676.4 ± 708.3 µmol/L·h, respectively. The half-life and the time required to reach the C(max) was 60.3 ± 15.0 min and 3.4 ± 0.46 h, respectively. There was a gradual increase in plasma concentrations of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase and total antioxidative capacity (T-AOC) in the first 3.5 h following L-carnitine administration. The plasma concentrations of SOD, GSH-Px, catalase and T-AOC returned to baseline levels within 24 h. A positive correlation was found between L-carnitine concentration and the antioxidant index of SOD (r = 0.992, P < 0.01), GSH-Px (r = 0.932, P < 0.01), catalase (r = 0.972, P < 0.01) or T-AOC (r = 0.934, P < 0.01). In conclusion, L-carnitine increases activities of antioxidant enzymes and the total antioxidant capacity in healthy subjects. It may be useful as a supplementary therapy for chronic illnesses involving excessive oxidative stress.

Comparison of pharmacokinetics of L-carnitine, acetyl-L-carnitine and propionyl-L-carnitine after single oral administration of L-carnitine in healthy volunteers.

PURPOSE: To investigate the pharmacokinetics of L-carnitine (LC) and its analogues, acetyl-L-carnitine (ALC) and propionyl-L-carnitine (PLC) in healthy volunteers after single L-carnitine administration. METHODS: Liquid L-carnitine (2.0 g) was administered orally as a single dose in 12 healthy subjects. Plasma and urine concentrations of L-carnitine, ALC and PLC were detected by HPLC. RESULTS: The maximum plasma concentration (Cmax) and area under the curve (AUC 0-infinity) of L-carnitine was 84.7+/-25.2 micromol x L(-1) x h and 2676.4+/-708.3 micromol x L(-1) x h, respectively. The elimination half-life of L-carnitine and the time required to reach the Cmax (Tmax) was 60.3+/-15.0 and 3.4+/-0.46 h, respectively. The Cmax of ALC (12.9+/-5.5 micromol x L(-1)) and PLC (5.08+/-3.08 micromol x L(-1)) was lower than L-carnitine (P < 0.01), so as the AUC 0-infinity (166.2+/-77.4 and 155.6+/-264.2 micromol x L(-1) x h, respectively, P < 0.01). The half-life of ALC (35.9+/-28.9h) and PLC (25.7+/-30.3 h) was also shorter than L-carnitine (P < 0.01). The 24h accumulated urinary excretion of L-carnitine, ALC and PLC were 613.5+/-161.7, 368.3+/-134.8 and 61.3+/-37.8 micromol, respectively. CONCLUSION: L-carnitine has a greater maximum plasma concentration than ALC and PLC. L-carnitine also has a longer half-life than ALC and PLC. These data may have important implications in the designing of dosing regimens for L-carnitine or its analogues, such as ALC or PLC.

Polypeptide from Chlamys farreri inhibits murine thymocytes apoptosis and modulates UVB induced signaling pathway activation.

Polypeptide from Chlamys farreri (PCF) has been identified as a potent antioxidant and photoprotective agent. In this study, we investigated whether PCF could inhibit apoptosis of murine thymocytes induced by ultraviolet B (UVB) and modulate UVB induced the mitogen-activated protein kinases (MAPKs) cascade in vitro. Our results show that PCF inhibit UVB-induced apoptotic cell death in murine thymocytes. We also found that PCF potently stimulated the phosphorylation of ERKs, which is involved in the cell survival-signaling cascade. Furthermore, the specific inhibition of the ERKs pathways by PD98059 reduced the cytoprotective effect of PCF. On the other hand, the JNKs and p38 inhibitor SP600125 and SB203580 additively enhanced the cytoprotective effect of PCF. We concluded that the activation of JNKs and p38 kinase played an important role in UVB-induced apoptosis, and PCF likely exerted its cytoprotective effect in thymocytes through ERKs activation. These suggested that part of the antiapoptotic effect of PCF might be mediated by its ability to modulate the MAPKs cascade.

Polypeptide from Chlamys farreri protects HaCaT cells from UVB-induced apoptosis.

A natural polypeptide from marine Chlamys farreri (a kind of scallop) (PCF), has been recently been found to be an effective photoprotective agent against ultraviolet rays B (UVB)-induced mitochondria damage in normal human fibroblasts. To investigate whether PCF has the antiapoptotic effect on human keratinocytes, in the present study, we established an apoptotic model on HaCaT cell line by means of UVB radiance of 30 mJ/cm(2) and compared the effect of different PCF treatments on UVB-radiated cells. Flow cytometry analyses showed that PCF treatment before UVB-irradiation inhibited UVB-induced apoptosis, the loss of mitochondrial membrane potential (Deltapsim) and the increase of free Ca(2+) level in HaCaT cells. In parallel with these results, UVB-irradiation enhanced activities of caspases-3, 8, 9, while this enhancement was inhibited by PCF treatment prior to irradiation. PCF added after irradiation neither reduced UVB-induced activities of the three caspases nor synergized the effect of pre-added PCF. Cellular ultrastructural features obtained from transmission electron microscopy further confirmed the antiapoptotic effect of PCF pre-treatment. It is concluded that the antiapoptotic effect of PCF is not therapeutic but prophylactic. Caspases-3, 8, 9, Deltapsim and calcium are involved in UVB-induced apoptosis, while prophylactic PCF inhibits apoptosis of UVB-irradiated HaCaT cells by blocking the caspases activities, the Deltapsim lost and the elevation of intracellular free Ca(2+) level.

Inhibitory effect of polypeptide from Chlamys farreri on ultraviolet A-induced oxidative damage on human skin fibroblasts in vitro.

We have previously reported that polypeptide from Chlamys farreri (PCF) inhibits the oxidative damage of ultraviolet A (UVA) on HeLa cells in vitro [Acta Pharm. Sin. 23 (2002) 961]. To further elucidate a possible role for PCF on UVA-damaged normal human cells, we established the oxidative damage models of normal human dermal fibroblasts (NHDF) exposed to UVA to study the protective effect of PCF on human dermal fibroblasts in vitro. In this study, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the cell viability. The intracellular superoxide dismutase (SOD), glutathione peroxidase (GSH-px), catalase (CAT), xanthine oxidase (XOD), malondialdehyde (MDA), reactive oxygen species (ROS), total antioxidative capacity (T-AOC), and anti-superoxide anion capacity (A-ASC) were measured. The effect of PCF on UVA-induced apoptosis were investigated by Annexin V-FITC assay. Intracellular calcium was determined with the calcium-sensitive fluorochrome Fluo-3, and mitochondrial transmembrane potential with rhodamine 123. Comet assay was employed to detect the UVA-induced DNA damage. The ultrastructure of cell was observed under transmission electron microscope. The results indicated that PCF could greatly enhance the viability of NHDF and markedly promote SOD, GSH-px, T-AOC, and A-ASC, while the amounts of MDA and ROS, the activity of XOD were decreased. PCF could inhibit UVA-induced apoptosis and DNA damage in NHDF. The concentration of cellular free calcium was decreased and the mitochondrial transmembrane potential was increased by PCF. In ultrastructure of NHDF, PCF could greatly decrease UVA-induced damage, especially membrane. Our results suggest that the supplementation of PCF appears to reduce the UVA-induced normal human dermal fibroblasts damage efficiently. It may be involved in the PCF's abilities of scavenging oxygen free radical, inhibiting lipid peroxidation, increasing antioxidative enzymes, decreasing intracellular calcium and protection of membrane structure in NHDF irradiated by UVA.