Convecting particle diffusion in a binary particle system under vertical vibration.

We studied the separation behaviour of binary granular particles in a vertically vibrated container. The final separation of the binary particle system exhibited the Brazil-Nut (BN) effect, though it was not complete. Particle convection occurred, and four different typical convection modes were observed when the frequency f changed from 20 Hz to 80 Hz at constant dimensionless acceleration Γ = 4πAf(2)/g. However, when Γ changed from 2 to 4 at constant f, the system's convection mode stayed almost the same. In our experiments, one type of particle generally moved much faster than the other, so the former was termed the 'convecting' particle, and the latter was termed the 'non-convecting' particle. To study the separation results qualitatively, we divided the system into vertical layers and calculated the mass distribution of the binary particles along the z axis. The results showed that when f increased at constant Γ or Γ decreased at constant f, the convecting particles, usually the smaller and lighter ones, distributed less to the top side and more to the bottom side of the container. Finally, to explain the experimental results, we derived a mass conservation equation for the convecting particles considering simultaneous convection and diffusion. The equation described the experimental results well. We also analysed the effects of f, Γ, diameter ratio, density ratio, etc., on the final separation results.

[Establishment of a novel mouse mode of elastase-induced chronic obstructive pulmonary disease related osteoporosis].

OBJECTIVE: To establish and evaluate the model of chronic obstructive pulmonary disease (COPD) with osteoporosis induced by elastase in mice. METHODS: Twenty four healthy female 8-week-old C57BL / 6 mice (weighing about 18 g) were randomly divided into three groups. The control group was given intratracheal drip of normal saline, the experimental group 1 and the experimental group 2 were given intratracheal drip of elastase, the control group and the experimental group 1 were kept for 8 weeks and then killed, the experimental group 2 was kept for 12 weeks and then killed. HE staining was used to evaluate the histopathological changes of lung and tibia in the control and experimental groups. The levels of serum inflammatory factors and broncho alveolar lavage factors (BALF) were detected by ELISA. Micro CT was used to detect the bone mass related parameters of mouse femur. The expression of osteoclastic and osteogenic genes was detected by real-time fluorescence quantitative PCR. RESULTS: Lung histopathology showed that the structure of alveoli in the experimental group was disordered, the walls of alveoli became thin or broken, and the alveoli cavity expanded. IL-6 and TNF-α in BALF were significantly higher than those in control group (P<0.001), while IL-1ß and TNF-α in serum inflammatory factors were significantly higher than those in control group (P<0.001). BV / TV(bone volume fraction), TB.Th(average bone trabecular thickness) and TB.N(average bone trabecular number) in the experimental group were significantly lower than those in the control group (P<0.05), TB.Sp (average bone trabecular separation) and BS / BV (bone surface area fraction) in the experimental group were significantly higher than those in the control group (P<0.01). Compared with the control group, the expression of osteoclast related marker genes increased in the experimental group (P<0.05), but decreased in the experimental group(P<0.05). The results of experiment 1 and experiment 2 were time-dependent. CONCLUSION: In this study, elastase was used to construct a COPD model with osteoporosis successfully, which provides a suitable animal model for the future study of the pathogenesis of COPD with osteoporosis.

A Novel Diterpenoid Suppresses Osteoclastogenesis and Promotes Osteogenesis by Inhibiting Ifrd1-Mediated and IκBα-Mediated p65 Nuclear Translocation.

Osteoporosis develops because of impaired bone formation and/or excessive bone resorption. Although the pharmacological treatment of osteoporosis has been extensively developed, alternative treatments are still needed. Here, we showed that oridonin (ORI), a diterpenoid isolated from Rabdosia rubescens, can suppress osteoclastogenesis and enhance osteogenesis. ORI inhibited the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast formation and bone resorption through the inhibition of p65 nuclear translocation. ORI-induced inhibition of this translocation led to an increase in osteoblast differentiation and mineralization through the promotion of Smad1/Smad5 phosphorylation. Further analyses demonstrated that the inhibition of p65 nuclear translocation is due to the suppression of IκBα phosphorylation and the induced proteasomal degradation of interferon-related development regulator 1 (Ifrd1), a transcriptional corepressor that is involved in the suppression of NF-κB nuclear translocation. Moreover, mice treated with ORI at catabolic and anabolic windows showed a considerable attenuation of ovariectomy (OVX)-induced osteoporosis. Taken together, our findings reveal that ORI protects against OVX-induced bone loss via inhibiting osteoclastic bone resorption but enhancing osteoblastic bone formation through abolishing both Ifrd1-mediating and IκBα-mediated p65 nuclear translocation. These results show the potential of ORI for treatment of osteoporosis and highlight Ifrd1 as a another novel promising target for anti-osteoporotic drugs. © 2017 American Society for Bone and Mineral Research.

Bone-targeted methotrexate-alendronate conjugate inhibits osteoclastogenesis in vitro and prevents bone loss and inflammation of collagen-induced arthritis in vivo.

Rheumatoid arthritis (RA), a disease that causes joint destruction and bone erosion, is related to osteoclast activity. RA is generally treated with methotrexate (MTX). In this study, a MTX-Alendronate (ALN) conjugate was synthesized and characterized. The conjugate dramatically inhibited osteoclast formation and bone resorption compared with MTX and ALN used alone or in combination. Due to the characteristics of ALN, the MTX-ALN conjugate can adhere to the exposed bone surface and enhance drug accumulation in the pathological region for targeted therapy against osteoclastogenesis. Additionally, MTX was rapidly released in the presence of lysozyme under mildly acidic conditions, similar to inflammatory tissue and osteoclast-surviving conditions, which contributes to inflammatory inhibition; this was confirmed by the presence of pro-inflammatory cytokines. Our study highlights the use of the MTX-ALN conjugate as a potential therapeutic approach for RA by targeting osteoclastogenesis.

Honokiol alleviates the degeneration of intervertebral disc via suppressing the activation of TXNIP-NLRP3 inflammasome signal pathway.

Intervertebral disc degeneration (IVDD) is a multifactorial disease and responsible for many spine related disorders, causes disability in the workforce and heavy social costs all over the world. Honokiol, a low molecular weight natural product, could penetrate into and distribute in IVDs to achieve therapeutic effect in a rat tail model. Therefore, the present study was undertaken to examine the antiinflammatory, antioxidation and IVD-protective effect of honokiol using nucleus pulposus cells and investigate its mechanisms to provide a new basis for future clinical treatment of IVDD. In the current study, we demonstrated that honokiol inhibits the H2O2-induced apoptosis (caspase-9, caspase-3, and bax), levels of oxidative stress mediators (ROS, MDA), expression of inflammatory mediators (Interleukin-6, COX-2, and iNOS), major matrix degrading proteases (MMP-3, MMP-13, ADAMTS5, and ADAMTS4) associated with nucleus pulposus degradation. Furthermore, we found nucleus pulposus protective ability of honokiol by up-regulating extra cellular matrix anabolic factors like type II collagen (Col II) and SOX9 in nucleus pulposus. We also found that honokiol suppressed the phosphorylation of NF-kB and JNK, and activation of TXNIP-NLRP3 inflammasome in H2O2-stimulated nucleus pulposus cells, thereby inhibiting the activation of downstream inflammatory mediators such as Interleukin-1ß. Furthermore, honokiol showed a cartilage protective effect in the progression of IVDD in a rat model induced by puncture. Thus, our results demonstrate that honokiol inhibited the H2O2 induced apoptosis, oxidative stress, and inflammatory responses through the depression of TXNIP/NLRP3/caspase-1/ Interleukin - 1ß signaling axis and the activation of NF-kB and JNK. Honokiol possess nucleus pulposus protective properties and may be of value in suppressing the pathogenesis of IVDD.

Raddeanin A suppresses breast cancer-associated osteolysis through inhibiting osteoclasts and breast cancer cells.

Bone metastasis is a severe complication of advanced breast cancer, resulting in osteolysis and increased mortality in patients. Raddeanin A (RA), isolated from traditional Chinese herbs, is an oleanane-type triterpenoid saponin with anticancer potential. In this study, we investigated the effects of RA in breast cancer-induced osteolysis and elucidated the possible mechanisms involved in this process. We first verified that RA could suppress osteoclast formation and bone resorption in vitro. Next, we confirmed that RA suppressed Ti-particle-induced osteolysis in a mouse calvarial model, possibly through inhibition of the SRC/AKT signaling pathway. A breast cancer-induced osteolysis mouse model further revealed the positive protective effects of RA by micro-computed tomography and histology. Finally, we demonstrated that RA inhibited invasion and AKT/mammalian target of rapamycin signaling and induced apoptosis in MDA-MB-231 cells. These results indicate that RA is an effective inhibitor of breast cancer-induced osteolysis.

Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy After Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model.

STUDY DESIGN: A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery. OBJECTIVE: We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model. SUMMARY OF BACKGROUND DATA: Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles. METHODS: Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 hours. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration, or fibrosis of multifidus muscle were evaluated by quantitative real-time polymerase chain reaction (q-PCR), histology, or immunohistochemical analysis. RESULTS: T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively. CONCLUSION: In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles. LEVEL OF EVIDENCE: N/A.

Granular core phenomenon induced by convection in a vertically vibrated cylindrical container.

A mixture of 13X molecular sieve (13XMS) particles and glass particles with identical diameters is placed in a cylindrical container. Under vertical vibration, heavier glass particles tend to cluster and are wrapped inside the convection of 13XMS particles, resulting in the granular core phenomenon. The vibration frequency f strongly influences particle convection and particle cluster modes. By contrast, the effect of the dimensionless acceleration amplitude Γ can be neglected. For different f ranges, the granular core is classified as center-type and ring-type cores. For the center-type core, heavy particles are distributed as an approximate zeroth-order Bessel function of the first kind in the radial direction and an exponential function in the height direction. For the ring-type core, the concentration of heavy particles follows the power-series function in the radial direction. A granular transport model is then established based on heavy-particle movements under steady state to analyze the effect of vibration parameters and granular convection on density segregation.

Separation patterns between Brazilian nut and reversed Brazilian nut of a binary granular system.

This paper studies the segregation behavior of binary granular particles with diameters at approximately 10:1 in a vertically vibrated container. An array of transitional separation patterns between reversed Brazilian nut (RBN) and Brazilian nut (BN) separations are observed, with their geometrical features carefully measured. The binary particle system develops into either a stable separation pattern when f and Γ are relatively low or an oscillating pattern when f and Γ are relatively high. We regard these patterns as different phases, in which the stable patterns can be divided into phases of RBN, RBN transitional (RBNT), BNT, and BN. A phase parameter λ between-1 and 1 is defined to describe the separation patterns based on the mass center height difference in large and small particles. By drawing f-Γ-λ phase diagrams, the system's tendency toward BN separation was found to increase with f and decrease with Γ. Furthermore, the range of the tendency toward BN separation expands when the size of small particles rises. As the total mass of the small particles increases, the system's tendency toward RBN separation is enhanced. Abnormal points are also observed in the stable phase regions, and the oscillating phase shifts among the four stable phases with time. These stable phases can be explained via an analysis of the distribution of the dissipation energy, whereas the mechanism of the oscillating phase remains to be discovered.