Rejuvenation Effects Research Articles

Combined effect of waste polymer and rejuvenator on performance properties of reclaimed asphalt binder

In hot asphalt recycling, use of reclaimed asphalt binder has resulted in stiffer binders. To counter this phenomenon, rejuvenators are utilized. Further, research has shown that polymers can improve the performance properties of the aged bitumen. The study of the combined effect of both (rejuvenator and polymer) on the rheological properties of reclaimed asphalt binder can provide useful insights about the performance of the binder in hot asphalt recycling projects. In the current study, the combined effect of a rejuvenator and polymer derived from a waste source on the mechanical properties of bitumen containing varying percentages of reclaimed asphalt binder (RAB) is evaluated for the first time. The fatigue behavior was evaluated using linear amplitude sweep (LAS), and time sweep (TS) tests while rutting resistance was assessed using multiple stress creep recovery (MSCR) test. Moreover, bending beam rheometer (BBR) test is also performed to compare the sample’s low-temperature cracking. Results indicate that the synergistic use of waste polymer along with rejuvenator substantially improves the high, intermediate, and low-temperature properties of the blends with 50% RAB content compared to that of the control bitumen. Therefore, the use of waste PBR in hot asphalt recycling (HIR) projects, in addition to improving the performance of recycled bitumen can also be introduced as an environmental-friendly option.

On the magnetic ground state of lead-free complex perovskite Sr(Fe1/2Nb1/2)O3

We present here the results of dc magnetization (M) measurements as a function of temperature (T), field (H) and time (t) with different histories and ac susceptibility measurements as a function of temperature and frequency to understand the magnetic ground state of Sr(Fe1/2Nb1/2)O3 (SFN). We show that the zero-field cooled (ZFC) and field cooled (FC) magnetization curves (M(T)) not only bifurcate but also exhibit a short plateau with a dip in the FC M(T) curve suggesting that the observed history dependent irreversibility may be due to cluster spin-glass (CSG) freezing and not superparamagnetic (SPM) blocking. This is confirmed by ac susceptibility χ(ω, T) studies which reveal critical slowing down of the spin dynamics as per Vogel Fulcher and power laws with spin-glass transition temperature TSG ∼(24 ± 1) K. The attempt time obtained by these laws (τ0 ∼10−6 s) is found to be consistent with CSG picture. Further, the field dependent shift of Tf follows de Almeida-Thouless line in the T-H plane with a characteristic critical exponent m = 2/3. Further support for the existence of the spin-glass phase is obtained by the observation of non-exponential decay of the thermoremanent magnetization as well as aging, rejuvenation and memory effects below Tf. The non-zero value of remanent magnetization Mr without saturation below Tf is shown to vanish exponentially with increasing temperature as T → TSG in agreement with what is observed in spin-glass systems. We also present a critical comparison of the magnetic ground states of SFN with CaCu3Ti4O12 (CCTO) and other complex niobate perovskites in terms of the strength of the nearest neighbour exchange interaction parameter J1, the coordination polyhedral, the disorder/dilution level of the magnetic sublattices, the presence or absence of octahedral tilts and the possibility of alternative superexchange pathways in these compounds.

Postinflammatory and rebound hyperpigmentation as a complication after treatment efficacy of telangiectatic melasma with 585 nanometers Q-switched Nd: YAG laser and 4% hydroquinone cream in skin phototypes III-V.

The potential efficacy of vascular component-targeted laser has been evaluated for the treatment of melasma, which commonly found with the co-existence of telangiectasia. To evaluate the treatment efficacy and safety of 585-nm QSNYL and 4% HQ cream combination vs 4% HQ cream alone for telangiectatic melasma in the skin phototypes III-V. Twenty-one Thai female patients with telangiectatic melasma and Fitzpatrick skin phototypes (FPTs) III-V were randomly treated with the 585-nm QSNYL on one side of the face for five sessions at 2-week intervals. All patients were assigned to apply HQ cream daily at night on both sides of the face for 10 weeks and a broad-spectrum sunscreen regularly throughout the study. The treatment efficacy and safety were evaluated using the Modified Melasma Area and Severity Index (mMASI), biometric evaluation, patient assessment, and adverse effects. The combination-treated side yielded more significant improvement of mMASI than the topical-treated side at weeks 2, 4, and 8, respectively. However, 19% of the patients developed postinflammatory hyperpigmentation (PIH) on the laser-treated side, especially in FPTs IV-V and rebound hyperpigmentation. There was a significant improvement of hemoglobin and melanin index, but without statistical difference between the two treatment groups. The combination of 585-nm QSNYL and HQ treatment yields treatment efficacy and skin rejuvenation effects for telangiectatic melasma. Nonetheless, a high incidence of PIH and rebound hyperpigmentation is adversely developed in dark FPT. Thus, this laser treatment should be cautiously applied in those with dark FPTs IV-V to avoid laser-induced pigment alteration.

Mapping the Viscoelastic Heterogeneity at the Nanoscale in Metallic Glasses by Static Force Spectroscopy.

Nanoscale viscoelastic heterogeneity is an important concept for understanding the relationship between the microscopic atomic structure and the macroscopic mechanical behaviors in metallic glasses. However, the direct measurement of viscoelastic behavior at the nanoscale is still missing. Here we report a new measurement method based on static force microscopy to directly measure the viscoelastic properties at the nanoscale. The observed adhesive force and elastic modulus maps clearly display a typical hierarchical viscoelastic microstructure consisting of local hard and soft regions. Moreover, the adhesive force is more sensitive than the elastic modulus to viscoelastic heterogeneity and exhibits a bimodal distribution. In addition, we found that the structural relaxation and the rejuvenation effects induce the transition between the solid-like and liquid-like modes. The new measurement technique provides a powerful and quantative tool to investigate the nanoscale heterogeneity and build a connection between the microscopic structure and macroscopic mechanical behaviors in amorphous materials.

Engineered Heterochronic Parabiosis in 3D Microphysiological System for Identification of Muscle Rejuvenating Factors.

Exposure of aged mice to a young systemic milieu revealed remarkable rejuvenation effects on aged tissues, including skeletal muscle. Although some candidate factors have been identified, the exact identity and the underlying mechanisms of putative rejuvenating factors remain elusive, mainly due to the complexity of in vivo parabiosis. Here, we present an in vitro muscle parabiosis system that integrates young- and old-muscle stem cell vascular niche on a three-dimensional microfluidic platform designed to recapitulate key features of native muscle stem cell microenvironment. This innovative system enables mechanistic studies of cellular dynamics and molecular interactions within the muscle stem cell niche, especially in response to conditional extrinsic stimuli of local and systemic factors. We demonstrate that vascular endothelial growth factor (VEGF) signaling from endothelial cells and myotubes synergistically contribute to the rejuvenation of the aged muscle stem cell function. Moreover, with the adjustable on-chip system, we can mimic both blood transfusion and parabiosis and detect the time-varying effects of anti-geronic and pro-geronic factors in a single organ or multi-organ systems. Our unique approach presents a complementary in vitro model to supplement in vivo parabiosis for identifying potential anti-geronic factors responsible for revitalizing aging organs.

Evaluating the Chemical and Rheological Attributes of Aged Asphalt: Synergistic Effects of Maltene and Waste Engine Oil Rejuvenators

The service life of road pavement reduces as it ages and loses its properties due to the exposure to varying traffic loads and climatic conditions. This study explores the potential rejuvenation of the aged asphalt properties to enable it to be reused in pavement by adding hybrid rejuvenator (WEO-MLT). The WEO-MLT is composed of waste engine oil and maltene (MLT). Four types of binders, namely virgin asphalt, aged asphalt, 40% aged asphalt and rejuvenated asphalt, were prepared and evaluated via rheological and chemical tests [e.g. storage stability, asphaltene-to-MLT ratio, dynamic shear rheometer, bending beam rheometer, Fourier transform infrared (FTIR), thermogravimetric analysis and stripping resistance tests]. The results revealed that the WEO-MLT markedly enhanced the properties of aged asphalt at low and high temperatures. In contrast, the outcomes of FTIR suggested that the ageing properties of asphalt were not improved significantly by WEO-MLT due to the presence of a carboxyl group in its composition. TGA indicated that the initial decomposition for rejuvenated asphalt was approximately close to virgin asphalt. The stripping resistance test divulged the comparable performance of the rejuvenated asphalt to that of virgin asphalt. Therefore, WEO-MLT can be potentially used in the rejuvenation of the aged asphalt, paving the way to sustainable and eco-friendly asphalt production.

Long Term Effects of Combination of Metabolite Product Amniotic Membrane Stem Cell (MP-AMSC) and Vitamin C after Fractional CO2 Laser for Photoaging Treatment

Background: Metabolite Products Amniotic Membrane Stem Cell (MP-AMSC) originating from the amniotic membrane has a skin rejuvenation effect by stimulating collagen synthesis. Vitamin C functions as an antioxidant in photoaging treatment. It is expected that the application of a combination of MP-AMSC and vitamin C after fractional CO2 laser treatment as Laser-Assisted Drug Delivery (LADD) to provide better long-term effects on clinical improvement of photoaged skin. As the drug penetration reaching the target, long-term effects and no side effects are expected. This promises as an option for photoaging therapy in the future. Purpose: This study aimed to evaluate the long-term effects of a combination of topical MP-AMSC mixtures and vitamin C after fractional CO2 laser treatment on wrinkles, spots, pores, and skin tones. Methods: Thirty adult women with photoaged skins were selected as samples, and were observed for wrinkles, spots, pores, and skin tones examination. The observation involved computer-simulated photographic devices, Facial Skin Scope System Janus-II for three months after the topical administration of MP-AMSC mixture and vitamin C, three times fractional CO2 laser, tretinoin 0.025% cream, and sun protection factor (SPF) 30 sunscreen as maintenance therapy. Result: The data analysis result was not statistically significant (p>0.05). Conclusion: There was a long-term effect of the application of a mixture of topical MP-AMSC and vitamin C after fractional CO2 laser treatment, and no side effect was observed.

The Efficacy of Topical Combination Amniotic Membrane Stem Cell Metabolite Product (AMSC-MP) and Vitamin E after Microneedling in Photoaging

Background: Photoaging, also called extrinsic aging, is a premature skin aging mainly resulting from prolonged and extended exposure to ultraviolet (UV) radiation. Amniotic Membrane Stem Cell Metabolite Products (AMSC-MP) are derived from amniotic membranes that contain cytokines and growth factors that have a role in the skin rejuvenation process. Vitamin E is an antioxidant that has a photoprotective effect, so it is expected to reduce the appearance of clinical signs of photoaging. Not only having skin rejuvenation effect, but microneedling is also expected to facilitate the penetration to increase the efficacy of AMSC-MP and vitamin E. This combination is expected to have a better effect on clinical photoaging improvement. Purpose: To evaluate the effect of a topical combination of AMSC-MP and vitamin E after microneedling on the clinical improvement of photoaging compared to previous skin conditions. Methods: Thirty adult women with photoaging topically administered a combination of AMSC-MP and vitamin E after 3 microneedling sessions at 2 weeks intervals. The evaluation of the improvement of the degree of pores, wrinkles, skin tone and dark spots were performed with the Janus-II Facial Skin Scope System. Result: There was a clinical improvement with a statistically significant difference in terms of the degree of pores, wrinkles, polarized black spots, and UV black spots, which were statistically significant differences (p <0.05). Conclusion: The administration of a topical combination of AMSC-MP and vitamin E after microneedling provided clinical improvement in photoaging as supported by the results of Janus analysis of pores, wrinkles, skin tones, polarized black spots, and UV black spots.

Reentrant spin glass state induced by structural phase transition in La0.4Ce0.6Co2P2

We have carried out a comprehensive investigation of magnetic properties of LuFe$_2$O$_4$, using AC susceptibility, DC magnetization and specific heat. A magnetic phase transition around $\sim$236 K was observed with DC magnetization and specific heat measurements, which is identified as a paramagnetic to ferrimagnetic transition based on the nonlinear susceptibility data. Upon further cooling below this temperature, we also observed highly relaxational magnetic behavior: the DC magnetization exhibits history and time dependence, and the real and imaginary part of the AC susceptibility shows large frequency dependence. Dynamic scaling of the AC susceptibility data suggests that this low temperature phase can be described as a reentrant spin glass phase. We also discuss magnetic field dependence of the spin glass transition and aging, memory and rejuvenation effect below the glass transition temperature around 228 K.

Preparation and characterization of active rejuvenated SBS modified bitumen for the sustainable development of high-grade asphalt pavement

To fully restore the performance of waste SBS modified asphalt mixture, better realize its recycling and application in high-grade pavement, achieve the concept of sustainable green development of asphalt pavement. In this paper, the synergistic effects of bio-rejuvenator and active isocyanate rejuvenators (including hexamethylene diisocyanate (HDI), diphenyl-methane-diisocyanate (MDI) and toluene-2, 6-diisocyanate (TDI)) on the chemical structure, physical and rheological properties of aged SBS modified bitumen were thoroughly investigated. Fourier infrared spectrum and Gel permeation chromatography analysis indicate the isocyanate groups of active rejuvenators react with hydroxyl or carboxyl group from the degraded SBS segments to form new amide groups that can reconnect the broken segments of aged SBS and partly restore its molecular weight distribution. From physical and rheological properties, bio-rejuvenator can restore the low-temperature properties by rebalancing the colloidal structure of aged binder, meanwhile, active rejuvenators can greatly improve the high-temperature performance of rejuvenated SBS modified bitumen with bio-rejuvenator through reconnecting the broken segments of aged modifier SBS. Furthermore, MDI with benzene ring structure is more conducive to enhancing the high temperature rutting resistance of rejuvenated SBS modified bitumen. While HDI can bring some flexible segments into the restored structure of SBS, which is more beneficial to improve its low-temperature cracking resistance of rejuvenated binder. And the fluorescence images further demonstrate isocyanate rejuvenators can partly restore the crosslinking network structure of aged modifier SBS in rejuvenated SBS modified bitumen. This research would be conductive to promoting the application of rejuvenated SBS modified bitumen into the construction of high standard pavement.

Investigation on rejuvenation methods of aged SBS modified asphalt binder

SBS modified asphalt binder (SBSMA) is widely used because of its excellent pavement performance. Recycling application for aged SBSMA has drawn increasing attention. In this study, aged SBSMA was rejuvenated with different rejuvenation methods, including the use of rejuvenator (RA), original SBSMA, base asphalt (SK-70) and original SBSMA mixed with SK-70. The conventional performance and rheological behavior of different rejuvenated SBSMA were investigated. The microscopic changes were analyzed by using Gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy and Fluorescence microscopy (FM). Results revealed that RA and original SBSMA have significant effect on the improvement of the physical-rheological and microstructures of aged SBSMA, but SK-70 did not exhibit good rejuvenation effect. The conventional tests showed that the addition of RA greatly improved the low temperature ductility and elastic recovery rate of aged SBSMA. Moreover, it was proved that RA could increase the creep compliance and improve the stress relaxation ability of aged SBSMA according to physical rheological parameters. This result indicated that RA improved the cracking resistance of aged SBSMA at low temperature. Based on the microscopic test results, it was found that RA not only could regulate the internal components of aged SBSMA, but also restore the network structure of aged SBSMA. Furthermore, the SBS polymer content indices and the softening indices are closely correlated with the performances of the rejuvenated SBSMA. From the analysis, it is necessary to rejuvenate the aged SBSMA by softening base asphalt and restoring the network structure of SBS copolymer.

Spin glass transition of single-crystalline TmFe2O4−δ

TmFe2O4 is one kind of multiferroic material in which equivalent amounts of Fe2+ and Fe3+ occupy a two-dimensional triangular lattice, leading to charge and spin frustrations. The spin frustration is expected to be increased as the fraction of Fe2+ (Fe3+) becomes larger than that of Fe3+ (Fe2+). We have grown single-crystalline TmFe2O4−δ with oxygen vacancies by using floating zone melting method and examined its magnetic properties. On cooling the compound, a long-range magnetic ordering develops around ∼240 K. With further cooling, a maximum of zero-field-cooled (ZFC) magnetization is observed at 186.2 K. The ac magnetic susceptibility obtained by ZFC process also manifests a maximum in its temperature dependence, and the variation of spin-freezing temperature with frequency of ac magnetic field is explainable in terms of the dynamic scaling law with the critical component of 8.68(8). This value suggests that the spin glass transition occurs at 186.2 K. The effect of external dc magnetic field on the irreversible transition temperature is coincident with the de Almeida–Thouless (AT) line. Aging-memory and rejuvenation effect is also observed below the spin-freezing temperature. These facts support the idea that TmFe2O4−δ undergoes spin glass transition below the ferrimagnetic transition temperature. In other words, TmFe2O4−δ can be regarded as a reentrance spin glass. It is thought that the oxygen vacancies bring about unequal number of Fe2+ and Fe3+ ions and thereby strengthen the magnetic frustration among the iron ions coupled with antiferromagnetic interactions, leading to the spin glass behavior.

Histological characterization of age-related skin changes following the use of picosecond laser: Low vs high energy.

Fractional lasers have become widespread in dermatology owing to their efficacy and safety. Comparative analysis of histological features after laser rejuvenation using a 1064-nm fractionated handpiece picosecond laser with different energy fluence levels (1.1 or 2.1 J/cm2 ). An open-label, study of 28 women aged 36 to 60 years with signs of age-related photodamage and skin changes of the face and neck was conducted using a fractional picosecond 1064 nm laser in low vs high fluence. The clinical assessment at 3 weeks showed more pronounced effect on facial skin rejuvenation with the higher fluence of 2.1 J/cm2 compared to 1.1 J/cm2 . The effect and safety of laser rejuvenation using a picosecond laser has been shown with more pronounced histological effects at higher fluences.

A techno-practical method for overcoming the biotoxicity and volatility obstacles of butanol and butyric acid during whole-cell catalysis by Gluconobacter oxydans

BackgroundButyric acid is a platform chemical material, the production of which has been greatly stimulated by the diverse range of downstream applications in many industries. In particular, higher quality butyric acid used in food and medicine, is more dependent on microbiological production methods. Hence, the bio-oxidation of butanol to butyric acid has been identified as a promising method with good potential economic and environmental benefits. However, both butanol and butyric acid are usually intensively toxic to most microorganisms as well as the bio-oxidation pathway. To develop a green, efficient and competitive microbiological method is the primary work to overcome the bottleneck of butyric acid industry.ResultA combined bioprocess was designed with alternative whole-cell catalysis for butyric acid bio-conversion from butanol by Gluconobacter oxydans in a sealed-oxygen supply bioreactor (SOS). In the operation system, the escape of volatile substrates and toxic chemicals to cells can be avoided by the use of a sealed bioreactor, combined with the rejuvenation of cells by supplying energy co-factors. Finally, during a one-batch whole-cell catalysis, the utilization rate of substrate increased from 56.6 to 96.0% by the simple skill. Additionally, the techno-practical bioprocess can realize the purpose of cell-recycling technology through the rejuvenation effect of co-factor. Finally, we obtained 135.3 g/L butyric acid and 216.7 g/L sorbose during a 60-h whole-cell catalysis. This techno-practical technology provides a promising approach to promote the industrial production of butyric acid with more competitiveness.ConclusionThe techno-practical biotechnology has powerfully promoted the process of butyric acid production by microorganisms, especially makes up for the lack of aerobic fermentation in the industry, and surmounts the shortcomings of traditional anaerobic fermentation. At the same time, this technically practical system provides a promising approach for the promotion of the industrial production of butyric acid in a more competitive manner.

Exercise Partially Rejuvenates Muscle Stem Cells

Exercise has long been known to extend health and lifespan in humans and other mammals. However, typically exercise is thought to slow the loss of function that accompanies aging. Brett et al. have now shown that exercise restores functional competency to regenerate muscle stem cells (MuSCs) in mice as well as restore a significant portion of the transcriptional signature associated with young MuSCs. The mechanism involves the likely induction of plasma-borne factors that upregulate cell cycle regulator cyclin D1, which otherwise decreases with increasing age. Cyclin D1, in turn, through its noncanonical attenuation of TGF-beta/Smad3 signaling, helps maintain the regenerative capacity of MuSCs, which is lost as TGF-beta signaling increases with age. Interestingly, elevated levels of some proinflammatory regulators including NF-κB, TNF-alpha, and interleukin 6 (IL-6) are also reduced by exercise or ectopic expression of cyclin D1. Importantly, the rejuvenation is not complete, as Notch signaling, which also decreases with age, remains at old levels and the rejuvenative effect is not permanent: wearing off in ∼2 weeks after cessation of exercise. Understanding the limitations of the rejuvenative effect of exercise on MuSCs at the molecular level, including changes in the epigenome such as altered DNA methylation age, will be critical in developing more significant rejuvenative therapies including some for aged people wherein morbidities limit exercise.

Rejuvenation of three germ layers tissues by exchanging old blood plasma with saline-albumin.

Heterochronic blood sharing rejuvenates old tissues, and most of the studies on how this works focus on young plasma, its fractions, and a few youthful systemic candidates. However, it was not formally established that young blood is necessary for this multi-tissue rejuvenation. Here, using our recently developed small animal blood exchange process, we replaced half of the plasma in mice with saline containing 5% albumin (terming it a “neutral” age blood exchange, NBE) thus diluting the plasma factors and replenishing the albumin that would be diminished if only saline was used. Our data demonstrate that a single NBE suffices to meet or exceed the rejuvenative effects of enhancing muscle repair, reducing liver adiposity and fibrosis, and increasing hippocampal neurogenesis in old mice, all the key outcomes seen after blood heterochronicity. Comparative proteomic analysis on serum from NBE, and from a similar human clinical procedure of therapeutic plasma exchange (TPE), revealed a molecular re-setting of the systemic signaling milieu, interestingly, elevating the levels of some proteins, which broadly coordinate tissue maintenance and repair and promote immune responses. Moreover, a single TPE yielded functional blood rejuvenation, abrogating the typical old serum inhibition of progenitor cell proliferation. Ectopically added albumin does not seem to be the sole determinant of such rejuvenation, and levels of albumin do not decrease with age nor are increased by NBE/TPE. A model of action (supported by a large body of published data) is that significant dilution of autoregulatory proteins that crosstalk to multiple signaling pathways (with their own feedback loops) would, through changes in gene expression, have long-lasting molecular and functional effects that are consistent with our observations. This work improves our understanding of the systemic paradigms of multi-tissue rejuvenation and suggest a novel and immediate use of the FDA approved TPE for improving the health and resilience of older people.

Microscopic examination of rejuvenated binders with high reclaimed asphalts

A properly formulated rejuvenator is a possible remedy for asphalt pavements with a high percentage of Reclaimed Asphalt Pavement (RAP), which is traditionally too stiff to resist premature damage due to fatigue cracking. Rejuvenated asphalt binders with high RAP have traditionally been evaluated by micro- and macro-level test methods, which are transcendental in providing binders’ molecular level properties that govern their performance properties. This paper presents the usefulness of an Atomic Force Microscope (AFM) and its nanoindentation technique to observe morphological and nanomechanical properties of rejuvenated asphalt binders with high RAP. A commercial rejuvenator is applied in a Performance Grade (PG) (PG 64-22) binder blended with different percentages (25%, 40%, and 60%, by the weight of the blended binder) of a bulk RAP. The rejuvenated asphalt binder blends were subjected to routine tests such as Penetration, Rotational Viscosity (RV), and Dynamic Shear Rheometer (DSR) as well as the AFM-based PeakForce Quantitative Nanomechanical Mapping (PFQNM™) analysis. As expected, the routine test results reveal that the rejuvenator reduces the stiffness of the RAP-modified binders. The effects of rejuvenator on the RAP-blended binders are evident in the morphological images and nano-level mechanistic data. Based on the AFM test results, it is observed that modulus values of RAP blended binders reduced significantly when the rejuvenator was used. The findings of this study will benefit the pavement professionals for assessing the effectiveness of rejuvenators in asphalt binders with high RAP contents.

Cretaceous continental margin evolution revealed using quantitative seismic geomorphology, offshore northwest Africa

AbstractThe application of high‐resolution seismic geomorphology, integrated with lithological data from the continental margin offshore The Gambia, northwest Africa, documents a complex tectono‐stratigraphic history through the Cretaceous. This reveals the spatial‐temporal evolution of submarine canyons by quantifying the related basin depositional elements and providing an estimate of intra‐ versus extra‐basinal sediment budget. The margin developed from the Jurassic to Aptian as a carbonate escarpment. Followed by, an Albian‐aged wave‐dominated delta system that prograded to the palaeo‐shelf edge. This is the first major delivery of siliciclastic sediment into the basin during the evolution of the continental margin, with increased sediment input linked to exhumation events of the hinterland. Subaqueous channel systems (up to 320 m wide) meandered through the pro‐delta region reaching the palaeo‐shelf edge, where it is postulated they initiated early submarine canyonisation of the margin. The canyonisation was long‐lived (ca. 28 Myr) dissecting the inherited seascape topography. Thirteen submarine canyons can be mapped, associated with a Late Cretaceous‐aged regional composite unconformity (RCU), classified as shelf incised or slope confined. Major knickpoints within the canyons and the sharp inflection point along the margin are controlled by the lithological contrast between carbonate and siliciclastic subcrop lithologies. Analysis of the base‐of‐slope deposits at the terminus of the canyons identifies two end‐member lobe styles, debris‐rich and debris‐poor, reflecting the amount of carbonate detritus eroded and redeposited from the escarpment margin (blocks up to ca. 1 km3). The vast majority of canyon‐derived sediment (97%) in the base‐of‐slope is interpreted as locally derived intra‐basinal material. The average volume of sediment bypassed through shelf‐incised canyons is an order of magnitude higher than the slope‐confined systems. These results document a complex mixed‐margin evolution, with seascape evolution, sedimentation style and volume controlled by shelf‐margin collapse, far‐field tectonic activity and the effects of hinterland rejuvenation of the siliciclastic source.

Study of magnetic relaxation, memory and rejuvenation effects in the cluster spin-glass phase of B-site disordered Ca(Fe1/2Nb1/2)O3 perovskite: Experimental evidence for hierarchical model

We explore the characteristics of the spin-glass phase of the lead-free complex perovskite Ca(Fe1/2Nb1/2)O3 (CFN) below the spin-glass transition temperature TSG ~24 K. The temperature dependence of the coercive field (Hc) and remanent magnetization (Mr) follow exponential behaviour as expected for the glassy phase. Detailed magnetic relaxation measurements as a function of time (t) with temperature (T) cycling on zero-field cooled (ZFC) and field cooled (FC) samples reveal that the cluster spin-glass phase of CFN exhibits a very slow non-exponential decay of thermoremanent magnetization with time as well as memory and rejuvenation effects. Our results demonstrate that the observed memory and rejuvenation effects in the cluster spin-glass phase of CFN can be explained by hierarchical model only and not by the droplet model.

Human embryonic stem cell-derived exosomes promote pressure ulcer healing in aged mice by rejuvenating senescent endothelial cells

Background & Aim Background:Angiogenesis, as an important endogenous repair mechanism, plays crucial roles in wound healing and tissue regeneration. However, this process is impaired in the elderly due to aging-related vascular endothelial dysfunction. This study was aimed to explore the pro-angiogenic effects of exosomes from human embryonic stem cells (ESC-Exos) in aged mice of pressure-induced ulcer model and the underlying mechanism. Methods, Results & Conclusion Methods: Pressure ulcer wounds were created on the back of D-galactose-induced aging mice. ESC-Exos were locally applied onto the wound beds, with PBS as control. The effects of ESC-Exos on wound healing were analyzed by measuring wound closure rates, histological and immunofluorescence analyses.The anti-aging effect of ESC-Exos on vascular endothelial cells was tested in an in vitro D-galactose-induced HUVEC senescence model. Results ESC-Exos could accelerate wound closure, enhance angiogenesis,and ameliorate the senescence of vascular endothelial cells significantly. ESC-Exos could rejuvenate the senescence of endothelial cells and recover compromised proliferation, migratory capacity, and tube formation in vitro. This recovery was Nrf2-activation-dependent, since cotreatment with Nrf2 inhibitor Brusatol could abolish the rejuvenative effects of ESC-Exos. Further study revealed that miR-200a was highly enriched in ESC-Exos and played a crucial role in ESC-Exos-mediated rejuvenation through downregulating Keap1, which negatively regulated Nrf2 expression. Conclusions ESC-Exos ameliorate endothelial senescence by activating Nrf2 and recover aging-related angiogenic dysfunction, thereby accelerate wound healing in aged mice. ESC-Exos might be a useful and natural nano-biomaterial for aging-related diseases therapy.