ORCID Profile
0000-0002-4095-7435
Current Organisations
Institute of Tibetan Plateau Research Chinese Academy of Sciences
,
Houston Methodist Research Insistute
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Publisher: American Chemical Society (ACS)
Date: 28-12-2010
DOI: 10.1021/NN102461W
Abstract: The destruction and hollowing of entire tissue segments represent an insurmountable barrier to axonal regeneration and therapeutics in chronic spinal cord injury. To circumvent this problem, we engineered neural prosthetics, by assembling electrospun nanofibers and self-assembling peptides into composite guidance channels and transplanted them into the cysts of a postcontusive, chronic spinal cord injury rat model, also providing delivery of proregenerative cytokines. Six months later conspicuous cord reconstruction was observed. The cyst was replaced by newly formed tissue comprising neural and stromal cells. Nerve fibers were interspersed between and inside the guidance channels, spanning the lesion, amidst a well-developed vascular network, basal lamina, and myelin. This was accompanied by a significant improvement in the activity of ascending and descending motor pathways and the global locomotion score. Thus by engineering nanostructured matrices into neuroprosthetics, it is possible to recreate an anatomical, structural, and histological framework, which leads to the replacement of large, hollow tissue gaps in the chronically injured spinal cord, fostering axonal regeneration and neurological recovery.
Publisher: American Chemical Society (ACS)
Date: 11-02-2011
DOI: 10.1021/NN102663A
Abstract: Self-assembling peptides (SAPs) are rapidly gaining interest as bioinspired scaffolds for cell culture and regenerative medicine applications. Bone Marrow Homing Peptide 1 (BMHP1) functional motif (PFSSTKT) was previously demonstrated to stimulate neural stem cell (NSC) viability and differentiation when linked to SAPs. We here describe a novel ensemble of SAPs, developed from the BMHP1 (BMHP1-SAPs), that spontaneously assemble into tabular fibers, twisted ribbons, tubes and hierarchical self-assembled sheets: organized structures in the nano- and microscale. Thirty-two sequences were designed and evaluated, including biotinylated and unbiotinylated sequences, as well as a hybrid peptide-peptoid sequence. Via X-ray diffraction (XRD), CD, and FTIR experiments we demonstrated that all of the BMHP1-SAPs share similarly organized secondary structures, that is, β-sheets and β-turns, despite their heterogeneous nanostructure morphology, scaffold stiffness, and effect over NSC differentiation and survival. Notably, we demonstrated the self-healing propensity of most of the tested BMHP1-SAPs, enlarging the set of potential applications of these novel SAPs. In in vitro cell culture experiments, we showed that some of these 10-mer peptides foster adhesion, differentiation, and proliferation of human NSCs. RGD-functionalized and hybrid peptide-peptoid self-assembling sequences also opened the door to BMHP1-SAP functionalization with further bioactive motifs, essential to tailor new scaffolds for specific applications. In in vivo experiments we verified a negligible reaction of the host nervous tissue to the injected and assembled BMHP1-SAP. This work will pave the way to the development of novel SAP sequences that may be useful for material science and regenerative medicine applications.
Publisher: Springer Science and Business Media LLC
Date: 28-07-2022
DOI: 10.1038/S41467-022-32172-9
Abstract: Stable isotope paleoaltimetry that reconstructs paleoelevation requires stable isotope (δD or δ 18 O) values to follow the altitude effect. Some studies found that the δD or δ 18 O values of surface isotopic carriers in some regions increase with increasing altitude, which is defined as an “inverse altitude effect” (IAE). The IAE directly contradicts the basic theory of stable isotope paleoaltimetry. However, the causes of the IAE remain unclear. Here, we explore the mechanisms of the IAE from an atmospheric circulation perspective using δD in water vapor on a global scale. We find that two processes cause the IAE: (1) the supply of moisture with higher isotopic values from distant source regions, and (2) intense lateral mixing between the lower and mid-troposphere along the moisture transport pathway. Therefore, we caution that the influences of those two processes need careful consideration for different mountain uplift stages before using stable isotope palaeoaltimetry.
Publisher: American Geophysical Union (AGU)
Date: 07-03-2023
DOI: 10.1029/2022GL102229
Abstract: Stable hydrogen isotopes in monsoonal precipitation (δD p ) at three sites (Port Blair, Barisal and Darjeeling) reveal the factors governing δD p variations over a south‐north gradient across the Bay of Bengal. We found that the δD p at each site continuously decreases from May to September and these trends become more pronounced from south to north. The decreasing trends of downstream δD p closely follow the decreasing trends of upstream stable hydrogen isotopes in water vapor (δD v ), which indicates that upstream δD v properties shape initial spatiotemporal patterns of the downstream δD p (“shaping effect”). Additionally, our results demonstrate that, during moisture transport, upstream vertical air motions (convection and downward motion) and topographic relief magnify the litude of the decreasing trends of downstream δD p (“magnifying effect”). Our findings imply that upstream δD v properties and relevant atmospheric and topographical conditions along the moisture transport pathway need to be considered collectively to better interpret paleoclimate records.
Location: China
Location: United States of America
No related grants have been discovered for 光剑 邬.