A recent report from
the United Nations has warned about the excessive
CO2 emissions and the necessity of making efforts to keep
the increase in global temperature below 2 °C. Current CO2 capture technologies are inadequate for reaching that goal,
and effective mitigation strategies must be pursued. In this work,
we summarize trends in materials development for CO2 adsorption
with focus on recent studies. We put adsorbent materials into four
main groups: (I) carbon-based materials, (II) silica/alumina/zeolites,
(III) porous crystalline solids, and (IV) metal oxides. Trends in
computational investigations along with experimental findings are
covered to find promising candidates in light of practical challenges
imposed by process economics.
Massive rotator cuff tears (MRCTs) of the shoulder cause disability and pain among the adult population. In chronic injuries, the tendon retraction and subsequently the loss of mechanical load lead to muscle atrophy, fat accumulation, and fibrosis formation over time. The intrinsic repair mechanism of muscle and the successful repair of the torn tendon cannot reverse the muscle degeneration following MRCTs. To address these limitations, we developed an electroconductive matrix by incorporating graphene nanoplatelets (GnPs) into aligned poly(l-lactic acid) (PLLA) nanofibers. This study aimed to understand 1) the effects of GnP matrices on muscle regeneration and inhibition of fat formation in vitro and 2) the ability of GnP matrices to reverse muscle degenerative changes in vivo following an MRCT. The GnP matrix significantly increased myotube formation, which can be attributed to enhanced intracellular calcium ions in myoblasts. Moreover, the GnP matrix suppressed adipogenesis in adipose-derived stem cells. These results supported the clinical effects of the GnP matrix on reducing fat accumulation and muscle atrophy. The histological evaluation showed the potential of the GnP matrix to reverse muscle atrophy, fat accumulation, and fibrosis in both supraspinatus and infraspinatus muscles at 24 and 32 wk after the chronic MRCTs of the rat shoulder. The pathological evaluation of internal organs confirmed the long-term biocompatibility of the GnP matrix. We found that reversing muscle degenerative changes improved the morphology and tensile properties of the tendon compared with current surgical techniques. The long-term biocompatibility and the ability of the GnP matrix to treat muscle degeneration are promising for the realization of MRCT healing and regeneration.
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