Regulation of MRI contrast and cellular retention time by cellular interfacial distribution of Gd agents:Implications for stem cell tracking

Human mesenchymal stem cells(hMSCs)were labeled with Dotarem or(Gd-DOTA)2-EM7(EM7Gd2)via electroporation(EP).Cellular transmission electron microscopy(TEM)reveals free distribution of Gd agents and formation of EM7Gd2 clusters in the cytosol.Cellular magnetic resonance imaging(MRI)reveals that the free Gd agents induce MRI signal enhancement effect due to its fast exocytosis and subsequent interaction with intercellular water molecules.The EM7Gd2 clusters exhibits a longer intracellular retention time and induce a persistent MRI signal reduction effect.The cellular MRI results are interpreted by taking into account both T1 and T2 relaxation rates and their correlation with cellular binding structures of Dotarem and EM7Gd2.

Imaging cellular distribution of fluorescent supramolecular nanofibers

In this study, we used the 4-nitro-2,1,3-benzoxadiazole （NBD） as an aromatic capping group for a peptide to construct the su- pramolecular nanofibers. Taking the advantage of the fluorescence property of NBD, we could directly observe the cellular distribution of the self-assembled nanofibers. We found that the distributions of the nanofibers of NBD-FFETIGGY are dif- ferent in four mammalian cells and two plant cells. The nanofibers are mainly located at the surface of two mammalian cells and one plant cell, while in the intracellular space of other cells. Different distributions of nanofibers lead to different protein binding patterns o1! the nanofibers in two different cell lines. We believe that a useful and versatile platform has been offered to the image cellular distribution of nanofibers, which can provide useful information to the biological functions of the self-assembled nanostructures.

Size and spatial distribution of landslides induced by the2015 Gorkha earthquake in the Bhote Koshi river watershed

The Mw 7.8 Gorkha earthquake in Nepal on April 25, 2015, produced thousands of landslides in the Himalayan mountain range. After the earthquake, two field investigations along Araniko Highway were conducted. Then, using remote sensing technology and geographic information system(GIS)technology, 1481 landslides were identified along the Bhote Koshi river. Correlations between the spatial distribution of landslides with slope gradient and lithology were analyzed. The power-law relationship of the size distribution of earthquake-induced landslides was examined in both the Higher Himalaya and Lesser Himalaya. Possible reasons for the variability of the power exponent were explored by examining differences in the geological situations of these areas. Multi-threshold cellular automata were introduced to model the complexity of system components. Most of the landslides occurred at slope gradients of 30°–40°, and the landslide density was positively correlated with slope gradient. Landslides in hard rock areas were more common than in soft rock areas. The cumulative number-area distribution of landslides induced by the Gorkha earthquake exhibited a negative power-law relationship, but the power exponents were different: 1.13 in the Higher Himalaya, 1.36 and Lesser Himalaya. Furthermore,the geological conditions were more complex and varied in the Lesser Himalaya than in the Higher Himalaya, and the cellular automata simulation results indicated that, as the complexity of system components increased, the power exponent increased.Therefore, the variability of the power exponent of landslide size distribution should ascribe to the complexity of geological situations in the Bhote Koshi river watershed.

Subcellular localization of PS1 based on PS1/GFP fusing protein

Mutations in presenilin 1(PS1)gene are closely associated with the early onset of familial Alzheimer’s disease(EOFAD).The fusion genes,GFP-PS1(recombinant plasmid pEGFP-C1-PS1)and PS1-GFP(recombinant plasmid pEGFP-N2-PS1)were constructed to study the subcellular localization of PS1 holoprotein.Recombinant plasmids were transiently transfected into two cell lines,HEK293 and CHO,respectively,using the green fluorescence from GFP(green fluorescence protein)as the PS1 localization signal.Then,we observed green fluorescence with a SPOT II(Olympus,BH2)and CONFOCAL microscope(Olympus,FV300)under 488 nm.The results show that PS1 located on the nuclear envelope.A few can be found on the cellular membrane and in the cytosol in a non-homogeneous distribution.

Elastic Fiber‑Reinforced Silk Fibroin Scaffold with A Double‑Crosslinking Network for Human Ear‑Shaped Cartilage Regeneration

Tissue engineering provides a promising approach for regenerative medicine.The ideal engineered tissue should have the desired structure and functional properties suitable for uniform cell distribution and stable shape fidelity in the full period of in vitro culture and in vivo implantation.However,due to insufficient cell infiltration and inadequate mechanical properties,engineered tissue made from porous scaffolds may have an inconsistent cellular composition and a poor shape retainability,which seriously hinders their further clinical application.In this study,silk fibroin was integrated with silk short fibers with a physical and chemical double-crosslinking network to fabricate fiber-reinforced silk fibroin super elastic absorbent sponges(Fr-SF-SEAs).The Fr-SF-SEAs exhibited the desirable synergistic properties of a honeycomb structure,hygroscopicity and elasticity,which allowed them to undergo an unconventional cyclic compression inoculation method to significantly promote cell diffusion and achieve a uniform cell distribution at a high-density.Furthermore,the regenerated cartilage of the Fr-SF-SEAs scaffold withstood a dynamic pressure environment after subcutaneous implantation and maintained its precise original structure,ultimately achieving human-scale ear-shaped cartilage regeneration.Importantly,the SF-SEAs prepara-tion showed valuable universality in combining chemicals with other bioactive materials or drugs with reactive groups to construct microenvironment bionic scaffolds.The established novel cell inoculation method is highly versatile and can be readily applied to various cells.Based on the design concept of dual-network Fr-SF-SEAs scaffolds,homogenous and mature cartilage was successfully regenerated with precise and complicated shapes,which hopefully provides a platform strategy for tissue engineering for various cartilage defect repairs.