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BackgroundPeripheral vascular disease remains a leading cause of vascular morbidity and mortality worldwide despite advances in medical and surgical therapy. Besides traditional approaches, which can only restore blood flow to native arteries, an alternative approach is to enhance the growth of new vessels, thereby facilitating the physiological response to ischemia.MethodsThe ActinCreER/R26VT2/GK3 Rainbow reporter mouse was used for unbiased in vivo survey of injury-responsive vasculogenic clonal formation. Prospective isolation and transplantation were used to determine vessel-forming capacity of different populations. Single-cell RNA-sequencing was used to characterize distinct vessel-forming populations and their interactions.ResultsTwo populations of distinct vascular stem/progenitor cells (VSPCs) were identified from adipose-derived mesenchymal stromal cells: VSPC1 is CD45-Ter119-Tie2+PDGFRa-CD31+CD105highSca1low, which gives rise to stunted vessels (incomplete tubular structures) in a transplant setting, and VSPC2 which is CD45-Ter119-Tie2+PDGFRa+CD31-CD105lowSca1high and forms stunted vessels and fat. Interestingly, cotransplantation of VSPC1 and VSPC2 is required to form functional vessels that improve perfusion in the mouse hindlimb ischemia model. Similarly, VSPC1 and VSPC2 populations isolated from human adipose tissue could rescue the ischemic condition in mice.ConclusionsThese findings suggest that autologous cotransplantation of synergistic VSPCs from nonessential adipose tissue can promote neovascularization and represents a promising treatment for ischemic disease.

This thesis focuses on understanding the role of moiré patterns formed between graphene and metal substrate in governing the interfacial frictional behavior. The frictional system consists of graphene supported on a bulk copper substrate, which is investigated by atomistic simulations. The thesis first discusses moiré patterns appearing between graphene and copper, whose morphology depends on crystallographic orientation and relative positions. Depending on system temperature and the contacting nature, two extreme friction phenomena, namely superlubricity and supersticky, have been found, both of which are mediated by moiré patterns. The superlubricity effect can be achieved by tuning the rotation angle of moiré patterns to high value. However, such a condition only happens in metastable states with high potential energy, which induces the graphene layer spontaneously incline to lower energy state with small rotation angles, causing the disappearance of superlubricity. It is found that introducing grain boundaries in graphene can stabilize the high-angle moiré patterns and therefore retain superlubricity. On the other hand, supersticky effect was found to occur at ultra-low temperatures, at which stable moiré pattern persists and raises the resistance to sliding. In the end, the thesis provides details on the developed mathematical models, which describe the rotation and translation process of hexagonal moiré patterns, simplifying the generation of moiré patterns due to graphene rotation and lateral sliding movement.

This thesis focuses on understanding the role of moiré patterns formed between graphene and metal substrate in governing the interfacial frictional behavior. The frictional system consists of graphene supported on a bulk copper substrate, which is investigated by atomistic simulations. The thesis first discusses moiré patterns appearing between graphene and copper, whose morphology depends on crystallographic orientation and relative positions. Depending on system temperature and the contacting nature, two extreme friction phenomena, namely superlubricity and supersticky, have been found, both of which are mediated by moiré patterns. The superlubricity effect can be achieved by tuning the rotation angle of moiré patterns to high value. However, such a condition only happens in metastable states with high potential energy, which induces the graphene layer spontaneously incline to lower energy state with small rotation angles, causing the disappearance of superlubricity. It is found that introducing grain boundaries in graphene can stabilize the high-angle moiré patterns and therefore retain superlubricity. On the other hand, supersticky effect was found to occur at ultra-low temperatures, at which stable moiré pattern persists and raises the resistance to sliding. In the end, the thesis provides details on the developed mathematical models, which describe the rotation and translation process of hexagonal moiré patterns, simplifying the generation of moiré patterns due to graphene rotation and lateral sliding movement.

The taste of umami peptide H-Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala-OH (LGAGGSLA) is controversial. One possible reason for this controversy is the use of chemically synthesized LGAGGSLA to confirm its taste. To explore other ways to further confirm the flavor of LGAGGSLA, we developed a new strategy to prepare a bio-source peptide by adopting a gene engineering method to express LGAGGSLA in recombinant Escherichia coli. In our previous work, we structured the LGAGGSLA recombinant expression system and optimized the culturing conditions for preparing a fusion protein. However, the fusion protein was not cleaved by enterokinase to obtain LGAGGSLA. Because the cleavage conditions of commercial enterokinase were not specific and recombinant engineered bacteria had the potential to be used in industrial processes, in this addendum, we calculated the mass and volume yields of key processing steps in the preparation of LGAGGSLA, and established a model of cleavage conditions with the cleavage ratio of LGAGGSLA. When the LGAGGSLA was confirmed to show umami taste, it is considered as a new umami or umami enhancer. The gene information of LGAGGSLA should have a great potential in the development of new flavor product and food product containing high umami flavor.