The nasal septal cartilage plays an important role in preventing the collapse of the nasal bones and maintaining the appearance of the nose. In the context of inherent difficulties regarding septal ...cartilage repair and the shortage of cartilage graft resources for regeneration, tissue engineering, especially the in situ strategy based on scaffolds, has become a new prospect and become one of the most promising approaches. Given that it is difficult for chondrocytes to achieve directional migration and secrete matrix components to participate in tissue repair after cartilage injury, cartilage progenitor cells (CPCs), with great migratory ability and stem cell characteristics, have caught the attention of researchers and brought hope for nasal septal cartilage in situ regeneration. In this review, we first summarized the distribution, characteristics, isolation, and culture methods of nasal septal CPCs. Subsequently, we described the roles of migratory CPCs in cartilage regeneration. Finally, we reviewed the existing studies on CPCs-based cartilage tissue engineering and summarized the strategies for promoting the migration and chondrogenesis of CPCs so as to provide ideas for achieving nasal septal cartilage in situ regeneration.
The major troubles in 6-(
N
-hydroxyethyl)-amino-6-deoxy-
α
-
l
-sorbofuranose (6NSL) production from
N
-2-hydroxyethyl glucamine (NHEG) by
Gluconobacter oxydans
were low cell yield during cell ...preparation and loss of cells’ biocatalytic ability during biotransformation, resulting in high production cost and low 6NSL production. The target of this work was to enhance 6NSL production by reusing cells and improving the cells biocatalytic ability. First, inhibitory effects of substrate and product on 6NSL production, and optimization of cell regeneration condition were investigated, respectively. Then repeated production of 6NSL by immobilized cell using a strategy of in situ exhaustive cell regeneration in a bubble column bioreactor was developed. As a result, the bioprocess underwent nine cycles, the average 6NSL production and conversion rate of NHEG to 6NSL reached 42.6 g L
−1
and 83.1% in each batch was achieved, respectively.
The uptake of hexavalent chromium (Cr(VI)) ions from wastewater is of great significance for environmental remediation and resource utilization. In this study, a self‐designed instrument equipped ...with an oxidized mesoporous carbon monolith (o‐MCM) as an electro‐adsorbent is developed. o‐MCM with a super hydrophilic surface displayed a high specific surface area (up to 686.5 m2 g−1). With the assistance of an electric field (0.5 V), the removal capacity of Cr(VI) ions is as high as 126.6 mg g−1, much higher than that without an electric field (49.5 mg g−1). During this process, no reduction reaction of Cr(VI) to Cr(III) ions is observed. After adsorption, the reverse electrode with 10 V is used to efficiently desorb the ions on the carbon surface. Meanwhile, the in situ regeneration of carbon adsorbents can be obtained even after ten recycles. On this basis, the enrichment of Cr(VI) ions in a special solution is achieved with the assistance of an electric field. This work lays a foundation for the uptake of heavy metal ions from wastewater with the assistance of the electric field.
The efficient uptake of Cr(VI) ions from wastewater with the assistance of an electric field is achieved by using a self‐designed instrument equipped with an oxidized mesoporous carbon monolith as an electro‐adsorbent. The in situ regeneration of carbon adsorbents and the enrichment of Cr(VI) ions in a special solution is obtained with the assistance of an electric field.
Atmospheric-pressure air plasma, powered by alternating current (AC) sine-wave high voltage, can in-situ regenerate deactivated Au nanocatalysts during CO oxidation, but it needs high-humidity air as ...the discharge gas. To overcome the limitation on humidity for in-situ regeneration of air plasma, a square-wave pulsed plasma is applied in this work. Differently from the AC plasma, the pulsed plasma exhibits excellent regeneration performance at any humidity. Further, surface carbonate decomposition, nitrogen oxides poisoning species and electric discharge of the pulsed plasma regeneration are investigated. For the pulsed plasma regeneration at any humidity, the evolution of CO
2
concentration with the regeneration time almost keeps the same profile, featuring zero-order kinetics for the carbonate decomposition; on the other hand, whether in the gas phase or on the catalyst surface, there are no formation of poisoning nitrogen oxides. The pulsed plasma at any humidity has the powerful ability in carbonate decomposition and simultaneously prevents the formation of poisoning nitrogen oxides, which is ascribed to its highly centralized energy deposition with high instantaneous power and long interval of instantaneous power. For practical application, normal air is also confirmed to be qualified for the pulsed plasma regeneration.
Ecological ditches and zeolite have been widely applied in the removal of farmland nonpoint source pollution separately; little research has been done on the effects of combining the two methods. ...Specifically, few studies have focused on the in situ regeneration of zeolite. A 2-year field experiment using an ecological ditch–zeolite barrier system was conducted in a paddy field of summer rice–winter wheat rotation in the Taihu Lake area. The system consisted of two zeolite barriers positioned at one third and two thirds of the length of the ditch. This study focused on the effect of the system on in situ nitrogen removal during the rice-growing season. Simultaneous laboratory kinetics experiments with natural zeolite and a series of adsorbed zeolites taken from the ditch at different time were also conducted. The concentration removal efficiencies of total nitrogen are averaged 24.66% in 2014 and 30.39% in 2015. Meanwhile, the cumulative adsorption quantity of ammonia nitrogen by the two barriers accounted for 49.27% of the ammonia nitrogen removed in 2014 and 54.35% of that in 2015. The amount of nitrogen adsorbed by plants was larger than that adsorbed by zeolite. The breakthrough curves of the zeolite and the characteristics of the zeolite surface structures from different periods all demonstrated that the zeolite can be regenerated in situ in the case of unsaturated zeolite within the ecological ditch. It can be concluded that an ecological ditch–zeolite barrier system is a realistic option for removing nitrogen from agricultural rainfall runoff in the Taihu Lake area.
Local delivery of growth factors (GFs) can accelerate regeneration of injured tissue, but for many medical applications, injectable GF delivery systems are required for clinical success. ...Viscoelastic, injectable aggregates of micrometer-sized hydrogel particles made of multiarmed polyethylene glycol (starPEG) and heparin were prepared and tested for site-specific paracrine stimulation of tissue regeneration. Heparin was used as it binds, protects and releases numerous GFs. Hydrogel based delivery of basic fibroblast growth factor (bFGF) and murine epidermal growth factor (EGF) was monitored utilizing enzyme-linked immunosorbent assay (ELISA). bFGF was released slowly because of its high affinity to the heparin while the significantly higher release of the non-specific binding EGF was controlled by diffusion only. To investigate GF delivery in vivo, a hydrogel loaded with murine EGF or bFGF was injected subcapsularly into the left kidney of mice with experimental acute kidney injury caused by glycerol induced rhabdomyolysis. Visual examination confirmed sustained stability of the injected gel aggregates during the timescale of the experiment. The number of proliferating kidney tubular epithelial cells was quantified both in the injected kidney and the non-injected contralateral kidney. bFGF delivery from hydrogels induced a significant increase in cell proliferation in the injected kidney, although small effects were also seen in the non-injected kidney due to a systemic effect. EGF delivery strongly increased cell proliferation for both kidneys, but also showed a local effect on the injected kidney. The hydrogel without loaded GFs was used as a control and showed no increase in cell proliferation. Our results suggest that this novel starPEG-heparin hydrogel system can be an effective approach to deliver GFs locally.
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Highlights • Discusses the different repair mechanisms involved in wound healing of fibroblast at different developmental stages. • Further expounded the different outcomes of wound repair in using ...adult and fetal fibroblasts in a clinical siting. • Describe the current problems associated with the use of fetal fibroblasts in skin repair. • Further prospects regarding the use of small molecules to improve the regenerative capacity of host cells in the wound as a more innovative and practical implementation for skin regeneration.
Granular activated carbon (GAC) can remove trace organic pollutants and natural organic matter (NOM) from industrial and municipal waters. This paper evaluates an iron nanocatalyst approach, based on ...Fenton-like oxidation reactions, to regenerate spent GAC within a packed bed configuration after saturation by organic compounds. Specifically, we focus on regenerating GAC packed beds equilibrated with varying influent concentrations of phenol, a model organic compound. Iron nanocatalysts were synthesized using ferric chloride, a chemical already used as a coagulant at municipal WTPs, and reacted with hydrogen peroxide (H2O2) for the purpose of in-situ regeneration. Up to 95% of phenol adsorption capacity was regenerated for GAC equilibrated with 1000 mg/L of phenol. Using this technique, at least four adsorption–regeneration cycles can be performed sequentially for the same batch of GAC with fresh iron nanocatalysts while achieving a regeneration efficiency of 90 ± 5% between each loading. Moreover, the iron nanocatalyst can be recovered and reused multiple times. Lower initial adsorbate concentrations (10–500 mg/L) resulted in a slightly lower saturated adsorbent-phase concentration of phenol and lower regeneration efficiencies (72 ± 5%). Additionally, this catalytic in-situ regeneration was applied to GAC saturated by NOM. A slightly lower regeneration efficiency (60%) was observed for the Suwannee River NOM adsorption capacity of GAC. The next step is validation in a pilot-scale test that applies this regeneration technique to a GAC adsorber employed in NOM removal.
► We perform in-situ regeneration of phenol-saturated GAC using iron nanocatalyst/H2O2. ► 90% Regeneration efficiency is achieved when GAC is saturated by 1000 mg-phenol/L. ► Five adsorption–regeneration cycles can be conducted on the same batch of GAC. ► Regeneration efficiency decreases if the initial adsorbate concentration is lower. ► The used iron nanocatalyst can be recycled without significant loss of reactivity.
Catalyst lifetime represents one of the most crucial economic aspects in industrial catalytic processes, due to costly shutdowns, catalyst replacements, and proper disposal of spent materials. Not ...surprisingly, there is considerable motivation to understand and treat catalyst deactivation, poisoning, and regeneration, which causes this research topic to continue to grow. The complexity of catalyst poisoning obviously increases along with the increasing use of biomass/waste-derived/residual feedstocks and with requirements for cleaner and novel sustainable processes. This book collects 15 research papers providing insights into several scientific and technical aspects of catalyst poisoning and deactivation, proposing more tolerant catalyst formulations, and exploring possible regeneration strategies.
Chemical modulation of cell fates has been widely used to promote tissue and organ regeneration. Small molecules can target the self-renewal, expansion, differentiation, and survival of endogenous ...stem cells for enhancing their regenerative power or induce dedifferentiation or transdifferentiation of mature cells into proliferative progenitors or specialized cell types needed for regeneration. Here, we discuss current progress and potential using small molecules to promote in vivo regenerative processes by regulating the cell fate. Current studies of small molecules in regeneration will provide insights into developing safe and efficient chemical approaches for in situ tissue repair and regeneration.
