In this work, an electric field-enhanced heterogeneous catalytic ozonation (EHCO) was systematically investigated using a prepared FeOx/PAC catalyst. The EHCO process exhibited high sulfadiazine ...(SDZ) and TOC removal efficiency compared with electrocatalysis (EC) and heterogeneous catalytic ozonation (HCO) process. Almost 100% of SDZ was removed within 2 min, and the TOC removal reached approximately 85% within 60 min. Quenching experiments and EPR analysis suggested that the prominent SDZ and TOC removal performance is supported by the enhanced ·OH generation ability. Further study proved that H2O2 formed by O2 electrochemical reduction, peroxone reaction and electrochemical reduction of ozone contributed to improving ·OH generation. Furthermore, the EHCO system showed satisfactory stability and recyclability compared to conventional HCO systems, and the SDZ and TOC removal rates were maintained at ≥95% and ≥70% in 16 consecutive recycles, respectively. Meanwhile, XPS analysis and Boehm's titration for the FeOx/PAC catalyst used in HCO and EHCO process confirmed that the external electron supply could restrain the oxidation of surface functional groups of PAC and maintain a balance of the Fe(II)/Fe(III) ratio, which proved the critical role of cathode reduction in catalyst in situ regeneration during long consecutive recycles. In addition, the EHCO system could achieve more than 80% SDZ removal within 2 min in different water matrices. These results confirmed that the EHCO process has a wide application perspective for refractory organics removal in actual wastewater.
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•An electric field-enhanced heterogeneous catalytic ozonation (EHCO) was developed.•Sulfadiazine removal and mineralization efficiency reached almost 100% and 85% by EHCO process.•FeOx/PAC heterogeneous catalyst could be in situ regenerated by cathodic reduction.•A feasible application achieved for antibiotics removal in actual water.
Reactive dyeing of cotton generates a great deal of coloring wastewater containing residual dyes, electrolyte, alkali, and other auxiliaries. Especially for the effluent from the first/initial spent ...dyeing bath, it may be comprised of as high as 60% of the initial dye dosed, 30–90 g/L of sodium chloride or sodium sulfate, and plenty of sodium carbonate, making it to be the most contaminative effluent among the entire reactive dyeing process. This paper presents a new alternative to regenerate the waste effluent from the first spent dyeing bath through catalytic ozonation with novel catalysts for reuse of the effluent in successive dyeing. Two novel ozonation catalysts, mesoporous carbon aerogel and its supported cobalt oxide nanoparticles, were successfully prepared and used in catalytic degradation of residual dyes in waste effluents with ozone. Degradation efficiency was determined by both decolorization and chemical oxygen demand removal. The result showed novel catalysts could improve both of these two targets. For chemical oxygen demand removal, carbon aerogel supported cobalt oxide strikingly enhanced the efficiency by 30% on the whole comparing to ozonation alone (approximately 50%) without the catalyst. Waste effluents after catalytic ozonation were thereafter reused in successive dyeing in the same process. It has been validated that the waste effluent was successfully regenerated and can be additionally reused twice without sacrificing fabric quality, which cannot be realized in ozonation alone. Color difference of the fabric dyed with the regenerated effluent was within the acceptable tolerance, and excellent levelness and equal colorfastness had also been achieved. This is probably the first study to investigate the feasibility of regenerating highly polluting dyeing effluents for reuse by catalytic ozonation with carbon aerogel materials. With novel catalysts, it could be speculated that catalytic ozonation is a promising technology for in-situ regeneration of waste effluents in textile dyeing plant for reuse.
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•Mesoporous carbon aerogel catalysts have been prepared for catalytic ozonation.•Dye degradation efficiency was strikingly improved by ozonation with the catalyst.•Regeneration of highly polluting effluents was realized by catalytic ozonation.•The regenerated effluent can be reused in textile dyeing without quality defection.
Hirschsprung disease (HSCR) is a life-threatening birth defect in which the distal colon is devoid of enteric neural ganglia. HSCR is treated by surgical removal of aganglionic bowel, but many ...children continue to have severe problems after surgery. We studied whether administration of glial cell derived neurotrophic factor (GDNF) induces enteric nervous system regeneration in mouse models of HSCR.
We performed studies with four mouse models of HSCR: Holstein (HolTg/Tg, a model for trisomy 21-associated HSCR), TashT (TashTTg/Tg, a model for male-biased HSCR), Piebald-lethal (Ednrbs-l//s-l, a model for EDNRB mutation-associated HSCR), and Ret9/− (with aganglionosis induced by mycophenolate). Mice were given rectal enemas containing GDNF or saline (control) from postnatal days 4 through 8. We measured survival times of mice, and colon tissues were analyzed by histology, immunofluorescence, and immunoblots. Neural ganglia regeneration and structure, bowel motility, epithelial permeability, muscle thickness, and neutrophil infiltration were studied in colon tissues and in mice. Stool samples were collected, and microbiomes were analyzed by 16S rRNA gene sequencing. Time-lapse imaging and genetic cell-lineage tracing were used to identify a source of GDNF-targeted neural progenitors. Human aganglionic colon explants from children with HSCR were cultured with GDNF and evaluated for neurogenesis.
GDNF significantly prolonged mean survival times of HolTg/Tg mice, Ednrbs-l//s-l mice, and male TashTTg/Tg mice, compared with control mice, but not Ret9/− mice (which had mycophenolate toxicity). Mice given GDNF developed neurons and glia in distal bowel tissues that were aganglionic in control mice, had a significant increase in colon motility, and had significant decreases in epithelial permeability, muscle thickness, and neutrophil density. We observed dysbiosis in fecal samples from HolTg/Tg mice compared with feces from wild-type mice; fecal microbiomes of mice given GDNF were similar to those of wild-type mice except for Bacteroides. Exogenous luminal GDNF penetrated aganglionic colon epithelium of HolTg/Tg mice, inducing production of endogenous GDNF, and new enteric neurons and glia appeared to arise from Schwann cells within extrinsic nerves. GDNF application to cultured explants of human aganglionic bowel induced proliferation of Schwann cells and formation of new neurons.
GDNF prolonged survival, induced enteric neurogenesis, and improved colon structure and function in 3 mouse models of HSCR. Application of GDNF to cultured explants of aganglionic bowel from children with HSCR induced proliferation of Schwann cells and formation of new neurons. GDNF might be developed for treatment of HSCR.
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Ischemic diseases lead to considerable morbidity and mortality, yet conventional clinical treatment strategies for therapeutic angiogenesis fall short of being impactful. Despite the potential of ...biomaterials to deliver pro-angiogenic molecules at the infarct site to induce angiogenesis, their efficacy has been impeded by aberrant vascular activation and off-target circulation. Here, we present a semisynthetic low-molecular sulfated chitosan oligosaccharide (SCOS) that efficiently induces therapeutic arteriogenesis with a spontaneous generation of collateral circulation and blood reperfusion in rodent models of hind limb ischemia and myocardial infarction. SCOS elicits anti-inflammatory macrophages' (Mφs') differentiation into perivascular Mφs, which in turn directs artery formation via a cell-to-cell communication rather than secretory factor regulation. SCOS-mediated arteriogenesis requires a canonical Notch signaling pathway in Mφs via the glycosylation of protein O-glucosyltransferases 2, which results in promoting arterial differentiation and tissue repair in ischemia. Thus, this highly bioactive oligosaccharide can be harnessed to direct efficiently therapeutic arteriogenesis and perfusion for the treatment of ischemic diseases.
Objective
Hyaluronic acid–transglutaminase (HA-TG) is an enzymatically crosslinkable adhesive hydrogel with chondrogenic properties demonstrated in vitro and in an ectopic mouse model. In this study, ...we investigated the feasibility of using HA-TG in a collagen scaffold to treat chondral lesions in an ovine model, to evaluate cartilage regeneration in a mechanically and biologically challenging joint environment, and the influence of the surgical procedure on the repair process.
Design
Chondral defects of 6-mm diameter were created in the stifle joint of skeletally mature sheep. In a 3-month study, 6 defects were treated with HA-TG in a collagen scaffold to test the stability and biocompatibility of the defect filling. In a 6-month study, 6 sheep had 12 defects treated with HA-TG and collagen and 2 sheep had 4 untreated defects. Histologically observed quality of repair tissue and adjacent cartilage was semiquantitatively assessed.
Results
HA-TG adhered to the native tissue and did not cause any detectable negative reaction in the surrounding tissue. HA-TG in a collagen scaffold supported infiltration and chondrogenic differentiation of mesenchymal cells, which migrated from the subchondral bone through the calcified cartilage layer. Additionally, HA-TG and collagen treatment led to better adjacent cartilage preservation compared with empty defects (P < 0.05).
Conclusions
This study demonstrates that the adhesive HA-TG hydrogel in a collagen scaffold shows good biocompatibility, supports in situ cartilage regeneration and preserves the surrounding cartilage. This proof-of-concept study shows the potential of this approach, which should be further considered in the treatment of cartilage lesions using a single-step procedure.
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•In-situ regeneration of GAC using electric potential swing desorption (EPSD).•Desorption was 3 times faster with EPSD compared with a non-potential system.•Accessible H2S adsorption ...sites were regenerated using EPSD system.
In-situ regeneration of a granular activated carbon was conducted for the first time using electric potential swing desorption (EPSD) with potentials up to 30 V. The EPSD system was compared against a standard non-potential system using a fixed-bed reactor with a bed of 10 g of activated carbon treating a gas mixture with 10,000 ppm H2S. Breakthrough times, adsorption desorption volume, capacities, effect of regeneration and desorption kinetics were investigated. The analysis showed that desorption of H2S using the new EPSD system was 3 times quicker compared with the no potential system. Hence, physical adsorption using EPSD over activated carbon is efficient, safe and environmental friendly and could be used for the in-situ regeneration of granular activated carbon without using a PSA and/or TSA system. Additionally, adsorption and desorption cycles can be obtained with a classical two column system, which could lead towards a more efficient and economic biogas to biomethane process.
The demands for efficient and robust heterogeneous hydrogenation catalysts have triggered extensive research to optimize the structures of metal catalytic centers, but the potential of support ...construction for enhanced hydrogenation performance has been overlooked. This study introduces a hierarchically ordered porous poly(2,6‐diaminopyridine) (PDAP) as a Pd nanoparticle support for hydrogenation removal of recalcitrant pollutants in water purification. The PDAP support acts as a sorbent and microreactor to enhance the proximity of targeted water pollutants and reactive hydrogen atom species, achieving unprecedently high water purification efficiency. The PDAP support also acts as a catalyst in mediating peroxide‐activation for oxidative destruction of Pd poisons (e.g., reduced sulfur), achieving in situ regeneration of poisoned Pd catalysis centers. The high activity and in situ regenerativity achieved by rational construction of the support structure sheds light on a new approach for designing efficient and robust heterogeneous hydrogenation catalysts.
This study introduces hierarchically ordered porous poly(2,6‐diaminopyridine) (PDAP) as a Pd nanoparticle support for hydrogenation removal of recalcitrant pollutants during water purification. The PDAP support acts as a sorbent and microreactor to enhance the proximity of targeted water pollutants and reactive hydrogen atom species. The PDAP support also acts as a catalyst in mediating peroxide activation for oxidative destruction of Pd poisons.
The performance of a commercial NH3-SCR catalyst used for 20,000 h in a 660 MW coal fired power plant was evaluated after treated in situ with water vapor at 300–350 °C for 336 h. The conversion of ...NOx reached 91.4% after this water treatment. The recovery of catalytic activity is mainly due to the removal of potassium, arsenic and sulfate-containing deposits from the catalyst surface, as well as the increase of surface active oxygen species and specific surface area. These results indicate that commercial NH3-SCR catalysts are deactivated by the deposition of water-soluble substances and which can be in situ regenerated cost-effectively with high-temperature water vapor treatment.
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•High-temperature water vapor can regenerate commercial SCR catalysts in-situ.•High-temperature water vapor eliminates contaminants deposited on SCR catalysts.•Water vapor improves reducibility and active oxygen states of SCR catalysts.
Copper (Cu) is an attractive low‐cost alternative to silver or gold. However, it is susceptible to oxidation in air. Here, facile in situ regeneration of oxidized Cu flakes (CuFLs) for the synthesis ...of highly conductive non‐oxidized nanocomposites is reported. The oxidized CuFLs are regenerated into non‐oxidized CuFLs and Cu nanosatellite (CuNS) particles by formic acid‐aided in situ etching and reduction reaction in soft epoxy matrix. The average particle size of CuNS particles is only 3.3 nm with an interparticle distance of 2.7 nm. Furthermore, the negligible potential barrier height between Cu and epoxy dramatically increases the electrical conductivity (66 893 S cm−1) of the nanocomposite (Cu = 46 vol%) by more than three orders of magnitude. The thermal conductivity is also highest (85.1 W m−1 K−1), compared with Cu‐based nanocomposites in literature. The conductivities are invariant in air for more than 95 days. The simple scalable in situ regeneration of oxidized CuFLs may find immediate industrial applications.
Oxidized copper flakes (CuFLs) are regenerated into non‐oxidized CuFLs and nanosatellite particles (3.3 nm) by formic acid‐aided in situ etching and reduction in epoxy . The negligible potential barrier between copper and epoxy dramatically increases air‐stable electrical conductivity (66 893 S cm−1) by more than three orders of magnitude. Thermal conductivity is also highest (85.1 W m−1 K−1) for copper‐based nanocomposites.
Resident stem cell pools in many tissues/organs are responsible not only for tissue maintenance during physiologic turnover but also for the process of wound repair following injury. With inspiration ...from stem cell trafficking within the body under physiologic and pathologic conditions, recent advances have been made toward inducing stem cell mobilization and directing patients’ own cells to sites of interest for treating a broad spectrum of diseases. An evolving body of work corroborates that delivering guidance cues can mobilize stem cells from the bone marrow and drive these cells toward a specific region. In addition, the transplantation of cell-friendly biomaterials incorporating certain biomolecules has led to the regeneration of lost/damaged tissue without the need for delivering cellular materials manipulated ex vivo. Recently, cell homing has resulted in remarkable biological discoveries in the laboratory as well as great curative successes in preclinical scenarios. Here, we review the biological evidence underlying in vivo cell mobilization and homing with the aim of leveraging endogenous reparative cells for therapeutic applications. Considering both the promise and the obstacles of this approach, we discuss how matrix components of the in vivo milieu can be modified to promote the native regenerative process and inspire future tissue-engineering design.
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