Weak extremely-low-frequency magnetic field-induced regeneration anomalies in the planarian, Dugesia tigrina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenrow, K.A.; Smith, C.H.; Liboff, A.R.

1996-12-31

The authors recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC magnetic fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. The authors report here, in a parallel series of investigations on the same model system, that the incidence of regeneration anomalies presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz magnetic fields, with peak intensities ranging between 1.0 and 80.0 {micro}T. These anomalies often culminate in the complete disaggregation of the organism. Similarmore » to regeneration rate effects, the incidence of regeneration anomalies is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied magnetic field vectors. However, unlike the regeneration rate effects, the AC magnetic field alone, in the absence of any measurable DC field, is capable of producing these anomalies. Moreover, the incidence of regeneration anomalies follows a clear dose-response relationship as a function of AC magnetic field intensity, with the threshold for induced electric field intensity estimated at 5 {micro} V/m. The addition of either 51.1 or 78.4 {micro}T DC magnetic fields, applied in parallel combination with the AC field, enhances the appearance of anomalies relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas the previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration anomalies reported here appear to result primarily from Faraday induction coupling.« less

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

1998-04-28

Active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing.

Weak extremely-low-frequency magnetic fields and regeneration in the planarian Dugesia tigrina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenrow, K.A.; Smith, C.H.; Liboff, A.R.

1995-06-01

Extremely-low-frequency (ELF), low-intensity magnetic fields have been shown to influence cell signaling processes in a variety of systems, both in vivo and in vitro. Similar effects have been demonstrated for nervous system development and neurite outgrowth. The authors report that regeneration in planaria, which incorporates many of these processes, is also affected by ELF magnetic fields. The rate of cephalic regeneration, reflected by the mean regeneration time (MRT), for planaria populations regenerating under continuous exposure to combined DC (78.4 {mu}T) and AC (60.0 Hz at 10.0 {mu}T{sub peak}) magnetic fields applied in parallel was found to be significantly delayed (Pmore » {much_lt} 0.001) by 48 {+-} 1 h relative to two different types of control populations (MRT {minus}140 {+-} 12 h). One control population was exposed to only the AC component of this field combination, while the other experienced only the ambient geomagnetic field. All measurements were conducted in a low-gradient, low-noise magnetics laboratory under well-maintained temperature conditions. This delay in regeneration was shown to be dependent on the planaria having a fixed orientation with respect to the magnetic field vectors. Results also indicate that this orientation-dependent transduction process does not result from Faraday induction but is consistent with a Ca{sup 2+} cyclotron resonance mechanism. Data interpretation also permits the tentative conclusion that the effect results from an inhibition of events at an early stage in the regeneration process before the onset of proliferation and differentiation.« less

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, K.A. Jr.; Pecharsky, V.K.

1998-04-28

Active magnetic regenerator and method using Gd{sub 5} (Si{sub x}Ge{sub 1{minus}x}){sub 4}, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd{sub 5} (Si{sub x} Ge{sub 1{minus}x}){sub 4}, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing. 27 figs.

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE PAGES

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry; ...

2018-05-19

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. Experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Early exposure of rotating magnetic fields promotes central nervous regeneration in planarian Girardia sinensis.

PubMed

Chen, Qiang; Lin, Gui-miao; Wu, Nan; Tang, Sheng-wei; Zheng, Zhi-jia; Lin, Marie Chia-mi; Xu, Gai-xia; Liu, Hao; Deng, Yue-yue; Zhang, Xiao-yun; Chen, Si-ping; Wang, Xiao-mei; Niu, Han-ben

2016-05-01

Magnetic field exposure is an accepted safe and effective modality for nerve injury. However, it is clinically used only as a supplement or salvage therapy at the later stage of treatment. Here, we used a planarian Girardia sinensis decapitated model to investigate beneficial effects of early rotary non-uniform magnetic fields (RMFs) exposure on central nervous regeneration. Our results clearly indicated that magnetic stimulation induced from early RMFs exposure significantly promoted neural regeneration of planarians. This stimulating effect is frequency and intensity dependent. Optimum effects were obtained when decapitated planarians were cultured at 20 °C, starved for 3 days before head-cutting, and treated with 6 Hz 0.02 T RMFs. At early regeneration stage, RMFs exposure eliminated edema around the wound and facilitated subsequent formation of blastema. It also accelerated cell proliferation and recovery of neuron functionality. Early RMFs exposure up-regulated expression of neural regeneration related proteins, EGR4 and Netrin 2, and mature nerve cell marker proteins, NSE and NPY. These results suggest that RMFs therapy produced early and significant benefit in central nervous regeneration, and should be clinically used at the early stage of neural regeneration, with appropriate optimal frequency and intensity. © 2016 Wiley Periodicals, Inc.

The Operating Principle of a Fully Solid State Active Magnetic Regenerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar

As an alternative refrigeration technology, magnetocaloric refrigeration has the potential to be safer, quieter, more efficient, and more environmentally friendly than the conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. This paper presents an operating principle of a fully solid state AMR, in which an alternative mechanism for heat transfer between the AMR and the heat source/sink is proposed. The operating principle of the fullymore » solid state AMR is based on moving rods/sheets (e.g. copper, brass, iron or aluminum), which are employed to replace the heat transfer fluid. Such fully solid state AMR would provide a significantly higher heat transfer rate than a conventional AMR because the conductivity of moving solid rods/plates is high and it enables the increase in the machine operating frequency hence the cooling capacity. The details of operating principle are presented and discussed here. One of the key enabling features for this technology is the contact between the moving rods/sheets and magnetocaloric material, and heat exchange mechanism at the heat source/sink. This paper provides an overview of the design for a fully solid state magnetocaloric refrigeration system along with guidelines for their optimal design.« less

Activated carbon/Fe(3)O(4) nanoparticle composite: fabrication, methyl orange removal and regeneration by hydrogen peroxide.

PubMed

Do, Manh Huy; Phan, Ngoc Hoa; Nguyen, Thi Dung; Pham, Thi Thu Suong; Nguyen, Van Khoa; Vu, Thi Thuy Trang; Nguyen, Thi Kim Phuong

2011-11-01

In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe(3)O(4) nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe(3)O(4) nanoparticles, were fabricated by a modified impregnation method using HNO(3) as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO(3) (powdered activated carbon modified by HNO(3)) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe(3)O(4) nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide. Copyright © 2011 Elsevier Ltd. All rights reserved.

Organic solvent regeneration of granular activated carbon

NASA Astrophysics Data System (ADS)

Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

1982-09-01

The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

Early bioelectric activities mediate redox-modulated regeneration

PubMed Central

Ferreira, Fernando; Luxardi, Guillaume; Reid, Brian

2016-01-01

Reactive oxygen species (ROS) and electric currents modulate regeneration; however, the interplay between biochemical and biophysical signals during regeneration remains poorly understood. We investigate the interactions between redox and bioelectric activities during tail regeneration in Xenopus laevis tadpoles. We show that inhibition of NADPH oxidase-mediated production of ROS, or scavenging or blocking their diffusion into cells, impairs regeneration and consistently regulates the dynamics of membrane potential, transepithelial potential (TEP) and electric current densities (JI) during regeneration. Depletion of ROS mimics the altered TEP and JI observed in the non-regenerative refractory period. Short-term application of hydrogen peroxide (H2O2) rescues (from depleted ROS) and induces (from the refractory period) regeneration, TEP increase and JI reversal. H2O2 is therefore necessary for and sufficient to induce regeneration and to regulate TEP and JI. Epistasis assays show that voltage-gated Na+ channels act downstream of H2O2 to modulate regeneration. Altogether, these results suggest a novel mechanism for regeneration via redox-bioelectric orchestration. PMID:27827821

Early bioelectric activities mediate redox-modulated regeneration.

PubMed

Ferreira, Fernando; Luxardi, Guillaume; Reid, Brian; Zhao, Min

2016-12-15

Reactive oxygen species (ROS) and electric currents modulate regeneration; however, the interplay between biochemical and biophysical signals during regeneration remains poorly understood. We investigate the interactions between redox and bioelectric activities during tail regeneration in Xenopus laevis tadpoles. We show that inhibition of NADPH oxidase-mediated production of ROS, or scavenging or blocking their diffusion into cells, impairs regeneration and consistently regulates the dynamics of membrane potential, transepithelial potential (TEP) and electric current densities (J I ) during regeneration. Depletion of ROS mimics the altered TEP and J I observed in the non-regenerative refractory period. Short-term application of hydrogen peroxide (H 2 O 2 ) rescues (from depleted ROS) and induces (from the refractory period) regeneration, TEP increase and J I reversal. H 2 O 2 is therefore necessary for and sufficient to induce regeneration and to regulate TEP and J I Epistasis assays show that voltage-gated Na + channels act downstream of H 2 O 2 to modulate regeneration. Altogether, these results suggest a novel mechanism for regeneration via redox-bioelectric orchestration. © 2016. Published by The Company of Biologists Ltd.

UV-activated persulfate oxidation and regeneration of NOM-Saturated granular activated carbon.

PubMed

An, Dong; Westerhoff, Paul; Zheng, Mengxin; Wu, Mengyuan; Yang, Yu; Chiu, Chao-An

2015-04-15

A new method of ultraviolet light (UV) activated persulfate (PS) oxidation was investigated to regenerate granular activated carbon (GAC) in drinking water applications. The improvements in iodine and methylene blue numbers measured in the GAC after ultraviolet- (UV) activated persulfate suggested that the GAC preloaded with natural organic matter (NOM) was chemically regenerated. An experimental matrix for UV-activated persulfate regeneration included a range of persulfate doses and different UV wavelengths. Over 87% of the initial iodine number for GAC was restored under the optimum conditions, perfulfate dosage 60 g/L and UV exposure 1.75 × 10(4) mJ/cm(2). The persulfate dosages had little effect on the recovery of the methylene blue number, which was approximately 65%. Persulfate activation at 185 nm was superior to activation at 254 nm. UV activation of persulfate in the presence of GAC produced acid, lowering the solution pH. Higher persulfate concentrations and UV exposure resulted in greater GAC regeneration. Typical organic and inorganic byproducts (e.g., benzene compounds and sulfate ions) were measured as a component of treated water quality safety. This study provides a proof-of-concept that can be used to optimize pilot-scale and full-scale UV-activated persulfate for regeneration of NOM-saturated GAC. Copyright © 2015 Elsevier Ltd. All rights reserved.

Erbium-based magnetic refrigerant (regenerator) for passive cryocooler

DOEpatents

Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

1996-07-23

A two stage Gifford-McMahon cryocooler having a low temperature stage for reaching approximately 10K, wherein the low temperature stage includes a passive magnetic heat regenerator selected from the group consisting of Er.sub.6 Ni.sub.2 Sn, Er.sub.6 Ni.sub.2 Pb, Er.sub.6 Ni.sub.2 (Sn.sub.0.75 Ga.sub.0.25), and Er.sub.9 Ni.sub.3 Sn comprising a mixture of Er.sub.3 Ni and Er.sub.6 Ni.sub.2 Sn in the microstructure.

Erbium-based magnetic refrigerant (regenerator) for passive cryocooler

DOEpatents

Gschneidner, K.A. Jr.; Pecharsky, V.K.

1996-07-23

A two stage Gifford-McMahon cryocooler is disclosed having a low temperature stage for reaching approximately 10K, wherein the low temperature stage includes a passive magnetic heat regenerator selected from the group consisting of Er{sub 6}Ni{sub 2}Sn, Er{sub 6}Ni{sub 2}Pb, Er{sub 6}Ni{sub 2}(Sn{sub 0.75}Ga{sub 0.25}), and Er{sub 9}Ni{sub 3}Sn comprising a mixture of Er{sub 3}Ni and Er{sub 6}Ni{sub 2}Sn in the microstructure. 14 figs.

Fenton-Driven Regeneration of MTBE-spent Granular Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves the combined, synergistic use of two treatment technologies: adsorption of organic chemicals onto activated carbon and Fenton-driven oxidation regeneration of the spent-GAC...

Electrochemical regeneration of phenol-saturated activated carbon - proposal of a reactor.

PubMed

Zanella, Odivan; Bilibio, Denise; Priamo, Wagner Luiz; Tessaro, Isabel Cristina; Féris, Liliana Amaral

2017-03-01

An electrochemical process was used to investigate the activated carbon regeneration efficiency (RE) saturated with aromatics. For this purpose, an electrochemical reactor was developed and the operational conditions of this equipment were investigated, which is applied in activated carbon regeneration process. The influence of regeneration parameters such as processing time, the current used, the polarity and the processing fluid (electrolyte) were studied. The performance of electrochemical regeneration was evaluated by adsorption tests, using phenol as adsorbate. The increase in current applied and the process time was found to enhance the RE. Another aspect that indicated a better reactor performance was the type of electrolyte used, showing best results for NaCl. The polarity showed the highest influence on the process, when the cathodic regeneration was more efficient. The electrochemical regeneration process developed in this study presented regeneration capacities greater than 100% when the best process conditions were used, showing that this form of regeneration for activated carbon saturated with aromatics is very promising.

Novel electro-fenton approach for regeneration of activated carbon.

PubMed

Bañuelos, Jennifer A; Rodríguez, Francisco J; Manríquez Rocha, Juan; Bustos, Erika; Rodríguez, Adrián; Cruz, Julio C; Arriaga, L G; Godínez, Luis A

2013-07-16

An electro-Fenton-based method was used to promote the regeneration of granular activated carbon (GAC) previously adsorbed with toluene. Electrochemical regeneration experiments were carried out using a standard laboratory electrochemical cell with carbon paste electrodes and a batch electrochemical reactor. For each system, a comparison was made using FeSO4 as a precursor salt in solution (homogeneous system) and an Fe-loaded ion-exchange resin (Purolite C-100, heterogeneous system), both in combination with electrogenerated H2O2 at the GAC cathode. In the two cases, high regeneration efficiencies were obtained in the presence of iron using appropriate conditions of applied potential and adsorption-polarization time. Consecutive loading and regeneration cycles of GAC were performed in the reactor without great loss of the adsorption properties, only reducing the regeneration efficiency by 1% per cycle during 10 cycles of treatment. Considering that, in the proposed resin-containing process, the use of Fe salts is avoided and that GAC cathodic polarization results in efficient cleaning and regeneration of the adsorbent material, this novel electro-Fenton approach could constitute an excellent alternative for regenerating activated carbon when compared to conventional methods.

Regenerable activated bauxite adsorbent alkali monitor probe

DOEpatents

Lee, S.H.D.

1992-12-22

A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases. 6 figs.

Extended magnetic resonance imaging studies on the effect of classically activated microglia transplantation on white matter regeneration following spinal cord focal injury in adult rats

PubMed Central

Marcol, Wiesław; Ślusarczyk, Wojciech; Larysz-Brysz, Magdalena; Łabuzek, Krzysztof; Kapustka, Bartosz; Staszkiewicz, Rafał; Rosicka, Paulina; Kalita, Katarzyna; Węglarz, Władysław; Lewin-Kowalik, Joanna

2017-01-01

Spinal cord injuries are still a serious problem for regenerative medicine. Previous research has demonstrated that activated microglia accumulate in spinal lesions, influencing the injured tissues in various ways. Therefore, transplantation of activated microglia may have a beneficial role in the regeneration of the nervous system. The present study examined the influence of transplanted activated microglial cells in adult rats with injured spinal cords. Rats were randomly divided into an experimental (M) and control (C) group, and were subjected to non-laminectomy focal injury of spinal cord white matter by means of a high-pressured air stream. In group M, activated cultured microglial cells were injected twice into the site of injury. Functional outcome and morphological features of regeneration were analyzed during a 12-week follow-up. The lesions were characterized by means of magnetic resonance imaging (MRI). Neurons in the brain stem and motor cortex were labeled with FluoroGold (FG). A total of 12 weeks after surgery, spinal cords and brains were collected and subjected to histopathological and immunohistochemical examinations. Lesion sizes in the spinal cord were measured and the number of FG-positive neurons was counted. Rats in group M demonstrated significant improvement of locomotor performance when compared with group C (P<0.05). MRI analysis demonstrated moderate improvement in water diffusion along the spinal cord in the group M following microglia treatment, as compared with group C. The water diffusion perpendicular to the spinal cord in group M was closer to the reference values for a healthy spinal cord than it was in group C. The sizes of lesions were also significantly smaller in group M than in the group C (P<0.05). The number of brain stem and motor cortex FG-positive neurons in group M was significantly higher than in group C. The present study demonstrated that delivery of activated microglia directly into the injured spinal cord gives

Myocardial NF-κB activation is essential for zebrafish heart regeneration

PubMed Central

Karra, Ravi; Knecht, Anne K.; Kikuchi, Kazu; Poss, Kenneth D.

2015-01-01

Heart regeneration offers a novel therapeutic strategy for heart failure. Unlike mammals, lower vertebrates such as zebrafish mount a strong regenerative response following cardiac injury. Heart regeneration in zebrafish occurs by cardiomyocyte proliferation and reactivation of a cardiac developmental program, as evidenced by induction of gata4 regulatory sequences in regenerating cardiomyocytes. Although many of the cellular determinants of heart regeneration have been elucidated, how injury triggers a regenerative program through dedifferentiation and epicardial activation is a critical outstanding question. Here, we show that NF-κB signaling is induced in cardiomyocytes following injury. Myocardial inhibition of NF-κB activity blocks heart regeneration with pleiotropic effects, decreasing both cardiomyocyte proliferation and epicardial responses. Activation of gata4 regulatory sequences is also prevented by NF-κB signaling antagonism, suggesting an underlying defect in cardiomyocyte dedifferentiation. Our results implicate NF-κB signaling as a key node between cardiac injury and tissue regeneration. PMID:26472034

Myocardial NF-κB activation is essential for zebrafish heart regeneration.

PubMed

Karra, Ravi; Knecht, Anne K; Kikuchi, Kazu; Poss, Kenneth D

2015-10-27

Heart regeneration offers a novel therapeutic strategy for heart failure. Unlike mammals, lower vertebrates such as zebrafish mount a strong regenerative response following cardiac injury. Heart regeneration in zebrafish occurs by cardiomyocyte proliferation and reactivation of a cardiac developmental program, as evidenced by induction of gata4 regulatory sequences in regenerating cardiomyocytes. Although many of the cellular determinants of heart regeneration have been elucidated, how injury triggers a regenerative program through dedifferentiation and epicardial activation is a critical outstanding question. Here, we show that NF-κB signaling is induced in cardiomyocytes following injury. Myocardial inhibition of NF-κB activity blocks heart regeneration with pleiotropic effects, decreasing both cardiomyocyte proliferation and epicardial responses. Activation of gata4 regulatory sequences is also prevented by NF-κB signaling antagonism, suggesting an underlying defect in cardiomyocyte dedifferentiation. Our results implicate NF-κB signaling as a key node between cardiac injury and tissue regeneration.

Sustainable Regeneration of Nanoparticle Enhanced Activated Carbon in Water

EPA Science Inventory

The regeneration and reuse of exhausted granular activated carbon (GAC) is an appropriate method for lowering operational and environmental costs. Advanced oxidation is a promising environmental friendly technique for GAC regeneration. The main objective of this research was to ...

PERSPECTIVE: Electrical activity enhances neuronal survival and regeneration

NASA Astrophysics Data System (ADS)

Corredor, Raul G.; Goldberg, Jeffrey L.

2009-10-01

The failure of regeneration in the central nervous system (CNS) remains an enormous scientific and clinical challenge. After injury or in degenerative diseases, neurons in the adult mammalian CNS fail to regrow their axons and reconnect with their normal targets, and furthermore the neurons frequently die and are not normally replaced. While significant progress has been made in understanding the molecular basis for this lack of regenerative ability, a second approach has gained momentum: replacing lost neurons or lost connections with artificial electrical circuits that interface with the nervous system. In the visual system, gene therapy-based 'optogenetics' prostheses represent a competing technology. Now, the two approaches are converging, as recent data suggest that electrical activity itself, via the molecular signaling pathways such activity stimulates, is sufficient to induce neuronal survival and regeneration, particularly in retinal ganglion cells. Here, we review these data, discuss the effects of electrical activity on neurons' molecular signaling pathways and propose specific mechanisms by which exogenous electrical activity may be acting to enhance survival and regeneration.

Active Nanomaterials to Meet the Challenge of Dental Pulp Regeneration

PubMed Central

Keller, Laetitia; Offner, Damien; Schwinté, Pascale; Morand, David; Wagner, Quentin; Gros, Catherine; Bornert, Fabien; Bahi, Sophie; Musset, Anne-Marie; Benkirane-Jessel, Nadia; Fioretti, Florence

2015-01-01

The vitality of the pulp is fundamental to the functional life of the tooth. For this aim, active and living biomaterials are required to avoid the current drastic treatment, which is the removal of all the cellular and molecular content regardless of its regenerative potential. The regeneration of the pulp tissue is the dream of many generations of dental surgeons and will revolutionize clinical practices. Recently, the potential of the regenerative medicine field suggests that it would be possible to achieve such complex regeneration. Indeed, three crucial steps are needed: the control of infection and inflammation and the regeneration of lost pulp tissues. For regenerative medicine, in particular for dental pulp regeneration, the use of nano-structured biomaterials becomes decisive. Nano-designed materials allow the concentration of many different functions in a small volume, the increase in the quality of targeting, as well as the control of cost and delivery of active molecules. Nanomaterials based on extracellular mimetic nanostructure and functionalized with multi-active therapeutics appear essential to reverse infection and inflammation and concomitantly to orchestrate pulp cell colonization and differentiation. This novel generation of nanomaterials seems very promising to meet the challenge of the complex dental pulp regeneration. PMID:28793649

Boosting CNS axon regeneration by harnessing antagonistic effects of GSK3 activity.

PubMed

Leibinger, Marco; Andreadaki, Anastasia; Golla, Renate; Levin, Evgeny; Hilla, Alexander M; Diekmann, Heike; Fischer, Dietmar

2017-07-03

Implications of GSK3 activity for axon regeneration are often inconsistent, if not controversial. Sustained GSK3 activity in GSK3 S/A knock-in mice reportedly accelerates peripheral nerve regeneration via increased MAP1B phosphorylation and concomitantly reduces microtubule detyrosination. In contrast, the current study shows that lens injury-stimulated optic nerve regeneration was significantly compromised in these knock-in mice. Phosphorylation of MAP1B and CRMP2 was expectedly increased in retinal ganglion cell (RGC) axons upon enhanced GSK3 activity, but, surprisingly, no GSK3-mediated CRMP2 inhibition was detected in sciatic nerves, thus revealing a fundamental difference between central and peripheral axons. Conversely, genetic or shRNA-mediated conditional KO/knockdown of GSK3β reduced inhibitory phosphorylation of CRMP2 in RGCs and improved optic nerve regeneration. Accordingly, GSK3β KO-mediated neurite growth promotion and myelin disinhibition were abrogated by CRMP2 inhibition and largely mimicked in WT neurons upon expression of constitutively active CRMP2 (CRMP2 T/A ). These results underscore the prevalent requirement of active CRMP2 for optic nerve regeneration. Strikingly, expression of CRMP2 T/A in GSK3 S/A RGCs further boosted optic nerve regeneration, with axons reaching the optic chiasm within 3 wk. Thus, active GSK3 can also markedly promote axonal growth in central nerves if CRMP2 concurrently remains active. Similar to peripheral nerves, GSK3-mediated MAP1B phosphorylation/activation and the reduction of microtubule detyrosination contributed to this effect. Overall, these findings reconcile conflicting data on GSK3-mediated axon regeneration. In addition, the concept of complementary modulation of normally antagonistically targeted GSK3 substrates offers a therapeutically applicable approach to potentiate the regenerative outcome in the injured CNS.

Bone structure regeneration after low induction magnetic field treatment in teeth chosen for extraction.

PubMed

Opalko, K; Dojs, A

2006-01-01

The aim of the work was to use and to evaluate the usefulness of the slow variable magnetic fields to aid the treatment of the teeth chosen for extraction. The marginal paradontium of periapical bone of teeth was in a state of extensive destruction. The teeth were chosen for extraction. 13 patients were chosen. 10 of them had with endo-perio changes and 3 suffered from full tooth luxation and had the teeth replanted. Those people were to have an extraction procedure or were declared as impossible to treat in other dental offices. Patients underwent non-aggressive skaling, endodontic treatment and were exposed to slow variable magnetic fields generated by Viofor JPS, accordingly to methods and parameters suggested by Department of Propaedeutics in Dentistry of Pomeranian Medical University in Szczecin. The process of healing of changes was evaluated radiologically. RTG done after 2 weeks and after 2 months were evaluated in respect of bone regeneration. They show the bone structure concentration. A RTG evaluation after half a year, two and three years show a preservation of the bone structure concentration. The use of slow variable magnetic fields contributed to bone structure regeneration and to preserve teeth with recorded endo-perio syndrome. Endodontic treatment of replanted teeth, aided with magnetostimulation has stopped the osteolisis process.

Investigation on the two-stage active magnetic regenerative refrigerator for liquefaction of hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Inmyong; Park, Jiho; Jeong, Sangkwon

2014-01-29

An active magnetic regenerative refrigerator (AMRR) is expected to be useful for hydrogen liquefaction due to its inherent high thermodynamic efficiency. Because the temperature of the cold end of the refrigerator has to be approximately liquid temperature, a large temperature span of the active magnetic regenerator (AMR) is indispensable when the heat sink temperature is liquid nitrogen temperature or higher. Since magnetic refrigerants are only effective in the vicinity of their own transition temperatures, which limit the temperature span of the AMR, an innovative structure is needed to increase the temperature span. The AMR must be a layered structure andmore » the thermophysical matching of magnetic field and flow convection effects is very important. In order to design an AMR for liquefaction of hydrogen, the implementation of multi-layered AMR with different magnetic refrigerants is explored with multi-staging. In this paper, the performance of the multi-layered AMR using four rare-earth compounds (GdNi{sub 2}, Gd{sub 0.1}Dy{sub 0.9}Ni{sub 2}, Dy{sub 0.85}Er{sub 0.15}Al{sub 2}, Dy{sub 0.5}Er{sub 0.5}Al{sub 2}) is investigated. The experimental apparatus includes two-stage active magnetic regenerator containing two different magnetic refrigerants each. A liquid nitrogen reservoir connected to the warm end of the AMR maintains the temperature of the warm end around 77 K. High-pressure helium gas is employed as a heat transfer fluid in the AMR and the maximum magnetic field of 4 T is supplied by the low temperature superconducting (LTS) magnet. The temperature span with the variation of parameters such as phase difference between magnetic field and mass flow rate of magnetic refrigerants in AMR is investigated. The maximum temperature span in the experiment is recorded as 50 K and several performance issues have been discussed in this paper.« less

V-ATPase proton pumping activity is required for adult zebrafish appendage regeneration.

PubMed

Monteiro, Joana; Aires, Rita; Becker, Jörg D; Jacinto, António; Certal, Ana C; Rodríguez-León, Joaquín

2014-01-01

The activity of ion channels and transporters generates ion-specific fluxes that encode electrical and/or chemical signals with biological significance. Even though it is long known that some of those signals are crucial for regeneration, only in recent years the corresponding molecular sources started to be identified using mainly invertebrate or larval vertebrate models. We used adult zebrafish caudal fin as a model to investigate which and how ion transporters affect regeneration in an adult vertebrate model. Through the combined use of biophysical and molecular approaches, we show that V-ATPase activity contributes to a regeneration-specific H+ ef`flux. The onset and intensity of both V-ATPase expression and H+ efflux correlate with the different regeneration rate along the proximal-distal axis. Moreover, we show that V-ATPase inhibition impairs regeneration in adult vertebrate. Notably, the activity of this H+ pump is necessary for aldh1a2 and mkp3 expression, blastema cell proliferation and fin innervation. To the best of our knowledge, this is the first report on the role of V-ATPase during adult vertebrate regeneration.

V-ATPase Proton Pumping Activity Is Required for Adult Zebrafish Appendage Regeneration

PubMed Central

Monteiro, Joana; Aires, Rita; Becker, Jörg D.; Jacinto, António; Certal, Ana C.; Rodríguez-León, Joaquín

2014-01-01

The activity of ion channels and transporters generates ion-specific fluxes that encode electrical and/or chemical signals with biological significance. Even though it is long known that some of those signals are crucial for regeneration, only in recent years the corresponding molecular sources started to be identified using mainly invertebrate or larval vertebrate models. We used adult zebrafish caudal fin as a model to investigate which and how ion transporters affect regeneration in an adult vertebrate model. Through the combined use of biophysical and molecular approaches, we show that V-ATPase activity contributes to a regeneration-specific H+ ef`flux. The onset and intensity of both V-ATPase expression and H+ efflux correlate with the different regeneration rate along the proximal-distal axis. Moreover, we show that V-ATPase inhibition impairs regeneration in adult vertebrate. Notably, the activity of this H+ pump is necessary for aldh1a2 and mkp3 expression, blastema cell proliferation and fin innervation. To the best of our knowledge, this is the first report on the role of V-ATPase during adult vertebrate regeneration. PMID:24671205

SRC activates TAZ for intestinal tumorigenesis and regeneration.

PubMed

Byun, Mi Ran; Hwang, Jun-Ha; Kim, A Rum; Kim, Kyung Min; Park, Jung Il; Oh, Ho Taek; Hwang, Eun Sook; Hong, Jeong-Ho

2017-12-01

Proto-oncogene tyrosine-protein kinase Src (cSRC) is involved in colorectal cancer (CRC) development and damage-induced intestinal regeneration, although the cellular mechanisms involved are poorly understood. Here, we report that transcriptional coactivator with PDZ binding domain (TAZ) is activated by cSRC, regulating CRC cell proliferation and tumor formation, where cSRC overexpression increases TAZ expression in CRC cells. In contrast, knockdown of cSRC decreases TAZ expression. Additionally, direct phosphorylation of TAZ at Tyr316 by cSRC stimulates nuclear localization and facilitates transcriptional enhancer factor TEF-3 (TEAD4)-mediated transcription. However, a TAZ phosphorylation mutant significantly decreased cell proliferation, wound healing, colony forming, and tumor formation. In a CRC mouse model, Apc Min/+ , activated SRC expression was associated with increased TAZ expression in polyps and TAZ depletion decreased polyp formation. Moreover, intestinal TAZ knockout mice had intestinal regeneration defects following γ-irradiation. Finally, significant correspondence between SRC activation and TAZ overexpression was observed in CRC patients. These results suggest that TAZ is a critical factor for SRC-mediated intestinal tumor formation and regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Persulfate Oxidation Regeneration of Granular Activated Carbon: Reversible Impacts on Sorption Behavior

EPA Science Inventory

Chemical oxidation regeneration of granular activated carbon (GAC) is a developing technology that can be carried out utilizing thermally-activated persulfate. During chemical regeneration of GAC, aggressive oxidative conditions lead to high acidity (pH < 2) and the accumulation ...

Synergistic interactions between temporal coupling of complex light and magnetic pulses upon melanoma cell proliferation and planarian regeneration.

PubMed

Murugan, Nirosha J; Karbowski, Lukasz M; Persinger, Michael A

2017-01-01

Synergisms between a physiologically patterned magnetic field that is known to enhance planarian growth and suppress proliferation of malignant cells in culture and three light emitting diode (LED) generated visible wavelengths (blue, green, red) upon planarian regeneration and melanoma cell numbers were discerned. Five days of hourly exposures to either a physiologically patterned (2.5-5.0 μT) magnetic field, one of three wavelengths (3 kLux) or both treatments simultaneously indicated that red light (680 nm), blue light (470 nm) or the magnetic field significantly facilitated regeneration of planarian compared to sham field exposed planarian. Presentation of both light and magnetic field conditions enhanced the effect. Whereas the blue and red light diminished the growth of malignant (melanoma) cells, the effect was not as large as that produced by the magnetic field. Only the paired presentation of the blue light and magnetic field enhanced the suppression. On the other hand, the changes following green light (540 nm) exposure did not differ from the control condition and green light presented with the magnetic field eliminated its effects for both the planarian and melanoma cells. These results indicate specific colors affect positive adaptation that is similar to weak, physiologically patterned frequency modulated (8-24 Hz) magnetic fields and that the two forms of energy can synergistically summate or cancel.

Photospheric magnetic fields

NASA Technical Reports Server (NTRS)

Howard, R.

1972-01-01

Knowledge on the nature of magnetic fields on the solar surface is reviewed. At least a large part of the magnetic flux in the solar surface is confined to small bundles of lines of force within which the field strength is of the order of 500 gauss. Magnetic fields are closely associated with all types of solar activity. Magnetic flux appears at the surface at the clearly defined birth or regeneration of activity of an active region. As the region ages, the magnetic flux migrates to form large-scale patterns and the polar fields. Some manifestations of the large-scale distribution are discussed.

Fenton- and Persulfate-driven Regeneration of Contaminant-spent Granular Activated Carbon

EPA Science Inventory

Fenton- or persulfate-driven chemical oxidation regeneration of spent granular activated carbon (GAC) involves the combined, synergistic use of two treatment technologies: adsorption of organic chemicals onto GAC and chemical oxidation regeneration of the spent-GAC. Environmental...

WIND1 Promotes Shoot Regeneration through Transcriptional Activation of ENHANCER OF SHOOT REGENERATION1 in Arabidopsis[OPEN

PubMed Central

Ohnuma, Mariko; Kurata, Tetsuya; Nakata, Masaru; Ohme-Takagi, Masaru

2017-01-01

Many plant species display remarkable developmental plasticity and regenerate new organs after injury. Local signals produced by wounding are thought to trigger organ regeneration but molecular mechanisms underlying this control remain largely unknown. We previously identified an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION1 (WIND1) as a central regulator of wound-induced cellular reprogramming in plants. In this study, we demonstrate that WIND1 promotes callus formation and shoot regeneration by upregulating the expression of the ENHANCER OF SHOOT REGENERATION1 (ESR1) gene, which encodes another AP2/ERF transcription factor in Arabidopsis thaliana. The esr1 mutants are defective in callus formation and shoot regeneration; conversely, its overexpression promotes both of these processes, indicating that ESR1 functions as a critical driver of cellular reprogramming. Our data show that WIND1 directly binds the vascular system-specific and wound-responsive cis-element-like motifs within the ESR1 promoter and activates its expression. The expression of ESR1 is strongly reduced in WIND1-SRDX dominant repressors, and ectopic overexpression of ESR1 bypasses defects in callus formation and shoot regeneration in WIND1-SRDX plants, supporting the notion that ESR1 acts downstream of WIND1. Together, our findings uncover a key molecular pathway that links wound signaling to shoot regeneration in plants. PMID:28011694

Bone regeneration with biomaterials and active molecules delivery.

PubMed

D' Este, Matteo; Eglin, David; Alini, Mauro; Kyllonen, Laura

2015-01-01

The combination of biomaterials and drug delivery strategies is a promising avenue towards improved synthetic bone substitutes. With the delivery of active species biomaterials can be provided with the bioactivity they still lack for improved bone regeneration. Recently, a lot of research efforts have been put towards this direction. Biomaterials for bone regeneration have been supplemented with small or biological molecules for improved osteoprogenitor cell recruitment, osteoinductivity, anabolic or angiogenic response, regulation of bone metabolism and others. The scope of this review is to summarize the most recent results in this field.

Magnetotherapy: The quest for tendon regeneration.

PubMed

Pesqueira, Tamagno; Costa-Almeida, Raquel; Gomes, Manuela E

2018-05-09

Tendons are mechanosensitive tissues that connect and transmit the forces generated by muscles to bones by allowing the conversion of mechanical input into biochemical signals. These physical forces perform the fundamental work of preserving tendon homeostasis assuring body movements. However, overloading causes tissue injuries, which leads us to the field of tendon regeneration. Recently published reviews have broadly shown the use of biomaterials and different strategies to attain tendon regeneration. In this review, our focus is the use of magnetic fields as an alternative therapy, which has demonstrated clinical relevance in tendon medicine because of their ability to modulate cell fate. Yet the underlying cellular and molecular mechanisms still need to be elucidated. While providing a brief outlook about specific signalling pathways and intracellular messengers as framework in play by tendon cells, application of magnetic fields as a subcategory of physical forces is explored, opening up a compelling avenue to enhance tendon regeneration. We outline here useful insights on the effects of magnetic fields both at in vitro and in vivo levels, particularly on the expression of tendon genes and inflammatory cytokines, ultimately involved in tendon regeneration. Subsequently, the potential of using magnetically responsive biomaterials in tendon tissue engineering is highlighted and future directions in magnetotherapy are discussed. © 2018 Wiley Periodicals, Inc.

Effects of microwave heating on porous structure of regenerated powdered activated carbon used in xylose.

PubMed

Li, Wei; Wang, Xinying; Peng, Jinhui

2014-01-01

The regeneration of spent powdered activated carbons used in xylose decolourization by microwave heating was investigated. Effects of microwave power and microwave heating time on the adsorption capacity of regenerated activated carbons were evaluated. The optimum conditions obtained are as follows: microwave power 800W; microwave heating time 30min. Regenerated activated carbon in this work has high adsorption capacities for the amount of methylene blue of 16 cm3/0.1 g and the iodine number of 1000.06mg/g. The specific surface areas of fresh commercial activated carbon, spent carbon and regenerated activated carbon were calculated according to the Brunauer, Emmett and Teller method, and the pore-size distributions of these carbons were characterized by non-local density functional theory (NLDFT). The results show that the specific surface area and the total pore volume of regenerated activated carbon are 1064 m2/g and 1.181 mL/g, respectively, indicating the feasibility of regeneration of spent powdered activated carbon used in xylose decolourization by microwave heating. The results of surface fractal dimensions also confirm the results of isotherms and NLDFT.

Regeneration of sulfamethoxazole-saturated activated carbon using gamma irradiation

NASA Astrophysics Data System (ADS)

Chu, Libing; Wang, Jianlong

2017-01-01

Activated carbon (AC) has been widely used for reclamation and reuse of the effluent of wastewater treatment plant to further remove the emerging contaminants, such as PPCPs in recent years. How to regenerate the exhausted AC effectively and economically is still a challenge. In the present study, the regeneration of AC exhausted with SMX was performed by gamma irradiation to simultaneously recover the spent AC and degrade the pollutants. The results showed that the adsorption of SMX onto AC can be described by the Langmuir isotherm and the adsorption capacity was about 417 mg/g. SMX can be removed rapidly when exposed to gamma irradiation, with the initial concentration of 100 mg/L, more than 99% of SMX was removed at 5.0 kGy, while an extremely high dose (150 kGy) was needed to reach 80% mineralization ratio. The regeneration efficiency was about 21-30% at 50-200 kGy. The absorbed SMX and the intermediates formed during gamma irradiation were released into aqueous solution from AC and mineralized, leading to the partial regeneration of the adsorption capacity of AC. Further studies are needed to optimize the experimental conditions to increase the regeneration efficiency.

Wnt activation followed by Notch inhibition promotes mitotic hair cell regeneration in the postnatal mouse cochlea

PubMed Central

Li, Wenyan; Chen, Yan; Zhang, Shasha; Tang, Mingliang; Sun, Shan; Chai, Renjie; Li, Huawei

2016-01-01

Hair cell (HC) loss is the main cause of permanent hearing loss in mammals. Previous studies have reported that in neonatal mice cochleae, Wnt activation promotes supporting cell (SC) proliferation and Notch inhibition promotes the trans-differentiation of SCs into HCs. However, Wnt activation alone fails to regenerate significant amounts of new HCs, Notch inhibition alone regenerates the HCs at the cost of exhausting the SC population, which leads to the death of the newly regenerated HCs. Mitotic HC regeneration might preserve the SC number while regenerating the HCs, which could be a better approach for long-term HC regeneration. We present a two-step gene manipulation, Wnt activation followed by Notch inhibition, to accomplish mitotic regeneration of HCs while partially preserving the SC number. We show that Wnt activation followed by Notch inhibition strongly promotes the mitotic regeneration of new HCs in both normal and neomycin-damaged cochleae while partially preserving the SC number. Lineage tracing shows that the majority of the mitotically regenerated HCs are derived specifically from the Lgr5+ progenitors with or without HC damage. Our findings suggest that the co-regulation of Wnt and Notch signaling might provide a better approach to mitotically regenerate HCs from Lgr5+ progenitor cells. PMID:27564256

Low temperature regeneration of activated carbons using microwaves: revising conventional wisdom.

PubMed

Calışkan, E; Bermúdez, J M; Parra, J B; Menéndez, J A; Mahramanlıoğlu, M; Ania, C O

2012-07-15

The purpose of this work was to explore the application of microwaves for the low temperature regeneration of activated carbons saturated with a pharmaceutical compound (promethazine). Contrary to expectations, microwave-assisted regeneration did not lead to better results than those obtained under conventional electric heating. At low temperatures the regeneration was incomplete either under microwave and conventional heating, being this attributed to the insufficient input energy. At mild temperatures, a fall in the adsorption capacity upon cycling was obtained in both devices, although this was much more pronounced for the microwave. These results contrast with previous studies on the benefits of microwaves for the regeneration of carbon materials. The fall in the adsorption capacity after regeneration was due to the thermal cracking of the adsorbed molecules inside the carbon porous network, although this effect applies to both devices. When microwaves are used, along with the thermal heating of the carbon bed, a fraction of the microwave energy seemed to be directly used in the decomposition of promethazine through the excitation of the molecular bonds by microwaves (microwave-lysis). These results point out that the nature of the adsorbate and its ability to interact with microwave are key factors that control the application of microwaves for regeneration of exhausted activated carbons. Copyright © 2012 Elsevier Ltd. All rights reserved.

PERFORMANCE OF ACTIVATED SLUDGE-POWDERED ACTIVATED CARBON-WET AIR REGENERATION SYSTEMS

EPA Science Inventory

The investigation summarized in the report was undertaken to evaluate the performance of powdered activated carbon (PAC) technology used in conjunction with wet air regeneration (WAR) at municipal wastewater treatment plants. Excessive ash concentrations accumulated in the mixed ...

AMP-activated Protein Kinase Stimulates Warburg-like Glycolysis and Activation of Satellite Cells during Muscle Regeneration*

PubMed Central

Fu, Xing; Zhu, Mei-Jun; Dodson, Mike V.; Du, Min

2015-01-01

Satellite cells are the major myogenic stem cells residing inside skeletal muscle and are indispensable for muscle regeneration. Satellite cells remain largely quiescent but are rapidly activated in response to muscle injury, and the derived myogenic cells then fuse to repair damaged muscle fibers or form new muscle fibers. However, mechanisms eliciting metabolic activation, an inseparable step for satellite cell activation following muscle injury, have not been defined. We found that a noncanonical Sonic Hedgehog (Shh) pathway is rapidly activated in response to muscle injury, which activates AMPK and induces a Warburg-like glycolysis in satellite cells. AMPKα1 is the dominant AMPKα isoform expressed in satellite cells, and AMPKα1 deficiency in satellite cells impairs their activation and myogenic differentiation during muscle regeneration. Drugs activating noncanonical Shh promote proliferation of satellite cells, which is abolished because of satellite cell-specific AMPKα1 knock-out. Taken together, AMPKα1 is a critical mediator linking noncanonical Shh pathway to Warburg-like glycolysis in satellite cells, which is required for satellite activation and muscle regeneration. PMID:26370082

Retrotransposon long interspersed nucleotide element-1 (LINE-1) is activated during salamander limb regeneration

PubMed Central

Zhu, Wei; Kuo, Dwight; Nathanson, Jason; Satoh, Akira; Pao, Gerald M.; Yeo, Gene W.; Bryant, Susan V.; Voss, S. Randal; Gardiner, David M.; Hunter, Tony

2012-01-01

Salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. In our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. In this work, we focus on one of these genes, the long interspersed nucleotide element-1 (LINE-1) retrotransposon, which is usually active in germ cells and silent in most of the somatic tissues in other organisms. LINE-1 was found to be dramatically upregulated during regeneration. In addition, higher genomic LINE-1 content was also detected in the limb regenerate when compared to that before amputation indicating that LINE-1 retrotransposition is indeed active during regeneration. Active LINE-1 retrotransposition has been suggested to have a potentially deleterious impact on genomic integrity. Silencing of activated LINE-1 by small RNAs has been reported to be part of the machinery aiming to maintain genomic integrity. Indeed, we were able to identify putative LINE-1-related piRNAs in the limb blastema. Transposable element-related piRNAs have been identified frequently in the germline in other organisms. Thus, we present here a scenario in which a unique germline-like state is established during axolotl limb regeneration, and the re-activation of LINE-1 may serve as a marker for cellular dedifferentiation in the early-stage of limb regeneration. PMID:22913491

Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

PubMed Central

Im, Owen; Li, Jian; Wang, Mian; Zhang, Lijie Grace; Keidar, Michael

2012-01-01

Background Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT), biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan). Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels. Methods Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells) using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT) and without a magnetic field (N-SWCNT) for improving bone regeneration. Results Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment. Conclusion This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite promising for further exploration for bone regeneration. PMID:22619545

EGFR Activation Mediates Inhibition of Axon Regeneration by Myelin and Chondroitin Sulfate Proteoglycans

NASA Astrophysics Data System (ADS)

Koprivica, Vuk; Cho, Kin-Sang; Park, Jong Bae; Yiu, Glenn; Atwal, Jasvinder; Gore, Bryan; Kim, Jieun A.; Lin, Estelle; Tessier-Lavigne, Marc; Chen, Dong Feng; He, Zhigang

2005-10-01

Inhibitory molecules associated with myelin and the glial scar limit axon regeneration in the adult central nervous system (CNS), but the underlying signaling mechanisms of regeneration inhibition are not fully understood. Here, we show that suppressing the kinase function of the epidermal growth factor receptor (EGFR) blocks the activities of both myelin inhibitors and chondroitin sulfate proteoglycans in inhibiting neurite outgrowth. In addition, regeneration inhibitors trigger the phosphorylation of EGFR in a calcium-dependent manner. Local administration of EGFR inhibitors promotes significant regeneration of injured optic nerve fibers, pointing to a promising therapeutic avenue for enhancing axon regeneration after CNS injury.

Novel DLK-independent neuronal regeneration in Caenorhabditis elegans shares links with activity-dependent ectopic outgrowth

PubMed Central

Awal, Mehraj R.; Shay, James; McLoed, Melissa M.; Mazur, Eric; Gabel, Christopher V.

2016-01-01

During development, a neuron transitions from a state of rapid growth to a stable morphology, and neurons within the adult mammalian CNS lose their ability to effectively regenerate in response to injury. Here, we identify a novel form of neuronal regeneration, which is remarkably independent of DLK-1/DLK, KGB-1/JNK, and other MAPK signaling factors known to mediate regeneration in Caenorhabditis elegans, Drosophila, and mammals. This DLK-independent regeneration in C. elegans has direct genetic and molecular links to a well-studied form of endogenous activity-dependent ectopic axon outgrowth in the same neuron type. Both neuron outgrowth types are triggered by physical lesion of the sensory dendrite or mutations disrupting sensory activity, calcium signaling, or genes that restrict outgrowth during neuronal maturation, such as SAX-1/NDR kinase or UNC-43/CaMKII. These connections suggest that ectopic outgrowth represents a powerful platform for gene discovery in neuronal regeneration. Moreover, we note numerous similarities between C. elegans DLK-independent regeneration and lesion conditioning, a phenomenon producing robust regeneration in the mammalian CNS. Both regeneration types are triggered by lesion of a sensory neurite via reduction of neuronal activity and enhanced by disrupting L-type calcium channels or elevating cAMP. Taken as a whole, our study unites disparate forms of neuronal outgrowth to uncover fresh molecular insights into activity-dependent control of the adult nervous system’s intrinsic regenerative capacity. PMID:27078101

FENTON-DRIVEN REGENERATION OF GRANULAR ACTIVATED CARBON: A TECHNOLOGY OVERVIEW

EPA Science Inventory

A Fenton-driven mechanism for regenerating spent granular activated carbon (GAC) involves the combined, synergistic use of two reliable and well established treatment technologies - adsorption onto activated carbon and Fenton oxidation. During carbon adsorption treatment, enviro...

Micro RNAs are involved in activation of epicardium during zebrafish heart regeneration.

PubMed

Ceci, Marcello; Carlantoni, Claudia; Missinato, Maria Azzurra; Bonvissuto, Davide; Di Giacomo, Bruna; Contu, Riccardo; Romano, Nicla

2018-01-01

Zebrafish could be an interesting translational model to understand and improve the post-infarction trial and possible regeneration in humans. The adult zebrafish is able to regenerate efficiently after resecting nearly 20% of the ventricular apex. This process requires the concert activation of the epicardium and endocardium, as well as trans-differentiation of pre-existing cardiomyocytes that together replace the lost tissue. The molecular mechanisms involved in this activation process are not completely clarified. In this work, in order to investigate if the downregulation of these miRNAs (miRs) are linked with the activation of epicardium, the expressions of miR-133a, b and miR-1 during regeneration were analysed. qPCR analyses in whole-heart, or from distinct dissected epicardial cells comparing to regenerative clot (containing cardiomyocytes, fibroblasts and endocardial cells) by a laser-micro-dissector, have indicated that already at 24 h there is a downregulation of miRs: (1) miR-133a and miR-1 in the epicardium and (2) miR-133b and miR-1 in the regenerative clot. All the miRs remain downregulated until 7 days post-surgery. With the aim to visualize the activations of heart component in combination with miRs, we developed immunohistochemistry using antibodies directed against common markers in mammals as well as zebrafish: Wilms tumour 1 (WT1), a marker of epicardium; heat-shock protein 70 (HSP70), a chaperon activated during regeneration; and the Cardiac Troponin T (cTnT), a marker of differentiated cardiomyocytes. All these markers are directly or indirectly linked to the investigated miRs. WT1 and HSP70 strongly marked the regeneration site just at 2-3 days postventricular resection. In coherence, cTnT intensively marked the regenerative portion from 7 days onwards. miRs-1 and -133 (a,b) have been strongly involved in the activation of epicardium and regenerative clot during the regeneration process in zebrafish. This study can be a useful

Regulation of Injury-Induced Ovarian Regeneration by Activation of Oogonial Stem Cells.

PubMed

Erler, Piril; Sweeney, Alexandra; Monaghan, James R

2017-01-01

Some animals have the ability to generate large numbers of oocytes throughout life. This raises the question whether persistent adult germline stem cell populations drive continuous oogenesis and whether they are capable of mounting a regenerative response after injury. Here we demonstrate the presence of adult oogonial stem cells (OSCs) in the adult axolotl salamander ovary and show that ovarian injury induces OSC activation and functional regeneration of the ovaries to reproductive capability. Cells that have morphological similarities to germ cells were identified in the developing and adult ovaries via histological analysis. Genes involved in germ cell maintenance including Vasa, Oct4, Sox2, Nanog, Bmp15, Piwil1, Piwil2, Dazl, and Lhx8 were expressed in the presumptive OSCs. Colocalization of Vasa protein with H3 mitotic marker showed that both oogonial and spermatogonial adult stem cells were mitotically active. Providing evidence of stemness and viability of adult OSCs, enhanced green fluorescent protein (EGFP) adult OSCs grafted into white juvenile host gonads gave rise to EGFP OSCs, and oocytes. Last, the axolotl ovaries completely regenerated after partial ovariectomy injury. During regeneration, OSC activation resulted in rapid differentiation into new oocytes, which was demonstrated by Vasa + /BrdU + coexpression. Furthermore, follicle cell proliferation promoted follicle maturation during ovarian regeneration. Overall, these results show that adult oogenesis occurs via proliferation of endogenous OSCs in a tetrapod and mediates ovarian regeneration. This study lays the foundations to elucidate mechanisms of ovarian regeneration that will assist regenerative medicine in treating premature ovarian failure and reduced fertility. Stem Cells 2017;35:236-247. © 2016 AlphaMed Press.

Microwave-assisted regeneration of activated carbons loaded with pharmaceuticals.

PubMed

Ania, C O; Parra, J B; Menéndez, J A; Pis, J J

2007-08-01

The purpose of this work was to explore the application of microwaves for the regeneration of activated carbons spent with salicylic acid, a metabolite of a common analgesic frequently found in wastewater from the pharmaceutical industry. The exhausted carbon was treated in a quartz reactor by microwave irradiation at 2450 MHz at different temperatures and atmospheres, the regeneration efficiency being highly dependent on the operating conditions. Quantitative desorption of the pollutant was achieved at high temperature and oxidizing atmosphere, with regeneration efficiencies as high as 99% after six cycles. The stripping efficiency was superior to 95% at high temperatures and decreased at 450 degrees C. The incomplete desorption of the adsorbate at low temperature was further confirmed by the changes in the porosity observed by N2 and CO2 adsorption isotherms. Hence, micropores remain blocked which results in a reduction in loading capacities in successive cycles.

Chemical activation of Wnt/β-catenin signalling inhibits innervation and causes skeletal tissue malformations during axolotl limb regeneration.

PubMed

Wischin, Sabina; Castañeda-Patlán, Cristina; Robles-Flores, Martha; Chimal-Monroy, Jesús

2017-04-01

Limb regeneration involves several interrelated physiological processes in which a particular signalling pathway may play a variety of functions. Blocking the function of Wnt/β-catenin signalling during limb regeneration inhibits regeneration in axolotls (Ambystoma mexicanum). Limb development shares many features with limb regeneration, and Wnt/β-catenin activation has different effects depending on the developmental stage. The aim of this study was to evaluate whether Wnt/β-catenin signalling activation during axolotl limb regeneration has different effects when activated at different stages of regeneration. To evaluate this hypothesis, we treated amputated axolotls with a Wnt agonist chemical at different stages of limb regeneration. The results showed that limb regeneration was inhibited when the treatment began before blastema formation. Under these conditions, blastema formation was hindered, possibly due to the lack of innervation. On the other hand, when axolotls were treated after blastema formation and immediately before the onset of morphogenesis, we observed structural disorganization in skeletal formation. In conclusion, we found that limb regeneration was differentially affected depending on the stage at which the Wnt signalling pathway was activated. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemical in situ regeneration of granular activated carbon using a three-dimensional reactor.

PubMed

Sun, Hong; Liu, Zhigang; Wang, Ying; Li, Yansheng

2013-12-01

Electrochemical in situ regeneration of granular activated carbon (GAC) saturated with phenol was experimentally investigated using a three-dimensional electrode reactor with titanium filter electrode arrays. The feasibility of the electrochemical regeneration has been assessed by monitoring the regeneration efficiency and chemical oxygen demand (COD). The influence of the applied current, the effluent flow rate, and the effluent path of the electrochemical cell have been systematically studied. Under the optimum conditions, the regeneration efficiency of GAC could reach 94% in 2 hr, and no significant declination was observed after five-time continuous adsorption-regeneration cycles. The adsorption of organic pollutants was almost completely mineralized due to electrochemical oxidation, indicating that this regeneration process is much more potentially cost-effective for application. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Ozone regeneration of granular activated carbon for trihalomethane control.

PubMed

He, Xuexiang; Elkouz, Mark; Inyang, Mandu; Dickenson, Eric; Wert, Eric C

2017-03-15

Spatial and temporal variations of trihalomethanes (THMs) in distribution systems have challenged water treatment facilities to comply with disinfection byproduct rules. In this study, granular activated carbon (GAC) and modified GAC (i.e., Ag-GAC and TiO 2 -GAC) were used to treat chlorinated tap water containing CHCl 3 (15-21μg/L), CHBrCl 2 (13-16μg/L), CHBr 2 Cl (13-14μg/L), and CHBr 3 (3μg/L). Following breakthrough of dissolved organic carbon (DOC), GAC were regenerated using conventional and novel methods. GAC regeneration efficiency was assessed by measuring adsorptive (DOC, UV absorbance at 254nm, and THMs) and physical (surface area and pore volume) properties. Thermal regeneration resulted in a brief period of additional DOC adsorption (bed volume, BV, ∼6000), while ozone regeneration was ineffective regardless of the GAC type. THM adsorption was restored by either method (e.g., BV for ≥80% breakthrough, CHBr 3  ∼44,000>CHBr 2 Cl ∼35,000>CHBrCl 2  ∼31,000>CHCl 3  ∼7000). Cellular and attached adenosine triphosphate measurements illustrated the antimicrobial effects of Ag-GAC, which may have allowed for the extended THM adsorption compared to the other GAC types. The results illustrate that ozone regeneration may be a viable in-situ alternative for the adsorption of THMs during localized treatment in drinking water distribution systems. Published by Elsevier B.V.

The human ARF tumor suppressor senses blastema activity and suppresses epimorphic tissue regeneration

PubMed Central

Hesse, Robert G; Kouklis, Gayle K; Ahituv, Nadav; Pomerantz, Jason H

2015-01-01

The control of proliferation and differentiation by tumor suppressor genes suggests that evolution of divergent tumor suppressor repertoires could influence species’ regenerative capacity. To directly test that premise, we humanized the zebrafish p53 pathway by introducing regulatory and coding sequences of the human tumor suppressor ARF into the zebrafish genome. ARF was dormant during development, in uninjured adult fins, and during wound healing, but was highly expressed in the blastema during epimorphic fin regeneration after amputation. Regenerative, but not developmental signals resulted in binding of zebrafish E2f to the human ARF promoter and activated conserved ARF-dependent Tp53 functions. The context-dependent activation of ARF did not affect growth and development but inhibited regeneration, an unexpected distinct tumor suppressor response to regenerative versus developmental environments. The antagonistic pleiotropic characteristics of ARF as both tumor and regeneration suppressor imply that inducing epimorphic regeneration clinically would require modulation of ARF –p53 axis activation. DOI: http://dx.doi.org/10.7554/eLife.07702.001 PMID:26575287

Ecological restoration success is higher for natural regeneration than for active restoration in tropical forests

PubMed Central

Crouzeilles, Renato; Ferreira, Mariana S.; Chazdon, Robin L.; Lindenmayer, David B.; Sansevero, Jerônimo B. B.; Monteiro, Lara; Iribarrem, Alvaro; Latawiec, Agnieszka E.; Strassburg, Bernardo B. N.

2017-01-01

Is active restoration the best approach to achieve ecological restoration success (the return to a reference condition, that is, old-growth forest) when compared to natural regeneration in tropical forests? Our meta-analysis of 133 studies demonstrated that natural regeneration surpasses active restoration in achieving tropical forest restoration success for all three biodiversity groups (plants, birds, and invertebrates) and five measures of vegetation structure (cover, density, litter, biomass, and height) tested. Restoration success for biodiversity and vegetation structure was 34 to 56% and 19 to 56% higher in natural regeneration than in active restoration systems, respectively, after controlling for key biotic and abiotic factors (forest cover, precipitation, time elapsed since restoration started, and past disturbance). Biodiversity responses were based primarily on ecological metrics of abundance and species richness (74%), both of which take far less time to achieve restoration success than similarity and composition. This finding challenges the widely held notion that natural forest regeneration has limited conservation value and that active restoration should be the default ecological restoration strategy. The proposition that active restoration achieves greater restoration success than natural regeneration may have arisen because previous comparisons lacked controls for biotic and abiotic factors; we also did not find any difference between active restoration and natural regeneration outcomes for vegetation structure when we did not control for these factors. Future policy priorities should align the identified patterns of biophysical and ecological conditions where each or both restoration approaches are more successful, cost-effective, and compatible with socioeconomic incentives for tropical forest restoration. PMID:29134195

Ecological restoration success is higher for natural regeneration than for active restoration in tropical forests.

PubMed

Crouzeilles, Renato; Ferreira, Mariana S; Chazdon, Robin L; Lindenmayer, David B; Sansevero, Jerônimo B B; Monteiro, Lara; Iribarrem, Alvaro; Latawiec, Agnieszka E; Strassburg, Bernardo B N

2017-11-01

Is active restoration the best approach to achieve ecological restoration success (the return to a reference condition, that is, old-growth forest) when compared to natural regeneration in tropical forests? Our meta-analysis of 133 studies demonstrated that natural regeneration surpasses active restoration in achieving tropical forest restoration success for all three biodiversity groups (plants, birds, and invertebrates) and five measures of vegetation structure (cover, density, litter, biomass, and height) tested. Restoration success for biodiversity and vegetation structure was 34 to 56% and 19 to 56% higher in natural regeneration than in active restoration systems, respectively, after controlling for key biotic and abiotic factors (forest cover, precipitation, time elapsed since restoration started, and past disturbance). Biodiversity responses were based primarily on ecological metrics of abundance and species richness (74%), both of which take far less time to achieve restoration success than similarity and composition. This finding challenges the widely held notion that natural forest regeneration has limited conservation value and that active restoration should be the default ecological restoration strategy. The proposition that active restoration achieves greater restoration success than natural regeneration may have arisen because previous comparisons lacked controls for biotic and abiotic factors; we also did not find any difference between active restoration and natural regeneration outcomes for vegetation structure when we did not control for these factors. Future policy priorities should align the identified patterns of biophysical and ecological conditions where each or both restoration approaches are more successful, cost-effective, and compatible with socioeconomic incentives for tropical forest restoration.

Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration.

PubMed

Plikus, Maksim V; Mayer, Julie Ann; de la Cruz, Damon; Baker, Ruth E; Maini, Philip K; Maxson, Robert; Chuong, Cheng-Ming

2008-01-17

In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge are regulated by the surrounding microenvironment, or niche. The activation of such stem cells is cyclic, involving periodic beta-catenin activity. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/beta-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug

Geometric optimization of an active magnetic regenerative refrigerator via second-law analysis

NASA Astrophysics Data System (ADS)

Li, Peng; Gong, Maoqiong; Wu, Jianfeng

2008-11-01

Previous analyses [Z. Yan and J. Chen, J. Appl. Phys. 72, 1 (1992); J. Chen and Z. Yan, ibid., 84, 1791 (1998); Lin et al., Physica B 344, 147 (2004); Yang et al., ibid., 364, 33 (2005); Xia et al., ibid., 381, 246 (2006).] of irreversibilities in magnetic refrigerators overlooked several important losses that could be dominant in a real active magnetic regenerative refrigerator (AMRR). No quantitative expressions have been provided yet to estimate the corresponding entropy generations in real AMRRs. The important geometric parameters of AMRRs, such as the aspect ratio of the active magnetic regenerator and the refrigerant diameter, are still arbitrarily chosen. Expressions for calculating different types of entropy generations in the AMRR were derived and used to optimize the aspect ratio and the refrigerant diameter. An optimal coefficient of performance (15.54) was achieved at an aspect ratio of 6.39 and a refrigerant diameter of 1.1mm for our current system. Further study showed that the dissipative sources (e.g., the fluid friction and the unbalanced magnetic forces) in AMRRs, which were overlooked by previous investigations, could significantly contribute to entropy generations.

Catechins activate muscle stem cells by Myf5 induction and stimulate muscle regeneration.

PubMed

Kim, A Rum; Kim, Kyung Min; Byun, Mi Ran; Hwang, Jun-Ha; Park, Jung Il; Oh, Ho Taek; Kim, Hyo Kyeong; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

2017-07-22

Muscle weakness is one of the most common symptoms in aged individuals and increases risk of mortality. Thus, maintenance of muscle mass is important for inhibiting aging. In this study, we investigated the effect of catechins, polyphenol compounds in green tea, on muscle regeneration. We found that (-)-epicatechin gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) activate satellite cells by induction of Myf5 transcription factors. For satellite cell activation, Akt kinase was significantly induced after ECG treatment and ECG-induced satellite cell activation was blocked in the presence of Akt inhibitor. ECG also promotes myogenic differentiation through the induction of myogenic markers, including Myogenin and Muscle creatine kinase (MCK), in satellite and C2C12 myoblast cells. Finally, EGCG administration to mice significantly increased muscle fiber size for regeneration. Taken together, the results suggest that catechins stimulate muscle stem cell activation and differentiation for muscle regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Analyzing pERK Activation During Planarian Regeneration.

PubMed

Fraguas, Susanna; Umesono, Yoshihiko; Agata, Kiyokazu; Cebrià, Francesc

2017-01-01

Planarians are an ideal model in which to study stem cell-based regeneration. After amputation, planarian pluripotent stem cells surrounding the wound proliferate to produce the regenerative blastema, in which they differentiate into the missing tissues and structures. Recent independent studies in planarians have shown that Smed-egfr-3, a gene encoding a homologue of epidermal growth factor (EGF) receptors, and DjerkA, which encodes an extracellular signal-regulated kinase (ERK), may control cell differentiation and blastema growth. However, because these studies were carried in two different planarian species, the relationship between these two genes remains unclear. We have optimized anti-pERK immunostaining in Schmidtea mediterranea using the original protocol developed in Dugesia japonica. Both protocols are reported here as most laboratories worldwide work with one of these two species. Using this protocol we have determined that Smed-egfr-3 appears to be necessary for pERK activation during planarian regeneration.

Regeneration performance and carbon consumption of semi-coke and activated coke for SO₂ and NO removal.

PubMed

Ding, Song; Li, Yuran; Zhu, Tingyu; Guo, Yangyang

2015-08-01

To decrease the operating cost of flue gas purification technologies based on carbon-based materials, the adsorption and regeneration performance of low-price semi-coke and activated coke were compared for SO2 and NO removal in a simulated flue gas. The functional groups of the two adsorbents before and after regeneration were characterized by a Fourier transform infrared (FTIR) spectrometer, and were quantitatively assessed using temperature programmed desorption (TPD) coupled with FTIR and acid-base titration. The results show that semi-coke had higher adsorption capacity (16.2% for SO2 and 38.6% for NO) than activated coke because of its higher content of basic functional groups and lactones. After regeneration, the adsorption performance of semi-coke decreased because the number of active functional groups decreased and the micropores increased. Semi-coke had better regeneration performance than activated coke. Semi-coke had a larger SO2 recovery of 7.2% and smaller carbon consumption of 12% compared to activated coke. The semi-coke carbon-based adsorbent could be regenerated at lower temperatures to depress the carbon consumption, because the SO2 recovery was only reduced a small amount. Copyright © 2015. Published by Elsevier B.V.

Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

PubMed

Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

2016-02-01

The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. Copyright © 2015 Elsevier B.V. All rights reserved.

Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity.

PubMed

Chaillou, Thomas; Lanner, Johanna T

2016-12-01

Reduced oxygen (O 2 ) levels (hypoxia) are present during embryogenesis and exposure to altitude and in pathologic conditions. During embryogenesis, myogenic progenitor cells reside in a hypoxic microenvironment, which may regulate their activity. Satellite cells are myogenic progenitor cells localized in a local environment, suggesting that the O 2 level could affect their activity during muscle regeneration. In this review, we present the idea that O 2 levels regulate myogenesis and muscle regeneration, we elucidate the molecular mechanisms underlying myogenesis and muscle regeneration in hypoxia and depict therapeutic strategies using changes in O 2 levels to promote muscle regeneration. Severe hypoxia (≤1% O 2 ) appears detrimental for myogenic differentiation in vitro, whereas a 3-6% O 2 level could promote myogenesis. Hypoxia impairs the regenerative capacity of injured muscles. Although it remains to be explored, hypoxia may contribute to the muscle damage observed in patients with pathologies associated with hypoxia (chronic obstructive pulmonary disease, and peripheral arterial disease). Hypoxia affects satellite cell activity and myogenesis through mechanisms dependent and independent of hypoxia-inducible factor-1α. Finally, hyperbaric oxygen therapy and transplantation of hypoxia-conditioned myoblasts are beneficial procedures to enhance muscle regeneration in animals. These therapies may be clinically relevant to treatment of patients with severe muscle damage.-Chaillou, T. Lanner, J. T. Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity. © FASEB.

Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

NASA Astrophysics Data System (ADS)

Qu, Guangzhou; Liang, Dongli; Qu, Dong; Huang, Yimei; Li, Jie

2014-06-01

In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O3) regeneration) of saturated granular activated carbon (GAC) with pentachlorophenol (PCP) were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with O3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3 regeneration. O3 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cycles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after O3 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that O3 regeneration has a lower weight loss than DBD plasma regeneration.

In-situ regeneration of saturated granular activated carbon by an iron oxide nanocatalyst.

PubMed

Chiu, Chao-An; Hristovski, Kiril; Huling, Scott; Westerhoff, Paul

2013-03-15

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 (H(2)O(2)) 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Hair follicle stem cell proliferation, Akt and Wnt signaling activation in TPA-induced hair regeneration.

PubMed

Qiu, Weiming; Lei, Mingxing; Zhou, Ling; Bai, Xiufeng; Lai, Xiangdong; Yu, Yu; Yang, Tian; Lian, Xiaohua

2017-06-01

Regeneration of hair follicles relies on activation of hair follicle stem cells during telogen to anagen transition process in hair cycle. This process is rigorously controlled by intrinsic and environmental factors. 12-o-tetradecanoylphorbol-13-acetate (TPA), a tumor promoter, accelerates reentry of hair follicles into anagen phase. However, it is unclear that how TPA promotes the hair regeneration. In the present study, we topically applied TPA onto the dorsal skin of 2-month-old C57BL/6 female mice to examine the activity of hair follicle stem cells and alteration of signaling pathways during hair regeneration. We found that refractory telogen hair follicles entered anagen prematurely after TPA treatment, with the enhanced proliferation of CD34-positive hair follicle stem cells. Meanwhile, we observed Akt signaling was activated in epidermis, hair infundibulum, bulge and hair bulb, and Wnt signaling was also activated after hair follicle stem cells proliferation. Importantly, after overexpression of DKK1, a specific Wnt signaling inhibitor, the accelerated reentry of hair follicles into anagen induced by TPA was abolished. Our data indicated that TPA-induced hair follicle regeneration is associated with activation of Akt and Wnt/β-catenin signaling.

Supercritical Carbon Dioxide Regeneration of Activated Carbon Loaded with Contaminants from Rocky Mountain Arsenal Well Water.

DTIC Science & Technology

1982-05-01

PROCESSING COST OF ACTIVATED CHARCOAL REGENERATION BY SUPERCRITICAL CARBON DIOXIDE PROCESS ........................... 25 l IV-4 SENSITIVITY OF GAC...PROCESSING COSTS TO GAC WORKING CAPACITY ................................. 27 IV-5 ESTIMATED PROCESSING COST OF ACTIVATED CHARCOAL REGENERATION BY THERMAL...34 VI-2 COMPARISON OF THREE GRANULAR ACTIVATED CARBONS - SUPERCRITICAL CO2 REACTIVATION - GRANULAR CARBON ISOTHERMS - PHASE I RAW DATA

In vivo two-photon imaging of macrophage activities in skeletal muscle regeneration

NASA Astrophysics Data System (ADS)

Qin, Zhongya; Long, Yanyang; Sun, Qiqi; He, Sicong; Li, Xuesong; Chen, Congping; Wu, Zhenguo; Qu, Jianan Y.

2018-02-01

Macrophages are essential for the regeneration of skeletal muscle after injury. It has been demonstrated that depletion of macrophages results in delay of necrotic fiber phagocytosis and decreased size of regenerated myofibers. In this work, we developed a multi-modal two-photon microscope system for in vivo study of macrophage activities in the regenerative and fibrotic healing process of injured skeletal muscles. The system is capable to image the muscles based on the second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) signals simultaneously. The dynamic activities of macrophages and muscle satellite cells are recorded in different time windows post the muscle injury. Moreover, we found that infiltrating macrophages emitted strong autofluorescence in the injured skeletal muscle of mouse model, which has not been reported previously. The macrophage autofluorescence was characterized in both spectral and temporal domains. The information extracted from the autofluorescence signals may facilitate the understanding on the formation mechanisms and possible applications in biological research related to skeletal muscle regeneration.

Regeneration of spent powdered activated carbon saturated with inorganic ions by cavitation united with ion exchange method.

PubMed

Li, Gang; Gao, Hong; Li, Yansheng; Yang, Huixin

2011-06-01

Using ion exchange resin as transfer media, regenerate powdered activated carbon (PAC) adsorbed inorganic ions by cavitation to enhance the transfer; we studied how the regeneration time and the mass ratio of resin and PAC influence the regeneration rate respectively through re-adsorption. The result showed that the effective regeneration of PAC saturated with inorganic ions was above 90% using ion exchange resin as media and transfer carrier, the quantity of PAC did not reduced but activated in the process. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Regeneration of acid orange 7-exhausted granular activated carbons with microwave irradiation.

PubMed

Quan, Xie; Liu, Xitao; Bo, Longli; Chen, Shuo; Zhao, Yazhi; Cui, Xinyi

2004-12-01

An investigation was performed for the regeneration of three granular activated carbons (GACs) exhausted with acid orange 7 (AO7). The three GACs were made from different materials, i.e. coconut shells, almond nucleus and coal. The AO7 adsorption process was carried out in a continuous-flow adsorption column. After adsorption, the AO7-saturated GAC was dried at 120 degrees C, then regenerated in a quartz reactor by 2450 MHz microwave (MW) irradiation at 850 W for 5 min. The efficacy of this procedure was analyzed by determining the rates and amounts of AO7 adsorbed in successive adsorption-MW regeneration cycles. Effects of this regeneration on the structural properties, surface chemistry and the AO7 adsorption capacities of GAC samples were examined. It was found that after several adsorption-MW regeneration cycles, the adsorption rates and capacities of GACs could maintain relatively high levels, even higher than those of virgin GACs, as indicated by AO7 breakthrough curves and adsorption isotherms. The improvement of GAC adsorption properties resulted from the modification of pore size distribution and surface chemistry by MW irradiation.

Review of magnetic refrigeration system as alternative to conventional refrigeration system

NASA Astrophysics Data System (ADS)

Mezaal, N. A.; Osintsev, K. V.; Zhirgalova, T. B.

2017-10-01

The refrigeration system is one of the most important systems in industry. Developers are constantly seeking for how to avoid the damage to the environment. Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials, MCE warms as the magnetic moments of the atom are aligned by the application of a magnetic field. There are two types of magnetic phase changes that may occur at the Curie point: first order magnetic transition (FOMT) and second order magnetic transition (SOMT). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle), where the magnetic material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately magnetized and demagnetized. Many magnetic refrigeration prototypes with different designs and software models have been built in different parts of the world. In this paper, the authors try to shed light on the magnetic refrigeration and show its effectiveness compared with conventional refrigeration methods.

Development of the active magnetic regenerative refrigerator operating between 77 K and 20 K with the conduction cooled high temperature superconducting magnet

NASA Astrophysics Data System (ADS)

Park, Inmyong; Jeong, Sangkwon

2017-12-01

The experimental investigation of an active magnetic regenerative refrigerator (AMRR) operating between 77 K and 20 K is discussed in this paper, with detailed energy transfer analysis. A multi-layered active magnetic regenerator (AMR) is used, which consists of four different rare earth intermetallic compounds in the form of irregular powder. Numerical simulation confirms that the AMR can attain its target operating temperature range. Magnetic field alternation throughout the AMR is generated by a high temperature superconducting (HTS) magnet. The HTS magnet is cooled by a two stage Gifford-McMahon (GM) cryocooler. Helium gas was employed as a working fluid and its oscillating flow in the AMR is controlled in accordance with the magnetic field variation. The AMR is divided into two stages and each stage has a different mass flow rate as needed to achieve the desired cooling performance. The temperature variation of the AMR during the experiment is monitored by temperature sensors installed inside the AMR. The experimental results show that the AMRR is capable of achieving no-load temperature of 25.4 K while the warm end temperature is 77 K. The performance of the AMRR is analyzed by observing internal temperature variations at cyclic steady state. Furthermore, numerical estimation of the cooling capacity and the temperature variation of the AMR are examined and compared with the experimental results.

Muscle regeneration potential and satellite cell activation profile during recovery following hindlimb immobilization in mice.

PubMed

Guitart, Maria; Lloreta, Josep; Mañas-Garcia, Laura; Barreiro, Esther

2018-05-01

Reduced muscle activity leads to muscle atrophy and function loss in patients and animal models. Satellite cells (SCs) are postnatal muscle stem cells that play a pivotal role in skeletal muscle regeneration following injury. The regenerative potential, satellite cell numbers, and markers during recovery following immobilization of the hindlimb for 7 days were explored. In mice exposed to 7 days of hindlimb immobilization, in those exposed to recovery (7 days, splint removal), and in contralateral control muscles, muscle precursor cells were isolated from all hindlimb muscles (fluorescence-activated cell sorting, FACS) and SCs, and muscle regeneration were identified using immunofluorescence (gastrocnemius and soleus) and electron microscopy (EM, gastrocnemius). Expression of ki67, pax7, myoD, and myogenin was quantified (RT-PCR) from SC FACS yields. Body and grip strength were determined. Following 7 day hindlimb immobilization, a decline in SCs (FACS, immunofluorescence) was observed together with an upregulation of SC activation markers and signs of muscle regeneration including fusion to existing myofibers (EM). Recovery following hindlimb immobilization was characterized by a program of muscle regeneration events. Hindlimb immobilization induced a decline in SCs together with an upregulation of markers of SC activation, suggesting that fusion to existing myofibers takes place during unloading. Muscle recovery induced a significant rise in muscle precursor cells and regeneration events along with reduced SC activation expression markers and a concomitant rise in terminal muscle differentiation expression. These are novel findings of potential applicability for the treatment of disuse muscle atrophy, which is commonly associated with severe chronic and acute conditions. © 2017 Wiley Periodicals, Inc.

Changes in contractile activation characteristics of rat fast and slow skeletal muscle fibres during regeneration.

PubMed

Gregorevic, Paul; Plant, David R; Stupka, Nicole; Lynch, Gordon S

2004-07-15

Damaged skeletal muscle fibres are replaced with new contractile units via muscle regeneration. Regenerating muscle fibres synthesize functionally distinct isoforms of contractile and regulatory proteins but little is known of their functional properties during the regeneration process. An advantage of utilizing single muscle fibre preparations is that assessment of their function is based on the overall characteristics of the contractile apparatus and regulatory system and as such, these preparations are sensitive in revealing not only coarse, but also subtle functional differences between muscle fibres. We examined the Ca(2+)- and Sr(2+)-activated contractile characteristics of permeabilized fibres from rat fast-twitch (extensor digitorum longus) and slow-twitch (soleus) muscles at 7, 14 and 21 days following myotoxic injury, to test the hypothesis that fibres from regenerating fast and slow muscles have different functional characteristics to fibres from uninjured muscles. Regenerating muscle fibres had approximately 10% of the maximal force producing capacity (P(o)) of control (uninjured) fibres, and an altered sensitivity to Ca(2+) and Sr(2+) at 7 days post-injury. Increased force production and a shift in Ca(2+) sensitivity consistent with fibre maturation were observed during regeneration such that P(o) was restored to 36-45% of that in control fibres by 21 days, and sensitivity to Ca(2+) and Sr(2+) was similar to that of control (uninjured) fibres. The findings support the hypothesis that regenerating muscle fibres have different contractile activation characteristics compared with mature fibres, and that they adopt properties of mature fast- or slow-twitch muscle fibres in a progressive manner as the regeneration process is completed.

Ion channel signaling influences cellular proliferation and phagocyte activity during axolotl tail regeneration.

PubMed

Franklin, Brandon M; Voss, S Randal; Osborn, Jeffrey L

2017-08-01

Little is known about the potential for ion channels to regulate cellular behaviors during tissue regeneration. Here, we utilized an amphibian tail regeneration assay coupled with a chemical genetic screen to identify ion channel antagonists that altered critical cellular processes during regeneration. Inhibition of multiple ion channels either partially (anoctamin1/Tmem16a, anoctamin2/Tmem16b, K V 2.1, K V 2.2, L-type Ca V channels and H/K ATPases) or completely (GlyR, GABA A R, K V 1.5 and SERCA pumps) inhibited tail regeneration. Partial inhibition of tail regeneration by blocking the calcium activated chloride channels, anoctamin1&2, was associated with a reduction of cellular proliferation in tail muscle and mesenchymal regions. Inhibition of anoctamin 1/2 also altered the post-amputation transcriptional response of p44/42 MAPK signaling pathway genes, including decreased expression of erk1/erk2. We also found that complete inhibition via voltage gated K + channel blockade was associated with diminished phagocyte recruitment to the amputation site. The identification of H + pumps as required for axolotl tail regeneration supports findings in Xenopus and Planaria models, and more generally, the conservation of ion channels as regulators of tissue regeneration. This study provides a preliminary framework for an in-depth investigation of the mechanistic role of ion channels and their potential involvement in regulating cellular proliferation and other processes essential to wound healing, appendage regeneration, and tissue repair. Copyright © 2017 Elsevier B.V. All rights reserved.

IN-SITU REGENERATION OF GRANULAR ACTIVATED CARBON (GAC) USING FENTON'S REAGENTS

EPA Science Inventory

Fenton-dependent regeneration of granular activated carbon (GAC) initially saturated with one of several chlorinated aliphatic contaminants was studied in batch and continuous-flow reactors. Homogeneous and heterogeneous experiments were designed to investigate the effects of va...

Permanent magnet design for magnetic heat pumps using total cost minimization

NASA Astrophysics Data System (ADS)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Niknia, I.; Rowe, A.

2017-11-01

The active magnetic regenerator (AMR) is an attractive technology for efficient heat pumps and cooling systems. The costs associated with a permanent magnet for near room temperature applications are a central issue which must be solved for broad market implementation. To address this problem, we present a permanent magnet topology optimization to minimize the total cost of cooling using a thermoeconomic cost-rate balance coupled with an AMR model. A genetic algorithm identifies cost-minimizing magnet topologies. For a fixed temperature span of 15 K and 4.2 kg of gadolinium, the optimal magnet configuration provides 3.3 kW of cooling power with a second law efficiency (ηII) of 0.33 using 16.3 kg of permanent magnet material.

Thermally activated persulfate oxidation regeneration of NOM- and MTBE- spent granular activated carbon

EPA Science Inventory

Chemical oxidation is a developing technology used to regenerate contaminant-spent GAC. Chemical regeneration of GAC represents a viable option to thermal regeneration methods that are energy intensive resulting in significant consumption of fossil fuels and production of greenho...

Control of electrothermal heating during regeneration of activated carbon fiber cloth.

PubMed

Johnsen, David L; Mallouk, Kaitlin E; Rood, Mark J

2011-01-15

Electrothermal swing adsorption (ESA) of organic gases generated by industrial processes can reduce atmospheric emissions and allow for reuse of recovered product. Desorption energy efficiency can be improved through control of adsorbent heating, allowing for cost-effective separation and concentration of these gases for reuse. ESA experiments with an air stream containing 2000 ppm(v) isobutane and activated carbon fiber cloth (ACFC) were performed to evaluate regeneration energy consumption. Control logic based on temperature feedback achieved select temperature and power profiles during regeneration cycles while maintaining the ACFC's mean regeneration temperature (200 °C). Energy requirements for regeneration were independent of differences in temperature/power oscillations (1186-1237 kJ/mol of isobutane). ACFC was also heated to a ramped set-point, and the average absolute error between the actual and set-point temperatures was small (0.73%), demonstrating stable control as set-point temperatures vary, which is necessary for practical applications (e.g., higher temperatures for higher boiling point gases). Additional logic that increased the maximum power application at lower ACFC temperatures resulted in a 36% decrease in energy consumption. Implementing such control logic improves energy efficiency for separating and concentrating organic gases for post-desorption liquefaction of the organic gas for reuse.

Magnetic Resonance Imaging Allows the Evaluation of Tissue Damage and Regeneration in a Mouse Model of Critical Limb Ischemia.

PubMed

Zaccagnini, Germana; Palmisano, Anna; Canu, Tamara; Maimone, Biagina; Lo Russo, Francesco M; Ambrogi, Federico; Gaetano, Carlo; De Cobelli, Francesco; Del Maschio, Alessandro; Esposito, Antonio; Martelli, Fabio

2015-01-01

Magnetic resonance imaging (MRI) provides non-invasive, repetitive measures in the same individual, allowing the study of a physio-pathological event over time. In this study, we tested the performance of 7 Tesla multi-parametric MRI to monitor the dynamic changes of mouse skeletal muscle injury and regeneration upon acute ischemia induced by femoral artery dissection. T2-mapping (T2 relaxation time), diffusion-tensor imaging (Fractional Anisotropy) and perfusion by Dynamic Contrast-Enhanced MRI (K-trans) were measured and imaging results were correlated with histological morphometric analysis in both Gastrocnemius and Tibialis anterior muscles. We found that tissue damage positively correlated with T2-relaxation time, while myofiber regeneration and capillary density positively correlated with Fractional Anisotropy. Interestingly, K-trans positively correlated with capillary density. Accordingly, repeated MRI measurements between day 1 and day 28 after surgery in ischemic muscles showed that: 1) T2-relaxation time rapidly increased upon ischemia and then gradually declined, returning almost to basal level in the last phases of the regeneration process; 2) Fractional Anisotropy dropped upon ischemic damage induction and then recovered along with muscle regeneration and neoangiogenesis; 3) K-trans reached a minimum upon ischemia, then progressively recovered. Overall, Gastrocnemius and Tibialis anterior muscles displayed similar patterns of MRI parameters dynamic, with more marked responses and less variability in Tibialis anterior. We conclude that MRI provides quantitative information about both tissue damage after ischemia and the subsequent vascular and muscle regeneration, accounting for the differences between subjects and, within the same individual, between different muscles.

Pleiotrophin mediates hematopoietic regeneration via activation of RAS

PubMed Central

Himburg, Heather A.; Yan, Xiao; Doan, Phuong L.; Quarmyne, Mamle; Micewicz, Eva; McBride, William; Chao, Nelson J.; Slamon, Dennis J.; Chute, John P.

2014-01-01

Hematopoietic stem cells (HSCs) are highly susceptible to ionizing radiation–mediated death via induction of ROS, DNA double-strand breaks, and apoptotic pathways. The development of therapeutics capable of mitigating ionizing radiation–induced hematopoietic toxicity could benefit both victims of acute radiation sickness and patients undergoing hematopoietic cell transplantation. Unfortunately, therapies capable of accelerating hematopoietic reconstitution following lethal radiation exposure have remained elusive. Here, we found that systemic administration of pleiotrophin (PTN), a protein that is secreted by BM-derived endothelial cells, substantially increased the survival of mice following radiation exposure and after myeloablative BM transplantation. In both models, PTN increased survival by accelerating the recovery of BM hematopoietic stem and progenitor cells in vivo. PTN treatment promoted HSC regeneration via activation of the RAS pathway in mice that expressed protein tyrosine phosphatase receptor-zeta (PTPRZ), whereas PTN treatment did not induce RAS signaling in PTPRZ-deficient mice, suggesting that PTN-mediated activation of RAS was dependent upon signaling through PTPRZ. PTN strongly inhibited HSC cycling following irradiation, whereas RAS inhibition abrogated PTN-mediated induction of HSC quiescence, blocked PTN-mediated recovery of hematopoietic stem and progenitor cells, and abolished PTN-mediated survival of irradiated mice. These studies demonstrate the therapeutic potential of PTN to improve survival after myeloablation and suggest that PTN-mediated hematopoietic regeneration occurs in a RAS-dependent manner. PMID:25250571

Pleiotrophin mediates hematopoietic regeneration via activation of RAS.

PubMed

Himburg, Heather A; Yan, Xiao; Doan, Phuong L; Quarmyne, Mamle; Micewicz, Eva; McBride, William; Chao, Nelson J; Slamon, Dennis J; Chute, John P

2014-11-01

Hematopoietic stem cells (HSCs) are highly susceptible to ionizing radiation-mediated death via induction of ROS, DNA double-strand breaks, and apoptotic pathways. The development of therapeutics capable of mitigating ionizing radiation-induced hematopoietic toxicity could benefit both victims of acute radiation sickness and patients undergoing hematopoietic cell transplantation. Unfortunately, therapies capable of accelerating hematopoietic reconstitution following lethal radiation exposure have remained elusive. Here, we found that systemic administration of pleiotrophin (PTN), a protein that is secreted by BM-derived endothelial cells, substantially increased the survival of mice following radiation exposure and after myeloablative BM transplantation. In both models, PTN increased survival by accelerating the recovery of BM hematopoietic stem and progenitor cells in vivo. PTN treatment promoted HSC regeneration via activation of the RAS pathway in mice that expressed protein tyrosine phosphatase receptor-zeta (PTPRZ), whereas PTN treatment did not induce RAS signaling in PTPRZ-deficient mice, suggesting that PTN-mediated activation of RAS was dependent upon signaling through PTPRZ. PTN strongly inhibited HSC cycling following irradiation, whereas RAS inhibition abrogated PTN-mediated induction of HSC quiescence, blocked PTN-mediated recovery of hematopoietic stem and progenitor cells, and abolished PTN-mediated survival of irradiated mice. These studies demonstrate the therapeutic potential of PTN to improve survival after myeloablation and suggest that PTN-mediated hematopoietic regeneration occurs in a RAS-dependent manner.

Lightweight Magnetic Cooler With a Reversible Circulator

NASA Technical Reports Server (NTRS)

Chen, Weibo; McCormick, John

2011-01-01

A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin

Supercritical fluid regeneration of adsorbents

NASA Astrophysics Data System (ADS)

Defilippi, R. P.; Robey, R. J.

1983-05-01

The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

β2-Adrenoceptor is involved in connective tissue remodeling in regenerating muscles by decreasing the activity of MMP-9.

PubMed

Silva, Meiricris T; Nascimento, Tábata L; Pereira, Marcelo G; Siqueira, Adriane S; Brum, Patrícia C; Jaeger, Ruy G; Miyabara, Elen H

2016-07-01

We investigated the role of β2-adrenoceptors in the connective tissue remodeling of regenerating muscles from β2-adrenoceptor knockout (β2KO) mice. Tibialis anterior muscles from β2KO mice were cryolesioned and analyzed after 3, 10, and 21 days. Regenerating muscles from β2KO mice showed a significant increase in the area density of the connective tissue and in the amount of collagen at 10 days compared with wild-type (WT) mice. A greater increase occurred in the expression levels of collagen I, III, and IV in regenerating muscles from β2KO mice evaluated at 10 days compared with WT mice; this increase continued at 21 days, except for collagen III. Matrix metalloproteinase (MMP-2) activity increased to a similar extent in regenerating muscles from both β2KO and WT mice at 3 and 10 days. This was also the case for MMP-9 activity in regenerating muscles from both β2KO and WT mice at 3 days; however, at 10 days post-cryolesion, this activity returned to baseline levels only in WT mice. MMP-3 activity was unaltered in regenerating muscles at 10 days. mRNA levels of tumor necrosis factor-α increased in regenerating muscles from WT and β2KO mice at 3 days and, at 10 days post-cryolesion, returned to baseline only in WT mice. mRNA levels of interleukin-6 increased in muscles from WT mice at 3 days post-cryolesion and returned to baseline at 10 days post-cryolesion but were unchanged in β2KO mice. Our results suggest that the β2-adrenoceptor contributes to collagen remodeling during muscle regeneration by decreasing MMP-9 activity.

Leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent regeneration.

PubMed

Takayama, Kazuya; Muto, Akihiko; Kikuchi, Yutaka

2018-05-29

In animal regeneration, control of position-dependent cell proliferation is crucial for the complete restoration of patterned appendages in terms of both, shape and size. However, detailed mechanisms of this process are largely unknown. In this study, we identified leucine/glutamine and v-ATPase/lysosomal acidification, via mechanistic target of rapamycin complex 1 (mTORC1) activation, as effectors of amputation plane-dependent zebrafish caudal fin regeneration. mTORC1 activation, which functions in cell proliferation, was regulated by lysosomal acidification possibly via v-ATPase activity at 3 h post amputation (hpa). Inhibition of lysosomal acidification resulted in reduced growth factor-related gene expression and suppression of blastema formation at 24 and 48 hpa, respectively. Along the proximal-distal axis, position-dependent lysosomal acidification and mTORC1 activation were observed from 3 hpa. We also report that Slc7a5 (L-type amino acid transporter), whose gene expression is position-dependent, is necessary for mTORC1 activation upstream of lysosomal acidification during fin regeneration. Furthermore, treatment with leucine and glutamine, for both proximal and distal fin stumps, led to an up-regulation in cell proliferation via mTORC1 activation, indicating that leucine/glutamine signaling possesses the ability to change the position-dependent regeneration. Our findings reveal that leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent zebrafish fin regeneration.

Recovery comparisons--hot nitrogen Vs steam regeneration of toxic dichloromethane from activated carbon beds in oil sands process.

PubMed

Ramalingam, Shivaji G; Pré, Pascaline; Giraudet, Sylvain; Le Coq, Laurence; Le Cloirec, Pierre; Baudouin, Olivier; Déchelotte, Stéphane

2012-02-29

The regeneration experiments of dichloromethane from activated carbon bed had been carried out by both hot nitrogen and steam to evaluate the regeneration performance and the operating cost of the regeneration step. Factorial Experimental Design (FED) tool had been implemented to optimize the temperature of nitrogen and the superficial velocity of the nitrogen to achieve maximum regeneration at an optimized operating cost. All the experimental results of adsorption step, hot nitrogen and steam regeneration step had been validated by the simulation model PROSIM. The average error percentage between the simulation and experiment based on the mass of adsorption of dichloromethane was 2.6%. The average error percentages between the simulations and experiments based on the mass of dichloromethane regenerated by nitrogen regeneration and steam regeneration were 3 and 12%, respectively. From the experiments, it had been shown that both the hot nitrogen and steam regeneration had regenerated 84% of dichloromethane. But the choice of hot nitrogen or steam regeneration depends on the regeneration time, operating costs, and purity of dichloromethane regenerated. A thorough investigation had been made about the advantages and limitations of both the hot nitrogen and steam regeneration of dichloromethane. Copyright © 2011 Elsevier B.V. All rights reserved.

High throughput measurement of metabolism in planarians reveals activation of glycolysis during regeneration

PubMed Central

Osuma, Edie A.; Riggs, Daniel W.; Gibb, Andrew A.

2018-01-01

Abstract Planarians are outstanding models for studying mechanisms of regeneration; however, there are few methods to measure changes in their metabolism. Examining metabolism in planarians is important because the regenerative process is dependent on numerous integrated metabolic pathways, which provide the energy required for tissue repair as well as the ability to synthesize the cellular building blocks needed to form new tissue. Therefore, we standardized an extracellular flux analysis method to measure mitochondrial and glycolytic activity in live planarians during normal growth as well as during regeneration. Small, uninjured planarians showed higher rates of oxygen consumption compared with large planarians, with no difference in glycolytic activity; however, glycolysis increased during planarian regeneration. Exposure of planarians to koningic acid, a specific inhibitor of glyceraldehyde‐3‐phosphate dehydrogenase, completely abolished extracellular acidification with little effect on oxygen consumption, which suggests that the majority of glucose catabolized in planarians is fated for aerobic glycolysis. These studies describe a useful method for measuring respiration and glycolysis in planarians and provide data implicating changes in glucose metabolism in the regenerative response. PMID:29721328

Particle Size Effects on Fenton Regeneration of MTBE-spent Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of spent granular activated carbon (GAC) is a developing technology that may reduce water treatment costs. In this study, the effect of GAC particle size on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was evaluated. The GAC was...

Obesity Impairs Skeletal Muscle Regeneration Through Inhibition of AMPK.

PubMed

Fu, Xing; Zhu, Meijun; Zhang, Shuming; Foretz, Marc; Viollet, Benoit; Du, Min

2016-01-01

Obesity is increasing rapidly worldwide and is accompanied by many complications, including impaired muscle regeneration. The obese condition is known to inhibit AMPK activity in multiple tissues. We hypothesized that the loss of AMPK activity is a major reason for hampered muscle regeneration in obese subjects. We found that obesity inhibits AMPK activity in regenerating muscle, which was associated with impeded satellite cell activation and impaired muscle regeneration. To test the mediatory role of AMPKα1, we knocked out AMPKα1 and found that both proliferation and differentiation of satellite cells are reduced after injury and that muscle regeneration is severely impeded, reminiscent of hampered muscle regeneration seen in obese subjects. Transplanted satellite cells with AMPKα1 deficiency had severely impaired myogenic capacity in regenerating muscle fibers. We also found that attenuated muscle regeneration in obese mice is rescued by AICAR, a drug that specifically activates AMPK, but AICAR treatment failed to improve muscle regeneration in obese mice with satellite cell-specific AMPKα1 knockout, demonstrating the importance of AMPKα1 in satellite cell activation and muscle regeneration. In summary, AMPKα1 is a key mediator linking obesity and impaired muscle regeneration, providing a convenient drug target to facilitate muscle regeneration in obese populations. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

A two-step mechanism for stem cell activation during hair regeneration.

PubMed

Greco, Valentina; Chen, Ting; Rendl, Michael; Schober, Markus; Pasolli, H Amalia; Stokes, Nicole; Dela Cruz-Racelis, June; Fuchs, Elaine

2009-02-06

Hair follicles (HFs) undergo cyclic bouts of degeneration, rest, and regeneration. During rest (telogen), the hair germ (HG) appears as a small cell cluster between the slow-cycling bulge and dermal papilla (DP). Here we show that HG cells are derived from bulge stem cells (SCs) but become responsive quicker to DP-promoting signals. In vitro, HG cells also proliferate sooner but display shorter-lived potential than bulge cells. Molecularly, they more closely resemble activated bulge rather than transit-amplifying (matrix) cells. Transcriptional profiling reveals precocious activity of both HG and DP in late telogen, accompanied by Wnt signaling in HG and elevated FGFs and BMP inhibitors in DP. FGFs and BMP inhibitors participate with Wnts in exerting selective and potent stimuli to the HG both in vivo and in vitro. Our findings suggest a model where HG cells fuel initial steps in hair regeneration, while the bulge is the engine maintaining the process.

Self-powered suspension criterion and energy regeneration implementation scheme of motor-driven active suspension

NASA Astrophysics Data System (ADS)

Yan, Shuai; Sun, Weichao

2017-09-01

Active suspension systems have advantages on mitigating the effects of vehicle vibration caused by road roughness, which are one of the most important component parts in influencing the performances of vehicles. However, high amount of energy consumption restricts the application of active suspension systems. From the point of energy saving, this paper presents a self-powered criterion of the active suspension system to judge whether a motor-driven suspension can be self-powered or not, and then a motor parameter condition is developed as a reference to design a self-powered suspension. An energy regeneration implementation scheme is subsequently proposed to make the active suspension which has the potential to be self-powered achieve energy-saving target in the real application. In this implementation scheme, operating electric circuits are designed based on different working status of the actuator and power source and it is realizable to accumulate energy from road vibration and supply energy to the actuator by switching corresponding electric circuits. To apply the self-powered suspension criterion and energy regeneration implementation scheme, an active suspension system is designed with a constrained H∞ controller and calculation results indicate that it has the capability to be self-powered. Simulation results show that the performances of the self-powered active suspension are nearly the same as those of the active suspension with an external energy source and can achieve energy regeneration at the same time.

A nonventing cooling system for space environment extravehicular activity, using radiation and regenerable thermal storage

NASA Technical Reports Server (NTRS)

Bayes, Stephen A.; Trevino, Luis A.; Dinsmore, Craig E.

1988-01-01

This paper outlines the selection, design, and testing of a prototype nonventing regenerable astronaut cooling system for extravehicular activity space suit applications, for mission durations of four hours or greater. The selected system consists of the following key elements: a radiator assembly which serves as the exterior shell of the portable life support subsystem backpack; a layer of phase change thermal storage material, n-hexadecane paraffin, which acts as a regenerable thermal capacitor; a thermoelectric heat pump; and an automatic temperature control system. The capability for regeneration of thermal storage capacity with and without the aid of electric power is provided.

Superheated water pretreatment combined with CO2 activation/regeneration of the exhausted activated carbon used in the treatment of industrial wastewater.

PubMed

Xiao, Jin; Yu, Bailie; Zhong, Qifan; Yuan, Jie; Yao, Zhen; Zhang, Liuyun

2017-10-01

This paper examines a novel method of regenerating saturated activated carbon after adsorption of complex phenolic, polycyclic aromatic hydrocarbons with low energy consumption by using superheated water pretreatment combined with CO 2 activation. The effects of the temperature of the superheated water, liquid-solid ratio, soaking time, activation temperature, activation time, and CO 2 flow rate of regeneration and adsorption of coal-powdered activated carbon (CPAC) were studied. The results show that the adsorption capacity of iodine values on CPAC recovers to 102.25% of the fresh activated carbon, and the recovery rate is 79.8% under optimal experimental conditions. The adsorption model and adsorption kinetics of methylene blue on regenerated activated carbon (RAC) showed that the adsorption process was in accordance with the Langmuir model and the pseudo-second-order kinetics model. Furthermore, the internal diffusion process was the main controlling step. The surface properties, Brunauer-Emmett-Teller (BET) surface area, and pore size distribution were characterized by Fourier transform infrared spectroscopy (FT-IR) and BET, which show that the RAC possesses more oxygen-containing functional groups with a specific surface area of 763.39 m 2 g -1 and a total pore volume of 0.3039 cm 3 g -1 . Micropores account for 79.8% and mesopores account for 20.2%.

Cartilage regeneration for treatment of osteoarthritis: a paradigm for nonsurgical intervention

PubMed Central

Sabaawy, Hatem E.

2015-01-01

Osteoarthritis (OA) is associated with articular cartilage abnormalities and affects people of older age: preventative or therapeutic treatment measures for OA and related articular cartilage disorders remain challenging. In this perspective review, we have integrated multiple biological, morphological, developmental, stem cell and homeostasis concepts of articular cartilage to develop a paradigm for cartilage regeneration. OA is conceptually defined as an injury of cartilage that initiates chondrocyte activation, expression of proteases and growth factor release from the matrix. This regenerative process results in the local activation of inflammatory response genes in cartilage without migration of inflammatory cells or angiogenesis. The end results are catabolic and anabolic responses, and it is the balance between these two outcomes that controls remodelling of the matrix and regeneration. A tantalizing clinical clue for cartilage regrowth in OA joints has been observed in surgically created joint distraction. We hypothesize that cartilage growth in these distracted joints may have a biological connection with the size of organs and regeneration. Therefore we propose a novel, practical and nonsurgical intervention to validate the role of distraction in cartilage regeneration in OA. The approach permits normal wake-up activity while during sleep; the index knee is subjected to distraction with a pull traction device. Comparison of follow-up magnetic resonance imaging (MRI) at 3 and 6 months of therapy to those taken before therapy will provide much-needed objective evidence for the use of this mode of therapy for OA. We suggest that the paradigm presented here merits investigation for treatment of OA in knee joints. PMID:26029269

RED CELL STROMA PROTEIN RICH IN VITAMIN B12 DURING ACTIVE REGENERATION

PubMed Central

Whipple, G. H.; Robscheit-Robbins, F. S.; Bale, W. F.

1955-01-01

During active blood regeneration in anemia in dogs an increase occurs in the stroma protein of the red cells. When vitamin B12 with radioactive cobalt is given at the start of this blood regeneration one finds concentration of labeled B 12 in the stroma protein but not in the hemoglobin. After the acute phase of red cell regeneration is ended the concentration of B12 in stroma protein falls rapidly to very low levels within 2 weeks. Subsequent episodes of red blood cell regeneration seems not to cause remobilization of radioactive cobalt into red cells from other body stores. It appears that the vitamin B12 is a factor of importance in the first steps of stroma protein formation in the first few days of the life of the red cell in the dog. This response in dogs and the response in pernicious anemia to vitamin B12 may have some points in common. Distribution of the B12-radioactive cobalt in the organs and tissues at autopsy has been recorded. Some very suggestive localizations were noted and some variation 1 week and 7 weeks after B12 injections. Radioactive cobalt escapes in the urine during the weeks following B12 injections. PMID:13271685

Temperature control during regeneration of activated carbon fiber cloth with resistance-feedback.

PubMed

Johnsen, David L; Rood, Mark J

2012-10-16

Electrothermal swing adsorption (ESA) of organic compounds from gas streams with activated carbon fiber cloth (ACFC) reduces emissions to the atmosphere and recovers feedstock for reuse. Local temperature measurement (e.g., with a thermocouple) is typically used to monitor/control adsorbent regeneration cycles. Remote electrical resistance measurement is evaluated here as an alternative to local temperature measurement. ACFC resistance that was modeled based on its physical properties was within 10.5% of the measured resistance values during electrothermal heating. Resistance control was developed based on this measured relationship and used to control temperature to within 2.3% of regeneration set-point temperatures. Isobutane-laden adsorbent was then heated with resistance control. After 2 min of heating, the temperature of the adsorbent with isobutane was 13% less than the adsorbent without isobutane. This difference decreased to 2.1% after 9 min of heating, showing desorption of isobutane. An ACFC cartridge was also heated to 175 °C for 900 cycles with its resistance and adsorption capacity values remaining within 3% and 2%, respectively. This new method to control regeneration power application based on rapid sensing of the adsorbent's resistance removes the need for direct-contact temperature sensors providing a simple, cost-efficient, and long-term regeneration technique for ESA systems.

The CXCR4/SDF1 Axis Improves Muscle Regeneration Through MMP-10 Activity

PubMed Central

Bobadilla, Miriam; Sainz, Neira; Abizanda, Gloria; Orbe, Josune; Rodriguez, José Antonio; Páramo, José Antonio; Prósper, Felipe

2014-01-01

The CXCR4/SDF1 axis participates in various cellular processes, including cell migration, which is essential for skeletal muscle repair. Although increasing evidence has confirmed the role of CXCR4/SDF1 in embryonic muscle development, the function of this pathway during adult myogenesis remains to be fully elucidated. In addition, a role for CXCR4 signaling in muscle maintenance and repair has only recently emerged. Here, we have demonstrated that CXCR4 and stromal cell-derived factor-1 (SDF1) are up-regulated in injured muscle, suggesting their involvement in the repair process. In addition, we found that notexin-damaged muscles showed delayed muscle regeneration on treatment with CXCR4 agonist (AMD3100). Accordingly, small-interfering RNA-mediated silencing of SDF1 or CXCR4 in injured muscles impaired muscle regeneration, whereas the addition of SDF1 ligand accelerated repair. Furthermore, we identified that CXCR4/SDF1-regulated muscle repair was dependent on matrix metalloproteinase-10 (MMP-10) activity. Thus, our findings support a model in which MMP-10 activity modulates CXCR4/SDF1 signaling, which is essential for efficient skeletal muscle regeneration. PMID:24548137

Localized epigenetic silencing of a damage-activated WNT enhancer limits regeneration in mature Drosophila imaginal discs

PubMed Central

Harris, Robin E; Setiawan, Linda; Saul, Josh; Hariharan, Iswar K

2016-01-01

Many organisms lose the capacity to regenerate damaged tissues as they mature. Damaged Drosophila imaginal discs regenerate efficiently early in the third larval instar (L3) but progressively lose this ability. This correlates with reduced damage-responsive expression of multiple genes, including the WNT genes wingless (wg) and Wnt6. We demonstrate that damage-responsive expression of both genes requires a bipartite enhancer whose activity declines during L3. Within this enhancer, a damage-responsive module stays active throughout L3, while an adjacent silencing element nucleates increasing levels of epigenetic silencing restricted to this enhancer. Cas9-mediated deletion of the silencing element alleviates WNT repression, but is, in itself, insufficient to promote regeneration. However, directing Myc expression to the blastema overcomes repression of multiple genes, including wg, and restores cellular responses necessary for regeneration. Localized epigenetic silencing of damage-responsive enhancers can therefore restrict regenerative capacity in maturing organisms without compromising gene functions regulated by developmental signals. DOI: http://dx.doi.org/10.7554/eLife.11588.001 PMID:26840050

Fenton-driven regeneration of MTBE-spent granular activated carbon - Effects of particle size and Iron Amendment Procedures

EPA Science Inventory

Fenton-driven regeneration of spent granular activated carbon (GAC) is a technology being developed to regenerate organic contaminant-spent GAC. Here, the effect of GAC particle size (>2 mm to <0.35 mm) on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was ev...

Shp2–Mitogen-Activated Protein Kinase Signaling Drives Proliferation during Zebrafish Embryo Caudal Fin Fold Regeneration

PubMed Central

Hale, Alexander James

2017-01-01

ABSTRACT Regeneration of the zebrafish caudal fin following amputation occurs through wound healing, followed by formation of a blastema, which produces cells to replace the lost tissue in the final phase of regenerative outgrowth. We show that ptpn11a−/− ptpn11b−/− zebrafish embryos, lacking functional Shp2, fail to regenerate their caudal fin folds. Rescue experiments indicated that Shp2a has a functional signaling role, requiring its catalytic activity and SH2 domains but not the two C-terminal tyrosine phosphorylation sites. Surprisingly, expression of Shp2a variants with increased and reduced catalytic activity, respectively, rescued caudal fin fold regeneration to similar extents. Expression of mmp9 and junbb, indicative of formation of the wound epidermis and distal blastema, respectively, suggested that these processes occurred in ptpn11a−/− ptpn11b−/− zebrafish embryos. However, cell proliferation and MAPK phosphorylation were reduced. Pharmacological inhibition of MEK1 in wild-type zebrafish embryos phenocopied loss of Shp2. Our results suggest an essential role for Shp2a–mitogen-activated protein kinase (MAPK) signaling in promoting cell proliferation during zebrafish embryo caudal fin fold regeneration. PMID:29203641

Effect of ground skidding on oak advance regeneration

Treesearch

Jeffrey W. Stringer

2006-01-01

Vigorous advance regeneration is required to naturally regenerate oaks. However, a reduction in the number of advance regeneration stems from harvesting activities could be an important factor in determining successful oak regeneration. This study assessed the harvest survivability of advance regeneration of oak (Quercus spp.) and co-occurring...

Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the Central Nervous System Following Neural Injury (Addendum)

DTIC Science & Technology

2016-03-01

AD_________________ Award Number: W81XWH-12-1-0051 TITLE: Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the...Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the Central Nervous System Following Neural Injury 5a. CONTRACT NUMBER...incapable of axon regeneration . There are currently two principal concepts that form the basis of our understanding of the inability of the mature

Spinal cord regeneration in Xenopus tadpoles proceeds through activation of Sox2-positive cells

PubMed Central

2012-01-01

Background In contrast to mammals, amphibians, such as adult urodeles (for example, newts) and anuran larvae (for example, Xenopus) can regenerate their spinal cord after injury. However, the cellular and molecular mechanisms involved in this process are still poorly understood. Results Here, we report that tail amputation results in a global increase of Sox2 levels and proliferation of Sox2+ cells. Overexpression of a dominant negative form of Sox2 diminished proliferation of spinal cord resident cells affecting tail regeneration after amputation, suggesting that spinal cord regeneration is crucial for the whole process. After spinal cord transection, Sox2+ cells are found in the ablation gap forming aggregates. Furthermore, Sox2 levels correlated with regenerative capabilities during metamorphosis, observing a decrease in Sox2 levels at non-regenerative stages. Conclusions Sox2+ cells contribute to the regeneration of spinal cord after tail amputation and transection. Sox2 levels decreases during metamorphosis concomitantly with the lost of regenerative capabilities. Our results lead to a working hypothesis in which spinal cord damage activates proliferation and/or migration of Sox2+ cells, thus allowing regeneration of the spinal cord after tail amputation or reconstitution of the ependymal epithelium after spinal cord transection. PMID:22537391

Expression of an Activated Integrin Promotes Long-Distance Sensory Axon Regeneration in the Spinal Cord

PubMed Central

Cheah, Menghon; Chew, Daniel J.; Moloney, Elizabeth B.; Verhaagen, Joost; Fässler, Reinhard

2016-01-01

After CNS injury, axon regeneration is blocked by an inhibitory environment consisting of the highly upregulated tenascin-C and chondroitin sulfate proteoglycans (CSPGs). Tenascin-C promotes growth of axons if they express a tenascin-binding integrin, particularly α9β1. Additionally, integrins can be inactivated by CSPGs, and this inhibition can be overcome by the presence of a β1-binding integrin activator, kindlin-1. We examined the synergistic effect of α9 integrin and kindlin-1 on sensory axon regeneration in adult rat spinal cord after dorsal root crush and adeno-associated virus transgene expression in dorsal root ganglia. After 12 weeks, axons from C6–C7 dorsal root ganglia regenerated through the tenascin-C-rich dorsal root entry zone into the dorsal column up to C1 level and above (>25 mm axon length) through a normal pathway. Animals also showed anatomical and electrophysiological evidence of reconnection to the dorsal horn and behavioral recovery in mechanical pressure, thermal pain, and ladder-walking tasks. Expression of α9 integrin or kindlin-1 alone promoted much less regeneration and recovery. SIGNIFICANCE STATEMENT The study demonstrates that long-distance sensory axon regeneration over a normal pathway and with sensory and sensory–motor recovery can be achieved. This was achieved by expressing an integrin that recognizes tenascin-C, one of the components of glial scar tissue, and an integrin activator. This enabled extensive long-distance (>25 mm) regeneration of both myelinated and unmyelinated sensory axons with topographically correct connections in the spinal cord. The extent of growth and recovery we have seen would probably be clinically significant. Restoration of sensation to hands, perineum, and genitalia would be a significant improvement for a spinal cord-injured patient. PMID:27383601

The influence of activated carbon surface properties on the adsorption of the herbicide molinate and the bio-regeneration of the adsorbent.

PubMed

Coelho, Cláudia; Oliveira, Ana Sofia; Pereira, Manuel Fernando R; Nunes, Olga C

2006-11-16

In the present study, the effect of the textural and surface chemistry properties of the activated carbon were evaluated in a combined treatment system to remove the herbicide molinate from waters. The process consists of an initial adsorption step followed by the bio-regeneration of the activated carbon through the utilization of a defined bacterial mixed culture (DC), previously described as able to mineralize molinate. Molinate adsorption and partial bio-regeneration was favoured with activated carbons with larger pores, consisting mainly of meso and macropores. In order to study the effect of different surface chemical characteristics while maintaining the original textural properties, a commercial activated carbon was submitted to thermal and nitric acid treatments. The thermal treatment improved the molinate adsorption capacity of activated carbon. However, the bio-regeneration of the nitric acid oxidised activated carbon was slightly higher. With all the activated carbon materials used it was observed that the biological consumption of molinate present in the liquid phase displaced the equilibrium towards the activated carbon partial regeneration.

NT-3 promotes proprioceptive axon regeneration when combined with activation of the mTor intrinsic growth pathway but not with reduction of myelin extrinsic inhibitors

PubMed Central

Liu, Yingpeng; Kelamangalath, Lakshmi; Kim, Hyukmin; Han, Seung Baek; Tang, Xiaoqing; Zhai, Jinbin; Hong, Jee W; Lin, Shen; Son, Young-Jin; Smith, George M.

2016-01-01

Although previous studies have identified several strategies to stimulate regeneration of CNS axons, extensive regeneration and functional recovery have remained a major challenge, particularly for large diameter myelinated axons. Within the CNS, myelin is thought to inhibit axon regeneration, while modulating activity of the mTOR pathway promotes regeneration of injured axons. In this study, we examined NT-3 mediated regeneration of sensory axons through the dorsal root entry zone in a triple knockout of myelin inhibitory proteins or after activation of mTOR using a constitutively active (ca) Rheb in DRG neurons to determine the influence of environmental inhibitory or activation of intrinsic growth pathways could enhance NT-3-mediate regeneration. Loss of myelin inhibitory proteins showed modest enhancement of sensory axon regeneration. In mTOR studies, we found a dramatic age related decrease in the mTOR activation as determined by phosphorylation of the downstream marker S6 ribosomal subunit. Expression of caRheb within adult DRG neurons in vitro increased S6 phosphorylation and doubled the overall length of neurite outgrowth, which was reversed in the presence of rapamycin. In adult female rats, combined expression of caRheb in DRG neurons and NT-3 within the spinal cord increased regeneration of sensory axons almost 3 fold when compared to NT-3 alone. Proprioceptive assessment using a grid runway indicates functionally significant regeneration of large-diameter myelinated sensory afferents. Our results indicate that caRheb-induced increase in mTOR activation enhances neurotrophin-3 induced regeneration of large-diameter myelinated axons. PMID:27264357

In-Situ Regeneration of Saturated Granular Activated Carbon by an Iron Oxide Nanocatalyst

EPA Science Inventory

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 con...

Macrophages are necessary for epimorphic regeneration in African spiny mice.

PubMed

Simkin, Jennifer; Gawriluk, Thomas R; Gensel, John C; Seifert, Ashley W

2017-05-16

How the immune system affects tissue regeneration is not well understood. In this study, we used an emerging mammalian model of epimorphic regeneration, the African spiny mouse, to examine cell-based inflammation and tested the hypothesis that macrophages are necessary for regeneration. By directly comparing inflammatory cell activation in a 4 mm ear injury during regeneration ( Acomys cahirinus ) and scarring ( Mus musculus ), we found that both species exhibited an acute inflammatory response, with scarring characterized by stronger myeloperoxidase activity. In contrast, ROS production was stronger and more persistent during regeneration. By depleting macrophages during injury, we demonstrate a functional requirement for these cells to stimulate regeneration. Importantly, the spatial distribution of activated macrophage subtypes was unique during regeneration with pro-inflammatory macrophages failing to infiltrate the regeneration blastema. Together, our results demonstrate an essential role for inflammatory cells to regulate a regenerative response.

Proresolving Nanomedicines Activate Bone Regeneration in Periodontitis

PubMed Central

Hasturk, H.; Kantarci, A.; Freire, M.O.; Nguyen, D.; Dalli, J.; Serhan, C.N.

2015-01-01

Therapies to reverse tissue damage from osteolytic inflammatory diseases are limited by the inability of current tissue-engineering procedures to restore lost hard and soft tissues. There is a critical need for new therapeutics in regeneration. In addition to scaffolds, cells, and soluble mediators necessary for tissue engineering, control of endogenous inflammation is an absolute requirement for success. Although significant progress has been made in understanding natural resolution of inflammation pathways to limit uncontrolled inflammation in disease, harnessing the biomimetic properties of proresolving lipid mediators has not been demonstrated. Here, we report the use of nano-proresolving medicines (NPRM) containing a novel lipoxin analog (benzo-lipoxin A4, bLXA4) to promote regeneration of hard and soft tissues irreversibly lost to periodontitis in the Hanford miniature pig. In this proof-of-principle experiment, NPRM-bLXA4 dramatically reduced inflammatory cell infiltrate into chronic periodontal disease sites treated surgically and dramatically increased new bone formation and regeneration of the periodontal organ. These findings indicate that NPRM-bLXA4 is a mimetic of endogenous resolving mechanisms with potent bioactions that offers a new therapeutic tissue-engineering approach for the treatment of chronic osteolytic inflammatory diseases. PMID:25389003

Microwave-assisted regeneration of synthetic zeolite used in tritium removal systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, M.; Takayama, S.; Sano, S.

The regeneration process using synthetic honeycomb type 5A zeolite under microwave irradiation was experimentally investigated using a single-mode cavity at 2.46 GHz. In order to investigate the effect of electromagnetic fields, inductive heating by a magnetic field was applied to synthetic zeolite containing water. Because the microwave energy absorbed in the sample was less than 15 W, the zeolite sample was only heated to a temperature of 71 C. degrees. Water desorption was observed based on the increased temperature of the zeolite sample and the thermogravimetric curve that indicated a single step phenomenon. As a result, the regeneration process ofmore » zeolite was not complete over a period of 6000 s. A comparison of dielectric heating by an electric field with inductive heating by a magnetic field showed that the regeneration process by microwave irradiation was particularly beneficial in dielectric heating. (authors)« less

Fenton-Driven Chemical Regeneration of MTBE-Spent Granular Activated Carbon -- A Pilot Study

EPA Science Inventory

MTBE-spent granular activated carbon (GAC) underwent 3 adsorption/oxidation cycles. Pilot-scale columns were intermittently placed on-line at a ground water pump and treat facility, saturated with MTBE, and regenerated with H2O2 under different chemical, physical, and operational...

Regenerating Fish Optic Nerves and a Regeneration-Like Response in Injured Optic Nerves of Adult Rabbits

NASA Astrophysics Data System (ADS)

Schwartz, M.; Belkin, M.; Harel, A.; Solomon, A.; Lavie, V.; Hadani, M.; Rachailovich, I.; Stein-Izsak, C.

1985-05-01

Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a ``wrap-around'' implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.

Microwave mode shifting antenna system for regenerating particulate filters

DOEpatents

Gonze, Eugene V [Pinckney, MI; Kirby, Kevin W [Calabasas Hills, CA; Phelps, Amanda [Malibu, CA; Gregoire, Daniel J [Thousand Oaks, CA

2011-04-26

A regeneration system comprises a particulate matter (PM) filter including a microwave energy absorbing surface, and an antenna system comprising N antennas and an antenna driver module that sequentially drives the antenna system in a plurality of transverse modes of the antenna system to heat selected portions of the microwave absorbing surface to regenerate the PM filter, where N is an integer greater than one. The transverse modes may include transverse electric (TE) and/or transverse magnetic (TM) modes.

Modulation of tissue repair by regeneration enhancer elements.

PubMed

Kang, Junsu; Hu, Jianxin; Karra, Ravi; Dickson, Amy L; Tornini, Valerie A; Nachtrab, Gregory; Gemberling, Matthew; Goldman, Joseph A; Black, Brian L; Poss, Kenneth D

2016-04-14

How tissue regeneration programs are triggered by injury has received limited research attention. Here we investigate the existence of enhancer regulatory elements that are activated in regenerating tissue. Transcriptomic analyses reveal that leptin b (lepb) is highly induced in regenerating hearts and fins of zebrafish. Epigenetic profiling identified a short DNA sequence element upstream and distal to lepb that acquires open chromatin marks during regeneration and enables injury-dependent expression from minimal promoters. This element could activate expression in injured neonatal mouse tissues and was divisible into tissue-specific modules sufficient for expression in regenerating zebrafish fins or hearts. Simple enhancer-effector transgenes employing lepb-linked sequences upstream of pro- or anti-regenerative factors controlled the efficacy of regeneration in zebrafish. Our findings provide evidence for 'tissue regeneration enhancer elements' (TREEs) that trigger gene expression in injury sites and can be engineered to modulate the regenerative potential of vertebrate organs.

HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver.

PubMed

Ding, Bi-Sen; Liu, Catherine H; Sun, Yue; Chen, Yutian; Swendeman, Steven L; Jung, Bongnam; Chavez, Deebly; Cao, Zhongwei; Christoffersen, Christina; Nielsen, Lars Bo; Schwab, Susan R; Rafii, Shahin; Hla, Timothy

2016-12-22

Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S1P 1 ) by its natural ligand bound to HDL (HDL-S1P) induces liver regeneration and curtails fibrosis. In mice lacking HDL-S1P, liver regeneration after partial hepatectomy was impeded and associated with aberrant vascular remodeling, thrombosis and peri-sinusoidal fibrosis. Notably, this "maladaptive repair" phenotype was recapitulated in mice that lack S1P 1 in the endothelium. Reciprocally, enhanced plasma levels of HDL-S1P or administration of SEW2871, a pharmacological agonist specific for S1P 1 enhanced regeneration of metabolically functional vasculature and alleviated fibrosis in mouse chronic injury and cholestasis models. This study shows that natural and pharmacological ligands modulate endothelial S1P 1 to stimulate liver regeneration and inhibit fibrosis, suggesting that activation of this pathway may be a novel therapeutic strategy for liver fibrosis.

Inhibition of H3K27me3 Histone Demethylase Activity Prevents the Proliferative Regeneration of Zebrafish Lateral Line Neuromasts

PubMed Central

Bao, Beier; He, Yingzi; Tang, Dongmei; Li, Wenyan; Li, Huawei

2017-01-01

The H3K27 demethylases are involved in a variety of biological processes, including cell differentiation, proliferation, and cell death by regulating transcriptional activity. However, the function of H3K27 demethylation in the field of hearing research is poorly understood. Here, we investigated the role of H3K27me3 histone demethylase activity in hair cell regeneration using an in vivo animal model. Our data showed that pharmacologic inhibition of H3K27 demethylase activity with the specific small-molecule inhibitor GSK-J4 decreased the number of regenerated hair cells in response to neomycin damage. Furthermore, inhibition of H3K27me3 histone demethylase activity dramatically suppressed cell proliferation and activated caspase-3 levels in the regenerating neuromasts of the zebrafish lateral line. GSK-J4 administration also increased the expression of p21 and p27 in neuromast cells and inhibited the ERK signaling pathway. Collectively, our findings indicate that H3K27me3 demethylation is a key epigenetic regulator in the process of hair cell regeneration in zebrafish and suggest that H3K27me3 histone demethylase activity might be a novel therapeutic target for the treatment of hearing loss. PMID:28348517

Hindlimb suspension reduces muscle regeneration

NASA Technical Reports Server (NTRS)

Mozdziak, P. E.; Truong, Q.; Macius, A.; Schultz, E.

1998-01-01

Exposure of juvenile skeletal muscle to a weightless environment reduces growth and satellite cell mitotic activity. However, the effect of a weightless environment on the satellite cell population during muscle repair remains unknown. Muscle injury was induced in rat soleus muscles using the myotoxic snake venom, notexin. Rats were placed into hindlimb-suspended or weightbearing groups for 10 days following injury. Cellular proliferation during regeneration was evaluated using 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and image analysis. Hindlimb suspension reduced (P < 0.05) regenerated muscle mass, regenerated myofiber diameter, uninjured muscle mass, and uninjured myofiber diameter compared to weightbearing rats. Hindlimb suspension reduced (P < 0.05) BrdU labeling in uninjured soleus muscles compared to weight-bearing muscles. However, hindlimb suspension did not abolish muscle regeneration because myofibers formed in the injured soleus muscles of hindlimb-suspended rats, and BrdU labeling was equivalent (P > 0.10) on myofiber segments isolated from the soleus muscles of hindlimb-suspended and weightbearing rats following injury. Thus, hindlimb suspension (weightlessness) does not suppress satellite cell mitotic activity in regenerating muscles before myofiber formation, but reduces growth of the newly formed myofibers.

Macrophages are necessary for epimorphic regeneration in African spiny mice

PubMed Central

Simkin, Jennifer; Gawriluk, Thomas R; Gensel, John C; Seifert, Ashley W

2017-01-01

How the immune system affects tissue regeneration is not well understood. In this study, we used an emerging mammalian model of epimorphic regeneration, the African spiny mouse, to examine cell-based inflammation and tested the hypothesis that macrophages are necessary for regeneration. By directly comparing inflammatory cell activation in a 4 mm ear injury during regeneration (Acomys cahirinus) and scarring (Mus musculus), we found that both species exhibited an acute inflammatory response, with scarring characterized by stronger myeloperoxidase activity. In contrast, ROS production was stronger and more persistent during regeneration. By depleting macrophages during injury, we demonstrate a functional requirement for these cells to stimulate regeneration. Importantly, the spatial distribution of activated macrophage subtypes was unique during regeneration with pro-inflammatory macrophages failing to infiltrate the regeneration blastema. Together, our results demonstrate an essential role for inflammatory cells to regulate a regenerative response. DOI: http://dx.doi.org/10.7554/eLife.24623.001 PMID:28508748

Proresolving nanomedicines activate bone regeneration in periodontitis.

PubMed

Van Dyke, T E; Hasturk, H; Kantarci, A; Freire, M O; Nguyen, D; Dalli, J; Serhan, C N

2015-01-01

Therapies to reverse tissue damage from osteolytic inflammatory diseases are limited by the inability of current tissue-engineering procedures to restore lost hard and soft tissues. There is a critical need for new therapeutics in regeneration. In addition to scaffolds, cells, and soluble mediators necessary for tissue engineering, control of endogenous inflammation is an absolute requirement for success. Although significant progress has been made in understanding natural resolution of inflammation pathways to limit uncontrolled inflammation in disease, harnessing the biomimetic properties of proresolving lipid mediators has not been demonstrated. Here, we report the use of nano-proresolving medicines (NPRM) containing a novel lipoxin analog (benzo-lipoxin A4, bLXA4) to promote regeneration of hard and soft tissues irreversibly lost to periodontitis in the Hanford miniature pig. In this proof-of-principle experiment, NPRM-bLXA4 dramatically reduced inflammatory cell infiltrate into chronic periodontal disease sites treated surgically and dramatically increased new bone formation and regeneration of the periodontal organ. These findings indicate that NPRM-bLXA4 is a mimetic of endogenous resolving mechanisms with potent bioactions that offers a new therapeutic tissue-engineering approach for the treatment of chronic osteolytic inflammatory diseases. © International & American Associations for Dental Research 2014.

Efficient removal of antibiotics in a fluidized bed reactor by facile fabricated magnetic powdered activated carbon.

PubMed

Ma, Jianqing; Yang, Qunfeng; Xu, Dongmei; Zeng, Xiaomei; Wen, Yuezhong; Liu, Weiping

2017-02-01

Powdered activated carbons (PACs) with micrometer size are showing great potential for enabling and improving technologies in water treatment. The critical problem in achieving practical application of PAC involves simple, effective fabrication of magnetic PAC and the design of a feasible reactor that can remove pollutants and recover the adsorbent efficiently. Herein, we show that such materials can be fabricated by the combination of PAC and magnetic Fe 3 O 4 with chitosan-Fe hydrogel through a simple co-precipitation method. According to the characterization results, CS-Fe/Fe 3 O 4 /PAC with different micrometers in size exhibited excellent magnetic properties. The adsorption of tetracycline was fast and efficient, and 99.9% removal was achieved in 30 min. It also possesses good usability and stability to co-existing ions, organics, and different pH values due to its dispersive interaction nature. Finally, the prepared CS-Fe/Fe 3 O 4 /PAC also performed well in the fluidized bed reactor with electromagnetic separation function. It could be easily separated by applying a magnetic field and was effectively in situ regenerated, indicating a potential of practical application for the removal of pollutants from water.

HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver

PubMed Central

Sun, Yue; Chen, Yutian; Swendeman, Steven L.; Jung, Bongnam; Chavez, Deebly; Cao, Zhongwei; Christoffersen, Christina; Nielsen, Lars Bo; Schwab, Susan R.; Rafii, Shahin; Hla, Timothy

2016-01-01

Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) by its natural ligand bound to HDL (HDL-S1P) induces liver regeneration and curtails fibrosis. In mice lacking HDL-S1P, liver regeneration after partial hepatectomy was impeded and associated with aberrant vascular remodeling, thrombosis and peri-sinusoidal fibrosis. Notably, this “maladaptive repair” phenotype was recapitulated in mice that lack S1P1 in the endothelium. Reciprocally, enhanced plasma levels of HDL-S1P or administration of SEW2871, a pharmacological agonist specific for S1P1 enhanced regeneration of metabolically functional vasculature and alleviated fibrosis in mouse chronic injury and cholestasis models. This study shows that natural and pharmacological ligands modulate endothelial S1P1 to stimulate liver regeneration and inhibit fibrosis, suggesting that activation of this pathway may be a novel therapeutic strategy for liver fibrosis. PMID:28018969

Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo.

PubMed

Ward, Patricia J; Jones, Laura N; Mulligan, Amanda; Goolsby, William; Wilhelm, Jennifer C; English, Arthur W

2016-01-01

Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation) that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2), we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2) to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555) was greater in mice that received optical treatment. Thus, the acute (1 hour), one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-). We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons.

Reconstituted High-Density Lipoprotein Containing Human Growth Hormone-1 Shows Potent Tissue Regeneration Activity with Enhancement of Anti-Oxidant and Anti-Atherosclerotic Activities.

PubMed

Lee, Eun-Young; Kim, So-Hee; Cho, Kyung-Hyun

2015-06-01

Human growth hormone-1 (GH-1), somatotropin, is a peptide hormone that stimulates cell division in tissues such as bone and cartilage. To compare physiological activities in lipid-free and lipid-bound states, we expressed and incorporated GH-1 in reconstituted high-density lipoprotein (rHDL). GH-1 was expressed and purified using the pET30(a) vector and an Escherichia coli expression system. Purified GH-1 (at least 98% purity, 23 kD) was characterized and synthesized with apolipoproteinA-I (apoA-I), 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC), and cholesterol. Secondary structure analysis of GH-1 revealed 54% α-helical content in a lipid-free state and 65% α-helical content in a lipid-bound state along with blue-shifted tryptophan movement (around 2 nm). GH-1 caused less uptake of oxidized low-density lipoprotein (oxLDL) into macrophages and inhibited senescence of dermal cells in a dose-dependent manner. GH-1 in a lipid-bound state exerted stronger inhibitory activity than in a lipid-free state, indicating improved anti-atherosclerotic activity due to the lipid formulation. In a fin regeneration experiment using zebrafish (17 weeks old, n=9), GH-1 showed its highest regeneration speed without any side effects. GH-1-rHDL containing apoA-I showed 2.3-fold and 1.6-fold higher regeneration speeds than lipid-free GH-1 (in native state) and lipid-bound GH-1, respectively. Incorporation of GH-1 and apoA-I in HDL enhanced tissue regeneration activity of amputated tail fin, indicating a synergetic effect between GH-1 and apoA-I in a lipid-bound state.

Influence of magnetization on the applied magnetic field in various AMR regenerators

NASA Astrophysics Data System (ADS)

Mira, A.; de Larochelambert, T.; Espanet, C.; Giurgea, S.; Nika, P.; Bahl, C. R. H.; Bjørk, R.; Nielsen, K. K.

2017-10-01

The aim of this work is to assess the influence of a magnetic sample on the applied magnetic field inside the air gap of a magnetic circuit. Different magnetic sources including an electromagnet, a permanent magnet in a soft ferromagnetic toroidal yoke, as well as 2D and 3D Halbach cylinders are considered, using a numerical model. Gadolinium is chosen as magnetic material for the sample, due to its strong magnetocaloric properties and its wide use in magnetic refrigeration prototypes. We find that using uniform theoretical demagnetizing factors for cylinders or spheres results in a deviation of less than 2% in the calculation of internal magnetic fields at temperatures above the Curie point of gadolinium. Below the Curie point, a stronger magnetization of the cylinders and spheres leads to a larger deviation which can reach 8% when using uniform demagnetizing factors for internal magnetic field calculations.

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis.

PubMed

Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

2018-02-07

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20-40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

PubMed Central

Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

2018-01-01

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field. PMID:29414875

Feasibility analysis of reciprocating magnetic heat pumps

NASA Technical Reports Server (NTRS)

Larson, A. V.; Hartley, J. G.; Shelton, Sam V.; Smith, M. M.

1989-01-01

A reciprocating gadolinium core in a regeneration fluid column in the warm bore of a superconducting solenoidal magnet is considered for magnetic refrigeration in 3.517 MW (1000 ton) applications. A procedure is presented to minimize the amount of superconducting cable needed in the magnet design. Estimated system capital costs for an ideal magnetic refrigerator of this type become comparable to conventional chillers as the frequency of reciprocation approaches 10 Hertz. A 1-D finite difference analysis of a regenerator cycling at 0.027 Hertz is presented which exhibits some of the features seen in the experiments of G. V. Brown.

Review: Biological and Molecular Differences between Tail Regeneration and Limb Scarring in Lizard: An Inspiring Model Addressing Limb Regeneration in Amniotes.

PubMed

Alibardi, Lorenzo

2017-09-01

Tissue regeneration in lizards represents a unique model of regeneration and scarring in amniotes. The tail and limb contain putative stem cells but also dedifferentiating cells contribute to regeneration. Following tail amputation, inflammation is low and cell proliferation high, leading to regeneration while the intense inflammation in the limb leads to low proliferation and scarring. FGFs stimulate tail and limb regeneration and are present in the wound epidermis and blastema while they disappear in the limb wound epidermis 2-3 weeks postamputation in the scarring outgrowth. FGFs localize in the tail blastema and the apical epidermal peg (AEP), an epidermal microregion that allows tail growth but is absent in the limb. Inflammatory cells invade the limb blastema and wound epidermis, impeding the formation of an AEP. An embryonic program of growth is activated in the tail, dominated by Wnt-positive and -negative regulators of cell proliferation and noncoding RNAs, that represent the key regenerative genes. The balanced actions of these regulators likely impede the formation of a tumor in the tail tip. Genes for FACIT and fibrillar collagens, protease inhibitors, and embryonic keratins are upregulated in the regenerating tail blastema. A strong downregulation of genes for both B and T-lymphocyte activation suggests the regenerating tail blastema is a temporal immune-tolerated organ, whereas a scarring program is activated in the limb. Wnt inhibitors, pro-inflammatory genes, negative regulators of cell proliferation, downregulation of myogenic genes, proteases, and oxidases favoring scarring are upregulated. The evolution of an efficient immune system may be the main limiting barrier for organ regeneration in amniotes, and the poor regeneration of mammals and birds is associated with the efficiency of their mature immune system. This does not tolerate embryonic antigens formed in reprogrammed embryonic cells (as for neoplastic cells) that are consequently

Dynamics of Permanent-Magnet Biased Active Magnetic Bearings

NASA Technical Reports Server (NTRS)

Fukata, Satoru; Yutani, Kazuyuki

1996-01-01

Active magnetic radial bearings are constructed with a combination of permanent magnets to provide bias forces and electromagnets to generate control forces for the reduction of cost and the operating energy consumption. Ring-shaped permanent magnets with axial magnetization are attached to a shaft and share their magnet stators with the electromagnets. The magnet cores are made of solid iron for simplicity. A simplified magnetic circuit of the combined magnet system is analyzed with linear circuit theory by approximating the characteristics of permanent magnets with a linear relation. A linearized dynamical model of the control force is presented with the first-order approximation of the effects of eddy currents. Frequency responses of the rotor motion to disturbance inputs and the motion for impulsive forces are tested in the non-rotating state. The frequency responses are compared with numerical results. The decay of rotor speed due to magnetic braking is examined. The experimental results and the presented linearized model are similar to those of the all-electromagnetic design.

Magnetic refrigeration apparatus and method

DOEpatents

Barclay, J.A.; Overton, W.C. Jr.; Stewart, W.F.

The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

Magnetic refrigeration apparatus and method

DOEpatents

Barclay, John A.; Overton, Jr., William C.; Stewart, Walter F.

1984-01-01

The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

Permanent Magnet Synchronous Motor Driven by PWM Inverter with Voltage Booster with Regenerating Capability Augmented by Double-Layer Capacitor

NASA Astrophysics Data System (ADS)

Yamamoto, Kichiro; Shinohara, Katsuji; Furukawa, Shinya

An interior permanent magnet (IPM) motor drive system which has regenerating capability augmented by double-layer capacitors is proposed. The motor is driven by a PWM inverter with voltage booster. The voltage booster is used to control the dc link voltage in high speed region to improve the system efficiency. Furthermore, the double-layer capacitor as a storage element is combined with the PWM inverter with voltage booster to gain the efficiency for the regenerating operation. In this system, normally, the regenerative power does not return to a battery directly but is stored in the double-layer capacitors for the next motoring action to suppress the excessive regenerative current to battery, and the regenerative power returns to the battery when the regenerative energy is larger than a certain value. The charging current to the battery is controlled to a constant value to extend the life-time of the battery. The transient and steady state characteristics of the system for 1.5kW IPM motor are investigated by both simulation and experiment. Finally, the effectiveness of the system is demonstrated by the simulated and experimental results.

Resolving Heart Regeneration by Replacement Histone Profiling.

PubMed

Goldman, Joseph Aaron; Kuzu, Guray; Lee, Nutishia; Karasik, Jaclyn; Gemberling, Matthew; Foglia, Matthew J; Karra, Ravi; Dickson, Amy L; Sun, Fei; Tolstorukov, Michael Y; Poss, Kenneth D

2017-02-27

Chromatin regulation is a principal mechanism governing animal development, yet it is unclear to what extent structural changes in chromatin underlie tissue regeneration. Non-mammalian vertebrates such as zebrafish activate cardiomyocyte (CM) division after tissue damage to regenerate lost heart muscle. Here, we generated transgenic zebrafish expressing a biotinylatable H3.3 histone variant in CMs and derived cell-type-specific profiles of histone replacement. We identified an emerging program of putative enhancers that revise H3.3 occupancy during regeneration, overlaid upon a genome-wide reduction of H3.3 from promoters. In transgenic reporter lines, H3.3-enriched elements directed gene expression in subpopulations of CMs. Other elements increased H3.3 enrichment and displayed enhancer activity in settings of injury- and/or Neuregulin1-elicited CM proliferation. Dozens of consensus sequence motifs containing predicted transcription factor binding sites were enriched in genomic regions with regeneration-responsive H3.3 occupancy. Thus, cell-type-specific regulatory programs of tissue regeneration can be revealed by genome-wide H3.3 profiling. Copyright © 2017 Elsevier Inc. All rights reserved.

The Feasibility Study of Persulfate Oxidation to Regenerating of Spent Granular Activated Carbon

EPA Science Inventory

Chemical oxidation is a developing technology used to regenerate contaminant-spent GAC. Chemical regeneration of GAC represents a viable option to thermal regeneration methods that are energy intensive resulting in significant consumption of fossil fuels and production of greenho...

Active Regions' Magnetic Connection

NASA Image and Video Library

2017-05-22

Several bright bands of plasma connect from one active region to another, even though they are tens of thousands of miles away from each other (May 17-18, 2017). Active regions are, by their nature, strong magnetic areas with north and south poles. The plasma consists of charged particles that stream along the magnetic field lines between these two regions. These connecting lines are clearly visible in this wavelength of extreme ultraviolet light. Other loops and strands of bright plasma can be seen rising up and out of smaller active regions as well. The video covers about one day's worth of activity. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21638

Regenerable cobalt oxide loaded magnetosphere catalyst from fly ash for mercury removal in coal combustion flue gas.

PubMed

Yang, Jianping; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

2014-12-16

To remove Hg(0) in coal combustion flue gas and eliminate secondary mercury pollution of the spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst, with an optimal loading of 5.8% cobalt species, attained approximately 95% Hg(0) removal efficiency at 150 °C under simulated flue gas atmosphere. O2 could enhance the Hg(0) removal activity of magnetospheres catalyst via the Mars-Maessen mechanism. SO2 displayed an inhibitive effect on Hg(0) removal capacity. NO with lower concentration could promote the Hg(0) removal efficiency. However, when increasing the NO concentration to 300 ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm of HCl, greater than 95.5% Hg(0) removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented a seriously inhibitive effect on Hg(0) removal efficiency. Repeated oxidation-regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400 °C for 2 h.

Atf3 mutant mice show reduced axon regeneration and impaired regeneration-associated gene induction after peripheral nerve injury

PubMed Central

Gey, Manuel; Wanner, Renate; Schilling, Corinna; Pedro, Maria T.; Sinske, Daniela

2016-01-01

Axon injury in the peripheral nervous system (PNS) induces a regeneration-associated gene (RAG) response. Atf3 (activating transcription factor 3) is such a RAG and ATF3's transcriptional activity might induce ‘effector’ RAGs (e.g. small proline rich protein 1a (Sprr1a), Galanin (Gal), growth-associated protein 43 (Gap43)) facilitating peripheral axon regeneration. We provide a first analysis of Atf3 mouse mutants in peripheral nerve regeneration. In Atf3 mutant mice, facial nerve regeneration and neurite outgrowth of adult ATF3-deficient primary dorsal root ganglia neurons was decreased. Using genome-wide transcriptomics, we identified a neuropeptide-encoding RAG cluster (vasoactive intestinal peptide (Vip), Ngf, Grp, Gal, Pacap) regulated by ATF3. Exogenous administration of neuropeptides enhanced neurite growth of Atf3 mutant mice suggesting that these molecules might be effector RAGs of ATF3's pro-regenerative function. In addition to the induction of growth-promoting molecules, we present data that ATF3 suppresses growth-inhibiting molecules such as chemokine (C-C motif) ligand 2. In summary, we show a pro-regenerative ATF3 function during PNS nerve regeneration involving transcriptional activation of a neuropeptide-encoding RAG cluster. ATF3 is a general injury-inducible factor, therefore ATF3-mediated mechanisms identified herein might apply to other cell and injury types. PMID:27581653

In-situ regeneration of activated carbon with electric potential swing desorption (EPSD) for the H2S removal from biogas.

PubMed

Farooq, M; Almustapha, M N; Imran, M; Saeed, M A; Andresen, John M

2018-02-01

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 H 2 S. Breakthrough times, adsorption desorption volume, capacities, effect of regeneration and desorption kinetics were investigated. The analysis showed that desorption of H 2 S 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. Copyright © 2017 Elsevier Ltd. All rights reserved.

mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

PubMed

Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

2015-02-01

Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

cAMP-responsive Element-binding Protein (CREB) and cAMP Co-regulate Activator Protein 1 (AP1)-dependent Regeneration-associated Gene Expression and Neurite Growth*

PubMed Central

Ma, Thong C.; Barco, Angel; Ratan, Rajiv R.; Willis, Dianna E.

2014-01-01

To regenerate damaged axons, neurons must express a cassette of regeneration-associated genes (RAGs) that increases intrinsic growth capacity and confers resistance to extrinsic inhibitory cues. Here we show that dibutyrl-cAMP or forskolin combined with constitutive-active CREB are superior to either agent alone in driving neurite growth on permissive and inhibitory substrates. Of the RAGs examined, only arginase 1 (Arg1) expression correlated with the increased neurite growth induced by the cAMP/CREB combination, both of which were AP1-dependent. This suggests that cAMP-induced AP1 activity is necessary and interacts with CREB to drive expression of RAGs relevant for regeneration and demonstrates that combining a small molecule (cAMP) with an activated transcription factor (CREB) stimulates the gene expression necessary to enhance axonal regeneration. PMID:25296755

Active Tensor Magnetic Gradiometer System

DTIC Science & Technology

2007-11-01

Modify Forward Computer Models .............................................................................................2 Modify TMGS Simulator...active magnetic gradient measurement system are based upon the existing tensor magnetic gradiometer system ( TMGS ) developed under project MM-1328...Magnetic Gradiometer System ( TMGS ) for UXO Detection, Imaging, and Discrimination.” The TMGS developed under MM-1328 was successfully tested at the

Vertebrate-like regeneration in the invertebrate chordate amphioxus

PubMed Central

Somorjai, Ildikó M. L.; Garcia-Fernàndez, Jordi; Escrivà, Hector

2012-01-01

An important question in biology is why some animals are able to regenerate, whereas others are not. The basal chordate amphioxus is uniquely positioned to address the evolution of regeneration. We report here the high regeneration potential of the European amphioxus Branchiostoma lanceolatum. Adults regenerate both anterior and posterior structures, including neural tube, notochord, fin, and muscle. Development of a classifier based on tail regeneration profiles predicts the assignment of young and old adults to their own class with >94% accuracy. The process involves loss of differentiated characteristics, formation of an msx-expressing blastema, and neurogenesis. Moreover, regeneration is linked to the activation of satellite-like Pax3/7 progenitor cells, the extent of which declines with size and age. Our results provide a framework for understanding the evolution and diversity of regeneration mechanisms in vertebrates. PMID:22203957

Activation of germline-specific genes is required for limb regeneration in the Mexican axolotl

PubMed Central

Zhu, Wei; Pao, Gerald M; Satoh, Akira; Cummings, Gillian; Monaghan, James R; Harkins, Timothy T; Bryant, Susan V; Voss, S Randal; Gardiner, David M; Hunter, Tony

2013-01-01

The capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. Emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration – wound healing, cellular dedifferentiation and blastemal formation – will reveal therapeutic approaches for tissue regeneration in humans. Here we describe a unique transcriptional fingerprint of regenerating limb tissue in the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells to a germline-like state. Two genes that are required for self-renewal of germ cells in mice and flies, Piwi-like 1 (PL1) and Piwi-like 2 (PL2), are expressed in limb blastemal cells, the basal layer keratinocytes and the thickened apical epithelial cap in the wound epidermis in the regenerating limb. Depletion of PL1 and PL2 by morpholino oligonucleotides decreased cell proliferation and increased cell death in the blastema leading to a significant retardation of regeneration. Examination of key molecules that are known to be required for limb development or regeneration further revealed that FGF8 is transcriptionally downregulated in the presence of the morpholino oligos, indicating PL1 and PL2 might participate in FGF signaling during limb regeneration. Given the requirement for FGF signaling in limb development and regeneration, the results suggest that PL1 and PL2 function to establish a unique germline-like state that is associated with successful regeneration. PMID:22841627

A numerical analysis of a magnetocaloric refrigerator with a 16-layer regenerator.

PubMed

Zhang, Mingkan; Abdelaziz, Omar; Momen, Ayyoub M; Abu-Heiba, Ahmad

2017-10-25

A numerical analysis was conducted to study a room temperature magnetocaloric refrigerator with a 16-layer parallel plates active magnetic regenerator (AMR). Sixteen layers of LaFeMnSiH having different Curie temperatures were employed as magnetocaloric material (MCM) in the regenerator. Measured properties data was used. A transient one dimensional (1D) model was employed, in which a unique numerical method was developed to significantly accelerate the simulation speed of the multi-layer AMR system. As a result, the computation speed of a multi-layer AMR case was very close to the single-layer configuration. The performance of the 16-layer AMR system in different frequencies and utilizations has been investigated using this model. To optimize the layer length distribution of the 16-layer MCMs in the regenerator, a set of 137 simulations with different MCM distributions based on the Design of Experiments (DoE) method was conducted and the results were analyzed. The results show that the 16-layer AMR system can operate up to 84% of Carnot cycle COP at a temperature span of 41 K, which cannot be obtained using an AMR with fewer layers. The DoE results indicate that for a 16-layer AMR system, the uniform distribution is very close to the optimized design.

Extraocular muscle regeneration in zebrafish requires late signals from Insulin-like growth factors.

PubMed

Saera-Vila, Alfonso; Louie, Ke'ale W; Sha, Cuilee; Kelly, Ryan M; Kish, Phillip E; Kahana, Alon

2018-01-01

Insulin-like growth factors (Igfs) are key regulators of key biological processes such as embryonic development, growth, and tissue repair and regeneration. The role of Igf in myogenesis is well documented and, in zebrafish, promotes fin and heart regeneration. However, the mechanism of action of Igf in muscle repair and regeneration is not well understood. Using adult zebrafish extraocular muscle (EOM) regeneration as an experimental model, we show that Igf1 receptor blockage using either chemical inhibitors (BMS754807 and NVP-AEW541) or translation-blocking morpholino oligonucleotides (MOs) reduced EOM regeneration. Zebrafish EOMs regeneration depends on myocyte dedifferentiation, which is driven by early epigenetic reprogramming and requires autophagy activation and cell cycle reentry. Inhibition of Igf signaling had no effect on either autophagy activation or cell proliferation, indicating that Igf signaling was not involved in the early reprogramming steps of regeneration. Instead, blocking Igf signaling produced hypercellularity of regenerating EOMs and diminished myosin expression, resulting in lack of mature differentiated muscle fibers even many days after injury, indicating that Igf was involved in late re-differentiation steps. Although it is considered the main mediator of myogenic Igf actions, Akt activation decreased in regenerating EOMs, suggesting that alternative signaling pathways mediate Igf activity in muscle regeneration. In conclusion, Igf signaling is critical for re-differentiation of reprogrammed myoblasts during late steps of zebrafish EOM regeneration, suggesting a regulatory mechanism for determining regenerated muscle size and timing of differentiation, and a potential target for regenerative therapy.

p53 on the crossroad between regeneration and cancer.

PubMed

Charni, Meital; Aloni-Grinstein, Ronit; Molchadsky, Alina; Rotter, Varda

2017-01-01

Regeneration and tumorigenesis share common molecular pathways, nevertheless the outcome of regeneration is life, whereas tumorigenesis leads to death. Although the process of regeneration is strictly controlled, malignant transformation is unrestrained. In this review, we discuss the involvement of TP53, the major tumor-suppressor gene, in the regeneration process. We point to the role of p53 as coordinator assuring that regeneration will not shift to carcinogenesis. The fluctuation in p53 activity during the regeneration process permits a tight control. On one hand, its inhibition at the initial stages allows massive proliferation, on the other its induction at advanced steps of regeneration is essential for preservation of robustness and fidelity of the regeneration process. A better understanding of the role of p53 in regulation of regeneration may open new opportunities for implementation of TP53-based therapies, currently available for cancer patients, in regenerative medicine.

Vitamin C treatment promotes mesenchymal stem cell sheet formation and tissue regeneration by elevating telomerase activity.

PubMed

Wei, Fulan; Qu, Cunye; Song, Tieli; Ding, Gang; Fan, Zhipeng; Liu, Dayong; Liu, Yi; Zhang, Chunmei; Shi, Songtao; Wang, Songlin

2012-09-01

Cell sheet engineering has been developed as an alternative approach to improve mesenchymal stem cell-mediated tissue regeneration. In this study, we found that vitamin C (Vc) was capable of inducing telomerase activity in periodontal ligament stem cells (PDLSCs), leading to the up-regulated expression of extracellular matrix type I collagen, fibronectin, and integrin β1, stem cell markers Oct4, Sox2, and Nanog as well as osteogenic markers RUNX2, ALP, OCN. Under Vc treatment, PDLSCs can form cell sheet structures because of increased cell matrix production. Interestingly, PDLSC sheets demonstrated a significant improvement in tissue regeneration compared with untreated control dissociated PDLSCs and offered an effective treatment for periodontal defects in a swine model. In addition, bone marrow mesenchymal stem cell sheets and umbilical cord mesenchymal stem cell sheets were also well constructed using this method. The development of Vc-mediated mesenchymal stem cell sheets may provide an easy and practical approach for cell-based tissue regeneration. Copyright © 2011 Wiley Periodicals, Inc.

Epoxyeicosanoids promote organ and tissue regeneration.

PubMed

Panigrahy, Dipak; Kalish, Brian T; Huang, Sui; Bielenberg, Diane R; Le, Hau D; Yang, Jun; Edin, Matthew L; Lee, Craig R; Benny, Ofra; Mudge, Dayna K; Butterfield, Catherine E; Mammoto, Akiko; Mammoto, Tadanori; Inceoglu, Bora; Jenkins, Roger L; Simpson, Mary A; Akino, Tomoshige; Lih, Fred B; Tomer, Kenneth B; Ingber, Donald E; Hammock, Bruce D; Falck, John R; Manthati, Vijaya L; Kaipainen, Arja; D'Amore, Patricia A; Puder, Mark; Zeldin, Darryl C; Kieran, Mark W

2013-08-13

Epoxyeicosatrienoic acids (EETs), lipid mediators produced by cytochrome P450 epoxygenases, regulate inflammation, angiogenesis, and vascular tone. Despite pleiotropic effects on cells, the role of these epoxyeicosanoids in normal organ and tissue regeneration remains unknown. EETs are produced predominantly in the endothelium. Normal organ and tissue regeneration require an active paracrine role of the microvascular endothelium, which in turn depends on angiogenic growth factors. Thus, we hypothesize that endothelial cells stimulate organ and tissue regeneration via production of bioactive EETs. To determine whether endothelial-derived EETs affect physiologic tissue growth in vivo, we used genetic and pharmacological tools to manipulate endogenous EET levels. We show that endothelial-derived EETs play a critical role in accelerating tissue growth in vivo, including liver regeneration, kidney compensatory growth, lung compensatory growth, wound healing, corneal neovascularization, and retinal vascularization. Administration of synthetic EETs recapitulated these results, whereas lowering EET levels, either genetically or pharmacologically, delayed tissue regeneration, demonstrating that pharmacological modulation of EETs can affect normal organ and tissue growth. We also show that soluble epoxide hydrolase inhibitors, which elevate endogenous EET levels, promote liver and lung regeneration. Thus, our observations indicate a central role for EETs in organ and tissue regeneration and their contribution to tissue homeostasis.

FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC

EPA Science Inventory

Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was chemically regenerated utilizing the Fenton mechanism. Two successive GAC regeneration cycles were performed involving iterative adsorption and oxidation processes: MTBE was adsorbed to the GAC, oxidized, r...

Delta-configurations - Flare activity and magnetic-field structure

NASA Technical Reports Server (NTRS)

Patty, S. R.; Hagyard, M. J.

1986-01-01

Complex sunspots in four active regions of April and May 1980, all exhibiting regions of magnetic classification delta, were studied using data from the NASA Marshall Space Flight Center vector magnetograph. The vector magnetic field structure in the vicinity of each delta was determined, and the location of the deltas in each active region was correlated with the locations and types of flare activity for the regions. Two types of delta-configuration were found to exist, active and inactive, as defined by the relationships between magnetic field structure and activity. The active delta exhibited high flare activity, strong horizontal gradients of the longitudinal (line-of-sight) magnetic field component, a strong transverse (perpendicular to line-of-sight) component, and a highly nonpotential orientation of the photospheric magnetic field, all indications of a highly sheared magnetic field. The inactive delta, on the other hand, exhibited little or no flare production, weaker horizontal gradients of the longitudinal component, weaker transverse components, and a nearly potential, nonsheared orientation of the magnetic field. It is concluded that the presence of such sheared fields is the primary signature by which the active delta may be distinguished, and that it is this shear which produces the flare activity of the active delta.

The Magnetic Free Energy in Active Regions

NASA Technical Reports Server (NTRS)

Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

2001-01-01

The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

Combined chemical and structural signals of biomaterials synergistically activate cell-cell communications for improving tissue regeneration.

PubMed

Xu, Yachen; Peng, Jinliang; Dong, Xin; Xu, Yuhong; Li, Haiyan; Chang, Jiang

2017-06-01

Biomaterials are only used as carriers of cells in the conventional tissue engineering. Considering the multi-cell environment and active cell-biomaterial interactions in tissue regeneration process, in this study, structural signals of aligned electrospun nanofibers and chemical signals of bioglass (BG) ionic products in cell culture medium are simultaneously applied to activate fibroblast-endothelial co-cultured cells in order to obtain an improved skin tissue engineering construct. Results demonstrate that the combined biomaterial signals synergistically activate fibroblast-endothelial co-culture skin tissue engineering constructs through promotion of paracrine effects and stimulation of gap junctional communication between cells, which results in enhanced vascularization and extracellular matrix protein synthesis in the constructs. Structural signals of aligned electrospun nanofibers play an important role in stimulating both of paracrine and gap junctional communication while chemical signals of BG ionic products mainly enhance paracrine effects. In vivo experiments reveal that the activated skin tissue engineering constructs significantly enhance wound healing as compared to control. This study indicates the advantages of synergistic effects between different bioactive signals of biomaterials can be taken to activate communication between different types of cells for obtaining tissue engineering constructs with improved functions. Tissue engineering can regenerate or replace tissue or organs through combining cells, biomaterials and growth factors. Normally, for repairing a specific tissue, only one type of cells, one kind of biomaterials, and specific growth factors are used to support cell growth. In this study, we proposed a novel tissue engineering approach by simply using co-cultured cells and combined biomaterial signals. Using a skin tissue engineering model, we successfully proved that the combined biomaterial signals such as surface nanostructures

Granular activated carbon adsorption and microwave regeneration for the treatment of 2,4,5-trichlorobiphenyl in simulated soil-washing solution.

PubMed

Liu, Xitao; Yu, Gang; Han, Wenya

2007-08-25

The treatment of 2,4,5-trichlorobiphenyl (PCB29) in simulated soil-washing solution by granular activated carbon (GAC) adsorption and microwave (MW) regeneration was investigated in this study. The PCB29 adsorption process was carried out in a continuous flow adsorption column. After adsorption, the PCB29-loaded GAC was dried at 103 degrees C, and regenerated in a quartz reactor by 2450MHz MW irradiation at 700W for 5min. The efficacy of this procedure was analyzed by determining the rates and amounts of PCB29 adsorbed in successive adsorption/MW regeneration cycles. Effects of the regeneration on the textural properties and the PCB29 adsorption capacity of GAC were examined. It was found that after several adsorption/MW regeneration cycles, the adsorption rate of GAC increased, whereas, the adsorption capacity decreased, which could be explained according to the change of textural properties. Most of the PCB29 adsorbed on GAC was degraded within 3min under MW irradiation, and the analysis of degradation products by GC-MS demonstrated that PCB29 experienced dechlorination during this treatment.

Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

PubMed

Lee, Sang Goo; Huang, Mingqian; Obholzer, Nikolaus D; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A; Megason, Sean G; Li, Huawei; Chen, Zheng-Yi

2016-01-01

Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration

PubMed Central

Obholzer, Nikolaus D.; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A.; Megason, Sean G.; Li, Huawei; Chen, Zheng-Yi

2016-01-01

Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration. PMID:27351484

Inflammation and immunity in organ regeneration.

PubMed

Mescher, Anthony L; Neff, Anton W; King, Michael W

2017-01-01

The ability of vertebrates to regenerate amputated appendages is increasingly well-understood at the cellular level. Cells mediating an innate immune response and inflammation in the injured tissues are a prominent feature of the limb prior to formation of a regeneration blastema, with macrophage activity necessary for blastema growth and successful development of the new limb. Studies involving either anti-inflammatory or pro-inflammatory agents suggest that the local inflammation produced by injury and its timely resolution are both important for regeneration, with blastema patterning inhibited in the presence of unresolved inflammation. Various experiments with Xenopus larvae at stages where regenerative competence is declining show improved digit formation after treatment with certain immunosuppressive, anti-inflammatory, or antioxidant agents. Similar work with the larval Xenopus tail has implicated adaptive immunity with regenerative competence and suggests a requirement for regulatory T cells in regeneration, which also occurs in many systems of tissue regeneration. Recent analyses of the human nail organ indicate a capacity for local immune tolerance, suggesting roles for adaptive immunity in the capacity for mammalian appendage regeneration. New information and better understanding regarding the neuroendocrine-immune axis in the response to stressors, including amputation, suggest additional approaches useful for investigating effects of the immune system during repair and regeneration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical activity and the rejuvenation of Connswater (PARC study): protocol for a natural experiment investigating the impact of urban regeneration on public health

PubMed Central

2013-01-01

Background There is a dearth of evidence regarding the impact of urban regeneration projects on public health, particularly the nature and degree to which urban regeneration impacts upon health-related behaviour change. Natural experiment methodology enables comprehensive large-scale evaluations of such interventions. The Connswater Community Greenway in Belfast is a major urban regeneration project involving the development of a 9 km linear park, including the provision of new cycle paths and walkways. In addition to the environmental improvements, this complex intervention involves a number of programmes to promote physical activity in the regenerated area. The project affords a unique opportunity to investigate the public health impact of urban regeneration. Methods/Design The evaluation framework was informed by the socio-ecological model and guided by the RE-AIM Framework. Key components include: (1) a quasi-experimental before-and-after survey of the Greenway population (repeated cross-sectional design), in tandem with data from a parallel Northern Ireland-wide survey for comparison; (2) an assessment of changes in the local built environment and of walkability using geographic information systems; (3) semi-structured interviews with a purposive sample of survey respondents, and a range of community stakeholders, before and after the regeneration project; and (4) a cost-effectiveness analysis. The primary outcome is change in proportion of individuals identified as being regularly physically active, according to the current UK recommendations. The RE-AIM Framework will be used to make an overall assessment of the impact of the Greenway on the physical activity behaviour of local residents. Discussion The Connswater Community Greenway provides a significant opportunity to achieve long-term, population level behaviour change. We argue that urban regeneration may be conceptualised meaningfully as a complex intervention comprising multiple components with the

Physical activity and the rejuvenation of Connswater (PARC study): protocol for a natural experiment investigating the impact of urban regeneration on public health.

PubMed

Tully, Mark A; Hunter, Ruth F; McAneney, Helen; Cupples, Margaret E; Donnelly, Michael; Ellis, Geraint; Hutchinson, George; Prior, Lindsay; Stevenson, Michael; Kee, Frank

2013-08-23

There is a dearth of evidence regarding the impact of urban regeneration projects on public health, particularly the nature and degree to which urban regeneration impacts upon health-related behaviour change. Natural experiment methodology enables comprehensive large-scale evaluations of such interventions. The Connswater Community Greenway in Belfast is a major urban regeneration project involving the development of a 9 km linear park, including the provision of new cycle paths and walkways. In addition to the environmental improvements, this complex intervention involves a number of programmes to promote physical activity in the regenerated area. The project affords a unique opportunity to investigate the public health impact of urban regeneration. The evaluation framework was informed by the socio-ecological model and guided by the RE-AIM Framework. Key components include: (1) a quasi-experimental before-and-after survey of the Greenway population (repeated cross-sectional design), in tandem with data from a parallel Northern Ireland-wide survey for comparison; (2) an assessment of changes in the local built environment and of walkability using geographic information systems; (3) semi-structured interviews with a purposive sample of survey respondents, and a range of community stakeholders, before and after the regeneration project; and (4) a cost-effectiveness analysis. The primary outcome is change in proportion of individuals identified as being regularly physically active, according to the current UK recommendations. The RE-AIM Framework will be used to make an overall assessment of the impact of the Greenway on the physical activity behaviour of local residents. The Connswater Community Greenway provides a significant opportunity to achieve long-term, population level behaviour change. We argue that urban regeneration may be conceptualised meaningfully as a complex intervention comprising multiple components with the potential, individually and

Combining Constitutively Active Rheb Expression and Chondroitinase Promotes Functional Axonal Regeneration after Cervical Spinal Cord Injury.

PubMed

Wu, Di; Klaw, Michelle C; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E; Côté, Marie-Pascale; Tom, Veronica J

2017-12-06

After spinal cord injury (SCI), severed axons in the adult mammalian CNS are unable to mount a robust regenerative response. In addition, the glial scar at the lesion site further restricts the regenerative potential of axons. We hypothesized that a combinatorial approach coincidentally targeting these obstacles would promote axonal regeneration. We combined (1) transplantation of a growth-permissive peripheral nerve graft (PNG) into an incomplete, cervical lesion cavity; (2) transduction of neurons rostral to the SCI site to express constitutively active Rheb (caRheb; a Ras homolog enriched in brain), a GTPase that directly activates the growth-promoting pathway mammalian target of rapamycin (mTOR) via AAV-caRheb injection; and (3) digestion of growth-inhibitory chondroitin sulfate proteoglycans within the glial scar at the distal PNG interface using the bacterial enzyme chondroitinase ABC (ChABC). We found that expressing caRheb in neurons post-SCI results in modestly yet significantly more axons regenerating across a ChABC-treated distal graft interface into caudal spinal cord than either treatment alone. Excitingly, we found that caRheb+ChABC treatment significantly potentiates the formation of synapses in the host spinal cord and improves the animals' ability to use the affected forelimb. Thus, this combination strategy enhances functional axonal regeneration following a cervical SCI. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Resveratrol Promotes Nerve Regeneration via Activation of p300 Acetyltransferase-Mediated VEGF Signaling in a Rat Model of Sciatic Nerve Crush Injury.

PubMed

Ding, Zhuofeng; Cao, Jiawei; Shen, Yu; Zou, Yu; Yang, Xin; Zhou, Wen; Guo, Qulian; Huang, Changsheng

2018-01-01

Peripheral nerve injuries are generally associated with incomplete restoration of motor function. The slow rate of nerve regeneration after injury may account for this. Although many benefits of resveratrol have been shown in the nervous system, it is not clear whether resveratrol could promote fast nerve regeneration and motor repair after peripheral nerve injury. This study showed that the motor deficits caused by sciatic nerve crush injury were alleviated by daily systematic resveratrol treatment within 10 days. Resveratrol increased the number of axons in the distal part of the injured nerve, indicating enhanced nerve regeneration. In the affected ventral spinal cord, resveratrol enhanced the expression of several vascular endothelial growth factor family proteins (VEGFs) and increased the phosphorylation of p300 through Akt signaling, indicating activation of p300 acetyltransferase. Inactivation of p300 acetyltransferase reversed the resveratrol-induced expression of VEGFs and motor repair in rats that had undergone sciatic nerve crush injury. The above results indicated that daily systematic resveratrol treatment promoted nerve regeneration and led to rapid motor repair. Resveratrol activated p300 acetyltransferase-mediated VEGF signaling in the affected ventral spinal cord, which may have thus contributed to the acceleration of nerve regeneration and motor repair.

Metal sulfide initiators for metal oxide sorbent regeneration

DOEpatents

Turk, Brian S.; Gupta, Raghubir P.

2001-01-01

A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing gas. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream.

Metal sulfide initiators for metal oxide sorbent regeneration

DOEpatents

Turk, Brian S.; Gupta, Raghubir P.

1999-01-01

A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream.

Metal sulfide initiators for metal oxide sorbent regeneration

DOEpatents

Turk, B.S.; Gupta, R.P.

1999-06-22

A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing gas. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream. 1 fig.

Insulin/IGF1 Signaling Inhibits Age-Dependent Axon Regeneration

PubMed Central

Byrne, Alexandra B.; Walradt, Trent; Gardner, Kathryn E.; Hubbert, Austin; Reinke, Valerie; Hammarlund, Marc

2014-01-01

Summary The ability of injured axons to regenerate declines with age yet the mechanisms that regulate axon regeneration in response to age are not known. Here we show that axon regeneration in aging C. elegans motor neurons is inhibited by the conserved insulin/IGF1 receptor DAF-2. DAF-2’s function in regeneration is mediated by intrinsic neuronal activity of the forkhead transcription factor DAF-16/FOXO. DAF-16 regulates regeneration independently of lifespan, indicating that neuronal aging is an intrinsic, neuron specific, and genetically regulated process. In addition, we found that daf-18/PTEN inhibits regeneration independently of age and FOXO signaling, via the TOR pathway. Finally, DLK-1, a conserved regulator of regeneration, is downregulated by insulin/IGF1 signaling, bound by DAF-16 in neurons, and is required for both DAF-16- and DAF-18-mediated regeneration. Together, our data establish that insulin signaling specifically inhibits regeneration in aging adult neurons, and that this mechanism is independent of PTEN and TOR. PMID:24440228

Tissue absence initiates regeneration through follistatin-mediated inhibition of activin signaling.

PubMed

Gaviño, Michael A; Wenemoser, Danielle; Wang, Irving E; Reddien, Peter W

2013-09-10

Regeneration is widespread, but mechanisms that activate regeneration remain mysterious. Planarians are capable of whole-body regeneration and mount distinct molecular responses to wounds that result in tissue absence and those that do not. A major question is how these distinct responses are activated. We describe a follistatin homolog (Smed-follistatin) required for planarian regeneration. Smed-follistatin inhibition blocks responses to tissue absence but does not prevent normal tissue turnover. Two activin homologs (Smed-activin-1 and Smed-activin-2) are required for the Smed-follistatin phenotype. Finally, Smed-follistatin is wound-induced and expressed at higher levels following injuries that cause tissue absence. These data suggest that Smed-follistatin inhibits Smed-Activin proteins to trigger regeneration specifically following injuries involving tissue absence and identify a mechanism critical for regeneration initiation, a process important across the animal kingdom. DOI:http://dx.doi.org/10.7554/eLife.00247.001.

A numerical analysis of a magnetocaloric refrigerator with a 16-layer regenerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Mingkan; Abdelaziz, Omar; Momen, Ayyoub Mehdizadeh

A numerical analysis was conducted to study a room temperature magnetocaloric refrigerator with a 16-layer parallel plates active magnetic regenerator (AMR). Sixteen layers of LaFeMnSiH having different Curie temperatures were employed as magnetocaloric material (MCM) in the regenerator. Measured properties data was used. A transient one dimensional (1D) model was employed, in which a unique numerical method was developed to significantly accelerate the simulation speed of the multi-layer AMR system. As a result, the computation speed of a multi-layer AMR case was very close to the single-layer configuration. The performance of the 16-layer AMR system in different frequencies and utilizationsmore » has been investigated using this model. To optimize the layer length distribution of the 16-layer MCMs in the regenerator, a set of 137 simulations with different MCM distributions based on the Design of Experiments (DoE) method was conducted and the results were analyzed. The results show that the 16-layer AMR system can operate up to 84% of Carnot cycle COP at a temperature span of 41 K, which cannot be obtained using an AMR with fewer layers. Here, the DoE results indicate that for a 16-layer AMR system, the uniform distribution is very close to the optimized design.« less

A numerical analysis of a magnetocaloric refrigerator with a 16-layer regenerator

DOE PAGES

Zhang, Mingkan; Abdelaziz, Omar; Momen, Ayyoub Mehdizadeh; ...

2017-10-25

A numerical analysis was conducted to study a room temperature magnetocaloric refrigerator with a 16-layer parallel plates active magnetic regenerator (AMR). Sixteen layers of LaFeMnSiH having different Curie temperatures were employed as magnetocaloric material (MCM) in the regenerator. Measured properties data was used. A transient one dimensional (1D) model was employed, in which a unique numerical method was developed to significantly accelerate the simulation speed of the multi-layer AMR system. As a result, the computation speed of a multi-layer AMR case was very close to the single-layer configuration. The performance of the 16-layer AMR system in different frequencies and utilizationsmore » has been investigated using this model. To optimize the layer length distribution of the 16-layer MCMs in the regenerator, a set of 137 simulations with different MCM distributions based on the Design of Experiments (DoE) method was conducted and the results were analyzed. The results show that the 16-layer AMR system can operate up to 84% of Carnot cycle COP at a temperature span of 41 K, which cannot be obtained using an AMR with fewer layers. Here, the DoE results indicate that for a 16-layer AMR system, the uniform distribution is very close to the optimized design.« less

Modulation of liver regeneration via myeloid PTEN deficiency

PubMed Central

Ma, Wen-Tao; Jia, Yan-Jie; Liu, Qing-Zhi; Yang, Yan-Qing; Yang, Jing-Bo; Zhao, Zhi-Bin; Yang, Zhen-Ye; Shi, Qing-Hua; Ma, Hong-Di; Gershwin, M Eric; Lian, Zhe-Xiong

2017-01-01

Molecular mechanisms that modulate liver regeneration are of critical importance for a number of hepatic disorders. Kupffer cells and natural killer (NK) cells are two cell subsets indispensable for liver regeneration. We have focused on these two populations and, in particular, the interplay between them. Importantly, we demonstrate that deletion of the myeloid phosphatase and tensin homolog on chromosome 10 (PTEN) leading to an M2-like polarization of Kupffer cells, which results in decreased activation of NK cells. In addition, PTEN-deficient Kupffer cells secrete additional factors that facilitate the proliferation of hepatocytes. In conclusion, PTEN is critical for inhibiting M2-like polarization of Kupffer cells after partial hepatectomy, resulting in NK cell activation and thus the inhibition of liver regeneration. Furthermore, PTEN reduces growth factor secretion by Kupffer cells. Our results suggest that targeting PTEN on Kupffer cells may be useful in altering liver regeneration in patients undergoing liver resection. PMID:28542148

Dynamics of a magnetic active Brownian particle under a uniform magnetic field.

PubMed

Vidal-Urquiza, Glenn C; Córdova-Figueroa, Ubaldo M

2017-11-01

The dynamics of a magnetic active Brownian particle undergoing three-dimensional Brownian motion, both translation and rotation, under the influence of a uniform magnetic field is investigated. The particle self-propels at a constant speed along its magnetic dipole moment, which reorients due to the interplay between Brownian and magnetic torques, quantified by the Langevin parameter α. In this work, the time-dependent active diffusivity and the crossover time (τ^{cross})-from ballistic to diffusive regimes-are calculated through the time-dependent correlation function of the fluctuations of the propulsion direction. The results reveal that, for any value of α, the particle undergoes a directional (or ballistic) propulsive motion at very short times (t≪τ^{cross}). In this regime, the correlation function decreases linearly with time, and the active diffusivity increases with it. It the opposite time limit (t≫τ^{cross}), the particle moves in a purely diffusive regime with a correlation function that decays asymptotically to zero and an active diffusivity that reaches a constant value equal to the long-time active diffusivity of the particle. As expected in the absence of a magnetic field (α=0), the crossover time is equal to the characteristic time scale for rotational diffusion, τ_{rot}. In the presence of a magnetic field (α>0), the correlation function, the active diffusivity, and the crossover time decrease with increasing α. The magnetic field regulates the regimes of propulsion of the particle. Here, the field reduces the period of time at which the active particle undergoes a directional motion. Consequently, the active particle rapidly reaches a diffusive regime at τ^{cross}≪τ_{rot}. In the limit of weak fields (α≪1), the crossover time decreases quadratically with α, while in the limit of strong fields (α≫1) it decays asymptotically as α^{-1}. The results are in excellent agreement with those obtained by Brownian dynamics

Dynamics of a magnetic active Brownian particle under a uniform magnetic field

NASA Astrophysics Data System (ADS)

Vidal-Urquiza, Glenn C.; Córdova-Figueroa, Ubaldo M.

2017-11-01

The dynamics of a magnetic active Brownian particle undergoing three-dimensional Brownian motion, both translation and rotation, under the influence of a uniform magnetic field is investigated. The particle self-propels at a constant speed along its magnetic dipole moment, which reorients due to the interplay between Brownian and magnetic torques, quantified by the Langevin parameter α . In this work, the time-dependent active diffusivity and the crossover time (τcross)—from ballistic to diffusive regimes—are calculated through the time-dependent correlation function of the fluctuations of the propulsion direction. The results reveal that, for any value of α , the particle undergoes a directional (or ballistic) propulsive motion at very short times (t ≪τcross ). In this regime, the correlation function decreases linearly with time, and the active diffusivity increases with it. It the opposite time limit (t ≫τcross ), the particle moves in a purely diffusive regime with a correlation function that decays asymptotically to zero and an active diffusivity that reaches a constant value equal to the long-time active diffusivity of the particle. As expected in the absence of a magnetic field (α =0 ), the crossover time is equal to the characteristic time scale for rotational diffusion, τrot. In the presence of a magnetic field (α >0 ), the correlation function, the active diffusivity, and the crossover time decrease with increasing α . The magnetic field regulates the regimes of propulsion of the particle. Here, the field reduces the period of time at which the active particle undergoes a directional motion. Consequently, the active particle rapidly reaches a diffusive regime at τcross≪τrot . In the limit of weak fields (α ≪1 ), the crossover time decreases quadratically with α , while in the limit of strong fields (α ≫1 ) it decays asymptotically as α-1. The results are in excellent agreement with those obtained by Brownian dynamics

Update on the Mechanisms of Liver Regeneration.

PubMed

Preziosi, Morgan E; Monga, Satdarshan P

2017-05-01

Liver possesses many critical functions such as synthesis, detoxification, and metabolism. It continually receives nutrient-rich blood from gut, which incidentally is also toxin-rich. That may be why liver is uniquely bestowed with a capacity to regenerate. A commonly studied procedure to understand the cellular and molecular basis of liver regeneration is that of surgical resection. Removal of two-thirds of the liver in rodents or patients instigates alterations in hepatic homeostasis, which are sensed by the deficient organ to drive the restoration process. Although the exact mechanisms that initiate regeneration are unknown, alterations in hemodynamics and metabolism have been suspected as important effectors. Key signaling pathways are activated that drive cell proliferation in various hepatic cell types through autocrine and paracrine mechanisms. Once the prehepatectomy mass is regained, the process of regeneration is adequately terminated. This review highlights recent discoveries in the cellular and molecular basis of liver regeneration. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Advanced Active-Magnetic-Bearing Thrust-Measurement System

NASA Technical Reports Server (NTRS)

Imlach, Joseph; Kasarda, Mary; Blumber, Eric

2008-01-01

An advanced thrust-measurement system utilizes active magnetic bearings to both (1) levitate a floating frame in all six degrees of freedom and (2) measure the levitation forces between the floating frame and a grounded frame. This system was developed for original use in measuring the thrust exerted by a rocket engine mounted on the floating frame, but can just as well be used in other force-measurement applications. This system offers several advantages over prior thrust-measurement systems based on mechanical support by flexures and/or load cells: The system includes multiple active magnetic bearings for each degree of freedom, so that by selective use of one, some, or all of these bearings, it is possible to test a given article over a wide force range in the same fixture, eliminating the need to transfer the article to different test fixtures to obtain the benefit of full-scale accuracy of different force-measurement devices for different force ranges. Like other active magnetic bearings, the active magnetic bearings of this system include closed-loop control subsystems, through which the stiffness and damping characteristics of the magnetic bearings can be modified electronically. The design of the system minimizes or eliminates cross-axis force-measurement errors. The active magnetic bearings are configured to provide support against movement along all three orthogonal Cartesian axes, and such that the support along a given axis does not produce force along any other axis. Moreover, by eliminating the need for such mechanical connections as flexures used in prior thrust-measurement systems, magnetic levitation of the floating frame eliminates what would otherwise be major sources of cross-axis forces and the associated measurement errors. Overall, relative to prior mechanical-support thrust-measurement systems, this system offers greater versatility for adaptation to a variety of test conditions and requirements. The basic idea of most prior active-magnetic

Pulse-driven magnetoimpedance sensor detection of cardiac magnetic activity.

PubMed

Nakayama, Shinsuke; Sawamura, Kenta; Mohri, Kaneo; Uchiyama, Tsuyoshi

2011-01-01

This study sought to establish a convenient method for detecting biomagnetic activity in the heart. Electrical activity of the heart simultaneously induces a magnetic field. Detection of this magnetic activity will enable non-contact, noninvasive evaluation to be made. We improved the sensitivity of a pulse-driven magnetoimpedance (PMI) sensor, which is used as an electric compass in mobile phones and as a motion sensor of the operation handle in computer games, toward a pico-Tesla (pT) level, and measured magnetic fields on the surface of the thoracic wall in humans. The changes in magnetic field detected by this sensor synchronized with the electric activity of the electrocardiogram (ECG). The shape of the magnetic wave was largely altered by shifting the sensor position within 20 mm in parallel and/or perpendicular to the thoracic wall. The magnetic activity was maximal in the 4th intercostals near the center of the sterna. Furthermore, averaging the magnetic activity at 15 mm in the distance between the thoracic wall and the sensor demonstrated magnetic waves mimicking the P wave and QRS complex. The present study shows the application of PMI sensor in detecting cardiac magnetic activity in several healthy subjects, and suggests future applications of this technology in medicine and biology.

Thrombospondin-1 is a novel negative regulator of liver regeneration after partial hepatectomy through transforming growth factor-beta1 activation in mice.

PubMed

Hayashi, Hiromitsu; Sakai, Keiko; Baba, Hideo; Sakai, Takao

2012-05-01

The matricellular protein, thrombospondin-1 (TSP-1), is prominently expressed during tissue repair. TSP-1 binds to matrix components, proteases, cytokines, and growth factors and activates intracellular signals through its multiple domains. TSP-1 converts latent transforming growth factor-beta1 (TGF-β1) complexes into their biologically active form. TGF-β plays significant roles in cell-cycle regulation, modulation of differentiation, and induction of apoptosis. Although TGF-β1 is a major inhibitor of proliferation in cultured hepatocytes, the functional requirement of TGF-β1 during liver regeneration remains to be defined in vivo. We generated a TSP-1-deficient mouse model of a partial hepatectomy (PH) and explored TSP-1 induction, progression of liver regeneration, and TGF-β-mediated signaling during the repair process after hepatectomy. We show here that TSP-1-mediated TGF-β1 activation plays an important role in suppressing hepatocyte proliferation. TSP-1 expression was induced in endothelial cells (ECs) as an immediate early gene in response to PH. TSP-1 deficiency resulted in significantly reduced TGF-β/Smad signaling and accelerated hepatocyte proliferation through down-regulation of p21 protein expression. TSP-1 induced in ECs by reactive oxygen species (ROS) modulated TGF-β/Smad signaling and proliferation in hepatocytes in vitro, suggesting that the immediately and transiently produced ROS in the regenerating liver were the responsible factor for TSP-1 induction. We have identified TSP-1 as an inhibitory element in regulating liver regeneration by TGF-β1 activation. Our work defines TSP-1 as a novel immediate early gene that could be a potential therapeutic target to accelerate liver regeneration. Copyright © 2011 American Association for the Study of Liver Diseases.

NEUROTROPHIC FACTORS IN COMBINATORIAL APPROACHES FOR SPINAL CORD REGENERATION

PubMed Central

McCall, Julianne; Weidner, Norbert; Blesch, Armin

2012-01-01

Axonal regeneration is inhibited by a plethora of different mechanisms in the adult central nervous system (CNS). While neurotrophic factors have been shown to stimulate axonal growth in numerous animal models of nervous system injury, a lack of suitable growth substrates, an insufficient activation of neuron-intrinsic regenerative programs and extracellular inhibitors of regeneration limit the efficacy of neurotrophic factor delivery for anatomical and functional recovery after spinal cord injury. Thus, growth-stimulating factors will likely have to be combined with other treatment approaches to tap into the full potential of growth factor therapy for axonal regeneration. In addition, the temporal and spatial distribution of growth factors have to be tightly controlled to achieve biologically active concentrations, to allow for the chemotropic guidance of axons and to prevent adverse effects related to the widespread distribution of neurotrophic factors. Here, we will review the rationale for combinatorial treatments in axonal regeneration and summarize some recent progress in promoting axonal regeneration in the injured CNS using such approaches. PMID:22526621

Regulation of zebrafish heart regeneration by miR-133.

PubMed

Yin, Viravuth P; Lepilina, Alexandra; Smith, Ashley; Poss, Kenneth D

2012-05-15

Zebrafish regenerate cardiac muscle after severe injuries through the activation and proliferation of spared cardiomyocytes. Little is known about factors that control these events. Here we investigated the extent to which miRNAs regulate zebrafish heart regeneration. Microarray analysis identified many miRNAs with increased or reduced levels during regeneration. miR-133, a miRNA with known roles in cardiac development and disease, showed diminished expression during regeneration. Induced transgenic elevation of miR-133 levels after injury inhibited myocardial regeneration, while transgenic miR-133 depletion enhanced cardiomyocyte proliferation. Expression analyses indicated that cell cycle factors mps1, cdc37, and PA2G4, and cell junction components cx43 and cldn5, are miR-133 targets during regeneration. Using pharmacological inhibition and EGFP sensor interaction studies, we found that cx43 is a new miR-133 target and regeneration gene. Our results reveal dynamic regulation of miRNAs during heart regeneration, and indicate that miR-133 restricts injury-induced cardiomyocyte proliferation. Copyright © 2012. Published by Elsevier Inc.

Regulation of zebrafish heart regeneration by miR-133

PubMed Central

Yin, Viravuth P.; Lepilina, Alexandra; Smith, Ashley; Poss, Kenneth D.

2012-01-01

Zebrafish regenerate cardiac muscle after severe injuries through the activation and proliferation of spared cardiomyocytes. Little is known about factors that control these events. Here we investigated the extent to which miRNAs regulate zebrafish heart regeneration. Microarray analysis identified many miRNAs with increased or reduced levels during regeneration. miR-133, a miRNA with known roles in cardiac development and disease, showed diminished expression during regeneration. Induced transgenic elevation of miR-133 levels after injury inhibited myocardial regeneration, while transgenic miR-133 depletion enhanced cardiomyocyte proliferation. Expression analyses indicated that cell cycle factors mps1, cdc37, and PA2G4, and cell junction components cx43 and cldn5, are miR-133 targets during regeneration. With pharmacological inhibition and EGFP sensor interaction studies, we demonstrated that cx43 is a new miR-133 target and regeneration gene. Our results reveal dynamic regulation of miRNAs during heart regeneration, and indicate that miR-133 restricts injury-induced cardiomyocyte proliferation. PMID:22374218

Reduce, reuse, recycle - Developmental signals in spinal cord regeneration.

PubMed

Cardozo, Marcos Julian; Mysiak, Karolina S; Becker, Thomas; Becker, Catherina G

2017-12-01

Anamniotes, fishes and amphibians, have the capacity to regenerate spinal cord tissue after injury, generating new neurons that mature and integrate into the spinal circuitry. Elucidating the molecular signals that promote this regeneration is a fundamental question in regeneration research. Model systems, such as salamanders and larval and adult zebrafish are used to analyse successful regeneration. This shows that many developmental signals, such as Notch, Hedgehog (Hh), Bone Morphogenetic Protein (BMP), Wnt, Fibroblast Growth Factor (FGF), Retinoic Acid (RA) and neurotransmitters are redeployed during regeneration and activate resident spinal progenitor cells. Here we compare the roles of these signals in spinal cord development and regeneration of the much larger and fully patterned adult spinal cord. Understanding how developmental signalling systems are reactivated in successfully regenerating species may ultimately lead to ways to reactivate similar systems in mammalian progenitor cells, which do not show neurogenesis after spinal injury. Copyright © 2017. Published by Elsevier Inc.

The Magnetic Origins of Solar Activity

NASA Technical Reports Server (NTRS)

Antiochos, S. K.

2012-01-01

The defining physical property of the Sun's corona is that the magnetic field dominates the plasma. This property is the genesis for all solar activity ranging from quasi-steady coronal loops to the giant magnetic explosions observed as coronal mass ejections/eruptive flares. The coronal magnetic field is also the fundamental driver of all space weather; consequently, understanding the structure and dynamics of the field, especially its free energy, has long been a central objective in Heliophysics. The main obstacle to achieving this understanding has been the lack of accurate direct measurements of the coronal field. Most attempts to determine the magnetic free energy have relied on extrapolation of photospheric measurements, a notoriously unreliable procedure. In this presentation I will discuss what measurements of the coronal field would be most effective for understanding solar activity. Not surprisingly, the key process for driving solar activity is magnetic reconnection. I will discuss, therefore, how next-generation measurements of the coronal field will allow us to understand not only the origins of space weather, but also one of the most important fundamental processes in cosmic and laboratory plasmas.

Magnetic activity of surface plasmon resonance using dielectric magnetic materials fabricated on quartz glass substrate

NASA Astrophysics Data System (ADS)

Narushima, Kazuki; Ashizawa, Yoshito; Brachwitz, Kerstin; Hochmuth, Holger; Lorenz, Michael; Grundmann, Marius; Nakagawa, Katsuji

2016-07-01

The magnetic activity of surface plasmons in Au/MFe2O4 (M = Ni, Co, and Zn) polycrystalline bilayer films fabricated on a quartz glass substrate was studied for future magnetic sensor applications using surface plasmon resonance. The excitation of surface plasmons and their magnetic activity were observed in all investigated Au/MFe2O4 films. The magnetic activity of surface plasmons of the polycrystalline Au/NiFe2O4 film was larger than those of the other polycrystalline Au/MFe2O4 films, the epitaxial NiFe2O4 film, and metallic films. The large magnetic activity of surface plasmons of the polycrystalline film is controlled by manipulating surface plasmon excitation conditions and magnetic properties.

A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration.

PubMed

Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

2015-01-01

New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days' implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days' implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration.

Optimization of Regenerators for AMRR Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nellis, Gregory; Klein, Sanford; Brey, William

Active Magnetic Regenerative Refrigeration (AMRR) systems have no direct global warming potential or ozone depletion potential and hold the potential for providing refrigeration with efficiencies that are equal to or greater than the vapor compression systems used today. The work carried out in this project has developed and improved modeling tools that can be used to optimize and evaluate the magnetocaloric materials and geometric structure of the regenerator beds required for AMRR Systems. There has been an explosion in the development of magnetocaloric materials for AMRR systems over the past few decades. The most attractive materials, based on the magnitudemore » of the measured magnetocaloric effect, tend to also have large amounts of hysteresis. This project has provided for the first time a thermodynamically consistent method for evaluating these hysteretic materials in the context of an AMRR cycle. An additional, practical challenge that has been identified for AMRR systems is related to the participation of the regenerator wall in the cyclic process. The impact of housing heat capacity on both passive and active regenerative systems has been studied and clarified within this project. This report is divided into two parts corresponding to these two efforts. Part 1 describes the work related to modeling magnetic hysteresis while Part 2 discusses the modeling of the heat capacity of the housing. A key outcome of this project is the development of a publically available modeling tool that allows researchers to identify a truly optimal magnetocaloric refrigerant. Typically, the refrigeration potential of a magnetocaloric material is judged entirely based on the magnitude of the magnetocaloric effect and other properties of the material that are deemed unimportant. This project has shown that a material with a large magnetocaloric effect (as evidenced, for example, by a large adiabatic temperature change) may not be optimal when it is accompanied by a large

B cell-mediated maintenance of CD169+ cells is critical for liver regeneration.

PubMed

Behnke, Kristina; Zhuang, Yuan; Xu, Haifeng C; Sundaram, Balamurugan; Reich, Maria; Shinde, Prashant V; Huang, Jun; Modares, Nastaran Fazel; Tumanov, Alexei V; Polz, Robin; Scheller, Jürgen; Ware, Carl F; Pfeffer, Klaus; Keitel, Verena; Häussinger, Dieter; Pandyra, Aleksandra A; Lang, Karl S; Lang, Philipp A

2018-05-09

The liver has an extraordinary capacity to regenerate via activation of key molecular pathways. However, central regulators controlling liver regeneration remain insufficiently studied. Here we show that B cell-deficient animals failed to induce sufficient liver regeneration after partial hepatectomy (PHx). Consistently, adoptive transfer of B cells could rescue defective liver regeneration. B cell mediated lymphotoxin beta production promoted recovery from PHx. Absence of B cells coincided with loss of splenic CD169 + macrophages. Moreover, depletion of CD169 + cells resulted in defective liver regeneration and decreased survival, which was associated with reduced hepatocyte proliferation. Mechanistically, CD169 + cells contributed to liver regeneration by inducing hepatic IL-6 production and STAT3 activation. Accordingly, treatment of CD169 + cell depleted animals with IL-6/Il-6R rescued liver regeneration and severe pathology following PHx. In conclusion, we identified CD169 + cells to be a central trigger for liver regeneration, by inducing key signaling pathways important for liver regeneration. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.

miR-378 attenuates muscle regeneration by delaying satellite cell activation and differentiation in mice.

PubMed

Zeng, Ping; Han, Wanhong; Li, Changyin; Li, Hu; Zhu, Dahai; Zhang, Yong; Liu, Xiaohong

2016-09-01

Skeletal muscle mass and homeostasis during postnatal muscle development and regeneration largely depend on adult muscle stem cells (satellite cells). We recently showed that global overexpression of miR-378 significantly reduced skeletal muscle mass in mice. In the current study, we used miR-378 transgenic (Tg) mice to assess the in vivo functional effects of miR-378 on skeletal muscle growth and regeneration. Cross-sectional analysis of skeletal muscle tissues showed that the number and size of myofibers were significantly lower in miR-378 Tg mice than in wild-type mice. Attenuated cardiotoxin-induced muscle regeneration in miR-378 Tg mice was found to be associated with delayed satellite cell activation and differentiation. Mechanistically, miR-378 was found to directly target Igf1r in muscle cells both in vitro and in vivo These miR-378 Tg mice may provide a model for investigating the physiological and pathological roles of skeletal muscle in muscle-associated diseases in humans, particularly in sarcopenia. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A rapid and efficient in vitro regeneration system for lettuce (Lactuca sativa L.).

PubMed

Armas, Isabel; Pogrebnyak, Natalia; Raskin, Ilya

2017-01-01

Successful biotechnological improvement of crop plants requires a reliable and efficient in vitro regeneration system. Lettuce ( Lactuca sativa L.), one the most important vegetable crops worldwide, is strongly genotype-dependent in terms of regeneration capacity, limiting the potential for biotechnological improvement of cultivars which show recalcitrance under currently available protocols. The effect of different nutrient sources, plant hormone combinations and activated charcoal supplementation on shoot induction efficiency was evaluated on the cultivar 'RSL NFR', which had previously shown poor regeneration efficiency. Multiple shoot organogenesis from cotyledon explants was recorded at the highest frequency and speed on Murashige and Skoog regeneration medium supplemented with 200 mg/l of activated charcoal, 3% sucrose, 10 mg/l benzylaminopurine and 0.5 mg/l naphthaleneacetic acid, which induced shoots through direct regeneration in 90.8 ± 7.9% of explants. High shoot induction efficiency was also observed, albeit not quantified, when using this medium on some other cultivars. This activated charcoal-containing regeneration medium might offer a rapid and efficient option for direct shoot induction in some lettuce genotypes that do not respond well to common lettuce regeneration protocols. This is also the first report of the effect of activated charcoal in lettuce tissue culture.

MicroRNA-155 facilitates skeletal muscle regeneration by balancing pro- and anti-inflammatory macrophages

PubMed Central

Nie, M; Liu, J; Yang, Q; Seok, H Y; Hu, X; Deng, Z-L; Wang, D-Z

2016-01-01

Skeletal muscle has remarkable regeneration capacity and regenerates in response to injury. Muscle regeneration largely relies on muscle stem cells called satellite cells. Satellite cells normally remain quiescent, but in response to injury or exercise they become activated and proliferate, migrate, differentiate, and fuse to form multinucleate myofibers. Interestingly, the inflammatory process following injury and the activation of the myogenic program are highly coordinated, with myeloid cells having a central role in modulating satellite cell activation and regeneration. Here, we show that genetic deletion of microRNA-155 (miR-155) in mice substantially delays muscle regeneration. Surprisingly, miR-155 does not appear to directly regulate the proliferation or differentiation of satellite cells. Instead, miR-155 is highly expressed in myeloid cells, is essential for appropriate activation of myeloid cells, and regulates the balance between pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages during skeletal muscle regeneration. Mechanistically, we found that miR-155 suppresses SOCS1, a negative regulator of the JAK-STAT signaling pathway, during the initial inflammatory response upon muscle injury. Our findings thus reveal a novel role of miR-155 in regulating initial immune responses during muscle regeneration and provide a novel miRNA target for improving muscle regeneration in degenerative muscle diseases. PMID:27277683

Assessing regeneration potential

Treesearch

Ivan L. Sander

1989-01-01

When a regeneration harvest cut is planned for even-aged stands or it is time to make another cut in uneven-aged stands, the first thing to do is assess the regeneration potential. Regeneration potential is the likelihood of being successful in reproducing desired species. You need an assessment to be reasonably sure that regeneration and management objectives can be...

Axon Regeneration Genes Identified by RNAi Screening in C. elegans

PubMed Central

Nix, Paola; Hammarlund, Marc; Hauth, Linda; Lachnit, Martina; Jorgensen, Erik M.

2014-01-01

Axons of the mammalian CNS lose the ability to regenerate soon after development due to both an inhibitory CNS environment and the loss of cell-intrinsic factors necessary for regeneration. The complex molecular events required for robust regeneration of mature neurons are not fully understood, particularly in vivo. To identify genes affecting axon regeneration in Caenorhabditis elegans, we performed both an RNAi-based screen for defective motor axon regeneration in unc-70/β-spectrin mutants and a candidate gene screen. From these screens, we identified at least 50 conserved genes with growth-promoting or growth-inhibiting functions. Through our analysis of mutants, we shed new light on certain aspects of regeneration, including the role of β-spectrin and membrane dynamics, the antagonistic activity of MAP kinase signaling pathways, and the role of stress in promoting axon regeneration. Many gene candidates had not previously been associated with axon regeneration and implicate new pathways of interest for therapeutic intervention. PMID:24403161

Photospheric Magnetic Evolution in the WHI Active Regions

NASA Technical Reports Server (NTRS)

Welsch, B. T.; McTiernan, J. M.; Christe, S.

2012-01-01

Sequences of line-of-sight (LOS) magnetograms recorded by the Michelson Doppler Imager are used to quantitatively characterize photospheric magnetic structure and evolution in three active regions that rotated across the Sun s disk during the Whole Heliosphere Interval (WHI), in an attempt to relate the photospheric magnetic properties of these active regions to flares and coronal mass ejections (CMEs). Several approaches are used in our analysis, on scales ranging from whole active regions, to magnetic features, to supergranular scales, and, finally, to individual pixels. We calculated several parameterizations of magnetic structure and evolution that have previously been associated with flare and CME activity, including total unsigned magnetic flux, magnetic flux near polarity-inversion lines, amount of canceled flux, the "proxy Poynting flux," and helicity flux. To catalog flare events, we used flare lists derived from both GOES and RHESSI observations. By most such measures, AR 10988 should have been the most flare- and CME-productive active region, and AR 10989 the least. Observations, however, were not consistent with this expectation: ARs 10988 and 10989 produced similar numbers of flares, and AR 10989 also produced a few CMEs. These results highlight present limitations of statistics-based flare and CME forecasting tools that rely upon line-of-sight photospheric magnetic data alone.

The cancer paradigms of mammalian regeneration: can mammals regenerate as amphibians?

PubMed

Sarig, Rachel; Tzahor, Eldad

2017-04-01

Regeneration in mammals is restricted to distinct tissues and occurs mainly by expansion and maturation of resident stem cells. During regeneration, even subtle mutations in the proliferating cells may cause a detrimental effect by eliciting abnormal differentiation or malignant transformation. Indeed, cancer in mammals has been shown to arise through deregulation of stem cells maturation, which often leads to a differentiation block and cell transformation. In contrast, lower organisms such as amphibians retain a remarkable regenerative capacity in various organs, which occurs via de- and re-differentiation of mature cells. Interestingly, regenerating amphibian cells are highly resistant to oncogenic transformation. Therapeutic approaches to improve mammalian regeneration mainly include stem-cell transplantations; but, these have proved unsuccessful in non-regenerating organs such as the heart. A recently developed approach is to induce de-differentiation of mature cardiomyocytes using factors that trigger their re-entry into the cell cycle. This novel approach raises numerous questions regarding the balance between transformation and regeneration induced by de-differentiation of mature mammalian somatic cells. Can this balance be controlled artificially? Do de-differentiated cells acquire the protection mechanisms seen in regenerating cells of lower organisms? Is this model unique to the cardiac tissue, which rarely develops tumors? This review describes regeneration processes in both mammals and lower organisms and, particularly, the ability of regenerating cells to avoid transformation. By comparing the characteristics of mammalian embryonic and somatic cells, we discuss therapeutic strategies of using various cell populations for regeneration. Finally, we describe a novel cardiac regeneration approach and its implications for regenerative medicine. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email

Pharmacologically inhibiting kinesin-5 activity with monastrol promotes axonal regeneration following spinal cord injury

PubMed Central

Xu, Chen; Klaw, Michelle C.; Lemay, Michel A.; Baas, Peter W.; Tom, Veronica J.

2014-01-01

While it is well established that the axons of adult neurons have a lower capacity for regrowth, some regeneration of certain CNS populations after spinal cord injury (SCI) is possible if their axons are provided with a permissive substrate, such as an injured peripheral nerve. While some axons readily regenerate into a peripheral nerve graft (PNG), these axons almost always stall at the distal interface and fail to re-innervate spinal cord tissue. Treatment of the glial scar at the distal graft interface with chondroitinase ABC (ChABC) can improve regeneration, but most regenerated axons need further stimulation to extend beyond the interface. Previous studies demonstrate that pharmacologically inhibiting kinesin-5, a motor protein best known for its essential role in mitosis but also expressed in neurons, with the pharmacological agent monastrol increases axon growth on inhibitory substrates in vitro. We sought to determine if monastrol treatment after a SCI improves functional axon regeneration. Animals received complete thoracic level 7 (T7) transections and PNGs and were treated intrathecally with ChABC and either monastrol or DMSO vehicle. We found that combining ChABC with monastrol significantly enhanced axon regeneration. However, there were no further improvements in function or enhanced c-Fos induction upon stimulation of spinal cord rostral to the transection. This indicates that monastrol improves ChABC-mediated axon regeneration but that further treatments are needed to enhance the integration of these regrown axons. PMID:25447935

Magnetic structure of an activated filament in a flaring active region

NASA Astrophysics Data System (ADS)

Sasso, C.; Lagg, A.; Solanki, S. K.

2014-01-01

Aims: While the magnetic field in quiescent prominences has been widely investigated, less is known about the field in activated prominences. We report observational results on the magnetic field structure of an activated filament in a flaring active region. In particular, we studied its magnetic structure and line-of-sight flows during its early activated phase, shortly before it displayed signs of rotation. Methods: We inverted the Stokes profiles of the chromospheric He i 10 830 Å triplet and the photospheric Si i 10 827 Å line observed in this filament by the Vacuum Tower Telescope on Tenerife. Using these inversion results, we present and interpret the first maps of the velocity and magnetic field obtained in an activated filament, both in the photosphere and the chromosphere. Results: Up to five different magnetic components are found in the chromospheric layers of the filament, while outside the filament a single component is sufficient to reproduce the observations. Magnetic components displaying an upflow are preferentially located towards the centre of the filament, while the downflows are concentrated along its periphery. Moreover, the upflowing gas is associated with an opposite-polarity magnetic configuration with respect to the photosphere, while the downflowing gas is associated with a same-polarity configuration. Conclusions: The activated filament has a very complex structure. Nonetheless, it is compatible with a flux rope, albeit a distorted one, in the normal configuration. The observations are best explained by a rising flux rope in which part of the filament material is still stably stored (upflowing material, rising with the field), while the rest is no longer stably stored and flows down along the field lines. The movie is available in electronic form at http://www.aanda.org

Activity Analyses for Solar-type Stars Observed with Kepler. II. Magnetic Feature versus Flare Activity

NASA Astrophysics Data System (ADS)

He, Han; Wang, Huaning; Zhang, Mei; Mehrabi, Ahmad; Yan, Yan; Yun, Duo

2018-05-01

The light curves of solar-type stars present both periodic fluctuation and flare spikes. The gradual periodic fluctuation is interpreted as the rotational modulation of magnetic features on the stellar surface and is used to deduce magnetic feature activity properties. The flare spikes in light curves are used to derive flare activity properties. In this paper, we analyze the light curve data of three solar-type stars (KIC 6034120, KIC 3118883, and KIC 10528093) observed with Kepler space telescope and investigate the relationship between their magnetic feature activities and flare activities. The analysis shows that: (1) both the magnetic feature activity and the flare activity exhibit long-term variations as the Sun does; (2) unlike the Sun, the long-term variations of magnetic feature activity and flare activity are not in phase with each other; (3) the analysis of star KIC 6034120 suggests that the long-term variations of magnetic feature activity and flare activity have a similar cycle length. Our analysis and results indicate that the magnetic features that dominate rotational modulation and the flares possibly have different source regions, although they may be influenced by the magnetic field generated through a same dynamo process.

Magnetic resonance imaging appearance of oxidized regenerated cellulose in breast cancer surgery.

PubMed

Giuliani, Michela; Rella, Rossella; Fubelli, Rita; Patrolecco, Federica; Di Giovanni, Silvia Eleonora; Buccheri, Chiara; Padovano, Federico; Belli, Paolo; Romani, Maurizio; Rinaldi, Pierluigi; Bufi, Enida; Franceschini, Gianluca; Bonomo, Lorenzo

2016-09-01

To describe magnetic resonance imaging (MRI) findings in patients who underwent breast-conserving surgery followed by oxidized regenerated cellulose (ORC) implantation in surgical cavity. We retrospectively reviewed 51 MRI examinations performed between January 2009 and January 2014 in 51 patients who underwent BCS with ORC implantation. In 29/51 (57 %) cases, MRIs showed abnormal findings with three main MRI patterns: (1) complex masses: hyperintense collections on T2-weighted (w) images with internal round hypointense nodules without contrast enhancement (55 %); (2) completely hyperintense collections (17 %); and (3) completely hypointense lesions (28 %). All lesions showed rim enhancement on T1w images obtained in the late phase of the dynamic study with a type 1 curve. Diffusion-weighted imaging was negative in all MRIs and, in particular, 22/29 (76 %) lesions were hyperintense but showing ADC values >1.4 × 10(-3) mm(2)/s, while the remaining 7/29 (24 %) lesions were hypointense. In four cases, linear non-mass-like enhancement was detected at the periphery of surgical cavity; these patients were addressed to a short-term follow-up, and the subsequent examinations showed the resolution of these findings. When applied to surgical residual cavity, ORC can lead alterations in surgical scar. This could induce radiologists to misinterpret ultrasonographic and mammographic findings, addressing patients to MRI or biopsy; so knowledge of MRI specific features of ORC, it is essential to avoid misdiagnosis of recurrence.

Emissions During and Real-world Frequency of Heavy-duty Diesel Particulate Filter Regeneration.

PubMed

Ruehl, Chris; Smith, Jeremy D; Ma, Yilin; Shields, Jennifer Erin; Burnitzki, Mark; Sobieralski, Wayne; Ianni, Robert; Chernich, Donald J; Chang, M-C Oliver; Collins, John Francis; Yoon, Seungju; Quiros, David; Hu, Shaohua; Dwyer, Harry

2018-05-15

Recent tightening of particulate matter (PM) emission standards for heavy-duty engines has spurred the widespread adoption of diesel particulate filters (DPFs), which need to be regenerated periodically to remove trapped PM. The total impact of DPFs therefore depends not only on their filtering efficiency during normal operation, but also on the emissions during and the frequency of regeneration events. We performed active (parked and driving) and passive regenerations on two heavy-duty diesel vehicles (HDDVs), and report the chemical composition of emissions during these events, as well as the efficiency with which trapped PM is converted to gas-phase products. We also collected activity data from 85 HDDVs to determine how often regeneration occurs during real-world operation. PM emitted during regeneration ranged from 0.2 to 16.3 g, and the average time and distance between real-world active regenerations was 28.0 h and 599 miles. These results indicate that regeneration of real-world DPFs does not substantially offset the reduction of PM by DPFs during normal operation. The broad ranges of regeneration frequency per truck (3-100 h and 23-4078 miles) underscore the challenges in designing engines and associated aftertreatments that reduce emissions for all real-world duty cycles.

De Novo Kidney Regeneration with Stem Cells

PubMed Central

Yokote, Shinya; Yamanaka, Shuichiro; Yokoo, Takashi

2012-01-01

Recent studies have reported on techniques to mobilize and activate endogenous stem-cells in injured kidneys or to introduce exogenous stem cells for tissue repair. Despite many recent advantages in renal regenerative therapy, chronic kidney disease (CKD) remains a major cause of morbidity and mortality and the number of CKD patients has been increasing. When the sophisticated structure of the kidneys is totally disrupted by end stage renal disease (ESRD), traditional stem cell-based therapy is unable to completely regenerate the damaged tissue. This suggests that whole organ regeneration may be a promising therapeutic approach to alleviate patients with uncured CKD. We summarize here the potential of stem-cell-based therapy for injured tissue repair and de novo whole kidney regeneration. In addition, we describe the hurdles that must be overcome and possible applications of this approach in kidney regeneration. PMID:23251079

Intrahepatic T cell receptor β immune repertoire is essential for liver regeneration.

PubMed

Liang, Qing; Liu, Zeyuan; Zhu, Chao; Wang, Bin; Liu, Xiaoke; Yang, Yanan; Lv, Xue; Mu, Haiyu; Wang, Kejia

2018-04-27

T lymphocytes synergize with the cellular immune system to promote hepatocyte regeneration. The T cell receptor (TCR) immune repertoire is closely associated with the host immune response and regenerative proliferation. High-throughput sequencing of TCR provides deep insight into monitoring the immune microenvironment. Here, we aimed to determine the role of the TCRβ immune repertoire in liver regeneration. We investigated the hepatic regeneration in TCRβ chain-deficient (Tcrb -/- ) mice by two-thirds partial hepatectomy (PHx) method. Our results demonstrated that Tcrb -/- mice revealed a reduced capacity for liver regeneration, which was characterized by impaired hepatocyte proliferation and enhanced hepatocyte apoptosis. Dysregulation of inflammatory signalling activation and inflammatory factors was observed in regenerated Tcrb -/- livers. Simultaneously, significantly altered immunocyte levels and aberrant cytokine levels were observed during hepatic regeneration. In addition, we first determined the profile of the TCRβ immune repertoire during liver regeneration, indicating that PHx resulted in remarkably lower TCRβ diversity in intrahepatic T lymphocytes. Taken together, our data suggest that TCRβ deficiency gives a rise to aberrant intrahepatic immune microenvironment that impairs liver regeneration, and the TCRβ reconstitution is required for hepatic immunocyte recruitment and activation during liver regeneration. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.

Regeneration of guinea PIG facial nerve: the effect of hypergravity

NASA Astrophysics Data System (ADS)

Rosenzweig, E.; Horodiceanu, E.; Ishay, J. S.

Exposure to moderate hypergravity improves the regenerative capacity of sectioned guinea-pig facial nerve. The improvement in regeneration is tri-directional as follows: a) an average 1.7 fold increase in rate of regeneration in guinea pigs subjected to hypergravity; b) a 25% enhancement of facial muscle activity following the exposure to hypergravity; and c) improvement in the quality of regeneration from an esthetic standpoint. A good correlation was recorded between the histological structure of the severed nerve at the end of the regeneration and the clinical results.

Oligodendrocyte Regeneration and CNS Remyelination Require TACE/ADAM17.

PubMed

Palazuelos, Javier; Klingener, Michael; Raines, Elaine W; Crawford, Howard C; Aguirre, Adan

2015-09-02

The identification of the molecular network that supports oligodendrocyte (OL) regeneration under demyelinating conditions has been a primary goal for regenerative medicine in demyelinating disorders. We recently described an essential function for TACE/ADAM17 in regulating oligodendrogenesis during postnatal myelination, but it is unknown whether this protein also plays a role in OL regeneration and remyelination under demyelinating conditions. By using genetic mouse models to achieve selective gain- or loss-of-function of TACE or EGFR in OL lineage cells in vivo, we found that TACE is critical for EGFR activation in OLs following demyelination, and therefore, for sustaining OL regeneration and CNS remyelination. TACE deficiency in oligodendrocyte progenitor cells following demyelination disturbs OL lineage cell expansion and survival, leading to a delay in the remyelination process. EGFR overexpression in TACE deficient OLs in vivo restores OL development and postnatal CNS myelination, but also OL regeneration and CNS remyelination following demyelination. Our study reveals an essential function of TACE in supporting OL regeneration and CNS remyelination that may contribute to the design of new strategies for therapeutic intervention in demyelinating disorders by promoting oligodendrocyte regeneration and myelin repair. Oligodendrocyte (OL) regeneration has emerged as a promising new approach for the treatment of demyelinating disorders. By using genetic mouse models to selectively delete TACE expression in oligodendrocyte progenitors cells (OPs), we found that TACE/ADAM17 is required for supporting OL regeneration following demyelination. TACE genetic depletion in OPs abrogates EGFR activation in OL lineage cells, and perturbs cell expansion and survival, blunting the process of CNS remyelination. Moreover, EGFR overexpression in TACE-deficient OPs in vivo overcomes the defects in OL development during postnatal development but also OL regeneration during CNS

Magnetic refrigeration for low-temperature applications

NASA Technical Reports Server (NTRS)

Barclay, J. A.

1985-01-01

The application of refrigeration at low temperatures ranging from production of liquid helium for medical imaging systems to cooling of infrared sensors on surveillance satellites is discussed. Cooling below about 15 K with regenerative refrigerators is difficult because of the decreasing thermal mass of the regenerator compared to that of the working material. In order to overcome this difficulty with helium gas as the working material, a heat exchanger plus a Joule-Thomson or other exponder is used. Regenerative magnetic refrigerators with magnetic solids as the working material have the same regenerator problem as gas refrigerators. This problem provides motivation for the development of nonregenerative magnetic refrigerators that span approximately 1 K to approximately 0 K. Particular emphasis is placed on high reliability and high efficiency. Calculations indicate considerable promise in this area. The principles, the potential, the problems, and the progress towards development of successful 4 to 20 K magnetic refrigerators are discussed.

A biochemical basis for induction of retina regeneration by antioxidants.

PubMed

Echeverri-Ruiz, Nancy; Haynes, Tracy; Landers, Joseph; Woods, Justin; Gemma, Michael J; Hughes, Michael; Del Rio-Tsonis, Katia

2018-01-15

The use of antioxidants in tissue regeneration has been studied, but their mechanism of action is not well understood. Here, we analyze the role of the antioxidant N-acetylcysteine (NAC) in retina regeneration. Embryonic chicks are able to regenerate their retina after its complete removal from retinal stem/progenitor cells present in the ciliary margin (CM) of the eye only if a source of exogenous factors, such as FGF2, is present. This study shows that NAC modifies the redox status of the CM, initiates self-renewal of the stem/progenitor cells, and induces regeneration in the absence of FGF2. NAC works as an antioxidant by scavenging free radicals either independently or through the synthesis of glutathione (GSH), and/or by reducing oxidized proteins through a thiol disulfide exchange activity. We dissected the mechanism used by NAC to induce regeneration through the use of inhibitors of GSH synthesis and the use of other antioxidants with different biochemical structures and modes of action, and found that NAC induces regeneration through its thiol disulfide exchange activity. Thus, our results provide, for the first time, a biochemical basis for induction of retina regeneration. Furthermore, NAC induction was independent of FGF receptor signaling, but dependent on the MAPK (pErk1/2) pathway. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Protein tyrosine phosphatase of liver regeneration-1 is required for normal timing of cell cycle progression during liver regeneration

PubMed Central

Jiao, Yang; Ye, Diana Z.; Li, Zhaoyu; Teta-Bissett, Monica; Peng, Yong; Taub, Rebecca; Greenbaum, Linda E.

2014-01-01

Protein tyrosine phosphatase of liver regeneration-1 (Prl-1) is an immediate-early gene that is significantly induced during liver regeneration. Several in vitro studies have suggested that Prl-1 is important for the regulation of cell cycle progression. To evaluate its function in liver regeneration, we ablated the Prl-1 gene specifically in mouse hepatocytes using the Cre-loxP system. Prl-1 mutant mice (Prl-1loxP/loxP;AlfpCre) appeared normal and fertile. Liver size and metabolic function in Prl-1 mutants were comparable to controls, indicating that Prl-1 is dispensable for liver development, postnatal growth, and hepatocyte differentiation. Mutant mice demonstrated a delay in DNA synthesis after 70% partial hepatectomy, although ultimate liver mass restoration was not affected. At 40 h posthepatectomy, reduced protein levels of the cell cycle regulators cyclin E, cyclin A2, cyclin B1, and cyclin-dependent kinase 1 were observed in Prl-1 mutant liver. Investigation of the major signaling pathways involved in liver regeneration demonstrated that phosphorylation of protein kinase B (AKT) and signal transducer and activator of transcription (STAT) 3 were significantly reduced at 40 h posthepatectomy in Prl-1 mutants. Taken together, this study provides evidence that Prl-1 is required for proper timing of liver regeneration after partial hepatectomy. Prl-1 promotes G1/S progression via modulating expression of several cell cycle regulators through activation of the AKT and STAT3 signaling pathway. PMID:25377314

Regeneration

Treesearch

George A. Schier; Wayne D. Shepperd; John R. Jones

1985-01-01

There are basically two approaches to regenerating aspen stands-sexual reproduction using seed, or vegetative regeneration by root suckering. In the West, root suckering is the most practical method. The advantage of having an existing, well established root system capable of producing numerous root suckers easily outweighs natural or artificial reforestation in the...

Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication

PubMed Central

Mackey, Abigail L.; Rasmussen, Lotte K.; Kadi, Fawzi; Schjerling, Peter; Helmark, Ida C.; Ponsot, Elodie; Aagaard, Per; Durigan, João Luiz Q.; Kjaer, Michael

2016-01-01

With this study we investigated the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration. Young men ingested NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation–induced injury to the leg extensor muscles of one leg. Muscle biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR, and we also measured telomere length. After injury, and compared with PLA, IBU was found to augment the proportion of ActiveNotch1+ satellite cells at 2 d [IBU, 29 ± 3% vs. PLA, 19 ± 2% (means ± sem)], satellite cell content at 7 d [IBU, 0.16 ± 0.01 vs. PLA, 0.12 ± 0.01 (Pax7+ cells/fiber)], and to expedite muscle repair at 30 d. The PLA group displayed a greater proportion of embryonic myosin+ fibers and a residual ∼2-fold increase in mRNA levels of matrix proteins (all P < 0.05). Endomysial collagen was also elevated with PLA at 30 d. Minimum telomere length shortening was not observed. In conclusion, ingestion of NSAID has a potentiating effect on Notch activation of satellite cells and muscle remodeling during large-scale regeneration of injured human skeletal muscle.—Mackey, A. L., Rasmussen, L. K., Kadi, F., Schjerling, P., Helmark, I. C., Ponsot, E., Aagaard, P., Durigan, J. L. Q., Kjaer, M. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication. PMID:26936358

A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

PubMed Central

Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

2015-01-01

New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days’ implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration. PMID:25709432

Cell intrinsic control of axon regeneration

PubMed Central

Mar, Fernando M; Bonni, Azad; Sousa, Mónica M

2014-01-01

Although neurons execute a cell intrinsic program of axonal growth during development, following the establishment of connections, the developmental growth capacity declines. Besides environmental challenges, this switch largely accounts for the failure of adult central nervous system (CNS) axons to regenerate. Here, we discuss the cell intrinsic control of axon regeneration, including not only the regulation of transcriptional and epigenetic mechanisms, but also the modulation of local protein translation, retrograde and anterograde axonal transport, and microtubule dynamics. We further explore the causes underlying the failure of CNS neurons to mount a vigorous regenerative response, and the paradigms demonstrating the activation of cell intrinsic axon growth programs. Finally, we present potential mechanisms to support axon regeneration, as these may represent future therapeutic approaches to promote recovery following CNS injury and disease. PMID:24531721

Expressing Constitutively Active Rheb in Adult Neurons after a Complete Spinal Cord Injury Enhances Axonal Regeneration beyond a Chondroitinase-Treated Glial Scar

PubMed Central

Wu, Di; Klaw, Michelle C.; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E.

2015-01-01

After a spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to: (1) the presence of inhibitory molecules, e.g., chondroitin sulfate proteoglycans (CSPG), in the glial scar at the lesion; and (2) the diminished growth capacity of adult neurons. We sought to determine whether expressing a constitutively active form of the GTPase Rheb (caRheb) in adult neurons after a complete SCI in rats improves intrinsic growth potential to result in axon regeneration out of a growth-supportive peripheral nerve grafted (PNG) into the SCI cavity. We also hypothesized that treating the glial scar with chondroitinase ABC (ChABC), which digests CSPG, would further allow caRheb-transduced neurons to extend axons across the distal graft interface. We found that targeting this pathway at a clinically relevant post-SCI time point improves both sprouting and regeneration of axons. CaRheb increased the number of axons, but not the number of neurons, that projected into the PNG, indicative of augmented sprouting. We also saw that caRheb enhanced sprouting far rostral to the injury. CaRheb not only increased growth rostral and into the graft, it also resulted in significantly more regrowth of axons across a ChABC-treated scar into caudal spinal cord. CaRheb+ neurons had higher levels of growth-associated-43, suggestive of a newly identified mechanism for mTOR-mediated enhancement of regeneration. Thus, we demonstrate for the first time that simultaneously addressing intrinsic and scar-associated, extrinsic impediments to regeneration results in significant regrowth beyond an extremely challenging, complete SCI site. SIGNIFICANCE STATEMENT After spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to the diminished growth capacity of adult neurons and the presence of inhibitory molecules in the scar at the lesion. We sought to simultaneously counter both of these obstacles to achieve more robust

Expressing Constitutively Active Rheb in Adult Neurons after a Complete Spinal Cord Injury Enhances Axonal Regeneration beyond a Chondroitinase-Treated Glial Scar.

PubMed

Wu, Di; Klaw, Michelle C; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E; Tom, Veronica J

2015-08-05

After a spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to: (1) the presence of inhibitory molecules, e.g., chondroitin sulfate proteoglycans (CSPG), in the glial scar at the lesion; and (2) the diminished growth capacity of adult neurons. We sought to determine whether expressing a constitutively active form of the GTPase Rheb (caRheb) in adult neurons after a complete SCI in rats improves intrinsic growth potential to result in axon regeneration out of a growth-supportive peripheral nerve grafted (PNG) into the SCI cavity. We also hypothesized that treating the glial scar with chondroitinase ABC (ChABC), which digests CSPG, would further allow caRheb-transduced neurons to extend axons across the distal graft interface. We found that targeting this pathway at a clinically relevant post-SCI time point improves both sprouting and regeneration of axons. CaRheb increased the number of axons, but not the number of neurons, that projected into the PNG, indicative of augmented sprouting. We also saw that caRheb enhanced sprouting far rostral to the injury. CaRheb not only increased growth rostral and into the graft, it also resulted in significantly more regrowth of axons across a ChABC-treated scar into caudal spinal cord. CaRheb(+) neurons had higher levels of growth-associated-43, suggestive of a newly identified mechanism for mTOR-mediated enhancement of regeneration. Thus, we demonstrate for the first time that simultaneously addressing intrinsic and scar-associated, extrinsic impediments to regeneration results in significant regrowth beyond an extremely challenging, complete SCI site. After spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to the diminished growth capacity of adult neurons and the presence of inhibitory molecules in the scar at the lesion. We sought to simultaneously counter both of these obstacles to achieve more robust regeneration after

Active magnetic force microscopy of Sr-ferrite magnet by stimulating magnetization under an AC magnetic field: Direct observation of reversible and irreversible magnetization processes

NASA Astrophysics Data System (ADS)

Cao, Yongze; Kumar, Pawan; Zhao, Yue; Yoshimura, Satoru; Saito, Hitoshi

2018-05-01

Understanding the dynamic magnetization process of magnetic materials is crucial to improving their fundamental properties and technological applications. Here, we propose active magnetic force microscopy for observing reversible and irreversible magnetization processes by stimulating magnetization with an AC magnetic field based on alternating magnetic force microscopy with a sensitive superparamagnetic tip. This approach simultaneously measures sample's DC and AC magnetic fields. We used this microscopy approach to an anisotropic Sr-ferrite (SrF) sintered magnet. This is a single domain type magnet where magnetization mainly changes via magnetic rotation. The proposed method can directly observe the reversible and irreversible magnetization processes of SrF and clearly reveal magnetic domain evolution of SrF (without stimulating magnetization—stimulating reversible magnetization—stimulating irreversible magnetization switching) by slowly increasing the amplitude of the external AC magnetic field. This microscopy approach can evaluate magnetic inhomogeneity and explain the local magnetic process within the permanent magnet.

The Limit of Free Magnetic Energy in Active Regions

NASA Technical Reports Server (NTRS)

Moore, Ron; Falconer, David; Sterling, Alphonse

2012-01-01

By measuring from active-region magnetograms a proxy of the free energy in the active region fs magnetic field, it has been found previously that (1) there is an abrupt upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) the free energy is usually near its limit when the field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy ]limit line in (flux content, free-energy proxy) phase space. Here, from measurement of Marshall Space Flight Center vector magnetograms, we find the magnetic condition that underlies the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free ]energy proxy measured from vector magnetograms of 44 active regions, we find that (1) in active regions at and near their free ]energy limit, the ratio of magnetic-shear free energy to the non ]free magnetic energy the potential field would have is approximately 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. This shows that most active regions in which this core-field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1 or greater, most active regions are compelled to explode. From these results we surmise the magnetic condition that determines the free ]energy limit is the ratio of the free magnetic energy to the non-free energy the active region fs field would have were it completely relaxed to its potential ]field configuration, and that this ratio is approximately 1 at the free-energy limit and in the main sequence of explosive active regions.

Lens regeneration from the cornea requires suppression of Wnt/β-catenin signaling.

PubMed

Hamilton, Paul W; Sun, Yu; Henry, Jonathan J

2016-04-01

The frog, Xenopus laevis, possesses a high capacity to regenerate various larval tissues, including the lens, which is capable of complete regeneration from the cornea epithelium. However, the molecular signaling mechanisms of cornea-lens regeneration are not fully understood. Previous work has implicated the involvement of the Wnt signaling pathway, but molecular studies have been very limited. Iris-derived lens regeneration in the newt (Wolffian lens regeneration) has shown a necessity for active Wnt signaling in order to regenerate a new lens. Here we provide evidence that the Wnt signaling pathway plays a different role in the context of cornea-lens regeneration in Xenopus. We examined the expression of frizzled receptors and wnt ligands in the frog cornea epithelium. Numerous frizzled receptors (fzd1, fzd2, fzd3, fzd4, fzd6, fzd7, fzd8, and fzd10) and wnt ligands (wnt2b.a, wnt3a, wnt4, wnt5a, wnt5b, wnt6, wnt7b, wnt10a, wnt11, and wnt11b) are expressed in the cornea epithelium, demonstrating that this tissue is transcribing many of the ligands and receptors of the Wnt signaling pathway. When compared to flank epithelium, which is lens regeneration incompetent, only wnt11 and wnt11b are different (present only in the cornea epithelium), identifying them as potential regulators of cornea-lens regeneration. To detect changes in canonical Wnt/β-catenin signaling occurring within the cornea epithelium, axin2 expression was measured over the course of regeneration. axin2 is a well-established reporter of active Wnt/β-catenin signaling, and its expression shows a significant decrease at 24 h post-lentectomy. This decrease recovers to normal endogenous levels by 48 h. To test whether this signaling decrease was necessary for lens regeneration to occur, regenerating eyes were treated with either 6-bromoindirubin-3'-oxime (BIO) or 1-azakenpaullone - both activators of Wnt signaling - resulting in a significant reduction in the percentage of cases with successful

Activated macrophages create lineage-specific microenvironments for pancreatic acinar- and β-cell regeneration in mice.

PubMed

Criscimanna, Angela; Coudriet, Gina M; Gittes, George K; Piganelli, Jon D; Esni, Farzad

2014-11-01

Although the cells that contribute to pancreatic regeneration have been widely studied, little is known about the mediators of this process. During tissue regeneration, infiltrating macrophages debride the site of injury and coordinate the repair response. We investigated the role of macrophages in pancreatic regeneration in mice. We used a saporin-conjugated antibody against CD11b to reduce the number of macrophages in mice following diphtheria toxin receptor-mediated cell ablation of pancreatic cells, and evaluated the effects on pancreatic regeneration. We analyzed expression patterns of infiltrating macrophages after cell-specific injury or from the pancreas of nonobese diabetic mice. We developed an in vitro culture system to study the ability of macrophages to induce cell-specific regeneration. Depletion of macrophages impaired pancreatic regeneration. Macrophage polarization, as assessed by expression of tumor necrosis factor-α, interleukin 6, interleukin 10, and CD206, depended on the type of injury. The signals provided by polarized macrophages promoted lineage-specific generation of acinar or endocrine cells. Macrophage from nonobese diabetic mice failed to provide signals necessary for β-cell generation. Macrophages produce cell type-specific signals required for pancreatic regeneration in mice. Additional study of these processes and signals might lead to new approaches for treating type 1 diabetes or pancreatitis. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Desulfurization sorbent regeneration

DOEpatents

Jalan, V.M.; Frost, D.G.

1982-07-07

A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500/sup 0/C to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent. This method may be used for high-temperature fuel cells.

Evolution of the Chordate Regeneration Blastema: Differential Gene Expression and Conserved Role of Notch Signaling During Siphon Regeneration in the Ascidian Ciona

PubMed Central

Hamada, Mayuko; Goricki, Spela; Byerly, Mardi S.; Satoh, Noriyuki; Jeffery, William R.

2015-01-01

The regeneration of the oral siphon (OS) and other distal structures in the ascidian Ciona intestinalis occurs by epimorphosis involving the formation of a blastema of proliferating cells. Despite the longstanding use of Ciona as a model in molecular developmental biology, regeneration in this system has not been previously explored by molecular analysis. Here we have employed microarray analysis and quantitative real time RT-PCR to identify genes with differential expression profiles during OS regeneration. The majority of differentially expressed genes were downregulated during OS regeneration, suggesting roles in normal growth and homeostasis. However, a subset of differentially expressed genes was upregulated in the regenerating OS, suggesting functional roles during regeneration. Among the upregulated genes were key members of the Notch signaling pathway, including those encoding the delta and jagged ligands, two fringe modulators, and to a lesser extent the notch receptor. In situ hybridization showed a complementary pattern of delta1 and notch gene expression in the blastema of the regenerating OS. Chemical inhibition of the Notch signaling pathway reduced the levels of cell proliferation in the branchial sac, a stem cell niche that contributes progenitor cells to the regenerating OS, and in the OS regeneration blastema, where siphon muscle fibers eventually re-differentiate. Chemical inhibition also prevented the replacement of oral siphon pigment organs, sensory receptors rimming the entrance of the OS, and siphon muscle fibers, but had no effects on the formation of the wound epidermis. Since Notch signaling is involved in the maintenance of proliferative activity in both the Ciona and vertebrate regeneration blastema, the results suggest a conserved evolutionary role of this signaling pathway in chordate regeneration. The genes identified in this investigation provide the foundation for future molecular analysis of OS regeneration. PMID:26206613

Magnetic heat pumping

NASA Technical Reports Server (NTRS)

Brown, G. V. (Inventor)

1978-01-01

A ferromagnetic or ferrimagnetic element is used to control the temperature and applied magnetic field of the element to cause the state of the element as represented on a temperature-magnetic entropy diagram to repeatedly traverse a loop. The loop may have a first portion of concurrent substantially isothermal or constant temperature and increasing applied magnetic field, a second portion of lowering temperature and constant applied magnetic field, a third portion of isothermal and decreasing applied magnetic field, and a fourth portion of increasing temperature and constant applied magnetic field. Other loops may be four-sided, with two isotherms and two adiabats. Preferably, a regenerator is used to enhance desired cooling or heating effects, with varied magnetic fields, or varying temperatures including three-sided figures traversed by the representative point.

Skeletal muscle regeneration and impact of aging and nutrition.

PubMed

Domingues-Faria, Carla; Vasson, Marie-Paule; Goncalves-Mendes, Nicolas; Boirie, Yves; Walrand, Stephane

2016-03-01

After skeletal muscle injury a regeneration process takes place to repair muscle. Skeletal muscle recovery is a highly coordinated process involving cross-talk between immune and muscle cells. It is well known that the physiological activities of both immune cells and muscle stem cells decline with advancing age, thereby blunting the capacity of skeletal muscle to regenerate. The age-related reduction in muscle repair efficiency contributes to the development of sarcopenia, one of the most important factors of disability in elderly people. Preserving muscle regeneration capacity may slow the development of this syndrome. In this context, nutrition has drawn much attention: studies have demonstrated that nutrients such as amino acids, n-3 polyunsaturated fatty acids, polyphenols and vitamin D can improve skeletal muscle regeneration by targeting key functions of immune cells, muscle cells or both. Here we review the process of skeletal muscle regeneration with a special focus on the cross-talk between immune and muscle cells. We address the effect of aging on immune and skeletal muscle cells involved in muscle regeneration. Finally, the mechanisms of nutrient action on muscle regeneration are described, showing that quality of nutrition may help to preserve the capacity for skeletal muscle regeneration with age. Copyright © 2015 Elsevier B.V. All rights reserved.

High-throughput and multiplexed regeneration buffer scouting for affinity-based interactions.

PubMed

Geuijen, Karin P M; Schasfoort, Richard B; Wijffels, Rene H; Eppink, Michel H M

2014-06-01

Affinity-based analyses on biosensors depend partly on regeneration between measurements. Regeneration is performed with a buffer that efficiently breaks all interactions between ligand and analyte while maintaining the active binding site of the ligand. We demonstrated a regeneration buffer scouting using the combination of a continuous flow microspotter with a surface plasmon resonance imaging platform to simultaneously test 48 different regeneration buffers on a single biosensor. Optimal regeneration conditions are found within hours and consume little amounts of buffers, analyte, and ligand. This workflow can be applied to any ligand that is coupled through amine, thiol, or streptavidin immobilization. Copyright © 2014 Elsevier Inc. All rights reserved.

Magnetic flux transport of decaying active regions and enhanced magnetic network. [of solar supergranulation

NASA Technical Reports Server (NTRS)

Wang, Haimin; Zirin, Harold; Ai, Guoxiang

1991-01-01

Several series of coordinated observations on decaying active regions and enhanced magnetic network regions on the sun were carried out jointly at Big Bear Solar Observatory and at the Huairou Solar Observing Station of the Bejing Astronomical Observatory in China. The magnetic field evolution in several regions was followed closely for three to seven days. The magnetic flux transport from the remnants of decayed active regions was studied, along with the evolution and lifetime of the magnetic network which defines the boundaries of supergranules. The magnetic flux transport in an enhanced network region was studied in detail and found to be negative. Also briefly described are some properties of moving magnetic features around a sunspot. Results of all of the above studies are presented.

Characterization of the Regulation and Function of Zinc-Dependent Histone Deacetylases During Mouse Liver Regeneration

PubMed Central

Huang, Jiansheng; Barr, Emily; Rudnick, David A.

2013-01-01

The studies reported here were undertaken to define the regulation and functional importance of zinc-dependent histone deacetylase (Zn-HDAC) activity during liver regeneration using the mouse partial hepatectomy (PH) model. The results showed that hepatic HDAC activity was significantly increased in nuclear and cytoplasmic fractions following PH. Further analyses showed isoform-specific effects of PH on HDAC mRNA and protein expression, with increased expression of the class I HDACs, 1 and 8, and class II HDAC4 in regenerating liver. Hepatic expression of (class II) HDAC5 was unchanged after PH; however HDAC5 exhibited transient nuclear accumulation in regenerating liver. These changes in hepatic HDAC expression, subcellular localization, and activity coincided with diminished histone acetylation in regenerating liver. The significance of these events was investigated by determining the effects of suberoylanilide hydroxyamic acid (SAHA, a specific inhibitor of Zn-HDAC activity) on hepatic regeneration. The results showed that SAHA-treatment suppressed the effects of PH on histone deacetylation and hepatocellular BrdU incorporation. Further examination showed that SAHA blunted hepatic expression and activation of cell cycle signals downstream of induction of cyclin D1 expression in mice subjected to PH. Conclusion The data reported here demonstrate isoform-specific regulation of Zn-HDAC expression, subcellular localization, and activity in regenerating liver. These studies also indicate that HDAC activity promotes liver regeneration by regulating hepatocellular cell cycle progression at a step downstream of cyclin D1 induction. PMID:23258575

Calpain activity in fast, slow, transforming, and regenerating skeletal muscles of rat.

PubMed

Sultan, K R; Dittrich, B T; Pette, D

2000-09-01

Fiber-type transitions in adult skeletal muscle induced by chronic low-frequency stimulation (CLFS) encompass coordinated exchanges of myofibrillar protein isoforms. CLFS-induced elevations in cytosolic Ca(2+) could activate proteases, especially calpains, the major Ca(2+)-regulated cytosolic proteases. Calpain activity determined by a fluorogenic substrate in the presence of unaltered endogenous calpastatin activities increased twofold in low-frequency-stimulated extensor digitorum longus (EDL) muscle, reaching a level intermediate between normal fast- and slow-twitch muscles. micro- and m-calpains were delineated by a calpain-specific zymographical assay that assessed total activities independent of calpastatin and distinguished between native and processed calpains. Contrary to normal EDL, structure-bound, namely myofibrillar and microsomal calpains, were abundant in soleus muscle. However, the fast-to-slow conversion of EDL was accompanied by an early translocation of cytosolic micro-calpain, suggesting that myofibrillar and microsomal micro-calpain was responsible for the twofold increase in activity and thus involved in controlled proteolysis during fiber transformation. This is in contrast to muscle regeneration where m-calpain translocation predominated. Taken together, we suggest that translocation is an important step in the control of calpain activity in skeletal muscle in vivo.

Perspectives on human regeneration.

PubMed

Stark, James F

2018-06-12

Regeneration is a concept that has fascinated humans for centuries. Whether we have been trying to bring things back to life, extract additional resources from the world, or remodel our living spaces-domestic and urban-it is often presented as an unproblematic force for good. But what exactly does it mean to regenerate a body, mind or space? This paper, which introduces a collection of contributions on the theme of human regeneration, explores the limits and possibilities of regeneration as a conceptual tool for understanding the biological realm. What does it mean to be regenerated? How can a scholarly focus on this concept enrich our histories of bodies, ageing, disability and science, technology and medicine? As a secondary goal, I identify two distinct aspects of regeneration-'hard' and 'soft' regeneration-which concern the medical and social elements of regeneration respectively. By recognising that everything from cosmetics and fictions to prosthetics and organs grown in vitro display a combination of 'hard' and 'soft' elements, we are better placed to understand that the biological and social must be considered in consort for us to fully appreciate the meanings and practices that underpin multiple forms of human regeneration.

Magnetic field effect for cellulose nanofiber alignment

NASA Astrophysics Data System (ADS)

Kim, Jaehwan; Chen, Yi; Kang, Kwang-Sun; Park, Young-Bin; Schwartz, Mark

2008-11-01

Regenerated cellulose formed into cellulose nanofibers under strong magnetic field and aligned perpendicularly to the magnetic field. Well-aligned microfibrils were found as the exposure time of the magnetic field increased. Better alignment and more crystalline structure of the cellulose resulted in the increased decomposition temperature of the material. X-ray crystallograms showed that crystallinity index of the cellulose increased as the exposure time of the magnetic field increased.

Regeneration of granular activated carbon saturated with acetone and isopropyl alcohol via a recirculation process under H2O2/UV oxidation.

PubMed

Horng, Richard S; Tseng, I-Chin

2008-06-15

This study examines a water-based system, coupling an adsorber and a photoreactor, for regeneration of granular activated carbon (GAC) saturated with acetone and isopropyl alcohol (IPA). Through water recirculation the regeneration reaction was operated in both intermittent and continuous ultraviolet illumination modes. With a periodic dosage of hydrogen peroxide not only was regeneration efficient but it was also catalyzed by GAC in the adsorber. The concentrations of acetone, solution chemical oxygen demand (COD), pH and organic residues on GAC surfaces were measured during regenerations. Both pH and solution COD were found to correlate with regeneration completion as measured by organic residue on GAC surfaces in four regeneration cycles with acetone. Solution pH decreased to the acidic values and then returned to near its original value when organic residues were 0.085-0.255 mg/g GAC, that is, destruction efficiency of adsorbed acetone on the GAC surface was more than 99%. Likewise, solution COD became low (<100 mg/l) at regeneration completion. The pH variation pattern was then applied to another four cycles of regeneration with IPA, and successfully reflected the timing of complete regeneration. The final levels of organic residue on GAC surfaces were between 0.135 and 0.310 mg/g GAC in each of four regeneration cycles, each of which had been stopped based on the measurements of pH and solution COD. Furthermore, nearly the same batch of GAC could be repeatedly used with little changes in physicochemical properties in each of eight cycles: adsorptive capacities were 95+/-7 mg acetone/g GAC and 87+/-3 mg IPA/g GAC, and breakthrough time was 0.86+/-0.05 for acetone and 0.78+/-0.03 h for IPA. An economic assessment of the system showed that the operating cost was about 0.04 USD for treating every gram of acetone in the air.

An active role for magnetic fields in solar flares

NASA Technical Reports Server (NTRS)

Rust, D. M.

1976-01-01

Observations of photospheric magnetic fields are reviewed to determine whether changes in such fields can be related to flare activity, assuming that magnetic fields play an active role in providing flare energy. An intimate relation between emerging fields and bright flare knots is noted, and it is shown that the activation and eruption of an H-alpha filament is indicative of a major disruption of a magnetic field just prior to a flare. Observations of twisting motions in a filament just before a flare are discussed, erupting untwisting filaments are taken as unambiguous evidence for restructuring of the magnetic fields associated with flares, and it is argued that magnetic-field changes in the midst of most flares are obvious. It is concluded that successive brightenings in a family of loops may be evidence for the spread of a magnetic-field reconnection point from one field concentration to another and that flares may well take place in regions of field-line reconnection. This latter conclusion is illustrated using an empirical flare model that involves field-line reconnection, filament activation, and emerging magnetic flux.

Method for regeneration and activity improvement of syngas conversion catalyst

DOEpatents

Lucki, Stanley J.; Brennan, James A.

1980-01-01

A method is disclosed for the treatment of single particle iron-containing syngas (synthes.s gas) conversion catalysts comprising iron, a crystalline acidic aluminosilicate zeolite having a silica to alumina ratio of at least 12, a pore size greater than about 5 Angstrom units and a constraint index of about 1-12 and a matrix. The catalyst does not contain promoters and the treatment is applicable to either the regeneration of said spent single particle iron-containing catalyst or for the initial activation of fresh catalyst. The treatment involves air oxidation, hydrogen reduction, followed by a second air oxidation and contact of the iron-containing single particle catalyst with syngas prior to its use for the catalytic conversion of said syngas. The single particle iron-containing catalysts are prepared from a water insoluble organic iron compound.

Lgr5+ Cells Regenerate Hair Cells via Proliferation and Direct Transdifferentiation in Damaged Neonatal Mouse Utricle

PubMed Central

Wang, Tian; Chai, Renjie; Kim, Grace S.; Pham, Nicole; Jansson, Lina; Nguyen, Duc-Huy; Kuo, Bryan; May, Lindsey; Zuo, Jian; Cunningham, Lisa L.; Cheng, Alan G.

2015-01-01

Recruitment of endogenous progenitors is critical during tissue repair. The inner ear utricle requires mechanosensory hair cells (HCs) to detect linear acceleration. After damage, non-mammalian utricles regenerate HCs via both proliferation and direct transdifferentiation. In adult mammals, limited transdifferentiation from unidentified progenitors occurs to regenerate extrastriolar Type II HCs. Here, we show that HC damage in neonatal mouse utricle activates the Wnt target gene Lgr5 in striolar supporting cells. Lineage tracing and time-lapse microscopy reveal that Lgr5+ cells transdifferentiate into HC-like cells in vitro. In contrast to adults, HC ablation in neonatal utricles in vivo recruits Lgr5+ cells to regenerate striolar HCs through mitotic and transdifferentiation pathways. Both Type I and II HCs are regenerated, and regenerated HCs display stereocilia and synapses. Lastly, stabilized β-catenin in Lgr5+ cells enhances mitotic activity and HC regeneration. Thus Lgr5 marks Wnt-regulated, damage-activated HC progenitors and may help uncover factors driving mammalian HC regeneration. PMID:25849379

Regenerable Iodine Water-Disinfection System

NASA Technical Reports Server (NTRS)

Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

1994-01-01

Iodinated resin bed for disinfecting water regenerated to extend its useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle was manually controlled in demonstration, readily automated to start and stop according to signals and stop according to signals from concentration sensors. Further benefit of regeneration is that regeneration bed provides highly concentrated biocide source (200 mg/L) when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

Drosophila Sulf1 is required for the termination of intestinal stem cell division during regeneration.

PubMed

Takemura, Masahiko; Nakato, Hiroshi

2017-01-15

Stem cell division is activated to trigger regeneration in response to tissue damage. The molecular mechanisms by which this stem cell mitotic activity is properly repressed at the end of regeneration are poorly understood. Here, we show that a specific modification of heparan sulfate is crucial for regulating Drosophila intestinal stem cell (ISC) division during normal midgut homeostasis and regeneration. Loss of the extracellular heparan sulfate endosulfatase Sulf1 resulted in increased ISC division during normal homeostasis, which was caused by upregulation of mitogenic signaling including the JAK-STAT, EGFR and Hedgehog pathways. Using a regeneration model, we found that ISCs failed to properly halt division at the termination stage in Sulf1 mutants, showing that Sulf1 is required for terminating ISC division at the end of regeneration. We propose that post-transcriptional regulation of mitogen signaling by heparan sulfate structural modifications provides a new regulatory step for precise temporal control of stem cell activity during regeneration. © 2017. Published by The Company of Biologists Ltd.

Drosophila Sulf1 is required for the termination of intestinal stem cell division during regeneration

PubMed Central

2017-01-01

ABSTRACT Stem cell division is activated to trigger regeneration in response to tissue damage. The molecular mechanisms by which this stem cell mitotic activity is properly repressed at the end of regeneration are poorly understood. Here, we show that a specific modification of heparan sulfate is crucial for regulating Drosophila intestinal stem cell (ISC) division during normal midgut homeostasis and regeneration. Loss of the extracellular heparan sulfate endosulfatase Sulf1 resulted in increased ISC division during normal homeostasis, which was caused by upregulation of mitogenic signaling including the JAK-STAT, EGFR and Hedgehog pathways. Using a regeneration model, we found that ISCs failed to properly halt division at the termination stage in Sulf1 mutants, showing that Sulf1 is required for terminating ISC division at the end of regeneration. We propose that post-transcriptional regulation of mitogen signaling by heparan sulfate structural modifications provides a new regulatory step for precise temporal control of stem cell activity during regeneration. PMID:27888216

Scaling and Optimization of Magnetic Refrigeration for Commercial Building HVAC Systems Greater than 175 kW in Capacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; West, David L; Mallow, Anne M

Heating, ventilation, air-conditioning and refrigeration (HVACR) account for approximately one- third of building energy consumption. Magnetic refrigeration presents an opportunity for significant energy savings and emissions reduction for serving the building heating, cooling, and refrigeration loads. In this paper, we have examined the magnet and MCE material requirements for scaling magnetic refrigeration systems for commercial building cooling applications. Scaling relationships governing the resources required for magnetic refrigeration systems have been developed. As system refrigeration capacity increases, the use of superconducting magnet systems becomes more applicable, and a comparison is presented of system requirements for permanent and superconducting (SC) magnetization systems.more » Included in this analysis is an investigation of the ability of superconducting magnet based systems to overcome the parasitic power penalty of the cryocooler used to keep SC windings at cryogenic temperatures. Scaling relationships were used to develop the initial specification for a SC magnet-based active magnetic regeneration (AMR) system. An optimized superconducting magnet was designed to support this system. In this analysis, we show that the SC magnet system consisting of two 0.38 m3 regenerators is capable of producing 285 kW of cooling power with a T of 28 K. A system COP of 4.02 including cryocooler and fan losses which illustrates that an SC magnet-based system can operate with efficiency comparable to traditional systems and deliver large cooling powers of 285.4 kW (81.2 Tons).« less

Characterization of the regulation and function of zinc-dependent histone deacetylases during rodent liver regeneration.

PubMed

Huang, Jiansheng; Barr, Emily; Rudnick, David A

2013-05-01

The studies reported here were undertaken to define the regulation and functional importance of zinc-dependent histone deacetylase (Zn-HDAC) activity during liver regeneration using the mouse partial hepatectomy (PH) model. The results showed that hepatic HDAC activity was significantly increased in nuclear and cytoplasmic fractions following PH. Further analyses showed isoform-specific effects of PH on HDAC messenger RNA (mRNA) and protein expression, with increased expression of the class I HDACs, 1 and 8, and class II HDAC4 in regenerating liver. Hepatic expression of (class II) HDAC5 was unchanged after PH; however, HDAC5 exhibited transient nuclear accumulation in regenerating liver. These changes in hepatic HDAC expression, subcellular localization, and activity coincided with diminished histone acetylation in regenerating liver. The significance of these events was investigated by determining the effects of suberoylanilide hydroxyamic acid (SAHA, a specific inhibitor of Zn-HDAC activity) on hepatic regeneration. The results showed that SAHA treatment suppressed the effects of PH on histone deacetylation and hepatocellular bromodeoxyuridine (BrdU) incorporation. Further examination showed that SAHA blunted hepatic expression and activation of cell cycle signals downstream of induction of cyclin D1 expression in mice subjected to PH. The data reported here demonstrate isoform-specific regulation of Zn-HDAC expression, subcellular localization, and activity in regenerating liver. These studies also indicate that HDAC activity promotes liver regeneration by regulating hepatocellular cell cycle progression at a step downstream of cyclin D1 induction. Copyright © 2012 American Association for the Study of Liver Diseases.

Rac1-PAK2 pathway is essential for zebrafish heart regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Xiangwen; He, Quanze; Li, Guobao

P-21 activated kinases, or PAKs, are serine–threonine kinases that play important roles in diverse heart functions include heart development, cardiovascular development and function in a range of models; however, the mechanisms by which PAKs mediate heart regeneration are unknown. Here, we demonstrate that PAK2 and PAK4 expression is induced in cardiomyocytes and vessels, respectively, following zebrafish heart injury. Inhibition of PAK2 and PAK4 using a specific small molecule inhibitor impedes cardiomyocyte proliferation/dedifferentiation and cardiovascular regeneration, respectively. Cdc42 is specifically expressed in the ventricle and may function upstream of PAK2 but not PAK4 under normal conditions and that cardiomyocyte proliferentation duringmore » heart regeneration relies on Rac1-mediated activation of Pak2. Our results indicate that PAKs play a key role in heart regeneration.« less

TNF signaling and macrophages govern fin regeneration in zebrafish larvae.

PubMed

Nguyen-Chi, Mai; Laplace-Builhé, Béryl; Travnickova, Jana; Luz-Crawford, Patricia; Tejedor, Gautier; Lutfalla, Georges; Kissa, Karima; Jorgensen, Christian; Djouad, Farida

2017-08-10

Macrophages are essential for appendage regeneration after amputation in regenerative species. The molecular mechanisms through which macrophages orchestrate blastema formation and regeneration are still unclear. Here, we use the genetically tractable and transparent zebrafish larvae to study the functions of polarized macrophage subsets during caudal fin regeneration. After caudal fin amputation, we show an early and transient accumulation of pro-inflammatory macrophages concomitant with the accumulation of non-inflammatory macrophages which, in contrast to pro-inflammatory macrophages, remain associated to the fin until the end of the regeneration. Chemical and genetic depletion of macrophages suggested that early recruited macrophages that express TNFα are critical for blastema formation. Combining parabiosis and morpholino knockdown strategies, we show that TNFα/TNFR1 signaling pathway is required for the fin regeneration. Our study reveals that TNFR1 has a necessary and direct role in blastema cell activation suggesting that macrophage subset balance provides the accurate TNFα signal to prime regeneration in zebrafish.

The HMI Magnetic Activity Index for Local-Area Helioseismology

NASA Astrophysics Data System (ADS)

Bogart, Richard S.; Baldner, Charles

2017-08-01

In order to provide context for the mapping of sub-surface flows and thermal structure by local helioseismic techniques and the study of their relation to local magnetic activity, a local Magnetic Activity Index (MAI) was introduced. The MAI provides an appropriate index value corresponding precisely to the extent in space and time of each region analyzed. It is intended to be a measure of the total magnetic flux in the region. Hemispheric averages of the MAI are very well correlated with independent global measures of solar magnetic activity. Improvements in the determination of the MAI from Helioseismic and Magnetic Imager (HMI) measurements have revealed statistical anomalies affecting a small but significant number of high-cadence (45-sec) magnetograms. We describe modifications to the MAI being explored, the identification and treatment of anomalous magnetic field values, and explore likely causes.

Activation of Pax7-Positive Cells in a Non-Contractile Tissue Contributes to Regeneration of Myogenic Tissues in the Electric Fish S. macrurus

PubMed Central

Weber, Christopher M.; Martindale, Mark Q.; Tapscott, Stephen J.; Unguez, Graciela A.

2012-01-01

The ability to regenerate tissues is shared across many metazoan taxa, yet the type and extent to which multiple cellular mechanisms come into play can differ across species. For example, urodele amphibians can completely regenerate all lost tissues, including skeletal muscles after limb amputation. This remarkable ability of urodeles to restore entire limbs has been largely linked to a dedifferentiation-dependent mechanism of regeneration. However, whether cell dedifferentiation is the fundamental factor that triggers a robust regeneration capacity, and whether the loss or inhibition of this process explains the limited regeneration potential in other vertebrates is not known. Here, we studied the cellular mechanisms underlying the repetitive regeneration of myogenic tissues in the electric fish S. macrurus. Our in vivo microinjection studies of high molecular weight cell lineage tracers into single identified adult myogenic cells (muscle or noncontractile muscle-derived electrocytes) revealed no fragmentation or cellularization proximal to the amputation plane. In contrast, ultrastructural and immunolabeling studies verified the presence of myogenic stem cells that express the satellite cell marker Pax7 in mature muscle fibers and electrocytes of S. macrurus. These data provide the first example of Pax-7 positive muscle stem cells localized within a non-contractile electrogenic tissue. Moreover, upon amputation, Pax-7 positive cells underwent a robust replication and were detected exclusively in regions that give rise to myogenic cells and dorsal spinal cord components revealing a regeneration process in S. macrurus that is dependent on the activation of myogenic stem cells for the renewal of both skeletal muscle and the muscle-derived electric organ. These data are consistent with the emergent concept in vertebrate regeneration that different tissues provide a distinct progenitor cell population to the regeneration blastema, and these progenitor cells

Nerve-muscle activation by rotating permanent magnet configurations.

PubMed

Watterson, Peter A; Nicholson, Graham M

2016-04-01

The standard method of magnetic nerve activation using pulses of high current in coils has drawbacks of high cost, high electrical power (of order 1 kW), and limited repetition rate without liquid cooling. Here we report a new technique for nerve activation using high speed rotation of permanent magnet configurations, generating a sustained sinusoidal electric field using very low power (of order 10 W). A high ratio of the electric field gradient divided by frequency is shown to be the key indicator for nerve activation at high frequencies. Activation of the cane toad sciatic nerve and attached gastrocnemius muscle was observed at frequencies as low as 180 Hz for activation of the muscle directly and 230 Hz for curved nerves, but probably not in straight sections of nerve. These results, employing the first prototype device, suggest the opportunity for a new class of small low-cost magnetic nerve and/or muscle stimulators. Conventional pulsed current systems for magnetic neurostimulation are large and expensive and have limited repetition rate because of overheating. Here we report a new technique for nerve activation, namely high-speed rotation of a configuration of permanent magnets. Analytical solutions of the cable equation are derived for the oscillating electric field generated, which has amplitude proportional to the rotation speed. The prototype device built comprised a configuration of two cylindrical magnets with antiparallel magnetisations, made to rotate by interaction between the magnets' own magnetic field and three-phase currents in coils mounted on one side of the device. The electric field in a rectangular bath placed on top of the device was both numerically evaluated and measured. The ratio of the electric field gradient on frequency was approximately 1 V m(-2) Hz(-1) near the device. An exploratory series of physiological tests was conducted on the sciatic nerve and attached gastrocnemius muscle of the cane toad (Bufo marinus). Activation was

Tissue regeneration with photobiomodulation

NASA Astrophysics Data System (ADS)

Tang, Elieza G.; Arany, Praveen R.

2013-03-01

Low level light therapy (LLLT) has been widely reported to reduce pain and inflammation and enhance wound healing and tissue regeneration in various settings. LLLT has been noted to have both stimulatory and inhibitory biological effects and these effects have been termed Photobiomodulation (PBM). Several elegant studies have shown the key role of Cytochrome C oxidase and ROS in initiating this process. The downstream biological responses remain to be clearly elucidated. Our work has demonstrated activation of an endogenous latent growth factor complex, TGF-β1, as one of the major biological events in PBM. TGF-β1 has critical roles in various biological processes especially in inflammation, immune responses, wound healing and stem cell biology. This paper overviews some of the studies demonstrating the efficacy of PBM in promoting tissue regeneration.

Regenerable Iodine Water-Disinfection System

NASA Technical Reports Server (NTRS)

Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

1994-01-01

Iodinated resin bed for disinfecting water regenerated to extend useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle manually controlled readily automated to start and stop according to signals from concentration sensors. Further benefit of regeneration is bed provides highly concentrated biocide source when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

Regeneration and health: a structured, rapid literature review.

PubMed

McCartney, G; Hearty, W; Taulbut, M; Mitchell, R; Dryden, R; Collins, C

2017-07-01

To identify and synthesise what is known about the impacts of regeneration on health, health inequalities and their socio-economic determinants. Rapid, structured literature review. A rapid, structured approach was undertaken to identifying relevant studies involving a search of peer-reviewed literature databases, an Internet search to identify relevant grey literature, and a review of articles citing two key systematic reviews. The identified citations were screened, critically appraised according to the research design and narratively synthesised. Of the 1382 identified citations, 46 were screened as relevant to the review and included in the synthesis. Fifteen citations were reviews but most of the evidence identified or included within the reviews was of medium or low quality due to a lack of longitudinal follow-up, low response rates or attrition. The evidence base on the impacts of regeneration is generally not of high quality and is prone to bias. However, it is theorised as being an important means of addressing the socio-economic determinants of health. Housing refurbishment (generally, and for specific improvements) seems likely to lead to small improvements in health, whereas rehousing and mixed-tenure approaches have less clear impacts on health and carry risks of disruption to social networks and higher rents. Changes in the social composition of communities (gentrification) is a common outcome of regeneration and some 'partnership' approaches to regeneration have been shown to have caused difficulties within communities. The evidence base for regeneration activities is limited but they have substantial potential to contribute to improving population health. Better quality evidence is available for there being positive health impacts from housing-led regeneration programmes involving refurbishment and specific housing improvements. There is also some evidence of the potential harms of regeneration activities, including social stratification

Activation of the unfolded protein response promotes axonal regeneration after peripheral nerve injury.

PubMed

Oñate, Maritza; Catenaccio, Alejandra; Martínez, Gabriela; Armentano, Donna; Parsons, Geoffrey; Kerr, Bredford; Hetz, Claudio; Court, Felipe A

2016-02-24

Although protein-folding stress at the endoplasmic reticulum (ER) is emerging as a driver of neuronal dysfunction in models of spinal cord injury and neurodegeneration, the contribution of this pathway to peripheral nerve damage remains poorly explored. Here we targeted the unfolded protein response (UPR), an adaptive reaction against ER stress, in mouse models of sciatic nerve injury and found that ablation of the transcription factor XBP1, but not ATF4, significantly delay locomotor recovery. XBP1 deficiency led to decreased macrophage recruitment, a reduction in myelin removal and axonal regeneration. Conversely, overexpression of XBP1s in the nervous system in transgenic mice enhanced locomotor recovery after sciatic nerve crush, associated to an improvement in key pro-regenerative events. To assess the therapeutic potential of UPR manipulation to axonal regeneration, we locally delivered XBP1s or an shRNA targeting this transcription factor to sensory neurons of the dorsal root ganglia using a gene therapy approach and found an enhancement or reduction of axonal regeneration in vivo, respectively. Our results demonstrate a functional role of specific components of the ER proteostasis network in the cellular changes associated to regeneration and functional recovery after peripheral nerve injury.

ERα promotes murine hematopoietic regeneration through the Ire1α-mediated unfolded protein response

PubMed Central

Chapple, Richard H; Hu, Tianyuan; Tseng, Yu-Jung; Liu, Lu; Kitano, Ayumi; Luu, Victor; Hoegenauer, Kevin A; Iwawaki, Takao; Li, Qing

2018-01-01

Activation of the unfolded protein response (UPR) sustains protein homeostasis (proteostasis) and plays a fundamental role in tissue maintenance and longevity of organisms. Long-range control of UPR activation has been demonstrated in invertebrates, but such mechanisms in mammals remain elusive. Here, we show that the female sex hormone estrogen regulates the UPR in hematopoietic stem cells (HSCs). Estrogen treatment increases the capacity of HSCs to regenerate the hematopoietic system upon transplantation and accelerates regeneration after irradiation. We found that estrogen signals through estrogen receptor α (ERα) expressed in hematopoietic cells to activate the protective Ire1α-Xbp1 branch of the UPR. Further, ERα-mediated activation of the Ire1α-Xbp1 pathway confers HSCs with resistance against proteotoxic stress and promotes regeneration. Our findings reveal a systemic mechanism through which HSC function is augmented for hematopoietic regeneration. PMID:29451493

Effects of Aging on Thyroarytenoid Muscle Regeneration

PubMed Central

Lee, Kyungah; Kletzien, Heidi; Connor, Nadine P.; Schultz, Edward; Chamberlain, Connie S.; Bless, Diane M.

2012-01-01

Objectives/hypotheses Regenerative properties of age-associated changes in the intrinsic laryngeal muscles following injury are unclear. The purpose of this study was to investigate the regenerative properties of the thyroarytenoid muscle (TA) in an aging rat model. The hypothesis was that, following myotoxic injury, old animals would exhibit a decrease in mitotic activities of muscle satellite cells when compared with younger rats, suggesting reduced regenerative potential in the aging rat TA. Study Design Animal group comparison. Method Regeneration responses following injury to the TA were examined in 18 young adult, middle-aged, and old Fischer 344/Brown Norway rats. TA muscle fiber cross sectional area (CSA), satellite cell mitosis (number/fiber), and regeneration index (CSA injured side/CSA non-injured side) were measured and compared across age groups. Results Young animals had a significantly higher regeneration index than the middle-aged and old groups. Within the lateral region of the TA (LTA), the regeneration index was significantly higher in the young animals than in the middle-aged and old animals. The regeneration index of the medial TA (MTA) was significantly higher than the LTA across all age groups. Conclusions The regenerative capacity of the TA muscle is impaired with increasing age. Evidence N/A PMID:22965923

Automated Assistance for Designing Active Magnetic Bearings

NASA Technical Reports Server (NTRS)

Imlach, Joseph

2008-01-01

MagBear12 is a computer code that assists in the design of radial, heteropolar active magnetic bearings (AMBs). MagBear12 was developed to help in designing the system described in "Advanced Active-Magnetic-Bearing Thrust-Measurement System". Beyond this initial application, MagBear12 is expected to be useful for designing AMBs for a variety of rotating machinery. This program incorporates design rules and governing equations that are also implemented in other, proprietary design software used by AMB manufacturers. In addition, this program incorporates an advanced unpublished fringing-magnetic-field model that increases accuracy beyond that offered by the other AMB-design software.

Active magnetic bearings applied to industrial compressors

NASA Technical Reports Server (NTRS)

Kirk, R. G.; Hustak, J. F.; Schoeneck, K. A.

1993-01-01

The design and shop test results are given for a high-speed eight-stage centrifugal compressor supported by active magnetic bearings. A brief summary of the basic operation of active magnetic bearings and the required rotor dynamics analysis are presented with specific attention given to design considerations for optimum rotor stability. The concerns for retrofits of magnetic bearings in existing machinery are discussed with supporting analysis of a four-stage centrifugal compressor. The current status of industrial machinery in North America using this new support system is presented and recommendations are given on design and analysis requirements for successful machinery operation of either retrofit or new design turbomachinery.

Complement anaphylatoxin C3a is a potent inducer of embryonic chick retina regeneration

PubMed Central

Haynes, Tracy; Luz-Madrigal, Agustin; Reis, Edimara S.; Echeverri Ruiz, Nancy P.; Grajales-Esquivel, Erika; Tzekou, Apostolia; Tsonis, Panagiotis A.; Lambris, John D.; Del Rio-Tsonis, Katia

2013-01-01

Identifying the initiation signals for tissue regeneration in vertebrates is one of the major challenges in regenerative biology. Much of the research thus far has indicated that certain growth factors have key roles. Here we show that complement fragment C3a is sufficient to induce complete regeneration of the embryonic chick retina from stem/progenitor cells present in the eye, independent of fibroblast growth factor receptor signaling. Instead, C3a induces retina regeneration via STAT3 activation, which in turn activates the injury- and inflammation-responsive factors, IL-6, IL-8 and TNF-α. This activation sets forth regulation of Wnt2b, Six3 and Sox2, genes associated with retina stem and progenitor cells. Thus, our results establish a mechanism for retina regeneration based on injury and inflammation signals. Furthermore, our results indicate a unique function for complement anaphylatoxins that implicate these molecules in the induction and complete regeneration of the retina, opening new avenues of experimentation in the field. PMID:23942241

In vivo assessment of peripheral nerve regeneration by diffusion tensor imaging.

PubMed

Morisaki, Shinsuke; Kawai, Yuko; Umeda, Masahiro; Nishi, Mayumi; Oda, Ryo; Fujiwara, Hiroyoshi; Yamada, Kei; Higuchi, Toshihiro; Tanaka, Chuzo; Kawata, Mitsuhiro; Kubo, Toshikazu

2011-03-01

To evaluate the sensitivity of diffusion tensor imaging (DTI) in assessing peripheral nerve regeneration in vivo. We assessed the changes in the DTI parameters and histological analyses after nerve injury to examine degeneration and regeneration in the rat sciatic nerves. For magnetic resonance imaging (MRI), 16 rats were randomly divided into two groups: group P (permanently crushed; n = 7) and group T (temporally crushed; n = 9). Serial MRI of the right leg was performed before the operation, and then performed at the timepoints of 1, 2, 3, and 4 weeks after the crush injury. The changes in fractional anisotropy (FA), axial diffusivity (λ(∥)), and radial diffusivity (λ(⟂)) were quantified. For histological analyses, the number of axons and the myelinated axon areas were quantified. Decreased FA and increased λ(⟂) were observed in the degenerative phase, and increased FA and decreased λ(⟂) were observed in the regenerative phase. The changes in FA and λ(⟂) were strongly correlated with histological changes, including axonal and myelin regeneration. DTI parameters, especially λ(⟂) , can be good indicators for peripheral nerve regeneration and can be applied as noninvasive diagnostic tools for a variety of neurological diseases. Copyright © 2011 Wiley-Liss, Inc.

Impaired lipid accumulation in the liver of Tsc2-heterozygous mice during liver regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obayashi, Yoko, E-mail: youko_oobayashi@ajinomoto.com; Campbell, Jean S.; Fausto, Nelson

Highlights: •Tuberin phosphorylation correlated with mTOR activation in early liver regeneration. •Liver regeneration in the Tsc2+/− mice was not enhanced. •The Tsc2+/− livers failed to accumulate lipid bodies during liver regeneration. •Mortality rate increased in Tsc2+/− mice after partial hepatectomy. •Tuberin plays a critical role in hepatic lipid accumulation to support regeneration. -- Abstract: Tuberin is a negative regulator of mTOR pathway. To investigate the function of tuberin during liver regeneration, we performed 70% hepatectomy on wild-type and Tsc2+/− mice. We found the tuberin phosphorylation correlated with mTOR activation during early liver regeneration in wild-type mice. However, liver regeneration inmore » the Tsc2+/− mice was not enhanced. Instead, the Tsc2+/− livers failed to accumulate lipid bodies, and this was accompanied by increased mortality. These findings suggest that tuberin plays a critical role in liver energy balance by regulating hepatocellular lipid accumulation during early liver regeneration. These effects may influence the role of mTORC1 on cell growth and proliferation.« less

The Hippo pathway in tissue homeostasis and regeneration.

PubMed

Wang, Yu; Yu, Aijuan; Yu, Fa-Xing

2017-05-01

While several organs in mammals retain partial regenerative capability following tissue damage, the underlying mechanisms remain unclear. Recently, the Hippo signaling pathway, better known for its function in organ size control, has been shown to play a pivotal role in regulating tissue homeostasis and regeneration. Upon tissue injury, the activity of YAP, the major effector of the Hippo pathway, is transiently induced, which in turn promotes expansion of tissue-resident progenitors and facilitates tissue regeneration. In this review, with a general focus on the Hippo pathway, we will discuss its major components, functions in stem cell biology, involvement in tissue regeneration in different organs, and potential strategies for developing Hippo pathway-targeted regenerative medicines.

Magnetic helicity in emerging solar active regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y.; Hoeksema, J. T.; Bobra, M.

Using vector magnetic field data from the Helioseismic and Magnetic Imager instrument aboard the Solar Dynamics Observatory, we study magnetic helicity injection into the corona in emerging active regions (ARs) and examine the hemispheric helicity rule. In every region studied, photospheric shearing motion contributes most of the helicity accumulated in the corona. In a sample of 28 emerging ARs, 17 follow the hemisphere rule (61% ± 18% at a 95% confidence interval). Magnetic helicity and twist in 25 ARs (89% ± 11%) have the same sign. The maximum magnetic twist, which depends on the size of an AR, is inferredmore » in a sample of 23 emerging ARs with a bipolar magnetic field configuration.« less

Cross-talk between KLF4 and STAT3 regulates axon regeneration

NASA Astrophysics Data System (ADS)

Qin, Song; Zou, Yuhua; Zhang, Chun-Li

2013-10-01

Cytokine-induced activation of signal transducer and activator of transcription 3 (STAT3) promotes the regrowth of damaged axons in the adult central nervous system (CNS). Here we show that KLF4 physically interacts with STAT3 upon cytokine-induced phosphorylation of tyrosine 705 (Y705) on STAT3. This interaction suppresses STAT3-dependent gene expression by blocking its DNA-binding activity. The deletion of KLF4 in vivo induces axon regeneration of adult retinal ganglion cells (RGCs) via Janus kinase (JAK)-STAT3 signalling. This regeneration can be greatly enhanced by exogenous cytokine treatment, or removal of an endogenous JAK-STAT3 pathway inhibitor called suppressor of cytokine signalling 3 (SOCS3). These findings reveal an unexpected cross-talk between KLF4 and activated STAT3 in the regulation of axon regeneration that might have therapeutic implications in promoting repair of injured adult CNS.

Ceramic regenerator program

NASA Technical Reports Server (NTRS)

Franklin, Jerrold E.

1991-01-01

The feasibility of fabricating an Air Turbo Ramjet (ATR) regenerator containing intricate hydraulic passages from a ceramic material in order to allow operation with high temperature combustion gas and to reduce weight as compared with metallic materials was demonstrated. Platelet technology, ceramic tape casting, and multilayer ceramic packaging techniques were used in this fabrication of subscale silicon nitride components. Proof-of-concept demonstrations were performed to simulate a methane cooled regenerator for an ATR engine. The regenerator vane was designed to operate at realistic service conditions, i.e., 600 psi in a 3500 R (3040 F), 500 fps combustion gas environment. A total of six regenerators were fabricated and tested. The regenerators were shown to be able to withstand internal pressurization to 1575 psi. They were subjected to testing in 500 fps, 3560 R (3100 F) air/propane combustion products and were operated satisfactorily for an excess of 100 hr and 40 thermal cycles which exceeded 2460 R (2000 F).

Regeneration methods

Treesearch

James P. Barnett; James B. Baker

1991-01-01

Southern pines can be regenerated naturally, by clearcutting, seedtree, shelterwood, or selection reproduction culling methods, or artificially, by direct seeding or by planting either container or bareroot seedlings. All regeneration methods have inherent advantages: and disadvantages; thus, land managers must consider many factors before deciding on a specific method...

Behaviour of telomere and telomerase during aging and regeneration in zebrafish.

PubMed

Anchelin, Monique; Murcia, Laura; Alcaraz-Pérez, Francisca; García-Navarro, Esther M; Cayuela, María L

2011-02-09

Telomere length and telomerase activity are important factors in the pathobiology of human diseases. Age-related diseases and premature aging syndromes are characterized by short telomeres, which can compromise cell viability, whereas tumour cells can prevent telomere loss by aberrantly upregulating telomerase. The zebrafish (Danio rerio) offers multiple experimental manipulation advantages over other vertebrate models and, therefore, it has been recently considered as a potential model for aging, cancer, and regeneration studies. However, it has only partially been exploited to shed light on these fundamental biological processes. The aim of this study was, therefore, to investigate telomere length and telomerase expression and activity in different strains of zebrafish obtained from different stock centres to determine whether they undergo any changes during aging and regeneration. We found that although both telomerase expression and telomere length increased from embryo to adulthood stages, they drastically declined in aged fish despite telomerase activity was detected in different tissues of old fish. In addition, we observed a weaker upregulation of telomerase expression in regenerating fins of old fish, which well correlates with their impaired regeneration capacity. Strikingly, telomeres were elongated or maintained during the fin regeneration process at all ages and after repeated amputations, likely to support high cell proliferation rates. We conclude that the expression of telomerase and telomere length are closely related during the entire life cycle of the fish and that these two parameters can be used as biomarkers of aging in zebrafish. Our results also reveal a direct relationship between the expression of telomerase, telomere length and the efficiency of tissue regeneration.

Ghrelin knockout mice display defective skeletal muscle regeneration and impaired satellite cell self-renewal.

PubMed

Angelino, Elia; Reano, Simone; Bollo, Alessandro; Ferrara, Michele; De Feudis, Marilisa; Sustova, Hana; Agosti, Emanuela; Clerici, Sara; Prodam, Flavia; Tomasetto, Catherine-Laure; Graziani, Andrea; Filigheddu, Nicoletta

2018-05-30

Muscle regeneration depends on satellite cells (SCs), quiescent precursors that, in consequence of injury or pathological states such as muscular dystrophies, activate, proliferate, and differentiate to repair the damaged tissue. A subset of SCs undergoes self-renewal, thus preserving the SC pool and its regenerative potential. The peptides produced by the ghrelin gene, i.e., acylated ghrelin (AG), unacylated ghrelin (UnAG), and obestatin (Ob), affect skeletal muscle biology in several ways, not always with overlapping effects. In particular, UnAG and Ob promote SC self-renewal and myoblast differentiation, thus fostering muscle regeneration. To delineate the endogenous contribution of preproghrelin in muscle regeneration, we evaluated the repair process in Ghrl -/- mice upon CTX-induced injury. Although muscles from Ghrl -/- mice do not visibly differ from WT muscles in term of weight, structure, and SCs content, muscle regeneration after CTX-induced injury is impaired in Ghrl -/- mice, indicating that ghrelin-derived peptides actively participate in muscle repair. Remarkably, the lack of ghrelin gene impacts SC self-renewal during regeneration. Although we cannot discern the specific Ghrl-derived peptide responsible for such activities, these data indicate that Ghrl contributes to a proper muscle regeneration.

Atmospheric pressure plasma accelerates tail regeneration in tadpoles Xenopus laevis

NASA Astrophysics Data System (ADS)

Rivie, A.; Martus, K.; Menon, J.

2017-08-01

Atmospheric pressure plasma is a partially ionized gas composed of neutral and charged particles, including electrons and ions, as well as reactive oxygen species (ROS). Recently, it is utilized as possible therapy in oncology, sterilization, skin diseases, wound healing and tissue regeneration. In this study we focused on effect of plasma exposure on tail regeneration of tadpoles, Xenopus leavis with special emphasis on role of ROS, antioxidant defenses and morphological features of the regenerate. When amputated region of the tail was exposed to the helium plasma it resulted in a faster rate of growth, elevated ROS and increase in antioxidant enzymes in the regenerate compared to that of untreated control. An increase in nitric oxide (free radical) as well as activity of nitric oxide synthase(s) were observed once the cells of the regeneration blastema - a mass of proliferating cells are ready for differentiation. Microscopically the cells of the regenerate of plasma treated tadpoles show altered morphology and characteristics of cellular hypoxia and oxidative stress. We summarize that plasma exposure accelerates the dynamics of wound healing and tail regeneration through its effects on cell proliferation and differentiation as well as angiogenesis mediated through ROS signaling.

Acute stress promotes post-injury brain regeneration in fish.

PubMed

Sinyakov, Michael S; Haimovich, Amihai; Avtalion, Ramy R

2017-12-01

The central nervous system and the immune system, the two major players in homeostasis, operate in the ongoing bidirectional interaction. Stress is the third player that exerts strong effect on these two 'supersystems'; yet, its impact is studied much less. In this work employing carp model, we studied the influence of preliminary stress on neural and immune networks involved in post-injury brain regeneration. The relevant in vivo models of air-exposure stress and precisely directed cerebellum injury have been developed. Neuronal regeneration was evaluated by using specific tracers of cell proliferation and differentiation. Involvement of immune networks was accessed by monitoring the expression of selected T cells markers. Contrast difference between acute and chronic stress manifested in the fact that chronically stressed fish did not survive the brain injury. Neuronal regeneration appeared as a biphasic process whereas involvement of immune system proceeded as a monophasic route. In stressed fish, immune response was fast and accompanied or even preceded neuronal regeneration. In unstressed subjects, immune response took place on the second phase of neuronal regeneration. These findings imply an intrinsic regulatory impact of acute stress on neuronal and immune factors involved in post-injury brain regeneration. Stress activates both neuronal and immune defense mechanisms and thus contributes to faster regeneration. In this context, paradoxically, acute preliminary stress might be considered a distinct asset in speeding up the following post-injury brain regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Ex vivo adenoviral gene transfer of constitutively activated STAT3 reduces post-transplant liver injury and promotes regeneration in a 20% rat partial liver transplant model.

PubMed

Huda, Kamrul A S M; Guo, Lei; Haga, Sanae; Murata, Hiroshi; Ogino, Tetsuya; Fukai, Moto; Yagi, Takahito; Iwagaki, Hiromi; Tanaka, Noriaki; Ozaki, Michitaka

2006-05-01

Signal transducer and activator of transcription-3 (STAT3) is one of the most important transcription factors for liver regeneration. This study was designed to examine the effects of constitutively activated STAT3 (STAT3-C) on post-transplant liver injury and regeneration in a rat 20% partial liver transplant (PLTx) model by ex vivo adenoviral gene transfer. Adenovirus encoding the STAT3-C gene was introduced intraportally into liver grafts and clamped for 30 min during cold preservation. After orthotopic PLTx, liver graft/body weights and serum biochemistry were monitored, and both a histological study and DNA binding assay were performed. STAT3-C protein expression and its binding to DNA in the liver graft were confirmed by Western blotting and electrophoretic mobility shift assay (EMSA), respectively. This treatment modality promoted post-Tx liver regeneration effectively and rapidly. The serum levels of alanine aminotransferase/aspartate aminotransferase (AST/ALT) and bilirubin decreased in rats with STAT3-C. However, albumin (a marker of liver function) did not. Ex vivo gene transfer of STAT3-C to liver grafts reduced post-Tx injury and promoted liver regeneration. Thus, the activation of STAT3 in the liver graft may be a potentially effective clinical strategy for improving the outcome of small-for-size liver transplantation.

Method of treating intermetallic alloy hydrogenation/oxidation catalysts for improved impurity poisoning resistance, regeneration and increased activity

DOEpatents

Wright, Randy B.

1992-01-01

Alternate, successive high temperature oxidation and reduction treatments, in either order, of intermetallic alloy hydrogenation and intermetallic alloy oxidation catalysts unexpectedly improves the impurity poisoning resistance, regeneration capacity and/or activity of the catalysts. The particular alloy, and the final high temperature treatment given alloy (oxidation or reduction) will be chosen to correspond to the function of the catalyst (oxidation or hydrogenation).

Physico-Chemical Characterization of Fine and Ultrafine Particles Emitted during Diesel Particulate Filter Active Regeneration of Euro5 Diesel Vehicles.

PubMed

R'Mili, Badr; Boréave, Antoinette; Meme, Aurelie; Vernoux, Philippe; Leblanc, Mickael; Noël, Ludovic; Raux, Stephane; D'Anna, Barbara

2018-03-06

Diesel particulate filters (DPFs) are commonly employed in modern passenger cars to comply with current particulate matter (PM) emission standards. DPFs requires periodic regeneration to remove the accumulated matter. During the process, high-concentration particles, in both nucleation and accumulation modes, are emitted. Here, we report new information on particle morphology and chemical composition of fine (FPs) and ultrafine particles (UFPs) measured downstream of the DPF during active regeneration of two Euro 5 passenger cars. The first vehicle was equipped with a close-coupled diesel oxidation catalyst (DOC) and noncatalyzed DPF combined with fuel borne catalyst and the second one with DOC and a catalyzed-diesel particle filter (CDPF). Differences in PM emission profiles of the two vehicles were related to different after treatment design, regeneration strategies, and vehicle characteristics and mileage. Particles in the nucleation mode consisted of ammonium bisulfate, sulfate and sulfuric acid, suggesting that the catalyst desulfation is the key process in the formation of UFPs. Larger particles and agglomerates, ranging from 90 to 600 nm, consisted of carbonaceous material (soot and soot aggregates) coated by condensable material including organics, ammonium bisulfate and sulfuric acid. Particle emission in the accumulation mode was due to the reduced filtration efficiency (soot cake oxidation) throughout the regeneration process.

MCG measurement in the environment of active magnetic shield.

PubMed

Yamazaki, K; Kato, K; Kobayashi, K; Igarashi, A; Sato, T; Haga, A; Kasai, N

2004-11-30

MCG (Magnetocardiography) measurement by a SQUID gradiometer was attempted with only active magnetic shielding (active shielding). A three-axis-canceling-coil active shielding system, where three 16-10-16 turns-coil sets were put in the orthogonal directions, produces a homogeneous magnetic field in a considerable volume surrounding the center. Fluxgate sensors were used as the reference sensors of the system. The system can reduce environmental magnetic noise at low frequencies of less than a few Hz, at 50 Hz and at 150 Hz. Reducing such disturbances stabilizes biomagnetic measurement conditions for SQUIDs in the absence of magnetically shielded rooms (MSR). After filtering and averaging the measured MCG data by a first-order SQUID gradiometer with only the active shielding during the daytime, the QRS complex and T wave was clearly presented.

Biodegradability of regenerated cellulose films in soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, L.; Liu, H.; Zheng, L.

1996-12-01

Regenerated cellulose films and a water-resistant film coated with thin Tung oil were prepared by using a cellulose cuoxam solution from pulps of cotton linter, cotton stalk, and wheat straw. They were buried in the soil to test biodegradability. The results showed that viscosity average molecular weight M{sub {eta}}, tensile strength {sigma}{sub b}, and the weight of the degraded films decreased sharply with the progress of degradation time, and the kinetics of decay were discussed. The degradation half-lives t{sub 1/2} of the films in soil at 10--20 C were given to be 30--42 days, and after 2 months the filmsmore » were decomposed into CO{sub 2} and water. The {alpha}-cellulose in soil was more readily biodegraded than hemicellulose, and regenerated cellulose film was more readily biodegraded than kraft paper. Nuclear magnetic resonance and scanning electron micrographs indicated that the biodegradation process of the films was performed through random breakdown of bonds of cellulose macromolecules resulting from the microorganism cleavage.« less

Contaminant removal from enclosed atmospheres by regenerable adsorbents

NASA Technical Reports Server (NTRS)

Goldsmith, R. L.; Mcnulty, K. J.; Freedland, G. M.; Turk, A.; Nwankwo, J.

1974-01-01

A system for removing contaminants from spacecraft atmospheres was studied, which utilizes catalyst-impregnated activated carbon followed by in-situ regeneration by low-temperature catalytic oxidation of the adsorbed contaminants. Platinum was deposited on activated carbon by liquid phase impregnation with chloroplatinic acid, followed by drying and high-temperature reduction. Results were obtained for the seven selected spacecraft contaminants by means of three experimental test systems. The results indicate that the contaminants could be removed by oxidation with very little loss in adsorptive capacity. The advantages of a catalyst-impregnated carbon for oxidative regeneration are found to be significant enough to warrent its use.

Mental Regeneration.

ERIC Educational Resources Information Center

Langer, Jonas

Techniques for developing the potential of culturally deprived people cannot be developed without more knowledge of the basic mechanisms of mental change. Psysiological generation and regeneration are both apparently governed by the same set of mechanisms. Regeneration is possible only when a part of the damaged structure is left, and these…

Nerve–muscle activation by rotating permanent magnet configurations

PubMed Central

Nicholson, Graham M.

2016-01-01

Key points The standard method of magnetic nerve activation using pulses of high current in coils has drawbacks of high cost, high electrical power (of order 1 kW), and limited repetition rate without liquid cooling.Here we report a new technique for nerve activation using high speed rotation of permanent magnet configurations, generating a sustained sinusoidal electric field using very low power (of order 10 W).A high ratio of the electric field gradient divided by frequency is shown to be the key indicator for nerve activation at high frequencies.Activation of the cane toad sciatic nerve and attached gastrocnemius muscle was observed at frequencies as low as 180 Hz for activation of the muscle directly and 230 Hz for curved nerves, but probably not in straight sections of nerve.These results, employing the first prototype device, suggest the opportunity for a new class of small low‐cost magnetic nerve and/or muscle stimulators. Abstract Conventional pulsed current systems for magnetic neurostimulation are large and expensive and have limited repetition rate because of overheating. Here we report a new technique for nerve activation, namely high‐speed rotation of a configuration of permanent magnets. Analytical solutions of the cable equation are derived for the oscillating electric field generated, which has amplitude proportional to the rotation speed. The prototype device built comprised a configuration of two cylindrical magnets with antiparallel magnetisations, made to rotate by interaction between the magnets’ own magnetic field and three‐phase currents in coils mounted on one side of the device. The electric field in a rectangular bath placed on top of the device was both numerically evaluated and measured. The ratio of the electric field gradient on frequency was approximately 1 V m−2 Hz−1 near the device. An exploratory series of physiological tests was conducted on the sciatic nerve and attached gastrocnemius muscle of the cane toad

Combination of small RNAs for skeletal muscle regeneration.

PubMed

Kim, NaJung; Yoo, James J; Atala, Anthony; Lee, Sang Jin

2016-03-01

Selectively controlling the expression of the target genes through RNA interference (RNAi) has significant therapeutic potential for injuries or diseases of tissues. We used this strategy to accelerate and enhance skeletal muscle regeneration for the treatment of muscular atrophy. In this study, we used myostatin small interfering (si)RNA (siGDF-8), a major inhibitory factor in the development and postnatal regeneration of skeletal muscle and muscle-specific microRNAs (miR-1 and -206) to further accelerate muscle regeneration. This combination of 3 small RNAs significantly improved the gene expression of myogenic regulatory factors in vitro, suggesting myogenic activation. Moreover, cell proliferation and myotube formation improved without compromising each other, which indicates the myogenic potential of this combination of small RNAs. The recovery of chemically injured tibialis anterior muscles in rats was significantly accelerated, both functionally and structurally. This novel combination of siRNA and miRNAs has promising therapeutic potential to improve in situ skeletal muscle regeneration. © FASEB.

mTOR is necessary for proper satellite cell activity and skeletal muscle regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Pengpeng; Department of Animal Sciences, Purdue University, West Lafayette, IN 47907; Liang, Xinrong

The serine/threonine kinase mammalian target of rapamycin (mTOR) is a key regulator of protein synthesis, cell proliferation and energy metabolism. As constitutive deletion of Mtor gene results in embryonic lethality, the function of mTOR in muscle stem cells (satellite cells) and skeletal muscle regeneration remains to be determined. In this study, we established a satellite cell specific Mtor conditional knockout (cKO) mouse model by crossing Pax7{sup CreER} and Mtor{sup flox/flox} mice. Skeletal muscle regeneration after injury was severely compromised in the absence of Mtor, indicated by increased number of necrotic myofibers infiltrated by Evans blue dye, and reduced number andmore » size of regenerated myofibers in the Mtor cKO mice compared to wild type (WT) littermates. To dissect the cellular mechanism, we analyzed satellite cell-derived primary myoblasts grown on single myofibers or adhered to culture plates. The Mtor cKO myoblasts exhibited defective proliferation and differentiation kinetics when compared to myoblasts derived from WT littermates. At the mRNA and protein levels, the Mtor cKO myoblasts expressed lower levels of key myogenic determinant genes Pax7, Myf5, Myod, Myog than did the WT myoblasts. These results suggest that mTOR is essential for satellite cell function and skeletal muscle regeneration through controlling the expression of myogenic genes. - Highlights: • Pax7{sup CreER} was used to delete Mtor gene in satellite cells. • Satellite cell specific deletion of Mtor impairs muscle regeneration. • mTOR is necessary for satellite cell proliferation and differentiation. • Deletion of Mtor leads to reduced expression of key myogenic genes.« less

Activation of the unfolded protein response promotes axonal regeneration after peripheral nerve injury

PubMed Central

Oñate, Maritza; Catenaccio, Alejandra; Martínez, Gabriela; Armentano, Donna; Parsons, Geoffrey; Kerr, Bredford; Hetz, Claudio; Court, Felipe A.

2016-01-01

Although protein-folding stress at the endoplasmic reticulum (ER) is emerging as a driver of neuronal dysfunction in models of spinal cord injury and neurodegeneration, the contribution of this pathway to peripheral nerve damage remains poorly explored. Here we targeted the unfolded protein response (UPR), an adaptive reaction against ER stress, in mouse models of sciatic nerve injury and found that ablation of the transcription factor XBP1, but not ATF4, significantly delay locomotor recovery. XBP1 deficiency led to decreased macrophage recruitment, a reduction in myelin removal and axonal regeneration. Conversely, overexpression of XBP1s in the nervous system in transgenic mice enhanced locomotor recovery after sciatic nerve crush, associated to an improvement in key pro-regenerative events. To assess the therapeutic potential of UPR manipulation to axonal regeneration, we locally delivered XBP1s or an shRNA targeting this transcription factor to sensory neurons of the dorsal root ganglia using a gene therapy approach and found an enhancement or reduction of axonal regeneration in vivo, respectively. Our results demonstrate a functional role of specific components of the ER proteostasis network in the cellular changes associated to regeneration and functional recovery after peripheral nerve injury. PMID:26906090

Magnetic Oscillations Mark Sites of Magnetic Transients in an Acoustically Active Flare

NASA Astrophysics Data System (ADS)

Lindsey, Charles A.; Donea, A.; Hudson, H. S.; Martinez Oliveros, J.; Hanson, C.

2011-05-01

The flare of 2011 February 15, in NOAA AR11158, was the first acoustically active flare of solar cycle 24, and the first observed by the Solar Dynamics Observatory (SDO). It was exceptional in a number of respects (Kosovichev 2011a,b). Sharp ribbon-like transient Doppler, and magnetic signatures swept over parts of the active region during the impulsive phase of the flare. We apply seismic holography to a 2-hr time series of HMI observations encompassing the flare. The acoustic source distribution appears to have been strongly concentrated in a single highly compact penumbral region in which the continuum-intensity signature was unusually weak. The line-of-sight magnetic transient was strong in parts of the active region, but relatively weak in the seismic-source region. On the other hand, the neighbourhoods of the regions visited by the strongest magnetic transients maintained conspicuous 5-minutes-period variations in the line of sight magnetic signature for the full 2-hr duration of the time series, before the flare as well as after. We apply standard helioseismic control diagnostics for clues as to the physics underlying 5-minute magnetic oscillations in regions conducive to magnetic transients during a flare and consider the prospective development of this property as an indicator of flare potentiality on some time scale. We make use of high-resolution data from AIA, using diffracted images where necessary to obtain good photometry where the image is otherwise saturated. This is relevant to seismic emission driven by thick-target heating in the absence of back-warming. We also use RHESSI imaging spectroscopy to compare the source distributions of HXR and seismic emission.

Activation of Schwann cells in vitro by magnetic nanocomposites via applied magnetic field.

PubMed

Liu, Zhongyang; Huang, Liangliang; Liu, Liang; Luo, Beier; Liang, Miaomiao; Sun, Zhen; Zhu, Shu; Quan, Xin; Yang, Yafeng; Ma, Teng; Huang, Jinghui; Luo, Zhuojing

2015-01-01

Schwann cells (SCs) are attractive seed cells in neural tissue engineering, but their application is limited by attenuated biological activities and impaired functions with aging. Therefore, it is important to explore an approach to enhance the viability and biological properties of SCs. In the present study, a magnetic composite made of magnetically responsive magnetic nanoparticles (MNPs) and a biodegradable chitosan-glycerophosphate polymer were prepared and characterized. It was further explored whether such magnetic nanocomposites via applied magnetic fields would regulate SC biological activities. The magnetization of the magnetic nanocomposite was measured by a vibrating sample magnetometer. The compositional characterization of the magnetic nanocomposite was examined by Fourier-transform infrared and X-ray diffraction. The tolerance of SCs to the magnetic fields was tested by flow-cytometry assay. The proliferation of cells was examined by a 5-ethynyl-2-deoxyuridine-labeling assay, a PrestoBlue assay, and a Live/Dead assay. Messenger ribonucleic acid of BDNF, GDNF, NT-3, and VEGF in SCs was assayed by quantitative real-time polymerase chain reaction. The amount of BDNF, GDNF, NT-3, and VEGF secreted from SCs was determined by enzyme-linked immunosorbent assay. It was found that magnetic nanocomposites containing 10% MNPs showed a cross-section diameter of 32.33±1.81 µm, porosity of 80.41%±0.72%, and magnetization of 5.691 emu/g at 8 kOe. The 10% MNP magnetic nanocomposites were able to support cell adhesion and spreading and further promote proliferation of SCs under magnetic field exposure. Interestingly, a magnetic field applied through the 10% MNP magnetic scaffold significantly increased the gene expression and protein secretion of BDNF, GDNF, NT-3, and VEGF. This work is the first stage in our understanding of how to precisely regulate the viability and biological properties of SCs in tissue-engineering grafts, which combined with additional

Molecular and Cellular Mechanisms of Axonal Regeneration After Spinal Cord Injury*

PubMed Central

van Niekerk, Erna A.; Tuszynski, Mark H.; Lu, Paul; Dulin, Jennifer N.

2016-01-01

Following axotomy, a complex temporal and spatial coordination of molecular events enables regeneration of the peripheral nerve. In contrast, multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration in the central nervous system. In this review, we examine the current understanding of differences in protein expression and post-translational modifications, activation of signaling networks, and environmental cues that may underlie the divergent regenerative capacity of central and peripheral axons. We also highlight key experimental strategies to enhance axonal regeneration via modulation of intraneuronal signaling networks and the extracellular milieu. Finally, we explore potential applications of proteomics to fill gaps in the current understanding of molecular mechanisms underlying regeneration, and to provide insight into the development of more effective approaches to promote axonal regeneration following injury to the nervous system. PMID:26695766

Shock wave treatment improves nerve regeneration in the rat.

PubMed

Mense, Siegfried; Hoheisel, Ulrich

2013-05-01

The aims of the experiments were to: (1) determine whether low-energy shock wave treatment accelerates the recovery of muscle sensitivity and functionality after a nerve lesion; and (2) assess the effect of shock waves on the regeneration of injured nerve fibers. After compression of a muscle nerve in rats the effects of shock wave treatment on the sequelae of the lesion were tested. In non-anesthetized animals, pressure pain thresholds and exploratory activity were determined. The influence of the treatment on the distance of nerve regeneration was studied in immunohistochemical experiments. Both behavioral and immunohistochemical data show that shock wave treatment accelerates the recovery of muscle sensitivity and functionality and promotes regeneration of injured nerve fibers. Treatment with focused shock waves induces an improvement of nerve regeneration in a rodent model of nerve compression. Copyright © 2012 Wiley Periodicals, Inc.

Perspectives on human regeneration

PubMed Central

Stark, James F.

2018-01-01

Regeneration is a concept that has fascinated humans for centuries. Whether we have been trying to bring things back to life, extract additional resources from the world, or remodel our living spaces—domestic and urban—it is often presented as an unproblematic force for good. But what exactly does it mean to regenerate a body, mind or space? This paper, which introduces a collection of contributions on the theme of human regeneration, explores the limits and possibilities of regeneration as a conceptual tool for understanding the biological realm. What does it mean to be regenerated? How can a scholarly focus on this concept enrich our histories of bodies, ageing, disability and science, technology and medicine? As a secondary goal, I identify two distinct aspects of regeneration—'hard' and 'soft' regeneration—which concern the medical and social elements of regeneration respectively. By recognising that everything from cosmetics and fictions to prosthetics and organs grown in vitro display a combination of 'hard' and 'soft' elements, we are better placed to understand that the biological and social must be considered in consort for us to fully appreciate the meanings and practices that underpin multiple forms of human regeneration. PMID:29910957

The Limit of Magnetic-Shear Energy in Solar Active Regions

NASA Technical Reports Server (NTRS)

Moore, Ronald; Falconer, David; Sterling, Alphonse

2012-01-01

It has been found previously, by measuring from active-region magnetograms a proxy of the free energy in the active region's magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region's magnetic flux content, and (2) that most active regions are near this limit when their field explodes in a coronal mass ejection/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy-limit line in (flux content, free-energy proxy) phase space. Here, we present evidence that specifies the underlying magnetic condition that gives rise to the free-energy limit and the accompanying main sequence of explosive active regions. Using a suitable free-energy proxy measured from vector magnetograms of 44 active regions, we find evidence that (1) in active regions at and near their free-energy limit, the ratio of magnetic-shear free energy to the non-free magnetic energy the potential field would have is of the order of one in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free-energy limit. Evidently, most active regions in which this core-field energy ratio is much less than one cannot be triggered to explode; as this ratio approaches one, most active regions become capable of exploding; and when this ratio is one, most active regions are compelled to explode.

The Limit of Magnetic-Shear Energy in Solar Active Regions

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Falconer, David A.; Sterling, Alphonse C.

2013-01-01

It has been found previously, by measuring from active ]region magnetograms a proxy of the free energy in the active region fs magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) that most active regions are near this limit when their field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main ]sequence path bordering the free ]energy ]limit line in (flux content, free ]energy proxy) phase space. Here we present evidence that specifies the underlying magnetic condition that gives rise to the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free energy proxy measured from vector magnetograms of 44 active regions, we find evidence that (1) in active regions at and near their free ]energy limit, the ratio of magnetic ]shear free energy to the non ]free magnetic energy the potential field would have is of order 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. Evidently, most active regions in which this core ]field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1, most active regions are compelled to explode.

The Effects of Magnetic Activity on Lithium-Inferred Ages of Stars

NASA Astrophysics Data System (ADS)

Juarez, Aaron J.; Cargile, Phillip A.; James, David J.; Stassun, Keivan G.

2014-08-01

In this project, we investigate the effects of magnetic activity on the Lithium Depletion Boundary (LDB) to recalibrate the measured ages for star clusters, using the open cluster Blanco 1 as a pilot study. We apply the LDB technique on low-mass Pre-Main-Sequence (PMS) stars to derive an accurate age for Blanco 1, and we consider the effect of magnetic activity on this inferred age. Although observations have shown that magnetic activity directly affects stellar radius and temperature, most PMS models do not include the effects of magnetic activity on stellar properties. Since the lithium abundance of a star depends on its radius and temperature, we expect that LDB ages are affected by magnetic activity. After empirically accounting for the effects of magnetic activity, we find the age of Blanco 1 to be ~100 Myr, which is ~30 Myr younger than the standard LDB age of ~130 Myr.

Platelets prime hematopoietic–vascular niche to drive angiocrine-mediated liver regeneration

PubMed Central

Shido, Koji; Chavez, Deebly; Cao, Zhongwei; Ko, Jane L; Rafii, Shahin; Ding, Bi-Sen

2017-01-01

In mammals, the livers regenerate after chemical injury or resection of hepatic lobe by hepatectomy. How liver regeneration is initiated after mass loss remains to be defined. Here we report that following liver injury, activated platelets deploy SDF-1 and VEGF-A to stimulate CXCR7+ liver sinusoidal endothelial cell (LSEC) and VEGFR1+ myeloid cell, orchestrating hepatic regeneration. After carbon tetrachloride injection or hepatectomy, platelets and CD11b+VEGFR1+ myeloid cells were recruited to LSECs, and liver regeneration in both models was impaired in thrombopoietin-deficient (Thpo−/−) mice repressing production of circulating platelets. This impeded regeneration phenotype was recapitulated in mice with either conditional ablation of Cxcr7 in LSEC (Cxcr7iΔ/iΔ) or Vegfr1 in myeloid cell (Vegfr1lysM/lysM). Both Vegfr1lysM/lysM and Cxcr7iΔ/iΔ mice exhibited suppressed expression of hepatocyte growth factor and Wnt2, two crucial trophogenic angiocrine factors instigating hepatocyte propagation. Of note, administration of recombinant thrombopoietin restored the prohibited liver regeneration in the tested genetic models. As such, our data suggest that platelets and myeloid cells jointly activate the vascular niche to produce pro-regenerative endothelial paracrine/angiocrine factors. Modulating this ‘hematopoietic–vascular niche’ might help to develop regenerative therapy strategy for hepatic disorders. PMID:29201496

Alternative cells for regeneration.

PubMed

Slack, Jonathan M W

2012-04-17

Normally, in fish fin regeneration, bone regenerates from bone. But what happens when there is no bone? Singh et al. (2012) show in this issue of Developmental Cell that the bony rays still regenerate from an alternative cell source. Copyright © 2012 Elsevier Inc. All rights reserved.

Optimization for zeolite regeneration and nitrogen removal performance of a hypochlorite-chloride regenerant.

PubMed

Zhang, Wei; Zhou, Zhen; An, Ying; Du, Silu; Ruan, Danian; Zhao, Chengyue; Ren, Ning; Tian, Xiaoce

2017-07-01

Simultaneous zeolites regeneration and nitrogen removal were investigated by using a mixed solution of NaClO and NaCl (NaClO-NaCl solution), and effects of the regenerant on ammonium removal performance and textural properties of zeolites were analyzed by long-term adsorption and regeneration operations. Mixed NaClO-NaCl solution removed more NH 4 + exchanged on zeolites and converted more of them to nitrogen than using NaClO or NaCl solution alone. Response surface methodological analysis indicated that molar ratio of hypochlorite and nitrogen (ClO - /N), NaCl concentration and pH value all had significant effects on zeolites regeneration and NH 4 + conversion to nitrogen, and the optimum condition was obtained at ClO - /N of 1.75, NaCl concentration of 20 g/L and pH of 10.0. Zeolites regenerated by mixed NaClO-NaCl solution showed higher ammonium adsorption rate and lower capacity than unused zeolites. Zeolites and the regeneration solution were both effective even after 20 cycles of use. Composition and morphological analysis revealed that the main mineral species and surface morphology of zeolites before and after NaClO-NaCl regeneration were unchanged. Textural analysis indicated that NaClO-NaCl regeneration leads to an increased surface area of zeolites, especially the microporosity. The results indicated that NaClO-NaCl regeneration is an attractive method to achieve sustainable removal of nitrogen from wastewater through zeolite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Live imaging reveals the progenitors and cell dynamics of limb regeneration

PubMed Central

Alwes, Frederike; Enjolras, Camille; Averof, Michalis

2016-01-01

Regeneration is a complex and dynamic process, mobilizing diverse cell types and remodelling tissues over long time periods. Tracking cell fate and behaviour during regeneration in active adult animals is especially challenging. Here, we establish continuous live imaging of leg regeneration at single-cell resolution in the crustacean Parhyale hawaiensis. By live recordings encompassing the first 4-5 days after amputation, we capture the cellular events that contribute to wound closure and morphogenesis of regenerating legs with unprecedented resolution and temporal detail. Using these recordings we are able to track cell lineages, to generate fate maps of the blastema and to identify the progenitors of regenerated epidermis. We find that there are no specialized stem cells for the epidermis. Most epidermal cells in the distal part of the leg stump proliferate, acquire new positional values and contribute to new segments in the regenerating leg. DOI: http://dx.doi.org/10.7554/eLife.19766.001 PMID:27776632

The Drosophila Duox maturation factor is a key component of a positive feedback loop that sustains regeneration signaling.

PubMed

Khan, Sumbul Jawed; Abidi, Syeda Nayab Fatima; Skinner, Andrea; Tian, Yuan; Smith-Bolton, Rachel K

2017-07-01

Regenerating tissue must initiate the signaling that drives regenerative growth, and sustain that signaling long enough for regeneration to complete. How these key signals are sustained is unclear. To gain a comprehensive view of the changes in gene expression that occur during regeneration, we performed whole-genome mRNAseq of actively regenerating tissue from damaged Drosophila wing imaginal discs. We used genetic tools to ablate the wing primordium to induce regeneration, and carried out transcriptional profiling of the regeneration blastema by fluorescently labeling and sorting the blastema cells, thus identifying differentially expressed genes. Importantly, by using genetic mutants of several of these differentially expressed genes we have confirmed that they have roles in regeneration. Using this approach, we show that high expression of the gene moladietz (mol), which encodes the Duox-maturation factor NIP, is required during regeneration to produce reactive oxygen species (ROS), which in turn sustain JNK signaling during regeneration. We also show that JNK signaling upregulates mol expression, thereby activating a positive feedback signal that ensures the prolonged JNK activation required for regenerative growth. Thus, by whole-genome transcriptional profiling of regenerating tissue we have identified a positive feedback loop that regulates the extent of regenerative growth.

The Drosophila Duox maturation factor is a key component of a positive feedback loop that sustains regeneration signaling

PubMed Central

Skinner, Andrea; Tian, Yuan

2017-01-01

Regenerating tissue must initiate the signaling that drives regenerative growth, and sustain that signaling long enough for regeneration to complete. How these key signals are sustained is unclear. To gain a comprehensive view of the changes in gene expression that occur during regeneration, we performed whole-genome mRNAseq of actively regenerating tissue from damaged Drosophila wing imaginal discs. We used genetic tools to ablate the wing primordium to induce regeneration, and carried out transcriptional profiling of the regeneration blastema by fluorescently labeling and sorting the blastema cells, thus identifying differentially expressed genes. Importantly, by using genetic mutants of several of these differentially expressed genes we have confirmed that they have roles in regeneration. Using this approach, we show that high expression of the gene moladietz (mol), which encodes the Duox-maturation factor NIP, is required during regeneration to produce reactive oxygen species (ROS), which in turn sustain JNK signaling during regeneration. We also show that JNK signaling upregulates mol expression, thereby activating a positive feedback signal that ensures the prolonged JNK activation required for regenerative growth. Thus, by whole-genome transcriptional profiling of regenerating tissue we have identified a positive feedback loop that regulates the extent of regenerative growth. PMID:28753614

A Comprehensive Transcriptomic and Proteomic Analysis of Hydra Head Regeneration

PubMed Central

Petersen, Hendrik O.; Höger, Stefanie K.; Looso, Mario; Lengfeld, Tobias; Kuhn, Anne; Warnken, Uwe; Nishimiya-Fujisawa, Chiemi; Schnölzer, Martina; Krüger, Marcus; Özbek, Suat; Simakov, Oleg; Holstein, Thomas W.

2015-01-01

The cnidarian freshwater polyp Hydra sp. exhibits an unparalleled regeneration capacity in the animal kingdom. Using an integrative transcriptomic and stable isotope labeling by amino acids in cell culture proteomic/phosphoproteomic approach, we studied stem cell-based regeneration in Hydra polyps. As major contributors to head regeneration, we identified diverse signaling pathways adopted for the regeneration response as well as enriched novel genes. Our global analysis reveals two distinct molecular cascades: an early injury response and a subsequent, signaling driven patterning of the regenerating tissue. A key factor of the initial injury response is a general stabilization of proteins and a net upregulation of transcripts, which is followed by a subsequent activation cascade of signaling molecules including Wnts and transforming growth factor (TGF) beta-related factors. We observed moderate overlap between the factors contributing to proteomic and transcriptomic responses suggesting a decoupled regulation between the transcriptional and translational levels. Our data also indicate that interstitial stem cells and their derivatives (e.g., neurons) have no major role in Hydra head regeneration. Remarkably, we found an enrichment of evolutionarily more recent genes in the early regeneration response, whereas conserved genes are more enriched in the late phase. In addition, genes specific to the early injury response were enriched in transposon insertions. Genetic dynamicity and taxon-specific factors might therefore play a hitherto underestimated role in Hydra regeneration. PMID:25841488

Effect of JNK inhibitor SP600125 on hair cell regeneration in zebrafish (Danio rerio) larvae

PubMed Central

Sun, Shaoyang; Wang, Xu; Li, Wenyan; Li, Huawei

2016-01-01

The c-Jun amino-terminal kinase (JNK) proteins are a subgroup of the mitogen-activated protein kinase family. They play a complex role in cell proliferation, survival, and apoptosis. Here, we report a novel role of JNK signalling in hair cell regeneration. We eliminated hair cells of 5-day post-fertilization zebrafish larvae using neomycin followed by JNK inhibition with SP600125. JNK inhibition strongly decreased the number of regenerated hair cells in response to neomycin damage. These changes were associated with reduced proliferation. JNK inhibition also increased cleaved caspase-3 activity and induced apoptosis in regenerating neuromasts. Finally, JNK inhibition with SP600125 decreased the expression of genes related to Wnt. Over-activation of the Wnt signalling pathway partly rescued the hair cell regeneration defects induced by JNK inhibition. Together, our findings provide novel insights into the function of JNK and show that JNK inhibition blocks hair cell regeneration by controlling the Wnt signalling pathway. PMID:27438150

Method of treating intermetallic alloy hydrogenation/oxidation catalysts for improved impurity poisoning resistance, regeneration and increased activity

DOEpatents

Wright, R.B.

1992-01-14

Alternate, successive high temperature oxidation and reduction treatments, in either order, of intermetallic alloy hydrogenation and intermetallic alloy oxidation catalysts unexpectedly improves the impurity poisoning resistance, regeneration capacity and/or activity of the catalysts. The particular alloy, and the final high temperature treatment given alloy (oxidation or reduction) will be chosen to correspond to the function of the catalyst (oxidation or hydrogenation). 23 figs.

Principles of natural regeneration

Treesearch

1989-01-01

To maximize chances of successful regeneration, carefully consider the following regeneration principles. Harvesting alone does not guarantee that the desired species will be established. The conditions required for the initial establishment and early growth of the desired species largely determine what regeneration method you should use and any supplemental treatments...

β-Catenin acts in a position-independent regeneration response in the simple eumetazoan Hydra.

PubMed

Gufler, S; Artes, B; Bielen, H; Krainer, I; Eder, M-K; Falschlunger, J; Bollmann, A; Ostermann, T; Valovka, T; Hartl, M; Bister, K; Technau, U; Hobmayer, B

2018-01-15

Wnt/β-Catenin signaling plays crucial roles in regenerative processes in eumetazoans. It also acts in regeneration and axial patterning in the simple freshwater polyp Hydra, whose morphallactic regenerative capacity is unparalleled in the animal kingdom. Previous studies have identified β-catenin as an early response gene activated within the first 30min in Hydra head regeneration. Here, we have studied the role of β-Catenin in more detail. First, we show that nuclear β-Catenin signaling is required for head and foot regeneration. Loss of nuclear β-Catenin function blocks head and foot regeneration. Transgenic Hydra tissue, in which β-Catenin is over-expressed, regenerates more heads and feet. In addition, we have identified a set of putative β-Catenin target genes by transcriptional profiling, and these genes exhibit distinct expression patterns in the hypostome, in the tentacles, or in an apical gradient in the body column. All of them are transcriptionally up-regulated in the tips of early head and foot regenerates. In foot regenerates, this is a transient response, and expression starts to disappear after 12-36h. ChIP experiments using an anti-HydraTcf antibody show Tcf binding at promoters of these targets. We propose that gene regulatory β-Catenin activity in the pre-patterning phase is generally required as an early regeneration response. When regenerates are blocked with iCRT14, initial local transcriptional activation of β-catenin and the target genes occurs, and all these genes remain upregulated at the site of both head and foot regeneration for the following 2-3 days. This indicates that the initial regulatory network is followed by position-specific programs that inactivate fractions of this network in order to proceed to differentiation of head or foot structures. brachyury1 (hybra1) has previously been described as early response gene in head and foot regeneration. The HyBra1 protein, however, appears in head regenerating tips not earlier

Regeneration efficiency, shuttle heat loss and thermal conductivity in epoxy-composite annualr gap regenerators from 4K to 80K

NASA Technical Reports Server (NTRS)

Myrtle, K.; Cygax, S.; Plateel, C.; Winter, C.

1983-01-01

A test apparatus designed to simulate a section of a Stirling cycle cryocooler was built. Measurements of regeneration efficiency, shuttle heat loss and thermal conductivity reported for several regenerator test sections. The test composites were epoxy glass, epoxy glass with lead particles, epoxy glass with activated charcoal and epoxy graphite. Losses measured for these materials were approximately the same. Losses are in good agreement with those calculated theoretically for an epoxy glass (C-10) composite. The implications of these results on cryocooler design are discussed.

Bioactive Scaffolds for Regeneration of Cartilage and Subchondral Bone Interface

PubMed Central

Deng, Cuijun; Zhu, Huiying; Li, Jiayi; Feng, Chun; Yao, Qingqiang; Wang, Liming; Chang, Jiang; Wu, Chengtie

2018-01-01

The cartilage lesion resulting from osteoarthritis (OA) always extends into subchondral bone. It is of great importance for simultaneous regeneration of two tissues of cartilage and subchondral bone. 3D-printed Sr5(PO4)2SiO4 (SPS) bioactive ceramic scaffolds may achieve the aim of regenerating both of cartilage and subchondral bone. We hypothesized that strontium (Sr) and silicon (Si) ions released from SPS scaffolds play a crucial role in osteochondral defect reconstruction. Methods: SPS bioactive ceramic scaffolds were fabricated by a 3D-printing method. The SEM and ICPAES were used to investigate the physicochemical properties of SPS scaffolds. The proliferation and maturation of rabbit chondrocytes stimulated by SPS bioactive ceramics were measured in vitro. The stimulatory effect of SPS scaffolds for cartilage and subchondral bone regeneration was investigated in vivo. Results: SPS scaffolds significantly stimulated chondrocyte proliferation, and SPS extracts distinctly enhanced the maturation of chondrocytes and preserved chondrocytes from OA. SPS scaffolds markedly promoted the regeneration of osteochondral defects. The complex interface microstructure between cartilage and subchondral bone was obviously reconstructed. The underlying mechanism may be related to Sr and Si ions stimulating cartilage regeneration by activating HIF pathway and promoting subchondral bone reconstruction through activating Wnt pathway, as well as preserving chondrocytes from OA via inducing autophagy and inhibiting hedgehog pathway. Conclusion: Our findings suggest that SPS scaffolds can help osteochondral defect reconstruction and well reconstruct the complex interface between cartilage and subchondral bone, which represents a promising strategy for osteochondral defect regeneration. PMID:29556366

The Maximum Free Magnetic Energy Allowed in a Solar Active Region

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Falconer, David A.

2009-01-01

Two whole-active-region magnetic quantities that can be measured from a line-of-sight magnetogram are (sup L) WL(sub SG), a gauge of the total free energy in an active region's magnetic field, and sup L(sub theta), a measure of the active region's total magnetic flux. From these two quantities measured from 1865 SOHO/MDI magnetograms that tracked 44 sunspot active regions across the 0.5 R(sub Sun) central disk, together with each active region's observed production of CMEs, X flares, and M flares, Falconer et al (2009, ApJ, submitted) found that (1) active regions have a maximum attainable free magnetic energy that increases with the magnetic size (sup L) (sub theta) of the active region, (2) in (Log (sup L)WL(sub SG), Log(sup L) theta) space, CME/flare-productive active regions are concentrated in a straight-line main sequence along which the free magnetic energy is near its upper limit, and (3) X and M flares are restricted to large active regions. Here, from (a) these results, (b) the observation that even the greatest X flares produce at most only subtle changes in active region magnetograms, and (c) measurements from MSFC vector magnetograms and from MDI line-of-sight magnetograms showing that practically all sunspot active regions have nearly the same area-averaged magnetic field strength: =- theta/A approximately equal to 300 G, where theta is the active region's total photospheric flux of field stronger than 100 G and A is the area of that flux, we infer that (1) the maximum allowed ratio of an active region's free magnetic energy to its potential-field energy is 1, and (2) any one CME/flare eruption releases no more than a small fraction (less than 10%) of the active region's free magnetic energy. This work was funded by NASA's Heliophysics Division and NSF's Division of Atmospheric Sciences.