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Sample records for regeneration blastema extract

  1. The blastema and epimorphic regeneration in mammals.

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    Seifert, Ashley W; Muneoka, Ken

    2018-01-15

    Studying regeneration in animals where and when it occurs is inherently interesting and a challenging research topic within developmental biology. Historically, vertebrate regeneration has been investigated in animals that display enhanced regenerative abilities and we have learned much from studying organ regeneration in amphibians and fish. From an applied perspective, while regeneration biologists will undoubtedly continue to study poikilothermic animals (i.e., amphibians and fish), studies focused on homeotherms (i.e., mammals and birds) are also necessary to advance regeneration biology. Emerging mammalian models of epimorphic regeneration are poised to help link regenerative biology and regenerative medicine. The regenerating rodent digit tip, which parallels human fingertip regeneration, and the regeneration of large circular defects through the ear pinna in spiny mice and rabbits, provide tractable, experimental systems where complex tissue structures are regrown through blastema formation and morphogenesis. Using these models as examples, we detail similarities and differences between the mammalian blastema and its classical counterpart to arrive at a broad working definition of a vertebrate regeneration blastema. This comparison leads us to conclude that regenerative failure is not related to the availability of regeneration-competent progenitor cells, but is most likely a function of the cellular response to the microenvironment that forms following traumatic injury. Recent studies demonstrating that targeted modification of this microenvironment can restrict or enhance regenerative capabilities in mammals helps provide a roadmap for eventually pushing the limits of human regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. The axolotl limb blastema: cellular and molecular mechanisms driving blastema formation and limb regeneration in tetrapods

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    McCusker, Catherine; Bryant, Susan V.

    2015-01-01

    Abstract The axolotl is one of the few tetrapods that are capable of regenerating complicated biological structures, such as complete limbs, throughout adulthood. Upon injury the axolotl generates a population of regeneration‐competent limb progenitor cells known as the blastema, which will grow, establish pattern, and differentiate into the missing limb structures. In this review we focus on the crucial early events that occur during wound healing, the neural−epithelial interactions that drive the formation of the early blastema, and how these mechanisms differ from those of other species that have restricted regenerative potential, such as humans. We also discuss how the presence of cells from the different axes of the limb is required for the continued growth and establishment of pattern in the blastema as described in the polar coordinate model, and how this positional information is reprogrammed in blastema cells during regeneration. Multiple cell types from the mature limb stump contribute to the blastema at different stages of regeneration, and we discuss the contribution of these types to the regenerate with reference to whether they are “pattern‐forming” or “pattern‐following” cells. Lastly, we explain how an engineering approach will help resolve unanswered questions in limb regeneration, with the goal of translating these concepts to developing better human regenerative therapies. PMID:27499868

  3. The Urodele Limb Regeneration Blastema: The Cell Potential

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    Kenyon S. Tweedell

    2010-01-01

    Full Text Available The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of progenitor cells derived from tissues of the amputation site, with limited developmental potential, plus various stem cells with multipotent abilities. Many specialized cells, bone, cartilage, muscle, and Schwann cells, at the injury site undergo dedifferentiation to a progenitor state and maintain their cell lineage as they redifferentiate in the regenerate. Muscle satellite reserve stem cells that are active in repair of injured muscle may also dedifferentiate and contribute new muscle cells to the limb blastema. Other cells from the dermis act as multipotent stem cells that replenish dermal fibroblasts and differentiate into cartilage. The blastema primordium is a self-organized, equipotential system, but at the cellular level can compensate for specific cell loss. It is able to induce dedifferentiation of introduced exogenous cells and such cells may be transformed into new cell types. Indigenous cells of the blastema associated with amputated tissues may also transform or possibly transdifferentiate into new cell types. The blastema is a microenvironment that enables dedifferentiation, redifferentiation, transdifferentiation, and stem cell activation, leading to progenitor cells of the limb regenerate.

  4. Blood vessel formation during tail regeneration in the leopard gecko (Eublepharis macularius): The blastema is not avascular.

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    Payne, Samantha L; Peacock, Hanna M; Vickaryous, Matthew K

    2017-03-01

    Unique among amniotes, many lizards are able to self-detach (autotomize) their tail and then regenerate a replacement. Tail regeneration involves the formation of a blastema, an accumulation of proliferating cells at the site of autotomy. Over time, cells of the blastema give rise to most of the tissues in the replacement tail. In non-amniotes capable of regenerating (such as urodeles and some teleost fish), the blastema is reported to be essentially avascular until tissue differentiation takes place. For tail regenerating lizards less is known. Here, we investigate neovascularization during tail regeneration in the leopard gecko (Eublepharis macularius). We demonstrate that the gecko tail blastema is not an avascular structure. Beginning with the onset of regenerative outgrowth, structurally mature (mural cell supported) blood vessels are found within the blastema. Although the pattern of blood vessel distribution in the regenerate tail differs from that of the original, a hierarchical network is established, with vessels of varying luminal diameters and wall thicknesses. Using immunostaining, we determine that blastema outgrowth and tissue differentiation is characterized by a dynamic interplay between the pro-angiogenic protein vascular endothelial growth factor (VEGF) and the anti-angiogenic protein thrombospondin-1 (TSP-1). VEGF-expression is initially widespread, but diminishes as tissues differentiate. In contrast, TSP-1 expression is initially restricted but becomes more abundant as VEGF-expression wanes. We predict that variation in the neovascular response observed between different regeneration-competent species likely relates to the volume of the blastema. J. Morphol. 278:380-389, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Reactivation of larval keratin gene (krt62.L) in blastema epithelium during Xenopus froglet limb regeneration.

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    Satoh, Akira; Mitogawa, Kazumasa; Saito, Nanami; Suzuki, Miyuki; Suzuki, Ken-Ichi T; Ochi, Haruki; Makanae, Aki

    2017-12-15

    Limb regeneration is considered a form of limb redevelopment because of the molecular and morphological similarities. Forming a regeneration blastema is, in essence, creating a developing limb bud in an adult body. This reactivation of a developmental process in a mature body is worth studying. Xenopus laevis has a biphasic life cycle that involves distinct larval and adult stages. These distinct developmental stages are useful for investigating the reactivation of developmental processes in post-metamorphic frogs (froglets). In this study, we focused on the re-expression of a larval gene (krt62.L) during Xenopus froglet limb regeneration. Recently renamed krt62.L, this gene was known as the larval keratin (xlk) gene, which is specific to larval-tadpole stages. During limb regeneration in a froglet, krt62.L was re-expressed in a basal layer of blastema epithelium, where adult-specific keratin (Krt12.6.S) expression was also observable. Nerves produce important regulatory factors for amphibian limb regeneration, and also play a role in blastema formation and maintenance. The effect of nerve function on krt62.L expression could be seen in the maintenance of krt62.L expression, but not in its induction. When an epidermis-stripped limb bud was grafted in a froglet blastema, the grafted limb bud could reach the digit-forming stage. This suggests that krt62.L-positive froglet blastema epithelium is able to support the limb development process. These findings imply that the developmental process is locally reactivated in an postmetamorphic body during limb regeneration. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  6. De novo transcriptome sequencing of axolotl blastema for identification of differentially expressed genes during limb regeneration

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    2013-01-01

    Background Salamanders are unique among vertebrates in their ability to completely regenerate amputated limbs through the mediation of blastema cells located at the stump ends. This regeneration is nerve-dependent because blastema formation and regeneration does not occur after limb denervation. To obtain the genomic information of blastema tissues, de novo transcriptomes from both blastema tissues and denervated stump ends of Ambystoma mexicanum (axolotls) 14 days post-amputation were sequenced and compared using Solexa DNA sequencing. Results The sequencing done for this study produced 40,688,892 reads that were assembled into 307,345 transcribed sequences. The N50 of transcribed sequence length was 562 bases. A similarity search with known proteins identified 39,200 different genes to be expressed during limb regeneration with a cut-off E-value exceeding 10-5. We annotated assembled sequences by using gene descriptions, gene ontology, and clusters of orthologous group terms. Targeted searches using these annotations showed that the majority of the genes were in the categories of essential metabolic pathways, transcription factors and conserved signaling pathways, and novel candidate genes for regenerative processes. We discovered and confirmed numerous sequences of the candidate genes by using quantitative polymerase chain reaction and in situ hybridization. Conclusion The results of this study demonstrate that de novo transcriptome sequencing allows gene expression analysis in a species lacking genome information and provides the most comprehensive mRNA sequence resources for axolotls. The characterization of the axolotl transcriptome can help elucidate the molecular mechanisms underlying blastema formation during limb regeneration. PMID:23815514

  7. Positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (Ambystoma mexicanum).

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    McCusker, Catherine D; Gardiner, David M

    2013-01-01

    The regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. By grafting cells from different stages and regions of blastemas induced to form on donor animals expressing Green Fluorescent Protein (GFP), to non-GFP host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is reprogrammed by interactions with more proximal cells with stable positional information. In contrast, cells from the adjacent, more proximal stump tissues as well as the basal region of late bud blastemas are positionally stable, and thus form ectopic limb structures when grafted. Finally, we have found that a nerve is required to maintain the blastema cells in a positionally labile state, thus indicating a role for reprogramming cues in the blastema microenvironment.

  8. Positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (Ambystoma mexicanum.

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    Catherine D McCusker

    Full Text Available The regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. By grafting cells from different stages and regions of blastemas induced to form on donor animals expressing Green Fluorescent Protein (GFP, to non-GFP host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is reprogrammed by interactions with more proximal cells with stable positional information. In contrast, cells from the adjacent, more proximal stump tissues as well as the basal region of late bud blastemas are positionally stable, and thus form ectopic limb structures when grafted. Finally, we have found that a nerve is required to maintain the blastema cells in a positionally labile state, thus indicating a role for reprogramming cues in the blastema microenvironment.

  9. Amphibian tail regeneration in space: effect on the pigmentation of the blastema

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    Grinfeld, S.; Foulquier, F.; Mitashov, V.; Bruchlinskaia, N.; Duprat, A. M.

    In Urodele amphibians, the tail regenerates after section. This regeneration, including tissues as different as bone (vertebrae), muscle, epidermis and central nervous system (spinal cord), was studied in adult Pleurodeles sent aboard the russian satellite Bion 10 and compared with tail regeneration in synchronous controls. Spinal cord, muscle and cartilage regeneration occurred in space animals as in synchronous controls. One of the most important differences between the two groups was the pigmentation of the blastemas: it was shown in laboratory, to be not due to a difference in light intensity.

  10. Proteomic analysis of blastema formation in regenerating axolotl limbs

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    Nye Holly LD

    2009-11-01

    Full Text Available Abstract Background Following amputation, urodele salamander limbs reprogram somatic cells to form a blastema that self-organizes into the missing limb parts to restore the structure and function of the limb. To help understand the molecular basis of blastema formation, we used quantitative label-free liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS-based methods to analyze changes in the proteome that occurred 1, 4 and 7 days post amputation (dpa through the mid-tibia/fibula of axolotl hind limbs. Results We identified 309 unique proteins with significant fold change relative to controls (0 dpa, representing 10 biological process categories: (1 signaling, (2 Ca2+ binding and translocation, (3 transcription, (4 translation, (5 cytoskeleton, (6 extracellular matrix (ECM, (7 metabolism, (8 cell protection, (9 degradation, and (10 cell cycle. In all, 43 proteins exhibited exceptionally high fold changes. Of these, the ecotropic viral integrative factor 5 (EVI5, a cell cycle-related oncoprotein that prevents cells from entering the mitotic phase of the cell cycle prematurely, was of special interest because its fold change was exceptionally high throughout blastema formation. Conclusion Our data were consistent with previous studies indicating the importance of inositol triphosphate and Ca2+ signaling in initiating the ECM and cytoskeletal remodeling characteristic of histolysis and cell dedifferentiation. In addition, the data suggested that blastema formation requires several mechanisms to avoid apoptosis, including reduced metabolism, differential regulation of proapoptotic and antiapoptotic proteins, and initiation of an unfolded protein response (UPR. Since there is virtually no mitosis during blastema formation, we propose that high levels of EVI5 function to arrest dedifferentiated cells somewhere in the G1/S/G2 phases of the cell cycle until they have accumulated under the wound epidermis and enter mitosis in response to

  11. Blastema Tissue Formed at Experimentally-Created Rabbit Ear Hole

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    Mohamadreza Baghaban Eslaminejad

    2013-02-01

    Full Text Available   Objective(s: Throughout evolution, mammalians have increasingly lost their ability to regenerate structures however rabbits are exceptional since they develop a blastema in their ear wound for regeneration purposes. Blastema consists of a group of undifferentiated cells capable of dividing and differentiating into the ear tissue. The objective of the present study is to isolate, culture expand, and characterize blastema progenitor cells in terms of their in vitro differentiation capacity.   Materials and Methods: Five New Zealand white male rabbits were used in the present study. Using a punching apparatus, a 4-mm hole was created in the animal ears. Following 4 days, the blastema ring which was created in the periphery of primary hole in the ears was removed and cultivated. The cells migrated from the blastema were expanded through 3 successive subcultures and characterized in terms of their potential differentiation, growth characteristics, and culture requirements. Results: The primary cultures tended to be morphologically heterogeneous having spindly-shaped fibroblast-like cells as well as flattened cells. Fibroblast-like cells survived and dominated the cultures. These cells tended to have the osteogenic, chondrogenic, and adipogenic differentiation potentials. They were highly colonogenic and maximum proliferation was achieved when the cells were plated at density of 100 cells/cm2 in a medium which contained 10% fetal bovine serum (FBS. Conclusion: Taken together, blastema tissue-derived stem cells from rabbit ear are of mesenchymal stem cell-like population. Studies similar to this will assist scientist better understanding the nature of blastema tissue formed at rabbit ear to regenerate the wound.

  12. Misexpression experiment of Tbx5 in axolotl (Ambystoma mexicanum) hindlimb blastema.

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    Shimokawa, Takashi; Kominami, Rieko; Yasutaka, Satoru; Shinohara, Harumichi

    2013-01-01

    Axolotls (Ambystoma mexicanum) have the ability to regenerate amputated limbs throughout their life span. In the present study, we attempted to elucidate how axolotls can specify limb type correctly during the regeneration process. We misexpressed Tbx5 in regenerating hindlimb blastema, and consequently a forelimb-like hindlimb regenerated from the hindlimb blastema. On the other hand, no change was observed in Tbx5-overexpressing forelimb blastema, and thus we considered that Tbx5 plays a key role in the specification of forelimb during the regeneration process of axolotl limbs. However, axolotls' fore- and hindlimbs have very similar structures except for the number of fingers, and it was very difficult to judge whether the forelimb-like regenerate was a true forelimb or merely a forelimb-like hindlimb. Therefore, in order to confirm our conclusion, we have to investigate other genes that are expressed differentially between fore- and hindlimbs in future experiments.

  13. Two msh/msx-related genes, Djmsh1 and Djmsh2, contribute to the early blastema growth during planarian head regeneration.

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    Mannini, Linda; Deri, Paolo; Gremigni, Vittorio; Rossi, Leonardo; Salvetti, Alessandra; Batistoni, Renata

    2008-01-01

    Regeneration in planarians is an intriguing phenomenon, based on the presence of pluripotent stem cells, known as neoblasts. Following amputation, these cells activate mitotic divisions, migrate distally and undergo differentiation, giving rise to the regeneration blastema. We have identified two msh/msx-related genes, Djmsh1 and Djmsh2, which are expressed in distinct cell populations of the planarian Dugesia japonica and activated, with different patterns, during head regeneration. We demonstrate that RNA interference of Djmsh1 or Djmsh2 generates a delay in the growth of cephalic blastema, interfering with the dynamics of mitoses during its initial formation. Our data also reveal that the activity of the two planarian msh genes is required to regulate Djbmp expression during head regeneration. This study identifies, for the first time, a functional association between muscle segment homeobox (MSH) homeoproteins and BMP signaling during stem cell-based regeneration of the planarian head and provides a functional analysis of how msh genes may regulate in vivo the regenerative response of planarian stem cells.

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

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    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

  15. Unique gene expression profile of the proliferating Xenopus tadpole tail blastema cells deciphered by RNA-sequencing analysis.

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    Hiroshi Tsujioka

    Full Text Available Organ regenerative ability depends on the animal species and the developmental stage. The molecular bases for variable organ regenerative ability, however, remain unknown. Previous studies have identified genes preferentially expressed in the blastema tissues in various animals, but transcriptome analysis of the isolated proliferating blastema cells has not yet been reported. In the present study, we used RNA-sequencing analysis to analyze the gene expression profile of isolated proliferating blastema cells of regenerating Xenopus laevis tadpole tails. We used flow cytometry to isolate proliferating cells, and non-proliferating blastema cells, from regenerating tadpole tails as well as proliferating tail bud cells from tail bud embryos, the latter two of which were used as control cells, based on their DNA content. Among the 28 candidate genes identified by RNA-sequencing analysis, quantitative reverse transcription-polymerase chain reaction identified 10 genes whose expression was enriched in regenerating tadpole tails compared with non-regenerating tadpole tails or tails from the tail bud embryos. Among them, whole mount in situ hybridization revealed that chromosome segregation 1-like and interleukin 11 were expressed in the broad area of the tail blastema, while brevican, lysyl oxidase, and keratin 18 were mainly expressed in the notochord bud in regenerating tails. We further combined whole mount in situ hybridization with immunohistochemistry for the incorporated 5-bromo-2-deoxyuridine to confirm that keratin 18 and interleukin 11 were expressed in the proliferating tail blastema cells. Based on the proposed functions of their homologs in other animal species, these genes might have roles in the extracellular matrix formation in the notochord bud (brevican and lysyl oxidase, cell proliferation (chromosome segregation 1-like and keratin 18, and in the maintenance of the differentiation ability of proliferating blastema cells (interleukin 11

  16. Isolation and Characterization of the Progenitor Cells From the Blastema Tissue Formed at Experimentally-Created Rabbit Ear Hole

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    Baghaban Eslaminejad, Mohamadreza; Bordbar, Sima

    2013-01-01

      Objective(s): Throughout evolution, mammalians have increasingly lost their ability to regenerate structures however rabbits are exceptional since they develop a blastema in their ear wound for regeneration purposes. Blastema consists of a group of undifferentiated cells capable of dividing and differentiating into the ear tissue. The objective of the present study is to isolate, culture expand, and characterize blastema progenitor cells in terms of their in vitro differentiation capacity. ...

  17. Isolation and characterization of the progenitor cells from the blastema tissue formed at experimentally-created rabbit ear hole.

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    Baghaban Eslaminejad, Mohamadreza; Bordbar, Sima

    2013-02-01

    Objective(s) : Throughout evolution, mammalians have increasingly lost their ability to regenerate structures however rabbits are exceptional since they develop a blastema in their ear wound for regeneration purposes. Blastema consists of a group of undifferentiated cells capable of dividing and differentiating into the ear tissue. The objective of the present study is to isolate, culture expand, and characterize blastema progenitor cells in terms of their in vitro differentiation capacity. Five New Zealand white male rabbits were used in the present study. Using a punching apparatus, a 4-mm hole was created in the animal ears. Following 4 days, the blastema ring which was created in the periphery of primary hole in the ears was removed and cultivated. The cells migrated from the blastema were expanded through 3 successive subcultures and characterized in terms of their potential differentiation, growth characteristics, and culture requirements. The primary cultures tended to be morphologically heterogeneous having spindly-shaped fibroblast-like cells as well as flattened cells. Fibroblast-like cells survived and dominated the cultures. These cells tended to have the osteogenic, chondrogenic, and adipogenic differentiation potentials. They were highly colonogenic and maximum proliferation was achieved when the cells were plated at density of 100 cells/cm2 in a medium which contained 10% fetal bovine serum (FBS). Taken together, blastema tissue-derived stem cells from rabbit ear are of mesenchymal stem cell-like population. Studies similar to this will assist scientist better understanding the nature of blastema tissue formed at rabbit ear to regenerate the wound.

  18. Msh homeobox 1 (Msx1)- and Msx2-overexpressing bone marrow-derived mesenchymal stem cells resemble blastema cells and enhance regeneration in mice.

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    Taghiyar, Leila; Hesaraki, Mahdi; Sayahpour, Forough Azam; Satarian, Leila; Hosseini, Samaneh; Aghdami, Naser; Baghaban Eslaminejad, Mohamadreza

    2017-06-23

    Amputation of the proximal region in mammals is not followed by regeneration because blastema cells (BCs) and expression of regenerative genes, such as Msh homeobox ( Msx ) genes, are absent in this animal group. The lack of BCs and positional information in other cells is therefore the main obstacle to therapeutic approaches for limb regeneration. Hence, this study aimed to create blastema-like cells (BlCs) by overexpressing Msx1 and Msx2 genes in mouse bone marrow-derived mesenchymal stem cells (mBMSCs) to regenerate a proximally amputated digit tip. We transduced mBMSCs with Msx1 and Msx2 genes and compared osteogenic activity and expression levels of several Msx -regulated genes ( Bmp4 , Fgf8 , and keratin 14 ( K14 )) in BlC groups, including MSX1, MSX2, and MSX1/2 (in a 1:1 ratio) with those in mBMSCs and BCs in vitro and in vivo following injection into the amputation site. We found that Msx gene overexpression increased expression of specific blastemal markers and enhanced the proliferation rate and osteogenesis of BlCs compared with mBMSCs and BCs via activation of Fgf8 and Bmp4 Histological analyses indicated full regrowth of digit tips in the Msx -overexpressing groups, particularly in MSX1/2, through endochondral ossification 6 weeks post-injection. In contrast, mBMSCs and BCs formed abnormal bone and nail. Full digit tip was regenerated only in the MSX1/2 group and was related to boosted Bmp4, Fgf8 , and K14 gene expression and to limb-patterning properties resulting from Msx1 and Msx2 overexpression. We propose that Msx -transduced cells that can regenerate epithelial and mesenchymal tissues may potentially be utilized in limb regeneration. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Regulation of Axolotl (Ambystoma mexicanum) Limb Blastema Cell Proliferation by Nerves and BMP2 in Organotypic Slice Culture.

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    Lehrberg, Jeffrey; Gardiner, David M

    2015-01-01

    We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response.

  20. Regulation of Axolotl (Ambystoma mexicanum Limb Blastema Cell Proliferation by Nerves and BMP2 in Organotypic Slice Culture.

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    Jeffrey Lehrberg

    Full Text Available We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response.

  1. Angiogenesis is inhibitory for mammalian digit regeneration

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    Yu, Ling; Yan, Mingquan; Simkin, Jennifer; Ketcham, Paulina D.; Leininger, Eric; Han, Manjong

    2014-01-01

    Abstract The regenerating mouse digit tip is a unique model for investigating blastema formation and epimorphic regeneration in mammals. The blastema is characteristically avascular and we previously reported that blastema expression of a known anti‐angiogenic factor gene, Pedf, correlated with a successful regenerative response (Yu, L., Han, M., Yan, M., Lee, E. C., Lee, J. & Muneoka, K. (2010). BMP signaling induces digit regeneration in neonatal mice. Development, 137, 551–559). Here we show that during regeneration Vegfa transcripts are not detected in the blastema but are expressed at the onset of differentiation. Treating the amputation wound with vascular endothelial growth factor enhances angiogenesis but inhibits regeneration. We next tested bone morphogenetic protein 9 (BMP9), another known mediator of angiogenesis, and found that BMP9 is also a potent inhibitor of digit tip regeneration. BMP9 induces Vegfa expression in the digit stump suggesting that regenerative failure is mediated by enhanced angiogenesis. Finally, we show that BMP9 inhibition of regeneration is completely rescued by treatment with pigment epithelium‐derived factor. These studies show that precocious angiogenesis is inhibitory for regeneration, and provide compelling evidence that the regulation of angiogenesis is a critical factor in designing therapies aimed at stimulating mammalian regeneration. PMID:27499862

  2. Neuregulin-1 signaling is essential for nerve-dependent axolotl limb regeneration.

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    Farkas, Johanna E; Freitas, Polina D; Bryant, Donald M; Whited, Jessica L; Monaghan, James R

    2016-08-01

    The Mexican axolotl (Ambystoma mexicanum) is capable of fully regenerating amputated limbs, but denervation of the limb inhibits the formation of the post-injury proliferative mass called the blastema. The molecular basis behind this phenomenon remains poorly understood, but previous studies have suggested that nerves support regeneration via the secretion of essential growth-promoting factors. An essential nerve-derived factor must be found in the blastema, capable of rescuing regeneration in denervated limbs, and its inhibition must prevent regeneration. Here, we show that the neuronally secreted protein Neuregulin-1 (NRG1) fulfills all these criteria in the axolotl. Immunohistochemistry and in situ hybridization of NRG1 and its active receptor ErbB2 revealed that they are expressed in regenerating blastemas but lost upon denervation. NRG1 was localized to the wound epithelium prior to blastema formation and was later strongly expressed in proliferating blastemal cells. Supplementation by implantation of NRG1-soaked beads rescued regeneration to digits in denervated limbs, and pharmacological inhibition of NRG1 signaling reduced cell proliferation, blocked blastema formation and induced aberrant collagen deposition in fully innervated limbs. Taken together, our results show that nerve-dependent NRG1/ErbB2 signaling promotes blastemal proliferation in the regenerating limb and may play an essential role in blastema formation, thus providing insight into the longstanding question of why nerves are required for axolotl limb regeneration. © 2016. Published by The Company of Biologists Ltd.

  3. Blastema from rabbit ear contains progenitor cells comparable to marrow derived mesenchymal stem cells

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    Mohamadreza Baghaban Eslaminejad

    2012-09-01

    Full Text Available Rabbits have the capacity to regenerate holes in their ears by forming a blastema, a tissue that is made up of a group of undifferentiated cells. The purpose of the present study was to isolate and characterize blastema progenitor cells and compare them with marrow mesenchymal stem cells (MSCs. Five New Zealand white male rabbits were used in the present study. A 2-mm hole was created in the animal ears. After 4 days, the blastema ring formed in the periphery of the hole was removed and cultivated. The cells were expanded through several subcultures and compared with the MSCs derived from the marrow of same animal in terms of in vitro differentiation capacity, growth kinetics and culture requirements for optimal proliferation. The primary cultures from both cells tended to be heterogeneous. Fibroblastic cells became progressively dominant with advancing passages. Similar to MSCs blastema passaged-3 cells succeeded to differentiate into bone, cartilage and adipose cell lineages. Even lineage specific genes tended to express in higher level in blastema cells compared to MSCs (p < 0.05. Moreover blastema cells appeared more proliferative; producing more colonies (p < 0.05. While blastema cells showed extensive proliferation in 15% fetal bovine serum (FBS, MSCs displayed higher expansion rate at 10% FBS. In conclusion, blastema from rabbit ear contains a population of fibroblastic cells much similar in characteristic to bone marrow mesenchymal stem cells. However, the two cells were different in the level of lineage-specific gene expression, the growth curve characteristics and the culture requirements.

  4. Comparative RNA-seq analysis in the unsequenced axolotl: the oncogene burst highlights early gene expression in the blastema.

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    Ron Stewart

    Full Text Available The salamander has the remarkable ability to regenerate its limb after amputation. Cells at the site of amputation form a blastema and then proliferate and differentiate to regrow the limb. To better understand this process, we performed deep RNA sequencing of the blastema over a time course in the axolotl, a species whose genome has not been sequenced. Using a novel comparative approach to analyzing RNA-seq data, we characterized the transcriptional dynamics of the regenerating axolotl limb with respect to the human gene set. This approach involved de novo assembly of axolotl transcripts, RNA-seq transcript quantification without a reference genome, and transformation of abundances from axolotl contigs to human genes. We found a prominent burst in oncogene expression during the first day and blastemal/limb bud genes peaking at 7 to 14 days. In addition, we found that limb patterning genes, SALL genes, and genes involved in angiogenesis, wound healing, defense/immunity, and bone development are enriched during blastema formation and development. Finally, we identified a category of genes with no prior literature support for limb regeneration that are candidates for further evaluation based on their expression pattern during the regenerative process.

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

    Science.gov (United States)

    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

  6. Early regulation of axolotl limb regeneration.

    Science.gov (United States)

    Makanae, Aki; Satoh, Akira

    2012-10-01

    Amphibian limb regeneration has been studied for a long time. In amphibian limb regeneration, an undifferentiated blastema is formed around the region damaged by amputation. The induction process of blastema formation has remained largely unknown because it is difficult to study the induction of limb regeneration. The recently developed accessory limb model (ALM) allows the investigation of limb induction and reveals early events of amphibian limb regeneration. The interaction between nerves and wound epidermis/epithelium is an important aspect of limb regeneration. During early limb regeneration, neurotrophic factors act on wound epithelium, leading to development of a functional epidermis/epithelium called the apical epithelial cap (AEC). AEC and nerves create a specific environment that inhibits wound healing and induces regeneration through blastema formation. It is suggested that FGF-signaling and MMP activities participate in creating a regenerative environment. To understand why urodele amphibians can create such a regenerative environment and humans cannot, it is necessary to identify the similarities and differences between regenerative and nonregenerative animals. Here we focus on ALM to consider limb regeneration from a new perspective and we also reported that focal adhesion kinase (FAK)-Src signaling controlled fibroblasts migration in axolotl limb regeneration. Copyright © 2012 Wiley Periodicals, Inc.

  7. Comparative Analysis of Cartilage Marker Gene Expression Patterns during Axolotl and Xenopus Limb Regeneration.

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    Kazumasa Mitogawa

    Full Text Available Axolotls (Ambystoma mexicanum can completely regenerate lost limbs, whereas Xenopus laevis frogs cannot. During limb regeneration, a blastema is first formed at the amputation plane. It is thought that this regeneration blastema forms a limb by mechanisms similar to those of a developing embryonic limb bud. Furthermore, Xenopus laevis frogs can form a blastema after amputation; however, the blastema results in a terminal cone-shaped cartilaginous structure called a "spike." The causes of this patterning defect in Xenopus frog limb regeneration were explored. We hypothesized that differences in chondrogenesis may underlie the patterning defect. Thus, we focused on chondrogenesis. Chondrogenesis marker genes, type I and type II collagen, were compared in regenerative and nonregenerative environments. There were marked differences between axolotls and Xenopus in the expression pattern of these chondrogenesis-associated genes. The relative deficit in the chondrogenic capacity of Xenopus blastema cells may account for the absence of total limb regenerative capacity.

  8. Hyperinnervation improves Xenopus laevis limb regeneration.

    Science.gov (United States)

    Mitogawa, Kazumasa; Makanae, Aki; Satoh, Akira

    2018-01-15

    Xenopus laevis (an anuran amphibian) shows limb regeneration ability between that of urodele amphibians and that of amniotes. Xenopus frogs can initiate limb regeneration but fail to form patterned limbs. Regenerated limbs mainly consist of cone-shaped cartilage without any joints or branches. These pattern defects are thought to be caused by loss of proper expressions of patterning-related genes. This study shows that hyperinnervation surgery resulted in the induction of a branching regenerate. The hyperinnervated blastema allows the identification and functional analysis of the molecules controlling this patterning of limb regeneration. This paper focuses on the nerve affects to improve Xenopus limb patterning ability during regeneration. The nerve molecules, which regulate limb patterning, were also investigated. Blastemas grown in a hyperinnervated forelimb upregulate limb patterning-related genes (shh, lmx1b, and hoxa13). Nerves projecting their axons to limbs express some growth factors (bmp7, fgf2, fgf8, and shh). Inputs of these factors to a blastema upregulated some limb patterning-related genes and resulted in changes in the cartilage patterns in the regenerates. These results indicate that additional nerve factors enhance Xenopus limb patterning-related gene expressions and limb regeneration ability, and that bmp, fgf, and shh are candidate nerve substitute factors. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Macrophages are required to coordinate mouse digit tip regeneration.

    Science.gov (United States)

    Simkin, Jennifer; Sammarco, Mimi C; Marrero, Luis; Dawson, Lindsay A; Yan, Mingquan; Tucker, Catherine; Cammack, Alex; Muneoka, Ken

    2017-11-01

    In mammals, macrophages are known to play a major role in tissue regeneration. They contribute to inflammation, histolysis, re-epithelialization, revascularization and cell proliferation. Macrophages have been shown to be essential for regeneration in salamanders and fish, but their role has not been elucidated in mammalian epimorphic regeneration. Here, using the regenerating mouse digit tip as a mammalian model, we demonstrate that macrophages are essential for the regeneration process. Using cell-depletion strategies, we show that regeneration is completely inhibited; bone histolysis does not occur, wound re-epithelialization is inhibited and the blastema does not form. Although rescue of epidermal wound closure in the absence of macrophages promotes blastema accumulation, it does not rescue cell differentiation, indicating that macrophages play a key role in the redifferentiation of the blastema. We provide additional evidence that although bone degradation is a component, it is not essential to the overall regenerative process. These findings show that macrophages play an essential role in coordinating the epimorphic regenerative response in mammals. © 2017. Published by The Company of Biologists Ltd.

  10. Live Imaging of Axolotl Digit Regeneration Reveals Spatiotemporal Choreography of Diverse Connective Tissue Progenitor Pools.

    Science.gov (United States)

    Currie, Joshua D; Kawaguchi, Akane; Traspas, Ricardo Moreno; Schuez, Maritta; Chara, Osvaldo; Tanaka, Elly M

    2016-11-21

    Connective tissues-skeleton, dermis, pericytes, fascia-are a key cell source for regenerating the patterned skeleton during axolotl appendage regeneration. This complexity has made it difficult to identify the cells that regenerate skeletal tissue. Inability to identify these cells has impeded a mechanistic understanding of blastema formation. By tracing cells during digit tip regeneration using brainbow transgenic axolotls, we show that cells from each connective tissue compartment have distinct spatial and temporal profiles of proliferation, migration, and differentiation. Chondrocytes proliferate but do not migrate into the regenerate. In contrast, pericytes proliferate, then migrate into the blastema and give rise solely to pericytes. Periskeletal cells and fibroblasts contribute the bulk of digit blastema cells and acquire diverse fates according to successive waves of migration that choreograph their proximal-distal and tissue contributions. We further show that platelet-derived growth factor signaling is a potent inducer of fibroblast migration, which is required to form the blastema. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Network based transcription factor analysis of regenerating axolotl limbs

    Directory of Open Access Journals (Sweden)

    Cameron Jo Ann

    2011-03-01

    Full Text Available Abstract Background Studies on amphibian limb regeneration began in the early 1700's but we still do not completely understand the cellular and molecular events of this unique process. Understanding a complex biological process such as limb regeneration is more complicated than the knowledge of the individual genes or proteins involved. Here we followed a systems biology approach in an effort to construct the networks and pathways of protein interactions involved in formation of the accumulation blastema in regenerating axolotl limbs. Results We used the human orthologs of proteins previously identified by our research team as bait to identify the transcription factor (TF pathways and networks that regulate blastema formation in amputated axolotl limbs. The five most connected factors, c-Myc, SP1, HNF4A, ESR1 and p53 regulate ~50% of the proteins in our data. Among these, c-Myc and SP1 regulate 36.2% of the proteins. c-Myc was the most highly connected TF (71 targets. Network analysis showed that TGF-β1 and fibronectin (FN lead to the activation of these TFs. We found that other TFs known to be involved in epigenetic reprogramming, such as Klf4, Oct4, and Lin28 are also connected to c-Myc and SP1. Conclusions Our study provides a systems biology approach to how different molecular entities inter-connect with each other during the formation of an accumulation blastema in regenerating axolotl limbs. This approach provides an in silico methodology to identify proteins that are not detected by experimental methods such as proteomics but are potentially important to blastema formation. We found that the TFs, c-Myc and SP1 and their target genes could potentially play a central role in limb regeneration. Systems biology has the potential to map out numerous other pathways that are crucial to blastema formation in regeneration-competent limbs, to compare these to the pathways that characterize regeneration-deficient limbs and finally, to identify stem

  12. Expression of Msx genes in regenerating and developing limbs of axolotl.

    Science.gov (United States)

    Koshiba, K; Kuroiwa, A; Yamamoto, H; Tamura, K; Ide, H

    1998-12-15

    Msx genes, homeobox-containing genes, have been isolated as homologues of the Drosophila msh gene and are thought to play important roles in the development of chick or mouse limb buds. We isolated two Msx genes, Msx1 and Msx2, from regenerating blastemas of axolotl limbs and examined their expression patterns using Northern blot and whole mount in situ hybridization during regeneration and development. Northern blot analysis revealed that the expression level of both Msx genes increased during limb regeneration. The Msx2 expression level increased in the blastema at the early bud stage, and Msx1 expression level increased at the late bud stage. Whole mount in situ hybridization revealed that Msx2 was expressed in the distal mesenchyme and Msx1 in the entire mesenchyme of the blastema at the late bud stage. In the developing limb bud, Msx1 was expressed in the entire mesenchyme, while Msx2 was expressed in the distal and peripheral mesenchyme. The expression patterns of Msx genes in the blastemas and limb buds of the axolotl were different from those reported for chick or mouse limb buds. These expression patterns of axolotl Msx genes are discussed in relation to the blastema or limb bud morphology and their possible roles in limb patterning.

  13. Gecko CD59 Is Implicated in Proximodistal Identity during Tail Regeneration

    Science.gov (United States)

    Jiang, Shengjuan; Zhou, Weijuan; Liu, Yan; Wang, Yingjie; Gu, Qing; Gu, Yun; Dong, Yingying; Liu, Mei; Gu, Xingxing; Ding, Fei; Gu, Xiaosong

    2011-01-01

    Several adult reptiles, such as Gekko japonicus, have the ability to precisely re-create a missing tail after amputation. To ascertain the associated acquisition of positional information from blastemal cells and the underlying molecular mechanism of tail regeneration, a candidate molecule CD59 was isolated from gecko. CD59 transcripts displayed a graded expression in the adult gecko spinal cord with the highest level in the anterior segment, with a stable expression along the normal tail. After tail amputation, CD59 transcripts in the spinal cord proximal to the injury sites increased markedly at 1 day and 2 weeks; whereas in the regenerating blastema, strong CD59 positive signals were detected in the blastemal cells anterior to the blastema, with a gradual decrease along the proximodistal (PD) axis. When treated with RA following amputation, CD59 transcripts in the blastema were up-regulated. PD confrontation assays revealed that the proximal blastema engulfed the distal one after in vitro culture, and rabbit-anti human CD59 antibody was able to block this PD engulfment. Overexpression of the CD59 during tail regeneration causes distal blastemal cells to translocate to a more proximal location. Our results suggest that position identity is not restricted to amphibian limb regeneration, but has already been established in tail blastema of reptiles. The CD59, a cell surface molecule, acted as a determinant of proximal–distal cell identity. PMID:21464923

  14. An Ambystoma mexicanum EST sequencing project: analysis of 17,352 expressed sequence tags from embryonic and regenerating blastema cDNA libraries

    Science.gov (United States)

    Habermann, Bianca; Bebin, Anne-Gaelle; Herklotz, Stephan; Volkmer, Michael; Eckelt, Kay; Pehlke, Kerstin; Epperlein, Hans Henning; Schackert, Hans Konrad; Wiebe, Glenis; Tanaka, Elly M

    2004-01-01

    Background The ambystomatid salamander, Ambystoma mexicanum (axolotl), is an important model organism in evolutionary and regeneration research but relatively little sequence information has so far been available. This is a major limitation for molecular studies on caudate development, regeneration and evolution. To address this lack of sequence information we have generated an expressed sequence tag (EST) database for A. mexicanum. Results Two cDNA libraries, one made from stage 18-22 embryos and the other from day-6 regenerating tail blastemas, generated 17,352 sequences. From the sequenced ESTs, 6,377 contigs were assembled that probably represent 25% of the expressed genes in this organism. Sequence comparison revealed significant homology to entries in the NCBI non-redundant database. Further examination of this gene set revealed the presence of genes involved in important cell and developmental processes, including cell proliferation, cell differentiation and cell-cell communication. On the basis of these data, we have performed phylogenetic analysis of key cell-cycle regulators. Interestingly, while cell-cycle proteins such as the cyclin B family display expected evolutionary relationships, the cyclin-dependent kinase inhibitor 1 gene family shows an unusual evolutionary behavior among the amphibians. Conclusions Our analysis reveals the importance of a comprehensive sequence set from a representative of the Caudata and illustrates that the EST sequence database is a rich source of molecular, developmental and regeneration studies. To aid in data mining, the ESTs have been organized into an easily searchable database that is freely available online. PMID:15345051

  15. A novel amniote model of epimorphic regeneration: the leopard gecko, Eublepharis macularius.

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    McLean, Katherine E; Vickaryous, Matthew K

    2011-08-16

    Epimorphic regeneration results in the restoration of lost tissues and structures from an aggregation of proliferating cells known as a blastema. Among amniotes the most striking example of epimorphic regeneration comes from tail regenerating lizards. Although tail regeneration is often studied in the context of ecological costs and benefits, details of the sequence of tissue-level events are lacking. Here we investigate the anatomical and histological events that characterize tail regeneration in the leopard gecko, Eublepharis macularius. Tail structure and tissue composition were examined at multiple days following tail loss, revealing a conserved pattern of regeneration. Removal of the tail results in a consistent series of morphological and histological events. Tail loss is followed by a latent period of wound healing with no visible signs of regenerative outgrowth. During this latent period basal cells of the epidermis proliferate and gradually cover the wound. An additional aggregation of proliferating cells accumulates adjacent to the distal tip of the severed spinal cord marking the first appearance of the blastema. Continued growth of the blastema is matched by the initiation of angiogenesis, followed by the re-development of peripheral axons and the ependymal tube of the spinal cord. Skeletal tissue differentiation, corresponding with the expression of Sox9, and muscle re-development are delayed until tail outgrowth is well underway. We demonstrate that tail regeneration in lizards involves a highly conserved sequence of events permitting the establishment of a staging table. We show that tail loss is followed by a latent period of scar-free healing of the wound site, and that regeneration is blastema-mediated. We conclude that the major events of epimorphic regeneration are highly conserved across vertebrates and that a comparative approach is an invaluable biomedical tool for ongoing regenerative research.

  16. Gene expression patterns specific to the regenerating limb of the Mexican axolotl

    Directory of Open Access Journals (Sweden)

    James R. Monaghan

    2012-07-01

    Salamander limb regeneration is dependent upon tissue interactions that are local to the amputation site. Communication among limb epidermis, peripheral nerves, and mesenchyme coordinate cell migration, cell proliferation, and tissue patterning to generate a blastema, which will form missing limb structures. An outstanding question is how cross-talk between these tissues gives rise to the regeneration blastema. To identify genes associated with epidermis-nerve-mesenchymal interactions during limb regeneration, we examined histological and transcriptional changes during the first week following injury in the wound epidermis and subjacent cells between three injury types; 1 a flank wound on the side of the animal that will not regenerate a limb, 2 a denervated limb that will not regenerate a limb, and 3 an innervated limb that will regenerate a limb. Early, histological and transcriptional changes were similar between the injury types, presumably because a common wound-healing program is employed across anatomical locations. However, some transcripts were enriched in limbs compared to the flank and are associated with vertebrate limb development. Many of these genes were activated before blastema outgrowth and expressed in specific tissue types including the epidermis, peripheral nerve, and mesenchyme. We also identified a relatively small group of transcripts that were more highly expressed in innervated limbs versus denervated limbs. These transcripts encode for proteins involved in myelination of peripheral nerves, epidermal cell function, and proliferation of mesenchymal cells. Overall, our study identifies limb-specific and nerve-dependent genes that are upstream of regenerative growth, and thus promising candidates for the regulation of blastema formation.

  17. Analysis of the expression and function of Wnt-5a and Wnt-5b in developing and regenerating axolotl (Ambystoma mexicanum) limbs.

    Science.gov (United States)

    Ghosh, Sukla; Roy, Stéphane; Séguin, Carl; Bryant, Susan V; Gardiner, David M

    2008-05-01

    Urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. Studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. Progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morphogenesis, growth and pattern formation. Members of the Wnt family of secreted proteins are expressed in developing and regenerating limbs, and have the potential to control growth, pattern formation and differentiation. We have studied the expression of two non-canonical Wnt genes, Wnt-5a and Wnt-5b. We report that they are expressed in equivalent patterns during limb development and limb regeneration in the axolotl (Ambystoma mexicanum), and during limb development in other tetrapods, implying conservation of function. Our analysis of the effects of ectopic Wnt-5a expression is consistent with the hypothesis that canonical Wnt signaling functions during the early stages of regeneration to control the dedifferentiation of stump cells giving rise to the regeneration-competent cells of the blastema.

  18. The role of irradiated tissue during pattern formation in the regenerating limb

    International Nuclear Information System (INIS)

    Maden, M.

    1979-01-01

    The amphibian limb regeneration blastema is used here to examine whether irradiated, non-dividing tissue can participate in the development of new patterns of morphogenesis. Irradiated blastemas were rotated 180 0 on normal stumps and normal blastemas rotated on irradiated stumps. In both cases supernumerary elements developed from the unirradiated tissue. The supernumeraries were defective but this did not seem to be due to a lack of tissue. Rather it suggested that this could be a realization of compartments in vertebrate development or simply reflect the limited regulative ability of the blastema. The results are also discussed in relation to a recent model of pattern formation. (author)

  19. Hyaluronic acid in the tail and limb of amphibians and lizards recreates permissive embryonic conditions for regeneration due to its hygroscopic and immunosuppressive properties.

    Science.gov (United States)

    Alibardi, Lorenzo

    2017-12-01

    The present review focuses on the role of hyaluronate (hyaluronic acid; HA) during limb and tail regeneration in amphibians and lizards mainly in relation to cells of the immune system. This non-sulfated glycosaminoglycan (GAG) increases in early stages of wound healing and blastema formation, like during limb or tail embryogenesis, when the immune system is still immature. The formation of a regenerating blastema occurs by the accumulation of mesenchymal cells displaying embryonic-like antigens and HA. This GAG adsorbs large amount of water and generates a soft tissue over 80% hydrated where mesenchymal and epithelial cells can move and interact, an obligatory passage for organ regeneration. GAGs and HA in particular rise to a high amount and coat plasma membranes of blastema cells forming a shield that likely impedes to the circulating immune cells to elicit an immune reaction against the embryonic-like antigens present on blastema cells. The evolution of limb-tail regeneration in amphibians dates back to the Devonian-Carboniferous, while tail regeneration in lizards is a more recent evolution process, possibly occurred since the Jurassic, which is unique among amniotes. Both processes are associated with the reactivation of proliferating embryonic programs that involve the upregulation of genes for Wnt, non-coding RNAs, and HA synthesis in an immune-suppress organ, the regenerative blastema. Failure of maintaining a lasting HA synthesis for the formation of a highly hydrated blastema leads to scarring, the common healing process of amniotes equipped with an efficient immune system. The study of amphibian and lizard regeneration indicates that attempts to stimulate organ regeneration in other vertebrates require the induction of a highly hydrated and immune-depressed, HA-rich environment, similar to the extracellular environment present during development. © 2017 Wiley Periodicals, Inc.

  20. Differential induction of four msx homeobox genes during fin development and regeneration in zebrafish.

    Science.gov (United States)

    Akimenko, M A; Johnson, S L; Westerfield, M; Ekker, M

    1995-02-01

    To study the genetic regulation of growth control and pattern formation during fin development and regeneration, we have analysed the expression of four homeobox genes, msxA, msxB, msxC and msxD in zebrafish fins. The median fin fold, which gives rise to the unpaired fins, expresses these four msx genes during development. Transcripts of the genes are also present in cells of the presumptive pectoral fin buds. The most distal cells, the apical ectodermal ridge of the paired fins and the cleft and flanking cells of the median fin fold express all these msx genes with the exception of msxC. Mesenchymal cells underlying the most distal cells express all four genes. Expression of the msx genes in the fin fold and fin buds is transient and, by 3 days after fertilization, msx expression in the median fin fold falls below levels detectable by in situ hybridization. Although the fins of adult zebrafish normally have levels of msx transcripts undetectable by in situ hybridization, expression of all four genes is strongly reinduced during regeneration of both paired and unpaired fins. Induction of msx gene expression in regenerating caudal fins occurs as early as 30 hours postamputation. As the blastema forms, the levels of expression increase and reach a maximum between the third and fifth days. Then, msx expression progressively declines and disappears by day 12 when the caudal fin has grown back to its normal size. In the regenerating fin, the blastema cells that develop at the tip of each fin ray express msxB and msxC. Cells of the overlying epithelium express msxA and msxD, but do not express msxB or msxC. Amputations at various levels along the proximodistal axis of the fin suggest that msxB expression depends upon the position of the blastema, with cells of the rapidly proliferating proximal blastema expressing higher levels than the cells of the less rapidly proliferating distal blastema. Expression of msxC and msxD is independent of the position of the blastema cell

  1. Mechanisms mediating the trophic effect of nerves during vertebrate limb regeneration

    International Nuclear Information System (INIS)

    Munaim, S.I.

    1986-01-01

    Salamanders regenerate their appendages after amputation and nerves are required for this process. Experiments were designed to test the idea that one way nerves could affect blastema cell proliferation is by influencing the metabolism of extracellular matrix (ECM) components and to identify neurotrophic factors which promote blastema cell mitosis. Temporal and spatial differences of glycosaminoglycans (GAGs) synthesis is innervated and denervated limbs were examined. Hyaluronic acid (HA) was found to be the major GAG produced during the proliferative period and chondroitin sulfate during differentiation. Denervation reduced synthesis of both these components by half. Dorsal root ganglia and fibroblast growth factor (FGF), a brain-derived mitogen, similarly doubled GAG synthesis in cultured blastemas, the FGF-effect being primarily on HA production. Histochemical and autoradiographical results confirmed the biochemical data. Autoradiography of the limb tissue showed heaviest labeling of the ECM with 3 H-acetate in areas which also stained most intensely with the dye, carbocyanine DBTC. Denervation reduced the staining and the radioactive labeling. These data indicate that nerves affect synthesis and accumulation of GAGs in the regenerating limb, which may be one way blastema cell proliferation is promoted

  2. Comparative transcriptional profiling of the axolotl limb identifies a tripartite regeneration-specific gene program.

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    Dunja Knapp

    Full Text Available Understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. Here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. This comparison between wound healing and regeneration allowed us to identify amputation-specific genes. By clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression - early wound healing followed by a transition-phase leading to establishment of the limb development program, which correspond to the three phases of limb regeneration that had been defined by morphological criteria. By focusing on the transition-phase, we identified 93 strictly amputation-associated genes many of which are implicated in oxidative-stress response, chromatin modification, epithelial development or limb development. We further classified the genes based on whether they were or were not significantly expressed in the developing limb bud. The specific localization of 53 selected candidates within the blastema was investigated by in situ hybridization. In summary, we identified a set of genes that are expressed specifically during regeneration and are therefore, likely candidates for the regulation of blastema formation.

  3. Live fate-mapping of joint-associated fibroblasts visualizes expansion of cell contributions during zebrafish fin regeneration.

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    Tornini, Valerie A; Thompson, John D; Allen, Raymond L; Poss, Kenneth D

    2017-08-15

    The blastema is a mass of progenitor cells responsible for regeneration of amputated salamander limbs and fish fins. Previous studies have indicated that resident cell sources producing the blastema contribute lineage-restricted progeny to regenerating tissue. However, these studies have labeled general cell types rather than granular cell subpopulations, and they do not explain the developmental transitions that must occur for distal structures to arise from cells with proximal identities in the appendage stump. Here, we find that regulatory sequences of tph1b , which encodes an enzyme that synthesizes serotonin, mark a subpopulation of fibroblast-like cells restricted to the joints of uninjured adult zebrafish fins. Amputation stimulates serotonin production in regenerating fin fibroblasts, yet targeted tph1b mutations abrogating this response do not disrupt fin regeneration. In uninjured animals, tph1b -expressing cells contribute fibroblast progeny that remain restricted to joints throughout life. By contrast, upon amputation, tph1b + joint cells give rise to fibroblasts that distribute across the entire lengths of regenerating fin rays. Our experiments visualize and quantify how incorporation into an appendage blastema broadens the progeny contributions of a cellular subpopulation that normally has proximodistal restrictions. © 2017. Published by The Company of Biologists Ltd.

  4. Comparative analysis of ear-hole closure identifies epimorphic regeneration as a discrete trait in mammals

    Science.gov (United States)

    Gawriluk, Thomas R.; Simkin, Jennifer; Thompson, Katherine L.; Biswas, Shishir K.; Clare-Salzler, Zak; Kimani, John M.; Kiama, Stephen G.; Smith, Jeramiah J.; Ezenwa, Vanessa O.; Seifert, Ashley W.

    2016-01-01

    Why mammals have poor regenerative ability has remained a long-standing question in biology. In regenerating vertebrates, injury can induce a process known as epimorphic regeneration to replace damaged structures. Using a 4-mm ear punch assay across multiple mammalian species, here we show that several Acomys spp. (spiny mice) and Oryctolagus cuniculus completely regenerate tissue, whereas other rodents including MRL/MpJ ‘healer' mice heal similar injuries by scarring. We demonstrate ear-hole closure is independent of ear size, and closure rate can be modelled with a cubic function. Cellular and genetic analyses reveal that injury induces blastema formation in Acomys cahirinus. Despite cell cycle re-entry in Mus musculus and A. cahirinus, efficient cell cycle progression and proliferation only occurs in spiny mice. Together, our data unite blastema-mediated regeneration in spiny mice with regeneration in other vertebrates such as salamanders, newts and zebrafish, where all healthy adults regenerate in response to injury. PMID:27109826

  5. Development of a Novel Tissue Engineering Strategy Towards Whole Limb Regeneration

    National Research Council Canada - National Science Library

    Laurencin, Cato T

    2008-01-01

    .... In contrast to the bottom up approach of limb regeneration that relies on blastema formation outgrowth and cell dedifferentiation as seen in amphibians and lower vertebrates tissue engineering...

  6. Microarray Analysis of microRNA Expression during Axolotl Limb Regeneration

    Science.gov (United States)

    Holman, Edna C.; Campbell, Leah J.; Hines, John; Crews, Craig M.

    2012-01-01

    Among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. The limb regeneration process in axolotls (Ambystoma mexicanum) has been well studied for decades at the cell-tissue level. While several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of microRNAs in urodele amphibian limb regeneration. Given the compelling evidence that many microRNAs tightly regulate cell fate and morphogenetic processes through development and adulthood by modulating the expression (or re-expression) of developmental genes, we investigated the possibility that microRNA levels change during limb regeneration. Using two different microarray platforms to compare the axolotl microRNA expression between mid-bud limb regenerating blastemas and non-regenerating stump tissues, we found that miR-21 was overexpressed in mid-bud blastemas compared to stump tissue. Mature A. mexicanum (“Amex”) miR-21 was detected in axolotl RNA by Northern blot and differential expression of Amex-miR-21 in blastema versus stump was confirmed by quantitative RT-PCR. We identified the Amex Jagged1 as a putative target gene for miR-21 during salamander limb regeneration. We cloned the full length 3′UTR of Amex-Jag1, and our in vitro assays demonstrated that its single miR-21 target recognition site is functional and essential for the response of the Jagged1 gene to miR-21 levels. Our findings pave the road for advanced in vivo functional assays aimed to clarify how microRNAs such as miR-21, often linked to pathogenic cell growth, might be modulating the redeployment of developmental genes such as Jagged1 during regenerative processes. PMID:23028429

  7. Microarray analysis of microRNA expression during axolotl limb regeneration.

    Directory of Open Access Journals (Sweden)

    Edna C Holman

    Full Text Available Among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. The limb regeneration process in axolotls (Ambystoma mexicanum has been well studied for decades at the cell-tissue level. While several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of microRNAs in urodele amphibian limb regeneration. Given the compelling evidence that many microRNAs tightly regulate cell fate and morphogenetic processes through development and adulthood by modulating the expression (or re-expression of developmental genes, we investigated the possibility that microRNA levels change during limb regeneration. Using two different microarray platforms to compare the axolotl microRNA expression between mid-bud limb regenerating blastemas and non-regenerating stump tissues, we found that miR-21 was overexpressed in mid-bud blastemas compared to stump tissue. Mature A. mexicanum ("Amex" miR-21 was detected in axolotl RNA by Northern blot and differential expression of Amex-miR-21 in blastema versus stump was confirmed by quantitative RT-PCR. We identified the Amex Jagged1 as a putative target gene for miR-21 during salamander limb regeneration. We cloned the full length 3'UTR of Amex-Jag1, and our in vitro assays demonstrated that its single miR-21 target recognition site is functional and essential for the response of the Jagged1 gene to miR-21 levels. Our findings pave the road for advanced in vivo functional assays aimed to clarify how microRNAs such as miR-21, often linked to pathogenic cell growth, might be modulating the redeployment of developmental genes such as Jagged1 during regenerative processes.

  8. Characterization of TGFβ signaling during tail regeneration in the leopard Gecko (Eublepharis macularius).

    Science.gov (United States)

    Gilbert, Richard W D; Vickaryous, Matthew K; Viloria-Petit, Alicia M

    2013-07-01

    The transforming growth factor beta (TGFβ)/activin signaling pathway has a number of documented roles during wound healing and is increasingly appreciated as an essential component of multi-tissue regeneration that occurs in amphibians and fish. Among amniotes (reptiles and mammals), less is known due in part to the lack of an appropriate model organism capable of multi-tissue regeneration. The leopard gecko Eublepharis macularius is able to spontaneously, and repeatedly, regenerate its tail following tail loss. We examined the expression and localization of several key components of the TGFβ/activin signaling pathway during tail regeneration of the leopard gecko. We observed a marked increase in phosphorylated Smad2 expression within the regenerate blastema indicating active TGFβ/activin signaling. Interestingly, during early regeneration, TGFβ1 expression is limited whereas activin-βA is strongly upregulated. We also observe the expression of EMT transcription factors Snail1 and Snail2 in the blastema. Combined, these observations provide strong support for the importance of different TGFβ ligands during multi-tissue regeneration and the potential role of TGFβ/activin-induced EMT programs during this process. Copyright © 2013 Wiley Periodicals, Inc.

  9. Somatostatin-like peptide and regeneration capacities in planarians.

    Science.gov (United States)

    Bautz, A; Schilt, J

    1986-11-01

    The presence of a neuropeptide immunologically related to somatostatin (SRIF) has been investigated in the neurosecretory cells of two regenerating planarian species (Dugesia lugubris and Dendrocoelum lacteum). A correlation has been shown between the discharge of the SRIF-like-immunoreactive cells during the first hours after amputation and the capacity to regenerate, and between the persistence of numerous positive cells and the lack of regeneration. These results suggest that somatostatin might play a regulatory (inhibitory) role on the cellular proliferation which leads to the blastema edification.

  10. Distal Regeneration Involves the Age Dependent Activity of Branchial Sac Stem Cells in the Ascidian Ciona intestinalis.

    Science.gov (United States)

    Jeffery, William R

    2015-02-01

    Tunicates have high capacities for regeneration but the underlying mechanisms and their relationship to life cycle progression are not well understood. Here we investigate the regeneration of distal structures in the ascidian tunicate Ciona intestinalis . Analysis of regenerative potential along the proximal-distal body axis indicated that distal organs, such as the siphons, their pigmented sensory organs, and the neural complex, could only be replaced from body fragments containing the branchial sac. Distal regeneration involves the formation of a blastema composed of cells that undergo cell proliferation prior to differentiation and cells that differentiate without cell proliferation. Both cell types originate in the branchial sac and appear in the blastema at different times after distal injury. Whereas the branchial sac stem cells are present in young animals, they are depleted in old animals that have lost their regeneration capacity. Thus Ciona adults contain a population of age-related stem cells located in the branchial sac that are a source of precursors for distal body regeneration.

  11. A Conserved MicroRNA Regulatory Circuit Is Differentially Controlled during Limb/Appendage Regeneration.

    Directory of Open Access Journals (Sweden)

    Benjamin L King

    Full Text Available Although regenerative capacity is evident throughout the animal kingdom, it is not equally distributed throughout evolution. For instance, complex limb/appendage regeneration is muted in mammals but enhanced in amphibians and teleosts. The defining characteristic of limb/appendage regenerative systems is the formation of a dedifferentiated tissue, termed blastema, which serves as the progenitor reservoir for regenerating tissues. In order to identify a genetic signature that accompanies blastema formation, we employ next-generation sequencing to identify shared, differentially regulated mRNAs and noncoding RNAs in three different, highly regenerative animal systems: zebrafish caudal fins, bichir pectoral fins and axolotl forelimbs.These studies identified a core group of 5 microRNAs (miRNAs that were commonly upregulated and 5 miRNAs that were commonly downregulated, as well as 4 novel tRNAs fragments with sequences conserved with humans. To understand the potential function of these miRNAs, we built a network of 1,550 commonly differentially expressed mRNAs that had functional relationships to 11 orthologous blastema-associated genes. As miR-21 was the most highly upregulated and most highly expressed miRNA in all three models, we validated the expression of known target genes, including the tumor suppressor, pdcd4, and TGFβ receptor subunit, tgfbr2 and novel putative target genes such as the anti-apoptotic factor, bcl2l13, Choline kinase alpha, chka and the regulator of G-protein signaling, rgs5.Our extensive analysis of RNA-seq transcriptome profiling studies in three regenerative animal models, that diverged in evolution ~420 million years ago, reveals a common miRNA-regulated genetic network of blastema genes. These comparative studies extend our current understanding of limb/appendage regeneration by identifying previously unassociated blastema genes and the extensive regulation by miRNAs, which could serve as a foundation for future

  12. Neurotrophic regulation of fibroblast dedifferentiation during limb skeletal regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

    2010-01-15

    The ability of animals to repair tissue damage is widespread and impressive. Among tissues, the repair and remodeling of bone occurs during growth and in response to injury; however, loss of bone above a threshold amount is not regenerated, resulting in a "critical-size defect" (CSD). The development of therapies to replace or regenerate a CSD is a major focus of research in regenerative medicine and tissue engineering. Adult urodeles (salamanders) are unique in their ability to regenerate complex tissues perfectly, yet like mammals do not regenerate a CSD. We report on an experimental model for the regeneration of a CSD in the axolotl (the Excisional Regeneration Model) that allows for the identification of signals to induce fibroblast dedifferentiation and skeletal regeneration. This regenerative response is mediated in part by BMP signaling, as is the case in mammals; however, a complete regenerative response requires the induction of a population of undifferentiated, regeneration-competent cells. These cells can be induced by signaling from limb amputation to generate blastema cells that can be grafted to the wound, as well as by signaling from a nerve and a wound epithelium to induce blastema cells from fibroblasts within the wound environment. Copyright 2009 Elsevier Inc. All rights reserved.

  13. Wnt/β-Catenin Signaling Defines Organizing Centers that Orchestrate Growth and Differentiation of the Regenerating Zebrafish Caudal Fin

    Directory of Open Access Journals (Sweden)

    Daniel Wehner

    2014-02-01

    Full Text Available Zebrafish regenerate their fins via the formation of a population of progenitor cells, the blastema. Wnt/β-catenin signaling is essential for blastemal cell proliferation and patterning of the overlying epidermis. Yet, we find that β-catenin signaling is neither active in the epidermis nor the majority of the proliferative blastemal cells. Rather, tissue-specific pathway interference indicates that Wnt signaling in the nonproliferative distal blastema is required for cell proliferation in the proximal blastema, and signaling in cells lining the osteoblasts directs osteoblast differentiation. Thus, Wnt signaling regulates epidermal patterning, blastemal cell proliferation, and osteoblast maturation indirectly via secondary signals. Gene expression profiling, chromatin immunoprecipitation, and functional rescue experiments suggest that Wnt/β-catenin signaling acts through Fgf and Bmp signaling to control epidermal patterning, whereas retinoic acid and Hedgehog signals mediate its effects on blastemal cell proliferation. We propose that Wnt signaling orchestrates fin regeneration by defining organizing centers that instruct cellular behaviors of adjacent tissues.

  14. Distal regeneration involves the age dependent activity of branchial sac stem cells in the ascidian Ciona intestinalis

    Science.gov (United States)

    2014-01-01

    Abstract Tunicates have high capacities for regeneration but the underlying mechanisms and their relationship to life cycle progression are not well understood. Here we investigate the regeneration of distal structures in the ascidian tunicate Ciona intestinalis. Analysis of regenerative potential along the proximal−distal body axis indicated that distal organs, such as the siphons, their pigmented sensory organs, and the neural complex, could only be replaced from body fragments containing the branchial sac. Distal regeneration involves the formation of a blastema composed of cells that undergo cell proliferation prior to differentiation and cells that differentiate without cell proliferation. Both cell types originate in the branchial sac and appear in the blastema at different times after distal injury. Whereas the branchial sac stem cells are present in young animals, they are depleted in old animals that have lost their regeneration capacity. Thus Ciona adults contain a population of age‐related stem cells located in the branchial sac that are a source of precursors for distal body regeneration. PMID:25893097

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

    Science.gov (United States)

    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.

  16. Differential expression of myogenic regulatory genes and Msx-1 during dedifferentiation and redifferentiation of regenerating amphibian limbs.

    Science.gov (United States)

    Simon, H G; Nelson, C; Goff, D; Laufer, E; Morgan, B A; Tabin, C

    1995-01-01

    An amputated limb of an adult urodele amphibian is capable of undergoing regeneration. The new structures form from an undifferentiated mass of cells called the regenerative blastema. The cells of the blastema are believed to derive from differentiated tissues of the adult limb. However, the exact source of these cells and the process by which they undergo dedifferentiation are poorly understood. In order to elucidate the molecular and cellular basis for dedifferentiation we isolated a number of genes which are potential regulators of the process. These include Msx-1, which is believed to support the undifferentiated and proliferative state of cells in the embryonic limb bud; and two members of the myogenic regulatory gene family, MRF-4 and Myf-5, which are expressed in differentiated muscle and regulate muscle-specific gene activity. As anticipated, we find that Msx-1 is strongly up-regulated during the initiation of regeneration. It remains expressed throughout regeneration but is not found in the fully regenerated limb. The myogenic gene MRF-4 has the reverse expression pattern. It is expressed in adult limb muscle, is rapidly shut off in early regenerative blastemas, and is only reexpressed at the completion of regeneration. These kinetics are paralleled by those of a muscle-specific Myosin gene. In contrast Myf-5, a second member of the myogenic gene family, continues to be expressed throughout the regenerative process. Thus, MRF-4 and Myf-5 are likely to play distinct roles during regeneration. MRF-4 may directly regulate muscle phenotype and as such its repression may be a key event in dedifferentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Regulation of Regenerative Responses by Factors in the Extracellular Matrix during Axolotl (Ambystoma mexicanum) Limb Regeneration

    OpenAIRE

    Phan, Anne Quy

    2014-01-01

    Salamanders are unique among adult vertebrates in their ability to regenerate complex body structures after traumatic injury. Axolotl limb regeneration is a stepwise sequence of three requisite processes: (1) scarless wound healing to generate a regenerative wound epithelium, (2) blastema formation by migration, proliferation and dedifferentiation to create a mass of multipotent regeneration-competent progenitor cells, and (3) induction of pattern formation by interaction of cells with opposi...

  18. The anatomy and histology of caudal autotomy and regeneration in lizards.

    Science.gov (United States)

    Gilbert, Emily A B; Payne, Samantha L; Vickaryous, Matthew K

    2013-01-01

    Abstract Caudal autotomy-the ability to self-detach the tail-is a dramatic adaptation common to many structural-grade lizards. For most species, tail loss is followed by the equally dramatic phenomenon of tail regeneration. Here we review the anatomy and histology of caudal autotomy and regeneration in lizards, drawing heavily from research published over the past 2 decades. The autotomous tail is characterized by various structural adaptations, which act to minimize blood loss and trauma to adjacent tissues. The early phase of wound healing involves a leukocytic response but limited inflammation. Reepithelialization via a specialized wound epithelium is not only critical for scar-free healing but also necessary for subsequent tissue patterning and regenerative outgrowth. Regeneration begins with the formation of the blastema, a mass of proliferating mesenchymal-like cells. As the blastema expands, it is invaded by blood vessels and the spinal cord. Whereas the replacement tail outwardly resembles the original appendage, it differs in several notable respects, including the tissue composition and organization of the skeleton, muscular system, and spinal cord. Increasingly, the lizard tail is being recognized among biomedical scientists as an important model for the study of wound healing and multitissue restoration.

  19. Neurotrophic regulation of epidermal dedifferentiation during wound healing and limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, A; Graham, G M C; Bryant, S V; Gardiner, D M

    2008-07-15

    Adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. The recently developed Accessory Limb Model (ALM) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. The ALM demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. When all the signals are present, a limb is formed de novo. The ALM thus provides an opportunity to identify and characterize the signaling pathways that control blastema morphogenesis and limb regeneration. In the present study, we have utilized the ALM to identity the buttonhead-like zinc-finger transcription factor, Sp9, as being involved in the formation of the regeneration epithelium. Sp9 expression is induced in basal keratinocytes of the apical blastema epithelium in a pattern that is comparable to its expression in developing limb buds, and it thus is an important marker for dedifferentiation of the epidermis. Induction of Sp9 expression is nerve-dependent, and we have identified KGF as an endogenous nerve factor that induces expression of Sp9 in the regeneration epithelium.

  20. Cancer-related aspects of regeneration research: a review

    International Nuclear Information System (INIS)

    Donaldson, D.J.; Mason, J.M.

    1975-01-01

    Tissue regeneration is simply the replacement of lost cells of a tissue by those remaining. Epimorphic regeneration involves dedifferentiation of many tissues and their organization into a blastema which eventually differentiates into the missing part, usually an appendage. A detailed comparison of the cell membrane changes occurring in epimorphic regeneration, tissue regeneration and cancer can contribute to greater understanding of the differences between normal and tumor cells. Further, there is evidence that epimorphic regeneration fields may in some instances suppress tumor induction and control existing tumors. This influence may be mediated by bioelectric fields, which are ubiquitous in nature and appear to control many cellular events. Disruption of these bioelectric fields suppresses epimorphic regeneration and may lead to cancer in mammals, while applied electric fields alter regenerative events and cause tumor regression. Studies on x-radioinduced regeneration suppression in relation to mutagenesis are also reviewed

  1. Macrophages are necessary for epimorphic regeneration in African spiny mice.

    Science.gov (United States)

    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.

  2. Hyperbaric oxygen therapy in a true regenerative environment, the regenerating limb of the axolotl

    DEFF Research Database (Denmark)

    Hansen, Kasper; Lauridsen, Henrik; Pedersen, Michael

    2012-01-01

    vertebrates such as the urodele amphibians (salamanders and newts), are excellent animal models for regenerative studies. The iconic Mexican axolotl (Ambystoma mexicanum) is capable of regenerating whole limbs, tail, jaw, and many inner organs, by dedifferentiation of cells to form a blastema (collection...

  3. Collagen reconstitution is inversely correlated with induction of limb regeneration in Ambystoma mexicanum.

    Science.gov (United States)

    Satoh, Akira; Hirata, Ayako; Makanae, Aki

    2012-03-01

    Amphibians can regenerate missing body parts, including limbs. The regulation of collagen has been considered to be important in limb regeneration. Collagen deposition is suppressed during limb regeneration, so we investigated collagen deposition and apical epithelial cap (AEC) formation during axolotl limb regeneration. The accessory limb model (ALM) has been developed as an alternative model for studying limb regeneration. Using this model, we investigated the relationship between nerves, epidermis, and collagen deposition. We found that Sp-9, an AEC marker gene, was upregulated by direct interaction between nerves and epidermis. However, collagen deposition hindered this interaction, and resulted in the failure of limb regeneration. During wound healing, an increase in deposition of collagen caused a decrease in the blastema induction rate in ALM. Wound healing and limb regeneration are alternate processes.

  4. DNA Methylation Dynamics Regulate the Formation of a Regenerative Wound Epithelium during Axolotl Limb Regeneration.

    Directory of Open Access Journals (Sweden)

    Cristian Aguilar

    Full Text Available The formation of a blastema during regeneration of an axolotl limb involves important changes in the behavior and function of cells at the site of injury. One of the earliest events is the formation of the wound epithelium and subsequently the apical epidermal cap, which involves in vivo dedifferentiation that is controlled by signaling from the nerve. We have investigated the role of epigenetic modifications to the genome as a possible mechanism for regulating changes in gene expression patterns of keratinocytes of the wound and blastema epithelium that are involved in regeneration. We report a modulation of the expression DNMT3a, a de novo DNA methyltransferase, within the first 72 hours post injury that is dependent on nerve signaling. Treatment of skin wounds on the upper forelimb with decitabine, a DNA methyltransferase inhibitor, induced changes in gene expression and cellular behavior associated with a regenerative response. Furthermore, decitabine-treated wounds were able to participate in regeneration while untreated wounds inhibited a regenerative response. Elucidation of the specific epigenetic modifications that mediate cellular dedifferentiation likely will lead to insights for initiating a regenerative response in organisms that lack this ability.

  5. Inhibition of apoptosis signal-regulating kinase 1 alters the wound epidermis and enhances auricular cartilage regeneration.

    Directory of Open Access Journals (Sweden)

    Qian-Shi Zhang

    Full Text Available Why regeneration does not occur in mammals remains elusive. In lower vertebrates, epimorphic regeneration of the limb is directed by the wound epidermis, which controls blastema formation to promote regrowth of the appendage. Herein, we report that knockout (KO or inhibition of Apoptosis Signal-regulated Kinase-1 (ASK1, also known as mitogen-activated protein kinase kinase kinase 5 (MAP3K5, after full thickness ear punch in mice prolongs keratinocyte activation within the wound epidermis and promotes regeneration of auricular cartilage. Histological analysis showed the ASK1 KO ears displayed enhanced protein markers associated with blastema formation, hole closure and regeneration of auricular cartilage. At seven days after punch, the wound epidermis morphology was markedly different in the KO, showing a thickened stratum corneum with rounded cell morphology and a reduction of both the granular cell layer and decreased expression of filament aggregating protein. In addition, cytokeratin 6 was expressed in the stratum spinosum and granulosum. Topical application of inhibitors of ASK1 (NQDI-1, the upstream ASK1 activator, calcium activated mitogen kinase 2 (KN93, or the downstream target, c-Jun N-terminal kinase (SP600125 also resulted in enhanced regeneration; whereas inhibition of the other downstream target, the p38 α/β isoforms, (SB203580 had no effect. The results of this investigation indicate ASK1 inhibition prolongs keratinocyte and blastemal cell activation leading to ear regeneration.

  6. Inhibition of apoptosis signal-regulating kinase 1 alters the wound epidermis and enhances auricular cartilage regeneration

    Science.gov (United States)

    Zhang, Qian-Shi; Kurpad, Deepa S.; Mahoney, My G.; Steinbeck, Marla J.

    2017-01-01

    Why regeneration does not occur in mammals remains elusive. In lower vertebrates, epimorphic regeneration of the limb is directed by the wound epidermis, which controls blastema formation to promote regrowth of the appendage. Herein, we report that knockout (KO) or inhibition of Apoptosis Signal-regulated Kinase-1 (ASK1), also known as mitogen-activated protein kinase kinase kinase 5 (MAP3K5), after full thickness ear punch in mice prolongs keratinocyte activation within the wound epidermis and promotes regeneration of auricular cartilage. Histological analysis showed the ASK1 KO ears displayed enhanced protein markers associated with blastema formation, hole closure and regeneration of auricular cartilage. At seven days after punch, the wound epidermis morphology was markedly different in the KO, showing a thickened stratum corneum with rounded cell morphology and a reduction of both the granular cell layer and decreased expression of filament aggregating protein. In addition, cytokeratin 6 was expressed in the stratum spinosum and granulosum. Topical application of inhibitors of ASK1 (NQDI-1), the upstream ASK1 activator, calcium activated mitogen kinase 2 (KN93), or the downstream target, c-Jun N-terminal kinase (SP600125) also resulted in enhanced regeneration; whereas inhibition of the other downstream target, the p38 α/β isoforms, (SB203580) had no effect. The results of this investigation indicate ASK1 inhibition prolongs keratinocyte and blastemal cell activation leading to ear regeneration. PMID:29045420

  7. Serum Proteases Potentiate BMP-Induced Cell Cycle Re-entry of Dedifferentiating Muscle Cells during Newt Limb Regeneration

    NARCIS (Netherlands)

    Wagner, Ines; Wang, Heng; Weissert, Philipp M.; Straube, Werner L.; Shevchenko, Anna; Gentzel, Marc; Brito, Goncalo; Tazaki, Akira; Oliveira, Catarina; Sugiura, Takuji; Shevchenko, Andrej; Simon, Andras; Drechsel, David N.; Tanaka, Elly M.

    2017-01-01

    Limb amputation in the newt induces myofibers to dedifferentiate and re-enter the cell cycle to generate proliferative myogenic precursors in the regeneration blastema. Here we show that bone morphogenetic proteins (BMPs) and mature BMPs that have been further cleaved by serum proteases induce cell

  8. Scar-free wound healing and regeneration following tail loss in the leopard gecko, Eublepharis macularius.

    Science.gov (United States)

    Delorme, Stephanie Lynn; Lungu, Ilinca Mihaela; Vickaryous, Matthew Kenneth

    2012-10-01

    Many lizards are able to undergo scar-free wound healing and regeneration following loss of the tail. In most instances, lizard tail loss is facilitated by autotomy, an evolved mechanism that permits the tail to be self-detached at pre-existing fracture planes. However, it has also been reported that the tail can regenerate following surgical amputation outside the fracture plane. In this study, we used the leopard gecko, Eublepharis macularius, to investigate and compare wound healing and regeneration following autotomy at a fracture plane and amputation outside the fracture plane. Both forms of tail loss undergo a nearly identical sequence of events leading to scar-free wound healing and regeneration. Early wound healing is characterized by transient myofibroblasts and the formation of a highly proliferative wound epithelium immunoreactive for the wound keratin marker WE6. The new tail forms from what is commonly referred to as a blastema, a mass of proliferating mesenchymal-like cells. Blastema cells express the protease matrix metalloproteinase-9. Apoptosis (demonstrated by activated caspase 3 immunostaining) is largely restricted to isolated cells of the original and regenerating tail tissues, although cell death also occurs within dermal structures at the original-regenerated tissue interface and among clusters of newly formed myocytes. Furthermore, the autotomized tail is unique in demonstrating apoptosis among cells adjacent to the fracture planes. Unlike mammals, transforming growth factor-β3 is not involved in wound healing. We demonstrate that scar-free wound healing and regeneration are intrinsic properties of the tail, unrelated to the location or mode of tail detachment. Copyright © 2012 Wiley Periodicals, Inc.

  9. Reactivation of X-irradiated cell material during limb regeneration in Urodeles Amphibians

    International Nuclear Information System (INIS)

    Desselle, J.C.

    1979-10-01

    In amputated members irradiated with X-rays the regeneration power is inhibited. This power is restored by grafts of healthy tissue in the irradiated members. The origin of the cell material of the restored regeneration blastema has been studied by an original labelling technique. The different amounts of DNA in the graft cells and those of the stump mark the graft cells during the regeneration process. It was shown that the graft causes a reactivation of the inhibited stump cells and the reactivation stages are the same as the activation stages of the member regenerating normally. It was also established that during restored regeneration the cell material implanted in the irradiated members contributes, by the 160th day of regeneration, 4.5% of the cartilaginous regenerate cells and 12% of the muscle cells. All the other regenerate cells are supplied by the cells of the stump; these are reactivated and together with the activated graft cells lead to the restitution of the amputated member [fr

  10. Atmospheric pressure plasma accelerates tail regeneration in tadpoles Xenopus laevis

    Science.gov (United States)

    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.

  11. A Tissue-Mapped Axolotl De Novo Transcriptome Enables Identification of Limb Regeneration Factors

    Directory of Open Access Journals (Sweden)

    Donald M. Bryant

    2017-01-01

    Full Text Available Mammals have extremely limited regenerative capabilities; however, axolotls are profoundly regenerative and can replace entire limbs. The mechanisms underlying limb regeneration remain poorly understood, partly because the enormous and incompletely sequenced genomes of axolotls have hindered the study of genes facilitating regeneration. We assembled and annotated a de novo transcriptome using RNA-sequencing profiles for a broad spectrum of tissues that is estimated to have near-complete sequence information for 88% of axolotl genes. We devised expression analyses that identified the axolotl orthologs of cirbp and kazald1 as highly expressed and enriched in blastemas. Using morpholino anti-sense oligonucleotides, we find evidence that cirbp plays a cytoprotective role during limb regeneration whereas manipulation of kazald1 expression disrupts regeneration. Our transcriptome and annotation resources greatly complement previous transcriptomic studies and will be a valuable resource for future research in regenerative biology.

  12. Microarray and cDNA sequence analysis of transcription during nerve-dependent limb regeneration

    Directory of Open Access Journals (Sweden)

    Bryant Susan V

    2009-01-01

    Full Text Available Abstract Background Microarray analysis and 454 cDNA sequencing were used to investigate a centuries-old problem in regenerative biology: the basis of nerve-dependent limb regeneration in salamanders. Innervated (NR and denervated (DL forelimbs of Mexican axolotls were amputated and transcripts were sampled after 0, 5, and 14 days of regeneration. Results Considerable similarity was observed between NR and DL transcriptional programs at 5 and 14 days post amputation (dpa. Genes with extracellular functions that are critical to wound healing were upregulated while muscle-specific genes were downregulated. Thus, many processes that are regulated during early limb regeneration do not depend upon nerve-derived factors. The majority of the transcriptional differences between NR and DL limbs were correlated with blastema formation; cell numbers increased in NR limbs after 5 dpa and this yielded distinct transcriptional signatures of cell proliferation in NR limbs at 14 dpa. These transcriptional signatures were not observed in DL limbs. Instead, gene expression changes within DL limbs suggest more diverse and protracted wound-healing responses. 454 cDNA sequencing complemented the microarray analysis by providing deeper sampling of transcriptional programs and associated biological processes. Assembly of new 454 cDNA sequences with existing expressed sequence tag (EST contigs from the Ambystoma EST database more than doubled (3935 to 9411 the number of non-redundant human-A. mexicanum orthologous sequences. Conclusion Many new candidate gene sequences were discovered for the first time and these will greatly enable future studies of wound healing, epigenetics, genome stability, and nerve-dependent blastema formation and outgrowth using the axolotl model.

  13. Regulation of proximal-distal intercalation during limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

    2010-12-01

    Intercalation is the process whereby cells located at the boundary of a wound interact to stimulate proliferation and the restoration of the structures between the boundaries that were lost during wounding. Thus, intercalation is widely considered to be the mechanism of regeneration. When a salamander limb is amputated, the entire cascade of regeneration events is activated, and the missing limb segments and their boundaries (joints) as well as the structures within each segment are regenerated. Therefore, in an amputated limb it is not possible to distinguish between intersegmental regeneration (formation of new segments/joints) and intrasegmental regeneration (formation of structures within a given segment), and it is not possible to study the differential regulation of these two processes. We have used two models for regeneration that allow us to study these two processes independently, and report that inter- and intrasegmental regeneration are different processes regulated by different signaling pathways. New limb segments/joints can be regenerated from cells that dedifferentiate to form blastema cells in response to signaling that is mediated in part by fibroblast growth factor. © 2010 The Authors. Journal compilation © 2010 Japanese Society of Developmental Biologists.

  14. FGF and BMP derived from dorsal root ganglia regulate blastema induction in limb regeneration in Ambystoma mexicanum.

    Science.gov (United States)

    Satoh, Akira; Makanae, Aki; Nishimoto, Yurie; Mitogawa, Kazumasa

    2016-09-01

    Urodele amphibians have a remarkable organ regeneration ability that is regulated by neural inputs. The identification of these neural inputs has been a challenge. Recently, Fibroblast growth factor (Fgf) and Bone morphogenic protein (Bmp) were shown to substitute for nerve functions in limb and tail regeneration in urodele amphibians. However, direct evidence of Fgf and Bmp being secreted from nerve endings and regulating regeneration has not yet been shown. Thus, it remained uncertain whether they were the nerve factors responsible for successful limb regeneration. To gather experimental evidence, the technical difficulties involved in the usage of axolotls had to be overcome. We achieved this by modifying the electroporation method. When Fgf8-AcGFP or Bmp7-AcGFP was electroporated into the axolotl dorsal root ganglia (DRG), GFP signals were detectable in the regenerating limb region. This suggested that Fgf8 and Bmp7 synthesized in neural cells in the DRG were delivered to the limbs through the long axons. Further knockdown experiments with double-stranded RNA interference resulted in impaired limb regeneration ability. These results strongly suggest that Fgf and Bmp are the major neural inputs that control the organ regeneration ability. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Toxic responses of Sox2 gene in the regeneration of the earthworm Eisenia foetida exposed to Retnoic acid.

    Science.gov (United States)

    Tao, Jing; Rong, Wei; Diao, Xiaoping; Zhou, Hailong

    2018-01-01

    Exogenous retinoic acid delays and disturbs the regeneration of Eisenia foetida. The stem cell pluripotency factor, Sox2, can play a crucial role in cell reprogramming and dedifferentiation. In this study, we compared the regeneration of Eisenia foetida in different segments after amputation and the effects of retinoic acid on the regeneration of different segments. The results showed that the regeneration speed of the head and tail was slightly faster than the middle part, and retinoic acid disrupted and delayed the regeneration of the earthworm. The qRT-PCR and Western blot analysis showed that the expression of the Sox2 gene and Sox2 protein was highest on the seventh day in different segments (pregeneration of earthworms and the formation of blastema are related to the expression of the Sox2 gene and protein. Retinoic acid delays and interferes with the regeneration of the earthworm by affecting the expression levels of the Sox2 gene and protein. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Orthogonal muscle fibres have different instructive roles in planarian regeneration.

    Science.gov (United States)

    Scimone, M Lucila; Cote, Lauren E; Reddien, Peter W

    2017-11-30

    The ability to regenerate missing body parts exists throughout the animal kingdom. Positional information is crucial for regeneration, but how it is harboured and used by differentiated tissues is poorly understood. In planarians, positional information has been identified from study of phenotypes caused by RNA interference in which the wrong tissues are regenerated. For example, inhibition of the Wnt signalling pathway leads to regeneration of heads in place of tails. Characterization of these phenotypes has led to the identification of position control genes (PCGs)-genes that are expressed in a constitutive and regional manner and are associated with patterning. Most PCGs are expressed within planarian muscle; however, how muscle is specified and how different muscle subsets affect regeneration is unknown. Here we show that different muscle fibres have distinct regulatory roles during regeneration in the planarian Schmidtea mediterranea. myoD is required for formation of a specific muscle cell subset: the longitudinal fibres, oriented along the anterior-posterior axis. Loss of longitudinal fibres led to complete regeneration failure because of defects in regeneration initiation. A different transcription factor-encoding gene, nkx1-1, is required for the formation of circular fibres, oriented along the medial-lateral axis. Loss of circular fibres led to a bifurcated anterior-posterior axis with fused heads forming in single anterior blastemas. Whereas muscle is often viewed as a strictly contractile tissue, these findings reveal that different muscle types have distinct and specific regulatory roles in wound signalling and patterning to enable regeneration.

  17. Wound repair during arm regeneration in the red starfish Echinaster sepositus

    KAUST Repository

    Ben Khadra, Yousra

    2015-06-24

    Starfish can regenerate entire arms following their loss by both autotomic and traumatic amputation. Although the overall regenerative process has been studied several times in different asteroid species, there is still a considerable gap of knowledge as far as the detailed aspects of the repair phase at tissue and cellular level are concerned, particularly in post-traumatic regeneration. The present work is focused on the arm regeneration model in the Mediterranean red starfish Echinaster sepositus; in order to describe the early cellular mechanisms of arm regeneration following traumatic amputation, different microscopy techniques were employed. In E. sepositus, the repair phase was characterized by prompt wound healing by a syncytial network of phagocytes and re-epithelialisation followed by a localized subepidermal oedematous area formation. Scattered and apparently undifferentiated cells, intermixed with numerous phagocytes, were frequently found in the wound area during these first stages of regeneration and extensive dedifferentiation phenomena were seen at the level of the stump, particularly in the muscle bundles. A true localized blastema did not form. Our results confirm that regeneration in asteroids mainly relies on morphallactic processes, consisting in extensive rearrangement of the existing tissues which contribute to the new tissues through cell dedifferentiation, re-differentiation and/or migration. This article is protected by copyright. All rights reserved.

  18. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Poole, Loree Joanne [Univ. of California, Berkeley, CA (United States); King, C. Judson [Univ. of California, Berkeley, CA (United States)

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO2 and H2S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The

  19. The Effect of Plasma Exposure on Tail Regeneration of Tadpoles Xenopus Laevis

    Science.gov (United States)

    June, Joyce; Rivie, Adonis; Ezuduemoih, Raphael; Menon, Jaishri; Martus, Kevin

    2014-03-01

    Wound healing requires a balanced combination of nutrients and growth factors for healing and tissue regeneration. The effect of plasma exposure on tail regeneration of tadpoles, Xenopus laevis is investigated. The exposure of the wound to the helium plasma immediately followed the amputation of 40% of the tail. Amputation of the tail initiates regeneration of spinal cord, muscle, notochord, skin and connective tissues. By 24 h, the wound was covered by wound epithelium and blastema was formed by day 5. There was increased angiogenesis in plasma exposed tail regenerate compared to the control following 5 d post amputation. Observed was an increase in NO production in the regenerate of plasma exposed tadpoles was derived from increased activity of nNOS and iNOS. Western blot analysis for vascular endothelial growth factor showed stronger bands for the protein in amputated tadpoles of both the groups. Analysis of the composition and characteristics of the plasma using optical emission spectroscopy indicates excited state species consisting of N2, N2+,and OH is present in the plasma. This study was supported, in part, by the NSF Grant 1040108.

  20. Gallium nitrate: effects on cartilage during limb regeneration in the axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Tassava, Roy A; Mendenhall, Luciara; Apseloff, Glen; Gerber, Nicholas

    2002-09-01

    Gallium nitrate, a drug shown to have efficacy in Paget's disease of bone, hypercalcemia of malignancy, and a variety of experimental autoimmune diseases, also inhibits the growth of some types of cancer. We examined dose and timing of administration of gallium nitrate on limb regeneration in the Mexican axolotl, Ambystoma mexicanum. Administered by intraperitoneal injection, gallium nitrate inhibited limb regeneration in a dose-dependent manner. Gallium nitrate initially suppressed epithelial wound healing and subsequently distorted both anterior-posterior and proximo-distal chondrogenic patterns. Gallium nitrate given at three days after amputation severely inhibited regeneration at high doses (6.25 mg/axolotl) and altered the normal patterning of the regenerates at low doses (3.75 mg/axolotl). Administration of 6.25 mg of gallium nitrate at four or 14 days prior to amputation also inhibited regeneration. In amputated limbs of gallium-treated axolotls, the chondrocytes were lost from inside the radius/ulna. Limbs that regenerated after gallium treatment was terminated showed blastema formation preferentially over the ulna. New cartilage of the regenerate often attached to the sides of the existing radius/ulna proximally into the stump and less so to the distal cut ends. J. Exp. Zool. 293:384-394, 2002. Copyright 2002 Wiley-Liss, Inc.

  1. Serum Proteases Potentiate BMP-Induced Cell Cycle Re-entry of Dedifferentiating Muscle Cells during Newt Limb Regeneration.

    Science.gov (United States)

    Wagner, Ines; Wang, Heng; Weissert, Philipp M; Straube, Werner L; Shevchenko, Anna; Gentzel, Marc; Brito, Goncalo; Tazaki, Akira; Oliveira, Catarina; Sugiura, Takuji; Shevchenko, Andrej; Simon, András; Drechsel, David N; Tanaka, Elly M

    2017-03-27

    Limb amputation in the newt induces myofibers to dedifferentiate and re-enter the cell cycle to generate proliferative myogenic precursors in the regeneration blastema. Here we show that bone morphogenetic proteins (BMPs) and mature BMPs that have been further cleaved by serum proteases induce cell cycle entry by dedifferentiating newt muscle cells. Protease-activated BMP4/7 heterodimers that are present in serum strongly induced myotube cell cycle re-entry with protease cleavage yielding a 30-fold potency increase of BMP4/7 compared with canonical BMP4/7. Inhibition of BMP signaling via muscle-specific dominant-negative receptor expression reduced cell cycle entry in vitro and in vivo. In vivo inhibition of serine protease activity depressed cell cycle re-entry, which in turn was rescued by cleaved-mimic BMP. This work identifies a mechanism of BMP activation that generates blastema cells from differentiated muscle. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Neoblast Specialization in Regeneration of the Planarian Schmidtea mediterranea

    Directory of Open Access Journals (Sweden)

    M. Lucila Scimone

    2014-08-01

    Full Text Available Planarians can regenerate any missing body part in a process requiring dividing cells called neoblasts. Historically, neoblasts have largely been considered a homogeneous stem cell population. Most studies, however, analyzed neoblasts at the population rather than the single-cell level, leaving the degree of heterogeneity in this population unresolved. We combined RNA sequencing of neoblasts from wounded planarians with expression screening and identified 33 transcription factors transcribed in specific differentiated cells and in small fractions of neoblasts during regeneration. Many neoblast subsets expressing distinct tissue-associated transcription factors were present, suggesting candidate specification into many lineages. Consistent with this possibility, klf, pax3/7, and FoxA were required for the differentiation of cintillo-expressing sensory neurons, dopamine-β-hydroxylase-expressing neurons, and the pharynx, respectively. Together, these results suggest that specification of cell fate for most-to-all regenerative lineages occurs within neoblasts, with regenerative cells of blastemas being generated from a highly heterogeneous collection of lineage-specified neoblasts.

  3. Gene expression profiles of fin regeneration in loach (Paramisgurnus dabryanu).

    Science.gov (United States)

    Li, Li; He, Jingya; Wang, Linlin; Chen, Weihua; Chang, Zhongjie

    2017-11-01

    Teleost fins can regenerate accurate position-matched structure and function after amputation. However, we still lack systematic transcriptional profiling and methodologies to understand the molecular basis of fin regeneration. After histological analysis, we established a suppression subtraction hybridization library containing 418 distinct sequences expressed differentially during the process of blastema formation and differentiation in caudal fin regeneration. Genome ontology and comparative analysis of differential distribution of our data and the reference zebrafish genome showed notable subcategories, including multi-organism processes, response to stimuli, extracellular matrix, antioxidant activity, and cell junction function. KEGG pathway analysis allowed the effective identification of relevant genes in those pathways involved in tissue morphogenesis and regeneration, including tight junction, cell adhesion molecules, mTOR and Jak-STAT signaling pathway. From relevant function subcategories and signaling pathways, 78 clones were examined for further Southern-blot hybridization. Then, 17 genes were chosen and characterized using semi-quantitative PCR. Then 4 candidate genes were identified, including F11r, Mmp9, Agr2 and one without a match to any database. After real-time quantitative PCR, the results showed obvious expression changes in different periods of caudal fin regeneration. We can assume that the 4 candidates, likely valuable genes associated with fin regeneration, deserve additional attention. Thus, our study demonstrated how to investigate the transcript profiles with an emphasis on bioinformatics intervention and how to identify potential genes related to fin regeneration processes. The results also provide a foundation or knowledge for further research into genes and molecular mechanisms of fin regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Djhsp90s are crucial regulators during planarian regeneration and tissue homeostasis.

    Science.gov (United States)

    Dong, Zimei; Chu, Gengbo; Sima, Yingxu; Chen, Guangwen

    2018-04-15

    Heat shock protein 90 family members (HSP90s), as molecular chaperones, have conserved roles in the physiological processes of eukaryotes regulating cytoprotection, increasing host resistance and so on. However, whether HSP90s affect regeneration in animals is unclear. Planarians are emerging models for studying regeneration in vivo. Here, the roles of three hsp90 genes from planarian Dugesia japonica are investigated by WISH and RNAi. The results show that: (1) Djhsp90s expressions are induced by heat and cold shock, tissue damage and ionic liquid; (2) Djhsp90s mRNA are mainly distributed each side of the body in intact worms as well as blastemas in regenerative worms; (3) the worms show head regression, lysis, the body curling and the regeneration arrest or even failure after Djhsp90s RNAi; (4) Djhsp90s are involved in autophagy and locomotion of the body. The research results suggest that Djhsp90s are not only conserved in cytoprotection, but also involved in homeostasis maintenance and regeneration process by regulating different pathways in planarians. Copyright © 2018 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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

  6. Regeneration strategies of polymers employed in ex-situ remediation of contaminated soil: Bioregeneration versus solvent extraction.

    Science.gov (United States)

    Mosca Angelucci, Domenica; Tomei, M Concetta

    2015-08-15

    In this study we evaluated the feasibility of two regeneration strategies of contaminated polymers employed for ex-situ soil remediation in a two-step process. Soil decontamination is achieved by sorption of the pollutants on the polymer beads, which are regenerated in a subsequent step. Tested soil was contaminated with a mixture of 4-chlorophenol and pentachlorophenol, and a commercial polymer, Hytrel, has been employed for extraction. Removal efficiencies of the polymer-soil extraction are in the range of 51-97% for a contact time ≤ 24 h. Two polymer regeneration strategies, solvent extraction and biological regeneration (realized in a two-phase partitioning bioreactor), were tested and compared. Performance was assessed in terms of removal rates and efficiencies and an economic analysis based on the operating costs has been performed. Results demonstrated the feasibility of both regeneration strategies, but the bioregeneration was advantageous in that provided the biodegradation of the contaminants desorbed from the polymer. Practically complete removal for 4-chlorophenol and up to 85% biodegradation efficiency for pentachlorophenol were achieved. Instead, in the solvent extraction, a relevant production (184-831 L kg(pol)(-1)) of a highly polluted stream to be treated or disposed of is observed. The cost analysis of the two strategies showed that the bioregeneration is much more convenient with operating costs of ∼12 €/kg(pol) i.e. more than one order of magnitude lower in comparison to ∼233 €/kg(pol) of the solvent extraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. CRISPR-Mediated Genomic Deletion of Sox2 in the Axolotl Shows a Requirement in Spinal Cord Neural Stem Cell Amplification during Tail Regeneration

    Directory of Open Access Journals (Sweden)

    Ji-Feng Fei

    2014-09-01

    Full Text Available The salamander is the only tetrapod that functionally regenerates all cell types of the limb and spinal cord (SC and thus represents an important regeneration model, but the lack of gene-knockout technology has limited molecular analysis. We compared transcriptional activator-like effector nucleases (TALENs and clustered regularly interspaced short palindromic repeats (CRISPRs in the knockout of three loci in the axolotl and find that CRISPRs show highly penetrant knockout with less toxic effects compared to TALENs. Deletion of Sox2 in up to 100% of cells yielded viable F0 larvae with normal SC organization and ependymoglial cell marker expression such as GFAP and ZO-1. However, upon tail amputation, neural stem cell proliferation was inhibited, resulting in spinal-cord-specific regeneration failure. In contrast, the mesodermal blastema formed normally. Sox3 expression during development, but not regeneration, most likely allowed embryonic survival and the regeneration-specific phenotype. This analysis represents the first tissue-specific regeneration phenotype from the genomic deletion of a gene in the axolotl.

  8. Positional information in axolotl and mouse limb extracellular matrix is mediated via heparan sulfate and fibroblast growth factor during limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Phan, Anne Q; Lee, Jangwoo; Oei, Michelle; Flath, Craig; Hwe, Caitlyn; Mariano, Rachele; Vu, Tiffany; Shu, Cynthia; Dinh, Andrew; Simkin, Jennifer; Muneoka, Ken; Bryant, Susan V; Gardiner, David M

    2015-08-01

    Urodele amphibians are unique among adult vertebrates in their ability to regenerate complex body structures after traumatic injury. In salamander regeneration, the cells maintain a memory of their original position and use this positional information to recreate the missing pattern. We used an in vivo gain-of-function assay to determine whether components of the extracellular matrix (ECM) have positional information required to induce formation of new limb pattern during regeneration. We discovered that salamander limb ECM has a position-specific ability to either inhibit regeneration or induce de novo limb structure, and that this difference is dependent on heparan sulfates that are associated with differential expression of heparan sulfate sulfotransferases. We also discovered that an artificial ECM containing only heparan sulfate was sufficient to induce de novo limb pattern in salamander limb regeneration. Finally, ECM from mouse limbs is capable of inducing limb pattern in axolotl blastemas in a position-specific, developmental-stage-specific, and heparan sulfate-dependent manner. This study demonstrates a mechanism for positional information in regeneration and establishes a crucial functional link between salamander regeneration and mammals.

  9. Transcriptomic analysis of tail regeneration in the lizard Anolis carolinensis reveals activation of conserved vertebrate developmental and repair mechanisms.

    Directory of Open Access Journals (Sweden)

    Elizabeth D Hutchins

    Full Text Available Lizards, which are amniote vertebrates like humans, are able to lose and regenerate a functional tail. Understanding the molecular basis of this process would advance regenerative approaches in amniotes, including humans. We have carried out the first transcriptomic analysis of tail regeneration in a lizard, the green anole Anolis carolinensis, which revealed 326 differentially expressed genes activating multiple developmental and repair mechanisms. Specifically, genes involved in wound response, hormonal regulation, musculoskeletal development, and the Wnt and MAPK/FGF pathways were differentially expressed along the regenerating tail axis. Furthermore, we identified 2 microRNA precursor families, 22 unclassified non-coding RNAs, and 3 novel protein-coding genes significantly enriched in the regenerating tail. However, high levels of progenitor/stem cell markers were not observed in any region of the regenerating tail. Furthermore, we observed multiple tissue-type specific clusters of proliferating cells along the regenerating tail, not localized to the tail tip. These findings predict a different mechanism of regeneration in the lizard than the blastema model described in the salamander and the zebrafish, which are anamniote vertebrates. Thus, lizard tail regrowth involves the activation of conserved developmental and wound response pathways, which are potential targets for regenerative medical therapies.

  10. TRACKING STEM CELLS IN AN INHERENTLY REGENRATIVE ENVIRONMENT

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Foldager, Casper Bindzus; Hagensen, Mette

    2012-01-01

    of such therapies. The objective of this study was to non-invasively evaluate regeneration over time in a truly regenerative process, the regeneration of an axolotl limb, employing superparamagnetic iron oxide particles (SPIO) contrast agents for stem cell tracking in MRI. Materials and Methods: Amputation of one...... in conjugation with the transfection agent poly-L-lysin (PLL) was tested on cultures of axolotl blastema cells from 7 animals in vitro. PicoGreen-DNA quantification following 3 weeks of culturing was performed to quantify cell viability. MRI-tracking of SPIO labelled blastema cells in the regenerating limb of 5....... Results: SPIO labelling with neither VSOP-C200, Resovist nor Resovist/PLL had any significant effect on blastema cell viability in vitro. Labelled tissue was clearly detectable in vivo 49 days after amputation using MRI (Fig. 1) and a significant decline in signal intensity of labelled limbs versus sham...

  11. Impact of cycling cells and cell cycle regulation on Hydra regeneration.

    Science.gov (United States)

    Buzgariu, Wanda; Wenger, Yvan; Tcaciuc, Nina; Catunda-Lemos, Ana-Paula; Galliot, Brigitte

    2018-01-15

    Hydra tissues are made from three distinct populations of stem cells that continuously cycle and pause in G2 instead of G1. To characterize the role of cell proliferation after mid-gastric bisection, we have (i) used flow cytometry and classical markers to monitor cell cycle modulations, (ii) quantified the transcriptomic regulations of 202 genes associated with cell proliferation during head and foot regeneration, and (iii) compared the impact of anti-proliferative treatments on regeneration efficiency. We confirm two previously reported events: an early mitotic wave in head-regenerating tips, when few cell cycle genes are up-regulated, and an early-late wave of proliferation on the second day, preceded by the up-regulation of 17 cell cycle genes. These regulations appear more intense after mid-gastric bisection than after decapitation, suggesting a position-dependent regulation of cell proliferation during head regeneration. Hydroxyurea, which blocks S-phase progression, delays head regeneration when applied before but not after bisection. This result is consistent with the fact that the Hydra central region is enriched in G2-paused adult stem cells, poised to divide upon injury, thus forming a necessary constitutive pro-blastema. However a prolonged exposure to hydroxyurea does not block regeneration as cells can differentiate apical structures without traversing S-phase, and also escape in few days the hydroxyurea-induced S-phase blockade. Thus Hydra head regeneration, which is a fast event, is highly plastic, relying on large stocks of adult stem cells paused in G2 at amputation time, which immediately divide to proliferate and/or differentiate apical structures even when S-phase is blocked. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Localization and characterization of STRO-1 cells in the deer pedicle and regenerating antler.

    Directory of Open Access Journals (Sweden)

    Hans J Rolf

    2008-04-01

    Full Text Available The annual regeneration of deer antlers is a unique developmental event in mammals, which as a rule possess only a very limited capacity to regenerate lost appendages. Studying antler regeneration can therefore provide a deeper insight into the mechanisms that prevent limb regeneration in humans and other mammals, and, with regard to medical treatments, may possibly even show ways how to overcome these limitations. Traditionally, antler regeneration has been characterized as a process involving the formation of a blastema from de-differentiated cells. More recently it has, however, been hypothesized that antler regeneration is a stem cell-based process. Thus far, direct evidence for the presence of stem cells in primary or regenerating antlers was lacking. Here we demonstrate the presence of cells positive for the mesenchymal stem cell marker STRO-1 in the chondrogenic growth zone and the perivascular tissue of the cartilaginous zone in primary and regenerating antlers as well as in the pedicle of fallow deer (Dama dama. In addition, cells positive for the stem cell/progenitor cell markers STRO-1, CD133 and CD271 (LNGFR were isolated from the growth zones of regenerating fallow deer antlers as well as the pedicle periosteum and cultivated for extended periods of time. We found evidence that STRO-1(+ cells isolated from the different locations are able to differentiate in vitro along the osteogenic and adipogenic lineages. Our results support the view that the annual process of antler regeneration might depend on the periodic activation of mesenchymal progenitor cells located in the pedicle periosteum. The findings of the present study indicate that not only limited tissue regeneration, but also extensive appendage regeneration in a postnatal mammal can occur as a stem cell-based process.

  13. Epigenetics and Shared Molecular Processes in the Regeneration of Complex Structures

    Directory of Open Access Journals (Sweden)

    Labib Rouhana

    2016-01-01

    Full Text Available The ability to regenerate complex structures is broadly represented in both plant and animal kingdoms. Although regenerative abilities vary significantly amongst metazoans, cumulative studies have identified cellular events that are broadly observed during regenerative events. For example, structural damage is recognized and wound healing initiated upon injury, which is followed by programmed cell death in the vicinity of damaged tissue and a burst in proliferation of progenitor cells. Sustained proliferation and localization of progenitor cells to site of injury give rise to an assembly of differentiating cells known as the regeneration blastema, which fosters the development of new tissue. Finally, preexisting tissue rearranges and integrates with newly differentiated cells to restore proportionality and function. While heterogeneity exists in the basic processes displayed during regenerative events in different species—most notably the cellular source contributing to formation of new tissue—activation of conserved molecular pathways is imperative for proper regulation of cells during regeneration. Perhaps the most fundamental of such molecular processes entails chromatin rearrangements, which prime large changes in gene expression required for differentiation and/or dedifferentiation of progenitor cells. This review provides an overview of known contributions to regenerative processes by noncoding RNAs and chromatin-modifying enzymes involved in epigenetic regulation.

  14. Regenerated silica gel as stationary phase on vacuum column chromatography to purify temulawak’s extracts

    International Nuclear Information System (INIS)

    Cahyono, Bambang; Maduwu, Ratna Dewi; Widayat,; Suzery, Meiny

    2015-01-01

    Commercial silica gel only used once by many researchers and affected high cost for purification process, also less support the green chemistry program. This research focused in regeneration silica gel that used purification of temulawak’s extracts (Curcuma xanthorrhiza Roxb) by vacuum column chromatography. Sample extracts (contains 10.1195±0.5971% of curcuminoids) was purified by vacuum column chromatography (pressure: 45 kPa, column: 100mm on length and 16mm on diameter). Ethanol 96% and acetone were compared as eluent. The amount of solvent and yield of curcuminoids used as indicator purification. The silica gel was regenerated with heating in 600°C for 8 hours The silica gels were analyzed by IR spectroscopy and X-ray diffraction. Furthermore, regenerated silica gel was used as the stationary phase in vacuum column chromatography under the same conditions with the previous purification. All the purification experiments were performed in three repetitions. Based on regression equation, y=0.132x+0.0011 (r 2 =0.9997) the yield of curcuminoids on purified products using ethanol as the eluent was improved 4.26% (to 14.3724±0.5749%) and by acetone was improved 3,03% (to 13.1450 ±0.6318%). The IR spectrum of both silica gel showed the same vibration profile and also there were three crystallinity peaks missing on its X-ray diffraction. Regenerated silica gel has the same performance with new silica gel in purification of temulawak’s extract: by ethanol has increased 4.08% (14.1947±0.7415%) and 2.93% (13.0447±0.4822) by acetone. In addition, all purification products showed similar TLC profiles. Purification using regenerated silica gel as the adsorbent on vacuum column chromatography has exactly same potential with the new silica gel

  15. Regenerated silica gel as stationary phase on vacuum column chromatography to purify temulawak’s extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cahyono, Bambang; Maduwu, Ratna Dewi; Widayat,; Suzery, Meiny [Organic Chemistry Laboratory, Departement of Chemistry, Diponegoro University Jln Prof. Soedharto SH, Tembalang, Semarang 50275, Indonesia Tel / Fax: (024) 7460058 (Indonesia)

    2015-12-29

    Commercial silica gel only used once by many researchers and affected high cost for purification process, also less support the green chemistry program. This research focused in regeneration silica gel that used purification of temulawak’s extracts (Curcuma xanthorrhiza Roxb) by vacuum column chromatography. Sample extracts (contains 10.1195±0.5971% of curcuminoids) was purified by vacuum column chromatography (pressure: 45 kPa, column: 100mm on length and 16mm on diameter). Ethanol 96% and acetone were compared as eluent. The amount of solvent and yield of curcuminoids used as indicator purification. The silica gel was regenerated with heating in 600°C for 8 hours The silica gels were analyzed by IR spectroscopy and X-ray diffraction. Furthermore, regenerated silica gel was used as the stationary phase in vacuum column chromatography under the same conditions with the previous purification. All the purification experiments were performed in three repetitions. Based on regression equation, y=0.132x+0.0011 (r{sup 2}=0.9997) the yield of curcuminoids on purified products using ethanol as the eluent was improved 4.26% (to 14.3724±0.5749%) and by acetone was improved 3,03% (to 13.1450 ±0.6318%). The IR spectrum of both silica gel showed the same vibration profile and also there were three crystallinity peaks missing on its X-ray diffraction. Regenerated silica gel has the same performance with new silica gel in purification of temulawak’s extract: by ethanol has increased 4.08% (14.1947±0.7415%) and 2.93% (13.0447±0.4822) by acetone. In addition, all purification products showed similar TLC profiles. Purification using regenerated silica gel as the adsorbent on vacuum column chromatography has exactly same potential with the new silica gel.

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

    Science.gov (United States)

    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

  17. Replacement of irradiated epidermis by migration of non-irradiated epidermis in the newt limb: the necessity of healthy epidermis for regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Lheureux, E. (Universite des Sciences et Techniques, Lille (France). Lab. de Morphogenese Animale)

    1983-08-01

    An X-irradiated newt limb is able to regenerate if non-irradiated skin as well as non-irradiated muscle is transplanted to the stump. In order to know whether limb regeneration required healthy epidermis or not, a triploid skin cuff was set at the most proximal level of an irradiated limb and muscle was transplanted to the level of the midforearm. The forearm was then amputated through the muscle graft. The result was a complete replacement of diploid irradiated epidermis by triploid epidermis, during the six weeks necessary for regeneration. Another investigation consisted of detecting a possible migration of non-irradiated triploid epidermis along an irradiated limb which had not been amputated. Healthy epidermis was found to migrate distally and replace irradiated epidermis in three weeks. Transplantation of a non-irradiated skin cuff or muscle to an irradiated limb stump was carried out on animals entirely irradiated to prevent any extra healthy epidermis cells from contaminating the regenerating limb epidermis. A regenerate developed from the skin graft but not from muscle graft. It is concluded that healthy epidermis must be present on the limb stump to permit the blastema to develop.

  18. Replacement of irradiated epidermis by migration of non-irradiated epidermis in the newt limb: the necessity of healthy epidermis for regeneration

    International Nuclear Information System (INIS)

    Lheureux, E.

    1983-01-01

    An X-irradiated newt limb is able to regenerate if non-irradiated skin as well as non-irradiated muscle is transplanted to the stump. In order to know whether limb regeneration required healthy epidermis or not, a triploid skin cuff was set at the most proximal level of an irradiated limb and muscle was transplanted to the level of the midforearm. The forearm was then amputated through the muscle graft. The result was a complete replacement of diploid irradiated epidermis by triploid epidermis, during the six weeks necessary for regeneration. Another investigation consisted of detecting a possible migration of non-irradiated triploid epidermis along an irradiated limb which had not been amputated. Healthy epidermis was found to migrate distally and replace irradiated epidermis in three weeks. Transplantation of a non-irradiated skin cuff or muscle to an irradiated limb stump was carried out on animals entirely irradiated to prevent any extra healthy epidermis cells from contaminating the regenerating limb epidermis. A regenerate developed from the skin graft but not from muscle graft. It is concluded that healthy epidermis must be present on the limb stump to permit the blastema to develop. (author)

  19. Identification of genes associated with regenerative success of Xenopus laevis hindlimbs

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    Barker Donna

    2008-06-01

    Full Text Available Abstract Background Epimorphic regeneration is the process by which complete regeneration of a complex structure such as a limb occurs through production of a proliferating blastema. This type of regeneration is rare among vertebrates but does occur in the African clawed frog Xenopus laevis, traditionally a model organism for the study of early development. Xenopus tadpoles can regenerate their tails, limb buds and the lens of the eye, although the ability of the latter two organs to regenerate diminishes with advancing developmental stage. Using a heat shock inducible transgene that remains silent unless activated, we have established a stable line of transgenic Xenopus (strain N1 in which the BMP inhibitor Noggin can be over-expressed at any time during development. Activation of this transgene blocks regeneration of the tail and limb of Xenopus tadpoles. Results In the current study, we have taken advantage of the N1 transgenic line to directly compare morphology and gene expression in same stage regenerating vs. BMP signalling deficient non-regenerating hindlimb buds. The wound epithelium of N1 transgenic hindlimb buds, which forms over the cut surface of the limb bud after amputation, does not transition normally into the distal thickened apical epithelial cap. Instead, a basement membrane and dermis form, indicative of mature skin. Furthermore, the underlying mesenchyme remains rounded and does not expand to form a cone shaped blastema, a normal feature of successful regeneration. Using Affymetrix Gene Chip analysis, we have identified genes linked to regenerative success downstream of BMP signalling, including the BMP inhibitor Gremlin and the stress protein Hsp60 (no blastema in zebrafish. Gene Ontology analysis showed that genes involved in embryonic development and growth are significantly over-represented in regenerating early hindlimb buds and that successful regeneration in the Xenopus hindlimb correlates with the induction of

  20. Utilization of d-PTFE Barriers for Post-Extraction Bone Regeneration in Preparation for Dental Implants.

    Science.gov (United States)

    Greenstein, Gary; Carpentieri, Joseph R

    2015-01-01

    Guided bone regeneration (GBR) can be used to restore a defective alveolar ridge after extractions before or in combination with implant placement. It may also be employed after extractions to reduce crestal bone resorption and maximize bone fill of sockets. Resorbable or nonresorbable barriers (eg, expanded polytetrafluoroethylene [e-PTFE]) can be used when performing GBR procedures, but they need to be completely submerged to attain optimal results. Dense polytetrafluoroethylene (d-PTFE) is a type of nonresorbable barrier that circumvents the necessity to attain primary closure after placement of bone grafts, thereby reducing patient morbidity. This article addresses topics pertaining to d-PTFE utilization, including characteristics and advantages of d-PTFE barriers, time needed for osteoid tissue to become impervious to penetration by flap connective tissue, relevant clinical studies, and limitations of available data. Clinical photographs and radiographs of successfully treated cases are presented to illustrate the efficacy of d-PTFE barriers in regenerating defective bony plates after extractions.

  1. Blastema cells derived from New Zealand white rabbit's pinna carry stemness properties as shown by differentiation into insulin producing, neural, and osteogenic lineages representing three embryonic germ layers.

    Science.gov (United States)

    Saeinasab, Morvarid; Matin, Maryam M; Rassouli, Fatemeh B; Bahrami, Ahmad Reza

    2016-05-01

    Stem cells (SCs) are known as undifferentiated cells with self-renewal and differentiation capacities. Regeneration is a phenomenon that occurs in a limited number of animals after injury, during which blastema tissue is formed. It has been hypothesized that upon injury, the dedifferentiation of surrounding tissues leads into the appearance of cells with SC characteristics. In present study, stem-like cells (SLCs) were obtained from regenerating tissue of New Zealand white rabbit's pinna and their stemness properties were examined by their capacity to differentiate toward insulin producing cells (IPCs), as well as neural and osteogenic lineages. Differentiation was induced by culture of SLCs in defined medium, and cell fates were monitored by specific staining, RT-PCR and flow cytometry assays. Our results revealed that dithizone positive cells, which represent IPCs, and islet-like structures appeared 1 week after induction of SLCs, and this observation was confirmed by the elevated expression of Ins, Pax6 and Glut4 at mRNA level. Furthermore, SLCs were able to express neural markers as early as 1 week after retinoic acid treatment. Finally, SLCs were able to differentiate into osteogenic lineage, as confirmed by Alizarin Red S staining and RT-PCR studies. In conclusion, SLCs, which could successfully differentiate into cells derived from all three germ layers, can be considered as a valuable model to study developmental biology and regenerative medicine.

  2. Evaluating the complexation behavior and regeneration of boron selective glucaminium-based ionic liquids when used as extraction solvents

    International Nuclear Information System (INIS)

    Joshi, Manishkumar D.; Steyer, Daniel J.; Anderson, Jared L.

    2012-01-01

    Highlights: ► Glucaminium-based ILs exhibit high selectivity for boron species using DLLME. ► The concentration of glucaminium-based IL affects type of boron complex formed. ► Use of 0.1 M HCl allows for regeneration of the IL solvent following extraction. ► Selectivity of the glucaminium-based ILs for boron species in seawater is similar to Milli-Q water. - Abstract: Glucaminium-based ionic liquids are a new class of solvents capable of extracting boron-species from water with high efficiency. The complexation behavior of these ILs with borate was thoroughly studied using 11 B NMR. Two different complexes, namely, monochelate complex and bischelate complex, were observed. 11 B NMR was used extensively to determine the formation constants for monochelate and bischelate complexes. The IL concentration was observed to have a significant effect on the IL–borate complexes. Using an in situ dispersive liquid–liquid microextraction (in situ DLLME) method, the extraction efficiency for boron species was increased dramatically when lithium bis[(trifluoromethyl)sulfonyl]imide (LiNTf 2 ) was used as the metathesis salt in an aqueous solution containing 0.1 M sodium chloride. IL regeneration after extraction was achieved using 0.1 M hydrochloric acid. The extraction efficiency of boron species was consistent when the IL was employed after three regeneration cycles. The selectivity of the IL for boron species in synthetic seawater samples was similar to performing the same extraction from Milli-Q water samples.

  3. Cell proliferation is necessary for the regeneration of oral structures in the anthozoan cnidarian Nematostella vectensis

    Directory of Open Access Journals (Sweden)

    Passamaneck Yale J

    2012-12-01

    Full Text Available Abstract Background The contribution of cell proliferation to regeneration varies greatly between different metazoan models. Planarians rely on pluripotent neoblasts and amphibian limb regeneration depends upon formation of a proliferative blastema, while regeneration in Hydra can occur in the absence of cell proliferation. Recently, the cnidarian Nematostella vectensis has shown potential as a model for studies of regeneration because of the ability to conduct comparative studies of patterning during embryonic development, asexual reproduction, and regeneration. The present study investigates the pattern of cell proliferation during the regeneration of oral structures and the role of cell proliferation in this process. Results In intact polyps, cell proliferation is observed in both ectodermal and endodermal tissues throughout the entire oral-aboral axis, including in the tentacles and physa. Following bisection, there is initially little change in proliferation at the wound site of the aboral fragment, however, beginning 18 to 24 hours after amputation there is a dramatic increase in cell proliferation at the wound site in the aboral fragment. This elevated level of proliferation is maintained throughout the course or regeneration of oral structures, including the tentacles, the mouth, and the pharynx. Treatments with the cell proliferation inhibitors hydroxyurea and nocodazole demonstrate that cell proliferation is indispensable for the regeneration of oral structures. Although inhibition of regeneration by nocodazole was generally irreversible, secondary amputation reinitiates cell proliferation and regeneration. Conclusions The study has found that high levels of cell proliferation characterize the regeneration of oral structures in Nematostella, and that this cell proliferation is necessary for the proper progression of regeneration. Thus, while cell proliferation contributes to regeneration of oral structures in both Nematostella and

  4. Dissecting the function of Cullin-RING ubiquitin ligase complex genes in planarian regeneration.

    Science.gov (United States)

    Strand, Nicholas S; Allen, John M; Ghulam, Mahjoobah; Taylor, Matthew R; Munday, Roma K; Carrillo, Melissa; Movsesyan, Artem; Zayas, Ricardo M

    2018-01-15

    The ubiquitin system plays a role in nearly every aspect of eukaryotic cell biology. The enzymes responsible for transferring ubiquitin onto specific substrates are the E3 ubiquitin ligases, a large and diverse family of proteins, for which biological roles and target substrates remain largely undefined. Studies using model organisms indicate that ubiquitin signaling mediates key steps in developmental processes and tissue regeneration. Here, we used the freshwater planarian, Schmidtea mediterranea, to investigate the role of Cullin-RING ubiquitin ligase (CRL) complexes in stem cell regulation during regeneration. We identified six S. mediterranea cullin genes, and used RNAi to uncover roles for homologs of Cullin-1, -3 and -4 in planarian regeneration. The cullin-1 RNAi phenotype included defects in blastema formation, organ regeneration, lesions, and lysis. To further investigate the function of cullin-1-mediated cellular processes in planarians, we examined genes encoding the adaptor protein Skp1 and F-box substrate-recognition proteins that are predicted to partner with Cullin-1. RNAi against skp1 resulted in phenotypes similar to cullin-1 RNAi, and an RNAi screen of the F-box genes identified 19 genes that recapitulated aspects of cullin-1 RNAi, including ones that in mammals are involved in stem cell regulation and cancer biology. Our data provides evidence that CRLs play discrete roles in regenerative processes and provide a platform to investigate how CRLs regulate stem cells in vivo. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Activation of Pax7-positive cells in a non-contractile tissue contributes to regeneration of myogenic tissues in the electric fish S. macrurus.

    Directory of Open Access Journals (Sweden)

    Christopher M Weber

    Full Text Available 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

  6. Peripheral Nerve Regeneration Following Crush Injury to Rat Peroneal Nerve by Aqueous Extract of Medicinal Mushroom Hericium erinaceus (Bull.: Fr Pers. (Aphyllophoromycetideae

    Directory of Open Access Journals (Sweden)

    Kah-Hui Wong

    2011-01-01

    Full Text Available Nerve crush injury is a well-established axonotmetic model in experimental regeneration studies to investigate the impact of various pharmacological treatments. Hericium erinaceus is a temperate mushroom but is now being cultivated in tropical Malaysia. In this study, we investigated the activity of aqueous extract of H. erinaceus fresh fruiting bodies in promoting functional recovery following an axonotmetic peroneal nerve injury in adult female Sprague-Dawley rats by daily oral administration. The aim was to investigate the possible use of this mushroom in the treatment of injured nerve. Functional recovery was assessed in behavioral experiment by walking track analysis. Peroneal functional index (PFI was determined before surgery and after surgery as rats showed signs of recovery. Histological examinations were performed on peroneal nerve by immunofluorescence staining and neuromuscular junction by combined silver-cholinesterase stain. Analysis of PFI indicated that return of hind limb function occurred earlier in rats of aqueous extract or mecobalamin (positive control group compared to negative control group. Regeneration of axons and reinnervation of motor endplates in extensor digitorum longus muscle in rats of aqueous extract or mecobalamin group developed better than in negative control group. These data suggest that daily oral administration of aqueous extract of H. erinaceus fresh fruiting bodies could promote the regeneration of injured rat peroneal nerve in the early stage of recovery.

  7. Peripheral Nerve Regeneration Following Crush Injury to Rat Peroneal Nerve by Aqueous Extract of Medicinal Mushroom Hericium erinaceus (Bull.: Fr) Pers. (Aphyllophoromycetideae)

    Science.gov (United States)

    Wong, Kah-Hui; Naidu, Murali; David, Pamela; Abdulla, Mahmood Ameen; Abdullah, Noorlidah; Kuppusamy, Umah Rani; Sabaratnam, Vikineswary

    2011-01-01

    Nerve crush injury is a well-established axonotmetic model in experimental regeneration studies to investigate the impact of various pharmacological treatments. Hericium erinaceus is a temperate mushroom but is now being cultivated in tropical Malaysia. In this study, we investigated the activity of aqueous extract of H. erinaceus fresh fruiting bodies in promoting functional recovery following an axonotmetic peroneal nerve injury in adult female Sprague-Dawley rats by daily oral administration. The aim was to investigate the possible use of this mushroom in the treatment of injured nerve. Functional recovery was assessed in behavioral experiment by walking track analysis. Peroneal functional index (PFI) was determined before surgery and after surgery as rats showed signs of recovery. Histological examinations were performed on peroneal nerve by immunofluorescence staining and neuromuscular junction by combined silver-cholinesterase stain. Analysis of PFI indicated that return of hind limb function occurred earlier in rats of aqueous extract or mecobalamin (positive control) group compared to negative control group. Regeneration of axons and reinnervation of motor endplates in extensor digitorum longus muscle in rats of aqueous extract or mecobalamin group developed better than in negative control group. These data suggest that daily oral administration of aqueous extract of H. erinaceus fresh fruiting bodies could promote the regeneration of injured rat peroneal nerve in the early stage of recovery. PMID:21941586

  8. Ectopic Fgf signaling induces the intercalary response in developing chicken limb buds.

    Science.gov (United States)

    Makanae, Aki; Satoh, Akira

    2018-01-01

    Intercalary pattern formation is an important regulatory step in amphibian limb regeneration. Amphibian limb regeneration is composed of multiple steps, including wounding, blastema formation, and intercalary pattern formation. Attempts have been made to transfer insights from regeneration-competent animals to regeneration-incompetent animalsat each step in the regeneration process. In the present study, we focused on the intercalary mechanism in chick limb buds. In amphibian limb regeneration, a proximodistal axis is organized as soon as a regenerating blastema is induced. Intermediate structures are subsequently induced (intercalated) between the established proximal and distal identities. Intercalary tissues are derived from proximal tissues. Fgf signaling mediates the intercalary response in amphibian limb regeneration. We attempted to transfer insights into intercalary regeneration from amphibian models to the chick limb bud. The zeugopodial part was dissected out, and the distal and proximal parts were conjunct at st. 24. Delivering ectopic Fgf2 + Fgf8 between the distal and proximal parts resulted in induction of zeugopodial elements. Examination of HoxA11 expression, apoptosis, and cell proliferation provides insights to compare with those in the intercalary mechanism of amphibian limb regeneration. Furthermore, the cellular contribution was investigated in both the chicken intercalary response and that of axolotl limb regeneration. We developed new insights into cellular contribution in amphibian intercalary regeneration, and found consistency between axolotl and chicken intercalary responses. Our findings demonstrate that the same principal of limb regeneration functions between regeneration-competent and -incompetent animals. In this context, we propose the feasibility of the induction of the regeneration response in amniotes.

  9. BMP-2 functions independently of SHH signaling and triggers cell condensation and apoptosis in regenerating axolotl limbs

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    Finnson Kenneth

    2010-02-01

    Full Text Available Abstract Background Axolotls have the unique ability, among vertebrates, to perfectly regenerate complex body parts, such as limbs, after amputation. In addition, axolotls pattern developing and regenerating autopods from the anterior to posterior axis instead of posterior to anterior like all tetrapods studied to date. Sonic hedgehog is important in establishing this anterior-posterior axis of limbs in all tetrapods including axolotls. Interestingly, its expression is conserved (to the posterior side of limb buds and blastemas in axolotl limbs as in other tetrapods. It has been suggested that BMP-2 may be the secondary mediator of sonic hedgehog, although there is mounting evidence to the contrary in mice. Since BMP-2 expression is on the anterior portion of developing and regenerating limbs prior to digit patterning, opposite to the expression of sonic hedgehog, we examined whether BMP-2 expression was dependent on sonic hedgehog signaling and whether it affects patterning of the autopod during regeneration. Results The expression of BMP-2 and SOX-9 in developing and regenerating axolotl limbs corresponded to the first digits forming in the anterior portion of the autopods. The inhibition of sonic hedgehog signaling with cyclopamine caused hypomorphic limbs (during development and regeneration but did not affect the expression of BMP-2 and SOX-9. Overexpression of BMP-2 in regenerating limbs caused a loss of digits. Overexpression of Noggin (BMP inhibitor in regenerating limbs also resulted in a loss of digits. Histological analysis indicated that the loss due to BMP-2 overexpression was the result of increased cell condensation and apoptosis while the loss caused by Noggin was due to a decrease in cell division. Conclusion The expression of BMP-2 and its target SOX-9 was independent of sonic hedgehog signaling in developing and regenerating limbs. Their expression correlated with chondrogenesis and the appearance of skeletal elements has

  10. The effect of tomato juices and bean sprout extracts on vitro shoot regeneration of Physalis angulata L.

    Science.gov (United States)

    Mastuti, Retno; Munawarti, Aminatun; Rosyidah, Mufidatur

    2017-11-01

    Physalis angulata L. (Ciplukan) which belongs to Solanaceae is an important medicinal plant. In vitro culture medium contains carbon source, inorganic substance, vitamins, and plant growth regulators. However, organic growth supplements have frequently been added to improve regeneration capability of explants. This study was conducted to observe the effect of tomato juices and extract bean sprout on shoot regeneration and multiplication of in vitro nodal explants. The explants were cultured on MS basal medium + 6-benzyl amino purine (BAP) 2 mg/L + indole-3-acetic acid (IAA) 0.05 mg/L with and without organic supplements. Tomato juices (T) 5, 7.5 and 10% or bean sprout extract (B) 1.25, 2.5, and 3.75% were added as natural organic supplements. Almost all explants have produced shoots one week after culture. After six weeks of culture maximum shoot number (12.5±3.9) was produced in medium MS + T5 while maximum shoot length (10.7 ± 0.7 cm) was obtained in medium MS + T 7.5. Medium T tends to produce more shoots than the medium B and medium control. This result indicates the potential of natural organic supplements for supporting Ciplukan propagation through in vitro culture.

  11. Lithium recycling and cathode material regeneration from acid leach liquor of spent lithium-ion battery via facile co-extraction and co-precipitation processes.

    Science.gov (United States)

    Yang, Yue; Xu, Shengming; He, Yinghe

    2017-06-01

    A novel process for extracting transition metals, recovering lithium and regenerating cathode materials based on facile co-extraction and co-precipitation processes has been developed. 100% manganese, 99% cobalt and 85% nickel are co-extracted and separated from lithium by D2EHPA in kerosene. Then, Li is recovered from the raffinate as Li 2 CO 3 with the purity of 99.2% by precipitation method. Finally, organic load phase is stripped with 0.5M H 2 SO 4 , and the cathode material LiNi 1/3 Co 1/3 Mn 1/3 O 2 is directly regenerated from stripping liquor without separating metal individually by co-precipitation method. The regenerative cathode material LiNi 1/3 Co 1/3 Mn 1/3 O 2 is miro spherical morphology without any impurities, which can meet with LiNi 1/3 Co 1/3 Mn 1/3 O 2 production standard of China and exhibits good electrochemical performance. Moreover, a waste battery management model is introduced to guarantee the material supply for spent battery recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Development and regeneration of the zebrafish maxillary barbel: a novel study system for vertebrate tissue growth and repair.

    Science.gov (United States)

    LeClair, Elizabeth E; Topczewski, Jacek

    2010-01-15

    Barbels are integumentary sense organs found in fishes, reptiles and amphibians. The zebrafish, Danio rerio, develops paired nasal and maxillary barbels approximately one month post fertilization. Small in diameter and optically clear, these adult appendages offer a window on the development, maintenance and function of multiple cell types including skin cells, neural-crest derived pigment cells, circulatory vessels, taste buds and sensory nerves. Importantly, barbels in other otophysan fishes (e.g., catfish) are known to regenerate; however, this capacity has not been tested in zebrafish. We describe the development of the maxillary barbel in a staged series of wild type and transgenic zebrafish using light microscopy, histology and immunohistochemistry. By imaging transgenic zebrafish containing fluorescently labeled endothelial cells (Tg(fli1a:EGFP)), we demonstrate that the barbel contains a long ( approximately 2-3 mm) closed-end vessel that we interpret as a large lymphatic. The identity of this vessel was further supported by live imaging of the barbel circulation, extending recent descriptions of the lymphatic system in zebrafish. The maxillary barbel can be induced to regenerate by proximal amputation. After more than 750 experimental surgeries in which approximately 85% of the barbel's length was removed, we find that wound healing is complete within hours, followed by blastema formation ( approximately 3 days), epithelial redifferentiation (3-5 days) and appendage elongation. Maximum regrowth occurs within 2 weeks of injury. Although superficially normal, the regenerates are shorter and thicker than the contralateral controls, have abnormally organized mesenchymal cells and extracellular matrix, and contain prominent connective tissue "stumps" at the plane of section--a mode of regeneration more typical of mammalian scarring than other zebrafish appendages. Finally, we show that the maxillary barbel can regenerate after repeated injury and also in

  13. Development and regeneration of the zebrafish maxillary barbel: a novel study system for vertebrate tissue growth and repair.

    Directory of Open Access Journals (Sweden)

    Elizabeth E LeClair

    2010-01-01

    Full Text Available Barbels are integumentary sense organs found in fishes, reptiles and amphibians. The zebrafish, Danio rerio, develops paired nasal and maxillary barbels approximately one month post fertilization. Small in diameter and optically clear, these adult appendages offer a window on the development, maintenance and function of multiple cell types including skin cells, neural-crest derived pigment cells, circulatory vessels, taste buds and sensory nerves. Importantly, barbels in other otophysan fishes (e.g., catfish are known to regenerate; however, this capacity has not been tested in zebrafish.We describe the development of the maxillary barbel in a staged series of wild type and transgenic zebrafish using light microscopy, histology and immunohistochemistry. By imaging transgenic zebrafish containing fluorescently labeled endothelial cells (Tg(fli1a:EGFP, we demonstrate that the barbel contains a long ( approximately 2-3 mm closed-end vessel that we interpret as a large lymphatic. The identity of this vessel was further supported by live imaging of the barbel circulation, extending recent descriptions of the lymphatic system in zebrafish. The maxillary barbel can be induced to regenerate by proximal amputation. After more than 750 experimental surgeries in which approximately 85% of the barbel's length was removed, we find that wound healing is complete within hours, followed by blastema formation ( approximately 3 days, epithelial redifferentiation (3-5 days and appendage elongation. Maximum regrowth occurs within 2 weeks of injury. Although superficially normal, the regenerates are shorter and thicker than the contralateral controls, have abnormally organized mesenchymal cells and extracellular matrix, and contain prominent connective tissue "stumps" at the plane of section--a mode of regeneration more typical of mammalian scarring than other zebrafish appendages. Finally, we show that the maxillary barbel can regenerate after repeated injury and

  14. Method of continuously regenerating decontaminating electrolytic solution

    International Nuclear Information System (INIS)

    Sasaki, Takashi; Kobayashi, Toshio; Wada, Koichi.

    1985-01-01

    Purpose: To continuously recover radioactive metal ions from the electrolytic solution used for the electrolytic decontamination of radioactive equipment and increased with the radioactive dose, as well as regenerate the electrolytic solution to a high concentration acid. Method: A liquid in an auxiliary tank is recycled to a cathode chamber containing water of an electro depositing regeneration tank to render pH = 2 by way of a pH controller and a pH electrode. The electrolytic solution in an electrolytic decontaminating tank is introduced by way of an injection pump to an auxiliary tank and, interlocking therewith, a regenerating solution is introduced from a regenerating solution extracting pump by way of a extraction pipeway to an electrolytic decontaminating tank. Meanwhile, electric current is supplied to the electrode to deposit radioactive metal ions dissolved in the cathode chamber on the capturing electrode. While on the other hand, anions are transferred by way of a partition wall to an anode chamber to regenerate the electrolytic solution to high concentration acid solution. While on the other hand, water is supplied by way of an electromagnetic valve interlocking with the level meter to maintain the level meter constant. This can decrease the generation of the liquid wastes and also reduce the amount of the radioactive secondary wastes. (Horiuchi, T.)

  15. Transgenesis in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Khattak, Shahryar; Tanaka, Elly M

    2015-01-01

    Transgenic animals have been indispensable in elucidating and deciphering mechanisms underlying various biological phenomena. In regeneration, transgenic animals expressing fluorescent protein genes have been crucial for identifying the source cells for regeneration and the mechanism of blastema formation. Animals are usually generated by manipulating their genome using various techniques at/in one cell embryo/fertilized egg stage. Here, we describe the generation of germline transgenic axolotls (Ambystoma mexicanum) using the I-SceI meganuclease and Tol2 transposase.

  16. [Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

    Science.gov (United States)

    Liang, Hang; Deng, Xiangyu; Shao, Zengwu

    2017-10-01

    To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

  17. Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

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    M. Jesus Sanchez-Montero

    2018-01-01

    Full Text Available The properties of supercritical CO2 (SCCO2 and supercritical water (SCW turn them into fluids with a great ability to remove organic adsorbates retained on solids. These properties were used herein to regenerate an activated carbon fiber (ACF saturated with a pollutant usually contained in wastewater and drinking water, phenol. Severe regeneration conditions, up to 225 bar and 400 °C, had to be employed in SCCO2 regeneration to break the strong interaction established between phenol and the ACF. Under suitable conditions (regeneration temperature, time, and pressure, and flow of SCCO2 the adsorption capacity of the exhausted ACF was completely recovered, and even slightly increased. Most of the retained phenol was removed by thermal desorption, but the extra percentage removed by extraction allowed SCCO2 regeneration to be significantly more efficient than the classical thermal regeneration methods. SCCO2 regeneration and SCW regeneration were also compared for the first time. The use of SCW slightly improved regeneration, although SCW pressure was thrice SCCO2 pressure. The pathways that controlled SCW regeneration were also investigated.

  18. Autologous dental pulp stem cells in periodontal regeneration: a case report.

    Science.gov (United States)

    Aimetti, Mario; Ferrarotti, Francesco; Cricenti, Luca; Mariani, Giulia Maria; Romano, Federica

    2014-01-01

    Histologic findings in animal models suggest that the application of dental pulp stem cells (DPSCs) may promote periodontal regeneration in infrabony defects. This case report describes the clinical and radiographic regenerative potential of autologous DPSCs in the treatment of human noncontained intraosseous defects. A chronic periodontitis patient with one vital third molar requiring extraction was surgically treated. The third molar was extracted and used as an autologous DPSCs source to regenerate the infrabony defect on the mandibular right second premolar. At the 1-year examination, the defect was completely filled with bonelike tissue as confirmed through the reentry procedure.

  19. Deactivation and regeneration of refinery catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    1979-08-01

    A discussion covers the mechanisms of catalyst aging, poisoning, coke deposition, and metals deposition; feedstock pretreatment to extend catalyst life; the effects of operating conditions; the effects of catalyst composition and structure on its stability; nonchemical deactivation processes; and methods of catalyst regeneration, including coke burn-off and solvent extraction.

  20. Antidiabetic Evaluation of Momordica charantia L Fruit Extracts

    Science.gov (United States)

    Tahira, S; Hussain, F

    2014-01-01

    To investigate hypoglycaemic, hypolipidaemic and pancreatic beta cell regeneration activities of Momordica charantia L fruits (MC). Alloxan-induced diabetic rabbits were treated with methanolic and ethanolic MC extract. Effects of plant extracts and the drug glibenclamide on serum glucose, lipid profile and pancreatic beta cell were determined after two weeks of treatment. Serum glucose and lipid profiles were assayed by kit methods. Pancreatic tissue histopathology was performed to study pancreatic beta cell regeneration. Momordica charantia extracts produced significant hypoglycaemic effects (p Momordica charantia supplementations were unable to normalize glucose and lipid profiles. Glibenclamide, a standard drug, not only lowered hyperglycaemia and hyperlipidaemia but also restored the normal levels. Regeneration of pancreatic beta cells by MC extracts was minimal, with fractional improvement produced by glibenclamide. The most significant finding of the present study was a 28% reduction in hyperglycaemia by MC ethanol extracts. To determine reliable antidiabetic potentials of MC, identification of the relevant antidiabetic components and underlying mechanisms is warranted. PMID:25429471

  1. Escalated regeneration in sciatic nerve crush injury by the combined therapy of human amniotic fluid mesenchymal stem cells and fermented soybean extracts, Natto.

    Science.gov (United States)

    Pan, Hung-Chuan; Yang, Dar-Yu; Ho, Shu-Peng; Sheu, Meei-Ling; Chen, Chung-Jung; Hwang, Shiaw-Min; Chang, Ming-Hong; Cheng, Fu-Chou

    2009-08-23

    Attenuation of inflammatory cell deposits and associated cytokines prevented the apoptosis of transplanted stem cells in a sciatic nerve crush injury model. Suppression of inflammatory cytokines by fermented soybean extracts (Natto) was also beneficial to nerve regeneration. In this study, the effect of Natto on transplanted human amniotic fluid mesenchymal stem cells (AFS) was evaluated. Peripheral nerve injury was induced in SD rats by crushing a sciatic nerve using a vessel clamp. Animals were categorized into four groups: Group I: no treatment; Group II: fed with Natto (16 mg/day for 7 consecutive days); Group III: AFS embedded in fibrin glue; Group IV: Combination of group II and III therapy. Transplanted AFS and Schwann cell apoptosis, inflammatory cell deposits and associated cytokines, motor function, and nerve regeneration were evaluated 7 or 28 days after injury. The deterioration of neurological function was attenuated by AFS, Natto, or the combined therapy. The combined therapy caused the most significantly beneficial effects. Administration of Natto suppressed the inflammatory responses and correlated with decreased AFS and Schwann cell apoptosis. The decreased AFS apoptosis was in line with neurological improvement such as expression of early regeneration marker of neurofilament and late markers of S-100 and decreased vacuole formation. Administration of either AFS, or Natto, or combined therapy augmented the nerve regeneration. In conclusion, administration of Natto may rescue the AFS and Schwann cells from apoptosis by suppressing the macrophage deposits, associated inflammatory cytokines, and fibrin deposits.

  2. Escalated regeneration in sciatic nerve crush injury by the combined therapy of human amniotic fluid mesenchymal stem cells and fermented soybean extracts, Natto

    Directory of Open Access Journals (Sweden)

    Pan Hung-Chuan

    2009-08-01

    Full Text Available Abstract Attenuation of inflammatory cell deposits and associated cytokines prevented the apoptosis of transplanted stem cells in a sciatic nerve crush injury model. Suppression of inflammatory cytokines by fermented soybean extracts (Natto was also beneficial to nerve regeneration. In this study, the effect of Natto on transplanted human amniotic fluid mesenchymal stem cells (AFS was evaluated. Peripheral nerve injury was induced in SD rats by crushing a sciatic nerve using a vessel clamp. Animals were categorized into four groups: Group I: no treatment; Group II: fed with Natto (16 mg/day for 7 consecutive days; Group III: AFS embedded in fibrin glue; Group IV: Combination of group II and III therapy. Transplanted AFS and Schwann cell apoptosis, inflammatory cell deposits and associated cytokines, motor function, and nerve regeneration were evaluated 7 or 28 days after injury. The deterioration of neurological function was attenuated by AFS, Natto, or the combined therapy. The combined therapy caused the most significantly beneficial effects. Administration of Natto suppressed the inflammatory responses and correlated with decreased AFS and Schwann cell apoptosis. The decreased AFS apoptosis was in line with neurological improvement such as expression of early regeneration marker of neurofilament and late markers of S-100 and decreased vacuole formation. Administration of either AFS, or Natto, or combined therapy augmented the nerve regeneration. In conclusion, administration of Natto may rescue the AFS and Schwann cells from apoptosis by suppressing the macrophage deposits, associated inflammatory cytokines, and fibrin deposits.

  3. Local myogenic pulp-derived cell injection enhances craniofacial muscle regeneration in vivo.

    Science.gov (United States)

    Jung, J E; Song, M J; Shin, S; Choi, Y J; Kim, K H; Chung, C J

    2017-02-01

    To enhance myogenic differentiation in pulp cells isolated from extracted premolars by epigenetic modification using a DNA demethylation agent, 5-aza-2'-deoxycytidine (5-Aza), and to evaluate the potent stimulatory effect of 5-Aza-treated pulp cell injection for craniofacial muscle regeneration in vivo. Pulp cells were isolated from premolars extracted for orthodontic purposes from four adults (age range, 18-22.1 years). Levels of myogenic differentiation and functional contraction response in vitro were compared between pulp cells with or without pre-treatment of 5-Aza. Changes in muscle regeneration in response to green fluorescent protein (GFP)-labelled myogenic pulp cell injection in vivo were evaluated using a cardiotoxin (CTX)-induced muscle injury model of the gastrocnemius as well as the masseter muscle in mice. Pre-treatment of 5-Aza in pulp cells stimulated myotube formation, myogenic differentiation in terms of desmin and myogenin expression, and the level of collagen gel contraction. The local injection of 5-Aza pre-treated myogenic pulp cells was engrafted into the host tissue and indicated signs of enhanced muscle regeneration in both the gastrocnemius and the masseter muscles. The epigenetic modification of pulp cells from extracted premolars and the local injection of myogenic pulp cells may stimulate craniofacial muscles regeneration in vivo. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Morphological Evaluation of Shoots Regenerated from Hygromycin-Resistant Rice Callus (cv IACuba-28

    Directory of Open Access Journals (Sweden)

    Maylin Pérez Bernal

    2007-01-01

    Full Text Available An evaluation system based on the morphological characteristics of regenerated hygromycin-resistant rice callus shoots was established for correlating such characteristics with shoot viability on hygromycin. Embryogenic rice calli were transformed by Agrobacterium tumefaciens (EHA105/ pCAMBIA1300, containing the hygromycin-phosphotransferase gene as selection marker. After two weeks on selection medium, hygromycin-resistant calli were transferred to regeneration medium. Regenerated shoots were extracted every 5 days (over a 30-day period and classified into three classes according to their morphological structure: class I: vigorous shoot having typical bipolar structure; class II: shoot having small root compared to apical length, or shoot without roots; class III: shoots having an abnormal appearance, such as malformed leaves or albinism. Individualised shoots were transferred to MS medium containing hygromycin for evaluating their resistance to antibiotics. A relationship was observed between regenerated shoots’ morphological characteristics and the percentage of shoots’ viability on hygromycin. Class I prevailed at early shoot extraction and was the most resistant to hygromycin. Drastic class I reduction was found with later shoot extraction, whilst classes II and III became increased. Likewise, shoot viability became radically reduced on MS medium containing hygromycin. This result might be applied for improving efficiency regarding obtaining transgenic rice plants, taking into account the best time for obtaining high percentages of hygromycin-resistant shoots having the best morphological characteristics.

  5. Visualisation of axolotl blastema cells and pig endothelial progenitor cells using very small super paramagnetic iron oxide particles in MRI: A technique with applications for non invasive visualisation of regenerative processes

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Kjær, N.B.; Bek, Maria

    oxide particles (VSOP) in animal cells enable non invasive cell tracking using magnetic resonance imaging (MRI) and can prove useful, when visualising regenerative processes. This study examines the possibility of labelling limited numbers of axolotl blastema cells (aBC) and pig endothelial progenitor...... implanted in live axolotl tail and dead porcine heart, respectively. Cellular iron uptake was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Results: T2*-weighted 2D gradient-echo sequences on samples of 10˄5 cells yielded at significant linear correlations between...

  6. Serenoa repens extracts promote hair regeneration and repair of hair loss mouse models by activating TGF-β and mitochondrial signaling pathway.

    Science.gov (United States)

    Zhu, H-L; Gao, Y-H; Yang, J-Q; Li, J-B; Gao, J

    2018-06-01

    Plenty of plant extracts have been used for treating hair loss. This study aims to investigate the effects of liposterolic extracts of Serenoa repens (LSESr) on hair cell growth and regeneration of hair, and clarify the associated mechanisms. Human keratinocyte cells (HACAT) were cultured, incubated with dihydrotestosterone (DHT) and treated with LSESr. Cell viability was examined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H- tetrazolium bromide (MTT) assay. Hair loss C57BL/6 mouse model was established by inducing with DHT. Hair growth, density, and thickness were evaluated. Back skin samples were collected and stained with hematoxylin and eosin (HE) assay. B-cell lymphoma-2 (Bcl-2), Bcl-2 associated protein X (Bax), cleaved caspase 3 and transforming growth factor β2 (TGF-β2) were examined using Western blot assay. LSESr treatment significantly increased HACAT cell viabilities compared to DHT-only treated cells (p<0.05). LSESr treatment post injection of DHT significantly converted skin color from pink to gray and increased hair density, weight and thickness compared to DHT-only treated mice (p<0.05). LSESr treatment significantly triggered follicle growth and decreased inflammatory response. LSESr treatment significantly decreased TGF-β2 and cleaved caspase 3 expression of hair loss mouse models compared to that of DHT treated mice (p<0.05). LSESr treatment significantly enhanced Bcl-2 expression and reduced Bax expression compared to that of DHT treated mice (p<0.05). Meanwhile, effects of LSESr were substantial even achieving to the potential of finasteride. LSESr promoted the hair regeneration and repair of hair loss mouse models by activating TGF-β signaling and mitochondrial signaling pathway.

  7. Cryogenic regenerators

    International Nuclear Information System (INIS)

    Kush, P.; Joshi, S.C.; Thirumaleshwar, M.

    1986-01-01

    Importance of regenerators in cryogenic refrigerators is highlighted. Design aspects of regenerator are reviewed and the factors involved in the selection of regenerator material are enumerated. Various methods used to calculate the heat transfer coefficient and regenerator effectiveness are mentioned. Variation of effectiveness with various parameters is calculated by a computer programme using the ideal, Ackermann and Tipler formulae. Results are presented in graphical form. Listing of the computer programme is given in the Appendix. (author)

  8. Nerve signaling regulates basal keratinocyte proliferation in the blastema apical epithelial cap in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Bryant, Susan V; Gardiner, David M

    2012-06-15

    The ability of adult vertebrates to repair tissue damage is widespread and impressive; however, the ability to regenerate structurally complex organs such as the limb is limited largely to the salamanders. The fact that most of the tissues of the limb can regenerate has led investigators to question and identify the barriers to organ regeneration. From studies in the salamander, it is known that one of the earliest steps required for successful regeneration involves signaling between nerves and the wound epithelium/apical epithelial cap (AEC). In this study we confirm an earlier report that the keratinocytes of the AEC acquire their function coincident with exiting the cell cycle. We have discovered that this unique, coordinated behavior is regulated by nerve signaling and is associated with the presence of gap junctions between the basal keratinocytes of the AEC. Disruption of nerve signaling results in a loss of gap junction protein, the reentry of the cells into the cell cycle, and regenerative failure. Finally, coordinated exit from the cell cycle appears to be a conserved behavior of populations of cells that function as signaling centers during both development and regeneration. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. The Effect of the Uncariae Ramulus et Uncus on the Regeneration Following CNS Injury

    Directory of Open Access Journals (Sweden)

    Lee Jin-Goo

    2009-03-01

    Full Text Available Objective : Following central nervous system(CNS injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, gliosis. Also myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates with up-regulation of GFAP and CD81, and eventually becomes physical and mechanical barrier to axonal regeneration. MAG is one of several endogenous axon regeneration inhibitors that limit recovery from CNS injury and disease. It was reported that molecules that block such inhibitors enhanced axon regeneration and functional recovery. Recently it was reported that treatment with anti-CD81 antibodies enhanced functional recovery in the rat with spinal cord injury. So in this current study, the author investigated the effect of the water extract of Uncariae Ramulus et Uncus on the regulation of CD81, GFAP and MAG that increase when gliosis occurs. Methods : MTT assay was performed to examine cell viability, and cell-based ELISA, western blot and PCR were used to detect the expression of CD81, GFAP and MAG. Then also immunohistochemistry was performed to confirm in vivo. Results : Water extract of Uncariae Ramulus et Uncus showed relatively high cell viability at the concentration of 0.05%, 0.1% and 0.5%. The expression of CD81, GFAP and MAG in astrocytes was decreased after the administration of Uncariae Ramulus et Uncus water extract. These results was confirmed in the brain sections following cortical stab injury by immunohistochemistry. Conclusion : The authors observed that Uncariae Ramulus et Uncus significantly down-regulates the expression of CD81, GFAP and MAG. These results suggest that Uncariae Ramulus et Uncus can be a candidate to regenerate CNS injury.

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

    Science.gov (United States)

    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

  11. Regeneration

    Science.gov (United States)

    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...

  12. Regeneration complexities of Pinus gerardiana in dry temperate forests of Indian Himalaya.

    Science.gov (United States)

    Kumar, Raj; Shamet, G S; Mehta, Harsh; Alam, N M; Kaushal, Rajesh; Chaturvedi, O P; Sharma, Navneet; Khaki, B A; Gupta, Dinesh

    2016-04-01

    Pinus gerardiana is considered an important species in dry temperate forests of North-Western Indian Himalaya because of its influence on ecological processes and economic dependence of local people in the region. But, large numbers of biotic and abiotic factors have affected P. gerardiana in these forests; hence, there is a crucial need to understand the regeneration dynamics of this tree species. The present investigation was conducted in P. gerardiana forests to understand vegetation pattern and regeneration processes on different sites in the region. Statistical analysis was performed to know variability in growing stock and regeneration on sample plots, while correlation coefficients and regression models were developed to find the relationship between regeneration and site factors. The vegetation study showed dominance of P. gerardiana, which is followed by Cedrus deodara, Pinus wallichiana and Quercus ilex in the region. The growing stock of P. gerardiana showed steep increasing and then steadily declining trend from lower to higher diameter class. The distribution of seedling, sapling, pole and trees was not uniform at different sites and less number of plots in each site were observed to have effective conditions for continuous regeneration, but mostly showed extremely limited regeneration. Regeneration success ranging from 8.44 to 15.93 % was recorded in different sites of the region, which suggests that in different sites regeneration success is influenced by collection of cone for extracting seed, grazing/browsing and physico-chemical properties of soil. Regeneration success showed significant correlation and relationship with most of abiotic and biotic factors. The regeneration success is lower than the requirement of sustainable forest, but varies widely among sites in dry temperate forests of Himalaya. More forest surveys are required to understand the conditions necessary for greater success of P. gerardiana in the region.

  13. Ex vivo generation of a functional and regenerative wound epithelium from axolotl (Ambystoma mexicanum) skin.

    Science.gov (United States)

    Ferris, Donald R; Satoh, Akira; Mandefro, Berhan; Cummings, Gillian M; Gardiner, David M; Rugg, Elizabeth L

    2010-10-01

    Urodele amphibians (salamanders) are unique among adult vertebrates in their ability to regenerate structurally complete and fully functional limbs. Regeneration is a stepwise process that requires interactions between keratinocytes, nerves and fibroblasts. The formation of a wound epithelium covering the amputation site is an early and necessary event in the process but the molecular mechanisms that underlie the role of the wound epithelium in regeneration remain unclear. We have developed an ex vivo model that recapitulates many features of in vivo wound healing. The model comprises a circular explant of axolotl (Ambystoma mexicanum) limb skin with a central circular, full thickness wound. Re-epithelialization of the wound area is rapid (typically <11 h) and is dependent on metalloproteinase activity. The ex vivo wound epithelium is viable, responds to neuronal signals and is able to participate in ectopic blastema formation and limb regeneration. This ex vivo model provides a reproducible and tractable system in which to study the cellular and molecular events that underlie wound healing and regeneration. © 2010 The Authors. Journal compilation © 2010 Japanese Society of Developmental Biologists.

  14. Bioactive Scaffolds for Regeneration of Cartilage and Subchondral Bone Interface

    Science.gov (United States)

    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

  15. The investigation of HTGR fuel regeneration process

    Energy Technology Data Exchange (ETDEWEB)

    Lazarev, L N; Bertina, L E; Popik, V P; Isakov, V P; Alkhimov, N B; Pokhitonov, Yu A

    1985-07-01

    The aim of this report is the investigation of HTGR fuel regeneration. The operation in the technologic scheme of uranium extraction from fuel depleted elements is separation of fuel from graphite. Available methods of graphite matrix destruction are: mechanical destruction, chemical destruction, and burning. Mechanical destruction is done in combination with leaching or chlorination. Methods of chemical destruction of graphite matrix are not sufficiently studied. Most of the investigations nowadays sre devoted to removal of graphite by burning.

  16. The investigation of HTGR fuel regeneration process

    International Nuclear Information System (INIS)

    Lazarev, L.N.; Bertina, L.E.; Popik, V.P.; Isakov, V.P.; Alkhimov, N.B.; Pokhitonov, Yu.A.

    1985-01-01

    The aim of this report is the investigation of HTGR fuel regeneration. The operation in the technologic scheme of uranium extraction from fuel depleted elements is separation of fuel from graphite. Available methods of graphite matrix destruction are: mechanical destruction, chemical destruction, and burning. Mechanical destruction is done in combination with leaching or chlorination. Methods of chemical destruction of graphite matrix are not sufficiently studied. Most of the investigations nowadays sre devoted to removal of graphite by burning

  17. Desulfurization sorbent regeneration

    Science.gov (United States)

    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.

  18. Regeneration performance of CO2-rich solvents by using membrane vacuum regeneration technology: Relationships between absorbent structure and regeneration efficiency

    International Nuclear Information System (INIS)

    Yan, Shuiping; Fang, Mengxiang; Wang, Zhen; Luo, Zhongyang

    2012-01-01

    Highlights: ► MVR may be viable to successfully use less valuable heat to replace high grade steam. ► Increasing OH and amine groups will increase the regeneration efficiency. ► Absorbents with a four carbon chain length will be more attractive to MVR. ► Amino acid salts will be more appropriate for MVR. ► HRM conducted at ambient pressure and low temperature is inferior to MVR. -- Abstract: In order to give a better understanding for the selection of suitable absorbents for the novel membrane vacuum regeneration technology (MVR) which has the potential to reduce CO 2 energy requirement by utilizing the waste heat or low-grade energy, an experimental study to determine the relationships between chemical structure and vacuum regeneration behavior of CO 2 absorbents at 70 °C and 10 kPa was performed. Eleven typical absorbents with different functional groups in their chemical structures were investigated in terms of vacuum regeneration efficiencies. Results showed that the regeneration efficiency decreased with an increase of number of activated hydrogen atom in amine group and decreased with the number of hydroxyl group. Especially, more attention should be paid to these alkanolamines with one hydrogen atom in amine group and two or more hydroxyl groups in the structures due to their better comprehensive performance in regeneration, absorbent loss and CO 2 absorption aspects. Increasing the carbon chain length and amine groups in the absorbent structure contributed to the improvement of regeneration performance and reduction of absorbent volatile loss. These absorbents with a four carbon chain length bonded at amine group might be more attractive to MVR. Furthermore, polyamines were superior to monoamines in terms of higher regeneration efficiencies and lower absorbent losses. Additionally, the individual effects of the potassium carboxylate group and hydroxymethylene group were also compared in this study. Results showed that amino acid salts were more

  19. Investigation into Regeneration Mechanism of Hydroalcoholic Lavender (Lavandula officianalis Extract through the Evaluation of NT3 Gene Expression after Sciatic Nerve Compression in Rats

    Directory of Open Access Journals (Sweden)

    Fereshteh Naderi Allaf

    2017-05-01

    Full Text Available Abstract Background: Retrograde transport to the alpha motoneurons causes spinal degeneration. The neurotrophic factor (NT3 increases the number of myelinated axons in the dorsal root, leads to differentiation and survival of sensory neurons, parasympathetic motoneurons and prevents cell death. Lavender is a plant in the family Lamiaceae which is reported to have antioxidant, antispasmodic, diuretic, anti-asthmatic, refrigerant, and antipyretic effects. This study examined NT3 gene expression changes after sciatic nerve compression in rats, in the presence of Lavandula officinalis extract. Materials and Methods: Lavender Soxhlet hydroalcoholic extraction was prepared. 36 male Wistar rats were randomly divided into 3 groups including control, compression and treatment (compression group + hydroalcoholic extract of Lavender injections 75mg/kg groups. In controls the muscle was opened without damage to gain access to the sciatic nerve. In compression and treatment groups, the sciatic nerve (right leg was compressed. The extract was injected intraperitoneally in two occasions. A biopsy was taken from the spinal cord segments L4-L6 on day 28, total RNA was extracted and cDNA was synthesized and NT3 gene expression changes were analyzed by ANOVA test by using SPSS software. Results: The results showed that NT3 gene expression had a significant reduction in compression group compared to the control group (p<0.001 and it had a significant increase in treatment group compared with the compression group (p<0.001. Conclusion: A significant increase in gene expression shows that Lavandula officinalis hydroalcoholic extract improves nerve regeneration via NT3 gene expression.

  20. Complement components of nerve regeneration conditioned fluid influence the microenvironment of nerve regeneration

    Directory of Open Access Journals (Sweden)

    Guang-shuai Li

    2016-01-01

    Full Text Available Nerve regeneration conditioned fluid is secreted by nerve stumps inside a nerve regeneration chamber. A better understanding of the proteinogram of nerve regeneration conditioned fluid can provide evidence for studying the role of the microenvironment in peripheral nerve regeneration. In this study, we used cylindrical silicone tubes as the nerve regeneration chamber model for the repair of injured rat sciatic nerve. Isobaric tags for relative and absolute quantitation proteomics technology and western blot analysis confirmed that there were more than 10 complement components (complement factor I, C1q-A, C1q-B, C2, C3, C4, C5, C7, C8ß and complement factor D in the nerve regeneration conditioned fluid and each varied at different time points. These findings suggest that all these complement components have a functional role in nerve regeneration.

  1. Network-Based Method for Identifying Co- Regeneration Genes in Bone, Dentin, Nerve and Vessel Tissues.

    Science.gov (United States)

    Chen, Lei; Pan, Hongying; Zhang, Yu-Hang; Feng, Kaiyan; Kong, XiangYin; Huang, Tao; Cai, Yu-Dong

    2017-10-02

    Bone and dental diseases are serious public health problems. Most current clinical treatments for these diseases can produce side effects. Regeneration is a promising therapy for bone and dental diseases, yielding natural tissue recovery with few side effects. Because soft tissues inside the bone and dentin are densely populated with nerves and vessels, the study of bone and dentin regeneration should also consider the co-regeneration of nerves and vessels. In this study, a network-based method to identify co-regeneration genes for bone, dentin, nerve and vessel was constructed based on an extensive network of protein-protein interactions. Three procedures were applied in the network-based method. The first procedure, searching, sought the shortest paths connecting regeneration genes of one tissue type with regeneration genes of other tissues, thereby extracting possible co-regeneration genes. The second procedure, testing, employed a permutation test to evaluate whether possible genes were false discoveries; these genes were excluded by the testing procedure. The last procedure, screening, employed two rules, the betweenness ratio rule and interaction score rule, to select the most essential genes. A total of seventeen genes were inferred by the method, which were deemed to contribute to co-regeneration of at least two tissues. All these seventeen genes were extensively discussed to validate the utility of the method.

  2. Liver regeneration

    NARCIS (Netherlands)

    Chamuleau, R. A.; Bosman, D. K.

    1988-01-01

    Despite great advances in analysing hemodynamic, morphological and biochemical changes during the process of liver regeneration, the exact (patho)physiological mechanism is still unknown. A short survey of literature is given of the kinetics of liver regeneration and the significance of different

  3. The Amount of Regenerated Heat Inside the Regenerator of a Stirling Engine

    Directory of Open Access Journals (Sweden)

    J. Škorpík

    2008-01-01

    Full Text Available The paper deals with analytical computing of the regenerated heat inside the regenerator of a Stirling engine. The total sum of the regenerated heat is constructed as a function of the crank angle in the case of Schmidt’s idealization. 

  4. Seed recovery and regeneration in coal-fired, open-cycle magnetohydrodynamic systems

    International Nuclear Information System (INIS)

    Sheth, A.C.; Jackson, D.M.; Attig, R.C.

    1986-01-01

    Coal-fired magnetohydrodynamic (MHD) power systems not only have high cycle efficiency, but they also have an inherent sulfur removal capability. The potassium compound uses as ''seed'' plays a dual role. It 1) increases the electrical conductivity of the plasma needed to produce power in the MHD electrical topping cycle, and 2) reacts with sulfur dioxide to form potassium sulfate, thereby eliminating most of the sulfur oxides from the gaseous effluent. For economical reasons, the spent seed must be recovered, desulfurized and recycled to the MHD power plant. This paper reviews some of the available experimental results and literature relating to SO 2 removal and seed recovery, and will also discuss several potential seed regeneration processes. Three methods of potassium extraction are discussed, i.e., hot aqueous digestion with CA(OH) 2 /NaOH, acid washing, and aqueous extraction. The selected candidate regeneration systems are discussed from the viewpoint of energy and process water requirements and environmental considerations such as waste discharges and emissions of gaseous, particulate and trace element pollutants

  5. Assessment of regeneration of bone in the extracted third molar sockets augmented using xenograft (CollaPlugTN Zimmer in comparison with the normal healing on the contralateral side

    Directory of Open Access Journals (Sweden)

    Murugan Ranganathan

    2017-01-01

    Full Text Available Introduction: Alveolar bone resorption is a significant clinical problem. Bone loss in third molar region following extraction or surgical removal not only leads to periodontal problems in second molar region but also it may lead to some serious problems like increased incidence of angle fractures. In order to reduce the risks following third molar surgery, the socket should be augmented with bone grafts. In recent days guided tissue regeneration is the most accepted and successful technique followed many authors and its efficacy has been proved. Materials and Methods: Based upon our clinical experience, the use of bio absorbable collagen wound dressing such as CollaPlugTN has achieved quick healing and more primary wound coverage. Amongst the graft materials collagen is preferable due to its high biocompatibility and hemostatic ability. This study was done to assess the regeneration of bone in the extracted third molar sockets using xenograft (CollaPlugTN-Zimmer which was compared with the normal healing on the contra lateral side. The assessment was done to analyze post-operative healing complications and to compare the bone density formed between control site and implant site radiologically. Conclusion: On this basis of this study, the use of collaplugTN appears to be beneficial to the patient in postoperative wound healing and also for better bone formation. The use of this material was advantageous because of its simplicity of application cost effectiveness and availability. There is enhanced wound healing and early bone formation.

  6. Assessment of Regeneration of Bone in the Extracted Third Molar Sockets Augmented Using Xenograft (CollaPlugTN Zimmer) in Comparison with the Normal Healing on the Contralateral Side.

    Science.gov (United States)

    Ranganathan, Murugan; Balaji, M; Krishnaraj, R; Narayanan, Vivek; Thangavelu, Annamalai

    2017-11-01

    Alveolar bone resorption is a significant clinical problem. Bone loss in third molar region following extraction or surgical removal not only leads to periodontal problems in second molar region but also it may lead to some serious problems like increased incidence of angle fractures. In order to reduce the risks following third molar surgery, the socket should be augmented with bone grafts. In recent days guided tissue regeneration is the most accepted and successful technique followed many authors and its efficacy has been proved. Based upon our clinical experience, the use of bio absorbable collagen wound dressing such as CollaPlug TN has achieved quick healing and more primary wound coverage. Amongst the graft materials collagen is preferable due to its high biocompatibility and hemostatic ability. This study was done to assess the regeneration of bone in the extracted third molar sockets using xenograft (CollaPlug TN -Zimmer) which was compared with the normal healing on the contra lateral side. The assessment was done to analyze post-operative healing complications and to compare the bone density formed between control site and implant site radiologically. On this basis of this study, the use of collaplugTN appears to be beneficial to the patient in postoperative wound healing and also for better bone formation. The use of this material was advantageous because of its simplicity of application cost effectiveness and availability. There is enhanced wound healing and early bone formation.

  7. The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities

    Science.gov (United States)

    Chen, Xiaoping; Song, Fengyu; Jhamb, Deepali; Li, Jiliang; Bottino, Marco C.; Palakal, Mathew J.; Stocum, David L.

    2015-01-01

    We tested the ability of the axolotl (Ambystoma mexicanum) fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS) scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process. PMID:26098852

  8. Inferring regulatory networks from experimental morphological phenotypes: a computational method reverse-engineers planarian regeneration.

    Directory of Open Access Journals (Sweden)

    Daniel Lobo

    2015-06-01

    Full Text Available Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method

  9. "We Was Regenerated Out": Regeneration, Recycling and Devaluing Communities

    Directory of Open Access Journals (Sweden)

    Luna Glucksberg

    2014-12-01

    Full Text Available This article looks at well documented processes of urban regeneration and community displacement in the inner-city through an innovative anthropological perspective focused on concepts of waste and value. Using the notion of symbolic devaluation of the working classes developed by Skeggs (1997; 2004, it traces their exclusion from recycling practices while at the same time the estates they live on are being regenerated. Raising questions about the parallels and contradictions between regeneration and recycling, it shows how symbolic devaluation of specifi c areas and their inhabitants are necessary precursors of the physical demolition and removal that characterize regeneration processes. Through an ethnographic approach, the deep connections between people and their waste, and people as waste, are exposed and questioned, showing how valuable middle class selves are produced through appropriate waste management procedures, i.e. individualized recycling, while inner-city, estate dwellers are remade into uncaring, unworthy citizens who cannot take part in this value-producing circuit.

  10. The Effect of Elephantopus scaber L. on Liver Regeneration after Partial Hepatectomy

    Directory of Open Access Journals (Sweden)

    Chin-Chuan Tsai

    2013-01-01

    Full Text Available Liver regeneration after partial hepatectomy (PHx is a physiological response for maintaining homeostasis. The aim of this study is to investigate effects of Elephantopus scaber L.- (ESL- induced liver regeneration on growth factors (HGF and IGF-1, cell cycle regulation, and apoptosis suppressed. In this study, we fed five Chinese medicinal herbs (1 g/kg/day, Codonopsis pilosula (CP, Dangshen, Salvia miltiorrhiza Bunge (SMB, Danshen,, Bupleurum kasi (BK, Chaihu, Elephantopus scaber L. (ESL, Teng-Khia-U, and Silymarin (Sm, 25 mg/kg for 7 days to male Spraue-Dawley rats. Then surgical 2/3 PHx was conducted and liver regeneration mechanisms were estimated on the following 24 hrs and 72 hrs. The activities of growth factors (HGF and IGF-I and cell cycle proteins were measured by Western blot and RT-PCR. Histological analysis and apoptosis were detected by H&E stain and TUNEL. The results showed that extraction of Elephantopus scaber L. (ESL and Silymarin (Sm, positive control were increased protein expression levels of HGF and IGF-1 which leads into cell cycle. These results suggest that the ESL plays a crucial role in cell cycle-induced liver regeneration and apoptosis. These results suggested that the ESL plays a crucial role in cell cycle-induced liver regeneration and suppressed hepatocytes apoptosis.

  11. Solvent extraction of noble metals by formazans

    International Nuclear Information System (INIS)

    Grote, M.; Hueppe, U.; Kettrup, A.

    1984-01-01

    The extraction properties of ion-pairs composed of quaternary ammonium cations and a sulphonated formazan were compared with those of an unsulphonated formazan, for various solvent media. In dichloromethane the combined system behaves as a 'coloured anion-exchanger', with displacement of the sulphonated formazan, whereas in toluene Pd(II) and Ag(I) are extracted as the metal formazan chelates from aqueous medium. The rates of extraction are remarkably higher than with the simple extractants. Because of the higher stability only the simple chelating extraction systems afford satisfactory separation of Pd(II) from excess of Pt(IV) and of Ag(I) from Cu(II). The extracted metals can be stripped and the extractant regenerated. (author)

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

    Science.gov (United States)

    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.

  13. Regeneration-associated macrophages: a novel approach to boost intrinsic regenerative capacity for axon regeneration

    Directory of Open Access Journals (Sweden)

    Min Jung Kwon

    2016-01-01

    Full Text Available Axons in central nervous system (CNS do not regenerate spontaneously after injuries such as stroke and traumatic spinal cord injury. Both intrinsic and extrinsic factors are responsible for the regeneration failure. Although intensive research efforts have been invested on extrinsic regeneration inhibitors, the extent to which glial inhibitors contribute to the regeneration failure in vivo still remains elusive. Recent experimental evidence has rekindled interests in intrinsic factors for the regulation of regeneration capacity in adult mammals. In this review, we propose that activating macrophages with pro-regenerative molecular signatures could be a novel approach for boosting intrinsic regenerative capacity of CNS neurons. Using a conditioning injury model in which regeneration of central branches of dorsal root ganglia sensory neurons is enhanced by a preceding injury to the peripheral branches, we have demonstrated that perineuronal macrophages surrounding dorsal root ganglia neurons are critically involved in the maintenance of enhanced regeneration capacity. Neuron-derived chemokine (C-C motif ligand 2 (CCL2 seems to mediate neuron-macrophage interactions conveying injury signals to perineuronal macrophages taking on a soley pro-regenerative phenotype, which we designate as regeneration-associated macrophages (RAMs. Manipulation of the CCL2 signaling could boost regeneration potential mimicking the conditioning injury, suggesting that the chemokine-mediated RAM activation could be utilized as a regenerative therapeutic strategy for CNS injuries.

  14. Bone Regeneration of Hydroxyapatite with Granular Form or Porous Scaffold in Canine Alveolar Sockets

    Science.gov (United States)

    JANG, SEOK JIN; KIM, SE EUN; HAN, TAE SUNG; SON, JUN SIK; KANG, SEONG SOO; CHOI, SEOK HWA

    2017-01-01

    This study was undertaken to assess bone regeneration using hydroxyapatite (HA). The primary focus was comparison of bone regeneration between granular HA (gHA) forms and porous HA (pHA) scaffold. The extracted canine alveolar sockets were divided with three groups: control, gHA and pHA. Osteogenic effect in the gHA and pHA groups showed bone-specific surface and bone mineral density to be significantly higher than that of the control group (psocket healing. For new bone formation during 8 weeks' post-implantation, HA with porous scaffold was superior to the granular form of HA. PMID:28438860

  15. Vegetative regeneration

    Science.gov (United States)

    George A. Schier; John R. Jones; Robert P. Winokur

    1985-01-01

    Aspen is noted for its ability to regenerate vegetatively by adventitious shoots or suckers that arise on its long lateral roots. It also produces sprouts from stumps and root collars; but they are not common. In a survey of regeneration after clearcutting mature aspen in Utah. Baker (1918b) found that 92% of the shoots originated from roots, 7% from root collars, and...

  16. Supercritical fluid regeneration of adsorbents

    Science.gov (United States)

    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.

  17. The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities.

    Directory of Open Access Journals (Sweden)

    Xiaoping Chen

    Full Text Available We tested the ability of the axolotl (Ambystoma mexicanum fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process.

  18. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub

    Science.gov (United States)

    Delerue, Florian; Gonzalez, Maya; Michalet, Richard; Pellerin, Sylvain; Augusto, Laurent

    2015-01-01

    The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation) due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development) as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se) and the physical world where the seedlings appear and develop (the regeneration habitat). PMID:26098877

  19. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub.

    Directory of Open Access Journals (Sweden)

    Florian Delerue

    Full Text Available The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se and the physical world where the seedlings appear and develop (the regeneration habitat.

  20. Effect of different in vitro culture extracts of black pepper (Piper nigrum L.) on toxic metabolites-producing strains.

    Science.gov (United States)

    Ahmad, Nisar; Abbasi, Bilal Haider; Fazal, Hina

    2016-03-01

    In the present study, the effect of different in vitro cultures (callus, in vitro shoots) and commercially available peppercorn extract was investigated for its activity against toxic metabolite-producing strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Candida albicans). These in vitro cultures were extracted with ethanol, hexane, and chloroform, and the antipathogenic activity was determined by well-diffusion method. Hexane extract of callus showed 22 mm zone of inhibition against B. cereus, 23 mm against S. aureus, while regenerated shoots and seeds have shown 24.3 and 26 mm zones of inhibition. The ethanolic extracts of regenerated Piper shoots have shown 25 mm activity against S. aureus, 21 mm against B. cereus, and 16 mm in the case of C. albicans in comparison with standard antibiotics. Peppercorn extracts in chloroform and ethanol had shown activities against B. cereus (23.6 mm) and B. subtilis (23.5 mm). During in vitro organogenesis and morphogenesis, cells and tissues produced a comparable phytochemicals profile like mother plant. Morphogenesis is critically controlled by the application of exogenous plant-growth regulators. Such addition alters the hormonal transduction pathways, and cells under in vitro conditions regenerate tissues, which are dependant on the physiological state of cells, and finally enhance the production of secondary metabolites. To the best of our knowledge, this is the first report to compare the antimicrobial potential of in vitro regenerated tissues and peppercorn with standard antibiotics. In conclusion, most of the extracts showed pronounced activities against all the pathogenic microbes. This is a preliminary work, and the minimum inhibitory concentration values needs to be further explored. Regenerated tissues of P. nigrum are a good source of biologically active metabolites for antimicrobial activities, and callus culture presented itself as

  1. Understanding Urban Regeneration in Turkey

    Science.gov (United States)

    Candas, E.; Flacke, J.; Yomralioglu, T.

    2016-06-01

    In Turkey, rapid population growth, informal settlements, and buildings and infrastructures vulnerable to natural hazards are seen as the most important problems of cities. Particularly disaster risk cannot be disregarded, as large parts of various cities are facing risks from earthquakes, floods and landslides and have experienced loss of lives in the recent past. Urban regeneration is an important planning tool implemented by local and central governments in order to reduce to disaster risk and to design livable environments for the citizens. The Law on the Regeneration of Areas under Disaster Risk, commonly known as the Urban Regeneration Law, was enacted in 2012 (Law No.6306, May 2012). The regulation on Implementation of Law No. 6306 explains the fundamental steps of the urban regeneration process. The relevant institutions furnished with various authorities such as expropriation, confiscation and changing the type and place of your property which makes urban regeneration projects very important in terms of property rights. Therefore, urban regeneration projects have to be transparent, comprehensible and acceptable for all actors in the projects. In order to understand the urban regeneration process, the legislation and projects of different municipalities in Istanbul have been analyzed. While some steps of it are spatial data demanding, others relate to land values. In this paper an overview of the urban regeneration history and activities in Turkey is given. Fundamental steps of the urban regeneration process are defined, and particularly spatial-data demanding steps are identified.

  2. A Rest Time-Based Prognostic Framework for State of Health Estimation of Lithium-Ion Batteries with Regeneration Phenomena

    Directory of Open Access Journals (Sweden)

    Taichun Qin

    2016-11-01

    Full Text Available State of health (SOH prognostics is significant for safe and reliable usage of lithium-ion batteries. To accurately predict regeneration phenomena and improve long-term prediction performance of battery SOH, this paper proposes a rest time-based prognostic framework (RTPF in which the beginning time interval of two adjacent cycles is adopted to reflect the rest time. In this framework, SOH values of regeneration cycles, the number of cycles in regeneration regions and global degradation trends are extracted from raw SOH time series and predicted respectively, and then the three sets of prediction results are integrated to calculate the final overall SOH prediction values. Regeneration phenomena can be found by support vector machine and hyperplane shift (SVM-HS model by detecting long beginning time intervals. Gaussian process (GP model is utilized to predict the global degradation trend, and nonlinear models are utilized to predict the regeneration amplitude and the cycle number of each regeneration region. The proposed framework is validated through experimental data from the degradation tests of lithium-ion batteries. The results demonstrate that both the global degradation trend and the regeneration phenomena of the testing batteries can be well predicted. Moreover, compared with the published methods, more accurate SOH prediction results can be obtained under this framework.

  3. An active magnetic regenerator device

    DEFF Research Database (Denmark)

    2015-01-01

    A rotating active magnetic regenerator (AMR) device comprising two or more regenerator beds, a magnet arrangement and a valve arrangement. The valve arrangement comprises a plurality of valve elements arranged substantially immovably with respect to the regenerator beds along a rotational direction...

  4. On marginal regeneration

    NARCIS (Netherlands)

    Stein, H.N.

    1991-01-01

    On applying the marginal regeneration concept to the drainage of free liquid films, problems are encountered: the films do not show a "neck" of minimum thickness at the film/border transition; and the causes of the direction dependence of the marginal regeneration are unclear. Both problems can be

  5. Transparent and Printable Regenerated Kenaf Cellulose/PVA Film

    Directory of Open Access Journals (Sweden)

    Hatika Kaco

    2014-02-01

    Full Text Available Cellulose was extracted from kenaf core powder by a series of bleaching processes and subsequently dissolved using an alkaline LiOH/urea solvent at low temperatures. The produced cellulose solution was mixed with polyvinyl alcohol (PVA with different ratios of cellulose/PVA and coagulated to produce regenerated transparent films. The films were then air dried to produce transparent film. The effects of PVA content on tensile index, transparency, pore size, and printability of the films were studied. A slight reduction of 7% on the tensile index of the film was observed when the content of PVA increased to 10%. Nevertheless, the addition of 10% of PVA increased the porosity of the regenerated cellulose/PVA film, while the transparency of the film increased by 10%. The films were color-printed using a laser printer and can be recycled, in which the printed ink can be removed easily from the films with higher amount of PVA content. In addition, the films can be reprinted repeatedly several times.

  6. Economic analysis of replacement regeneration and coppice regeneration in eucalyptus stands under risk conditions

    Directory of Open Access Journals (Sweden)

    Isabel Carolina de Lima Guedes

    2011-09-01

    Full Text Available Projects are by their very nature subject to conditions of uncertainty that obstruct the decision-making process. Uncertainties involving forestry projects are even greater, as they are combined with time of return on capital invested, being medium to long term. For successful forest planning, it is necessary to quantify uncertainties by converting them into risks. The decision on whether to adopt replacement regeneration or coppice regeneration in a forest stand is influenced by several factors, which include land availability for new forest crops, changes in project end use, oscillations in demand and technological advancement. This study analyzed the economic feasibility of replacement regeneration and coppice regeneration of eucalyptus stands, under deterministic and under risk conditions. Information was gathered about costs and revenues for charcoal production in order to structure the cash flow used in the economic analysis, adopting the Net Present Value method (VPL. Risk assessment was based on simulations running the Monte Carlo method. Results led to the following conclusions: replacement regeneration is economically viable, even if the future stand has the same productivity as the original stand; coppice regeneration is an economically viable option even if productivity is a mere 70% of the original stand (high-tree planted stand, the best risk-return ratio option is restocking the stand (replacement regeneration by one that is 20% more productive; the probabilistic analysis running the Monte Carlo method revealed that invariably there is economic viability for the various replacement and coppice regeneration options being studied, minimizing uncertainties and consequently increasing confidence in decision-making.

  7. Methodological approach for the evaluation of homologous bone graft use in post-extractive atrophic alveolar ridges

    Directory of Open Access Journals (Sweden)

    B. Musante

    2013-01-01

    Full Text Available The aim of this study is to investigate the in vivo efficacy of Puros® cancellous particulate allograft bone in the regeneration of post-extractive sites. Twelve molar or premolar sites were selected. Seven days after minimally invasive tooth extraction, Puros® cancellous particulate allografts were inserted into the elected sites. TC Cone-Beam investigation and at 4 months from surgery; bone height and width were evaluated. Five months after surgery, biopsy samples of the regenerated sites were taken and histologically analyzed to qualitatively evaluate bone regeneration. TC analysis showed, a mean bone gain of 4.1 mm in height and 2.02 mm in width. The histological analysis of the samples showed intense bone metabolic activity with active osteoblasts on the implant surface, at the level of the native bone-graft interface and in the grafted area. The radiographic and histological analyses demonstrate an optimal bonen regeneration, both in terms of quality and quantity using Puros®.

  8. Perfluorodecalin and bone regeneration

    Directory of Open Access Journals (Sweden)

    F Tamimi

    2013-01-01

    Full Text Available Perfluorodecalin (PFD is a chemically and biologically inert biomaterial and, as many perfluorocarbons, is also hydrophobic, radiopaque and has a high solute capacity for gases such as oxygen. In this article we have demonstrated, both in vitro and in vivo, that PFD may significantly enhance bone regeneration. Firstly, the potential benefit of PFD was demonstrated by prolonging the survival of bone marrow cells cultured in anaerobic conditions. These findings translated in vivo, where PFD incorporated into bone-marrow-loaded 3D-printed scaffolds substantially improved their capacity to regenerate bone. Secondly, in addition to biological applications, we have also shown that PFD improves the radiopacity of bone regeneration biomaterials, a key feature required for the visualisation of biomaterials during and after surgical implantation. Finally, we have shown how the extreme hydrophobicity of PFD enables the fabrication of highly cohesive self-setting injectable biomaterials for bone regeneration. In conclusion, perfluorocarbons would appear to be highly beneficial additives to a number of regenerative biomaterials, especially those for bone regeneration.

  9. Regenerating an Arsenic Removal Iron-Based Adsorptive ...

    Science.gov (United States)

    The replacement of exhausted, adsorptive media used to remove arsenic from drinking water accounts for approximately 80% of the total operational and maintenance (O/M) costs of this commonly used small system technology. The results of three, full scale system studies of an on-site media regeneration process (Part 1) showed it to be effective in stripping arsenic and other contaminants from the exhausted media. Part 2, of this two part paper, presents information on the performance of the regenerated media to remove arsenic through multiple regeneration cycles (3) and the approximate cost savings of regeneration over media replacement. The results of the studies indicate that regenerated media is very effective in removing arsenic and the regeneration cost is substantially less than the media replacement cost. On site regeneration, therefore, provides small systems with alternative to media replacement when removing arsenic from drinking water using adsorptive media technology. Part 2 of a two part paper on the performance of the regenerated media to remove arsenic through multiple regeneration cycles (3) and the approximate cost savings of regeneration over media replacement.

  10. Skeletal muscle regeneration is modulated by inflammation

    Directory of Open Access Journals (Sweden)

    Wenjun Yang

    2018-04-01

    Full Text Available Skeletal muscle regeneration is a complex process orchestrated by multiple steps. Recent findings indicate that inflammatory responses could play central roles in bridging initial muscle injury responses and timely muscle injury reparation. The various types of immune cells and cytokines have crucial roles in muscle regeneration process. In this review, we briefly summarise the functions of acute inflammation in muscle regeneration. The translational potential of this article: Immune system is closely relevant to the muscle regeneration. Understanding the mechanisms of inflammation in muscle regeneration is therefore critical for the development of effective regenerative, and therapeutic strategies in muscular disorders. This review provides information for muscle regeneration research regarding the effects of inflammation on muscle regeneration. Keywords: Chronic muscle disorders, Cytokines, Immune cells, Inflammation, Muscle regeneration, Muscle stem cells

  11. Functional hepatocellular regeneration measured by hepatobiliary scintigraphy, functional regeneration or functional hepatocytes?

    NARCIS (Netherlands)

    Olthof, Pim B.; Cieslak, Kasia P.; Bennink, Roelof J.; van Gulik, Thomas M.

    2016-01-01

    In a recent issue of this journal, Fernandes et al(1) reported on functional hepatocellular regeneration in elderly patients undergoing hepatectomy. They used (99m) Tc-mebrofinin HBS to quantify liver function before and after surgery and concluded that functional regeneration is already present at

  12. QPSK regeneration without active phase-locking

    DEFF Research Database (Denmark)

    Kjøller, Niels-Kristian; Da Ros, Francesco; Røge, Kasper Meldgaard

    2016-01-01

    QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal.......QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal....

  13. Biological regeneration of para-nitrophenol loaded activated carbon

    International Nuclear Information System (INIS)

    Durrani, M.A.Q.; Martin, R.J.

    1997-01-01

    Biological regeneration is one of several methods that may be used to restore the adsorptive capacity of exhausted granular activated carbon (GAC). This study deals with in-situ biological regeneration on a pilot scale. The principal objective of this research was to ascertain whether biological regeneration of GAC could occur under conditions typical of water treatment. The important parameters which may have the greatest impact on bio regeneration of a given adsorbate were studied. The research investigated the extent of bio regeneration for para-nitrophenol (PNP) of concentration 50 mg/L. Bio regeneration in the total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bio regeneration run. The prepared carbon was initially exhausted with an adsorbate; it was then bio regenerated for para-nitrophenol (PNP) of concentration 50 mg/L. Bio regeneration in he total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bio regeneration run. The prepared carbon was initially exhausted with an adsorbate; it was then bio regenerated with a mixed culture of bacteria, and lastly the carbon was re-saturated. In the totally exhausted GAC system, the bio regeneration was enhanced by increasing the during of regeneration for a fixed initial biomass content of the bioreactor. The bio regeneration efficiency of the totally exhausted (with PNP) GAC the empty bed contact time (EBCT) and the initial concentration of the substrate had a profound effect on the bio regeneration efficiency. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents. (author)

  14. Results from neutral kaon regeneration at high energies

    International Nuclear Information System (INIS)

    Hladky, J.

    1976-01-01

    Experimental neutral kaon regeneration results at Serpukhov energies up to 50 GeV are presented, including the coherent regeneration on hydrogen, deuterium and carbon regenerators and elastic regeneration on deuterium and carbon regenerators. (author)

  15. Regeneration of desiccants with solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, S.R.; Butts, C.L.; Lown, J.B.

    1985-01-01

    Saturated silica gel was regenerated with solar energy. This paper describes the experimental set-up for silica gel regeneration and data collection. The regenerated silica gel can be used to dry high moisture in-shell pecans.

  16. Sterilization of African Violet in the in Vitro Culture Using Synthesized Silver Nanoparticles by Two Plant Extracts

    Directory of Open Access Journals (Sweden)

    M. Solgi

    2015-12-01

    Full Text Available One of the major advantages of in vitro culture of African violet (Saintpaulha ionantha is production of new cultivars and propagation of their chimera which might not be propagated by the other methods. In this study, we tested the effects of silver nanoparticles on the sterilization rate (antifungal and antibacterial activity, regeneration and shoot formation of African violet "Pink Amiss" explants. These nanoparticles were synthesized from pomegranate peels and Damask rose petals extracts. We used a completely randomized design test with factorial arrangement to investigate various volumetric ratios of plant extracts to silver nitrate (1:20, 1:10, 1:5 and 1:1 on the culture contaminations. Using silver nanoparticles synthesized by the plant extracts, especially Damask rose petals extract resulted in no fungal and bacterial contamination in the African violet explants after 1 and 3 weeks as compared to the control, and silver nitrate (1mM. All tested concentrations of the silver nanoparticles significantly (P &le 0.05 controlled both bacterial and fungal contaminations. The 1:20 ratio of plant extracts to silver nitrate showed the best control. In addition, the highest regeneration (%52 and shoot regeneration (%38 was observed in this treatment. In conclusion, we suggest using silver nanoparticles synthesized by plant extracts for sterilization of in Vitro Culture for African Violet rather than using other chemicals such as silver nitrate.

  17. A numerical analysis of a reciprocating Active Magnetic Regenerator with a parallel-plate regenerator geometry

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank; Pryds, Nini; Smith, Anders

    2007-01-01

    We have developed a two-dimensional model of a reciprocating Active Magnetic Regenerator(AMR) with a regenerator made of parallel plates arranged in a stack configuration. The time dependent,two-dimensional model solves the Navier-Stokes equations for the heat transfer fluid and the coupled heat...... transfer equations for the regenerator and the fluid. The model is implemented using the Finite Element Method. The model can be used to study both transient and steady-state phenomena in the AMR for any ratio of regenerator to fluid heat capacity. Results on the AMR performance for different design...

  18. Regeneration mechanisms in Syllidae (Annelida)

    Science.gov (United States)

    Ribeiro, Rannyele P.

    2018-01-01

    Abstract Syllidae is one of the most species‐rich groups within Annelida, with a wide variety of reproductive modes and different regenerative processes. Syllids have striking ability to regenerate their body anteriorly and posteriorly, which in many species is redeployed during sexual (schizogamy) and asexual (fission) reproduction. This review summarizes the available data on regeneration in syllids, covering descriptions of regenerative mechanisms in different species as well as regeneration in relation to reproductive modes. Our survey shows that posterior regeneration is widely distributed in syllids, whereas anterior regeneration is limited in most of the species, excepting those reproducing by fission. The latter reproductive mode is well known for a few species belonging to Autolytinae, Eusyllinae, and Syllinae. Patterns of fission areas have been studied in these animals. Deviations of the regular regeneration pattern or aberrant forms such as bifurcated animals or individuals with multiple heads have been reported for several species. Some of these aberrations show a deviation of the bilateral symmetry and antero‐posterior axis, which, interestingly, can also be observed in the regular branching body pattern of some species of syllids. PMID:29721325

  19. Dendrite Injury Triggers DLK-Independent Regeneration

    Directory of Open Access Journals (Sweden)

    Michelle C. Stone

    2014-01-01

    Full Text Available Axon injury triggers regeneration through activation of a conserved kinase cascade, which includes the dual leucine zipper kinase (DLK. Although dendrites are damaged during stroke, traumatic brain injury, and seizure, it is not known whether mature neurons monitor dendrite injury and initiate regeneration. We probed the response to dendrite damage using model Drosophila neurons. Two larval neuron types regrew dendrites in distinct ways after all dendrites were removed. Dendrite regeneration was also triggered by injury in adults. Next, we tested whether dendrite injury was initiated with the same machinery as axon injury. Surprisingly, DLK, JNK, and fos were dispensable for dendrite regeneration. Moreover, this MAP kinase pathway was not activated by injury to dendrites. Thus, neurons respond to dendrite damage and initiate regeneration without using the conserved DLK cascade that triggers axon regeneration.

  20. Acoustic field modulation in regenerators

    Science.gov (United States)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  1. Synthetic Phage for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    So Young Yoo

    2014-01-01

    Full Text Available Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy.

  2. Neural stem cells promote nerve regeneration through IL12-induced Schwann cell differentiation.

    Science.gov (United States)

    Lee, Don-Ching; Chen, Jong-Hang; Hsu, Tai-Yu; Chang, Li-Hsun; Chang, Hsu; Chi, Ya-Hui; Chiu, Ing-Ming

    2017-03-01

    Regeneration of injured peripheral nerves is a slow, complicated process that could be improved by implantation of neural stem cells (NSCs) or nerve conduit. Implantation of NSCs along with conduits promotes the regeneration of damaged nerve, likely because (i) conduit supports and guides axonal growth from one nerve stump to the other, while preventing fibrous tissue ingrowth and retaining neurotrophic factors; and (ii) implanted NSCs differentiate into Schwann cells and maintain a growth factor enriched microenvironment, which promotes nerve regeneration. In this study, we identified IL12p80 (homodimer of IL12p40) in the cell extracts of implanted nerve conduit combined with NSCs by using protein antibody array and Western blotting. Levels of IL12p80 in these conduits are 1.6-fold higher than those in conduits without NSCs. In the sciatic nerve injury mouse model, implantation of NSCs combined with nerve conduit and IL12p80 improves motor recovery and increases the diameter up to 4.5-fold, at the medial site of the regenerated nerve. In vitro study further revealed that IL12p80 stimulates the Schwann cell differentiation of mouse NSCs through the phosphorylation of signal transducer and activator of transcription 3 (Stat3). These results suggest that IL12p80 can trigger Schwann cell differentiation of mouse NSCs through Stat3 phosphorylation and enhance the functional recovery and the diameter of regenerated nerves in a mouse sciatic nerve injury model. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    International Nuclear Information System (INIS)

    Kulyk, W.M.; Zalik, S.E.; Dimitrov, E.

    1987-01-01

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of [ 3 H]glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion

  4. Effect of the Characters of Chitosans Used and Regeneration Conditions on the Yield and Physicochemical Characteristics of Regenerated Products

    Directory of Open Access Journals (Sweden)

    Chu Hsi Hsu

    2015-04-01

    Full Text Available The objective of this study was to explore the effect of the character of chitosans used, and the regeneration conditions employed on, the yield and physicochemical characteristics of regenerated products. Different concentrations of acetic acid were used to dissolve chitosans of 61.7% and 94.9% degree of deacetylation (DD, and weight-average molecular weight (Mw of 176 and 97 kDa, respectively; they were then precipitated with an 8 N NaOH solution, followed by washing and neutral and freeze drying to get the regenerated products. Yields of regenerated products and their physicochemical properties, such as ash content, bulk density, Mw, polydispersity index (PDI, DD, and crystallinity were measured. A higher concentration of acetic acid used resulted in a higher yield. The purity of the regenerated product increased significantly, whereas the bulk density and crystallinity decreased significantly after regeneration. The regeneration process showed its merits of narrowing down the PDI of regenerated products. The DD and structure of chitosan was changed insignificantly after the regeneration process.

  5. New insight into regenerated air heat pump cycle

    International Nuclear Information System (INIS)

    Zhang, Chun-Lu; Yuan, Han; Cao, Xiang

    2015-01-01

    Regenerated air (reverse Brayton) cycle has unique potentials in heat pump applications compared to conventional vapor-compression cycles. To better understand the regenerated air heat pump cycle characteristics, a thermodynamic model with new equivalent parameters was developed in this paper. Equivalent temperature ratio and equivalent isentropic efficiency of expander were introduced to represent the effect of regenerator, which made the regenerated air cycle in the same mathematical expressions as the basic air cycle and created an easy way to prove some important features that regenerated air cycle inherits from the basic one. Moreover, we proved in theory that the regenerator does not always improve the air cycle efficiency. Larger temperature ratio and lower effectiveness of regenerator could make the regenerated air cycle even worse than the basic air cycle. Lastly, we found that only under certain conditions the cycle could get remarkable benefits from a well-sized regenerator. These results would enable further study of the regenerated air cycle from a different perspective. - Highlights: • A thermodynamic model for regenerated air heat pump cycle was developed. • Equivalent temperature ratio and equivalent expander efficiency were introduced. • We proved regenerated air cycle can make heating capacity in line with heating load. • We proved the regenerator does not always improve the air cycle efficiency.

  6. The combination use of platelet-rich fibrin and treated dentin matrix for tooth root regeneration by cell homing.

    Science.gov (United States)

    Ji, Baohui; Sheng, Lei; Chen, Gang; Guo, Shujuan; Xie, Li; Yang, Bo; Guo, Weihua; Tian, Weidong

    2015-01-01

    Endogenous regeneration through cell homing provides an alternative approach for tissue regeneration, except cell transplantation, especially considering clinical translation. However, tooth root regeneration through cell homing remains a provocative approach in need of intensive study. Both platelet-rich fibrin (PRF) and treated dentin matrix (TDM) are warehouses of various growth factors, which can promote cell homing. We hypothesized that endogenous stem cells are able to sense biological cues from PRF membrane and TDM, and contribute to the regeneration of tooth root, including soft and hard periodontal tissues. Therefore, the biological effects of canine PRF and TDM on periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMSCs) were evaluated respectively in vitro. Beagle dogs were used as orthotopic transplantation model. It was found that PRF significantly recruited and stimulated the proliferation of PDLSCs and BMSCs in vitro. Together, PRF and TDM induced cell differentiation by upregulating the mineralization-related gene expression of bone sialoprotein (BSP) and osteopotin (OPN) after 7 days coculture. In vivo, transplantation of autologous PRF and allogeneic TDM into fresh tooth extraction socket achieved successful root regeneration 3 months postsurgery, characterized by the regeneration of cementum and periodontal ligament (PDL)-like tissues with orientated fibers, indicative of functional restoration. The results suggest that tooth root connected to the alveolar bone by cementum-PDL complex can be regenerated through the implantation of PRF and TDM in a tooth socket microenvironment, probably by homing of BMSCs and PDLSCs. Furthermore, bioactive cues and inductive microenvironment are key factors for endogenous regeneration. This approach provides a tangible pathway toward clinical translation.

  7. Semiconductor devices for all-optical regeneration

    DEFF Research Database (Denmark)

    Öhman, Filip; Bischoff, Svend; Tromborg, Bjarne

    2003-01-01

    We review different implementations of semiconductor devices for all-optical regeneration. A general model will be presented for all-optical regeneration in fiber links, taking into consideration the trade-off between non-linearity and noise. Furthermore we discuss a novel regenerator type, based...

  8. Regeneration in natural and logged tropical rain forest : modelling seed dispersal and regeneration

    NARCIS (Netherlands)

    Ulft, Lambertus Henricus van

    2004-01-01

    Regeneration and disturbance are thought to play key roles in the maintenance of the high tree species diversity in tropical rain forests. Nevertheless, the earliest stages in the regeneration of tropical rain forest trees, from seed production to established seedlings, have received little

  9. Guide to Regeneration of Bottomland Hardwoods

    Science.gov (United States)

    Martha R. McKevlin

    1992-01-01

    This guide will help landowners, consulting foresters, and public service foresters regenerate bottomland hardwoods. It discusses (1) interpretation of site characteristics, (2) selection of species, and (3) selection of regeneration methods. A dichotomous key for selection of appropriate regeneration methods under various conditions is presented.

  10. Axonal regeneration in zebrafish spinal cord

    Science.gov (United States)

    Hui, Subhra Prakash

    2018-01-01

    Abstract In the present review we discuss two interrelated events—axonal damage and repair—known to occur after spinal cord injury (SCI) in the zebrafish. Adult zebrafish are capable of regenerating axonal tracts and can restore full functionality after SCI. Unlike fish, axon regeneration in the adult mammalian central nervous system is extremely limited. As a consequence of an injury there is very little repair of disengaged axons and therefore functional deficit persists after SCI in adult mammals. In contrast, peripheral nervous system axons readily regenerate following injury and hence allow functional recovery both in mammals and fish. A better mechanistic understanding of these three scenarios could provide a more comprehensive insight into the success or failure of axonal regeneration after SCI. This review summarizes the present understanding of the cellular and molecular basis of axonal regeneration, in both the peripheral nervous system and the central nervous system, and large scale gene expression analysis is used to focus on different events during regeneration. The discovery and identification of genes involved in zebrafish spinal cord regeneration and subsequent functional experimentation will provide more insight into the endogenous mechanism of myelination and remyelination. Furthermore, precise knowledge of the mechanism underlying the extraordinary axonal regeneration process in zebrafish will also allow us to unravel the potential therapeutic strategies to be implemented for enhancing regrowth and remyelination of axons in mammals. PMID:29721326

  11. Cell migration during heart regeneration in zebrafish.

    Science.gov (United States)

    Tahara, Naoyuki; Brush, Michael; Kawakami, Yasuhiko

    2016-07-01

    Zebrafish possess the remarkable ability to regenerate injured hearts as adults, which contrasts the very limited ability in mammals. Although very limited, mammalian hearts do in fact have measurable levels of cardiomyocyte regeneration. Therefore, elucidating mechanisms of zebrafish heart regeneration would provide information of naturally occurring regeneration to potentially apply to mammalian studies, in addition to addressing this biologically interesting phenomenon in itself. Studies over the past 13 years have identified processes and mechanisms of heart regeneration in zebrafish. After heart injury, pre-existing cardiomyocytes dedifferentiate, enter the cell cycle, and repair the injured myocardium. This process requires interaction with epicardial cells, endocardial cells, and vascular endothelial cells. Epicardial cells envelope the heart, while endocardial cells make up the inner lining of the heart. They provide paracrine signals to cardiomyocytes to regenerate the injured myocardium, which is vascularized during heart regeneration. In addition, accumulating results suggest that local migration of these major cardiac cell types have roles in heart regeneration. In this review, we summarize the characteristics of various heart injury methods used in the research community and regeneration of the major cardiac cell types. Then, we discuss local migration of these cardiac cell types and immune cells during heart regeneration. Developmental Dynamics 245:774-787, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Perkembangan Terkini Membran Guided Tissue Regeneration/Guided Bone Regeneration sebagai Terapi Regenerasi Jaringan Periodontal

    Directory of Open Access Journals (Sweden)

    Cindy Cahaya

    2015-06-01

    kombinasi prosedur-prosedur di atas, termasuk prosedur bedah restoratif yang berhubungan dengan rehabilitasi oral dengan penempatan dental implan. Pada tingkat selular, regenerasi periodontal adalah proses kompleks yang membutuhkan proliferasi yang terorganisasi, differensiasi dan pengembangan berbagai tipe sel untuk membentuk perlekatan periodontal. Rasionalisasi penggunaan guided tissue regeneration sebagai membran pembatas adalah menahan epitel dan gingiva jaringan pendukung, sebagai barrier membrane mempertahankan ruang dan gigi serta menstabilkan bekuan darah. Pada makalah ini akan dibahas sekilas mengenai 1. Proses penyembuhan terapi periodontal meliputi regenerasi, repair ataupun pembentukan perlekatan baru. 2. Periodontal spesific tissue engineering. 3. Berbagai jenis membran/guided tissue regeneration yang beredar di pasaran dengan keuntungan dan kerugian sekaligus karakteristik masing-masing membran. 4. Perkembangan membran terbaru sebagai terapi regenerasi penyakit periodontal. Tujuan penulisan untuk memberi gambaran masa depan mengenai terapi regenerasi yang menjanjikan sebagai perkembangan terapi penyakit periodontal.   Latest Development of Guided Tissue Regeneration and Guided Bone Regeneration Membrane as Regenerative Therapy on Periodontal Tissue. Periodontitis is a patological state which influences the integrity of periodontal system that could lead to the destruction of the periodontal tissue and end up with tooth loss. Currently, there are so many researches and efforts to regenerate periodontal tissue, not only to stop the process of the disease but also to reconstruct the periodontal tissue. Periodontal regenerative therapy aims at directing the growth of new bone, cementum and periodontal ligament on the affected teeth. Regenerative procedures consist of soft tissue graft, bone graft, roots biomodification, guided tissue regeneration and combination of the procedures, including restorative surgical procedure that is

  13. Optical Regeneration and Noise in Semiconductor Devices

    DEFF Research Database (Denmark)

    Öhman, Filip

    2005-01-01

    In this report all-optical 2R-regeneration in optical communication systems is investigated. A simple regenerator device based on concatenated semiconductor optical amplifiers (SOAs) and electro absorbers (EAs) is introduced and examined. Experiments show that the monolithic SOA-EA 2R-regenerator......In this report all-optical 2R-regeneration in optical communication systems is investigated. A simple regenerator device based on concatenated semiconductor optical amplifiers (SOAs) and electro absorbers (EAs) is introduced and examined. Experiments show that the monolithic SOA-EA 2R...

  14. Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration.

    Science.gov (United States)

    Albanese, Antonino; Licata, Maria E; Polizzi, Bianca; Campisi, Giuseppina

    2013-06-13

    Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients. PRP derives from the centrifugation of the patient's own blood and it contains growth factors that influence wound healing, thereby playing an important role in tissue repairing mechanisms. The use of PRP in surgical practice could have beneficial outcomes, reducing bleeding and enhancing soft tissue healing and bone regeneration. Studies conducted on humans have yielded promising results regarding the application of PRP to many dental and oral surgical procedures (i.e. tooth extractions, periodontal surgery, implant surgery). The use of PRP has also been proposed in the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) with the aim of enhancing wound healing and bone maturation. The aims of this narrative review are: i) to describe the different uses of PRP in dental surgery (tooth extractions and periodontal surgery) and oral surgery (soft tissues and bone tissue surgery, implant surgery and BRONJ surgery); and ii) to discuss its efficacy, efficiency and risk/benefit ratio. This review suggests that the use of PRP in the alveolar socket after tooth extractions is certainly capable of improving soft tissue healing and positively influencing bone regeneration but the latter effect seems to decrease a few days after the extraction. PRP has produced better results in periodontal therapy in association with other materials than when it is used alone. Promising results have also been obtained in implant surgery, when PRP was used in isolation as a coating material. The combination of necrotic bone curettage and PRP application seem to be encouraging for the treatment of refractory BRONJ, as it has proven successful outcomes with minimal invasivity. Since PRP is free from potential risks for patients, not difficult to obtain and use, it can be employed

  15. Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration

    Science.gov (United States)

    2013-01-01

    Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients. PRP derives from the centrifugation of the patient's own blood and it contains growth factors that influence wound healing, thereby playing an important role in tissue repairing mechanisms. The use of PRP in surgical practice could have beneficial outcomes, reducing bleeding and enhancing soft tissue healing and bone regeneration. Studies conducted on humans have yielded promising results regarding the application of PRP to many dental and oral surgical procedures (i.e. tooth extractions, periodontal surgery, implant surgery). The use of PRP has also been proposed in the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) with the aim of enhancing wound healing and bone maturation. The aims of this narrative review are: i) to describe the different uses of PRP in dental surgery (tooth extractions and periodontal surgery) and oral surgery (soft tissues and bone tissue surgery, implant surgery and BRONJ surgery); and ii) to discuss its efficacy, efficiency and risk/benefit ratio. This review suggests that the use of PRP in the alveolar socket after tooth extractions is certainly capable of improving soft tissue healing and positively influencing bone regeneration but the latter effect seems to decrease a few days after the extraction. PRP has produced better results in periodontal therapy in association with other materials than when it is used alone. Promising results have also been obtained in implant surgery, when PRP was used in isolation as a coating material. The combination of necrotic bone curettage and PRP application seem to be encouraging for the treatment of refractory BRONJ, as it has proven successful outcomes with minimal invasivity. Since PRP is free from potential risks for patients, not difficult to obtain and use, it can be employed

  16. Expression and localization of regenerating gene I in a rat liver regeneration model

    International Nuclear Information System (INIS)

    Wang Jingshu; Koyota, Souichi; Zhou, Xiaoping; Ueno, Yasuharu; Ma Li; Kawagoe, Masami; Koizumi, Yukio; Okamoto, Hiroshi; Sugiyama, Toshihiro

    2009-01-01

    Regenerating gene (Reg) I has been identified as a regenerative/proliferative factor for pancreatic islet cells. We examined Reg I expression in the regenerating liver of a rat model that had been administered 2-acetylaminofluorene and treated with 70% partial hepatectomy (2-AAF/PH model), where hepatocyte and cholangiocyte proliferation was suppressed and the hepatic stem cells and/or hepatic progenitor cells were activated. In a detailed time course study of activation of hepatic stem cells in the 2-AAF/PH model, utilizing immunofluorescence staining with antibodies of Reg I and other cell-type-specific markers, we found that Reg I-expressing cells are present in the bile ductules and increased during regeneration. Reg I-expressing cells were colocalized with CK19, OV6, and AFP. These results demonstrate that Reg I is significantly upregulated in the liver of the 2-AAF/PH rat model, accompanied by the formation of bile ductules during liver regeneration.

  17. Nerves Regulate Cardiomyocyte Proliferation and Heart Regeneration.

    Science.gov (United States)

    Mahmoud, Ahmed I; O'Meara, Caitlin C; Gemberling, Matthew; Zhao, Long; Bryant, Donald M; Zheng, Ruimao; Gannon, Joseph B; Cai, Lei; Choi, Wen-Yee; Egnaczyk, Gregory F; Burns, Caroline E; Burns, C Geoffrey; MacRae, Calum A; Poss, Kenneth D; Lee, Richard T

    2015-08-24

    Some organisms, such as adult zebrafish and newborn mice, have the capacity to regenerate heart tissue following injury. Unraveling the mechanisms of heart regeneration is fundamental to understanding why regeneration fails in adult humans. Numerous studies have revealed that nerves are crucial for organ regeneration, thus we aimed to determine whether nerves guide heart regeneration. Here, we show using transgenic zebrafish that inhibition of cardiac innervation leads to reduction of myocyte proliferation following injury. Specifically, pharmacological inhibition of cholinergic nerve function reduces cardiomyocyte proliferation in the injured hearts of both zebrafish and neonatal mice. Direct mechanical denervation impairs heart regeneration in neonatal mice, which was rescued by the administration of neuregulin 1 (NRG1) and nerve growth factor (NGF) recombinant proteins. Transcriptional analysis of mechanically denervated hearts revealed a blunted inflammatory and immune response following injury. These findings demonstrate that nerve function is required for both zebrafish and mouse heart regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Animal regeneration: ancestral character or evolutionary novelty?

    Science.gov (United States)

    Slack, Jonathan Mw

    2017-09-01

    An old question about regeneration is whether it is an ancestral character which is a general property of living matter, or whether it represents a set of specific adaptations to the different circumstances faced by different types of animal. In this review, some recent results on regeneration are assessed to see if they can throw any new light on this question. Evidence in favour of an ancestral character comes from the role of Wnt and bone morphogenetic protein signalling in controlling the pattern of whole-body regeneration in acoels, which are a basal group of bilaterian animals. On the other hand, there is some evidence for adaptive acquisition or maintenance of the regeneration of appendages based on the occurrence of severe non-lethal predation, the existence of some novel genes in regenerating organisms, and differences at the molecular level between apparently similar forms of regeneration. It is tentatively concluded that whole-body regeneration is an ancestral character although has been lost from most animal lineages. Appendage regeneration is more likely to represent a derived character resulting from many specific adaptations. © 2017 The Author.

  19. All optical regeneration using semiconductor devices

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Tromborg, Bjarne

    All-optical regeneration is a key functionality for implementing all-optical networks. We present a simple theory for the bit-error-rate in links employing all-optical regenerators, which elucidates the interplay between the noise and and nonlinearity of the regenerator. A novel device structure ...... is analyzed, emphasizing general aspects of active semiconductor waveguides....

  20. Muscle regeneration in mitochondrial myopathies

    DEFF Research Database (Denmark)

    Krag, T O; Hauerslev, S; Jeppesen, T D

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  1. Lunar Oxygen Production and Metals Extraction Using Ionic Liquids

    Science.gov (United States)

    Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

    2009-01-01

    Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

  2. Optimization of chemical regeneration procedures of spent activated carbon

    Directory of Open Access Journals (Sweden)

    Naser Ghasemzadeh

    2017-01-01

    Full Text Available The chemical regeneration of granular activated carbon exhausted in a petrochemical wastewater unit was investigated. Gas chromatography and energy-dispersive X-ray spectroscopy demonstrated that spent activated carbon carries large types of organic and inorganic materials. Diverse chemical solvents were adopted in comparison with traditional chemical solvents and regeneration efficiency was investigated for each approach. The optimum procedure and optimum condition including temperature, concentration of solvent, and time were determined. The regenerated activated carbon was used in the adsorption of methylene blue (MB in order to find its regeneration efficiency. The regeneration efficiency can be identified by comparing of amount of MB absorbed by the fresh and regenerated activated carbon. The best acidic regenerator was hydrofluoric acid. The higher the temperature causes the faster desorption rate and consequently, the higher regeneration efficiency. The regeneration efficiency increased by means of an increase in the time of regeneration and solvent concentration, but there was an optimum time and solvent concentration for regeneration. The optimum temperature, solvent concentration and regeneration time obtained was 80 ⁰C, 3 molar and 3 hours, respectively.

  3. Infection and Pulp Regeneration

    Directory of Open Access Journals (Sweden)

    Sahng G. Kim

    2016-03-01

    Full Text Available The regeneration of the pulp-dentin complex has been a great challenge to both scientists and clinicians. Previous work has shown that the presence of prior infection may influence the characteristics of tissues formed in the root canal space after regenerative endodontic treatment. The formation of ectopic tissues such as periodontal ligament, bone, and cementum has been observed in the root canal space of immature necrotic teeth with apical periodontitis, while the regeneration of dentin and pulp has been identified in previously non-infected teeth. The current regenerative endodontic therapy utilizes disinfection protocols, which heavily rely on chemical irrigation using conventional disinfectants. From a microbiological point of view, the current protocols may not allow a sufficiently clean root canal microenvironment, which is critical for dentin and pulp regeneration. In this article, the significance of root canal disinfection in regenerating the pulp-dentin complex, the limitations of the current regenerative endodontic disinfection protocols, and advanced disinfection techniques designed to reduce the microorganisms and biofilms in chronic infection are discussed.

  4. Modeling water and hydrogen networks with partitioning regeneration units

    Directory of Open Access Journals (Sweden)

    W.M. Shehata

    2015-03-01

    Full Text Available Strict environment regulations in chemical and refinery industries lead to minimize resource consumption by designing utility networks within industrial process plants. The present study proposed a superstructure based optimization model for the synthesis of water and hydrogen networks with partitioning regenerators without mixing the regenerated sources. This method determines the number of partitioning regenerators needed for the regeneration of the sources. The number of the regenerators is based on the number of sources required to be treated for recovery. Each source is regenerated in an individual partitioning regenerator. Multiple regeneration systems can be employed to achieve minimum flowrate and costs. The formulation is linear in the regenerator balance equations. The optimized model is applied for two systems, partitioning regeneration systems of the fixed outlet impurity concentration and partitioning regeneration systems of the fixed impurity load removal ratio (RR for water and hydrogen networks. Several case studies from the literature are solved to illustrate the ease and applicability of the proposed method.

  5. Intensification of conversion of glucose to lactic acid : equilibria and kinetics for back extraction of lactic acid using trimethylamine

    NARCIS (Netherlands)

    Wasewar, Kailas L.; Heesink, A. Bert M.; Versteeg, Geert F.; Pangarkar, Vishwas G.

    2004-01-01

    Alamine 336 is an effective extractant for the recovery of lactic acid from aqueous solutions. An approach for regeneration and product recovery from such extracts is to back extract lactic acid with a water soluble, volatile tertiary amine such as trimethyl amine. Equilibrium data are presented

  6. Intensification of conversion of glucose to lactic acid: equilibria and kinetics for back extraction of lactic acid using trimethylamine

    NARCIS (Netherlands)

    Wasewar, Kailas L.; Heesink, Albertus B.M.; Versteeg, Geert; Pangarkar, Vishwas G.

    2004-01-01

    Alamine 336 is an effective extractant for the recovery of lactic acid from aqueous solutions. An approach for regeneration and product recovery from such extracts is to back extract lactic acid with a water soluble, volatile tertiary amine such as trimethyl amine. Equilibrium data are presented

  7. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  8. Neurotransmitter-Regulated Regeneration in the Zebrafish Retina

    Directory of Open Access Journals (Sweden)

    Mahesh B. Rao

    2017-04-01

    Full Text Available Summary: Current efforts to repair damaged or diseased mammalian retinas are inefficient and largely incapable of fully restoring vision. Conversely, the zebrafish retina is capable of spontaneous regeneration upon damage using Müller glia (MG-derived progenitors. Understanding how zebrafish MG initiate regeneration may help develop new treatments that prompt mammalian retinas to regenerate. We show that inhibition of γ-aminobutyric acid (GABA signaling facilitates initiation of MG proliferation. GABA levels decrease following damage, and MG are positioned to detect decreased ambient levels and undergo dedifferentiation. Using pharmacological and genetic approaches, we demonstrate that GABAA receptor inhibition stimulates regeneration in undamaged retinas while activation inhibits regeneration in damaged retinas. : Unlike mammals, zebrafish regenerate following retina damage from a resident adult stem cell (Müller glia. Dissecting the mechanisms that zebrafish use could lead to new therapeutic targets to treat retinal diseases. Patton and colleagues have discovered a mechanism by which decreased GABA levels are sensed by Müller glia to initiate a regenerative response. Keywords: zebrafish, retina, regeneration, Müller glia, GABA

  9. [Guided bone regeneration: general survey].

    Science.gov (United States)

    Cosyn, Jan; De Bruyn, Hugo

    2009-01-01

    The principle of 'guided bone regeneration' was first described in 1988 on the basis of animal-experimental data. Six weeks after transmandibular defects had been created and protected by non-resorbable teflonmembranes, complete bone regeneration was found. The technique was based on the selective repopulation of the wound: every infiltration of cells outside the neighbouring bone tissue was prevented by the application of the membrane. Additional animal experiments showed that guided bone regeneration was a viable treatment option for local bone defects surrounding dental implants. Clinical practice, however, showed that premature membrane exposure was a common complication, which was responsible for a tremendous reduction in regenerated bone volume. In addition, a second surgical intervention was always necessary to remove the membrane. As a result, resorbable alternatives were developed. Since these are less rigid, bone fillers are usually used simultaneously. These comprise autogenous bone chips and bone substitutes from allogenic or xenogenic origine. Also alloplastic materials could be used for this purpose. Based on their characteristics this article provides an overview of the biomaterials that could be considered for guided bone regeneration. Specific attention goes to their application in clinical practice.

  10. Peptide-Based Materials for Cartilage Tissue Regeneration.

    Science.gov (United States)

    Hastar, Nurcan; Arslan, Elif; Guler, Mustafa O; Tekinay, Ayse B

    2017-01-01

    Cartilaginous tissue requires structural and metabolic support after traumatic or chronic injuries because of its limited capacity for regeneration. However, current techniques for cartilage regeneration are either invasive or ineffective for long-term repair. Developing alternative approaches to regenerate cartilage tissue is needed. Therefore, versatile scaffolds formed by biomaterials are promising tools for cartilage regeneration. Bioactive scaffolds further enhance the utility in a broad range of applications including the treatment of major cartilage defects. This chapter provides an overview of cartilage tissue, tissue defects, and the methods used for regeneration, with emphasis on peptide scaffold materials that can be used to supplement or replace current medical treatment options.

  11. Brownfield regeneration: Towards strengthening social cohesion?

    Directory of Open Access Journals (Sweden)

    Minić Marta

    2016-01-01

    Full Text Available In broader terms, the paper refers to the topic of brownfield regeneration, as one of the most complex mechanisms for sustainable spatial development. In addition to the fact that brownfield regeneration demands a variety of instruments, such as: tax subsidies, the change of land use ownership, soil remediation, planning regulative amendments, etc., the complexity of brownfield regeneration is primarily seen in a number of stakeholders participating in such a process. Thus, the paper focuses on the social aspect of brownfield regeneration - precisely, on researching the community role and reviewing the possibilities for achieving the 'local' interests in complex developmental processes. The main research hypothesis is that brownfield regeneration positively affects the creation of and strengthening the social cohesion in the areas close to the brownfield site. More precisley, the paper presents the ways towards strenghtening social cohesion in the initial phase of the brownfield regeneration process, as well as the effects of such a process in its operationalisation phase on social cohesion. The thesis is examined by two main parameters: 1 participation of local community, and 2 social costs and benefits of brownfield regeneration versus greenfield investment. The research results are presented in the form of argumentative essay. In fact, the critical overview of arguments for and against the main research hypothesis is provided based on the review of interdisciplinary literature in the domain of brownfield regeneration. Such research organisation ensures the identification and description of the measures needed for strengthening social cohesion, as an utmost goal of this research. The final research contribution is about offering the guidelines for similar methodological approach in urban research.

  12. Hydroprocessing catalysts utilization and regeneration schemes

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    The catalyst reactor inventory represents an important part of the cost of hydroprocessing operation. The selection of a suitable catalyst and reactor is influenced by feedstock properties. Processes ensuring an uninterrupted operation during catalyst addition and withdrawal are preferred for processing high asphaltene and metal content feedstocks. The spent catalyst can be regenerated and returned to the operation if the extent of its deactivation is not high. The regeneration may be performed either in-situ or off-site. The former is suitable for fixed bed reactors whereas the catalyst from ebullated bed reactors must be regenerated off-site. The regeneration of spent catalysts heavily loaded with metals such as V, Ni and Fe may not be economic. Such catalysts may be suitable for metal reclamation. An environmentally safe method for catalyst disposal must be found if neither regeneration nor metal reclamation from spent catalysts can be performed.

  13. Regeneration limit of classical Shannon capacity

    Science.gov (United States)

    Sorokina, M. A.; Turitsyn, S. K.

    2014-05-01

    Since Shannon derived the seminal formula for the capacity of the additive linear white Gaussian noise channel, it has commonly been interpreted as the ultimate limit of error-free information transmission rate. However, the capacity above the corresponding linear channel limit can be achieved when noise is suppressed using nonlinear elements; that is, the regenerative function not available in linear systems. Regeneration is a fundamental concept that extends from biology to optical communications. All-optical regeneration of coherent signal has attracted particular attention. Surprisingly, the quantitative impact of regeneration on the Shannon capacity has remained unstudied. Here we propose a new method of designing regenerative transmission systems with capacity that is higher than the corresponding linear channel, and illustrate it by proposing application of the Fourier transform for efficient regeneration of multilevel multidimensional signals. The regenerative Shannon limit—the upper bound of regeneration efficiency—is derived.

  14. Optimal Management of Geothermal Heat Extraction

    Science.gov (United States)

    Patel, I. H.; Bielicki, J. M.; Buscheck, T. A.

    2015-12-01

    Geothermal energy technologies use the constant heat flux from the subsurface in order to produce heat or electricity for societal use. As such, a geothermal energy system is not inherently variable, like systems based on wind and solar resources, and an operator can conceivably control the rate at which heat is extracted and used directly, or converted into a commodity that is used. Although geothermal heat is a renewable resource, this heat can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal (Rybach, 2003). For heat extraction used for commodities that are sold on the market, sustainability entails balancing the rate at which the reservoir renews with the rate at which heat is extracted and converted into profit, on a net present value basis. We present a model that couples natural resource economic approaches for managing renewable resources with simulations of geothermal reservoir performance in order to develop an optimal heat mining strategy that balances economic gain with the performance and renewability of the reservoir. Similar optimal control approaches have been extensively studied for renewable natural resource management of fisheries and forests (Bonfil, 2005; Gordon, 1954; Weitzman, 2003). Those models determine an optimal path of extraction of fish or timber, by balancing the regeneration of stocks of fish or timber that are not harvested with the profit from the sale of the fish or timber that is harvested. Our model balances the regeneration of reservoir temperature with the net proceeds from extracting heat and converting it to electricity that is sold to consumers. We used the Non-isothermal Unconfined-confined Flow and Transport (NUFT) model (Hao, Sun, & Nitao, 2011) to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are incorporated into the natural resource economics model to determine production strategies that

  15. Comparison contemporary methods of regeneration sodium-cationic filters

    Science.gov (United States)

    Burakov, I. A.; Burakov, A. Y.; Nikitina, I. S.; Verkhovsky, A. E.; Ilyushin, A. S.; Aladushkin, S. V.

    2017-11-01

    Regeneration plays a crucial role in the field of efficient application sodium-cationic filters for softening the water. Traditionally used as regenerant saline NaCl. However, due to the modern development of the energy industry and its close relationship with other industrial and academic sectors the opportunity to use in the regeneration of other solutions. The report estimated data and application possibilities as regenerant solution sodium-cationic filters brine wells a high mineral content, as both primary application and after balneotherapeutic use reverse osmosis and concentrates especially recycled regenerant water repeated. Comparison of the effectiveness of these solutions with the traditional use of NaCl. Developed and tested system for the processing of highly mineralized brines wells after balneological use. Recommendations for use as regeneration solutions for the sodium-cationic unit considered solutions and defined rules of brine for regeneration costs.

  16. Regeneration of limb joints in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Lee, Jangwoo; Gardiner, David M

    2012-01-01

    In spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. An understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. To this end, we have used the axolotl (Mexican Salamander) model of limb regeneration to describe the morphology and the expression patterns of marker genes during joint regeneration in response to limb amputation. These data are consistent with the hypothesis that the mechanisms of joint formation whether it be development or regeneration are conserved. We also have determined that defects in the epiphyseal region of both forelimbs and hind limbs in the axolotl are regenerated only when the defect is small. As is the case with defects in the diaphysis, there is a critical size above which the endogenous regenerative response is not sufficient to regenerate the joint. This non-regenerative response in an animal that has the ability to regenerate perfectly provides the opportunity to screen for the signaling pathways to induce regeneration of articular cartilage and joints.

  17. Regeneration of limb joints in the axolotl (Ambystoma mexicanum.

    Directory of Open Access Journals (Sweden)

    Jangwoo Lee

    Full Text Available In spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. An understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. To this end, we have used the axolotl (Mexican Salamander model of limb regeneration to describe the morphology and the expression patterns of marker genes during joint regeneration in response to limb amputation. These data are consistent with the hypothesis that the mechanisms of joint formation whether it be development or regeneration are conserved. We also have determined that defects in the epiphyseal region of both forelimbs and hind limbs in the axolotl are regenerated only when the defect is small. As is the case with defects in the diaphysis, there is a critical size above which the endogenous regenerative response is not sufficient to regenerate the joint. This non-regenerative response in an animal that has the ability to regenerate perfectly provides the opportunity to screen for the signaling pathways to induce regeneration of articular cartilage and joints.

  18. Composite Matrix Regenerator for Stirling Engines

    Science.gov (United States)

    Knowles, Timothy R.

    1997-01-01

    This project concerns the design, fabrication and testing of carbon regenerators for use in Stirling power convertors. Radial fiber design with nonmetallic components offers a number of potential advantages over conventional steel regenerators: reduced conduction and pressure drop losses, and the capability for higher temperature, higher frequency operation. Diverse composite fabrication methods are explored and lessons learned are summarized. A pulsed single-blow test rig has been developed that has been used for generating thermal effectiveness data for different flow velocities. Carbon regenerators have been fabricated by carbon vapor infiltration of electroflocked preforms. Performance data in a small Stirling engine are obtained. Prototype regenerators designed for the BP-1000 power convertor were fabricated and delivered to NASA-Lewis.

  19. Limb Regeneration in Axolotl: Is It Superhealing?

    Directory of Open Access Journals (Sweden)

    Stéphane Roy

    2006-01-01

    Full Text Available The ability of axolotls to regenerate their limbs is almost legendary. In fact, urodeles such as the axolotl are the only vertebrates that can regenerate multiple structures like their limbs, jaws, tail, spinal cord, and skin (the list goes on throughout their lives. It is therefore surprising to realize, although we have known of their regenerative potential for over 200 years, how little we understand the mechanisms behind this achievement of adult tissue morphogenesis. Many observations can be drawn between regeneration and other disciplines such as development and wound healing. In this review, we present new developments in functional analysis that will help to address the role of specific genes during the process of regeneration. We also present an analysis of the resemblance between wound healing and regeneration, and discuss whether axolotls are superhealers. A better understanding of these animals' regenerative capacity could lead to major benefits by providing regenerative medicine with directions on how to develop therapeutic approaches leading to regeneration in humans.

  20. Irradiation inhibits the regeneration of aneurogenic limbs

    International Nuclear Information System (INIS)

    Wallace, H.; Maden, M.

    1976-01-01

    The developing arms of axolotl larvae from the 2-digit stage onward and the aneurogenic arms of surgically denervated larvae maintained in parabiosis are able to regenerate after amputation. Such regeneration is uniformly inhibited by local irradiation of the arm, whether innervated or not. This demonstration refutes a recent hypothesis that x-rays interfere with a special activity of nerves required for regeneration, and supports the earlier concept that x-rays act directly on those cells which must proliferate to form the regenerated tissues

  1. Separation of uranium from aqueous solutions using calix[6]arenes in liquid-liquid extraction as well as solid phase extraction

    International Nuclear Information System (INIS)

    Schmeide, K.; Geipel, G.; Bernhard, G.

    2004-11-01

    The suitability of different calyx[n] arene types for uranyl extraction from liquid solutions was examined by means of liquid-liquid extraction using aqueous phases and organic solvents of varying compositions. It was found that COOH-derivatised calyx[6] arenes have good extraction properties and can even be used in the acid pH range. The use of calixarene-modified fleeces for the separation of uranyl from aqueous phases was examined in batch experiments with pH and uranyl concentration as variables and in the presence or absence of competing ions. The results showed that calixarene-modified fleeces can be used for uranium separation starting from pH 4. At pH 5, up to a maximum of 7.6 x 10 -7 mol uranium can be bound per 1 g of calixarene-modified fleece. The separation of uranyl from synthetic pit waters was examined as a means of testing the separation capacity of calixarene-modified fleeces in environmentally sensitive waters. Studies on the reversibility of uranium bonding to calixarene-treated polyester fleeces have shown that under environmentally realistic conditions (neutral pH range) the uranium is firmly bound to the calixarene-modified fleeces and cannot be mobilised. By contrast, in acidic environments calixarene-modified fleeces are capable of near-complete regeneration. Such regenerated textile filter materials can then be used for further uranium separation cycles [de

  2. Cardiac regeneration therapy: connections to cardiac physiology.

    Science.gov (United States)

    Takehara, Naofumi; Matsubara, Hiroaki

    2011-12-01

    Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility.

  3. Internodal function in normal and regenerated mammalian axons

    DEFF Research Database (Denmark)

    Moldovan, M; Krarup, C

    2007-01-01

    AIM: Following Wallerian degeneration, peripheral myelinated axons have the ability to regenerate and, given a proper pathway, establish functional connections with targets. In spite of this capacity, the clinical outcome of nerve regeneration remains unsatisfactory. Early studies have found...... that regenerated internodes remain persistently short though this abnormality did not seem to influence recovery in conduction. It remains unclear to which extent abnormalities in axonal function itself may contribute to the poor outcome of nerve regeneration. METHODS: We review experimental evidence indicating...... that internodes play an active role in axonal function. RESULTS: By investigating internodal contribution to axonal excitability we have found evidence that axonal function may be permanently compromised in regenerated nerves. Furthermore, we illustrate that internodal function is also abnormal in regenerated...

  4. Autoradiographic analysis of protein regeneration in striated skeleton muscle

    International Nuclear Information System (INIS)

    Dadoune, J.P.

    1977-01-01

    An autoradiographic study was conducted of protein regeneration in striated muscles aimed at clarifying the contradictions in the literature: while some authors hold that the regeneration rate is identical for all types of myofibril proteins and the myofibril is thus regenerated as a whole, others claim that the regeneration rate differs depending on the type of the myofibril protein. Tritium-labelled leucine incorporation experiments showed the existence of at least 2 pools of newly formed proteins in striated muscles in both adult and young animals. One pool is regenerated in 1 to 2 weeks, the other roughly in a month. The regeneration of proteins is initially more significant in red fibres; thus the rate of myofibril protein regeneration is not uniform. In adult animals regeneration seems to be slower in filaments than in the sarcoplasm and in the mitochondria. (A.K.)

  5. Apparatus and methods for regeneration of precipitating solvent

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, Wan Wang; Bonsu, Alexander

    2015-08-25

    A regenerator that can handle rich loaded chemical solvent containing precipitated absorption reaction products is disclosed. The invention is particularly suitable for separating CO.sub.2 from large gas streams that are typical of power plant processes. The internally circulating liquid stream in the regenerator (ICLS regenerator) rapidly heats-up the in-coming rich solvent stream in a downcomer standpipe as well as decreases the overall concentration of CO.sub.2 in the mixed stream. Both these actions lead to dissolution of precipitates. Any remaining precipitate further dissolves as heat is transferred to the mixed solution with an inverted bayonet tube heat exchanger in the riser portion of the regenerator. The evolving CO.sub.2 bubbles in the riser portion of the regenerator lead to substantial gas hold-up and the large density difference between the solutions in the downcomer standpipe and riser portions promotes internal circulation of the liquid stream in the regenerator. As minor amounts of solvent components present in the exit gas stream are condensed and returned back to the regenerator, pure CO.sub.2 gas stream exits the disclosed regenerator and condenser system.

  6. FEATURES OF THE REGENERATION PROCESS OF THE FILTER

    Directory of Open Access Journals (Sweden)

    S. Yu. Panov

    2015-01-01

    Full Text Available The regeneration system exercises significant influence on the efficiency and reliability of the filters. During operation of the filter it continuously increases the hydraulic resistance and the gas permeability of the filter material decreases as the deposition of the disperse phase capturable on the filter element, and to maintain the bandwidth of the filter in the filter element within the set must be periodically changed or regenerated. Thus, regeneration of a process of removing part of the dust layer with the purpose of full or partial reduction of the initial filter partitioning properties. On the basis of theoretical synthesis, physico-chemical effects of dust in layers, analysis of energy effects, developed methods of intensification of the process of regeneration of particulate filters. Pneumopulse regeneration of bag filter has been investigated, and based on it a regression equation for regeneration efficiency has been derived. It has been shown that pulse pressure exerts the dominant influence on the regeneration efficiency. The obtained model was used for assessment and prediction of the efficiency of the pneumopulse system of regeneration of bag filters at a number of structural materials producing enterprises in the Voronezh region.

  7. Periodontal regeneration.

    Science.gov (United States)

    Ivanovski, S

    2009-09-01

    The ultimate goal of periodontal therapy is the regeneration of the tissues destroyed as a result of periodontal disease. Currently, two clinical techniques, based on the principles of "guided tissue regeneration" (GTR) or utilization of the biologically active agent "enamel matrix derivative" (EMD), can be used for the regeneration of intrabony and Class II mandibular furcation periodontal defects. In cases where additional support and space-making requirements are necessary, both of these procedures can be combined with a bone replacement graft. There is no evidence that the combined use of GTR and EMD results in superior clinical results compared to the use of each material in isolation. Great variability in clinical outcomes has been reported in relation to the use of both EMD and GTR, and these procedures can be generally considered to be unpredictable. Careful case selection and treatment planning, including consideration of patient, tooth, site and surgical factors, is required in order to optimize the outcomes of treatment. There are limited data available for the clinical effectiveness of other biologically active molecules, such as growth factors and platelet concentrates, and although promising results have been reported, further clinical trials are required in order to confirm their effectiveness. Current active areas of research are centred on tissue engineering and gene therapy strategies which may result in more predictable regenerative outcomes in the future.

  8. Biological regeneration of phenol-loaded activated carbon (up flow system)

    International Nuclear Information System (INIS)

    Durrani, M.A.Q.J.; Mirajuddin; Martin, R.J.

    1995-01-01

    This paper represents the report on the biological regeneration of totally activated carbon following the experimental studies carried out at the University of Birmingham, U.K. Biological regeneration is one of several methods that may be used to restore the adsorptive capacity of exhausted granular activated carbon. This study deals with in situ biological regeneration on a pilot scale. The principal objective of this research was to ascertain whether biological regeneration of GAC could occur under conditions typical of water treatment. The important parameters which may have the greatest impact on bio regeneration for a given adsorbate were studied. The research investigated the extent of bio regeneration for phenol of concentration 50 mg/l. Bio regeneration in the total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bio regeneration run. The prepared carbon was initialing exhausted with an adsorbate; it was then bio regenerated with a mixed culture of bacteria, and lastly the carbon was saturated. In the totally exhausted GAC system, the bio regeneration was enhanced by increasing the duration of regeneration for a fixed initial biomass content of the bioreactor. The regenerated phenol loaded GAC bed had nearly gained its original adsorption after the 5-day period of regeneration. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents. (author)

  9. Pulp regeneration: Current approaches and future challenges

    Directory of Open Access Journals (Sweden)

    Jingwen eYANG

    2016-03-01

    Full Text Available Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α, basic Fibroblast Growth Factor (bFGF, Platelet Derived Growth Factor (PDGF, stem cell factor (SCF, and Granulocyte Colony-Stimulating Factor (G-CSF were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration.

  10. Applications of Metals for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Kristina Glenske

    2018-03-01

    Full Text Available The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP-based substitute materials based on natural (allo- and xenografts and synthetic origins (alloplastic materials are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

  11. The influence of regeneration fellings on the development of artificially regenerated beech (Fagus sylvatica L.) plantations

    Czech Academy of Sciences Publication Activity Database

    Bednář, Pavel; Černý, J.

    2014-01-01

    Roč. 62, č. 5 (2014), s. 859-867 ISSN 1211-8516 Institutional support: RVO:67179843 Keywords : European beech * regeneration felling * artificial regeneration * height * DBH – the diameter at breast-height * quality * ISF – Indirect Site Factor Subject RIV: GK - Forestry

  12. Manipulations to regenerate aspen ecosystems

    Science.gov (United States)

    Wayne D. Shepperd

    2001-01-01

    Vegetative regeneration of aspen can be initiated through manipulations that provide hormonal stimulation, proper growth environment, and sucker protection - the three elements of the aspen regeneration triangle. The correct course of action depends upon a careful evaluation of the size, vigor, age, and successional status of the existing clone. Soils and site...

  13. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Katykhin, G.S.

    1978-01-01

    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  14. Setd7 and its contribution to boron-induced bone regeneration in B-MBG scaffolds.

    Science.gov (United States)

    Yin, Chengcheng; Jia, Xiaoshi; Miron, Richard J; Long, Qiaoyun; Xu, Hudi; Wei, Yan; Wu, Min; Zhang, Yufeng; Li, Zubing

    2018-04-20

    Boron (B), a trace element found in the human body, plays an important role for health of bone by promoting the proliferation and differentiation of osteoblasts. Our research group previously fabricated B-mesoporous bioactive glass (MBG) scaffolds, which successfully promoted osteogenic differentiation of osteoblasts when compared to pure MBG scaffolds without boron. However, the mechanisms of the positive effect of B-MBG scaffolds on osteogenesis remains unknown. Therefore, we performed in-vivo experiments in an OVX rat models with pure MBG scaffolds and compared them to B-MBG scaffold. As a result, we found that B-MBG scaffold induced more new bone regeneration compared to pure MBG scaffold and examined genes related to bone regeneration induced by B-MBG scaffold through RNA-seq to obtain target genes and epigenetic mechanisms. The results demonstrated an increased expression and affiliation of Setd7 in the B-MBG group when compared to the MBG group. Immunofluorescent staining from our in vivo samples further demonstrated a higher localization of Setd7 and H3K4me3 in Runx2-positive cells in defects treated with B-MBG scaffolds. KEGG results suggested that specifically Wnt/β-catenin signaling pathway was highly activated in new bone area associated with B-MBG scaffolds. Thereafter, in vitro studies with human bone marrow stem cells (hBMSCs) stimulated by extracted liquid of B-MBG was associated with significantly elevated levels of Setd7, as well as H3K4me3 when compared to MBG alone. To verify the role of Setd7 in new bone formation in the presence of Boron, Setd7 was knocked down in hBMSCs with stimulation of the extracted liquids of B-MBG or MBG scaffolds. The result showed that osteoblast differentiation of hBMSCs was inhibited when Setd7 was knocked down, which could not be rescued by the extract liquids of B-MBG scaffolds confirming its role in osteoblast differentiation and bone regeneration. As a histone methylase, Setd7 may be expected to be a potential

  15. Regenerating America: Meeting the Challenge of Building Local Economies.

    Science.gov (United States)

    Gabel, Medard; And Others

    The document includes five papers on the implications and applications of regeneration by the Regeneration Project, based in Emmaus, Pa. The first paper, "Regenerating America: Meeting the Challenge of Building Local Economies," (Medard Gabel) defines regeneration as economic recovery and growth, fostered by diversification within a…

  16. Enhancement of organ regeneration in animal models by a stem cell-stimulating plant mixture.

    Science.gov (United States)

    Kiss, István; Tibold, Antal; Halmosi, Róbert; Bartha, Eva; Koltai, Katalin; Orsós, Zsuzsanna; Bujdosó, László; Ember, István

    2010-06-01

    Adult stem cells play an important role in the regeneration of damaged organs. Attempts have already been made to enhance stem cell production by cytokines, in order to increase the improvement of cardiac functions after myocardial infarction. In our present study we investigated the possibility whether instead of cytokine injection dietary stimulation of stem cell production accelerates the organ regeneration in animals. A dietary supplement, Olimpiq StemXCell (Crystal Institute Ltd., Eger, Hungary), containing plant extracts (previously proved to increase the number of circulating CD34(+) cells) was consumed in human equivalent doses by the experimental animals. In the first experiment carbon tetrachloride was applied to CBA/Ca mice, to induce liver damage, and liver weights between StemXCell-fed and control animals were compared 10 days after the treatment. In the second model experimental diabetes was induced in F344 rats by alloxan. Blood sugar levels were measured for 5 weeks in the control and StemXCell-fed groups. The third part of the study investigated the effect of StemXCell on cardiac functions. Eight weeks after causing a myocardial infarction in Wistar rats by isoproterenol, left ventricular ejection fraction was determined as a functional parameter of myocardial regeneration. In all three animal models StemXCell consumption statistically significantly improved the organ regeneration (relative liver weights, 4.78 +/-0.06 g/100 g vs. 4.97 +/- 0.07 g/100 g; blood sugar levels at week 5, 16 +/- 1.30 mmol/L vs. 10.2 +/- 0.92 mmol/L; ejection fraction, 57.5 +/- 2.23 vs. 68.2 +/- 4.94; controls vs. treated animals, respectively). Our study confirms the hypothesis that dietary enhancement of stem cell production may protect against organ injuries and helps in the regeneration.

  17. Regeneration of hair cells in the mammalian vestibular system.

    Science.gov (United States)

    Li, Wenyan; You, Dan; Chen, Yan; Chai, Renjie; Li, Huawei

    2016-06-01

    Hair cells regenerate throughout the lifetime of non-mammalian vertebrates, allowing these animals to recover from hearing and balance deficits. Such regeneration does not occur efficiently in humans and other mammals. Thus, balance deficits become permanent and is a common sensory disorder all over the world. Since Forge and Warchol discovered the limited spontaneous regeneration of vestibular hair cells after gentamicininduced damage in mature mammals, significant efforts have been exerted to trace the origin of the limited vestibular regeneration in mammals after hair cell loss. Moreover, recently many strategies have been developed to promote the hair cell regeneration and subsequent functional recovery of the vestibular system, including manipulating the Wnt, Notch and Atoh1. This article provides an overview of the recent advances in hair cell regeneration in mammalian vestibular epithelia. Furthermore, this review highlights the current limitations of hair cell regeneration and provides the possible solutions to regenerate functional hair cells and to partially restore vestibular function.

  18. Experiments and Analysis of DPF Loading and Regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, Krishnan

    2000-08-20

    Particulate filter system consists of a filter and a regeneration strategy Commercial filters are very effective at removing PM, but regeneration is a challenge. In addition to removal of PM if is important to reduce other pollutants including NO, from diesel engine exhaust Particulate filter regeneration strategy can include catalysts, fuel additives, engine control, and fuel injection Regeneration 5M?-500 C without catalyst Near 350 C with fuel additive or catalyst coated DPF

  19. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  20. Zirconia changes after grinding and regeneration firing.

    Science.gov (United States)

    Hatanaka, Gabriel R; Polli, Gabriela S; Fais, Laiza M G; Reis, José Maurício Dos S N; Pinelli, Lígia A P

    2017-07-01

    Despite improvements in computer-aided design and computer-aided manufacturing (CAD-CAM) systems, grinding during either laboratory procedures or clinical adjustments is often needed to modify the shape of 3 mol(%) yttria-tetragonal zirconia polycrystal (3Y-TZP) restorations. However, the best way to achieve adjustment is unclear. The purpose of this in vitro study was to evaluate the microstructural and crystallographic phase changes, flexural strength, and Weibull modulus of a 3Y-TZP zirconia after grinding with or without water cooling and regeneration firing. Ninety-six bar-shaped specimens were obtained and divided as follows: as-sintered, control; as-sintered with regeneration firing; grinding without water cooling; grinding and regeneration firing with water cooling; and grinding and regeneration firing. Grinding (0.3 mm) was performed with a 150-μm diamond rotary instrument in a high-speed handpiece. For regeneration firing, the specimens were annealed at 1000°C for 30 minutes. The crystalline phases were evaluated by using x-ray powder diffraction. A 4-point bending test was conducted (10 kN; 0.5 mm/min). The Weibull modulus was used to analyze strength reliability. The microstructure was analyzed by scanning electron microscopy. Data from the flexural strength test were evaluated using the Kruskal-Wallis and Dunn tests (α=.05). Tetragonal-to-monoclinic phase transformation was identified in the ground specimens; R regeneration firing groups showed only the tetragonal phase. The median flexural strength of as-sintered specimens was 642.0; 699.3 MPa for as-sintered specimens with regeneration firing; 770.1 MPa for grinding and water-cooled specimens; 727.3 MPa for specimens produced using water-cooled grinding and regeneration firing; 859.9 MPa for those produced by grinding; and 764.6 for those produced by grinding and regeneration firing; with statistically higher values for the ground groups. The regenerative firing did not affect the flexural

  1. Finding Urban Identity through Culture-led Urban Regeneration

    Directory of Open Access Journals (Sweden)

    Kyu Hong Hwang

    Full Text Available ABSTRACT: A city experiencing a cycle from growth to decline cannot maintain sustainable development without the type of urban identity that could be consolidated by culture-led urban regeneration. A plan for urban regeneration in a declining urban area should be practiced partially or on the whole according to the characteristics of the community. By transforming a low-value and deteriorated area into a highly valued district, the local community can simultaneously restore its social pride, revive the local economy, and realize an urban identity.Firstly, this paper examines urban decline in order to better understand urban regeneration and the need for multidisciplinary management, and also, by considering the necessity for and universal types of urban regeneration, investigates the characteristics of culture-led urban regeneration as a tool for realizing socio-economic revival and urban identity. In particular, this study suggests the action techniques and benchmarking points for urban regeneration by analyzing cases of culture-led urban regeneration in Korea. Three subjects were considered as case studies in this paper: 1 Hanok village in Jeonju city, which changed from a twilight zone to a tourist attraction; 2 Changdong district in Changwon city, which recovered from an area of declining and dark alleyways that had been the hub for arts and culture in the 1970s to become a new artist village; and 3 Cheongju city, which is being transformed from an idle industrial facility into a cultural space. This thesis suggests the implementation process of culture-led urban regeneration to find an urban identity through analysis of the causes of urban decline, the methods of regeneration, and the results of urban regeneration in the three aforementioned cases. In the conclusion section of this paper, the implementation process for culture-led urban regeneration is summarized as consisting of 5 phases: Phase 1, the diagnosis of decline; Phase 2

  2. Hair cell regeneration in the avian auditory epithelium.

    Science.gov (United States)

    Stone, Jennifer S; Cotanche, Douglas A

    2007-01-01

    Regeneration of sensory hair cells in the mature avian inner ear was first described just over 20 years ago. Since then, it has been shown that many other non-mammalian species either continually produce new hair cells or regenerate them in response to trauma. However, mammals exhibit limited hair cell regeneration, particularly in the auditory epithelium. In birds and other non-mammals, regenerated hair cells arise from adjacent non-sensory (supporting) cells. Hair cell regeneration was initially described as a proliferative response whereby supporting cells re-enter the mitotic cycle, forming daughter cells that differentiate into either hair cells or supporting cells and thereby restore cytoarchitecture and function in the sensory epithelium. However, further analyses of the avian auditory epithelium (and amphibian vestibular epithelium) revealed a second regenerative mechanism, direct transdifferentiation, during which supporting cells change their gene expression and convert into hair cells without dividing. In the chicken auditory epithelium, these two distinct mechanisms show unique spatial and temporal patterns, suggesting they are differentially regulated. Current efforts are aimed at identifying signals that maintain supporting cells in a quiescent state or direct them to undergo direct transdifferentiation or cell division. Here, we review current knowledge about supporting cell properties and discuss candidate signaling molecules for regulating supporting cell behavior, in quiescence and after damage. While significant advances have been made in understanding regeneration in non-mammals over the last 20 years, we have yet to determine why the mammalian auditory epithelium lacks the ability to regenerate hair cells spontaneously and whether it is even capable of significant regeneration under additional circumstances. The continued study of mechanisms controlling regeneration in the avian auditory epithelium may lead to strategies for inducing

  3. Regeneration of neural crest derivatives in the Xenopus tadpole tail

    Directory of Open Access Journals (Sweden)

    Slack Jonathan MW

    2007-05-01

    Full Text Available Abstract Background After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper. Results Labelling of the spinal cord by electroporation, or by orthotopic grafting of transgenic tissue expressing GFP, shows that no cells emigrate from the spinal cord in the course of regeneration. There is very limited regeneration of the spinal ganglia, but new neurons as well as fibre tracts do appear in the regenerated spinal cord and the regenerated tail also contains abundant peripheral innervation. The regenerated tail contains a normal density of melanophores. Cell labelling experiments show that melanophores do not arise from the spinal cord during regeneration, nor from the mesenchymal tissues of the skin, but they do arise by activation and proliferation of pre-existing melanophore precursors. If tails are prepared lacking melanophores, then the regenerates also lack them. Conclusion On regeneration there is no induction of a new neural crest similar to that seen in embryonic development. However there is some regeneration of neural crest derivatives. Abundant melanophores are regenerated from unpigmented precursors, and, although spinal ganglia are not regenerated, sufficient sensory systems are produced to enable essential functions to continue.

  4. REUSABILITY OF BOND ELUT CERTIFY COLUMNS FOR THE EXTRACTION OF DRUGS FROM PLASMA

    NARCIS (Netherlands)

    CHEN, XH; FRANKE, JP; WIJSBEEK, J; DEZEEUW, RA

    1993-01-01

    The reusability of Bond Elut Certify columns for the extraction of toxicologically relevant drugs from plasma has been evaluated. Pentobarbital, hexobarbital, mepivacaine, trimipramine and clonazepam were selected as test drugs to represent various classes of drugs. The columns were regenerated

  5. Thermal and Structural Analysis of Micro-Fabricated Involute Regenerators

    Science.gov (United States)

    Qiu, Songgang; Augenblick, Jack E.

    2005-02-01

    Long-life, high-efficiency power generators based on free-piston Stirling engines are an energy conversion solution for future space power generation and commercial applications. As part of the efforts to further improve Stirling engine efficiency and reliability, a micro-fabricated, involute regenerator structure is proposed by a Cleveland State University-led regenerator research team. This paper reports on thermal and structural analyses of the involute regenerator to demonstrate the feasibility of the proposed regenerator. The results indicate that the involute regenerator has extremely high axial stiffness to sustain reasonable axial compression forces with negligible lateral deformation. The relatively low radial stiffness may impose some challenges to the appropriate installation of the in-volute regenerators.

  6. Method for modifying trigger level for adsorber regeneration

    Science.gov (United States)

    Ruth, Michael J.; Cunningham, Michael J.

    2010-05-25

    A method for modifying a NO.sub.x adsorber regeneration triggering variable. Engine operating conditions are monitored until the regeneration triggering variable is met. The adsorber is regenerated and the adsorbtion efficiency of the adsorber is subsequently determined. The regeneration triggering variable is modified to correspond with the decline in adsorber efficiency. The adsorber efficiency may be determined using an empirically predetermined set of values or by using a pair of oxygen sensors to determine the oxygen response delay across the sensors.

  7. Theoretical study for solar air pretreatment collector/regenerator

    Energy Technology Data Exchange (ETDEWEB)

    Peng Donggen; Zhang Xiaosong; Yin Yonggao [School of Energy and Environment, Southeast Univ., Nanjing (China)

    2008-07-01

    A new liquid regeneration equipment - solar air pretreatment collector/regenerator for liquid desiccant cooling system is put forward in this paper, which is preferable to solution regeneration in hot and moist climate in South China. The equipment can achieve liquid regeneration in lower temperature. When the solution and the air are in ''match'' state in collector/ regenerator, a match air to salt mass ratio ASMR* is found by theoretical study in which there is the largest theoretical storage capacity SC{sub max}. After two new concepts of the effective solution proportion (EPS) and the effective storage capacity (ESC) are defined, it is found by theoretical calculation that when ESP drops from 100% to 67%, ESC raises lowly, not drops and liquid outlet concentration C{sub str} {sub sol} increases from 40% to 49% in which its increment totals to 90%. All these data explain fully that air pretreatment liquid regeneration equipment enables to improve the performance of liquid desiccant cooling system. (orig.)

  8. The potential of mangosteen (Garcinia mangostana peel extract, combined with demineralized freeze-dried bovine bone xenograft, to reduce ridge resorption and alveolar bone regeneration in preserving the tooth extraction socket

    Directory of Open Access Journals (Sweden)

    Utari Kresnoadi

    2017-01-01

    Conclusion: The induction of MPEs and DFBBX is effective in reducing inflammation, lowering osteoclasts, decreasing alveolar bone resorption, and also increasing BMP2 expression and alveolar bone regeneration.

  9. Regeneration of the coalfield areas. Anglo-German perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Critcher, C; Schubert, K; Waddington, D [eds.

    1996-12-31

    Papers are presented under 6 main parts: the context; industrial regeneration through innovation, conversion and diversification; industrial regeneration through new investment by public and private sector partnership; fostering entrepreneurship through economic and psychological incentives; environmental issues - land reclamation and local regeneration; and education and training - reskilling the workforce.

  10. Regeneration of the coalfield areas. Anglo-German perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Critcher, C.; Schubert, K.; Waddington, D. [eds.

    1995-12-31

    Papers are presented under 6 main parts: the context; industrial regeneration through innovation, conversion and diversification; industrial regeneration through new investment by public and private sector partnership; fostering entrepreneurship through economic and psychological incentives; environmental issues - land reclamation and local regeneration; and education and training - reskilling the workforce.

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

    Science.gov (United States)

    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.

  12. Regenerator cross arm seal assembly

    Science.gov (United States)

    Jackman, Anthony V.

    1988-01-01

    A seal assembly for disposition between a cross arm on a gas turbine engine block and a regenerator disc, the seal assembly including a platform coextensive with the cross arm, a seal and wear layer sealingly and slidingly engaging the regenerator disc, a porous and compliant support layer between the platform and the seal and wear layer porous enough to permit flow of cooling air therethrough and compliant to accommodate relative thermal growth and distortion, a dike between the seal and wear layer and the platform for preventing cross flow through the support layer between engine exhaust and pressurized air passages, and air diversion passages for directing unregenerated pressurized air through the support layer to cool the seal and wear layer and then back into the flow of regenerated pressurized air.

  13. Thermodynamic analysis of a Stirling engine including regenerator dead volume

    Energy Technology Data Exchange (ETDEWEB)

    Puech, Pascal; Tishkova, Victoria [Universite de Toulouse, UPS, CNRS, CEMES, 29 rue Jeanne Marvig, F-31055 Toulouse (France)

    2011-02-15

    This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling engine with linear and sinusoidal variations of the volume. The regenerator in a Stirling engine is an internal heat exchanger allowing to reach high efficiency. We used an isothermal model to analyse the net work and the heat stored in the regenerator during a complete cycle. We show that the engine efficiency with perfect regeneration doesn't depend on the regenerator dead volume but this dead volume strongly amplifies the imperfect regeneration effect. An analytical expression to estimate the improvement due to the regenerator has been proposed including the combined effects of dead volume and imperfect regeneration. This could be used at the very preliminary stage of the engine design process. (author)

  14. Thinning in artificially regenerated young beech stands

    Directory of Open Access Journals (Sweden)

    Novák Jiří

    2015-12-01

    Full Text Available Although beech stands are usually regenerated naturally, an area of up to 5,000 ha year−1 is artificially regenerated by beech in the Czech Republic annually. Unfortunately, these stands often showed insufficient stand density and, consequently, lower quality of stems. Therefore, thinning methods developed for naturally regenerated beech stands are applicable with difficulties. The paper evaluates the data from two thinning experiments established in young artificially regenerated beech stands located in different growing conditions. In both experiments, thinning resulted in the lower amount of salvage cut in following years. Positive effect of thinning on periodic stand basal area increment and on periodic diameter increment of dominant trees was found in the beech stand located at middle elevations. On the other hand, thinning effects in mountain conditions were negligible. Thinning focusing on future stand quality cannot be commonly applied in artificially regenerated beech stands because of their worse initial quality and lower density. However, these stands show good growth and response to thinning, hence their management can be focused on maximising beech wood production.

  15. Performance analysis and experimental study of heat-source tower solution regeneration

    International Nuclear Information System (INIS)

    Liang, Caihua; Wen, Xiantai; Liu, Chengxing; Zhang, Xiaosong

    2014-01-01

    Highlights: • Theoretical analysis is performed on the characteristics of heat-source tower. • Experimental study is performed on various rules of the solution regeneration rate. • The characteristics of solution regeneration vary widely with different demands. • Results are useful for optimizing the process of solution regeneration. - Abstract: By analyzing similarities and difference between the solution regeneration of a heat-source tower and desiccant solution regeneration, this paper points out that solution regeneration of a heat-source tower has the characteristics of small demands and that a regeneration rate is susceptible to outdoor ambient environments. A theoretical analysis is performed on the characteristics of a heat-source tower solution in different outdoor environments and different regeneration modes, and an experimental study is performed on variation rules of the solution regeneration rate of a cross-flow heat-source tower under different inlet parameters and operating parameters. The experimental results show that: in the operating regeneration mode, as the air volume was increased from 123 m 3 h −1 to 550 m 3 h −1 , the system heat transfer amount increased from 0.42 kW to 0.78 kW, and the regeneration rate increased from 0.03 g s −1 to 0.19 g s −1 . Increasing the solution flow may increase the system heat transfer amount; however, the regeneration rate decreased to a certain extent. In the regeneration mode when the system is idle, as the air volume was increased from 136 m 3 h −1 to 541 m 3 h −1 , the regeneration rate increased from 0.03 g s −1 to 0.1 g s −1 . The regeneration rate almost remained unchanged around 0.07 g s −1 as the solution flow is increased. In the regeneration mode with auxiliary heat when the system is idle, increasing the air volume and increasing the solution flow required more auxiliary heat, thereby improving the solution regeneration rate. As the auxiliary heat was increased from 0.33 k

  16. Silymarin Accelerates Liver Regeneration after Partial Hepatectomy

    Directory of Open Access Journals (Sweden)

    Jia-Ping Wu

    2015-01-01

    Full Text Available Partial hepatectomy (PHx is a liver regeneration physiological response induced to maintain homeostasis. Liver regeneration evolved presumably to protect wild animals from catastrophic liver loss caused by toxins or tissue injury. Silymarin (Sm ability to stimulate liver regeneration has been an object of curiosity for many years. Silymarin has been investigated for use as an antioxidant and anticarcinogen. However, its use as a supportive treatment for liver damage is elusive. In this study, we fed silymarin (Sm, 25 mg/kg to male Sprague-Dawley rats for 7 weeks. Surgical 2/3 PHx was then conducted on the rats at 6 hrs, 24 hrs, and 72 hrs. Western blot and RT-PCR were conducted to detect the cell cycle activities and silymarin effects on hepatic regeneration. The results showed that silymarin enhanced liver regeneration by accelerating the cell cycle in PHx liver. Silymarin led to increased G1 phase (cyclin D1/pRb, S phase (cyclin E/E2F, G2 phase (cyclin B, and M phase (cyclin A protein and mRNA at 6 hrs, 24 hrs, and 72 hrs PHx. HGF, TGFα, and TGFβ1 growth factor expressions were also enhanced. We suggest that silymarin plays a crucial role in accelerated liver regeneration after PHx.

  17. Parathyroid hormone related to bone regeneration in grafted and nongrafted tooth extraction sockets in rats.

    Science.gov (United States)

    Kuroshima, Shinichiro; Al-Salihi, Zeina; Yamashita, Junro

    2013-02-01

    The quality and quantity of bone formed in tooth extraction sockets impact implant therapy. Therefore, the establishment of a new approach to enhance bone formation and to minimize bone resorption is important for the success of implant therapy. In this study, we investigated whether intermittent parathyroid hormone (PTH) therapy enhanced bone formation in grafted sockets. Tooth extractions of the maxillary first molars were performed in rats, and the sockets were grafted with xenograft. Intermittent PTH was administered either for 7 days before extractions, for 14 days after extractions, or both. The effect of PTH therapy on bone formation in the grafted sockets was assessed using microcomputed tomography at 14 days after extractions. PTH therapy for 7 days before extractions was not effective to augment bone fill, whereas PTH therapy for 14 days after operation significantly augmented bone formation in the grafted sockets. Intermittent PTH therapy starting right after tooth extractions significantly enhanced bone fill in the grafted sockets, suggesting that PTH therapy can be a strong asset for the success of the ridge preservation procedure.

  18. Centroacinar cells: At the center of pancreas regeneration.

    Science.gov (United States)

    Beer, Rebecca L; Parsons, Michael J; Rovira, Meritxell

    2016-05-01

    The process of regeneration serves to heal injury by replacing missing cells. Understanding regeneration can help us replace cell populations lost during disease, such as the insulin-producing β cells lost in diabetic patients. Centroacinar cells (CACs) are a specialized ductal pancreatic cell type that act as progenitors to replace β cells in the zebrafish. However, whether CACs contribute to β-cell regeneration in adult mammals remains controversial. Here we review the current understanding of the role of CACs as endocrine progenitors during regeneration in zebrafish and mammals. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Plant Regeneration and Genetic Transformation in Eggplant ...

    African Journals Online (AJOL)

    Dr Harmander Gill

    2014-02-05

    Feb 5, 2014 ... Review. Plant regeneration in eggplant (Solanum melongena L.): A review ... and development of somatic hybrids, efficient plant regeneration ... was first reported in eggplant from immature seed embryos .... Hormone free MS.

  20. [Platelet rich plasma (PRP): potentialities and techniques of extraction].

    Science.gov (United States)

    Pacifici, L; Casella, F; Maggiore, C

    2002-01-01

    This paper describes the various techniques of platelet-rich plasma (PRP) extraction codified in recent years and their use potential is evaluated. PRP is one of the techniques with which at the moment it is attempted to modulate and facilitate the cure of a wound. The use of PRP is based on the theoretical premise that by concentrating platelets the effects of the growth factors (PDGF, TGF-beta, IGF-I and -II) so released will be increased. Marx's original technique is described above all. This prescribes the sampling of a unit of blood (450-500 ml) and the use of a cell separator. We then analysed the technique of Marx and Hannon in which the quantity of blood sampled is reduced to 150 ml, and the two simplified techniques of the Sacchi and Bellanda group. Finally, a new PRP extraction technique is described. We conclude that platelet gel allows access to autologous growth factors which by definition are neither toxic nor immunogenic and are capable of accelerating the normal processes of bone regeneration. PRP can thus be considered a useful instrument for increasing the quality and final quantity of regenerated bone in oral and maxillo-facial surgery operations.

  1. Periodontal regeneration around natural teeth.

    Science.gov (United States)

    Garrett, S

    1996-11-01

    1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

  2. Axonal Regeneration in Mammals with Spinal Cord Injury

    Science.gov (United States)

    1983-09-14

    Cajal, S. 1905. Notas preventivas sobre la degeneracion y regeneracion las vias nerviosos centrales . Trab. Lab. Invest. Biol. Univ. Madrid, 4: 295-301...S. 1914. Degeneracion y Regeneration del Sistema Nervioso , Vol. 1, 2. (Nicolas Moya, Madrid), Ramon y Cajal, S. 1928. Degeneration and Regeneration...field of central nervous system (CNS) regeneration research. These developments have revealed important aspects regarding the histology and

  3. The regeneration of polluted active carbon by radiation techniques

    International Nuclear Information System (INIS)

    Bao Borong; Wu Minghong; Hu Longxin; Zhou Riumin; Zhu Jinliang

    1998-01-01

    In this paper, we investigated the regeneration of polluted active carbon from monosodium glutamate factory by combination of radiation and acid-alkali chemical techniques. The experimental results show that the polluted active carbon will be highly regenerated on the conditions of process concentration 3%, process time 0.5 hour and the adjustment process concentration 2%, time 0.5 hour, radiation dose 5kGy. As regeneration times increase, the regenerated active carbon behaves with good repetition and stable property

  4. Improved modelling of a parallel plate active magnetic regenerator

    International Nuclear Information System (INIS)

    Engelbrecht, K; Nielsen, K K; Bahl, C R H; Tušek, J; Kitanovski, A; Poredoš, A

    2013-01-01

    Much of the active magnetic regenerator (AMR) modelling presented in the literature considers only the solid and fluid domains of the regenerator and ignores other physical effects that have been shown to be important, such as demagnetizing fields in the regenerator, parasitic heat losses and fluid flow maldistribution in the regenerator. This paper studies the effects of these loss mechanisms and compares theoretical results with experimental results obtained on an experimental AMR device. Three parallel plate regenerators were tested, each having different demagnetizing field characteristics and fluid flow maldistributions. It was shown that when these loss mechanisms are ignored, the model significantly over predicts experimental results. Including the loss mechanisms can significantly change the model predictions, depending on the operating conditions and construction of the regenerator. The model is compared with experimental results for a range of fluid flow rates and cooling loads. (paper)

  5. Competence and regulatory interactions during regeneration in plants

    Directory of Open Access Journals (Sweden)

    Ajai Joseph Pulianmackal

    2014-04-01

    Full Text Available The ability to regenerate is widely exploited by multitudes of organisms ranging from unicellular bacteria to multicellular plants for their propagation and repair. But the levels of competence for regeneration vary from species to species. While variety of living cells of a plant display regeneration ability, only a few set of cells maintain their stemness in mammals. This highly pliable nature of plant cells in-terms of regeneration can be attributed to their high developmental plasticity. De novo organ initiation can be relatively easily achieved in plants by proper hormonal regulations. Elevated levels of plant hormone auxin induces the formation of proliferating mass of pluripotent cells called callus, which predominantly express lateral root meristem markers and hence is having an identity similar to lateral root primordia. Organ formation can be induced from the callus by modulating the ratio of hormones. An alternative for de novo organogenesis is by the forced expression of plant specific transcription factors. The mechanisms by which plant cells attain competence for regeneration on hormonal treatment or forced expression remain largely elusive. Recent studies have provided some insight into how the epigenetic modifications in plants affect this competence. In this review we discuss the present understanding of regenerative biology in plants and scrutinize the future prospectives of this topic. While discussing about the regeneration in the sporophyte of angiosperms which is well studied, here we outline the regenerative biology of the gametophytic phase and discuss about various strategies of regeneration that have evolved in the domain of life so that a common consensus on the entire process of regeneration can be made.

  6. Exploring the efficiency potential for an active magnetic regenerator

    DEFF Research Database (Denmark)

    Eriksen, Dan; Engelbrecht, Kurt; Haffenden Bahl, Christian Robert

    2016-01-01

    A novel rotary state of the art active magnetic regenerator refrigeration prototype was used in an experimental investigation with special focus on efficiency. Based on an applied cooling load, measured shaft power, and pumping power applied to the active magnetic regenerator, a maximum second-la...... and replacing the packed spheres with a theoretical parallel plate regenerator. Furthermore, significant potential efficiency improvements through optimized regenerator geometries are estimated and discussed......., especially for the pressure drop, significant improvements can be made to the machine. However, a large part of the losses may be attributed to regenerator irreversibilities. Considering these unchanged, an estimated upper limit to the second-law efficiency of 30% is given by eliminating parasitic losses...

  7. Mammalian Cochlear Hair Cell Regeneration and Ribbon Synapse Reformation

    Directory of Open Access Journals (Sweden)

    Xiaoling Lu

    2016-01-01

    Full Text Available Hair cells (HCs are the sensory preceptor cells in the inner ear, which play an important role in hearing and balance. The HCs of organ of Corti are susceptible to noise, ototoxic drugs, and infections, thus resulting in permanent hearing loss. Recent approaches of HCs regeneration provide new directions for finding the treatment of sensor neural deafness. To have normal hearing function, the regenerated HCs must be reinnervated by nerve fibers and reform ribbon synapse with the dendrite of spiral ganglion neuron through nerve regeneration. In this review, we discuss the research progress in HC regeneration, the synaptic plasticity, and the reinnervation of new regenerated HCs in mammalian inner ear.

  8. Mechanisms of lymphatic regeneration after tissue transfer.

    Directory of Open Access Journals (Sweden)

    Alan Yan

    2011-02-01

    Full Text Available Lymphedema is the chronic swelling of an extremity that occurs commonly after lymph node resection for cancer treatment. Recent studies have demonstrated that transfer of healthy tissues can be used as a means of bypassing damaged lymphatics and ameliorating lymphedema. The purpose of these studies was to investigate the mechanisms that regulate lymphatic regeneration after tissue transfer.Nude mice (recipients underwent 2-mm tail skin excisions that were either left open or repaired with full-thickness skin grafts harvested from donor transgenic mice that expressed green fluorescent protein in all tissues or from LYVE-1 knockout mice. Lymphatic regeneration, expression of VEGF-C, macrophage infiltration, and potential for skin grafting to bypass damaged lymphatics were assessed.Skin grafts healed rapidly and restored lymphatic flow. Lymphatic regeneration occurred beginning at the peripheral edges of the graft, primarily from ingrowth of new lymphatic vessels originating from the recipient mouse. In addition, donor lymphatic vessels appeared to spontaneously re-anastomose with recipient vessels. Patterns of VEGF-C expression and macrophage infiltration were temporally and spatially associated with lymphatic regeneration. When compared to mice treated with excision only, there was a 4-fold decrease in tail volumes, 2.5-fold increase in lymphatic transport by lymphoscintigraphy, 40% decrease in dermal thickness, and 54% decrease in scar index in skin-grafted animals, indicating that tissue transfer could bypass damaged lymphatics and promote rapid lymphatic regeneration.Our studies suggest that lymphatic regeneration after tissue transfer occurs by ingrowth of lymphatic vessels and spontaneous re-connection of existing lymphatics. This process is temporally and spatially associated with VEGF-C expression and macrophage infiltration. Finally, tissue transfer can be used to bypass damaged lymphatics and promote rapid lymphatic regeneration.

  9. Composite cell sheet for periodontal regeneration: crosstalk between different types of MSCs in cell sheet facilitates complex periodontal-like tissue regeneration.

    Science.gov (United States)

    Zhang, Hao; Liu, Shiyu; Zhu, Bin; Xu, Qiu; Ding, Yin; Jin, Yan

    2016-11-14

    Tissue-engineering strategies based on mesenchymal stem cells (MSCs) and cell sheets have been widely used for periodontal tissue regeneration. However, given the complexity in periodontal structure, the regeneration methods using a single species of MSC could not fulfill the requirement for periodontal regeneration. We researched the interaction between the periodontal ligament stem cells (PDLSCs) and jaw bone marrow-derived mesenchymal stem cells (JBMMSCs), and constructed a composite cell sheet comprising both of the above MSCs to regenerate complex periodontium-like structures in nude mice. Our results show that by co-culturing PDLSCs and JBMMSCs, the expressions of bone and extracellular matrix (ECM)-related genes and proteins were significantly improved in both MSCs. Further investigations showed that, compared to the cell sheet using PDLSCs or JBMMSCs, the composite stem cell sheet (CSCS), which comprises these two MSCs, expressed higher levels of bone- and ECM-related genes and proteins, and generated a composite structure more similar to the native periodontal tissue physiologically in vivo. In conclusion, our results demonstrate that the crosstalk between PDLSCs and JBMMSCs in cell sheets facilitate regeneration of complex periodontium-like structures, providing a promising new strategy for physiological and functional regeneration of periodontal tissue.

  10. Modelling and comparison studies of packed screen regenerators for active magnetocaloric refrigeration

    DEFF Research Database (Denmark)

    Lei, Tian; Engelbrecht, Kurt; Nielsen, K. K.

    2011-01-01

    In active magnetic regeneration (AMR) systems, not only the magnetocaloric properties of materials, but also the regenerator geometry plays an important role in the system performance. Packed sphere regenerators are often employed in existing prototypes, however, the characteristics such as relat...... is improved and applied to simulate the regenerators. The performance of the new regenerators is studied and compared with that of the packed sphere regenerators. Possible fabrication methods of the packed screen regenerators are also discussed....

  11. Modelling and comparison studies of packed screen regenerators for active magnetocaloric refrigeration

    DEFF Research Database (Denmark)

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein

    2014-01-01

    In active magnetic regeneration (AMR) systems, not only the magnetocaloric properties of materials, but also the regenerator geometry plays an important role in the system performance. Packed sphere regenerators are often employed in existing prototypes, however, the characteristics such as relat...... is improved and applied to simulate the regenerators. The performance of the new regenerators is studied and compared with that of the packed sphere regenerators. Possible fabrication methods of the packed screen regenerators are also discussed....

  12. Microwave regeneration of molecular sieves

    International Nuclear Information System (INIS)

    Singh, V.P.

    1984-05-01

    Molecular sieve driers have been included in the design of tritium handling systems for fusion reactors. In these systems there is a need to maintain extremely low exit dew points from the driers as well as a capability to rapidly reduce tritium concentrations following an accident. The required capacity of the driers is very high. The conventional method of regenerating these sieves after a water adsorption cycle is with hot air. However, because water is rapidly heated by microwave energy, this technology may be suitable for decreasing the bed regeneration time and hence may allow reduced capital and operating costs associated with a smaller bed. The present study was conducted to obtain preliminary information on the technical feasibility of regenerating molecular sieves with microwave energy. The study concentrated on Type 4A molecular sieve with a few tests on Type 13X sieve and also a silica gel adsorbent

  13. Notochord-derived hedgehog is essential for tail regeneration in Xenopus tadpole.

    Science.gov (United States)

    Taniguchi, Yuka; Watanabe, Kenji; Mochii, Makoto

    2014-06-18

    Appendage regeneration in amphibians is regulated by the combinatorial actions of signaling molecules. The requirement of molecules secreted from specific tissues is reflected by the observation that the whole process of regeneration can be inhibited if a certain tissue is removed from the amputated stump. Interestingly, urodeles and anurans show different tissue dependencies during tail regeneration. The spinal cord is essential for tail regeneration in urodele but not in anuran larva, whereas the notochord but not the spinal cord is essential for tail regeneration in anuran tadpoles. Sonic hedgehog is one of the signaling molecules responsible for such phenomenon in axolotl, as hedgehog signaling is essential for overall tail regeneration and sonic hedgehog is exclusively expressed in the spinal cord. In order to know whether hedgehog signaling is involved in the molecular mechanism underlying the inconsistent tissue dependency for tail regeneration between anurans and urodeles, we investigated expression of hedgehog signal-related genes in the regenerating tail of Xenopus tadpole and examined the effect of the hedgehog signal inhibitor, cyclopamine, on the tail regeneration. In Xenopus, sonic hedgehog is expressed exclusively in the notochord but not in the spinal cord of the regenerate. Overall regeneration was severely impaired in cyclopamine-treated tadpoles. Notochord maturation in the regenerate, including cell alignment and vacuolation, and myofiber formation were inhibited. Proliferation of spinal cord cells in the neural ampulla and of mesenchymal cells was also impaired. As in the axolotl, hedgehog signaling is required for multiple steps in tail regeneration in the Xenopus tadpole, although the location of the Shh source is quite different between the two species. This difference in Shh localization is the likely basis for the differing tissue requirement for tail regeneration between urodeles and anurans.

  14. Human dental pulp stem cells with highly angiogenic and neurogenic potential for possible use in pulp regeneration.

    Science.gov (United States)

    Nakashima, Misako; Iohara, Koichiro; Sugiyama, Masahiko

    2009-01-01

    Dental caries is a common public health problem, causing early loss of dental pulp and resultant tooth loss. Dental pulp has important functions to sustain teeth providing nutrient and oxygen supply, innervation, reactionary/reparative dentin formation and immune response. Regeneration of pulp is an unmet need in endodontic therapy, and angiogenesis/vasculogenesis and neurogenesis are critical for pulp regeneration. Permanent and deciduous pulp tissue is easily available from teeth after extraction without ethical issues and has potential for clinical use. In this review, we introduce some stem cell subfractions, CD31(-)/CD146(-) SP cells and CD105(+) cells with high angiogenic and neurogenic potential, derived from human adult dental pulp tissue. Potential utility of these cells is addressed as a source of cells for treatment of cerebral and limb ischemia and pulp inflammation complete with angiogenesis and vasculogenesis.

  15. Redox Control of Skeletal Muscle Regeneration.

    Science.gov (United States)

    Le Moal, Emmeran; Pialoux, Vincent; Juban, Gaëtan; Groussard, Carole; Zouhal, Hassane; Chazaud, Bénédicte; Mounier, Rémi

    2017-08-10

    Skeletal muscle shows high plasticity in response to external demand. Moreover, adult skeletal muscle is capable of complete regeneration after injury, due to the properties of muscle stem cells (MuSCs), the satellite cells, which follow a tightly regulated myogenic program to generate both new myofibers and new MuSCs for further needs. Although reactive oxygen species (ROS) and reactive nitrogen species (RNS) have long been associated with skeletal muscle physiology, their implication in the cell and molecular processes at work during muscle regeneration is more recent. This review focuses on redox regulation during skeletal muscle regeneration. An overview of the basics of ROS/RNS and antioxidant chemistry and biology occurring in skeletal muscle is first provided. Then, the comprehensive knowledge on redox regulation of MuSCs and their surrounding cell partners (macrophages, endothelial cells) during skeletal muscle regeneration is presented in normal muscle and in specific physiological (exercise-induced muscle damage, aging) and pathological (muscular dystrophies) contexts. Recent advances in the comprehension of these processes has led to the development of therapeutic assays using antioxidant supplementation, which result in inconsistent efficiency, underlying the need for new tools that are aimed at precisely deciphering and targeting ROS networks. This review should provide an overall insight of the redox regulation of skeletal muscle regeneration while highlighting the limits of the use of nonspecific antioxidants to improve muscle function. Antioxid. Redox Signal. 27, 276-310.

  16. Polymorphic regenerated silk fibers assembled through bioinspired spinning.

    Science.gov (United States)

    Ling, Shengjie; Qin, Zhao; Li, Chunmei; Huang, Wenwen; Kaplan, David L; Buehler, Markus J

    2017-11-09

    A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.

  17. Recloning of regenerated plantlets from elite oil palm ( Elaeis ...

    African Journals Online (AJOL)

    Plant regeneration in oil palm cv. Tenera via somatic embryogenesis was conducted using regenerated plantlets as an explant source. Explants from different positions – apex, middle and basal segments of regenerated plantlets – were cultured in N6 medium supplemented with 100, 120 and 140 mg/L 2 ...

  18. The effect of tapering on a magnetocaloric regenerator bed

    DEFF Research Database (Denmark)

    Dallolio, Stefano; Lei, Tian; Engelbrecht, Kurt

    2017-01-01

    . Therefore, this paper investigates the effect of the tapering of the regenerators, which exhibit better air-gap utilization. Several simulations using a 1D AMR model were run to study the performance of the tapered regenerator, and the results were compared to the case of the straight regenerator bed...

  19. My Regeneration:

    DEFF Research Database (Denmark)

    Carter, Dale

    2017-01-01

    and cultural referents shows that it offers an index to the album. Using its frontier setting and a variety of sacred and secular myths, symbols and icons, ‘Heroes and Villains,’ like Smile as a whole, offers historically-informed visions of national decline, crisis and regeneration that are at once critical...

  20. The role of neurotrophic factors in nerve regeneration.

    Science.gov (United States)

    Gordon, Tessa

    2009-02-01

    This review considers the 2 sources of neurotrophic factors in the peripheral nervous system (PNS), the neurons and the nonneuronal cells in the denervated distal nerve stumps, and their role in axon regeneration. Morphological assessment of regenerative success in response to administration of exogenous growth factors after nerve injury and repair has indicated a role of the endogenous neurotrophic factors from Schwann cells in the distal nerve stump. However, the increased number of axons may reflect more neurons regenerating their axons and/or increased numbers of axon sprouts from the same number of neurons. Using fluorescent dyes to count neurons that regenerated their axons across a suture site and into distal nerve stumps, brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) were found not to increase the number of neurons that regenerated their axons after immediate nerve repair. Nevertheless, the factors did reverse the deleterious effect of delayed nerve repair, indicating that the axons that regenerate into the distal nerve stump normally have access to sufficient levels of endogenous neurotrophic factors to sustain their regeneration, while neurons that do not have access to these factors require exogenous factors to sustain axon regeneration. Neurons upregulate neurotrophic factors after axotomy. The upregulation is normally slow, beginning after 7 days and occurring in association with a protracted period of axonal regeneration in which axons grow out from the proximal nerve stump across a suture site over a period of 1 month in rodents. This staggered axon regeneration across the suture site is accelerated by a 1-hour period of low-frequency electrical stimulation that simultaneously accelerates the expression of BDNF and its trkB receptor in the neurons. Elevation of the level of BDNF after 2 days to > 3 times that found in unstimulated neurons was accompanied by elevation of the level of cAMP and followed by

  1. Org-1-dependent lineage reprogramming generates the ventral longitudinal musculature of the Drosophila heart.

    Science.gov (United States)

    Schaub, Christoph; März, Johannes; Reim, Ingolf; Frasch, Manfred

    2015-02-16

    Only few examples of transdifferentiation, which denotes the conversion of one differentiated cell type to another, are known to occur during normal development, and more often, it is associated with regeneration processes. With respect to muscles, dedifferentiation/redifferentiation processes have been documented during post-traumatic muscle regeneration in blastema of newts as well as during myocardial regeneration. As shown herein, the ventral longitudinal muscles of the adult Drosophila heart arise from specific larval alary muscles in a process that represents the first known example of syncytial muscle transdifferentiation via dedifferentiation into mononucleate myoblasts during normal development. We demonstrate that this unique process depends on the reinitiation of a transcriptional program previously employed for embryonic alary muscle development, in which the factors Org-1 (Drosophila Tbx1) and Tailup (Drosophila Islet1) are key components. During metamorphosis, the action of these factors is combined with cell-autonomous inputs from the ecdysone steroid and the Hox gene Ultrabithorax, which provide temporal and spatial specificity to the transdifferentiation events. Following muscle dedifferentiation, inductive cues, particularly from the remodeling heart tube, are required for the redifferentiation of myoblasts into ventral longitudinal muscles. Our results provide new insights into mechanisms of lineage commitment and cell-fate plasticity during development. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Selective chelation-supercritical fluid extraction of metal ions from waste materials

    International Nuclear Information System (INIS)

    Wai, C.N.; Laintz, K.E.; Yonker, C.R.

    1993-01-01

    The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

  3. About tendon tissue regeneration in experimental radiation disease

    Energy Technology Data Exchange (ETDEWEB)

    Popov, D; Trichkova, P

    1976-01-01

    Under the conditions of experimental acute radiation disease the authors study the tendon tissue regeneration after suture of the lateral part of the gastrocnemius muscle tendon. Tendon auto and alloplasty were applied. In four postoperative periods the histological features are described in details as well as the characteristic phenomena observed during the regeneration influenced to a considerable degree by the irradiation. Round cell infiltration, large necrotic zones, erythrocyte infiltrations as well as predominance of non-specific tendon regeneration long after the surgery characterize the recovery period of the traumatically damaged tendon, nevertheless that at the end there is real tendon regeneration even though in a longer period in comparison with the controls (non-irradiated animals).

  4. [Age factor in eye regeneration of the gastropod mollusk Achatina fulica].

    Science.gov (United States)

    Tartakovskaia, O S; Borisenko, S L; Zhukov, V V

    2003-01-01

    The dependence of the ability to regenerate the eye on the age of experimental animals was studied in the snail Achatina fulica. The degree of regeneration was estimated by light-microscopic and electrophysiological methods and by analyzing the motor response to visual stimuli. In older age groups, the number of regenerated eye-bearing tentacles decreased, whereas the period of regeneration increased. The regenerated eyes of the snails operated at the age of more than two months remained smaller than normal eyes even after six months. Regeneration of the distal part of the optic nerve was observed, and the regenerated eyes recovered the ability to respond to stimulation by light. In the electroretinogram, the responses of the regenerated eye, compared to the control, were characterised by a lower amplitude and longer repolarization and refractory periods. Manifestations of the motor response to visual stimuli in the young snails with regenerating eyes could be regarded as evidence for the recovery of connection between the organ of sight and the central ganglia.

  5. Development of a Novel Degradation-Controlled Magnesium-Based Regeneration Membrane for Future Guided Bone Regeneration (GBR Therapy

    Directory of Open Access Journals (Sweden)

    Da-Jun Lin

    2017-11-01

    Full Text Available This study aimed to develop and evaluate the ECO-friendly Mg-5Zn-0.5Zr (ECO505 alloy for application in dental-guided bone regeneration (GBR. The microstructure and surface properties of biomedical Mg materials greatly influence anti-corrosion performance and biocompatibility. Accordingly, for the purpose of microstructure and surface modification, heat treatments and surface coatings were chosen to provide varied functional characteristics. We developed and integrated both an optimized solution heat-treatment condition and surface fluoride coating technique to fabricate a Mg-based regeneration membrane. The heat-treated Mg regeneration membrane (ARRm-H380 and duplex-treated regeneration membrane group (ARRm-H380-F24 h were thoroughly investigated to characterize the mechanical properties, as well as the in vitro corrosion and in vivo degradation behaviors. Significant enhancement in ductility and corrosion resistance for the ARRm-H380 was obtained through the optimized solid-solution heat treatment; meanwhile, the corrosion resistance of ARRm-H380-F24 h showed further improvement, resulting in superior substrate integrity. In addition, the ARRm-H380 provided the proper amount of Mg-ion concentration to accelerate bone growth in the early stage (more than 80% new bone formation. From a specific biomedical application point of view, these research results point out a successful manufacturing route and suggest that the heat treatment and duplex treatment could be employed to offer custom functional regeneration membranes for different clinical patients.

  6. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  7. Demagnetizing fields in active magnetic regenerators

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Bahl, Christian R.H.; Smith, Anders

    2014-01-01

    A magnetic material in an externally applied magnetic field will in general experience a spatially varying internal magnetic field due to demagnetizing effects. When the performance of active magnetic regenerators (AMRs) is evaluated using numerical models the internal field is often assumed...... is in general both a function of the overall shape of the regenerator and its morphology (packed particles, parallel plates etc.) as well as the magnetization of the material. Due to the pronounced temperature dependence of the magnetization near the Curie temperature, the demagnetization field is also...... temperature dependent. We propose a relatively straightforward method to correct sufficiently for the demagnetizing field in AMR models. We discuss how the demagnetizing field behaves in regenerators made of packed spheres under realistic operation conditions....

  8. Preparation and characterisation of Punica granatum pericarp aqueous extract loaded chitosan-collagen-starch membrane: role in wound healing process.

    Science.gov (United States)

    Amal, B; Veena, B; Jayachandran, V P; Shilpa, Joy

    2015-05-01

    Engineered scaffolds made from natural biomaterials are crucial elements in tissue engineering strategies. In this study, biological scaffold like chitosan-collagen-starch membrane (CCSM) loaded with the antibacterial agent, Punica granatum pericarp aqueous extract was explored for enhanced regeneration of epithelial tissue during wound healing. Collagen was extracted from Rachycentron canadum fish skin. Membranous scaffold was prepared by mixing collagen, starch and chitosan in a fixed proportion, loaded with aqueous extract of P. granatum and its anti-pseudomonal activity was studied. Morphological characterization by SEM and mechanical property like tensile strength of the membrane were studied. Excision wound of 2 cm(2) size was induced in Guinea pig and the effect of P. granatum extract loaded CCSM in wound healing was studied. The SEM image showed deep pores in the membrane and also possessed good tensile strength. Wound surface area was reduced prominently in the experimental group with P. granatum extract loaded CCSM when compared to the group with unloaded membrane and the one with no membrane. Punica granatum extract loaded CCSM has antipseudomonal property and supported enhanced epithelial cell proliferation without leaving a scar after wound healing. This has significant therapeutic application in membranous scaffold mediated skin repair and regeneration.

  9. Performance investigation on the ultrasonic atomization liquid desiccant regeneration system

    International Nuclear Information System (INIS)

    Yang, Zili; Zhang, Kaisheng; Hwang, Yunho; Lian, Zhiwei

    2016-01-01

    Highlights: • We applied ultrasonic atomization technology to boost liquid desiccant regeneration. • We established a novel UARS and made a thorough study on its performance. • We developed a performance prediction model for UARS and validated its accuracy. • The necessary regeneration temperature dropped significantly (4.4 °C) in UARS. • Energy consumption for regenerating desiccant was reduced greatly (60.4%) in UARS. - Abstract: Liquid desiccant dehumidification systems have accumulated considerable research interest in recent years for their great energy saving potential in buildings. Within the system, the regenerator recovering liquid desiccant plays a major role in its performance. When the ultrasonic atomization technology is applied to atomize the desiccant solution into numerous tiny droplets with diameters around 50 μm, the regeneration process could be greatly enhanced. To validate this approach, a novel ultrasonic atomization liquid desiccant regeneration system (UARS) was studied in this work. An Ideal Regeneration Model (IRM) was developed to predict the regeneration performance of the UARS. Additionally, thorough experiments were carried out to validate the model under different operating conditions of the desiccant solution and air stream. The model predicted values and the experimental results coincided, with the average deviation less than 7.9%. The performance of UARS was compared with other regeneration systems from the open literature, while a case study was conducted for the power consumption and energy saving potential of UARS. It was found that the ultrasonic atomization technology enabled utilization of lower-grade energy for desiccant regeneration with the regeneration temperature lowered as much as 4.4 °C. In addition, a considerable energy saving potential of up to 23.4% could be achieved by the UARS for regenerating per unit mass flow of desiccant solution, while the power consumption of the ultrasonic atomization system

  10. The head-regeneration transcriptome of the planarian Schmidtea mediterranea

    Science.gov (United States)

    2011-01-01

    Background Planarian flatworms can regenerate their head, including a functional brain, within less than a week. Despite the enormous potential of these animals for medical research and regenerative medicine, the mechanisms of regeneration and the molecules involved remain largely unknown. Results To identify genes that are differentially expressed during early stages of planarian head regeneration, we generated a de novo transcriptome assembly from more than 300 million paired-end reads from planarian fragments regenerating the head at 16 different time points. The assembly yielded 26,018 putative transcripts, including very long transcripts spanning multiple genomic supercontigs, and thousands of isoforms. Using short-read data from two platforms, we analyzed dynamic gene regulation during the first three days of head regeneration. We identified at least five different temporal synexpression classes, including genes specifically induced within a few hours after injury. Furthermore, we characterized the role of a conserved Runx transcription factor, smed-runt-like1. RNA interference (RNAi) knockdown and immunofluorescence analysis of the regenerating visual system indicated that smed-runt-like1 encodes a transcriptional regulator of eye morphology and photoreceptor patterning. Conclusions Transcriptome sequencing of short reads allowed for the simultaneous de novo assembly and differential expression analysis of transcripts, demonstrating highly dynamic regulation during head regeneration in planarians. PMID:21846378

  11. The effect of supercritical isobutane regeneration on the nature of hydrocarbons deposited on a USY zeolite catalyst utilized for isobutane/butene alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; Lucia M. Petkovic

    2004-11-01

    The chemical nature of hydrocarbons remaining on an ultrastable Y-zeolite (USY) utilized for liquid phase isobutane/butene alkylation reaction at 333 K and 1.1x107 Pa before and after supercritical isobutane regeneration (SFR) at 453 K and 1.1x107 Pa are presented. Catalyst samples were deactivated to different levels by running the alkylation reaction for different times on stream (TOS) and regenerated under flowing supercritical isobutane for 60 min. Nitrogen physisorption, temperature-programmed oxidation (TPO), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and ultraviolet-visible (UV-Vis) spectroscopy measurements suggested that the SFR process was effective in recovering catalyst surface area and micropore volume and that most coke precursors were removed from samples regenerated after short TOS, when the level of activity for trimethylpentanes (TMP) production was high. Samples that were allowed to react for longer TOS contained unsaturated hydrocarbons that, instead of being extracted by the supercritical fluid, dehydrogenated during the SFR process to produce more condensed species.

  12. Regeneration of Centella asiatica plants from non-embryogenic cell lines and evaluation of antibacterial and antifungal properties of regenerated calli and plants

    Directory of Open Access Journals (Sweden)

    Habib Darima

    2011-10-01

    Full Text Available Abstract Background The threatened plant Centella asiatica L. is traditionallyused for a number of remedies. In vitro plant propagation and enhanced metabolite production of active metabolites through biotechnological approaches has gained attention in recent years. Results Present study reveals that 6-benzyladenine (BA either alone or in combination with 1-naphthalene acetic acid (NAA supplemented in Murashige and Skoog (MS medium at different concentrations produced good quality callus from leaf explants of C. asiatica. The calli produced on different plant growth regulators at different concentrations were mostly embryogenic and green. Highest shoot regeneration efficiency; 10 shoots per callus explant, from non-embryogenic callus was observed on 4.42 μM BA with 5.37 μM NAA. Best rooting response was observed at 5.37 and 10.74 μM NAA with 20 average number of roots per explant. Calli and regenerated plants extracts inhibited bacterial growth with mean zone of inhibition 9-13 mm diameter when tested against six bacterial strains using agar well diffusion method. Agar tube dilution method for antifungal assay showed 3.2-76% growth inhibition of Mucor species, Aspergillus fumigatus and Fusarium moliniformes. Conclusions The present investigation reveals that non-embryogenic callus can be turned into embryos and plantlets if cultured on appropriate medium. Furthermore, callus from leaf explant of C. asiatica can be a good source for production of antimicrobial compounds through bioreactor.

  13. Multilayer Ceramic Regenerator Materials for 4 K Cooling

    International Nuclear Information System (INIS)

    Numazawa, T.; Kamiya, K.; Satoh, T.; Nozawa, H.; Yanagitani, T.

    2006-01-01

    The ceramics oxide magnetic materials have shown excellent properties for use as regenerator materials used in 4 K crycoolers. Currently four kinds of oxide magnetic materials GdVO4, GAP=GdAlO3, GOS=Gd2O2S and Tb2O2S are available for applications for regenerators or thermal anchors from 2 K to 8 K. This paper focused on controlling the heat capacity of the (GdxTb1-x)2O2S system to cover the refrigeration temperatures between 6 K and 8 K. A concept of multilayer regenerator material consisting of multicomponent magnetic materials has been proposed and investigated. Two-layer ceramic material including two kinds of magnetic materials (Gd0.1Tb0.9)2O2S+Tb2O2S was successfully fabricated in the form of regenerator particles with an average diameter of 0.25 mm. Measured heat capacity data showed that it had twin peaks relating to those of (Gd0.1Tb0.9)2O2S and Tb2O2S, and the entire curve became broader and wider. The mechanical properties of strength and hardness of the two-layer ceramic material were the same as other ceramic regenerator materials like GOS. Thus, it is concluded that the multilayer ceramic material is very useful to control the heat capacity of the regenerator particles. The cooling tests using the two-layer ceramic material with HoCu2 and GOS have been done to investigate the 2nd stage regenerator configuration

  14. Plant regeneration in wheat mature embryo culture

    African Journals Online (AJOL)

    Kamil Haliloğlu

    2011-11-09

    Nov 9, 2011 ... Success in genetic engineering of cereals depends on the callus formation and efficient plant regeneration system. Callus formation and plant regeneration of wheat mature embryos ... compiled by modification of methods previously mentioned in ..... of more and readily available nutrition than artificial cul-.

  15. Heat exchanger versus regenerator: A fundamental comparison

    NARCIS (Netherlands)

    Will, M.E.; Waele, de A.T.A.M.

    2005-01-01

    Irreversible processes in regenerators and heat exchangers limit the performance of cryocoolers. In this paper we compare the performance of cryocoolers, operating with regenerators and heat exchangers from a fundamental point of view. The losses in the two systems are calculated from the entropy

  16. Soil weathering agents are limited where deep tree roots are removed, even after decades of forest regeneration

    Science.gov (United States)

    Billings, S. A.; Richter, D. D., Jr.; Hirmas, D.; Lehmeier, C.; Bagchi, S.; Brecheisen, Z.; Sullivan, P. L.; Min, K.; Hauser, E.; Stair, R.; Flournoy, R.

    2017-12-01

    Deep roots pump reduced C deep into Earth's critical zone (CZ) as they grow and function. This action generates acid-forming CO2 and organic acids (OA) and fosters microbes that also produce these weathering agents. This phenomenon results in a regolith-weathering reaction front that propagates down with vertical root extension and water infiltration. Across old-growth hardwood, younger pine, and annual crop plots at the Calhoun Critical Zone Observatory, we tested the hypothesis that persistent absence of deep roots, a widespread anthropogenic phenomenon, reduces root- and microbially-mediated biogeochemical pools and fluxes important for weathering, even well below maximum root density. We also hypothesized that land use effects on deep soil biogeochemistry is evident even after decades of forest regeneration. Root abundance to 2 m declined with depth, and was greater in old-growth and regenerating forests than in crop plots at most depths. Old-growth soils also contain more roots than younger pine soils: between 30-45 and 70-80 cm depth, old-growth root abundances were greater than in regenerating forests, and old-growth soils exhibited root distributions with less severe declines with depth and harbored more root-associated bacteria than younger forests. Changing root abundances influenced concentrations of weathering agents. At 3 m, in situ soil [CO2] reached 6%, 4%, and 2% in old-growth, regenerating, and crop soils, respectively. Soil organic C (SOC) and extractable OC (EOC, an OA proxy) did not differ across land use, but at 4-5 m EOC/SOC was higher in old-growth compared to regenerating forests and crop soils (20.0±2.6 vs. 2.0±1.0%). We suggest that biogeochemistry deep beneath old-growth forests reflects greater root prevalence and propensity for generation of weathering agents, and that disturbance regimes inducing deep root mortality impose top-down signals relevant to weathering processes deep in Earth's CZ even after decades of forest regeneration.

  17. Aberrant regeneration of the third cranial nerve.

    Science.gov (United States)

    Shrestha, U D; Adhikari, S

    2012-01-01

    Aberrant regeneration of the third cranial nerve is most commonly due to its damage by trauma. A ten-month old child presented with the history of a fall from a four-storey building. She developed traumatic third nerve palsy and eventually the clinical features of aberrant regeneration of the third cranial nerve. The adduction of the eye improved over time. She was advised for patching for the strabismic amblyopia as well. Traumatic third nerve palsy may result in aberrant regeneration of the third cranial nerve. In younger patients, motility of the eye in different gazes may improve over time. © NEPjOPH.

  18. Public private co-operation in urban regeneration investment planning

    DEFF Research Database (Denmark)

    Jensen, Jesper Ole; Larsen, Jacob Norvig

    development. However, we believe that municipalities can become much better at attracting private investors and developers, partly because there is knowledge about the motives and backgrounds for the developers' engagement in the urban regeneration. Based on data from a number of case studies and interviews......Increasing renovation costs and ever more limited public funding for urban regeneration in combination with a political desire to stimulate the development of a sense of ownership in urban regeneration neighbourhoods has brought about a growing interest in attracting private sector funding...... with developers we argue that developers own networks are more likely to lead them to the urban regeneration areas, than knowledge of the urban regeneration itself. Also, the study reveals a mutual knowledge-gap between the municipal planners and developers; planners have limited knowledge of developers...

  19. Adaptation of regenerants of Vaccinium corymbosum L. and ...

    African Journals Online (AJOL)

    The benchmark analysis of the structured-functional particularities of regeneration ... the structured-functional organization regeneration (a mobile system) can be ... Key words: Aseptic culture, greenhouse, open ground, anatomical structure, ...

  20. Oxidative regeneration of Ni-Mo-gamma-Al/sub 2/O/sub 3/ catalysts used for hydrotreatment of coal-derived oil

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Yuji; Furimsky, Edward; Sato, Toshio; Shimada, Hiromichi; Matsubayashi, Nobuyuki; Nishijima, Akio

    1986-10-23

    In order to easily find the oxidative reaction characteristics of carbonaceous materials and sulfur deposited on the catalysts used for hydrogenation, oxidative regeneration behavior as studied with a fixed bed reactor, and the surfaces of the spent catalysts were analyzed by XPS to find the changes in form of active metals and sulfur on the catalysts. Ni-Mo-gamma-Al/sub 2/O/sub 3/ catalysts were used for hydrotreatment of primary coal-derived oil from Morwell coal. The spent catalysts were extracted by THF, dried and crushed into 100-200 mesh powder. The relation between catalyst regeneration temperature and CO/sub 2/ or SO/sub 2/, the relation between generated gas compositions and temperature in regeneration, and the activation energy of carbon and sulfur in the catalysts for oxidative reaction were indicated with data. As a result, it was found that a part of the active metals turned to sulfates by hydrotreatment and the residual sulfur existed in form of sulfate. ( 6 figs, 2 tabs, 4 refs )

  1. Regeneration characteristics of desiccant rotor with microwave and hot-air heating

    International Nuclear Information System (INIS)

    Kubota, Mitsuhiro; Hanada, Takuya; Yabe, Satoshi; Matsuda, Hitoki

    2013-01-01

    Microwave heating, because of its advantages of direct and rapid heating of materials, has the potential to be employed as a novel regeneration method of desiccant rotors in humidity conditioners. We proposed a combined regeneration process, which combines microwave heating and conventional hot-air heating. The system is expected to achieve high heating rate during an initial regeneration period by assisting water desorption using the additional energy of the microwave. In this study, the regeneration characteristics of a desiccant rotor were experimentally investigated under conditions of microwave heating, hot-air heating, and combined heating at various microwave powers and hot-air temperatures. The effectiveness of the combined regeneration was evaluated in terms of the regeneration ratio, the initial regeneration rate, the temperature distribution in the rotor, and finally in terms of the energy consumption. It was demonstrated that combined heating was effective at leveling non-uniform temperature distribution in the rotor. Combined heating achieved higher ratios and initial rates in regeneration compared to just microwave and hot-air heating. This result was obviously attributed to the additional input of microwave energy, resulting that average rotor temperature increased by microwave absorption of rotor. Moreover, it was also effective for enhancement of regeneration to level the temperature distribution in the rotor by combination of two heating methods with different heating mechanisms. Both the initial regeneration rate and the equilibrium regeneration ratio for combined heating were found to increase as the microwave power increased. A linear relationship was observed with respect to microwave power. From the viewpoint of energy consumption, it may be possible to apply combined and microwave heating to humidity control systems that switch between adsorption and regeneration in short cycle times, if the conversion and absorption efficiencies of the

  2. Adventitious shoots induction and plant regeneration from ...

    African Journals Online (AJOL)

    A highly efficient regeneration system is a prerequisite step for successful genetic transformation of watermelon cultivars (Citrullus lanatus L.). The objective of this study was to establish efficient in vitro plant regeneration for three watermelon cultivars. To achieve optimal conditions for adventitious shoot induction, the ...

  3. Straight-Pore Microfilter with Efficient Regeneration

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.; McCallum. Thomas J.; Schmitt, Edwin W.

    2010-01-01

    A novel, high-efficiency gas particulate filter has precise particle size screening, low pressure drop, and a simple and fast regeneration process. The regeneration process, which requires minimal material and energy consumption, can be completely automated, and the filtration performance can be restored within a very short period of time. This filter is of a novel material composite that contains the support structure and a novel coating.

  4. Chronological protein synthesis in regenerating rat liver.

    Science.gov (United States)

    He, Jinjun; Hao, Shuai; Zhang, Hao; Guo, Fuzheng; Huang, Lingyun; Xiao, Xueyuan; He, Dacheng

    2015-07-01

    Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, (35) S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through (35) S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5-5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Müller stem cell dependent retinal regeneration.

    Science.gov (United States)

    Chohan, Annu; Singh, Usha; Kumar, Atul; Kaur, Jasbir

    2017-01-01

    Müller Stem cells to treat ocular diseases has triggered enthusiasm across all medical and scientific communities. Recent development in the field of stem cells has widened the prospects of applying cell based therapies to regenerate ocular tissues that have been irreversibly damaged by disease or injury. Ocular tissues such as the lens and the retina are now known to possess cell having remarkable regenerative abilities. Recent studies have shown that the Müller glia, a cell found in all vertebrate retinas, is the primary source of new neurons, and therefore are considered as the cellular basis for retinal regeneration in mammalian retinas. Here, we review the current status of retinal regeneration of the human eye by Müller stem cells. This review elucidates the current status of retinal regeneration by Müller stem cells, along with major retinal degenerative diseases where these stem cells play regenerative role in retinal repair and replacement. Copyright © 2016. Published by Elsevier B.V.

  6. Regeneration of used activated carbon by electron beam irradiation

    International Nuclear Information System (INIS)

    Arai, H.; Hosono, M.; Zhu, G.; Miyata, T.

    1992-01-01

    The adsorbing power of granular activated carbons which adsorbed sodium laurylsulfate were most effectively recovered by irradiation of high energy electron beams in nitrogen stream, and the carbon was hardly lost by irradiation. The regeneration was induced mainly by microscopic heating of adsorption sites. Regeneration was also confirmed by adsorption endotherms. Regeneration cost was tentatively evaluated. (author)

  7. Traffic engineering and regenerator placement in GMPLS networks with restoration

    Science.gov (United States)

    Yetginer, Emre; Karasan, Ezhan

    2002-07-01

    In this paper we study regenerator placement and traffic engineering of restorable paths in Generalized Multipro-tocol Label Switching (GMPLS) networks. Regenerators are necessary in optical networks due to transmission impairments. We study a network architecture where there are regenerators at selected nodes and we propose two heuristic algorithms for the regenerator placement problem. Performances of these algorithms in terms of required number of regenerators and computational complexity are evaluated. In this network architecture with sparse regeneration, offline computation of working and restoration paths is studied with bandwidth reservation and path rerouting as the restoration scheme. We study two approaches for selecting working and restoration paths from a set of candidate paths and formulate each method as an Integer Linear Programming (ILP) prob-lem. Traffic uncertainty model is developed in order to compare these methods based on their robustness with respect to changing traffic patterns. Traffic engineering methods are compared based on number of additional demands due to traffic uncertainty that can be carried. Regenerator placement algorithms are also evaluated from a traffic engineering point of view.

  8. Chitosan Based Regenerated Cellulose Fibers Functionalized with Plasma and Ultrasound

    Directory of Open Access Journals (Sweden)

    Urška Vrabič Brodnjak

    2018-04-01

    Full Text Available The great potential of regenerated cellulose fibers, which offer excellent possibilities as a matrix for the design of bioactive materials, was the lead for our research. We focused on the surface modification of fibers to improve the sorption properties of regenerated cellulose and biocomposite regenerated cellulose/chitosan fibers, which are on the market. The purpose of our investigation was also the modification of regenerated cellulose fibers with the functionalization by chitosan as a means of obtaining similar properties to biocomposite regenerated cellulose/chitosan fibers on the market. Argon gas plasma was used for fiber surface activation and chitosan adsorption. Ultrasound was also used as a treatment procedure for the surface activation of regenerated cellulose fibers and treatment with chitosan. Analyses have shown that ultrasonic energy or plasma change the accessibility of free functional groups, structure and reactivity, especially in regenerated cellulose fibers. Changes that occurred in the morphology and in the structure of fibers were also reflected in their physical and chemical properties. Consequently, moisture content, sorption properties and water retention improved.

  9. Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective.

    Science.gov (United States)

    Huang, George T-J; Al-Habib, Mey; Gauthier, Philippe

    2013-03-01

    There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic.

  10. Untersuchungen zur Regeneration des Hinterendes bei Anaitides mucosa (Polychaeta, Phyllodocidae)

    Science.gov (United States)

    Röhrkasten, A.

    1983-06-01

    Caudal regeneration was investigated in decerebrate Anaitides mucosa and in brain-intact individuals. Both groups show an identical capacity to regenerate lost caudal segments. Furthermore there is no difference in males and females. Low temperature (5 °C) inhibits the regeneration of caudal segments, but it is necessary for normal oogenesis. Under conditions of high temperature (15 °C), caudal regeneration is very extensive. At the same time degeneration of most oocytes occurs.

  11. Planning and Implementation of Urban Regeneration

    DEFF Research Database (Denmark)

    Aunsborg, Christian; Sørensen, Michael Tophøj

    2008-01-01

    new statutory tools to handle the spatial transformation of urban regeneration areas. The paper examines the subsequent development of Danish planning legislation with the purpose of determining whether the present 'statutory toolbox' can be considered sufficient compared to the problems...... the regeneration challenge became an issue in the professional debate. The urban, economic and spatial problematics rising from structural development trends of society were subject to a committee work from 1999 through 2001. The work resulted in a number of recommendations comprising i.a. suggestions concerning...... and challenges emerging in practice. To evaluate the adequacy of the toolbox the paper draws on case studies on urban regeneration projects in three major Danish cities. The conclusion is that the legislative developments during the last five years must be considered very relevant to problem solving in practice...

  12. Pancreatic islet regeneration: Therapeutic potential, unknowns and controversy

    Directory of Open Access Journals (Sweden)

    Ingrid L. Cockburn

    2015-07-01

    Full Text Available Glucose homeostasis in mammals is primarily maintained by the insulin-secreting β-cells contained within pancreas-resident islets of Langerhans. Gross disruption of this glucose regulation as a result of pancreatic dysfunction frequently results in diabetes, which is currently a major health concern in South Africa, as well as globally. For many years, researchers have realised that the pancreas, and specifically the islets of Langerhans, have a regenerative capacity, as islet mass has frequently been shown to increase following induced pancreatic injury. Given that gross β-cell loss contributes significantly to the pathogenesis of both type 1 and type 2 diabetes, endogenous pancreatic islet regeneration has been investigated extensively as a potential β-cell replacement therapy for diabetes. From the extensive research conducted on pancreatic regeneration, opposing findings and opinions have arisen as to how, and more recently even if, pancreatic regeneration occurs following induced injury. In this review, we outline and discuss the three primary mechanisms by which pancreatic regeneration is proposed to occur: neogenesis, β-cell replication and transdifferentiation. We further explain some of the advanced techniques used in pancreatic regeneration research, and conclude that despite the technologically advanced research tools available to researchers today, the mechanisms governing pancreatic regeneration may remain elusive until more powerful techniques are developed to allow for real-time, live-cell assessment of morphology and gene expression within the pancreas.

  13. Nucleated regeneration of semiarid sclerophyllous forests close to remnant vegetation

    NARCIS (Netherlands)

    Fuentes-Castillo, T.; Miranda, A.; Rivera-Hutinel, A.; Smith-Ramirez, C.; Holmgren, M.

    2012-01-01

    Natural regeneration of mediterranean plant communities has proved difficult in all continents. In this paper we assess whether regeneration of sclerophyllous forests shows nucleated patterns indicative of a positive effect of vegetation remnants at the landscape level and compare the regeneration

  14. Evaluation Study Of Inhibition And Regeneration Characters For Substituted Anilines Extracted From Crude Oil

    Directory of Open Access Journals (Sweden)

    Dr. Mohammad Jamil Abd-Alghani

    2015-08-01

    Full Text Available Abstract Aniline derivatives containing carbonyl group in the side chain was extracted from crude oil received from Al- Dora refinery. The crude oil was dissolved in xylene 13 and extracted through a column containing activated cationic resin type Amberlyte 15 then eluted by absolute ethanol and identified by infra red spectroscopy then examined as antioxidant for lubricant oil stock 50. FT-IR spectroscopy for the lubricant oil was performed before employing in an internal combustion engine and 190 hrs after. It was seen that the FT-IR of the oxidized oil contains a new peak in the region 1700 1800 cm1 which is formed due to the oxidation of base oil which belongs to carbonyl group. The FT-IR specter for the formulated crude oil with a specific concentration of the extracted substituted aniline after applying the same conditions of oxidation 190 working hrs. in an internal combustion engine showed a minimum peak intensity at 1710 1770 cm-1 than that observed in FT-IR done in absence of extracted antioxidant. The values of induction periods in presence of 0.20 and 0.30 moll of the extracted sample in the lubricant oil at 393 K were 766 sec. 1630 sec. while in their absence was 55 sec.. The values of maximum rates of oxidation were 3.0x10-4 and 2.0x10-4 moll. sec. These values were still not arrived the value of maximum rate of oxidation for the lubricant oil 3.5 x10-4 mol.l.sec. The same study was applied on the universal antioxidant inhibitor 2 6-diter-butyl-4-methyl phenol phenolic type under the same conditions. The obtained induction periods were 150 290 sec. respectively. This means that the values of induction periods obtained by formulating the lubricant oil with the extracted aniline molecule were 7 times greater than do the 2 6- diter-butyl-4-methyl phenol molecule. From the literatures it is known that the value of stochiometric factor for inhibition f for 2 4 6-triisobutyl phenol is equal to 2 so as a result the value of stochiometric

  15. Fcγ receptor-mediated inflammation inhibits axon regeneration.

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

  16. CO2 regeneration performance enhancement by nanoabsorbents for energy conversion application

    International Nuclear Information System (INIS)

    Lee, Jung Hun; Lee, Jae Won; Kang, Yong Tae

    2016-01-01

    Graphical abstract: (a) Optical profiling image of the surface of copper after regeneration process in nanoabsorbents, Al 2 O 3 (45 nm, 0.01 vol%). (b) The number of regeneration sites by the nanoabsorbents. - Highlights: • CO 2 regeneration performance is enhanced by using Al 2 O 3 nanoabsorbents. • CO 2 regeneration process on the heating surface is visualized in nanoabsorbents. • Surface modification by nanoabsorbents has a greater effect than the nanoparticle size. • The mechanism of surface effect is the most plausible to explain the regeneration performance enhancement. - Abstract: Due to the recent increase in the consumption of energy and the use of fossil fuels, global warming has become a serious issue. To address this problem, CO 2 gas, which is the major element of the greenhouse gases, should be captured, regenerated and converted to useful fuels. The Integrated Gasification Combined Cycle (IGCC) and cement process generate large amount of CO 2 , which are controlled through pre-combustion capture. However, this method has a disadvantage because the system temperature should be decreased to −20 °C or lower. Therefore, the development of new absorbent is required to reduce the energy consumed for refrigeration. There is a study that improved the CO 2 absorption performance by adding Al 2 O 3 nanoparticles to methanol. However, studies on the regeneration of CO 2 in nanofluid absorbents (nanoabsorbents) are insufficient. Therefore, in this study, the CO 2 regeneration performance in Al 2 O 3 nanoabsorbents is evaluated. It is found that the regeneration performance of CO 2 is improved by 16% by using nanoabsorbents compared to methanol. Furthermore, the CO 2 regeneration characteristics of nanoabsorbents are analyzed by considering the detachment time of CO 2 bubbles from the surface, the cross-sectional area of CO 2 bubble, and the number of regeneration sites through the CO 2 regeneration and bubble visualization experiments. It is concluded

  17. Factors influencing callus induction and plant regeneration of ...

    African Journals Online (AJOL)

    ajl yemi

    2012-01-12

    ). Effect of basal medium on callus induction and plant regeneration. Three different kinds of basal mediums (MS, N6 and SH) were used to investigate their effects on callus induction and regeneration. Significant differences ...

  18. Impact of FCC regenerator design in the NOx emissions

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Hugo Borges; Sandes, Emanuel Freire; Gilbert, William Richard; Roncolatto, Rodolfo Eugenio; Gobbo, Rodrigo; Casavechia, Luiz Carlos; Candido, William Victor Carlos [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Bridi, Patricia Elaine [Possebon Engenharia, Sao Mateus do Sul, PR (Brazil)

    2012-07-01

    Fluid Catalytic Cracking (FCC) is the main point source of NOx in the refinery and it is responsible for at least 20% of the total NOx emissions from the refineries. The thermal NOx formation in the FCC regenerator is negligible. However, half of the feed nitrogen is converted to coke, and is burned in the regenerator. The majority of coke nitrogen is reduced to N2 and less than 10% is converted to NOx. This number may vary significantly with the oxygen excess in the flue gas and other operational conditions. With the purpose of evaluating the impact of different regenerator designs in NOx formation, several tests were carried out in the PETROBRAS FCC prototype unit. The test unit is equipped with adiabatic insulation and a CO boiler, allowing it to reproduce the heat balance of a commercial FCC and to operate either in full combustion or partial combustion. Two different designs of FCC regenerators were evaluated: single stage regenerator (the existing configuration) and two stage regenerator, with the catalyst bed divided into two sections by a structured packing baffle. It was observed in the tests that the combustion regime had a very strong effect on NOx formation. In full combustion, the effect of the FCC operating variables: excess oxygen, combustion promoter content in catalyst and regenerator design could be identified. The two stage configuration was capable of decreasing NOx emissions by 30%. In partial combustion, the effect of the CO-boiler variables on NOx emissions was overwhelming, but the use of the structured packing baffle was able to improve the catalyst regeneration.(author)

  19. PERFORMANCE ENHANCEMENT OF A MINIATURE STIRLING CRYOCOOLER WITH A MULTI MESH REGENERATOR DESIGN

    Directory of Open Access Journals (Sweden)

    KISHOR KUMAR V. V.

    2017-06-01

    Full Text Available A parametric study has been carried out using the software REGEN 3.3 to optimize the regenerator of a miniature Stirling cryocooler operating with a warm end temperature of 300 K and cold end temperature of 80 K. Regenerator designs which produce the maximum coefficient of performance (COP of the system is considered as an optimized regenerator. The length and diameter of the regenerator were fixed from the cooler system requirements. Single mesh regenerators made of 200, 250, 300, 400 and 450 Stainless Steel wire meshes were considered and the optimum phase angle and mesh size were obtained. A maximum COP of 0.1475 was obtained for 300 mesh regenerator at 70° phase angle. Then multi mesh regenerators were considered with finer mesh on the cold end and coarser mesh on the hot end. The optimum size and length of each mesh in the multi mesh regenerator and the optimum phase angle were calculated. The maximum COP of 0.156 was obtained for 200 300-400 multi mesh regenerator at 70° phase angle. The COP and net refrigeration obtained for an optimized multi mesh regenerator was found to be significantly higher than that of a single mesh regenerator. Thus a multi mesh regenerator design with a proper combination of regenerator mesh size and length can enhance the regenerator effectiveness.

  20. Dual-controlled release system of drugs for bone regeneration.

    Science.gov (United States)

    Kim, Yang-Hee; Tabata, Yasuhiko

    2015-11-01

    Controlled release systems have been noted to allow drugs to enhance their ability for bone regeneration. To this end, various biomaterials have been used as the release carriers of drugs, such as low-molecular-weight drugs, growth factors, and others. The drugs are released from the release carriers in a controlled fashion to maintain their actions for a long time period. Most research has been focused on the controlled release of single drugs to demonstrate the therapeutic feasibility. Controlled release of two combined drugs, so-called dual release systems, are promising and important for tissue regeneration. This is because the tissue regeneration process of bone formation is generally achieved by multiple bioactive molecules, which are produced from cells by other molecules. If two types of bioactive molecules, (i.e., drugs), are supplied in an appropriate fashion, the regeneration process of living bodies will be efficiently promoted. This review focuses on the bone regeneration induced by dual-controlled release of drugs. In this paper, various dual-controlled release systems of drugs aiming at bone regeneration are overviewed explaining the type of drugs and their release materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Selective extraction of cobalt 60 and radium on CSA's SIMTM system

    International Nuclear Information System (INIS)

    Denton, M.S.; Higgins, I.R.

    1988-01-01

    CSA, has developed and promoted a new ground/well water treatment media and support system for hydrogen sulfide, iron, and manganese called The SIM System. This media was also found to have a selective affinity for arsenic, selenium, antimony, bismuth and lead. All heavy metals have not been checked, but of special rad-waste interest is Co-60 and Ra-226. Barium has been used as a stand-in for Ra in the lab, but both Co and Ba have exhibited very high affinities from Oak Ridge waters. A very attractive feature is that the adsorbed metals may be eluted with a minimum of acid, unlike ion exchangers that regenerate with difficulty or zeolites which dissolve in acids. This opens up the new dimension of extraction/concentration of these contaminants. Ordinary water softening ion exchange resin is excellent for extraction of Ra from drinking water, but, as mentioned, regenerates with great difficulty. The SIM media may be used for pre-treatment with the acid regenerant reloaded on ordinary resin for a very high concentration of Ra, or Co, for final disposal. The very stable SIM media may also be disposed of directly. Strontium (Sr-90) affinity isn't as great as for barium, but is greater than calcium. The separation factor of SIM for Sr/Ca may well be better than the value of two (2) observed for ordinary cation resin. Further studies are being made to demonstrate the full potential of this selective media for certain rad-wastes

  2. The influence of the solid thermal conductivity on active magnetic regenerators

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Engelbrecht, Kurt

    2012-01-01

    The influence of the thermal conductivity of the regenerator solid on the performance of a flat plate active magnetic regenerator (AMR) is investigated using an established numerical AMR model. The cooling power at different (fixed) temperature spans is used as a measure of the performance...... for a range of thermal conductivities, operating frequencies, a long and short regenerator, and finally a regenerator with a low and a high number of transfer units (NTU) regenerator. In this way the performance is mapped out and the impact of the thermal conductivity of the solid is probed. Modeling shows...... that under certain operating conditions, the AMR cycle is sensitive to the solid conductivity. It is found that as the operating frequency is increased it is not only sufficient to have a high NTU regenerator but the regenerator performance will also benefit from increased thermal conductivity in the solid...

  3. Role of metallothioneins in peripheral nerve function and regeneration

    DEFF Research Database (Denmark)

    Ceballos, D; Lago, N; Verdú, E

    2003-01-01

    The physiological role of the metallothionein (MT) family of proteins during peripheral nerve injury and regeneration was examined in Mt1+ 2 and Mt3 knockout (KO) mice. To this end, the right sciatic nerve was crushed, and the regeneration distance was evaluated by the pinch test 2-7 days....... The improved regeneration observed with the Mt3 KO mice was confirmed by compound nerve action potentials that were recorded from digital nerves at 14 dpl only in this group. We conclude that Mt3 normally inhibits peripheral nerve regeneration........ Moreover, the number of regenerating axons in the distal tibial nerve was significantly higher in Mt3KO mice than in the other two strains at 14 dpl. Immunoreactive profiles to protein gene product 9.5 were present in the epidermis and the sweat glands of the plantar skin of the hindpaw of the Mt3 KO group...

  4. Enhanced plant regeneration in lemna minor by amino acids

    International Nuclear Information System (INIS)

    Yang, L.; Han, H.; Zhou, K.; Ren, C.; Zhu, Y.

    2014-01-01

    In present study we investigated the effects of different L-amino acids on the plant regeneration from callus of Lemna minor, and established an efficient protocol. Among the 20 L-amino acids, only L-Ser and L-Gly showed significant improving effect, with the optimal concentration being 1 mM and 1.5 mM, respectively. A regeneration frequency of 46% was observed when the callus transferred to the regeneration medium with addition of 1 mM L-Ser for 11 days. After 26 days of cultivation, the frond regeneration achieved 100% and 94% for 1 mM L-Ser and 1.5 mM L-Gly treatment, respectively. (author)

  5. Nanoparticles for tendon healing and regeneration: literature review.

    Directory of Open Access Journals (Sweden)

    Paolo Domenico Parchi

    2016-08-01

    Full Text Available Tendon injuries are commonly met in the emergency department. Unfortunately, tendon tissue has limited regeneration potential and usually the consequent formation of scar tissue causes inferior mechanical properties Nanoparticles could be used in different way to improve tendon healing and regeneration, ranging from scaffolds manufacturing (increasing the strength and endurance or anti-adhesions, anti-microbial and anti-inflammatory properties to gene therapy. This paper aims to summarize the most relevant studies showing the potential application of nanoparticles for tendon tissue regeneration

  6. Regeneration in an internal combustion engine: Thermal-hydraulic modeling and analysis

    International Nuclear Information System (INIS)

    Thyageswaran, Sridhar

    2016-01-01

    Highlights: • An arrangement is proposed for in-cylinder regeneration in a 4-stroke engine. • Thermodynamic models are formulated for overall cycle analysis. • A design procedure is outlined for micro-channel regenerators. • Partial differential equations are solved for flow inside the regenerator. • Regeneration with lean combustion decreases the idealized cycle efficiency. - Abstract: An arrangement is proposed for a four-stroke internal combustion engine to: (a) recover thermal energy from products of combustion during the exhaust stroke; (b) store that energy as sensible heat in a micro-channel regenerator matrix; and (c) transfer the stored heat to compressed fresh charge that flows through the regenerator during the succeeding mechanical cycle. An extra moveable piston that can be locked at preferred positions and a sequence of valve events enable the regenerator to lose heat to the working fluid during one interval of time but gain heat from the fluid during another interval of time. This paper examines whether or not this scheme for in-cylinder regeneration (ICR) improves the cycle thermal efficiency η I . Models for various thermodynamic processes in the cycle and treatments for unsteady compressible flow and heat transfer inside the regenerator are developed. Digital simulations of the cycle are made. Compared to an idealized engine cycle devoid of regeneration, provisions for ICR seem to deteriorate the thermal efficiency. In an 8:1 compression ratio octane engine simulated with an equivalence ratio of 0.75, η I  = 0.455 with regeneration and η I  = 0.491 without. This study shows that previous claims on efficiency gains via ICR, using highly-simplified models, may be misleading.

  7. Magnetotherapy: The quest for tendon regeneration.

    Science.gov (United States)

    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.

  8. Group C. Initiator paper. Periodontal regeneration--fact or fiction?

    Science.gov (United States)

    Bartold, P M

    2015-01-01

    Numerous techniques have been tried and tested to regenerate tissues lost to periodontal disease. While there has been some success to date, more work is required to move this to a reliable and clinically predictable procedure. Much of the future success for such treatments will rely largely on our understanding of the biology of both developmental and regenerative processes. Nonetheless, despite the noble goal of periodontal regeneration, the relevance of re-creation of a connective tissue attachment has been questioned. Since formation of a long junctional epithelial attachment to the tooth following a variety of periodontal treatment procedures has been shown to be no more susceptible to further breakdown than a non-diseased site, the question arises as to what purpose do we seek the ultimate outcome of periodontal regeneration? The answer lies in the "fact and fiction" of periodontal regeneration. There is no doubt that the regenerative procedures that have been developed can be shown to be biologically successful at the histological level. Furthermore, the results of periodontal regeneration (particularly guided tissue regeneration) have been stable over the long term (at least up to 10 years). However, the techniques currently under use which show the greatest promise (guided tissue regeneration and growth factors) are still clinically unpredictable because of their highly technique-sensitive nature. In addition, whether the slight clinical improvements offered by these procedures over routine open flap debridement procedures are of cost or patient benefit with regards to improved periodontal health and retention of teeth remains to be established. The next phase in regenerative technologies will undoubtedly involve a deeper understanding of the molecular signaling (both intra- and extra-cellular) and cellular differentiation processes involved in the regenerative processes. So in answer to the question of whether periodontal regeneration is fact or fiction

  9. Superhydrophobicity and regeneration of PVDF/SiO2 composite films

    Science.gov (United States)

    Liu, Tao; Li, Xianfeng; Wang, Daohui; Huang, Qinglin; Liu, Zhen; Li, Nana; Xiao, Changfa

    2017-02-01

    Superhydrophobicity of polymers is easily destroyed by careless touching due to the softness of microstructures. In this study, based on a well-constructed polyvinylidene fluoride (PVDF) surface, a novel superhydrophobic PVDF/SiO2 composite film was fabricated by adding hydrophobic SiO2 nanoparticle and solvent into a coagulation bath. The water contact angle of the composite film reached 162.3° and the sliding angle was as low as 1.5°. More importantly, the composite film could be regenerated only through immersing the composite film in the designed regeneration agent. The composition of the designed regeneration agent ensured that SiO2 nanoparticles were firmly adhered on the film surface even under the ultrasonic cleaning. Hence, the superhydrophobicity and self-cleaing property could be regenerated and maintained effectively, and moreover, these propeties could resist a proper pressure. In addition, after many rubbing-regenerating cycles, the regeneration method was still valid.

  10. Myocardial Polyploidization Creates a Barrier to Heart Regeneration in Zebrafish.

    Science.gov (United States)

    González-Rosa, Juan Manuel; Sharpe, Michka; Field, Dorothy; Soonpaa, Mark H; Field, Loren J; Burns, Caroline E; Burns, C Geoffrey

    2018-02-26

    Correlative evidence suggests that polyploidization of heart muscle, which occurs naturally in post-natal mammals, creates a barrier to heart regeneration. Here, we move beyond a correlation by demonstrating that experimental polyploidization of zebrafish cardiomyocytes is sufficient to suppress their proliferative potential during regeneration. Initially, we determined that zebrafish myocardium becomes susceptible to polyploidization upon transient cytokinesis inhibition mediated by dominant-negative Ect2. Using a transgenic strategy, we generated adult animals containing mosaic hearts composed of differentially labeled diploid and polyploid-enriched cardiomyocyte populations. Diploid cardiomyocytes outcompeted their polyploid neighbors in producing regenerated heart muscle. Moreover, hearts composed of equivalent proportions of diploid and polyploid cardiomyocytes failed to regenerate altogether, demonstrating that a critical percentage of diploid cardiomyocytes is required to achieve heart regeneration. Our data identify cardiomyocyte polyploidization as a barrier to heart regeneration and suggest that mobilizing rare diploid cardiomyocytes in the human heart will improve its regenerative capacity. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Natural regeneration processes in big sagebrush (Artemisia tridentata)

    Science.gov (United States)

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2014-01-01

    Big sagebrush, Artemisia tridentata Nuttall (Asteraceae), is the dominant plant species of large portions of semiarid western North America. However, much of historical big sagebrush vegetation has been removed or modified. Thus, regeneration is recognized as an important component for land management. Limited knowledge about key regeneration processes, however, represents an obstacle to identifying successful management practices and to gaining greater insight into the consequences of increasing disturbance frequency and global change. Therefore, our objective is to synthesize knowledge about natural big sagebrush regeneration. We identified and characterized the controls of big sagebrush seed production, germination, and establishment. The largest knowledge gaps and associated research needs include quiescence and dormancy of embryos and seedlings; variation in seed production and germination percentages; wet-thermal time model of germination; responses to frost events (including freezing/thawing of soils), CO2 concentration, and nutrients in combination with water availability; suitability of microsite vs. site conditions; competitive ability as well as seedling growth responses; and differences among subspecies and ecoregions. Potential impacts of climate change on big sagebrush regeneration could include that temperature increases may not have a large direct influence on regeneration due to the broad temperature optimum for regeneration, whereas indirect effects could include selection for populations with less stringent seed dormancy. Drier conditions will have direct negative effects on germination and seedling survival and could also lead to lighter seeds, which lowers germination success further. The short seed dispersal distance of big sagebrush may limit its tracking of suitable climate; whereas, the low competitive ability of big sagebrush seedlings may limit successful competition with species that track climate. An improved understanding of the

  12. Capacity issues in local communities for integral urban regeneration

    Directory of Open Access Journals (Sweden)

    Mrđenović Tatjana

    2013-01-01

    Full Text Available The subject of the research in wider sense is organizational-communication capacity of local communities in Serbia in the frame of sustainable development. Along with this, the paper will explore potentialities of Faludi's model of multiplanning agencies as well as Healey's collaborative theory for better efficiency and effectiveness of planning in the process of urban regeneration. Specifically the paper will research relation between organizational structure of local communities in Serbia and their potentialities to provide adequate communication towards integral information for urban regeneration. Research is framed with a problem of efficiency and effectiveness in creating urban regeneration policies, strategies, designs, and technical solutions. The problem will be focused to Serbian context; characterized with inadequate, transitional, system of governance that is moving from centralistic towards decentralist model. This will be further explored through level and type of participation in the process of urban regeneration. The hypothesis of the research explores the nature of the relation between number and types of communication channels, provided by organizational structure of local communities that should enable effectiveness and efficiency of urban regeneration. In other words the hypothesis is: number and types of communication channels (variable A influences the effectiveness and efficiency of urban planning for sustainable urban regeneration (variable B. The aims of the paper are identification of the regulations between the variables. Expected result is establishing the model for measuring the capacity of local communities for integral urban regeneration.

  13. Post-irradiation thymocyte regeneration after bone marrow transplantation

    International Nuclear Information System (INIS)

    Boersma, W.; Betel, I.; Daculsi, R.; Westen, G. van der

    1981-01-01

    Growth kinetics of the donor-type thymus cell population after transplantation of bone marrow into irradiated syngeneic recipient mice is biphasic. During the first rapid phase of regeneration, lasting until day 19 after transplantation, the rate of development of the donor cells is independent of the number of bone marrow cells inoculated. The second slow phase is observed only when low numbers of bone marrow cells (2.5 x 10 4 ) are transplanted. The decrease in the rate of development is attributed to an efflux of donor cells from the thymus because, at the same time, the first immunologically competent cells are found in spleen. After bone marrow transplantation the regeneration of thymocyte progenitor cells in the marrow is delayed when compared to regeneration of CFUs. Therefore, regenerating marrow has a greatly reduced capacity to restore the thymus cell population. One week after transplantation of 3 x 10 6 cells, 1% of normal capacity of bone marrow is found. It is concluded that the regenerating thymus cells population after bone marrow transplantation is composed of the direct progeny of precursor cells in the inoculum. (author)

  14. SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. Angelici

    2003-06-01

    Refractory 4,6-dimethyldibenzothiophene, which is difficult to remove from petroleum feedstocks, binds to the Ru in Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} by displacing the H{sub 2}O ligand. Thiophene, benzothiophene and dibenzothiophene (DBT) also react with Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} similarly. This binding ability of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} has been used to remove over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily regenerated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks. Solid phase extractants consisting of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, CpRu(CO){sub 2}(BF{sub 4}), CpFe(CO){sub 2}(C{sub 4}H{sub 8}){sup +} and AgX (where X = BF{sub 4}{sup -}, PF{sub 6}{sup -} or NO{sub 3}{sup -}) adsorbed on silica have also been used to remove DBT and 4,6-Me{sub 2}DBT from simulated petroleum feedstocks. The AgX/silica adsorbents remove 90% of the DBT and 4,6-Me{sub 2}DBT and can be regenerated and re-used for multiple extractions, which makes these adsorbents of potential industrial use for the removal of refractory dibenzothiophenes from petroleum feedstocks.

  15. Reconsidering regeneration in metazoans: an evo-devo approach

    Directory of Open Access Journals (Sweden)

    Stefano eTiozzo

    2015-06-01

    Full Text Available Regeneration of body structures is an ability widely but unevenly distributed amongst the animal kingdom. Understanding regenerative biology in metazoans means understanding the multiplicity of the cellular and molecular mechanisms that lead to the differentiation, morphogenesis and ultimately the development of a particular regenerating unit. In this manuscript we critically assess the evolutionary considerations suggesting that regeneration is an ancestral trait rather than a mechanism independently evolved in different taxa. As a general method to test evolutionary hypothesis on regeneration, we propose mechanistically dissecting the regenerative processes according to its conserved chronological steps: wound healing, mobilization of cell precursors and morphogenesis. We then suggest interpreting regenerative biology from an evo-devo perspective, proposing a possible theoretical framework and experimental approaches without necessarily invoking a common origin or only multiple losses of regenerative capabilities.

  16. In vivo study of lens regeneration in Rana cyanophlyctis under ...

    African Journals Online (AJOL)

    SAM

    2014-03-12

    Mar 12, 2014 ... enhanced the percentage lens regeneration not only in young tadpoles but also in froglets. Lens regeneration ability ... Influence of vitamin A and ascorbic acid on lens regeneration in young, mature tadpoles and froglets of the frog Rana cyanophlyctis. Group .... ingested by macrophages. Dorsal iris cells ...

  17. Feathers and fins: non-mammalian models for hair cell regeneration.

    Science.gov (United States)

    Brignull, Heather R; Raible, David W; Stone, Jennifer S

    2009-06-24

    Death of mechanosensory cells in the inner ear results in two profound disabilities: hearing loss and balance disorders. Although mammals lack the capacity to regenerate hair cells, recent studies in mice and other rodents have offered valuable insight into strategies for stimulating hair cell regeneration in mammals. Investigations of model organisms that retain the ability to form new hair cells after embryogenesis, such as fish and birds, are equally important and have provided clues as to the cellular and molecular mechanisms that may block hair cell regeneration in mammals. Here, we summarize studies on hair cell regeneration in the chicken and the zebrafish, discuss specific advantages of each model, and propose future directions for the use of non-mammalian models in understanding hair cell regeneration.

  18. Wilms’ Tumor Blastemal Stem Cells Dedifferentiate to Propagate the Tumor Bulk

    Science.gov (United States)

    Shukrun, Rachel; Pode-Shakked, Naomi; Pleniceanu, Oren; Omer, Dorit; Vax, Einav; Peer, Eyal; Pri-Chen, Sara; Jacob, Jasmine; Hu, Qianghua; Harari-Steinberg, Orit; Huff, Vicki; Dekel, Benjamin

    2014-01-01

    Summary An open question remains in cancer stem cell (CSC) biology whether CSCs are by definition at the top of the differentiation hierarchy of the tumor. Wilms’ tumor (WT), composed of blastema and differentiated renal elements resembling the nephrogenic zone of the developing kidney, is a valuable model for studying this question because early kidney differentiation is well characterized. WT neural cell adhesion molecule 1-positive (NCAM1+) aldehyde dehydrogenase 1-positive (ALDH1+) CSCs have been recently isolated and shown to harbor early renal progenitor traits. Herein, by generating pure blastema WT xenografts, composed solely of cells expressing the renal developmental markers SIX2 and NCAM1, we surprisingly show that sorted ALDH1+ WT CSCs do not correspond to earliest renal stem cells. Rather, gene expression and proteomic comparative analyses disclose a cell type skewed more toward epithelial differentiation than the bulk of the blastema. Thus, WT CSCs are likely to dedifferentiate to propagate WT blastema. PMID:25068119

  19. Structure and catalytic activity of regenerated spent hydrotreating catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.S.; Massoth, F.E.; Furimsky, E. (Utah University, Salt Lake City, UT (USA). Dept. of Fuels Engineering)

    1992-11-01

    Two spent catalysts, obtained from different hydrodemetallation operations, were regenerated by two different treatments, viz. 2% (V/V) O[sub 2]/N[sub 2] and air. One spent catalyst (B), contained 3 wt% V and 15 wt% C, while the other (H) contained 10 wt% V, 14 wt% C and 8 wt% Fe. After regeneration in the O[sub 2]/N[sub 2] stream, catalyst B showed essentially complete recovery of its original surface area, whereas catalyst H showed only 70% recovery. Both catalysts showed substantial losses in surface area by the air treatment. Catalytic activity tests on the regenerated catalysts for hydrodesulfurization of thiophene and for hydrogenation of 1-hexene showed low recovery of activities, even for the regenerated catalyst in which the surface area had been completely recovered. X-ray diffraction analyses of the spent-regenerated catalysts revealed substantial changes in catalyst structure. Surface area and catalytic activity results were qualitatively explained by these catalyst structural changes. 17 refs., 1 fig., 3 tabs.

  20. Extraction of tocopherolquinone from commercially produced vegetable oil waste and its regeneration back to vitamin E

    Science.gov (United States)

    Bayala, Isso

    Vegetable oils are the most important natural source of vitamin E in the human diet. These oils are refined in order to eliminate impurities and undesirable substances that may affect the taste or cause health risks. While the goal of the refinery is to improve the quality of certain organoleptic parameters such as odors, it also has some negative impacts on the content and stability of the micronutrients such as tocopherols and tocotrienols. Synthetic vitamin E now manufactured as all-racemic alpha tocopheryl acetate is usually marked as d, l-tocopherol or d, l-tocopheryl acetate with no known side effects, but has been proven to be less active than its natural form. Naturopathic and orthomolecular medicine advocates consider the synthetic vitamin E forms to offer little or no benefit for cancer, circulatory and heart diseases. The market for vitamin E has been growing since the year 2000 causing a gradual rise in pricing because of the shortage in supplies. On a geographical basis North America constitutes the largest consumer on the planet with 50 % of the synthetic vitamin E world market followed by Europe with 25 % and Latin America and Asia Pacific sharing equally the remaining balance. In response to the shortfall, several companies are modifying their operations by rationalizing their older facilities while upgrading technology and adding capacity to meet the demand. But this response has also its downside with companies obligated to meet tough environmental regulations. The purpose of the present dissertation was to develop a method that can help industries involved in vitamin E production maximize their productivity by transforming some of the waste products to vitamin E. To that end, a cost effective simple method was developed in chapter II using tin (II) to regenerate tocopherolquinone back to vitamin E. Chapter II also concerns a method developed to reduce tocopherolquinone back to vitamin E but this time using the chemical species chromium (III

  1. Multiple changes in peptide and lipid expression associated with regeneration in the nervous system of the medicinal leech.

    Directory of Open Access Journals (Sweden)

    Céline Meriaux

    2011-04-01

    Full Text Available The adult medicinal leech central nervous system (CNS is capable of regenerating specific synaptic circuitry after a mechanical lesion, displaying evidence of anatomical repair within a few days and functional recovery within a few weeks. In the present work, spatiotemporal changes in molecular distributions during this phenomenon are explored. Moreover, the hypothesis that neural regeneration involves some molecular factors initially employed during embryonic neural development is tested.Imaging mass spectrometry coupled to peptidomic and lipidomic methodologies allowed the selection of molecules whose spatiotemporal pattern of expression was of potential interest. The identification of peptides was aided by comparing MS/MS spectra obtained for the peptidome extracted from embryonic and adult tissues to leech transcriptome and genome databases. Through the parallel use of a classical lipidomic approach and secondary ion mass spectrometry, specific lipids, including cannabinoids, gangliosides and several other types, were detected in adult ganglia following mechanical damage to connected nerves. These observations motivated a search for possible effects of cannabinoids on neurite outgrowth. Exposing nervous tissues to Transient Receptor Potential Vanilloid (TRPV receptor agonists resulted in enhanced neurite outgrowth from a cut nerve, while exposure to antagonists blocked such outgrowth.The experiments on the regenerating adult leech CNS reported here provide direct evidence of increased titers of proteins that are thought to play important roles in early stages of neural development. Our data further suggest that endocannabinoids also play key roles in CNS regeneration, mediated through the activation of leech TRPVs, as a thorough search of leech genome databases failed to reveal any leech orthologs of the mammalian cannabinoid receptors but revealed putative TRPVs. In sum, our observations identify a number of lipids and proteins that may

  2. Regenerate augmentation with bone marrow concentrate after traumatic bone loss

    Directory of Open Access Journals (Sweden)

    Jan Gessmann

    2012-03-01

    Full Text Available Distraction osteogenesis after post-traumatic segmental bone loss of the tibia is a complex and time-consuming procedure that is often complicated due to prolonged consolidation or complete insufficiency of the regenerate. The aim of this feasibility study was to investigate the potential of bone marrow aspiration concentrate (BMAC for percutaneous regenerate augmentation to accelerate bony consolidation of the regenerate. Eight patients (age 22-64 with an average posttraumatic bone defect of 82.4 mm and concomitant risk factors (nicotine abuse, soft-tissue defects, obesity and/or circulatory disorders were treated with a modified Ilizarov external frame using an intramedullary cable transportation system. At the end of the distraction phase, each patient was treated with a percutaneously injection of autologous BMAC into the centre of the regenerate. The concentration factor was analysed using flow cytometry. The mean follow up after frame removal was 10 (4-15 months. With a mean healing index (HI of 36.9 d/cm, bony consolidation of the regenerate was achieved in all eight cases. The mean concentration factor of the bone marrow aspirate was 4.6 (SD 1.23. No further operations concerning the regenerate were needed and no adverse effects were observed with the BMAC procedure. This procedure can be used for augmentation of the regenerate in cases of segmental bone transport. Further studies with a larger number of patients and control groups are needed to evaluate a possible higher success rate and accelerating effects on regenerate healing.

  3. Regeneration of Full Scale Adsorptive Media Systems - Update

    Science.gov (United States)

    Presentation provides an update of the regeneration studies conducted at Twentynine Palms, CA. Following a short introduction, the presentation summarizes the results of the three regeneration tests conducted on the exhausted media of the arsenic removal system at Twentynine Pal...

  4. In vitro regeneration of selected commercial Tanzanian open ...

    African Journals Online (AJOL)

    Using this regeneration system Situka M-1, Staha and TMV-1 can now be improved against various production constraints through genetic engineering. Key words: 2, 4-dichlorophexyacetic acid, embryogenic callus, immature zygotic embryos, regeneration frequency, somatic embryos, Tanzanian open pollinated maize.

  5. Oak regeneration potential increased by shelterwood treatments

    Science.gov (United States)

    Richard C. Schlesinger; Ivan L. Sander; Kenneth R. Davidson

    1993-01-01

    In much of the Central Hardwood Forest Region, oak species are not regenerating well, even though large oak trees are common within the existing forests. The shelterwood method has been suggested as a potential tool for establishing and developing advanced regeneration where it is lacking. The 10-yr results from a study of several variants of the shelterwood method...

  6. A novel energy regeneration system for emulsion pump tests

    Energy Technology Data Exchange (ETDEWEB)

    Yilei, Li; Zhencai, Zhu; Guohua, Cao [China University of Mining and Technology, Xuzhou (China); Guoan, Chen [Command Academy of the Corps of Engineers, Xuzhou (China)

    2013-04-15

    A novel energy regeneration system based on cylinders and a rectifier valve for emulsion pump tests is presented and studied. The overall structure and working principles of this system are introduced. Both simulation and experiments are carried out to investigate the energy regeneration feasibility and capability of this novel system. The simulation and experimental results validate that this system is able to save energy and satisfy the test requirement. The energy recovery coefficient and overall energy regeneration coefficient of the test bench are 0.785 and 0.214, respectively. Measures to improve these two coefficients are also given accordingly after analysis of power loss. This novel system brings a new method of energy regeneration for emulsion pump tests.

  7. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    Science.gov (United States)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

  8. Optogenetically enhanced axon regeneration: motor versus sensory neuron-specific stimulation.

    Science.gov (United States)

    Ward, Patricia J; Clanton, Scott L; English, Arthur W

    2018-02-01

    Brief neuronal activation in injured peripheral nerves is both necessary and sufficient to enhance motor axon regeneration, and this effect is specific to the activated motoneurons. It is less clear whether sensory neurons respond in a similar manner to neuronal activation following peripheral axotomy. Further, it is unknown to what extent enhancement of axon regeneration with increased neuronal activity relies on a reflexive interaction within the spinal circuitry. We used mouse genetics and optical tools to evaluate the precision and selectivity of system-specific neuronal activation to enhance axon regeneration in a mixed nerve. We evaluated sensory and motor axon regeneration in two different mouse models expressing the light-sensitive cation channel, channelrhodopsin (ChR2). We selectively activated either sensory or motor axons using light stimulation combined with transection and repair of the sciatic nerve. Regardless of genotype, the number of ChR2-positive neurons whose axons had regenerated successfully was greater following system-specific optical treatment, with no effect on the number of ChR2-negative neurons (whether motor or sensory neurons). We conclude that acute system-specific neuronal activation is sufficient to enhance both motor and sensory axon regeneration. This regeneration-enhancing effect is likely cell autonomous. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  9. Emdogain--periodontal regeneration based on biomimicry.

    Science.gov (United States)

    Gestrelius, S; Lyngstadaas, S P; Hammarström, L

    2000-06-01

    Biomimicry has been introduced as a term for innovations inspired by nature [1]. Such innovations may appear in almost every part of modern society. This review on the effects of enamel matrix proteins on the formation of cementum and the development of emdogain for regeneration of periodontal tissues lost due to periodontitis shows an example of biomimicry in dentistry. Findings from clinical and laboratory investigations are summarized and the biological basis for enamel matrix-induced periodontal regeneration is discussed.

  10. Regeneration and health: a structured, rapid literature review.

    Science.gov (United States)

    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

  11. Histomorphometric evaluation of a calcium-phosphosilicate putty bone substitute in extraction sockets.

    Science.gov (United States)

    Kotsakis, Georgios A; Joachim, Frederic P C; Saroff, Stephen A; Mahesh, Lanka; Prasad, Hari; Rohrer, Michael D

    2014-01-01

    The objective of this study was to evaluate bone regeneration in 24 sockets grafted with a calcium phosphosilicate putty alloplastic bone substitute. A core was obtained from 17 sockets prior to implant placement for histomorphometry at 5 to 6 months postextraction. Radiographic analysis during the same postextraction healing period showed radiopaque tissue in all sockets. Histomorphometric analysis revealed a mean vital bone content of 31.76% (± 14.20%) and residual graft content of 11.47% (± 8.99%) after a mean healing period of 5.7 months. The high percentage of vital bone in the healed sites in combination with its timely absorption rate suggest that calcium phosphosilicate putty can be a reliable choice for osseous regeneration in extraction sockets.

  12. Mathematical simulation and calculation of continuous countercurrent process of ion-exchange extraction of strontium from strongly mineralized solutions

    International Nuclear Information System (INIS)

    Nikashina, V.A.; Venitsianov, E.V.; Ivanov, V.A.; Gur'yanova, L.N.; Nikolaev, N.P.; Baturova, L.L.; Moskovskij Gosudarstvennyj Univ., Moscow

    1993-01-01

    A program 'Countercurrent' is developed for the simulation of a continuous ion-exchange extraction of strontium from the strongly mineralized solutions containing NaCl and CaCl 2 using carboxylic cation exchanger KB-4 in countercurrent columns. The use of the program allows one to calculate the consitions of Ca and Sr separation depending on the modes of operation at the stage of sorption as well as regeneration, to calculate a residual Sr content on an overloaded sorbent and Sr separation on an incompletely regenerated KB-4, and to find the optimal separation conditions

  13. Generating private co-investments in area-based urban regeneration: Lessons from Denmark

    DEFF Research Database (Denmark)

    Jensen, Jesper Ole; Larsen, Jacob Norvig; Storgaard, Kresten

    a factor 5 times higher than the public investments in the areas, in terms of urban regeneration subsidies. Private investments, however, might cover different property investment strategies: ‘Passive management’, ‘active management’ and ‘development’. We suggest that for the urban regeneration areas......In recent years, public-private collaboration as well as private co-investments has been intensely promoted in Danish area-based urban regeneration policy and programmes. The paper will discuss to which extent these ambitions have been full-filled, and what has actually attracted private...... investments to the urban regeneration areas. The paper is based on evaluations of the Danish area-based regeneration programmes, as well as research on private investments in selected urban regeneration areas. Our research shows that area-based urban regeneration in average generates private investments...

  14. Plant Regeneration Through Tissue Culture Of Pear Millet ...

    African Journals Online (AJOL)

    1. 1. 2,5), MS(5) and N6(1.100.25) culture media, calli embryogenic potential and fertile plants regeneration were conserved for more than 12 months. Characteristics of regenerated plants were similar to control. It appears that dissected shoot ...

  15. Regeneration of baroafferents after implantation into different vessels

    NARCIS (Netherlands)

    Stevens, Markus F.; Hermanns, Henning; Freynhagen, Rainer; Novotny, Gerd E. K.; Lipfert, Peter

    2007-01-01

    Regeneration of peripheral nerves involves an essential contribution by surrounding tissues. This study focuses on the role of the target tissue on the regeneration of afferent peripheral nerves. We hypothesized that nerves implanted into the appropriate target tissue regain their function, whereas

  16. Analysis of conifer forest regeneration using Landsat Thematic Mapper data

    Science.gov (United States)

    Fiorella, Maria; Ripple, William J.

    1995-01-01

    Landsat Thematic Mapper (TM) data were used to evaluate young conifer stands in the western Cascade Mountains of Oregon. Regression and correlation analyses were used to describe the relationships between TM band values and age of young Douglas-fir stands (2 to 35 years old). Spectral data from well regenerated Douglas-fir stands were compared to those of poorly regenerated conifer stands. TM bands 1, 2, 3, 5, 6, and 7 were inversely correlated with the age (r greater than or equal to -0.80) of well regenerated Douglas-fir stands. Overall, the 'structural index' (TM 4/5 ratio) had the highest correlation to age of Douglas-fir stands (r = 0.96). Poorly regenerated stands were spectrally distinct from well regenerated Douglas-fir stands after the stands reached an age of approximately 15 years.

  17. The influence of pressure ratio on the regenerator performance

    Science.gov (United States)

    Lin, Y.; Zhu, S.

    2017-12-01

    For a multi-stage pulse tube refrigerator with displacer, improving the regenerator efficiency is important. A displacer can get higher operating pressure ratio compared with inertance tube. The pressure ratio and porosity influence on the regenerator performance with is discussed, and CFD simulation is done on a two-stage pulse tube refrigerator with displacer to show that mass flow rate and pressure wave relation in the regenerator can be realized by a step-displacer.

  18. Social Housing in Urban Regeneration. Regeneration Heritage Existing Building: Methods and Strategies

    Directory of Open Access Journals (Sweden)

    Maria Antonia Giannino

    2014-05-01

    Full Text Available The theme of urban regeneration has played a strategic role during the last two decades in European and national urban building policies. Current addresses, also defined in Leipzig Charter on Sustainable European Cities in 2007, indentify the necessity to invest in requalification of degraded residential assets and not in new developments, individuating in urban regeneration the main tool for development of contemporary city. Public neighborhoods have developed, historically, a wide set of common problems. They are not only due to wrong planning but also to the concept of “housing for masses”.  The original ambition of modern settlment, developed from GermanSiedlung, was to be an autonomous part, on the point of view of morphology, in urban expansion. Joined by new developments, a lot of neighborhoods became benchmarks for suburban areas and now we can define themas “new urban centralities”. So theirrole in urbandynamics has changed and they can be individuate dasprecious reserves of public spaces and potential incubators for regeneration of larger areas. Analyzing some Italian and European case studies, themostinnovative relate to the densification of open spaces, inserting new services in a general redesign of green areas; concentration of built surfaces, in order to reduce land consumption and introduction of different residential types in order to improve mischbebauung. The reasons for an active recovery are motivated by the criteria of environmental sustainability and saving land, have relaunched compact projects with medium to highdensity.

  19. Multimodal-3D imaging based on μMRI and μCT techniques bridges the gap with histology in visualization of the bone regeneration process.

    Science.gov (United States)

    Sinibaldi, R; Conti, A; Sinjari, B; Spadone, S; Pecci, R; Palombo, M; Komlev, V S; Ortore, M G; Tromba, G; Capuani, S; Guidotti, R; De Luca, F; Caputi, S; Traini, T; Della Penna, S

    2018-03-01

    Bone repair/regeneration is usually investigated through X-ray computed microtomography (μCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (μMRI) shows a richer tissue contrast than μCT, despite at lower resolution, and could be combined with μCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine μMRI and μCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between μCT and μMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, μMRI and μCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Reversing a tree regeneration crisis in an endangered ecoregion.

    Science.gov (United States)

    Fischer, Joern; Stott, Jenny; Zerger, Andre; Warren, Garth; Sherren, Kate; Forrester, Robert I

    2009-06-23

    Global food demand is growing rapidly. Livestock grazing can provide a valuable source of protein, but conventional grazing is often unsustainable. We studied an 800,000-ha section of a threatened ecoregion in southeastern Australia. Conventional management in the region involves continuous livestock grazing with few rest periods and regular fertilizer application. By using remotely sensed data on tree cover and extensive field data on livestock grazing regimes, soil chemistry, tree diameters, and tree regeneration, we show that the region is facing a tree regeneration crisis. Under conventional management, across the region, millions of hectares of land currently supporting tens of millions of trees will be treeless within decades from now. This would have severe negative ramifications for biodiversity and key ecosystem services, including water infiltration and shade provision for livestock. However, we identified an unexpected win-win solution for tree regeneration and commercial grazing. A relatively new practice in the region is fast-rotational grazing, characterized by prolonged rest periods in between short, intensive grazing events. The probability of regeneration under fast-rotational grazing was up to 4-fold higher than under conventional grazing, and it did not differ significantly from the probability of regeneration in ungrazed areas. In addition, trees were more likely to regenerate where soil nutrient levels were low. These findings suggest that the tree regeneration crisis can be reversed by applying low-input, fast-rotational grazing. New policy settings supporting these practices could signal a turning point for the region, from ecological decline to ecological recovery.

  1. Re-use of radio-thermoluminescent LiF without regeneration; Reemploi sans regeneration du LiF radiothermoluminescent

    Energy Technology Data Exchange (ETDEWEB)

    Portal, G; Francois, H; Blanchard, Ph [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    There is at the present time a rapid development of dosimetry techniques using thermoluminescence. Amongst the many substance actually in use, research laboratories generally employ lithium fluoride which is of particular interest for dosing {beta} radiation and low-energy X and {gamma} radiation. It might also be of use in radioprotection if its practical application were simpler. It has in effect unstable traps situated just below the surface which adversely affect the measurements if the material is not regenerated before each operation; this process considerably complicates the carrying out of measurements in the field of radioprotection. We have prepared a lithium fluoride giving unstable peaks which are less pronounced that those of the commercially available product and which can therefore be used without regeneration. In this report we compare the thermoluminescence curves for these two products. An analysis is given of the reasons for which this radio-thermoluminescent product has a stable luminescence curve and can be used almost one hundred times without being regenerated. We show that this quality can be retained when the LiF is used as a filler for teflon for applications in detectors. (authors) [French] On assiste a un developpement rapide des techniques de dosimetrie par thermoluminescence. Parmi les nombreux materiaux actuellement utilises, les laboratoires de recherche font generalement porter leur preference sur le fluorure de lithium qui est particulierement interessant pour la dosimetrie des rayonnements {beta} et des rayonnements X et {gamma} de faible energie. Ses qualites seraient egalement appreciees en radioprotection si sa mise en oeuvre etait plus simple. Il presente en effet des pieges instables situes a une faible profondeur qui alterent les mesures si l'on ne procede pas, avant chaque utilisation, a la regeneration du materiau, operation qui alourdit considerablement les mesures pratiquees en radioprotection. Nous avons prepare un

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

    Science.gov (United States)

    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.

  3. All-Optical Regeneration System for Optical Wavelength Division Multiplexed Communication Systems

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to an all-optical regeneration system for regeneration of optical wavelength division multiplexed WDM data signals in an optical WDM communication system. The system comprises a WDM-to-Optical time domain multiplexing OTDM, WDM-to-OTDM, converter, capable of converting....... The system additionally comprises an OTDM-to-WDM converter for converting the output OTDM data signal to an output WDM data signal. An input of the all-optical regenerator unit is in optical communication with an output of the WDM-to-OTDM converter, and an output of the all-optical regenerator unit...... an input WDM data signal comprising multiple wavelength channels into an input OTDM data signal comprising multiple time multiplexed time channels. The system further comprises an all-optical regenerator unit being configured for regenerating the input OTDM data signal into an output OTDM data signal...

  4. Evaluation of somatic embryogenesis and plant regeneration in ...

    African Journals Online (AJOL)

    In an attempt to develop a successfully reproducible in vitro regeneration protocol for a group of diverse sorghum genotypes, 10 sorghum lines including locally adapted and commercially important elite genotypes were assessed for their regeneration potential on different culture media–containing adequate growth ...

  5. Regeneration of Optic Nerve

    Directory of Open Access Journals (Sweden)

    Kwok-Fai So

    2011-05-01

    Full Text Available The optic nerve is part of the central nervous system (CNS and has a structure similar to other CNS tracts. The axons that form the optic nerve originate in the ganglion cell layer of the retina and extend through the optic tract. As a tissue, the optic nerve has the same organization as the white matter of the brain in regard to its glia. There are three types of glial cells: Oligodendrocytes, astrocytes, and microglia. Little structural and functional regeneration of the CNS takes place spontaneously following injury in adult mammals. In contrast, the ability of the mammalian peripheral nervous system (PNS to regenerate axons after injury is well documented. A number of factors are involved in the lack of CNS regeneration, including: (i the response of neuronal cell bodies against the damage; (ii myelin-mediated inhibition by oligodendrocytes; (iii glial scarring, by astrocytes; (iv macrophage infiltration; and (v insufficient trophic factor support. The fundamental difference in the regenerative capacity between CNS and PNS neuronal cell bodies has been the subject of intensive research. In the CNS the target normally conveys a retrograde trophic signal to the cell body. CNS neurons die because of trophic deprivation. Damage to the optic nerve disconnects the neuronal cell body from its target-derived trophic peptides, leading to the death of retinal ganglion cells. Furthermore, the axontomized neurons become less responsive to the peptide trophic signals they do receive. On the other hand, adult PNS neurons are intrinsically responsive to neurotrophic factors and do not lose trophic responsiveness after axotomy. In this talk different strategies to promote optic-nerve regeneration in adult mammals are reviewed. Much work is still needed to resolve many issues. This is a very important area of neuroregeneration and neuroprotection, as currently there is no cure after traumatic optic nerve injury or retinal disease such as glaucoma, which

  6. Regenerating mixed oak stands in Pennsylvania: a quarter-century retrospective

    Science.gov (United States)

    P. J. Gould; K. C. Steiner; J. C. Finley; M. E. McDill

    2003-01-01

    The outcomes of regeneration treatments in 90 oak-dominated stands in Pennsylvania are examined 20 to 33 years after treatment. Approximately one-quarter of the stands failed to reach 50 percent stocking after at least 20 years, but most stands regenerated successfully. Red maple is the most frequently observed species in the regenerated stands, followed by oak species...

  7. Helping the Retina Regenerate

    Science.gov (United States)

    ... the retina News Brief 03/30/17 A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored ...

  8. Biological regeneration of humic acid-loaded partially exhausted activated carbon (down flow system)

    International Nuclear Information System (INIS)

    Durrani, M.A.Q.J.; Martin, R.J.; Khaliq, F.

    1995-01-01

    This paper represents the report on the biological regeneration of partially exhausted (down flow) activated carbon following the experimental studies carried out at the university of Birmingham, UK. The Research investigated the extent of bio regeneration of humic acid of concentration 100 mg/l. Bio regeneration in the partial exhaustion system (down flow) was evaluated in terms of substrate removal. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents. The regeneration performance of the bio regeneration, partially exhausted (with humic acid) carbon increased during initial cycles, later on, it deteriorated significantly with each successive regeneration cycle. Microbial fouling of the carbon, especially at the bottom of the carbon bed was found to produce a substantial deterioration of the bio regeneration performance. (author)

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

    NARCIS (Netherlands)

    Geuijen, K.P.M.; Schasfoort, R.B.; Wijffels, R.H.; Eppink, M.H.M.

    2014-01-01

    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

  10. Biomaterials for cardiac regeneration

    CERN Document Server

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  11. Localization of QTLs for in vitro plant regeneration in tomato.

    Science.gov (United States)

    Trujillo-Moya, Carlos; Gisbert, Carmina; Vilanova, Santiago; Nuez, Fernando

    2011-10-20

    Low regeneration ability limits biotechnological breeding approaches. The influence of genotype in the regeneration response is high in both tomato and other important crops. Despite the various studies that have been carried out on regeneration genetics, little is known about the key genes involved in this process. The aim of this study was to localize the genetic factors affecting regeneration in tomato. We developed two mapping populations (F2 and BC1) derived from a previously selected tomato cultivar (cv. Anl27) with low regeneration ability and a high regeneration accession of the wild species Solanum pennellii (PE-47). The phenotypic assay indicated dominance for bud induction and additive effects for both the percentage of explants with shoots and the number of regenerated shoots per explant. Two linkage maps were developed and six QTLs were identified on five chromosomes (1, 3, 4, 7 and 8) in the BC1 population by means of the Interval Mapping and restricted Multiple QTL Mapping methods. These QTLs came from S. pennellii, with the exception of the minor QTL located on chromosome 8, which was provided by cv. Anl27. The main QTLs correspond to those detected on chromosomes 1 and 7. In the F2 population, a QTL on chromosome 7 was identified on a similar region as that detected in the BC1 population. Marker segregation distortion was observed in this population in those areas where the QTLs of BC1 were detected. Furthermore, we located two tomato candidate genes using a marker linked to the high regeneration gene: Rg-2 (a putative allele of Rg-1) and LESK1, which encodes a serine/threonine kinase and was proposed as a marker for regeneration competence. As a result, we located a putative allele of Rg-2 in the QTL detected on chromosome 3 that we named Rg-3. LESK1, which is also situated on chromosome 3, is outside Rg-3. In a preliminary exploration of the detected QTL peaks, we found several genes that may be related to regeneration. In this study we have

  12. Localization of QTLs for in vitro plant regeneration in tomato

    Directory of Open Access Journals (Sweden)

    Nuez Fernando

    2011-10-01

    Full Text Available Abstract Background Low regeneration ability limits biotechnological breeding approaches. The influence of genotype in the regeneration response is high in both tomato and other important crops. Despite the various studies that have been carried out on regeneration genetics, little is known about the key genes involved in this process. The aim of this study was to localize the genetic factors affecting regeneration in tomato. Results We developed two mapping populations (F2 and BC1 derived from a previously selected tomato cultivar (cv. Anl27 with low regeneration ability and a high regeneration accession of the wild species Solanum pennellii (PE-47. The phenotypic assay indicated dominance for bud induction and additive effects for both the percentage of explants with shoots and the number of regenerated shoots per explant. Two linkage maps were developed and six QTLs were identified on five chromosomes (1, 3, 4, 7 and 8 in the BC1 population by means of the Interval Mapping and restricted Multiple QTL Mapping methods. These QTLs came from S. pennellii, with the exception of the minor QTL located on chromosome 8, which was provided by cv. Anl27. The main QTLs correspond to those detected on chromosomes 1 and 7. In the F2 population, a QTL on chromosome 7 was identified on a similar region as that detected in the BC1 population. Marker segregation distortion was observed in this population in those areas where the QTLs of BC1 were detected. Furthermore, we located two tomato candidate genes using a marker linked to the high regeneration gene: Rg-2 (a putative allele of Rg-1 and LESK1, which encodes a serine/threonine kinase and was proposed as a marker for regeneration competence. As a result, we located a putative allele of Rg-2 in the QTL detected on chromosome 3 that we named Rg-3. LESK1, which is also situated on chromosome 3, is outside Rg-3. In a preliminary exploration of the detected QTL peaks, we found several genes that may be related

  13. Transforming growth factor: beta signaling is essential for limb regeneration in axolotls.

    Directory of Open Access Journals (Sweden)

    Mathieu Lévesque

    2007-11-01

    Full Text Available Axolotls (urodele amphibians have the unique ability, among vertebrates, to perfectly regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. The axolotl limb is the most widely used structure as an experimental model to study tissue regeneration. The process is well characterized, requiring multiple cellular and molecular mechanisms. The preparation phase represents the first part of the regeneration process which includes wound healing, cellular migration, dedifferentiation and proliferation. The redevelopment phase represents the second part when dedifferentiated cells stop proliferating and redifferentiate to give rise to all missing structures. In the axolotl, when a limb is amputated, the missing or wounded part is regenerated perfectly without scar formation between the stump and the regenerated structure. Multiple authors have recently highlighted the similarities between the early phases of mammalian wound healing and urodele limb regeneration. In mammals, one very important family of growth factors implicated in the control of almost all aspects of wound healing is the transforming growth factor-beta family (TGF-beta. In the present study, the full length sequence of the axolotl TGF-beta1 cDNA was isolated. The spatio-temporal expression pattern of TGF-beta1 in regenerating limbs shows that this gene is up-regulated during the preparation phase of regeneration. Our results also demonstrate the presence of multiple components of the TGF-beta signaling machinery in axolotl cells. By using a specific pharmacological inhibitor of TGF-beta type I receptor, SB-431542, we show that TGF-beta signaling is required for axolotl limb regeneration. Treatment of regenerating limbs with SB-431542 reveals that cellular proliferation during limb regeneration as well as the expression of genes directly dependent on TGF-beta signaling are down-regulated. These data directly implicate TGF

  14. MHD (Magnetohydrodynamics) recovery and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    McIlroy, R. A. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Probert, P. B. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Lahoda, E. J. [Westinghouse Electric Corp., Pittsburgh, PA (United States); Swift, W. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Jackson, D. M. [Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States); Prasad, J. [Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States); Martin, J. [Hudson Engineering (United States); Rogers, C. [Hudson Engineering (United States); Ho, K. K. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Senary, M. K. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Lee, S. [Univ. of Akron, OH (United States)

    1988-10-01

    A two-phase program investigating MHD seed regeneration is described. In Phase I, bench scale experiments were carried out to demonstrate the technical feasibility of a proposed Seed Regeneration Process. The Phase I data has been used for the preliminary design of a Proof-of-Concept (POC) plant which will be built and tested in Phase II. The Phase I data will also be used to estimate the costs of a 300 Mw(t) demonstration plant for comparison with other processes. The Seed Regeneration Process consists of two major subprocesses; a Westinghouse Dry Reduction process and a modified Tampella (sulfur) Recovery process. The Westinghouse process reduces the recovered spent seed (i.e., potassium sulfate) to potassium polysulfide in a rotary kiln. The reduction product is dissolved in water to form green liquor, clarified to remove residual coal ash, and sent to the Tampella sulfur release system. The sulfur is released using carbon dioxide from flue gas in a two stage reaction. The sulfur is converted to elemental sulfur as a marketable by product. The potassium is crystallized from the green liquor and dried to the anhydrous form for return to the MHD unit.

  15. Regeneration of Algerian germplasm by stigma/style somatic ...

    African Journals Online (AJOL)

    ... days in most of the cultured genotypes. Formed embryos were cultured in a single tube before in vivo acclimatization. After sanitary assays, regenerated plants were shown to be free from the agents detected in the mother trees. Key words: Algeria, citrus germplasm, plant regeneration, sanitation, somatic embryogenesis.

  16. Extraction and representation of common feature from uncertain facial expressions with cloud model.

    Science.gov (United States)

    Wang, Shuliang; Chi, Hehua; Yuan, Hanning; Geng, Jing

    2017-12-01

    Human facial expressions are key ingredient to convert an individual's innate emotion in communication. However, the variation of facial expressions affects the reliable identification of human emotions. In this paper, we present a cloud model to extract facial features for representing human emotion. First, the uncertainties in facial expression are analyzed in the context of cloud model. The feature extraction and representation algorithm is established under cloud generators. With forward cloud generator, facial expression images can be re-generated as many as we like for visually representing the extracted three features, and each feature shows different roles. The effectiveness of the computing model is tested on Japanese Female Facial Expression database. Three common features are extracted from seven facial expression images. Finally, the paper is concluded and remarked.

  17. Potential Use of Stem Cells for Kidney Regeneration

    Directory of Open Access Journals (Sweden)

    Takashi Yokoo

    2011-01-01

    Full Text Available Significant advances have been made in stem cell research over the past decade. A number of nonhematopoietic sources of stem cells (or progenitor cells have been identified, including endothelial stem cells and neural stem cells. These discoveries have been a major step toward the use of stem cells for potential clinical applications of organ regeneration. Accordingly, kidney regeneration is currently gaining considerable attention to replace kidney dialysis as the ultimate therapeutic strategy for renal failure. However, due to anatomic complications, the kidney is believed to be the hardest organ to regenerate; it is virtually impossible to imagine such a complicated organ being completely rebuilt from pluripotent stem cells by gene or chemical manipulation. Nevertheless, several groups are taking on this big challenge. In this manuscript, current advances in renal stem cell research are reviewed and their usefulness for kidney regeneration discussed. We also reviewed the current knowledge of the emerging field of renal stem cell biology.

  18. Releasing 'brakes' to nerve regeneration: intrinsic molecular targets.

    Science.gov (United States)

    Krishnan, Anand; Duraikannu, Arul; Zochodne, Douglas W

    2016-02-01

    Restoring critical neuronal architecture after peripheral nerve injury is challenging. Although immediate regenerative responses to peripheral axon injury involve the synthesis of regeneration-associated proteins in neurons and Schwann cells, an unfavorable balance between growth facilitatory and growth inhibitory signaling impairs the growth continuum of injured peripheral nerves. Molecules involved with the signaling network of tumor suppressors play crucial roles in shifting the balance between growth and restraint during axon regeneration. An understanding of the molecular framework of tumor suppressor molecules in injured neurons and its impact on stage-specific regeneration events may expose therapeutic intervention points. In this review we discuss how signaling networks of the specific tumor suppressors PTEN, Rb1, p53, p27 and p21 are altered in injured peripheral nerves and how this impacts peripheral nerve regeneration. Insights into the roles and importance of these pathways may open new avenues for improving the neurological deficits associated with nerve injury. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  19. Modifying Lipid Rafts Promotes Regeneration and Functional Recovery

    Directory of Open Access Journals (Sweden)

    Nardos G. Tassew

    2014-08-01

    Full Text Available Ideal strategies to ameliorate CNS damage should promote both neuronal survival and axon regeneration. The receptor Neogenin promotes neuronal apoptosis. Its ligand prevents death, but the resulting repulsive guidance molecule a (RGMa-Neogenin interaction also inhibits axonal growth, countering any prosurvival benefits. Here, we explore strategies to inhibit Neogenin, thus simultaneously enhancing survival and regeneration. We show that bone morphogenetic protein (BMP and RGMa-dependent recruitment of Neogenin into lipid rafts requires an interaction between RGMa and Neogenin subdomains. RGMa or Neogenin peptides that prevent this interaction, BMP inhibition by Noggin, or reduction of membrane cholesterol all block Neogenin raft localization, promote axon outgrowth, and prevent neuronal apoptosis. Blocking Neogenin raft association influences axonal pathfinding, enhances survival in the developing CNS, and promotes survival and regeneration in the injured adult optic nerve and spinal cord. Moreover, lowering cholesterol disrupts rafts and restores locomotor function after spinal cord injury. These data reveal a unified strategy to promote both survival and regeneration in the CNS.

  20. A biochemical basis for induction of retina regeneration by antioxidants.

    Science.gov (United States)

    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.

  1. Impaired Muscle Regeneration in Ob/ob and Db/db Mice

    Directory of Open Access Journals (Sweden)

    Mai-Huong Nguyen

    2011-01-01

    Full Text Available In obesity and type 2 diabetes, efficient skeletal muscle repair following injury may be required, not only for restoring muscle structure and function, but also for maintaining exercise capacity and insulin sensitivity. The hypothesis of this study was that muscle regeneration would be impaired in ob/ob and db/db mice, which are common mouse models of obesity and type 2 diabetes. Muscle injury was produced by cardiotoxin injection, and regeneration was assessed by morphological and immunostaining techniques. Muscle regeneration was delayed in ob/ob and db/db mice, but not in a less severe model of insulin resistance – feeding a high-fat diet to wild-type mice. Angiogenesis, cell proliferation, and myoblast accumulation were also impaired in ob/ob and db/db mice, but not the high-fat diet mice. The impairments in muscle regeneration were associated with impaired macrophage accumulation; macrophages have been shown previously to be required for efficient muscle regeneration. Impaired regeneration in ob/ob and db/db mice could be due partly to the lack of leptin signaling, since leptin is expressed both in damaged muscle and in cultured muscle cells. In summary, impaired muscle regeneration in ob/ob and db/db mice was associated with reduced macrophage accumulation, angiogenesis, and myoblast activity, and could have implications for insulin sensitivity in the skeletal muscle of obese and type 2 diabetic patients.

  2. Modeling regeneration responses of big sagebrush (Artemisia tridentata) to abiotic conditions

    Science.gov (United States)

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2014-01-01

    Ecosystems dominated by big sagebrush, Artemisia tridentata Nuttall (Asteraceae), which are the most widespread ecosystems in semiarid western North America, have been affected by land use practices and invasive species. Loss of big sagebrush and the decline of associated species, such as greater sage-grouse, are a concern to land managers and conservationists. However, big sagebrush regeneration remains difficult to achieve by restoration and reclamation efforts and there is no regeneration simulation model available. We present here the first process-based, daily time-step, simulation model to predict yearly big sagebrush regeneration including relevant germination and seedling responses to abiotic factors. We estimated values, uncertainty, and importance of 27 model parameters using a total of 1435 site-years of observation. Our model explained 74% of variability of number of years with successful regeneration at 46 sites. It also achieved 60% overall accuracy predicting yearly regeneration success/failure. Our results identify specific future research needed to improve our understanding of big sagebrush regeneration, including data at the subspecies level and improved parameter estimates for start of seed dispersal, modified wet thermal-time model of germination, and soil water potential influences. We found that relationships between big sagebrush regeneration and climate conditions were site specific, varying across the distribution of big sagebrush. This indicates that statistical models based on climate are unsuitable for understanding range-wide regeneration patterns or for assessing the potential consequences of changing climate on sagebrush regeneration and underscores the value of this process-based model. We used our model to predict potential regeneration across the range of sagebrush ecosystems in the western United States, which confirmed that seedling survival is a limiting factor, whereas germination is not. Our results also suggested that modeled

  3. Shining Light on Nanotechnology to Help Repair and Regeneration

    Science.gov (United States)

    Gupta, Asheesh; Avci, Pinar; Sadasivam, Magesh; Chandran, Rakkiyappan; Parizotto, Nivaldo; Vecchio, Daniela; Antunes-Melo, Wanessa C; Dai, Tianhong; Chiang, Long Y.; Hamblin, Michael R.

    2012-01-01

    Phototherapy can be used in two completely different but complementary therapeutic applications. While low level laser (or light) therapy (LLLT) uses red or near-infrared light alone to reduce inflammation, pain and stimulate tissue repair and regeneration, photodynamic therapy (PDT) uses the combination of light plus non-toxic dyes (called photosensitizers) to produce reactive oxygen species that can kill infectious microorganisms and cancer cells or destroy unwanted tissue (neo-vascularization in the choroid, atherosclerotic plaques in the arteries). The recent development of nanotechnology applied to medicine (nanomedicine) has opened a new front of advancement in the field of phototherapy and has provided hope for the development of nanoscale drug delivery platforms for effective killing of pathological cells and to promote repair and regeneration. Despite the well-known beneficial effects of phototherapy and nanomaterials in producing the killing of unwanted cells and promoting repair and regeneration, there are few reports that combine all three elements i.e. phototherapy, nanotechnology and, tissue repair and regeneration. However, these areas in all possible binary combinations have been addressed by many workers. The present review aims at highlighting the combined multi-model applications of phototherapy, nanotechnology and, reparative and regeneration medicine and outlines current strategies, future applications and limitations of nanoscale-assisted phototherapy for the management of cancers, microbial infections and other diseases, and to promote tissue repair and regeneration. PMID:22951919

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

    Science.gov (United States)

    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.

  5. Regeneration of pilot-scale ion exchange columns for hexavalent chromium removal.

    Science.gov (United States)

    Korak, Julie A; Huggins, Richard; Arias-Paic, Miguel

    2017-07-01

    Due to stricter regulations, some drinking water utilities must implement additional treatment processes to meet potable water standards for hexavalent chromium (Cr(VI)), such as the California limit of 10 μg/L. Strong base anion exchange is effective for Cr(VI) removal, but efficient resin regeneration and waste minimization are important for operational, economic and environmental considerations. This study compared multiple regeneration methods on pilot-scale columns on the basis of regeneration efficiency, waste production and salt usage. A conventional 1-Stage regeneration using 2 N sodium chloride (NaCl) was compared to 1) a 2-Stage process with 0.2 N NaCl followed by 2 N NaCl and 2) a mixed regenerant solution with 2 N NaCl and 0.2 N sodium bicarbonate. All methods eluted similar cumulative amounts of chromium with 2 N NaCl. The 2-Stage process eluted an additional 20-30% of chromium in the 0.2 N fraction, but total resin capacity is unaffected if this fraction is recycled to the ion exchange headworks. The 2-Stage approach selectively eluted bicarbonate and sulfate with 0.2 N NaCl before regeneration using 2 N NaCl. Regeneration approach impacted the elution efficiency of both uranium and vanadium. Regeneration without co-eluting sulfate and bicarbonate led to incomplete uranium elution and potential formation of insoluble uranium hydroxides that could lead to long-term resin fouling, decreased capacity and render the resin a low-level radioactive solid waste. Partial vanadium elution occurred during regeneration due to co-eluting sulfate suppressing vanadium release. Waste production and salt usage were comparable for the 1- and 2-Stage regeneration processes with similar operational setpoints with respect to chromium or nitrate elution. Published by Elsevier Ltd.

  6. DIAGNOSTICS AND REGENERATION OF COMMON RAIL INJECTORS

    Directory of Open Access Journals (Sweden)

    Łukasz KONIECZNY

    2015-03-01

    Full Text Available The article presents the methodology of Common Rail injector diagnostic, regeneration and regulation with use of professional test stands. The EPS 815 machine can be used to test and repair all BOSCH injectors fully satisfying the producer requirements and standards. The article describes an example injector diagnosis with use of such test stand and additionally presents appropriate injector regeneration and encoding techniques

  7. Improvement characteristics shown in holistic regeneration of Ballymun toward sustainable community

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeunsook; Lim, Soohyun; Kim, Gunhyoung [Department of Housing and Interior Design, Yonsei University, Seoul (Korea)

    2010-02-15

    Substantial numbers of urban and residential environments constructed in the 20th century are experiencing degeneration and the importance of challenging to revitalize community holistically is getting more seriously recognized. There, however, has been limitation in grasping the holistic regeneration information as urban regeneration usually goes through a long-term and complicated procedure. Yet, the urban and housing regeneration's direction is required to be holistic in the 21st Century. Any precedent case that had tried the holistic regeneration needs to be checked thoroughly and thereby the result needs to be applied to the future attempts as a reference and knowledge base. The purpose of this study was to delineate improvement characteristics that appeared during the course of holistic regeneration in Ballymun of Ireland. This research is an archival research in nature which also used content analysis technique since it deals with reports and newsletters as archival records that were accumulated on a regular base throughout the whole process. The leading projects continued over ten years of improvement were scrutinized in the perspective of physical, social, economic, cultural, and environmental dimensions of regeneration. The main results were, first, a series of improvement activities and projects to regenerate each of five dimensions were delineated for comprehensive understanding. Second, connected patterns for synergistic improvement were identified and patterns were described to show the detailed contents as examples. This study would provide communities that face holistic regeneration, an insight, planning skills, creative and realistic ideas for implementation, thereby empowers planning capability toward holistic regeneration. (author)

  8. A fundamental study of a regenerator for an Ericsson magnetic refrigerator

    International Nuclear Information System (INIS)

    Matsumoto, K.; Ito, T.; Numazawa, T.; Hashimoto, T.; Kuriyama, T.; Nakagome, H.

    1986-01-01

    The authors studied an Ericsson magnetic refrigerator above 20 K. The magnetic working material passes through the regenerator during internal heat transfer processes. In the temperature range above 20 K, a solid is indispensable for a regenerator in need of the large volumetric heat capacity. Therefore lead is used for the testing regenerator. As thermal conduction of gaseous helium is expected to be useful for the heat transfer between the regenerator and the working material, the authors have made the gap between them small in order to achieve good heat transfer. They investigated the heat transfer process between working material and regenerator experimentally in the temperature from 25 K to 55 K

  9. Comparative study of radiosensitivity of normal and regenerating tissues

    International Nuclear Information System (INIS)

    Samokhvalova, H.S.; Popova, M.F.

    1983-01-01

    A comparative study of radiosensitivity of cells of normal and regenerating tissues of bone marrow and spleen has demonstrated that single exposure to X-rays produces a lesser damaging effect on regenerating tissues than on normal ones. The data obtained indicate that the increase in radioresistance of the organism during active regeneration of the haemopoietic organs is due not merely to the increase in the dividing cell pool of these organs but also to qualitative changes in their functional state

  10. Developmental anatomy of blueberry (Vaccinium corymbosum L. ‘Aurora’) shoot regeneration

    Science.gov (United States)

    The culture of Vaccinium corymbosum L. ’Aurora’ leaves on regeneration medium results in the regeneration of adventitious shoots. We present anatomical evidence that these new shoot apices are directly regenerated from the cultured blades. Mounds of densely staining cells, which formed from epidermi...

  11. Static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon.

    Science.gov (United States)

    Nagasawa, Koji; Noguchi, Masahiko; Ikoma, Kazuya; Kubo, Toshikazu

    2008-07-01

    Since tendons show viscoelastic behavior, dynamic viscoelastic properties should be assessed in addition to static biomechanical properties. We evaluated differences between static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon following tenotomy. At 3, 6, or 12 weeks after right Achilles tenotomy, the right (regenerating) and left (control) tendons were collected with the calcaneus from 49 rabbits. A unidirectional failure test and a dynamic viscoelastic test were conducted. Tensile strength and Young's modulus (static biomechanical properties) in the regenerating group at Week 6 were significantly greater than at Week 3, while at Week 12, these were significantly greater than at Week 6. However, even at Week 12, both parameters were less than in the control group. The value of tan delta represents dynamic viscoelasticity, a smaller tan delta indicates greater elasticity. tan delta for the regenerating group was significantly greater than for the control group at Week 3, but regenerating and control groups did not significantly differ at Week 6. No marked change was seen from Weeks 6 to 12 in the regenerating group, and no significant difference in tan delta was evident between the regenerating and control groups at Week 12. Dynamic biomechanical properties of regenerating rabbit Achilles tendons may improve more rapidly than static biomechanical properties. Ability to tolerate dynamic movement in the healing Achilles tendon may improve more rapidly than ability to withstand static stresses.

  12. Down-regulate of Djrfc2 causes tissues hypertrophy during planarian regeneration.

    Science.gov (United States)

    Guo, Qi; Zhao, Guixia; Ni, Jiajia; Guo, Yanan; Zhang, Yizhe; Tian, Qingnan; Zhang, Shoutao

    2017-11-25

    Planarians are an ideal model organism for regeneration research due to their amazing ability to regenerate. DNA replication is crucial for genome stability. Replication factor C (RFC), which is a replication factor C-like complex and plays an important role during DNA replication in eukaryotes, has been reported as a wound response factor during planarian regeneration. However, how RFC controls regeneration in planarians by regulating DNA replication remains to be explained. Here, we used a two-dimensional electrophoresis (2-DE) proteomic approach to identify differentially expressed proteins in intact and regenerated planarians. Approximately 132 protein spots showed differences between intact and regenerative tissues. We selected 21 significantly expressed protein spots and processed them using TOF MS analysis. Finally, we cloned three of these candidate genes (Djhsp70, Djrfc2, Djfaim), focusing on the function of Djrfc2 during regeneration. We found that the distribution of Djrfc2 tends toward the wound site. RNA interference (RNAi) of Djrfc2 increases the number of dividing cells and the expression level of planarian neoblast marker genes, which may result in hyper-proliferation. Our studies use an available approach to directly study the regeneration dynamic at the protein level and provide further evidence to support a function of Djrfc2 in planarian regeneration. Copyright © 2017. Published by Elsevier Inc.

  13. Callus regeneration from stem explants of Pseudarthira viscida (L ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-01

    Sep 1, 2009 ... regeneration frequency have come from tissue culture work done in ... Table 1. In vitro responses from stem callus of Psudarthria viscida Wight & Arn. Growth .... plantlets regeneration from cotyledonary callus of Tomato.

  14. Development of an efficient plant regeneration protocol for sweet ...

    African Journals Online (AJOL)

    UKZN

    2012-10-18

    Oct 18, 2012 ... explants produced highly recalcitrant callus that did not regenerate into ... Key words: Tissue culture, regeneration, sweet potato, genetic transformation. .... sterilized in 5% (v/v) sodium hypochlorite solution for 20 min and.

  15. Effective regeneration of anode material recycled from scrapped Li-ion batteries

    Science.gov (United States)

    Zhang, Jin; Li, Xuelei; Song, Dawei; Miao, Yanli; Song, Jishun; Zhang, Lianqi

    2018-06-01

    Recycling high-valuable metal elements (such as Li, Ni, Co, Al and Cu elements) from scrapped lithium ion batteries can bring significant economic benefits. However, recycling and reusing anode material has not yet attracted wide attention up to now, due to the lower added-value than the above valuable metal materials and the difficulties in regenerating process. In this paper, a novel regeneration process with significant green advance is proposed to regenerate anode material recycled from scrapped Li-ion batteries for the first time. After regenerated, most acetylene black (AB) and all the styrene butadiene rubber (SBR), carboxymethylcellulose sodium (CMC) in recycled anode material are removed, and the surface of anode material is coated with pyrolytic carbon from phenolic resin again. Finally, the regenerated anode material (graphite with coating layer, residual AB and a little CMC pyrolysis product) is obtained. As expected, all the technical indexs of regenerated anode material exceed that of a midrange graphite with the same type, and partial technical indexs are even closed to that of the unused graphite. The results indicate the effective regeneration of anode material recycled from scrapped Li-ion batteries is really achieved.

  16. Influence of thermal treatment on OSL regeneration in potassium chloride

    International Nuclear Information System (INIS)

    Majgier, Renata; Biernacka, Magdalena; Mandowski, Arkadiusz

    2016-01-01

    Optically stimulated luminescence (OSL) of pure analytical potassium chloride (KCl) prepared in two different forms (crystals and pellets) was studied. The occurrence of regeneration effect (self-renewal of the OSL signal) in the material was examined. The experiments using the variable delay OSL (VD-OSL) method were carried out. Performed measurements allowed to determine time scale of the phenomenon, as well as quantitative changes of regeneration depending on thermal treatment before and after irradiation. Significant increase of the OSL regeneration was noticeable for pellets after the application of the annealing before irradiation, while for crystals a substantial decrease of regeneration was observed. Preheating applied after irradiation caused that self-renewal of OSL signal was drastically reduced or completely suppressed depending on the form of KCl samples. - Highlights: • Optically stimulated luminescence (OSL) of potassium chloride (KCl) was studied. • The measurements were performed using the variable delay OSL method (VD-OSL). • It was found that regeneration of OSL intensity in KCl could be as high as 2000%. • Annealing caused reduction of OSL renewal for crystals and its increase for pellets. • Preheating after irradiation removed or significantly reduced the OSL regeneration.

  17. Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration.

    Science.gov (United States)

    Hu, Lei; Gao, Zhenhua; Xu, Junji; Zhu, Zhao; Fan, Zhipeng; Zhang, Chunmei; Wang, Jinsong; Wang, Songlin

    2017-01-01

    Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS) combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

  18. Delayed liver regeneration after partial hepatectomy in adiponectin knockout mice

    International Nuclear Information System (INIS)

    Ezaki, Hisao; Yoshida, Yuichi; Saji, Yukiko; Takemura, Takayo; Fukushima, Juichi; Matsumoto, Hitoshi; Kamada, Yoshihiro; Wada, Akira; Igura, Takumi; Kihara, Shinji; Funahashi, Tohru; Shimomura, Iichiro; Tamura, Shinji; Kiso, Shinichi; Hayashi, Norio

    2009-01-01

    We previously demonstrated that adiponectin has anti-fibrogenic and anti-inflammatory effects in the liver of mouse models of various liver diseases. However, its role in liver regeneration remains unclear. The aim of this study was to determine the role of adiponectin in liver regeneration. We assessed liver regeneration after partial hepatectomy in wild-type (WT) and adiponectin knockout (KO) mice. We analyzed DNA replication and various signaling pathways involved in cell proliferation and metabolism. Adiponectin KO mice exhibited delayed DNA replication and increased lipid accumulation in the regenerating liver. The expression levels of peroxisome proliferator-activated receptor (PPAR) α and carnitine palmitoyltransferase-1 (CPT-1), a key enzyme in mitochondrial fatty acid oxidation, were decreased in adiponectin KO mice, suggesting possible contribution of altered fat metabolism to these phenomena. Collectively, the present results highlight a new role for adiponectin in the process of liver regeneration.

  19. Serial analysis of gene expression (SAGE) in rat liver regeneration

    International Nuclear Information System (INIS)

    Cimica, Velasco; Batusic, Danko; Haralanova-Ilieva, Borislava; Chen, Yonglong; Hollemann, Thomas; Pieler, Tomas; Ramadori, Giuliano

    2007-01-01

    We have applied serial analysis of gene expression for studying the molecular mechanism of the rat liver regeneration in the model of 70% partial hepatectomy. We generated three SAGE libraries from a normal control liver (NL library: 52,343 tags), from a sham control operated liver (Sham library: 51,028 tags), and from a regenerating liver (PH library: 53,061 tags). By SAGE bioinformatics analysis we identified 40 induced genes and 20 repressed genes during the liver regeneration. We verified temporal expression of such genes by real time PCR during the regeneration process and we characterized 13 induced genes and 3 repressed genes. We found connective tissue growth factor transcript and protein induced very early at 4 h after PH operation before hepatocytes proliferation is triggered. Our study suggests CTGF as a growth factor signaling mediator that could be involved directly in the mechanism of liver regeneration induction

  20. Regenerant arabidopsis lineages display a distinct genome-wide spectrum of mutations conferring variant phenotypes

    KAUST Repository

    Jiang, Caifu

    2011-07-28

    Multicellular organisms can be regenerated from totipotent differentiated somatic cell or nuclear founders [1-3]. Organisms regenerated from clonally related isogenic founders might a priori have been expected to be phenotypically invariant. However, clonal regenerant animals display variant phenotypes caused by defective epigenetic reprogramming of gene expression [2], and clonal regenerant plants exhibit poorly understood heritable phenotypic ("somaclonal") variation [4-7]. Here we show that somaclonal variation in regenerant Arabidopsis lineages is associated with genome-wide elevation in DNA sequence mutation rate. We also show that regenerant mutations comprise a distinctive molecular spectrum of base substitutions, insertions, and deletions that probably results from decreased DNA repair fidelity. Finally, we show that while regenerant base substitutions are a likely major genetic cause of the somaclonal variation of regenerant Arabidopsis lineages, transposon movement is unlikely to contribute substantially to that variation. We conclude that the phenotypic variation of regenerant plants, unlike that of regenerant animals, is substantially due to DNA sequence mutation. 2011 Elsevier Ltd. All rights reserved.

  1. Regenerant arabidopsis lineages display a distinct genome-wide spectrum of mutations conferring variant phenotypes

    KAUST Repository

    Jiang, Caifu; Mithani, Aziz; Gan, Xiangchao; Belfield, Eric J.; Klingler, John  P.; Zhu, Jian-Kang; Ragoussis, Jiannis; Mott, Richard; Harberd, Nicholas  P.

    2011-01-01

    Multicellular organisms can be regenerated from totipotent differentiated somatic cell or nuclear founders [1-3]. Organisms regenerated from clonally related isogenic founders might a priori have been expected to be phenotypically invariant. However, clonal regenerant animals display variant phenotypes caused by defective epigenetic reprogramming of gene expression [2], and clonal regenerant plants exhibit poorly understood heritable phenotypic ("somaclonal") variation [4-7]. Here we show that somaclonal variation in regenerant Arabidopsis lineages is associated with genome-wide elevation in DNA sequence mutation rate. We also show that regenerant mutations comprise a distinctive molecular spectrum of base substitutions, insertions, and deletions that probably results from decreased DNA repair fidelity. Finally, we show that while regenerant base substitutions are a likely major genetic cause of the somaclonal variation of regenerant Arabidopsis lineages, transposon movement is unlikely to contribute substantially to that variation. We conclude that the phenotypic variation of regenerant plants, unlike that of regenerant animals, is substantially due to DNA sequence mutation. 2011 Elsevier Ltd. All rights reserved.

  2. Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration.

    Science.gov (United States)

    LoCascio, Samuel A; Lapan, Sylvain W; Reddien, Peter W

    2017-02-27

    Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Understanding Liver Regeneration: From Mechanisms to Regenerative Medicine.

    Science.gov (United States)

    Gilgenkrantz, Hélène; Collin de l'Hortet, Alexandra

    2018-04-16

    Liver regeneration is a complex and unique process. When two-thirds of a mouse liver is removed, the remaining liver recovers its initial weight in approximately 10 days. The understanding of the mechanisms responsible for liver regeneration may help patients needing large liver resections or transplantation and may be applied to the field of regenerative medicine. All differentiated hepatocytes are capable of self-renewal, but different subpopulations of hepatocytes seem to have distinct proliferative abilities. In the setting of chronic liver diseases, a ductular reaction ensues in which liver progenitor cells (LPCs) proliferate in the periportal region. Although these LPCs have the capacity to differentiate into hepatocytes and biliary cells in vitro, their ability to participate in liver regeneration is far from clear. Their expansion has even been associated with increased fibrosis and poorer prognosis in chronic liver diseases. Controversies also remain on their origin: lineage studies in experimental mouse models of chronic injury have recently suggested that these LPCs originate from hepatocyte dedifferentiation, whereas in other situations, they seem to come from cholangiocytes. This review summarizes data published in the past 5 years in the liver regeneration field, discusses the mechanisms leading to regeneration disruption in chronic liver disorders, and addresses the potential use of novel approaches for regenerative medicine. Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  4. Bionanomaterials for skin regeneration

    CERN Document Server

    Leonida, Mihaela D

    2016-01-01

    This book gives a concise overview of bionanomaterials with applications for skin regeneration. The advantages and challenges of nanoscale materials are covered in detail, giving a basic view of the skin structure and conditions that require transdermal or topical applications. Medical applications, such as wound healing, care for burns, skin disease, and cosmetic care, such as aging of the skin and photodamage, and how they benefit from bionanomaterials, are described in detail. A final chapter is devoted to the ethical and social issues related to the use of bionanomaterials for skin regeneration. This is an ideal book for researchers in materials science, medical scientists specialized in dermatology, and cosmetic chemists working in formulations. It can also serve as a reference for nanotechnologists, dermatologists, microbiologists, engineers, and polymer chemists, as well as students studying in these fields.

  5. Plantlet regeneration potential from seedling explants of vitegnus (Vitex agnus castus).

    Science.gov (United States)

    Chamandoosti, F

    2007-11-15

    In this research a simple and repeatable method for regeneration of a important medicinal plant (Vitex agnus castus) described. Different seedling explants such as hypocotyl, cotyledon, root and apical meristem were cultured in MS basal media with different kinds and concentrations of PGRs. Root and apical meristem explants were the only explants that have regeneration whole plantlets potential. It was interesting that regeneration whole plantlets from root and apical meristem explants have different developmental pathways. Whole plantlets from apical meristem explants regenerated by passing phase callusing whereas regeneration whole plantlets from root was direct and without phase callusing. This subject implies that we can have many manipulation possibilities in order to different objects of tissue culture by selecting different explants in vitegnus.

  6. Improvement of two-stage GM refrigerator performance using a hybrid regenerator

    International Nuclear Information System (INIS)

    Ke, G.; Makuuchi, H.; Hashimoto, T.; Onishi, A.; Li, R.; Satoh, T.; Kanazawa, Y.

    1994-01-01

    To improve the performance of two-stage GM refrigerators, a hybrid regenerator with magnetic materials of Er 3 Ni and ErNi 0.9 Co 0.1 was used in the 2nd stage regenerator because of its large heat exchange capacity. The largest refrigeration capacity achieved with the hybrid regenerator was 0.95W at helium liquefied temperature of 4.2K. This capacity is 15.9% greater than the 0.82W refrigerator with only Er 3 Ni as the 2nd regenerator material. Use of the hybrid regenerator not only increases the refrigeration capacity at 4.2K, but also allows the 4K GM refrigerator to be used with large 1st stage refrigeration capacity, thus making it more practical

  7. Regenerating reptile retinas: a comparative approach to restoring retinal ganglion cell function.

    Science.gov (United States)

    Williams, D L

    2017-02-01

    Transection or damage to the mammalian optic nerve generally results in loss of retinal ganglion cells by apoptosis. This cell death is seen less in fish or amphibians where retinal ganglion cell survival and axon regeneration leads to recovery of sight. Reptiles lie somewhere in the middle of this spectrum of nerve regeneration, and different species have been reported to have a significant variation in their retinal ganglion cell regenerative capacity. The ornate dragon lizard Ctenophoris ornatus exhibits a profound capacity for regeneration, whereas the Tenerife wall lizard Gallotia galloti has a more variable response to optic nerve damage. Some individuals regain visual activity such as the pupillomotor responses, whereas in others axons fail to regenerate sufficiently. Even in Ctenophoris, although the retinal ganglion cell axons regenerate adequately enough to synapse in the tectum, they do not make long-term topographic connections allowing recovery of complex visually motivated behaviour. The question then centres on where these intraspecies differences originate. Is it variation in the innate ability of retinal ganglion cells from different species to regenerate with functional validity? Or is it variances between different species in the substrate within which the nerves regenerate, the extracellular environment of the damaged nerve or the supporting cells surrounding the regenerating axons? Investigations of retinal ganglion cell regeneration between different species of lower vertebrates in vivo may shed light on these questions. Or perhaps more interesting are in vitro studies comparing axon regeneration of retinal ganglion cells from various species placed on differing substrates.

  8. In vitro regeneration of selected commercial Tanzanian open ...

    African Journals Online (AJOL)

    Yomi

    2012-03-15

    Mar 15, 2012 ... regenerated in vitro using immature zygotic embryos as ex-plants. Callus induction .... Ears were harvested between 12 to 16 days post pollination depending on .... After 28 days of culture on CMM, a mass of dedifferentiated cells .... showed high regeneration ability compared to Situka M-1 that had good ...

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O 3 ) 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 O 3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O 3 regeneration. O 3 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 O 3 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 O 3 regeneration has a lower weight loss than DBD plasma regeneration

  11. Sensory hair cell regeneration in the zebrafish lateral line.

    Science.gov (United States)

    Lush, Mark E; Piotrowski, Tatjana

    2014-10-01

    Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling, and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. Copyright © 2014 Wiley Periodicals, Inc.

  12. SENSORY HAIR CELL REGENERATION IN THE ZEBRAFISH LATERAL LINE

    Science.gov (United States)

    Lush, Mark E.; Piotrowski, Tatjana

    2014-01-01

    Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. PMID:25045019

  13. Are fingernails a key to unlocking the puzzle of mammalian limb regeneration?

    Science.gov (United States)

    Lehoczky, Jessica A

    2017-06-01

    Some mammalian digit tips, including those of mice and human children, can regenerate following amputation, whereas mammalian limb regeneration does not occur. One major difference between the digit tip and the rest of the limb is the presence of the nail, which is necessary for this type of regeneration. This couples well with the finding that canonical Wnt signalling and Lgr6, an agonist of Wnt signalling that marks nail stem cells, are necessary for digit tip regeneration. This viewpoint essay discusses the role of the nail in digit tip regeneration and explores whether nail stem cells and their presumptive niche can be solely accountable for why regeneration is possible in the digit tip, but not the rest of the limb. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Bex1 knock out mice show altered skeletal muscle regeneration

    International Nuclear Information System (INIS)

    Koo, Jae Hyung; Smiley, Mark A.; Lovering, Richard M.; Margolis, Frank L.

    2007-01-01

    Bex1 and Calmodulin (CaM) are upregulated during skeletal muscle regeneration. We confirm this finding and demonstrate the novel finding that they interact in a calcium-dependent manner. To study the role of Bex1 and its interaction with CaM in skeletal muscle regeneration, we generated Bex1 knock out (Bex1-KO) mice. These mice appeared to develop normally and are fertile, but displayed a functional deficit in exercise performance compared to wild type (WT) mice. After intramuscular injection of cardiotoxin, which causes extensive and reproducible myotrauma followed by recovery, regenerating muscles of Bex1-KO mice exhibited elevated and prolonged cell proliferation, as well as delayed cell differentiation, compared to WT mice. Thus, our results provide the first evidence that Bex1-KO mice show altered muscle regeneration, and allow us to propose that the interaction of Bex1 with Ca 2+ /CaM may be involved in skeletal muscle regeneration

  15. Designing reliability into high-effectiveness industrial gas turbine regenerators

    International Nuclear Information System (INIS)

    Valentino, S.J.

    1979-01-01

    The paper addresses the measures necessary to achieve a reliable regenerator design that can withstand higher temperatures (1000-1200 F) and many start and stop cycles - conditions encountered in high-efficiency operation in pipeline applications. The discussion is limited to three major areas: (1) structural analysis of the heat exchanger core - the part of the regenerator that must withstand the higher temperatures and cyclic duty (2) materials data and material selection and (3) a comprehensive test program to demonstrate the reliability of the regenerator. This program includes life-cycle tests, pressure containment in fin panels, core-to-core joint structural test, bellows pressure containment test, sliding pad test, core gas-side passage flow distribution test, and production test. Today's regenerators must have high cyclic life capability, stainless steel construction, and long fault-free service life of 120,000 hr

  16. Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

    OpenAIRE

    Hu, Lei; Gao, Zhenhua; Xu, Junji; Zhu, Zhao; Fan, Zhipeng; Zhang, Chunmei; Wang, Jinsong; Wang, Songlin

    2017-01-01

    Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental p...

  17. Extracting metals directly from metal oxides

    International Nuclear Information System (INIS)

    Wai, C.M.; Smart, N.G.; Phelps, C.

    1997-01-01

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of β-diketones, halogenated β-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs

  18. Sustainable Regeneration of Nanoparticle Enhanced Activated Carbon in Water

    Science.gov (United States)

    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 ...

  19. Fenton-Driven Regeneration of MTBE-spent Granular Activated Carbon

    Science.gov (United States)

    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...

  20. Solving local problems through local involvement? Experiences from Danish Urban Regeneration

    DEFF Research Database (Denmark)

    Jensen, Jesper Ole

    -down approaches or massive public subsidies, the public regeneration schemes from the last decade have increasingly emphasized the need for involving local actors in the urban regeneration e.g. through partnerships, network building, involvement and participation of local actors and institutions, and financially...... agenda, and what can be learned from the development so far. Although ‘local involvement’ is a commonly used term in various urban regeneration programs, it can have many different meanings and implications. Therefore, the paper will discuss local involvement in the urban regeneration based on four...

  1. Plant regeneration protocol of Andrographis paniculata (Burm. f ...

    African Journals Online (AJOL)

    Plant regeneration protocol of Andrographis paniculata (Burm. f.) - an important medicinal plant. ... Inclusion of 1.0 mg/l 1-naphthalene acetic acid (NAA) in the culture medium along with BA + Ads promoted a higher rate of shoot bud regeneration. Maximum mean number of shoot bud per explant (28.6) was achieved on the ...

  2. Non-Uniform Heat Transfer in Thermal Regenerators

    DEFF Research Database (Denmark)

    Jensen, Jesper Buch

    , a numerical model, which simulates a single-blow operation in a parallel-plate regenerator, was developed and used to model the heat transfer under various conditions. In addition to the modeling of the heat transfer, a series of experiments on passive regenerators with non-uniform, but precisely controlled....... Additionally, the experiments gave real comparative results, whereas the model to a certain degree more served to provide insight to the heat transfer processes taking place inside the regenera- tors, something that would be - if not impossible - then highly impractical to do experimentally. It has been found......This thesis presents investigations on the heat transfer in complex heat ex- changers in general and in regenerative heat exchangers (regenerators) in par- ticular. The motivation for this work is a result of inconsistencies obeserved in the results from a series of experiments on active magnetic...

  3. Facilitating Oak and Hickory Regeneration in Mature Central Hardwood Forests

    Directory of Open Access Journals (Sweden)

    Eric J. Holzmueller

    2014-12-01

    Full Text Available Advanced oak and hickory regeneration is often absent in mature oak-hickory forests in the Central Hardwood Region of the United States. Prescribed fire and thinning, alone and combined, are commonly prescribed silvicultural treatments that are recommended to initiate the regeneration process. This study examined the regeneration response in three mature oak stands following four treatments: (1 thin, (2 burn, (3 thinning and burning, or (4 no treatment (control. Ten years after initial treatment, results indicate that oak and hickory seedlings had greater height and diameter in the thinning and burning treatment compared to the control and that this treatment may help facilitate desirable regeneration in mature oak-hickory forests.

  4. Increase of corneal epithelium cell radioresistance during regeneration

    International Nuclear Information System (INIS)

    Popova, M.F.; Bulyakova, N.V.; Azarova, V.S.

    1985-01-01

    A comparative study of the radiosensitivity of the normal and regenerating cornea epithelium of C 57 Bl mice was performed on the cellular level, the duration of the cell cycle being taken into account. Criteria of radiation injuries were the number of chromosome aberrations, mitotic index and duration of mitotic block. The anterior part of the head was irradiated singly with 1.75, 3.5 or 7.0 Gy and also repeatedly 3.5 + 3.5 at a 24-hours interval. The corneas were fixed 2, 4, 6, 12, 24, 48, 72 and 96 hours after irradiation. In all cases of irradiated mice the regenerating epithelium showed a shorter mitotic block and significantly lower cytogenetic injury as compared with the controls. Effects of fractionated irradiation were only shown in the regenerating epithelium. The results obtained indicate that regenerating epithelium cells of the cornea are significantly more radioresistant than normal epithelium due to activation of post-radiation recovery, and also, possibly, due to an increase in the content of endogenous radioprotectors. (author)

  5. Kaolinite adsorption-regeneration system for dyestuff treatment by Fenton based processes.

    Science.gov (United States)

    Rosales, Emilio; Anasie, Delia; Pazos, Marta; Lazar, Iuliana; Sanromán, M Angeles

    2018-05-01

    The regeneration and reuse of adsorbents is a subject of interest nowadays in order to reduce the pollution and the wastes generated in the adsorption wastewater treatment. In this work, the regeneration of the spent kaolinite by different advanced oxidation processes (Fenton, electro-Fenton and electrokinetic-Fenton) was evaluated. Initially, it was confirmed the ability of a low cost clayey material, kaolinite, for the adsorption of model dye such as Rhodamine B showing Freundlich isotherm fitting. Then, the regeneration and consequent degradation of the pollutant in the adsorbent by Fenton based processes was carried out. The role of different parameters affecting the regeneration process (H 2 O 2 :Fe 2+ ratio, liquid:solid ratio) were evaluated. Working at 100:1 H 2 O 2 :Fe 2+ ratio and 30min near complete dye removal (around 97%) from kaolinite was obtained by Fenton treatment. After that, a two-stage treatment for adsorption-regeneration was evaluated during five treatment cycles demonstrating its viability for regeneration of the adsorbent through dye degradation. Based on the successful application of Fenton technique, the improvement of the treatment by electro-Fenton and electrokinetic-Fenton were studied for different solid:liquid ratios achieving satisfactory regeneration values. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Spent oxide fuel regeneration by crystallization in molybdate melts

    International Nuclear Information System (INIS)

    Ustinov, O.A.; Sukhanov, L.P.; Yakunin, S.A.

    2006-01-01

    Paper describes a procedure to regenerate spent oxide fuel by its crystallization in molybdate melts. Paper presents the process procedures to regenerate spent fuel of both fast and thermal neutron reactors. One analyzes the advantages of the elaborated procedure [ru

  7. Advanced Scaffolds for Dental Pulp and Periodontal Regeneration.

    Science.gov (United States)

    Bottino, Marco C; Pankajakshan, Divya; Nör, Jacques E

    2017-10-01

    No current therapy promotes root canal disinfection and regeneration of the pulp-dentin complex in cases of pulp necrosis. Antibiotic pastes used to eradicate canal infection negatively affect stem cell survival. Three-dimensional easy-to-fit antibiotic-eluting nanofibers, combined with injectable scaffolds, enriched or not with stem cells and/or growth factors, may increase the likelihood of achieving predictable dental pulp regeneration. Periodontitis is an aggressive disease that impairs the integrity of tooth-supporting structures and may lead to tooth loss. The latest advances in membrane biomodification to endow needed functionalities and technologies to engineer patient-specific membranes/constructs to amplify periodontal regeneration are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Protoplast formation and regeneration in Lactobacillus delbrueckii

    OpenAIRE

    Singhvi, Mamta; Joshi, Dipti; Gaikaiwari, Shalaka; Gokhale, Digambar V.

    2010-01-01

    Method for production and regeneration of Lactobacillus delbrueckii protoplasts are described. The protoplasts were obtained by treatment with a mixture of lysozyme and mutanolysin in protoplast buffer at pH 6.5 with different osmotic stabilizers. The protoplasts were regenerated on deMan, Rogosa and Sharpe (MRS) with various osmotic stabilizers. Maximum protoplast formation was obtained in protoplast buffer with sucrose as an osmotic stabilizer using a combination of lysozyme (1 mg/ml) and m...

  9. Theoretical storage capacity for solar air pretreatment liquid collector/regenerator

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Donggen; Zhang, Xiaosong; Yin, Yonggao [School of Energy and Environment, Southeast University, Nanjing 210096 (China)

    2008-08-15

    A new liquid regeneration equipment - solar air pretreatment collector/regenerator for liquid desiccant cooling system is put forward in this paper, which is preferable to solution regeneration in hot and moist climate in South China. The equipment can achieve liquid regeneration in lower temperature. When the solution and the air are in ''match'' state in collector/regenerator, a match air to salt mass ratio ASMR* is found by theoretical study in which there is the largest theoretical storage capacity SC{sub max}. At T{sub r} = 60{sup o}C and X{sub in} 2.33 kg/kg, theoretical calculation discovers when Y{sub in} drops from 29 to 14 g/kg, the SC{sub max} increase 50% compared with ASMR{sup *} being around 26-27. After two new concepts of the effective solution proportion (EPS) and the effective storage capacity (ESC) are defined, it is found by theoretical calculation that when ESP drops from 100% to 67%, ESC raises lowly, not drops and liquid outlet concentration C{sub str.sol} increases from 40% to 49% in which its increment totals to 90%. All these data explain fully that air pretreatment liquid regeneration equipment enables to improve the performance of liquid desiccant cooling system. (author)

  10. Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

    Directory of Open Access Journals (Sweden)

    Lei Hu

    2017-01-01

    Full Text Available Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

  11. Enamel Regeneration - Current Progress and Challenges

    Science.gov (United States)

    Baswaraj; H.K, Navin; K.B, Prasanna

    2014-01-01

    Dental Enamel is the outermost covering of teeth. It is hardest mineralized tissue present in the human body. Enamel faces the challenge of maintaining its integrity in a constant demineralization and remineralization within the oral environment and it is vulnerable to wear, damage, and decay. It cannot regenerate itself, because it is formed by a layer of cells that are lost after the tooth eruption. Conventional treatment relies on synthetic materials to restore lost enamel that cannot mimic natural enamel. With advances in material science and understanding of basic principles of organic matrix mediated mineralization paves a way for formation of synthetic enamel. The knowledge of enamel formation and understanding of protein interactions and their gene products function along with the isolation of postnatal stem cells from various sources in the oral cavity, and the development of smart materials for cell and growth factor delivery, makes possibility for biological based enamel regeneration. This article will review the recent endeavor on biomimetic synthesis and cell based strategies for enamel regeneration. PMID:25386548

  12. Role of annexin gene and its regulation during zebrafish caudal fin regeneration.

    Science.gov (United States)

    Saxena, Sandeep; Purushothaman, Sruthi; Meghah, Vuppalapaty; Bhatti, Bhawna; Poruri, Akhila; Meena Lakshmi, Mula G; Sarath Babu, Nukala; Narasimha Murthy, Ch Lakshmi; Mandal, Komal K; Kumar, Arvind; Idris, Mohammed M

    2016-05-01

    The molecular mechanism of epimorphic regeneration is elusive due to its complexity and limitation in mammals. Epigenetic regulatory mechanisms play a crucial role in development and regeneration. This investigation attempted to reveal the role of epigenetic regulatory mechanisms, such as histone H3 and H4 lysine acetylation and methylation during zebrafish caudal fin regeneration. It was intriguing to observe that H3K9,14 acetylation, H4K20 trimethylation, H3K4 trimethylation and H3K9 dimethylation along with their respective regulatory genes, such as GCN5, SETd8b, SETD7/9, and SUV39h1, were differentially regulated in the regenerating fin at various time points of post-amputation. Annexin genes have been associated with regeneration; this study reveals the significant up-regulation of ANXA2a and ANXA2b transcripts and their protein products during the regeneration process. Chromatin immunoprecipitation and PCR analysis of the regulatory regions of the ANXA2a and ANXA2b genes demonstrated the ability to repress two histone methylations, H3K27me3 and H4K20me3, in transcriptional regulation during regeneration. It is hypothesized that this novel insight into the diverse epigenetic mechanisms that play a critical role during the regeneration process may help to strategize the translational efforts, in addition to identifying the molecules involved in vertebrate regeneration. © 2016 by the Wound Healing Society.

  13. Farnesoid X receptor, the bile acid sensing nuclear receptor, in liver regeneration

    Directory of Open Access Journals (Sweden)

    Guodong Li

    2015-03-01

    Full Text Available The liver is unique in regenerative potential, which could recover the lost mass and function after injury from ischemia and resection. The underlying molecular mechanisms of liver regeneration have been extensively studied in the past using the partial hepatectomy (PH model in rodents, where 2/3 PH is carried out by removing two lobes. The whole process of liver regeneration is complicated, orchestrated event involving a network of connected interactions, which still remain fully elusive. Bile acids (BAs are ligands of farnesoid X receptor (FXR, a nuclear receptor of ligand-activated transcription factor. FXR has been shown to be highly involved in liver regeneration. BAs and FXR not only interact with each other but also regulate various downstream targets independently during liver regeneration. Moreover, recent findings suggest that tissue-specific FXR also contributes to liver regeneration significantly. These novel findings suggest that FXR has much broader role than regulating BA, cholesterol, lipid and glucose metabolism. Therefore, these researches highlight FXR as an important pharmaceutical target for potential use of FXR ligands to regulate liver regeneration in clinic. This review focuses on the roles of BAs and FXR in liver regeneration and the current underlying molecular mechanisms which contribute to liver regeneration.

  14. Antid aq iabetic queous c activ s leaf e ity and extract d acute t of Ve ...

    African Journals Online (AJOL)

    SAM

    its resolutions the support of national traditional medicine program, drawing attention ... Plants have always been an exemplary source of drugs and many of the ... leaves and stem have a bitter taste when chewed. Its leaves were ... Phytochemical tests on the extract ..... cells could have started a gradual regeneration, hence.

  15. Research Note Effects of previous cultivation on regeneration of ...

    African Journals Online (AJOL)

    We investigated the effects of previous cultivation on regeneration potential under miombo woodlands in a resettlement area, a spatial product of Zimbabwe's land reforms. We predicted that cultivation would affect population structure, regeneration, recruitment and potential grazing capacity of rangelands. Plant attributes ...

  16. PLETHORA genes control regeneration by a two-step mechanism

    NARCIS (Netherlands)

    Kareem, Abdul; Durgaprasad, Kavya; Sugimoto, Kaoru; Du, Yujuan; Pulianmackal, Ajai J.; Trivedi, Zankhana B.; Abhayadev, Pazhoor V.; Pinon, Violaine; Meyerowitz, Elliot M.; Scheres, Ben; Prasad, Kalika

    2015-01-01

    Summary Regeneration, a remarkable example of developmental plasticity displayed by both plants and animals, involves successive developmental events driven in response to environmental cues. Despite decades of study on the ability of the plant tissues to regenerate a complete fertile shoot

  17. Epimorphic regeneration approach to tissue replacement in adult mammals

    Science.gov (United States)

    Urodeles and fetal mammals are capable of impressive epimorphic regeneration in a variety of tissues, whereas the typical default response to injury in adult mammals consists of inflammation and scar tissue formation. One component of epimorphic regeneration is the recruitment of resident progenitor...

  18. Regenerable Carbon Filter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A Regenerable Carbon Filter (RCF) is proposed for the removal of carbonaceous particulate matter produced in Environmental Control and Life Support (ECLS) processes....

  19. Light requirement for shoot regeneration in horseradish hairy roots.

    Science.gov (United States)

    Saitou, T; Kamada, H; Harada, H

    1992-08-01

    Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions.

  20. Bioactive self-assembled peptide nanofibers for corneal stroma regeneration.

    Science.gov (United States)

    Uzunalli, G; Soran, Z; Erkal, T S; Dagdas, Y S; Dinc, E; Hondur, A M; Bilgihan, K; Aydin, B; Guler, M O; Tekinay, A B

    2014-03-01

    Defects in the corneal stroma caused by trauma or diseases such as macular corneal dystrophy and keratoconus can be detrimental for vision. Development of therapeutic methods to enhance corneal regeneration is essential for treatment of these defects. This paper describes a bioactive peptide nanofiber scaffold system for corneal tissue regeneration. These nanofibers are formed by self-assembling peptide amphiphile molecules containing laminin and fibronectin inspired sequences. Human corneal keratocyte cells cultured on laminin-mimetic peptide nanofibers retained their characteristic morphology, and their proliferation was enhanced compared with cells cultured on fibronectin-mimetic nanofibers. When these nanofibers were used for damaged rabbit corneas, laminin-mimetic peptide nanofibers increased keratocyte migration and supported stroma regeneration. These results suggest that laminin-mimetic peptide nanofibers provide a promising injectable, synthetic scaffold system for cornea stroma regeneration. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Study on regeneration of activated carbon by means of electron radiation

    International Nuclear Information System (INIS)

    Zhu Guanghua; Arai, H.; Hosono, M.

    1991-01-01

    The results of regeneration of activated carbon adsorbing sodium lauryl sulfate (SLS) by 2 MeV electron radiation, and the dependence of the regeneration rate of activated carbon on the electron current intensity, the temperature of sample and the atmosphere were reported. It is shown that regeneration of activated carbon by electron radiation is full of promise

  2. Electrically heated particulate filter regeneration methods and systems for hybrid vehicles

    Science.gov (United States)

    Gonze, Eugene V.; Paratore, Jr., Michael J.

    2010-10-12

    A control system for controlling regeneration of a particulate filter for a hybrid vehicle is provided. The system generally includes a regeneration module that controls current to the particulate filter to initiate regeneration. An engine control module controls operation of an engine of the hybrid vehicle based on the control of the current to the particulate filter.

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

    Science.gov (United States)

    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

  4. An evaluation of a new approach to the regeneration of Helichrysum italicum (Roth) G. Don, and the molecular characterization of the variation among sets of differently derived regenerants.

    Science.gov (United States)

    Perrini, Rosaria; Alba, Vittorio; Ruta, Claudia; Morone-Fortunato, Irene; Blanco, Antonio; Montemurro, Cinzia

    2009-01-01

    A protocol for the induction of regeneration from leaves of Helichrysum italicum was established. Calli were found to form on the basal medium only when it was supplemented with thidiazuron (TDZ) alone or in combination with naphthalene acetic acid (NAA), with a percentage ranking of at least 80%. The hormone-free medium showed the highest percentage of shoot regeneration (62%) even though no callus formed. AFLP markers were employed to verify tissue culture-induced variation in the regenerated plantlets obtained by direct shoot regeneration or the indirect shoot regeneration process (callus formation). Seven out of the eleven AFLP primer pairs yielded polymorphic patterns. The average number of fragments per primer pair was 64.1. Singletons were represented by 12 (2.7%) fragments. Student's T-test was performed both on the average number of shared fragments and on the nucleotide diversity, and no significant statistical difference was observed between the two regeneration treatments.

  5. Biochemical and Molecular Study of Carpobrotus edulis Bioactive Properties and Their Effects on Dugesia sicula (Turbellaria, Tricladida) Regeneration.

    Science.gov (United States)

    Meddeb, Emna; Charni, Mohamed; Ghazouani, Tesnime; Cozzolino, Autilia; Fratianni, Florinda; Raboudi, Faten; Nazzaro, Filomena; Fattouch, Sami

    2017-07-01

    The traditional medicinal properties of Carpobrotus edulis are well recognized, particularly in Tunisia where it is used for wound healing. Thus, in this study, biochemical and molecular properties of its leaves' bioactive aqueous-acetone extract were investigated. The total phenolic content (TPC) of the extract was estimated to be 184 ± 5 mg/100 g of fresh matter (FM). The qualitative and quantitative polyphenolic profile was determined by ultra performance liquid chromatography with diode array detection (UPLC-DAD) and showed that chlorogenic acid was the major compound (43.7%). The extract exhibits potent antioxidant capacities with IC50 = 56.19 and 58.91 μg/ml, as accessed via the anionic DPPH and cationic ABTS radical scavenging assays, respectively. The extract has high antibacterial properties, especially against the Gram+ Staphylococcus aureus and Bacillus cereus strains. To investigate the extract effect on regeneration, the flatworm Dugesia sicula Lepori, 1948, was used as a model. The macroscopic analysis of planarian cultures in ordinary medium containing phenolic extract at non-toxic concentrations illustrated that the extract caused morphological changes. Additionally, the molecular study through the fluorescence-activated cell sorting (FACS) technique showed that C. edulis polyphenols can harm the stem cells' development. These results emphasize the ecotoxicological impact of phenolic rejections in the environment on flatworms' physiology.

  6. Review: peripheral nerve regeneration using non-tubular alginate gel crosslinked with covalent bonds.

    Science.gov (United States)

    Hashimoto, Tadashi; Suzuki, Yoshihisa; Suzuki, Kyoko; Nakashima, Toshihide; Tanihara, Masao; Ide, Chizuka

    2005-06-01

    We have developed a nerve regeneration material consisting of alginate gel crosslinked with covalent bonds. in the first part of this study, we attempted to analyze nerve regeneration through alginate gel in the early stages within 2 weeks. in the second part, we tried to regenerate cat peripheral nerve by using alginate tubular or non-tubular nerve regeneration devices, and compared their efficacies. Four days after surgery, regenerating axons grew without Schwann cell investment through the partially degraded alginate gel, being in direct contact with the alginate without a basal lamina covering. One to 2 weeks after surgery, regenerating axons were surrounded by common Schwann cells, forming small bundles, with some axons at the periphery being partly in direct contact with alginate. At the distal stump, numerous Schwann cells had migrated into the alginate 8-14 days after surgery. Remarkable restorations of the 50-mm gap in cat sciatic nerve were obtained after a long term by using tubular or non-tubular nerve regeneration material consisting mainly of alginate gel. However, there was no significant difference between both groups at electrophysiological and morphological evaluation. Although, nowadays, nerve regeneration materials being marketed mostly have a tubular structure, our results suggest that the tubular structure is not indispensable for peripheral nerve regeneration.

  7. Abiotic factors influencing tropical dry forests regeneration

    Directory of Open Access Journals (Sweden)

    Ceccon Eliane

    2006-01-01

    Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

  8. Concept development of exchange liquid regeneration

    International Nuclear Information System (INIS)

    Mader, D.L.

    1985-08-01

    Concepts are described for regeneration of the intermediate liquid used for isotope exchange in indirect laser isotope separation processes where the laser operates on a process gas distinct from the feed stream. The specific case of regeneration of an exchange liquid consisting of water, sodium hydroxide, and dimethyl sulfoxide for a process to separate deuterium from hydrogen using laser irradiation of trifluoromethane gas is developed. A water feed stream is converted to steam which rises in a chemical process column where it redeuterates a descending flow of exchange liquid without causing significant changes in its chemical composition

  9. Unbiased stereological methods used for the quantitative evaluation of guided bone regeneration

    DEFF Research Database (Denmark)

    Aaboe, Else Merete; Pinholt, E M; Schou, S

    1998-01-01

    The present study describes the use of unbiased stereological methods for the quantitative evaluation of the amount of regenerated bone. Using the principle of guided bone regeneration the amount of regenerated bone after placement of degradable or non-degradable membranes covering defects...

  10. Regeneration in Jatropha curcas: Factors affecting the efficiency of in vitro regeneration

    KAUST Repository

    Sharma, Sweta K.; Kumar, Nitish Chandramohana; Reddy, Muppala P.

    2011-01-01

    Factors influencing in vitro regeneration through direct shoot bud induction from hypocotyl explants of Jatropha curcas were studied in the present investigation. Regeneration in J. curcas was found to be genotype dependent and out of four toxic and one non-toxic genotype studied, non-toxic was least responsive. The best results irrespective of genotype were obtained on the medium containing 0.5mgL-1 TDZ (Thidiazuron) and in vitro hypocotyl explants were observed to have higher regeneration efficiency as compared to ex vitro explant in both toxic and non-toxic genotypes. Adventitious shoot buds could be induced from the distal end of explants in all the genotypes. The number of shoot buds formed and not the number of explants responding to TDZ treatment were significantly affected by the position of the explant on the seedling axis. Explants from younger seedlings (≤15 days) were still juvenile and formed callus easily, whereas the regeneration response declined with increase in age of seedlings after 30 days. Transient reduction of Ca2+ concentrations to 0.22gL-1 in the germination medium increased the number of responding explants.Induced shoot buds, upon transfer to MS medium containing 2mgL-1 Kn (Kinetin) and 1mgL-1 BAP (6-benzylamino purine) elongated. These elongated shoots were further proliferated on MS medium supplemented with 1.5mgL-1 IAA (indole-3-acetic acid) and 0.5mgL-1 BAP and 3.01-3.91cm elongation was achieved after 6 weeks. No genotype specific variance in shoot elongation was observed among the toxic genotypes except the CSMCRI-JC2, which showed reduced response. And for proliferation among the toxic genotypes, CSMCRI-JC4 showed highest number of shoots formed. Among the rest, no significant differences were observed. The elongated shoot could be rooted by pulse treatment on half-strength MS medium supplemented with 2% sucrose, 3mgL-1 IBA (indole-3-butyric acid), 1mgL-1 IAA, 1mgL-1 NAA (α-naphthalene acetic acid) and subsequent transfer on 0

  11. Regeneration in Jatropha curcas: Factors affecting the efficiency of in vitro regeneration

    KAUST Repository

    Sharma, Sweta K.

    2011-07-01

    Factors influencing in vitro regeneration through direct shoot bud induction from hypocotyl explants of Jatropha curcas were studied in the present investigation. Regeneration in J. curcas was found to be genotype dependent and out of four toxic and one non-toxic genotype studied, non-toxic was least responsive. The best results irrespective of genotype were obtained on the medium containing 0.5mgL-1 TDZ (Thidiazuron) and in vitro hypocotyl explants were observed to have higher regeneration efficiency as compared to ex vitro explant in both toxic and non-toxic genotypes. Adventitious shoot buds could be induced from the distal end of explants in all the genotypes. The number of shoot buds formed and not the number of explants responding to TDZ treatment were significantly affected by the position of the explant on the seedling axis. Explants from younger seedlings (≤15 days) were still juvenile and formed callus easily, whereas the regeneration response declined with increase in age of seedlings after 30 days. Transient reduction of Ca2+ concentrations to 0.22gL-1 in the germination medium increased the number of responding explants.Induced shoot buds, upon transfer to MS medium containing 2mgL-1 Kn (Kinetin) and 1mgL-1 BAP (6-benzylamino purine) elongated. These elongated shoots were further proliferated on MS medium supplemented with 1.5mgL-1 IAA (indole-3-acetic acid) and 0.5mgL-1 BAP and 3.01-3.91cm elongation was achieved after 6 weeks. No genotype specific variance in shoot elongation was observed among the toxic genotypes except the CSMCRI-JC2, which showed reduced response. And for proliferation among the toxic genotypes, CSMCRI-JC4 showed highest number of shoots formed. Among the rest, no significant differences were observed. The elongated shoot could be rooted by pulse treatment on half-strength MS medium supplemented with 2% sucrose, 3mgL-1 IBA (indole-3-butyric acid), 1mgL-1 IAA, 1mgL-1 NAA (α-naphthalene acetic acid) and subsequent transfer on 0

  12. Micromanaging cardiac regeneration : Targeted delivery of microRNAs for cardiac repair and regeneration

    NARCIS (Netherlands)

    Kamps, Jan A.A.M.; Krenning, Guido

    2016-01-01

    The loss of cardiomyocytes during injury and disease can result in heart failure and sudden death, while the adult heart has a limited capacity for endogenous regeneration and repair. Current stem cell-based regenerative medicine approaches modestly improve cardiomyocyte survival, but offer

  13. The extraction of CO2 from the atmosphere

    International Nuclear Information System (INIS)

    Hauet, Jean-Pierre

    2014-01-01

    After having indicated some methods which are considered as ridiculous, hazardous or ethically questionable, the author first presents of method of extraction of CO 2 from the atmosphere developed by a research team of the University of Calgary and applied by the Carbon Engineering Company. According to this concept, ambient air is circulated through an air-contactor in which air leaves its CO 2 to a potassium hydroxide flow which transforms into potassium carbonate. This hydroxide is then re-generated by exchange with calcium hydroxide. The thus formed calcium carbonate is finally thermally decomposed to release CO 2 . He also presents the BECCS (Bio-energy with carbon capture and storage) which has been put forward by the IPCC, evokes the cost of the extracted ton of CO 2 and the arguments of the opponents to this method

  14. Regeneration of nitrobenzene-exhausted granular activated carbon by dielectric barrier discharge method

    International Nuclear Information System (INIS)

    Lan, Tian; Gao, Wenli; Li, Zhongjian; Lei, Lecheng

    2013-01-01

    A novel method for the regeneration of nitrobenzene-exhausted granular activated carbon using dielectric barrier discharge (DBD) was proposed in this study. The influence of several parameters including voltage, frequency, and plasma medium on the regeneration efficiency were studied. Under optimum conditions, regeneration efficiency can reach over 80% and remain nearly stable after 5 times of regeneration cycle. The texture characteristic and surface chemistry of Granular Activated Carbon (GAC) samples were also investigated. Analysis shows that the pore volume and specific surface area of regenerated GAC is strongly recovered compared to the exhausted GAC, but the discharge can cause some pores to diminish. Acidic functional groups on GAC's surface especially carboxylic groups had a growing tendency after DBD process. Experimental results show that the regeneration of GAC by DBD method mainly attributes to high active species and thermal effect, while O 3 has minor effect.

  15. EVALUATING THE CULTURE-LED REGENERATION

    Directory of Open Access Journals (Sweden)

    D'Angelo Francesca

    2010-12-01

    Full Text Available The aim of the paper is to propose a new approach to urban planning, evaluating the culture-led regeneration processes. In the last few years, the cultural turn in urban planning played a central role in the urban studies. In this way we try to elaborate a more robust perspective interpreting the complex phenomenology emerging from the culture-led regeneration processes. Within the concept of complexity we discuss about the metabolic process that are the processes necessary to transform energy, material and information in goods and service functional to the complex urban system life. The approach that will be employed is the MuSIASEM that is based on several novel concept and an innovative methods never applied in this research field.

  16. Transplantation of Human Dental Pulp-Derived Stem Cells or Differentiated Neuronal Cells from Human Dental Pulp-Derived Stem Cells Identically Enhances Regeneration of the Injured Peripheral Nerve.

    Science.gov (United States)

    Ullah, Imran; Park, Ju-Mi; Kang, Young-Hoon; Byun, June-Ho; Kim, Dae-Geon; Kim, Joo-Heon; Kang, Dong-Ho; Rho, Gyu-Jin; Park, Bong-Wook

    2017-09-01

    Human dental mesenchymal stem cells isolated from the dental follicle, pulp, and root apical papilla of extracted wisdom teeth have been known to exhibit successful and potent neurogenic differentiation capacity. In particular, human dental pulp-derived stem cells (hDPSCs) stand out as the most prominent source for in vitro neuronal differentiation. In this study, to evaluate the in vivo peripheral nerve regeneration potential of hDPSCs and differentiated neuronal cells from DPSCs (DF-DPSCs), a total of 1 × 10 6 hDPSCs or DF-hDPSCs labeled with PKH26 tracking dye and supplemented with fibrin glue scaffold and collagen tubulization were transplanted into the sciatic nerve resection (5-mm gap) of rat models. At 12 weeks after cell transplantation, both hDPSC and DF-hDPSC groups showed notably increased behavioral activities and higher muscle contraction forces compared with those in the non-cell transplanted control group. In immunohistochemical analysis of regenerated nerve specimens, specific markers for angiogenesis, axonal fiber, and myelin sheath increased in both the cell transplantation groups. Pretransplanted labeled PKH26 were also distinctly detected in the regenerated nerve tissues, indicating that transplanted cells were well-preserved and differentiated into nerve cells. Furthermore, no difference was observed in the nerve regeneration potential between the hDPSC and DF-hDPSC transplanted groups. These results demonstrate that dental pulp tissue is an excellent stem cell source for nerve regeneration, and in vivo transplantation of the undifferentiated hDPSCs could exhibit sufficient and excellent peripheral nerve regeneration potential.

  17. Enhanced regeneration of degraded polymer solar cells by thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pankaj, E-mail: pankaj@mail.nplindia.ernet.in [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Centre for Organic Electronics, Physics, University of Newcastle, Callaghan NSW-2308 (Australia); Bilen, Chhinder; Zhou, Xiaojing; Belcher, Warwick J.; Dastoor, Paul C., E-mail: Paul.Dastoor@newcastle.edu.au [Centre for Organic Electronics, Physics, University of Newcastle, Callaghan NSW-2308 (Australia); Feron, Krishna [Centre for Organic Electronics, Physics, University of Newcastle, Callaghan NSW-2308 (Australia); CSIRO Energy Technology, P. O. Box 330, Newcastle NSW 2300 (Australia)

    2014-05-12

    The degradation and thermal regeneration of poly(3-hexylethiophene) (P3HT):[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) and P3HT:indene-C{sub 60} bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells with a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles.

  18. Spinal cord regeneration: lessons for mammals from non-mammalian vertebrates.

    Science.gov (United States)

    Lee-Liu, Dasfne; Edwards-Faret, Gabriela; Tapia, Víctor S; Larraín, Juan

    2013-08-01

    Unlike mammals, regenerative model organisms such as amphibians and fish are capable of spinal cord regeneration after injury. Certain key differences between regenerative and nonregenerative organisms have been suggested as involved in promoting this process, such as the capacity for neurogenesis and axonal regeneration, which appear to be facilitated by favorable astroglial, inflammatory and immune responses. These traits provide a regenerative-permissive environment that the mammalian spinal cord appears to be lacking. Evidence for the regenerative nonpermissive environment in mammals is given by the fact that they possess neural stem/progenitor cells, which transplanted into permissive environments are able to give rise to new neurons, whereas in the nonpermissive spinal cord they are unable to do so. We discuss the traits that are favorable for regeneration, comparing what happens in mammals with each regenerative organism, aiming to describe and identify the key differences that allow regeneration. This comparison should lead us toward finding how to promote regeneration in organisms that are unable to do so. Copyright © 2013 Wiley Periodicals, Inc.

  19. Administration of RANKL boosts thymic regeneration upon bone marrow transplantation.

    Science.gov (United States)

    Lopes, Noella; Vachon, Hortense; Marie, Julien; Irla, Magali

    2017-06-01

    Cytoablative treatments lead to severe damages on thymic epithelial cells (TECs), which result in delayed de novo thymopoiesis and a prolonged period of T-cell immunodeficiency. Understanding the mechanisms that govern thymic regeneration is of paramount interest for the recovery of a functional immune system notably after bone marrow transplantation (BMT). Here, we show that RANK ligand (RANKL) is upregulated in CD4 + thymocytes and lymphoid tissue inducer (LTi) cells during the early phase of thymic regeneration. Importantly, whereas RANKL neutralization alters TEC recovery after irradiation, ex vivo RANKL administration during BMT boosts the regeneration of TEC subsets including thymic epithelial progenitor-enriched cells, thymus homing of lymphoid progenitors, and de novo thymopoiesis. RANKL increases specifically in LTi cells, lymphotoxin α, which is critical for thymic regeneration. RANKL treatment, dependent on lymphotoxin α, is beneficial upon BMT in young and aged individuals. This study thus indicates that RANKL may be clinically useful to improve T-cell function recovery after BMT by controlling multiple facets of thymic regeneration. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  20. Enhanced regeneration of degraded polymer solar cells by thermal annealing

    International Nuclear Information System (INIS)

    Kumar, Pankaj; Bilen, Chhinder; Zhou, Xiaojing; Belcher, Warwick J.; Dastoor, Paul C.; Feron, Krishna

    2014-01-01

    The degradation and thermal regeneration of poly(3-hexylethiophene) (P3HT):[6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) and P3HT:indene-C 60 bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells with a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles

  1. Effect of coke and catalyst structure on oxidative regeneration of hydroprocessing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. (CANMET, Ottawa, ON (Canada). Energy Research Laboratories)

    1991-04-01

    Two industrial hydroprocessing catalysts used for upgrading an atmospheric residue and a gas oil, respectively were regenerated in a fixed bed using air and 2 vol.% O{sub 2}+N{sub 2} balance mixture. The regeneration in air resulted in a significant sintering of the catalyst's material. The surface area of catalysts regenerated in 2 vol.% O{sub 2} mixture was similar to that of fresh catalysts, whereas a significant loss of surface area was observed after regeneration in air. The X-ray diffraction pattern of catalysts regenerated in 2 vol.% O{sub 2}+N{sub 2} balance mixture was also similar to that of fresh catalysts. 22 refs., 9 figs., 7 tabs.

  2. Lineage tracing of genome-edited alleles reveals high fidelity axolotl limb regeneration.

    Science.gov (United States)

    Flowers, Grant Parker; Sanor, Lucas D; Crews, Craig M

    2017-09-16

    Salamanders are unparalleled among tetrapods in their ability to regenerate many structures, including entire limbs, and the study of this ability may provide insights into human regenerative therapies. The complex structure of the limb poses challenges to the investigation of the cellular and molecular basis of its regeneration. Using CRISPR/Cas, we genetically labelled unique cell lineages within the developing axolotl embryo and tracked the frequency of each lineage within amputated and fully regenerated limbs. This allowed us, for the first time, to assess the contributions of multiple low frequency cell lineages to the regenerating limb at once. Our comparisons reveal that regenerated limbs are high fidelity replicas of the originals even after repeated amputations.

  3. In situ tissue regeneration: chemoattractants for endogenous stem cell recruitment.

    Science.gov (United States)

    Vanden Berg-Foels, Wendy S

    2014-02-01

    Tissue engineering uses cells, signaling molecules, and/or biomaterials to regenerate injured or diseased tissues. Ex vivo expanded mesenchymal stem cells (MSC) have long been a cornerstone of regeneration therapies; however, drawbacks that include altered signaling responses and reduced homing capacity have prompted investigation of regeneration based on endogenous MSC recruitment. Recent successful proof-of-concept studies have further motivated endogenous MSC recruitment-based approaches. Stem cell migration is required for morphogenesis and organogenesis during development and for tissue maintenance and injury repair in adults. A biomimetic approach to in situ tissue regeneration by endogenous MSC requires the orchestration of three main stages: MSC recruitment, MSC differentiation, and neotissue maturation. The first stage must result in recruitment of a sufficient number of MSC, capable of effecting regeneration, to the injured or diseased tissue. One of the challenges for engineering endogenous MSC recruitment is the selection of effective chemoattractant(s). The objective of this review is to synthesize and evaluate evidence of recruitment efficacy by reported chemoattractants, including growth factors, chemokines, and other more recently appreciated MSC chemoattractants. The influence of MSC tissue sources, cell culture methods, and the in vitro and in vivo environments is discussed. This growing body of knowledge will serve as a basis for the rational design of regenerative therapies based on endogenous MSC recruitment. Successful endogenous MSC recruitment is the first step of successful tissue regeneration.

  4. A comparative study of regenerated bamboo, cotton and viscose ...

    African Journals Online (AJOL)

    Very little information is available about the validation of these properties through scientific research studies. It is also evident that information about natural bamboo and regenerated bamboo fibre products is often confusing. Regenerated bamboo (also referred to as bamboo viscose or bamboo rayon) is manufactured from ...

  5. Highly efficient in vitro adventitious shoot regeneration of Adenosma ...

    African Journals Online (AJOL)

    Adenosma glutinosum (Linn.) Druce is an important aromatic plant, but no information is available regarding its regeneration, callus induction and proliferation from leaf explants. In this study, an in vitro shoot regeneration procedure was developed for native A. glutinosum using leaf explants. Callus induction and shoots ...

  6. Somatic embryogenesis and plant regeneration from leaf explants of ...

    African Journals Online (AJOL)

    An attempt was made to study the somatic embryogenesis and plant regeneration from the in vitro leaf explants of Rumex vesicarius L. a renowned medicinal plant, which belongs to polygonaceae family. Effective in vitro regeneration of R. vesicarius was achieved via young leaf derived somatic embryo cultures.

  7. Numerical modeling and analysis of the active magnetic regenerator

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein

    of the AMR. The model simulates a regenerator made of parallel plates. The operating parameters, such as uid ow rates, thermal utilization, magnetocaloric properties etc. are varied as are geometric properties such as plate and channel thickness, regenerator length and porosity. In this way the performance...

  8. Influence of epidermal growth factor on liver regeneration after partial hepatectomy in rats

    DEFF Research Database (Denmark)

    Olsen, Peter Skov; Boesby, S.; Kirkegaard, P.

    2013-01-01

    The role of epidermal growth factor on liver regeneration after partial hepatectomy in rats was investigated. After a 70% hepatectomy in rats, the concentration of epidermal growth factor in portal venous blood was unchanged compared with unoperated controls. However, small amounts of epidermal...... growth factor could be identified in portal venous blood after intestinal instillation of epidermal growth factor. Brunner's glands and the submandibular glands secrete epidermal growth factor. Extirpation of Brunner's glands decreased liver regeneration, whereas removal of the submandibular glands had...... no effect on liver regeneration. Epidermal growth factor antiserum reduced liver regeneration significantly. Oral or s.c. administration of epidermal growth factor had no effect on liver regeneration, whereas epidermal growth factor enhanced the effect of insulin and glucagon on liver regeneration...

  9. Analytic models of NH4+ uptake and regeneration experiments

    International Nuclear Information System (INIS)

    Laws, E.A.

    1985-01-01

    Differential equations describing the uptake and regeneration of NH 4 + in both laboratory and field experiments are shown to have analytic solutions which can easily be inverted to determine the rate constants of interest. The solutions are used to study the descriptive ability of two fundamentally different models of NH 4 + cycling, one in which NH 4 + regeneration is regarded as a process that transfers N from participate N to NH 4 + , the other in which regeneration is regarded as a process that introduced NH 4 + to the dissolved phase without removing N from the particulate phase. The former model was found to give a good description of experimental field data and reasonable parameter values in all cases studied. The latter model was much less successful in describing the data and in producing reasonable parameter values. It is concluded that transfer of nitrogen from particulate N to NH 4 + is a process which must be taken into account in analyzing NH 4 + uptake and regeneration experiments

  10. Continuous cryopump with a device for regenerating the cryosurface

    International Nuclear Information System (INIS)

    Foster, C.A.

    1988-01-01

    A cryopump adapted for regeneration during cryopumping operation for a selected gas is described comprising: a pump housing defining an interior volume; a cryopumping surface within the interior volume of the pump housing in fluid communication with an inlet for the gas; cryogenic cooling means in thermal contact with the cryopumping surface, the cooling means and the cryopumping surface maintained at a temperature substantially less than the gas to condense the gas and produce a condensate of the gas on the cryopumping surface; a cryopumping surface regeneration means for selectively removing the condensate from the cryopumping surface and expelling the removed condensate from the cryopump while the cryopump is in operation whereby the cryopump can continuously operate without thermal cycling of the cryopumping surface while the cryopumping surface is being regenerated, the surface regeneration means defining a secondary chamber proximate the cryopumping surface to remove and to receive the removed condensate without affecting pressure within the cryopump

  11. Characterisation of cellulose films regenerated from acetone/water coagulants.

    Science.gov (United States)

    Geng, Hongjuan; Yuan, Zaiwu; Fan, Qingrui; Dai, Xiaonan; Zhao, Yue; Wang, Zhaojiang; Qin, Menghua

    2014-02-15

    A precooled aqueous solution of 7 wt% NaOH/12 wt% urea was used to dissolve cellulose up to a concentration of 2 wt%, which was then coagulated in an acetone/water mixture to regenerate cellulose film. The volume ratio of acetone to water (φ) had a dominant influence on film dimensional stability, film-forming ability, micromorphology, and mechanical strength. The film regenerated at φ=2.0 showed excellent performance in both dimensional stability and film-forming ability. Compared to that from pure acetone, the cellulose film from the acetone/water mixture with φ=2.0 was more densely interwoven, since the cellulosic fibrils formed during regeneration had pores with smaller average diameter. The alkali capsulated in the film during film formation could be released at quite a slow rate into the surrounding aqueous solution. The regenerated cellulose film with adjustable structure and properties may have potential applications in drug release and ultra filtration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Dependence of regenerated sensory axons on continuous neurotrophin-3 delivery.

    Science.gov (United States)

    Hou, Shaoping; Nicholson, LaShae; van Niekerk, Erna; Motsch, Melanie; Blesch, Armin

    2012-09-19

    Previous studies have shown that injured dorsal column sensory axons extend across a spinal cord lesion site if axons are guided by a gradient of neurotrophin-3 (NT-3) rostral to the lesion. Here we examined whether continuous NT-3 delivery is necessary to sustain regenerated axons in the injured spinal cord. Using tetracycline-regulated (tet-off) lentiviral gene delivery, NT-3 expression was tightly controlled by doxycycline administration. To examine axon growth responses to regulated NT-3 expression, adult rats underwent a C3 dorsal funiculus lesion. The lesion site was filled with bone marrow stromal cells, tet-off-NT-3 virus was injected rostral to the lesion site, and the intrinsic growth capacity of sensory neurons was activated by a conditioning lesion. When NT-3 gene expression was turned on, cholera toxin β-subunit-labeled sensory axons regenerated into and beyond the lesion/graft site. Surprisingly, the number of regenerated axons significantly declined when NT-3 expression was turned off, whereas continued NT-3 expression sustained regenerated axons. Quantification of axon numbers beyond the lesion demonstrated a significant decline of axon growth in animals with transient NT-3 expression, only some axons that had regenerated over longer distance were sustained. Regenerated axons were located in white matter and did not form axodendritic synapses but expressed presynaptic markers when closely associated with NG2-labeled cells. A decline in axon density was also observed within cellular grafts after NT-3 expression was turned off possibly via reduction in L1 and laminin expression in Schwann cells. Thus, multiple mechanisms underlie the inability of transient NT-3 expression to fully sustain regenerated sensory axons.

  13. Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues.

    Science.gov (United States)

    Pei, Wuhong; Xu, Lisha; Huang, Sunny C; Pettie, Kade; Idol, Jennifer; Rissone, Alberto; Jimenez, Erin; Sinclair, Jason W; Slevin, Claire; Varshney, Gaurav K; Jones, MaryPat; Carrington, Blake; Bishop, Kevin; Huang, Haigen; Sood, Raman; Lin, Shuo; Burgess, Shawn M

    2018-01-01

    Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration.

  14. Predicting the regeneration of Appalachian hardwoods: adapting the REGEN model for the Appalachian Plateau

    Science.gov (United States)

    Lance A. Vickers; Thomas R. Fox; David L. Loftis; David A. Boucugnani

    2013-01-01

    The difficulty of achieving reliable oak (Quercus spp.) regeneration is well documented. Application of silvicultural techniques to facilitate oak regeneration largely depends on current regeneration potential. A computer model to assess regeneration potential based on existing advanced reproduction in Appalachian hardwoods was developed by David...

  15. Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

    OpenAIRE

    M. Jesus Sanchez-Montero; Jennifer Pelaz; Nicolas Martin-Sanchez; Carmen Izquierdo; Francisco Salvador

    2018-01-01

    The properties of supercritical CO2 (SCCO2) and supercritical water (SCW) turn them into fluids with a great ability to remove organic adsorbates retained on solids. These properties were used herein to regenerate an activated carbon fiber (ACF) saturated with a pollutant usually contained in wastewater and drinking water, phenol. Severe regeneration conditions, up to 225 bar and 400 °C, had to be employed in SCCO2 regeneration to break the strong interaction established between phenol and th...

  16. Behavior of the turbine - regenerating preheaters functional assembly

    International Nuclear Information System (INIS)

    Bigu, Melania; Nita, Iulian Pavel; Tenescu, Mircea

    2004-01-01

    In the classical calculation of pressure distribution in the turbine-regenerating heaters' assembly a uniform distribution of feedwater enthalpy rise at each regenerating preheating step is usually assumed. This is accurately enough as a basis of designing of the preheating installation operating at rated power regime. But at partial regimes this is not totally valid since the preheaters are already shaped and the quasi-equal distribution does not satisfy the equation system describing the heat transfer correlations in these installations. A more detailed analysis shows that pressure in the feeding line preheaters and the bleeding steam flow rates at the turbine outlets are described physically by solving simultaneously the equations of hydrodynamic flow through the turbine and the equations of the heat transfer in the preheaters of the feedwater preheating line. This work approaches this more accurate solving method at least from a theoretical standing point; two cases are illustrated in the annexes of the work: a case of a secondary circuit with a single regenerating inlet and a case with two regenerating inlets. A classical - Panzer method of transformation of a many regenerative stages scheme may lead to one or another of the above cases. (authors)

  17. 3D printing strategies for peripheral nerve regeneration.

    Science.gov (United States)

    Petcu, Eugen B; Midha, Rajiv; McColl, Erin; Popa-Wagner, Aurel; Chirila, Traian V; Dalton, Paul D

    2018-03-23

    After many decades of biomaterials research for peripheral nerve regeneration, a clinical product (the nerve guide), is emerging as a proven alternative for relatively short injury gaps. This review identifies aspects where 3D printing can assist in improving long-distance nerve guide regeneration strategies. These include (1) 3D printing of the customizable nerve guides, (2) fabrication of scaffolds that fill nerve guides, (3) 3D bioprinting of cells within a matrix/bioink into the nerve guide lumen and the (4) establishment of growth factor gradients along the length a nerve guide. The improving resolution of 3D printing technologies will be an important factor for peripheral nerve regeneration, as fascicular-like guiding structures provide one path to improved nerve guidance. The capability of 3D printing to manufacture complex structures from patient data based on existing medical imaging technologies is an exciting aspect that could eventually be applied to treating peripheral nerve injury. Ultimately, the goal of 3D printing in peripheral nerve regeneration is the automated fabrication, potentially customized for the patient, of structures within the nerve guide that significantly outperform the nerve autograft over large gap injuries.

  18. Continuous microwave regeneration apparatus for absorption media

    Science.gov (United States)

    Smith, Douglas D.

    1999-01-01

    A method and apparatus for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

  19. Decision support tool for used oil regeneration technologies assessment and selection.

    Science.gov (United States)

    Khelifi, Olfa; Dalla Giovanna, Fabio; Vranes, Sanja; Lodolo, Andrea; Miertus, Stanislav

    2006-09-01

    Regeneration is the most efficient way of managing used oil. It saves money by preventing costly cleanups and liabilities that are associated with mismanagement of used oil, it helps to protect the environment and it produces a technically renewable resource by enabling an indefinite recycling potential. There are a variety of processes and licensors currently offering ways to deal with used oils. Selecting a regeneration technology for used oil involves "cross-matching" key criteria. Therefore, the first prototype of spent oil regeneration (SPORE), a decision support tool, has been developed to help decision-makers to assess the available technologies and select the preferred used oil regeneration options. The analysis is based on technical, economical and environmental criteria. These criteria are ranked to determine their relative importance for a particular used oil regeneration project. The multi-criteria decision analysis (MCDA) is the core of the SPORE using the PROMETHEE II algorithm.

  20. Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering

    Science.gov (United States)

    Nau, Thomas; Teuschl, Andreas

    2015-01-01

    Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon. PMID:25621217

  1. The genetic regulation of the terminating phase of liver regeneration

    DEFF Research Database (Denmark)

    Nygård, Ingvild E.; Mortensen, Kim E.; Hedegaard, Jakob

    2012-01-01

    Background After partial hepatectomy (PHx), the liver regeneration process terminates when the normal liver-mass/body-weight ratio of 2.5% has been re-established. To investigate the genetic regulation of the terminating phase of liver regeneration, we performed a 60% PHx in a porcine model. Liver...... biopsies were taken at the time of resection, after three weeks and upon termination the sixth week. Gene expression profiles were obtained using porcine oligonucleotide microarrays. Our study reveals the interactions between genes regulating the cell cycle, apoptosis and angiogenesis, and the role...... of Transforming Growth Factor-β (TGF-β) signalling towards the end of liver regeneration. Results Microarray analysis revealed a dominance of genes regulating apoptosis towards the end of regeneration. Caspase Recruitment Domain-Containing Protein 11 (CARD11) was up-regulated six weeks after PHx, suggesting...

  2. Spontaneous axonal regeneration in rodent spinal cord after ischemic injury

    DEFF Research Database (Denmark)

    von Euler, Mia; Janson, A M; Larsen, Jytte Overgaard

    2002-01-01

    cells, while other fibers were unmyelinated. Immunohistochemistry demonstrated that some of the regenerated fibers were tyrosine hydroxylase- or serotonin-immunoreactive, indicating a central origin. These findings suggest that there is a considerable amount of spontaneous regeneration after spinal cord......Here we present evidence for spontaneous and long-lasting regeneration of CNS axons after spinal cord lesions in adult rats. The length of 200 kD neurofilament (NF)-immunolabeled axons was estimated after photochemically induced ischemic spinal cord lesions using a stereological tool. The total...... length of all NF-immunolabeled axons within the lesion cavities was increased 6- to 10-fold at 5, 10, and 15 wk post-lesion compared with 1 wk post-surgery. In ultrastructural studies we found the putatively regenerating axons within the lesion to be associated either with oligodendrocytes or Schwann...

  3. Myocardial regeneration potential of adipose tissue-derived stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xiaowen, E-mail: baixw01@yahoo.com [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States); Alt, Eckhard, E-mail: ealt@mdanderson.org [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States)

    2010-10-22

    Research highlights: {yields} Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. {yields} For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. {yields} This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the

  4. Myocardial regeneration potential of adipose tissue-derived stem cells

    International Nuclear Information System (INIS)

    Bai, Xiaowen; Alt, Eckhard

    2010-01-01

    Research highlights: → Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. → For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. → This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the underlying

  5. Factors affecting callus and protoplast production and regeneration of plants from garlic tissue cultures

    International Nuclear Information System (INIS)

    Al-Safadi, B.; Nabulsi, I.

    2001-08-01

    Five cultivars of garlic, two explants, six callusing media, six regeneration media, two kinds of light and several doses of gamma irradiation were used to determine the best conditions for callus induction and plant regeneration from garlic tissue cultures. Also, some experiments were conducted to study the possibility to isolate protoplast and regenerate plants. The experiment showed that medium MS9 was good for regenerating plant directly from basal plate without going through callus phase. ANOVA exhibited significant differences among used cultivars in their ability to form callus. No significant difference was observed between 16 hr light and complete darkness in callus growth. However, appearance of callus was generally better on darkness. Cultivar varied in their ability to regenerate and interaction between cultivars and media was observed. Cultivar kisswany was the best in regeneration (38%) and medium MS47 was the best among used media (35%). Light type played a significant role in regeneration of plants where red light was much better than white light in inducing regeneration (68% vs 36%). ANOVA revealed significant effect of low doses of gamma irradiation on stimulation regeneration of plant whereas high doses prevented regeneration. Many experiments were conducted to isolate protoplast and regenerate plants. The best method for culturing was the droplet and the best conditions for incubation were complete darkness at 25 Degreed centigrade. This lead to formation of cell wall but no cell division was observed (author)

  6. Analytical expression for the bit error rate of cascaded all-optical regenerators

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Bischoff, S.

    2003-01-01

    We derive an approximate analytical expression for the bit error rate of cascaded fiber links containing all-optical 2R-regenerators. A general analysis of the interplay between noise due to amplification and the degree of reshaping (nonlinearity) of the regenerator is performed.......We derive an approximate analytical expression for the bit error rate of cascaded fiber links containing all-optical 2R-regenerators. A general analysis of the interplay between noise due to amplification and the degree of reshaping (nonlinearity) of the regenerator is performed....

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

    Science.gov (United States)

    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.

  8. Deep-time evolution of regeneration and preaxial polarity in tetrapod limb development.

    Science.gov (United States)

    Fröbisch, Nadia B; Bickelmann, Constanze; Olori, Jennifer C; Witzmann, Florian

    2015-11-12

    Among extant tetrapods, salamanders are unique in showing a reversed preaxial polarity in patterning of the skeletal elements of the limbs, and in displaying the highest capacity for regeneration, including full limb and tail regeneration. These features are particularly striking as tetrapod limb development has otherwise been shown to be a highly conserved process. It remains elusive whether the capacity to regenerate limbs in salamanders is mechanistically and evolutionarily linked to the aberrant pattern of limb development; both are features classically regarded as unique to urodeles. New molecular data suggest that salamander-specific orphan genes play a central role in limb regeneration and may also be involved in the preaxial patterning during limb development. Here we show that preaxial polarity in limb development was present in various groups of temnospondyl amphibians of the Carboniferous and Permian periods, including the dissorophoids Apateon and Micromelerpeton, as well as the stereospondylomorph Sclerocephalus. Limb regeneration has also been reported in Micromelerpeton, demonstrating that both features were already present together in antecedents of modern salamanders 290 million years ago. Furthermore, data from lepospondyl 'microsaurs' on the amniote stem indicate that these taxa may have shown some capacity for limb regeneration and were capable of tail regeneration, including re-patterning of the caudal vertebral column that is otherwise only seen in salamander tail regeneration. The data from fossils suggest that salamander-like regeneration is an ancient feature of tetrapods that was subsequently lost at least once in the lineage leading to amniotes. Salamanders are the only modern tetrapods that retained regenerative capacities as well as preaxial polarity in limb development.

  9. The effect of hypergravity on the lens, cornea and tail regeneration in Urodela

    Science.gov (United States)

    Grigoryan, E. N.; Dvorochkin, N.; Poplinskaya, V. A.; Yousuf, R.; Radugina, E. A.; Almeida, E. A.

    2017-09-01

    In previous experiments onboard Russian Bion/Foton satellites it was found that exposure to microgravity causes changes in eye lens regeneration of Urodela. The changes included higher rate of regeneration, increased cell proliferation in lens anlage, and synchronization of lens restoration. Similar changes were observed regarding tail regeneration. Recently, investigations were performed to find out whether exposure to hypergravity could also alter lens, cornea and tail regeneration in the newt P. waltl. Nine days prior to exposure the left lens was surgically removed through corneal incision and distal 1/3 of the tail was amputated, thus initiating regeneration. The experimental animals were allowed to recover for 9 days at 1 g and then exposed to 2 g for 12 days in an 8 ft diameter centrifuge at NASA Ames Research Center. The experimental animals were divided into 1 g controls, 2 g centrifugation animals, basal controls, and aquarium controls. Lens and corneal regeneration appeared to be inhibited in 2 g group compared to 1 g animals. In all 1 g controls, lens regeneration reached stages VII-IX in a synchronous fashion and corneal regeneration was nearly complete. In the 2 g newts, neural retinal detachment from the pigmented epithelium was seen in most operated eyes. It was also observed in the non-operated (right) eyes of the animals exposed to 2 g. The level of retinal detachment varied and could have been caused by hypergravity-induced high intraocular pressure. Regeneration (when it could be assessed) proceeded asynchronously, reaching stages from II to IX. Corneal restoration was also noticeably delayed and corneal morphology changed. Cell proliferation was measured using BrdU; the results were not comparable to the 1 g data because of retinal detachment. Previous investigations demonstrated that lens regeneration was controlled by the neural retina; therefore, lower regeneration rate at 2 g was, at least in part, associated with retinal detachment. FGF2

  10. Tissue Engineering Strategies in Ligament Regeneration

    Directory of Open Access Journals (Sweden)

    Caglar Yilgor

    2012-01-01

    Full Text Available Ligaments are dense fibrous connective tissues that connect bones to other bones and their injuries are frequently encountered in the clinic. The current clinical approaches in ligament repair and regeneration are limited to autografts, as the gold standard, and allografts. Both of these techniques have their own drawbacks that limit the success in clinical setting; therefore, new strategies are being developed in order to be able to solve the current problems of ligament grafting. Tissue engineering is a novel promising technique that aims to solve these problems, by producing viable artificial ligament substitutes in the laboratory conditions with the potential of transplantation to the patients with a high success rate. Direct cell and/or growth factor injection to the defect site is another current approach aiming to enhance the repair process of the native tissue. This review summarizes the current approaches in ligament tissue engineering strategies including the use of scaffolds, their modification techniques, as well as the use of bioreactors to achieve enhanced regeneration rates, while also discussing the advances in growth factor and cell therapy applications towards obtaining enhanced ligament regeneration.

  11. Simulation of Temperature Fluctuations in Stirling Engine Regenerator Matrices

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegaard; Carlsen, Henrik; Thomsen, Per Grove

    2003-01-01

    The objective of this study has been to create a model for studying the effects of fluctuations in regenerator matrix temperatures on Stirling engine performance. A one-dimensional model with axial discretisation of engine components has been formulated using the balance equations for mass, energy...... and accurately calculated. Simulation results have been compared to experimental data for a 9 kW Stirling engine and reasonable agreement has been found over a wide range of operating conditions using Helium or Nitrogen as working gas. Simulation results indicate that fluctuations in the regenerator matrix...... temperatures have significant impact on the regenerator loss, the engine power output, and the cycle efficiency....

  12. High efficiency indirect shoot regeneration and hypericin content in ...

    African Journals Online (AJOL)

    USER

    2010-04-12

    Apr 12, 2010 ... opium poppy. Support of hormone-free medium on shoot regeneration from callus has also been underlined for sugarbeet (Doley and Saunders, 1989). In our study, obtained regenerants acclimatized readily, alived (94%) and are still continuing to grow in the greenhouse of our department. Cell or callus ...

  13. Reproducible and expedient rice regeneration system using in vitro ...

    African Journals Online (AJOL)

    Inevitable prerequisite for expedient regeneration in rice is the selection of totipotent explant and developing an apposite combination of growth hormones. Here, we reported a reproducible regeneration protocol in which basal segments of the stem of the in vitro grown rice plants were used as ex-plant. Using the protocol ...

  14. Human airway xenograft models of epithelial cell regeneration

    Directory of Open Access Journals (Sweden)

    Puchelle Edith

    2000-10-01

    Full Text Available Abstract Regeneration and restoration of the airway epithelium after mechanical, viral or bacterial injury have a determinant role in the evolution of numerous respiratory diseases such as chronic bronchitis, asthma and cystic fibrosis. The study in vivo of epithelial regeneration in animal models has shown that airway epithelial cells are able to dedifferentiate, spread, migrate over the denuded basement membrane and progressively redifferentiate to restore a functional respiratory epithelium after several weeks. Recently, human tracheal xenografts have been developed in immunodeficient severe combined immunodeficiency (SCID and nude mice. In this review we recall that human airway cells implanted in such conditioned host grafts can regenerate a well-differentiated and functional human epithelium; we stress the interest in these humanized mice in assaying candidate progenitor and stem cells of the human airway mucosa.

  15. Improving Mental Health Through the Regeneration of Deprived Neighborhoods: A Natural Experiment.

    Science.gov (United States)

    White, James; Greene, Giles; Farewell, Daniel; Dunstan, Frank; Rodgers, Sarah; Lyons, Ronan A; Humphreys, Ioan; John, Ann; Webster, Chris; Phillips, Ceri J; Fone, David

    2017-08-15

    Neighborhood-level interventions provide an opportunity to better understand the impact of neighborhoods on health. In 2001, the Welsh Government, United Kingdom, funded Communities First, a program of neighborhood regeneration delivered to the 100 most deprived of the 881 electoral wards in Wales. In this study, we examined the association between neighborhood regeneration and mental health. Information on regeneration activities in 35 intervention areas (n = 4,197 subjects) and 75 control areas (n = 6,695 subjects) was linked to data on mental health from a cohort study with assessments made in 2001 (before regeneration) and 2008 (after regeneration). Propensity score matching was used to estimate the change in mental health in intervention neighborhoods versus control neighborhoods. Baseline differences between intervention and control areas were of similar magnitude as produced by paired randomization of neighborhoods. Regeneration was associated with an improvement in the mental health of residents in intervention areas compared with control neighborhoods (β = 1.54, 95% confidence interval: 0.50, 2.59), suggesting a reduction in socioeconomic inequalities in mental health. There was a dose-response relationship between length of residence in regeneration neighborhoods and improvements in mental health (P-trend = 0.05). These results show that targeted regeneration of deprived neighborhoods can improve mental health. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

  16. Restoration of CpG Methylation in The Egf Promoter Region during Rat Liver Regeneration

    Science.gov (United States)

    Deming, Li; Ziwei, Li; Xueqiang, Guo; Cunshuan, Xu

    2015-01-01

    Epidermal growth factor (EGF) is an important factor for healing after tissue damage in diverse experimental models. It plays an important role in liver regeneration (LR). The objective of this experiment is to investigate the methylation variation of 10 CpG sites in the Egf promoter region and their relevance to Egf expression during rat liver regenera- tion. As a follow up of our previous study, rat liver tissue was collected after rat 2/3 partial hepatectomy (PH) during the re-organization phase (from days 14 to days 28). Liver DNA was extracted and modified by sodium bisulfate. The methylation status of 10 CpG sites in Egf promoter region was determined using bisulfite sequencing polymerase chain reaction (PCR), as BSP method. The results showed that 3 (sites 3, 4 and 9) out of 10 CpG sites have strikingly methylation changes during the re-organization phase compared to the regeneration phase (from 2 hours to 168 hours, P=0.002, 0.048 and 0.018, respectively). Our results showed that methylation modification of CpGs in the Egf promoter region could be restored to the status before PH operation and changes of methylation didn’t affect Egf mRNA expression during the re-organization phase. PMID:26464832

  17. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  18. Resonantly Enhanced Axion-Photon Regeneration

    CERN Document Server

    Sikivie, P; Van Bibber, K; Bibber, Karl van

    2007-01-01

    We point out that photon regeneration-experiments that search for the axion, or axion-like particles, may be resonantly enhanced by employing matched Fabry-Perot optical cavities encompassing both the axion production and conversion magnetic field regions. Compared to a simple photon regeneration experiment, which uses the laser in a single-pass geometry, this technique can result in a gain in rate of order ${\\cal F}^2$, where ${\\cal F}$ is the finesse of the cavities. This gain could feasibly be $10^{(10-12)}$, corresponding to an improvement in sensitivity in the axion-photon coupling, $g_{a\\gamma\\gamma}$ , of order ${\\cal F}^{1/2} \\sim 10^{(2.5-3)}$, permitting a practical purely laboratory search to probe axion-photon couplings not previously excluded by stellar evolution limits, or solar axion searches.

  19. Live-cell imaging: new avenues to investigate retinal regeneration

    Directory of Open Access Journals (Sweden)

    Manuela Lahne

    2017-01-01

    Full Text Available Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integrate and/or respond to sensory cues. In contrast, zebrafish (Danio rerio possess an endogenous capacity to regenerate lost neurons. Here, we will focus on the processes that lead to neuronal regeneration in the zebrafish retina. Dying retinal neurons release a damage signal, tumor necrosis factor α, which induces the resident radial glia, the Müller glia, to reprogram and re-enter the cell cycle. The Müller glia divide asymmetrically to produce a Müller glia that exits the cell cycle and a neuronal progenitor cell. The arising neuronal progenitor cells undergo several rounds of cell divisions before they migrate to the site of damage to differentiate into the neuronal cell types that were lost. Molecular and immunohistochemical studies have predominantly provided insight into the mechanisms that regulate retinal regeneration. However, many processes during retinal regeneration are dynamic and require live-cell imaging to fully discern the underlying mechanisms. Recently, a multiphoton imaging approach of adult zebrafish retinal cultures was developed. We will discuss the use of live-cell imaging, the currently available tools and those that need to be developed to advance our knowledge on major open questions in the field of retinal regeneration.

  20. Meniscus repair and regeneration: review on current methods and research potential

    Directory of Open Access Journals (Sweden)

    C Scotti

    2013-01-01

    Full Text Available Meniscus regeneration is an unsolved clinical challenge. Despite the wide acceptance of the degenerative consequences of meniscectomy, no surgical procedure has succeeded to date in regenerating a functional and long-lasting meniscal fibrocartilage. Research proposed a number of experimental approaches encompassing all the typical strategies of regenerative medicine: cell-free scaffolds, gene therapy, intra-articular delivery of progenitor cells, biological glues for enhanced bonding of reparable tears, partial and total tissue engineered meniscus replacement. None of these approaches has been completely successful and can be considered suitable for all patients, as meniscal tears require specific and patient-related treatments depending on the size and type of lesion. Recent advances in cell biology, biomaterial science and bioengineering (e.g., bioreactors have now the potential to drive meniscus regeneration into a series of clinically relevant strategies. In this tutorial paper, the clinical need for meniscus regeneration strategies will be explained, and past and current experimental studies on meniscus regeneration will be reported.